ONLINE OXIDATION OF CR(III) TO CR(VI) FOR USE WITH THE FLOW-INJECTION ANALYSIS TECHNIQUE

109564564

SPECTROPHOTOMETRIC DETERMINATION OF BORON IN PLANTS USING MONOSEGMENTED CONTINUOUS-FLOW ANALYSIS

113228929

Motor Deficits and Decreased Striatal Dopamine Receptor 2 Binding Activity in the Striatum-Specific Dyt1 Conditional Knockout Mice

DYT1 early-onset generalized dystonia is a hyperkinetic movement disorder caused by mutations in DYT1 (TOR1A), which codes for torsinA. Recently, significant progress has been made in studying pathophysiology of DYT1 dystonia using targeted mouse models. Dyt1 ΔGAG heterozygous knock-in (KI) and Dyt1 knock-down (KD) mice exhibit motor deficits and alterations of striatal dopamine metabolisms, while Dyt1 knockout (KO) and Dyt1 ΔGAG homozygous KI mice show abnormal nuclear envelopes and neonatal lethality. However, it has not been clear whether motor deficits and striatal abnormality are caused by Dyt1 mutation in the striatum itself or the end results of abnormal signals from other brain regions. To identify the brain region that contributes to these phenotypes, we made a striatum-specific Dyt1 conditional knockout (Dyt1 sKO) mouse. Dyt1 sKO mice exhibited motor deficits and reduced striatal dopamine receptor 2 (D2R) binding activity, whereas they did not exhibit significant alteration of striatal monoamine contents. Furthermore, we also found normal nuclear envelope structure in striatal medium spiny neurons (MSNs) of an adult Dyt1 sKO mouse and cerebral cortical neurons in cerebral cortex-specific Dyt1 conditional knockout (Dyt1 cKO) mice. The results suggest that the loss of striatal torsinA alone is sufficient to produce motor deficits, and that this effect may be mediated, at least in part, through changes in D2R function in the basal ganglia circuit

The use of the modified simplex as an optimization strategy in analytical chemistry.

The multivariate optimization designs most used in analytical chemistry are presented, with a particular focus on the Modified Simplex Method. The sequential movements for this procedure are described in detail by means of an hypotetical example and its application is discussed by using a 3-variable chemical system, where the analytical response, taken as the difference in absorbance, Delta A, due to the absorbance readings of the Mo(VI) catalysed and non catalysed (blank) oxidation of iodide ions with hydrogen peroxide in acid medium, are related to the concentrations of the reagents involved, Other examples from the literature are also cited.191242

Experimental design for mixtures using paper chromatography.

The present paper presents the theoretical aspects of experimental designs for mixtures and illustrates its application to determine the best mobile phase composition of the paper chromatographic separation of two dyes, The statistical treatment of the data requires a basic knowledge of the subject and a microcomputer with a MATLAB (or similar) computational package.19331331

A CONTINUOUS-FLOW COLD VAPOR PROCEDURE FOR MERCURY DETERMINATION BY ATOMIC-EMISSION USING THE REVERSE FLOW-INJECTION APPROACH

An experimental set-up for on-line Hg2+ reduction and determination was devised using the reverse flow injection analysis (r-FIA) concept and the cold vapour (CV) technique, injecting an acidic Sn2+ solution into the mercury sample line. The elemental mercury generated is separated from the reacting mixture by a 100 mi min(-1) helium stream, which passes through a gas-liquid separator connected to a permeation cell. This gas stream is used as the plasma medium. The permeated Hg-o is then concentrated on a 0.3 g gold foil placed inside a quartz tube connected to an 11 W He de discharge plasma chamber. The mercury retained on the gold surface is released by resistive heating and the emission intensity is observed at the 253.7 nm mercury line. For an injection cycle of 30 s, the calibration graphs are linear up to 50 ng mi(-1) (P = 0.999). An injection frequency of 120 h(-1) is achieved, with negligible carry-over. The calculated relative standard deviation of the transient peaks is 1.6%. Higher sensitivities can be achieved using longer injection cycles. Samples of Human Hair Certified Reference Material were used to determine the accuracy of the method.49878779

SIMPLE DIGITAL COUNTER FOR USE WITH MONOSEGMENTED CONTINUOUS-FLOW ANALYSIS AND RELATED TECHNIQUES

113229529

A FLOW-INJECTION HYDRIDE GENERATION SYSTEM FOR THE DETERMINATION OF ARSENIC BY INDUCTIVELY-COUPLED PLASMA ATOMIC EMISSION-SPECTROMETRY

161JUL27528

HIGH-PERFORMANCE MODULAR SPECTROPHOTOMETRIC FLOW CELL

A high-performance modular flow cell is described, which can be used in photometric or spectrophotometric detector systems for analytical and preparative scale low-pressure liquid chromatography, flow injection and related techniques. The basic design is that of an inner absorption cell unit sandwiched between two rugged supports. The novel aspects of this sandwiched cell are the wide range of interchangeable flow cell units of different dimensions that can be used, and the way in which the fluid flow occurs, essentially eliminating problems with gas bubbles and giving rapid cell clearance. The cell is compact and its versatility is enhanced by using optical fibre bundles to transmit the light beam to the optical path of the cell and then from there to the detector.116990590