A new lanostane-type triterpene and sesquiterpene lactones from Vernonia leopoldii and their in vitro cytotoxicity

Investigation of the aerial parts of Vernonia leopoldii (Sch. Bip.) Vatke afforded a new lanostane-type triterpene along with known hirsutinolide-type sesquiterpene lactones and flavonoid glycosides, all are identified for the first time in this species. The new compound was identified as lanost-3β, 23S-dihydroxy-22(31)-ene. The structures of the isolated compounds were elucidated based on spectroscopic evidence. The hirsutinolides and the triterpene were evaluated for their cytotoxicity against four human cancer cell lines using MTT assay.     

Click Chemistry Based Synthesis of Novel Architectures Bearing Sugar Unit at the Pyridothienopyrimidines

Novel conjugates of pyridothienopyrimidinones and carbohydrates or other moieties linked by 1,2,3‐triazoles were synthesized. After establishing the pyridothienopyrimidone ring systems by ring closure, propargyl group was introduced by O‐alkylation or N‐alkylation. Cu‐catalyzed cycloaddition of the propargyl product with azido group gave the corresponding 1,2,3‐triazoles in high yields. A remarkable case of the catalyzed ring closure to build a pyrimidinone moiety with two diastereomers was observed. Theoretical calculations were performed on the studied diastereomers, and it was found that the S‐isomer is more stable than the corresponding R‐isomer by about 2 kcal/mol.     

Regioselective Synthesis of Some New Pyrazolo[1,5‐a]pyrimidines,Pyrazolo[1,5‐a]quinazoline and Pyrimido[4′,5′:3,4]pyrazolo[1,5‐a] pyrimidines Containing Thiazole Moiety

A regioselective synthesis of novel pyrazolo[1,5‐a]pyrimidines, pyrazolo[1,5‐a]quinazoline and pyrimido[4′,5′:3,4]pyrazolo[1,5‐a]pyrimidines incorporating a thiazole moiety was described via the reactions of the versatile, readily accessible 5‐amino‐3‐(phenylamino)‐N‐(4‐phenylthiazol‐2‐yl)‐1H‐pyrazole‐4‐carboxamide 3 with appropriate 1,3‐biselectrophilic reagents namely, β‐diketones, enaminones, and α,β‐unsaturated cyclic ketone. The newly synthesized compounds were elucidated by elemental analysis, spectral data, and alternative synthetic route whenever possible.     

Temperature dependent viscosity and thermal conductivity effects on combined heat and mass transfer in MHD three-dimensional flow over a stretching surface with Ohmic heating

An analysis has been carried out to obtain the flow, heat and mass transfer characteristics of a viscous electrically conducting fluid having temperature dependent viscosity and thermal conductivity past a continuously stretching surface, taking into account the effect of Ohmic heating. The flow is subjected to a uniform transverse magnetic field normal to the plate. The resulting governing three-dimensional equations are transformed using suitable three-dimensional transformations and then solved numerically by using fifth order Runge–Kutta–Fehlberg scheme with a modified version of the Newton–Raphson shooting method. Favorable comparisons with previously published work are obtained. The effects of the various parameters such as magnetic parameter M, the viscosity/temperature parameter θ _r , the thermal conductivity parameter S and the Eckert number Ec on the velocity, temperature, and concentration profiles, as well as the local skin-friction coefficient, local Nusselt number, and the local Sherwood number are presented graphically and in tabulated form.     

On Multiobjective Oligopoly

Multiobjective oligopoly models are constructed. The objectives of the first two models are to maximize profits and to maximize sales. In the third model the objectives are to maximize profits and to minimize risk. Giving more weight to risk minimization decreased the profits. In all three models, we found that the weight of profit maximization has to be higher than a given threshold. Again they require that the weight of profit maximization has to be higher than a certain value.     

Antimicrobial activity of new carboxymethyl chitosan–carbon nanotube biocomposites and their swell ability in different pH media

New carboxymethyl chitosan–carbon nanotube (CMCS-CNT) biocomposites were prepared and characterized by Fourier transform infrared spectroscopy, transmission electron microscopy, scanning electron microscopy, X-ray diffraction, and normal photography. The recorded images of the CMCS-CNT biocomposites showed homogeneous distribution of carbon nanotubes into the carboxymethyl chitosan (CMCS) matrix. Their antimicrobial activity and swell ability in different pH media have been investigated. They showed a higher antimicrobial activity against tested gram-positive and gram-negative bacteria. The inhibition zone diameters are closer to that recorded for the commonly used antibiotics. They showed an increase in the swell ability in different pH media relative to the parent CMCS. It would be expected that these nanobiocomposites are promising candidates for medical applications.     

Development of porous,antibacterial and biocompatible GO/n-HAp/bacterial cellulose/β-glucan biocomposite scaffold for bone tissue engineering

Due to their potential renewable materials-based tissue engineering scaffolds has gained more attention. Therefore, researchers are looking for new materials to be used as a scaffold. In this study, we have focused on the development of a nanocomposite scaffold for bone tissue engineering (using bacterial cellulose (BC) and β-glucan (β-G)) via free radical polymerization and freeze-drying technique. Hydroxyapatite nanoparticles (n-HAp) and graphene oxide (GO) were added as reinforcement materials. The structural changes, surface morphology, porosity, and mechanical properties were investigated through spectroscopic and analytical techniques like Fourier transformation infrared (FT-IR), scanning electron microscope (SEM), Brunauer–Emmett-Teller (BET), and universal testing machine Instron. The scaffolds showed remarkable stability, aqueous degradation, spongy morphology, porosity, and mechanical properties. Antibacterial activities were performed against gram -ive and gram + ive bacterial strains. The BgC-1.4 scaffold was found more antibacterial compared to BgC-1.3, BgC-1.2, and BgC-1.1. The cell culture and cytotoxicity were evaluated using the MC3T3-E1 cell line. More cell growth was observed onto BgC-1.4 due to its uniform interrelated pores distribution, surface roughness, better mechanical properties, considerable biochemical affinity towards cell adhesion, proliferation, and biocompatibility. These nanocomposite scaffolds can be potential biomaterials for fractured bones in orthopedic tissue engineering.     

Ionic liquids in enhancing the sensitivity of capillary electrophoresis: Off‐line and on‐line sample preconcentration techniques

The popularity of ionic liquids (ILs) has grown during the last decade in enhancing the sensitivity of CE through different off‐line or on‐line sample preconcentration techniques. Water‐insoluble ILs were commonly used in IL‐based liquid phase microextraction, in all its variants, as off‐line sample preconcentration techniques combined with CE. Water‐soluble ILs were rarely used in IL‐based aqueous two phase system (IL‐ATPS) as an off‐line sample preconcentration approach combined with CE in spite of IL‐ATPS predicted features such as more compatibility with CE sample injection due to its relatively low viscosity and more compatibility with CE running buffers avoid, in some cases, anion exchange precipitation. Therefore, the attentions for the key parameters affecting the performance of IL‐ATPSs were generally presented and discussed. On‐line CE preconcentration techniques containing IL‐based surfactants at nonmicellar or micellar concentrations have become another interesting area to improve CE sensitivity and it is likely to remain a focus of the field in the endeavor because of their numerous to create rapid, simple and sensitive systems. In this article, significant contributions of ILs in enhancing the sensitivity of CE are described, and a specific overview of the relevant examples of their applications is also given.     

Antioxidant activities and liquid chromatography with electrospray ionization tandem mass spectrometry characterization and quantification of the polyphenolic contents of Rumex nervosus Vahl leaves and stems

In the present study, four compounds, viz. chlorogenic acid, catechin, orientin, and apigenin‐O‐acetylglycoside among 18 polyphenol compounds (17 flavonoids and one hydroxycinnamic acid derivative) were characterized for the first time in Rumex nervosus leaves and stems by using liquid chromatography with electrospray ionization tandem mass spectrometry. Method validation in terms of determination coefficient, limits of detection, and quantification were ≥ 0.9979, 0.68–1.61, and 2.27–5.38 mg/L, respectively. Accuracy, expressed as percent recovery for two spiking levels (10 and 50 mg/L), were in the range 78.9–110.6% with the exception of caffeic acid. The relative standard deviations were 1–17%. The total polyphenol content was higher by approximately two times in the leaf (1073 mg/kg fresh sample) than in the stem (519.86 mg/kg fresh sample). The antioxidant effects increased in a dose‐dependent manner, and the scavenging activities, investigated by measuring 2,2′‐azino‐bis(3‐ethylbenzothiazoline‐6‐sulfonic acid) scavenging activity, ferrous ions chelating activity, superoxide anion radical scavenging activity, and ferric reducing antioxidant power activity, were significant (p < 0.05) using low concentrations of the leaf extract. Overall, the present study suggests that different parts of R. nervosus have great potential for producing a range of extracts with potential applications in medicine.