982 research outputs found

    Differentiation of silane adsorption onto model E-glass surfaces from mixed solutions of amino and glycidyl silanes

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    Mixed silanes are often used as coupling agents in sizings for glass fibres. A technique has been developed which enables the preferential adsorption of a particular silane onto a model E-glass from a mixed aqueous silane solution to be probed. It is shown that γ-Aminopropyltriethoxysilane (APS) is preferentially adsorbed over γ-glycidoxypropyltrimethoxysilane (GPS) onto model E-glass fibres. High resolution X-ray photoelectron spectroscopy (XPS) has been employed to investigate the nature of silane deposits. Differentiation between the hydrolysed silane deposit and the model silica-based glass substrate was achieved by Si2p curve fitting. The extent of total silane adsorption onto model E-glass fibres was determined from the intensity of CSiO3 peak. In the case of APS/GPS mixed silanes, the N1s peak intensity provides the concentration of APS in the deposit. By comparing the relative intensities of the components in the Si2p3/2 and Si2p1/2 peaks for SiO4 and CSiO3 with the intensity of the N1s peak an assessment of differential adsorption proved possible

    The differential adsorption of silanes from solution onto model E-glass surfaces using high resolution XPS

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    γ-aminopropyltriethoxysilane (APS), γ-mercaptopropyltrimethoxysilane (MPS) and their mixture have been adsorbed onto acid-treated model E-glass fibres from aqueous solution with different concentrations. High resolution X-ray photoelectron spectroscopy (XPS) has been employed to characterize APS and MPS single silane coatings and the selective adsorption of APS/MPS mixed silane coating. It is found that the Si contribution from the silane can be distinguished from the Si contribution from the acid-treated E-glass fibres by fitting Si2p1/2 and Si2p3/2 peaks with components for CSiO3 and SiO4 environments. The adsorption isotherms of APS and MPS have been obtained by comparing the atomic concentrations of N, S and CSiO3 groups. APS and MPS are equally adsorbed from 0.1% APS/MPS mixed silane solution, however, MPS dominates the deposit on model E-glass fibres to a depth corresponding to the take-off-angle of 45º when it is adsorbed from 0.5% and 1.0% APS/MPS mixed silane solutions

    A fabrication history based strain-fatigue model for prediction of crack initiation in a radial loading wheel

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    A strain-based fatigue model concerning fabrication history is applied to predict the fatigue life of a commercial car wheel under radial loads. As the prior conditions, the strain fatigue testing is performed on standard specimen of DP590 and FB540 steels at various fabrication states, including raw materials, pre-strain and pre-strain + bake. Furthermore, the strain distribution of car wheel during its rotation under radial loads is simulated via ANSYS. The fatigue properties mainly determined by crack initiation of car wheels at various fabrication states are predicted via local stress–strain method, in which the scale and surface factors are also taken into account. The radial fatigue testing is carried out, and the results are used to validate the present model. The fracture mechanism is analysed using FEI Nova 400 field emission gun scanning electron microscope

    Degradación de algunos compuestos volátiles de aceites de onagra bajo un proceso UV/TiO2

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    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 aldehídos volátiles, que darían 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 características fisicoquímicas 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 podría 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)

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    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

    Phase Transformation of Nb in Carburized Zone of 25Cr35NiNb+MA Alloy After Service

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    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

    NARROMI: a noise and redundancy reduction technique improves accuracy of gene regulatory network inference.

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    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

    Estimation of Canadian manure and fertilizer nitrogen application rates for crops at the soil polygon level using the CANB v2.0 model

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    Non-Peer ReviewedIn response to national environmental and climate change modeling projects such as agri-environmental indicators, greenhouse gases, carbon sequestration and policy scenarios, fertilizer N and manure nitrogen N application rates were estimated for individual crops at the Soil Landscapes of Canada (SLC) polygon scale (1:1 million). This database provides an estimate of the actual amount of N applied per crop and per hectare, based on provincial fertilization recommendations, manure production levels of each type of livestock and reported amounts of fertilizer sold. The database is being incorporated into ongoing programs related to Kyoto accounting of greenhouse gas emissions, environmental performance and policy formulation at Agriculture and Agri-Food Canada. A standardized Canadian Agricultural Nitrogen Budget (CANB v2.0) model was developed to calculate the agri-environmental indicators Residual Soil Nitrogen (RSN) and Indicator of Risk of Water Contamination by Nitrogen (IROWC-N). CANB is a national-level model that operates on 3500 SLC polygons using generalized soil, landscape, climate, and Census of Agriculture socioeconomic data. It is designed to provide a regional update on the soil N balance for each of the census years of 1981, 1986, 1991, 1996, 2001 and into the future. The database and model have the capability to calculate a number of different components of the nutrient balance, including the inputs of fertilizer N, manure N, biological N and atmospheric N and N the removals of N in the harvested proportion of the crop and via nitrogenous gas emissions. This paper describes the procedures to estimate fertilizer N and manure N inputs for each crop within each polygon. It includes: (i) the compilation of soil-specific N application rates from provincial extension guidelines, (ii) the calculation of total manure N production from animal numbers and excretion rates, (iii) the calculation of available manure N after storage and handling losses, and (iv) the recommended and adjusted nitrogen application rates. Adjustments were made to account for the amount of inorganic N in the manure applied to the various crops. The adjusted nitrogen rate data was also reconciled with the provincial fertilizer sales data

    Effectiveness of acupoint hot compress on early puerperal rehabilitation of parturients after natural childbirth: study protocol for a prospective, multi-center, randomized controlled clinical trial

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    Early puerperal rehabilitation can interfere with a woman's ability to care for herself and her infant. Acupoint hot compress, with a combination of acupoints and natural physical agent heat, has significant potential to alleviate symptoms experienced during early puerperium. Current evidence regarding the effects of acupoint hot compress therapy on early puerperal rehabilitation is insufficient. The aim of this study is to address this with a multi-center design and large sample size. This is a prospective, multi-center, and randomized controlled clinical trial. A total of 1400 nulliparous women with a singleton pregnancy experiencing natural childbirth from 14 hospitals will be enrolled and randomly allocated to either an intervention group or a control group in a 1:1 ratio. Subjects in the control group will only receive routine postpartum care. In addition to routine postpartum care, the subjects in the intervention group will be administered a 4-hour acupoint hot compress with a constant temperature of 45±2°C respectively within 30 minutes after delivery, 24 hours and 48 hours after delivery. The primary outcome will be the time elapsed from delivery to the first urination. The secondary outcomes will be postpartum uterine contraction pain intensity, the Edinburgh Postnatal Depression Scale for screening postpartum depression and the assessment of lactation including recording the lactation initiation time, postpartum diet, appetite, weight, neonatal weight. These results will provide evidence for obstetricians and parturients on considering nonpharmacologic and noninvasive intervention in early puerperal rehabilitation
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