An Overview of the Measurement of Permeability of Composite Reinforcements

Liquid composite molding (LCM) is a class of fast and cheap processes suitable for the fabrication of large parts with good geometrical and mechanical properties. One of the main steps in an LCM process is represented by the filling stage, during which a reinforcing fiber preform is impregnated with a low-viscosity resin. Darcy’s permeability is the key property for the filling stage, not usually available and depending on several factors. Permeability is also essential in computational modeling to reduce costly trial-and-error procedures during composite manufacturing. This review aims to present the most used and recent methods for permeability measurement. Several solutions, introduced to monitor resin flow within the preform and to calculate the in-plane and out-of-plane permeability, will be presented. Finally, the new trends toward reliable methods based mainly on non-invasive and possibly integrated sensors will be described

Effects of tanniferous browse plant supplementation on the nutrient digestibility and growth of Djallonk rams

Two separate experiments were conducted to investigate the effect of tanniferous (CT) browse plant supplementation on the growth, nutrient digestibility and blood biochemical properties of Djallonké sheep. The browse plants were Albizia lebbeck, Gmelina arborea, Senna siamea and Ceiba pentandra and were harvested from natural grazing fields within the vicinity of Nyankpala in Ghana. In experiment I, 20 semi-intensively kept Djallonké rams with average initial weight of 12.8±1.7 kg were randomly assigned four browse plants to evaluate their performance in terms of growth and blood biochemical properties. In experiment II, eight intensively managed Djallonké rams with an average initial weight of 13.8±1.56 kg were randomly assigned to a total mixed ration (TMR) made of browse plants, rice straw, minerals and vitamins to determine the nutrient digestibility. In experiment I, whereas lambs supplemented with the highest condensed tannin (CT) browse plant (C. Pentandra) had improved (P<0.05) ADWG compared to the control, it did not differ from the ADWG reported in lambs that were supplemented with A. lebbeck even though it did not contain measurable levels of CT. The blood metabolites did not differ among treatments. In experiment II, lambs fed with S. siamea ration had the lowest DMI with the highest reported in G. arborea. Lambs fed with A. lebbeck TMR had the highest (P<0.05) CP digestibility and nitrogen balance. The lowest NDF and ADF digestibility were obtained in animals fed the G. arborea diet. The tanniferous browse plants used in this experiment were high in nutritive value and resulted in improved live weight of lambs. They could be fed as supplement to lambs grazing natural pasture during periods of feeds scarcity

Nebivolol: haemodynamic effects and clinical significance of combined beta-blockade and nitric oxide release.

Nebivolol is a third-generation beta-adrenergic receptor antagonist (beta-blocker) with high selectivity for beta(1)-adrenergic receptors. In addition, it causes vasodilatation via interaction with the endothelial L-arginine/nitric oxide (NO) pathway. This dual mechanism of action underlies many of the haemodynamic properties of nebivolol, which include reductions in heart rate and blood pressure (BP), and improvements in systolic and diastolic function. With respect to BP lowering, the NO-mediated effects cause a reduction in peripheral vascular resistance and an increase in stroke volume with preservation of cardiac output. Flow-mediated dilatation and coronary flow reserve are also increased during nebivolol administration. Other haemodynamic effects include beneficial effects on pulmonary artery pressure, pulmonary wedge pressure, exercise capacity and left ventricular ejection fraction. In addition, nebivolol does not appear to have adverse effects on lipid metabolism and insulin sensitivity like traditional beta-blockers. The documented beneficial haemodynamic effects of nebivolol are translated into improved clinical outcomes in patients with hypertension or heart failure. In patients with hypertension, the incidence of bradycardia with nebivolol is often lower than that with other currently available beta-blockers. This, along with peripheral vasodilatation and NO-induced benefits such as antioxidant activity and reversal of endothelial dysfunction, should facilitate better protection from cardiovascular events. In addition, nebivolol has shown an improved tolerability profile, particularly with respect to events commonly associated with beta-blockers, such as fatigue and sexual dysfunction. Data from SENIORS (Study of the Effects of Nebivolol Intervention on Outcomes and Rehospitalization in Seniors with Heart Failure) showed that significantly fewer nebivolol versus placebo recipients experienced the primary endpoint of all-cause mortality or cardiovascular hospitalization. The benefits of nebivolol therapy were shown to be cost effective. Thus, nebivolol is an effective and well tolerated agent with benefits over and above those of traditional beta-blockade because of its effects on NO release, which give it unique haemodynamic effects, cardioprotective activity and a good tolerability profile

Pasos (Segunda época no. 138 jul-ago 2008)

América Latina y el Caribe 2008: una región en erupción, Manuel Hidalgo 1; La Iglesia en América Latina y el caribe: ¿está edificada sobre roca o sobre arena?, Pablo Richard 11; Con la lengua del despojo: un diálogo entre epistemología e identidades en América Latina y el Caribe, Silvia Regina de Lima Silva 23

Multicentric Castleman's Disease in a Ghanaian Adult

Castleman’s disease is a rare cause of lymphoid hyperplasia that may result in localized symptoms or an aggressive, multisystem disorder that can mimic other diseases like lymphoma or tuberculosis. We describe a case of a 55-year-old Ghanaian male who was successfully diagnosed and managed for multicentric Castleman’s disease with combination chemotherapy.Keywords: multicentric Castleman’s disease, Plasma cell, lymphadenopathy, chemotherapy, Rituxima

Bleomycin-induced pneumonitis in a young Ghanaian male with Hodgkin’s Lymphoma

We report a case of a young Ghanaian male who developed Bleomycin Induced Pneumonitis (BIP) after being treated for Hodgkin’s Lymphoma. Pulmonary toxicity is the most feared complication of bleomycin therapy despite its effectiveness in achieving cure in patients with Hodgkin’s lymphoma and germ cell tumors. BIP has a significant mortality rate if detected late and a high index of suspicion is required in all patients on bleomycin-based therapies with sudden onset of respiratory symptoms

Feed resource availability and fodder markets in northern Ghana

United States Agency for International Developmen

Performance analysis and design optimization of parallel-type slew-rate enhancers for switched-capacitor applications

The design of single-stage OTAs for accurate switched-capacitor circuits involves challenging trade-offs between speed and power consumption. The addition of a Slew-Rate Enhancer (SRE) circuit placed in parallel to the main OTA (parallel-type SRE) constitutes a viable solution to reduce the settling time, at the cost of low-power overhead and no modifications of the main OTA. In this work, a practical analytical model has been developed to predict the settling time reduction achievable with OTA/SRE systems and to show the effect of the various design parameters. The model has been applied to a real case, consisting of the combination of a standard folded-cascode OTA with an existing parallel-type SRE solution. Simulations performed on a circuit designed with a commercial 180-nm CMOS technology revealed that the actual settling-time reduction was significantly smaller than predicted by the model. This discrepancy was explained by taking into account the internal delays of the SRE, which is exacerbated when a high output current gain is combined with high power efficiency. To overcome this problem, we propose a simple modification of the original SRE circuit, consisting in the addition of a single capacitor which temporarily boosts the OTA/SRE currents reducing the internal turn-on delay. With the proposed approach a settling-time reduction of 57% has been demonstrated with an SRE that introduces only a 10% power-overhead with respect of the single OTA solution. The robustness of the results have been validated by means of Monte-Carlo simulations