Syntheses of (±)-Epoformin (Desoxyepoxydon) and (±)-Epiepoformin (Desoxyepiepoxydon)

Boron is an essential nutrient for plants, but it is toxic in excess. Transgenic rice plants expressing an Arabidopsis thaliana borate efflux transporter gene, AtBOR4, at a low level exhibited increased tolerance to excess boron. Those lines with high levels of expression exhibited reduced growth. These findings suggest a potential of the borate transporter BOR4 for the generation of high-boron tolerant rice.     

生理卫生(下册)教学参考资料(续)

第五节大脑皮层的机能——高级神經活动本节是本章也是本書的高峯,是把过去学习过有关反射作用的知識进行总結和提高,使学生能从理論上理解神经对人的意义——保持內部各器官的协調,同外界环境的统一。     

生理卫生(下册)教学参考资料(续完)

第三节祖国在防治疾病上的伟大成就这节课是在学生已掌握了传染病的基本知識的基础上来进行講授的,首先在教材里提出以血吸虫病、天花、瘧疾、黑热病、痳疯等传染病說明了新旧社会的对比;同时也说明了社会主义社会制度的优越性。我們的党和政府对于人民健康的关怀是无微不至的,并且对于各种疾病的积极防治工作加强了党的领导,及时提出了一系列的方針、政策和措施;建立了专业防治机构,培养了专业干部;結合生产发动了广大羣众来参加防治。因此在防治各种传染病的工作中取得了很大的成績。     

Structure of Poly (dT)·Poly (dA)·Poly (dT)

Abstract

The molecular structure of poly (dT)·poly (dA)·poly (dT) has been determined and refined using the continuous x-ray intensity data on layer lines in the diffraction pattern obtained from an oriented fiber of the DNA. The final R-value for the preferred structure is 0.29 significantly lower than that for plausible alternatives. The molecule forms a 12-fold right- handed triple-helix of pitch 38.4 Å and each base triplet is stabilized by a set of four Crick-Watson-Hoogsteen hydrogen bonds. The deoxyribose rings in all the three strands have C2′-endo conformations. The grooveless cylindrical shape of the triple-helix is consistent with the lack of lateral organization in the fiber.     

稀有内养囊霉(Entrophosporainfrequens(Hall)AmesetSchneider)的研究(英)

Hall（1977）首次在新西兰的土壤中发现GlomusinjtequensHall。Ames和Schneider（979）在美国的加利福尼亚再次发现了这个种。他们认为该种与无梗囊霉（Acauloryora）有相似之处,抱子都是从泡囊发育而成,但无梗囊霉的抱于是在产抱囊的侧面形成,而该种的抱子则是在产抱囊柄的内部发育而成的。为此,Ames和Schneider（197）为这个种建立起一个新属——内养囊霉属（Entrophospora）,把这个种改名为稀有内养囊霉Entrophoworam斤equens（HallAmesetSchnelder。SChellGk和Spain（1984）报道了这个属的另一个种哥伦比亚内养囊霉（Entro…     

Structures for the polynucleotide complexes poly(dA) · poly(dT) and poly(dT) · poly(dA) · poly(dT)

X-ray diffraction analyses of fibers of polydeoxyadenylic acid · polydeoxythymidylic acid show that this molecule exists as a 10-fold double-helix with axial rise per nucleotide $\text{h = 3.24}\text{to}\text{3.29}\text{A}\text{?}$. The structure is very similar to B-DNA ($\text{h = 3.37}\text{A}\text{?}$) in having C3-exo furanose rings and base-pairs positioned centrally on the helix axis, but distinctive enough to have two packing modes, neither of which has been observed for B-DNA. Although the triple-stranded poly(dT) · poly(dA) · poly(dT) also has a large value of h(3.26 Å), each of the chains is a 12-fold helix of the A-genus with C3-endo furanose rings and bases displaced several Angstrom units from the helix axis.     

The Zhoukoudian (Choukoutien) Site(英汉对照)

ＴｈｅＺｈｏｕｋｏｕｄｉａｎ（Ｃｈｏｕｋｏｕｔｉｅｎ）Ｓｉｔｅ（英汉对照）ＴｈｅＺｈｏｕｋｏｕｄｉａｎＳｉｔｅ,ｆａｍｏｕｓ“ｈｏｍｅ”ｏｆＰｅｋｉｎｇＭａｎ,ｌｉｅｓａｐｐｒｏｘｉｍａｔｅｌｙ５０ｋｉｌｏｍｅｔｒｅｓｓｏｕｔｈｗｅｓｔｏｆｔｈｅＰｅ...     

Robert (Robin) Hill (1899–1991)

Obituary

Robert (Robin) Hill (1899–1991)     

美国癌症研究所(NCI)科研规划简介(续)

3 临床治疗 3.1 临床肿瘤学拨款临床肿瘤学规划提供的拨款,支持研究治疗人类癌症中抗癌剂的应用及其效果的评估。它包括四个特殊领域:化疗药物的毒性和效果,单独激素治疗或同其它治疗方式相结合的临床研究;用动物模型和细胞系统发展治疗研究;对可能干扰抗癌药物活性,与癌有关的失调进行研究;进行癌症临床试验新方法的研究。该规划拨款还对癌症治疗时引起癌症患者承担的潜伏生命威胁处境给予支持。出血控制时的血小板转输,白血球输送,     

Synthesis of (S)-(—)-Vertinolide

(S)-(?)-Vertinolide 1 was synthesized via the tetronic acid derivative 6 from (S)-(?)-tetrahydro-2-methyl-5-oxo-2-furancarboxylic acid 3. (±)-Vertinolide was also synthesized from (±)-3.