Academic literature on the topic 'Nerve mechanical analysis'
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Journal articles on the topic "Nerve mechanical analysis"
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Baer, Gerhard Alfred, and Ralph Beitzel. "Spinal cord injury: the cost of mechanical ventilation versus phrenic nerve stimulation." British Journal of Neuroscience Nursing 18, no. 3 (June 2, 2022): 134–36. http://dx.doi.org/10.12968/bjnn.2022.18.3.134.
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Patients with respiratory insufficiency caused by tetraplegia at or above the level of cervical segment two can be treated with phrenic nerve stimulation instead of mechanical ventilation. An analysis of the annual invoices for single use airway equipment of 20 patients using phrenic nerve stimulation and 20 patients who were mechanically ventilated was conducted. The initial implantation of the phrenic nerve stimulation device costs considerably more than the mechanical ventilation device. However, this analysis found that the cost of running a phrenic nerve stimulator device is lower because of the reduced amount of airway nursing equipment needed. This analysis demonstrates that the cost of implanting a phrenic nerve stimulator device would be repaid within 4 years.
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Lennertz, Richard C., Karen A. Medler, James L. Bain, Douglas E. Wright, and Cheryl L. Stucky. "Impaired sensory nerve function and axon morphology in mice with diabetic neuropathy." Journal of Neurophysiology 106, no. 2 (August 2011): 905–14. http://dx.doi.org/10.1152/jn.01123.2010.
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Diabetes is the most prevalent metabolic disorder in the United States, and between 50% and 70% of diabetic patients suffer from diabetes-induced neuropathy. Yet our current knowledge of the functional changes in sensory nerves and their distal terminals caused by diabetes is limited. Here, we set out to investigate the functional and morphological consequences of diabetes on specific subtypes of cutaneous sensory nerves in mice. Diabetes was induced in C57Bl/6 mice by a single intraperitoneal injection of streptozotocin. After 6–8 wk, mice were characterized for behavioral sensitivity to mechanical and heat stimuli followed by analysis of sensory function using teased nerve fiber recordings and histological assessment of nerve fiber morphology. Diabetes produced severe functional impairment of C-fibers and rapidly adapting Aβ-fibers, leading to behavioral hyposensitivity to both mechanical and heat stimuli. Electron microscopy images showed that diabetic nerves have axoplasm with more concentrated organelles and frequent axon-myelin separations compared with control nerves. These changes were restricted to the distal nerve segments nearing their innervation territory. Furthermore, the relative proportion of Aβ-fibers was reduced in diabetic skin-nerve preparations compared with nondiabetic control mice. These data identify significant deficits in sensory nerve terminal function that are associated with distal fiber loss, morphological damage, and behavioral hyposensitivity in diabetic C57Bl/6 mice. These findings suggest that diabetes damages sensory nerves, leading to functional deficits in sensory signaling that underlie the loss of tactile acuity and pain sensation associated with insensate diabetic neuropathy.
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Loizides, A., S. Peer, M. Plaikner, T. Djurdjevic, and H. Gruber. "Punched Nerve Syndrome: Ultrasonographic Appearance of Functional Vascular Nerve Impairment." Ultraschall in der Medizin - European Journal of Ultrasound 33, no. 04 (December 9, 2011): 352–56. http://dx.doi.org/10.1055/s-0031-1281831.
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Abstract Purpose: The mechanical impact of a neighboring vessel on a “punched” nerve segment is thought to be one possible cause of compression neuropathy but has not been proven definitively. We report on 9 subjects with unclear clinical mononeuropathies in whom we could clearly define peripheral nerve impairment by such vessels on real-time high-resolution ultrasound (HRUS). Materials and Methods: Nine subjects with unclear mononeuropathy based on clinical neurological examination were referred to our department for HRUS assessment. The shape, inner and outer echotexture, size and diameter, and overall integrity of these nerves were assessed including an exact analysis of the surrounding soft tissues to search for potentially extraneural pathology. This included duplex imaging to identify even tiny atypical vascular structures. Results: In all patients duplex HRUS showed the pulsatile and “punching” character of the relevant vessels and the direct mechanical impact of these vessel. The involved nerve segments appeared enlarged with a hypoechoic change of echotexture including at least partial masking of their inner fascicular texture. Conclusion: Although rare, a “punching” vessel can be the cause of a compression neuropathy. Therefore, duplex HRUS must be included in every HRUS examination of patients with otherwise unclear mononeuropathy.
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Akouissi, Outman, Stéphanie P. Lacour, Silvestro Micera, and Antonio DeSimone. "A finite element model of the mechanical interactions between peripheral nerves and intrafascicular implants." Journal of Neural Engineering 19, no. 4 (July 21, 2022): 046017. http://dx.doi.org/10.1088/1741-2552/ac7d0e.
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Abstract Objective. Intrafascicular peripheral nerve implants are key components in the development of bidirectional neuroprostheses such as touch-enabled bionic limbs for amputees. However, the durability of such interfaces is hindered by the immune response following the implantation. Among the causes linked to such reaction, the mechanical mismatch between host nerve and implant is thought to play a decisive role, especially in chronic settings. Approach. Here we focus on modeling mechanical stresses induced on the peripheral nerve by the implant’s micromotion using finite element analysis. Through multiple parametric sweeps, we analyze the role of the implant’s material, geometry (aspect-ratio and shape), and surface coating, deriving a set of parameters for the design of better-integrated implants. Main results. Our results indicate that peripheral nerve implants should be designed and manufactured with smooth edges, using materials at most three orders of magnitude stiffer than the nerve, and with innovative geometries to redistribute micromotion-associated loads to less delicate parts of the nerve such as the epineurium. Significance. Overall, our model is a useful tool for the peripheral nerve implant designer that is mindful of the importance of implant mechanics for long term applications.
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Michaelis, M., K. H. Blenk, W. Janig, and C. Vogel. "Development of spontaneous activity and mechanosensitivity in axotomized afferent nerve fibers during the first hours after nerve transection in rats." Journal of Neurophysiology 74, no. 3 (September 1, 1995): 1020–27. http://dx.doi.org/10.1152/jn.1995.74.3.1020.
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1. Spontaneous activity and ectopic mechanical excitability of axotomized unmyelinated and myelinated fibers in the sural nerve were examined in anesthetized rats. The analysis was performed within 30 h after the nerve lesion using single-fiber recordings that were performed proximal to the severed nerve end. 2. Among all unmyelinated fibers tested (n = 865), 4-8% exhibited persistent spontaneous activity of low and irregular frequency. The percentage of spontaneously active C fibers did not change significantly during the first 30 h. Only 6 of 796 A fibers had spontaneous activity. 3. Mechanical stimulation of the cut nerve end excited 5-8% of all C fibers under investigation. No development with time could be detected in the frequency of mechanically excitable C fibers. In contrast, beginning 6 h after nerve transection, the number of mechanically excitable A fibers rose with time, reaching 27% after 22-30 h. 4. Among the A fibers (C fibers) that exhibited mechanical excitability or spontaneous activity, only 4% (25%) had both properties, whereas 96% (75%) were either mechanosensitive or spontaneously active. 5. With time after the nerve lesion, the mean discharge rate of all spontaneously discharging C fibers decreased significantly from 49 imp/min (0.5-9 h after nerve lesion) to 11 imp/min after 22-30 h. The mean discharge rate of C fibers exhibiting solely spontaneous activity and those C fibers that were additionally mechanosensitive did not differ significantly.(ABSTRACT TRUNCATED AT 250 WORDS)
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Garg, Rohit, Safak Uygur, Joanna Cwykiel, and Maria Siemionow. "Development of Targeted Muscle Reinnervation Model in Hind Limb Amputated Rats." Journal of Reconstructive Microsurgery 34, no. 07 (April 1, 2018): 509–13. http://dx.doi.org/10.1055/s-0038-1639602.
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Background Targeted muscle reinnervation (TMR) is a novel approach to postamputation neuroma pain; however, this has not been explicitly studied. The purpose of this study was to develop a TMR model in hind limb amputated rats. Methods Ten hind limbs from 5 Sprague Dawley cadaver rats were used. Sciatic nerve, main branches of the sciatic nerve (common peroneal, tibial, sural), motor branches from the sciatic nerve to the biceps femoris and cauda femoris, gluteal nerve and its motor branches to the semimembranosus, and biceps femoris and femoral nerve were dissected to look for consistent nerve anatomy that can be used for TMR in the rat hind limb amputation model. Transfemoral amputation was performed and two types of coaptations were made: common peroneal nerve to motor branch to biceps femoris and tibial nerve to motor branch to semimembranosus. Results The total surgical time for the dissection, amputation, and coaptation of nerves was ∼90 minutes. A total of 100 nerves were dissected in 10 rat hind limbs. Anatomical dissections were straightforward to perform. Anatomy of the dissected nerves was consistent. Hind limb amputations were performed without damaging the target muscles and nerves. Nerve lengths were sufficient for coaptation without any tension. Conclusions To the best of our knowledge, this is the first report on TMR model in hind limb amputated rats. This model will allow for mechanical, electromyography (EMG), and histological analysis for future assessment of neuroma prevention.
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Sekiya, Tetsuji, Masahiro Matsumoto, Ken Kojima, Kazuya Ono, Yayoi S. Kikkawa, Shinpei Kada, Hideaki Ogita, et al. "Mechanical stress-induced reactive gliosis in the auditory nerve and cochlear nucleus." Journal of Neurosurgery 114, no. 2 (February 2011): 414–25. http://dx.doi.org/10.3171/2010.2.jns091817.
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Object Hearing levels following microsurgical treatment gradually deteriorate in a number of patients treated for vestibular schwannoma (VS), especially in the subacute postoperative stage. The cause of this late-onset deterioration of hearing is not completely understood. The aim of this study was to investigate the possibility that reactive gliosis is a contributory factor. Methods Mechanical damage to nerve tissue is a feature of complex surgical procedures. To explore this aspect of VS treatment, the authors compressed rat auditory nerves with 2 different degrees of injury while monitoring the compound action potentials of the auditory nerve and the auditory brainstem responses. In this experimental model, the axons of the auditory nerve were quantitatively and highly selectively damaged in the cerebellopontine angle without permanent compromise of the blood supply to the cochlea. The temporal bones were processed for immunohistochemical analysis at 1 week and at 8 weeks after compression. Results Reactive gliosis was induced not only in the auditory nerve but also in the cochlear nucleus following mechanical trauma in which the general shape of the auditory brainstem response was maintained. There was a substantial outgrowth of astrocytic processes from the transitional zone into the peripheral portion of the auditory nerve, leading to an invasion of dense gliotic tissue in the auditory nerve. The elongated astrocytic processes ran in parallel with the residual auditory neurons and entered much further into the cochlea. Confocal images disclosed fragments of neurons scattered in the gliotic tissue. In the cochlear nucleus, hypertrophic astrocytic processes were abundant around the soma of the neurons. The transverse diameter of the auditory nerve at and proximal to the compression site was considerably reduced, indicating atrophy, especially in rats in which the auditory nerve was profoundly compressed. Conclusions The authors found for the first time that mechanical stress to the auditory nerve causes substantial reactive gliosis in both the peripheral and central auditory pathways within 1–8 weeks. Progressive reactive gliosis following surgical stress may cause dysfunction in the auditory pathways and may be a primary cause of progressive hearing loss following microsurgical treatment for VS.
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DAI, PEISHAN, HAN HAN, YALI ZHAO, and MIN FAN. "FINITE ELEMENT ANALYSIS OF THE MECHANICAL CHARACTERISTICS OF GLAUCOMA." Journal of Mechanics in Medicine and Biology 16, no. 04 (June 2016): 1650060. http://dx.doi.org/10.1142/s0219519416500603.
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Purpose: Construct a finite element model of the human eye to quantitatively analyze the mechanical characteristics of the human eye, especially the glaucoma damage process of the optic nerve head (ONH). Method: First, the geometry model of the human eye with nonuniform thickness was established based on a reasonable hypothesis and assumptions. Because the ONH is an important factor for glaucoma, we refine the structure of the ONH with lamina cribrosa. Then, mesh division was applied for finite element analysis. To simplify the complexity of the analysis, the materials of the model were assumed to be isotropic linear elastic materials, and physical properties such as Young’s modulus and Poisson’s ratio were set according to published literature. Next, proper constraints and loads were applied to the model and solved with a finite element method. Result: A finite element model of the human eye was created to simulate the mechanical characteristics of the eye structures under high intraocular pressure (IOP). The ONH depressed 1.057[Formula: see text]mm under 0.009[Formula: see text]MPa pressure to simulate high IOP. Conclusion: The constructed model is able to quantitatively simulate excavation of the optic disc and damage of the optic nerve. The result proved Houcheng Liang’s hypothesis about the ONH damage mechanism in glaucoma.
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Winkelstein, Beth A., and Joyce A. DeLeo. "Mechanical Thresholds for Initiation and Persistence of Pain Following Nerve Root Injury: Mechanical and Chemical Contributions at Injury." Journal of Biomechanical Engineering 126, no. 2 (April 1, 2004): 258–63. http://dx.doi.org/10.1115/1.1695571.
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There is much evidence supporting the hypothesis that magnitude of nerve root mechanical injury affects the nature of the physiological responses which can contribute to pain in lumbar radiculopathy. Specifically, injury magnitude has been shown to modulate behavioral hypersensitivity responses in animal models of radiculopathy. However, no study has determined the mechanical deformation thresholds for initiation and maintenance of the behavioral sensitivity in these models. Therefore, it was the purpose of this study to quantify the effects of mechanical and chemical contributions at injury on behavioral outcomes and to determine mechanical thresholds for pain onset and persistence. Male Holtzman rats received either a silk or chromic gut ligation of the L5 nerve roots, a sham exposure of the nerve roots, or a chromic exposure in which no mechanical deformation was applied but chromic gut material was placed on the roots. Using image analysis, nerve root radial strains were estimated at the time of injury. Behavioral hypersensitivity was assessed by measuring mechanical allodynia continuously throughout the study. Chromic gut ligations produced allodynia responses for nerve root strains at two-thirds of the magnitudes of those strains which produced the corresponding behaviors for silk ligation. Thresholds for nerve root compression producing the onset (8.4%) and persistence of pain (17.4%–22.2%) were determined for silk ligation in this lumbar radiculopathy model. Such mechanical thresholds for behavioral sensitivity in a painful radiculopathy model begin to provide biomechanical data which may have utility in broader experimental and computational models for relating injury biomechanics and physiologic responses of pain.
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Hsiang, Shih-Wei, Chin-Chuan Tsai, Fuu-Jen Tsai, Tin-Yun Ho, Chun-Hsu Yao, and Yueh-Sheng Chen. "Novel use of biodegradable casein conduits for guided peripheral nerve regeneration." Journal of The Royal Society Interface 8, no. 64 (April 27, 2011): 1622–34. http://dx.doi.org/10.1098/rsif.2011.0009.
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Recent advances in nerve repair technology have focused on finding more biocompatible, non-toxic materials to imitate natural peripheral nerve components. In this study, casein protein cross-linked with naturally occurring genipin (genipin-cross-linked casein (GCC)) was used for the first time to make a biodegradable conduit for peripheral nerve repair. The GCC conduit was dark blue in appearance with a concentric and round lumen. Water uptake, contact angle and mechanical tests indicated that the conduit had a high stability in water and did not collapse and cramped with a sufficiently high level of mechanical properties. Cytotoxic testing and terminal deoxynucleotidyl transferase dUTP nick-end labelling assay showed that the GCC was non-toxic and non-apoptotic, which could maintain the survival and outgrowth of Schwann cells. Non-invasive real-time nuclear factor-κB bioluminescence imaging accompanied by histochemical assessment showed that the GCC was highly biocompatible after subcutaneous implantation in transgenic mice. Effectiveness of the GCC conduit as a guidance channel was examined as it was used to repair a 10 mm gap in the rat sciatic nerve. Electrophysiology, labelling of calcitonin gene-related peptide in the lumbar spinal cord, and histology analysis all showed a rapid morphological and functional recovery for the disrupted nerves. Therefore, we conclude that the GCC can offer great nerve regeneration characteristics and can be a promising material for the successful repair of peripheral nerve defects.
Dissertations / Theses on the topic "Nerve mechanical analysis"
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Wong, Matthew Q. "Transcriptional analysis of the healing response of wounded nerves treated with collagen and silicone tubes." Thesis, Massachusetts Institute of Technology, 2008. http://hdl.handle.net/1721.1/44881.
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Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2008.Includes bibliographical references (leaves 49-53).
This study examines the transcriptional differences between nerve wounds treated with silicone tubes and those treated with collagen nerve regeneration templates. The primary motivation for the study is to test the hypothesis that the discrepancy between the low-quality regenerate that forms in a silicone tube and the high-quality regenerate that forms in a collagen tube is due to differences in gene transcription. We used in vivo experiments on rat sciatic nerves with the use of real-time PCR to study the mRNA expression levels of certain inflammatory cytokines and contractile proteins after injury in both silicone-treated and collagen-treated nerve wounds. The contents of the wound site were analyzed on days 1, 3, 7, 14, and 21 following injury. The results of this experiment showed that although a difference in mRNA expression of [alpha]-SM actin is significantly higher at later time points in silicone-treated wounded nerves as compared to collagen-treated wounded nerves, there is little or no significant difference in the mRNA expression of TGF-[beta]1, TGF-[beta]2, and TGF-[beta]3 in wounds from the two devices. This suggests that the presence of a collagen regeneration nerve template does not direct the wound healing process at a transcriptional level.
by Matthew Quin-men Wong.
S.M.
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Cox, Thomas-Glyn Hunter. "Propagation of mechanical strain in peripheral nerve trunks and their interaction with epineural structures." Thesis, 2017. https://doi.org/10.7912/C2GD32.
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Indiana University-Purdue University Indianapolis (IUPUI)Advances in peripheral nerve electrode technology have outpaced the advances in chronic implantation reliability of the electrodes. An observable trend is the increased deposition of fibrotic encapsulation tissue around the electrode to shift its position away from the implantation site and subsequently reducing performance. A finite element model (FEM) is developed in conjunction with tensile testing and digital image correlation of strain to understand the relationship between cuff electrode attachment and the strain environment of the nerve. A laminar and bulk nerve model are both developed with material properties found in literature and geometry found from performing histology. The introduction of a cuff electrode to an axially stretched nerve indicates a significant behavior deviation from the expected response of the axial strain environment. When implemented in ex-vivo tensile testing, results indicate that the reduction of strain is statistically significant but becomes much more apparent when paired with a digital image correlation system to compare predicted and measured effects. A robust FEM is developed and tested to emphasize the effect that the boundary conditions and attachment methodology significantly effects the strain environment. By coupling digital image correlation with FEM, predictive models can be made to the strain environment to better design around the long term chronic health of the implant.
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Wei-ChinHuang and 黃偉欽. "Nano-mechanical analyses of myelination process and topographical design of guiding channels for nerve conduit." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/35553457518252878697.
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博士國立成功大學
材料科學及工程學系碩博士班
101
In vitro development of myelinated axons were differentiated by Schwann cells co-cultured with PC12 cells. In first part of this thesis, the three major myelination stages with distinct structural characteristics, mechanical properties and thicknesses around the myelinated axon with various co-culture times were confirmed. The dynamic contact module and continuous depth sensing nano-indentation are used on the myelinated structure to obtain the load-on-sample versus measured displacement curve of a multi-layered myelin sheath, which is used to determine the work required for the nano-indentation tip to penetrate the myelin sheath structure. By analyzing the harmonic contact stiffness versus the measured displacement profile, the results can be used to estimate the three stages of the multi-layered structure on a myelinated axon. In the next part of this thesis, different sizes of morphologically and chemically modified microgrooves were fabricated to evaluate the Schwann cells adhesion and cell alignment on the surface. By all the results of these observations, Schwann cells performed different adhesion properties with different microgrooves designs. Eventually, plano-concave fibers (PCFs) of poly-lactic acid combined advantages of these sizes of microgrooves are designed as a unit of guided channels in nerve conduit. The guided channels designed for supporting Schwann cells to facilitate mass transport and promote nerve regeneration. The surface-modified PCFs are imprinted with linearly patterned grooves (LPGs) to guide adherent Schwann cell elongation and axon extension. After being co-cultured with PC12 neuron-like cells, Schwann cells differentiate into the myelinated type and interact with PC12 axons. The myelinated axons aggregate as a linear bundle and extend along the direction of LPGs on a PCF. The design of PCFs can potentially bridge gaps in injured nerves, improving the therapeutic efficacy of nerve regeneration.
Conference papers on the topic "Nerve mechanical analysis"
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Nakagawa, K., T. Takaki, Y. Morita, and E. Nakamachi. "2D Phase-Field Analyses of Axonal Extension of Nerve Cell." In ASME 2013 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/imece2013-64281.
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In this study, we aimed to develop a computer-aided simulation technique to predict the axonal extension in the neuronal network evolution processes for design new scaffolds to activate the nerve cell and promote the nerve regeneration. We developed a mathematical model of axonal extension by using phase-field method and evaluated the validity of the mathematical model by comparison with the experiments. In the previous experimental studies, the peripheral nerve scaffold has been introduced to guide the axonal extension. Damaged part of nerve was replaced by the artificial tube as the scaffold to induce the axonal growth through the artificial tube and regenerate the nerve network. However, the scaffold made of biodegradable materials has a problem that it is degraded and absorbed before the nerve regenerate, and then the nerve cannot regenerate. Therefore, there is a need for the design and development of a scaffold for nerve regeneration to promote nerve regeneration. For that purpose, it is necessary to understand the difference between the axonal extensions by the surrounding environment, such as the shape or materials of the scaffold for nerve regeneration. In particular, the numerical technique to analyze the remodeling process of the nerve in the scaffold is strongly required to be established because the in-vivo experimental observation technology at the micro scale, bioethical issues in the animal experiment and requires time and money are also remained as unresolved problems. In this study, we developed a new simulation code which employed the phase-field method to predict the two-dimensional dendritic and axonal growth processes of nerve cells on cultivation scaffolds. We curried out the phase-field analyses to make clear how the parameters of Kobayashi–Warren–Carter (KWC) phase-field model affected on the morphologic growths of dendrite and axon. Simultaneously, we had observed the axonal extension process by using the PC-12D cells with nerve growth factor (NGF) on two-dimensional cultivation dish. Based on these axonal extension observation results, we approximated the morphological changes and establish the phenomenological model for phase-field analysis. Finally, we confirmed the validity of our newly developed phase-field simulation scheme in two dimensions by comparison with the experiments.
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Yazawa, Toru, Yukio Shimoda, Satoru Shimizu, and Tomoo Katsuyama. "Neurodynamical Control of the Heart of Freely Moving Animals Including Humans." In ASME 2012 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/imece2012-85872.
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Two kinds of nerves, acceleratory and inhibitory cardio-regulator nerves, innervate the heart. They are known to discharge concurrently to maintain an equilibrium state of the body. The nerves are also known to change their frequency of discharge in a reflexive manner to meet the demand from the periphery; such as augmentation of oxygen supply or vice versa. Consequently, the heart exhibits dynamic change in its pumping rate and force of contraction. If the control system fails, the heart exhibits unhealthy state. However, assessment of healthy/unhealthy status is uneasy because we are not able to monitor the nerve activities by non-invasive methods. Therefore, we challenged to detect state of the heart without nerve-recordings. We used the detrended fluctuation analysis (DFA) applying to heartbeat interval time series because DFA has been believed that it can quantify the state of heart. We performed DFA on the EKGs (electrocardiograms) from various living organisms including humans. The objective of this research was to determine whether the analytical technology, DFA, could function as a useful method for the evaluation of the subject’s quality of cardiovascular-related illness and transition to and from a normal healthy state. We found that DFA could describe brain-heart interaction quantitatively: the scaling exponents of (1) healthy, (2) sick-type (such as stressful or arrhythmic states), and (3) unpredictable-death type (such as ischemic heart disease) were corresponded to individuals who exhibited, (1) nearly one, (2) less than one, and (3) greater than one, respectively. We conclude that scaling exponents could determine whether the subjects are under sick or healthy conditions on the basis of cardiac physiology.
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Mahmoudi, Mehrak, Piroz Zamankhan, and William Polashenski. "Simulations of Synaptic Transmission Using Lattice Boltzmann Methods." In ASME 2002 International Mechanical Engineering Congress and Exposition. ASMEDC, 2002. http://dx.doi.org/10.1115/imece2002-32812.
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The nervous system remains one of the least understood biological structures due in large part to the enormous complexity of this organ. A theoretical model for the transfer of nerve impulses would be valuable for the analysis of various phenomena in the nervous system, which are difficult to study by experiments. The central nervous system is composed of more than 100 billion neurons, through which information is transmitted via nerve impulses. Nerve impulses are not immediately apparent since each impulse may be blocked during transmission, changed from a single impulse into repetitive impulse, or integrated with impulses from other neurons to form highly intricate patterns. In the human central nervous system, a neuron secretes a chemical substance called a neurotransmitter at the synapse, and this transmitter in turn acts on another neuron to cause excitation, inhibition, or some other modification of its sensitivity.
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Suzuki, Kei, Toshihiko Shiraishi, Shin Morishita, and Hiroshi Kanno. "Effects of Mechanical Vibration on Proliferation and Differentiation of Neural Stem Cells." In ASME 2008 International Mechanical Engineering Congress and Exposition. ASMEDC, 2008. http://dx.doi.org/10.1115/imece2008-66831.
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Neural stem cells have been studied to promote neurogenesis in regenerative therapy. The control of differentiation of neural stem cells to nerve cells and the increase of the number of nerve cells are needed. For the purpose of them, it is important to investigate not only chemical factors but also mechanical factors such as hydrostatic pressure in brain and mechanical vibration in walking. In this study, sinusoidal inertia force was applied to cultured neural stem cells and the effects of mechanical vibration on the cells were investigated. After the cells were cultured in culture plates for one day and adhered on the cultured plane, vibrating group of the culture plates was set on an aluminum plate attached to an exciter and cultured under sinusoidal excitation for 24 hours a day during 26 days. The amplitude of the acceleration on the culture plate was set to 0.25 G and the frequency was set to 25 Hz. The time evolution of cell density was obtained by counting the number of cells at every 3 or 4 days. The expression of Akt, phosphorylated Akt (p-Akt), MAPK, and phosphorylated MAPK (p-MAPK) was detected by western blotting analysis at 7 days of culture to understand the mechanism of cell proliferation. Akt and MAPK are part of signaling pathways in relation to cell proliferation. The phosphorylation of Akt suppresses apoptosis and the phosphorylation of MAPK activates cell division. The gene expression of MAP-2, NFH, GFAP, and nestin was detected by real-time RT-PCR analysis at 7 days of culture to obtain a ratio of differentiation of neural stem cells to nerve or glia cells. MAP-2 and NFH are nerve cell markers, GFAP is a glia cell marker, and nestin is a stem cell marker. The results obtained are as follows. The cell density of the vibrating group was three times higher than that of the non-vibrating group at 26 days of culture. p-Akt was enhanced by the mechanical vibration while p-MAPK was not. There is no significant difference of the gene expression level of MAP-2, NFH, GFAP, and nestin between the vibrating and non-vibrating groups. These results suggest that the mechanical vibration promotes the proliferation of neural stem cells and its cause is likely the suppression of apoptosis but not the activation of cell division, and that the mechanical vibration at the experimental condition does not affect the differentiation of neural stem cells to nerve or glia cells.
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Elangovan, Shreehari, and Gregory M. Odegard. "Finite Element Modeling of Intraneural Ganglion Cysts of the Common Peroneal Nerve." In ASME 2009 International Mechanical Engineering Congress and Exposition. ASMEDC, 2009. http://dx.doi.org/10.1115/imece2009-11637.
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Intraneural Ganglion Cysts [IGC] are a set of medical conditions that result in denervation of the muscles innervated by the cystic nerve leading to pain and loss of function. Current treatment approaches only temporarily alleviate pain and denervation which, however, does not prevent cyst recurrence. Hence, a mechanistic understanding of the pathogenesis of IGC can help clinicians understand them better and therefore device more effective treatment options. In this study, a preliminary analysis methodology is established to investigate the pathogenesis of IGC.
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Biswas, Amitava. "A Novel Analysis of the Mechanics of Cochlea, the Inner Ear." In ASME 2003 International Mechanical Engineering Congress and Exposition. ASMEDC, 2003. http://dx.doi.org/10.1115/imece2003-42394.
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The human ear is often regarded as a paragon of mechanical engineering. To understand how the hearing system works, scientists have proposed detailed models of its specific aspects—the transfer of acoustic energy from the atmosphere to the tympanic membrane via the external ear; the coupling of the tympanic membrane to the oval window of the cochlea via ossicles; the resultant fluidic oscillations in the cochlear ducts; the formation of traveling waves in the basilar membrane of the cochlea; the mechanical stimulation of inner hair cells by the basilar membrane; and the consequential transduction of nerve impulses. Scientists have also proposed models to explain the phenomenon of enhancement of the traveling waves in the basilar membrane by synchronized co-contraction in the length of outer hair cells (OHCs). Although it is unrealistic that any OHC would contract in length without expanding in diameter, the models proposed by other analysts have so far incorporated the longitudinal contraction of OHCs only, suggesting that the impact of any diametric expansion of OHCs would be relatively trival. Here we show that the basilar membrane would behave like a Beam-Column system, which may be significantly influenced by the diametric expansion of OHCs.
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Lahiff, Christina-Anne, Millicent Schlafly, and Kyle Reed. "Effects on Balance When Interfering With Proprioception at the Knee." In ASME 2017 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2017. http://dx.doi.org/10.1115/imece2017-71573.
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After experiencing a stroke, 80% of individuals face hemiparesis causing muscle weaknesses, paralysis, and lack of proprioception. This often induces difficulty to perform everyday functions such as balancing. The goal of this project is to determine if stroke-like balance can be induced in healthy individuals. The Proprioceptive Interference Apparatus (PIA) applies vibrations and transcutaneous electrical nerve stimulation (TENS) about the knee joint in different combinations both with and without visual feedback. Ten subjects stood on one foot for periods of two minutes for each of the eight trial conditions. The root mean squared (RMS) of the position coordinates, the standard deviation of the forces, and the RMS of center of pressure coordinates were analyzed for each trial and subject. Analysis of the variation of position markers and forces showed a statistically significant difference between balance with visual feedback versus without. However, the use of PIA did not have any statistically significant difference on these measures.
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Shiraishi, Toshihiko, Kei Suzuki, Shin Morishita, and Hiroshi Kanno. "Control of Apoptosis and Differentiation of Cultured Neural Stem Cells by Mechanical Vibration." In ASME 2009 International Mechanical Engineering Congress and Exposition. ASMEDC, 2009. http://dx.doi.org/10.1115/imece2009-11154.
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In this study, sinusoidal inertia force was applied to cultured neural stem cells and the effects of mechanical vibration on the cells were investigated. Neural stem cells which were obtained from the hippocampus of an adult Fischer rat were seeded in culture plates at the density of 2.5 × 105 cells/ml. After cells were cultured for one day and adhered on the cultured plate, vibration groups of the culture plates were set on the aluminum plate of the experimental setup and cultured under sinusoidal excitation in another CO2 incubator separated from non-vibration groups of the culture plates. Acceleration amplitude was set to 0.25 or 0.5 G and frequency was set to 12.5, 25, or 50 Hz. Time evolution of cell density was obtained by counting the number of cells with a hemocytometer. The expression of Akt, phosphorylated Akt, MAPK, and phosphorylated MAPK was detected by western blotting analysis to understand the mechanism of cell proliferation. Gene expression of MAP-2, neurofilament-H, GFAP, and nestin was detected by a real-time RT-PCR method to obtain a ratio of differentiation of neural stem cells to nerve or glia cells. The results to be obtained are as follows. The mechanical vibration at 25 Hz is most effective on cell proliferation of the present experimental conditions at 0.25 G. The enhancement of cell proliferation is probably caused by the suppression of apoptosis. The differentiation of the neural stem cells depends on acceleration amplitude and the mechanical vibration may maintain some properties of stem cells.
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Whitcomb, Julie E., Vincent A. Barnett, Timothy W. Olsen, and Victor H. Barocas. "Iris Stiffening Following Drug Stimulation." In ASME 2007 Summer Bioengineering Conference. American Society of Mechanical Engineers, 2007. http://dx.doi.org/10.1115/sbc2007-176013.
Full textAbstract:
Glaucoma is a general term for the deterioration of the optic nerve head usually associated with an increase of intraocular pressure (IOP). Certain types of glaucoma are associated directly with the displacement of the iris from its normal morphology [1]. For example, angle closure glaucoma and pigment dispersion syndrome involve abnormal anterior or posterior displacement of the iris, respectively [2]. In angle closure, the abnormal position of the peripheral iris blocks aqueous humor access to the outflow pathway (trabecular meshwork), increasing the IOP. Although there has been a considerable amount of ultrastructural characterization of the iris [3], to our knowledge, there as been little done on the mechanical characterization of the iris other than a previous study by Heys and Barocas on passive bovine irides [4]. To have a complete understanding of these it requires that we understand the mechanical properties of the iris in both its passive and stimulated states. Mechanical analysis of the iris requires the consideration of its two constituent muscles, the inner sphincter iridis and the outer dilator pupillae, see Fig. 1. The sphincter iridis is innervated parasympathetically whereas the dilator is innervated sympathetically.
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Sakiyama, Ryota, Kazuya Matsumoto, Koji Yamamoto, Yusuke Morita, and Eiji Nakamachi. "Development of AC Magnetic Field Stimulation Bio-Reactor for Three-Dimensional Culture of PC12 Cells." In ASME 2017 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2017. http://dx.doi.org/10.1115/imece2017-70878.
Full textAbstract:
Recently, the electromagnetic stimulation method to enhance a nerve axonal extension has been attracting a great attention in the nerve regeneration. In this study, we design and fabricate a new 3D bio-reactor, which can implement uniform AC magnetic field (ACMF) stimulation on PC12 cells. We observe the morphology of PC12 cells using the multi photon microscope and evaluate effectiveness of uniform ACMF stimulation of the nerve axonal extension and the neural network generation. Firstly, a uniform ACMF stimulation bio-reactor was designed by using the pole piece structure. We searched an optimum structure using the magnetic field finite element analyses to obtain a uniform magnetic flux density in the culture region. Secondly, a chamber for 3D culture of PC12 cells was fabricated. PC12 cells were disseminated into a collagen gel which poured in the chamber. We evaluated the effects of uniform ACMF stimulation to enhance the nerve axonal extension. In our bio-reactor, an increase in axonal extension length and number of dendrites was observed under ACMF stimulation after 7 days culture. Finally, it was concluded that our uniform ACMF stimulation bio-reactor is an effective tool for the nerve axonal extension and the neural network generation.