356 research outputs found

    An Experiment and Detection Scheme for Cavity-based Cold Dark Matter Searches

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    A resonance detection scheme and some useful ideas for cavity-based searches of light cold dark matter particles (such as axions) are presented, as an effort to aid in the on-going endeavors in this direction as well as for future experiments, especially in possibly developing a table-top experiment. The scheme is based on our idea of a resonant detector, incorporating an integrated Tunnel Diode (TD) and a GaAs HEMT/HFET (High Electron Mobility Transistor/Heterogenous FET) transistor amplifier, weakly coupled to a cavity in a strong transverse magnetic field. The TD-amplifier combination is suggested as a sensitive and simple technique to facilitate resonance detection within the cavity while maintaining excellent noise performance, whereas our proposed Halbach magnet array could serve as a low-noise and permanent solution replacing the conventional electromagnets scheme. We present some preliminary test results which demonstrate resonance detection from simulated test signals in a small optimal axion mass range with superior Signal-to-Noise Ratios (SNR). Our suggested design also contains an overview of a simpler on-resonance dc signal read-out scheme replacing the complicated heterodyne readout. We believe that all these factors and our propositions could possibly improve or at least simplify the resonance detection and read-out in cavity-based DM particle detection searches (and other spectroscopy applications) and reduce the complications (and associated costs), in addition to reducing the electromagnetic interference and background.Comment: 22 pages, 7 figure

    Effect of Tillage Machinery Traffic on Soil Properties, Corn Root Development and Plant Growth

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    Rosana G. Moreira, Editor-in-Chief; Texas A&M UniversityThis is a paper from International Commission of Agricultural Engineering (CIGR, Commission Internationale du Genie Rural) E-Journal Volume 8 (2006): Effect of Tillage Machinery Traffic on Soil Properties, Corn Root Development and Plant Growth. Manuscript PM 06 026. Vol. VIII. December, 2006

    Pharmacists and telemedicine: an innovative model fulfilling Sustainable Development Goals (SDGs)

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    The lack of access to safe medicines and quality healthcare services in peri-urban and rural areas is a major challenge driving a health system to innovate new models of care. This commentary will discuss the implementation and impact of the “Guddi baji” tele-pharmacy model, a project piloted by doctHERs, one of Pakistan’s leading telemedicine organizations. This innovative model has described the reintegration of women into the workforce by leveraging technology to improve the level of primary health care services and contributes to safe medication practice in a remote area. Our intervention proposed the deployment of technology-enabled, female frontline health workers known as the Guddi baji (meaning The Good Sister) in a rural village. They serve as an “access point to health care” that is linked to a remotely located health care professional; a licensed doctor or a pharmacist within this model

    Switched reluctance motor design for electric vehicles based on harmonics and back EMF analysis

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    Permanent magnet synchronous motors are widely accepted in automotive applications. The high torque density, high rotational speed with maximum efficiency in electric vehicle applications is technically challenging for motor design. However, these machines are expensive and difficult to work at high-temperature harsh environment due to permanent magnets demagnetisation features. Alternatively, switched reluctance motors can provide similar output characteristics and a wider speed. Thus these are considered to be more fault tolerant and more reliable. This study proposes a 20 kW, three-phase switched reluctance motor and analyse its overall performance and harmonic contents. The study is conducted by optimising the slot filling factor, excitation voltage and switching sequence of an asymmetrical half bridge converter. A finite element model is used to predict the core and copper losses and other influencing parameters. Simulation results are presented and analysed the effectiveness of the proposed switched reluctance motor (SRM)

    A methodology for flexibility analysis of pipeline systems

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    Pipeline systems serve a crucial role in an effective transport of fluids to the designated location for medium to long span of distances. Owing to its paramount economic significance, pipeline design field have undergone extensive development over the past few years for enhancing the optimization and transport efficiency. This research paper attempts to propose a methodology for flexibility analysis of pipeline systems through employing contemporary computational tools and practices. A methodical procedure is developed, which involves modeling of the selected pipeline system in CAESAR II followed by the insertion of pipe supports and restraints. The specific location and selection of the inserted supports is based on the results derived from the displacement, stress, reaction, and nozzle analysis of the concerned pipeline system. Emphasis is laid on the compliance of the design features to the leading code of pipeline transportation systems for liquid and slurries, ASME B31.4. The discussed procedure and approach can be successfully adjusted for the analysis of various other types of pipeline system configuration. In addition to the provision of systematic flow in analysis, the method also improves efficient time-saving practices in the pipeline stress analysis

    Pharmacokinetics of Caffeic Acid from Methanol Seed Extract of Syzygium cumini L in Rats

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    Purpose: To describe caffeic acid-based pharmacokinetics of methanol extract of seed of Syzygium cumini L. in rats.Methods: A dose of the extract (500 mg, equivalent to 37.135 mg caffeic acid) was administered orally to 6 male Wister rats, weighing 200 ± 10 g. Blood samples (0.5 mL), collected from the tail vein at 0, 15, 30, 60, 120, 240 and 720 min, were processed and analyzed using high performance liquid chromatography and detected with florescent light detector (FLD).Results: Following the administration of the extract, caffeic acid achieved maximum plasma concentration (5.96 ± 0.49 Όg/mL) in 1.0 h which was also the time to achieve maximum concentration (Tmax). Mean resident time (MRT) and half-life (t1/2) were 4.092 ± 0.94 h and 0.14 ± 0.01 h, respectively.Conclusion: The results indicate that absorption of caffeic acid from the oral route is fast, but lower amounts are absorbed. The method developed for the extraction of caffeic acid from the plasma and HPLC determination may be useful in establishing phyto-bioequivalence between Syzygium cumini seed products.Keywords: Caffeic acid, Pharmacokinetics, Syzygium cumini, Phytobioequivalence, Absorptio

    Adsorption of paracetamol on activated charcoal in the presence of dextropropoxyphene hydrochloride, N-acetylcysteine and sorbitol

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    Paracetamol, an over the counter analgesic and antipyretic drug, causes hepatic and renal tubular necrosis at higher doses ingested accidentally, or intentionally. The situation worsens clinically upon the ingestion of product containing paracetamol and dextropropoxyphene. In paracetamol poisoning, activated charcoal is used to adsorb the drug from the gastrointestinal tract, sorbitol to remove charcoaldrug complexes and N-acetylcysteine to reduce the drug and its metabolites from systemic circulation. Activated charcoal being non-specific adsorbent may adsorb other chemical moieties from the intestine as well as antidotes. Therefore, the present study aimed to investigate the adsorption of paracetamol on activated charcoal in presence of dextropropoxyphene hydrochloride, N-acetylcysteine and sorbitol. Paracetamol was combined separately with dextropropoxyphene hydrochloride, N-acetylcysteine and sorbitol. These mixtures were combined with varying amounts of activated charcoal to evaluate the in vitro adsorption of paracetamol using Langmuir Isotherm. Paracetamol adsorption was 96.6 % at charcoal-drug ratio (6:1) while only 2 % higher in 8:1 and 2.9 % in 10:1. The binding constant (K2), maximum adsorption capacity per gram of activated charcoal for paracetamol alone and in presence of dextropropoxyphene hydrochloride, N-acetylcysteine and sorbitol was found to be 366, 339, 313 and 355 mg/g, respectively. The results of the present study indicate that except sorbitol other investigated substances significantly reduce the adsorption of paracetamol on activated charcoal, which may be compensated by increasing the concentration of activated charcoal.Colegio de Farmacéuticos de la Provincia de Buenos Aire

    Development of Paracetamol-Caffeine co-crystals to improve compressional, formulation and in-vivo performance

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    Paracetamol, a frequently used antipyretic and analgesic drug, has poor compression moldability owing to its low plasticity. In this study, new co-crystals of paracetamol (PCM) with caffeine (as a co-former) were prepared and delineated. Co-crystals exhibited improved compaction and mechanical behavior. A screening study was performed by utilizing a number of methods namely dry grinding, liquid assisted grinding (LAG), solvent evaporation (SE) and anti-solvent addition using various weight ratios of starting materials. LAG and SE were found successful in the screening study. Powders at 1:1 and 2:1 weight ratio of PCM/CAF by LAG and SE respectively resulted in the formation of co-crystals. Samples were characterized by PXRD, DSC and ATR-FTIR techniques. Compressional properties of PCM and developed co-crystals were analyzed by in-die heckle model. Mean yield pressure (Py), an inverse measure of plasticity, obtained from the heckle plots decreased significantly (p<0.05) for co-crystals than pure drug. Intrinsic dissolution profile of co-crystals showed up to 2.84 fold faster dissolution than PCM and physical mixtures in phosphate buffer pH 6.8 at 37 oC. In addition co-crystals formulated into tablets by direct compression method showed better mechanical properties like hardness and tensile strength. In vitro dissolution studies on tablets also showed enhanced dissolution profiles (~90- 97%) in comparison to the tablets of PCM prepared by direct compression (~55%) and wet granulation (~85%) methods. In a single dose sheep model study co-crystals showed up to two fold increase in AUC and Cmax. A significant (p < 0.05) decrease in clearance as compared to pure drug was also recorded. In conclusion new co-crystals of PCM were successfully prepared with improved tabletability in-vitro and in-vivo profile. Enhancement in AUC and Cmax of PCM by co-crystallisation might suggest the dose reduction and avoidance of side effects

    The prevalence of HBV infection in the cohort of IDPs of war against terrorism in Malakand Division of Northern Pakistan

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    <p>Abstract</p> <p>Background</p> <p>Hepatitis B is an important public health problem in the Pakistani population and is the major cause of chronic hepatitis, cirrhosis, fibrosis and hepatocellular carcinoma. High prevalence of HBV infections has been observed especially in areas of low economic status. In spite of effective immunization programs, no significant change has been observed in the epidemiology of HBV in the rural areas of Pakistan (~67.5% of the total population) mainly due to lack of interest from government authorities and poor hygienic measures. The current study was aimed at estimating the prevalence and risk factors associated with HBV infection within internally displaced persons (IDPs) due to war against terrorism in the Malakand Division of Northern Pakistan.</p> <p>Methods</p> <p>Blood samples from 950 IDPs suspected with HBV infection (including both males and females) were collected and processed with commercial ELISA kits for HBsAg, Anti HBs, HBeAg, Anti HBe antibodies. The samples positive by ELISA were confirmed for HBV DNA by real-time PCR analysis.</p> <p>Results</p> <p>The overall prevalence of HBV observed was 21.05% of which 78.5% were males and 21.5% were females. Most confirmed HBV patients belong to the Malakand and Dir (lower) district. High-risk of infection was found in the older subjects 29.13% (46-60 years), while a lower incidence (11.97%) was observed in children aged <15 years. Lack of awareness, socioecomic conditions, sexual activities and sharing of razor blades, syringes and tattooing needles were the most common risk factors of HBV infection observed during the cohort of patients.</p> <p>Conclusion</p> <p>The present study, revealed for the first time a high degree of prevalence of HBV infection in rural areas of Northern Pakistan. The noticed prevalence is gender- and age-dependent that might be due to their high exposures to the common risk factors. To avoid the transmission of HBV infection proper awareness about the possible risk factors and extension of immunization to the rural areas are recommended.</p

    Automatic Extraction of Nuclei Centroids of Mouse Embryonic Cells from Fluorescence Microscopy Images

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    Accurate identification of cell nuclei and their tracking using three dimensional (3D) microscopic images is a demanding task in many biological studies. Manual identification of nuclei centroids from images is an error-prone task, sometimes impossible to accomplish due to low contrast and the presence of noise. Nonetheless, only a few methods are available for 3D bioimaging applications, which sharply contrast with 2D analysis, where many methods already exist. In addition, most methods essentially adopt segmentation for which a reliable solution is still unknown, especially for 3D bio-images having juxtaposed cells. In this work, we propose a new method that can directly extract nuclei centroids from fluorescence microscopy images. This method involves three steps: (i) Pre-processing, (ii) Local enhancement, and (iii) Centroid extraction. The first step includes two variations: first variation (Variant-1) uses the whole 3D pre-processed image, whereas the second one (Variant-2) modifies the preprocessed image to the candidate regions or the candidate hybrid image for further processing. At the second step, a multiscale cube filtering is employed in order to locally enhance the pre-processed image. Centroid extraction in the third step consists of three stages. In Stage-1, we compute a local characteristic ratio at every voxel and extract local maxima regions as candidate centroids using a ratio threshold. Stage-2 processing removes spurious centroids from Stage-1 results by analyzing shapes of intensity profiles from the enhanced image. An iterative procedure based on the nearest neighborhood principle is then proposed to combine if there are fragmented nuclei. Both qualitative and quantitative analyses on a set of 100 images of 3D mouse embryo are performed. Investigations reveal a promising achievement of the technique presented in terms of average sensitivity and precision (i.e., 88.04% and 91.30% for Variant-1; 86.19% and 95.00% for Variant-2), when compared with an existing method (86.06% and 90.11%), originally developed for analyzing C. elegans images
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