Geochemical evidence for in situ accumulation of tight gas in the Xujiahe Formation coal measures in the central Sichuan Basin, China

The study of accumulation mechanisms of tight gas has attracted much attention in recent years. One of the focuses is whether natural gas can migrate on a large scale in tight reservoirs. In this work, geochemical parameters (such as C1/C1+, C1/(C2+ C3), C1+, δ13C1, δ13C2, iC4/nC4, iC5/nC5) of the tight gas reservoirs in the central Sichuan Basin, China have been studied to characterize the accumulation mechanisms in these fields. Results show that the tight gas accumulation in the Xujiahe Formation in the central Sichuan is in situ, and natural gas has not experienced large-scale migration. In gases from the central Sichuan Basin, δ13C1 ranges from −44.1‰ to −37.1‰ with an average of −40.1‰, and C1/C1+ ranges from 0.80 to 0.97 with an average of 0.91. While in the gases from the western Sichuan Basin, δ13C1 is between −35.5‰ and − 30‰ with an average of −32.2‰, and C1/C1+ ranges from 0.95to 0.99with an average of 0.98. Based on geochemical indicators of natural gas, the gases of Xujiahe Formation in the Central Sichuan Basin originated from the local coal measures of the Xujiahe Formation in horizontal direction with little contribution from the western Sichuan. In central Sichuan Basin, there is also no horizontal migration of natural gas in the same formation between adjacent gas fields. Vertically, the Xujiahe Formation is an independent gas generating system and has no relationship with the underlying Mid-Lower Triassic formations and the Jurassic natural gas formation above it. The δ13C2of Xujiahe Formation in central Sichuan ranges from −28.3‰ to −25.9‰, with an average of −27.5‰. However, the δ13C2 of Lower Jurassic above Xujiahe Formation ranges from −36.8‰ to −30.5‰, with an average of −33.0‰. Under the Xujiahe Formation, the δ13C2 in Leikoupo Formation ranges from −35.5‰ to −32.1‰, with an average of −33.1‰, and in Jialingjiang Formation ranges from −34.6‰ to −33.2‰, with an average of −33.8‰. There is also a clear distinction in the geochemical characteristics of natural gas between the upper and lower gas reservoirs in the Xujiahe Formation, indicating that there is no obvious vertical migration of natural gas. Geochemical evidence shows that there is no large-scale gas migration in the Xujiahe Formation. The tight gas is generated in situ and accumulated in the formation in the central Sichuan Basin

Fine mapping of growth-related quantitative trait loci in Yellow River carp (Cyprinus carpio haematoperus)

Genetic linkage map and quantitative trait loci (QTL) mapping are powerful tools for genetic analysis of a series of economic traits in aquatic animals. Yellow River carp (Cyprinus carpio haematoperus), one of the famous common carp strains, is widely cultured in northern China, however, genetic and genomic bases of growth-related traits have been rarely studied in this carp strain. In present study, an F2 family of Yellow River carp (8 months old) was used for constructing genetic linkage map and detecting potential QTL for growth traits, including total length (TL), body length (BL), body height (BH), head length (HL) and body weight (BW). A high-density genetic linkage map was constructed mainly based on 2b-RAD technology, with 6230 SNPs and 65 SSRs assigned onto 50 linkage groups, covering 98.2% of the Yellow River carp genome (average 0.59 cM/marker). Comparative mapping showed high levels of syntenic relationship between our map and the genomes of two cyprinid fish (Denio rerio and Ctenopharyngodon idellus), while a lower synteny was detected between our map and C. c. carpio genome. Twelve chromosome-wide and two genome-wide growth-associated QTL were detected in our study, with the phenotypic variance explained ranging from 11.9% to 16.2%. These QTL were scatteredly distributed on 8 LGs of our sex-averaged linkage map. Fifteen candidate genes (e.g. INSIG1, 3 beta-HSD, HGF) were identified by BLAST searching the sequences of QTL-linked markers in Yellow River carp against Denio rerio genome, and their functions involve in the regulation of development, cell-proliferation, energy metabolism, and so on. The identification of significant QTL and potential growth-related genes in this study provides valuable genomic resources for the study of genetic mechanism underlying growth and development, and would contribute to accelerate the progress of marker-assisted selection in Yellow River carp

Significant Improvement of Anticorrosion Properties of Zinc-Containing Coating Using Sodium Polystyrene Sulfonate Noncovalent Modified Graphene Dispersions

High-quality graphene zinc-containing anticorrosive coatings are highly and urgently desirable for effective, economical anticorrosion of metals and alloys in industrial products. The realization of such coatings is, however, hindered by the dispersibility and compatibility of the graphene in them. This work reports a novel direct modification of graphene using sodium polystyrene sulfonate (PSS) without reduction of graphene oxide, leading to homogeneous dispersion of graphene in water. The agglomeration of graphene is prevented thanks to the formation of π−π interaction between PSS and graphene sheets. Such graphene dispersion can effectively improve the anticorrosion performance of the zinc-containing epoxy coatings. With the addition of graphene modified by PSS into the 20% zinc-containing epoxy coating (graphene is 0.05% by weight of the coating), its anticorrosion properties revealed by both electrochemical characterization and the neutral salt spray tolerance analysis are rather close to those of 60% zinc-containing epoxy coating. These results demonstrate that direct PSS modification is an effective method for graphene dispersion and thus open a pathway to achieve graphene zinc-containing anticorrosive coatings with high performance

Enhanced Anti-Corrosion Performances of Epoxy Resin Using the Addition of Sodium Dodecylbenzene Sulfonate-Modified Graphene

The improvement of anti-corrosive property of epoxy resin is significant for the development of coatings to avoid metal corrosion and thus to reduce the economic loss in many industries. The superior properties of graphene, a two-dimensional material, make it possibly suitable to fulfill this task. However, this is hindered by the easy agglomeration of graphene layers in solvents. In the present work, we report the modification and stabilization of graphene in water using sodium dodecylbenzene sulfonate (SDBS) and the enhancement of the anti-corrosive properties of epoxy resin by mixing such SDBS-modified graphene layers. The influence of the dosage of SDBS on the modification effect of graphene was studied in detail and an optimized dosage, i.e., 50 mg SDBS for 10 mg graphene, was obtained. The SDBS modification could effectively reduce graphene thickness, and the minimum thickness of the modified graphene was 3.50 nm. The modified graphene had increased layer spacing, and the maximum layer spacing was 0.426 nm. When the modified graphene was added into the epoxy resin, the electrochemical impedance modulus value evidently increased compared to pure epoxy resin and those incorporated by pure graphene, indicating that the anti-corrosion performance was significantly improved. These results clarified that SDBS could effectively modify graphene and the SDBS-modified graphene could subsequently largely improve the anti-corrosive property of epoxy resin, which is of significance for the anti-corrosive coatings

Sex-Specific Association of Serum Uric Acid Level and Change in Hyperuricemia Status with Risk of Type 2 Diabetes Mellitus: A Large Cohort Study in China

Background. Conflicting findings have been reported regarding the sex-specific association between serum uric acid (SUA) level and type 2 diabetes mellitus (T2DM) risk, and no study has explored the association between the change in hyperuricemia status and T2DM risk. The study was aimed at exploring the sex-specific association of baseline SUA and changes in hyperuricemia status with T2DM risk. Methods. We included 37,296 eligible adults without T2DM at the first examination who attended the baseline examination and at least one follow-up annual examination. Cox and logistic regression models were used to calculate hazard ratios (HRs) and odds ratios (ORs) with their 95% confidence intervals (CIs) for T2DM risk associated with baseline SUA and the change in hyperuricemia status, respectively. Results. During a median follow-up of 3.09 years, of 37,296 eligible adults, 2,263 developed T2DM. Compared with the first SUA quartile, higher quartiles were associated with an increased risk of T2DM in women (HR 1.78, 95% CI 1.17-2.71 for Q3 and 1.93, 1.27-2.93 for Q4; Ptrend<0.001) but not in men. Compared with women with a persistent normal SUA level at baseline and the last follow-up, T2DM risk increased significantly among those whose SUA status changed from normal at baseline to hyperuricemia at the last follow-up (OR 1.71, 95% CI 1.12-2.55) and those with persistent hyperuricemia at baseline and the last follow-up (OR 2.37, 95% CI 1.60-3.46). However, for men, a nonsignificant association was found between the change in hyperuricemia status and T2DM risk. Conclusions. Baseline SUA and the change in hyperuricemia status were associated with T2DM risk only among women. The findings suggest the importance of monitoring SUA levels and maintaining them within a normal range for preventing or reducing incident T2DM in Chinese women