100-fold improvement in carrier drift mobilities in alkanephosphonate-passivated monocrystalline TiO2 nanowire arrays.

Single crystal rutile titania nanowires grown by solvothermal synthesis are actively being researched for use as electron transporting scaffolds in perovskite solar cells, in low detection limit ultraviolet photodetectors, in photoelectrochemical water-splitting, and in chemiresistive and electrochemical sensing. The electron drift mobility (µ n ) in solution-grown TiO2 nanowires is very low due to a high density of deep traps, and reduces performance in optoelectronic devices. In this study, the effects of molecular passivation of the nanowire surface by octadecylphosphonic acid (ODPA), on carrier transport in TiO2 nanowire ensembles, were investigated using transient space charge limited current measurements. Infrared spectroscopy indicated the formation of a highly ordered phosphonate monolayer with a high likelihood of bidentate binding of ODPA to the rutile surface. We report the hole drift mobility (µ p ) for the first time in unpassivated solvothermal rutile nanowires to be 8.2 × 10-5 cm2 V-1 s-1 and the use of ODPA passivation resulted in µ p improving by nearly two orders of magnitude to 7.1 × 10-3 cm2 V-1 s-1. Likewise, ODPA passivation produced between a 2 and 3 order of magnitude improvement in µ n from ∼10-5-10-6 cm2 V-1 s-1 to ∼10-3 cm2 V-1 s-1. The bias dependence of the post-transit photocurrent decays in ODPA-passivated nanowires indicated that minority carriers were lost to trapping and/or monomolecular recombination for small values of bias (<5 V). Bimolecular recombination was indicated to be the dominant recombination mechanism at higher bias values.

Development of a high-performance liquid chromatographic-mass spectrometric assay for the specific and sensitive quantification of Ro 64-0802, an anti-influenza drug, and its pro-drug, oseltamivir, in human and animal plasma and urine.

Oseltamivir phosphate (Ro 64-0796/002) is a pro-drug of the anti-influenza neuraminidase inhibitor, Ro 64-0802, and as Tamiflu, has been developed for the treatment of both A and B strains of the disease. This paper describes an HPLC-MS-MS assay for both compounds in plasma and urine which fulfils all of the criteria for a good analytical method. It is sensitive with limits of quantification of 1 and 10 ng/ml for the pro-drug and active neuraminidase inhibitor, respectively. It is both accurate and precise with typical coefficients of variation from some 5,000 quality control samples of approximately +/-3 and +/-6%, respectively. Extensive stability studies have demonstrated the absence of significant problems associated with the decomposition of either compound, although ex vivo hydrolysis of Ro 64-0796 to Ro 64-0802 in rodent plasma has to be prevented by the use of the esterase inhibitor, dichlorvos.

Chromatographic and immunochemical approaches to the analysis of the HIV protease inhibitor saquinavir in plasma.

The development of the HIV protease inhibitor saquinavir (Ro 31-8959) required a range of analytical methods for its measurement in biological fluids. This paper describes the development of isocratic, reverse-phase HPLC/UV methods for the routine measurement of plasma levels of the drug together with a more sensitive radioimmunoassay. The performance of the two assays is compared with that of an HPLC/MS/MS method previously published and has been shown to be satisfactory, with coefficients of variation of calibration standards and quality control samples within the usual outside limits of +/- 15%. The HPLC/UV method can be routinely applied for concentrations down to 10-20 ng/ml and a lower limit of quantification of 1 ng/ml from 1 ml of human plasma is possible. The radioimmunoassay was developed for the specific measurement of saquinavir concentrations in human, HIV-positive plasma samples and has a lower limit of quantification of 0.5-1.0 ng/ml. Some preliminary findings suggested that it might not be specific in rat plasma and no attempts have been made to quantify any nonclinical samples with this technique. If still greater sensitivity is required, recourse can be made to the HPLC/MS/MS assay.

Challenging enterocutaneous fistula: a case presentation.

The management of an enterocutaneous fistula often presents a particular challenge for the WOC nurse. This generalization proved especially true in the following case of a patient with an Ileostomy and an enterocutaneous fistula who received salvage intravenous paclitaxel (Taxol) chemotherapy. The fistula underwent numerous changes after its development, necessitating multiple modifications in the pouching system. This article describes the management of this rapidly evolving fistula in a middle-aged woman with metastatic ovarian cancer.

Plasma biogenic amine levels in agoraphobia with panic attacks.

Eight patients with agoraphobia and panic attacks as defined by DSMIII and 11 controls were included in this study which measured the circulating biogenic amine levels. The method of assay used a high performance liquid chromatograph with electrochemical detection. Measurement of dopamine, noradrenaline and adrenaline showed no differences between the groups. Levels of serotonin (5-HT) were significantly lower in the agoraphobic group. The authors discuss the implication of this finding.

Haemoglobin Leiden in a South African negro. A case report.

A Black patient in whom an acute febrile illness was followed by a haemolytic crisis is presented. Investigation of the haemolytic anaemia showed the presence of an unstable haemoglobin which was found to be haemoglobin Leiden. Those members of the family who were available for investigation also had the unstable haemoglobin but showed no haemolysis. Radio-isotope studies on the patient confirmed haemolysis but showed that the spleen was not the main site of cell destruction.

The unstable Hb Genova (beta 28Leu replaced by Pro) in an East African Family. Family study and the effect of splenectomy.

A fifth family with the unstable Hb Genova is reported from Kenya, East Africa. This almost certainly represents an independent mutation. The beneficial effect of splenectomy has been carefully assessed in one member of the family.