Targeted RNA interference of cyclin A(2) mediated by functionalized single-walled carbon nanotubes induces proliferation arrest and apoptosis in chronic myelogenous leukemia K562 cells

Cyclin A(2) plays critical role in DNA replication, transcription, and cell cycle regulation. Its overexpression has been detected and related to many types of cancers including leukemia, suggesting that suppression of cyclin A(2) would be an attractive strategy to prevent tumor progression. Herein, we apply functionalized single wall carbon nanotubes (f-SWNTs) to carry small interfering RNA (siRNA) into K562 cells and determine whether inhibition of cyclin A(2) would be a potential therapeutic target for chronic myelogenous leukemia.

Simultaneous electrochemical determination of uric acid, dopamine, and ascorbic acid at single-walled carbon nanohorn modified glassy carbon electrode

Single-walled carbon nanohorn modified glassy carbon electrode (SWCNH-modified GCE) was first employed for the simultaneous determination of uric acid (UA), dopamine (DA), and ascorbic acid (AA). The SWCNH-modified GCE displayed excellent electrochemical catalytic activities. The oxidation overpotentials of UA, DA, and AA decrease significantly and their oxidation peak currents increase dramatically at SWCNH-modified GCE. Linear sweep voltammetry (LSV) was used for the simultaneous determination of UA, DA, and AA in their ternary mixture. The peak separations between UA and DA, and DA and AA are large up to 152 mV and 221 mV, respectively.

有机半导体中载流子迁移率的测量方法

本文简要地介绍了有机半导体中载流子迁移率的几种模型,着重阐述了测量有机半导体中载流子迁移率的各种方法的测试原理。主要有如下几种:稳态(CW)直流电流-电压特性法(steady-state DC JV),飞行时间法(time of flight,TOF),瞬态电致发光法(transient electroluminescence,transient EL),瞬态电致发光法的修正方法即双脉冲方波法和线性增压载流子瞬态法(carrier extraction by linearly increasing voltage,CELIV),暗注入空间电荷限制电流(dark injection space charge limited current,DI SCLC),场效应晶体管方法(field-effect transistor,FET),时间分辨微波传导技术(time-resolved microwave conductivity technique,TRMC),电压调制毫米波谱(voltage-modulated millimeter-wave spectroscopy,VMS)光诱导瞬态斯塔克谱方法(photoi...

Hydrothermal synthesis and structure of [Ni(en)(2)V6O14](n)

A new complex [Ni (en)(2)V6O14](n) was hydrothermally synthesized and characterized by 2-dimensional vanadium oxide framework pillared by Ni(en)(2)group. Single crystal X-ray analysis indicates that this compound crystallizes in monoclinic system, space group P2(1)/c with a=0. 892 17(18) nm, b = 1. 711 1(3) nm, c=0. 662 73(13) nm, beta=111. 58(3)degrees, V=0.940 8(3) nm(3), Z=2, D-c=2.501 g/cm(3), R=0. 042 3, omegaR=0. 060 9, S=1. 006.

Encapsulation and luminescence of the nanostructured supramolecular material [Eu(Phen)(4)](NO3)(3)/(CH3)(3)Si-MCM-41

The nanostructured material (NSM) of pure silica MCM-41 molecular sieve was synthesized with tetraethyl orthosilicate (TEOS) as the source of silica and cetyltrimethylammonium bromide (CTMABr) as the template under supersonic wave condition. Then NSM of (CH3)(3)Si-MCM-41 was obtained by introducing trimethylsilyl to MCM-41. (CH3)(3)Si-MCM-41 showed the similar TEM and XRD photographs with the normal crystal of MCM-41 and the diameter of the NSM crystallites with a hexagon shape is of about 10-40 nm. The dispersivity of (CH3)(3)Si-MCM-41 prevails over the NSM of MCM-41 as its hydrophobicity. The fluorescent intensity of (CH3)(3)Si-MCM-41 is 3.4 times as that of the MCM-41. The luminescent functional supramolecular nanostructured material was prepared in EtOH, and characterized by TEM, HRTEM, XRD, TG, IR, and elemental analysis. The results showed that the [Eu(Phen)(4)](NO3)(3) had entered into the channels of nanosized mesoporous sieve of (CH3)(3)Si-MCM-41, forming discrete centers of luminescence. The energy transferring of the host to guest, superficial effect of NSM, quanta tunnel effect, and discrete luminescent center result in the fluorescent intensity of the supramolecule enhancement.

A chromic molybdenum phosphate with a tunnel structure: hydrothermal synthesis and structure of (NH3CH2CH2NH3)(2) center dot (NH3CH2CH2NH2)(3)center dot[NaCr2Mo12O30(PO4)(HPO4)(4)(H2PO4)(3)]center dot 6H(2)O

A chromic molybdenum phosphate, (NH3CH2CH2NH3)(2).(NH3CH2CH2NH2)(3).[NaCr2Mo12O30(PO4)(HPO4)(3)]. 6H(2)O, involving molybdenum present in V oxidation, has been hydrothermally synthesized and structurally characterized by single crystal X-ray diffraction and IR spectrum. Deep brown-red crystals are formed in the triclinic system, space group P (1) over bar, a = 12.067(2), b = 14.677(3), c = 21.290(2) Angstrom, alpha = 80.940(10)degrees, beta = 82.960(10)degrees, gamma = 76.61(2)degrees. The structure of the title compound may be considered to be two [Mo6O15(HPO4)(H2PO4)(3)](5-) units bonded to a chromic atom, although several P-O groups are not protonated on account of coordination with a Na+ cation. The one-dimensional tunnels were formed in the solid of the title compound. (C) 2000 Elsevier Science B.V. All rights reserved.

Prediction of C-13-nuclear magnetic resonance chemical shifts for aliphatic amines

Prediction of C-13-nuclear magnetic resonance chemical shifts for aliphatic amines is performed. The topological, geological and electronic descriptors are generated. To reduce the variables, the best subsets of the descriptors are obtained by using leaps-and-bounds regression analysis. The model is achieved using multiple regression with satisfactory results.

脂肪胺类化合物的~(13)C核磁共振波谱模拟

对脂肪胺类化合物的1 3C核磁共振波谱进行了模拟 ,所用方法为数学模型法。为此 ,提取了共振碳原子所处化学环境的拓扑特征、几何特征及电子特征。运用变量最优子集回归法对变量进行了选择 ,用多元回归法构造了数学模型 ,得到了比较满意的预测结果。

Photoluminesence and electroluminescence of the blue emission of devices based on poly(p-phenylenevinylene) copolymers

Bright blue polymer light-emitting diodes have been fabricated by using the poly(p-phenylenevinylene)-based copolymers with 10 C long aliphatic chains as the electroluminescent layers, PBD in PMMA and Alq(3) as the electron-transporting layers, and aluminum as the cathode. The multilayer structure devices show 190 cd/m(2) light-emitting brightness at 460 nm, 15 V turn-on vol- tage. It is found that the intensities of photoluminescence and electroluminescence (EL) increase with increasing aliphatic chain length, the EL intensity and operation stability of these polymer light-emitting diodes can be improved by reasonable design of the structure.

An estimate of divergence time of parazoa and eumetazoa and that of cephalochordata and vertebrata by aldolase and triose phosphate isomerase clocks

Previously we suggested that four proteins including aldolase and triose phosphate isomerase (TPI) evolved with approximately constant rates over long periods covering the whole animal phyla. The constant rates of aldolase and TPI evolution were reexamined based on three different models for estimating evolutionary distances, It was shown that the evolutionary rates remain essentially unchanged in comparisons not only between different classes of vertebrates but also between vertebrates and arthropods and even between animals and plants, irrespective of the models used, Thus these enzymes might be useful molecular clocks for inferring divergence times of animal phyla, To know the divergence time of Parazoa and Eumetazoa and that of Cephalochordata and Vertebrata, the aldolase cDNAs from Ephydatia fluviatilis, a freshwater sponge, and the TPI cDNAs from Ephydatia fluviatilis and Branchiostoma belcheri an amphioxus, have been cloned and sequenced, Comparisons of the deduced amino acid sequences of aldolase and TPI from the freshwater sponge with known sequences revealed that the Parazoa-Eumetazoa split occurred about 940 million years ago (Ma) as determined by the average of two proteins and three models, Similarly, the aldolase and TPI clocks suggest that vertebrates and amphioxus last shared a common ancestor around 700 Ma and they possibly diverged shortly after the divergence of deuterostomes and protostomes.

双刺纺锤水蚤（Acartia bifilosa）基础生物学与生态学研究

20世纪90年代以来，为了确保日益增长的人口对蛋白质的需求，海洋鱼类养殖在全球范围内日趋发展。然而，许多养殖鱼类的品质如抗病力、口味等与野生种类相比大为降低。饵料对于鱼类品质的好坏起着至关重要的作用。在海洋的自然环境中，浮游动物，特别是数量庞大、种类繁多的桡足类是野生鱼类的天然活饵料。哪些桡足类适于作养殖饵料，如何获得、从何处获得桡足类，人工培养是否可行，能否通过加入桡足类来改善养殖鱼类的品质是长期以来业内人士一直关注的问题，需要大量的基础性探索研究工作。 开展有潜在开发价值种的生物学特性及室内培养的基础研究，进而开展大量生产技术的研究与应用，不仅是开发利用桡足类的一个重要途径，而且可以获得一些重要的生态学参数。 本论文自2003年10月－2004年9月之间，在胶州湾采集不同的桡足类种类，通过室内比较培养实验，选定双刺纺锤水蚤作为具有开发潜力的研究培养对象，对其展开一系列培养条件及生物学特性研究，在此基础上进行了小水体增殖培养，结合现场调查资料对与其生活策略相关的生态学问题进行了初步研究探索。结果如下： 筛选：2003年10月－2004年9月全年不同季节共采集11 种桡足类，在室内自然温度、自然海水（盐度30－32）下长时间培养，粗略筛选出能够经受实验室人工养殖水体生活的种类有：强额拟哲水蚤（Paracalanus. crassirostris）、汤氏长足水蚤（Calanopia thompson）、太平洋真宽水蚤（Eurytemora pacifica）、双刺纺锤水蚤（Acartia bifilosa）。对上述种类的成体和子代幼体分别测定其对不同盐度、温度的耐受能力。培养结果表明：18℃室温下，强额拟哲水蚤幼体在盐度20以上的环境中，存活时间不超过11天；汤氏长足水蚤雌体在培养温度低于20℃时，只能存活10天；25℃室温下，当盐度低于20时，汤氏长足水蚤雌体存活时间不超过9天，子代的存活时间不超过7天；太平洋真宽水蚤不适宜在温度较高的夏秋季培养，幼体在不同盐度的实验条件下存活时间不超过5天，不适宜长期培养；双刺纺锤水蚤在全年8－24℃的室内培养温度范围内保持了24－85％的存活率，雌体和子代在盐度10－35的范围内都能存活，最终结果表明双刺纺锤水蚤是其中最适宜进行人工培养的种类。 繁殖：对双刺纺锤水蚤雌体的培养条件和繁殖生物学的研究结果表明：在本实验所使用的6种微藻饵料：微绿球藻（Nannochloropsis oculata）、小球藻（Chlorella.sp）、等鞭金藻（Isochrysis galbana）、三角褐指藻(Phaeodactylum tricornutum)、亚心型扁藻(Platymonas subordiformis)、中肋骨条藻(Skeletonema costatum)中，亚心型扁藻和中肋骨条藻适宜成体培养，亚心型扁藻对雌体存活有利，排粪率也要比中肋骨条藻低得多，亚心型扁藻在高温条件下的饵料利用效率要高于中肋骨条藻，中肋骨条藻对产卵有利，二者混合优势互补；预饥饿处理的双刺纺锤水蚤恢复到最高产卵率需要较长的时间，并且一直保持较低的产卵率；该种繁殖的最适温度范围15－20℃；在10－25℃温度范围内的平均产卵率差异并不显著。 生长及发育：对双刺纺锤水蚤幼体培养条件及发育生物学研究结果表明：在本实验所使用的6种微藻饵料中，微绿球藻是比较理想的开口饵料；粒径小（ 4 m）的微藻——微绿球藻和小球藻不能保证双刺纺锤水蚤后期无节幼体发育至桡足阶段，22℃以下采用微绿球藻 + 亚心型扁藻 + 中肋骨条藻的食物搭配，22℃以上需加入粒径在4m左右的等鞭金藻。 世代时间：通过一系列的温度梯度实验，证明在相同饵料的情况下，温度对双刺纺锤水蚤的发育具有显著的影响，在15－25℃的范围内，随着温度的升高，生长速度加快、世代周期缩短；在温度条件为15、18、20、22、25℃下的世代时间分别为25.5, 18.5, 13, 11.5, 9.5天。 群体培养：研究了适宜的微藻饵料种类搭配比例以及总饵料浓度对种群日均增值率的影响。结果表明：20℃下培养宜采用亚心型扁藻：中肋骨条藻：微绿球藻按含碳量2:1:1的比例组成混合饵料，达到最高增殖率的混合饵料浓度范围在1.0－4.0 μg C ml-1之间；25℃下培养宜采用亚心型扁藻：中肋骨条藻：微绿球藻：等鞭金藻按含碳量2:1:1:2的比例组成混合饵料，日均增殖率在混合饵料总浓度为1.0 μg C ml-1 时最高，低于和高于此浓度都会降低日增值率。 度夏机制：针对野外大面调查发现双刺纺锤水蚤在高温季节的胶州湾内仍然存在的事实（传统观点认为该种在夏季从水体中消失，通过休眠卵度夏），本论文从基础生态学研究出发，根据胶州湾夏季的温度和叶绿素浓度资料，设计实验研究了高温和饵料浓度对成体繁殖和幼体生长发育的影响。实验发现，饵料浓度对高温下雌体的繁殖有着明显的影响，15g Chla l-1浓度下的雌体在28℃都可以保持产卵状态，而且卵的孵化率也在50％以上；各处理中的卵都很快孵化，并保持了60％以上的孵化率；高浓度组15 g Chla l-1和10 g Chla l-1，无节幼体都能发育至成体，低浓度5 g Chla l-1处理组中，28℃下，不能发育至桡足阶段，而25℃下也只能发育至C4期。在本实验中没有发现双刺纺锤水蚤产生休眠卵。在胶州湾自然环境中发现该种全年存在。胶州湾中的双刺纺锤水蚤在夏季能够在不产生休眠卵的情况下安全度夏。

高寒湿地生态系统土壤有机物质补给及地-气CO_2交换特征

海北高寒湿地植物地上、地下生物现存量较高，2004年海北高寒湿地植物净初级生产力为1799．7gC•m~(-2)．由于家畜对湿地植物采食量低，每年将有大量的枯黄植物残留于地表，表现出地上、地下生物量以及苔鲜均成为土壤有机物质的补给源．由于区域温度低，积水严重，对植物残体分解缓慢，导致湿地土壤有机质含量很高，形成了厚达2m左右的泥炭层．观测结果表明，海北高寒湿地净生态系统CO_2交换量具有明显的季节变化，年内4月和10月存在两个CO_2释放高峰期，夏季的7～8月为一个强吸收期，全年来看为一个巨大的碳源．2004年净生态系统年碳交换量为76．7gC•m~(-2)．计算结果表明，植被的呼吸消耗量每年为1199．8gC•m~(-2)，其植物总固碳量为2999．5gC•m~(-2)，而土壤呼吸为1876．4gC•m~(-2)．

寒冻雏形土不同地形部位土壤湿度及其与主要植被类型的对应关系

寒冻雏形土不同地形部位土壤湿度均有较高的水平,0cm～60cm整层土壤湿度北坡> 滩地> 南坡。土壤湿度在年内可分为春季水分消耗期、雨季初水分补给期、水分波动消耗期和冬季冻结水分稳定聚集期。在垂直方向随深度加深湿度逐渐降低,北坡极为明显,南坡及滩地降低幅度均匀。土壤湿度随时间的变化过程分解为周期性变化项、随机性分量项及趋势项。同时表明,在土壤湿度较低的南坡,以小嵩草等为主的草原化草甸植被类型；土壤湿度适中的滩地,多以矮嵩草为主的高寒嵩草草甸植被类型；湿度较高的北坡,多以金露梅为主的灌丛草甸植被类型；而在土壤湿度很高、地表长久积水的河边,多以藏嵩草等为主的沼泽化草甸植被类型。

柴达木盆地西区新生代构造演化

The Qaidam Basin constitutes a major portion of the northeastern Tibetan Plateau, and an understanding of its tectonic development will help decipher how the Tibetan Plateau was formed. It is shown that Late Cretaceous–Paleocene deposits of the western Qaidam Basin can be well correlated with their counterparts of the southwestern Tarim Basin, implying that the two regions were originally connected or were in the same depositional basin during that period of time. The Qaidam Basin commenced subsiding due to crustal shortening in the Eocene, and it has subsequently evolved into an independent basin since the Miocene. The main depocenter was noticeably persistent in the middle of the western Qaidam Basin from Eocene to Miocene time, and then it shifted to the east. On the basis of spatial stratigraphic correlation and restoration of sedimentary processes, we surmise that there existed a proto–Qaidam Basin during the Paleogene, where the Suhai and Kumukol Basins represent its northern and southern margins, respectively. The Suhai and Kumukol Basins were subsequently isolated from the Qaidam Basin as a result of basinward thrusting in basin-margin areas. It is shown that the western Qaidam Basin experienced three distinct stages: the first stage was characterized by a simple synclinal depression; the second stage was marked by occurrence of reverse faults at inflection points of the megafold and continuous subsidence in the middle of the basin; and the third stage featured intrabasinal deformation and uplift. The eastern Qaidam Basin underwent a diverse evolution and became the main depositional area in the Quaternary. It is suggested that the Qaidam Basin should be generated as a result of crustal buckling or folding, manifesting itself as a synclinal depression. The crustal folding model can account for a number of observations, including localization of the depocenter in the middle of the basin, nearly concomitant deformation on the south and north sides of the Qaidam Basin, occurrence of major high-angle reverse faults at basin margins, and generation of adjacent intermontane Suhai and Kumukol Basins. A tectonic model is accordingly advanced to illustrate Cenozoic tectonics of the Qaidam Basin.