143 research outputs found

    Study on carbon monoxide, carbon dioxide and oxygen competitive adsorption properties of bituminous coals

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    In order to clarify the adsorption pattern between coal and CO, CO2 and O2, the competition between CO and CO2 and O2 in coal is studied. Qianjiaying bituminous coal is used as the research object, and the molecular unit parameters are calculated by quantitative analysis method based on the experimental results of Fourier transform infrared spectroscopy (FTIR). The molecular cell structure of Qianjiaying bituminous coal is constructed (C1160H860O80N20). To verify the accuracy of the model, the infrared spectrum of molecules is simulated by quantum chemical calculation, and the calculated results are basically consistent with the experimental results. On this basis, the effects of pressure(0−16 MPa) and temperature(20−60 ℃) on the adsorption of CO, CO2 and O2 by coal are investigated by using the Grand canonical Monte Carlo (GCMC) and molecular dynamics (MD) methods. From the experimental results, it can be concluded that the fitted isothermal adsorption curves conformed to the Langmuir equation. Under the same pressure, the adsorption capacity of CO, CO2 and O2 is weaker as the temperature increases. At the same temperature, there is a positive correlation trend between the burial pressure of coal seam and the adsorption amount. The magnitude of adsorption of single gases CO, CO2 and O2 is CO2 > O2 > CO, and CO2 can reach saturation adsorption state in the first. The competitive adsorption results of binary gases show that the adsorption selectivity of CO2/CO has obvious advantages in low-pressure or shallow buried coal seams. However, the adsorption selectivity of O2/CO did not change significantly with the change of pressure. The competitive adsorption capacity of CO2 is greater than that of CO, and the adsorption capacity of CO2 decreases with the increase of CO concentration; The competitive adsorption of O2 is greater than CO when the ratio of CO to O2 molar concentration is ≤ 1, but the adsorption of CO is greater than O2 when the molar concentration of CO is much greater than O2. Therefore, the molar concentration of CO is high, which inhibits the adsorption capacity of CO2 and O2. In other words, in bituminous coal seams with high abnormal CO concentration, the effect of using CO2 injection to control fire extinguishing is not significant, so the amount of air leakage from the working face should also be controlled to prevent CO from desorption to the coal body and to ensure that the CO concentration in the well is within the permissible range

    The effect of proteoglycans inhibited by RNA interference on metastatic characters of human salivary adenoid cystic carcinoma

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    <p>Abstract</p> <p>Background</p> <p>Salivary adenoid cystic carcinoma (SACC) is one of the most common malignancies of salivary gland. Recurrence or/and early metastasis is its biological properties. In SACC, neoplastic myoepithelial cells secrete proteoglycans unconventionally full of the cribriform or tubular and glandular structures of SACC. Literatures have demonstrated that extracellular matrix provided an essential microenvironment for the biological behavior of SACC. However, there is rare study of the effect of proteoglycans on the potential metastasis of SACC.</p> <p>In this study, human xylosyltransferase-I (XTLY-I) gene, which catalyzes the rate-limited step of proteoglycans biosynthesis, was knocked down by RNA interference (RNAi) to inhibit the proteoglycans biosynthesis in SACC cell line with high tendency of lung metastasis (SACC-M). The impact of down-regulated proteoglycans on the metastasis characters of SACC-M cells was analyzed and discussed. This research could provide a new idea for the clinical treatment of SACC.</p> <p>Methods</p> <p>The eukaryotic expression vector of short hairpin RNA (shRNA) targeting XTLY-I gene was constructed and transfected into SACC-M cells. A stably transfectant cell line named SACC-M-WJ4 was isolated. The XTLY-I expression was measured by real-time PCR and Western blot; the reduction of proteoglycans was measured. The invasion and metastasis of SACC-M-WJ4 cells were detected; the effect of down-regulated proteoglycans on the potential lung metastasis of nude mice was observed, respectively.</p> <p>Results</p> <p>The shRNA plasmid targeting XTLY-I gene showed powerful efficiency of RNAi. The mRNA level of target gene decreased by 86.81%, the protein level was decreased by 80.10%, respectively. The silence of XTLY-I gene resulted in the reduction of proteoglycans significantly in SACC-M-WJ4 cells. The inhibitory rate of proteoglycans was 58.17% (24 h), 66.06% (48 h), 57.91% (72 h), 59.36% (96 h), and 55.65% (120 h), respectively. The reduction of proteoglycans suppressed the adhesion, invasion and metastasis properties of SACC-M cells, and decreased the lung metastasis of SACC-M cells markedly either.</p> <p>Conclusion</p> <p>The data suggested that the silence of XTLY-I gene in SACC-M cells could suppress proteoglycans biosynthesis and secretion significantly. The reduction of proteoglycans inhibited cell adhesion, invasion and metastasis of SACC-M cells. There is a close relationship between proteoglycans and the biological behavior of SACC.</p

    Exploratory Study on the Methodology of Fast Imaging of Unilateral Stroke Lesions by Electrical Impedance Asymmetry in Human Heads

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    Stroke has a high mortality and disability rate and should be rapidly diagnosed to improve prognosis. Diagnosing stroke is not a problem for hospitals with CT, MRI, and other imaging devices but is difficult for community hospitals without these devices. Based on the mechanism that the electrical impedance of the two hemispheres of a normal human head is basically symmetrical and a stroke can alter this symmetry, a fast electrical impedance imaging method called symmetrical electrical impedance tomography (SEIT) is proposed. In this technique, electrical impedance tomography (EIT) data measured from the undamaged craniocerebral hemisphere (CCH) is regarded as reference data for the remaining EIT data measured from the other CCH for difference imaging to identify the differences in resistivity distribution between the two CCHs. The results of SEIT imaging based on simulation data from the 2D human head finite element model and that from the physical phantom of human head verified this method in detection of unilateral stroke

    Quantitative index of EIT based on 3D abdominal bleeding simulation model

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    According CT images, a 3D abdominal bleeding simulation model with real shape was set up using COMOSOL Multi-physics. By parameter sweeping, the surface measurement data for EIT were obtained while bleeding from 0~800ml. Total relative changes (TRC) of the data were calculated, shown a linear correlation (R>0.99) with bleeding volume (BV), which implies TRC be a good quantitative index to indicate BV

    Deformation mechanism and microstructure evolution during on-line heating rolling of AZ31B Mg thin sheets

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    An AZ31B sheets were processed by on-line heating rolling (ON-LHR) in five passes. Roll and sheets temperatures were 473 K and 533 K, respectively. The grain size was reduced in the first three roll passes, to a minimum of 4.1 μm, due to dynamic recrystallization, and coarsened in the last two passes due to a combination of dynamic recrystallization and grain growth. The yield strength, ultimate tensile strength and elongation to fracture reached 232 MPa, 347 MPa and 21% in the rolling direction. The maximum yield strength occurred after the fourth pass. The maximum is attributed to the small grain size and the formation of networks of sub-grains and deformed grains. The rolled sheets had a strong basal texture, which was largely unchanged with the number of roll passes. The existence of the strong texture after rolling indicated discontinuous dynamic recrystallization

    Molecular epidemiology of hepatitis E virus infections in Shanghai, China

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    <p>Abstract</p> <p>Background</p> <p>Hepatitis E virus (HEV) causes acute or fulminant hepatitis in humans and is an important public health concern in many developing countries. China has a high incidence of HEV epidemics, with at least three genotypes (1, 3 and 4) and nine subtypes (1b, 1c, 3b, 4a, 4b, 4d, 4g, 4h and 4i) so far identified. Since genotype 3 and the newly identified subtype 4i have been exclusively limited geographically to Shanghai and its neighboring provinces, the epidemiology of HEV infections within the municipality, a major industrial and commercial center, deserves closer attention.</p> <p>Findings</p> <p>A total of 65 sequences, 60 located within the HEV SH-SW-zs1 genome [GenBank:<ext-link ext-link-id="EF570133" ext-link-type="gen">EF570133</ext-link>], together with five full-length swine and human HEV genomic sequences, all emanating from Shanghai, were retrieved from GenBank. Consistent with the primary role of genotype 4 in China overall, analysis of the sequences revealed this to have been the dominant genotype (58/65) in Shanghai. Six HEV subtypes (3b, 4a, 4b, 4d, 4h and 4i) were also represented. However, although subtype 4a is the dominant subtype throughout China, subtype 4i (29/65) was the most prevalent subtype among the Shanghai sequences, followed by subtypes 4d (10/65) and 4h (9/65). Subtypes 4h, 4i and 4d were found in both swine and humans, whereas 4b was found only in swine and subtype 4a only in humans.</p> <p>Conclusions</p> <p>Six different swine and human HEV subtypes have so far been documented in Shanghai. More molecular epidemiological investigations of HEV in swine, and particularly among the human population, should be undertaken.</p

    Disease phenotyping using deep learning: A diabetes case study

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    Characterization of a patient clinical phenotype is central to biomedical informatics. ICD codes, assigned to inpatient encounters by coders, is important for population health and cohort discovery when clinical information is limited. While ICD codes are assigned to patients by professionals trained and certified in coding there is substantial variability in coding. We present a methodology that uses deep learning methods to model coder decision making and that predicts ICD codes. Our approach predicts codes based on demographics, lab results, and medications, as well as codes from previous encounters. We are able to predict existing codes with high accuracy for all three of the test cases we investigated: diabetes, acute renal failure, and chronic kidney disease. We employed a panel of clinicians, in a blinded manner, to assess ground truth and compared the predictions of coders, model and clinicians. When disparities between the model prediction and coder assigned codes were reviewed, our model outperformed coder assigned ICD codes.Comment: Machine Learning for Health (ML4H) Workshop at NeurIPS 2018 arXiv:cs/010120

    Electrochemical Impedance Spectroscopy Study on Phase Transformation of Cu6Sn5 Alloy Anode

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    The Cu-Sn alloy electrode was prepared by a one-step electrodepositing method using rough Cu foil as the substrate, and was determined as the intermetallic composite Of Cu6Sn5 using an X-ray diffraction (XRD) method. The electrode surface morphology was analyzed by scanning electron microscopy (SEM) which displayed "small islands" structure with many nano-particles on it. The first discharge and charge capacities were determined as 461 and 405 mAh.g(-1), respectively. Electrochemical impedance spectra (EIS) indicated that there appeared three arcs in the Nyquist plots respectively representing the impedance of solid electrolyte interphase film, charge transfer and phase transformation in the first lithiation, and their evolutive principles were also investigated
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