The role of metal ions in the electron transport through azurin-based junctions

We studied the coherent electron transport through metal–protein–metal junctions based on a blue copper azurin, in which the copper ion was replaced by three different metal ions (Co, Ni and Zn). Our results show that neither the protein structure nor the transmission at the Fermi level change significantly upon metal replacement. The discrepancy with previous experimental observations suggests that the transport mechanism taking place in these types of junctions is probably not fully coherent

Cavernostomy x Resection for Pulmonary Aspergilloma: A 32-Year History

<p>Abstract</p> <p>Background</p> <p>The most adequate surgical technique for the treatment of pulmonary aspergilloma is still controversial. This study compared two groups of patients submitted to cavernostomy and pulmonary parenchyma resection.</p> <p>Methods</p> <p>Cases of pulmonary aspergilloma operated upon between 1979 and 2010 were analyzed retrospectively. Group 1 consisted of patients submitted to cavernostomy and group 2 of patients submitted to pulmonary parenchyma resection. The following variables were compared between groups: gender, age, number of hospitalizations, pre- and postoperative length of hospital stay, time of follow-up, location and type of aspergilloma, preoperative symptoms, underlying disease, type of fungus, preoperative pulmonary function, postoperative complications, patient progression, and associated diseases.</p> <p>Results</p> <p>A total of 208 patients with pulmonary aspergilloma were studied (111 in group 1 and 97 in group 2). Group 1 was older than group 2. The number of hospitalizations, length of hospital stay and time of follow-up were higher in group 1. Hemoptysis was the most frequent preoperative symptom in group 1. Preoperative respiratory malfunction was more severe in group 1. Hemorrhagic complications and recurrence were more frequent in group 1 and infectious complications and residual pleural space were more common in group 2. Postoperative dyspnea was more frequent in group 2. Patient progression was similar in the two groups. No difference in the other factors was observed between groups.</p> <p>Conclusions</p> <p>Older patients with severe preoperative respiratory malfunction and peripheral pulmonary aspergilloma should be submitted to cavernostomy. The remaining patients can be treated by pulmonary resection.</p

Reversible Modulation of Spontaneous Emission by Strain in Silicon Nanowires

We computationally study the effect of uniaxial strain in modulating the spontaneous emission of photons in silicon nanowires. Our main finding is that a one to two orders of magnitude change in spontaneous emission time occurs due to two distinct mechanisms: (A) Change in wave function symmetry, where within the direct bandgap regime, strain changes the symmetry of wave functions, which in turn leads to a large change of optical dipole matrix element. (B) Direct to indirect bandgap transition which makes the spontaneous photon emission to be of a slow second order process mediated by phonons. This feature uniquely occurs in silicon nanowires while in bulk silicon there is no change of optical properties under any reasonable amount of strain. These results promise new applications of silicon nanowires as optoelectronic devices including a mechanism for lasing. Our results are verifiable using existing experimental techniques of applying strain to nanowires

Aspectos tomográficos do tumor estromal gastrintestinal de origem gástrica: estudo de 14 casos Tomographic findings of gastric gastrointestinal stromal tumor: a 14-case study

OBJETIVO: Descrever os achados tomográficos do tumor estromal gastrintestinal de origem gástrica. MATERIAIS E MÉTODOS: No período de janeiro de 1999 a dezembro de 2006, foram selecionados 14 pacientes com diagnóstico histopatológico e imuno-histoquímico de tumor estromal gastrintestinal gástrico que apresentavam tomografia computadorizada realizada anteriormente ao tratamento. As variáveis tomográficas analisadas foram: topografia da lesão, dimensões, homogeneidade, contornos, limites, morfologia, padrão e intensidade do realce pelo meio de contraste venoso, padrão de crescimento, invasão de órgãos adjacentes, presença de ulceração, fístula, calcificações, infiltração da gordura mesentérica, linfonodomegalias e metástases a distância. RESULTADOS: Os tumores foram localizados no corpo (57,1%) ou fundo gástrico (42,9%), com dimensões variando entre 6,0 e 23,0 cm (média de 11,5 cm). O crescimento foi predominantemente extraluminal (57,1%) ou intra/extraluminal (35,7%). O realce pelo contraste venoso foi discreto em 50% dos casos, moderado em 50% e heterogêneo em 64,3%. Foram ainda observadas hipodensidade central em 64,3% dos casos, invasão de órgãos adjacentes em 42,9% e metástases hepáticas em 7,2%. CONCLUSÃO: No presente estudo, a maioria dos tumores localizava-se no corpo gástrico, com tamanho médio de 11,5 cm, apresentando área hipodensa central, realce heterogêneo pelo meio de contraste e crescimento predominantemente extraluminal.<br>OBJECTIVE: The purpose of this study was to describe the tomographic findings of gastric gastrointestinal stromal tumor. MATERIALS AND METHODS: Fourteen patients with histopathologically and immunohistochemically confirmed gastric gastrointestinal stromal tumors, who had already been submitted to computed tomography scans before the treatment, were evaluated in the period between January 1999 and December 2006. The following tomographic variables were analyzed: lesion topography, size/dimensions, homogeneity, contour, margins, morphology, pattern and intravenous contrast-enhancement intensity, growth pattern, invasion of adjacent organs, presence of ulceration, fistula, calcifications, mesenteric fat infiltration, lymphadenomegaly and presence of distant metastasis. RESULTS: Tumors were found in the body (57.1%) or in the gastric fundus (42.9%), with sizes ranging between 6.0 cm and 23.0 cm (mean, 11.5 cm). Predominantly extraluminal growth was observed in 57.1% of cases and intra/extraluminal in 35.7%. Subtle contrast-enhancement was observed in 50%, moderate in 50%, and heterogeneous in 64.3% of cases. Additionally, central hypodensity was observed in 64.3%, invasion of adjacent organs in 42.9%, and hepatic metastasis in 7.2% of cases. CONCLUSION: In the present study, the majority of tumors were found in the gastric body, with an average size of 11.5 cm, presenting with central hypodensity, heterogeneous contrast-enhancement and predominantly extraluminal growth