869 resultados para Effect of surface active agents on rubber filter interaction
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This study was conducted to evaluate the morphologic modifications in tissues of the fruit and seed of the crambe (Crambe abyssinica Hochst. Ex R.E. Fr.) after drying at different temperatures. Fruits with a water content of 0.38 kg water/kg dry matter were harvested and manually homogenized. Drying was accomplished at 35, 45, 60, 75, and 90°C and at 21,9,7,5, and 2% relative humidity, respectively. After drying, the structure of the pericarp and tegument of the seed were evaluated and the embryo was removed from the fruit/seed for morphological analysis (structural and ultrastructural and the histolocalization of reserve substances). Drying at different temperatures did not affect the cellular structure of the tissues composing the pericarp of the fruits, but it disorganized the structure of the seed tegument. The cells of the tegument and cotyledons presented a contraction in their volumes. The lowest contractions in the cellular volumes of both the tegument and cotyledons occurred after drying at 35 and 45°C. The cytoplasm of the cotyledon cells contains oil drops and the protein bodies contain protein granules and starch grains. There were no changes in the cellular walls of the embryos of the fruits dried at different temperatures; however, ungluing of the medium lamella occurred. This damage occurred with greater intensity after drying at temperatures above 60°C. The form of the oil drops in the cytoplasm of the cotyledon cells was altered after drying. At temperatures above 60°C, the drops broke up and coalesced. After drying at 45 and 60°C, the form of some protein bodies was altered, whereas at 75 and 90°C coalescence of the protein bodies occurred in some cells. It was concluded that the identified alterations can affect the physiologic quality of crambe seeds. © 2013 Copyright Taylor and Francis Group, LLC.
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This ex vivo study evaluated the antibacterial effect of intracanal medications in root canals contaminated with Enterococcus faecalis. Fifty single-rooted human teeth were contaminated with E. faecalis (ATCC 29212) and incubated at 37°C for 21 days. The specimens were randomly divided into 5 groups according to the intracanal medication used: OZ-PG: ozonized propylene glycol; CH/CPMC: calcium hydroxide/camphorated paramonochlorophenol; OZ-PG/CH ozonized PG/CH; PC: positive control group (no medication); and NC: negative control group (no contamination). The samples were collected after 7 days (post-medication) and 14 days (final). Bacterial growth was checked by counting the colony-forming units (CFU). OZ-PG and CH/CPMC reduced significantly the CFU counts compared with PC in the post-medication and final samples, with no statistically significant differences among them. On the other hand, OZ-PG/CH did not reduce significantly the number of bacteria compared with PC. In conclusion, among the evaluated medications OZ-PG and CH/CPMC were the most effective against E. faecalis.
The effect of locked screw angulation on the biomechanical properties of the S.P.S. Free-Block plate
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Objectives: Among the locked internal fixators is one denominated S.P.S. (Synthesis Pengo System) Free-Block, which was designed with a locking ring that allows the screw to be locked and positioned obliquely. Due to the paucity of biomechanical studies on this system, the present work aimed to evaluate the influence of locked screw angulation on the resistance of the S.P.S. Free--Block plate. Methods: Forty synthetic bone cylinders with 10 mm fracture gap were used. Forty seven-hole 3.5 mm stainless steel plates (two AO-like dynamic compression holes and five locked holes) were assembled according to the orientation of the locked screws: mono cortical screws were positioned at 90° to the long axis of the cylinder (Group 1), and monocortical screws were positioned at 70° to its cylinder long axis (Group 2). In both groups, AO-like dynamic compression hole screws were positioned bicortically and neutrally. For each group, six specimens were tested until failure, three in bending and three in compression, to determine the loads for fatigue testing. Subsequently, for each group, 14 specimens were tested for failure --seven by bending and seven in compression. Results: No significant failure differences were observed between Groups 1 and 2 under static-loading or fatigue test. Clinical significance: In a fracture gap model the orientation of the locked monocortical screws did not show any influence on the mechanical performance of the S.P.S. Free-Block to tests of axial compression and four-point bending. © Schattauer 2013.
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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Some manufacturers have recently added specific components to improve the ease of handling and insertion material properties of MTA in order to create MTA-based sealers. Objective: The aim of this study was to evaluate the healing of periapical lesions in canine teeth after a single session of endodontic treatment with MTA Fillapex® compared with Sealapex® or Endo-CPM-Sealer®. Material and Methods: Sixty-two root canals were performed on two 1-year-old male dogs. After coronal access and pulp extirpation, the canals were exposed to the oral cavity for 6 months in order to induce periapical lesions. The root canals were prepared, irrigated with a solution of 2.5% sodium hypochlorite and filled with gutta-percha and different sealers, according to the following groups: 1) Sealapex®; 2) Endo-CPM-Sealer®; and 3) MTA Fillapex®. Some teeth with periapical lesions were left untreated for use as positive controls. Healthy teeth were used as negative controls. After 6 months, the animals were sacrificed and serial sections from the roots were prepared for histomorphologic analysis and stained with hematoxylin and eosin and the Brown and Brenn technique. The lesions were scored according to pre-established histomorphologic parameters and the scores statistically analyzed using the Kruskal-Wallis test. Results: All 3 materials produced similar patterns of healing (p>0.05); in particular, persistent inflammation and absence of complete periapical tissue healing were consistently noted. Conclusions: Preparation of the infected root canals followed by filling with the materials studied was insufficient to provide complete healing of the periapical tissues.
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Accumulating evidence suggests an association between body volume overload and inflammation in chronic kidney diseases. The purpose of this study was to evaluate the effect of dialysate sodium concentration reduction on extracellular water volume, blood pressure (BP), and inflammatory state in hemodialysis (HD) patients. In this prospective controlled study, adult patients on HD for at least 90 days and those with C-reactive protein (CRP) levels ≥ 0.7 mg/dL were randomly allocated into two groups: group A, which included 29 patients treated with reduction of dialysate sodium concentration from 138 to 135 mEq/L; and group B, which included 23 HD patients not receiving dialysate sodium reduction (controls). Of these, 20 patients in group A and 18 in group B completed the protocol study. Inflammatory, biochemical, hematological, and nutritional markers were assessed at baseline and after 8 and 16 weeks. Baseline characteristics were not significantly different between the two groups. Group A showed a significant reduction in serum concentrations of tumor necrosis factor-α, and interleukin-6 over the study period, while the BP and extracellular water (ECW) did not change. In Group B, there were no changes in serum concentrations of inflammatory markers, BP, and ECW. Dialysate sodium reduction is associated with attenuation of the inflammatory state, without changes in the BP and ECW, suggesting inhibition of a salt-induced inflammatory response. Copyright © 2013 Informa Healthcare USA, Inc.
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Chitosan-DNA nanoparticles employed in gene therapy protocols consist of a neutralised, stoichiometric core and a shell of the excess of chitosan which stabilises the particles against further coagulation. At low ionic strength, these nanoparticles possess a high stability; however, as the ionic strength increases, it weakens the electrostatic repulsion which can play a decisive part in the formation of highly aggregated particles. In this study, new results about the effect of ionic strength on the colloidal stability of chitosan-DNA nanoparticles were obtained by studying the interaction between chitosans of increasing molecular weights (5, 10, 16, 29, 57 and 150 kDa) and calf thymus DNA. The physicochemical properties of polyplexes were investigated by means of dynamic light scattering, static fluorescence spectroscopy, optic microscopy, transmission electronic microscopy and gel electrophoresis. After subsequent addition of salt to the nanoparticles solution, secondary aggregation increased the size of the polyplexes. The nanoparticles stability decreased drastically at the ionic strengths 150 and 500 mM, which caused the corresponding decrease in the thickness of the stabilising shell. The morphologies of chitosan/DNA nanoparticles at those ionic strengths were a mixture of large spherical aggregates, toroids and rods. The results indicated that to obtain stable chitosan-DNA nanoparticles, besides molecular weight and N/P ratio, it is quite important to control the ionic strength of the solution. © 2013 Copyright Taylor and Francis Group, LLC.
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The objective of this study was to evaluate the effect of betaine in methionine- and choline-reduced diets fed to broilers submitted to heat stress. In total, 1,408 male broilers were randomly distributed into eight treatments, according to 2 × 4 (environment x diet) factorial arrangement, with eight replicates of 2 birds each. Birds were reared environmental chambers under controlled temperature (25-26 °C) or cyclic heat-stressing temperature (25-31 °C). The following diets were tested: positive control (PC), formulated to meet broiler nutritional requirements; negative control (NC), with reduced DL-methionine and choline chloride levels; and with two supplementation levels of natural betaine to the negative control diet (NC+NB1 and NC+NB2). Live performance, carcass traits, and intestinal morphometrics were evaluated when broilers were 45 days of age. The results showed that all evaluated parameters were influenced by the interaction between environment and diet, except for breast meat drip loss. The breakdown of the interactions showed that birds fed the PC diet and reared in the controlled environment had greater breast drip loss than those submitted to the cyclic heat-stress environment. Birds submitted to cyclic heat stress and fed the PC diet presented the lowest feed intake. Feed conversion ratio was influenced only by diet. The FCR of broilers fed the NC+NB2 diet was intermediate relative to those fed the PC and NC diets. The addition of betaine in the diet, with 11.18% digestible methionine and 24.73% total choline reductions, did not affect broiler live performance, carcass yield, or intestinal morphometrics.
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The aim of the present study was to evaluate the antimicrobial effect of antimicrobial photodynamic therapy (aPDT) in alveolar treatment of areas with induced periodontitis. Thirty male Wistar rats were subjected to ligature-induced periodontal disease (PD) in the first left inferior molars, while the right side molars did not receive ligatures. After 7 days of PD evolution, ligatures were removed from the left side, and the first left and right mandibular molars were extracted. Afterwards, animals were divided into groups according to the following treatments: control (C)-no treatment; mechanical debridement (MD)-mechanical debridement and irrigation with saline solution; and aPDT-mechanical debridement, irrigation with toluidine blue O (TBO), and 1 min of laser irradiation (GaAlAs, 660 nm, 30 mW, 32 J/cm2, 60 s). Ligatures were removed and samples of the alveolar content after extraction and after each treatment were collected for microbial processing by real-time polymerase chain reaction with specific primers for Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis, and Treponema denticola. Data were submitted to statistical analysis by multiple comparison tests (McNemar test; p < 0.05). T. denticola was not found in the collected samples. A. actinomycetemcomitans and P. gingivalis were found in ligature samples. Tooth socket samples without periodontitis induction presented lesser microbial charge than samples with induced periodontitis (p < 0.05). aPDT significantly reduced A. actinomycetemcomitans levels on the left side (p < 0.05). It was concluded that aPDT was an effective antimicrobial treatment for tooth sockets in areas affected by induced periodontitis. © 2013 Springer-Verlag London.
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The aim of this study was to evaluate the effect of final irrigation protocols (17% EDTA, BioPure MTAD, SmearClear, and QMiX) on microhardness and erosion of root canal dentin. Fifty roots were sectioned transversely at the cement-enamel junction and each root was sectioned horizontally into 4-mm-thick slices. The samples were divided into five groups (n=10) according to the final irrigation protocol: G1: distilled water (control group); G2: 17% EDTA; G3: BioPure MTAD; G4: SmearClear; and G5: QMiX. The dentin microhardness was then measured with a load of 25 g for 10 s. Initially, the reference microhardness values were obtained for the samples without any etching. The same samples were then submitted to the final irrigation protocols. A new measure was realized and the difference between before and after the procedures was the dentin microhardness reduction. In sequence, the specimens were submitted to SEM analysis to verify the dentinal erosion. The Kruskal Wallis and Dunn tests (α=5%) were used to compare the results. The dentin microhardness decreased for all final irrigation protocols. There was no significant difference between groups 2, 3, 4, and 5 (P>0.05), but this groups presented significant dentin microhardness reduction than G1 (P<0.05). In G2, occurred the highest incidence of dentinal erosion (P<0.05). 17% EDTA, BioPure MTAD, SmearClear, and QMiX promoted significant dentin microhardness reduction. © 2013 Wiley Periodicals, Inc.
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We evaluated the effects of constant low-temperature storage on Diaeretiella rapae (McIntosh) (Braconidae, Aphidiinae). Diaeretiella rapae mummies were stored at 5 ± 1°C for 0-36 days. The percentage of D. rapae emergence varied (100-83%) after 0-32 days of storage. After 32 days, emergence reduced to 55%. According to our Probit analysis, 50% mortality (LT50) of the population of D. rapae was reached after 40 days of storage at 5°C. Storage for up to 32 days did not negatively affect emergence and survival. Cold exposure of D. rapae for 36 days did not influence morphological malformations, sex ratio, and emergence of the F1 generation. After 4-36 days of storage, D. rapae showed a gradual decrease in emergence, longevity, reproductive capacity, and F1 sex ratio. Diaeretiella rapae can be stored for up to 24 days at 5°C, at which time the percentage of parasitism and the F1 sex ratio remain above 38% and at 0.50, respectively. © 2013 Sociedade Entomológica do Brasil.
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Objective The objective was to examine the effect of a solvent dimethyl sulfoxide (DMSO) on resin-dentin bond durability, as well as potential functional mechanisms behind the effect. Methods Microtensile bond strength (μTBS) was evaluated in extracted human teeth in two separate experiments. Dentin specimens were acid-etched and assigned to pre-treatment with 0.5 mM (0.004%) DMSO as additional primer for 30 s and to controls with water pre-treatment. Two-step etch-and-rinse adhesive (Scotchbond 1XT, 3M ESPE) was applied and resin composite build-ups were created. Specimens were immediately tested for μTBS or stored in artificial saliva for 6 and 12 months prior to testing. Additional immediate and 6-month specimens were examined for interfacial nanoleakage analysis under SEM. Matrix metalloproteinase (MMP) inhibition by DMSO was examined with gelatin zymography. Demineralized dentin disks were incubated in 100% DMSO to observe the optical clearing effect. Results The use of 0.5 mM DMSO had no effect on immediate bond strength or nanoleakage. In controls, μTBS decreased significantly after storage, but increased significantly in DMSO-treated group. The control group had significantly lower μTBS than DMSO-group after 6 and 12 months. DMSO also eliminated the increase in nanoleakage seen in controls. 5% and higher DMSO concentrations significantly inhibited the gelatinases. DMSO induced optical clearing effect demonstrating collagen dissociation. Significance DMSO as a solvent may be useful in improving the preservation of long-term dentin-adhesive bond strength. The effect may relate to dentinal enzyme inhibition or improved wetting of collagen by adhesives. The collagen dissociation required much higher DMSO concentrations than the 0.5 mM DMSO used for bonding. © 2013 Academy of Dental Materials.
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Cryopreservation of spermatozoa is a pivotal tool in assisted reproduction, and studies aiming to establish optimal freezing/thawing protocols are essential to enhance sperm survival. The objectives of the present study were to (1) compare the cryoprotective efficiency of three different glycerol concentrations (3%, 5%, and 7%) on the basis of post-thaw sperm quality and (2) investigate whether the incidence of morphologically abnormal sperm in fresh samples is related to cryodamage sensitivity. Semen was collected from six tomcats using an artificial vagina (total 18 ejaculates). Each ejaculate was diluted using Tris-egg yolk-based extender (TEY), evaluated, equally divided into three aliquots, and rediluted using TEY with and without glycerol to achieve final concentrations of 3%, 5%, and 7%. Samples were loaded into 0.25 mL straws, equilibrated for 60 minutes at 5 °C, frozen, and then thawed at 46 °C for 12 seconds. Fresh and frozen-thawed samples were evaluated for sperm motion parameters (computer-assisted sperm analysis), plasma membrane integrity (PMI; propidium iodide and carboxyfluorescein diacetate), and DNA integrity (acridine orange). Plasma and acrosomal membrane integrity were assessed by flow cytometry (propidium iodide and fluorescein isothiocyanate-conjugated pea (Pisum sativum) agglutinin) immediately after thawing. Sperm motion parameters were also evaluated at 30 and 60 minutes of postincubation. For all treatment groups, cryopreservation significantly impaired the PMI and sperm motion parameters, except for straightness and amplitude of lateral head displacement. DNA integrity showed a slight reduction (P < 0.05) when 3% glycerol was used. The percentage of total motility, progressive motility, and rapid spermatozoa were significantly lower immediately after thawing and up to 60 minutes of incubation for the 3% glycerol group when compared with 5% and 7%. No difference (P > 0.05) was found for PMI, acrosome integrity, and DNA integrity among post-thaw groups. However, higher (P < 0.05) incidence of viable cells with reacted acrosome and dead cells with intact acrosome were observed with 7% and 3% glycerol, respectively. Percentage of morphologically abnormal spermatozoa in fresh sample was positively correlated with PMI only in the 3% glycerol group and negatively correlated with sperm motility in the 5% and 7% groups. In conclusion, the final concentration of 5% glycerol offered better cryoprotective effect for ejaculated cat sperm, and the relationship found between prefreezing sperm morphology and post-thaw sperm quality showed to be dependent on final glycerol concentration. © 2013 Elsevier Inc.
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Um estudo foi conduzido para avaliar os efeitos do óleo essencial de copaíba sobre o desempenho e rendimento de abate de frangos de corte. Foram utilizados 450 pintos, distribuídos num delineamento inteiramente casualizado com 5 tratamentos e 6 repetições de 15 aves. Os tratamentos consistiram em Controle (promotor comercial) e quatro níveis de óleo essencial de copaíba sendo estes 0,15 (0,15EO); 0,30 (0,30EO); 0,45 (0,45EO) e 0,60 mL (0,60EO) kg-1 de ração. Aos 21 dias de idade, as aves do tratamento com promotor apresentaram peso corporal superior ao das aves que receberam os tratamentos com 0,30; 0,45 e 0,60 mL de inclusão de óleo essencial (p < 0,05). Aos 40 dias de idade apenas as aves que receberam o tratamento com maior nível de inclusão de óleo essencial apresentaram menor peso corporal em relação ao tratamento com promotor de crescimento. O consumo de ração, a conversão alimentar e a viabilidade das aves, assim como o rendimento de carcaça, cortes comerciais e peso dos órgãos internos não foram afetados pelos tratamentos (p > 0.05). Conclui-se que o óleo essencial de copaíba pode ser usado na ração até o nível de 0,15 mL kg-1 sem afetar o desempenho das aves.
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Paracoccidioidomycosis is diagnosed from the direct observation of the causative agent, but serology can facilitate and decrease the time required for diagnosis. The objective of this study was to determine the influence of serum sample inactivation on the performance of the latex agglutination test (LAT) for detecting antibodies against Paracoccidioides brasiliensis. The sensitivity of LAT from inactivated or non-inactivated samples was 73% and 83%, respectively and the LAT selectivity was 79% and 90%, respectively. The LAT evaluated here was no more specific than the double-immunodiffusion assay. We suggest the investigation of other methods for improving the LAT, such as the use of deglycosylated antigen.