1,963 research outputs found
Experimental constraints on the parameter space of the next-to-minimal supersymmetric standard model at LEP 2
We search for the neutral Higgs sector of the next-to-minimal supersymmetric
standard model at LEP 2. At the tree level any experimental constraints on
cannot be set by the Higgs search at LEP 2 with = 175
GeV, whereas at LEP 2 with = 192 GeV can be set by an
experimental constraint. Furthermore the tree level parameter space of the
model can be completely explored by the Higgs search at LEP 2 with =
205 GeV. Radiative corrections both to the neutral Higgs boson masses and to
the relevant couplings for the scalar Higgs productions give large
contributions to the production cross sections of the scalar Higgs bosons at
the tree level. The tree level situation at LEP 2 with = 192 GeV as
well as with = 205 GeV can be drastically changed by these effects.
We expect that a small region of the 1-loop level parameter space of the model
via the scalar Higgs production can be explored by the Higgs search at LEP 2.Comment: 14 pages (3 figures are included
Polyethylene wear particles play a role in development of osteoarthritis via detrimental effects on cartilage, meniscus, and synovium
SummaryObjectiveWhile ultra-high molecular weight polyethylene (UHMWPE) wear particles are known to cause periprosthetic osteolysis, its interaction with other intra-articular tissues in the case of partial joint arthroplasties is not well understood. We hypothesized that UHMWPE particles per se would interact with intra-articular tissue, which by acting as inflammatory reservoirs, would subsequently induce osteoarthritic (OA) changes. Our goal was to assess the inflammatory response, phagocytic activity, as well as apoptosis of intra-articular cells in the presence of UHMWPE particles in vitro, and the in vivo response of those tissues after intra-articular injection of particles in a murine model.DesignThree cell types were used for the in vitro study; chondrocytes, meniscal fibrochondrocytes, and synoviocytes. Each cell type was cultured with two different concentrations of UHMWPE particles. Pro-inflammatory cytokine production, phagocytosis, and apoptosis were analyzed. In vivo experiments were done by injecting two concentrations of UHMWPE particles into normal and murine OA model knee joints.ResultsIn vitro experiments showed that UHMWPE particles increase pro-inflammatory cytokine and mediator (IL-1β, IL-6, TNF-α, Nitric Oxide, and Prostaglandin E2) production, phagocytosis of particles, and apoptosis in all cell types. In vivo experiment showed degeneration of cartilage and meniscus, as well as synovitis after particle injection.ConclusionsUHMWPE wear particles per se exert detrimental effects in cartilage, synovium, and meniscus of the knee joint resulting in pro-inflammatory cytokine release, phagocytosis of particles and apoptosis. Particles induced and exacerbated OA changes in a murine model
Asymmetry sum rule for molecular predissociation
© 2000 American Physical SocietyIn the case of weak diatomic molecular predissociation by noninteracting, optically inactive continuum states, it is demonstrated that the predissociation line shape is more accurately represented by a Beutler-Fano profile than by a Lorentzian. The weak asymmetry that is found to occur is due principally to interactions with neighboring vibrational resonances. For this type of predissociation in the case of multiple continua, a sum rule for the corresponding line-shape asymmetry is derived. This sum rule is verified numerically using single-channel and multichannel coupled Schrödinger-equation calculations for the Schumann-Runge band system of O2. Similar results are presented for the case of optically active continua.F. T. Hawes, L. W. Torop, B. R. Lewis and S. T. Gibso
Channeling in direct dark matter detection I: channeling fraction in NaI (Tl) crystals
The channeling of the ion recoiling after a collision with a WIMP changes the
ionization signal in direct detection experiments, producing a larger signal
than otherwise expected. We give estimates of the fraction of channeled
recoiling ions in NaI (Tl) crystals using analytic models produced since the
1960's and 70's to describe channeling and blocking effects. We find that the
channeling fraction of recoiling lattice nuclei is smaller than that of ions
that are injected into the crystal and that it is strongly temperature
dependent.Comment: 37 pages, 35 figures, Accepted for publication in JCAP on 27 October
2010, Minor revisions: added an appendix, updated references, updated Fig. 9,
corrected a few typo
Prognostic Value of Electrophysiological Parameters for the Recovery of Motor Functions in Stroke Patients
We estimated correlations between baseline electrophysiological parameters and motor
functions in patients with subacute stroke, in order to identify their predictive value for motor
and functional recovery after a 4-week-long rehabilitation period. Sixty patients with subacute
stroke were enrolled. Somatosensory evoked potentials (SSEPs), compound motor action
potentials (CMAPs), and sensory nerve action potentials (SNAPs) were recorded, and the
amplitude ratios were calculated in the components of these potentials. Clinical parameters
consisted of the Korean-modified Barthel index (K-MBI), motricity index (MI), and manual
function test (MFT). After the rehabilitation period, these indices were re-evaluated. The
ulnar CMAP amplitude was found to significantly correlate with all clinical outcome indices.
Additionally, a multivariate linear regression analysis revealed that the ulnar CAMP amplitude
ratio was an independent predictor for the baseline MI of the upper extremity and K-MBI.
The median SSEP amplitude ratio was an independent prognostic factor for the follow-up
MI of the upper extremity, MFT, and follow-up K-MBI. Our results indicate that not only is
the median SSEP amplitude ratio a prognostic factor for the motor functions and functional
recovery, but also the ulnar CMAP amplitude might be an independent predictor in subacute
stroke patients.Ми оцінювали кореляції між вихідними електрофізіологічними параметрами та моторними функціями у пацієнтів із
підгострим інсультом з ціллю ідентифікувати прогностичну цінність цих даних для моторного та функціонального
відновлення після чотиритижневого періоду реабілітації.
Відводили соматосенсорні викликані потенціали (SSEP),
складні моторні потенціали дії (CMAP) та складні сенсорні
нервові потенціали дії (SNAP); розраховували відношення
амплітуд цих потенціалів та їх компонентів. Серед клінічних параметрів оцінювали індекс Бартела, модифікований
для умов Кореї (K-MBI), індекс моторної сфери (MI) та тест
мануальних функцій (MFT). Ці індекси повторно оцінювалися після періоду реабілітації. Амплітуда CMAP, викликаних стимуляцією ульнарного нерва, вірогідно корелювала з
усіма клінічними показниками. Крім того, аналіз мультиваріативної лінійної регресії показав, що відношення амплітуд ульнарних CAMP є незалежним предиктором вихідного
MI для верхньої кінцівки та K-MBI. Відношення амплітуд
SSEP, викликаних стимуляцією медіанного нерва, було незалежним прогностичним фактором для післяреабілітаційного MI верхніх кінцівок, MFT і післяреабілітаційного K-MBI.
Наші результати свідчать про те, що не тільки відношення
амплітуд медіанних SSEP є прогностичним фактором щодо
моторних функцій та функціонального відновлення; амплітуда ульнарних CMAP теж може бути незалежним предиктором у пацієнтів із підгострим інсультом
Thermoelectric effects of an Aharonov-Bohm interferometer with an embedded quantum dot in the Kondo regime
Thermoelectric effects are studied in an Aharonov-Bohm (AB) interferometer
with an embedded quantum dot in the Kondo regime. The AB flux-dependent
transmission probability has an asymmetrical shape arising from the Fano
interference between the direct tunneling path and the Kondo-resonant tunneling
path through a quantum dot. The sign and magnitude of thermopower can be
modulated by the AB flux and the direct tunneling amplitude. In addition, the
thermopower is anomalously enhanced by the Kondo correlation in the quantum dot
near the Kondo temperature (). The Kondo correlation in the quantum dot
also leads to crossover behavior in diagonal transport coefficients as a
function of temperature. The amplitude of an AB oscillation in electric and
thermal conductances is small at temperatures far above , but becomes
enhanced as the system is cooled below . The AB oscillation is strong in
the thermopower and Lorenz number within the crossover region near the Kondo
temperature.Comment: 16 pages, 10 figure
Spontaneous parity violation and minimal Higgs models
In this paper we present a model for the spontaneous breaking of parity with
two Higgs doublets and two neutral Higgs singlets which are even and odd under
D-parity. The condition can be satisfied without introducing
bidoublets and it is induced by the breaking of D-parity through the vacuum
expectation value of the odd Higgs singlet. Examples of left-right symmetric
and mirror fermions models in grand unified theories are presented.Comment: Revised version. Accepted in Eur. Phys. Journal
Fractal Properties of Robust Strange Nonchaotic Attractors in Maps of Two or More Dimensions
We consider the existence of robust strange nonchaotic attractors (SNA's) in
a simple class of quasiperiodically forced systems. Rigorous results are
presented demonstrating that the resulting attractors are strange in the sense
that their box-counting dimension is N+1 while their information dimension is
N. We also show how these properties are manifested in numerical experiments.Comment: 9 pages, 14 figure
Renal crystal deposits and histopathology in patients with cystine stones
We have biopsied the papillae of patients who have cystine stones asking if this stone type is associated with specific tissue changes. We studied seven cystine stone formers (SF) treated with percutaneous nephrolithotomy using digital video imaging of renal papillae for mapping and obtained papillary biopsies. Biopsies were analyzed by routine light and electron microscopy, infrared spectroscopy, electron diffraction, and micro-CT. Many ducts of Bellini (BD) had an enlarged ostium, and all such were plugged with cystine crystals, and had injured or absent lining cells with a surrounding interstitium that was inflamed to fibrotic. Crystal plugs often projected into the urinary space. Many inner medullary collecting ducts (IMCD) were dilated with or without crystal plugging. Apatite crystals were identified in the lumens of loops of Henle and IMCD. Abundance of interstitial Randall's plaque was equivalent in amount to that of non-SF. In the cortex, glomerular obsolescence and interstitial fibrosis exceeded normal. Cystine crystallizes in BD with the probable result of cell injury, interstitial reaction, nephron obstruction, and with the potential of inducing cortical change and loss of IMCD tubular fluid pH regulation, resulting in apatite formation. The pattern of IMCD dilation, and loss of medullary structures is most compatible with such obstruction, either from BD lumen plugs or urinary tract obstruction from stones themselves
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