Functional renormalization group study of the Nambu--Jona-Lasinio model at finite temperature and density in an external magnetic field

In this study, we investigate the Nambu--Jona-Lasinio (NJL) model at finite temperature and finite density in an external magnetic field using the functional renormalization group. We investigate the dependence of the position of the ultraviolet fixed point (UVFP) of the four-Fermi coupling constant on the temperature, density, and external magnetic field, and we obtain the chiral phase structure. The UVFP at low temperature and finite chemical potential oscillates in a small external magnetic field, which can be interpreted as the de Haas--van Alphen effect. We also obtain phase diagrams with complex structures, where the phase boundary moves back and forth as the external magnetic field increases in the low temperature and high density region.Comment: 6 pages, 6 figures, published versio

Phase structure of NJL model with weak renormalization group

We analyze the chiral phase structure of the Nambu--Jona-Lasinio model at finite temperature and density by using the functional renormalization group (FRG). The renormalization group (RG) equation for the fermionic effective potential $V(\sigma;t)$ is given as a partial differential equation, where $\sigma:=\bar \psi\psi$ and $t$ is a dimensionless RG scale. When the dynamical chiral symmetry breaking (D$\chi$SB) occurs at a certain scale $t_c$, $V(\sigma;t)$ has singularities originated from the phase transitions, and then one cannot follow RG flows after $t_c$. In this study, we introduce the weak solution method to the RG equation in order to follow the RG flows after the D$\chi$SB and to evaluate the dynamical mass and the chiral condensate in low energy scales. It is shown that the weak solution of the RG equation correctly captures vacuum structures and critical phenomena within the pure fermionic system. We show the chiral phase diagram on temperature, chemical potential and the four-Fermi coupling constant.Comment: 32 pages, 12 figures; Version published in Nuclear Physics

Evaluation of quantum chemistry calculation methods for conformational analysis of organic molecules using A-value estimation as a benchmark test

A-values of 20 substituents were estimated by quantum chemistry calculations of different theoretical levels. Comparison with the reported experimental values provided a good benchmark to evaluate the theoretical levels for the conformational analysis of organic molecules

Cloning and Expression of a Perilla frutescens Cytochrome P450 Enzyme Catalyzing the Hydroxylation of Phenylpropenes

Phenylpropanoid volatile components in plants are useful and valuable not only as flavorings, but also as medicines and food supplements. The pharmacological actions and toxicities of these compounds have been well studied but their synthetic pathways are generally unclear. In this study, we mined expressed sequence tag libraries of pure strains of perilla maintained for over 30 years for their oil type and conducted gas chromatography-mass spectrometry analyses of the perilla oils to confirm the presence of monohydrates speculated to be intermediates of the phenylpropene synthetics pathways. These putative monohydrate intermediates and their regioisomers were synthesized to identify the reaction products of assays of heterologously expressed enzymes. An enzyme involved in the synthesis of a phenylpropanoid volatile component was identified in perilla. Expression of this enzyme in Saccharomyces cerevisiae showed that it is a member of the cytochrome P450 family and catalyzes the introduction of a hydroxy group onto myristicin to form an intermediate of dillapiole. The enzyme had high sequence similarity to a CYP71D family enzyme, high regiospecificity, and low substrate specificity. This study may aid the elucidation of generally unexploited biosynthetic pathways of phenylpropanoid volatile components

Preparation of N-2-Nitrophenylsulfenyl Imino Peptides and Their Catalyst-Controlled Diastereoselective Indolylation

N-2-Nitrophenylsulfenyl (Nps) imino dipeptides bearing various functional groups were successfully prepared via MnO2-mediated oxidation and then subjected to diastereoselective indolylation. Each diastereomer of the adduct was selectively obtained from the same substrates using the appropriate chiral phosphoric acid catalysts. These transformations would be useful for synthesizing non-canonical amino acid-containing peptides as novel drug candidates