Molecular cloning and characterization of carp (Cyprinus carpio L.) CD8 beta and CD4-like genes

Partial cDNA sequences of both CD8 beta and CD4-like (CD4L) genes of common carp (Cyprinus carpio L.) were isolated from thymus cDNA library by the method of suppression subtractive hybridization (SSH). Subsequently the full length cDNAs of carp CD8 and CD4L were obtained by means of 3' RACE and 5' RACE, respectively. The full length cDNA of carp CD8 is 1164 bp and encodes 207 amino acids including a signal peptide region of 24 amino acids, a transmembrane region of 23 amino acids from aa 167 to aa189 and an immunoglobulin V-set from aa 19 to aa 141. Similar to other species CD8 beta s,carp CD8 beta also lacks p56(lck) domain in the cytoplasmic region. The full length cDNA of carp CD4L is 2001 bp and encodes 458 amino acids including four immunoglobulin (Ig)-like domains in the extracellular region, a transmembrane region of 23 amino acids at the C-terminal region from aa 402 to aa 424 and a cytoplasmic tail. Similar to mammalian, avian CD4s and fugu CD4L, carp CD4L also has the conserved p56(lck) tyrosine kinase motif (C-X-C) in the cytoplasmic region. RT-PCR analysis demonstrated that carp CD8 beta and CD4L genes were both expressed predominantly in thymus. The results from this study can be used to understand the evolution of both the CD8 beta and CD4 molecules which can be used as markers for cytotoxic and helper T cells in carp. (c) 2007 Published by Elsevier Ltd.

Weighted least squares with expectation-maximization algorithm for burst detection in U.K. water distribution systems

Flow measurement data at the district meter area (DMA) level has the potential for burst detection in the water distribution systems. This work investigates using a polynomial function fitted to the historic flow measurements based on a weighted least-squares method for automatic burst detection in the U.K. water distribution networks. This approach, when used in conjunction with an expectationmaximization (EM) algorithm, can automatically select useful data from the historic flow measurements, which may contain normal and abnormal operating conditions in the distribution network, e.g., water burst. Thus, the model can estimate the normal water flow (nonburst condition), and hence the burst size on the water distribution system can be calculated from the difference between the measured flow and the estimated flow. The distinguishing feature of this method is that the burst detection is fully unsupervised, and the burst events that have occurred in the historic data do not affect the procedure and bias the burst detection algorithm. Experimental validation of the method has been carried out using a series of flushing events that simulate burst conditions to confirm that the simulated burst sizes are capable of being estimated correctly. This method was also applied to eight DMAs with known real burst events, and the results of burst detections are shown to relate to the water company's records of pipeline reparation work. © 2014 American Society of Civil Engineers.

Changes in biomechanical properties of the coronary artery wall contribute to maintained contractile responses to endothelin-1 in atherosclerosis.

AIMS: Our aim was to determine whether alterations in biomechanical properties of human diseased compared to normal coronary artery contribute to changes in artery responsiveness to endothelin-1 in atherosclerosis. MAIN METHODS: Concentration-response curves were constructed to endothelin-1 in normal and diseased coronary artery. The passive mechanical properties of arteries were determined using tensile ring tests from which finite element models of passive mechanical properties of both groups were created. Finite element modelling of artery endothelin-1 responses was then performed. KEY FINDINGS: Maximum responses to endothelin-1 were significantly attenuated in diseased (27±3 mN, n=55) compared to normal (38±2 mN, n=68) artery, although this remained over 70% of control. There was no difference in potency (pD2 control=8.03±0.06; pD2 diseased=7.98±0.06). Finite element modelling of tensile ring tests resulted in hyperelastic shear modulus μ=2004±410 Pa and hardening exponent α=22.8±2.2 for normal wall and μ=2464±1075 Pa and α=38.3±6.7 for plaque tissue and distensibility of diseased vessels was decreased. Finite element modelling of active properties of both groups resulted in higher muscle contractile strain (represented by thermal reactivity) of the atherosclerotic artery model than the normal artery model. The models suggest that a change in muscle response to endothelin-1 occurs in atherosclerotic artery to increase its distensibility towards that seen in normal artery. SIGNIFICANCE: Our data suggest that an adaptation occurs in medial smooth muscle of atherosclerotic coronary artery to maintain distensibility of the vessel wall in the presence of endothelin-1. This may contribute to the vasospastic effect of locally increased endothelin-1 production that is reported in this condition.

Range-wide Yangtze freshwater dolphin expedition: The last chance to see Baiji?

Background, Aim and Scope. There are two species of fresh water cetaceans surviving in the Yangtze River system in China: Baiji (Lipotes vexillifer) and Yangtze finless porpoise (Neophocaena phocaenoides asiaeorientalis). As a result of the expansion of human activities on the river, their distribution ranges appear to be decreasing and in the case of the Baiji, are even being restricted to several sections. The Baiji is the world's most critically endangered cetacean species with a population estimated at only a few tens of individuals. The Yangtze finless porpoise is the world's only freshwater-adapted population of the species, and it has been estimated that only around 1,000 individuals remain in the river system. In order to prevent the extinction of Baiji and a sharp decline in the abundance of the porpoise, in situ conservation (i.e. in the river) and two ex situ conservation (i.e. in semi-natural reserves and in captivity) strategies were proposed and have been implemented since the early 1990s. In view of both the severely endangered status of the animals and the severely degraded conditions of their habitats, the feasibility and actual status of these two strategies are raised for discussion. Main Features. The threats faced by the cetaceans are mainly from the unfettered exploitation of the river's resources. In the past 20 years, five nature reserves have been established along the river. Imposing maximum prohibition of harmful and illegal fishing methods in the reserves might prolong the process of extinction of these cetaceans in the wild, but so far, the administrative measures taken in the reserves have not yet kept the abundance from sharply declining. As human use of the river and its resources is expected to intensify for many decades into the future, the ability of the river to continue to support these species is certainly undecided. Therefore, rescuing animals from the river and establishing viable breeding populations in semi-natural reserves, in which the environment is similar to the main stream of the river, and in captivity, has to be considered urgently as the short-term goal of ex situ strategies. Since the abundance of porpoises is higher than that of the Baiji, we have first established breeding populations of them in the semi-natural reserves and in captivity. But, considering the extremely low density of Baiji in the river, an immediate range-wide Yangtze Baiji survey is an urgent need for locating and capturing sufficient Baiji for successfully establishing a breeding population of them in semi-natural reserves. Results. Two semi-natural reserves (in Shishou, Hubei Province, and Tongling, Anhui Province) have been set up along the river in order to establish breeding populations of the Baiji and the porpoises. So far, several small groups of porpoises that were caught in the main stream of the river have successively been introduced into the semi-natural reserves. Under careful management, these animals in both of the semi-natural reserves not only survive, but can also reproduce naturally and successfully. At least one or three calves were born in each reserve each year. Additionally, a breeding group of porpoises is being established at the Baiji Dolphinarium at the Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan. There are presently four adults and one calf living in the Dolphinarium. The calf, born in July, 2005, is the first captive bred Yangtze Finless Porpoise in the world. In preparation for the range-wide Yangtze cetacean survey, a 9-day pilot expedition on the river near Wuhan was conducted in March, 2006, in order to develop methods for locating the Baiji. No Baiji were expected to be seen in such a short period but about 40 porpoise sightings were observed. Results of the pilot survey indicated that traditional visual and acoustical survey methods for cetaceans should be adapted to find the elusive Baiji in the river. Currently, the range-wide Yangtze cetacean survey is in preparation. The survey will cover over 1,700 km of the Yangtze River from Yichang to Shanghai, and is expected to provide detailed information on Baiji and porpoise numbers and distribution patterns in the river. Discussion. Although the short-term goal of ex situ conservation is to rescue cetaceans from the river and to establish viable breeding populations in semi-natural reserves and in captivity, the long-term goal of releasing the animals back into the river when the threats have decreased and the natural environment has been improved, should not be neglected. Moreover, the in situ conservation efforts in the natural reserves, and even in the entire Yangtze River system, including the lakes, should not be ignored or abandoned at any time. The activities contributing to the conservation of the Baiji and the porpoise in the wild have the incidental effect of benefiting the entire Yangtze ecosystem and other rare threatened species. The dynamics of the groups of porpoises in semi-natural reserves should be monitored continually, in order to guide the establishment of breeding groups of Baiji in these semi-natural reserves in the near future. Conclusions. Under the existing severely degraded conditions of the Yangtze system, the sharply fall populations of Baiji and porpoises will not be suspended in the foreseeable future. Therefore, ex situ conservation should be emphasized, and the severely threatened Baiji in the river should be removed and translocated to semi-natural reserves for establishing viable breeding populations. The successful program of capturing, translocating and maintaining finless porpoises in the Shishou semi-natural reserve has demonstrated its adequacy as an ex situ environment for cetaceans. Following the successful pilot survey in the river, the immediate range-wide Yangtze cetacean survey is proposed and is in preparation. The range-wide survey is expected to ensure that any remaining Baiji can be found reliably and captured successfully after the survey. Recommendations and Perspectives. During the range-wide survey, not only the Baiji but also the porpoise as well as their habitats should be investigated based on visual and acoustical methods that adapted to the river and the animals. Meanwhile, the current risk levels to the Baiji and porpoises should be evaluated at each area where Baiji or porpoises can be reliably sighted. Any capture efforts should be targeted on the most threatened areas, or where there is maximum risk of injury or death. The immediate track of the Baiji should be carried out once a Baiji is sighted during the range-wide survey in order to obtain the movement route of the animals, which is crucial information for the successful capture operation. Additionally, the need to establish new semi-natural reserves for the porpoises should be placed on the agenda of local and central governments in the near future.

Phylogeny of the East Asian botiine loaches (Cypriniformes, Botiidae) inferred from mitochondrial cytochrome b gene sequences

The Botiinae have traditionally represented a subfamily of the Cobitidae. At present, the classification and phylogenetic relationships of the Botiinae are controversial. To address systematic and phylogenetic questions concerning this group, we sequenced the complete cytochrome b gene from 34 samples, of which 24 represented 13 species of the East Asian botiine fishes, while the other 10 were non-botiine loach species. For the 1140 bp sequences determined, 494 sites were variable ones, of which 424 were parsimony informative. With Myxocyprinus asiaticus as an outgroup, molecular phylogenetic trees were constructed using the neighbor-joining, maximum parsimony, maximum likelihood and Bayesian methods. All molecular phylogenetic trees revealed that botiine fishes form a monophyletic group and are distantly related to other loaches, suggesting that the Botiinae should be placed in their own family. Within the Botiinae, there are three genera; Botia, Parabotia, and Leptobotia, each genus forming a monophyletic group, with the genus Botia as the most ancestral split. Our molecular results are in agreement with morphological analyses of botiines, suggesting that Botia is the ancestral genus, while Leptobotia and Parabotia were resolved as more derived sister groups.

Temperature- and salinity-dependent development of a Nordic strain of Ichthyophthirius multifiliis from rainbow trout

During the twentieth century evidence was presented which suggested the presence of various strains and races of the parasite Ichthyophthirius multifiliis Fouquet. However, ecological profiles of various parasite isolates from different climatic zones are sparse. Such stringent characterizations of parasite development at defined abiotic conditions could provide valuable criteria for the different races: profile comparison from various localities is one way to differentiate these strains. Baseline investigations were therefore performed on the associations between abiotic factors (temperature/salinity) and the development of theronts in tomocysts of I. multifiliis isolated from rainbow trout in a Danish trout farm. It was shown that tomocyst formation and theront development took place between 5 and 30degreesC. Development rates and sizes of theronts were clearly affected by temperature: theronts escaped tomocysts already after 16-27 h at 25degreesC and 30degreesC, whereas this process took 8-9 days at 5degreesC. Likewise, theront size decreased steadily from a maximum of 57.4 x 28.6 mum at 5degreesC to 28.6 x 20.0 mum at 30degreesC. This size variation was only partly associated with the number of theronts that appeared at different temperatures. The lowest number of theronts escaping from one tomocyst was indeed found at 5-7degreesC (mean 329-413). At 11.6, 17.0 and 21degreesC. the highest number of theronts appeared (mean 546-642). However, at 25 and 30degreesC, the number decreased (458 and 424, respectively). Additional studies on the salinity dependent development of the parasite (at 11.6degreesC) showed that salinities above 5 p.p.t. totally inhibited development. Even at 5 p.p.t. the developmental time significantly increased and the number of theronts produced from one tomocyst decreased.

Passively mode-locked YVO4/Nd : YVO4 composite crystal laser with a semiconductor saturable absorber as a high reflector

A passively mode-locked diode end-pumped YVO4/Nd:YVO4 composite crystal laser with a five-mirror folded cavity was first demonstrated in this paper by using a low temperature semiconductor saturable absorber mirror grown by metal organic chemical vapor deposition. Both the Q-switching and continuous-wave mode locking operation were realized experimentally. A stable averaged output power of 10.15 W with pulse width of about 11.2-ps at a repetition rate of 113 MHz was obtained, and the optical-to-optical efficiency of 43% was achieved.

Optical characteristics of InAs quantum dots capped with short period GaAs/InAs superlattices and InGaAs combination layers

Long wavelength light emission was realized by capping InAs quantum dots (QDs) with short period GaAs/InAs superlattices (SLs) and an InGaAs strain-reducing layer (SRL). The optical properties were systematically investigated by photoluminescence tests. With increasing the periods of SLs, the emission wavelength of InAs QDs shifts from 1.27 to 1.53 mum. We explain the redshift as a result of the increased QD height with the SLs and the reduced strain in the dot caused by InGaAs SRL. (C) 2004 Published by Elsevier Ltd.

不同前茬对设施黄瓜产量和品质及土壤酶活性的影响

试验研究了在延安日光温室不同前茬作物条件下,黄瓜随着生长季节的变化其产量和品质及土壤呼吸和酶活性的动态变化。结果表明,前茬为豇豆的黄瓜产量和土壤碱性磷酸酶活性较高,前茬为番茄的黄瓜可溶性糖含量和土壤呼吸强度较高,前茬为四季豆的黄瓜维生素C含量较高,前茬为翻青玉米的黄瓜硝酸盐含量和土壤脲酶活性较高,前茬为翻青黑豆的土壤蔗糖酶活性较高。从提高黄瓜产量的角度出发,豇豆-黄瓜是最佳模式,而从改善黄瓜品质的角度出发,番茄-黄瓜和四季豆-黄瓜是最优模式

钙钛矿型有机－无机杂化半导体材料的合成及其发光性质的研究

有机-无机钙钛矿型杂化半导体材料结合了有机和无机材料优点，并在分子水平上自组装形成复合材料，具有独特的光、电、磁等性质，在许多领域具有潜在的应用。基于第四主族金属卤化物的杂化钙钛矿是本论文研究的主题，这一类杂化钙钛矿材料是一类独特的半导体材料，其光功能引起人们越来越多的重视。 为此，本论文通过选择不同的有机阳离子配体制备了新型的基于卤化铅的有机－无机杂化钙钛矿结构单晶材料和薄膜，对它们的发光性质进行了研究。利用N-(3-胺基丙基)咪唑和溴化铅在氢溴酸溶液中反应得到了罕见的(110)取向杂化钙钛矿(C6H13N3)2PbBr4 (monoclinic, P21/c)。所得到的杂化钙钛矿在吸收(392 nm)及发射(424 nm)光谱中均存在激子的特征峰。同时，由于N-(3-胺基丙基)咪唑的光活性，得到的杂化材料具有独特的发光性质，在无机层与有机层之间发生了能量传递，使得有机配体的峰位发生红移并且发光强度明显增加。利用CASTEP (Cambridge Serial Total Energy Package) 总能计算软件包对配合物及配体的能带结构进行了计算。结果证明了配体在杂化材料中发光的红移及激子与配体间的能量传递。另外，还发现了一个有机配体2-(2-氨基乙基)硫脲也能够与金属卤化物络合形成(110)取向的有机－无机杂化钙钛矿结构C3H11SN3PbBr4(monoclinic P21/c)，由于有机配体的不同，2-(2-氨基乙基)硫脲构筑的(110)取向杂化钙钛矿结构较N-(3-胺基丙基)咪唑构筑的(110)取向杂化钙钛矿结构有较大程度的扭曲变形，使得它们的发光性质有所不同。 邻-(胺基甲基)吡啶，间-(胺基甲基)吡啶，对-(胺基甲基)吡啶在相同条件下与溴化铅组装，得到0-D [(m-C6H10N2)2PbBr6] (orthorhombic, Pbca), 1-D [(o-C6H10N2)PbBr4] (monoclinic, P21/c), 2-D [p-(C6H10N2)PbBr4] (orthorhombic, Pbca) 等不同维数的溴化铅骨架。其中间-(胺基甲基)吡啶与溴化铅在酸性条件下形成稀有的0-D杂化钙钛矿；邻-(胺基甲基)吡啶在相同条件下形成2-D层状杂化钙钛矿；对-(胺基甲基)吡啶则得到共边八面体组成的一维链。证实了有机配体氢键和空间位阻对无机结构的形成起限制作用。得到的杂化钙钛矿化合物的无机层激子特征吸收峰分别位于428 nm(0-D)和431 nm(1-D)，无机层激子特征发射峰位于461 nm (0-D)和467 nm(1-D)。 由于甲基咪盐的特殊胺盐构型，我们选用甲基咪盐取代的吡啶作为有机阳离子配体来构筑基于溴化铅的杂化钙钛矿，分别为3-甲咪基吡啶和4-甲咪基吡啶。3-甲咪基吡啶与溴化铅在酸性条件下构筑未见文献报道的即共点又共边的Pb-Br八面体连成无机层网络的杂化结构(C6H13N3)PbBr4 (monoclinic, C2/c)。4-甲咪基吡啶与溴化铅在相同条件下构筑的是常见的(100)取向的杂化钙钛矿结构(C6H13N3)PbBr4(orthorhombic, Pbca)。通过两个不同的化合物在结构和光学性质上的对比，表明有机阳离子配体对无机层结构以及杂化钙钛矿材料光学性质的影响。 在氢溴酸溶液中，组胺与卤化铅自组装成(100)取向杂化钙钛矿(C5H10N3)PbBr4 (monoclinic, P21/c)，(C5H10N3)PbCl4 (monoclinic, P21/c)。得到由扭曲的共角八面体组成的钙钛矿片层。受有机配体空间位阻及氢键的影响，无机层发生一定的扭曲，从而导致激子吸收较(分别位于419 nm，339 nm)线形脂肪胺有一定程度的红移。荧光光谱中存在基于溴化铅，氯化铅杂化钙钛矿激子的特征发射峰。另外作为比较，另一个复杂的有机胺3-氨基-1,2,4-三唑，在同样的条件下与PbBr2进行组装得到的是无机组分为一曲折的链状一维结构的杂化结构(C2H2N4)PbBr3 (orthorhombic, Pna21)。 线形的二咪唑配体2,2΄-(二咪唑基-甲基)苯和4,4΄-(二咪唑基-甲基)对联苯，由于其空间位阻与氢键的影响，与卤化铅的组装得到链状骨架。2,2΄-(二咪唑基-甲基)苯与氯化铅构筑的无机骨架是由共边铅氯三角锥连成的一维链状结构(C7H8N2)PbCl3 (triclinic, P-1)；与溴化铅形成类似交替排布的层状结构(C7H8N2)PbBr3 (triclinic, P-1)。4,4΄-(二咪唑基-甲基)对联苯构筑的氯化铅骨架为新奇的由共点的铅氯四方锥组成的类隧道形链(C20H21N4)Pb2Cl6•H2O (triclinic, P-1)；构筑的溴化铅骨架为由共边的铅溴八面体组成的双链(C20H21N4)Pb2Br6 (monoclinic, C2/c)。形成配合物的发光为配体本身的π-π*跃迁发光。 所合成的杂化钙钛矿材料都具有较好的成膜性，利用简单的旋涂法即可得到质量较好的薄膜材料，有利于对其进行光电研究。

可溶性甲壳素制取及其稀溶液性质的研究

从螃蟹壳中提取出甲壳素，并进一步进行脱乙酰基反应，制得了脱乙酰度（D.D）在49－100％范围的阳离子聚电解质可溶性甲壳素－壳聚糖。首次通过壳聚糖乙酸溶液的超声波降解快速制得了各个脱乙酰度系列，不同分子量的壳聚糖样品。将不同系列的各个样品在0.2M CH_3COOH + 0.1M CH_3COONa溶液中进行粘度和光散射（L.S）的研究，订定出了不同D.D壳聚糖的Mark-Houwink方程（30±0.05℃）如下：69％：[η]=0.1036*10~(-3) M_w~(1.12) (ml/g) 84%: [η]=1.424*10~(-3) M_w~(0.96) (ml/g) 91%: [η]=11.27*10~(-3)M_w~(0.84) (ml/g) 100%: [η]=16.80*10~(-3)M_w~(0.81) (ml/g)同时，对壳聚糖的其它某些稀溶液性质，如分子尺寸，第二维利系数，扩散因子等进行了求算，并对结果进行了讨论。将胶体滴定法应用到聚电解质壳聚糖的脱乙酰度（D.D）分析上，取得了满意的结果，建立了完整的测试方法，推导出了计算公式：D.D=(N_(PVSK)*ΔV*M_壳)/(5*C)*100%式中：N_(PVSK)-PVSK的当量浓度M_壳－完全脱乙酰基的壳聚糖链节分子量：161.15ΔV－消耗掉PVSK的体积差ΔV=V_1-V_2（升）C－壳聚糖溶液的浓度(g/ml)实验表明，不同D.D值的壳聚糖有着不同的折光指数增量dn/dc，由此创立了一个根据测dn/dc值求壳聚糖脱乙酰度的新方法。在0.2M CH_3COOH/0.1M CH_3COONa中，436nm，25±0.05℃时的计算公式如下：y=9.397*0.943式中：x-dn/dc (ml/g) y-D.D (%)。

Energy relaxation processes of hot quasi-two-dimensional excitons in very thin GaAs/AlGaAs quantum wells by exciton-acoustic-phonon interaction

The rising time of the excitonic luminescence in GaAs/AlGaAs quantum wells is studied as a function of the well width. For well thickness below approximately 20 Angstrom, we find an increase of rising time with decreasing well width. We explain the dependence of the rising time on well width in very thin quantum wells by the slow-down energy relaxation and/or exciton migration processes due to the decrease of the scattering rate of the exciton-acoustic-phonon interaction. (C) 1996 American Institute of Physics.