Wireless pressure sensor integrated with a 3D printed polymer stent for smart health monitoring

Park, Jongsung,Kim, Ji-Kwan,Kim, Dong-Su,Shanmugasundaram, Arunkumar,Park, Su A,Kang, Sohi,Kim, Sung-Ho,Jeong, Myung Ho,Lee, Dong-Weon Elsevier 2019 Sensors and actuators. B Chemical Vol.280 No.-

<P><B>Abstract</B></P> <P>The primary objective of this study was to deploy a promising wireless pressure sensor system capable of monitoring real-time biological signals in an experimental object. MEMS-based micromachining technology was used to fabricate the proposed SU-8 wireless pressure sensor. The sensor utilizes a capacitor-inductor resonant circuit that can operate the sensor without any external power supply. The variable capacitor in the pressure sensor is designed to change the resonance frequency (130, 183 MHz) in response to applied pressure. The fabricated wireless pressure sensor was integrated into a polymer-based smart stent to minimize the discomfort of medication administration and hospital visits. A 3D bio-printing-based manufacturing technique was employed for the production of a smart polymer stent with complicated shapes. The proposed method is considerably more comfortable than the conventional metal stents fabrication process. The polymer smart stent made of the biocompatible polycaprolactone (PCL) material which can be fully absorbed by the body after a medication period. After integrating the fabricated wireless pressure sensor with the polymer smart stent, various basic experiments such as the working distance of the sensor were performed using a simple experimental setup. The biocompatibility of the proposed polymer stent and the wireless pressure sensor was also successfully confirmed using an experimental animal. The preliminary investigation results indicate that the proposed wireless sensor can be used to obtain necessary information in various parts of the human body as well as the stent.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Fabrication of SU-8 based wireless pressure sensor for battery-less operation. </LI> <LI> Manufacturing of biodegradable polymer stent using 3D printing technique. </LI> <LI> Integration of wireless pressure sensor into polymer stent for real-time blood pressure monitoring. </LI> <LI> Verification of the biocompatibility of smart stent and its operation with experimental animals. </LI> <LI> Continuous measurement of blood pressure change in animals for more than 3 months. </LI> </UL> </P>

표면근전도와 전자각도기를 이용한 자동차 부품 조립작업 위험요인 평가

강동묵,이철호,,신용철,김은아,우지훈,조병만,이수일 大韓産業醫學會 2005 대한직업환경의학회지 Vol.17 No.4

Objectives: As automobile part manufacturing is characterized by high speed and high repetition, observation methods which are usually utilized for static posture are inappropriate to evaluate musculoskeleatal risk factors. This study quantified the risk factors of musculoskeletal disorders on the forearm and suggested exposure limits by estimating the risk factors using surface electromyography (EMG) and electrogoniometer. Methods: Ten percent of the total workers at 3 automobile part manufacturing factories were randomly selected, and 99 male workers were recruited as study subjects. The study was conducted during May 2003 to September 2004. The workers were equipped with electrogoniometers on the wrist and the elbow, surface EMGs on the skin of the flexor digitorum superficialis (FDS) and extensor carpi radialis (ECR) muscles, and the heart beat recorder during work as indicators of joint movement, local muscle tension and physical work load, respectively. Results: After controlling for age, body mass index and job stress, wrist flexion maximum angle, FDS relative activity (RA) and ECR RA were significantly associated with forearm musculoskeletal symptoms. The odds ratios of the forearm were 5.0(95% CI: 1.1-22.7), 14.0(95% CI: 1.5-128.8) and 7.3(95% CI: 1.1-49.4) for wrist flexion maximum angle more than 76˚, FDS RA more than 2.8%, and ECR RA more than 3.5%, respectively. Conclusions: Joint angle and focal muscle activity were associated with forearm musculoskeletal symptoms. To reduce forearm musculoskeletal symptoms among automobile part manufacturers, the wrist flexion angle, and FDS and ECR activity need to be reduced below the guidelines recommended in this study.

복합 페롭스카이트 화합물을 고용한 PZT-PNN계 세라믹스의 전계유기압전변위특성

류지구,김강언,정수태 釜山工業大學校 1994 論文集 Vol.36 No.-

The piezoelectric properties and the electric field dependences of a electric field induced strain constant(D??(E)) are investigated as a variation of PE(PE=PFN, PFW, PZN or PMN) in 0.5[Pb(Ti??Zr??)O₃]-0.45PNN-0.05PE system ceramics. The Curie temperature of samples with PFN or PZN were same, ie, 157[℃] which were higher than those of other samples, and piezoelectric strain constant[d??] of samples with PMN or PZN were more than 320×10??[m/V]. Electric field dependences of D??(E) increased as the coercive field decreased, the order of electric field dependence of D??(E) is PMN > PZN > PFN > PFW. D??(E=0) of samples with PMN or PZN were more than about 520×10??[m/V]. D??(E) of all the samples with excepted PMN increased linearly up to 3[kV/cm]. But D??(E) of sample with PMN rapidly increased at about 2.2[kV/cm], since the sample had the lowest coercive field(3.493[kV/cm]) in the other samples. The sample with PZN showed a higher Curie temperature and D??(E) and a good linearty of D??(E), which are considered to be well suited for a piezoelectric actuator materials.

천연 제올라이트를 이용한 생물학적 처리수의 암모니아성 질소 제거

홍지숙,홍성수,강호 忠南大學校環境問題硏究所 1993 環境硏究 Vol.11 No.-

The ammonium-ion exchange characteristics of domestic natural zeolite was investigated to remove NH4+-N in effluents from biological treatment processes. The effect of water temperature, pH and competitive cationic concentrations on the exchange capacity was examined and the results are as follows. The ammonium-ion exchange capacity was found to be 2.083 meq. NH₄?-N/g-zeolite and not influenced by water temperature, whereas reduced up to 4.2% with the increasing of pH from 7 to 9. The separation factor were increased up to 24% with the water temperature from 25℃ to 55℃. When the competitive cationic concentrations such as K?, Ca²?, and Mg²? increased from 10 to 150mg/L in the di-component systems, the selective ammonium-ion exchange capacity was decreased up to 28%. As with many other studies, the selectivity sequence were K?>Ca²?>Mg²?. The column test has shown that the natural zeolite has a self-sharpening of ion exchange independent of flow rate in the range of 5 to 15 BV/hr. In the column test, the removal efficiences of TOC, COD, PO₄-P and TP from the anaerobic digestor effluent were higher than those from the primary and secondary domestic effluents.

부인과 감염질환 환자에서 Sparfloxacin의 임상적 효과에 대한 연구

변지수,송태복,강형근,김석모 최신의학사 1997 最新醫學 Vol.40 No.7

Pb(Ni₁/₃ Nb₂/₃)O₃ 세라믹스에 있어서 페롭스카이트상의 생성과 유전특성

정수태,류지구,김강언 釜慶大學校 1997 釜慶大學校 論文集 Vol.2 No.2

The reaction sequences of the 3PbO-NiO-Nb?O? [PNN1] and 3PbO-NiNb₂O? [PNN2] system and their dielectric properties were investigated. The pyrochlore phase of PNN1 formed in the order of Pb₃Nb₂O?, Pb?Nb₄O₁?? and Pb₃Nb₄O₁₃ according to increasing of a reaction temperature, and that of PNN2 formed only a Pb₃Nb₄O₁₃. The perovskite phase of Pb(Ni₁/₃Nb₂/₃)O₃[PNN] formed at 920℃ through the diffusion of NiO into the pyrochlore phase of Pb₃Nb₄O₁₃ on both PNN1 and PNN2, but PNN1 showed about 40% of the pyrochlore phase and PNN2 showed about 10% of it.When the samples sintered for 1 hour at 920℃ after calined for 1 hour at 850℃, the PNN1 sample showed yet about 18% of pyrochlore phase, While the PNN2 sample showed 100% of perovskite phase. The PNN2 sample(pyrochlore phase free) had a 1.5 times of maximum dielectric constant and a 0.1 times of dissipation loss(room temperature) compared to the PNN1 sample(pyrochlore phase not free)

縱形 Hall 素子를 이용한 磁氣連算增幅器의 具現

鄭守泰,金康彦,柳志久 釜山工業大學校 1994 論文集 Vol.36 No.-

Vertical Hall devices to dectect a horizontal magnetic field on a chip surface are produced using a bipolar technology. A type B sample is about 1.2 times as sensitive as a type A sample and both samples have good linearity on the Hall voltage in respect to a magnetic fields. A magneto-operational amplifiler(MOP0 is implemented using vertical Hall device, which shows good linearity and switching characteristics. Also we showed that magnetic detections with multifunctions can be accomplished by inserting feedback elements in the MOP.

발치 및 비발치 치료 전후 악궁 폭경의 변화

전지윤,김수정,강승구,박영국 대한치과교정학회 2007 대한치과교정학회지 Vol.37 No.1

일반적으로 네 개의 소구치 발치를 동반한 교정치료는 비발치 치료에 비하여 치열궁 폭경을 더 좁게 만들어, 미소 시 구각 부위에 어두운 구강 내 공간, 소위 buccal corridor를 형성함으로써 비심미적인 결과를 낳는다는 견해가 있다. 한편 발치 치료는 오히려 하악의 견치간 폭경을 증가시키며, 비발치 치료와 비교하여 악궁 폭경의 변화에 있어 유의한 차이를 보이지 않는다는 상반된 연구결과가 존재한다. 이 연구는 발치 치료와 비발치 치료 시 악궁 폭경의 변화를 관찰하여 실제적으로 발치 치료가 미소 시 협측 분절에 미치는 영향을 규명하고자 시행되었다. 경희대학교 치과병원 교정과에서 치료받은 환자 중 전악에 고정식 장치를 사용하여 네 개의 제1소구치 발치 치료를 받은 30명과 비발치로 치료한 30명의 치료 전후 연구 모형을 비교 분석한 결과 악궁 폭경의 변화는 다음과 같다. 네 개의 제1소구치 발치 치료 시 비발치 치료와 비교하여 상악의 견치간 폭경 변화는 유의한 차이가 없었으나, 하악의 견치간 폭경은 유의하게 더 많이 증가하였다. 구치간 폭경 변화는 상악과 하악 치열궁 모두에서 두 군 간에 유의한 차이가 나타났는데, 발치군에서 구치간 폭경이 감소한 반면에 비발치군에서는 구치간 폭경이 증가하였다. 미소 시 노출되는 악궁 폭경은 비발치군보다 발치군에서 더 크게 나타났으며, 이는 치열궁 폭경의 축소가 발치 치료 시 당연히 예상되는 결과가 아님을 시사한다. Objective: This study was performed to investigate the influences of extraction and nonextraction treatment on smile esthetics by measuring dental arch width changes. Methods: Pretreatment and posttreatment study models of 30 first premolar extraction cases and 30 nonextraction cases were randomly selected to determine whether extraction treatment results in narrow dental arches, and a consequent unaesthetic smile. Arch widths were measured from the cusp tips of the canines and the first molars. Posterior arch widths were also measured at a constant arch depth derived by averaging randomly chosen nonextraction models. Results: The intercanine widths increased significantly in the extraction sample, whereas the intermolar widths decreased significantly. The arch width at a standardized arch depth was significantly wider in the extraction subjects. Conclusion: These results elucidate that constriction in arch width is not a materialized consequence of extraction treatment. It leads to postulate that an esthetically compromising effect from narrow dental arches on smile is hardly anticipated with extraction treatment.

국내 다기관에서 조사한 지역사회획득 메티실린내성 황색포도알균의 빈도와 임상적 특성

송진수,최평균,송경호,조재현,김성한,방지환,이창섭,박경화,박경운,신수,최희정,김의석,김동민,이미숙,박완범,김남중,오명돈,김의종,김홍빈,최강원 대한감염학회 2006 감염과 화학요법 Vol.38 No.6

목적 : 최근 전세계적으로 지역사회획득 메티실린내성 황색포도알균(community-associated methicillin-resistant Staphylococcus aureus, CA-MRSA)의 보고가 증가하고 있다. 하지만, 우리나라에서는 CA-MRSA 감염증에 대한 증례보고만 있을 뿐 아직까지 체계적인 연구결과가 없는 실정이다. 저자들은 국내에서 CA-MRSA의 빈도, 감염증의 임상적 양상, 분리된 균주의 항균제내성 양상을 조사하였다. 재료 및 방법 : 2005년 1월부터 2005년 6월까지 7개 병원에서 MRSA가 분리된 환자의 명단을 파악한 후 의무기록지와 건강보험심사평가원의 자료를 검토하였다. 외래나 응급실에서 혹은 입원 후 72시간 이내에 균주가 분리되고 MRSA 획득과 관련된 위험인자가 없는 경우 CA-MRSA로 정의하였으며, 분리된 균주의 임상적 의미에 따라 원인병원체(pathogen), 집락화(colonizer), 미결정(undetermined)으로 분류하였다. Penicillin과 oxacillin을 제외하고 3개 이상의 다른 계열 항균제에 내성이면 다제내성으로 정의하였다. 결과 : 연구기간동안 총 3,251주의 황색포도알균이 분리되었으며, 이 중 MRSA는 1,900주(58.4%)였다. MRSA 가운데 CA-MRSA는 114주(6.0%) 였으며, 이들이 분리된 부위는 귀(62주), 비뇨기계(14주), 피부 및 연부조직(11주), 호흡기계(10주), 혈액(3주) 등이었다. CA-MRSA 균주 가운데 집락균은 22주, 원인병원체는 22주였으며, 나머지 균주에 대해서는 그 임상적 의미를 결정할 수 없었다. 항균제 감수성 검사를 시행한 73균주 중 47주(64.4%)는 다제내성이었다. CA-MRSA 감염증 22예 중 피부 및 연부조직 감염(9예)과 중이염/외이도염(9예)이 가장 흔하였다. 침습적 감염증(invasive infection)은 4명(원발성 균혈증 3예, 감염성 관절염 1예)에서 확인되었지만, CA-MRSA 감염증으로 사망한 환자는 없었다. 결론 : 병원내 감염증에서는 MRSA가 심각한 문제이지만, 아직까지 지역사회 감염증에서 CA-MRSA는 흔하지 않았다. Background : Methicillin-resistant Staphylococcus aureus (MRSA) infection has emerged in patients who do not have the established risk factors. In Korea, little is known about the epidemiology and clinical features of community-associated MRSA (CA-MRSA). Material and Methods : Clinical microbiology laboratory databases of 7 hospitals were reviewed to identify the patients from whom MRSA was isolated during the period of January to July 2005. Only one isolate per patient was enrolled. In order to identify the risk factors of MRSA acquisition, the medical records and the Health Insurance Review Agency databases were reviewed. CA-MRSA was defined as MRSA isolated from patient without established risk factors. We analyzed patient demographics, underlying medical conditions, characteristics of infection, and antimicrobial susceptibility profiles. Results : Of total 3,251 S. aureus isolates, 1900 (58.4%) were MRSAs. Of the MRSA isolates, 114 (6.0%) were CA-MRSA. Of 114 CA-MRSA isolates, 22 (19.3%) were colonizers, 22 (19.3%) were pathogens, and the clinical significance of remaining 70 (61.4%) could not be determined. Median age of the 22 patients with CA-MRSA disease was 47 years. Nine patients had skin and soft tissue infections, 9 ear infections, 3 bacteremia, 1 septic arthritis. Seven patients had underlying medical disease. None died of the CA-MRSA infections. Of the 73 isolates of CA-MRSA, 47 (64.4%) were resistant to more than 3 classes of antibiotics besides β-lactams. Conclusion : Although MRSA is highly prevalent among hospital-associated S. aureus infection, CA-MRSA infections are not common.

한국 비만 여성의 신체 계측에 의한 체지방 추정

심경원,김지연,서희선,이홍수,이상화,강지현 대한비만학회 2002 The Korean journal of obesity Vol.11 No.2

연구배경 : 국내 비만 여성을 대상으로 비용이 적게 들고 단순하면서도 보다 정확하게 체지방률을 추정할 수 있는 체지방률 추정식을 작성함으로써 쉽게 체지방률과 조절해야하는 지방의 양을 판단할 수 있도록 하고자 한다. 방법 : 이대목동병원 비만클리닉을 처음으로 내원한 19세 이상의 성인 여자 607명 중 체질량지수가 25 kg/㎡ 이상인 500명을 연구대상으로 하여 목, 가슴, 허리, 엉덩이, 대퇴, 하퇴, 발목, 상완, 전완, 손목의 10부위의 둘레와 생체전기저항분석법 (bioelectrical impedance analysis, BIA) 방식의 체성분 분석기를 이용하여 체지방률을 측정하였다. 체지방률 추정식을 구하기 위해 BIA에 의한 체지방률을 종속변수로 하고 , 신체 둘레 계측기 및 신장, 체중, 체질량지수, 연령을 독립변수로 하여 단계별 다중회귀분석 (multiple stepwise regression)을 시행하였다. 결과 : 신장과 체중, 연령, 체질량지수 및 신체 둘레 측정치 중 체지방률을 반영하는 지표는 체질량 지수, 전완둘레, 신장, 엉덩이 둘레, 하퇴둘레였고, 이 다섯가지 지표를 이용한 체지방률 추정식은 66.1%의 예측력과 2.86%의 측정 오차를 나타냈다 (R^2=0.661, SEE=2.86). 결론 : 비만한 성인 여성에서 신장과 체중, 연령 및 신체 둘레 계측치를 이용한 본 연구의 추정식은 체지방률(%)을 적은 오차범위로 비교적 정확하게 반영하였다. Background : This study was conducted to develop a regression equation that accurately estimates body fat percentage using relatively easy and inexpensive method in adult obese Korean women. Method : Data were collected among 500 obese Korean women visiting obesity clinic in Ewha woman's university Mokdong hospital, Seoul, Korea. Height, weight, and circumferences at ten body sites (neck, chest, waist, hip, thigh, calf, ankle, arm, forearm, wrist) were measured s well as total body bioelectrical impedance. Results : The full regression equation estimates body fat percentage included six variables : BMI, forearm circumference, height, hip circumference, thigh circumference. This equation accounted for 66.1% of the variance in body weight measured by bioelectrical impedance, and their standard error of estimate was 2.86%. Conclusion : For the obese Korean women in this study, circumference measurements provided a s relatively good estimation of body fat percentage.