Effects of surface chemistry on aromatic compound adsorption from dilute aqueous solutions by activated carbon

Adsorption of one nondissociating and four dissociating aromatic compounds onto three untreated activated carbons from dilute aqueous solutions were investigated. All adsorption experiments were preformed in pH-controlled solutions. The experimental isotherms were analyzed using the homogeneous Langmuir model. The surface chemical properties of the activated carbons were characterized using a combination of water adsorption, X-ray photoemission spectroscopy, and mass titration. These data give rise to a new insight into the adsorption mechanism of aromatic solutes, in their molecular and ionic forms, onto untreated activated carbons. It was found that, for the hydrophilic activated carbons, the dominant adsorption forces were observed to be dipolar interactions when the solutes were in their molecular form whereas dispersive forces, such as pi-pi interactions, were most likely dominant in the case of the basic hydrophobic carbons. However, when the solutes were in their ionic form adsorption occurs in all cases through dispersive forces.

Conductivity/microstructure study of a pyrochlore-type ordered phase in the compound Zr0.75Ce0.08Nd0.17O1.92

The compound Zr0.75Ce0.08Nd0.17O1.92 was investigated as part of a much larger electrical conductivity/microstructure study of the systems ZrO2-CeO2-M2O3 (where M=Nd, Sm, ..., Yb) [Solid State Ionics (2002)]. Electrical conductivity measurements performed in air at 800 degreesC showed significant conductivity degradation over a period of 200 h. Investigation of the annealed and as-fired specimens by ATEM revealed the presence of an emerging, ordered pyrochlore-type phase within the Zr0.75Ce0.08Nd0.17O1.92 defect-fluorite solid solution at much lower dopant levels than observed previously for zirconia binary systems. (C) 2002 Elsevier Science B.V. All rights reserved.

Novel neutral iron(II) isocyanide maleonitrile dithiolate [Fe(S2C2(CN)2)(t-BuNC) 4] compound

FeBr2 reacts with the S2C2(CN)22- ion (1:1 ratio) in the presence of an excess of t-BuNC in THF to give the mixed ligand [Fe(S2C2(CN)2)(t-BuNC) 4] compound. This neutral product with a formal oxidation state of two for the iron atom was characterized by conductivity measurements, and, i.r., Mössbauer, 13C and 1H n.m.r. spectroscopy. There is a Fe-C p back-donation strengthened towards isocyanide ligands, according to the data of 13C, 1H n.m.r. and Mössbauer spectroscopy.

Synthesis of optimization of [11C] Pittsburgh compound B by the captive solvent method

Mestrado em Medicina Nuclear.

A new natural spiro heterocyclic compound and the cytotoxic activity of the secondary metabolites from Juniperus brevifolia leaves

Copyright © 2010 Elsevier B.V. All rights reserved.

Effects of emotional valence and three-dimensionality of visual stimuli on brain activation: an fMRI study

BACKGROUND: Examining changes in brain activation linked with emotion-inducing stimuli is essential to the study of emotions. Due to the ecological potential of techniques such as virtual reality (VR), inspection of whether brain activation in response to emotional stimuli can be modulated by the three-dimensional (3D) properties of the images is important. OBJECTIVE: The current study sought to test whether the activation of brain areas involved in the emotional processing of scenarios of different valences can be modulated by 3D. Therefore, the focus was made on the interaction effect between emotion-inducing stimuli of different emotional valences (pleasant, unpleasant and neutral valences) and visualization types (2D, 3D). However, main effects were also analyzed.METHODS: The effect of emotional valence and visualization types and their interaction were analyzed through a 3x2 repeated measures ANOVA. Post-hoc t-tests were performed under a ROI-analysis approach. RESULTS: The results show increased brain activation for the 3D affective-inducing stimuli in comparison with the same stimuli in 2D scenarios, mostly in cortical and subcortical regions that are related to emotional processing, in addition to visual processing regions. CONCLUSIONS: This study has the potential of clarify brain mechanisms involved in the processing of emotional stimuli (scenarios’ valence) and their interaction with three-dimensionality.

Insights into the mechanims underlyng the antiproliferative potential of a Co(II) coordination compound bearing 1,10-Phenanthroline-5,6-Dione: DNA and protein interaction studies

The very high antiproliferative activity of [Co(Cl)(H2O)(phendione)(2)][BF4] (phendione is 1,10-phenanthroline-5,6-dione) against three human tumor cell lines (half-maximal inhibitory concentration below 1 mu M) and its slight selectivity for the colorectal tumor cell line compared with healthy human fibroblasts led us to explore the mechanisms of action underlying this promising antitumor potential. As previously shown by our group, this complex induces cell cycle arrest in S phase and subsequent cell death by apoptosis and it also reduces the expression of proteins typically upregulated in tumors. In the present work, we demonstrate that [Co(Cl)(phendione)(2)(H2O)][BF4] (1) does not reduce the viability of nontumorigenic breast epithelial cells by more than 85 % at 1 mu M, (2) promotes the upregulation of proapoptotic Bax and cell-cycle-related p21, and (3) induces release of lactate dehydrogenase, which is partially reversed by ursodeoxycholic acid. DNA interaction studies were performed to uncover the genotoxicity of the complex and demonstrate that even though it displays K (b) (+/- A standard error of the mean) of (3.48 +/- A 0.03) x 10(5) M-1 and is able to produce double-strand breaks in a concentration-dependent manner, it does not exert any clastogenic effect ex vivo, ruling out DNA as a major cellular target for the complex. Steady-state and time-resolved fluorescence spectroscopy studies are indicative of a strong and specific interaction of the complex with human serum albumin, involving one binding site, at a distance of approximately 1.5 nm for the Trp214 indole side chain with log K (b) similar to 4.7, thus suggesting that this complex can be efficiently transported by albumin in the blood plasma.

Amygdala activation in response to 2D and 3D emotion-inducing stimuli

Studying changes in brain activation according to the valence of emotion-inducing stimuli is essential in the research on emotions. Due to the ecological potential of virtual reality, it is also important to examine whether brain activation in response to emotional stimuli can be modulated by the three-dimensional (3D) properties of the images. This study uses functional Magnetic Resonance Imaging to compare differences between 3D and standard (2D) visual stimuli in the activation of emotion-related brain areas. The stimuli were organized in three virtual-reality scenarios, each with a different emotional valence (pleasant, unpleasant and neutral). The scenarios were presented in a pseudo-randomized order in the two visualization modes to twelve healthy males. Data were analyzed through a GLM-based fixed effects procedure. Unpleasant and neutral stimuli activated the right amygdala more strongly when presented in 3D than in 2D. These results suggest that 3D stimuli, when used as “building blocks” for virtual environments, can induce increased emotional loading, as shown here through neuroimaging.

Simulation of the velocity field in compound channel flow using different closure models

1st European IAHR Congress,6-4 May, Edinburg, Scotland

Microglial clearance function: dependence on phenotypes

Dissertação para obtenção do Grau de Mestre em Genética Molecular e Biomedicina

Influence of Compound 16.842 on hookworm infections

Compound 16.842 was tried with three different groups of patients in order to evaluate its tolerancy, and efficacy as well, with a view of using the drug in mass campaigns against hookworm. Group I, used for a preliminary trial, consisted of 38 patients attending an out-patient clinic, and living either in the out-skirts or in the various urban areas of the city of Rio de Janeiro, including some inmates of an orphanage. Group II, a field trial, was carried out in two farms, where the drug was administered both to the positive cases (124) and to the rest of the population (nearly 90%). Group III, a field trial was also carried out in a small town where nearly 40% of the total population was treated with the Compound. Tolerability was considered rather satisfactory, mainly among the patients receiving two single doses (50-150mg), according to the age, 4 - 6 weeks apart). These results suggest that 2-4 courses of therapy within a shorter span of time should be the ideal for a mass treatment campaign. Efficacy varied from 26.6% to 76.2% parasitological cure in the various groups, with a wide range of variation also in the percent of mean reduction of eggs for hookworm. The drug showed also some effect against Ascaris lumbricoides giving cure rates between 10,5% and 35.7% in the various groups, with a percentage reduction in mean egg counts of 27% to 83.3% according to the various groups. It was concluded that Compound 16.842 possesses a marked effect on hookworm and a mild effect on A. lumbricoides. The findings indicate the need for more accurate studies to determine the most efficient schedules of treatment and the real value of the drug, as compared to other antihelminthics against the two parasites under study.

Experimental chemotherapy of Schistosomiasis III: laboratory and clinical trials with trichlorphone, an organophosphorus compound

Oogram studies have been carried out on mice, hamsters, and Cebus morikeys experimentally infected with Schistosoma mansoni and treated with trichlorphone (0,0-dimethyl 1-hydroxy-2, 2, 2-trichloroethylphosphonate). In mice, despite a slight hepatic shift of schistosomes, all animais presented oogram changes when dosed, per os, at the schedules of 200, and 100 mg/kg/day × 7. In hamsters, antischistosomal activity could be detected only at toxic leveis. In monkeys, trichlorphone showed insignificant action even after oral administration of 30 mg/kg/day for 10 consecutive days. In 5 volunteers, a sharp drop in cholinesterase plasma level was observed 24 hours after a single oral dose of 7.5 mg/kg. However, cholinesterase levels returned to the initial values within a period of 11 to 27 days. Trichlorphone was then administered to 12 schistosome patients (7.5 mg/kg/day, every fort- night, × 5). One month after therapy, interruption of egg laying was observed in 6 patients. Late parasitological control showed that all treated patients continued to pass viable S. mansoni eggs with their stools.

Exploring ionic liquids′ unique stimuli to elucidate uncharacterised cellular and molecular mechanisms in filamentous fungi

The emergence of new fungal pathogens, either of plants or animals, and the increasing number of reported cases of resistant human pathogenic strains to the available antifungal drugs reinforces the need for better understanding the biology of filamentous fungi. Conventional drugs target components of the fungal membrane or cell wall, therefore identifying novel intracellular targets, yet unique to fungi, is a global priority.(...)

Evaluation of motor neuron excitability by CMAP scanning with modulated current

It is important to have better evaluation and understanding of the motor neuron physiology, with the goal to early and objectively diagnose and treat patients with neurodegenerative pathologies. The Compound Muscle Action Potential (CMAP) scan is a non-invasive diagnosis technique for neurodegenerative pathologies, such as ALS, and enables a quick analysis of the muscle action potentials in response to motor nerve stimulation. This work aims to study the influence of different pulse modulated waveforms in peripheral nerve excitability by CMAP scan technique on healthy subjects. A total of 13 healthy subjects were submitted to the same test. The stimuli were applied in the medium nerve on the right wrist and electromyography signal collected on the Abductor Pollicis Brevis (APB) muscle surface on the right thumb. Stimulation was performed with an increasing intensities range from 4 to 30 mA, with varying steps, 3 stimuli per step. The procedure was repeated 4 times per subject, each repetition using a different single pulse stimulation waveform: monophasic square, monophasic triangular, monophasic quadratic and biphasic square. Results were retrieved from the averaging of the stimuli on each current intensity step. The square pulse needs less current intensity to generate the same response amplitude regarding the other waves and presents a more steep curve slope and this effect is gradually decreasing for the triangular and quadratic pulse,respectively, being the difference even more evident regarding the biphasic pulse. The control of the waveform stimulation pulse allows varying the stimulusresponse curve slope.