Melting Temperature of High-Temperature Fixed Points for Thermocouple Calibrations

Thermocouples can be calibrated at pure metal ingot-based fixed points at temperatures up to the freezing point of copper (1084.62 °C). For Pt/Pd thermocouples, the deviation from the accepted reference function very often takes an approximately linear form up to the copper fixed point. The calibration of Pt/Pd thermocouples may therefore be more amenable to extrapolation than that of Pt/Pt-Rh thermocouples. Here, the melting temperatures of a Co?CC and a Pd?CC eutectic fixed point are determined by extrapolating the deviation functions of several Pt/Pd thermocouples, after the fashion of Edler et al. The results are compared with the melting temperatures measured using non-contact radiation thermometry. The expanded uncertainty (k = 2) of the melting temperatures determined by extrapolation of the Pt/Pd thermocouple calibrations is ±0.32 °C for the Co?CC fixed point, and ±0.49 °C for the Pd?CC fixed point. For both fixed points, these uncertainties are comparable to those of non-contact radiation thermometry measurements. While a number of assumptions are made in performing the extrapolation of the calibrations, the method does appear to offer a useful complement to non-contact radiation thermometry measurements.     

Nucleic acid components in carbohydrate-rich food]

The content of nucleic acid components in numerous foods, especially carbohydrate-rich ones, has been investigated. The data obtained for bases (purines and pyrimidines) were calculated as nucleic-acid equivalents (RNA or DNA); the IMP content was calculated from the measured content of hypoxanthine. Not only did cultivated plants such as cereals and pulses show a high RNA-equivalent content but also vegetables such as spinach, leek, broccoli, Chinese cabbage and cauliflower. We found the same results in mushrooms including oyster, flat, button (whitecaps) and cep mushrooms. In many vegetarian instant meals, the addition of autolysed or hydrolysed yeast caused a large increase in the purine content. Most natural foods which contain resting cell tissue, such as grains of seed, have only high-molecular-mass nucleic acid components with different concentrations; however, growing cell tissue (e.g. soya-bean sprouts) show, as well as the nucleic acids, some lower-molecular-mass compounds.     

Bestimmung niedermolekular gebundener Purin- und Pyrimidinbasen in Lebensmitteln nach gelchromatographischer Isolierung und hydrolytischem Druckaufschlu?

Zusammenfassung Die gelchromatographisch abgetrennten und isolierten niedermolekularen Purin- und Pyrimidinverbindungen wurden nach hydrolytischem Druckaufschluß an einem Kationenaustauscher als freie Basen bestimmt. Diese Daten werden auch im Verhältnis zu den Gesamtgehalten der Basen des Substrates mitgeteilt. Es zeigte sich, daß bei unbehandelten Proben der Anteil der niedermolekular gebundenen Basen 5–15% (je nach Base und Lebensmittel) der jeweiligen Gesamtbasenmenge beträgt. Bei frischen, nicht erhitzten Lebensmittelproben findet ein schneller Abbau von Adeninnucleotiden zu Inosinnucleotiden und zu Hypoxanthin statt, so daß nur geringe Adeningehalte aus niedermolekularen Verbindungen angetroffen werden. Bei erhitzten Lebensmitteln ist der Anteil niedermolekular gebundener Purin- und Pyrimidinbasen durch Teilhydrolyse von Nucleinsüren höher. Er beträgt dann 30–50% (je nach Base und Lebensmittel) der jeweiligen Gesamtbasenmenge.

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Determination of purine and pyrimidine bases, bound in compounds of low-molecular weight after isolation by gelpermeation-chromatography and hydrolytic digestion under pressure

Summary Compounds with purine and pyrimidine bases of low-molecular weight were separated and isolated by gelpermeation-chromatography. After acid hydrolysis of nucleotides to free bases in a pressure digestion vessel the bases were separated on cation exchange resins. The data obtained are also reported in relation to the total base content of the substrate. It could be demonstrated that in untreated samples the portion of combined bases of low-molecular weight results in 5 to 15% of the corresponding total base content, depending on base and kind of food. In fresh unheated food samples adenine nucleotides are con verted rapidly to inosine nucleotides and hypoxanthine; therefore only a small share of adenine is found from compounds of low-molecular weight. In heated food the portion of combined low-molecular weight purine and pyrimidine bases proves to be much higher, due to partial hydrolysis of nucleic acids. It amounts to 30 to 50% of the total base content, depending on base and kind of food.

     

Zum Nachweis von Sesamöl

Proof of Sesam Oil A high-performance liquid chromatographic (h.p.l.c.) method for the simultaneous determination of sesamol, sesamol, sesamin and tocochromanols is described. Oils, fats or the unsaponifiable components of food (sesamol not determinable) are dissolved in n-hexan. The separation is carried out on a column of Li Chrosorb Si 60 (5μm, 25 × 0.4 cm) with 1,4-dioxan-n-hexan (6 + 94) or ethyl acetat-n-hexan (10 + 90) as mobile phase (1 ml min^?1) and fluorimetric detection at 330 nm (exitation at 295 nm). Several sesam-seed oils and food containing sesam-seed were analysed. The data presented illustrate that apparently unspoilt and non-refined sesam oils contain characteristic amounts of sesamolin, sesamin and tocopherols, only traces of sesamol were found in these oils.     

Electro‐optical transfer function preferences for LCD TVs: The effect of display brightness and surround illumination on preferred gamma

Abstract— Recent commercial liquid‐crystal‐display (LCD) televisions are larger and brighter than traditional televisions, thus impacting the viewing conditions in which they are viewed. These changes in viewing conditions may require different electro‐optical transfer functions (EOTFs) for LCD TVs than those for conventional TVs. Here, the way various EOTFs affect the preferred image quality of test images with changes in brightness and surround illumination conditions are examined. The first method used a gain, offset, and gamma (GOG) function with a range of gamma values, and the second method altered the intrinsic EOTFs. Image preference for the simulated EOTFs was determined using a paired‐comparison experiment for ten images. The first experiment took place in a darkened room at two display luminance levels. The results indicated that a gamma of 1.6 was most preferred overall although more so at a lower screen luminance level. In a second experiment, the procedure was repeated with a dim surround of 10% of the display's white point. With this surround, preference for a gamma value of around 1.6 at both screen luminance levels was more enhanced. These results indicated that image preference for different EOTFs is dependent on display luminance and that this dependence is maintained with a dim surround.     

Antioxidative Wirksamkeit von Tocochromanolen – Rangfolgebestimmung mit „Response Surface Methodology (RSM)”︁

Antioxidative Efficiency of Tocochromanols – Determination of the Sequence with ?Response Surface Methodology RSM)”? By a model study four tocopherols: α-T, β-T, γ-T and δ-T as well as the ex latice Heveae brasiliensis isolated three tocotrienols-(T₃): α-T₃, γ-T₃, and δ-T₃ were investigated on their antioxidative efficiencies to protect linoleic acid methyl ester. With fixed temperatures and appointed oxygen supply resulted from repeated measurements the values of the standard deviations of the dates. For each of the seven tocochromanols by using Response Surface Methodology as statistical Method a regression equation was formulated and further by multiple regression analysis evaluated and at last by 3-D-response surface graphically represented. So it is possible to present synoptically all the area of experience known by the variable conditions of the several experiments. A ranking of the tocochromanols depends on the choosen conditions for temperature and oxygen. Only δ-T was even effective by a residual amount of 25% in spite of the extreme condition of 80°C/20% O₂ within 6 hours.     

COMT genetic variation affects fear processing: Psychophysiological evidence.

Emotional dysregulation is a core characteristic of many psychiatric diseases, including the anxiety disorders. Although heritable influences account for a significant degree of variation in risk for such disorders, relatively few candidate susceptibility factors have been identified. A coding variant in one such gene, encoding the dopamine catabolic enzyme catechol-O-methyltransferase (COMT Val158Met), has previously been associated with anxiety and with anxiety-related temperament and altered neural responses to affective stimuli in healthy individuals. In 96 healthy women recruited from a sample of 800 participants according to genotype, the authors tested for an association between the DRD2/ANKK1 Taq Ia, the COMT Val158Met, and a psychophysiological measure of emotion processing, the acoustic affective startle reflex modulation (ASRM) paradigm, and found that COMT genotype significantly affected startle reflex modulation by aversive stimuli, with Met158 homozygotes exhibiting a markedly potentiated startle reflex compared with Val158 carriers. A trait measure of anxiety (Gray's Behavioral Inhibition System; J. A. Gray & N. McNaughton, 2000) was also associated with ASRM. The functional polymorphism in the dopamine D2 receptor (DRD2/ANKK1 Taq Ia) had no effect on startle modulation. The findings support prior genetic and neuroimaging associations of the COMT 158Met allele to affective psychopathology and alterations in neural systems for emotional arousal and regulation. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Video microscopic image processing facilitates the evaluation of light microscopic autoradiography at high magnification

Light microscopic autoradiographs of H-thymidine labelled unstained semithin sections of Xenopus laevis embryonic nuclei were examined with conventional Nomarski differential interference contrast, phase-contrast and video microscopy. Whereas at low magnification it was possible to obtain a photograph of the nuclear structure and the silver grains in one focal plain, at high magnification, with small depths of focus, a satisfactory image was not attainable. Therefore, we stored the images of the two different focus levels with a digital image processing system and combined both images by an arithmetic operation. This video microscopic technique allows the use of high magnification light microscopy with oil immersion objectives and the application of additional electronic contrast enhancing methods for an adequate and rapid analysis of light microscopic autoradiographs.     

A comparison of constant stimuli and gray‐scale methods of color difference scaling

Two psychophysical techniques, the method of constant stimuli and the gray‐scale comparison method, were used to determine color tolerances for three different color centers in the hue, chroma, and lightness directions in CIELAB color space. The same color‐difference pairs were used as the stimuli in both experiments. Although the results followed the same trends, they were different for the two techniques. Based on comparison of the validity and precision of the results, as well as the ease of implementation, use, and analysis, the method of constant stimuli is the preferable method. © 2002 Wiley Periodicals, Inc. Col Res Appl, 28, 36–44, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/col.