Bestimmung natürlich vorkommender steroidaler Sexualhormone (Androgene und Gestagene) in Rindfleisch

The content of 10 naturally occurring steroidal sex hormones (androgens and progestogens), their biosynthetic precursors and metabolites was determined in 62 samples of beef (bulls, steers, heifers). After enzymatic hydrolysis of their conjugates, the steroids were extracted from the tissue by liquid-liquid extraction and purified by solid phase extraction. The identification and quantification was carried out by GC-MS of the trimethylsilyl ethers. The progestogens progesterone and pregnenolone were quantitatively dominant (43,7 and 6,5 μg/kg respectively). The highest steroid concentrations were determined in female cattle.     

Maternal presence and rearing condition affect responses to live predator in kangaroo rats (Dipodomys heermanni arenae).

Experiment 1 compared the responses of wild-caught adult and captive-born adult and juvenile kangaroo rats (Dipodomys heermanni arenae) to a live snake. Wild-caught adult rats were less active and monitored the snake more than during a control condition; captive-born juvenile rats did not behave differently during snake and control tests. Snake-naive adult rats behaved more like the wild-caught adult rats, but not on all measures. In Experiment 2, pups were tested at 25 and 50 days of age in 4 conditions: no-snake control, alone with the snake, with a sibling and the snake, and with the mother and the snake. Pups did not behave differently during control and snake tests, but during tests with the mother, pups faced the snake less and followed the mother. Younger pups were more often near the mother than a sibling and followed the mother more when the snake was present. Development of defensive behavior may depend on both predator experience and maternal influence. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Hypothesis formation as a facilitator of conceptual development.

Examined the role of hypothesis formation in the development of conceptual understanding of certain geometric principles of block design. 33 4–4? yr old children were instructed in the building of a series of 3-dimensional block designs under conditions which either permitted the use of copying strategies or mitigated against these and demanded hypothesis formation based upon partial information. No differences in error rate were found between conditions during duplication of familiar 3-dimensional block designs on a training test. Differences emerged when Ss were required to reconstruct, in 1 trial, from a photograph, familiar designs previously successfully duplicated from 3-dimensional models. Ss who originally had attempted to reconstruct 3-dimensional models under conditions requiring hypothesis formation, more accurately duplicated the complex, pictorial designs than did Ss who had reconstructed the 3-dimensional models under optimal cue conditions. Hypothesis formation, it is concluded, led to greater conceptual understanding of the geometric principles underlying the block designs. (French summary) (9 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

PROTEIN PRECIPITATION DURING WORT BOILING: QUALITY ASPECTS OF DIMINISHED WORT BOILING TIMES OF BREWS PREPARED FROM PROANTHOCYANIDIN-FREE OR REGULAR RAW MATERIALS

When using proanthocyanidin-free materials for the production of beer, a reduction of the wort boiling time can be considered. In worts prepared with regular malt and tannin-free hop extract there is a continuous precipitation of the malt flavanoids while in brews prepared from proanthocyanidin-free malt and regular hops there is a simultaneous extraction and removal of the hop flavanoids leading to constant levels of these hop flavanoids. The results also show that the level of Kjeldahl nitrogen in worts boiled with hops will be the same as that in worts boiled with n-hexane tannin-free hop extracts. These results and the fact that more protein precipitates in brews containing no malt or hop proanthocyanidins suggest that, unlike what is the case during the development of beer haze, polyphenols are not necessary for an effective protein precipitation during wort boiling.     

Subgrain growth in Al and Al-1% Mn during annealing

The subgrain growth during annealing of cold-worked Al-1% Mn and Al(4N) has been measured in the temperature intervals 300 to 400° C and 100 to 200° C respectively. For Al-1%Mn the subgrain diameter showed a parabolic growth, while for Al the diameter gradually reached a constant value. The microstructural investigations which included in situ annealing in a high voltage electron microscope demonstrated that the operating mechanism for growth in the higher temperature range was collective migration of sub-boundary dislocations. In the lower temperature range extraction of dislocations was found to be the dominating mechanism, i.e. dislocations partly lying in the boundaries are pulled out by the stress field in the subgrain interior. The observed growth rates were consistent with models for these mechanisms presented in two previous papers.     

Verifying programs by induction on their data structure: General format and applications

As a static object, a program presents two axes of complexity: the control structure and the data structure. The invariant assertion method is used to prove programs by induction on their control structure: The correctness of complex control structures is deduced from the correctness of their components, which are, in some sense, simpler. Orthogonally, one may want to prove programs by induction on their data structure: the correctness of the program on complex data items is deduced from its correctness on simpler data items. A general theorem of correctness by induction on the data structure is given. This theorem is applied with two distinct definitions of complexity (i.e., two distinct ordering relations on the space of the program) yielding, respectively, the subgoal induction method and the intermittent assertion method.     

Microelectrode biosensor for real-time measurement of ATP in biological tissue

The purines ATP, ADP, and adenosine are important extracellular signaling agents. Analysis of purinergic signaling has been slowed by lack of direct methods for measurement of purine release in real-time during physiological activity. We have previously reported microelectrode biosensors for adenosine, but similar sensors for ATP have remained elusive. We now describe an ATP biosensor formed by coating a Pt microelectrode with an ultrathin biolayer containing glycerol kinase and glycerol-3-phosphate oxidase. It responds rapidly (10-90% rise time <10 s) and exhibits a linear response to ATP over the physiologically relevant concentrations of 200 nM-50 microM and is very sensitive approximately 250 mA.M(-1).cm(-2). By including phosphocreatine kinase in the biolayer, we can optionally amplify the ATP signal and also make the sensor sensitive to external ADP. We have used our sensors to make the first demonstration that ATP is released from spinal networks in vivo during locomotor activity.     

Computation of time-domain response of URC networks

Computer-simulation results of the evaluation of the step response of uniformly distributed RC networks (URC networks) are presented, using Liou's procedure. The advantages of using the procedure include obviating the finding of poles of the transfer function and ease of accommodating boundary conditions, as well as good numerical control.     

Sinus aspergillosis after an endodontic treatment. Presentation of a clinical case

Aspergillosis is an opportunistic deep mycosis that occurs in immunocompromised patients, often in the paranasal sinuses. However, it sometimes occurs in healthy subjects, producing symptoms similar to those of a chronic sinusitis that is unresponsive to conventional treatment. A possible entry point for Aspergillus is the oroantral communication originated by perforation of the dental root cavity during root canal of a molar with penetration of material. We report the clinical case of a patient with symptoms of chronic sinusitis who was diagnosed as sinus aspergillosis after radiological and histological study. The origin may have been a third upper molar in which a root canal was performed.