175 research outputs found

    The influence of phosphorus content on magnetic anisotropy in ferromagnetic (Ga, Mn) (As, P)/GaAs thin films

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    International audienceThe magnetic anisotropy of the ferromagnetic semiconductor (Ga, Mn) (As, P) is studied in a material-specific microscopic k . p approach. We calculate the electronic energy band structure of (Ga, Mn) (As, P) quaternary ferromagnetic alloys using a 40-band k . p model and taking into account the s, p-d exchange interaction and the strain of the (Ga, Mn) (As, P) layer on a GaAs substrate. We determine the variations of the carrier effective masses in the strained (Ga, Mn) (As, P)/GaAs system. The magnetic anisotropy constants obtained from our simulations using a mean-field model are compared with the experimental ones determined by ferromagnetic resonance spectroscopy on a set of samples with constant manganese concentration and varying phosphorus concentration. An excellent quantitative agreement between experiment and theory is found for the uniaxial out-of-plane and cubic in-plane anisotropy parameters

    Evaluation of the impact of wastewater in the rural commune of Jmaa Moulblad on the bacteriological water quality of the Grou River (Rabat region, Morocco)

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    In the region of Rabat, shallow watercourses are currently threatened by the magnitude of urban and industrial discharges, mainly due to its growing demography and the continuous development of the agricultural and industrial sectors. This study aims to evaluate the impact of wastewater from the rural commune of Jmaa Moulblad on the bacteriological water qualityof the Grou River. In order to measure the pollution levels of this watercourse, our study focused on the enumeration of fecal contamination indicator bacteria such as total coliforms (TC), faecal coliforms (FC) and intestinal enterococci (EI), as well as the detection of salmonella. Water samples were taken by season during the 2016/2017 period at four stations on the Grou River. The results obtained describe a worrying state of the watercourse, particularly at the S2 station located directly at the mouth of the wastewater of the rural commune of Jmaa Moulblad which is rejected without prior treatment. If protective measures are not taken, the perpetual degradation of the quality of these waters would certainly lead to the loss of this watercourse, which is of paramount importance in the region.

    Improved flux limits for neutrinos with energies above 1022^{22} eV from observations with the Westerbork Synthesis Radio Telescope

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    Particle cascades initiated by ultra-high energy (UHE) neutrinos in the lunar regolith will emit an electromagnetic pulse with a time duration of the order of nano seconds through a process known as the Askaryan effect. It has been shown that in an observing window around 150 MHz there is a maximum chance for detecting this radiation with radio telescopes commonly used in astronomy. In 50 hours of observation time with the Westerbork Synthesis Radio Telescope array we have set a new limit on the flux of neutrinos, summed over all flavors, with energies in excess of 4×10224\times10^{22} eV.Comment: Submitted to Phys. Rev. Let

    Two highly divergent alcohol dehydrogenases of melon exhibit fruit ripening-specific expression and distinct biochemical characteristics

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    Alcohol dehydrogenases (ADH) participate in the biosynthetic pathway of aroma volatiles in fruit by interconverting aldehydes to alcohols and providing substrates for the formation of esters. Two highly divergent ADH genes (15% identity at the amino acid level) of Cantaloupe Charentais melon (Cucumis melo var. Cantalupensis) have been isolated. Cm-ADH1 belongs to the medium-chain zinc-binding type of ADHs and is highly similar to all ADH genes expressed in fruit isolated so far. Cm-ADH2 belongs to the short-chain type of ADHs. The two encoded proteins are enzymatically active upon expression in yeast. Cm-ADH1 has strong preference for NAPDH as a co-factor, whereas Cm-ADH2 preferentially uses NADH. Both Cm-ADH proteins are much more active as reductases with Kms 10–20 times lower for the conversion of aldehydes to alcohols than for the dehydrogenation of alcohols to aldehydes. They both show strong preference for aliphatic aldehydes but Cm-ADH1 is capable of reducing branched aldehydes such as 3-methylbutyraldehyde, whereas Cm-ADH2 cannot. Both Cm-ADH genes are expressed specifically in fruit and up-regulated during ripening. Gene expression as well as total ADH activity are strongly inhibited in antisense ACC oxidase melons and in melon fruit treated with the ethylene antagonist 1-methylcyclopropene (1-MCP), indicating a positive regulation by ethylene. These data suggest that each of the Cm-ADH protein plays a specific role in the regulation of aroma biosynthesis in melon fruit

    Investigating the Biological Activities of Moroccan Cannabis Sativa L Seed Extracts: Antimicrobial, Anti-inflammatory, and Antioxidant Effects with Molecular Docking Analysis

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    The present study focuses on assessing the bioactive potential of Cannabis sativa L. seed extracts, specifically the organic and aqueous extracts derived from Ketama hemp seeds harvested in Morocco. We tested the antioxidant capacities of the extracts, specifically their ability to scavenge DPPH free radicals. The ethanolic Cannabis sativa L. seed extract was particularly effective, demonstrating the lowest IC50 value of 0.36mg/mL±0.01, outperforming the reference compound ascorbic acid, which had an IC50 value of 0.68mg/mL±0.02. This suggests a significantly high antioxidant potential of the ethanolic extract against the DPPH radical. The β-carotene bleaching test further supported these findings, with the ethanolic and hexanolic extracts showing substantial antioxidant activity, inhibiting the coupled oxidation of linoleic acid and β-carotene by 36%±0.12 and 33%±0.14, respectively. We also assessed the antimicrobial potency of the seed extracts using the Muller-Hinton Agar well diffusion method. The ethanolic extract demonstrated the highest inhibition zone diameter (IZ = 23 mm) against Penicillium sp., whereas the hexane extract had the smallest IZ (07 mm) against Listeria monocytogenes. Microdilution method in a 96-well microplate was employed to determine the minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC), and minimum fungicidal concentration (MFC) of the extracts. All extracts showed inhibitory effects against all tested bacterial and fungal strains, with MIC, MBC, and MFC values ranging from 0.03 to 1.25 mg/mL. Lastly, the anti-inflammatory activity of the extracts was tested using the RBC method. The findings indicated that all extracts significantly inhibited heat/hypotonia-induced erythrocyte haemolysis, further exploring their potential therapeutic value

    The use of pentaploid crosses for the introgression of Amblyopyrum muticum and D-genome chromosome segments into durum wheat

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    The wild relatives of wheat provide an important source of genetic variation for wheat improvement. Much of the work in the past aimed at transferring genetic variation from wild relatives into wheat has relied on the exploitation of the ph1b mutant, located on the long arm of chromosome 5B. This mutation allows homoeologous recombination to occur between chromosomes from related but different genomes, e.g. between the chromosomes of wheat and related chromosomes from a wild relative resulting in the generation of interspecific recombinant chromosomes. However, the ph1b mutant also enables recombination to occur between the homoeologous genomes of wheat, e.g. A/B, A/D, B/D, resulting in the generation of wheat intergenomic recombinant chromosomes. In this work we report on the presence of wheat intergenomic recombinants in the genomic background of hexaploid wheat/Amblyopyrum muticum introgression lines. The transfer of genomic rearrangements involving the D-genome through pentaploid crosses provides a strategy by which the D-genome of wheat can be introgressed into durum wheat. Hence, a pentaploid crossing strategy was used to transfer D-genome segments, translocated with either the A- and/or the B-genome, into the tetraploid background of two durum wheat genotypes Karim and Om Rabi 5 in either the presence or absence of different Am. muticum (2n = 2x = 14, TT) segments. Translocations were monitored in backcross generations to the durum wheat parents via multicolour genomic in situ hybridisation (mc-GISH). Tetraploid lines carrying homozygous D-genome introgressions, as well as simultaneous homozygous D- and T-genome introgressions, were developed. Introgression lines were characterised via KASP markers and multicolour fluorescence in situ hybridisation (FISH). Results showed that new wheat sub-genomic translocations were generated at each generation in progeny that carried any Am. muticum chromosome segment irrespective of the linkage group that the segment was derived from. The highest frequencies of homoeologous recombination were observed between the A- and the D-genomes. Results indicated that the genotype Karim had a higher tolerance to genomic rearrangements and T-genome introgressions compared to Om Rabi 5. This indicates the importance of the selection of the parental genotype when attempting to transfer/develop introgressions into durum wheat from pentaploid crosses
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