Electron imaging of dielectrics under simultaneous electron-ion irradiation

We demonstrate that if charging caused by electron irradiation of an insulator is controlled by a defocused flux of soft-landing positive ions, secondary electron (SE) images can contain contrast due to lateral variations in (i) changes in the SE yield caused by subsurface trapped charge and (ii) the SE-ion recombination rate. Both contrast mechanisms can provide information on microscopic variations in dielectric properties. We present a model of SE contrast formation that accounts for localized charging and the effects of gas ions on the SE emission process, emitted electrons above the sample surface, and subsurface trapped charge. The model explains the ion flux dependence of charge-induced SE contrast, an increase in the sensitivity to surface contrast observed in SE images of charged dielectrics, and yields procedures for identification of contrast produced by localized sample charging. © 2002 American Institute of Physics. © 2002 American Institute of Physics

Overview of pulsed electric field (pef) preservation on food products

The rise in consumer demand for nutritious food options combined with a desire for a more natural taste has prompted the creation of novel gentle food preservation processes as alternatives to traditional methods like heat treatment. New Methods like high hydrostatic pressure and pulsed electric fields (PEFs), have emerged as no thermal pasteurization methods. These methods aim to effectively reduce microbial content while maintaining the quality of the food product. Pulsed electric field processing is particularly suitable for decontaminating heat-sensitive foods. Furthermore, it presents no environmental risks and has shown no indications of toxicity [1]

Spirulina: nutritional and therapeutic review

The current environmental conditions deteriorations, mental and physical stress, changes in the diet have been serious risk factors for the humans, increased the death rate and civilization diseases. These are the obvious reasons why new progressive trends are being extensively developed in modern medicine, pharmacology and biotechnology and more effective harmless medicaments are being sought for to treat and prevent various diseases. One of the trends in biotechnology is associated with Blue green microalgae Spirulina platensis which have been widely employed as food and feed additives in agriculture, food industry, pharmaceuticals, perfume making, medicine and science [1]

Electric fields produced by electron irradiation of insulators in a low vacuum environment

We report on the properties of electric fields generated as a result of electron irradiation of dielectrics in a low vacuum scanning electron microscope. Individual field components produced by (i) ionized gas molecules located outside the sample surface and (ii) subsurface trapped charge were detected by measurements of changes in (i) primary electron landing energy and (ii) secondary electron (SE) emission current, respectively. The results provide experimental evidence for a recently proposed model of field-enhanced SE emission from electron irradiated insulators in a low vacuum environment [Toth et al., J. Appl. Phys. 91, 4479 (2002)]. Errors introduced into x-ray microanalysis by the electric fields generated by ionized gas molecules can be alleviated by minimizing the steady state ion concentration by the provision of efficient ion neutralization routes. It is demonstrated how this can be achieved using simple sample-electrode geometries. © 2002 American Institute of Physics. © 2002 American Institute of Physics

Approximation Algorithms for Generalized MST and TSP in Grid Clusters

We consider a special case of the generalized minimum spanning tree problem (GMST) and the generalized travelling salesman problem (GTSP) where we are given a set of points inside the integer grid (in Euclidean plane) where each grid cell is $1 \times 1$. In the MST version of the problem, the goal is to find a minimum tree that contains exactly one point from each non-empty grid cell (cluster). Similarly, in the TSP version of the problem, the goal is to find a minimum weight cycle containing one point from each non-empty grid cell. We give a $(1+4\sqrt{2}+\epsilon)$ and $(1.5+8\sqrt{2}+\epsilon)$-approximation algorithm for these two problems in the described setting, respectively. Our motivation is based on the problem posed in [7] for a constant approximation algorithm. The authors designed a PTAS for the more special case of the GMST where non-empty cells are connected end dense enough. However, their algorithm heavily relies on this connectivity restriction and is unpractical. Our results develop the topic further

Potential of Photovoltaics and Energy Storage to Address Lack of Electricity Access

Lack of electricity access is widespread in the developing world and associated with increased mortality, reduced educational levels, and economic and social disadvantages, especially among women. The 2030 Agenda for Sustainable Development has emphasized securing access to affordable, reliable, and sustainable energy for all. For climatological and health reasons, particular attention has been focused on expanding the use of renewables for electricity production. In particular, photovoltaics, coupled to energy storage, is an attractive option for dispatchable electricity production, but the degree to which they can be used to address global lack of electricity access, and associated costs, merits more attention. This study presents a global geospatial analysis to identify areas suitable for production of dispatchable electricity using photovoltaics and energy storage. Analysis considers land use restrictions, 25 years of historical hourly solar irradiance, seasonal demand curves, population, and visible nighttime light (as a measure of electrification). We show that nearly all the population identified without electricity access (approx. 1.1 billion people) could get access to Tier 5 level electricity in the Sustainable Energy for All initiative framework using photovoltaics and battery storage coupled systems. Under most cost scenarios analyzed, around 90 percent of this population could be served for a lifetime cost of electricity (LCOE) of 0.20 dollars per kWhe or less at current system costs

Original Article

Abstract Objective: The objective of this study is to evaluate the clinical profile and drug response in typhoid fever. Methods: This is a retrospective analysis of paediatric patients suffering from typhoid fever who were admitted at Kathmandu Medical College Teaching Hospital, Sinamangal during the period of two years and nine months. Results: Total numbers of 100 cases of typhoid were studied. Diagnosis of Typhoid fever was based on clinical features, Widal test and blood culture. The sensitivity pattern of drugs in blood culture was recorded. The mode of presentation, treatment history, laboratory investigations reports, antibiotics administered and response to therapy were recorded. Conclusion: Quinolone is still the highly sensitive drug and most widely used for Salmonella typhi. Because of the indiscriminate use of these drugs, resistant to ciprofloxacin has been quite high and the duration of the defeverscence period has also been prolonged. But Ofloxacin is still showed highly effective and widely used with good response

A study of therapeutic effect of the growth of children with hypothyroidism

Abstract Objectives: This study was done to see the therapeutic effect of the growth of children who was diagnosed as hypothyroidism. Methods: Thirty-four children with primary hypothyroidism were included in this study. Height, weight and head circumference were measured at initial diagnosis and at every follow up visit. Thyroid function was done. The value was interpreted as abnormal if the range was above or below the normal (T3=70-200 u/L, T4=4-13 u/L, TSH=0.3-6 u/L). X-ray to see the bone age for the chronological age was performed. The value was interpreted as abnormal if the ossification center for the chronological age in inappropriate. Treatment was started with Eltroxine from the day of diagnosis. Dose was adjusted according to the response to the medicine. T3, T4 and TSH level was taken as the guideline to adjust the dose of the drug. X-ray was considered in the follow up where it was indicated. Result: Marked improvement in the anthropometry was seen in comparison to the initial assessment which was well correlated with the normalization of the TSH level and the x-ray of the bone. Conclusion: Serial follow up of these patients was necessary in order to assess the growth in height, weight and head circumference along with the repeated thyroid function to correlate the response of the drug

Minimal Model Holography for SO(2N)

A duality between the large N 't Hooft limit of the WD_N minimal model CFTs and a higher spin gravity theory on AdS3 is proposed. The gravity theory has massless spin fields of all even spins s=2,4,6,..., as well as two real scalar fields whose mass is determined by the 't Hooft parameter of the CFT. We show that, to leading order in the large N limit, the 1-loop partition function of the higher spin theory matches precisely with the CFT partition function.Comment: 21 pages, LaTe