Improved Optoelectronic Properties of Rapid Thermally Annealed Dilute Nitride GaInNAs Photodetectors

We investigate the optical and electrical characteristics of GaInNAs/GaAs long-wavelength photodiodes grown under varying conditions by molecular beam epitaxy and subjected to postgrowth rapid thermal annealing (RTA) at a series of temperatures. It is found that the device performance of the nonoptimally grown GaInNAs p-i-n structures, with nominal compositions of 10% In and 3.8% N, can be improved significantly by the RTA treatment to match that of optimally grown structures. The optimally annealed devices exhibit overall improvement in optical and electrical characteristics, including increased photoluminescence brightness, reduced density of deep-level traps, reduced series resistance resulting from the GaAs/GaInNAs heterointerface, lower dark current, and significantly lower background doping density, all of which can be attributed to the reduced structural disorder in the GaInNAs alloy.© 2012 TMS

Constructing Hierarchical Spheres from Large Ultrathin Anatase TiO2 Nanosheets with Nearly 100% Exposed (001) Facets for Fast Reversible Lithium Storage

Synthesis of nanocrystals with exposed high-energy facets is a well-known challenge in many fields of science and technology. The higher reactivity of these facets simultaneously makes them desirable catalysts for sluggish chemical reactions and leads to their small populations in an equilibrated crystal. Using anatase TiO2 as an example, we demonstrate a facile approach for creating high surface area, stable nanosheets comprised of nearly 100% exposed (001) facets. Our approach relies on spontaneous assembly of the nanosheets into three-dimensional, hierarchical spheres that stabilizes them from collapse. We show that the high surface density of exposed TiO2 (001) facets leads to fast lithium insertion/deinsertion processes in batteries that mimic features seen in high power electrochemical capacitors.X.W.L. and L.A.A. acknowledge support from Award KUS-C1-018-02 made by King Abdullah University of Science and Technology (KAUST). The authors are grateful to the reviewers and Prof. Hua Chun Zeng (National University of Singapore) for very valuable comments and to Nanyang Technological University for financial support through a startup grant (SUG)

The immunohistochemistry signature of mismatch repair (MMR) proteins in a multiethnic Asian cohort with endometrial carcinoma

Endometrial cancer is the most common gynecologic cancer in developed countries and is rising in incidence globally. Although the 5-year survival rates are >80%, factors beyond conventional pathologic features that predict clinical outcomes are still being elucidated. The aims of this study were to define the prevalence and associations of deficient mismatch repair (dMMR) protein expression (MLH1, MSH2, MSH6, PMS2) by immunohistochemistry in a multiethnic Southeast Asian cohort with endometrioid endometrial cancer. A total of 77 patients with adequate formalin-fixed paraffin-embedded specimens were identified. The sections were stained in 2 centers for 4 MMR proteins and examined by 2 independent specialist histopathologists. The mean age for the cohort was 58.6 yr, with 19.4% (15/77) of patients’ cancers showing loss of 2 MMR proteins. All 13 cancers with absent MLH1 showed PMS2 loss (13/15), whereas absent MSH2 correlated with MHS6 loss (2/15). There were no significant differences for dMMR cases in age, body mass index, histopathologic characteristics, and clinical outcomes. In dMMR cases, an overrepresentation of patients of Indian ethnic origin was observed compared with Chinese and Malays. These findings suggest that dMMR protein expression in a Southeast Asian endometrial cancer cohort does not correlate with disease outcomes

Fabrication of high energy-density hybrid supercapacitors using electrospun V 2O 5 nanofibers with a self-supported carbon nanotube network

10.1002/cplu.201200023ChemPlusChem777570-57