NQS

About: NQS is a research topic. Over the lifetime, 337 publications have been published within this topic receiving 4226 citations.

Determination of methamphetamine in urine samples with sodium 1, 2-naphthoquinone-4-sulphonate

Abstract: Optimal conditions have been studied for the determination of methamphetamine in urine samples by an extractive-spectrophotometric method with sodium 1,2-naphthoquinone-4-sulphonate (NQS) as reagent These conditions are: NaHCO3 pH 10, NQS 63 × 10−3 mol/l and heating for 5 min at 45°C The accuracy and precision of the method were tested The detection limits were 02 mg/l in the standard and 09 mg/l when 5 ml of urine sample were taken The standard deviation of blank urine was evaluated from 12 different samples The relative errors found in the determination of methamphetamine in urine were lower than 10% if the methamphetamine-amphetamine ratio was higher than 4

Charge-Carrier Velocity Distributions in High-Mobility Polymer Dual-Gate Thin-Film Transistors

Abstract: We report charge-carrier velocity distributions in high-mobility polymer thin-film transistors (PTFTs) employing a dual-gate configuration. Our time-domain measurements of dual-gate PTFTs indicate higher effective mobility as well as fewer low-velocity carriers than in single-gate operation. Such nonquasi-static (NQS) measurements support and clarify the previously reported results of improved device performance in dual-gate devices by various groups. We believe that this letter demonstrates the utility of NQS measurements in studying charge-carrier transport in dual-gate thin-film transistors.

Substituent effect of a fluorine atom on the mutagenicity of nitroquinolines

Abstract: Some 16 nitroquinolines (NQs) and their fluorinated derivatives were tested for mutagenicity in Salmonella typhimurium TA100 without S9 mix to investigate the effect of fluorine-substitution on the mutagenicity. These NQs consist of 5-NQs, 5-nitroquinoline N-oxides (5-NQOs), N-methyl-5-nitroquinolinium methanesulfonates (N-Me-5-NQs) and 8-NQs, including three ortho-F-NQs, one meta-F-NQ, four para-F-NQs and four 3-F-NQs. For this purpose, eight F-NQs were newly synthesized. The data indicated that the ratio of the mutagenic activities (revertants/plate/nmol) of fluorinated NQs to those of the corresponding parent non-fluorinated compounds ranged from 0.6- to 119-fold. The fluorine atom located para to the nitro group markedly enhanced the mutagenicity (24-fold and more), while three ortho-fluorinated derivatives showed no significant increase in mutagenicity (enhancement ratio were 0.6, 0.8 and 1.7). With respect to 8-NQs, its meta-fluorinated derivative also had an enhanced mutagenicity over the parent compound (53-fold). In addition, although N-Me-5-NQ was less mutagenic than 5-NQ and 5-NQO, the mutagenicity of N-Me-5-NQ was most significantly enhanced by fluorine-substitution. These results suggest that introduction of a fluorine atom to the molecule in question may be a useful tool to modify their mutagenic potency and to better understand the mechanism of mutation.

Analytical turn-off current model for type of conductivity modulation power MOSFETS with extracted excess carrier

Abstract: An analytical transient turn-off current model for a type of the conductivity modulation power MOSFET transistors (CMT) with the extracted structure of the excess carrier is developed in the paper. With the non-quasi-static state (NQS) approximation for the excess carrier in the wide base of a low gain pnp transistor included in the CMT the three state equations of the charge, the voltage and the current are solved for the transient turn-off current analysis and ambipolar transport theory in high-level injection is used to evaluate the steady state current. Accounting for the perturbing effect of the carrier concentration redistribution under the condition of base width modulation and the coupling effect between the electron and hole current, the normalized transient current and turn-off time of the device with the extracted structure are obtained and compared with the experimental results.

Kinetic-spectrophotometric determination of primary and secondary amines by reaction with 1-2 naphthoquinone-4-sulphonate

Abstract: A kinetic-spectrophotometric method for the determination of primary and secondary amines is described. It is based on the coloured reaction of these amines with sodium 1,2 Naphthoquinone 4-sulphonate (NQS) in the presence of a non-ionic surfactant. For each determination the optimum conditions were studied and found to be as follows: pH 10.5. Carbonate-bicarbonate buffer 0.1M, Triton X-100 0.1%, Temperature 45°C, and NQS 6.4 × 10−3 M and interval of time 45–180s at wavelength 490 nm. The parameters used for the quantitative determinations are the reaction rate and the increase in the absorbance of the kinetic curves. This procedure has been applied to the determination of ephedrine and amphetamine in pharmaceutical samples.