Effet de la température sur les caractéristiques aérodynamiques de jets chauds turbulents à partir de mesures par Vélocimétrie Laser à Effet Doppler

Les écoulements turbulents chauffés sont d’un grand intérêt dans le domaine aéronautique. Le champ aérodynamique d’un jet libre dont le nombre de Reynolds varie entre 35 000 et 100 000 et la température entre 315 et 460 K a été étudié par Vélocimétrie Laser à effet Doppler. Les résultats montrent entre autres un raccourcissement du cône potentiel et une augmentation des tensions de Reynolds sur l’axe du jet avec la température ainsi qu’une diminution du nombre de Strouhal des instabilités

Early compaction at day 3 may be a useful additional criterion for embryo transfer

PURPOSE: The reduction of the number of embryos transferred while maintaining a satisfactory rate of pregnancy (PR) with in vitro fertilization calls for a refined technique of embryonic selection. This prospective study investigates the significance of early embryonic compaction at day 3 as a marker of the chances of implantation. METHODS: We examined 317 transfers and their outcome involving 509 embryos including 91 compacted embryos. RESULTS: Early compaction seems linked with the ovarian response to stimulation and embryonic quality. The PR is significantly increased when the embryonic cohort contains at least one compacted embryo (44% versus 29.5%, p = 0.01), and when at least one compacted embryo is transferred (44% versus 31%, p < 0.05). The analysis of our single embryo transfers shows that the implantation rates are significantly better for compacted embryos (50% versus 30%, p < 0.05) (OR 2.98; CI 1.02-5.28). CONCLUSION: Thus, early compaction, sometimes observed at day 3, may serve as a useful additional criterion for selecting the embryos transferred

QMPSF is sensitive and specific in the detection of NPHP1 heterozygous deletions

BACKGROUND: Nephronophthisis, an autosomal recessive nephropathy, is responsible for 10% of childhood chronic renal failure. The deletion of its major gene, NPHP1, with a minor allele frequency of 0.24% in the general population, is the most common mutation leading to a monogenic form of childhood chronic renal failure. It is challenging to detect it in the heterozygous state. We aimed to evaluate the sensitivity and the specificity of the quantitative multiplex PCR of short fluorescent fragments (QMPSF) in its detection. METHODS: After setting up the protocol of QMPSF, we validated it on 39 individuals diagnosed by multiplex ligation-dependent probe amplification (MLPA) with normal NPHP1 copy number (n=17), with heterozygous deletion (n=13, seven parents and six patients), or with homozygous deletion (n=9). To assess the rate of the deletions that arise from independent events, deleted alleles were haplotyped. RESULTS: The results of QMPSF and MLPA correlated perfectly in the identification of 76 heterozygously deleted and 56 homozygously deleted exons. The inter-experimental variability of the dosage quotient obtained by QMPSF was low: control, 1.05 (median; range, 0.86-1.33, n = 102 exons); heterozygous deletion, 0.51 (0.42-0.67, n = 76 exons); homozygous deletion, 0 (0-0, n = 56 exons). All patients harboring a heterozygous deletion were found to carry a hemizygous mutation. At least 15 out of 18 deletions appeared on different haplotypes and one deletion appeared de novo. CONCLUSIONS: The cost- and time-effective QMPSF has a 100% sensitivity and specificity in the detection of NPHP1 deletion. The potential de novo appearance of NPHP1 deletions makes its segregation analysis highly recommended in clinical practice

Are zona pellucida genes involved in recurrent oocyte lysis observed during in vitro fertilization?

PURPOSE: Complete oocyte lysis in in vitro fertilization (IVF) is a rare event, but one against which we remain helpless. The recurrence of this phenomenon in some women in each of their IVF attempts, regardless of treatment, together with the results of animal experiments led us to investigate the possible involvement of the genes encoding for the glycoproteins constituting the zona pellucida (ZP). PATIENTS & METHODS: Over the last ten years, during which we treated over 500 women each year, three women suffered recurrent oocyte lysis during their IVF attempts in our Centre for Reproductive Biology. For each of these three cases, we sequenced the four genes and promoter sequences encoding the glycoproteins of the ZP. The sequence variations likely to cause a change in protein expression or structure, were investigated in a control group of 35 women who underwent IVF without oocyte lysis and with normal rates of fertilization. RESULTS & CONCLUSION: We found no mutations in the ZP genes sequenced. Only some polymorphisms present in the control group and in the general population were detected, excluding their specific involvement in the phenotype observed. Thus, although we suspected that complete oocyte lysis was due to a genetic cause, it did not seem possible to directly incriminate the genes encoding the proteins of the ZP in the observed phenotype. Further study of the genes involved in the processing and organization of ZP glycoproteins may allow elucidation of the mechanism underlying recurrent oocyte lysis during in vitro fertilization

Molecular characterization of corona radiata cells from patients with diminished ovarian reserve using microarray and microfluidic-based gene expression profiling

BACKGROUND: Diminished ovarian reserve (DOR) is one of the causes of infertility in young women. In this prospective study, gene expression profiling (GEP) of corona radiata cells (CRC) was performed to identify genes deregulated in DOR patients. METHODS: Microarray-based GEP of CRC isolated from eight women undergoing IVF was performed to identify genes differentially expressed between patients with normal ovarian reserve and DOR patients. Microfluidic-based quantitative RT-PCR assays were used to validate selected transcripts on 40 independent patients. A principal component analysis was used to identify more homogeneous subgroups of DOR patients. In silico analyses focusing on cis-regulation were performed to refine the interactions between patient\u27s biological characteristics and their GEP. RESULTS: Forty-eight transcripts were differentially expressed, including CXXC finger protein 5 (CXXC5), forkhead box C1 (FOXC1) (down-regulated in DOR) as well as connective tissue growth factor (CTGF), follistatin-like 3 (FSTL3), prostaglandin-endoperoxide synthase 2 (PTGS2) and suppressor of cytokine signaling 2 (SOCS2) (up-regulated in DOR). According to these transcripts, two DOR patients\u27 subgroups (DOR Gr1 and Gr2) were identified. In DOR Gr2 patients, C-terminal domain 2 (CITED2), CTGF, growth arrest-specific 1 (GAS1), insulin receptor substrate 2 (IRS2), PTGS2, SOCS2 and Versican (VCAN) were expressed at significantly higher levels and CXXC5, FOXC1, guanylate-binding protein 2 (GBP2) and zinc finger MIZ-domain containing 1 (ZMIZ1) at significantly lower levels. Higher baseline estradiol (E(2)) levels were observed in DOR Gr2 patients (P < 0.006). The in silico analyses suggested that all 11 genes differentially expressed between DOR Gr1 and DOR Gr2 subgroups could be transcriptional targets of estrogen. CONCLUSIONS: Despite small sample size limitations, 12 genes deregulated in the CRC of DOR patients were identified, which could be involved in DOR pathogenesis. A DOR patient\u27s subgroup with high baseline E(2) levels and deregulated estrogen-responsive genes was also identified

Physico-chemical and biological characterization of an aquifer polluted with ETBE

International audiencePetroleum compounds and among them, gasoline, is the most massively used chemicals worldwide and, as a consequence gasoline derives compounds are the most frequently found contaminants in groundwate