114 resultados para Virgilio Marón, Publio, 70-19 a. C..
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Previous studies have demonstrated that germinal vesicle of amphibian oocyte contains small nuclear ribonucleoprotein polypeptide C (SNRPC). In this study, a putative member of SNRPC was identified from Carassius auratus gibelio oocyte cDNA library. Its full-length cDNA has an open reading frame of 201 nt for encoding a peptide of 66 an, a short 5'-UTR of 19 nt and a long 3'-UTR of 347 nt including a polyadenylation signal and poly- (A) tail, and the deduced amino acid sequence has 47% identity with the C-terminal of the zebrafish small nuclear ribonucleoprotein polypeptide C. Western blot analysis revealed its oocyte-specific expression. Immunofluorescence localization indicated that its gene product localized to numerous nucleoli within the oocytes and showed dynamic changes with the nucleoli during oocyte maturation. RT-PCR and Western blot analysis further revealed its constant presence in the oocytes and in the embryos until hatching. The data suggested that the newly identified CagOSNRPC might be a nucleolar protein. (c) 2006 Elsevier Inc. All rights reserved.
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The growth and energy budget for F-2 'all-fish' growth hormone gene transgenic common carp Cyprinus carpio of two body sizes were investigated at 29.2 degrees C for 21 days. Specific growth rate, feed intake, feed efficiency, digestibility coefficients of dry matter and protein, gross energy intake (I-E), and the proportion of I-E utilized for heat production (H-E) were significantly higher in the transgenics than in the controls. The proportion of I-E directed to waste products [faecal energy (F-E) and excretory energy loss (Z(E) + U-E) where Z(E) is through the gills and U-E through the kidney], and the proportion of metabolizable energy (M-E) for recovered energy (R-E) were significantly lower in the transgenics than in the controls. The average energy budget equation of transgenic fish was as follows: 100 I-E = 19.3 F-E + 6.0 (Z(E) + U-E) + 45.2 H-E + 29.5 R-E or 100 M-E = 60.5 H-E + 39.5 R-E. The average energy budget equation of the controls was: 100 I-E = 25.2 F-E + 7.4 (Z(E) + U-E) + 35.5 H-E + 31.9 R-E or 100 M-E = 52.7 H-E + 47.3 R-E. These findings indicate that the high growth rate of 'all-fish' transgenic common carp relative to their non-transgenic counterparts was due to their increased feed intake, reduced lose of waste productions and improved feed efficiency. The benefit of the increased energy intake by transgenic fish, however, was diminished by their increased metabolism.
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The maturation pattern of sexual reproduction in Hizikia fusiformis (Harvey) Okamura (Sargassaceae, Phaeaophyta) was examined in 2003 at Yunao Bay, Nanao Island, Shantou, China. Maturation began in mid-April (seawater temperature 19-21 degrees C), reached the peak in mid-May (maturation rate ca. 70%, and seawater temperature 23.5-25 degrees C) and finished in late-June (seawater temperature 27.5-30 degrees C). The Hizikia plants continued to gain the length from the beginning of maturation season to reach a maximum mean length of 34.8 cm in mid-May, after which the mean length was reduced drastically due to the senescence and rupture of the larger plants in size. The major portion of the mature plants belonged to the larger plants between April and May, but to the smaller ones in June. It is suggested that the plant must achieve a critical size before reproductive maturation occurred. There was a positive relationship between the number of receptacles (NR), as well as the reproductive allocation (RA), and the plant size of Hizikia population, with the recorded maximum values of NR and RA being 1220 and 64.3% respectively, for a single plant.
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From 2001 to 2002, a new and emergent infectious disease of Ophiocephalus argus occurred in a fishery in Hubei Province, China, with an incidence of 60% similar to 70% and a mortality as high as 100 %. The diseased fish showed an enlarged abdomen, the millet-like nodules in internal organs, and the swollen kidney which was composed of 5 similar to 10 sarcoma-like bodies in cream or gray-white colour or ulcerated into beandregs-like substance. Light microscopic observation revealed the basophilic or acidphilic inclusions in cytoplasm of the cells and the granulomas, a diffusive chronic inflammation in internal organs. Further analysis under an electron microscope indicated that the intracytoplasmic inclusions were rickettsia-like organisms (RLOs) that are either spherical or coccoid, with variable size, ranging from 0.5 similar to 1.5 mum in diameter, and enclosed within membrane-bound cytoplasmic vacuoles. RLO had a central nucleoid region with some fine filamentous structures and an electron-dense granule. Its cytoplasm contained abundant ribosomal bodies. Occasionally, RLO appeared to be divided by binary fission. RLOs were also observed in the homogenized tissue of infected fish. The results suggested that the death of cultured O. argus was caused by RLO infection.
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Effects of V/III ratio on heavily Si doped InGaAs and InP were studied using low pressure metalorganic chemical vapor deposition (LP-MOCVD) at a growth temperature of 550degreesC. In InGaAs, as the V/III ratio decreases from 256 to 64, the carrier concentration increases from 3.0 x 10(18) to 5.8 x 10(18) cm(-3), and the lattice mismatch of InGaAs to InP was observed to vary from -5.70 x10(-4) to 1.49 x 10(-3). In InP, when the V/III ratio decreases from 230 to 92, the same trend as that in Si doped InGaAs was observed that the carrier concentration increases from 9.2 x 10(18) to 1.3 x 10(19) cm(-3). The change of AsH3 was found to have stronger effect on Si incorporation in InGaAs at lower growth temperature than at higher growth temperature. (C) 2003 Elsevier B.V. All rights reserved.
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Enhanced near-infrared photoluminescence (PL) from sulfur-related isoelectronic luminescent centers in silicon was observed from thermally quenched sulfur-implanted silicon in which additional copper or silver ions had been coimplanted. The PL from the sulfur and copper coimplanted silicon peaked between 70 and 100 K and persisted to 260 K. This result strongly supports the original conjecture from the optical detection of magnetic resonance studies that the strong PL from sulfur-doped silicon comes from S-Cu isoelectronic complexes [Frens , Phys. Rev. B 46, 12316 (1992); Mason , ibid. 58, 7007 (1998).]. (c) 2007 American Institute of Physics.
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The pressure behavior of the ultraviolet (UV) and green emission bands in ZnO tetrapod-like micro-rods has been investigated at 300 and 70 K, respectively. The pressure coefficient of the UV band at 300 K is 24.5 meV/GPa, consistent with that of the band gap of bulk ZnO. However, the pressure coefficient of the green band is 25 meV/GPa, far larger than previous literature reports. The green band in this work originates from Cu-related emission, as confirmed by the fine structure observed in the spectra at 10 K. The pressure coefficients of four phonon replicas of the free exciton emission (FX) at 70 K are 21.0, 20.2, 19.8, and 19.3 meV/GPa, respectively. The energy shift rate of the FX emission and the LO phonon energies is then determined to be 21.4 and 0.55 meV/GPa. The pressure coefficient of the neutral donor bound exciton ((DX)-X-0) transition is 20.5 meV/GPa, only 4% smaller than that of FX. This confirms that the (DX)-X-0 emission corresponds to excitons bound to neutral shallow donors. (C) 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
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Hetero-junction solar cells with an me-Si: H window layer were achieved. The open voltage is increased while short current is decreased with increasing the mc-Si:H layer's thickness of emitter layer. The highest of V-oc of 597 mV has obtained. When fixed the thickness of 30 nm, changing the N type from amorphous silicon layer to micro-crystalline layer, the efficiency of the hetero-junction solar cells is increased. Although the hydrogen etching before deposition enables the c-Si substrates to become rough by AFM images, it enhances the formation of epitaxial-like micro-crystalline silicon and better parameters of solar cell can be obtained by implying this process. The best result of efficiency is 13.86% with the V-oc of 549.8 mV, J(sc) of 32.19 mA center dot cm(-2) and the cell's area of 1 cm(2).
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The polyetherketone (PEK-c) guest-host polymer films doped with (4'-nitro)-3-azo-9-ethyl-carbazole (NAEC) were prepared. The films were poled by corona-onset poling at elevated temperature (COPET). The orientational order parameter of the chromophores NAEC in poled polymer film was determined by measuring the absorption spectra of the films before and after being poled. By using the two-level model, the measured dispersion of the refractive index of the polymer film, and the dispersion of the first hyperpolarizability of chromophore NAEC, the dispersion of the macroscopic second-order nonlinear optical (NLO) and linear electrooptic (EO) coefficients was evaluated for the NAEC/PEK-c guest-host polymer film. (C) 2001 Elsevier Science Ltd. All rights reserved.
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在实际中对C码进行API一致性检验的过程中发现,API(application programming interface)规范大都涉及以数值为论域的时序性质与在静态分析过程中所能获取的以变量符号为占位符的独立语义之间存在分析上的缺口.在仔细考察c码变量符号间等值关系的基础上,给出基于值等价类空间的等值分析方法.这种流相关的分析方法不仅可以在API一致性检验的过程中维护变量符号域和数值域之间的对应关系,而且由于能够屏蔽等值关系以外的其他信息,还可以为后继分析的优化提供有力的支持.
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The ability of the Evpatoria RT-70 radar complex to perform research on space debris was investigated in four trial experiments during 2001-2003. The echo-signals of 25 objects at geostationary, highly elliptical and medium-altitude orbits were recorded on magnetic tapes at radio telescopes in Russia, Italy, China and Poland. The multi-antenna system configuration gives potential to supplement the classic radar data with precise angular observations using the technique of Very Long Baseline Interferometry. The first stage of such processing was fulfilled by the correlator in N. Novgorod, Russia. The cross-correlation of transmitted and received signals was obtained for the 11 objects on the Evpatoria-Bear Lakes, Evpatoria-Urumqi and Evpatoria-Noto baselines. This activity also promoted developing the optical observations of geostationary objects, conducted for the improvement of the radar target ephemerides. (C) 2004 COSPAR. Published by Elsevier Ltd. All rights reserved.
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以野外样地调查和室内分析法研究了黄土丘陵区不同植被恢复年限下草地土壤微生物CN及土壤呼吸熵的变化。结果表明,土壤微生物量碳明显地随着植被恢复年限的增加而增加。在恢复前23a,土壤微生物量碳在0~20cm层年增加率为24.1%;20~40cm104.4%。植被恢复23a,0~20cm层增长率为0.83%,20~40cm0.19%。土壤微生物量N表现为在植被恢复的初期略有下降,3a,开始出现明显增加。0~20cm层年增长率为20.14%,20~40cm15.11%。在植被恢复23a,0~20cm层的年增长率为0.14%,20~40cm化不大。土壤微生物呼吸强度随着恢复年限的增加逐渐加强;土壤呼吸熵随植被封育时间的增加而呈对数降低趋势。土壤呼吸熵(qCO2)在反映土壤的生物质量变化时,显得更加稳定,受植物生长状况影响较小。相关分析表明,土壤微生物量和土壤微生物活性与土壤有机质、碱解氮和粘粒含量显著正相关;与土壤粉粒含量明显负相关;表层土壤pH值对其也有明显影响。草地植被自然恢复过程可增加土壤微生物活性,有利于土壤质量的提高。
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胞质谷胱甘肽过氧化物酶(cGPX)是生物体内重要的抗氧化含硒酶,在保护机体免受活性氧损伤方面起着重要作用,因此利用抗体酶技术进行cGPX的人工模拟具有重要意义。本文在疏水腔修饰法指导下,设计合成了两种新的具有GSH特征的半抗原Hp4和Hp5。通过单克隆抗体及化学诱变技术制备得到三种针对半抗原Hp4的含硒抗体酶和两种针对Hp5 特异的含硒抗体酶。其中SeHB5(1867 U/μmol)和SeIA7(3567U/μmol)活力达到和天然酶同一数量级,进一步验证了疏水腔修饰法。本文还对含硒抗体酶SeHB5和SeIA7的酶学性质进行了系统的研究。生物活性实验表明含硒抗体酶对不同浓度H_2O_2损伤的小鼠心肌细胞均有一定程度的保护作用。本文同时报道了三种硒代β-环糊精作为cGPX模拟物的活力,其中6,6'-(O-亚苯基)二硒基桥联-β-环糊精二聚体的活力超过目前被认为最理想的补硒试剂Ebselen。~(13)C记UDPG在利用核磁手段发现新的UDPG依赖糖基转移酶和检测新的糖基化合物,确定糖基间连接方式,合成同位素标记寡糖和多糖等方面具有广阔的应用前景。本文首次从植物培养细胞Rauvolfia serpentina四步纯化得到具有一定纯度的UDPG焦磷酸化酶,并应用该酶建立了经济,简便,高产率的从葡萄糖出发,酶法大量合成UDPG的方法。利用该方法首次合成得到0.5克级的UDP-[4-~(13)C]-glucose,产率高达~70%。在NMR谱学方面确定了UDPG中葡萄糖基上4位C归属,从而纠正了文献中关于UDPG核磁谱归属中的部分错误。
Resumo:
本工作旨在通过共聚、共混技术制备酚酞型聚芳醚砜共聚物(PP/BiS-T) PES和共混物(PPS/PES-C)PPO/PES-C以便改善酚酞型聚芳醚砜(PES-C的加工性能(特别是注射加工性能)和耐溶剂性能。通过研究共聚物和共混物的微观结构,聚集态结构与性能的关系,探索改善酚酞型聚芳醚硕性能的有效途径第一部分:(PP/BiS-T) PES共聚物的合成、结构与性能(PP/BiS-T) PES共聚物是以4,4'二氯二苯砜(DCDPS)、酚酞(PP)和4,4'-二羟基二苯硫醚(BiS-T)为单体,采用固体无水K_2CO_3/NMP/TMSO_2 混合溶剂反应体系合成的。共聚反应规律研究表明:在NMP/TMSO_2混合溶剂中,共聚反应可以顺利进行,避免了交联反应的发生,并成功地合成了高分子量的(PP/BiS-T) PES共聚物。DSC析结果表明(PP/BiS-T) PES系列属于无定形的均相共聚物体系,每一组成比例对应的共聚物只具有一个玻璃化转变温度。且随组成比例的改变呈线性变化,TBA析结果与DSC本一致,并证实了(PP/BiS-T) PES属于均相共聚物体系,而不是均聚物的共混物。TG分析表明:共聚物具有良好的耐热氧化稳定性BiS-T链节在分子链中起到了提高自身抗氧性的作用。1R光谱对共聚物的结构进行表征。~(13)C-NMR分析确认共聚物多属于无规共聚物。动态力学试验表明共聚物(PP/BiS-T) PES以及PES-C在-100 ℃附近和0-100 ℃,存在着次级松驰与转变,并发现水分子的存在对这种转变(次级松驰)有一定的影响。共聚物的熔融流动性试验和溶解性试验表明共聚物(PP/BiS-T) PES具有稍好于PES-C熔融流动性;溶解性与PES-C似。力学试验说明共聚物属于强而硬类型的聚合物。第二部分:PPS/PES-C混物的制备、聚集态结构与性能PPS/PES-C混物是以联苯/二苯硕混合物为溶剂,采用溶液沉析方法制备的,DSCWAXD,SEM和1R分析手段对共混物的聚集态结构和微观结构进行了表征。DSC析认为共混物属于多相体系,PPS的结晶性随着PES-C量增加而降低。DSCSEM观察结果表明:相转变发生在PPS占40%左右。PPS占25%时,DSC线呈现出界面相玻璃化转变温度。共混物具有良好的耐热氧化稳定性和耐热分解稳定性。微晶大小计算结果:PES-C在导致了PPS微晶大小降低。WAXD曲线表明PPS占50%,共混物中的PPS具有较好的结晶性。SEM观察发现:随着PES-C量增加,PES-C分散相(PES-C50%)变为连续相(PES-C70%)。PPS占50%或低于50%时,共混物体系不仅发生了微观相分离,而且发生了宏观相分离。M.I.指数表明共混物中PPS为连续相时,共混物具有良好的熔融流动性。溶解性试验结果:共混物具有较好的耐溶剂性。第三部分:PPO/PES-C混物的合成、结构与性能 PPO/PES-C混物系用溶液-涂膜法,以氯彷为溶剂制备的。讨论了由同一共混物溶液浓度下制备的共混物的互溶性随组成的改变而变化。DSC析结果:PPO/PES-C于部分相溶性体系。利用Fox方程推导式计算结果表明PPO在富PES-C中具有良好的分散性;而PES-C富PPO相中的分散性较差。共混物(PPO/PES-C)样经丙酮浸泡后,PPO(>50%)发生了溶剂诱导结晶现象,同时丙酮促使共混物发生完全相分离。结晶溶化热显示共混物中少量的PES-C在有利于PPO的溶剂诱导结晶。TG分析表明共混物具有良好的耐热分解稳定性和耐热氧化分解稳定性。偏光显微镜下观察到PPO球晶的存在。SEM和FT-1R分别对共混物的形态结构和微观结构进行了表征。WAXD试验证实了丙酮处理的(PPO/PES-C)70/30),(90/10)共混物中PPO的结晶性。溶解性试验表明:PPO掺入有助于 PES-C耐溶剂性提高。