Acoustic phonon exchange, attractive interactions, and the Wentzel-Bardeen singularity in single-wall nanotubes

We derive the effective low-energy theory for interacting electrons in metallic single-wall carbon nanotubes taking into account acoustic phonon exchange within a continuum elastic description. In many cases, the nanotube can be described as a standard Luttinger liquid with possibly attractive interactions. We predict surprisingly strong attractive interactions for thin nanotubes. Once the tube radius reaches a critical value $R_0 \approx 3.6\pm 1.4$ \AA, the Wentzel-Bardeen singularity is approached, accompanied by strong superconducting fluctuations. The surprisingly large $R_0$ indicates that this singularity could be reached experimentally. We also discuss the conditions for a Peierls transition due to acoustic phonons.Comment: 11 pages, 2 figures, final version to be published in Phys. Rev.

IgE allergy diagnostics and other relevant tests in allergy, a World Allergy Organization position paper

Currently, testing for immunoglobulin E (IgE) sensitization is the cornerstone of diagnostic evaluation in suspected allergic conditions. This review provides a thorough and updated critical appraisal of the most frequently used diagnostic tests, both in vivo and in vitro. It discusses skin tests, challenges, and serological and cellular in vitro tests, and provides an overview of indications, advantages and disadvantages of each in conditions such as respiratory, food, venom, drug, and occupational allergy. Skin prick testing remains the first line approach in most instances; the added value of serum specific IgE to whole allergen extracts or components, as well as the role of basophil activation tests, is evaluated. Unproven, non-validated, diagnostic tests are also discussed. Throughout the review, the reader must bear in mind the relevance of differentiating between sensitization and allergy; the latter entails not only allergic sensitization, but also clinically relevant symptoms triggered by the culprit allergen

Orientação aos familiares em UTI: dificuldades ou falta de sistematização?

Este estudo teve por objetivo analisar a problemática vivenciada pelos enfermeiros, por ocasião da orientação aos pacientes e familiares, em uma UTI de Clínica Médica. Assim, foram entrevistadas 7 (sete) enfermeiras dessa Unidade, pertencente a um hospital geral, público e de ensino do município de São Paulo. A análise dos resultados evidenciou que o momento de orientação é gerador de tensão e ansiedade para as enfermeiras, tanto pelo estado crítico do paciente, como pela falta de conduta e de sistematização dessa atividade na Unidade. Com base nos resultados, foi proposta a criação de um plano de assistência que inclua a orientação do paciente e família e a elaboração de um instrumento de orientação escrito.The purpose of this study was to analyse the problematic situation experienced by nurses at the moment of guiding the relatives of patients in an ICU. Therefore, seven (7) nurses who worked in this unit, which belonged to a general, public and Craning hospital in the city of São Paulo, were interviewed. The results have shown that the period of guiding brings anxiety and stress to the nurses, originated by the critical patient's condition, as well by' the deficiency of conduts and in the systematization of this activity in the unit. Based on the results it was proposed the creation of na assistance plan. That includes the guiding to the family and the elaboration of a written instrument of orientation