10,866 research outputs found

    Comparación de la eficacia y seguridad diagnóstica entre el estudio isotópico hepatobiliar y la ecografía en la colecistitis aguda

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    Hemos estudiado en 67 pacientes con el diagnóstico de colecistitis aguda (CA) confirmado mediante intervención quirúrgica precoz, la sensibilidad diagnóstica del estudio isotópico con HIDA comparándola con la de la ecografía. El estudio se llevó a cabo de forma retrospectiva. La sensibilidad del estudio isotópico (97%) ha sido claramente superior a la de la ecografía (82%), aunque esta última ofrece ventajas en cuanto a la rapidez y economía de valor indudable. Asimismo hemos intentado establecer la seguridad de ambas técnicas en el diagnóstico de la coledocolitiasis asociada a la CA, que en nuestro estudio ha mostrado una incidencia alta (26%), siendo mala para ambas técnicas; la sensibilidad en este caso para la ecografía ha sido del 50% mientras que para el HIDA ha sido del 12,5%. Por tanto creemos conveniente realizar como primer estudio diagnóstico para la confirmación de la sospecha clínica de CA una ecografía abdominal, reservando la escintigrafía para los casos, por otra parte numéricamente apreciables, en que persista la duda diagnóstica. Asimismo recomendamos la realización de colangiografía intraoperatoria debido a la deficiente fiabilidad que ambas exploraciones han demostrado en la detección de coledocolitiasis en los pacientes con C

    Serum 25-hydroxyvitamin D levels in patients with Granulomatosis with Polyangiitis: association with respiratory infection

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    OBJECTIVES: To determine the possible association of serum 25-hydroxyvitamin D (25OHD) levels with disease activity and respiratory infection in granulomatosis with polyangiitis patients during two different periods: winter/spring and summer/autumn. METHODS: Thirty-two granulomatosis with polyangiitis patients were evaluated in the winter/spring, and the same patients (except 5) were evaluated in summer/autumn (n=27). The 25OHD levels were measured by radioimmunoassay. Disease activity was assessed by the Birmingham Vasculitis Activity Score Modified for Wegener’s Granulomatosis (BVAS/WG) and antineutrophil cytoplasmic antibody (ANCA) positivity. Respiratory infection was defined according the Centers for Disease Control and Prevention criteria. RESULTS: 25OHD levels were lower among patients in winter/spring than in summer/autumn (32.31±13.10 vs. 38.98±10.97 ng/mL, p=0.04). Seven patients met the criteria for respiratory infection: 5 in winter/spring and 2 in summer/autumn. Patients with respiratory infection presented lower 25OHD levels than those without infection (25.15±11.70 vs. 36.73±12.08 ng/mL, p=0.02). A higher frequency of low vitamin D levels (25OH

    Tuning the ionic character of sodium dodecyl sulphate via counter-ion binding: an experimental and computational study

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    Solutions of surfactants exhibit remarkable features, such as a tunable amphiphilic character, which can further be varied for ionic surfactants through variations in their Coulombic interactions. These properties are very useful in many industrial applications such as in extraction, purification, and formulation processes, as detergents, wetting agents, or emulsifiers. Rather unexpectedly, the addition of tetrabutylammonium chloride ([N4,4,4,4]Cl) to solutions of the ionic surfactant of sodium dodecyl sulphate (SDS) results in the appearance of a phase transition above the lower critical solution temperature (LCST), a property usually associated with non-ionic surfactants. The aim of this study is to provide a detailed nanoscopic scenario on the interaction between SDS micelles and [N4,4,4,4]Cl moieties to better understand the nature of the LCST cloud point and how to confer it to a given ionic surfactant system. A coarse-grained molecular dynamics (CG-MD) computational framework, under the latest MARTINI 3.0 force field, was developed and validated using available literature data. The impact of [N4,4,4,4]Cl concentration in the phase of SDS micellar aqueous solutions was then characterized and compared using experimental results. Specifically, dynamic light scattering (DLS) measurements and small-angle X-ray scattering (SAXS) profiles were obtained at different [N4,4,4,4]+/[DS]- molar ratios (from 0.0 to 1.0) and compared with the CG-MD results. A good agreement between computer simulations and experimental findings was obtained, reinforcing the suitability of GC-MD to simulate complex phase behaviors. When the [N4,4,4,4]+/[DS]- molar ratio is 0.5, the system yielded clusters of enclosed small [DS]- aggregates. Thus, the CG-MD simulations showed the formation of mixed [DS]- and [N4,4,4,4]+ aggregates with [N4,4,4,4]+ cations acting as a bridge between small [DS]- micelles. The CG-MD simulation framework developed in this work captured the role of [N4,4,4,4]+ in the micellar phase transition whilst improving the results obtained with preceding computer models for which the limitations on capturing SDS and [N4,4,4,4]Cl mixtures in aqueous solutions are also shown in detail.publishe

    Entrenamiento de las señales corticales a través de un sistema BMI-EEG, evolución e intervención. A propósito de un caso = Training cortical signals by means of a BMI-EEG system, its evolution and intervention. A case report

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    INTRODUCTION: In the last years, new technologies such as the brain-machine interfaces (BMI) have been incorporated in the rehabilitation process of subjects with stroke. These systems are able to detect motion intention, analyzing the cortical signals using different techniques such as the electroencephalography (EEG). This information could guide different interfaces such as robotic devices, electrical stimulation or virtual reality. CASE REPORT: A 40 years-old man with stroke with two months from the injury participated in this study. We used a BMI based on EEG. The subject's motion intention was analyzed calculating the event-related desynchronization. The upper limb motor function was evaluated with the Fugl-Meyer Assessment and the participant's satisfaction was evaluated using the QUEST 2.0. The intervention using a physical therapist as an interface was carried out without difficulty. CONCLUSIONS: The BMI systems detect cortical changes in a subacute stroke subject. These changes are coherent with the evolution observed using the Fugl-Meyer Assessment

    The influence of brazilian soils properties in Americium sorption.

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    Although some radioecological studies have been accomplished in Brazilian soils supplying useful information to optimization of emergency planning actions in rural areas and to the management of soils contaminated by 137Cs, 60Co and 90Sr, few studies were made with transuranic elements in tropical agricultural areas. The different scenarios found in Brazilian agricultural environments enhance the importance of studying the biogeochemical behavior of radionuclides in representative soils. The objective of this work was to determine the mobility of 241Am in 3 different Brazilian agricultural soils evaluating migration with depth and Kd values for 241Am and the effect of organic amendments on this behavior. A strong effect of organic amendments on mobility of americium could be observed. The values of Kd obtained in all studied tropical soils were however smaller than those found in European soils and from those recommended by IAEA to be used as default values in the absence of regional data. This result reinforces the vulnerability of some tropical soils to a contamination, emphasizing the need to use of regional values

    A spin foam model for general Lorentzian 4-geometries

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    We derive simplicity constraints for the quantization of general Lorentzian 4-geometries. Our method is based on the correspondence between coherent states and classical bivectors and the minimization of associated uncertainties. For spacelike geometries, this scheme agrees with the master constraint method of the model by Engle, Pereira, Rovelli and Livine (EPRL). When it is applied to general Lorentzian geometries, we obtain new constraints that include the EPRL constraints as a special case. They imply a discrete area spectrum for both spacelike and timelike surfaces. We use these constraints to define a spin foam model for general Lorentzian 4-geometries.Comment: 27 pages, 1 figure; v4: published versio

    Correlation of diaphragm surgical findings with preoperative CT scans in ovarian cancer

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    Correlation of diaphragm surgical findings in ovarian cancer patients with and without diaphragm metastases with pre-operative CT diaphragm findings to assess sensitivity and specificity for diaphragm disease. Material and Methods: A retrospective study of 120 ovarian cancer patients (60 with and 60 without diaphragm metastases at surgery), FIGO Stage IIIC or IV, undergoing cytoreductive surgery at Mayo Clinic, Arizona, between January 2000 and October 2014. All patients had preoperative imaging with CT scan of abdomen and pelvis including the lower lung fields. CTs were not reviewed retrospectively. Results: Among 60 patients with diaphragm metastases, preoperative CTs were positive for diaphragm disease in 17 patients, with a sensitivity rate of 28% (CI 95%: 0.17-0.41). All 60 patients with no diaphragm metastases had negative CTs, with a specificity of 100% (CI 95%: 94.0%-100%). When analyzed by lesion size, CTs were negative in 66.7-80% of patients with diaphragm lesions ranging from 1-15 mm. There was a trend towards increased detection rate with increasing size of lesions, but it did not reach significance (p = 0.529). CT detection rate for single metastatic lesion was 18.2% (6/33) and for multiple lesions it was 25.9% (7/27). There was no difference for CT identification of right, left, or bilateral metastases (p = 0.399). The sensitivity and specificity of CT for pleural effusion was 100% (CI 95%: 72.2%-100%) and 88% (CI 95%: 76.2%- 94.4%), respectively. The area under the receiver operating characteristic (ROC) curve was 0.680 (CI 95%: 55.3%-72.2%) for CT detection of diaphragm metastases and 0.957 (CI 95%: 79.9%-95.3%) for pleural effusions. Conclusion: CT has a low sensitivity and a high specificity for the prediction of diaphragm metastases in ovarian cancer. The size, location, and number of diaphragm lesions do not significantly improve CT detection rat
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