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Dec 2021 DOI 10.14302/issn.2766-8681.jcsr-21-3805
Adiche ChiaaCorresponding author
Laboratory of Fine Chemistry (L.F.C), Chemistry Department, Faculty of Exact and Applied Sciences University of Oran 1 Ahmed BenBella BP 1524 El M’naouer Oran 31000 Algeria.
A convenient one-pot synthetic protocol for the preparation of sulfonyl amidines has been developed. The procedure combines three-component reaction of sulfonyl azide, methyl propiolate and secondary cyclic amine coupling in one sequence without any solvent or catalyst and at room temperature. The reaction proceeds smoothly and a variety of desired sulfonyl amidines were obtained in moderate to good yields. This protocol has synthetic advantages in terms of low environmental impact and very short reaction time.
Jan 2020 DOI 10.14302/issn.2379-7835.ijn-19-3139
Q. Almulaiky YaaserCorresponding author
Chemistry Department, Faculty of Sciences and Arts, University of Jeddah, Khulais, P.O. Box 355, Khulais, 21921, Saudi Arabia
In this study, a peroxidase from new source was purified using ion exchange and gel filtration techniques. The recovery for peroxidase activity was 19% with 11-fold purification and specific activity of 749 unit/mg protein. Purified peroxidase demonstrated a molecular mass of 39 kDa using gel filtration and was confirmed as a single band on SDS-PAGE. The purified peroxidase revealed a broad optimum pH activity at 6.0-6.5 and 50°C temperature. The kinetic parameters for purified peroxidase toward H2O2 and guaiacol as substrates were found to be Km = 3.355, 5.395 mM, Kcat = 99.52, 79.56 s-1 and Vmax =1.531, 1.242 µmole ml-1 min-1, respectively. The catalytic efficiency (kcat/Km) of the purified peroxidase was 14.75 and 29.66 s−1 mM−1 for guaiacol and H2O2, respectively. Peroxidase activity was observed to be enhanced by Cu2+, Co2+, Ni2+ and inhibited in the presence of Sn2+, Al3+, Hg2+, NaN3, EDTA and urea. Characterization showed that peroxidase purified from C. forskohlii has the ability to be used for food industrial applications.
Mar 2019 DOI 10.14302/issn.2643-0282.imsj-19-2672
Fadel Madkour FedekarCorresponding author
Marine Science Department, Faculty of Science, Port Said University, Port Said, Egypt
Recently, annual swarm of invasive Erythrean schyphozoan RhopilemanomadicaGalil, 1990 appeared along Egyptian Mediterranean coasts causing beach closures and fishing problems. The present study conducted survey and field monitoring on R. nomadica during blooming season in the Egyptian Mediterranean coast throughout three consecutive years (2015-2017). Three main features of R. nomadica bloom were addressed; viz starting date, duration and maximum density of aggregation. In 2015, the bloom started on 28 July, and over the following two years the bloom starting date shifted earlier being 19 July in 2016 and 15 June in 2017. The duration of the bloom varied yearly giving the longest duration in 2017 when the bloom continued in high density for a month. The highest density of R. nomadica was about 896 medusae/1000 m3 in 2017. The medusae diameter ranged between 21 to 112 cm. The average bell diameter for each year displayed gradual increasing values over the years. The consistent annual R. nomadica blooming was attributed to the high level of eutrophication and ecosystem degradation occurred along the Mediterranean coast since last decades. The shifting in the annual bloom starting date and duration may reflect the adaptation of R. nomadica to the climate change effect on the Mediterranean Sea temperature.
Sep 2018 DOI 10.14302/issn.2689-2855.jan-18-2342
Belousov AndreyCorresponding author
Laboratory of Applied Nanotechnology of Belousov.
This study was devoted to the learning of the use of nanotechnology to correct the functional activity of red blood cells (RBCs) at the storage stages at a positive temperature. It was established that saline NaCl, which had previously been processed by magnetite nanoparticles (ICNB) had a marked membrane-stabilizing effect, inhibits hemolysis and increasing the sedimentation stability of preserved RBCs. The complex analysis of the obtained data allowed to determine the primary mechanisms effect of the saline NaCl, which had previously been processed by ICNB on the preserved RBCs. The proposed method of additive modernization of preserved RBCs was adapted to the production process. The optimization results were obtained in creating a simple and practical method of additive modernization of preservation solutions that does not violate the compliance requirements, improves the quality, efficiency and safety transfusion of RBCs.
Jul 2018 DOI 10.14302/issn.2642-3146.jec-18-2232
Aljerf LoaiCorresponding author
Department of Basic Sciences, Faculty of Dental Medicine, Damascus University, Damascus, Syria
Critical conditions are usually obtained for ignition in a self-heating solid system consisting of two components generating heat independently, one component being inexhaustible and the other exhaustible by either simple first order or autocatalytic reaction. Ignition depends upon whether the exhaustible component can cause a temperature rise in excess of the upper stationary, but unstable, value possible for the inexhaustible component reacting alone. The system provides a theoretical model for some commonly occurring examples of self-heating and ignition in porous solids containing oxidisable oils. It is shown that: (a) the ignition criterion of the model, which involves a nonarbitrary critical temperature increase, has a high degree of physical reality; (b) the model is, in principle, capable of predicting ignition from primary kinetic and thermal data; (c) it is likely to be possible often to make a reliable prediction of critical size for self-ignition in a two-component system at ordinary atmospheric temperatures by a simple extrapolation from small-scale ignition data, obtained at higher temperatures, in the same way as for ignition due to a single reaction. Examination of both adiabatic and non-adiabatic flame theories showed that a 'steady state' exists only under the special condition that a heat sink exists at the initial temperature. For the general case of freely propagating, non-adiabatic flames only a quasi-steady state can be achieved.
Dec 2017
Aljerf LoaiCorresponding author
Department of Life Sciences, Faculty of Dentistry, University of Damascus
p-hydroxybenzoic acid esters are used as food and drug preservatives. These compounds were quantised by a reversed-phase thin-layer chromatography method based on the use of silanized silica gel as stationary phase. Thin layers chromatography of silanized silica gel (HF254) is implemented to separate p-hydroxybenzoic acid and its methyl, ethyl, propyl, butyl and benzyl esters. Borate buffer (pH 2) was used as a mobile phase with the addition of organic solvent as required. For the quantitative determination, the solutions to be analysed were applied in bands on 5 x 20 cm plates. The plates are developed in glass chromatography chambers lined with filter paper. After the plates have been developed they are dried at room temperature. The spots or bands of the various compounds are visualised under a 250-mµ UV light source. The extraction of the silica gel with methanol was effective. Six preservatives were separated with better results for benzyl- and butyl-p-hydroxybenzoates. Chromatographic development controlled by temperature stability in the chromatographic chamber and spectrophotometric determination of all the compounds were indicated. A second development with the same solvent mixture was suggested especially when low RF is involved. Various compounds are completely separated and a good determination of p-hydroxybenzoic acid and its principle esters are possible using a simple technique of elution and spectrophotometric determination.