HPLC ANALYSIS OF ALL POSITIONAL ISOMERS OF THE MONOHYDROPEROXIDES FORMED BY SOYBEAN LIPOXYGENASES DURING OXIDATION OF LINOLEIC ACID

Linoleic acid was oxidized by soybean lipoxygenases I and II (LOX-I and LOX-II). The monohydroperoxides (HPOD) formed were isolated and then hydrogenated. The mixtures of hydroxystearic acid isomers obtained were converted to phenacylesters and analyzed by HPLC. The isomers were identified on the basis of cochromatography with reference materials and mass spectrometry. It was shown that LOX-II forms mainly the 9-and 13-HPOD (94%) and in addition the 8-, 10-, 12- and 14-HPOD as minor components (6%) of the monohydroperoxide fraction. The minor hydroperoxides were absent when the catalyst was LOX-I. The presence of the poly ene crocin in the reaction system containing LOX-II changed the composition of the HPOD mixture. The proportion of the 13-HPOD increased at the expense of both the 9-HPOD and the minor hydroperoxides.     

A CELL KINETIC STUDY ON THE CANCER PROBLEM BASED ON THE AUTOMATIC CONTROL THEORY USING DIGITAL SIMULATION

Abstract

This paper deals with a general multi-loop automatic control system of the cell renewal process which makes possible the study of the dynamic response of a complete cell group or a compartment. At the same time the behavior of a single cell is observed as to the variability of its mean life span and the possibility of its irradication at any desired moment.

By means of the special block-oriented programming language ASIM (Analog SIMulation) of AEG-Telefunken numerous disturbed cases have been simulated, for example the response to perturbation of the cell numbers in different compartments has been calculated and thoroughly studied.

Several cell renewal systems, both normal and impaired growth, have been simulated and the results interpreted. The mean life span of the cells has been varied and structural changes of the feedback loops of the complex multivariable control system have been carried out.

The aforementioned cases in particular lead to the basic question whether malignant disorders are to be interpreted as unstable closed-loop control systems, the cause for the malignant growth being a structural defect of the feedback mechanism.     

The influence of light and wind on the fluorescence spectra of oil pollutions

The differences in the fluorescence spectra of 42 oil samples, which are measured with a laboratory arrangement, are discussed. It appears that the accuracy of these measurements gives the possibility of discriminating between a large number of oil samples. Special attention is given to the changes in the spectra caused by light and wind action. These changes are large compared with the differences that can be distinguished in the spectra.     

Green's functions and magnetized ferrites

Magnetized ferrites play an important role in the field of microwaves as substrates in various electronic elements. The dyadic Green's functions method is used to solve the electromagnetic field problem for such anisotropic (magnetically gyrotropic) materials. The full dyadic problem is reduced to a scalar one where the complete information is contained within a single scalar Green's function. A connection between the Green's functions formalism and that of scalar Hertz potentials is established and some progress is made towards the calculation of the scalar Green's function.     

层状液晶乳液的缓释效应

重点讨论了层状液晶乳液体系在应用到衣物柔顺剂中时其乳液结构及油相的极性对提高挥发性物质长久保留功效的影响。采用固相微萃取和气相色谱/质谱的分析技术,测定了顶空中挥发性物质的浓度随时间的变化,结果发现由聚氧乙烯醚失水山梨醇脂肪酸酯、失水山梨醇脂肪酸酯、长链脂肪醇、油和水组成的水包油型球形洋葱状层状液晶乳液LO1相和水包油型球形洋葱状LO1与平面层状Lβ的混合两相在应用过程中能够最有效地延缓具有低极性的挥发性物质的释放平衡,相反油包水型球形洋葱状层状液晶LO2和平面层状液晶Lβ不能有效地提高挥发性物质任何阶段中在织物上的沉积和保留。     

Spectral signal to clutter and thermal noise properties of ocean wave imaging synthetic aperture radars

Abstract

The high wavenumber detection cut-off is determined above which the spectrum of ocean waves imaged by a synthetic aperture radar (SAR) is lost in the background noise spectrum consisting of the clutter noise associated with the Rayleigh statistics of the backscattering surface and the thermal noise originating in the SAR system itself. For given power, the maximum detection cut-off wavenumber is attained if the SAR resolution is chosen such that the clutter and noise spectra are equal at the cut-off wavenumber. Assuming a constant modulation transfer function relating the image modulation and wave slope spectra, the cut-off wavenumber is in this case proportional to (ρ_aρ_g)^?1/2, where ρ_a and ρ_g represent the full bandwidth (single look) azimuthal and ground range resolutions, respectively. The same proportionality holds (but with a cut-off wavenumber increased by a factor √2) for a clutter limited cut-off, the normal operating condition of an SAR. To first order, incoherent multilook averaging has no influence on the signal-to-background detection cut-off wavenumber, provided the reduced Nyquist cut-off wavenumber resulting from the reduced multilook spatial resolution remains greater than the signal-to-background cut-off wavenumber. Estimates of the detection cut-off wave-numbers are given for the Seasat SAR and the SAR proposed for the European Remote Sensing Satellite ERS-1.     

The effect of monomolecular surface films on the microwave brightness temperature of the sea surface

Abstract

Airborne microwave radiometer measurements at 1·43 and 2·65 GHz over a sea surface covered with a monomolecular oleyl alcohol surface film and over adjacent slick sea surfaces are presented. The measurements show that at 2·65 GHz the brightness temperature T _B is not affected by the slick, while at 1·43 GHz it drops from 93 K to a minimum value of almost O K. This implies that at 1·43 GHz the emissivity of the slick-covered sea surface is extremely small, similar to a metallic layer, and that this resonant-type phenomenon is confined to a narrow frequency band of width δ?/ ?<0·6.

The theoretical implications of these experimental findings are discussed in the framework of the Debye relaxation theory of polar liquids. It is conjectured that a thin layer of water molecules polarized by the surface film gives rise to an anomalous dispersion, which causes the large decrease in brightness temperature at 1·43 GHz.

The modulus of the relative dielectric constant ε? is estimated to be ≥ 5·2 × 10^?4 and the thickness of the emitting layer ≤1·9 × 10^?4 m for 1·43 GHz. Furthermore, the film-induced surface activation energy is calculated to be 9·18 × 10^?21 J. These values seem reasonable in the light of the theories on the physicochemical structure of surface layers.     

Lorentz Force Velocimetry for Poorly Conducting Fluids-Development and Validation of a Novel Flow Rate Measurement Device

The paper demonstrated the feasibility of Lorentz Force Velocimetry for flow rate measurements of weakly conducting electrolytes using experimental results on salt water flow exposed to a permanent magnet system.This innovative flow measurement technique allows the non-contact determination of flow rates and relies on the interaction between a magnetic field and a moving conducting fluid.When an electrically conducting fluid moves through the magnetic field a Lorentz force is generated and acts on the measurement system.The present report provides an overview about the experimental setups and the first measurement results.     

On the temperature in the wheel–rail rolling contact*

The flash temperature in an asperity of the rail due the wheel–rail rolling contact is investigated. First the contact configuration and the total heat produced are explained. Then approaches to heat partitioning between the two contacting bodies are discussed. A new heat partitioning factor is derived for the case of frictional heating and heating due to plastic deformation, thereby taking into account the roughness of the contacting surfaces by a contact intensity factor distribution as well as the local pressure intensification by individual asperities. Several roughness distributions are studied. Finally, an explicit calculation is outlined of the asperity flash temperature at the end of the contact, expressed by two temperatures and two factors contributing to the partitioning of heat between the contacting bodies.     

High-temperature Solar Thermal Energy Storage

The mislocation of solar energy production facilities and points of demand and the temporal mismatch of solar energy availability and energy demand make transport and storage of solar energy essential. Research at the Solar Energy Research Institute has focused on high-temperature, diurnal storage because of the frequency of use and the potential for conservation of premium fossil fuels. Also, high-temperature thermal energy storage can reduce the cost of hydrogen production, electricity and heat produced by cogeneration, and methane reforming. SERI research is concentrating on containment techniques (including materials corrosion, internal insulation, and storage medium for high-temperature molten salts) and direct-contact heat exchange (including cost-effective heat exchanger design and heat transfer of various materials). After initial screening tests we selected carbonates for further study. We are now constructing test equipment that will allow heat transfer experiments with molten carbonate to 700°C