Bertrand curves of AW(k)-type in Lorentzian space

In this study, firstly, we give curvature conditions of AW(k)-type (1≤k≤3$1\le k\le 3$) curves. Then considering AW(k)-type curves, we investigate Bertrand curves γ:I→L³$\gamma :I\to L^3$ with _κ1(s)≠0${\kappa }_1\left(s\right)\ne 0$ and _κ2(s)≠0${\kappa }_2\left(s\right)\ne 0$. We show that there are Bertrand curves of AW(1)-type and AW(3)-type. Moreover, we study weak AW(2)-type and AW(3)-type conical geodesic curves in L³$L^3$.     

Study of the stability of the fermionic instanton solutions by the scale index method

In the last years, there has been great interest to the formulation and application of wavelet transformation in variety of fields to investigate the characteristics of dynamical systems. Recently, a method based on the scalogram analysis of the continuous wavelet transform, the scale index has been proposed to measure aperiodicity and determine the transitions from aperiodic behaviour to periodic behaviour in nonlinear dynamical systems. In this work we test the scale index method by performing the analysis of the deterministic behaviour of the fermion-like two-dimensional Akdeniz–Smailagic instanton solution in Thirring Model. We show that the scale index method can also be considered to detect the periodic behaviours of the fermion-like instanton solutions.     

In Vitro Inhibition Effect of Some Dihydroxy Coumarin Compounds on Purified Human Serum Paraoxonase 1 (PON1)

Human serum paraoxonase 1 (PON1; EC 3.1.8.1) is a high-density lipoprotein associated, calcium-dependent enzyme that hydrolyses aromatic esters, organophosphates and lactones and can protect the low-density lipoprotein against oxidation. In this study, in vitro inhibition effect of some dihydroxy coumarin compounds namely 6,7-dihydroxy-3-(2-methylphenyl)-2H-chromen-2-one (A), 6,7-dihydroxy-3-(3-methylphenyl)-2H-chromen-2-one (B) and 6,7-dihydroxy-3-(4-methylphenyl)-2H-chromen-2-one (C) on purified PON1 were investigated by using paraoxon as a substrate. PON1 was purified using two-step procedures, namely ammonium sulphate precipitation and Sepharose-4B-l-tyrosine-1-naphthylamine hydrophobic interaction chromatography. The purified enzyme had a specific activity of 11.76?U/mg. The dihydroxy coumarin derivatives of A and B compounds inhibited PON1 enzyme activity in a noncompetitive inhibition manner with K _i of 0.0080?±?0.256 and 0.0003?±?0.018?mM values, respectively. C compound exerted an uncompetitive inhibition of PON1 enzyme activity with K _i of 0.0010?±?0.173?mM. Moreover, dihydroxy coumarin derivatives of A, B and C compounds were effective inhibitors on purified human serum PON1 activity with IC₅₀ of 0.012, 0.022 and 0.003?mM values, respectively. IC₅₀ value of unsubstituted 6,7 dihydroxy coumarin was found as 0.178?mM. The present study has demonstrated that PON1 activity is very highly sensitive to studied coumarin derivatives.     

Tetraphenylporphyrins monosubstituted with glycerol derivative units in the phenyl rings. Synthesis and characterization

Summary The synthesis and spectroscopic characterization of a series ofmeso-tetraphenyl substituted porphyrins appended with glycerol, diacetylglycerol, or isopropylideneglycerol units inortho,meta, orpara position of the phenylene ring is described.

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Synthese und Charakterisierung von an den Phenylresten mit Glycerinderivaten monosubstituierten Tetraphenylporphyrinen

Zusammenfassung Synthese und spektroskopische Charakterisierung einer Reihe von an den Phenylringen inortho-,meta- oderpara-Position mit Glycerin, Diacetylglycerin oder Isopropylidenglycerin substituiertenmeso-tetraphenylsubstituierten Porphyrinen wird beschrieben.

     

Microwave Assisted Synthesis of Chitosan Nanoparticles

Chitosan nanoparticles (CHN) were prepared based on ionotropic gelation between low moleculer weight chitosan and sodium tripolyphosphate (TPP) under microwave irradiation. Particle size, zeta potential, and FT-IR techniques were used for characterization of CHN. The influence of reaction time on the nanoparticle size distribution was investigated, and the results showed that the microwave irradiation method evidently decreases the reaction times and particle size over the conventional method. It was determined by the results of the zeta potential measurements that synthesized CHN under microwave irradiation clearly exhibits more homogeneous and stable dispersion.