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.     

Bismuth( Ⅲ ) Salts: Green Catalysts for Organic Transformations

1Introduction Bismuth, the heaviest stable element in the periodic table, stands out from other heavy elements (such as mercury, thallium and lead) due to its relatively non-toxic character which confers on bismuth the enviable status of being an eco-friendly element. Therefore, bismuth and its compounds hold considerable promise as useful catalysts for green chemistry. The research presented in this communication is devoted to the applications of bismuth( Ⅲ ) salts as catalysts for organic transformations.After some general comments about bismuth and a short presentation of the various applications of bismuth( Ⅲ ) salts in organic synthesis, this communication will focus on the works done in our research group during the last several years which deals mainly with electrophilic substitutions. When appropriate, some mechanistic details will be given.     

Strontium isotope evidence for landscape use by early hominins

Ranging and residence patterns among early hominins have been indirectly inferred from morphology, stone-tool sourcing, referential models and phylogenetic models. However, the highly uncertain nature of such reconstructions limits our understanding of early hominin ecology, biology, social structure and evolution. We investigated landscape use in Australopithecus africanus and Paranthropus robustus from the Sterkfontein and Swartkrans cave sites in South Africa using strontium isotope analysis, a method that can help to identify the geological substrate on which an animal lived during tooth mineralization. Here we show that a higher proportion of small hominins than large hominins had non-local strontium isotope compositions. Given the relatively high levels of sexual dimorphism in early hominins, the smaller teeth are likely to represent female individuals, thus indicating that females were more likely than males to disperse from their natal groups. This is similar to the dispersal pattern found in chimpanzees, bonobos and many human groups, but dissimilar from that of most gorillas and other primates. The small proportion of demonstrably non-local large hominin individuals could indicate that male australopiths had relatively small home ranges, or that they preferred dolomitic landscapes.     

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.     

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.