Monolithic Integration of Ultraslim Flow Sensor and Medical Guidewire by Laser Filament Scanning Sintering for In Vivo Diagnostics of Cardiovascular Diseases.

In this study, an ultraslim thermal flow sensor system integrated onto a 340 µm diameter medical guidewire was developed using a laser filament scanning sintering method for the early diagnosis of cardiovascular diseases. The proposed system is a calorimetric-based micro thermal flow sensor comprising a microheater and two thermistors. Prior to fabrication, the sensor design was optimized through flow simulation, and the patterned sensor was successfully implemented on a thin and curved surface of the medical guidewire using a laser patterning method with Ag nanoparticles. The performance of the ultraslim thermal flow sensor-on-guidewire system (SoW) was evaluated under pulsatile flow by using an artificial heartbeat simulator with differentially induced fluid flow velocities of up to 60 cm/s. The resulting electrical signals generated by the temperature difference between the two thermistors caused by the fluid flow were measured across different velocity ranges. Based on the obtained data, a calibration curve was derived to establish the relationship between the fluid velocity and the sensor output voltage. Furthermore, the SoW was tested on living animals, whereby the measured blood flow velocities were 60-90 cm/s in the left coronary artery of pigs. This research demonstrates the potential of ultraslim microsensors, such as the developed thermal flow sensor system, for various industries, particularly in the medical field.

An AI Safety Monitoring System for Electric Scooters Based on the Number of Riders and Road Types.

Electric scooters are quickly becoming a popular form of mobility in many cities around the world, which has led to a surge in safety incidents. Moreover, electric scooters are not equipped with safety devices for riders, which can lead to serious accidents. In this study, a footrest, data-collection module, and accelerometer module for electric scooters were developed to prevent various accidents caused by the rapid increase in the use of electric scooters. In the experiment, the boarding data of the electric-scooter riders were collected from the footrest and data-collection module. Moreover, the driving data of the electric scooters for different road types were collected with the accelerometer module. We then trained two artificial intelligence (AI) models based on convolutional neural networks (CNNs) for different types of data. When we considered the learning accuracy and mean square error (MSE), which are performance indicators of the ability of the trained AI models to discriminate data, for each AI model, the learning accuracy converged to 100% and the MSE converged to 0. Further, this study is expected to help reduce the accident rate of electric scooters by resolving the causes of frequent accidents involving electric scooters around the world.

ß-Carotene and ß-apo-8'-carotenal contents in processed foods in Korea.

A robust and rapid HPLC method for ß-carotene and ß-apo-8'-carotenal analyses in various processed foods was developed. The analysis method was validated for low-fat, moderate-fat, and high-fat food matrices. The two carotenoids were identified by LC-MS/MS. The detection limits for ß-carotene and ß-apo-8'-carotenal in the three food matrices were 0.08-0.27 µg/g and 0.09-0.18 µg/g, respectively. The inter- and intra-day accuracy and precision were in accordance with the Codex guidelines. The validated method was applied to 57 processed food samples, possibly containing ß-carotene and ß-apo-8'-carotenal, obtained in Korea. The detected ß-carotene and ß-apo-8'-carotenal levels in the samples ranged from not detected (ND) to 6.92 µg/g and ND to 1.63 µg/g, respectively. Chocolate and cheese samples had the highest ß-carotene and ß-apo-8'-carotenal levels, respectively. Notably, several samples with no labeled carotenoid additives contained ß-carotene. Moreover, the developed analytical method was compatible with various processed food matrices. Supplementary Information: The online version contains supplementary material available at 10.1007/s10068-023-01285-2.

Development of an Inertial Sensor Module for Categorizing Anomalous Kicks in Taekwondo and Monitoring the Level of Impact.

In this study, an inertial measurement unit (IMU) sensor module and software algorithm were developed to identify anomalous kicks that should not be given scores in Taekwondo competitions. The IMU sensor module was manufactured with dimensions of 3 cm × 3 cm × 1.5 cm and consists of a high-g sensor for high acceleration measurement, a 9-DOF sensor, and a Wi-Fi module for wireless communication. In the experiment, anomalous kicks and normal kicks were collected by the IMU sensor module, and an AI model was trained. The anomalous kick determination accuracy of the trained AI model was found to be 97.5%. In addition, in order to check whether the strength of a blow can be distinguished using the IMU sensor module, an impact test was performed with a pendulum under the same test conditions as the impact sensor installed in the impact test setup, and the correlation coefficient was 0.99. This study is expected to contribute to improving scoring reliability by suggesting the possibility of discriminating anomalous kicks, which were difficult to judge in Taekwondo competitions, through the analysis of Taekwondo kicks using inertial data and impulses.

Fabrication and Evaluation of a Flexible MEMS-Based Microthermal Flow Sensor.

Based on the results of computational fluid dynamics simulations, this study designed and fabricated a flexible thermal-type micro flow sensor comprising one microheater and two thermistors using a micro-electromechanical system (MEMS) process on a flexible polyimide film. The thermistors were connected to a Wheatstone bridge circuit, and the resistance difference between the thermistors resulting from the generation of a flow was converted into an output voltage signal using LabVIEW software. A mini tube flow test was conducted to demonstrate the sensor's detection of fluid velocity in gas and liquid flows. A good correlation was found between the experimental results and the simulation data. However, the results for the gas and liquid flows differed in that for gas, the output voltage increased with the fluid's velocity and decreased against the liquid's flow velocity. This study's MEMS-based flexible microthermal flow sensor achieved a resolution of 1.1 cm/s in a liquid flow and 0.64 cm/s in a gas flow, respectively, within a fluid flow velocity range of 0-40 cm/s. The sensor is suitable for many applications; however, with some adaptations to its electrical packaging, it will be particularly suitable for detecting biosignals in healthcare applications, including measuring respiration and body fluids.

Improved RRT-Connect Algorithm Based on Triangular Inequality for Robot Path Planning.

This paper proposed a triangular inequality-based rewiring method for the rapidly exploring random tree (RRT)-Connect robot path-planning algorithm that guarantees the planning time compared to the RRT algorithm, to bring it closer to the optimum. To check the proposed algorithm's performance, this paper compared the RRT and RRT-Connect algorithms in various environments through simulation. From these experimental results, the proposed algorithm shows both quicker planning time and shorter path length than the RRT algorithm and shorter path length than the RRT-Connect algorithm with a similar number of samples and planning time.

All-solid-state reduced graphene oxide supercapacitor with large volumetric capacitance and ultralong stability prepared by electrophoretic deposition method.

Portable energy storage devices have gained special attention due to the growing demand for portable electronics. Herein, an all-solid-state supercapacitor is successfully fabricated based on a poly(vinyl alcohol)-H3PO4 (PVA-H3PO4) polymer electrolyte and a reduced graphene oxide (RGO) membrane electrode prepared by electrophoretic deposition (EPD). The RGO electrode fabricated by EPD contains an in-plane layer-by-layer alignment and a moderate porosity that accommodate the electrolyte ions. The all-solid-state RGO supercapacitor is thoroughly tested to give high specific volumetric capacitance (108 F cm(-3)) and excellent energy and power densities (7.5 Wh cm(-3) and 2.9 W cm(-3), respectively). In addition, the all-solid-state RGO supercapacitor exhibits an ultralong lifetime for as long as 180 days (335 000 cycles), which is an ultrahigh cycling capability for a solid-state supercapacitor. The RGO is also tested for being used as a transparent supercapacitor electrode demonstrating its possible use in various transparent optoelectronic devices. Due to the facile scale-up capability of the EPD process and RGO dispersion, the developed all-solid-state supercapacitor is highly applicable to large-area portable energy storage devices.

Electromagnetic interference (EMI) transparent shielding of reduced graphene oxide (RGO) interleaved structure fabricated by electrophoretic deposition.

Here we introduce the electromagnetic shielding effectiveness (SE) of reduced graphene oxide (RGO) sheets interleaved between polyetherimide (PEI) films fabricated by electrophoretic deposition (EPD). Incorporating only 0.66 vol % of RGO, the developed PEI/RGO composite films exhibited an electromagnetic interference shielding effectiveness (EMI SE) at 6.37 dB corresponding to ∼50% shielding of incident waves. Excellent flexibility and optical transparency up to 62% of visible light was demonstrated. It was achieved by placing the RGO sheets in the localized area as a thin film (ca. 20 nm in thickness) between the PEI films (ca. 2 µm) to be an interleaved and alternating structure. This unique interleaved structure without any delamination areas was fabricated by a successive application of cathodic and anodic EPD of both RGO and PEI layers. The EPD fabrication process was ensured by an alternating deposition of the quarternized-PEI drops and RGO, each taking positive and negative charges, respectively, in the water medium. We believe that the developed facile fabrication method of RGO interleaved structure with such low volume fraction has great potential to be used as a transparent EMI shielding material.