Twisted bilayer graphene (TBG) represents a highly tunable, strongly correlated electron system. However, understanding the single-particle band structure alone has been challenging due to a lack of spectroscopic measurements over a broad energy range. Here, we probe the band structure of TBG around the magic angle using infrared spectroscopy and reveal spectral features that originate from interband transitions.
View Article and Find Full Text PDFExtensive efforts have been undertaken to combine superconductivity and the quantum Hall effect so that Cooper-pair transport between superconducting electrodes in Josephson junctions is mediated by one-dimensional edge states. This interest has been motivated by prospects of finding new physics, including topologically protected quasiparticles, but also extends into metrology and device applications. So far it has proven challenging to achieve detectable supercurrents through quantum Hall conductors.
View Article and Find Full Text PDFThe most recognizable feature of graphene's electronic spectrum is its Dirac point, around which interesting phenomena tend to cluster. At low temperatures, the intrinsic behaviour in this regime is often obscured by charge inhomogeneity but thermal excitations can overcome the disorder at elevated temperatures and create an electron-hole plasma of Dirac fermions. The Dirac plasma has been found to exhibit unusual properties, including quantum-critical scattering and hydrodynamic flow.
View Article and Find Full Text PDFBackground: The generation of antigen-specific memory B cells is crucial to the long-term effectiveness of vaccines. When the protective antibodies circulating in the blood wane, memory B cells (MBC) can be rapidly reactivated and differentiated into antibody-secreting cells during a new infection. Such MBC responses are considered to be key in providing long-term protection after infection or vaccination.
View Article and Find Full Text PDFIn quantizing magnetic fields, graphene superlattices exhibit a complex fractal spectrum often referred to as the Hofstadter butterfly. It can be viewed as a collection of Landau levels that arise from quantization of Brown-Zak minibands recurring at rational (p/q) fractions of the magnetic flux quantum per superlattice unit cell. Here we show that, in graphene-on-boron-nitride superlattices, Brown-Zak fermions can exhibit mobilities above 10 cm V s and the mean free path exceeding several micrometers.
View Article and Find Full Text PDFOf the two stable forms of graphite, hexagonal and rhombohedral, the former is more common and has been studied extensively. The latter is less stable, which has so far precluded its detailed investigation, despite many theoretical predictions about the abundance of exotic interaction-induced physics. Advances in van der Waals heterostructure technology have now allowed us to make high-quality rhombohedral graphite films up to 50 graphene layers thick and study their transport properties.
View Article and Find Full Text PDFObjective: Studies have shown that aortitis may be present in half the patients with recent-onset giant cell arteritis (GCA). We assessed whether aortitis at diagnosis affects longterm outcome in patients with GCA.
Methods: We retrospectively analyzed the longterm outcome of a prospective cohort of 22 patients with biopsy-proven GCA who all had aortic computed tomography (CT) evaluation at the time of diagnosis of GCA between May 1998 and November 1999.
Objectives: A key element of medical competence is problem solving. Previous work has shown that doctors use inductive reasoning to progress from facts to hypotheses and deductive reasoning to move from hypotheses to the gathering of confirmatory information. No individual assessment method has been designed to quantify the use of inductive and deductive procedures within clinical reasoning.
View Article and Find Full Text PDFObjective: This study used Doppler ultrasonography and computed tomographic angiography (CTA) to assess the prevalence of abdominal aortic lesions that suggested abdominal aortitis at diagnosis of giant-cell or temporal arteritis (GCA). We also evaluated the contribution of these 2 techniques to diagnosis.
Methods: This single-center study included patients admitted to the internal medicine department of the Nantes (France) University Hospital, between May 1999 and May 2002 at the time of their diagnosis with biopsy-proven GCA.
Objective: The prevalence of the involvement of large vessels in giant cell arteritis (GCA) is 3-13%. Aortitis is the most serious complication of GCA. Computed tomodensitometric (CT) scan allows analysis of both the aortic wall and endoluminal part of the aorta.
View Article and Find Full Text PDFJ Gynecol Obstet Biol Reprod (Paris)
December 2007
Objectives: The evaluation of an educational system is part of the essential process to get high-quality teaching. We wanted to assess the teaching and the teachers in a gynaecological unit with a view to improve the education of the trainees within a dynamic educational system.
Materials And Methods: It is a prospective study which took place in the gynecology-obstetric unit of the University of Nantes.
Background: Churg-Strauss syndrome (CSS) is a necrotizing systemic vasculitis with extravascular granulomas and eosinophilic infiltrates of small vessels. CSS is usually revealed by nonspecific signs of necrotizing vasculitis in a context of late-onset asthma and blood eosinophilia. It is considered a systemic vasculitis with the highest prevalence of cardiac involvement and can lead to rapid-onset heart failure due to specific cardiomyopathy.
View Article and Find Full Text PDFBackground: Inflammatory involvement of extracranial large-sized arteries occurs in 10-20% of patients with giant cell (temporal) arteritis. Aortic involvement may reveal giant cell arteritis or occur as a late-onset complication, and represents one of the most serious manifestation of the disease with the risk of aortic dissection and/or aneurysm rupture. The thoracic aorta is more frequently involved but abdominal aortitis may also occur in giant cell arteritis.
View Article and Find Full Text PDFPurpose: Few data are available on the prevalence and causes of hyponatremia in medical setting and to our knowledge, no recent descriptive study has been performed about hyponatremias in the French Departments of internal medicine.
Method: A "one day" descriptive multicentric study was performed in the medicine departments of the France West area. A questionnaire was mailed to physicians who had to take part in a annual regional meeting about "hyponatremias", one month later.
J Gynecol Obstet Biol Reprod (Paris)
June 2006
We report the cases of two patients who had a favorable outcome with aspirin and corticosteroid therapy during pregnancy for chronic villitis of unknown etiology complicated by labor asphyxia and further intrauterine fetal demise in one gravida 3 patient and for chronic intervillositis of unknown etiology diagnosed after three perinatal deaths in another patient (gravida 4). Chronic villitis of unknown etiology (CVUE) is detected in 7 to 33% of placentas, mainly after intrauterine growth retardation (IUGR), unexplained prematurity, preeclampsia, perinatal asphyxia and intrauterine fetal death (IUFD). The less frequent chronic intervillositis of unknown etiology (CIUE) (0.
View Article and Find Full Text PDFJ Cardiopulm Rehabil
December 2006
Purpose: The purposes of this investigation were to determine (1) if the 6-minute cycle (6MC) test is a valid and reliable measure of physical performance in cardiac patients and (2) if physiologic responses to the 6-minute walk (6MW) and 6MC tests differ in men and women.
Methods: Subjects were 101 phase II cardiac rehabilitation patients aged 40 to 79 years. Each subject performed a maximal graded exercise test (MGXT), a 6MW test, and three 6MC tests on separate days.
Objective: To provide information on morbidity and ethical questions associated with learning of invasive techniques (tracheal intubation, positioning of central venous or epidural catheters) and management of anaphylactic shock.
Study Design: Retrospective survey.
Methods: Written questionnaire to 54 anaesthesiologists and 55 residents.
Aortitis is the most serious location of the disease giant cell (temporal) arteritis (GCA). Aortic dissection or the rupture of an aortic aneurysm can be responsible for sudden death among patients with GCA. This report discusses two cases of GCA presenting with aortic dissection.
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