Peningkatan Ketahanan Oksidasi Karet Alam Melalui Pengikatan Antioksidan 4-aminodifenilamina Secara Kimia

Natural rubber is very important in supporting the Indonesian economy from non-oil sector. However, natural rubber is not resistant to oxidation. Various attempts have been made to overcome the weaknesses; one of them is the addition of antioxidants as additives in the manufacture of rubber goods. However, it has the disadvantage of mechanical technique, including antioxidant blooming, resulting in failed products and decrease in antioxidants ability. The aim of this research is to improve the resistance of natural rubber from oxidation through the chemically-bound antioxidant into epoxidized latex. Fresh latex was deproteinized using 0.06 phr papain. Latex was epoxidized using formic acid and hydrogen peroxide at 70°C with stirring speed of 700 rpm for 3 hours. Then the 4-Aminodiphenylamine (4-ADPA) antioxidant was added with three variations mole percent of 4-ADPA between 0.025 to 0.1 mol/100 grams of rubber, and four variations in temperature were applied (between 27-80°C). The results showed that the optimum condition for the binding was at 27°C at a dose of antioxidants as much as 0.1 mol/100 grams of rubber. The analysis of FTIR spectra revealed that the binding of 4-ADPA into the epoxidized latex was as much as 1.93 phr. The Rheometer curve analysis showed that the natural rubber bound 4-ADPA was more resistant to ageing based on the value of R300

Design of a Database of Case Studies and Technologies to Increase the Diffusion of Low-Temperature Waste Heat Recovery in the Industrial Sector

The recovery of waste heat is a fundamental means of achieving the ambitious medium- and long-term targets set by European and international directives. Despite the large availability of waste heat, especially at low temperatures (<250 degrees C), the implementation rate of heat recovery interventions is still low, mainly due to non-technical barriers. To overcome this limitation, this work aims to develop two distinct databases containing waste heat recovery case studies and technologies as a novel tool to enhance knowledge transfer in the industrial sector. Through an in-depth analysis of the scientific literature, the two databases' structures were developed, defining fields and information to collect, and then a preliminary population was performed. Both databases were validated by interacting with companies which operate in the heat recovery technology market and which are possible users of the tools. Those proposed are the first example in the literature of databases completely focused on low-temperature waste heat recovery in the industrial sector and able to provide detailed information on heat exchange and the technologies used. The tools proposed are two key elements in supporting companies in all the phases of a heat recovery intervention: from identifying waste heat to choosing the best technology to be adopted

Acute kidney injury and outcome following aortic valve replacement for aortic stenosis.

To access publisher's full text version of this article, please click on the hyperlink in Additional Links field or click on the hyperlink at the top of the page marked Files. This article is open access.Most studies on acute kidney injury (AKI) following open-heart surgery have focused on short-term outcome following coronary artery bypass grafting. We reviewed the incidence, risk factors and outcome, including long-term survival, of AKI after aortic valve replacement (AVR) in a population-based cohort.A retrospective review of 365 patients who underwent AVR for aortic stenosis during 2002-2011 was made. AKI was defined according to the RIFLE criteria. All patients requiring dialysis were followed up in a centralized registry. Risk factors for AKI were analysed with univariable and multivariable analysis, and survival was graphically presented with the Kaplan-Meier method.The rate of AKI was 82/365 (22.5%); 40, 28 and 14 patients belonging to the Risk, Injury and Failure groups, respectively. Preoperatively, 37 (45.1%) AKI patients had reduced kidney function. Transfusion of red blood cells, obesity and prolonged cardiopulmonary bypass time were independent risk factors for AKI. Acute postoperative dialysis was required in 15 patients (4.1%), and 1 patient developed dialysis-dependent end-stage renal disease. Major postoperative complications were more common in the AKI group (65 vs 22%, P < 0.001). The 30-day mortality rate in the AKI group was 18%, as opposed to 2% in the non-AKI group (P < 0.001), with a 5-year survival rate of 66 vs 87%, respectively (P < 0.001). In multivariable analysis AKI was an independent predictor of operative mortality [odds ratio = 5.89, 95% confidence interval (CI) = 1.99-18.91] but not of long-term survival (hazard ratio = 1.44, 95% CI = 0.86-2.42).More than 1 in 5 patients (22.5%) who underwent AVR developed AKI postoperatively. AKI was associated with higher morbidity and was an independent predictor of operative mortality. However, AKI was not a determinant of long-term survival.Landspitali University Research Fund, University of Iceland Research Fund, Helga Gudmundsdottir and Sigurlidi Kristjansson Memorial Fund

Harmonic oscillator with nonzero minimal uncertainties in both position and momentum in a SUSYQM framework

In the context of a two-parameter $(\alpha, \beta)$ deformation of the canonical commutation relation leading to nonzero minimal uncertainties in both position and momentum, the harmonic oscillator spectrum and eigenvectors are determined by using techniques of supersymmetric quantum mechanics combined with shape invariance under parameter scaling. The resulting supersymmetric partner Hamiltonians correspond to different masses and frequencies. The exponential spectrum is proved to reduce to a previously found quadratic spectrum whenever one of the parameters $\alpha$, $\beta$ vanishes, in which case shape invariance under parameter translation occurs. In the special case where $\alpha = \beta \ne 0$, the oscillator Hamiltonian is shown to coincide with that of the q-deformed oscillator with $q > 1$ and its eigenvectors are therefore $n$-$q$-boson states. In the general case where $0 \ne \alpha \ne \beta \ne 0$, the eigenvectors are constructed as linear combinations of $n$-$q$-boson states by resorting to a Bargmann representation of the latter and to $q$-differential calculus. They are finally expressed in terms of a $q$-exponential and little $q$-Jacobi polynomials.Comment: LaTeX, 24 pages, no figure, minor changes, additional references, final version to be published in JP

The Relationship between Fisheries and Farming

Fishmeal is a critically important feed ingredient for use in animal (e.g., poultry and pork) and aquaculture production (e.g., salmon, trout, and shrimp). There is concern that demand for fishmeal may place additional stress on the world’s pelagic fisheries and may undermine the sustainability of some aquaculture systems that rely on fishmeal. Our research suggests that since 1998 market for fishmeal has changed. An important explanation is likely to be the increasing use of specialized feed formulations in the pork, poultry and aquaculture sectors. It is clear that growth in aquaculture production alone is insufficient to explain the structural change since growth in the use of fishmeal in aquaculture has slowed considerably despite the continued rapid growth in global aquaculture sector. The increasing relative price of fishmeal is likely to increase costs for animal producers, act as a stimulus for innovation and have considerable implications for the management of pelagic fisheries.Keywords: Interrelations between Aquaculture/Animal Production and Fisheries, Structural ChangeKeywords: Interrelations between Aquaculture/Animal Production and Fisheries, Structural Chang

Effect of antenatal depression on adverse birth outcomes in Gondar town, Ethiopia: A community-based cohort study

Published: June 17, 2020BACKGROUND:The impact of antenatal depression on pregnancy outcomes has been well investigated in developed countries, but few studies have been conducted in low-income countries. As depression is significantly affected by socio-economic and cultural factors, it would be difficult to generalize evidence from high-income countries to low-income countries. We conducted a community-based cohort study to estimate the incidence of adverse birth outcomes and the direct and indirect pathways via which depression and other psychosocial risk factors may impact such birth outcomes within Gondar town, Ethiopia. METHODS:The study followed 916 pregnant women who were screened for antenatal depression using the Edinburgh Postnatal Depression Scale (EPDS). We also assessed the incidence of preterm births, Low Birth Weight (LBW) and stillbirths. Modified Poisson regression was used to estimate the relative risk of predictors on adverse birth outcomes and a Generalized Structural Equation Model (GSEM) was used to estimate the direct and indirect effect of antenatal depression and other psychological risk factors on adverse birth outcomes. RESULTS:The cumulative incidence of stillbirth, LBW and preterm was 1.90%, 5.25%, and 16.42%, respectively. The risk of preterm birth was 1.61, 1.46, 1.49, and 1.77 times higher among participants who identified as Muslim, reported being fearful of delivery, were government employee's, and who had no antenatal care services, respectively. Partner support moderated the association between depression, preterm birth, and LBW. Depression had no direct effect on birth outcomes but indirectly affected preterm birth via partner support. Religion had both direct and indirect effects on preterm birth, while occupation and fear of delivery had direct effects. The risk of LBW was 9.44 and 2.19 times higher among preterm births and those who had exposure to tobacco, respectively. Stress coping was indirectly associated, and preterm birth and tobacco exposure were directly associated with LBW. The risk of stillbirth was 3.22 times higher in women with antenatal depression and 73% lower in women with higher coping abilities. CONCLUSIONS:There was a high incidence of all adverse birth outcomes in Gondar Town. Depression and psychosocial risk factors had important indirect negative effects on risk, while partner support provided a positive indirect effect on the incidence of adverse birth outcomes. Interventions that focus on increasing partner engagement and participation in antenatal support may help reduce adverse birth outcomes by enhancing maternal resilience.Abel Fekadu Dadi, Emma R. Miller, Richard J. Woodman, Telake Azale, Lillian Mwanr