Diabetic Peripheral Neuropathy in Type 2 Diabetes Mellitus in Korea

Diabetic peripheral neuropathy (DPN), a common and troublesome complication in patients with type 2 diabetes mellitus (T2DM), contributes to a higher risk of diabetic foot ulcer and lower limb amputation. These situations can negatively impact the quality of life of affected individuals. Despite its high prevalence and clinical importance, most diabetes mellitus patients not only do not recognize the presence of diabetic neuropathy, but also do not report their symptoms to physicians or other health care providers. Therefore, DPN is usually under diagnosed and undertreated. For early detection and appropriate intervention for DPN, a careful history, physical with neurologic examination, and prompt treatment are needed in T2DM patients

A review of non-destructive testing techniques for the in-situ investigation of fretting fatigue cracks

© 2020 The Authors Fretting fatigue can significantly reduce the life of components, leading to unexpected in-service failures. This phenomenon has been studied for over a century, with significant progress being made during the past decade. There are various methods that have been used to study fretting fatigue cracks in order to gain a greater understanding of the effects of fretting fatigue. Destructive methods are traditionally used to observe fretting fatigue cracks. Although useful in determining crack location, crack length, crack propagation modes, crack path and shape, it is not efficient or reliable for time based measurements. Non-destructive testing has developed in recent years and now in-situ monitoring can be used during testing in order to increase the understanding of fretting fatigue. This paper presents a review of non-destructive testing techniques used in-situ during fretting fatigue testing, which are compared in order to conclude the suitability of each technique. Recent developments in non-destructive techniques that could be also applied for fretting fatigue tests are also discussed, as well as recommendations for future research made

Cocaine Is Low on the Value Ladder of Rats: Possible Evidence for Resilience to Addiction

International audienceBACKGROUND:Assessing the relative value of cocaine and how it changes with chronic drug use represents a long-standing goal in addiction research. Surprisingly, recent experiments in rats--by far the most frequently used animal model in this field--suggest that the value of cocaine is lower than previously thought.METHODOLOGY/PRINCIPAL FINDINGS:Here we report a series of choice experiments that better define the relative position of cocaine on the value ladder of rats (i.e., preference rank-ordering of different rewards). Rats were allowed to choose either taking cocaine or drinking water sweetened with saccharin--a nondrug alternative that is not biologically essential. By systematically varying the cost and concentration of sweet water, we found that cocaine is low on the value ladder of the large majority of rats, near the lowest concentrations of sweet water. In addition, a retrospective analysis of all experiments over the past 5 years revealed that no matter how heavy was past cocaine use most rats readily give up cocaine use in favor of the nondrug alternative. Only a minority, fewer than 15% at the heaviest level of past cocaine use, continued to take cocaine, even when hungry and offered a natural sugar that could relieve their need of calories.CONCLUSIONS/SIGNIFICANCE:This pattern of results (cocaine abstinence in most rats; cocaine preference in few rats) maps well onto the epidemiology of human cocaine addiction and suggests that only a minority of rats would be vulnerable to cocaine addiction while the large majority would be resilient despite extensive drug use. Resilience to drug addiction has long been suspected in humans but could not be firmly established, mostly because it is difficult to control retrospectively for differences in drug self-exposure and/or availability in human drug users. This conclusion has important implications for preclinical research on the neurobiology of cocaine addiction and for future medication development

Acylation of alcohols and activated aromatic compounds on silica embedded-triflate catalysts

A series of triflate derivatives (La(OTf)(3), tert-butyl-dimethyl-silyltrifluoromethane-sulfonate (BDMST) and triflic acid (HOTf)) embedded in a silica matrix were Used as heterogeneous catalysts for the acylation of alcohols and activated aromatic Compounds. Acylation of saturated alcohols and cyclohexanol resulted in O-acylated products. The acylation of the aromatic compounds was dependent on temperature and substituents. At low temperatures, for phenols and naphtols, acylation occurred mainly to O-acylated. Under these conditions, the presence of catalysts only enhanced the reaction rate. The increase of the temperature above 150 degrees C also led to C-acylation. For anisole and 1-methoxynaphtalene, acylation occurred at the aromatic ring even at low temperatures. (c) 2005 Elsevier B.V. All rights reserved

Alkylation of hydroquinone with tert-butanol over silica-immobilized triflate derivatives

Silica immobilized La(OTf)(3), tertbutyldimethylsilyl-triflate and triflic acid proved to be very efficient catalysts for the hydroquinone alkylation with tert-butanol. In solvent free conditons, the conversion was higher than 95% with the dialkylated product (2,5-DTBHQ) formed in high yields. When a polar solvent (1,4-dioxane) was used, the selectivity towards the monoalkylated product (2-TBHQ) increased up to 90%

Silica-embedded tert-butyldimethylsilyltrifluoromethanesulfonate catalysts as new solid acid catalysts

Silica-embedded tert-butyldimethylsilyltrifluoromethanesulfonate catalysts were synthesized by a sol-gel method in acidified CCl4, using hexadecyltrimethyl-ammonium bromide as a surfactant. The catalysts were characterized by nitrogen adsorption-desorption isotherms at 77 K; TG-DTA; H-1, C-13, and Si-29 solid state MAS/NMR; XRD; XPS; Raman spectroscopy; and FTIR after adsorption of NH3. The characterization data indicated mesoporous solids in which most of the silyl-triflate derivative keeps its integrity. The catalytic tests performed with the methyl ester of 1-cyclopentenylacetic acid in various solvents showed that the reaction selectively leads to 3-methylbenzaldehyde and is sensitive to the solvent accepting ability. (C) 2001 Academic Press