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1.
Bronchial asthma in children may be difficult to diagnose. Education of the parents regarding allergic conditions, specifically bronchial asthma, is exceedingly important in order to assure satisfactory treatment and clinical results.Chest symptoms of unexplained origin in early life should immediately arouse suspicion of allergic disease. Other causes of asthmatic symptoms must be borne in mind and excluded before a positive diagnosis of bronchial asthma is established.Of the many factors to be considered in investigating a child with asthma, a comprehensive history is most essential. The climate to which the patient is exposed and the psychic influences must be taken into account. Physical examination, x-ray films and laboratory procedures should be carefully executed. Skin testing, especially with food allergens, should not be relied upon to give all the information in allergic disease. Some form of diet trial, such as elimination diets, should be used if sensitivity to food is suspected.  相似文献   

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Highland populations of several Drosophila species in Argentina were active early in the afternoon in the field as opposed to populations from a much warmer lowland site, where flies were mainly active in the early evening prior to sunset. For one of these species, Drosophila buzzatii, we tested for a genetic component of activity differences by carrying out crosses within and between populations and measuring oviposition activity of the progeny in the laboratory. We found that activity in the highland population exceeded that in the lowland one during the midafternoon, whereas activity in the lowland population exceeded that in the highland one prior to the beginning of the dark period. Oviposition activity for the period corresponding to the field observations was regressed on the proportion of the genome derived from the highland population. This variable significantly predicted oviposition activity between 1400 and 1600 and between 2000 and 2200 h. Activity of both reciprocal crosses was intermediate and not significantly different from each other, suggesting that nuclear genetic, rather than cytoplasmic factors contribute to differences in oviposition activity between the populations. Two morphological, one genetic, and one stress resistance trait were also scored to examine whether temperature differences between environments were associated with other differences between populations. Wing length of wild-caught and laboratory-reared flies from the highland population significantly exceeded that in the lowland. Thorax length of laboratory-reared flies from the highland population also significantly exceeded that from the lowland. Chromosomal inversion frequencies differed significantly between the two populations with a fivefold reduction in the frequency of arrangement 2st in the highland as compared to the lowland population. This arrangement is known for its negative dose effect on size, and thus, the highland population has experienced a genetic change, perhaps as a result of adaptation to the colder environment, where body size and the frequency of arrangement 2st have changed in concert. Finally, a heat knockdown test revealed that the lowland population was significantly more resistant to high temperature than the highland one. In conclusion, we suggest that temperature has been an important selective agent causing adaptive differentiation between these two populations. We also suggest that the activity rhythms of the two populations have diverged as a consequence of behavioral evolution, that is, through avoidance of stressful temperatures as a mean of thermal adaptation.  相似文献   

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Hurst SA 《Bioethics》2008,22(4):191-202
Despite broad agreement that the vulnerable have a claim to special protection, defining vulnerable persons or populations has proved more difficult than we would like. This is a theoretical as well as a practical problem, as it hinders both convincing justifications for this claim and the practical application of required protections. In this paper, I review consent-based, harm-based, and comprehensive definitions of vulnerability in healthcare and research with human subjects. Although current definitions are subject to critique, their underlying assumptions may be complementary. I propose that we should define vulnerability in research and healthcare as an identifiably increased likelihood of incurring additional or greater wrong. In order to identify the vulnerable, as well as the type of protection that they need, this definition requires that we start from the sorts of wrongs likely to occur and from identifiable increments in the likelihood, or to the likely degree, that these wrongs will occur. It is limited but appropriately so, as it only applies to special protection, not to any protection to which we have a valid claim. Using this definition would clarify that the normative force of claims for special protection does not rest with vulnerability itself, but with pre-existing claims when these are more likely to be denied. Such a clarification could help those who carry responsibility for the protection of vulnerable populations, such as Institutional Review Boards, to define the sort of protection required in a more targeted and effective manner.  相似文献   

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Brockman, II. E., and F. J. de Serres. (Oak Ridge Natl. Lab., Oak Ridge, Tenn.) “Sorbose toxicity” in Neurospora . Amer. Jour. Bot. 50(7): 709–714. Illus. 1963.—The effect of “sorbose toxicity” on Neurospora conidia or ascospores was compared in sorbose-fructose-glucose (S-F-G) and sorbose-sucrose (S-S) media. Many frequently encountered and difficultly controlled experimental variables may strongly affect viability in S-S media but are essentially without effect in S-F-G media. The viabilities of different mutant strains are affected to varying extents by autoclave exposure time of the S-S media but not of the S-F-G media. Ascospores are more sensitive than conidia to “sorbose kill” in S-S media. An over plating method described by New meyer (1954) for increasing ascospore “viability” is without effect when sucrose is replaced with fructose and glucose. In all experiments in which sorbose was added to induce colonial growth, “sorbose toxicity” or “sorbose kill” was eliminated or minimized by replacing sucrose with a mixture of fructose and glucose as the carbon source for Neurospora media.  相似文献   

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IntroductionThestudyofthemechanismofperistalticinbothmechanialandphysiologicalsituations,hasrecentlybecometheobjectofscientificresearch.SincethefirstinvestigationofLatham[1],severaltheoreticalandexperimentalattemptshavebeenmadetounderstandperistalticactionindifferentsituations.AreviewofmuchoftheearlyliteratureispresentedinanarticlebyJaffrinandShapiro[2].Asummaryofmostoftheexperimentalandtheoreticalinvestigationsreported,withdetailsofthegeometry,fluid,Reynoldsnumber,wavelengthparameter,waveam…  相似文献   

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The lymphoblastomas occurring in childhood are divided for purposes of discussion into lymphocytoma cutis, mycosis fungoides, lymphosarcoma, Hodgkin''s disease, and leukemia. The cutaneous lesions may be either specific (as a result of the infiltration of the skin with specific cells of the conditions) or toxic (non-specific). With the possible exception of mycosis fungoides, the cutaneous manifestations are not diagnostic. The final diagnosis depends upon microscopic examination of the specific tissue involved and the coordination of the clinical and microscopic findings.  相似文献   

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Physiological aspects of phosphate utilization by the blue-green alga Plectonema boryanum were studied. It was found that the external phosphate concentration influenced the distribution of phosphorus-containing compounds in the cell. Culturing the alga in concentrations of 10, 100, and 1000 mg PO4/l resulted in increases in the level of acid-soluble and acid-insoluble polyphosphates. The values reported for 100 and 1000 mg PO4/l were the same, indicating that the cells were able to assimilate and utilize only fixed amounts of phosphates. The total phosphorus value for these cells was calculated to be 6.5 μg P per 106 cells. Culturing the alga in 1 mg PO4/l led to a decrease in phosphate concentration of all cell fractions. Cells grown in the absence of phosphate for 5 days had total cell phosphorus levels of 0.76 μg P per 106 cells. Cells in culture for two months or longer were found to have total cell phosphorus levels of 0.73 μg P per 106 cells. This was determined to be the minimum cell phosphorus level limiting growth. Transfer of cells from either culture condition to a medium containing phosphate led to an “overplus” phenomenon. This overplus phenomenon was characterized by increases in all cellular phosphorus fractions. The most dramatic increase was found in both the acid-soluble and acid-insoluble polyphosphates. These fractions often increased by more than an order of magnitude. The greatest phosphate uptake occurred within 1 hr of transfer of phosphate-starved cells into a medium containing a known amount of phosphate and is essentially complete at 4 hr. The total cell phosphorus levels for uptake never increased beyond 18.9 μg per 106 cells.  相似文献   

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Periodogram analyses of the temporal variations of several cellular oscillations occasionally reveal the existence of short duration bands containing a wide range of frequencies. The possibility is considered that these are due to the transient compliance with chaotic conditions.  相似文献   

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Previous studies have shown that two or three lineages of Enallagma damselflies, which historically co-existed with fish, recently invaded and adapted to living with large dragonfly predators in fishless waters. In adapting to live with these new predators, lineages shifted behaviorally to using swimming as an evasive tactic against attacking predators, evolved morphological features that made them faster swimmers, and evolved biochemical features to increase refueling strenuous activities like swimming. However, these habitat shifts have occurred in only one of the two primary clades within the genus in North America. Here, I show that clade-level differences exist among species in the ancestral, fish-lake habitat that should make habitat shifts easier to accomplish in the clade in which they have occurred. Specifically, fish-lake species in the clade in which habitat shifts occurred have much higher propensities to swim in the laboratory, swim faster when they do swim, and have higher mass-specific activities for arginine kinase than do species in the other primary clade, in which no extant species are found in fishless waters. These results are discussed in the context of the dynamics of founder events and the potential implications for community structure.  相似文献   

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As a guide in distinguishing between organic and functional systolic murmurs, five characteristics of a murmur should always be noted, namely, (a) the location of maximal intensity of the murmur; (b) the intensity of the murmur itself; (c) the character of the murmur, that is, whether it is blowing, rumbling, rough or harsh; (d) the transmission of the murmur; and (e) the duration of the murmur and its time within the cardiac cycle.Functional systolic murmurs may be found at any of the “valve areas,” are usually faint to moderately loud, are usually soft and blowing in quality, are usually only slightly transmitted, and are usually not heard immediately following the first heart sound.In doubtful cases, those in which history and physical examination alone are not sufficient to make a diagnosis of functional systolic murmur, further studies should be undertaken to determine the presence or absence of organic heart disease.Until a diagnosis of organic heart disease can be made with reasonable certainty, there should be no restriction of activity imposed, because of the likelihood of the development of cardiac neurosis in the patient.  相似文献   

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This paper is dedicated as a token of homage and gratitude to Prof. Mu. En-zhi, the nestor in the field of graptolite studies, who introduced us chitinozoan studies with constant supports in many ways, and who died on 8th April, 1987. The Palaeontological Society of China has decided to publish a specieal volume in memory of this outstanding scientist.  相似文献   

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Science in China is a comprehensive academic journal of natural sciences sponsored by the Chinese Academy ofSciences. The primary purpose is to provide regulaf, rapid and authoritative reviews of current importantdevelopments in scientific research in China for scientific workers in China and other countries. The contents areselected by an extensive editorial committee which is composed of the most highly esteemed scientists in China  相似文献   

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~~SCIENCE IN CHINA(SCIENTIA SINICA)  相似文献   

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Science in China is a comprehensive academic journal of natural sciences sponsored by the Chinese Academy ofSciences. The primary purpose is to provide regular, rapid and authoritative reviews of current importantdevelopments in scientific research in China for scientific workers in China and other countries. The contents areselected by an extensive editorial committee which is composed of the most highly esteemed scientists in China  相似文献   

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RAMARIA SUBGENERA RAMARIA AND LAETICOLORA IN YUNNAN   总被引:1,自引:0,他引:1  
15.红柄丛枝瑚 Ramaria sanguinipes Petersen et Zang. Acta Bot. Yunnan 1986. 8: 289. Fruitbodies up to 6×5 cm, curved-obovate to generally circular in outline. Stipe up to 3×3 cm, single or fasciculate, stout, smooth to Somewhat marbled, off-white to ivory-colored, not canescent, often with aborted branchlets, rounded at base, tapering sharply downward, watery brunnescent, stained maroon ("Vandyke red," "madder red") at base, and suffused in this color upward; flesh solid, dry,  相似文献   

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