750 resultados para Education -- Effect of technological innovations on
Resumo:
The purpose of this study was to assess the effect of performance feedback on Athletic Trainers’ (ATs) perceived knowledge (PK) and likelihood to pursue continuing education (CE). The investigation was grounded in the theories of “the definition of the situation” (Thomas & Thomas, 1928) and the “illusion of knowing,” (Glenberg, Wilkinson, & Epstein, 1982) suggesting that PK drives behavior. This investigation measured the degree to which knowledge gap predicted CE seeking behavior by providing performance feedback designed to change PK. A pre-test post-test control-group design was used to measure PK and likelihood to pursue CE before and after assessing actual knowledge. ATs (n=103) were randomly sampled and assigned to two groups, with and without performance feedback. Two independent samples t-tests were used to compare groups on the difference scores of the dependent variables. Likelihood to pursue CE was predicted by three variables using multiple linear regression: perceived knowledge, pre-test likelihood to pursue CE, and knowledge gap. There was a 68.4% significant difference (t101= 2.72, p=0.01, ES=0.45) between groups in the change scores for likelihood to pursue CE because of the performance feedback (Experimental group=13.7% increase; Control group= 4.3% increase). The strongest relationship among the dependent variables was between pre-test and post-test measures of likelihood to pursue CE (F2,102=56.80, p<0.01, r=0.73, R2=0.53). The pre- and post-test predictive relationship was enhanced when group was included in the model. In this model [YCEpost=0.76XCEpre-0.34 Xgroup+2.24+E], group accounted for a significant amount of unique variance in predicting CE while the pre-test likelihood to pursue CE variable was held constant (F3,102=40.28, p<0.01,: r=0.74, R2=0.55). Pre-test knowledge gap, regardless of group allocation, was a linear predictor of the likelihood to pursue CE (F1,102=10.90, p=.01, r=.31, R2=.10). In this investigation, performance feedback significantly increased participants’ likelihood to pursue CE. Pre-test knowledge gap was a significant predictor of likelihood to pursue CE, regardless if performance feedback was provided. ATs may have self-assessed and engaged in internal feedback as a result of their test-taking experience. These findings indicate that feedback, both internal and external, may be necessary to trigger CE seeking behavior.
Resumo:
Thermoplastic starch (TPS) was modified with ascorbic acid and citric acid by melt processing of native starch with glycerol as plasticizer in an intensive batch mixer at 160 degrees C. It was found that the molar mass decreases with acid content and processing time causing the reduction in melting temperature (T(m)). As observed by the results of X-ray diffraction and DSC measurements, crystallinity was not changed by the reaction with organic acids. T(m) depression with falling molar mass was interpreted on the basis of the effect of concentration of end-chain units, which act as diluents. FTIR did not show any appreciable change in starch chemical compositions, leading to the conclusion that the main changes observed were produced by the variation in molar mass of the material. We demonstrated that it is possible to decrease melt viscosity without the need for more plasticizer thus avoiding side-effects such as an increase in water affinity or relevant changes in the dynamic mechanical properties. (C) 2010 Elsevier B.V. All rights reserved.
Resumo:
The relation between the properties of polyampholytes in aqueous solution and their adsorption behaviors on silica and cellulose surfaces was investigated. Four polyampholytes carrying different charge densities but with the same nominal ratio of positive to negative segments and two structurally similar polyelectrolytes (a polyacid and a polybase) were investigated by using quartz crystal microgravimetry using silica-coated and cellulose-coated quartz resonators. Time-resolved mass and rigidity (or viscoelasticity) of the adsorbed layer was determined from the shifts in frequency (Delta f) and energy dissipation (Delta D) of the respective resonator. Therefore, elucidation of the dynamics and extent of adsorption, as well as the conformational changes of the adsorbed macromolecules, were possible. The charge properties of the solid Surface played a crucial role in the adsorption of the studied polyampholytes, which was explained by the capability of the surface to polarize the polyampholyte at the interface. Under the same experimental conditions, the polyampholytes had a higher nominal charge density phase-separated near the interface, producing a soft, dissipative, and loosely bound layer. In the case of cellulose substrates, where adsorption was limited, electrostatic and polarization effects were concluded to be less significant.
Resumo:
In a series of tritrophic-level interaction experiments, the effect of selected host plants of the spider mites, Tetranychus evansi and Tetranychus urticae, on Neozygites floridana was studied by evaluating the attachment of capilliconidia, presence of hyphal bodies in the infected mites, mortality from fungal infection, mummification and sporulation from fungus-killed mite cadavers. Host plants tested for T. evansi were tomato, cherry tomato, eggplant, nightshade, and pepper while host plants tested for T. urticae were strawberry, jack bean, cotton and Gerbera. Oviposition rate of the mites on each plant was determined to infer host plant suitability while host-switching determined antibiosis effect on fungal activity. T. evansi had a high oviposition on eggplant, tomato and nightshade but not on cherry tomato and pepper. T. urticae on jack bean resulted in a higher oviposition than on strawberry, cotton and Gerbera. Attachment of capilliconidia to the T. evansi body, presence of hyphal bodies in infected T. evansi and mortality from fungal infection were significantly higher on pepper, nightshade and tomato. The highest level of T. evansi mummification was observed on tomato. T. evansi cadavers from tomato and eggplant produced more primary conidia than those from cherry tomato, nightshade and pepper. Switching N. floridana infected T. evansi from one of five Solanaceous host plants to tomato had no prominent effect on N. floridana performance. For T. urticae, strawberry and jack bean provided the best N. floridana performance when considering all measured parameters. Strawberry also had the highest primary conidia production. This study shows that performance of N. floridana can vary with host plants and may be an important factor for the development of N. floridana epizootics. (C) 2011 Elsevier Inc. All rights reserved.
Resumo:
Green fluorescent protein (GFP) shows remarkable structural stability and high fluorescence; its stability can be directly related to its fluorescence output, among other characteristics. GFP is stable under increasing temperatures, and its thermal denaturation is highly reproducible. Some polymers, such as polyethylene glycol, are often used as modifiers of characteristics of biological macromolecules, to improve the biochemical activity and stability of proteins or drug bioavailability. The aim of this study was to evaluate the thermal stability of GFP in the presence of different PEG molar weights at several concentrations and exposed to constant temperatures, in a range of 70-95 degrees C. Thermal stability was expressed in decimal reduction time. It was observed that the D-values obtained were almost constant for temperatures of 85, 90, and 95 degrees C, despite the PEG concentration or molar weight studied. Even though PEG can stabilize proteins, only at 75 degrees C, PEG 600 and 4,000 g/mol stabilized GFP. (C) 2009 American Institute of Chemical Engineers Biotechnol. Prog., 26: 252-256, 2010
Resumo:
This article presents an evaluation of the effects of the spouted bed design and operating conditions on system fluiddynamics and process performance during enteric coating of hard gelatine capsules. The design parameters studied were the column diameter (150 mm and 200 mm), the included angle of the conical base, gamma (60 degrees or 40 degrees) and the presence or absence of a Venturi inserted before the inlet air orifice. The process variables studied were the ratio between the feed flow rate of the coating suspension to the spouting gas flow rate (W(s)/W(g)), the mass of capsules loaded to the equipment (M(0)), and the ratio between the Spouting gas flow rate to the gas flow rate at minimum spouting condition (Q/Q(ms)). The response variables were the rate of increase of the capsules mass (K(1)), and the adhesion efficiency (eta). The linear regression equation for the dependent variable K, in terms of the independent variables adequately described the process with an r(2) value of 0.872. Analysis of variance (ANOVA) revealed that increasing of W(s)/W(g), Q/Q(ms) and gamma significantly increased the adhesion efficiency. Adhesion efficiencies higher than 90% were achieved by selecting precise coating conditions, indicating the feasibility of the process for coating of hard gelatine capsules. (C) 2008 Elsevier B.V. All rights reserved.
Resumo:
PURPOSE. To evaluate the effect of disease severity on the diagnostic accuracy of the Cirrus Optical Coherence Tomograph (Cirrus HD-OCT; Carl Zeiss Meditec, Inc., Dublin, CA) for glaucoma detection. METHODS. One hundred thirty-five glaucomatous eyes of 99 patients and 79 normal eyes of 47 control subjects were recruited from the longitudinal Diagnostic Innovations in Glaucoma Study (DIGS). The severity of the disease was graded based on the visual field index (VFI) from standard automated perimetry. Imaging of the retinal nerve fiber layer (RNFL) was obtained using the optic disc cube protocol available on the Cirrus HD-OCT. Pooled receiver operating characteristic (ROC) curves were initially obtained for each parameter of the Cirrus HD-OCT. The effect of disease severity on diagnostic performance was evaluated by fitting an ROC regression model, with VFI used as a covariate, and calculating the area under the ROC curve (AUCs) for different levels of disease severity. RESULTS. The largest pooled AUCs were for average thickness (0.892), inferior quadrant thickness (0.881), and superior quadrant thickness (0.874). Disease severity had a significant influence on the detection of glaucoma. For the average RNFL thickness parameter, AUCs were 0.962, 0.932, 0.886, and 0.822 for VFIs of 70%, 80%, 90%, and 100%, respectively. CONCLUSIONS. Disease severity had a significant effect on the diagnostic performance of the Cirrus HD-OCT and thus should be considered when interpreting results from this device and when considering the potential applications of this instrument for diagnosing glaucoma in the various clinical settings. (Invest Ophthalmol Vis Sci. 2010;51:4104-4109) DOI:10.1167/iovs.094716
Resumo:
The aim of this study was to evaluate the effect of laser irradiation (LI) on enzymatic activities of amylase, catalase and peroxidase in the parotid glands (PG) of diabetic and non-diabetic rats. Ninety-six female rats were divided into eight groups: D0; D5; D10; D20 and C0; C5; C10; C20, respectively. Diabetes was induced by administration of streptozotocin and confirmed later by the glycemia results. Twenty-nine (29) days after the induction, the PGs of groups D5 and C5; D10 and C10; D20 and C20, were irradiated with 5 J/cm(2), 10 J/cm(2) and 20 J/cm(2) of laser diode (660 nm/100 mW) respectively. On the following day, the rats were euthanized and the enzymatic activity in the PGs was measured. Diabetic rats that had not been irradiated (group D0) showed higher catalase activity (P < 0.05) than those in group C0 (0.14 +/- 0.02 U/mg protein and 0.10 +/- 0.03 U/mg protein, respectively). However, laser irradiation of 5 J/cm(2) and 20 J/cm(2) decreased the catalase activity of the diabetic groups (D5 and D20) to non-diabetic values (P > 0.05). Based on the results of this study, LI decreased catalase activity in the PGs of diabetic rats.
Resumo:
Provision of an inert gas atmosphere with high-purity argon gas is recommended for preventing titanium castings from contamination although the effects of the level of argon purity on the mechanical properties and the clinical performance of Ti castings have not yet been investigated. The purpose of this study was to evaluate the effect of argon purity on the mechanical properties and microstructure of commercially pure (cp) Ti and Ti-6Al-4V alloys. The castings were made using either high-purity and/or industrial argon gas. The ultimate tensile strength (UTS), proportional limit (PL), elongation (EL) and microhardness (VHN) at different depths were evaluated. The microstructure of the alloys was also revealed and the fracture mode was analyzed by scanning electron microscopy. The data from the mechanical tests and hardness were subjected to a two-and three-way ANOVA and Tukey`s test (alpha = 0.05). The mean values of mechanical properties were not affected by the argon gas purity. Higher UTS, PL and VHN, and lower EL were observed for Ti-6Al-4V. The microhardness was not influenced by the argon gas purity. The industrial argon gas can be used to cast cp Ti and Ti-6Al-4V.
Resumo:
Transformation of small avascular masses of tumor cells into rapidly progressive cancers is triggered by the angiogenic switch, a process that involves vascular endothelial growth factor (VEGF) signaling. We have shown that VEGF enhances the survival and angiogenic potential of endothelial cells by activating the Bcl-2-CXCL8 signaling axis. The purpose of this study was to evaluate the effect of a small-molecule inhibitor of VEGF receptors (PTK/ZK) on the initial stages of head and neck tumor angiogenesis. In vitro, PTK/ZK blocked head and neck tumor cell (OSCC3 or UM-SCC-17B)-induced Bcl-2 and CXCL8 expression in endothelial cells. Oral administration of PTK/ZK decreased xenograft head and neck tumor microvessel density, and inhibited Bcl-2 and CXCL8 expression in tumor-associated endothelial cells. Analysis of these data demonstrates that PTK/ZK blocks downstream targets of VEGF signaling in endothelial cells, and suggests that PTK/ZK may inhibit the angiogenic switch in head and neck tumors. Abbreviations: HDMEC, human dermal microvascular endothelial cells; VEGF, vascular endothelial growth factor; CXCL8, CXC ligand-8; PTK/ZK, PTK787/ZK222584.
The Effect of TAK-778 on Gene Expression of Osteoblastic Cells Is Mediated Through Estrogen Receptor
Resumo:
This study evaluated the effect of TAK-778 [(2R, 4S)-(-)-N-(4-diethoxyphosphorylmethylphenyl)-1,2,4,5-tetrahydro-4-methyl-7,8-methylenedioxy-5-oxo-3-benzothiepin-2-carboxamide)] on in vitro osteogenic events and on gene expression of osteoblastic cells derived from human alveolar bone and the participation of estrogen receptors (ERs) on such effect. Osteoblastic cells were subcultured, with or without TAK-778 (10(-5) M), to evaluate cell growth and viability, total protein content, and alkaline phosphatase (ALP) activity at 7, 14, and 21 days; bone-like formation at 21 days; and gene expression, using cDNA microarray, at 7 days. Also, osteoblastic cells were exposed to TAK-778 (10-5 M) combined to ICI182,780, a nonspecific ER antagonist (10(-6) M), and gene expression was evaluated by real-time polymerase chain reaction (PCR) at 7 days. TAK-778 induced a reduction in culture growth and an increase in cell synthesis, ALP activity, and bone-like formation. The cDNA microarray showed genes associated with cell adhesion and differentiation, skeletal development, ossification, and transforming growth factor-P receptor signaling pathway, with a tendency to be higher expressed in cells exposed to TAK-778. The gene expression of ALP, osteocalcin, Msh homeobox 2, receptor activator of NF-kappa B ligand, and intercellular adhesion molecule 1 was increased by TAK-778 as demonstrated by real-time PCR, and this effect was antagonized by ICI182,780. The present results demonstrated that TAK-778 acts at a transcriptional level to enhance the in vitro osteogenic process and that its effect on gene expression of osteoblastic cells is mediated, at least partially, through ERs. Based on these findings, TAK-778 could be considered in the treatment of bone metabolic disorders. Exp Biol Med 234:190-199, 2009
Resumo:
Purpose: This study evaluated the effect of different microwave polymerization cycles on the color changes of a microwave-processed denture base resin after accelerated aging and immersion in beverages. Materials and Methods: Specimens of light pink acrylic resin were divided into three groups according to polymerization cycle: (A) 500 W for 3 minutes, (B) 90 W for 13 minutes + 500 W for 90 seconds, and (C) 320 W for 3 minutes + 0 W for 4 minutes + 720 W for 3 minutes. Control groups were a heat-processed acrylic resin (T) and a chemically activated denture repair resin (Q). Eight specimens per group were aged in an artificial aging chamber and evaluated at 20, 192, and 384 hours. Another series of 40 specimens per group were immersed in water, coffee, tea, cola, or red wine and evaluated at 1, 12, and 36 days. Color was measured by a spectrophotometer before and after aging or immersion. Color changes (Delta E) were analyzed by ANOVA/Bonferroni t-test (alpha = 0.05). Results: Mean Delta E (+/- SD) after 384 hours of accelerated aging were (A) 2.51 +/- 0.50; (B) 3.16 +/- 1.09; (C) 2.89 +/- 1.06; (T) 2.64 +/- 0.34; and (Q) 9.03 +/- 0.40. Group Q had a significantly higher Delta E than the other groups. Color changes of immersed specimens were significantly influenced by solutions and time, but the five groups showed similar values. Mean Delta E at 36 days were (water) 1.4 +/- 0.8; (coffee) 1.3 +/- 0.6; (tea) 1.7 +/- 0.5; (cola) 1.4 +/- 0.7; and (red wine) 10.2 +/- 2.7. Results were similar among the five test groups. Conclusions: Color changes of the microwave-polymerized denture base resin tested were not affected by different polymerization cycles after accelerated aging or immersion in beverages. These changes were similar to the conventional heat-polymerized acrylic resin test, but lower than the repair resin after accelerated aging.
Resumo:
Objective: To examine the association between gain in motor and cognitive functional status with patient satisfaction 3-6 mo after rehabilitation discharge. Design: Patient satisfaction and changes in functional status were examined in 18,375 patients with stroke who received inpatient medical rehabilitation. Information was obtained from 144 hospitals and rehabilitation facilities contributing records to the Uniform Data System for Medical Rehabilitation and the National Follow-up Services. Results: Data analysis revealed significant (P < 0.05) differences in satisfaction responses based on whether information was collected from patient self-report or from a family member proxy, and the two subsets were analyzed separately. Logistic regression revealed the following significant predictors of satisfaction for data collected from stroke patients: cognitive and motor gain, rehospitalization, who the patient was living with at follow-up, age, and follow-up therapy. In the patient-reported data subset, compared with patients who showed improved cognitive or motor functional status, those with no change, respectively, had a 31% and 33% reduced risk of dissatisfaction. In addition, rehospitalized patients had a higher risk of dissatisfaction. For the proxy reported data subset, significant influences on satisfaction were health maintenance, rehospitalization, stroke type, ethnicity, cognitive FIM(TM) gain, length of stay, and follow-up therapy. Conclusions: Ratings of satisfaction with rehabilitation services were affected by change in functional status and whether the information was collected from patient rating or proxy response.
Resumo:
The discovery of X-rays was undoubtedly one of the greatest stimulus for improving the efficiency in the provision of healthcare services. The ability to view, non-invasively, inside the human body has greatly facilitated the work of professionals in diagnosis of diseases. The exclusive focus on image quality (IQ), without understanding how they are obtained, affect negatively the efficiency in diagnostic radiology. The equilibrium between the benefits and the risks are often forgotten. It is necessary to adopt optimization strategies to maximize the benefits (image quality) and minimize risk (dose to the patient) in radiological facilities. In radiology, the implementation of optimization strategies involves an understanding of images acquisition process. When a radiographer adopts a certain value of a parameter (tube potential [kVp], tube current-exposure time product [mAs] or additional filtration), it is essential to know its meaning and impact of their variation in dose and image quality. Without this, any optimization strategy will be a failure. Worldwide, data show that use of x-rays has been increasingly frequent. In Cabo Verde, we note an effort by healthcare institutions (e.g. Ministry of Health) in equipping radiological facilities and the recent installation of a telemedicine system requires purchase of new radiological equipment. In addition, the transition from screen-films to digital systems is characterized by a raise in patient exposure. Given that this transition is slower in less developed countries, as is the case of Cabo Verde, the need to adopt optimization strategies becomes increasingly necessary. This study was conducted as an attempt to answer that need. Although this work is about objective evaluation of image quality, and in medical practice the evaluation is usually subjective (visual evaluation of images by radiographer / radiologist), studies reported a correlation between these two types of evaluation (objective and subjective) [5-7] which accredits for conducting such studies. The purpose of this study is to evaluate the effect of exposure parameters (kVp and mAs) when using additional Cooper (Cu) filtration in dose and image quality in a Computed Radiography system.
Resumo:
Diffusion of Innovation is a topic of interest for researchers and practitioners. Although substantial research is conducted on user categories, researchers often focus on the first half of the curve, ignoring the late adopters. We conduct two studies to measure the attributes of late adopters. In our first study of mobile phone users, we develop the Late-Adopter Scale. We then test it on a sample of laptop users. This scale is multi-dimensional, presents nomological and discriminant validity and has three dimensions: 1) rate of adoption, 2) resistance to innovation, and 3) skepticism. Findings reveal that all three Late Adopter Scale dimensions are significantly associated with low price preference. Moreover, in both samples skepticism is associated with high preference for simple products, lower leading edge status, and lower product involvement. Discussion focuses on implications of this new scale to theory and practice of new product development and diffusion of innovation.