Sequence analysis of peptides with biological activities using electrospray-Fourier trans form ion cyclotron resonance mass spectrometry

The mass spectra of five peptides with biological activities are reported. All mass spectra were recorded using a 4.7-T Fourier transform ion cyclotron resonance mass spectrometer equipped with an external electrospray source. The accurate molecular weights for the five peptides prepared by solid phase synthesis were measured as 1765.9013, 1063.5420, 1092.5254, 820.3804 and 1078.5193, respectively. All the data were obtained with the external calibration. Differences between observed and theoretical monoisotopic molecular weights were in the (0.2—1.0)×10^-6 range. The complete primary sequence for the five polypeptides were determined using the method of in-source electrospray ionization/collision induced dissociation (ESI/CID). All the intact y series ions and b series ions were obtained from various peptides respectively, thus determining the sequences of the five polypeptides. We found that the measured accurate molecular mass of sample 4 was not in agreement with that expected from the planned synthetic peptide. The sequences of sample 4 were determined through analysis. The corresponding accurate masses of b series ions and y series ions were gained, which proved that it was correct to re-determine the sequences.     

原子核质量的测量

质量是原子核最基本的性质之一,核质量数据在核物理、核天体物理及核技术应用等多个领域得到广泛应用.原子核质量的测量是核物理一个重要的前沿研究课题.本文简要回顾了核质量测量的发展历史,综述目前国际上的研究现状,并介绍了原子核质量数据表的评估工作.基于兰州重离子加速器大科学装置,我们建立了等时性质谱术,精确测量了一批短寿命原子核的质量.随后介绍了兰州的质量测量工作,讨论了新质量数据对原子核的同位旋对称性和天体X射线暴研究的影响.     

广西珍珠湾日本鳗草叶片附着卵块的分布特征

海草床由大面积的连片海草植物构成,是许多海洋水生动物的育幼所或产卵所。研究海草植物附着卵块的分布规律,对于揭示海草床的产卵场功能有重要意义。本研究以广西珍珠湾潮间带海草日本鳗草（Zostera japonica）为研究对象,分别于2019年12月（冬季）、2020年5月（春季）和2020年7月（夏季）对叶片开展粘性卵块种类和密度的调查,探讨其季节变化规律及其与海草群落结构的关系。结果显示,调查期间日本鳗草叶片仅有秀丽织纹螺（Nassarius festivus）和奥莱彩螺（Clithon oualaniensis）两种附着卵块,前者在冬季、春季和夏季的卵块密度分别为1 026,191,191 ind./m²,而后者对应的卵块密度分别为0,209,268 ind./m²。同时,日本鳗草叶片下部的附着卵块密度显著高于上部的附着卵块密度。主成分回归分析显示,单株叶面积、地上生物量（干重）以及平均叶长等海草群落结构指标与秀丽织纹螺卵块密度呈显著相关关系,但其与奥莱彩螺卵块密度无显著相关关系。本研究结果表明,日本鳗草叶片附着卵块密度在季节和附着部位上有显著性差异,而且海草床群落结构影响了叶片附着卵的分布。     

中能重离子反应中中子-质子有效质量劈裂的研究

利用同位旋相关的量子分子动力学模型,研究了~(112)Sn+~(112)Sn,~(124)Sn+~(124)Sn和~(132)Sn+~(132)Sn在能量为50,100,200MeV/u的反应系统中,不同中子-质子有效质量劈裂对原子核阻止和中子、质子发射数的影响.结果表明:中子-质子有效质量劈裂对原子核阻止和中子、质子发射数有很明显影响,且原子核阻止和中子、质子发射数随着有效质量劈裂的增加而递减.可以通过实验测定的原子核阻止和中子、质子发射数来确定中子-质子有效质量劈裂的值.     

乙醇超临界技术制备疏水性白炭黑粉体

以硅酸钠为硅源,浓硫酸为酸化剂,在超重力旋转床中制备出二氧化硅,经处理后置于高压釜内,在分别改变溶液体积与高压釜容积比值、滤饼质量或氮气预加压条件下进行乙醇超临界干燥,制得白炭黑粉体。用接触角测定仪、透射电镜、FT-IR红外光谱、氮气吸附容量法、DBP吸油值来表征所得样品。结果表明：所得样品具有极强的疏水性,接触角大都在130°以上,当溶液体积与高压釜容积比值增大时,接触角大体呈增大趋势;当滤饼质量增加时,接触角亦增大;当氮气预加压力增大时,接触角变化规律不明显;所得样品除粒径变化不大外,分散性、比表面积、吸油值等均有规律变化。     

The Siberian Traps and the End-Permian mass extinction: a critical review

The association between the Siberian Traps, the largest continental flood basalt province, and the largest-known mass extinction event at the end of the Permian period, has been strengthened by recently-published high-precision ⁴⁰Ar/³⁹Ar dates from widespread localities across the Siberian province^[1]. We argue that the impact of the volcanism was amplified by the prevailing late Permian environmental conditions―in particular, the hothouse climate, with sluggish oceanic circulation, that was leading to widespread oceanic anoxia. Volcanism released large masses of sulphate aerosols and carbon dioxide, the former triggering short-duration volcanic winters, the latter leading to long-term warming. Whilst the mass of CO₂ released from individual eruptions was small compared with the total mass of carbon in the atmosphere-ocean system, the long ‘mean lifetime’ of atmospheric CO₂, compared with the eruption flux and duration, meant that significant accumulation could occur over periods of 105 years. Compromise of the carbon sequestration systems (by curtailment of photosynthesis, destruction of biomass, and warming and acidification of the oceans) probably led to rapid atmospheric CO₂ build-up, warming, and shallow-water anoxia, leading ultimately to mass extinction.     

High-precision thermal ionization mass spectrometry dating of young volcanic rocks by using U-series method

A high precision thermal ionization mass spectrometric (HP-TIMS) technique is used to determine²³⁸U,²³⁴U,²³²Th,²³⁰Th concentrations and their ratios in whole rocks and minerals separated from Quaternary Maanshan, Dayingshan and Heikongshan volcanic rocks of Tengchong volcanic field, Yunnan Province, China. The²³⁸U-²³⁰Th isochrons are given, yielding four age values (227±20) ka (D-1, Dayingshan), (79.6±5.5) ka (D-7, Dayingshan), (21.9±3.0) ka (h-1, Heikongshan), and (7.5±1.0) ka (M-1, Maanshan). The result is not only consistent with but also preciser than those measured by the K-Ar method and the alpha spectrometry U-series method, indicating that the HP-TIMS method is reliable and has high precision. Besides, a procedure of HP-TIMS analysis of young volcanic rocks in China is set up preliminarily.     

<Emphasis Type="Italic">In situ</Emphasis> measurement of PM<Subscript>1</Subscript> organic aerosol in Beijing winter using a high-resolution aerosol mass spectrometer

Organic aerosol (OA) is a crucial component of atmospheric fine particles. To achieve a better understanding of the chemical characteristics and sources of OA in Beijing, the size-resolved chemical composition of submicron aerosols were measured in-situ using a High-Resolution Time-of-Flight Aerosol Mass Spectrometer in the winter of 2010, with a high time resolution of 5 min. During this study, the mean OA mass concentration was 20.9±25.3 μg/m3, varying between 1.9 and 284.6 μg/m3. Elemental analysis showed that the average H/C, O/C and N/C (molar ratio) were 1.70, 0.17, and 0.005, respectively, corresponding to an OM/OC ratio (mass ratio of organic matter to organic carbon) of 1.37. The average mass-based size distributions of OA present a promi- nent accumulation mode peaking at approximately 450 nm. The prominent presence of ultrafine particles (Dva < 100 nm) was mainly from the fresh emissions of combustion sources. A Positive Matrix Factorisation (PMF) analysis of the organic mass spectral dataset differentiated the OA into three components, including hydrocarbon-like (HOA), cooking-related (COA), and oxygenated (OOA) organic aerosols, which, on average, accounted for 26.9%, 49.7% and 23.4%, respectively, of the total organic mass. The HOA and COA likely corresponded to primary organic aerosol (POA) associated with combustion-related and cooking emissions, respectively, and the OOA components corresponded to aged secondary organic aerosol (SOA).     

Applications of14C-AMS in biomedical sciences (Bio-14C-AMS)

Accelerator mass spectrometry (AMS) is an ultrasensitive measure for tracing¹⁴C labeled moleculesin vivo or detecting the biomarker for assessment of carcinogenesis. In this review, basic principles, wide applications and new progresses of¹⁴C-bio-AMS are presented. It has been a new advanced tool for measuring the adduction of biologcial molecules with xenobiotics, including carcinogens, drugs, agrochemicals, nicotine, etc. The successful applications have proven the effectiveness of AMS to assessing cancer risk, screening drug toxicity and studying nutrients uptake. In particular, AMS is characterized by measuring xenobiotics at very low dose levels relevant to human environmental exposure. It is sensitive and precise to an attomole (10⁻¹⁸ mole) or less of¹⁴C per mg carbon. Although it has some shortcomings, undoubtedly, AMS possesses an evident merit of high sensitivity and will have widespread applications in the biomedical sciences.     

简论依靠群众反腐败

我国反腐败斗争已进入关键阶段 ,要想更有效地打击腐败 ,就必须紧紧依靠群众。因为群众观点 ,是防止腐败产生的根本 ;民心稳定 ,是反腐败斗争的基本前提 ;群众参与 ,是以法治腐的有力保证 ;群众监督 ,是反腐败胜利的重要法宝。     

Synthesis and conductivity of substituted heteropoly acid with Dawson structure H7[Ga（H2O）P2W17061] · 18H2O

A new solid high-proton conductor, H₇[Ga(H₂O)P₂W₁₇O₆₁]??18H₂O, a substituted heteropoly acid with Dawson structure, has been synthesized by the degradation/ion-exchange/freezing method. The product was characterized by potentiometric titration, chemical analysis, IR, UV, XRD and TG-DTA. Complex impedance measurements show a high conductivity (5.44??10^?3 S/cm at 50??C), with an activation energy for proton conduction of 36.04 kJ/mol. The mechanism of proton conduction is the Vehicle mechanism.     

High-precision timing of the Quaternary standard samples with thermal ionization mass spectrometry (TIMS) U-series method

Two national stalagmite standard (GBW04412, GBW04413) and one international coral standard (RKM_4) have been determined by using thermal ionization mass spectrometry (TIMS) method. The values of ( 234 U/ 238 U) act , ( 230 Th/ 234 U) act and age are all consistent in error range with the standard values obtained by using α spectrometry.     

摩擦化学反应活化能对CMP的影响

根据质量作用定律,测定了铜膜在静态腐蚀和化学机械抛光（Chemical Mechanical Polishing,CMP）两种反应条件下的化学反应速率常数;通过Arrhenius方程,测定了铜膜在两种反应条件下的化学反应活化能.结果表明：当抛光液温度为298.15 K,工作压力为13 780 Pa时,静态腐蚀条件下体系化学反应速率常数是114.80 s^-1,而CMP条件下体系的化学反应速率常数是412.11 s^-1,同时,CMP条件下的反应活化能为4 849.80 J,静态腐蚀条件下的反应活化能为31 870.30 J,由此得出,反应活化能的降低是CMP过程中的机械摩擦作用所致.因此,根据CMP过程中铜膜和抛光垫各自克服滑动摩擦力所作的系统功,推导出CMP过程中活化能降低值的系统功表达式,并通过改变工作压力和转速来验证该表达式的适用性.     

全基因组关联分析显示基因ANXA8和C10orf11为影响肌少症的候选基因

为了寻找与瘦体重(lean body mass,LBM)相关的单核苷酸多态性(single nucleotide polymorphism, SNP)位点及易感基因,在1 000个不相关的白人中采用Affymetix 500K芯片扫描了500 000个SNPs,并进行全基因组关联分析(genome-wide association study,GWAS),显著结果在1 625个中国人样本和2 283个欧洲白人样本中进行验证,并将验证结果与研究结果进行荟萃分析。研究发现SNPsrs7905603,rs9416083,rs4409772,rs2894310与LBM关联,其中rs7905603位于基因ANXA8,其他3个SNPs位于基因C10orf11。荟萃分析得到的合并p值分别为2.08×10-5,7.44×10~(-6),6.73×10~(-6),6.76×10~(-6)。ANXA8和C10orf11基因是影响LBM变异的候选基因,这对肌少症的认识提供了新的理论依据。     

Single zircon dating by LAM-ICPMS technique

A UV laser ablation microprobe-inductively coupled plasma mass spectrometry (LAMICPMS) is used to determine the Pb/Pb and Pb/U ages of several zircon grains whose ages have been measured by the conventional U-Pb thermal ionization mass spectrometry (TIMS) method. The mass fractionation factor of Pb isotope ratio was typically between 0.010-0.012 and corrected by NIST610 glass standard. Several factors that influence the stability of Pb/U ratio have been investigated and optimized. The precision of²⁰⁷Pb/²⁰⁶Pb and²⁰⁶Pb/²³⁸U from each sampling crater is within 0.6%—2.4% and 1%—10% respectively, while the precision for the average of mean ratios from different craters is 0.7% and 6% correspondingly. The²⁰⁷Pb/²⁰⁶Pb and²⁰⁶Pb/²³⁸U age differences compared with TIMS results are ≪ 1% and < 3% respectively.     

勒庞与马克思的群体思想对我国群体性事件的启示

古斯塔夫.勒庞认为聚集在一起的群众是＂乌合之众＂,群众对于历史是被动的,是受众。而卡尔.马克思则认为历史是由人民大众经过长期努力创造的,并且肯定人民群众在社会中的作用,二者涉及到了一个共同问题———群体性事件。群体事件中存在严重的盲从现象且涉及多种社会矛盾,所以政府及相关部门应及时关注群众心理,以马克思主义的群体思想为指导,正确处理群体性事件。     

飞秒激光场中甲醇产物离子的角分布

利用直流切片离子成像技术结合飞行时间质谱技术,我们研究了甲醇(CH_3OH)分子在800 nm飞秒激光场中的多光子解离和库仑爆炸过程.获得了甲醇分子在光场中的飞行时间质谱和产物离子的切片影像,分析得到了不同库仑爆炸通道碎片离子的动能分布和角度分布.本文对比分析了C-O键断裂产生H_2O~+的H转移通道和产生OH~+的非H转移通道的角分布,计算了不同激光强度下两个通道的各向异性参数α_2和(cos~2θ),并根据产物离子角度分布与激光强度和离子价态的关系,揭示了甲醇分子在飞秒光场中的准直机制为动力学准直.     

甲状腺肿块的高频彩色多普勒超声诊断

目的 :探讨高频彩色多普勒超声检查对甲状腺肿块的诊断价值。方法 :对 48例甲状腺包块患者进行二维及彩色多普勒血流显像超声检查。结果 :48例甲状腺包块患者共检出肿块 67个 ,超声检查与病理对照除 3例误诊外 ,其余 45例与病理结果包括肿块部位、数目均符合 ,符合率 90 % ( 42 / 45 )。结论 :高频彩色多普勒超声检查对甲状腺肿块具有较高的诊断价值 ,可为临床提供有价值的诊断依据     

Potential release of hydrogen fluoride from domestic coal in endemic fluorosis area in Guizhou,China

Almost half of the total rural area of Guizhou Province and many regions within the 11 adjacent provinces in southwestern China have a long history(at least 70 years) of endemic fluorosis,including dental fluorosis and osteofluorosis along with its associated deformities and disabilities.Over decades of research,this specific type of endemic fluorosis has been defined as coal-burning fluorosis,which is distinct from drinking-water fluorosis.It is generally acknowledged that indoor burning and combustion of high-fluorine coal leads to food contamination,and fluorine then enters the human body.However,the exact chemical form of fluorine during its release and transfer to the body is still unknown.In the present study,21 domestic coal samples from outcrop and semi-outcrop coal collected in five villages with fluorosis were analyzed by time-of-flight secondary ion mass spectrometry(TOF-SIMS).The total mass fraction of sulfur in the samples ranged from 0.24%-5.58% and total fluorine content ranged 90.2-149.2 mg/kg.H3O+,H2SO4+ and HSO4-were detected in the samples by TOF-SIMS,which indicated that sulfuric acid hydrate(H2SO4.H2O) was present in the samples.F-was detected in all of these,which suggested the samples contain ionic fluorine compounds.Under certain circumstances,such as heating or burning,the prevalence and coexistence of the acid(H2SO4.H2O) and base(F-) would lead to a neutralization reaction producing volatile hydrogen fluoride(HF,bp = 19.5℃).This would be the chemical form of fluorine released from the coal.Further studies using HF and SO2 test tubes on headspace gas over coal samples heated to 200℃ in the laboratory and on headspace gas over stoves or chimney tops at rural residences confirmed the release of HF.     

用同位素稀释法测定牛肝和人血清中的锌和硒

结合阴离子交换树脂分离及巯基棉分离技术,采用同位素稀释-电感耦合等离子体质谱法测量了国际比对样品CCQM-K49牛肝样品和人血清样品中的锌和硒。结果表明,对于待测元素含量较高的样品,不经分离,高倍稀释可有效减少基体的干扰;而对待测元素含量较低的样品,则必须经过分离才能准确测量。CCQM-K49牛肝样品中锌和硒的质量分数分别为(179.8±1.2)×10^-6和(2.067±0.027)×10^-6,BW3215人血清标准物质中锌的质量分数为(1.164±0.024)×10^-6,国际比对IMEP-17人血清样品中硒的质量分数(0.0780±0.0014)×10^-6,测量结果均与比对的中心值接近,符合检测的要求。