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To investigate the evolution of coal permeability during the process of gas pressure change, four different forms of permeability models were derived based on the correlation between mesoscale parameters of coal representative elementary volume (REV) and strain-related characteristics. The reliability of the models was verified using experimental data, and the variation law of strain caused by effective stress and adsorption strain was analyzed and compared with classical permeability models (P-M model, S-D model, Connell model). The sensitivity of model parameters was discussed, the relationship between REV mesoscale parameters and fracture porosity and permeability was clarified, and the influence mechanism of adsorption strain coefficient was analyzed. Furthermore, the extreme values of permeability of major coal mines in China were studied. Results show that for the four permeability models derived in this paper, the REV volume strain satisfies a linear relationship with its fracture volume strain, and the correlation coefficient is the initial fracture porosity. The bulk modulus and adsorption strain coefficient control the influence of effective stress and adsorption strain on permeability, respectively. Under three different experimental conditions of constant confining pressure, constant pore pressure, and constant differential pressure, the four permeability models have shown a better matching effect on the experimental data compared with the classical permeability models. However, compared with single-parameter fitting, the parameter error in the double-parameter fitting (bulk modulus and adsorption strain coefficient) is larger. From the sensitivity analysis of parameters, it is observed that when the parameters change within 10%, the predicted permeability deviates significantly from the true value. Therefore, for the double or multiple-parameter fitting of permeability models, the parameter fitting errors could lead to serious distortion of the predicted permeability results. Taking the experimental data of coal samples from the Qinshui Basin as an example, the mesoscopic scale parameters a0 and b0 of REV were calculated to range from 1.73 to 46.31 μm and from 0.06 to 0.49 μm, respectively. Under constant confining pressure and constant differential pressure conditions, the adsorption strain coefficient was related to differential pressure, gas types, and initial fracture porosity. Furthermore, the extreme values of CO2 gas and CH4 gas in major coal mines in China are within the ranges of 0.94−5.33 MPa and 1.06−6.94 MPa, respectively.

The in vitro models of lysophosphatidylcholine 18:1 (LPC(18:1)), lysophosphatidy- lethanolamine 18:1 (LPE(18:1)) and oleic acid were constructed by simulating the pH, LPC(18:1) and LPE(18:1) contents and steaming conditions of Chinese water chestnut (CWC). The content of nonanal, decanal and oleic acid, and peroxide value (POV) produced by the in vitro models were used as indicators to investigate the formation mechanism of nonanal and decanal from LPC(18:1) and LPE(18:1) during the steaming of CWC. The results showed that the possible mechanism of the oxidation of LPC(18:1) and LPE(18:1) to form nonanal and decanal was as follows. First of all, the C8 and C11 positions close to the double bond on the unsaturated acyl chain of LPC(18:1) and LPE(18:1) lost H respectively, and then formed R·. In the second step, the R· directly reacted with O2 and H to form 8-hydroperoxide (8-ROOH), or reacted with O2 and H to form 9-hydroperoxide (9-ROOH) and 10-hydroperoxide (10-ROOH) after electron rearrangement. Finally, 8-ROOH split homogeneously to form decanal, 9-ROOH and 10-ROOH split homogeneously to form nonanal. The results can provide scientific reference for the formation mechanism of flavor substances and the regulation of flavor quality of fruits and vegetables.

Objective To compare the effectiveness of the old mode of blood isolation and batch release (the old mode) and the new mode in Chengdu, so as to provide basis for optimizing working strategy. Methods 1) The blood testing report was released one by one in the old mode but released uniformly in accordance with the blood batches classified by blood storage and supply department in the new mode. 2) In the old mode, apheresis platelet samples were detected by serological testing first and nucleic acid testing(NAT) later, and whole blood samples were reasonably arranged according to blood inventory and detection workload. In the new mode, platelets samples collected within our center headquarters were detected by serological test and NAT simultaneously, while those collected outside the center complied with the old strategy. As for whole blood, the same batch samples classified by blood storage and supply department should be arranged to the detection line with the fewest samples.3) The turnaround time(TAT) in the laboratory (referred to as sample TAT) and the TAT in the blood to-detect stock (referred to as blood TAT) in two phases(year 2016 vs 2018, pre- and post- the new mode), involving 164 748 and 179 488 blood samples, were compared by SPSS25.0 software. The constituent ratio of the TATs were compared with Chi-square test, and the difference of blood TAT between old and new mode were compared with Mann-Whitney U test. Results 1) Significant difference was noticed in constituent ratio of TATs between old and new mode (P

Although the current developed Blu-ray disc-based technology could realize digitized molecular detection, the result analysis of which depends on computer, not applicable for on-site applications. In order to overcome the above challenges, we herein report a quantitative detection system developed by the embedded technology. In particular, through the transplantation of embedded systems and disc quality diagnosis software, and the development of data processing programs, this system realizes the automatic analysis of bio-discs with this integrated device. It has been utilized for the detection of printed ink dots and the biotin-streptavidin binding reaction on BD surface, preving the reliability and feasibility for biomolecular detection.

Detection of uric acid is crucial for real-time monitoring of human health. In this work, a method of portable scanner-based quantitative detection of uric acid with a smartphone was developed, meanwhile, a filter paper chip was designed and fabricated for the detection process, which provides an on-site, fast, and accurate measurement of the uric acid in human blood serum. The limit of detection was 0.8 mg/dL, and the detection results of human serum samples showed good agreement between the spectrophotometric method and the proposed one. This method does not require complex operations or expensive instruments, which is suitable for resource-limited areas, users’ home, as well as on-site detection, with wide applications and broad market prospects.

The structures and properties of the composite films formed by soy protein isolate (SPI) and xanthan gum (XG) with different other matrices were investigated. The composite films were prepared with SPI and XG by adding sodium alginate (SA), carboxymethyl cellulose (CMC), gelatin (GEL), pectin (PEC) and agar (Agar), respectively. The thickness, mechanical properties, oxygen permeability and opacity of the composite films were measured, and their structures were characterized. The results showed that the thicknesses of composite films with 1.5 g of different other matrices were significantly higher (P

Objective To study the distribution and trend of HIV-1 drug resistance mutation in Dalian blood donors between 2011 and 2020. Methods The protease-reverse transcriptase (PR-RT) region was sequenced in Dalian blood donors tested HIV-1 positive between 2011 and 2020. Drug resistance mutation (DRM) rate and level of resistance to selected drugs were analyzed by the Stanford HIV Drug Resistance Database. Results DRM were detected in 17.2% (30/174) of samples, while transmitted drug resistance (TDR) was 5.7% (10/174). Between 2011 and 2020, DRM and TDR rates increased significantly in 2019 and reached their highest levels in 2020 (44.4% and 22.2%, respectively). DRM carriage was associated with people with college degree or above and with local residents (P

Atopic dermatitis (AD) is a chronic inflammatory skin disease with the highest disease burden among non-fatal dermatoses. Severe itching and frequent recurrence seriously affect the patients′ psychological and social functions, resulting in a significant decline in the patients′ quality of life. Using effective measurement instrument to assess the quality of life is an effective way to evaluate the quality of life of AD patients, and to improve patients′ care experience and the clinical outcomes. Here, we review the patient-reported quality-of-life measurement instruments, including generic instruments, dermatology-specific instruments, and disease-specific instruments used in AD. The generic instruments can be used to compare the quality of life of patients with AD and non-skin diseases, while the dermatology-specific instruments can be used to compare the quality of life of patients with different skin diseases. Dermatology-specific instruments and disease-specific instruments used in AD may have greater discriminatory power and higher specificity and sensitivity for subtle changes. How to choose the appropriate scale in clinical practice and research depends on the research question and the applicable population.

The unique sensory quality and health effect of Liupao tea are closely related to the participation of microorganisms in the pile-fermentation process. In order to explore the diversity and distribution of fungi in Liupao tea samples during the pile-fermentation and autoclaved process, traditional isolation and culture method and molecular biological identification technology were used to isolate and identify fungi from 14 samples including the Liupao raw tea, the samples of pile-fermentation process and those of autoclaved process in this study. The results were as follows: 13 genera and 39 species fungi were isolated and identified from the samples. Among them, 23 fungi were reported firstly in Liupao tea, including 3 species of golden flower fungi and 6 species of yeasts. Aspergillus and Penicillium were the dominant fungi genera in Liupao raw tea and the samples of pile-fermentation process. Only Aspergillus niger, Aspergillus sydowii, Penicillium laeve and Penicillium gerundense could be isolated from the samples after autoclaved, and other Aspergillus and Penicillium fungi were almost undetectable. Talaromyces was the dominant genus in the samples of autoclaved process. In terms of species, Aspergillus niger and Arxula adeninivorans were the dominant fungal in all tea samples. The results would enrich the cognition of fungal diversity during the processing of Liupao tea, and provide the material basis and theoretical basis for further exploring the effects of different tea source fungi on the quality of Liupao tea.

Objective To investigate the prevalence of hepatitis D virus in Dalian blood donors. Methods The samples reactive to HBV in blood screening were selected with the following confirmed results: 1)HBsAg+ &HBV DNA+ ; 2)HBsAg+ & HBV DNA-; 3)HBsAg-&HBV DNA+ ; 4)NAT-yield uncertain. Qualified samples in routine blood screening were additionally tested with anti-HBc+ and anti-HBs+. All samples selected were tested HDV IgG further. Initial reactive samples would be tested by another HDV IgG assay and HDV IgM assay. HDV IgG positive was confirmed when samples were reactive to two HDV IgG assays. Results None HDV antibodies were detected among 1 344 unqualified samples (507 HBsAg+ &HBV DNA+, 33 HBsAg+ &HBV DNA-, 477 HBsAg-&HBV DNA+ and 327 NAT-yield uncertain samples) or 766 qualified samples (397 anti-HBc+ and 369 anti-HBs samples) in blood screening. Conclusion The prevalence of HDV infections among Dalian blood donors eligible in pre-donation screening seemed extremely low. However, for areas with high HBV prevalence, the risk of blood safety caused by OBI co-infection with HDV should not be ignored.

Objective To investigate HIV-1 subtype distribution and trend among Dalian blood donors between 2011 and 2020, in order to provide information to improve blood safety and HIV prevention. Methods HIV RNA was purified from plasma samples of Dalian blood donors with confirmed HIV infection, which were collected between 2011 and 2020. The HIV pol gene was amplified and sequenced. HIV-1 subtypes were determined by phylogenetic analysis. Results HIV RNA was successfully genotyped in 174 samples from HIV-infected donors. The main subtypes among Dalian blood donors were CRF01_AE(69.5%), CRF07_BC(17.2%), B(5.2%), CRF02_AG(2.9%), C(1.1%), CRF55_01B(1.1%), CRF08_BC(0.6%), CRF59_01B(0.6%) and CRF79_0107(0.6%). There were still 2 cases (1.1%) unclassified. Significant difference was observed when comparing with the published national data. The prevalence of CRF01_AE strains decreased over the years, while CRF07_BC increased significantly. CRF02_AG carriers differed from donors infected with other HIV subtypes by being mostly females (40.0% vs. 2.4%), aged (median: 35y vs. 26y) and lower educational background(junior school degree or below). And 96.7% of local CRF01_AE cases were related to HIV strains, which were reported to circulate in Northeast China and in the MSM population. Conclusion HIV-1 among Dalian blood donors had unique molecular epidemiology and the trends of 07_BC increasing and 01_AE decreasing lagged behind the overall national data. Donor education on blood safety and consultation services to high risk group before donation still need improvement.

Objective To investigate the serological and molecular characteristics of HBsAg+ /HBV DNA non-reactive (NR) infections. Methods Samples tested as HBsAg+ and HBV DNA NR were confirmed by individual NAT repeat testing, viral particle concentration by PEG precipitation combined with in-house nested PCR and real-time quantitative PCR, anti-HBc testing, and HBsAg quantification. HBV sequences were compared with those from donors with chronic and occult infection as controls. Results A total of 792 195 samples were screened between January 2011 and December 2020, of which 53 (1: 14 947) were confirmed HBsAg+ /HBV DNA NR. HBV DNA was detected further in five (9.4%) samples; three S sequences and four Pre Core/Core sequences were obtained. Unique amino acid substitutions (P130T, P135Q/S, R151Q, G153S and S155F) were found in the Core protein that may affect virus packaging and replication. Conclusion Extremely low HBV DNA level was detected in plasmas of HBsAg+ /HBV DNA NR donors. Barely detectable HBV DNA might be associated with unusual mutations in the Pre Core/Core protein affecting viral replication. More sensitive HBV DNA and/or HBsAg assays may be considered to further reduce the potential HBV transfusion-transmission residual risk.

This study investigated the changes of the sensory qualities of appearance, color, aroma, taste, leaf bottom and the chemical components of tea polyphenols, free amino acids, soluble sugar, caffeine, flavonoids, theabrownin (TB), theaflavin (TF) and thearubigin (TR) using the Liupao tea during processing and was produced by group species Zhongcha Tea Factory in Cangwu County, Wuzhou City, Guangxi, China. In addition, the chemical composition, and the antioxidant of the theabrownin (TB) that extracted from the Liupao tea were investigated. The results showed that the contents of water extract, tea polyphenols, thearubigin (TR), free amino acids and flavonoids were significantly decreased during the fermentation process (P40 d>60 d>20 d. The results of this study would provide a theoretical basis for the production and processing of Liupao tea.