限制能量平衡膳食联合运动干预对肥胖儿童身体成分、脂质代谢及肠道菌群的影响

摘要 目的：观察限制能量平衡膳食联合运动干预对肥胖儿童身体成分、脂质代谢及肠道菌群的影响。方法：选取2020年4月至2022年10月期间浙江大学医学院附属儿童医院收治的肥胖儿童104例作为研究对象。按照随机数字表法将肥胖儿童分为对照组（n=52,限制能量平衡膳食）和观察组（n=52,限制能量平衡膳食联合运动干预）。对比两组身体成分、脂质代谢及肠道菌群变化情况。结果：观察组干预2个月后体重、体质量指数（BMI）、去脂体重、脂肪量、体脂率低于对照组（P<0.05）。观察组干预2个月后总胆固醇（TC）、甘油三酯（TG）、低密度脂蛋白胆固醇（LDL-C）低于对照组;高密度脂蛋白胆固醇（HDL-C）高于对照组（P<0.05）。观察组干预2个月后肠球菌、大肠杆菌低于对照组;乳杆菌、双歧杆菌高于对照组（P<0.05）。结论：限制能量平衡膳食联合运动干预可有效改善肥胖儿童身体成分,调节脂质代谢及肠道菌群平衡。     

Intracellular delivery of glutathione S-transferase into mammalian cells

Protein transduction domains (PTDs) derived from human immunodeficiency virus Tat protein and herpes simplex virus VP22 protein are useful for the delivery of non-membrane-permeating polar or large molecules into living cells. In the course of our study aiming at evaluating PTD, we unexpectedly found that the fluorescent-dye-labeled glutathione S-transferase (GST) from Schistosoma japonicum without known PTDs was delivered into COS7 cells. The intracellular transduction of GST was also observed in HeLa, NIH3T3, and PC12 cells, as well as in hippocampal primary neurons, indicating that a wide range of cell types is permissive for GST transduction. Furthermore, we showed that the immunosuppressive peptide VIVIT fused with GST successfully inhibits NFAT activation. These results suggest that GST is a novel PTD which may be useful in the intracellular delivery of biologically active molecules, such as small-molecule drugs, bioactive peptides, or proteins.     

A practical approach to FRET-based PNA fluorescence in situ hybridization

Given the demand for improved methods for detecting and characterizing RNA variants in situ, we developed a quantitative method for detecting RNA alternative splicing variants that combines in situ hybridization of fluorescently labeled peptide nucleic acid (PNA) probes with confocal microscopy Förster resonance energy transfer (FRET). The use of PNA probes complementary to sequences flanking a given splice junction allows to specifically quantify, within the cell, the RNA isoform generating such splice junction as FRET efficiency measure. The FRET-based PNA fluorescence in situ hybridization (FP-FISH) method offers a conceptually new approach for characterizing at the subcellular level not only splice variant isoform structure, location, and dynamics but also potentially a wide variety of close range RNA–RNA interactions. In this paper, we explain the FP-FISH technique workflow for reliable and reproducible results.     

Regional water resource implications of bioethanol production in the Southeastern United States

The Energy Independence and Security Act (EISA) of 2007 mandates US production of 136 billion L of biofuel by 2022. This target implies an appropriation of regional primary production for dedicated feedstocks at scales that may dramatically affect water supply, exacerbate existing water quality challenges, and force undesirable environmental resource trade offs. Using a comparative life cycle approach, we assess energy balances and water resource implications for four dedicated ethanol feedstocks – corn, sugarcane, sweet sorghum, and southern pine – in two southeastern states, Florida and Georgia, which are a presumed epicenter for future biofuel production. Net energy benefit ratios for ethanol and coproducts range were 1.26 for corn, 1.94 for sweet sorghum, 2.51 for sugarcane, and 2.97 for southern pine. Corn also has high nitrogen (N) and water demand (11.2 kg GJ_net^?1 and 188 m³ GJ_net^?1, respectively) compared with other feedstocks, making it a poor choice for regional ethanol production. Southern pine, in contrast, has relatively low N demand (0.4 kg GJ_net^?1) and negligible irrigation needs. However, it has comparatively low gross productivity, which results in large land area per unit ethanol production (208 m² GJ_net^?1), and, by association, substantial indirect and incremental water use (51 m³ GJ_net^?1). Ultimately, all four feedstocks require substantial land (10.1, 3.1, 2.5, and 6.1 million ha for corn, sugarcane, sweet sorghum, and pine, respectively), annual N fertilization (3230, 574, 396, 109 million kg N) and annual total water (54 400, 20 840, 8840, and 14 970 million m³) resources when scaled up to meet EISA renewable fuel standards production goals. This production would, in turn, offset only 17.5% of regional gasoline consumption on a gross basis, and substantially less when evaluated on a net basis. Utilization of existing waste biomass sources may ameliorate these effects, but does not obviate the need for dedicated primary feedstock production. Careful scrutiny of environmental trade‐offs is necessary before embracing aggressive ethanol production mandates.     

Comparison of Zinc Reduction with Platinum Reduction for Analysis of Deuterium‐Enriched Water Samples for the Doubly Labeled Water Technique

Objective: Isotope ratio mass spectrometry of hydrogen and oxygen is frequently used to determine total energy expenditure (TEE) using doubly labeled water. Conventionally, hydrogen isotope ratio is determined in hydrogen gas generated from water samples using zinc reduction. We compare this with a new automated platinum method to determine the ratios of hydrogen isotopes in deuterium‐enriched water samples. Research Methods and Procedures: The platinum method of sample preparation was compared with the zinc method in three ways: analytical variation in deuterium enrichment (within sample; n = 51), analytical variation in TEE estimates (within sample set; n = 10), and level of agreement of TEE estimates between both methods (n = 14). Results: For the zinc method, the standard deviation for multiple sets of triplicate ²H₂O sample analysis was ±4.36‰ and ±2.07‰ for platinum. The correlation between TEE estimates when sample sets were analyzed in duplicate was r = 0.89 for zinc and r = 0.83 for platinum. The intercept and slope of the regression line were significantly different from the line of identity for duplicate TEE estimates by zinc but were not different from the line of identity for platinum. After correction for the intra‐assay variation of each method, the correlation between zinc and platinum for TEE was 0.77, and the intercept, but not the slope, of the regression was significantly different from the line of identity. The mean difference between the zinc method and the platinum method was 56 kcal/day, and the 95% confidence interval was ?438 to 550 kcal/day. Discussion: These data suggest that the platinum method is at least as reliable as the zinc method as a sample preparation technique for isotope ratio mass spectrometry of deuterium‐enriched water samples. The platinum method is also less costly and less labor‐intensive than the zinc method.     

Single Nanostructure Electrochemical Devices for Studying Electronic Properties and Structural Changes in Lithiated Si Nanowires

Nanostructured Si is a promising anode material for the next generation of Li‐ion batteries, but few studies have focused on the electrical properties of the Li‐Si alloy phase, which are important for determining power capabilities and ensuring sufficient electrical conduction in the electrode structure. Here, we demonstrate an electrochemical device framework suitable for testing the electrical properties of single Si nanowires (NWs) at different lithiation states and correlating these properties with structural changes via transmission electron microscopy (TEM). We find that single Si NWs usually exhibit Ohmic I–V response in the lithiated state, with conductivities two to three orders of magnitude higher than in the delithiated state. After a number of sequential lithiation/delithiation cycles, the single NWs show similar conductivity after each lithiation step but show large variations in conductivity in the delithiated state. Finally, devices with groups of NWs in physical contact were fabricated, and structural changes in the NWs were observed after lithiation to investigate how the electrical resistance of NW junctions and the NWs themselves affect the lithiation behavior. The results suggest that electrical resistance of NW junctions can limit lithiation. Overall, this study shows the importance of investigating the electronic properties of individual components of a battery electrode (single nanostructures in this case) along with studying the nature of interactions within a collection of these component structures.     

不同表面处理对全瓷材料表面粗糙度及表面自由能的影响

目的:比较分析三种不同表面处理方法对全瓷材料表面粗糙度及表面自由能的影响。方法:选用两种氧化锆(LAVA Plus,Wieland)和两种玻璃陶瓷(E.max Press,ELDC),按照生产商的制作方法制作成盘状试件(直径13 mm,厚1 mm),并将以上四组全瓷材料按照不同的表面处理方式分别分为以下三个亚组:粗磨组(rough grinding)、抛光组(polishing)和上釉组(glazing)。利用三维形貌扫描仪测量样本表面的面粗糙度(Sa),表面张力仪测量各组样本表面接触角并计算表面自由能。结果:各组材料粗磨组粗糙度值均显著高于其抛光组及上釉组;对于两种氧化锆陶瓷,抛光组与上釉组间粗糙度值无显著差异(P0.05),而对于两种玻璃陶瓷,抛光组的粗糙度值显著低于上釉组(P0.05);上釉组表面自由能均显著高于相应粗磨组及抛光组(P0.05),粗磨组和抛光组间无显著性差异。结论:抛光和上釉均能显著降低全瓷材料的表面粗糙度,对于氧化锆陶瓷,抛光能达到类似上釉的表面粗糙度,对于玻璃陶瓷,抛光能够获得更加光滑的表面。上釉后全瓷材料的表面自由能显著高于抛光组。     

Two‐Dimensional Materials for Beyond‐Lithium‐Ion Batteries

Lithium‐ion batteries (LIBs) have dominated the portable electronics industry and solid‐state electrochemical research and development for the past two decades. In light of possible concerns over the cost and future availability of lithium, sodium‐ion batteries (SIBs) and other new technologies have emerged as candidates for large‐scale stationary energy storage. Research in these technologies has increased dramatically with a focus on the development of new materials for both the positive and negative electrodes that can enhance the cycling stability, rate capability, and energy density. Two‐dimensional (2D) materials are showing promise for many energy‐related applications and particularly for energy storage, because of the efficient ion transport between the layers and the large surface areas available for improved ion adsorption and faster surface redox reactions. Recent research highlights on the use of 2D materials in these future ‘beyond‐lithium‐ion’ battery systems are reviewed, and strategies to address challenges are discussed as well as their prospects.     

Effect of adaptation to high light intensity on the kinetics of energy transfer from phycobilisomes to photosystem II in Anabaena cylindrica

Transfer efficiencies between phycobilisomes and photosystem II antenna chlorophylls were determined on membrane fragments isolated from low and high light adapted Anabaena cells. The observed increase in energy transfer in high light adapted cells is a consequence of shorter interchromophore distances and a decrease in the number of jumps of the exciting photons. Calculation of the rates of energy transfer and the coupling energies indicate that the weak interaction inferred for energy transfer between phycobilisome and photosystem II in low light adapted cells is replaced by an intermediate interaction in high light adapted cells.Abbreviations LLA low light adapted - HLA high light adapted - PBS phycobilisome - PS photosystem