944 resultados para O-2 REDUCTION


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The influences of HCl, HNO3 and HF treatments of carbon on N2O and NO reduction with 20 wt% Cu-loaded activated carbon were studied. The order of activity in both N2O and NO is as follows: Cu20/AC-HNO3>Cu20/AC>Cu20/AC-HF>Cu20/AC-HCl. The same sequence was also observed for the amount of CO2 evolved during TPD experiments of supports acid for the catalyst dispersion. On the other hand, N2O exhibited a higher reaction rate than NO and a higher sensitivity to acid treatments, and the presence of gas-phase O-2 had opposite effects in N2O and NO reduction. The key role of carbon surface chemistry is examined to rationalize these findings and the relevant mechanistic and practical implications are discussed. The effects of oxygen surface groups on the pore structure of supports and catalysts are also analyzed, (C) 2000 Elsevier Science Ltd. All rights reserved.

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Previous experimental studies showed that the presence of O-2 greatly enhances NO-carbon reaction while it depresses N2O-carbon reaction on carbon surfaces. A popular explanation for the rate increase is that the addition of O-2 results in a large number of reactive carbon-oxygen complexes, and decomposition of these complexes produces many more active sites. The explanation for the latter is that excess O-2 simply blocks the active sites, thus reducing the rate of N2O-carbon reaction. The contradiction is that O-2 can also occupy active sites in NO-carbon reaction and produce active sites in N2O-carbon reduction. By using ab initio calculation, we find that the opposite roles of O-2 are caused by the different manners of N2O and NO adsorption on the carbon surface. In the presence of excess O-2, most Of the active sites are occupied by oxygen groups. In the competition for the remaining active sites, NO is more likely to chemisorb in the form of NO2 and NO chemisorption is mon thermodynamically favorable than O-2 chemisorption. By contrast, the presence of excess O-2 makes N2O chemisorption much less thermally stable either on the consecutive edge sites or edge sites isolated by semiquinone oxygen. A detailed analysis and discussion of the reaction mechanism of N-2 formation from NO- and N2O-carbon reaction in the presence of O-2 is presented in this paper.

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Hepatitis C virus (HCV) is a major cause of chronic liver disease that may progress to cirrhosis. Antiviral treatment is successful in less than 50% of patients, is costly and causes debilitating side effects. For these reasons, additional therapies to limit the progression of liver disease are urgently required. Steatosis is found in 60% of patients with HCV and is strongly associated with more severe fibrosis. Improvements in biochemical parameters may be seen with weight reduction, however the effects on liver histology have not been investigated. We propose that in patients with chronic HCV and steatosis, obesity contributes to fat in the liver, which results in increased fibrosis and progression to cirrhosis. This study investigated the effect of weight reduction on liver biochemistry and histology in patients with HCV and the success of weight maintenance after an intensive intervention. We examined the effect of a 12 week diet and exercise program where all subjects were seen weekly by the Dietician, with the goal of achieving a 0.5 kg weight loss per week. Biochemistry was monitored monthly and a liver biopsy was performed prior to and 3-6 months after the intervention period. Patients then entered a 12 month weight maintenance program with monthly dietetic review. After 12 weeks there was a mean weight loss of 5.9 ± 3.2 kg and a mean reduction in waist circumference of 9.0 ± 5.0 cm. In 16 of the 19 patients, serum ALT levels fell progressively with weight loss. Mean fasting insulin fell from 16 to 11 mmol/L (p

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Steatosis occurs in >50% of patients with chronic HCV. In patients with viral genotype 3, steatosis may be a cytopathic effect of the virus. However in many patients with HCV, the pathogenesis of steatosis appears to be the same as for patients with non-alcoholic fatty liver disease (NAFLD) ie related to increased body mass index (BMI). We studied the effect of a 12 week weight reduction program on metabolic parameters in subjects with chronic HCV genotype 1 (Group 1, n = 16), genotype 3 (Group 2, n = 13) and patients with NAFLD (Group 3, n = 13). A liver biopsy was performed prior to and 3-6 months after the intervention period in 15 patients. The mean (SD) BMI of subjects in groups 1, 2 and 3 was 30.7 (4.0), 29.0 (5.2) and 33.3 (7.7), respectively. There was no significant difference in the amount of weight loss, change in waist circumference, change in ALT or reduction in steatosis between the 3 groups. Mean (SD) weight loss was 5.1 (3.7) kg. In those patients who lost weight, serum insulin (mean (SD) mU/L) changed from 17.8 (7.8) to 11.5 (4.8) (p = 0.003), 12.4 (5.0) to 8.4 (4.3) (p = 0.02), and 16.9 (7.3) to 17.8 (8.1) (p = 0.76) in Groups 1, 2 and 3, respectively. A small amount of weight loss is associated with a reduction in circulating insulin levels in patients with chronic HCV, particularly in genotype 1. In patients with NAFLD, the lack of a significant decrease in circulating insulin with weight reduction may reflect the higher initial BMI or may be due to the pathogenesis of this disorder.

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The trans-[RUCl(2)(L)(4)], trans-[Ru(NO)Cl (L)(4)](PF(6))(2) (L = isonicotinamide and 4-acetylpyridine) and trans-[Ru(NO)(OH)(py)(4)]Cl(2) (py = pyridine) complexes have been prepared and characterized by elemental analysis, UV-visible, infrared, and (1)H NMR spectroscopies, and cyclic voltammetry. The MLCT band energies of trans-[RUCl(2)(L)(4) increase in the order 4-acpy < isn < py. The reduction potentials of trans-[RuCl(2)(L)(4)] and trans-[Ru(NO)Cl(L)(4)](2+) increase in the order py < isn < 4-acpy. The stretching band frequency. v(NO), of the nitrosyl complexes ranges from 1913 to 1852 cm(-1) indicating a nitrosonium character for the NO ligand. Due to the large pi-acceptor ability of the equatorial ligands, the coordinated water is much more acidic in the water soluble trans-[Ru(NO)(H(2)O)(py)(4)](3+) than in trans-[Ru(NO)(H(2)O)(NH(3))(4)](3+) (C) 2009 Elsevier B.V. All rights reserved.

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Suramin is a polysulphonated napthylurea used as an antiprotozoal/anthelminitic drug, which also inhibits a broad range of enzymes. Suramin binding to recombinant human secreted group IIA phospholipase A(2) (hsPLA(2)GIIA) was investigated by molecular dynamics simulations (MD) and isothermal titration calorimetry (ITC). MD indicated two possible bound suramin conformations mediated by hydrophobic and electrostatic interactions with amino-acids in three regions of the protein. namely the active-site and residues located in the N- and C-termini, respectively. All three binding sites are located on the phospholipid membrane recognition surface, suggesting that suramin may inhibit the enzyme, and indeed a 90% reduction in hydrolytic activity was observed in the presence of 100 nM suramin. These results correlated with ITC data, which demonstrated 2.7 suramin binding sites on the hsPLA(2)GIIA, and indicates that suramin represents a novel class of phosphohpase A(2) inhibitor. (C) 2009 Elsevier Inc. All rights reserved.

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OBJECTIVE- To determine whether obesity increases platelet reactivity and thrombin activity in patients with type 2 diabetes plus stable coronary artery disease. RESEARCH DESIGN AND METHODS- We assessed platelet reactivity and markers of thrombin generation and activity in 193 patients from nine clinical sites of the Bypass Angioplasty Revascularization Investigation 2 Diabetes (BARI 2D). Blood taken at the time of enrollment was used for assay of the concentration of prothrombin fragment 1.2 (PT1.2, released when prothrombin is activated) and fibrinopeptide A (FPA, released when fibrinogen is cleaved). Platelet activation was identified with the use of flow cytometry in response to 0, 0.2, and 1 mu mol/l adenosine diphosphate (ADP). RESULTS- Concentrations of FPA, PT1.2, and platelet activation in the absence of agonist were low. Greater BMI was associated with higher platelet reactivity in response to 1 mu m ADP as assessed by surface expression of P-selectin (r = 0.29, P < 0.0001) but not reflected by the binding of fibrinogen to activated glycoprotein IIb-IIIa. BMI was not associated with concentrations of FPA or PT1.2. Platelet reactivity correlated negatively with A1C (P < 0.04), was not related to the concentration Of triglycerides in blood, and did not correlate with the concentration of C-reactive peptide. CONCLUSIONS- Among patients enrolled in this substudy of BARI 2D, a greater BMI was associated with higher platelet reactivity at the time of enrollment. Our results suggest that obesity and insulin resistance that accompanies obesity may influence platelet reactivity in patients with type 2 diabetes.

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Several published studies claim that high rates of N-2 fixation occur in sugarcane and sorghum, and have ascribed this result to infection by the bacterium Gluconacetobacter diazotrophicus, abetted by arbuscular mycorrhizal infection ( Glomus clarum). These results have not been confirmed within Australia. In this study, G. diazotrophicus was detected in stalks of field-grown sugarcane in Australia ( based on phenotypic tests, and a PCR test using species-specific primers developed to amplify a fragment of the G. diazotrophicus 16S rRNA gene). Isolates were nitrogenase positive ( acetylene reduction assay) in vitro. However, in glasshouse trials involving inoculation of sugarcane setts with G. diazotrophicus, co-inoculation with mycorrhizae, and plant growth under low N status, recovery of bacteria from maturing plants was variable. At 165 days from planting, no appreciable N-2-fixation, as assessed by dry weight increment, N budget, or N-15 ratio, of either an Australian or a Brazilian cultivar of sugarcane, or a sorghum cultivar, was achieved. We conclude that a N-2-fixing sugarcane - G. diazotrophicus association is not easily achievable, being primarily limited by a lack of infection.

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The purpose of the present substudy of the Lipid Treatment Assessment Project 2 was to assess dual C-reactive protein (CRP) and low-density lipoprotein (LDL) cholesterol goal attainment across a spectrum of low-, moderate-, and high-risk patients with dyslipidemia in 8 countries in North America, Latin America, Europe, and Asia. Of the 9,518 patients studied overall, 45% were women, 64% had hypertension, 31% had diabetes, 14% were current smokers, 60% were high risk, and 79% were taking a statin. The median CRP level was 1.5 mg/L (interquartile range 0.2 to 2.8). On multivariate analysis, higher CRP levels were associated with older age, female gender, hypertension, current smoking, greater body mass index, larger waist circumference, LDL cholesterol level, and triglyceride/high-density lipoprotein cholesterol ratio. In contrast, being from Asia or taking a statin was associated with lower levels. Across all risk groups, 59% of patients attained the CRP target of <2 mg/L, and 33% had <1 mg/L. Overall, 44% of patients attained both their National Cholesterol Education Program Adult Treatment Panel III LDL cholesterol target and a CRP level of <2 mg/L, but only 26% attained their LDL cholesterol target and a CRP level of <1 mg/L. In the very high-risk group with coronary heart disease and >= 2 risk factors, only 19% attained both their LDL cholesterol goal and a CRP level of <2 mg/L and 12% their LDL cholesterol goal and a CRP level of <1 mg/L. In conclusion, with current treatment, most dyslipidemic patients do not reach the dual CRP and LDL cholesterol goals. Smoking cessation, weight reduction, and the greater use of more potent statins at higher doses might be able to improve these outcomes. (C) 2011 Elsevier Inc. All rights reserved. (Am J Cardiol 2011;107:1639-1643)

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Background There are multitudes of procedures in plastic surgery used to correct hypertrophic and pendulous breasts in patients with heavy and ptotic breasts who need great resections of breast tissue, where the suprasternal notch-to-nipple distance is long and the use of nipple-areola transposition techniques is a challenge for the plastic surgeon. The purpose of this study is to present a technique of reduction mammaplasty that could solve these problems based on the following principles: mammary reduction utilizing a thin superior medial pedicle (0.8-1.5 cm thick) and the resection performed in two steps: (1) the base excess at a plane perpendicular to the breast (this determines the cone`s height) and (2) central half keel (this determines the breast diameter reduction). Methods Ninety patients with mammary hypertrophy were operated on at the ""Hospital das Clinicas,"" Sao Paulo University Medical School, between January 2000 and November 2005. Inclusion in this study required a minimum of 12-cm change in nipple position and a 750-g breast resection. Results The mean change in nipple position was 16 cm (range = 12-21 cm). The mean weight of each breast was 1400 (range = 750-3000 g).Considering the great amount of volume removed and the size of the operated breasts, few complications were observed and were similar to those reported following other techniques described in the literature. Patient satisfaction following this procedure was high. Conclusion The results of this study clearly demonstrate that thin superior medial pedicle reduction mammaplasty is a safe and reliable technique in cases of severe mammary hypertrophy.

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The synthesis, spectroscopy, and electrochemistry of the acyclic tertiary tetraamine copper(II) complex [CuL(1)](ClO4)(2) (L(1) = N,N-bis(2'-(dimethylamino)ethyl)-N,N'-dimethylpropane-1,3-diamine) is reported. The X-ray crystal structure of [CuL(1)(OClO3)(2)] reveals a tetragonally elongated CuN4O2 coordination sphere, exhibiting relatively long Cu-N bond lengths for a Cu-II tetraamine, and a small tetrahedral distortion of the CuN4 plane. The [CuL(1)](2+) ion displays a single, reversible, one-electron reduction at -0.06 V vs Ag/AgCl. The results presented herein illustrate the inherent difficulties associated with the separation and characterization of Cu-II complexes of tertiary tetraamines, and some previously incorrect assertions and unexplained observations of other workers are discussed.

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Sm14 and paramyosin are two major Schistosoma mansoni vaccine candidate antigens. Recently, we have identified Sm14 and paramyosin epitopes that are recognized by T cells of resistant individuals living in endemic areas for schistosomiasis. Herein, mice were immunized with these peptides separately or in association in order to evaluate their vaccine potential. Immunization of mice with Sm14 peptides alone or mixed with paramyosin peptides was able to induce 26%-36.7% or 28%-29.2% of worm burden reduction, 67% or 46% of intestinal eggs reduction and also 54%-61% or 43%-52% of liver pathology reduction, respectively. Protection was associated with a Th1 type of immune response induced by Sm14 peptide immunization. In contrast, paramyosin peptide vaccination did not engender protective immunity or liver pathology reduction and immunization was associated with a Th2 type of immune response. (C) 2008 Elsevier B.V. All rights reserved.

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Background: Forearm blood flow responses during mental stress are greater in individuals homozygous for the Glu27 allele. A high-fat meal is associated with impaired endothelium-dependent dilatation. We investigated the impact of high-fat ingestion on the muscle vasodilatory responses during mental stress in individuals with the Glu27 allele and those with the Gln27 allele of the beta(2)-adrenoceptor gene. Methods: A total of 162 preselected individuals were genotyped for the Glu27Gln beta(2)-adrenoceptor polymorphism. Twenty-four individuals participated in the study. Fourteen were homozygous for the Gln27 allele (Gln27Gln, 40 +/- 2 years; 64 +/- 2 kg), and 10 were homozygous for the Glu27 allele (Glu27Glu, 40 +/- 3 years; 65 +/- 3 kg). Forearm blood flow was evaluated by venous occlusion plethysmography before and after ingestion of 62 g of fat. Results: The high-fat meal caused no changes in baseline forearm vascular conductance (FVC, 2.2 +/- 0.1 vs. 2.4 +/- 0.2; P = 0.27, respectively), but reduced FVC responses to mental stress (1.5 +/- 0.2 vs. 0.8 +/- 0.2 units; P = 0.04). When volunteers were divided according to their genotypes, baseline FVC was not different between groups (Glu27Glu = 2.4 +/- 0.1 vs. Gln27Gln = 2.1 +/- 0.1 units; P = 0.08), but it was significantly greater in Glu27Glu individuals during mental stress (1.9 +/- 0.4 vs. 1.0 +/- 0.3 units; P = 0.04). High-fat intake eliminated the difference in FVC responses between Glu27Glu and Gln27Gln individuals (FVC, 1.3 +/- 0.4 vs. 1.2 +/- 0.4; P = 0.66, respectively). Conclusion: These findings demonstrate that a high-fat meal impairs muscle vasodilatation responses to mental stress in humans. However, this reduction can be attributed to the presence of the homozygous Glu27 allele of the beta(2)-adrenoceptor gene.

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Background-The Bypass Angioplasty Revascularization Investigation 2 Diabetes (BARI 2D) trial in 2368 patients with stable ischemic heart disease assigned before randomization to percutaneous coronary intervention or coronary artery bypass grafting strata reported similar 5-year all-cause mortality rates with insulin sensitization versus insulin provision therapy and with a strategy of prompt initial coronary revascularization and intensive medical therapy or intensive medical therapy alone with revascularization reserved for clinical indication(s). In this report, we examine the predefined secondary end points of cardiac death and myocardial infarction (MI). Methods and Results-Outcome data were analyzed by intention to treat; the Kaplan-Meier method was used to assess 5-year event rates. Nominal P values are presented. During an average 5.3-year follow-up, there were 316 deaths (43% were attributed to cardiac causes) and 279 first MI events. Five-year cardiac mortality did not differ between revascularization plus intensive medical therapy (5.9%) and intensive medical therapy alone groups (5.7%; P = 0.38) or between insulin sensitization (5.7%) and insulin provision therapy (6%; P = 0.76). In the coronary artery bypass grafting stratum (n = 763), MI events were significantly less frequent in revascularization plus intensive medical therapy versus intensive medical therapy alone groups (10.0% versus 17.6%; P = 0.003), and the composite end points of all-cause death or MI (21.1% versus 29.2%; P = 0.010) and cardiac death or MI (P = 0.03) were also less frequent. Reduction in MI (P = 0.001) and cardiac death/MI (P = 0.002) was significant only in the insulin sensitization group. Conclusions-In many patients with type 2 diabetes mellitus and stable ischemic coronary disease in whom angina symptoms are controlled, similar to those enrolled in the percutaneous coronary intervention stratum, intensive medical therapy alone should be the first-line strategy. In patients with more extensive coronary disease, similar to those enrolled in the coronary artery bypass grafting stratum, prompt coronary artery bypass grafting, in the absence of contraindications, intensive medical therapy, and an insulin sensitization strategy appears to be a preferred therapeutic strategy to reduce the incidence of MI. Clinical Trial Registration-URL: http://www.clinicaltrials.gov. Unique identifier: NCT00006305. (Circulation. 2009;120:2529-2540.)

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Purpose: To compare the efficacy and tolerability of the fixed combination of timolol maleate 0.5%/brimonidine tartrate 0.2% versus fixed combination of timolol maleate 0.5%/dorzolamide 2% in patients with elevated intraocular pressure (IOP) over 8 weeks. Patients and Methods: This 8-week, multicentric. interventional, randomized, open-label, parallel group study was conducted Lit 4 centers in Brazil and 1 center in Argentina. Patients with open-angle glaucoma or ocular hypertension were randomized to receive bilaterally fixed combination of brimonidine/timolol maleate 0.5% or fixed combination of dorzolamide 2%/timolol 0.5% twice daily at 8:00 AM and 8:00 PM. A modified diurnal tension curve (8:00 AM 10:30 AM, 02:00 PM, and 4:00 PM) followed by the water drinking test (WDT), which estimates IOP peak of diurnal tension curve, were performed in the baseline and week-8 visits. Adverse events data were recorded at each visit. Results: A total of 210 patients were randomized (brimonidine/timolol, n = 111; dorzolamide/timolol, n = 99). Mean baseline IOP was 23.43 +/- 3.22 mm Hg and 23.43 +/- 4.06 mm Hg in the patients treated with brimonidine/timolol and dorzolamide/timolol, respectively (P = 0.993). Mean diurnal IOP reduction after 8 weeks were 7.02 +/- 3.06 mm Hg and 6.91 +/- 3.67 mm Hg. respectively (P = 0.811). The adjusted difference between groups (analysis of covariance) Lit week 8 was not statistically significant (P = 0.847). Mean baseline WDT peak was 27.79 +/- 4.29 mm Hg in the brimonidine/timolol group and 27.68 +/- 5.46 mm Hg in the dorzolamide/timolol group. After 8 weeks of treatment, mean WDT peaks were 20.94 +/- 3.76 mm Hg (P < 0.001) and 20.98 +/- 4.19 (P < 0.001), respectively. The adjusted difference between groups (analysis of covariance) was not statistically significant (P = 0.469). No statistical difference in terms of adverse events was Found between groups. Conclusions: Both fixed combinations were capable of significantly reducing the mean diurnal IOP, mean diurnal peak, and mean WDT peak after 8 weeks of treatment. Also, both fixed combinations are well tolerated with few side effects.