3-Dimensional Stress Calculation of Competitive Swimwear Using Anisotropic Hyperelastic Model Considering Stress Softening

AbstractThree dimensional stress calculation of competitive swimwear using anisotropic hyperelastic model considering stress softening was investigated in this paper. An anisotropic hyperelastic model considering stress softening of swimwear fabrics was introduced in order to reproduce the mechanical characteristics of swimwear fabrics on the analysis. The cyclic tensile loading test was carried out to evaluate the mechanical characteristics of the swimwear fabrics. From the test results, the mechanical characteristics of swimwear fabrics show strong-anisotropy and the stiffness of the fabrics shows hardening along with the increase of stretch. Also, the test results show reduction of stiffness which depended on the maximum deformation previously reached in the history of the swimwear fabrics. From the test results, material parameters of the anisotropic hyperelastic model and the stress softening model were approximated. The theoretical calculations were in good agreements with experimental data. In addition, the pressure measurement tests were conducted to measure the pressure of swimwear tightening the cylinder. The theoretical pressure calculated by the proposed model showed similar trend of pressure measurement tests. Finally, 3-dimentional stress calculation of swimwear was conducted using the anisotropic hyperelastic model considering stress softening. The stress calculation enabled the visualization of stress distributions of swimwear. In addition, the torque generated in right and left hip joints were calculated by stress calculation of swimwear. The stress calculation investigated in this study enabled the new design of competitive swimwear considering the torque generated in hip joint

Preliminary Experiment on the Plasma Confinement in the Heliotron Field with Buried Ring Conductors

In order to restore the plasma stability in the Heliotron C magnetic field, the Heliotron-P field, which has buried ring conductors inside the vacuum vessel and thus avoids the cusp losses, has been proposed. As a preliminary experiment on the plasma confinement in this field, the plasma behaviour in a mirror field having a current carrying ring conductor, which corresponds to the one section of the Heliotron-P field, is investigated. The plasma injected from a gun into this field rapidly fills up the region near the separatrix showing the existence of the magnetic well. The plasma ( Tₑ≃20 eV, Tₑ≤11 eV, n?10¹1) is stably confined in this field. The predominant loss is the mirror end loss, and the net radial loss time is inferred to be 1.4 msec. Drift instability is observed only in the region of the steep density gradient at the plasma periphery

A New Method for Designing Sportswear by Using Three Dimensional Computer Graphic Based Anisotropic Hyperelastic Models and Musculoskeletal Simulations

AbstractThe purpose of this study is to develop a new method for designing compression sportswear from the viewpoint of force by simulation. Applied simulation techniques are 1) skin strain simulation, 2) fabric strain simulation using the anisotropic hyperelastic model, and 3) musculoskeletal simulation. For skin strain simulations, a three dimensional computer graphic (3D-CG) polygon strain was calculated as a skin strain using a 3D-CG model that simulates the human body (CG-Human-Model). The initial strain and the strain caused by physical exercise were given to the polygon model representing the shape of the sportswear (CG-Sportswear-Model). For compression sportswear, the strain of the fabric is approximately the same as skin strain, thus the strain of the CG-Human-Model was given to the CG-Sportswear-Model. In-plane and out-of-plane forces resulting from the CG-Sportswear-Model are calculated using anisotropic hyperelastic models. These forces were given to the musculoskeletal simulation as the external forces, and muscle activity required for any given physical exercise (e.g. swimming motion) was calculated. Information of forces and muscle activity are very useful in designing compression sportswear. It is believed that this new method for designing compression sportswear based on simulation is a sophisticated technique because this method takes into account not only forces resulting from sportswear but also the effect of these forces on physical exercise

The adenosine A2B receptor is involved in anion secretion in human pancreatic duct Capan-1 epithelial cells

Adenosine modulates a wide variety of biological processes via adenosine receptors. In the exocrine pancreas, adenosine regulates transepithelial anion secretion in duct cells and is considered to play a role in acini-to-duct signaling. To identify the functional adenosine receptors and Cl− channels important for anion secretion, we herein performed experiments on Capan-1, a human pancreatic duct cell line, using open-circuit Ussing chamber and gramicidin-perforated patch-clamp techniques. The luminal addition of adenosine increased the negative transepithelial potential difference (V te) in Capan-1 monolayers with a half-maximal effective concentration value of approximately 10 μM, which corresponded to the value obtained on whole-cell Cl− currents in Capan-1 single cells. The effects of adenosine on V te, an equivalent short-circuit current (I sc), and whole-cell Cl− currents were inhibited by CFTRinh-172, a cystic fibrosis transmembrane conductance regulator (CFTR) Cl− channel inhibitor. The adenosine A2B receptor agonist, BAY 60-6583, increased I sc and whole-cell Cl− currents through CFTR Cl− channels, whereas the A2A receptor agonist, CGS 21680, had negligible effects. The A2B receptor antagonist, PSB 603, inhibited the response of I sc to adenosine. Immunohistochemical analysis showed that the A2A and A2B receptors colocalized with Ezrin in the luminal membranes of Capan-1 monolayers and in rat pancreatic ducts. Adenosine elicited the whole-cell Cl− currents in guinea pig duct cells. These results demonstrate that luminal adenosine regulates anion secretion by activating CFTR Cl− channels via adenosine A2B receptors on the luminal membranes of Capan-1 cells. The present study endorses that purinergic signaling is important in the regulation of pancreatic secretion

Involvement of butyrate in electrogenic K+ secretion in rat rectal colon

Short-chain fatty acids (SCFAs), such as acetate, propionate, and butyrate, are synthesized from dietary carbohydrates by colonic bacterial fermentation. These SCFAs supply energy, suppress cancer, and affect ion transport. However, their roles in ion transport and regulation in the intracellular environment remain unknown. In order to elucidate the roles of SCFAs, we measured short-circuit currents (ISC) and performed RT-PCR and immunohistochemical analyses of ion transporters in rat rectal colon. The application of 30 mM butyrate shifted ISC in a negative direction, but did not attenuate the activity of epithelial Na+ channels (ENaC). The application of bumetanide, a Na+-K+-2Cl− cotransporter inhibitor, to the basolateral side reduced the negative ISC shift induced by butyrate. The application of XE991, a KCNQ-type K+ channel inhibitor, to the apical side decreased the ISC shift induced by butyrate in a dose-dependent manner. The ISC shift was independent of HCO3− and insensitive to ibuprofen, an SMCT1 inhibitor. The mucosa from rat rectal colon expressed mRNAs of H+-coupled monocarboxylate transporters (MCT1, MCT4, and MCT5, also referred to as SLC16A1, SLC16A3, and SLC16A4, respectively). RT-PCR and immunofluorescence analyses demonstrated that KCNQ2 and KCNQ4 localized to the apical membrane of surface cells in rat rectal colon. These results indicate that butyrate, which may be transported by H+-coupled monocarboxylate transporters, activates K+ secretion through KCNQ-type K+ channels on the apical membrane in rat rectal colon. KCNQ-type K+ channels may play a role in intestinal secretion and defense mechanisms in the gastrointestinal tract

C-type Natriuretic Peptide–induced PKA Activation Promotes Endochondral Bone Formation in Hypertrophic Chondrocytes

Longitudinal bone growth is achieved by a tightly controlled process termed endochondral bone formation. C-type natriuretic peptide (CNP) stimulates endochondral bone formation through binding to its specific receptor, guanylyl cyclase (GC)-B. However, CNP/GC-B signaling dynamics in different stages of endochondral bone formation have not been fully clarified, especially in terms of the interaction between the cyclic guanine monophosphate (cGMP) and cyclic adenosine monophosphate (cAMP) pathways. Here, we demonstrated that CNP activates the cAMP/protein kinase A (PKA) pathway and that this activation contributed to the elongation of the hypertrophic zone in the growth plate. Cells of the chondrogenic line ATDC5 were transfected with Förster resonance energy transfer (FRET)–based cGMP and PKA biosensors. Dual-FRET imaging revealed that CNP increased intracellular cGMP levels and PKA activities in chondrocytes. Further, CNP-induced PKA activation was enhanced following differentiation of ATDC5 cells. Live imaging of the fetal growth plate of transgenic mice, expressing a FRET biosensor for PKA, PKAchu mice, showed that CNP predominantly activates the PKA in the hypertrophic chondrocytes. Additionally, histological analysis of the growth plate of PKAchu mice demonstrated that CNP increased the length of the growth plate, but coadministration of a PKA inhibitor, H89, inhibited the growth-promoting effect of CNP only in the hypertrophic zone. In summary, we revealed that CNP-induced cGMP elevation activated the cAMP/PKA pathway, and clarified that this PKA activation contributed to the bone growth–promoting effect of CNP in hypertrophic chondrocytes. These results provide insights regarding the cross-talk between cGMP and cAMP signaling in endochondral bone formation and in the physiological role of the CNP/GC-B system

C-type natriuretic peptide-induced PKA activation promotes endochondral bone formation in hypertrophic chondrocytes

Longitudinal bone growth is achieved by a tightly controlled process termed endochondral bone formation. C-type natriuretic peptide (CNP) stimulates endochondral bone formation through binding to its specific receptor, guanylyl cyclase (GC)-B. However, CNP/GC-B signaling dynamics in different stages of endochondral bone formation have not been fully clarified, especially in terms of the interaction between the cyclic guanine monophosphate (cGMP) and cyclic adenosine monophosphate (cAMP) pathways. Here, we demonstrated that CNP activates the cAMP/protein kinase A (PKA) pathway and that this activation contributed to the elongation of the hypertrophic zone in the growth plate. Cells of the chondrogenic line ATDC5 were transfected with Förster resonance energy transfer (FRET)–based cGMP and PKA biosensors. Dual-FRET imaging revealed that CNP increased intracellular cGMP levels and PKA activities in chondrocytes. Further, CNP-induced PKA activation was enhanced following differentiation of ATDC5 cells. Live imaging of the fetal growth plate of transgenic mice, expressing a FRET biosensor for PKA, PKAchu mice, showed that CNP predominantly activates the PKA in the hypertrophic chondrocytes. Additionally, histological analysis of the growth plate of PKAchu mice demonstrated that CNP increased the length of the growth plate, but coadministration of a PKA inhibitor, H89, inhibited the growth-promoting effect of CNP only in the hypertrophic zone. In summary, we revealed that CNP-induced cGMP elevation activated the cAMP/PKA pathway, and clarified that this PKA activation contributed to the bone growth–promoting effect of CNP in hypertrophic chondrocytes. These results provide insights regarding the cross-talk between cGMP and cAMP signaling in endochondral bone formation and in the physiological role of the CNP/GC-B system

Spin and chirality orderings of the one-dimensional Heisenberg spin glass with the long-range power-law interaction

The ordering of the one-dimensional Heisenberg spin glass interacting via the long-range power-law interaction is studied by Monte Carlo simulations. Particular attention is paid to the possible occurrence of the ``spin-chirality decoupling'' for appropriate values of the power-law exponent \sigma. Our result suggests that, for intermediate values of $\sigma$, the chiral-glass order occurs at finite temperatures while the standard spin-glass order occurs only at zero temperature.Comment: Proceedings of the Highly Frustrated Magnetism (HFM2006) conference. To appear in a special issue of J. Phys. Condens. Matte