Operating theatre photography for orthopaedics and aesthetic surgery.

The aim of this paper is to examine the author's personal experience and practice in operating theatre photography. The ways of working are personal to the author but hopefully will help others in undertaking this type of work

LC–MS/MS determination of carbamathione in microdialysis samples from rat brain and plasma

A selective liquid chromatography–tandem mass spectrometric (LC–MS/MS) method was developed for the determination of S-(N, N-diethylcarbamoyl) glutathione (carbamathione) in microdialysis samples from rat brain and plasma. S-(N, N-Diethylcarbamoyl) glutathione (carbamathione) is a metabolite of disulfiram. This metabolite may be responsible for disulfiram’s effectiveness in the treatment of cocaine dependence. An analytical method using liquid chromatography–tandem mass spectrometric (LC–MS/MS) was developed to determine carbamathione in vivo using microdialysis sampling from rat brain and plasma. Chromatographic separations were carried out on an Alltech Altima C-18 (50 mm long × 2.1 mm i.d., 3 μm particles) analytical column at a flow rate of 0.3 ml/min. Solvent A consisted of 10 mM ammonium formate, methanol, and formic acid (99:1:0.06, v/v/v). Solvent B consisted of methanol, 10 mM ammonium formate and formic acid (99:1:0.06, v/v/v). A 20 min linear gradient from 95% aqueous to 95% organic was used. Tandem mass spectra were acquired on a Micromass Quattro Ultima “triple” quadrupole mass spectrometer equipped with an ESI interface. Quantitative mass spectrometric analysis was conducted in positive ion mode selected reaction monitoring (SRM) mode looking at the transition of m/z 407–100 and 175 for carbamathione and m/z 392–263 for the internal standard S-hexyl glutathione. The simultaneous collection of microdialysate from blood and brain was used to monitor carbamathione concentrations centrally and peripherally. Good linearity was obtained over a concentration range of 0.25–10,000 nM. The lowest limit of quantification (LLOQ) was determined to be 1 nM and the lowest limit of detection (LLOD) was calculated to be 0.25 nM. Intra- and inter-day accuracy and precision were determined and for all the samples evaluated, the variability was less that 10% (R.S.D.)

NASA Ares I Launch Vehicle Upper Stage Reaction Control System (ReCS) Cold Flow Development Test Overview

NASA s Ares I launch vehicle, consisting of a five segment solid rocket booster first stage and a liquid bi-propellant J2-X engine Upper Stage, is the vehicle that s been chosen to launch the Orion Crew Module, which will return humans to the Moon, Mars, and beyond. After First Stage booster separation, the Reaction Control System (ReCS), a monopropellant hydrazine system, will provide the Upper Stage element with three degrees of freedom control as needed. This paper provides an overview of the system level development testing that has taken place on the Ares I launch vehicle Upper Stage ReCS. The ReCS System Development Test Article (SDTA) was built as a flight representative water flow test article whose primary test objective was to obtain fluid system performance data to evaluate the integrate system performance characteristics and verify analytical models. Water is the industry standard for cold flow testing of hydrazine systems, because the densities are very close and the speeds of sound are well characterized. The completion of this development level test program was considered necessary to support the ReCS Critical Design Review. This paper will address the design approach taken in building the test article, the objectives of the test program, types of testing completed, general results, the ability of the program to meet the test objectives, and lessons learne

S-(N, N-diethylcarbamoyl)glutathione (carbamathione), a disulfiram metabolite and its effect on nucleus accumbens and prefrontal cortex dopamine, GABA, and glutamate: A microdialysis study

Disulfiram (DSF), used for the treatment of alcohol use disorders (AUDs) for over six decades, most recently has shown promise for treating cocaine dependence. Although DSF’s mechanism of action in alcohol abuse is due to the inhibition of liver mitochondrial aldehyde dehydrogenase (ALDH2), its mechanism of action in the treatment of cocaine dependence is unknown. DSF is a pro-drug, forming a number of metabolites each with discrete pharmacological actions. One metabolite formed during DSF bioactivation is S-(N, N-diethylcarbamoyl) glutathione (carbamathione) (carb). We previously showed that carb affects glutamate binding. In the present studies, we employed microdialysis techniques to investigate the effect of carb administration on dopamine (DA), GABA, and glutamate (Glu) in the nucleus accumbens (NAc) and medial prefrontal cortex (mPFC), two brain regions implicated in substance abuse dependence. The effect of DSF on DA, GABA, and Glu in the NAc also was determined. Both studies were carried out in male rats. Carb (20, 50, 200 mg/kg i v) in a dose-dependent manner increased DA, decreased GABA, and had a biphasic effect on Glu, first increasing and then decreasing Glu in both the NAc and mPFC. These changes all occurred concurrently. After carb administration, NAc and mPFC carb, as well as carb in plasma, were rapidly eliminated with a half-life for each approximately 4 min, while the changes in DA, GABA, and GLu in the NAc and mPFC persisted for approximately two hours. The maximal increase in carb (Cmax) in the NAc and mPFC after carb administration was dose-dependent, as was the area under the curve (AUC). DSF (200 mg/kg i p) also increased DA, decreased GABA, and had a biphasic effect on Glu in the NAc similar to that observed in the NAc after carb administration. When the cytochrome P450 inhibitor N-benzylimidazole (NBI) (20 mg/kg i p) was administered before DSF dosing, no carb could be detected in the NAc and plasma and also no changes in NAc DA, GABA, and GLu occurred. Changes in these neurotransmitters occurred only if carb was formed from DSF. When NBI was administered prior to dosing with carb, the increase in DA, decrease in GABA, and biphasic effect on GLu was similar to that seen after dosing with carb only. The i p or i v administration of carb showed similar changes in DA, GABA, and GLu, except the time to reach Cmax for DA as well as the changes in GABA, and GLu after i p administration occurred later. The elimination half-life of carb and the area under the curve (AUC) were similar after both routes of administration. It is concluded that carb must be formed from DSF before any changes in DA, GABA, and GLu in the NAc and mPFC are observed. DSF and carb, when administered to rats, co-release DA, GABA, and GLu. Carb, once formed can cross the blood brain barrier and enter the brain. Although inhibition of liver ALDH2 is the accepted mechanism for DSF’s action in treating AUDs, the concurrent changes in DA, GABA, and GLu in the NAc and mPFC after DSF administration suggest that changes in these neurotransmitters as a potential mechanism of action not only for AUDs, but also for cocaine dependence cannot be excluded

A Very Large Array 3.6cm continuum survey of Galactic Wolf-Rayet stars

We report the results of a survey of radio continuum emission of Galactic Wolf-Rayet stars north of declination -46 degrees. The observations were obtained at 8.46 GHz (3.6cm) using the Very Large Array (VLA), with an angular resolution of about 6 x 9 arcsec and typical rms noise of 0.04 mJy/beam. Our survey of 34 WR stars resulted in 15 definite and 5 probable detections, 13 of these for the first time at radio wavelengths. All detections are unresolved. Time variations in flux are confirmed in the cases of WR98a, WR104, WR105 and WR125. WR79a and WR89 are also variable in flux and we suspect they are also non-thermal emitters. Thus, of our sample 20-30% of the detected stars are non-thermal emiters. Average mass loss rates determinations obtained excluding definite and suspected non-thermal cases give similar values for WN (all subtypes) and WC5-7 stars, while a lower value was obtained for WC8-9 stars. Uncertainties in stellar distances largely contribute to the observed scatter in mass loss rates. Upper limits to the mass loss rates were obtained in cases of undetected sources or for sources which probably show additional non-thermal emission.Comment: 21 pages, Latex, 21 postscript figures, to be published in The Astronomical Journal, May 200

Hydraulic Conditions Leading To Exponential Mine Tailings Delta Profiles

A recent theoretical model of the subaerial deposition of mine tailings slurries predicts that the profile of a tailings delta formed with constant inputs will conform to an exponential curve. Both the profiles of and the particle sorting on one platinum and two coal tailings deltas have been shown to conform to the theoretical model, as have the profiles of three laboratory coal talings deltas. The profiles of a further eight metalliferous and two coal tailings deltas, with a wide range of input tailings parameters, are shown here also to conform to the exponential curve predicted by the theoretical model

Prediction of Mine Tailings Delta Profiles

The profile of a delta formed by fine-grained mineral processing wastes, disposed of as aqueous slurries by subaerial deposition from a pipeline, has a significant bearing on the volume that is available for waste and water storage in a given containment structure. Earlier field data and laboratory experiments suggested that mine waste delta profiles could be predicted with good accuracy using data from small-scale laboratory deposition tests. The relationships between the profiles of full-size and laboratory-model deltas are analysed using the principles of kinematic similarity and a recent theory of delta formation based on engineering hydraulics. Measured profiles of full-size and model coal-mine tailings deltas are compared and the prediction of full-size profiles is discussed. It is shown that the data derived from laboratory-model deltas are insufficient to enable accurate prediction of full-size delta profiles. Initial slope data or other, equivalent data for the full-size delta are also required