27 research outputs found

    Transparent Oxide MgO Thin Films Prepanred By Reactive Pused Laser Deposition

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    Transparent dielectric thin films of MgO have been deposited on glasssubstrates at different oxygen pressure between (50-300) mbar using a pulsed laserdeposition technique to ablation of Mg target in the presence of oxygen as reactiveatmosphere. Structural, and optical, properties of these films have beeninvestigated. The films crystallize in a cubic structure and X-ray diffractionmeasurements have shown that the polycrystalline MgO films prepared at oxygenpressure (200) mbar and substrate temperature (150°C) with (111) and (002)orientations. The films deposited at oxygen pressure between (150-300) mbar andsubstrate temperature (150°C) exhibited highest optical transmittivity (>80%) andthe direct band gap energy was found to be 5.01 eV at oxygen pressure (200) mbar.The measured of the resistivity of the film prepared at oxygen pressure (200) mbarand substrate temperature (150°C) was 1.45x107Ω cm

    RNA-Seq identifies SPGs as a ventral skeletal patterning cue in sea urchins

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    The sea urchin larval skeleton offers a simple model for formation of developmental patterns. The calcium carbonate skeleton is secreted by primary mesenchyme cells (PMCs) in response to largely unknown patterning cues expressed by the ectoderm. To discover novel ectodermal cues, we performed an unbiased RNA-Seq-based screen and functionally tested candidates; we thereby identified several novel skeletal patterning cues. Among these, we show that SLC26a2/7 is a ventrally expressed sulfate transporter that promotes a ventral accumulation of sulfated proteoglycans, which is required for ventral PMC positioning and skeletal patterning. We show that the effects of SLC perturbation are mimicked by manipulation of either external sulfate levels or proteoglycan sulfation. These results identify novel skeletal patterning genes and demonstrate that ventral proteoglycan sulfation serves as a positional cue for sea urchin skeletal patterning

    Reducing the environmental impact of surgery on a global scale: systematic review and co-prioritization with healthcare workers in 132 countries

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    Abstract Background Healthcare cannot achieve net-zero carbon without addressing operating theatres. The aim of this study was to prioritize feasible interventions to reduce the environmental impact of operating theatres. Methods This study adopted a four-phase Delphi consensus co-prioritization methodology. In phase 1, a systematic review of published interventions and global consultation of perioperative healthcare professionals were used to longlist interventions. In phase 2, iterative thematic analysis consolidated comparable interventions into a shortlist. In phase 3, the shortlist was co-prioritized based on patient and clinician views on acceptability, feasibility, and safety. In phase 4, ranked lists of interventions were presented by their relevance to high-income countries and low–middle-income countries. Results In phase 1, 43 interventions were identified, which had low uptake in practice according to 3042 professionals globally. In phase 2, a shortlist of 15 intervention domains was generated. In phase 3, interventions were deemed acceptable for more than 90 per cent of patients except for reducing general anaesthesia (84 per cent) and re-sterilization of ‘single-use’ consumables (86 per cent). In phase 4, the top three shortlisted interventions for high-income countries were: introducing recycling; reducing use of anaesthetic gases; and appropriate clinical waste processing. In phase 4, the top three shortlisted interventions for low–middle-income countries were: introducing reusable surgical devices; reducing use of consumables; and reducing the use of general anaesthesia. Conclusion This is a step toward environmentally sustainable operating environments with actionable interventions applicable to both high– and low–middle–income countries

    Preparation and Characterization of (Au/n-Sn/Si/Si/Al) MIS Device for Optoelectronic Application

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    SnO2 thin films were prepared by using rapid thermal oxidation (RTO) of Sn at oxidation temperature 873 K and oxidation time 90 sec on semiconductor n-type and p-type silicon substrate. In order to characterize the prepared device, the electrical properties have been measured which revealed that the barrier height is greatly depended on interfacial layer thickness (SiO2). The value of peak response (n-SnO2/SiO2/n-Si) device was 0.16 A/W which is greater than that of (n-SnO2/SiO2/p-Si) device whose value was 0.12 A/W, while the rise time was found to be shorter

    Self-Assembled Ionophores from Isoguanosine: Diffusion NMR Spectroscopy Clarifies Cation's and Anion's Influence on Supramolecular Structure

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    Cation-templated self-assembly of the lipophilic isoguanosine (isoG 1) with different monovalent cations (M+=Li+, Na+, K+, NH4+, and Cs+) was studied in solvents of different polarity by using diffusion NMR spectroscopy. Previous studies that did not use diffusion NMR techniques concluded that isoG 1 forms both pentamers (isoG 1)5M+ and decamers (isoG 1)10M+ in the presence of alkali-metal cations. The present diffusion NMR studies demonstrate, however, that isoG 1 does not form (isoG 1)5M+ pentamers. In fact, the diffusion NMR data indicates that both doubly charged decamers of formula (isoG 1)102 M+ and singly charged decamers, (isoG 1)10M+, are formed with lithium, sodium, potassium, and ammonium tetraphenylborate salts (LiB(Ph)4, KB(Ph)4, NaB(Ph)4 and NH4B(Ph)4), depending on the isoG 1:salt stoichiometry of the solution. In the presence of CsB(Ph)4, isoG 1 affords only the singly charged decamers (isoG 1)10Cs+. By monitoring the diffusion coefficient of the B(Ph)4- ion in the different mixtures of solvents, we also concluded that the anion is more strongly associated to the doubly charged decamers (isoG 1)102 M+ than to the singly charged decamers (isoG 1)10M+. The (isoG 1)102 M+ species can, however, exist in solution without the mediation of the anion. This last conclusion was supported by the finding that the doubly charged decamers (isoG 1)102 M+ also prevail in 1:1 CD3CN:CDCl3, a solvent mixture in which the B(Ph)4- ion does not interact significantly with the self-assembled complex. These diffusion measurements, which have provided new and improved structural information about these decameric isoG 1 assemblies, demonstrate the utility of combining diffusion NMR techniques with conventional NMR methods in seeking to characterize labile, multicomponent, supramolecular systems in solution, especially those with high symmetry

    Noncovalent synthesis in aqueous solution and spectroscopic characterization of multi-porphyrin complexes

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    The interactions of the tetracationic meso-tetrakis(N-methyl-4-pyridyl)porphyrin (H(2)TMPyP) and its metallo derivatives (MTMPyP) (where M=copper(II), zinc(II), and gold(III) with the octa-anionic form (at neutral pH) of 5,11,17,23-tetrasulfonato-25,26,27,28-tetrakis(hydroxycarbonylmethoxy)calix[4]arene (C(4)TsTc) lead to a series of complex species whose stoichiometry and porphyrin sequence can be easily tuned. Crystallographic, spectroscopic, and diffusion NMR studies converge towards a common picture in which a central 1:4 porphyrin/calixarene unit serves as a template for the formation of more complex species. These species arise by successive, stepwise addition of single porphyrin molecules above and below the plane of the 1:4 central core to ultimately give a 7:4 complex. Noticeably, the stoichiometry of the various complex species corresponds to the actual concentration ratio of porphyrins and calixarenes in solution allowing the stoichiometry of these species to be easily tuned. This behavior and the remarkable stability of these species allow homo-porphyrin and hetero-(metallo)porphyrin species to be formed with control of not only the stoichiometry but also the sequence of the porphyrin array. The flexibility and ease of this approach permit, in principle, the design and synthesis of porphyrin arrays for predetermined purposes. For example, we have shown that it is very easy to design and obtain mixed porphyrin species in which a foreseen photoinduced electron-transfer is indeed observed
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