121 resultados para THERMAL EFFECTIVENESS
Resumo:
Microencapsulation of Lippia sidoides essential oil was carried out by spray drying. Blends of maltodextrin and gum arabic were used as carrier. Spray dried microparticles were characterized using conventional (thermogravimetry, evolved gas analysis) and combined (thermogravimetry-mass spectrometry analysis) thermal analysis techniques in order to evaluate the abilities of carriers with different compositions in retaining and in releasing the core vs. dynamic heating. Thermal analysis was useful to evaluate the physico-chemical interactions between the core and carriers and to determine the protective effect of the carriers on the evaporation of essential oil.
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Polybia scutellaris constructs huge nests characterized by numerous spinal projections on the surface. We investigated the thermal characteristics of P scutellaris nests in order to determine whether their nest temperature is homeothermically maintained and whether the spines play a role in the thermoregulation of the nests. In order to examine these hypotheses, we measured the nest temperature in a active nest and in an abandoned nest. The temperature in the active nest was almost stable at 27 degrees C, whereas that of the abandoned nest varied with changes in the ambient temperature, suggesting that nest temperature was maintained by the thermogenesis of colony individuals. In order to predict the thermal properties of the spines, a numerical simulation was employed. To construct a 3D-model of a P scutellaris nest, the nest architecture was simplified into an outer envelope and the surface spines, for both of which the initial temperature was set at 27 degrees C. The physical properties of the simulated nest were regarded to be those of wood since the nest of this species is constructed from plant materials. When the model was exposed to cool air (12 degrees C), the temperature was lower in the models with more spines. On the other hand, when the nest was heated (42 degrees C), the temperature increase was smaller in models with more spines. It is suggested that the spines act as a heat radiator, not as an insulator, against the changes in ambient temperature.
Thermal Characteristics of the Mud Nests of the Social Wasp Polybia spinifex (Hymenoptera; Vespidae)
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The thermal characteristics of mud nests of Polybia spinifex were investigated by measuring internal and surface temperatures of the nests. The nests had a layer of mud envelope and consisted of mud with fine sand particles. The envelope had a vertically long slit-like entrance hole. The mud nests had high thermal conductivities (0.51-0.67 W/(m degrees C)) comparable to brick, rather than insulation materials of wasps` nests such as paper and wood. It was revealed that the long entrance radiated more heat from the thereto-image. The rate of thermal radiation (emissivity) of the nest surface was 0.80, and the value was similar to that of sand. The internal temperatures of the nests were high from top (T(n1), temperature difference between ambient temperature (T(a)) was 10 degrees C) to bottom (T(n3), difference, 5 degrees C) at noon. On the other hand, the temperature distributions were reversed during the night. Temperature T(n1) was lower by 1 degrees C than T(a), possibly from nightly dew on the top surface, whereas, at the middle point (T(n2),) and T(n3), temperatures were higher by 1 degrees C compared to T(a). Temperature fluctuations (ranges between maximum and minimum temperature) at T(n2) and T(n3) were similar to that of T(a), whereas the values at T(n1) and T(s) were higher than that of T(a).
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The electrocatalytic activity of Pt and RuO(2) mixed electrodes of different compositions towards methanol oxidation was investigated. The catalysts were prepared by thermal decomposition of polymeric precursors and characterized by energy dispersive X-ray, scanning electronic microscopy, X-ray diffraction and cyclic voltammetry. This preparation method allowed obtaining uniform films with controlled stoichiometry and high surface area. Cyclic voltammetry experiments in the presence of methanol showed that mixed electrodes decreased the potential peak of methanol oxidation by approximately 100 mV (RHE) when compared to the electrode containing only Pt. In addition, voltammetric experiments indicated that the Pt(0.6)Ru(0.4)O(y) electrode led to higher oxidation current densities at lower potentials. Chronoamperometry experiments confirmed the contribution of RuO(2) to the catalytic activity as well as the better performance of the Pt(0.6)Ru(0.4)O(y) electrode composition. Formic acid and CO(2) were identified as being the reaction products formed in the electrolysis performed at 400 and 600 mV. The relative formation of CO(2) was favored in the electrolysis performed at 400 mV (RHE) with the Pt(0.6)Ru(0.4)O(y) electrode. The presence of RuO(2) in Pt-Ru-based electrodes is important for improving the catalytic activity towards methanol electrooxidation. Moreover, the thermal decomposition of polymeric precursors seems to be a promising route for the production of catalysts applicable to DMFC. (C) 2009 International Association for Hydrogen Energy. Published by Elsevier Ltd. All rights reserved.
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Carbon-supported catalysts containing platinum and molybdenum oxide are prepared by thermal decomposition of polymeric precursors. The Pt(y)Mo(z)O(x)/C materials are characterized by energy dispersive X-ray spectroscopy, transmission electron microscopy, and X-ray diffraction. The catalysts present a well-controlled stoichiometry and nanometric particles. Molybdenum is present mainly as the MoO(3) orthorhombic structure, and no Pt alloys are detected. The voltammetric behavior of the electrodes is investigated; a correlation with literature results for PtMo/C catalysts prepared by other methods is established. The formation of soluble species and the aging effect are discussed. (C) 2009 Elsevier B.V. All rights reserved.
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BACKGROUND: Amaranth is a little-known culture in Brazilian agriculture. Amaranthus cruentus BRS Alegria was the first cultivar recommended by Embrapa for the soil of the Brazilian scrubland. In order to evaluate the potential of this species in the production of flour, starch and protein concentrates, the latter products were obtained from A. cruentus BRS Alegria seeds, characterized and compared with the products obtained from the A. caudatus species cultivated in its soil of origin. RESULTS: The seeds of A. cruentus BRS Alegria furnished high-purity starch and flour with significant content of starch, proteins, and lipids. The starch and flour of this species presented higher gelatinization temperatures and formed stronger gels upon cooling compared with those obtained from the A. caudatus species. This is due to their greater amylose content and a difference in the composition of the more important fatty acids, such as stearic, oleic and linoleic acids, which indicates that they have greater heat stability. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis and differential scanning calorimetry revealed the presence of albumins, globulins, glutelins and prolamins in the protein concentrate, which was obtained as a byproduct of starch production. CONCLUSION: Amaranthus cruentus BRS Alegria has potential application in the production of flour, starch and protein concentrates, with interesting characteristics for use as food ingredients. (C) 2010 Society of Chemical Industry
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BACKGROUND AND OBJECTIVE: To compare the analgesic effectiveness and aesthetic appearance associated with topical, subconjunctival, and peribulbar anesthesia for intravitreal bevacizumab injection. PATIENTS AND METHODS: Sixty consecutive patients undergoing their first intravitreal bevacizumab injection were randomized to receive one of three forms of anesthesia: proxymetacaine eye drops, subconjunctival injection of 2% xylocaine, and peribulbar injection of 2% xylocaine. Pain associated with the intravitreal injection and with the entire procedure (including anesthesia administration) was recorded using a Visual Analog Scale 15 minutes after intravitreal injection. Anterior segment evaluation was performed 24 hours after injection to measure the number of clock hours of subconjunctival hemorrhage. RESULTS: Median injection-related pain score was significantly lower in the peribulbar group compared with the topical and subconjunctival groups (P < .05). Median entire procedure pain score was significantly higher In the peribulbar group compared with the topical and subconjunctival groups (P < .05). The median extent of subconjunctival hemorrhage was significantly lower in the topical group compared with the other groups (P < .05). CONCLUSION: Among the three anesthetic techniques, peribulbar anesthesia was associated with greater effectiveness in controlling injection-related pain but was least effective in controlling entire procedure pain. There was no significant difference in pain scores between the topical and subconjunctival groups, and topical anesthesia was associated with less subconjunctival hemorrhage.
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Context: Isolated heterozygous SHOX defects are the most frequent monogenic cause of short stature, and combined therapy with recombinant human GH (rhGH) and GnRH analog (GnRHa) in pubertal patients has been suggested, but there are no data on final height. Objective: The aim of the study was to analyze adult height after rhGH and GnRHa therapy in patients with SHOX haploinsufficiency. Patients: Ten peripubertal patients with isolated SHOX defects participated in the study. Intervention: Five patients were followed without treatment, and five were treated with rhGH (50 mu g/kg/d) and depot leuprolide acetate (3.75 mg/month). Main Outcome Measures: Adult height SD score (SDS) was measured. Results: All patients followed without treatment had marked downward growth shift during puberty (height SDS, -1.2 +/- 0.7 at 11.4 +/- 1.4 yr; adult height SDS, -2.5 +/- 0.5). Conversely, four of five patients treated with rhGH for 2 to 4.9 yr associated to GnRHa for 1.4 to 5.8 yr improved their height SDS from -2.3 +/- 1.3 at 11.8 +/- 2.1 yr to a final height SDS of -1.7 +/- 1.6. The difference between the mean height SDS at the first evaluation and final height SDS was statistically significant in nontreated vs. treated patients (mean height SDS change, -1.2 +/- 0.4 vs. 0.6 +/- 0.4, respectively; P < 0.001). Conclusion: A gain in adult height of patients with isolated SHOX defects treated with combined rhGH and GnRHa therapy was demonstrated for the first time, supporting this treatment for children with SHOX defects who have just started puberty to avoid the loss of growth potential observed in these patients during puberty. (J Clin Endocrinol Metab 95: 328-332, 2010)
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Objective: To evaluate the usefulness of gamma-glutamyltransferase (GGT) and mean corpuscular volume (MCV), as well as that of the CAGE questionnaire, in workplace screening for alcohol abuse/dependence. Methods: A total of 183 male employees were submitted to structured interviews (Structured Clinical Interview for DSM-IV 2.0 and CAGE questionnaire). Blood samples were collected. Diagnostic accuracy and odds ratio were determined for the CAGE, GGT and MCV. Results: The CAGE questionnaire presented the best sensitivity for alcohol dependence (91%; specificity, 87.8%) and for alcohol abuse (87.5%, specificity, 80.9%), which increased when the questionnaire was used in combination with GGT (sensitivity, 100% and 87.5%, respectively; specificity, 68% and 61.5, respectively). CAGE positive results and/or alterations in GGT were less likely to occur among employees not presenting alcohol abuse/ dependence than among those presenting such abuse (OR for CAGE = 13, p < 0.05; OR for CAGE-GGT = 11, p < 0.05) or dependence (OR for CAGE = 76, p < 0.0 1; OR for GGT = 5, p < 0.0 1). Employees not presenting alcohol abuse/dependence were also several times more likely to present negative CAGE or GGT results. Conclusions: The use short, simple questionnaires, combined with that of low-cost biochemical markers, such as GGT, can serve as an initial screening for alcohol-related problems, especially for employees in hazardous occupations. The data provided can serve to corroborate clinical findings. (C) 2008 Elsevier Ltd. All rights reserved.
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Introduction. Chronic allograft vasculopathy is an important cause of graft loss. Considering the inflammatory response in the development of chronic vascular lesions, therapeutic approaches to target the inflammatory process may be useful. We sought to investigate the possible protective effects on balloon catheter-induced vascular injury of thalidomide and tamoxifen, 2 drugs with powerful anti-inflammatory, immunomodulatory, and antifibrotic effects, using an animal model that mimics the morphologic features of chronic allograft vasculopathy. Methods. Male Wistar rats subjected to balloon catheter carotid injury (INJ) were treated with thalidomide (100 mg/kg), or tamoxifen (10 mg/kg), or vehicle. Contralateral right carotid arteries were used as uninjured controls. Morphometric and immunohistochemical analyses were performed at 14 days postinjury. Results. Injured carotid arteries showed marked neointimal hyperplasia, which was significantly inhibited among animals treated with thalidomide or tamoxifen: neointimal/media ratios of 1.4 +/- 0.4 versus 0.2 +/- 0.1 versus 0.4 +/- 0.2, for INJ, INJ + Thalid, and INJ + Tamox; respectively (P < .001). The endothelial cell loss was significantly less pronounced among animals subjected to carotid balloon injury that were treated with thalidomide (24 +/- 14 vs 1 +/- 1 cells per section in INJ, respectively (P < .05). Therapy with either thalidomide or tamoxifen effectively maintained alpha-smooth muscle actin expression in the media, similar to uninjured arteries. In this setting, tamoxifen was additionally effective to prevent the migration of myofibroblasts in to the intima. Conclusion. Thalidomide and tamoxifen were effective to reduce neointimal hyperplasia secondary to vascular damage. The vasculoprotective effects of thalidomide were more pronounced to preserve endothelial cells, whereas tamoxifen inhibited smooth muscle cell migration and proliferation. A possible beneficial effect of combined therapy with thalidomide plus tamoxifen should be addressed in future studies.
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Objective. To assess the efficacy of medial-wedge insoles in valgus knee osteoarthritis (OA). Methods. Thirty consecutive women with valgus-deformity knee OA a:8 degrees were randomized into 2 groups: medial insole (insoles with B-mm medial elevation at the rearfoot [n = 161) and neutral insole (similar insole without elevation [n = 14]). Both groups also wore ankle supports. A blinded examiner assessed pain on movement, at rest, and at night with a visual analog scale (VAS), the Lequesne index., and Western Ontario and McMaster Universities Osteoarthritis (WOMAC) Index. Femorotibial, talocalcaneal, and talar tilt angles were evaluated at baseline and after 8 weeks of insole use. Results. Significant reductions in the medial insole group were observed for pain on movement (mean +/- SD VAS pre- and postintervention 8.1 +/- 1.5 versus 1 4.2 +/- 2.4; P = 0.001), at rest (5.1 +/- 2.3 versus 2.7 +/- 2.4; P = 0.002), and at night (6.1 +/- 2.7 versus 3.1 +/- 2.1; P = 0.001). In addition, a decrease in Lequesne (14.7 +/- 3.4 versus 9.6 +/- 3.8; P = 0.001) and WOMAC scores (74.1 +/- 14.2 versus 56.1 +/- 14.9; P = 0.001) was observed for the medial insole group. In the neutral insole group, a significant reduction was observed only for night pain (mean SD VAS pre- and postintervention 5.8 +/- 2.4 versus 4.6 +/- 2.4; P = 0.019). An increase in femorotibial angle (169.0 +/- 3.4 versus 170.8 +/- 2.4; P = 0.019). An increase in femorotibial angle (169.0 +/- 3.4 versus 170.8 +/- 3.7; P = 0.001) occurred only in the medial 3.7; P = 0.001) occurred only in the medial insole group. Moreover, the difference in measured fernorotibial angles pre- and postintervention was 1.84 +/- 1.42 versus -0.18 +/- 0.67 (P < 0.001) for the medial and neutral insole groups. Conclusion. The use of medial-wedge insoles was highly effective in reducing pain at rest and on movement and promoted a functional improvement of valgus knee OA.
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Background. The purpose of this study was to analyze the cost-effectiveness of cisplatin-based chemoradiation compared to radiation therapy (RT) alone to treat patients with advanced head and neck cancer in Brazil. Methods. Data were collected retrospectively from the medical records of 33 patients treated with RT alone (strategy 1) and from 29 patients treated with cisplatin-based chemoradiation (strategy 2). The Brazilian National Health System (Sistema Unico de Saude [SUS]) reimbursement parameters perspective was considered, and the effectiveness was measured in years of disease-free life gained. One-way sensitivity analysis was performed to determine robustness of this study. Results. In strategy 1, there were 31% of the patients who lived without disease progression for more than 13 months after treatment, compared to 58% of patients in strategy 2. According to SUS parameters, the total cost per patient in strategy 1 was $1167.00 U.S. dollars and in strategy 2, it was $2058.00 U.S. dollars. Incremental cost-effectiveness ratio (ICER) was $3303.00 U.S. dollars per life-year gained. Conclusion. Cisplatin-based chemoradiation proved to be more cost-effective than RT alone. (C) 2010 Wiley Periodicals, Inc. Head Neck 33: 1199-1205, 2011
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We propose a mathematical model to simulate the dynamics of hepatitis C virus (HCV) infection in the state of Sao Paulo, Brazil. We assumed that a hypothetical vaccine, which cost was taken to be the initial cost of the vaccine against hepatitis B exists and it is introduced in the model. We computed its cost-effectiveness compared with the anti-HCV therapy. The calculated basic reproduction number was 1.20. The model predicts that without intervention a steady state exists with an HCV prevalence of 3%, in agreement with the Current epidemiological data. Starting from this steady state three interventions were simulated: indiscriminate vaccination, selective vaccination and anti-HCV therapy. Selective vaccination proved to be the strategy with the best cost-effectiveness ratio, followed by indiscriminate vaccination and anti-HCV therapy.
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Introduction: Two hundred ten patients with newly diagnosed Hodgkin`s lymphoma (HL) were consecutively enrolled in this prospective trial to evaluate the cost-effectiveness of fluorine-18 ((18)F)-fluoro-2-deoxy-D-glucose-positron emission tomography (FDG-PET) scan in initial staging of patients with HL. Methods: All 210 patients were staged with conventional clinical staging (CCS) methods, including computed tomography (CT), bone marrow biopsy (BMB), and laboratory tests. Patients were also submitted to metabolic staging (MS) with whole-body FDG-PET scan before the beginning of treatment. A standard of reference for staging was determined with all staging procedures, histologic examination, and follow-up examinations. The accuracy of the CCS was compared with the MS. Local unit costs of procedures and tests were evaluated. Incremental cost-effectiveness ratio (ICER) was calculated for both strategies. Results: In the 210 patients with HL, the sensitivity for initial staging of FDG-PET was higher than that of CT and BMB in initial staging (97.9% vs. 87.3%; P < .001 and 94.2% vs. 71.4%, P < 0.003, respectively). The incorporation of FDG-PET in the staging procedure upstaged disease in 50 (24%) patients and downstaged disease in 17 (8%) patients. Changes in treatment would be seen in 32 (15%) patients. Cumulative cost for staging procedures was $3751/patient for CCS compared to $5081 for CCS + PET and $4588 for PET/CT. The ICER of PET/CT strategy was $16,215 per patient with modified treatment. PET/CT costs at the beginning and end of treatment would increase total costs of HL staging and first-line treatment by only 2%. Conclusion: FDG-PET is more accurate than CT and BMB in HL staging. Given observed probabilities, FDG-PET is highly cost-effective in the public health care program in Brazil.
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Purpose To assess the cost effectiveness of fluorine-18-fluorodeoxyglucose positron emission tomography (FDG-PET) in patients with Hodgkin`s lymphoma (HL) with unconfirmed complete remission (CRu) or partial remission (PR) after first-line treatment. Patients and Methods One hundred thirty patients with HL were prospectively studied. After treatment, all patients with CRu/PR were evaluated with FDG-PET. In addition, PET-negative patients were evaluated with standard follow-up, and PET-positive patients were evaluated with biopsies of the positive lesions. Local unit costs of procedures and tests were evaluated. Cost effectiveness was determined by evaluating projected annual economic impact of strategies without and with FDG-PET on HL management. Results After treatment, CRu/PR was observed in 50 (40.0%) of the 127 patients; the sensitivity, specificity, and positive and negative predictive values of FDG-PET were 100%, 92.0%, 92.3%, and 100%, respectively (accuracy of 95.9%). Local restaging costs without PET were $350,050 compared with $283,262 with PET, a 19% decrease. The incremental cost-effectiveness ratio is -$3,268 to detect one true case. PET costs represented 1% of total costs of HL treatment. Simulated costs in the 974 patients registered in the 2008 Brazilian public health care database showed that the strategy including restaging PET would have a total program cost of $56,498,314, which is $516,942 less than without restaging PET, resulting in a 1% cost saving. Conclusion FDG-PET demonstrated 95.9% accuracy in restaging for patients with HL with CRu/PR after first-line therapy. Given the observed probabilities, FDG-PET is highly cost effective and would reduce costs for the public health care program in Brazil.