Piezo2: A Candidate Biomarker for Visceral Hypersensitivity in Irritable Bowel Syndrome?

( Tao Bai ),( Ying Li ),( Jing Xia ),( Yudong Jiang ),( Lei Zhang ),( Huan Wang ),( Wei Qian ),( Jun Song ),( Xiaohua Hou ) 대한소화기기능성질환·운동학회 2017 Journal of Neurogastroenterology and Motility (JNM Vol.23 No.3

Background/Aims Currently, there exists no biomarker for visceral hypersensitivity in irritable bowel syndrome (IBS). Piezo proteins have been proven to play an important role in the mechanical stimulation to induce visceral pain in other tissues and may also be a biomarker candidate. The aim of this study was to test the expressions of Piezo1 and Piezo2 proteins in the intestinal epithelial cells from different intestinal segments and to explore the correlation between Piezo proteins expression and visceral pain threshold. Methods Post-infectious IBS was induced in mice via a Trichinella spiralis infection. Visceral sensitivity was measured with abdominal withdrawal reflex to colorectal distention. Inflammation in the small intestine and colon was scored with H&E staining. Expression location of Piezo proteins was confirmed by immunohistochemistry. Abundance of Piezo proteins were measured with real-time reverse transcriptase polymerase chain reaction. Results Piezo1 and Piezo2 proteins were expressed in the intestinal epithelial cells. The expression levels of Piezo1 and Piezo2 were abundant in the colon than the small intestine (P < 0.001 for Piezo1, P = 0.003 for Piezo2). Expression of Piezo2 in the colon significantly correlated to the visceral sensitivity (r = -0.718, P = 0.001) rather than the mucosal inflammation. Conclusion Piezo2 is a candidate biomarker for visceral hypersensitivity in IBS. (J Neurogastroenterol Motil 2017;23:453-463)

A Mechanosensitive Ion Channel in Merkel that is Optimized for Light-Touch Sensation

( Kyung Chul Shin ),( Sang Woong Park ),( In Hwa Lee ),( Jae Gon Kim ),( Young Min Bae ) 한국감성과학회 2015 추계학술대회 Vol.2015 No.-

Recently, it was shown that Merkel cells and piezo2 ion channels that are expressed in Merkel cells and their Ab afferent fibers play critical roles in the gentle or light-touch somatosensation. However, there is no study reporting the single channel recordings of piezo2 ion currents, hampering the clear understanding of piezo2 characteristics. Here, we investigated whether the Merkel cell carcinoma-13 (MCC-13) cell line express the functional piezo2 ion channels. Further, we also tried to record the single channel current of the piezo2 ion channels in the MCC-13 cells. Under the cell-attached configuration of the patch-clamp technique, application of weak positive pressure ( 5mmHg) markedly activated a non-selective cation current (reversal potential of +3.43 mV, single channel conductance of 30.7 ± 0.7 pS), whereas application of negative pressure (up to 25 mmHg) failed to evoke the currents in MCC-13 cells. In contrast, either positive or negative pressure similarly activated non-selective cation currents in neuro2A cells, which reportedly express mechanosensitive piezo1 ion channel. Immunocytochemistry and Western blotting data showed that the MCC-13 cells express piezo2, whereas neruo2A cells do not. Knock-down of piezo2 by siRNA inhibited both the protein level of piezo2 and the positive pressure-activated ion currents in MCC-13 cells. When expressed in HEK293T cells, the piezo2 ion channel displayed similar positive pressure-specific mechanosensitivity. These results indicate that MCC-13 Merkel cells express mechanosensitive piezo2 ion channels and that the piezo2 channel is low-threshold, positive pressure-sensing ion channel without negative pressure sensitivity. We suggest that piezo2 ion channel is a mechanotransducer optimized for light-touch somatosensation.

커먼레일시스템용 Piezo 인젝터의 노즐내부 연료거동 수치해석

김하늘(Hanul Kim),배장웅(Jangwoong Bae),이진욱(Jinwook Lee),강건용(Kernyong Kang),차경옥(Kyungok Cha) 한국자동차공학회 2004 한국자동차공학회 춘 추계 학술대회 논문집 Vol.- No.-

The PIEZO injector, as 3-generation injector, can be operated from high pressure above 1800bar, It has a higher driven-efficiency than the existing solenoid-injector. Moreover the atomization of diesel fuel, that is injected by high pressure, can be improved in the engine cylinder. A fast response of needle is carried by the characteristics of piezo-electric actuator in PIEZO injector. In this study, a behavior analysis of the internal flow inside nozzle of PIEZO injector performed by the numerical method. The 3-D geometry for numerical model was considered by the central cross-section regarding of one injection hole. Also this geometry classified into the needle lift of 0.1㎜ and 0.2㎜mm with mini. sac volume boundary section, that has sharp edge and round edge, respectively. The computation test was applied with inlet pressure of injector of 400bar and 1300bar and the outlet pressure, that means back-pressure in combustion chamber, of 1 bar and 30bar. Firstly we obtained the basic data under steady state for PIEZO injector before application of moving-mesh. As a result, we found that the round edge appears a high velocity and pressure-drop. Also the obtained research results regarding of the verification of the basic model and simulation of fuel flow inside nozzle of PIEZO injector can be useful applicable the analysis for the moving mesh model.

Effects of Needle Response on Spray Characteristics In High Pressure Injector Driven by Piezo Actuator for Common-Rail Injection System

Lee Jin Wook,Min Kyoung Doug The Korean Society of Mechanical Engineers 2005 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.19 No.5

The common-rail injection systems, as a new diesel injection system for passenger car, have more degrees of freedom in controlling both the injection timing and injection rate with the high pressure. In this study, a piezo-driven injector was applied to a high pressure common-rail type fuel injection system for the control capability of the high pressure injector's needle and firstly examined the piezo-electric characteristics of a piezo-driven injector. Also in order to analyze the effect of injector's needle response driven by different driving method on the injection, we investigated the diesel spray characteristics in a constant volume chamber pressurized by nitrogen gas for two injectors, a solenoid-driven injector and a piezo-driven injector, both equipped with the same injection nozzle with sac type and 5-injection hole. The experimental method for spray visualization was based on back-light photography technique by utilizing a high speed framing camera. The macroscopic spray propagation was geometrically measured and characterized in term of the spray tip penetration, spray cone angle and spray tip speed. For the evaluation of the needle response of the above two injectors, we indirectly estimated the needle's behavior with an accelerometer and injection rate measurement employing Bosch's method was conducted. The experimental results show that the spray tip penetrations of piezo­driven injector were longer, on the whole, than that of the solenoid-driven injector. Besides we found that the piezo-driven injector have a higher injection flow rate by a fast needle response and it was possible to control the injection rate slope in piezo-driven injector by altering the induced current.

고압 연료분사용 피에조 액츄에이터 모델링 및 유압 동특성 해석

김민식(Minsik Kim),이광성(Gwangseog Lee),이중협(Junghyup Lee),이진욱(Jinwook Lee),유호선(Hoseon Yoo),김문헌(Munheon Kim) 한국자동차공학회 2011 한국자동차공학회 부문종합 학술대회 Vol.2011 No.5

In this study, a piezo-driven injector, as a new method driven by piezoelectric energy, has been designed and investigated based on the concept of inverse piezo-electric effect to overcome the major drawbacks of conventional solenoid-driven injector. So it has been applied with a purpose to develop the analysis model of the piezo actuator to predict the dynamics characteristics of the hydraulic component(injector) by using the AMESim code. Aimed at simulating the hydraulic behavior of the piezo-driven injector, the circuit model has been developed and verified by comparison with the experimental results. The effects of an electric control between the solenoid valve and piezo-ceramic stack for injector needle’s driving on the dynamic characteristics were usually investigated. As this research results, we found that the input voltage exerted on piezo stack is the dominant factor and the piezo-driven injector has more degrees of freedom in controlling the fuel injection with the high pressure than a solenoid-driven injector.

피에조 액츄에이터 적용 고압 인젝터의 유압 동특성 해석

이진욱(Jinwook Lee),민경덕(Kyoungdoug Min) 한국자동차공학회 2006 한국 자동차공학회논문집 Vol.14 No.4

In the electro-hydraulic injector for the common rail Diesel fuel injection system, the injection nozle is being opened and closed by movement of a injector’s needle which is balanced by pressure at the nozle seat and at the needle control chamber, at the opposite end of the needle. In this study, the piezo actuator was considered as a prime movers in high pressure Diesel injector. Namely a piezo-driven Diesel injector, as a new method driven by piezoelectric energy, has been applied with a purpose to develop the analysis model of the piezo actuator to predict the dynamics characteristics of the hydraulic component(injector) by using the AMESim code. Aimed at simulating the hydraulic behavior of the piezo-driven injector, the circuit model has been developed and verified by comparison with the experimental results. As this research results, we found that the input voltage exerted on piezo stack is the dominant factor which affects on the initial needle behavior of piezo-driven injector than the hydraulic force generated by the constant injection pressure. Also we know the piezo-driven injector has more degrees of freedom in controlling the injection rate with the high pressure than a solenoid-driven injector.

승용CRDi용 3세대 피에조 인젝터의 내부 유압 모델링 및 수치검증

조인수(Insu Jo),정명철(Myoungchul Jeong),우세종(Saejong Woo),이진욱(Jinwook Lee) 한국자동차공학회 2012 한국자동차공학회 학술대회 및 전시회 Vol.2012 No.11

Performance of DI diesel engine with high fuel injection method is directly related to its emission characteristics and fuel consumption. In this study, new numerical model is designed to analyze of 3rd generation piezo-driven injector. And the injection response characteristics of CRDi injectors between conventional 3-way piezo and 3rd generation piezo-driven injector was investigated by using the AMESim simulation code. From this study, we found the bypass-circuit inside 3rd generation piezo injector can cause the injection response with the biggest difference of each injector. Also it was shown that 3rd generation piezo-driven injector had a faster response and had better control capability than 3-way piezo-driven injector due to hydraulic bypass-circuit.

Piezo-assisted Intracytoplasmic Sperm Injection in Cattle

김세웅,강호인,성지혜,노상호 사단법인 한국동물생명공학회 2010 한국동물생명공학회지 Vol.25 No.2

Intracytoplasmic sperm injection (ICSI) is one of the artificial fertilization methods when only a few sperm are available for insemination, and an important tool for the preservation of genetic materials of endangered animal species, especially the male is infertile. Different from other species such as mice and pigs, the conventional ICSI method which uses spiked pipette for injection (Spike-ICSI) is exhibited low success rates in cattle because the bovine sperm head membrane is hard to break during injection procedure. We chose piezo-assisted ICSI (Piezo-ICSI) for the improvement of the injection procedure including sperm head membrane rupture and efficient puncture of the plasma membrane of the oocytes. In this experiment, we compared the efficacy of the bovine ICSI embryo production between the Piezo-ICSI and Spike-ICSI. The second polar body extrusion, pronuclear formation, cleavage and blastocyst formation were evaluated after implementation of two different ICSI techniques. The Piezo-ICSI tended to show comparably higher rates of the second polar body extrusion (41.7%), the pronuclei formation (42.9%) and the two-cell cleavage (41.4%) than Spike-ICSI does (33.3%, 28.6% and 23.5%, respectively) although there is no statistic significance between two groups. In addition, the blastocysts were only obtained from the Piezo-ICSI group (10.3%). Our finding shows that the Piezo-ICSI may be used as an artificial fertilization method in cattle when in vitro fertilization is not applicable.

Effects of different piezo-acting mechanism on two-stage fuel injection and CI combustion in a CRDi engine

Jin-Su Kim,Juwan Kim,Seokcheol Jeong,Sangilk Han,이진욱 대한기계학회 2016 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.30 No.12

In this study, the effects of two piezo injectors operated by different mechanisms on multi-injection and Compression ignition (CI) combustion were investigated. High-pressure injectors for CI engines are divided into two categories according to the actuator: Solenoid and piezo injectors. It is commonly known that both injectors have a hydraulic circuit for fuel injection; thus, the performance of the injector is highly dependent on not only hydraulic characteristics such as volume of internal chambers and nozzle geometry, but also the actuation mechanism. Specially, the direct needle-Driven piezo injector (DPI) is introduced in this study and compared with the indirectacting Piezo injector (PI) to investigate the injection characteristics and influences on CI combustion performance by using spray visualization, injection rate measurement, and single cylinder diesel engine experiments, as well as numerical simulation for injection rate modeling of DPI. In the spray visualization experiment, a high-speed camera was used to examine spray tip penetration length and spray speed with respect to each injector. Also, in order to investigate injection rate information, which is a significantly dominant factor in combustion characteristics, the Bosch-tube method was adapted under the condition of a back pressure of 4.5 MPa, corresponding to engine motoring pressure. Also, a single-cylinder CRDi (Common-rail direct-injection) engine experiment was carried out to determine the effects of different piezo-acting mechanisms on two-stage fuel injection and CI combustion. From the key results obtained by this study, the direct needle-driven piezo injector has a faster SOI (Start of injection) and EOI (End of injection). In addition, the overall shape of the injection rate of DPI was narrow and the injection had a higher spray speed than that of PI. Also, DPI has a higher heat release rate and peak pressure, as verified by the engine experiment. In particular, it was found that DPI showed the possibility of combustion improvement when applying a pilot injection strategy.

부착형 고분자 압전센서를 이용한 탄성파 검출 연구

김기복,윤동진,권재화,이영섭 한국비파괴검사학회 2004 한국비파괴검사학회지 Vol.24 No.3

스마트 구조물에 적합한 탄성파 검출 센서로서 고분자 압전센서를 이용한 부착형 센서에 대한 연구를 수행하였다. PVDF와 P(VDF-TrFE)에 대하여 센서로서의 특성을 평가하였으며 상용화된 PZT 센서와 비교하였다. 음향임피던스가 서로 다른 여러 가지 재료에 고분자 압전센서를 부착하여 연필심 파괴 시 발생하는 탄성파를 검출하여 분석하였다. 센서의 직경이 증가함에 따라 검출 신호의 최대 진폭값은 증가하였으나 센서의 주파수 검출한계는 감소하는 것으로 나타났다. 시편의 음향임피던스가 감소할수록 검출신호의 최대 진폭값은 증가하였으며 주로 저주파수의 주파수 성분의 신호에 민감한 것으로 분석되었다. 전반적으로 P(VDF-TrFE) 센서가 PVDF 센서보다 감도 면에서 다소 양호한 것으로 나타났다. Patch type piezo-polymer sensors for smart structures were experimented to detect elastic wave. The pencil lead braking test was performed to analyze the characteristics of patch-type piezo-polymer sensors such as polyvinyliden fluoride (PVDF) and polyvinylidene fluoride trifluorethylene (P(VDF-TrFE)) for several test specimens with various elastic wave velocities and acoustical impedances. The characteristics of the patch-type piezo-polymer sensor were compared with the commercial PZT acoustic emission (AE) sensor. The vacuum grease and epoxy resin were used as a couplant for the acoustic impedance matching between the sensor and specimen. The peak amplitude of elastic wave increased as the diameter of piezo-film and acoustical impedance of the specimen increased. The frequency detection range of the piezo-film sensors decreased with increasing diameter of the piezo-film sensor. The P(VDF-TrFE) sensor was more sensitive than the PVDF sensor.