光纤位移传感器在77和4.2 K下的输出特性研究

介绍了一种可用于低温装置内的补偿式光纤位移传感器(CFODS),讨论了该传感器在低温下的输出特性并在液氮温度(77 K)和液氦温度(4.2 K)下进行了实验研究.结果表明,该传感器在液氮温度下的灵敏度0.311 mm~(-1),高于液氦温度下的灵敏度0.278 mm~(-1).

两种不同穗型水稻品种灌浆期间物质生产特性的比较

选用直立穗型水稻品种辽粳 32 6和弯曲穗品种奥羽 316 ,在相同栽培条件下 ,比较两品种灌浆期间物质生产与分配、群体生长率 (CGR)、净同化率 (NAR)及与物质生产密切相关的叶绿素含量、叶面积指数 (LAl)、比叶重等指标。结果表明 ,和弯曲穗品种奥羽 316相比 ,直立穗品种辽粳 32 6在灌浆后期仍能保持较强的物质生产能力 ,其抽穗后生产的干物质量占其生物产量的 5 3.77% ,比其经济产量高出 12 %。灌浆期间 ,直立穗品种辽粳 32 6的比叶重较高 ,叶绿素含量较高 ,LAI下降较慢 ,各项生理指标优于弯曲穗品种奥羽 316。抽穗后 ,直立穗品种辽粳 32 6具有比弯曲穗品种奥羽 316更强的生产能力 ,因而更符合高产栽培的需要。

Cloning of hypoxia-inducible factor 1 alpha cDNA from a high hypoxia tolerant mammal - plateau pika (Ochotona curzoniae)

Hypoxia-inducible factor I is a transcription factor composed of HIF-1alpha and HIF-1beta. It plays an important role in the signal transduction of cell response to hypoxia. Plateau pika (Ochotona curzoniae) is a high hypoxia-tolerant and cold adaptation species livin only at 3000-5000m above sea level on the Qinghai-Tibet Plateau. In this study, HIF-1alpha cDNA of plateau pika was cloned and its expression in various tissues was studied. The results indicated that plateau pika HIF-1alpha cDNA was highly identical to those of the human (82%), bovine (89%), mouse (82%), and Norway rat (77%). The deduced amino acid sequence (822 bp) showed 90%, 92%, 86%, and 86% identities with those of the human, bovine, house mouse, and Norway rat, respectively. Northern blot analyses detected two isoforms named pLHIF-1alpha and pSHIF-1alpha. The HIF-1alpha mRNA was highly expressed in the brain and kidney, and much less in the heart, lung, liver, muscle, and spleen, which was quite different from the expression pattern of mouse mRNA. Meanwhile, a new variant of plateau pika HIF-1alpha mRNA was identified by RT-PCR and characterized. The deduced protein, composed of 536 amino acids, lacks a part of the oxygen-dependent degradation domain (ODD), both transactivation domains (TADs), and the nuclear localization signal motif (NLS). Our results suggest that HIF-1alpha may play an important role in the pika's adaptation to hypoxia, especially in brain and kidney, and pika HIF-1alpha function pattern may be different from that of mouse HIF-1alpha. Further-more, for the high ratio of HIF-1alpha homology among the animals, the HIF-1alpha gene may be a good phylogenetic performer in recovering the true phylogenetic relationships among taxa. (C) 2004 Elsevier Inc. All rights reserved.