56 resultados para Zhejiang
em Chinese Academy of Sciences Institutional Repositories Grid Portal
Resumo:
This study was conducted to measure the levels of 23 PCB congeners and 6 organochlorine pesticides (OCPs) in human milk and three food types collected from Luqiao and Pingqiao in Zhejiang Province, China. An effort was also made to explore the potential health risk for the mothers and breast-fed infants living in these two localities. Luqiao was selected as the sampling site because it is the largest place for the disassembly of obsolete transformers and electrical waste in China. Pingqiao, located 100 kin NW of Luqiao, is not known to be a place for any electronic or electrical waste and hence was chosen as the control site. Both localities are important agricultural places in the province. The organochlorines were measured in the samples using the GC-PECD technique. Micro-EROD bioassay method was also used as a complement of the chemical analysis to estimate the TEQ levels of dioxin-like PCBs in human milk. The data showed that the human milk, rice, hen egg, and fish samples from Luqiao were more heavily contaminated with PCBs than those from Pingqiao, suggesting that the mothers and their breast-fed infants in Luqiao tended to receive greater exposure to PCBs than those living in Pingqiao. The OCP levels in the two localities were found comparable, suggesting that the major source of contamination with these pesticides was from their agricultural uses. Significant correlation (R-2 = 0.87, P < 0.001) of PCB TEQs was found between the bioassay and chemical analysis method, suggesting that micro-EROD is an effective method for comprehensive determination of TEQ levels in human milk. Comparison with literature data showed that the PCB levels in milk samples from Luqiao were significantly higher than those from localities in other Chinese provinces and comparable to those in developed or industrialized countries. (c) 2007 Published by Elsevier B.V.
Resumo:
Prenatal exposures to persistent organic pollutants were assessed using the levels of PCBs and organochlorine pesticides (OCPs) measured in cord blood and meconium samples from Luqiao and two other localities of the Zhejiang province in China. Luqiao is a town with the largest site for disassembly of PCB-containing obsolete transformers and electrical waste in China. The other two localities Pingqiao (100 km NW of Luqiao) and Lin'an (500 km NW of Luqiao) are towns without known electronic or electrical waste sites. A total of 23 PCB congeners (including 12 dioxin-like) and 6 OCPs were measured using the traditional GC-mu ECD technique. Micro-EROD bioassay was additionally used to measure TCDD-based TEQ levels of the 12 dioxin-like PCBs. Significant correlations were found between the TEQs measured by the two methods, supporting the application of micro-EROD as a practical toot for complementing the chemical analysis. The data showed that beta-HCH, p,p'-DDE, and 6 PCB congeners (101, 138 153, 180, 183, and 187) were the predominant pollutants, with PCB 138 being the best indicator (predictor) for total PCB levels. Cord blood and meconium from Luqiao have higher levels of PCBs than those from the other two localities, suggesting that a disassembly site for electronic and electric waste would provide an environment for greater exposure to these chemicals. The cord blood or meconium levels of beta-HCH, though likewise considerably high, were comparable in the three localities. Similar findings were observed for p,p'-DDE. Pollution by these OCPs might have come from past use of agricultural pesticides in the three localities. (c) 2007 Published by Elsevier B.V.
Resumo:
Fifty-one phytoplankton samples were collected from different ecological environments in five provinces located in the central, eastern and southwestern parts of China. 41 taxa of silica-scaled chrysophytes, 8 of them belonging to the Chrysophyceae and 33 to the Synurophyceae, have been identified by means of electron microscopy. Among them, Mallomonas parvula, M. calceolus, M. cyathellata (?), M. costata, M. crassisquama, and Synura echinulata are new to China. The silica-scaled chrysophyte flora and its geographical distribution in this region are analysed and discussed.
Resumo:
MASNUM wave-tide-circulation coupled numerical model (MASNUM coupled model, hereinafter) is developed based on the Princeton Ocean Model (POM). Both POM and MASNUM coupled model are applied in the numerical simulation of the upwelling off Yangtze River estuary and in Zhejiang coastal waters in summer. The upwelling mechanisms are analyzed from the viewpoint of tide, and a new mechanism is proposed. The study suggests that the tidally inducing mechanism of the upwelling includes two dynamic aspects: the barotropic and the baroclinic process. On the one hand, the residual currents induced by barotropic tides converge near the seabed, and upwelling is generated to maintain mass conservation. The climbing of the residual currents along the sea bottom slope also contributes to the upwelling. On the other hand, tidal mixing plays a very important role in inducing the upwelling in the baroclinic sea circumstances. Strong tidal mixing leads to conspicuous front in the coastal waters. The considerable horizontal density gradient across the front elicits a secondary circulation clinging to the tidal front, and the upwelling branch appears near the frontal zone. Numerical experiments are designed to determine the importance of tide in inducing the upwelling. The results indicate that tide is a key and dominant inducement of the upwelling. Experiments also show that coupling calculation of the four main tidal constituents(M-2, S-2, K-1, and O-1), rather than dealing with the single M-2 constituent, improves the modeling precision of the barotropic tide-induced upwelling.
Resumo:
REE geochemistry data from the Fanshan alunite deposit indicated that its ore-forming materials came chiefly from the country rocks, with δCe〉0 for alunite ores. According to the differences in δEu, the alunite ores were divided into three types: weak negative Eu anomaly, weak positive Eu anomaly and remarkable positive Eu anomaly. The phenomena of Ce-enrichment in the ores indicated that the Fanshan alunite deposit was formed in an oxidizing environment. Variations in fO2 are corresponding to those in δEu: Eu anomaly varies from negative to positive with increasing fO2. And two other important factors may impact the occurrence of Eu anomalies: the contents of alkaline feldspar and the protolith structure in the mineralization period.
Resumo:
The recent progress of submerged floating tunnel (SFT) investigation and SFT prototype (SFTP) project in Qiandao Lake (Zhejiang Province, P.R. China) is the background of this research. Structural damping effect is brought into present computation model in terms of Rayleigh damping. Based on the FEM computational results of SFTPs as a function of buoyancy-weight ratio (BWR) under hydrodynamic loads, the effect of BWR on the dynamic response of SFT is illustrated. In addition, human comfort index is adopted to discuss the comfort status of the SFTP.
Resumo:
上新世时期是地球环境发展变化过程中由温暖的中新世向冰期-间冰期交替出现的更新世的过渡时期,研究上新世的气候有助于研究现代全球气候变化趋势。我国上新世植物群研究不多,尤其缺乏早上新世植物群的研究。在研究化石植物群的过程中,叶角质层的信息通常被忽视。迄今,我国古气候的定量研究主要集中在山东山旺和云南地区,研究的主要是中新世和晚上新世的古气候,早上新世气候的定量研究国内外都未见报道。 本论文以采自浙江中部嵊州地区硅藻土中的植物叶和果实为材料,通过光学显微镜、荧光显微镜和扫描电镜观察,对提取的化石叶角质层和叶结构进行研究,对比研究现代相关类群植物的叶片,确定了化石植物类群计15科24属(或亚科)34种。同时参照现代植物分布,恢复了早上新世嵊州地区古植被情况,进一步运用共存分析(Co-existence Approch)定量重建了当时的古气候,得到古年均温、古年较差和古年降水量等7个参数。 研究表明,叶结构和叶角质层可以应用于化石植物类群的鉴定。光学显微镜和荧光显微镜下可以获得的信息有:气孔、表皮细胞形状及大小、表皮细胞垂周壁、分泌结构、表皮毛或毛基等。扫描电镜观察的是叶表皮细胞表面的情况,如细胞外壁是否被蜡质以及蜡质的交结情况,气孔外壁是否增厚呈环等。 经化石植物类群鉴定,早上新世(约4Ma)嵊州地区植被属亚热带常绿阔叶林。推测:该地区当时存在一个较大的湖泊,湖泊边缘水中生长有菱角,湖泊周边可能有海拔超过1400m的山地。 常绿阔叶林主要成分是壳斗科植物,其中青冈属植物可能是建群植物。自低海拔到高海拔地区都有分布的是:栎属、栗属、桤木属植物,青杨梅。低海拔地区(<600m)分布的植物有:海南锥,樟。中低海拔地区(300-1000m)分布着:柯属、黄杨属植物,水青冈,海南油丹,江南油杉,福建柏。中高海拔地区(>700m)分布有:高山栎、黄肉楠属植物,米心水青冈,榉树,建始槭,天台鹅耳枥和昌化鹅耳枥。除了上述类群,林中还散布着鼠李属、杜鹃花属和冬青属的植物,豆科崖豆藤属植物则缠绕一些较大乔木生长。另外,在一些土壤、有机质易堆积的洼地生长有竹林,山地贫瘠的地方生长着柏属植物。 嵊州早上新世化石植物群反映的植被同浙江地区现代植被相似。第三纪浙江地区从针叶林或阔叶树为主的针-阔叶混交林过渡到常绿-落叶阔叶林,再发展为常绿阔叶林。 依据23个植物类群分析获得7个古气候参数:年均温17.7-21.4°C,最热月均温22.2-27°C,最冷月均温8.4-13.4°C,年较差12.1-15.3°C,年降水量1136-1869.9mm,最大月降水量211.8-283.3mm,最小月降水量20.3-36.8mm。 对比现代嵊州地区气候参数,早上新世嵊州地区年降水量略高于现代,年均温比现代高1.3-5°C,年较差为12.1-15.3°C。早上新世期嵊州地区四季气温比现代平稳。
Resumo:
本研究以河北围场县广发永化石点早中新世地层中的球果和果实、浙江宁海县杜岙化石点早上新世地层中的半矿化化石木、云南寻甸县金所和先锋化石点晚上新世地层中的丝炭和褐煤化木材为研究对象,对这三个化石点数百个植物大化石的形态或解剖结构进行了详细研究,鉴定出6个新的化石种,4个新记录种,7个未定种;其中2个化石属为我国新记录。根据其结构特征探讨这些化石类群与相关化石和现代植物的系统关系。并依据其现代亲缘种生长的生态和气候范围,对化石点沉积时期的植被和气候类型进行了推测。 果实中含有多种有价值的分类和系统发育的信息,对于种子植物的演化和系统发育研究具有重要的意义。在河北围场县发现大量保存较好的松科球果和姜科化石,为我们进一步研究松科植物和姜科植物解剖结构,以及探讨其系统演化提供难得的机会和直接的证据,同时为该化石地的植被演替和地层对比研究提供更多的植物学证据。对河北围场县广发永化石点球果和果实的形态研究,鉴定出三种松科球果化石种和一种姜科植物。分别为围场松(Pinus weichangensis sp. nov.)、围场云杉(Picea weichangensis sp. nov.)、围场铁杉(Tsuga weichangensis sp. nov.)以及化石Spirematospermum属未定种。其中围场云杉、围场铁杉球果在形态上与相应现代类群具有明显的差异,可能代表已灭绝的种类。Spirematospermum属未定种为一绝灭类型,是该属在我国的首次记录。这四种化石类群发现,反映早中新世化石该化石点气候与现代完全不同,为湿润的暖温带和亚热带气候。 浙江省在地质结构上位于东亚大陆边缘,是环太平洋岩浆活动带的重要组成部分。宁海县属于浙东南区属华南地层区,其第三纪地层嵊县群在该区分布广泛,其古植物研究仅限于孢粉和叶化石。本报告中首次对该层铜岭祝组的木化石进行了报道。对浙江宁海杜岙化石点早上新世地层中化石木样品的解剖研究,鉴定出三种木材类型,为史马库栎型木Quercus shimakurae、Liqumdambar cf. hisauchi和蔷薇科未定种。前者与现代栎属槲栎类、后者与枫香树属分别具有密切的亲缘关系,是我国首次报道栎属和枫香树属化石木。 云南现今复杂的地势地貌,独特的气候,丰富的植物种类和多样的植被类型是经历了长达数百万年的地质构造运动和自然环境演变的结果。第三纪时期由于大陆板块运动导致印度板块与亚洲板块的对接和碰撞,其地壳构造运动异常活跃。其第三系陆相地层广泛分布于古生代褶皱区的200多个互不相连的中、小型盆地及中、新生代断陷和拗陷型山间盆地中,并蕴涵了丰富的植物化石,为我们研究植被和植物演化提供了众多的证据。本次研究基于云南中部寻甸县金所煤矿和先锋煤矿的大量褐煤化和丝炭化材料,为进一步恢复云南晚第三纪气候和植被提供更多的依据,尤其是丝炭材料保存了木材精细而真实的结构,为木材准确鉴定和演化提供了可靠的依据。根据对云南金所和先锋化石点晚上新世沉积中褐煤化材料和丝炭样品解剖结构的研究,鉴定出8种化石木,包括2种裸子植物,5种双子叶植物和1种单子叶植物;分属5科7属。化石类群包括松属(Pinus)五针松组未定种Section Cembra sp.、云杉属未定种Picea sp、寻甸含笑Michelia xundianensis sp. nov.、多角含笑 Michelia angulata sp. nov.、Lithocarpoxylon cf. radiporosum、Castanoradix sp.、寻甸珍珠花Lyonia xundianensis sp. nov.、竹亚科未定种Bambusoideae sp。根据现今这些化石对应类群的生长和分布的气候区域,沉积时期的气候与现代气候较为接近。
Resumo:
物种共存机制一直是群落生态学研究的核心内容。解释物种共存的假说很多,近年来最引人注目的是生态位分化假说和群落中性理论。这两种理论对群落内物种共存的相对重要性是目前群落生态学研究的热点。国际上这方面的研究基本集中在热带森林大样地内,而针对亚热带森林大样地的相关研究却非常少见。本文以浙江古田山24公顷常绿阔叶林永久固定监测样地第一次调查数据为基础,研究样地内木本植物与生境关联和与地形因子梯度相关,目的在于探讨物种生境生态位分化在亚热带常绿阔叶林内物种多样性维持中的作用,也为了解决当前物种生境关联相关研究中的一些不足之处。 本研究首先采用Torus转换检验分析古田山样地内90种常见木本植物与5类生境关联,结果表明有75种(83.3%)至少与一类生境类型显著相关,说明大部分亚热带森林群落内物种具有生境特化的特性。与CTFS全球大样地类似研究结果相比,古田山样地内生境特化的物种比例更高,这与古田山样地复杂的地形条件密切相关。通过本研究,证明地形条件越复杂,物种特化比例越高的趋势确实存在。在古田山样地,虽然83.3%的物种有生境特化的特性,但生境特化没有排他性,即并不完全排斥其他生境,在非最适生境也能稳定与其他物种共存。根据本研究与生境负相关的平均物种数与被检测的物种比例估算,古田山样地内生境异质性对物种多样性维持的贡献率约为19.6%,说明物种生境特化对于物种共存有一定的作用,但贡献并不大,除了生境异质性,仍有其他因素决定物种共存。 目前有关物种生境关联的研究都假设同一物种的个体对于生境偏好一致,不管胸径大小是否相同,很少有人研究不同生长阶段生境偏好的变化。本研究利用Torus转换检验比较样地内60种常见木本植物在3个生活史阶段(幼苗阶段、小树阶段和成熟阶段)与5类生境关联的变化,结果表明大部分物种在其幼苗和小树阶段的生境偏好比较一致,但成熟阶段与前两个阶段差别比较大,说明物种在生活史不同阶段的生境偏好可能发生改变。 由于生境划分没有统一的标准,不同学者用不同的方法划分生境类型和数量,主观性很大,造成不同研究地点、不同研究者之间的研究结果可比性差。本研究尝试利用直接梯度分析方法重新分析物种空间分布与地形梯度相关,用以代替生境关联分析。利用CCA分析检验样地内90种常见木本植物与4种地形因子梯度(海拔、凹凸度、坡度和坡向)的相关情况,发现有76个(84%)物种的空间分布与地形梯度相关,说明大部分物种具有沿地形因子梯度分布的特性。4种地形因子梯度变化对90个物种空间分布的解释量约为20%,说明地形异质性对于物种共存有一定作用,但贡献并不大。对生境关联分析和直接梯度法分析结果进行比较,两种方法分析结果一致,得到的结论也一致。直接梯度分析方法可以避免生境划分对研究结果的影响,是今后类似研究中值得采纳的方法。 本研究的结果表明地形异质性引起的生态位分化在古田山样地群落内物种多样性维持中起一定的作用,但贡献不大,因此需要更深入地研究其他环境因素引起的生态位分化在物种多样性维持中的作用,同时也需要进一步研究中性过程在物种多样性维持中的作用,以更全面地探讨生态位分化假说和中性理论在亚热带常绿阔叶林内物种共存的相对重要性。
Resumo:
The genetic diversity and phylogeny of 26 isolates of Bursaphelenchus xlophilus from China, Japan, Portugal and North America were investigated based on the D2/3 domain of 28S rDNA, nuclear ribosomal Internal Transcribed Spacer (ITS) sequences, and random amplified polymorphic DNA (RAPD) analysis. The genetic diversity analysis showed that the D2/3 domain of 28S rDNA of isolates of B. xlophilus from China, Portugal, Japan and the US were identical and differed at one to three nucleotides compared to those from Canada. ITS sequences of isolates from China and Portugal were the same; they differed at one or two nucleotides compared to those of Japanese isolates and at four and 23 nucleotides compared to those front the US and Canada, respectively. The phylogenetic analysis indicated that Chinese isolates share a common ancestor with one of the two Japanese clades and that the Canadian isolates form a sister group of the clade comprised of isolates from China, Portugal,Japan, and the US. The relationship between Japanese isolates and those from China was closer than with the American isolates. The Canadian isolates were the basal group of B. xylophilus. This suggests that B. xlophilus originated in North America and that the B. xylphilus that occurs in China could have been first introduced from Japan. Further analysis based on RAPD analysis revealed that the relationship among isolates from Guangdong, Zhejiang, Shandong, Anhui provinces and Nanjing was the closest, which suggests that pine wilt disease in these Chinese locales was probably dispersed from Nanjing, where this disease first occurred in China.
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In the present study, EA-CATH1 and EA-CATH2 were identified from a constructed lung cDNA library of donkey (Equus asinus) as members of cathelicidin-derived antimicrobial peptides, using a nested PCR-based cloning strategy. Composed of 25 and 26 residues, respectively, EA-CATH1 and EA-CATH2 are smaller than most other cathelicidins and have no sequence homology to other cathelicidins identified to date. Chemically synthesized EA-CATH1 exerted potent antimicrobial activity against most of the 32 strains of bacteria and fungi tested, especially the clinically isolated drug-resistant strains, and minimal inhibitory concentration values against Gram-positive bacteria were mostly in the range of 0.3-2.4 mu g center dot mL-1. EA-CATH1 showed an extraordinary serum stability and no haemolytic activity against human erythrocytes in a dose up to 20 mu g center dot mL-1. CD spectra showed that EA-CATH1 mainly adopts an alpha-helical conformation in a 50% trifluoroethanol/water solution, but a random coil in aqueous solution. Scanning electron microscope observations of Staphylococcus aureus (ATCC2592) treated with EA-CATH1 demonstrated that EA-CATH could cause rapid disruption of the bacterial membrane, and in turn lead to cell lysis. This might explain the much faster killing kinetics of EA-CATH1 than conventional antibiotics revealed by killing kinetics data. In the presence of CaCl2, EA-CATH1 exerted haemagglutination activity, which might potentiate an inhibition against the bacterial polyprotein interaction with the host erythrocyte surface, thereby possibly restricting bacterial colonization and spread.
Resumo:
This study is one of the very few investigating the dioxin body burden of a group of child-bearing-aged women at an electronic waste (e-waste) recycling site (Taizhou, Zhejiang Province) (24 +/- 2.83 years of age, 40% were primiparae) and a reference site (Lin'an city, Zhejiang Province, about 245 km away from Taizhou) (24 +/- 2.35 years of age, 100% were primiparae) in China. Five sets of samples (each set consisted of human milk, placenta, and hair) were collected from each site. Body burdens of people from the e-waste processing site (human milk, 21.02 +/- 13.81 pg WHO-TEQ(1998/g) fat (World Health Organization toxic equivalency 1998); placenta, 31.15 +/- 15.67 pg WHO-TEQ(1998/g) fat; hair, 33.82 +/- 17.74 pg WHO-TEQ(1998/g) dry wt) showed significantly higher levels of polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurnas (PCDD/Fs) than those from the reference site (human milk, 9.35 +/- 7.39 pg WHO-TEQ(1998/g) fat, placenta, 11.91 +/- 7.05 pg WHO-TEQ(1998/g) fat; hair, 5.59 +/- 4.36 pg WHO-TEQ(1998/g) dry wt) and were comparatively higher than other studies. The difference between the two sites was due to e-waste recycling operations, for example, open burning, which led to high background levels. Moreover, mothers from the e-waste recycling site consumed more foods of animal origin. The estimated daily intake of PCDD/Fs within 6 months by breast-fed infants from the e-waste processing site was 2 times higher than that from the reference site. Both values exceeded the WHO tolerable daily intake for adults by at least 25 and 11 times, respectively. Our results implicated that e-waste recycling operations cause prominent PCDD/F levels in the environment and in humans. The elevated body burden may have health implications for the next generation.