3,241 research outputs found
Radiative capture on neutron rich nuclei
The --cross sections for neutron--rich oxygen isotopes have
been calculated in the direct capture model. The experimental data for
can be reproduced using this
model. Compared to previous work the cross section for are enhanced considerably by factors between four
and 300.Comment: 5 pages + 1 figure (availbale on request), LaTex, IK-TUW-Preprint
940640
Regulation of 5-oxo-ETE synthesis in inflammatory cells
5-Oxo-ETE ist ein chemotaktischer Faktor für Granulozyten, der von der NADP+-abhängigen Dehydrogenase 5h-dh aus dem 5-Lipoxygenaseprodukt 5-HETE gebildet wird. Ziel dieser dreiteiligen Studie war es, die der 5-oxo-ETE-Produktion zugrunde liegenden Regulationsmechanismen aufzuklären. I. Einfluß von myeloider Zelldifferenzierung auf die Expression von 5h-dh in HL-60 und U-937 Zellen. Undifferenzierte HL-60 und U-937 Zellen produzieren vergleichbare Mengen von 5-oxo-ETE wie Monozyten oder Granulozyten. Differenzierung von U-937 Zellen mit PMA verdreifacht die Enzymaktivtät von 5h-dh, während die Behandlung von HL-60 Zellen mit dh-VitD3 diese verdoppelte. Der Einfluß von PMA auf 5h-dh wurde darüber hinaus in Mikrosomen von U-937 Zellen untersucht. Die Behandlung PMA verdreifachte Vmax, liess aber KM unbeeinflußt. II. Regulation der 5-oxo-ETE-Produktion durch oxidativen Stress und Glukose. Da der GSH-Redoxzyklus die Produktion von NADP+ zur Folge hat, stimulierten die Hydroperoxide H2O2 und tBOOH die Synthese von 5-oxo-ETE in U-937 Zellen. Aufgrund seiner Verarbeitung durch den Pentosephosphat Zyklus, der NAD+ in NADPH umwandelt, inhibierte Glucose diesen Effekt von H2O2. Die Synthese von 5-oxo-ETE wurde durch H2O2 auch in humanem Monozyten, Lymphocyten und Thrombozyten, aber nicht in Neutrophilen angeregt. Im Gegensatz zu Monozyten zeigten sich Thrombozyten und Lymphozyten allerdings glukose-resistent. T-BOOH ehöhte auch die Produktion von 5-oxo-ETE nach Zugabe von Ionophore und Arachidonsäure zu mononukleären Blutzellen. III. 5h-dh-Expression in human Strukturzellen. Zunächst rasterten wir mehrere sekundäre Epithelzelllinien und fanden 5h-dh in allen Zellen. Drei Indizien lassen vermuten, daß die epithele 5h-dh der myeloiden entspricht: (i) die enzymatische Aktivtät liegt vor allem in der mikrosomalen Fraktion vor, (ii) bei dem Kofaktor handelt es sich um NADP+ und nicht um NAD+, und (iii) 5S-HETE ist das bevorzugte Substrat. Weitere Studien zeigten, daß auch primäre humane Aorta-Endothelzellen 5h-dh expremieren. Vergleichbar zu Entzündungszellen wird die Produktion von 5-oxo-ETE auch in Endothel- und in Epithelzellen durch oxidativen Stress angeregt.5-Oxo-ETE is a highly potent granulocyte chemoattractant that is formed by the NADP+-dependent dehydrogenase 5h-dh by oxidation of the 5-lipoxygenase product 5-HETE. The objective of this study was to investigate underlying regulatory mechanisms of 5-oxo-ETE production in human cells. This matter was addressed from three directions. I. Expression of 5h-dh in HL-60 and U-937 cells and its activity changes during myeloid cell differentiation. Undifferentiated U-937 and HL-60 cells produce similar amounts of 5-oxo-ETE compared to monocytes or neutrophils. Differentiation of U-937 cells with PMA resulted in a 3-fold increase in 5-oxo-ETE production. Similarly, incubation of HL-60 cells with dh-VitD3 induced a 2-fold increase in 5-oxo-ETE production. The impact of PMA on 5h-dh was also investigated in the microsomal fraction of U-937 cells and compared to neutrophil microsomes. PMA treatment leads to a increase of Vmax but does not affect KM. II. Regulation of 5-oxo-ETE by oxidative stress and glucose levels. We found that H2O2 and t-butyl hydroperoxide strongly stimulate 5-oxo-ETE formation by U-937 cells through the GSH redox cycle by providing NADP+. Glucose inhibited the response to H2O2 through its metabolism by the pentose phosphate pathway, which converts NADP+ back to NADPH. 5-Oxo-ETE synthesis was also strongly stimulated by hydroperoxides in blood monocytes, lymphocytes, and platelets, but not neutrophils. Unlike monocytic cells, lymphocytes and platelets were resistant to the inhibitory effects of glucose. 5-Oxo-ETE synthesis following incubation of peripheral blood mononuclear cells with arachidonic acid and calcium ionophore was also strongly enhanced by t-BOOH. III. Expression of 5h-dh in human structural cells. We screened several secondary epithelial cell lines and detected 5h-dh in all cell lines. Epithelial 5h-dh and the inflammatory cell 5h-dh are identical: (i) the enzymatic activity is localized in microsomes, (ii) the cofactor is NADP+, and (iii) 5S-HETE is the preferred substrate. We also found that primary human aortic endothelial cells express 5h-dh. 5-oxo-ETE production by both endothelial and epithelial cells is regulated by oxidative stress in a manner similar to inflammatory cells
Zum 100. Geburtstag Moritz Cantors
Das Mathematische Institut der Universität Heidelberg veranstaltete am 9. November 1929 unter der Leitung des Ordinarius Heinrich Liebmann eine Gedenkfeier zum 100. Geburtstag des Mathematikhistorikers Moritz Cantor.
Im Nachlass Karl Bopps, der von der Universitätsbibliothek Heidelberg verwahrt wird, findet man Briefe, Manuskripte und Zeitungsausrisse zu diesem Ereignis.
- 1. Zum Gedächtnis Moritz Cantors / von Rudolf Horn
- 2. Gedenkrede gehalten zur 100. Wiederkehr des Geburtstages von Moritz Cantor / von Karl Bopp
- 3. Gedenkfeier für Moritz Cantor / Heidelberger Neueste Nachrichten
- 4. Festakt zum 100. Geburtstag von Moritz Cantor / Heidelberger Tageblatt
- 5. Einladungsliste zur Cantor-Feie
Lexical Culture
The paper focuses on the mutual relations between linguistics and lexicographAgainst the background of etymology and comparative-historical linguistic studies and using the words 'lexical' and 'culture' as examples, an attempt is made to demonstrate the relevance of morphology, grammar and semantics to the description of vocabulary and its lexicographic codification. Issues of intra lingual variety and interlingual diversity can now also be addressed Within the theoretical framework of contrastive textology, supported by computer-aided parallel text corpus analysis. However, lexicography is not entirely dependent on the results of linguistic research; it needs to move on and develop its own theoretical base. Recent progress in four fields of dictionary research has indeed contributed to an international upsurge of 'lexical culture'
General lexicography in Europe
On the basis of several surveys of experts, centres and projects in lexicography, and against the author's own experience of metalexicography, the paper traces the recent progress of academic lexicography, especially in Europe. Particular attention is paid to 'dictionary research' in four of its divisions. One special concern is the professionalisation of the discipline in terms of conferences, publications and training initiatives.Keywords:Â dictionary research, europe, lexicography, surve
Visual adaptation to thin and fat bodies transfers across identity
Visual perception is highly variable and can be influenced by the surrounding world. Previous research has revealed that body perception can be biased due to adaptation to thin or fat body shapes. The aim of the present study was to show that adaptation to certain body shapes and the resulting perceptual biases transfer across different identities of adaptation and test stimuli. We designed two similar adaptation experiments in which healthy female participants adapted to pictures of either thin or fat bodies and subsequently compared more or less distorted pictures of their own body to their actual body shape. In the first experiment (n = 16) the same identity was used as adaptation and test stimuli (i.e. pictures of the participant’s own body) while in the second experiment (n = 16) we used pictures of unfamiliar thin or fat bodies as adaptation stimuli. We found comparable adaptation effects in both experiments: After adaptation to a thin body, participants rated a thinner than actual body picture to be the most realistic and vice versa. We therefore assume that adaptation to certain body shapes transfers across different identities. These results raise the questions of whether some type of natural adaptation occurs in everyday life. Natural and predominant exposure to certain bodily features like body shape – especially the thin ideal in Western societies – could bias perception for these features. In this regard, further research might shed light on aspects of body dissatisfaction and the development of body image disturbances in terms of eating disorders
Performance Portability Study of Linear Algebra Kernels in OpenCL
The performance portability of OpenCL kernel implementations for common
memory bandwidth limited linear algebra operations across different hardware
generations of the same vendor as well as across vendors is studied. Certain
combinations of kernel implementations and work sizes are found to exhibit good
performance across compute kernels, hardware generations, and, to a lesser
degree, vendors. As a consequence, it is demonstrated that the optimization of
a single kernel is often sufficient to obtain good performance for a large
class of more complicated operations.Comment: 11 pages, 8 figures, 2 tables, International Workshop on OpenCL 201
- …