956 resultados para Organosolv pretreatment
Resumo:
The efficient utilization of lignocellulosic biomass and the reduction of production cost are mandatory to attain a cost-effective lignocellulose-to-ethanol process. The selection of suitable pretreatment that allows an effective fractionation of biomass and the use of pretreated material at high-solid loadings on saccharification and fermentation (SSF) processes are considered promising strategies for that purpose. Eucalyptus globulus wood was fractionated by organosolv process at 200 C for 69 min using 56% of glycerol-water. A 99% of cellulose remained in pretreated biomass and 65% of lignin was solubilized. Precipitated lignin was characterized for chemical composition and thermal behavior, showing similar features to commercial lignin. In order to produce lignocellulosic ethanol at high-gravity, a full factory design was carried to assess the liquid to solid ratio (3e9 g/g) and enzyme to solid ratio (8e16 FPU/g) on SSF of delignified Eucalyptus. High ethanol concentration (94 g/L) corresponding to 77% of conversion at 16FPU/g and LSR ¼ 3 g/g using an industrial and thermotolerant Saccharomyces cerevisiae strain was successfully produced from pretreated biomass. Process integration of a suitable pretreatment, which allows for whole biomass valorization, with intensified saccharification-fermentation stages was shown to be feasible strategy for the co-production of high ethanol titers, oligosaccharides and lignin paving the way for cost-effective Eucalyptus biorefinery.
Resumo:
This the tenth in a series of symposia devoted to talks by students on their biochemical engineering research. The first, third, fifth, and ninth were at Kansas State University in Manhattan, the second and fourth were at the University of Nebraska–Lincoln, the sixth was in Kansas City in conjunction with the 81st American Institute of Chemical Engineers National Meeting, the seventh was at Iowa State University in Ames, and the eighth was held at the University of Missouri–Columbia. Contents"Combined Autohydrolysis-Organosolv Pretreatment of Lignocellulosic Materials," Robert A. Lewis, Colorado State University "An Investigation of Cellulase Activity Assays," Minhhuong Nguyen, University of Missouri–Columbia "Action Pattern of a Xylobiohydrolase from Aspergillus niger," Mary M. Frederick, Iowa State University "Estimation of Heats of Combustion of Biomass from Elemental Analysis Using Available Electron Concepts," Snehal A. Patel, Kansas State University "Design of a Wheat Straw to Ethanol Conversion Facility," Michael M. Meagher, Colorado State University "Effects of Salt, Heat, and Physical Form on the Fermentation of Bananas," Carl Drewel, University of Missouri–Columbia "Gas Hold-up in the Downflow Section of a Split Cylinder Airlift Column," Vasanti Deshpande, Kansas State University "Measurement of Michaelis Constants for Soluble and Immobilized Glucoamylase," Robert A. Lesch, Iowa State University "Kinetics of Alkaline Oxidation and Degradation of Sugars," Alfred R. Fratzke, Iowa State University "Stability of Cereal Protein During Microbial Growth on Grain Dust," Bamidele O. Solomon, Kansas State University
Resumo:
The present work describes non-conventional sisal (Agave sisalana) chemical (organosolv) pulp from residues of cordage as reinforcement to cement based materials. Sisal organosolv pulp was produced in a 1:1 ethanol/water mixture and post chemically and physically characterized in order to compare its properties with sisal kraft pulp. Cement based composites reinforced with organosolv or kraft pulps and combined with polypropylene (PP) fibres were produced by the slurry de-watering and pressing method as a crude simulation of the Hatschek process. Composites were evaluated at 28 days of age, after exposition to accelerated carbonation and after 100 soak/dry cycles. Composites containing organosolv pulp presented lower mechanical strength, water absorption and apparent porosity than composites reinforced with kraft pulp. The best mechanical performance after ageing was also achieved by samples reinforced with kraft pulp. The addition of PP fibres favoured the maintenance of toughness after ageing. Accelerated carbonation promoted the densification of the composites reinforced with sisal organosolv + PP fibres.
Resumo:
Experiments based on a 2(3) central composite full factorial design were carried out in 200-ml stainless-steel containers to study the pretreatment, with dilute sulfuric acid, of a sugarcane bagasse sample obtained from a local sugar-alcohol mill. The independent variables selected for study were temperature, varied from 112.5A degrees C to 157.5A degrees C, residence time, varied from 5.0 to 35.0 min, and sulfuric acid concentration, varied from 0.0% to 3.0% (w/v). Bagasse loading of 15% (w/w) was used in all experiments. Statistical analysis of the experimental results showed that all three independent variables significantly influenced the response variables, namely the bagasse solubilization, efficiency of xylose recovery in the hemicellulosic hydrolysate, efficiency of cellulose enzymatic saccharification, and percentages of cellulose, hemicellulose, and lignin in the pretreated solids. Temperature was the factor that influenced the response variables the most, followed by acid concentration and residence time, in that order. Although harsher pretreatment conditions promoted almost complete removal of the hemicellulosic fraction, the amount of xylose recovered in the hemicellulosic hydrolysate did not exceed 61.8% of the maximum theoretical value. Cellulose enzymatic saccharification was favored by more efficient removal of hemicellulose during the pretreatment. However, detoxification of the hemicellulosic hydrolysate was necessary for better bioconversion of the sugars to ethanol.
Wilson`s disease: two treatment modalities. Correlations to pretreatment and posttreatment brain MRI
Resumo:
Brain magnetic resonance imaging (MRI) studies on Wilson`s disease (WD) show lack of correlations between neurological and neuroimaging features. Long-term follow-up reports with sequential brain MRI in patients with neurological WD comparing different modalities of treatment are scarce. Eighteen patients with neurological WD underwent pretreatment and posttreatment brain MRI scans to evaluate the range of abnormalities and the evolution along these different periods. All patients underwent at least two MRI scans at different intervals, up to 11 years after the beginning of treatment. MRI findings were correlated with clinical picture, clinical severity, duration of neurological symptoms, and treatment with two different drugs. Patients were divided into two groups according to treatment: d-penicillamine (D-P), zinc (Zn), and Zn after the onset of severe intolerance to D-P. MRI scans before treatment showed, in all patients, hypersignal intensity lesions on T2- and proton-density-weighted images bilaterally and symmetrically at basal nuclei, thalamus, brain stem, cerebellum, brain cortex, and brain white matter. The most common neurological symptoms were: dysarthria, parkinsonism, dystonia, tremor, psychiatric disturbances, dysphagia, risus sardonicus, ataxia, chorea, and athetosis. From the neurological point of view, there was no difference on the evolution between the group treated exclusively with D-P and the one treated with Zn. Analysis of MRI scans with longer intervals after the beginning of treatment depicted a trend for neuroimaging worsening, without neurological correspondence, among patients treated with Zn. Neuroimaging pattern of evolution was more favorable for the group that received exclusively D-P.
Resumo:
Salivary contamination is one of the factors that can disturb the sealing process and interfere in the longevity of pit and fissure sealants. Erbium : yttrium-aluminum-garnet (Er : YAG) laser could influence the bond strength of enamel and increase the acid resistance. To evaluate the influence of Er : YAG laser on the shear bond strength of a sealant to a salivary contaminated enamel surface. Twenty-four third molars had the roots sectioned 2 mm coronal to the cementoenamel junction. The crowns were mesiodistally sectioned providing 48 halves that were embedded in polyester resin. Enamel was flattened and a 2-mm diameter bonding area was demarcated. Specimens were randomly assigned to two groups according to the superficial pretreatment-37% phosphoric acid (A) and Er : YAG laser (80 mJ/2 Hz) + phosphoric acid (L), which were subdivided into two groups (N = 12), without salivary contamination (C) and with salivary contamination (SC). To contaminate the specimens, 0.25 mL of human fresh saliva was applied for 20 seconds and then dried. Fluroshield sealant was applied in all specimens. After storage, shear bond strength of samples were tested in a universal testing machine. Means in MPa were: AC-14.61 (+/- 2.52); ASC-6.66 (+/- 2.34); LC-11.91 (+/- 1.34); and LSC-2.22 (+/- 0.66). Statistical analysis revealed that surfaces without salivary contamination and with acid treatment had the highest mean (p < 0.05). The group with salivary contamination treated by Er : YAG laser followed by phosphoric acid application presented the lowest bond values (p < 0.05). The phosphoric acid etching under dry condition yielded better bonding performance. Er : YAG laser was not able to increase the effectiveness of conventional acid etching of enamel in the bond of sealants in both dry and wet conditions. Under the conditions of this study, the conventional etching protocol (phosphoric acid without salivary contamination) is still preferable to laser-conditioning enamel surface prior to sealant application.
Resumo:
Background/Aims: These studies investigated the role of apoptosis following ischaemia/reperfusion (I/R) injury to the liver and the effect of pretreatment with Cyclosporin A. Methods: Male Sprague-Dawley rats received 30 min of warm ischaemia followed by a period of reperfusion of 6 h. Rats were given olive oil or Cyclosporin A (30 mg/kg p.o.) the day before surgery. Neutrophil numbers were assessed in haematoxylin-eosin-stained sections of liver. In situ staining of sections using TdT-mediated dUTP-fluoreseein nick-end labelling was carried out to determine the extent of apoptosis, followed by electron microscopy. Semi-quantitative polymerase chain reaction (PCR) analysis of the transcript for Fas antigen was performed. Results and Conclusions: High levels of apoptosis were observed in I/R injury, which were greatly ameliorated in Cyclosporin A-pretreated groups. PCR analysis indicated a reduction in the level of expression of Fas transcript in Cyclosporin A-treated rats. Histological analysis showed a significant increase in the number of neutrophils infiltrating I/R-injured tissue (62 +/- 10.69, it = 16), which was markedly reduced by Cyclosporin A pretreatment (16 +/- 7, n = 6, P < 0.05). These results indicate a role of parenchymal apoptosis in the pathogenesis of I/R injury, which occurs in association with neutrophil infiltration, both of which can be significantly reduced by Cyclosporin A pretreatment. (C) 2002 European Association for the Study of the Liver. Published by Elsevier Science B.V. All rights reserved.
Resumo:
Purpose. The flux of a topically applied drug depends on the activity in the skin and the interaction between the vehicle and skin. Permeation of vehicle into the skin can alter the activity of drug and the properties of the skin barrier. The aim of this in vitro study was to separate and quantify these effects. Methods. The flux of four radiolabeled permeants (water, phenol, diflunisal, and diazepam) with log K-oct/water values from 1.4 to 4.3 was measured over 4 h through heat-separated human epidermis pretreated for 30 min with vehicles having Hildebrand solubility parameters from 7.9 to 23.4 (cal/cm(3))(1/2). Results. Enhancement was greatest after pretreatment with the more lipophilic vehicles. A synergistic enhancement was observed using binary mixtures. The flux of diazepam was not enhanced to the same extent as the other permeants, possibly because its partitioning into the epidermis is close to optimal (log K-oct 2.96). Conclusion. An analysis of the permeant remaining in the epidermis revealed that the enhancement can be the result of either increased partitioning of permeant into the epidermis or an increasing diffusivity of permeants through the epidermis.
Resumo:
OBJECTIVES: To assess the prevalence and correlates of childhood and adolescent sexual and/or physical abuse (SPA) in bipolar I disorder (BDI) patients treated for a first episode of psychotic mania. METHODS: The Early Psychosis Prevention and Intervention Centre admitted 786 first-episode psychosis patients between 1998 and 2000. Data were collected from patients' files using a standardized questionnaire. A total of 704 files were available; 43 were excluded because of a nonpsychotic diagnosis at endpoint and 3 due to missing data regarding past stressful events. Among 658 patients with available data, 118 received a final diagnosis of BDI and were entered in this study. RESULTS: A total of 80% of patients had been exposed to stressful life events during childhood and adolescence and 24.9% to SPA; in particular, 29.8% of female patients had been exposed to sexual abuse. Patients who were exposed to SPA had poorer premorbid functioning, higher rates of forensic history, were less likely to live with family during treatment period, and were more likely to disengage from treatment. CONCLUSIONS: SPA is highly prevalent in BDI patients presenting with a first episode of psychotic mania; exposed patients have lower premorbid functional levels and poorer engagement with treatment. The context in which such traumas occur must be explored in order to determine whether early intervention strategies may contribute to diminish their prevalence. Specific psychological interventions must also be developed.
Resumo:
OBJECTIVES: The role of beta-blockers in the treatment of hypertension is discussed controversially and the data showing a clear benefit in acute coronary syndromes (ACS) were obtained in the thrombolysis era. The goal of this study was to analyze the role of pretreatment with beta-blockers in patients with ACS. METHODS: Using data from the Acute Myocardial Infarction in Switzerland (AMIS Plus) registry, we analyzed outcomes of patients with beta-blocker pretreatment in whom they were continued during hospitalization (group A), those without beta-blocker pretreatment but with administration after admission (group B) and those who never received them (group C). Major adverse cardiac events defined as composed endpoint of re-infarction and stroke (during hospitalization) and/or in-hospital death were compared between the groups. RESULTS: A total of 24,709 patients were included in the study (6,234 in group A, 12,344 in group B, 6,131 in group C). Patients of group B were younger compared to patients of group A and C (62.5, 67.6 and 68.4, respectively). In the multivariate analysis, odds ratio for major adverse cardiac events was 0.59 (CI 0.47-0.74) for group A and 0.66 (CI 0.55-0.83) for group B, while group C was taken as a reference. CONCLUSIONS: beta-Blocker therapy is beneficial in ACS and they should be started in those who are not pretreated and continued in stable patients who had been on chronic beta-blocker therapy before.
Resumo:
CONTEXT AND OBJECTIVE: The optimal strategy for inducing fertility in men with congenital hypogonadotropic hypogonadism (CHH) is equivocal. Albeit a biologically plausible approach, pretreatment with recombinant FSH (rFSH) before GnRH/human chorionic gonadotropin administration has not been sufficiently assessed. The objective of the study was to test this method. DESIGN AND SETTING: This was a randomized, open-label treatment protocol at an academic medical center. PATIENTS AND INTERVENTIONS: GnRH-deficient men (CHH) with prepubertal testes (<4 mL), no cryptorchidism, and no prior gonadotropin therapy were randomly assigned to either 24 months of pulsatile GnRH therapy alone (inducing endogenous LH and FSH release) or 4 months of rFSH pretreatment followed by 24 months of GnRH therapy. Patients underwent serial testicular biopsies, ultrasound assessments of testicular volume, serum hormone measurements, and seminal fluid analyses. RESULTS: rFSH treatment increased inhibin B levels into the normal range (from 29 ± 9 to 107 ± 41 pg/mL, P < .05) and doubled testicular volume (from 1.1 ± 0.2 to 2.2 ± 0.3 mL, P < .005). Histological analysis showed proliferation of both Sertoli cells (SCs) and spermatogonia, a decreased SC to germ cell ratio (from 0.74 to 0.35), and SC cytoskeletal rearrangements. With pulsatile GnRH, the groups had similar hormonal responses and exhibited significant testicular growth. All men receiving rFSH pretreatment developed sperm in their ejaculate (7 of 7 vs 4 of 6 in the GnRH-only group) and showed trends toward higher maximal sperm counts. CONCLUSIONS: rFSH pretreatment followed by GnRH is successful in inducing testicular growth and fertility in men with CHH with prepubertal testes. rFSH not only appears to maximize the SC population but also induces morphologic changes, suggesting broader developmental roles.
Resumo:
BACKGROUND: Infantile haemangiomas (IHs) are very common vascular tumours. Propranolol is at present the first-line treatment for problematic and complicated haemangioma. In accordance with a Swiss protocol, children are monitored for 2 days at the start of the treatment to detect possible side effects of this drug. Our study advocates a simplification of the pretreatment monitoring process. METHODS: All children with a problematic and complicated haemangioma treated with propranolol between September 2009 and September 2012 were included in the study. All patients were hospitalised under constant nurse supervision for 48 hours at the start of the treatment and subjected to cardiac and blood measurements. The dosage of propranolol was 1 mg/kg/day on the first day and 2 mg/kg/day from the second day. Demographic data, clinical features, treatment outcome and complications were analysed. RESULTS: Twenty-nine infants were included in our study. Of these, 86.2% responded immediately to the treatment. There were no severe adverse reactions. Six patients presented transient side effects such as bradycardia, hypotension after the first dose and hypoglycaemia later. No side effects occurred after the second dose. Treatment was never interrupted. CONCLUSION: Propranolol (a β-blocker) is a safe treatment for problematic IH. Side effects may occur after the first dose. A strict 48 hour monitoring in hospital is expensive and may be unnecessary as long as the contraindications for the drug are respected.
Resumo:
Background: Data from different studies suggest a favourable association between pretreatment with statins or hypercholesterolemia and outcome after ischaemic stroke. We examined whether there were differences in in-hospital mortality according to the presence or absence of statin therapy in a large population of first-ever ischaemic stroke patients and assessed the influence of statins upon early death and spontaneous neurological recovery. Methods: In 2,082 consecutive patients with first-ever ischaemic stroke collected from a prospective hospital-based stroke registry during a period of 19 years (1986-2004), statin use or hypercholesterolemia before stroke was documented in 381 patients. On the other hand, favourable outcome defined as grades 0-2 in the modified Rankin scale was recorded in 382 patients. Results: Early outcome was better in the presence of statin therapy or hypercholesterolemia (cholesterol levels were not measured) with significant differences between the groups with and without pretreatment with statins in in-hospital mortality (6% vs 13.3%, P = 0.001) and symptom-free (22% vs 17.5%, P = 0.025) and severe functional limitation (6.6% vs 11.5%, P = 0.002) at hospital discharge, as well as lower rates of infectious respiratory complications during hospitalization. In the logistic regression model, statin therapy was the only variable inversely associated with in-hospital death (odds ratio 0.57) and directly associated with favourable outcome (odds ratio 1.32).
Resumo:
BACKGROUND: Tyrosine kinase inhibitors (TKI) improve the outcome of patients with advanced gastrointestinal stromal tumour (GIST), but treatment failure is frequent, and prognosis then bleak. Smaller trials in this setting suggested activity for sorafenib, a multikinase inhibitor of receptor tyrosine kinases and RAF serine/threonine kinases. PATIENTS AND METHODS: We retrospectively evaluated the efficacy of sorafenib, starting dose 400mg twice daily, in a large community-based cohort of 124 patients treated in 12 European and one United States (U.S.) cancer centre. All but one patient had a WHO performance score 0-2. All had failed both imatinib and sunitinib, 68 patients nilotinib and 26 had failed investigational therapy, too. RESULTS: Twelve (10%) patients responded to sorafenib and 70 (57%) patients achieved disease stabilisation. Sorafenib was moderately tolerated, and toxicity reported in 56% of the patients. Rash, hand-foot-syndrome and diarrhea occurred frequently. Sorafenib dosage was reduced in a third of patients, but this did not have an impact on progression-free survival (PFS) (p=0.15). Median PFS was 6.4months (95% confidence interval [CI], 4.6-8.0months) and median overall survival (OS) 13.5months (95% CI, 10.0-21.0months). Patients with a good performance status and those who responded to sorafenib had a significant better PFS. CONCLUSION: We conclude that sorafenib is active in GIST resistant to imatinib, sunitinib and nilotinib. These results warrant further investigation of sorafenib or similar molecules in GIST.