203 research outputs found

    Vapor-liquid equilibrium properties of binary mixture refrigerants (R1234ZE+R290, R290+R227ea)

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    The vapor-liquid equilibrium data is an important part of thermophysical properties of a new refrigerant. Theoretical predictions and experimental measurements of vapor-liquid equilibrium data of a new mixed working fluid become to be an urgent need for the researches on alternative refrigerants. The vapor-liquid equilibrium curves of binary mixtures (R1234ze(E)+R290, R290+R227ea) were simulated by COSMO-RS model which are based on quantum chemistry. The simulation results could accord with the experimental data well. It was concluded that COSMO-RS simulation method is feasible to predict the vapor-liquid equilibrium properties of mixed refrigerants

    Influence of the Mega-Urban Heat Island on Spatial Transfer of Summer Thermal Comfort: Evidence from Tianjin, China

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    Human thermal comfort in urban spaces deteriorates as rapid urbanization proceeds. However, effective tests and discoveries of spatial statistic patterns are currently absent. This study collected remote sensing images and measured meteorological data of the summers of 1992–2017, Tianjin of China and aims to clarify patterns of spatial transfer and thermal comfort changes caused by a mega-UHI (Urban Heat Island). An analytic transfer matrix and the spatial autocorrelation were developed to study spatial pattern changes and features of the spatial transfer of thermal comfort caused by UHI. Results show these patterns in the affected areas can be divided into different levels: patterns of low-level affected areas transferred by circular expansion into block-mass jumping, while the position of high-level affected areas remains stable. The spatial transfer of thermal comfort in the affected areas shows two apparent stages: the transfer from areas of high-density and low-storied buildings and into areas of multiple storied buildings, and transfer from areas of low and multiple storied buildings into those of high storied buildings. This implies changes in urban planning can guide spatial, structural, and functional evolution. The study identifies features of spatial change and spatial patterns related to the influence of Mega-UHI on thermal comfort

    Optimization of “Deoxidation Alloying” Batching Scheme

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    In this paper, a mathematical model was established to predict the deoxidation alloying and to optimize the type and quantity of input alloys. Firstly, the GCA method was used to obtain the main factors affecting the alloy yield of carbon and manganese based on the historical data. Secondly, the alloy yield was predicted by the stepwise MRA, the BP neural network and the regression SVM models, respectively. The conclusion is that the regression SVM model has the highest prediction accuracy and the maximum deviation between the test set prediction result and the real value was only 0.0682 and 0.0554. Thirdly, in order to reduce the manufacturer's production cost, the genetic algorithm was used to calculate the production cost mathematical programming model. Finally, sensitivity analysis was performed on the prediction model and the cost optimization model. The unit price of 20% of the alloy raw materials was increased by 20%, and the total cost change rate was 0.7155%, the lowest was -0.4297%, which proved that the mathematical model established presented strong robustness and could be certain reference value for the current production of iron and steel enterprises

    Comparative transcriptome analysis of PBMC from HIV patients pre- and post-antiretroviral therapy

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    Infections of the human immunodeficiency virus (HIV) trigger host immune responses, but the virus can destroy the immune system and cause acquired immune deficiency syndrome (AIDS). Highly active antiretroviral therapy (HAART) can suppress viral replication and restore the impaired immune function. To understand HIV interactions with host immune cells during HAART, the transcriptomes of peripheral blood mononuclear cells (PBMC) from HIV patients and HIV negative volunteers before and two weeks after HAART initiation were analyzed using RNA sequencing (RNA-Seq) technology. Differentially expressed genes (DEGs) in response to HAART were firstly identified for each individual, then common features were extracted by comparing DEGs among individuals and finally HIV-related DEGs were obtained by comparing DEGs between the HIV patients and HIV negative volunteers. To demonstrate the power of this approach, minimum numbers of patients (one HIV alone; one HIV + tuberculosis, TB; one HIV + TB with immune reconstitution inflammatory syndrome during HAART) and two HIV negative volunteers were used. More than 15,000 gene transcripts were detected in each individual sample. Fourteen HAART up-regulated and eleven down-regulated DEGs were specifically identified in the HIV patients. Among them, nine up-regulated (CXCL1, S100P, AQP9, BASP1, MMP9, SOD2, LIMK2, IL1R2 and BCL2A1) and nine down-regulated DEGs (CD160, CD244, CX3CR1, IFIT1, IFI27, IFI44, IFI44L, MX1 and SIGLEC1) have already been reported as relevant to HIV infections in the literature, which demonstrates the credibility of the method. The newly identified HIV-related genes (up-regulated: ACSL1, GPR84, GPR97, ADM, LRG1; down-regulated: RASSF1, PATL2) were empirically validated using qRT-PCR. The Gene Set Enrichment Analysis (GSEA) was also used to determine pathways significantly affected by HAART. GSEA further confirmed the HAART relevance of five genes (ADM, AQP9, BASP1, IL1R2 and MMP9). The newly identified HIV-related genes, ADM (which encodes Adrenomedullin), a peptide hormone in circulation control, may contribute to HIV-associated hypertensions, providing new insights into HIV pathology and novel strategies for developing anti-HIV target. More importantly, we demonstrated that comparative transcriptome analysis is a very powerful tool to identify infection related DEGs using a very small number of samples. This approach could be easily applied to improve the understanding of pathogen-host interactions in many infections and anti-infection treatments

    Zinc finger and interferon-stimulated genes play a vital role in TB-IRIS following HAART in AIDS

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    Aim: Co-infection in HIV-1 patients with Mycobacterium tuberculosis poses considerable risk of developing the immune reconstitution inflammatory syndrome (IRIS), especially upon the initiation of antiretroviral therapy (ART). Methodology & results: For transcriptomic analysis, peripheral blood mononuclear cells’ whole gene expression was used from three patient groups: HIV+ (H), HIV-TB+ (HT), HIV-TB+ with IRIS (HTI). Pathway enrichment and functional analysis was performed before and after highly active ART. Genes in the interferon-stimulating and ZNF families maintained tight functional interaction and tilted the balance in favor of TB-IRIS. Discussion & conclusion: The functional impairment of interaction between ZNF genes and interferon-stimulated genes, along with higher expression of S100A8/S100A9 genes possibly forms the genomic basis of TB-IRIS in a subset of HIV patients while on highly active ART
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