937 research outputs found
Thermal Processes in the Oscillations of Gas Bubbles in Tubes
The forced oscillations of a system consisting of two finite liquid columns in a duct separated by a gas bubble are studied in the linear approximation. It is found that thermal processes in the gas induce a very significant damping in the system, which can exceed viscous damping even in capillaries with a submillimeter diameter. The study is motivated by the possibility of using gas bubbles as actuators in microdevices
Phase Transformation of Nb in Carburized Zone of 25Cr35NiNb+MA Alloy After Service
Abstract25Cr35NiNb+MA alloy is widely used in ethylene pyrolysis furnace tube, the highest service temperature can be 1100°C, and has high resistance to creep and carburization. Ethylene pyrolysis furnace tube will suffer carburizing during service, which lead to phase transformation. Phase transformation of 25Cr35NiNb+MA heat-resistant ethylene pyrolysis furnace tube was investigated after service and the Nb transition during service was discussed. The phase transformation of ethylene pyrolysis furnace tube was characterized with field emission scanning electron microscopy (FE-SEM) equipped with energy dispersive spectrum (EDS). Results reveal that the microstructure of as-cast 25Cr35NiNb+MA alloy contains NbC carbides on the dendrite boundaries. During service at high temperature, the NbC carbides transform to blocky G-phase (Ni16Nb6Si7) between M23C6 and matrix. As the carburizing process occurs, the blocky G-phase (Ni16Nb6Si7) gradually transforms to granular NbC, and distribute at the center of chromium carbide. The granular NbC will improve resistance of creep
OGEE v2: an update of the online gene essentiality database with special focus on differentially essential genes in human cancer cell lines
OGEE is an Online GEne Essentiality database. To enhance our understanding of the essentiality of genes, in OGEE we collected experimentally tested essential and non-essential genes, as well as associated gene properties known to contribute to gene essentiality. We focus on large-scale experiments, and complement our data with text-mining results. We organized tested genes into data sets according to their sources, and tagged those with variable essentiality statuses across data sets as conditionally essential genes, intending to highlight the complex interplay between gene functions and environments/experimental perturbations. Developments since the last public release include increased numbers of species and gene essentiality data sets, inclusion of non-coding essential sequences and genes with intermediate essentiality statuses. In addition, we included 16 essentiality data sets from cancer cell lines, corresponding to 9 human cancers; with OGEE, users can easily explore the shared and differentially essential genes within and between cancer types. These genes, especially those derived from cell lines that are similar to tumor samples, could reveal the oncogenic drivers, paralogous gene expression pattern and chromosomal structure of the corresponding cancer types, and can be further screened to identify targets for cancer therapy and/or new drug development. OGEE is freely available at http://ogee.medgenius.info
Degradación de algunos compuestos volátiles de aceites de onagra bajo un proceso UV/TiO2
Off-flavor is one of the limiting factors in the quality and commercial acceptability of evening primrose oil (EPO). The results of this study demonstrated that ultraviolet light irradiated with titanium dioxide (UV/TiO2) was able to effectively reduce odorous aldehyde concentrations, which would produce undesired flavors. Specifically, reductions in the E-2-Decenal, 1-octen-3-ol and hexanoic acid in EPO reached 50, 75.2 and 61.4% after a UV/TiO2 process of 5 min, respectively. The odor active values (OAV) and hierarchical cluster analysis (HCA) showed that the result of the 5 min group was similar to that of the original oil. In addition, the physicochemical characteristics of EPO after processing did not change significantly. The result of the aroma profile analysis was consistent with the OAV and HCA results. Therefore, it has been concluded that 5 min UV/TiO2 treatment could degrade some volatile compounds and provide a potential deodorization method for industry.El mal sabor es uno de los factores limitantes de la calidad y aceptabilidad comercial del aceite de onagra (EPO). Los resultados de este estudio demostraron que la luz ultravioleta irradiada con dióxido de titanio (UV/TiO2) fue capaz de reducir eficazmente las concentraciones de aldehÃdos volátiles, que darÃan olores no deseados. En concreto, la reducción del E-2-Decenal, 1-octen-3-ol y el ácido hexanoico en EPO alcanzó el 50%, 75,2% y 61,4% respectivamente tras un proceso UV/TiO2 de 5 min. Los valores de olor activo (OAV) y el análisis de conglomerados jerárquicos (HCA) mostraron que el resultado del grupo de 5 min fue similar al del aceite original. Además, las caracterÃsticas fisicoquÃmicas del EPO después del procesamiento no cambiaron significativamente. El resultado del análisis del perfil de aroma fue consistente con nuestro resultado de OAV y HCA. Por lo tanto, se ha llegado a la conclusión de que el tratamiento con UV/TiO2 durante 5 min podrÃa degradar algunos compuestos volátiles y proporcionar un método de desodorización potencial para la industria
Proteomic analysis of the rat ovary following chronic low-dose exposure to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD)
2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) is a ubiquitously distributed endocrine-disrupting chemical and reproductive toxicant. In order to elucidate low-dose TCDD-mediated effects on reproductive or endocrine functions, female Sprague-Dawley rats were orally administered various concentrations (20, 50, or 125 ng/kg once weekly) TCDD for 29 wk. A proteomic analysis of the ovaries by two-dimensional gel electrophoresis and matrix-assisted laser desorption/ionization (MALDI) tandem mass spectrometry showed distinct changes in the levels of several proteins that are relevant markers of TCDD toxicity. Serum estradiol (E2) levels of TCDD-treated animals were markedly lower than control. There were no significant differences in bone mineral density (BMD) of femurs. The body weight of the 125-ng/kg TCDD group was significantly decreased relative to control and there was also a significant reduction in absolute and relative ovarian weights. Expressions of selenium binding protein 2, glutathione S-transferase mu type 3, Lrpap1 protein, NADPH, and peptidylprolyl isomerase D were upregulated, while prohibitin and N-ethylmaleimide-sensitive factor expression levels were downregulated. Data provide further insight into the mechanisms by which TCDD disrupts ovarian function by indicating which differential protein expressions following low-dose TCDD exposure
EGAM Induced by Energetic-electrons and Nonlinear Interactions among EGAM, BAEs and Tearing Modes in a Toroidal Plasma
In this letter, it is reported that the first experimental results are
associated with the GAM induced by energetic electrons (eEGAM) in HL-2A Ohmic
plasma. The energetic-electrons are generated by parallel electric fields
during magnetic reconnection associated with tearing mode (TM). The eEGAM
localizes in the core plasma, i.e. in the vicinity of q=2 surface, and is very
different from one excited by the drift-wave turbulence in the edge plasma. The
analysis indicated that the eEGAM is provided with the magnetic components,
whose intensities depend on the poloidal angles, and its mode numbers are
jm/nj=2/0. Further, there exist intense nonlinear interactions among eEGAM,
BAEs and strong tearing modes (TMs). These new findings shed light on the
underlying physics mechanism for the excitation of the low frequency (LF)
Alfv\'enic and acoustic uctuations.Comment: 5 pages,4 figure
Stripes in Quantum Hall Double Layer Systems
We present results of a study of double layer quantum Hall systems in which
each layer has a high-index Landau level that is half-filled. Hartree-Fock
calculations indicate that, above a critical layer separation, the system
becomes unstable to the formation of a unidirectional coherent charge density
wave (UCCDW), which is related to stripe states in single layer systems. The
UCCDW state supports a quantized Hall effect when there is tunneling between
layers, and is {\it always} stable against formation of an isotropic Wigner
crystal for Landau indices . The state does become unstable to the
formation of modulations within the stripes at large enough layer separation.
The UCCDW state supports low-energy modes associated with interlayer coherence.
The coherence allows the formation of charged soliton excitations, which become
gapless in the limit of vanishing tunneling. We argue that this may result in a
novel {\it ``critical Hall state''}, characterized by a power law in
tunneling experiments.Comment: 10 pages, 8 figures include
NARROMI: a noise and redundancy reduction technique improves accuracy of gene regulatory network inference.
MOTIVATION: Reconstruction of gene regulatory networks (GRNs) is of utmost interest to biologists and is vital for understanding the complex regulatory mechanisms within the cell. Despite various methods developed for reconstruction of GRNs from gene expression profiles, they are notorious for high false positive rate owing to the noise inherited in the data, especially for the dataset with a large number of genes but a small number of samples.
RESULTS: In this work, we present a novel method, namely NARROMI, to improve the accuracy of GRN inference by combining ordinary differential equation-based recursive optimization (RO) and information theory-based mutual information (MI). In the proposed algorithm, the noisy regulations with low pairwise correlations are first removed by using MI, and the redundant regulations from indirect regulators are further excluded by RO to improve the accuracy of inferred GRNs. In particular, the RO step can help to determine regulatory directions without prior knowledge of regulators. The results on benchmark datasets from Dialogue for Reverse Engineering Assessments and Methods challenge and experimentally determined GRN of Escherichia coli show that NARROMI significantly outperforms other popular methods in terms of false positive rates and accuracy.
AVAILABILITY: All the source data and code are available at: http://csb.shu.edu.cn/narromi.htm
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