The Experts below are selected from a list of 60027 Experts worldwide ranked by ideXlab platform
Anthony P Russell - One of the best experts on this subject based on the ideXlab platform.
-
2002 Integrative functional morphology of the gekkotan adhesive system (Reptilia: Gekkota). Integr
2015Co-Authors: Anthony P RussellAbstract:SYNOPSIS. Climbing assisted by adhesive subdigital pads in gekkotan lizards has been the subject of intrigue and study for centuries. Many hypotheses have been advanced to explain the Mechanism of Adhesion, and recently this phenomenon has been investigated at the level of individual setae. The ability to isolate, ma-nipulate and record adhesive forces from individual setae has provided new insights, not only into the Mechanism of attachment, but also into the physical orientation of these structures necessary to establish attachment, maximize adhesive force, and effect subsequent release. This, in turn, has enabled a reassessment of the overall morphology and mode of operation of the adhesive system. Digital hyperextension has often been noted as a behavioral characteristic associated with the deployment of the gekkotan adhesive system— this is now understandable in the context of setal attachment and release kinematics, and in the context of the evolution of this pattern of digital movement from the primitive pattern of saurian digital kinematics. The perpendicular and parallel preloads associated with setal attachment are now reconcilable with other morphological aspects of the gekkotan adhesive system—the lateral digital tendon complex and the vascular sinus network, respectively. Future investigations of the integrated adhesive system will help to further elucidate the interdependence of its structural and functional components
-
integrative functional morphology of the gekkotan adhesive system reptilia gekkota
Integrative and Comparative Biology, 2002Co-Authors: Anthony P RussellAbstract:Climbing assisted by adhesive subdigital pads in gekkotan lizards has been the subject of intrigue and study for centuries. Many hypotheses have been advanced to explain the Mechanism of Adhesion, and recently this phenomenon has been investigated at the level of individual setae. The ability to isolate, manipulate and record adhesive forces from individual setae has provided new insights, not only into the Mechanism of attachment, but also into the physical orientation of these structures necessary to establish attachment, maximize adhesive force, and effect subsequent release. This, in turn, has enabled a reassessment of the overall morphology and mode of operation of the adhesive system. Digital hyperextension has often been noted as a behavioral characteristic associated with the deployment of the gekkotan adhesive system-this is now understandable in the context of setal attachment and release kinematics, and in the context of the evolution of this pattern of digital movement from the primitive pattern of saurian digital kinematics. The perpendicular and parallel preloads associated with setal attachment are now reconcilable with other morphological aspects of the gekkotan adhesive system-the lateral digital tendon complex and the vascular sinus network, respectively. Future investigations of the integrated adhesive system will help to further elucidate the interdependence of its structural and functional components.
Huaiyu Wang - One of the best experts on this subject based on the ideXlab platform.
-
enhanced interfacial Adhesion and osseointegration of anodic tio2 nanotube arrays on ultra fine grained titanium and underlying Mechanisms
Acta Biomaterialia, 2020Co-Authors: Lingxia Xie, Shahir Yasin Bin Mohd Yusuf, Nong Gao, M J Starink, Liping Tong, Paul K Chu, Huaiyu WangAbstract:Abstract The poor Adhesion of anodic TiO2 nanotubes (TNTs) arrays on titanium (Ti) substrates adversely affects applications in many fields especially biomedical engineering. Herein, an efficient strategy is described to improve the Adhesion strength of TNTs by performing grain refinement in the underlying Ti substrate via high-pressure torsion processing, as a larger number of grain boundaries can provide more interfacial mechanical anchorage. This process also improves the biocompatibility and osseointegration of TNTs by increasing the surface elastic modulus. The TNTs in length of 0.4 µm have significantly larger Adhesion strength than the 2.0 µm long ones because the shorter TNTs experience less interfacial internal stress. However, post-anodization annealing reduces the fluorine concentration in TNTs and Adhesion strength due to the formation of interfacial cavities during crystallization. The interfacial structure of TNTs/Ti system and the Mechanism of Adhesion failures are further investigated and discussed. Statement of Significance Self-assembled TiO2 nanotubes (TNTs) prepared by electrochemical anodization have a distinct morphology and superior properties, which are commonly used in photocatalytic systems, electronic devices, solar cells, sensors, as well as biomedical implants. However, the poor Adhesion between the TNTs and Ti substrate has hampered wider applications. Here in this study, we describe an efficient strategy to improve the Adhesion strength of TNTs by performing grain refinement in the underlying Ti substrate via high-pressure torsion (HPT) processing. The interfacial structure of TNTs/Ti system and the Mechanism of Adhesion failure are systematically studied and discussed. Our findings not only develop the knowledge of TNTs/Ti system, but also provide new insights into the design of Ti-based implants for orthopedic applications.
-
enhanced interfacial Adhesion and osseointegration of anodic tio 2 nanotube arrays on ultra fine grained titanium and underlying Mechanisms
Social Science Research Network, 2020Co-Authors: Lingxia Xie, Nong Gao, M J Starink, Liping Tong, Paul K Chu, Shahir Mohd Yusuf, Huaiyu WangAbstract:The poor Adhesion of anodic TiO2 nanotubes (TNTs) arrays on Ti substrates adversely affects applications in many fields especially biomedical engineering. Herein, we describe an efficient strategy to improve the Adhesion strength of TNTs by performing grain refinement in the underlying Ti substrate via high-pressure torsion processing, as a larger number of grain boundaries can provide more interfacial mechanical anchorage. This process also improves the biocompatibility and osseointegration of TNTs by increasing the surface elastic modulus. The TNTs in length of 0.4 μm have significantly larger Adhesion strength than the 2.0 μm long ones because the shorter TNTs experience less interfacial internal stress. However, post-anodization annealing reduces the F concentration in TNTs and Adhesion strength due to the formation of interfacial cavities during crystallization. The interfacial structure of TNTs/Ti system and the Mechanism of Adhesion failures are further investigated and discussed.
Josee Chabot - One of the best experts on this subject based on the ideXlab platform.
-
deacetylation of fungal exopolysaccharide mediates Adhesion and biofilm formation
Mbio, 2016Co-Authors: Alexander M Geller, Natalie C. Bamford, Brendan D. Snarr, Fabrice N Gravelat, Francois Le Mauff, Josee ChabotAbstract:ABSTRACT The mold Aspergillus fumigatus causes invasive infection in immunocompromised patients. Recently, galactosaminogalactan (GAG), an exopolysaccharide composed of galactose and N -acetylgalactosamine (GalNAc), was identified as a virulence factor required for biofilm formation. The molecular Mechanisms underlying GAG biosynthesis and GAG-mediated biofilm formation were unknown. We identified a cluster of five coregulated genes that were dysregulated in GAG-deficient mutants and whose gene products share functional similarity with proteins that mediate the synthesis of the bacterial biofilm exopolysaccharide poly-(β1-6)- N -acetyl-d-glucosamine (PNAG). Bioinformatic analyses suggested that the GAG cluster gene agd3 encodes a protein containing a deacetylase domain. Because deacetylation of N -acetylglucosamine residues is critical for the function of PNAG, we investigated the role of GAG deacetylation in fungal biofilm formation. Agd3 was found to mediate deacetylation of GalNAc residues within GAG and render the polysaccharide polycationic. As with PNAG, deacetylation is required for the adherence of GAG to hyphae and for biofilm formation. Growth of the Δ agd3 mutant in the presence of culture supernatants of the GAG-deficient Δ uge3 mutant rescued the biofilm defect of the Δ agd3 mutant and restored the adhesive properties of GAG, suggesting that deacetylation is an extracellular process. The GAG biosynthetic gene cluster is present in the genomes of members of the Pezizomycotina subphylum of the Ascomycota including a number of plant-pathogenic fungi and a single basidiomycete species, Trichosporon asahii , likely a result of recent horizontal gene transfer. The current study demonstrates that the production of cationic, deacetylated exopolysaccharides is a strategy used by both fungi and bacteria for biofilm formation. IMPORTANCE This study sheds light on the biosynthetic pathways governing the synthesis of galactosaminogalactan (GAG), which plays a key role in A. fumigatus virulence and biofilm formation. We find that bacteria and fungi use similar strategies to synthesize adhesive biofilm exopolysaccharides. The presence of orthologs of the GAG biosynthetic gene clusters in multiple fungi suggests that this exopolysaccharide may also be important in the virulence of other fungal pathogens. Further, these studies establish a molecular Mechanism of Adhesion in which GAG interacts via charge-charge interactions to bind to both fungal hyphae and other substrates. Finally, the importance of deacetylation in the synthesis of functional GAG and the extracellular localization of this process suggest that inhibition of deacetylation may be an attractive target for the development of novel antifungal therapies.
Pauline S Handley - One of the best experts on this subject based on the ideXlab platform.
-
plasticizers increase Adhesion of the deteriogenic fungus aureobasidium pullulans to polyvinyl chloride
Applied and Environmental Microbiology, 1999Co-Authors: Jeremy S Webb, Marianne Nixon, I M Eastwood, Malcolm Greenhalgh, S J Read, Geoffrey D Robson, Pauline S HandleyAbstract:Initial Adhesion of fungi to plasticized polyvinyl chloride (pPVC) may determine subsequent colonization and biodeterioration processes. The deteriogenic fungus Aureobasidium pullulans was used to investigate the physicochemical nature of Adhesion to both unplasticized PVC (uPVC) and pPVC containing the plasticizers dioctyl phthalate (DOP) and dioctyl adipate (DOA). A quantitative Adhesion assay using image analysis identified fundamental differences in the Mechanism of Adhesion of A. pullulans blastospores to these substrata. Adhesion to pPVC was greater than that to uPVC by a maximum of 280% after a 4-h incubation with 10(8) blastospores ml(-1). That plasticizers enhance Adhesion to PVC was confirmed by incorporating a dispersion of both DOA and DOP into the blastospore suspension. Adhesion to uPVC was increased by up to 308% in the presence of the dispersed plasticizers. Hydrophobic interactions were found to dominate Adhesion to uPVC because (i) a strong positive correlation was observed between substratum hydrophobicity (measured by using a dynamic contact angle analyzer) and Adhesion to a range of unplasticized polymers including uPVC, and (ii) neither the pH nor the electrolyte concentration of the suspension buffer, both of which influence electrostatic interactions, affected Adhesion to uPVC. In contrast, Adhesion to pPVC is principally controlled by electrostatic interactions. Enhanced Adhesion to pPVC occurred despite a relative reduction of 13 degrees in the water contact angle of pPVC compared to that of uPVC. Furthermore, Adhesion to pPVC was strongly dependent on both the pH and electrolyte concentration of the suspension medium, reaching maximum levels at pH 8 and with an electrolyte concentration of 10 mM NaCl. Plasticization with DOP and DOA therefore increases Adhesion of A. pullulans blastospores to pPVC through an interaction mediated by electrostatic forces.
Lingxia Xie - One of the best experts on this subject based on the ideXlab platform.
-
enhanced interfacial Adhesion and osseointegration of anodic tio2 nanotube arrays on ultra fine grained titanium and underlying Mechanisms
Acta Biomaterialia, 2020Co-Authors: Lingxia Xie, Shahir Yasin Bin Mohd Yusuf, Nong Gao, M J Starink, Liping Tong, Paul K Chu, Huaiyu WangAbstract:Abstract The poor Adhesion of anodic TiO2 nanotubes (TNTs) arrays on titanium (Ti) substrates adversely affects applications in many fields especially biomedical engineering. Herein, an efficient strategy is described to improve the Adhesion strength of TNTs by performing grain refinement in the underlying Ti substrate via high-pressure torsion processing, as a larger number of grain boundaries can provide more interfacial mechanical anchorage. This process also improves the biocompatibility and osseointegration of TNTs by increasing the surface elastic modulus. The TNTs in length of 0.4 µm have significantly larger Adhesion strength than the 2.0 µm long ones because the shorter TNTs experience less interfacial internal stress. However, post-anodization annealing reduces the fluorine concentration in TNTs and Adhesion strength due to the formation of interfacial cavities during crystallization. The interfacial structure of TNTs/Ti system and the Mechanism of Adhesion failures are further investigated and discussed. Statement of Significance Self-assembled TiO2 nanotubes (TNTs) prepared by electrochemical anodization have a distinct morphology and superior properties, which are commonly used in photocatalytic systems, electronic devices, solar cells, sensors, as well as biomedical implants. However, the poor Adhesion between the TNTs and Ti substrate has hampered wider applications. Here in this study, we describe an efficient strategy to improve the Adhesion strength of TNTs by performing grain refinement in the underlying Ti substrate via high-pressure torsion (HPT) processing. The interfacial structure of TNTs/Ti system and the Mechanism of Adhesion failure are systematically studied and discussed. Our findings not only develop the knowledge of TNTs/Ti system, but also provide new insights into the design of Ti-based implants for orthopedic applications.
-
enhanced interfacial Adhesion and osseointegration of anodic tio 2 nanotube arrays on ultra fine grained titanium and underlying Mechanisms
Social Science Research Network, 2020Co-Authors: Lingxia Xie, Nong Gao, M J Starink, Liping Tong, Paul K Chu, Shahir Mohd Yusuf, Huaiyu WangAbstract:The poor Adhesion of anodic TiO2 nanotubes (TNTs) arrays on Ti substrates adversely affects applications in many fields especially biomedical engineering. Herein, we describe an efficient strategy to improve the Adhesion strength of TNTs by performing grain refinement in the underlying Ti substrate via high-pressure torsion processing, as a larger number of grain boundaries can provide more interfacial mechanical anchorage. This process also improves the biocompatibility and osseointegration of TNTs by increasing the surface elastic modulus. The TNTs in length of 0.4 μm have significantly larger Adhesion strength than the 2.0 μm long ones because the shorter TNTs experience less interfacial internal stress. However, post-anodization annealing reduces the F concentration in TNTs and Adhesion strength due to the formation of interfacial cavities during crystallization. The interfacial structure of TNTs/Ti system and the Mechanism of Adhesion failures are further investigated and discussed.