Abstract
Self-powered implantable devices have the potential to extend device operation time inside the body and reduce the necessity for high-risk repeated surgery. Without the technological ...innovation of in vivo energy harvesters driven by biomechanical energy, energy harvesters are insufficient and inconvenient to power titanium-packaged implantable medical devices. Here, we report on a commercial coin battery-sized high-performance inertia-driven triboelectric nanogenerator (I-TENG) based on body motion and gravity. We demonstrate that the enclosed five-stacked I-TENG converts mechanical energy into electricity at 4.9 μW/cm
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(root-mean-square output). In a preclinical test, we show that the device successfully harvests energy using real-time output voltage data monitored via Bluetooth and demonstrate the ability to charge a lithium-ion battery. Furthermore, we successfully integrate a cardiac pacemaker with the I-TENG, and confirm the ventricle pacing and sensing operation mode of the self-rechargeable cardiac pacemaker system. This proof-of-concept device may lead to the development of new self-rechargeable implantable medical devices.
A silk nanofiber‐networked bio‐triboelectric generator (Silk Bio‐TEG) is developed using an eco‐friendly and sustainable silk biomaterial with strong hydrogen bonding between peptide blocks. The ...electrospun Silk Bio‐TEG shows highly durable and reliable energy harvesting performances due to its notably high surface‐to‐volume ratio, mechanically super‐strong silk fibers, and fracture tolerant behavior of nanofiber‐networks.
Environmental perception plays an essential role in autonomous driving tasks and demands robustness in cluttered dynamic environments such as complex urban scenarios. In this paper, a robust Multiple ...Object Detection and Tracking (MODT) algorithm for a non-stationary base is presented, using multiple 3D LiDARs for perception. The merged LiDAR data is treated with an efficient MODT framework, considering the limitations of the vehicle-embedded computing environment. The ground classification is obtained through a grid-based method while considering a non-planar ground. Furthermore, unlike prior works, 3D grid-based clustering technique is developed to detect objects under elevated structures. The centroid measurements obtained from the object detection are tracked using Interactive Multiple Model-Unscented Kalman Filter-Joint Probabilistic Data Association Filter (IMM-UKF-JPDAF). IMM captures different motion patterns, UKF handles the nonlinearities of motion models, and JPDAF associates the measurements in the presence of clutter. The proposed algorithm is implemented on two slightly dissimilar platforms, giving real-time performance on embedded computers. The performance evaluation metrics by MOT16 and ground truths provided by KITTI Datasets are used for evaluations and comparison with the state-of-the-art. The experimentation on platforms and comparisons with state-of-the-art techniques suggest that the proposed framework is a feasible solution for MODT tasks.
With the recent developments in the efficiency of perovskite solar cells (PSCs), diverse functionalities are necessary for next‐generation charge‐transport layers. Specifically, the hole‐transport ...layer (HTL) in the various synthesized materials modified with functional groups is explored. A novel donor–acceptor type polymer, alkoxy‐PTEG, composed of benzo1,2‐b:4,5:b′dithiophene and tetraethylene glycol (TEG)‐substituted 2,1,3‐benzothiadiazole is reported. The alkoxy‐PTEG exhibits high solubility even in nonaromatic solvents, such as 3‐methylcyclohexanone (3‐MC), and can prevent possible lead leakage via chelation. The optical and electronic properties of alkoxy‐PTEG are thoroughly analyzed. Finally, a dopant‐free alkoxy‐PTEG device processed with 3‐MC exhibits 19.9% efficiency and a device with 2‐methyl anisole, which is a reported aromatic food additive, exhibits 21.2% efficiency in a tin oxide planar structure. The PSC device shows 88% stability after 30 d at ambient conditions (40–50% relative humidity and room temperature). In addition, nuclear magnetic resonance reveals that TEG groups can chelate lead ions with moderate strength (Kbinding = 2.76), and this strength is considered to be nondestructive to the perovskite lattice to prevent lead leakage. This is the first report to consider lead leakage and provide solutions to reduce this problem.
A dopant‐free alkoxy‐PTEG device processed with 3‐methylcyclohexanone exhibits 19.9% efficiency and a device with 2‐methyl anisole, which is a reported aromatic food additive, exhibits 21.2% efficiency. In addition, tetraethylene glycol groups can chelate lead ions with moderate strength (Kbinding = 2.76), and this strength is considered to be nondestructive to the perovskite lattice to prevent lead leakage.
With the application of organic–inorganic hybrid perovskites to liquid‐type solar cells, the unprecedented development of perovskite solar cells (Per‐SCs) has been boosted by the introduction of ...solid‐state hole transport materials (HTMs). The removal of liquid electrolyte has lead to improved efficiency and stability. Supported by high‐quality perovskite films, the certified efficiency of Per‐SCs has reached 25.2%. For Per‐SCs assembled in a conventional structure (n–i–p), the hole transport layer (HTL) plays an extra role in preventing the perovskite layer from external stimuli. In summary, the successful design and fabrication of the HTL must meet various requirements in terms of solubility, hole transport, recombination prevention, stability, and reproducibility, to name but a few. Many research strategies are focused on the development of high‐performance HTMs to meet such requirements. Such strategies for the development of HTMs employed in conventional n–i–p solar cells are reviewed herein. A vision of the future HTMs is proposed in this review based on the already proposed solutions and current trends.
Hole transport material (HTM) plays important roles in n–i–p type perovskite solar cells. It affects both efficiency and the stability. After the recognition of its importance, a number of HTMs have been developed. This review summarizes various types of HTMs and discusses their development.
In this paper, we report a new facile strategy to maximize the charge density for a high-output triboelectric nanogenerator (TENG). It was realized by designing a new cationic material structure ...consisting of SiO 2 and MoS 2 coated on a Ni-mesh in sequence. Compared with Ni-mesh-based TENGs, this new TENG generated about 13 times higher output power and a superior charge density of over 1000 μC m −2 with a slow charge decay rate. Its extremely high charge density could be explained by a low work function of MoS 2 , an upward bending of the energy band at the interface between MoS 2 and SiO 2 , and a high charge capacity of SiO 2 . Based on the gear-cam mode, the average output power of the TENG was measured to be about 14.75 W m -2 .
Electrochromic materials reversibly change colors by redox reactions depending on the oxidation states. To utilize electrochromic materials for active‐matrix display applications, an electrochromic ...display (ECD) requires simultaneous implementation of various colors and a fine‐pixelation process. Herein, flexible and transparent ECDs with simultaneously implementable subpixelated EC gels by sequential multiple patterning are successfully demonstrated. Ionic liquid‐based EC gels of monoheptyl‐viologen, diheptyl‐viologen (DHV), and diphenyl‐viologen (DPV) are used to create the colors of ECDs: magenta, blue, and green, respectively. Especially, to realize an improved green color, DHV–DPV composite gels are synthesized. Three EC gels exhibit stable properties without degradation during repetitive operation. Moreover, a transmittance greater than 90% is maintained in a bleached state, which is sufficient for application as a transparent display. The subpixelation process for multicolored‐flexible ECDs is designed to facilitate both easy fabrication and rapid operation with various patterns at low cost. The subpixelated EC gels using a film mask can be implemented to a minimum size of 200 µm. Furthermore, the subpixelated flexible ECDs exhibit high durability even after 1000 cycles of mechanical bending tests at a bending radius of 10 mm. Therefore, these EC materials can be used directly for flexible and transparent active‐matrix displays.
Flexible and transparent electrochromic displays (ECDs) with simultaneously implementable subpixelated EC gels by sequential multiple patterning are demonstrated. A transmittance greater than 90% is maintained in a bleached state, which is sufficient for transparent display. Moreover, the ECDs exhibit high durability after 1000 cycles of bending tests. These EC materials can be used directly for flexible and transparent active‐matrix displays.
Despite remarkable advances in computational chemistry, prediction of reaction mechanisms is still challenging, because investigating all possible reaction pathways is computationally prohibitive due ...to the high complexity of chemical space. A feasible strategy for efficient prediction is to utilize chemical heuristics. Here, we propose a novel approach to rapidly search reaction paths in a fully automated fashion by combining chemical theory and heuristics. A key idea of our method is to extract a minimal reaction network composed of only favorable reaction pathways from the complex chemical space through molecular graph and reaction network analysis. This can be done very efficiently by exploring the routes connecting reactants and products with minimum dissociation and formation of bonds. Finally, the resulting minimal network is subjected to quantum chemical calculations to determine kinetically the most favorable reaction path at the predictable accuracy. As example studies, our method was able to successfully find the accepted mechanisms of Claisen ester condensation and cobalt-catalyzed hydroformylation reactions.
Haploinsufficiency of ANKRD11 due to deletion or truncation mutations causes KBG syndrome, a rare genetic disorder characterized by intellectual disability, autism spectrum disorder, and craniofacial ...abnormalities. However, little is known about the neurobiological role of ANKRD11 during brain development. Here we show that ANKRD11 regulates pyramidal neuron migration and dendritic differentiation in the developing mouse cerebral cortex. Using an in utero manipulation approach, we found that Ankrd11 knockdown delayed radial migration of cortical neurons. ANKRD11-deficient neurons displayed markedly reduced dendrite growth and branching as well as abnormal dendritic spine morphology. Ankrd11 knockdown suppressed acetylation of epigenetic molecules such as p53 and Histone H3. Furthermore, the mRNA levels of Trkb, Bdnf, and neurite growth-related genes were downregulated in ANKRD11-deficient cortical neurons. The Trkb promoter region was largely devoid of acetylated Histone H3 and p53, and was instead occupied with MeCP2 and DNMT1. Overexpression of TrkB rescued abnormal dendrite growth in these cells. Our findings demonstrate a novel role for ANKRD11 in neuron differentiation during brain development and suggest an epigenetic modification as a potential key molecular feature underlying KBG syndrome.
•ANKRD11 is required for cortical dendrite growth and arborization during brain development.•ANKRD11 regulates acetylation of epigenetic molecules such as p53 and Histone H3 at the Trkb promoter.•Expression of Trkb, Bdnf, and neurite growth-related genes are regulated by ANKRD11.•Overexpression of TrkB rescues abnormal dendrite development in ANKRD11-deficient neurons.•Our study provides insight into the pathogenic mechanism underlying KBG syndrome.
Bismuth vanadate (BiVO4) has a band structure that is well-suited for potential use as a photoanode in solar water splitting, but it suffers from poor electron-hole separation. Here, we demonstrate ...that a nanoporous morphology (specific surface area of 31.8 square meters per gram) effectively suppresses bulk carrier recombination without additional doping, manifesting an electron-hole separation yield of 0.90 at 1.23 volts (V) versus the reversible hydrogen electrode (RHE). We enhanced the propensity for surface-reaching holes to instigate water-splitting chemistry by serially applying two different oxygen evolution catalyst (OEC) layers, FeOOH and NiOOH, which reduces interface recombination at the BiVO4/OEC junction while creating a more favorable Helmholtz layer potential drop at the OEC/electrolyte junction. The resulting BiVO4/FeOOH/NiOOH photoanode achieves a photocurrent density of 2.73 milliamps per square centimenter at a potential as low as 0.6 V versus RHE.
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