2,484 research outputs found
Synthesis of high performance ceramic fibers by chemical vapor deposition for advanced metallics reinforcing
The chemical vapor deposition (CVD) synthesis of fibers capable of effectively reinforcing intermetallic matrices at elevated temperatures which can be used for potential applications in high temperature composite materials is described. This process was used due to its advantage over other fiber synthesis processes. It is extremely important to produce these fibers with good reproducible and controlled growth rates. However, the complex interplay of mass and energy transfer, blended with the fluid dynamics makes this a formidable task. The design and development of CVD reactor assembly and system to synthesize TiB2, CrB, B4C, and TiC fibers was performed. Residual thermal analysis for estimating stresses arising form thermal expansion mismatch were determined. Various techniques to improve the mechanical properties were also performed. Various techniques for improving the fiber properties were elaborated. The crystal structure and its orientation for TiB2 fiber is discussed. An overall view of the CVD process to develop CrB2, TiB2, and other high performance ceramic fibers is presented
Synthesis, structural characterization and biological properties of cyclometalated iridium(iii) complexes containing 1,2,5]-thiadiazolo-3,4-f]-1,10]-phenanthroline
Two cationic iridium(iii) complexes, Ir(ppy)(2)((tdzp))](+)(1) and Ir(bhq)(2)((tdzp))](+)(2) {ppy = 2-phenylpyridine, bhq = benzoh]quinoline, tdzp = 1,2,5]-thiadiazolo-3,4-f]-1,10]-phenanthroline}, have been synthesized and structurally characterized. The molecular structures of the iridium complexes have been confirmed by single-crystal X-ray structure determination. Extensive hydrogen bonding between lattice water molecules, solvated methanol, and chloride anions is observed in the crystal structure of complex1, which leads to the formation of 1D polymeric cyclic hybrid water-chloride-methanol clusters. The complexes show different photophysical properties in different solvents. The experimental photo-physical properties of the synthesized iridium(iii) complexes match well with the theoretically calculated results obtained by density functional theory (DFT) and time-dependent density functional theory (TD-DFT) studies. The HOMO of complexes1and2is restricted on the iridium and cyclometalated aromatic ligands, while the LUMO, LUMO+1, and LUMO+2 are primarily restricted on the polypyridyl tdzp ligand. The interaction of the complexes with calf thymus DNA (CT-DNA) was investigated by absorption titration and emission titration experiments. Furthermore, the cytotoxicity and cellular localization properties of these complexes towards HeLa cells have been investigated
Efficacy of sodium feredetate versus ferrous sulfate in iron deficiency anemia in preganant women
Background: The main aim of the study was to determine the efficacy of Sodium Feredetate with Ferrous Sulfate in treatment of iron deficiency anemia in pregnant women. Rise in hemoglobin after one and two months of treatment with respective drugs and their side effects.Methods: Prospective randomized study carried out between Jan 2008-July 2009 at Government Tertiary Care Level Hospital OBG Department in Mangalore on 74 pregnant women with anemia.Results: Sodium feredetate (Na Fe EDTA) in iron deficiency anemia led to a significant and rapid rise in hemoglobin levels than that with ferrous sulfate in our study.Conclusions: Sodium Feredetate in iron deficiency anemia led to a significant and rapid rise in hemoglobin levels than that with Ferrous Sulfate and also associated with minimal or no side effects
Computational Fluid Dynamics based redesign of the Magnetically Levitated Blood Shearing Device for Hemolysis Predictions
Annular Couette type blood shearing devices have been used for analysis of blood damage related to device induced shear stress. Two important factors in predicting cell damage are the magnitude of stress and the duration of exposure to the stress. Several previous devices for blood damage analysis consist of concentric cylinders with one cylinder rotating and the other held stationary. This generates a Couette flow between the cylinders. In a typical apparatus, the shear stress can be controlled by varying the rotation of the inner cylinder and the exposure time can be controlled by controlling the axial velocity of the fluid through the device. The higher the rotational speed the higher the magnitude shear stress. However, apparati are susceptible to a flow instability at high rotational speeds. This flow instability is characterized by toroidal vortices and may be predicted by the Taylor number, which is related to the fluid viscosity, gap and rotational speed. If the critical Taylor number is exceeded, Taylor vortices will exist. Taylor vortices are undesirable because blood cells may become entrapped in these vortices and increase exposure time thus leading to distorted hemolysis data. Because shear stress is also a function of the gap and rotational speed, the avoidance of Taylor vortices places limits the shear stress and exposure times that can be achieved in this type of a device. Changing the gap size and shape affects the formation of Taylor vortices. In this study several variations of the gap shape and size of the flow path of a blood shearing device are investigated numerically in order to find the geometry that has a physiologically relevant range of shear stress and exposure time while avoiding Taylor vortices. The proposed design will be used in future studies to study the effect of shear stress on the blood for a certain exposure time
Estrogen activation of microglia underlies the sexually dimorphic differences in Nf1 optic glioma-induced retinal pathology
Children with neurofibromatosis type 1 (NF1) develop low-grade brain tumors throughout the optic pathway. Nearly 50% of children with optic pathway gliomas (OPGs) experience visual impairment, and few regain their vision after chemotherapy. Recent studies have revealed that girls with optic nerve gliomas are five times more likely to lose vision and require treatment than boys. To determine the mechanism underlying this sexually dimorphic difference in clinical outcome, we leveraged Nf1 optic glioma (Nf1-OPG) mice. We demonstrate that female Nf1-OPG mice exhibit greater retinal ganglion cell (RGC) loss and only females have retinal nerve fiber layer (RNFL) thinning, despite mice of both sexes harboring tumors of identical volumes and proliferation. Female gonadal sex hormones are responsible for this sexual dimorphism, as ovariectomy, but not castration, of Nf1-OPG mice normalizes RGC survival and RNFL thickness. In addition, female Nf1-OPG mice have threefold more microglia than their male counterparts, and minocycline inhibition of microglia corrects the retinal pathology. Moreover, pharmacologic inhibition of microglial estrogen receptor-β (ERβ) function corrects the retinal abnormalities in female Nf1-OPG mice. Collectively, these studies establish that female gonadal sex hormones underlie the sexual dimorphic differences in Nf1 optic glioma–induced retinal dysfunction by operating at the level of tumor-associated microglial activation
Cost-Utility Analysis of Venous Thromboembolism Prophylaxis Strategies for People Undergoing Elective Total Hip and Total Knee Replacement Surgeries in the English National Health Service
Background: Major orthopedic surgery, such as elective total hip replacement (eTHR) and elective total knee replacement (eTKR), are associated with a higher risk of venous thromboembolism (VTE) than other surgical procedures. Little is known, however, about the cost-effectiveness of VTE prophylaxis strategies in people undergoing these procedures. Aim: The aim of this work was to assess the cost-effectiveness of these strategies from the English National Health Service perspective to inform NICE guideline (NG89) recommendations. Materials and Methods: Cost-utility analysis, using decision modeling, was undertaken to compare 15 VTE prophylaxis strategies for eTHR and 12 for eTKR, in addition to “no prophylaxis” strategy. The analysis complied with the NICE Reference Case. Structure and assumptions were agreed with the guideline committee. Incremental net monetary benefit (INMB) was calculated, vs. the model comparator (LMWH+ antiembolism stockings), at a threshold of £20,000/quality-adjusted life-year (QALY) gained. The model was run probabilistically. Deterministic sensitivity analyses (SAs) were undertaken to assess the robustness of the results. Results: The most cost-effective strategies were LMWH for 10 days followed by aspirin for 28 days (INMB = £530 [95% CI: -£784 to £1,103], probability of being most cost-effective = 72%) for eTHR, and foot pump (INMB = £353 [95% CI: -£101 to £665]; probability of being most cost-effective = 18%) for eTKR. There was considerable uncertainty regarding the cost-effectiveness ranking in the eTKR analysis. The results were robust to change in all SAs. Conclusions: For eTHR, LMWH (standard dose) for 10 days followed by aspirin for 28 days is the most cost-effective VTE prophylaxis strategy. For eTKR, the results are highly uncertain but foot pump appeared to be the most cost-effective strategy, followed closely by aspirin (low dose). Future research should focus on assessing cost-effectiveness of VTE prophylaxis in the eTKR population.Peer reviewe
Development of a context-specific search engine, an executive information system, and a novel www ready external cost model
NJPIES is associated with Information Ecology and Sustainability, a holistic approach to environmental data collection, compilation, integration and provision that puts people, not technology, at the center of the environmental information world.
The first main goal of this project was to develop an algorithm and associated computer-based tool that could perform a lifecycle cost analysis for a model system. The application developed solved the primary problem associated with the lifecycle cost analysis of a product: it accounted for all costs (e.g., environmental costs such as ecological costs and health costs associated with emissions) of the activity. A lifecycle cost analysis attempts to identify, measure, and quantify the social costs of human activities such as manufacturing that are not considered with traditional accounting systems. The application developed will quantify, monetize, and rank the damage or external costs to the environment of certain types of emissions. We developed a preliminary algorithm and software and implemented it at two plants: load assembly pack operation at Iowa Army Ammunition Plant (IAAAP) and Armtec, a manufacturer of combustible cartridge cases.
The second main goal of this project is to act as a credible information-clearing house in pollution prevention (P2) and related environmental matters, and to educate the public and keep them aware of facts taking place in the environmental/manufacturing world. Intelligent search engines have been built to access these huge databases in human readable format and correlate the data to various reports providing information on the environmentally hazardous chemicals, releases, and facilities in different regions.
The third main goal is the enhancement of EnviroDaemon with a hierarchical information search interface. This project describes some approaches that locate information according to syntactic criteria, augmented by pragmatic aspects like the utilization of information in a certain context. The main emphasis of this project lies in the treatment of structured knowledge, where essential aspects about the topic of interest are encoded not only by the individual items, but also by their relationships among each other. Benefits of this approach are enhanced precision and approximate search in an already focused, context specific search engine for the environment
Fluorophore tagged mixed ligand copper(II) complexes: synthesis, structural characterization, protein binding, DNA cleavage and anticancer activity
Two fluorophore tagged copper(II) complexes Cu(phen)(L)(ClO4)(2)] (1) and Cu(bpy)(L)(H2O)(ClO4)](ClO4) (2), (where L=2-amino-1H-benzode]isoquinoline-1,3-(2H)dione (L), phen=1,10-phenanthroline and bpy=2,2 `-bipyridine) have been synthesized and structurally characterized. Structures of the copper complexes 1 and 2 were confirmed by single-crystal X-ray structure determination. The coordination geometry around the copper center of complexes 1 and 2 is distorted octahedral. The plasmid DNA cleavage activity of the complexes has been investigated by agarose gel electrophoresis and the study reveals that both the complexes have high plasmid DNA photo-cleavage activity. The binding interaction ability of the metal complexes with bovine serum albumin (BSA) was investigated using fluorescence spectroscopy. The cytotoxicity of the complexes has been evaluated by MTT (3-4,5-dimethylthiazole-2-yl]-2,5-diphenyltetrazolium bromide) assay against A549 (adenocarcinoma human alveolar basal epithelial cells) and MCF-7 (breast cancer cell line) cell lines in comparison with cis-platin. Complexes 1 and 2 have exhibited better cytotoxic activity than cis-platin against A549 and MCF-7 cell lines. The cellular uptake study and localization of the complexes within the cells have been investigated by fluorescence microscopy. The cell staining and flow cytometry experiments suggest that complexes induce an apoptotic mode of cell death
Identification of a Novel Recycling Sequence in the C-tail of FPR2/ALX Receptor: Association with Cell Protection from Apoptosis
Formyl-peptide receptor type 2 (FPR2; also called ALX because it is the receptor for lipoxin A4) sustains a variety of biological responses relevant to the development and control of inflammation, yet the cellular regulation of this G-protein-coupled receptor remains unexplored. Here we report that, in response to peptide agonist activation, FPR2/ALX undergoes β-arrestin-mediated endocytosis followed by rapid recycling to the plasma membrane. We identify a transplantable recycling sequence that is both necessary and sufficient for efficient receptor recycling. Furthermore, removal of this C-terminal recycling sequence alters the endocytic fate of FPR2/ALX and evokes pro-apoptotic effects in response to agonist activation. This study demonstrates the importance of endocytic recycling in the anti-apoptotic properties of FPR2/ALX and identifies the molecular determinant required for modulation of this process fundamental for the control of inflammation
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