242 research outputs found

    Effects of functional strength training on functional movement and balance in middle-aged adults

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    Functional movement deficiencies cause falls and injuries in adults. Functional strength training (FST) is emerging as a new training method for athletes, middle-aged and older adults, to improve functional movement: The present study was conducted in order to investigate the effects of FST on balance and functional movement in healthy and independent middle-aged adults. The sample for this study consisted of 46 physically active individuals (24 female and 22 male). A total of 46 subjects were divided based on randomly into the functional strength training (FST) group (n = 26) aged: 51.55 ± 3.73 years; height: 168.69 ± 8.8 cm; body mass: 75.88 ± 12.18; and traditional strength training (TST) group (n = 20) age: 52.85 ± 4.01; height: 166.9 ± 9.98; body mass: 76.15 ± 10.45. Each group performed 24 sessions of a training protocol three-time a week. The functional movement was assessed using the functional movement screen (FMS) protocol. Balance performance was determined by using the balance error scoring system (BESS). Bodyweight and body fat ratio were measured using bioelectric impedance. There was a significant statistical difference between FMS total scores after an eight-week FST in the FST group. After the intervention, the functional strength group tended to have significantly better balance control than the traditional strength group (p = 0.01). Statistically, significant differences were observed between pre-test and post-test in the intervention group on BMI, body fat, and body mass (p = 0.01). There were not found significant differences in balance control and FMS score in TST group. As a result of this study, FST positively affected the FMS total score and balance performance in middle-aged adults. Early detections of the deficiencies in functional movement and balance in the middle ages may reduce the risk of insufficiency and fall in adults through targeted functional strength training intervention

    Who Should Bear the Risk? A Theoretical and Behavioral Investigation of After-Sales Service Contracts

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    Since downtime is expensive, it is key to use the right after-sales service contract to achieve high equipment availability. Resource-based contracts (RBCs) are common, but they fail to motivate suppliers to provide reliable products and services as suppliers are paid for their after-sales services. Performance-based contracts (PBCs) have been proposed as a way to solve this issue, as it shifts much of the downtime risk to the supplier by making him responsible for machine uptime, but then customers might reduce care efforts. We are the first to analytically incorporate the care in equipment availability. We propose the full-care contract (FCC) to achieve both high reliability and care, and maximize the chain efficiency. We find that only the FCC can achieve full chain efficiency. After discussing potential behavioral factors in this context, with a focus on risk aversion, we conduct a lab study with decision makers as suppliers. Experimental results confirm that the FCC achieves higher total profits than the PBC and RBC. We further find that subjects are more likely to switch from the RBC to the FCC than to the PBC, despite the higher risk involved in the FCC.Finally, we observe that effort levels set by suppliers are above normative predictions and we discuss potential explanations for this result

    Quantum efficiency enhancement in film by making nanoparticles of polyfluorene

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    Cataloged from PDF version of article.We report on conjugated polymer nanoparticles of polyfluorene that were formed to exhibit higher fluorescence quantum efficiency in film (68%) and reduce undesired emission peak wavelength shifts in film (by 20 nm), compared to the solid-state polymer thin film made directly out of the same polymer solution without forming nanoparticles. Using the facile reprecipitation method, solutions of poly[9,9-dihexyl-9H-fluorene] in THF were added at different volume ratios to obtain different size distributions of nanoparticle dispersions in water. This allowed us to control the sizedependent optical emission of our polyfluorene nanoparticles. Such organic nanoparticles hold great promise for use as efficient emitters in optoelectronic device applications. (C) 2008 Optical Society of America

    Non-radiative resonance energy transfer in bi-polymer nanoparticles of fluorescent conjugated polymers

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    Cataloged from PDF version of article.his work demonstrates the comparative studies of non-radiative resonance energy transfer in bi-polymer nanoparticles based on fluorescent conjugated polymers. For this purpose, poly[(9,9-dihexylfluorene) (PF) as a donor (D) and poly[2-methoxy-5-(2'-ethyl-hexyloxy)-1,4-phenylene vinylene] (MEH-PPV) as an acceptor (A) have been utilized, from which four different bi-polymer nanoparticle systems are designed and synthesized. Both, steady-state fluorescence spectra and time-resolved fluorescence measurements indicate varying energy transfer efficiencies from the host polymer PF to the acceptor polymer MEH-PPV depending on the D-A distances and structural properties of the nanoparticles. The first approach involves the preparation of PF and MEH-PPV nanoparticles separately and mixing them at a certain ratio. In the second approach, first PF and MEH-PPV solutions are mixed prior to nanoparticle formation and then nanoparticles are prepared from the mixture. Third and fourth approaches involve the sequential nanoparticle preparation. In the former, nanoparticles are prepared to have PF as a core and MEH-PPV as a shell. The latter is the reverse of the third in which the core is MEH-PPV and the shell is PF. The highest energy transfer efficiency recorded to be 35% is obtained from the last system, in which a PF layer is sequentially formed on MEH-PPV NPs. © 2010 Optical Society of America

    Dual functionality of conjugated polymer nanoparticles as an anticancer drug carrier and a fluorescent probe for cell imaging

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    Cataloged from PDF version of article.Multifunctional nanoparticles based on a green emitting, hydrophobic conjugated polymer, poly[(9,9-bis{propeny}fluorenyl-2,7-diyl)-co-(1,4- benzo-{2,1,3}-thiodiazole)] (PPFBT), that acts both as a fluorescent reporter and a matrix to accommodate an anti-cancer compound, camptothecin (CPT), were prepared, characterized and their potential as a fluorescent probe for cell imaging and as a drug delivery vehicle were evaluated via in vitro cell assays. The cell viability of human hepatocellular carcinoma cell line (Huh7) was investigated in the absence and presence of CPT with sulforhodamine B (SRB) and real-time cell electronic sensing (RT-CES) cytotoxicity assays

    White emitting polyfluorene functionalized with azide hybridized on near-UV light emitting diode for high color rendering index

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    Cataloged from PDF version of article.We develop and demonstrate high-quality white light generation that relies on the use of a single-type simple conjugated polymer of polyfluorene functionalized with azide groups (PFA) integrated on a near-UV LED platform. The high-quality white emission from the polyfluorene is achieved by using the azide functionalization to facilitate cross-linking intentionally when cast into solid-state form. Hybridized on n-UV InGaN/GaN LED at 378 nm, the PFA emitters collectively generate a very broad down-converting photoluminescence at longer wavelengths across the entirety of the visible spectrum, yielding high color rendering indices up to 91. (c) 2008 Optical Society of America

    Molecular switch based on a cucurbit[6]uril containing bistable [3]rotaxane

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    A bistable CB6-based [3]rotaxane with two recognition sites has been prepared very efficiently in a high yield synthesis through CB6 catalyzed 1,3-dipolar cycloaddition; this rotaxane behaves as a reversible molecular switch and exhibits conformational changes caused by the movement of rings under base, acid and heat stimuli from one location to the other. © The Royal Society of Chemistry

    Facile synthesis of cross-linked patchy fluorescent conjugated polymer nanoparticles by click reactions

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    Here, we report a novel method to synthesize multifunctional nanoparticles that can be used in biological studies, such as in cell imaging and as a carrier for biomolecules/drugs. The nanoparticles were prepared either via Cu-catalyzed or cucurbit[6]uril (CB6)-catalyzed click reactions between azide groups containing hydrophobic blue, green and yellow emitting fluorene-based conjugated polymers and a hydrophilic diaminodialkyne containing cross-linker. Through the click reaction, not only does the cross-linking confer stability, but it also introduces functional groups, such as triazoles and amines, to the nanoparticles. Moreover, CB6 not only acted as a catalyst to facilitate the copper-free click reaction, but it also allowed us to obtain nanoparticles containing rotaxanes in which the triazole units were encapsulated by CB6 units. TEM images of the nanoparticles also showed that they display very interesting morphologies. Incorporation of hydrophilic functional groups to the hydrophobic conjugated polymers resulted in a distinct phase separation, producing Janus-like or patchy particles. © 2011 The Royal Society of Chemistry
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