Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 7 de 7
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
J Phys Condens Matter ; 36(5)2023 Oct 30.
Artigo em Inglês | MEDLINE | ID: mdl-37820641

RESUMO

We investigate the effects of non-magnetic disorder in a hybridized two-dimensional two-orbital s-wave superconductor (SC) model. The situation in which electronic orbitals overlap such that the hybridizationVi,jamong them is antisymmetric, under inversion symmetry, was taken into account. The on-site disorder is given by a random impurity potentialW. We find that while the random disorder acts to the detriment of superconductivity, hybridization proceeds to favor it. Accordingly, hybridization plays an important role in two-orbital models of superconductivity, in order to hold the long-range order against the increase of disorder. This makes the present model eligible to describe real materials, since the hybridization may be induced by pressure or doping. In addition, the regime from moderate to strong disorder reveals that the system is broken into SC islands with correlated local order parameters. These correlations persist to distances of several order lattice spacing which corresponds to the size of the SC-Islands.

2.
Sci Rep ; 11(1): 22524, 2021 Nov 18.
Artigo em Inglês | MEDLINE | ID: mdl-34795344

RESUMO

A proposal to study topological models beyond the standard topological classification and that exhibit breakdown of Lorentz invariance is presented. The focus of the investigation relies on their anisotropic quantum critical behavior. We study anisotropic effects on three-dimensional (3D) topological models, computing their anisotropic correlation length critical exponent [Formula: see text] obtained from numerical calculations of the penetration length of the zero-energy surface states as a function of the distance to the topological quantum critical point. A generalized Weyl semimetal model with broken time-reversal symmetry is introduced and studied using a modified Dirac equation. An approach to characterize topological surface states in topological insulators when applied to Fermi arcs allows to capture the anisotropic critical exponent [Formula: see text]. We also consider the Hopf insulator model, for which the study of the topological surface states yields unusual values for [Formula: see text] and for the dynamic critical exponent z. From an analysis of the energy dispersions, we propose a scaling relation [Formula: see text] and [Formula: see text] for [Formula: see text] and z that only depends on the Hopf insulator Hamiltonian parameters p and q and the axis direction [Formula: see text]. An anisotropic quantum hyperscaling relation is also obtained.

3.
J Phys Condens Matter ; 30(44): 445605, 2018 Nov 07.
Artigo em Inglês | MEDLINE | ID: mdl-30222128

RESUMO

In this work, we introduce the Heisenberg Ising-Kondo necklace with transverse field as a possible model to describe the heavy-fermion compound URu2Si2. The physics of this compound presents many open questions, like the transition to the hidden order (HO) phase at T 0 = 17.5 K. Our Hamiltonian includes elements that come from crystal field processes and Ruderman-Kittel-Kasuya-Yosida (RKKY) interaction. The main idea is to allow the transverse field, that a priori acts only in the localized moments, to influence the conduction-electrons via the RKKY interaction. Our results, obtained using a spin-wave approach for a one-dimensional lattice system, reveal a re-entrance behavior on the zero temperature phase diagram. This is an interesting result since combined with the magnetization values of the canted AF phase allow to link this phase with the mixed hidden order/large moment antiferromagnetic (HO/LMAF) phase observed in URu2Si2.

4.
Clin Nucl Med ; 27(6): 419-26, 2002 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-12045434

RESUMO

PURPOSE: To describe the radionuclide three-phase whole-body bone imaging (TPWBBI) technique and discuss the usefulness of its application. MATERIALS AND METHODS: TPWBBI was performed after a single intravenous injection of 555 to 925 MBq (15 to 25 mCi) Tc-99m MDP. Whole-body arterial flow (phase one) followed by blood-pool and tissue perfusion (phase two) images were obtained with the moving detector head speed set at 150 cm/minute and 40 cm/minute, respectively. Conventional whole-body static bone images (phase three) were obtained 3 hours later. RESULTS: When 542 consecutive TPWBBI results were reviewed, 394 (166 extraskeletal and 228 skeletal) abnormalities were detected during phases one and two. The 166 extraosseous lesions included vascular diseases: abdominal aortic aneurysms and peripheral vascular diseases and renal abnormalities, liver abnormalities, ascites, and pleural effusions. Many of these were incidentally detected clinically significant findings and would not have been identified on conventional static bone images. It helps to differentiate among acute and chronic fractures, active and inactive inflammatory diseases such as arthritis or osteomyelitis, and Paget's disease. CONCLUSIONS: With a single injection of Tc-99m MDP, whole-body images obtained in the arterial phase, the blood-pool and tissue perfusion phase, and the static bone phase can identify many clinically significant skeletal and soft tissue abnormalities. TPWBBI can differentiate between active and inactive phases of different disease processes and thereby provide a diagnosis that is more specific than a conventional single-phase bone scan. It may be applicable as a tool for nuclear physical examination.


Assuntos
Doenças Ósseas/diagnóstico por imagem , Doenças do Sistema Digestório/diagnóstico por imagem , Doenças Urogenitais Femininas/diagnóstico por imagem , Doenças Urogenitais Masculinas , Cintilografia/métodos , Doenças Vasculares/diagnóstico por imagem , Contagem Corporal Total/métodos , Adulto , Idoso , Idoso de 80 Anos ou mais , Diagnóstico Diferencial , Estudos de Viabilidade , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Valor Preditivo dos Testes , Compostos Radiofarmacêuticos , Sensibilidade e Especificidade , Neoplasias de Tecidos Moles/diagnóstico por imagem , Medronato de Tecnécio Tc 99m
5.
Obstet Gynecol ; 80(1): 37-40, 1992 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-1603494

RESUMO

Fifty normally menstruating women staged laparoscopically as having minimal endometriosis were given an option to be treated with intrauterine insemination with or without ovarian stimulation. Twenty-five patients had unmedicated natural cycles (ie, no medication for follicular stimulation), and 25 underwent controlled ovarian hyperstimulation. All subjects received hCG to time ovulation, followed 36 hours later with intrauterine insemination. Sixteen pregnancies, eight in each group, resulted from a total of 132 cycles. The cumulative probabilities of conception for the first, second, and third cycles were 0.13, 0.26, and 0.38 in the natural-cycles group and 0.12, 0.25, and 0.34 in the medicated-cycles group, respectively (P greater than .05). Monthly fecundity was 0.14 for the natural-cycles group and 0.13 for the medicated-cycles group (P greater than .05). We conclude that there is no difference in pregnancy rates or monthly fecundity over a 3-month period with controlled ovarian hyperstimulation as opposed to natural cycles combined with intrauterine insemination.


Assuntos
Inseminação Artificial , Indução da Ovulação , Gravidez/estatística & dados numéricos , Endometriose/complicações , Feminino , Humanos , Infertilidade Feminina/etiologia , Estudos Retrospectivos , Neoplasias Uterinas/complicações
6.
Fertil Steril ; 49(5): 913-6, 1988 May.
Artigo em Inglês | MEDLINE | ID: mdl-3129319

RESUMO

Twelve patients receiving Buserelin and seven patients receiving danazol for treatment of endometriosis were studied to assess the effect of medication on plasma lipoproteins. Danazol significantly lowered plasma HDL-C levels at 6 months of treatment. Total plasma cholesterol was elevated at 6 months of therapy in the Buserelin group. No effect by either drug on plasma triglycerides was seen.


Assuntos
Busserrelina/uso terapêutico , Danazol/uso terapêutico , Endometriose/tratamento farmacológico , Lipoproteínas/sangue , Pregnadienos/uso terapêutico , Adulto , Colesterol/sangue , HDL-Colesterol/sangue , LDL-Colesterol/sangue , Endometriose/sangue , Feminino , Humanos
7.
Enzyme ; 32(1): 26-36, 1984.
Artigo em Inglês | MEDLINE | ID: mdl-6434302

RESUMO

Differential digitonin extraction of rat liver mitochondria and of mitochondria of livers of affected and unaffected male sparse fur mice released a lysine transcarbamylase activity from the mitochondria at a digitonin to protein ratio in between that for myokinase and glutamate dehydrogenase, but at a slightly lower ratio than the ornithine transcarbamylase activity. Homocitrulline formation by isolated rat liver mitochondria is independent of the uptake of lysine by mitochondria as evidenced by the insensitivity of homocitrulline formation to changes in the matrix pH, in contrast to citrulline formation from ornithine. High-performance liquid chromatography separates the lysine transcarbamylase activity from the ornithine transcarbamylase activity. It is concluded that the lysine transcarbamylase activity is localized outside the inner mitochondrial membrane.


Assuntos
Citrulina/análogos & derivados , Camundongos Mutantes/fisiologia , Ornitina Carbamoiltransferase/metabolismo , Animais , Citrulina/biossíntese , Citrulina/urina , Feminino , Concentração de Íons de Hidrogênio , Cinética , Lisina/metabolismo , Masculino , Camundongos , Mitocôndrias Hepáticas/enzimologia , Ornitina/metabolismo , Ratos
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...