Luminescence from Si nanocrystals in silica deposited by helicon activated reactive evaporation

An alternative method is investigated for the preparation of Si-rich SiO₂films used for the fabrication of light-emitting Si nanocrystalstructures. The technique, helicon-activated reactive evaporation (HARE), combines e-beam evaporation of silicon with plasma activation of a reactive argon–oxygen atmosphere, and has the advantage of being able to produce thick, H-free films suitable for planar photonic device applications. The nanocrystal-rich films were formed by annealing as-deposited films at 1100 °C for 1 h. Room temperature photoluminescence was then measured and compared with that from ion-implanted samples annealed under similar conditions. The HARE-deposited films exhibited strong visible luminescence for a range of excess Si concentrations, demonstrating their potential for the manufacture of such materials. The films also exhibited a concentration dependence comparable to that of ion-implanted samples: the luminescence intensity initially increased with excess Si concentration up to a maximum before decreasing with increasing concentration thereafter. The cause of the decrease at higher concentrations is briefly discussed

Multipatch Stochastic Epidemic Model for the Dynamics of a Tick-Borne Disease

Spatial heterogeneity and migration of hosts and ticks have an impact on the spread, extinction and persistence of tick-borne diseases. In this paper, we investigate the impact of between-patch migration of white-tailed deer and lone star ticks on the dynamics of a tick-borne disease with regard to disease extinction and persistence using a system of Itô stochastic differential equations model. It is shown that the disease-free equilibrium exists and is unique. The general formula for computing the basic reproduction number for all patches is derived. We show that for patches in isolation, the basic reproduction number is equal to the largest patch reproduction number and for connected patches it lies between the minimum and maximum of the patch reproduction numbers. Numerical simulations for a two-patch deterministic and stochastic differential equation models are performed to illustrate the dynamics of the disease for varying migration rates. Our results show that the probability of eliminating or minimizing the disease in both patches is high when there is no migration unlike when it is present. The results imply that the probability of disease extinction can be increased if deer and tick movement are controlled or even prohibited especially when there is an outbreak in one or both patches since movement can introduce a disease in an area that was initially disease-free. Thus, screening of infectives in protected areas such as deer farms, private game parks or reserves, etc. before they migrate to other areas can be one of the intervention strategies for controlling and preventing disease spread

Quantum corrections for pion correlations involving resonance decays

A method is presented to include quantum corrections into the calculation of two-pion correlations for the case where particles originate from resonance decays. The technique uses classical information regarding the space-time points at which resonances are created. By evaluating a simple thermal model, the method is compared to semiclassical techniques that assume exponential decaying resonances moving along classical trajectories. Significant improvements are noted when the resonance widths are broad as compared to the temperature.Comment: 9 pages, 4 figure

Defining the Risk of Zika and Chikungunya Virus Transmission in Human Population Centers of the Eastern United States

The recent spread of mosquito-transmitted viruses and associated disease to the Americas motivates a new, data-driven evaluation of risk in temperate population centers. Temperate regions are generally expected to pose low risk for significant mosquito-borne disease; however, the spread of the Asian tiger mosquito (Aedes albopictus) across densely populated urban areas has established a new landscape of risk. We use a model informed by field data to assess the conditions likely to facilitate local transmission of chikungunya and Zika viruses from an infected traveler to Ae. albopictus and then to other humans in USA cities with variable human densities and seasonality. Mosquito-borne disease occurs when specific combinations of conditions maximize virus-to-mosquito and mosquito-to-human contact rates. We develop a mathematical model that captures the epidemiology and is informed by current data on vector ecology from urban sites. The model demonstrates that under specific but realistic conditions, fifty-percent of introductions by infectious travelers to a high human, high mosquito density city could initiate local transmission and 10% of the introductions could result in 100 or more people infected. Despite the propensity for Ae. albopictus to bite non-human vertebrates, we also demonstrate that local virus transmission and human outbreaks may occur when vectors feed from humans even just 40% of the time. Inclusion of human behavioral changes and mitigations were not incorporated into the models and would likely reduce predicted infections. This work demonstrates how a conditional series of non-average events can result in local arbovirus transmission and outbreaks of human disease, even in temperate cities

Effect of melatonin on oxidative stress markers in patients with alopecia areata

Alopecia areata is an autoimmune, nonscarring, multifocal disorder of hair growth characterized by circular bald areas, which occur on any hair bearing site of the body. The exact cause of alopecia areata is unknown. Recent study reported a potential role of oxygen free radicals (OFR) in pathogenesis of alopecia areata. This clinical study was designed to evaluate the antioxidant effect of melatonin (3 mg every other day ) in patients with alopecia areata. This study revealed that two month treatment with melatonin antioxidant led to a decrease in the basal level of malondialdehyde (MDA) an index of lipid peroxidation, an increase in basal glutathione (GSH) content a major endogenous antioxidant in both plasma and erythrocytes and an increase in plasma total antioxidant status( TAS ) . The most important point is the clinical significance of antioxidants in improving the hair growth response of patients with alopecia areata. This may be due to direct and/or indirect effect of melatonin on immune system. The direct effect may be through its immunoenhancing / immunostimulatory properties of melatonin.The indirect effect is the scavenging activity of this antioxidant, which in turn decrease damaging effect of oxygen free radicals (OFR) and utilization of GSH in neutralizing phagocytes- induced free radicals. So replenishment of GSH within natural killer (immune) cells strengthens the immune system and increases the rate of hair growth

General practitioners' views on genomics, practice and education A qualitative interview study

Background and objective Genomics is moving rapidly into mainstream medicine through clinical genomic testing and consumer-initiated online DNA testing. The aim of this study was to identify Australian general practitioners' (GPs‘) views on genomics, impact on practice and educational needs to inform continuing education. Methods Semi-structured interviews were conducted, with constant comparative inductive analysis and governance from a national taskforce. Results Twenty-eight GPs (43% female) were interviewed; 71% worked in a metropolitan workplace. Most initially reported little experience with genetic/genomic tests but, when prompted, recognised encountering genomics, mainly non-invasive prenatal and single-gene tests. Many GPs referred patients for cancer screening to genetic services or specialists. GPs reported needing continuing education and resources, with preferences underpinned by relevance to practice. Discussion GPs are integrating genomic testing into care, mainly through prenatal screening, and anticipate further impact. They want diverse and context-dependent education but are unaware of some available resources, such as The Royal Australian College of General Practitioners’ Genomics in general practice guideline

Ensuring Best Practice in Genomic Education and Evaluation: A Program Logic Approach

© Copyright © 2019 Nisselle, Martyn, Jordan, Kaunein, McEwen, Patel, Terrill, Bishop, Metcalfe and Gaff. Targeted genomic education and training of professionals have been identified as core components of strategies and implementation plans for the use of genomics in health care systems. Education needs to be effective and support the sustained and appropriate use of genomics in health care. Evaluation of education programs to identify effectiveness is challenging. Furthermore, those responsible for development and delivery are not necessarily trained in education and/or evaluation. Program logic models have been used to support the development and evaluation of education programs by articulating a logical explanation as to how a program intends to produce the desired outcomes. These are highly relevant to genomic education programs, but do not appear to have been widely used to date. To assist those developing and evaluating genomic education programs, and as a first step towards enabling identification of effective genomic education approaches, we developed a consensus program logic model for genomic education. We drew on existing literature and a co-design process with 24 international genomic education and evaluation experts to develop the model. The general applicability of the model to the development of programs was tested by program convenors across four diverse settings. Conveners reported on the utility and relevance of the logic model across development, delivery and evaluation. As a whole, their feedback suggests that the model is flexible and adaptive across university award programs, competency development and continuing professional development activities. We discuss this program logic model as a potential best practice mechanism for developing genomic education, and to support development of an evaluation framework and consistent standards to evaluate and report genomic education program outcomes and impacts

Effect of nutrient antioxidants on oxidative stress indicators in patients with alopecia areata

People with alopecia areata lose their scalp hair in smooth round patches typically causing bald spots about an inch (2cm) across. Recently Al-Jaff et al demonstrate the association of free radicals in the pathogenesis of alopecia areata, and the role of nutrient antioxidants in protecting the immune system from the damaging effect of these radicals.Any imbalances between free radical production and antioxidant deficiency can result in an injury. This clinical study designed to study the role of nutrient antioxidants in protecting the body from damaging effect of radicals and the effect of two month treatment with antioxidants (vitamin A, E, &C) on oxidative stress variable levels and their effect on rate of hair growth in patients with alopecia areata. Treatment with antioxidants significantly elevated body antioxidant defenses component levels, increased Zn levels and decreased Cu levels and corrected the inbalance in these trace metals metabolism in alopecia after 1and 2 months of treatment compared to pretreatment values. The most important point is the clinical significance of antioxidants in improving the hair response of patients with alopecia areata; this may be due to an inhibition of oxidative stress associated with the state of the disease

Invasion of Two Tick-borne Diseases Across New England: Harnessing Human Surveillance Data to Capture Underlying Ecological Invasion Processes

Modelling the spatial spread of vector-borne zoonotic pathogens maintained in enzootic transmission cycles remains a major challenge. The best available spatio-temporal data on pathogen spread often take the form of human disease surveillance data. By applying a classic ecological approach-occupancy modelling-to an epidemiological question of disease spread, we used surveillance data to examine the latent ecological invasion of tick-borne pathogens. Over the last half-century, previously undescribed tick-borne pathogens including the agents of Lyme disease and human babesiosis have rapidly spread across the northeast United States. Despite their epidemiological importance, the mechanisms of tick-borne pathogen invasion and drivers underlying the distinct invasion trajectories of the co-vectored pathogens remain unresolved. Our approach allowed us to estimate the unobserved ecological processes underlying pathogen spread while accounting for imperfect detection of human cases. Our model predicts that tick-borne diseases spread in a diffusion-like manner with occasional long-distance dispersal and that babesiosis spread exhibits strong dependence on Lyme disease

Optimized Discretization of Sources Imaged in Heavy-Ion Reactions

We develop the new method of optimized discretization for imaging the relative source from two particle correlation functions. In this method, the source resolution depends on the relative particle separation and is adjusted to available data and their errors. We test the method by restoring assumed pp sources and then apply the method to pp and IMF data. In reactions below 100 MeV/nucleon, significant portions of the sources extend to large distances (r > 20 fm). The results from the imaging show the inadequacy of common Gaussian source-parametrizations. We establish a simple relation between the height of the pp correlation function and the source value at short distances, and between the height and the proton freeze-out phase-space density.Comment: 36 pages (inc. 9 figures), RevTeX, uses epsf.sty. Submitted to Phys. Rev.