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The physical mechanism underlying the mechanical behavior of glassy polymers has been studied over decades but remains a long-standing issue. A consensus view achieved is that the yield, flow, and stress relaxation behaviors are due to structural relaxation in the polymer mainly caused by chain conformation transitions. This is the key physical idea behind the many existing elastic-plastic constitutive models for glassy polymers. In this paper, such a constitutive model was employed for predicting and analyzing the stress relaxation of a glassy polymer. It is found that the model works well in predicting the pre-yield stress relaxation but significantly underestimates the post-yield stress relaxation. As considering the chain conformation transition alone leads to a dilemma for the model to concurrently represent the yield/flow and stress relaxation behaviors, the model was extended to incorporate an additional structural relaxation mechanism assumed to originate from the dissociation of weak linkages in the chain network. The extended model succeeds in concurrently representing the yield/flow, and stress relaxation behaviors in the whole deformation region, of which the reasons were analyzed. The knowledge revealed in this paper is instructive and may shed new light on understanding the structural relaxation and mechanical behavior of glassy polymers. KEYWORDS constitutive model, flow, glassy polymer, stress relaxation, yield, orcid.org/0000-0003-0621-4598 orcid.org/0000-0001-7864-0305 1 | INTRODUCTION An amorphous polymer in its glassy state is usually called a glassy polymer or polymer glass. Glassy polymers are solids with a high modulus and [...]

Forkhead box O transcriptional factors, especially FoxO1 and FoxO3a, play critical roles in physiologic and pathologic immune responses. However, the function of FoxO4, another main member of the FoxO family, in lymphoid cells is still poorly understood. Here, we showed that loss of FoxO4 in T cells augmented IFN-[gamma] production of Th1 cells in vitro. Correspondingly, conditional deletion of FoxO4 in CD4* T cells enhanced T cell-specific responses to Listeria monocytogenes infection in vivo. Genome-wide occupancy and transcriptomic analyses identified Dkk3 (encoding the Dickkopf-3 protein) as a direct transcriptional target of FoxO4. Consistent with the FoxO4-DKK3 relationship, recombinant DKK3 protein restored normal levels of IFN-[gamma] production in FoxO4-deficient Th1 cells through the downregulation of lymphoid enhancer-binding factor 1 (Left1) expression. Together, our data suggest a potential FoxO4/DKK3 axis in Th1 cell differentiation, providing what we believe to be an important insight and supplement for FoxO family proteins in T lymphocyte biology and revealing a promising target for the treatment of immune-related diseases., Introduction [CD4.sup.+] helper T cells are central regulators of adaptive immune responses. After encountering a specific antigen on antigen-presenting cells, [CD4.sup.+] T cells undergo clonal expansion and differentiate into functionally [...]

The coexistence of myo-inositol hexakisphosphate (IHP; phytate) and aqueous Zn(II) may affect the adsorbed amounts and speciation of each other on minerals, which can further influence the transport and fate of IHP and Zn(II) in soils and sediments. The objective of this study was to investigate the co-adsorption mechanism of IHP and Zn(II) on goethite (Gt). A combination of macroscopic experiments and in situ attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR) was used to investigate the co-adsorption of IHP and Zn(II) at the Gt-water interface in the pH range of 3.0-7.0. Adsorption experiments showed that the presence of IHP promoted Zn(II) adsorption, and vice versa, on the surface of Gt. The ATR-FTIR spectra of IHP adsorbed on Gt in the presence of Zn(II) differed from the spectra of IHP adsorbed without co-adsorbed Zn(II) and of zinc phytate (Zn-IHP) precipitates, suggesting that the formation of Gt-IHP-Zn ternary surface complexes was the most likely mechanism for the co-adsorption of IHP and Zn(II) on Gt. The results show that the coexistence of IHP and Zn(II) may have altered both the extent and mechanism of IHP and metal adsorption on Gt, with respect to binary Gt-IHP and Gt-Zn(II) systems. These findings indicate that the coexistence of IHP and heavy metals significantly affects the adsorbed amounts and speciation of these compounds in the natural environment, where the aqueous concentrations of reactants are below saturation with respect to metal phytate precipitates. Additional keywords: ATR-FTIR, co-adsorption, goethite, myo-inositol hexakisphosphate, Zn(II)., Introduction Numerous studies have shown that oxyanions can substantially affect adsorption of metals onto mineral surfaces, and vice versa (Elzinga et al. 2001; Zhang and Peak 2007; Elzinga and Kretzschmar [...]

Epigenetic regulators play critical roles in normal hematopoiesis, and the activity of these enzymes is frequently altered in hematopoietic cancers. The major type II protein arginine methyltransferase PRMT5 catalyzes the formation of symmetric dimethyl arginine and has been implicated in various cellular processes, including pluripotency and tumorigenesis. Here, we generated PrmtS conditional KO mice to evaluate the contribution of PRMT5 to adult hematopoiesis. Loss of PRMT5 triggered an initial but transient expansion of hematopoietic stem cells (HSCs); however, PrmtS deletion resulted in a concurrent loss of hematopoietic progenitor cells (HPCs), leading to fatal BM aplasia. PRMT5-specific effects on hematopoiesis were cell intrinsic and depended on PRMT5 methyltransferase activity. We found that PRMT5-deficient hematopoietic stem and progenitor cells exhibited severely impaired cytokine signaling as well as upregulation of p53 and expression of its downstream targets. Together, our results demonstrate that PRMT5 plays distinct roles in the behavior of HSCs compared with HPCs and is essential for the maintenance of adult hematopoietic cells., Introduction Homeostasis of blood cell production is sustained by a small pool of hematopoietic stem cells (HSCs), from which all mature blood cells are derived. These pluripotent HSCs must maintain [...]

The identification of somatic activating mutations in JAK2 (refs 1-4) and in the thrombopoietin receptor gene (MPL) (5) in most patients with myeloproliferative neoplasm (MPN) led to the clinical development [...]

BACKGROUND: In male rodents, anogenital distance (AGD) provides a sensitive and continuous correlate of androgen exposure in the intrauterine environment and predicts later reproductive success. Some endocrine-disrupting chemicals can alter [...]

Both historical (e.g., glaciations) and spatial (geological features) factors are considered to have had significant influences on the distribution and genetic structure of many plants. To understand the effects of such factors on the current genetic and geographical distributions of plant species in the Nanling and central regions in China, we examined genetic variation and phylogeographical patterns of Sagittaria lichuanensis J.K. Chen (Alismataceae), an endangered and endemic species in China, using chloroplast DNA atpB rbcL intergenic spacer sequence variation. In this study, a total of 9 haplotypes from 47 individuals in 6 populations of S. lichuanensis were detected. The [N.sub.ST] (0.193) was significantly higher than [G.sub.ST] (0.082) (P < 0.05), indicating a significant phylogeographical structure. In the minimum spanning network (MSN) of the haplotypes, the distribution of haplotypes showed an east-west split. The results of the Mantel test analysis showed that there was no correlation between the genetic distance and geographical distance (r = U.539, P > 0.05). The formation of barriers to dispersal might have played an important role in shaping the population genetic structure of S. lichuanensis. Within each region (east and west regions), high levels of gene How between populations and low levels of population differentiation were found. Several conditions, such as co-ancestry due to recent common ancestry or short period of isolation, might have occurred among the populations studied. In the MSN, all tip haplotypes except for two (A and G) occurred in two or more populations, and the haplotype D in the interior node was widespread. The haplotype D is likely to be an ancestral haplotype and represents the relic, widely distributed haplotype before the populations were fragmented and isolated by mountain uplift. Key words: atpB-rbcL, endemic, genetic variation, phylogeography, Sagittaria lichuanensis. On considere que les facteurs historiques (ex. glaciations) et spatiaux (caracteres geologiques) exercent des influences significatives sur la distribution ainsi que la structure genetique de nombreuses plantes. Afin de comprendre les effets de tels facteurs sur la genetique actuelle et les distributions geographiques d'especes vegetales de la region de Nanling et du centre de la Chine, les auteurs ont examine la variation genetique et les patrons phylogeographiques du Sagittaria lichuanensis J.K. Chen (Alismataceae), une espece endemique menacee de la Chine, en utilisant la variation des sequences de l'espaceur intergenique atpB-rbcL de l'ADN chloropl as tique. Dans cette elude, ils ont detecte un total de 9 haplotypes provenant de 47 individus issus de 6 populations du S. lichuanensis. Le [N.sub.ST] (0,193) etant significadvement plus grand que le [G.sub.ST] (0,082) (P < 0,05) indique une structure phylogeographique robuste. Dans le reseau d'etalement minimum (MSN) des haplotypes, la distribution des haplotypes montre une fracture est-ouest. Les resultats d'analyse du test de Mantel montrent l'absence de correlation entre la distance genetique et la distance geographique (r = 0,539, P > 0,05). La formation de barrieres a la dispersion pourrait avoir joue un role important pour faconner la structure de la population genetique du S. lichuanensis. Pour chaque region (regions est et ouest), on observe de forts flux de genes entre les populations et de faibles degres de differenciations des populations. II est possible que plusieurs conditions comme la co-descendance commune due a des ancetres communs recents ou de courtes periodes d'isolation soient survenues au sein des populations etudiees. Dans le MSN, on observe tous les haplotypes de pointe sauf deux haplotypes (A et G) dans deux ou plusieurs populations el l'haplolype D du noeud interieur est largement repandu. Il est probable que l'haplotype D soit un haplotype ancestral et represente un haplotype vestigial largement distribue avant la fragmentation des populations et l'isolation par l'emergence des montagnes. Mots-cles : atpB-rbcL, endemique, variation genetique, phylogeographie, Sagittaria lichuanensis. [Traduit par la Redaction], Introduction Investigating the level and distribution of genetic variation among natural populations could provide fundamental information on the evolutionary processes that bring about divergence within species and ultimately lead to [...]

BACKGROUND: Rodent and in vitro studies have demonstrated the estrogenicity of bisphenol A (BPA). However, few studies have examined the relationship between human exposure to BPA and male reproductive function. [...]

To ascertain more information on protein domain orientation and complex structure associations using chemical cross-linking, we have developed a combination of electrostatic collision-induced dissociative cross-linking reagents that differentiaily react with protein surfaces which are effectively analyzed by liquid chromatography-tandem mass spectrometry using ion trap multistage collision-induced dissociation. Implementing our original design and methodology based on disuccinimidyl-succinamyl-aspartyl-proline (SuDP) (Soderblom, E. J.; Goshe, M. B. Anal. Chem 2006, 78, 8059--8068. Soderblom, E. J.; Bobay, B. G.; Cavanagh, J.; Goshe, M. B. Rapid Commun Mass 8pectrom 2007, 21, 3395-3408.), disuccinimidyl-succinamyl-valyl-proline (SuVP) was synthesized. The SuDP and SuVP reagents are the same except for the valyl and aspartyl groups which provide a distinctive chemical feature to each reagent. When performing labeling reactions using various protein-to-cross-linker ratios at pH 7.5, the negatively charged SuDP and neutral SuVP were used to label bovine serum albumin and hemoglobin. After protein digestion, the resulting peptides were analyzed using four different ion trap LC/[MS.sup.3] acquisition methods incorporating multistage CID. The more polar BSA surface resulted in a number of unique interpeptide and intrapeptide cross-links for each reagent whereas the less polarized surface of hemoglobin produced similar results for both reagents. Based on the identification of dead-end products (i.e., a cross-link modification containing a hydrolyzed end) for each protein, the aminolysis reactivity of each modified lysyl side chain revealed a preference for reacting with each reagent according to its local electrostatic surface environment. Overall, combinatorial application of SuDP and SuVP chemical labeling produces a set of unique interpeptide, intrapeptide, and dead-end cross-linked products that provides protein structural information according to its electrostatic surface topology which has the potential to be used to more comprehensively probe protein structure and dynamics. 10.1021/ac101030w

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.ejor.2007.10.059 Byline: Fan-Yong Liu Abstract: This article has been retracted at the request of the Editor-in-Chief. Please see Elsevier Policy on Article Withdrawal (http://www.elsevier.com/locate/withdrawalpolicy). Reason: The author has plagiarized part of a paper that had already appeared in Comput. Oper. Res., 31 (2004) 1069–1081, doi:10.1016/S0305-0548(03)00065-0. One of the conditions of submission of a paper for publication is that authors declare explicitly that their work is original and has not appeared in a publication elsewhere. As such, this article represents a severe abuse of the scientific publishing system. The scientific community takes a very strong view on this matter and we apologize to readers of the journal that this was not detected during the submission process. Author Affiliation: School of Finance and Economics, Hangzhou Dianzi University, Hangzhou, Zhejiang 310018, PR China

Prenatal phthalate exposure impairs testicular function and shortens anogenital distance (AGD) in male rodents. We present data from the first study to examine AGD and other genital measurements in relation [...]

We previously reported reduced sperm concentration and motility in fertile men in a U.S. agrarian area (Columbia, MO) relative to men from U.S. urban centers (Minneapolis, MN; Los Angeles, CA; [...]

Although geographic variation in semen quality has been reported, this is the first study in the United States to compare semen quality among study centers using standardized methods and strict [...]

A theoretical study of the CH3NO2 unimolecular decomposition potential energy surface is presented. It also includes 46 interconversion transition states and 16 major dissociation products.

To test the hypothesis that American students have an advantage over East Asian students in arithmetical reasoning once computational abilities and IQ are controlled, 237 U.S. and 218 Chinese college students took arithmetical computational and reasoning tests, along with IQ and spatial abilities tests. Significant national differences favoring the Chinese students were found for all but the spatial test. After controlling for IQ and computational fluency, the Chinese advantage on the arithmetical reasoning tests was still significant but substantively smaller in magnitude. A similar pattern was observed for a sample of 55 U.S. and 80 Chinese high school students. The results, though not fully consistent with the hypothesis, are consistent with the position that the East Asian advantage in computational abilities contributes to the advantage in arithmetical reasoning.

Laser-induced nuclear magnetic resonance (NMR) shifts were investigated theoretically by semiclassic approach as a dynamic Stark effect of optical fields. Evidence showed that light shifts in an optical pumping experiment and in NMR and electron spin resonance spectra can be explained by the identical fundamental principle. The computed NMR shift for a Hg199 atom can be of the order of 1 MHz in a circularly polarized laser beam 10 W/sq cm at a frequency near the singlet-triplet transition absorption.

The electrocompression behavior of electrodeposited halide monolayer at the electrode surface of Au(111) may be investigated using a simple physical model and theory. Calculations of the statistical thermodynamic formulas, effective pair interaction energy, two dimensional spreading pressure, two dimensional isothermal compressibility and electrode potential-coverage yield results that are in agreement with experimental measurements. The calculations show that the adatom-adatom interactions, such as repulsive interactions, determine the compressibility of the halide adlayer.

Author(s): Priya Koppikar [1, 9]; Neha Bhagwat [1, 2, 9]; Outi Kilpivaara [1, 9]; Taghi Manshouri [3]; Mazhar Adli [4]; Todd Hricik [1]; Fan Liu [5]; Lindsay M. Saunders [1, [...]

Ref.: Botany, 88(10): 886-892 (2010). In the above paper, the following error occurred: The corresponding information for Qing-Feng Wang and the initals for Shu-Ying Zhao, Jin-Ming Chen, and Qing-Feng Wang [...]