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2.
Artigo em Inglês | MEDLINE | ID: mdl-35457676

RESUMO

This paper introduces an interactive music tempo control with closed-loop heart rate feedback to yield a sportsperson with better physio-psychological states. A total of 23 participants (13 men, 10 women; 16−32 years, mean = 20.04 years) who are professionals or school team members further guide a sportsperson to amend their physical tempo to harmonize their psychological and physical states. The self-tuning mechanism between the surroundings and the human can be amplified using interactive music tempo control. The experiments showed that listening to interactive music had a significant effect on the heart rate and rating of perceived exertion (RPE) of the basketball player compared to those listening to asynchronous music or no music during exercise (p < 0.01). Synchronized interactive music allows athletes to increase their heart rate and decrease RPE during exercise and does not require a multitude of preplanned playlists. All self-selected songs can be converted into sports-oriented music using algorithms. The algorithms of synchronous and asynchronous modes in this study can be adjusted and applied to other sports fields or recovery after exercise. In the future, other musical parameters should be adjusted in real-time based on physiological signals, such as tonality, beats, chords, and orchestration.


Assuntos
Basquetebol , Música , Exercício Físico/fisiologia , Retroalimentação , Feminino , Frequência Cardíaca/fisiologia , Humanos , Masculino
3.
J Healthc Eng ; 2017: 3789386, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-29065590

RESUMO

Numerous EEG-based brain-computer interface (BCI) systems that are being developed focus on novel feature extraction algorithms, classification methods and combining existing approaches to create hybrid BCIs. Several recent studies demonstrated various advantages of hybrid BCI systems in terms of an improved accuracy or number of commands available for the user. But still, BCI systems are far from realization for daily use. Having high performance with less number of channels is one of the challenging issues that persists, especially with hybrid BCI systems, where multiple channels are necessary to record information from two or more EEG signal components. Therefore, this work proposes a single-channel (C3 or C4) hybrid BCI system that combines motor imagery (MI) and steady-state visually evoked potential (SSVEP) approaches. This study demonstrates that besides MI features, SSVEP features can also be captured from C3 or C4 channel. The results show that due to rich feature information (MI and SSVEP) at these channels, the proposed hybrid BCI system outperforms both MI- and SSVEP-based systems having an average classification accuracy of 85.6 ± 7.7% in a two-class task.


Assuntos
Interfaces Cérebro-Computador , Eletroencefalografia , Potenciais Evocados Visuais , Feminino , Voluntários Saudáveis , Humanos , Masculino , Análise e Desempenho de Tarefas , Interface Usuário-Computador , Adulto Jovem
4.
Nano Lett ; 15(4): 2278-84, 2015 Apr 08.
Artigo em Inglês | MEDLINE | ID: mdl-25807012

RESUMO

The thickness-dependent band structure of MoS2 implies that discontinuities in energy bands exist at the interface of monolayer (1L) and multilayer (ML) thin films. The characteristics of such heterojunctions are analyzed here using current versus voltage measurements, scanning photocurrent microscopy, and finite element simulations of charge carrier transport. Rectifying I-V curves are consistently observed between contacts on opposite sides of 1L/ML junctions, and a strong bias-dependent photocurrent is observed at the junction. Finite element device simulations with varying carrier concentrations and electron affinities show that a type II band alignment at single layer/multilayer junctions reproduces both the rectifying electrical characteristics and the photocurrent response under bias. However, the zero-bias junction photocurrent and its energy dependence are not explained by conventional photovoltaic and photothermoelectric mechanisms, indicating the contributions of hot carriers.

5.
Life Sci ; 100(2): 110-117, 2014 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-24530290

RESUMO

AIMS: Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) has been considered to be one of the most promising candidates in research on treatments for cancer, including renal cell carcinoma (RCC). However, many cells are resistant to TRAIL-induced apoptosis which limits the potential application of TRAIL in cancer therapy. Luteolin, a naturally occurring flavonoid, has been identified as a potential therapeutic and preventive agent for cancer because of its potent cancer cell-killing activity. In this study, we investigated whether luteolin treatment could modulate TRAIL-induced apoptosis in RCC. MAIN METHODS: The effect of luteolin on TRAIL sensitivity was assessed in human RCC 786-O, ACHN, and A498 cells. The underlying regulatory cascades were approached by biochemical and pharmacological strategies. KEY FINDINGS: We found that nontoxic concentration of luteolin alone had no effect on the level of apoptosis, but a combination treatment of TRAIL and luteolin caused significant extrinsic and intrinsic apoptosis. The sensitization was accompanied by Bid cleavage, Mcl-1 and FLIP down-regulation, DR4/DR5 protein expression and cell surface presentation, and Akt and signal transducer and activator of transcription-3 (STAT3) inactivation. Among these phenomena, changes in FLIP, Akt, and, STAT3 are more prone to the effects of luteolin treatment. Studies have further demonstrated that inactivation of Akt or STAT3 alone was sufficient to down-regulate FLIP expression and sensitized 786-O cells to TRAIL-induced apoptosis. SIGNIFICANCE: Data from this study thus provide in vitro evidence supporting the notion that luteolin is a potential sensitizer of TRAIL in anticancer therapy against human RCC involving Akt and STAT3 inactivation.


Assuntos
Apoptose/efeitos dos fármacos , Carcinoma de Células Renais/patologia , Resistencia a Medicamentos Antineoplásicos , Neoplasias Renais/patologia , Luteolina/farmacologia , Ligante Indutor de Apoptose Relacionado a TNF/metabolismo , Proteínas Reguladoras de Apoptose/genética , Proteínas Reguladoras de Apoptose/metabolismo , Western Blotting , Carcinoma de Células Renais/tratamento farmacológico , Carcinoma de Células Renais/metabolismo , Proliferação de Células/efeitos dos fármacos , Citometria de Fluxo , Humanos , Neoplasias Renais/tratamento farmacológico , Neoplasias Renais/metabolismo , Proteínas Proto-Oncogênicas c-akt/genética , Proteínas Proto-Oncogênicas c-akt/metabolismo , RNA Mensageiro/genética , Reação em Cadeia da Polimerase em Tempo Real , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Fator de Transcrição STAT3/genética , Fator de Transcrição STAT3/metabolismo , Ligante Indutor de Apoptose Relacionado a TNF/genética , Células Tumorais Cultivadas
6.
Proc Natl Acad Sci U S A ; 110(45): 18076-80, 2013 Nov 05.
Artigo em Inglês | MEDLINE | ID: mdl-24145425

RESUMO

The p-n junction diode and field-effect transistor are the two most ubiquitous building blocks of modern electronics and optoelectronics. In recent years, the emergence of reduced dimensionality materials has suggested that these components can be scaled down to atomic thicknesses. Although high-performance field-effect devices have been achieved from monolayered materials and their heterostructures, a p-n heterojunction diode derived from ultrathin materials is notably absent and constrains the fabrication of complex electronic and optoelectronic circuits. Here we demonstrate a gate-tunable p-n heterojunction diode using semiconducting single-walled carbon nanotubes (SWCNTs) and single-layer molybdenum disulfide as p-type and n-type semiconductors, respectively. The vertical stacking of these two direct band gap semiconductors forms a heterojunction with electrical characteristics that can be tuned with an applied gate bias to achieve a wide range of charge transport behavior ranging from insulating to rectifying with forward-to-reverse bias current ratios exceeding 10(4). This heterojunction diode also responds strongly to optical irradiation with an external quantum efficiency of 25% and fast photoresponse <15 µs. Because SWCNTs have a diverse range of electrical properties as a function of chirality and an increasing number of atomically thin 2D nanomaterials are being isolated, the gate-tunable p-n heterojunction concept presented here should be widely generalizable to realize diverse ultrathin, high-performance electronics and optoelectronics.


Assuntos
Dissulfetos/química , Eletrônica/métodos , Molibdênio/química , Nanotubos de Carbono/química , Semicondutores
7.
Artigo em Inglês | MEDLINE | ID: mdl-23476679

RESUMO

There is a growing interest in the health-promoting effects of natural substances obtained from plants. Although luteolin has been identified as a potential therapeutic and preventive agent for cancer because of its potent cancer cell-killing activity, the molecular mechanisms have not been well elucidated. This study provides evidence of an alternative target for luteolin and sheds light on the mechanism of its physiological benefits. Treatment of 786-O renal cell carcinoma (RCC) cells (as well as A498 and ACHN) with luteolin caused cell apoptosis and death. This cytotoxicity was caused by the downregulation of Akt and resultant upregulation of apoptosis signal-regulating kinase-1 (Ask1), p38, and c-Jun N-terminal kinase (JNK) activities, probably via protein phosphatase 2A (PP2A) activation. In addition to being a concurrent substrate of caspases and event of cell death, heat shock protein-90 (HSP90) cleavage might also play a role in driving further cellular alterations and cell death, at least in part, involving an Akt-related mechanism. Due to the high expression of HSP90 and Akt-related molecules in RCC and other cancer cells, our findings suggest that PP2A activation might work in concert with HSP90 cleavage to inactivate Akt and lead to a vicious caspase-dependent apoptotic cycle in luteolin-treated 786-O cells.

8.
Waste Manag ; 32(3): 595-602, 2012 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-22195602

RESUMO

This paper attempts to compare the relative efficiency across MSW incineration facilities under the three operating modes including government-owned government-operated (GOO), government-owned private-operated (GOPO), and private-owned private-operated (POPO) by using the Data Envelopment Analysis (DEA), and to examine the factor in affecting the efficiency variation. The results show that technical efficiency scores are 0.7538, 0.9046 and 0.9917 for GOO, GOPO and POPO, respectively. An ANOVA is conducted and the analysis result confirms that the operating mode has significant impact on technical efficiencies. A further examination on the operating contracts signed between governments and operating firms of GOPO facilities finds that both the price protection and quantity protection also play vital roles in affecting efficiencies.


Assuntos
Incineração , Privatização , Estatística como Assunto
9.
Nano Lett ; 11(4): 1782-5, 2011 Apr 13.
Artigo em Inglês | MEDLINE | ID: mdl-21413780

RESUMO

We demonstrate a fully tunable diode structure utilizing a fully suspended single-walled carbon nanotube. The diode's turn-on voltage under forward bias can be continuously tuned up to 4.3 V by controlling gate voltages, which is ∼6 times the nanotube band gap energy. Furthermore, the same device design can be configured into a backward diode by tuning the band-to-band tunneling current with gate voltages. A nanotube backward diode is demonstrated for the first time with nonlinearity exceeding the ideal diode. These results suggest that a tunable nanotube diode can be a unique building block for developing next generation programmable nanoelectronic logic and integrated circuits.


Assuntos
Nanotubos de Carbono/química , Nanotubos de Carbono/ultraestrutura , Semicondutores , Desenho de Equipamento , Análise de Falha de Equipamento , Teste de Materiais , Tamanho da Partícula
10.
Nano Lett ; 11(4): 1448-51, 2011 Apr 13.
Artigo em Inglês | MEDLINE | ID: mdl-21428322

RESUMO

We report the capacitive spring softening effect observed in single-walled carbon nanotube (SWNT) nanoelectromechanical (NEM) resonators. The nanotube resonators adopt a dual-gate configuration with both bottom-gate and end-gate capable of tuning the resonance frequency through capacitive coupling. Interestingly, downward resonance frequency shifting is observed with increasing end-gate voltage, which can be attributed to the capacitive softening of the spring constant. Furthermore, in-plane vibrational modes exhibit a much stronger spring softening effect than out-of-plan modes. Our dual-gate design should enable the differentiation between these two types of vibrational modes and open up the new possibility for nonlinear operation of nanotube resonators.


Assuntos
Sistemas Microeletromecânicos/instrumentação , Nanotecnologia/instrumentação , Nanotubos de Carbono/química , Nanotubos de Carbono/ultraestrutura , Transdutores , Capacitância Elétrica , Desenho de Equipamento , Análise de Falha de Equipamento
11.
Nano Lett ; 10(3): 1032-6, 2010 Mar 10.
Artigo em Inglês | MEDLINE | ID: mdl-20108926

RESUMO

We report a one-step direct transfer technique for the fabrication of functional nanoelectronic devices using pristine single-walled carbon nanotubes (SWNTs). Suspended SWNTs grown by the chemical vapor deposition (CVD) method are aligned and directly transferred onto prepatterned device electrodes at ambient temperature. Using this technique, we successfully fabricated SWNT electromechanical resonators with gate-tunable resonance frequencies. A fully suspended SWNT p-n diode has also been demonstrated with the diode ideality factor equal to 1. Our method eliminates the organic residues on SWNTs resulting from conventional lithography and solution processing. The results open up opportunities for the fundamental study of electron transport physics in ultraclean SWNTs and for room temperature fabrication of novel functional devices based on pristine SWNTs.


Assuntos
Cristalização/métodos , Nanotecnologia/instrumentação , Nanotubos de Carbono/química , Nanotubos de Carbono/ultraestrutura , Semicondutores , Desenho de Equipamento , Análise de Falha de Equipamento , Substâncias Macromoleculares/química , Teste de Materiais , Conformação Molecular , Tamanho da Partícula , Propriedades de Superfície
12.
Math Biosci ; 207(1): 138-60, 2007 May.
Artigo em Inglês | MEDLINE | ID: mdl-17112550

RESUMO

Free access to a common pool of resource in a country may lead to over-exploitation and sacrifice future opportunities of harvesting. As such, the protection of a common fishery resource is worth investigating. In this paper we develop a two-period model and a multi-period model to analyze the optimal inter-temporal utilization of a finite resource of stock and propose to impose a tax on the harvest rate as an efficient mechanism with an aim at economic sustainability by incorporating the future opportunity of harvesting into the models as a major component of social objectives. The sensitivity analysis of the two-period model shows that (1) labor inputs for harvesting in Period 1 should be reduced, the biomass of fishery stock will increase, but the harvesting in Period 2 should be amplified and the biomass of fishery stock in Period 2 will not be affected if the current generation owns a higher valuation on the future opportunity of harvesting; (2) a higher internal regeneration rate leads to higher harvesting in each period and a higher level of fishery stock in Period 1, but an uncertain level of fishery stock in Period 2; (3) with a higher discount rate the harvesting in Period 1 should increase, but the harvesting in Period 2 should fall and the level of fishery stock in each period will be reduced; (4) a higher fish price in Period 1 leads to higher harvesting in Period 1, but reduced harvesting in Period 2. As a consequence, the level of fishery stock in each period will be reduced; (5) the effect of a change in fish prices in Period 2 on the harvesting and the level of fishery stock in Period 1 is uncertain, but the change in fish prices in Period 2 gives a positive effect on harvesting in Period 2 and a negative effect on the level of fishery stock in Period 2; (6) higher labor wages in Period 1 lead to lower harvesting, but a higher level of fishery stock in Period 1. This encourages an increase in harvesting in Period 2 and leads to a higher level of fishery stock in Period 2; and (7) a change of the labor wage in Period 2 affects the harvesting and the level of fishery stock in Period 1 indecisively, but it gives negative effects on the harvesting in Period 2 and positive effects on the level of fishery stock in Period 2.


Assuntos
Conservação dos Recursos Naturais , Pesqueiros/métodos , Peixes/crescimento & desenvolvimento , Modelos Teóricos , Animais , Humanos , Política Pública , Recursos Humanos
13.
J Chromatogr A ; 1104(1-2): 33-9, 2006 Feb 03.
Artigo em Inglês | MEDLINE | ID: mdl-16360664

RESUMO

A simple liquid-liquid-liquid microextraction with automated movement of the acceptor and the donor phase (LLLME/AMADP) technique is described for the quantitative determination of five phenoxyacetic acids in water using a disposable and ready to use hollow fiber. The target compounds were extracted from the acidified sample solution (donor phase) into the organic solvent residing in the pores of the hollow fiber and then back extracted into the alkaline solution (acceptor phase) inside the lumen of the hollow fiber. The fiber was held by a conventional 10-microl syringe. The acceptor phase was sandwiched between the plunger and a small volume of the organic solvent (microcap). The acceptor solution was repeatedly moved in and out of the hollow fiber assisted by a programmable syringe pump. This repeated movement provides a fresh acceptor phase to come in-contact with the organic phase and thus enhancing extraction kinetics leading to high enrichment of the analytes. The microcap separates the aqueous acceptor phase and the donor phase in addition of being partially responsible for mass transfer of the analytes from donor solution (moving in and out of the hollow fiber from the open end of the fiber) to the acceptor solution. Separation and quantitative analyses were then performed using liquid chromatography (LC) with ultraviolet (UV) detection at 280 nm. Various parameters affecting the extraction efficiency viz. type of organic solvent used for immobilization in the pores of the hollow fiber, extraction time, stirring speed, effect of sodium chloride, and concentration of donor and acceptor phases were studied. Repeatability (RSD, 3.2-7.4%), correlation coefficient (0.996-0.999), detection limit (0.2-2.8 ng ml(-1)) and enrichment factors (129-240) were also investigated. Relative recovery (87-101%) and absolute recoveries (4.6-13%) have also been calculated. The developed method was applied for the analysis of river water.


Assuntos
Acetatos/isolamento & purificação , Cromatografia Líquida/métodos , Acetatos/análise , Automação , Concentração Osmolar , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , Espectrofotometria Ultravioleta
14.
Environ Int ; 32(4): 478-86, 2006 May.
Artigo em Inglês | MEDLINE | ID: mdl-16380163

RESUMO

Taiwan's EPA has implemented a new guideline called the "Plastic Products Restriction Policy", prohibiting some industries to use plastics as packaging materials for the sake of sustainable use of resources. The significant effect resulting from this policy is the substitution of plastic products with paper products. Is this policy beneficial to achieve future sustainability? I attempt to analyze the resource choice between renewable resources and exhaustible resources for production of final products and services in case of exhaustion of natural resources. In this paper, I develop a framework to examine the dynamic responsiveness of a socio-economical system in facing a continual depletion of natural resources provided by an environmental system. In this framework, the status of an environmental system in terms of carrying capacity is affected by the cumulative impacts caused from human activities, including environmental pollution and resource exploitation. Conversely, it also affects the growth of renewable resources. This framework can serve as a guideline to construct indicators to measure the status of the environmental system and the socio-economical system in order to support a policy planner that formulates an appropriate environmental policy. Based on this framework, I also develop a mathematical model to determine the optimal ratio of resources choice between renewable resources and exhaustible resources.


Assuntos
Conservação dos Recursos Naturais , Técnicas de Apoio para a Decisão , Poluição Ambiental/prevenção & controle , Papel , Plásticos , Guias como Assunto , Formulação de Políticas , Política Pública , Taiwan
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