446 research outputs found
Cotunneling-mediated transport through excited states in the Coulomb blockade regime
We present finite bias transport measurements on a few-electron quantum dot.
In the Coulomb blockade regime, strong signatures of inelastic cotunneling
occur which can directly be assigned to excited states observed in the
non-blockaded regime. In addition, we observe structures related to sequential
tunneling through the dot, occuring after it has been excited by an inelastic
cotunneling process. We explain our findings using transport calculations
within the real-time Green's function approach, including diagrams up to fourth
order in the tunneling matrix elements.Comment: 4 pages, 3 figure
Dressing preserving the fundamental group
In this note we consider the relationship between the dressing action and the
holonomy representation in the context of constant mean curvature surfaces. We
characterize dressing elements that preserve the topology of a surface and
discuss dressing by simple factors as a means of adding bubbles to a class of
non finite type cylinders.Comment: 36 pages, 1 figur
La acetabuloplastia de Staheli en el tratamiento de la enfermedad de Legg-Calvé-Perthes en mayores de 6 años. Estudio preliminar
Objetivo: Valorar los resultados funcionales y radiográficos de la acetabuloplastia de Staheli como
alternativa terapéutica en el tratamiento quirúrgico de la enfermedad de Legg-Calvé-Perthes de debut tardÃo.Material
y método: Estudio retrospectivo de 7 pacientes con enfermedad de Legg-Calvé-Perthes tratados mediante
acetabuloplastia de Staheli con un tiempo de seguimiento medio de tres años y tres meses. Se analizan parámetros
clÃnicos (movilidad prequirúrgica y al final del seguimiento) asà como parámetros radiográficos (clasificación
de Herring, Ãndice acetábulo-cabeza de Heyman-Herndon y el ángulo centro-borde de Wiberg) previos al tratamiento
quirúrgico, tras el tratamiento quirúrgico y al final del seguimiento. Resultados: Tras el análisis estadÃstico
de los Ãndices radiográficos (Ãndice acetábulo-cabeza de Heyman-Herndon asà como ángulo de Wiberg) se
objetivaron diferencias estadÃsticamente significativas entre la radiografÃa prequirúrgica y postquirúrgica, pero
no se objetivaron diferencias estadÃsticamente significativas entre la postquirúrgica y la realizada al final del
seguimiento. Por lo tanto, los Ãndices radiográficos mostraron una mejora en sus parámetros que además se mantuvo
estable en el tiempo. Ningún paciente presentó complicaciones debidas a la cirugÃa. La exploración fÃsica
mostró una mejorÃa media de 10º en la rotación interna de la cadera. Conclusiones: La técnica de acetabuloplastia
según Staheli es una opción quirúrgica que conduce a la mejora de los resultados radiográficos y funcionales con
pocas complicaciones debidas al procedimiento.Objective: To evaluate the functional and radiographic results of Staheli's acetabuloplasty as therapeutic
option in the surgical treatment of Legg-Calvé-Perthes's disease of late debut. Material and method:
we did a retrospective study of seven patients with Legg-Calvé-Perthes's disease treated by means of Staheli's
acetabuloplasty with an average follow-up of three years and three months. We analyzed clinical parameters
(preoperative and "end of the follow-up" mobility) as well as radiographic parameters (Herring's classification,
Heyman-Herndon's index and Wiberg's center-edge angle) before the surgical treatment, after the surgical treatment
and at the end of the follow-up. Results: Any patients presented complications due to the surgery. The physical
exploration showed an average improvement of 10º in the internal rotation of the hip. After the statistical
analysis of the radiographic indexes (Heyman-Herndon's index as well as Wiberg's angle), there were statistically
significant differences between the preoperative X-ray and the postoperative one, but there were no statistically
significant differences between the postoperative one and the X-ray done at the end of the follow-up. Therefore,
the radiographic indexes showed an improvement in these parameters that in addition kept stable in time. Conclusions:
The technic of acetabuloplasty according to Staheli is a surgical option that leads to a good radiographic
and functional result with few complications due to the procedure
LET-Dependent Low Dose and Synergistic Inhibition of Human Angiogenesis by Charged Particles: Validation of miRNAs that Drive Inhibition
Space radiation inhibits angiogenesis by two mechanisms depending on the linear energy transfer (LET). Using human 3D micro-vessel models, blockage of the early motile stage of angiogenesis was determined to occur after exposure to low LET ions (/AMU), whereas inhibition of the later stages occurs after exposure to high LET ions (\u3e8 KeV/AMU). Strikingly, the combined effect is synergistic, detectible as low as 0.06 Gy making mixed ion space radiation more potent. Candidates for bystander transmission are microRNAs (miRNAs), and analysis on miRNA-seq data from irradiated mice shows that angiogenesis would in theory be downregulated. Further analysis of three previously identified miRNAs showed downregulation of their targets associated with angiogenesis and confirmed their involvement in angiogenesis pathways and increased health risks associated with cardiovascular disease. Finally, synthetic molecules (antagomirs) designed to inhibit the predicted miRNAs were successfully used to reverse the inhibition of angiogenesis
100 Hz ROCS microscopy correlated with fluorescence reveals cellular dynamics on different spatiotemporal scales
Fluorescence techniques dominate the field of live-cell microscopy, but bleaching and motion blur from too long integration times limit dynamic investigations of small objects. High contrast, label-free life-cell imaging of thousands of acquisitions at 160 nm resolution and 100 Hz is possible by Rotating Coherent Scattering (ROCS) microscopy, where intensity speckle patterns from all azimuthal illumination directions are added up within 10 ms. In combination with fluorescence, we demonstrate the performance of improved Total Internal Reflection (TIR)-ROCS with variable illumination including timescale decomposition and activity mapping at five different examples: millisecond reorganization of macrophage actin cortex structures, fast degranulation and pore opening in mast cells, nanotube dynamics between cardiomyocytes and fibroblasts, thermal noise driven binding behavior of virus-sized particles at cells, and, bacterial lectin dynamics at the cortex of lung cells. Using analysis methods we present here, we decipher how motion blur hides cellular structures and how slow structure motions cover decisive fast motions
Free energy and molecular dynamics calculations for the cubic-tetragonal phase transition in zirconia
The high-temperature cubic-tetragonal phase transition of pure stoichiometric
zirconia is studied by molecular dynamics (MD) simulations and within the
framework of the Landau theory of phase transformations. The interatomic forces
are calculated using an empirical, self-consistent, orthogonal tight-binding
(SC-TB) model, which includes atomic polarizabilities up to the quadrupolar
level. A first set of standard MD calculations shows that, on increasing
temperature, one particular vibrational frequency softens. The temperature
evolution of the free energy surfaces around the phase transition is then
studied with a second set of calculations. These combine the thermodynamic
integration technique with constrained MD simulations. The results seem to
support the thesis of a second-order phase transition but with unusual, very
anharmonic behaviour above the transition temperature
Fibrous Monolithic Ceramics: III, Mechanical Properties and Oxidation Behavior of the Silicon Carbide/Boron Nitride System
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/66176/1/j.1151-2916.1994.tb05399.x.pd
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