Mesoporous TiO2 coating on carbon–sulfur cathode for high capacity Li–sulfur battery

In this paper, a meso-porous TiO₂ (titania) coating is shown to effectively protect a carbon–sulfur composite cathode from polysulfide dissolution. The cathode consisted of a sulfur impregnated carbon support coated with a few microns thick mesoporous titania layer. The carbon–sulfur cathode is made using activated carbon powder (ACP) derived from biomass. The mesoporous titania coated carbon–sulfur cathodes exhibit a retention capacity after 100 cycles at C/3 rate (433 mA g ⁻¹) and stabilized at a capacity around 980 mA h g⁻¹. The electrochemical impedance spectroscopy (EIS) of the sulfur cathodes suggests that the charge transfer resistance at the anode, (R_act) is stable for the titania coated sulfur electrode in comparison to a continuous increase in R_act for the uncoated electrode implying mitigation of polysulfide shuttling for the protected cathode. Stability in the cyclic voltammetry (CV) data for the first 5 cycles further confirms the polysulfide containment in the titania coated cathode while the uncoated sulfur electrode shows significant irreversibility in the CV with considerable shifting of the voltage peak positions. Raman spectroscopy and X-ray photoelectron spectroscopy (XPS) studies confirm the adsorption of soluble polysulfides by mesoporous titania.

Mesoporous TiO₂ coating on carbon–sulfur cathode with simple electrical contact for high capacity Li–S battery.     

Physical and genetic mapping of barley (Hordeum vulgare) germin-like cDNAs

Germin with oxalate oxidase and superoxide dismutase activity is a homohexamer of six manganese-containing interlocked beta-jellyroll monomers with extreme resistance to heat and proteolytic degradation [Woo, E.-J., Dunwell, J. M., Goodenough, P. W., Marvier, A. C. & Pickersill, R. W. (2000) Nat. Struct. Biol. 7, 1036-1038]. This structure is conserved in germin-like proteins (GLPs) with other enzymatic functions and characteristic for proteins deposited in plant cell walls in response to pathogen attack and abiotic stress. Comparative nucleotide and amino acid sequence analyses of 49,610 barley expressed sequence tags identified 124 germin and germin-like cDNAs, which distributed into five subfamilies designated HvGER-I to HvGER-V. Representative cDNAs for these subfamilies hybridized to 67 bacterial artificial chromosome (BAC) clones from a library containing 6.3 genomic equivalents. Twenty-six BAC clones hybridized to the subfamily IV probe and identified a gene-rich region including clone 418E1 of 96 kb encoding eight GLPs (i.e., 1 gene per 12 kb). This BAC clone lacked highly repeated sequences and mapped to the subtelomeric region of the long arm of chromosome 4(4H). Among the six genes of the contig expressed in leaves, one specifies a protein known to be associated with papilla formation in the epidermis upon powdery mildew infection. Three structural genes for oxalate oxidase are present in subfamily I and eight GLPs of various functions in the other subfamilies. These genes map at loci in chromosomes 1(7H), 2 (2H), 3(3H), 4(4H), and 7(5H). Some are present on a single BAC clone. The results are discussed in relation to cereal genome organization.     

Clinical usefulness of the framingham cardiovascular risk profile beyond its statistical performance: the tehran lipid and glucose study

The utility of a risk function in clinical practice is an important concept that has received insufficient attention. The authors evaluated the clinical usefulness of the Framingham risk function (FRF) for cardiovascular disease in a Middle Eastern population (2,640 men and 3,584 women aged 30-74 years) free of cardiovascular disease at baseline in 1999. They calculated the net benefit fraction for treatment of subjects with an estimated 10-year risk of ≥10% and also ≥20%, where the net benefit fraction is a weighted sum of true-positive and false-positive rates divided by incidence, as estimated by Kaplan-Meier analysis. The authors drew a decision curve by plotting the net benefit fraction against a wide range of risk thresholds for treatment. The cumulative incidence of cardiovascular disease was 7.6% and 12.3% in women and men, respectively. The FRF had a C index of 0.832 in women and 0.785 in men with a reasonable calibration. On the basis of the net benefit fraction, about 50% of the incidence in men and women could be appropriately treated by using the 10% threshold; however, the FRF was not useful at the 20% threshold, especially in women. In both genders, usefulness of the FRF was as good as the function derived directly from Tehrani data with the same variables; however, it could be useful in low thresholds for treatment.     

Fluoroquinolone resistance in clinical isolates of Streptococcus pneumoniae from Asian countries: ANSORP study

Seventeen clinical isolates of Streptococcus pneumoniae showing reduced susceptibility to ciprofloxacin (MIC >/= 4 micro g/ml) collected from eight different Asian countries were analyzed by antimicrobial susceptibility, serotyping, pulsed-field gel electrophoresis (PFGE), and DNA sequencing of the quinolone resistance-determining regions (QRDRs) in gyrA, gyrB, parC, and parE. All isolates but one showed more than one amino acid alteration in QRDRs of four responsible genes. Ile460 --> Val in parE was the most common mutation. Data suggest that Lys137 --> Asn in parC may be a primary step in the development of high-level and multiple FQ resistance. An additional mutation of Ser81 --> Phe in gyrA resulted in high-level resistance to ciprofloxacin, levofloxacin, and gatifloxacin, whereas Ser79 --> Phe in parC may exert an important role in the development of moxifloxacin resistance. Two novel amino acid changes in gyrB, Ala390 --> Val and Asn423 --> Thr, were found. Data from PFGE suggest an introduction and local spread of multiple resistant Spain(23F)-1 clone in Hong Kong, but isolates from other Asian countries were not related to this clone.