Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 8 de 8
Filter
Add more filters










Publication year range
2.
Sci Rep ; 13(1): 14366, 2023 Sep 01.
Article in English | MEDLINE | ID: mdl-37658090

ABSTRACT

Superconducting microwave resonators are crucial elements of microwave circuits, offering a wide range of potential applications in modern science and technology. While conventional low-T[Formula: see text] superconductors are mainly employed, high-T[Formula: see text] cuprates could offer enhanced temperature and magnetic field operating ranges. Here, we report the realization of [Formula: see text] superconducting coplanar waveguide resonators, and demonstrate a continuous evolution from a lossy undercoupled regime, to a lossless overcoupled regime by adjusting the device geometry, in good agreement with circuit model theory. A high-quality factor resonator was then used to perform electron spin resonance measurements on a molecular spin ensemble across a temperature range spanning two decades. We observe spin-cavity hybridization indicating coherent coupling between the microwave field and the spins in a highly cooperative regime. The temperature dependence of the Rabi splitting and the spin relaxation time point toward an antiferromagnetic coupling of the spins below 2 K. Our findings indicate that high-Tc superconducting resonators hold great promise for the development of functional circuits. Additionally, they suggest novel approaches for achieving hybrid quantum systems based on high-T[Formula: see text] superconductors and for conducting electron spin resonance measurements over a wide range of magnetic fields and temperatures.

3.
Nat Commun ; 13(1): 4625, 2022 Aug 08.
Article in English | MEDLINE | ID: mdl-35941153

ABSTRACT

After almost twenty years of intense work on the celebrated LaAlO3/SrTiO3system, the recent discovery of a superconducting two-dimensional electron gas (2-DEG) in (111)-oriented KTaO3-based heterostructures injects new momentum to the field of oxides interface. However, while both interfaces share common properties, experiments also suggest important differences between the two systems. Here, we report gate tunable superconductivity in 2-DEGs generated at the surface of a (111)-oriented KTaO3 crystal by the simple sputtering of a thin Al layer. We extract the superfluid stiffness of the 2-DEGs and show that its temperature dependence is consistent with a node-less superconducting order parameter having a gap value larger than expected within a simple BCS weak-coupling limit model. The superconducting transition follows the Berezinskii-Kosterlitz-Thouless scenario, which was not reported on SrTiO3-based interfaces. Our finding offers innovative perspectives for fundamental science but also for device applications in a variety of fields such as spin-orbitronics and topological electronics.

4.
J Endocrinol Invest ; 44(1): 183-193, 2021 Jan.
Article in English | MEDLINE | ID: mdl-32441006

ABSTRACT

PURPOSE: To identify presurgical clinical, hormonal and radiological variables associated with surgical remission in acromegaly and develop a predictive model for surgical remission. METHODS: Ambispective study of acromegaly surgical patients followed in two Spanish tertiary hospitals. Patients operated by the same neurosurgeon by endonasal endoscopic transsphenoidal approach (n = 49) were included to develop the predictive model, and patients operated by other neurosurgeons (n = 37) were used for external validation of the predictive model. The predictive model was developed with a multivariate logistic regression model based on the 2000 criteria. RESULTS: 86 acromegalic patients were included. 49 patients, 83.7% with macroadenomas and 32.7% with Knosp grade > 2, were included for the development of the predictive model. The overall rate of surgical remission with the 2000 criteria was 73.5% and 51.0% with the 2010 criteria. Using the 2000 criteria, variables associated with surgical remission were: older age (OR = 1.1, p = 0.001), lower basal presurgical GH levels (OR = 0.9, p = 0.003), Knosp 0-2 (OR = 34.1, p < 0.0001) and lower maximum pituitary adenoma diameter (OR = 0.9, p = 0.019). The model with the best diagnostic accuracy to predict surgical remission combined age, Knosp 0-2 and presurgical GH levels (AIC = 29.7, AUC = 0.95) with a sensitivity of 93.8% and a specificity of 75.0%. The estimated loss of prediction with the external validation (n = 37) was 4.2%. CONCLUSION: The predictive model with the best diagnosis accuracy for surgical remission combined age, Knosp 0-2 and presurgical GH levels, with a sensitivity of 93.8% and a specificity of 75.0%. This model could be very useful to select candidates to preoperative medical treatment and planning the follow-up.


Subject(s)
Acromegaly/surgery , Endoscopy/methods , Human Growth Hormone/blood , Pituitary Neoplasms/surgery , Acromegaly/etiology , Female , Follow-Up Studies , Humans , Male , Middle Aged , Pituitary Neoplasms/complications , Predictive Value of Tests , Remission Induction , Retrospective Studies , Treatment Outcome
5.
Nat Mater ; 18(9): 948-954, 2019 Sep.
Article in English | MEDLINE | ID: mdl-31086324

ABSTRACT

In multi-orbital materials, superconductivity can exhibit several coupled condensates. In this context, quantum confinement in two-dimensional superconducting oxide interfaces offers new degrees of freedom to engineer the band structure and selectively control the occupancy of 3d orbitals by electrostatic doping. Here, we use resonant microwave transport to extract the superfluid stiffness of the (110)-oriented LaAlO3/SrTiO3 interface in the entire phase diagram. We provide evidence of a transition from single-condensate to two-condensate superconductivity driven by continuous and reversible electrostatic doping, which we relate to the Lifshitz transition between 3d bands based on numerical simulations of the quantum well. We find that the superconducting gap is suppressed while the second band is populated, challenging Bardeen-Cooper-Schrieffer theory. We ascribe this behaviour to the existence of superconducting order parameters with opposite signs in the two condensates due to repulsive coupling. Our findings offer an innovative perspective on the possibility to tune and control multiple-orbital physics in superconducting interfaces.

6.
Arch Esp Urol ; 65(1): 39-50, 2012.
Article in Spanish | MEDLINE | ID: mdl-22318176

ABSTRACT

In this narrative review we present the concept of nomogram in the context of predictive models in prostate cancer. In fact we try to answer the following questions from a practical and critical point of view: What is a nomogram? How to read and evaluate nomograms? What nomograms predict biochemical relapse in prostate cancer after local treatment, either surgery or radiotherapy? Why are nomograms better than risk groups stratification? And, finally, why don't clinicians use nomograms in fact?


Subject(s)
Neoplasm Recurrence, Local/blood , Nomograms , Prostate-Specific Antigen/blood , Prostatic Neoplasms/blood , Prostatic Neoplasms/epidemiology , Humans , Male , Prostatic Neoplasms/therapy
7.
Arch. esp. urol. (Ed. impr.) ; 65(1): 39-50, ene.-feb. 2012. tab, graf, ilus
Article in Spanish | IBECS | ID: ibc-101153

ABSTRACT

En la presente revisión narrativa presentamos una actualización del concepto de nomograma en el contexto de los modelos predictivos en cáncer de próstata. En realidad pretendemos dar respuesta desde un punto de vista práctico y a la vez crítico a las siguientes preguntas: ¿Qué es un nomograma?, ¿Cómo se leen y evalúan los nomogramas?, ¿Qué nomogramas predicen la recidiva bioquímica en cáncer de próstata tras tratamiento local, cirugía o radioterapia?, ¿Por qué son mejores los nomogramas que la estratificación en grupos de riesgo? y finalmente, ¿Por qué, en realidad, no se usan los nomogramas?(AU)


In this narrative review we present the concept of nomogram in the context of predictive mo-dels in prostate cancer. In fact we try to answer the following questions from a practical and critical point of view: What is a nomogram? How to read and evaluate nomograms? What nomograms predict biochemical relapse in prostate cancer after lo-cal treatment, either surgery or radiotherapy? Why are nomograms better than risk groups stratification? And, finally, Why don`t clinicians use nomograms in fact?(AU)


Subject(s)
Humans , Male , Forecasting/methods , Neoplasm Recurrence, Local/diagnosis , Recurrence , Prostatic Neoplasms/diagnosis , Nomograms
SELECTION OF CITATIONS
SEARCH DETAIL
...