922 resultados para Fiber posts


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We demonstrate the supercontinuum (SC) generation in a suspended-core As2S3 chalcogenide microstructured optical fiber (MOF). The variation of SC is investigated by changing the fiber length, pump peak power and pump wavelength. In the case of long fibers (20 and 40 cm), the SC ranges are discontinuous and stop at the wavelengths shorter than 3500 nm, due to the absorption of fiber. In the case of short fibers (1.3 and 2.4 cm), the SC ranges are continuous and can extend to the wavelengths longer than 4 μm. The SC broadening is observed when the pump peak power increases from 0.24 to 1.32 kW at 2500 nm. The SC range increases with the pump wavelength changing from 2200 to 2600 nm, corresponding to the dispersion of As2S3 MOF from the normal to anomalous region. The SC generation is simulated by the generalized nonlinear Schrödinger equation. The simulation includes the SC difference between 1.3 and 2.4 cm long fiber by 2500 nm pumping, the variation of SC with pump peak power in 2.4 cm long fiber, and the variation of SC with pump wavelength in 1.3 cm long fiber. The simulation agrees well with the experiment.

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A numerical study of As2S3 Raman fiber lasers is carried out to show their potential for the entire coverage of the 3–4-m spectral band. Experimental results are first obtained from such a laser operated under controlled conditions in order to set the fiber parameters (i.e., gain and attenuation coefficients) to be used in the numerical model. An exhaustive numerical analysis is then performed to establish the conditions for optimum lasing performances over the entire 3–4-m spectral band.

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Endodontically treated teeth have necessary use of intracanal posts. Due to the constant need and search for esthetic materials with properties similar to tooth structure remaining fi berglass posts esthetic came good these shortcomings and are increasingly used as a fi rst option for prosthetic rehabilitation. In this case report is described step by step how to perform the cementation of a nonmetallic post and core construction for making a piece prosthetic onlay in a simplifi ed way, by choosing the self-etching cementation technique.

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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An all-fiber approach to terahertz generation using a periodically poled optical fiber is proposed and experimentally demonstrated. In the proposed approach, a continuous-wave THz wave is generated at a periodically poled fiber by beating two optical wavelengths from two laser sources with the wavelength spacing corresponding to the frequency of the THz wave. The key component in the system is the periodically poled fiber, which is made by a twin-hole fiber with the fiber core residing between two holes. The twin-hole fiber is then thermally poled at a temperature of similar to 260 degrees C with a voltage of 3.3 kV applied to the silver electrodes inside the two holes to introduce second-order nonlinearity. The quasi phase matching (QPM) condition is achieved by periodically erasing the thermal poling induced second-order nonlinearity with an ultraviolet laser, which enhances the energy conversion efficiency. The proposed approach is validated by an experiment. The emission of a THz wave centered at 3.8 THz with an output power of 0.5 mu W is observed. The frequency tunability between 2.2 and 3.8 THz is also experimentally demonstrated.

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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The objective of this work was to evaluate the performance of three Japanese group cucumber hybrids, which were cultivated in two cultivation systems. The experiment was designed in a split-plot randomized block design with two cultivation systems (coconut fiber and soil) for commercial Japanese cucumber hybrids ('Tsuyataro', 'Yoshinari' and 'Nankyoku'). After harvesting the cucumbers, we evaluated the number of marketable fruits per plant, the average fruit length, the mean fruit diameter, the bottom fruit diameter, the marketable production of fruits per plant and the marketable yield per hectare. There were significant interactions between the cultivation system and the hybrid, as indicated by the number of marketable fruits. The Nankyoku hybrid had the highest average (14.54 fruits pl(-1)), although it did not differ from the Yoshinari hybrid when grown in coconut fiber. In soil culture, the Yoshinari hybrid had the highest average number of fruits per plant (10.12 fruits pl(-1)) and did not differ from the Tsuyataro hybrid. Cultivation in coconut fiber provided better results for production traits and plant productivity. 'Yoshinari' and 'Nankyoku' were the most productive hybrids. Based on the cucumber cultivation results from a protected environment, the cultivation of hybrid Japanese cucumbers and Yoshinari and Nankyoku hybrids in coconut fiber is recommended.

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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The objectives of this study were to determine (a) the influence of fiber on the sensory characteristics of dry dog foods; (b) differences of coated and uncoated kibbles for aroma and flavor characteristics; (c) palatability of these dry dog foods; and (d) potential associations between palatability and sensory attributes. A total of eight fiber treatments were manufactured: a control (no fiber addition), guava fiber (3%, 6%, and 12%), sugar cane fiber (9%; large and small particle size), and wheat bran fiber (32%; large and small particle size). The results indicated significant effects of fibers on both flavor and texture properties of the samples. Bitter taste and iron and stale aftertaste were examples of flavor attributes that differed with treatment, with highest intensity observed for 12% guava fiber and small particle size sugar cane fiber treatments. Fracturability and initial crispness attributes were lowest for the sugar cane fiber treatments. Flavor of all treatments changed after coating with a palatant, increasing in toasted, brothy, and grainy attributes. The coating also had a masking effect on aroma attributes such as stale, flavor attributes such as iron and bitter taste, and appearance attributes such as porosity. Palatability testing results indicated that the control treatment was preferred over the sugar cane or the wheat bran treatment. The treatment with large sugarcane fiber particles was preferred over the treatment with small particles, while both of the wheat bran treatments were eaten at a similar level. Descriptive sensory analysis data, especially textural attributes, were useful in pinpointing the underlying characteristics and were considered to be reasons that may influence palatability of dog foods manufactured with inclusion of different fibers.

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This study evaluated the effect of ultrasonic vibration on the tensile strength required to remove intraradicular post cemented with different materials. Bovine teeth were selected, and 7 mm of the cervical root canals were prepared to size 5 Largo drill, the posts were cemented with zinc phosphate, Enforce (resin) or Rely X (glass ionomer). The specimens were divided into six groups (n = 10), according to the following procedures: GI-cementation with zinc phosphate associated with traction force; GII-cementation with zinc phosphate associated with ultrasonic activation and traction force; G111-cementation with Enforce associated with traction force; GIV-cementation with Enforce associated with ultrasonic activation and traction force; GV-cementation with Rely X associated with traction force; and GVI-cementation with Rely X associated with ultrasonic activation and traction force. The tensile test was conducted using the electromechanical testing machine, the force was determined by a specialized computer program and ultrasonic activation using the Jet Sonic Four Plus (Gnatus) device in 10P. Concerning to average ranking, GI showed statistically significant difference in comparison with GII and GVI (p < 0.05); there was no statistical difference in GIII and GIV when compared to other groups (p > 0.05). The ultrasound favored the intraradicular post traction regardless of the employed cement in greater or lesser extent. The post removal is a routine practice in the dental office, therefore, new solutions and better alternatives are need to the practitioner. We did not find in the literature many articles referring to this practice. Thus, the results from this study are relevant in the case planning and to promote more treatment options.

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The aim of this study was to verify the effects of running overtraining protocols performed in downhill, uphill, and without inclination on the proteins related to hypertrophy signaling pathway in extensor digitorum longus (EDL) and soleus of C57BL/6 mice. We also performed histological and stereological analyses. Rodents were divided into control (CT; sedentary mice), overtrained by downhill running (OTR/down), overtrained by uphill running (OTR/up), and overtrained by running without inclination (OTR). The incremental load, exhaustive, and grip force tests were used as performance evaluation parameters. 36 h after the grip force test, EDL and soleus were removed and immediately used for immunoblotting analysis or stored at -80°C for histological and stereological analyses. For EDL, OTR/down decreased the protein kinase B (Akt) and tuberous sclerosis protein 2 (TSC2) phosphorylation (p), and increased myostatin, receptor-activated Smads (pSMAD2-3), and insulin receptor substrate-1 (pIRS-1; Ser307/636). OTR/down also presented low and high relative proportions of cytoplasm and connective tissue, respectively. OTR/up increased the mammalian target of rapamycin (pmTOR), 70-kDa ribosomal protein S6 kinase 1 (pS6K1) and pSMAD2-3, and decreased pTSC2. OTR decreased pTSC2 and increased pIRS-1 (Ser636). For soleus, OTR/down increased S6 ribosomal protein (pS6RP) and pSMAD2-3, and decreased pIRS-1 (Ser639). OTR/up decreased pS6K1, pS6RP and pIRS-1 (Ser639), and increased pTSC2 (Ser939), and pSMAD2-3. OTR increased pS6RP, 4E-binding protein-1 (p4E-BP1), pTSC2 (Ser939), and pSMAD2-3, and decreased pIRS-1 (Ser639). In summary, OTR/down inhibited the skeletal muscle hypertrophy with concomitant signs of atrophy in EDL. The effects of OTR/up and OTR depended on the analyzed skeletal muscle type. J. Cell. Physiol. 9999: 1-12, 2015. © 2015 Wiley Periodicals, Inc.