Bifurcation analysis based on a material model with stress-rate dependency and non-associated flow rule for fracture prediction in metal forming

Recent increasing application of advanced high-strength metals causes grow-ing demand for accurate fracture prediction in metal forming simulation. However, since the construction of objective and reliable fracture prediction method is generally difficult, essential progress in fundamental theory that supports evolution of fracture rediction framework is required. In this study, a fracture prediction framework based on the bifurcation theory is pre- sented. The main achievement is a novel material model based on stress-rate dependency related with non-associate flow rule. This model is based on non-associated flow rule with independent arbitrary higher-order yield function and plastic potential function for any anisotropic materials. And this formulation is combined with the stress-rate depen- dency plastic constitutive equation, which is known as Ito-Goya model, to construct a generalized plastic constitutive model in which non-normality and non-associativity are reasonably considered. Then, by adopting the three-dimensional bifurcation theory, which is known as the 3D localized bifurcation theory, more accurate prediction of the initiation of shear band is realized, leading to general and reliable construction of forming limit dia- gram. Then, by using virtual material data, numerical simulation is carried out to exhibit fracture limit diagram for demonstrating the generality and reliability of the proposed methodology. In particular, the effect of stress-rate dependency on the bifurcation analy- sis is investigated, and the order of the yield function is used to investigate the influence on the forming limit prediction

Divergence of male courtship displays between sympatric forms of anadromous threespine stickleback

Courtship displays are an important component of animal reproduction, and divergence in these displays can play an integral role in promoting or maintaining reproductive isolation between species. The courtship behaviour of the threespine stickleback (Gasterosteus aculeatus) has been extensively characterized. In Japan, there are two lineages of threespine stickleback that are genetically differentiated and reproductively isolated when found in regions of sympatry. We have previously shown that males of the Pacific Ocean lineage perform the zig-zag dance, while sympatric males of the Japan Sea lineage perform a different dance, which we have termed the rolling dance (Kitano et al., 2007, Biol. J. Linn. Soc. 91: 671-685). As a first step towards understanding the role of the courtship display in female mate choice and sexual isolation between this sympatric pair, we conducted a more detailed analysis of divergence between the courtship displays of the Pacific Ocean and Japan Sea males. Kinematic analysis revealed that the tempo of the zig-zag dance is two times faster than the tempo of the rolling dance. A detailed analysis of head movements during the courtship dance revealed that the Japan Sea males erect their gill covers, extend their red throats, and open their mouths more frequently during the rolling dance than the Pacific Ocean males do during the zig-zag dance. These results demonstrate that there is extensive divergence between sympatric Pacific Ocean and Japan Sea males in both the motor patterns and the tempo of their courtship displays. Thus, the Japanese sympatric stickleback pair provides a good system to study the role of courtship behaviour in speciation, as well as the genetic mechanisms that underlie the divergence of kinematics and motor patterns in courtship behaviour

Phenotypic divergence and reproductive isolation between sympatric forms of Japanese threespine sticklebacks

The threespine stickleback (Gasterosteus aculeatus) species complex is well suited for identifying the types of phenotypic divergence and isolating barriers that contribute to reproductive isolation at early stages of speciation. In the present study, we characterize the patterns of genetic and phenotypic divergence as well as the types of isolating barriers that are present between two sympatric pairs of threespine sticklebacks in Hokkaido, Japan. One sympatric pair consists of an anadromous and a resident freshwater form and shows divergence in body size between the forms, despite the lack of genetic differentiation between them. The second sympatric pair consists of two anadromous forms, which originated before the last glacial period and are currently reproductively isolated. These two anadromous forms have diverged in many morphological traits as well as in their reproductive behaviours. Both sexual isolation and hybrid male sterility contribute to reproductive isolation between the anadromous species pair. We discuss the shared and unique aspects of phenotypic divergence and reproductive isolation in the Japanese sympatric pairs compared with postglacial stickleback species pairs. Further studies of these divergent species pairs will provide a deeper understanding of the mechanisms of speciation in sticklebacks. © 2007 The Linnean Society of London, Biological Journal of the Linnean Society, 2007, 91, 671–685

Thyroid Hormone Receptor alpha-1 Directly Controls Transcription of the beta-Catenin Gene in Intestinal Epithelial Cells

Thyroid hormones, T3 and T4, are known regulators of intestine development. The best characterized example is the remodeling of the gastrointestinal tract during amphibian metamorphosis. Thyroid hormones act via nuclear receptors, the TRs, which are T3-dependent transcription factors. We previously showed that intestinal epithelial cell proliferation is controlled by thyroid hormones and the TRalpha gene. To analyze the mechanisms responsible, we studied the expression of genes belonging to and/or activated by the Wnt/beta-catenin pathway, a major actor in the control of physiological and pathological epithelial proliferation in the intestine. We show that T3-TR1 controls the transcription of the beta-catenin gene in an epithelial cell-autonomous way. This is parallel to positive regulation of proliferation-controlling genes such as type D cyclins and c-myc, known targets of the Wnt/-beta-catenin. In addition, we show that the regulation of the beta-catenin gene is direct, as TR binds in vitro and in chromatin in vivo to a specific thyroid hormone-responsive element present in intron 1 of this gene. This is the first report concerning in vivo transcriptional control of the beta-catenin gene. As Wnt/beta-catenin plays a crucial role in intestinal tumorigenesis, our observations open a new perspective on the study of TRs as potential tumor inducers

Force correlations in molecular and stochastic dynamics

A molecular gas system in three dimensions is numerically studied by the energy conserving molecular dynamics (MD). The autocorrelation functions for the velocity and the force are computed and the friction coefficient is estimated. From the comparison with the stochastic dynamics (SD) of a Brownian particle, it is shown that the force correlation function in MD is different from the delta-function force correlation in SD in short time scale. However, as the measurement time scale is increased further, the ensemble equivalence between the microcanonical MD and the canonical SD is restored. We also discuss the practical implication of the result.Comment: 9 pages, 4 figures and Computer Physics Communcations (in press

Accuracy of Articulation Rate Control with Visual Feedback in Persons who do and do not Stutter

AbstractThe ability to control speech rate with real-time visual feedback was compared between people who do and do not stutter (PWS/PWNS). Nine PWS and 7 PWNS participated in the study. Fifteen sentences were read aloud after repeating a played-back sentence twice in each of 6 trials at 6 different target speeds. The 6 trials comprise a session, and there were 3 sessions (A1, B, A2) with only the second session (B) accompanied by real-time visual feedback of the subject's speech rate and the target speed. The speech rate excluding pauses or dysfluencies was significantly reduced in B and A2 from that in session A1. Although there was no difference in speech rate between B and A2, (a) there was an interaction between the target rate and the group in session B, and (b) the variability in the error of the PWS was larger than that of the PWNS in the retention session (A2). These results suggests (a) that at least some of the PWS use a different strategy in controlling their speech rate than PWNS, and (b) that some of the PWS were less accurate in retaining the learned speech rate in the previous session B with visual feedback than the PWNS, although they did use the visual feedback information and learned the speech rate, to a similar averaged accuracy during the feedback

Identification of the nuclear export signal in the helix–loop–helix inhibitor Id1

AbstractId proteins play important roles in cellular differentiation and proliferation by negatively regulating basic helix–loop–helix transcription factors. Although their intracellular localization may change depending on the biological situation, little is known about the molecular determinants underlying such changes. Here we report the identification of a nuclear export signal (NES) in Id1. The identified NES was different from that of Id2, but had the ability to confine heterologous green fluorescent protein to the cytoplasm. Thus, our results indicate that the intracellular localization of Id1 is regulated differently from that of Id2

A dominant-negative FGF1 mutant (the R50E mutant) suppresses tumorigenesis and angiogenesis.

Fibroblast growth factor-1 (FGF1) and FGF2 play a critical role in angiogenesis, a formation of new blood vessels from existing blood vessels. Integrins are critically involved in FGF signaling through crosstalk. We previously reported that FGF1 directly binds to integrin αvβ3 and induces FGF receptor-1 (FGFR1)-FGF1-integrin αvβ3 ternary complex. We previously generated an integrin binding defective FGF1 mutant (Arg-50 to Glu, R50E). R50E is defective in inducing ternary complex formation, cell proliferation, and cell migration, and suppresses FGF signaling induced by WT FGF1 (a dominant-negative effect) in vitro. These findings suggest that FGFR and αvβ3 crosstalk through direct integrin binding to FGF, and that R50E acts as an antagonist to FGFR. We studied if R50E suppresses tumorigenesis and angiogenesis. Here we describe that R50E suppressed tumor growth in vivo while WT FGF1 enhanced it using cancer cells that stably express WT FGF1 or R50E. Since R50E did not affect proliferation of cancer cells in vitro, we hypothesized that R50E suppressed tumorigenesis indirectly through suppressing angiogenesis. We thus studied the effect of R50E on angiogenesis in several angiogenesis models. We found that excess R50E suppressed FGF1-induced migration and tube formation of endothelial cells, FGF1-induced angiogenesis in matrigel plug assays, and the outgrowth of cells in aorta ring assays. Excess R50E suppressed FGF1-induced angiogenesis in chick embryo chorioallantoic membrane (CAM) assays. Interestingly, excess R50E suppressed FGF2-induced angiogenesis in CAM assays as well, suggesting that R50E may uniquely suppress signaling from other members of the FGF family. Taken together, our results suggest that R50E suppresses angiogenesis induced by FGF1 or FGF2, and thereby indirectly suppresses tumorigenesis, in addition to its possible direct effect on tumor cell proliferation in vivo. We propose that R50E has potential as an anti-cancer and anti-angiogenesis therapeutic agent ("FGF1 decoy")

Clinical perspectives of Treponema pallidum subsp. Endemicum infection in adults, particularly men who have sex with men in the Kansai area, Japan: A case series

Bejel, caused by Treponema pallidum subsp. Endemicum (TEN), is a locally transmitted disease among children and juveniles in hot and dry regions. The number of adult cases of TEN infection outside of endemic areas has recently increased. We clinically examined five cases of TEN infection among adult cases previously reported in Japan. TEN infection mainly developed among young to middle-aged men who have sex with men (MSM). The clinical features of cases of TEN infection were similar to those of primary- and secondary-stage T. pallidum subsp. pallidum (TPA) infection. Genital lesions were common as the primary lesion. The clinical features and laboratory parameters of cases of TEN infection were similar to those of TPA infection. Most of the isolated strains had the A2058G mutation in 23S rDNA, which is responsible for resistance to macrolides. We also performed the systemic literature review of the TEN cases outside the endemic countries. The recent reported cases diagnosed with molecular methods shared the clinical features, occurred in young-to middle-aged sexually active persons in urban areas of developed countries and often accompanied with genital lesions, which were distinct from the classic description of bejel. This case series and the literature review provides important clinical insights and will contribute to the clinical detection of this rarely identified disease in developed countries. The surveillance of treponematoses, including TEN infection, using molecular diagnostic techniques is also warranted in developed countries, for the purpose of grasping the epidemic situation and control the local transmission