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Dynamic Function (dynamic + function)
Selected AbstractsFibre type composition of the human psoas major muscle with regard to the level of its originJOURNAL OF ANATOMY, Issue 6 2009Juraj Arbanas Abstract The aim of our study was to explore the fibre type composition of the human psoas major muscle at different levels of its origin, from the first lumbar to the fourth lumbar vertebra, and to compare the muscle fibre size and distribution of different fibre types between levels with respect to its complex postural and dynamic function. Muscle samples were collected from 15 young males (younger than 35 years). Serial transverse sections (5 ,m) of the samples were cut by cryomicrotome. Type I, IIA and IIX muscle fibres were typed using myosin heavy chain identification. The serial sections were analysed using a light microscope with a magnitude of 100×. The differences between measurements were evaluated using a repeated-measures anova and Scheffé test for post-hoc analysis. Our study showed that the human psoas major muscle was composed of type I, IIA and IIX muscle fibres. It had a predominance of type IIA muscle fibres, whereas type I muscle fibres had the largest cross-sectional area. Type IIX muscle fibres were present as a far smaller percentage and had the smallest cross-sectional area. Moreover, the fibre type composition of the psoas major muscle was different between levels of its origin starting from the first lumbar to the fourth lumbar vertebra. We conclude that the fibre type composition of the psoas major muscle indicated its dynamic and postural functions, which supports the fact that it is the main flexor of the hip joint (dynamic function) and stabilizer of the lumbar spine, sacroiliac and hip joints (postural function). The cranial part of the psoas major muscle has a primarily postural role, whereas the caudal part of the muscle has a dynamic role. [source] Confocal microscopy of the light organ crypts in juvenile Euprymna scolopes reveals their morphological complexity and dynamic function in symbiosisJOURNAL OF MORPHOLOGY, Issue 5 2006Laura K. Sycuro Abstract In the hours to days following hatching, the Hawaiian bobtail squid, Euprymna scolopes, obtains its light-emitting symbiont, Vibrio fischeri, from the surrounding environment and propagates the bacteria in the epithelial crypts of a specialized light organ. Three-dimensional analyses using confocal microscopy revealed that each of the three crypts on either side of the juvenile light organ is composed of four morphological regions. Progressing from the lateral pore to the medial blind end of each crypt, the regions consist of 1) a duct, 2) an antechamber, 3) a bottleneck, and 4) a deep region. Only the deep region houses a persistent bacterial population, whereas the duct, antechamber, and bottleneck serve as conduits through which the bacteria enter during initial colonization and exit during diel venting, a behavior in which ,90% of the symbionts are expelled each dawn. Our data suggest that, like the duct, the antechamber and bottleneck may function to promote and maintain the specificity of the symbiosis. Pronounced structural and functional differences among the deep regions of the three crypts, along with previously reported characterizations of embryogenesis, suggest a continued developmental progression in the first few days after hatching. Taken together, the results of this study reveal a high degree of complexity in the morphology of the crypts, as well as in the extent to which the three crypts and their constituent regions differ in function during the early stages of the symbiosis. J. Morphol. © 2006 Wiley-Liss, Inc. [source] Optimization of Autologous Muscle Stem Cell Survival in the Denervated Hemilarynx,THE LARYNGOSCOPE, Issue 7 2008Stacey L. Halum MD Abstract Objective: Current treatments for vocal fold paralysis are suboptimal in that they fail to restore dynamic function. Autologous muscle stem cell (MSC) therapy is a promising potential therapy for vocal fold paralysis in that it can attenuate denervation-induced muscle atrophy and provide a vehicle for delivery of neurotrophic factors, thereby potentially selectively guiding reinnervation. The goal of this project was to characterize optimal conditions for injected autologous MSC survival in the thyroarytenoid (TA) muscle following recurrent laryngeal nerve (RLN) injury by local administration of adjuvant factors. Study Design: Animal experiment. Methods: Unilateral RLN transection and sternocleidomastoid muscle (,1 g) biopsies were performed in 20 male Wistar rats. One month later, 106 autologous MSCs labeled via retroviral-enhanced green fluorescent protein (EGFP) transduction were injected into the denervated hemilarynx of each animal with one of four adjuvant therapies: cardiotoxin [(CTX) 10,5 M], insulin-like growth factor-1 [(IGF- 1) 100 ,g/mL], ciliary neurotrophic factor [(CNTF) 50 ,g/mL], or saline. Animals were euthanized 1 month later and larynges harvested, sectioned, and analyzed for MSC survival. Results: All specimens demonstrate extensive MSC survival, with fusion of the MSCs with the denervated myofibers. Based on mean fluorescent intensity of the laryngeal specimens, IGF-1 and CNTF had the greatest positive influence on MSC survival. Myofiber diameters demonstrated myofiber atrophy to be inversely related to MSC survival, with the least atrophy in the groups having the greatest MSC survival. Conclusions: Autologous MSC therapy may be a future treatment for vocal fold paralysis. These findings support a model whereby MSCs genetically engineered to secrete CNTF and/or IGF-1 may not only promote neural regeneration, but also enhance MSC survival in an autocrine fashion. [source] Absence of the medial sesamoid bone associated with metatarsophalangeal painCLINICAL ANATOMY, Issue 7 2006Ulunay Kanatli Abstract Pain at the first metatarsophalangeal (MTP) joint can result from inflammation, chondromalacia, flexor hallucis brevis tendinitis, osteochondritis dessecans, fracture of a sesamoid bone, avascular necrosis of sesamoids, inflamed bursae, intractable keratoses, infection, sesamoiditis, gout arthropathy, and rheumatoid arthritis. Congenital absence of a sesamoid bone is extremely rare. We present a 17-year-old male patient with pain at the plantar aspect of the right MTP joint associated with congenital absence of the medial sesamoid. There was tenderness and the range of motion was minimally restricted. He described the pain as necessitating changes in his social life. On radiographs, the medial hallucial sesamoid was absent on the right side. The MTP joint was also evaluated using magnetic resonance imaging (MRI). A metatarsal pad was prescribed and the patient was satisfied with the treatment at the 2 months follow-up period. MRI revealed no pathological tissue at the medial sesamoid site. Hallucial sesamoids absorb pressure, reduce friction, protect the tendons, act like a fulcrum to increase the mechanical force of the tendons, and provide a dynamic function to the great toe by elevating first metatarsal head. Congenital absence of these bones is very rare but we must consider it in a patient with MTP joint pain. Clin. Anat. 19:634,639, 2006. © 2006 Wiley-Liss, Inc. [source] Structural topology optimization of vibrating structures with specified eigenfrequencies and eigenmode shapesINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN ENGINEERING, Issue 5 2006Y. Maeda Abstract In vibration optimization problems, eigenfrequencies are usually maximized in the optimization since resonance phenomena in a mechanical structure must be avoided, and maximizing eigenfrequencies can provide a high probability of dynamic stability. However, vibrating mechanical structures can provide additional useful dynamic functions or performance if desired eigenfrequencies and eigenmode shapes in the structures can be implemented. In this research, we propose a new topology optimization method for designing vibrating structures that targets desired eigenfrequencies and eigenmode shapes. Several numerical examples are presented to confirm that the method presented here can provide optimized vibrating structures applicable to the design of mechanical resonators and actuators. Copyright © 2006 John Wiley & Sons, Ltd. [source] DYNAMIC MODELING OF RETORT PROCESSING USING NEURAL NETWORKSJOURNAL OF FOOD PROCESSING AND PRESERVATION, Issue 2 2002C. R. CHEN ABSTRACT Two neural network approaches , a moving-window and hybrid neural network , which combine neural network with polynomial regression models, were used for modeling F(t) and Qv(t) dynamic functions under constant retort temperature processing. The dynamic functions involved six variables: retort temperature (116,132C), thermal diffusivity (1.5,2.3 × 10,7m2/s), can radius (40,61 mm), can height (40,61 mm), and quality kinetic parameters z (15,39C) and D (150,250 min). A computer simulation designed for process calculations of food thermal processing systems was used to provide the fundamental data for training and generalization of ANN models. Training data and testing data were constructed by both second order central composite design and orthogonal array, respectively. The optimal configurations of ANN models were obtained by varying the number of hidden layers, number of neurons in hidden layer and learning runs, and a combination of learning rules and transfer function. Results demonstrated that both neural network models well described the F(t) and Qv(t) dynamic functions, but moving-window network had better modeling performance than the hybrid ANN models. By comparison of the configuration parameters, moving-window ANN models required more neurons in the hidden layer and more learning runs for training than the hybrid ANN models. [source] Myelin proteolipid protein, basic protein, the small isoform of myelin-associated glycoprotein, and p42MAPK are associated in the Triton X-100 extract of central nervous system myelinJOURNAL OF NEUROSCIENCE RESEARCH, Issue 1 2002Dina N. Arvanitis Abstract To further our understanding of the functions of the major myelin proteins, myelin basic protein (MBP) and proteolipid protein (PLP), and other myelin proteins, such as 2,3,-cyclic nucleotide 3,-phosphodiesterase (CNP) and myelin-associated glycoprotein (MAG), bovine brain myelin was extracted with Triton X-100, and protein complexes in the detergent-soluble fraction were isolated by coimmunoprecipitation and sucrose density gradient sedimentation. MBP, PLP, and the small isoform of MAG (S-MAG) were coimmunoprecipitated from the detergent-soluble fraction by anti-PLP, anti-MBP or anti-MAG monoclonal antibodies. Additionally, a 30 kDa phosphoserine-containing protein and two phosphotyrosine-containing proteins (Mr 30 and 42 kDa) were found in the coimmunoprecipitates. The 42 kDa protein is probably p42MAPK, in that MAPK was shown also to be present in the immunoprecipitated complex. CNP, the small PLP isoform DM20, the large MAG isoform L-MAG, MOG, CD44, MEK, p44MAPK, and actin were not present in the immunoprecipitates, although they were present in the detergent-soluble fraction. Lipid analysis revealed that the PLP,MBP,S-MAG coimmunoprecipitated with some phospholipids and sulfatide but not cholesterol or galactosylceramide. However, the complex had a high density, indicating that the lipid/protein ratio is low, and it was retained on a Sepharose CL6B column, indicating that it is not a large membrane fragment. Given that MAG is localized mainly in the periaxonal region of myelin, where it interacts with axonal ligands, the PLP,MBP,S-MAG complex may come from these regions, where it could participate in dynamic functions in the myelin sheath and myelin,axonal interactions. © 2002 Wiley-Liss, Inc. [source] | ||||||||||