31 research outputs found
Candida tropicalis arthritis of the elbow in a patient with Ewing's sarcoma that successfully responded to itraconazole
Fungal infections are rarely responsible for arthritis. Few cases of fungal arthritis have been reported, even in immunocompromised hosts susceptible to low-virulence organisms. Herein, the authors report the first case of Candida tropicalis arthritis in a child with a solid tumor. A 13-year-old boy with Ewing's sarcoma developed arthritis in his elbow during the neutropenic period after chemotherapy. Despite treatment with broad-spectrum antibiotics, his condition did not improve and serial blood cultures failed to reveal any causative organisms. After surgical drainage, culture of the joint fluid revealed the presence of C. tropicalis. Itraconazole treatment was started and after 3 months of therapy, the patient completely recovered full elbow function
Stretchy Electrochemical Harvesters for Binarized Self-Powered Strain Gauge-Based Static Motion Sensors
The human monitoring system has motivated the search for new technology, leading to the development of a self-powered strain sensor. We report on the stretchable and soft stretchy electrochemical harvester (SECH) bilayer for a binarized self-powered strain gauge in dynamic and static motion. The active surface area participating in the electrochemical reaction was enhanced after stretching the SECH in the electrolyte, leading to an increase in the electrochemical double-layer capacitance. A change in the capacitance induced a change in the electrical potential of the bilayer, generating electrical energy. The SECH overcomes several challenges of the previous mechano-electrochemical harvester: The harvester had high elasticity (50%), which satisfied the required strain during human motion. The harvester was highly soft (modulus of 5.8 MPa), 103 times lower than that of the previous harvester. The SECH can be applied to a self-powered strain gauge, capable of measuring stationary deformation and low-speed motion. The SECH created a system to examine the configuration of the human body, as demonstrated by the human monitoring sensor from five independent SECH assembled on the hand. Furthermore, the sensing information was simplified through the binarized signal. It can be used to assess the hand configuration for hand signals and sign language
Harvesting electrical energy from torsional thermal actuation driven by natural convection
The development of practical, cost-efective systems for the conversion of low-grade waste heat to electrical energy is an important area of renewable energy research. We here demonstrate a thermal energy harvester that is driven by the small temperature fuctuations provided by natural convection. This harvester uses coiled yarn artifcial muscles, comprising well-aligned shape memory polyurethane (SMPU) microfbers, to convert thermal energy to torsional mechanical energy, which is then electromagnetically converted to electrical energy. Temperature fuctuations in a yarn muscle, having a maximum hot-to-cold temperature diference of about 13°C, were used to spin a magnetic rotor to a peak torsional rotation speed of 3,000rpm. The electromagnetic energy generator converted the torsional energy to electrical energy, thereby producing an oscillating output voltage of up to 0.81V and peak power of 4W/kg, based on SMPU mass
Elastomeric and dynamic MnO2/CNT core-shell structure coiled yarn supercapacitor
Reversibly deformable and highly performing solid-state yarn supercapacitors are obtained using MnO2-deposited microcoiled yarn electrodes. The core(CNT)-shell(MnO2)-structured coiled electrodes achieve high stretchability (37.5%) without the help of elastomeric substrates, minimizing the size of the supercapacitors. Therefore, high specific capacitances of 34.6 F cm−3, 61.25 mF cm−2, and 2.72 mF cm−1 are achieved for coiled supercapacitors without impairing mechanical stretchability or electrochemical cyclability
Stretchy Electrochemical Harvesters for Binarized Self-Powered Strain Gauge-Based Static Motion Sensors
The human monitoring system has motivated the search for new technology, leading to the development of a self-powered strain sensor. We report on the stretchable and soft stretchy electrochemical harvester (SECH) bilayer for a binarized self-powered strain gauge in dynamic and static motion. The active surface area participating in the electrochemical reaction was enhanced after stretching the SECH in the electrolyte, leading to an increase in the electrochemical double-layer capacitance. A change in the capacitance induced a change in the electrical potential of the bilayer, generating electrical energy. The SECH overcomes several challenges of the previous mechano-electrochemical harvester: The harvester had high elasticity (50%), which satisfied the required strain during human motion. The harvester was highly soft (modulus of 5.8 MPa), 103 times lower than that of the previous harvester. The SECH can be applied to a self-powered strain gauge, capable of measuring stationary deformation and low-speed motion. The SECH created a system to examine the configuration of the human body, as demonstrated by the human monitoring sensor from five independent SECH assembled on the hand. Furthermore, the sensing information was simplified through the binarized signal. It can be used to assess the hand configuration for hand signals and sign language
Shape-engineerable composite fibers and their supercapacitor application
Due to excellent electrical and mechanical properties of carbon nano materials, it is of great interest to fabricate flexible, high conductive, and shape engineered carbon based fibers. As part of these approaches, hollow, twist, ribbon, and other various shapes of carbon based fibers have been researched for various functionality and application. In this paper, we suggest simple and effective method to control the fiber shape. We fabricate the three different shapes of hollow, twisted, and ribbon shaped fibers from wet spun giant graphene oxide (GGO)/single walled-nanotubes (SWNTs)/poly(vinyl alcohol) (PVA) gels. Each shaped fibers exhibit different mechanical properties. The average specific strengthes of the hollow, twist, and ribbon fibers presented here are 126.5, 106.9, and 38.0 MPa while strain are 9.3, 13.5, and 5%, respectively. Especially, the ribbon fiber shows high electrical conductivity (524 ± 64 S cm-1) and areal capacitance (2.38 mF cm-2)
CA-CMT: Coordinate Attention for Optimizing CMT Networks
Vision Transformer (ViT) has been proposed as a new image recognition method in the field of computer vision. ViT applies a Transformer structure with excellent performance in the field of natural language processing to recognize images. Unlike existing Convolutional Neural Network (CNN) models, ViT can achieve State-Of-The-Art (SOTA) image recognition without inputting Inductive Biases into the model, demonstrating that the Transformer is a useful structure in the field of computer vision. However, ViT requires large datasets such as ImageNet-21K and Joint Foto Tree (JFT) for learning. In addition, it takes a lot of time to train. Moreover, there is a problem that location information is lost by inputting images in patch units. To improve such issues, many models are being proposed. In this paper, a new model is proposed by restructuring the Convolutional neural networks Meet vision Transformers (CMT) model by applying Coordinate Attention Block, a CNN model, to improve problems of the Vision Transformer family of models. The proposed model combines Transformer, which has shown excellent performance in Long Range, and CNN, which has shown excellent performance in Local Feature, to achieve higher performance than existing models. We also compared performance of the proposed model with those of existing models with relatively small datasets such as Canadian Institute For Advanced Research-10 (CIFAR-10), Self-Taught Learning-10 (STL-10), and Tiny-ImageNet to facilitate researchers’ access to the evaluation. Despite being restructured from the smallest CMT-Tiny model, the proposed model showed better accuracy than CMT-Tiny, CMT-XS, CMT-S, and CMT-B models with CIFAR-10, STL-10, and Tiny-ImageNet datasets. The proposed model showed an accuracy of 90.21% with the CIFAR-10 dataset, higher than existing CMT models except for the CMT-S model with an accuracy of 90.6%. It had the lowest loss value of 0.3967. The proposed model is expected to be utilized as a backbone in Object Detection and Segmentation fields in the future
Self-Healing Electrode with High Electrical Conductivity and Mechanical Strength for Artificial Electronic Skin
A self-healing electrode is an electrical conductor that can repair internal damage by itself, similar to human skin. Since self-healing electrodes are based on polymers and hydrogels, these components are still limited by low electrical conductivity and mechanical strength. In this study, we designed an electrically conductive, mechanically strong, and printable self-healing electrode using liquid crystal graphene oxide (LCGO) and silver nanowires (AgNWs). The conductive ink was easily prepared by simply mixing LCGO and AgNWs solutions. The ultrathin (3 μm thick) electrode can be printed in various shapes, such as a butterfly, in a freestanding state. The maximum conductivity and strength of the LCGO/AgNW composite were 17 »800 S/cm and 4.2 MPa, respectively; these values are 24 and 4 times higher, respectively, than those of a previously developed self-healing electrode. The LCGO/AgNW composite self-healed internal damage in ambient conditions with moisture and consequently recovered 96.8% electrical conductivity and 95% mechanical toughness compared with the undamaged state. The electrical properties of the composite exhibited metallic tendencies. Therefore, these results suggest that the composite can be used as an artificial electronic skin that detects environmental conditions, such as compression and temperature. This self-healing artificial electronic skin could be applied to human condition monitoring and robotic sensing systems
Pore-controlled carbon nanotube sheet anodes for proton/anion-exchange membrane water electrolyzers
The commercialization of proton/anion-exchange membrane water electrolyzers (PEMWEs/AEMWEs) requires the development of high-performance and durable anodes. Herein, pore-controlled electrodes (C@PCEs) that incorporate carbon nanotube sheets with square pores and catalyst nanoparticles are designed. Ir and NiFe catalysts, which promote the oxygen evolution reaction under acidic and alkaline conditions, respectively, are applied in PEMWEs and AEMWEs. The C@PCEs have higher catalytic activities than the corresponding con-ventional densely packed electrodes (C@DPEs). Additionally, the PEMWEs and AEMWEs with C@PCEs exhibit improved performance with reduced overpotentials compared to those with C@DPEs. This enhancement in performance is ascribed to the pore structure of the C@PCEs, in which the electrocatalyst is well dispersed without agglomeration, thus increasing the electrochemical surface area. In addition, the highly conductive and porous carbon nanotube framework promotes electron and mass transfer. These results demonstrate that the C@PCE design is promising for anodes in both PEMWEs and AEMWEs.11Nsciescopu
Stretchable, weavable coiled carbon nanotube/MnO2/polymer fiber solid-state supercapacitors
Fiber and yarn supercapacitors that are elastomerically deformable without performance loss are sought for such applications as power sources for wearable electronics, micro-devices, and implantable medical devices. Previously reported yarn and fiber supercapacitors are expensive to fabricate, difficult to upscale, or non-stretchable, which limits possible use. The elastomeric electrodes of the present solid-state supercapacitors are made by using giant inserted twist to coil a nylon sewing thread that is helically wrapped with a carbon nanotube sheet, and then electrochemically depositing pseudocapacitive MnO2 nanofibers. These solid-state supercapacitors decrease capacitance by less than 15% when reversibly stretched by 150% in the fiber direction, and largely retain capacitance while being cyclically stretched during charge and discharge. The maximum linear and areal capacitances (based on active materials) and areal energy storage and power densities (based on overall supercapacitor dimensions) are high (5.4 mF/cm, 40.9 mF/cm2, 2.6 μWh/cm2 and 66.9 μW/cm2, respectively), despite the engineered superelasticity of the fiber supercapacitor. Retention of supercapacitor performance during large strain (50%) elastic deformation is demonstrated for supercapacitors incorporated into the wristband of a glove