Level crossing resonance due to chlorine nuclei in a free radical

Muonium adds to allyl chloride, CH₂=CHCH₂Cl, to form two radicals: MuCH₂CHCH₂Cl (main product) and CH₂CHMuCH₂Cl (minor product). Both radicals were fully characterized bySR andLCR. In the main product, the LCR lines due to the³⁵Cl and³⁷Cl nuclei were observed. Also, the temperature dependence of various hyperfine coupling constants (hfc) indicates that both Mu and Cl eclipse the unpaired electronp ₂-orbital in the minimum energy conformation. For the fragment-CH₂Cl, the presence of Mu in the-position is found to affect significantly the hfc of Cl in the-position; an internal rotational barrier of 12 kJ mol^–1 was estimated using a simpleV ₂ torsional potential.     

μSR Investigation of ethyl radicals adsorbed on silica

SR spectra of the ethyl radical adsorbed on porous silica were observed in transverse and in longitudinal magnetic fields in the temperature range 190–298 K. The line widths reflect the dynamic partial averaging of the hyperfine anisotropy due to reorientation and surface diffusion.     

Comparative performance trials with yeast andZymomonas for fuel alcohol production from corn

Applied Biochemistry and Biotechnology - Z.mobilis (ATCC 29191) produced ethanol in significantly greater yield thanS. cerevisiae, (0.49 vs 0.45 g ethanol/g glucose entering the system), in...     

IMPAIRED REPAIR OF UVC-INDUCED DNA DAMAGE IN L5178Y-R CELLS: DNA UNWINDING STUDIES WITH THE USE OF 1-β-D-ARABINOFURANOSYL CYTOSINE

Abstract— L5178Y-R (LY-R) and L5178Y-S (LY-S) cells differ in sensitivity to UVC radiation (D₀: 2.8 and 9.0 J/m²respectively, for cells exposed in Fischer's medium). We used these cells and a DNA unwinding technique in conjunction with 1-β-D-arabinosyl cytosine to determine DNA strand breaks accumulating as a result of enzymatic incision during DNA repair. Following UVC exposure DNA strand break accumulation was observed in LY-S cells but not in LY-R cells. The repair defect in LY-R cells is accompanied by a delayed recovery of [³H]thymidine incorporation.     

Efficient calculation of SAMPL4 hydration free energies using OMEGA,SZYBKI, QUACPAC,and Zap TK

Several submissions for the SAMPL4 hydration free energy set were calculated using OpenEye tools, including many that were among the top performing submissions. All of our best submissions used AM1BCC charges and Poisson–Boltzmann solvation. Three submissions used a single conformer for calculating the hydration free energy and all performed very well with mean unsigned errors ranging from 0.94 to 1.08 kcal/mol. These calculations were very fast, only requiring 0.5–2.0 s per molecule. We observed that our two single-conformer methodologies have different types of failure cases and that these differences could be exploited for determining when the methods are likely to have substantial errors.     

High resolution magneto-optical studies of p-InSb

High resolution photoconductivity and transmission spectra in p-InSb are obtained over a wide temperature range at magnetic fields from 9 to 100 kG using a CO₂ laser. The low temperature results are described in terms of hole transitions from the acceptor ground state to excited states associated with free light-hole Landau states.     

XRF spectrometer calibration for copper determination in wood

Method of X‐ray fluorescence (XRF) spectrometer calibration for copper analysis in wood was elaborated. Copper salt standard solutions for XRF measurements of liquid samples were prepared, and calibration curve of copper content dependence on impulse counts was determined. Specimens of pine wood (Pinus sylvestris L.) were treated with different solutions of copper‐based preservative (alkaline copper quarternary ammonium compound type) applying model low‐pressure preservation process. After treatment, wood specimens were sliced into six pieces, and exposed surfaces were analyzed using mapping option of XRF spectrometer. Then, wood from each analyzed surface was peeled with abrasive paper and dissolved in 65% nitric (V) acid. Copper content in solutions was determined using obtained calibration curve, and calibration dependence of copper content in wood on the average impulse counts on particular surfaces was calculated. Obtained results of copper content were consistent with values calculated on the basis of differences of samples weight before and after treatment. It confirms that proposed procedure is correct, and obtained equation may be used for unknown samples examination. Copyright © 2012 John Wiley & Sons, Ltd.     

Theory of resonant magneto-polaron in GaAs-GaAlAs heterostructure

Energies of resonant polarons related to interaction of inversion electrons in GaAs with optic phonons in the presence of a magnetic field are calculated and compared with recent cyclotron resonance measurements on a GaAs-GaAlAs heterostructure. The nonparabolocity of the conduction band is accounted for in the triangular potential approximation. The screening of polar interaction is neglected. Using an intensity of the confining electric field as a fitting parameter a very good agreement between the theory and the experiment is obtained.     

High spatial resolution ellipsometer for characterization of epitaxial graphene

An ellipsometer with 3μm×5μm spot size constructed with a single focusing and imaging element is used to measure the layer number of exfoliated graphene on glass and expitaxial graphene on SiC. Ellipsometric sensitivity to graphene layer number increases with decreasing layer number and decreasing substrate refractive index. Single-atomic-layer sensitivity has been achieved. High spatial resolution imaging and ellipsometry is useful for rapid characterization of epitaxially grown graphene films.