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Selected AbstractsUV emission on a Si substrate: Optical and structural properties of ,-CuCl on Si grown using liquid phase epitaxy techniquesPHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 5 2009A. Cowley Abstract Considerable research is being carried out in the area of wide band gap semiconductor materials for light emission in the 300,400 nm spectral range. Current materials being used for such devices are typically based on II,VI and III-nitride compounds and variants thereof. However, one of the major obstacles to the successful fabrication of III-N devices is lattice mismatch-induced high dislocation densities for epitaxially grown layers on non-native substrates. ,-CuCl is a direct bandgap material and an ionic wide bandgap I,VII semiconductor with a room temperature free exciton binding energy of ,190 meV (compared to ,25 meV and ,60 meV for GaN and ZnO, respectively) and has a band gap of 3.4 eV (, , 366 nm). The lattice constant of ,-CuCl (0.541 nm) is closely matched to that of Si (0.543 nm). This could, in principle, lead to the development of optoelectronic systems based on CuCl grown on Si. Research towards this end has successfully yielded polycrystalline ,-CuCl on Si(100) and Si(111) using vacuum-based deposition techniques [1]. We report on developments towards achieving single crystal growth of CuCl from solution via Liquid Phase Epitaxy (LPE) based techniques. Work is being carried out using alkali halide flux compounds to depress the liquidus temperature of the CuCl below its solid phase wurtzite-zincblende transition temperature (407 °C [2]) for solution based epitaxy on Si substrates. Initial results show that the resulting KCl flux-driven deposition of CuCl onto the Si substrate has yielded superior photoluminescence (PL) and X-ray excited optical luminescence (XEOL) behavior relative to comparitively observed spectra for GaN or polycrystalline CuCl. This enhancement is believed to be caused by an interaction between the KCl and CuCl material subsequent to the deposition process, perhaps involving a reduction in Cl vacancy distributions in CuCl. This paper presents a detailed discussion of a CuCl LPE growth system as well as the characterization of deposited materials using X-ray diffraction (XRD), room temperature and low temperature PL, and XEOL. (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Thermal Conductivity of the Rare-Earth Strontium AluminatesJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 5 2010Chunlei Wan The thermal conductivity of a series of complex aluminates, RE2SrAl2O7, with different rare-earth (RE) ions, has been measured up to 1000°C. There is a strong dependence on the atomic number of the RE ion, ranging from an approximately 1/T dependence for the lanthanum strontium aluminate to an almost temperature-independent behavior of the dysprosium strontium aluminate. The latter conductivity is comparable with that of yttria-stabilized zirconia, the current material of choice for thermal barrier coatings. The temperature dependence of the thermal conductivities of all the aluminates studied can be fit to a standard phonon,phonon scattering model, modified to account for a minimum phonon mean free path, in which the difference in behavior is attributed to increased phonon,phonon scattering with the atomic mass of the RE ion. Although a satisfactory parametric fit is obtained, the model does not take into account either the detailed layer structure of the aluminates, consisting of alternating rock-salt and perovskite layers in a natural superlattice structure, or the site preferences of the RE ion. This suggests that further model development is warranted. [source] Boronic Acid Functionalized Core,Satellite Composite Nanoparticles for Advanced Enrichment of Glycopeptides and GlycoproteinsCHEMISTRY - A EUROPEAN JOURNAL, Issue 39 2009Lijuan Zhang Abstract A core,satellite-structured composite material has been successfully synthesized for capturing glycosylated peptides or proteins. This novel hybrid material is composed of a silica-coated ferrite "core" and numerous "satellites" of gold nanoparticles with lots of "anchors". The anchor, 3-aminophenylboronic acid, designed for capturing target molecules, is highly specific toward glycosylated species. The long organic chains bridging the gold surface and the anchors could reduce the steric hindrance among the bound molecules and suppress nonspecific bindings. Due to the excellent structure of the current material, the trap-and-release enrichment of glycosylated samples is quite simple, specific, and effective. Indeed, the composite nanoparticles could be used for enriching glycosylated peptides and proteins with very low concentrations, and the enriched samples can be easily separated from bulk solution by a magnet. By using this strategy, the recovery of glycopeptides and glycoproteins after enrichment were found to be 85.9 and 71.6,% separately, whereas the adsorption capacity of the composite nanoparticles was proven to be more than 79,mg of glycoproteins per gram of the material. Moreover, the new composite nanoparticles were applied to enrich glycosylated proteins from human colorectal cancer tissues for identification of N-glycosylation sites. In all, 194 unique glycosylation sites mapped to 155 different glycoproteins have been identified, of which 165 sites (85.1,%) were newly identified. [source] Sudden infant death syndrome during low incidence in Sweden 1997,2005ACTA PAEDIATRICA, Issue 1 2010P Möllborg Abstract Background:, Following the change from prone to supine in preferred sleeping position, the incidence of Sudden Infant Death Syndrome (SIDS) in Sweden fell from 1.1 per 1000 live births in 1992 to 0.41 in 1995. After a further small decline, we have been experiencing a plateau at around 0.25 since 2000. Aim:, To identify the changes that have occurred in the epidemiology of SIDS since the end of the Nordic Epidemiological SIDS Study in 1995. Methods:, Data from the Medical Birth Register of Sweden, covering the years 1995,2005, were used. Sleeping position is not included in the register. Results:, The incidence of SIDS has remained low in Sweden. Independent risk factors were smoking during early pregnancy, parents not living together, low maternal age, high parity and short gestational age. The odds ratio for smoking has continued to increase and the median age of death has continued to decrease since the previous study. We found no signs of seasonality in the current material. Conclusions:, Age at death continued to decrease. The high incidence during weekends persisted. Seasonality was not significant. There was no evidence of a changing effect from risk factors in the studied period. [source] Thermally associating polypeptides designed for drug delivery produced by genetically engineered cellsJOURNAL OF PHARMACEUTICAL SCIENCES, Issue 3 2007David S. Hart Abstract Thermally associating polymers, including gelatin, cellulose ethers (e.g., Methocels® and poloxamers (e.g., Pluronics®) have a long history of use in pharmacy. Over the past 20 years, significant advances in genetic engineering and the understanding of protein secondary and tertiary structures have been made. This has led to the development of a variety of polypeptides that do not occur naturally but can be expressed in recombinant cells and have useful properties that lend themselves to novel applications where current materials cannot perform. The most intensively studied motifs are derived from the consensus repeats of elastin and silk, as well as coiled-coil helices. Many of these designed polypeptides or ,artificial proteins' are thermally associating materials. This property can be exploited to develop solid dosage forms, injectable drug delivery systems, micro- or nanoparticle drug carriers, triggered or targeted release systems, or as a means of simplifying the purification process and thus reducing costs of production of these materials. This review focuses on the development and characterization of this novel class of biomaterials and examines their potential for pharmaceutical applications. © 2006 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci [source] | ||||||||||