In situ Lu–Hf phosphate geochronology: Progress towards a new tool for space exploration

Geochronology is fundamental to understanding planetary evolution. However, as space exploration continues to expand, traditional dating methods, involving complex laboratory processes, are generally not realistic for unmanned space applications. Campaign-style planetary exploration missions require dating methods that can (1) rapidly resolve age information on small samples, (2) be applied to minerals common in mafic rocks, and (3) be based on technologies that could be installed on future rover systems. We demonstrate the application of rapid in situ microanalytical Lu–Hf phosphate geochronology using samples of pallasite meteorites, which are representative examples of the deep interiors of differentiated planetoids that are generally difficult to date. Individual pallasites were dated by laser ablation tandem mass-spectrometry (LA-ICP-MS/MS), demonstrating a rapid novel method for exploring planetary evolution. Derived formation ages for individual pallasites agree with traditional methods and have <2% uncertainty, opening an avenue of opportunity for remote micro-analytical space exploration.     

基于皱纹盘鲍(Haliotis discus hannai)EST数据库的串联重复序列特征分析

皱纹盘鲍大规模EST的分析研究较少,为了研究其基因组转录本的基本特征并为皱纹盘鲍中开发EST-SSR功能性标记奠定基础,我们利用生物信息学手段对NCBI公共数据库中的5784条皱纹盘鲍EST序列进行EST-SSR特征分析。分析结果表明:(1)皱纹盘鲍EST中串联重复序列类型丰富;(2)皱纹盘鲍EST Gene Ontology注释序列SSR类型单一;(3)皱纹盘鲍EST-SSR分布广泛富,是EST-SSR标记开发的优良资源。     

Comparative mitochondrial genome analysis of Varunidae and its phylogenetic implications

Complete mitochondrial genomes(mitogenomes) can indicate phylogenetic relationships, as well as useful information for gene rearrangement mechanisms and molecular evolution. Currently, the phylogenetic location of the genus Varuna(Brachyura: Varunidae) has not been well resolved mainly because of limited representatives(only two extant species). Here, we determined a new mitogenome of this genus(Varuna litterata) and added the published mitogenomes to reconstruct the phylogeny of Varunidae. The ...     

Determination of Sulfamethoxazole and Trimethoprim and Their Metabolites in Hospital Effluent

In this work, an analytical methodological study was carried out to determine the antimicrobials sulfamethoxazole and trimethoprim, as well as their metabolites, in hospital effluent. The determinations were conducted by liquid chromatography tandem mass spectrometry using a hybrid triple quadrupole‐linear ion trap mass spectrometer (LC‐QqLIT‐MS). The data acquisition was made in selected reaction monitoring (SRM) mode, in which two SRM transitions were monitored to ensure that the target compounds were accurately identified by the information dependent acquisition (IDA) function. The limits of detection (LOD) and quantification (LOQ) were 0.25 and 0.80 µg L^?1 for sulfamethoxazole and 0.15 and 0.50 µg L^?1 for trimethoprim. The linear range for the SMX was 0.8–100.0 µg L^?1 and TMP was 0.5–100.0 µg L^?1 on the basis of six‐point calibration curves generated by means of linear regression analysis. The coefficients of the correlation were higher than 0.999, which ensured the linearity of the method. The average concentration of sulfamethoxazole and trimethoprim found in hospital effluent was 27.8 and 6.65 µg L^?1, respectively. The analytical methodology employed allowed two metabolites to be identified, N4‐acetyl‐sulfamethoxazole and α‐hydroxy‐trimethoprim. Fragmentation pathways were proposed.     

不等直径串列双圆柱体绕流的数值模拟

利用Fluent软件模拟雷诺数为200时不同间距比G/D和直径比d/D情况下的圆柱绕流现象。根据模拟结果分析G/D和d/D对圆柱体的涡脱落形态,大、小柱体的升力,阻力系数和St数的影响,结果表明涡脱落形态随着G/D和d/D的变化呈现不同的形式,在G/D小于临界间距比时呈现单一涡脱落形态,在G/D大于临界间距比时,呈现双旋涡脱落形态;临界间距比随着d/D增大而增大。在临界间距比附近大、小柱体的升力和阻力系数值及St数变化较大,大、小柱体的St数具有相同的变化规律,St随着d/D的增大而减小。     

串联养殖模式下的凡纳滨对虾(Litopenaeus vannamei)与缢蛏(Sinonovacula constricta)生长特性、消化免疫及水生态效应

虾蛏串养模式作为海水围塘养殖坚持可持续发展、绿色发展的模式,已在福建沿海地区推广,取得明显效果,但目前适宜于该模式下的虾蛏数量配比尚不清楚。在实验室内,通过设立LP组(虾蛏数量配比1︰3)、MP组(1︰5)、HP组(1︰7),模拟虾蛏串联养殖模式,对虾和缢蛏分别投喂颗粒饲料、微绿球藻和角毛藻,并对虾蛏生长特性、养殖环境水质因子、消化与免疫指标、环境与蛏内脏团微生物群落进行探究。结果表明,LP组和MP组虾蛏增重率和特定生长率显著高于HP组。LP组和MP组对虾增重率分别为43.88%、41.91%,缢蛏增重率分别为29.30%、29.40%。水质营养盐浓度开始总体升高达到峰值后总体下降。虾蛏对环境反应不同,缢蛏中淀粉酶和过氧化氢酶活性变化显著,对虾则是胰蛋白酶和超氧化物歧化酶活性变化显著。RDA分析表明,总氮、活性磷酸盐是影响微生物群落关键因素。16S rRNA分析表明,虾蛏不同数量配比对养殖环境以及缢蛏内脏团有较大影响,与LP组相比, MP组和HP组微生物种类更多,且参与氮磷循环的微生物丰度增加。当虾蛏数量配比为1︰3或者1︰5时,虾蛏能良好生长且串养系统养殖环境能起到改善作用。研究结果...     

沉积物中14种典型人工合成麝香加速溶剂萃取-气相色谱-串联质谱快速分析方法研究

近年人工合成麝香在环境中污染状况加剧,该类化合物具有潜在致癌和环境激素作用,对人类健康构成了威胁,因此越来越受到科学工作者的重视。水和土壤等环境样品中的人工合成麝香检测技术发展迅速,并朝着快速绿色的方向发展。人工合成麝香在沉积物中的浓度达到了几个到几千个ng/g的水平,但对于沉积物复杂基质中的多种类人工合成麝香,采取同步提取与净化,并快速分析的方法还有待研究。本文建立了沉积物样品中硝基麝香、多环麝香和大环麝香共三类、14种典型人工合成麝香的快速分析方法。通过实验优化了提取溶剂、提取温度、在线净化吸附剂等条件,大大降低了样品的前处理成本。最终确定样品采用加速溶剂萃取,萃取池中依次装入净化吸附剂(0.4g GCB和1.0g SAX)及5.0g沉积物样品,在80℃条件下采用提取溶剂正己烷-丙酮(4∶1,V/V)循环提取2次,提取液浓缩后采用气相色谱-三重四极杆串联质谱(GC-MS/MS)进行测定。结果表明:14种目标化合物的线性范围为5～200ng/mL,平均添加回收率为70.6%～121.5%,相对标准偏差(RSD,n=7)为0.97%～19.5%。替代物回收率为72.2%～116.8%,方法检出限为硝基麝香0.10～0.19ng/g,多环麝香0.09～0.14ng/g,大环麝香0.11～1.93ng/g。该方法能够满足复杂基质沉积物样品的分析要求。     

Hygroscopic growth of aerosol particles and its influence on nucleation scavenging in cloud: Experimental results from Kleiner Feldberg

The hygroscopic growth of individual aerosol particles has been measured with a Tandem Differential Mobility Analyser. The hygroscopic growth spectra were analysed in terms of diameter change with increasing RH from 20% to 85%. The measurements were carried out during the GCE cloud experiment at Kleiner Feldberg, Taunus, Germany in October and November 1990.Two groups of particles with different hygroscopic growth were observed. The less-hygroscopic group had average growth factors of 1.11, 1.04 and 1.02 for particle diameters of 50, 150 and 300 nm, respectively. The more-hygroscopic group had average growth factors of 1.34, 1.34, and 1.37 for the same particle diameters. The average fraction of less-hygroscopic particles was about 50%. Estimates of the soluble fractions of the particles belonging to the two groups are reported.Hygroscopic growth spectra for total aerosol, interstitial aerosol and cloud drop residuals were measured. A comparison of these hygroscopic growths of individual aerosol particles provides clear evidence for the importance of hygroscopic growth in nucleation scavenging. The measured scavenged fraction of particles as a function of diameter can be explained by the hygroscopic growth spectra.     

不同运动自由度组合串列双圆柱涡激振动数值模拟

基于自主研发的紧致插值曲线CIP (Constrained Interpolation Profile)方法数学模型,对均匀来流条件时不同运动自由度组合下的串列双圆柱涡激振动问题开展二维数值模拟。模型针对雷诺数Re=100,质量比m*=2的串列双圆柱涡激振动问题,选取上、下游圆柱不同运动自由度组合工况进行模拟。重点分析圆柱的升阻力系数、运动位移随折合速度Ur变化的响应。研究表明:当上游圆柱双自由度运动时,随着下游圆柱运动自由度的增加,下游圆柱对上游圆柱涡激振动响应的影响减弱;当下游圆柱双自由度运动时,随着上游圆柱运动自由度的增加,上游圆柱对下游圆柱涡激振动响应的影响变强。研究结果表明圆柱运动自由度组合形式对串列双圆柱涡激振动的影响不可忽略。     

基于动态耦合的FPSO串靠外输所需拖力快速预报

以极浅水作业水深的FPSO串靠外输作业为背景,研究穿梭油轮尾部定位拖轮所需拖力大小,提出了基于动态耦合效应的拖轮拖力直接计算方法。基于三维势流理论,考虑浮式生产储油平台(FPSO)与穿梭油轮之间相互水动力干扰,进行动态耦合计算,根据力学平衡原理求得所需的拖轮拖力并分析其影响因素。结果表明:动态耦合模型算出的所需拖力值较之准动态模型更安全、经济;当FPSO与穿梭油轮距离为80 m时,既能保证外输安全性又能保证经济性;增大两船间距、增加穿梭油轮吃水、两船间采用双缆系泊,均能有效降低所需的拖轮拖力。研究结果可为FPSO串靠外输作业操作提供指导,具有一定的工程实用性。