RESUMO
We report on experimental synthesis and theoretical studies of ultrasharp BN-nanocones. Using scanning and transmission electron microscopy, the cone-like morphology of synthesized products was confirmed. Theoretical analysis of the dipole moment nature in h-BN nanocones reveals that the moment has contributions from the polarity of B-N bonds and electronic flexoelectric effect associated with a curved h-BN lattice. The latter phenomenon is predicted on the basis of the extension of the theory of flexoelectric effects in the h-BN lattice through establishing universality of the linear dependence of flexoelectric dipole moments on local curvature in various nano- h-BN networks (nanotubes and fullerenes). Our study of the atomic structure response and its polarization under deformation of nanocones with different apex angles shows the advantageous properties of cones with the smallest angles.
RESUMO
A total of 74 patients with suspected discal hernia were studied. To clarify its diagnosis, epidural scintigraphy along with routine studies was used. The established diagnosis was verified during surgery. Carbonic acid laser was applied to 22 patients in addition to the conventional procedures.
Assuntos
Deslocamento do Disco Intervertebral/complicações , Vértebras Lombares , Plexo Lombossacral , Radiculopatia/etiologia , Sacro , Espaço Epidural , Feminino , Humanos , Deslocamento do Disco Intervertebral/diagnóstico por imagem , Deslocamento do Disco Intervertebral/cirurgia , Terapia a Laser , Vértebras Lombares/diagnóstico por imagem , Vértebras Lombares/cirurgia , Plexo Lombossacral/diagnóstico por imagem , Masculino , Pessoa de Meia-Idade , Radiculopatia/diagnóstico por imagem , Cintilografia , Sacro/diagnóstico por imagem , Sacro/cirurgia , Pertecnetato Tc 99m de SódioRESUMO
A prolonged blockade of the brachial plexus by a subclavicular approach was performed in a 22-year-old patient with combined trauma and severe pain in the left arm. The administration of 20 ml of a 0.3% dicaine solution through a catheter led to spinal anesthesia accompanied by the development of transient hemodynamic and respiration disturbances, which were arrested without medication or controlled lung ventilation. A possible reason for this complication is traumatic plexitis. When performing a blockade of the brachial plexus one should administer a test dose of an anesthetic prior to the entire drug dosage.
Assuntos
Traumatismos do Braço/complicações , Plexo Braquial , Bloqueio Nervoso/efeitos adversos , Dor/etiologia , Tetracaína/efeitos adversos , Adulto , Humanos , MasculinoRESUMO
Epidural analgesia (EA) with dicaine and morphine has been compared in 34 patients with pain syndrome caused by degenerative dystrophy of lumbar vertebrae. The advantages of EA with dicaine have been observed. 35.3% of patients have been subject to surgery. In the rest of patients pain syndrome was relieved. Radionuclide epidurography has shown that the volume of the anesthetic solution injected should not exceed 10 ml.
Assuntos
Analgesia Epidural , Vértebras Lombares , Osteoartrite/complicações , Dor/etiologia , Tetracaína , Adulto , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Dor/prevenção & controleAssuntos
Acetanilidas , Bloqueio Nervoso , Dor Pós-Operatória/prevenção & controle , Procaína , Cirurgia Torácica , Trimecaína , Adulto , Idoso , Feminino , Humanos , Masculino , Pessoa de Meia-IdadeAssuntos
Anestesia Epidural , Hemodinâmica/efeitos dos fármacos , Dor/tratamento farmacológico , Troca Gasosa Pulmonar/efeitos dos fármacos , Fraturas das Costelas/terapia , Adolescente , Adulto , Idoso , Ensaios Clínicos como Assunto , Humanos , Pessoa de Meia-Idade , Morfina/administração & dosagem , Dor/fisiopatologia , Fraturas das Costelas/fisiopatologia , Tetracaína/administração & dosagemRESUMO
Anisotropic penetration of magnetic flux in MgB(2) films grown on vicinal sapphire substrates is investigated using magneto-optical imaging. Regular penetration above 10 K proceeds more easily along the substrate surface steps, the anisotropy of the critical current being 6%. At lower temperatures the penetration occurs via abrupt dendritic avalanches that preferentially propagate perpendicular to the surface steps. This inverse anisotropy in the penetration pattern becomes dramatic very close to 10 K where all flux avalanches propagate in the strongest pinning direction. The observed behavior is fully explained using a thermomagnetic model of the dendritic instability.
RESUMO
The literature data has been analysed to evaluate the efficacy of the methods of regional analgesia (RA) in closed chest trauma. Various types of blocks are described. Epidural analgesia with local anaesthetics and narcotics is detailed. Epidural electrostimulation and introduction of drugs affecting the endogenous systems are shown to show good promises.