Comparison of the relative quantities of aroma compounds found in fresh apricot (Prunus armeniaca) from six different varieties

Summary The volatile components of fresh apricot (Prunus armeniaca) were isolated by vacuum distillation and fractionated on a silica gel column. Analysis by gaschromatography coupled with mass spectrometry led to the identification of 82 compounds, 60 of which were found for the first time in this fruit. Six varieties, cultivated in the south of France were compared for their firmness, acidity, sweetness and for their content of 56 volatile components. Precoce de Tyrinthe was the least aromatic variety, but produced fruits very early in the season. Palsteyn gave acidic but rather aromatic fruits. Moniqui possessed large but perishable fruits with flowery aroma due to the presence of terpenic ketones. Rouge du Roussillon contained all the identified volatile compounds and possessed a pleasant aroma. Polonais contained many C₆-compounds with herbaceous notes and Bergeron was rich in lactones but poor in terpenic alcohols.

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Über die Gehalte an Aromakomponenten von sechs Aprikosensorten (Prunus armeniaca)

Zusammenfassung Die flüchtigen Aromastoffe von Aprikosen (Prunus armeniaca) wurden durch Vakuumdestillation und anschließende chromatographische Vortrennung und Kieselgel isoliert. Mit kombinierter gaschromatographischer Analyse wurden 82 Komponenten, davon 60 zum ersten Mal, identifiziert. Die Gehalte an Zucker, Säuren und 56 Aromakomponenten von 6 französischen Aprikosensorten wurden miteinander verglichen. Die Sorte Precoce de Tyrinthe ist wenig aromatisch aber frühreif, die Sorte Moniqui trägt große Früchte mit einem Blumenaroma von Ketonen, während Rouge du Roussillon viele Komponenten und das angenehmste Aroma besitzt. Die Sorte Polonais zeichnet sich durch den höchsten Gehalt an C₆-Komponenten und ein krautartiges Aroma aus. Die Sorte Bergeron ist reich an Lactonen, jedoch arm an Terpenalkoholen.

     

Probabilistic risk analysis and risk-based priority scale for the tiles of the space shuttle

The thermal protection system of the space shuttle is one of its most critical subsystems because it protects the orbiter from heavy heat loads at reentry into the atmosphere. To optimize NASA's allocation of risk management resources, a probabilistic risk analysis model is developed for the black tiles, and a risk-criticality index is computed for each tile based on its contribution to the overall probability of loss of vehicle and crew (LOV/C). This assessment is based on the susceptibility of the tiles (i.e. their probabilities of debonding), and on the vulnerability of the orbiter to specific tile losses given the criticality of the subsystems under the aluminum skin in various locations. The two main initiating events are linked to the debonding of a tile, caused either by debris hits or by a weak bond because of poor tile installation. The PRA model relies on a partition of the orbiter's surface according to four parameters: the probability of debris hits, the probability of secondary tile loss once a first tile has debonded, the probability of burnthrough given a failure patch of specified size, and the probability of LOV given a hole in the orbiter's aluminum skin. The results show that the contribution of the tiles to the overall probability of LOV is about 10%. They also include a map of the orbiter's surface showing the relative risk-criticality of tiles at various locations. It was found that 85% of the risk can be attributed to 15% of the tiles, thus allowing the management to allocate more effort and resources to the maintenance of the most risk-critical tiles.     

Happiness and reminiscing: The role of time perspective, affect, and mode of thinking.

Conducted 3 experiments to determine the affect of reminiscing on reported well-being. 51 students at a professional school for translators and interpreters in Exp I and 36 undergraduates in Exp II recounted events that they had experienced as positive and pleasant or as negative and unpleasant. In Exp III, 64 undergraduates wrote down a particularly positive or negative event and then asked to explain either why or how this event occurred. Ss in all 3 experiments were then asked to rate their happiness and life satisfaction. Overall results indicate that Ss' ratings of general life satisfaction depended not only on the hedonic quality of the life experiences they happened to recall but also on the way in which they thought about them. Specifically, the hedonic quality of present life events influenced Ss' judgments of well-being in the same direction. The hedonic quality of past events, however, had a congruent impact on well-being judgments only when thinking about them elicited affect in the present but otherwise had a contrast effect on these judgments. Two factors were found to determine if thinking about the past elicits affect: whether Ss describe the events vividly and in detail or only mention them briefly, and whether Ss describe how the events occurred rather than why they occurred. (22 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Einflu? der verwendeten Methoden bei der Bestimmung von Ballaststoffen und verwertbaren Kohlenhydraten auf die Berechnung des Energiegehalts von Broten

Zusammenfassung Der Ballaststoffgehalt verschiedener Brote wird nach zwei Methoden bestimmt. Mit der modifizierten Neutraldetergentien-Methode werden durchschnittlich 60% der enzymatisch-chemisch bestimmbaren Ballaststoffe erfaßt. Für die Bestimmung des Brennwertes werden die Hauptinhaltsstoffe analytisch bestimmt, die verwertbaren Kohlenhydrate werden zusätzlich nach verschiedenen Verfahren durch Differenz berechnet. Der Energiegehalt wird mit den allgemeinen Atwater-Faktoren (4/9/4), spezifischen Faktoren und mit den physikalischen Brennwerten der resorbierbaren Nährstoffe berechnet.

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The effect of methods used for the determination of dietary fiber and available carbohydrates on the calculation of the physiological fuel value of breads

Summary The dietary fiber content of German breads was determined by two different methods. With a modified NDF-method 60% of total dietary fiber (determined by an enzymatic-chemical procedure) are detected. For estimation of the physiological fuel value the main components of breads were determined by analysis. In addition, the carbohydrates were determined by difference, using various methods of calculation. For the estimation of the caloric value, different calorie conversion factors are used.

     

An optimisation strategy in a digital environment applied to neonatal chest imaging

The aim of this study was to find the optimum tube voltage for neonatal chest imaging in computed radiography. The study was designed to take full advantage of the benefits of digital imaging, for example, by comparing the tube voltages at constant effective dose. A phantom study using a living rabbit was first conducted. Images were collected at tube voltages ranging from 40 to 90 kV(p). The reproduction of four structures (central vessels, peripheral vessels, carina and thoracic vertebrae) was rated by 10 radiologists. The reproduction of both central and peripheral vessels was relatively independent of tube voltage. The carina was better reproduced at higher tube voltages whereas the opposite was true for the thoracic vertebrae. Based on the higher importance of the reproduction of the carina it was decided that 90 kV(p) was the optimal tube voltage. To validate the result from the phantom study, a follow-up study was conducted in which images of neonates collected at the tube voltage regularly used at Sahlgrenska University Hospital (70 kV(p)) were compared with images collected at the tube voltage proposed by the phantom study. The follow-up study confirmed the results from the phantom study that the reproduction of the carina was better at 90 than at 70 kV(p). In conclusion, for neonatal chest imaging-given the same effective dose-90 kVp gives better reproduction of important structures than the regularly used 70 kV(p).     

Large-area Fabry-Perot modulator based on electro-optic polymers

We present a large-area electro-optic Fabry-Perot modulator utilizing a photoaddressable bis-azo polymer placed between two dielectric mirrors with an open aperture of 2 cm. A modulation efficiency of 1% at an effective modulation voltage of 20 V for a wavelength of 1.55 microm is demonstrated. By comparing distance tuning of the cavity with wavelength tuning, an effective electro-optic coefficient of -7 pm/V is measured.     

Accurate polarization measurements with a dual photoelastic modulator

Measurements of the polarization effects in multimirror experiments by using a dual photoelastic modulator are described. The effect of single and multiple mirrors in polarization measurements in two and three dimensions is discussed, and experimental results show how symmetrical placement of mirrors in three-dimensional geometry can eliminate changes in the polarization. Calibration procedures for a dual photoelastic modulator and potential error sources such as misalignment of analyzer, signal dc offset, and neglect of aperture size are presented. Mirror-surface evolution and how it can disturb the polarization measurement are also addressed.     

Mechanisms of water-holding capacity of meat: The role of postmortem biochemical and structural changes

Unacceptable water-holding capacity costs the meat industry millions of dollars annually. However, limited progress has been made toward understanding the mechanisms that underlie the development of drip or purge. It is clear that early postmortem events including rate and extent of pH decline, proteolysis and even protein oxidation are key in influencing the ability of meat to retain moisture. Much of the water in the muscle is entrapped in structures of the cell, including the intra- and extramyofibrillar spaces; therefore, key changes in the intracellular architecture of the cell influence the ability of muscle cells to retain water. As rigor progresses, the space for water to be held in the myofibrils is reduced and fluid can be forced into the extramyofibrillar spaces where it is more easily lost as drip. Lateral shrinkage of the myofibrils occurring during rigor can be transmitted to the entire cell if proteins that link myofibrils together and myofibrils to the cell membrane (such as desmin) are not degraded. Limited degradation of cytoskeletal proteins may result in increased shrinking of the overall muscle cell, which is ultimately translated into drip loss. Recent evidence suggests that degradation of key cytoskeletal proteins by calpain proteinases has a role to play in determining water-holding capacity. This review will focus on key events in muscle that influence structural changes that are associated with water-holding capacity.