The Wigner solution of quark gap equation at nonzero current quark mass and partial restoration of chiral symmetry at finite chemical potential

According to the generally accepted phase diagram of QCD, at low temperature and high baryon number density the chiral phase transition of QCD is of first order and the co-existence of the Nambu-Goldstone phase and the Wigner phase should appear. This is in conflict with the usual claim that the quark gap equation has no Wigner solution in the case of nonzero current quark mass. In this paper we analyze the reason why the Wigner solution does not exist in the usual treatment and try to propose a new approach to discuss this question. As a first step, we adopt a modified Nambu-Jona-Lasinio (NJL) model to study the Wigner solution at finite current quark mass. We then generalize this approach to the case of finite chemical potential and discuss partial restoration of chiral symmetry at finite chemical potential and compare our results with those in the normal NJL model.Comment: 7 pages, 5 figures, and 1 table, discussion at finite chemical potential adde

Polypropylene based anion exchange fiber for enrichment and determination of trace indium by GFAAS

Indium was enriched and separated by a new polypropylene based anion exchange fiber before determined by graphite furnace atomic absorption spectrometry (GFAAS). Indium can be enriched quantitatively by 0.1 g of fiber at the flow rate within 6 mL·min-1 in the pH 4 and can be desorbed quantitatively with 10 mL of 1.0 M nitric acid from the fiber column. The fibers were soaked in 2 M sodium hydroxide sodium hydroxide solution for activation and were washed with distilled water at least thirty times until neutral for regeneration, The saturated capacity of the fiber for In(III) was 1.32 mg·g-1. The activation energy (Ea) of the fiber adsorption In(III) was 89.3 kJ·mol-1. The method was used to enrich trace In(III) in artificial samples solution and zinc concentrate solution before determination. The method detection limit was 0.08 ng·mL-1, the recoveries were 96.8-101%, and the relative standard deviations (RSD) were 0.1-2.1%. KEY WORDS: Anion exchange fiber, Separation, Enrichment, Indium, GFAAS Bull. Chem. Soc. Ethiop. 2011, 25(2), 295-298

Inversion formula of multifractal energy dissipation in 3D fully developed turbulence

The concept of inverse statistics in turbulence has attracted much attention in the recent years. It is argued that the scaling exponents of the direct structure functions and the inverse structure functions satisfy an inversion formula. This proposition has already been verified by numerical data using the shell model. However, no direct evidence was reported for experimental three dimensional turbulence. We propose to test the inversion formula using experimental data of three dimensional fully developed turbulence by considering the energy dissipation rates in stead of the usual efforts on the structure functions. The moments of the exit distances are shown to exhibit nice multifractality. The inversion formula between the direct and inverse exponents is then verified.Comment: 3 RevTex pages including 3 eps figure

Theoretical interpretation of the Ξ(1620)\Xi(1620) and Ξ(1690)\Xi(1690) resonances seen in Ξc+→Ξ−π+π+\Xi_c^+ \to \Xi^- \pi^+ \pi^+ decay

We study the Belle reaction $\Xi_c^+ \to \Xi^- \pi^+ \pi^+$ looking at the mass distribution of $\pi^+ \Xi$, where clear signals for the $\Xi(1620)$ and $\Xi(1690)$ resonances are seen. These two resonances are generated dynamically from the interaction in coupled channels of $\pi \Xi, \bar K \Lambda, \bar K \Sigma$ and $\eta \Xi$ within the chiral unitary approach. Yet, the weak decay process at the quark level, together with the hadronization to produce pairs of mesons, does not produce the $\pi \pi \Xi$ final state. In order to produce this state one must make transitions from the $\bar K \Lambda, \bar K \Sigma$ and $\eta \Xi$ components to $\pi \Xi$, and this interaction is what produces the resonances. So, the reaction offers a good test for the molecular picture of these resonances. Adding the contribution of the $\Xi^*(1530)$ and some background we are able to get a good reproduction of the mass distribution showing the signatures of the two resonances as found in the experiment.Comment: 15 pages, 8 figures, 2 tables; v2: discussion added, references added, version to appear in Eur.Phys.J.

Molecular cloning and expression of a novel trehalose synthase gene from Enterobacter hormaechei

<p>Abstract</p> <p>Background</p> <p>Trehalose synthase (TreS) which converts maltose to trehalose is considered to be a potential biocatalyst for trehalose production. This enzymatic process has the advantage of simple reaction and employs an inexpensive substrate. Therefore, new TreS producing bacteria with suitable enzyme properties are expected to be isolated from extreme environment.</p> <p>Results</p> <p>Six TreS producing strains were isolated from a specimen obtained from soil of the Tibetan Plateau using degenerate PCR. A novel <it>treS </it>gene from <it>Enterobacter hormaechei </it>was amplified using thermal asymmetric interlaced PCR. The gene contained a 1626 bp open reading frame encoding 541 amino acids. The gene was expressed in <it>Escherichia coli</it>, and the recombinant TreS was purified and characterized. The purified TreS had a molecular mass of 65 kDa and an activity of 18.5 U/mg. The optimum temperature and pH for the converting reaction were 37°C and 6, respectively. Hg²⁺, Zn²⁺, Cu²⁺and SDS inhibited the enzyme activity at different levels whereas Mn²⁺showed an enhancing effect by 10%.</p> <p>Conclusion</p> <p>In this study, several TreS producing strains were screened from a source of soil bacteria. The characterization of the recombinant TreS of <it>Enterobacter hormaechei </it>suggested its potential application. Consequently, a strategy for isolation of TreS producing strains and cloning of novel <it>treS </it>genes from natural sources was demonstrated.</p