838 research outputs found

    Tunable morphological properties of silver enriched platinum allied nanoparticles and their catalysed reduction of p-nitrophenol

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    A robust polymer based and polyol mediated procedure to synthesize nanobimetallic particles has been modified to produce core–shell and alloy Ag/Pt nanoparticles with tunable properties. Novel three-dimensional (3D) quasi nanocubes entangled in nanowebs were produced by rapid solution phase transformation with hot addition of absolute ethanol. The optical characterization showed extinction of plasmon resonance band occurring with incremental feeding ratio of Pt source in all cases. Transmission electron microscope (TEM) and high resolution transmission electron microscope (HRTEM) images revealed that the shape, size and size distribution of asprepared silver platinum nanoparticles depended on the stabilizer or capping agent, mole ratio of metal ion sources, temperature and time of reaction. Meanwhile, catalytic activity was highest in the reduction of p-nitrophenol in the presence of polyvinylpyrrolidone/diethylene glycol stabilized Ag/Pt nanoparticles

    Interactions of cross-linked and uncross-linked chitosan hydrogels with surfactants for biomedical applications

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    The swelling equilibrium of Chitosan and sodium tripolyphosphate (NaTPP) cross-linked chitosan hydrogels in aqueous solutions of surfactants differing in structure and hydrophobicity at 250C is reported. Anionic surfactant sodium dodecylsulfate (SDS), the cationic surfactant hexadecyltrimethylammonium bromide (HTAB) and neutral surfactants Triton X-100 were employed. The surfactants induced abrupt change in the gel volume. The equilibrium swelling ratio first decreased sharply as the concentration of the surfactant increased and remained almost constant up to the critical micelles concentration (CMC) of the surfactants and then increased again as the concentration increased above the CMC of the surfactants used. The equilibrium volume change of hydrogel was significantly increased from HTAB > Triton X-100 > SDS> the mixed SDS/Triton X- 100 system. A decrease in equilibrium swelling ratio of the gel in SDS/TX-100 mixtures was observed with an increase in the mole ratio of SDS. The results also revealed that cross-linking with 3% or 5% w/v NaTPP exhibited lower equilibrium swelling values. This swelling study showed that cross-linking density, surfactant type, and their respective concentrations were important parameters that could affect equilibrium swelling of chitosan gel. Structural elucidation of the nanocomposites was monitored using Infra-red Spectroscopy (IR), and X-Ray Diffractography (XRD)

    Green Synthesized Optically Active Organically Capped Silver Nanoparticles using Stem Extract of African Cucumber(Momordica charantia)

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    Silver nanoparticles (Ag NPs) were synthesized by a rapid facile plant-mediated green route. Sustainable and renewable stem extract of locally sourced African cucumber acted as reducing/capping agent, an alternative to toxic chemicals. The phytochemical screening indicated the existence of saponins and alkaloids in the stem extract of M. charantia. Unprecedented nucleation and growth of Ag NPs commenced within 5 minutes of the reaction. The mechanism of reaction was considered to be diffusion controlled Ostwald ripening process. Optical property of the as prepared Ag NPs was characterized by high intensity of absorption, revealed by narrow intense peaks, stipulating confinement of excitons.Surface Plasmon Band (SPB) of Ag NPs appeared at 400 - 460 nm. Photoluminescence (PL)excitation of the Ag NPs at 329 nm exhibited excitonic emission at 440 nm. The Ag NPs portrayed quasi-spherical shapes, with a mean size of 27.81 ± 1.64 nm from Transmission Electron Micrograph (TEM) measurement. XRD measurement showed peaks indexed to fcc Ag with a particle diameter of 25 nm, which corroborated TEM measurement. Elemental mapping of the nanoparticles showed an orientation of the Ag NPs, an evidence of capping by the biomolecules which stabilized the newly formed Ag NPs. Fourier Transformed Infra-red (FTIR) analysis showed the presence of hydroxyl groups (−OH) stretching, (−CH) stretching,C=C stretching and C−N group (in the phytochemicals) at 3237, 2913, 1620 and 1021 cm-1 respectively. It can be inferred that the as prepared Ag NPs is an optically active material

    Differentiating Plasmodium falciparum alleles by transforming Cartesian X,Y data to polar coordinates

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    <p>Abstract</p> <p>Background</p> <p>Diagnosis of infectious diseases now benefits from advancing technology to perform multiplex analysis of a growing number of variables. These advances enable simultaneous surveillance of markers characterizing species and strain complexity, mutations associated with drug susceptibility, and antigen-based polymorphisms in relation to evaluation of vaccine effectiveness. We have recently developed assays detecting single nucleotide polymorphisms (SNPs) in the <it>P. falciparum </it>genome that take advantage of post-PCR ligation detection reaction and fluorescent microsphere labeling strategies. Data from these assays produce a spectrum of outcomes showing that infections result from single to multiple strains. Traditional methods for distinguishing true positive signal from background can cause false positive diagnoses leading to incorrect interpretation of outcomes associated with disease treatment.</p> <p>Results</p> <p>Following analysis of <it>Plasmodium falciparum </it>dihydrofolate reductase SNPs associated with resistance to a commonly used antimalarial drug, Fansidar (Sulfadoxine/pyrimethamine), and presumably neutral SNPs for parasite strain differentiation, we first evaluated our data after setting a background signal based on the mean plus three standard deviations for known negative control samples. Our analysis of single allelic controls suggested that background for the absent allele increased as the concentration of the target allele increased. To address this problem, we introduced a simple change of variables from customary (<it>X,Y</it>) (Cartesian) coordinates to planar polar coordinates (<it>X </it>= <it>r</it>cos(<it>Ξ</it>), <it>Y </it>= <it>r</it>sin(<it>Ξ</it>)). Classification of multidimensional fluorescence signals based on histograms of angular and radial data distributions proved more effective than classification based on Cartesian thresholds. Comparison with known diallelic dilution controls suggests that histogram-based classification is effective for major:minor allele concentration ratios as high as 10:1.</p> <p>Conclusion</p> <p>We have observed that the diallelic SNP data resulting from analysis of <it>P. falciparum </it>mutations is more accurately diagnosed when a simple polar transform of the (<it>X,Y</it>) data into (<it>r,Ξ</it>) is used. The development of high through-put methods for genotyping <it>P. falciparum </it>SNPs and the refinement of analytical approaches for evaluating these molecular diagnostic results significantly advance the evaluation of parasite population diversity and antimalarial drug resistance.</p

    Synthesis of polyol based Ag/Pd nanocomposites for applications in catalysis

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    The synthesis of polyvinylpyrrolidone seed mediated Ag/Pd allied nanobimetallic particles was successfully carried out by the simultaneous reduction of the metal ions in ethylene glycol, diethylene glycol, glycerol, pentaerythritol and sodium borohydride solution. The optical measurement revealed the existence of peak broadening that causes diffusion processes of the metal sols to decrease making it possible to monitor the changes spectrophotometrically. This, together with X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM) and high resolution TEM measurements strongly support the conclusion that intimately alloyed clusters were formed and the particle growth anisotropy is diffusion limited. Finally, the catalytic potential of the nanocomposites was investigated using 4-nitrophenol in the presence of sodium borohydride at 299 K; a good linear fitting of ln (A/A0) versus the reaction time was obtained, indicating pseudo-first-order kinetic

    Ocimum gratissimum Ameliorates Gentamicin-Induced Kidney Injury but Decreases Creatinine Clearance Following Sub-Chronic Administration in Rats

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    The effects of aqueous extract of Ocimum gratissimum leaf (AOGL) on the renal function of rats with gentamicin-induced nephrotoxicity were investigated. This study involved the use of forty five (45) adult male Wistar rats (housed in separate metabolic cages) such that graded doses of OAGL were administered to the experimental groups (p.o.) for 28 days after exposure to gentamicin toxicity (100 mg/kg i.p.) for 1 week. At the end of the study, comparisons of some indices of renal function as well as antioxidant status (GSH and TBARS) were made between the control, toxic and AOGL-treated groups at P < 0.05. The result showed that gentamicin treatment caused significant increase (P < .05) in urine output, urea, creatinine, total protein, relative kidney weight, and TBARS, as well as significant decrease (P < .05) in urine creatinine and GSH levels. Post-treatment with graded doses of AOGL caused significant increase in food consumption, GSH, urine, and plasma creatinine, as well as significant decrease (P < .05) in relative kidney weight, TBARS, and urine total protein. There was an appreciable difference in the kidney histology of the AOGL-treated groups when compared with the toxic control. Hence, the extract has therapeutic potential in the management of gentamicin-induced kidney injury, although a risk profile of renal dysfunction is not unlikely from 28 days of administration as evident by the decrease in creatinine clearance

    Review of studies on the psychometric properties of mayer–salovey–caruso emotional intelligence test

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    The study reviewed notable reports on the psychometric properties of the Mayer- Salover-Caruso Emotional Intelligence Test [MSCEIT], with a focus on articles published in open-access SCOPUS indexed journals. Out of the initial 43 promising articles the search engine listed, only 8 met the inclusion criteria of offering useful information on reliability and validity of the ability-prone emotional intelligence test. The documentary research design was adopted. Qualitative analyses of the selected reports revealed that though the MSCEIT tend to furnish some evidence of internal consistency reliability cum construct and criterion validity over the years, it was still deficient in content validity, based on some missing indispensable dimensions of emotional intelligence. The content validity gap tends to put to question the authenticity of all the reported indices of validity of the MSCEIT, especially if we follow the psychometric principle that no psychological instrument can have acceptable construct and criterion validities without a robust content validity, irrespective of the robustness of the statistical treatment applied on the data thereof

    Biodiesel Fuel from Differently Sourced Local Seed Oils: Characterization, Effects of Catalysts, Total Glycerol Content and Flow Rates

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    The recently observed depletion in the petroleum resources, which also mainly constituted carbon dioxide emission and global warming problems call for renewable and sustainable alternative fuels. Oils were extracted from various seeds: Jatropha curcas (Botuje), Pentaclethra macrophylla (Apara) and soybean, using petroleum ether (40-60℃). Alkali catalyzed transesterification of the oils (biodiesel pro-duction) in the presence of different kinds of alcohol (methanol, ethanol and propanol) were carried out using sodium hydroxide as catalyst. In the case of Jatropha oil, potassium hydroxide served as catalyst. Effect of catalysts to obtain optimum biofuel was established. In the case of soybean oil, fatty acid methyl ester, FAME, (96%), fatty acid ethyl ester, FAEE, (84%) and fatty acid propyl ester, FAPE, (37.50%) were pro-duced. In waste palm kernel oil, methyl ester (72.92%) and ethyl ester (46.25%) were obtained. In refined palm kernel oil, methyl ester (70.83%), ethyl ester (66.67%) and (14.17%) propyl ester were produced. However, only methyl ester conversion (20.83%) was possible in Pen-taclethra macrophylla oil. In Jatropha curcas using KOH catalyst, only methyl ester (80%) formation was possible. Moreover, yields were af-fected as the alcohol alkyl became bulkier giving relatively lower value of biodiesel. Sulphur content (0.01) obtained for each of the biofuel was satisfactory when compared with ASTM standard (0.05 maximum). The cetane value of soybean oil (45.5), refined palm kernel oil (46) and used oil (44.6) were quite reasonable compared with the special standard (47). The combustion energy of the fuels from refined palm kernel oil, waste palm kernel oil and soybean are 39, 36 and 45.5 respectively. The total glycerol content (Gc) of the methyl and ethyl esters emanat-ed from soybean are quite reasonable and fell within standard

    Diversity of indigenous arbuscular mycorrhizal fungi in rhizosphere of upland rice (Oryza sativa L.) varieties in Southwest Nigeria

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    Article Details: Received: 2020-02-05      |      Accepted: 2020-05-07      |      Available online: 2020-06-30https://doi.org/10.15414/afz.2020.23.02.42-48 Arbuscular mycorrhizal fungi (AMF) have the potential to increase crop productivity and play a key role in the functioning and sustainability of most agroecosystems. However, limited information is available on the divervisity of AMF associated with upland rice varieties in Southwest Nigeria. Field survey was conducted to investigate colonization and diversity of AMF in 13 upland rice varieties commonly grown in Southwest Nigeria. Root and soil samples were collected from rice fields in 2012. The results showed natural root colonization of all the rice varieties by AMF with highest root colonization in ITA 157and Ofada. The spore densities retrieved from the different rhizospheres were relatively high, varying from 13 spores in UORW 111 to 174 spores in Ofada with a mean of 67.6 spores per 20 g dry soil. Glomus was observed to be the most abundant AMF genus. Funneliformis mosseae was the most frequently occurring AMF species (96.2%) with relative density (RD) of 32.2%, followed by Glomus intraradices, Claroideoglomus etunicatum, and Glomus clareium. This study showed that AMF naturally colonized the roots of these rice varieties and diversity of different AMF genera in rice rhizosphere. This study will help draw attention to natural colonization of AMF in rice producing areas of Nigeria that can influence future possibility of using inocula of the dominant AMF species in upland rice cultivation.Keywords: Arbuscular mycorrhizal fungi, community structure, diversity, upland rice, spore densityReferences ADEYEMI, N.O. et al. (2020). Effect of commercial arbuscular mycorrhizal fungi inoculant on growth and yield of soybean under controlled and natural field conditions. Journal of Plant Nutrition, 43(4), 487–499, DOI: https://doi.org/10.1080/019041 67.2019.1685101 ADEYEMI, N.O. et al. 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    A 6-month, multicenter, open-label study of fixed dose naproxen/esomeprazole in adolescent patients with juvenile idiopathic arthritis

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    © 2018 The Author(s). Background: Juvenile idiopathic arthritis (JIA) is an inflammatory arthritis of unknown etiology, which lasts for greater than 6 weeks with onset before 16 years of age. JIA is the most common chronic rheumatic disease in children. NSAIDs have been the mainstay of initial management with naproxen (NAP) being commonly used, but they may cause serious side effects such as gastric ulcers which can be reduced by concomitant administration of proton pump inhibitors, such as esomeprazole (ESO). Methods: Primary objective was to evaluate the safety and tolerability of 3 fixed doses of NAP/ESO in JIA patients aged 12 to 16 years. Forty-six children and adolescents with JIA by International League of Associations for Rheumatology criteria, mean age of 13.6 years, from 18 US sites were prospectively enrolled over 2 years and followed for up to 6 months. Doses of the NAP/ESO fixed combination were based on baseline weight. The exploratory efficacy outcome was assessed with the ACR Pediatric-30, - 50, - 70, - 90 Response and the Childhood Health Assessment Questionnaire (CHAQ) discomfort and functional scores at months 1, 3, and 6 as change from baseline. Occurrence and causality were assessed for treatment emergent AEs (TEAEs) and discontinuations were monitored monthly. Results: Forty-six patients received at least 1 dose of naproxen/esomeprazole and 36 completed the trial. Thirty-seven (80.4%) had at least 1 treatment emergent adverse event (TEAE) and, with the exception of 2 events in one patient, all of the TEAEs were mild or moderate. Frequent TEAEs (≄5% of patients) were upper respiratory tract and gastrointestinal related. Eleven (23.9%) had at least 1 TEAE considered to be related to study drug. Four patients (8.7%) discontinued due to a TEAE with one of these being the only serious AE reported, acute hepatitis. Mean number of active joints at baseline was 3.1. Improvement in JIA signs and symptoms occurred at most assessments and by month 6, the percentage of patients with an ACR Pediatric-30, - 50, - 70, and - 90 Response was 47.1, 38.2, 32.4, and 17.6%, respectively. The percent of patients achieving ACR Pediatric response increased over time. CHAQ discomfort improved at each assessment and functional scores improved at all assessments for \u27Arising, Walking, and Activities\u27 with several improved for \u27Dressing and Grooming, Eating, Hygiene, and Grip\u27. There was no indication of a dose-related efficacy effect. Conclusion: NAP/ESO was well tolerated in JIA patients aged 12 to 16 years with high levels of response to ACR criteria. No new safety signals were identified for the well-characterized components of this fixed dosed JIA treatment, which was developed to reduce the risk of gastric ulcers
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