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Farfan GA, McKeown DA, Post JE. Mineralogical characterization of biosilicas versus geological analogs. GEOBIOLOGY 2023; 21:520-533. [PMID: 36849877 DOI: 10.1111/gbi.12553] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/26/2022] [Revised: 01/30/2023] [Accepted: 02/12/2023] [Indexed: 06/13/2023]
Abstract
Non-crystalline silica mineraloids are essential to life on Earth as they provide architectural structure to dominant primary producers, such as plants and phytoplankton, as well as to protists and sponges. Due to the difficulty in characterizing and quantifying the structure of highly disordered X-ray amorphous silica, relatively little has been done to understand the mineralogy of biogenic silica and how this may impact the material properties of biogenic silica, such as hardness and strength, or how biosilica might be identified and differentiated from its inorganic geological counterparts. Typically, geologically formed opal-A and hyalite opal-AN are regarded as analogs to biogenic silica, however, some spectroscopic and imaging studies suggest that this might not be a reasonable assumption. In this study, we use a variety of techniques (X-ray diffraction, Raman spectroscopy, and scanning electron microscopy) to compare differences in structural disorder and bonding environments of geologically formed hydrous silicas (Opal-A, hyalite, geyserite) and silica glass versus biogenic silicas from an array of organisms. Our results indicate differences in the levels of structural disorder and the Raman-observed bonding environments of the SiO2 network modes (D1 mode) and the Q-species modes (~1015 cm-1 ) between varieties of biogenic silicas and geologically formed silicas, which aligns with previous studies that suggest fundamental differences between biogenic and geologically formed silica. Biosilicas also differ structurally from one another by species of organism. Our mineralogical approach to characterizing biosilicas and differentiating them from other silicas may be expanded to future diagenesis studies, and potentially applied to astrobiology studies of Earth and other planets.
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Affiliation(s)
- Gabriela A Farfan
- Department of Mineral Sciences, National Museum of Natural History, Smithsonian Institution, Washington, District of Columbia, USA
| | - David A McKeown
- Vitreous State Laboratory, The Catholic University of America, Washington, District of Columbia, USA
| | - Jeffrey E Post
- Department of Mineral Sciences, National Museum of Natural History, Smithsonian Institution, Washington, District of Columbia, USA
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2
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Novel Approach to Freshwater Diatom Profiling and Identification Using Raman Spectroscopy and Chemometric Analysis. WATER 2022. [DOI: 10.3390/w14132116] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
(1) An approach with great potential for fast and cost-effective profiling and identification of diatoms in lake ecosystems is presented herein. This approach takes advantage of Raman spectroscopy. (2) The study was based on the analysis of 790 Raman spectra from 29 species, belonging to 15 genera, 12 families, 9 orders and 4 subclasses, which were analysed using chemometric methods. The Raman data were first analysed by a partial least squares regression discriminant analysis (PLS-DA) to characterise the diatom species. Furthermore, a method was developed to streamline the integrated interpretation of PLS-DA when a high number of significant components is extracted. Subsequently, an artificial neural network (ANN) was used for taxa identification from Raman data. (3) The PLS interpretation produced a Raman profile for each species reflecting its biochemical composition. The ANN models were useful to identify various taxa with high accuracy. (4) Compared to studies in the literature, involving huge datasets one to four orders of magnitude larger than ours, high sensitivity was found for the identification of Achnanthidium exiguum (67%), Fragilaria pararumpens (67%), Amphora pediculus (71%), Achnanthidium minutissimum (80%) and Melosira varians (82%).
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3
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Owari Y, Nakamura F, Oaki Y, Tsuda H, Shimode S, Imai H. Ultrastructure of setae of a planktonic diatom, Chaetoceros coarctatus. Sci Rep 2022; 12:7568. [PMID: 35534511 PMCID: PMC9085750 DOI: 10.1038/s41598-022-11484-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2021] [Accepted: 04/25/2022] [Indexed: 11/20/2022] Open
Abstract
Silica frustules of most planktonic diatoms have many shallow holes in which the length (L) is smaller than the width (W). The present study focuses on a silica ultrastructure of setae of a planktonic diatom having deep (L/W > 1) holes. Here, we characterized microscopically patterned nanoholes on the silica walls of thick, robust, and hollow setae of a colony of Chaetoceros coarctatus. Basically, tetragonal poroid arrangements with and without a costa pattern are observed on the inner and outer surfaces, respectively, for three kinds of curving hollow setae attached to the anterior, intercalary, and posterior parts of the colony. The seta structures including specific poroid arrangements and continuity of deep nanoholes depend on the location. The deep nanoholes ∼90 nm wide are elongated from 150 to 1500 nm (L/W ∼17) with an increase in the wall thickness of the polygonal tubes of the setae. The inside poroid array, with a period of 190 nm in the extension direction of setae, is lined by parallel plates of the costae. However, the poroid arrangement on the outer surface is disordered, with several holes obstructed with increasing wall thickness of the posterior terminal setae. According to the movement of a colony in a fluid microchannel, the thick curving terminal setae is suggested to involve attitude control and mechanical protection. Using an optical simulation, the patterned deep through-holes on the intercalary setae were suggested to contribute anti-reflection of blue light in the wavelength range of 400 to 500 nm for the promotion of photosynthesis in seawater.
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Affiliation(s)
- Yuka Owari
- School of Integrated Design Engineering, Faculty of Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama, 223-8522, Japan
| | - Fumi Nakamura
- School of Integrated Design Engineering, Faculty of Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama, 223-8522, Japan
| | - Yuya Oaki
- School of Integrated Design Engineering, Faculty of Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama, 223-8522, Japan
| | - Hiroyuki Tsuda
- School of Integrated Design Engineering, Faculty of Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama, 223-8522, Japan
| | - Shinji Shimode
- Manazuru Marine Center for Environmental Research and Education, Graduate School of Environment and Information Sciences, Yokohama National University, 61 Iwa, Manazuru, 259-0202, Japan
| | - Hiroaki Imai
- School of Integrated Design Engineering, Faculty of Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama, 223-8522, Japan.
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Supiyani, Agusnar H, Sugita P, Nainggolan I. Preparation sodium silicate from rice husk to synthesize silica nanoparticles by sol-gel method for adsorption water in analysis of methamphetamine. SOUTH AFRICAN JOURNAL OF CHEMICAL ENGINEERING 2022. [DOI: 10.1016/j.sajce.2022.02.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
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5
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Oliva-Teles L, Pinto R, Vilarinho R, Carvalho AP, Moreira JA, Guimarães L. Environmental diagnosis with Raman Spectroscopy applied to diatoms. Biosens Bioelectron 2022; 198:113800. [PMID: 34838373 DOI: 10.1016/j.bios.2021.113800] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2021] [Revised: 10/04/2021] [Accepted: 11/12/2021] [Indexed: 12/30/2022]
Abstract
Freshwater quality has been changing due to the ever greater use of water resources and the contamination load resulting from human activities. Management of these systems, thus, requires constant diagnose of water quality with fast and efficient methodologies. The conventional methods adopted are, however, time-consuming, often very expensive, and require specialised expertise. Raman spectroscopy (RS) is a simple, fast and label-free technique that can be applied to environmental diagnosis using diatoms. Here, we developed a diagnostic method based on Raman spectroscopy applied to freshwater diatoms. For this, Raman spectra were recorded from diatoms of three lakes of a natural city park. The data acquired was analysed by chemometrics methods to describe the data (Partial Least Squares Regression), infer relationships in the dataset (Cluster Analysis) and produce classification models (Artificial Neural Network). The classification models developed diagnosed the lakes with excellent accuracy (89%) without requiring taxonomic information about the diatom species recorded. This study provides a proof-of-concept for the application of diatom Raman spectroscopy to diagnosing water quality, laying an important foundation for future environmental studies aiming at assessing freshwater systems, to be replicated at larger scales and to varied geographic settings.
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Affiliation(s)
- Luís Oliva-Teles
- CIIMAR/CIMAR, Interdisciplinary Centre of Marine and Environmental Research, University of Porto, Terminal de Cruzeiros Do Porto de Leixões, Avenida General Norton de Matos, s/n, 4450-208, Matosinhos, Portugal; Department of Biology, Faculty of Sciences of the University of Porto, Rua Do Campo Alegre, s/n, 4169-007, Porto, Portugal.
| | - Raquel Pinto
- CIIMAR/CIMAR, Interdisciplinary Centre of Marine and Environmental Research, University of Porto, Terminal de Cruzeiros Do Porto de Leixões, Avenida General Norton de Matos, s/n, 4450-208, Matosinhos, Portugal; Department of Biology, Faculty of Sciences of the University of Porto, Rua Do Campo Alegre, s/n, 4169-007, Porto, Portugal
| | - Rui Vilarinho
- IFIMUP, Department of Physics and Astronomy, Faculty of Sciences of the University of Porto, Rua Do Campo Alegre, s/n, 4169-007, Porto, Portugal
| | - António Paulo Carvalho
- CIIMAR/CIMAR, Interdisciplinary Centre of Marine and Environmental Research, University of Porto, Terminal de Cruzeiros Do Porto de Leixões, Avenida General Norton de Matos, s/n, 4450-208, Matosinhos, Portugal; Department of Biology, Faculty of Sciences of the University of Porto, Rua Do Campo Alegre, s/n, 4169-007, Porto, Portugal
| | - J Agostinho Moreira
- IFIMUP, Department of Physics and Astronomy, Faculty of Sciences of the University of Porto, Rua Do Campo Alegre, s/n, 4169-007, Porto, Portugal
| | - Laura Guimarães
- CIIMAR/CIMAR, Interdisciplinary Centre of Marine and Environmental Research, University of Porto, Terminal de Cruzeiros Do Porto de Leixões, Avenida General Norton de Matos, s/n, 4450-208, Matosinhos, Portugal; Department of Biology, Faculty of Sciences of the University of Porto, Rua Do Campo Alegre, s/n, 4169-007, Porto, Portugal
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Pinto R, Vilarinho R, Carvalho AP, Moreira JA, Guimarães L, Oliva-Teles L. Raman spectroscopy applied to diatoms (microalgae, Bacillariophyta): Prospective use in the environmental diagnosis of freshwater ecosystems. WATER RESEARCH 2021; 198:117102. [PMID: 33882320 DOI: 10.1016/j.watres.2021.117102] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/16/2020] [Revised: 03/28/2021] [Accepted: 03/29/2021] [Indexed: 06/12/2023]
Abstract
Diatom species are good pollution bioindicators due to their large distribution, fast response to changes in environmental parameters and different tolerance ranges. These organisms are used in ecological water assessment all over the world using autoecological indices. Such assessments commonly rely on the taxonomic identification of diatom species-specific shape and frustule ornaments, from which cell counts, species richness and diversity indices can be estimated. Taxonomic identification is, however, time-consuming and requires years of expertise. Additionally, though the diatom autoecological indices are region-specific, they are often applied indiscriminately across regions. Raman spectroscopy is a simpler, fast and label-free technique that can be applied to environmental diagnosis with diatoms. However, this approach has been poorly explored. This work reviews Raman spectroscopy studies involving the structure, location and conformation of diatom cell components and their variation under different conditions. A critical appreciation of the pros and cons of its application to environmental diagnosis is also given. This knowledge provides a strong foundation for the development of environmental protocols using Raman spectroscopy in diatoms. Our work aims at stimulating further research on the application of Raman spectroscopy as a tool to assess physiological changes and water quality under a changing climate.
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Affiliation(s)
- Raquel Pinto
- CIIMAR/CIMAR - Interdisciplinary Centre of Marine and Environmental Research, University of Porto, Terminal de Cruzeiros do Porto de Leixões, Avenida General Norton de Matos, s/n 4450-208 Matosinhos, Portugal; Department of Biology, Faculty of Sciences of the University of Porto, Rua do Campo Alegre, s/n, 4169-007, Porto, Portugal
| | - Rui Vilarinho
- IFIMUP, Department of Physics and Astronomy, Faculty of Sciences of the University of Porto, Rua do Campo Alegre, s/n. 4169-007, Porto, Portugal
| | - António Paulo Carvalho
- CIIMAR/CIMAR - Interdisciplinary Centre of Marine and Environmental Research, University of Porto, Terminal de Cruzeiros do Porto de Leixões, Avenida General Norton de Matos, s/n 4450-208 Matosinhos, Portugal; Department of Biology, Faculty of Sciences of the University of Porto, Rua do Campo Alegre, s/n, 4169-007, Porto, Portugal
| | - J Agostinho Moreira
- IFIMUP, Department of Physics and Astronomy, Faculty of Sciences of the University of Porto, Rua do Campo Alegre, s/n. 4169-007, Porto, Portugal
| | - Laura Guimarães
- CIIMAR/CIMAR - Interdisciplinary Centre of Marine and Environmental Research, University of Porto, Terminal de Cruzeiros do Porto de Leixões, Avenida General Norton de Matos, s/n 4450-208 Matosinhos, Portugal; Department of Biology, Faculty of Sciences of the University of Porto, Rua do Campo Alegre, s/n, 4169-007, Porto, Portugal.
| | - Luís Oliva-Teles
- CIIMAR/CIMAR - Interdisciplinary Centre of Marine and Environmental Research, University of Porto, Terminal de Cruzeiros do Porto de Leixões, Avenida General Norton de Matos, s/n 4450-208 Matosinhos, Portugal; Department of Biology, Faculty of Sciences of the University of Porto, Rua do Campo Alegre, s/n, 4169-007, Porto, Portugal.
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Kahle EM, Zarnkow M, Jacob F. Beer Turbidity Part 2: A Review of Raman Spectroscopy and Possible Future Use for Beer Turbidity Analysis. JOURNAL OF THE AMERICAN SOCIETY OF BREWING CHEMISTS 2020. [DOI: 10.1080/03610470.2020.1800345] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Affiliation(s)
- Eva-Maria Kahle
- Forschungszentrum Weihenstephan für Brau- und Lebensmittelqualität, Technische Universität München, Alte Akademie 3, 85354 Freising-Weihenstephan, Germany
| | - Martin Zarnkow
- Forschungszentrum Weihenstephan für Brau- und Lebensmittelqualität, Technische Universität München, Alte Akademie 3, 85354 Freising-Weihenstephan, Germany
| | - Fritz Jacob
- Forschungszentrum Weihenstephan für Brau- und Lebensmittelqualität, Technische Universität München, Alte Akademie 3, 85354 Freising-Weihenstephan, Germany
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8
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Nowak AP, Sprynskyy M, Wojtczak I, Trzciński K, Wysocka J, Szkoda M, Buszewski B, Lisowska-Oleksiak A. Diatoms Biomass as a Joint Source of Biosilica and Carbon for Lithium-Ion Battery Anodes. MATERIALS (BASEL, SWITZERLAND) 2020; 13:E1673. [PMID: 32260175 PMCID: PMC7178308 DOI: 10.3390/ma13071673] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/17/2020] [Revised: 03/26/2020] [Accepted: 03/27/2020] [Indexed: 11/16/2022]
Abstract
The biomass of one type cultivated diatoms (Pseudostaurosira trainorii), being a source of 3D-stuctured biosilica and organic matter-the source of carbon, was thermally processed to become an electroactive material in a potential range adequate to become an anode in lithium ion batteries. Carbonized material was characterized by means of selected solid-state physics techniques (XRD, Raman, TGA). It was shown that the pyrolysis temperature (600 °C, 800 °C, 1000 °C) affected structural and electrochemical properties of the electrode material. Biomass carbonized at 600 °C exhibited the best electrochemical properties reaching a specific discharge capacity of 460 mAh g-1 for the 70th cycle. Such a value indicates the possibility of usage of biosilica as an electrode material in energy storage applications.
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Affiliation(s)
- Andrzej P. Nowak
- Chemical Faculty, Gdańsk University of Technology, Narutowicza 11/12, 80-233 Gdańsk, Poland; (K.T.); (J.W.); (M.S.)
| | - Myroslav Sprynskyy
- Faculty of Chemistry, Nicolaus Copernicus University, Gagarina 11, 87-100 Toruń, Poland; (M.S.); (I.W.); (B.B.)
| | - Izabela Wojtczak
- Faculty of Chemistry, Nicolaus Copernicus University, Gagarina 11, 87-100 Toruń, Poland; (M.S.); (I.W.); (B.B.)
| | - Konrad Trzciński
- Chemical Faculty, Gdańsk University of Technology, Narutowicza 11/12, 80-233 Gdańsk, Poland; (K.T.); (J.W.); (M.S.)
| | - Joanna Wysocka
- Chemical Faculty, Gdańsk University of Technology, Narutowicza 11/12, 80-233 Gdańsk, Poland; (K.T.); (J.W.); (M.S.)
| | - Mariusz Szkoda
- Chemical Faculty, Gdańsk University of Technology, Narutowicza 11/12, 80-233 Gdańsk, Poland; (K.T.); (J.W.); (M.S.)
| | - Bogusław Buszewski
- Faculty of Chemistry, Nicolaus Copernicus University, Gagarina 11, 87-100 Toruń, Poland; (M.S.); (I.W.); (B.B.)
| | - Anna Lisowska-Oleksiak
- Chemical Faculty, Gdańsk University of Technology, Narutowicza 11/12, 80-233 Gdańsk, Poland; (K.T.); (J.W.); (M.S.)
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9
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Laviale M, Beaussart A, Allen J, Quilès F, El-Kirat-Chatel S. Probing the Adhesion of the Common Freshwater Diatom Nitzschia palea at Nanoscale. ACS APPLIED MATERIALS & INTERFACES 2019; 11:48574-48582. [PMID: 31766843 DOI: 10.1021/acsami.9b17821] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Freshwater biofilms play an essential ecological role, but they also adversely affect human activities through undesirable biofouling of artificial submerged structures. They form complex aggregates of microorganisms that colonize any type of substratum. In phototrophic biofilms, diatoms dominate in biomass and produce copious amount of extracellular polymeric substances (EPSs), making them efficient early colonizers. Therefore, a better understanding of diatoms adhesive properties is essential to develop new anti-biofouling strategies. In this context, we used atomic force microscopy (AFM) to decipher the topography and adhesive mechanisms of the common freshwater diatom Nitzschia palea. Images taken in physiological conditions revealed typical ultrastructural features with a few nanometers resolution. Using single-cell force spectroscopy, we showed that N. palea strongly adheres to hydrophobic surfaces as compared to hydrophilic ones. Chemical force spectroscopy with hydrophobic tips further confirmed that the adhesion is governed by surface-associated hydrophobic EPS distributed in clusters at the frustule surface, and mostly composed of (glyco)-lipids as revealed by Raman spectroscopy. Collectively, our results demonstrate that AFM-based nanoscopy, combined with Raman spectroscopy, is a powerful tool to provide new insights into the adhesion mechanisms of diatoms.
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Affiliation(s)
- Martin Laviale
- Université de Lorraine, CNRS, LIEC , F-57000 Metz , France
| | | | - Joey Allen
- Université de Lorraine, CNRS, LIEC , F-57000 Metz , France
| | - Fabienne Quilès
- Université de Lorraine, CNRS, LCPME , F-54000 Nancy , France
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10
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Effect of Surface Tungstate W5+ Species on the Metathesis Activity of W-Doped Spherical Silica Catalysts. Top Catal 2018. [DOI: 10.1007/s11244-018-1020-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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11
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Lin S, Jones JR. The effect of serum proteins on apatite growth for 45S5 Bioglass and common sol-gel derived glass in SBF. BIOMEDICAL GLASSES 2018. [DOI: 10.1515/bglass-2018-0002] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Abstract
The inhibitive effects of serum proteins on apatite growth was compared between melt-derived 45S5 Bioglass® and sol-gel derived bioactive glass of the 70S30C (70 mol% SiO2, 30 mol% CaO). By using techniques of XRD, TEM and Raman spectroscopy, the transformation of amorphous calcium phosphate to crystalline apatite, and the resulting size and aspect ratio of the crystals, in simulated body fluid (SBF), was seen to decrease in the presence of serum. XRD showed more rapid HA formation on Bioglass particles, compared to that forming on 70S30C particles, however TEM showed similar size and frequency of the needle-like crystals. Phosphate reduction in SBF was similar for Bioglass and 70S30C. Calcium carbonate formation was more likely on the phosphate-free sol-gel glass than on Bioglass.
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Liu D, Yu W, Deng L, Yuan W, Ma L, Yuan P, Du P, He H. Possible mechanism of structural incorporation of Al into diatomite during the deposition process I. Via a condensation reaction of hydroxyl groups. J Colloid Interface Sci 2016; 461:64-68. [DOI: 10.1016/j.jcis.2015.08.058] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2015] [Revised: 08/23/2015] [Accepted: 08/24/2015] [Indexed: 11/16/2022]
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Watling KM, Parr JF, Rintoul L, Brown CL, Sullivan LA. Raman, infrared and XPS study of bamboo phytoliths after chemical digestion. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2011; 80:106-11. [PMID: 21458368 DOI: 10.1016/j.saa.2011.03.002] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/29/2010] [Revised: 12/14/2010] [Accepted: 03/01/2011] [Indexed: 05/04/2023]
Abstract
Raman, infrared and X-ray photoelectron spectroscopies have been used to examine the effect of various chemical digestion methods on the composition of bamboo phytoliths. Intact bilobate phytoliths, suitable for interrogation by Raman microprobe analysis, were isolated by a microwave wet ashing technique using hydrogen peroxide with nitric and hydrochloric acids. The occluded phytolith carbon presented evidence of cellulose, lignin and carboxylic acids. Nitrate from the nitric acid used in the digestion was observed in homogenized samples of the isolated phytoliths; in addition to nitrogen of plant origin occluded within the phytolith, which was observed as amine nitrogen and ammonia. Intact bilobate phytoliths were not observed following an exothermic hydrogen peroxide/sulfuric acid digest, suggesting that these structures ruptured during this digestion procedure. The silicate network was significantly altered during isolation using the exothermic hydrogen peroxide/sulfuric digest, with surface hydroxyls undergoing condensation to form a SiO(3) ring structure.
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Affiliation(s)
- Kym M Watling
- Southern Cross University, Southern Cross GeoScience, Lismore, NSW, Australia.
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14
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Katsumata H, Kaneco S, Suzuki T, Ohta K. Determination of atrazine and simazine in water samples by high-performance liquid chromatography after preconcentration with heat-treated diatomaceous earth. Anal Chim Acta 2006; 577:214-9. [PMID: 17723674 DOI: 10.1016/j.aca.2006.06.052] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2006] [Revised: 06/21/2006] [Accepted: 06/21/2006] [Indexed: 11/16/2022]
Abstract
A sensitive and selective column adsorption method is proposed for the preconcentration and determination of atrazine and simazine. Atrazine and simazine were preconcentrated on heat-treated diatomaceous earth as an adsorbent and then determined by high-performance liquid chromatography (HPLC). Several parameters on the recoveries of the analytes were investigated. The experimental results showed that it was possible to obtain quantitative analysis when the solution pH was 2 using 100 mL of validation solution containing 1.5 microg of triazines and 5 mL of ethanol as an eluent. Recoveries of atrazine and simazine were 95.7+/-4.2% and 75.0+/-1.9% with a relative standard deviation for seven determinations of 4.7% and 2.7% under optimum conditions. The maximum preconcentration factor was 100 for triazines when 500 mL of sample solution volume was used. The linear ranges of calibration curves for atrazine and simazine were 1-150 ng mL(-1) and 1-300 ng mL(-1), respectively, with correlation coefficients of 0.999 and the detection limits (3Signal-to-Noise) were 0.24 ng mL(-1) and 0.21 ng mL(-1) for atrazine and simazine. The capacity of the adsorbent was also examined and found to be 0.8 mg g(-1) and 1.3 mg g(-1) for atrazine and simazine, respectively. The proposed method was successfully applied to the determination of triazines in river water and tap water samples with high precision and accuracy.
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Affiliation(s)
- Hideyuki Katsumata
- Department of Chemistry for Materials, Graduate School of Engineering, Mie University, Tsu, Mie 514-8507, Japan.
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