基于粗糙集的数据挖掘算法的研究

粗糙集理论是一种新的处理模糊和不精确问题的重要数学工具,是一种新的数据挖掘技术。本文主要研究基于粗糙集的数据挖掘的算法在规则提取阶段的应用。     

On the systematics,distribution and conservation status of Ichthyophis longicephalus Pillai, 1986 (Amphibia: Gymnophiona: Ichthyophiidae)

The caecilian Ichthyophis longicephalus was described in 1986 based on a single specimen. Only one specimen has been referred subsequently to this species, and the validity of that referral has been questioned. Seven specimens discovered in 2009–2010 at two new localities and two specimens collected in 1990 from a third locality are referred here to I. longicephalus. These specimens are described and compared with the poorly preserved holotype. Mitochondrial DNA data are consistent with the interpretation that the new specimens represent a single species distinct from (and most closely related to I. tricolor among) sampled congeners. The previously referred specimen, from c. 320 km south of the type locality, is not I. longicephalus and probably represents an undescribed species. The “rediscovery” of I. longicephalus in forests and disturbed habitats indicates that the species probably could be transferred from the Data Deficient to the Least Concern category of the IUCN Red List.     

Integrative taxonomic analysis reveals a new species of Leptobrachium (Anura: Megophryidae) from north-eastern Cambodia and central Vietnam

ABSTRACT

Species boundaries within the red-eyed Leptobrachium of southern Indochina have been uncertain. Leptobrachium pullum and L. mouhoti from upper and lower elevations, respectively, of the Langbian Plateau of southern Vietnam and eastern Cambodia differ in body size but have relatively low interspecific mitochondrial DNA divergence, leading to speculation that these might represent a single species with an elevational cline in body size. The recent discovery of an allopatric high-elevation population of red-eyed Leptobrachium on the Kon Tum Plateau (= Central Highlands) of north-eastern Cambodia and central Vietnam has been referred to both species, and to a putatively undescribed species. We examine variation in morphology of adults and tadpoles, mitochondrial DNA, 11 nuclear genes and advertisement calls, and show corroborating lines of evidence for the existence of three species of red-eyed Leptobrachium in southern Indochina. Although the three species are reciprocally monophyletic in mitochondrial DNA, their shallow mitochondrial DNA divergences are not mirrored by morphology, advertisement calls, or – in part – nuclear DNA, and probably reflect past mitochondrial introgression rather than recent speciation. The Central Highlands taxon is described herein as a new species.

http://www.zoobank.org/urn:lsid:zoobank.org:pub:CE6650AF-D9FB-40F4-8A2E-9B4E23AAC205     

Zn2+对硫酸长春碱抗癌活性影响研究

利用荧光光谱法、紫外光谱法和黏度法研究了Zn2+对硫酸长春碱与DNA的结合模式、结合常数的影响.研究结果表明,在有无Zn2+存在的情况下,硫酸长春碱与DNA均以氢键和范德华作用力结合,Zn2+的加入使硫酸长春碱与DNA的作用模式由沟槽结合转为嵌入式结合,同时反应的结合常数随Zn2+浓度增大而增大,反应的吉布斯自由能变变小,说明Zn2+对硫酸长春碱与DNA的结合起促进作用,这可能是由于Zn2+和硫酸长春碱形成络合物,又通过水合分子以氢键与DNA上的碱基对结合,加快了硫酸长春碱-DNA体系间的电子传递.由于部分抗癌药物的抗癌机理主要是药物与癌细胞DNA相互作用,抑制癌细胞的繁殖,可以判断出Zn2+的参与可能增强了硫酸长春碱的抗癌活性.     

散射/荧光比率法测定核酸

在pH 9.62的BR缓冲溶液中,阳离子染料吖啶橙(AO)与鱼精DNA(fsDNA)通过静电作用形成二元复合物,导致AO在激发波长272 nm处产生增强的散射光,而在发射波长534 nm处出现荧光猝火.利用共存的散射和荧光信号,提出了一种散射/荧光比率法.在激发波长为272 nm和发射波长为534 nm的条件下,其散射/荧光比值(I/F)和0.02～1.40 μg,/mL范围内的fsDNA溶液成一定的线性关系,据此测定核酸的含量,其检出限为5.7 ng/mL.此方法成功用于核酸合成样的测定,RSD为1.3%-2.0%.实验结果表明,比率法比单波长的散射法或荧光法灵敏度更高,线性范围更宽.     

不同价态的阴离子在DNA凝聚效应中的抑制作用

为了定量地研究阴离子对DNA凝聚和电荷中和过程的抑制作用，利用动态光散射和原子力显微镜研究了不同价态阴离子对阳离子介导的DNA凝聚效应的影响。在动态光散射实验中，阴离子可以使阳离子作用后的DNA的电泳迁移率变小，即对DNA的电荷中和有抑制作用，而且阴离子价态越高，对电泳迁移率的抑制作用越强。改变阳离子种类但控制相同的阳离子浓度，发现阴离子对DNA的电荷中和有同样的抑制作用及趋势，同时用原子力显微镜观察DNA的凝聚形态变化也得出一致的结果。在相同阳离子浓度下，高价阴离子相对低价态阴离子，对DNA凝聚的抑制作用更强，使DNA的凝聚形态变得更加松散，进一步证实了阴离子对阳离子导致的DNA凝聚有减弱作用。     

直接法提 取血清DNA后套式聚合酶链反应扩增乙肝病毒DNA

为进一步提高ＨＢＶＤＮＡ检测水平，改良了直接法提取血清ＤＮＡ技术，并用套式聚合酶链反应扩增ＨＢＶＤＮＡ。即以裂解液直接提取血清ＨＢＶＤＮＡ，用内外两对引物分别进行连续两次扩增。     

光谱法研究阿米卡星与DNA的相互作用

在pH 6.O的Tris-HC1介质中,以溴化乙锭为荧光探针,研究了阿米卡星与小牛胸腺DNA之间的相互作用.采用荧光光谱、吸收光谱、Scatchard方程、圆二色谱、黏度等手段,对作用机理进行了研究,结果表明阿米卡星与小牛胸腺DNA之间的作用方式为混合方式,嵌入与沟槽作用是两种主要作用方式.求得25℃时的结合常数为2.2×104L·mo1-1.     

基于PFP荧光共振能量转移原理检测氧化损伤DNA

提出一种基于水溶性共轭聚合物PFP荧光共振能量转移原理检测氧化损伤DNA的方法。通过加入DNA修复酶来识别并切除被氧化的DNA碱基,获得含磷酸基团核苷酸空隙的DNA,再通过羟基引入荧光标记物,加入PFP后可得到PFPDNA复合物,通过荧光共振能量转移(fluorescence resonance energy transfer,FRET)进行氧化损伤DNA的检测。对方法的影响因素进行了考查和优化,包括PFP的浓度、DNA修复酶的种类、DNA聚合酶I的用量以及芬顿反应的时间等。研究表明,基于PFP荧光共振能量转移原理检测氧化损伤DNA方法具有灵敏度高和特异性强的优势,可确保检测的准确性,对老年疾病的预防医学具有很好的应用前景。     

榨前分离苹果清汁中香气成分分析

以榨前分离工艺制取的苹果清汁为试验样品,采用固相萃取技术结合GC-MS联用仪分析其香气物质的含量及组成,并与传统工艺清汁中香气的差异进行比较. 结果表明,榨前分离苹果清汁经气质分离出30个峰共鉴定了23种香气成分,总量为2223μg/mL,传统工艺果汁分离出50个峰共鉴定了34种香气成分,总量为5436μg/mL. 传统工艺苹果清汁与榨前分离清汁香气成分的种类和含量有显著性差异,尤其是含量多5911%,说明榨前分离工艺对苹果清汁的香气成分影响较大. 由于果皮是香气成分最集中和种类最丰富的部位,所以榨前分离工艺下果皮副产品中香气的回收与回添非常必要.