Synthesis, characterization and photocatalytic activity of Al₂O₃-TiO₂ based composites

The synthesis, characterization and photocatalytic performance of non-traditional Al₂O₃-TiO₂-based photocatalysts is reported. Al₂O₃-TiO₂ support was loaded with various fractions of CuO and ZrO₂. A sound agreement was observed between the bandgaps of synthesized powders measured by UV-Visible diffuse reflectance spectroscopy (DRS) in the solid phase and UV-Visible spectroscopy in the aqueous medium. X-ray diffraction (XRD) analysis revealed the composite nature of the catalysts with the retention of individual identity of each component. The average crystallite size of the individual component was found to be in the range of 20 to 40 nm. Scanning electron microscopy (SEM) analysis authenticated the presence of CuO and ZrO₂ at the surface of Al₂O₃-TiO₂ support, while Rutherford Back Scattering Spectroscopy (RBS) confirmed the quantity of the modifiers as per theoretical calculations. The composites showed an enhanced photocatalytic activity in sunlight compared to Al₂O₃-TiO₂ for the degradation of dyes. Efforts were made to elucidate the enhanced sunlight response of the synthesized composite catalysts compared to Al₂O₃-TiO₂. As monitored by ion chromatography (IC), the synthesized photocatalysts completely mineralized the dyes leaving behind inorganic ions in solution. The kinetics of photocatalytic degradation of dyes was evaluated for optimum correlation with the existing models. The stability of the photocatalysts against the photo-corrosion was monitored by analyzing the samples for respective metals in solution after sunlight exposure. Supplemental materials are available for this article. Go to the publisher's online edition of the Journal of Environmental Science and Health, Part A, to view the supplemental file.

Defect controlled water splitting characteristics of gold nanoparticle functionalized ZnO nanowire films

An ITO/FTO free AuNP functionalized ZnO NW photoanode in a dual role such as photo active centers for catalytic activity and an efficient transport medium for photo-generated charge carriers.

Ce3+ impregnated ZnO: a highly efficient photocatalyst for sunlight mediated mineralization

The surface of pre-synthesized hexagonal ZnO was tailored by Ce³⁺ states.

Validation of a novel duplex ultrasound objective structured assessment of technical skills (DUOSATS) for arterial stenosis detection

INTRODUCTION

Duplex ultrasound facilitates bedside diagnosis and hence timely patient care. Its uptake has been hampered by training and accreditation issues. We have developed an assessment tool for Duplex arterial stenosis measurement for both simulator and patient based training.

METHODS

A novel assessment tool: duplex ultrasound assessment of technical skills was developed. A modified duplex ultrasound assessment of technical skills was used for simulator training. Novice, intermediate experience and expert users of duplex ultrasound were invited to participate. Participants viewed an instructional video and were allowed ample time to familiarize with the equipment. Participants' attempts were recorded and independently assessed by four experts using the modified duplex ultrasound assessment of technical skills. 'Global' assessment was also done on a four point Likert scale. Content, construct and concurrent validity as well as reliability were evaluated.

RESULTS

Content and construct validity as well as reliability were demonstrated. The simulator had good satisfaction rating from participants: median 4; range 3-5. Receiver operator characteristic analysis has established a cut point of 22/ 34 and 25/ 40 were most appropriate for simulator and patient based assessment respectively. We have validated a novel assessment tool for duplex arterial stenosis detection. Further work is underway to establish transference validity of simulator training to improved skill in scanning patients.

CONCLUSIONS

We have developed and validated duplex ultrasound assessment of technical skills for simulator training.

Alar base resection - Medial flap technique

The primary goal of alar base resection is the narrowing of nasal base while preserving or recreating normal contour. The standard wedge resection, as proposed by Weir, does narrow the base but too open at the expense of normal appearing nostrils. 25 patients were taken up for corrective septo-rhinoplasty of which 5 patients needed alar base resection. The medial flap technique as proposed by Jack Sheen was adopted and normal appearing nasal base achieved in all cases.

Polyelectrolyte coated polymeric nanoparticles for controlled release of docetaxel

Polyelectrolyte coatings are effective means of minimizing the rate of release of small molecules from a nanoparticle system. The current investigation aim at developing biodegradable drug delivery carriers composed of three types of polymers viz poly(lactide-co-glycolic) acid [PLGA], poly(lactide-co-glycolic) acid-polyethylene imine [PLGA-PEI] and poly lactic acid [PLA]. The PLGA and PLGA-PEI nanoparticles were in the size range approximately 150 nm while PLA nanoparticles were approximately 80 nm in size respectively. The nanoparticles were found to encapsulate 66%, 62% and 65% of the hydrophobic drug, Docetaxel (DOCE) respectively. "Layer by Layer (LbL)" self assembly technique was then performed to coat these particles with polyelectrolyte thin films (PEs). DLS studies showed hydrodynamic diameter of 330 nm, 350 nm and 310 nm for the coated PLGA, PLGA-PEI and PLA nanoparticles respectively, while SEM and TEM studies demonstrated that after coating the particle sizes were approximately 200 nm for all the three nanoparticles. In vitro drug release studies demonstrated that at the end of 24 hours, about 83%, 90% and 88% of drug was released from uncoated PLA, PLGA-PEI and PLGA nanoparticles respectively. Using LbL coating, the same amount of the drug was found to be released in a sustained way for up to 7 days for PLGA and up to 6 days for PLGA-PEI and PLA nanoparticles. In vitro cytocompatibility studies were carried out with each system and the cell viability at end of 48 hours was found to be in the range of 70% to 100%. Current approach of sustained drug delivery can help in improving the therapeutic efficiency of the breast cancer drug, DOCE.

Intermedin (adrenomedullin2) stabilizes the endothelial barrier and antagonizes thrombin-induced barrier failure in endothelial cell monolayers

BACKGROUND AND PURPOSE

Intermedin is a member of the calcitonin gene-related-peptide (CGRP) family expressed in endothelial cells and acts via calcitonin receptor-like receptors (CLRs). Here we have analysed the receptors for intermedin and its effect on the endothelial barrier in monolayers of human umbilical vein endothelial cells (HUVECs).

EXPERIMENTAL APPROACH

We analysed the effect of intermedin on albumin permeability, contractile machinery, actin cytoskeleton and VE-cadherin in cultured HUVECs.

KEY RESULTS

Intermedin concentration-dependently reduced basal endothelial permeability to albumin and antagonized thrombin-induced hyperpermeability. Intermedin was less potent (EC(50) 1.29 ± 0.12 nM) than adrenomedullin (EC(50) 0.24 ± 0.07 nM) in reducing endothelial permeability. These intermedin effects were inhibited by AM(22-52) and higher concentrations of αCGRP(8-37), with pA(2) values of αCGRP(8-37) of 6.4 for both intermedin and adrenomedullin. PCR data showed that HUVEC expressed only the CLR/RAMP2 receptor complex. Intermedin activated cAMP/PKA and cAMP/Epac signalling pathways. Intermedin's effect on permeability was blocked by inhibition of PKA but not of eNOS. Intermedin antagonized thrombin-induced contractile activation, RhoA activation and stress fibre formation. It also induced Rac1 activation, enhanced cell-cell adhesion and antagonized thrombin-induced loss of cell-cell adhesion. Treatment with a specific inhibitor of Rac1 prevented intermedin-mediated barrier stabilization.

CONCLUSION AND IMPLICATIONS

Intermedin stabilized endothelial barriers in HUVEC monolayers via CLR/RAMP2 receptors. These effects were mediated via cAMP-mediated inactivation of contractility and strengthening of cell-cell adhesion. These findings identify intermedin as a barrier stabilizing agent and suggest intermedin as a potential treatment for vascular leakage in inflammatory conditions.

2-[(2-Methoxybenzylidene)amino]phenol

In the title compound, C₁₄H₁₃NO₂, the azomethine double bond adopts an E conformation and the benzene rings form a dihedral angle of 77.70 (7)°. In the crystal, mol­ecules are linked by O—H⋯N and C—H⋯O hydrogen bonds and arranged in a zigzag fashion, forming infinite chains parallel to the c axis, resulting in a graph-set R₂²(9) motif.

Effect of Fe doping concentration on optical and magnetic properties of ZnO nanorods

Herein, a facile low temperature, aqueous solution-based chemical method has been demonstrated for large-scale fabrication of Fe doped ZnO nanorods (ZnO:Fe) with a series percentage of Fe dopant. Interestingly, the SEM results reveal a uniform well dispersed synthesis of ZnO:Fe nanorods throughout the substrate. The x-ray diffraction result suggests that Fe substitutes Zn in the ZnO matrix and rules out the formation of any secondary phase. Selected area electron diffraction investigation verifies the single crystal, hexagonal wurtzite structure of the ZnO:Fe nanorods. Energy dispersive spectroscopy data confirm Fe doping of the ZnO nanorods with a concentration ranging from 0.9 to 2.2 at.%. The photoluminescence spectrum reveals a continuous suppression of defect related broad-band emission (I(D)/I(UV) = 1-0.11) by increasing the concentration of the dopant ion, which produces the quenching of surface defects present in the nanostructures. An enhancement in ferromagnetism (M = 0.15 × 10⁻²-0.24 × 10⁻¹ emu g⁻¹ at 2000 Oe) is found in doped ZnO nanorods.

{2-[(3-Bromo-benzyl-idene)amino]-5-chloro-phen-yl}(phen-yl)methanone

In the title compound, C₂₀H₁₃BrClNO, the azomethine double bond [C=N = 1.246 (4) Å] adopts an E conformation. The bromo- and chlorophenyl rings are inclined to one another by 13.70 (11)°, and form dihedral angles of 76.68 (10) and 74.24 (7)°, respectively, with the phenyl ring. In the crystal, mol­ecules are linked by C—H⋯O hydrogen bonds to form double stranded chains propagating along the b-axis direction.

17-(Pyrimidin-2-yl)-8,16-dioxa-17-aza-tetra-cyclo-[7.7.1.0.0]hepta-deca-2,4,6,10,12,14-hexa-ene

In the title compound, C(18)H(13)N(3)O(2), the benzene rings form a dihedral angle of 78.49 (9)°. The dihedral angles between the benzene rings and the pyrimidine ring are 76.53 (10) and 27.73 (11)°. The two cis-fused six-membered heterocyclic rings adopt half-chair confirmations. In the crystal, mol-ecules are linked by C-H⋯O hydrogen bonds, forming chains parallel to the b axis.