Development and validation of infrared spectroscopy method for the determination of darunavir in tabets

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Synthesis and characterization of nanostructured TiO2-SnO2 composite

Nanostructured composites based on titanium dioxide have been studied in order to improve optical and photo-catalytic properties, as well as their performance in gas sensors. In this work, titanium and tin dioxides were simultaneously synthesized by the polyol method resulting in TiO2 platelet coated with SnO2 nanoparticles as was observed by scanning electron microscopy. The thermal analysis showed that the combined synthesis promotes more easily the crystallization of the TiO2 rutile phase. The composite obtained after heat treatment at 500 °C showed to be formed of almost only rutile phases of both oxides. The optical properties analyzed by UV-Vis spectroscopy showed that the combined oxides have higher absorbance, which reinforces a model found in the literature based on the flow of photo-generated electrons to the conduction band of SnO2 delaying the recombination of charges.

Lipophilicity as a determinant of binding of procaine analogs to rat alpha(3)beta(4) nicotinic acetylcholine receptor

Nicotinic acetylcholine receptors (nAChRs) have been studied in detail with regard to their interaction with therapeutic and drug addiction-related compounds. Using a structureactivity approach, we have examined the relationship among the molecular features of a set of eight para-R-substituted N,N-[(dimethylamino)ethyl] benzoate hydrochlorides, structurally related to procaine and their affinity for the a3 beta 4 nAChR heterologously expressed in KXa3 beta 4R2 cells. Affinity values (log[1/IC50]) of these compounds for the a3 beta 4 nAChR were determined by their competition with [3H]TCP binding. Log(1/IC50) values were analyzed considering different hydrophobic and electronic parameters and those related to molar refractivity. These have been experimentally determined or were taken from published literature. In accordance with literature observations, the generated cross-validated quantitative structureactivity relationship (QSAR) equations indicated a significant contribution of hydrophobic term to binding affinity of procaine analogs to the receptor and predicted affinity values for several local anesthetics (LAs) sets taken from the literature. The predicted values by using the QSAR model correlated well with the published values both for neuronal and for electroplaque nAChRs. Our work also reveals the general structure features of LAs that are important for interaction with nAChRs as well as the structural modifications that could be made to enhance binding affinity. (c) 2012 Wiley Periodicals, Inc.

Endothelin-1 induces neutrophil recruitment in adaptive inflammation via TNF alpha and CXCL1/CXCR2 in mice

Endothelin mediates neutrophil recruitment during innate inflammation. Herein we address whether endothelin-1 (ET-1) is involved in neutrophil recruitment in adaptive inflammation in mice, and its mechanisms. Pharmacological treatments were used to determine the role of endothelin in neutrophil recruitment to the peritoneal cavity of mice challenged with antigen (ovalbumin) or ET-1. Levels of ET-1, tumour necrosis factor a (TNF alpha), and CXC chemokine ligand 1 (CXCL1) were determined by enzyme-linked immunosorbent assay. Neutrophil migration and flow cytometry analyses were performed 4 h after the intraperitoneal stimulus. ET-1 induced dose-dependent neutrophil recruitment to the peritoneal cavity. Treatment with the non-selective ETA/ETB receptor antagonist bosentan, and selective ETA or ETB receptor antagonists BQ-123 or BQ-788, respectively, inhibited ET-1- and ovalbumin-induced neutrophil migration to the peritoneal cavity. In agreement with the above, the antigen challenge significantly increased levels of ET-1 in peritoneal exudates. The ET-1- and ovalbumin-induced neutrophil recruitment were reduced in TNFR1 deficient mice, and by treatments targeting CXCL1 or CXC chemokine receptor 2 (CXCR2); further, treatment with bosentan, BQ-123, or BQ-788 inhibited ET-1- and antigen-induced production of TNFa and CXCL1. Furthermore, ET-1 and ovalbumin challenge induced an increase in the number of cells expressing the Gr1(+) markers in the granulocyte gate, CD11c+ markers in the monocyte gate, and CD4(+) and CD45(+) (B220) markers in the lymphocyte gate in an ETA-and ETB-dependent manner, as determined by flow cytometry analysis, suggesting that ET-1 might be involved in the recruitment of neutrophils and other cells in adaptive inflammation. Therefore, the present study demonstrates that ET-1 is an important mediator for neutrophil recruitment in adaptive inflammation via TNF alpha and CXCL1/CXCR2-dependent mechanism.

Electroluminescence and electric current response spectroscopy applied to the characterization of polymer light-emitting electrochemical cells

Frequency-dependent electroluminescence and electric current response spectroscopy were applied to polymeric light-emitting electrochemical cells in order to obtain information about the operation mechanism regimes of such devices. Three clearly distinct frequency regimes could be identified: a dielectric regime at high frequencies; an ionic transport regime, characterized by ionic drift and electronic diffusion; and an electrolytic regime, characterized by electronic injection from the electrodes and electrochemical doping of the conjugated polymer. From the analysis of the results, it was possible to evaluate parameters like the diffusion speed of electronic charge carriers in the active layer and the voltage drop necessary for operation. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4752438]

Interaction between bradykinin potentiating nonapeptide (BPP9a) and beta-cyclodextrin: A structural and thermodynamic study

Herein, we demonstrate the physical and chemical characterizations of the supramolecular complex formed between beta-cyclodextrin (beta CD) and bradykinin potentiating nonapeptide (BPP9a), an endogenous toxin found in Bothrops jararaca. Circular dichroism results indicate a conformational change in the BPP9a secondary structure upon its complexation with beta CD. Nuclear magnetic resonance results, mainly from NOESY experiments, and theoretical calculations showed a favorable interaction between the tryptophan residue of BPP9a and the beta CD cavity. Thermodynamic inclusion parameters were investigated by isothermal titration calorimetry, demonstrating that beta CD/BPP9a complex formation is an exothermic process that results in a reduction in entropy. Additionally, in vitro degradation study of BPP9a against trypsin (37 degrees C, pH 7.2) showed higher stability of peptide in presence of beta CD. This beta CD/BPP9a complex, which presents new chemical properties arising from the peptide inclusion process, may be useful as an antihypertensive drug in oral pharmaceutical formulations. (C) 2011 Elsevier B.V. All rights reserved.

A marker-and-cell approach to free surface 2-D multiphase flows

This work describes a methodology to simulate free surface incompressible multiphase flows. This novel methodology allows the simulation of multiphase flows with an arbitrary number of phases, each of them having different densities and viscosities. Surface and interfacial tension effects are also included. The numerical technique is based on the GENSMAC front-tracking method. The velocity field is computed using a finite-difference discretization of a modification of the NavierStokes equations. These equations together with the continuity equation are solved for the two-dimensional multiphase flows, with different densities and viscosities in the different phases. The governing equations are solved on a regular Eulerian grid, and a Lagrangian mesh is employed to track free surfaces and interfaces. The method is validated by comparing numerical with analytic results for a number of simple problems; it was also employed to simulate complex problems for which no analytic solutions are available. The method presented in this paper has been shown to be robust and computationally efficient. Copyright (c) 2012 John Wiley & Sons, Ltd.

Xylanase and beta-Xylosidase Production by Aspergillus ochraceus: New Perspectives for the Application of Wheat Straw Autohydrolysis Liquor

The xylanase biosynthesis is induced by its substrate-xylan. The high xylan content in some wastes such as wheat residues (wheat bran and wheat straw) makes them accessible and cheap sources of inducers to be mainly applied in great volumes of fermentation, such as those of industrial bioreactors. Thus, in this work, the main proposal was incorporated in the nutrient medium wheat straw particles decomposed to soluble compounds (liquor) through treatment of lignocellulosic materials in autohydrolysis process, as a strategy to increase and undervalue xylanase production by Aspergillus ochraceus. The wheat straw autohydrolysis liquor produced in several conditions was used as a sole carbon source or with wheat bran. The best conditions for xylanase and beta-xylosidase production were observed when A. ochraceus was cultivated with 1% wheat bran added of 10% wheat straw liquor (produced after 15 min of hydrothermal treatment) as carbon source. This substrate was more favorable when compared with xylan, wheat bran, and wheat straw autohydrolysis liquor used separately. The application of this substrate mixture in a stirred tank bioreactor indicated the possibility of scaling up the process to commercial production.

The effect of sodium fluoride preservative and storage temperature on the stability of cocaine in horse blood, sheep vitreous and deer muscle

The in vitro stability of cocaine in horse blood, sheep vitreous humour (VH) and homogenised deer muscle is described. The stability of cocaine in horse blood was of interest because many toxicology laboratories utilise horse blood for the preparation of calibration and check standards and the latter are typically stored during routine use. The storage stability of cocaine in human VH and muscle has not been previously reported. In the absence of blank human VH and muscle, cocaine stability under varying conditions was demonstrated in animal tissues. Blood and VH were stored with and without addition of NaF at room temperature (RT), 4 degrees C and -18 degrees C for 84 days. Muscle homogenates were prepared in water, water/2% NaF, and phosphate buffer (pH 6.0)/2% NaF, and stored for 31 days at RT, 4 degrees C and -18 degrees C. Cocaine stability in human muscle obtained from cocaine positive forensic cases was assessed following storage at -18 degrees C for 13 months. Cocaine and benzoylecgonine (BZE) were extracted using SPE and quantified by GC-MS/MS. Cocaine was stable for 7 days in refrigerated (4 degrees C) horse blood fortified with 1 and 2% NaF. In the absence of NaF, cocaine was not detectable by day 7 in blood stored at RT and 4 degrees C and had declined by 81% following storage at -18 degrees C. At 4 degrees C the rate of cocaine degradation in blood preserved with 2% NaF was significantly slower than with 1% NaF. The stability of cocaine in horse blood appeared to be less than that reported for human blood, probably attributable to the presence of carboxylesterase in horse plasma. Cocaine stored in VH at -18 degrees C was essentially stable for the study period whereas at 4 degrees C concentrations decreased by >50% in preserved and unpreserved VH stored for longer than 14 days. Fluoride did not significantly affect cocaine stability in VH. The stability of cocaine in muscle tissue homogenates significantly exceeded that in blood and VH at every temperature. In preserved and unpreserved samples stored at 4 degrees C and below, cocaine loss did not exceed 2%. The increased stability of cocaine in muscle was attributed to the low initial pH of post-mortem muscle. In tissue from one human case stored for 13 months at -18 degrees C the muscle cocaine concentration declined by only 15% (range: 5-22%). These findings promote the use of human muscle as a toxicological specimen in which cocaine may be detected for longer compared with blood or VH. (C) 2011 Elsevier Ireland Ltd. All rights reserved.

Effects on starch and amylolytic enzymes during Lepidium meyenii Walpers root storage

The high water content in maca (Lepidium meyenii W.) roots combined with the damage produced during or after harvest makes them vulnerable to attack by enzymes and microorganisms. Although starch degradation has been extensively studied, in maca roots there is a paucity of research regarding the starch reserves. In this paper, parameters of starch degradation are shown to be related to the action of amylolytic enzymes during storage at room temperature. Over the course of three weeks, the starch and protein content, soluble sugar, total amylolytic activity, and alpha- and beta-amylase activity were measured. In addition, the integrity of starch granules was observed by scanning electron microscopy. Despite the evidence of dehydration, there were no significant differences (p <= 0.5) in the total starch content or in the activities of alpha- and beta-amylase. After the third week the roots remained suitable for consumption. The results indicate a postharvest latency that can lead to sprout or to senescence, depending on the environmental conditions. (C) 2012 Elsevier Ltd. All rights reserved.

Effects of the combination of low-level laser irradiation and recombinant human bone morphogenetic protein-2 in bone repair

Low-level laser irradiation (LLLI) and recombinant human bone morphogenetic protein type 2 (rhBMP-2) have been used to stimulate bone formation. LLLI stimulates proliferation of osteoblast precursor cells and cell differentiation and rhBMP-2 recruits osteoprogenitor cells to the bone healing area. This in vivo study evaluated the effects of LLLI and rhBMP-2 on the bone healing process in rats. Critical bone defects were created in the parietal bone in 42 animals, and the animals were divided into six treatment groups: (1) laser, (2) 7 mu g of rhBMP-2, (3) laser and 7 mu g of rhBMP-2, (4) 7 mu g of rhBMP-2/monoolein gel, (5) laser and 7 mu g rhBMP-2/monoolein gel, and (6) critical bone defect controls. A gallium-aluminum-arsenide diode laser was used (wavelength 780 nm, output power 60 mW, beam area 0.04 cm(2), irradiation time 80 s, energy density 120 J/cm(2), irradiance 1.5 W/cm(2)). After 15 days, the calvarial tissues were removed for histomorphometric analysis. Group 3 defects showed higher amounts of newly formed bone (37.89%) than the defects of all the other groups (P < 0.05). The amounts of new bone in defects of groups 1 and 4 were not significantly different from each other (24.00% and 24.75%, respectively), but were significantly different from the amounts in the other groups (P < 0.05). The amounts of new bone in the defects of groups 2 and 5 were not significantly different from each other (31.42% and 31.96%, respectively), but were significantly different from the amounts in the other groups (P < 0.05). Group 6 defects had 14.10% new bone formation, and this was significantly different from the amounts in the other groups (P < 0.05). It can be concluded that LLLI administered during surgery effectively accelerated healing of critical bone defects filled with pure rhBMP-2, achieving a better result than LLLI alone or the use of rhBMP-2 alone.

Transverse single-spin asymmetry and cross section for pi(0) and eta mesons at large Feynman x in p(up arrow) + p collisions at root s=200 GeV

Measurements of the differential cross section and the transverse single-spin asymmetry, A(N), vs x(F) for pi(0) and eta mesons are reported for 0.4 < x(F) < 0.75 at an average pseudorapidity of 3.68. A data sample of approximately 6.3 pb(-1) was analyzed, which was recorded during p(up arrow) + p collisions at root s = 200 GeV by the STAR experiment at RHIC. The average transverse beam polarization was 56%. The cross section for pi(0), including the previously unmeasured region of x(F) > 0.55, is consistent with a perturbative QCD prediction, and the eta/pi(0) cross-section ratio agrees with existing midrapidity measurements. For 0.55 < x(F) < 0.75, the average A(N) for eta is 0.210 +/- 0.056, and that for pi(0) is 0.081 +/- 0.016. The probability that these two asymmetries are equal is similar to 3%.

Interferon-gamma alters the phagocytic activity of the mouse trophoblast

Interferon-gamma (IFN-gamma) mediates diverse functions in bone marrow-derived phagocytes, including phagocytosis and microbe destruction. This cytokine has also been detected at implantation sites under both physiological and pathological conditions in many different species. At these particular sites, the outermost embryonic cell layer in close contact with the maternal tissues, the trophoblast exhibits intense phagocytic activity. To determine whether IFN-gamma affects phagocytosis of mouse-trophoblast cells, ectoplacental cone-derived trophoblast was cultured and evaluated for erythrophagocytosis. Phagocytic activity was monitored ultrastructurally and expressed as percentage of phagocytic trophoblast in total trophoblast cells. Conditioned medium from concanavalin-A-stimulated spleen cells significantly enhanced trophoblast phagocytosis. This effect was blocked by pre-incubation with an anti-IFN-gamma neutralizing antibody. Introduction of mouse recombinant IFN-gamma (mrIFN-gamma) to cultures did not increase cell death, but augmented the percentage of phagocytic cells in a dose-dependent manner. Ectoplacental cones from mice deficient for IFN-gamma receptor alpha-chain showed a significant decrease of the phagocytosis, even under mrIFN-gamma stimulation, suggesting that IFN-gamma-induced phagocytosis are receptor-mediated. Reverse transcriptase-PCR analyses confirmed the presence of mRNA for IFN-gamma receptor alpha and beta-chains in trophoblast cells and detected a significant increase in the mRNA levels of IFN-gamma receptor beta-chain, mainly, when cultured cells were exposed to IFN-gamma. Immunohistochemistry and Western blot analyses also revealed protein expression of the IFN-gamma receptor alpha-chain. These results suggest that IFN-gamma may participate in the phagocytic activation of the mouse trophoblast, albeit the exact mechanism was not hereby elucidated. Protective and/or nutritional fetal benefit may result from this physiological response. In addition, our data also shed some light on the understanding of trophoblast tolerance to inflammatory/immune cytokines during normal gestation.

Structural and vibrational study of 8-hydroxyquinoline-2-carboxaldehyde isonicotinoyl hydrazone: a potential metal-protein attenuating compound (MPAC) for the treatment of Alzheimer's disease

A comprehensive structural and vibrational study of the potential metal-protein attenuating compound 8-hydroxyquinoline-2-carboxaldehyde isonicotinoyl hydrazone is reported. X-ray diffraction data, as well as FT-IR and Raman frequencies, were compared with the respective theoretical values obtained from DFT calculations. Theory agrees well with experiment. In this context, an attempt of total assignment concerning the FT-IR and Raman spectra of the title compound was performed, shedding new light on previous partial assignments published elsewhere.

Polymer controlled mineralization of zinc phosphate hydrates and applications in corrosion protection, catalysis and biomedicine

ZUSAMMENFASSUNG Die Tauglichkeit von Hybridmaterialien auf der Basis von Zinkphosphathydrat-Zementen zum Einsatz als korrosionshemmende anorganische Pigmente oder zur prothetischen und konservierenden Knochen- und Zahntherapie wird weltweit empirisch seit den neunziger Jahren intensiv erforscht. In der vorliegenden Arbeit wurden zuerst Referenzproben, d.h. alpha-und beta-Hopeite (Abk. a-,b-ZPT) dank eines hydrothermalen Kristallisationsverfahrens in wässerigem Milieu bei 20°C und 90°C hergestellt. Die Kristallstruktur beider Polymorphe des Zinkphosphattetrahydrats Zn3(PO4)2  4 H2O wurde komplett bestimmt. Einkristall-strukturanalyse zeigt, daß der Hauptunterschied zwischen der alpha-und beta-Form des Zinkphosphattetrahydrats in zwei verschiedenen Anordnungen der Wasserstoffbrücken liegt. Die entsprechenden drei- und zweidimensionalen Anordnungen der Wasserstoffbrücken der a-und b-ZPT induzieren jeweils unterschiedliches thermisches Verhalten beim Aufwärmen. Während die alpha-Form ihr Kristallwasser in zwei definierten Stufen verliert, erzeugt die beta-Form instabile Dehydratationsprodukt. Dieses entspricht zwei unabhängigen, aber nebeneinander ablaufenden Dehydratationsmechanismen: (i) bei niedrigen Heizraten einen zweidimensionalen Johnson-Mehl-Avrami (JMA) Mechanismus auf der (011) Ebene, der einerseits bevorzugt an Kristallkanten stattfindet und anderseits von existierenden Kristalldefekten auf Oberflächen gesteuert wird; (ii) bei hohen Heizraten einem zweidimensionalen Diffusionsmechanismus (D2), der zuerst auf der (101) Ebene und dann auf der (110) Ebene erfolgt. Durch die Betrachtung der ZPT Dehydratation als irreversibele heterogene Festkörperstufenreaktion wurde dank eines „ähnlichen Endprodukt“-Protokolls das Dehydratationsphasendiagramm aufgestellt. Es beschreibt die möglichen Zusammenhänge zwischen den verschiedenen Hydratationszuständen und weist auf die Existenz eines Übergangszustandes um 170°C (d.h. Reaktion b-ZPT  a-ZPT) hin. Daneben wurde auch ein gezieltes chemisches Ätzverfahren mit verdünnten H3PO4- und NH3 Lösungen angewendet, um die ersten Stufe des Herauslösens von Zinkphosphat genau zu untersuchen. Allerdings zeigen alpha- und beta-Hopeite charakteristische hexagonale und kubische Ätzgruben, die sich unter kristallographischer Kontrolle verbreitern. Eine zuverlässige Beschreibung der Oberfächenchemie und Topologie konnte nur durch AFM und FFM Experimente erfolgen. Gleichzeitig konnte in dieser Weise die Oberflächendefektdichte und-verteilung und die Volumenauflösungsrate von a-ZPT und b-ZPT bestimmt werden. Auf einem zweiten Weg wurde eine innovative Strategie zur Herstellung von basischen Zinkphosphatpigmenten erster und zweiter Generation (d.h. NaZnPO4  1H2O und Na2ZnPO4(OH)  2H2O) mit dem Einsatz von einerseits oberflächenmodifizierten Polystyrolatices (z.B. produziert durch ein Miniemulsionspolymerisationsverfahren) und anderseits von Dendrimeren auf der Basis von Polyamidoamid (PAMAM) beschritten. Die erhaltene Zeolithstruktur (ZPO) hat in Abhängigkeit von steigendem Natrium und Wassergehalt unterschiedliche kontrollierte Morphologie: hexagonal, würfelförmig, herzförmig, sechsarmige Sterne, lanzettenförmige Dendrite, usw. Zur quantitativen Evaluierung des Polymereinbaus in der Kristallstruktur wurden carboxylierte fluoreszenzmarkierte Latices eingesetzt. Es zeigt sich, daß Polymeradditive nicht nur das Wachstum bis zu 8 µm.min-1 reduzierten. Trotzdem scheint es auch als starker Nukleationsbeschleuniger zu wirken. Dank der Koordinationschemie (d.h. Bildung eines sechszentrigen Komplexes L-COO-Zn-PO4*H2O mit Ligandenaustausch) konnten zwei einfache Mechanismen zur Wirkung von Latexpartikeln bei der ZPO Kristallisation aufgezeigt werden: (i) ein Intrakorona- und (ii) ein Extrakorona-Keimbildungsmechanismus. Weiterhin wurde die Effizienz eines Kurzzeit- und Langzeitkorrosionschutzes durch maßgeschneiderte ZPO/ZPT Pigmente und kontrollierte Freisetzung von Phosphationen in zwei Näherungen des Auslösungsgleichgewichts abgeschätzt: (i) durch eine Auswaschungs-methode (thermodynamischer Prozess) und (ii) durch eine pH-Impulsmethode (kinetischer Prozess. Besonders deutlich wird der Ausflösungs-Fällungsmechanismus (d.h. der Metamorphismus). Die wesentliche Rolle den Natriumionen bei der Korrosionshemmung wird durch ein passendes zusammensetzungsabhängiges Auflösungsmodell (ZAAM) beschrieben, das mit dem Befund des Salzsprühteste und der Feuchtigkeitskammertests konsistent ist. Schließlich zeigt diese Arbeit das herausragende Potential funktionalisierter Latices (Polymer) bei der kontrollierten Mineralisation zur Herstellung maßgeschneiderter Zinkphosphat Materialien. Solche Hybridmaterialien werden dringend in der Entwicklung umweltfreundlicher Korrosionsschutzpigmente sowie in der Dentalmedizin benötigt.