Premise:The com bined effects of modern healthcare practices which prolong lifespan and declining birthrates have created unprecedented changes in age demographics worldwide that are especially pronounced in Japan,Sou...Premise:The com bined effects of modern healthcare practices which prolong lifespan and declining birthrates have created unprecedented changes in age demographics worldwide that are especially pronounced in Japan,South Korea,Europe,and North America.Since old age is the most significant predictor of dementia,global healthcare systems must rise to the challenge of providing care for those with neurodegenerative disorders.展开更多
This research identified difficulties faced by dairy farmers in family farming, describing this diagnosis through ergonomic demand items （EDIs）. The objective was to elaborate an organization model of work related t...This research identified difficulties faced by dairy farmers in family farming, describing this diagnosis through ergonomic demand items （EDIs）. The objective was to elaborate an organization model of work related to dairy farming （WRDF）. As a methodology, a descriptive exploratory study was carried out in 14 family dairy farms that were visited and had their activities monitored. As main results, 11 EDIs were identified. The ones grouped in the infrastructure factor showed the highest resolution priority. The WRDF model was composed of three categories： management, public policies management and infrastructure, which were further subdivided into technical and social aspects. From this perspective, it is believed that the implementation of the model can bring organizational improvement, once adjustments are made in the procedures and working conditions. This study sheds light on the conditions that need to be resolved with higher priority so that the farmers will remain in the dairy business.展开更多
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 musculosk...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.展开更多
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 pressu...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.展开更多
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 e...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.展开更多
Hylauronic acid (HA) is used as a viscoelastic in Ophthalmology during cataract surgery based on its high viscosity at rest, its ability to shear thin and dissipate energy during phacoemulsification. However, these pr...Hylauronic acid (HA) is used as a viscoelastic in Ophthalmology during cataract surgery based on its high viscosity at rest, its ability to shear thin and dissipate energy during phacoemulsification. However, these properties of HA solutions would make them susceptible to migration when used as dermal filler materials. In this study, we apply a new technique termed vibrational optical coherence tomography (VOCT) to compare the physical properties of different HA solutions and fillers used in facial aesthetics. Results presented in this study suggest that HA solutions and HA dermal fillers have markedly different physical properties. HA solutions are highly viscoelastic with high % viscous losses while fillers tend to have lower viscous energy dissipation properties. Clinical observations suggest that the high loss fillers are injected more superficially in the face where tension and internal and external forces are more likely minimized giving tissue of the hands and lips more volume and allowing more natural movement. In contrast, the lower loss gels that are used to lift tissue, generally have a higher G’, and are injected deeper into the face where injection and internal forces are likely to be higher. It is concluded that HA filler gel design can be optimized by use of VOCT to evaluate the % viscous energy loss both in vitro and in vivo.展开更多
Electrophysical devices based on diathermy are one of the modalities used by many professionals to treat pain. The objective of this study was to identify the effects of Tecartherapy on healthy and unhealthy tissues. ...Electrophysical devices based on diathermy are one of the modalities used by many professionals to treat pain. The objective of this study was to identify the effects of Tecartherapy on healthy and unhealthy tissues. A systematic review of Tecartherapy technology was carried out. Articles published up to the year 2023 were investigated. The search argument used was “Capacitive-resistive electrical transfer” OR “Tecar” OR “Therapy Tecar” OR “CRET” in the BVS, Cochrane, PEDro, PubMed, IEEE Explore databases, Scielo and Web of Science. As for the main results of using Tecartherapy, there is an increase in temperature. In healthy tissues there is an increase in local blood flow, a decrease in muscle fatigue and an increase in muscle flexibility. In addition to the effects observed on healthy tissues, pain reduction and improved joint function were also observed. It was concluded that this technology has similar effects to other diathermy, but Tecartherapy proved to be safer and more comfortable. .展开更多
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 ...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.展开更多
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. G...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.展开更多
Electrospinning is one of the most effective approaches to fabricate tissue-engineered scaffolds composed of nano-to sub-microscale fibers that simulate a native extracellular matrix.However,one major concern about el...Electrospinning is one of the most effective approaches to fabricate tissue-engineered scaffolds composed of nano-to sub-microscale fibers that simulate a native extracellular matrix.However,one major concern about electrospun scaffolds for tissue repair and regeneration is that their small pores defined by densely compacted fibers markedly hinder cell infiltration and tissue ingrowth.To address this problem,researchers have developed and investigated various methods of manipulating scaffold structures to increase pore size or loosen the scaffold.These methods involve the use of physical treatments,such as salt leaching,gas foaming and custom-made collectors,and combined techniques to obtain electrospun scaffolds with loose fibrous structures and large pores.This article provides a summary of these motivating electrospinning techniques to enhance cell infiltration of electrospun scaffolds,which may inspire new electrospinning techniques and their new biomedical applications.展开更多
The phenomenon of particle interaction involved in pulmonary drug delivery belongs to a wide variety of disciplines of particle technology, in particular, fluidization. This paper reviews the basic concepts of pulmona...The phenomenon of particle interaction involved in pulmonary drug delivery belongs to a wide variety of disciplines of particle technology, in particular, fluidization. This paper reviews the basic concepts of pulmonary drug delivery with references to fluidization research, in particular, studies on Geldart group C powders. Dry powder inhaler device-formulation combination has been shown to be an effective method for delivering drugs to the lung for treatment of asthma, chronic obstructive pulmonary disease and cystic fibrosis. Even with advanced designs, however, delivery efficiency is still poor mainly due to powder dispersion problems which cause poor lung deposition and high dose variability. Drug particles used in current inhalers must be 1–5 μm in diameter for effective deposition in small-diameter airways and alveoli. These powders are very cohesive, have poor flowability, and are difficult to disperse into aerosol due to cohesion arising from van der Waals attraction. These problems are well known in fluidization research, much of which is highly relevant to pulmonary drug delivery.展开更多
基金funded by the Natural Sciences and Engineering Research Council of Canada(RGPIN:2016-05964&2023-04283 to JHK)the University of Manitoba Tri-Agency Bridge Funding(#57289 to JHK)the Ricard Foundation’s Baxter Bursary(to JP)。
文摘Premise:The com bined effects of modern healthcare practices which prolong lifespan and declining birthrates have created unprecedented changes in age demographics worldwide that are especially pronounced in Japan,South Korea,Europe,and North America.Since old age is the most significant predictor of dementia,global healthcare systems must rise to the challenge of providing care for those with neurodegenerative disorders.
文摘This research identified difficulties faced by dairy farmers in family farming, describing this diagnosis through ergonomic demand items （EDIs）. The objective was to elaborate an organization model of work related to dairy farming （WRDF）. As a methodology, a descriptive exploratory study was carried out in 14 family dairy farms that were visited and had their activities monitored. As main results, 11 EDIs were identified. The ones grouped in the infrastructure factor showed the highest resolution priority. The WRDF model was composed of three categories： management, public policies management and infrastructure, which were further subdivided into technical and social aspects. From this perspective, it is believed that the implementation of the model can bring organizational improvement, once adjustments are made in the procedures and working conditions. This study sheds light on the conditions that need to be resolved with higher priority so that the farmers will remain in the dairy business.
文摘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.
文摘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.
文摘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.
文摘Hylauronic acid (HA) is used as a viscoelastic in Ophthalmology during cataract surgery based on its high viscosity at rest, its ability to shear thin and dissipate energy during phacoemulsification. However, these properties of HA solutions would make them susceptible to migration when used as dermal filler materials. In this study, we apply a new technique termed vibrational optical coherence tomography (VOCT) to compare the physical properties of different HA solutions and fillers used in facial aesthetics. Results presented in this study suggest that HA solutions and HA dermal fillers have markedly different physical properties. HA solutions are highly viscoelastic with high % viscous losses while fillers tend to have lower viscous energy dissipation properties. Clinical observations suggest that the high loss fillers are injected more superficially in the face where tension and internal and external forces are more likely minimized giving tissue of the hands and lips more volume and allowing more natural movement. In contrast, the lower loss gels that are used to lift tissue, generally have a higher G’, and are injected deeper into the face where injection and internal forces are likely to be higher. It is concluded that HA filler gel design can be optimized by use of VOCT to evaluate the % viscous energy loss both in vitro and in vivo.
文摘Electrophysical devices based on diathermy are one of the modalities used by many professionals to treat pain. The objective of this study was to identify the effects of Tecartherapy on healthy and unhealthy tissues. A systematic review of Tecartherapy technology was carried out. Articles published up to the year 2023 were investigated. The search argument used was “Capacitive-resistive electrical transfer” OR “Tecar” OR “Therapy Tecar” OR “CRET” in the BVS, Cochrane, PEDro, PubMed, IEEE Explore databases, Scielo and Web of Science. As for the main results of using Tecartherapy, there is an increase in temperature. In healthy tissues there is an increase in local blood flow, a decrease in muscle fatigue and an increase in muscle flexibility. In addition to the effects observed on healthy tissues, pain reduction and improved joint function were also observed. It was concluded that this technology has similar effects to other diathermy, but Tecartherapy proved to be safer and more comfortable. .
文摘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.
文摘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.
基金We greatly thank financial supports from the American Heart Association(Beginning Grant-in-Aid,#14BGIA20510066)the National Scientific Foundation(CAREER,#1554835)in the United States of America.
文摘Electrospinning is one of the most effective approaches to fabricate tissue-engineered scaffolds composed of nano-to sub-microscale fibers that simulate a native extracellular matrix.However,one major concern about electrospun scaffolds for tissue repair and regeneration is that their small pores defined by densely compacted fibers markedly hinder cell infiltration and tissue ingrowth.To address this problem,researchers have developed and investigated various methods of manipulating scaffold structures to increase pore size or loosen the scaffold.These methods involve the use of physical treatments,such as salt leaching,gas foaming and custom-made collectors,and combined techniques to obtain electrospun scaffolds with loose fibrous structures and large pores.This article provides a summary of these motivating electrospinning techniques to enhance cell infiltration of electrospun scaffolds,which may inspire new electrospinning techniques and their new biomedical applications.
文摘The phenomenon of particle interaction involved in pulmonary drug delivery belongs to a wide variety of disciplines of particle technology, in particular, fluidization. This paper reviews the basic concepts of pulmonary drug delivery with references to fluidization research, in particular, studies on Geldart group C powders. Dry powder inhaler device-formulation combination has been shown to be an effective method for delivering drugs to the lung for treatment of asthma, chronic obstructive pulmonary disease and cystic fibrosis. Even with advanced designs, however, delivery efficiency is still poor mainly due to powder dispersion problems which cause poor lung deposition and high dose variability. Drug particles used in current inhalers must be 1–5 μm in diameter for effective deposition in small-diameter airways and alveoli. These powders are very cohesive, have poor flowability, and are difficult to disperse into aerosol due to cohesion arising from van der Waals attraction. These problems are well known in fluidization research, much of which is highly relevant to pulmonary drug delivery.
