Exploration of the effects of Coriolis force and thermal radiation on water-based hybrid nanofluid flow over an exponentially stretching plate.

Hybrid nanofluids' enhanced thermophysical properties make them applicable in a plethora of mechanical and engineering applications requiring augmented heat transfer. The present study focuses on a three-dimensional Copper-Aluminium Oxide [Formula: see text]-water based hybrid nanofluid flow within the boundary layer with heat transfer over a rotating exponentially stretching plate, subjected to an inclined magnetic field. The sheet rotates at an angular velocity [Formula: see text] and the angle of inclination of the magnetic field is [Formula: see text]. Employing a set of appropriate similarity transformation reduces the governing PDEs to ODEs. The resulting ODEs are solved with the finite difference code with Shooting Technique. Primary velocity increases at large rotation but the secondary velocity reduces as the rotation increases. In addition, the magnetic field is found to oppose the flow and thereby causing a reduction in both the primary and secondary velocities. Increasing the volume fraction reduces the skin friction coefficient and enhances the heat transfer rate.

Prevalence of hepatitis B virus infection and uptake of hepatitis B vaccine among healthcare workers, Makueni County, Kenya 2017.

BACKGROUND: Hepatitis B virus (HBV) is a vaccine-preventable infection that can spread in healthcare setting. Data on HBV infections and vaccine in African healthcare workers (HCWs) are limited. We estimated HBV infection prevalence, hepatitis B vaccination status and identified factors associated with vaccination in one Kenyan county. METHODS: Randomly selected HCWs completed a questionnaire about HBV exposure and self-reported immunization histories, and provided blood for testing of selected HBV biomarkers to assess HBV infection and vaccination status: HBV core antibodies (anti-HBc), HBV surface antigen (HBsAg) and HBV surface antibodies (anti-HBs). Prevalence odds ratios (OR) with 95% confidence intervals (95% CI) were calculated to identify factors associated with vaccination. RESULTS: Among 312 HCWs surveyed, median age was 31 years (range: 19-67 years). Of 295 blood samples tested, 13 (4%) were anti-HBc and HBsAg-positive evidencing chronic HBV infection; 139 (47%) had protective anti-HBs levels. Although 249 (80%) HCWs received ≥1 HBV vaccine dose, only 119 (48%) received all three recommended doses. Complete vaccination was more likely among those working in hospitals compared to those working in primary healthcare facilities (OR = 2.5; 95% CI: 1.4-4.3). CONCLUSION: We recommend strengthening county HCW vaccination, and collecting similar data nationally to guide HBV prevention and control.

Antimicrobial Coumarins from the Oyster Culinary-Medicinal Mushroom, Pleurotus ostreatus (Agaricomycetes), from Kenya.

Pleurotus ostreatus has been widely used as food because of its nutritional and medicinal properties. These have been attributed to the presence of macronutrients, minerals, vitamins, and amino acids, among other secondary metabolites. There are, however, few reports on the antimicrobial activities of different classes of purified compounds from P. ostreatus. This led to the current study, the objective of which was to chemically characterize the antibiotic activities of P. ostreatus against selected human pathogenic bacteria and endophytic fungi. Chemical structures were determined using spectroscopic methods and by comparison with values of related structures reported in the literature. Pure compounds from P. ostreatus were tested in vitro against pathogenic bacteria (Staphylococcus aureus and Escherichia coli) and endophytic fungi (Pencillium digitatum and Fusarium proliferatum). A new compound, (E)-5,7-dimethoxy-6-(3-methylbuta-1,3-dienyl)-2H-chromen-2-one (5-methoxy-(E)-suberodiene) (compound 2), along with ergosterol (compound 1) and 5,7-dimethoxy-6-(3-methylbut-2-enyl)-2H-chromen-2-one (toddaculin; compound 3), were isolated from the fruiting bodies of P. ostreatus. The growth of S. aureus, F. proliferatum, and P. digitatum colonies was inhibited in media containing compound 2, with minimum inhibitory concentrations closely comparable to those of conventional antibiotics.

Flavones and phenylpropenoids in the surface exudate of Psiadia punctulata.

Three flavones, 5,7-dihydroxy-2',3',4',5'-tetramethoxyflavone, 5,4'-dihydroxy-7,2',3',5'-tetramethoxyflavone, and 5,7,4'-trihydroxy-2',3',5'-trimethoxyflavone were isolated from the leaf exudate of Psiadia punctulata, together with the previously reported 5-hydroxy-7,2',3',4',5'-pentamethoxyflavone and 5,7,3'-trihydroxy-2',4',5'-trimethoxyflavone. The two phenylpropenoids, Z-docosyl-p-coumarate and E-docosyl-p-coumarate were also isolated. The structures were determined on the basis of spectroscopic evidence.

Curcumin blocks cytokine-mediated NF-kappa B activation and proinflammatory gene expression by inhibiting inhibitory factor I-kappa B kinase activity.

NF-kappa B plays a critical role in the transcriptional regulation of proinflammatory gene expression in various cells. Cytokine-mediated activation of NF-kappa B requires activation of various kinases, which ultimately leads to the phosphorylation and degradation of I kappa B, the NF-kappa B cytoplasmic inhibitor. The food derivative curcumin has been shown to inhibit NF-kappa B activity in some cell types. In this report we investigate the mechanism of action of curcumin on cytokine-induced proinflammatory gene expression using intestinal epithelial cells (IEC). Curcumin inhibited IL-1 beta-mediated ICAM-1 and IL-8 gene expression in IEC-6, HT-29, and Caco-2 cells. Cytokine-induced NF-kappa B DNA binding activity, RelA nuclear translocation, I kappa B alpha degradation, I kappa B serine 32 phosphorylation, and I kappa B kinase (IKK) activity were blocked by curcumin treatment. Wound-induced p38 phosphorylation was not inhibited by curcumin treatment. In addition, mitogen-activated protein kinase/ERK kinase kinase-1-induced IL-8 gene expression and 12-O-tetraphorbol 12-myristate 13-acetate-responsive element-driven luciferase expression were inhibited by curcumin. However, I kappa B alpha degradation induced by ectopically expressed NF-kappa B-inducing kinase or IKK was not inhibited by curcumin treatment. Therefore, curcumin blocks a signal upstream of NF-kappa B-inducing kinase and IKK. We conclude that curcumin potently inhibits cytokine-mediated NF-kappa B activation by blocking a signal leading to IKK activity.

Three-dimensional quantitative structure--activity relationships for androgen receptor ligands.

Comparative molecular field analysis (CoMFA), a three-dimensional quantitative structure-activity relationship (3D-QSAR) paradigm, was used to examine androgen receptor-binding affinities of a series of structurally diverse natural, synthetic, and environmental chemicals of interest. The CoMFA/3D-QSAR model successfully illustrates that the overall steric and electrostatic properties of structurally diverse ligands for the androgen receptor are necessary and sufficient to describe the binding affinity. The practical utility of models of this type is demonstrated using parent compounds in the training set and known as well as putative biological metabolites as test set molecules. The ability of the model to accurately predict binding affinity of test set molecules suggests that structure-based 3D-QSAR models may be used to supplement the process of hazard identification. The application of 3D-QSAR models within a toxicological framework is, at present, limited by the quantity and quality of biological data for relevant biomarkers of toxicity.

A bimetallic hydroformylation catalyst: high regioselectivity and reactivity through homobimetallic cooperativity.

The racemic and meso diastereomers of an electron-rich binucleating tetraphosphine ligand have been used to prepare homobimetallic rhodium norbornadiene complexes. The racemic bimetallic Rh complex is an excellent hydroformylation catalyst for 1-alkenes, giving both a high rate of reaction and high regioselectivity for linear aldehydes, whereas the meso complex is considerably slower and less selective. A mechanism involving bimetallic cooperativity between the two rhodium centers in the form of an intramolecular hydride transfer is proposed. Mono- and bimetallic model complexes in which the possibility for bimetallic cooperativity has been reduced or eliminated are very poor catalysts.