Comparative study of microwave assisted and conventional synthesis of novel 2-quinoxalinone-3- hydrazone derivatives and its spectroscopic properties

A series of novel quinoxalin-2(1H)-one-3-hydrazone derivatives, 2a - 8d were synthesized via condensation of 3-hydrazinoquinoxalin-2(1H)-one, 1, with the corresponding ketones under microwave irradiation. The microwave assisted reaction was remarkably successful and gave hydrazones in higher yield at less reaction time compared to conventional heating method. The chemical structures of the compounds prepared were confirmed by analytical and spectral dat

Microwave-Assisted Synthesis and Antibacterial Activity of some Pyrazol-I-Ylquinoxalin-2(IH)-One Derivatives

3-Hydrazinoquinoxalin-2(1H)-one was prepared from quinoxaline-2,3-dione and subsequently used for the synthesis of some potentially biologically active 3-(pyrazol-1-ylquinoxalin-2(1H)-one derivatives. While 3-(3,5-dimethylpyrazol-1-yl)quinoxalin-2(1H)-one showed a comparative effect with streptomycin, 3-(5-oxo-3-phenyl-4,5-di- hydropyrazol-1-yl)quinoxalin-2(1H)-one was found to be the most active at MIC value of 7.8 μg/m

Design and Construction of a Pure Sine Wave Inverter

This research is a design and implementation of a sine wave inverter circuit developed to run AC appliances at a low cost which high efficiency. The design consists of two stages i.e. the DC-DC step up stage and a DC-AC Inverter stage. The DC-DC step up converter is based on a push-pull design to step 24VDC to 300VDC. Pulse width modulation was used i.e. the SG3525 pulse width Modulator. The DC-AC inverter stage comprised of four power mosfets in an H-bridge configuration, driven by a 40 kHz square wave encoded/modulated by a 50Hz sine wave that was derived from a TL084 quad op amp sine wave oscillator. An output voltage range of about 240-260VAC from 300VDC input was obtained. A low pass filter was used to filter out the high frequencies and thus isolate the harmonics so a 50 Hz fundamental frequency was retained

Microwave assisted synthesis and antimicrobial activity of 2-quinoxalinone-3-hydrazone derivatives

A simple and efficient method has been developed for the synthesis of various 2-quinoxalinone-3-hydra-zone derivatives using microwave irradiation technique. The series of 2-quinoxalinone-3-hydrazonederivatives synthesized, were structurally confirmed by analytical and spectral data and evaluated fortheir antimicrobial activities. The results showed that this skeletal framework exhibited marked potencyas antimicrobial agents. The most active antibacterial agent was 3-{2-[1-(6-chloro-2-oxo-2H-chromen-3-yl)ethylidene]hydrazinyl}quinoxalin-2(1H)-one,7while 3-[2-(propan-2-ylidene)hydrazinyl]quinoxalin-2(1H)-one,2appeared to be the most active antifungal agen

Distribution of radionuclides and assessment of risk exposure to the miners on a kaolin field

Mining of kaolin deposits are common in Nigeria without considering the background radiation in such environment and the health risks it might pose on the miners. In this study, in-situ measurements of the naturally occurring radionuclides were carried out with the aim of determining the distribution of these radionuclides on the mining field and estimation of the hazard indices exposure risks (γ- and α-radiation risks) to the miners. The study was achieved with the aid of gamma ray detector Super-Spec (RS-125) and global positioning system. The detector used has ability to measure activity concentrations of 238U, 232Th and 40K and gamma doses. For the purpose of this study, only the concentrations of the three radionuclides were considered. For each location, measurements were taken four times, while its mean value was estimated for better accuracy. In all, nineteen locations were occupied in order to cover the study area. Basic kriging method was adopted for the production of spatial distribution of these radionuclides and their corresponding γ- and α-radiation hazard indices. The mean values of 238U, 232Th and 40K are 46.7, 71.8 and 108.7 Bq kg-1 , respectively. When compared to the global standard, it was revealed that 238U and 232Th are greater than the global standard, while 40K fall below the permissible limit. The γ- and α-radiation exposure risks estimated revealed that the mean values of Iγ and Iα are 0.6 and 0.2 respectively. Though the estimated γ- and α-radiation indices showed that the kaolin field is safe for the miners, periodic check is required in order to monitor the rate at which these natural primordial radionuclides (238U and 232Th and their progenies) are being enhanced

MICROWAVE-ASSISTED SYNTHESIS AND ANTIBACTERIAL ACTIVITY OF SOME PYRAZOL-1-YLQUINOXALIN- 2(1H)-ONE DERIVATIVES

3-Hydrazinoquinoxalin-2(1H)-one was prepared from quinoxaline-2,3-dione and subsequently used for the synthesis of some potentially biologically active 3-(pyrazol-1-yl)quinoxalin-2(1H)-one derivatives. While 3-(3,5-dimethylpyrazol1-yl)quinoxalin-2(1H)-one showed a comparative effect with streptomycin, 3-(5-oxo-3-phenyl-4,5-di- hydropyrazol 1-yl)quinoxalin-2(1H)-one was found to be the most active with an MIC value of 7.8 μg/ml

Distribution of radionuclides and assessment of risk exposure to the miners on a kaolin field

Mining of kaolin deposits are common in Nigeria without considering the background radiation in such environment and the health risks it might pose on the miners. In this study, in-situ measurements of the naturally occurring radionuclides were carried out with the aim of determining the distribution of these radionuclides on the mining field and estimation of the hazard indices exposure risks (γ- and α-radiation risks) to the miners. The study was achieved with the aid of gamma ray detector Super-Spec (RS-125) and global positioning system. The detector used has ability to measure activity concentrations of 238U, 232Th and 40K and gamma doses. For the purpose of this study, only the concentrations of the three radionuclides were considered. For each location, measurements were taken four times, while its mean value was estimated for better accuracy. In all, nineteen locations were occupied in order to cover the study area. Basic kriging method was adopted for the production of spatial distribution of these radionuclides and their corresponding γ- and α-radiation hazard indices. The mean values of 238U, 232Th and 40K are 46.7, 71.8 and 108.7 Bq kg-1 , respectively. When compared to the global standard, it was revealed that 238U and 232Th are greater than the global standard, while 40K fall below the permissible limit. The γ- and α-radiation exposure risks estimated revealed that the mean values of Iγ and Iα are 0.6 and 0.2 respectively. Though the estimated γ- and α-radiation indices showed that the kaolin field is safe for the miners, periodic check is required in order to monitor the rate at which these natural primordial radionuclides (238U and 232Th and their progenies) are being enhanced

Functional bioactive compounds in ginger, turmeric, and garlic

Nutrition plays a very important role in the health promotion of individuals and brought about a global paradigm shift from pharmaceuticals to nutraceuticals. This is due to the high cost, non-availability, and side effects associated with the unregulated consumption of pharmaceuticals. Over the ages, nutraceuticals from food products were reported to contain bioactive compounds with great health and physiological benefits. This report reviews bioactive compounds in selected foods namely ginger (Zingiber officinale), turmeric (Curcuma longa), and garlic (Allium sativum) as potential natural therapeutics for ailments of cancer and heart-related diseases. Analytical profiles, functional activities, and characterization of these compounds were discussed with possible recommendations for the prospective treatment of diseases using these nutraceuticals