Alternating copolyesteramides based on mixtures of 1,4-butyleneterephthalamide and -isophthalamide and ethanediol (4NT/I2)

Alternating copolyesteramides (APEA's) consisting of mixtures of 1,4-butyleneterephthalamide ester (N,N′-bis(p-carbomethoxybenzoyl) diaminobutane) and 1,4-butyleneisophthalamide ester (N,N′-bis(m-carbomethoxybenzoyl) diaminobutane) polymerized with ethanediol were synthesised in an ethanediol solution. The bisesterdiamides were prepared from 1,4-butanediamine and dimethyl terephthalate or dimethylisophthalate respectively. They were analyzed by 1H n.m.r., differential scanning calorimetry (d.s.c.) and high pressure liquid chromatography (h.p.l.c.). The melting behaviour of the copolyesteramides was studied by d.s.c. The dynamic mechanical properties were investigated on injection moulded bars using dynamic mechanical thermal analysis (DMTA). The melting temperature decreased with increasing 1,4-butyleneisophthalamide ester content. The crystallisation rate, the modulus above the glass transition temperature and the glass transition temperature hardly changed. The APEA of 1,4-butyleneisophthalamide ester and ethanediol was amorphous. The lowering of the melting temperature of the copolymers was probably caused by a decrease in lamellar size. The high crystallisation rate and the high physical crosslink density of the copolymers must be ascribed to the presence of 1,4-butyleneterephthalamide ester units which are able to crystallise fast and to form strong crystallites

Characterization of polyacrylonitrile ultrafiltration membranes

Various methods have been used to characterize ultrafiltration membranes, such as gas flux measurements, (field emission) scanning electron microscopy, permporometry and liquid-liquid displacement. Significant differences in the pore size distributions determined from permporometry and liquid-liquid displacement were found

Kiribati: religious practices

A revised update of an entry on Kiribati in the Worldmark Encyclopedia of Religious Practices. It looks at a brief history of religious practices in Kiribati, especially of the major Christian Churches. The entry is a brief bird's eye view of the narrative of the Christian Churches as well as some of the indigenous religions practices before the arrival of Christianity

Polyesteramides based on PET and nylon 2,T part 1. synthesis of the bisesterdiamide

The synthesis of the bisesterdiamide T2T-dimethyl (one-and-a-half repeating unit of nylon 2,T) (benzoic acid, 4,4′-[1,2–ethanediylbis(iminocarbonyl)] bis-dimethyl ester, CAS no 7060-10-8) has been studied using dimethyl terephthalate (DMT) and 1,2-diaminoethane (DAE) as starting materials. T2T-dimethyl was synthesised in a solvent mixture of toluene/methanol at 65°C employing lithium or sodium methanolate as a catalyst. The progress of reaction was followed as function of time using liquid chomatrography and endgroup titrations. The products were analysed using 1H NMR, 13C NMR and differential scanning calorimeter. A high yield was obtained (90%), and after recrystallisation from NMP, the product was found to be of high purity. The pure T2T-dimethyl obtained had a melting onset of 312°C and a melting enthalpy of 165 J/g.\ud \ud T2T-dimethyl was also synthesised in absence of a catalyst at 100°C and using m-xylene as solvent and at a high concentration of reactants. The yield of this reaction was relatively low (34%). The addition of phenol to the reaction mixture had little effect on the yield and purity of the product

Pro-poor intervention strategies in irrigated agriculture in Asia: poverty in irrigated agriculture: issues and options: India

Irrigated farming / Poverty / Institutions / Irrigation programs / Performance evaluation / Irrigation management / Water distribution / Water rates / Cost recovery / India

Onderzoek voor de eendenhouderij

In Nederland worden per jaar ongeveer 4 miljoen slachteenden geproduceerd. De productie vindt voor meer dan 80% plaats in de gemeenten Ermelo en Harderwijk. Eenden worden voornamelijk buiten gehouden. Deze buitenhouderij veroorzaakt een zware belasting van het milieu

Intravascular Polarimetry: Clinical Translation and Future Applications of Catheter-Based Polarization Sensitive Optical Frequency Domain Imaging

Optical coherence tomography (OCT) and optical frequency domain imaging (OFDI) visualize the coronary artery wall and plaque morphology in great detail. The advent of these high-resolution intracoronary imaging modalities has propelled our understanding of coronary atherosclerosis and provided enhanced guidance for percutaneous coronary intervention. Yet, the lack of contrast between distinct tissue types and plaque compositions impedes further elucidation of the complex mechanisms that contribute to acute coronary syndrome (ACS) and hinders the prospective identification of plaques susceptible to rupture. Intravascular polarimetry with polarization-sensitive OFDI measures polarization properties of the coronary arterial wall using conventional intravascular imaging catheters. The quantitative polarization metrics display notable image contrast between several relevant coronary plaque microstructures that are difficult to identify with conventional OCT and OFDI. Tissues rich in collagen and smooth muscle cells exhibit birefringence, while lipid and macrophages cause depolarization. In this review, we describe the basic principles of intravascular polarimetry, discuss the interpretation of the polarization signatures, and outline promising avenues for future research and clinical implications

Aortic valve replacement in octogenarians

<p>Abstract</p> <p>Background and Aims</p> <p>As our population ages and life expectancy increases the number of people aged over 80 and more referred for cardiac surgery is growing. This study sought to identify the outcome of aortic valve replacement (AVR) in octogenarians.</p> <p>Methods</p> <p>68 patients aged 80 years or more underwent AVR at the Freeman Hospital, between April 2001 and April 2004. A retrospective review of the notes and outcomes from the patients' GP and the NHS strategic tracking service was performed. 54% (37) underwent isolated AVR whilst 46% (31) underwent combined AVR and CABG.</p> <p>Results</p> <p>Follow up was 100% complete. The mean age was 83.1 ± s.d. 2.9 years, a mean gradient of 83 ± s.d. 31 mmHg and mean AVA of 0.56 cm². The mean additive EuroSCORE was 8.6 ± s.d. 1.2, the logistic EuroSCORE mean 12.0 ± s.d. 5.9. In hospital 30 day mortality was 13 %. Survival was 80% at 1 year and 78% at 2 years. Median follow up was for 712 days. Stepwise logistic regression identified chronic obstructive airways disease as an independent predictor of mortality (p < 0.05). Survival was not adversely affected by the addition of coronary artery bypass grafts to aortic valve replacement, the presence of peripheral vascular disease, hypertension or diabetes. In this study duration of cross clamp or bypass time were not found to reach significance as independent predictors of mortality.</p> <p>Conclusion</p> <p>Our study demonstrates that the operative mortality for AVR in the over eighties is good, whilst the mid to long term outcome is excellent There is a very low attrition rate with those undergoing the procedure living as long than their age matched population. This study confirms AVR is a safe, acceptable treatment for octogenarians with excellent mid term outcomes.</p