Efeitos cardiorrespiratórios da tiletamina-zolazepam em cães hipovolêmicos

O objetivo deste estudo foi avaliar os efeitos da associação tiletamina-zolazepam em cães hipovolêmicos. Estudaram-se as alterações cardiovasculares em 14 cães, divididos em grupo A (controle, n=7) e grupo B (experimental, n=7). Os cães foram anestesiados com sevoflurano (1,5 concentração alveolar mínima - CAM) para a implantação dos cateteres venosos, arteriais e da termodiluição. A concentração do sevoflurano foi reduzida (0,5 CAM) e nos cães do grupo B, induziu-se hipovolemia retirando-se sangue na proporção de 30ml/kg de peso corpóreo. Subseqüentemente, registraram-se as freqüências cardíaca (FC) e respiratória (FR), a pressão arterial (PAM) e o débito cardíaco (DC), e aplicaram-se 10 mg/kg de tiletamina-zolazepam, pela via intravenosa. Aos cães do grupo A aplicou-se igual tratamento. Os cães foram observados por 120 minutos. A associação tiletamina-zolazepam produziu apnéia transitória e manteve estável a FC, PAM e DC. O resultados permitem concluir que a associação manteve estáveis as pressões arteriais sistólica, diastólica e média, e não alterou o débito cardíaco, podendo vir a ser usada com segurança na anestesia de cães com hipovolemia.

Somatoform and dissociative disorders

• The somatoform disorders are psychiatric illnesses that present as physical disorders. • The somatoform disorders are not to be confused with malingering, which is the intentional production of symptoms to avoid some responsibility or duty. • Somatisation is a method of expressing anxiety and distress and is found in all cultural groups. • The distress and suffering experienced by clients with a somatoform disorder are real, although the medical basis for their symptoms is not. • Clients with a somatoform disorder are most frequently encountered in primary health care settings. • The dissociative disorders are marked by an abrupt, temporary change in consciousness, cognition, memory, identity or behaviour.

An electron spectroscopic study of the adsorption of nitrogen on a Ni/TiO2 catalyst prepared in situ in the spectrometer: evidence for dissociative adsorption in the strong-metal-support-interaction (SMSI) state

Nitrogen is dissociatively adsorbed on an annealed Ni/TiO2 surface just as on a Ti–Ni alloy surface while it is molecularly adsorbed on a Ni/Al2O3 surface.

Case studies on the formation of chalcogenide self-assembled monolayers on surfaces and dissociative processes

This report examines the assembly of chalcogenide organic molecules on various surfaces, focusing on cases when chemisorption is accompanied by carbon-chalcogen atom-bond scission. In the case of alkane and benzyl chalcogenides, this induces formation of a chalcogenized interface layer. This process can occur during the initial stages of adsorption and then, after passivation of the surface, molecular adsorption can proceed. The characteristics of the chalcogenized interface layer can be significantly different from the metal layer and can affect various properties such as electron conduction. For chalcogenophenes, the carbon-chalcogen atombond breaking can lead to opening of the ring and adsorption of an alkene chalcogenide. Such a disruption of the pi-electron system affects charge transport along the chains. Awareness about these effects is of importance from the point of view of molecular electronics. We discuss some recent studies based on X-ray photoelectron spectroscopy that shed light on these aspects for a series of such organic molecules.

Kinetics of dissociative water adsorption on stepped Si(001), on Si(115), Si(113), Si(5,5,12) and Si(112)

We present photoelectron spectroscopic and low energy electron diffraction measurements of water adsorption on flat Si samples of the orientations (001), (115), (113), (5,5,12) and (112) as well as on curved samples covering continuously the ranges (001)-(117) and (113)-(5,5,12)-(112). On all orientations, water adsorption is dissociative (OH and H) and non-destructive. On Si(001) the sticking coefficient S and the saturation coverage Theta(sat) are largest. On Si(001) and for small miscuts in the [110]-azimuth, S is constant nearly up to saturation which proves that the kinetics involves a weakly bound mobile precursor state. For (001)-vicinals with high miscut angles (9-13 degrees), the step structure breaks down, the precursor mobility is affected and the adsorption kinetics changed. On (115), (113), (5,5,12) and (112), the values of S and Theta(sat) are smaller which indicates that not all sites are able to dissociate and bind water. For (113) the shape of the adsorption curves Theta versus exposure shows the existence of two adsorption processes, one with mobile precursor kinetics and one with Langmuir-like kinetics. On (5,5,12), two processes with mobile precursor kinetics are observed which are ascribed to adsorption on different surface regions within the large surface unit cell. From the corresponding values of S and Theta(sat), data for structure models are deduced. (C) 1997 Elsevier Science B.V.

Quantum-mechanical calculations of vibrationally resolved cross sections for non-dissociative charge transfer of O3+ with H-2

Charge transfer due to collisions of ground state O3+ (2s(2)2p P-2) ions with molecular hydrogen is investigated using the quantum-mechanical molecular-orbital close-coupling (MOCC) method, and electronic and vibrational state-selective cross sections along with the corresponding differential cross sections are calculated for projectile energies of 100, 500, 1000 and 5000 eV/u at the orientation angles of 25 degrees,45 degrees and 89 degrees. The adiabatic potentials and radial coupling matrix elements utilized in the QMOCC calculations were obtained with the spin-coupled valence-bond approach. The infinite order sudden approximation (IOSA) and the vibrational sudden approximation (VSA) are utilized to deal with the rotation of H-2 and the coupling between the electron and the vibration of H-2. It is found that the distribution of vibrationally resolved cross sections with the vibrational quantum number upsilon' of H-2(+) (upsilon') varies with the increment of the projectile energy; and the electronic and vibrational stateselective differential cross sections show similar behaviors: there is a highest platform within a very small scattering angle, beyond which the differential cross sections decrease as the scattering angle increases and lots of oscillating structures appear, where the scattering angle of the first structure decreases as E-P(-1/2) with the increment of the projectile energy E-P; and the structure and amplitude of the differential cross sections are sensitive to the orientation of molecule H-2, which provides a possibility to identify the orientations of molecule H-2 by the vibrational state-selective differential scattering processes.

利用HIRFL-CSR开展分子离子复合离解研究的可行性分析；Feasibility Analysis of Studying Dissociative Recombination Processes of Molecular Ions at HIRFL-CSR

介绍了储存环高精度分子谱学研究的科学意义、国内外研究现状和利用HIRFL-CSR开展该项研究的优势,着重论证了HIRFL-CSR分子离子注入实验环的总体设计方案和技术方案。通过在HIRFL-CSR实验环上增建一条分子离子注入线,将实验环改造成能兼顾现有物理实验和大分子物理研究的综合性研究平台,为分子离子复合离解研究提供良好的技术支撑。特别是质量数大于70的分子离子,能显著提高其能量分辨。

Dissociative recombination of the acetaldehyde cation, CH3CHO+

The dissociative recombination of the acetaldehyde cation, CH3CHO+, has been investigated at the heavy ion storage ring CRYRING at the Manne Siegbahn Laboratory in Stockholm, Sweden. The dependence of the absolute cross section of the reaction on the relative kinetic energy has been determined and a thermal rate coefficient of k(T) = (1.5 +/- 0.2) x 10(-6) (T/300)(-0.70 +/- 0.02) cm(3) s(-1) has been deduced, which is valid for electron temperatures between similar to 10 and 1000 K. The branching fractions of the reaction were studied at similar to 0 eV relative kinetic energy and we found that breaking one of the bonds between two of the heavy atoms occurs in 72 +/- 2% of the reactions. In the remaining events the three heavy atoms stay in the same product fragment. While the branching fractions are fairly similar to the results from an earlier investigation into the dissociative recombination of the fully deuterated acetaldehyde cation, CD3CDO+, the thermal rate coefficient is somewhat larger for CH3CHO+. Astrochemical implications of the results are discussed.

DISSOCIATIVE RECOMBINATION OF PROTONATED PROPIONITRILE, CH3CH2CNH+: IMPLICATIONS FOR TITAN'S UPPER ATMOSPHERE

The dissociative recombination of protonated propionitrile, CH3CH2CNH+, has been investigated at the heavy ion storage ring, CRYRING, at the Manne Siegbahn Laboratory, Stockholm University, Sweden. The thermal rate coefficient has been deduced to follow k(T) = (1.5 +/- 0.2) x 10(-6) (T/300)(-0.76) (+/-) (0.02) cm(3) s(-1) for electron temperatures ranging from similar to 10 to similar to 1000 K. Measurements of the branching fractions were performed at similar to 0 eV relative kinetic energy. It has been found that in 43% +/- 2% of the reactions the four heavy atoms remain in the same product fragment. An equal portion of the reactions leads to products where one of the heavy atoms is split off from the other three and 14% +/- 1% result in a breakup into two heavy fragments containing two heavy atoms each. We discuss the significance of the data to Titan's upper atmosphere.

Experimental studies of the dissociative recombination of CD3CDOD+ and CH3CH2OH2+

Aims. We determine branching fractions, cross sections and thermal rate constants for the dissociative recombination of CD3CDOD+ and CH3CH2OH2+ at the low relative kinetic energies encountered in the interstellar medium. Methods. The experiments were carried out by merging an ion and electron beam at the heavy ion storage ring CRYRING, Stockholm, Sweden. Results. Break-up of the CCO structure into three heavy fragments is not found for either of the ions. Instead the CCO structure is retained in 23 +/- 3% of the DR reactions of CD3CDOD+ and 7 +/- 3% in the DR of CH3CH2OH2+, whereas rupture into two heavy fragments occurs in 77 +/- 3% and 93 +/- 3% of the DR events of the respective ions. The measured cross sections were fitted between 1-200 meV yielding the following thermal rate constants and cross-section dependencies on the relative kinetic energy: sigma(E-cm[eV]) = 1.7 +/- 0.3 x 10(-15)(Ecm[eV])(-1.23 +/- 0.02) cm(2) and k(T) = 1.9 +/- 0.4 x 10(-6)(T/300)-0.73 +/- 0.02 cm(3) s(-1) for CH3CH2OH2+ as well as k(T) = 1.1 +/- 0.4 x 10(-6)(T/300)(-0.74 +/- 0.05) cm(3) s(-1) and s(Ecm[eV]) = 9.2 +/- 4 x 10(-16)(Ecm[eV])-1.24 +/- 0.05 cm(2) for CD3CDOD+

Femtosecond pump-probe mass spectra on the dissociative photoionization of CF3I

The multi-photon dissociative photoionization dynamics of CF3I has been studied with femtosecond two-color pump-probe time-of-flight mass spectra at a pump pulse of 265 nm and a probe pulse of 398 nn. This enables the A band and 5ppi(3)7ssigma((2)Pi(1/2)) Rydberg state to be accessed with the pump beam. The observed fast and slow decay components of CF3+ and I+ reflect the fast repulsive A band and some higher lying ion-pair states may be responsible for the decay of the 5ppi(3)7ssigma((2)Pi(1/2)) Rydberg state. The results provide information on the different multi-photon pathways producing these ions and the de-excitation mechanism of the 5ppi(3)7ssigma((2)Pi(1/2)) Rydberg state. (C) 2003 Elsevier Science B.V. All rights reserved.

ENHANCED AMPEROMETRIC DETECTOR FOR LOCAL-ANESTHETICS IN LIQUID-CHROMATOGRAPHY WITH METAL-OXIDE DISPERSED GLASSY-CARBON ELECTRODES

Chemically modified electrodes (CMEs) prepared by the dispersion of metal oxide particles on a glassy carbon (GC) substrate greatly enhance the voltammetric response and amperometric detection of local anesthetics following liquid chromatography (LC). The enhancement is more pronounced with the GC electrodes dispersed by the metal oxides of higher oxidation states (+3, +4) and for the species exhibiting relatively slow electrode kinetics under given conditions. With an applied potential of 1.2 V (vs. SCE), LC amperometric detection of the analytes at the alpha-alumina modified GC surface gives detection limits 2-5 times lower than those obtained at the bare electrode. The metal oxide-dispersed electrodes display significant improvement in sensitivity, and selectivity and indicate excellent preparation reproducibility and performance stability.