Revealing tunnelling details by normalized differential conductance analysis of transport across molecular junctions.

This paper presents the use of normalized differential conductance (NDC) for exploring the effect of applied voltage on charge tunnelling across molecular junctions. It shows the power of NDC in revealing subtle features characteristic of specific tunnelling models and considers its theoretical basis in view of the Taylor-expansion (parabolic approximation) for tunnelling. A practical application of NDC is illustrated by analyzing the current-voltage relations across a short alkyl-thiol monolayer on smooth compared with rough Ag substrates.

Síndrome de Wolfram / Wolfram syndrome

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Treatment of psoriasis with light and heat energy (LHE): a preliminary study.

In psoriasis the earliest observable electron microscopic changes are in the papillary dermis vasculature. Selective photothermolysis of the dermal vasculature using a 585-nm pulsed-dye laser (PDL) for the treatment of psoriasis was reported more than a decade ago. Although clinically effective, the pulsed-dye laser has limited practicality because of small spot size (5-10 mm) and lack of cost effectiveness. The objective of this study is to evaluate the safety and efficacy of a novel Light and Heat Energy (LHE) selective-photothermolysis system for the treatment of psoriasis. This system delivers controlled heat simultaneously with the light pulse; it has a large beam spot (55 x 22 mm) and is sufficiently cost effective to be widely used. Thirteen patients, seven with plaque psoriasis, five with palmoplantar psoriasis, and one with guttate psoriasis participated in a controlled study. Patients received two therapy regimens in parallel: LHE plus salicylic acid or salicylic-acid cream alone as control. Treatments were applied twice weekly spread evenly over 4-6 weeks. In most cases a fluence of 8.6 J/cm2 was applied. Efficacy of the treatment was assessed using the psoriasis-severity index (PSI) calculated from the investigator's overall assessment of the plaque's erythema, scaling, and induration. PSI was evaluated at baseline, at every other treatment visit, and during two follow-up visits scheduled 1 and 5 weeks following the last treatment. In eleven patients who completed the treatment regimen, the average global PSI score for the treated sites was reduced by 65 percent. In contrast, the control sites average global PSI score was reduced by only 7.4 percent. Six patients (55 %) had a significant improvement of 70-percent reduction or above in their PSI score, ten patients (91 %) had a 50 percent or above reduction; only one patient had a poor response (12.5 % reduction in global PSI). Erythema was reported in all cases and resolved within 24-48 hours. Six cases of burns were resolved within 2 days to 2 weeks following appropriate remedy. No cases of dyspigmentation were encountered. Light and Heat Energy (LHE) selective photothermolysis combined with salicylic acid appears to be a practical modality for the treatment of mild to moderate psoriasis. Patients experience discomfort that is only mild. There is no convalescence downtime. Clinical results obtained are similar to those reported with the pulsed-dye laser; however, this new system seems more suitable to be widely adopted as a treatment modality. Further followup is required to determine whether remission periods will be as long as those reported for treatment with the pulsed-dye laser.

[Emergency landing due to a passanger with chest pain, dyspnea, and vomiting]. / Notlandung wegen Thoraxschmerz, Dyspnoe und Erbrechen.

A 20-year old student had suffered since 3 years from diabetes mellitus type I, which was well-controlled by insulin-pump therapy. During a flight from Moscow to Los Angeles, the student all of a sudden had chest pain, dyspnea, and he vomitted repetitively--emergency landing at Zurich airport was necessary. The student presented at the emergency unit in a poor general condition with tachypnea (32/min) and tachycardia (136/min). Arterial blood gas analysis showed severe metabolic acidosis (pH 7.04), while pulmonary or cardiac disease could be ruled out. Diabetic ketoacidosis was caused by the pump running short of insulin. Treatment included rehydration and administration of insulin. Administration of insulin by an insulin-pump allows to continuously and flexibly adjust the dosage according to the requirement of the body. Interruption of insulin administration can cause, however, relatively fast ketoacidosis because exclusively short-acting insulin is used.

Global connections in a changing world: Romanian and U.S. nurses unite.

This article describes an international, interdisciplinary, university partnership project to collaborate with health professionals in the city of Cluj-Napoca, Transylvania, Romania, to improve the health status of Romanian workers. Academic and service-based public health nurses from the United States used the model of community competence in outlining the nursing aspect of the project. This model guided the assessment, objectives, collaborative activities, and the outcome evaluation of the project. The dimensions of the model (e.g., commitment, self-other awareness, articulateness, conflict accommodation, management of relations with larger society, and leadership) were used within the context of the political and social environment of the international community.

Molecular control over Au/GaAs diodes

The use of molecules to control electron transport is an interesting possibility, not least because of the anticipated role of molecules in future electronic devices. But physical implementations using discrete molecules are neither conceptually simple nor technically straightforward (difficulties arise in connecting the molecules to the macroscopic environment). But the use of molecules in electronic devices is not limited to single molecules, molecular wires or bulk material. Here we demonstrate that molecules can control the electrical characteristics of conventional metal-semiconductor junctions, apparently without the need for electrons to be transferred onto and through the molecules. We modify diodes by adsorbing small molecules onto single crystals of n-type GaAs semiconductor. Gold contacts were deposited onto the modified surface, using a 'soft' method to avoid damaging the molecules. By using a series of multifunctional molecules whose dipole is varied systematically, we produce diodes with an effective barrier height that is tuned by the molecule's dipole moment. These barrier heights correlate well with the change in work function of the GaAs surface after molecular modification. This behaviour is consistent with that of unmodified metal-semiconductor diodes, in which the barrier height can depend on the metal's work function.

Imaging supramolecular aggregates in bile models and human bile.

Investigation of cholesterol crystallization is essential for the understanding of gallstone formation. Previous work has revealed a variety of aggregates of different sizes and shapes prior to the appearance of "classical" plate-like cholesterol monohydrate crystals both in native biles and model systems. In this article, we review existing data based on various microscopic techniques and present data on microstructural pathways leading to cholesterol crystal formation in two different bile models and in native bile. In continuation of our recent investigation of microstructures in nucleating human bile, we now present data suggesting that polymorphism is not limited to complex native bile, but also appears in two, simplified model systems. These studies employed cryo-transmission electron microscopy (cryo-TEM) and video-enhanced light microscopy, using Nomarski optics (VELM). Only the combined use of these two complementary, non-perturbing direct methods can cover the whole range of microstructures ranging from a few nanometers to several microns. Concentrated isotropic solutions of bile models, composed of cholesterol, lecithin and taurocholate, were diluted to induce cholesterol supersaturation and start an evolution of microstructures, leading to cholesterol crystallization. Initially, small spheroidal micelles were observed by cryo-TEM. Subsequently, uni-, oligo- and multilamellar vesicles, compatible with structures seen at the same time by VELM, appeared in coexistence with micelles. Thereafter, during a dynamic phase of cholesterol crystallization, filaments, tubular and helical microstructures, as well as classical plate-like cholesterol monohydrate crystals were noted by light microscopy. Eventually, large plate-like crystals were observed by VELM, while cryo-TEM revealed only small spheroidal micelles. The crystallization process in native human bile during ex vivo incubation was found to bear close resemblance to the findings in the model systems, further supporting the applicability of these systems to the exploration of microstructural aspects of nucleating human bile.