1,812 research outputs found

    Band gap energy modifications observed in trivalent In substituted nanocrystalline SnO2

    Get PDF
    The effect of In doping concentration on the optical band gap of nano-SnO2 is investigated as a function of calcination temperature. Changes in the band gap explain the room temperature H-2 gas sensing of doped nano-SnO2. The band gap was found to be lower than those reported for SnO2 (3.6 eV) from 2.55 to 3.43 eV and may be explained by the presence of nonequilibrium oxygen vacancies in the oxide lattice and band bending effects at the nanoscale

    Cell Membrane Penetration without Pore Formation : Chameleonic Properties of Dendrimers in Response to Hydrophobic and Hydrophilic Environments

    Get PDF
    The mechanism by which cell-penetrating peptides and antimicrobial peptides cross plasma membranes is unknown, as is how cell-penetrating peptides facilitate drug delivery, mediating the transport of small molecules. Once nondisruptive and nonendocytotic pathways are excluded, pore formation is one of the proposed mechanisms, including toroidal, barrel-stave, or carpet models. Spontaneous pores are observed in coarse-grained simulations and less often in molecular dynamics simulations. While pores are widely assumed and inferred, there is no unambiguous experimental evidence of the existence of pores. Some recent experimental studies contradict the mechanistic picture of pore formation, however, highlighting the possibility of a direct translocation pathway that is both nondisruptive and nonendocytotic. In this work, a model is proposed a model for peptide (linear and dendritic) translocation which does not require the presence of pores and which potentially accords with such experiments. It is suggested that a charged peptide, as it experiences an increasingly hydrophobic environment within the membrane surface, can utilize a proton chain transfer mechanism to shed its protons to counter ions or potentially phospholipid head groups in the membrane skin region, thereby becoming compatible with the hydrophobic interior of the membrane. This increases the likelihood to move into the highly hydrophobic core of the membrane and ultimately reach the opposite leaflet to re-acquire protons again, suggesting a potential "chameleon" mechanism for non-disruptive and non-endocytotic membrane translocation. The molecular dynamics simulations reveal stability of peptide bridges joining two membrane leaflets and demonstrate that this can facilitate cross-membrane transport of small drug molecules.Peer reviewe

    Transparent ferromagnetic and semiconducting behavior in Fe-Dy-Tb based amorphous oxide films

    Get PDF
    We report a class of amorphous thin film material comprising of transition (Fe) and Lanthanide metals (Dy and Tb) that show unique combination of functional properties. Films were deposited with different atomic weight ratio (R) of Fe to Lanthanide (Dy + Tb) using electron beam co-evaporation at room temperature. The films were found to be amorphous, with grazing incidence x-ray diffraction and x-ray photoelectron spectroscopy studies indicating that the films were largely oxidized with a majority of the metal being in higher oxidation states. Films with R = 0.6 were semiconducting with visible light transmission due to a direct optical band-gap (2.49 eV), had low resistivity and sheet resistance (7.15 × 10−4 Ω-cm and ~200 Ω/sq respectively), and showed room temperature ferromagnetism. A metal to semiconductor transition with composition (for R \u3c 11.9) also correlated well with the absence of any metallic Fe0oxidation state in the R = 0.6 case as well as a significantly higher fraction of oxidized Dy. The combination of amorphous microstructure and room temperature electronic and magnetic properties could lead to the use of the material in multiple applications, including as a transparent conductor, active material in thin film transistors for display devices, and in spin-dependent electronics

    Accuracy of screening tools for Pap smears in general practice

    Get PDF
    Background: Data extraction tools (DETs) are increasingly being used for research and audit of general practice, despite their limitations. Objective: This study explores the accuracy of Pap smear rates obtained with a DET compared to that of the Pap smear rate obtained with a manual file audit. Method: A widely available DET was used to establish the rate of Pap smears in a large multi-general practice (multi-GP) in regional New South Wales followed by a manual audit of patient files. The main outcome measure was identification of possible discrepancies between the rates established. Results: The DET used significantly underestimated the level of cervical screening compared to the manual audit. In some instances, the patient file contained phone/specialist record of Pap smear conducted elsewhere, which accounted for the failure of the DET to detect some smears. Those patients who had Pap smears whose pathology codes differed between time intervals, i.e. from different pathology providers or from within the same provider but using a different code, were less likely to have had their most recent Pap smear detected by the DET (p \u3c 0.001). Conclusion: Data obtained from DETs should be used with caution as they may not accurately reflect the rate of Pap smears from electronic medical records

    Enhancing the low temperature hydrogen sensitivity of nanocrystalline SnO2 as a function of trivalent dopants

    Get PDF
    The effect of different indium doping concentrations on the room temperature hydrogen sensitivity of nano-SnO2 is investigated. The role of calcination temperature on the surface morphology, phase transformation, and subsequent impact on the gas sensing behavior of nanocrystalline doped SnO2 is presented. Differences in grain growth with varying doping amount give an explanation for enhanced sensing that is not always so obvious. Variation in the charge carrier density for indium doped nanocrystalline SnO2 is calculated as a function of indium concentration in the tin oxide lattice structure. The charge carrier density is correlated to the involved surface species of doped nanocrystalline SnO2 upon hydrogen gas exposure using Fourier transform infrared spectroscopy

    Admission profile and discharge outcomes for infants aged less than 6 months admitted to inpatient therapeutic care in 10 countries. A secondary data analysis.

    Get PDF
    Evidence on the management of acute malnutrition in infants aged less than 6 months (infants <6mo) is scarce. To understand outcomes using current protocols, we analysed a sample of 24 045 children aged 0-60 months from 21 datasets of inpatient therapeutic care programmes in 10 countries. We compared the proportion of admissions, the anthropometric profile at admission and the discharge outcomes between infants <6mo and children aged 6-60 months (older children). Infants <6mo accounted for 12% of admissions. The quality of anthropometric data at admission was more problematic in infants <6mo than in older children with a greater proportion of missing data (a 6.9 percentage point difference for length values, 95% CI: 6.0; 7.9, P < 0.01), anthropometric measures that could not be converted to indices (a 15.6 percentage point difference for weight-for-length z-score values, 95% CI: 14.3; 16.9, P < 0.01) and anthropometric indices that were flagged as outliers (a 2.7 percentage point difference for any anthropometric index being flagged as an outlier, 95% CI: 1.7; 3.8, P < 0.01). A high proportion of both infants <6mo and older children were discharged as recovered. Infants <6mo showed a greater risk of death during treatment (risk ratio 1.30, 95% CI: 1.09; 1.56, P < 0.01). Infants <6mo represent an important proportion of admissions to therapeutic feeding programmes, and there are crucial challenges associated with their care. Systematic compilation and analysis of routine data for infants <6mo is necessary for monitoring programme performance and should be promoted as a tool to monitor the impact of new guidelines on care
    • …
    corecore