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J Nogués

Publications and source records attributed to J Nogués.

13 recordsLinked to original sources
PubMed2006

Shell-driven magnetic stability in core-shell nanoparticles.

The magnetic properties of ferromagnetic-antiferromagnetic Co-CoO core-shell nanoparticles are investigated as a function of the in-plane coverage density from 3.5% to 15%. The superparamagnetic blocking temperature, the coercivity, and the bias field radically increase with increasing coverage. This behavior cannot be attributed to the overall interactions between cores. Rather, it can be semiquantitatively understood by assuming that the shells of isolated core-shell nanoparticles have strongly degraded magnetic properties, which are rapidly recovered as nanoparticles come into contact.

Cobalt↗
PubMed2006

Imprinting vortices into antiferromagnets.

The effect of imprinting symmetric and displaced vortex structures into an antiferromagnetic material is investigated in micron-sized disks consisting of exchange coupled ferromagnetic-antiferromagnetic bilayers. The imprint of displaced vortices manifests itself by the occurrence of a new type of asymmetric hysteresis loops characterized by curved, reversible, central sections with nonzero remanent magnetization. Such an imprint is achieved by cooling the disks through the blocking temperature of the system in small fields. Micromagnetic simulations reveal that asymmetric vortexlike loops naturally result from the competition between the different energies involved in the system.

Journal Article↗
PubMed2005

Magnetization reversal in submicron disks: exchange biased vortices.

Submicron, circular, ferromagnetic-antiferromagnetic dots exhibit different magnetization reversal mechanisms depending on the direction of the magnetic applied field. Shifted, constricted hysteresis loops, typical for vortex formation, are observed for fields along the exchange bias direction. However, for fields applied close to perpendicular to the exchange bias direction, magnetization reversal occurs via coherent rotation. Magnetic force microscopy imaging together with micromagnetic simulations are used to further clarify the different magnetic switching behaviors.

Journal Article↗
PubMed2001

Two-stage magnetization reversal in exchange biased bilayers.

MnF(2)/Fe bilayers exhibit asymmetric magnetization reversal that occurs by coherent rotation on one side of the loop and by nucleation and propagation of domain walls on the other side of the loop. Here, we show by polarized neutron reflectometry, magnetization, and magnetotransport measurements that for samples with good crystalline "quality" the rotation is a two-stage process, due to coherent rotation to a stable state perpendicular to the cooling field direction. The result is remarkably asymmetrically shaped hysteresis loops.

Journal Article↗
PubMed2001

[Neoplastic invasion of laryngeal cartilage: diagnosis by computed tomography].

The diagnostic of the laryngeal cartilage neoplastic invasion plays an important role in the accurate staging of the laryngeal carcinoma and its treatment. To evaluate the accuracy of the CT diagnosing cartilage involvement, the present study is reported. 127 patients with carcinoma of the larynx and hipopharynx T3-T4, surgical treated between 1993 and 1997 at Ciudad Sanitaria y Universitaria de Bellvitge, are retrospectively studied. TC presents an a accuracy of 78%, a specificity of 91% and a sensitivity of 54% in the diagnostic of laryngeal cartilage invasion of the laryngeal and hipopharyngeal carcinoma.

Aged↗
PubMed2001

[Crico-tracheal chondrosarcoma].

Chondrosarcoma is the most frequent mesenchymal tumor (nonepithelial) of the larynx. Radiographic studies and collaboration of pathologists have allowed that the number of cases diagnosed has increased considerably in the last few years. His privileged site is the subglotics. The late apparition of the symptoms delay the diagnosis, which is guided by CT scan and will be confirmed by histological examination of the surgical piece. The histological distinction between the different degrees of malignancy constitutes one challenge for the pathologist, so far, various criteria have been described for that aim. This biological behaviour is characterized by locoregional recurrence, in direct correlation with the grade of dedifferentiation. The treatment of choice is conservative surgical resection, and a regular follow up is obliged for early detection of recurrences and metastases. A case treated in our Center is presented, and the conclusions obtained after a literature review of the subject.

Chondrosarcoma↗
PubMed2000

Land Evaluation in a Salt-Affected Irrigated District Using an Index of Productive Potential.

/ The indiscriminate allocation of funds supporting agricultural policies can lead to land misuse, with undesirable effects either on the shorter to mid-term productivity or on the environment. This article proposes a methodology, based on land rating, that can be useful to land-use planning or to decide about environmental protection measures. The methodology is applied to the land evaluation of a 260-km(2) semiarid irrigated area with salt-affected soils. The available soil map is at 1:100,000 scale and its mapping units are used for the land evaluation with the FAO framework. These data are then elaborated using the index value method. This procedure gives a map of land evaluation units and a table that rates the productive potential of these units for six crops: alfalfa, barley, maize, rice, sunflower, and wheat.

Journal Article↗
PubMed2000

[Laryngeal leiomyoma].

A case of a 41-year-old man with a simple leiomyoma is reported. The pathological features of these tumors are described and also the therapeutic ones. A review of the literature confirmed that the laryngeal leiomyoma is a very infrequent neoplasm and only 36 cases have been reported previously.

Adult↗
PubMed1991

[Evaluation of the use of digoxin in a primary care emergency service].

Digoxin is a widely used drug. Previous studies suggest a high prevalence of inadequate use, subtherapeutic levels and high toxicity rates. The aim of the present study was to evaluation the use of digoxin in our area. 50 consecutive patients who attended our emergency service and who were receiving digoxin on a chronic basis were prospectively evaluated. There were 37 females and males, with age 78.1 +/- 8.6 years. We found that digoxin was not indicated in 12% of cases. Only 48% had digoxin plasma levels within the therapeutic range. When plasma levels were considered in association with clinical and electrocardiographic findings, 12% of patients were undertreated and 6% had digitalis toxicity. There was no relation between the digoxin plasma level and the dosage schedule, the ECG findings, the renal function, the use of other drugs or the anthropometric data. Emphasis is made on the need to individualize digoxin therapy and to measure plasma levels in particular cases.

Aged↗
PubMedDate not supplied

Bilateral facial nerve palsy: four case reports.

Bilateral facial nerve palsy is relatively uncommon and may occur in association with a variety of neurological, infectious, neoplastic or degenerative disorders. Presentation is made of 4 cases of bilateral facial diplegia due to a refractory anemia with excess of blasts, a Lyme disease and a tuberculoid leprosy. In one of these patients the cause of bilateral seventh-nerve palsy was unknown (Bell's palsy). Facial palsy returned to normal after treatment with steroids in 3 patients. The patient with myelodysplastic syndrome did not show any improvement and died 6 months after diagnosis.

Adult↗
PubMedDate not supplied

[Minor salivary gland tumor in nasopharynx].

Pleomorphic adenoma, or mixed tumor, is the most common tumor of the salivary glands, being responsible for 47% of minor salivary-gland neoplasms. The palate is the most frequent location, but the nasopharynx is a rare site. The case of a 64-year-old man diagnosed as pleomorphic adenoma of the nasopharynx is reported. The recent literature was reviewed and the anatomopathological and clinical features were analyzed, as well as the differential diagnosis.

Adenoma, Pleomorphic↗