645 research outputs found

    Synthesis and crystallographic characterization of new heterotrinuclear oxo-centered complex

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    New oxo-centered trinuclear mixed-metal complex, of [Fe2ZnO(CHCl2CO2)6(CHCl2CO2)3].NO3 was synthesized by the direct reaction between metal nitrates and dichloroacetic acid. These compounds have a typical μ3-oxo trinuclear structure: (a) three metal atoms are situated in the apexes of the equilateral triangle; (b) μ3-oxygen atom and six dichloroacetate ligands fulfil the bridge functions and (c) the monodentate CHCl2CO2 ligands complete the octahedral geometry of the metal ions. This complex were characterized by elemental analyses (CHN), atomic absorption spectroscopy and spectral (IR, electronic) studies. This is new types of oxo-bridged mixed-metal complex in which the carboxylate ligand is dichloroacetic acid. The UV spectra of the complex exhibited strong bands in the region 213 and 257 nm which are related to the (π → π*) and (n → π*) transitions of the CHCl2CO2 ligands, respectively. The IR spectra of this compound showed two strong stretching vibrations bands, indicating a bridging coordination mode of the carboxylic group by presence of νasym (M2M'O) vibrations of the ligand in the infrared spectra.               KEY WORDS: Oxo-centered, Trinuclear complexes, Carboxylic ligand, Crystallographic data, IR spectra Bull. Chem. Soc. Ethiop. 2018, 32(3), 491-500.DOI: https://dx.doi.org/10.4314/bcse.v32i3.

    Microwave-promoted solvent free one-pot synthesis of triazolo[1,2-a] indazole-triones catalyzed by silica-supported La0.5Ca 0.5CrO3 nanoparticles as a new and reusable perovskite-type oxide

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    Microwave assisted solvent free synthesis of triazolo[1,2-a]indazole-1,3,8-triones through one-pot three-component reaction of dimedone, phenyl urazole and aromatic aldehydes is presented. The reaction process was catalyzed by La0.5Ca0.5CrO3 and silica-supported La0.5Ca0.5CrO3 nanoparticles as new perovskite-type catalysts. The nano catalyst was studied by XRD, SEM and IR characterization tools. Some advantages of the proposed approach include high yield, being eco-friendly, procedure convenience and reusability of the catalyst.               KEY WORDS: One-pot reaction, Triazolo[1,2-a]indazole trione, Perovskite oxide, Nano catalyst, Microwave, Solvent-free Bull. Chem. Soc. Ethiop. 2018, 32(2), 239-248.DOI: https://dx.doi.org/10.4314/bcse.v32i2.

    Dead-End Microfiltration of Rough Non-Alcoholic Beer by Different Polymeric Membranes

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    Clarification of rough nonalcoholic beer using microfiltration as an al-ternative to conventional filtration with filter aids presents scientific and technical challenges for the brewing industry. An experimental pilot plant was used to evaluate the permeability and selectivity of polymeric mem-branes in the clarification process. Cellulose acetate (CA) with pore sizes of 0.2, 0.45, 0.8, and 1.2 μm, together with cellulose nitrate (CN), nylon (NY), and polytetrafluoroethylene (PTFE) with a pore size of 0.45 μm, were used at transmembrane pressures (TMP) of 1.0 and 2.0 bar. The data cor-roborated that the flux values of the CA, CN, and NY membranes were al-most the same and reduced drastically, whereas PTFE was not permeable at 1.0 bar and its flux at 2.0 bar increased at the beginning and decreased after reaching a maximum. At both TMP, the CN membrane displayed the highest rejection of suspended particles and haze-active proteins, while re-tention of polyphenols and color were highest for the NY membrane. The lower selectivity of the PTFE membrane can be attributed to its hydropho-bicity and less interaction with the hydrophilic haze-active proteins. The results confirmed that by increasing the pore size of CA membranes the separation factor of the sensitive proteins and suspended particles decreased and permeability increased

    Interest in bariatric surgery among obese patients with obstructive sleep apnea

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    BACKGROUND: Standard obstructive sleep apnea (OSA) therapies are poorly tolerated. Bariatric surgery is a potential alternative but the level of interest in this intervention among OSA patients is unknown. OBJECTIVES: Determine the proportion of OSA patients who would be interested in bariatric surgery. SETTING: Sleep clinics, United States. METHODS: Consecutive adult patients with untreated severe OSA and a body mass index of 35-45 kg/m2 were approached. Patients at low perioperative risk and no urgent indication for OSA treatment were invited to a separate informational visit about bariatric surgery as primary treatment for OSA. RESULTS: Of 767 eligible patients, 230 (30.0%) were not at low perioperative risk, 49 (6.4%) had drowsy driving, and 16 (2.1%) had no insurance coverage for bariatric surgery. Of the remaining 482 patients, over one third (35.5%) were interested in bariatric surgery. Surgical interest was 47.2% in women versus 27.6% in men (

    An Automatic Digital Terrain Generation Technique for Terrestrial Sensing and Virtual Reality Applications

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    The identification and modeling of the terrain from point cloud data is an important component of Terrestrial Remote Sensing (TRS) applications. The main focus in terrain modeling is capturing details of complex geological features of landforms. Traditional terrain modeling approaches rely on the user to exert control over terrain features. However, relying on the user input to manually develop the digital terrain becomes intractable when considering the amount of data generated by new remote sensing systems capable of producing massive aerial and ground-based point clouds from scanned environments. This article provides a novel terrain modeling technique capable of automatically generating accurate and physically realistic Digital Terrain Models (DTM) from a variety of point cloud data. The proposed method runs efficiently on large-scale point cloud data with real-time performance over large segments of terrestrial landforms. Moreover, generated digital models are designed to effectively render within a Virtual Reality (VR) environment in real time. The paper concludes with an in-depth discussion of possible research directions and outstanding technical and scientific challenges to improve the proposed approach

    Economic evaluation of End Stage Renal Disease treatments in Iran

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    Background: End-stage Renal Disease is considered a health problem due to the high prevalence and economic burden on society and the health system. This study utilizes a cost-utility analysis to evaluate the costs and outcomes of the Iranian End Stage Renal Disease patients. Methods: A Markov model-based economic evaluation with a societal perspective, and a lifetime horizon performed to quantify the costs and health-related outcomes in terms of QALY. Direct medical costs obtained from hospital billing and medical records and direct non-medical costs, and indirect costs derived from interviews with patients. Three policy options, the hemodialysis, peritoneal dialysis and kidney transplantation were compared. Most of the Transplants from deceased and rest were from Live Related Donors. One-way and probabilistic sensitivity analyses were performed to study uncertainty. Results: Annual average cost of hemodialysis is 13477 cost of peritoneal dialysis is 12865, and cost of Transplantation is 16450.The Transplantation arm gained 9.43 QALY compared with peritoneal dialysis and hemodialysis with 6.95 and 6.04 QALY respectively. When Transplantation was compared with peritoneal dialysis, Incremental Cost-Effectiveness Ratio was 1744 per QALY. ICER value suggests that Transplantation is cost-effective compared with peritoneal dialysis at a willingness-to-pay threshold of 12,400, and hemodialysis was dominated. Conclusion: This study suggests that kidney transplantation is a better option over hemodialysis and peritoneal dialysis. We conclude that serious efforts ought to be made to foster potential brain-dead donors and altruistic kidney donation and promote peritoneal dialysis as a superior alternative to hemodialysis for eligible patients. © 2019 INDIACLE

    Shape dependent protein‐induced stabilization of gold nanoparticles: From a protein corona perspective

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    Gold nanoparticles (AuNPs) are promising materials for many bioapplications. However, upon contacting with biological media, AuNPs undergo changes. The interaction with proteins results in the so-called protein corona (PC) around AuNPs, leading to the new bioidentity and optical properties. Understanding the mechanisms of PC formation and its functions can help us to utilise its benefits and avoid its drawbacks. To date, most of the previous works aimed to understand the mechanisms governing PC formation and focused on the spherical nanoparticles, although non-spherical nanoparticles are designed for a wide range of applications in biosensing. In this work, we investigated the differences in PC formation on spherical and anisotropic AuNPs (nanostars in particular) from the joint experimental (extinction spectroscopy, zeta potential and surface-enhanced Raman scattering [SERS]) and computational methods (the finite element method and molecular dynamics [MD] simulations). We discovered that protein does not fully cover the surface of anisotropic nanoparticles, leaving SERS hot-spots at the tips and high curvature edges ‘available’ for analyte binding (no SERS signal after pre-incubation with protein) while providing protein-induced stabilization (indicated by extinction spectroscopy) of the AuNPs by providing a protein layer around the particle's core. The findings are confirmed from our MD simulations, the adsorption energy significantly decreases with the increased radius of curvature, so that tips (adsorption energy: 2762.334 kJ/mol) would be the least preferential binding site compared to core (adsorption energy: 11819.263 kJ/mol). These observations will help the development of new nanostructures with improved sensing and targeting ability

    Burden of mild haemophilia A: Systematic literature review

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    Introduction Although the clinical manifestations of severe haemophilia A (HA) are well studied, the challenges, if any, of living with mild HA are not clearly delineated to date. Aim To assess available evidence of clinical risks and societal/economic impacts of disease in adult patients with mild HA using a systematic literature review. Methods Prespecified study selection criteria were applied in a comprehensive literature search. Included studies varied in design and reported outcomes of interest for adults (>= 13 years of age) with mild HA. Results Seventeen studies with a total of 3213 patients met eligibility criteria (published or presented in English, 1966-2017). Most studies were observational, and the outcomes reported were too sparse and dissimilar to support a formal meta-analysis. Mean annual bleeding rates ranged from 0.44 to 4.5 episodes per patient per year. Quality of life (QoL; SF-36 General Health) was impacted compared to healthy controls. Health care costs and productivity were seldom assessed and no robust comparisons to healthy controls were available. Conclusion Quantifying outcomes for adult patients with mild HA remains challenging, with estimates of key QoL and cost data often based on small data sets and without comparison to population norms. Therefore, the clinical impact of mild haemophilia may be under-represented and unmet needs may remain unaddressed. As paradigm-changing therapies for HA emerge, stronger knowledge of mild HA can guide the development of care options that minimize burden and enhance the QoL for this segment of the haemophilia community, and for the haemophilia community in totality
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