16 research outputs found

    A fifteen atom silver cluster confined in bovine serum albumin

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    Luminescent Ag15 clusters confined in bovine serum albumin (BSA) have been prepared by a simple wet chemical route. The luminescence, exhibiting a maximum at 685 nm, is observable to the naked eye. The chemical composition of these clusters was analyzed using matrix assisted laser desorption ionization mass spectrometry (MALDI MS), X-ray photoelectron spectroscopy (XPS), and energy dispersive analysis of X-rays (EDAX). Intact Ag15@BSA is observed by MALDI MS. Multiple charge states of the cluster are observed confirming the mass assignment. The clusters showed a quantum yield of 10.71% in water and the luminescence was stable in a pH range of 1-12. Stability of the clusters was enhanced by the addition of polyvinylpyrrolidone (PVP). The clusters showed luminescence in the solid state as well. Evolution of clusters with variation in the amount of reducing agent added shows that the cluster formation goes through an intermediate state of bound silver, formed instantaneously after the addition of Ag+, which transforms to the cluster. High yield synthesis and exciting photophysical properties make our new material interesting for various applications such as biolabeling and imaging

    Molecular precursor-mediated tuning of gold mesostructures: synthesis and SERRS studies

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    This article describes the high yield synthesis of a range of anisotropic gold mesostructures such as flowers, cubes, plates, and quasispherical mesostructures using a seed-mediated approach. These structures were formed from precursor seed nanoparticles of gold stabilized by the template, 1,2-phenylenediamine (1,2-PDA). We demonstrated that control of the morphologies from mesoflowers to quasispherical structures is possible with the molecular precursors used in the synthesis of seeds. It was found that concentration of the template, 1,2-PDA added during seed preparation played an important role in the conversion of mesoflowers to quasispherical and cube-like structures. Scanning electron microscopy (SEM), transmission electron microscopy (TEM), UV-vis spectroscopy and energy dispersive analysis of X-rays (EDAX) were used for the determination of physical and chemical composition of the nano/mesostructures formed. The seed nanoparticles responsible for the formation of these various anisotropic structures were further characterized and analyzed using laser desorption ionization mass spectrometry (LDI MS) and TEM. We demonstrated high surface-enhanced resonance Raman scattering (SERRS) activity of the mesoflowers using crystal violet (CV) as the analyte molecule. The shape-dependent SERRS activity of various meso/nanostructures was also studied. A ~0.8×102 decrease in the SERRS intensity was observed in quasispherical structures compared to mesoflowers. The increased SERRS activity is attributed to the unique shape and nanofeatures present on the mesoflowers, which were absent in the quasispherical mesostructures. We believe that the high SERRS activity exhibited by the mesoflowers may be utilized for developing novel sensors

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    Not AvailableSeven species of prawns of different size caught during different seasons were analysed for fat, nonsaponifiable matter (NSM) and cholesterol for a period of 1 year. The cholesterol content was found to be not steady throughout the seasons with alternate ups and downs, the maximum being in August and November. Two way ANOVA showed that there was significant difference in cholesterol content between species as well as between seasons. A negative correlation of cholesterol content was observed between size and months of sampling from March to June.Not Availabl

    Health and socioeconomic resource provision for older people in South Asian countries: Bangladesh, India, Nepal, Pakistan and Sri Lanka evidence from NEESAMA

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    Background: The global population is ageing rapidly, with low- and middle-income countries (LMICs) undergoing a fast demographic transition. As the number of older adults in LMICs increases, services able to effectively address their physical and mental health needs will be increasingly important. Objective: We review the health and socioeconomic resources currently available for older people in South Asian countries, Bangladesh, India, Nepal, Pakistan and Sri Lanka, to identify gaps in available resources and assess areas for improvement. Methods: We conducted a search of grey and published literature via Google Search, Compendex, EBSCO, JSTOR, Medline, Ovid, ProQuest databases, Scopus and Web of Science. Data on population demographics, human resources, health funding and social protection for older people were extracted. Local informants were consulted to supplement and verify the data. Results: In the study countries, the number of health professionals with expertise in elderly care was largely unknown, with minimal postgraduate training programmes available in elderly medicine or psychiatry. Older adults are therefore cared for by general physicians, nurses and community health workers, all of whom are present in insufficient numbers per capita. Total average healthcare expenditure was 2.5–5.5% of GDP, with 48.1–72.0% of healthcare costs covered by out-of-pocket payments. Pakistan did not have a social pension; only India and Nepal offered financial assistance to people with dementia; and all countries had disproportionately low numbers of care elderly homes. Conclusions: Inadequate healthcare funding, a shortage of healthcare professionals and insufficient government pension and social security schemes are significant barriers to achieving universal health coverage in LMICs. Governing bodies must expand training pro-grammes for healthcare providers for older adults, alongside increasing social protection to improve access to those in need and to prevent catastrophic health expenditure

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    Not AvailableIn the present study, the administration of peroxidised PUFA was found to aggravate the isoproterenol-induced myocardial infraction in rats, which was evident from the increased level protein and enhanced the release of marker enzymes in the serum of rats given PUFA and isoproterenol. It was also observed that oxidized PUFA in the diet resulted in higher levels of peroxidation and lower levels of antiperoxidative enzymes.Not Availabl

    A Unified Framework for Understanding the Structure and Modifications of Atomically Precise Monolayer Protected Gold Clusters

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    Atomically precise monolayer protected clusters are molecules comprising a few-atom cluster core of a noble metal, typically Au or Ag, surrounded by a protective layer of ligands, exhibiting many special optical, electrical, catalytic, and magnetic properties, and are emerging as important materials in biology, medicine, catalysis, energy conversion and storage, and sensing. The structural diversity of these clusters or aspicules, as we definitively term them, meaning shielded molecules, combining the Greek word <i>aspis</i> (shield) with molecule, is rapidly increasing due to new compositions and modification routes such as ligand-exchange, alloying, or supramolecular functionalization. We present a structural analysis of the most stable cluster of this kind, Au<sub>25</sub>(SR)<sub>18</sub>, and propose a Borromean rings diagram for the cluster, showing its topological configuration of three interlocked (Au<sub>8</sub>S<sub>6</sub>)-rings. This simplified two-dimensional diagram is used to represent its structure and modifications via ligand or metal atom substitution uniquely. We enumerate and name its isomers with two-ligand or metal atom substituents. Among the several structural insights obtained, the identification of the Borromean rings-interlocked configuration in Au<sub>25</sub>(SR)<sub>18</sub> may explain its high geometric stability and indicate a possible general unified structural viewpoint for these clusters without the division between core and staple motifs. On the basis of our structural analysis, we developed a structure-based nomenclature system that can be applied to both describe and understand the structure and modifications of gold thiolate clusters, Au<sub><i>M</i></sub>(SR)<sub><i>N</i></sub>, and is adaptable to the general case of M<sub><i>M</i></sub>(X)<sub><i>N</i></sub> (M, metal and X, ligand). The application of structural analysis and diagrams to Au<sub>38</sub>(SR)<sub>24</sub> and Au<sub>102</sub>(SR)<sub>44</sub>, revealing the possible formation of the cluster core by stacking or growth of rings of metal atoms, is also presented

    Health and socioeconomic resource provision for older people in South Asian countries: Bangladesh, India, Nepal, Pakistan and Sri Lanka evidence from NEESAMA

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    Background The global population is ageing rapidly, with low- and middle-income countries (LMICs) undergoing a fast demographic transition. As the number of older adults in LMICs increases, services able to effectively address their physical and mental health needs will be increasingly important. Objective We review the health and socioeconomic resources currently available for older people in South Asian countries, Bangladesh, India, Nepal, Pakistan and Sri Lanka, to identify gaps in available resources and assess areas for improvement. Methods We conducted a search of grey and published literature via Google Search, Compendex, EBSCO, JSTOR, Medline, Ovid, ProQuest databases, Scopus and Web of Science. Data on population demographics, human resources, health funding and social protection for older people were extracted. Local informants were consulted to supplement and verify the data. Results In the study countries, the number of health professionals with expertise in elderly care was largely unknown, with minimal postgraduate training programmes available in elderly medicine or psychiatry. Older adults are therefore cared for by general physicians, nurses and community health workers, all of whom are present in insufficient numbers per capita. Total average healthcare expenditure was 2.5–5.5% of GDP, with 48.1–72.0% of healthcare costs covered by out-of-pocket payments. Pakistan did not have a social pension; only India and Nepal offered financial assistance to people with dementia; and all countries had disproportionately low numbers of care elderly homes. Conclusions Inadequate healthcare funding, a shortage of healthcare professionals and insufficient government pension and social security schemes are significant barriers to achieving universal health coverage in LMICs. Governing bodies must expand training programmes for healthcare providers for older adults, alongside increasing social protection to improve access to those in need and to prevent catastrophic health expenditure
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