Estimation of risk as a function of risk factors. II.--Application to the multivariate analysis of coronary heart disease in a middle aged male population (author''s transl)

Peak expiratory flow rate (PEFR) was measured by means of a Wright peak flow meter on a sample of 2865 boys and 2712 girls selected at random in the Canton of Geneva, Switzerland (resident population of Swiss children and adolescents aged 4-19 1/2 in 1972). Technique of measurements and statistical analysis are described with an aim at standardization. Expected percentiles of PEFR (50, 25, 10 and 2.5) versus standing height are presented in tabular form for boys and girls separately. Nomograms are given allowing graphical determination of expected PEFR percentiles in either sex for any given standing height.     

Etude des caracteristiques du silicium et de l''aluminium atmospherique

We have studied two important characteristics of silicon and aluminium aerosols. Concentration by neutron activation analysis (N.A.A.); an average value of 10% for the A1 and Si content was found. Median size by use of diffusion battery; with assumption of log-normal distribution of diffusion coefficient we have obtained a in the region of 10⁻² μm for both total aerosol and Si and Al aerosol.     

The Ce3+ → Tb3+ transfer in phosphate host lattices

A Ce³⁺ → Tb³⁺ transfer has been shown to appear in various phosphates belonging to different structural types and particularly in some new compounds: Na₃Ln(PO₄)₂:Ce, Tb; Na_xSr_3?2xLn_x(PO₄)₂:Ce, Tb and KCaLn(PO₄)₂:Ce, Tb.The presence of [PO₄ groups, in which the P-O bonds are strongly covalent, leads to a relatively weak crystal field at the rare-earth sites. The best overlapping between cerium emission and terbium excitation spectra is obtained for phosphates containing alkali ions. This result can be explained by a lowering of the emitting level of the cerium 5d configuration due to stronger covalency of the CeO bond and to an increasing crystal field at the rare-earth sites.     

Study of the conformational rigidity of polyelectrolytes by elastic neutron scattering: 1. Carboxymethylcelluloses in the intermediate momentum range

Small angle elastic neutron scattered intensity l(q) by dilute solutions of a high molecular weight and low charge density carboxymethylcellulose (CMC) in D₂O, without added-salt has been measured. The variation of l(q) is proportional to q^?2 (q = momentum transfer) for $\text{q < q1}$, and to q^?1 for $\text{q > q1}$. The dependence on q^?2 shows that the distribution of the statistical units is Gaussian whereas the existence of $\text{q1}$ provides the possibility of calculating the length of such a unit; according to the dependence on q^?1, we conclude that these units are rigid. The length increases with dilution and charge density, which agrees with our previous results obtained by viscosity.     

Positional distribution on n−3 fatty acids in triacylglycerols from rat adipose tissue during fish oil feeding

The present study was designed to investigate the metabolism of the n−3 olyunsaturated fatty acids (PUFA) in adipose tissue and its dependence upon dietary factors. Changes in the positional distribution of the fatty acids in triacylglycerols from retroperitoneal adipose tissue were studied as a function of time on rats fed for 4 wk a diet enriched with fish oil. The stereospecific analysis of triacylglycerols was based on random formation ofrac-1,2-diacylglycerols by Grignard degradation. This was followed by synthesis ofrac-phosphatidic acids and treatment with phospholipase A₂. In the triacylglycerols of the fish oil diet, 57% of the total n−3 fatty acids were in position 3,i.e., two-thirds of 22∶5n−3 and 22∶5n−3 were esterified insn-3 position, whereas 22∶6n−3 was equally distributed in positions 2 and 3. After 4 wk of feeding fish oil, the fatty acid composition of adipose tissue triacylglycerols reached a steady state. Half of the n−3 fatty acids were found in position 3, namely 75% of 22∶5n−3, 50% of 20∶5n−3 and 18∶4n−3 and 45% of 22∶6n−3, the latter being equally distributed in positions 2 and 3. This pattern of distribution resembled that found in triacylglycerols of the fish oil diet, except for a higher proportion of 20∶5n−3 in adipose tissue in position 1 at the expense of position 3. Throughout the 4-wk period of fish oil feeding, the distribution pattern of minor n−3 fatty acids (18∶4n−3 and 22∶5n−3) in adipose tissue triacylglycerols remained unchanged. On the other hand, at the onset of fish oil feeding, 20∶5n−3 and 22∶6n−3 became concentrated in position 3, but thereafter 20∶5n−3 was progressively incorporated into position 1 and 22∶6n−3 into position 2. We thus conclude that n−3 fatty acids are differentially esterified in triacylglycerols of white adipose tissue. Despite the complex sequence of hydrolysis and acylation steps involved, the positional distribution of n−3 fatty acids was found to be similar in both the fish oil diet and the stored fat, in contrast to what was observed for nonessential fatty acids.     

The fractionation of marine-oil fatty acids with urea

Summary In two series of experiments, marine-animal-oil fatty acids were fractionated with urea using methanol as solvent. In the first series, menhaden-oil fatty acids were fractionated at 1°C. Almost all the saturated and monoenoic fatty acids were removed at mole ratios of 12∶1 to 13∶1. At higher ratios increasing amounts of the less stable dienoic fatty acids were precipitated. By the use of the appropriate ratio, fractions having iodine values above 300 were prepared. In the second series, fatty acids from the oils of menhaden, herring, tuna, seal, salmon eggs, and salmon heads and viscera were fractionated at a mole ratio of urea to fatty acid of 9.2∶1. At 25° and 1° the complexes were composed almost entirely of saturated and monoenoic fatty acids, but as the temperature was lowered to −30°, the content of dienoic fatty acids in the precipitates increased. Presented at the Regional American Chemical Society Meeting, Richland, Wash., June 11–12, 1954. One of the laboratories of the Branch of Commercial Fisheries, Fish and Wildlife Service, U. S. Department of the Interior.     

Influence of oxygen supply rates on performances of catalytic membrane reactors: Application to the oxidative coupling of methane

The impact of oxygen permeability using an ionic oxygen conducting membrane reactor with surface catalyst was investigated for the oxidative coupling of methane to higher hydrocarbons. Dense Ba_0.5Sr_0.5Co_0.8Fe_0.2O_3−δ (BSCFO), Ba_0.5Sr_0.5Mn_0.8Fe_0.2O_3−δ (BSMFO) and BaBi_0.4Fe_0.6O₃ (BBFO) membrane disks with Pt/MgO catalysts were prepared by sol–gel deposition or wash-coating. It is demonstrated that the oxygen supply by permeation needs to fit to the consumption during the coupling reaction. In case of insufficient oxygen supply comparably poor conversions are observed while higher oxygen fluxes lead to increased methane conversions, especially in the presence of an efficient catalyst. Generally, increasing catalytic activity leads to lower C₂ selectivity, especially for low oxygen permeation fluxes. The concept of a reactor employing dense catalytic membranes is viable, but the present study identifies further potential when the activity of the catalyst for the oxidative coupling is improved, leading to an overall enhanced performance of the membrane reactor.     

Extrinsic calibration of heterogeneous cameras by line images

The extrinsic calibration refers to determining the relative pose of cameras. Most of the approaches for cameras with non-overlapping fields of view (FOV) are based on mirror reflection, object tracking or rigidity constraint of stereo systems whereas cameras with overlapping FOV can be calibrated using structure from motion solutions. We propose an extrinsic calibration method within structure from motion framework for cameras with overlapping FOV and its extension to cameras with partially non-overlapping FOV. Recently, omnidirectional vision has become a popular topic in computer vision as an omnidirectional camera can cover large FOV in one image. Combining the good resolution of perspective cameras and the wide observation angle of omnidirectional cameras has been an attractive trend in multi-camera system. For this reason, we present an approach which is applicable to heterogeneous types of vision sensors. Moreover, this method utilizes images of lines as these features possess several advantageous characteristics over point features, especially in urban environment. The calibration consists of a linear estimation of orientation and position of cameras and optionally bundle adjustment to refine the extrinsic parameters.     

Sensory evaluation of the odour of a sunflower oil emulsion throughout oxidation

Oxidation of unsaturated fatty acids is responsible for off‐flavours, often described as rancid flavours. This study was aimed at describing the evolution of the odour of a sunflower oil‐in‐water emulsion during oxidation at 50 °C in the dark. Appearance of an odour and occurrence of oxidation were first tested for at short‐time aging (0–4 h) by the triangle test and measurements of oxygen consumption, respectively. The odour of the emulsion oxidised for up to 240 h was then characterised by sensory profile, while volatiles issued from lipid oxidation were analysed in the headspace by SPME. From 1 h of aging, while oxygen consumption remained weak, a significant change of the odour was detected by the panel. Up to 21 volatile compounds were identified in the headspace of long‐time‐oxidised emulsions. Beyond the rancid attribute, seven attributes were chosen to describe the odour of oxidised emulsions, four of which referring to solutions of a single volatile oxidation compound. The contribution of the fresh oil attribute, initially dominant, was progressively overtaken from 6 to 24 h of aging by the deep‐fried attribute, which later declined in favour of the painty attribute, predominant after 100 h. Evolution of intensity scores and contribution to odour profiles of attributes could not be easily related to one reference volatile compound or another, confirming the complex relationship between the generated volatile compounds and the perceived odour.     

deNO x reduction by methanol over Co/alumina

The temperature window of NO _x consumption lies between 140 and 500 °C. The 0.5 wt%Co/Al₂O₃ catalyst exhibits a total consumption of NO _x between 300 and 350 °C at a space velocity of 50 000 h⁻¹. The presence of acetonitrile and methylnitrite can explain the difference between N₂ formation and NO_x consumption at T< 400 °C. The Co²⁺, in octahedral site, has been shown to coordinate two NO molecules.