431 research outputs found

    Graphite flake self-retraction response based on potential seeking

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    The high elastic modulus and interlayer strengths of graphite flakes make them a durable solid superlubricant. Apart from this, they have configurable electrical properties, exhibit quantum Hall effects, and possess a myriad of useful photonic properties. The self-retraction behavior of graphite flakes can have significant impact on the creation of ordered stacks for various applications because any accidental or intentional displacement of the top flake over the stacks below may result in a misalignment of the carbon-carbon atomic arrangement which, in turn, can have influence over the electrical and photonic properties. It has also been revealed that there was a tendency of the displaced microflake to fail at times to return to its original starting position and orientation. Here, we elucidate this behavior by considering the influence of the interlayer potential forces based on minimal potential energy seeking. The maps of the parameters interrogated here provide the ability for precautions to be undertaken. They also potentially permit the creation of an array of microflake stacks in which the metastable states permit different information to be encoded by virtue of the differentiated photonic or electrical characteristics readable from each array site

    Antibiotic-Induced Disruption of Gut Microbiota Alters Local Metabolomes and Immune Responses

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    Gut microbiome plays an essential role in modulating host immune responses. However, little is known about the interaction of microbiota, their metabolites and relevant inflammatory responses in the gut. By treating the mice with three different antibiotics (enrofloxacin, vancomycin, and polymixin B sulfate), we aimed to investigate the effects of different antibiotics exposure on gut microbiota, microbial metabolism, inflammation responses in the gut, and most importantly, pinpoint the underlying interactions between them. Although the administration of different antibiotics can lead to different effects on mouse models, the treatment did not affect the average body weight of the mice. A heavier caecum was observed in vancomycin treated mice. Treatment by these three antibiotics significantly up-regulated gene expression of various cytokines in the colon. Enrofloxacin treated mice seemed to have an increased Th1 response in the colon. However, such a difference was not found in mice treated by vancomycin or polymixin B sulfate. Vancomycin treatment induced significant changes in bacterial composition at phylum and family level and decreased richness and diversity at species level. Enrofloxacin treatment only induced changes in composition at family presenting as an increase in Prevotellaceae and Rikenellaceae and a decrease in Bacteroidaceae. However, no significant difference was observed after polymixin B sulfate treatment. When compared with the control group, significant metabolic shift was found in the enrofloxacin and vancomycin treated group. The metabolic changes mainly occurred in Valine, leucine, and isoleucine biosynthesis pathway and beta-Alanine metabolism in enrofloxacin treated group. For vancomycin treatment metabolic changes were mainly found in beta-Alanine metabolism and Alanine, aspartate and glutamate metabolism pathway. Moreover, modifications observed in the microbiota compositions were correlated with the metabolite concentrations. For example, concentration of pentadecanoic acid was positively correlated with richness of Rikenellaceae and Prevotellaceae and negatively correlated with Enterobacteriaceae. This study suggests that the antibiotic-induced changes in gut microbiota might contribute to the inflammation responses through the alternation of metabolic status, providing a novel insight regarding a complex network that integrates the different interactions between gut microbiota, metabolic functions, and immune responses in host

    Polymorphisms of toll-like receptors 2 and 9 and severity and prognosis of bacterial meningitis in Chinese children

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    Toll-like receptors (TLRs) play a crucial role in innate immunity, protecting the host from bacterial pathogens. We investigated whether bacterial meningitis (BM) in children was associated with gene polymorphisms in TLR2 (rs3804099), TLR3 (rs3775291 and rs3775290) and TLR9 (rs352139 and rs352140). Blood samples were taken from 218 child patients with confirmed BM and 330 healthy adult controls (HC) and polymorphisms of these genes were analyzed by PCR-based sequencing. For TLR2 rs3804099, frequencies of the minor allele C were markedly higher in patients with severe BM (defined as CSF glucose concentration <= 1.5 mmol/L and seizures) than those without (43.5% and 40.1% vs. 30.1% and 29.1%, p = 0.008 and p = 0.016, respectively). For TLR9 rs352139, patients who carried genotype AA and minor allele A developed seizures less often than those without (OR = 0.289, p = 0.003 and OR = 0.568, p = 0.004, respectively). However, for TLR9 rs352140, patients who carried genotype TT and minor allele T developed seizures more often than those without (OR = 3.385, p = 0.004 and OR = 1.767, p = 0.004, respectively). Our finding suggested that genetic variations in TLR2 and TLR9 are associated with severity and prognosis of bacterial meningitis in Chinese children. However, the results should be interpreted with caution since the number of subjects included was limited

    Differentiation-inducing and anti-proliferative activities of isoliquiritigenin and all-trans-retinoic acid on B16F0 melanoma cells: Mechanisms profiling by RNA-seq

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    Melanoma is a cancer that arises from melanocytes, specialized pigmented cells that are found predominantly in the skin. The incidence of malignant melanoma has significantly increased over the last decade. With the development of therapy, the survival rate of some kind of cancer has been improved greatly. But the treatment of melanoma remains unsatisfactory. Much of melanoma's resistance to traditional chemotherapy is believed to arise intrinsically, by virtue of potent growth and cell survival-promoting genetic alteration. Therefore, significant attention has recently been focused on differentiation, therapy, as well as differentiation inducer compounds. In previous study, we found isoliquiritigenin (ISL), a natural product extracted from licorice, could induce B16F0 melanoma cell differentiation. Here we investigated the transcriptional response of melanoma differentiation process induced by ISL and all-trans-retinoic acid (RA). Results showed that 390 genes involves in 201 biochemical pathways were differentially expressed in ISL treatment and 304 genes in 193 pathways in RA treatment. Differential expressed genes (DGEs, fold-change (FC) >= 10) with the function of anti-proliferative and differentiation inducing indicated a loss of grade malignancy characteristic. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis indicated glutathione metabolism, glycolysis/gluconeogenesis and pentose phosphate pathway were the top three relative pathway perturbed by ISL, and mitogen-activated protein kinase (MAPK) signaling pathway was the most important pathway in RA treatment. In the analysis of hierarchical clustering of DEGs, we discovered 72 DEGs involved in the process of drug action. We thought Cited1, Tgm2, Xaf1, Cd59a, Fbxo2, Adh7 may have critical role in the differentiation of melanoma. The evidence displayed herein confirms the critical role of reactive oxygen species (ROS) in melanoma pathobiology and provides evidence for future targets in the development of next-generation biomarkers and therapeutics. (C) 2016 Elsevier B.V. All rights reserved

    Toll like receptor7 polymorphisms in relation to disease susceptibility and progression in Chinese patients with chronic HBV infection

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    Toll-like receptors (TLRs) play a key role in innate and adaptive immunity, protecting the host from viral pathogens. We studied the effect of TLR7 polymorphisms on disease susceptibility and progression of chronic hepatitis B (CHB) infection in Chinese adults. Blood samples were taken from 612 patients with confirmed CHB, hepatitis B virus (HBV)-related liver cirrhosis (LC) or hepatocellular carcinoma (HCC) and 293 controls. TLR7 polymorphisms (rs179010-C > T, rs2074109-T > C, and rs179009-A > G) were analyzed by PCR-based sequencing. A significantly higher frequency of TLR7 rs179010 C allele was found in male CHB patients than in controls (74.8% vs 59.5%, P = 0.002). The frequency of rs179009 G allele was markedly increased with disease progression when male patients with CHB, LC and HCC were compared (P = 0.012). The haplotype CTA was significantly associated with an increased susceptibility to CHB among male patients (P = 0.000). Frequency of the haplotype CTG was higher in male patients with HCC than CHB (P = 0.005). No such differences in these allele frequencies were found between female patients and controls. Our results indicated that TLR7 polymorphisms play an important role in disease susceptibility and the progression of CHB infections in Chinese adults, and may partly explain the high incidence of HBV related diseases in Chinese men

    Design and Analysis of Nanotube-Based Memory Cells

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    In this paper, we proposed a nanoelectromechanical design as memory cells. A simple design contains a double-walled nanotube-based oscillator. Atomistic materials are deposed on the outer nanotube as electrodes. Once the WRITE voltages are applied on electrodes, the induced electromagnetic force can overcome the interlayer friction between the inner and outer tubes so that the oscillator can provide stable oscillations. The READ voltages are employed to indicate logic 0/1 states based on the position of the inner tube. A new continuum modeling is developed in this paper to analyze large models of the proposed nanoelectromechanical design. Our simulations demonstrate the mechanisms of the proposed design as both static and dynamic random memory cells

    Choroidal thickness in school children: The Gobi Desert Children Eye Study

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    Classification of Camellia (Theaceae) Species Using Leaf Architecture Variations and Pattern Recognition Techniques

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    Leaf characters have been successfully utilized to classify Camellia (Theaceae) species; however, leaf characters combined with supervised pattern recognition techniques have not been previously explored. We present results of using leaf morphological and venation characters of 93 species from five sections of genus Camellia to assess the effectiveness of several supervised pattern recognition techniques for classifications and compare their accuracy. Clustering approach, Learning Vector Quantization neural network (LVQ-ANN), Dynamic Architecture for Artificial Neural Networks (DAN2), and C-support vector machines (SVM) are used to discriminate 93 species from five sections of genus Camellia (11 in sect. Furfuracea, 16 in sect. Paracamellia, 12 in sect. Tuberculata, 34 in sect. Camellia, and 20 in sect. Theopsis). DAN2 and SVM show excellent classification results for genus Camellia with DAN2's accuracy of 97.92% and 91.11% for training and testing data sets respectively. The RBF-SVM results of 97.92% and 97.78% for training and testing offer the best classification accuracy. A hierarchical dendrogram based on leaf architecture data has confirmed the morphological classification of the five sections as previously proposed. The overall results suggest that leaf architecture-based data analysis using supervised pattern recognition techniques, especially DAN2 and SVM discrimination methods, is excellent for identification of Camellia species

    3-D Ultrastructure of O. tauri: Electron Cryotomography of an Entire Eukaryotic Cell

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    The hallmark of eukaryotic cells is their segregation of key biological functions into discrete, membrane-bound organelles. Creating accurate models of their ultrastructural complexity has been difficult in part because of the limited resolution of light microscopy and the artifact-prone nature of conventional electron microscopy. Here we explored the potential of the emerging technology electron cryotomography to produce three-dimensional images of an entire eukaryotic cell in a near-native state. Ostreococcus tauri was chosen as the specimen because as a unicellular picoplankton with just one copy of each organelle, it is the smallest known eukaryote and was therefore likely to yield the highest resolution images. Whole cells were imaged at various stages of the cell cycle, yielding 3-D reconstructions of complete chloroplasts, mitochondria, endoplasmic reticula, Golgi bodies, peroxisomes, microtubules, and putative ribosome distributions in-situ. Surprisingly, the nucleus was seen to open long before mitosis, and while one microtubule (or two in some predivisional cells) was consistently present, no mitotic spindle was ever observed, prompting speculation that a single microtubule might be sufficient to segregate multiple chromosomes

    Effects of TLR7 Polymorphisms on the Susceptibility and Progression of HIV-1 Infection in Chinese MSM Population

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    Toll-like receptor (TLR) 7 plays a key role in innate and adaptive immunity for HIV-1 infection. We evaluated the effect of TLR7 polymorphisms on disease susceptibility and progression of HIV-1 infection in Chinese MSM (men who have sex with men). Blood samples were taken from 270 patients with laboratory confirmed HIV infection, 196 male controls were tested, and three TLR7 intronic polymorphisms (rs179010-C > T, X:12884766; rs2074109-T > C, X:12885330; and rs179009-A > G, X:12885361) were analyzed by PCR-based sequencing. The frequency of TLR7 rs179010 T allele was significantly lower in MSM patients than in controls (P = 0.039). The haplotype TTA was associated with a decreased susceptibility to HIV-1 infection (P = 0.013), especially to acute HIV-1 infection (AHI) (P = 0.002), but not to chronic HIV-1 infection (CHI). Furthermore, the haplotype TTA is linked to slow disease progression in AHI patients (P = 0.002) and a lower viral load (P = 0.042). In contrast, TLR7 rs179009 allele A contributed to a higher set point in AHI patients with rapid progression, and the frequency of rs179009 minor allele G was over-presented in CHI patients. This finding supports a role for genetic variations of TLR7 in susceptibility and disease progression of an HIV-1 infection in Chinese Han population and warrants further studies on the effect of TLR7 polymorphisms on HIV-1 infection in different populations
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