极小(C_4,K_5;11)-平面图

若n阶平面图G的任一子图都不与H_1同构,且G的任一子图都不与H_2同构,则G称为(H_1,H_2;n)-平面图;平面Ramsey数指不存在(H_1,H_2;n)-平面图的最小n。本文利用对称性及反证等方法,得到了所有的极小(C_4,K_5;11)-平面图,有助于证明平面Ramsey数。     

Identification of 3α, 17α, 21-trihydroxy-5α-pregnane (allotetrahydro-17α-hydroxy-cortexone) and 3α,21-dihydroxy-5α-pregnane (allo-tetrahydro-cortexone) in human urine

Résumé Le 3, 17, 21-trihydroxy 5-pregnane (allo-tétrahydro-17-hydroxy-cortexone) et le 3,21-dihydroxy 5-prégane (allo-tétrahydro-cortexone) ont été identifiés dans l'urine humaine. Ces composés avaient les mêmes migrations chromatographiques avant ou après acétylation ou oxydation que les respectifs stéroïdes de synthèse.     

(−)-Maalian-5-ol,a new enantiomeric sesquiterpenoid from the liverwortPlagiochila ovalifolia

Summary A new enantiomeric sesquiterpene alcohol named (–)-maalian-5-ol was isolated from the liverwort, and the structure and absolute configuration was determined to be the stereostructureI by chemical and spectral evidence.The authors express their gratitude to Dr H. Inoue, National Science Museum, for identification of the liverwort, and Prof. T. Tokoroyama, Osaka City University, for sending of the data of (–)--maaliene and (+)-selina-5,11-diene. Thanks are also due to the Ministry of Education for financial support of this work.     

The ‘mauve factor’ of schizophrenia and porphyria, 5-hydroxyhaemopyrrole lactam,has low pharmacological potency on guinea-pig ileum

Summary 5-Hydroxyhaemopyrrole lactam, the mauve factor reported in the urine of schizophrenics and porphyrics was found to inhibit electrically-stimulated contractions of guinea-pig ileum only at high concentrations (ID₅₀=8.5 mM). This low potency makes it unlikely that the compound can account for neurotoxic effects in human porphyria.We thank the Wellcome Trust for a grant.     

eIF2A,an initiator tRNA carrier refractory to eIF2α kinases,functions synergistically with eIF5B

The initiator tRNA (Met-tRNA _i ^Met ) at the P site of the small ribosomal subunit plays an important role in the recognition of an mRNA start codon. In bacteria, the initiator tRNA carrier, IF2, facilitates the positioning of Met-tRNA _i ^Met on the small ribosomal subunit. Eukarya contain the Met-tRNA _i ^Met carrier, eIF2 (unrelated to IF2), whose carrier activity is inhibited under stress conditions by the phosphorylation of its α-subunit by stress-activated eIF2α kinases. The stress-resistant initiator tRNA carrier, eIF2A, was recently uncovered and shown to load Met-tRNA _i ^Met on the 40S ribosomal subunit associated with a stress-resistant mRNA under stress conditions. Here, we report that eIF2A interacts and functionally cooperates with eIF5B (a homolog of IF2), and we describe the functional domains of eIF2A that are required for its binding of Met-tRNA _i ^Met , eIF5B, and a stress-resistant mRNA. The results indicate that the eukaryotic eIF5B–eIF2A complex functionally mimics the bacterial IF2 containing ribosome-, GTP-, and initiator tRNA-binding domains in a single polypeptide.     

Isolement et identification du 5β-prégnane 11β, 17α, 21-triol 3, 20-dione (Dihydrocortisol) dans l'urine humaine

Summary 5-pregnane 11, 17, 21-triol 3, 20-dione (dihydrocortisol) has been isolated and identified in the urine of patients with feminizing adrenal cortical cancer. This steroid showed the same Rf as synthetic dihydrocortisol in six different chromatographic systems. After acetylation, its Rf was the same as that of 21 monoacetate of dihydrocortisol. After bismuthic or chromic oxydation, it had the same chromatographic Rf as 5-androstane 11-ol 3, 17-dione and 5-androstane 3, 11, 17-trione respectively. After chromic oxydation of its acetate, the Rf was the same as that of 21 monoacetate of cortisone.     

Testicular Δ5-3β dehydrogenase,ascorbic acid and dehydroascorbic acid in actinomycin D-treated toads

Summary Unilaterally intratesticular injection of actionomycin D in toad inhibited ⁵-3 dehydrogenase activity with significant increase of dehydroascorbic acid and decrease of ascorbic acid level in the testis.Acknowledgments. Thanks are due to Prof. C. Deb, Department of Physiology, Calcutta University, for his suggestions and constant encouragment. Thanks are also extended to Mr R.K. Bhattacharya Microphotographer Department of Physiology, for his kind cooperation.     

Synthesis ofO 1.5-(β-D-galactopyranosyl) [DMet2, Hyp5] enkephalin amide,a new highly potent analgesic enkephalin-related glycosyl peptide

Summary A new series of O-glycosyl enkephalins has been prepared, following a convergent strategy, with high chemical yields. The galactosyl analogue,O ^1.5-(-D-galactopyranosyl) [DMet², Hyp⁵] enkephalin amide proved to be one of the most potent in vivo opioid agonists synthesized up to now.     

AMP deaminase, 5′-nucleotidase and adenosine deaminase in rat myocardial tissue in myocardial infarction and hypothermia

Summary AMP deaminase, 5-nucleotidase and adenosine deaminase have been estimated in skeletal muscle and myocardial tissue in normal rats and in rats subjected to experimental myocardial infarction or hypothermia. A difference in the enzyme distribution was found between the right and left ventricles in the normal rat. A decrease in the activity of 5-nucleotidase and an increase in the activity of adenosine deaminase were observed in infarcted myocardial tissue. The activity of all 3 enzymes was found to be depressed in the myocardium in rats subjected to hypothermia. These results are discussed in relation to adenosine production and its beneficial effects.     

Regional pattern and heat-resistance of brain 5′-deoxy-5′-methylthioadenosine phosphorylase

Summary The distribution of 5-deoxy-5-methylthioadenosine (MTA) phosphorylase in 10 pig brain areas was determined. The observed regional differences of the enzymatic activity seem to reflect more the pattern of brain spermine distribution rather than that of spermidine. Moreover, comparative studies on the heat-resistance of MTA phosphorylase extracted from the whole brain of various species suggest structural differences in the enzyme molecules occurring in the brains of different animals.     

Effects of duration of gonadectomy,sex and age on adrenal steroid 5α-reductase activity in the rat

Summary Within 6–8 weeks, gonadectomy in male and female rats leads to an increase in adrenal 5-steroid reductase activity. However, long-term post-orchiectomy enzyme activity decreases to the control level and this effect is not related to the age of animals.Supported in part by grant No.564/VI from Polish Academy of Sciences. Generous gift of hormones applied in these studies from The Upjohn Company, Kalamazoo, Michigan, USA is acknowledged.     

Fever produced in rabbits by N6, O2′-dibutyryl adenosine 3′, 5′-cyclic monophosphate

Zusammenfassung Die Injektion von N⁶-2-O-Dibutyryl-adenosin-3 5-monophosphat in den lateralen Hirnventrikel von Kaninchen führt zu einer langanhaltenden Fieberreaktion, was vermuten lässt, dass zyklisches Adenosin-35-monophosphat als weiterer Mediator in der Genese des Fiebers fungiert.     

Synthesis of 5′-deoxypyridoxal derivatives

Summary A convenient synthesis of 5-deoxypyridoxal derivatives is described. The method involves catalytic hydrogenolysis of the corresponding 5-phosphorylated derivatives; products are obtained in high yields.Supported by PHS Grant No. 5429-16-9.     

IgG purification to measure the level of an iodinated thyroglobulin peptide,the 3,5,3′,5′ tetraiodo-l-tyrosyl-l-tyrosine in human serum

Summary Antibodies reacting with 3,5,3,5 tetraiodo-l-tyrosyl-l-tyrosine (I₂Tyr-I₂Tyr) were elicited in rabbits by immunization with an oxidized yeast conjugate coupled with I₂Tyr-I₂Tyr. Ion-exchange chromatography was used to purify immunoglobulins, in order to improve the specificity in measurement of I₂Tyr-I₂Tyr level in patient serum. IgG binding capacity versus I₂Tyr-I₂Tyr was considerably increased after immunoglobulin purification.Acknowledgments. The authors with to thank Mrs M. Ollier for her valuable technical assistance.     

Physics,metaphysics, dispositions,and symmetries – À la French

Recent philosophy has paid increasing attention to the nature of the relationship between the philosophy of science and metaphysics. In The Structure of the World: Metaphysics and Representation, Steven French offers many insights into this relationship (primarily) in the context of fundamental physics, and claims that a specific, structuralist conception of the ontology of the world exemplifies an optimal understanding of it. In this paper I contend that his messages regarding how best to think about the relationship are mixed, and in tension with one another. The tension is resolvable but at a cost: a weakening of the argument for French's structuralist ontology. I elaborate this claim in a specific case: his assertion of the superiority of a structuralist account of de re modality in terms of realism about laws and symmetries (conceived ontologically) over an account in terms of realism about dispositional properties. I suggest that these two accounts stem from different stances regarding how to theorize about scientific ontology, each of which is motivated by important aspects of physics.     

γ-Glutamyltranspeptidases: sequence, structure, biochemical properties, and biotechnological applications

γ-Glutamyltranspeptidases (γ-GTs) are ubiquitous enzymes that catalyze the hydrolysis of γ-glutamyl bonds in glutathione and glutamine and the transfer of the released γ-glutamyl group to amino acids or short peptides. These enzymes are involved in glutathione metabolism and play critical roles in antioxidant defense, detoxification, and inflammation processes. Moreover, γ-GTs have been recently found to be involved in many physiological disorders, such as Parkinson's disease and diabetes. In this review, the main biochemical and structural properties of γ-GTs isolated from different sources, as well as their conformational stability and mechanism of catalysis, are described and examined with the aim of contributing to the discussion on their structure-function relationships. Possible applications of γ-glutamyltranspeptidases in different fields of biotechnology and medicine are also discussed.     

An antagonism between 3–4 dioxyphenylalanine (DOPA) and 5-hydroxytryptophan (5-HTP)

Riassunto Recentemente è stata formulata l'ipotesi che la 5-idrossitriptamina e la noradrenalina agiscano come mediatori a livello del S.N.C. I risultati ottenuti dall'A. dimostrano che la diossifenilalanina può antagonizzare il potenziamento della narcosi barbiturica indotto dal 5-idrossitriptafano.

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Research fellow from Keio University, Tokyo (Japan).     

5G移动通信发展趋势与若干关键技术

第5代移动通信系统(5G)是面向2020年之后的新一代移动通信系统,其技术发展尚处于探索阶段.结合国内外移动通信发展的最新趋势,本文对5G移动通信发展的基本需求、技术特点与可能发展途径进行了展望,并分无线传输和无线网络两个部分,重点论述了富有发展前景的7项5G移动通信关键技术,包括大规模天线阵列、基于滤波器组的多载波技术、全双工复用、超密集网络、自组织网络、软件定义网络及内容分发网络.本文还概括性地介绍了国内5G移动通信的相关研发活动及其近期发展目标.     

Identification du glucosiduronate de 5β-pregnane 3α, 21-diol 20-one (THDOC) après administration de cortexone

Summary After administration of cortexone to a normal man, we isolated the 5-pregnana 3, 21-diol 20-one glucuronide in human urine. We found 90% of this corticosteroid in the glucuronide fraction; the remaining 10% was in the free fraction.We found neither the cortexone nor its metabolites dior tetrahydrogenated in the ester-sulphate fraction.The tetrahydrocortexone-glucuronide was identified by paper chromatography and by electrophoresis.