Search

The principal objective of the present study is to evaluate both the chemical composition and antibacterial effectiveness of essential oil of Clinopodium nepeta subs ascendens (CNEO) against three Gram-positive bacteria (Staphylococcus aureus, Micrococcus luteus, and Bacillus subtilis) and three Gram-negative bacteria (Escherichia coli, Pseudomonas aeruginosa, and Klebsiella pneumoniae). Additionally, this research aims to explore potential synergies between CNEO and established antibiotics. The phytochemical composition of CNEO was thoroughly examined via gas chromatography mass spectrometry (GC-MS), revealing neoisomenthol (37.89%), pulegone (20.11%), and dihydrocarvone (19.01%) as the primary bioactive molecules. CNEO exhibited substantial antibacterial activity, with minimum inhibitory concentration (MIC) values ranging from 0.10 against E. coli to 1 mg/mL against K. pneumoniae. This promising antimicrobial activity, especially noteworthy against antibiotic-resistant bacteria, prompted an evaluation of CNEO's synergistic potential with antibiotics using the Fractional Inhibitory Concentration Index (FICI). The FICI analysis, especially with ampicillin against P. aeruginosa, uncovered an optimal synergistic interaction at a FICI of 0.31. Notably, observed reductions in MIC values for CNEO and antibiotics, ranging from 2-7 folds, highlight the heightened efficacy of these combinations. These findings hold significance for developing new approaches to address the increasing challenges of bacterial infections resistant to conventional treatments. [ABSTRACT FROM AUTHOR]

In sheep, the woolly or hairy fleece type shows variation within and between breeds and populations. Recently, the woolly allele was shown to result from the insertion of an antisens retrogene into the 3'UTR of the ovine IRF2BP2 gene. The purpose of this study was to examine this InDel polymorphism within the IRF2BP2 gene using a specific PCR genotyping in 17 North African (Algeria and Tunisia) and Iranian sheep breeds showing various fleece types. The genotyping of the overall animals (n=908) showed the segregation of the two alleles insertion (I) and deletion (D), and the three genotypes (II, ID and DD) with various frequencies. Ouled Djellal, Rembi and Tâadmit known as woolly breeds had 100%, 94% and 94% of II homozygous animals, respectively. In contrast, Ifilène and Sidaou known as hairy breeds had 100% and 99% of DD homozygous animals. Other breeds showed the segregation of the I allele with a frequency from 3% to 91%. An association analysis, carried out only for the Algerian sheep breeds, revealed that this polymorphism was significantly associated with the fleece type trait (P<0.05). Thus, the current work meets previous results to further confirm the genetic effect of the insertion occurring into the 3' UTR of the IRF2BP2 gene on the fleece type trait of sheep breeds. [ABSTRACT FROM AUTHOR]

We perform a theoretical study of the optical transitions for different excitonic complexes in highly symmetric strain-free GaAs quantum dots (QDs) fabricated by epitaxially filling nanoholes (NHs) in an AlGaAs surface. NHs are formed by local droplet etching. As a first step, we propose a QD shape modeling consistent with atomic force microscopy (AFM) profiles and an experimental growth procedure. We investigate the QD height dependence of s- and p- shell exciton recombination energies in the framework of the effective mass approximation with an exact numerical diagonalization method. A comparison between theoretical results and available spectroscopic data is carried out. Systematic evolution of the binding energies of neutral (X), charged excitons (X-, X+) and the biexciton (XX), with QD height, is interpreted in terms of a balance between the Coulomb interactions and charge carrier correlation effects. Our calculations demonstrate the important role of the correlation energies in elucidating the bound character of all few-particle states especially the biexciton. [ABSTRACT FROM AUTHOR]

Optical properties of Yb-doped LiNbO3 crystals were investigated. The low temperature absorption and selective emission of LiNbO3:Yb3+ crystals obtained by Montoya et al were reexamined. The LiNbO3:Yb3+ crystals absorption and emission spectra show broad emission due to the presence of four non-equivalent sites: three octahedral sites (Li+ (S1), Nb5+(S2), and a vacant octahedron(S3)) and an interstitial tetrahedral site(S4). Considering the presence of these four Yb3+ion-occupied sites, and also the electron-phonon coupling processes, the majority of emission and absorption lines was assigned. For the different observed optical centers in LiNbO3, the experimental Stark energy levels of Yb3+ ions were established. [ABSTRACT FROM AUTHOR]