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The northwestern Qaidam Basin has great potential for natural gas exploration. Research and exploration activities of natural gas conducted over the last two decades have provided abundant information about natural gas geochemistry. However, its genesis, source, and accumulation process are still controversial. This research utilized a published comprehensive natural gas dataset and a 3D basin modeling approach to ascertain the genesis of natural gas in the northwestern Qaidam Basin and to discuss its accumulation process. Moreover, diagrams for classifying the source material type were revised to better understand the origin of natural gas. In the northwestern Qaidam Basin, the source material type of natural gas is chiefly coal-type gas with a few oil-type gases. Natural gases from the Jianshan anticline originated predominantly from the Jurassic source rock, while those in most other regions were derived mainly from the Upper Xiaganchaigou source rocks. However, some oil-associated gas related to oil accumulation came chiefly from the Shangganchaigou source rock. In addition, a small amount of early mature thermogenic gas in the Xiaoliangshan, Yondunzi, and Xianshuiquan regions may have come from the Lower Youshashan source rock. Moreover, this research discovered the secondary cracking gas of oil in the northwestern Qaidam Basin, which has a great significance in broadening the natural gas exploration in an area. Similarly, the gas accumulation models were established for three types of gases, i.e., oil-associated gas, late primary cracking gas, and oil-cracking gas. This study emphasizes geological research based on a comprehensive field dataset analysis and comparing adjacent mature blocks. This methodology can be used in other emerging natural gas exploration areas. [ABSTRACT FROM AUTHOR]

A high time resolution synchronous sampling method al ong with determination of stable carbon isotopes of gaseous water-soluble organic carbon (WSOCg) and particulate water-soluble organic carbon (WSOCp) was realized in this research through equipment modification and method improvement. It was found that WSOCg has significant higher concentration than WSOCp and a more depleted δ13C. Both concentrations of WSOCp and WSOCg have the seasonal variation characteristics of high in winter (WSOCp=15.7±3.9µg/m³; WSOCg=42.4±6.0µg/m³) and low in summer (WSOCp=5.9±1.8µg/m³; WSOCg=25.2±5.2µg/m³), with greater increase in WSOCp (167%) than that in WSOCg (68%). During wintertime, WSOCp and WSOCg had similar daily variation characteristics of concentration, and opposite daily variation characteristics of δ13C. WSOCp had a bimodal distribution with obvious low value at sunrise and sunset, while δ13C WSOCp had a unimodal distribution with low in daytime (-24.6±1.1‰) and high in nighttime (- 22.3±1.7‰). WSOCg and δ13C-WSOCg had same distribution with high in daytime and (49.3±8.8µg/m³; -27.9±1.1‰) low in nighttime (38.3±4.6µg/m³; -29.9±0.4‰). Combining the δ13C variation characteristics with the synchronous observation results of meteorological conditions, gaseous precursor pollutants, gaseous oxidants, gaseous acids and fine particle components, the restriction factors of WSOC gas-particle distribution mechanism were discussed. The presence of radiation rather than its intensity decided whether generations process of WSOCp and WSOCg are divided, for δ13C-WSOC of two phases showed significant correlation only during daytime. Meteorological conditions, gaseous precursor pollutants, gaseous oxidants and gaseous acids restrict the gas particle distribution of WSOC by affecting the aging process of WSOCp and WSOCg, gas particle conversion ratio of semi-volatile organic compounds (SVOC) and the gas phase and liquid phase generation ratio of WSOCp. At the same time, the gas-particle distribution process of WSOC is strongly related to the formation of secondary inorganic ions (nitrate, sulfate, ammonium), and the gas-particle distribution between gaseous nitrous acid and nitrite. [ABSTRACT FROM AUTHOR]

The complexity and diversity of reservoir characteristics, including strong heterogeneity, complex pore structures, distinct pore size distributions, and various fluid occurrences, in different environments lead to differential oil recovery from the Chang 7 reservoir. In this research, several experiments such as nuclear magnetic resonance, high-pressure mercury intrusion, scanning electron microscopy, thin section, and X-ray diffraction were utilized to analyze PSD, heterogeneity, and movable fluid occurrence in the Chang 7 sandstone samples from the Ansai and Heshui Blocks. A 3-stage construction method is proposed to transform the T2 spectrum to pore-throat radius distribution to realize large-scale and continuous PSD characterization. The results indicate that the sandstone in the Heshui Block is mainly feldspar lithic fragment sandstone, while the sandstone in the Ansai Block is mainly lithic fragment feldspar sandstone and feldspar sandstone. The storage spaces in the Chang 7 reservoirs were comprised primarily of nanoscale pores, followed by submicron pores. The Chang 7 reservoirs in different environments differed greatly in PSD, fractal feature, and movable fluid occurrence. Sandstone in the Heshui Block, compared to that in the Ansai Block, had better physical properties generally characterized by more submicron pores, weak heterogeneity, and more movable fluid in submicron pores. The movable fluid occurrence could be affected by various factors such as physical properties, mineral composition, pore size and distribution, and heterogeneity. The influence of these factors on movable fluid distribution varied in reservoirs of different areas. Generally, reservoirs with good physical properties and higher availability of submicron pores are often associated with high movable fluid content. The influence of carbonatite on the movable fluid content in the two areas was opposite. The relationship between the movable fluid content in different pores and pore size parameters varied in different sedimentary environments. The influence of heterogeneity on the movable fluid occurrence in submicron pores was stronger than nanoscale pores in the Heshui Block, while it was the opposite in the Ansai Block. [ABSTRACT FROM AUTHOR]

Background: The benefit of blood cholesterol reduction for secondary prevention of ischemic stroke remains undetermined in Chinese patients. The purpose of this meta-analysis was to determine whether lipid-lowering agents including statins, fibrates, nicotinic acid, and ezetimibe reduced the risk of recurrent stroke in ischemic stroke patients in China and whether such findings could inform treatment decisions for blood lipid-lowering treatment in China. Methods: The English electronic databases PubMed, EMBASE, Cochrane Library and Chinese databases CNKI, Sino-Med, Wan Fang, and VIP were searched for studies published between January 1990 and April 2020. This meta-analysis included published data from trials that randomly assigned patients to groups treated with either blood lipid-lowering regimens or placebo. Effect comparisons were made using fixed effects model in meta-analysis and linear and spline regression were performed to identify the relative risk of stroke recurrence. The primary outcome was the reduction of total ischemic stroke events, and relative risk values were obtained using a risk prediction equation developed from the control groups of the included trials. Results: Five studies including 4,999 individuals with available data met the inclusion criteria. Relative to the control groups, the pooled estimated odds ratio (OR) for recurrent stroke among those who received lipid-lowering therapy was 0.79 (95% confidence interval [CI]: 0.63–1.00). A 50% or greater reduction in low-density lipoprotein cholesterol (LDL-C) significantly reduced the risk of ischemic stroke recurrence (OR: 0.15 [95% CI: 0.11–0.20]). The overall beneficial effect of statin therapy was confirmed to prevent ischemic stroke with an OR of 0.51 (95% CI: 0.36–0.72). Conclusions: Effective lipid-lowering therapy could decrease the blood LDL-C level, which had a protective effect against stroke recurrence. These results support the use of predicted baseline cerebrovascular disease risk equations to inform decisions regarding blood lipid-lowering treatment in ischemic stroke patients in China. [ABSTRACT FROM AUTHOR]

Summary: Background: In China, the prevalence of superficial fungal infections of the foot is high and recurrence is common. However, a prospective, large‐scale and multicentre study on the aetiology of superficial fungal infections of the foot is still lacking. Objectives: To study the epidemiology of aetiological agents of superficial fungal infections of the foot in urban outpatients in mainland China, as well as to understand the aetiology features of the pathogenic agent. Methods: The study was designed as a multicentre, prospective epidemiological survey. A total of 1704 subjects were enrolled from seven geographical areas in mainland China. For each subject, one mycological sample and one bacterial sample were collected. KOH wet mount examination and culture were performed at local laboratories. The bacterial results were only reported in those with positive mycology. Further morphological identification and, if necessary, molecular biological identification were conducted in a central laboratory. Results: Of 1704 enrolled subjects, 1327 (77.9%) subjects had positive fungal culture results. The incidence of dermatophytes, yeasts and moulds was 90.1%, 8.1% and 1.1%, respectively. The most frequently isolated aetiological agent (fungus) was Trichophyton rubrum. Moccasin form was the most commonly reported clinical diagnosis of superficial fungal infections. The most frequently isolated bacterial genus in patients was Staphylococcus. Conclusion: This study prospectively investigated the clinical and mycological features of human dermatophytosis in mainland China. T rubrum was the most frequently isolated fungus, and moccasin form was the most commonly reported clinical diagnosis of superficial fungal infections. [ABSTRACT FROM AUTHOR]

Unexploited land change is a main driver of regional eco-environment change. Through an integrated technique of geographic information system (GIS), remote sensing (RS), and global positioning system (GPS), the authors attempted to address this topic by examining unexploited land conversion in Guiyang City in Guizhou province in southwestern China as a case study, as well as looking at the effect of policies in land use from 1996 to 2010 in the same area. Results showed that: Agricultural development of unexploited land was encouraged from 1996 to 2000, and a progression conversion process with direct and indirect transformations overlaid was formed by unexploited land → arable land + unexploited land → forest land and grass land → arable land. The conversion management of unexploited land was enhanced, unexploited land occupied for construction was controlled, and the area of unexploited land converted to forest land and grassland showed an upward trend from 2000 to 2006. Local government was encouraged and supported in exploring construction and use of unexploited land, and achieved the maximum value by converting unexploited land to construction land, as a result we see the area of forest land and grassland decreased from 2006 to 2010. [ABSTRACT FROM AUTHOR]

Purposes Very few data for polybrominated diphenyl ethers (PBDEs) were available in the Yangtze River Delta (YRD), one of the most developed and urbanized region in China. In this study, Chongming Island, located at the estuary of the Yangtze River, was selected as background area to investigate the occurrence, sources, and inventory of PBDEs. Methods Forty-two PBDE congeners were determined in surface soils from farmland, woodland, grassland, tideland, and road collected in Chongming Island. Results The mean concentrations of ∑26PBDE (not including BDE-209) and BDE-209 in soils were 0.76 and 12 ng/g dry weight, respectively. BDE-209 contributed more than 90% of the total of 27 frequently detected BDE congeners, followed by BDE-99 and BDE-47. Weak correlations were found between total organic carbon content and PBDE congeners concentrations in surface soils. PBDE levels varied with land use. Farmland and woodland soils contained higher ∑26PBDE concentrations. BDE-209 levels were the highest in road soils. The mass inventories of PBDEs in soils of Chongming Island were estimated at 3.1 and 310 kg for ∑26PBDEs and BDE-209, respectively. Conclusions The PBDE levels in Chongming Island were similar to those in European background soils, suggesting minimum influence of pollutants from the YRD via air, and wastewater inputs or few PBDE products were used herein. From the standpoint of eco-inland, more studies are needed to explore the reasons of PBDE difference by land use and to assess people intake PBDEs via agriculture products consumption in this region. [ABSTRACT FROM AUTHOR]

To analyze the TCM health culture level and influence factors of Chinese citizens in 2017. PPS sampling combined with random sampling was used to select the residents aged between 15-69 years old in 30 provinces as the respondents,and a questionnaire study was conducted to investigate their TCM health culture level. In 2017,there were 87 287 valid questionnaires for Chinese citizens' TCM health culture level,including 48. 25% male and 51. 75% female,with a sex ratio of 1 ∶ 1. 073. In 2017,the overall TCM health culture level was 13. 39%,specifically 18. 77% for the urban areas and 10. 51% for the rural areas. Compared with people who were illiterate or less literate,people with an educational background of elementary school,junior high school,high school/vocational/technical school and junior college/university had a higher TCM health culture level,and the OR values were 1. 584( 95% CI[1. 166,2. 152]),2. 827( 95%CI[1. 839,4. 345]),5. 651( 95%CI[3. 637,8. 781]),9. 785( 95%CI[6. 187,15. 477]) in order. With civil servants as the reference,medical workers had a higher TCM health culture level( OR = 1. 829,95%CI[1. 279,2. 616]),while farmers had the lowest TCM health culture level( OR = 0. 493,95% CI[0. 349,0. 697]). Compared with people with the annual household income per capita of 20 000 yuan and below,people with the annual household income per capita between 20 000-50 000,50 000-80 000,80 000 yuan or above had a higher TCM health culture level,and the OR values were 1. 176( 95% CI[0. 963,1. 437]),1. 458( 95%CI[1. 168,1. 820]) and 1. 930( 95%CI[1. 509,2. 469]). Based on the differences between urban and rural areas,the influence factors of citizens' TCM health culture level include education,occupation and income.