Abstract Purpose Measuring lipid composition provides more information than just total lipid content. Hence, the non‐invasive measurement of unsaturated lipid protons with both high efficiency and precision is of pressing need. This study was to optimize echo time (TE) for the best resolving of J‐difference editing of unsaturated lipid resonances. Methods The TE dependence of J‐difference‐edited (JDE) MRS was verified in the density‐matrix simulation, soybean oil phantom, in‐vivo experiments of white adipose tissue (WAT), and skeletal muscles using single‐voxel MEGA‐PRESS sequence at 3T. The peak SNRs and Cramér‐Rao lower bounds (CRLBs) acquired at the proposed TE of 45 ms and previously published TE of 70 ms were compared (eight pairs) in WAT, extramyocelluar lipids (EMCLs), and intramyocellular lipids (IMCLs). The lipid composition in skeletal muscles was compared between healthy males ( n = 7) and females ( n = 7). Results The optimal TE was suggested as 45 ms. Compared to 70 ms, the mean signal gains at TE of 45 ms were 151% in WAT, 168% in EMCL, 204% in IMCL for allylic resonance, and 52% in EMCL for diallylic resonance. CRLBs were significantly reduced at TE of 45 ms in WAT, EMCL, IMCL for allylic resonance and in EMCL for diallylic resonance. With TE of 45 ms, significant gender differences were found in the lipid composition in EMCL pools, while no difference in IMCL pools. Conclusion The JDE‐MRS protocol with TE of 45 ms allows improved quantification of unsaturated lipid resonances in vivo and future lipid metabolism investigations.
A new method to determine Cu,Pb,Cd in atmospheric meteoric water by GAAS is reported.The acidized atmospheric meteoric water samples can be analyzed for the concentration of Cu,Pb and Cd by GAAS.The detection limits for the concentrations of Cu,Pb and Cd are in the range from 0.18pg to 1.12pg,the RSD is less than 2.5% with the recoveries in the range of 100.8% and 106.0%.The proposed method is simple,rapid and accurate.It has been applied to the mass analyses of meteoric water samples from coastal regions of yellow sea and the east china sea with satisfactory results.
Abstract The equine foetal ovary has some unique characteristics that differ from other animals, such as ovary hyperplasia and high oestrogen secretion, and inverted location of cortex and medulla present in adult mare. The ovarian cortex supports the process of folliculogenesis and development, the synthetics and expression of oestrogen; however, the character‐related molecular mechanisms and specific biological functions in equine foetal ovarian cortex are still poorly understood. To explore the associated regulatory networks and molecular events of equine foetal ovary during the hyperplasia stage, we analysed the transcriptomic differences between the equine second‐trimester foetal ovarian cortex and adult ovarian cortex by RNA‐seq. There were 6334 differentially expressed genes (DEGs) present in foetal vs. adult, of which 3234 and 3100 DEGs were upregulated and downregulated, respectively. GO and KEGG were used for functional and pathway enrichment analysis of the DEGs. In particular, we found that some DEGs with high fold changes were related to steroid production and metabolism, such as CYP11A1 , CYP17A1 , LDLR , STAR and SCARB1 , which were in line with the efficient oestrogen production in the equine foetal ovary. The transcriptome profile revealed the functional and developmental characteristics and gene expression patten of the ovarian cortex in the foetal and adult stages of the mare. Our study provides new insights into the molecular mechanism of equine second‐trimester foetal ovarian development through transcriptome analysis and provides insights for improving care or treatment for the pregnant mare and the foetus.
Abstract. In order to better understand the molecular composition and sources of organic aerosols in Tianjin, a coastal megacity in North China, ambient fine aerosol (PM2.5) samples were collected on a day/night basis during November–December 2016 and May–June 2017. Organic molecular compositions in PM2.5, including aliphatic lipids (n-alkanes, fatty acids and fatty alcohols), sugar compounds and photooxidation products from isoprene, monoterpene, β-caryophyllene, naphthalene and toluene, were analysed using gas chromatography-mass spectrometry. Fatty acids, fatty alcohols and saccharides were identified as the most abundant organic compound classes among all the tracers during both seasons. High concentrations of most organics at night in winter may be attributed to intensive residential activities such as house heating and the low boundary layer height. Based on the tracer methods, the contributions of the sum of primary and secondary organic carbon (POC and SOC) to aerosol organic carbon (OC) were 24.8 % (daytime) versus 27.6 % (nighttime) in winter and 38.9 % (daytime) versus 32.5 % (nighttime) in summer. In detail, POC derived from fungal spores, plant debris, and biomass burning accounted for 2.78–31.6 % (12.4 %) of OC in the daytime versus 4.72–45.9 % (16.3 %) at night in winter, and 1.28–9.89 % (5.24 %) versus 2.08–47.2 % (10.6 %) in summer. Biomass burning derived OC was the predominant source of POC in this study, especially at night (16.0 ± 6.88 % in winter and 9.62 ± 8.73 % in summer). Biogenic SOC from isoprene, α/β-pinene and β-caryophyllene exhibited obvious seasonal and diurnal variations, contributing 2.23 ± 1.27 % (2.30 ± 1.35 % in the daytime and 2.18 ± 1.19 % at night) and 8.60 ± 4.02 % (8.98 ± 3.67 % and 8.21 ± 4.39 %) to OC in winter and summer, respectively. Isoprene and α/β-pinene SOC were obviously elevated in summer, especially in the daytime, mainly due to strong photooxidation. Anthropogenic SOC from toluene and naphthalene oxidation contributed higher to OC in summer (21.0 ± 18.5 %) than in winter (9.58 ± 3.68 %). In summer, toluene SOC was the dominant contributor to aerosol OC, and biomass burning OC also accounted for a large portion to OC, especially in the nighttime, which indicate that land/sea breezes also play an important role in aerosol chemistry at the coastal city of Tianjin in North China.
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