999 resultados para Canal de ondas


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Avalanche hazard maps of high accuracy are difficult to produce. For land-use planning and management purposes, a good knowledge of extreme run-out zones and frequencies of avalanches is required. In the present work, vegetation recognition (especially focused on Pinus uncinata trees) and dendrochronological techniques are used to characterize avalanches that have occurred in historical times, helping to determine both the extent of large or extreme avalanches and their occurrence in time. Vegetation was studied at the Canal del Roc Roig (eastern Pyrenees, Spain) avalanche path. The avalanches descending this path affect the railway that reaches the Vall de Núria resort and the run-up to the opposite slope. During winter 1996, two important avalanches affecting this path were well documented. These are compared with the results of the vegetation study, consisting of an inventory of flora, the recording of vegetation damages along eight transverse profiles at different altitudes on the path and a dendrochronological sampling campaign. The data obtained contributed to a characterization of the predominant snow accumulation in the starting zone, the 1996 avalanches and the range of frequencies of large avalanches. Also, traces of avalanches that increase the path mapped in the avalanche paths map published by the Institut Cartogràfic de Catalunya in 2000 were identified, improving the initial existing information.

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Avalanche hazard maps of high accuracy are difficult to produce. For land-use planning and management purposes, a good knowledge of extreme run-out zones and frequencies of avalanches is required. In the present work, vegetation recognition (especially focused on Pinus uncinata trees) and dendrochronological techniques are used to characterize avalanches that have occurred in historical times, helping to determine both the extent of large or extreme avalanches and their occurrence in time. Vegetation was studied at the Canal del Roc Roig (eastern Pyrenees, Spain) avalanche path. The avalanches descending this path affect the railway that reaches the Vall de Núria resort and the run-up to the opposite slope. During winter 1996, two important avalanches affecting this path were well documented. These are compared with the results of the vegetation study, consisting of an inventory of flora, the recording of vegetation damages along eight transverse profiles at different altitudes on the path and a dendrochronological sampling campaign. The data obtained contributed to a characterization of the predominant snow accumulation in the starting zone, the 1996 avalanches and the range of frequencies of large avalanches. Also, traces of avalanches that increase the path mapped in the avalanche paths map published by the Institut Cartogràfic de Catalunya in 2000 were identified, improving the initial existing information.

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One hundred twenty-two early-stage anal canal cancer patients (median age: 69 years) were treated with curative radiotherapy with (70 patients) or without (52 patients) concomitant chemotherapy. Median follow-up was 65 months (range: 4-238). At multivariate analysis, concomitant chemotherapy significantly improved local control (p = .007). Local control significantly influenced all considered endpoints, except the metastases free survival. The global rates of G3-G4 acute and late toxicity were 13.1% and 8.2%, respectively, and they were not increased by concomitant chemotherapy. Finally, concomitant chemotherapy is efficacious and safe in the treatment of T1-2N0 anal canal cancer patients and should be prospectively studied.

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AIMS AND BACKGROUND: The standard treatment of anal canal cancer (ACC) is combined chemotherapy and radiation therapy (RT), which is complex because of the shape of the target volumes and the need to minimize the irradiation of normal pelvic structures. In this study we compared the dosimetric results of helical tomotherapy (HT) plans with traditional 3D conformal RT (3DRT) plans for the treatment of ACC. METHODS AND STUDY DESIGN: Twelve patients (median age 57 years, range 38-83; F/M 8/4) treated with HT and concurrent chemotherapy for locally advanced ACC were selected. All had histologically confirmed squamous-cell carcinoma. A clinical target volume including the tumor and pelvic and inguinal lymph nodes was treated with HT to a total dose of 36 Gy in 1.8-Gy daily fractions. Then a sequential boost of 23.4 Gy in 1.8-Gy daily fractions (total dose 59.4 Gy) was delivered to the tumor and involved nodes. For all 12 patients, 3DRT plans were generated for comparison. Treatment plans were evaluated by means of standard dose-volume histograms. Dose coverage of the planning target volumes (PTVs), homogeneity index (HI), and mean doses to organs at risk (OARs) were compared. RESULTS: The coverage of PTV was comparable between the two treatment plans. HI was better in the HT vs. 3DRT plans (1.25 and 3.57, respectively; p<0.0001). HT plans resulted in better sparing of OARs (p<0.0001). CONCLUSIONS: HT showed superior target dose conformality and significant sparing of pelvic structures compared with 3DRT. Further investigation should determine if these dosimetric improvements will improve clinical outcomes regarding locoregional control, survival, and treatment-related acute and late morbidity.

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BACKGROUND AND PURPOSE: There are few data on long-term clinical results and tolerance of brachytherapy in anal canal cancer. We present one of the largest retrospective analyses of anal canal cancers treated with external beam radiotherapy with/without (±) chemotherapy followed by a brachytherapy boost. MATERIALS AND METHODS: We performed a retrospective analysis of clinical results in terms of efficacy and toxicity. The impact of different clinical and therapeutic variables on these outcomes was studied. RESULTS: From May 1992 to December 2009, 209 patients received brachytherapy after external beam radiotherapy ± chemotherapy. Of these patients, 163 were stage II or stage IIIA (UICC 2002) and 58 were N1-3. According to age, ECOG performance status (PS), and comorbidities, patients received either radiotherapy alone (58/209) or radiochemotherapy (151/209). The median follow-up was 72.8 months. The 5- and 10-year local control rates were 78.6 and 73.9 %, respectively. Globally, severe acute and late G3-4 reactions (NCI-CTC scale v. 4.0) occurred in 11.2 and 6.3 % of patients, respectively. Univariate analysis showed the statistical impact of the pelvic treatment volume (p = 0.046) and of the total dose (p = 0.02) on the risk of severe acute and late toxicities, respectively. Only six patients required permanent colostomy because of severe late anorectal toxicities. CONCLUSION: After a long follow-up time, brachytherapy showed an acceptable toxicity profile and high local control rates in patients with anal canal cancer.

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El objetivo de estos programas es crear una herramienta que nos permita, de una manera fácil, entender mejor la separación de fuentes y la deconvolución de canal . Por eso se presenta el diseño, mediante Java, de una página web [1]: http//www.uvic.es/projectes/SeparationSources con carácter marcadamente didáctico para el estudio y evaluación de diferentes algoritmos propuestos en la bibliografía.

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Os autores apresentam o caso de paciente do sexo masculino, 62 anos de idade, com emagrecimento há quatro meses e diminuição da força muscular associada a parestesias em membros inferiores há dois dias. Foi submetido a mielotomografia, que demonstrou massa no mediastino posterior com destruição dos corpos vertebrais e invasão do canal medular, além de espessamento irregular das paredes do esôfago. Na evolução, foi submetido a estudo contrastado do esôfago, que demonstrou falha de enchimento irregular. A biópsia confirmou a presença de carcinoma de células escamosas. Este é o primeiro relato na literatura latino-americana (Lilacs) de carcinoma de esôfago com invasão de canal medular e manifestação inicial de síndrome de compressão medular.

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A partir del análisis del modo fundamental de las ondas Rayleigh generadas por tres terremotos situados en las Azores, Sicilia y el Mar Negro se obtiene la variación regional del coeficiente de atenuación en el escudo europeo para un intervalo de periodos de 15-80 s. El método de análisis ha consistido en comparar los espectros de amplitudes observados con los calculados teóricamente. Para el calculo de estos últimos se ha utilizado un nuevo método consistente en calcular la función global de la fuente a partir de un proceso de mínimos cuadrados. Los resultados son los siguientes.

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We present a retrospective study on 22 operations of exostosis of the external auditory canal in 20 patients. 8 patients were passionated by water sports. The most frequent indication for surgery (13 operations) was recurrent external otitis or ceruminal obstruction. In 7 cases the need for a wider access to the middle ear indicated surgery. Surgery was usually performed as an outpatient procedure, maximum hospitalization was 3 days. The mean healing period was 6 (3-10) weeks. Mean follow up was 43 (3-110) months. There were no severe intraoperative complications such as facial paresis, lesions of the ossicles or of the inner ear. As intraoperative complications we found 2 perforations of the tympanic membrane, 2 expositions of the capsule of the mandibular joint, one of which was followed by chronic pain. As postoperative complications we found an early soft tissue stenosis of the external auditory canal and one late soft tissue stenosis which recurred after revision surgery. No recurrence of exostosis was seen. We describe an up to now unknown complication: the appearance of bilateral petrositis caused by staphylococcus epidermidis after bilateral surgery in an otherwise healthy patient. This study confirms that severe complications are rare, minor ones however relatively common. And that also minor complications may have a troublesome follow. Therefore and because of the potential of severe complications indication for surgery must be made cautiously and risks of the operation must not be underestimated.

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Les WNK kinases sont une famille de sérine/thréonine protéines kinases, des enzymes capables de phosphoryler le résidu OH de sérine ou thréonine. Quatre membres (WNK 1-4) ont été identifiés, largement distribués dans les cellules et tissus des mammifères et dont les fonctions sont de réguler des canaux ioniques et cotransporteurs. Leur particularité se situe au niveau de leur structure puisque une lysine a été substituée par une cystéine dans le domaine catalytique, d'où leur nom « with-no-lysine kinase » (McCormick and Ellison, 2011). Leur rôle dans le bon fonctionnement du rein et plus particulièrement dans le contrôle et maintien du bilan hydro-sodé n'est plus à vérifier puisque des mutations dans WNK 1 et WNK 4 sont connues pour causer la maladie de l'hypertension familiale ou syndrome de pseudohypoaldostéronisme de type 2, aussi appelé syndrome de Gordon (ou Fhht = Familial hyperkalaemic hypertension) (Furgeson and Linas, 2010). Le syndrome de Gordon est une maladie génétique autosomale dominante caractérisée par une hypertension, une hyperkaliémie et une acidose métabolique. Les WNKs contrôlent de nombreux canaux et transporteurs dans le rein, devenant des acteurs importants dans la régulation du bilan sodique et potassique. Leurs effets sont nombreux et variables et les canaux jouant un rôle clé dans cette régulation sont ENaC, NCC et ROMK (Kahle et al., 2008). Dans ce travail, nous commencerons par une partie théorique faisant le point sur l'organisation des néphrons et la régulation du bilan sodique et les différents mécanismes entrant en jeu. Nous intégrerons des informations générales concernant les WNKs ainsi qu'une revue plus détaillée de leurs effets respectifs dans le néphron. Pour terminer, nous aborderons les résultats d'une expérience qui a été réalisée en laboratoire sur des oocytes de Xenopus laevis. L'implication de WNK1 et WNK4 dans le contrôle du sodium ayant déjà été prouvée à de nombreuses reprises, nous nous sommes intéressés ici aux effets de WNK3 sur le canal ENaC ainsi que l'implication de Nedd4-2 dans ce procédé.

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The optimization of a traditional technique of cellular disruption by abrasion was carried out and a process using ultrasonic waves associated with glass pearls to extract beta-galactosidase from Kluyveromyces marxianus proposed. In the first case, the effects of the diameter and weight of the pearls in relation to the volume of cellular suspension and amount of time for cellular disruption were evaluated. The efficiency of the new process of cellular disruption was evaluated by varying the length of time of sonification and comparing with the method of abrasion under the same conditions. The proposed method can be efficiently applied to obtain beta-galactosidase at laboratory scale.

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Many theories about the mechanism of action of local anesthetics (LA) are described in the literature. Two types of theories can be distinguished: those that focus on the direct effects of LA on their target protein in the axon membranes, i.e. the voltage-gated sodium channel and the ones that take into account the interaction of anesthetic molecules with the lipid membrane phase for the reversible nerve blockage. Since there is a direct correlation between LA hydrophobicity and potency, it is crucial to take this physico-chemical property into account to understand the mechanism of action of LA, be it on the sodium channel protein, lipid(s), or on the whole membrane phase.

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This paper proposes a methodology for spectrophotometric determination of hexamethylenetetramine (HMT) by using chromotropic acid in a phosphoric acid media employing a domestic microwave oven as a source of heating. The reddish-purple soluble product is quantitatively formed after 30 s of irradiation and obeys the Beer´s law in the range between 0.1-1.2 mg L-1 HMT (r = 0.99925). The method was applied successfully in commercial pharmaceutical preparations containing dyes in their composition. The results showed that the method proposed is feasible for simplicity, speed, low cost, precision and accuracy when compared with United States Pharmacopeia official method.