Studies on the encapsulation of diclofenac in small unilamellar liposomes of soya phosphatidylcholine

The encapsulation of acid (AD) and sodium diclofenac (SD) in small unilamellar liposomes (SUV) as well as the interactions of the drug with the bilayer was studied. SUV was prepared by sonication from multilamellar liposomes containing soya phosphatidylcholine and diclofenac at various proportions. The size distribution obtained from dynamic light scattering showed that the incorporation of SD decreases significantly the size of the liposomes suggesting that the drug interacts with the bilayer of the liposomes. This size decrease is related with the phase transition of liposomes to mixed micelar solution. The encapsulation of the hydrophilic dye indocyanine green in the aqueous compartment of liposomes showed that the rate of captured dye decreases with SD concentration suggesting the transition of liposomes to mixed micelles. The P-31 NMR analysis indicates that SD interacts with the phosphate of phosphatidylcholine head groups. A schematic model for interaction of SD with phosphatidylcholine of the liposomes in which the diclofenac anion interacts with the ammonium group of the phospholipid and the dichloropheryl ring occupies a more internal site of bilayer near phosphate group was proposed. (C) 2004 Elsevier B.V. All rights reserved.

Matemal separation affects cocaine-induced locomotion and response to novelty in adolescent, but not in adult rats

Maternal separation is known to exert long-term effects on both behavior and the neuroendocrine system. We investigated cocaine-induced locomotor activation as well as the locomotor and corticosterone response to forced novelty in maternally separated adolescent and adult rats. Maternal separation consisted of separating litters from their darns daily during 5 h from postnatal days 2 to 6. Control animals were subjected only to regular cage changes. Cocaine- (10 mg/kg, i.p.) and novelty-induced locomotion were recorded in an activity cage. After the animals were tested for behavioral response to novelty, trunk blood samples were collected and plasma corticosterone levels were determined by radioimmunoassay. Adolescent rats exposed to maternal separation exhibited an increased locomotor response to novelty and cocaine; corticosterone levels were lower in these adolescent animals, after exposure to the novel environment. These effects of materrial separation were not observed in rats that were tested as adults. Thus the maternal separation protocol produced enduring but transient changes in the behavioral response to cocaine and in the stress response to novelty. (C) 2004 Elsevier B.V. All rights reserved.

PLGA nanoparticles containing praziquantel: effect of formulation variables on size distribution

Praziquantel has been shown to be highly effective against all known species of Schistosoma infecting humans. Spherical nanoparticulate drug carriers made of poly(D,L-lactide-co-glycolide) acid with controlled size were designed. Praziquantel, a hydrophobic molecule, was entrapped into the nanoparticles with theoretical loading varying from 10 to 30% (w/w). This investigates the effects of some process variables on the size distribution of nanoparticles prepared by emulsion-solvent evaporation method. The results show that sonication time, PLGA and drug amounts, PVA concentration, ratio between aqueous and organic phases, and the method of solvent evaporation have a significant influence on size distribution of the nanoparticles. (C) 2004 Elsevier B.V. All rights reserved.

Influence of Yersinia pseudotuberculosis outer proteins (Yops) on interleukin-12, tumor necrosis factor alpha and nitric oxide production by peritoneal macrophages

An essential key to pathogenicity in Yersinia is the presence of a 70 kb plasmid (pYV) which encodes a type-III secretion system and several virulence outer proteins whose main function is to enable the bacteria to survive in the host. Thus, a specific immune response is needed in which cytokines are engaged. The aim of this study was to assess the influence of Yersinia outer proteins (Yops) released by Yersinia pseudotuberculosis on the production of the proinflammatory cytokines, interleukin-12 (IL-12), and tumor necrosis factor alpha (TNF-alpha), and nitric oxide (NO) by murine peritoneal macrophages. To this end, female Swiss mice were infected intravenously with wild-type Y pseudotuberculosis or with mutant strains unable to secrete specific Yops (YopE, YopH, YopJ, YopM, and YpkA). on the 7th, 14th, 21st, and 28th days after infection, the animals were sacrificed and the cytokines and NO were assayed in the peritoneal macrophages culture supernatants. A fall in NO production was observed during the course of infection with all the strains tested, though during the infection with the strains that did not secrete YopE and YopH, the suppression occurred later. There was, in general, an unchanged or sometimes increased production of TNF-alpha between the 7th and the 21st day after infection, compared to the control group, followed by an abrupt decrease on the last day of infection. The IL-12 production was also suppressed during the infection, with most of the strains tested, except with those that did not secrete YopJ and YopE. The results suggest that Yops may suppress IL-12, TNF-alpha, and NO production and that the most important proteins involved in this suppression are YopE and YopH. (C) 2004 Elsevier B.V. All rights reserved.

Study of the diclofenac/phospholipid interactions with liposomes and monolayers

The interaction of diclofenae sodium (SD) with soya phosphatidylcholine (SPC) has been studied with floating Langmuir monolayers and liposomes. SD was either introduced into the subphase of SPC monolayers or co-spread with SPC on an aqueous subphase. In both cases, SD caused the surface pressure isotherm to become more expanded, thus demonstrating the affinity between SD and SPC. The incorporation of SD caused SPC liposomes to have a decreased diameter according to light scattering experiments. When SPC liposomes were injected into an aqueous subphase, their destruction yielding surface-active monomers could be monitored by changes in surface pressure. SD-loaded liposomes displayed a much faster kinetics when the surface density of surface-active monomers was plotted against time, with rate constants increasing significantly with the SD concentration. The kinetic profile can be quantitatively analyzed by plotting In[1 - (Gamma/Gamma(infinity))] versus t(1/2) (C) 2004 Elsevier B.V. All rights reserved.

Fruit of the jambolan tree (Eugenia jambolana Lam.) and experimental diabetes

The fruit of Indian Eugenia jambolana have been shown to have therapeutic properties, but because the therapeutic potential of a plant is related to the geographic region in which the plant was grown and to the part of the plant used, we investigated Brazilian Eugenia jambolana fruit using the same preparation and experimental methods as have been used in India. The well-established metabolic cage model was used to evaluate the physiological and metabolic parameters associated with streptozotocin-induced diabetes in rats (n = 10) which had been administered, by gavage, 50 mg per day of lyophilised Eugenia jambolana fruit-pulp extract for 41 days. We found that, compared to untreated controls, rats treated with the lyophilised fruit-pulp showed no observable difference in body weight, food or water intake, urine volume, glycaemia, urinary urea and glucose, hepatic glycogen, or on serum levels of total cholesterol, HDL cholesterol or triglycerides. No change was observed in the masses of epididymal or retroperitoneal adipose tissue or of soleus or extensor digitorum longus muscles. This lack of any apparent effect on the diabetes may be attributable to the regional ecosystem where the fruit was collected and/or to the severity of the induced diabetes. (C) 2004 Elsevier B.V.. All rights reserved.

Supercritical fluid extraction for pesticide multiresidue analysis in honey: determination by gas chromatography with electron-capture and mass spectrometry detection

An analytical procedure using supercritical fluid extraction (SFE) and capillary gas chromatography with electron-capture detection was developed to determine simultaneously residues of different pesticides (organochlorine, organophosphorus, organonitrogen and pyrethroid) in honey samples. Fortification experiments were conducted to test conventional extraction (liquid-liquid) and optimize the extraction procedure in SFE by varying the CO2-modifier, temperature, extraction time and pressure. Best efficiency was achieved at 400 bar using acetonitrile as modifier at 90 degreesC. For the clean-up step, Florisil cartridges were used for both methods LLE and SFE. Recoveries for majority of pesticides from fortified samples of honey at fortification level of 0.01-0.10 mg/kg ranged 75-94% from both methods. Limits of detection found were less than 0.01 mg/kg for ECD and confirmation of pesticide identity was performed by gas chromatography-mass spectrometry in selected-ion monitoring mode. The multiresidue methods in real honey samples were applied and the results of developed methods were compared. (C) 2004 Elsevier B.V. All rights reserved.

Anelastic spectroscopy in SmBa2Cu3O7

The possibility of variable stoichiometry and the high mobility of oxygen in the CuOx planes of SmBa2Cu3O7 give rise to a rich phase diagram. Measurements of the elastic energy loss and modulus (anelastic spectroscopy) as a function of temperature can distinguish among the different atomic jumps, which occur in the various phases or at different local ordering. In this paper, it is reported anelastic relaxation measurements in SmBa2Cu3O7, above room temperature, using a torsion pendulum operating in frequencies around 40 Hz. The mobility of oxygen atoms in the CuOx planes in the various phases has been discussed and the thermally activated peak of elastic energy dissipation observed around 500 K was interpreted in that framework. (C) 2004 Elsevier B.V. All rights reserved.

Influence of the estrous cycle on the behavior of rats in the elevated T-maze

The elevated T-maze is an animal anxiety model which can discriminate between anxiety-like and fear-like behaviors. The estrous cycle is an important variable of the response in animal anxiety tests and is known to affect other models. The aim of the present study was to investigate the influence of the estrous cycle on behavior displayed in the elevated T-maze test. Seventeen male and 60 female rats were submitted to one session in this test, with the females being screened for the estrous cycle and divided into groups according to the various phases. The elevated T-maze had three arms of equal dimensions (50 cm x 10 cm), one enclosed by 40-cm high walls and perpendicular to the others, the apparatus being elevated 50cm above the floor. Each rat was placed in the end of the enclosed arm and the latency for it to leave this arm was recorded. These measurements were repeated three times separated by 30-s intervals (passive avoidance). After trial 3, each rat was placed at the distal end of the right open arm and the latency to exit this arm was recorded. Whenever latencies were greater than 300 s the trial was finished. The results demonstrated females in diestrus exhibited anxiety-like behaviors while females in metaestrus behaved in a similar way as the males. There were no differences between groups in fear-like behaviors. The results also indicate the elevated T-maze to be a sensitive test to measure anxiety. (C) 2004 Elsevier B.V. All rights reserved.

Bounded solutions of fermions in the background of mixed vector-scalar inversely linear potentials

The problem of a fermion subject to a general mixing of vector and scalar potentials in a two-dimensional world is mapped into a Sturm-Liouville problem. Isolated bounded solutions are also searched. For the specific case of an inversely linear potential, which gives rise to an effective Kratzer potential in the Sturm-Liouville problem, exact bounded solutions are found in closed form. The case of a pure scalar potential with their isolated zero-energy solutions, already analyzed in a previous work, is obtained as a particular case. The behavior of the upper and lower components of the Dirac spinor is discussed in detail and some unusual results are revealed. The nonrelativistic limit of our results adds a new support to the conclusion that even-parity solutions to the nonrelativistic one-dimensional hydrogen atom do not exist. (c) 2004 Elsevier B.V. All rights reserved.

Thin polymer films prepared by plasma immersion ion implantation and deposition

This work describes an investigation of the properties of polymer films prepared by plasma immersion ion implantation and deposition. Films were synthesized from low pressure benzene glow discharges, biasing the samples with 25 W negative pulses. The total energy deposited in the growing layer was varied tailoring simultaneously pulse frequency and duty cycle. The effect of the pulse characteristics on the chemical composition and mechanical properties of the films was studied by X-ray photoelectron spectroscopy (XPS) and nanoindentation, respectively. Analysis of the deconvoluted C 1s XPS peaks demonstrated that oxygen was incorporated in all the samples. The chemical modifications induced structural reorganization, characterized by chain cross-linking and unsaturation, affecting material properties. Hardness and plastic resistance parameter increased under certain bombardment conditions. An interpretation is proposed in terms of the total energy delivered to the growing layer. (C) 2004 Elsevier B.V. All rights reserved.

Comportamento de parâmetros fisiológicos de homens e mulheres em condições de estresse laboral submetidos à técnica Watsu

The physiological variations of parameters in situations of laboral stress can function like indicator in the sprouting of disorder. Those conditions have led researchers to investigate alternatives that can favor the quality of life in persons under stress laboral. The present research had as objectives investigate the physiological behavior of parameters (blood pressure, heart hat and respiratory hat) of men and women in condition of stress laboral submitted to the technique Watsu. It was used a experimental methodology with a group formed by men and women in reproductive age, that work as salesclerk in a supermarket net in Natal/RN. The seven individuals selected were submitted to the three phases of the study (dependent groups), that consisted of the phase 1 of obtaining from the measure basal (control 1), in the phase 2 of immersion in the water (control 2), and phase 3 from the application the technique Watsu (experimental phase). It was verified that during the phase basal (condition 1) the physiological parameters (BPS, BPD, HH and RH) of both sexes evaluated showed the medium values of the women (average±detour-standard: BSP = 104.1±7.92; BPD = 70.83 ±7.92; HH = 77.58 ±3.87; RH = 19.83 ±2.58) similar those presented by the men (BPS = 118.75 ±7.55; BPD = 75.00 ±9.91; HH = 71.75 ±14.95; RH = 16.62 ±3.99). The evaluation of those parameters before and after immersion of the volunteers in the water (condition 2) showed a significant reduction (W = 3.0: p≤0.05) barely for the values of BPS presented by the sex females after immersion. In the men group, all of the physiological parameters analyzed did not vary significantly. Regarding the profile of those variables before and after application of the watsu (condition 3), was verified a significant increase (W= 0,0: p≤0.05) for the BPS one and SABP in the women. The Men did not show significant variation for all of the physiological parameters. Faced with the results presented, we are able to conclude that the systolic and diastolic blood pressures were the physiological parameters that are on influence from the Technique Watsu, only for the kind females

Evaluation of WC-17Co and WC-10Co-4Cr thermal spray coatings by HVOF on the fatigue and corrosion strength of AISI 4340 steel

It is known that chromium electroplating is related to the reduction in the fatigue strength of base metal. However, chromium results in protection against wear and corrosion combined with chemical resistance and good lubricity. Environmental requirements are an important point to be considered in the search for possible alternatives to hard chrome plating. Aircraft landing gear manufactures are considering WC thermal spray coating applied by the high-velocity oxygen-fuel (HVOF) process an alternative candidate, which shows performance at least comparable to results, obtained for hard chrome plating. The aim of this study is to compare the influence of WC-17Co and WC-10Co-4Cr coatings applied by HVOF process and hard chromium electroplating on the fatigue strength of AISI 4340 steel, with and without shot peening. S-N curves were obtained in axial fatigue test for base material, chromium plated and tungsten carbide coated specimens. Tungsten carbide thermal spray coating results in higher fatigue strength when compared to hard chromium electroplated. Shot peening prior to thermal spraying showed to be an excellent alternative to increase fatigue strength of AISI 4340 steel. Experimental data showed higher axial fatigue and corrosion resistance in salt fog exposure for samples WC-10Co-4Cr HVOF coated when compared with WC-17Co. Fracture surface analysis by scanning electron microscopy (SEM) indicated the existence of a uniform coverage of nearly all substrates. (C) 2004 Elsevier B.V. All rights reserved.

Modal transformation applied to double three-phase transmission lines

Double three-phase transmission lines are analyzed in this paper using a modal transformation model. The main attribute of this model is the use of a single real transformation matrix based on line geometrical characteristics and the Clarke matrix. Because of this, for any line point, the electrical values can be accessed for phase domain or mode domain using the considered transformation matrix and without convolution methods. For non-transposed symmetrical lines the errors between the model results and the exact modes are insignificant values. The eigenvector and eigenvalue analyses for transposed lines search the similarities among the three analyzed transposition types and the possible simplifications for a non-transposed case.

Electric load forecasting using a fuzzy ART&ARTMAP neural network

This work presents a neural network based on the ART architecture ( adaptive resonance theory), named fuzzy ART& ARTMAP neural network, applied to the electric load-forecasting problem. The neural networks based on the ARTarchitecture have two fundamental characteristics that are extremely important for the network performance ( stability and plasticity), which allow the implementation of continuous training. The fuzzy ART& ARTMAP neural network aims to reduce the imprecision of the forecasting results by a mechanism that separate the analog and binary data, processing them separately. Therefore, this represents a reduction on the processing time and improved quality of the results, when compared to the Back-Propagation neural network, and better to the classical forecasting techniques (ARIMA of Box and Jenkins methods). Finished the training, the fuzzy ART& ARTMAP neural network is capable to forecast electrical loads 24 h in advance. To validate the methodology, data from a Brazilian electric company is used. (C) 2004 Elsevier B.V. All rights reserved.