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Do tensile and shear forces exerted on cells influence mechanotransduction through stored energy considerations?

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BIOCELL 2024年第4期48卷 525-540页

作者： frederick h.silver TANMAY DEShMUKh Department of Pathology and Laboratory Medicine Robert Wood Johnson Medical SchoolRutgersThe State University of New JerseyPiscatawayNJ 08854USA OptoVibronex LLC.Ben Franklin Tech PartnersBethlehemPA 18015USA

All tissues in the body are subjected externally to gravity and internally by collagenﬁbril and cellular retractive forces that create stress and energy equilibrium required for *** involves mechanical work(force through a distance)and energy storage as kinetic and potential *** leads to changes in cell mitosis or apoptosis and the synthesis or loss of tissue *** involves the application of energy directly to cells through integrin-mediated processes,cell-cell connections,stretching of the cell cytoplasm,and activation of the cell nucleus via yes-associated protein(YAP)and transcriptional coactivator with PDZ-motif(TAZ).These processes involve numerous complexes,intermediate molecules,and multiple *** pathways have been identiﬁed from research studies on vertebrate cell culture and from studies in *** pathways involve mechanosensors and other molecules that activate the *** review discusses the mitogen-activated protein kinase(MAPK)family,hippo,hedgehog,and Wingless-related integration site(WNT)/βcatenin signaling *** mediators covered includeβcatenin,ion channels,growth factors,hormone receptors,members of the Ras superfamily,and components of the linker of nucleoskeleton and cytoskeleton(LINC)***,the interrelationship among the different pathways remains to be clariﬁ***-mediated mechanotransduction involves direct tensile loading and energy applied to the cell membrane via collagenﬁbril *** energy is transferred between cells by stretching the cell-cell connections involving cadherins and the WNT/βcatenin *** alterations induce changes in intracellular events in the cytoskeleton and nuclear skeleton caused by the release of YAP and *** coactivators then penetrate through the nuclear pores and inﬂuence nuclear cell *** in the balance of forces and energy applied to cells and tissues is hypothesized to shift th

关键词： MAPK family hippo hedgehog WNT pathway βcatenin Ion channels Growth factor receptors hormone receptors Ras superfamily LINC complex Collagen Cadherins

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生物材料科学与生物相容性

国外科技新书评介 2013年第9期 9-10页

作者： frederick h.silver() 魏玉保不详中国科学院遗传与发育生物学研究所

生物相容性（或免疫排斥）从19世纪输血反应的发现就开始引起了生理学家和免疫学家的关注，但生物材料的生物相容性成为研究热点还是从上世纪90年代开始。作者在过去的15年中一直在新泽西州立大学医学院讲授生物“高分子材料”和“病理... 详细信息

生物相容性（或免疫排斥）从19世纪输血反应的发现就开始引起了生理学家和免疫学家的关注，但生物材料的生物相容性成为研究热点还是从上世纪90年代开始。作者在过去的15年中一直在新泽西州立大学医学院讲授生物“高分子材料”和“病理生物学”两门课程，本书基于课程讲稿写就。

关键词：生物相容性材料科学高分子材料生理学家输血反应免疫排斥生物材料州立大学

Biochemical, Biophysical and Mechanical Characterization of Decellularized Dermal Implants

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Materials Sciences and Applications 2017年第12期8卷 873-888页

作者： frederick h. silver Dale DeVore Ruchit Shah Department of Pathology and Laboratory Medicine Robert Wood Johnson Medical School Rutgers the State University of New Jersey Piscataway NJ USA DV Consulting Services Chelmsford MA USA Graduate Program in Biomedical Engineering Rutgers the State University of New Jersey Piscataway NJ USA

Allografts have been used in a variety of applications to augment as well as replace tissues throughout the body. A number of steps are involved in selection, harvesting, processing and testing of dermal allografts. Grafts can be obtained that are: free of antibodies to viruses and low in viral titers. Cellular material can be eliminated from the tissue and the product becomes almost exclusively a collagen fiber network. The purpose of this paper is to examine the changes in collagen structure and properties that occur during processing of decellularized dermis. The results indicate that collagen fiber swelling occurs during processing although the product preserves the native collagen banding pattern at the fibrillar structural level. Fiber swelling and decreased collagen deformability of processed dermis, may lead to stress concentration at the implant-tissue interface and up-regulation of mechanotransduction. This may lead to premature mechanical failure due to creation of a chronic inflammatory condition at the implant-tissue interface. It is suggested that all dermal allografts be oriented such that Langer’s lines of the implant match those of the host tissue, and that wound closure by suturing be done under conditions that preserve the normal tension in skin in order to minimize implant-interfacial failure.

关键词： Collagen Dermis Repair Wound healing Optical Coherence Tomography Vibrational Analysis Resonant Frequency Modulus Langer’s Lines Mechanotransduction

Mechanical Analysis of Multi-Component Tissues

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World Journal of Mechanics 2017年第4期7卷 121-132页

作者： frederick h. silver Ruchit G. Shah Department of Pathology and Laboratory Medicine Robert Wood Johnson Medical School Rutgers The State University of New Jersey Piscataway USA Graduate Program in Biomedical Engineering Rutgers The State University of New Jersey Piscataway USA

Collagen is the major structural fiber found in mammalian tissues. It is a protein in the form of a triple-helix which is found in several subfamilies, the most abundant of which is the fiber forming group containing Types I, II and III. Type I collagen is found in tendons, skin, cornea, bone, lung and vessel walls. This collagen is thought to give rise to the high tensile strengths of collagen fibers in tissues;in addition, it is actively involved in other physiologic processes such mechanotransduction. however, the non-linear mechanical behavior and viscoelasticity of collagen fibers make analysis of the mechanical properties of tissues complicated. Mechanistically, during mechanical loading, a tensional increase in the D period is observed with increasing strain that is associated with: 1) molecular elongation at the triple-helical level of structure;2) increases in the gap distance between the end of one triple-helix and the start of the next one in the microfibril;and 3) molecular slippage. In this paper, we discuss the relationship between collagen hierarchical structure and its non-linear mechanical properties. Using vibrational analysis and optical coherence tomography, it is hoped that the mechanical properties of collagenous tissues can be studied in vivo in order to better understand tissue mechanics and to be better able to offer early diagnosis and differentiation of different disease states.

关键词： Collagen Fibers Mechanical Properties Optical Coherence Tomography Vibrational Analysis Tendon Skin Cartilage Elastic Arteries

Analysis of Mechanical Behavior of Composite Tissues Using Vibrational Optical Coherence Tomography

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World Journal of Mechanics 2017年第10期7卷 271-282页

作者： frederick h. silver Ruchit G. Shah Department of Pathology and Laboratory Medicine Robert Wood Johnson Medical School Rutgers The State University of New Jersey Piscataway NJ USA Graduate Program in Biomedical Engineering Rutgers The State University of New Jersey Piscataway NJ USA

Extracellular matrices (ECMs) found in vertebrate tissues are fiber reinforced composite materials that prevent premature mechanical failure, store, transmit, and dissipate mechanical energy generated by the musculoskeletal system. We have developed a new method using optical cohesion tomography and vibrational analysis to non-destructively and non-invasively measure the mechanical properties of composite tissues and polymeric materials. In addition, this method can be used to measure the moduli of individual components of composite materials and perform “mechanical spectroscopy” on materials. In addition, we propose that measurement of the resonant frequency of a material minimizes the viscoelastic behavior of a composite material. This approach simplifies the analysis of mechanical behavior of polymers and others materials that demonstrate time-dependence to their properties.

关键词： Collagen Fibers Elastic Fibers Dermis Mechanical Properties Optical Coherence Tomography Vibrational Analysis Skin Cartilage Bone Composites

Non-Invasive and Non-Destructive Determination of Corneal and Scleral Biomechanics Using Vibrational Optical Coherence Tomography: Preliminary Observations

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Materials Sciences and Applications 2018年第7期9卷 657-669页

作者： frederick h. silver Ruchit G. Shah Dominick Benedetto Department of Pathology and Laboratory Medicine Robert Wood Johnson Medical School Rutgers The State University of New Jersey Piscataway NJ USA Graduate Program in Biomedical Engineering Rutgers The State University of New Jersey Piscataway NJ USA Morristown Ophthalmology Associates Morristown NJ USA

Experimental measurements made in this study on human and porcine eyes suggest that the resonant frequency for both cornea and sclera varies from 130 to 150 hz and increases slightly with increasing intraocular pressure. The values of the moduli calculated using the experimental values of the thickness are close to 2 MPa. Similar values of the modulus for cornea and sclera suggest that there is very little stress concentration at the cornea-scleral junction and that any stress concentration that occurs probably resides at the scleral attachment laterally and posteriorly. These moduli are close to those measured in vivo on human skin suggesting that the mechanism of tensile deformation of skin, cornea and sclera are similar. Our results suggest that the modulus of cornea and sclera can be measured non-invasively and non-destructively using vibrational OCT. Results of these studies will assist clinicians to better understand the influence of biomechanics on the outcome of corneal refractive surgery as well as the pathogenesis of eye disorders such as glaucoma, myopia and keratoconus.

关键词： Collagen Cornea Sclera Skin Biomechanics Vibrational OCT Optical Coherence Tomography (OCT) Modulus Resonant Frequency Mechanical Properties Myopia Keratoconus Glaucoma

Foraging ecology and occurrence of 7 sympatric babbler species （Timaliidae） in the lowland rainforest of Borneo and peninsular Malaysia

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Current Zoology 2016年第4期62卷 345-355页

作者： Alison R. STYRING Roslina RAGAI Mohamed ZAKARIA frederick h. ShELDON The Evergreen State College Olympia Washington 98505 USA Grand Perfect Sdn. Bhd. ParkCity Commerce Square 97000 Bintulu Sarawak Malaysia Department of Forest Management Faculty of Forestry Universiti Putra Malaysia Serdang Selangor Malaysia Museum of Natural Science and Department of Biological Sciences Louisiana State University Baton Rouge Louisiana USA 70803

Understanding foraging strategies of birds is essential to understanding mechanisms of their community assembly. To provide such information on a key Southeast Asian rainforest family, the babblers （Timaliidae）, we evaluated foraging behavior and abundance in 7 morphologically and behaviorally similar sympatric species （Cyanoderma erythropterum, C. rufifrons, Stachyris maculata, S. nigricollis, S. poliocephala, Macronus ptilosus, and Mixornis gularis） in 5 habitats defined by structural complexity：（1） continuous native rainforest, （2） logged native rainforest fragments, （3） mature industrial tree plantation, （4） young industrial plantation, and （5） oil palm plantation. Enough data were obtained to compare abundance in all 7 species and foraging behavior in 5. All species were common in forest fragments and mature industrial tree plantations and less so in continuous rainforest and young industrial plantations; only M. gularis occurred in oil palm. In terms of foraging, M. gularis was the greatest generalist; C. rufifrons foraged mainly on live leaves in the forest midstory; and S. maculata, C. eryth- ropterum, and M. ptilosus foraged mainly on dead leaves suspended in understory vegetation at sig- nificantly different heights. The dead-leaf substrate depends on a rich supply of falling leaves and ex- tensive understory structure, conditions most common in native forest and old industrial plantations, and less so in mature forest, young plantations, and oil palm. Because of the importance of foraging data to understanding and managing biodiversity, we encourage the development of foraging fields in eBird （***）, so that birdwatchers may help collect these relatively rare data.

关键词： Brunei dead leaves logged forest plantation Sabah Sarawak.

Virtual Biopsy and Physical Characterization of Tissues, Biofilms, Implants and Viscoelastic Liquids Using Vibrational Optical Coherence Tomography

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World Journal of Mechanics 2019年第1期9卷 1-16页

作者： frederick h. silver Ruchit G. Shah Dominick Benedetto Abhinav Dulur Thomas Kirn Department of Pathology and Laboratory Medicine Robert Wood Johnson Medical School Rutgers The State University of New Jersey Piscataway NJ USA Graduate Program in Biomedical Engineering Rutgers The State University of New Jersey Piscataway NJ USA Center for Advanced Eye Care Vero Beach FL USA

Tissue biopsies and implant analysis during animal testing or clinical studies are a requirement for development of new surgical materials and procedures. In this paper we report the use of vibrational OCT (VOCT) to evaluate the viscoelastic behavior of tissues, polymeric materials, biofilms, and viscoelastic solutions of macromolecules. Our results suggest that VOCT is a useful technique to characterize the behavior of cellular tissues and biofilms, polymeric implant materials and viscoelastic solutions used in medicine. It is demonstrated that the modulus and resonant frequency squared per unit thickness is a feature that can be used to characterize a variety of tissues. Further work is needed to understand the generalized behavior of synthetic polymers and viscoelastic solutions.

关键词： Optical Coherence Tomography Vibrational Optical Coherence Tomography Biofilm Viscoelastic Solutions Mechanical Properties Modulus Stiffness Tissues hyaluronic Acid

An anisotropic constitutive model of geomaterials based on true triaxial testing and its application

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Journal of Central South University 2017年第6期24卷 1430-1442页

作者： ZhANG Kun-yong frederick Nai Charkley Key Laboratory of Ministry of Education for Geomechanics and Embankment Engineering Nanjing 210098China Geotechnical Research Institute Hohai UniversityNanjing 210098China

Series of testing on coarse grained soils were carried out with a true triaxial testing apparatus. The loads were applied from the major principal and minor principal directions, respectively, to simulate the construction and water impounding process of a rock fill dam. The stress and strain relationships induced by the different loading methods were investigated. A remarkable stress-induced anisotropy under complex stress state was observed. Contrary to popular assumptions in traditional numerical analysis and constitutive models, it was found that different elastic modulus and Poisson ratio exist in different principal directions in rock fill dams. From the testing results, an anisotropic constitutive model based on Duncan-Chang nonlinear model is presented to overcome the limitations of axi-symmetric assumptions in conventional triaxial experiments and constitutive models. Both models were then applied in FEM analysis of an under-construction earth core high rock soil filled dam with the focus on hydraulic fracturing. The study reveals the major biases that exist when numerical analysis and constitutive models do not give serious consideration to the intermediate principal stress and anisotropy effects in soil rock built structures.

关键词： true triaxial test stress induced anisotropy constitutive model complex stress state finite element method (FEM)