Synthesis and biological evaluation of certain new thiazolopyrimidines

A series of 5-methyl-3-phenyl thiazolo[5,4-e][1,2,4]triazolo[1,5-c] pyrimidin-2-thiones and 5-methyl-3-phenyl thiazolo[5,4-e]pyrimidino[3,4-b][1,2,4]triazin-2-thiones were prepared as potential antimicrobial and antitumor agents. Some of the tested compounds showed promising activity. The detailed synthesis, spectroscopic and biological data are reported.     

The effect of heparin hydrogel embedding on glutaraldehyde fixed bovine pericardial tissues: Mechanical behavior and anticalcification potential

Heart valve diseases remain common in industrialized countries. Bioprosthetic heart valves, introduced as free of anticoagulation therapy alternatives to mechanical substitutes. Still they suffer from long term failure due to calcification. Different treatment methods introduced to inhibit calcification, have so far been limited in success. Glycosaminoglycans (GAGs) possess properties including high negative charge, anticoagulation and anti-inflammatory activity that make them a potential solution for calcification problem. In this study, heparin hydrogel was prepared and characterized both chemically and mechanically. After that, heparin hydrogel embedded bovine pericardial tissues, fixed with glutaraldehyde, were produced and tested for their mechanical behavior and anticalcifcation potential in vitro using the constant composition model. In the calcification experiments, tissues were divided into three groups: a) Controls without treatment, b) Hydrogel treated tissues and c) Tissues with raw heparin dissolved in the calcification solution. The results showed that embedding of tissue with hydrogel had no stiffening effect on its mechanical behavior. Calcification assessment showed a significant efficacy on inhibition of calcium phosphate deposition of hydrogel treated (second group) in comparison to untreated tissues (control, first group). Calcification inhibition potential was very similar in both the second and raw heparin (third group). Histological data confirmed the obtained results, suggesting that heparin treatment is a promising anticalcification agent.

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Growth temperature impact on MOVPE-grown BInGaAs/GaAs QWs designed for optoelectronic applications

Journal of Materials Science: Materials in Electronics - In this work, quaternary BInGaAs single quantum wells have been grown on GaAs substrate by metal–organic vapor-phase epitaxy. The...     

Nitrosamine formation from different Catha edulis leaves extracts under simulated gastric condition

Nitrosamines are well-known carcinogenic and toxic compounds for humans and animals. The aim of this study was to investigate the possible formation of nitrosamine compounds from aqueous extracts of five different types of Catha edulis leaves using nitrite as a nitrosation agent, either in aqueous solution or under simulated normal fasting stomach conditions (at 37 °C and pH 2) for 1 h. Nitrosoephedrine was used as a reference compound in this study. Nitrosation of aqueous extracts of the different types of Catha edulis leaves with constant concentration of nitrite (14.4 mM) in aqueous solution showed total apparent nitrosamine compounds to be in the range 94–319 mg/100 g DM (dry matter) of CE (Catha edulis) leaves. In contrast, nitrosamines formed in simulated gastric fluid were much lower, in the range 23–79 mg/100 g DM of CE leaves. Based on the moderate formation of nitrosamines with the Sabri Catha edulis leaves, the latter was selected for investigating the effect of varying levels of nitrite in aqueous solution and simulated gastric juice. The nitrosation of aqueous extracts of Sabri Catha edulis with different levels of nitrite in aqueous solution yielded a dose-dependent amount of total apparent nitrosamine compounds, these being undetected at ?0.5 mM sodium nitrite in aqueous solution and ?1 mM in simulated gastric juice. This raises the question of whether the observed high incidence of esophageal and forestomach carcinomas in Yemen could be attributed to the formation of nitrosamines in vivo from the secondary amines present in Catha edulis leaves.     

A significant improvement in adsorption behavior of mesoporous TUD-1 silica through neodymium incorporation

Neodymium was incorporated into the three-dimensional mesoporous siliceous material TUD-1.In order to understand the chemical and morphological structure of the prepared material,several characterization techniques were performed.The characterization results show the formation of highly distributed isolated Nd3+ions incorporated in the silica matrix in tetrahedrally coordinated structure,moreover no aggregation of separate phase(s)was/were observed.The prepared material was investigated as an adsorbent for methyl green(MG)dye in aqueous solution as a model cationic dye.The results show higher adsorption capacity for Nd-TUD-1 by almost 24 times higher than the neat parent TUD-1 material and more than 100 times higher than bulky Nd₂O₃under neutral pH.The adsorption results were fitted perfectly with pseudo-second-order model.Moreover,the adsorption isotherms were perfectly fitted with Freundlich isotherm model which indicates the formation of a multilayer of the dye molecules onto the Nd-TUD-1 surface as a physisorption with endothermic nature.     

Artificial Intelligence Based Sentiment Analysis for Health Crisis Management in Smart Cities

Smart city promotes the unification of conventional urban infrastructure and information technology (IT) to improve the quality of living and sustainable urban services in the city. To accomplish this, smart cities necessitate collaboration among the public as well as private sectors to install IT platforms to collect and examine massive quantities of data. At the same time, it is essential to design effective artificial intelligence (AI) based tools to handle healthcare crisis situations in smart cities. To offer proficient services to people during healthcare crisis time, the authorities need to look closer towards them. Sentiment analysis (SA) in social networking can provide valuable information regarding public opinion towards government actions. With this motivation, this paper presents a new AI based SA tool for healthcare crisis management (AISA-HCM) in smart cities. The AISA-HCM technique aims to determine the emotions of the people during the healthcare crisis time, such as COVID-19. The proposed AISA-HCM technique involves distinct operations such as pre-processing, feature extraction, and classification. Besides, brain storm optimization (BSO) with deep belief network (DBN), called BSO-DBN model is employed for feature extraction. Moreover, beetle antenna search with extreme learning machine (BAS-ELM) method was utilized for classifying the sentiments as to various classes. The use of BSO and BAS algorithms helps to effectively modify the parameters involved in the DBN and ELM models respectively. The performance validation of the AISA-HCM technique takes place using Twitter data and the outcomes are examined with respect to various measures. The experimental outcomes highlighted the enhanced performance of the AISA-HCM technique over the recent state of art SA approaches with the maximum precision of 0.89, recall of 0.88, F-measure of 0.89, and accuracy of 0.94.