Experimental evidence for sub-3-fs charge transfer from an aromatic adsorbate to a semiconductor

The ultrafast timescale of electron transfer processes is crucial to their role in many biological systems and technological devices. In dye-sensitized solar cells, the electron transfer from photo-excited dye molecules to nanostructured semiconductor substrates needs to be sufficiently fast to compete effectively against loss processes and thus achieve high solar energy conversion efficiencies. Time-resolved laser techniques indicate an upper limit of 20 to 100 femtoseconds for the time needed to inject an electron from a dye into a semiconductor, which corresponds to the timescale on which competing processes such as charge redistribution and intramolecular thermalization of excited states occur. Here we use resonant photoemission spectroscopy, which has previously been used to monitor electron transfer in simple systems with an order-of-magnitude improvement in time resolution, to show that electron transfer from an aromatic adsorbate to a TiO(2) semiconductor surface can occur in less than 3 fs. These results directly confirm that electronic coupling of the aromatic molecule to its substrate is sufficiently strong to suppress competing processes.     

Direct histochemical demonstration of histamine in cutaneous mast cells: Urticaria pigmentosa and keloids

Zusammenfassung Die Haut von Patienten mit Urticaria pigmentosa und Keloiden wurde mit der histochemischeno-Phthaldialdehyd-Technik untersucht. Die Lokalisation von Histamin konnte durch Fluoreszenzmikroskopie festgestellt werden.     

Crossed reflex actions by low threshold muscle afferents

Zusammenfassung Bei chronisch spinalen Katzen wurde mit Hilfe tetanischer Reizung festgestellt, dass grosse afferente, von Muskeln kommende Fasern gekreuzte Wirkungen auf monosynaptische Reflexe ausüben. Die Ausdehnung der Effekte wird beschrieben.     

Effect of deglycyrrhizinized liquorice on gastric acid secretion,histidine decarboxylase activity and serum gastrin level in the rat

Zusammenfassung Nachweis, dass die Behandlung mit einem deglycyrrhizinierten Lakrizpräparat die basale Säurereaktion bei Ratten hemmt. Erhöhtes antrales pH führt zu vermehrter Freisetzung von antralem Gastrin mit bedeutender Aktivierung der Histidindecarboxylase in der Magenschleimhaut.

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Acknowledgments: This study was supported by the Swedish Medical Research Council No. B73-04x-1007-08 and by the Albert Påhlsson Foundation.     

The Role of the Qualifying Function Concept in Systems Design

In this paper I explore potential benefits with using the concept qualifying function as a tool for systems design. The concept originates from the philosophy of Herman Dooyeweerd and refers to the function or character that guides and directs the internal structure of an entity or activity. This means that if the qualifying function for an entity or activity changes, its structure as a whole will change as well. Due to this, the concept and its related theory can help people to view situations from new and different perspectives and to explore the consequences of different views. It can provide a common base for the design around which accommodation more easily can be reached and from where further discussions can be continued. Finally, it has the potential to point at fundamental differences of opinion between participants and stakeholders.     

Lgr5 marks cycling, yet long-lived, hair follicle stem cells

In mouse hair follicles, a group of quiescent cells in the bulge is believed to have stem cell activity. Lgr5, a marker of intestinal stem cells, is expressed in actively cycling cells in the bulge and secondary germ of telogen hair follicles and in the lower outer root sheath of anagen hair follicles. Here we show that Lgr5(+) cells comprise an actively proliferating and multipotent stem cell population able to give rise to new hair follicles and maintain all cell lineages of the hair follicle over long periods of time. Lgr5(+) progeny repopulate other stem cell compartments in the hair follicle, supporting the existence of a stem or progenitor cell hierarchy. By marking Lgr5(+) cells during trafficking through the lower outer root sheath, we show that these cells retain stem cell properties and contribute to hair follicle growth during the next anagen. Expression analysis suggests involvement of autocrine Hedgehog signaling in maintaining the Lgr5(+) stem cell population.     

SHARPIN forms a linear ubiquitin ligase complex regulating NF-κB activity and apoptosis

SHARPIN is a ubiquitin-binding and ubiquitin-like-domain-containing protein which, when mutated in mice, results in immune system disorders and multi-organ inflammation. Here we report that SHARPIN functions as a novel component of the linear ubiquitin chain assembly complex (LUBAC) and that the absence of SHARPIN causes dysregulation of NF-κB and apoptotic signalling pathways, explaining the severe phenotypes displayed by chronic proliferative dermatitis (cpdm) in SHARPIN-deficient mice. Upon binding to the LUBAC subunit HOIP (also known as RNF31), SHARPIN stimulates the formation of linear ubiquitin chains in vitro and in vivo. Coexpression of SHARPIN and HOIP promotes linear ubiquitination of NEMO (also known as IKBKG), an adaptor of the IκB kinases (IKKs) and subsequent activation of NF-κB signalling, whereas SHARPIN deficiency in mice causes an impaired activation of the IKK complex and NF-κB in B cells, macrophages and mouse embryonic fibroblasts (MEFs). This effect is further enhanced upon concurrent downregulation of HOIL-1L (also known as RBCK1), another HOIP-binding component of LUBAC. In addition, SHARPIN deficiency leads to rapid cell death upon tumour-necrosis factor α (TNF-α) stimulation via FADD- and caspase-8-dependent pathways. SHARPIN thus activates NF-κB and inhibits apoptosis via distinct pathways in vivo.     

Pricing of basket options using univariate normal inverse Gaussian approximations

In this paper we study the approximation of a sum of assets having marginal log‐returns being multivariate normal inverse Gaussian distributed. We analyse the choice of a univariate exponential NIG distribution, where the approximation is based on matching of moments. Probability densities and European basket call option prices of the two‐asset and univariate approximations are studied and analysed in two cases, each case consisting of nine scenarios of different volatilities and correlations, to assess the accuracy of the approximation. We find that the sum can be well approximated, failing, however, to match the tails for some extreme parameter choices. The approximated option prices are close to the true ones, although becoming significantly underestimated for far out‐of‐the‐money call options. Copyright © 2010 John Wiley & Sons, Ltd.     

Basic Principles of SSM Modeling: An Examination of CATWOE from a Soft Perspective

This paper examines the SSM technique CATWOE, which focuses on defining necessary elements that together constitute a human activity system from a certain perspective. Despite its recognition within the literature and its numerous uses, there are few studies on how the technique can be improved. This research reflects on each of the elements both from a theoretical and a practical perspective. Findings point to the fact that some of the terms have a meaning in everyday language that differs from its definition within CATWOE. Other concepts are not well-defined. This is unfortunate and may both lead to misunderstandings and limit analysis. The paper points to a number of ways in which the use of CATWOE can be developed in order to further support the process of eliciting novel ideas for future actions. Hence, the overall conclusion is that the elements need to be rethought and some of them renamed.