Fully-automatic deep learning-based analysis for determination of the invasiveness of breast cancer cells in an acoustic trap

A single-beam acoustic trapping technique has been shown to be very useful for determining the invasiveness of suspended breast cancer cells in an acoustic trap with a manual calcium analysis method. However, for the rapid translation of the technology into the clinic, the development of an efficient/accurate analytical method is needed. We, therefore, develop a fully-automatic deep learning-based calcium image analysis algorithm for determining the invasiveness of suspended breast cancer cells using a single-beam acoustic trapping system. The algorithm allows to segment cells, find trapped cells, and quantify their calcium changes over time. For better segmentation of calcium fluorescent cells even with vague boundaries, a novel deep learning architecture with multi-scale/multi-channel convolution operations (MM-Net) is devised and constructed by a target inversion training method. The MM-Net outperforms other deep learning models in the cell segmentation. Also, a detection/quantification algorithm is developed and implemented to automatically determine the invasiveness of a trapped cell. For the evaluation of the algorithm, it is applied to quantify the invasiveness of breast cancer cells. The results show that the algorithm offers similar performance to the manual calcium analysis method for determining the invasiveness of cancer cells, suggesting that it may serve as a novel tool to automatically determine the invasiveness of cancer cells with high-efficiency. © 2020 Optical Society of America under the terms of the OSA Open Access Publishing Agreement.1

저자원의 캡슐형 초음파 내시경의 개발과 Coded Excitation

In the treatment of esophageal cancer, a quantitative diagnosis of the cancer stage is essential in providing suitable treatment for patients. However, optical endoscopes which image only the surface of the tumor or computed tomography (CT) scans which damage the body are not suitable diagnostic tools. Alt-hough ultrasound endoscopy is suitable for imaging the cancer’s growth depth into the esophagus, the con-ventional system requires an experienced clinician to insert a large tube into an organ and is highly likely to damage the patient’s esophagus. Recently, to overcome this limitation, various research groups have been studying the capsule type ultrasound endoscopy system, but these are too large for humans to swallow or inappropriate for diagnosis due to low image resolution. To overcome the shortcomings of the capsule type ultrasound endoscope, we developed a small capsule endoscope structure using a reflector and evaluated a signal improvement technique suitable for low voltage. This system minimizes the inter-nal rotation structure through the micro-stepping control of a small step motor, and the performance is compared using coded excitation techniques to optimally obtain a signal at a low voltage. This system has the smallest length compared to existing capsule endoscope modules, and it is possible to secure multiple ultrasound image scan lines through a step motor. Also, through the coded excitation technique, the relative performance of the spatial resolution and signal-to-noise ratio (SNR) of the image according to each tech-nique could be compared in a low-voltage environment. This system showed improvement of low-voltage image performance through miniaturization and signal improvement techniques suitable for insertion into the body of the capsule type ultrasound endoscope system, suggesting that the image improvement through the low-voltage technique can be miniaturized using an appropriate structure. By presenting the advantages and disadvantages of the ultrasound signal improvement technique, suggest the information to enhance imaging depth for developing capsule type ultrasound endoscope.N식도암의 치료에서 정량적인 암의 병기를 진단하는 것은 환자에게 적합한 치료법을 제공하는 데 있어 필수적이다. 기존 암의 표면 영상에 주로 사용되는 광학 내시경이나, 신체에 방사선을 노출하는 CT는 식도 내 암을 깊이 방향으로 영상하는데 있어서 제한이 있다. 반면에 초음파 내시경은 식도 내 암을 깊이 방향으로 영상화하여 암의 병기를 진단하기위해 지금까지 유용하게 사용되어 왔다. 그러나 기존의 초음파 내시경 시스템은 장기 내에 거대한 관을 삽입할 수 있는 숙련된 임상의가 필요할 뿐만 아니라, 삽입 과정 중 환자의 식도 손상을 일으킬 위험성이 있다. 또한 식도까지 물을 채워야 하는 단점이 있어 환자들에게 진단 시 커다란 불편함을 야기시켰다. 최근 이러한 한계를 극복하기 위해 다양한 연구 그룹에서 캡슐형 초음파 내시경 시스템을 연구하고 있으나, 지금까지 개발된 시스템들은 사람이 삼키기에 너무 크거나, 해상도가 낮아 식도 내 암을 진단하는데 한계를 보여 왔다. 따라서, 본 논문에서는 저전력 환경에서 깊은 깊이까지 영상 할 수 있는 캡슐형 초음파 내시경 프로부를 제안하였다. 특히 기존의 단점을 극복하기 위해 반사판을 이용한 소형 캡슐내시경 구조를 개발하고, 소형 스텝 모터의 마이크로스테핑 (micro-stepping) 제어를 통해 내부의 회전 구조를 최소화하였으며, 저전압 환경에서 원하는 깊이까지 고품질의 초음파 영상을 획득하기 위해 여러 Coded Excitation 기법들을 적용하고 각 기법의 성능을 비교하였다. 본 연구에서 개발된 시스템은 기존 캡슐 내시경 모듈들에 비해 크기가 작을 뿐만 아니라, 저 사양 스텝모터를 통해 다수의 초음파 영상 스캔 라인 확보가 가능한 시스템이다. 또한 Coded Excitation 기법을 통해서 저전압 환경에서 공간해상도 (spatial resolution)와 신호대잡음비 (SNR)가 개선된 심부 조직의 초음파 영상을 획득할 수 있다. 특히 저전력 환경에서 초음파 캡슐 내시경에 적용이 가능한 초음파 신호 개선 기법들의 장단점을 제시해주어, 향후 초음파 캡슐 내시경을 개발하는 데 있어서, 영상 깊이 개선을 위한 유용한 정보를 제공한다.MasterdCollectio

Polyol-Mediated Synthesis of V2O5–WO3/TiO2 Catalysts for Low-Temperature Selective Catalytic Reduction with Ammonia

We demonstrated highly efficient selective catalytic reduction catalysts by adopting the polyol process, and the prepared catalysts exhibited a high nitrogen oxide (NOX) removal efficiency of 96% at 250 °C. The V2O5 and WO3 catalyst nanoparticles prepared using the polyol process were smaller (~10 nm) than those prepared using the impregnation method (~20 nm), and the small catalyst size enabled an increase in surface area and catalytic acid sites. The NOX removal efficiencies at temperatures between 200 and 250 °C were enhanced by approximately 30% compared to those of the catalysts prepared using the conventional impregnation method. The NH3-temperature-programmed desorption and H2-temperature-programmed reduction results confirmed that the polyol process produced more surface acid sites at low temperatures and enhanced the redox ability. The in situ Fourier-transform infrared spectra further elucidated the fast absorption of NH3 and its reduction with NO and O2 on the prepared catalyst surfaces. This study provides an effective approach to synthesizing efficient low-temperature SCR catalysts and may contribute to further studies related to other catalytic systems

Hybrid Carbon Supports Composed of Small Reduced Graphene Oxide and Carbon Nanotubes for Durable Oxygen Reduction Catalysts in Proton Exchange Membrane Fuel Cells

We demonstrated highly active and durable hybrid catalysts (HCs) composed of small reduced graphene oxide (srGO) and carbon nanotubes (CNTs) for use as oxygen reduction reaction (ORR) catalysts in proton exchange membrane fuel cells. Pt/srGO and Pt/CNTs were prepared by loading Pt nanoparticles onto srGO and CNTs using a polyol process, and HCs with different Pt/CNT and Pt/srGO ratios were prepared by mechanically mixing the two components. The prepared HCs consisted of Pt/CNTs well dispersed on Pt/srGO, with catalyst HC55, which was prepared using Pt/srGO and Pt/CNTs in a 5:5 ratio, exhibiting excellent oxygen reduction performance and high stability over 1000 cycles of the accelerated durability test (ADT). In particular, after 1000 cycles of the ADT, the normalized electrochemically active surface area of Pt/HC55 decreased by 11.9%, while those of Pt/srGO and Pt/C decreased by 21.2% and 57.6%, respectively. CNTs have strong corrosion resistance because there are fewer defect sites on the surface, and the addition of CNTs in rGO further improved the durability and the electrical conductivity of the catalyst. A detailed analysis of the structural and electrochemical properties of the synthesized catalysts suggested that the synergetic effects of the high specific surface area of srGO and the excellent electrical conductivity of CNTs were responsible for the enhanced efficiency and durability of the catalysts

A Wide-Bandwidth Ultrasound Receiver and On-Chip Ultrasound Transmitter for Ultrasound Capsule Endoscopy

This article presents an ultrasound (US) transceiver IC including a highly power-efficient US receiver (RX) and a high-voltage (HV) US transmitter (TX) for US capsule endoscopy (USCE) systems for the first time. The proposed USCE system employs the developed IC, a single-element piezoelectric transducer (PZT), and a mechanically rotating reflector to obtain 360 transmural scans while traveling through the gastrointestinal (GI) tract. Since the USCE system operates with a tiny battery, power efficiency is greatly important. To reduce power consumption by decreasing the required operating speed of the analog-to-digital converter (ADC), we propose a new RX structure employing synchronized analog envelope detection. It is unlike conventional US RX ICs that necessitate power-hungry high-speed ADCs to acquire the US signal residing at a high center frequency with wide bandwidth. Instead, the proposed work employs an analog envelope detector based on a quadrature demodulation method. As a result, it uses only a single circuit path rather than two (I and Q) paths by using a demodulation carrier whose phase is synchronized with the incoming US signal. A ping-pong noise-shaping (NS) SAR ADC is adopted to improve resolution while maintaining low power consumption. Besides, the TX IC, including an on-chip charge pump, is designed to generate HV pulses to drive the PZT. The prototype IC is fabricated in a 0.18 m bipolar-CMOS-DMOS (BCD) process. The RX consumes 2.3 mW, and the ADC achieves a 53.71 dB SNDR and a 66.45 dB SFDR. The TX generates 25 V pulses with 25 ns pulsewidth. US B-mode images of a water tank and a custom phantom are successfully obtained by using the prototype capsule endoscopy system employing the fabricated IC chip. IEEEFALS