Changing inter-molecular spin-orbital coupling for generating magnetic field effects in phosphorescent organic semiconductors

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Schwarzschild generalized black hole horizon and the embedding space

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

The effects of intrathecal administration of betamethasone over the dogs' spinal cord and meninges

OBJETIVO: Determinar possíveis alterações clínicas e histológicas determinadas pela administração da betametasona no espaço subaracnóideo de cães. MÉTODOS: Vinte e um cães foram incluídos no estudo de forma aleatória e encoberta. Depois de anestesiados, os cães foram submetidos a punção subaracóidea com injeção de 1 ml da solução sorteada. Os animais receberam solução salina 0,9% em G1, betametasona na dose de 1,75 mg em G2 e betametasona na dose de 3,5 mg em G3. Todos os animais foram mantidos em observação clínica por 21 dias, sendo posteriormente sacrificados. Porções da medula espinhal e sacral foram removidas para análise histológica por microscopia óptica. RESULTADOS: Não foram detectadas alterações clínicas em quaisquer dos animais incluídos no estudo. da mesma forma, nenhum animal do G1 apresentou alterações histológicas. Infiltração inflamatória foi observada em dois cães, um do G2 e outro e G3. No cão do G2 onde a infiltração inflamatória foi observada ocorreu, conjuntamente, hemorragia e necrose. em dois cães, um de G2 e outro de G3, observou-se discreta fibrose e espessamento da aracnóide, sendo focal em um e difusa no outro. CONCLUSÃO: A administração subaracnóidea de betametasona determinou alterações histológicas em medula e meninges de alguns dos cães envolvidos no estudo.

The Effects of Subarachnoid Administration of Preservative-Free S(+)-Ketamine on Spinal Cord and Meninges in Dogs

BACKGROUND: The N-methyl-D-aspartate receptor antagonist ketamine and its active enantiomer, S(+)-ketamine, have been injected in the epidural and subarachnoid spaces to treat acute postoperative pain and relieve neuropathic pain syndrome. In this study we evaluated the effects of a single dose of preservative-free S(+)-ketamine, in doses usually used in clinical practice, in the spinal cord and meninges of dogs.METHODS: Under anesthesia (IV etomidate (2 mg/kg) and fentanyl (0.005 mg/kg), 16 dogs (6 to 15 kg) were randomized to receive a lumbar intrathecal injection (L5/6) of saline solution of 0.9% (control group) or S(+)-ketamine 1 mg/kg(-1) (ketamine group). All doses were administered in a volume of 1 mL over a 10-second interval. Accordingly, injection solution ranged from 0.6% to 1.5%. After 21 days of clinical observation, the animals were killed; spinal cord, cauda equine root, and meninges were removed for histological examination with light microscopy. Tissues were examined for demyelination (Masson trichrome), neuronal death (hematoxylin and eosin) and astrocyte activation (glial fibrillary acidic protein).RESULTS: No clinical or histological alterations of spinal tissue or meninges were found in animals from either control or ketamine groups.CONCLUSION: A single intrathecal injection of preservative-free S(+)-ketamine, at 1 mg/kg-1 dosage, over a concentration range of 6 to 15 mg/mL injected in the subarachnoid space in a single puncture, did not produce histological alterations in this experimental model. (Anesth Analg 2012;114:450-55)

Effects on mother and fetus of epidural and combined spinal-epidural techniques for labor analgesia

OBJETIVO: A peridural (AP) e a técnica de duplo bloqueio (DB) são utilizadas em analgesia para o trabalho de parto. Este estudo comparou os efeitos na mãe e no feto de ambas as técnicas em analgesia e anestesia para o parto. MÉTODOS: Quarenta parturientes ASA I e II receberam por via peridural 15 ml de ropivacaína a 0,125% (grupo AP) e 5 µg de sufentanil com 2,5 mg bupivacaína por via subaracnóidea (grupo DB). Foram avaliados: intensidade de dor, altura do bloqueio sensitivo, tempo de latência, bloqueio motor, duração da analgesia de parto, tempo para a resolução do parto, hipotensão materna e presença de prurido. Os recém-nascidos foram avaliados pelo índice de Apgar e escore da capacidade adaptativa e neurológica (ECAN), método de Amiel-Tison. RESULTADOS: Não houve diferenças significativas entre os grupos na intensidade da dor, no tempo de latência, no nível do bloqueio sensitivo e no índice de Apgar. O bloqueio motor, a duração da analgesia e o tempo para resolução do parto foram maiores no grupo DB, do qual sete parturientes apresentaram prurido leve. ECAN foi maior no grupo AP após meia hora, duas horas e 24 horas. Noventa e cinco por cento dos recém-nascidos do grupo AP e 60% do grupo DB foram considerados neurologicamente vigorosos ao exame de 24 horas. CONCLUSÃO: As duas técnicas mostraram-se eficazes para analgesia do trabalho de parto. As parturientes do grupo DB apresentaram prurido e trabalho de parto mais prolongado. Recém-nascidos de mães que receberam analgesia de parto via peridural apresentaram melhor ECAN.

Clinical and Histological Effects of the Intrathecal Administration of Methylprednisolone in Dogs

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Cardiopulmonary and analgesic effects of caudal epidurally administered ropivacaine in cattle

Objective To assess cardiopulmonary and analgesic effects after administration of ropivacaine into the caudal epidural space of cattle.Study design Prospective, single-dose trial.Animals Eight healthy mixed breed cows aged 8 +/- 5 years and weighing 507 +/- 112 kg.Methods Caudal epidural anesthesia was produced in cows with 0.75% ropivacaine (0.11 mg kg(-1)). Onset time, duration and cranial spread of analgesia were recorded. Heart rate (HR), respiratory rate (f(R)), rectal temperature (RT), and mean arterial blood pressure (MAP) were measured prior to epidural administration (T-0) and at 15, 30, 60, 120, 180 and 240 minutes after epidural administration (T-15, T-30, T-60, T-120, T-180 and T-240). Arterial blood acid-base balance (pH, standard bicarbonate and base excess), gas tension (PaO2, PaCO2, SaO(2)) and electrolytes (Na+, K+, iCa(2+), Cl-) were recorded at T-0, T-30, T-60, T-120, T-180 and T-240. Ataxia was evaluated at T-0, T-30, T-60, T-120, T-180 and T-240 and at 1 hour intervals thereafter until analgesia was no longer present in each animal.Results Epidurally administered ropivacaine induced variable analgesia extending bilaterally from the coccyx to S3. Time to onset of analgesia and mean duration in the perineal area were 15 +/- 4 and 359 +/- 90 minutes, respectively. Respiratory rate and RT increased from T-120 to T-240 when compared to the value at T-0. Ionized calcium and chloride concentrations increased at T-180 and T-240 when compared to T-0. The other variables were not significantly different from baseline values (p > 0.05). Four animals were mildly ataxic.Conclusion and clinical relevance Ropivacaine (0.75%, 0.11 mg kg(-1)) can be administered by caudal epidural injection to produce prolonged bilateral perineal analgesia with minimal ataxia and cardiopulmonary changes in standing cattle.

Interfacial surface charge and free accessibility to the PLA(2)-active site-like region are essential requirements for the activity of Lys49 PLA(2) homologues

Lys49 phospholipase A(2) homologues are highly myotoxic and cause extensive tissue damage but do not display hydrolytic activity towards natural phospholipids. The binding of heparin, heparin derivatives and polyanionic compounds such as suramin result in partial inhibition (up to 60%) of the myotoxic effects due to a change in the overall charge of the interfacial surface. In vivo experiments demonstrate that polyethylene glycol inhibits more than 90% of the myotoxic effects without exhibiting secondary toxic effects. The crystal structure of bothropstoxin-I complexed with polyethylene glycol reveals that this inhibition is due to steric hindrance of the access to the PLA(2)-active site-like region. These two inhibitory pathways indicate the roles of the overall surface charge and free accessibility to the PLA2-active site-like region in the functioning of Lys49 phospholipases A(2) homologues. Molecular dynamics simulations, small angle X-ray scattering and structural analysis indicate that the oligomeric states both in solution and in the crystalline states of Lys49 phospholipases A2 are principally mediated by hydrophobic contacts formed between the interfacial surfaces. These results provide the framework for the potential application of both clinically approved drugs for the treatment of Viperidae snakebites. (c) 2006 Elsevier Ltd. All rights reserved.

The Origin of Nonmonotonic Complex Behavior and the Effects of Nonnative Interactions on the Diffusive Properties of Protein Folding

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

CP trajectory diagram - a tool for a pictorial representation of CP and matter effects in neutrino oscillations

We introduce a CP trajectory diagram in bi-probability space as a powerful tool for a pictorial representation of the genuine CP and the matter effects in neutrino oscillations. The existence of correlated ambiguity in the B is uncovered. The principles of tuning the beam energy for a determination of CP-violating phase delta and the sign of Deltam(13)(2) given baseline distance are proposed to resolve the ambiguity and to maximize the CP-odd effect. We finally point out, quite contrary to what is usually believed, that the ambiguity may be resolved with similar to 50% chance in the super-JHF experiment despite its relatively short baseline of 300 km. (C) 2003 Elsevier B.V. B.V. All rights reserved.

A model for Hopfions on the space-time S(3)xR

We construct static and time dependent exact soliton solutions for a theory of scalar fields taking values on a wide class of two dimensional target spaces, and defined on the four dimensional space-time S-3 X R. The construction is based on an ansatz built out of special coordinates on S3. The requirement for finite energy introduce boundary conditions that determine an infinite discrete spectrum of frequencies for the oscillating solutions. For the case where the target space is the sphere S-2, we obtain static soliton solutions with nontrivial Hopf topological charges. In addition, such Hopfions can oscillate in time, preserving their topological Hopf charge, with any of the frequencies belonging to that infinite discrete spectrum. (C) 2005 American Institute of Physics.

Low-energy three-body charge transfer reactions with Coulomb interaction in the final state

Three-body charge transfer reactions with Coulomb interaction in the final state are considered within the framework of coordinate-space integro-differential Faddeev-Hahn-type equations within two- and six-state close-coupling approximations. The method is employed to study direct muon transfer in low-energy collisions of the muonic hydrogen H-mu by helium (He2+) and lithium (Li3+) nuclei. The experimentally observed isotopic dependence is reproduced.

Swimming versus swinging effects in spacetime

Wisdom has recently unveiled a new relativistic effect, called spacetime swimming, where quasirigid free bodies in curved spacetimes can speed up, slow down or deviate their falls by performing local cyclic shape deformations. We show here that for fast enough cycles this effect dominates over a nonrelativistic related one, named here space swinging, where the fall is altered through nonlocal cyclic deformations in Newtonian gravitational fields. We expect, therefore, to clarify the distinction between both effects leaving no room to controversy. Moreover, the leading contribution to the swimming effect predicted by Wisdom is enriched with a higher order term and the whole result is generalized to be applicable in cases where the tripod is in large redshift regions.

Lorentz-violating dilatations in momentum space and some extensions on nonlinear actions of Lorentz-algebra-preserving systems

We work on some general extensions of the formalism for theories which preserve the relativity of inertial frames with a nonlinear action of the Lorentz transformations on momentum space. Relativistic particle models invariant under the corresponding deformed symmetries are presented with particular emphasis on deformed dilatation transformations. The algebraic transformations relating the deformed symmetries with the usual (undeformed) ones are provided in order to preserve the Lorentz algebra. Two distinct cases are considered: a deformed dilatation transformation with a spacelike preferred direction and a very special relativity embedding with a lightlike preferred direction. In both analysis we consider the possibility of introducing quantum deformations of the corresponding symmetries such that the spacetime coordinates can be reconstructed and the particular form of the real space-momentum commutator remains covariant. Eventually feasible experiments, for which the nonlinear Lorentz dilatation effects here pointed out may be detectable, are suggested.

Effects of time-periodic linear coupling on two-component Bose-Einstein condensates in two dimensions

We examine two-component Gross-Pitaevskii equations with nonlinear and linear couplings, assuming self-attraction in one species and self-repulsion in the other, while the nonlinear inter-species coupling is also repulsive. For initial states with the condensate placed in the self-attractive component, a sufficiently strong linear coupling switches the collapse into decay (in the free space). Setting the linear-coupling coefficient to be time-periodic (alternating between positive and negative values, with zero mean value) can make localized states quasi-stable for the parameter ranges considered herein, but they slowly decay. The 2D states can then be completely stabilized by a weak trapping potential. In the case of the high-frequency modulation of the coupling constant, averaged equations are derived, which demonstrate good agreement with numerical solutions of the full equations. (C) 2007 Elsevier B.V. All rights reserved.