892 resultados para FREE G-ACTIONS


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Amino acids play fundamental roles in plant morphogenesis. Among sources of organic nitrogen (N), glutamine has frequently been used during the establishment and maintenance of cell and tissue cultures. The aim of this study was analyse endogenous levels of glutamine during somatic and zygotic embryogenesis of Acca sellowiana (Feijoa or pineapple guava). The in vitro absorption of H-3-labelled glutamine was investigated. Zygotic embryos and embryogenic cultures (EC) were evaluated at 30 d and 70 d after explant inoculation onto the medium. Endogenous levels of glutamine were similar during zygotic and somatic embryogenesis, and showed a gradual decline until day-24 in culture. The highest rates of H-3-labelled glutamine uptake were observed during the first 2 h of incubation, resulting in values of 6.29 mu mol g(-1) fresh weight (FW) for zygotic embryos, 14.43 mu mol g(-1) FW for EC after 30 d, and 13.85 mu mol g(-1) FW for EC after 70 d. These results showed that the decreased levels of glutamine observed during the initial phase of development may be related to de novo protein synthesis and mobilisation during embryo maturation. The absorption of glutamine in the first 2 h of incubation also emphasises its involvement as an important source of N during morphogenesis of somatic and zygotic embryos.

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The main goal of this work was to develop a simple analytical method for quantification of glycerol based on the electrocatalytic oxidation of glycerol on the copper surface adapted in a flow injection system. Under optimal experimental conditions, the peak current response increases linearly with glycerol concentration over the range 60-3200 mg kg(-1) (equivalent to 3-160 mg L(-1) in solution). The repeatability of the electrode response in the flow injection analysis (FIA) configuration was evaluated as 5% (n = 10), and the detection limit of the method was estimated to be 5 mg kg(-1) in biodiesel (equivalent to 250 mu g L(-1) in solution) (S/N = 3). The sample throughput under optimised conditions was estimated to be 90 h(-1). Different types of biodiesel samples (B100), as in the types of vegetable oils or animal fats used to produce the fuels, were analysed (seven samples). The only sample pre-treatment used was an extraction of glycerol from the biodiesel sample containing a ratio of 5 mL of water to 250 mg of biodiesel. The proposed method improves the analytical parameters obtained by other electroanalytical methods for quantification of glycerol in biodiesel samples, and its accuracy was evaluated using a spike-and-recovery assay, where all the biodiesel samples used obtained admissible values according to the Association of Official Analytical Chemists. Crown Copyright (C) 2011 Published by Elsevier Ltd. All rights reserved.

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Holsback L., Pena H.F.J., Ragozo A., Lopes E. G., Gennari S. M. & Soares R. M. 2012. Serologic and molecular diagnostic and bioassay in mice for detection of Toxoplasma gondii in free range chickens from Pantanal of Mato Grosso do Sul. Pesquisa Veterinaria Brasileira 32(8): 721-726. Setor de Veterinaria e Producao Animal, Universidade Estadual do Norte do Parana, Campus Luiz Meneghel, Rodovia BR 369 Km 54, Bandeirantes, PR 86360-000, Brazil. E-mail: lhsfertonani@uenp.edu.br The aim of this study was to investigate the occurrence of Toxoplasma gondii and compare the results obtained in the Modified Agglutination Test (MAT), Polimerase Chain Reaction (PCR) and bioassay in mice. In order to accomplish this, 40 free-range chickens from eight farms in neighboring areas to the Pantanal in Nhecolandia, Mato Grosso do Sul, were euthanized and blood samples, brain and heart were collected. The occurrence of anti-T. gondii antibodies found in chickens was 67.5% (27 samples), considering as a cutoff point the dilution 1:5. Among the samples analyzed, 7 (25.9%) were positive in the dilution 1: 5, 3 (11.1%) in 1: 10, 2 (7.4%) in 1: 20, 3 (11.1%) in 1: 320, 1 (3.7%) in 1: 640, 3 (11.1%) in 1: 1280, 2 (7.4%) in 1: 2560, 4 (14.8%) in 1: 5120 and 2 (7.4%) in 1: 10.240. From the mixture of tissue samples (brain and heart) from the chickens analyzed, 16 (40%) presented electrophoretic bands compatible with T. gondii by PCR (gene B1). In the comparison of techniques, 59.26% positivity in PCR was revealed among animals that were seropositive in MAT (cutoff 1: 5). From 141 inoculated mice, six (4.44%) died of acute toxoplasmosis between 15 and 23 days after inoculation. Surviving mice were sacrificed at 74 days after inoculation, and a total of 28 cysts were found in the brains of 10 distinct groups. From the seropositive hens, 27 bioassays were performed and 11 (40.7%) isolates were obtained. A greater number of isolations happened in mice that were inoculated with tissues from chickens that had high titers for anti-T. gondii antibodies. Chronic infection in mice was observed in nine groups (33.3%) from five different properties. Among the surviving mice, 25.6% were positive for T. gondii in MAT (1: 25). From mice positive in PCR, 87.5% were also positive in MAT. Among the PCR-negative mice, 5.2% were positive for T. gondii in MAT. It can be concluded through this study that the occurrence of infecton by T. gondii in the rural properties studied was high, that PCR directed to gene B1 does not confirm the viability of the parasite, but it can be used as a screening method for the selection of chickens infected by T. gondii, that the animals with titer greater than 10 must be prioritized for the selection of animals for bioassay, since for them, the chances of isolating the parasite are greater and that seroconversion in experimentally infected mice is not a good indicator for isolating the agent.

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Mini-implant insertion requires accurate surgical technique. This study shows an insertion technique using only tooth crown references; its scientific basis is evaluated radiographically. The sample consisted of 213 inter-radicular septa, evaluated in 53 bitewing radiographs. The proximal contour of adjacent tooth crowns was used to define septum width. The midpoint of the septum width was linked to the interdental contact point to determine septum midline. The distances from septum midline to "mesial and distal teeth were measured to evaluate the septum midline centralization degree in two different septum heights. The difference between mesial and distal distances represented the septum midline deviation degree. The mesial and distal distances were compared by t-tests, and the septum midline deviation was correlated with septum height using Pearson's correlation test. The mesial and distal distances were not statistically different in the midpoint of the septum height, but they were different at the apical septum height. There was a moderate correlation (r = 0.45) between septum midline deviation and septum height. The tooth crown references evaluated on interproximal radiographs determine a high centralization degree of the septum midline on which the insertion site could be defined. The greater centralization degree was observed at the coronal septum area.

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Humicola brevis var. thermoidea cultivated under solid state fermentation in wheat bran and water (1:2 w/v) was a good producer of beta-glucosidase and xylanase. After optimization using response surface methodology the level of xylanase reached 5,791.2 +/- A 411.2 U g(-1), while beta-glucosidase production was increased about 2.6-fold, reaching 20.7 +/- A 1.5 U g(-1). Cellulase levels were negligible. Biochemical characterization of H. brevis beta-glucosidase and xylanase activities showed that they were stable in a wide pH range. Optimum pH for beta-glucosidase and xylanase activities were 5.0 and 5.5, respectively, but the xylanase showed 80 % of maximal activity when assayed at pH 8.0. Both enzymes presented high thermal stability. The beta-glucosidase maintained about 95 % of its activity after 26 h in water at 55 A degrees C, with half-lives of 15.7 h at 60 A degrees C and 5.1 h at 65 A degrees C. The presence of xylose during heat treatment at 65 A degrees C protected beta-glucosidase against thermal inactivation. Xylanase maintained about 80 % of its activity after 200 h in water at 60 A degrees C. Xylose stimulated beta-glucosidase activity up to 1.7-fold, at 200 mmol L-1. The notable features of both xylanase and beta-glucosidase suggest that H. brevis crude culture extract may be useful to compose efficient enzymatic cocktails for lignocellulosic materials treatment or paper pulp biobleaching.

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Prevalence of Toxoplasma gondii infection in 510 free-range (FR) chickens (380 from 33 small farms, and 130 from a slaughter house for FR chickens) from Espirito Santo state, southeastern Brazil, was investigated. Antibodies to T. gondii were sought using commercial indirect haemagglutination (IHAT, Imuno-HAI Toxo (R), Wama Diagnostica, Sao Paulo, Brazil, cut-off 1:16) and the modified agglutination test (MAT, cut-off 1:25) tests. Attempts were made to isolate viable T. gondii from seropositive chickens by bioassay in mice. Pooled samples of brain, heart and quadriceps muscle of one thigh (total 40 g) from 64 chickens with IHAT titers of >= 1:16 were minced, digested in pepsin and bioassayed in mice. Antibodies to T. gondii were found in 40.4% (206/510) FR chickens by IHAT (titer >= 1:16) and 38.8% (198/510) by MAT (titer >= 1:25); concordance between IHAT and MAT was 81.6% (kappa index = 0.614). Viable T. gondii was isolated (designated TgCkBr234-281) from 48 of 64(75%) seropositive (IHAT titers >= 1:32) FR chickens. Most isolates of T. gondii were virulent for mice; 100% of mice inoculated with 44 of 48 isolates died of toxoplasmosis within 30 days post inoculation (p.i). An epidemiological investigation revealed that people living in rural areas have little knowledge about the parasite and about the risk of acquiring it from raw meat. Results indicated that the locally available IHAT was useful for screening of chicken sera for T. gondii antibodies. (C) 2012 Elsevier B.V. All rights reserved.

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Full validation of the electrochemical mechanisms so far postulated as driving force of electric field-assisted non-spontaneous crystallization development in given glasses has suffered experimental restrictions. In this work, we looked into origin of this phenomenon in lead oxyfluoroborate glasses, resulting in beta-PbF2 growth even below the corresponding glass transition temperatures, through achieving a systematic study of not only Pt,Ag/Glass/Ag,Pt- but also Pt,Ag/Glass/YSZ:PbF2/Ag,Pt-type cells, where YSZ:PbF2 represents a two-phase system (formed by Y2O3-doped ZrO2 and PbF2). It is demonstrated that crystallization induction in these glasses involves Pb2+ ions reduction at the cathode, the phenomenon being, however, confirmed only when the F- ions were simultaneously also able to reach the anode for oxidation, after assuring either a direct glass-anode contact or percolation pathways for free fluoride migration across the YSZ:PbF2 mixtures. A further support of this account is that the electrochemically induced beta-PbF2 phase crystallizes showing ramified-like microstructure morphology that arises, accordingly, from development of electroconvective diffusion processes under electric field action.

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Background: Since noradrenergic innervation was described in the ovarian follicle, the actions of the intraovarian catecholaminergic system have been the focus of a variety of studies. We aimed to determine the gonadotropin-independent effects of the catecholamine norepinephrine (NE) in the steroid hormone profile of a serum-free granulosa cell (GC) culture system in the context of follicular development and dominance. Methods: Primary bovine GCs were cultivated in a serum-free, chemically defined culture system supplemented with 0.1% polyvinyl alcohol. The culture features were assessed by hormone measurements and ultrastructural characteristics of GCs. Results: GCs produced increasing amounts of estradiol and pregnenolone for 144h and maintained ultrastructural features of healthy steroidogenic cells. Progesterone production was also detected, although it significantly increased only after 96h of culture. There was a highly significant positive correlation between estradiol and pregnenolone production in high E2-producing cultures. The effects of NE were further evaluated in a dose response study. The highest tested concentration of NE (10 (-7) M) resulted in a significant increase in progesterone production, but not in estradiol or pregnenolone production. The specificity of NE effects on progesterone productio n was further investigated by incubating GCs with propranolol (10 (-8) M), a non-selective beta-adrenergic antagonist. Conclusions: The present culture system represents a robust model to study the impact of intrafollicular factors, such as catecholamines, in ovarian steroidogenesis and follicular development. The results of noradrenergic effects in the steroidogenesis of GC have implications on physiological follicular fate and on certain pathological ovarian conditions such as cyst formation and anovulation.

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This paper is a continuation of Dokuchaev and Novikov (2010) [8]. The interaction between partial projective representations and twisted partial actions of groups considered in Dokuchaev and Novikov (2010) [8] is treated now in a categorical language. In the case of a finite group G, a structural result on the domains of factor sets of partial projective representations of G is obtained in terms of elementary partial actions. For arbitrary G we study the component pM'(G) of totally-defined factor sets in the partial Schur multiplier pM(G) using the structure of Exel's semigroup. A complete characterization of the elements of pM'(G) is obtained for algebraically closed fields. (C) 2011 Elsevier B.V. All rights reserved.

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Abstract Background Hemophilia A is a bleeding disorder caused by deficiency in coagulation factor VIII. Recombinant factor VIII (rFVIII) is an alternative to plasma-derived FVIII for the treatment of hemophilia A. However, commercial manufacturing of rFVIII products is inefficient and costly and is associated to high prices and product shortage, even in economically privileged countries. This situation may be solved by adopting more efficient production methods. Here, we evaluated the potential of transient transfection in producing rFVIII in serum-free suspension HEK 293 cell cultures and investigated the effects of different DNA concentration (0.4, 0.6 and 0.8 μg/106 cells) and repeated transfections done at 34° and 37°C. Results We observed a decrease in cell growth when high DNA concentrations were used, but no significant differences in transfection efficiency and in the biological activity of the rFVIII were noticed. The best condition for rFVIII production was obtained with repeated transfections at 34°C using 0.4 μg DNA/106 cells through which almost 50 IU of active rFVIII was produced six days post-transfection. Conclusion Serum-free suspension transient transfection is thus a viable option for high-yield-rFVIII production. Work is in progress to further optimize the process and validate its scalability.

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The pulmonary crackling and the formation of liquid bridges are problems that for centuries have been attracting the attention of scientists. In order to study these phenomena, it was developed a canonical cubic lattice-gas­ like model to explain the rupture of liquid bridges in lung airways [A. Alencar et al., 2006, PRE]. Here, we further develop this model and add entropy analysis to study thermodynamic properties, such as free energy and force. The simulations were performed using the Monte Carlo method with Metropolis algorithm. The exchange between gas and liquid particles were performed randomly according to the Kawasaki dynamics and weighted by the Boltzmann factor. Each particle, which can be solid (s), liquid (l) or gas (g), has 26 neighbors: 6 + 12 + 8, with distances 1, √2 and √3, respectively. The energy of a lattice's site m is calculated by the following expression: Em = ∑k=126 Ji(m)j(k) in witch (i, j) = g, l or s. Specifically, it was studied the surface free energy of the liquid bridge, trapped between two planes, when its height is changed. For that, was considered two methods. First, just the internal energy was calculated. Then was considered the entropy. It was fond no difference in the surface free energy between this two methods. We calculate the liquid bridge force between the two planes using the numerical surface free energy. This force is strong for small height, and decreases as the distance between the two planes, height, is increased. The liquid-gas system was also characterized studying the variation of internal energy and heat capacity with the temperature. For that, was performed simulation with the same proportion of liquid and gas particle, but different lattice size. The scale of the liquid-gas system was also studied, for low temperature, using different values to the interaction Jij.

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Oxidative stress is considered to be of major relevance for a variety of pathological processes. Thus, it is valuable to identify compounds, which might act as antioxidants, i.e. compounds that antagonize the deleterious action of reactive oxygen species (ROS) on biomolecules. The mode of action of these compounds could be either to scavenge ROS directly or to trigger protective mechanisms inside the cell, thereby resulting in improved defense against ROS. Sulforaphane (SF) (1-isothiocyanato-(4R)-(methylsulfinyl)butane) is a naturally occurring cancer chemopreventive agent found as a precursor glucosinolate in Cruciferous vegetables like broccoli. Although SF is not a direct-acting antioxidant, there is substantial evidence that SF acts indirectly to increase the antioxidant capacity of animal cells and their abilities to cope with oxidative stress. Induction of phase 2 enzymes is one means by which SF enhances the cellular antioxidant capacity. Enzymes induced by SF include Glutathione S-transferases (GST) and NAD[P]H:quinone oxidoreductase (NQO1) which can function as protectors against oxidative stress. To protect themselves from oxidative stress, cells are equipped with reducing buffer systems including the GSH and thioredoxin (Trx) reductase. GSH is an important tripeptide thiol which in addition to being the substrate for GSTs maintains the cellular oxidation– reduction balance and protects cells against free radical species. Aim of the first part of this thesis was to investigate the ability of SF to induce the expression and the activity of different phase 2 and antioxidant enzymes (such as GST, GR, GPx, NQO1, TR, SOD, CAT) in an in vitro model of rat cardiomyocytes, and also to define if SF treatment supprts cells in counteracting oxidative stress induced by H2O2 It is well known that acute exhaustive exercise causes significant reactive oxygen species generation that results in oxidative stress, which can induce negative effects on health and well being. In fact, increased oxidative stress and biomarkers (e.g., protein carbonyls, MDA, and 8- hydroxyguanosine) as well as muscle damage biomarkers (e.g. plasmatic Creatine cinase and Lactate dehydrogenase) have been observed after supramaximal sprint exercises, exhaustive longdistance cycling or running as well as resistance-type exercises, both in trained and untrained humans. Markers of oxidative stress also increase in rodents following exhaustive exercise. Moreover, antioxidant enzyme activities and expressions of antioxidant enzymes are known to increase in response to exhaustive exercise in both animal and human tissues. Aim of this project was to evaluate the effect of SF supplementation in counteracting oxidative stress induced by physical activity through its ability to induce phase 2, and antioxidant enzymes in rat muscle. The results show that SF is a nutraceutical compound able to induce the activity of different phase 2 and antioxidant enzymes in both cardiac muscle and skeletal muscle. Thanks to its actions SF is becoming a promising molecule able to prevent cardiovascular damages induced by oxidative stress and muscle damages induced by acute exhaustive exercise.

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Zusammenfassung Die vorliegenden Arbeit beschäftigt sich mit den Synthesen und Charakterisierungen multifunktioneller, Arylamin-haltiger Polymere, welche sich als photorefraktive(PR)-Materialien eignen. Die Glastemperaturen (Tg) der angestrebten Materialien liegen deutlich über Raumtemperatur, um so den Pockels-Mechanismus zum Aufbau des PR-Effektes zu favorisieren. Hierzu sind zwei synthetische Konzepte, basierend auf Maleinimid-Methylvinylisocyanat-Reaktiv-Polymeren und Triphenylamin-haltigen Polymeren, entwickelt worden. Im Rahmen des Reaktiv-Polymer-Konzeptes konnten PR-Materialien mit den bisher größten Beugungs-Effizienzen sowie den schnellsten Ansprechzeiten für multifunktionelle hoch-Tg-Polymere dargestellt werden. Hierfür wurden Maleinimid-Methylvinylisocyanat-Reaktiv-Polymere synthetisiert welche an der Imid-Position über Spacer-Gruppen mit Carbazol-Einheiten funktionalisiert sind. Die Tg´s der Polymere konnten zwischen 60°C und 194°C eingestellt werden. Die Isocyanat-Gruppen wurden dann polymeranlog mit hydroxyalkyl-funktionalisierten Chromophoren umgesetzt. Die Kinetik des PR-Effektes dieser Materialien wird durch die Ladungsträger-Beweglichkeiten in den Proben bestimmt. Eine Steigerung der Farbstoff-Konzentrationen erhöht die PR-Leistungen der Materialien, behindert jedoch deren Kinetik.Das Triphenylamin-Polymer-Konzept verwendet Triphenylamine als Lochleiter. Hierfür wurden die radikalischen Polymerisations-Verhalten der Monomere p-Diphenylaminostyrol (DPAS) und erstmals p-Ditoluylaminostyrol (DTAS) untersucht. Die Monomere wurden durch spontane, freie und kontrollierte radikalische Verfahren polymerisiert. Mittels eines TEMPO-Derivates gelang der Aufbau von Block-Copolymeren. Poly-DPAS konnte, im Gegensatz zu Poly-DTAS, polymeranlog tricyanovinyliert werden. Dadurch lassen sich PDPAS-block-PTPAS-Copolymere selektiv im PDPAS-Block tricyanovinylieren. Diese Materialien weisen eine Tendenzen zur Mikro-Phasen-Separation auf.Die Strukturierung von PDPAS konnte durch Photo-Polymerisation mit einer Auflösung von wenigen mm demonstriert werden. Carbazol und Triphenylamin-haltige Materialien wurden mittels Cyclo-Voltametrie untersucht.

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In der Überprüfung von Kernmodellen stellt der elektrische Formfaktor des Neutrons Gen eine wichtige Eingangsgröße dar. Im Rahmen dieser Arbeit wurde am polarisierten Elektronenstrahl des Mainzer Mikrotrons MAMI der elektrische Formfaktor des Neutrons in der Reaktion 3He(e,e'n) bestimmt. Aus dem Verhältnis der Asymmetrien respektive der Helizitätsumkehr der Elektronenpolarisation mit Targetspin senkrecht und parallel zum Impulsübertrag konnte in einer integralen Analyse Gen bestimmt werden. Zusammengefasst ergab sich Gen(Q2=0.67 (GeV/c)2) = 0.0468 +- 0.0064(stat} +- 0.0027(syst}. Um den Einfluß von Kernbindungseffekten, die z. Zt. von der Gruppe um Prof. Glöckle in Bochum theoretisch gerechnet werden, auch experimentell abzusichern, wurden parallel zur Gen-Messung die Targetasymmetrie Ay0 3He(e,e'n) und Protonenasymmetrie 3He(e,e'p) bestimmt. Die Empfindlichkeit dieser Observablen auf FSI und D-Wellenbeiträge schafft Redundanzen, aus denen auf die Eigenschaften des freien Neutrons im gebundenen System geschlossen werden kann.

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Die differentielle Hyperfeinanomalie beschreibt den Isotopieeffekt der magnetischen Hyperfeinwechselwirkung und stellt eine Testmöglichkeit für Kernmodelle dar. Nachdem in einer Reihe von Messungen die A-Faktoren der Hyperfeinwechselwirkung im Grundzustand von zwei stabilen und fünf instabilen Europium-Isotopen bestimmt wurden, sollen nun die Kern-g-Faktoren der gleichen Isotope bestimmt werden.Um die Kern-g-Faktoren zu bestimmen, wurden zunächst die Termschemata des Grundzustandesder stabilen Isotope 151,153Eu+ simuliert. Wegen der hohen Kern- und Hüllenspins I=5/2, J=4 ergeben sich 54 Zeemanzustände und ein komplexes optisches Spektrum.Etwa 10^6 Ionen der beiden stabilen Isotope 151,153Eu+ werden in einer Penningfalle beieinem Magnetfeld von ca. 1.5T gespeichert. Durch Puffergas und Anregung einer Seitenbandfrequenzder Ionenbewegung wird optisches Pumpen in metastabile D-Zustände bei gleichzeitiger Kühlung der Ionenwolke verhindert.Bei Verstimmung eines frequenzverdoppelten Ti:Sa-Lasers wurde die Ionenfluoreszenz aufgenommen. Durch die Simulation der optischen Spektren gelang es, einzelne Übergänge des Isotopes 151Eu+ zu identifizieren. Mit Laser/Mikrowellen-Doppelresonanzmessungen erhält man ein in erster Ordnung dopplerfreies Mikrowellenspektren eines Überganges zwischen zwei Zeemanzuständen im Grundzustand.Durch Messung der Übergangsfrequenzen von insgesamt fünf Delta mI=+1 Übergängen und Bestimmung des Magnetfeldes durch Messung der Zyklotronfrequenz gespeicherter Elektronen konnte der gI-Faktor des Isotopes151Eu zu 151gI = 1.37734(6) bestimmt werden.