A 32-year-old woman was admitted with signs of recurrent hypoglycaemia. Within 72 hours hypoglycaemia was successfully provoked by prolonged fasting. Also, blood samples demonstrated high levels of serum insulin and C-peptide and the insulin-glucose ratio was abnormally high. An insulinoma was strongly suspected. However, extensive imaging displayed no tumour in the pancreas. The patient also had extensive psychological and social problems. The psychiatrist suggested a factitious disorder. High serum concentrations of insulin and C-peptide in combination with the psychiatric disorder led to the suspicion of abuse of sulfonylurea derivatives by the patient. This was confirmed by toxicological screening. A patient with unexplained hypoglycaemia, especially if an insulinoma cannot be detected, should be suspected of abusing sulfonylurea derivatives. 相似文献
Strictureplasty for treatment of symptomatic intestinal strictures secondary to Crohn's disease is being performed with increasing frequency. To determine the overall clinical results after strictureplasty for Crohn's disease, all patients undergoing this procedure were prospectively studied. Between 6/1/89 and 2/1/97, 57 Crohn's disease patients underwent 60 operations utilizing strictureplasties. A total of 109 strictureplasties were performed (90 Heineke-Mikulicz, 6 Finney, and 13 side-to-side isoperistaltic). The 30-day perioperative morbidity was 12%, with complications being less common for patients undergoing elective versus unscheduled operations (p < 0.002). Recurrence of Crohn's disease requiring operation was seen in seven patients after a mean follow-up of 38 months. The estimated cumulative recurrence rate after 2 years was 15 +/- 6% (+/- standard error) and 22 +/- 10% at 5 years. A recurrence developed at the site of the previous strictureplasty in only five cases. Strictureplasty is a safe, effective means of providing long-term surgical palliation to selected patients with Crohn's disease. Perioperative complication rates are comparable to those seen with standard surgical treatment, and recurrences are not excessive. 相似文献
A leading-edge 90-nm technology with 1.2-nm physical gate oxide, 45-nm gate length, strained silicon, NiSi, seven layers of Cu interconnects, and low-/spl kappa/ CDO for high-performance dense logic is presented. Strained silicon is used to increase saturated n-type and p-type metal-oxide-semiconductor field-effect transistors (MOSFETs) drive currents by 10% and 25%, respectively. Using selective epitaxial Si/sub 1-x/Ge/sub x/ in the source and drain regions, longitudinal uniaxial compressive stress is introduced into the p-type MOSEFT to increase hole mobility by >50%. A tensile silicon nitride-capping layer is used to introduce tensile strain into the n-type MOSFET and enhance electron mobility by 20%. Unlike all past strained-Si work, the hole mobility enhancement in this paper is present at large vertical electric fields in nanoscale transistors making this strain technique useful for advanced logic technologies. Furthermore, using piezoresistance coefficients it is shown that significantly less strain (/spl sim/5 /spl times/) is needed for a given PMOS mobility enhancement when applied via longitudinal uniaxial compression versus in-plane biaxial tension using the conventional Si/sub 1-x/Ge/sub x/ substrate approach. 相似文献
Waterborne (WB) products are of growing importance in the car refinishes market. Especially WB basecoats are gaining increased market share during the last couple of years. The introduction of WB two-pack primers, fillers, clearcoats and single stage topcoats is hampered, however due to the lack of suited binder systems.
In this paper, new approaches will be presented for two-pack binder systems. A number of topics will be discussed in more detail: the design of the binders, the involved chemistry, the incorporation of stabilizing and reactive groups, the functionality and miscibility of the hardener. Based on these variables, the most important properties have been studied: film formation, reactivity, potlife and paint properties like hardness, appearance and water and solvent resistance. During the investigation, model studies have also been applied.
It is shown that some binder systems offer very attractive features in which a number of properties can be tuned, e.g. amine-functional emulsions combined with acetoacetate-functional hardeners result in an excellent level of properties suited for primer/filler application.
These binder systems have been used as the starting points for product development that resulted in new prototypes of low VOC WB products with a very attractive overall performance. 相似文献
The authors present the historical analysis of one of the central questions in psychology: how and why the nonautomatic, psychological level of regulation (in contrast to automatic physiological processes) emerges both in evolution and in everyday context of activity. They discuss several approaches (by Lipps, Groos, Stern, James, Dewey, Claparede, Pavlov, and Leontiev) that culminated in the system of ideas developed by Galperin, one of the key figures in the cultural-historical activity theory. The authors analyze the relation of Galperin's ideas to Vygotsky's theoretical framework and then focus on Galperin's account of the origin and functions of mental activity. Galperin's contribution is highly relevant for understanding the role of psychological regulation and for contemporary research on cognition, consciousness, and conscious awareness. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
Nanocrystalline ceria has been synthesized by a non-hydrolytic method using organic solvent and precipitant. The effect of the source compound on final nanocrystalline powder was investigated. The cerium nitrate hexahydrate subjected to different vacuum/thermal treatments to get cerium source compound having different extent of water of crystallization. The nanoceria, synthesized from these compounds was characterized by TGA-MS, XRD, HR-TEM and AFM. 相似文献
Several investigators have recently reported that significant numbers of appropriately adapted mutants can be induced in bacterial and yeast strains by exposing stationary phase cells to specific environmental challenges. The resulting mutants are said to be both selection-induced and demonstrably non-random in origin; if this interpretation is correct, it is in direct conflict with the conventional neo-Darwinian view, which is that spontaneous mutants are truly random in origin and arise without the intervention of any overtly adaptive forces. We believe that there are alternative ways of accounting for the appearance of many (and probably all) of the additional mutants which proponents of the adaptive mutation theory claim are observed only after they applied the appropriate selective pressure. Having reviewed the available evidence, we consider that most (if not all) of the sorts of mutants which are said to have been induced following exposure of stationary-phase cells to intense selective pressure are equally likely to have been generated during the operation of certain well-known, conventional (and essentially random) cellular DNA repair processes. Evidence in support of our view can be found in the mainstream literature on the origins of spontaneous mutations. We also note that some of the molecular models which have recently been proposed to explain the production of selection-induced mutations preferentially (or even only) in genes of adaptive significance may turn out to be of considerable interest in their own right, even although the mutants whose origins they were intended to explain may turn out to have arisen in a manner which is totally independent of the conditions used for their selection. 相似文献