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Unique electronic properties of semiconductor heterostructured nanowires make them useful for future nano-electronic devices. Here, we present a study of the band bending effect at the heterointerface of GaAs/InAs core/shell nanowires by means of synchrotron based X-ray photoelectron spectroscopy. Different Ga, In, and As core-levels of the nanowire constituents have been monitored prior to and after cleaning from native oxides. The cleaning process mainly affected the Asoxides and was accompanied by an energy shift of the core-level spectra towards lower binding energy, suggesting that the As-oxides turn the nanowire surfaces to n-type. After cleaning, both As and Ga core-levels revealed an energy shift of about -0.3 eV for core/shell compared to core reference nanowires. With respect to depth dependence and in agreement with calculated strain distribution and electron quantum confinement, the observed energy shift is interpreted by band bending of core-levels at the heterointerface between the GaAs nanowire core and the InAs shell. [ABSTRACT FROM AUTHOR]

Scanning electron microscopic and X-ray diffraction studies of Cu(II) oxide films, deposited by oxidizing gas source and pulsed laser ablation on MgO(100) substrates, revealed that the Cu films are pure and exhibit good orientation. The growth rate of the films ranged from 0.025 to 0.035 Angstroms per laser pulse at the substrate temperature range between 50 and 600 degrees Celsius. Time-of-flight mass spectroscopy of the films revealed that the relative placement of the pulsed valve and copper target, and the relative timing of the gas and laser pulses determine film purity.

Isophorone is a technically important compound used as a high-boiling-point solvent for coatings, adhesives, etc., and it is used as a starting material for various valuable compounds, including isophorone diisocyanate, a precursor for polyurethanes. For over 80 years, isophorone has been synthesized via base-catalyzed self-condensation of acetone. This reaction has a complex reaction mechanism with numerous possible reaction steps including the formation of isophorone, triacetone dialcohol, and ketonic resins. This review provides an overview of the different production processes of isophorone in liquid- and vapor-phase and reviews the literature-reported selectivity toward isophorone achieved using different reaction parameters and catalysts.

Cross-sectional scanning tunneling microscopy results on GaSb quantum wells and dots in GaAs are found to exhibit a narrow, sharply defined contrast of the nanostructure at negative sample bias, but a smoothly broadened contrast at positive sample bias. This contrast is related to the specific type-II band alignment of GaSb/GaAs heterostructures in combination with tip-induced band bending. The corresponding model is quantitatively verified by numerical simulations of band bending and tunnel current profiles combined with calculations of cleavage-induced strain relaxation. [ABSTRACT FROM AUTHOR]

Using plan-view and cross-sectional scanning tunneling microscopy, the shape and composition of InAs/GaAs quantum dots are investigated before and after capping by GaAs. During capping, the original pyramidally shaped quantum dots become truncated, resulting in a flat (001) top facet and steeper side facets. The InAs quantum dots are found to be intermixed at their top with GaAs due to material rearrangement. Since the bottom interface of quantum dots and wetting layer is always sharp, this intermixing occurs during capping and not during quantum dot growth. Considering strain energies, a model for the capping is presented. [ABSTRACT FROM AUTHOR]

Investigates the interaction and energy transfer of a laser ablation plasma of Ti with a pulsed N2 supersonic expansion using time-of-flight quadrupole mass spectroscopy and Langmuir probe techniques. Coupling of the nascent plasma with the gas pulse; Timing between the gas pulse and ablation plume; Ion signal quenching by the N2 number density.

Phytochromes are bistable red/far-red light-responsive photoreceptor proteins found in plants, fungi, and bacteria. Light-activation of the prototypical phytochrome Cph1 from the cyanobacterium Synechocystis sp. PCC 6803 allows photoisomerization of the bilin chromophore in the photosensory module and a subsequent series of intermediate states leading from the red absorbing Pr to the far-red-absorbing Pfr state. We show here via osmotic and hydrostatic pressure-based measurements that hydration of the photoreceptor modulates the photoconversion kinetics in a controlled manner. While small osmolytes like sucrose accelerate Pfr formation, large polymer osmolytes like PEG 4000 delay the formation of Pfr. Thus, we hypothesize that an influx of mobile water into the photosensory domain is necessary for proceeding to the Pfr state. We suggest that protein hydration changes are a molecular event that occurs during photoconversion to Pfr, in addition to light activation, ultrafast electric field changes, photoisomerization, proton release and uptake, and the major conformational change leading to signal transmission, or simultaneously with one of these events. Moreover, we discuss this finding in light of the use of Cph1-PGP as a hydration sensor, e.g., for the characterization of novel hydrogel biomaterials.

Abstract Objective Insurers frequently commission medical experts to estimate the degree of the remaining work capacity (RWC) in claimants for disability benefits. The social functioning scale Mini-ICF-APP allows for a rating of activity and participation limitations in thirteen capacity domains, considered as particularly relevant for work ability. The current study sought to evaluate the role of the Mini-ICF-APP ratings in psychiatric work disability evaluations, by examining how the capacity limitation ratings varied with the claimants’ primary psychiatric diagnoses and how the ratings were related to RWC estimates. Methods Medical experts estimated the RWC of 946 claimants with mental disorders and rated their activity and participation limitations using the Mini-ICF-APP, with higher ratings reflecting more severe limitations. The ratings were compared between claimants with different psychiatric diagnoses by analyses of variance. The mean Mini-ICF-APP rating across all capacity domains as well as all capacity-specific ratings were entered in simple or multiple regression models to predict the RWC in an alternative job. Results The Mini-ICF-APP capacity limitation ratings in all domains but mobility were higher for claimants with personality and behavior disorders as compared to those with mood disorders or with neurotic, stress-related and somatoform disorders. The largest differences were observed in social capacities (e.g. group integration: F 2, 847 = 78.300, P 16.393, all Ps