Attenuating Effect of Vigorous Physical Activity on the Risk for Inherited Obesity: A Study of 47,691 Runners

Objective: Physical activity has been shown to attenuate the effect of the FTO polymorphism on body weight, and the heritability of body weight in twin and in family studies. The dose-response relationship between activity and the risk for inherited obesity is not well known, particularly for higher doses of vigorous exercise. Such information is needed to best prescribe an exercise dose for obesity prevention in those at risk due to their family history. Design: We therefore analyzed self-reported usual running distance, body mass index (BMI), waist circumference, and mother’s and father’s adiposity (1 = lean, 2 = normal, 3 = overweight, and 4 = very overweight) from survey data collected on 33,480 male and 14,211 female runners. Age-, education-, and alcohol-adjusted regression analyses were used to estimate the contribution of parental adiposities to the BMI and waist circumferences in runners who ran an average of,3, 3–6, 6–9, $9 km/day. Results: BMI and waist circumferences of runners who ran,3 km/day were significantly related to their parents adiposity (P,10 215 and P,10 211, respectively). These relationships (i.e., kg/m 2 or cm per increment in parental adiposity) diminished significantly with increasing running distance for both BMI (inheritance6exercise interaction, males: P,10 210; females: P,10 25) and waist circumference (inheritance6exercise interaction, males: P,10 29; females: P = 0.004). Compared to,3 km/day, the parental contribution to runners who averaged$9 km/day was diminished by 48 % for male BMI, 58 % for female BMI, 55 % for male waist circumference, and 58 % for female waist circumference. These results could not b

The effect of higher order modes on the performance of large diameter dissipative silencers

Within the gas turbine industry dissipative silencers are regularly used to reduce broadband noise within duct systems. Silencer performance is normally quantified using the insertion loss due to a plane wave incident sound field. However for larger silencers the widths of these duct systems are large enough to allow higher order modes to propagate over much of the frequency range of interest (31-8kHz octave bands), which may have a significant effect upon silencer performance that is not normally accounted for. The performance of dissipative parallel baffle and bar silencers in the presence of different types of incident sound field is investigated through a numerical model which uses the finite element method and point collocation to predict insertion loss. Excitation of the silencer using an equal modal energy density sound field is found to have a large effect upon performance compared to plane wave excitation. Increases to insertion loss are predicted at high frequencies for the geometries modelled and it is found that plane wave predictions do not necessarily give the worst case performance

Penis-rejection in a mangrove littorinid snail: why do females reject males?

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Manipulating the H₂/CO ratio from dry reforming of simulated mixed waste plastics by the addition of steam

Two-stage pyrolysis-catalytic reforming of plastics was investigated with the aim of producing usable quality synthesis gases (syngas) comprised of H2 and CO. The process consisted of pyrolysis of the plastics in the first stage and catalytic reforming with CO2 and steam as the reforming agents in the second stage. The plastics used were a mixture of waste plastics prepared to represent those found in municipal solid waste and the catalysts studied were Ni-Co/Al2O3 and Ni-Mg/Al2O3 prepared by the rising pH technique. A range of different CO2/steam ratios were considered; 4:0, 4:0.5, 4:1, 4:1.5 and 4:2 for the Ni-Co/Al2O3 catalyst and 4:0, 4:0.5, 4:1, 4:2 and 4:3 for the Ni-Mg/Al2O3 catalyst. The results obtained demonstrated that the catalysts and the CO2/steam ratio influence the syngas quality, as represented by the H2/CO molar ratio value. With the Ni-Co/Al2O3 catalyst, the H2/CO molar ratio was increased from 0.74 (no steam) to 0.94 (CO2:steam ratio; 4:1) however the H2/CO molar ratio decreased with further steam addition. Results using the Ni-Mg/Al2O3 catalyst showed a different trend, wherein the H2/CO molar ratio increased with the increase of steam addition into the system. From the evaluation of the gas composition, the steam addition with the Ni-Mg/Al2O3 catalyst promoted hydrogen production while the Ni-Co/Al2O3 catalyst promoted carbon monoxide production. The addition of steam to the dry reforming of waste plastics has the potential to manipulate the H2/CO molar ratio hence, the quality of syngas produced can be matched to the desired end-use industrial application

Combustible gaseous products from pyrolysis of combustible fractions of municipal solid waste

Municipal Solid Waste (MSW) sample was pyrolysed under inert atmosphere of nitrogen in a static bed pyrolysis reactor, heated at a controlled rate of 10°C min-1 to a final temperature of 700°C to recover combustible gaseous product. The yield of the combustible gaseous product was 23.01 wt%. Other pyrolysis products were 32.00 wt% char and 44.99 wt% oil. The combustible gaseous product evolved, analysed off line by gas chromatography to contain mainly CO2, CO, H2, CH4, C2H6 and C3H8 has relatively high calorific value of 18.0 MJ m-3, making the gas suitable for use as a fuel. The significance of this research is that the pyrolysis recovered combustible gas can now be stored conveniently and easily transported for various applications. This research, in addition to providing energy needs if implemented, has the capacity to stimulate regular collection of MSW to feed a pyrolysis plant thereby reducing accumulation of the waste in communities, especially in developing countries

Steam reforming of biomass tar over tyre char for hydrogen production

Carbonaceous materials have been proven to have a high activity for tar removal. The simultaneous gasification of pyrolysis gases and char has a significant role in increasing the gas yield and decreasing the tar in the product syngas. This study investigates the use of tyre char as a catalyst for hydrogen production and tar reduction during the pyrolysis/reforming of biomass using a two stage fixed bed reactor. The biomass sample was pyrolysed under nitrogen at a pyrolysis temperature of 500 deg;C. The evolved pyrolysis volatiles were passed to a second stage with steam and the gases were reformed at a temperature of 900 deg;C with the presence of tyre char as catalyst. The influence of catalyst bed temperature, steam flow rate, reaction time and addition of metals were investigated. Char was characterized using BET surface analysis and scanning electron microscopy (SEM). Raising the steam injection rate and reforming temperature resulted in an increase in hydrogen production as steam reforming and gasification of char increased. Over the ranges of operating conditions examined, the maximum hydrogen content reached 52% and the ratio of H 2 /CO varied between 1.3 to 2. The presence of steam promotes the char conversion, however, increasing the amount of steam from 6.64 g/h to 8.64 g/h doesn't contribute to decrease the char yield and the obtained hydrogen yield was almost the same at about 51 vol. %. The results indicate that the char bed exhibited a higher tar reduction than the thermal cracking conditions

Quantile-Specific Penetrance of Genes Affecting Lipoproteins, Adiposity and Height

Quantile-dependent penetrance is proposed to occur when the phenotypic expression of a SNP depends upon the population percentile of the phenotype. To illustrate the phenomenon, quantiles of height, body mass index (BMI), and plasma lipids and lipoproteins were compared to genetic risk scores (GRS) derived from single nucleotide polymorphisms (SNP)s having established genome-wide significance: 180 SNPs for height, 32 for BMI, 37 for low-density lipoprotein (LDL)-cholesterol, 47 for high-density lipoprotein (HDL)-cholesterol, 52 for total cholesterol, and 31 for triglycerides in 1930 subjects. Both phenotypes and GRSs were adjusted for sex, age, study, and smoking status. Quantile regression showed that the slope of the genotype-phenotype relationships increased with the percentile of BMI (P = 0.002), LDL-cholesterol (P = 3×10−8), HDL-cholesterol (P = 5×10−6), total cholesterol (P = 2.5×10−6), and triglyceride distribution (P = 7.5×10−6), but not height (P = 0.09). Compared to a GRS's phenotypic effect at the 10th population percentile, its effect at the 90th percentile was 4.2-fold greater for BMI, 4.9-fold greater for LDL-cholesterol, 1.9-fold greater for HDL-cholesterol, 3.1-fold greater for total cholesterol, and 3.3-fold greater for triglycerides. Moreover, the effect of the rs1558902 (FTO) risk allele was 6.7-fold greater at the 90th than the 10th percentile of the BMI distribution, and that of the rs3764261 (CETP) risk allele was 2.4-fold greater at the 90th than the 10th percentile of the HDL-cholesterol distribution. Conceptually, it maybe useful to distinguish environmental effects on the phenotype that in turn alters a gene's phenotypic expression (quantile-dependent penetrance) from environmental effects affecting the gene's phenotypic expression directly (gene-environment interaction)

Pyrolysis/reforming of rice husks with a Ni–dolomite catalyst: Influence of process conditions on syngas and hydrogen yield

The influence of process conditions on the production of syngas and H2 from biomass in the form of rice husks was investigated using a two-stage pyrolysis/catalytic reforming reactor. The parameters investigated were, reforming temperature, steam flow rate and biomass particle size and the catalyst used was a 10 wt.% Ni–dolomite catalyst. Biomass was pyrolysed in the first stage, and the product volatiles were reformed in the second stage in the presence of steam and the Ni–dolomite catalyst. Increase in catalyst temperature from 850 °C to 1050 °C marginally improved total syngas yield. However, H2 yield was increased from 20.03 mmol g−1 at 850 °C to 30.62 mmol g−1 at 1050 °C and H2 concentration in the product gas increased from 53.95 vol.% to 65.18 vol.%. Raising the steam flow rate increased the H2 yield and H2 gas concentration. A significant increase in H2:CO ratio along with a decrease in CO:CO2 ratio suggested a change in the equilibrium of the water gas shift reaction towards H2 formation with increased steam flow rate. The influence of particle size on H2 yield was small showing an increase in H2 production when the particle size was reduced from 2.8–3.3 to 0.2–0.5 mm

Thermal degradation of real-world waste plastics and simulated mixed plastics in a two-stage pyrolysis-catalysis reactor for fuel production

Real-world postconsumer mixed plastics and a simulated mixture of plastics were processed in a two-stage pyrolysis-catalysis fixed bed reactor in the presence of a zeolite HZSM-5 catalyst. In addition, single plastic polyethylene, polypropylene, polystyrene, and polyethylene terephthalate were also processed in the two-stage reactor. The product yield, composition, and hydrocarbon distribution of the product oil was obtained in relation to plastic type. Noncatalytic pyrolysis of the plastics produced a high yield of an oil/wax product in the 81-97 wt % range. Addition of the catalyst reduced the yield of oil to between 44 and 51 wt %, with an increase in gas yield from cracking of the oil volatiles. However, the condensed oils produced from pyrolysis-catalysis were enriched with lower molecular weight (C5-C15) hydrocarbons and were markedly more aromatic in composition with a high proportion of single-ring aromatic hydrocarbons. Comparison of the results from pyrolysis and pyrolysis-catalysis of the simulated mixture of plastics with the data obtained for the individual plastics showed that significant interaction between the plastics occurred in the mixture with higher C2-C4 gas yield and higher aromatic content in the oils than expected from the proportions of the individual plastics in the mixture