Synthesis and characterization of new chromeno[2,3-b]pyridines via the Friedländer reactions of 8-allyl-2-amino-4-oxo-4H-chromene-3-carboxaldehyde

New series of chromeno[2,3-b]pyridines, 2-8, have been obtained from 1,8-diazabicyclo [5.4.0]undec-7-ene catalyzed Friedländer reaction of 8-allyl-2-aminochromone-3-carboxaldehyde (1) with some carbonyl compounds containing a reactive α-methyl or methylene group namely 2-acetylthiophene, 3-acetylpyridine, 4-chloroacetophenone, 4,6-diacetylresorcinol, acetylacetone, dibenzoyl methane and acetoacetanilide. Heteroannulated chromones, 13-16, were prepared from Friedländer reaction of 1 with some cyclic α-methylene ketones namely 2-phenyliminothiazolidin-4-one, pyrazoline-3,5-dione, 5,5-dimethylcyclohexane-1,3-dione and thiobarbituric acid. Structures of the newly synthesized compounds have been established from elemental analysis and spectroscopic data

Two spectrophotometric methods for the determination of azithromycin and roxithromycin in pharmaceutical preparations

Two new and simple spectrophotometric procedures have been proposed and validated for estimation of two important macrolide antibiotics namely, azithromycin dihydrate and roxithromycin. Method I depends on complex formation between any of the two drugs and copper in acidic medium where the absorbances of the produced complexes are measured at 250 and 264 nm with linearity ranges of 1.0-100.0 and 2.0-130.0 µg/mL for the two drugs, respectively. Method II depends on the reaction of these drugs with N-bromosuccinimide forming a product which is yellow colored, measured at 264 and 278 nm, with linearity ranges of 2.0-140.0 and 3.0-160.0 µg/mL for azithromycin dihydrate and roxithromycin, respectively. The proposed methods were subjected to detailed validation procedure; moreover they were used for the estimation of the concerned drugs in their different dosage forms. Study of the reactions stoichiometry was carried out; furthermore, a reaction mechanism proposal was presented

Microgrid Enabling Towards the Implementation of Active Distribution Systems: Planning, Operation, and Energy Trading

Recent years have perceived a substantial surge in interest in green technologies due to the growing awareness about the environmental concerns and the technologies’ development, which have resulted in considerable utilization of DC-based distributed generators (DGs) and loads such as photovoltaic (PV) panels and electric vehicles. This increased penetration has reformed the generation and utilization of electric, resulting in promoting the microgrids (μGs) as a promising candidate for future systems. Despite the well-establishment and the extensive studies of μGs, there is still some debate over having μGs that are purely AC, purely DC, or AC-DC hybrid. Purely AC and purely DC configurations cannot meet the challenges and the new technologies that are expected to emerge in the near future as they require many interfacing converters to accommodate the high penetration of DC DGs and loads. These interfacing converters increase the system costs, the conversion losses, and the system complexity. The aforementioned reasons have resulted in the consensus tending towards a new vision of combining the AC and DC to acquire the benefits of both systems, which calls for further investigation of the AC-DC system compositions. The growing electricity demand, aging of the power system infrastructure, and countries effort to utilize renewable-based DGs have stimulated the concept of isolated μGs.Isolated μGs could allow utilities and developers to defer the installation of new generation capacities, in addition to transmission and distribution capacities upgrades by connecting distributed energy resources. Despite the significant benefits provided by isolated μGs, preserving load-generation balance is comprehensively challenging, given that μGs are dominated by renewable-based DGs, which are characterized by their probabilistic nature and intermittent power. This challenge introduced the interconnection of μGs as a promising solution that enhance the system operation and increase the system reliability. The interconnection of a group ofμGs essentially leads to a (small scale) energy market of interconnected microgrids (IμGs) when these μGs exchange energy with each other. Therefore, it is vital to refine and enhance the way in which players from different μGs construct the interconnected μGs and manage electricity trading. Driven by the aforementioned challenges, the main objective of this thesis is to promote the concept of μG and optimally accommodate the expected increased penetration of DC DGs and DC loads in future systems, and ensure the continuity of power supplied to these future systems through their interconnection and managing the energy trading process. Achieving this target entailed the completion of the following parts: 1) Proposing the bilayer μGs configuration, in addition to its power flow model, at which each node is a universal node that can include two buses with different types of power (AC and DC) or a single bus (AC or DC). The inclusion of the two types of power reduces the number of interfacing converters and allows for the accommodation of the increased penetration of DC DGs and loads besides the existing conventional AC DGs and loads. 2) Proposing a stochastic planning framework for the network configuration of AC-DC bilayer μGs that is capable of minimizing the total system costs through the determination of the optimal BμGconfiguration. 3) Investigating the AC-DC bilayer μGs operation under fault conditions and introducing a multilevel converter with fault confining capability that can isolate the faulty layer, and hence ensures optimal and reliable operation of the healthy layer under fault conditions. 4) The proposal of a stochastic planning framework for the IμGs that minimizes the total system costs and minimizes the loads curtailment under DG failure, while considering the stochastic variations of the renewable-based DGs and loads. 5) Developing an energy trading mechanism that facilitates the power trading between the interconnected μGs, provides full utilization of the renewable output power, minimizes operation cost, and minimizes load curtailment

1,2,4-Triazine Chemistry Part II: Synthetic approaches for phosphorus containing 1,2,4-triazine derivatives

This review represents the methods developed for the synthesis of phosphorus containing 1,2,4-triazine moieties. These methods depends on the phosphorylation of side functional groups of 1,2,4-triazines and cyclization of side functional groups of 1,2,4-triazines with phosphorus reagents to give isolated and fused phosphorus heterocyclic systems

Serum IL-21 level and its relation to activity and severity of alopecia areata

Background: Alopecia areata (AA) is a non-cicatricial alopecia that is postulated to be a hair-specific autoimmune disease, with genetic factors playing a role in disease susceptibility and severity. The disease presentation ranges from circular patches on the scalp to complete hair loss with devastating psychosocial consequences.Patients and methods: This was a case control study carried out on 40 patients diagnosed as alopecia areata. They were recruited from the outpatient clinic of Dermatology, Andrology and STDs Department, Mansoura University Hospitals. In addition 40 normal healthy subjects with matched age and sex were selected to act as a control group.Results: Serum levels of IL-21 were significantly increased in AA patients, and showed significant positive correlation with activity of the disease. Higher serum levels of IL-21 in active cases support its role as predictor of disease activity. There were no significant differences in IL-21 level with different SALT scores. Receiver Operating Characteristic (ROC) curve analysis of IL-21 was conducted to evaluate the sensitivity and specificity of serum IL-21 as a diagnostic index for AA. The AUC-ROC of IL-21 was excellent (0.962); and the best cut off point for IL-21 was determined to be 22.22 pg/ml. It was good predictive value. Its accuracy was 86.3%.Conclusions: The results of this study indicate that the serum IL-21 could be promising marker in the diagnosis of alopecia areata, and also can be used as prognostic marker of its activity

Temperature dependence growth of CdO thin film prepared by spray pyrolysis

AbstractCdO thin films prepared by spray pyrolysis technique show temperature dependence growth when the spray time is constant. In contrast, the growth is film thickness dependent when the substrate temperature is constant. The films are polycrystalline in the covered spray time and substrate temperature ranges. The crystallite size and microstrain are calculated and analyzed. The Atomic Force Microscopy (AFM) micrographs prove that the grains are uniformly distributed within the scanning areas (5μm×5μm) and (50μm×50μm). The roughness shows a considerable decrease with substrate temperature. All samples show an abrupt change in transmission which indicates a direct transition and good crystallinity. The transmission of films is increased up to 80% with increasing substrate temperature in wavelength ranged from 450nm to 1000nm. Also, a broad absorption band is observed in the range 1500–2000nm. This band could be attributed to the increase in free carrier concentration which confirmed by a reasonable decrease in the film sheet resistance. The band gap Eg is determined and found to be in the range 2.45–2.55eV. The sheet resistance is reduced with increasing deposition temperature due to the increase in free carrier concentration and found to be 66Ω/□ at 450°C

Open Reduction and Internal Fixation with a Small T-plate for Volar Barton Fracture Management

Background: One-sixth of all fractures in the emergency room are distal radius fractures. It is very important to recognize and adequately treat volar Barton fractures to avoid complication of malunion and its adverse effects. Although various fixation techniques have been described, with the plate, the patient can begin early active wrist workouts performing stable reduction. Objective: Open reduction and small T-plate internal fixation of a distal radius volar Barton fracture were used to evaluate the functional outcomes for the fracture treatment. Patients and Methods: At Zagazig University Hospital, 30 patients with a volar Barton fracture were studied in prospective interventional research, the study was carried out through six months. Preoperative X-ray and CT were done and the patient was prepared for surgery. By adopting an FCR technique (flexor carpi radialis approach), the fracture was reduced, the plate was fixed, and the image intensification was utilized for confirming the results. Results: Mean operative time was 54.1±8.47 and of 30 patients operated upon, 16 patients were discharged one day after operation while the mean time lapse before surgery was 1.3±0.53. The mean time of bone union was 6.5±0.89 weeks (range 5-8 weeks). There was a significant improvement in wrist range of motion in all directions postoperatively. 2 patients (6.7%) had superficial infection, 1 patient (3.3%) had tourniquet paralysis, 1 patient had stiffness (3.3%) and another had mal-united fracture (3.3%). Conclusion: Volar distal buttressing with the Ellis T plate is easy and inexpensive, and it delivers good functional benefits. Simplistic and low-complication procedure provides precise anatomical reduction of the fracture and restoration of the wrist's shape and function

The protective effects of adenosine deaminase inhibitor and ouercetin against hepatocellular carcinoma induced by thioacetamide in male rats via downregulation of iNOS, Ki67 and Pan-CK

The liver is the largest and most vulnerable organ in the body, several factors can cause liver cirrhosis and the onset of hepatocellular carcinoma. This study aims to investigate the possibility for adenosine deaminase inhibitor (EHNA) which reduces liver injury, neutrophil infiltration and the levels of proinflammatory cytokines and also it is considering as a target of liver cirrhosis and beginning of hepatocellular carcinoma protective, quercetin which is one of the most common flavonoids has an antioxidant, antitumor and chemopreventive effect on the liver-induced preneoplastic lesions and their combination against thioacetamide as a hepatotoxic and a carcinogenic compound. Biochemical, histopathological and immunohistochemical studies were carried out on male albino rats model to evaluate this possibility. Thioacetamide-treated rats showed a significant increase in liver function tests, alpha-fetoprotein level, expression of inducible Nitric Oxide Synthesis (iNOS), Ki67 and Pan-Cytokeratin (Pan-CK) in hepatic tissue of rats. The results of the present study show that treatment with quercetin, EHNA or their combination attenuated changes in liver functions, histopathological changes, reduced collagen deposition and decreased the expression of iNOS, Ki67 and Pan-CK induced by thioacetamide

Novel heterocyclic derivatives of pyrano[3,2-c]quinolinone from 3-(1-ethy1-4-hydroxy-2-oxo-2(1H)-quinolin-3-yl)-3-oxopropanoic acid

3-(1-Ethyl-4-hydroxy-2-oxo-2(1H)-quinolin-3-yl)-3-oxopropanoic acid (2) has been synthesized. The chemical behaviour of β-ketoacid 2 was studied towards condensation reactions with salicylaldelyde, 2-hydroxy-1-naphthaldehyde, 1-phenyl-4-hydroxy-2-oxo-quinoline-3-carboxaldehyde, 2-hydroxy-4-oxo-4H-pyrido[1,2-a]pyrimidine-3-carboxalde-hyde, 2-amino-3-formylchromone and its 8-allyl analog, 3-cyanochromone and its 8-allyl analog. Structures of the newly synthesized products have been deduced from their elemental analysis and spectral data