974 resultados para 114-1


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Hollow atoms in which the K shell is empty while the outer shells are populated allow studying a variety of important and unusual properties of atoms. The diagram x-ray emission lines of such atoms, the K-h alpha(1,2) hypersatellites (HSs), were measured for the 3d transition metals, Z=23-30, with a high energy resolution using photoexcitation by monochromatized synchrotron radiation. Good agreement with ab initio relativistic multiconfigurational Dirac-Fock calculations was found. The measured HS intensity variation with the excitation energy yields accurate values for the excitation thresholds, excludes contributions from shake-up processes, and indicates domination near threshold of a nonshake process. The Z variation of the HS shifts from the diagram line K alpha(1,2), the K-h alpha(1)-K-h alpha(2) splitting, and the K-h alpha(1)/K-h alpha(2) intensity ratio, derived from the measurements, are also discussed with a particular emphasis on the QED corrections and Breit interaction.

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The use of fac-[Mo(CO)(3)(MeCN)(eta(2)-L(1))] (1a) {L(1) = Ph(2)PN(Pr-i)PPh(DMP)}(2) as a precursor to metalloligands and bimetallic, heterotrimetallic, and heptacoordinated complexes is reported. The reaction of 1a with diphosphazane, dppa, or a diphosphinoalkane such as dppm or dppe yields the fac-eta(1)-diphosphine substituted metalloligands, fac-[Mo(CO)(3)(eta(2)-L(1))(eta(1)-PXP)] {PXP = dppa (2), dppm (3), and dppe (4)}. These undergo isomerization to yield the corresponding mer-diphosphine complexes (5-7). Oxidation of the uncoordinated phosphorus atom of the mer-eta(1)-dppm-substituted complex eventually provides mer-[Mo(CO)(3)-(eta(2)-L(1)){eta(1)-Ph(2)PCH(2)P(O)Ph(2)}](8). The structure of the latter complex has been confirmed by single crystal X-ray diffraction {triclinic system, P ($) over bar 1; a = 11.994(3), b = 14.807(2), c = 15.855(3) Angstrom; alpha = 114.24(1), beta = 91.35(2), and gamma = 98.95(1)degrees; Z = 2, 4014 data (F-0 > 5 sigma(F-0)), R = 0.066, R(W) = 0.069}. Treatment of the dppe metalloligand 7 with [PtCl2(COD)] yields the heterotrimetallic complex cis-[PtCl2{mer-[Mo(CO)(3)(eta(2)-L(1))(eta(1)-dppe]}(2)] (9). Attempts to prepare a related trimetallic complex with the dppm-containing metalloligand were unsuccessful; only the tetracarbonyl complex cis-[Mo(CO)(4)(eta(2)-L(1))] (1b) and cis-[PtCl2(eta(2)-dppm)] were obtained. Reaction of la with dppe in the ratio 2:1 yields the mer-mer dinuclear complex [{mer-[Mo(CO)(3)(eta(2)-L(1))]}(2)(mu-dppe)] (10) bridged by dppe. Oxidation of 1a with iodine yields the Mo(II) heptacoordinated complex [MoI2(CO)(2)(eta(3)-L(1))] (11) with tridentate PPN coordination. The same Mo(II) complex 11 is also obtained by the direct oxidation of the tetracarbonyl complex cis-[Mo(CO)(4)(eta(2)-L(1))] (1b) with iodine. The structure of 11 has been confirmed by X-ray diffraction studies {monoclinic system, Cc; a = 10.471(2), b = 19.305(3), c = 17.325(3) Angstrom; beta = 95.47(2)degrees; Z = 4, 3153 data (F-0 > 5 sigma(F-0)), R = 0.049, R(W) = 0.051}. This complex exhibits an unusual capped-trigonal prismatic geometry around the metal. A similar heptacoordinated complex 12 with a chiral diphosphazane ligand {L(3) = (S,R)-P(h)2PN-(*CHMePh)*PPh(DMP)} has also been synthesized.

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Asymmetrically dibridged dicopper(II) complexes, [Cu-2(OH)(O2CC6H4-p-Me)(tmen)(2)(H2O)](ClO4)(2) (1) and [Cu-2(OH)(O2CC6H4-p-OMe)(tmen)(2)(H2O)](ClO4)(2) (2) (tmen = N,N,N',N'-tetramethylethane-1,2-diamine), were prepared and structurally characterized. Complex 1 crystallizes in the monoclinic space group P2(1)/a with a = 17.718(2), b = 9.869(1), c = 19.677(2) Angstrom, beta = 115.16(1)degrees, V = 3114.3(6) Angstrom(3) and Z = 4. The structure was refined to R(wR(2)) = 0.067(0.178). Complex 2 crystallizes in the monoclinic space group P2(1)/a with a = 17.695(3), b = 9.574(4), c = 20.104(2) Angstrom, beta = 114.18(1)degrees, V = 3107(1) Angstrom(3) and Z = 4. The final residuals are R(wR(2)) = 0.067(0.182). The complexes have a [Cu-2(mu-OH)(mu-OH)(mu-O2CAr)](2+) core with tmen Ligands occupying the terminal sites of the core. In addition, one copper is axially bound to a water molecule. The Cu ... Cu distances and the Cu-OH Cu angles in the core are 3.394(1) Angstrom, 124.4(2)degrees for 1 and 3.374(1) Angstrom, 123.3(3)degrees for 2. The complexes show axial X-band EPR spectral features in methanol glass at 77 K giving g(perpendicular to) = 2.02, g(parallel to) = 2.3 (A(parallel to) = 165 x 10(-4) cm(-1)) and a visible band near similar to 630 nm in methanol. The complexes are weakly antiferromagnetic. A theoretical fit of the magnetic susceptibility data in the temperature range 40-295 K gives -J = 10 cm(-1), g = 2.05 for 1 and -J = 10 cm(-1), g = 2.0 for 2. Plots of -2J versus the Cu-OH-Cu angle (phi) in this class of asymmetrically dibridged dicopper(II) complexes having d(x2-y2)-d(x2-y2) magnetic orbitals show a linear magneto-structural correlation: -2J(cm(-1)) = 11.48 phi(deg) - 1373.

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Phospholipids, the major structural components of membranes, can also have functions in regulating signaling pathways in plants under biotic and abiotic stress. The effects of adding phospholipids on the activity of stress-induced calcium dependent protein kinase (CaCDPK1) from chickpea are reported here. Both autophosphorylation as well as phosphorylation of the added substrate were enhanced specifically by phosphatidylcholine and to a lesser extent by phosphatidic acid, but not by phosphatidylethanolamine. Diacylgylerol, the neutral lipid known to activate mammalian PKC, stimulated CaCDPK1 but at higher concentrations. Increase in V-max of the enzyme activity by these phospholipids significantly decreased the K-m indicating that phospholipids enhance the affinity towards its substrate. In the absence of calcium, addition of phospholipids had no effect on the negligible activity of the enzyme. Intrinsic fluorescence intensity of the CaCDPK1 protein was quenched on adding PA and PC. Higher binding affinity was found with PC (K-1/2 = 114 nM) compared to PA (K-1/2 = 335 nM). We also found that the concentration of PA increased in chickpea plants under salt stress. The stimulation by PA and PC suggests regulation of CaCDPK1 by these phospholipids during stress response.

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El presente trabajo se desarrolló en el Centro Naciones de Granos Básicos “HUMBERTO TAPIA BARQUERO” campo experimental San Cristobal, Managua en el período comprendido de Junio a Septiembre de 1990. Los factores en estudio fueron cuatro niveles de nitrógeno (0, 45, 90 y 135 Kg N/ha) y cuatro densidades poblacionales (114,000, 171,000, 228,000 y 285,000 plantas/ha), con el objetivo de determinar el efecto de le densidad poblacional y de los niveles de nitrógeno sobre el rendimiento de grano del sorgo variedad PINOLERO 1, y determinar el efecto de les Interacciones de los factores en estudio en el rendimiento de grano. El diseño empleado fue parceles divididas con arreglo de tratamientos en bloques completos al azar con cuatro repeticiones, colocando le densidad poblacional en la parcele grande y los niveles de nitrógeno en la sub-parcela. En las variables analizadas no se observaron diferencias significativas exceptuando en la variable panojas cosechadas por parcela útil donde se observó el efecto de las densidades poblacionales. Los niveles de nitrógeno no ejercieron efecto significativo en ninguna de les variables. Para obtener mayor precisión en los resultados se hicieron pruebas de contraste ortogonales para les variables estudiadas, en las cuales no se encontró diferencias significativas. Los rendimientos más ellos se obtuvieron con le interacción de la densidad poblacional de 228,000 plantas/ha con el nivel de nitrógeno de 45 kg/ha. El más bajo se obtuvo con le interacción de la densidad poblacional de 228,000 plantas/ha y el nivel de nitrógeno de 135 kg/ha.

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The Olympic Coast National Marine Sanctuary (OCNMS) continues to invest significant resources into seafloor mapping activities along Washington’s outer coast (Intelmann and Cochrane 2006; Intelmann et al. 2006; Intelmann 2006). Results from these annual mapping efforts offer a snapshot of current ground conditions, help to guide research and management activities, and provide a baseline for assessing the impacts of various threats to important habitat. During the months of August 2004 and May and July 2005, we used side scan sonar to image several regions of the sea floor in the northern OCNMS, and the data were mosaicked at 1-meter pixel resolution. Video from a towed camera sled, bathymetry data, sedimentary samples and side scan sonar mapping were integrated to describe geological and biological aspects of habitat. Polygon features were created and attributed with a hierarchical deep-water marine benthic classification scheme (Greene et al. 1999). For three small areas that were mapped with both side scan sonar and multibeam echosounder, we made a comparison of output from the classified images indicating little difference in results between the two methods. With these considerations, backscatter derived from multibeam bathymetry is currently a costefficient and safe method for seabed imaging in the shallow (<30 meters) rocky waters of OCNMS. The image quality is sufficient for classification purposes, the associated depths provide further descriptive value and risks to gear are minimized. In shallow waters (<30 meters) which do not have a high incidence of dangerous rock pinnacles, a towed multi-beam side scan sonar could provide a better option for obtaining seafloor imagery due to the high rate of acquisition speed and high image quality, however the high probability of losing or damaging such a costly system when deployed as a towed configuration in the extremely rugose nearshore zones within OCNMS is a financially risky proposition. The development of newer technologies such as intereferometric multibeam systems and bathymetric side scan systems could also provide great potential for mapping these nearshore rocky areas as they allow for high speed data acquisition, produce precisely geo-referenced side scan imagery to bathymetry, and do not experience the angular depth dependency associated with multibeam echosounders allowing larger range scales to be used in shallower water. As such, further investigation of these systems is needed to assess their efficiency and utility in these environments compared to traditional side scan sonar and multibeam bathymetry. (PDF contains 43 pages.)

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We measured spectroscopic and laser action properties of a novel 8-position substituted pyrromethene-BF2, namely 1,3,5,7-tetramethyl-2,6-diethyl-8-n-propyl pyrromethene-BF2 complex. The laser action was performed with the corresponding dye solution in ethanol, which was placed in a Littman-type laser cavity pumped by the second harmonic of a Q-switched Nd:YAG laser. The spectroscopic measurements clearly indicated that the corresponding dye solution in ethanol exhibited intense absorption in the visible spectral region with large fluorescence quantum yield. It possesses rather low triplet-triplet absorption in the spectral region 460-550 nm and almost negligible triplet-triplet absorption in the lasing spectral region. As a consequence, it lases nearly as efficiently as commercially available benchmark laser dyes such as Rhodamine-6G and outperformed them in wavelength tunability in our laser cavity and pump geometry. (C) 2002 Optical Society of America.

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Until now observations on the temporal variation of size of freshwater copepods have not provided much information. Other observers only mention in passing this or that phenomenon from which it is possible to deduct termporal variations. In this study Cyclops strenuus s.l., a freshwater species of fairly wide distribution, is studied in two water bodies. The author studies the systematic, placing of inhabitants described as C. strenuus Fischer in both locations, their annual life cycle, and their annual size variations.

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The dynamics of the fecundity of roach, with emphasis on Rutilus rutilus (L.), were studied in waters in the European parts of the USSR. This translation provides conclusions, and figures and table captions only.

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Experimental studies were carried out on the transformation of matter and energy during embryonic development of the isopod Crustacea Asellus aquaticus L. under two constant temperatures. Material for the experiments was collected in the quarry lakes of the Kurasovshchin-zone (city-Minsk) at 9°C in April and at 18°C in June, 1977. The rate of consumption of oxygen per specimen by eggs and embryos of Asellus aquaticus was observed and dynamics of the basic biological characteristics during embryonic development studied.

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The osmotic pressure of the perivitelline fluid and the yolk of trout (Salmo trutta) eggs were measured separately by the Drucker-Schrein method. The permeability of the egg membrane and the variations in the osmotic pressure of the eggs when placed in salt solutions were also investigated.

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】目的: 研究4'- 乙酰胺苯基4- 胍基苯甲酸酯(AGB)抗 HIV-1 活性及作用靶点。方法: 通过 AGB对宿主细胞的毒性实验、合胞体抑制实验、融合阻断实验、对HIV-1感染细胞的保护作用实 验和对HIV-1急性感染细胞p24抗原产生的抑制作用等试验,观察AGB对HIV-1复制的影响和作 关键词: AGB; HIV-1; 病毒进入; 杀微生物剂; 杀精子活性 中图分类号: R967; 文献标识码: A 文章编号: 0253-357X(2005)11-0660-05 本研究为国家高技术研究发展计划(2003AA219142)、国 家科技攻关计划 (2004BA719A14)、中国科学院知识创新 工程重要方向(KSCX2-SW-216; KSCX12-SW-11)、云南 省科技攻关计划(2004NG12)和云南省生育调节与少数民 族优生研究重点实验室资助项目 通讯作者: 郑永唐; Tel: +86-871-5195684; Fax:+86-871-5191823; E-mail: zhengyt@mail.kiz.ac.cn 在我国, 人免疫缺陷病毒(human immunodeficiency virus, HIV)危害日趋严重,处在全国低流行 与局部地区及特定人群高流行并存的态势。卫生部 的数据显示,截止2005 年3 月底,全国累计报告 HIV 感染者114 703 例。专家估计我国实际HIV 感 染者超过100 万人。预计到2010 年, 全国HIV感染 者将突破千万。截止2004 年底, 云南省累计报告的 HIV 感染者已达28 391 人, 是全国流行最严重的地 区。艾滋病流行正由高危人群向一般人群传播。 新的证据显示近年来由性传播途径感染的比例有所 上升, 女性感染者的比例有较大幅度的上升, 迫切需 要发展一种女性可自主控制的方法 [1]。杀微生物剂 是可以局部用药于阴道和宫颈、能够杀灭或抑制 包括HIV等病毒性和细菌性病原体、人工合成或天 然的药物。具有避孕作用的杀微生物剂更是近年 来的研究热点,也具有广阔的应用前景[2,3]。 顶体酶是存在于精子顶体内的一种类胰蛋白 酶, 它是受精过程中的一种重要的蛋白水解酶, 此酶 能水解卵细胞的透明带, 使精子能够与卵细胞相融 合; 顶体酶还能促进生殖系统中激肽的释放, 后者能 够增强精子的活力和促进精子的运动, 顶体酶的失 活将导致不孕[4]。AGB(4'- 乙酰胺苯基 4- 胍基苯甲 酸酯)是顶体酶的抑制剂, 实验表明在多种动物中有 很好的杀精子作用[5-7]。Bourimbaiar等[8]曾报道AGB 还具有体外抗HIV-1的作用, 活性较N-9高, 且毒性 较小。在本实验中, 我们发现AGB 的体外抗HIV-1 活性主要是阻断HIV-1 进入细胞。 用机制。结果: AGB抑制HIV-1IIIB诱导C8166细胞形成合胞体, EC50为39.5 μg/ml; 抑制HIV-1感染 细胞上清中HIV-1 p24抗原的表达, EC50为33.36 μg/ml; 阻断HIV-1慢性感染H9细胞与正常C8166 细胞间融合的作用。结论: AGB具有阻断HIV-1 进入宿主细胞的作用,是一种有前景的具杀精子 作用的杀微生物剂。