Gamma-irradiated onions as a biological indicator of radiation dose.

Post-irradiation identification and dose estimation are required to assess the radiation-induced effects on living things in any nuclear emergency. In this study, radiation-induced morphological/cytological changes i.e., number of root formation and its length, shooting length, reduction in mitotic index, micronuclei formation and chromosomal aberrations in the root tip cells of gamma-irradiated onions at lower doses (50-2000 cGy) are reported. The capabilities of this biological species to store the radiation-induced information are also studied.     

Chlorella minutissima—A Promising Fuel Alga for Cultivation in Municipal Wastewaters

It is imperative to slash the cost of algal oil to less than $50 bbl^?1 for successful algal biofuel production. Use of municipal wastewater for algal cultivation could obviate the need for freshwater and the nutrients—N and P. It would also add CO₂ through bacterial activity. Chlorella minutissima Fott et Nova dominated the entire phycoflora year around and through each stage of the wastewater treatment at the oxidation pond system of Wazirabad (Delhi) in India. The ability to grow so profusely in such varied and contrasting situations made this alga unique. Besides pollution tolerance, it grew heterotrophically in dark under acidic conditions and as a mixotroph in presence of light over a range of organic C substrates. It could utilize both ammoniacal and nitrate nitrogen, survived anaerobicity, 5% NaCl and ?10 bar of osmotic stress. C. minutissima grew at pH 4–11 and raised the pH set initially by 1 to 3 units in 7.5 h. It showed gigantism and largely kept afloat in presence of utilizable organic carbon, while flocculated in mineral medium and on aging. The alga also possessed potential for biofuel production. The studied parameters indicate why C. minutissima was a potential biomass builder in municipal sewage and could be used to determine which other alga(e) may serve the purpose.     

Bounds on an anomalous dijet resonance in W+jets production in pp collisions at √s = 1.96 TeV

We present a study of the dijet invariant mass spectrum in events with two jets produced in association with a W boson in data corresponding to an integrated luminosity of 4.3 fb(-1) collected with the D0 detector at √s = 1.96 TeV. We find no evidence for anomalous resonant dijet production and derive upper limits on the production cross section of an anomalous dijet resonance recently reported by the CDF Collaboration, investigating the range of dijet invariant mass from 110 to 170 GeV/c(2). The probability of the D0 data being consistent with the presence of a dijet resonance with 4 pb production cross section at 145 GeV/c(2) is 8×10(-6).     

Search for Resonant WW and WZ Production in pp collisions at √s=1.96 TeV

We search for resonant WW or WZ production by using up to 5.4 fb(-1) of integrated luminosity collected by the D0 experiment in run II of the Fermilab Tevatron Collider. The data are consistent with the standard model background expectation, and we set limits on a resonance mass by using the sequential standard model W' boson and the Randall-Sundrum model graviton G as benchmarks. We exclude a sequential standard model W' boson in the mass range 180-690 GeV and a Randall-Sundrum graviton in the range 300-754 GeV at 95% C.L.     

The effect of length of single‐walled carbon nanotubes (SWNTs) on electrical properties of conducting polymer–SWNT composites

DC conductivity of conjugated polymer‐single‐walled carbon nanotube (SWNT) composite films has been measured for different SWNT concentrations. The composite was prepared by dispersing SWNTs in the poly (3‐octylthiophene), P3OT matrix already dissolved in xylene. The conductivity of the composite films showed a rapid increase as the SWNT concentration increases beyond a certain value. This behavior is explained in terms of percolating paths provided by the SWNTs in the volume of polymer matrix. To investigate the effect of length of nanotubes on the percolation conductivity, different SWNT samples were employed with similar diameter but varying tube lengths. It was found that the conductivity of the composite films is strongly dominated by the length of the nanotubes. Lower percolation limit and high conductivity value of composite films is observed for longer nanotubes. Furthermore, the conductivity is observed to be dependent on the size of the host polymer molecule also. © 2009 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 48: 89–95, 2010     

The spherical vessel with anisotropic creep properties considering large strains

The effect of material anisotropy on creep of pressurized thick-walled spherical vessel has been discussed considering the large strain theory. It is found that the creep strain varies with varying anisotropy of the material. The results obtained for the anisotropic case have been compared with those obtained for the isotropic case and it is observed that the stress and strain distribution in the wall of the vessel is strikingly different for the two cases.     

Radar transparent glass fabric reinforced polyetherimide/Cloisite 30B nanocomposites

High performance radar transparent materials (RTMs) are important materials for the fabrication of radomes, nosecones, etc. of high velocity aerospace vehicles. RTMs with good mechanical performance and temperature capability are required for such applications. Toward this, fabric reinforced nano‐reinforced matrix composites (FRNCs), using reinforcing E‐glass fabric in Cloisite 30B reinforced polyetherimide (PEI) nanocomposite matrix (GNRPEI), was prepared. The properties of GNRPEI were evaluated and compared with E‐glass fabric reinforced PEI composites (GRPEI) with special reference to their radar transparent character for aerospace applications. Tensile and flexural properties along with interlaminar shear strength of GRPEI were observed to be lower than those of GNRPEI. Thermal behavior of both the composites was similar in differential scanning calorimetry and thermal gravimetric analysis. But, in dynamic mechanical analysis, an increase in storage modulus and decrease in loss tangent were observed in GNRPEI compared to GRPEI. The values of dielectric constant and loss tangent of GNRPEI were lesser than those of GRPEI, but no significant difference was observed in the values of transmission and reflection losses for both the composites at 8–12 GHz frequency. FRNCs, based on organoclay reinforced PEI matrix, hold good promise as high performance RTMs. Copyright © 2010 John Wiley & Sons, Ltd.     

Heavy metals adsorption by novel EDTA-modified chitosan-silica hybrid materials

Ionic liquid based microemulsions were characterized by absorption solvatochromic shifts, (1)H NMR and kinetic measurements in order to investigate the properties of the ionic liquid within the restricted geometry provided by microemulsions and the interactions of the ionic liquid with the interface. Experimental results show a significant difference between the interfaces of normal water and the new ionic liquid microemulsions. Absorption solvatochromic shift experiments and kinetic studies on the aminolysis of 4-nitrophenyl laurate by n-decylamine show that the polarity at the interface of the ionic liquid in oil microemulsions (IL/O) is higher than at the interface of water in oil microemulsions (W/O) despite the fact that the polarity of [bmim][BF(4)(-)] is lower than the polarity of water. (1)H NMR experiments showed that an increase in the ionic liquid content of the microemulsion led to an increase in the interaction between [bmim][BF(4)(-)] and TX-100. The reason for the higher polarity of the microemulsions with the ionic liquid can be explained in terms of the incorporation of higher levels of the ionic liquid at the interface of the microemulsions, as compared to water in the traditional systems.     

Drevogenin A und Drevogenin B,zusätzlicher Strukturbeweis. Glykoside und Aglykone, 306. Mitteilung

Drevogenin B is shown to be 11-O-acetyl-drevogenin P. The earlier derived structure for drevogenin A (11-O-acetyl-drevogenin P) is further confirmed by conversion of 3-O-acetyl-drevogenin A.