不同氮浓度对绿球藻生长及生理特性的影响

采用藻类生物测试标准方法研究了不同氮浓度条件下绿球藻(Chlorococcumsp.)的生长及生理变化.结果表明,相对BG11(1.500g/LN)培养基,低N条件下(0.015,0.150g/L)绿球藻生长较好,对N的吸收率高达85%以上;高N条件下(4.500~30.000g/L)被试藻类生长减缓甚至停滞,但对N的吸收率仍达70%~80%.当N浓度>4.500g/L时,绿球藻Chl-a+Chl-b的含量呈逐渐减少趋势;当N浓度>1.500g/L,绿球藻硝酸还原酶(NR)活性、丙二醛(MDA)含量、过氧

我国内陆水体单殖吸虫的宿主特异性分析

报道我国内陆水体单殖吸虫的宿主特异性的研究。研究表明单殖吸虫有很强的宿主特异性 ,但不同种类的特异性有很大的差别。从目前已有的记录来看 ,60 %以上的单殖吸虫只有 1种宿主 ,约 75%的单殖吸虫的宿主仅为 1属 ,超过97%的单殖吸虫的宿主在 1科之内。没有 1种单殖吸虫可寄生于超过 3个科的宿主中 ,但大钩指环虫可在 2 3属 33种宿主中寄生。在科和属特异性水平上 ,以锚首虫科和指环虫科单殖吸虫的特异性较强 ,三代虫科次之 ,双身虫科最弱 ;而在种特异性水平上 ,这四科单殖吸虫的宿主特异性并无显著

Label-free detection of human prostate-specific antigen (hPSA) using film bulk acoustic resonators (FBARs)

Label-free detection of cancer biomarkers using low cost biosensors has promising applications in clinical diagnostics. In this work, ZnO-based thin film bulk acoustic wave resonators (FBARs) with resonant frequency of ∼1.5 GHz and mass sensitivity of 0.015 mg/m2 (1.5 ng/cm2) have been fabricated for their deployment as biosensors. Mouse monoclonal antibody, anti-human prostate-specific antigen (Anti-hPSA) has been used to bind human prostate-specific antigen (hPSA), a model cancer used in this study. Ellipsometry was used to characterize and optimise the antibody adsorption and antigen binding on gold surface. It was found that the best amount of antibody at the gold surface for effective antigen binding is around 1 mg/m2, above or below which resulted in the reduced antigen binding due to either the limited binding sites (below 1 mg/m2) or increased steric effect (above 1 mg/m2). The FBAR data were in good agreement with the data obtained from ellipsometry. Antigen binding experiments using FBAR sensors demonstrated that FBARs have the capability to precisely detect antigen binding, thereby making FBARs an attractive low cost alternative to existing cancer diagnostic sensors. © 2013 Elsevier B.V.

铜、汞、镉、六六六和对硫磷对食蚊鱼生长的影响

对2日龄的食蚊鱼仔鱼的急性毒性,96小时LC_(50)是:铜,0.28毫克/升;汞,0.58亳克/升;镉,10.2毫克/升;六六六(丙体),0.53毫克/升;对硫磷,0.3毫克/升。依据20天的生长数据求得的铜、镉和对硫磷的最大允许毒物浓度分别是0.015—0.030、0.005—0.010和0.0015—0.0030毫克/升,相应的应用系数分别为0.05—0.1、0.0005—0.0009和0.005—0.01。

Determinations of MC-LR and [Dha(7)] MC-LR Concentrations and Physicochemical Properties by Liquid Chromatography-Tandem Mass Spectrometry

A liquid chromatography electrospray mass spectrometry (LC/ESI/MS) method working in multiple reactions monitoring mode for the determination of trace amounts of microcystin variants (MC-LR and [Dha(7)] MC-LR) in waters was developed. The limit of quantification was 0.05 mu g/L and the limit of detection was 0.015 mu g/L for MC-LR and [Dha(7)] MC-LR, respectively. Recoveries for MCs were in the range of 68%-81%. MC-LR and [Dha(7)] MC-LR were chemically stable with similar physiochemical behavior.

Origin of Gymnocypris przewalskii and phylogenetic history of Gymnocypris eckloni (Teleostei : Cyprinidae)

The origins and phylogenetic patterns were assessed for G. przewalskii and G. eckloni by analyzing the complete mtDNA cytochrome b gene sequence (1140bp). Phylogenetic analyses further supported that there were three mtDNA lineages (A-C) identified in G. przewalskii and G. eckloni, demonstrating that outer rakers of the first gill have little significance in the phylogeny of the Gymnocypris fishes. The network established showed that G. eckloni of the Yellow River specific haplotype A1 was a founder and it radiated all haplotypes of G. przewalskii which suggested G. przewalskii might only originate from one of two maternals of G. eckloni from the Yellow River. Fs test and mismatch analysis showed at least two expansion events in the population of G. przewalskii about 0.2734 Ma and 0.0658 Ma, while G. eckloni from Qaidam Basin could have experienced severe bottleneck effect about 0.0693 Ma. The population expansion was detected in subclades A1 and A21 with the most recent common ancestor (TMRCA) about 0.2308 +/- 0.01 Ma and 0.1319 +/- 0.015 Ma, respectively, which were within the geological age range of "Gonghe Movement" event that caused the separation of Lake Qinghai from the upper Yellow River. These results suggested the effect of the fish diversification by rapid uplift of the Qinghai-Tibetan Plateau in the Late Pleistocene.

The costs and benefits in an unusual symbiosis: experimental evidence that bitterling fish (Rhodeus sericeus) are parasites of unionid mussels in Europe

Interspecific symbiotic relationships involve a complex network of interactions, and understanding their outcome requires quantification of the costs and benefits to both partners. We experimentally investigated the costs and benefits in the relationship between European bitterling fish (Rhodeus sericeus) and freshwater mussels that are used by R. sericeus for oviposition. This relationship has hitherto been thought mutualistic, on the premise that R. sericeus use mussels as foster parents of their embryos while mussels use R. sericeus as hosts for their larvae. We demonstrate that R. sericeus is a parasite of European mussels, because it (i) avoids the cost of infection by mussel larvae and (ii) imposes a direct cost on mussels. Our experiments also indicate a potential coevolutionary arms race between bitterling fishes and their mussel hosts; the outcome of this relationship may differ between Asia, the centre of distribution of bitterling fishes, and Europe where they have recently invaded.

Surface roughness and high density of cubic twins and hexagonal inclusions in cubic GaN epilayers

Surface roughness and its correlation with the polarity of internal hexagonal inclusions and cubic twins have been investigated by atomic force microscopy (AFM), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray diffraction (XRD). The surface roughness resulted from large amount of strips, which prolonged in [1 (1) over bar0] direction with small size in [110] or [110] direction. The sidestep of each strip is just the top of high density of hexagonal inclusions or cubic microtwins. Moreover, XRD shows that the amount of hexagonal inclusions and cubic microtwins measured in [110] direction are twice or more as much as in [110] direction. Therefore, it is hexagonal inclusions, cubic twins and their distributive polarity that is responsible to the surface characteristics of cubic GaN epilayers.

AlGaInP visible quantum well lasers for information technology

650 nm-range AlGaInP multi-quantum well (MQW) laser diodes grown by low pressure metal organic chemical vapor deposition (LP-MOCVD) have been studied and the results are presented in this paper. Threshold current density of broad area contact laser diodes can be as low as 350 A/cm(2). Laser diodes with buried-ridge strip waveguide structures were made, threshold currents and differential efficiencies are (22-40) mA and (0.2-0.7) mW/mA, respectively. Typical output power for the laser diodes is 5 mW, maximum output power of 15 mW has been obtained. Their operation temperature can be up to 90 degrees C under power of 5 mW. After operating under 90 degrees C and 5 mW for 72 hrs, the average increments for the threshold currents of the lasers at 25 degrees C and the operation currents at 5 mW (at 25 degrees C) are (2-3) mA and (3-5) mA, respectively. Reliability tests showed that no obvious degradation was observed after 1400 hours of CW operation under 50 degrees C and 2.5 mW.

稀土氟化物固体电解质的制备、结构及电学、传感性能的研究

我们利用湿法制备了单一稀土氟化物LnF_3(Ln = La 、Ce、Nd、Gd、Tb、Dy、Er、Yb、Y), 并采用高温固相反应制备了稀土掺杂氟化物Ln_(1-x)MxF_(3-δ)(Ln = La、Ce、Gd、Yb、Y M = Ca、Sr、Ba)。用X射张衍射方法研究了它们的晶体结构。对单一稀土氟化物，LaF_3、CeF_3、NdF_3为六方晶系，GdF_3、TbF_3、DyF_3、DrF_3、YbF_3、YF_3为正交晶系。对掺杂氟化物，La_(0.95)Ba_(0.05)F_(3-δ)、Ce_(0.95)Ca_(0.05)F_(3-δ)、Yb_(0.70)Sr_(0.30)F_(3-δ)为固溶体，Ce_(0.95)Ca_(0.05)F_(3-δ)的晶胞参数比CeF_3的略为变小；Gd_(0.85)Ca_(0.15)F_(3-δ)、Y_(0.71)Ca_(0.29)F_(3-δ)为新化合物，Gd_(0.85)Ca_(0.15)F_(3-δ)的晶体结构由GdF_3的正交晶系变为六方晶系，其晶胞参数为：a=3.973A, C=7.124A, γ=120°, Y_(0.71)Ca_(0.29)F_(3-δ)化合物的晶体结构与YF_3相同为正交晶系，晶胞参数却较小：a=3.683A、b=6.978A, c=3.396A。 我们对氟化物的烧结陶瓷片进行了直流电导率测量。对单一稀土氟化物，结果表明六方结构的化合物的电导率高于正交结构的，对于相同结构的氟化物，一般地，稀土离子半径越大，电导率越高；对于掺杂氟化物，由于二价碱土金属离子掺杂可以提高氟离子空位浓度，因此掺杂物的电异率均高于对应的单一稀土氟化物，其中Gd_(0.85)Ca_(0.15)F_(3-δ)掺杂后变成更利于离子导电的六方结构。采用压片工艺，以La_(0.95)Ba_(0.05)F_(3-δ)、Ce_(0.95)Ca_(0.05)F_(3-δ)、Gd_(0.85)Ca_(0.15)F_(3-δ)和Y_(0.71)Ca_(0.29)F_(3-δ)为固体电解质材料制备电位输出式氧传感器件，并利用调节N_2、O_2流量比控制氧分压的方法，对器件的敏感性能进行测试。结果表明该类器件可在150 ℃的低温下对氧气敏感，器件的输出电位差与氧分压的对数值有较好的线性关系。器件的响应时间在2分与9分之间。该类器件的敏感机理是：氧气先吸附敏感电极上，发生还原反应后生成的氧负离子在敏感电极与固体电解质界面上发生晶格置换反应，使得氧分压的改变通过快离子即氟离子在两个界面上（另一界面为参比电极与固体电解质界面）的电化学势差的变化与输出电位差值的改变联系起来，从而实现利用输出电位差测定氧分压的目的。根据使用的敏感电极材料，可以有单电子反应和双电子反应两种敏感机理。器件是由参比电极、固体电解质、敏感电极三个部分构成。我们采用固定其中二个部分的材料，改变第三个部分的用料的方法，对器件的敏感性进行了对比研究：A、我们首先固定固体电解质为Ce_(0.95)Ca_(0.05)F_(3-δ)、敏感电极材料为Pt黑，采用不同的参比电极材料Bi+BiF_3、Sb+SbF_3、Mg+MgF_2、Zn+ZnF_2制备了器件。性能测试结果表明使用Bi+BiF_3参比电极材料的器件稳定性和敏感性都比其它器件好。器件的输出电位差取决于参比电极氟化物的标准生成自由能的大小。B、固定Bi+BiF_3为参比电极材料，Ce_(0.95)Ca_(0.05)F_(3-δ)为固体电解质，使用不同的敏感电极材料Pt黑、Pd粉、Ag粉和RuO_2制备器件。性能测试结果表明：Pt材料器件的精确度较高，Pd材料器件的响应最快（2分），RuO_2材料器件的敏感性较好。使用Ag、RuO_2敏感电极材料的器件采用的是单电子反应敏感机理：O_2 + e <-> O_2~-, O_2~- + V_F + F_(F-bar)~- <-> O_(F-bar) + O_F + F_(F-bar)。而使用Pt、Pd敏感电极材料的器件采用双电子反应敏感机理：O_2 + 2e <-> 2O~-, 2O~- + F_(F-bar) <->O_(F-bar) + F~-。C、我们固定Bi+BiF_3为参比电极材料，Pt和RuO_2为敏感电极材料，使用La_(0.95)Ba_(0.05)F_(3-δ)、Ce_(0.95)Ca_(0.05)F_(3-δ)、Gd_(0.85)(Ca_(0.015)F_(3-δ)、Yb_(0.70)Ca_(0.29)F_(3-δ)制备了两个系列的器件。结果表明，无论是使用Pt还是使用RuO_2为敏感电极材料，都有下列的结论：用Ce_(0.95)Ca_(0.05)F_(3-δ)的器件的精确度较高，La_(0.95)Ba_(0.05)F_(3-δ)材料器件的敏感性最好，而Gd_(0.85)(Ca_(0.015)F_(3-δ的响应最快（Pt器件2分，RuO_2器件5分）。并未发现同时具备各种较好性能的器件，与敏感电极材料对器件性能的影响相比，固体电解质材料的影响要小。对于材料完全相同的器件，我们还对工艺条件影响作了初步研究。制备器件的工艺条件由于各种难以控制的因素不会每次、每批完全相同，工艺条件的差别也会影响器件的各方面性能。研究结果表明，工艺差别对器件的输出电位差值和响应时间的影响较大，对敏感性能的影响则较小。

取代环戊二烯基稀土有机氯化物的合成及其反应

本文通过无水LnCl_3(Ln = Pr.Nd.Gd)与两倍摩尔的叔丁基环戊二烯基碱金属盐在THF中60－80℃反应，分离到一类新的二（叔丁基环戊二烯基）稀土氯化物（T-DuCp）_2 2net.nTHF (Ln = Pr,Nd,n = 2 Ln = Gd,n = 1)，对它们进行了元素分析。红外光谱及水鲜色质谱的表征。对于配合物（t-BuCp）_2PrCl·2THF的单晶，测定了它的晶体结构，晶体层单斜晶系P21/C空间群，晶胞参数为：a = 15.080 b = 8.855 c = 21.196A, β = 110.34°V = 2653.9A~3 δ = 4，结构分析表明此配合物是一中性的单分子配合物。最后的R = Rw = 0.058平均Pr-C.2.81 Pr-Cent 2.53A, Pr-Cl及Rr-O键长分别为2.72与2.62A。本文通过Lnel_3(Ln = Nd.Pr.Ga)与等摩尔的叔丁基环戊二烯基碱金属盐在THF中60－80℃反应，分离到一类中性的单(叔丁基环戊二烯基)稀土二氯化物，并对它们进行了元素分析，红外光谱及水鲜色质谱的表征。本文通过轻稀土元素La,Pr的三氯化物与带基钠以1:2摩尔比在THF中70－80℃反应，分离到了二带基轻稀土氯化物（CaH_7）_2LaCl.2THF及[(CqH_7)_2PrCl.THF]_2。并且对此二配合物进行了元素分析。红外光谱及水鲜色质谱的表征。对于[(CuH_7)_2PrCl.TH]_2配合物，测定了它的晶体结构，这是第一个得到结构表征的茚基稀土氯化物，晶体层于单斜晶系，P_(21)/C空间群，晶胞参数为a = 7.808 b = 17.796 c = 14.070A β = 93.97°v = 1950.31A. E = 2最后的R = 0.045. Rw = 0.039结构分析表明此配合物以中性的二聚体形式存在。平均的Pr-C.2.81 Pr-Cent 2.53. Pr-Cl.2.84H Pr-O钻长2.54A。为了进一步研究不同配体对配合物结构的影响，我们还研究了Gael_3与Nae_5Mes以1:1摩尔比在THF中的反应，分离到了两种配合物[(NaTHF)(C_5MesGd.THF)_2Cl_5]_2.6THF(I)及L_5Me_5GdCl2.3THF(II)并且对配合物（I），测定了它的晶体结构，晶体层于三斜晶系。Pi空间群。晶胞参数a = 12.183 b = 13.638 c = 17.883A, α = 110.38 β = 94.04 γ = 99.44°, V = 2721.20A, E = 1。结构分析表明，此配合物是一种以两个Na原子通过THF中的O原子而桥联的金层有机配合物，在结构上有十分新颖的特点。在此配合物分子中含有四个Gd原子及二个Na原子，Na及Gd间以Cl桥键相联结，Gd-Gd_2 = 4.033 Gdll-Na = 2.818A。最后的R = 0.04M Rw = 0.042。本文还对（t-BuCp）_2P_2Cl.2THF与NaH及LiAlH4的反应进行了初步的研究，分离到（t-Bucp）_2PrH.2THF及(t-Bucp)_2P_2RIH_4.3THF两种新的氢化物，并且对它们进行了元素分析，红外光谱的表征，对于它们水鲜产物的气相分中的H_2，用气相色谱法进行了定性表征。

基于Vif-APOBEC3G相互作用的抗HIV-1药物研究

载脂蛋白B mRNA编辑酶催化多肽样蛋白3G(apolipoprotein B mRNA-editing enzyme catalyticpolypeptidelike3G,APOBEC3G或A3G)是人体天然抗病毒分子,可以使病毒逆转录形成的cDNA的胞嘧啶(C)脱氨为尿嘧啶(U),产生鸟嘌呤(G)→腺嘌呤(A)超突变,导致病毒转录产物突变,从而达到抑制病毒复制的作用。HIV-1的辅助蛋白Vif,可与APOBEC3G相互作用并导致其被降解,使得这一天然抗病毒机制失效,进而增强了HIV的感染力。Vif与APOBEC3G这种相互作用为抗HIV药物提供了新靶点。针对Vif-APOBEC3G相互作用的抗HIV抑制剂已经成为研究热点。本文综述了Vif和APOBEC3G的结构、二者的相互作用,以及基于这一相互作用的抗HIV-1抑制剂研究进展。