Part 14. Synthesis and properties of new polyketoamine polymers containing cycloalkanone moieties in the main chain

A new interesting class of polyketoamine polymers based on diarylidenecycloalkanone were synthesized by suspension polycondensation. These polymers were synthesized via polymerization of 2,5‐bis(4‐chloroacetylbenzylidene)cyclopentanone and 2,6‐bis(4‐chloroacetylbenzylidene)cyclohexanone with different aliphatic and aromatic diamines including, p‐phenylenediamine, m‐phenylenediamine, o‐phenylenediamine, 4,4′‐diaminodiphenylmethane, 4,4′‐diaminodiphenylether, 4,4′‐diaminodiphenylsulfone, hydrazine hydrate, 1,2‐diaminoethane, 1,3‐diaminopropane and 1,8‐diaminooctane. Model compounds were prepared by condensation of 2,5‐bis(4‐chloroacetylbenzylidene)cyclopentanone and/or 2,6‐bis(4‐chloroacetylbenzylidene)cyclohexanone with aniline in dry benzene, and their structure was confirmed by elemental analysis and spectroscopy. The structure of the polymers obtained was also confirmed by the same methods. Moreover, the identification of the polymers was carried out by other techniques, eg crystallinity from X‐ray spectroscopy, viscosimetry, thermogravimetric analysis; the morphological properties of selected examples were tested by scanning electron microscopy. The electrical conductivity of selected examples is about 10^?12 ohm cm^?1. The results are in accord with the structure. © 2002 Society of Chemical Industry     

Synthesis of Novel 2-Thiouracil-5-Sulfonamide Derivatives as Potent Inducers of Cell Cycle Arrest and CDK2A Inhibition Supported by Molecular Docking

In an effort to discover potent anticancer agents, 2-thiouracil-5-sulfonamides derivatives were designed and synthesized. The cytotoxic activity of all synthesized compounds was investigated against four human cancer cell lines viz A-2780 (ovarian), HT-29 (colon), MCF-7 (breast), and HepG2 (liver). Compounds 6b,d–g, and 7b showed promising anticancer activity and significant inhibition of CDK2A. Moreover, they were all safe when tested on WI38 normal cells with high selectivity index for cancer cells. Flow cytometric analysis for the most active compound 6e displayed induction of cell growth arrest at G1/S phase (A-2780 cells), S phase (HT-29 and MCF-7 cells), and G2/M phase (HepG2 cells) and stimulated the apoptotic death of all cancer cells. Moreover, 6e was able to cause cycle arrest indirectly through enhanced expression of cell cycle inhibitors p21 and p27. Finally, molecular docking of compound 6e endorsed its proper binding to CDK2A, which clarifies its potent anticancer activity.     

Novel Green Corrosion Inhibitor for Mild Steel in Sulfuric Acid

Protection of Metals and Physical Chemistry of Surfaces - Salix leaves water extract was studied for the corrosion inhibition of mild steel in H2SO4 at different temperatures. Energy dispersive...     

Effects of Electrical Stimulation on Histochemical Muscle Fiber Staining, Quality, and Composition of Camel and Cattle Longissimus thoracis Muscles

ABSTRACT:  The effects of electrical stimulation on muscle fiber type, meat quality, and composition of Longissimus thoracis muscles from one-humped camels and Dofari Omani cattle of a comparable age range were investigated. A low-voltage electrical stimulation with 90 V, 14 Hz (pulse of 7.5-millisecond duration every 70 milliseconds) 20 min postmortem was applied. Samples from the left muscle were collected from 20 (2 to 3 y) camels and 24 cattle (1 to 3 y). For chemical composition, muscle samples were dried in a freeze dryer, and then ground to determine moisture, protein, fat, and ash. Macro- and micro-minerals were determined using an Inductively Coupled Plasma Emission Spectrometer. Quality characteristics of the meat were evaluated using shear force value, pH, sarcomere, myofibrillar fragmentation index, expressed juice, cooking loss percent, and CIE L *, a *, b * color values. Electrical stimulation resulted in a significantly ( P < 0.05) more rapid pH fall in the muscle during the first 24 h after slaughter in both species. Muscles from electrically stimulated carcasses had significantly ( P < 0.05) lower ultimate pH, longer sarcomere, and lower shear force values than those from nonstimulated carcasses. Lightness ( L *), myofibrillar fragmentation, and expressed juice were significantly ( P < 0.05) higher for stimulated than for nonstimulated muscles. Muscles of camels had significantly ( P < 0.05) higher expressed juice, cooking loss percent, redness color ( a *), and lower fat, Mg, K, and P than those from cattle. Electrical stimulation improved quality characteristics of meat from both species. This indicates that meat quality of local camel and cattle can be improved by electrical stimulation and consequently improves their acceptability to consumers and better marketability.     

An evaluation of the growth, carcass and meat quality characteristics of Omani goat breeds

Body weight, growth, carcass and meat quality characteristics were evaluated in three breeds of goats (Batina, Dhofari and Jabal Akdhar) in Oman. Fourteen intact male goats from each breed were used. Jabal Akdhar goats had significantly heavier slaughter, empty body, and carcass weights and higher growth rates than Dhofari and Batina goats. Jabal Akdhar goats had significantly heavier internal organs than the other two breeds. Dressing-out percent (based on empty body weight) of goats ranged between 53 and 57%, with the Dhofari goats having the highest value. Longissimus muscle dimensions varied between the three breeds, with Jabal Akdhar having a significantly larger area than Batina with Dhofari in between. Dhofari goats produced significantly shorter and wider carcasses than Batina and Jabal Akhdar goats. Carcass cuts were significantly heavier in Jabal Akdhar than the other two breeds. Four muscles (Mm. longissimus dorsi, biceps femoris, semitendinosus, and semimembranosus) from both sides of each carcass were subjected to two different ageing periods (1 day vs. 6 day) and evaluated for ultimate pH, expressed juice, percent cooking loss, colour (L*, a* and b*), and Warner-Bratzler shear force. Breed had a significant influence on pH and percent cooking loss but not on expressed juice, shear force value and colour (CIE L*,a*, b* values). Muscles from the Batina goats had significantly higher ultimate pH values and lower percent cooking loss than Dhofari and Jabal Akdhar goats. Ageing from 1 to 6 days increased tenderness significantly (27%), but decreased cooking loss by 5%.     

Ultrasonic scanning measurements of the longissimus thoracis et lumborum muscle to predict carcass muscle content in sheep

Nineteen Omani sheep (average 26 kg body weight) were scanned over the 6th rib, 12th rib and the second-last lumbar vertebra, to determine the maximum depth (B), circumference, area of the cross-section and volume of the longissimus thoracis et lumborum (LD) muscle. The volume of the muscle was estimated by multiplying the average area of its cross-section obtained at the three sites by its length. After slaughter, the LD muscle was dissected out, frozen, and its maximum depth, circumference, length, weight and volume were determined. Correlation and regression analyses were carried out to evaluate relationships between scanning and real measurements and between scanning measurements and carcass total muscle content. Generally there were positive correlations (r = 0.43-0.66) between the LD scanning measurements made at the 12th rib and the corresponding measurements made on the dissected muscle. The volume of the LD muscle estimated from scanning was positively correlated (r = 0.59) with its real volume which was correlated with its weight (r = 0.51) and consequently with the total carcass muscle content (r = 0.69). Ultrasonic scanning can be used to predict the circumference and volume of the LD muscle. These may be used for prediction of total carcass muscle content in sheep in addition to traditional measurements of the muscle (the maximum depth B) and area.     

Chemical composition,quality and histochemical characteristics of individual dromedary camel (Camelus dromedarius) muscles

This study characterized the chemical composition, quality and histological traits of six muscles from 10 dromedary carcasses. There were significant differences in moisture, fat, protein, mineral, saturated and unsaturated fatty acid contents between muscles. The longissimus thoracis (LT) had the highest cooking loss (33.5%) and triceps brachii (TB) the lowest (29.2%). The shear force value of semitendinosus (ST), semimembranosus (SM) and biceps femoris (BF) were significantly higher than infraspinatus (IS), TB and LT. The LT had significantly higher values for L*, a*, b* than ST. The SM had the lowest MFI (65.3), while IS had the highest value (75.8). The ST significantly had the highest and lowest proportions of Type I and Type IIA muscle fibers, respectively than other muscles. This study indicated that composition, quality, and histochemical parameters varied among camel muscles and the knowledge of this variation allows for better marketing and processing of camel meat.     

Corrosion inhibition of steel in crude oil storage tanks

The corrosion behavior of steel in water from certain oil fields with various organic inhibitors was studied by applying potentiodynamic technique at pH 5.9. The inhibitors which were used include 2‐methylbenzimidazole (I), 2‐mercaptobenzimidazole (II), 2‐mercapto‐5‐methylbenzimidazole (III), and 2‐mercaptothiazole (IV). The inhibiting efficiency of the different additives was evaluated from their anodic and cathodic polarization curves at different temperatures. A comparative study of curve fitting procedures using the kinetic thermodynamic model and those utilizing well‐known adsorption isotherms was undertaken. Three types of isotherms were used, Langmuir, Frumkin and Flory‐Huggins isotherm. The results show that the kinetic‐thermodynamic model and Flory‐Huggins isotherms are more suitable to fit the data for the four inhibitors, at all applied temperatures. From the values of binding constants, K, the order of inhibitor efficiency is: III > IV > II > I and thus 2‐mercapto‐5‐methylbenzimidazole was the most effective inhibitor. The thermodynamic parameters obtained for all the compounds used showed low values of H_ads, which indicates that the action of these inhibitors is physically adsorptive in nature.     

Redox regulation of signal transduction in smooth muscle cells: distinct effects of PKC-down regulation and PKC inhibitors on oxidant induced MAP kinase

Reactive oxygen species function as signaling molecules, and are known to be generated under both normal and pathological conditions. Using vascular smooth muscle cells, we have demonstrated an increase in mitogen activated protein kinase activity in response to oxidants. Mitogen activated protein kinase activity increased linearly with time in cells treated with pervanadate. Hydrogen peroxide also caused rapid induction of mitogen activated protein kinase. Protein kinase C down regulation partially decreased induction of mitogen activated protein kinase activity by oxidants, and the Ca2+ ionophore, ionomycin. Protein kinase C inhibitors, compound-3 and bisindolylmaleimide did not inhibit oxidant induced mitogen activated protein kinase activity, where as calphostin C activated it. The tyrosine kinase inhibitors genistein, herbimycin A and tyrphostin caused 50% inhibition of oxidant induced mitogen activated protein kinase activation. These results suggest that oxidant-induced mitogen activated protein kinase is protein kinase C independent.