1
|
Kral M, Dendisova M, Svoboda J, Cernescu A, Svecova M, Johnson CM, Pop-Georgievski O, Matejka P. Nano-FTIR spectroscopy of surface confluent polydopamine films - What is the role of deposition time and substrate material? Colloids Surf B Biointerfaces 2024; 235:113769. [PMID: 38306803 DOI: 10.1016/j.colsurfb.2024.113769] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2023] [Revised: 01/20/2024] [Accepted: 01/24/2024] [Indexed: 02/04/2024]
Abstract
Polydopamine (PDA) is a widely used anchoring layer for multiple purposes. While simple to prepare, PDA is characterized by high chemical and topological diversity, which can limit its versatility. Unraveling the formation mechanism and physicochemical properties of continuous confluent layer and adherent nanoparticles on the nanoscale is crucial to further extend the prospective applications of PDA. Utilizing nano-FTIR spectroscopy, we investigate layers of PDA on three different substrates (silicon/silicon dioxide, nitrogen-doped titanium oxide, and gold substrates) at varying times of deposition (ToD). We observed a good correlation between the nano-FTIR and macroscopic FTIR spectra that reflected the changes in the relative abundance of PDA and polymerization intermediates as ToD increased. To gain analytical power, we utilized the principal component analysis (PCA) and extracted additional information from the resulting loadings spectral curves and data distribution in the score plots. We revealed a higher variability of the spectra of ultrathin surface confluent layers compared to the adherent nanoparticles. While the spectra of nanoparticles showed no apparent dependency on either ToD or the substrate material, the spectra of layers were highly affected by the increasing ToD and exhibited a rise in the absorption of PDA. Concomitantly, the spectra of layers grouped according to the substrate material at the lowest ToD point to the fact that the substrate material affects the PDA's initial physicochemical structure. The observed separation gradually diminished with the increasing ToD as the PDA physicochemical structure became less influenced by the substrate material.
Collapse
Affiliation(s)
- Martin Kral
- Department of Physical Chemistry, Faculty of Chemical Engineering, University of Chemistry and Technology, 166 28 Prague 6, Czech Republic
| | - Marcela Dendisova
- Department of Physical Chemistry, Faculty of Chemical Engineering, University of Chemistry and Technology, 166 28 Prague 6, Czech Republic.
| | - Jan Svoboda
- Department of Chemistry and Physics of Surfaces and Interfaces, Institute of Macromolecular Chemistry, Czech Academy of Sciences, 162 06 Prague 6, Czech Republic
| | - Adrian Cernescu
- Attocube systems AG, Eglfinger Weg 2, D-85540 Haar, Munich, Germany
| | - Marie Svecova
- Division of Surface and Corrosion Science, Department of Chemistry, KTH Royal Institute of Technology, SE-100 44 Stockholm, Sweden
| | - C Magnus Johnson
- Division of Surface and Corrosion Science, Department of Chemistry, KTH Royal Institute of Technology, SE-100 44 Stockholm, Sweden
| | - Ognen Pop-Georgievski
- Department of Chemistry and Physics of Surfaces and Interfaces, Institute of Macromolecular Chemistry, Czech Academy of Sciences, 162 06 Prague 6, Czech Republic
| | - Pavel Matejka
- Department of Physical Chemistry, Faculty of Chemical Engineering, University of Chemistry and Technology, 166 28 Prague 6, Czech Republic
| |
Collapse
|
2
|
Abitbol T, Kubat M, Brännvall E, Kotov N, Johnson CM, Nizamov R, Nyberg M, Miettunen K, Nordgren N, Stevanic JS, Guerreiro MP. Isolation of Mixed Compositions of Cellulose Nanocrystals, Microcrystalline Cellulose, and Lignin Nanoparticles from Wood Pulps. ACS Omega 2023; 8:21474-21484. [PMID: 37360452 PMCID: PMC10286283 DOI: 10.1021/acsomega.3c00295] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/15/2023] [Accepted: 05/08/2023] [Indexed: 06/28/2023]
Abstract
From a circular economy perspective, one-pot strategies for the isolation of cellulose nanomaterials at a high yield and with multifunctional properties are attractive. Here, the effects of lignin content (bleached vs unbleached softwood kraft pulp) and sulfuric acid concentration on the properties of crystalline lignocellulose isolates and their films are explored. Hydrolysis at 58 wt % sulfuric acid resulted in both cellulose nanocrystals (CNCs) and microcrystalline cellulose at a relatively high yield (>55%), whereas hydrolysis at 64 wt % gave CNCs at a lower yield (<20%). CNCs from 58 wt % hydrolysis were more polydisperse and had a higher average aspect ratio (1.5-2×), a lower surface charge (2×), and a higher shear viscosity (100-1000×). Hydrolysis of unbleached pulp additionally yielded spherical nanoparticles (NPs) that were <50 nm in diameter and identified as lignin by nanoscale Fourier transform infrared spectroscopy and IR imaging. Chiral nematic self-organization was observed in films from CNCs isolated at 64 wt % but not from the more heterogeneous CNC qualities produced at 58 wt %. All films degraded to some extent under simulated sunlight trials, but these effects were less pronounced in lignin-NP-containing films, suggesting a protective feature, but the hemicellulose content and CNC crystallinity may be implicated as well. Finally, heterogeneous CNC compositions obtained at a high yield and with improved resource efficiency are suggested for specific nanocellulose uses, for instance, as thickeners or reinforcing fillers, representing a step toward the development of application-tailored CNC grades.
Collapse
Affiliation(s)
- Tiffany Abitbol
- Institute
of Materials, School of Engineering, EPFL, 1015 Lausanne, Switzerland
- Bioeconomy
and Health, RISE Research Institutes of
Sweden, SE-114 28 Stockholm, Sweden
| | - Mikaela Kubat
- Bioeconomy
and Health, RISE Research Institutes of
Sweden, SE-114 28 Stockholm, Sweden
| | - Elisabet Brännvall
- Bioeconomy
and Health, RISE Research Institutes of
Sweden, SE-114 28 Stockholm, Sweden
| | - Nikolay Kotov
- Department
of Chemistry, KTH Royal Institute of Technology, SE-100 44 Stockholm, Sweden
| | - C. Magnus Johnson
- Department
of Chemistry, KTH Royal Institute of Technology, SE-100 44 Stockholm, Sweden
| | - Rustem Nizamov
- Department
of Mechanical and Materials Engineering, Faculty of Technology, University of Turku, FI-20014 Turku, Finland
| | - Mikael Nyberg
- Department
of Mechanical and Materials Engineering, Faculty of Technology, University of Turku, FI-20014 Turku, Finland
| | - Kati Miettunen
- Department
of Mechanical and Materials Engineering, Faculty of Technology, University of Turku, FI-20014 Turku, Finland
| | - Niklas Nordgren
- Bioeconomy
and Health, RISE Research Institutes of
Sweden, SE-114 28 Stockholm, Sweden
| | - Jasna S. Stevanic
- Bioeconomy
and Health, RISE Research Institutes of
Sweden, SE-114 28 Stockholm, Sweden
| | - Maria Pita Guerreiro
- Bioeconomy
and Health, RISE Research Institutes of
Sweden, SE-114 28 Stockholm, Sweden
| |
Collapse
|
3
|
Kotov N, Larsson PA, Jain K, Abitbol T, Cernescu A, Wågberg L, Johnson CM. Elucidating the fine-scale structural morphology of nanocellulose by nano infrared spectroscopy. Carbohydr Polym 2023; 302:120320. [PMID: 36604038 DOI: 10.1016/j.carbpol.2022.120320] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2022] [Revised: 11/01/2022] [Accepted: 11/06/2022] [Indexed: 11/13/2022]
Abstract
Nanoscale infrared (IR) spectroscopy and microscopy, enabling the acquisition of IR spectra and images with a lateral resolution of 20 nm, is employed to chemically characterize individual cellulose nanocrystals (CNCs) and cellulose nanofibrils (CNFs) to elucidate if the CNCs and CNFs consist of alternating crystalline and amorphous domains along the CNF/CNC. The high lateral resolution enables studies of the nanoscale morphology at different domains of the CNFs/CNCs: flat segments, kinks, twisted areas, and end points. The types of nanocellulose investigated are CNFs from tunicate, CNCs from cotton, and anionic and cationic wood-derived CNFs. All nano-FTIR spectra acquired from the different samples and different domains of the individual nanocellulose particles resemble a spectrum of crystalline cellulose, suggesting that the non-crystalline cellulose signal observed in macroscopic measurements of nanocellulose most likely originate from cellulose chains present at the surface of the nanocellulose particles.
Collapse
Affiliation(s)
- Nikolay Kotov
- Department of Chemistry, KTH Royal Institute of Technology, Teknikringen 29, SE-100 44 Stockholm, Sweden.
| | - Per A Larsson
- Department of Fibre and Polymer Technology, KTH Royal Institute of Technology, Teknikringen 56, SE-100 44 Stockholm, Sweden.
| | - Karishma Jain
- Department of Fibre and Polymer Technology, KTH Royal Institute of Technology, Teknikringen 56, SE-100 44 Stockholm, Sweden.
| | - Tiffany Abitbol
- RISE Research Institutes of Sweden, Drottning Kristinas väg 55, SE-114 28 Stockholm, Sweden.
| | - Adrian Cernescu
- Neaspec, Attocube systems AG, Eglfinger Weg 2, 85540 Haar, Germany.
| | - Lars Wågberg
- Department of Fibre and Polymer Technology, KTH Royal Institute of Technology, Teknikringen 56, SE-100 44 Stockholm, Sweden.
| | - C Magnus Johnson
- Department of Chemistry, KTH Royal Institute of Technology, Teknikringen 29, SE-100 44 Stockholm, Sweden.
| |
Collapse
|
4
|
Chang T, Babu RP, Zhao W, Johnson CM, Hedström P, Odnevall I, Leygraf C. High-Resolution Microscopical Studies of Contact Killing Mechanisms on Copper-Based Surfaces. ACS Appl Mater Interfaces 2021; 13:49402-49413. [PMID: 34618446 PMCID: PMC8532116 DOI: 10.1021/acsami.1c11236] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
The mechanisms of bacterial contact killing induced by Cu surfaces were explored through high-resolution studies based on combinations of the focused ion beam (FIB), scanning transmission electron microscopy (STEM), high-resolution TEM, and nanoscale Fourier transform infrared spectroscopy (nano-FTIR) microscopy of individual bacterial cells of Gram-positive Bacillus subtilis in direct contact with Cu metal and Cu5Zn5Al1Sn surfaces after high-touch corrosion conditions. This approach permitted subcellular information to be extracted from the bioinorganic interface between a single bacterium and Cu/Cu5Zn5Al1Sn surfaces after complete contact killing. Early stages of interaction between individual bacteria and the metal/alloy surfaces include cell leakage of extracellular polymeric substances (EPSs) from the bacterium and changes in the metal/alloy surface composition upon adherence of bacteria. Three key observations responsible for Cu-induced contact killing include cell membrane damage, formation of nanosized copper-containing particles within the bacteria cell, and intracellular copper redox reactions. Direct evidence of cell membrane damage was observed upon contact with both Cu metal and Cu5Zn5Al1Sn surfaces. Cell membrane damage permits copper to enter into the cell interior through two possible routes, as small fragmentized Cu2O particles from the corrosion product layer and/or as released copper ions. This results in the presence of intracellular copper oxide nanoparticles inside the cell. The nanosized particles consist primarily of CuO with smaller amounts of Cu2O. The existence of two oxidation states of copper suggests that intracellular redox reactions play an important role. The nanoparticle formation can be regarded as a detoxification process of copper, which immobilizes copper ions via transformation processes within the bacteria into poorly soluble or even insoluble nanosized Cu structures. Similarly, the formation of primarily Cu(II) oxide nanoparticles could be a possible way for the bacteria to deactivate the toxic effects induced by copper ions via conversion of Cu(I) to Cu(II).
Collapse
Affiliation(s)
- Tingru Chang
- Department
of Chemistry, Division of Surface and Corrosion Science, KTH Royal Institute of Technology, Drottning Kristinas väg 51, SE-100 44 Stockholm, Sweden
- AIMES—Center
for the Advancement of Integrated Medical and Engineering Sciences
at Karolinska Institutet, KTH Royal Institute
of Technology, SE-171 77 Stockholm, Sweden
- Department
of Neuroscience, Karolinska Institutet, SE-171 77 Stockholm, Sweden
| | - R. Prasath Babu
- Department
of Materials Science and Engineering, KTH
Royal Institute of Technology, SE-100 44 Stockholm, Sweden
| | - Weijie Zhao
- Department
of Chemistry, Division of Surface and Corrosion Science, KTH Royal Institute of Technology, Drottning Kristinas väg 51, SE-100 44 Stockholm, Sweden
| | - C. Magnus Johnson
- Department
of Chemistry, Division of Surface and Corrosion Science, KTH Royal Institute of Technology, Drottning Kristinas väg 51, SE-100 44 Stockholm, Sweden
| | - Peter Hedström
- Department
of Materials Science and Engineering, KTH
Royal Institute of Technology, SE-100 44 Stockholm, Sweden
| | - Inger Odnevall
- Department
of Chemistry, Division of Surface and Corrosion Science, KTH Royal Institute of Technology, Drottning Kristinas väg 51, SE-100 44 Stockholm, Sweden
- AIMES—Center
for the Advancement of Integrated Medical and Engineering Sciences
at Karolinska Institutet, KTH Royal Institute
of Technology, SE-171 77 Stockholm, Sweden
- Department
of Neuroscience, Karolinska Institutet, SE-171 77 Stockholm, Sweden
| | - Christofer Leygraf
- Department
of Chemistry, Division of Surface and Corrosion Science, KTH Royal Institute of Technology, Drottning Kristinas väg 51, SE-100 44 Stockholm, Sweden
| |
Collapse
|
5
|
Xu W, Mihhels K, Kotov N, Lepikko S, Ras RHA, Johnson CM, Pettersson T, Kontturi E. Solid-state polymer adsorption for surface modification: The role of molecular weight. J Colloid Interface Sci 2021; 605:441-450. [PMID: 34333417 DOI: 10.1016/j.jcis.2021.07.062] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2021] [Revised: 07/11/2021] [Accepted: 07/12/2021] [Indexed: 11/26/2022]
Abstract
HYPOTHESIS Solid-state polymer adsorption offers a distinct approach for surface modification. These ultrathin, so-called Guiselin layers can easily be obtained by placing a polymer melt in contact with an interface, followed by a removal of the non-adsorbed layer with a good solvent. While the mechanism of formation has been well established for Guiselin layers, their stability, crucial from the perspective of materials applications, is not. The stability is a trade-off in the entropic penalty between cooperative detachment of the number of segments directly adsorbed on the substrate and consecutively pinned monomers. EXPERIMENTS Experimental model systems of Guiselin layers of polystyrene (PS) on silicon wafers with native oxide layer on top were employed. The stability of the adsorbed layers was studied as a function of PS molecular weight and polydispersibility by various microscopic and spectroscopic tools as well as quasi-static contact angle measurements. FINDINGS Adsorbed layers from low molecular weight PS were disrupted with typical spinodal decomposition patterns whereas high molecular weight (>500 kDa) PS resulted in stable, continuous layers. Moreover, we show that Guiselin layers offer an enticing way to modify a surface, as demonstrated by adsorbed PS that imparts a hydrophobic character to initially hydrophilic silicon wafers.
Collapse
Affiliation(s)
- Wenyang Xu
- Department of Bioproducts and Biosystems, School of Chemical Engineering, Aalto University, P.O. Box 16300, FI-00076 Aalto, Finland; Department of Fibre and Polymer Technology, KTH Royal Institute of Technology, Teknikringen 56, 10044 Stockholm, Sweden.
| | - Karl Mihhels
- Department of Bioproducts and Biosystems, School of Chemical Engineering, Aalto University, P.O. Box 16300, FI-00076 Aalto, Finland
| | - Nikolay Kotov
- Department of Chemistry, KTH Royal Institute of Technology, Drottning Kristinas väg 51, SE-100 44 Stockholm, Sweden
| | - Sakari Lepikko
- Department of Applied Physics, School of Science, Aalto University, Espoo, Finland
| | - Robin H A Ras
- Department of Bioproducts and Biosystems, School of Chemical Engineering, Aalto University, P.O. Box 16300, FI-00076 Aalto, Finland; Department of Applied Physics, School of Science, Aalto University, Espoo, Finland
| | - C Magnus Johnson
- Department of Chemistry, KTH Royal Institute of Technology, Drottning Kristinas väg 51, SE-100 44 Stockholm, Sweden
| | - Torbjörn Pettersson
- Department of Fibre and Polymer Technology, KTH Royal Institute of Technology, Teknikringen 56, 10044 Stockholm, Sweden; Wallenberg Wood Science Centre, Department of Fibre and Polymer Technology, KTH Royal Institute of Technology, Teknikringen 56, 10044 Stockholm, Sweden.
| | - Eero Kontturi
- Department of Bioproducts and Biosystems, School of Chemical Engineering, Aalto University, P.O. Box 16300, FI-00076 Aalto, Finland.
| |
Collapse
|
6
|
Fritz BG, Alexander TR, Johnson CM, Mace EK, Milbrath BD, Hayes JC. Background concentrations of Argon-39 in shallow soil gas. J Environ Radioact 2021; 228:106513. [PMID: 33360017 DOI: 10.1016/j.jenvrad.2020.106513] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/02/2020] [Revised: 12/10/2020] [Accepted: 12/14/2020] [Indexed: 06/12/2023]
Abstract
While radioisotopes of noble gases are known to be indicators of underground nuclear explosions (UNE), McIntyre et al. (2017) was the first to report the presence of 39Ar in shallow soil gas in association with a decades old UNE. While this finding hinted at the potential application of 39Ar to be used as an indicator of a UNE, doing so would also require an understanding of the natural concentrations of 39Ar present in soil gas. Without knowing the expected range and variability of naturally occurring concentrations of 39Ar, it is difficult to determine what measured concentrations would be indicative of an elevated concentration. This paper presents results from 16 soil gas samples and three atmospheric air samples collected from various locations across the western United States. Shallow soil gas samples were collected into self-contained underwater breathing apparatus (SCUBA) tanks using a custom-built soil gas sampling system and then processed and analyzed for 39Ar. The measured concentrations of 39Ar varied from atmospheric air concentrations to about 3.5 times atmospheric air concentrations (58 mBq/m3). The results presented here represent the first measurements of natural background 39Ar concentrations in shallow soil gas. This data will be necessary if 39Ar is to be used as an indicator of UNE.
Collapse
Affiliation(s)
- B G Fritz
- Pacific Northwest National Laboratory, 902 Battelle Blvd, Richland, WA, 99454, United States.
| | - T R Alexander
- Pacific Northwest National Laboratory, 902 Battelle Blvd, Richland, WA, 99454, United States
| | - C M Johnson
- Pacific Northwest National Laboratory, 902 Battelle Blvd, Richland, WA, 99454, United States
| | - E K Mace
- Pacific Northwest National Laboratory, 902 Battelle Blvd, Richland, WA, 99454, United States
| | - B D Milbrath
- Pacific Northwest National Laboratory, 902 Battelle Blvd, Richland, WA, 99454, United States
| | - J C Hayes
- Pacific Northwest National Laboratory, 902 Battelle Blvd, Richland, WA, 99454, United States
| |
Collapse
|
7
|
Zhao W, Göthelid M, Hosseinpour S, Johansson MB, Li G, Leygraf C, Johnson CM. The nature of self-assembled octadecylphosphonic acid (ODPA) layers on copper substrates. J Colloid Interface Sci 2021; 581:816-825. [PMID: 32818682 DOI: 10.1016/j.jcis.2020.07.058] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2020] [Revised: 07/10/2020] [Accepted: 07/11/2020] [Indexed: 11/19/2022]
Abstract
HYPOTHESIS The self-assembly of amphiphilic molecules onto solid substrates can result both in the formation of monolayers and multilayers. However, on oxidized and non-oxidized copper (Cu), only monolayer formation was reported for phosphonic acids possessing one phosphate head group. Here, the adsorption of octadecylphosphonic acid (ODPA) on Cu substrates through a self-assembly process was investigated with the initial hypothesis of monolayer formation. EXPERIMENTS The relative amount of ODPA adsorbed on a Cu substrate was determined by infrared reflection/absorption spectroscopy (IRRAS) and by atomic force microscopy (AFM) investigations before and after ODPA deposition. X-ray photoelectron spectroscopy (XPS) with sputtering was used to characterize the nature of the layers. FINDINGS The results show that the thickness of the ODPA layer increased with deposition time, and after 1 h a multilayer film with a thickness of some tens of nm was formed. The film was robust and required long-time sonication for removal. The origin of the film robustness was attributed to the release of Cu ions, resulting in the formation of Cu-ODPA complexes with Cu ions in the form of Cu(I). Preadsorbing a monolayer of octadecylthiol (ODT) onto the Cu resulted in no ODPA adsorption, since the release of Cu(I) ions was abolished.
Collapse
Affiliation(s)
- Weijie Zhao
- KTH Royal Institute of Technology, Department of Chemistry, Division of Surface and Corrosion Science, SE-100 44 Stockholm, Sweden.
| | - Mats Göthelid
- KTH Royal Institute of Technology, Department of Applied Physics, Material and Nano Physics, SE-164 40 Stockholm, Sweden.
| | - Saman Hosseinpour
- Institute of Particle Technology (LFG), Friedrich-Alexander-Universität-Erlangen-Nürnberg (FAU), 91058 Erlangen, Germany.
| | - Malin B Johansson
- Department of Chemistry Ångström Laboratory, Division of Physical Chemistry, Uppsala University, SE-751 20 Uppsala, Sweden.
| | - Gen Li
- KTH Royal Institute of Technology, Department of Chemistry, Division of Surface and Corrosion Science, SE-100 44 Stockholm, Sweden.
| | - Christofer Leygraf
- KTH Royal Institute of Technology, Department of Chemistry, Division of Surface and Corrosion Science, SE-100 44 Stockholm, Sweden.
| | - C Magnus Johnson
- KTH Royal Institute of Technology, Department of Chemistry, Division of Surface and Corrosion Science, SE-100 44 Stockholm, Sweden.
| |
Collapse
|
8
|
Kästner B, Johnson CM, Hermann P, Kruskopf M, Pierz K, Hoehl A, Hornemann A, Ulrich G, Fehmel J, Patoka P, Rühl E, Ulm G. Correction to Infrared Nanospectroscopy of Phospholipid and Surfactin Monolayer Domains. ACS Omega 2020; 5:15762. [PMID: 32637853 PMCID: PMC7331207 DOI: 10.1021/acsomega.0c02552] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/03/2020] [Indexed: 06/11/2023]
Abstract
[This corrects the article DOI: 10.1021/acsomega.7b01931.].
Collapse
|
9
|
Johnson CM, Patel NR, Makai GE, Huynh TQ. Interstitial Pregnancy and Laparoscopic Cornual Resection. J Minim Invasive Gynecol 2019. [DOI: 10.1016/j.jmig.2019.09.606] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
|
10
|
Patel NR, Johnson CM, Makai GE, Huynh TQ, Thompson D. 2262 Hysteroscopic Loop Resection Training Utilizing a Virtual Reality and Low-Fidelity Model: a Pilot Study. J Minim Invasive Gynecol 2019. [DOI: 10.1016/j.jmig.2019.09.258] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
|
11
|
Johnson CM, Makai GE, Patel NR, Huynh TQ. Laparoscopic Isthmocele Repair. J Minim Invasive Gynecol 2019. [DOI: 10.1016/j.jmig.2019.09.542] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
|
12
|
Agyakwa P, Dai J, Li J, Mouawad B, Yang L, Corfield M, Johnson CM. Three-dimensional damage morphologies of thermomechanically deformed sintered nanosilver die attachments for power electronics modules. J Microsc 2019; 277:140-153. [PMID: 31070241 PMCID: PMC7186834 DOI: 10.1111/jmi.12803] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2019] [Revised: 04/26/2019] [Accepted: 05/07/2019] [Indexed: 11/28/2022]
Abstract
A time-lapse study of thermomechanical fatigue damage has been undertaken using three-dimensional X-ray computer tomography. Morphologies were extracted from tomography data and integrated with data from microscopy modalities at different resolution levels. This enables contextualization of some of the fine-scale properties which underpin the large-scale damage observed via tomography. Lateral views of crack development are presented, which show networks analogous to mud-cracks. Crack fronts which develop in the most porous regions within the sintered attachment layer travel across the boundary into the copper substrate. The propagation characteristics of these cracks within the substrate are analysed. Evidence is provided of heterogeneous densification within the sintered joint under power cycling, and this is shown to play a major role in driving the initiation and propagation of the cracks. Examination of the texture (differing levels of X-ray absorption) of virtual cross-sectional images reveals the origins of the nonuniformity of densification. Finally, cracks within the sintered joint are shown to have a negligible impact on the conduction pathway of the joint due to their aspect ratio and orientation with respect to the assembly. LAY DESCRIPTION: This paper concerns the use of three-dimensional (3D) X-ray tomography, a nondestructive technique, to perform cradle-to-grave studies of sintered nanosilver die-attachments under operation. Sintered nanosilver die-attachments have been proposed as a more reliable and environmentally friendly alternative to solder alloy joints for emerging power electronics module designs. However, their degradation mechanisms are not as well understood. This same sample-study is about observing how the fine-scale structure of a sintered attachment evolves and degrades over time. Using 3D tomography affords otherwise infeasible perspectives, such as virtual cross-sections in the lateral plane of the attachment. These perspectives provide qualitative information which elucidates the degradation mechanisms. They demonstrate, for example, that the structure of the sintered attachment densifies under operation, and a consequence of this is the formation of shrinkage cracks in the most porous regions, much like mud-cracks. Other imaging techniques (metallographic etching and scanning electron microscopy) have been used in correlation with 3D renderings of these cracks to analyse their propagation and reveal their relationship both with the internal structure of the sintered attachment itself, and the structure of the substrate to which it is joined. It is shown that the cracks develop within the sintered attachment layer and eventually cross over into the substrate. A comparison of two sintered attachments with contrasting bulk porosities allows the effect of initial bond quality on crack development to be examined.
Collapse
Affiliation(s)
- P Agyakwa
- Department of Electrical & Electronic Engineering, University of Nottingham, University Park, Nottingham, UK
| | - J Dai
- Department of Electrical & Electronic Engineering, University of Nottingham, University Park, Nottingham, UK
| | - J Li
- Dynex Semiconductor Ltd, Doddington Road, Lincoln, UK
| | - B Mouawad
- Department of Electrical & Electronic Engineering, University of Nottingham, University Park, Nottingham, UK
| | - L Yang
- Department of Electrical & Electronic Engineering, University of Nottingham, University Park, Nottingham, UK
| | - M Corfield
- Department of Electrical & Electronic Engineering, University of Nottingham, University Park, Nottingham, UK
| | - C M Johnson
- Department of Electrical & Electronic Engineering, University of Nottingham, University Park, Nottingham, UK
| |
Collapse
|
13
|
Johnson CM, Fitch K, Merola JF, Han J, Qureshi AA, Li WQ. Plasma levels of tumour necrosis factor-α and adiponectin can differentiate patients with psoriatic arthritis from those with psoriasis. Br J Dermatol 2019; 181:379-380. [PMID: 30695115 DOI: 10.1111/bjd.17700] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- C M Johnson
- Department of Dermatology, Warren Alpert Medical School, Brown University, Providence, RI, U.S.A
| | - K Fitch
- Department of Dermatology, Warren Alpert Medical School, Brown University, Providence, RI, U.S.A.,Warren Alpert Medical School, Brown University, Providence, RI, U.S.A
| | - J F Merola
- Department of Dermatology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, U.S.A.,Division of Rheumatology, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, U.S.A
| | - J Han
- Department of Epidemiology, Richard M. Fairbanks School of Public Health, Indiana University, Indianapolis, IN, U.S.A.,Melvin and Bren Simon Cancer Center, Indiana University, Indianapolis, IN, U.S.A
| | - A A Qureshi
- Department of Dermatology, Warren Alpert Medical School, Brown University, Providence, RI, U.S.A.,Department of Dermatology, Rhode Island Hospital, Providence, RI, U.S.A.,Department of Epidemiology, School of Public Health, Brown University, Providence, RI, U.S.A
| | - W-Q Li
- Department of Dermatology, Warren Alpert Medical School, Brown University, Providence, RI, U.S.A.,Department of Epidemiology, School of Public Health, Brown University, Providence, RI, U.S.A
| |
Collapse
|
14
|
Niga P, Hansson-Mille PM, Swerin A, Claesson PM, Schoelkopf J, Gane PAC, Dai J, Furó I, Campbell RA, Johnson CM. Propofol adsorption at the air/water interface: a combined vibrational sum frequency spectroscopy, nuclear magnetic resonance and neutron reflectometry study. Soft Matter 2018; 15:38-46. [PMID: 30516226 DOI: 10.1039/c8sm01677a] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Propofol is an amphiphilic small molecule that strongly influences the function of cell membranes, yet data regarding interfacial properties of propofol remain scarce. Here we consider propofol adsorption at the air/water interface as elucidated by means of vibrational sum frequency spectroscopy (VSFS), neutron reflectometry (NR), and surface tensiometry. VSFS data show that propofol adsorbed at the air/water interface interacts with water strongly in terms of hydrogen bonding and weakly in the proximity of the hydrocarbon parts of the molecule. In the concentration range studied there is almost no change in the orientation adopted at the interface. Data from NR show that propofol forms a dense monolayer with a thickness of 8.4 Å and a limiting area per molecule of 40 Å2, close to the value extracted from surface tensiometry. The possibility that islands or multilayers of propofol form at the air/water interface is therefore excluded as long as the solubility limit is not exceeded. Additionally, measurements of the 1H NMR chemical shifts demonstrate that propofol does not form dimers or multimers in bulk water up to the solubility limit.
Collapse
Affiliation(s)
- Petru Niga
- RISE Research Institutes of Sweden - Chemistry, Materials and Surfaces, Box 5607, SE-114 86 Stockholm, Sweden.
| | - Petra M Hansson-Mille
- RISE Research Institutes of Sweden - Chemistry, Materials and Surfaces, Box 5607, SE-114 86 Stockholm, Sweden.
| | - Agne Swerin
- RISE Research Institutes of Sweden - Chemistry, Materials and Surfaces, Box 5607, SE-114 86 Stockholm, Sweden. and KTH Royal Institute of Technology, Department of Chemistry, Division of Surface and Corrosion Science, SE-100 44 Stockholm, Sweden.
| | - Per M Claesson
- RISE Research Institutes of Sweden - Chemistry, Materials and Surfaces, Box 5607, SE-114 86 Stockholm, Sweden. and KTH Royal Institute of Technology, Department of Chemistry, Division of Surface and Corrosion Science, SE-100 44 Stockholm, Sweden.
| | | | - Patrick A C Gane
- Omya International AG, Baslerstrasse 42, CH-4665 Oftringen, Switzerland and Aalto University, School of Chemical Technology, Department of Bioproducts and Biosystems, FI-00076 Aalto, Helsinki, Finland
| | - Jing Dai
- KTH Royal Institute of Technology, Department of Chemistry, Division of Applied Physical Chemistry, SE-100 44 Stockholm, Sweden
| | - István Furó
- KTH Royal Institute of Technology, Department of Chemistry, Division of Applied Physical Chemistry, SE-100 44 Stockholm, Sweden
| | - Richard A Campbell
- Institut Laue-Langevin, 71 Avenue des Martyrs, CS20156, 38042 Grenoble Cedex 9, France and Division of Pharmacy and Optometry, University of Manchester, Manchester M13 9PT, UK
| | - C Magnus Johnson
- KTH Royal Institute of Technology, Department of Chemistry, Division of Surface and Corrosion Science, SE-100 44 Stockholm, Sweden.
| |
Collapse
|
15
|
Soponkanaporn S, Deakin CT, Schutz PW, Marshall LR, Yasin SA, Johnson CM, Sag E, Tansley SL, McHugh NJ, Wedderburn LR, Jacques TS. Expression of myxovirus-resistance protein A: a possible marker of muscle disease activity and autoantibody specificities in juvenile dermatomyositis. Neuropathol Appl Neurobiol 2018; 45:410-420. [PMID: 29770465 PMCID: PMC6563435 DOI: 10.1111/nan.12498] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2018] [Accepted: 05/01/2018] [Indexed: 12/15/2022]
Abstract
Aims To evaluate the relationship between expression of myxovirus‐resistance protein A (MxA) protein on muscle biopsies by immunohistochemistry and disease activity in juvenile dermatomyositis (JDM) patients. Also, another aim was to investigate whether the expression of MxA is related with myositis‐specific autoantibodies (MSA) status in JDM patients. Methods 103 patients (median aged 6.3, interquartile range 0.5–15.9) enrolled in the Juvenile Dermatomyositis Cohort and Biomarker Study (JDCBS). Muscle biopsies were stained with MxA and scored. Clinical data at initial presentation were collected and autoantibodies were analysed. Multiple linear regression analysis was performed to estimate the association between MxA expression on muscle fibres and muscle disease activity, and MSA status. Results Expression of MxA protein on JDM samples was identified in 61.2%. There was a significant association between MxA scores and Childhood Myositis Assessment Scale (CMAS) (P = 0.002), and Manual Muscle Testing of Eight Muscles (MMT8) (P = 0.026). CMAS and MMT8 scores were significantly lower in the group of patients with strong MxA expression. MxA scores differed according to MSA subgroups (P = 0.002). Patients with positive nuclear matrix protein 2 autoantibodies had strong MxA expression, whereas anti‐melanoma differentiation‐associated gene 5 positive patients had no or weak MxA expression. Conclusions This study reveals the significant association between level of MxA expression on muscle fibres and clinical measures of muscular disease activity in JDM patients and MSA status. This confirms type I interferonopathies in muscle fibres of JDM patients which could help with improving treatment outcome in JDM patients and underscoring the distinct pathophysiological pathways in different MSA status.
Collapse
Affiliation(s)
- S Soponkanaporn
- Infection, Immunity and Inflammation Programme, UCL Great Ormond Street Institute of Child Health, London, UK.,Division of Rheumatology, Department of Pediatrics, Faculty of Medicine Ramathibodi Hospital, Mahidol University, Bangkok, Thailand
| | - C T Deakin
- Infection, Immunity and Inflammation Programme, UCL Great Ormond Street Institute of Child Health, London, UK
| | - P W Schutz
- Infection, Immunity and Inflammation Programme, UCL Great Ormond Street Institute of Child Health, London, UK.,Division of Neuropathology, Vancouver General Hospital, Vancouver, BC, Canada.,Department of Pathology, University of British Columbia, Vancouver, BC, Canada
| | - L R Marshall
- Infection, Immunity and Inflammation Programme, UCL Great Ormond Street Institute of Child Health, London, UK
| | - S A Yasin
- Infection, Immunity and Inflammation Programme, UCL Great Ormond Street Institute of Child Health, London, UK
| | - C M Johnson
- Infection, Immunity and Inflammation Programme, UCL Great Ormond Street Institute of Child Health, London, UK
| | - E Sag
- Infection, Immunity and Inflammation Programme, UCL Great Ormond Street Institute of Child Health, London, UK.,Department of Pediatric Rheumatology, Faculty of Medicine, Hacettepe University, Ankara, Turkey
| | - S L Tansley
- Department of Pharmacy and Pharmacology, University of Bath, Bath, UK
| | - N J McHugh
- Department of Pharmacy and Pharmacology, University of Bath, Bath, UK
| | - L R Wedderburn
- Infection, Immunity and Inflammation Programme, UCL Great Ormond Street Institute of Child Health, London, UK.,Rheumatology Unit, Great Ormond Street Hospital for Children, London, UK.,NIHR Biomedical Research Centre at Great Ormond Street Hospital for Children, NHS Foundation Trust and University College London, London, UK.,Arthritis Research UK Centre for Adolescent Rheumatology at UCL, UCLH and GOSH, London, UK
| | - T S Jacques
- Developmental Biology and Cancer Programme, UCL Great Ormond Street Institute of Child Health, London, UK
| |
Collapse
|
16
|
Kästner B, Johnson CM, Hermann P, Kruskopf M, Pierz K, Hoehl A, Hornemann A, Ulrich G, Fehmel J, Patoka P, Rühl E, Ulm G. Infrared Nanospectroscopy of Phospholipid and Surfactin Monolayer Domains. ACS Omega 2018; 3:4141-4147. [PMID: 30023886 PMCID: PMC6044929 DOI: 10.1021/acsomega.7b01931] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/05/2017] [Accepted: 03/16/2018] [Indexed: 05/22/2023]
Abstract
A main challenge in understanding the structure of a cell membrane and its interactions with drugs is the ability to chemically study the different molecular species on the nanoscale. We have achieved this for a model system consisting of mixed monolayers (MLs) of the biologically relevant phospholipid 1,2-distearoyl-sn-glycero-phosphatidylcholine and the antibiotic surfactin. By employing nano-infrared (IR) microscopy and spectroscopy in combination with atomic force microscopy imaging, it was possible to identify and chemically detect domain formation of the two constituents as well as to obtain IR spectra of these species with a spatial resolution on the nanoscale. A novel method to enhance the near-field imaging contrast of organic MLs by plasmon interferometry is proposed and demonstrated. In this technique, the organic layer is deposited on gold and ML graphene substrates, the latter of which supports propagating surface plasmons. Plasmon reflections arising from changes in the dielectric environment provided by the organic layer lead to an additional contrast mechanism. Using this approach, the interfacial region between surfactin and the phospholipid has been mapped and a transition region is identified.
Collapse
Affiliation(s)
- Bernd Kästner
- Physikalisch-Technische
Bundesanstalt (PTB), Abbestr. 2-12, 10587 Berlin, Germany
- E-mail: (B.K.)
| | - C. Magnus Johnson
- Department
of Chemistry, Division of Surface and Corrosion Science, KTH Royal Institute of Technology, SE-100 44 Stockholm, Sweden
| | - Peter Hermann
- Physikalisch-Technische
Bundesanstalt (PTB), Abbestr. 2-12, 10587 Berlin, Germany
| | - Mattias Kruskopf
- Physikalisch-Technische
Bundesanstalt (PTB), Bundesallee 100, 38116 Braunschweig, Germany
| | - Klaus Pierz
- Physikalisch-Technische
Bundesanstalt (PTB), Bundesallee 100, 38116 Braunschweig, Germany
| | - Arne Hoehl
- Physikalisch-Technische
Bundesanstalt (PTB), Abbestr. 2-12, 10587 Berlin, Germany
| | - Andrea Hornemann
- Physikalisch-Technische
Bundesanstalt (PTB), Abbestr. 2-12, 10587 Berlin, Germany
| | - Georg Ulrich
- Physikalisch-Technische
Bundesanstalt (PTB), Abbestr. 2-12, 10587 Berlin, Germany
| | - Jakob Fehmel
- Physikalisch-Technische
Bundesanstalt (PTB), Abbestr. 2-12, 10587 Berlin, Germany
| | - Piotr Patoka
- Physikalische
Chemie, Institut für Chemie und Biochemie, Freie Universität Berlin, Takustr. 3, 14195 Berlin, Germany
| | - Eckart Rühl
- Physikalische
Chemie, Institut für Chemie und Biochemie, Freie Universität Berlin, Takustr. 3, 14195 Berlin, Germany
| | - Gerhard Ulm
- Physikalisch-Technische
Bundesanstalt (PTB), Abbestr. 2-12, 10587 Berlin, Germany
| |
Collapse
|
17
|
Johnson CM, Henderson MS, Tripicchio G, Rozin P, Heo M, Pietrobelli A, Berkowitz RI, Keller KL, Faith MS. Observed parent-child feeding dynamics in relation to child body mass index and adiposity. Pediatr Obes 2018; 13:222-231. [PMID: 28296242 DOI: 10.1111/ijpo.12209] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/24/2016] [Revised: 12/09/2016] [Accepted: 12/15/2016] [Indexed: 10/20/2022]
Abstract
BACKGROUND Restrictive feeding is associated with child overweight; however, the majority of studies used parent-report questionnaires. OBJECTIVES The relationship between child adiposity measures and directly observed parent and child behaviours were tested using a novel behavioural coding system (BCS). METHODS Data from 109 children, participants in a twin study and their mothers, were analyzed. Parent-child dyads were video-recorded twice in the laboratory, while children ate ad libitum from a buffet lunch. Mother and child behaviours were assessed using the BCS. Height, body weight and body fat were directly measured for each child. Associations between child adiposity measures and average BCS behaviour (i.e. pooled across visits) were tested using partial correlations adjusting for child age. RESULTS Regarding discouragement prompts, child body mass index (BMI) z-score was significantly associated with a greater rate of total discouragements (per minute, min-1 ), nonverbal discouragements (min-1 ) and temporary (delay) discouragements (min-1 ) (p < 0.05). Child percent body fat was associated with greater nonverbal discouragements (min-1 ). Regarding encouragement prompts, child BMI z-score was significantly associated with a greater rate of total encouragements (min-1 ), nonverbal encouragements (min-1 ) and reward encouragements (min-1 ). Child BMI z-score and percent body fat were both positively associated with greater maternal health encouragements (min-1 ). Associations with encouragement to eat prompts were no longer significant when accounting for the dependence among twins (being part of the same family). CONCLUSIONS Heavier children received greater maternal discouragements to eat and, with qualifications, encouragements to eat. The role of nonverbal parenting cues warrants further research regarding child eating regulation and obesity.
Collapse
Affiliation(s)
- C M Johnson
- Department of Nutrition, University of North Carolina at Chapel Hill, Chapel Hill, USA.,Center for Health Promotion and Disease Prevention, University of North Carolina at Chapel Hill, Chapel Hill, USA
| | | | - G Tripicchio
- Department of Nutrition, University of North Carolina at Chapel Hill, Chapel Hill, USA
| | - P Rozin
- Department of Psychology, University of Pennsylvania, Philadelphia, USA
| | - M Heo
- Department of Epidemiology and Population Health, Albert Einstein College of Medicine, Bronx, USA
| | - A Pietrobelli
- Pediatric Unit, Verona University Medical School, Verona, Italy.,Pennington Biomedical Research Center, Baton Rouge, USA
| | - R I Berkowitz
- The Children's Hospital of Philadelphia and The Perelman School of Medicine at the University of Pennsylvania, Philadelphia, USA
| | - K L Keller
- Department of Nutritional Sciences and Food Science, The Pennsylvania State University, State College, USA
| | - M S Faith
- Department of Counseling, School, and Educational Psychology, Graduate School of Education, University at Buffalo - SUNY, Buffalo, USA
| |
Collapse
|
18
|
Niga P, Hansson-Mille PM, Swerin A, Claesson PM, Schoelkopf J, Gane PAC, Bergendal E, Tummino A, Campbell RA, Magnus Johnson C. Interactions between model cell membranes and the neuroactive drug propofol. J Colloid Interface Sci 2018; 526:230-243. [PMID: 29734090 DOI: 10.1016/j.jcis.2018.03.052] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2017] [Revised: 03/12/2018] [Accepted: 03/14/2018] [Indexed: 12/13/2022]
Abstract
Vibrational sum frequency spectroscopy (VSFS) complemented by surface pressure isotherm and neutron reflectometry (NR) experiments were employed to investigate the interactions between propofol, a small amphiphilic molecule that currently is the most common general anaesthetic drug, and phospholipid monolayers. A series of biologically relevant saturated phospholipids of varying chain length from C18 to C14 were spread on either pure water or propofol (2,6-bis(1-methylethyl)phenol) solution in a Langmuir trough, and the change in the molecular structure of the film, induced by the interaction with propofol, was studied with respect to the surface pressure. The results from the surface pressure isotherm experiments revealed that propofol, as long as it remains at the interface, enhances the fluidity of the phospholipid monolayer. The VSF spectra demonstrate that for each phospholipid the amount of propofol in the monolayer region decreases with increasing surface pressure. Such squeeze out is in contrast to the enhanced interactions that can be exhibited by more complex amphiphilic molecules such as peptides. At surface pressures of 22-25 mN m-1, which are relevant for biological cell membranes, most of the propofol has been expelled from the monolayer, especially in the case of the C16 and C18 phospholipids that adopt a liquid condensed phase packing of its alkyl tails. At lower surface pressures of 5 mN m-1, the effect of propofol on the structure of the alkyl tails is enhanced when the phospholipids are present in a liquid expanded phase. Specifically, for the C16 phospholipid, NR data reveal that propofol is located exclusively in the head group region, which is rationalized in the context of previous studies. The results imply a non-homogeneous distribution of propofol in the plane of real cell membranes, which is an inference that requires urgent testing and may help to explain why such low concentration of the drug are required to induce general anaesthesia.
Collapse
Affiliation(s)
- Petru Niga
- RISE - Research Institute of Sweden, Bioscience and Materials - Surface, Process and Formulation Box 5607, SE-114 28 Stockholm, Sweden.
| | - Petra M Hansson-Mille
- RISE - Research Institute of Sweden, Bioscience and Materials - Surface, Process and Formulation Box 5607, SE-114 28 Stockholm, Sweden
| | - Agne Swerin
- RISE - Research Institute of Sweden, Bioscience and Materials - Surface, Process and Formulation Box 5607, SE-114 28 Stockholm, Sweden; KTH Royal Institute of Technology, Department of Chemistry, Division of Surface and Corrosion Science, SE-100 44 Stockholm, Sweden
| | - Per M Claesson
- RISE - Research Institute of Sweden, Bioscience and Materials - Surface, Process and Formulation Box 5607, SE-114 28 Stockholm, Sweden; KTH Royal Institute of Technology, Department of Chemistry, Division of Surface and Corrosion Science, SE-100 44 Stockholm, Sweden
| | | | - Patrick A C Gane
- Omya International AG, Baslerstrasse 42, CH-4665 Oftringen, Switzerland; Aalto University, School of Chemical Engineering, Department of Bioproducts and Biosystems, P.O. Box 16300, FI-00076 Aalto, Helsinki, Finland
| | - Erik Bergendal
- KTH Royal Institute of Technology, Department of Chemistry, Division of Surface and Corrosion Science, SE-100 44 Stockholm, Sweden
| | - Andrea Tummino
- Institut Laue-Langevin, 71 avenue des Martyrs, 38042 Grenoble, France; Eötvös Loránd University, Budapest 112, P.O. Box 32, H-1518, Hungary
| | | | - C Magnus Johnson
- KTH Royal Institute of Technology, Department of Chemistry, Division of Surface and Corrosion Science, SE-100 44 Stockholm, Sweden.
| |
Collapse
|
19
|
Pauw A, Johnson CM. Mutualism between co-occurring plant species in South Africa's Mediterranean climate heathland is mediated by birds. Plant Biol (Stuttg) 2018; 20 Suppl 1:224-230. [PMID: 28960844 DOI: 10.1111/plb.12635] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/30/2017] [Accepted: 09/21/2017] [Indexed: 06/07/2023]
Abstract
Interactions among plant species via pollinators vary from competitive to mutualistic and can influence the probability of stable coexistence of plant species. We aimed to determine the nature of the interaction via flower visitors between Leucospermum conocarpodendron and Mimetes fimbriifolius, two shrubs in the Proteaceae that share many ecological traits and coexist on the Cape Peninsula, South Africa. To assess the extent of pollinator sharing we analysed nectar properties and recorded the pollinator fauna, their behaviour and contribution to seed set. To test for competition via interspecific pollen transfer, we recorded the movement patterns of pollinators and quantified pollen loads. To determine the effect of co-flowering on visitation rates we recorded visits in stands that varied in the density of the two species. We found that the species produce similar rewards and share pollinating Cape Sugarbirds (Promerops cafer). Interspecific pollen transfer is avoided by placing pollen on different parts of the bird. Both species are visited by nectar-thieving Orange-breasted Sunbirds (Anthobaphes violacea). Insects and autonomous self-pollination contributed little to seed set. Pollinator visits increased with conspecific density in both species, and the slope of the increase was steepest in the presence of high densities of the co-occurring plant species. Nectar thief visits also increased with conspecific density in both species, but the slope declined with increasing density of the co-occurring species. Co-occurrence enhanced pollinator visits and alleviated nectar robbing in both plant species, consistent with mutualisms. Mutualism within a trophic level is unusual, but may help to explain the stable coexistence of ecologically similar species.
Collapse
Affiliation(s)
- A Pauw
- Department of Botany and Zoology, Stellenbosch University, Matieland, South Africa
| | - C M Johnson
- Department of Botany and Zoology, Stellenbosch University, Matieland, South Africa
| |
Collapse
|
20
|
Smith AJB, Beukes NJ, Gutzmer J, Czaja AD, Johnson CM, Nhleko N. Oncoidal granular iron formation in the Mesoarchaean Pongola Supergroup, southern Africa: Textural and geochemical evidence for biological activity during iron deposition. Geobiology 2017; 15:731-749. [PMID: 28846192 DOI: 10.1111/gbi.12248] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/21/2016] [Accepted: 06/21/2017] [Indexed: 06/07/2023]
Abstract
We document the discovery of the first granular iron formation (GIF) of Archaean age and present textural and geochemical results that suggest these formed through microbial iron oxidation. The GIF occurs in the Nconga Formation of the ca. 3.0-2.8 Ga Pongola Supergroup in South Africa and Swaziland. It is interbedded with oxide and silicate facies micritic iron formation (MIF). There is a strong textural control on iron mineralization in the GIF not observed in the associated MIF. The GIF is marked by oncoids with chert cores surrounded by magnetite and calcite rims. These rims show laminated domal textures, similar in appearance to microstromatolites. The GIF is enriched in silica and depleted in Fe relative to the interbedded MIF. Very low Al and trace element contents in the GIF indicate that chemically precipitated chert was reworked above wave base into granules in an environment devoid of siliciclastic input. Microbially mediated iron precipitation resulted in the formation of irregular, domal rims around the chert granules. During storm surges, oncoids were transported and deposited in deeper water environments. Textural features, along with positive δ56 Fe values in magnetite, suggest that iron precipitation occurred through incomplete oxidation of hydrothermal Fe2+ by iron-oxidizing bacteria. The initial Fe3+ -oxyhydroxide precipitates were then post-depositionally transformed to magnetite. Comparison of the Fe isotope compositions of the oncoidal GIF with those reported for the interbedded deeper water iron formation (IF) illustrates that the Fe2+ pathways and sources for these units were distinct. It is suggested that the deeper water IF was deposited from the evolved margin of a buoyant Fe2+aq -rich hydrothermal plume distal to its source. In contrast, oncolitic magnetite rims of chert granules were sourced from ambient Fe2+aq -depleted shallow ocean water beyond the plume.
Collapse
Affiliation(s)
- A J B Smith
- Paleoproterozoic Mineralization Research Group, Department of Geology, University of Johannesburg, Johannesburg, South Africa
- Department of Science and Technology - National Research Foundation Centre of Excellence for Integrated Mineral and Energy Resource Analysis, University of Johannesburg, Johannesburg, South Africa
- Department of Geology, University of Johannesburg, Johannesburg, South Africa
| | - N J Beukes
- Paleoproterozoic Mineralization Research Group, Department of Geology, University of Johannesburg, Johannesburg, South Africa
- Department of Science and Technology - National Research Foundation Centre of Excellence for Integrated Mineral and Energy Resource Analysis, University of Johannesburg, Johannesburg, South Africa
- Department of Geology, University of Johannesburg, Johannesburg, South Africa
| | - J Gutzmer
- Paleoproterozoic Mineralization Research Group, Department of Geology, University of Johannesburg, Johannesburg, South Africa
- Helmholtz Zentrum Dresden-Rossendorf, Helmholtz Institute Freiberg for Resource Technology, Freiberg, Germany
- Department of Mineralogy, TU Bergakademie Freiberg, Freiberg, Germany
| | - A D Czaja
- Department of Geology, University of Cincinnati, Cincinnati, OH, USA
- Department of Geoscience, University of Wisconsin, Madison, WI, USA
- NASA Astrobiology Institute, University of Wisconsin, Madison, WI, USA
| | - C M Johnson
- Department of Geoscience, University of Wisconsin, Madison, WI, USA
- NASA Astrobiology Institute, University of Wisconsin, Madison, WI, USA
| | - N Nhleko
- Paleoproterozoic Mineralization Research Group, Department of Geology, University of Johannesburg, Johannesburg, South Africa
- Geological Survey and Mines Department, Mbabane, Swaziland
| |
Collapse
|
21
|
Johnson CM, Kass PH, Cohen TA, Feldman EC. Effect of Intravenous or Perivascular Injection of Synthetic Adrenocorticotropic Hormone on Stimulation Test Results in Dogs. J Vet Intern Med 2017; 31:730-733. [PMID: 28407319 PMCID: PMC5435047 DOI: 10.1111/jvim.14708] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2016] [Revised: 02/22/2017] [Accepted: 03/02/2017] [Indexed: 11/28/2022] Open
Abstract
Background Standard protocols for adrenocorticotropic hormone (ACTH) stimulation testing (ACTHst) often involve intravenous (IV) injection of corticotropin. ACTH might be unintentionally injected into the perivascular (PV) space. Objective To compare stimulation test results after IV and PV injections of ACTH. Animals Twenty privately owned dogs were studied: 10 healthy and 10 with trilostane‐treated naturally occurring hyperadrenocorticism (HAC). Methods Prospective study. Each of 20 dogs underwent 2 ACTHst not <4 nor more than 14 days apart. Five healthy and 5 HAC dogs had an IV ACTHst first and PV second; 5 healthy and 5 HAC dogs had a PV ACTHst first and IV second. Blood samples for measurement of serum cortisol concentration were collected before and 1 hour after ACTH administration. Results No significant difference in results was demonstrated when comparing serum cortisol concentrations after IV and PV ACTH administration in all 20 dogs (median μg/dL; interval μg/dL: 8.2; 1.4–17.4 versus 7.8; 0.9–16.9; P = .23). No significant difference in results was demonstrated when comparing serum cortisol concentrations after IV and PV ACTH administration in the 10 healthy dogs (median μg/dL; interval μg/dL: 10.9; 7.3–17.4 versus 10.6; 7.1–16.9; P = .54) or in the 10 HAC dogs (median μg/dL; interval μg/dL: 6.3; 1.4–8.6 versus 5.2; 0.9–8.7; P = .061). Conclusions and Clinical Importance Perivascular administration of ACTH does not significantly alter stimulation test results in healthy dogs or in dogs with HAC undergoing therapy with trilostane.
Collapse
Affiliation(s)
- C M Johnson
- Department of Small Animal Internal Medicine, Animal Specialty and Emergency Center, Los Angeles, CA
| | - P H Kass
- Department of Population Health and Reproduction, School of Veterinary Medicine and School of Medicine, University of California, Davis, CA
| | - T A Cohen
- Department of Small Animal Internal Medicine, Animal Specialty and Emergency Center, Los Angeles, CA
| | - E C Feldman
- Department of Medicine and Epidemiology, School of Veterinary Medicine, University of California, Davis, CA
| |
Collapse
|
22
|
Besharat Z, Wakeham D, Johnson CM, Luengo GS, Greaves A, Odnevall Wallinder I, Göthelid M, Rutland MW. Mixed monolayers of alkane thiols with polar terminal group on gold: Investigation of structure dependent surface properties. J Colloid Interface Sci 2016; 484:279-290. [DOI: 10.1016/j.jcis.2016.08.053] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2016] [Revised: 08/19/2016] [Accepted: 08/19/2016] [Indexed: 10/21/2022]
|
23
|
Johnson CM, Gujral H, Wright KN, Munro EG. Basic Pelvic Anatomy. J Minim Invasive Gynecol 2016. [DOI: 10.1016/j.jmig.2016.08.435] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
|
24
|
Johnson CM, Gujral H, Wright KN. Teaching Laparoscopic Hysterectomy: Basic Anatomy and Surgical Steps. J Minim Invasive Gynecol 2016. [DOI: 10.1016/j.jmig.2016.08.330] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
|
25
|
Fortney NW, He S, Converse BJ, Beard BL, Johnson CM, Boyd ES, Roden EE. Microbial Fe(III) oxide reduction potential in Chocolate Pots hot spring, Yellowstone National Park. Geobiology 2016; 14:255-275. [PMID: 26750514 DOI: 10.1111/gbi.12173] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/29/2015] [Accepted: 11/10/2015] [Indexed: 06/05/2023]
Abstract
Chocolate Pots hot springs (CP) is a unique, circumneutral pH, iron-rich, geothermal feature in Yellowstone National Park. Prior research at CP has focused on photosynthetically driven Fe(II) oxidation as a model for mineralization of microbial mats and deposition of Archean banded iron formations. However, geochemical and stable Fe isotopic data have suggested that dissimilatory microbial iron reduction (DIR) may be active within CP deposits. In this study, the potential for microbial reduction of native CP Fe(III) oxides was investigated, using a combination of cultivation dependent and independent approaches, to assess the potential involvement of DIR in Fe redox cycling and associated stable Fe isotope fractionation in the CP hot springs. Endogenous microbial communities were able to reduce native CP Fe(III) oxides, as documented by most probable number enumerations and enrichment culture studies. Enrichment cultures demonstrated sustained DIR driven by oxidation of acetate, lactate, and H2 . Inhibitor studies and molecular analyses indicate that sulfate reduction did not contribute to observed rates of DIR in the enrichment cultures through abiotic reaction pathways. Enrichment cultures produced isotopically light Fe(II) during DIR relative to the bulk solid-phase Fe(III) oxides. Pyrosequencing of 16S rRNA genes from enrichment cultures showed dominant sequences closely affiliated with Geobacter metallireducens, a mesophilic Fe(III) oxide reducer. Shotgun metagenomic analysis of enrichment cultures confirmed the presence of a dominant G. metallireducens-like population and other less dominant populations from the phylum Ignavibacteriae, which appear to be capable of DIR. Gene (protein) searches revealed the presence of heat-shock proteins that may be involved in increased thermotolerance in the organisms present in the enrichments as well as porin-cytochrome complexes previously shown to be involved in extracellular electron transport. This analysis offers the first detailed insight into how DIR may impact the Fe geochemistry and isotope composition of a Fe-rich, circumneutral pH geothermal environment.
Collapse
Affiliation(s)
- N W Fortney
- Department of Geoscience, NASA Astrobiology Institute, University of Wisconsin-Madison, Madison, WI, USA
| | - S He
- Department of Geoscience, NASA Astrobiology Institute, University of Wisconsin-Madison, Madison, WI, USA
| | - B J Converse
- Department of Geoscience, NASA Astrobiology Institute, University of Wisconsin-Madison, Madison, WI, USA
| | - B L Beard
- Department of Geoscience, NASA Astrobiology Institute, University of Wisconsin-Madison, Madison, WI, USA
| | - C M Johnson
- Department of Geoscience, NASA Astrobiology Institute, University of Wisconsin-Madison, Madison, WI, USA
| | - E S Boyd
- Department of Microbiology and Immunology, NASA Astrobiology Institute, Montana State University, Bozeman, MT, USA
| | - E E Roden
- Department of Geoscience, NASA Astrobiology Institute, University of Wisconsin-Madison, Madison, WI, USA
| |
Collapse
|
26
|
Gustafsson E, Hedberg J, Larsson PA, Wågberg L, Johnson CM. Vibrational Sum Frequency Spectroscopy on Polyelectrolyte Multilayers: Effect of Molecular Surface Structure on Macroscopic Wetting Properties. Langmuir 2015; 31:4435-4442. [PMID: 25859709 DOI: 10.1021/la5046207] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Adsorption of a single layer of molecules on a surface, or even a reorientation of already present molecules, can significantly affect the surface properties of a material. In this study, vibrational sum frequency spectroscopy (VSFS) has been used to study the change in molecular structure at the solid-air interface following thermal curing of polyelectrolyte multilayers of poly(allylamine hydrochloride) and poly(acrylic acid). Significant changes in the VSF spectra were observed after curing. These changes were accompanied by a distinct increase in the static water contact angle, showing how the properties of the layer-by-layer molecular structure are controlled not just by the polyelectrolyte in the outermost layer but ultimately by the orientation of the chemical constituents in the outermost layers.
Collapse
Affiliation(s)
- Emil Gustafsson
- †KTH Royal Institute of Technology, School of Chemical Science and Engineering, Wallenberg Wood Science Center, Teknikringen 42, SE-100 44 Stockholm, Sweden
- ‡KTH Royal Institute of Technology, School of Chemical Science and Engineering, Department of Fibre and Polymer Technology, Teknikringen 56-58, SE-100 44 Stockholm, Sweden
| | - Jonas Hedberg
- §KTH Royal Institute of Technology, School of Chemical Science and Engineering, Division of Surface and Corrosion Science, Drottning Kristinas väg 51, SE-100 44 Stockholm, Sweden
| | - Per A Larsson
- ‡KTH Royal Institute of Technology, School of Chemical Science and Engineering, Department of Fibre and Polymer Technology, Teknikringen 56-58, SE-100 44 Stockholm, Sweden
| | - Lars Wågberg
- †KTH Royal Institute of Technology, School of Chemical Science and Engineering, Wallenberg Wood Science Center, Teknikringen 42, SE-100 44 Stockholm, Sweden
- ‡KTH Royal Institute of Technology, School of Chemical Science and Engineering, Department of Fibre and Polymer Technology, Teknikringen 56-58, SE-100 44 Stockholm, Sweden
| | - C Magnus Johnson
- §KTH Royal Institute of Technology, School of Chemical Science and Engineering, Division of Surface and Corrosion Science, Drottning Kristinas väg 51, SE-100 44 Stockholm, Sweden
| |
Collapse
|
27
|
Samuel-Hodge CD, Johnson CM, Braxton DF, Lackey M. Effectiveness of Diabetes Prevention Program translations among African Americans. Obes Rev 2014; 15 Suppl 4:107-24. [PMID: 25196409 DOI: 10.1111/obr.12211] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/10/2014] [Revised: 06/13/2014] [Accepted: 06/14/2014] [Indexed: 01/01/2023]
Abstract
The Diabetes Prevention Program (DPP) demonstrated risk reduction for incident diabetes through weight loss among all participants, including African Americans. Several DPP translations have been conducted in less controlled settings, including primary care practices and communities; however, there is no detailed compilation of how effective these translations have been for African Americans. This systematic literature review evaluated DPP translations from 2003 to 2012. Eligible records were retrieved using a search strategy of relevant databases and gray literature. Retrieved records (n=1,272) were screened using a priori criteria, which resulted in 21 full-text studies for review. Seventeen studies were included in the full-text qualitative synthesis. Seven studies had 100% African American samples and 10 studies had mixed samples with African American subgroups. African American participants' average weight loss was roughly half of that achieved in the DPP intervention. However, with few higher-quality studies, small sample sizes and differences in intervention designs and implementation, comparisons across interventions were difficult. The suboptimal effectiveness of DPP translations among African American adults, particularly women, signals the need for enhancements to existing evidence-based interventions and more high-quality research that includes other at-risk African American subgroups such as men and younger adults of lower socioeconomic status.
Collapse
Affiliation(s)
- C D Samuel-Hodge
- Department of Nutrition, University of North Carolina-Chapel Hill, Chapel Hill, NC, USA; Center for Health Promotion and Disease Prevention, University of North Carolina-Chapel Hill, NC, USA
| | | | | | | |
Collapse
|
28
|
Johnson CM, Baldelli S. Vibrational Sum Frequency Spectroscopy Studies of the Influence of Solutes and Phospholipids at Vapor/Water Interfaces Relevant to Biological and Environmental Systems. Chem Rev 2014; 114:8416-46. [DOI: 10.1021/cr4004902] [Citation(s) in RCA: 106] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Affiliation(s)
- C. Magnus Johnson
- Division of Surface and Corrosion
Science, Royal Institute of Technology (KTH), Drottning Kristinas Väg 51, SE-100 44 Stockholm, Sweden
| | - Steven Baldelli
- Department
of Chemistry, University of Houston, Texas 77204-5003, United States
| |
Collapse
|
29
|
Ghalgaoui A, Shimizu R, Hosseinpour S, Alvarez-Asencio R, McKee C, Johnson CM, Rutland MW. Monolayer study by VSFS: in situ response to compression and shear in a contact. Langmuir 2014; 30:3075-3085. [PMID: 24547702 DOI: 10.1021/la4042474] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Self-assembled octadecyltrichlorosilane ((OTS), CH3(CH2)17SiCl3) layers on hydroxyl-terminated silicon oxide (SiO2) were prepared. The monolayers were characterized with atomic force microscopy (AFM) and contact angle measurements; their conformation was studied before, during, and after contact with a polymer (either PDMS or PTFE) surface using the vibrational sum frequency spectroscopy (VSFS) technique. During contact, the effect of pressure was studied for both polymer surfaces, but in the case of PTFE, the effect of shear rate on the contact was simultaneously studied. The VSFS response of the monolayers with pressure was almost entirely due to changes in the real area of contact with the polymer and therefore the Fresnel factors, whereas sliding caused disorder in the previously all-trans monolayer, as evidenced by a significant increase in the population of gauche defects.
Collapse
Affiliation(s)
- Ahmed Ghalgaoui
- KTH Royal Institute of Technology , Division of Surface and Corrosion Science, Drottning Kristinas Väg 51, SE-100 44 Stockholm, Sweden
| | | | | | | | | | | | | |
Collapse
|
30
|
Liljeblad JFD, Tyrode E, Thormann E, Dublanchet AC, Luengo G, Magnus Johnson C, Rutland MW. Self-assembly of long chain fatty acids: effect of a methyl branch. Phys Chem Chem Phys 2014; 16:17869-82. [DOI: 10.1039/c4cp00512k] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The morphology and molecular conformation of monolayers of straight chain and methyl-branched fatty acids have been investigated by VSFS and AFM, revealing domains in the latter case, due to inverse micellar packing constraints.
Collapse
Affiliation(s)
- Jonathan F. D. Liljeblad
- School of Chemistry
- Division of Surface and Corrosion Science
- KTH Royal Institute of Technology
- SE-100 44 Stockholm, Sweden
| | - Eric Tyrode
- School of Chemistry
- Division of Surface and Corrosion Science
- KTH Royal Institute of Technology
- SE-100 44 Stockholm, Sweden
| | - Esben Thormann
- School of Chemistry
- Division of Surface and Corrosion Science
- KTH Royal Institute of Technology
- SE-100 44 Stockholm, Sweden
| | | | | | - C. Magnus Johnson
- School of Chemistry
- Division of Surface and Corrosion Science
- KTH Royal Institute of Technology
- SE-100 44 Stockholm, Sweden
| | - Mark W. Rutland
- School of Chemistry
- Division of Surface and Corrosion Science
- KTH Royal Institute of Technology
- SE-100 44 Stockholm, Sweden
- SP Technical Research Institute of Sweden
| |
Collapse
|
31
|
Schwind M, Hosseinpour S, Johnson CM, Langhammer C, Zorić I, Leygraf C, Kasemo B. Combined in situ quartz crystal microbalance with dissipation monitoring, indirect nanoplasmonic sensing, and vibrational sum frequency spectroscopic monitoring of alkanethiol-protected copper corrosion. Langmuir 2013; 29:7151-7161. [PMID: 23713406 DOI: 10.1021/la4009224] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
In this study, we have applied three techniques to simultaneously and in situ study the initial stage of corrosion of copper protected by a self-assembled monolayer of octadecanethiol (ODT). We combined quartz crystal microbalance with dissipation monitoring (QCM-D), indirect nanoplasmonic sensing (INPS), and vibrational sum frequency spectroscopy (VSFS) and obtained complementary information about mass uptake and optical and spectroscopic changes taking place during the initial corrosion phase. All three techniques are very sensitive to the formation of a corrosion film (thickness in the range 0-0.41 nm) under mildly corrosive conditions (dry air, <0.5% relative humidity). The three techniques yield information about the viscoelasticity of the corrosion film (QCM-D), the homogeneity of the corrosion reaction on the surface (INPS), and the stability of the ODT protection layer (VSFS). Furthermore, by also studying the corrosion process in humid air (ca. 70% relative humidity), we illustrate how the combination of these techniques can be used to differentiate between simultaneously occurring processes, such as water adsorption and corrosion product formation.
Collapse
Affiliation(s)
- Markus Schwind
- Department of Applied Physics, Chalmers University of Technology, Göteborg, Sweden.
| | | | | | | | | | | | | |
Collapse
|
32
|
Sharkey J, Johnson CM, Dean WR. Physical limitations in meal preparation and consumption are associated with lower musculoskeletal nutrient (calcium, vitamin D, magnesium, and phosphorus) intakes in homebound older adults. J Nutr Health Aging 2012; 16:675-7. [PMID: 23076508 DOI: 10.1007/s12603-012-0035-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
OBJECTIVES Although homebound older adults are at increased risk for poor nutritional health and adverse nutrition-related outcomes, little attention has focused on the tasks involved in meal preparation and consumption and the influence of those tasks on dietary intake. METHODS We examined the self-reported dietary intake from 3, 24-h dietary recalls and physical limitations in meal preparation and consumption (LMPC) activities from a randomly recruited sample of 345 homebound older men and women. Ordered logistic regression was used to examine the correlation of demographic characteristics and 6 activities with relative intakes of key musculoskeletal nutrients (calcium, vitamin D, magnesium, and phosphorus). RESULTS At least 70% reported not meeting ⅔ recommended intakes for calcium and vitamin D; 12.5% failed to achieve ⅔ recommended intakes in at least three of the four nutrients. More than 12% of the sample reported it was very difficult or they were unable to perform at least 3 LMPC tasks. Regression results indicated that reporting the greatest LMPC increased the odds for lower intake of musculoskeletal nutrients. CONCLUSION Independent of sociodemographic characteristics, self-reported difficulty in meal preparation and consumption was associated with lower dietary intakes of musculoskeletal nutrients. These results suggest the need to assess difficulty in meal preparation and consumption for the growing population of homebound older adults who participate in supplemental nutrition programs. This brief, 6-item measure may help identify older adults at risk of poor nutritional health and declining function.
Collapse
Affiliation(s)
- J Sharkey
- Texas Healthy Aging Research Network Collaborating Center, TX, USA.
| | | | | |
Collapse
|
33
|
Percak-Dennett EM, Beard BL, Xu H, Konishi H, Johnson CM, Roden EE. Iron isotope fractionation during microbial dissimilatory iron oxide reduction in simulated Archaean seawater. Geobiology 2011; 9:205-220. [PMID: 21504536 DOI: 10.1111/j.1472-4669.2011.00277.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
The largest Fe isotope excursion yet measured in marine sedimentary rocks occurs in shales, carbonates, and banded iron formations of Neoarchaean and Paleoproterozoic age. The results of field and laboratory studies suggest a potential role for microbial dissimilatory iron reduction (DIR) in producing this excursion. However, most experimental studies of Fe isotope fractionation during DIR have been conducted in simple geochemical systems, using pure Fe(III) oxide substrates that are not direct analogues to phases likely to have been present in Precambrian marine environments. In this study, Fe isotope fractionation was investigated during microbial reduction of an amorphous Fe(III) oxide-silica coprecipitate in anoxic, high-silica, low-sulphate artificial Archaean seawater at 30 °C to determine if such conditions alter the extent of reduction or isotopic fractionations relative to those observed in simple systems. The Fe(III)-Si coprecipitate was highly reducible (c. 80% reduction) in the presence of excess acetate. The coprecipitate did not undergo phase conversion (e.g. to green rust, magnetite or siderite) during reduction. Iron isotope fractionations suggest that rapid and near-complete isotope exchange took place among all Fe(II) and Fe(III) components, in contrast to previous work on goethite and hematite, where exchange was limited to the outer few atom layers of the substrate. Large quantities of low-δ(56)Fe Fe(II) (aqueous and solid phase) were produced during reduction of the Fe(III)-Si coprecipitate. These findings shed new light on DIR as a mechanism for producing Fe isotope variations observed in Neoarchaean and Paleoproterozoic marine sedimentary rocks.
Collapse
Affiliation(s)
- E M Percak-Dennett
- Department of Geoscience and NASA Astrobiology Institute, University of Wisconsin-Madison, WI, USA
| | | | | | | | | | | |
Collapse
|
34
|
Niga P, King W, Hedberg J, Johnson CM, Frey JG, Rutland MW. Crown ethers at the aqueous solution–air interface: 1. Assignments and surface spectroscopy. Phys Chem Chem Phys 2011; 13:7930-8. [DOI: 10.1039/c0cp00604a] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
|
35
|
Niga P, Johnson CM, Frey JG, Rutland MW. Crown ethers at the aqueous solution–air interface. Part 2. Electrolyte effects, ethylene oxide hydration and temperature behaviour. Phys Chem Chem Phys 2011; 13:7939-47. [DOI: 10.1039/c0cp02144j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
|
36
|
Tangalos GE, Beard BL, Johnson CM, Alpers CN, Shelobolina ES, Xu H, Konishi H, Roden EE. Microbial production of isotopically light iron(II) in a modern chemically precipitated sediment and implications for isotopic variations in ancient rocks. Geobiology 2010; 8:197-208. [PMID: 20374296 DOI: 10.1111/j.1472-4669.2010.00237.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
The inventories and Fe isotope composition of aqueous Fe(II) and solid-phase Fe compounds were quantified in neutral-pH, chemically precipitated sediments downstream of the Iron Mountain acid mine drainage site in northern California, USA. The sediments contain high concentrations of amorphous Fe(III) oxyhydroxides [Fe(III)(am)] that allow dissimilatory iron reduction (DIR) to predominate over Fe-S interactions in Fe redox transformation, as indicated by the very low abundance of Cr(II)-extractable reduced inorganic sulfur compared with dilute HCl-extractable Fe. delta(56)Fe values for bulk HCl- and HF-extractable Fe were approximately 0. These near-zero bulk delta(56)Fe values, together with the very low abundance of dissolved Fe in the overlying water column, suggest that the pyrite Fe source had near-zero delta(56)Fe values, and that complete oxidation of Fe(II) took place prior to deposition of the Fe(III) oxide-rich sediment. Sediment core analyses and incubation experiments demonstrated the production of millimolar quantities of isotopically light (delta(56)Fe approximately -1.5 to -0.5 per thousand) aqueous Fe(II) coupled to partial reduction of Fe(III)(am) by DIR. Trends in the Fe isotope composition of solid-associated Fe(II) and residual Fe(III)(am) are consistent with experiments with synthetic Fe(III) oxides, and collectively suggest an equilibrium Fe isotope fractionation between aqueous Fe(II) and Fe(III)(am) of approximately -2 per thousand. These Fe(III) oxide-rich sediments provide a model for early diagenetic processes that are likely to have taken place in Archean and Paleoproterozoic marine sediments that served as precursors for banded iron formations. Our results suggest pathways whereby DIR could have led to the formation of large quantities of low-delta(56)Fe minerals during BIF genesis.
Collapse
Affiliation(s)
- G E Tangalos
- Department of Geoscience and NASA Astrobiology Institute, University of Wisconsin, Madison, WI, USA
| | | | | | | | | | | | | | | |
Collapse
|
37
|
Liljeblad JF, Bulone V, Tyrode E, Rutland MW, Johnson CM. Phospholipid monolayers probed by vibrational sum frequency spectroscopy: instability of unsaturated phospholipids. Biophys J 2010; 98:L50-2. [PMID: 20483309 PMCID: PMC2872474 DOI: 10.1016/j.bpj.2010.02.009] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2009] [Revised: 01/27/2010] [Accepted: 02/12/2010] [Indexed: 11/29/2022] Open
Abstract
The surface specific technique vibrational sum frequency spectroscopy has been applied to in situ studies of the degradation of Langmuir monolayers of 1,2-diacyl-phosphocholines with various degrees of unsaturation in the aliphatic chains. To monitor the degradation of the phospholipids, the time-dependent change of the monolayer area at constant surface pressure and the sum frequency intensity of the vinyl CH stretch at the carbon-carbon double bonds were measured. The data show a rapid degradation of monolayers of phospholipids carrying unsaturated aliphatic chains compared to the stable lipids carrying fully saturated chains when exposed to the ambient laboratory air. In addition, the degradation of the phospholipids can be inhibited by purging the ambient air with nitrogen. This instability may be attributed to spontaneous degradation by oxidation mediated by various reactive species in the air. To further elucidate the process of lipid oxidation in biological membranes artificial Langmuir monolayers probed by a surface specific spectroscopic technique as in this study can serve as a model system for studying the degradation/oxidation of cell membrane constituents.
Collapse
Affiliation(s)
- Jonathan F.D. Liljeblad
- School of Chemistry, Division of Surface and Corrosion Science, Royal Institute of Technology, Stockholm, Sweden
| | - Vincent Bulone
- School of Biotechnology, Division of Glycoscience, Royal Institute of Technology, Stockholm, Sweden
| | - Eric Tyrode
- School of Chemistry, Division of Surface and Corrosion Science, Royal Institute of Technology, Stockholm, Sweden
| | - Mark W. Rutland
- School of Chemistry, Division of Surface and Corrosion Science, Royal Institute of Technology, Stockholm, Sweden
- Institute for Surface Chemistry, Stockholm, Sweden
| | - C. Magnus Johnson
- School of Chemistry, Division of Surface and Corrosion Science, Royal Institute of Technology, Stockholm, Sweden
| |
Collapse
|
38
|
Abstract
Anaplasma marginale has recently been shown to infect endothelial cells in vitro, but it remains unknown as to whether endothelial infection also occurs in vivo. In this report, we demonstrate through dual fluorescence microscopy that A marginale, detected by the monoclonal antibody ANAF16C1, co-localizes with the endothelial cell marker, von Willebrand factor, in tissue sections from an experimentally inoculated calf. The results indicate that A marginale infection includes endothelial cells and has implications for both pathogenesis and immune mechanisms.
Collapse
Affiliation(s)
- A D Carreño
- Department of Pathobiology, Auburn University, AL 36849-5519, USA
| | | | | | | | | | | |
Collapse
|
39
|
Johnson CM, Traherne JA, Jamieson SE, Tremelling M, Bingham S, Parkes M, Blackwell JM, Trowsdale J. Analysis of the BTNL2 truncating splice site mutation in tuberculosis, leprosy and Crohn's disease. ACTA ACUST UNITED AC 2007; 69:236-41. [PMID: 17493147 DOI: 10.1111/j.1399-0039.2006.00795.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The region on chromosome 6 encoding the major histocompatibility complex (MHC) is associated with a number of autoimmune and infectious diseases. Primary susceptibility to many of these has been localized to a region containing the human leukocyte antigen (HLA)-DR and -DQ genes. A recent study of sarcoidosis has provided evidence of an independent effect, associated with a truncating single nucleotide polymorphism (SNP) of a nearby gene, BTNL2. This gene may encode an immune receptor involved in costimulation. Sarcoidosis, tuberculoid leprosy, tuberculosis (TB) and Crohn's disease all have similar immunological features, including a Th1 response with granuloma formation. In addition mycobacteria have been identified or suggested to be causative pathogens in such conditions. We genotyped the truncating BTNL2 SNP in 92 TB and 72 leprosy families from Brazil and carried out family-based association studies. We could not find evidence of overtransmission of the truncating allele in TB. There was an association with susceptibility to leprosy (P=0.04), however, this is most likely due to linkage disequilibrium with HLA-DR. We also genotyped 476 UK Caucasian cases of Crohn's disease with 760 geographically matched controls and found no evidence of a disease association. We conclude that the truncating BTNL2 SNP is not important in this group of Th1 dominated granulomatous diseases.
Collapse
Affiliation(s)
- C M Johnson
- Cambridge Institute for Medical Research, Wellcome Trust/MRC Building, Addenbrooke's Hospital, Cambridge, UK
| | | | | | | | | | | | | | | |
Collapse
|
40
|
Abdulrahman M, Maina EN, Morris MR, Zatyka M, Raval RR, Banks RE, Wiesener MS, Richards FM, Johnson CM, Latif F, Maher ER. Identification of novel VHL targets that are associated with the development of renal cell carcinoma. Oncogene 2006; 26:1661-72. [PMID: 17001320 DOI: 10.1038/sj.onc.1209932] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
von Hippel-Lindau (VHL) disease is a dominantly inherited family cancer syndrome characterized by the development of retinal and central nervous system haemangioblastomas, renal cell carcinoma (RCC) and phaeochromocytoma. Specific germline VHL mutations may predispose to haemangioblastomas, RCC and phaeochromocytoma to a varying extent. Although dysregulation of the hypoxia-inducible transcription factor-2 and JunB have been linked to the development of RCC and phaeochromocytoma, respectively, the precise basis for genotype-phenotype correlations in VHL disease have not been defined. To gain insights into the pathogenesis of RCC in VHL disease we compared gene expression microarray profiles in a RCC cell line expressing a Type 1 or Type 2B mutant pVHL (RCC-associated) to those of a Type 2A or 2C mutant (not associated with RCC). We identified 19 differentially expressed novel VHL target genes linked to RCC development. Eight targets were studied in detail by quantitative real-time polymerase chain reaction (three downregulated and five upregulated by wild-type VHL) and for six genes the effect of VHL inactivation was mimicked by hypoxia (but hypoxic-induction of smooth muscle alpha-actin 2 was specific for a RCC cell line). The potential role of four RCC-associated VHL target genes was assessed in vitro. NB thymosin beta (TMSNB) and proteinase-activated receptor 2 (PAR2) (both downregulated by wt pVHL) increased cell growth and motility in a RCC cell line, but aldehyde dehydrogenase (ALDH)1 and ALDH7 had no effect. These findings implicate TMSNB and PAR2 candidate oncogenes in the pathogenesis of VHL-associated RCC.
Collapse
Affiliation(s)
- M Abdulrahman
- Department of Medical and Molecular Genetics, University of Birmingham, The Medical School, Birmingham, UK
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
41
|
Ripp S, Jegier P, Birmele M, Johnson CM, Daumer KA, Garland JL, Sayler GS. Linking bacteriophage infection to quorum sensing signalling and bioluminescent bioreporter monitoring for direct detection of bacterial agents. J Appl Microbiol 2006; 100:488-99. [PMID: 16478488 DOI: 10.1111/j.1365-2672.2005.02828.x] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
AIM To incorporate into the lambda phage genome, a luxI-based acyl-homoserine lactone (AHL) synthase genetic construct and exploit the autoamplified power of quorum sensing to translate a phage infection event into a chemical signature detectable by a lux-based bioluminescent bioreporter, with focus towards facile detection of microbial pathogens. METHODS AND RESULTS The luxI gene from Vibrio fischeri was inserted into the lambda phage genome to construct a model phage-based biosensor system for the general detection of Escherichia coli. The AHL signalling molecules synthesized upon phage infection are detected by an AHL-specific bioluminescent bioreporter based on the luxCDABE gene cassette of V. fischeri. The assay generates target-specific visible light signals with no requisite addition of extraneous substrate. This binary reporter system was able to autonomously respond to lambda phage infection events at target E. coli concentrations ranging from 1 x 10(8) to 1 CFU ml(-1) within 1.5-10.3 h, respectively, in pure culture. When assayed against artificially contaminated lettuce leaf washings, detection within an E. coli inoculum range from 1 x 10(8) to 130 CFU ml(-1) was achieved within 2.6-22.4 h, respectively. CONCLUSIONS The initial feasibility of binary phage-based reporter assays indicates that quorum sensing can be used to translate a phage infection event into an autoamplified chemical signature. SIGNIFICANCE AND IMPACT OF STUDY With further modification, binary phage-based reporter assays may be capable of rapidly and cost effectively detecting pathogenic agents at very low population densities.
Collapse
Affiliation(s)
- S Ripp
- Center for Environmental Biotechnology, University of Tennessee, Knoxville, TN 37996-1605, USA
| | | | | | | | | | | | | |
Collapse
|
42
|
Abstract
The splanchnic bed produces cortisol at rates approximating extraadrenal tissues by converting cortisone to cortisol via the 11beta-hydroxysteroid dehydrogenase (11beta-HSD) type 1 pathway. It is not known whether splanchnic cortisol production is regulated by nutrient ingestion and/or by the accompanying changes in hormone secretion. To address this question, 18 healthy humans were randomized to ingest either a mixed meal or to receive an intravenous saline infusion while total-body, splanchnic, and D3 cortisol production (an index of 11beta-HSD type 1 activity) were measured using the combined hepatic catheterization and D4 cortisol infusion methods. Fasting glucose and insulin concentrations did not differ on the meal and saline study days. Glucose and insulin concentrations increased after meal ingestion, peaking at 11.0 +/- 1.0 mmol/l and 451 +/- 64 pmol/l, respectively, at 45 min, then fell to baseline thereafter. In contrast, glucose and insulin concentrations slowly fell to 5.1 +/- 0.1 mmol/l and 27 +/- 6 pmol/l during the 6 h of observation on the saline study day. Fasting cortisol concentration did not differ on the meal and saline study days. Cortisol increased (P < 0.05) to a peak of 353 +/- 55 nmol/l after meal ingestion but did not change after saline infusion. The increase in cortisol after meal ingestion was associated with an increase in both total body cortisol (from 748 +/- 63 to 1,620 +/- 235 nmol/min; P < 0.01) and total body D3 cortisol (from 99 +/- 11 to 143 +/- 11 nmol/min; P < 0.01) production, whereas there was no change in either on the saline study day. The increase in total-body cortisol and D3 cortisol production after meal ingestion originated in extrasplanchnic tissues since splanchnic cortisol production (mean 0-360 min: 254 +/- 83 vs. 262 +/- 36 nmol/min) and splanchnic D3 cortisol production (mean 0-360 min: 72 +/- 22 vs. 77 +/- 14 nmol/min) did not differ on the meal and saline study days. We conclude that ingestion of a mixed meal does not alter either splanchnic cortisol production or the conversion of D4 cortisol to D3 cortisol or, therefore by implication, flux via the splanchnic 11beta-HSD type 1 pathway.
Collapse
Affiliation(s)
- Rita Basu
- Division of Endocrinology, Metabolism and Nutrition, Mayo Clinic, Rochester, MN 55905, USA
| | | | | | | | | |
Collapse
|
43
|
Nishida T, Johnson CM, Holman J, Osawa M, Davies PB, Ye S. Optical sum-frequency emission from langmuir-blodgett films of variable thickness: effects of the substrate and polar orientation of fatty acids in the films. Phys Rev Lett 2006; 96:077402. [PMID: 16606140 DOI: 10.1103/physrevlett.96.077402] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/14/2005] [Indexed: 05/08/2023]
Abstract
The nonlinear optical response arising from a model multilayer structure, i.e., Langmuir-Blodgett (LB) films comprised of different numbers of per-protonated (H) and per-deuterated (D) fatty acid layers on solid substrates, has been evaluated by sum-frequency generation (SFG) spectroscopy. The SFG signals depend significantly on the absolute polar orientation of the fatty acids in the individual layers and on the nonlinear optical response of the substrate. The SFG spectra on gold and fused quartz substrates demonstrate a totally different dependence on the number of the contributing H layers, which it is possible to analyze quantitatively. The results provide important information for understanding the origin of the nonlinear optical responses from ordered systems composed of multiple interfaces and therefore for extracting exact structural information about each interface from the observed SFG signals.
Collapse
Affiliation(s)
- Takuma Nishida
- Catalysis Research Center, Hokkaido University, Sapporo 001-0021, Japan
| | | | | | | | | | | |
Collapse
|
44
|
Sweat JM, Johnson CM, Marikar Y, Gibbs EP. Characterization of surface interleukin-2 receptor expression on gated populations of peripheral blood mononuclear cells from manatees, Trichechus manatus latirostris. Vet Immunol Immunopathol 2005; 108:269-83. [PMID: 16112745 DOI: 10.1016/j.vetimm.2005.06.006] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2004] [Revised: 04/19/2005] [Accepted: 06/01/2005] [Indexed: 11/23/2022]
Abstract
An in vitro system to determine surface interleukin-2 receptor (IL-2R) expression on mitogen-stimulated peripheral blood mononuclear cells (PBMC) from free-ranging manatees, Trichechus manatus latirostris was developed. Human recombinant IL-2, conjugated with a fluorescein dye was used in conjunction with flow cytometric analysis to determine changes in surface expression of IL-2R at sequential times over a 48-h period of in vitro stimulation. Surface expression of IL-2R was detected on manatee PBMC, which also cross-reacted with an anti-feline pan T-cell marker. An expression index (EI) was calculated by comparing mitogen-activated and non-activated PBMC. Based on side- and forward-scatter properties, flow cytometric analysis showed an increase in the number of larger, more granular "lymphoblasts" following concanavalin A (Con A) stimulation. The appearance of lymphoblasts was correlated with an increase in their surface expression of IL-2 receptors. Surface IL-2R expression, in Con A-stimulated PBMC, was detected at 16 h, peaked at 24-36 h, and began to decrease by 48 h. Characterization of the IL-2R expression should provide additional information on the health status of manatees, and the effect of their sub lethal exposure to brevetoxin.
Collapse
Affiliation(s)
- J M Sweat
- University of Florida, College of Veterinary Medicine, Department of Pathobiology, P.O. Box 110880, Gainesville, FL 32611, USA.
| | | | | | | |
Collapse
|
45
|
Tyrode E, Johnson CM, Kumpulainen A, Rutland MW, Claesson PM. Hydration State of Nonionic Surfactant Monolayers at the Liquid/Vapor Interface: Structure Determination by Vibrational Sum Frequency Spectroscopy. J Am Chem Soc 2005; 127:16848-59. [PMID: 16316231 DOI: 10.1021/ja053289z] [Citation(s) in RCA: 94] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The OH stretching region of water molecules in the vicinity of nonionic surfactant monolayers has been investigated using vibrational sum frequency spectroscopy (VSFS) under the polarization combinations ssp, ppp, and sps. The surface sensitivity of the VSFS technique has allowed targeting the few water molecules present at the surface with a net orientation and, in particular, the hydration shell around alcohol, sugar, and poly(ethylene oxide) headgroups. Dramatic differences in the hydration shell of the uncharged headgroups were observed, both in comparison to each another and in comparison to the pure water surface. The water molecules around the rigid glucoside and maltoside sugar rings were found to form strong hydrogen bonds, similar to those observed in tetrahedrally coordinated water in ice. In the case of the poly(ethylene oxide) surfactant monolayer a significant ordering of both strongly and weakly hydrogen bonded water was observed. Moreover, a band common to all the surfactants studied, clearly detected at relatively high frequencies in the polarization combinations ppp and sps, was assigned to water species located in proximity to the surfactant hydrocarbon tail phase, with both hydrogen atoms free from hydrogen bonds. An orientational analysis provided additional information on the water species responsible for this band.
Collapse
Affiliation(s)
- Eric Tyrode
- Department of Chemistry, Surface Chemistry, Royal Institute of Technology, Stockholm, Sweden
| | | | | | | | | |
Collapse
|
46
|
Caporale DA, Johnson CM, Millard BJ. Presence of Borrelia burgdorferi (Spirochaetales: Spirochaetaceae) in southern Kettle Moraine State Forest, Wisconsin, and characterization of strain W97F51. J Med Entomol 2005; 42:457-72. [PMID: 15962800 DOI: 10.1093/jmedent/42.3.457] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Lyme disease, caused by Borrelia burgdorferi Johnson, Schmidt, Hyde, Steigerwalt & Brenner; babesiosis, caused by Babesia microti Franca; and human granulocytic ehrlichiosis, caused by Anaplasma phagocytophilum Bakken & Dumler have been reported in Wisconsin, mainly in the endemic areas of the northwestern part of the state. People exposed to blacklegged ticks, Ixodes scapularis Say, from this region can potentially contract one or all of these diseases concurrently. Within the past several years, there have been cases of Lyme disease reported from southeastern Wisconsin, an area that contains deer, mice, and similar vegetation found at regions with high endemicity. However, past white-tailed deer surveys suggested no existence of I. scapularis in southeastern Wisconsin. However, in 1996, we identified questing adult I. scapularis in the southernmost part of the Southern Kettle Moraine State Forest, Walworth County. To determine whether an established population of I. scapularis exists in this region, we performed a detailed survey of the abundance of host-seeking I. scapularis adults and the presence and abundance of subadults feeding on white-footed mice, Peromyscus leucopus Rafinesque. We also tested for possible infections of B. burgdorferi, Ba. microti, and A. phagocytophilum in ticks and B. burgdorferi harbored by mice. In 1997 and 1998, a total of 249 P. leucopus mice and 118 questing adult I. scapularis ticks, in addition to 157 larvae and seven nymphs feeding on mice, were collected and their locations were recorded from the Nordic trails of the Southern Kettle Moraine State Forest. Only one P. leucopus and its attached engorged I. scapularis nymph were infected with B. burgdorferi, whereas none of the engorged larvae attached to mice were infected. However, 4.2% of questing adult I. scapularis were infected with B. burgdorferi. The abundance of questing adult I. scapularis was 1.6 ticks per hour. The prevalence of subadult ticks on mice was 27%, with a mean intensity on infested mice of 2.0. I. scapularis adults were not infected with either Ba. microti or A. phagocytophilum. A unique strain of B. burgdorferi s.l. (W97F51) was discovered, showing 33 nucleotide substitutions and one codon insertion in a 567-bp fragment of the OspB gene, compared with Borrelia bissettii (strain Ca389). The sequences of ospA, ospB, ospC,fla, and rrs genes and the rrf-rrl intergenic spacer region were compared between W97F51 and other B. burgdorferi s.l. species. Although W97F51 was most genetically related to B. bissettii, the genetic identity of W97F51 was less than that of B. bissettii conspecifics. This study documents the existence of an established population of I. scapularis and the presence of B. burgdorferi with a novel strain in southeastern Wisconsin.
Collapse
Affiliation(s)
- D A Caporale
- Department of Biology, University of Wisconsin-Stevens Point, Stevens Point, WI 54481, USA
| | | | | |
Collapse
|
47
|
Lawoko-Kerali G, Milo M, Davies D, Halsall A, Helyer R, Johnson CM, Rivolta MN, Tones MA, Holley MC. Ventral otic cell lines as developmental models of auditory epithelial and neural precursors. Dev Dyn 2005; 231:801-14. [PMID: 15499550 DOI: 10.1002/dvdy.20187] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Conditionally immortal cell lines were established from the ventral otocyst of the Immortomouse at embryonic day 10.5 and selected to represent precursors of auditory sensory neural and epithelial cells. Selection was based upon dissection, tissue-specific markers, and expression of the transcription factor GATA3. Two cell lines expressed GATA3 but possessed intrinsically different genetic programs under differentiating conditions. US/VOT-E36 represented epithelial progenitors with potential to differentiate into sensory and nonsensory epithelial cells. US/VOT-N33 represented migrating neuroblasts. Under differentiating conditions in vitro the cell lines expressed very different gene expression profiles. Expression of several cell- and tissue-specific markers, including the transcription factors Pax2, GATA3, and NeuroD, differed between the cell lines in a pattern consistent with that observed between their counterparts in vivo. We suggest that these and other conditionally immortal cell lines can be used to study transient events in development against different backgrounds of cell competence.
Collapse
Affiliation(s)
- G Lawoko-Kerali
- Department of Biomedical Sciences, Addison Building, Western Bank, Sheffield, United Kingdom
| | | | | | | | | | | | | | | | | |
Collapse
|
48
|
Kumpulainen AJ, Persson CM, Eriksson JC, Tyrode EC, Johnson CM. Soluble monolayers of n-decyl glucopyranoside and n-decyl maltopyranoside. Phase changes in the gaseous to the liquid-expanded range. Langmuir 2005; 21:305-315. [PMID: 15620319 DOI: 10.1021/la047791t] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
To examine the transition from the gaseous to the liquid-expanded monolayer state, surface tension data were recorded for n-decyl beta-d-glucopyranoside (Glu) and n-decyl beta-d-maltopyranoside (Mal) solutions at low concentrations and at different temperatures. Comparisons were also made with n-decyl beta-d-thiomaltopyranoside (S-Mal) solutions at room temperature. The transitions observed occur at very low concentrations and surface pressures, about 0.5% of the critical micelle concentration (cmc) and between 0.8 and 1 mN/m for Glu and Mal at 22 degrees C. For S-Mal the transition is recorded for a concentration of 0.5% of the cmc as well, but the surface pressure is lower, about 0.4 mN/m. The gradual change in molecular area about the transition is from about 500 to 200 A(2) and 400 to 150 A(2) for Mal and Glu, respectively, and from about 800 to 250 A(2) for S-Mal. The comparatively large molecular areas after the transitions are incompatible with the notion that a coherent hydrocarbon film would cover the entire surface already at this stage. Standard surface thermodynamics was applied to elucidate the nature of these transitions in combination with two model concepts: The formation of an infinite network of surfactant molecules and, second, the formation of surface micelles. Hard-disk simulation results were employed to quantify the additional surface pressure after the transition attributed to the formation of surface micelles. In conclusion the formation of surface micelles is plausible as the hard-disk model is capable of accounting for the additional surface pressure increase with acceptable accuracy. Further, vibrational sum frequency spectroscopy was used to investigate the transition for Mal. Using the distinct feature of the non-hydrogen-bonded OH ("free OH") at 3700 cm(-)(1) for probing the surface water state, it could be determined that the surface holds a sizable fraction of unperturbed surface water even after the transition from the Henry range. The decrease in the free OH signal was found to correlate with the increase in surface density of surface micelles.
Collapse
Affiliation(s)
- Atte J Kumpulainen
- Department of Chemistry, Surface Chemistry, Royal Institute of Technology, SE-100 44 Stockholm, Sweden.
| | | | | | | | | |
Collapse
|
49
|
Johnson CM, Tyrode E. Study of the adsorption of sodium dodecyl sulfate (SDS) at the air/water interface: targeting the sulfate headgroup using vibrational sum frequency spectroscopy. Phys Chem Chem Phys 2005; 7:2635-40. [PMID: 16189575 DOI: 10.1039/b505219j] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The surface sensitive technique vibrational sum frequency spectroscopy (VSFS), has been used to study the adsorption behaviour of SDS to the liquid/vapour interface of aqueous solutions, specifically targeting the sulfate headgroup stretches. In the spectral region extending from 980 to 1850 cm(-1), only the vibrations due to the SO(3) group were detectable. The fitted amplitudes for the symmetric SO(3) stretch observed at 1070 cm(-1) for the polarization combinations ssp and ppp, were seen to follow the adsorption isotherm calculated from surface tension measurements. The orientation of the sulfate headgroup in the concentration range spanning from 1.0 mM to above the critical micellar concentration (c.m.c.) was observed to remain constant within experimental error, with the pseudo-C(3) axis close to the surface normal. Furthermore, the effect of increasing amounts of sodium chloride at SDS concentrations above c.m.c. was also studied, showing an increase of approximately 12% in the fitted amplitude for the symmetric SO(3) stretch when increasing the ionic strength from 0 to 300 mM NaCl. Interestingly, the orientation of the SDS headgroup was also observed to remain constant within this concentration range and identical to the case without NaCl.
Collapse
Affiliation(s)
- C Magnus Johnson
- Division of Corrosion Science, Royal Institute of Technology, Drottning Kristinas Väg 51, SE-100 44 Stockholm, Sweden
| | | |
Collapse
|
50
|
Johnson CM, Tyrode E, Baldelli S, Rutland MW, Leygraf C. A Vibrational Sum Frequency Spectroscopy Study of the Liquid−Gas Interface of Acetic Acid−Water Mixtures: 1. Surface Speciation. J Phys Chem B 2004; 109:321-8. [PMID: 16851018 DOI: 10.1021/jp047338q] [Citation(s) in RCA: 85] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Aqueous acetic acid solutions have been studied by vibrational sum frequency spectroscopy (VSFS) in order to acquire molecular information about the liquid-gas interface. The concentration range 0-100% acetic acid has been studied in the CH/OH and the C-O/C=O regions, and in order to clarify peak assignments, experiments with deuterated acetic acid and water have also been performed. Throughout the whole concentration range, the acetic acid is proven to be protonated. It is explicitly shown that the structure of a water surface becomes disrupted even at small additions of acetic acid. Furthermore, the spectral evolution upon increasing the concentration of acetic acid is explained in terms of the different complexes of acetic acid molecules, such as the hydrated monomer, linear dimer, and cyclic dimer. In the C=O region, the hydrated monomer is concluded to give rise to the sum frequency (SF) signal, and in the CH region, the cyclic dimer contributes to the signal as well. The combination of results from the CH/OH and the C-O/C=O regions allows a thorough characterization of the behavior of the acetic acid molecules at the interface to be obtained.
Collapse
Affiliation(s)
- C Magnus Johnson
- Division of Corrosion Science, Royal Institute of Technology, Drottning Kristinas Väg 51, SE-100 44 Stockholm, Sweden
| | | | | | | | | |
Collapse
|