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61.
A recent survey at Clarkson University showed that students consider technical communication the least worthy and the least difficult of the institution's majors. This prejudice is attributed to the student's high regard for technology and its quantitative, problem-solving analysis coupled with conversely low regard for writing. The author describes his experience with the misconceptions and how he came to understand that technical communication is not a contradiction in terms 相似文献
62.
J.L. Campbell B.M. Millman J.A. Maxwell A. Perujo W.J. Teesdale 《Nuclear instruments & methods in physics research. Section B, Beam interactions with materials and atoms》1985,9(1):71-79
Monoenergetic X-ray lines produced by diffraction from a curved crystal monochromator have been used to test the applicability of the Hypermet function for Si(Li) detectors. Excellent fits are achieved; the function's parameters vary smoothly with energy, and the intensity of the non-Gaussian peak components correlates with the thickness of the frontal dead layer where charge collection is incomplete. Accurate silicon escape peak intensities are presented and the contribution to the lineshape from Compton-scattered events is discussed qualitatively. 相似文献
63.
Role of HIF-1alpha in hypoxia-mediated apoptosis, cell proliferation and tumour angiogenesis 总被引:1,自引:0,他引:1
P Carmeliet Y Dor JM Herbert D Fukumura K Brusselmans M Dewerchin M Neeman F Bono R Abramovitch P Maxwell CJ Koch P Ratcliffe L Moons RK Jain D Collen E Keshert E Keshet 《Canadian Metallurgical Quarterly》1998,394(6692):485-490
As a result of deprivation of oxygen (hypoxia) and nutrients, the growth and viability of cells is reduced. Hypoxia-inducible factor (HIF)-1alpha helps to restore oxygen homeostasis by inducing glycolysis, erythropoiesis and angiogenesis. Here we show that hypoxia and hypoglycaemia reduce proliferation and increase apoptosis in wild-type (HIF-1alpha+/+) embryonic stem (ES) cells, but not in ES cells with inactivated HIF-1alpha genes (HIF-1alpha-/-); however, a deficiency of HIF-1alpha does not affect apoptosis induced by cytokines. We find that hypoxia/hypoglycaemia-regulated genes involved in controlling the cell cycle are either HIF-1alpha-dependent (those encoding the proteins p53, p21, Bcl-2) or HIF-1alpha-independent (p27, GADD153), suggesting that there are at least two different adaptive responses to being deprived of oxygen and nutrients. Loss of HIF-1alpha reduces hypoxia-induced expression of vascular endothelial growth factor, prevents formation of large vessels in ES-derived tumours, and impairs vascular function, resulting in hypoxic microenvironments within the tumour mass. However, growth of HIF-1alpha tumours was not retarded but was accelerated, owing to decreased hypoxia-induced apoptosis and increased stress-induced proliferation. As hypoxic stress contributes to many (patho)biological disorders, this new role for HIF-1alpha in hypoxic control of cell growth and death may be of general pathophysiological importance. 相似文献
64.
Parallel monthly surveys of children aged 6-71 months were conducted in the Muheza district of Tanzania. The aim was to compare highland villages, where the mean, annual entomological inoculation rate (EIR) for malaria is 34 and mean annual prevalences of parasitaemia range from 33%-76%, with culturally similar villages of the lowlands, where the mean EIR is 405 and prevalences of parasitaemia range from 80%-84%. The total survey population could be divided into six geographical subgroups, which can be arranged in order of increasing prevalence of parasitaemia. The prevalences of dense parasitaemia, of febrile malaria, and of anaemia all increased in the same order across this series of groups, the trends being statistically significant. The results of previous studies have indicated a paradoxical effect whereby children in regions with a lower exposure to malarial infection suffer, in the long term, a higher incidence of severe attacks of malaria. In the present study there was no sign of any such paradoxical inverse relationship between the level of exposure and the prevalence of malarial illness or anaemia. However, child mortality rates are similar in the highlands and lowlands, as are the median ages of children admitted to hospital. Overall, the present findings indicate that, for the populations studied, an artificial reduction in EIR would be beneficial, even in the long term, with regard to the chronic effects of malaria. This does not necessarily conflict with previous studies reporting opposite conclusions with regard to the incidence of severe,acute effects. 相似文献
65.
66.
I Rajman GY Lip R Cramb SR Maxwell J Zarifis DG Beevers MJ Kendall 《Canadian Metallurgical Quarterly》1996,89(10):771-778
In a prospective longitudinal study in 17 women, we investigated the effects of surgical menopause and subsequent oestrogen-only hormone replacement therapy (HRT) on plasma concentrations of total cholesterol, HDL cholesterol, LDL cholesterol, triglyceride and LDL subfractions profile. Plasma LDL is a heterogeneous population of particles of varying size, density and chemical composition. The predominance of small LDL particles is a newly-recognized risk factor for coronary artery disease. The LDL score is used to describe LDL subfractions profile and the greater the score, the higher the proportion of small LDL particles. Six weeks after hysterectomy and bilateral oopherectomy, total cholesterol and triglyceride concentrations were significantly increased (p < 0.01) as well as the LDL score (p < 0.05). After 6 weeks of oestrogen-only HRT, total cholesterol concentration was significantly lower and HDL cholesterol concentration significantly higher than before the treatment (p < 0.05). At the same time, mean LDL score significantly increased and in none of the women did LDL subfractions profile change favourably. 相似文献
67.
An experimental investigation of the dynamic mechanical response of molten polymers was performed using the Maxwell Orthogonal Reheometer. One purpose of the study was to evaluate the effect of molecular weight distribution on the temperature dependence of viscoelastic properties. Data were obtained over a range of temperatures for both monodisperse and polydisperse materials which indicate that viscoelasticity is highly temperature dependent only for monodisperse polymers. On a molecular basis the reduction in temperature sensitivity for polydisperse materials logically can be attributed to the influence of the low molecular weight species present in a distribution on the relaxation spectrum. Since the relaxation spectrum largely determines all viscoelastic functions, the observations made from th dynamic data shown in this paper can be generalized to all viscoelastic experiments. 相似文献
68.
A 27 month old child presented with left hemiplegia and was found to have deep cerebral venous thrombosis. The deep cerebral venous thrombosis resolved on warfarin. Elevated and fluctuating anticardiolipin antibodies as well as protein S deficiency were detected. 相似文献
69.
A patient with the anti-phospholipid antibody syndrome and digital clubbing is described. No recognized cause for the clubbing was found. It is suggested that platelet aggregation and microthrombi formation as a result of anti-phospholipid antibody may be involved in the pathogenesis of the digital clubbing. This may be a new feature of the anti-phospholipid antibody. 相似文献
70.
Flexible monitoring helped to establish an intermediate care unit, close an intensive care unit (ICU) and reduce cost by decreasing length of stay (LOS) and matching patients to appropriate care. These efforts saved the hospital $3,260,215 over the first year while maintaining positive patient outcomes. 相似文献