A simple sample pretreatment device with supported liquid membrane for direct injection of untreated body fluids and in‐line coupling to a commercial CE instrument

A simple sample pretreatment device was developed employing extractions across supported liquid membranes (SLMs) and in‐line coupling to a commercial CE instrument. The device consisted of two polypropylene conical units interspaced with a polypropylene planar SLM, which were impregnated with 1‐ethyl‐2‐nitrobenzene. The two units and the SLM were pressed against each other, donor unit was filled with 40 μL of an untreated body fluid and acceptor unit with 40 μL of DI water. The device was then placed into conventional CE vial fitted with a soft spring, which was depressed during injection into CE capillary and ensured that the SLM was not ruptured. Position of separation capillary injection end and high‐voltage electrode in the CE instrument was optimized in order to ensure efficient injection of pretreated body fluids. The device can be easily assembled/disassembled and SLMs can be replaced after each extraction thus minimizing sample carry‐over, avoiding tedious SLM regeneration, and reducing total pretreatment time and costs. The pretreatment device was examined by direct injection of human urine and serum spiked with nortriptyline, haloperidol, and loperamide. The basic drugs were diffusionaly transported across the SLM within 10 min and were injected into the separation capillary directly from the SLM surface in the acceptor unit, whereas matrix components were retained by the SLM. The in‐line SLM‐CE method showed good repeatability of peak areas (3.8–11.0%) and migration times (below 1.4%), linear relationship (r² = 0.990–0.999), and low LODs (12–100 μg/L).     

Direct conversion of natural gas to higher hydrocarbons: A review

Direct conversion of methane to higher hydrocarbons is an effective process to solve the problem of natural gas utilization. Although remarkable progress has been achieved on the dehydro-aromatization of methane (DAM), low conversion caused by severe thermodynamic limitations, coke formation, and catalysis deactivation remain important drawbacks to the direct conversion process. Molybdenum catalysts supported on HZSM-5 type zeolite support are among the most promising catalysts. This review focuses on the aspects of direct methane conversion, in terms of catalysts containing metal and support, reaction conditions, and conversion in different types of reactors. The reaction mechanism for this catalytic process is also discussed.     

Radiological dose assessment of naturally occurring radioactive materials in concrete building materials

Previous studies have shown that the natural radioactivity contained in building materials have significantly influenced the dose rates in dwelling. Exposure to natural radiation in building has been of concerned since almost 80 % of our daily live are spend indoor. Thus, the aim of the study is to assess the radiological risk associated by natural radioactivity in soil based building materials to dwellers. A total of 13 Portland cement, 46 sand and 43 gravel samples obtained from manufacturers or bought directly from local hardware stores in Peninsular of Malaysia were analysed for their radioactivity concentrations. The activity concentrations of ²²⁶Ra, ²³²Th and ⁴⁰K in the studied building materials samples were found to be in the range of 3.7–359.3, 2.0–370.8 and 10.3–1,949.5 Bq kg^?1 respectively. The annual radiation dose rates (μSv year^?1) received by dwellers were evaluated for 1 to 50 years of exposure using Resrad-Build Computer Code based on the activity concentration of ²²⁶Ra, ²³²Th and ⁴⁰K found in the studied building material samples. The rooms modelling were based on the changing parameters of concrete wall thickness and the room dimensions. The annual radiation dose rates to dwellers were found to increase annually over a period of 50 years. The concrete thicknesses were found to have significantly influenced the dose rates in building. The self-absorption occurred when the concrete thickness was thicker than 0.4 m. Results of this study shows that the dose rates received by the dwellers of the building are proportional to the size of the room. In general the study concludes that concrete building materials; Portland cements, sands, and gravels in Peninsular of Malaysia does not pose radiological hazard to the building dwellers.     

Zeaxanthin Production by Novel Marine Isolates from Coastal sand of India and its Antioxidant Properties

Zeaxanthin carotenoids are class of commercially important natural products and diverse biomolecules produced by plants and many microorganisms. Bacteria often produce a cocktail of polar and nonpolar carotenoids limiting their industrial applications. Marine members of the family Flavobacteriaceae are known to produce potential carotenoids such as astaxanthin and zeaxanthin. A few bacterial species have been reported for the predominant production zeaxanthin. Here, we report the molecular identification of the zeaxanthin as a major carotenoid produced by two novel bacteria (YUAB-SO-11 and YUAB-SO-45) isolated from sandy beaches of South West Coast of India and the effect of carbon sources on the production of zeaxanthin. The strains were identified based on the 16S rRNA gene sequencing as a member of genus Muricauda. The closest relatives of YUAB-SO-11 and YUAB-SO-45 were Muricauda aquimarina (JCM 11811^T) (98.9 %) and Muricauda olearia (JCM 15563^T) (99.2 %), respectively, indicating that both of these strains might represent a novel species. The highest level of zeaxanthin production was achieved (YUAB-SO-11, 1.20?±?0.11 mg g^?1) and (YUAB-SO-45, 1.02?±?0.13 mg g^?1) when cultivated in marine broth supplemented with 2 % NaCl (pH 7) and incubated at 30 °C. Addition of 0.1 M glutamic acid, an intermediate of citric acid cycle, enhanced the zeaxanthin production as 18 and 14 % by the strains YUAB-SO-11 and YUAB-SO-45 respectively. The zeaxanthin showed in vitro nitric oxide scavenging, inhibition of lipid peroxidation, and 2,2-diphenyl-1-picryl hydrazyl scavenging activities higher than the commercial zeaxanthin. The results of this study suggest that two novel strains YUAB-SO-11 and YUAB-SO-45 belonging to genus Muricauda produce zeaxanthin as a predominant carotenoid, and higher production of zeaxanthin was achieved on glutamic acid supplementation. The pigment showed good in vitro antioxidant activity, which can be exploited further for commercial applications.     

Efficacy of zinc and tourmaline in mitigating corrosion of carbon steel in non-flow mode

Laboratory corrosion immersion tests were carried out to investigate the effectiveness of a physical water treatment (PWT) using zinc and ceramic tourmaline-based catalytic materials for the control of carbon steel corrosion in acidic still water (i.e., pH 4.5–5). The tests were carried out at different water temperatures over 168 h. Our results showed a maximum of 22 % reduction in the corrosion rate using PWT in comparison with the control case. Furthermore, the corrosion products depicted more agglomerated particles after the PWT treatment. In both cases, differences were observed in the crystal structures, showing in general lower corrosion activity when PWT was used. The present results could find potential applications in water distribution systems and where metallic materials are exposed to stagnant acidic water.     

Synthesis, characterization and fluorescence studies of 3,5-diaryl substituted 2-pyrazolines

A series of 2-pyrazolines have been synthesized from α, β unsaturated ketones and hydrazine hydrate with acetic/formic acid in ethanol/DMSO. The structures of 2-pyrazolines have been established by spectroscopic techniques i.e. UV, IR, (1)H NMR, (13)C NMR and micro element analysis. Fluorescence spectra were recorded in the solution at fixed concentration and same excitation wavelength at 290 nm. The absorption band positions of all the compounds broadly lie between 280 and 336 nm and fluorescence band positions in the range between 300 and 370 nm, the near ultraviolet region.     

Chemical diversity in Mentha spicata: antioxidant and potato sprout inhibition activity of its essential oils

The essential oils from fresh aerial parts of Mentha spicata L. collected from ten different natural habitats of Uttarakhand, India were analyzed by a combination of GC, GC/MS and NMR spectroscopy. The analysis revealed that monoterpenoids (46.1%-91.6%), mainly carvone (15.3%-68.5%), piperetenone oxide (24.0%-79.2%) and alpha-humulene (0.1%-29.9%), were the major constituents of the essential oils, but with significant qualitative and quantitative differences among the other constituents. Cluster analysis of the oil composition was carried out in order to discern the differences and similarities within different accessions collected from different natural habitats. The essential oils were also screened for their antioxidant activities by chelating properties of Fe2+, DPPH radical-scavenging activity, and their reducing power. The essential oils of two chemo variants (viz. carvone and piperetenone oxide types) were also tested for potato (Solanum tuberosum L.) sprout suppressant activity. The results showed that these oils exhibit good sprout inhibition activity in comparison to CIPC and iodine, the standard sprout suppressant.     

Effect of polymer molecular weight on the fiber morphology of electrospun mats

In this work, different fractions of solvent-induced polymer degraded solution were mixed with freshly prepared solution of same polymer, and its effect on fiber morphology of electrospun mats was investigated. Nylon-6 solution in formic acid was allowed to degrade for 3 weeks and different fractions of it were mixed with freshly prepared nylon-6 solution to get the electrospun mats. FE-SEM images of the mats indicated that the a large amount of sub-nanofibers (<50 nm in diameter) in the form of spider-net like structures were achieved by tailoring the amount of solvent degraded polymer solution in the freshly prepared nylon-6 solution. Large quantity of these ultrafine sub-nanofibers present in electrospun nylon-6 mats could increase its hydrophilicity and mechanical strength. The decreased average pore diameter and increased BET surface area of the mat, caused by spider-net like structure, can make it as a potential candidate for air/water filtration.     

Photonic chip-based all-optical XOR gate for 40 and 160 Gbit/s DPSK signals

We demonstrate a photonic chip-based all-optical exclusive-OR (XOR) gate for phase-encoded optical signals via four-wave mixing in a highly nonlinear, dispersion-engineered chalcogenide (As2S3) planar waveguide. We achieve error-free, XOR operation for 40?Gbit/s differential phase shift keying (DPSK) optical signals with no power penalty. The effectiveness and broad bandwidth operation of our approach is highlighted by implementing an XOR gate for 160?Gbit/s DPSK signals.     

Fabrication of highly porous poly (ɛ-caprolactone) fibers for novel tissue scaffold via water-bath electrospinning

A non-toxic route was used for the preparation of silver nanoparticles using tryptophan (Trp) as reducing/stabilizing agent in the presence of cetyltrimethyl ammonium bromide (CTAB). Role of water soluble neutral polymer poly(vinylpyrrolidone) (PVP) has been studied on the growth of yellow colour silver nanoparticle formation. The synthesized nanostructures were characterized by UV–Visible absorption spectroscopy, transmission electron microscopy (TEM) by observing the size and distribution of silver nanoparticles. As the reaction proceeded, particles grew up to about 10 and 20 nm in the presence and absence of PVP, respectively, as determined by TEM. The formed nanoparticles showed the highest absorption plasmon band at 425 nm. Rate of silver sol formation increases with the [Trp], [CTAB] and [PVP], reaching a limiting value and then decreases with the increase in concentrations of these reagents. It was observed that nanoparticles are spherical, aggregated and poly dispersed in the absence and presence of PVP, respectively. On the basis of kinetic data, a suitable mechanism is proposed and discussed for the silver sol formation.