Search

Copyright of werk, bauen + wohnen is the property of Verlag Werk AG and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Upconversion is a photon-management process especially suited to water-splitting cells that exploit wide-bandgap photocatalysts. Currently, such catalysts cannot utilize 95% of the available solar photons. We demonstrate here that the energy-conversion yield for a standard photocatalytic water-splitting device can be enhanced under solar irradiance by using a low-power upconversion system that recovers part of the unutilized incident sub-bandgap photons. The upconverter is based on a sensitized triplet–triplet annihilation mechanism (sTTA-UC) obtained in a dye-doped elastomer and boosted by a fluorescent nanocrystal/polymer composite that allows for broadband light harvesting. The complementary and tailored optical properties of these materials enable efficient upconversion at subsolar irradiance, allowing the realization of the first prototype water-splitting cell assisted by solid-state upconversion. In our proof-of concept device the increase of the performance is 3.5%, which grows to 6.3% if concentrated sunlight (10 sun) is used. Our experiments show how the sTTA-UC materials can be successfully implemented in technologically relevant devices while matching the strict requirements of clean-energy production.

Colloidal nanoplatelets are atomically flat, quasi-two-dimensional sheets of semiconductor that can exhibit efficient, spectrally pure fluorescence. Despite intense interest in their properties, the mechanism behind their highly anisotropic shape and precise atomic-scale thickness remains unclear, and even counter-intuitive for commonly studied nanoplatelets that arise from isotropic crystal structures (such as zincblende CdSe and lead halide perovskites). Here we show that an intrinsic instability in growth kinetics can lead to such highly anisotropic shapes. By combining experimental results on the synthesis of CdSe nanoplatelets with theory predicting enhanced growth on narrow surface facets, we develop a model that explains nanoplatelet formation as well as observed dependencies on time and temperature. Based on standard concepts of volume, surface and edge energies, the resulting growth instability criterion can be directly applied to other crystalline materials. Thus, knowledge of this previously unknown mechanism for controlling shape at the nanoscale can lead to broader libraries of quasi-two-dimensional materials.

This article describes a study of men’s groups in Switzerland, in which both the official positions of the men’s organizations (N= 40) as well as the opinions of their members (N= 324) are examined using a mixed methods research design. This research strategy revealed significant ideological fault lines within the men’s organizations, ranging from explicitly affirmed anti-feminism to radical profeminist positions. At the same time, the mixed methods approach uncovered the existence of a shared view that transcends these fault lines, a view common to all types of men’s organizations. In light of these findings, the methodological approach used in this study is compared with that employed in the landmark studies of men’s movements from the 1990s.

Funerary taphonomy has come of age as an important field in osteoarchaeology. Its goal is to reconstruct funerary practices by using taphonomic evidence, including both evidence recorded during excavation (particularly the context and state of articulation of human remains) and evidence observable in subsequent laboratory analysis (such as element representation and traces of burning, animal modification, cut-marks, and fragmentation). This article – intended as a systematic introduction to the field – gives an overview of funerary taphonomy. It first discusses the goals and theoretical questions, and then reviews the wide range of methods available to archaeologists using human remains to investigate funerary behaviour. It finishes with a review of how taphonomists have approached particular issues, such as single burials, commingled multiple depositions, cannibalism, and the cultural reuse of human skeletal parts.

During the Neolithic, mortuary practices in the Near East sometimes involved intramural burial and often some type of removal or caching of the bony elements of the head. Reports of defleshing are described in the literature, but there is little published evidence for other surface modifications of human remains. In his 1960s publications on the Neolithic site of Çatalhöyük, James Mellaart proposed that individuals were defleshed by vultures prior to intramural interment. This hypothesis was predominantly based on the discovery of wall paintings of large raptorial birds hovering over headless bodies, coupled with the various states of disarticulation of many of the human remains excavated on site, including ‘headless’ bodies (those missing the cranium and mandible), as well as isolated crania and other skeletal elements. Despite these observations, subsequent osteological analysis has failed to show definitive taphonomic evidence of such practices.

External auditory exostoses (EAEs) are osseous exostoses that form in the external auditory canal as a result of an irritation of the periosteum. Many conditions can be responsible for this irritation, but contact with cold water is the principal cause. This article is a brief review of clinical and anthropological studies that permit consideration of EAEs as faithful markers of water-related activities in past populations and discusses the potential as well as the limits of EAEs to provide insights into aquatic resource exploitation by prehistoric humans.

Die bildgebenden Verfahren sind ein wichtiger diagnostischer Eckpfeiler bei der Abklärung von Beschwerden des Bewegungsapparates. Dank der Entwicklung in den letzten 100 Jahren hat diese Form der Diagnostik enorme Fortschritte gemacht und sie wird sie weiter machen. Dank der Computertechnologie ist es möglich, nicht nur Abbildungsverfahren zu verfeinern und zu beschleunigen, sondern auch Rekonstruktionen herzustellen, die technisch hervorragend sind und für gewisse operative Indikationen notwendig sein können. Diese Entwicklung provoziert jedoch eine Ausgangssituation, die nicht mehr den heutigen Anforderungen der Wirtschaftlichkeit und Zweckmäßigkeit entspricht. Daher ist es Aufgabe jedes Anwenders dieser Techniken, dass er sich bewusst ist, was er von einer solchen Untersuchung erwarten darf, was die Aussage sein soll und wie er die erhaltenen Befunde zu interpretieren hat. Wir müssen uns bewusst sein, dass bildgebende Verfahren allein nicht eintscheidend sind für die Diagnose und den therapeutisch einzuschlagenden Weg. Es ist vielmehr das ganze Bild des Patienten mit klar erhobener Anamnese und klinischer Untersuchung. Durch diese Maßnahmen können ein Großteil der Diagnosen gestellt und eine Behandlung eingeleitet werden. Aufwändige bildgebende Verfahren haben dann einen Sinn und sind notwendig, wenn eine therapierefraktäre Situation vorliegt oder wenn klar Hinweise für eine systemische Erkrankung vorliegen wie Infektionen, Malignome oder Lähmungen.

This paper reports on a study that aims to fill a niche within scientific illustration by developing a method whereby evidence of disease and trauma in archaeological human remains can be translated into a meaningful visual reconstruction of a diseased or physically impaired individual in life. A case study is presented, which involved reconstructing the rhino-maxillary effects of leprosy in an adult male. It is suggested that such reconstruction illustrations could have an important role in communicating ideas both to specialists and particularly to non-specialists, and may also be valuable as research tools in their own right.

Obwohl in der Medizingeschichte die Badekurorte eine wichtige Rolle spielen und in nahezu sämtlichen Kulturkreisen auf der Welt archäologische Funde über Heilquellen und Badekultur bestehen, tut sich die moderne Medizin schwer, die Wirkungen der Balneotherapie zu anerkennen. Wohl gibt es wenig Studien, die gemäß Evidence-based-Medicine durchgeführt wurden. In der Balneologie ist jedoch die empirische Seite überdurchschnittlich wichtig und der Jahrttausend dauernde Gebrauch des Heilwassers ist schon Hinweis genug, dass sich diese Therapieform auch in der technifizierten Welt ihren Stellenwert so behalten darf. Es gibt Studien, die sowohl die spezifische wie unspezifische Wirkung darlegen konnten. Wichtig ist jedoch die Kenntnis des Hausarztes über die Möglichkeiten der Balneotherapie, damit der Patient seine gezielte und individuelle Balneotherapie erhalten kann.

The Romano-British cemetery at Kempston, a suburb of Bedford, was excavated in 1992 by Bedfordshire County Archaeology Service and revealed 12 individuals who had been decapitated and 12 who were placed in the prone position. These practices are a regular feature of internments in rural and a few urban cemeteries dating to the late Roman period in a well-defined area of central England. The osteological findings are discussed and placed in the context of more widespread Iron Age customs.

TYROSINE phosphorylation of trktype neurotrophin receptors in primary cultures of embryonic rat brain cells was studied by immunoprecipitation and immunoblotting. In cultures containing basal forebrain cholinergic neurons, but not in cultures of cerebral cortex, nerve growth factor (NGF) treatment for 4 min induced tyrosine phosphorylation of trkfamily proteins. Stimulation with brain-derived neurotrophic factor (BDNF) or neurotrophin-3 (NT-3), resulted in a very robust phosphorylation signal in basal forebrain and cortical cultures, suggesting actions of these neurotrophins not only on cholinergic cells but probably on most embryonic brain neurons. Trktyrosine phosphorylation was completely abolished by 5 μM K-252b. Inhibition was rapid, being evident by 30 s following addition of the drug. Corresponding stimulatory and inhibitory effects were seen for phospholipase-Cγ1 (PLCγ1) and extracellular signal-regulated kinase 1 (Erk1), two enzymes involved in second messenger mechanisms. Our findings indicate involvement of trkreceptor activation in the NGF response of basal forebrain cholinergic cells and provide evidence for widespread presence of BDNF and NT-3 responsive neurons in the embryonic brain.

To elucidate the role of TGFα as a growth factor in the developing brain and to obtain information on signal transduction mechanisms mediating these effects, we measured the hydrolysis of phosphatidylinositol (PI) in cultures from fetal rat brain cells. Stimulation of PI breakdown induced by TGFα was observed in cultures of mesencephalic cells containing both neuronal and non-neuronal cells, whereas TGFα was ineffective in both pure neuronal and pure glial cultures. These findings are compatible with the view that TGFα plays a role during brain development and that its actions on PI hydrolysis, requires the presence of neuronal and glial cells.

Metabolic compromise with systemic 3-nitropropionic acid (3-NP) results in the degeneration of striatal cells, mimicking the pathology of Huntington's disease (HD). Here we show that 10-week- and 8-month-old BALB/c ByJ mice show an unexpected striatal resilience to single and multiple systemic injections of 3-NP, while Sprague–Dawley rats are vulnerable, albeit in a variable manner. Identification of lesions was made by staining of DNA fragmentation with terminal deoxytransferase-mediated dUTP–biotin nick-end labeling (TUNEL) and hematoxylin/eosin, 1–10 days after injection. Quantitative imaging of histochemistry for succinate dehydrogenase (SDH) activity, the target of 3-NP inhibition, revealed that vulnerable rats reached maximal inhibition in brain at 1 day after 3-NP, whereas mice and resilient rats took 7 days to reach maximal inhibition. All groups of animals reached similar maximal decreases in SDH activity in striatum and cortex. Remarkably, only the fast decline in SDH activity seen in vulnerable rats was associated with TUNEL labeling. In addition, vulnerable rats developed a region within striatum where SDH activity was fully depleted and a similarly depleted region in CA1 hippocampus. While mice did not develop this region in striatum, some developed one in CA1. These regions of SDH depletion in both structures were associated with widespread TUNEL staining, with maximal labeling at 3 days after 3-NP. The existence of an animal strain resilient to 3-NP suggests that there are mediating factors involved in the preferential vulnerability of striatum to metabolic lesioning. The identification of these factors could provide strategies for therapeutic intervention in HD.

The effect of quindoxin on the synthesis of deoxyribonucleic acid (DNA), ribonucleic acid, and protein in Escherichia coliKL 399 was examined under aerobic and anaerobic conditions. In the absence of oxygen the synthesis of DNA was completely inhibited by 10 ppm of quindoxin, whereas the syntheses of ribonucleic acid and protein were not affected. Quinoxalin-di-N-oxides (QdNO) induce degradation of DNA in both proliferating and non-proliferating cells. polA, recA, recB, recC, exrA, and uvrAmutants were more susceptible than the corresponding repair-proficient strains. All strains were more resistant in the presence of oxygen. Quindoxin was reduced to quinoxalin-N-oxide by intact E. colicells or by a cell-free E. coliextract. Electron spin resonance measurements demonstrated the generation of free radicals during the reduction of quindoxin. Oxygen or deficiency of energy sources impaired the antibiotic activity and the reduction of QdNO. The QdNO reductase activity was demonstrated to be lower in QdNO-resistant mutants than in the susceptible parent strain. Based on these results it is concluded that an intermediate of reduction, probably a free radical, is responsible for the lethal effect of quindoxin. With three independent techniques no evidence has been found for binding of quindoxin to DNA.

Recombinant human brain-derived neurotrophic factor (rhBDNF) and neurotrophin 3 (rhNT-3), two recently cloned molecules closely related to nerve growth factor (NGF), were produced from human cDNA expressed in human embryonic kidney cells. The recombinant proteins were tested in cultures of dissociated fetal rat brain cells containing basal forebrain cholinergic neurons. rhBDNF stimulated the differentiation of the cholinergic neurons, similar to NGF, which is well established as a neurotrophic factor for these cells. However, rhBDNF was particularly effective during the first few days in vitro, whereas the stimulatory action of rhNGF was more pronounced later in the development of the cultures. This finding indicates the existence of different time periods of responsiveness of the cholinergic neurons to BDNF and NGF. To assess the selectivity of the effect of rhBDNF on cholinergic neurons, its actions were tested in cultures of ventral mesencephalon containing dopaminergic cells. In contrast to NGF, which does not affect central dopaminergic neurons, rhBDNF increased dopamine uptake activity. The findings suggest that BDNF stimulates survival or differentiation of other cells besides the cholinergic neurons.

Ohne Zusammenfassung: