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71.
A role for GH in the pathogenesis of diabetic retinopathy has long been postulated. Previous clinical studies, however, have been confounded by hyperglycemia. We have identified 2 cases of retinopathy associated with exogenous GH therapy in nondiabetic patients. Cases were identified through the MedWatch drug surveillance system of the U.S. Food and Drug Administration. Causality by concomitant medications was excluded by a search of the literature and the FDA data base. The first patient, an obese, 31-yr-old male with traumatic hypothalamic injury, presented with nonproliferative retinopathy and macular edema, resulting in decreased visual acuity (OD 20/40-1; OS count fingers), which required laser surgery. Human GH had been initiated at 0.009 mg/ kg.day, 14 months earlier, and titrated to 0.017 mg/kg.day. The second patient, a nonobese, 11-yr-old girl receiving GH for the management of short stature in Turner's Syndrome, presented with neovascularization. GH doses were 0.033 mg/kg.day for the first 17 months and 0.043 mg/ kg.day for the following 5 months. Cumulative laboratory and clinical observations suggest that GH and related peptides have a role in retinal pathology independent of the degree of glucose tolerance.  相似文献   
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The minterms of the switching function expressed as decimal numbers are first partitioned into different groups according to the number of true inputs. An order of the weights and their signs can now be found easily. Secondary and higher orderings can also be found partially. An iteration procedure is next started by assigning values to the weights until a contradiction is reached. A new assignment is then chosen, guided by the nature of the contradiction, and this process is continued until the realisation is achieved. An example is worked out.  相似文献   
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Seven hundred and thirty-two cases of appendicectomy performed over a period of 5 years are reviewed to compare the incidence of complications and the length of the postoperative stay in hospital, depending on whether the appendix stump was simply ligated or was invaginated by purse string suture following ligation. No detrimental effects are noted following simple ligation, whereas patients who had stump invagination remained in hospital on average more than a day longer, mainly owing to a higher incidence of wound infection (16 per cent as against 6 per cent).  相似文献   
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We report here an experience with five patients, aged 58 to 70, suffering gangrene of the left colon after spontaneous inferior mesenteric artery occlusion. All cases were the result of arteriosclerosis; in two, small aortic aneurysms were present and might have been responsible for emboli to the inferior mesenteric artery. The dead bowel was resected in all patients; three patients survived. No primary anastomoses were done and they are not recommended. Because ligation of the patent inferior mesenteric artery has been done so often without ill effects during aortic surgery, the collateral circulation to the left colon can be considered excellent. Gangrene is therefore rare and requires major interference with collateral circulation by emboli or arteriosclerotic occlusion. The clinical symptoms and signs may be confusing.  相似文献   
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Sinha A  Barbastathis G 《Applied optics》2004,43(31):5784-5795
Volume holographic imaging utilizes Bragg selectivity to optically slice the object space of the imaging system and measure four- (three spatial and one spectral) dimensional object information. The N-ocular version of this method combines multiple-volume holographic sensors and digital postprocessing to yield high-resolution three-dimensional images for broadband objects located at long working distances. We discuss the physical properties of volume holography pertinent to imaging performance and describe two computational algorithms for image inversion based on filtered backprojection and least-squares optimization.  相似文献   
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A bioinert ceramic substrate, α-Al2O3, has been coated with hydroxyapatite (HAp) by the biomimetic route using simulated body fluid (SBF) solution at room temperature. The substrate was incubated at 37°C in SBF for 6 days with a periodic replacement with freshly prepared SBF at 48-h intervals. After 6 days, continuous nanofiber-like structures of HAp (5–35 μm in length, 0.05 μm diameter) were obtained, connecting the intra- and interglobular clusters, within the coated mineral layer on the substrate surface. This is a unique and new observation, and this phenomenon has been demonstrated by a simple fractal growth model.  相似文献   
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