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1.
Phys Rev Lett ; 118(13): 137701, 2017 Mar 31.
Artigo em Inglês | MEDLINE | ID: mdl-28409973

RESUMO

We investigate effects of quasiparticle poisoning in a Majorana island with strong tunnel coupling to normal-metal leads. In addition to the main Coulomb blockade diamonds, "shadow" diamonds appear, shifted by 1e in gate voltage, consistent with transport through an excited (poisoned) state of the island. Comparison to a simple model yields an estimate of parity lifetime for the strongly coupled island (∼1 µs) and sets a bound for a weakly coupled island (>10 µs). Fluctuations in the gate-voltage spacing of Coulomb peaks at high field, reflecting Majorana hybridization, are enhanced by the reduced lever arm at strong coupling. When converted from gate voltage to energy units, fluctuations are consistent with previous measurements.

2.
Phys Rev Lett ; 109(23): 236805, 2012 Dec 07.
Artigo em Inglês | MEDLINE | ID: mdl-23368241

RESUMO

We use electric dipole spin resonance to measure dynamic nuclear polarization in InAs nanowire quantum dots. The resonance shifts in frequency when the system transitions between metastable high and low current states, indicating the presence of nuclear polarization. We propose that the low and the high current states correspond to different total Zeeman energy gradients between the two quantum dots. In the low current state, dynamic nuclear polarization efficiently compensates the Zeeman gradient due to the g-factor mismatch, resulting in a suppressed total Zeeman gradient. We present a theoretical model of electron-nuclear feedback that demonstrates a fixed point in nuclear polarization for nearly equal Zeeman splittings in the two dots and predicts a narrowed hyperfine gradient distribution.

3.
Phys Rev Lett ; 105(13): 136803, 2010 Sep 24.
Artigo em Inglês | MEDLINE | ID: mdl-21230797

RESUMO

The persistent current in an ensemble of normal-metal rings shows Gaussian distributed sample-to-sample fluctuations with non-Gaussian corrections, which are precursors of the transition into the Anderson localized regime. We here report a calculation of the leading non-Gaussian correction to the current autocorrelation function, which is of third-order in the current. Although the third-order correlation function is small, inversely proportional to the dimensionless conductance g of the ring, the mere fact that it is nonzero is remarkable, since it is an odd moment of the current distribution.

4.
Science ; 212(4500): 1269-70, 1981 Jun 12.
Artigo em Inglês | MEDLINE | ID: mdl-17738834

RESUMO

Magnetotactic bacteria are present in fresh water and marine sediments of Fortaleza, Brazil, situated close to the geomagnetic equator. Both South-seeking and North-seeking bacteria are present in roughly equal numbers in the same samples. This observation is consistent with the hypothesis that the vertical component of the geomagnetic field selects the predominant polarity type among magnetotactic bacteria in natural environments.

5.
Contemp Clin Trials ; 84: 105817, 2019 09.
Artigo em Inglês | MEDLINE | ID: mdl-31344519

RESUMO

Adolescents with intellectual and developmental disabilities (IDD) are less physically active and have lower cardiovascular fitness compared with their typically developing peers. This population faces additional barriers to participation in moderate-to-vigorous physical activity (MVPA) such as reliance on parents, lack of peer-support, and lack of inclusive physical activity opportunities. Previous interventions to increase MVPA in adolescents with IDD have met with limited success, at least in part due to requiring parents to transport their adolescent to an exercise facility. We recently developed a remote system to deliver MVPA to groups of adolescents with IDD in their homes via video conferencing on a tablet computer. This approach eliminates the need for transportation and provides social interaction and support from both a health coach and other participants. We will conduct a 18-mo. trial (6 mos. active, 6 mos. maintenance, 6 mos. no-contact follow-up) to compare changes in objectively assessed MVPA in 114 adolescents with IDD randomized to a single level intervention delivered only to the adolescent (AO) or a multi-level intervention delivered to both the adolescent and a parent (A + P). Our primary aim is to compare increases in MVPA (min/d) between the AO and A + P groups from 0 to 6 mos. Secondarily we will compare changes in MVPA, sedentary time, cardiovascular fitness, muscular strength, motor ability, quality of life, and the percentage of adolescents achieving the US recommendation of 60 min. MVPA/d across 18 mos. We will also explore the influence of process variables/participant characteristics on changes in MVPA across 18 mos. NCT registration: NCT03684512.


Assuntos
Deficiências do Desenvolvimento/epidemiologia , Exercício Físico , Promoção da Saúde/métodos , Deficiência Intelectual/epidemiologia , Pais/educação , Adolescente , Criança , Computadores de Mão , Conhecimentos, Atitudes e Prática em Saúde , Nível de Saúde , Humanos , Pais/psicologia , Qualidade de Vida , Autoeficácia , Apoio Social , Fatores de Tempo , Comunicação por Videoconferência , Adulto Jovem
6.
Science ; 354(6319): 1557-1562, 2016 12 23.
Artigo em Inglês | MEDLINE | ID: mdl-28008065

RESUMO

Hybrid nanowires combining semiconductor and superconductor materials appear well suited for the creation, detection, and control of Majorana bound states (MBSs). We demonstrate the emergence of MBSs from coalescing Andreev bound states (ABSs) in a hybrid InAs nanowire with epitaxial Al, using a quantum dot at the end of the nanowire as a spectrometer. Electrostatic gating tuned the nanowire density to a regime of one or a few ABSs. In an applied axial magnetic field, a topological phase emerges in which ABSs move to zero energy and remain there, forming MBSs. We observed hybridization of the MBS with the end-dot bound state, which is in agreement with a numerical model. The ABS/MBS spectra provide parameters that are useful for understanding topological superconductivity in this system.

7.
Int J Antimicrob Agents ; 21(5): 441-5, 2003 May.
Artigo em Inglês | MEDLINE | ID: mdl-12727077

RESUMO

Telithromycin, the first ketolide antimicrobial to be developed for clinical use, has potent activity against group A beta-haemolytic streptococci (GABHS), including macrolide-resistant strains. The penetration of telithromycin into tonsils was assessed in 22 adults undergoing tonsillectomy at 3, 12 or 24 h after the fourth dose of oral telithromycin 800 mg once daily. Telithromycin rapidly penetrated tonsillar tissues, achieving a mean concentration of 3.95 mg/kg at 3 h post dose, 3.4 times greater than the corresponding plasma concentration (1.22 mg/l. The mean tonsil:plasma concentration ratio increased to 13.1 at 24 h post dose, indicating slower elimination from tonsils than plasma. Tonsillar and plasma concentrations exceeded the MIC(50) for GABHS throughout the 24-h dosing period. These findings suggest that telithromycin may be an effective new alternative treatment for GABHS tonsillopharyngitis.


Assuntos
Antibacterianos/farmacocinética , Cetolídeos , Macrolídeos , Tonsila Palatina/metabolismo , Tonsila Palatina/cirurgia , Tonsilectomia , Administração Oral , Adulto , Antibacterianos/administração & dosagem , Antibacterianos/efeitos adversos , Feminino , Humanos , Masculino , Testes de Sensibilidade Microbiana , Pessoa de Meia-Idade , Streptococcus pyogenes/efeitos dos fármacos
8.
Ann Otolaryngol Chir Cervicofac ; 99(6): 283-5, 1982.
Artigo em Francês | MEDLINE | ID: mdl-7125485

RESUMO

High dose Bacampicin given alone to 50 patients for obvious clinical manifestation of severe ENT infections proved most satisfactory, with rapid improvement in physical and general conditions. Samples from 21 patients showed presence of germs, all being sensitive to Bacampicin. No sign of intolerance was noted. It follows from this result that in cases with patent signs of severe ENT infections, 800 mg Bacampicin given along morning and evening provides an effective and well tolerated treatment.


Assuntos
Ampicilina/análogos & derivados , Otorrinolaringopatias/tratamento farmacológico , Adulto , Ampicilina/efeitos adversos , Ampicilina/uso terapêutico , Feminino , Humanos , Masculino , Pessoa de Meia-Idade
9.
Dynamis ; 16: 205-17, 1996.
Artigo em Espanhol | MEDLINE | ID: mdl-11624998

RESUMO

The creation of the Protomedicato of Castile by the Catholic Monarchs meant the persistence, in Catalonia, of the royal protophysicians of the ancient Crown of Aragon. The new institution gradually came to depend on the Protomedicato, and was completely assimilated during the XVIII century. Some well-defined periods are analyzed, ie, the persistence of direct royal appointments, a close relationship between the protophysicians and the College of Medical Doctors, and a clear influence of the Academy of Medicine during the last period of the 18th Century.


Assuntos
Academias e Institutos/história , Órgãos Governamentais/história , Licenciamento/história , Organização e Administração , Faculdades de Medicina/história , História do Século XV , História do Século XVI , História do Século XVII , História do Século XVIII , Relações Interinstitucionais , Espanha
10.
Food Chem ; 138(4): 2283-90, 2013 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-23497887

RESUMO

Heating-induced changes in meat proteins were investigated using models made of aqueous suspensions of myofibrils according to muscle fibre types and cellular compounds (oxidants and antioxidants). These changes were evaluated by measurements of carbonyl groups and protein surface hydrophobicity. Model results were compared to trial results obtained on pork meat (M. Longissimus dorsi) heated under the same conditions (45 and 75°C, from 5 to 120 min). Myofibrillar proteins from α-white fibres were more sensitive to oxidation and thermal denaturation than those from ß-red fibres. At 45°C, there were negligible differences due to peroxide or antioxidant types. At 75°C, organic peroxides (ROOH) were less oxidative than hydrogen peroxide (H2O2), and antioxidant enzymes were less efficient than vitamin E and carnosine at protecting proteins against oxidation. Protein oxidation observed in meat is lower than in the mimetic models and the increase in hydrophobicity remained limited in meat.


Assuntos
Antioxidantes/química , Carne/análise , Fibras Musculares Esqueléticas/química , Peróxidos/química , Animais , Culinária , Temperatura Alta , Cinética , Modelos Químicos , Proteínas Musculares/química , Oxirredução
11.
Meat Sci ; 94(3): 408-16, 2013 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-23566687

RESUMO

Three porcine muscles (Longissimus thoracis, Semitendinosus, Masseter), known to have large differences in biochemical and histological traits, were fully characterized and the link between muscle structure and quality evaluated. The oxidative Masseter had more pigment, higher content of metmyoglobin, haem iron, protein and collagen, and was redder with higher fibre numbers, fibre circularity, pH and water holding capacity than the glycolytic Longissimus. Fibre type distribution showed predominance of type IIB in Longissimus and Semitendinosus white, type I in Semitendinosus red and IIA in Masseter. Type I fibres were larger than type IIB and IIA in Semitendinosus and Masseter, respectively, but not in the Longissimus, indicating that fibre size is muscle dependent. Muscle redness was positively correlated with type I fibre traits, haem iron and metmyoglobin, and negatively associated with type II fibre characteristics, non-haem iron and oxymyoglobin. Expressible juice had positive correlation with fibre size and negative with fibre number and connective tissue.


Assuntos
Músculo Masseter/química , Músculo Masseter/ultraestrutura , Músculo Esquelético/ultraestrutura , Coxa da Perna/fisiologia , Animais , Glicólise , Concentração de Íons de Hidrogênio , Masculino , Microscopia/métodos , Fibras Musculares Esqueléticas/química , Fibras Musculares Esqueléticas/ultraestrutura , Músculo Esquelético/química , Suínos , Parede Torácica/química , Parede Torácica/ultraestrutura
12.
Nat Commun ; 2: 556, 2011 Nov 22.
Artigo em Inglês | MEDLINE | ID: mdl-22109530

RESUMO

Artificial molecules containing just one or two electrons provide a powerful platform for studies of orbital and spin quantum dynamics in nanoscale devices. A well-known example of these dynamics is tunnelling of electrons between two coupled quantum dots triggered by microwave irradiation. So far, these tunnelling processes have been treated as electric-dipole-allowed spin-conserving events. Here we report that microwaves can also excite tunnelling transitions between states with different spin. We show that the dominant mechanism responsible for violation of spin conservation is the spin-orbit interaction. These transitions make it possible to perform detailed microwave spectroscopy of the molecular spin states of an artificial hydrogen molecule and open up the possibility of realizing full quantum control of a two-spin system through microwave excitation.

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