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1.
R. Schoysman 《Andrologie》1999,9(1):48-52
Recently the word P.A.D.A.M. has been proposed to replace the term Andropause (Partiel Andrologen Deficiency in Aging Males). This implies that most if not all problems of the aging male are due to testosterone déficiency, which is not at all true when one considers the results of endocrine investigations in that group. So many other sociological and relational causes are involved that the term P.A.D.A.M. is clearly a misnomer. 相似文献
2.
《Ibis》1930,72(S1):411-413
T he two giants of the genus-that is so far as the cock birds are concerned, but, as with chiniana and a few others, their hens are so much smaller that even when in the field the two sexes are seen in company one may often doubt their being a pair of the same species. 相似文献
3.
Encephalitis is a challenging public health problem in Kern County and in the San Joaquin Valley area. During the last ten years the authors have studied the epidemiology of encephalitides due to arthropod-borne viruses and the methods used in the differential dignosis of these conditions. To incriminate a virus it is necessary to demonstrate a rise in antibody titer in the blood over a period of seven to fourteen days, the first specimen to be taken as soon as possible after onset of symptoms. A variety of tests may be necessary in some cases. Among the patients included in this presentation the greater number of those with encephalitis and also of those with poliomyelitis were under 30 years of age. The age range was five weeks to 49 years. The median annual mortality rate was 4.3 deaths per 100 cases for poliomyelitis and 3.9 for encephalitis. The greatest incidence occurred during the summer months.The clinical manifestations usually observed in encephalitis are described, but it is emphasized that wide variations and even completely atypical clinical phenomena are encountered. Four representative cases are reported and treatment is discussed. Vaccination and vector control are considered as the most promising means of combating the disease. 相似文献
4.
P.G. Moore 《Journal of experimental marine biology and ecology》1978,32(1):53-96
Analyses are given of a collection of over 65,000 amphipods derived from kelp holdfasts surveyed around Wales and S.W. England. Faunal affinity is predominantly biased latitudinally, warmwater elements being confined to the extreme southwest. Total amphipod density is related to holdfast weight. There are no significant differences in amphipod density with differences in wave exposure or turbidity. Standardized density is, however, higher in west coast than in east coast holdfasts. Diversity is lower in turbid waters due to the increased dominance of a few species. The distribution, population structure, and fecundity of the previously implicated turbidity-susceptible species, Lembos websteri Bate and Corophium bonnellii Milne Edwards are examined in the light of new ethological information. Supporting and conflicting data are examined and mechanisms are suggested to show how suspended inorganic particles could be directly detrimental to both species. In addition, indirect effects involving climatic fluctuation and competitive interactions, particularly with C. sextonae Crawford emend. Hurley and Jassa falcata (Montagu) cannot be excluded. 相似文献
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6.
本文是中国蹄盖蕨属植物研究的系列论文的第三篇,对国产轴果蹄盖蕨系植物进行了分类学订正,详细记载了中国产该系植物11种,首次将20余个名称归入该系的一些种下做为异名处理。轴果蹄盖蕨系植物是蹄盖蕨属中自然的一群,以其铁角蕨类型的孢子囊群和囊群益与其它属下类群相区别。本系植物分布于亚洲热带和亚热带山地,常见于山地常绿阔叶林下,海拔500~1800m。在华中和华东地区其分布区北界不超过长江一线。中国西南地区和台湾及日本为该系的三个分化中心。 相似文献
7.
Neurobiology of Stomotoca. I. Action systems. 总被引:1,自引:0,他引:1
The layout of nerves, muscles, and conducting epithelia is described for the simple hydrozoan medusa Stomotoca. Comparisons are drawn with Sarsia and other recently studied forms. The major action systems are those responsible for swimming, crumpling (protective involution), tentacle posture, pointing (unilateral reciprocal flexions of the manubrium and margin), and visceral movements (barely mentioned). Crumpling is a simple summating response in this species. Crumpling and pointing are considered to use the same effectors but different conduction pathways. New histological results include the demonstration of a nerve plexus running through the endodermal canal system and a nerve plexus in the ectoderm encircling the peduncle. Special attention is given to the distribution of synapses and gap junctions, as possible trasmission pathways in behavioral responses. Some details are included on organization within the marginal nerve rings. 相似文献
8.
Woutera van Iterson A. Charlotte Ruys Verduyn Sj. Lenel-Fokkema 《Antonie van Leeuwenhoek》1960,26(1):1-8
Summary In a number of strains of the three species of P.P.L.O. of human origin coccoid elements have been observed, which are Gram
positive or Gram variable and of very small size (<0.5 μ). They are able to grow in pure culture on the surface of nutrient
agar in very small colonies. Although they have bacterial characteristics, they could not be identified as known bacteria.
Agglutination tests are in favour of a serological relationship between the coccoid elements and P.P.L.O. The suggestion that
these elements might be an outside contamination is made unlikely by several observations. The supposition that P.P.L.O.s
are L forms of these coccoid elements should be considered further. 相似文献
9.
The numbers of progeny born to 355 patients with heritable polyposis of the colon and to 315 related, but normal, subjects, all old enough to have completed their families, are presented, as well as data on 432 subjects still young enough to have more children. Two main indices are used: mean family size ("genetic fitness") and the complement of the extinction probability of the line ("evolutionary fitness"), both of which suppose a steady state. Point- and interval-estimates (the latter derived by an extension of Stigler's method) are furnished. It is estimated that the probability a new mutant gene will persist is one in four for Gardner syndrome, one in 20 for familial polyposis coli, and 0 for Peutz-Jeghers syndrome. There is evidence of bimodality in family size, suggesting voluntary infertility in a proportion of subjects. The data confirm our provisional working assumption that most families are completed by the time women are in their mid-40's and men in their mid-50's. 相似文献
10.
The synthesis of three collagen model analogs is described: Ac-Ala-Gly-Pro-Ala-Gly-Pro-NHMe, Ac-Ala-Gly-Pro-Ala-Glc-Pro-NHMe, and Ac-Ala-Glc-Pro-Ala-Gly-Pro-NHMe, where Glc stands for glycolic acid. The 1H-n.m.r. properties of these compounds in dimethylsulfoxide-d6 and trifluoroethanol are described. While in DMSO-d6 the compounds are random, in TFE the glycine amide protons seem to be less solvent exposed than the other amide protons. Little difference was found in the behavior of the three compounds. 相似文献
11.
J A Dennis 《International journal of radiation biology and related studies in physics, chemistry, and medicine》1976,29(4):323-342
Biological results, including statistical features, are described for the irradiation of Tradescantia occidentalis with 250 kVp X-rays, cobalt-60 gamma-radiation and monoenergetic neutrons with energies between 0-08 and 15 MeV. The effect studied was that of the induction of pink sectors in the otherwise blue staminal hairs of the flowers at low doses of radiation. Statistical aspects of the results suggest that a fraction of the asynchronous cell population in the hairs is very sensitive to neutron radiation, but not necessarily to lower LET radiations. All the results were fitted by a least-squares method by polynomials of different degrees. Best fits to X- and gamma-ray data were provided by second-degree polynomials, and to the neutron data by either second- or third-degree polynomials. Limiting r.b.e. and o.e.r. values at low doses are derived. Some computed microdosimetric parameters are presented in comparison with the r.b.e. values. It is concluded that the effect studied is complex and may not provide a critical test of bio-physical theories of radiation effects. 相似文献
12.
Zhang Xian-chun 《植物分类学报:英文版》1996,34(2):180-193
This paper,third in the series of an account of the genus Athyrium in China, presents a revision of the series Epiraches Ching et Y.T.Hsieh ex Y.T.Hsieh.A total of 11 species are recognized from China,and more than 20 names are reduced to synonyms in the present paper.Ser.Epiraches is anatural group in Athyrium,it is distinguished from all the other groups of the genus by its Asplenioid sori and indusia,The series is entirely Asian tropical,subtropical and primarily montane.Its northern limits in central and eastern China are not beyond the Yangtze River.Southwestern part and Taiwan of China and Japan Islands are centers of diversity for the series,each with more than five species.Some speciesare disjunctly distributed in southwest China-Taiwan-Japan;one species(Athyrium roseum) occurs discontinuously between Yunnan and Taiwan;one endemic to Hainan(A. hainanense)is the only representative of Athyrium on the island.All members of this series grow in evergreen broad-leaf forests,generally from 500 to 1800 m above sea level.A key to the species,and illustrations of the middle pinnae from different specimens are provided. 相似文献
13.
Investigations dealing with the characteristics of chromosomal apparatus at late stages of ontogenesis are analyzed. Both structural and functional changes in the chromosomal apparatus are observed in ageing. Some papers indicate to the association of certain variants of chromosomal polymorphism with the longevity "phenomenon". 相似文献
14.
Glycopeptide dendrimers are branched structures containing both carbohydrates and peptides. Various classes of these compounds differing in composition and structure are mentioned, together with their practical use spanning from catalysis, transport vehicles to synthetic vaccines. The main stress is given to glycopeptide dendrimers, namely multiple antigen glycopeptides (MAGs). In MAGs, the core, branches or both are composed of amino acids or peptides. Other classes of glycodendrimers (PAMAM, polypropylene imine, cyclodextrin, calixarene, etc.) are mentioned too, but to a smaller extent. Their syntheses, physicochemical properties and biological activities are given with many examples. Glycopeptide dendrimers can be used as inhibitors of cell surface protein-carbohydrate interactions, intervention with bacterial adhesion, for studying of recognition processes, diagnostics, imaging and contrast agents, mimetics, for complexation of different cationts, as site-specific molecular delivery systems, for therapeutic purposes, as immunodiagnostics and in drug design. Biomedical applications of glycopeptide dendrimers as drug and gene delivery systems are also given. 相似文献
15.
Infrared and X-ray diffraction studies have established that in the β-precipitation region of poly-L -glutamic acid the chains are in the β-conformation. Therefore, a major molecular conformational change has taken place upon precipitation. It is shown that the size of the α-helical aggregates remains constant with time in the β-region. Strong evidence can be offered to indicate that the transformation involves a transitory random-coil intermediate. Reasons are advanced, in view of the stability of the β-form, as to why two distinct precipitation regions exist. 相似文献
16.
W Flossmann E Westhof A Müller 《International journal of radiation biology and related studies in physics, chemistry, and medicine》1975,28(2):105-115
Radicals produced by X-irradiation at 77 K of 1-methyluracil. HBr crystals have been analysed by electron spin resonance spectroscopy. The results are compared with those obtained on 1-methyluracil crystals. Four radicals have been identified, two of which are present only in 1-methyluracil. HBr crystals: the C6-addition radical and the pyrimidine--anion radical. Warming-up experiments have been performed in order to study the secondary radical reactions. The different mechanisms proposed for the radiolysis of DNA constituents in the solid state are discussed in connection with these findings. 相似文献
17.
M D Ionescu G Mih?escu G Mencinicopschi 《Roumanian archives of microbiology and immunology》1991,50(1):27-35
Under lysozyme action a minicell-forming line (I.C.A.-1.65) of B. subtilis releases protoplasts. The main cytologic events which proceed protoplast releasing are described. Different areas of the cell wall prove a remarkable difference in their sensitivity to enzymatic lysozyme action. Central areas of the cell wall are most sensitive and the polar areas are most resistant. Mesosomal vesicles and tubules are extruded and released together with other cytoplasmic extrusion during the protoplasting process. The cell wall of minicells does not prove resistance particularities to lysozyme action. The minicells release protoplasts. 相似文献
18.
Robert Ornduff Theodore Mosquin Donald W. Kyhos Peter H. Raven 《American journal of botany》1967,54(2):205-213
Chromosome counts are reported for 76 taxa and 2 natural hybrids of tribe Senecioneae (Compositae). First counts are reported for several species of Senecioneae as well as for the genera Cadiscus and Whitneya. New chromosome numbers are added to those previously known in Arnica, Cacalia, and Senecio. Additional counts from Arnica support our previous suggestion that x = 19 for this genus. It is assumed that observed meiotic irregularities are associated with apomixis in this genus. Basic chromosome numbers for various New World sections of Senecio are proposed, and certain problems of sectional relationships in this genus are discussed. Chromosome numbers and plant morphology of Cadiscus, Hulsea, and Whitneya indicate that these genera should be removed from Helenieae to Senecioneae. The possible affinity of the anomalous genus Adenocaulon with Mutisieae is discussed. Data presented in the paper further support our earlier proposal that the basic chromosome number for Senecioneae is x = 10. 相似文献
19.
Profiles of negatively stained gap junctions have been measured by grid sectioning. After normal levels of electron irradiation, the membrane thickness shrinks to about half that of unirradiated controls, but no shrinkage occurs in the hexagonal lattice plane. Even under low irradiation conditions, there is significant thinning of the membranes. Edge views, in which rows of connexons are aligned parallel to the beam, were obtained from grid sections, folds in normal negatively stained specimens, and sections of a positively stained specimen. Averaging these micrographs with the translational and mirror symmetry of the projected lattice image displays conserved and variable features in the stain distribution of different specimens. Variations in the relative amount of negative stain in the gap at the surfaces and in the channel are uncorrelated with the irradiation but appear to depend on the local staining conditions and the integrity of the connexons. The dimensions measured from previously unirradiated grid sections, folds, and positively stained sections are in accord with x-ray diffraction measurements. Radiation-induced shrinkage can be accounted for by mass loss principally from the membrane bilayer. Disordering of the surface structure appears to be correlated with the radiation sensitivity of the bilayer; in contrast, the gap structure is well preserved under a variety of conditions. 相似文献
20.
It has been shown that extracellular proteinases synthesized by a keratinolytic strain of S. fradiae are characterized by diversified activity in the decomposition of both proteins and synthetic substrates. Among the six proteinases isolated, apart from the ones dominating and having relatively low specificity, there are two enzymes characterized by narrow catalytic abilities--extremely similar to those of trypsin. These proteinases intensively degraded all the trypsin substrates studied, but they were inactive or showed slight activity toward others. They were also highly sensitive to such specific inhibitors of trypsin as TLCK, SBTI and TIO. 相似文献