Free volume dilatation in polymers by ortho-positronium

The possibility of positronium induced free volume cavity expansion in some polymers above the glass transition temperature was investigated using experimental positron annihilation lifetime data from the literature for polydimethylsiloxane, polyisobutylene, and polybutadiene as function of temperature. The results suggest that free volume sites can expand towards an equilibrium size, determined as the equilibrium Ps-bubble size defined earlier for low-molecular-weight liquids. The expansion can be explained by the increase of molecular mobility and hence decrease of relaxation times, which at the higher temperatures approach the o-Ps lifetimes. Nanoscale viscosities were estimated using Navier-Stokes equation and were found to be several orders of magnitude lower than the macroscopic viscosity at the same temperature

Short-form measures of diabetes-related emotional distress: The Problem Areas in Diabetes Scale (PAID)-5 and PAID-1

Aims/hypothesis: We wanted to identify a five-item short form of the Problem Areas in Diabetes Scale and a single-item measure for rapid screening of diabetes-related emotional distress. Methods: Using an existing database of 1,153 patients with diabetes, we conducted a principal-components analysis to identify a set of five items and then conducted a reliability analysis and validity checks. From those five items, we identified the item with the strongest psychometric properties as a one-item screening tool. Results: We identified a reliable and valid short version of the Problem Areas in Diabetes Scale (PAID) comprising five of the emotional-distress questions of the full PAID items (PAID-5, with items 3, 6, 12, 16, 19). The PAID-5 has satisfactory sensitivity (94%) and specificity (89%) for recognition of diabetes-related emotional distress. We also identified a one-item screening tool, the PAID-1 (Question 12: Worrying about the future and the possibility of serious complications), which has concurrent sensitivity and specificity of about 80% for the recognition of diabetes-related emotional distress. Conclusions/ interpretation: The PAID-5 and PAID-1 appear to be psychometrically robust short-form measures of diabetes-related emotional distress.Centro de Endocrinología Experimental y Aplicad

On the stability of peptide nucleic acid duplexes in the presence of organic solvents

Nucleic acid double helices are stabilized by hydrogen bonding and stacking forces (a combination of hydrophobic, dispersive and electrostatic forces) of the base pairs in the helix. One would predict the hydrogen bonding contributions to increase and the stacking contributions to decrease as the water activity in the medium decreases. Study of nucleobase paired duplexes in the absence of water and ultimately in pure aprotic, non-polar organic solvents is not possible with natural phosphodiester nucleic acids due to the ionic phosphate groups and the associated cations, but could be possible with non-ionic nucleic acid analogues or mimics such as peptide nucleic acids. We now report that peptide nucleic acid (PNA) (in contrast to DNA) duplexes show almost unaffected stability in up to 70% dimethylformamide (DMF) or dioxane, and extrapolation of the data to conditions of 100% organic solvents indicates only minor (or no) destabilization of the PNA duplexes. Our data indicate that stacking forces contribute little if at all to the duplex stability under these conditions. The differences in behaviour between the PNA and the DNA duplexes are attributed to the differences in hydration and counter ion release rather than to the differences in nucleobase interaction. These results support the possibility of having stable nucleobase paired double helices in organic solvents

Short-form measures of diabetes-related emotional distress: The Problem Areas in Diabetes Scale (PAID)-5 and PAID-1

Aims/hypothesis: We wanted to identify a five-item short form of the Problem Areas in Diabetes Scale and a single-item measure for rapid screening of diabetes-related emotional distress. Methods: Using an existing database of 1,153 patients with diabetes, we conducted a principal-components analysis to identify a set of five items and then conducted a reliability analysis and validity checks. From those five items, we identified the item with the strongest psychometric properties as a one-item screening tool. Results: We identified a reliable and valid short version of the Problem Areas in Diabetes Scale (PAID) comprising five of the emotional-distress questions of the full PAID items (PAID-5, with items 3, 6, 12, 16, 19). The PAID-5 has satisfactory sensitivity (94%) and specificity (89%) for recognition of diabetes-related emotional distress. We also identified a one-item screening tool, the PAID-1 (Question 12: Worrying about the future and the possibility of serious complications), which has concurrent sensitivity and specificity of about 80% for the recognition of diabetes-related emotional distress. Conclusions/ interpretation: The PAID-5 and PAID-1 appear to be psychometrically robust short-form measures of diabetes-related emotional distress.Centro de Endocrinología Experimental y Aplicad

Biomarkers of Extracellular Matrix Metabolism (MMP-9 and TIMP-1) and Risk of Stroke, Myocardial Infarction, and Cause-Specific Mortality: Cohort Study

Objective: Turnover of the extracellular matrix in all solid organs is governed mainly by a balance between the degrading matrix metalloproteinases (MMPs) and their tissue inhibitors (TIMPs). An altered extracellular matrix metabolism has been implicated in a variety of diseases. We investigated relations of serum levels of MMP-9 and TIMP-1 to mortality risk from an etiological perspective. Design: The prospective Uppsala Longitudinal Study of Adult Men (ULSAM) cohort, followed from 1991–1995 for up to 18.1 years. A random population-based sample of 1,082 71-year-old men, no loss to follow-up. Endpoints were all-cause (n = 628), cardiovascular (n = 230), non-cardiovascular (n = 398) and cancer mortality (n = 178), and fatal or non-fatal myocardial infarction (n = 138) or stroke (n = 163). Results: Serum MMP-9 and TIMP-1 levels were associated with risk of all-cause mortality (Cox proportional hazard ratio [HR] per standard deviation 1.10, 95% confidence interval [CI] 1.03–1.19; and 1.11, 1.02–1.20; respectively). TIMP-1 levels were mainly related to risks of cardiovascular mortality and stroke (HR per standard deviation 1.22, 95% CI 1.09–1.37; and 1.18, 1.04–1.35; respectively). All relations except those of TIMP-1 to stroke risk were attenuated by adjustment for cardiovascular disease risk factors. Relations in a subsample without cardiovascular disease or cancer were similar to those in the total sample. Conclusion: In this community-based cohort of elderly men, serum MMP-9 and TIMP-1 levels were related to mortality risk. An altered extracellular matrix metabolism may be involved in several detrimental pathways, and circulating MMP-9 or TIMP-1 levels may be relevant markers thereof

Short-form measures of diabetes-related emotional distress: the Problem Areas in Diabetes Scale (PAID)-5 and PAID-1

AIMS/HYPOTHESIS: We wanted to identify a five-item short form of the Problem Areas in Diabetes Scale and a single-item measure for rapid screening of diabetes-related emotional distress. METHODS: Using an existing database of 1,153 patients with diabetes, we conducted a principal-components analysis to identify a set of five items and then conducted a reliability analysis and validity checks. From those five items, we identified the item with the strongest psychometric properties as a one-item screening tool. RESULTS: We identified a reliable and valid short version of the Problem Areas in Diabetes Scale (PAID) comprising five of the emotional-distress questions of the full PAID items (PAID-5, with items 3, 6, 12, 16, 19). The PAID-5 has satisfactory sensitivity (94%) and specificity (89%) for recognition of diabetes-related emotional distress. We also identified a one-item screening tool, the PAID-1 (Question 12: Worrying about the future and the possibility of serious complications), which has concurrent sensitivity and specificity of about 80% for the recognition of diabetes-related emotional distress. CONCLUSIONS/INTERPRETATION: The PAID-5 and PAID-1 appear to be psychometrically robust short-form measures of diabetes-related emotional distress

International Consortium of Vascular Registries Consensus Recommendations for Peripheral Revascularisation Registry Data Collection

Objective/Background: To achieve consensus on the minimum core data set for evaluation of peripheral arterial revascularisation outcomes and enable collaboration among international registries. Methods: A modified Delphi approach was used to achieve consensus among international vascular surgeons and registry members of the International Consortium of Vascular Registries (ICVR). Variables, including definitions, from registries covering open and endovascular surgery, representing 14 countries in ICVR, were collected and analysed to define a minimum core data set and to develop an optimum data set for registries. Up to three different levels of variable specification were suggested to allow inclusion of registries with simpler versus more complex data capture, while still allowing for data aggregation based on harmonised core definitions. Results: Among 31 invited experts, 25 completed five Delphi rounds via internet exchange and face to face discussions. In total, 187 different items from the various registry data forms were identified for potential inclusion in the recommended data set. Ultimately, 79 items were recommended for inclusion in minimum core data sets, including 65 items in the level 1 data set, and an additional 14 items in the more specific level 2 and 3 recommended data sets. Data elements were broadly divided into (i) patient characteristics; (ii) comorbidities; (iii) current medications; (iv) lesion treated; (v) procedure; (vi) bypass; (vii) endarterectomy (viii) catheter based intervention; (ix) complications; and (x) follow up. Conclusion: A modified Delphi study allowed 25 international vascular registry experts to achieve a consensus recommendation for a minimum core data set and an optimum data set for peripheral arterial revascularisation registries. Continued global harmonisation of registry infrastructure and definition of items will overcome limitations related to single country investigations and enhance the development of real world evidence. (C) 2018 European Society for Vascular Surgery. Published by Elsevier B.V. All rights reserved.Peer reviewe