Depth-Sensing Indentation on REBa2Cu3O(7-\delta) Single Crystals obtained from Xenotime Mineral

A natural mixture of heavy rare earths oxides extracted from xenotime mineral have been used to prepare large single crystals of high-temperature REBa2Cu3O(7-\delta) superconductor grown using the CuO-BaO self-flux method. Its mechanical properties along the ab-plane were characterized using instrumented indentation. Hardness and elastic modulus were obtained by the Oliver and Pharr method and corresponds to 7.4 \pm 0.2 GPa and in range 135-175 GPa at small depths, respectively. Increasing the load promotes the nucleation of lateral cracks that causes a decrease in hardness and the measured elastic modulus by instrumented indentation at higher loads. The indentation fracture toughness was estimated by measuring the radial crack length from cube-corner indentations at various loads and was 0.8 \pm 0.2 MPa.m1/2. The observed slip systems of REBa2Cu3O(7-\delta) single crystals were [100](001) and [010](001), the same as for YBa2Cu3O(7-\delta) single crystals. The initial stages of deformation and fracture in the indentation process were investigated. The hardness and elastic modulus were not strongly modified by the crystallographic orientation in the ab-plane. This was interpreted in terms of the resolved shear stresses in the active slip systems. Evidence of cracking along the {100} and {110} planes on the ab-plane was observed. As a conclusion, the mechanical properties of REBa2Cu3O(7-\delta) single crystals prepared from xenotime are equivalent to those of YBa2Cu3O(7-\delta) single crystals produced by conventional rare earths oxides.Comment: The paper will appear in Volume 42 (2012) of the Brazilian Journal of Physic

Sindrome disfágica Dysphagic syndrome

INTRODUÇÃO: A disfagia é o principal sintoma das doenças do esôfago e é representada pela dificuldade em deglutir o alimento ingerido no trajeto da orofaringe até o estômago. Ela é queixa comum na prática clínica diária envolvendo várias especialidades na sua investigação. MÉTODOS: Foi realizada revisão atualizada da literatura internacional através do Pubmed (www.pubmed.com) e nacional (www.lilacs.br) utilizando-se as seguintes palavras-chave: disfagia e transtornos da deglutição. A extensão do tema foi limitado aos seguintes enfoques: etiologia, diagnóstico e exames complementares mais aplicáveis à exploração propedêutica. CONCLUSÃO: Embora a literatura apresente bom entendimento do processo disfágico, no diagnóstico preciso de sua causa há freqüentemente necessidade de múltiplos exames complementares que associados fazem melhor entender o que acomete o paciente e orientará mais adequadamente a conduta a ser tomada<br>BACKGROUND: Dysphagia is the main symptom of diseases of the esophagus, being manifested by deglutition difficulties, which reaches the oropharynx and stomach pathway. Is a common daily complaint in the clinical practice, involving numerous specialties regarding its investigation. METHODS: An international literature review was made using Pubmed (www.pubmed.com) and a national utilizing (www.lilacs.br) the following keywords: dysphagia and deglutition disorders. The extension of the subject was limited to the following areas: etiology, diagnosis and complementary exams which were aplicable to exploratory propedeutics. CONCLUSION: Eventhough the literature presents a good understanding of the dysphagic process, the need for multiple complementary exams is frequent during diagnosis, developing a better understanding of what the patient has, adequately orienting which conduct should be taken

Barrett's esophagus: surgical treatments.

The following on surgical treatments for Barrett's esophagus includes commentaries on the indications for antireflux surgery after medical treatment; the effects of the various procedures on the lower esophageal sphincter; the role of impaired esophageal motility and delayed gastric emptying in the choice of the surgical procedure; indications for associated highly selective vagotomy, duodenal switch, and gastric electrical stimulation; therapeutic strategies for detection and treatment of shortened esophagus; the role of antireflux surgery on the regression of metaplastic mucosa and the risk of malignant progression; the detection of asymptomatic reflux brfore bariatric surgery; the role of non-GERD symptoms on the results of surgery; and the indications of Collis gastroplasty and choice of the type of fundoplicatio

Surgical treatments for esophageal cancers

The following, from the 12th OESO World Conference: Cancers of the Esophagus, includes commentaries on the role of the nurse in preparation of esophageal resection (ER); the management of patients who develop high‐grade dysplasia after having undergone Nissen fundoplication; the trajectory of care for the patient with esophageal cancer; the influence of the site of tumor in the choice of treatment; the best location for esophagogastrostomy; management of chylous leak after esophagectomy; the optimal approach to manage thoracic esophageal leak after esophagectomy; the choice for operational approach in surgery of cardioesophageal crossing; the advantages of robot esophagectomy; the place of open esophagectomy; the advantages of esophagectomy compared to definitive chemoradiotherapy; the pathologist report in the resected specimen; the best way to manage patients with unsuspected positive microscopic margin after ER; enhanced recovery after surgery for ER: expedited care protocols; and long‐term quality of life in patients following esophagectomy