Photoresponse of n-TiO2 thin film and nanowire electrodes

Thin film and nanowire electrodes of n-type titanium oxide (n-TiO₂) were fabricated and their photoresponses towards water-splitting reaction were studied. A more than twofold increase in maximum photoconversion efficiency was observed when a single-layer thin film of n-TiO₂ was replaced by nanowires. Highest photoconversion efficiency was observed at an applied potential of 0.61 V vs. E_aoc where the electrode potential at open circuit, E_aoc was found to be −1.0 V SCE⁻¹ at illumination intensity of 40 mW cm⁻² in 5.0 M KOH solution. The maximum photoconversion efficiency was approximately of another twofold increase for water splitting at nanowire electrodes when methanol was used as a sacrifacial hole scavenger (depolarizing agent) in the electrolyte. Also, this maximum photoconversion efficiency was found at a lower applied potential of 0.41 V vs. E_aoc in presence of methanol. The band-gap energy of the n-TiO₂ films and nanowires annealed at 750°C was found to be 2.98 eV, which indicates their rutile structure.     

Relevance vector-machine-based solar cell model

This paper proposes an advanced machine learning method, relevance vector machines (RVMs), to model photovoltaic (PV) cells with a few measured data, over a range of expected operating conditions. RVMs are established on a Bayesian formulation which results in usage of less number of relevance vectors leading to much more sparse representation than the support vector machine. The RVM model can be used to predict short-circuit current and open-circuit voltage and thereby maximum power point for any unknown temperature and irradiation. Coordinate translation technique is used to plot the nonlinear I–V characteristics of PV cells. The proposed method matches the measured data more accurately than the pure neural network model and the neuro-fuzzy model.     

An open study of sertraline in acute and continuation treatment of depressed out-patients

The efficacy and tolerability of sertraline in 422 out-patients with major depression (DSM-III-R) was evaluated in an open multicentre 8-month study. Patients received sertraline 50 mg/day; if there was insufficient response at week 4, the dose was increased to 100 mg/day. After 8 weeks, 68.6% of patients had responded (> or = 50% reduction in Montgomery Asberg depression rating scale and clinical global impression scale scores of two or less (improvement of illness) and three or less (severity of illness); of patients receiving continuation treatment, 87.9% maintained at least a partial response at the final visit. The clinical response to the 50 mg/day dose was maintained throughout the acute treatment in 64% of patients. In all, 23% of the patients had mild or moderate drug-related gastrointestinal disturbances, which generally disappeared after 2 weeks. Only 8% of the patients withdrew because of side-effects. Just over half of the patients were taking other psychotropic drugs. Nevertheless the results of this open study are consistent with those of controlled studies in which sertraline was effective and well tolerated, in acute and continuation treatment for major depression, at 50 mg/day in most patients.     

Electrochemical treatment of reactive dye effluent using solar energy

The electrochemical degradation of a commonly used textile dye, Reactive Green HE4BD, employing solar energy has been investigated. The influence of parameters such as electrolyte concentration, current density, pH and initial dye concentration were studied. Under optimal conditions, 99% decoloration and a significant reduction in chemical oxygen demand were observed after 5 h treatment. Evaluation of the process showed that degradation of the dye followed pseudo first-order kinetics.     

Scaffold Hopping with Virtual Screening from IP3 to a Drug‐Like Partial Agonist of the Inositol Trisphosphate Receptor

Inositol 1,4,5‐trisphosphate (IP₃) is a universal signalling molecule that releases calcium from stores within cells by activating the IP₃ receptor. Although chemical tools that modulate the IP₃ receptor exist, none is ideal due to trade offs between potency, selectivity and cell permeability, and their chemical properties make them challenging starting points for optimisation. Therefore, to find new leads, we used virtual screening to scaffold hop from IP₃ by using the program ROCS to perform a 3D ligand‐based screen of the ZINC database of purchasable compounds. We then used the program FRED to dock the top‐ranking hits into the IP₃ binding pocket of the receptor. We tested the 12 highest‐scoring hits in a calcium‐release bioassay and identified SI‐9 as a partial agonist. SI‐9 competed with [³H]IP₃ binding, and reduced histamine‐induced calcium signalling in HeLa cells. SI‐9 has a novel 2D scaffold that represents a tractable lead for designing improved IP₃ receptor modulators.     

Novel Layered Hydroxyapatite/Tri‐Calcium Phosphate–Zirconia Scaffold Composite with High Bending Strength for Load‐Bearing Bone Implant Application

The integration of biological and mechanical requirements remains a challenge in developing porous hydroxyapatite (HA) and tri‐calcium phosphate (TCP) scaffolds for load‐bearing bone implant application. With the newly developed slip‐deposition and coating‐substrate co‐sintering technique, a strong layered HA/TCP‐zirconia scaffold composite structure was successfully fabricated. The bending strength (321 MPa) of this composite can match upper strength limit of the natural compact bone. The HA‐based scaffold coating has multiple scale porous structures with pore size ranging 1–10 and 20–50 μm. The zirconia‐based substrate is also porous with submicropores. Focus ion beam micrographs show most of the micropores in the coating are interconnected. Microindentation and primarily adhesive strength tests demonstrate that the scaffold coating strongly bonds with the zirconia based substrate. In vitro cell culture study indicates that the coatings have no cytotoxicity. It is evident that the strong layered HA–zirconia scaffold composite offers new implant options for bone repairs requiring immediate load bearing capacity.     

Chitosan-Based Nanocomposite Scaffolds for Tissue Engineering Applications

This article reports the fabrication of three-dimensional porous chitosan and hydroxyapatite (HA)/chitosan composite scaffolds by the thermally induced phase separation (TIPS) technique, for bone tissue engineering. Different amounts of HA nanoparticles (10%, 20%, and 30% g/g) were added to the chitosan solution to produce HA/chitosan composite scaffolds of varying compositions. The morphology and pore structure of the scaffolds vis-à-vis composition were characterized using scanning electron microscopy (SEM) and an energy dispersive X-ray (EDX). Both pure chitosan and HA/chitosan composite scaffolds were highly porous and had interconnected pores. The pore sizes ranged from several micrometers to a few hundred micrometers. The HA nanoparticles were well dispersed and physically coexisted with chitosan in the composite scaffolds. However, some agglomeration of HA nanoparticles was observed on the surface of pore walls when a relatively large amount of HA was used. The composite 3D scaffolds are very promising for use in bone tissue engineering application.     

Nitrogen‐Induced Surface Area and Conductivity Modulation of Carbon Nanohorn and Its Function as an Efficient Metal‐Free Oxygen Reduction Electrocatalyst for Anion‐Exchange Membrane Fuel Cells

Nitrogen‐doped carbon morphologies have been proven to be better alternatives to Pt in polymer‐electrolyte membrane (PEM) fuel cells. However, efficient modulation of the active sites by the simultaneous escalation of the porosity and nitrogen doping, without affecting the intrinsic electrical conductivity, still remains to be solved. Here, a simple strategy is reported to solve this issue by treating single‐walled carbon nanohorn (SWCNH) with urea at 800 °C. The resulting nitrogen‐doped carbon nanohorn shows a high surface area of 1836 m² g^?1 along with an increased electron conductivity, which are the pre‐requisites of an electrocatalyst. The nitrogen‐doped nanohorn annealed at 800 °C (N‐800) also shows a high oxygen reduction activity (ORR). Because of the high weight percentage of pyridinic nitrogen coordination in N‐800, the present catalyst shows a clear 4‐electron reduction pathway at only 50 mV overpotential and 16 mV negative shift in the half‐wave potential for ORR compared to Pt/C along with a high fuel selectivity and electrochemical stability. More importantly, a membrane electrode assembly (MEA) based on N‐800 provides a maximum power density of 30 mW cm^?2 under anion‐exchange membrane fuel cell (AEMFC) testing conditions. Thus, with its remarkable set of physical and electrochemical properties, this material has the potential to perform as an efficient Pt‐free electrode for AEMFCs.     

Cultural roadmap: Developing cultural learning strategies during internship.

Cultural training can be a difficult topic to address during the internship year and can be defined or approached in many different ways. This article describes a program designed to provide cultural training focused on increasing cultural awareness for psychology interns. The training program outlined is based in part on anthropological research methods and teaches interns a method for learning about different cultures. Interns focus on one cultural group, and go through a flexible sequence of several steps from gathering general information, meeting with community representatives, meeting specific groups of community members, to finally developing a project using the information learned to serve the group studied. An overview of the program is provided, with a recent project example to highlight the process. Reactions from interns have generally been positive. Examples are discussed of how the project has evolved to reflect intern and staff experiences. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Allowed and forbidden transition parameters for Fe XXII

Radiative transitions for photo-excitations and de-excitations in Fe XXII are studied in the relativistic Breit-Pauli approximation. A comprehensive set of fine structure energy levels, oscillator strengths (f), line strengths (S), and radiative decay rates (A) for electric dipole (E1), same spin multiplicity and intercombination, fine structure transitions is presented. These are obtained from the first calculations in the close coupling approximation using the Breit-Pauli R-matrix method for this ion, all existing theoretical results having been obtained from various other atomic structure calculations. The present work obtains a set of 771 fine structure energy levels with n ? 10, l ? 9, and 1/2 ? J ? 17/2, only 52 of which have been observed. The f, S, and A values are reported for 70,372 allowed E1 transitions, exceeding by far those published previously. The calculated fine structure levels have been identified spectroscopically using a procedure based on quantum defect analysis. The energies agree with the available observed energies to within less than one to a few percent. The A values for E1 transitions are in good agreement with other existing values for most transitions. Using the atomic structure code SUPERSTRUCTURE (SS), S and A values are also presented for 38,215 forbidden transitions of the types electric quadrupole (E2), electric octupole (E3), magnetic dipole (M1), and magnetic quadrupole (M2) among 274 fine structure levels formed from 25 configurations with orbitals ranging from 1s to 4f. Some of these levels lie above the ionization limit and hence can form autoionizing lines. Such lines for 1s-2p K_α transitions have been observed in experiments. The energies from the SS calculations agree with observed energies within a few percent. The A values for E2 and M1 transitions agree very well with the available values. The atomic parameters for both allowed and forbidden transitions should be applicable for diagnostics as well as complete spectral modeling in the X-ray, ultraviolet, and optical regimes of astrophysical and laboratory plasmas.