mlsa-iai-msu-lab/ru_sci_bench_zho_cite_reranking huggingface dataset:
Spatial variability of soil total nitrogen, phosphorus and potassium in Renshou County of Sichuan Basin, China

Understanding soil nutrient distributions and the factors affecting them are crucial for fertilizer management and environmental protection in vulnerable ecological regions. Based on 555 soil samples collected in 2012 in Renshou County, located in the purple soil hilly area of Sichuan Basin, China, the spatial variability of soil total nitrogen (TN), total phosphorus (TP) and total potassium (TK) was studied with geostatistical analysis and the relative roles of the affecting factors were quantified using regression analysis. The means of TN, TP and TK contents were 1.12, 0.82 and 9.64 g kg~(-1), respectively. The coefficients of variation ranged from 30.56 to 38.75% and the nugget/sill ratios ranged from 0.45 to 0.61, indicating that the three soil nutrients had moderate variability and spatial dependence. Two distribution patterns were observed. TP and TK were associated with patterns of obvious spatial distribution trends while the spatial distribution of TN was characterized by higher variability. Soil group, land use type and topographic factors explained 26.5, 35.6 and 8.4% of TN variability, respectively, with land use being the dominant factor. Parent material, soil group, land use type and topographic factors explained 17.5, 10.7, 12.0 and 5.0% of TP variability, respectively, and both parent material and land use type played important roles. Only parent material and soil type contributed to TK variability and could explain 25.1 and 13.7% of TK variability, respectively. More attention should focus on adopting reasonable land use types for the purposes of fertilizer management and consider the different roles of the affecting factors at the landscape scale in this purple soil hilly area.
Computational study of fluid-borne noise in vertical inline pump

The objective of present work is to find out the sources of fluid-borne noise in vertical inline pump for various flow rates. The three-dimensional unsteady Reynolds Average Navier Stokes equation was solved using computational fluid dynamics code to predict the acoustic distribution. The pump chosen for study was of low specific speed and the experimental performance characteristic was very well matched with computational head developed. PROUDMAN sound power contour analysis showed the critical zone of noise in inlet pipe,impeller,and volute. Based on this,the variations of acoustic power were depicted over the cross section of inlet pipe,along the mean streamline of inlet pipe,as well along the volute circumference. The result concludes that the predominant flow noise is at tongue region and followed by noise generated due to turbulence in inlet pipe which occurs by the sudden variation in flow passage as well it depends on the operating condition of pump. The frequency analysis gives a glimpse of understanding about the broadband noise distribution due to flow phenomenon over a frequency range.
The central circadian clock proteins CCA1 and LHY regulate iron homeostasis in Arabidopsis

Circadian clock is the endogenous timekeeping machinery that synchronizes an organism’s metabolism,behavior,and physiology to the daily lightdark circles,thereby contributing to organismal fitness.Iron (Fe) is an essential micronutrient for all organisms and it plays important roles in diverse processes of plant growth and development.Here,we show that,in Arabidopsis thaliana,loss of the central clock genes,CIRCADIAN CLOCK ASSOCIATED 1 (CCA1) and LATE ELONGATED HYPOCOTYL (LHY),results in both reduced Fe uptake and photosynthetic efficiency,whereas CCA1 overexpression confers the opposite effects.We show that root Fe(III) reduction activity,and expression of FERRIC REDUCTION OXIDASE 2 (FRO2) and IRON-REGULATED TRANSPORTER 1 (IRT1) exhibit circadian oscillations,which are disrupted in the cca1 lhy double mutant.Furthermore,CCA1 directly binds to the specific regulatory regions of multiple Fe homeostasis genes and activates their expression.Thus,this study established that,in plants,CCA1 and LHY function as master regulators that maintain cyclic Fe homeostasis.
Compact solid-state waveguide lasers operating in the pulsed regime: a review [Invited]

Over the last years, there has been tremendous progress with compact pulsed lasers based on various solid-state gain media, such as crystals and glasses doped with laser-active ions. With the integration of increasingly diverse saturable absorber materials, these small sources are capable of delivering stable pulses with durations as short as femtoseconds and repetition rates exceeding 10 GHz. These promising sources are known as solid-state waveguide lasers, which have become synonymous with miniaturization, integration, and functionality. This article overviews the progress in the development of passively Q-switched and mode-locked solid-state waveguide lasers employing diverse saturable absorbers. The most commonly used laser configurations,state-of-the-art waveguide fabrication techniques, and experimental demonstrations of pulsed waveguide lasers are summarized and reviewed. Selected well-noted topics, which may shape the future directions in this field, are also presented.
A rare case of Staphylococcus lugdunensis septicemia associated with myocarditis and atrioventricular block

Myocarditis is a relatively rare, possibly life-threatening disease characterized by the inflammation of the myocardium. The disease pathogenesis is primarily initiated by acute injury and necrosis of cardiomyocytes, leading to an inflammatory response mediated by the immune system that can potentially cause further aggravation of myocardial damage and organ dysfunction. Prognosis in patients with myocarditis depends on the clinical presentation, which ranges from an asymptomatic disease course to the concomitant development of cardiac arrhythmias, heart failure, cardiogenic shock and even the occurrence of death in extreme cases. Amongst the infective etiologies, although viral infections are the most common, infections of bacterial and protozoal origin have also been implicated. The present study describes a rare case of Staphylococcus lugdunensis (S. lugdunensis) myocarditis complicated by 1st and 2nd degree atrioventricular block (AVB).
Factors associated with intensification of antihypertensive drug therapy in patients with poorly controlled hypertension

Objective To assess antihypertensive management of older patients with poor blood pressure (BP) control. Methods Physicians, voluntary participating in the study, included six consecutive hypertensive patients during routine visits. Hypertension had to have been previously recognized and averaged office BP was ≥ 140 and/or ≥ 90 mmHg in spite of ≥ 6 weeks of antihypertensive therapy. The physicians completed a questionnaire on patients’ history of cardiovascular (CV) risk factors, comorbidities, home BP monitoring, anthropometric data and the pharmacotherapy. Results Mean age of the 6462 patients was 61 years, 7% were ≥ 80 years, 51% were female. Mean ± SD office BP values were 158 ± 13/92 ± 10 mmHg. The most commonly prescribed antihypertensive drugs were: diuretics (67%), ACE inhibitors (64%), calcium channel blockers (58%) and β-blockers (54%), and their use increased with age. On monotherapy or dual therapy, 43% of the patients and 40% had their latest treatment modification within six months. Home BP monitoring was a factor that accelerated the modification of the therapy. Older patients had to have less chance on faster modification of antihypertensive therapy in spite of presence of diabetes and higher systolic BP. Conclusions Our study suggests that a large number of outpatients with poor BP control receive suboptimal antihypertensive therapy, especially in primary care. In older patients, higher BP values in the office settings are more frequently accepted by physicians even in case of higher CV risk. Regular home BP monitoring hastens the decision to intensify of antihypertensive treatment.
替诺福韦抗病毒治疗的相关肾损害

替诺福韦(tenofovir,TDF)作为一种新型核苷酸类反转录酶抑制剂,于2001年10月,美国食品药品监督管理局(FDA)已批准其用于人类免疫缺陷病毒(HIV)感染的治疗,2008年8月又获准用于治疗慢性乙型肝炎(CHB).2013年TDF进入中国并用于治疗HIV感染,2014年获准用于治疗CHB.TDF半衰期较长,约为72 h,可每天给药1次,提高了需长期用药患者的依从性,且抗病毒作用强,耐药率低,目前已成为治疗 HIV及乙型肝炎病毒(HBV)感染的一线药物 .在临床试验阶段TDF表现出较好的安全性,肾损害的发生率不超过1%,但上市以后,随着用药人群的增加,用药时间的延续,肾小管坏死、急性肾衰竭和范可尼综合征( Fanconi综合征,一种近曲小管功能异常性疾病,包括肾小管性蛋白尿、肾性糖尿、肾性氨基酸尿、尿磷酸盐合并尿崩症和代谢性酸中毒)等不良事件经常发生.相关文献报道,在抗HIV治疗中,TDF相关肾损害的发生率为4%~7%,其中中度及严重肾功能损害的发生率分别为5%和1.7% ,并开始引起临床重视.本文主要阐述TDF抗病毒治疗的相关肾损害,以期为临床合理使用 TDF提供参考.
钙黏蛋白编码基因19突变相关性癫痫1例

钙黏蛋白编码基因19(protocadherin 19, PCDH19),是限于女性癫痫伴智力低下(epilepsy and mental retardation limited to females,EFMR)的主要致病基因,2008年Dibbens等首次报道,后有学者研究发现少数SCN1A基因突变阴性的女性Dravet患儿携带PCDH19基因杂合突变。本病国内鲜有报道,本研究通过对1例PCDH19基因突变相关癫痫的探讨,希望提高对该病的认识,为临床诊治过程提供指导。
一种多用途的新兴油料作物--油莎豆

油莎豆是集粮、油、牧、饲于一体的,综合利用价值高、开发潜力大的新兴经济作物。为了促进油莎豆资源的有效利用,综述了油莎豆在我国的栽培情况,发展油莎豆产业的优势,以及油莎豆产业发展存在的问题,并提出了建议。我国油莎豆产业发展存在品种退化、规模化生产环节装备空白、加工技术准备不足以及对油莎豆价值认可度有待提高等问题,建议国家相关部门出台相关政策,加大油莎豆的研发、创新,促进油莎豆产业的发展。
骨外尤文氏肉瘤/外周原始神经外胚层瘤一例

椎管内PNET的MRI表现: T1WI呈等信号,T2WI呈等或混杂信号,增强扫描一般明显强化,病变可分布于硬膜外、硬膜下,可累及神经或脊髓[3]。由于椎管内PNET发病率低,影像学表现不典型,临床极易误诊。椎管内PNET需要与椎管内神经鞘瘤和脊膜瘤进行鉴别,PENT较神经鞘瘤和脊膜瘤更具有恶性肿瘤征象,对邻近椎体和附件的破坏以及软组织肿胀等更加明显。本例患者就可见多个椎体信号异常,虽然椎体没有进行病理学检查,但是ECT考虑骨转移可能性大。PNET确诊依靠病理学检查,主要通过光镜结合免疫组织化学,有条件者还可以进行基因检测。
肉苁蓉微型饮片切制工艺优化

目的优化肉苁蓉饮片的切制工艺.方法采用正交试验的方法,以饮片截面直径、厚度、软化时间、干燥温度为影响因素,休止角、浸出物、毛蕊花糖苷、松果菊苷、异类叶升麻苷、含有量为评价指标,优化饮片切制工艺.结果最佳切制工艺为饮片截面直径3 ~ 4 mm,厚度1 ~ 2 mm,软化时间2 h,干燥温度70 ℃.结论该方法合理可行,适用于肉苁蓉饮片的切制及应用.
八宝五胆药墨长期用药对大鼠肝肾功能、血糖、血脂的影响

目的考察八宝五胆药墨长期用药对大鼠肝肾功能、血糖、血脂的影响.方法120只大鼠随机分为正常对照组及八宝五胆药墨低、中、高剂量组,各组给药24周后再停药2周.于给药12、24周及停药2周后,大鼠腹主动脉取血,检测肝肾功能、血糖、血脂指标水平及脏器组织.结果与正常对照组比较,给药12、24周及停药2周后,大鼠肝肾功能、血糖、血脂指标水平均未见与药物相关的毒性反应,脏器组织也无明显变化.结论八宝五胆药墨长期用药(24周)对大鼠肝肾功能、血糖、血脂无明显影响,毒性较小,安全性良好.
玉屏风颗粒对腹膜透析患者免疫功能的影响

目的探讨玉屏风颗粒对持续性非卧床腹膜透析患者免疫功能的影响.方法将透析龄在3个月以上68例患者随机分为治疗组(n = 34)和对照组(n = 34),2组均给予常规治疗,治疗组加用玉屏风颗粒5 g,3次/d,口服,治疗周期为4周.对2组患者治疗前后血白细胞、血红蛋白、血白蛋白、甘油三酯、胆固醇等指标进行比较;对2组患者血清IgG、IgA、IgM,补体C3、补体C4,外周血T淋巴细胞亚群进行检测,包括CD3~+、CD4~+、CD8~+百分比、 CD4~+/CD8~+比值,评估免疫功能.结果治疗组治疗后免疫球蛋白A、CD3~+、CD4~+、CD4~+/CD8~+增高,差异有统计学意义(P<0.05);对照组各项指标治疗前后外周血淋巴细胞亚群间比较,差异无统计学意义(P>0.05).结论玉屏风颗粒对于改善腹膜透析患者免疫功能具有积极调节作用.
不同储存时间下八角茴香提取挥发油研究

目的对储存时间不同的八角茴香提取挥发油进行比较.方法通过单因素试验,选择药材粒径大小(A)、浸泡时间(B)、提取时间(C)、加水量(D) 4项为考察因素,用L9(34)进行正交试验设计,优化提取工艺.结果新货最佳提取工艺为药材粒径中粉,浸泡时间1 h,提取时间10 h,加水量10倍;陈货最佳提取工艺为药材粒径中粉,浸泡时间1.5 h,提取时间6 h,加水量10倍.结论新货较陈货提取挥发油得率高,外观颜色更加浅,且反式茴香脑含量较高.
基于sEMG信号的不同年龄下男性肌肉疲劳特性研究

表面肌电图(surface electromyography,sEMG)是记录肌肉肌力首选方法,利用表面电极技术从骨骼肌表面导出多个运动时所产生的电变化在时间和空间叠加,与肌肉的纤维组成、解剖结构及功能状态、运动单元数量、放电频率等都有密切关系。根据医学研究,12-19岁人群被称为Adolescents; 20-29岁人群被称为Vicenarian;30-39岁人群被称为Tricenarian。国内范洪彬等研究不同年龄段肌肉特性和活动不同,国外Ahamed等提出关于在不同年龄范围的男性肌肉活性因电极片贴放位置不同而存在差异性。日前,不同年龄段下肌肉疲劳特性研究已经成为国内外研究的热点,并广泛地应用到临床医学和康复工程等领域。
2018年度地球科学部评审工作综述

2018年,是贯彻落实十九大精神的开局之年,也是国家自然科学基金改革的元年。按照委党组的要求,在分管委主任的领导下,在科学界的大力支持下,地球科学部全体人员坚持以习近平新时代中国特色社会主义思想为指导,贯彻习近平总书记系列重要讲话精神,秉持“依靠专家、发扬民主、择优支持、公正合理”的评审原则,认真贯彻落实《国家自然科学基金“十三五”发展规划》提出的战略定位、发展目标和战略导向,顺利完成了本年度的评审工作,并围绕推动学科交叉、构建良好的科研生态环境等方面进行了有益的实践和积极的思考。
大众传媒中科学传播者的整合构建和社会责任审视——以大型科普节目《加油!向未来》为例

对于科学传播的研究,从定义、发展历程到各派学说,一直是科学传播学者无法达成共识的,但科学传播的必要性和重要性却从未因此降低。随着科学技术的发展和公众科学素养的不断提高,更大范围、更具权威的科学传播变得迫切,而大众媒介无疑是进行科学传播的有力方法之一。可以说,“媒体作为科学与公众之间的界面,起着异乎寻常的作用……无论从有效传播的角度看还是从促进互动的角度看,媒体都是中心和枢纽。”[1]科普书籍、影像资料、电视节目、纪录片以及电影等一直都是重要手段,然而,由于科学本身具有的难度和深度,尤其是传播者自身科学素质的高低,对于科学性的把握容易偏差,使得传播效果并不理想,传播手法也一味迎合受众需求而忽视科学传播的规律,以及自上而下单向传播的传播模式等问题,使得科学传播缺乏权威性、趣味型和交互性。要建立准确有效的科学传播体系,需要传播过程中各个要素的协调合作,包括传播者、传播内容、传播方式、受众和反馈机制,他们各有特点又相互联系,要形成良性传播必须通力协作。本文将着力分析传播者这一要素在科学传播中的作用和责任的建立,从传播者角度探讨以大众传播媒介为主的科学传播方法。
小行星撞击地球的“祸”与“福”

人类赖以生存繁衍的地球和社会的持续发展受到了诸多自然因素和人为因素的潜在威胁。自然因素包括小行星撞击地球、大面积火山爆发和强烈地震与海啸等;人为因素中,如全球性核战争,人类不可持续发展的错误行为等。在地球演化的漫长历史中,小行星撞击地球是诱发地球气候环境灾变、生态系统完全崩溃和地球生物物种大灭绝的元凶。小行星撞击地球诱发的巨大劫难,涉及地球上全部生物物种和人类社会的持续发展,也是人类命运共同体如何能够得以有序健康发展的一个重大科学问题。
A-D-A 型小分子电子给体中的端基优化和高效率光伏器件

相较于传统的无机太阳能电池,有机太阳能电池(OSCs)具备成本低、重量轻、可通过溶液加工方式制备柔性器件等诸多优点,已经成为具有重要应用前景的太阳能利用方式之一1,2.自1995年俞刚等发明了具有本体异质结结构(BHJ)的OSC以来3,采用共轭聚合物电子给体和小分子电子受体材料构建BHJ光伏活性层的电池能量转换效率(PCE)已经达到13%以上4.相比于聚合物材料,有机小分子具备批次差别性较小的优点,针对小分子材料的分子结构设计受到广泛关注.目前,具有拉-推-拉(A-D-A)电子作用的共轭结构已被成功应用到高性能小分子给体与受体材料的分子设计中5–8.根据其光电性能,A-D-A型给体和受体的组合在提供宽吸收光谱和适当的分子能级两方面具有优势,但是采用这种材料组合方式获得光伏效率仍然较低.因此,如何通过材料设计和器件优化提升此类电池的效率是一项具有意义的工作.
深共熔溶剂热合成共轭配体修饰锆/钛氧团簇

金属氧簇化合物属于晶态分子材料,可以通过X射线单晶衍射分析获得精确原子结构,以帮助我们理解结构与性能之间的构效关系规律.特别是钛氧团簇,作为二氧化钛材料的重要模型化合物,近年来吸引了广泛的研究注意力.但是,这类高价金属离子极易水解,而金属氧簇簇核的生长又需要大量的氧桥,这就使其合成具有较高难度.目前常用的合成策略包括溶剂热合成、强酸水溶液组装等.另一方面,为了调控这类氧簇化合物的光吸收特性,促进其在太阳能利用和清洁能源方面的应用,引入有机共轭配体将是有效方法,而传统醇类溶剂对共轭配体较低的溶解能力则又限制了这一方案的实施.针对这些问题,中国科学院福建物质结构研究所张磊、张健研究员等将深共熔溶剂热合成引入到钛氧团簇领域7,近期又利用这一合成方法成功制备了由邻菲罗啉、苯酚等共轭配体修饰的Zr_6以及Ti_(11)Zr_4团簇.他们通过巧妙设计,将苯酚与氯化胆碱按摩尔比2 : 1混合得到一种离子液体,其中苯酚既作为溶剂分子,又可作为簇核的共轭修饰配体.而这一新型离子液体对邻菲罗啉等大共轭配体的溶解能力也会大大增强,有利于将其大量修饰到簇核表面.受益于此,他们所制备的Zr_6簇核由6个苯酚和6个邻菲罗啉配体保护,而Ti_(11)Zr_4簇核则由11个苯酚和8个邻菲罗啉配体保护.所以,从某种意义上说,这类团簇可以看作是具有金属-氧无机核与共轭有机壳的一类特殊分子核壳材料.
杂多酸催化选择氧化甘油

近几十年来,生物柴油作为绿色的生物燃料的技术日趋成熟,在整个生物柴油生产过程中,会产生大约10%(w,质量分数)的副产物甘油,因此通过催化选择氧化甘油过程,获得高附加值化学品引起人们极大的关注.研究表明负载型贵金属催化剂对甘油氧化过程呈现出较高活性和选择性1,2,但是反应通常需要在碱性条件下进行,因此反应后会产生大量的有机酸盐,反应混合物需要进一步中和酸化,才能得到有机酸的目标产物.另外,贵金属催化剂表面受到过度氧化后可能失活3,而且负载型贵金属催化剂在实际应用中价格昂贵.因此,设计更高效、低成本的选择氧化催化剂体系成为当前研究领域的一个热点.除了分子氧之外,过氧化氢作为一种强氧化剂,在较温和的反应条件下被广泛应用于各类有机氧化反应中,它的降解产物只有氧气和水4,因此,近年来人们对过氧化氢作为氧化剂对甘油进行选择性氧化的路径也展开了探索.
Near Earth Vortices Driving of Field Aligned Currents Based on Magnetosphere Multiscale and Swarm Observations

A long-standing mystery in the study of Field-Aligned Currents (FACs) has been that: how the currents are generated and why they appear to be much stronger at high altitudes than in the ionosphere. Here we present two events of magnetotail FACs observed by the Magnetospheric Multiscale Spacecraft (MMS) on 1st July and 14th July 2016,to show how the Substorm Current Wedges (SCW) were formed. The results show that particles were transferred heading towards the Earth during the expansion phase of substorms. The azimuthal flow formed clockwise (counter-clockwise) vortex-like motion, and then generated downward (upward) FACs on the tailward/poleward side of the distorted field with opposite vorticity on their Earthward /equatorward side. We also analyzed the Region 1 FACs observed by the Earth Explorer Swarm spacecraft on 1st July 2016 and found that they were associated with FACs observed by MMS, although differing by a factor of 10. This difference suggests that either there was the closure of the currents at altitudes above 500 km or the currents were not strictly parallel to B and closed at longitudes away from where they were generated.
Active Online Learning in the Binary Perceptron Problem

The binary perceptron is the simplest artificial neural network formed by N input units and one output unit, with the neural states and the synaptic weights all restricted to ± 1 values. The task in the teacher-student scenario is to infer the hidden weight vector by training on a set of labeled patterns. Previous efforts on the passive learning mode have shown that learning from independent random patterns is quite inefficient. Here we consider the active online learning mode in which the student designs every new Ising training pattern. We demonstrate that it is mathematically possible to achieve perfect (error-free) inference using only N designed training patterns, but this is computationally unfeasible for large systems. We then investigate two Bayesian statistical designing protocols, which require 2.3N and 1.9N training patterns, respectively, to achieve error-free inference. If the training patterns are instead designed through deductive reasoning, perfect inference is achieved using N+log_2 N samples. The performance gap between Bayesian and deductive designing strategies may be shortened in future work by taking into account the possibility of ergodicity breaking in the version space of the binary perceptron.
Chiral Extrapolation of Lattice Data of Λ_b → Λ_c Form Factors

An extrapolation to the physical limit for the lattice data of Λ_b → Λ_c form factors computed in the nonphysical region is made in this work through a class of fitting functions proposed by us with nonlinear dependence on m 2 π derived in the chiral perturbative theory (ChPT) and the heavy quark effective theory (HQET) framework. Then the results are applied to calculate the differential and integrated Λ_b → Λ_c semileptonic decay rates. Meanwhile, a comparison between our results and those obtained through the extrapolation functions with naive linear dependence on m 2 π is made. It is shown that the difference between the extrapolated central values of these two cases is about 5%. The total uncertainties (depending on the momentum transfer q 2) in the linear case are about 5% ∼ 10% (caused by the uncertainties of lattice data) and those in the nonlinear case are about 10% ∼ 20% (caused by the uncertainties of both lattice data and input parameters in ChPT and HQET). More accurate lattice data and parameters in ChPT and HQET are needed to reduce the uncertainties of the extrapolated results.
2018年11月十大重要安全漏洞分析

2018年10月21日至2018年11月20日,国家计算机网络入侵防范中心发布漏洞总条目967条,漏洞总数为上月的77%,有所减少.其中威胁级别为“高”的有368条,“中”的有498条,“低”的有101条.威胁级别为“高”的漏洞占到总量的38.06%.从漏洞利用方式来看,能够利用从远程进行攻击的漏洞占绝大多数,这使得攻击者利用相应漏洞发动攻击更为容易.
Nitrogen-cycling microbial community functional potential and enzyme activities in cultured biofilms with response to inorganic nitrogen availability

Biofilms mediate crucial biochemical processes in aquatic ecosystems.It was hypothesized that eutrophication may promote the growth of biofilms,resulting in larger numbers of functional genes.However,the metabolic activity and the roles of biofilms in N cycling will be affected by ambient inorganic nitrogen availability,not by the abundance of functional genes.Biofilms were cultured either with replete inorganic nitrogen (N-rep) or without exogenous inorganic nitrogen supply (N-def) in a flow incubator,and the N-cycling gene abundances (nifH,N2 fixation;amoA,ammonia oxidation,archaea and bacteria;nirS and nirK,denitrification) and enzyme activities (nitrogenase and nitrate reductase) were analyzed.The results showed that,comparing the N-def and N-rep biofilms,the former contained lower nifH gene abundance,but higher nitrogenase activity (NA),while the latter contained higher nifH gene abundance,but lower NA.Different patterns of NA diel variations corresponded to the dynamic microbial community composition and different stages of biofilm colonization.Ammonia oxidizing bacteria (AOB),detected only in N-def biofilms,were responsible for nitrification in biofilms.N-rep biofilms contained high nirS and nirK gene abundance and high denitrification enzyme activity,but N-def biofilms contained significantly lower denitrification gene abundance and activity.In general,the strong N2 fixation in N-def biofilms and strong denitrification in N-rep biofilms assured the balance of aquatic ecosystems.The results suggested that evaluation of the functional processes of N cycling should not only focus on genetic potential,but also on the physiological activity of biofilms.
Microwave mediated synthesis and characterization of CeO_2-GO hybrid composite for removal of chromium ions and its antibacterial efficiency

A facile fabrication and processing of cerium oxide-graphene oxide (CeO_2-GO) hybrid nanocomposites without the use of any surfactant or any organic solvents using chemical method and treatment with microwave irradiation technique are reported.In-situ hexagonal nano cerium oxide particles embedded on the layered surface of GO sheets were investigated for the photodegradation of dyes,removal of chromium Cr(VI) ions and against antibacterial studies.The results imply that hybrid nanocomposites shows enhanced 5-folds of photocatalytic activities in UV (ultraviolet) light irradiation and exhibited rapid efficiency in the elimination of chromium ion better than the pure GO and CeO_2,which are inhibited by competent photosensitive electron inoculation and controlling the electron–hole recombination.The synergetic effect of CeO_2-GO composites played a vital role in showing better results against model bacterium than GO and CeO_2 are due to higher physical interaction endorsed to the stress of membranes acute by piercing edges,large surface area,and higher adsorptive conditions of graphene oxide sheets tailored with ceria particles.The amount of charge transferred at the interface increases with the concentration of O atoms,demonstrating the interaction between CeO_2 and GO is much stronger than CeO_2 and GO are due to the decrease of the average equilibrium distance between the interfaces.The CeO_2-GO interface staggered band alignments existing between the CeO_2 surfaces and GO which shows an excellent synergism.The structure and morphology of composites were tested by X-ray diffraction (XRD),Fourier transform infrared (FTIR),Raman,X-ray photoelectron spectroscopy (XPS),and high-resolution transmission electron microscope (HR-TEM).
Characteristics of volatile organic compounds,NO_2,and effects on ozone formation at a site with high ozone level in Chengdu

Chengdu is a megacity in the southwest of China with high ozone (O_3) mixing ratio.Observation of volatile organic compounds (VOCs),NO_2 and O_3 with high temporal resolution was conducted in Chengdu to investigate the chemical processes and causes of high O_3 levels.The hourly mixing ratios of VOCs,NO_2,and O_3 were monitored by an online system from 28 August to 7 October,2016.According to meteorological conditions,Chengdu,with relative warm weather and low wind speed,is favorable to O_3 formation.Part of the O_3 in Chengdu may be transported from the downtown area.In O_3 episodes,the average mixing ratios of NO_2 and O_3 were 20.20 ppbv and 47.95 ppbv,respectively.In non-O_3 episodes,the average mixing ratios of NO_2 and O_3 were 16.38 ppbv and 35.15 ppbv,respectively.The average mixing ratio of total VOCs (TVOCs) was 40.29 ppbv in non-O_3 episodes,which was lower than that in O_3 episodes (53.19 ppbv).Alkenes comprised 51.7% of the total O_3 formation potential (OFP) in Chengdu,followed by aromatics which accounted for 24.2%.Ethylene,trans-pentene,propene,and BTEX (benzene,ethylbenzene,toluene,m/p-xylene,o-xylene) were also major contributors to the OFP in Chengdu.In O_3 episodes,intensive secondary formations were observed during the campaign.Oxygenated VOCs (OVOCs),such as acetone,Methylethylketone (MEK),and Methylvinylketone (MVK) were abundant.Isoprene rapidly converted to MVK and Methacrolein (MACR) during O_3 episodes.Acetone was mainly the oxidant of C3-C5 hydrocarbons.
Antimony speciation in the environment:Recent advances in understanding the biogeochemical processes and ecological effects

Antimony (Sb) is a toxic metalloid,and its pollution has become a global environmental problem as a result of its extensive use and corresponding Sb-mining activities.The toxicity and mobility of Sb strongly depend on its chemical speciation.In this review,we summarize the current knowledge on the biogeochemical processes (including emission,distribution,speciation,redox,metabolismand toxicity) that trigger themobilization and transformation of Sb from pollution sources to the surrounding environment.Natural phenomena such as weathering,biological activity and volcanic activity,together with anthropogenic inputs,are responsible for the emission of Sb into the environment.Sb emitted in the environment can adsorb and undergo redox reactions on organic or inorganic environmental media,thus changing its existing formand exerting toxic effects on the ecosystem.This review is based on a careful and systematic collection of the latest papers during 2010–2017 and our research results,and it illustrates the fate and ecological effects of Sb in the environment.