119 resultados para 14-135


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用ApaI、AvaII、BamHI、BclII、ClaI、EcoRV、HindIII、HpaI、KpnI、PstI、PvuII、XbaI、XhoI等14种内切酶,分析了12头藏绵羊mtDNA的限制性片断长度多态性,共检测出35个酶切位点,发现AvaII、ClaI、PvuII三种酶切类型具有多态性。根据不同个体的mtDNA的酶切类型,发现藏绵羊存在三种mtDNA单倍型,计算mtDNA多态度#phi#值为0.0012,表明藏绵羊mtDNA多态性比较贫乏。

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Microphthalmia is a clinically and genetically heterogeneous disorder of eye development. The genetic basis of nonsyndromic microphthalmia is not yet fully understood. Previous studies indicated that disease pedigrees from different genetic backgrounds co

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对茶茸毒蛾进行了形态特征研究,包括从卵、幼虫、蛹、成虫各个发育时态的形态特征;成虫的头、胸、腹、腿、翅脉的特征,特别是外生殖器的结构和形态特征作了描述并附了特征图。

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用胜红蓟、黄花蒿、青蒿、艾蒿、鬼针草、三叶鬼针草、鱼眼草、小鱼眼草、紫茎泽兰、千里光、希莶草、万寿菊、肿柄菊、苍耳等14种菊科植物的石油醚、氯仿、丙酮、乙醇、甲醇和水提取物对菜青虫5龄幼虫的生测结果表明,黄花蒿、青蒿、艾蒿、鱼眼草、小鱼眼草、紫茎泽兰、万寿菊等7种菊科植物甲醇和乙醇提取物具有较高的杀虫活性。此结果为进一步从菊科植物中提取、分离和筛选高活性杀虫活性成分奠定了基础。

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利用14C标记1,2,7,8-四氯代二苯并二噁英(1,2,7,8Tetrachloro[U—14C]dibenzodioxin,14C1,2,7,8TCDD)初步研究了其在鲤体内的分布和代谢规律。14C1,2,7,8-TCDD溶解于丙酮/植物油中,腹腔暴露。暴露1、2、4、8、12d后取样,肝脏、胆汁、腹腔脂肪等消化制样后用液闪仪测量放射性活度。肝脏和胆汁内的放射性活度同步变化,都是第8d达到峰值后下降。腹腔脂肪内1—2d放射性明显高于随后取样的样品。肝和腹腔脂肪的分布量之比呈现“S”型变化趋势。暴露4d

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对淡水生态系统的重要性及生态系统服务的内涵进行了阐述 ,指出了当前淡水生态系统服务研究的不足 ;认为淡水生态系统服务的正常发挥离不开一个健康的生态系统 ,但少有将两者结合的综合研究 ,而这样的研究又是必要的 .水资源应明确包括水量、水质、水能和水生生物四大要素 ,以此为基础 ,对淡水生态系统服务及其评价指标体系进行了论述 ,并简要介绍其评价方法 .文章还对国内相关研究的思路及其技术路线进行了探讨 .

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本文研究了一浅水草型湖泊──扁担塘中桡足类的群落结构,包括种类组成、种群动态及现存量。在一周年的研究中,共发现14种浮游桡足类(9种剑水蚤和5种哲水蚤)。根据年平均密度,剑水蚤的优势种为:Mesocyclops notius,Cyclops vincinuis vincinus和Thermocyclops brevifurcatus,而哲水蚤的优势种为Meodiaptomus yantsekiangensis和Sinocalanus dorrii。通过比较长江沿岸的5个湖泊的桡足类的种类组成发现,桡足类的

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本文是根据云南星云湖、杞麓湖中所产大头鲤进行一些生态习性的研究。大头鲤的年龄鉴定是依据鳞片上环片切割现象。依星云湖的标本实测平均体长,Ⅰ龄为135.12毫米,Ⅱ龄鱼为196.93毫米,Ⅲ龄鱼为241.92毫米,Ⅳ龄焦为288毫米。星云湖和杞麓湖大头鲤体长和体重的关系式分别为:W=0.00001283L~(3.0719),W=0.00002181L~(2.9895)。食性极为单纯,主要是以枝角类和桡足类为食。不同大小个体的食性差异不大。Ⅰ龄鱼部分达到性成熟,Ⅱ龄鱼全部性成熟。其中性成熟最小个体雌鱼体长为14

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Apo-14 is a fish-specific apolipoprotein and its biological function remains unknown. In this study, CagApo-14 was cloned from gibel carp (Carassius auratus gibelio) and its expression pattern was investigated during embryogenesis and early larval development. The CagApo-14 transcript and its protein product were firstly localized in the yolk syncytial layer at a high level during embryogenesis, and then found to be restricted to the digestive system including liver and intestine in later embryos and early larvae. Immunofluorescence staining in larvae and adults indicated that CagApo-14 protein was predominantly synthesized in and excreted from sinusoidal endothelial cells of liver tissue. Morpholino knockdown of CagApo-14 resulted in severe disruption of digestive organs including liver, intestine, pancreas and swim bladder. Moreover, yolk lipid transportation and utilization were severely affected in the CagApo-14 morphants. Overall, this data indicates that CagApo-14 is required for digestive system organogenesis during fish embryogenesis and larval development.

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A novel fish-specific apolipoprotein (apo-14 kDa) has been recently cloned from eel and pufferfish. However, its expression pattern has not been elucidated. in this study, EcApo-14 has been screened from hypothalamic cDNA library of male orange-spotted grouper, which shows 62.9%, 51%, 46.9%, 43.2%, and 31.9% identities to Apo-14 of European flounder, pufferfish, Japanese eel, gibel carp, and grass carp, respectively. RT-PCR analysis reveals that this gene is first transcribed in neurula embryos and maintains a relatively stable expression level during the following embryogenesis. EcApo-14 transcripts are at a very high level during embryonic and early larval development in the yolk syncytial layer (YSL), and decrease in YSL and form intense staining in liver at 3 days after hatching. In adult tissues, EcApo-14 is predominantly expressed in liver and brain. The data suggested that EcApo-14 might play an important role in liver and brain morphogenesis and growth. (c) 2005 Elsevier Inc. All rights reserved.

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Test strip detectors of 125 mu m, 500 mu m, and 1 mm pitches with about 1 cm(2) areas have been made on medium-resistivity silicon wafers (1.3 and 2.7 k Ohm cm). Detectors of 500 mu m pitch have been tested for charge collection and position precision before and after neutron irradiation (up to 2 x 10(14) n/cm(2)) using 820 and 1030 nm laser lights with different beam-spot sizes. It has been found that for a bias of 250 V a strip detector made of 1.3 k Ohm cm (300 mu m thick) can be fully depleted before and after an irradiation of 2 x 10(14) n/cm(2). For a 500 mu m pitch strip detector made of 2.7 k Ohm cm tested with an 1030 nm laser light with 200 mu m spot size, the position reconstruction error is about 14 mu m before irradiation, and 17 mu m after about 1.7 x 10(13) n/cm(2) irradiation. We demonstrated in this work that medium resistivity silicon strip detectors can work just as well as the traditional high-resistivity ones, but with higher radiation tolerance. We also tested charge sharing and position reconstruction using a 1030 nm wavelength (300 mu m absorption length in Si at RT) laser, which provides a simulation of MIP particles in high-physics experiments in terms of charge collection and position reconstruction, (C) 1999 Elsevier Science B.V. All rights reserved.

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We have demonstrated a two-color quantum well infrared photodetector (QWIP) exhibiting simultaneous photoresponse with cutoff wavelengths at 11.8 and 14.5 mu m, respectively. Strong photocurrent signals are observed at temperature of 77 K. The simultaneous two-color photoresponse is achieved by utilizing a simple design by broadening the width of the quantum well and selecting an appropriate doping density. The two peaks are attributed to the intersubband transitions from the ground state to the first excited state (bound state) and to the fifth excited state (continuum state), respectively.

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本文在溶液理论的基础上,用纯热力学方法研究了中性磷萃取剂-金属体系(TBP-Er(no_3)_3)和氨化P_(50)-金属体系(P_(50)-cus04)的平衡计算模型。对于TBP体系有下列萃取平衡Er(NO_3)_3 (a) + 3TBP_((0)) <-> Er(NO_3)_3. 3TBP_((0))对于氨化P50体系,在萃取剂大量过量下有下的平衡Er(NO_3)_3 (a) + 3TBP_((0)) <-> Er(NO_3)_3. 3TBP(0)对氧化P50体系,在萃取剂大量过量下有下的平衡Cu_((a))~(2+) + partial deriv H_2R_2_((0)) <-> Cu(HR_2)_2 + 2H~+。用Scatchard-hildebrand模型预测了C_6H_(24)-TBP二元体系的担力学性质,以近似地用于H_2O - 16H_4 - TBP三之体系,减少了实验工作量。用气相色谱法求得了三之体系H_2O - (6H_(14) - P_(50))的热力学平衡数据,由于改进了进样系统,使实验误差<2%。对二体系的水相,均采用Pitzer理论求算γ_(Er(WO_3)_3),和γ_(Cn~(2+))。对有机相,用热力学关系求出了水,正已烷,萃取剂,的活度系数。实验结果用Scatchard-Hildebrand模型进行关联。使计算机上进行回归处理,求得萃取反应的热力学平衡常数Ka和萃合物的活度系数。计算中,将有效平衡常数进一步分解,以提出显函数项,并在图解数分中改进了计算方法,使得每条萃取等温成都解得到合理的积分值。Schatchard-Hildebrand模型能在较宽的有机相浓度区域应用。所得到的端值常数,可定性地分析各组分的相互作用。