Uptake of Nickel(II) Ion by Silica-o-Phenylenediamine Derived from Rice Husk Ash

Silicon - The silica-ortho-phenylenediamine(RHAOPDA) derived from Rice Husk Ash and o- phenylenediamine (OPDA) were synthesized. The prepared material was characterized by different techniques; N2-...     

Physical characterization and performance of iron polymer composites

The physical properties of poly(ethylene oxide) (PEO) composites containing natural iron oxides with different concentrations 2, 4, 6, 8, 10, 15, and 20% by weight were studied. Powder of iron oxides of 63-μm particle size was casted with PEO polymer. Absorption UV spectra were collected in the wavelength range 300–800 nm by using a spectrophotometer. The optical energy gap and energy tail widths of localized states of the prepared composites were determined from Urbach formula. The electrical properties were studied using AC impedance measurements performed at different temperatures and in frequency range 100 kHz to 1 MHz. Impedance, dielectric constant, dielectric loss, and AC-conductivity showed frequency and temperature dependence. The thermal conductivity of the composites was studied as a function of iron oxides concentration and in temperature range 20–50°C. It was found that the thermal conductivity of the composites increases with filler concentration and temperature. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Optical and structural properties of (PANI-CSA-PMMA)/NiNPs nanocomposites thin films for organic optical filters

Synthesized nanocomposite of protonated polyaniline with camphorsulfonic acid (PANI-CSA) hosted in poly(methyl methacrylate) (PMMA) and incorporated with nickel nanoparticles (NiNPs) were coated as thin films on activated fused silica substrates using oxygen-plasma and spin coating techniques. Weight percent ratios of 0, 10, 20, 30, 60, and 90% of NiNPs with respect to PANI-CSA thin films have been studied in order to investigate the optical, structural, and morphological properties of (PANI-CSA-PMMA)/NiNPs by employing UV–Vis spectrometer, XRD, scanning electron microscopy (SEM), contact angle (CA) goniometry, impedance analyzer, and thermogravimetric analysis. Deduced refractive indices (n) from UV–Vis data were in the range from 1.5 up to 2.2. SEM micrographs show the typical crystalline structure of PANI was vanishing gradually with increasing the NiNPs content. Optical properties such as refractive index (n), extinction coefficient (k), absorption coefficient (α) as well as the band-gap energies (E_g) were mathematically deduced throughout the experimental transmittance and absorbance UV–Vis spectra. Calculated refractive indices (n) were in the range from 1.5 up to 2.2. Optical band-gap energies decrease in a monoexponential decay for samples up to 60% NiNPs/PANI-CSA, samples with 90% concentration had substantial drop in its value due to the NiNPs percolations. The incorporation with NiNPs leads to the development of a new morphological states (sheet-like heterostructure) which start to be obvious at 30%, at this concentration the CA was maxima (54°), at this concentration and the crystallite size are maximum and the CA was maximum (highest hydrophobicity). © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 48643.     

Characterization of a collection of Enterobacter sakazakii isolates from environmental and food sources

Enterobacter sakazakii has emerged as a rare cause of neonatal meningitis, septicemia and enterocolitis. Contaminated infant milk formula (IMF) has been identified as one infection route. A small number of clinical outbreaks have been epidemiologically linked to IMF contaminated post-pasteurization during manufacture and/or mishandled when reconstituted. Currently no agreed standardized typing protocol has been developed to trace E. sakazakii. The objectives of this study were to apply biochemical and genetic methods to characterize 51 environmental and food E. sakazakii isolates and 6 E. sakazakii type strains. Isolates were presumptively identified using biochemical profiles based on API 20E and ID32E methods and by culture on differential selective Druggan Forsythe Iversen (DFI) agar. Identification was subsequently confirmed by real time polymerase chain reaction (PCR). All but one of the isolates was identified as E. sakazakii by biochemical profiling. One isolate was identified as Escherichia vulneris by ID 32E and as Pantoea agglomerans by API 20E. All isolates produced green/blue colonies on DFI medium characteristic of this organism. Real time PCR could differentiate between E. sakazakii, Enterobacter spp. and other Enterobacteriacae. Analysis of RAPD banding patterns revealed 3 major clusters of E. sakazakii. There was a large degree of diversity noted amongst the remaining isolates. Our findings indicate that RAPD may be applied as a useful and reliable tool for direct comparison of E. sakazakii isolates providing traceability through the infant formula food chain.     

Measurement of low speed thermosiphonic flow

A flow visualization technique using dye injection and automatically actuated electronic timer was tested in the thermosiphonic flow region. Calibration of the system was obtained by: (1) Comparing the system measurements to the experimental cold flow rates. (2) Comparing the experimental (hot) system measurements obtained from a thermosiphon test rig with a computational model results simulating the flow within the thermosiphon. Test results include the flow of water and silicon oil. The findings show that the accuracy of the system is greatly enhanced with the use of a self actuating timer, and good agreement was found between measured mass flow rates and those predicted by the analysis.     

Treatment of chronic hepatitis C genotype 4 with alpha-interferon in Saudi Arabia: a multicenter study

BACKGROUND/AIM: Several studies have indicated that there are certain predictive factors (gender, duration of infection with HCV, cirrhosis and genotype of HCV) of a better response with alpha-interferon treatment in patients with chronic hepatitis C. The aim of this study was to evaluate these factors in Saudis and other Arab nationals with chronic hepatitis C-genotype 4-undergoing alpha-interferon treatment. METHODOLOGY: A multicenter study was conducted between 1992 and 1994 on 80 consecutive patients who were prospectively recruited and randomized in treatment and control groups. RESULTS: The results of this multicenter study indicated a low response rate to alpha-interferon with an overall response rate of 43%, of which 28% was complete. The sustained response was only 16%. Among the reasons for this low response in our study are the high percentage of patients with cirrhosis and the long infection interval, as about 80% of our HCV cases were community-acquired. CONCLUSION: Liver cirrhosis was found to be the main predetermining factor for response to interferon treatment. Genotype 4 was not a contributing factor to the difference in response rate.