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We present a framework within which to evaluate and compare computational methods to solve elliptic partial differential equations. We then report on the results of comparisons of some classical methods as well as a new one presented here. Our main motivation is the belief that the standard finite difference methods are almost always inferior for solving elliptic problems and our results are strong evidence that this is true. The superior methods are higher order (fourth or more instead of second) and we describe a new collocation finite element method which we believe is more efficient and flexible than the other well known methods, e.g., fourth order finite differences, fourth order finite element methods of Galerkin, Rayleigh-Ritz or least squares type. Our comparisons are in the context of the relatively complicated problems that arise in realistic applications. Our conclusion does not hold for simple model problems (e.g., Laplaces equation on a rectangle) where very specialized methods are superior to the generally applicable methods that we consider. The accurate and relatively simple treatment of boundary conditions involving curves and derivations is a feature of our collocation method.

Background: C-reactive protein (CRP) is associated with risk of coronary heart disease (CHD). Whether CRP is causally associated with CHD or merely a marker of underlying atherosclerosis is uncerta...

This cross-sectional study investigated the prevalence and correlates of lower-extremity amputation (LEA) in a Saudi population with diabetic foot ulcer. The study population consisted of 91 participants, with a median age of 55.0 years. Biomarkers were measured following standard protocols. Local symptoms of foot ulcer, including peripheral neuropathy (PN), peripheral artery disease (PAD), and foot infection were diagnosed by standard objective diagnostic tools or diagnosed clinically by a specialized surgeon. The severity of foot ulcer was classified according to the Wagner wound classification system. The prevalence of LEA was 29.7% in this population. The odds ratio for LEA comparing extreme tertiles was 2.42 (95% confidence interval [CI] = 0.70-8.45; P for trend = .03) for ulcer size and 0.22 (95% CI = 0.06-0.87; P for trend = .03) for high-density lipoprotein cholesterol. C-reactive protein and homocysteine levels were each positively associated with odds of LEA, but the associations became nonsignificant in multivariable models. Participants with foot infection showed a significantly higher adjusted prevalence of LEA (40.7%, 95% CI = 27.1%-54.3%) compared with those without foot infections (19.3%, 95% CI = 6.0%-32.4%, P = .03). Participants with Wagner grade ≥3 presented a significantly higher prevalence (40.5%, 95% CI = 27.8%-53.2%) than those with Wagner grade of 1 or 2 (16.4%, 95% CI = 2.4%-30.5%, P = .02). Participants with PN and PAD showed nonsignificantly higher prevalence of LEA. We found a relatively high prevalence of LEA as well as several clinical markers and local symptoms associated with LEA in this Saudi population with diabetic foot ulcer.

Epidemiologic evidence for the role of glycemic index (GI) and glycemic load (GL) in the prevention of type 2 diabetes (T2D) has been mixed. The American Diabetes Association’s nutrition recommendations for T2D prevention state that there is not sufficient, consistent evidence to conclude that low GL diets reduce T2D risk but acknowledge the role of low GI foods rich in fiber in preventing T2D. Therefore, our objectives were to 1) prospectively examine the association of dietary GI and GL with T2D in 3 US cohorts, and 2) conduct an updated meta-analysis of the previous literature including results from our 3 cohorts. We prospectively followed 74,248 women from the Nurses’ Health Study (1984-2008), 86,484 women from the Nurses’ Health Study II (1991-2009), and 40,525 men from the Health Professionals Follow-up Study (1986-2008) who were free of diabetes, cardiovascular disease, and cancer at baseline. Diet was assessed every 4 years using a validated questionnaire. During 3,738,507 person-years of follow-up, we documented 14,482 T2D cases. In pooled multivariable analyses, after adjusting for dietary and non-dietary covariates including body mass index, those in the highest quintile of energy-adjusted GI had a 34% higher risk (95% CI: 27-43%) of T2D. Participants in the highest quintile of energy-adjusted GL had a 13% higher risk (95% CI: 5-22%) for T2D. Participants in the highest tertile of GI/GL and lowest tertile of cereal fiber had about a 50% (GI, RR=1.59, 95% CI:1.47-1.73; GL, RR=1.47, 95% CI:1.32-1.63) higher risk for T2D compared to those in the lowest tertile of GI/GL and highest tertile of cereal fiber. In the updated meta-analysis (675,767 participants and 45,570 T2D cases), the summary RRs (95% CIs) comparing the highest versus lowest categories of GI and GL were 1.19 (1.15-1.24) and 1.13 (1.09-1.18), respectively (Figure 1A and 1B). Our findings provide further evidence that a high GI/GL diet is associated with a higher T2D risk. Public health recommendations for T2D prevention should incorporate GI and GL in meal planning.

n- and p-type Ge nanowires were synthesized by a multistep process in which axial elongation, via vapor–liquid–solid (VLS) growth, and doping were accomplished in separate chemical vapor deposition steps. Intrinsic, single-crystal, Ge nanowires prepared by Au nanocluster-mediated VLS growth were surface-doped in situ using diborane or phosphine, and then radial growth of an epitaxial Ge shell was used to cap the dopant layer. Field-effect transistors prepared from these Ge nanowires exhibited on currents and transconductances up to 850 μA/μm and 4.9 μA/V, respectively, with device yields of >85%.

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Objective Associations of overall and regional body fat measured by dual‐energy X‐ray absorptiometry with total and cause‐specific mortality in the National Health and Nutrition Examination Survey (NHANES) 1999‐2006 were investigated. Methods This study included 9,471 participants (≥20 years) free of major chronic diseases at baseline. Death information was obtained from the National Death Index (mean follow‐up duration: 8.8 years). Results A total of 682 participants died after 12 months since baseline, with 206 and 170 deaths attributed to cardiovascular diseases (CVD) and cancer, respectively. The second quartile of fat mass percentages (FM%) was used as the reference to account for potential nonlinearity. In the multivariate‐adjusted model, participants in the highest quartile of total FM% had increased total mortality; hazard ratio (HR; 95% confidence interval, 95% CI) was 1.48 (1.07‐2.04; P < 0.05). Higher total and trunk FM%, but not leg FM%, were significantly associated with an increased CVD mortality; HRs (95% CIs) in the highest quartiles of total, trunk, and leg FM% were 2.24 (1.17‐4.31), 1.93 (1.02‐3.66), and 1.50 (0.77‐2.94), respectively. Conclusions Higher total body fat was associated with increased total mortality in U.S. adults. Higher total and trunk fat contents were also associated with increased CVD mortality, although fat accumulation in the lower body was not an independent predictor of mortality.

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTChemical modification of acrylamide gels: verification of the role of ionization in phase transitionsDavid Nicoli, Carl Young, Toyoichi Tanaka, Alfred Pollak, and George WhitesidesCite this: Macromolecules 1983, 16, 6, 887–890Publication Date (Print):June 1, 1983Publication History Published online1 May 2002Published inissue 1 June 1983https://pubs.acs.org/doi/10.1021/ma00240a011https://doi.org/10.1021/ma00240a011research-articleACS PublicationsRequest reuse permissionsArticle Views209Altmetric-Citations35LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InRedditEmail Other access optionsGet e-Alertsclose Get e-Alerts

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Several clinical studies suggest the involvement of premature ageing processes in chronic obstructive pulmonary disease (COPD). Using an epidemiological approach, we studied whether accelerated ageing indicated by telomere length, a marker of biological age, is associated with COPD and asthma, and whether intrinsic age-related processes contribute to the interindividual variability of lung function. Our meta-analysis of 14 studies included 934 COPD cases with 15 846 controls defined according to the Global Lungs Initiative (GLI) criteria (or 1189 COPD cases according to the Global Initiative for Chronic Obstructive Lung Disease (GOLD) criteria), 2834 asthma cases with 28 195 controls, and spirometric parameters (forced expiratory volume in 1 s (FEV1), forced vital capacity (FVC) and FEV1/FVC) of 12 595 individuals. Associations with telomere length were tested by linear regression, adjusting for age, sex and smoking status. We observed negative associations between telomere length and asthma (β= -0.0452, p=0.024) as well as COPD (β= -0.0982, p=0.001), with associations being stronger and more significant when using GLI criteria than those of GOLD. In both diseases, effects were stronger in females than males. The investigation of spirometric indices showed positive associations between telomere length and FEV1 (p=1.07×10(-7)), FVC (p=2.07×10(-5)), and FEV1/FVC (p=5.27×10(-3)). The effect was somewhat weaker in apparently healthy subjects than in COPD or asthma patients. Our results provide indirect evidence for the hypothesis that cellular senescence may contribute to the pathogenesis of COPD and asthma, and that lung function may reflect biological ageing primarily due to intrinsic processes, which are likely to be aggravated in lung diseases.