Recognize three different human telomeric G-quadruplex conformations by quinacrine

Recognition of different human telomeric G-quadruplex structures has been a very important task for developing anti-cancer drug design. However, it also is a very challenging question since multiple conformational isomers of telomeric G-quadruplexes coexist under some conditions. Here, three different conformations including parallel, antiparallel, and mixed-type telomeric G-quadruplex structures have been well recognized by quinacrine (QNA) through monitoring its absorption, fluorescence, and fluorescence lifetime spectra. The multiple structures of H22 G-quadruplexes under physiological K(+) conditions could also be easily determined to coexist as mixed-type and antiparallel G-quadruplexes. The recognition mechanism based on the different binding affinity and binding sites has been further elucidated by association with the nuclear magnetic resonance (NMR) results.     

Effects of Co-substitutes on multiferroic properties of Bi5FeTi3O15 ceramics

The samples Bi₅FeTi₃O₁₅ (BFTO) and Bi₅Fe_0.5Co_0.5Ti₃O₁₅ (BFCT) were prepared by incorporating BiFeO₃ (BFO) and BiFe_0.5Co_0.5O₃ (BFCO) into the host Bi₄Ti₃O₁₂ (BTO) using the solid state reaction technique. The Raman shift data indicate that the as-prepared materials are of the four-layer Aurivillius phase with an orthorhombic symmetry. At room temperature (RT) and under a driving electric field of 230 kV/cm, the half substitution of Fe by Co ions is found to result in the increase in the remanent polarization $\left(2P_r\right)$ by about 35% and simultaneously the decrease in $2E_c$ by about 41%, respectively. The magnetic moment at least tripled its value by substituting half Fe ions by Co ions. The $2M_r$ of BFCT is about three thousand times the value of BFTO.     

Diamond-shaped acoustic concentrator with homogeneous material parameters

Based on coordinate transformation method, the two-dimensional and three-dimensional acoustic concentrators with diamond shape composed of nonsingular homogeneous materials are designed in this paper. The mass density tensor and bulk modulus of the acoustic concentrators are derived. Performance of the concentrators is confirmed by full-wave simulation. The work represents an important progress towards the practical realization of the metamaterial-assisted acoustic concentrator and expands the application of the coordinate transformation method.     

Application of a viscoplastic material model on a combined quasi-static-electromagnetic forming process

The prediction and simulation of material behavior by finite element methods has become indispensable. Furthermore, various phenomena in forming processes lead to highly differing results. In this work, we have investigated the process chain on a cross-shaped cup in cooperation between the Institute of Applied Mechanics (IFAM) of the RWTH Aachen and the Institute of Forming Technology and Lightweight Construction (IUL) of the TU Dortmund. A viscoplastic material model based on the multiplicative decomposition of the deformation gradient in the context of hyperelasticity has been used [1,2]. The finite strain constitutive model combines nonlinear kinematic and isotropic hardening and is derived in a thermodynamically consistent setting. This anisotropic viscoplastic model is based on the multiplicative decomposition of the deformation gradient in the context of hyperelasticity. The kinematic hardening component represents a continuum extension of the classical rheological model of Armstrong-Frederick kinematic hardening. The constitutive equations of the material model are integrated in an explicit manner and implemented as a user material subroutine in the commercial finite element package LS-DYNA with the electromagnetical module. The aim of the work is to show the increasing formability of the sheet by combining quasi-static deep drawing processes with high speed electromagnetic forming. (© 2013 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim)     

Microenvironmental and conformational structure of triblock copolymers in aqueous solution by 1H and 13C NMR spectroscopy

1H and 13C nuclear magnetic resonance (NMR) spectra of poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) (PEO-PPO-PEO) triblock copolymers in D2O solutions have been systematically investigated. The detailed assignments of various 1H and 13C NMR signals are presented. The hyperfine structure of PO -CH2- protons was clearly assigned, the arising reason of this hyperfine structure was attributed to the influence of the chiral center of -CHCH3- groups and the direct coupling between the PO -CH2- and -CH3 protons. The external standard 2,2-dimethyl-2-silapentane-5-sulfonate sodium salt (DSS) was firstly applied in this system. Accurate chemical shift values referenced to the external standard DSS were obtained. 1H NMR chemical shift of PO -CH2- and -CH3 signals shows a larger decrease in ppm values than that of EO -CH2- signal with the increase of PPO/PEO ratio or temperature indicating that PO segments exist in a more hydrophobic microenvironment. A new resonance signal assigned to the PO -CH2- protons appeared when the temperature is above the CMT, which is attributed to the breakdown of the intra-molecular (C-H)...O hydrogen bond between the PO -CH2- protons and the ester oxygens. The breakdown of this intra-molecular hydrogen bond may result in a decrease of gauche conformers of the PPO chain. The increase of 13C NMR chemical shift of block copolymers validates this conformational change assumption. It can be inferred that the amount of gauche conformers decreases whereas that of trans conformers increases in both PO and EO chains when elevating the PPO/PEO ratio or temperature. The observed 13C NMR chemical shifts of PO segments show a bigger increase than those of EO segments, supporting the formation of a nonpolar microenvironment around PO segments.     

Study on a novel circulating cooling solid-phase microextraction method

A novel solid-phase microextraction (SPME) setup, circulating cooling solid-phase microextraction (CC-SPME), is developed for determining organochlorine pesticides (OCPs) in water. The linearity area of this method is 0.5-120 microg/l, its RSD value is less than 10% and detection limit is in the low ng/l when it is used to detect gamma-hexachlorocyclohexane, which is better than traditional headspace SPME (HS-SPME) and direct immersion SPME (DI-SPME) methods. The influence of factors such as pH, ionic intensity, adsorption time, and adsorption temperature were also investigated, respectively.     

Working group report: Heavy-ion physics and quark-gluon plasma

This is the report of Heavy Ion Physics and Quark-Gluon Plasma at WHEPP-09 which was part of Working Group-4. Discussion and work on some aspects of quark-gluon plasma believed to have created in heavy-ion collisions and in early Universe are reported.     

Effects of Exogenous Methyl Jasmonate on the Biosynthesis of Shikonin Derivatives in Callus Tissues of Arnebia euchroma

The shikonin derivatives, accumulated in the roots of Arnebia euchroma (Boraginaceae), showed antibacterial, anti-inflammatory, and anti-tumor activities. To explore their possible biosynthesis regulation mechanism, this paper investigated the effects of exogenous methyl jasmonate (MJ) on the biosynthesis of shikonin derivatives in callus cultures of A. euchroma. The main results include: Under MJ treatment, the growth of A. euchroma callus cultures was not inhibited, but the expression level of both the genes involved in the biosynthesis of shikonin derivatives and their precursors and the genes responsible for intracellular localization of shikonin derivatives increased significantly in the Red Strain (shikonin derivatives high-producing strain). The quantitative analysis showed that six out of the seven naphthoquinone compounds under investigation increased their contents in the MJ-treated Red Strain, and in particular, the bioactive component acetylshikonin nearly doubled its content in the MJ-treated Red Strain. In addition, it was also observed that the metabolic profiling of naphthoquinone compounds changed significantly after MJ treatment, and the MJ-treated and MJ-untreated strains clearly formed distinct clusters in the score plot of PLS-DA. Our results provide some new insights into the regulation mechanism of the biosynthesis of shikonin derivatives and a possible way to increase the production of naphthoquinone compounds in A. euchroma callus cultures in the future.     

Quantum space-times in the year 2002

We review certain emergent notions on the nature of space-time from noncommutative geometry and their radical implications. These ideas of space-time are suggested from developments in fuzzy physics, string theory, and deformation quantization. The review focuses on the ideas coming from fuzzy physics. We find models of quantum space-time like fuzzy S ⁴ on which states cannot be localized, but which fluctuate into other manifolds like CP³. New uncertainty principles concerning such lack of localizability on quantum space-times are formulated. Such investigations show the possibility of formulating and answering questions like the probability of finding a point of a quantum manifold in a state localized on another one. Additional striking possibilities indicated by these developments is the (generic) failure of CPT theorem and the conventional spin-statistics connection. They even suggest that Planck’s ‘constant’ may not be a constant, but an operator which does not commute with all observables. All these novel possibilities arise within the rules of conventional quantum physics, and with no serious input from gravity physics.