炼锌废渣-修复植物-凋落物体系的生态化学计量学研究

为揭示金属冶炼废渣堆场生态修复多年后,废渣-植物-凋落物系统中养分循环和系统维持机制。该研究以实现生态修复6 a的黔西北铅锌冶炼废渣堆场上土荆芥(Dysphania ambrosioides)、芦竹(Arundo donax)、刺槐(Robinia pseudoacacia)、构树(Broussonetia papyrifera)和柳杉(Cryptomeria fortunei)五种优势修复植物为对象,分析它们的主要营养器官(细根、粗根、茎/干、枝、叶片)、地表凋落物、植被下方表层废渣(0～10 cm)中碳(C)、氮(N)、磷(P)含量及化学计量特征,探讨它们之间的相互关系。结果表明:不同植物、不同营养器官间C、N、P的含量具有显著差异(P<0.05),C平均含量在两种草本植物中为茎>叶片>根>凋落物,在三种乔木中为干>枝>细根>粗根>叶片>凋落物; N和P的分布在草本植物中分别为叶片>凋落物>根>茎和叶片>根>凋落物>茎,在三种乔木中均为叶片>细根>凋落物>粗根>枝>...     

关于复合呼吸机械负荷生理、心理效应的观察与分析

以12名男性成年为被试者,观察了外加死腔(V_(ADS))与吸气阻力(RI)对呼吸型式、通气功能以及呼吸不适感觉的联合影响。结果表明:(1)V_(ADS)及R_I对吸气相面罩腔(口腔)压力(P_I)及外呼吸功率(W_I)具有协同的增强作用;复合呼吸机械负荷的强度越大,此种协同作用也越加明显。(2)无论V_(ADS)及R_I的比例关系如何,反应呼吸不适感觉强度的类别量值(S)与P_I(或W_I)之间,总是符合共同的线性关系,故可以P_I(或W_I)作为复合呼吸机械负荷的综合强度指标。(3)在所观察范围内,V_(ADS)并不影响对阻力性机械负荷的呼吸调节功能。以上结果对制订呼吸防护装备生理标准有一定意义。     

In Situ Assembly of 2D Conductive Vanadium Disulfide with Graphene as a High‐Sulfur‐Loading Host for Lithium–Sulfur Batteries

Lithium–sulfur (Li–S) batteries are deemed to be one of the most promising energy storage technologies because of their high energy density, low cost, and environmental benignancy. However, existing drawbacks including the shuttling of intermediate polysulfides, the insulating nature of sulfur, and the considerable volume change of sulfur cathode would otherwise result in the capacity fading and unstable cycling. To overcome these challenges, herein an in situ assembly route is presented to fabricate VS₂/reduced graphene oxide nanosheets (G–VS₂) as a sulfur host. Benefiting from the 2D conductive and polar VS₂ interlayered within a graphene framework, the obtained G–VS₂ hybrids can effectively suppress the polysulfide shuttling, facilitate the charge transport, and cushion the volume expansion throughout the synergistic effect of structural confinement and chemical anchoring. With these advantageous features, the obtained sulfur cathode (G–VS₂/S) can deliver an outstanding rate capability (≈950 and 800 mAh g^?1 at 1 and 2 C, respectively) and an impressive cycling stability at high rates (retaining ≈532 mAh g^?1 after 300 cycles at 5 C). More significantly, it enables superior cycling performance of high‐sulfur‐loading cathodes (achieving an areal capacity of 5.1 mAh cm^?2 at 0.2 C with a sulfur loading of 5 mg cm^?2) even at high current densities.     

Intestinal Autophagy Improves Healthspan and Longevity in C. elegans during Dietary Restriction

Dietary restriction (DR) is a dietary regimen that extends lifespan in many organisms. One mechanism contributing to the conserved effect of DR on longevity is the cellular recycling process autophagy, which is induced in response to nutrient scarcity and increases sequestration of cytosolic material into double-membrane autophagosomes for degradation in the lysosome. Although autophagy plays a direct role in DR-mediated lifespan extension in the nematode Caenorhabditis elegans, the contribution of autophagy in individual tissues remains unclear. In this study, we show a critical role for autophagy in the intestine, a major metabolic tissue, to ensure lifespan extension of dietary-restricted eat-2 mutants. The intestine of eat-2 mutants has an enlarged lysosomal compartment and flux assays indicate increased turnover of autophagosomes, consistent with an induction of autophagy in this tissue. This increase in intestinal autophagy may underlie the improved intestinal integrity we observe in eat-2 mutants, since whole-body and intestinal-specific inhibition of autophagy in eat-2 mutants greatly impairs the intestinal barrier function. Interestingly, intestinal-specific inhibition of autophagy in eat-2 mutants leads to a decrease in motility with age, alluding to a potential cell non-autonomous role for autophagy in the intestine. Collectively, these results highlight important functions for autophagy in the intestine of dietary-restricted C. elegans.     

Validation and Assessment of Three Methods to Estimate 24-h Urinary Sodium Excretion from Spot Urine Samples in Chinese Adults

24-h urinary sodium excretion is the gold standard for evaluating dietary sodium intake, but it is often not feasible in large epidemiological studies due to high participant burden and cost. Three methods—Kawasaki, INTERSALT, and Tanaka—have been proposed to estimate 24-h urinary sodium excretion from a spot urine sample, but these methods have not been validated in the general Chinese population. This aim of this study was to assess the validity of three methods for estimating 24-h urinary sodium excretion using spot urine samples against measured 24-h urinary sodium excretion in a Chinese sample population. Data are from a substudy of the Prospective Urban Rural Epidemiology (PURE) study that enrolled 120 participants aged 35 to 70 years and collected their morning fasting urine and 24-h urine specimens. Bias calculations (estimated values minus measured values) and Bland-Altman plots were used to assess the validity of the three estimation methods. 116 participants were included in the final analysis. Mean bias for the Kawasaki method was -740 mg/day (95% CI: -1219, 262 mg/day), and was the lowest among the three methods. Mean bias for the Tanaka method was -2305 mg/day (95% CI: -2735, 1875 mg/day). Mean bias for the INTERSALT method was -2797 mg/day (95% CI: -3245, 2349 mg/day), and was the highest of the three methods. Bland-Altman plots indicated that all three methods underestimated 24-h urinary sodium excretion. The Kawasaki, INTERSALT and Tanaka methods for estimation of 24-h urinary sodium excretion using spot urines all underestimated true 24-h urinary sodium excretion in this sample of Chinese adults. Among the three methods, the Kawasaki method was least biased, but was still relatively inaccurate. A more accurate method is needed to estimate the 24-h urinary sodium excretion from spot urine for assessment of dietary sodium intake in China.     

An exploration of spatial auditory BCI paradigms with different sounds: music notes versus beeps

Visual brain-computer interfaces (BCIs) are not suitable for people who cannot reliably maintain their eye gaze. Considering that this group usually maintains audition, an auditory based BCI may be a good choice for them. In this paper, we explore two auditory patterns: (1) a pattern utilizing symmetrical spatial cues with multiple frequency beeps [called the high low medium (HLM) pattern], and (2) a pattern utilizing non-symmetrical spatial cues with six tones derived from the diatonic scale [called the diatonic scale (DS) pattern]. These two patterns are compared to each other in terms of accuracy to determine which auditory pattern is better. The HLM pattern uses three different frequency beeps and has a symmetrical spatial distribution. The DS pattern uses six spoken stimuli, which are six notes solmizated as “do”, “re”, “mi”, “fa”, “sol” and “la”, and derived from the diatonic scale. These six sounds are distributed to six, spatially distributed, speakers. Thus, we compare a BCI paradigm using beeps with another BCI paradigm using tones on the diatonic scale, when the stimuli are spatially distributed. Although no significant differences are found between the ERPs, the HLM pattern performs better than the DS pattern: the online accuracy achieved with the HLM pattern is significantly higher than that achieved with the DS pattern (p = 0.0028).     

基于TaqMan探针多重实时荧光PCR的肠道特殊菌群绝对定量方法的建立

本研究旨在建立对肠道主要共生菌的快速定量方法。根据细菌16S rRNA基因的保守序列并参考相关研究,设计针对总肠道菌群的通用引物和探针,以及针对双歧杆菌属、肠球菌属和肠杆菌科的特异性引物和探针,采用引物设计工具(Primer-BLAST) 以及聚合酶链式反应(polymerase chain reaction, PCR)扩增以验证引物和探针的特异性。通过分子克隆技术,构建各目标菌属目的基因的重组质粒作为qPCR检测的标准模板,选择标准模板进行重复性实验,并计算组内和组间重复变异系数。用所建立的方法对不同年龄段的临床粪便标本进行3类细菌的检测,并初步分析这些菌群与增龄的关系。结果显示,引物和探针具有较高的特异性;各目的细菌标准曲线在一定范围内线性关系良好,总菌群或各目标菌属的线性范围分别为：总菌群2.9×10³～2.9×10¹²copies/μL、双歧杆菌3.1×10²～3.1×10⁹ copies/μL、肠球菌5.9×10²～5.9×10⁹ copies/μL、肠杆菌6.3×10²～6.3×10⁹ copies/μL,决定系数R²≥ 0.995;检测的最低拷贝数为总菌群7.5×10² copies/μL、双歧杆菌 46 copies/μL、肠球菌 37 copies/μL、肠杆菌 51 copies/μL;重复性实验变异系数在1.32%以下,具有良好的可重复性。对不同年龄段临床粪便标本检测的结果显示,肠球菌和肠杆菌含量随增龄呈增长趋势,且老年组含量显著高于青年组,但在高龄老年人中未发现肠球菌数量增加。双歧杆菌含量随增龄减少,且各组间差异显著,在高龄老年人中也未观察到双歧杆菌显著减少。结果提示,本研究建立了一种可供临床推广的菌群绝对定量方法,能够同时检测3类细菌和菌群总量,对于菌群定量研究具有实际意义。