Гальванохімічне формування багатокомпонентного сплаву на основі кобальта та тугоплавких металів

Effects of major parameters of electrolysis on the composition and morphology of the cobalt-molybdenum-tungsten alloy from citrate- pyrophosphate and citrate-ammonium electrolytes have been analysed. It has been shown that the content of component metals in the Co-W-Mo alloy depends on the nature and composition of the electrolyte solution. The influence of electrolysis conditions and regime on the structure and morphology of cobalt alloys with refractory metals has been established. The elemental composition and morphology of the triple cobalt - molybdenum - tungsten coatings have been determined with a scanning electron microscope.Проаналізовано вплив основних параметрів електролізу на склад та морфологію сплаву кобальт-молібден-вольфрам отриманого з цитратно-дифосфатного та цитратно-амоніачного електролітів. За допомогою сканівного електронного мікроскопу досліджено склад і морфологію потрійних покриттів. Було показано, що вміст компонентів в сплаві Со-W-Мо залежить від природи ліганда і співвідношення концентрацій сплавотвірних металів. Встановлено вплив густини струму, а також часу імпульсу та паузи на структуру і морфологію покриттів

Highly sensitive biofunctionalized nickel oxide nanowires for nanobiosensing applications

We report results of the studies relating to the fabrication of nickel oxide nanowires (NwNiOs) with an enhanced aspect ratio of similar to 100 for biosensing applications. Anti Vibrio cholerae monoclonal antibodies were used to functionalize the nickel oxide nanowire (20-80 nm) surfaces fabricated on indium tin oxide coated glass plate for Vibrio cholerae detection. The results of the impedance response studies conducted using this immunoelectrode as a function of the Vibrio cholerae concentration revealed a detection range of 37-350 ng ml(-1) and a low detection limit of 0.553 ng ml(-1) using the 3 sigma(b)/m criteria. The high sensitivity (11.12 Omega (ng ml(-1))(-1) cm(-2)) of this fabricated sensor is attributed to the excellent electronic properties of NiO nanowires which facilitate the efficient transfer of electrons between the electrode and the antibody molecules through electron channeling effects. Besides this, the nanostructured NiO nanowire based immunosensor exhibits interesting supercapacitive behaviour towards the detection of CT. This immunosensor showed values of association constant (K-a) of 4.5 x 10(7) ng ml(-1) and dissociation constant (K-d) of 2.22 x 10(-6) ng ml(-1)

Функциональные покрытия тройными сплавами кобальта с тугоплавкими металлами

Finely crystalline cobalt–molybdenum–tungsten coatings were deposited in the nonsteady-state mode from a polyligand citrate-pyrophosphate electrolyte at a concentration ratio of the alloy-forming components Со²⁺ / (WO₄²⁻ + MoO₄²⁻) = 1 : 1 and citrate/pyrophosphate ligands of 1 : 2. It was found that the quantitative composition and current efficiency by the ternary alloy depends on the current density. The effect of energy and time-related parameters of the pulsed electrolysis on the surface morphology and roughness was studied. It was shown that, as the total content of refractory metals in Co–Mo–W coatings increases, the corrosion rate decreases in the acid medium and increases in the alkaline medium because of the instability of molybdenum and tungsten oxides.Из полилигандного цитратно-пирофосфатного электролита при соотношении концентраций сплавообразующих компонентов Со²⁺ / (WO₄²⁻ + MoO₄²⁻) = 1:1, и лигандов цитрат / пирофосфат = 1 : 2 в нестационарном режиме получены мелкокристаллические покрытия кобальт–молибден–вольфрам. Установлена зависимость количественного состава и выхода по току тройного сплава от плотности тока. Исследовано влияние энергетических и временных параметров импульсного электролиза на морфологию и шероховатость поверхности. Показано, что при увеличении суммарного содержания тугоплавких металлов в покрытиях Co–Мо–W скорость коррозии в кислой среде снижается, а в щелочной увеличивается из-за неустойчивости оксидов молибдена и вольфрама

Синтез та фотокаталітична активність покривів Ti/TinOm ∙ ZrxOy для знешкодження азобарвників

Anodic oxidation of ВТ1-0 titanium and E-125 zirconium alloy in aqueous electrolyte solutions based on H2SO4 and K4P2O7 was used to obtain oxide coatings composed of Zr/ZrO2, Ti/TiO2, and mixed oxide systems Ti/TinOm· Zr xOy with synergetic effect. It was established mixed oxide materials contain from 0.17 up to 2.1 % wt. of zirconium. The catalytic activity of the synthesized coatings in the oxidation reaction of the methyl orange azo-dye under UV irradiation was shown. The process rate constants and synergy factors for the mixed systems were calculated.Анодним оксидуванням сплаву титану марки ВТ1-0 та цирконію марки Е-125 у водних розчинах електролітів H2SO4 й K4P2O7 одержано оксидні покриви складу Zr/ZrO2, Ti/TiO2, а також змішані оксидні системи Ti/TinOm ∙ ZrxOy з синергетичним ефектом. Встановлено, що змішані оксидні матеріали містять від 0,17 до 2,1% мас. цирконію. Визначено каталітичну активність синтезованих покривів у реакції окиснення азобарвника метилового жовтогарячого під дією УФ-випромінювання, визначені константи швидкості процесу та фактори синергізму для змішаних систем

Brain Region–Specific Decrease in the Activity and Expression of Protein Kinase A in the Frontal Cortex of Regressive Autism

Autism is a severe neurodevelopmental disorder that is characterized by impaired language, communication, and social skills. In regressive autism, affected children first show signs of normal social and language development but eventually lose these skills and develop autistic behavior. Protein kinases are essential in G-protein-coupled, receptor-mediated signal transduction and are involved in neuronal functions, gene expression, memory, and cell differentiation. We studied the activity and expression of protein kinase A (PKA), a cyclic AMP–dependent protein kinase, in postmortem brain tissue samples from the frontal, temporal, parietal, and occipital cortices, and the cerebellum of individuals with regressive autism; autistic subjects without a clinical history of regression; and age-matched developmentally normal control subjects. The activity of PKA and the expression of PKA (C-α), a catalytic subunit of PKA, were significantly decreased in the frontal cortex of individuals with regressive autism compared to control subjects and individuals with non-regressive autism. Such changes were not observed in the cerebellum, or the cortices from the temporal, parietal, and occipital regions of the brain in subjects with regressive autism. In addition, there was no significant difference in PKA activity or expression of PKA (C-α) between non-regressive autism and control groups. These results suggest that regression in autism may be associated, in part, with decreased PKA-mediated phosphorylation of proteins and abnormalities in cellular signaling

Protective Effects of Walnut Extract Against Amyloid Beta Peptide-Induced Cell Death and Oxidative Stress in PC12 Cells

Amyloid beta-protein (Aβ) is the major component of senile plaques and cerebrovascular amyloid deposits in individuals with Alzheimer’s disease. Aβ is known to increase free radical production in neuronal cells, leading to oxidative stress and cell death. Recently, considerable attention has been focused on dietary antioxidants that are able to scavenge reactive oxygen species (ROS), thereby offering protection against oxidative stress. Walnuts are rich in components that have anti-oxidant and anti-inflammatory properties. The inhibition of in vitro fibrillization of synthetic Aβ, and solubilization of preformed fibrillar Aβ by walnut extract was previously reported. The present study was designed to investigate whether walnut extract can protect against Aβ-induced oxidative damage and cytotoxicity. The effect of walnut extract on Aβ-induced cellular damage, ROS generation and apoptosis in PC12 pheochromocytoma cells was studied. Walnut extract reduced Aβ-mediated cell death assessed by MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) reduction, and release of lactate dehydrogenase (membrane damage), DNA damage (apoptosis) and generation of ROS in a concentration-dependent manner. These results suggest that walnut extract can counteract Aβ-induced oxidative stress and associated cell death

A Plant DJ-1 Homolog Is Essential for Arabidopsis thaliana Chloroplast Development

Protein superfamilies can exhibit considerable diversification of function among their members in various organisms. The DJ-1 superfamily is composed of proteins that are principally involved in stress response and are widely distributed in all kingdoms of life. The model flowering plant Arabidopsis thaliana contains three close homologs of animal DJ-1, all of which are tandem duplications of the DJ-1 domain. Consequently, the plant DJ-1 homologs are likely pseudo-dimeric proteins composed of a single polypeptide chain. We report that one A. thaliana DJ-1 homolog (AtDJ1C) is the first DJ-1 homolog in any organism that is required for viability. Homozygous disruption of the AtDJ1C gene results in non-viable, albino seedlings that can be complemented by expression of wild-type or epitope-tagged AtDJ1C. The plastids from these dj1c plants lack thylakoid membranes and granal stacks, indicating that AtDJ1C is required for proper chloroplast development. AtDJ1C is expressed early in leaf development when chloroplasts mature, but is downregulated in older tissue, consistent with a proposed role in plastid development. In addition to its plant-specific function, AtDJ1C is an atypical member of the DJ-1 superfamily that lacks a conserved cysteine residue that is required for the functions of most other superfamily members. The essential role for AtDJ1C in chloroplast maturation expands the known functional diversity of the DJ-1 superfamily and provides the first evidence of a role for specialized DJ-1-like proteins in eukaryotic development

How are gender inequalities facing India’s one million ASHAs being addressed? Policy origins and adaptations for the world’s largest all-female community health worker programme

Background: India’s accredited social health activist (ASHA) programme consists of almost one million female community health workers (CHWs). Launched in 2005, there is now an ASHA in almost every village and across many urban centres who support health system linkages and provide basic health education and care. This paper examines how the programme is seeking to address gender inequalities facing ASHAs, from the programme's policy origins to recent adaptations. Methods: We reviewed all publically available government documents (n = 96) as well as published academic literature (n = 122) on the ASHA programme. We also drew from the embedded knowledge of this paper’s government-affiliated co-authors, triangulated with key informant interviews (n = 12). Data were analysed thematically through a gender lens. Results: Given that the initial impetus for the ASHA programme was to address reproductive and child health issues, policymakers viewed volunteer female health workers embedded in communities as best positioned to engage with beneficiaries. From these instrumentalist origins, where the programme was designed to meet health system demands, policy evolved to consider how the health system could better support ASHAs. Policy reforms included an increase in the number and regularity of incentivized tasks, social security measures, and government scholarships for higher education. Residential trainings were initiated to build empowering knowledge and facilitate ASHA solidarity. ASHAs were designated as secretaries of their village health committees, encouraging them to move beyond an all-female sphere and increasing their role in accountability initiatives. Measures to address gender based violence were also recently recommended. Despite these well-intended reforms and the positive gains realized, ongoing tensions and challenges related to their gendered social and employment status remain, requiring continued policy attention and adaptation

In Vitro Surfactant Structure-Toxicity Relationships: Implications for Surfactant Use in Sexually Transmitted Infection Prophylaxis and Contraception

Background The need for woman-controlled, cheap, safe, effective, easy-to-use and easy-to-store topical applications for prophylaxis against sexually transmitted infections (STIs) makes surfactant-containing formulations an interesting option that requires a more fundamental knowledge concerning surfactant toxicology and structure-activity relationships. Methodology/Principal Findings We report in vitro effects of surfactant concentration, exposure time and structure on the viability of mammalian cell types typically encountered in the vagina, namely, fully polarized and confluent epithelial cells, confluent but non-polarized epithelial-like cells, dendritic cells, and human sperm. Representatives of the different families of commercially available surfactants – nonionic (Triton X-100 and monolaurin), zwitterionic (DDPS), anionic (SDS), and cationic (CnTAB (n = 10 to 16), C12PB, and C12BZK) – were examined. Triton X-100, monolaurin, DDPS and SDS were toxic to all cell types at concentrations around their critical micelle concentration (CMC) suggesting a non-selective mode of action involving cell membrane destabilization and/or destruction. All cationic surfactants were toxic at concentrations far below their CMC and showed significant differences in their toxicity toward polarized as compared with non-polarized cells. Their toxicity was also dependent on the chemical nature of the polar head group. Our results suggest an intracellular locus of action for cationic surfactants and show that their structure-activity relationships could be profitably exploited for STI prophylaxis in vaginal gel formulations. The therapeutic indices comparing polarized epithelial cell toxicity to sperm toxicity for all surfactants examined, except C12PB and C12BZK, does not justify their use as contraceptive agents. C12PB and C12BZK are shown to have a narrow therapeutic index recommending caution in their use in contraceptive formulations. Conclusions/Significance Our results contribute to understanding the mechanisms involved in surfactant toxicity, have a predictive value with regard to their safety, and may be used to design more effective and less harmful surfactants for use in topical applications for STI prophylaxis.Foundation for Science and Technology of the Portuguese Ministry of Science and Higher Educatio

Using C. elegans to discover therapeutic compounds for ageing-associated neurodegenerative diseases

Age-associated neurodegenerative disorders such as Alzheimer’s disease are a major public health challenge, due to the demographic increase in the proportion of older individuals in society. However, the relatively few currently approved drugs for these conditions provide only symptomatic relief. A major goal of neurodegeneration research is therefore to identify potential new therapeutic compounds that can slow or even reverse disease progression, either by impacting directly on the neurodegenerative process or by activating endogenous physiological neuroprotective mechanisms that decline with ageing. This requires model systems that can recapitulate key features of human neurodegenerative diseases that are also amenable to compound screening approaches. Mammalian models are very powerful, but are prohibitively expensive for high-throughput drug screens. Given the highly conserved neurological pathways between mammals and invertebrates, Caenorhabditis elegans has emerged as a powerful tool for neuroprotective compound screening. Here we describe how C. elegans has been used to model various human ageing-associated neurodegenerative diseases and provide an extensive list of compounds that have therapeutic activity in these worm models and so may have translational potential