Evidence for only minor contributions from bacteria to sedimentary organic carbon

Because their molecular signatures are often prominent in extracts of sediments, bacteria are thought to be important contributors to petroleum source beds. It has been shown recently, however, that abundances of biomarkers do not always reflect relative contributions to sedimentary organic carbon (Corg). The contribution of photosynthetic green sulphur bacteria to sediments can be assessed effectively because the diagenetic products of distinctive carotenoids from these organisms occur widely and their biomass is isotopically labelled, being enriched in 13C. We show here that, although sediments and oils from the Western Canada and Williston basins contain prominent biomarkers of photosynthetic bacteria, the absence of 13C enrichment in the total Corg requires that the bacterial contribution is in fact minimal. Although the importance of bacterial reworking of sedimentary debris cannot be doubted, we argue that our findings, when considered in conjunction with those from other settings, suggest that bacterial biomass may commonly represent only a minor component of total Corg in carbonaceous rocks.     

新奇有机化合物的合成

本文综述了近年来具有奇异结构的新有机化合物的合成,根据化合物的结构特征及性质大致可分四类:1、高张力化合物;2、多面体化合物;3、芳香化合物;4、其它.     

有机化合物的敏化光氧化反应

本文着重阐述了有机化合物的电子转移敏化光氧化反应机理。作者根据大量实验事实将这种反应机理中繁杂的次级过程进行了系统的分类,并试图从结构与机理的关系上加以阐述,取得了较好的结果。相信这种观点对新反应体系的研究将产生较大影响。     

Evidence for several waves of global transmission in the seventh cholera pandemic

Vibrio cholerae is a globally important pathogen that is endemic in many areas of the world and causes 3-5 million reported cases of cholera every year. Historically, there have been seven acknowledged cholera pandemics; recent outbreaks in Zimbabwe and Haiti are included in the seventh and ongoing pandemic. Only isolates in serogroup O1 (consisting of two biotypes known as 'classical' and 'El Tor') and the derivative O139 can cause epidemic cholera. It is believed that the first six cholera pandemics were caused by the classical biotype, but El Tor has subsequently spread globally and replaced the classical biotype in the current pandemic. Detailed molecular epidemiological mapping of cholera has been compromised by a reliance on sub-genomic regions such as mobile elements to infer relationships, making El Tor isolates associated with the seventh pandemic seem superficially diverse. To understand the underlying phylogeny of the lineage responsible for the current pandemic, we identified high-resolution markers (single nucleotide polymorphisms; SNPs) in 154 whole-genome sequences of globally and temporally representative V. cholerae isolates. Using this phylogeny, we show here that the seventh pandemic has spread from the Bay of Bengal in at least three independent but overlapping waves with a common ancestor in the 1950s, and identify several transcontinental transmission events. Additionally, we show how the acquisition of the SXT family of antibiotic resistance elements has shaped pandemic spread, and show that this family was first acquired at least ten years before its discovery in V. cholerae.     

大气总悬浮颗粒物中有机物的分析研究

用大流量总悬浮颗粒物(TSP)采样器采集济南市环境空气中的颗粒物,分析了济南市大气颗粒物上的有机物的种类及含量;用索氏提取器提取其中的有机物,用自制的硅胶柱分离纯化,将分离纯化后的各组分用气相色谱一质谱(GC-MS)联用技术做定性定量分析．结果表明,从大气总悬浮颗粒物中共分离出62种有机物,GC—MS定性了53种,占色谱总流出成分的85．2％．     

一种可吸附有机卤化物的测定方法

利用总有机碳分析仪的固体样品燃烧炉完成活性炭的燃烧,用硼砂溶液吸收产生的卤化氢,离子色谱仪测定卤化氢含量,从而得出可吸附有机卤化物的含量。可吸附有机氟化物（AOF）、有机氯（AOCl）和有机溴（AOBr）化物检出限分别为12μg、22μg、32μg／L,在0．05～1．5mg／L内有良好的线性相关性（R2〉0．995）,该方法测定AOF、AOCl、AOBr与理论值相差较小,偏差〈15％,是一种可行实用的分析方法,同时操作简单,方便,可为实验室节省购置专用可吸附有机卤化物分析仪的资金。     

Evidence for spin-charge separation in quasi-one-dimensional organic conductors

Interacting conduction electrons are usually described within Fermi-liquid theory, which states that, in spite of strong interactions, the low-energy excitations are electron-like quasiparticles with charge and spin. In recent years there has been tremendous interest in conducting systems that are not Fermi liquids, motivated by the observation of highly anomalous metallic states in various materials, most notably the copper oxide superconductors. Non-Fermi-liquid behaviour is generic to one-dimensional interacting electron systems, which are predicted to be Luttinger liquids. One of their key properties is spin-charge separation: instead of quasiparticles, collective excitations of charge (with no spin) and spin (with no charge) are formed, which move independently and at different velocities. However, experimental confirmation of spin-charge separation remains a challenge. Here we report experiments probing the charge and heat current in quasi-one-dimensional conductors--the organic Bechgaard salts. It was found that the charge and spin excitations have distinctly different thermal conductivities, which gives strong evidence for spin-charge separation. The spin excitations have a much larger thermal conductivity than the charge excitations, which indicates that the coupling of the charge excitations to the lattice is important.     

憎水有机物在土壤有机质中的吸附

针对憎水有机物在土壤有机质的非线性吸附行为还不完全清楚的状况,通过研究菲、萘和二甲苯等有机化合物在土壤,以及从其中分离出来的腐殖质、腐殖酸和碱提取后的土壤的吸附行为进行研究,讨论非线性吸附的机制.吸附等温线的非线性程度按如下顺序变化腐殖酸＜土壤＜腐殖质＜碱提出土.脂肪碳富集的腐殖质的等温吸附行为表现出很强的吸附亲和性含量以及高的非线性.文章最后采用了无定型脂肪碳的固结概念模式来解释这些吸附行为.     

Several oxygenated monoterpenes from petals of Rosa damascena

Aim To discover the oxygenated monoterpenes that play a critical role in the biosynthetic pathway of monoterpene in Rosa damascene.Method Several kinds of isolation techniques such as liquid-liquid partition,silica column chromatography,thin layer chromatography and high performance liquid chromatography were used to separate the compounds and several identification techniques such as GC-MS and 1H-NMR were used to determine the structure of the isolated compounds.Results Three oxidized acyclic monoterpenes were obtained.They are 8-hydroxygeraniol,8-hydroxynerol and 8-hydroxylinalool.Conclusion The compounds are the important materials of pharmaceutical,cosmetic and food industries.The work has not only provided a new method for the determination of the main aromatic components of Rosa damascena,but also built up an important foundation for the study of biosynthesis of monoterpenoids in the plant.     

川西拗陷中段蓬莱镇组物源的地球化学示踪

探讨川西拗陷中段上侏罗统蓬莱镇组物源问题。采用地球化学示踪方法,通过岩石薄片、痕量元素和稀土元素等综合分析,结合前人的研究成果,对蓬莱镇组源区背景属性和物源特征进行研究。结果表明:研究区蓬莱镇组砂岩碎屑组分以石英为主,其次是长石及各种岩屑;REE配分模式与大陆上地壳稀土元素配分模式基本一致,轻稀土元素富集,Eu负异常较为明显。其源区的构造环境是从海相过渡到陆相,最后演化成复杂的源区。川西拗陷中段蓬莱镇组有龙门山、大巴山-米仓山多个物源区,北部的主要物源区为大巴山-米仓山,南部的物源区为龙门山,中部则为混源区。     

活性炭纤维在挥发性有机废气处理中的应用

因活性炭纤维比普通活性炭性能优异、吸附量大，吸附脱附速度快，因此被应用于挥发性有机废气中苯系物、醋酸丁酯、甲醇等的吸附．介绍了活性炭纤维的分类、制备工艺、结构和性能．并展望了活性炭纤维在环保领域挥发性有机废气处理中的应用前景．     

有机化合物爆炸下限的预测

根据化学热力学原理和爆轰原理,探讨了有机化合物的爆炸下限与燃烧热之间的定量关系,提出一种预测有机物爆炸下限的方法,计算结果表明,预测值和实验值非常吻合,平均误差0.18%,该方法不仅能够预测有机化合物的爆炸下限,而且有助于揭示爆炸下限与燃烧热之间的定量关系。     

Evidence for deep-water production in the North Pacific Ocean during the early Cenozoic warm interval

The deep-ocean circulation is responsible for a significant component of global heat transport. In the present mode of circulation, deep waters form in the North Atlantic and Southern oceans where surface water becomes sufficiently cold and dense to sink. Polar temperatures during the warmest climatic interval of the Cenozoic era (approximately 65 to 40 million years (Myr) ago) were significantly warmer than today, and this may have been a consequence of enhanced oceanic heat transport. However, understanding the relationship between deep-ocean circulation and ancient climate is complicated by differences in oceanic gateways, which affect where deep waters form and how they circulate. Here I report records of neodymium isotopes from two cores in the Pacific Ocean that indicate a shift in deep-water production from the Southern Ocean to the North Pacific approximately 65 Myr ago. The source of deep waters reverted back to the Southern Ocean 40 Myr ago. The relative timing of changes in the neodymium and oxygen isotope records indicates that changes in Cenozoic deep-water circulation patterns were the consequence, not the cause, of extreme Cenozoic warmth.     

有机化合物粘度的定量构性关系研究

本文对177个有机化合物,用HyperChem 6．0软件中分子力学方法MM^＋进行几何结构优化并经构象搜寻得到了最低能量构象的几何结构,并通过分子描述符软件计算了表征分子的电子、拓扑、几何结构的共102分子个描述符,用偏最小二乘法（PLS）建立其粘度定量构性关系（QSPR）．本文采用Monte Carlo模拟退火方法进行变量筛选,最终筛选出14个描述符．模型验证采用了留一法．所建立的最后的最优模型的结果为：Q^2=0．85,R^2=0．87,表明该模型具有较好的预测能力．     

抗挥发性有机化合物沾染织物的加工工艺研究

某些工厂的作业环境中充满了挥发性有机化合物气体,在这种环境中工作的人员必须穿着具有一定防护功能的服装,以防止这些挥发性特质对健康造成损害.本文探讨抗挥发性有机化合物沾染织物的加工工艺.给出了几种加工整理方法,以减少服装面料对挥发性有机物质的沾染.包括使用不同的纤维材料制作织物,减少织物的面密度,织物与PTFE微孔膜复合,以及使用含氟整理剂或有机硅整理剂整理织物等.实验中,使用上述方法加工的织物暴露在富含挥发性有机化合物合溶胶的氛围中24h,然后取出用二硫化碳萃取织物上粘附的有机化合物,利用气相色谱分析技术检测其含量.检测结果显示,不同纤维制作的面密度相同的织物,对各种挥发性有机物质的染性能差别不大.但是,通过降低织物的面密度,或者将织物与唧微孔膜复合,或者使用含氟整理剂或有机硅整理织物,均可有效降低织物对挥发性有机化合物的沾染.     

Evidence for decoupling of atmospheric CO2 and global climate during the Phanerozoic eon

Atmospheric carbon dioxide concentrations are believed to drive climate changes from glacial to interglacial modes, although geological and astronomical mechanisms have been invoked as ultimate causes. Additionally, it is unclear whether the changes between cold and warm modes should be regarded as a global phenomenon, affecting tropical and high-latitude temperatures alike, or if they are better described as an expansion and contraction of the latitudinal climate zones, keeping equatorial temperatures approximately constant. Here we present a reconstruction of tropical sea surface temperatures throughout the Phanerozoic eon (the past approximately 550 Myr) from our database of oxygen isotopes in calcite and aragonite shells. The data indicate large oscillations of tropical sea surface temperatures in phase with the cold-warm cycles, thus favouring the idea of climate variability as a global phenomenon. But our data conflict with a temperature reconstruction using an energy balance model that is forced by reconstructed atmospheric carbon dioxide concentrations. The results can be reconciled if atmospheric carbon dioxide concentrations were not the principal driver of climate variability on geological timescales for at least one-third of the Phanerozoic eon, or if the reconstructed carbon dioxide concentrations are not reliable.     

纺织品中挥发性有机物的测定

采用大体积顶空固相微萃取-气相色谱/质谱联用技术,建立测定纺织品中总挥发性有机物、总芳香烃化合物和4种单体(甲苯、乙烯基环己烯、苯乙烯、4-苯基环己烯)的方法.对测试条件进行优化,包括萃取头的选择、萃取、解析、色谱等条件.结果表明:所建方法对甲苯、乙烯基环己烯、苯乙烯、和4-苯基环己烯的检出限低于0.001 mg/m2,回收率93.5%~107.8%.     

Labeling of volatile organic compounds emissions from Chinese furniture: Consideration and practice

Volatile organic compounds (VOCs) emitted from furniture are recognized as a main cause of bad indoor air quality. In European countries and the U.S., labeling systems for furniture have been established with good effect to address this issue. However, there are problems with these labeling systems. For example, too many VOCs were targeted, and the testing time was too long (7–28 d). Aiming at solving these problems, solutions are put forward to establish furniture VOCs emissions labeling system in China and some practices are introduced in this paper. They are: some furniture popular in the market were tested and main VOCs emitted from these furniture were identified; furniture loading factors in residential homes were surveyed, and reference bedroom and reference living room were established according to the survey results to make emission rate thresholds of furniture; C-history method was developed and applied to testing furniture which could shorten the testing time to 3 d; a reference toluene sample for assessing the precision of the test results of chamber system was prepared. These works are technically helpful for establishing furniture VOCs labeling system in China.     

Influence of the Gulf Stream on the troposphere

The Gulf Stream transports large amounts of heat from the tropics to middle and high latitudes, and thereby affects weather phenomena such as cyclogenesis and low cloud formation. But its climatic influence, on monthly and longer timescales, remains poorly understood. In particular, it is unclear how the warm current affects the free atmosphere above the marine atmospheric boundary layer. Here we consider the Gulf Stream's influence on the troposphere, using a combination of operational weather analyses, satellite observations and an atmospheric general circulation model. Our results reveal that the Gulf Stream affects the entire troposphere. In the marine boundary layer, atmospheric pressure adjustments to sharp sea surface temperature gradients lead to surface wind convergence, which anchors a narrow band of precipitation along the Gulf Stream. In this rain band, upward motion and cloud formation extend into the upper troposphere, as corroborated by the frequent occurrence of very low cloud-top temperatures. These mechanisms provide a pathway by which the Gulf Stream can affect the atmosphere locally, and possibly also in remote regions by forcing planetary waves. The identification of this pathway may have implications for our understanding of the processes involved in climate change, because the Gulf Stream is the upper limb of the Atlantic meridional overturning circulation, which has varied in strength in the past and is predicted to weaken in response to human-induced global warming in the future.