120 research outputs found

    Impedance Characterization of DNA-functionalization Layers on AlGaN/GaN High Electron Mobility Transistors

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    AbstractCharacterization and optimization for biosensor implementation with open gate AlGaN/GaN transistors is described. Probe-DNA was immobilized on the gate. As target, complementary DNA at 10-12 - 10-7mol/L was added. To investigate the impedimetric properties of the sensing area, electrochemical impedance spectroscopy was used. For very low frequencies, the bio-functionalization layer was modeled as a membrane with a charge transfer resistor in series with a Warburg element. This component presents impedance to diffusion of electrolyte ions. Its behavior is intermediate between a capacitor and a resistor (membrane impedance). After probe-target matching, the charge transfer resistance and Warburg impedance were increased (lower flow of electrolyte ions through the membrane). Using this working principle, a dynamic detection of targets is proposed

    Prevalence and Correlates of Common Mental Disorders among Mothers of Young Children in Kilimanjaro Region of Tanzania.

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    Although poor maternal mental health is a major public health problem, with detrimental effects on the individual, her children and society, information on its correlates in low-income countries is sparse. This study investigates the prevalence of common mental disorders (CMD) among at-risk mothers, and explores its associations with sociodemographic factors. This population-based survey of mothers of children aged 0-36 months used the 14-item Shona Symptom Questionnaire (SSQ). Mothers whose response was "yes" to 8 or more items on the scale were defined as "at risk of CMD." Of the 1,922 mothers (15-48 years), 28.8% were at risk of CMD. Risk of CMD was associated with verbal abuse, physical abuse, a partner who did not help with the care of the child, being in a polygamous relationship, a partner with low levels of education, and a partner who smoked cigarettes. Cohabiting appeared to be protective. Taken together, our results indicate the significance of the quality of relations with one's partner in shaping maternal mental health. The high proportion of mothers who are at risk of CMD emphasizes the importance of developing evidence-based mental health programmes as part of the care package aimed at improving maternal well-being in Tanzania and other similar settings

    Environmental and cultivar variability in composition, content and biological activity of phenolic acids and alkylresorcinols of winter wheat grains from a multi-site field trial across Europe

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    Different factors such as the genotype, environmental conditions, temperature stress, solar radiation and others can influence the phytochemical status of plants. The concentration of phenolic acids and alkylresorciols (ARs) as well as their chemical composition and biological activity have been determined in twelve winter wheat cultivars grown at eight European locations. This was the first winter wheat multi-location field trial of the European Consortium for Open Field Experimentation (ECOFE). Extracts from grain were analyzed using a UPLC-PDA-ESI MS system (phenolic acids), UPLC-PDA-MS/MS (alkylresorcinols) and TLC-DPPH• test with ImageJ program (antiradical activity). The phenolic acid profile consisted of five hydroxybenzoic acid and four hydroxycinnamic acid derivatives, among which ferulic and sinapic acids were predominated. The ARs profile consisted of nine AR derivatives, among which 5-n-heneicosylresorcinol (C21:0) and 5-n-nonadecanylresorcinol (C19:0) were pre dominated. Our study showed significant differences in phenolic acids and AR content between wheat cultivars, as well as between locations. We observed a positive correlation between the biological activity of extracts and the total amount of phenolic acids and ARs. Two cultivars, Chambo and Julius (average of all sites) and samples from the Spanish site (average of all cultivars) showed the highest content and composition of nutritional substances

    Environmental and cultivar variability in composition, content and biological activity of phenolic acids and alkylresorcinols of winter wheat grains from a multi-site field trial across Europe

    Get PDF
    Different factors such as the genotype, environmental conditions, temperature stress, solar radiation and others can influence the phytochemical status of plants. The concentration of phenolic acids and alkylresorciols (ARs) as well as their chemical composition and biological activity have been determined in twelve winter wheat cultivars grown at eight European locations. This was the first winter wheat multi-location field trial of the European Consortium for Open Field Experimentation (ECOFE). Extracts from grain were analyzed using a UPLC-PDA-ESI-MS system (phenolic acids), UPLC-PDA-MS/MS (alkylresorcinols) and TLC-DPPH• test with ImageJ program (antiradical activity). The phenolic acid profile consisted of five hydroxybenzoic acid and four hydroxycinnamic acid derivatives, among which ferulic and sinapic acids were predominated. The ARs profile consisted of nine AR derivatives, among which 5-n-heneicosylresorcinol (C21:0) and 5-n-nonadecanylresorcinol (C19:0) were predominated. Our study showed significant differences in phenolic acids and AR content between wheat cultivars, as well as between locations. We observed a positive correlation between the biological activity of extracts and the total amount of phenolic acids and ARs. Two cultivars, Chambo and Julius (average of all sites) and samples from the Spanish site (average of all cultivars) showed the highest content and composition of nutritional substances.info:eu-repo/semantics/publishedVersio

    Population structure of anisakis simplex (nematoda) in harbor porpoises phocoena phocoena off Denmark

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    The population structure and habitat selection of Anisakis simplex in 35 harbor porpoises off Denmark are described. The nematodes were collected from the stomach and duodenal ampulla and were categorized as third-stage larvae, fourth-stage larvae, subadults, and adults. The porpoises harbored 8,043 specimens of A. simplex. The proportion of adults and subadults increased with infrapopulation size. The number of development stages across infrapopulations covaried significantly (Kendall's test of concordance). Concordance was higher in hosts with the highest intensities than in those with low and medium intensities. All stages occurred mainly in the forestomach, but this trend was stronger for the adults. Adult and subadult sex ratios did not depart significantly from 1:1. Our data suggested that recruitment and duration of each stage were the main factors accounting for infrapopulation structure. The preference of A. simplex for the forestomach conformed with previous studies, but the narrower distribution of adults relative to other stages might indicate a strategy to enhance mating opportunities. Information on sex ratios of A. simplex is scarce and contradictory. We suggest that the discrepancies might partly reflect differences in categorization criteria and statistical methods.Herreras Belled, Maria Victoria, [email protected] ; Balbuena Diaz-Pines, Juan Antonio, [email protected] ; Aznar Avendaño, Francisco Javier, [email protected] ; Raga Esteve, Juan Antonio, [email protected]

    Validated spectrophotometric methods for determination of Alendronate sodium in tablets through nucleophilic aromatic substitution reactions

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    <p>Abstract</p> <p>Background</p> <p>Alendronate (ALD) is a member of the bisphosphonate family which is used for the treatment of osteoporosis, bone metastasis, Paget's disease, hypocalcaemia associated with malignancy and other conditions that feature bone fragility. ALD is a non-chromophoric compound so its determination by conventional spectrophotometric methods is not possible. So two derivatization reactions were proposed for determination of ALD through the reaction with 4-chloro-7-nitrobenzo-2-oxa-1,3-diazole (NBD-Cl) and 2,4-dinitrofluorobenzene (DNFB) as chromogenic derivatizing reagents.</p> <p>Results</p> <p>Three simple and sensitive spectrophotometric methods are described for the determination of ALD. Method I is based on the reaction of ALD with NBD-Cl. Method II involved heat-catalyzed derivatization of ALD with DNFB, while, Method III is based on micellar-catalyzed reaction of the studied drug with DNFB at room temperature. The reactions products were measured at 472, 378 and 374 nm, for methods I, II and III, respectively. Beer's law was obeyed over the concentration ranges of 1.0-20.0, 4.0-40.0 and 1.5-30.0 μg/mL with lower limits of detection of 0.09, 1.06 and 0.06 μg/mL for Methods I, II and III, respectively. The proposed methods were applied for quantitation of the studied drug in its pure form with mean percentage recoveries of 100.47 ± 1.12, 100.17 ± 1.21 and 99.23 ± 1.26 for Methods I, II and III, respectively. Moreover the proposed methods were successfully applied for determination of ALD in different tablets. Proposals of the reactions pathways have been postulated.</p> <p>Conclusion</p> <p>The proposed spectrophotometric methods provided sensitive, specific and inexpensive analytical procedures for determination of the non-chromophoric drug alendronate either per se or in its tablet dosage forms without interference from common excipients.</p> <p>Graphical abstract</p> <p><display-formula><graphic file="1752-153X-6-25-i3.gif"/></display-formula></p

    A Comprehensive Expression Profile of MicroRNAs in Porcine Pituitary

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    MicroRNAs (miRNAs) are an abundant class of small RNAs that regulate expressions of most genes. miRNAs play important roles in the pituitary, the “master” endocrine organ.However, we still don't know which role miRNAs play in the development of pituitary tissue or how much they contribute to the pituitary function. By applying a combination of microarray analysis and Solexa sequencing, we detected a total of 450 miRNAs in the porcine pituitary. Verification with RT-PCR showed a high degree of confidence for the obtained data. According to the current miRBase release17.0, the detected miRNAs included 169 known porcine miRNAs, 163 conserved miRNAs not yet identified in the pig, and 12 potentially new miRNAs not yet identified in any species, three of which were revealed using Northern blot. The pituitary might contain about 80.17% miRNA types belonging to the animal. Analysis of 10 highly expressed miRNAs with the Kyoto Encyclopedia of Genes and Genomes (KEGG) indicated that the enriched miRNAs were involved not only in the development of the organ but also in a variety of inter-cell and inner cell processes or pathways that are involved in the function of the organ
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