826 research outputs found

    Study of Optical, Electrical and Photocatalysis Properties of SrMnO3 Synthesized by Solid-State Reaction

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    SrMnO3 was prepared by solid-state reaction method to obtain powder then thin films by a thermal evaporation method. XRD diffraction, Optical and electrical properties were investigated. Photocatalysis process was implemented as an interesting application of SrMnO3. XRD diffraction results were used to study the compound structure and to calculate some other parameters such as crystallite size, D, microstrain, e, and dislocation density, d. XRD results revealed that SrMnO3 has a polycrystalline structure such as hexagonal structure for SrMnO3 phase and tetragonal structure for MnO2 phase. The optical energy band for the powder and thin film were equal to 2.28 eV and 2.92 eV respectively, which candidates this compound to be a solar cell transparent window, especially for deposited thin films. The electrical resistivity behaved as semiconductor-like where it decreases with the temperature with electrical activation energy equal 0.960 eV when heating and 0.663 eV when cooling. The result of the Methylene blue absorption showed that the SrMnO3 powder does work very well as a Photocatalyst. The efficiency of the powder of SrMnO3 as a Photocatalyst increases with the illumination time and its best value is about 56% at 120 min

    Study of Optical, Electrical and Photocatalysis Properties of SrMnO3 Synthesized by Solid-State Reaction

    Get PDF
    SrMnO3 was prepared by solid-state reaction method to obtain powder then thin films by a thermal evaporation method. XRD diffraction, Optical and electrical properties were investigated. Photocatalysis process was implemented as an interesting application of SrMnO3. XRD diffraction results were used to study the compound structure and to calculate some other parameters such as crystallite size, D, microstrain, e, and dislocation density, d. XRD results revealed that SrMnO3 has a polycrystalline structure such as hexagonal structure for SrMnO3 phase and tetragonal structure for MnO2 phase. The optical energy band for the powder and thin film were equal to 2.28 eV and 2.92 eV respectively, which candidates this compound to be a solar cell transparent window, especially for deposited thin films. The electrical resistivity behaved as semiconductor-like where it decreases with the temperature with electrical activation energy equal 0.960 eV when heating and 0.663 eV when cooling. The result of the Methylene blue absorption showed that the SrMnO3 powder does work very well as a Photocatalyst. The efficiency of the powder of SrMnO3 as a Photocatalyst increases with the illumination time and its best value is about 56% at 120 min

    CHEMICAL INVESTIGATION OF BAUHINIA VAHLII WIGHT AND ARNOTT LEAVES GROWN IN EGYPT

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    Objective: Plants of genus Bauhinia are famous for their rich flavonoid content. Several phytochemical and biological investigations affirmed the role of flavonoids in the different biological impacts exerted by Bauhinia plants. The present study aims to investigate the major phytoconstituents of the leaves of B. vahlii Wight and Arnott.Methods: Powdered leaves were extracted with n-hexane (HE) and the defatted marc was extracted with 70% ethanol. The defatted ethanolic extract (DEE) was further partitioned with solvents of increasing polarities. The HE and polar fractions of DEE were purified using different chromatographic techniques and isolated compounds were identified through their melting points, 1D and 2D NMR, UV and MS spectral data.Results: A total of nine compounds were isolated and identified. Taraxerol (1), a pentacyclic triterpene, and β-sitosterol (2) were isolated from HE. Investigation of polar fractions of DEE yielded six flavonoids and a phenolic acid, namely luteolin (3), quercetin (4), gallic acid (5), avicularin (6), quercitrin (7), hyperoside (8) and quercetin-3-O-β-sophoroside (9).Conclusion: Flavonols of the quercetin nucleus were the major detected constituents in B. vahlii leaves. Taraxerol, avicularin and quercetin-3-O-β-sophoroside are isolated for the first time from the genus Bauhinia. Results of this study encourage future pharmacological investigation of B. vahlii due to the presence of biologically active flavonoids and phytosterols.Keywords: Bauhinia vahlii Wight, Arnott., Polar extractives, Flavonols, Quercetin, TaraxerolÂ

    Evaluation of the probiotic potential of lactic acid bacteria isolated from faeces of breast-fed infants in Egypt

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    The probiotic-related characteristics of 55 strains of lactic acid bacteria isolated from the faeces of 3 - 6 months old breast-fed infants were determined. The API 50 CH and SDS-PAGE techniques wereemployed to ascertain the identity of the isolated strains. The predominant species among the isolated strains were Lactobacillus (Lb.) acidophilus, Lb. plantarum, Enterococcus (E.) faecium, and E. faecalis. Probiotic properties such as bile resistance, acid tolerance, and adhesion to intestinal mucous were assessed. In vitro results obtained showed that five strains, Lb. plantarum (P1 and P164), Lb. pentosus (P191), and Lb. fermentum (P10, P193) were able to meet the basic requirements for probiotic functions as they demonstrated probiotic characteristics such as tolerance to pH 3, growth in 0.4% oxgall and adhesion to intestinal mucous. The results obtained in this investigation will be used to selectpotentially probiotic strains for in vivo study

    The effect of auditory stimulation on pain response of preterm infants

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    This study aimed to evaluate the effect of auditory stimulation on preterm infants' pain responses. A quasi-experimental design was utilized in this study. Thirty preterm infants were recruited for the study. They were one group used for three days as day one (routine care), day two (music intervention) and day three (recorded mother voice intervention) before, during and after blood sample procedure (heel prick) from Cairo University hospitals (El Monira and Kasar Aini). A tool containing two parts was used for data collection: 1) socio-demographic data for the preterm infants and the mothers, 2) Premature Infant Pain Profile (PIPP) tool for physiological responses (heart rate, oxygen saturation) behavioral state, brow bulge, eye squeeze, nasolabial furrow and respiratory rate was determined. Results of the study showed that during heel prick the majority of preterm infants (96.7%) who were exposed to recorded mother voice had highly statistical significant no or minimal pain followed by music groups (66.7%). On the other hand, nearly half of the cases (46.7%) had moderate pain and (30%) had severe pain among control group. There were significant differences between the three groups in the behavioral state, brow bulge, eye squeeze and nasolabial furrow (P≤0.001) and improved oxygen saturation (P≤0.05). After heel prick, the preterm infants (100%) who were exposed to recorded mother voice had highly statistically significant no or minimal pain in the items of behavioral state, eye squeeze and nasolabial furrow (P≤0.001), brow bulge was significantly lower (P≤0.05) when comparing by control or music group. In Conclusion, exposure to recorded mother voice during heel prick of preterm infants is better than exposure to music or no intervention and this was manifested by lower pain level, decrease heart rate, improved oxygen saturation and respiration. Key words: Auditory stimulation; recorded mother voice; music; pain response; physiological responses; behavioral stat

    Citric Acid Optimization by Candida tropicalis under Submerged Fermentation Conditions Using a Plackett-Burman Design

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    Citric acid production by fermentation is the most widely used way of obtaining it. The effects of some medium components were evaluated for Citric acid fermentation during the 1930s and 1940s.This work aimed to optimize citric acid by Candida tropicalis under submerged fermentation conditions using Plackett-Burman design. Some factors were tested as main variables affecting citric acid production using Plackett-Burman design. The results showed that incubation period of 7 days and pH 7; sodium acetate (10g/L), magnesium sulfate (1.5g/L), potassium phosphate (5g/L), ammonium chloride (3g/L), ferric sulfate(140mg/L), manganese sulfate (50 mg/L), zinc sulfate (80 mg/L), yeast extract (5.0g/L), glucose (150g/L), aeration ratio (75ml medium/ flask 250ml) were the most effective conditions for the highest yield of citric acid. The highest citric acid concentration was 30.0 g/L of the medium under the aforementioned conditions

    Solar Flares and Coronal Mass Ejections: A Statistically Determined Flare Flux-CME Mass Correlation

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    In an effort to examine the relationship between flare flux and corresponding CME mass, we temporally and spatially correlate all X-ray flares and CMEs in the LASCO and GOES archives from 1996 to 2006. We cross-reference 6,733 CMEs having well-measured masses against 12,050 X-ray flares having position information as determined from their optical counterparts. For a given flare, we search in time for CMEs which occur 10-80 minutes afterward, and we further require the flare and CME to occur within +/-45 degrees in position angle on the solar disk. There are 826 CME/flare pairs which fit these criteria. Comparing the flare fluxes with CME masses of these paired events, we find CME mass increases with flare flux, following an approximately log-linear, broken relationship: in the limit of lower flare fluxes, log(CME mass)~0.68*log(flare flux), and in the limit of higher flare fluxes, log(CME mass)~0.33*log(flare flux). We show that this broken power-law, and in particular the flatter slope at higher flare fluxes, may be due to an observational bias against CMEs associated with the most energetic flares: halo CMEs. Correcting for this bias yields a single power-law relationship of the form log(CME mass)~0.70*log(flare flux). This function describes the relationship between CME mass and flare flux over at least 3 dex in flare flux, from ~10^-7 to 10^-4 W m^-2.Comment: 28 pages, 16 figures, accepted to Solar Physic

    Prioritization of zoonoses for multisectoral, One Health collaboration in Somalia, 2023

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    Background: The human population of Somalia is vulnerable to zoonoses due to a high reliance on animal husbandry. This disease risk is exacerbated by relatively low income (poverty) and weak state capacity for health service delivery in the country as well as climate extremes and geopolitical instability in the region. To address this threat to public health efficiently and effectively, it is essential that all sectors have a common understanding of the priority zoonotic diseases of greatest concern to the country. Methods: Representatives from human, animal (domestic and wildlife), agriculture, and environmental health sectors undertook a multisectoral prioritization exercise using the One Health Zoonotic Disease Prioritization (OHZDP) tool developed by the United States CDC. The process involved: reviewing available literature and creating a longlist of zoonotic diseases for potential inclusion; developing and weighting criteria for establishing the importance of each zoonoses; formulating categorical questions (indicators) for each criteria; scoring each disease according to the criteria; and finally ranking the diseases based on the final score. Participants then brainstormed and suggested strategic action plans to prevent, and control prioritized zoonotic diseases. Results: Thirty-three zoonoses were initially considered for prioritization. Final criteria for ranking included: 1) socioeconomic impact (including sensitivity) in Somalia; 2) burden of disease in humans in Somalia); 3) availability of intervention in Somalia; 4) environmental factors/determinants; and 5) burden of disease in animals in Somalia. Following scoring of each zoonotic disease against these criteria, and further discussion of the OHZDP tool outputs, seven priority zoonoses were identified for Somalia: Rift Valley fever, Middle East respiratory syndrome, anthrax, trypanosomiasis, brucellosis, zoonotic enteric parasites (including Giardia and Cryptosporidium), and zoonotic influenza viruses. Conclusions: The final list of seven priority zoonotic diseases will serve as a foundation for strengthening One Health approaches for disease prevention and control in Somalia. It will be used to: shape improved multisectoral linkages for integrated surveillance systems and laboratory networks for improved human, animal, and environmental health; establish multisectoral public health emergency preparedness and response plans using One Health approaches; and enhance workforce capacity to prevent, control and respond to priority zoonotic diseases
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