993 research outputs found
ΠΠΎΠ²ΡΠ΅ ΠΊΠ»ΠΈΠ½ΠΈΡΠ΅ΡΠΊΠΈΠ΅ ΠΈ Π΄ΠΈΠ°Π³Π½ΠΎΡΡΠΈΡΠ΅ΡΠΊΠΈΠ΅ ΡΡΡΠ°ΡΠ΅Π³ΠΈΠΈ ΠΏΡΠΈ ΡΠ°ΠΊΠ΅ ΠΏΠΎΡΠΊΠΈ
ΠΡΠ΅Π΄ΡΡΠ°Π²Π»Π΅Π½ Π°Π½Π°Π»ΠΈΠ· ΠΈΠ·ΠΌΠ΅Π½ΠΈΠ²ΡΠ΅ΠΉΡΡ ΠΊΠ»ΠΈΠ½ΠΈΠΊΠΈ ΠΎΠΏΡΡ
ΠΎΠ»Π΅ΠΉ ΠΏΠΎΡΠΊΠΈ. ΠΠΏΠΈΡΠ°Π½Ρ Π΄ΠΈΠ½Π°ΠΌΠΈΠΊΠ° ΠΈ ΠΏΠΎΡΠ»Π΅Π΄ΠΎΠ²Π°ΡΠ΅Π»ΡΠ½ΠΎΡΡΡ ΠΈΡΠΏΠΎΠ»ΡΠ·ΠΎΠ²Π°Π½ΠΈΡ Π½ΠΎΠ²ΡΡ
Π²ΠΈΠ·ΡΠ°Π»ΠΈΠ·ΠΈΡΡΡΡΠΈΡ
ΠΌΠ΅ΡΠΎΠ΄ΠΎΠ² Π΄ΠΈΠ°Π³Π½ΠΎΡΡΠΈΠΊΠΈ.The analysis of the changed clinical picture of renal tumors is done. The dynamics and sequence of the new imaging techniques are described
Anisotropic properties of MgB2 by torque magnetometry
Anisotropic properties of superconducting MgB2 obtained by torque
magnetometry are compared to theoretical predictions, concentrating on two
issues. Firstly, the angular dependence of Hc2 is shown to deviate close to Tc
from the dependence assumed by anisotropic Ginzburg-Landau theory. Secondly,
from the evaluation of torque vs angle curves it is concluded that the
anisotropy of the penetration depth gamma_lambda has to be substantially higher
at low temperature than theoretical estimates, at least in fields higher than
0.2 T.Comment: 2 p.,2 Fig., submitted to Physica C (M2S-Rio proceedings); v2: 1 ref
adde
Reply to ``Comment on `Magnetic field effects on neutron diffraction in the antiferromagnetic phase of '''
Fak, van Dijk and Wills (FDW) question our interpretation of elastic
neutron-scattering experiments in the antiferromagnetic phase of UPt_3. They
state that our analysis is incorrect because we average over magnetic
structures that are disallowed by symmetry. We disagree with FDW and reply to
their criticism. FDW also point out that we have mistaken the magnetic field
direction in the experiment reported by N. H. van Dijk et al. [Phys. Rev. B 58,
3186 (1998)]. We correct this error and note that our previous conclusion is
also valid for the correct field orientation.Comment: 3 page
Binaphthyl-1,2,3-triazole peptidomimetics with activity against Clostridium difficile and other pathogenic bacteria
Clostridium difficile (C. difficile) is a problematic Gram positive bacterial pathogen causing moderate to severe gastrointestinal infections. Based on a lead binaphthyl-tripeptide dicationic antimicrobial, novel mono-, di- and tri-peptidomimetic analogues targeting C. difficile were designed and synthesized incorporating one, two or three d-configured cationic amino acid residues, with a common 1,2,3-triazole ester isostere at the C-terminus. Copper- and ruthenium-click chemistry facilitated the generation of a 46 compound library for in vitro bioactivity assays, with structure-activity trends over the largest compound subset revealing a clear advantage to triazole-substitution with a linear or branched hydrophobic group. The most active compounds were dicationic-dipeptides where the triazole was substituted with a 4- or 5-cyclohexylmethyl or 4,5-diphenyl moiety, providing MICs of 4 ΞΌg mL-1 against three human isolates of C. difficile. Further biological screening revealed significant antimicrobial activity for several compounds against other common bacterial pathogens, both Gram positive and negative, including S. aureus (MICs β₯2 ΞΌg mL-1), S. pneumoniae (MICs β₯1 ΞΌg mL-1), E. coli (MICs β₯4 ΞΌg mL-1), A. baumannii (MICs β₯4 ΞΌg mL-1) and vancomycin-resistant E. faecalis (MICs β₯4 ΞΌg mL-1)
Broadening of band-gap in photonic crystals with optically saturated media
Due to strong absorption of the incident light, the media with high
refractive index are considered restrictive for applications in photonic
crystals (PhCs). The possibility to resolve this problem by optical saturation
effectively minimizing the absorption of the PhC medium is discussed. Such
approach might be promising for the significant broadening of the photonic
band-gap.Comment: 10 page
Surface superconductivity and order parameter suppression in UPt
We show that a recent measurement of surface superconductivity in UPt
(Keller {\it et. al.}, Phys. Rev. Lett. {\bf 73}, 2364 (1994)) can be
understood if the superconducting pair wavefunction is suppressed
anisotropically at a vacuum to superconductor interface. Further measurements
of surface superconductivity can distinguish between the various
phenomenological models of superconducting UPt.Comment: 4 pages, latex, 2 Figures available upon request
([email protected]
Anisotropy of the superconducting state properties and phase diagram of MgB2 by torque magnetometry on single crystals
The angular and temperature dependence of the upper critical field Hc2 in
MgB2 was determined from torque magnetometry measurements on single crystals.
The Hc2 anisotropy gamma_H was found to decrease with increasing temperature,
in disagreement with the anisotropic Ginzburg-Landau theory, which predicts
that the gamma_H is temperature independent. This behaviour can be explained by
the two band nature of superconductivity in MgB2. An analysis of measurements
of the reversible torque in the mixed state yields a field dependent effective
anisotropy gamma_eff, which can be at least partially explained by different
anisotropies of the penetration depth and the upper critical field. It is shown
that a peak effect in fields of about 0.85 Hc2 is a manifestation of an
order-disorder phase transition of vortex matter. The H-T phase diagram of MgB2
for H//c correlates with the intermediate strength of thermal fluctuations in
MgB2, as compared to those in high and low Tc superconductors.Comment: 12 pages, 8 figures, Physica C in print (invited paper for a special
issue on MgB2
Neural multimodal integration underlying synchronization with a co-performer in music: influences of motor expertise and visual information
Sensorimotor synchronization is a general skill that musicians have developed to the highest levels of performance, including synchronization in timing and articulation. This study investigated neurocognitive processes that enable such high levels of performance, specifically testing the relevance of 1) motor resonance and sharing high levels of motor expertise with the co-performer, and 2) the role of visual information in addition to auditory information. Musicians with varying levels of piano expertise (including non-pianists) performed on a single piano key with their right hand along with recordings of a pianist who performed simple melodies with the left hand, synchronizing timing and articulation. The prerecorded performances were presented as audio-only, audio-video, or audio-animation stimuli. Double pulse Transcranial Magnetic Stimulation (dTMS) was applied to test the contribution of the right dorsal premotor cortex (dPMC), an area implicated in motor resonance with observed (left-hand) actions, and the contribution of the right intraparietal sulcus (IPS), an area known for multisensory binding. Results showed effects of dTMS in the conditions that included visual information. IPS stimulation improved synchronization ability, although this effect was found to reverse for the video condition with higher levels of relevant motor expertise. dPMC stimulation improved or worsened synchronization ability. Level of relevant motor expertise was found to influence this direction in the video condition. These results indicate that high levels of relevant motor expertise are required to beneficially employ visual and motor information of a co-performer for sensorimotor synchronization, which may qualify the effects of dPMC and IPS involvement
Raman spectroscopy of a single ion coupled to a high-finesse cavity
We describe an ion-based cavity-QED system in which the internal dynamics of
an atom is coupled to the modes of an optical cavity by vacuum-stimulated Raman
transitions. We observe Raman spectra for different excitation polarizations
and find quantitative agreement with theoretical simulations. Residual motion
of the ion introduces motional sidebands in the Raman spectrum and leads to ion
delocalization. The system offers prospects for cavity-assisted
resolved-sideband ground-state cooling and coherent manipulation of ions and
photons.Comment: 8 pages, 6 figure
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