251 research outputs found

    What predicts medical lethality of suicide attempts in Asian youths?

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    This study explores youth suicide attempts in Singapore using multiple databases of comprehensive archivalrecords. Three years of medical records related to suicide attempters (N = 666) who were admitted to theemergency department of a large teaching hospital in Singapore were subjected to retrospective analysis.Compared to other age groups, a peak in suicide attempts (n = 207) was observed in youths aged between 15and 24 years old (76.3% females; 23.7% males, mean age = 19.30, SD = 2.89). The model using recognized riskand protective factors was significant in predicting medical lethality, and correctly classified 62.8% of highlethality cases. Only resolution of precipitant made a unique statistical significant contribution. Analysis wasseparately conducted for males and females. Implications of the findings are discussed

    Microbial fuel cells: a green and alternative source for bioenergy production

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    Microbial fuel cell (MFC) represents one of the green technologies for the production of bioenergy. MFCs using microalgae produce bioenergy by converting solar energy into electrical energy as a function of metabolic and anabolic pathways of the cells. In the MFCs with bacteria, bioenergy is generated as a result of the organic substrate oxidation. MFCs have received high attention from researchers in the last years due to the simplicity of the process, the absence in toxic by-products, and low requirements for the algae growth. Many studies have been conducted on MFC and investigated the factors affecting the MFC performance. In the current chapter, the performance of MFC in producing bioenergy as well as the factors which influence the efficacy of MFCs is discussed. It appears that the main factors affecting MFC’s performance include bacterial and algae species, pH, temperature, salinity, substrate, mechanism of electron transfer in an anodic chamber, electrodes materials, surface area, and electron acceptor in a cathodic chamber. These factors are becoming more influential and might lead to overproduction of bioenergy when they are optimized using response surface methodology (RSM)

    Numerical study on load-bearing capabilities of beam-like lattice structures with three different unit cells

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    The design and analysis of lattice structures manufactured using Additive Manufacturing (AM) technique is a new approach to create lightweight high-strength components. However, it is difficult for engineers to choose the proper unit cell for a certain function structure and loading case. In this paper, three beam-like lattice structures with triangular prism, square prism and hexagonal prism were designed, manufactured by SLM process using AlSi10Mg and tested. The mechanical performances of lattice structures with equal relative density, equal base area and height, and equal length for all unit cells were conducted by Finite Element Analysis (FEA). It was found that effective Young’s modulus is proportional to relative density, but with different affecting levels. When the lattice structures are designed with the same relative density or the same side lengths, the effective Young’s modulus of lattice structure with triangular prism exhibits the maximum value for both cases. When the lattice structures are designed with the same base areas for all unit cells, the effective Young’s modulus of lattice structures with square prism presents the maximum. FEA results also show that the maximum stress of lattice structures with triangular prisms in each comparison is at the lowest level and the stiffness-to-mass ratio remains at the maximum value, showing the overwhelming advantages in terms of mechanical strength. The excellent agreements between numerical results and experimental tests reveal the validity of FEA methods applied. The results in this work provide an explicit guideline to fabricate beam-like lattice structures with the best tensile and bending capabilities

    Emerging strengths in Asia Pacific bioinformatics

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    The 2008 annual conference of the Asia Pacific Bioinformatics Network (APBioNet), Asia's oldest bioinformatics organisation set up in 1998, was organized as the 7th International Conference on Bioinformatics (InCoB), jointly with the Bioinformatics and Systems Biology in Taiwan (BIT 2008) Conference, Oct. 20–23, 2008 at Taipei, Taiwan. Besides bringing together scientists from the field of bioinformatics in this region, InCoB is actively involving researchers from the area of systems biology, to facilitate greater synergy between these two groups. Marking the 10th Anniversary of APBioNet, this InCoB 2008 meeting followed on from a series of successful annual events in Bangkok (Thailand), Penang (Malaysia), Auckland (New Zealand), Busan (South Korea), New Delhi (India) and Hong Kong. Additionally, tutorials and the Workshop on Education in Bioinformatics and Computational Biology (WEBCB) immediately prior to the 20th Federation of Asian and Oceanian Biochemists and Molecular Biologists (FAOBMB) Taipei Conference provided ample opportunity for inducting mainstream biochemists and molecular biologists from the region into a greater level of awareness of the importance of bioinformatics in their craft. In this editorial, we provide a brief overview of the peer-reviewed manuscripts accepted for publication herein, grouped into thematic areas. As the regional research expertise in bioinformatics matures, the papers fall into thematic areas, illustrating the specific contributions made by APBioNet to global bioinformatics efforts

    Challenges in Whole Exome Sequencing: An Example from Hereditary Deafness

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    Whole exome sequencing provides unprecedented opportunities to identify causative DNA variants in rare Mendelian disorders. Finding the responsible mutation via traditional methods in families with hearing loss is difficult due to a high degree of genetic heterogeneity. In this study we combined autozygosity mapping and whole exome sequencing in a family with 3 affected children having nonsyndromic hearing loss born to consanguineous parents. Two novel missense homozygous variants, c.508C>A (p.H170N) in GIPC3 and c.1328C>T (p.T443M) in ZNF57, were identified in the same ∼6 Mb autozygous region on chromosome 19 in affected members of the family. Both variants co-segregated with the phenotype and were absent in 335 ethnicity-matched controls. Biallelic GIPC3 mutations have recently been reported to cause autosomal recessive nonsyndromic sensorineural hearing loss. Thus we conclude that the hearing loss in the family described in this report is caused by a novel missense mutation in GIPC3. Identified variant in GIPC3 had a low read depth, which was initially filtered out during the analysis leaving ZNF57 as the only potential causative gene. This study highlights some of the challenges in the analyses of whole exome data in the bid to establish the true causative variant in Mendelian disease

    Accelerated Evolution of the Prdm9 Speciation Gene across Diverse Metazoan Taxa

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    The onset of prezygotic and postzygotic barriers to gene flow between populations is a hallmark of speciation. One of the earliest postzygotic isolating barriers to arise between incipient species is the sterility of the heterogametic sex in interspecies' hybrids. Four genes that underlie hybrid sterility have been identified in animals: Odysseus, JYalpha, and Overdrive in Drosophila and Prdm9 (Meisetz) in mice. Mouse Prdm9 encodes a protein with a KRAB motif, a histone methyltransferase domain and several zinc fingers. The difference of a single zinc finger distinguishes Prdm9 alleles that cause hybrid sterility from those that do not. We find that concerted evolution and positive selection have rapidly altered the number and sequence of Prdm9 zinc fingers across 13 rodent genomes. The patterns of positive selection in Prdm9 zinc fingers imply that rapid evolution has acted on the interface between the Prdm9 protein and the DNA sequences to which it binds. Similar patterns are apparent for Prdm9 zinc fingers for diverse metazoans, including primates. Indeed, allelic variation at the DNA–binding positions of human PRDM9 zinc fingers show significant association with decreased risk of infertility. Prdm9 thus plays a role in determining male sterility both between species (mouse) and within species (human). The recurrent episodes of positive selection acting on Prdm9 suggest that the DNA sequences to which it binds must also be evolving rapidly. Our findings do not identify the nature of the underlying DNA sequences, but argue against the proposed role of Prdm9 as an essential transcription factor in mouse meiosis. We propose a hypothetical model in which incompatibilities between Prdm9-binding specificity and satellite DNAs provide the molecular basis for Prdm9-mediated hybrid sterility. We suggest that Prdm9 should be investigated as a candidate gene in other instances of hybrid sterility in metazoans

    Gender Difference of Alanine Aminotransferase Elevation May Be Associated with Higher Hemoglobin Levels among Male Adolescents

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    BACKGROUND: To explore the gender difference of ALT elevation and its association with high hemoglobin levels. METHODS: A cross-sectional study of 3547 adolescents (2005 females, mean age of 16.5?.3 years) who were negative for hepatitis B surface antigen received health checkups in 2006. Body mass index (BMI), levels of hemoglobin, ALT and cholesterol were measured. ALT >42 U/L was defined as elevated ALT. Elevated ALT levels were detected in 112 of the 3547 participants (3.3%), more prevalent in males than in females (5.4% vs. 1.4%, p<0.001). Hemoglobin levels had a significant linear correlation with ALT levels in both genders. Abnormal ALT started to occur if hemoglobin >11 g/dl in females or >13.5 g/dl in males, but the cumulative cases of elevated ALT increased more quickly in males. Proportion of elevated ALT increased as either the BMI or hemoglobin level rise, more apparent in male adolescents. Logistic regression modeling showed odds ratio (95% confidence interval) were 24.7 (15.0-40.6) for BMI ≥27 kg/m(2); 5.5 (2.9-10.4) for BMI 24-27 kg/m(2); 2.7 (1.3-5.5) for Q5 (top 20th percentile) hemoglobin level; and 2.6 (1.6-4.1) for male gender. Further separately fitting the logistic models for two genders, the significance of Q5 hemoglobin level only appeared in the males. CONCLUSIONS: High hemoglobin level is a significant risk factor of ALT elevation after control hepatitis B, obesity and gender. Males have greater risk of abnormal liver function which may be associated with higher hemoglobin levels

    Human Fetal Liver Stromal Cells That Overexpress bFGF Support Growth and Maintenance of Human Embryonic Stem Cells

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    In guiding hES cell technology toward the clinic, one key issue to be addressed is to culture and maintain hES cells much more safely and economically in large scale. In order to avoid using mouse embryonic fibroblasts (MEFs) we isolated human fetal liver stromal cells (hFLSCs) from 14 weeks human fetal liver as new human feeder cells. hFLSCs feeders could maintain hES cells for 15 passages (about 100 days). Basic fibroblast growth factor (bFGF) is known to play an important role in promoting self-renewal of human embryonic stem (hES) cells. So, we established transgenic hFLSCs that stably express bFGF by lentiviral vectors. These transgenic human feeder cells — bFGF-hFLSCs maintained the properties of H9 hES cells without supplementing with any exogenous growth factors. H9 hES cells culturing under these conditions maintained all hES cell features after prolonged culture, including the developmental potential to differentiate into representative tissues of all three embryonic germ layers, unlimited and undifferentiated proliferative ability, and maintenance of normal karyotype. Our results demonstrated that bFGF-hFLSCs feeder cells were central to establishing the signaling network among bFGF, insulin-like growth factor 2 (IGF-2), and transforming growth factor β (TGF-β), thereby providing the framework in which hES cells were instructed to self-renew or to differentiate. We also found that the conditioned medium of bFGF-hFLSCs could maintain the H9 hES cells under feeder-free conditions without supplementing with bFGF. Taken together, bFGF-hFLSCs had great potential as feeders for maintaining pluripotent hES cell lines more safely and economically

    Rapamycin Response in Tumorigenic and Non-Tumorigenic Hepatic Cell Lines

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    The mTOR inhibitor rapamycin has anti-tumor activity across a variety of human cancers, including hepatocellular carcinoma. However, resistance to its growth inhibitory effects is common. We hypothesized that hepatic cell lines with varying rapamycin responsiveness would show common characteristics accounting for resistance to the drug.We profiled a total of 13 cell lines for rapamycin-induced growth inhibition. The non-tumorigenic rat liver epithelial cell line WB-F344 was highly sensitive while the tumorigenic WB311 cell line, originally derived from the WB-F344 line, was highly resistant. The other 11 cell lines showed a wide range of sensitivities. Rapamycin induced inhibition of cyclin E-dependent kinase activity in some cell lines, but the ability to do so did not correlate with sensitivity. Inhibition of cyclin E-dependent kinase activity was related to incorporation of p27(Kip1) into cyclin E-containing complexes in some but not all cell lines. Similarly, sensitivity of global protein synthesis to rapamycin did not correlate with its anti-proliferative effect. However, rapamycin potently inhibited phosphorylation of two key substrates, ribosomal protein S6 and 4E-BP1, in all cases, indicating that the locus of rapamycin resistance was downstream from inhibition of mTOR Complex 1. Microarray analysis did not disclose a unifying mechanism for rapamycin resistance, although the glycolytic pathway was downregulated in all four cell lines studied.We conclude that the mechanisms of rapamycin resistance in hepatic cells involve alterations of signaling downstream from mTOR and that the mechanisms are highly heterogeneous, thus predicting that maintaining or promoting sensitivity will be highly challenging

    Population Attributable Fraction of Smoking and Metabolic Syndrome on Cardiovascular Disease Mortality in Japan: a 15-Year Follow Up of NIPPON DATA90

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    <p>Abstract</p> <p>Background</p> <p>Smoking and metabolic syndrome are known to be related to cardiovascular diseases (CVD) risk. In Asian countries, prevalence of obesity has increased and smoking rate in men is still high. We investigated the attribution of the combination of smoking and metabolic syndrome (or obesity) to excess CVD deaths in Japan.</p> <p>Methods</p> <p>A cohort of nationwide representative Japanese samples, a total of 6650 men and women aged 30-70 at baseline without history of CVD was followed for 15 years. Multivariate-adjusted hazard ratio for CVD death according to the combination of smoking status and metabolic syndrome (or obesity) was calculated using Cox proportional hazard model. Population attributable fraction (PAF) of CVD deaths was calculated using the hazard ratios.</p> <p>Results</p> <p>During the follow-up period, 87 men and 61 women died due to CVD. The PAF component of CVD deaths in non-obese smokers was 36.8% in men and 11.3% in women, which were higher than those in obese smokers (9.1% in men and 5.2% in women). The PAF component of CVD deaths in smokers without metabolic syndrome was 40.9% in men and 11.9% in women, which were also higher than those in smokers with metabolic syndrome (7.1% in men and 3.9% in women).</p> <p>Conclusion</p> <p>Our results indicated that a large proportion of excess CVD deaths was observed in smokers without metabolic syndrome or obesity, especially in men. These findings suggest that intervention targeting on smokers, irrespective of the presence of metabolic syndrome, is still important for the prevention of CVD in Asian countries.</p
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