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1.
Diabetes Obes Metab ; 24(3): 421-431, 2022 03.
Artigo em Inglês | MEDLINE | ID: mdl-34747087

RESUMO

AIM: To characterize the association between diabetes and transfusion and clinical outcomes in cardiac surgery, and to evaluate whether restrictive transfusion thresholds are harmful in these patients. MATERIALS AND METHODS: The multinational, open-label, randomized controlled TRICS-III trial assessed a restrictive transfusion strategy (haemoglobin [Hb] transfusion threshold <75 g/L) compared with a liberal strategy (Hb <95 g/L for operating room or intensive care unit; or <85 g/L for ward) in patients undergoing cardiac surgery on cardiopulmonary bypass with a moderate-to-high risk of death (EuroSCORE ≥6). Diabetes status was collected preoperatively. The primary composite outcome was all-cause death, stroke, myocardial infarction, and new-onset renal failure requiring dialysis at 6 months. Secondary outcomes included components of the composite outcome at 6 months, and transfusion and clinical outcomes at 28 days. RESULTS: Of the 5092 patients analysed, 1396 (27.4%) had diabetes (restrictive, n = 679; liberal, n = 717). Patients with diabetes had more cardiovascular disease than patients without diabetes. Neither the presence of diabetes (OR [95% CI] 1.10 [0.93-1.31]) nor the restrictive strategy increased the risk for the primary composite outcome (diabetes OR [95% CI] 1.04 [0.68-1.59] vs. no diabetes OR 1.02 [0.85-1.22]; Pinteraction  = .92). In patients with versus without diabetes, a restrictive transfusion strategy was more effective at reducing red blood cell transfusion (diabetes OR [95% CI] 0.28 [0.21-0.36]; no diabetes OR [95% CI] 0.40 [0.35-0.47]; Pinteraction  = .04). CONCLUSIONS: The presence of diabetes did not modify the effect of a restrictive transfusion strategy on the primary composite outcome, but improved its efficacy on red cell transfusion. Restrictive transfusion triggers are safe and effective in patients with diabetes undergoing cardiac surgery.


Assuntos
Procedimentos Cirúrgicos Cardíacos , Diabetes Mellitus , Infarto do Miocárdio , Procedimentos Cirúrgicos Cardíacos/efeitos adversos , Diabetes Mellitus/epidemiologia , Transfusão de Eritrócitos/efeitos adversos , Hemoglobinas/análise , Humanos , Infarto do Miocárdio/etiologia
2.
Bioresour Technol ; 318: 124050, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-32889118

RESUMO

Enzymatic hydrolysis of three pre-treated lignocellulosic biomasses -LCB- (wheat straw-WS-, corn stover-CSV- and cardoon stems -CS-) is studied. These biomasses were pre-treated by two methods: diluted sulfuric acid and acid ethanol-water extraction at six severity levels (H values). Pretreated solid fractions were hydrolyzed with commercial enzyme cocktails at standard conditions. A first-order kinetic fractal model was fitted to the experimental results. This model accurately describes the hydrolysis of all biomasses at all pre-treatment conditions studied. The results show that the formal first-order kinetic constant k depends on the biomass nature. The hydrolysis rate increases as the pre-treatment severity does, while the fractal exponent value h decreases. With these pre-treatments, and in terms of k and h, WS is highly reactive and, at medium H with EW pretreatment, highly accessible; CSV has a low reactivity and high accessibility and CS has the lowest reactivity and an increasing accessibility as severity rises.


Assuntos
Celulase , Biomassa , Fractais , Hidrólise , Lignina
3.
Eur Heart J ; 41(5): 645-651, 2020 02 01.
Artigo em Inglês | MEDLINE | ID: mdl-31237939

RESUMO

AIMS: To determine the 1-year risk of stroke and other adverse outcomes in patients with a new diagnosis of perioperative atrial fibrillation (POAF) after non-cardiac surgery. METHODS AND RESULTS: The PeriOperative ISchemic Evaluation (POISE)-1 trial evaluated the effects of metoprolol vs. placebo in 8351 patients, and POISE-2 compared the effect of aspirin vs. placebo, and clonidine vs. placebo in 10 010 patients. These trials included patients with, or at risk of, cardiovascular disease who were undergoing non-cardiac surgery. For the purpose of this study, we combined the POISE datasets, excluding 244 patients who were in atrial fibrillation (AF) at the time of randomization. Perioperative atrial fibrillation was defined as new AF that occurred within 30 days after surgery. Our primary outcome was the incidence of stroke at 1 year of follow-up; secondary outcomes were mortality and myocardial infarction (MI). We compared outcomes among patients with and without POAF using multivariable adjusted Cox proportional hazards models. Among 18 117 patients (mean age 69 years, 57.4% male), 404 had POAF (2.2%). The stroke incidence 1 year after surgery was 5.58 vs. 1.54 per 100 patient-years in patients with and without POAF, adjusted hazard ratio (aHR) 3.43, 95% confidence interval (CI) 2.00-5.90; P < 0.001. Patients with POAF also had an increased risk of death (incidence 31.37 vs. 9.34; aHR 2.51, 95% CI 2.01-3.14; P < 0.001) and MI (incidence 26.20 vs. 8.23; aHR 5.10, 95% CI 3.91-6.64; P < 0.001). CONCLUSION: Patients with POAF have a significantly increased risk of stroke, MI, and death at 1 year. Intervention studies are needed to evaluate risk reduction strategies in this high-risk population.


Assuntos
Fibrilação Atrial , Infarto do Miocárdio , Acidente Vascular Cerebral , Idoso , Fibrilação Atrial/epidemiologia , Feminino , Humanos , Masculino , Infarto do Miocárdio/epidemiologia , Infarto do Miocárdio/etiologia , Complicações Pós-Operatórias/epidemiologia , Fatores de Risco , Acidente Vascular Cerebral/epidemiologia , Acidente Vascular Cerebral/etiologia
4.
Bioresour Technol ; 280: 396-403, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-30784989

RESUMO

Liquor recycle in lignocellulosic biomass fractionation with ethanol-water has been studied. Runs have been carried out in a 6 L tank reactor with liquor recirculation. The liquors obtained in six successive fractioning operations have been analyzed together with the solid phase remnant. Experimental results revealed that the number of re-uses reduces solids recovery (from 52.2 to 42.6%) and cellulose recovery (from 28.1 to 23.3%) with minor or no effect on the hemicelluloses and lignin removal. The more remarkable effect is an increase of the glucose yield (from 76.7 to 95.3% after enzymatic hydrolysis during 72 h). The accumulation of acetic acid in the spent liquors (until 1.3 g/L) seems to be responsible of the higher enzymatic hydrolysis yield, from 76.3 (first use) to 87.7% (fifth re-use). Liquor re-use is effective to improve the sustainability of the pre-treatment obtaining a cellulose-rich solid easy to hydrolysate to sugars reducing energy consumption.


Assuntos
Bebidas Alcoólicas , Biomassa , Lignina/metabolismo , Ácido Acético/metabolismo , Fracionamento Químico/métodos , Etanol , Glucose/metabolismo , Hidrólise , Água
5.
J Biotechnol ; 292: 32-38, 2019 Feb 20.
Artigo em Inglês | MEDLINE | ID: mdl-30668958

RESUMO

The stabilization effects on a novel commercial ß-glucosidase preparation from Aspergillus fumigatus during saccharification of ethanol-water pretreated wheat straw were analysed in comparison to this enzyme stability during cellobiose hydrolysis. For this purpose, the kinetics of ß-glucosidase residual activity during cellobiose hydrolysis from 40 till 70 °C were studied, resulting in the fitting of a first-order partial deactivation model. Furthermore, a subsequent fitting of a kinetic model including this first-order deactivation equation and a Michaelis-Menten equation with double competitive inhibition by glucose and uncompetitive inhibition by cellobiose to released glucose was successful. Finally, global enzyme deactivation and prospective deactivation of enzyme remaining in the liquid phase were evaluated during wheat straw hydrolysis at 50 °C as a relevant saccharification process. Results suggest that the presence of a solid substrate dramatically reduces the global deactivation rate of the enzyme and, in addition, there is no loss the stability of the enzyme in the liquid phase along the saccharification process, even for 72 h.


Assuntos
Aspergillus fumigatus/enzimologia , Proteínas Fúngicas/metabolismo , Temperatura , Triticum , beta-Glucosidase/metabolismo , Celobiose/metabolismo , Estabilidade Enzimática , Etanol , Glucose/metabolismo , Hidrólise , Cinética , Água
6.
Bioresour Technol ; 270: 449-456, 2018 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-30245314

RESUMO

Ethanol-water (EW) and diluted sulfuric acid (DSA) pre-treatment have been studied for lignocellulosic biomass (corn stover, Cynara cardunculus L. stems and wheat straw). Both pre-treatments have been compared taken into account: solids recovery, glucans recovery, xylans removed, delignification and glucose yield. In all cases, the amount of energy involved has been taken as a criterion for sustainability. In general terms, EW is more efficient to remove lignin and DSA more appropriate to hydrolysate xylans. The combined effect of delignification and xylans removal is responsible for the improvement in the enzymatic cellulose hydrolysis. Under conditions of moderate-low energy inputs, EW pre-treatment yields better results than DSA with glucose yields in the range of 50-60% for EW pre-treated corn stover and cardoon stems; while wheat straw pulps reach up to 80%. So, multiple raw materials biorefinery needs a previous study to fit the type and conditions of the pre-treatment to each feedstock.


Assuntos
Cynara/metabolismo , Triticum/metabolismo , Zea mays/metabolismo , Biomassa , Celulose/metabolismo , Cynara/efeitos dos fármacos , Etanol/farmacologia , Hidrólise , Lignina/farmacologia , Ácidos Sulfúricos/farmacologia , Triticum/efeitos dos fármacos , Água/farmacologia , Xilanos/metabolismo , Zea mays/efeitos dos fármacos
7.
N Engl J Med ; 379(13): 1224-1233, 2018 09 27.
Artigo em Inglês | MEDLINE | ID: mdl-30146969

RESUMO

BACKGROUND: We reported previously that, in patients undergoing cardiac surgery who were at moderate-to-high risk for death, a restrictive transfusion strategy was noninferior to a liberal strategy with respect to the composite outcome of death from any cause, myocardial infarction, stroke, or new-onset renal failure with dialysis by hospital discharge or 28 days after surgery, whichever came first. We now report the clinical outcomes at 6 months after surgery. METHODS: We randomly assigned 5243 adults undergoing cardiac surgery to a restrictive red-cell transfusion strategy (transfusion if the hemoglobin concentration was <7.5 g per deciliter intraoperatively or postoperatively) or a liberal red-cell transfusion strategy (transfusion if the hemoglobin concentration was <9.5 g per deciliter intraoperatively or postoperatively when the patient was in the intensive care unit [ICU] or was <8.5 g per deciliter when the patient was in the non-ICU ward). The primary composite outcome was death from any cause, myocardial infarction, stroke, or new-onset renal failure with dialysis occurring within 6 months after the initial surgery. An expanded secondary composite outcome included all the components of the primary outcome as well as emergency department visit, hospital readmission, or coronary revascularization occurring within 6 months after the index surgery. The secondary outcomes included the individual components of the two composite outcomes. RESULTS: At 6 months after surgery, the primary composite outcome had occurred in 402 of 2317 patients (17.4%) in the restrictive-threshold group and in 402 of 2347 patients (17.1%) in the liberal-threshold group (absolute risk difference before rounding, 0.22 percentage points; 95% confidence interval [CI], -1.95 to 2.39; odds ratio, 1.02; 95% CI, 0.87 to 1.18; P=0.006 for noninferiority). Mortality was 6.2% in the restrictive-threshold group and 6.4% in the liberal-threshold group (odds ratio, 0.95; 95% CI, 0.75 to 1.21). There were no significant between-group differences in the secondary outcomes. CONCLUSIONS: In patients undergoing cardiac surgery who were at moderate-to-high risk for death, a restrictive strategy for red-cell transfusion was noninferior to a liberal strategy with respect to the composite outcome of death from any cause, myocardial infarction, stroke, or new-onset renal failure with dialysis at 6 months after surgery. (Funded by the Canadian Institutes of Health Research and others; TRICS III ClinicalTrials.gov number, NCT02042898 .).


Assuntos
Procedimentos Cirúrgicos Cardíacos/mortalidade , Transfusão de Eritrócitos/métodos , Complicações Pós-Operatórias/mortalidade , Adulto , Idoso , Procedimentos Cirúrgicos Cardíacos/efeitos adversos , Ponte Cardiopulmonar , Causas de Morte , Feminino , Seguimentos , Hemoglobinas/análise , Humanos , Estimativa de Kaplan-Meier , Modelos Logísticos , Masculino , Pessoa de Meia-Idade , Infarto do Miocárdio/etiologia , Complicações Pós-Operatórias/etiologia , Insuficiência Renal/etiologia , Acidente Vascular Cerebral/etiologia
8.
Bioresour Technol ; 268: 592-598, 2018 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-30138871

RESUMO

A physico-chemical kinetic model for the hydrolysis of pre-treated corn stover is proposed. This model takes into account two reactions in series, the hydrolysis of cellulose to cellobiose and the production of glucose from cellobiose. Experiments have been carried out with an industrial enzymatic cocktail from Trichoderma reesei containing endo and exoglucanases and a very low activity of ß-glucosidase. Kinetic parameters were calculated by fitting the proposed model to experimental data of cellulose and glucose concentrations with time. The kinetic parameters fulfilled all relevant statistical and physical criteria. The kinetic model has been validated with published saccharification data regarding differently pre-treated corn stover and enzymatic cocktail, in this case with a very high ß-glucosidase activity (as it is common in modern industrial cellulase cocktails). In both cases, the kinetic model proposed could be fitted very appropriately to cellulose hydrolysis data.


Assuntos
Eliminação de Resíduos , Zea mays , Celulase , Explosões , Hidrólise , Vapor
9.
Bioresour Technol ; 256: 178-186, 2018 May.
Artigo em Inglês | MEDLINE | ID: mdl-29438918

RESUMO

The fractionation of wheat straw by ethanol-water (EW) pre-treatment was studied regarding its main operating conditions: time, temperature, L/S ratio and ethanol percentage were optimized by using an orthogonal experimental design (Taguchi). Afterwards, diluted sulfuric acid (DSA) hydrolysis and EW treatments have been compared in terms of energy consumption and yield of a cellulosic solid residue able to be enzymatically hydrolyzed to glucose. Experimental results show that temperature is the only variable of EW with a significant effect on the quality of the pretreated solids. EW pre-treatment of wheat straw is more effective than DSA hydrolysis due to its higher capacity of delignification. Moreover, a high glucose yield (80%) can be obtained by enzymatic hydrolysis of a solid pretreated with a moderate energy input EW (160 °C, 45 min) while wheat straw needs of a higher energy input during DSA to produce a similar yield of glucose after saccharification.


Assuntos
Etanol , Triticum , Fermentação , Hidrólise , Ácidos Sulfúricos , Água
10.
N Engl J Med ; 377(22): 2133-2144, 2017 11 30.
Artigo em Inglês | MEDLINE | ID: mdl-29130845

RESUMO

BACKGROUND: The effect of a restrictive versus liberal red-cell transfusion strategy on clinical outcomes in patients undergoing cardiac surgery remains unclear. METHODS: In this multicenter, open-label, noninferiority trial, we randomly assigned 5243 adults undergoing cardiac surgery who had a European System for Cardiac Operative Risk Evaluation (EuroSCORE) I of 6 or more (on a scale from 0 to 47, with higher scores indicating a higher risk of death after cardiac surgery) to a restrictive red-cell transfusion threshold (transfuse if hemoglobin level was <7.5 g per deciliter, starting from induction of anesthesia) or a liberal red-cell transfusion threshold (transfuse if hemoglobin level was <9.5 g per deciliter in the operating room or intensive care unit [ICU] or was <8.5 g per deciliter in the non-ICU ward). The primary composite outcome was death from any cause, myocardial infarction, stroke, or new-onset renal failure with dialysis by hospital discharge or by day 28, whichever came first. Secondary outcomes included red-cell transfusion and other clinical outcomes. RESULTS: The primary outcome occurred in 11.4% of the patients in the restrictive-threshold group, as compared with 12.5% of those in the liberal-threshold group (absolute risk difference, -1.11 percentage points; 95% confidence interval [CI], -2.93 to 0.72; odds ratio, 0.90; 95% CI, 0.76 to 1.07; P<0.001 for noninferiority). Mortality was 3.0% in the restrictive-threshold group and 3.6% in the liberal-threshold group (odds ratio, 0.85; 95% CI, 0.62 to 1.16). Red-cell transfusion occurred in 52.3% of the patients in the restrictive-threshold group, as compared with 72.6% of those in the liberal-threshold group (odds ratio, 0.41; 95% CI, 0.37 to 0.47). There were no significant between-group differences with regard to the other secondary outcomes. CONCLUSIONS: In patients undergoing cardiac surgery who were at moderate-to-high risk for death, a restrictive strategy regarding red-cell transfusion was noninferior to a liberal strategy with respect to the composite outcome of death from any cause, myocardial infarction, stroke, or new-onset renal failure with dialysis, with less blood transfused. (Funded by the Canadian Institutes of Health Research and others; TRICS III ClinicalTrials.gov number, NCT02042898 .).


Assuntos
Procedimentos Cirúrgicos Cardíacos , Transfusão de Eritrócitos/métodos , Adulto , Idoso , Procedimentos Cirúrgicos Cardíacos/efeitos adversos , Procedimentos Cirúrgicos Cardíacos/mortalidade , Ponte Cardiopulmonar , Feminino , Hemoglobinas/análise , Mortalidade Hospitalar , Humanos , Unidades de Terapia Intensiva , Análise de Intenção de Tratamento , Tempo de Internação , Masculino , Pessoa de Meia-Idade , Infarto do Miocárdio/etiologia , Assistência Perioperatória , Complicações Pós-Operatórias/etiologia , Complicações Pós-Operatórias/mortalidade , Insuficiência Renal/etiologia , Acidente Vascular Cerebral/etiologia
11.
Bioengineering (Basel) ; 4(4)2017 Nov 28.
Artigo em Inglês | MEDLINE | ID: mdl-29182575

RESUMO

The effect of the addition of two [4-butyltrimethylammonium]-xylan chloride polyelectrolytes (BTMAXs) on bacterial cellulose (BC) was evaluated. The first strategy was to add the polyelectrolytes to the culture medium together with a cell suspension of the bacterium. After one week of cultivation, the films were collected and purified. The second approach consisted of obtaining a purified and homogenized BC, to which the polyelectrolytes were added subsequently. The films were characterized in terms of tear and burst indexes, optical properties, surface free energy, static contact angle, Gurley porosity, SEM, X-ray diffraction and AFM. Although there are small differences in mechanical and optical properties between the nanocomposites and control films, the films obtained by BC synthesis in the presence of BTMAXs were remarkably less opaque, rougher, and had a much lower specular gloss. The surface free energy depends on the BTMAXs addition method. The crystallinity of the composites is lower than that of the control material, with a higher reduction of this parameter in the composites obtained by adding the BTMAXs to the culture medium. In view of these results, it can be concluded that BC-BTMAX composites are a promising new material, for example, for paper restoration.

12.
Bioresour Technol ; 220: 110-116, 2016 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-27566519

RESUMO

Enzymatic hydrolysis of corn stover was studied at agitation speeds from 50 to 500rpm in a stirred tank bioreactor, at high solid concentrations (20% w/w dry solid/suspension), 50°C and 15.5mgprotein·gglucane(-1). Two empirical kinetic models have been fitted to empirical data, namely: a potential model and a fractal one. For the former case, the global order dramatically decreases from 13 to 2 as agitation speed increases, suggesting an increment in the access of enzymes to cellulose in terms of chemisorption followed by hydrolysis. For its part, the fractal kinetic model fits better to data, showing its kinetic constant a constant augmentation with increasing agitation speed up to a constant value at 250rpm and above, when mass transfer limitations are overcome. In contrast, the fractal exponent decreases with rising agitation speed till circa 0.19, suggesting higher accessibility of enzymes to the substrate.


Assuntos
Ácidos/metabolismo , Celulose/metabolismo , Modelos Teóricos , Zea mays/enzimologia , Zea mays/metabolismo , Reatores Biológicos , Celulase , Fractais , Hidrólise , Cinética
13.
Bioresour Technol ; 216: 28-35, 2016 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-27233094

RESUMO

The effect of fluid dynamic conditions on enzymatic hydrolysis of acid pretreated corn stover (PCS) has been assessed. Runs were performed in stirred tanks at several stirrer speed values, under typical conditions of temperature (50°C), pH (4.8) and solid charge (20% w/w). A complex mixture of cellulases, xylanases and mannanases was employed for PCS saccharification. At low stirring speeds (<150rpm), estimated mass transfer coefficients and rates, when compared to chemical hydrolysis rates, lead to results that clearly show low mass transfer rates, being this phenomenon the controlling step of the overall process rate. However, for stirrer speed from 300rpm upwards, the overall process rate is controlled by hydrolysis reactions. The ratio between mass transfer and overall chemical reaction rates changes with time depending on the conditions of each run.


Assuntos
Biomassa , Lignina/química , Eliminação de Resíduos/métodos , Zea mays/química , Celulose/química , Hidrodinâmica , Hidrólise
14.
Appl Spectrosc ; 70(9): 1537-45, 2016 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-27129363

RESUMO

A new method was developed to study how the oil and cyan pigments of cold-set ink are distributed in newspaper thickness. The methodology involved laboratory printing followed by delamination of the printed paper. The unprinted side, printed side, and resulting layers were analyzed using attenuated total reflection Fourier transform infrared spectroscopy (ATR FT-IR). Three commercial newspapers and black and cyan cold-set inks were chosen for the study. Attenuated total reflection Fourier transform infrared spectroscopy enabled the proportion of oil and cyan pigment on the printed surface and throughout the sheet thickness to be measured. Oil percentage was evaluated as the area increment of the region from 2800 cm(-1) to 3000 cm(-1) The relative amount of cyan pigment was determined as the area of the absorption band at 730 cm(-1) The ink oil was found mainly below half the paper thickness, whereas the pigment was detected at the layers closer to the printed surface, at a depth penetration of less than 15 µm (20% of thickness). Distribution of these two components in paper thickness depended on the type of cold-set ink, the amount of ink transferred, and the newspaper properties.

15.
Carbohydr Polym ; 116: 173-81, 2015 Feb 13.
Artigo em Inglês | MEDLINE | ID: mdl-25458287

RESUMO

Bacterial cellulose (BC) synthesized by Gluconacetobacter sucrofermentans CECT 7291 seems to be a good option for the restoration of degraded paper. In this work BC layers are cultivated and purified by two different methods: an alkaline treatment when the culture media contains ethanol and a thermal treatment if the media is free from ethanol. The main goal of these tests was the characterization of BC layers measured in terms of tear and burst indexes, optical properties, SEM, X-ray diffraction, FTIR, degree of polymerization, static and dynamic contact angles, and mercury intrusion porosimetry. The BC layers were also evaluated in the same terms after an aging treatment. Results showed that BC has got high crystallinity index, low internal porosity, good mechanical properties and high stability over time, especially when purified by the alkaline treatment. These features make BC an adequate candidate for degraded paper reinforcement.


Assuntos
Celulose/química , Papel , Celulose/isolamento & purificação , Celulose/metabolismo , Etanol/química , Gluconacetobacter/metabolismo , Temperatura Alta , Porosidade , Espectroscopia de Infravermelho com Transformada de Fourier , Viscosidade , Difração de Raios X
16.
Bioresour Technol ; 167: 186-91, 2014 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-24980031

RESUMO

Steam explosion and steam pre-treatment have proved capable of enhancing enzymatic saccharification of lignocellulosic materials. However, until now, these methods had not been compared under the same operational conditions and using the same raw material. Both pre-treatments lead to increased yields in the saccharification of Eucalyptus globulus; but results have been better with steam pre-treatments, despite the more accessible surface of exploded samples. The reason for this finding could be enzymatic inhibition: steam explosion causes a more extensive extraction of hemicelluloses and releases a greater amount of degradation products which can inhibit enzymatic action. Enzymatic inhibition is also dependent on the amount and chemical structure of lignin, which was also a contributing factor to the lower enzymatic yields obtained with the most severe pre-treatment. Thus, the highest yields (46.7% glucose and 73.4% xylose yields) were obtained after two cycle of steam treatment, of 5 and 3 min, at 183°C.


Assuntos
Biotecnologia/métodos , Metabolismo dos Carboidratos , Celulase/metabolismo , Eucalyptus/metabolismo , Vapor , Glucose/análise , Lignina/isolamento & purificação , Xilanos/isolamento & purificação , Xilose/análise
17.
Bioresour Technol ; 153: 236-44, 2014 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-24368272

RESUMO

Growing interest in alternative and renewable energy sources has brought increasing attention to the integration of a pulp mill into a forest biorefinery, where other products could be produced in addition to pulp. To achieve this goal, hemicelluloses were extracted, either by steam explosion or by steam treatment, from Eucalyptus globulus wood prior to pulping. The effects of both pre-treatments in the subsequent kraft pulping and paper strength were evaluated. Results showed a similar degree of hemicelluloses extraction with both options (32-67% of pentosans), which increased with the severity of the conditions applied. Although both pre-treatments increased delignification during pulping, steam explosion was significantly better: 12.9 kappa number vs 22.6 for similar steam unexploded pulps and 40.7 for control pulp. Finally, similar reductions in paper strength were found regardless of the type of treatment and conditions assayed, which is attributed to the increase of curled and kinked fibers.


Assuntos
Biotecnologia/métodos , Eucalyptus/química , Papel , Polissacarídeos/isolamento & purificação , Vapor , Árvores/química , Celulose/química , Fracionamento Químico , Eucalyptus/efeitos dos fármacos , Hidrólise/efeitos dos fármacos , Lignina/química , Hidróxido de Sódio/farmacologia , Resistência à Tração/efeitos dos fármacos , Viscosidade/efeitos dos fármacos , Água/química , Madeira/química
18.
J Agric Food Chem ; 59(16): 8761-9, 2011 Aug 24.
Artigo em Inglês | MEDLINE | ID: mdl-21749069

RESUMO

Eucalyptus globulus chips were steam exploded followed by treatment with a laccase-mediator system (LMS) under different experimental conditions. Removal of hemicelluloses and, to a lesser extent, lignin was observed. Thermogravimetic analyses of whole meal obtained from chips before and after steam explosion indicated an increase in lignin degradation temperature due to lignin condensation. In contrast, application of LMS treatment caused a reduction in lignin and polysaccharide degradation temperatures. Lignins were isolated from wood samples before and after each treatment and analyzed by 2D NMR and (13)C NMR. An increase in carboxyl and phenolic hydroxyl groups and a significant decrease in ß-O-4 structures were found in steam-exploded samples. The most relevant changes observed after laccase treatment were increased secondary OH and degree of condensation.


Assuntos
Eucalyptus/química , Lacase , Lignina/análise , Vapor , Madeira/química , Pressão
19.
Rev. colomb. cardiol ; 16(3): 128-136, may.-jun. 2009.
Artigo em Espanhol | LILACS | ID: lil-534573

RESUMO

Introducción: los cambios demográficos recientes condujeron a un aumento del riesgo de eventos vasculares mayores después de cirugía no cardiaca. El monitoreo con troponina y electrocardiografía identificaría más de estos eventos. Métodos: de manera prospectiva se recolectaron datos de pacientes elegibles (mayores de 45 años no seleccionados sometidos a cirugía no cardiaca, bajo anestesia regional o general, con estancia hospitalaria prevista mayor o igual a 24 horas en dos hospitales de Bucaramanga), durante dos períodos de tiempo, antes y después de monitoreo diagnóstico post-operatorio (evaluaciones seriadas de troponina T y electrocardiogramas sin conocimiento de datos clínicos). Para el componente de tiempo anterior a la intervención (cuidado clínico convencional), se tomaron historias clínicas de todos los pacientes elegibles de una muestra aleatoria de tres meses correspondientes a 2005. Para el componente de tiempo posterior al monitoreo, se siguieron 100 pacientes elegibles consecutivos. El desenlace primario fue la incidencia de eventos vasculares mayores intrahospitalarios, incluyendo infarto del miocardio (definido como troponina elevada asociada a cambios electrocardiográficos sugestivos, independiente de los síntomas). Resultados: se incluyeron 534 historias clínicas y 100 pacientes quirúrgicos prospectivos (edad media 62,2 años, DE 12,9; 56% mujeres). El tipo de cirugía más frecuente fue la ortopédica (26,8%) seguida de la intra-abdominal (20,2%). La incidencia de eventos fue 2,8% en historias clínicas, en comparación con una incidencia de 7% en pacientes sometidos a monitoreo (p = 0,071). Los cuatro infartos del miocardio identificados en estos pacientes fueron silentes. Conclusión: el monitoreo diagnóstico post-operatorio con troponina y electrocardiografía, identificó una mayor proporción de eventos vasculares, principalmente infartos silentes del miocardio.


Introduction: recent demographic changes have led to an increased risk of major vascular events among patients undergoing non-cardiac surgery. Troponin and electrocardiogram monitoring would further identify these major vascular events. Methods: we prospectively collected data on elegible patients (non-selected individuals aged 45 or older undergoing non-cardiac surgery under general or regional anesthesia in two hospitals in Bucaramanga, with expected length of stay longer than 24 hours) during a time-interrupted series, before and after postoperative diagnostic monitoring (blinded assessment of troponin T and electrocardiograms ignoring clinical data). For the period before the intervention (usual clinical care), two independent reviewers extracted clinical information from clinical histories (of all eligible patients from 3 randomly-selected months of 2005). For the period after diagnostic monitoring, we followed 100 consecutive eligible patients. Primary outcome was a composite of major vascular events within hospital, including myocardial infarction (defined as any troponin elevation associated with electrocardiographic changes suggesting ischemia, regardless of symptoms). Results: we included 534 clinical charts and 100 prospective surgical patients (mean age 62.2, SD 12.9 years; 56% women). The more frequent surgical procedures were orthopedics (26.8%) followed by abdominal (20.2%). The incidence of major vascular events recorded in clinical charts was 2.8%, compared with 7% among monitored patients (p=0,071). All four myocardial infarctions identified among the later group were silent. Conclusion: postoperative monitoring with troponin and electrocardiography identified a higher proportion of major vascular events, mainly silent myocardial infarctions.


Assuntos
Cirurgia Geral , Mortalidade , Infarto do Miocárdio , Troponina
20.
Int J Nurs Stud ; 46(11): 1496-504, 2009 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-19411076

RESUMO

OBJECTIVE: To determine the impact of early mobilisation (EM) on total mortality and non-fatal re-infarction after acute myocardial infarction (AMI). DESIGN: Systematic review and meta-analysis. DATA SOURCES: MEDLINE, CINAHL, HealthStar, EMBASE, the Cochrane Library Controlled Trials Registry and experts. METHODS: Target studies included published and unpublished experimental, controlled studies in any language comparing AMI patients allocated to any in-hospital early mobilisation or a control/standard treatment. Two reviewers independently assessed study eligibility and quality and performed data extraction. We calculated relative risks (RRs) and 95% confidence intervals (CIs) using the random-effects model. OUTCOMES: All-cause mortality or re-infarction up to 1-year post-AMI. RESULTS: Out of 385 potentially relevant studies, 14 met our eligibility criteria (13 published before 1983). There were 149 deaths (9.3% of 1607) and 82 non-fatal re-infarctions (5.2% of 1580) among post-AMI patients receiving EM, compared with 179 deaths (11.6% of 1541) and 80 non-fatal re-infarctions (5.3% of 1518) among AMI patients receiving control treatment (RR=0.85, 95% CI 0.68, 1.05 and RR=1.02, 95% CI 0.75, 1.39 respectively). CONCLUSION: Our meta-analysis demonstrated a trend towards decreased mortality with EM after AMI. However, there is uncertainty about early mobilisation and more research should be developed having into account all kind of differences among patients receiving treatment after AMI worldwide.


Assuntos
Infarto do Miocárdio/fisiopatologia , Caminhada , Humanos
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