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Showing papers by "Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto published in 2006"


Journal ArticleDOI
TL;DR: It is proposed that the main functional role of electrical coupling is to provide an enhancement of dynamic range, therefore allowing the coding of information spanning several orders of magnitude, which could provide a microscopic neural basis for psychophysical laws.
Abstract: A recurrent idea in the study of complex systems is that optimal information processing is to be found near phase transitions. However, this heuristic hypothesis has few (if any) concrete realizations where a standard and biologically relevant quantity is optimized at criticality. Here we give a clear example of such a phenomenon: a network of excitable elements has its sensitivity and dynamic range maximized at the critical point of a non-equilibrium phase transition. Our results are compatible with the essential role of gap junctions in olfactory glomeruli and retinal ganglionar cell output. Synchronization and global oscillations also emerge from the network dynamics. We propose that the main functional role of electrical coupling is to provide an enhancement of dynamic range, therefore allowing the coding of information spanning several orders of magnitude. The mechanism could provide a microscopic neural basis for psychophysical laws.

794 citations


Journal ArticleDOI
TL;DR: To increase the frequency of homologous recombination, the KU80 homologue in Aspergillus fumigatus was inactivated and deletion had no influence on pathogenicity in a low-dose murine infection model.
Abstract: To increase the frequency of homologous recombination, we inactivated the KU80 homologue in Aspergillus fumigatus (named akuBKU80). Homologous integration reached about 80% for both calcineurin A (calA) and polyketide synthase pksP (alb1) genes in the akuBKU80 mutant to 3 and 5%, respectively, when using a wild-type A. fumigatus strain. Deletion of akuBKU80 had no influence on pathogenicity in a low-dose murine infection model.

375 citations


Journal ArticleDOI
TL;DR: Fluorescence spectroscopy is one of the noninvasive methods that can identify diseases and promote increasing the knowledge in medical diagnosis as mentioned in this paper, and it can identify chromophores, fluorophores as identified by applied fluorescence techniques.
Abstract: Fluorescence of the skin, enamel, dentin, and bone are reviewed. Fluorescence spectroscopy is one of the noninvasive methods that can identify diseases and promote increasing the knowledge in medical diagnosis. The microstructure and composition of biological tissues are presented, followed by a description of chromophores, fluorophores as identified by use of applied fluorescence techniques.

144 citations


Journal ArticleDOI
TL;DR: This study contributes to catalogue soil fungi isolated in the state of Sao Paulo, and provides additional information to support future research about the industrial potential of these microorganisms that may produce enzymes and, eventually, also secondary metabolites with anti-microbial or anti-parasitic activities.

122 citations


Journal ArticleDOI
TL;DR: These findings support the contention that serotonin and GABAergic neurons may act in concert in the modulation of defense reaction in the midbrain tectum, and indicate a direct neural pathway connecting the dorsal midbrain and monoaminergic nuclei of the descending pain inhibitory system.

103 citations


Journal ArticleDOI
TL;DR: The results indicated the potential applicability of LDHs as supports for the preparation of slow release formulations of acid herbicides such as 2,4-D, MCPA, or picloram.
Abstract: A Mg/Al layered double hydroxide (LDH) was intercalated with the anionic herbicides 2,4-D, MCPA, and picloram by using three different methodologies: (i) direct synthesis (DS), (ii) regeneration (RE), and (iii) ion exchange (IE). The resulting complexes were characterized and assayed by batch release and column leaching tests, aiming at the controlled release of these herbicides. All the tested LDH-herbicide complexes displayed similar slow herbicide release properties in water, although the IE method seemed to result in complexes with a greater fraction of herbicide in a readily available form. Apparently, the LDH-herbicide complexes released most of the active ingredient present in the complexes at the end of the batch release experiment. This was attributed to the replacement of the intercalated herbicide by carbonate and hydroxyl anions from the aqueous solution. Compared to the free herbicides, the application of the three LDH-herbicide complexes (RE) to soil columns resulted in reduction in the maximum herbicide concentration in leachates and led to the retardation of herbicide leaching through the soil. All LDH-herbicide complexes presented an herbicidal efficacy similar to that of the free (technical) herbicides. Our results indicated the potential applicability of LDHs as supports for the preparation of slow release formulations of acid herbicides such as 2,4-D, MCPA, or picloram.

97 citations


Journal ArticleDOI
TL;DR: Cette observation a conduit a emettre l'hypothese que la determination des castes chez Melipona a peut-etre une base genetique ne concordent pas necessairement.
Abstract: Le nombre d'especes et la variabilite des caracteres ecologiques et ethologiques rendent les abeilles sans aiguillon remarquables et en font un groupe interessant pour rechercher des correlations entre les caracteres du cycle evolutif d'une part et les mecanismes physiologiques et genetiques qui sous-tendent le developpement des castes, la reproduction et la division du travail d'autre part. Dans cette synthese nous mettons en contraste les nombreuses observations sur les abeilles sans aiguillon avec celles de leur groupe soeur, les abeilles domestiques. Toutes les abeilles sans aiguillon approvisionnent en masse les cellules de leur couvain avant que la reine ne ponde un oeuf et ne l'opercule. Il y a neanmoins des differences remarquables dans la structure du nid a couvain et dans la maniere dont les reines, les ouvrieres et les mâles sont eleves (Fig. 1). Dans le groupe des trigones, les reines sont produites dans de grandes cellules a couvain ou dans des cellules construites les unes sur les autres, ce qui permet aux larves d'ingerer beaucoup plus de nourriture. Dans le genre Melipona au contraire, toutes les cellules de couvain sont de meme taille et un nombre relativement eleve de reines emerge de ces cellules dans des conditions optimales de la colonie. Cette observation a conduit a emettre l'hypothese que la determination des castes chez Melipona a peut-etre une base genetique. Bien qu'elle ait ete proposee il y a plus de 50 ans, cette hypothese n'ajamais ete validee de facon concluante. Selon les recherches en cours, les marqueurs genetiques generes par un protocole AFLP se separent en fonction du phenotype de la caste (Fig. 2). D'autres preuves proviennent d'une analyse de l'expression genique differentielle sur des reines recemment ecloses et des ouvrieres de Melipona quadrifasciata. Cette etude a ete produite sur 1200 ESTs (etiquettes de sequences exprimees) qui ont ete comparees aux profils d'expression genique specifiques des castes chez Apis mellifera, soulignant l'importance de la regulation metabolique dans le developpement des castes. Nous avons teste les profils d'expression de cinq des genes representes par les ESTs dans une comparaison entre reines naturelles et ouvrieres et reines induites par un traitement hormonal des larves au stade de filage du cocon ; nous avons constate que les adultes issus des larves traitees par hormones sur-exprimaient la plupart de ces genes marqueurs, meme s'ils presentaient le phenotype de reine (Fig. 3). Ceci indique que le phenotype morphologique et le profil d'expression genique ne concordent pas necessairement. Il existe aussi chez les abeilles sans aiguillon une forte variation en ce qui concerne la reproduction des ouvrieres, certaines especes presentant une contribution significative des ouvrieres a la production des mâles. Chez de nombreuses especes, les ouvrieres produisent des oeufs trophiques qui sont consommes par la reine peu de temps avant qu'elle ne ponde dans une cellule fraichement approvisionnee. Chez certaines especes, pourtant, la reproduction des ouvrieres est completement bloquee par la degenerescence des ovaires au cours du developpement nymphal. Ces differences dans les strategies de reproduction des ouvrieres se refletent dans les differences de l'expression genique de la vitellogenine et dans les teneurs de l'hemolymphe en vitellogenine. (Fig. 4).

92 citations


Journal ArticleDOI
TL;DR: The findings indicate that DA mechanisms mediated by D2 receptors are mainly involved in the expression rather than in the acquisition of fear.
Abstract: The increase in the startle reflex in the presence of a stimulus that has been previously paired to foot shock is taken as an index of anxiety and named fear potentiated startle (FPS). Freezing behavior, defined as a cessation of all observable movements except those associated with respiration, has also been used as an index of fear in rats. Recently, a growing body of evidence has suggested that dopaminergic mechanisms are significant for different aspects of affective memory, namely its formation, expression or retrieval. However, the results of studies that have directly examined the ability of the dopaminergic system to influence fear have been inconsistent. This work is aimed at examining the involvement of D1 and D2 receptors in the acquisition and expression of conditioned fear using the fear potentiated startle test and the freezing behavior. We evaluated the effects of systemic administration of the D1 antagonist SCH 23390, the D1 agonist SKF 38393, the D2 antagonist sulpiride and the D2 agonist quinpirole before and after conditioning on FPS and freezing as indices of fear memory. The motor activity of the animals was also evaluated in an open field test. Injections of SCH 23390, SKF 38393, sulpiride and quinpirole before conditioning sessions did not produce any significant effect on FPS, but SCH 23390 decreased freezing. Injections of SCH 23390, SKF 38393 and sulpiride before testing session did not produce any significant effect on FPS or freezing. Quinpirole caused significant reduction in FPS and freezing when injected before testing. Drugs' actions were not due to nonspecific impairments in the ability to respond to the CS because the identical drug treatments had no effect in an open field test. Our findings indicate that DA mechanisms mediated by D2 receptors are mainly involved in the expression rather than in the acquisition of fear.

83 citations


Journal ArticleDOI
TL;DR: In this article, the capacity of calcined Mg-Al-CO 3 -LDH to remove the acid herbicides 2,4-D, MCPA and Picloram from aqueous solution, as well as investigate the influence of pH on the regeneration process.

82 citations


Journal ArticleDOI
TL;DR: The honey bee queen and worker castes are a model system for developmental plasticity and reproduction and a first genome‐based initiative to provide an annotated framework for trends in gene regulation during female caste differentiation and reproduction is provided.
Abstract: The honey bee queen and worker castes are a model system for developmental plasticity. We used established expressed sequence tag information for a Gene Ontology based annotation of genes that are differentially expressed during caste development. Metabolic regulation emerged as a major theme, with a caste-specific difference in the expression of oxidoreductases vs. hydrolases. Motif searches in upstream regions revealed group-specific motifs, providing an entry point to cis-regulatory network studies on caste genes. For genes putatively involved in reproduction, meiosis-associated factors came out as highly conserved, whereas some determinants of embryonic axes either do not have clear orthologs (bag of marbles, gurken, torso), or appear to be lacking (trunk) in the bee genome. Our results are the outcome of a first genome-based initiative to provide an annotated framework for trends in gene regulation during female caste differentiation (representing developmental plasticity) and reproduction.

79 citations


Journal ArticleDOI
TL;DR: Examination of the influence of chemical inactivation of these nuclei of amygdala on the freezing and escape responses induced by electrical stimulation through electrodes implanted in the dPAG of Wistar rats shows that the amygdala can affect some, but not all, aspects of unconditioned freezing.

Journal ArticleDOI
TL;DR: In this paper, the photochemical and pharmacological studies of the novel [Ru(L)(tpy)NO]3+ L = bpy (2,2′-bipyridine), NH·-NHq (quinonediimine) and NH2.NH2cat (o-phenylenediamine) were investigated in aqueous medium.

Journal ArticleDOI
TL;DR: In conclusion, anxiogenic prenatal stress effects in the elevated plus‐maze could only be detected at early adulthood, not before, and at late adolescence (45 days of age) prenatal stress leaded to an anxiolytic‐like effect which can be interpreted as increased risk‐taking behavior.

Journal ArticleDOI
TL;DR: In this paper, a layer-by-layer (LbL) films of PAMAM dendrimers incorporating platinum nanoparticles (Pt-PAMAM) alternated with poly(vinylsulfonic acid) (PVS) were obtained via chemical reduction of H2PtCl6, using formic acid as reducing agent.

Journal ArticleDOI
TL;DR: In this article, the interaction between fisetin (3,3,4,7-tetrahydroxyflavone) and cyclodextrins (CDs) (alpha and beta) was studied through UV-vis absorption, steady-state fluorescence, induced circular dichroism, and (1)H NMR experiments with dependence on temperature and pH.
Abstract: In this work, the interaction between fisetin (3,3',4',7-tetrahydroxyflavone) (Fis) and cyclodextrins (CDs) (alpha and beta) was studied through UV-vis absorption, steady-state fluorescence, induced circular dichroism, and (1)H NMR experiments with dependence on temperature and pH. Some experimental data were compared with quantum-mechanics studies based on the SAM1 (AMPAC) semiempirical model, as well as with the B3LYP and MPW1PW91 functional models from density functional theory using the 6-311G and 3-21G basis sets. The spectroscopic measurements show that Fis does not form stable complexes with alpha-CD. On the other hand, at pH 4.0 and 6.5, the complex Fis-beta-CD is formed in a Fis:beta-CD 1:1 stoichiometry and an equilibrium constant (K) of 900 +/- 100 M(-1). In basic medium (pH 11.5), K decreases to 240 +/- 90 M(-1) because Fis deprotonation leads to its better solubilization in water. Molecular modeling points out that Fis is not totally inserted into the inner cavity of beta-CD. The formation of the inclusion complex renders an environment that enhances intramolecular excited state proton transfer. The inclusion complex is formed preferentially via entry of the Fis phenyl group into beta-CD.

Journal ArticleDOI
26 Sep 2006-Langmuir
TL;DR: The insertion of the enzyme at DPPG monolayers caused an increase in the dynamic surface elasticity at 30 mN m(-)(1), indicating a strong interaction between the enzyme and lipid molecules at a high-surface packing.
Abstract: This paper reports the surface activity of phytase at the air-water interface, its interaction with lipid monolayers, and the construction of a new phytic acid biosensor on the basis of the Langmuir-Blodgett (LB) technique. Phytase was inserted in the subphase solution of dipalmitoylphosphatidylglycerol (DPPG) Langmuir monolayers, and its incorporation to the air-water interface was monitored with surface pressure measurements. Phytase was able to incorporate into DPPG monolayers even at high surface pressures, ca. 30 mN/m, under controlled ionic strength, pH, and temperature. Mixed Langmuir monolayers of phytase and DPPG were characterized by surface pressure-area and surface potential-area isotherms, and the presence of the enzyme provided an expansion in the monolayers (when compared to the pure lipid at the interface). The enzyme incorporation also led to significant changes in the equilibrium surface compressibility (in-plane elasticity), especially in liquid-expanded and liquid-condensed regions. The dynamic surface elasticity for phytase-containing interfaces was investigated using harmonic oscillation and axisymmetric drop shape analysis. The insertion of the enzyme at DPPG monolayers caused an increase in the dynamic surface elasticity at 30 mN m(-)(1), indicating a strong interaction between the enzyme and lipid molecules at a high-surface packing. Langmuir-Blodgett (LB) films containing 35 layers of mixed phytase-DPPG were characterized by ultraviolet-visible and fluorescence spectroscopy and crystal quartz microbalance nanogravimetry. The ability in detecting phytic acid was studied with voltammetric measurements.

Journal ArticleDOI
30 Sep 2006
TL;DR: In this article, the authors examine how the low-income population articulates symbolic elements from various sources in order to organize dietetic rules that eventually become cultural indicators through which food is categorized as appropriate or harmful for consumption.
Abstract: Hunger is a natural need that must be satisfied through the ingestion of food in order to ensure the production and reproduction of human existence. However, if appeasing hunger is a natural and universal action, alimentation practices are also universal. They are not natural, but are situated in the scope of culture, that is to say, in the field of symbolic systems. Around commensality, each society designs a complex system of dietetic rules based on common sense, religious precepts and medical knowledge, which creates interdictions to exclude foods that are symbolically classified as harmful or dangerous to health from its menu. Anthropological studies have shown the diversity of alimentary practices, which do not constitute a solitary act, but are social activities including the production, processing and consumption of food and how societies construct their own representations, thus defining their identity in relation to other societies through their eating habits. This study examines how the low-income population articulates symbolic elements from various sources in order to organize dietetic rules that eventually become cultural indicators through which food is categorized as appropriate or harmful for consumption. Food is a category that establishes boundaries between the identity of the poor population, who faces difficulty to promote alimentation, and the identity of those whose culinary is rich and varied and that of the very poor, who starve.

Journal ArticleDOI
TL;DR: Kaurenoic and pimaradienoic acids, which are the main secondary metabolites isolated by the research group from the roots of Viguiera robusta and V. arenaria, show that these diterpenoids are able to inhibit the vascular contractility mainly by blocking extracellular Ca(2+) influx.

Journal ArticleDOI
TL;DR: Pt-Mo alloy catalysts were found to be more active than Pt-alone catalysts for ethanol oxidization as mentioned in this paper, and they showed that low molybdenum content in the electrode material enhances the activity toward ethanol oxidation when compared to Pt alone.
Abstract: Pt–Mo alloy electrocatalysts were prepared by an arc-melting furnace process to investigate the origin of their enhanced activity toward ethanol oxidation. Two Mo contents were chosen in zones of the binary phase diagram where they are supposed to form either a pure alloy mixture or a solid solution. Pt–Mo alloy catalysts were more active than Pt-alone. Gradual Mo dissolution at the electrode surface was observed after voltammetric and chronoamperometric measurements. The dissolved Mo contributed to the catalytic effect of the electrode as underpotentially deposited (upd) adatoms. This dissolution probably also leads to an increase in the electrode surface roughness. Low molybdenum content in the electrode material enhances the activity toward ethanol oxidation when compared to Pt-alone. Ethanol oxidation was also investigated by in situ infrared reflectance spectroscopy in order to determine the presence of adsorbed intermediates like CO species. Acetaldehyde, acetic acid and CO2 were also found by spectroscopic experiments.

Journal ArticleDOI
TL;DR: In this article, a method for the controlled, sequential design of a bilayer polymer cell architecture that consists of a large interface area with connecting paths to the respective electrodes for both materials is presented.
Abstract: Significant progress is being made in the photovoltaic energy conversion using organic semiconducting materials. One of the focuses of attention is the morphology of the donor−acceptor heterojunction at the nanometer scale, to ensure efficient charge generation and loss-free charge transport at the same time. Here, we present a method for the controlled, sequential design of a bilayer polymer cell architecture that consists of a large interface area with connecting paths to the respective electrodes for both materials. We used the surface-directed demixing of a donor conjugated/guest polymer blend during spin coating to produce a nanostructured interface, which was, after removal of the guest with a selective solvent, covered with an acceptor layer. With use of a donor poly(p-phenylenevinylene) derivative and the acceptor C60 fullerene, this resulted in much-improved device performance, with external power efficiencies more than 3 times higher than those reported for that particular material combination s...

Journal ArticleDOI
TL;DR: It is suggested that EV exerts anxiolytic-like effects on a specific subset of defensive behaviors which have been associated with generalized anxiety disorder, in contrast to the reference drug imipramine that significantly decreased immobility time after chronic treatment.
Abstract: Erythrina velutina (EV) and Erythrina mulungu (EM), popularly used in Brazil as tranquilizing agents, were studied. The effects of acute and chronic oral treatment with a water:alcohol extract of EV (7:3, plant grounded stem bark; acute = 100, 200, 400 mg/kg; chronic = 50, 100, 200 mg/kg) were evaluated in rats (N = 11-12) submitted to the elevated T-maze (for avoidance and escape measurements) model of anxiety. This model was selected for its presumed capacity to elicit specific subtypes of anxiety disorders recognized in clinical practice: avoidance has been related to generalized anxiety and escape to panic. Additionally, animals were treated with the same doses of EV and EM (water:alcohol 7:3, inflorescence extract) and submitted to the forced swim test for the evaluation of antidepressant activity (N = 7-10). Both treatment regimens with EV impaired elevated T-maze avoidance latencies, without altering escape, in a way similar to the reference drug diazepam (avoidance 1, mean ± SEM, acute study: 131.1 ± 45.5 (control), 9.0 ± 3.3 (diazepam), 12.7 ± 2.9 (200 mg/kg), 28.8 ± 15.3 (400 mg/kg); chronic study: 131.7 ± 46.9 (control), 35.8 ± 29.7 (diazepam), 24.4 ± 10.4 (50 mg/kg), 29.7 ± 11.5 (200 mg/kg)). Neither EV nor EM altered measurements performed in the forced swim test, in contrast to the reference drug imipramine that significantly decreased immobility time after chronic treatment. These results were not due to motor alterations since no significant effects were detected in an open field. These observations suggest that EV exerts anxiolytic-like effects on a specific subset of defensive behaviors which have been associated with generalized anxiety disorder.

Journal ArticleDOI
TL;DR: Semiquantitative and quantitative RT-PCR with specific primers allowed for an analysis of mRNA levels during worker bee development and under different physiological conditions, which revealed a glutamine-rich polypeptide with a predicted molecular mass of 112.2 kDa and pI of 6.43.
Abstract: An N-terminal amino acid sequence of a previously reported honey bee hexamerin, HEX 110 [Danty et al., Insect Biochem Mol Biol 28:387-397 (1998)], was used as reference to identify the predicted genomic sequence in a public GenBank database. In silico analysis revealed an ORF of 3,033 nucleotides that encompasses eight exons. The conceptual translation product is a glutamine-rich polypeptide with a predicted molecular mass of 112.2 kDa and pI of 6.43, which contains the conserved M and C hemocyanin domains. Semiquantitative and quantitative RT-PCR with specific primers allowed for an analysis of mRNA levels during worker bee development and under different physiological conditions. Concomitantly, the abundance of the respective polypeptide in the hemolymph was examined by SDS-PAGE. Hex 110 transcripts were found in high levels during the larval stages, then decreased gradually during the pupal stage, and increased again in adults. HEX 110 subunits were highly abundant in larval hemolymph, decreased at the spinning-stage, and remained at low levels in pupae and adults. In 5th instar larvae, neither starvation nor supplementation of larval food with royal jelly changed the Hex 110 transcript levels or the amounts of HEX 110 subunit in hemolymph. In adult workers, high levels of Hex 110 mRNA, but not of the respective subunit, were related to ovary activation, and also to the consumption of a pollen-rich diet.

Journal ArticleDOI
TL;DR: Ces resultats montrent que des mesures d'une petite partie du corps de l'abeille sont suffisantes pour discriminer les sous-especes.
Abstract: La morphometrie a joue depuis longtemps un role important dans les etudes de taxonomie. Lorsqu'elle est couplee aux statistiques multivariees, c'est un outil tres puissant pour les analyses discriminantes et donc-pour l'identification des especes. Chez Apis mellifera de nombreuses differences entre sous-especes sont quantitatives et les diverses etudes menees jusqu'a present ont toujours utilise les mesures de diverses parties du corps de l'abeille. Afin de simplifier et d'accelerer les analyses, nous avons mesure 11 caracteristiques d'une seule cellule de l'aile anterieure pour savoir si les differences dans cette cellule permettaient de discriminer les trois sous-especes A. mellifera ligustica, A. m. camica et les abeilles africanisees du Bresil. Une analyse en composantes principales a ete effectuee sur les mesures afin de determiner si notre corpus de donnees formait trois groupements distincts (Fig. 3). Ceux-ci ont ete verifies par une analyse discriminante (Fig. 4). Les caracteristiques retenues forment bien trois groupes significativement differents (P < 0,00001) et la fonction discriminative lineaire a pu classer correctement 98,7 % des echantillons. Ces resultats montrent que des mesures d'une petite partie du corps de l'abeille sont suffisantes pour discriminer les sous-especes.

Journal ArticleDOI
TL;DR: Fluoxetine appears to restore the serotoninergic function in brain areas recruited by intense contextual fear conditioning in rats under intense fear conditioning, which may underlie its reported efficacy in the pharmacotherapy of panic disorders.

Journal ArticleDOI
TL;DR: Phytochemical analysis of the antioxidant ethanolic extract of Alternanthera tenella Colla led to the isolation of six flavonoids, acacetin 8-C and quercetin, which showed antioxidant activity in vitro.
Abstract: Phytochemical analysis of the antioxidant ethanolic extract of Alternanthera tenella Colla led to the isolation of six flavonoids, acacetin 8-C-[alpha-L-rhamnopyranosyl-(1 --> 2)-beta-D-glucopyranoside] (1), 2"-O-alpha-L-rhamnopyranosyl-vitexin (2), 2"-O-beta-D-glucopyranosyl-vitexin (3), vitexin (4), quercetin (5) and kaempferol (6). All the structures were established by ESI-MS and NMR spectroscopic methods. Antioxidant capacity of extract, fractions and isolated compounds was determined using the oxygen radical absorbance capacity (ORAC) assay and extract, fractions and flavonoids isolated showed antioxidant activity in vitro. Moreover, the total soluble phenolic contents of the extract and fractions were measured using the Folin-Ciocalteau reagent and the quantitative analysis of flavone C-glycosides major constituents was performed by HPLC.

Journal ArticleDOI
TL;DR: In this paper, the performance of Pt-RuO 2 catalysts in the form of pure powder or supported on carbon powder (Vulcan XC72) substrate was investigated in a single direct methanol fuel cell (DMFC).

Journal ArticleDOI
TL;DR: The proposed method, using a lab-made SPME-LC interface, allowed the determination of tricyclic antidepressants in in plasma at therapeutic concentration levels.
Abstract: Solid-phase microextraction (SPME)‐liquid chromatography (LC) is used to analyze tricyclic antidepressant drugs desipramine, imipramine, nortriptyline, amitriptyline, and clomipramine (internal standard) in plasma samples. Extraction conditions are optimized using a 23 factorial design plus a central point to evaluate the influence of the time, temperature, and matrix pH. A Polydimethylsiloxane‐divinylbenzene (60-µm film thickness) fiber is selected after the assessment of different types of coating. The chromatographic separation is realized using a C 18 column (150 × 4.6 mm, 5-µm particles), ammonium acetate buffer (0.05 mol/L, pH 5.50)‐acetonitrile (55:45 v/v) with 0.1% of triethylamine as mobile phase and UV‐vis detection at 214 nm. Among the factorial design conditions evaluated, the best results are obtained at a pH 1 1.0, temperature of 30°C, and extraction time of 45 min. The proposed method, using a lab-made SPME‐LC interface, allowed the determination of tricyclic antidepressants in in plasma at therapeutic concentration levels.

Journal ArticleDOI
TL;DR: Videodensitometric computer analysis of scan images may be used to identify vulnerable and potentially unstable lipid-rich carotid plaques, which are less echogenic in density than stable or asymptomatic, more densely fibrotic plaques.
Abstract: Background To establish the correlation between quantitative analysis based on B-mode ultrasound images of vulnerable carotid plaque and histological examination of the surgically removed plaque, on the basis of a videodensitometric digital texture characterization.

Journal ArticleDOI
TL;DR: In this article, the synthesis, characterization, and electrochemical properties of vanadium pentoxide xerogel-poly(ethylene oxide) hybrid materials obtained by varying the average molecular weight of the organic component as well as the components' ratios were reported.

Journal ArticleDOI
TL;DR: In this paper, a cyanine dye with absorption edges of almost 1000 nm was used in combination with MEH-PPV for the fabrication of organic solar cells, where a pronounced phase separation between the two components occurred and resulted in photocurrents with different signs for bilayer and bulk heterojunction devices.