Influence of epoxides of androstane series on some effects of cortisol

Zusammenfassung Auf der Basis von Struktur-Aktivitätsuntersuchungen verschiedener Epoxyden der Androstanreihe konnte gezeigt werden, dass die Antiglucocorticoid-Eigenschaften solcher Verbindungen von einer besonders spezifischen Struktur abhängig sind.     

World Views. Elements of the Apostelian and General Approach

In the work of the late Belgian philosopher, logician and freethinker Leo Apostel (1924–1995) the concept of ‘world view’ is extensively developed. From the diverse research of Apostel, I gather and examine the constituents of a world view and their relationships. I propose to understand it as a pluralist and open, rationalised ontology of the ‘world whole’, comprising knowledge systems, valuative ethical systems and concomitant action guiding systems, to a large extent reflecting insight in the exact sciences. The prolific and scattered opus of Apostel renders my account of encompassing world views approximate and incomplete. It merely outlines the intrinsically unfinished project and presents a recent development. This development mainly involves our approach to the phenomenon of emergence from a quantum theoretical perspective. This revised version was published online in July 2006 with corrections to the Cover Date.     

In vivo imaging of Treg cells providing immune privilege to the haematopoietic stem-cell niche

Stem cells reside in a specialized regulatory microenvironment or niche, where they receive appropriate support for maintaining self-renewal and multi-lineage differentiation capacity. The niche may also protect stem cells from environmental insults including cytotoxic chemotherapy and perhaps pathogenic immunity. The testis, hair follicle and placenta are all sites of residence for stem cells and are immune-suppressive environments, called immune-privileged sites, where multiple mechanisms cooperate to prevent immune attack, even enabling prolonged survival of foreign allografts without immunosuppression. We sought to determine if somatic stem-cell niches more broadly are immune-privileged sites by examining the haematopoietic stem/progenitor cell (HSPC) niche in the bone marrow, a site where immune reactivity exists. We observed persistence of HSPCs from allogeneic donor mice (allo-HSPCs) in non-irradiated recipient mice for 30?days without immunosuppression with the same survival frequency compared to syngeneic HSPCs. These HSPCs were lost after the depletion of FoxP3 regulatory T (T(reg)) cells. High-resolution in vivo imaging over time demonstrated marked co-localization of HSPCs with T(reg) cells that accumulated on the endosteal surface in the calvarial and trabecular bone marrow. T(reg) cells seem to participate in creating a localized zone where HSPCs reside and where T(reg) cells are necessary for allo-HSPC persistence. In addition to processes supporting stem-cell function, the niche will provide a relative sanctuary from immune attack.     

Mechanical properties of directionally solidified lead-antimony alloys

The Pb-17wt% Sb alloy was directionally solidified under two solidification conditions: with different temperature gradients (G=0.93–3.67 K/mm) at a constant growth rate (V=17.50 μm/s) and with different growth rates (V=8.3–497 μm/s) at a constant temperature gradient (G=3.67 K/mm) in a Bridgman furnace. Microstructure parameters, such as primary dendrite arm spacing (λ₁), secondary dendrite arm spacing (λ₂), and dendrite tip radius (R), were measured. The microhardness (Hv) and ultimate tensile strength (σ) of the directional solidification samples were also measured. The influences of solidification and microstructure parameters on Hv and σ were investigated. The results obtained in this work were compared with similar experimental researches in literatures. It is shown that the Hv and σ values increase with the increase of G and V, but decrease with the increase of λ₁, λ₂, and R.     

Parametric oscillation in vertical triple microcavities

Optical parametric oscillation is a nonlinear process that enables coherent generation of 'signal' and 'idler' waves, shifted in frequency from the pump wave. Efficient parametric conversion is the paradigm for the generation of twin or entangled photons for quantum optics applications such as quantum cryptography, or for the generation of new frequencies in spectral domains not accessible by existing devices. Rapid development in the field of quantum information requires monolithic, alignment-free sources that enable efficient coupling into optical fibres and possibly electrical injection. During the past decade, much effort has been devoted to the development of integrated devices for quantum information and to the realization of all-semiconductor parametric oscillators. Nevertheless, at present optical parametric oscillators typically rely on nonlinear crystals placed into complex external cavities, and pumped by powerful external lasers. Long interaction lengths are typically required and the phase mismatch between the parametric waves propagating at different velocities results in poor parametric conversion efficiencies. Here we report the demonstration of parametric oscillation in a monolithic semiconductor triple microcavity with signal, pump and idler waves propagating along the vertical direction of the nanostructure. Alternatively, signal and idler beams can also be collected at finite angles, allowing the generation of entangled photon pairs. The pump threshold intensity is low enough to envisage the realization of an all-semiconductor electrically pumped micro-parametric oscillator.     

The effect of 2-ethylisothionicotinamide (TH1314) on the ascorbic acid and cholesterol content of the adrenal glands in rats

Zusammenfassung Bei ein- bis fünftägiger Verabreichung von 100 mg 2-Aethylisothionicotinamide (TH₁₃₁₄)/kg peroral kommt es bei Ratten nach 2 h zu einer Absenkung des Ascorbinsäuregehalts in den Nebennieren. Nach 14 h ist der Ascorbinsäuregehalt der Nebennieren wieder normal geworden. Nach 2 h wurden keine bedeutenden Veränderungen im Cholesterolgehalt der Nebennieren bemerkt, dagegen stieg der Cholesterolgehalt nach 14 h. stark an. Bei den absoluten Gewichten wurden keine bedeutenden Unterschiede beobachtet. Die Resultate zeigen, dass TH₁₃₁₄ die adrenocorticale Aktivität steigert.

---

---

Aided by a grant from the Sigrid Jusélius Foundation.