Die Synthese von 3β-Acetoxy-24-aza-24-desoxa-xysmalogenin,. Partialsynthetische Versuche in der Reihe der Herzgifte. 12. Mitteilung,

Synthesis of 3β-acetoxy-24-aza-24-desoxa-xymalogenin Starting from the pregnenolone-derivative 1 we report the synthesis of the possibly cardiac-active compound 24-aza-24-desoxa-xysmalogenin 15 .     

Über ein Verfahren zur Erzeugung zweiseitig eingespannter,kurzer Polyethylen-Modellketten

Zusammenfassung Ein Algorithmus zur Erzeugung zweiseitig eingespannter Polyethylen-Modellketten im Diamantgitter wird vorgestellt, dessen Grundidee folgendermaßen angegeben werden kann: Die Gesamtheit der Modellketten bestimmter Kettenlängen zu einem vorgegebenen Anfang-End-Vektor erhält man, indem man zunächst die Grundverteilung zu diesem Anfang-End-Vektor bestimmt, durch Hinzufügen von geeigneten Paaren einander entgegengesetzter Gittervektoren die für die gegebene Kettenlänge möglichen Vektorverteilungen ermittelt und schließlich zu diesen alle möglichen Anordnungsmöglichkeiten der Gittervektoren sucht. Der Algorithmus wird im Abschnitt 2.1. am Beispiel des ebenen Wabengitters erläutert und dann im Abschnitt 2.2. auf das dreidimensionale Diamantgitter angewendet. Das Flußschema des entsprechenden Computerprogramms ist im Anhang angegeben.

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An instruction is given for generating polyethylene model chains fixed at their two ends in the diamond lattice. The fundamental thought is as follows: The ensemble of model chains of given length and end-to-end vector is obtained in three steps. First of all the basic distributions of chain vectors belonging to is determined. Secondly, all the possible distribution of chain vectors consistent with given chain length are found by addition of suitable pairs of opposite chain vectors to the basic distribution. Thirdly, all the allowed sequences of chain vectors are arranged.In section 2.1. this method is demonstrated for the plane honeycomb lattice. In section 2.2. it is applied to the tridimensional diamond lattice.The flow diagram of the computer programme is given in the appendix.

     

High precision procedure for determination of selected herbicides and their degradation products in drinking water by solid-phase extraction and gas chromatography-mass spectrometry

For target monitoring of selected herbicides in groundwater transport studies, a precise and accurate method for the determination of atrazine (ATR), desethylatrazine (DEAT) and 2,6-dichlorobenzamide (BAM) was developed. The method is based on solid-phase extraction and GC-MS analysis. Deuterated standards are used as surrogates for calibration by the overall procedure. For legal requirements the method described was validated and is regularly subject to external quality control. Typical limits of detection are 2 ng/l. Uncertainty contributions were evaluated using the GUM workbench modelling software. At the concentration level of interest (100 ng/l), an expanded uncertainty of no more than 10% was estimated. Accurate data on the distribution of ATR, DEAT and BAM in affected well fields enabled operational changes to be implemented to control the drinking water supply according to legal requirements.     

Education in medical genetics for non-genetic health care providers in Sweden

We investigated the content and extent of education in medical/clinical genetics among Swedish universities, university colleges and colleges of health providing undergraduate education for medical doctors and nurses. In addition, selected medical specialist training programmes and programmes for midwives and district nurses were analysed to detect elements of education or training in medical/clinical genetics. The main results are that, although basic cell biology is taught during the first semesters in all education, there is little or no genetics taught during the clinical parts of the educational programmes. Moreover, with regard to post-graduate education, it is almost absent. There is a need to improve education and training in genetics for all health care professionals to meet the expected increase in genetic issues in clinical medicine.     

Magnetically induced phonon anisotropy in ZnCr2O4 from first principles

We have studied the influence of magnetic order on the optical phonons of the geometrically frustrated spinel ZnCr2O4 within density-functional theory. By mapping local spin density approximation plus Hubbard U (LSDA + U) phonon calculations onto a Heisenberg-like model, we developed a method to calculate exchange derivatives and subsequently the spin-phonon coupling parameter from first principles.