980 resultados para Addition of lime
Resumo:
The research performed during the PhD candidature was intended to evaluate the quality of white wines, as a function of the reduction in SO2 use during the first steps of the winemaking process. In order to investigate the mechanism and intensity of interactions occurring between lysozyme and the principal macro-components of musts and wines, a series of experiments on model wine solutions were undertaken, focusing attention on the polyphenols, SO2, oenological tannins, pectines, ethanol, and sugar components. In the second part of this research program, a series of conventional sulphite added vinifications were compared to vinifications in which sulphur dioxide was replaced by lysozyme and consequently define potential winemaking protocols suitable for the production of SO2-free wines. To reach the final goal, the technological performance of two selected yeast strains with a low aptitude to produce SO2 during fermentation were also evaluated. The data obtained suggested that the addition of lysozyme and oenological tannins during the alcoholic fermentation could represent a promising alternative to the use of sulphur dioxide and a reliable starting point for the production of SO2-free wines. The different vinification protocols studied influenced the composition of the volatile profile in wines at the end of the alcoholic fermentation, especially with regards to alcohols and ethyl esters also a consequence of the yeast’s response to the presence or absence of sulphites during fermentation, contributing in different ways to the sensory profiles of wines. In fact, the aminoacids analysis showed that lysozyme can affect the consumption of nitrogen as a function of the yeast strain used in fermentation. During the bottle storage, the evolution of volatile compounds is affected by the presence of SO2 and oenological tannins, confirming their positive role in scaveging oxygen and maintaining the amounts of esters over certain levels, avoiding a decline in the wine’s quality. Even though a natural decrease was found on phenolic profiles due to oxidation effects caused by the presence of oxygen dissolved in the medium during the storage period, the presence of SO2 together with tannins contrasted the decay of phenolic content at the end of the fermentation. Tannins also showed a central role in preserving the polyphenolic profile of wines during the storage period, confirming their antioxidant property, acting as reductants. Our study focused on the fundamental chemistry relevant to the oxidative phenolic spoilage of white wines has demonstrated the suitability of glutathione to inhibit the production of yellow xanthylium cation pigments generated from flavanols and glyoxylic acid at the concentration that it typically exists in wine. The ability of glutathione to bind glyoxylic acid rather than acetaldehyde may enable glutathione to be used as a ‘switch’ for glyoxylic acid-induced polymerisation mechanisms, as opposed to the equivalent acetaldehyde polymerisation, in processes such as microoxidation. Further research is required to assess the ability of glutathione to prevent xanthylium cation production during the in-situ production of glyoxylic acid and in the presence of sulphur dioxide.
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Peptide receptor targeting has become an increasingly attractive method to target tumors diagnostically and radiotherapeutically. Peptides linked to a variety of chelators have been developed for this purpose. They have, however, rarely been tested for their agonistic or antagonistic properties. We report here on a somatostatin antagonist that switched to an agonist upon coupling to a DOTA chelator.
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The addition of a ZnS shell to CdSe and CdS quantum dot cores was explored using various methods. Spectrophotometry was used to assess the success of ZnS overcoating, which produces both an increase in overall fluorescence and decrease in particle size distribution. A new method was developed, involving preheating of the zinc and sulfide precursor solutions, resulting in CdSe(ZnS) particles with improved fluorescence and a more uniform shell coating from oleylamine-capped CdSe core particles.
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The synthesis and the photophysical properties of the complex [Ru(TTF-dppz)(2)(Aqphen)](2+) (TTF = tetrathiafulvalene, dppz = dipyrido-[3,2-a:2',3'-c]phenazine, Aqphen = anthraquinone fused to phenanthroline via a pyrazine bridge) are described. In this molecular triad excitation into the metal ligand charge transfer bands results in the creation of a long-lived charge separated state with TTF acting as electron donor and anthraquinone as terminal acceptor. The lifetime of the charge-separated state is 400 ns in dichloromethane at room temperature. A mechanism for the charge separation involving an intermediate charge-separated state is proposed based on transient absorption spectroscopy.
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An urgent need for new treatment modalities is emerging in elderly patients with acute myeloid leukemia (AML). We hypothesized that targeting VEGF might furnish an effective treatment modality in this population. Elderly patients with AML were randomly assigned in this phase 2 study (n = 171) to receive standard chemotherapy (3 + 7) with or without bevacizumab at a dose of 10 mg/kg intravenously at days 1 and 15. In the second cycle, patients received cytarabine 1000 mg/m(2) twice daily on days 1-6 with or without bevacizumab. The complete remission rates in the 2 arms were not different (65%). Event-free survival at 12 months was 33% for the standard arm versus 30% for the bevacizumab arm; at 24 months, it was 22% and 16%, respectively (P = .42). The frequencies of severe adverse events (SAEs) were higher in the bevacizumab arm (n = 63) compared with the control arm (n = 28; P = .043), but the percentages of death or life-threatening SAEs were lower in the bevacizumab arm (60% vs 75% of SAEs). The results of the present study show that the addition of bevacizumab to standard chemotherapy does not improve the therapeutic outcome of older AML patients. This trial is registered as number NTR904 in The Nederlands Trial Register (www.trialregister.nl).
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Fluconazole is effective in the therapy of cryptococcal meningitis in patients with AIDS. The optimal dosage of fluconazole and the impact of combination with flucytosine are not known. In this study, rabbits with experimental cryptococcal meningitis were given fluconazole at low, intermediate, or high dose or in combination with a low or intermediate dose of flucytosine. Serial cerebrospinal fluid (CSF) examinations showed that all three doses of fluconazole and low-dose fluconazole in combination with intermediate-dose flucytosine were effective in reducing CSF cryptococcal titer, lactate, white blood cell count, and cryptococcal antigen (CRAG) titers. The intermediate and high doses of fluconazole reduced CSF fungal (P < .05) and CRAG (P < .001) titers earlier than low-dose fluconazole alone or in combination with flucytosine. Only the highest dose of fluconazole reduced brain edema after 7 days. In this model of cryptococcal meningitis, there was evidence of a dose response with fluconazole but no in vivo synergism with flucytosine.
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Since the advent of automobiles, alcohol has been considered a possible engine fuel1,2. With the recent increased concern about the high price of crude oil due to fluctuating supply and demand and environmental issues, interest in alcohol based fuels has increased2,3. However, using pure alcohols or blends with conventional fuels in high percentages requires changes to the engine and fuel system design2. This leads to the need for a simple and accurate conventional fuels-alcohol blends combustion models that can be used in developing parametric burn rate and knock combustion models for designing more efficient Spark Ignited (SI) engines. To contribute to this understanding, numerical simulations were performed to obtain detailed characteristics of Gasoline-Ethanol blends with respect to Laminar Flame Speed (LFS), autoignition and Flame-Wall interactions. The one-dimensional premixed flame code CHEMKIN® was applied to simulate the burning velocity and autoignition characteristics using the freely propagating model and closed homogeneous reactor model respectively. Computational Fluid Dynamics (CFD) was used to obtain detailed flow, temperature, and species fields for Flame-wall interactions. A semi-detailed validated chemical kinetic model for a gasoline surrogate fuel developed by Andrae and Head4 was used for the study of LFS and Autoignition. For the quenching study, a skeletal chemical kinetic mechanism of gasoline surrogate, having 50 species and 174 reactions was used. The surrogate fuel was defined as a mixture of pure n-heptane, isooctane, and toluene. For LFS study, the ethanol volume fraction was varied from 0 to 85%, initial pressure from 4 to 8 bar, initial temperature from 300 to 900K, and dilution from 0 to 32%. Whereas for Autoignition study, the ethanol volume fraction was varied between 0 to 85%, initial pressure was varied between 20 to 60 bar, initial temperature was varied between 800 to 1200K, and the dilution was varied between 0 to 32% at equivalence ratios of 0.5, 1.0 and 1.5 to represent the in-cylinder conditions of a SI engine. For quenching study three Ethanol blends, namely E0, E25 and E85 are described in detail at an initial pressure of 8 atm and 17 atm. Initial wall temperature was taken to be 400 K. Quenching thicknesses and heat fluxes to the wall were computed. The laminar flame speed was found to increase with ethanol concentration and temperature but decrease with pressure and dilution. The autoignition time was found to increase with ethanol concentration at lower temperatures but was found to decrease marginally at higher temperatures. The autoignition time was also found to decrease with pressure and equivalence ratio but increase with dilution. The average quenching thickness was found to decrease with an increase in Ethanol concentration in the blend. Heat flux to the wall increased with increase in ethanol percentage in the blend and at higher initial pressures. Whereas the wall heat flux decreased with an increase in dilution. Unburned Hydrocarbon (UHC) and CO % was also found to decrease with ethanol concentration in the blend.
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OBJECTIVE: Contact of blood with artificial surfaces and air as well as ischemia/reperfusion injury to the heart and lungs mediate systemic and local inflammation during cardiopulmonary bypass (CPB). Activation of complement and coagulation cascades leads to and accompanies endothelial cell damage. Therefore, endothelial-targeted cytoprotection with the complement inhibitor and endothelial protectant dextran sulfate (DXS, MW 5000) may attenuate CBP-associated myocardial and pulmonary injury. METHODS: Eighteen pigs (DXS, n=10; phosphate buffered saline [PBS], n=8) underwent standard cardiopulmonary bypass. After aortic cross-clamping, cardiac arrest was initiated with modified Buckberg blood cardioplegia (BCP), repeated after 30 and 60 min with BCP containing either DXS (300 mg/10 ml, equivalent to 5mg/kg) or 10 ml of PBS. Following 30 min reperfusion, pigs were weaned from CPB. During 2h of observation, cardiac function was monitored by echocardiography and invasive pressure measurements. Inflammatory and coagulation markers were assessed regularly. Animals were then sacrificed and heart and lungs analyzed. RESULTS: DXS significantly reduced CK-MB levels (43.4+/-14.8 ng/ml PBS, 35.9+/-11.1 ng/ml DXS, p=0.042) and significantly diminished cytokine release: TNFalpha (1507.6+/-269.2 pg/ml PBS, 222.1+/-125.6 pg/ml DXS, p=0.0071), IL1beta (1081.8+/-203.0 pg/ml PBS, 110.7+/-79.4 pg/ml DXS, p=0.0071), IL-6 (173.0+/-91.5 pg/ml PBS, 40.8+/-19.4 pg/ml DXS, p=0.002) and IL-8 (304.6+/-81.3 pg/ml PBS, 25.4+/-14.2 pg/ml DXS, p=0.0071). Tissue endothelin-1 levels were significantly reduced (6.29+/-1.90 pg/100mg PBS, 3.55+/-1.15 pg/100mg DXS p=0.030) as well as thrombin-anti-thrombin formation (20.7+/-1.0 microg/ml PBS, 12.8+/-4.1 microg/ml DXS, p=0.043). Also DXS reduced cardiac and pulmonary complement deposition, neutrophil infiltration, hemorrhage and pulmonary edema (measured as lung water content, 81+/-3% vs 78+/-3%, p=0.047), indicative of attenuated myocardial and pulmonary CPB-injury. Diastolic left ventricular function (measured as dp/dt(min)), pulmonary artery pressure (21+/-3 mmHg PBS, 19+/-3 mmHg DXS, p=0.002) and right ventricular pressure (21+/-1 mmHg PBS, 19+/-3 mmHg DXS p=0.021) were significantly improved with the use of DXS. CONCLUSIONS: Addition of DXS to the BCP solution ameliorates post-CPB injury and to a certain extent improves cardiopulmonary function. Endothelial protection in addition to myocyte protection may improve post-CPB outcome and recovery.
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An amalgam is an alloy of mercury with other metals, and amalgamation is the art of making or forming amalgams. In metallurgical language the word is limited to the means adopted for the recovery of gold and silver from their ores by the use of mercury.
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From the standpoint of its practical usefulness, the most important characteristics of metallic lead are its cheapness, resistance to corrosion, plasticity, high specific gravity, low melting point, and its ability to form alloys in which some properties are modified by the addition of other elements, while other properties remain the same.
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We examined the cerebrospinal fluid penetration of daptomycin after the addition of dexamethasone and its bactericidal efficacy with and without ceftriaxone in an experimental rabbit model of pneumococcal meningitis. The combination of daptomycin with ceftriaxone was the most efficacious regimen for pneumococcal meningitis. The previous addition of dexamethasone affected the antibacterial activity of daptomycin only marginally, either as monotherapy or combined with ceftriaxone, although the penetration of daptomycin into inflamed meninges was significantly reduced from 6 to 2%. Daptomycin with ceftriaxone might be a potential candidate for the empirical therapy of bacterial meningitis, although the activity of this regimen against Listeria monocytogenes remains to be demonstrated.
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An efficient aza-Michael addition of amines to a series of ,-unsaturated ketones, carboxylic esters, nitriles and chalcones has been carried out using perchloric acid supported over silica gel (HClO4-SiO2) at room temperature in high yields under solvent-free reaction conditions.
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Background: Receptor Activator of Nuclear Factor kappaB Ligand (RANKL), a member of the TNF superfamily, contributes to the imbalance of bone resorption and immunoregulation in rheumatoid arthritis. In mice, collagen induced arthritis was exacerbated by IL-3 and anti-IgER antibodies, two mediators activating basophils that are known as effector cells of allergy. Interestingly, our unpublished microarray data revealed that IL-3 induces RANKL mRNA in human basophils. Here we further investigate under which conditions human basophils express surface and/or soluble RANKL. Methods: One part of purified human basophils was co-stimulated with IL-3 and either IgE-dependent or IgE-independent stimuli. The other part of purified basophils was first primed with IL-3 and subsequently triggered with IgE-dependent or IgE-independent stimuli. Expression of surface and soluble RANKL were detected by flow cytometry, ELISA and real-time PCR. Results: By flow cytometry we show that IL-3 induces de novo expression of surface RANKL on human basophils in a time and dose dependent manner. Co-stimulation of basophils with IL-3 and an IgE-dependent stimulus reduces IL-3-induced expression of surface RANKL in a dose dependent manner while IgE-independent stimuli have no effect. In contrast, both IgE-dependent and IgE-independent stimuli enhance expression of surface and soluble RANKL in basophils that were first primed with IL-3 and then triggered. Real-time PCR analysis shows that surface hRANKL1 and soluble hRANKL3 are induced by IL-3 and reduced by co-stimulation with IL-3 and an IgE-dependent stimulus and thus confirms our flow cytometry data. Conclusion: RANKL expression in human basophils is not only dependent on IL-3 and IgE-dependent/IgE-independent stimuli but also on the sequence of their addition to cell culture. Based on our data, we suggest that basophils might have previously unidentified functions in bone resorption or immunoregulation via RANKL.