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Prevalent Problem (prevalent + problem)
Selected AbstractsReverse atom transfer radical polymerization of MMA via immobilized catalysts in imidazolium ionic liquidsJOURNAL OF APPLIED POLYMER SCIENCE, Issue 6 2007Najun Li Abstract Reverse atom transfer radical polymerization (RATRP) of methyl methacrylate (MMA) employing immobilized catalyst was approached at 50 and 60°C in [C8mim]PF6, and compared with the polymerization of MMA DMF as solvent. Other ionic liquids, [C6mim]BF4, [C8mim]BF4, and [C12mim]BF4, were used as solvents to perform the RATRP of MMA. By comparison, we found that the [C8mim]PF6 was the best solvent in this immobilized catalyst system and the polymerization was best controlled. In addition, the immobilized catalyst spherules can easily separate from the reaction mixture, which avoids the prevalent problem of the catalyst residual in RATRP and also gives us a possibility to recycle the catalyst system. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 3915,3919, 2007 [source] Chronic patients in undergraduate education: didactic value as perceived by studentsMEDICAL EDUCATION, Issue 8 2006Joseph P M Diederiks Objectives, Medical education should prepare students for future clinical practice. However, this preparation is inadequate for the most prevalent problem in health care: chronic disease. This applies to the continuous aspect of chronic disease. Within the context of a newly developed programme, we investigated what makes a chronic patient interesting in the eyes of medical students, what they learned from a specific programme in which each student had contact with a chronic patient 4 times in 8 months, and what they learned from their patients. Methods, A total of 240 Year 3 students were enrolled in the programme, 89 of whom filled in questionnaires at both the start and end of the programme. Topics included the characteristics of the ideal and the actual patient, the Ideal Physician Questionnaire, and several questions on the expected and actual amount of knowledge gained from the patient. Results, Students preferred patients who demonstrated clear symptoms and had frequent contacts with health care professionals during the programme to ,well adapted' patients. The perceived knowledge obtained from the patient was less than they had expected at the start of the programme. A didactic gain perceived as low was mainly due to low expectations of gaining knowledge at the start of the programme, a doctor-centred attitude and a high level of discrepancy between the student's ideal patient and the actual patient. Conclusions, Programmes that aim to present chronic patients to medical students focus on patient selection so that patients who differ only very slightly from healthy persons are eliminated. In addition, realistic information on the types of patients with whom students can expect to have contact may help students appreciate the knowledge to be gained from these patients. [source] Who Are the Potential Smokers of Smuggled Cigarettes?ASIAN ECONOMIC JOURNAL, Issue 3 2010Hsin-Fan Chen I18; C25 Although smuggled cigarettes have been a prevalent problem and a severe challenge to public health and welfare around the world, little is known about the behavior associated with smoking smuggled cigarettes and the issue is difficult to study due to data limitations. By means of a population-based tobacco survey conducted in Taiwan, the present paper applies a latent class model to identify potential smokers who are either currently or will at some point in the future be consuming smuggled cigarettes. This methodology, in contrast to the traditional discrete models, allows potential smokers who are more inclined to smoke smuggled cigarettes to be endogenously classified. The empirical results indicate that socio-demographic factors do increase the inclination to smoke smuggled cigarettes after unobserved heterogeneity has been accounted for. [source] Lifestyle factors in people seeking infertility treatment , A reviewAUSTRALIAN AND NEW ZEALAND JOURNAL OF OBSTETRICS AND GYNAECOLOGY, Issue 1 2010Kirsty ANDERSON Background:, Clinical infertility is a prevalent problem with significant financial and psychosocial costs. Modifiable lifestyle factors exist that may affect a person's time to conception and their chance of having a healthy, live birth. However, no guideline delineates what preconception advice should be offered to people presenting for infertility treatment. Aim:, The aim of this article is to review the literature regarding modifiable lifestyle factors in people seeking infertility treatment. Results:, A person's time to pregnancy and their chance of having a healthy, live birth may be affected by factors such as weight, vitamin and iodine intake, alcohol and caffeine consumption, smoking, substance abuse, stress, environmental pollutants, vaccinations and oxidative stress. Conclusions:, Advice on modifiable lifestyle factors should be given to people presenting for infertility treatment to help them make positive changes that may improve their chances of pregnancy and delivering a healthy, live baby. Developing a guideline for this would be a prudent step towards helping clinicians to implement this aspect of preconception care. [source] Erosive potential of beverages sold in Australian schoolsAUSTRALIAN DENTAL JOURNAL, Issue 3 2009NJ Cochrane Abstract Background:, Dental erosion is an increasingly prevalent problem in Australia. The aim of this study was to analyse the composition and erosive potential of beverages sold for consumption in Victorian schools. Methods:, Fifteen drinks were selected and analysed to determine their pH, titratable acidity and ionic composition (calcium, fluoride and inorganic phosphate). The erosive potential of the beverages was measured by analysing weight loss, surface loss and the release of calcium ions from human enamel following a 30-minute or 24-hour exposure. The association of the chemical parameters with the measures of erosion was determined using Spearman's rank correlation. Results:, All beverages tested except the milks and the bottled water produced significant dental erosion in vitro. The only chemical parameter that correlated significantly with all measures of erosion was the initial pH of the beverage (p < 0.01). Levels of fluoride similar to those of Australian reticulated water were found in the carbonated beverages. Conclusions:, The majority of the tested beverages sold from school canteens exhibited erosive potential. [source] Novel Hemoglobins to Enhance Microaerobic Growth and Substrate Utilization in Escherichiacoli,BIOTECHNOLOGY PROGRESS, Issue 5 2001Christian J. T. Bollinger Limited oxygen availability is a prevalent problem in microbial biotechnology. Recombinant Escherichia coli expressing the hemoglobin from Vitreoscilla (VHb) or the flavohemoglobin from Ralstonia eutropha (formerly Alcaligenes eutrophus) (FHP) demonstrate significantly increased cell growth and productivity under microaerobic conditions. We identify novel bacterial hemoglobin-like proteins and examine if these novel bacterial hemoglobins can elicit positive effects similar to VHb and FHP and if these hemoglobins alleviate oxygen limitation under microaerobic conditions when expressed in E. coli. Several finished and unfinished bacterial genomes were screened using R. eutropha FHP as a query sequence for genes (hmp) encoding hemoglobin-like proteins. Novel hmp genes were identified in Pseudomonas aeruginosa, Salmonella typhi, Klebsiellapneumoniae, Deinococcus radiodurans, and Campylobacter jejuni. Previously characterized hmp genes from E. coli and Bacillus subtilis and the novel hmpgenes from P. aeruginosa, S. typhi, C. jejuni, K.pneumoniae, and D. radiodurans were PCR amplified and introduced into a plasmid for expression in E. coli. Biochemically active hemoproteins were expressed in all constructs, as judged by the ability to abduct carbon monoxide. Growth behavior and byproduct formation of E. coli K-12 MG1655 cells expressing various hemoglobins were analyzed in microaerobic fed-batch cultivations and compared to plasmid-bearing control and to E. coli cells expressing VHb. The clones expressing hemoglobins from E. coli, D. radiodurans, P.aeruginosa, and S. typhi reached approximately 10%, 27%, 23%, and 36% higher final optical density values, respectively, relative to the plasmid bearing E. coli control (A600 5.5). E. coli cells expressing hemoproteins from P. aeruginosa, S. typhi, and D. radiodurans grew to similar final cell densities as did the strain expressing VHb (A600 7.5), although none of the novel constructs was able to outgrow the VHb-expressing E. coli strain. Additionally, increased yield of biomass on glucose was measured for all recombinant strains, and an approximately 2-fold yield enhancement was obtained with D.radiodurans hemoprotein-expressing E. colirelative to the E. coli control carrying the parental plasmid without any hemoglobin gene. [source] Brain regulation of food intake and appetite: molecules and networksJOURNAL OF INTERNAL MEDICINE, Issue 4 2005C. BROBERGER Abstract. In the clinic, obesity and anorexia constitute prevalent problems whose manifestations are encountered in virtually every field of medicine. However, as the command centre for regulating food intake and energy metabolism is located in the brain, the basic neuroscientist sees in the same disorders malfunctions of a model network for how integration of diverse sensory inputs leads to a coordinated behavioural, endocrine and autonomic response. The two approaches are not mutually exclusive; rather, much can be gained by combining both perspectives to understand the pathophysiology of over- and underweight. The present review summarizes recent advances in this field including the characterization of peripheral metabolic signals to the brain such as leptin, insulin, peptide YY, ghrelin and lipid mediators as well as the vagus nerve; signalling of the metabolic sensors in the brainstem and hypothalamus via, e.g. neuropeptide Y and melanocortin peptides; integration and coordination of brain-mediated responses to nutritional challenges; the organization of food intake in simple model organisms; the mechanisms underlying food reward and processing of the sensory and metabolic properties of food in the cerebral cortex; and the development of the central metabolic system, as well as its pathological regulation in cancer and infections. Finally, recent findings on the genetics of human obesity are summarized, as well as the potential for novel treatments of body weight disorders. [source] | ||||||||||