76 resultados para Continuous improvement
Resumo:
Carbon dioxide released from alcoholic fermentation accounts for 33% of the whole CO(2) involved in the use of ethanol as fuel derived from glucose. As Arthrospira platensis can uptake this greenhouse gas, this study evaluates the use of the CO(2) released from alcoholic fermentation for the production of Arthrospira platensis. For this purpose, this cyanobacterium was cultivated in continuous process using urea as nitrogen source, either using CO(2) from alcoholic fermentation, without any treatment, or using pure CO(2) from cylinder. The experiments were carried out at 120 mu mol photons m(-2) s(-1) in tubular photobioreactor at different dilution rates (0.2 <= D <= 0.8 d(-1)). Using CO(2) from alcoholic fermentation, maximum steady-state cell concentration (2661 +/- 71 mg L(-1)) was achieved at D 0.2 d(-1), whereas higher dilution rate (0.6 d(-1)) was needed to maximize cell productivity (839 mg L(-1) d(-1)). This value was 10% lower than the one obtained with pure CO(2), and there was no significant difference in the biomass protein content. With D 0.8 d(-1), it was possible to obtain 56% +/- 1.5% and 50% +/- 1.2% of protein in the dry biomass, using pure CO(2) and CO(2) from alcoholic fermentation, respectively. These results demonstrate that the use of such cost free CO(2) from alcoholic fermentation as carbon source, associated with low cost nitrogen source, may be a promising way to reduce costs of continuous cultivation of photosynthetic microorganisms, contributing at the same time to mitigate the greenhouse effect. (C) 2011 American Institute of Chemical Engineers Biotechnol. Prog., 27: 650-656, 2011
Resumo:
The ascorbate oxidase is the enzyme used to determine the content of ascorbic acid in the pharmaceutical and food industries and clinics analyses. The techniques currently used for the purification of this enzyme raise its production cost. Thus, the development of alternative processes and with the potential to reduce costs is interesting. The application of aqueous two-phase system is proposed as an alternative to purification because it enables good separation of biomolecules. The objective of this study was to determine the conditions to continuously pre-purify the enzyme ascorbate oxidase by an aqueous two-phase system (PEG/citrate) using rotating column provided with perforated discs. Under the best conditions (20,000 g/mol PEG molar mass, 10% PEG concentration, and 25% citrate concentration), the system showed satisfactory results (partition coefficient, 3.35; separation efficiency, 54.98%; and purification factor, 1.46) and proved suitable for the pre-purification of ascorbate oxidase in continuous process.
Resumo:
A 2(3-1) factorial experimental design was used to evaluate the performance of a perforated rotating disc contactor to extract alpha-toxin from the fermented broth of Clostridium perfringens Type A by aqueous two-phase system of polyethylene glycol-phosphate salts. The influence of three independent variables, specifically the dispersed phase flowrate, the continuous phase flowrate and the disc rotational speed, was investigated on the hold up, the mass transfer coefficient, the separation efficiency and the purification factor, taken as the response variables. The optimum dispersed phase flowrate was 3.0 mL/min for all these responses. Besides, maximum values of hold up (0.80), separation efficiency (0. 10) and purification factor (2.4) were obtained at this flowrate using the lowest disc rotational speed (35 rpm), while the optimum mass transfer coefficient (0. 165 h(-1)) was achieved at the highest agitation level (140 rpm). The results of this study demonstrated that the dispersed phase flowrate strongly influenced the performance of PRDC, in that both the mass transfer coefficient and hold up increased with this parameter. (c) 2007 Elsevier B. V. All rights reserved.
Resumo:
The prominent nitric oxide (NO) donor [Ru(terpy)(bdqi)NO](PF(6))(3) has been synthesized and evaluated with respect to noteworthy biological effects due to its NO photorelease, including vascular relaxation and melanoma cell culture toxicity. The potential for delivering NO in therapeutic quantities is tenable since the nitrosyl ruthenium complex (NRC) must first reach the ""target tissue"" and then release the NO upon stimulus. In this context. NRC-loaded lipid carriers were developed and characterized to further explore its topical administration for applications such as skin cancer treatment. NRC-loaded solid lipid nanoparticles (SLN) and nanostructured lipid carriers were prepared via the microemulsification method, with average diameters of 275 +/- 15 nm and 211 +/- 31 nm and zeta potentials of -40.7 +/- 10.4 mV and -50.0 +/- 7.5 mV, respectively. In vitro kinetic studies of NRC release from nanoparticles showed sustained release of NRC from the lipid carriers and illustrated the influence of the release medium and the lyophilization process. Stability studies showed that NO is released from NRC as a function of temperature and time and due to skin contact. The encapsulation of NRC in SLN followed by its lyophilization, significantly improved the complex stability. Furthermore, of particular interest was the fact that in the NO photorelease study, the NO release from the NRC-loaded SLN was approximately twice that of just NRC in solution. NRC-loaded SLN performs well enough at releasing and protecting NO degradation in vitro that it is a promising carrier for topical delivery of NO. (C) 2010 Elsevier B.V. All rights reserved.
Resumo:
The population structure, reproductive period, and juvenile recruitment of Panopeus americanus were studied in order to enhance knowledge of its life cycle and reproductive strategy and promote the maintenance of its natural stocks in an impacted region. Specimens were collected in the remnant human-impacted mangrove at Araca, state of Sao Paulo, Brazil, at two-month intervals from January to November 2005, at low tide, with a capture effort by three people. The crabs were measured (carapace width, CW) and sexed. The total catch was 275 animals, including 132 males (48.0%); 127 females (46.2%), of which 39 were ovigerous (14.2% of total catch); and 16 individuals whose sex could not be identified (5.8%). No correlation was observed between water temperature and the number of collected individuals; however, there was a significant, positive correlation with salinity. Males were significantly larger than females. The size-frequency distribution was bimodal, reflecting the occurrende of more than one recruitment pulse and the differential abundance of adults during the period of study. The overall sex ratio was 1:0.97 favoring males, and was not significantly different from the expected value, i.e., this population fits the anomalous pattern of sex occurrence in size classes. Ovigerous females were captured in all sampled months, which explain the continuous recruitment observed. Expected low levels of individuals of different size classes in the population were not confirmed. All population aspects found here allowed us to infer that this population of P. americanus is well established in the impacted mangrove by virtue of its reproductive strategy.
Resumo:
Bariatric surgery in morbidly obese type 2 diabetic (T2DM) patients is associated with high rates of diabetes remission. We investigated the mechanisms of the anti-diabetic effect of the laparoscopic ileal interposition with sleeve gastrectomy (LII-SG) in normal weight (NW), overweight (OW) and obese (OB) T2DM patients. Ninety-four patients (aged 54 +/- 8 years) with long-standing (median 10 years), treated diabetes (median HbA(1c) = 8.6%), who were NW (15), OW (64) or OB (15) based on BMI, underwent LII-SG. Insulin sensitivity and parameters of -cell function were measured from an Oral Glycaemic Tolerance Test pre- and post-operatively. At a median of 13.4 months post-operatively, weight loss averaged 9.4 +/- 1.3, 16.8 +/- 0.8 and 23.2 +/- 1.7 kg in NW, OW and OB subjects, respectively (p < 0.0001). Insulin sensitivity was fully restored (395 [108] vs 208 [99] ml min(-1) m(-2)), fasting insulin secretion rate decreased (68 [52] vs 146 [120] pmol min(-1) m(-2)) and total insulin output increased (52 [26] vs 39 [28] nmol m(-2), all p a parts per thousand currency signaEuro parts per thousand 0.001). -cell glucose sensitivity doubled (37 [33] vs 18 [24] mol min(-1) m(-2) mM(-1), p < 0.0001). The only parameter predicting remission of diabetes was a lower baseline insulin sensitivity (p = 0.005). LII-SG induced changes on T2DM by mechanisms in part distinct from weight loss, principally involving restoration of insulin sensitivity and improvement of -cell function.
Resumo:
Background: The objective of this study was to compare bleeding patterns of women using a contraceptive combination of 30 mcg ethinylestradiol (EE) and 3 mg drospirenone (DRSP) continuously or cyclically. Menstrual-related symptoms were also evaluated. Study Design: This open, prospective, randomized study evaluated 78 women using the EE/DRSP combination continuously for 168 days or for six 28-day cycles, each followed by a 7-day hormone-free interval. A diary with pre-established scales was used to assess the frequency and intensity of bleeding and menstrual-related symptoms. Results: Amenorrhea increased with continuous use; 62.2% of women with continuous use were amenorrheic at the end of treatment (95% CI: 46.6-77.8%). Dysmenorrhea, headache, acne, nausea, edema and increased appetite improved significantly in the continuous-use group, and mastalgia and edema in the cyclic-use group (p<.05). Six subjects in the continuous-use group (15.4%) and three in the cyclic-use group (7.7%) discontinued due to adverse events. Conclusions: Continuous use was associated with amenorrhea and fewer menstrual-related symptoms compared to cyclic use. (C) 2010 Elsevier Inc. All rights reserved.
Resumo:
Background: The objective of this study was to evaluate the effects of a contraceptive pill containing ethinylestradiol (30 mcg) and drospirenone (3 mg) in a continuous regimen on lipid, carbohydrate and coagulation parameters. Study Design: This open, prospective, randomized study included 78 participants (mean age 27.8 years) who were randomized into two groups to use the pill continuously for 168 days or for six 28-day cycles with a 7-day hormone-free interval between cycles. Markers of lipid, carbohydrate and coagulation profiles were measured prior to initiation and after the 6 months of pill use. Results: No statistically significant differences were found between the two contraceptive regimens with respect to carbohydrate or lipid profiles or in the parameters related to coagulation. Conclusions: The contraceptive combination of ethinylestradiol and drospirenone used in a continuous regimen was associated with metabolic alterations similar to those found during the traditional cyclic regimen of oral contraceptive use. (C) 2010 Elsevier Inc. All rights reserved.
Resumo:
Background: Obesity and obstructive sleep apnea (OSA) are both associated with the prevalence of major cardiovascular illnesses and certain common factors they are considered responsible for, such as stress oxidative increase, sympathetic tonus and resistance to insulin. Objective: The aim of the present study was to compare the effect of continuous positive airway pressure (CPAP) on oxidative stress and adiponectin levels in obese patients with and without OSA. Methods: Twenty-nine obese patients were categorized into 3 groups: group 1: 10 individuals without OSA (apnea-hypopnea index, AHI <= 5) who did not have OSA diagnosed at polysomnography; group 2: 10 patients with moderate to severe OSA (AHI >= 20) who did not use CPAP; group 3: 9 patients with moderate to severe OSA (AHI >= 20) who used CPAP. Results: Group 3 showed significant differences before and after the use of CPAP, in the variables of diminished production of superoxide, and increased nitrite and nitrate synthesis and adiponectin levels. Positive correlations were seen between the AHI and the superoxide production, between the nitrite and nitrate levels and the adiponectin levels, between superoxide production and the HOMA-IR, and between AHI and the HOMA-IR. Negative correlations were found between AHI and the nitrite and nitrate levels, between the superoxide production and that of nitric oxide, between the superoxide production and the adiponectin levels, between AHI and the adiponectin levels, and between the nitrite and nitrate levels and the HOMA-IR. Conclusions: This study demonstrates that the use of CPAP can reverse the increased superoxide production, the diminished serum nitrite, nitrate and plasma adiponectin levels, and the metabolic changes existing in obese patients with OSA. Copyright (C) 2009 S. Karger AG, Basel
Resumo:
Objectives: To describe current practice for the discontinuation of continuous renal replacement therapy in a multinational setting and to identify variables associated with successful discontinuation. The approach to discontinue continuous renal replacement therapy may affect patient outcomes. However, there is lack of information on how and under what conditions continuous renal replacement therapy is discontinued. Design: Post hoc analysis of a prospective observational study. Setting. Fifty-four intensive care units in 23 countries. Patients: Five hundred twenty-nine patients (52.6%) who survived initial therapy among 1006 patients treated with continuous renal replacement therapy. Interventions: None. Measurements and Main Results., Three hundred thirteen patients were removed successfully from continuous renal replacement therapy and did not require any renal replacement therapy for at least 7 days and were classified as the ""success"" group and the rest (216 patients) were classified as the ""repeat-RRT"" (renal replacement therapy) group. Patients in the ""success"" group had lower hospital mortality (28.5% vs. 42.7%, p < .0001) compared with patients in the ""repeat-RRT"" group. They also had lower creatinine and urea concentrations and a higher urine output at the time of stopping continuous renal replacement therapy. Multivariate logistic regression analysis for successful discontinuation of continuous renal replacement therapy identified urine output (during the 24 hrs before stopping continuous renal replacement therapy: odds ratio, 1.078 per 100 mL/day increase) and creatinine (odds ratio, 0.996 per mu mol/L increase) as significant predictors of successful cessation. The area under the receiver operating characteristic curve to predict successful discontinuation of continuous renal replacement therapy was 0.808 for urine output and 0.635 for creatinine. The predictive ability of urine output was negatively affected by the use of diuretics (area under the receiver operating characteristic curve, 0.671 with diuretics and 0.845 without diuretics). Conclusions. We report on the current practice of discontinuing continuous renal replacement therapy in a multinational setting. Urine output at the time of initial cessation (if continuous renal replacement therapy was the most important predictor of successful discontinuation, especially if occurring without the administration of diuretics. (Crit Care Med 2009; 37:2576-2582)
Resumo:
Despite modern reanimation surgical techniques, facial paralysis presents with functional and aesthetic deficits. We evaluated facial symmetry after treating with botulinum toxin the healthy side of the face of 25 patients with long-standing facial paralysis who had previously been treated by surgical methods, with 6 months follow-up. Evaluation consisted of a clinical score, the two subscales of the Facial Disability Index, and surface electromyography. The mean botulinum toxin dose was 38 +/- A 5 U (range = 15-69 U). The clinical score showed significant reduction of asymmetry of 48.4% at 1 month and 16.8% after 6 months. The initial result was a consequence of reduced motion on the treated side combined with better motion on the paralyzed side. At 6 months, the treated side returned to basal scores. The residual effect seen in symmetry was due to an increase (18%) of motion in the paralyzed side. There was a significant decrease in the action potential of muscles on the nonparalyzed side 1 month post injection but completely reverted after 6 months. The Physical Function Index increased, but not significantly. The Social/Well-Being Function Index showed a significant increase at 6 months compared to pretreatment. The proposed treatment improved facial symmetry for up to 6 months. Even after the end of the clinical effect of the drug, the paralyzed side`s clinical score was 18% higher than pretreatment, with an increased quality of life.
Resumo:
Objective: Physical and psychological incapacity, including fear of falling is related to decreased satisfaction with life in osteoporosis (OP). The impact of a balance exercise program on improving the quality of life is not well established. We have, therefore, investigated the effect of 12-month Balance Training Program in quality of life, functional balance and falls in elderly OP women. Methods: Sixty consecutive women with senile OP were randomized into a Balance Training Group (BT) of 30 patients and no intervention control group (CG) of 30 patients. The BT program included techniques to improve balance over a period of 12 months (1 h exercise session/week and home-based exercises). The quality of life was evaluated before and at the end of the trial using the Osteoporosis Assessment Questionnaire (OPAQ), functional balance was evaluated by Berg Balance Scale (BBS). Falls in the preceding year were noted and compared to the period of study. Results: The comparison of OPAQ variations (INITIAL-FINAL) revealed a significant improvement in quality of life in all parameters for BT compared to CG: well-being (1.61 +/- 1.44 vs. -1.46 +/- 1.32, p < 0001), physical function (1.30 +/- 1.33 vs. -0.36 +/- 0.82, p < 0.001), psychological status (1.58 +/- 1.36 vs. -1.02 +/- 0.83, p < 0.001), symptoms (2.76 +/- 1.96 vs. -0.63 +/- 0.87, p < 0.001), social interaction (1.01 +/- 1.51 vs. 0.35 +/- 1.08, p < 0.001). Of note, this overall benefit was paralleled by an improvement of BBS (-5.5 +/- 5.67 vs. +0.5 +/- 4.88 p < 0.001) and a reduction of falls in 50% in BT group vs. 26.6% for the CG (RR: 1.88, p < 0.025). Conclusion: The long-term Balance Training Program of OP women provides a striking overall health quality of life improvement in parallel with improving functional balance and reduced falls. (C) 2010 Elsevier Ireland Ltd. All rights reserved.
Resumo:
Exercise is an effective intervention for treating hypertension and arterial stiffness, but little is known about which exercise modality is the most effective in reducing arterial stiffness and blood pressure in hypertensive subjects. Our purpose was to evaluate the effect of continuous vs. interval exercise training on arterial stiffness and blood pressure in hypertensive patients. Sixty-five patients with hypertension were randomized to 16 weeks of continuous exercise training (n=26), interval training (n=26) or a sedentary routine (n=13). The training was conducted in two 40-min sessions a week. Assessment of arterial stiffness by carotid-femoral pulse wave velocity (PWV) measurement and 24-h ambulatory blood pressure monitoring (ABPM) were performed before and after the 16 weeks of training. At the end of the study, ABPM blood pressure had declined significantly only in the subjects with higher basal values and was independent of training modality. PWV had declined significantly only after interval training from 9.44 +/- 0.91 to 8.90 +/- 0.96 m s(-1), P=0.009 (continuous from 10.15 +/- 1.66 to 9.98 +/- 1.81 m s(-1), P-ns; control from 10.23 +/- 1.82 to 10.53 +/- 1.97 m s(-1), P-ns). Continuous and interval exercise training were beneficial for blood pressure control, but only interval training reduced arterial stiffness in treated hypertensive subjects. Hypertension Research (2010) 33, 627-632; doi:10.1038/hr.2010.42; published online 9 April 2010
Resumo:
Background-Prasugrel is a novel thienopyridine that reduces new or recurrent myocardial infarctions (MIs) compared with clopidogrel in patients with acute coronary syndrome undergoing percutaneous coronary intervention. This effect must be balanced against an increased bleeding risk. We aimed to characterize the effect of prasugrel with respect to the type, size, and timing of MI using the universal classification of MI. Methods and Results-We studied 13 608 patients with acute coronary syndrome undergoing percutaneous coronary intervention randomized to prasugrel or clopidogrel and treated for 6 to 15 months in the Trial to Assess Improvement in Therapeutic Outcomes by Optimizing Platelet Inhibition With Prasugrel-Thrombolysis in Myocardial Infarction (TRITON-TIMI 38). Each MI underwent supplemental classification as spontaneous, secondary, or sudden cardiac death (types 1, 2, and 3) or procedure related (Types 4 and 5) and examined events occurring early and after 30 days. Prasugrel significantly reduced the overall risk of MI (7.4% versus 9.7%; hazard ratio [HR], 0.76; 95% confidence interval [CI], 0.67 to 0.85; P < 0.0001). This benefit was present for procedure-related MIs (4.9% versus 6.4%; HR, 0.76; 95% CI, 0.66 to 0.88; P = 0.0002) and nonprocedural (type 1, 2, or 3) MIs (2.8% versus 3.7%; HR, 0.72; 95% CI, 0.59 to 0.88; P = 0.0013) and consistently across MI size, including MIs with a biomarker peak >= 5 times the reference limit (HR. 0.74; 95% CI, 0.64 to 0.86; P = 0.0001). In landmark analyses starting at 30 days, patients treated with prasugrel had a lower risk of any MI (2.9% versus 3.7%; HR, 0.77; P = 0.014), including nonprocedural MI (2.3% versus 3.1%; HR, 0.74; 95% CI, 0.60 to 0.92; P = 0.0069). Conclusion-Treatment with prasugrel compared with clopidogrel for up to 15 months in patients with acute coronary syndrome undergoing percutaneous coronary intervention significantly reduces the risk of MIs that are procedure related and spontaneous and those that are small and large, including new MIs occurring during maintenance therapy. (Circulation. 2009; 119: 2758-2764.)
Resumo:
Background: Despite antihypertensive therapy, it is difficult to maintain optimal systemic blood pressure (BP) values in hypertensive patients (HPT). Exercise may reduce BP in untreated HPT. However, evidence regarding its effect in long-term antihypertensive therapy is lacking. Our purpose was to evaluate the acute effects of 40-minute continuous (CE) or interval exercise (IE) using cycle ergometers on BP in long-term treated HPT. Methods: Fifty-two treated HPT were randomized to CE (n=26) or IE (n=26) protocols. CE was performed at 60% of reserve heart rate (HR). IE alternated consecutively 2 min at 50% reserve HR with 1 min at 80%. Two 24-h ambulatory BP monitoring were made after exercise (postexercise) or a nonexercise control period (control) in random order. Results: CE reduced mean 24-h systolic (S) BP (2.6 +/- 6.6 mm Hg, p-0.05) and diastolic (D) BP (2.3 +/- 4.6, p-0.01), and nighttime SBP (4.8 +/- 6.4, p < 0.001) and DBP (4.6 +/- 5.2 mm Hg, p-0.001). IE reduced 24-h SBP (2.8 +/- 6.5, p-0.03) and nighttime SBP (3.4 +/- 7.2, p-0.02), and tended to reduce nighttime DBP (p=0.06). Greater reductions occurred in higher BP levels. Percentage of normal ambulatory BP values increased after CE (24-h: 42% to 54%; daytime: 42% to 61%; nighttime: 61% to 69%) and IE (24-h: 31% to 46%; daytime: 54% to 61%; nighttime: 46% to 69%). Conclusion: CE and IE reduced ambulatory BP in treated HPT, increasing the number of patients reaching normal ambulatory BP values. These effects suggest that continuous and interval aerobic exercise may have a role in BP management in treated HPT. (c) 2008 Elsevier Ireland Ltd. All rights reserved.