Silver nanoparticles reduce the apoptosis induced by tumor necrosis factor-α

Silver nanoparticles (AgNPs) are widely known to have anti-inflammatory properties, but the exact mechanism underlying this anti-inflammatory effect is not clearly understood. Tumor necrosis factor-α (TNFα) is a major pro-inflammatory cytokine that is expressed in the early stage of cell inflammation and induces apoptosis by several known pathways. Our study aimed to investigate the effect of AgNPs on the response of lung epithelial cells to TNFα and the molecular mechanism of this response. Lung epithelial cell line NCI-H292 cells were exposed to AgNPs (5 µg/mL) and/or TNFα (20 ng/mL) for 24 h, then cellular uptake was analyzed using flow cytometry. Our results showed that AgNPs were taken up by cells in a dose-dependent manner and that the cellular uptake ratio of AgNPs was significantly increased in the presence of TNFα. Apoptosis assays indicated that exposure to AgNPs significantly decreased the apoptotic effect of TNFα. Confocal microscopy was used to localize the tumor necrosis factor receptor 1 (TNFR1) and revealed that TNFR1 localized on the surface of cells exposed to TNFα. In contrast, TNFR1 localized inside cells exposed to both AgNPs and TNFα, with very few receptors scattered on the cell membrane. The results indicated that AgNPs reduced the cell surface TNFR1 expression level. The results suggested that the reduction of surface TNFR1 reduced cellular response to TNFα, resulting in an anti-apoptotic effect.     

不同预冷温度对甜樱桃果实保鲜效果的影响

目的 探究不同预冷温度对采后甜樱桃果实生理品质的影响,找出最适宜的预冷温度,进而推动甜樱桃产业化发展。方法 本实验分别将采后甜樱桃分别预冷至15、12、9、6、3、0℃后回温至室温,以不进行预冷处理为对照组,比较6种处理方式果实预冷和回温过程中的温度变化,并分别测定回温前后果实的色差、呼吸强度及乙烯释放量、硬度、可溶性固形物(TSS)、风味、感官评价,总酚、类黄酮、花色苷、维生素C(Vc)、可溶性蛋白、丙二醛(MDA)含量以及超氧阴离子产生速率(O₂^-)。结果不同预冷温度均可较好地保持果实外观及风味,能够降低甜樱桃果实呼吸强度与乙烯释放量,抑制果实TSS、MDA含量和O₂^-产生速率的上升,延缓甜樱桃果实硬度的下降,从而保持甜樱桃果实的外观品质,且有利于维持甜樱桃果实中的Vc、可溶性蛋白和花色苷含量,以0℃预冷效果最佳,感官评分最高。结论 预冷能够有效维持甜樱桃果实采后的品质,达到增加甜樱桃果实经济价值的作用。     

Multi‐response optimization and empirical modeling of cardiopulmonary responses during manual lifting tasks

An experimental study involving five independent lifting variables (namely weight, lift frequency, horizontal distance from the object, operator, and vertical distance) and their interactions was conducted using the Taguchi L₂₇ design. Two responses—heart rate and oxygen uptake—were measured during each trial. To optimize both responses simultaneously, the signal‐to‐noise ratio was normalized to obtain a multi‐response signal‐to‐noise (MRSN) ratio for each trial. The MRSN ratio was analyzed using analysis of variance to identify the optimal condition in which both responses were optimized at the same time. Lift frequency was found to be the most significant factor, and operator and horizontal distance were found to be least significant. The empirical modeling equation was developed and can be used to predict the response values during experimental trials involving similar work conditions. © 2010 Wiley Periodicals, Inc.     

Google Earth在森林植被营养元素循环研究中的应用

森林植被营养元素循环是森林生态系统分析中的重要参数.将Google Earth应用在其研究过程中具有重要作用.阐述了Google Earth的主要原理和关键技术,重点分析了KML和Google EarthAPI;设计了Google Earth应用的数据处理流程和系统架构;最后实现了基于Google Earth的贵州龙里森林植被营养元素循环研究系统.     

长期施用含氮化肥对大豆生育及养分吸收的影响

从1984年起,在沈阳农业大学棕壤上没有氮化肥长期定位试验。结果表明,长期施用含氯化肥在大豆整个生育期内可促进株高、茎粗、根系等地上部及地下部的生长,氯对大豆氮、磷养分的吸收无明显影响,对钾的吸收有 促进作用。     

Calculating soil nutrient balances in Africa at different scales

Nutrient balances were calculated for the arable soils of 38 sub-Saharan African countries. FAO production figures and forecasts for 35 crops for the period 1982–1984 and for 2000 were used to define land use systems, further characterized by fertility input through fertilizers, manure, rain and dust, biological N-fixation, and sedimentation, and fertility output through harvest of crops and removal of residues, leaching, denitrification, and erosion. The summarized output of the study is the sum of inputs minus the sum of outputs of nitrogen, phosphorus and potassium in the root zone. The alarming annual average nutrient loss for sub-Saharan Africa was 22 kg N, 2.5 kg P, and 15 kg K in 1982–84, and will be 26 kg N, 3 kg P, and 19 kg K in 2000. As the soil nutrient pool has to offset the negative balances each year, there is gross nutrient mining in sub-Saharan Africa. The need for integrated systems of nutrient management is emphasized, manipulating all inputs and outputs in a judicious way. Future scenarios of continued mining and conservation of soil fertility are discussed.     

厌氧/缺氧/好氧膜生物反应器处理城市污水效能研究

采用厌氧/缺氧/好氧膜生物反应器对北京某城市污水处理厂的初沉池出水进行中试试验,约200 d的研究表明,在水力停留时间保持12.5 h后,化学需氧量、生物需氧量及总有机碳的去除率分别稳定在92%、98%、85%左右,其中生化降解部分与膜过滤部分对COD去除的贡献率分别为89%和11%;NH4+-N、总氮(total nitrogen,TN)的去除率分别为98%、79%左右,出水ρ(TN)平均在10 mg/L左右;系统在污泥龄为40 d左右时,总磷(totalphosphorus,TP)平均去除率为85%,出水ρ(TP)在0.93 mg/L左右;反硝化除磷、好氧吸磷、膜截留对总磷的去除所占的比例分别为44.6%、51.8%、3.6%;出水浊度极低且几乎无悬浮物,可直接回用于城市杂用水.间歇抽吸、曝气冲刷、在线水力反冲及定期药洗保证了该系统的可持续运行.     

Physiological and cognitive responses when riding an electrically assisted bicycle versus a classical bicycle

The present study compared the physiological responses and the subsequent cognitive performance when riding an electrically assisted (EB) versus a classical (CB) bicycle. Oxygen uptake, heart rate and leg extensor muscles electromyographic (EMG) activity were recorded in 10 subjects during a 30-min intermittent cycling exercise performed with EB versus CB. Cognitive performance was evaluated by a mail sorting test, performed at rest and after each cycling session. Averaged oxygen uptake and heat rate were significantly (P < 0.05) lower during EB cycling than during CB cycling. The EMG activities of the vastus lateralis, rectus femoris and gastrocnemius medialis muscles were significantly (P < 0.001) greater during CB cycling than during EB cycling. The time to complete the mail sorting test was significantly (P < 0.05) shorter after EB cycling than after CB cycling. Because EB cycling reduced muscle strains and physiological stress, it might offer benefits for those using bicycles in their work, such as postal workers and police officers. STATEMENT OF RELEVANCE: This study compared physiological and cognitive responses when riding an electrically assisted versus a classical bicycle. The results showed that the electrically assisted bicycle led to reduced muscle strains and physiological stress and, therefore, might offer benefits for those using bicycles in their work, such as postal workers and police officers.     

Metabolic and cardiovascular responses to exercise with caffeine

The effect of caffeine on circulation and metabolism was studied during a discontinuous maximal oxygen uptake (VO₂ max) test on a bicycle ergometer. Eight male subjects were chosen for their minimal use of caffeine of which six normally did not ingest caffeinated beverages. Two caffeinated and two decaffeinated (control) trials were administered to each subject following double-blind and counterbalanced testing procedures. One hour before exercise, subjects ingested decaffeinated coffee with or without 350 mg of caffeine anhydrous added. Cardiac output (Q) was measured by a C0₂ rebreathing technique. Compared to control trials, caffeine increased the VO₂ max by an average of 140ml min?¹ (p <0-0·5)l. In addition, during caffeine trials, the average maximal heart rate (HR max) was elevated by 5 beats min^?1 (p<0·01). There were no other statistically significant changes in metabolic (VO₂ and R) and cardiovascular (Q, HR, SV and (a-v) 0₂ diff) variables during either submaximal or maximal exercise. Performance, as measured by total exercise time on the VO₂ max test, was not significantly different (p>0·05). It was concluded that caffeine has a small physiological but a statistically significant effect on VQ₂ max and HR max. During submaximal exercise, caffeine did not significantly effect the cardiovascular system.     

围绕碳源问题进行的脱氮除磷工艺改进

反硝化菌和聚磷菌在同一系统中竞争少量可溶性有机物引起的矛盾一直是传统生物脱氮除磷工艺的焦点问题．在污水处理系统中碳源的缺乏会影响整个系统的脱氮除磷效果．分析了碳源缺乏的原因，提出了着重从两个方面解决碳源缺乏问题：一方面是在时间或空间上将脱氮除磷分开的工艺改进，另一方面是寻找快速可替代有机碳源，并对有代表性的Biowin工艺的运行情况作了分析．