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Laird M, Herrmann N, Carcel C, Trens P, Oliviero E, Toquer G, Le Parc R, Bantignies JL, Bartlett JR, Wong Chi Man M. Mesoporous organosilicas with thiol functionalised pores: multifunctional dendrimers as sacrificial building block and template. Nanoscale 2022; 14:15617-15634. [PMID: 36070553 DOI: 10.1039/d2nr03097g] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
The synthesis of multifunctional poly(amidoamine) (PAMAM)-based dendrimers containing a cleavable disulfide linker within each arm of the dendrimer, together with condensable triethoxysilyl groups on the periphery of the dendrimer, is described. The dendrimers were mixed with 1,4-bis(triethoxysilyl)benzene and subsequently transformed into silsesquioxane gels or periodic mesoporous organosilicas (PMOs) to generate materials with dendrimers covalently embedded within the interior of the silsesquioxane networks. Subsequent treatment of the gels with dithiothreitol enabled the core of the dendrimers to be selectively cleaved at the disulfide site, thus generating thiol functions localised within the pores. The effect of different dendrimer generations on the reactivity of the pendant thiol functions was probed by impregnation with gold salts, which were reduced to obtain gold nanoparticles within the pore networks of the gels and PMOs. The gels yielded polydisperse gold nanoparticles (2 to 70 nm) with dimensions modulated by the generation of the dendrimer, together with well-defined gold/thiolate clusters with Au⋯S distances of 2.3 Å. Such clusters were also observed in the PMO system, together with monodispersed gold nanoparticles with diameters comparable to that of the organised pores in the PMO. The role of surface functionalisation in controlling the formation of gold clusters and/or nanoparticles is discussed.
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Affiliation(s)
- Mathilde Laird
- ICGM, Univ. Montpellier, CNRS, ENSCM, Montpellier, France.
| | | | - Carole Carcel
- ICGM, Univ. Montpellier, CNRS, ENSCM, Montpellier, France.
| | - Philippe Trens
- ICGM, Univ. Montpellier, CNRS, ENSCM, Montpellier, France.
| | | | | | - Rozenn Le Parc
- Laboratoire Charles Coulomb (L2C), CNRS-Univ. Montpellier, Montpellier, France
| | | | - John R Bartlett
- Western Sydney University, Locked Bag 1797, Penrith, NSW 2751, Australia.
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Birault A, Giret S, Théron C, Gallud A, Da Silva A, Durand D, Nguyen C, Bettache N, Gary-Bobo M, Bartlett JR, Wong Chi Man M, Carcel C. Sequential delivery of synergistic drugs by silica nanocarriers for enhanced tumour treatment. J Mater Chem B 2021; 8:1472-1480. [PMID: 31995094 DOI: 10.1039/c9tb02225b] [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] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Herein hybrid silica nanoparticles have been engineered to direct the sequential delivery of multiple chemotherapeutic drugs in response to external stimuli such as variations in pH. The nanocarriers consist of conventional MCM-41-type nanoparticles, which have been functionalised with an organic ligand (or stalk) grafted onto the external surface. The stalk is designed to "recognise" a complementary molecule, which serves as a "cap" to block the pores of the nanoparticles. First, camptothecin is introduced into the pores by diffusion prior to capping the pore apertures via molecular recognition. The cap, which is a derivative of 5-fluorouracil, serves as a second cytotoxic drug for synergistic chemotherapy. In vitro tests revealed that negligible release of the drugs occurred at pH 7.4, thus avoiding toxic side effects in the blood stream. In contrast, the stalk/cap complex is destabilised within the endolysosomal compartment (pH 5.5) of cancer cells, where release of the drugs was demonstrated. Furthermore, this environmentally responsive system exhibited a synergistic effect of the two drugs, where the pH-triggered release of the cytotoxic cap followed by diffusion-controlled release of the drug cargo within the pores led to essentially complete elimination of breast cancer cells.
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Affiliation(s)
- Albane Birault
- ICGM, Univ. Montpellier, CNRS, ENSCM, Montpellier, France.
| | - Simon Giret
- ICGM, Univ. Montpellier, CNRS, ENSCM, Montpellier, France.
| | | | - Audrey Gallud
- Institut des Biomolécules Max Mousseron, UMR5247, Université de Montpellier, CNRS, ENSCM, Faculté de Pharmacie, 15 Avenue Charles Flahault, 34093, Montpellier, Cedex 05, France
| | - Afitz Da Silva
- Institut des Biomolécules Max Mousseron, UMR5247, Université de Montpellier, CNRS, ENSCM, Faculté de Pharmacie, 15 Avenue Charles Flahault, 34093, Montpellier, Cedex 05, France
| | - Denis Durand
- Institut des Biomolécules Max Mousseron, UMR5247, Université de Montpellier, CNRS, ENSCM, Faculté de Pharmacie, 15 Avenue Charles Flahault, 34093, Montpellier, Cedex 05, France
| | - Christophe Nguyen
- Institut des Biomolécules Max Mousseron, UMR5247, Université de Montpellier, CNRS, ENSCM, Faculté de Pharmacie, 15 Avenue Charles Flahault, 34093, Montpellier, Cedex 05, France
| | - Nadir Bettache
- Institut des Biomolécules Max Mousseron, UMR5247, Université de Montpellier, CNRS, ENSCM, Faculté de Pharmacie, 15 Avenue Charles Flahault, 34093, Montpellier, Cedex 05, France
| | - Magali Gary-Bobo
- Institut des Biomolécules Max Mousseron, UMR5247, Université de Montpellier, CNRS, ENSCM, Faculté de Pharmacie, 15 Avenue Charles Flahault, 34093, Montpellier, Cedex 05, France
| | - John R Bartlett
- University of the Sunshine Coast, 90 Sippy Downs Drive, Sippy Downs QLD 4556, Australia and Western Sydney University, Locked Bag 1797, Penrith, NSW 2751, Australia
| | | | - Carole Carcel
- ICGM, Univ. Montpellier, CNRS, ENSCM, Montpellier, France.
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Laird M, Herrmann N, Ramsahye N, Totée C, Carcel C, Unno M, Bartlett JR, Wong Chi Man M. Large Polyhedral Oligomeric Silsesquioxane Cages: The Isolation of Functionalized POSS with an Unprecedented Si
18
O
27
Core. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202010458] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
| | | | | | - Cédric Totée
- ICGM Univ. Montpellier CNRS ENSCM Montpellier France
| | - Carole Carcel
- ICGM Univ. Montpellier CNRS ENSCM Montpellier France
| | - Masafumi Unno
- Department of Chemistry and Chemical Biology Graduate School of Science and Technology Gunma University Kiryu 376-8515 Gunma Japan
| | - John R. Bartlett
- Western Sydney University Locked Bag 1797 Penrith NSW 2751 Australia
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Laird M, Herrmann N, Ramsahye N, Totée C, Carcel C, Unno M, Bartlett JR, Wong Chi Man M. Large Polyhedral Oligomeric Silsesquioxane Cages: The Isolation of Functionalized POSS with an Unprecedented Si 18 O 27 Core. Angew Chem Int Ed Engl 2021; 60:3022-3027. [PMID: 33043577 DOI: 10.1002/anie.202010458] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [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: 07/30/2020] [Indexed: 12/19/2022]
Abstract
The synthesis of organo-functionalized polyhedral oligomeric silsesquioxanes (POSS, (R-SiO1.5 )n , Tn ) is an area of significant activity. To date, T14 is the largest such cage synthesized and isolated as a single isomer. Herein, we report an unprecedented, single-isomer styryl-functionalized T18 POSS. Unambiguously identified among nine possible isomers by multinuclear solution NMR (1 H, 13 C, and 29 Si), MALDI-MS, FTIR, and computational studies, this is the largest single-isomer functionalized Tn compound isolated to date. A ring-strain model was developed to correlate the 29 Si resonances with the number of 6-, 5-, and/or 4-Si-atom rings that each non-equivalent Si atom is part of. The model successfully predicts the speciation of non-equivalent Si atoms in other families of Tn compounds, demonstrating its general applicability for assigning 29 Si resonances to Si atoms in cage silsesquioxanes and providing a useful tool for predicting Si-atom environments.
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Affiliation(s)
- Mathilde Laird
- ICGM, Univ. Montpellier, CNRS, ENSCM, Montpellier, France
| | | | | | - Cédric Totée
- ICGM, Univ. Montpellier, CNRS, ENSCM, Montpellier, France
| | - Carole Carcel
- ICGM, Univ. Montpellier, CNRS, ENSCM, Montpellier, France
| | - Masafumi Unno
- Department of Chemistry and Chemical Biology, Graduate School of Science and Technology, Gunma University, Kiryu, 376-8515, Gunma, Japan
| | - John R Bartlett
- Western Sydney University, Locked Bag 1797, Penrith, NSW, 2751, Australia
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Laird M, Totée C, Gaveau P, Silly G, Van der Lee A, Carcel C, Unno M, Bartlett JR, Wong Chi Man M. Functionalised polyhedral oligomeric silsesquioxane with encapsulated fluoride - first observation of fluxional SiF interactions in POSS. Dalton Trans 2021; 50:81-89. [PMID: 33216075 DOI: 10.1039/d0dt03057k] [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] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The synthesis of a styryl functionalised POSS incorporating an encapsulated fluoride ion within a (SiO1.5)8 cage (T8-F) is reported. It was characterised by single crystal XRD, MALDI-MS, FTIR, solution (29Si, 19F, 13C, 1H) and solid state (29Si, 19F) NMR. In the absence of 1H decoupling, the 29Si solution NMR spectrum exhibited a triplet of doublets. In contrast, 1H, 19F and 1H/19F double-decoupling resulted in two, three and one signal, respectively, being consistent with a single Si site whose 29Si NMR signal is modulated by both the proximal aromatic-ring protons and fluoride. The associated SiF coupling constant (2.5 Hz) is substantially lower than expected for a covalent Si-F bond and arises from a fluxional SiF covalent effect in which the F- interacts equivalently with all eight Si atoms. Additional variable temperature NMR studies demonstrated a threshold at -5 °C below which no SiF interactions are observed, and above which an increasing SiF covalent character occurs.
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Affiliation(s)
- Mathilde Laird
- ICGM Univ. Montpellier, CNRS, ENSCM, Montpellier, France.
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Laird M, Gaveau P, Trens P, Carcel C, Unno M, Bartlett JR, Wong Chi Man M. Post-synthesis modification of functionalised polyhedral oligomeric silsesquioxanes with encapsulated fluoride – enhancing reactivity of T 8-F POSS for materials synthesis. NEW J CHEM 2021. [DOI: 10.1039/d0nj06008a] [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] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
The first successful approach for modifying poorly reactive POSS containing F− (T8-F) and incorporating intact T8-F within a nanohybrid material is described.
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Affiliation(s)
| | | | | | | | - Masafumi Unno
- Department of Chemistry and Chemical Biology
- Graduate School of Science and Technology
- Gunma University
- Kiryu 376-8515
- Japan
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Laird M, Van der Lee A, Dumitrescu DG, Carcel C, Ouali A, Bartlett JR, Unno M, Wong Chi Man M. Styryl-Functionalized Cage Silsesquioxanes as Nanoblocks for 3-D Assembly. Organometallics 2020. [DOI: 10.1021/acs.organomet.0c00119] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Mathilde Laird
- ICGM, Université de Montpellier, CNRS, ENSCM, 34095 Montpellier, France
| | - Arie Van der Lee
- Institut Européen des Membranes, Université de Montpellier, UMR 5632 CNRS ENSCM, 34095 Montpellier, France
| | - Dan G. Dumitrescu
- XRD2 Beamline, Elettra − Sincrotrone Trieste S.C.p.A., Strada Statale 14-km 163,5 in AREA Science Park, 34149 Basovizza, Trieste, Italy
| | - Carole Carcel
- ICGM, Université de Montpellier, CNRS, ENSCM, 34095 Montpellier, France
| | - Armelle Ouali
- ICGM, Université de Montpellier, CNRS, ENSCM, 34095 Montpellier, France
| | - John R. Bartlett
- Western Sydney University, Locked Bag 1797, Penrith, NSW 2751, Australia
| | - Masafumi Unno
- Department of Chemistry and Chemical Biology, Graduate School of Science and Technology, Gunma University, Kiryu 376-8515, Gunma, Japan
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Birault A, Molina E, Trens P, Cot D, Toquer G, Marcotte N, Carcel C, Bartlett JR, Gérardin C, Wong Chi Man M. Periodic Mesoporous Organosilicas from Polyion Complex Micelles – Effect of Organic Bridge on Nanostructure. Eur J Inorg Chem 2019. [DOI: 10.1002/ejic.201900487] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Albane Birault
- Institut Charles Gerhardt Montpellier UMR 5253 CNRS, ENSCM Univ. Montpellier Montpellier France
| | - Emilie Molina
- Institut Charles Gerhardt Montpellier UMR 5253 CNRS, ENSCM Univ. Montpellier Montpellier France
| | - Philippe Trens
- Institut Charles Gerhardt Montpellier UMR 5253 CNRS, ENSCM Univ. Montpellier Montpellier France
| | - Didier Cot
- Institut Européen des Membrane ‐ UMR 5635 ENSCM, CNRS Univ. Montpellier Montpellier France
| | - Guillaume Toquer
- Institut de Chimie Séparative de Marcoule ‐ UMR 5257, CEA CNRS, ENSCM Univ. Montpellier Marcoule France
| | - Nathalie Marcotte
- Institut Charles Gerhardt Montpellier UMR 5253 CNRS, ENSCM Univ. Montpellier Montpellier France
| | - Carole Carcel
- Institut Charles Gerhardt Montpellier UMR 5253 CNRS, ENSCM Univ. Montpellier Montpellier France
| | - John R. Bartlett
- CNRS, ENSCM University of the Sunshine Coast 90 Sippy Downs Drive 4556 Sippy Downs QLD Australia
- CNRS, ENSCM Western Sydney University Locked Bag 1797 2751 Penrith NSW Australia
| | - Corine Gérardin
- Institut Charles Gerhardt Montpellier UMR 5253 CNRS, ENSCM Univ. Montpellier Montpellier France
| | - Michel Wong Chi Man
- Institut Charles Gerhardt Montpellier UMR 5253 CNRS, ENSCM Univ. Montpellier Montpellier France
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Le Parc R, Freitas VT, Hermet P, Cojocariu AM, Cattoën X, Wadepohl H, Maurin D, Tse CH, Bartlett JR, Ferreira RAS, Carlos LD, Wong Chi Man M, Bantignies JL. Infrared and Raman spectroscopy of non-conventional hydrogen bonding between N,N'-disubstituted urea and thiourea groups: a combined experimental and theoretical investigation. Phys Chem Chem Phys 2019; 21:3310-3317. [PMID: 30688324 DOI: 10.1039/c8cp06625f] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
The variety of H bond (HB) interactions is a source of inspiration for bottom-up molecular engineering through self-aggregation. Non-conventional intermolecular HBs between N,N'-disubstituted urea and thiourea are studied in detail by vibrational spectroscopies and ab initio calculations. Raman and IR mode assignments are given. We show that it is possible to study selectively the different intermolecular bifurcated intra- and inter-dimer HBs with the two types of HB acceptors. Through the ab initio calculation, the thioamide I mode, a specific marker of N-HS[double bond, length as m-dash]C HB interactions, is unambiguously identified.
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Affiliation(s)
- Rozenn Le Parc
- Laboratoire Charles Coulomb, UMR CNRS 5221, Université de Montpellier, 34095 Montpellier, France.
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11
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Birault A, Molina E, Toquer G, Lacroix-Desmazes P, Marcotte N, Carcel C, Katouli M, Bartlett JR, Gérardin C, Wong Chi Man M. Large-Pore Periodic Mesoporous Organosilicas as Advanced Bactericide Platforms. ACS Appl Bio Mater 2018; 1:1787-1792. [PMID: 34996279 DOI: 10.1021/acsabm.8b00474] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Despite the versatility of periodic mesoporous organosilicas (PMOs), the bactericide capacity of these hybrid platforms has seldom been explored. Herein, we describe the synthesis of large-pore phenylene-bridged PMOs, mesostructured by polyion complex (PIC) micelles (PICPMOs) incorporating an antibiotic, neomycin B. A key feature of this approach is that the bioactive molecules are directly encapsulated within the PICPMOs during their formation. The engineered PICPMOs exhibit a well-ordered hexagonal mesophase with a molecular-scale crystallinity and large mesopores (8 nm), which facilitates pH-triggered delivery of the drug. The results obtained with a pathogenic Escherichia coli strain clearly demonstrate the potential of such PICPMOs for antibacterial applications.
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Affiliation(s)
- Albane Birault
- ICGM, Univ Montpellier, CNRS, ENSCM, Montpellier 34090, France
| | - Emilie Molina
- ICGM, Univ Montpellier, CNRS, ENSCM, Montpellier 34090, France
| | - Guillaume Toquer
- Institut de Chimie Séparative de Marcoule UMR 5257, CEA, CNRS, ENSCM, Univ Montpellier, Marcoule F-30207, France
| | | | | | - Carole Carcel
- ICGM, Univ Montpellier, CNRS, ENSCM, Montpellier 34090, France
| | - Mohammad Katouli
- Faculty of Science, Health, Education and Engineering, University of the Sunshine Coast, 90 Sippy Downs Dr, Sippy Downs, Queensland 4556, Australia
| | - John R Bartlett
- Faculty of Science, Health, Education and Engineering, University of the Sunshine Coast, 90 Sippy Downs Dr, Sippy Downs, Queensland 4556, Australia
| | - Corine Gérardin
- ICGM, Univ Montpellier, CNRS, ENSCM, Montpellier 34090, France
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12
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Brennan-Speranza TC, Mor D, Mason RS, Bartlett JR, Duque G, Levinger I, Levinger P. Skeletal muscle vitamin D in patients with end stage osteoarthritis of the knee. J Steroid Biochem Mol Biol 2017; 173:180-184. [PMID: 28161531 DOI: 10.1016/j.jsbmb.2017.01.022] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/15/2016] [Revised: 01/16/2017] [Accepted: 01/30/2017] [Indexed: 12/12/2022]
Abstract
Muscle function is often impaired in patients with knee osteoarthritis (OA), with reduced strength and increased pain. The role of vitamin D and the vitamin D-endocrine pathway in muscle health has recently been placed in the spotlight, with various groups reporting positive effects on muscle development, function and health. Recently, it has been shown that uptake into muscle of the specialized vitamin D binding protein (DBP) is dependent on the endocytic receptor, megalin. Here we analyse circulating vitamin D, and muscle DBP, megalin and the cognate vitamin D receptor (VDR) in patients with knee OA and compare them to asymptomatic controls. Muscle and blood samples were collected from 19 patients with end-stage OA of the knee and 10 age-matched controls. Muscle biopsies from the OA group were performed during knee replacement surgery and a needle biopsy was used on control volunteers. Immunoblots performed with specific antibodies were used to detect the presence of DBP, megalin, VDR (using the specific D-6 antibody) and albumin in the muscle biopsies. Results were correlated with FoxO1, a key regulator of the ubiquitin-proteasome degradation pathway in muscle. There were no differences in circulating levels of 25 (OH) vitamin D3 between the groups, and no subjects were vitamin D deficient. We found increased VDR, DBP and albumin protein in the muscle from patients with OA compared to controls, with no change in muscle megalin expression. Furthermore, DBP levels in the muscle correlated with FoxO1, suggesting an association between muscle protein breakdown and the activation of the vitamin D-endocrine pathway in muscle surrounding an OA affected joint. We show, for the first time, that the factors involved in the vitamin D-endocrine-pathway are present at higher levels in muscles from OA patients compared to asymptomatic controls. This is despite no differences in circulating 25 (OH) vitamin D levels between the groups. These findings indicate the activation of vitamin D pathway in these muscles that may provide a beneficial compensatory stimulation of the repair process in muscles that are subject to inflammatory and proteolytic processes.
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Affiliation(s)
- Tara C Brennan-Speranza
- Department of Physiology and Bosch Institute for Medical Research, University of Sydney, Sydney, Australia.
| | - David Mor
- Discipline of Biomedical Sciences and Bosch Institute for Medical Research, University of Sydney, Sydney, Australia
| | - Rebecca S Mason
- Department of Physiology and Bosch Institute for Medical Research, University of Sydney, Sydney, Australia
| | - John R Bartlett
- Warringal Private Medical Centre, Heidelberg, Victoria, Australia
| | - Gustavo Duque
- Australian Institute for Musculoskeletal Science (AIMSS), The University of Melbourne and Western Health, St. Albans, VIC, Australia; Department of Medicine, Melbourne Medical School-Western Precinct, The University of Melbourne, St. Albans, VIC, Australia
| | - Itamar Levinger
- Institute of Sport, Exercise and Active Living (ISEAL), Victoria University, Melbourne, Australia
| | - Pazit Levinger
- Institute of Sport, Exercise and Active Living (ISEAL), Victoria University, Melbourne, Australia
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Levinger P, Wee E, Margelis S, Menz HB, Bartlett JR, Bergman NR, McMahon S, Hill KD. Pre-operative predictors of post-operative falls in people undergoing total hip and knee replacement surgery: a prospective study. Arch Orthop Trauma Surg 2017; 137:1025-1033. [PMID: 28597247 DOI: 10.1007/s00402-017-2727-6] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [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: 10/20/2016] [Indexed: 02/09/2023]
Abstract
INTRODUCTION Pain and disability often persist following hip (THR) and knee replacement (TKR) surgery predisposing patients to increased risk of falling. This study identified pre-operative predictors for post-operative falls in TKR and THR patients, and the incidence and circumstances of falls in the 12 months post-surgery. MATERIALS AND METHODS A survey was undertaken of patients before THR and TKR, and was repeated 12 months post-operation. The survey included (1) medical history and medications usage, (2) pain and function, (3) health-related and physical activity and (4) fear of falls and history of falls questionnaires. Patients were classified as 'fallers' (≥1 fall) or 'non-fallers' based on prospectively documented falls in the 12 months post-surgery. Binary logistic regression was conducted to identify independent pre-operative predictors of incident falls status. RESULTS Eighty-two of the 243 participants (33.7%) reported ≥1 fall in the 12 months post-operatively [60 (34.1%) patients following TKR and 22 (32.8%) following THR]. The logistic regression model was statistically significant, χ 2 = 24.731, p < 0.001, the model explaining 22% of the variance in falls, and correctly classifying 73.7% of cases as fallers or non-fallers. Reduced SF-36v2 general health sub-scale, increased planned physical activity and previous falls in the preceding year were predictors of falls. Those reporting ≥1 fall pre-operatively were three times more likely to fall post-operatively. CONCLUSION People awaiting hip or knee joint replacement surgery might present with complex conditions that predispose them to greater risk of falling post-operation. Review of general health and history of falling is recommended pre-operatively to identify patients at risk.
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Affiliation(s)
- Pazit Levinger
- Institute of Sport, Exercise and Active Living (ISEAL), College of Sport and Exercise Science, Victoria University, PO Box 14428, Melbourne, VIC, 8001, Australia. .,Faculty of Health Sciences, School of Allied Health, College of Science, Health and Engineering, La Trobe University, Bundoora, VIC, 3086, Australia.
| | - Elin Wee
- Faculty of Health Sciences, School of Allied Health, College of Science, Health and Engineering, La Trobe University, Bundoora, VIC, 3086, Australia
| | - Soula Margelis
- Faculty of Health Sciences, School of Allied Health, College of Science, Health and Engineering, La Trobe University, Bundoora, VIC, 3086, Australia
| | - Hylton B Menz
- Faculty of Health Sciences, School of Allied Health, College of Science, Health and Engineering, La Trobe University, Bundoora, VIC, 3086, Australia
| | - John R Bartlett
- Warringal Private Medical Centre, Heidelberg, VIC, 3084, Australia
| | - Neil R Bergman
- Warringal Private Medical Centre, Heidelberg, VIC, 3084, Australia
| | | | - Keith D Hill
- School of Physiotherapy and Exercise Science, Curtin University, Perth, WA, 6845, Australia
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14
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Levinger P, Diamond NT, Menz HB, Wee E, Margelis S, Stewart AG, Bartlett JR, Bergman NB, McMahon S, Hare DL, Hill K. Development and validation of a questionnaire assessing discrepancy between patients' pre-surgery expectations and abilities and post-surgical outcomes following knee replacement surgery. Knee Surg Sports Traumatol Arthrosc 2016; 24:3359-3368. [PMID: 25423872 DOI: 10.1007/s00167-014-3432-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [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: 08/08/2014] [Accepted: 11/10/2014] [Indexed: 11/30/2022]
Abstract
PURPOSE The discrepancy between patient-desired outcomes and achievable functional outcomes is a source of patient dissatisfaction. This paper reports development and validation of a questionnaire to assess this discrepancy in patients undergoing knee replacement surgery. METHODS The initial questionnaire (Knee Surgery Perception Questionnaire, KSPQ) comprised two parts. Part A, assessed patients' perception of their current level of function and pain, and Part B, assessed patients' desired outcomes of the surgery. Validation was carried out for Part A and then applied to Part B using a one-factor congeneric model and was tested in 185 patients preceding surgery. A discrepancy score between patients' expectations and desired outcome (Part B) and their perception of current function (Part A) was also calculated. Pearson correlations were used between the KSPQ total score and subscales and other knee-specific questionnaires to determine construct validity. RESULTS The final best set of models included four items for each subscale with a Chi-square value of 7.3 (n.s). The subscales and the total KSPQ showed significant strong to moderate correlations with knee-specific questionnaires. The discrepancy score in each subscale and the overall score showed relatively large discrepancy between patients' expectations and their perception of current function; with higher discrepancy score reported for pain and walking. CONCLUSION The KSPQ is a valid questionnaire to assess patients' expected and desired outcomes of knee replacement surgery and their perception of their current abilities and function, and discrepancy between these. The KSPQ now requires further investigation at different stages of recovery following surgery. LEVEL OF EVIDENCE III.
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Affiliation(s)
- Pazit Levinger
- Institute of Sport, Exercise and Active Living (ISEAL), College of Sport and Exercise Science, Victoria University, PO Box 14428, Melbourne, VIC, 8001, Australia. .,Lower Extremity and Gait Studies Program, School of Allied Health, La Trobe University, Bundoora, VIC, Australia.
| | - Neil T Diamond
- ESQUANT Statistical Consulting, Melbourne, VIC, Australia
| | - Hylton B Menz
- Lower Extremity and Gait Studies Program, School of Allied Health, La Trobe University, Bundoora, VIC, Australia
| | - Elin Wee
- Lower Extremity and Gait Studies Program, School of Allied Health, La Trobe University, Bundoora, VIC, Australia
| | - Soula Margelis
- Lower Extremity and Gait Studies Program, School of Allied Health, La Trobe University, Bundoora, VIC, Australia
| | - Andrew G Stewart
- Austin Hospital and University of Melbourne, Melbourne, VIC, Australia
| | - John R Bartlett
- Warringal Private Medical Centre, Heidelberg, VIC, Australia
| | - Neil B Bergman
- Warringal Private Medical Centre, Heidelberg, VIC, Australia
| | | | - David L Hare
- ESQUANT Statistical Consulting, Melbourne, VIC, Australia
| | - Keith Hill
- School of Physiotherapy and Exercise Science, Curtin University, Perth, WA, Australia.,Public Health Division, National Ageing Research Institute, Parkville, VIC, Australia
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Levinger P, Caldow MK, Bartlett JR, Peake JM, Smith C, Cameron-Smith D, Levinger I. The level of FoxO1 and IL-15 in skeletal muscle, serum and synovial fluid in people with knee osteoarthritis: a case control study. Osteoporos Int 2016; 27:2137-43. [PMID: 26762130 DOI: 10.1007/s00198-015-3473-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/01/2015] [Accepted: 12/21/2015] [Indexed: 12/24/2022]
Abstract
UNLABELLED The molecular regulation of muscle function in knee osteoarthritis is unclear. Elevated muscle atrophy regulation marker expression was associated with reduced muscle strength in knee osteoarthritis. The level of protein expression appears to be different between muscle, knee joint and serum, suggesting that inflammation is regulated differently within these tissues. INTRODUCTION Impaired muscle function is common in knee osteoarthritis (OA). Numerous biochemical molecules have been implicated in the development of OA; however, these have only been identified in the joint and serum. We compared the expression of interleukin-15 (IL-15) and Forkhead box protein-O1 (FoxO1) in muscle of patients with knee OA and asymptomatic individuals and examined whether IL-15 was also present in the joint and serum. METHODS Muscle and blood samples were collected from 19 patients with knee OA and 10 age-matched asymptomatic individuals. Synovial fluid and muscle biopsies were collected from the OA group during knee replacement surgery. IL-15 and FoxO1 were measured in the skeletal muscle. IL-15 abundance was also analysed in the serum of both groups and synovial fluid from the OA group. Knee extensor strength was measured and correlated with IL-15 and FoxO1 in the muscle. RESULTS FoxO1 protein expression was higher (p = 0.04), whereas IL-15 expression was lower (p = 0.02) in the muscle of the OA group. Strength was also lower in the OA group and was inversely correlated with FoxO1 expression. No correlation was found between IL-15 in the joint, muscle or serum. CONCLUSION Skeletal muscle, particularly the quadriceps, is affected in people with knee OA where elevated FoxO1 protein expression was associated with reduced muscle strength. While IL-15 protein expression in the muscle was lower in the knee OA group, no correlation was found between the expression of IL-15 protein in the muscle, joint and serum, which suggests that inflammation is regulated differently within these tissues. Australian Clinical Trials Registry (ACTR) number: ACTRN12613000467730 ( http://www.anzctr.org.au/TrialSearch.aspx?searchTxt=ACTRN12613000467730&isBasic=True ).
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Affiliation(s)
- P Levinger
- Clinical Exercise Science Program, Institute of Sport, Exercise & Active Living (ISEAL), Victoria University, Melbourne, Victoria, Australia.
- Lower Extremity and Gait Studies Program, School of Allied Health, La Trobe University, Bundoora, Melbourne, Victoria, Australia.
| | - M K Caldow
- Basic and Clinical Myology Laboratory, Department of Physiology, University of Melbourne, Parkville, Melbourne, Australia
| | - J R Bartlett
- Warringal Private Medical Centre, Heidelberg, Melbourne, Victoria, Australia
| | - J M Peake
- School of Biomedical Sciences and Institute of Health and Biomedical Innovation, Queensland University of Technology, Brisbane, Australia
| | - C Smith
- Clinical Exercise Science Program, Institute of Sport, Exercise & Active Living (ISEAL), Victoria University, Melbourne, Victoria, Australia
| | - D Cameron-Smith
- Liggins Institute, The University of Auckland, Auckland, New Zealand
| | - I Levinger
- Clinical Exercise Science Program, Institute of Sport, Exercise & Active Living (ISEAL), Victoria University, Melbourne, Victoria, Australia
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Cojocariu AM, Cattoën X, Le Parc R, Maurin D, Blanc C, Dieudonné P, Bantignies JL, Wong Chi Man M, Bartlett JR. Evaporation-induced self-structuring of organised silica nanohybrid films through cooperative physical and chemical interactions. Phys Chem Chem Phys 2016; 18:7946-55. [PMID: 26958662 DOI: 10.1039/c5cp02742j] [Citation(s) in RCA: 6] [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
In this work, we develop the concept of evaporation-induced self-structuring as a novel approach for producing organised films by exploiting cooperative physical and chemical interactions under far-from-equilibrium conditions (spin-coating), using sol-gel precursors with multiple functional groups. Thin films of self-structured silsesquioxane nanohybrids have been deposited by spin coating through the sol-gel hydrolysis and condensation of a bridged organosilane bearing self-assembling urea groups. The resulting nanostructure, investigated by FTIR, AFM and SEM, is shown to be highly dependent on the catalyst used (nucleophilic or acidic), and can be further modulated by varying the spinning rate. FTIR studies revealed the presence of highly organised structures under acidic catalysis due to strong hydrogen bonding between urea groups and hydrophobic interactions between long alkylene chains. The preferential orientation of the urea cross-links parallel to the substrate is shown using polarized FTIR experiments.
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Affiliation(s)
- Ana M Cojocariu
- Faculty of Science, Health, Education and Engineering, University of the Sunshine Coast, Maroochydore DC, QLD 4558, Australia. and Institut Charles Gerhardt Montpellier, UMR 5253 ENSCM-Université Montpellier-CNRS, 8, rue de l'école normale, 34296 Montpellier, France and School of Science and Health, University of Western Sydney, Locked Bag 1797, Penrith, NSW 2751, Australia
| | - Xavier Cattoën
- Institut Charles Gerhardt Montpellier, UMR 5253 ENSCM-Université Montpellier-CNRS, 8, rue de l'école normale, 34296 Montpellier, France and CNRS Inst. Néel, F-38042 Grenoble, France. and Univ. Grenoble Alpes, Inst. Néel, F-38042 Grenoble, France
| | - Rozenn Le Parc
- Laboratoire Charles Coulomb (L2C), UMR 5221 CNRS-Université de Montpellier, Montpellier, France.
| | - David Maurin
- Laboratoire Charles Coulomb (L2C), UMR 5221 CNRS-Université de Montpellier, Montpellier, France.
| | - Christophe Blanc
- Laboratoire Charles Coulomb (L2C), UMR 5221 CNRS-Université de Montpellier, Montpellier, France.
| | - Philippe Dieudonné
- Laboratoire Charles Coulomb (L2C), UMR 5221 CNRS-Université de Montpellier, Montpellier, France.
| | - Jean-Louis Bantignies
- Laboratoire Charles Coulomb (L2C), UMR 5221 CNRS-Université de Montpellier, Montpellier, France.
| | - Michel Wong Chi Man
- Institut Charles Gerhardt Montpellier, UMR 5253 ENSCM-Université Montpellier-CNRS, 8, rue de l'école normale, 34296 Montpellier, France
| | - John R Bartlett
- Faculty of Science, Health, Education and Engineering, University of the Sunshine Coast, Maroochydore DC, QLD 4558, Australia. and School of Science and Health, University of Western Sydney, Locked Bag 1797, Penrith, NSW 2751, Australia
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Freitas VT, Fu L, Cojocariu AM, Cattoën X, Bartlett JR, Le Parc R, Bantignies JL, Man MWC, André PS, Ferreira RAS, Carlos LD. Eu³⁺-based bridged silsesquioxanes for transparent luminescent solar concentrators. ACS Appl Mater Interfaces 2015; 7:8770-8778. [PMID: 25835303 DOI: 10.1021/acsami.5b01281] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The sol-gel preparation of a bridged silsesquioxane containing europium(III) salts and 2-thenoyltrifluoroacetone has been achieved from a new ethane tetracarboxamide-based organosilane. Free-standing films with thicknesses up to 440 μm and maximum absolute quantum yield (q) of 0.34 ± 0.03 (excitation at 320 nm) were prepared by the drop cast method, while thin films (∼200-400 nm) spin-coated on glass substrates led to highly luminescent coatings with q = 0.60 ± 0.02 (excitation at 345 nm). The thin films were tested as planar luminescent solar concentrators and the optimized device displays an optical conversion efficiency of 12.3% in the absorbing spectral region of the active layer (300-380 nm).
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Affiliation(s)
- Vânia T Freitas
- †Physics Department and CICECO Aveiro Institute of Materials, University of Aveiro, 3810-193 Aveiro, Portugal
- ‡Laboratoire Charles Coulomb (L2C), UMR 5521 CNRS-Université de Montpellier, 34095 Montpellier, France
| | - Lianshe Fu
- †Physics Department and CICECO Aveiro Institute of Materials, University of Aveiro, 3810-193 Aveiro, Portugal
| | - Ana M Cojocariu
- §Institut Charles Gerhardt Montpellier, UMR 5253 CNRS-UM2-ENSCM-UM1, 34296 Montpellier, France
- ⊥Faculty of Science, Health, Education and Engineering, University of the Sunshine Coast, Maroochydore DC, QLD 4558 Australia
| | - Xavier Cattoën
- §Institut Charles Gerhardt Montpellier, UMR 5253 CNRS-UM2-ENSCM-UM1, 34296 Montpellier, France
- #Institut NEEL, CNRS, Université Grenoble-Alpes, 38042 Grenoble, France
| | - John R Bartlett
- ⊥Faculty of Science, Health, Education and Engineering, University of the Sunshine Coast, Maroochydore DC, QLD 4558 Australia
| | - Rozenn Le Parc
- ‡Laboratoire Charles Coulomb (L2C), UMR 5521 CNRS-Université de Montpellier, 34095 Montpellier, France
| | - Jean-Louis Bantignies
- ‡Laboratoire Charles Coulomb (L2C), UMR 5521 CNRS-Université de Montpellier, 34095 Montpellier, France
| | - Michel Wong Chi Man
- §Institut Charles Gerhardt Montpellier, UMR 5253 CNRS-UM2-ENSCM-UM1, 34296 Montpellier, France
| | - Paulo S André
- || Department of Electric and Computer Engineering and Instituto de Telecomunicações, Instituto Superior Técnico, Universidade de Lisboa, Lisboa, Portugal
| | - Rute A S Ferreira
- †Physics Department and CICECO Aveiro Institute of Materials, University of Aveiro, 3810-193 Aveiro, Portugal
| | - Luís D Carlos
- †Physics Department and CICECO Aveiro Institute of Materials, University of Aveiro, 3810-193 Aveiro, Portugal
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Beckford RC, Bartlett JR. Inclusion levels of sweet potato root meal in the diet of broilers I. Effect on performance, organ weights, and carcass quality. Poult Sci 2015; 94:1316-22. [PMID: 25840965 PMCID: PMC4988554 DOI: 10.3382/ps/pev090] [Citation(s) in RCA: 6] [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] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/03/2015] [Indexed: 11/20/2022] Open
Abstract
The amount of corn available for animal and poultry feed has been unpredictable in recent years due to the increased use of corn for ethanol production. As a consequence, there has been an increase in the price of feed, chicken, and chicken products. Researchers are exploring alternative feed sources to substitute for corn in poultry ration. This study evaluated the performance and carcass quality of broilers fed diets containing sweet potato root meal (SPRM). After a complete nutrient analysis of the SPRM, diets were formulated where 0, 10, 20, and 30% of corn was substituted with SPRM. The study utilized 360 1-d-old Cornish X Rock male broiler chickens randomly assigned to one of 4 treatments; 0%, 10%, 20%, and 30% SPRM. Body weights and feed intake (FI) were monitored weekly for 7 wk. Birds were slaughtered on d 50 and FI, BW gain, ADG, ADFI, abdominal fat, dressing percentage, and organ weights measured. White (breast) and dark (leg and thigh) meat were evaluated for nutrient content (protein, moisture, fat, and ash). Results showed birds fed 20% SPRM had lower (P < 0.03) final BW, BW gain and ADG than those fed the 30% SPRM diet. There were no differences in FI and ADFI among treatments. Feed conversion ratio was lowest (P < 0.02) in birds fed 10, 20, and 30% SPRM than the control. There were no differences in dressing percentage among treatments. Abdominal fat was highest (P < 0.05) in birds fed 30% SPRM. Organ weights were similar across treatments except for gizzard which weighed highest (P < 0.05) in the control. For white meat; moisture, protein, fat, and ash were similar across treatments. For dark meat, moisture (P < 0.004) and fat (P < 0.03) were highest in the control, while protein and ash were similar among treatments. Birds fed the SPRM diets compared well with those fed the control for both performance and nutrient content of meat.
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Affiliation(s)
- R C Beckford
- George Washington Carver Agricultural Experiment Station, Tuskegee University, Tuskegee AL 36088
| | - J R Bartlett
- George Washington Carver Agricultural Experiment Station, Tuskegee University, Tuskegee AL 36088
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Perry BD, Levinger P, Serpiello FR, Caldow MK, Cameron-Smith D, Bartlett JR, Feller JA, Bergman NR, Levinger I, McKenna MJ. The effects of osteoarthritis and age on skeletal muscle strength, Na+-K+-ATPase content, gene and isoform expression. J Appl Physiol (1985) 2013; 115:1443-9. [PMID: 24009010 DOI: 10.1152/japplphysiol.00789.2013] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Knee osteoarthritis (OA) is a debilitating disorder prevalent in older populations that is accompanied by declines in muscle mass, strength, and physical activity. In skeletal muscle, the Na(+)-K(+) pump (NKA) is pivotal in ion homeostasis and excitability and is modulated by disuse and exercise training. This study examined the effects of OA and aging on muscle NKA in 36 older adults (range 55-81 yr), including 19 with OA (69.9 ± 6.5 yr, mean ± SD) and 17 asymptomatic controls (CON, 66.8 ± 6.4 yr). Participants completed knee extensor strength testing and a physical activity questionnaire. A vastus lateralis muscle biopsy was analyzed for NKA content ([(3)H]ouabain binding sites), α1-3- and β1-3-isoform protein abundance (immunoblotting), and mRNA (real-time RT-PCR). The association between age and NKA content was investigated within the OA and CON groups and in pooled data. The NKA content was also contrasted between subgroups below and above the median age of 68.5 yr. OA had lower strength (-40.8%, P = 0.005), but higher NKA α2- (∼34%, P = 0.006) and α3-protein (100%, P = 0.016) abundance than CON and performed more incidental physical activity (P = 0.035). No differences were found between groups for NKA content, abundance of other NKA isoforms, or gene expression. There was a negative correlation between age and NKA content within OA (r = -0.63, P = 0.03) and with both groups combined (r = -0.47, P = 0.038). The NKA content was 25.5% lower in the older (69-81 yr) than in the younger (55-68 yr) subgroup. Hence older age, but not knee OA, was related to lowered muscle NKA content in older adults.
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Affiliation(s)
- Ben D Perry
- Institute of Sport, Exercise and Active Living (ISEAL Melbourne, Victoria, Australia
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Levinger P, Menz HB, Morrow AD, Bartlett JR, Feller JA, Bergman NR. Relationship between foot function and medial knee joint loading in people with medial compartment knee osteoarthritis. J Foot Ankle Res 2013; 6:33. [PMID: 23927830 PMCID: PMC3750767 DOI: 10.1186/1757-1146-6-33] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/18/2013] [Accepted: 06/25/2013] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Dynamic joint loading, particularly the external knee adduction moment (KAM), is an important surrogate measure for the medio-lateral distribution of force across the knee joint in people with knee osteoarthritis (OA). Foot motion may alter the load on the medial tibiofemoral joint and hence affect the KAM. Therefore, this study aimed to investigate the relationship between tibia, rearfoot and forefoot motion in the frontal and transverse planes and the KAM in people with medial compartment knee OA. METHOD Motion of the knee, tibia, rearfoot and forefoot and knee moments were evaluated in 32 patients with clinically and radiographically-confirmed OA, predominantly in the medial compartment. Pearson's correlation coefficient was used to investigate the association between peak values of tibia, rearfoot and forefoot motion in the frontal and transverse planes and 1st peak KAM, 2nd peak KAM, and the knee adduction angular impulse (KAAI). RESULTS Lateral tilt of the tibia was significantly associated with increased 1st peak KAM (r = 0.60, p < 0.001), 2nd peak KAM (r = 0.67, p = 0.001) and KAAI (r = 0.82, p = 0.001). Increased peak rearfoot eversion was significantly correlated with decreased 2nd peak KAM (r = 0.59, p < 0.001) and KAAI (r = 0.50, p = 0.004). Decreased rearfoot internal rotation was significantly associated with increased 2nd peak KAM (r = -0.44, p = 0.01) and KAAI (r = -0.38, p = 0.02), while decreased rearfoot internal rotation relative to the tibia was significantly associated with increased 2nd peak KAM (r = 0.43, p = 0.01). Significant negative correlations were found between peak forefoot eversion relative to the rearfoot and 2nd peak KAM (r = -0.53, p = 0.002) and KAAI (r = -0.51, p = 0.003) and between peak forefoot inversion and 2nd peak KAM (r = -0.54, p = 0.001) and KAAI (r = -0.48, p = 0.005). CONCLUSION Increased rearfoot eversion, rearfoot internal rotation and forefoot inversion are associated with reduced knee adduction moments during the stance phase of gait, suggesting that medial knee joint loading is reduced in people with OA who walk with greater foot pronation. These findings have implications for the design of load-modifying interventions in people with knee OA.
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Affiliation(s)
- Pazit Levinger
- Institute of Sport, Exercise and Active Living, College of Sport and Exercise Science, Victoria University, Melbourne Vic 8001, Australia.
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Levinger P, Menz HB, Morrow AD, Feller JA, Bartlett JR, Bergman NR. Lower limb biomechanics in individuals with knee osteoarthritis before and after total knee arthroplasty surgery. J Arthroplasty 2013; 28:994-9. [PMID: 23523504 DOI: 10.1016/j.arth.2012.10.018] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/03/2012] [Revised: 09/18/2012] [Accepted: 10/17/2012] [Indexed: 02/01/2023] Open
Abstract
We investigated the biomechanical changes that occur in the lower limb following total knee arthroplasty (TKA). Lower limb joint kinematics and kinetics were evaluated in 32 patients before and 12 months following TKA and 28 age-matched controls. Analysis of variance with Bonferroni-adjusted post-hoc tests showed no significant changes in knee joint kinematics and kinetics following TKA despite significant improvements in pain and function. Significant increases in peak ankle plantarflexion and dorsiflexion moments and ankle power generation were observed which may be a compensatory response to impaired knee function to allow sufficient power generation for propulsion. Differences in knee gait parameters may arise as a result of the presence of osteoarthritis and mechanical changes associated with TKA as well as retention of the pre-surgery gait pattern.
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Affiliation(s)
- Pazit Levinger
- Institute of Sport, Exercise and Active Living, Victoria University, Melbourne Vic, Australia
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Creff G, Pichon BP, Blanc C, Maurin D, Sauvajol JL, Carcel C, Moreau JJE, Roy P, Bartlett JR, Man MWC, Bantignies JL. Self-assembly of bridged silsesquioxanes: modulating structural evolution via cooperative covalent and noncovalent interactions. Langmuir 2013; 29:5581-5588. [PMID: 23574041 DOI: 10.1021/la400293k] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [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
The self-assembly of a bis-urea phenylene-bridged silsesquioxane precursor during sol-gel synthesis has been investigated by in situ infrared spectroscopy, optical microscopy, and light scattering. In particular, the evolution of the system as a function of processing time was correlated with covalent interactions associated with increasing polycondensation and noncovalent interactions such as hydrogen bonding. A comprehensive mechanism based on the hydrolysis of the phenylene-bridged organosilane precursor prior to the crystallization of the corresponding bridged silsesquioxane via H-bonding and subsequent irreversible polycondensation is proposed.
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Affiliation(s)
- Gaelle Creff
- Laboratoire Charles Coulomb (UMR CNRS 5521), Université Montpellier 2, Montpellier, France
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Levinger P, Menz HB, Morrow AD, Bartlett JR, Feller JA, Fotoohabadi MR, Bergman NR. Dynamic foot function changes following total knee replacement surgery. Knee 2012; 19:880-5. [PMID: 22672961 DOI: 10.1016/j.knee.2012.05.002] [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] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/29/2011] [Revised: 03/26/2012] [Accepted: 05/13/2012] [Indexed: 02/02/2023]
Abstract
BACKGROUND Individuals with knee osteoarthritis (OA) have flatter/more pronated feet than those without OA, but it is unclear whether altered foot posture and function are a cause or consequence of knee OA. The purpose of this study was to examine whether changes in foot posture and function occur after realignment of the knee following total knee replacement (TKR). MATERIALS AND METHODS Nineteen patients with predominantly medial compartment knee OA were tested prior to and 12 months after TKR. The Foot Posture Index (FPI) and Arch Index (AI) were measured as well as motion of the tibia, rearfoot and forefoot using a 3D motion analysis system incorporating a multisegment foot model. RESULTS There were no significant changes in FPI or AI following TKR, however gait analysis revealed significant increases in tibial external rotation (-18.7 ± 7.0° vs -22.5 ± 8.7°, p=0.002), tibial transverse plane range of motion (-9.1 ± 4.6° vs -11.4 ± 6.1°, p=0.0028) and rearfoot range of motion in the frontal plane (8.6 ± 2.6° vs 10.4 ± 2.7°, p=0.002), and a decrease in rearfoot transverse plane range of motion (8.7 ± 5.3° vs 5.9 ± 4.1°, p=0.038) following the procedure. CONCLUSIONS TKR produces no change in static foot posture, but results in significant changes in rearfoot kinematics during gait. These findings suggest that rearfoot motion compensates for changes in the alignment of the knee, highlighting the ability of the foot to accommodate for proximal skeletal malalignment.
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Affiliation(s)
- Pazit Levinger
- Institute of Sport, Exercise and Active Living, Victoria University, Melbourne VIC 8001, Australia.
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Levinger P, Menz HB, Morrow AD, Perrott MA, Bartlett JR, Feller JA, Bergman NB. Knee biomechanics early after knee replacement surgery predict abnormal gait patterns 12 months postoperatively. J Orthop Res 2012; 30:371-6. [PMID: 21887700 DOI: 10.1002/jor.21545] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/08/2011] [Accepted: 08/11/2011] [Indexed: 02/04/2023]
Abstract
An abnormal flexor moment pattern is often evident following total knee replacement (TKR) surgery. We investigated whether such a pattern at 12 months post-surgery could be predicted using biomechanical gait measures assessed before surgery and at 4 months post-surgery. Thirty two TKR patients were evaluated and classified as normal (biphasic pattern) or abnormal (flexor moment pattern) at each time point. Biomechanical parameters collected before surgery and at 4 months post-surgery were then explored for their ability to predict gait patterns at 12 months post-surgery. The gait pattern at 4 months was significantly associated with the 12 month post-surgery gait pattern, with over half of those with a flexor moment pattern at 4 months retaining this pattern at 12 months. Discriminant function analysis indicated that peak knee flexion during early stance, peak knee extension, and peak knee extension moment at 4 months post-surgery were independent predictors of the gait pattern at 12 months. Thus, an abnormal knee flexor moment pattern at 12 months post-surgery can be predicted by biomechanical analysis 4 months after surgery. Therefore, interventions aimed at improving active extension may need to be implemented early after surgery to restore a normal gait pattern.
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Affiliation(s)
- Pazit Levinger
- Musculoskeletal Research Centre, Faculty of Health Sciences, La Trobe University, Bundoora, Victoria 3086, Australia.
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Levinger P, Lai DTH, Menz HB, Morrow AD, Feller JA, Bartlett JR, Bergman NR, Begg R. Swing limb mechanics and minimum toe clearance in people with knee osteoarthritis. Gait Posture 2012; 35:277-81. [PMID: 22281294 DOI: 10.1016/j.gaitpost.2011.09.020] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/23/2011] [Revised: 09/08/2011] [Accepted: 09/20/2011] [Indexed: 02/02/2023]
Abstract
OBJECTIVE Knee osteoarthritis (OA) has been shown to be a risk factor for falls. Reductions in foot clearance during the swing phase of walking can cause a trip and potentially lead to a fall. This study examined the swing phase mechanics of people with and without knee OA during walking. DESIGN Minimum toe clearance (MTC) height, joint angles at the time of MTC and the influence of the angular changes of the hip, knee and ankle of the swing leg on foot clearance using sensitivity analysis were investigated in 50 knee OA participants and 28 age-matched asymptomatic controls. RESULTS Although both groups had a similar MTC height (controls: 12.8±6.7 mm, knee OA: 13.4±7.0 mm), the knee OA group used a different strategy to achieve the same foot clearance, as evidenced by greater knee flexion (52.5±5.3° vs 49.4±4.8°, p=0.007), greater hip abduction (-3.6±3.3° vs -1.8±3.3°, p=0.03) and less ankle adduction (2.8±1.9° vs 4.2±2.1°, p=0.01). CONCLUSION MTC height was comparable between the groups, however a different swing phase mechanism was used by the knee OA. Although adequate MTC is an important component of safe locomotion, it does not appear to be impaired in people with knee OA. Other factors, such as inadequate responses to postural perturbation, may be responsible for falls in this group.
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Affiliation(s)
- Pazit Levinger
- Musculoskeletal Research Centre, Faculty of Health Sciences, La Trobe University, Bundoora, Victoria 3086, Australia.
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Levinger P, Caldow MK, Feller JA, Bartlett JR, Bergman NR, McKenna MJ, Cameron-Smith D, Levinger I. Association between skeletal muscle inflammatory markers and walking pattern in people with knee osteoarthritis. Arthritis Care Res (Hoboken) 2012; 63:1715-21. [PMID: 21905256 DOI: 10.1002/acr.20625] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
OBJECTIVE Patients with knee osteoarthritis (OA) are characterized by increased muscle inflammation and altered gait. We investigated the association between proinflammatory mediators in the vastus lateralis and physical function and gait in patients with knee OA. METHODS Nineteen patients with knee OA underwent gait analysis, assessment of self-reported pain and physical function (Western Ontario and McMaster Universities Osteoarthritis Index [WOMAC]), and a muscle biopsy that was taken during their knee replacement surgery. Muscle was analyzed for cellular protein inflammatory mediators, interleukin-6, monocyte chemotactic protein 1 (MCP-1), p65 NF-κB, signal transducer and activator of transcription 3 (STAT-3), and JNK-1. Sagittal plane knee function, including early stance knee range of motion (ROM) and knee sagittal plane impulse, was measured using a motion analysis system. Pearson's correlation was used to assess relationships between selected variables. RESULTS Significant positive correlations were found between MCP-1 and self-perceived stiffness, physical function, and the total WOMAC score (P < 0.05). MCP-1 was also negatively correlated with early stance knee ROM (r = -0.52, P = 0.023). Reduced velocity was associated with elevated levels of p65 NF-κB and STAT-3 (P < 0.05). Knee sagittal plane impulse was negatively correlated with JNK-1 (P = 0.02), indicating reduction in knee impulse with an increased level of JNK-1. CONCLUSION Increased levels of several proinflammatory mediators were correlated with altered knee function during walking as well as greater physical disability and slower gait velocity. Identification of the cellular and molecular mechanisms associated with muscle inflammation is important to better understand the underlying mechanism responsible for altered gait and function in patients with knee OA.
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Graffion J, Cojocariu AM, Cattoën X, Ferreira RAS, Fernandes VR, André PS, Carlos LD, Wong Chi Man M, Bartlett JR. Luminescent coatings from bipyridine-based bridged silsesquioxanes containing Eu3+ and Tb3+ salts. ACTA ACUST UNITED AC 2012. [DOI: 10.1039/c2jm31289a] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Levinger I, Levinger P, Trenerry MK, Feller JA, Bartlett JR, Bergman N, McKenna MJ, Cameron-Smith D. Increased inflammatory cytokine expression in the vastus lateralis of patients with knee osteoarthritis. ACTA ACUST UNITED AC 2011; 63:1343-8. [PMID: 21538317 DOI: 10.1002/art.30287] [Citation(s) in RCA: 72] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
OBJECTIVE Increased inflammation and pain are inseparable parts of knee osteoarthritis (OA) that may lead to disuse of the affected limb. The aim of this study was to examine the effects of knee OA on inflammation- and atrophy-related genes and proteins in the vastus lateralis muscle of patients with knee OA. METHODS Nineteen patients with knee OA and 14 asymptomatic control subjects matched for age and body mass index underwent strength measurements and a muscle biopsy. Muscle was analyzed for the total cellular protein of inflammatory kinases (p65 NF-κB, JNK1/2, STAT-3, and suppressor of cytokine signaling 3 [SOCS-3]) and inflammatory intracellular molecules (interleukin-6 [IL-6], IL-8, monocyte chemoattractant protein 1 [MCP-1], tumor necrosis factor α [TNFα], IL-1β, and atrogin-1). RESULTS Knee OA resulted in greater levels of IL-6 protein (34%; P = 0.002). The levels of inflammatory kinases, including STAT-3 (187%; P = 0.002), p65 NF-κB (156%; P = 0.002), and JNK1 (179%; P = 0.027), were also elevated. Furthermore, elevated expression of gene transcripts encoding MCP-1 (28%; P = 0.023), TNFα (85%; P < 0.001), and SOCS-3 (38%; P = 0.055) was observed in patients with knee OA compared with control subjects. Patients with knee OA had reduced muscle strength compared with control subjects (mean ± SEM 84.7 ± 8.7 versus 143.1 ± 20.8 Nm; P = 0.005). Negative correlations were observed between muscle strength and MCP-1 protein abundance (r = -0.37 [P = 0.042]) and the gene expression of TNFα and atrogin-1 messenger RNA (r = -0.46 [P = 0.012] and r = -0.36 [P = 0.040], respectively). CONCLUSION Gene expression and the protein abundance of numerous muscle markers of inflammation and atrophy were elevated in patients with knee OA, and the increase in muscle inflammation was associated with a reduction in muscle strength. Given the role inflammation markers may play in muscle strength and atrophy, further studies are needed to investigate the effect of exercise intervention on skeletal muscle inflammation.
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Levinger P, Menz HB, Fotoohabadi MR, Feller JA, Bartlett JR, Bergman NR. Foot posture in people with medial compartment knee osteoarthritis. J Foot Ankle Res 2010; 3:29. [PMID: 21162748 PMCID: PMC3020154 DOI: 10.1186/1757-1146-3-29] [Citation(s) in RCA: 84] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/13/2010] [Accepted: 12/16/2010] [Indexed: 12/28/2022] Open
Abstract
Background Foot posture has long been considered to contribute to the development of lower limb musculoskeletal conditions as it may alter the mechanical alignment and dynamic function of the lower limb. This study compared foot posture in people with and without medial compartment knee osteoarthritis (OA) using a range of clinical foot measures. The reliability of the foot measures was also assessed. Methods The foot posture of 32 patients with clinically and radiographically-confirmed OA predominantly in the medial compartment of the knee and 28 asymptomatic age-matched healthy controls was investigated using the foot posture index (FPI), vertical navicular height and drop, and the arch index. Independent t tests and effect size (Cohen's d) were used to investigate the differences between the groups in the foot posture measurements. Results Significant differences were found between the control and the knee OA groups in relation to the FPI (1.35 ± 1.43 vs. 2.46 ± 2.18, p = 0.02; d = 0.61, medium effect size), navicular drop (0.02 ± 0.01 vs. 0.03 ± 0.01, p = 0.01; d = 1.02, large effect size) and the arch index (0.22 ± 0.04 vs. 0.26 ± 0.04, p = 0.04; d = 1.02, large effect size). No significant difference was found for vertical navicular height (0.24 ± 0.03 vs. 0.23 ± 0.03, p = 0.54; d = 0.04, negligible effect size). Conclusion People with medial compartment knee OA exhibit a more pronated foot type compared to controls. It is therefore recommended that the assessment of patients with knee OA in clinical practice should include simple foot measures, and that the potential influence of foot structure and function on the efficacy of foot orthoses in the management of medial compartment knee OA be further investigated.
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Affiliation(s)
- Pazit Levinger
- Musculoskeletal Research Centre, Faculty of Health Sciences, La Trobe University, Bundoora, Victoria 3086, Australia.
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Karatchevtseva I, Astoux M, Cassidy DJ, Yee P, Bartlett JR, Griffith CS. Synthesis and characterization of functionalized silica-based nanohybrid materials for oxyanions adsorption. Langmuir 2010; 26:8327-8335. [PMID: 20222724 DOI: 10.1021/la904747m] [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] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
This study investigates the structural evolution of a series of nanohybrid powders and coatings synthesized by direct co-condensation of amino-functionalized alkyltrialkoxysilanes and tetraalkoxysilanes with an aromatic carboxylic acid (trimesic acid, TMA) as a structure directing agent. Fourier transform infrared spectroscopy (FTIR) and (13)C CP-MAS NMR results have suggested the formation of secondary (-CO-NH-) amide linkages upon interaction of TMA with the amino functionalized silane thus creating a "scaffold" around which the silica network is formed and also assisting in more homogeneous distribution of nitrogen sites within the nanohybrid structure. Functionalized silica powders were investigated for their potential to remove toxic oxyanions from mildly acidic or basic solutions. The uptake of Mo(VI), Se(VI), and Cr(VI) oxyanions was investigated as a function of the nanohybrid composition, oxyanion concentration, and solution pH using laser diffraction particle sizing, gas adsorption, and various spectroscopic techniques. The adsorption data obtained for Mo and Se could be adequately described by Langmuir adsorption isotherms, while the Freundlich isotherm is employed to fit the adsorption data for Cr. An easily accessible processing window (of pH, aging time, etc.) has been identified allowing production of continuous and uniform thin nanohybrid coatings on silicon and glass substrates. These coatings were tested as chemical barriers against Mo leaching from specially prepared Mo-doped glass. Leaching studies were conducted over 200 days in water at 90 degrees C and the Mo leaching from coated and uncoated samples compared.
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Affiliation(s)
- Inna Karatchevtseva
- Institute of Materials Engineering, ANSTO, PMB 1, Menai, NSW 2234, Australia.
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Arrachart G, Karatchevtseva I, Cassidy DJ, Triani G, Bartlett JR, Chi Man MW. Synthesis and characterisation of carboxylate-terminated silica nanohybrid powders and thin films. ACTA ACUST UNITED AC 2008. [DOI: 10.1039/b803100b] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Abstract
Silica nanoparticles for controlled release applications have been produced by the reaction of tetramethylorthosilicate (TMOS) inside the water droplets of a water-in-oil microemulsion, under both acidic (pH 1.05) and basic (pH 10.85) conditions. In-situ FTIR measurements show that the addition of TMOS to the microemulsion results in the formation of silica as TMOS, preferentially located in the oil phase, diffuses into the water droplets. Once in the hydrophilic domain, hydrolysis occurs rapidly as a result of the high local concentration of water. Varying the pH of the water droplets from 1.05 to 10.85, however, considerably slows the hydrolysis reaction of TMOS. The formation of a dense silica network occurs rapidly under basic conditions, with IR indicating the slower formation of more disordered silica in acid. SAXS analysis of the evolving particles shows that approximately 11 nm spheres are formed under basic conditions; these are stabilized by a water/surfactant layer on the particle surface during formation. Under acidic conditions, highly uniform approximately 5 nm spheres are formed, which appear to be retained within the water droplets (approximately 6 nm diameter) and form an ordered micelle nanoparticle structure that exhibits sufficient longer-range order to generate a peak in the scattering at q approximately equal to 0.05 A-1. Nitrogen adsorption analysis reveals that high surface area (510 m2/g) particles with an average pore size of 1 nm are formed at pH 1.05. In contrast, base synthesis results in low surface area particles with negligible internal porosity.
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Affiliation(s)
- Kim S Finnie
- Australian Nuclear Science and Technology Organisation, PMB 1, Menai, NSW 2234, Australia.
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Bantignies JL, Vellutini L, Maurin D, Hermet P, Dieudonné P, Wong Chi Man M, Bartlett JR, Bied C, Sauvajol JL, Moreau JJE. Insights into the Self-Directed Structuring of Hybrid Organic−Inorganic Silicas through Infrared Studies. J Phys Chem B 2006; 110:15797-802. [PMID: 16898728 DOI: 10.1021/jp060975r] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.3] [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
Fourier transform infrared (FTIR) spectroscopy has been used to probe the organization of the organic fragments in lamellar bridged silsesquioxanes with organic substructures based on alkylene chains of various lengths and urea groups [O1.5Si(CH2)3NHCONH(CH2)nNHCONH(CH2)3SiO1.5] (n = 6, 8-12). The structure and intermolecular interactions (hydrophobic and H-bonding) of these well-defined self-structured hybrid silicas are discussed in relation to their powder X-ray diffraction patterns. The degree of structural order is determined by the length and parity of the alkylene spacer. A concomitant enhancement in the degree of condensation of the inorganic component and a decrease in the strength of the hydrophobic interactions between the organic components are demonstrated. The strength and directionality of the H-bonding are directly correlated to the crystalllinity of the organic-inorganic hybrid materials.
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Affiliation(s)
- Jean-Louis Bantignies
- Laboratoire des Colloïdes, Verres et Nanomatériaux (UMR CNRS 5587), Université Montpellier II, 34095 Montpellier Cedex 5, France.
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Bartlett JR, DeYoe EA, Doty RW, Lee BB, Lewine JD, Negrão N, Overman WH. Psychophysics of Electrical Stimulation of Striate Cortex in Macaques. J Neurophysiol 2005; 94:3430-42. [PMID: 16079195 DOI: 10.1152/jn.00406.2005] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.8] [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: 11/22/2022] Open
Abstract
Macaques indicated their detection of onset or alteration of 0.2-ms pulses applied in various configurations through electrodes implanted in striate cortex. When microelectrodes were introduced and left in place, the threshold for detection of 100-Hz pulses nearly doubled within 24 h. However, for chronically implanted platinum-alloy macroelectrodes detection thresholds usually remained stable for many months, independently of location within striate cortex or its immediately subjacent white matter. Thresholds were unaffected by the visual conditions, such as light versus darkness, or movement of the eyes; but in one animal blind after acute glaucoma thresholds for loci in striate cortex were permanently decreased by about 50%. Learning to respond to electrical stimulation of the optic tract produced no tendency to respond to such stimulation of striate cortex. Onset of stimulation at a given locus could be detected even in the face of continuous supraliminal stimulation at four surrounding loci on a 3-mm radius. The surround stimulation did alter the threshold of the central locus, but such stimuli could not summate if they were subliminal by some 10%. Cessation of stimulation that had been continuing for 1 min to 1 h could be detected if it were being applied at a level 20–75% above that needed for detection of stimulus onset. Continuous stimulation had a pronounced “priming” effect, in that modulation of frequency or intensity of such stimulation by as little as 5% could be detected (e.g., 20 μA in a background of 500 μA, or <2-ms interpulse interval with pulses at 50 Hz). Using pulses inserted in various phase relations to ongoing pulses at 2–5 Hz, it could be determined that stimulus pulses were surrounded by a strong facilitatory period for about 30 ms, which was then replaced by refractoriness. Given the congruence of macaque and human visual anatomy and psychophysics, these results further encourage efforts to develop a cortical prosthesis for the blind.
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Affiliation(s)
- John R Bartlett
- Department of Neurobiology and Anatomy, Box 603, University of Rochester Medical Center, Rochester, NY 14642, USA
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Taylor AP, Finnie KS, Bartlett JR, Holden PJ. Quantification of the contribution of surface outgrowth to biocatalysis in sol-gels: oxytetracycline production by Streptomyces rimosus. Biotechnol Lett 2004; 26:1707-11. [PMID: 15604823 DOI: 10.1007/s10529-004-3740-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 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] [Indexed: 11/29/2022]
Abstract
A technique was developed for differentiating the activity of microbes solely within sol gels by using the contribution of biomass outgrowth. Streptomyces rimosus was immobilised in colloidal silica gels and biomass growth, oxytetracycline synthesis, pH and carbohydrate consumption were compared for UV surface-sterilised gels, untreated gels, and liquid cultures. Absolute and biomass specific oxytetracycline yields were higher for non-sterile gels than for liquid culture. Biomass solely within colloidal silica gels (1.7 mg ml(-1)), and gels obtained from colloidal silica modified by addition of larger silica particles (1.2 mg ml(-1)) yielded 27 and 21 microg ml(-1) oxytetracycline compared with 97 and 104 microg ml(-1) for unsterilised gels (3.6 and 5.2 mg ml(-1) biomass) displaying outgrowth. It was therefore apparent that biomass and antibiotic production within the gels was limited and that optimisation requires gel modification.
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Affiliation(s)
- Anthony P Taylor
- Australian Nuclear Science and Technology Organisation (ANSTO), Lucas Heights, Sydney, Australia.
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Abstract
Male broilers were used to evaluate the effect of zinc on performance and immune competence during heat stress (HS). Broilers raised in either a thermoneutral (TN, 23.9 degrees C constant) or HS (23.9 to 35 degrees C cycling) environment were fed a low zinc diet (LZ; 34 mg/kg), an adequate zinc diet (AZ; 68 mg/kg), or a supplemental zinc diet (HZ; 181 mg/kg). Humoral immunity was assessed by intravenous injection of 7% SRBC followed by evaluation of serum for antibody titers in primary and secondary responses. Cell-mediated immunity was assessed using a Sephadex stimulation method to recruit abdominal exudate cells (AEC) to evaluate macrophage phagocytic ability. The HS birds consumed 12.5% less feed, gained 24.6% less weight, and had lower feed efficiency when compared to TN birds. Dietary zinc levels did not impact growth performance or plasma zinc concentration. Numbers of AEC, macrophages in AEC, phagocytic macrophages, and internalized opsonized and unopsonized SRBC were increased by HZ. Total, IgM, and IgG antibody titers for primary and secondary responses were significantly increased in birds receiving HZ under TN conditions. Tibia zinc concentration increased with increasing zinc levels but did not change with temperature. Lymphoid organ weights, primary and secondary antibody responses, incidences of macrophages in AEC, phagocytic ability of macrophages, and plasma zinc concentration were all significantly reduced by HS. These results indicate that the immune response of broilers can be influenced by the level of zinc in the diet and by environmental conditions.
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Affiliation(s)
- J R Bartlett
- Department of Animal Science, The University of Tennessee, Knoxville, Tennessee 37996-4500, USA.
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Martens WN, Kloprogge JT, Frost RL, Bartlett JR. A Crystallite Packing Model for Pseudoboehmite Formed during the Hydrolysis of Trisecbutoxyaluminium to Explain the Peptizability. J Colloid Interface Sci 2002; 247:132-7. [PMID: 16290448 DOI: 10.1006/jcis.2001.8079] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2001] [Accepted: 10/29/2001] [Indexed: 11/22/2022]
Abstract
A model for pseudoboehmite crystallite packing formed during the hydrolysis of trisecbutoxyaluminium is postulated. The model describes platelike crystallites of pseudoboehmite stacked in a sharing edges only configuration. With this type of stacking, the pore sizes detected are approximately equal to the crystallite sizes of the hydrolysates. The hydrolysates age via a dissolution re-precipitation reaction. This increases the size of the crystallite size of the pseudoboehmite formed, speeding peptization by allowing nitrate ions to enter pores and access the surfaces of the crystallites. This type of model also allows an explanation for the peptization kinetics of systems containing sec-butanol formed during the hydrolysis of trisecbutoxyaluminium.
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Affiliation(s)
- Wayde N Martens
- Centre for Instrumental and Developmental Chemistry, Queensland University of Technology, GPO Box 2434, 2 George Street, Brisbane, Queensland, 4001, Australia.
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Abstract
After providing an overview of depression this article briefly reviews the development of psychosurgery and outlines the current procedures in use world wide. Stereotactic subcaudate tractotomy (SST) is described in particular detail, and the rationale for its use in the treatment of resistant depression is then discussed by considering the findings of neuropsychological, neurophysiological and neuroimaging studies. The emerging evidence suggests that the prefrontal cortex subserves an essential function in emotion and that disruption of its connections modifies mood.
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Affiliation(s)
- G S Malhi
- Mood Disorders Unit, University Department of Psychiatry, Prince of Wales Hospital, High Street, Randwick, Sydney, NSW 2031, Australia.
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Abstract
BACKGROUND/AIMS The visual loss associated with compression of the optic chiasm by pituitary tumours may be transient or permanent, possibly related to the extent of irreversible retrograde degeneration to the retinal ganglion cells. The pattern electroretinogram (PERG) N95 component is thought to rise in relation to retinal ganglion cell function and hence may be a potential prognostic indicator for visual function following decompressive surgery. METHODS The notes and electrodiagnostic records of 72 eyes from 36 patients with chiasmal compression were retrospectively analysed. RESULTS The postoperative change in visual field was found to be associated with the PERG N95:P50 ratio (p=0.01). Improvement in visual field was shown by a greater proportion of eyes with a normal N95:P50 ratio (65%) than with an abnormal ratio (27%). No change in visual field occurred in 26% of the eyes with a normal N95:P50 ratio compared with 67% of those with an abnormal ratio. Only 8% of eyes showed a worsening of visual field following surgery, in similar proportions for eyes with normal and abnormal N95:P50 ratios. There was no significant relationship with visual acuity. CONCLUSION The PERG is a useful visual prognostic indicator in the preoperative assessment of chiasmal compression.
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Affiliation(s)
- D N Parmar
- Department of Neurosciences, King's College Hospital, London SE5 9RS, UK
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Finnie KS, Luca V, Moran PD, Bartlett JR, Woolfrey JL. Vibrational spectroscopy and EXAFS study of Ti(OC2H5)4 and alcohol exchange in Ti(iso-OC3H7)4. ACTA ACUST UNITED AC 2000. [DOI: 10.1039/a906662d] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Abstract
Demonstration of fluid levels on MRI is well recognised in cerebral haematomas, tumours and cysts. The occurrence of fluid levels within haemorrhagic pituitary tumours has not previously been described in detail. Evidence of haemorrhage was identified in 27 of 125 pituitary tumours. Fluid levels occurred in 13 of these haemorrhagic tumours. No association with histological type was identified. Recognised risk factors for haemorrhage were identified in half of the cases.
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Affiliation(s)
- R K Lenthall
- Department of Neuroimaging, King's College Hospital, London, UK
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Percy MJ, Bartlett JR, Woolfrey JL, Spiccia L, West BO. The influence of β-diketones on the induction times for hydrolysis of zirconium(IV) alkoxides. ACTA ACUST UNITED AC 1999. [DOI: 10.1039/a806782a] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Abstract
The long-term outcome of 78 patients with spinal meningiomas operated on over 20 years at a single neurosurgical unit was analysed. Age, sex and tumour location were similar to those reported by others. Overall, 95% of our patents were independently mobile postoperatively, despite 25% of the group being unable to walk before operation, including four paraplegic patients. Only two tumours were entirely extradural, and a further two were both intra- and extradural. In all cases, tumour exposure was by posterior laminectomy, without recourse to more complex approaches. Complete tumour resection was achieved in 77 (98%) of cases. The dural attachment was excised in 20 cases and diathermy was applied in 58. There was one recurrence, 14 years after the original surgery. Complex and technically challenging surgical approaches are unnecessary to obtain complete removal even for anteriorly placed tumours. Excision of the dural base would seem unnecessary to attain a low recurrence rate.
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Affiliation(s)
- A T King
- Department of Neurosurgery, Kings College Hospital, London, UK
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Abstract
The psychosurgical treatment of psychiatric illnesses, using stereotactic subcaudate tractotomy (SST), has been carried out at the Geoffrey Knight Unit since 1961. Recently, the procedure has had to be modified. This paper describes the manner in which this has been achieved and the clinical implications of this change.
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Affiliation(s)
- G S Malhi
- Geoffrey Knight Unit, Maudsley Hospital, London, UK
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Moran PD, Bowmaker GA, Cooney RP, Finnie KS, Bartlett JR, Woolfrey JL. Vibrational Spectra and Molecular Association of Titanium Tetraisopropoxide. Inorg Chem 1998; 37:2741-2748. [PMID: 11670410 DOI: 10.1021/ic9709436] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The Fourier transform-infrared (FT-IR) and polarized FT-Raman spectra of titanium tetraisopropoxide (tetraisopropoxytitanium, TPT), in pure and diluted forms, and of 2-propanol have been investigated in conjunction with previous assignments for related compounds to obtain a comprehensive assignment of the vibrational spectra. Evidence was obtained for the presence of both monomeric and associated species of TPT. The latter are formed by coordination expansion through bridging isopropoxy ligands. For both monomeric and associated TPT species, vibrational modes of isopropoxy ligands with nu(C-O) mode character were coupled to nu(s)(Ti-O) and nu(as)(Ti-O) modes (interligand coupling). The symmetrically coupled ligand modes gave rise to intense, strongly polarized bands in the Raman spectrum. The antisymmetrically coupled ligand modes gave rise to strong bands in the IR spectrum at lower wavenumbers than the corresponding Raman bands. Molecular association of TPT produced negligible shifts in the ligand modes coupled to the nu(s)(Ti-O) mode in the Raman spectrum. In contrast, the degeneracy of the strong ligand modes coupled to the nu(as)(Ti-O) mode was lifted upon molecular association, yielding band shifts and splittings in the IR spectrum of neat TPT.
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Affiliation(s)
- Paul D. Moran
- Materials Division, Australian Nuclear Science and Technology Organisation, Private Mail Bag 1, Menai, NSW 2234, Australia
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Moran PD, Rickard CEF, Bowmaker GA, Cooney RP, Bartlett JR, Woolfrey JL. X-ray Structure and Raman Spectrum of [Ti(4)(&mgr;(3)-O)(2)(&mgr;(2)-O(i)()Pr)(2)(O(i)()Pr)(8)(acac)(2)]: Presence of a Ti(4)(&mgr;(3)-O)(2)(&mgr;(2)-O(i)()Pr)(2) Ladder-like Core. Inorg Chem 1998; 37:1417-1419. [PMID: 11670355 DOI: 10.1021/ic970942d] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.9] [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)
- Paul D. Moran
- Materials Division, Australian Nuclear Science and Technology Organization, Private Mail Bag 1, Menai, NSW 2234, Australia
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Siderov J, Bartlett JR, Madigan CJ. Pupillary dilation: the patient's perspective. Clin Exp Optom 1996. [DOI: 10.1111/j.1444-0938.1996.tb04976.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Affiliation(s)
- John Siderov
- *Clinic Research Unit, Victorian College of Optometry
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Evans BM, Bartlett JR. Prediction of outcome in severe head injury based on recognition of sleep related activity in the polygraphic electroencephalogram. J Neurol Neurosurg Psychiatry 1995; 59:17-25. [PMID: 7608703 PMCID: PMC1073595 DOI: 10.1136/jnnp.59.1.17] [Citation(s) in RCA: 63] [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] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
This study shows that the continuing presence of activity similar to normal sleep in the EEG in conjunction with the EEG polygraph (EEGP) can be used to determine the severity of brain damage after head injury. Recordings were taken within seven days of head injury from 154 unselected patients after resuscitation and emergency surgery. Sixteen patients with ongoing seizures were excluded. In the remaining 138 patients the presence of activity in the EEG, EEGP, or both, which can also be recognised in normal alertness and sleep, was noted. Particular attention was paid to the presence or absence of arousal related phasic activity involving EEG, motor, and autonomic changes. The traces were allocated to one of five groups: group 1, wakeful traces with normal alpha in at least one hemisphere; group 2, sleep-like traces with K complexes responsive to stimulation; group 3, traces with phasic activity related to abnormal spontaneous arousal including EEG changes; group 4, traces with abnormal spontaneous arousal activity without EEG changes; group 5, traces with no spontaneous arousal activity. The mean follow up was 21.5 months. Groups 2 and 3 were significantly associated with a good outcome and group 5 with death or a vegetative state. Comparison between the EEG/EEGP findings and the Glasgow coma scale at the time of the recording showed the EEG/EEGP to be the better predictor of outcome, particularly for individual patients.
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Affiliation(s)
- B M Evans
- Regional Department of Clinical Neurophysiology, Brook General Hospital, London, UK
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