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Impaired pancreatic β-cell function is the primary defect in type 2 diabetes. Glucose is an important regulator of β-cell growth and function; however, the mechanisms that are involved in the chronic adaptation of β cells to hyperglycemia remain largely unknown. In the present study, global gene expression patterns revealed that tryptophan hydroxylase 1 (

We consider a class of second order Hamiltonian systems with a $C^{2}$ potential function. The existence of new periodic solutions with a prescribed energy is established by the use of constrained variational methods.

Previous research has shown that perceptual information such as font size has an impact on learners' judgments of their own learning. The present study extended the font-size effect to examine the influence of font size on how people decide which items to study first. Across three experiments, we showed that participants preferred to first select items presented in a large font size (48 pt) more than items presented in a small font size (18 pt), and that this effect continued even when more diagnostic cues (difficulty and reward value of items) were presented, suggesting that perceptual cues can strongly influence control process involved in self-regulated learning. These results provide evidence that perceptual information plays a key role in higher cognition. Moreover, our results also suggest that control processes are influenced by multiple cues, including font size, difficulty of items, and the reward value of items.

Quantitative reverse transcription PCR (qRT-PCR) is becoming increasingly important in the effort to gain insight into the molecular mechanisms underlying adipogenesis. However, the expression profile of a target gene may be misinterpreted due to the unstable expression of the reference genes under different experimental conditions. Therefore, in this study, we investigated the expression stability of 10 commonly used reference genes during 3T3-L1 adipocyte differentiation. The mRNA expression levels of glyceraldehyde-3-phosphate dehydrogenase (GAPDH) and transferrin receptor (TFRC) significantly increased during the course of 3T3-L1 adipocyte differentiation, which was decreased by berberine, an inhibitor of adipogenesis. Three popular algorithms, GeNorm, NormFinder and BestKeeper, identified 18 ribosomal RNA and hydroxymethylbilane synthase (HMBS) as the most stable reference genes, while GAPDH and TFRC were the least stable ones. Peptidylprolyl isomerase A [PIPA (cyclophilin A)], ribosomal protein, large, P0 (36-B4), beta-2-microglobulin (B2M), α1-tubulin, hypoxanthine-guanine phosphoribosyltransferase (HPRT) and β-actin showed relatively stable expression levels. The choice of reference genes with various expression stabilities exerted a profound influence on the expression profiles of 2 target genes, peroxisome proliferator-activated receptor (PPAR)γ2 and C/EBPα. In addition, western blot analysis revealed that the increased protein expression of GAPDH was markedly inhibited by berberine during adipocyte differentiation. This study highlights the importance of selecting suitable reference genes for qRT-PCR studies of gene expression during the process of adipogenesis.

Recent studies suggested that the ovarian cancers with negative excision repair cross-complementation group 1 enzyme (ERCC1) expression have a better response to platinum-based chemotherapy than those with positive ERCC1 expression. The objective of this study was to evaluate whether ERCC1 expression is associated with response to platinum-based chemotherapy in ovarian cancers. MEDLINE, PubMed, Web of Science and CNKI databases were used for searching studies relating to ERCC1 protein expression and response to platinum-based chemotherapy in ovarian cancers. Statistical analysis was based on the method for a fixed effects meta-analysis. Pooled odds ratios (ORs) with 95% confidence intervals for ERCC1 protein expression and response to platinumbased chemotherapy were generated. Publication bias was investigated with Begg’s test. Five studies involving 306 patients with ovarian cancer were included. Compared to patients with positive ERCC1 expression, those with negative ERCC1 expression had a better response to platinum-based chemotherapy. The pooled OR was 5.264 (95% CI: 2.928 – 9.464, P < 0.001) and publication bias was not found (P = 0.904). The result was similar in both in Asians and Caucasians (P < 0.001 and P = 0.028, respectively). ERCC1 protein expression status is significantly associated with response to platinum-based chemotherapy in ovarian cancers.

Mammalian mesenchymal stem cells (MSCs) have been shown to be strongly immunosuppressive in both animal disease models and human clinical trials. We have reported that the key molecule mediating immunosuppression by MSCs is species dependent: indoleamine 2,3-dioxygenase (IDO) in human and inducible nitric oxide synthase (iNOS) in mouse. In the present study, we isolated MSCs from several mammalian species, each of a different genus, and investigated the involvement of IDO and iNOS during MSC-mediated immunosuppression. The characterization of MSCs from different species was by adherence to tissue culture plastic, morphology, specific marker expression, and differentiation potential. On the basis of the inducibility of IDO and iNOS by inflammatory cytokines in MSCs, the tested mammalian species fall into two distinct groups: IDO utilizers and iNOS utilizers. MSCs from monkey, pig, and human employ IDO to suppress immune responses, whereas MSCs from mouse, rat, rabbit, and hamster utilize iNOS. Interestingly, based on the limited number of species tested, the iNOS-utilizing species all belong to the phylogenetic clade, Glires. Although the evolutionary significance of this divergence is not known, we believe that this study provides critical guidance for choosing appropriate animal models for preclinical studies of MSCs.

Previous research has shown that people can implicitly acquire mappings between word forms and literal meanings (Williams, 2004, 2005). We argue, from the metaphor-representation and embodiment perspectives, that people can unconsciously establish mappings between word forms and not only literal but also metaphorical meanings. Using Williams' (2005) paradigm, we found that transfer of form-meaning connections from a concrete domain (space) to an abstract domain (power) was achieved in a metaphor-consistent way without awareness. Our results support the view that unconscious knowledge can be flexibly deployed in an abstract way not previously explored in the implicit learning literature.

In this paper, we show that on the weighted Bergman space of the unit disk the essential norm of a noncompact Hankel operator equals its distance to the set of compact Hankel operators and is realized by infinitely many compact Hankel operators, which is analogous to the theorem of Axler, Berg, Jewell and Shields on the Hardy space in Axler et al. (Ann Math 109:601–612, 1979); moreover, the distance is realized by infinitely many compact Hankel operators with symbols continuous on the closure of the unit disk and vanishing on the unit circle.

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Aims: To determine whether circulating multiple miRNAs can be used as novel biomarkers for the diagnosis in breast cancer, we performed a systematic review and meta-analysis. Materials & methods: After searching the databases of PubMed, EMBASE and Web of Science, we used the bivariate meta-analysis model to summarize the diagnostic indices and plot the summary receiver operator characteristic curve. Results: The summary estimates revealed that the pooled sensitivity was 88% (95% CI: 82–93%); specificity was 84% (95% CI: 74–91%); positive likelihood ratio was 4.69 (95% CI: 2.93–7.51); negative likelihood ratio was 0.15 (95% CI: 0.09–0.25); diagnostic odds ratio was 38.21 (95% CI: 13.41–108.85); and the area under the curve was 0.93 (95% CI: 0.90–0.95). Conclusion: These results suggested that circulating multiple miRNAs might serve as novel biomarkers for breast cancer, with a relatively high level of accuracy.

The cellular and molecular mechanisms of glucose-stimulated β-cell proliferation are poorly understood. Recently, secreted frizzled-related protein 5 (encoded by Sfrp5; a Wnt signaling inhibitor) has been demonstrated to be involved in β-cell proliferation in obesity. A previous study demonstrated that glucose enhanced Wnt signaling to promote cell proliferation. We hypothesized that inhibition of SFRP5 contributes to glucose-stimulated β-cell proliferation. In this study, we found that the Sfrp5 level was significantly reduced in high glucose-treated INS-1 cells, primary rat β-cells, and islets isolated from glucose-infused rats. Overexpression of SFRP5 diminished glucose-stimulated proliferation in both INS-1 cells and primary β-cells, with a concomitant inhibition of the Wnt signaling pathway and decreased cyclin D2 expression. In addition, we showed that glucose-induced Sfrp5 suppression was modulated by the PI3K/AKT pathway. Therefore, we conclude that glucose inhibits Sfrp5 expression via the PI3K/AKT pathway and hence promotes rat pancreatic β-cell proliferation.

The purposes of the present study were twofold. First, we sought to establish whether tonal symmetry produces processing fluency. Second, we sought to explore whether symmetry and chunk strength express themselves differently in fluency, as an indication of different mechanisms being involved for sub- and supra-finite state processing. Across two experiments, participants were asked to listen to and memorize artificial poetry showing a mirror symmetry (an inversion, i.e., a type of cross serial dependency); after this training phase, people completed a four-choice RT task in which they were presented with new artificial poetry. Participants were required to identify the stimulus displayed. We found that symmetry sped up responding to the second half of strings, indicating a fluency effect. Furthermore, there was a dissociation between fluency effects arising from symmetry vs. chunk strength, with stronger fluency effects for symmetry rather than chunks in the second half of strings. Taken together, we conjecture a divide between finite state and supra-finite state mechanisms in learning grammatical sequences.

Long non-coding RNAs (lncRNAs) have been demonstrated to regulate metabolic tissue development and function, including adipogenesis, hepatic lipid metabolism, islet function and energy balance. However, the role of lncRNAs in gluconeogenesis remains completely unknown. Metformin reduces glucose output mainly via the inhibition of gluconeogenesis. In the present study, the lncRNA expression profile of primary mouse hepatocytes exposed to cyclic adenosine monophosphate (cAMP), a gluconeogenic stimulus, with or without metformin was analyzed by microarray. Among the 22,016 lncRNAs that were identified, 456 were upregulated and 409 were downregulated by cAMP (fold-change ≥2.0). Furthermore, the cAMP-induced upregulation of 189 lncRNAs and downregulation of 167 lncRNAs was attenuated by metformin. The expression levels of eight lncRNAs were validated by reverse transcription-quantitative polymerase chain reaction, and the results were consistent with those of the microarray analysis. Among them, two lncRNAs NR_027710 and ENSMUST00000138573, were identified to have an association with two protein coding genes, namely peroxisome proliferator-activated receptor-γ coactivator-1α, a critical transcriptional coactivator in gluconeogenesis, and G protein-coupled receptor 155, respectively. The two protein coding genes exhibited similar expression patterns to their associated lncRNAs. The findings of the present study suggest that lncRNAs are potentially involved in the regulation of gluconeogenesis.

Background Like adults, children need to allocate study time and endeavour optimally in order to enhance learning effectiveness. Aims The aim of this study was to investigate the development of shifting from habitual to agenda-based processes on study decisions. Sample The participants were 309 children in the second, fourth, and sixth grades. Methods We adopted the research paradigm proposed by Ariel and Dunlosky (2013, Mem. Cognit., 41, 416). In Experiment 1, the students selected items to study either with or without time constraint. In Experiment 2, the students were instructed to select all three items or one item to study per trial. Results The results of Experiment 1 showed that for sixth graders, the likelihood of selecting high-value items under the restricted-study-time condition was higher than that under the restricted-total-time condition; second and fourth graders failed to construct an agenda of prioritizing high-reward items for study in the restricted-study-time condition. In Experiment 2, when students were instructed to select one item to study per trial, high-value items were prioritized over items on the left of the array for sixth graders; on the contrary, second and fourth graders seemed to choose item for study arbitrary, although they tend to choose high-value items compared with their choice pattern in no-choice-limit condition. Conclusions The results indicate that children can shift towards agenda-based process when habitual responding cannot maximize reward, and there is an age-related improvement in shifting between grade 4 and grade 6.

This meta-analysis aimed to evaluate whether an association exists between the ERCC1 rs11615 (C>T) polymorphism and patient response to platinum-based chemotherapy and radiation-based chemotherapy. Publications were selected from PubMed and MEDLINE. A meta-analysis was conducted to determine the association between genetic polymorphisms and response to platinum-based chemotherapy and radiation-based chemotherapy by checking the odds ratios (ORs) and 95 % confidence intervals (CIs). In our overall analysis, the ERCC1 rs11615 (C>T) polymorphism was not associated with response to platinum-based chemotherapy in five comparison models. In the subgroup analyses by ethnicity, the ERCC1 rs11615 (C>T) polymorphism was shown to be significantly associated with objective response in Caucasian patients treated with platinum-based chemotherapy in the recessive model (TT vs. CT/CC: OR 0.696, 95 % CI 0.508–0.954, heterogeneity = 0.330), but the association was not observed in the Asian population. The C allele was significantly associated with better response to radiochemotherapy in the recessive model comparison (TT vs. CC/CT: OR 0.724, 95 % CI 0.585–0.869, heterogeneity = 0.008). Subgroup analysis by cancer type revealed that the C allele of ERCC1 rs11615 predicted a better response in esophageal cancers in two comparison models (T vs. C: OR 0.756, 95 % CI 0.648–0.880, heterogeneity = 0.653; TT vs. TC/CC: OR 0.457, 95 % CI 0.306–0.684, heterogeneity = 0.723). Stratified analysis by ethnicity showed a better response in Caucasians in allelic comparison model (T vs. C: OR 0.895, 95 % CI 0.819–0.977, heterogeneity = 0.095). Together, our results suggest that the ERCC1 rs11615 (C>T) polymorphism was associated with therapeutic response in Caucasian patients and C allele of ERCC1 rs11615 could represent a genetic molecular marker to predict better patient response to radiochemotherapy in recessive model. However, larger prospective randomized trials will be required.

Osteoblasts and adipocytes are derived from a common precursor, mesenchymal stem cells (MSCs). Alterations in the normal fate of differentiating MSCs are involved in the development of obesity and osteoporosis. Here, we report that viable motheaten (me(v)) mice, which are deficient in the SH2-domain-containing phosphatase-1 (SHP1), develop osteoporosis spontaneously. Consistently, MSCs from me(v)/me(v) mice exhibit significantly reduced osteogenic potential and greatly increased adipogenic potential. When MSCs were transplanted into nude mice, SHP1-deficient MSCs resulted in diminished bone formation compared with wild-type MSCs. SHP1 was found to bind to GSK3β and suppress its kinase activity by dephosphorylating pY216, thus resulting in β-catenin stabilization. Mice, in which SHP1 was deleted in MSCs using SHP1(fl/fl)Dermo1-cre, displayed significantly decreased bone mass and increased adipose tissue. Taken together, these results suggest a possible role for SHP1 in controlling tissue homeostasis through modulation of MSC differentiation via Wnt signaling regulation.

Obesity-associated inflammation is accompanied by the accumulation of adipose tissue macrophages (ATMs), which is believed to predispose obese individuals to insulin resistance. CD11b (integrin αM) is highly expressed on monocytes and macrophages and is critical for their migration and function. We found here that high-fat diet–induced insulin resistance was significantly reduced in CD11b-deficient mice. Interestingly, the recruitment of monocytes to adipose tissue is impaired when CD11b is deficient, although the cellularity of ATMs in CD11b-deficient mice is higher than that in wild-type mice. We further found that the increase in ATMs is caused mainly by their vigorous proliferation in the absence of CD11b. Moreover, the proliferation and alternative activation of ATMs are regulated by the IL-4/STAT6 axis, which is inhibited by CD11b through the activity of phosphatase SHP-1. Thus, CD11b plays a critical role in obesity-induced insulin resistance by limiting the proliferation and alternative activation of ATMs.

The preservation of pancreatic β-cell function is a key point in the treatment of type 2 diabetes mellitus. There is substantial evidence demonstrating that heat-shock protein 90 (Hsp90) is needed for the stabilization and correct folding of client proteins and plays important roles in various biological processes. Here, we revealed the important role of Hsp90 in β-cell function. Islets from male Sprague–Dawley rats were isolated to be used for further RT-PCR, Western blot, and insulin secretion test ex vivo in response to different stimuli. Our results revealed that Hsp90 expression was significantly decreased in isolated rat islets exposed to high glucose, which was involved in glucokinase activation and glucose metabolism, not calcium signaling. Two kinds of Hsp90 inhibitors 17-DMAG and CCT018159 markedly enhanced glucose-stimulated insulin secretion from rat islets, along with increased expressions of genes closely related to β-cell function. These data indicate that Hsp90 may be involved in high glucose-induced islet function adaptation.

As a major ecosystem type, wetland provides invaluable ecological services. Environmental pollution, especially pesticides pollution should be paid more attention to keep wetlands healthy. Based on the risk quotient method, coupled with a probabilistic risk assessment model, this paper proposed a methodology suitable for ecological risk assessment of pesticide residues for wetland ecosystems. As an important industrializing and ecologically vulnerable area in China, the Taihu Lake wetland was chosen for the case study. The risks of eight pesticides in Taihu Lake wetland were assessed, as single substances and in mixtures. The assessment indicates that risks of the representative species are not significant. In general, the herbicide is found to be more toxic for algae, whereas insecticides pose more risks to zooplankton, insect and fish. For each pesticide in the wetland, the ecological risk it poses is acceptable. But the combined ecological risk posed by mixture can harm more than 10% of species of the wetland ecosystem, mainly dominated by dichlorvos, dimethoate and malathion contributions. These results imply that pesticide residues have been posing pressures on the ecosystem of the Taihu Lake wetland. It is recommended that proper countermeasures should be implemented to reduce the risks.

This paper investigated preparation process of briquette by using starch and bentonite as composite binder. It also studied the impact of pulverized coal particle size, coking particle size, compacting pressures, moisture content on the strength of briquette and form coke. The result showed that coking coal particle size was the main influence factor. And the optimum conditions of molding process were as follows: low rank pulverized coal particle size was less than 0.63mm, coking coal particle size was less than 0.28mm, compacting pressure was 60 kN, molding moisture content was 12%. Under the optimal conditions, compressive strength of briquette and form coke was 3470 N/ball and 2910 N/ball, respectively.

Pulmonary fibroblasts regulate extracellular matrix production and degradation and are critical in maintenance of lung structure, function, and repair, but they also play a central role in lung fibrosis. cAMP-elevating agents inhibit cytokine- and growth factor-stimulated myofibroblast differentiation and collagen synthesis in pulmonary fibroblasts. In the present study, we overexpressed adenylyl cyclase 6 (AC6) in pulmonary fibroblasts and measured cAMP production and collagen synthesis. AC6 overexpression enhanced cAMP production and the inhibition of collagen synthesis mediated by isoproterenol and beraprost, but not the responses to butaprost or PGE2. To examine if increased AC6 expression would impact the development of fibrosis in an animal model, we generated transgenic mice that overexpress AC6 under a fibroblast-specific promoter, FTS1. Lung fibrosis was induced in FTS1-AC6+/−mice and littermate controls by intratracheal instillation of saline or bleomycin. Wild-type mice treated with bleomycin showed extensive peribronchial and interstitial fibrosis and collagen deposition. By contrast, FTS1-AC6+/−mice displayed decreased fibrotic development, lymphocyte infiltration (as determined by pathological scoring), and lung collagen content. Thus, AC6 overexpression inhibits fibrogenesis in the lung by reducing pulmonary fibroblast-mediated collagen synthesis and myofibroblast differentiation. Because AC6 overexpression does not lead to enhanced basal or PGE2-stimulated levels of cAMP, we conclude that endogenous catecholamines or prostacyclin is produced during bleomycin-induced lung fibrosis and that these signals have antifibrotic potential.

This paper reports a novel colorimetric sensor for tryptophan based on 4,4-bipyridine-functionalized silver nanoparticles (4-DPD-Ag NPs) which were characterized by IR spectroscopy, ultraviolet–visible spectroscopy (UV–vis), and transmission electron microscopy (TEM). The newly synthesized 4-DPD-Ag NPs are yellow in color due to the intense surface plasmon absorption band centered at 390 nm. In the presence of tryptophan, the yellow 4-DPD-Ag NPs solution turns to red accompanying a dramatic surface plasmon absorption band centered at 556 nm. However, the sensitivity of 4-DPD-Ag NPs towards other neutral amino acids, including leucine, threonine, valine, phenylalanine, tyrosine, proline, serine, pyroglutamic acid and cysteine can be negligible. This highly selective sensor allows a direct and rapid quantitative assay of tryptophan with a colorimetric limited detection concentration of 2 × 10−5 M. The possible underlying mechanism is discussed.

Algorithms based on timed Petri net are competitive for solving the problem of assembly sequence planning (ASP). In order to alleviate the state-space explosion problem which is caused by the Petri net-based representation of assembly sequences and to improve the efficiency of planning algorithms, an approach based on ordinary binary decision diagrams (OBDDs) is presented in this paper. On the one hand, all the timed transitions in Petri nets are substituted by some technically designed timed transition structures; on the other hand, Petri nets used in algorithms of assembly sequence planning are represented symbolically as OBDDs. As a result, a novel assembly sequence planning algorithm based on symbolic OBDDs is presented. With the help of OBDDs, both the marking vectors and the states of Petri nets are formulated more compactly; at the same time, the searching processes can be manipulated implicitly. Therefore, compared with original algorithms, both the time performance and the space performance are improved.

A questionnaire survey of residents’ risk perceptions related to Taiwan nuclear power plant in China was carried out to explore the determining factors that affect individual risk perception. This study proposed to pursue a more comprehensive understanding of factors that affected individual risk perception to nuclear power plants. Covariance structure analysis was conducted using risk perceptions of nuclear power as dependent variable and including interest and knowledge levels of nuclear power, acceptability, benefit perception, trust in nuclear power operation, and trust in government as independent variables. The use of the hypothesis of Elaboration likelihood model (ELM) was also proposed. The results showed that persons with higher levels of interest and knowledge of nuclear power had their own perceptions of risk closely associated with acceptability and potential benefits of nuclear power. In contrast, persons with no interest in and knowledge of nuclear power would have risk perceptions related to their trust in nuclear operation and the government, which partially supported the ELM hypothesis. All these results indicated that the government in China plays an important role in rational risk perceptions, and well-designed communication of risks will help the public to be involved in risk management and improve people’s rational acceptance of risk.

The 6H and 6M Ba 1− x Sr x RuO 3 at x ⩽0.6 with the normal and distorted hexagonal BaTiO 3 structures were synthesized by using high-pressure and high-temperature method. It is found that the unit cell volume deviates from Vegard's law between 0.3 and 0.4 for the solid solutions due to the increasing distortion degree of crystal structure. With the increasing x , the electrical resistivity at the same temperature is increasing. With the substitution of Sr for Ba ion, the 6H BaRuO 3 transforms to a Fermi-liquid metal at x =0.25 from the primal non-Fermi-liquid metal, and then becomes a semiconductor at low temperature when x is larger than 0.4.

Activated carbon was treated at 5 GPa up to 1600 °C, and the structural evolution in the graphitization process was investigated. The graphitization temperature is equal to 1200 °C at 5 GPa, reflected by X-ray diffraction (XRD) patterns. Honeycomb-like structures in micron scale come into being in the high-pressure sintering temperature range of 1000−1100 °C and slice-like structures appear after graphitization. The existence of D and D’ lines in the Raman spectra for the graphitized-activated carbon indicates that there are still some disordered structures. The continuous occurrence of variable-range hopping, the approximately linear ρ–T relationship, and semimetal conduction mechanism accords with the graphitization process.

The in situ high-pressure measurements of electrical resistivity versus temperature for weak ferromagnetic BaIrO(3) have been performed, using a Cu-Be piston-cylinder-type apparatus up to 1.0 GPa at 80-300 K. The electrical resistivity is increasing with pressure. The pressure derivative of Curie temperature partial derivative T(c)/partial derivative P is equal to -6.1(2) K/GPa, and the relative pressure dependence partial derivative In T(c)/partial derivative P is equal to -3.4(1)%/GPa, which indicates that BaIrO(3) is a weak itinerant ferromagnet. (C) 2008 Elsevier Ltd. All rights reserved.

The crystal structure stability as well as electric conductance of (Sr/Ca)2CuO2Cl2 compound with K2NiF4 structure was investigated up to 31 GPa using diamond anvil technique. It seems that (Sr/Ca)2CuO2Cl2 is quite stable under pressure but with obvious anisotropic compressibility. The equation of state (EOS) obtained shows relative large bulk modulus.

Berberine, a hypoglycemic agent, has recently been shown to activate AMP-activated protein kinase (AMPK) contributing to its beneficial metabolic effects in peripheral tissues. However, whether berberine exerts a regulatory effect on β-cells via AMPK or other signaling pathways and counteracts glucolipotoxicity remains uncertain. In the present study, the impact of berberine on β-cell function was investigated in vivo and in vitro. In high-fat-fed rats, berberine treatment for 6 wk significantly decreased plasma glucose and insulin levels before and after an oral glucose challenge along with the reduction of body weight and improvement of blood lipid profile. In accordance with the in vivo results, berberine acutely decreased glucose-stimulated insulin secretion (GSIS) and palmitate-potentiated insulin secretion in MIN6 cells and rat islets. However, pretreated with berberine for 24 h augmented the response of MIN6 cells and rat islets to glucose and attenuated the glucolipotoxicity. Berberine acutely increased AMPK activity in MIN6 cells. However, compound C, an AMPK inhibitor, completely reversed troglitazone-suppressed GSIS, not berberine-suppressed GSIS. Otherwise, berberine decreased cAMP-raising agent-potentiated insulin secretion in MIN6 cells and rat islets. These results suggest that the activation of AMPK is required for troglitazone-suppressed GSIS, whereas cAMP signaling pathway contributes, at least in part, to the regulatory effect of berberine on insulin secretion.

Visfatin was recently identified as an adipocytokine and has insulin mimetic properties, but its role in adolescents remains largely unknown. In this study, we examined the impact of adolescent obesity on circulating visfatin levels and the relationship between visfatin and anthropometric indices, insulin sensitivity, and blood lipids in Chinese adolescents (11-18 years). Serum visfatin, adiponectin, leptin, and blood lipids were measured in 76 non-obese and 72 obese adolescents. The medians of serum visfatin levels were significantly higher in obese subjects of 34.68ng/ml than in non-obese subjects of 28.67ng/ml (P=0.002). There were no significant correlations in the non-obese group between the serum visfatin concentration and the anthropometric indices or the lipid parameters. However, visfatin levels were negatively correlated with age, early insulin secretion index (EISI), Tanner stage, and positively correlated with HDL-c in the obese adolescents. These relationships, except that for EISI and Tanner stage, remained significant (P0.05) after adjusting for age, gender, and body mass index. Moreover, unlike adiponectin and leptin, visfatin concentration did not correlate with testosterone in non-obese and obese boys. In conclusion, visfatin levels may decrease with age and be related to the HDL metabolism in obese adolescents.

Changes in AMP-activated protein kinase (AMPK) activity contribute to the regulation of insulin secretion. Troglitazone has been shown to lower serum insulin levels and protect beta cell function. The aim of the present study was to examine the effects of troglitazone on AMPK activity and insulin secretion in beta cells. Isolated rat islets and MIN6 cells were treated for a short (1 h) or a long time (20 h) with troglitazone. One-hour troglitazone treatment activated AMPK and inhibited both glucose-stimulated insulin secretion (GSIS) and the response of insulin secretion to combined stimuli of glucose and palmitate. Long (20 h) treatment with troglitazone caused a sustained phosphorylation of AMPK and acetyl-CoA carboxylase, and increased GSIS after withdrawal of the drug. This study provided evidence that troglitazone activated AMPK in beta cells. In addition to the insulin-sensitizing effects in peripheral tissues, troglitazone also directly inhibits insulin hypersecretion by the elevated glucose and fatty acids, and thus protects beta cells from glucolipotoxicity.

AMP-activated protein kinase (AMPK) is an energy sensor that regulates cellular metabolism. Changes in AMPK activity contribute to the regulation of insulin secretion. Epidemiological evidence links the ingestion of saturated fatty acid with hyperinsulinemia. The aim of the present study was to examine the effects of palmitate on beta cell AMPK activity and insulin secretion. Isolated rat islets and MIN6 beta cells were treated acutely (5-60 min) or chronically (24 h) with palmitate. Insulin secretion, AMPK and acetyl CoA carboxylase phosphorylation were assessed. The acute effects of palmitate included AMPK activation and augmentation in insulin secretion. Activation of AMPK by 24h pretreatment with palmitate suppressed glucose-stimulated insulin secretion, but not the response of insulin secretion to combined stimuli of glucose and palmitate. This study demonstrated that palmitate availability affected beta cell AMPK activity. In beta cells, an increase in AMPK activity may be required for fatty acid-induced fatty acid oxidation and prevention of lipotoxicity.

Position-based cryptography has attracted lots of researchers' attentions. In mobile Internet, there are lots of position based security applications. For the first time, one new conception, position-based proxy signcryption is proposed. Based on a secure positioning protocol, one model of position-based proxy signcryption is proposed. In the model, positioning protocol is tightly bound to proxy signcryption, not loosely. Further, we propose one concrete position-based proxy signcryption scheme, its correctness is proved, and its security is also analyzed. As far as we know, it is the first position-based proxy signcryption scheme.

Beta cell replication is the major component for maintenance of beta cell mass in adult rodents; however, little is known about what is the earliest signals that initiate rodent beta cell proliferation. The mTORC1 pathway integrates signals from growth factors and nutrients and regulates cell growth and survival. Here, we used normoglycemic 60 % partial-pancreatectomy (60 % Px) mouse model to determine whether mTORC1 pathway was required for compensatory beta cell proliferation. C57BL/6 J male mice were subjected to 60 % Px or sham operation, and subsequently treated with either rapamycin or vehicle for 7 days. Metabolic profile, pancreatic beta cell mass, and proliferation were examined, and expression levels of cell cycle regulators were determined. Beta cell proliferation was increased by 2.5-fold, and mTORC1 signaling was activated in islets post-Px. Rapamycin treatment impaired glucose tolerance and glucose stimulating insulin secretion in 60 % Px mice, but did not affect their insulin sensitivity in peripheral tissue. Rapamycin inhibited mTORC1 activity in beta cells, suppressed compensatory beta cell proliferation and growth, and reduced beta cell mass and insulin content in 60 % Px mice. Px caused an increase of the cyclin D2 at protein level and promoted cyclin D2 nuclear localization in an mTOR-dependent manner. Disrupting mTORC1 signaling suppressed cell proliferation and simultaneously diminished cyclin D2 protein abundance in RINm5F cells. Our data demonstrated that mTORC1 plays an essential role in beta cell adaption to significant beta cell mass loss in 60 % Px model and in early compensatory beta cell proliferation via cyclin D2 pathway.

Position-based cryptography has attracted many researchers’ attention. In mobile Internet, there are lots of position-based security applications. In the paper, one new conception, positioning-protocol-based digital signature is proposed. Based on a secure positioning protocol, one model of positioning-protocol-based digital signature is proposed. In the model, the positioning protocol is bound to digital signature tightly, not loosely. Further, we propose one concrete positioning-protocol-based digital signature scheme and its correctness is proved.

Data insufficiency has become the primary factor affecting research on income disparity in China. To resolve this issue, this paper explores Chinese income distribution and income inequality using distribution functions. First, it examines 20 sets of grouped data on family income between 2005 and 2012 by theChina Yearbook of Household Surveys, 2013,and compares the fitting effects of eight distribution functions. The results show that the generalized beta distribution of the second kind has a high fitting to the income distribution of urban and rural residents in China. Next, these results are used to calculate the Chinese Gini ratio, which is then compared with the findings of relevant studies. Finally, this paper discusses the influence of urbanization on income inequality in China and suggests that accelerating urbanization can play an important role in narrowing the income gap of Chinese residents.

Position-based cryptography has attracted lots of researchers’ attentions. In mobile Internet, there are many position-based security applications. For the first time, one new conception, multi-proxy multi-signature (MPMS) binding positioning protocol is proposed. Based on one secure positioning protocol, one model of MPMS binding positioning protocol is proposed. In the model, positioning protocol is bound to MPMS tightly, not loosely. Further, we propose one scheme of MPMS binding positioning protocol. As far as we know, it is the first scheme of MPMS binding positioning protocol.

Fe-substituted materials Sr 2 Fe 1+ x Mo 1− x O 6− δ ( x = 0, 0.1, 0.2, 0.3, 0.4) were synthesized by a modified polymer-network gel method at a relatively low temperature. The structural stability and electrical properties of Sr 2 FeMoO 6 and Sr 2 Fe 1.4 Mo 0.6 O 6− δ have been studied using energy dispersive X-ray diffraction with synchrotron radiation and resistance and capacitance measurements, respectively. The results show that the crystal structure of Sr 2 Fe 1.4 Mo 0.6 O 6− δ is as stable as Sr 2 FeMoO 6 at high pressure and more compressible than Sr 2 FeMoO 6 . On the basis of the measurements of resistance and capacitance versus pressure, it is considered that they all undergo an electronic structure transition under high pressure.

The series of the Sr2FeMo1-xNbxO6 compounds have been synthesized throughout the range of 0 less than or equal to x less than or equal to 1 using conventional solid-state reaction method. The compounds show a tetragonal structure in the range of 0 less than or equal to x less than or equal to 0.4 while showing an orthorhombic structure in the range of 0.5 less than or equal to x less than or equal to 1. Magnetic and electrical properties of the compounds have been studied in order to investigate the effect of the substitution of non-magnetic Nb5+ ion for Mo5+ (or Mo6+) ion in the double perovskite compound. The magnetization (M) values are found to decrease slowly with increasing x in all compounds with 0 less than or equal to x less than or equal to 0.75 due to less correlation among the magnetic ions induced by the non-magnetic Nb5+ ions. The measurements of magnetic susceptibilities at zero-field-cooled and field-cooled conditions show that a transition from a ferromagnetic (FM) to a ferro-cluster glass state gradually transforms from a paramagnetic (PM) to a spin-glass state with increasing Nb5+ content. With increasing x, the conductivity decreases. Meanwhile, the compounds lose the ferromagnetic component. The compounds have good conductivity from 10(-3) to 10 Omega cm with x in the range of 0 less than or equal to x less than or equal to 0.3, though they show insulator behavior. While those with x in the range of 0.6 less than or equal to x less than or equal to 0.75 show poor transport property. All samples with x greater than or equal to 0.25 show large negative magnetoresistances (MRs), similar to that observed in Sr2FeMoO6. (C) 2004 Elsevier B.V. All rights reserved.

The resistance-pressure (R-P) and capacitance-pressure (C-P) relationships for the compounds Sr2FeMoxNb1-xO6 (x = 0, 0.3) have been studied in the pressure range of 0-20 GPa using a diamond anvil cell at room temperature. According to the analysis of energy dispersive x-ray diffraction with synchrotron radiation, in the range of experimental precision, the changes in R-P and C-P for Sr2FeNbO6 and Sr2FeMo0.3Nb0.7O6 at about 7.5 and 2.8 GPa, respectively, are considered as electronic transitions caused by high pressure.

Using pulse echo overlap measurement, the elastic behavior of amorphous carbon has been studied at ambient and low temperatures. The smaller ratio BIG of the bulk modulus to shear modulus and smaller Poisson's ratio sigma at room temperature indicate that there is an intrinsic stiffening of transverse acoustic phonons in the amorphous carbon. The acoustic velocity and attenuation for longitudinal modes have been measured between 2.1 and 300 K at three frequencies of 7, 21 and 35 MHz, respectively. Their frequency and temperature dependence are observed. The elastic constant C-11 increases with decreasing temperature and show enhanced stiffening at low temperatures. In the 130-220 K region, the abnormal change and effect of longitudinal velocity and attenuation with temperature and frequency, and a phase transition associated with structure relaxations are discussed. (C) 2003 Elsevier Science Ltd. All rights reserved.

The longitudinal and shear velocities, and their pressure dependences, for various bulk amorphous materials, including bulk metallic glasses and non-metallic glasses, have been measured by the ultrasonic pulse echo overlap method under hydrostatic pressure (maximum: 2 GPa) or uniaxial compression in ambient conditions. The second- or third-order elastic constants and the long-wavelength acoustic mode Gruneisen parameter are calculated. The results reveal that all metallic glasses have positive pressure dependences of both the longitudinal and shear velocities, while for most non-metallic glasses both the longitudinal and shear velocities decrease with increasing pressure. Thus, the Gruneisen parameters evaluated for the mean mode and shear mode for metallic glasses and non-metallic glasses have opposite signs. This indicates that the influences of the short-range-order structure and bonding, correlating closely with the atomic configurations in the various amorphous materials, play an important role in the properties determined by vibrational anharmonicity. The negative and positive Gruneisen parameters exhibit mode softening and stiffness under high pressure, respectively. The results also clearly demonstrate that the Gruneisen parameter is affected by the pressure derivative of the shear modulus, especially for non-metallic glasses.