915 resultados para LED Lamps
Resumo:
Phototherapy improves cellular activation which is an important factor for the treatment of cellulite. The objective of this research was to develop and evaluate the effects of a new (noninvasive and nonpharmacological) clinical procedure to improve body aesthetics: infrared-LED (850 nm) plus treadmill training. Twenty women (25-55 years old) participated in this study. They were separated in two groups: the control group, which carried out only the treadmill training (n = 10), and the LED group, with phototherapy during the treadmill training (n - 10). The training was performed for 45 minutes twice a week over 3 months at intensities between 85% and 90% maximal heart rate (HR(max)). The irradiation parameters were 39 mW/cm(2) and a fluence of 106 J/cm(2). The treatment was evaluated by interpreting body composition parameters, photographs and thermography. This was primarily a treatment for cellulite with a reduction of saddlebag and thigh circumference. At the same time, the treadmill training prevented an increase of body fat, as well as the loss of lean mass. Moreover, thermal images of the temperature modification of the thighs are presented. These positive effects can result in a further improvement of body aesthetics using infrared-LED together with treadmill training.
Resumo:
The indirect adhesive procedures constitute recently a substantial portion of contemporary esthetic restorative treatments. The resin cements have been used to bond tooth substrate and restorative materials. Due to recently introduction of the self-bonding resin luting cement based on a new monomer, filler and initiation technology has become important to study the degree of conversion of these new materials. In the present work the polymerization reaction and the filler content of dual-cured dental resin cements were studied by means of infra-red spectroscopy (FT-IR) and thermogravimetry (TG). Twenty specimens were made in a metallic mold (8 mm diameter x 1 mm thick) from each of 2 cements, PanaviaA (R) F2.0 (Kuraray) and RelyX (TM) Unicem Applicap (3M/ESPE). Each specimen was cured with blue LED with power density of 500 mW/cm(2) for 30 s. Immediately after curing, 24 and 48 h, and 7 days DC was determined. For each time interval 5 specimens were pulverized, pressed with KBr and analyzed with FT-IR. The TG measurements were performed in Netzsch TG 209 under oxygen atmosphere and heating rate of 10A degrees C/min from 25 to 700A degrees C. A two-way ANOVA showed DC (%) mean values statistically significance differences between two cements (p < 0.05). The Tukey`s test showed no significant difference only for the 24 and 48 h after light irradiation for both resin cements (p > 0.05). The Relx-Y (TM) Unicem mean values were significantly higher than PanaviaA (R) F 2.0. The degree of conversion means values increasing with the storage time and the filler content showed similar for both resin cements.
Resumo:
Different light sources and power densities used on the photoactivation process may provide changes in the degree of conversion (DC%) and temperature ( T) of the composite resins. Thus, the purpose of this study was to evaluate the DC (%) and T (degrees C) of the microhybrid composite resin (Filtek (TM) Z-250, 3M/ESPE) photoactivated with one argon laser and one LED (light-emitting diode) with different power densities. For the KBr pellet technique, the composite resin was placed into a metallic mould (2-mm thickness, 4-mm diameter) and photoactivated as follows: a continuous argon laser (CW) and LED LCUs with power density values of 100, 400, 700, and 1000 mW/cm(2) for 20 s. The measurements for DC (%) were made in a FTIR spectrometer Bomen ( model MB 102, Quebec, Canada). Spectroscopy ( FTIR) spectra for both uncured and cured samples were analyzed using an accessory of the reflectance diffusion. The measurements were recorded in absorbance operating under the following conditions: 32 scans, 4 cm(-1) resolution, 300 to 4000-cm(-1) wavelength. The percentage of unreacted carbon double bonds (% C=C) was determined from the ratio of absorbance intensities of aliphatic C=C (peak at 1638 cm(-1)) against an internal standard before and after the curing of the specimen: aromatic C-C (peak at 1608 cm(-1)). For T (degrees C), the samples were created in a metallic mould (2-mm thickness, 4-mm diameter) and photoactivated for 20 s. The thermocouple was attached to the multimeter allowing temperature readings. The DC (%) and T (degrees C) were submitted to ANOVA and Tukey`s test (p < 0.05). The degree of conversion values varied from 35.0 to 50.0% ( 100 to 1000 mW/cm(2)) for an argon laser and from 41.0 to 49% (100 to 1000 mW/cm(2)) for an LED. The temperature change values varied from 1.1 to 13.1 degrees C (100 to 1000 mW/cm(2)) for an argon laser and from 1.9 to 15.0 degrees C (100 to 1000 mW/cm(2)) for an LED. The power densities showed a significant effect on the degree of conversion and changes the temperature for both light-curing units.
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In order to consider the photodynamic therapy (PDT) as a clinical treatment for candidosis, it is necessary to know its cytotoxic effect on normal cells and tissues. Therefore, this study evaluated the toxicity of PDT with PhotogemA (R) associated with red light-emitting diode (LED) on L929 and MDPC-23 cell cultures and healthy rat palatal mucosa. In the in vitro experiment, the cells (30000 cells/cm(2)) were seeded in 24-well plates for 48 h, incubated with PhotogemA (R) (50, 100, or 150 mg/l) and either irradiated or not with a red LED source (630 +/- 3 nm; 75 or 100 J/cm(2); 22 mW/cm(2)). Cell metabolism was evaluated by the MTT assay (ANOVA and Dunnet`s post hoc tests; p < 0.05) and cell morphology was examined by scanning electron microscopy. In the in vivo evaluation, PhotogemA (R) (500 mg/l) was applied to the palatal mucosa of Wistar rats during 30 min and exposed to red LED (630 nm) during 20 min (306 J/cm(2)). The palatal mucosa was photographed for macroscopic analysis at 0, 1, 3, and 7 days posttreatment and subjected to histological analysis after sacrifice of the rats. For both cell lines, there was a statistically significant decrease of the mitochondrial activity (90-97%) for all PhotogemA (R) concentrations associated with red LED regardless of the energy density. However, in the in vivo evaluation, the PDT-treated groups presented intact mucosa with normal characteristics both macroscopically and histologically. From these results, it may be concluded that the association of PhotogemA (R) and red LED caused severe toxic effects on normal cell cultures, characterized by the reduction of mitochondrial activity and morphological alterations, but did not cause damage to the rat palatal mucosa in vivo.
Resumo:
To evaluate the cytotoxicity of PDT (photodynamic therapy) with Photogem (R) associated to blue LED (light-emitting diode) on L929 and MDPC-23 cell cultures, 30000 cells/cm(2) were seeded in 24-well plates for 48 h, incubated with Photogem (R) (10, 25 or 50 mg/l) and irradiated with an LED source (460 +/- 3 nm; 22 mW/cm(2)) at two energy densities (25.5 or 37.5 J/cm(2)). Cell metabolism was evaluated by the MTT (methyltetrazolium) assay (Dunnet`s post hoc tests) and cell morphology by SEM (scanning electron microscopy). Flow cytometry analysed the type of PDT-induced cell death as well and estimated intracellular production of ROS (reactive oxygen species). There was a statistically significant decrease of mitochondrial activity (90% to 97%) for all Photogem (R) concentrations associated to blue LED, regardless of irradiation time. It was also demonstrated that the mitochondrial activity was not recovered after 12 or 24 h, characterizing irreversible cell damage. PDT-treated cells presented an altered morphology with ill-defined limits. In both cell lines, there was a predominance of necrotic cell death and the presence of Photogem (R) or irradiation increased the intracellular levels of ROS. PDT caused severe toxic effects in normal cell culture, characterized by the reduction of the mitochondrial activity, morphological alterations and induction of necrotic cell death.
Resumo:
The assertion of identity and power via computer-mediated communication in the context of distance or web-based learning presents challenges to both teachers and students. When regular, face-to-face classroom interaction is replaced by online chat or group discussion forums, participants must avail themselves of new techniques and tactics for contributing to and furthering interaction, discussion, and learning. During student-only chat sessions, the absence of teacher-led, face-to-face classroom activities requires the students to assume leadership roles and responsibilities normally associated with the teacher. This situation raises the questions of who teaches and who learns; how students discursively negotiate power roles; and whether power emerges as a function of displayed expertise and knowledge or rather the use of authoritative language. This descriptive study represents an examination of a corpus of task-based discussion logs among Vietnamese students of distance learning courses in English linguistics. The data reveal recurring discourse strategies for 1) negotiating the progression of the discussion sessions, 2) asserting and questioning knowledge, and 3) assuming or delegating responsibility. Power is defined ad hoc as the ability to successfully perform these strategies. The data analysis contributes to a better understanding of how working methods and materials can be tailored to students in distance learning courses, and how such students can be empowered by being afforded opportunities and effectively encouraged to assert their knowledge and authority.
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ABSTRACTThe general aim of this thesis was to investigate behavioral change communication at nurse-led chronic obstructive pulmonary disease (COPD) clinics in primary health care, focusing on communication in self-management and smoking cessation for patients with COPD.Designs: Observational, prospective observational and experimental designs were used.Methods: To explore and describe the structure and content of self-management education and smoking cessation communication, consultations between patients (n=30) and nurses (n=7) were videotaped and analyzed with three instruments: Consulting Map (CM), the Motivational Interviewing Treatment Integrity (MITI) scale and the Client Language Assessment in Motivational Interviewing (CLAMI). To examine the effects of structured self-management education, patients with COPD (n=52) were randomized in an intervention and a control group. Patients’ quality of life (QoL), knowledge about COPD and smoking cessation were examined with a questionnaire on knowledge about COPD and smoking habits and with St. George’s Respiratory Questionnaire, addressing QoL. Results: The findings from the videotaped consultations showed that communication about the reasons for consultation mainly concerned medical and physical problems and (to a certain extent) patients´ perceptions. Two consultations ended with shared understanding, but none of the patients received an individual treatment-plan. In the smoking cessation communication the nurses did only to a small extent evoke patients’ reasons for change, fostered collaboration and supported patients’ autonomy. The nurses provided a lot of information (42%), asked closed (21%) rather than open questions (3%), made simpler (14%) rather than complex (2%) reflections and used MI non-adherent (16%) rather than MI-adherent (5%) behavior. Most of the patients’ utterances in the communication were neutral either toward or away from smoking cessation (59%), utterances about reason (desire, ability and need) were 40%, taking steps 1% and commitment to stop smoking 0%. The number of patients who stopped smoking, and patients’ knowledge about the disease and their QoL, was increased by structured self-management education and smoking cessation in collaboration between the patient, nurse and physician and, when necessary, a physiotherapist, a dietician, an occupational therapist and/or a medical social worker.Conclusion The communication at nurse-led COPD clinics rarely involved the patients in shared understanding and responsibility and concerned patients’ fears, worries and problems only to a limited extent. The results also showed that nurses had difficulties in attaining proficiency in behavioral change communication. Structured self-management education showed positive effects on patients’ perceived QoL, on the number of patients who quit smoking and on patients’ knowledge about COPD.
Resumo:
Background: Smokers with chronic obstructive pulmonary disease (COPD) have high nicotine dependence making it difficult to quit smoking. Motivational interviewing (MI) is a method that is used in stimulating motivation and behavioral changes. Objective: To describe smoking cessation communication between patients and registered nurses trained in MI in COPD nurse-led clinics in Swedish primary health care. Methods: A prospective observational study with structured quantitative content analyses of the communication between six nurses with basic education in MI and 13 patients in non-smoking consultations. Results: Only to a small extent did nurses’ evoke patients’ reasons for change, stimulate collaboration, and support patients’ autonomy. Nurses provided information, asked closed questions, and made simple reflections. Patients’ communicationwasmainly neutral and focusing on reasons for and against smoking. It was uncommon for patients to be committed and take steps toward smoking cessation. Conclusion: The nurses did not adhere to the principles of MI in smoking cessation, and the patients focused to a limited extent on how to quit smoking. Practice implications: To make patients more active, the nurses need more education and continuous training in motivational communication.
Resumo:
As colleges and universities make increasing global engagement a top institutional priority, many have struggled to manage rising levels of international activity. Council research finds that the challenge lies not in convincing faculty to expend more effort but instead in reducing the level of effort required by faculty who are already interested in promoting international activities. This study provides detailed case studies and toolkits for administrative core competencies for increased global engagement. Chapter 2 (page 39) details strategies to promote faculty-led study abroad programs, which constitute the fastest growing study abroad experience. Chapter 5 (page 111) outlines recommendations to build strategic international partnerships that engage the entire campus.
Resumo:
O objetivo deste estudo foi avaliar a eficácia de três aparelhos fotopolimerizadores comerciais que utilizam o LED como fonte de luz (Elipar FreeLight - 3M-ESPE, UltraLume-LED2 - Ultradent e Single V - BioArt) na polimerização do compósito Z250 (3M-ESPE), cor A3, através das propriedades: microdureza Knoop, profundidade de polimerização e resistência flexural. Um aparelho fotopolimerizador convencional de lâmpada halógena XL 2500 (3M-ESPE) foi utilizado como controle. Em todos os casos, o tempo de polimerização adotado foi de 20 s. Para o ensaio de microdureza foram confeccionados 10 corpos de prova cilíndricos com 8 mm de diâmetro e 2 mm de altura para cada aparelho fotopolimerizador. A microdureza foi medida 24 h após a confecção dos corpos de prova, que ficaram armazenados em ambiente seco e protegidos da luz. Para o ensaio de profundidade de polimerização foram confeccionados três corpos de prova cilíndricos com 4 mm de diâmetro e 6 mm de altura para cada aparelho fotopolimerizador. O ensaio foi realizado imediatamente após a polimerização do compósito. Para o ensaio de resistência flexural foram confeccionados 5 corpos de prova com 25 mm de comprimento, 2 mm de altura e 2 mm de largura para cada aparelho fotopolimerizador. A resistência flexural foi medida 24 h após a polimerização do compósito e armazenagem dos corpos de prova em água destilada a 37ºC. Os resultados obtidos foram comparados às exigências da especificação 4049:2000 da International Organization for Standardization (ISO) e submetidos à análise estatística para comparação entre os aparelhos. Os valores de microdureza obtidos com os três fotopolimerizadores com LED não mostraram diferença entre si e foram superiores aos obtidos com o aparelho convencional. Para o ensaio de profundidade de polimerização, os valores obtidos com o aparelho Single V foram superiores aos do aparelho convencional, enquanto que os obtidos pelos outros dois aparelhos não apresentaram diferenças significativas entre si e o convencional. Para o ensaio de resistência flexural, não houve diferença entre os valores obtidos pelos três aparelhos com LED e o aparelho convencional. As exigênias da ISO 4049:2000 para os ensaios de profundidade de polimerização e resistência flexural foram atendidas em todos os casos.
Resumo:
O objetivo deste estudo foi avaliar o comportamento de três aparelhos fotoativadores, sendo que dois aparelhos utilizam a tecnologia de diodos emissores de luz (LED) (Radii-SDI; Single V-Bio art) e o ultimo é um aparelho convencional de lâmpada halógena (XL-2500-3M ESPE), sendo que o primeiro apresenta o diodo emissor de luz na extremidade do aparelho; o segundo apresenta ponteira de fibra óptica turbo e o terceiro apresenta ponteira de fibra óptica convencional. O desempenho dos aparelhos foi analisado por meio da análise de microdureza do fundo de um incremento de 2mm do compósito Z250 (3M ESPE), submetido à polimerização em diferentes profundidades: 2mm, 4mm, 6mm e 8mm. Em todos os casos, o tempo de polimerização adotado foi de 20 s. Para obtenção dos corpos de prova, foi utilizada uma matriz de dentina com uma cavidade de 3mm de diâmetro por 2mm de espessura. Para simular as diferentes profundidades de 2mm, 4mm, 6mm e 8mm, foram utilizados espaçadores de dentina em forma de anel com 2mm, 4mm, e 6mm de espessura sobre a matriz. Para o ensaio de microdureza, foram confeccionados cinco corpos de prova para cada combinação entre aparelho fotoativador e as quatro profundidades, totalizando 60 corpos de prova. . O ensaio foi realizado 15min após a polimerização. Os valores de microdureza foram obtidos a partir de cinco endentações em cada corpo de prova. Os resultados obtidos foram submetidos à análise de variância e ao teste Tukey para comparação entre os aparelhos, em cada profundidade (α=0,05). Os valores médios e desvio padrão da microdureza obtidos com os aparelhos Radii(R), Single V (S) e XL-2500(XL), a 2mm, foram respectivamente: 55,16 (±1,66), 58,56 (±1,77), 51,15 (±2,08), mostrando diferença significativa entre eles, sendo que o melhor desempenho foi obtido pelo S seguido pelo R e pelo XL. A 4mm, os valores foram R= 52,23 (±1,66 ); S= 49,04 (±2,04); XL= 47,34 (±2,69), com melhor desempenho do R em relação a XL, porém sem diferença do S. A 6mm, os valores foram R= 46,40 (±1,07); S= 43,64 (±1,56); XL= 42,12 (±1,72). Com melhor desempenho do R, seguidos pelo S e XL que não mostraram diferença entre si. Já a 8mm, os valores foram R= 41,96 (±1,09); S= 38,36(± 0,87); XL= 40,16 (±1,70), com melhor desempenho do R seguido pelo XL e este pelo S, mostrando diferença significativa entre eles. Comparando os aparelhos LED com a lâmpada halógena, pode-se observar que o Radii teve um desempenho superior a ela em todas as profundidades. Já o Single V foi superior na profundidade de 2mm, similar em 4mm e em 6mm e inferior em 8mm, mostrando que os aparelhos LED tiveram um comportamento diferenciado que talvez possa ser atribuído à presença de uma ponteira turbo no Single V. Também com base nos resultados foi possível concluir que houve uma redução significativa, dos valores de microdureza do fundo do material restaurador com o aumento da profundidade da cavidade para todos os aparelhos.
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This paper studies the role of Vertical Specialization-based trade and foreign damand push as elements capable of explaining export-led recoveries in small open industrialized economies. The empirical evidence on export-led recoveries is reviewed. Data supporting the growing importance of vertical specialization for international trade are presented. I compare the performance of two versions of a small open economy model, calibrated to mimic Canadian Business Cycles. The …rst one is based upon Schmitt-Grohe(1998). The second incorporates Vertical- Specialization-based trade. I show that an arti…cial economy featuring Vertical-Specializationbased trade in conjunction with an exogenous AR(2) process for foreign output displays improved impulse responses to a foreign output shock and is able to mimic the contribution of Canadian exports to output growth during economic recoveries.
Resumo:
Latin America has recently experienced three cycles of capital inflows, the first two ending in major financial crises. The first took place between 1973 and the 1982 ‘debt-crisis’. The second took place between the 1989 ‘Brady bonds’ agreement (and the beginning of the economic reforms and financial liberalisation that followed) and the Argentinian 2001/2002 crisis, and ended up with four major crises (as well as the 1997 one in East Asia) — Mexico (1994), Brazil (1999), and two in Argentina (1995 and 2001/2). Finally, the third inflow-cycle began in 2003 as soon as international financial markets felt reassured by the surprisingly neo-liberal orientation of President Lula’s government; this cycle intensified in 2004 with the beginning of a (purely speculative) commodity price-boom, and actually strengthened after a brief interlude following the 2008 global financial crash — and at the time of writing (mid-2011) this cycle is still unfolding, although already showing considerable signs of distress. The main aim of this paper is to analyse the financial crises resulting from this second cycle (both in LA and in East Asia) from the perspective of Keynesian/ Minskyian/ Kindlebergian financial economics. I will attempt to show that no matter how diversely these newly financially liberalised Developing Countries tried to deal with the absorption problem created by the subsequent surges of inflow (and they did follow different routes), they invariably ended up in a major crisis. As a result (and despite the insistence of mainstream analysis), these financial crises took place mostly due to factors that were intrinsic (or inherent) to the workings of over-liquid and under-regulated financial markets — and as such, they were both fully deserved and fairly predictable. Furthermore, these crises point not just to major market failures, but to a systemic market failure: evidence suggests that these crises were the spontaneous outcome of actions by utility-maximising agents, freely operating in friendly (‘light-touch’) regulated, over-liquid financial markets. That is, these crises are clear examples that financial markets can be driven by buyers who take little notice of underlying values — i.e., by investors who have incentives to interpret information in a biased fashion in a systematic way. Thus, ‘fat tails’ also occurred because under these circumstances there is a high likelihood of self-made disastrous events. In other words, markets are not always right — indeed, in the case of financial markets they can be seriously wrong as a whole. Also, as the recent collapse of ‘MF Global’ indicates, the capacity of ‘utility-maximising’ agents operating in (excessively) ‘friendly-regulated’ and over-liquid financial market to learn from previous mistakes seems rather limited.
Resumo:
Latin America has recently experienced three cycles of capital inflows, the first two ending in major financial crises. The first took place between 1973 and the 1982 ‘debt-crisis’. The second took place between the 1989 ‘Brady bonds’ agreement (and the beginning of the economic reforms and financial liberalisation that followed) and the Argentinian 2001/2002 crisis, and ended up with four major crises (as well as the 1997 one in East Asia) — Mexico (1994), Brazil (1999), and two in Argentina (1995 and 2001/2). Finally, the third inflow-cycle began in 2003 as soon as international financial markets felt reassured by the surprisingly neo-liberal orientation of President Lula’s government; this cycle intensified in 2004 with the beginning of a (purely speculative) commodity price-boom, and actually strengthened after a brief interlude following the 2008 global financial crash — and at the time of writing (mid-2011) this cycle is still unfolding, although already showing considerable signs of distress. The main aim of this paper is to analyse the financial crises resulting from this second cycle (both in LA and in East Asia) from the perspective of Keynesian/ Minskyian/ Kindlebergian financial economics. I will attempt to show that no matter how diversely these newly financially liberalised Developing Countries tried to deal with the absorption problem created by the subsequent surges of inflow (and they did follow different routes), they invariably ended up in a major crisis. As a result (and despite the insistence of mainstream analysis), these financial crises took place mostly due to factors that were intrinsic (or inherent) to the workings of over-liquid and under-regulated financial markets — and as such, they were both fully deserved and fairly predictable. Furthermore, these crises point not just to major market failures, but to a systemic market failure: evidence suggests that these crises were the spontaneous outcome of actions by utility-maximising agents, freely operating in friendly (light-touched) regulated, over-liquid financial markets. That is, these crises are clear examples that financial markets can be driven by buyers who take little notice of underlying values — investors have incentives to interpret information in a biased fashion in a systematic way. ‘Fat tails’ also occurred because under these circumstances there is a high likelihood of self-made disastrous events. In other words, markets are not always right — indeed, in the case of financial markets they can be seriously wrong as a whole. Also, as the recent collapse of ‘MF Global’ indicates, the capacity of ‘utility-maximising’ agents operating in unregulated and over-liquid financial market to learn from previous mistakes seems rather limited.