898 research outputs found
Quantum corrections to the effective neutrino mass operator in 5D MSSM
We discuss in detail a five-dimensional Minimal Supersymmetric Standard Model
compactified on extended by the effective Majorana neutrino mass
operator. We study the evolution of neutrino masses and mixings. Masses and
angles, in particular the atmospheric mixing angle , can be
significantly lowered at high energies with respect to their value at low
energy.Comment: 23 pages, 13 figure
Dynamic optical coherence tomography. a non-invasive imaging tool for the distinction of nevi and melanomas
Along with the rising melanoma incidence in recent decades and bad prognoses resulting from late diagnoses, distinguishing between benign and malignant melanocytic lesions has become essential. Unclear cases may require the aid of non-invasive imaging to reduce unnecessary biopsies. This multicentric, case-control study evaluated the potential of dynamic optical coherence tomography (D-OCT) to identify distinguishing microvascular features in nevi. A total of 167 nevi, including dysplastic ones, on 130 participants of all ages and sexes were examined by D-OCT and dermoscopy with a histological reference. Three blinded analyzers evaluated the lesions. Then, we compared the features to those in 159 melanomas of a prior D-OCT study and determined if a differential diagnosis was possible. We identified specific microvascular features in nevi and a differential diagnosis of melanomas and nevi was achieved with excellent predictive values. We conclude that D-OCT overcomes OCT´s inability to distinguish melanocytic lesions based on its focus on microvascularization. To determine if an addition to the gold standard of a clinical-dermoscopic examination improves the diagnosis of unclear lesions, further studies, including a larger sample of dysplastic nevi and artificial intelligence, should be conducted
Pharmacokinetic and pharmacodynamic characterization of a mediummolecularweight heparin in comparison with UFH and LMWH.
Despite the well-established medical use of heparins, the question arises whether the efficacy-safety ratio of the available heparins can still be improved. Therefore, a medium-molecular-weight heparin (MMWH), a new heparin with an average molecular weight of 10.5 kDa and a narrow molecular weight range (9.5 to 11.5 kDa) was developed. Its in vitro activities amount to 174.9 anti-factor Xa (aXa) U/mg and 170.0 antithrombin (aIIa) U/mg. In the presented randomized, double-blind, cross-over study in healthy volunteers, the pharmacokinetics and pharmacodynamics of MMWH are compared with those of an unfractionated heparin (UFH) and a low-molecular-weight heparin (LWMH; enoxaparin). After subcutaneous administration of 9000 aXa-U of either heparin in 16 volunteers, the prolongation of the activated partial thromboplastin time (aPTT), the aXa activity, and the aIIa activities were determined at 11 time points spread over 24 hours after injection. The ex vivo analysis revealed striking pharmacodynamic and pharmacokinetic differences between the three heparins. UFH had the lowest bioavailability regarding the aPTT, aXa, and aIIa activities. Enoxaparin exhibited only low aIIa activity but the highest aXa activity. Unlike UFH and enoxaparin, MMWH showed a high recovery of aIIa activity, which suggests that it combines the high potency to inhibit thrombin that characterizes UFH with the high bioavailability of the LMWHs. Consequently, substantially lower doses are needed to bring about effects comparable to those of UFH and LMWH
High pressure study of BaFe2As2 - role of hydrostaticity and uniaxial stress
We investigate the evolution of the electrical resistivity of BaFe2As2 single
crystals with pressure. The samples used were from the same batch grown from
self flux and showed properties that were highly reproducible. Samples were
pressurised using three different pressure media: pentane-isopentane (in a
piston cylinder cell), Daphne oil (in an alumina anvil cell) and steatite (in a
Bridgman cell). Each pressure medium has its own intrinsic level of
hydrostaticity, which dramatically affects the phase diagram. An increasing
uniaxial pressure component in this system quickly reduces spin density wave
order and favours the appearance of superconductivity, similar to what is seen
in SrFe2As2.Comment: 11 page
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