Chemical Review and Letters

Abstract In this study, the effects of initial pH (5 − 7), temperature (30 − 38 ◦C) and incubation time (12 − 48 h), as well as yeast extract and free linoleic acid concentrations, respectively (0 – 4 %) and (0 − 400 µL), on the co-production of conjugated linoleic acid (CLA), exopolysaccharides (EPSs) and bacteriocins (BACs) by Lactobacillus acidophilus LA5 and Bifidobacterium animalis subsp. lactis BB12 and their biomass in cheese whey and milk permeate were evaluated. The results showed that biomass, CLA, EPSs and BACs activity ranged Log 0.80 - Log 8.67 g.L-1, 3.08-107.95 µg.mL-1, 107.75-351.92 mg.L-1 and 9.29-14.62 mm, respectively. Yeast extract concentration was the only factor with the positive significant effect on biomass and parabiotic metabolites i.e. its increasing caused to an increase in both of them (p <0.05). The temperature significantly affected the production of biomass and CLA; its increasing resulted in increasing both (p <0.05). The initial pH had significant, but different, effects on EPSs and BACs production (p <0.05) i.e. EPSs and BACs production decreased and increased, respectively, as a result of increased initial pH. Increasing free linoleic acid concentration from 0 up to 400 µL led to increased CLA biosynthesis. Higher biomass, EPSs and BACs are produced in cheese whey, compared with milk permeate, but CLA produced in milk permeate was higher than that obtained in cheese whey. B. animalis BB12 produced more biomass, CLA and EPSs in comparison to L. acidophilus LA5. However, these probiotics had no statistical difference in terms of producing BACs. This work successfully demonstrated the co-production potential of CLA, EPSs and BACs by two commercial probiotics in dairy effluents.

Abstract Two Hf–poorest versions of a high performance chromia–forming nickel–based polycrystalline cast alloy reinforced by HfC carbides were investigated by replacing more or less hafnium by tantalum to reduce production cost. After elaboration, microstructure control, thermal analysis and exposures at temperature were carried out on samples cut in the obtained ingots. The as–cast microstructures of the two alloys are similar to the initial alloy one but their behaviors at the three considered high temperatures (1100, 1200 and 1250°C) were more or less different: more fragmentation of he MC carbides and precipitation of chromium carbides during aging. Some decreasing effects on the room temperature hardness were observed, and one can suppose that the high temperature mechanical properties of these two {(Hf,Ta)C carbides}–containing alloys derived from the HfC–strengthened initial one may be lowered.

Abstract In this study some mechanical properties of PVC-Wood fibre composite were investigated. The wood fibre was gotten from a mahogany tree. The sample was moulded and shaped at a temperature of 150oC using a hadraulic hot press and pressure of 3bar for 5mins and the mechanical properties were studied base on varying the wood fibre contents from 0% to 50%. The hardness test carried out using the durometer hardness tester show a decrease in the hardness of the composite as the wood fibre is varied from 0%, 10%, 20%, 30% 40% and 50% and the impact strength of the composite decreases as well in that order. The tensile strength conducted using the Mensato Tensometer show a decrease at 10% wood fibre, while an increase in the wood fibre to 20% show an increase in the tensile strength on further addition of the wood fibre a decrease is noticed. This decrease in tensile strength decreases the strain of the PVC-wood fibre composite and hence increasing the modulus of elasticity of the PVC-wood fibre composite as the wood fibre is been added.

Abstract This article presents a mini-review of the literature on the laboratory scale pyrolysis of selected plastic waste. Among the various types of polymer materials polyolefins (PE and PP), as well as polystyrene (PS), polyoxymethylene (POM), and polyvinyl chloride (PVC), were selected. The paper highlights valuable compounds and chemical raw materials can be obtained by pyrolyzing the waste polymers.

Abstract In this work, environmentally friendly and cheap method for the synthesis of CdS nanoparticles for the first time using extract of Dicliptera Roxburghiana is presented. The present method is found to be reproducible and rapid. Structural analysis is carried out by UV-visible, FTIR, XRD, EDX, SEM, and TEM. XRD and TEM analysis revealed that the nanoparticles have spherical shape and size in the range of 2.5-8nm. FTIR studies showed the presence of functional groups which belong to the phytochemicals of plant extract that surrounds the nanoparticle preventing them from agglomeration. Thus the prepared CdS NPs exhibit excellent stability even after 2 months. The optical band gap was calculated using Tauc Plot i.e. 3.31 eV. Their activity as photocatalysts against an aqueous solution of methylene blue degradation under solar irradiation in a comparative manner is also reported and the particle has a % degradation of 87.12% in just 120 minutes under solar light irradiation.

Abstract In this study, we developed a QSAR model for studying the antiviral activity of 1,3,4-trisubstituted pyrazoles derivatives on hepatitis C virus infected in human HuH-7 cell lines. We employed random analysis to split the data sets. Statistically robust model was generated with R2, Q2 and R2pred values of 0.777, 0.731 and 0.774 respectively. The reliability of this model was confirmed by acceptable validation parameters, and this model also fulfilled the Golbraikh and Tropsha standard model conditions. Through the evaluation of selected molecular descriptors we observed that, topological charge index of order 4 (GGI4), mean topological charge index of order 1 (JGI1), octanol water partition coefficient (XlogP), 3D topological distance based autocorrelation lag5/weighted by polarizabilities (TDB5p) and total molecular surface area (FPSA-2) are the molecular properties determining biological activities of the study compounds, which shed light on the vital features that aid in the design of unique potent hepatitis C virus entry inhibitors using computer-aided drug design tools.

Abstract In this work, we have successfully incorporated ginger particles into the sodium montmorillonite (Na+-MMT) structure. A new nanoparticles (G-MMT) were characterized using Fourier transform infrared (FT-IR) spectroscopy, ultraviolet-visible-near infrared (UV-VIS-NIR), X-ray diffraction analysis (XRD), energy-dispersive X-ray spectroscopy (EDS), transmission electron microscopy (TEM), scanning electron microscopy (SEM), and thermogravimetric analysis (TGA). Also, the antimicrobial properties of G-MMT nanoparticles were investigated using agar diffusion method. The results showed that the spherical particles of ginger were placed between the layers, and also slightly on the surface. Montmorillonite (MMT) layers, such as heat shields, protect the ginger from degradation. The results of antibacterial test showed that G-MMT inhibits 8 lethal types of gram-positive and gram-negative bacteria, as well as one type of yeast. Due to the antibacterial properties of G-MMT and the fact that ginger is protected at high temperatures, this nanoparticle can have a suitable place in various applications.