2,857 research outputs found

    Implications of time-dependent molecular chemistry in metal-poor dwarf stars

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    Binary molecules such as CO, OH, CH, CN, and C2_2 are often used as abundance indicators in stars. These species are usually assumed to be formed in chemical equilibrium. The time-dependent effects of hydrodynamics can affect the formation and dissociation of these species and may lead to deviations from chemical equilibrium. We aim to model departures from chemical equilibrium in dwarf stellar atmospheres by considering time-dependent chemical kinetics alongside hydrodynamics and radiation transfer. We examine the effects of a decreasing metallicity and an altered C/O ratio on the chemistry when compared to the equilibrium state. We used the radiation-(magneto)hydrodynamics code CO5BOLD, and its own chemical solver to solve for the chemistry of 15 species and 83 reactions. The species were treated as passive tracers and were advected by the velocity field. The steady-state chemistry was also computed to isolate the effects of hydrodynamics. In most of the photospheres in the models we present, the mean deviations are smaller than 0.20.2 dex, and they generally appear above logτ=2\log{\tau} = -2. The deviations increase with height because the chemical timescales become longer with decreasing density and temperature. A reduced metallicity similarly results in longer chemical timescales and in a reduction in yield that is proportional to the drop in metallicity; a decrease by a factor 100100 in metallicity loosely corresponds to an increase by factor 100100 in chemical timescales. As both CH and OH are formed along reaction pathways to CO, the C/O ratio means that the more abundant element gives faster timescales to the constituent molecular species. Overall, the carbon enhancement phenomenon seen in very metal-poor stars is not a result of an improper treatment of molecular chemistry for stars up to a metallicity as low as [Fe/H] = 3.0-3.0.Comment: 29 page

    Accurate estimations of circumstellar and interstellar lines of quadruply ionized vanadium using the coupled cluster approach

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    Accurate {\it ab initio} calculations have been carried out to study the valence electron removal energies and oscillator strengths of astrophysically important electromagnetic transitions of quadruply ionized vanadium, V4+V^{4+}. Many important electron correlations are considered to all-orders using the relativistic coupled-cluster theory. Calculated ionization potentials and fine structure splittings are compared with the experimental values, wherever available. To our knowledge, oscillator strengths of electric dipole transitions are predicted for the first time for most of the transitions. The transitions span in the range of ultraviolet, visible and near infrared regions and are important for astrophysical observations.Comment: Submitted in Astrophysical

    Biomedical Waste Management – A Review

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    Bio-medical waste is generated mainly by health care establishments. The management of Bio-medical waste is still infant all across the world. It consists of Bio-medical waste as well as chemical waste with a portion of solid waste. This is a review paper which is prepared from the surveys of various research papers on improper biomedical waste. This research article is to survey the practice of biomedical waste such as collection, storage, transportation and disposal along with the amount of generated biomedical waste in various hospitals. Biomedical waste management is one of the biggest challenges of the present day times. It has a direct impact on the health of the citizen of that city. It is hazardous in nature. It’s safe and proper disposal is extremely important. As in many developing countries the generation of biomedical waste has increased significantly over the last few decades, management of this kind of waste continues to be a major challenge. Biomedical waste is generated in hospitals, research institutions, health care teaching institutes, clinics, laboratories, blood banks, animal houses and veterinary institutes. For proper management of bio-medical waste the Ministry of Environment and Forests has promulgated the Bio-Medical Waste (Management and Handling) Rules, 1998. Purpose of study was to highlight certain aspects of hospital waste management status. This paper will sensitize the reader about the impacts of improper waste management. Proper handling, treatment and disposal of the biomedical waste material are most important issue for the health of the human beings. The inadequate knowledge about the proper handling of biomedical waste can be dangerous to the health of common man as well as of health care personnel. This review discusses about various types of waste, its hazards and management

    The effect of Kushamoola in the management of Rakthapradara - A Clinical Study

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    The word Artava denotes two meanings one of them is Antah Pushpa and another one is Bahir Pushpa. Both Antah and Bahir Pushpa are interrelated. Bahir Pushpa is outward manifestation of appropriate work of Antah Pushpa which is necessary for conception. Here, the present study deal with Bahir Pushpa that is menstrual blood. As heavy menstrual bleeding (Raktapradara) is a debilitating disorder, the woman requires rapid, safe and effective treatment. Ayurvedic texts have described a variety of treatment options in the management of “Rakta Pradara”. Due to alteration of food habits and changing life styles complaint of the excessive and irregular uterine bleeding is increasing day by day. Excessive bleeding is the most common cause of anemia and dysmenorrhoea. High rate of complication of hysterectomy as well as it is not suitable for younger patients and who wish to conceive further. Due to limitation of medical therapy as well surgical therapy of modern science, it becomes the necessity of the time to find out harmless therapy to manage the condition.These are the factors why the topic is being selected for the present study

    Influence of CuO on temperature dependent H2S gas sensing performance of ZrO2 thick film resistor

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    Popular   screen printed   ZrO2 thick film resistor was formulated for characterization. These films were surface modified by dipping them in 0.1 M CuCl2 aqueous solution for the time intervals of 5,10,20, 30 and 40  minutes. Surface morphology and   elemental composition were studied using scanning electron microscopy coupled with energy dispersive   spectroscopy. It was observed that Cu converted into CuO at 200oC during sintering of the films and this p-type oxide plays role with n- type ZrO2 for H2S gas sensing. X-diffraction confirmed the polycrystalline nature of pure ZrO2 powder and influence of copper on film surface disappear the polymorphs and only strong crystalline peak was observed. It was good indication for gas sensing. Bandwidth reduction was observed   by characterizing film with UV spectroscopy techniques. Pure ZrO2 film sample was shown wide bandwidth than sintered and modified film.  The gas sensing performances of various gases were tested previously and it is reported for Ammonia except oxygen. Negative temperature coefficient of the CuO activated film shift response to H2S gas at elevated temperature between 300oC to 450 oC.  Maximum Gas sensing response was observed at operating temperature 450oc for 100ppm concentration. It was observed temperature, thickness and concentration dependent. Quick response time and fast recovery were recorded. Keywords: thick film , CuO activated, H2S gas sensor, bandwidth reduction, quick response and fast recover

    A genome-wide association study suggests an association of Chr8p21.3 (GFRA2) with diabetic neuropathic pain

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    BACKGROUND: Neuropathic pain, caused by a lesion or a disease affecting the somatosensory system, is one of the most common complications in diabetic patients. The purpose of this study is to identify genetic factors contributing to this type of pain in a general diabetic population. METHOD: We accessed the Genetics of Diabetes Audit and Research Tayside (GoDARTS) datasets that contain prescription information and monofilament test results for 9439 diabetic patients, among which 6927 diabetic individuals were genotyped by Affymetrix SNP6.0 or Illumina OmniExpress chips. Cases of neuropathic pain were defined as diabetic patients with a prescription history of at least one of five drugs specifically indicated for the treatment of neuropathic pain and in whom monofilament test result was positive for sensory neuropathy in at least one foot. Controls were individuals who did not have a record of receiving any opioid analgesics. Imputation of non‐genotyped SNPs was performed by IMPUTE2, with reference files from 1000 Genomes Phase I datasets. RESULTS: After data cleaning and relevant exclusions, imputed genotypes of 572 diabetic neuropathic pain cases and 2491 diabetic controls were used in the Fisher's exact test. We identified a cluster in the Chr8p21.3, next to GFRA2 with a lowest p‐value of 1.77 × 10(−7) at rs17428041. The narrow‐sense heritability of this phenotype was 11.00%. CONCLUSION: This genome‐wide association study on diabetic neuropathic pain suggests new evidence for the involvement of variants near GFRA2 with the disorder, which needs to be verified in an independent cohort and at the molecular level

    RUELLIA TUBEROSA LINN. ACTS AS ANTI-FERTILITY AGENT THAT REDUCES SPERM COUNT, MOTILITY AND VIABILITY IN MALE SWISS ALBINO MICE (MUS-MUSCULUS)

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    Objective: Fertility control is an issue of global public health. Many of the contraceptives available today have one or the other side effects. Many plants and plant products are suggested as contraceptives in folk and traditional systems of medicine. However, that are least exploited in this regard. In the present investigation, root powder of Ruellia tuberosa was studied for its effect on male reproduction in mice.Methods: The Swiss albino mice, Mus musculus of age three months were grouped into four, i)control group, fed on standard pellet, ii)experimental groups I and II received root powder of Ruellia tuberosa 50 mg/mouse/days for 15 d and 30 d respectively in the pellets, iii)positive control groups I and II received cotton seed oil 25 µl/mouse/day for 15 and 30 d and iv)recovery group received Ruellia tuberosa (50 mg/mouse/days) containing pellets for 15 d and later standard pellet for 15 d. Cauda epididymis sperm suspension was analyzed for sperm count, motility and viability.Results: There was a highly significant decrease in sperm count, motility and viability (p<0.001) in experimental groups I and II and positive control groups I and II. The sperm count was reduced to 19.24±1.74 million/ml and 15.97±5.61 million/ml as compared to sperm count in control group (55.12±4.63 million/ml) in experimental groups. Partial reversal of the effect was noticed in a recovery group.Conclusion: The results suggest that Ruellia tuberosa can be a potent member of reversible oral male contraceptives

    Adherence to ARRIVE guidelines in animal research articles published in a National and International Pharmacology Journal

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    Background: This study compares the adherence to Animal Research: Reporting of In Vivo Experiments (ARRIVE) guidelines in an Indian (IJP: Indian Journal of Pharmacology) and International journal (JPET: Journal of Pharmacology and Experimental Therapeutics).Methods: All original animal studies published in IJP and JPET between January 2014 and September 2015 were downloaded manually and 100 articles were randomly chosen from each journal and analyzed using the ARRIVE guidelines checklist and checked for adherence.Results: Most articles indicated the ethical statement (IJP- 96%, JPET- 98%). Steps taken to minimize effects of subjective bias in the study design were not mentioned in more than half the articles (IJP-50%, JPET-37%). Details of experimental animals were not adequately reported (IJP- 79%, JPET-68%). Details of animal housing (IJP-20%, JPET-39%) and husbandry (IJP-59%, JPET-51%) were poorly reported. Explanation of sample size calculation was mentioned in 2% and 1% articles in IJP and JPET. Statistical methods were well explained, yet the methods used to assess whether the data met the assumptions of the statistical approach was poorly reported.Conclusions: The present study demonstrates relatively suboptimal reporting standards in animal studies published in IJP and JPET. Adherence to ARRIVE guidelines can be improved

    Identification of transcriptional regulatory networks specific to pilocytic astrocytoma.

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    BackgroundPilocytic Astrocytomas (PAs) are common low-grade central nervous system malignancies for which few recurrent and specific genetic alterations have been identified. In an effort to better understand the molecular biology underlying the pathogenesis of these pediatric brain tumors, we performed higher-order transcriptional network analysis of a large gene expression dataset to identify gene regulatory pathways that are specific to this tumor type, relative to other, more aggressive glial or histologically distinct brain tumours.MethodsRNA derived from frozen human PA tumours was subjected to microarray-based gene expression profiling, using Affymetrix U133Plus2 GeneChip microarrays. This data set was compared to similar data sets previously generated from non-malignant human brain tissue and other brain tumour types, after appropriate normalization.ResultsIn this study, we examined gene expression in 66 PA tumors compared to 15 non-malignant cortical brain tissues, and identified 792 genes that demonstrated consistent differential expression between independent sets of PA and non-malignant specimens. From this entire 792 gene set, we used the previously described PAP tool to assemble a core transcriptional regulatory network composed of 6 transcription factor genes (TFs) and 24 target genes, for a total of 55 interactions. A similar analysis of oligodendroglioma and glioblastoma multiforme (GBM) gene expression data sets identified distinct, but overlapping, networks. Most importantly, comparison of each of the brain tumor type-specific networks revealed a network unique to PA that included repressed expression of ONECUT2, a gene frequently methylated in other tumor types, and 13 other uniquely predicted TF-gene interactions.ConclusionsThese results suggest specific transcriptional pathways that may operate to create the unique molecular phenotype of PA and thus opportunities for corresponding targeted therapeutic intervention. Moreover, this study also demonstrates how integration of gene expression data with TF-gene and TF-TF interaction data is a powerful approach to generating testable hypotheses to better understand cell-type specific genetic programs relevant to cancer

    Using single quantum states as spin filters to study spin polarization in ferromagnets

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    By measuring electron tunneling between a ferromagnet and individual energy levels in an aluminum quantum dot, we show how spin-resolved quantum states can be used as filters to determine spin-dependent tunneling rates. We also observe magnetic-field-dependent shifts in the magnet's electrochemical potential relative to the dot's energy levels. The shifts vary between samples and are generally smaller than expected from the magnet's spin-polarized density of states. We suggest that they are affected by field-dependent charge redistribution at the magnetic interface.Comment: 4 pages, 1 color figur
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