Block copolymer self-assembly is an innovative technology capable of patterning technologically relevant substrates with nanoscale precision for a range of applications from integrated circuit fabrication to tissue interfacing, for example. In this article, we demonstrate a microwave-based method of rapidly inducing order in block copolymer structures. The technique involves the usage of a commercial microwave reactor to anneal block copolymer films in the presence of appropriate solvents, and we explore the effect of various parameters over the polymer assembly speed and defect density. The approach is applied to the commonly used poly(styrene)-b-poly(methyl methacrylate) (PS-b-PMMA) and poly(styrene)-b-poly(2-vinylpyridine) (PS-b-P2VP) families of block copolymers, and it is found that the substrate resistivity, solvent environment, and anneal temperature all critically influence the self-assembly process. For selected systems, highly ordered patterns were achieved in less than 3 min. In addition, we establish the compatibility of the technique with directed assembly by graphoepitaxy.

Solar-energy-driven conversion of CO 2 into hydrocarbon fuels can simultaneously generate chemical fuels to meet energy demand and mitigate rising CO 2 levels. The utilization of the clean and renewable solar power resource is, on a longterm basis, an essential component of solutions to address growing global energy demand, which is projected to be 40 TW by 2050. [1] This is because the solar energy received on the earths surface in one hour exceeds current total global energy demand. From the perspective of climate change, expansion of the current fossil fuel-based energy infrastructure to meet the projected energy demand is predicted to add 2986-7402 Gt of CO 2 to the atmosphere by 2100, resulting in a mean rise in global temperature of 2.4-4.5 8C. [2] Since the discovery of the photoreduction of carbon dioxide to form organic compounds using semiconductors by Fujishima and co-workers in 1979, [3] a growing interest in the development of catalysts that are capable of solar-based capture and storage of CO 2 has evolved. [4] Titanium dioxide, which is a cost-efficient, non-toxic and abundant n-type semiconductor, has been widely considered in the solar-driven reduction of CO 2 . Owing to its large band-gap energy of 3-3.2 eV, TiO 2 without doping or post-synthesis treatments can absorb only the ultraviolet portion of the solar spectrum. To narrow the band-gap of TiO 2 and improve its photocatalytic performance, strategies such as compositional doping or deliberately introducing disorder in crystalline TiO 2 are being investigated. [5] Herein, we demonstrate an approach that is able to achieve high-rate sunlight-driven conversion of diluted CO 2 to light hydrocarbons in which an optimized combination of a Cu-Pt coating and modulated-diameter TiO 2 nanotubes are used as the photocatalyst. We demonstrate at least a fourfold improvement in CO 2 conversion rates over prior art [6] by using a catalyst consisting of coaxial Cu-Pt bimetallic shells supported on a periodically modulated double-walled TiO 2 nanotube (PMTiNT) array core. The photocatalytic reaction occurs at room temperature and generates CH 4 , C 2 H 4 , and C 2 H 6 as reaction products. Under AM 1.5 one-sun illumination, using 99.9 % CO 2 , we obtained a hydrocarbon production rate of 3.51 mL g À1 h À1 or 574 nmol cm À2 h À1 . A key novelty is the effectiveness of our photocatalyst for the photoreduction of unconcentrated CO 2 . When the Cu 0.33 -Pt 0.67 /PMTiNT heterogeneous catalyst was utilized for the photoreduction of diluted CO 2 (0.998 % in N 2 ) at 25 8C, we found an average hydrocarbon production rate of 3.7 mL g À1 h À1 or 610 nmol cm À2 h À1 . The periodic modulation of the diameters of the nanotube arrays increased the surface area and improved the utilization of light while the bimetallic coating increased catalyst activity and specificity. Our version of a highly active CO 2 reduction system does not require reactant gases with high purities and could potentially be used to photocatalytically capture CO 2 directly from air or from flue gas...

Objectives: To describe antimicrobial susceptibility among bacterial isolates associated with hospital infections collected from 266 centres in Asia/Pacific Rim (n 5 1947), North America (n 5 24 283), Latin America (n 5 1957) and Europe (n 5 8796).Methods: Isolates were collected from blood, respiratory tract, urine, skin, wound, body fluids and other defined sources between January 2004 and August 2006. Only one isolate per patient was accepted. In vitro MICs for the isolates were determined according to the CLSI (formerly NCCLS) guidelines.Results: Key organisms collected were Acinetobacter baumannii (n 5 2902), Enterobacter spp. (n 5 5731), Escherichia coli (n 5 6504), Klebsiella pneumoniae (n 5 4916), Pseudomonas aeruginosa (n 5 5128), Serratia marcescens (n 5 2313), Enterococcus faecalis (n 5 2701), Enterococcus faecium (n 5 1035) and Staphylococcus aureus (n 5 5753). Rates of methicillin resistance among S. aureus and of vancomycin resistance among enterococci were highest in North America (2016/3809, 52.9% and 571/2544, 22.4%, respectively) and lowest in Europe (337/1340, 25.1% and 36/916, 3.9%, respectively). Tigecycline was the only antimicrobial to maintain activity against all Gram-positive isolates (MIC 90 values of 0.25 mg/L). Overall, tigecycline and imipenem were the most active (>93% susceptibility in all regions) antimicrobials against the Gram-negative species, except for A. baumannii and P. aeruginosa. Piperacillin/tazobactam and amikacin were the most active against P. aeruginosa. Extended-spectrum b-lactamase producers among K. pneumoniae occurred most frequently in Latin America (124/282, 44.0%).Conclusions: Tigecycline is a novel broad-spectrum antimicrobial that is active against the common organisms associated with infections.

Copper sulfide semiconductors made from earth-abundant elements have an optical absorption edge at ca. 1.2 eV, nearly ideal for solar energy harvesting. We report the growth and formation mechanism of vertically oriented arrays of copper sulfide nanostructures formed by electrochemical anodization. Key parameters that affect the morphology and phase of the nanostructures are type and strength of electrolyte, anodization voltage and duration. Cu₂S and CuS nanostructures were obtained on both copper foil and copper-coated flexible Kapton substrates, and depending on the anodization parameters, consisted of vertically oriented arrays of nanowalls, nanoleafs or rods with branched nanodendrites. The anodization parameters also controlled the phase and stoichiometry of the nanostructures. p-type conduction for Cu₂S nanostructures and n-type conduction for CuS nanostructures were revealed by admittance spectroscopy and Mott Schottky analysis. We also observed a weak, but nevertheless promising and previously unnoticed, photocatalytic action in copper sulfide nanorod and platelet arrays for the sunlight-driven conversion of CO₂ into CH₄. Under irradiation by AM 1.5G simulated sunlight at room temperature, a CH₄ production rate as high as 38 μmol m(-2) h(-1) was obtained using the copper sulfide nanostructure arrays as stand-alone photocatalysts for CO₂ photoreduction.

Thin films cast from binary blends of structurally homologous polystyrene-block-poly(2-vinylpyridine) polymers were used to obtain horizontal arrays of linear nanostructures which were visualized by metallizing the poly(2-vinylpyridine) blocks with a tetrachloroplatinate salt. By varying the blend compositions of the homologous block copolymers, fine control over the periodicity of lines was realized from ∼25 to 55 nm using a set of just 4 block copolymers. For neat block copolymers whose equilibrium structures are not horizontal cylinders, blending enabled cylindrical structures to form. The ordering in various films was studied by measurements of defect density, and it was found that in many cases blended films produced patterns of lower defect density than patterns formed from single component block copolymers. Annealing of the polymer films was carried out using a solvothermal microwave annealing technique able to rapidly produce few-defect films. Here the technique is adapted to use a household microwave oven (cost < $100) to rapidly induce self-assembly in under 2 min, enabling broad accessibility.

Pathogens secret a plethora of effectors into the host cell to modulate plant immunity. Analysing the role of effectors in altering the function of their host target proteins will reveal critical components of the plant immune system. Here we show that Phytophthora infestans RXLR effector PITG20303, a virulent variant of AVRblb2 (PITG20300) that escapes recognition by the resistance protein Rpi-blb2, suppresses PAMP-triggered immunity (PTI) and promotes pathogen colonization by targeting and stabilizing a potato MAPK cascade protein, StMKK1. Both PITG20300 and PITG20303 target StMKK1, as confirmed by multiple in vivo and in vitro assays, and StMKK1 was shown to be a negative regulator of plant immunity, as determined by overexpression and gene silencing. StMKK1 is a negative regulator of plant PTI, and the kinase activities of StMKK1 are required for its suppression of PTI and effector interaction. PITG20303 depends partially on MKK1, PITG20300 does not depend on MKK1 for suppression of PTI-induced reactive oxygen species burst, while the full virulence activities of nuclear targeted PITG20303 and PITG20300 are dependent on MKK1. Our results show that PITG20303 and PITG20300 target and stabilize the plant MAPK cascade signalling protein StMKK1 to negatively regulate plant PTI response.

Block copolymers can be used to template large arrays of nanopatterns with periodicities equal to the characteristic spacing of the polymer. Here we demonstrate a technique capitalizing on the multilayered arrangement of cylindrical domains to effectively double the pattern density templated by a given polymer. By controlling the initial thickness of the film and the solvent annealing conditions, it was possible to reproducibly create density doubled lines by swelling the film with solvent until bilayers of horizontal cylinders were obtained. This process was also demonstrated to be compatible with graphoepitaxy.

Atherosclerosis is a chronic disease characterized by the accumulation of lipids and fibrous elements in the large arteries, which is the principal cause of coronary artery disease. Dysregulated exosomal microRNA (miRNA) levels in serum have been identified in patients with various diseases, including CAD. In the present study, nine candidate miRNAs were detected in the plasma exosome from 42 patients with coronary atherosclerosis, and a higher expression of miR-30e and miR-92a was identified in patients. Following bioinformatics analysis and confirmation through immunoblotting, it was demonstrated that ATP binding cassette (ABC)A1 is a direct target of miR-30e, and miR-92a. Furthermore, a negative correlation was identified between plasma miR-30e and ABCA1, or miR-30e and cholesterol. Thus, the results of the present study suggest that the miR-30e level in exosomes from serum may have the potential to be a novel diagnostic biomarker for coronary atherosclerosis.