Measurement of storage time, estimation of ion number and study of absorption line profile in a Paul trap

Europium (Eu⁺) ions were confined in a Paul trap and detected by non-destructive method. Storage time of Eu⁺ ions achieved in vacuum was improved by orders of magnitude employing buffer gas cooling. The experimentally detected signal was fitted to the ion response signal and the total number of ions trapped was estimated. It is found that the peak signal amplitude as well as the product of FWHM and the peak signal amplitude is proportional to the total number of trapped ions. The trapped ion secular frequency was swept at different rates and its effect on the absorption line profile was studied both experimentally and theoretically.     

Matrix metalloproteinase-1 inhibitor from the stem bark of Styrax japonica S. et Z

A bioassay-guided fractionation of the ethyl acetate soluble fraction from the stem bark of Styrax japonica S. et Z. (Styracaceae) yielded two new lignan compounds, styraxjaponoside A (1) and styraxjaponoside B (2), along with three known compounds, matairesinoside (3), egonol glucoside (4), and dihydrodehydrodiconiferyl alcohol 9'-O-glucoside (5). The structures of compounds 1-5 were determined by spectroscopic method, as well as 1D- and 2D-NMR (HSQC, 1H-1H COSY, and HMBC) spectroscopy. Among them, compound 2 exhibited potent inhibitory activity against matrix metalloproteinase (MMP)-1, and prevented the UV-induced changes in the MMP-1 expression. In addition, compounds 3 and 5 were isolated from this plant for the first time.     

Trapped electron mode turbulence driven intrinsic rotation in Tokamak plasmas

Progress from global gyrokinetic simulations in understanding the origin of intrinsic rotation in toroidal plasmas is reported. The turbulence-driven intrinsic torque associated with nonlinear residual stress generation due to zonal flow shear induced asymmetry in the parallel wave number spectrum is shown to scale close to linearly with plasma gradients and the inverse of the plasma current, qualitatively reproducing experimental empirical scalings of intrinsic rotation. The origin of current scaling is found to be enhanced k(∥) symmetry breaking induced by the increased radial variation of the safety factor as the current decreases. The intrinsic torque is proportional to the pressure gradient because both turbulence intensity and zonal flow shear, which are two key ingredients for driving residual stress, increase with turbulence drive, which is R/L(T(e)) and R/L(n(e)) for the trapped electron mode.     

Correction: Dermatan sulfate in tunicate phylogeny: Order-specific sulfation pattern and the effect of [→4IdoA(2-Sulfate)β-1→3GalNAc(4-Sulfate)β-1→] motifs in dermatan sulfate on heparin cofactor II activity

After the publication of the work entitled "Dermatan sulfate in tunicate phylogeny: Order-specific sulfation pattern and the effect of [→4IdoA(2-Sulfate)β-1→3GalNAc(4-Sulfate)β-1→] motifs in dermatan sulfate on heparin cofactor II activity", by Kozlowski et al., BMC Biochemistry 2011, 12:29, we found that the legends to Figures 2 to 5 contain serious mistakes that compromise the comprehension of the work. This correction article contains the correct text of the legends to Figures 2 to 5.     

Nonlinear triad interactions and the mechanism of spreading in drift-wave turbulence

We present the results of a derivation of the fluctuation energy transport matrix for the two-field Hasegawa-Wakatani model of drift wave turbulence. The energy transport matrix is derived from a two-scale direct interaction approximation assuming weak turbulence. We examine different classes of triad interactions and show that radially extended eddies, as occurs in penetrative convection, are the most effective in turbulence spreading. We show that in the near-adiabatic limit internal energy spreads faster than the kinetic energy. Previous theories of spreading results are discussed in the context of weak turbulence theory.     

Dimethyl carbonate synthesis via transesterification of ethylene carbonate and methanol using ionic liquid catalysts immobilized on mesoporous cellular foams

Dimethyl carbonate (DMC) was synthesized via transesterification of ethylene carbonate and methanol with ionic liquid catalysts. For this reaction, 1,4-diazobicyclo[2.2.2]octane (DABCO), [Choline]OH, and [BMIM]Cl were used as a homogeneous catalyst, and hydrotalcite, [DABCO]OH@MCF, [DABCO]Cl@MCF, and DABCO/MCF were used as a heterogeneous catalyst. To support the ionic liquids, mesoporous cellular foam (MCF) was prepared and characterized by SEM, TEM and BET surface area analyzer. The average cell and window sizes of the prepared MCF were 34.4 and 21.3 nm, respectively. The prepared MCF had a well structured three-dimensional structure. Among the homogeneous catalysts used, DABCO showed the highest DMC yield about 84 %, and among the heterogeneous catalysts, [DABCO]OH@MCF showed the highest DMC yield about 77 %. In the reusability test of the used catalysts, there was only 8 % point decrease in DMC yield with [DABCO]OH@MCF, whereas 58 percent point decrease in DMC yield with DABCO/MCF after four times recycling tests. The effects of an anion on the catalytic activity were investigated. The optimum reaction condition for DMC synthesis was also investigated with [DABCO]OH@MCF catalyst.     

Interspecies Interaction of Signal Peptide PapR Secreted by <Emphasis Type="Italic">Bacillus cereus</Emphasis> and Its Effect on Production of Antimicrobial Peptide

This study was carried out to investigate the interspecies interaction of PapR peptide secreted by Bacillus cereus on production of BSAP-254, an antimicrobial peptide produced by Bacillus subtilis SC-8 isolated from the Korean fermented soybean paste and exhibited narrow antagonistic activity against the B. cereus group, but not against other foodborne pathogens. PapR is a signal peptide that activates PlcR, which is a pleiotropic regulator controlling the expression of various virulence factors in B. cereus. When B. subtilis SC-8 was co-cultured with B. cereus, it completely inhibited the growth of B. cereus within 12 h, and the rate of BSAP-254 production was increased 34.2% at 12 h. Furthermore, 5 μM of synthetic PapR peptide added to the culture of B. subtilis SC-8 increased the rate of BSAP-254 production up to 59.7%. The growth of B. subtilis SC-8, however, was not significantly different with or without the addition of PapR. When B. cereus papR mutant was co-cultured with B. subtilis SC-8, the growth of the mutant was not inhibited and the rate of BSAP-254 production was decreased by 45%.