Search

Liquid oxygen chill-down in a straight horizontal pipe was studied experimentally. The effect of the entrance corner was excluded, and much denser wall temperature sensors along the pipe have been set compared to the present studies. In this way, the chill-down process, as well as the development of the flow pattern, has been drawn for every test. As a result, the mechanism of LO2 chill-down would be obtained for various pressure sections. For cases with stable pressure below 1.25 MPa, liquid rewetting in the pipe is controlled by the propagation of quenching fronts. For cases with a higher pressure, liquid rewetting in the second half of the pipe is controlled by the sudden liquid fill-in. Based on the transition points obtained, heat transfer coefficients on the Leidenfrost point and critical heat flux have been correlated for various pressure sections using new approaches. Conclusions show that the correlation equations are dependent on the chill-down mechanisms. [ABSTRACT FROM AUTHOR]

Liquid oxygen chill-down in a vertical exit-contracted pipe was investigated experimentally. The wall temperatures were recorded in detail to describe the filling and chill-down process of the experimental section. Two quenching fronts, the exit one and the inlet one, were detected, and their propagations were found. Results show that the chill-down process is controlled mainly by the formation and propagation of quenching front, which are determined by the pressure level. With the increase of pressure, the roles of both propagation of quenching front and inlet quenching front undergo decreasing. On the vertical section, the effect of circumferential position was discussed in detail and the dominant point was identified, which determines the boiling transition time of the dominated points on the current cross-section. Based on the experimental data, two correlations were suggested for dominant point and dominated points, respectively, to predict heat flux on Leidenfrost, heat transfer coefficient on Leidenfrost, and critical heat flux. One equation was approved to predict heat transfer coefficient on critical heat flux point for both sorts of points. All of these correlations could produce reliable predictions. [ABSTRACT FROM AUTHOR]

What is known and objectives: Ademetionine 1,4‐Butanedisulfonate (SAMe) enteric‐coated tablets are widely used for treatment of pre‐cirrhotic and cirrhotic intrahepatic cholestasis, as well as intrahepatic cholestasis of pregnancy (ICP), but incomplete clinical data and interference from endogenous substances pose numerous challenges for clinical trial of ademetionine. The objective of this study was to evaluate the pharmacokinetic profile of SAMe enteric‐coated tablets and to assess its food impact and safety in healthy Chinese subjects. Methods: A randomized, open‐label, single‐dose study was carried out to determine the pharmacokinetics of SAMe enteric‐coated tablets administered in both fasted and postprandial conditions. Baseline collection and data adjustment were required to reduce the effect of endogenous substances. Relevant pharmacokinetic data from subjects administered the reference formulation will be disclosed and utilized in this thesis. Results: Twenty‐four subjects with a body mass index (BMI) of 19–24 kg/m2 were enrolled in the study and all completed the trial. The impact of food on the drug was noticeable, with faster absorption in the fasting group (Tmax, 4.50 ± 1.07 and 7.50 ± 1.58 for the fasting and postprandial groups, respectively) but higher exposure in the postprandial group (AUC0–inf, 4021.02 ± 3377.13 and 5087.28 ± 3539.26 for the fasting and postprandial groups, respectively). No serious adverse effects were observed in the fasted and postprandial conditions. What is new and conclusions: The pharmacokinetic profile of SAMe enteric‐coated tablets in healthy Chinese subjects was partially complemented in this study. SAMe enteric‐coated tablets showed promising safety in fasted and postprandial conditions. However, the impact of food on the drug was significant and might access to the absorption site and affect biochemical reactions. [ABSTRACT FROM AUTHOR]

Objectives. Gegen Qinlian decoction (GQD), a Chinese herbal compound, has been widely used in the treatment of ulcerative colitis (UC) in China. However, evidence from systematic reviews (SRs)/meta-analyses (MAs) of GQD in UC remains highly controversial. To collate, evaluate, and synthesize the current evidence, we carried out this study. Methods. SRs/MAs of GQD for UC were obtained from eight databases. Methodological Quality of Systematic Reviews 2 (AMSTAR-2) was utilized to appraise the methodological quality, Preferred Reporting Item for Systematic Reviews and Meta-Analyses (PRISMA) for reporting quality, and Grading of Recommendations Assessment, Development, and Evaluation (GRADE) for evidence quality. Results. Four eligible SRs/MAs were obtained. According to AMSTAR 2, all SRs/MAs were graded as critically low quality. According to PRISMA checklist, all SRs/MAs failed to report the information of protocol and registration. With GRADE, no outcome measure with high-quality evidence was found, and the evidence quality for outcome measures was in the moderate to critically low levels. Conclusions. GQD with conventional medicine (CM) seems to be more effective in UC than CM alone. This finding provides a new alternative strategy for the treatment of UC. However, owing to the limitations of the evidence provided by the included SRs/MAs, this conclusion must be treated with caution. [ABSTRACT FROM AUTHOR]

Objectives. Gegen Qinlian decoction (GQD), a Chinese herbal compound, has been widely used in the treatment of ulcerative colitis (UC) in China. However, evidence from systematic reviews (SRs)/meta-analyses (MAs) of GQD in UC remains highly controversial. To collate, evaluate, and synthesize the current evidence, we carried out this study. Methods. SRs/MAs of GQD for UC were obtained from eight databases. Methodological Quality of Systematic Reviews 2 (AMSTAR-2) was utilized to appraise the methodological quality, Preferred Reporting Item for Systematic Reviews and Meta-Analyses (PRISMA) for reporting quality, and Grading of Recommendations Assessment, Development, and Evaluation (GRADE) for evidence quality. Results. Four eligible SRs/MAs were obtained. According to AMSTAR 2, all SRs/MAs were graded as critically low quality. According to PRISMA checklist, all SRs/MAs failed to report the information of protocol and registration. With GRADE, no outcome measure with high-quality evidence was found, and the evidence quality for outcome measures was in the moderate to critically low levels. Conclusions. GQD with conventional medicine (CM) seems to be more effective in UC than CM alone. This finding provides a new alternative strategy for the treatment of UC. However, owing to the limitations of the evidence provided by the included SRs/MAs, this conclusion must be treated with caution. [ABSTRACT FROM AUTHOR]

Objectives. Helicobacter pylori (H. pylori) immunoglobulin G (IgG) seropositivity is prevalent, but its correlation with homocysteine (Hcy), a biomarker of vascular risk events, is unclear. This study is aimed at exploring the correlation of H. pylori IgG seropositivity and plasma Hcy levels in adults. Methods. Data was obtained from the National Health and Nutrition Examination Survey (NHANES) cycle 1999-2000. Hcy was measured by the Abbott homocysteine assay, and H. pylori IgG was measured by enzyme-linked immunosorbent assays. The weighted multiple logistic regression analyses with adjustments for potential confounders were conducted. Subgroup analyses stratified by gender, age, and race were performed. Results. A total of 4029 subjects aged 20-85 years were included. Population prevalence of H. pylori IgG seropositivity was 44.7% in the overall population with higher prevalence found in those with older age, Mexican Americans, lower education, and lower household income. Levels of plasma Hcy were not elevated in those with H. pylori IgG seropositivity versus seronegativity (β -0.120 (-0.438, 0.199) P = 0.462). This difference was not significant after stratifying by gender and age. However, in the subgroup analyses stratified by race, a negative correlation between H. pylori seropositivity and plasma Hcy levels was observed in Mexican Americans (β -0.802 (-1.253, -0.352) P < 0.001). Conclusions. H. pylori IgG seropositivity was not associated with plasma Hcy levels in the general population, but there may be a negative correlation in Mexican Americans. These findings provide new insights to advance the research of the link between plasma Hcy levels and stomach health. [ABSTRACT FROM AUTHOR]

In tunnel heating systems, phase change materials may minimize the consumption of conventional electric energy, which is very considerate in the field of tunnel heating in cold regions. Because of the phase change material's poor heat conductivity, its annual growth rate heat absorption and release is slower; thus, the majority of phase change heat storage systems must improve heat transmission. In this study, a spiral metal ring is implanted in the paraffin to improve heat transmission to achieve this objective using a concentric sleeve-type paraffin heat storage device as a medium. Experiments were performed out in order to determine the effects of heating rate, hot fluid flow rate, and the use of a spiral metal ring on the heat storage and release process of a thermal storage device. In comparison to the paraffin thermal storage device, the embedding of the spiral metal ring accelerates the internal thermal performance of the composite heat storage device, resulting in a more uniform temperature distribution. When the thermal radiation heating rate is 60°C, 65°C, or 70°C during the heat storage process, the heat storage time of the composite heating storage device is reduced by 59.2 percent, 44.4 percent, and 40.7 percent, respectively. When the ambient temperature is 26°C and the heat storage device's starting temperature is 65°C, the exothermic time is reduced by 22.6 percent. [ABSTRACT FROM AUTHOR]

For tunnels in cold or serious cold areas, the problem of leaking in the spring thawing period is very frequent, which will cause various tunnel diseases due to freezing. By using the surrounding rock geothermal energy in the tunnel project, especially the tunnel project below the permafrost layer, the cold area tunnel heat pump system is able to improve the overall heating energy efficiency as the side temperature regarding the heat pump evaporation increases, that furtherly serves the surrounding supporting building facilities. Inspired by this system and the active and passive coupling building technology, a heat recovery type of heat storage wall model is proposed in this research. By describing the heat transfer process regarding the heat recovery type of heat storage wall and carrying out the experimental research, its feasibility and effectiveness are verified. The results show that when the outdoor ambient temperature in Urumqi is −7~−15°C and the instantaneous total solar radiation reaches the range of 0~1108 W/m2, this kind of wall can create hot wall-near air whose temperature is 11.89°C higher than the ambient temperature for providing a high-quality air heat source for the air source heat pump when the temperature is low, thereby significantly improving the air source heat pump heating system efficiency. Without the photovoltaic and photothermal equipment, the heat recovery type of heat storage wall can make the utilization rate of solar energy reach 13% to 20%, even up to 36%. [ABSTRACT FROM AUTHOR]

Although numerous studies have attempted to use vehicle motion data for real-time vehicle crash prediction, many driver behavior and road/environment factors (e.g., driving intention and pavement condition) have not been considered. In order to cope with increased complexity and extent crash risk assessment with the consideration of factors like driving intention and pavement condition, this paper (a) combines driver intention, vehicle motion, and dynamic traffic environment into the assessment of the conflict risk in real time, (b) establishes a hierarchical analysis model for quantitatively describing driving safety based on an Analytic Hierarchy Process (AHP), and (c) applies a Matter Element (ME) Model to take multiple factors, which are heterogeneous in terms of nature of analysis (quantitative or qualitative) and measure units, into account, and provide a comprehensive evaluation of vehicle crash risk. Finally, a set of simulation cases are used to compare the detection efficiency of the proposed method with ANN and SVM for vehicle collision. The example analysis shows that the proposed AHP-ME model can more accurately predict the collision risk of vehicles. Moreover, the proposed AHP-ME model provides an effective solution to unify multi-factors (driver intention, vehicle motion, and dynamic traffic environment) into an integrated decision-making framework. [ABSTRACT FROM AUTHOR]

Objective. To research the mechanism of action and transcriptomic characteristics for the intervention effect of self-made Chaihuang decoction (Sichs) on gastric ulcer (GU) rats with liver qi stagnation and spleen deficiency and to clarify the therapeutic pathway and effective target. Methods. Thirty SD rats were randomly divided into the control group, model group, and Sichs group (10 rats per group). The model of GU rats with liver qi stagnation and spleen deficiency was established through multifactor compound simulation of traditional Chinese medical (TCM) etiology and acetic acid method. Histopathological changes in the gastric antrum tissue were observed with H&E staining. RNA sequencing (RNA-seq) was utilized to check differentially expressed genes (DEGs) in the gastric antrum tissues of rats, and gene ontology (GO) and KEGG pathway enrichment analyses were performed. The key DEGs were validated using qRT-PCR. Results. Sichs could ameliorate gastric antrum tissue injury in GU rats with liver qi stagnation and spleen deficiency. After RNA-seq, it was found that Sichs could reverse 225 upregulated genes and 26 downregulated genes in the model group. And the DEGs between the Sichs group and the model group were related to cell division, complement activation, and phospholipase A2 (Pla2g2a) activity. According to KEGG pathway analysis, DEGs between the two groups were mainly enriched in signaling pathways such as cell cycle, p53 signaling pathway, and linolenic acid metabolism. The validation results of the four key DEGs were consistent with the analysis trend of sequencing results. Conclusion. Sichs can effectively improve GU with liver qi stagnation and spleen deficiency in rats through the signaling pathways related to cell cycle and lipid metabolism. [ABSTRACT FROM AUTHOR]

Background. In Traditional Chinese Medicine (TCM), Dahuang Danshen decoction (DD) is used to treat pancreatic fibrosis. Pancreatic fibrosis is a typical manifestation of chronic pancreatitis (CP), which affects the digestive system. The therapeutic mechanisms of DD in pancreatic fibrosis are unclear. Aim. This study aimed to investigate the regulatory mechanisms of DD on oxidative stress and endoplasmic reticulum stress in CP. Materials and Methods. Experimental rats were intraperitoneally injected with 500 mg/kg BW of diethyldithiocarbamate (DDC) twice a week for six weeks to induce CP. At the same time, DD was administered orally at daily doses of 1.37 g/kg BW, 2.74 g/kg BW, and 5.48 g/kg BW to evaluate its treatment effects on CP. After all treatments, pancreatic tissues were harvested and subjected to H&E staining. Transmission electron microscopy (TEM) was also performed to show the endoplasmic reticulum structure in the pancreatic tissues. Immunohistochemistry was used to detect the α-SMA expression level in the pancreatic tissues. Metabolomics analysis of the serum and proteomics analysis of the pancreatic tissues were performed to reveal the changes of endogenous metabolites and proteins, respectively. Concentrations of GSH, MDA, SOD, ROS, col-1, and col-3 were determined using corresponding kits. The western blotting method was used to determine the protein levels of Keap-1, HO-1, NQO1, Nrf2, GRP, JNK, and caspase 12. The pancreatic mRNA levels of NQO1, GPX1, HO-1, GST-π, GRP, JNK, and caspase 12 were also determined by quantitative PCR. The interactions between TCM components and Keap-1 were investigated by molecular docking modeling. Results. The pathohistological results demonstrated that DD could ameliorate DDC-induced CP in vivo, indicated by reduction of α-SMA, col-1, col-3, TNF-α, and IL-6. DD increased serum levels of GSH and SOD but reduced pancreatic ROS. DD decreased cytoplasmic Keap-1 and increased Nrf2 nuclear localization. Correspondingly, DD increased the expression levels of Nrf2 downstream antioxidant genes NQO1, GPX1, HO-1, and GST-π. DD also decreased ERS hallmarks caspase 12 cleavage and GRP expression. Eventually, DD inhibited PSC activation by reducing JNK phosphorylation and MMK-3/p38 expression. Molecular docking analysis showed that salvianolic acid B and emodin had a good binding affinity toward Keap-1. Conclusions. These results demonstrated that DD could ameliorate the oxidative and endoplasmic reticulum stress through releasing Nrf2 from Keap-1 binding and inducing the downstream antioxidant enzymes. As a result, DD could thwart pancreatic fibrosis by inhibiting PSCs activation, which was induced by OS and ERS through JNK and MMK3/p38 pathways. [ABSTRACT FROM AUTHOR]