933 research outputs found
Aluminium in Brain Tissue in Multiple Sclerosis.
Multiple sclerosis (MS) is a devastating and debilitating neurodegenerative disease of unknown cause. A consensus suggests the involvement of both genetic and environmental factors of which the latter may involve human exposure to aluminium. There are no data on the content and distribution of aluminium in human brain tissue in MS. The aluminium content of brain tissue from 14 donors with a diagnosis of MS was determined by transversely heated graphite furnace atomic absorption spectrometry. The location of aluminium in the brain tissue of two donors was investigated by aluminium-specific fluorescence microscopy. The aluminium content of brain tissue in MS was universally high with many tissues bearing concentrations in excess of 10 μg/g dry wt. (10 ppm) and some exceeding 50 ppm. There were no statistically significant relationships between brain lobes, donor age or donor gender. Aluminium-specific fluorescence successfully identified aluminium in brain tissue in both intracellular and extracellular locations. The association of aluminium with corpora amylacea suggests a role for aluminium in neurodegeneration in MS
Quantum lump dynamics on the two-sphere
It is well known that the low-energy classical dynamics of solitons of
Bogomol'nyi type is well approximated by geodesic motion in M_n, the moduli
space of static n-solitons. There is an obvious quantization of this dynamics
wherein the wavefunction evolves according to the Hamiltonian H_0 equal to
(half) the Laplacian on M_n. Born-Oppenheimer reduction of analogous mechanical
systems suggests, however, that this simple Hamiltonian should receive
corrections including k, the scalar curvature of M_n, and C, the n-soliton
Casimir energy, which are usually difficult to compute, and whose effect on the
energy spectrum is unknown. This paper analyzes the spectra of H_0 and two
corrections to it suggested by work of Moss and Shiiki, namely H_1=H_0+k/4 and
H_2=H_1+C, in the simple but nontrivial case of a single CP^1 lump moving on
the two-sphere. Here M_1=TSO(3), a noncompact kaehler 6-manifold invariant
under an SO(3)xSO(3) action, whose geometry is well understood. The symmetry
gives rise to two conserved angular momenta, spin and isospin. A hidden
isometry of M_1 is found which implies that all three energy spectra are
symmetric under spin-isospin interchange. The Casimir energy is found exactly
on the zero section of TSO(3), and approximated numerically on the rest of M_1.
The lowest 19 eigenvalues of H_i are found for i=0,1,2, and their spin-isospin
and parity compared. The curvature corrections in H_1 lead to a qualitatively
unchanged low-level spectrum while the Casimir energy in H_2 leads to
significant changes. The scaling behaviour of the spectra under changes in the
radii of the domain and target spheres is analyzed, and it is found that the
disparity between the spectra of H_1 and H_2 is reduced when the target sphere
is made smaller.Comment: 35 pages, 3 figure
Long‑term results of the augmented PFNA: a prospective multicenter trial
Producción CientíficaPertrochanteric fractures are increasing and
their operative treatment remains under discussion. Failures
needing reoperations such as a cut-out are reported to
be high and are associated with multiple factors including
poor bone quality, poor fracture reduction and improper
implant placement. The PFNA® with perforated blade
offers an option for standardized cement augmentation
with a PMMA cement to provide more stability to the
fracture fixation. It remains unclear if the augmentation
of this implant does any harm in a longer time span. This
prospective multicenter study shows clinical and radiological
results with this implant with a mean follow-up time of
15 months
Koalitionssignale bei der Bundestagswahl 2009 und deren Auswirkungen auf strategisches Wahlverhalten
Standardised cement augmentation of the PFNA using a perforated blade: A new technique and preliminary clinical results. A prospective multicentre trial
Producción CientíficaPertrochanteric fractures are a rising major health-care problem in the elderly and their operative
stabilisation techniques are still under discussion. Furthermore, complications like cut-out are reported
to be high and implant failure often is associated with poor bone quality. The PFNA1 with perforated
blade offers a possibility for standardised cement augmentation using a polymethylmethacrylate
(PMMA) cement which is injected through the perforated blade to enlarge the load-bearing surface and
to diminish the stresses on the trabecular bone. The current prospective multicentre study was
undertaken to evaluate the technical performance and the early clinical results of this new device.
In nine European clinics, 59 patients (45 female, mean age 84.5 years) suffering from an osteoporotic
pertrochanteric fracture (Arbeitsgemeinschaft fu¨ r Osteosynthesefragen, AO-31) were treated with the
augmented PFNA1. Primary objectives were assessment of operative and postoperative complications,
whereas activities of daily living, pain, mobility and radiologic parameters, such as cement distribution
around the blade and the cortical thickness index, were secondary objectives.
The mean follow-up time was 4 months where we observed callus healing in all cases. The surgical
complication rate was 3.4% with no complication related to the cement augmentation. More than onehalf
of the patients reached their prefracture mobility level within the study period. A mean volume of
4.2 ml of cement was injected. We did not find any cut-out, cut through, unexpected blade migration,
implant loosening or implant breakage within the study period.
Our findings lead us to conclude that the standardised cement augmentation using the perforated
blade for pertrochanteric fracture fixation enhances the implant anchorage within the head–neck
fragment and leads to good functional results
Reduced coronary flow reserve in Anderson-Fabry disease measured by transthoracic Doppler echocardiography
Coronary flow reserve was assessed in a patient with Anderson-Fabry disease complicated by symmetric left ventricular hypertrophy. Coronary flow reserve was measurable in all three major coronary arteries providing an opportunity to compare regional coronary flow reserve from different vascular beds. In this patient all the three vascular beds supplied diffusely hypertrophied myocardium. Coronary flow disturbances in small intramyocardial perforating arteries were visible. The coronary flow reserve was reduced to a similar level (around to 2.0) in all three major arteries. In our patient with Anderson-Fabry disease, the coronary vasodilatation was blunted in a diffuse pattern corresponding to the myocardial hypertrophy distribution. In small intramyocardial arteries coronary flow was also disturbed. Accordingly, retrograde systolic flow and accelerated anterograde diastolic flow were documented
Diamond Detectors for the TOTEM Timing Upgrade
This paper describes the design and the performance of the timing detector
developed by the TOTEM Collaboration for the Roman Pots (RPs) to measure the
Time-Of-Flight (TOF) of the protons produced in central diffractive
interactions at the LHC. The measurement of the TOF of the protons allows the
determination of the longitudinal position of the proton interaction vertex and
its association with one of the vertices reconstructed by the CMS detectors.
The TOF detector is based on single crystal Chemical Vapor Deposition (scCVD)
diamond plates and is designed to measure the protons TOF with about 50 ps time
precision. This upgrade to the TOTEM apparatus will be used in the LHC run 2
and will tag the central diffractive events up to an interaction pileup of
about 1. A dedicated fast and low noise electronics for the signal
amplification has been developed. The digitization of the diamond signal is
performed by sampling the waveform. After introducing the physics studies that
will most profit from the addition of these new detectors, we discuss in detail
the optimization and the performance of the first TOF detector installed in the
LHC in November 2015.Comment: 26 pages, 18 figures, 2 tables, submitted for publication to JINS
Evidence for non-exponential elastic proton-proton differential cross-section at low |t| and sqrt(s) = 8 TeV by TOTEM
The TOTEM experiment has made a precise measurement of the elastic
proton-proton differential cross-section at the centre-of-mass energy sqrt(s) =
8 TeV based on a high-statistics data sample obtained with the beta* = 90
optics. Both the statistical and systematic uncertainties remain below 1%,
except for the t-independent contribution from the overall normalisation. This
unprecedented precision allows to exclude a purely exponential differential
cross-section in the range of four-momentum transfer squared 0.027 < |t| < 0.2
GeV^2 with a significance greater than 7 sigma. Two extended parametrisations,
with quadratic and cubic polynomials in the exponent, are shown to be well
compatible with the data. Using them for the differential cross-section
extrapolation to t = 0, and further applying the optical theorem, yields total
cross-section estimates of (101.5 +- 2.1) mb and (101.9 +- 2.1) mb,
respectively, in agreement with previous TOTEM measurements.Comment: Final version published in Nuclear Physics
Bi-induced band gap reduction in epitaxial InSbBi alloys
The properties of molecular beam epitaxy-grown InSb1−xBix alloys are investigated. Rutherford backscattering spectrometry shows that the Bi content increases from 0.6% for growth at 350 °C to 2.4% at 200 °C. X-ray diffraction indicates Bi-induced lattice dilation and suggests a zinc-blende InBi lattice parameter of 6.626 Å. Scanning electron microscopy reveals surface InSbBi nanostructures on the InSbBi films for the lowest growth temperatures, Bi droplets at intermediate temperatures, and smooth surfaces for the highest temperature. The room temperature optical absorption edge was found to change from 172 meV (7.2 μm) for InSb to ∼88 meV (14.1 μm) for InSb0.976Bi0.024, a reduction of ∼35 meV/%Bi. The work at Liverpool and Warwick was supported by the University of Liverpool and the Engineering and Physical Sciences Research Council (EPSRC) under Grant Nos. EP/G004447/2 and EP/H021388/1. RBS measurements performed at Lawrence Berkeley National Lab were supported by the U.S. Department of Energy, Office of Science, Basic Energy Sciences, Materials Sciences and Engineering Division. Barry Karlin and Joe Woicik are thanked for use of the X24a HAXPES end station at the National Institute of Standards and Technology bending magnet beamline X24 at the National Synchrotron Light Source at Brookhaven National Laboratory. The National Synchrotron Light Source is supported by the U.S. Department of Energy, Contract No. DE-AC02-98CH10886. The work at Binghamton was supported by a Grant from State University of New York Research Foundation Collaboration Fund
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