The Webster scalar curvature problem on the three dimensional CR manifolds

In this paper, we prove some existence results for the Webster scalar curvature problem on the three dimensional CR compact manifolds locally conformally CR equivalent to the unit sphere S³ of C². Our methods are based on the techniques related to the theory of critical points at infinity.     

Isolation and structure determination of a novel furanic ester from the aerial part of Prasium majus

The aerial part of Prasium majus provided a new furanic ester, 2-2-[(5-formyl-6[(5-formylfuran-2-yl)methoxy] succinic acid dimethyl ester, (+/-)-hiziprafuran. Its structure was principally established by one- and two-dimensional NMR spectroscopy.     

Purification and structure elucidation of three naturally bioactive molecules from the new terrestrial Streptomyces sp. TN17 strain

Thirty litres of fermentation broth was extracted from the newly isolated Streptomyces sp. strain TN17 and various separation and purification steps led to the isolation of three pure bioactive compounds (1-3). Compound 1: cyclo (L-Leu-L-Arg), a diketopiperazine 'DKP' derivative; 2: di-(2-ethylhexyl) phthalate, a phthalate derivative; and 3: cyclo 1-[2-(cyclopentanecarbonyl-3-phenyl-propionyl]-pyrrolidine-2-carboxylic acid (1-carbamoyl-propyl)-amide, a cyclic tetrapeptide derivative. The chemical structure of these three active compounds was established on the basis of spectroscopic studies (MS and NMR) and by comparison with data from the literature. According to our biological studies, the pure compounds (1-3) possess antibacterial and antifungal activities.     

Inequalities and Local Uncertainty Principles for Nilpotent Lie Groups

Mathematical Notes - Let $$\mathbb{F}_{q}$$ be a finite field, let $$\mathbb{X}$$ be a subset of the projective space ?s?1 over $$\mathbb{F}_{q}$$ parametrized by rational functions,...     

Self-adjointness of the perturbed wave operator on

We give classes of unbounded real-valued for which is self-adjoint on , , where is the wave operator defined on .

     

Structure-antibacterial activity relationship of secondary metabolites from Ajuga pseudoiva Rob. leaves

A selection of steroids, glycerides, clerodane diterpenoids, and a beta-hydroxy fatty acid methyl ester, all previously isolated from Ajuga pseudoiva leaves, were tested for their antibacterial activity toward three Gram- rods and one Gram+ coccus using the dilution method; MIC values were determined. The results suggested some importance for a free beta-hydroxy group in the fatty acid ester and also in the glycerides and clerodane derivatives; the absolute configurations of the latter, notably at C2, had little influence on activity.     

Heat treatment effects on dielectric and physico-chemical properties of an epoxy polymer

Infrared (IR) spectroscopy, dielectric spectroscopy (DS), and thermally stimulated depolarization current (TSDC) have been used to study heat treatment effects on an epoxy-based polymer. Variations in physico-chemical and dielectric properties were examined for annealing temperatures between 55 and 170 °C. IR results have shown that heating causes both chain scission and thermal oxidation of the polymer, increasing thus the amount of trapped charges. The complex dielectric permittivity and the dielectric modulus have been analyzed, by means of DS, to highlight and separate charge relaxation phenomena from conduction contributions. Results indicate structural rearrangements, leading to a decrease of dipolar relaxation frequency (from 16 to 13.5 kHz) and an increase of the relaxation strength (around 20%). TSDC measurements have shown a current peak shift towards higher temperatures, and a significant intensity decrease, which is proportional to the quantity of released charges.