369 research outputs found
The degeneration and destruction of femoral articular cartilage shows a greater degree of deterioration than that of the tibial and patellar articular cartilage in early stage knee osteoarthritis: a cross-sectional study
SummaryObjectiveThe aim of the present study was to examine whether the degenerative and morphological changes of articular cartilage in early stage knee osteoarthritis (OA) occurred equally for both femoral- and tibial- or patellar- articular cartilage using magnetic resonance imaging (MRI)-based analyses.DesignThis cross-sectional study was approved by the ethics committee of our university. Fifty patients with early stage painful knee OA were enrolled. The patients underwent 3.0 T MRI on the affected knee joint. Healthy volunteers who did not show MRI-based OA changes were also recruited as controls (n = 19). The degenerative changes of the articular cartilage were quantified by a T2 mapping analysis, and any structural changes were conducted using Whole Organ Magnetic Resonance Imaging Score (WORMS) technique.ResultsAll patients showed MRI-detected OA morphological changes. The T2 values of femoral condyle (FC) (P < 0.0001) and groove (P = 0.0001) in patients with early stage knee OA were significantly increased in comparison to those in the control, while no significant differences in the T2 values of patellar and tibial plateau (TP) were observed between the patients and the control. The WORMS cartilage and osteophyte scores of the femoral articular cartilage were significantly higher than those in the patellar- (P = 0.001 and P = 0.007, respectively) and tibial- (P = 0.0001 and P < 0.0001, respectively) articular cartilage in the patients with early stage knee OA.ConclusionsThe degradation and destruction of the femoral articular cartilage demonstrated a greater degree of deterioration than those of the tibial- and patellar- articular cartilage in patients with early stage knee OA
Spin-Polarized Transprot through Double Quantum Dots
We investigate spin-polarized transport phenomena through double quantum dots
coupled to ferromagnetic leads in series. By means of the slave-boson
mean-field approximation, we calculate the conductance in the Kondo regime for
two different configurations of the leads: spin-polarization of two
ferromagnetic leads is parallel or anti-parallel. It is found that transport
shows some remarkable properties depending on the tunneling strength between
two dots. These properties are explained in terms of the Kondo resonances in
the local density of states.Comment: 8 pages, 11 figure
Scientific Drilling and Related Research in the Samail Ophiolite, Sultanate of Oman
This workshop report describes plans for scientific drilling in the Samail ophiolite in Oman in the context of past, current, and future research. Long-standing plans to study formation and evolution of the Samail crust and upper mantle, involving igneous and metamorphic processes at an oceanic spreading center, have been augmented by recent interest in ongoing, low temperature processes. These include alteration and weathering, and the associated sub-surface biosphere supported by chemical potential energy due to disequilibrium between mantle peridotite and water near the surface. This interest is motivated in part by the possibility of geological carbon capture and storage via engineered, accelerated mineral carbonation in Oman
Long-range transfer of electron-phonon coupling in oxide superlattices
The electron-phonon interaction is of central importance for the electrical
and thermal properties of solids, and its influence on superconductivity,
colossal magnetoresistance, and other many-body phenomena in
correlated-electron materials is currently the subject of intense research.
However, the non-local nature of the interactions between valence electrons and
lattice ions, often compounded by a plethora of vibrational modes, present
formidable challenges for attempts to experimentally control and theoretically
describe the physical properties of complex materials. Here we report a Raman
scattering study of the lattice dynamics in superlattices of the
high-temperature superconductor and the
colossal-magnetoresistance compound that suggests
a new approach to this problem. We find that a rotational mode of the MnO
octahedra in experiences pronounced
superconductivity-induced lineshape anomalies, which scale linearly with the
thickness of the layers over a remarkably long range of
several tens of nanometers. The transfer of the electron-phonon coupling
between superlattice layers can be understood as a consequence of long-range
Coulomb forces in conjunction with an orbital reconstruction at the interface.
The superlattice geometry thus provides new opportunities for controlled
modification of the electron-phonon interaction in complex materials.Comment: 13 pages, 4 figures. Revised version to be published in Nature
Material
Allergic enterocolitis and protein-losing enteropathy as the presentations of manganese leak from an ingested disk battery: A case report
<p>Abstract</p> <p>Introduction</p> <p>Disk battery ingestions can lead to serious complications including airway or digestive tract perforation, blood vessel erosions, mediastinitis, and stricture formation.</p> <p>Case presentation</p> <p>We report a 20-month-old Caucasian child who developed eosinophilic enterocolitis and subsequent protein-losing enteropathy from manganese that leaked from a lithium disk battery. The disk battery was impacted in her esophagus for 10 days resulting in battery corrosion. We postulate that this patient's symptoms were due to a manganese leak from the 'retained' disk battery; this resulted in an allergic response in her gut and protein-losing enteropathy. Her symptoms improved gradually over the next 2 weeks with conservative management.</p> <p>Conclusion</p> <p>This is the first case report to highlight the potential complication of allergic enterocolitis and protein-losing enteropathy secondary to ingested manganese. Clinicians should be vigilant about this rare complication in managing patients with disk battery ingestions.</p
Resonance Kondo Tunneling through a Double Quantum Dot at Finite Bias
It is shown that the resonance Kondo tunneling through a double quantum dot
(DQD) with even occupation and singlet ground state may arise at a strong bias,
which compensates the energy of singlet/triplet excitation. Using the
renormalization group technique we derive scaling equations and calculate the
differential conductance as a function of an auxiliary dc-bias for parallel DQD
described by SO(4) symmetry. We analyze the decoherence effects associated with
the triplet/singlet relaxation in DQD and discuss the shape of differential
conductance line as a function of dc-bias and temperature.Comment: 11 pages, 6 eps figures include
Kondo effect in systems with dynamical symmetries
This paper is devoted to a systematic exposure of the Kondo physics in
quantum dots for which the low energy spin excitations consist of a few
different spin multiplets . Under certain conditions (to be
explained below) some of the lowest energy levels are nearly
degenerate. The dot in its ground state cannot then be regarded as a simple
quantum top in the sense that beside its spin operator other dot (vector)
operators are needed (in order to fully determine its quantum
states), which have non-zero matrix elements between states of different spin
multiplets . These "Runge-Lenz"
operators do not appear in the isolated dot-Hamiltonian (so in some sense they
are "hidden"). Yet, they are exposed when tunneling between dot and leads is
switched on. The effective spin Hamiltonian which couples the metallic electron
spin with the operators of the dot then contains new exchange terms,
beside the ubiquitous ones . The operators and generate a
dynamical group (usually SO(n)). Remarkably, the value of can be controlled
by gate voltages, indicating that abstract concepts such as dynamical symmetry
groups are experimentally realizable. Moreover, when an external magnetic field
is applied then, under favorable circumstances, the exchange interaction
involves solely the Runge-Lenz operators and the corresponding
dynamical symmetry group is SU(n). For example, the celebrated group SU(3) is
realized in triple quantum dot with four electrons.Comment: 24 two-column page
- …