Vrănceanu connections and foliations with bundle-like metrics

We show that the Vrănceanu connection which was initially introduced on non-holonomic manifolds can be used to study the geometry of foliated manifolds. We prove that a foliation is totally geodesic with bundle-like metric if and only if this connection is a metric one. We introduce the notion of a foliated Riemannian manifold of constant transversal Vrănceanu curvature and the notion of a transversal Einstein foliated Riemannian manifold. The geometry of these two classes of manifolds is studied and the relationship between them is determined.     

Efficient photocatalytic degradation of Acid Red 57 using synthesized ZnO nanowires

Zinc oxide photocatalyst was synthesized through a low‐temperature co‐precipitation process using zinc sulfate as precursor for the degradation of Acid Red 57 (AR57) under UV irradiation. The activities of the prepared photocatalyst at different calcination temperatures (400, 500, and 600 °C) were investigated. The synthesized zinc oxides were characterized by different techniques such as X‐ray diffraction, scanning electron microscopy, energy‐dispersive X‐ray spectroscopy, N₂ adsorption–desorption, and pH titration for the determination of the zero‐point charge (pH_ZPC). The efficiency of photocatalytic degradation of ZnO prepared at the calcination temperatures of 400, 500, and 600 °C was 90.03, 77.67, and 72.71%, respectively, after 190 min. The kinetics and scavengers of the reactive species during the degradation were also investigated. It was found that the degradation of AR57 fitted first‐order kinetics and the OH^? radicals were the main species. During irradiation, the formation of OH^? free radicals was ascertained by photoluminescence studies using terephthalic acid as the probe molecule.     

Design,synthesis, and characterization of novel pyrimidines bearing indole as antimicrobial agents

Pyrimidines and pyrimidine bearing indole derivatives are very important species in organic chemistry due to their wide use as bioactive compounds with a broad range of good biological activities. Due to the wide spread of different species of bacteria and fungi nowadays, in the present work, a novel series of indolyl‐pyrimidines (2–13) were synthesized starting from 3‐chloro‐1H‐indole‐2‐carbaldehyde (1) . Elemental analysis, IR, 1H‐NMR, 13C‐NMR, and mass spectral data elucidated the structure of newly synthesized compounds. All compounds were screened for their in vitro antibacterial and antifungal activity, and they demonstrated promising results; all the new compounds synthesized from compound (1) , which allowed reactions with thiourea and ethyl cyanoacetate, gave the target compound (2) , which was used as a precursor for the synthesis of indolylthiazolopyrimidine derivatives (3–8) by reactions with halocarbonyl compounds such as chloroacetone, phancyl bromide, and chloroacetic acid through alkylation of the mercapto group followed by cyclization through a nucleophilic attack. When compound (2) subjected to react with hydrazine hydrate gave 4‐indolyl‐2‐hydrazinopyrimidine (5) , the latter compound, when allowed to react with ethyl chloroacetate or diethyloxalate, gave indolylpyrimidotriazine derivatives (10 , 11) ; in contrast, when the compound reacted with acetic anhydride or formic acid, it gave triazolopyrimidine derivatives (12, 13) .     

Preparation of New Multiarmed RAFT Agents for the Mediation of Vinyl Acetate Polymerization

Summary: In this study five xanthate (Reversible Addition-Fragmentation chain Transfer (RAFT)/Macromolecular Design through Interchange of Xanthates (MADIX)) agents were synthesized, namely monofunctional, difunctional, trifunctional and tetrafunctional species of the form SC(O-Z)-S-R, with different leaving groups and different activating moieties some of which are completely novel. Polyvinyl acetates (PVAc) in the form of linear, three armed and four armed star shaped polymers were then successfully synthesized in reactions mediated by these xanthate RAFT/MADIX agents.     

Iron powder and tin/tin chloride as new reducing agents of Meerwein arylation reaction with unexpected recycling to anilines

Abstract

Simple and rapid route for Meerwein arylation reaction using iron powder or a mixture of tin/tin chloride has been developed. In the presence of iron powder, different aryl diazonium salts reacted with methyl vinyl ketone, acrylates, and isopropenyl acetate. Production of oximes was detected as the main product with acrylates or in a mixture with β-aryl methyl ketones in the case of methyl vinyl ketone. The in situ produced HNO₂ from an excess of NaNO₂/HCl was trapped by alkyl aryl radical to form oximes in the E configuration form. The presence of tin/tin chloride mixture in the reaction of the aryl diazonium salts with methyl vinyl ketone produced Michael products along with β-aryl methyl ketones. The predicted α-aryl methyl ketones from the reaction of isopropenyl acetate with the diazotized anilines were obtained using iron or tin/tin chloride mixture.     

A closer look at "social" boundary genes reveals knowledge to gene expression profiles

As social network analysis is gaining popularity in modeling real world problems, the task of applying the social network model concepts and notions to biological data is still one of the most attractive research problems to be addressed. According, our work described in this paper focuses on a particular set of genes that reside on the community boundaries in gene co-expression networks. Stemmed from community mining problem in social networks, peripheries of communities (i.e., boundaries) can be used to aid certain biological analysis. The proposed method consists of three parts: 1) Finding communities of gene co-expression networks through clustering. 2) Analyzing stability of community structures by Monte Carlo method. 3) Designing of dynamic adoption of boundaries using geometric convexity. We validated our findings using breast cancer gene expression data from various studies. Our approach contributes to the new branch of applying social network mechanisms in biological data analysis, leading to new data mining strategies implied by witnessing social behaviors in gene expression analysis.     

Evaluation of the Effect of Elite Jojoba Lines on the Chemical Properties of their Seed Oil

Jojoba oil (JO) extracted from seeds has outstanding properties, including anti-inflammatory, antioxidant, and antibacterial activities, and can be stored forlong periodsof time. The unique properties of jojoba oil depend on its chemical composition; therefore, the effect of the jojoba genotype on the chemical properties and active components of the seed oil was evaluated in this study. Oil samples were collected from 15 elite Egyptian jojoba lines. The chemical composition, such as moisture, crude fiber, crude oil, ash, and crude protein of elite lines’ seeds was determined to investigate the variation among them based on the jojoba genotype. In addition, the iodine value was obtained to measure the degree of jojoba oil unsaturation, whereas the peroxide number was determined as an indicator of the damage level in jojoba oil. Fatty acid composition was studied to compare elite jojoba lines. Fatty acid profiles varied significantly depending on the jojoba genotype. Gadoleic acid exhibited the highest percentage value (67.85–75.50%) in the extracted jojoba oil, followed by erucic acid (12.60–14.81%) and oleic acid (7.86–10.99%). The iodine value, peroxide number, and fatty acid composition of the tested elite jojoba lines were compared withthose reported by the International Jojoba Export Council (IJEC). The results showed that the chemical properties of jojoba oils varied significantly, depending on the jojoba genotype.