Performance Studies of Natural Rubber/Organomodified Kaolin Vulcanizates Developed for Tire Sidewall Applications

This study aims at evaluating the performance of Natural Rubber/organomodified kaolin vulcanizates to ascertain its suitability for tire sidewall applications. The cure characteristics, filler dispersion, tensile and tear properties and De-Mattia flex fatigue characteristics of natural rubber (NR) filled with 2-10 phr of Rubber Seed Oil (RSO), and Tea Seed Oil (TSO) modified kaolin developed specifically for tire sidewall applications were assessed. The NR compounds containing RSO and TSO modified kaolin showed lower optimum cure time (t90 at 150°C) as against that containing the same dosage of unmodified kaolin. The results show significant increases in tensile modulus, tensile strength and tear strength for the NR vulcanizates containing the organomodified kaolins, compared to vulcanizates containing unmodified kaolin. TSO modified kaolin vulcanizates at 6phr showed better resistance to crack initiation and flex fatigue failure. The SEM and AFM micrographs of the vulcanizates containing organomodified kaolins also showed an excellent uniform dispersion of the filler particles in the NR matrix. The results obtained for Natural Rubber/Tea Seed Oil modified kaolin vulcanizates at 10phr shows a short optimum cure time, high maximum torque, better tear strength, excellent resistance to crack initiation and flex fatigue behaviour. These indicate that the Natural Rubber/Tea Seed Oil modified kaolin vulcanizates are preferred materials for tire sidewall applications

Statistical prediction of the drying behavior of blanched ginger rhizomes

ARS-680 environmental chamber was employed in this study to determine the drying behavior of sliced ginger rhizomes. Blanched and unblanched treated ginger rhizomes were considered at drying temperature of 40 °C for a period of 2 – 24 h. Linear and non-linear regression analyses were employed to establish the correlation that exits between the drying time and the moisture ratio. Correlation analysis, root mean square error (RMSE) and standard error of estimate (SEE) analysis were chosen in selecting the best thin layer drying models. Higher values of determination coefficient (R2) show goodness of fit and lower values of SEE implies better correlation; and RMSE values were also utilized in determining the goodness of fit. The drying data of the variously treated ginger samples were fitted into the twelve thin layer drying models and the data obtained were fitted by multiple non-linear regression technique. Blanched treated sample exhibited a better drying behavior losing about 82.87 % moisture content compared with unbleached sample that lost about 62.03 % of moisture content. Two-term exponential drying model proved to be the most suitable model for predicting the drying behavior of ginger rhizome. The model exhibited high R2 values of 0.9349-0.9792 (which are close to unity) for both blanched and unbleached samples. Also, it recorded relatively low values of RMSE and SEE (3.6865 - 2.0896 and 3.6564-2.7486 respectively) for both treatments. &nbsp

Bacteria Associated with Domestic Solid Waste Dump in Egbu, Owerri North Local Government Area in Imo State, Nigeria.

The prevalence of bacteria in solid waste dump from domestic waste in Owerri was studied. Six samples were collected from Egbu community in Owerri North and examined bacteriologically using Nutrient agar and macconkey agar and were serially diluted, cultured, identified and characterized. Five genera of bacteria were isolated. They were Staphylococcus aureus, Klebsiella sp, Escherichia coli, lactobacillus sp and Corynebacterium sp and from the findings,Klebsiella exhibited the highest  number of bacterial activity (66.6%) while Corynebacterium and Iactobacillus exhibited the lowest number of bacterial activity (16.67%). Futhermore, location D had the highest total heterotropic bacterial count of 5.75x 108 and the least was location E with 6.25x107. The presence of Escherichia coli, Staphylococcus aureus, Cornebacteria and Klebsiella in the waste dump site is an indication that the contamination is of human and plant orign or their activities. Keywords: Nutrient agar ,macconkey agar , Staphylococcus aurous, Klebsiellasp, Escherichia coli,  Lactobacillus sp and Corynebacterium sp.

TLR2/MyD88/NF-κB Pathway, Reactive Oxygen Species, Potassium Efflux Activates NLRP3/ASC Inflammasome during Respiratory Syncytial Virus Infection

Human respiratory syncytial virus (RSV) constitute highly pathogenic virus that cause severe respiratory diseases in newborn, children, elderly and immuno-compromised individuals. Airway inflammation is a critical regulator of disease outcome in RSV infected hosts. Although “controlled” inflammation is required for virus clearance, aberrant and exaggerated inflammation during RSV infection results in development of inflammatory diseases like pneumonia and bronchiolitis. Interleukin-1β (IL-1β) plays an important role in inflammation by orchestrating the pro-inflammatory response. IL-1β is synthesized as an immature pro-IL-1β form. It is cleaved by activated caspase-1 to yield mature IL-1β that is secreted extracellularly. Activation of caspase-1 is mediated by a multi-protein complex known as the inflammasome. Although RSV infection results in IL-1β release, the mechanism is unknown. Here in, we have characterized the mechanism of IL-1β secretion following RSV infection. Our study revealed that NLRP3/ASC inflammasome activation is crucial for IL-1β production during RSV infection. Further studies illustrated that prior to inflammasome formation; the “first signal” constitutes activation of toll-like receptor-2 (TLR2)/MyD88/NF-κB pathway. TLR2/MyD88/NF-κB signaling is required for pro-IL-1β and NLRP3 gene expression during RSV infection. Following expression of these genes, two “second signals” are essential for triggering inflammasome activation. Intracellular reactive oxygen species (ROS) and potassium (K+) efflux due to stimulation of ATP-sensitive ion channel promote inflammasome activation following RSV infection. Thus, our studies have underscored the requirement of TLR2/MyD88/NF-κB pathway (first signal) and ROS/potassium efflux (second signal) for NLRP3/ASC inflammasome formation, leading to caspase-1 activation and subsequent IL-1β release during RSV infection

Thermal and mechanical properties of modified CaCO3 filled poly (ethylene terephthalate) nanocomposites

Poly(ethylene terephthalate) (PET)/CaCO3 and PET/modified-CaCO3 (m-CaCO3) nanocomposites were prepared by melt blending. The morphology indicated that m-CaCO3 produced by reacting sodium oxalate and calcium chloride, was well dispersed in PET matrix and showed good interfacial interaction with PET compared to CaCO3. No significant differences in the thermal properties such as, glass transition, melting and degradation temperatures, of the nanocomposites were observed. The thermal shrinkage of PET at 120 ??C was 10.8 %, while those of PET/CaCO3 and PET/m-CaCO3 nanocomposites were 2.9-5.2 % and 1.2-2.8 %, respectively depending on filler content. The tensile strength of PET/CaCO3 nanocomposite decreased with CaCO3 loading, whereas that of PET/m-CaCO3 nanocomposites at 0.5 wt% loading showed a 17 % improvement as compared to neat PET. The storage modulus at 120 ??C increased from 1660 MPa for PET to 2350 MPa for PET/CaCO3 nanocomposite at 3 wt% loading, and 3230 MPa for PET/m-CaCO3 nanocomposite at 1 wt% loadinclose0

Reactive oxygen and nitrogen species during viral infections

Abstract Oxygen and nitrogen radicals are frequently produced during viral infections. These radicals are not only a physiological mechanism for pathogen clearance but also result in many pathological consequences. Low concentrations of radicals can promote viral replication; however high concentrations of radicals can also inhibit viral replication and are detrimental to the cell due to their mitogenic activity. We reviewed the detailed mechanisms behind oxygen and nitrogen radical production and focused on how viruses induce radical production. In addition, we examined the effects of oxygen and nitrogen radicals on both the virus and host. We also reviewed enzymatic and chemical detoxification mechanisms and recent advances in therapeutic antioxidant applications. Many molecules that modulate the redox balance have yielded promising results in cell and animal models of infection. This encourages their use in clinical practice either alone or with existing therapies. However, since the redox balance also plays an important role in host defence against pathogens, carefully designed clinical trials are needed to assess the therapeutic benefits and secondary effects of these molecules and whether these effects differ between different types of viral infections