Degradation of epoxy coatings under gamma irradiation

Epoxy networks based on Diglycidyl ether of bisphenol A (DGEBA) and cured with Jeffamines (POPA) or polyamidoamine (PAA) were gamma irradiated at 25 1C in air. Dose rates of 50, 200 or 2000 Gy h- 1 for doses up 100 kGy were used. Structural changes were monitored by IR spectrophotometry, DSC and sol–gel analysis. Both networks display some common features: for I Z 200 Gy h- 1, reaction products grow proportionally to time and the rate is a decreasing function of dose rate. The simplest explanation is that peroxy radicals are the main precursors of these products (in the dose rate domain under study), through a unimolecular rearrangement of which an hypothetical mechanism is proposed. DGEBA–POPA are more reactive then DGEBA–PAA networks (according to IR criteria), that can be attributed to the high reactivity of tertiary CH bands in polyoxypropylene segments. The oxidation of these sites leads to methyl ketones. A simple kinetic model in which methyl ketones result from rearrangements of tertiary peroxyls and from tertiary alkoxyls was proposed. It leads to an expression of the radiochemical yield of methyl ketones (G(MK)) of the form GðMKÞ¼ a þ bI-1=2 where a and b are parameters depending of elementary rate constants. Experimental G(MK) values are reasonably well fitted by this equation. In DGEBA–PAA networks, a wide variety of oxidation products, among which amides predominate, can be observed. In these networks, chain scissions predominate over crosslinking, whereas a slight predominance of crosslinking was observed, at least for the lowest dose rate, in DGEBA–POPA

Thermo-oxidative aging of epoxy coating systems

tThe thermo-oxidative behavior of unformulated (unfilled) samples of epoxy coatings has been studiedat five temperatures ranging from 70◦C to 150◦C. Two epoxy networks based on diglycidyl ether ofbisphenol A (DGEBA), respectively, cured by jeffamine (POPA) or polyamidoamine (PAA) were compared.Infrared spectrophotometry (IR), differential scanning (DSC) and sol–gel analysis (SGA) were used tomonitor structural changes.Thermal oxidation leads to carbonyl and amide formation in both systems. POPA systems appear moresensitive to oxidation than PAA ones. Thermal oxidation leads to predominant chain scission as evidencedby the decrease of glass transition temperatures (Tg) and increase of sol fraction

Proceedings of the Conference on Globalization and Its Discontents

Recent studies on economic globalization have used various indicators, such as the ratio of trade-to-GDP and the ratio of FDI-to-GDP, to analyze the globalization performances of national economies. Although each indicator is useful in itself, our contention is that a single composite indicator (index) can provide more comprehensive information and would enable policy-makers and researchers to compare and rank the globalization performances of different countries, country groups and regions in a given year (or period) and over time. Accordingly, in this paper, we developed the economic globalization index to measure the extent of globalization of national economies. We have constructed the economic globalization index for the period 1975-2005. The overall results indicate that rich countries tend to be more globalized than poor countries. Furthermore, rich countries have improved their globalization –relative global integration level- from 1975 to 2005; however, many of poor countries’ relative levels of global integration have deteriorated during the same period. Our results seem to be in line with studies that characterize the recent situation in the world as “truncated globalization” or simply “triadization”.globalization, economic globalization index

Sensitivity analysis for parametric vector optimization problems using differential equations approach

A new method for obtaining sensitivity information for parametric vector optimization problems (VOP)v is presented, where the parameters in the objective functions and anywhere in the constraints. This method depends on using differential equations technique for solving multiobjective nonlinear programing problems which is very effective in finding many local Pareto optimal solutions. The behavior of the local solutions for slight perturbation of the parameters in the neighborhood of their chosen initial values is presented by using the technique of trajectory continuation. Finally some examples are given to show the efficiency of the proposed method

Sjögren Syndrome Complicated by Mucosa-Associated Lymphoid Tissue Lymphoma and Lymphocytic Interstitial Pneumonia.

Sjögren syndrome (SS) is an autoimmune disease with exocrine glands dysfunction and multiorgan involvement. It is associated with increased risk of lymphoproliferative disorders, especially B-cell marginal zone lymphoma. While the role of F-18 Fluorodeoxyglucose position emission tomography/computed tomography (F-18 FDG PET/CT) for evaluation of lymphoma has been established, its use in patients with a chronic history of SS to evaluate for possible lymphoproliferative disorders or multiorgan involvement is limited. We present a case of chronic SS in which F-18 FDG PET/CT demonstrated FDG avid intraparotid and cervical lymph nodes pathologically proven to be mucosa-associated lymphoid tissue lymphoma. In addition, the patient had bibasilar cystic changes consistent with lymphocytic interstitial pneumonia

Ketahanan Enam Klon Karet Terhadap Infeksi Corynespora Cassiicola Penyebab Penyakit Gugur Daun

Resistance of six rubber clones to Corynespora cassiicola the pathogen of rubber leaf fall disease. The objectives of the research was to evaluate the resistance of six rubber clones to Corynespora cassiicola, the pathogen of rubber leaf fall disease. The research was conducted at Phytophatology laboratorium and green house at the Plant Pest and Diseases Department, Faculty of Agriculture, Sriwijaya University, from March to July 2008. The treatments were arranged in a completely randomized block design (CRBD) with six treatments and four replications. Each replication consisted of four polibags of rubber plants. The clons tested were GT 1, PB 260, IRR 39, BPM 1, BPM 24 and PR 261. The results showed that IRR 39 was the most susceptible clon to C. cassiicola infection, whereas disease severety reach up to 98.45 % and leaf fall 73.95 %. Clon PB 260 show as the moderat resistance clon to the pathogen infection. The severity disease of this clon only 41.53 % and leaf fall 10.41%

Serum vitamin D in patients with mild cognitive impairment and Alzheimer's disease

Objectives: To determine the relevance of Mini-Mental State Examination (MMSE), serum 25-hydroxyvitamin D (25(OH)D3), and 1,25(OH)2D3 concentrations to mild cognitive impairment (MCI) and various stages of Alzheimer's disease (AD). Materials and Methods: The study included 230 participants (>74 years) allocated to three main groups: 1-healthy subjects (HS, n = 61), 2-patients with MCI (n = 61), and 3- patients with Alzheimer's disease (AD) subdivided into three stages: mild (n = 41), moderate (n = 35), and severe AD (n = 32). The cognitive status was evaluated using MMSE. Serum 25 (OH)D3 (ng/ml) and 1,25(OH)2D3 concentrations (pg/ml) were determined by competitive radioimmunoassay. Results: MMSE scores and 25(OH)D3 were decreased in MCI and all stages of the AD in both genders. MMSE variability was due to gender in HS (11%) and to 25(OH)D3 in MCI (15%) and AD (26%). ROC analysis revealed an outstanding property of MMSE in diagnosis of MCI (AUC, 0.906; CI 95%, 0.847–0.965; sensitivity 82%; specificity, 98%) and AD (AUC, 0.997; CI 95%, 0.992–1; sensitivity, 100%; specificity, 98%). 25(OH)D3 exhibited good property in MCI (AUC, 0.765; CI 95%, 0.681–0.849; sensitivity, 90%; specificity, 54%) and an excellent property in diagnosis of AD (AUC, 0.843; CI 95%, 0.782–0.904; sensitivity, 97%; specificity, 79%). Logistic analyses revealed that, in MCI, MMSE could predict (or classify correctly) with 97.6% accuracy (Wald, 15.22, β, −0.162; SE, 0.554; OR = 0.115:0.039–0.341; p =.0001), whereas 25(OH)D3 with 80% accuracy (Wald, 41,013; β, −0.213; SE, 0.033; OR = 0.808: 0.757–863; p =.0001). 25(OH)D3 was the only significant predictor for the severe AD and contributed to MMSE variability. Age and gender were significant predictors only in the moderate AD. In patients with MCI, 25(OH)D3 and 1,25(OH)2D3 were correlated men, but in case of the AD, they were correlated in women. Conclusions: MMSE and serum 25(OH)D3 concentrations could be useful biomarkers for prediction and diagnosis of MCI and various stages of the AD. The results support the utility of vitamin D supplementation in AD therapy regimen. © 2018 The Authors. Brain and Behavior published by Wiley Periodicals, Inc

Future-Proofing Dietary Pea Starch

info:eu-repo/semantics/acceptedVersio