122 research outputs found
Suivi des enfants après une anesthésie pour une intervention ambulatoire: incidence des effets indésirables
Introduction : Les effets indésirables de l'anesthésie ont déjà été étudiés par de nombreuses équipes qui ont recherché leurs incidences, leurs facteurs de risque, leurs moyens de prévention ainsi que leurs traitements. Le but de cette étude est d'évaluer l'incidence des effets indésirables d'une anesthésie générale spécifiquement chez l'enfant après une intervention en ambulatoire. Elle permet aussi de savoir si l'incidence des nausées et vomissements tardifs est influencée par le fait de donner rapidement une boisson ou une collation au réveil de l'anesthésie.
Méthodologie : Etude prospective avec une récolte de données sur cinq mois concernant des enfants âgés de 0 à 16 ans. Les données ont été obtenues à l'aide des rapports d'anesthésie ainsi qu'un téléphone aux parents au troisième jour post-opératoire.
Résultats: Cent patients ont répondu aux critères. L'incidence des nausées et vomissements précoces est de 14.3%, des vomissements tardifs de 10% et des nausées tardives de 5%. De plus, 46% des patients présentaient des douleurs, 41% des troubles du sommeil, 28.6% des modifications des selles et 22% des troubles de l'appétit.
Conclusion : Donner rapidement aux enfants une boisson ou une collation au réveil de l'anesthésie n'entraîne pas de différence significative sur l'incidence des nausées et vomissements tardifs
Torque magnetometry on single-crystal high temperature superconductors near the critical temperature: a scaling approach
Angular-dependent magnetic torque measurements performed near the critical
temperature on single crystals of HgBa_{2}CuO_{4+y}, La_{2-x}Sr{x}CuO_{4}, and
YBa_{2}Cu_{3}O_{6.93} are scaled, following the 3D XY model, in order to
determine the scaling function dG^{\pm}(z)/dz which describes the universal
critical properties near T_{c}. A systematic shift of the scaling function with
increasing effective mass anisotropy \gamma = (m_{ab}*/m_{c}*)^{1/2} is
observed, which may be understood in terms of a 3D-2D crossover. Further
evidence for a 3D-2D crossover is found from temperature-dependent torque
measurements carried out in different magnetic fields at different field
orientations \delta, which show a quasi 2D "crossing region'' (M*,T*). The
occurrence of this "crossing phenomenon'' is explained in a phenomenological
way from the weak z dependence of the scaling function around a value z = z*.
The "crossing'' temperature T* is found to be angular-dependent. Torque
measurements above T_{c} reveal that fluctuations are strongly enhanced in the
underdoped regime where the anisotropy is large, whereas they are less
important in the overdoped regime.Comment: 9 pages, 10 figures, submitted to PR
Oxygen isotope effect on the in-plane penetration depth in underdoped La_{2-x}Sr_{x}CuO_{4} single crystals
We report measurements of the oxygen isotope effect (OIE) on the in-plane
penetration depth \lambda_{ab}(0) in underdoped La_{2-x}Sr_{x}CuO_{4} single
crystals. A highly sensitive magnetic torque sensor with a resolution of \Delta
\tau ~ 10^{-12} Nm was used for the magnetic measurements on microcrystals with
a mass of ~ 10 microg. The OIE on \lambda_{ab}^{-2}(0) is found to be -10(2)%
for x = 0.080 and -8(1)% for x = 0.086. It arises mainly from the oxygen mass
dependence of the in-plane effective mass m_{ab}*. The present results suggest
that lattice vibrations are important for the occurrence of high temperature
superconductivity.Comment: 4 pages, 3 figures, submitted to PR
Drain Versus No Drain in Open Mesh Repair for Incisional Hernia, Results of a Prospective Randomized Controlled Trial.
Open mesh repair of incisional hernia is associated with different local complications, particularly bleeding and seroma formation. Traditionally, drains have been placed perioperatively to prevent these complications, despite the lack of scientific evidence or expert consensus. We formulated the hypothesis that the absence of drainage would reduce number of patients presenting collections or complications. The present study aimed to compare postoperative complication rates after open mesh repair for incisional hernia with or without prophylactic wound drainage.
Prospective randomized study using standardized surgical technique and drain placement. The primary endpoint was the evaluation of residual fluid collection with ultrasound on postoperative day 30. Other complications, subdivided into medical and surgical, were analyzed as secondary endpoints.
There were 144 patients randomized (70 with drain, 74 without drain). No difference was identified between both groups for fluid collection at 30 days (60.3% vs. 62%, p = 0.844). However, less surgical complications were identified in the drain group (21.7% vs. 42.7%, p = 0.007), with a lower wound dehiscence rate (1.5% vs. 9.3%, p = 0.041).
Prophylactic drainage in open incisional hernia repair does not objectively reduce the rate of postoperative fluid collections. Therefore, our results do not support the use of routine drainage in incisional hernia repair.
Trial registration on clinicaltrials.gov (NCT00478348)
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
Josephson junction between anisotropic superconductors
The sin-Gordon equation for Josephson junctions with arbitrary misaligned
anisotropic banks is derived. As an application, the problem of Josephson
vortices at twin planes of a YBCO-like material is considered. It is shown that
for an arbitrary orientation of these vortices relative to the crystal axes of
the banks, the junctions should experience a mechanical torque which is
evaluated. This torque and its angular dependence may, in principle, be
measured in small fields, since the flux penetration into twinned crystals
begins with nucleation of Josephson vortices at twin planes.Comment: 6 page
Synthesis and Bulk Properties of Oxychloride Superconductor Ca2-xNaxCuO2Cl2
Polycrystalline samples and submillimeter size single crystals of Na-doped
Ca2CuO2Cl2 have been synthesized under high pressure. A series of experiments
showed that the Na content depends not only on the pressure during the
synthesis but also on the synthesis temperature and time. From a comparison of
the Na-CCOC data with those of structurally related La214 cuprate
superconductors we concluded that chlorine at the apical site is less effective
that oxygen in supplying charge carriers to the CuO2 plans. As a result, the
coupling between the CuO2 planes is weakened, the transition temperature Tc is
reduced and the anisotropic nature is enhanced.Comment: 7 pages, 7 figures, 1 table, presenthed at the Eucas 2007 conference.
Accepted for "Journal of Physics: Conference Series (JPCS)" 2008 and European
News Forum, Issue 3 (2008
Dynamical Induction of s-wave Component in d-wave Superconductor Driven by Thermal Fluctuations
We investigated the mutual induction effects between the d-wave and the
s-wave components of order parameters due to superconducting fluctuation above
the critical temperatures and calculated its contributions to paraconductivity
and excess Hall conductivity based on the two-component stochastic TDGL
equation. It is shown that the coupling of two components increases
paraconductivity while it decreases excess Hall conductivity compared to the
cases when each component fluctuates independently. We also found the singular
behavior in the paraconductivity and the excess Hall conductivity dependence on
the coupling parameter which is consistent with the natural restriction among
the coefficients of gradient terms.Comment: 10 pages, 4 figures included, submitted to J.Phys.Soc.Jp
Raman study of carrier-overdoping effects on the gap in high-Tc superconducting cuprates
Raman scattering in the heavily overdoped (Y,Ca)Ba_2Cu_3O_{7-d} (T_c = 65 K)
and Bi_2Sr_2CaCu_2O_{8+d} (T_c = 55 K) crystals has been investigated. For the
both crystals, the electronic pair-breaking peaks in the A_{1g} and B_{1g}
polarizations were largely shifted to the low energies close to a half of
2Delta_0, Delta_0 being the maximum gap. It strongly suggests s-wave mixing
into the d-wave superconducting order parameter and the consequent
manifestation of the Coulomb screening effect in the B_{1g}-channel. Gradual
mixing of s-wave component with overdoping is not due to the change of crystal
structure symmetry but a generic feature in all high-T_c superconducting
cuprates.Comment: 5 pages, 4 figures, to be published in Phys. Rev. B, Rapid
communicaito
Spatial Symmetry of Superconducting Gap in YBa2Cu3O7-\delta Obtained from Femtosecond Spectroscopy
The polarized femtosecond spectroscopies obtained from well characterized
(100) and (110) YBa2Cu3O7-\delta thin films are reported. This bulk-sensitive
spectroscopy, combining with the well-textured samples, serves as an effective
probe to quasiparticle relaxation dynamics in different crystalline
orientations. The significant anisotropy in both the magnitude of the
photoinduced transient reflectivity change and the characteristic relaxation
time indicates that the nature of the relaxation channel is intrinsically
different in various axes and planes. By the orientation-dependent analysis,
d-wave symmetry of the bulk-superconducting gap in cuprate superconductors
emerges naturally.Comment: 8 pages, 4 figures. To be published in Physical Review B, Rapid
Communication
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