Stability of a strongly anisotropic thin epitaxial film in a wetting interaction with elastic substrate

The linear dispersion relation for longwave surface perturbations, as derived by Levine et al. Phys. Rev. B 75, 205312 (2007) is extended to include a smooth surface energy anisotropy function with a variable anisotropy strength (from weak to strong, such that sharp corners and slightly curved facets occur on the corresponding Wulff shape). Through detailed parametric studies it is shown that a combination of a wetting interaction and strong anisotropy, and even a wetting interaction alone results in complicated linear stability characteristics of strained and unstrained films. PACS: 68.55.J, Morphology of films; 81.15.Aa, Theory and models of film growth; 81.16.Dn, Self-assembly.Comment: Accepted in EPL (http://epljournal.edpsciences.org

Thin-Film Evolution Equation for a Strained Solid Film on a Deformable Substrate: Numerical Steady States

We consider the nonlinear behavior of the thin-film evolution equation for a strained solid film on a substrate. The evolution equation describes morphological changes to the film by surface diffusion in response to elastic energy, surface energy, and wetting energy. Due to the thin-film approximation, the elastic response of the film is determined analytically, resulting in a self-contained evolution equation which does not require separate numerical solution of the full three-dimensional elasticity problem. Using a pseudospectral predictor-corrector method we numerically determine the family of steady state solutions to this evolution equation which correspond to quantum dot and quantum ridge morphologies

Delay in initiating tuberculosis treatment and factors associated among pulmonary tuberculosis patients in East Wollega, Western Ethiopia

Background: Delay in treatment is also likely to be associated with a greater number of secondary cases per index case. Objective: to assess the length of patient and health system delays; and identify factors influencing these delays among pulmonary tuberculosis patients. Methods: We conducted a cross-sectional study in 13 selected government health facilities that provide both diagnostic and treatment services using Directly Observed Treatment Short course (DOTS) program. Data were collected from pulmonary TB patients aged 15 years and above during their intensive phase of DOTS treatment using a semi-structured questionnaire. Results: The median total delay was 90 days; with 28 days patient delay and 42 days health system delay. A large proportion (63%) of the overall total delay was contributed by health system delay. Patients from urban areas were 46% more likely to present to health care providers than patients from rural areas, adjusted hazard ratio (AHR) of 1.46 (95% CI: 1.10 - 1.95). Patients from urban areas were 54% more likely to be diagnosed and start treatment earlier than patients from rural areas, AHR of 1.54 (95% CI: 1.15-2.07). Female patients were more delayed to present to health providers than their male counterparts with AHR of 0.63 (95%CI: 0.47–0.84) but had shorter health system delay than male patients with AHR of 1.51 (95% CI: 1.1-22.04). Conclusion: A greater proportion of the overall total delay was contributed by health system delay. The health system should be more accessible for the unmet need. New approaches to make health services more accessible to those in greatest need (rural and women) should be designed and developed.The Ethiopian Journal of Health Development Vol. 21 (2) 2007: pp. 148-15

Metal and metalloid speciation in plants : overview, instrumentation, approaches and commonly assessed elements

The ability of plants to hyper-accumulate metals and metalloids from the surrounding environment may pose a significant health risk to both humans and animals since plants form a substantial component of diet. This attribute, however, has also been identified as a useful tool in bioremediation and biomonitoring studies; where assimilated metal(loid)s in plants often correlate to environmental exposure. Since the bioavailability and toxicity of these elements depends upon their chemical form, speciation studies are essential in determining mobility and metabolic pathways. This can be done in a number of ways where sampling, pre-treatment and storage are all important factors affecting speciation. Appropriate analytical techniques for speciation studies can either be direct methods such as XAS, or indirect methods which require species separation prior to analysis. Separation techniques can be in the form of sequential extractions or column separation and analyte detection often utilises instrumentation such as ESI-MS, ICP-MS and ICP-OES.University of Pretoria and the University of Johannesburg.http://www.journals.elsevier.com/trends-in-analytical-chemistry2017-03-31hb2016Chemistr

All-polymer photonic sensing platform based on whispering-gallery mode microgoblet lasers

We present an all-polymer photonic sensing platform based on whispering-gallery mode microgoblet lasers integrated into a microfluidic chip. The chip is entirely made from polymers, enabling the use of the devices as low-cost disposables. The microgoblet cavities feature quality factors exceeding 105 and are fabricated from poly(methyl methacrylate) (PMMA) using spin-coating, mask-based optical lithography, wet chemical etching, and thermal reflow. In contrast to silica-based microtoroid resonators, this approach replaces technically demanding vacuum-based dry etching and serial laser-based reflow techniques by solution-based processing and parallel thermal reflow. This enables scaling to large-area substrates, and hence significantly reduces device costs. Moreover, the resonators can be fabricated on arbitrary substrate materials, e.g., on transparent and flexible polymer foils. Doping the microgoblets with the organic dye pyrromethene 597 transforms the passive resonators into lasers. Devices have lasing thresholds below 0.6 nJ per pulse and can be efficiently pumped via free-space optics using a compact and low-cost green laser diode. We demonstrate that arrays of microgoblet lasers can be readily integrated into a state-of-the-art microfluidic chip replicated via injection moulding. In a proof-of-principle experiment, we show the viability of the lab-on-a-chip via refractometric sensing, demonstrating a bulk refractive index sensitivity (BRIS) of 10.56 nm per refractive index unit. © The Royal Society of Chemistry 2015

Haemoglobin mass and running time trial performance after recombinant human erythropoietin administration in trained men

<p>Recombinant human erythropoietin (rHuEpo) increases haemoglobin mass (Hbmass) and maximal oxygen uptake (v˙ O2 max).</p> <p>Purpose: This study defined the time course of changes in Hbmass, v˙ O2 max as well as running time trial performance following 4 weeks of rHuEpo administration to determine whether the laboratory observations would translate into actual improvements in running performance in the field.</p> <p>Methods: 19 trained men received rHuEpo injections of 50 IUNkg21 body mass every two days for 4 weeks. Hbmass was determined weekly using the optimized carbon monoxide rebreathing method until 4 weeks after administration. v˙ O2 max and 3,000 m time trial performance were measured pre, post administration and at the end of the study.</p> <p>Results: Relative to baseline, running performance significantly improved by ,6% after administration (10:3061:07 min:sec vs. 11:0861:15 min:sec, p,0.001) and remained significantly enhanced by ,3% 4 weeks after administration (10:4661:13 min:sec, p,0.001), while v˙ O2 max was also significantly increased post administration (60.765.8 mLNmin21Nkg21 vs. 56.066.2 mLNmin21Nkg21, p,0.001) and remained significantly increased 4 weeks after rHuEpo (58.065.6 mLNmin21Nkg21, p = 0.021). Hbmass was significantly increased at the end of administration compared to baseline (15.261.5 gNkg21 vs. 12.761.2 gNkg21, p,0.001). The rate of decrease in Hbmass toward baseline values post rHuEpo was similar to that of the increase during administration (20.53 gNkg21Nwk21, 95% confidence interval (CI) (20.68, 20.38) vs. 0.54 gNkg21Nwk21, CI (0.46, 0.63)) but Hbmass was still significantly elevated 4 weeks after administration compared to baseline (13.761.1 gNkg21, p<0.001).</p> <p>Conclusion: Running performance was improved following 4 weeks of rHuEpo and remained elevated 4 weeks after administration compared to baseline. These field performance effects coincided with rHuEpo-induced elevated v˙ O2 max and Hbmass.</p&gt

Traditional medicinal plant knowledge and use by local healers in Sekoru District, Jimma Zone, Southwestern Ethiopia

The knowledge and use of medicinal plant species by traditional healers was investigated in Sekoru District, Jimma Zone, Southwestern Ethiopia from December 2005 to November 2006. Traditional healers of the study area were selected randomly and interviewed with the help of translators to gather information on the knowledge and use of medicinal plants used as a remedy for human ailments in the study area. In the current study, it was reported that 27 plant species belonging to 27 genera and 18 families were commonly used to treat various human ailments. Most of these species (85.71%) were wild and harvested mainly for their leaves (64.52%). The most cited ethnomedicinal plant species was Alysicarpus quartinianus A. Rich., whose roots and leaves were reported by traditional healers to be crushed in fresh and applied as a lotion on the lesions of patients of Abiato (Shererit). No significant correlation was observed between the age of traditional healers and the number of species reported and the indigenous knowledge transfer was found to be similar. More than one medicinal plant species were used more frequently than the use of a single species for remedy preparations. Plant parts used for remedy preparations showed significant difference with medicinal plant species abundance in the study area