High enthalpy source dedicated to quantitative infrared emission spectroscopy of gas flows at elevated temperatures.

The High Enthalpy Source (HES) is a novel high temperature source developed to measure infrared line-by-line integrated absorption cross sections of flowing gases up to 2000 K. The HES relies on a porous graphite furnace designed to uniformly heat a constant flow of gas. The flow compensates thermal dissociation by renewing continuously the gas sample and eliminating dissociation products. The flowing characteristics have been investigated using computational fluid dynamics simulation confirming good temperature uniformity. The HES has been coupled to a high-resolution Fourier transform spectrometer to record emission spectra of methane at temperatures ranging between 700 and 1400 K. A radiative model has been developed to extract absolute line intensities from the recorded spectra.

A mass-selective ion transfer line coupled with a uniform supersonic flow for studying ion-molecule reactions at low temperatures.

A new approach based on the uniform supersonic flow technique-a cold, thermalized de Laval expansion offering the advantage of performing experiments with condensable species-has been developed to study ion-molecule reactions at low temperatures. It employs a mass-selective radio frequency transfer line to capture and select ions from an adaptable ionization source and to inject the selected ions in the core of the supersonic expansion where rate coefficients and product branching can be measured from room temperature down to ∼15 K. The transfer line incorporates segmented ion guides combining quadrupolar and octapolar field orders to maximize transmission through the differential apertures and the large pressure gradients encountered between the ionization source (∼mbar), the quadrupole mass filter (∼10-5 mbar), and the de Laval expansion (∼mbar). All components were designed to enable the injection of cations and anions of virtually any m/z ratio up to 200 at near ground potential, allowing for a precise control over the momentum and thermalization of the ions in the flow. The kinetics and branching ratios of a selection of reactions have been examined to validate the approach. The technique will be instrumental in providing new insight on the reactivity of polyatomic ions and molecular cluster ions in astrophysical and planetary environments.

Socioeconomic inequalities in weight, height and body mass index from birth to 5 years.

BACKGROUND/OBJECTIVES: Studies in high-income countries show that despite the positive association of weight with socioeconomic position at birth, an inverse socioeconomic gradient in overweight (OW) appears later in childhood. The objectives were to understand the natural history of socioeconomic inequalities in weight, height and body mass index (BMI), by investigating their associations with maternal educational level between birth and 5 years, separately in boys and girls. SUBJECTS/METHODS: A published work of growth modelling between birth and 5 years allowed us to calculate predicted weight, height and BMI at 1 month, 6 months, 1, 3 and 5 years for 1735 children from the French EDEN mother-child cohort. Associations between maternal education and predicted measures of body size were analysed with marginal linear and logistic models, stratified by sex. RESULTS: In girls, despite a positive association between maternal education and birthweight, an inverse socioeconomic gradient was observed as early as 1 month for BMI. Girls whose mothers had low education levels were shorter on the whole than their counterparts with better-educated mothers, despite their similar weights. In boys, no socioeconomic gradient in BMI was observed at any age, including birth, but positive associations were found as early as 1 month for both weight and height. CONCLUSIONS: The emergence of an inverse socioeconomic gradient in BMI and OW apparently results from a complex pattern of socioeconomic inequalities in weight and height from 1 month onwards. The very start of life thus appears to be an important window of opportunity for addressing socioeconomic inequalities in growth.

Influence of infant feeding patterns over the first year of life on growth from birth to 5 years.

OBJECTIVES: As early-life feeding experiences may influence later health, we aimed to examine relations between feeding patterns over the first year of life and child's growth in the first 5 years of life. METHODS: Our analysis included 1022 children from the EDEN mother-child cohort. Three feeding patterns were previously identified, i.e. 'Later dairy products introduction and use of ready-prepared baby foods' (pattern-1), 'Long breastfeeding, later main meal food introduction and use of home-made foods' (pattern-2) and 'Use of ready-prepared adult foods' (pattern-3). Associations between the feeding patterns and growth [weight, height and body mass index {BMI}] were analysed by multivariable linear regressions. Anthropometric changes were assessed by the final value adjusted for the initial value. RESULTS: Even though infant feeding patterns were not related to anthropometric measurements at 1, 3 and 5 years, high scores on pattern-1 were associated with higher 1-3 years weight and height changes. High scores on pattern-2 were related to lower 0-1 year weight and height changes, higher 1-5 years weight and height changes but not to BMI changes, after controlling for a wide range of potential confounding variables including parental BMI. Scores on pattern-3 were not significantly related to growth. Additional adjustment for breastfeeding duration reduced the strength of the associations between pattern-2 and growth but not those between pattern-1 and height growth. CONCLUSION: Our findings emphasize the relevance of considering infant feeding patterns including breastfeeding duration, age of complementary foods introduction as well as type of foods used when examining effects of early infant feeding practices on later health. © 2017 World Obesity Federation.

Prospective associations between energy balance-related behaviors at 2 years of age and subsequent adiposity: the EDEN mother-child cohort.

BACKGROUND/OBJECTIVES: Sedentary behavior, physical activity and dietary behavior are formed early during childhood and tend to remain relatively stable into later life. No longitudinal studies have assessed the independent influence of these three energy balance-related behaviors during toddlerhood on later adiposity. We aimed to analyze the associations between TV/DVD watching time, outdoor play time and dietary patterns at the age of 2 years and child adiposity at the age of 5 years, in boys and girls separately. SUBJECTS/METHODS: This study included 883 children from the French EDEN mother-child cohort. TV/DVD watching time, outdoor play time and dietary intakes were reported by parents in questionnaires when the child was aged 2 years. Two dietary patterns, labeled 'Guidelines' and 'Processed, fast foods', were identified in a previous study. The percentage of body fat (%BF) based on bioelectrical impedance analysis and body mass index were measured at the age of 5 years. RESULTS: In boys, TV/DVD watching time at the age of 2 years was positively associated with %BF at the age of 5 years (ß=0.50 (95% confidence interval: 0.001, 1.00) for those boys with ⩾60 min per day of TV/DVD watching time vs those with ⩽15 min per day, P-value for trend 0.05). In girls, outdoor play was inversely associated with %BF (ß=-0.96 (95% confidence interval: -1.60, -0.32) for those in the highest tertile of outdoor play time vs those in the lowest tertile, P=0.001). Overall, at the age of 2 years, dietary patterns were associated with both TV/DVD watching time and outdoor play time, but no significant and independent association was observed between dietary patterns and later adiposity. CONCLUSION: This study shows longitudinal and gender-differentiated relations between both TV/DVD watching time and outdoor play time in toddlerhood and later adiposity, whereas evidence for a relation between dietary patterns and subsequent fat development was less conclusive. Early childhood-by the age of 2 years-should be targeted as a critical time for promoting healthy energy balance-related behaviors.

Electron and ion reactions with hexamethyldisiloxane and pentamethyldisiloxane.

The dissociative recombination of electrons with the hexamethyldisiloxane (HMDSO) cation ((CH(3))(3)Si-O-Si(CH(3))(3))(+) and the pentamethyldisiloxane cation ((CH(3))(3)Si-O-Si(CH(2))(2))(+) as well as the ion-molecule reaction between Ar(+) and HMDSO have been studied at 300 K using a flowing afterglow Langmuir probe-mass spectrometer apparatus. The rate constants for these reactions, measured directly for the first time, are, respectively, alpha(1)=1.8 x 10(-6), alpha(2)=3.6 x 10(-6) cm(3)s, and k=2.0 x 10(-9) cm(3)s with uncertainties of +/-30%. In addition, the electronic attachment to neutral HMDSO was also studied and an upper limit value of the rate constant was determined to be beta=3.3 x 10(-11) cm(3)s.

Electron attachment on HI and DI in a uniform supersonic flow: thermalization of the electrons.

In order to check the electron thermalization in the CRESU technique (Cinetique de Reaction en Ecoulement Supersonique Uniforme, e.g., "reaction kinetics in a uniform supersonic flow"), electron attachment on HI and DI has been studied in the 48-170 K range. Attachment to HI is exothermic and the reaction is expected to be fast and to proceed at a rate close to the capture limit. On the contrary, attachment to DI is slightly endothermic, and a strong positive temperature dependence of the measured rate coefficient is expected if the electrons are thermal. This dependence is not observed, and we conclude that the electrons are not in thermal equilibrium with the neutrals in the afterglow. A model, based on electron heating by superelastic collisions with the buffer gas, is proposed to explain this fact and implications for previously published results are discussed.

A new approach for identifying non-pathogenic mutations. An analysis of the cystic fibrosis transmembrane regulator gene in normal individuals.

Given q as the global frequency of the alleles causing a disease, any allele with a frequency higher than q minus the cumulative frequency of the previously known disease-causing mutations (threshold) cannot be the cause of that disease. This principle was applied to the analysis of cystic fibrosis transmembrane conductance regulator (CFTR) mutations in order to decide whether they are the cause of cystic fibrosis. A total of 191 DNA samples from random individuals from Italy, France, and Spain were investigated by DGGE (denaturing gradient gel electrophoresis) analysis of all the coding and proximal non-coding regions of the gene. The mutations detected by DGGE were identified by sequencing. The sample size was sufficient to select essentially all mutations with a frequency of at least 0.01. A total of 46 mutations was detected, 20 of which were missense mutations. Four new mutations were identified: 1341+28 C/T, 2082 C/T, L1096R, and I11131V. Thirteen mutations (125 G/C, 875+40 A/G, TTGAn, IVS8-6 5T, IVS8-6 9T, 1525-61 A/G, M470V, 2694 T/G, 3061-65 C/A, 4002 A/G, 4521 G/A, IVS8 TG10, IVS8 TG12) were classified as non-CF-causing alleles on the basis of their frequency. The remaining mutations have a cumulative frequency far exceeding q; therefore, most of them cannot be CF-causing mutations. This is the first random survey capable of detecting all the polymorphisms of the coding sequence of a gene.

Complete mutational screening of the cystic fibrosis transmembrane conductance regulator gene: cystic fibrosis mutations are not involved in healthy men with reduced sperm quality.

Based on the analysis of the most frequent mutations responsible for cystic fibrosis (CF), a higher than expected frequency of CF mutations was recently reported in men with infertility due to reduced sperm quality. To further document whether this condition is associated with severe or mild abnormalities of cystic fibrosis transmembrane conductance regulator (CFTR) functions, we carried out a complete scanning of CFTR sequences using a strategy that detects almost all 850 mutations and 150 polymorphisms reported to date in the CFTR gene. We have investigated a cohort of 56 patients with severe oligoasthenoteratozoospermia (OAT) and 50 controls from southern France for CFTR gene mutations and variations. The frequencies of CF-causing mutations and CFTR variations identified in this OAT sample did not differ significantly from the frequencies found in the normal population. However, we observed a 1.7-fold increase in the proportion of homozygotes for a specific CFTR haplotype (TG11-T7-G1540) in the OAT group (P = 0.025). Our results do not confirm a link between CF mutations and reduced sperm quality. Further studies are needed to substantiate the hypothesis that a combination of variants affecting expression and function of the CFTR protein is associated with male infertility.

Linkage disequilibrium between the M470V variant and the IVS8 polyT alleles of the CFTR gene in CBAVD.

Congenital bilateral absence of the vas deferens (CBAVD) is a cause of male sterility mostly resulting from mutations in the cystic fibrosis transmembrane regulator (CFTR) gene. The most common defect is the 5T variant at the branch/acceptor site of intron 8, which induces high levels of exon 9 skipping leading to non-functional protein. However, this 5T variant has incomplete penetrance and variable expressivity, suggesting that some other regulatory factors may modulate the splicing of exon 9. To identify such factors, we report here the genetic analysis of a polymorphic locus, M470V, located in exon 10 of the CFTR gene in 60 patients with CBAVD, compared to a normal control population. The statistical analysis showed strong linkage disequilibrium between the 5T allele and the V allele of the M470V polymorphism in the CBAVD population, but not in the normal population. The V allele in a gene carrying 5T could, however, contribute to lowering the level of normal transcripts, as already suggested by in vitro transcriptional studies. These genetic findings, together with previous studies, suggest involvement of the M470V variant in the modulation of the splicing of exon 9 of the CFTR gene.

Genetic findings in congenital bilateral aplasia of vas deferens patients and identification of six novel mutatations. Mutations in brief no. 138. Online.

Congential bilateral aplasia of vas deferens (CBAVD), a form of male sterility, has been suggested to represent a "genital" form of cystic fibrosis (CF), as mutations in the CFTR gene have been identified in most patients with this condition. Interestingly, the 5T allele in intron 8 appeared to be the most frequent mutation associated with CBAVD. However, the molecular basis of CBAVD is not completely understood. We have analysed the complete coding and flanking CFTR sequences by PCR-DGGE in 64 men with CBAVD from southern France with the aim to list any sequence alteration. Fourty-two of the 64 patients (65.6%) had mutations on both copies of the CFTR gene, including one patient with two mutations in the same copy (DF508 + A1067T). The 5T allele was present in 21/64 cases (33%). Six of the 28 different mutations identified in this study had never been described previously, and appeared to be specific to CBAVD (P111L, M244K, A1364V, G544V, 2896insAG,-33G->A).

Cystic fibrosis in Lebanon: distribution of CFTR mutations among Arab communities.

Cystic fibrosis (CF) is thought to be rare among the Arab populations from the Middle East and little data have been reported so far. We have studied a sample of 20 families living in Lebanon for several generations and who have at least one child with CF. These families are mainly from the Maronite, Greek Catholic, Greek Orthodox. Shiite or Sunnite groups. We found a 50% rate of consanguineous marriage, independent of the community of origin. The distribution of CF genotypes was determined through the screening of all exons of the CFTR (cystic fibrosis transmembrane conductance regulator) gene by the technique of denaturing gradient gel electrophoresis combined with asymmetric amplification DNA sequencing. A total of ten different mutations accounting for 87.5% of 32 unrelated CF alleles was identified, including two novel putative mutations (E672del and IVS21-28G-->A). Three mutations, delta F508 (37.5%), W1282X (15.6%), and N1303K (9.4%) accounted for 62.5% of CF alleles. Interestingly, in the Maronite group, 66.7% of the delta F508 chromosomes were found to be associated with allele 7 of the IVS8(T)tract, contrasting with the absolute linkage disequilibrium between European delta F508 chromosomes and allele 9. During this study, two previously undescribed polymorphisms (IVS14a + 17del5 and 2691T/C) were also identified.

First report of CFTR mutations in black cystic fibrosis patients of southern African origin.

Cystic fibrosis (CF) is thought to be rare in the black populations of Africa who have minimal white admixture. Only a few cases have been reported but have not been studied at the molecular level. We report the detection of CFTR mutations in three southern African black patients. One was homozygous for the 3120 + 1G-->A mutation, while the other two were compound heterozygotes each with this mutation on one chromosome. The other mutations were G1249E and a previously unreported in frame 54 bp deletion within exon 17a involving nucleotides 3196-3249 (3196del54). The 3120 + 1G-->A mutation was first described in American black patients and has been shown to be a common mutation in this population (9-14% of CF chromosomes). It was also found in a black CF patient whose father, the 3120 + 1G-->A carrier, is from Cameroon. These data suggest that it is an old mutation which accounts for many of the CFTR mutations in African blacks.