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1.
Biosens Bioelectron ; 139: 111296, 2019 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-31128480

RESUMO

Remarkable research efforts have been devoted to replicate the tactile sensitivity of human skin. Unfortunately, so far flexible pressure sensors reported barely fit the tactile requirements for fingertips, which could endure a pressure over 100 kPa and also can sense a gentle touch. It is vital to develop flexible pressure sensors which can ensure high sensitivity and wide operation range simultaneously, to satisfy the demands of mimicking the pressure sensing function of fingertips. In this work, a mini-size, light-weight but high-performance graphene film based pressure sensor is presented. Owing to the advanced structure with fluctuations on surface and fluffy-layered structure in cross-section of the graphene film, this pressure sensor shows an extraordinary performance of high sensitivity of 10.39 kPa-1 (0-2 kPa), ultra-wide operation range up to 200 kPa, impressively stable repeatability, high working frequency, rapid response and recovery time. Moreover, the demonstrated results of the detection of traditional Chinese medicine wrist-pulse waveform and the bionic fingertip tactile sensors, suggest the great application potential of the obtain device in biomedical field and bionic skins field.


Assuntos
Biônica/métodos , Técnicas Biossensoriais , Pele/química , Dispositivos Eletrônicos Vestíveis , Grafite/química , Humanos , Medicina Tradicional Chinesa , Pressão
2.
Philos Trans A Math Phys Eng Sci ; 377(2138): 20180263, 2019 Feb 11.
Artigo em Inglês | MEDLINE | ID: mdl-30967069

RESUMO

To save energy and reduce environmental impacts, new technologies towards a development of a sustainable 'greener' economy are needed. The main opportunity to improve sustainability by reducing emissions is within the transport sector. More than 90% of all goods worldwide are transported by ships. Particularly maritime ships using heavy fuel oil and marine gas oil play a major role. The total fuel consumption of shipping in 2016 was about 250 m t (domestic ca. 50 m t, international shipping ca. 200 m t). The vast portion of the energy consumption of a ship is the need to overcome the drag between ship hull and water-depending on the shape of the vessel and its size up to 90% of total fuel consumption. This means reducing drag helps to save fuel and reduces carbon emissions as well as pollution considerably. Different techniques for drag reduction are known, e.g. the micro-bubble technique or the bulbous bow. We investigated a novel bioinspired technique since 2002: the application of biomimetic surfaces with long-term stable air layers on ship hulls, serving as a slip agent. This technology is based on the Salvinia Effect, allowing a permanent stabilization of air layers under water. In this case study, we analysed the possible savings, which also could be combined with modified micro-bubble technologies. We calculated, based on a selection of five ship types, representing 75% of the world fleet, that air-layer hull coatings could lead to estimated savings of 32.5 million tons of fuel (meaning 13.0% of the worldwide shipping fuel consumption), equal to 18.5 billion US$ and 130.0 million tons of CO2e per year. The positive impacts on global temperature and other greenhouse gases are calculated and could be a contributing factor in accomplishing the UN Sustainable Development Goals and the Paris Agreement to the UN Framework Convention on Climate Change. The study is a contribution to enhance our patchy knowledge concerning the potential economic and ecological benefit of bionics and biomimetic technologies. This article is part of the theme issue 'Bioinspired materials and surfaces for green science and technology'.


Assuntos
Ar , Biônica/métodos , Combustíveis Fósseis , Oceanos e Mares , Navios , Desenvolvimento Sustentável , Água , Biônica/economia , Mudança Climática , Custos e Análise de Custo , Hidrodinâmica , Desenvolvimento Sustentável/economia
3.
Biosens Bioelectron ; 130: 254-261, 2019 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-30771714

RESUMO

Urolithiasis commonly occurs in kidney and ureteral, and may cause local organ/tissue damage, even kidney failure. The incidence of this disease is increasing worldwide, in which calcium oxalate is the major composition forming the urinary calculus. Therefore, to monitor this disease for the prevention and treatment, measuring the oxalate in the urine is of great significance. Here, a rapid and sensitive colorimetric method was developed based on 3,3',5,5'-tetramethylbenzidine-manganese dioxide (TMB-MnO2) nanosheets for oxalate detection. MnO2 nanosheets acted as an efficient biomimetic oxidase to catalyze the reaction with TMB and oxalate. Pale yellow TMB can be oxidized to blue oxide TMB catalyzed by BSA-stabilized MnO2 nanosheets, and oxalate can selectively inhibit this reaction by consuming and reacting with MnO2 nanosheets, thus achieving the quantitative detection of oxalate. Moreover, a home-made bionic electronic-eye (E-eye) system was developed as a portable in-situ detection platform to efficiently measure the oxalate concentrations in 10 s by direct photographing. By optimizing experimental conditions, this method shows a wide linear range (7.8 µM to 250 µM) and a low detection limit (0.91 µM) for oxalate detection. Besides, this method exhibits high selectivity even with 80-fold interfering chemicals. Furthermore, the performance of the method was validated by testing the artificial urine samples, indicating its great potential for monitoring and diagnosis of urolithiasis in point-of-care applications.


Assuntos
Biônica/métodos , Técnicas Biossensoriais , Oxalatos/isolamento & purificação , Oxirredutases/química , Biomimética , Colorimetria , Glutationa/química , Humanos , Limite de Detecção , Nanoestruturas/química , Oxalatos/química , Oxirredução
4.
Cleve Clin J Med ; 85(12): 931-937, 2018 12.
Artigo em Inglês | MEDLINE | ID: mdl-30526754

RESUMO

Research continues toward the goal of treating type 1 diabetes by replacing insulin-producing beta cells. Ideally, such treatment would be safe and long-lasting and would eliminate the need for subcutaneous insulin replacement. This article reviews the current state of beta-cell replacement through transplant of the whole pancreas or of islet cells. It also looks at the "bionic" pancreas and other future challenges.


Assuntos
Biônica/métodos , Diabetes Mellitus Tipo 1/cirurgia , Células Secretoras de Insulina/transplante , Transplante das Ilhotas Pancreáticas/tendências , Transplante de Pâncreas/tendências , Humanos
5.
Nano Lett ; 18(12): 7448-7456, 2018 12 12.
Artigo em Inglês | MEDLINE | ID: mdl-30403141

RESUMO

Investigating the multidimensional integration between different microbiological kingdoms possesses potential toward engineering next-generation bionic architectures. Bacterial and fungal kingdom exhibits mutual symbiosis that can offer advanced functionalities to these bionic architectures. Moreover, functional nanomaterials can serve as probing agents for accessing newer information from microbial organisms due to their dimensional similarities. In this article, a bionic mushroom was created by intertwining cyanobacterial cells with graphene nanoribbons (GNRs) onto the umbrella-shaped pileus of mushroom for photosynthetic bioelectricity generation. These seamlessly merged GNRs function as agents for mediating extracellular electron transport from cyanobacteria resulting in photocurrent generation. Additionally, three-dimensional (3D) printing technique was used to assemble cyanobacterial cells in anisotropic, densely packed geometry resulting in adequate cell-population density for efficient collective behavior. These 3D printed cyanobacterial colonies resulted in comparatively higher photocurrent (almost 8-fold increase) than isotropically casted cyanobacteria of similar seeding density. An insight of the proposed integration between cyanobacteria and mushroom derives remarkable advantage that arises from symbiotic relationship, termed here as engineered bionic symbiosis. Existence of this engineered bionic symbiosis was confirmed by UV-visible spectroscopy and standard plate counting method. Taken together, the present study augments scientific understanding of multidimensional integration between the living biological microworld and functional abiotic nanomaterials to establish newer dimensionalities toward advancement of bacterial nanobionics.


Assuntos
Fontes de Energia Bioelétrica/microbiologia , Cianobactérias/citologia , Nanoestruturas/química , Nanotecnologia/métodos , Impressão Tridimensional , Biônica/métodos , Células Imobilizadas/citologia , Células Imobilizadas/metabolismo , Cianobactérias/metabolismo , Transporte de Elétrons , Fotossíntese
6.
ACS Appl Mater Interfaces ; 10(36): 30689-30697, 2018 Sep 12.
Artigo em Inglês | MEDLINE | ID: mdl-30003780

RESUMO

In recent years, wearable and flexible sensors have attracted considerable research interest and effort owing to their broad application prospects in wearable devices, robotics, health monitoring, and so on. High-sensitivity and low-cost pressure sensors are the primary requirement in practical application. Herein, a convenient and low-cost process to fabricate a bionic fish-scale structure poly(dimethylsiloxane) (PDMS) film via air/water interfacial formation technique is presented. High-sensitivity flexible pressure sensors can be constructed by assembling conductive films of graphene nanosheets into a microstructured film. Thanks to the unique fish-scale structures of PDMS films, the prepared pressure sensor shows excellent performance with high sensitivity (-70.86% kPa-1). In addition, our pressure sensors can detect weak signals, such as wrist pulses, respiration, and voice vibrations. Moreover, the whole process of pressure sensor preparation is cost-effective, eco-friendly, and controllable. The results indicate that the prepared pressure sensor has a profitable and efficient advantage in future applications for monitoring human physiological signals and sensing subtle touch, which may broaden its potential applications in wearable devices.


Assuntos
Biônica/métodos , Pressão , Dispositivos Eletrônicos Vestíveis , Ar , Escamas de Animais , Animais , Grafite/química , Humanos , Nanoestruturas , Água/química
7.
Mil Med Res ; 5(1): 8, 2018 02 26.
Artigo em Inglês | MEDLINE | ID: mdl-29502534

RESUMO

BACKGROUND: Noise exposure can lead to hearing loss and multiple system dysfunctions. As various forms of noise exist in our living environments, and our auditory organs are very sensitive to acoustic stimuli, it is a challenge to protect our hearing system in certain noisy environments. PRESENTATION OF THE HYPOTHESIS: Herein, we propose that our hearing organ could serve as a noise eliminator for high intensity noise and enhance acoustic signal processing abilities by increasing the signal-noise ratio. For suprathreshold signals, the hearing system is capable of regulating the middle ear muscles and other structures to actively suppress the sound level to a safe range. TESTING THE HYPOTHESIS: To test our hypothesis, both mathematic model analyses and animal model studies are needed. Based on a digital 3D reconstructed model, every structure in the auditory system can be analyzed and tested for its contribution to the process of noise reduction. Products manufactured by this bionic method could be used and verified in animal models and volunteers. IMPLICATIONS: By mimicking the noise-reduction effect of the sophisticated structures in the hearing system, we may be able to provide a model that establishes a new active-sound-suppression mode. This innovative method may overcome the limited capabilities of current noise protection options and become a promising possibility for noise prevention.


Assuntos
Biônica/métodos , Audição/fisiologia , Ruído/prevenção & controle , Estimulação Acústica/métodos , Biônica/tendências , Humanos , Ruído/efeitos adversos
8.
J Neural Eng ; 15(4): 046015, 2018 08.
Artigo em Inglês | MEDLINE | ID: mdl-29595147

RESUMO

OBJECTIVE: Neural stimulation is usually performed with fairly large platinum electrodes. Smaller electrodes increase the applied charge density, potentially damaging the electrode. Greater understanding of the charge injection mechanism is required for safe neural stimulation. APPROACH: The charge injection mechanism and charge injection capacity were measured by cyclic voltammetry. Electrodes were cleaned mechanically or by potential cycling in acidic solutions. The effective electrode area was measured by hydrogen adsorption or reduction of [Formula: see text]. MAIN RESULTS: The water window and safe potential window were affected by changes to electrolyte, electrode size, polishing method and oxygen concentration. Capacitance and Faradaic current contribute to the charge injection capacity. Varying voltammetric scan rate (measurement time), electrode size, polishing method, potential window, electrolyte and oxygen concentration affected the charge injection capacity and ratio of oxidation to reduction charge. Hydrogen adsorption in acidic solutions provided an inaccurate effective electrode area. Reduction of a solution phase redox species with a linear or radial diffusion profile could provide an effective electrode area. The charge density (charge injection capacity divided by electrode area) of a platinum electrode is dependent on the charge injection capacity and electrode area measurement technique. By varying cyclic voltammetric conditions, the charge density of platinum ranged from 0.15 to 5.57 mC cm-2. SIGNIFICANCE: The safe potential window, charge injection mechanism, charge injection capacity and charge density of platinum depends on electrolyte, size of the electrode, oxygen concentration and differences in electrode polishing method. The oxidation and reduction charge injection capacities are not equal. Careful control of a platinum electrodes surface may allow larger charge densities and safe use of smaller electrodes. New electrode materials and geometries should be tested in a consistent manner to allow comparison of potential suitability for neural stimulation.


Assuntos
Biônica/métodos , Técnicas Eletroquímicas/métodos , Eletrodos , Desenho de Equipamento/métodos , Platina/química , Biônica/instrumentação , Biônica/normas , Técnicas Eletroquímicas/instrumentação , Técnicas Eletroquímicas/normas , Eletrodos/normas , Desenho de Equipamento/normas , Cloreto de Sódio/química
9.
Sensors (Basel) ; 18(4)2018 Mar 30.
Artigo em Inglês | MEDLINE | ID: mdl-29601531

RESUMO

Based on bionic compound eye and human foveated imaging mechanisms, a hybrid bionic image sensor (HBIS) is proposed in this paper to extend the field of view (FOV) with high resolution. First, the hybrid bionic imaging model was developed and the structure parameters of the HBIS were deduced. Second, the properties of the HBIS were simulated, including FOV extension, super-resolution imaging, foveal ratio and so on. Third, a prototype of the HBIS was developed to validate the theory. Imaging experiments were carried out, and the results are in accordance with the simulations, proving the potential of the HBIS for large FOV and high-resolution imaging with low cost.


Assuntos
Biônica/métodos , Fóvea Central
10.
J Biomed Mater Res A ; 106(6): 1664-1676, 2018 06.
Artigo em Inglês | MEDLINE | ID: mdl-29460433

RESUMO

Articular cartilage (AC) has gradient features in both mechanics and histology as well as a poor regeneration ability. The repair of AC poses difficulties in both research and the clinic. In this paper, a gradient scaffold based on poly(lactic-co-glycolic acid) (PLGA)-extracellular matrix was proposed. Cartilage scaffolds with a three-layer gradient structure were fabricated by PLGA through three-dimensional printing, and the microstructure orientation and pore fabrication were made by decellularized extracellular matrix injection and directional freezing. The manufactured scaffold has a mechanical strength close to that of real cartilage. A quantitative optimization of the Young's modulus and shear modulus was achieved by material mechanics formulas, which achieved a more accurate mechanical bionic and a more stable interface performance because of the one-time molding process. At the same time, the scaffolds have a bionic and gradient microstructure orientation and pore size, and the stratification ratio can be quantitatively optimized by design of the freeze box and temperature simulation. In general, this paper provides a method to optimize AC scaffolds by both mechanics and histology as well as a bionic multimaterial scaffold. This paper is of significance for cell culture and clinical transplantation experiments. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 106A: 1664-1676, 2018.


Assuntos
Materiais Biocompatíveis/química , Cartilagem Articular/citologia , Matriz Extracelular/química , Copolímero de Ácido Poliláctico e Ácido Poliglicólico/química , Engenharia Tecidual/métodos , Tecidos Suporte/química , Animais , Biônica/métodos , Módulo de Elasticidade , Liofilização , Congelamento , Teste de Materiais , Porosidade , Impressão Tridimensional , Suínos
11.
Talanta ; 179: 145-152, 2018 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-29310214

RESUMO

Preparation of high performance electrochemical biosensing interface for the sensitive and rapid detection of human metabolites is of great interest for health care and biomedical science. In this paper, based on the adhesion technique of marine mussels, we designed and prepared a novel biosensor with a micro/nano-biointerface of Fe3O4-Mn3(PO3)2@Ni foam, which offered a three dimensional (3D) living environment for real cell. The constructed biosensor with a 3D micro/nano-biointerface of Fe3O4-Mn3(PO3)2@Ni foam was characterized by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and elemental mapping. Furthermore, the electrochemical experiments by electrochemical method for detection of superoxide anion (O2•-) in situ released by cells were carried out by this biosensor we proposed. Results indicated that the 3D interface of mussel-inspired Fe3O4-Mn3(PO3)2@Ni foam offered an amicable platform for promoting cell adhesion, which was beneficial for enhancing biosensing activity. This proposed sensing platform provided high electroactivity and excellent electron transport with a lower detection limit (0.0170µM), wider linear range 0.04-2.44µM) and short diffusion distance to reaction sites. The case achieved the accurate detection of O2•- (in situ released by cells) based on the combination of mussel-inspired biomimetic adhesion technique, 3D micro/nano-biointerface construction and electrochemical biosensing technique.


Assuntos
Técnicas Biossensoriais , Técnicas Eletroquímicas , Óxido Ferroso-Férrico/química , Superóxidos/análise , Substâncias Viscoelásticas/química , Células A549 , Animais , Biônica/métodos , Bivalves/química , Sobrevivência Celular/efeitos dos fármacos , Óxido Ferroso-Férrico/farmacologia , Humanos , Níquel/química , Níquel/farmacologia , Compostos Organometálicos/química , Compostos Organometálicos/farmacologia , Superóxidos/metabolismo
12.
Spinal Cord ; 56(2): 106-116, 2018 02.
Artigo em Inglês | MEDLINE | ID: mdl-29105657

RESUMO

STUDY DESIGN: Prospective quasi-experimental study, pre- and post-design. OBJECTIVES: Assess safety, feasibility, training characteristics and changes in gait function for persons with spinal cord injury (SCI) using the robotic exoskeletons from Ekso Bionics. SETTING: Nine European rehabilitation centres. METHODS: Robotic exoskeleton gait training, three times weekly over 8 weeks. Time upright, time walking and steps in the device (training characteristics) were recorded longitudinally. Gait and neurological function were measured by 10 Metre Walk Test (10 MWT), Timed Up and Go (TUG), Berg Balance Scale (BBS), Walking Index for Spinal Cord Injury (WISCI) II and Lower Extremity Motor Score (LEMS). RESULTS: Fifty-two participants completed the training protocol. Median age: 35.8 years (IQR 27.5-52.5), men/women: N = 36/16, neurological level of injury: C1-L2 and severity: AIS A-D (American Spinal Injury Association Impairment Scale). Time since injury (TSI) < 1 year, N = 25; > 1 year, N = 27. No serious adverse events occurred. Three participants dropped out following ankle swelling (overuse injury). Four participants sustained a Category II pressure ulcer at contact points with the device but completed the study and skin normalized. Training characteristics increased significantly for all subgroups. The number of participants with TSI < 1 year and gait function increased from 20 to 56% (P = 0.004) and 10MWT, TUG, BBS and LEMS results improved (P < 0.05). The number of participants with TSI > 1 year and gait function, increased from 41 to 44% and TUG and BBS results improved (P < 0.05). CONCLUSIONS: Exoskeleton training was generally safe and feasible in a heterogeneous sample of persons with SCI. Results indicate potential benefits on gait function and balance.


Assuntos
Biônica/métodos , Terapia por Exercício/métodos , Exoesqueleto Energizado , Marcha/fisiologia , Traumatismos da Medula Espinal/reabilitação , Adolescente , Adulto , Idoso , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Traumatismos da Medula Espinal/fisiopatologia , Resultado do Tratamento , Adulto Jovem
13.
J Rehabil Med ; 50(2): 173-180, 2018 Feb 13.
Artigo em Inglês | MEDLINE | ID: mdl-29068039

RESUMO

OBJECTIVE: To investigate the effects of overground bionic ambulation with variable assistance on cardiorespiratory and metabolic responses in persons with motor-incomplete spinal cord injury. DESIGN: Case series. SUBJECTS: Four participants with chronic, motor-incomplete spinal cord injury. METHODS: Subjects completed a maximal graded exercise test on an arm-ergometer and 3 6-min bouts of overground bionic ambulation using different modes of assistance, i.e. Maximal, Adaptive, Fixed. Cardiorespiratory (oxygen consumption) and metabolic (caloric expenditure and substrate utilization) measures were taken using a mobile metabolic cart at each overground bionic ambulation assistance. RESULTS: Cardiorespiratory responses ranged from low (24% VO2peak) for the least impaired and fittest individual to supramaximal (124% VO2peak) for the participant with the largest impairments and the lowest level of fitness. Different overground bionic ambulation assistive modes elicited small (3-8% VO2peak) differences in cardiorespiratory responses for 3 participants. One participant had a large (28% VO2peak) difference in cardiorespiratory responses to different modes of overground bionic ambulation. Metabolic responses mostly tracked closely with cardiorespiratory responses. Total energy expenditure ranged from 1.39 to 7.17 kcal/min. Fat oxidation ranged from 0.00 to 0.17 g/min across participants and different overground bionic ambulation modes. CONCLUSION: Overground bionic ambulation with variable assistance can substantially increase cardiorespiratory and metabolic responses; however, these responses vary widely across participants and overground bionic ambulation modes.


Assuntos
Biônica/métodos , Traumatismos da Medula Espinal/complicações , Caminhada/fisiologia , Adulto , Feminino , Humanos , Pessoa de Meia-Idade
14.
Trends Biotechnol ; 36(5): 483-487, 2018 05.
Artigo em Inglês | MEDLINE | ID: mdl-29224718

RESUMO

Bio-inspired engineering applies biological design principles towards developing engineering solutions but is not practical as a manufacturing paradigm. We advocate 'bionic manufacturing', a synergistic fusion of biotic and abiotic components, to transition away from bio-inspiration toward bio-augmentation to address current limitations in bio-inspired manufacturing.


Assuntos
Células Artificiais , Órgãos Artificiais/tendências , Biônica/métodos , Biônica/tendências , Humanos
16.
J Vis Exp ; (126)2017 08 14.
Artigo em Inglês | MEDLINE | ID: mdl-28829413

RESUMO

In this manuscript, we present two 'Bionic Clicker' systems, the first designed to demonstrate electromyography (EMG) based control systems for educational purposes and the second for research purposes. EMG based control systems pick up electrical signals generated by muscle activation and use these as inputs for controllers. EMG controllers are widely used in prosthetics to control limbs. The Mark I (MK I) clicker allows the wearer to change the slide of a presentation by raising their index finger. It is built around a microcontroller and a bio-signals shield. It generated a lot of interest from both the public and research community. The Mark II (MK II) device presented here was designed to be a cheaper, sleeker, and more customizable system that can be easily modified and directly transmit EMG data. It is built using a wireless capable microcontroller and a muscle sensor.


Assuntos
Biônica/instrumentação , Eletromiografia/instrumentação , Biônica/métodos , Desenho de Equipamento , Dedos/fisiologia , Humanos , Impressão Tridimensional , Tecnologia sem Fio
17.
Theranostics ; 7(9): 2509-2523, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28744331

RESUMO

Urethral strictures remain a reconstructive challenge, due to less than satisfactory outcomes and high incidence of stricture recurrence. An "ideal" urethral reconstruction should establish similar architecture and function as the original urethral wall. We fabricated a novel tissue-engineered bionic urethras using cell sheet technology and report their viability in a canine model. Small amounts of oral and adipose tissues were harvested, and adipose-derived stem cells, oral mucosal epithelial cells, and oral mucosal fibroblasts were isolated and used to prepare cell sheets. The cell sheets were hierarchically tubularized to form 3-layer tissue-engineered urethras and labeled by ultrasmall super-paramagnetic iron oxide (USPIO). The constructed tissue-engineered urethras were transplanted subcutaneously for 3 weeks to promote the revascularization and biomechanical strength of the implant. Then, 2 cm length of the tubularized penile urethra was replaced by tissue-engineered bionic urethra. At 3 months of urethral replacement, USPIO-labeled tissue-engineered bionic urethra can be effectively detected by MRI at the transplant site. Histologically, the retrieved bionic urethras still displayed 3 layers, including an epithelial layer, a fibrous layer, and a myoblast layer. Three weeks after subcutaneous transplantation, immunofluorescence analysis showed the density of blood vessels in bionic urethra was significantly increased following the initial establishment of the constructs and was further up-regulated at 3 months after urethral replacement and was close to normal level in urethral tissue. Our study is the first to experimentally demonstrate 3-layer tissue-engineered urethras can be established using cell sheet technology and can promote the regeneration of structural and functional urethras similar to normal urethra.


Assuntos
Meios de Contraste/metabolismo , Dextranos/metabolismo , Técnicas de Cultura de Órgãos , Engenharia Tecidual/métodos , Uretra/fisiologia , Animais , Biônica/métodos , Cães , Células Epiteliais/fisiologia , Fibroblastos/fisiologia , Imunofluorescência , Imagem por Ressonância Magnética , Nanopartículas de Magnetita , Coloração e Rotulagem/métodos , Células-Tronco/fisiologia , Transplantes/fisiologia
18.
J Neuroeng Rehabil ; 14(1): 35, 2017 04 27.
Artigo em Inglês | MEDLINE | ID: mdl-28449684

RESUMO

BACKGROUND: Powered ankle-foot exoskeletons can reduce the metabolic cost of human walking to below normal levels, but optimal assistance properties remain unclear. The purpose of this study was to test the effects of different assistance timing and power characteristics in an experiment with a tethered ankle-foot exoskeleton. METHODS: Ten healthy female subjects walked on a treadmill with bilateral ankle-foot exoskeletons in 10 different assistance conditions. Artificial pneumatic muscles assisted plantarflexion during ankle push-off using one of four actuation onset timings (36, 42, 48 and 54% of the stride) and three power levels (average positive exoskeleton power over a stride, summed for both legs, of 0.2, 0.4 and 0.5 W∙kg-1). We compared metabolic rate, kinematics and electromyography (EMG) between conditions. RESULTS: Optimal assistance was achieved with an onset of 42% stride and average power of 0.4 W∙kg-1, leading to 21% reduction in metabolic cost compared to walking with the exoskeleton deactivated and 12% reduction compared to normal walking without the exoskeleton. With suboptimal timing or power, the exoskeleton still reduced metabolic cost, but substantially less so. The relationship between timing, power and metabolic rate was well-characterized by a two-dimensional quadratic function. The assistive mechanisms leading to these improvements included reducing muscular activity in the ankle plantarflexors and assisting leg swing initiation. CONCLUSIONS: These results emphasize the importance of optimizing exoskeleton actuation properties when assisting or augmenting human locomotion. Our optimal assistance onset timing and average power levels could be used for other exoskeletons to improve assistance and resulting benefits.


Assuntos
Tornozelo , Biônica/métodos , Exoesqueleto Energizado , , Músculo Esquelético/fisiologia , Caminhada/fisiologia , Fenômenos Biomecânicos , Biônica/instrumentação , Eletromiografia , Feminino , Marcha/fisiologia , Voluntários Saudáveis , Humanos , Perna (Membro)/fisiologia , Metabolismo , Desenho de Prótese , Robótica , Adulto Jovem
19.
Bioinspir Biomim ; 12(2): 026007, 2017 02 15.
Artigo em Inglês | MEDLINE | ID: mdl-28091394

RESUMO

Modern cars are equipped with both active and passive sensor systems that can detect potential collisions. In contrast, locusts avoid collisions solely by responding to certain visual cues that are associated with object looming. In neurophysiological experiments, I investigated the possibility that the 'collision-detector neurons' of locusts respond to impending collisions in films recorded with dashboard cameras of fast driving cars. In a complementary modelling approach, I developed a simple algorithm to reproduce the neuronal response that was recorded during object approach. Instead of applying elaborate algorithms that factored in object recognition and optic flow discrimination, I tested the hypothesis that motion detection restricted to a 'danger zone', in which frontal collisions on the motorways are most likely, is sufficient to estimate the risk of a collision. Furthermore, I investigated whether local motion vectors, obtained from the differential excitation of simulated direction-selective networks, could be used to predict evasive steering maneuvers and prevent undesired responses to motion artifacts. The results of the study demonstrate that the risk of impending collisions in real traffic scenes is mirrored in the excitation of the collision-detecting neuron (DCMD) of locusts. The modelling approach was able to reproduce this neuronal response even when the vehicle was driving at high speeds and image resolution was low (about 200 × 100 pixels). Furthermore, evasive maneuvers that involved changing the steering direction and steering force could be planned by comparing the differences in the overall excitation levels of the simulated right and left direction-selective networks. Additionally, it was possible to suppress undesired responses of the algorithm to translatory movements, camera shake and ground shadows by evaluating local motion vectors. These estimated collision risk values and evasive steering vectors could be used as input for a driving assistant, converting the first into braking force and the latter into steering responses to avoid collisions. Since many processing steps were computed on the level of pixels and involved elements of direction-selective networks, this algorithm can be implemented in hardware so that parallel computations enhance the processing speed significantly.


Assuntos
Acidentes de Trânsito/prevenção & controle , Algoritmos , Biomimética , Gafanhotos/fisiologia , Percepção de Movimento/fisiologia , Neurônios/fisiologia , Animais , Condução de Veículo , Biônica/métodos , Eletrodos Implantados , Voo Animal/fisiologia , Filmes Cinematográficos , Navegação Espacial/fisiologia , Percepção Visual
20.
Nat Mater ; 16(2): 264-272, 2017 02.
Artigo em Inglês | MEDLINE | ID: mdl-27798623

RESUMO

Plant nanobionics aims to embed non-native functions to plants by interfacing them with specifically designed nanoparticles. Here, we demonstrate that living spinach plants (Spinacia oleracea) can be engineered to serve as self-powered pre-concentrators and autosamplers of analytes in ambient groundwater and as infrared communication platforms that can send information to a smartphone. The plants employ a pair of near-infrared fluorescent nanosensors-single-walled carbon nanotubes (SWCNTs) conjugated to the peptide Bombolitin II to recognize nitroaromatics via infrared fluorescent emission, and polyvinyl-alcohol functionalized SWCNTs that act as an invariant reference signal-embedded within the plant leaf mesophyll. As contaminant nitroaromatics are transported up the roots and stem into leaf tissues, they accumulate in the mesophyll, resulting in relative changes in emission intensity. The real-time monitoring of embedded SWCNT sensors also allows residence times in the roots, stems and leaves to be estimated, calculated to be 8.3 min (combined residence times of root and stem) and 1.9 min mm-1 leaf, respectively. These results demonstrate the ability of living, wild-type plants to function as chemical monitors of groundwater and communication devices to external electronics at standoff distances.


Assuntos
Engenharia Genética/métodos , Hidrocarbonetos Aromáticos/metabolismo , Compostos de Nitrogênio/metabolismo , Peptídeos/metabolismo , Plantas Geneticamente Modificadas/fisiologia , Spinacia oleracea/fisiologia , Biônica/métodos , Substâncias Explosivas/análise , Hidrocarbonetos Aromáticos/análise , Raios Infravermelhos , Nanotubos de Carbono/química , Compostos de Nitrogênio/análise , Peptídeos/genética
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