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1.
BJOG ; 128(12): 1975-1985, 2021 11.
Artículo en Inglés | MEDLINE | ID: mdl-34032350

RESUMEN

OBJECTIVE: To develop twin-specific outcome-based oral glucose tolerance test (OGTT) diagnostic thresholds for GDM based on the risk of future maternal type-2 diabetes. DESIGN: A population-based retrospective cohort study (2007-2017). SETTING: Ontario, Canada. METHODS: Nulliparous women with a live singleton (n = 55 361) or twin (n = 1308) birth who underwent testing for gestational diabetes mellitus (GDM) using a 75-g OGTT in Ontario, Canada (2007-2017). We identified the 75-g OGTT thresholds in twin pregnancies that were associated with similar incidence rates of future type-2 diabetes to those associated with the standard OGTT thresholds in singleton pregnancies. RESULTS: For any given 75-g OGTT value, the incidence rate of future maternal type-2 diabetes was lower for women with a twin than women with a singleton pregnancy. Using women with a negative OGTT as reference, the risk of future maternal type-2 diabetes in twin pregnancies with a positive OGTT based on the standard OGTT thresholds (9.86 per 1000 person years, adjusted hazard ratio (aHR) 4.79, 95% CI 2.69-8.51) was lower than for singleton pregnancies with a positive OGTT (18.74 per 1000 person years, aHR 8.22, 95% CI 7.38-9.16). The twin-specific OGTT fasting, 1-hour and 2-hour thresholds identified in the current study based on correlation with future maternal type-2 diabetes were 5.8 mmol/l (104 mg/dl), 11.8 mmol/l (213 mg/dl) and 10.4 mmol/l (187 mg/dl), respectively. CONCLUSIONS: We identified potential twin-specific OGTT thresholds for GDM that are associated with a similar risk of future type-2 diabetes to that observed in women diagnosed with GDM in singleton pregnancies based on standard OGTT thresholds. TWEETABLE ABSTRACT: Potential twin-specific OGTT thresholds for GDM were identified.


Asunto(s)
Diabetes Mellitus Tipo 2/etiología , Diabetes Gestacional/diagnóstico , Prueba de Tolerancia a la Glucosa/estadística & datos numéricos , Embarazo Gemelar/sangre , Medición de Riesgo/estadística & datos numéricos , Adulto , Glucemia/análisis , Diabetes Mellitus Tipo 2/epidemiología , Ayuno/sangre , Femenino , Humanos , Incidencia , Ontario/epidemiología , Embarazo , Valores de Referencia , Estudios Retrospectivos , Factores de Riesgo
2.
Phys Rev Lett ; 125(7): 076401, 2020 Aug 14.
Artículo en Inglés | MEDLINE | ID: mdl-32857568

RESUMEN

In nodal-line semimetals, linearly dispersing states form Dirac loops in the reciprocal space with a high degree of electron-hole symmetry and a reduced density of states near the Fermi level. The result is reduced electronic screening and enhanced correlations between Dirac quasiparticles. Here we investigate the electronic structure of ZrSiSe, by combining time- and angle-resolved photoelectron spectroscopy with ab initio density functional theory (DFT) complemented by an extended Hubbard model (DFT+U+V) and by time-dependent DFT+U+V. We show that electronic correlations are reduced on an ultrashort timescale by optical excitation of high-energy electrons-hole pairs, which transiently screen the Coulomb interaction. Our findings demonstrate an all-optical method for engineering the band structure of a quantum material.

3.
BJOG ; 127(9): 1154-1164, 2020 08.
Artículo en Inglés | MEDLINE | ID: mdl-32175668

RESUMEN

OBJECTIVE: Data regarding low maternal haemoglobin concentration and severe maternal morbidity (SMM) are limited and potentially biased. This study evaluated the relation between early maternal haemoglobin concentration and SMM or maternal mortality. DESIGN: Population-based cohort study. SETTING: Ontario, Canada, in a public healthcare system. POPULATION: 737 393 births with a routine outpatient haemoglobin measured at a calculated gestational age of 2-16 weeks. METHODS: The relation between early-pregnancy outpatient blood haemoglobin concentration and each study outcome was expressed as adjusted relative risks (aRR) and absolute risk differences (aRD), with 95% confidence intervals (CI), generated by modified Poisson regression. MAIN OUTCOME MEASURES: The primary outcome was SMM or maternal mortality, from 23 weeks' gestation to 42 days postpartum. RESULTS: The mean (SD) haemoglobin concentration was 126.9 (9.3) g/l. Overall, SMM or death occurred in 13 514 pregnancies (1.8%). Relative to a haemoglobin level of 125-129 g/l, the aRR was 1.07 (95% CI 1.02-1.13) and aRD (0.09%, 95% CI 0.01-0.18) at 120-124 g/l; aRR 1.31 (95% CI 1.17-1.46) and aRD 0.47% (95% CI 0.24-0.69) at 105-109 g/l; and aRR 4.53 (95% CI 3.59-5.72) and aRD 5.94% (95% CI 4.12-7.76) at <90 g/l. In all, 5961 women (0.8%) required red cell transfusion, with significantly higher risks at all haemoglobin concentrations below 125-129 g/l, peaking at a haemoglobin level <90 g/l (aRR 11.82, 95% CI 9.30-15.03). CONCLUSION: There is a gradual increase in the risk of SMM or death, as well as red cell transfusion, starting from the lower level of the normal range of haemoglobin of non-pregnant women. TWEETABLE ABSTRACT: Women with low haemoglobin in early pregnancy are at higher future risk of morbidity, death and blood transfusion.


Asunto(s)
Anemia/sangre , Anemia/epidemiología , Transfusión de Eritrocitos/estadística & datos numéricos , Hemoglobinas/metabolismo , Complicaciones del Embarazo/sangre , Complicaciones del Embarazo/epidemiología , Adulto , Anemia/mortalidad , Anemia/terapia , Femenino , Humanos , Mortalidad Materna , Ontario/epidemiología , Embarazo , Complicaciones del Embarazo/mortalidad , Complicaciones del Embarazo/terapia , Primer Trimestre del Embarazo/sangre , Estudios Retrospectivos , Factores de Riesgo
4.
Phys Rev Lett ; 122(21): 217402, 2019 May 31.
Artículo en Inglés | MEDLINE | ID: mdl-31283333

RESUMEN

Zirconium pentatelluride was recently reported to be a 3D Dirac semimetal, with a single conical band, located at the center of the Brillouin zone. The cone's lack of protection by the lattice symmetry immediately sparked vast discussions about the size and topological or trivial nature of a possible gap opening. Here, we report on a combined optical and transport study of ZrTe_{5}, which reveals an alternative view of electronic bands in this material. We conclude that the dispersion is approximately linear only in the a-c plane, while remaining relatively flat and parabolic in the third direction (along the b axis). Therefore, the electronic states in ZrTe_{5} cannot be described using the model of 3D Dirac massless electrons, even when staying at energies well above the band gap 2Δ=6 meV found in our experiments at low temperatures.

5.
Phys Rev Lett ; 121(13): 136401, 2018 Sep 28.
Artículo en Inglés | MEDLINE | ID: mdl-30312078

RESUMEN

Using soft x-ray angle-resolved photoemission spectroscopy we probed the bulk electronic structure of T_{d}-MoTe_{2}. We found that on-site Coulomb interaction leads to a Lifshitz transition, which is essential for a precise description of the electronic structure. A hybrid Weyl semimetal state with a pair of energy bands touching at both type-I and type-II Weyl nodes is indicated by comparing the experimental data with theoretical calculations. Unveiling the importance of Coulomb interaction opens up a new route to comprehend the unique properties of MoTe_{2}, and is significant for understanding the interplay between correlation effects, strong spin-orbit coupling and superconductivity in this van der Waals material.

6.
Rev Sci Instrum ; 89(4): 046101, 2018 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-29716319

RESUMEN

We present a compact nuclear magnetic resonance (NMR) probe which is compatible with a magnet of a commercial superconducting quantum interference device magnetometer and demonstrate its application to the study of a quantum magnet. We employ trimmer chip capacitors to construct an NMR tank circuit for low temperature measurements. Using a magnetic insulator MoOPO4 with S = 1/2 (Mo5+) as an example, we show that the T-dependence of the circuit is weak enough to allow the ligand-ion NMR study of magnetic systems. Our 31P NMR results are compatible with previous bulk susceptibility and neutron scattering experiments and furthermore reveal unconventional spin dynamics.

7.
Nat Commun ; 9(1): 2115, 2018 05 29.
Artículo en Inglés | MEDLINE | ID: mdl-29844391

RESUMEN

Magnetic skyrmions are particle-like, topologically protected magnetisation entities that are promising candidates as information carriers in racetrack memory. The transport of skyrmions in a shift-register-like fashion is crucial for their embodiment in practical devices. Here, we demonstrate that chiral skyrmions in Cu2OSeO3 can be effectively manipulated under the influence of a magnetic field gradient. In a radial field gradient, skyrmions were found to rotate collectively, following a given velocity-radius relationship. As a result of this relationship, and in competition with the elastic properties of the skyrmion lattice, the rotating ensemble disintegrates into a shell-like structure of discrete circular racetracks. Upon reversing the field direction, the rotation sense reverses. Field gradients therefore offer an effective handle for the fine control of skyrmion motion, which is inherently driven by magnon currents. In this scheme, no local electric currents are needed, thus presenting a different approach to shift-register-type operations based on spin transfer torque.

8.
Nano Lett ; 18(4): 2623-2629, 2018 04 11.
Artículo en Inglés | MEDLINE | ID: mdl-29529377

RESUMEN

It is well-known that superconductivity in thin films is generally suppressed with decreasing thickness. This suppression is normally governed by either disorder-induced localization of Cooper pairs, weakening of Coulomb screening, or generation and unbinding of vortex-antivortex pairs as described by the Berezinskii-Kosterlitz-Thouless (BKT) theory. Defying general expectations, few-layer NbSe2, an archetypal example of ultrathin superconductors, has been found to remain superconducting down to monolayer thickness. Here, we report measurements of both the superconducting energy gap Δ and critical temperature TC in high-quality monocrystals of few-layer NbSe2, using planar-junction tunneling spectroscopy and lateral transport. We observe a fully developed gap that rapidly reduces for devices with the number of layers N ≤ 5, as does their TC. We show that the observed reduction cannot be explained by disorder, and the BKT mechanism is also excluded by measuring its transition temperature that for all N remains very close to TC. We attribute the observed behavior to changes in the electronic band structure predicted for mono- and bi- layer NbSe2 combined with inevitable suppression of the Cooper pair density at the superconductor-vacuum interface. Our experimental results for N > 2 are in good agreement with the dependences of Δ and TC expected in the latter case while the effect of band-structure reconstruction is evidenced by a stronger suppression of Δ and the disappearance of its anisotropy for N = 2. The spatial scale involved in the surface suppression of the density of states is only a few angstroms but cannot be ignored for atomically thin superconductors.

9.
Gesundheitswesen ; 80(3): 232-239, 2018 Mar.
Artículo en Alemán | MEDLINE | ID: mdl-27272057

RESUMEN

BACKGROUND: There has been a steady increase in psychiatric primary diagnoses in medical rehabilitation services carried out by the statutory pension insurance (DRV). To date, no data are available regarding frequency, quality, and approval rates of applications for psychosomatic rehabilitation. Pension insurance physicians reviewing the application require sufficient information on rehabilitation-related needs, motivation, abilities, and prognosis of an insured person. Medical reports accompanying application for rehabilitation are often provided by a family physician. Psychiatric disorders are often misdiagnosed by general practitioners. METHOD: In a 2-week period, all decisions made by pension insurance physicians evaluating applications for rehabilitation were recorded. For each incoming application, the following data were documented: psychiatric and somatic primary diagnosis; availability of medical reports; information on prior treatment/therapy; request for further information; decision made by the physician. RESULTS: 1,366 applications (with 81% first-time applications) were included in the analysis. 16.2% of all applications were from insurants with psychiatric primary diagnoses. 44.0% of these applications included a medical report from the family physician only. The proportion of rejected applications (34.7%) and undecided applications (27.2%) was higher in the group of applicants with psychiatric primary diagnosis vs. somatic primary diagnosis (19.6% rejected; 12.7% undecided; χ2=79.8(4), p=0.001). Applications from patients with psychiatric primary diagnosis that lacked a medical report from a psychiatrist/psychotherapist were more likely to be rejected (45.3 vs. 32.3%) or to remain undecided (28.0 vs. 18.3%; χ2=10.2(2), p=0.006). In contrast, among applicants with a history of psychiatric/psychotherapeutic treatment, there was a higher proportion of undecided applications accompanied by a medical report from the family physician (35.7 vs. 18.2%). CONCLUSION: It might be useful to have medical reports generally provided by medical specialists. This may help both to increase the informative value of applications for psychosomatic rehabilitation and enable quicker decisions and better diagnosis.


Asunto(s)
Trastornos Mentales , Trastornos Psicofisiológicos , Alemania , Humanos , Pacientes Internos , Trastornos Mentales/rehabilitación , Pensiones , Trastornos Psicofisiológicos/rehabilitación
10.
Pharmacogenomics J ; 18(3): 391-397, 2018 05 22.
Artículo en Inglés | MEDLINE | ID: mdl-28696420

RESUMEN

Mothers with a CYP2D6 ultrarapid metabolizer phenotype may expose their infants to risk of adverse events when taking codeine while breastfeeding, by producing more of the active metabolite, morphine. Pharmacogenetic testing may be a valuable tool to identify such mothers, but testing can be costly. The objective of the study was to determine the incremental costs of genotyping to avert neonatal adverse events during maternal pharmacotherapy. A cost-effectiveness analysis, using a decision model, was performed with a hypothetical cohort of prenatal subjects. Parameter estimates, costs and ranges for sensitivity analyses were ascertained from the literature and expert opinion. Sensitivity analyses were conducted to assess the robustness of the results. Probabilistic sensitivity analysis revealed an incremental cost-effectiveness (ICER) of $10 433 (Canadian dollars) for genotyping compared to no genotyping per adverse event averted. Results were sensitive to hospital admission costs. The ICER was lower when evaluating only subjects having caesarean deliveries or those from ethnic populations known to have a high prevalence of ultra-rapid metabolizers. Although genotyping to guide pharmacotherapy was not cost saving, the cost to avert an infant adverse event may represent good value for money in specific populations. With a growing demand for personalized medicine, these findings are relevant for decision makers, clinicians and patients.


Asunto(s)
Citocromo P-450 CYP2D6/genética , Efectos Colaterales y Reacciones Adversas Relacionados con Medicamentos/genética , Dolor/tratamiento farmacológico , Periodo Posparto/genética , Lactancia Materna/economía , Canadá , Codeína/efectos adversos , Análisis Costo-Beneficio , Efectos Colaterales y Reacciones Adversas Relacionados con Medicamentos/economía , Femenino , Pruebas Genéticas/economía , Técnicas de Genotipaje/economía , Humanos , Lactante , Morfina , Dolor/economía , Dolor/genética , Dolor/patología , Periodo Posparto/efectos de los fármacos , Embarazo
11.
Sci Rep ; 7(1): 7037, 2017 08 01.
Artículo en Inglés | MEDLINE | ID: mdl-28765550

RESUMEN

Linear dichroism - the polarization dependent absorption of electromagnetic waves- is routinely exploited in applications as diverse as structure determination of DNA or polarization filters in optical technologies. Here filamentary absorbers with a large length-to-width ratio are a prerequisite. For magnetization dynamics in the few GHz frequency regime strictly linear dichroism was not observed for more than eight decades. Here, we show that the bulk chiral magnet Cu2OSeO3 exhibits linearly polarized magnetization dynamics at an unexpectedly small frequency of about 2 GHz at zero magnetic field. Unlike optical filters that are assembled from filamentary absorbers, the magnet is shown to provide linear polarization as a bulk material for an extremely wide range of length-to-width ratios. In addition, the polarization plane of a given mode can be switched by 90° via a small variation in width. Our findings shed a new light on magnetization dynamics in that ferrimagnetic ordering combined with antisymmetric exchange interaction offers strictly linear polarization and cross-polarized modes for a broad spectrum of sample shapes at zero field. The discovery allows for novel design rules and optimization of microwave-to-magnon transduction in emerging microwave technologies.

12.
Theriogenology ; 104: 115-119, 2017 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-28822902

RESUMEN

The objective was to compare luteal area (LA), luteal blood flow (LBF), and progesterone (P4) concentration before and after artificial insemination (AI) in pregnant and open cows in the diestrus preceding insemination and during the first 21 d after insemination. A number of 119 multiparous German Holstein cows were examined using B-mode and color Doppler sonography in diestrus (15-5 d before AI) and on days 7, 14, and 21 post insemination (pi). Blood samples for determination of P4 concentration were collected at each examination. In pregnant cows, P4 was measured in the diestrus before AI and on days 7, 14, and 21 of pregnancy, and in open cows, in the diestrus preceding the first AI and 7, 14, and 21 d later. Cows were retrospectively allocated into two groups according to the mean daily milk yield in the first 42 d (high milk yield [HMY], ≥39 kg/d; low milk yield [LMY], <39 kg/d). Pregnant cows had larger LA than open cows during diestrus before insemination (5.69 ± 1.85 vs. 4.94 ± 1.66 cm2, P < 0.05), on days 7 (5.34 ± 1.83 vs. 4.52 ± 1.93 cm2, P < 0.05) and 21 pi (5.92 ± 1.60 vs. 4.97 ± 1.44 cm2, P < 0.05). On day 14 there was a tendency towards larger LA in pregnant cows (P = 0.09). Luteal blood flow (1.72 ± 0.74 vs. 1.22 ± 0.67 cm2) and P4 concentration (8.97 ± 4.37 vs. 6.49 ± 4.32 ng/mL) were higher in pregnant cows than in open cows on day 21 (P < 0.05). At day 150, 69% of the LMY cows and 56% of the HMY cows were pregnant (P > 0.05). Pregnant HMY cows had larger LA during diestrus before insemination and on days 7 and 21 pi than open HMY cows (P < 0.05) and tended to result in larger CLs on day 14 (P = 0.06). Pregnant HMY cows had higher LBF on days 14 and 21 (P < 0.05) and higher P4 concentration on day 21 than open HMY cows (P < 0.05). The main finding of this study was a larger LA during diestrus in cows that conceived in the ensuing estrous cycle compared to cows that did not conceive. Luteal area, LBF, and P4 concentration were greater in pregnant cows compared to open cows, and further studies should be conducted on the usefulness of these variables to detect open cows as early as possible after breeding. High-yielding cows appear to require larger LA, LBF, and higher P4 concentration than low-yielding cows to maintain pregnancy. In conclusion, larger LAs were established in pregnant cows in the diestrus before successful insemination regardless of their milk yield. Further studies are needed to verify whether LA in the diestrus before insemination might be used to predict probabilities in reproductive performance.


Asunto(s)
Bovinos/fisiología , Cuerpo Lúteo/citología , Inseminación Artificial/veterinaria , Resultado del Embarazo , Preñez , Animales , Cuerpo Lúteo/fisiología , Diestro , Ciclo Estral/fisiología , Sincronización del Estro , Femenino , Lactancia , Leche , Ovulación , Embarazo , Preñez/fisiología , Progesterona/sangre
13.
Phys Rev Lett ; 118(20): 206401, 2017 May 19.
Artículo en Inglés | MEDLINE | ID: mdl-28581791

RESUMEN

High-resolution angle-resolved photoemission spectroscopy data reveal evidence of a crossover from one-dimensional (1D) to three-dimensional (3D) behavior in the prototypical charge density wave (CDW) material NbSe_{3}. In the low-temperature 3D regime, gaps in the electronic structure are observed due to two incommensurate CDWs, in agreement with x-ray diffraction and electronic-structure calculations. At higher temperatures we observe a spectral weight depletion that approaches the power-law behavior expected in one dimension. From the warping of the quasi-1D Fermi surface at low temperatures, we extract the energy scale of the dimensional crossover. This is corroborated by a detailed analysis of the density of states, which reveals a change in dimensional behavior dependent on binding energy. Our results offer an important insight into the dimensionality of excitations in quasi-1D materials.

14.
Phys Rev Lett ; 118(20): 207205, 2017 May 19.
Artículo en Inglés | MEDLINE | ID: mdl-28581772

RESUMEN

The chiral magnet Cu_{2}OSeO_{3} hosts a Skyrmion lattice that may be equivalently described as a superposition of plane waves or a lattice of particlelike topological objects. A thermal gradient may break up the Skyrmion lattice and induce rotating domains, raising the question of which of these scenarios better describes the violent dynamics at the domain boundaries. Here, we show that in an inhomogeneous temperature gradient caused by illumination in a Lorentz transmission electron microscope different parts of the Skyrmion lattice can be set into motion with different angular velocities. Tracking the time dependence, we show that the constant rearrangement of domain walls is governed by dynamic 5-7 defects arranging into lines. An analysis of the associated defect density is described by Frank's equation and agrees well with classical 2D Monte Carlo simulations. Fluctuations of boundaries show a surgelike rearrangement of Skyrmion clusters driven by defect rearrangement consistent with simulations treating Skyrmions as point particles. Our findings underline the particle character of the Skyrmion.

15.
Phys Rev Lett ; 118(17): 176404, 2017 Apr 28.
Artículo en Inglés | MEDLINE | ID: mdl-28498707

RESUMEN

We measured, by angle-resolved photoemission spectroscopy, the electronic structure of LiCu_{2}O_{2}, a mixed-valence cuprate where planes of Cu(I) (3d^{10}) ions are sandwiched between layers containing one-dimensional edge-sharing Cu(II) (3d^{9}) chains. We find that the Cu(I)- and Cu(II)-derived electronic states form separate electronic subsystems, in spite of being coupled by bridging O ions. The valence band, of the Cu(I) character, disperses within the charge-transfer gap of the strongly correlated Cu(II) states, displaying an unprecedented 250% broadening of the bandwidth with respect to the predictions of density functional theory. Our observation is at odds with the widely accepted tenet of many-body theory that correlation effects generally yield narrower bands and larger electron masses and suggests that present-day electronic structure techniques provide an intrinsically inappropriate description of ligand-to-d hybridizations in late transition metal oxides.

16.
J Phys Condens Matter ; 29(29): 295702, 2017 Jul 26.
Artículo en Inglés | MEDLINE | ID: mdl-28513467

RESUMEN

We report measurements of Shubnikov-de Haas oscillations in the giant Rashba semiconductor BiTeCl under applied pressures up to ∼2.5 GPa. We observe two distinct oscillation frequencies, corresponding to the Rashba-split inner and outer Fermi surfaces. BiTeCl has a conduction band bottom that is split into two sub-bands due to the strong Rashba coupling, resulting in two spin-polarized conduction bands as well as a Dirac point. Our results suggest that the chemical potential lies above this Dirac point, giving rise to two Fermi surfaces. We use a simple two-band model to understand the pressure dependence of our sample parameters. Comparing our results on BiTeCl to previous results on BiTeI, we observe similar trends in both the chemical potential and the Rashba splitting with pressure.

18.
Nat Commun ; 8(1): 13, 2017 04 13.
Artículo en Inglés | MEDLINE | ID: mdl-28408739

RESUMEN

Anatase TiO2 is among the most studied materials for light-energy conversion applications, but the nature of its fundamental charge excitations is still unknown. Yet it is crucial to establish whether light absorption creates uncorrelated electron-hole pairs or bound excitons and, in the latter case, to determine their character. Here, by combining steady-state angle-resolved photoemission spectroscopy and spectroscopic ellipsometry with state-of-the-art ab initio calculations, we demonstrate that the direct optical gap of single crystals is dominated by a strongly bound exciton rising over the continuum of indirect interband transitions. This exciton possesses an intermediate character between the Wannier-Mott and Frenkel regimes and displays a peculiar two-dimensional wavefunction in the three-dimensional lattice. The nature of the higher-energy excitations is also identified. The universal validity of our results is confirmed up to room temperature by observing the same elementary excitations in defect-rich samples (doped single crystals and nanoparticles) via ultrafast two-dimensional deep-ultraviolet spectroscopy.Here the authors combine steady-state angle-resolved photoemission spectroscopy, ellipsometry and ultrafast two-dimensional ultraviolet spectroscopy to examine the role of many-body correlations in anatase TiO2, revealing the existence of strongly bound excitons in single crystals and nanoparticles.

19.
Dig Liver Dis ; 49(7): 769-772, 2017 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-28314602

RESUMEN

BACKGROUND AND STUDY AIMS: Complete biliary strictures normally require surgical intervention. We describe an alternative, minimally invasive endoscopic/percutaneous rendez-vous technique for the reconstruction of complete benign biliary strictures. PATIENTS AND METHODS: Complete biliary strictures were reconstructed in four patients using a rendez-vous percutaneous-endoscopic or percutaneous-percutaneous route guided by fluoroscopic and visual (transillumination) control. RESULTS: All four patients were treated successfully and safely with the rendez-vous technique. Complications were caused by the preliminary creation, dilatation and maturation of the percutaneous tract. CONCLUSION: This technique may offer a good alternative to surgical bilio-enteric anastomosis in experienced hands. The long term course of the patients treated remains to be seen.


Asunto(s)
Conductos Biliares/cirugía , Colestasis/cirugía , Endoscopía del Sistema Digestivo , Adulto , Anciano , Anciano de 80 o más Años , Anastomosis Quirúrgica/efectos adversos , Colestasis/etiología , Dilatación/métodos , Femenino , Humanos , Masculino , Procedimientos Quirúrgicos Reconstructivos/métodos , Transiluminación/métodos
20.
J Phys Condens Matter ; 29(9): 09LT02, 2017 Mar 08.
Artículo en Inglés | MEDLINE | ID: mdl-28004645

RESUMEN

At ambient pressure, BiTeI exhibits a giant Rashba splitting of the bulk electronic bands. At low pressures, BiTeI undergoes a transition from trivial insulator to topological insulator. At still higher pressures, two structural transitions are known to occur. We have carried out a series of electrical resistivity and AC magnetic susceptibility measurements on BiTeI at pressure up to ∼40 GPa in an effort to characterize the properties of the high-pressure phases. A previous calculation found that the high-pressure orthorhombic P4/nmm structure BiTeI is a metal. We find that this structure is superconducting with T c values as high as 6 K. AC magnetic susceptibility measurements support the bulk nature of the superconductivity. Using electronic structure and phonon calculations, we compute T c and find that our data is consistent with phonon-mediated superconductivity.

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