Comparison of ERP Patterns by Suction and Puff Stimulus

( Ji Hye Baek ),( Mi Hyun Choi ),( Ul Ho Jeong ),( Sung Jun Park ),( Seon Young Gim ),( Hyung Sik Kim ),( Soon Cheol Chung ) 한국감성과학회 2015 추계학술대회 Vol.2015 No.-

The aim of this study was to compare event-related potential (ERP) patterns activated somatosensory area (C3) and motor area (FC5) about suction and puff stimulus by applying these stimuli to the fingers. Twelve healthy right-handed men (mean age = 23.1 ± 2.0 years) participated in the study. One session consisted of a Rest Phase (9sec) and a Suction or Puff Phase (3sec). During the Rest Phase, the subjects were instructed to relax and get a ready without any stimulus being applied. During the Suction or Puff Phase, suction or puff stimulus of same intensity (4 psi) was applied to the first joint of the right index finger. Subjects performed 1 session (30 trials) for each suction and puff stimulus. 1 session is repeated twice. After completion of the session, a subjective magnitude test was presented. We extracted the maximum positive amplitude, minimum negative amplitude and relevant latency values from ERP signals from C3 and FC5. Suction and puff stimuli had similar subjective magnitude scores. For C3, the maximum positive latency (suction: 82ms, puff: 100ms) (p = .001) and minimum negative amplitude latency (suction: 167ms, puff: 188ms) (p<.001) was appeared earlier for the suction stimulus than for the puff stimulus. For FC5, the maximum positive latency (suction: 81ms, puff: 90ms) (p = .013) and minimum negative amplitude latency (suction: 168ms, puff: 186ms) (p = .010) was appeared earlier for the suction stimulus than for the puff stimulus. The suction stimulus caused a more sensitivity in the somatosensory area (C3) and motor area (FC5) than did the puff stimulus during suction and puff stimuli of the same intensity.

비용, 인공환기관련폐렴 발생 빈도에 있어서의 개방 기관내 흡인술에 대한 폐쇄 흡인술의 비교

정재우 ( Jae Woo Jung ),최은희 ( Eun Hee Choi ),김진희 ( Jin Hee Kim ),서효경 ( Hyo Kyung Seo ),최지연 ( Ji Yeon Choi ),최재철 ( Jae Cheol Choi ),신종욱 ( Jong Wook Shin ),박인원 ( In Won Park ),최병휘 ( Byoung Whui Choi ),김재열 대한결핵 및 호흡기학회 2008 Tuberculosis and Respiratory Diseases Vol.65 No.3

연구배경: 폐쇄관을 이용한 기관내 흡인은 임상적으로 중한 환자에게 생리적인 이점이 있지만, 병원성 균주에 의한 기관지 내의 집락화가 증가될 수 있다는 보고가 있다. 비용증가는 폐쇄흡인의 또 다른 제한점이다. 본 연구는 폐쇄흡인 및 개방흡인에 따른 병원균주의 집락화와 인공환기관련폐렴의 빈도와 가격효율성을 비교해보고자 시행되었다. 방법: 각각 한 달의 간격을 사이에 두고 내과계 중환자실에 입원한 환자들을 대상으로 다중사용 개방흡인, 단일사용 개방흡인, 다중사용 폐쇄흡인을 순차적으로 시행하였다. 비용, MRSA의 기관지내 집락화, 인공환기폐렴의 발생률을 분석하였다. 결과: 106명의 환자가 연구 대상으로 포함이 되었고, 이 중 20명의 환자가 다중사용 개방흡인을, 42명이 단일사용 개방흡인을, 44명이 다중사용 폐쇄흡인술을 시행받았다. MRSA의 집락화와 인공환기관련폐렴의 빈도는 세 군간에 의미있는 차이를 보이지 않았다. 입원 일당 소모되는 비용은 다중사용 개방흡인이 $10.58, 단일사용 개방흡인이 $28.27, 다중사용 폐쇄흡인의 경우 $23.76인 것으로 나타났다. 결론: 다중사용 폐쇄흡인을 매 48시간마다 교환하는 경우 MRSA 집락화와 인공환기폐렴 발생 빈도는 비슷하였고, 기관내 흡인술에 있어서 비용면에서도 효율적인 방법임을 알 수 있었다. Background: Tracheobronchial suctioning using the closed suctioning system has physiological benefits for critically ill patients. Despite these benefits, there are concerns about increased colonization of tracheobronchial tree by pathogenic organisms. The cost is another hinder to the introduction of closed suction system. The aim of this study was to evaluate the incidence of colonization and ventilator associated pneumonia and the cost-effectiveness of closed suction compared with open suction. Methods: During separated one month period, patients admitted MICU were cared by multiple-use, open suction, single-use, open suction and multiple-use, closed suction method, consecutively. Costs, colonization of tracheobronchial tree by MRSA and the incidence of ventilator-associated pneumonia (VAP) were analyzed. Results: One-hundred and six patients were enrolled. Twenty patients were treated with multiple-use, open suction, while 42 and 44 patients were cared with single-use, open catheter and multiple-use, closed catheter, respectively. Colonization by MRSA and the incidence of VAP were not different among three ways of suctioning. The overall costs per patient per day for suctioning were $10.58 for multiple-use, open suction, $28.27 for single-use, open suction and $23.76 for multiple-use, closed suction. Conclusion: Multiple-use, closed suctioning, when suction catheters were changed every 48 hrs, has the similar incidence of colonization of MRSA and occurrence of VAP and is a cost-efficient way of endotracheal suction.

새만금지역 준설토의 불포화 특성에 대한 실험적 연구

송영석(Song,Young-Suk),유승경(You,Seung-Kyong) 한국토목섬유학회 2011 한국지반신소재학회 논문집 Vol.10 No.3

본 연구에서는 자동 흙-함수특성곡선 시험장치를 이용하여 새만금지역에서 채취한 준설토의 모관흡수력과 체적함수비를 측정하였다. 측정결과를 토대로 Van Genuchten(1980)의 방법을 이용하여 흙-함수특성곡선(SWCC)을 산정하였다. 동일한 유효포 화도에서 건조과정의 모관흡수력은 습윤과정의 모관흡수력보다 크게 나타났다. Lu and Likos(2006)의 방법을 이용하여 모관 흡수력에 따른 흡입응력을 산정하고, 흙-함수특성곡선(SWCC)의 불포화 관련계수를 토대로 흡입응력특성곡선(SSCC)을 예측하였다. 건조과정의 흡입응력은 유효포화도가 증가함에 따라 증가하다가 감소하지만 습윤과정의 흡입응력은 유효포화도가 증가함에 따라 지속적으로 감소한다. 또한 동일한 유효포화도에서 건조과정의 흡입응력은 습윤과정의 흡입응력보다 크게 나타났다. 한편 van Genuchten(1980)의 방법을 이용하여 투수계수함수(HCF)를 예측하였다. 체적함수비가 증가함에 따라 불포화 투수계수는 증가하며, 동일한 모관흡수력에서 건조과정의 투수계수가 습윤과정의 투수계수보다 크게 나타났다. 흙-함수특성곡 선(SWCC)과 흡입응력특성곡선(SSCC)의 산정결과에 의하면 건조 및 습윤과정에서 흡입응력 혹은 모관흡수력에 대한 이력현상이 발생되었다. 이러한 이력현상은 흙입자 사이의 간극수로 인한 잉크병 효과에 의한 것이다. The matric suction and volumetric water content of dredging soils obtained from Saemangeum area were measured by the automated Soil-Water Characteristic Curve (SWCC) apparatus under both drying and wetting conditions. Based on the test result, SWCCs of the dredging soils were estimated by the van Genuchten(1980) model. The matric suction of drying process is larger than that of wetting process at a same effective degree of saturation. The suction stresses for various matirc suctions were estimated using Lu and Likos(2006) model and the Suction Stress Characteristic Curves (SSCC) were predicted using the independent parameter of SWCC. The suction stress of drying path was increased and decreased, while the suction stress of wetting path was continuously decreased with increasing the effective degree. Also, the suction stress of drying path is larger than that of wetting path at a same effective degree of saturation. The Hydraulic Conductivity Function(HCF) was also predicted by the van Genuchten(1980) model. The hydraulic conductivity was increased with increasing the volumetric water content. The hydraulic conductivity of drying path is larger than that of wetting path at a same matric suction. According to the results of SWCCs and SSCCs, the hysteresis phenomenon of suction stress or matric suction during both drying and wetting paths was occurred. The main reason of hysteresis phenomenon is a ink bottle effect of water among soil particles.

Comparison of the effects of open and closed aspiration on end-expiratory lung volume in acute respiratory distress syndrome

Yildirim Süleyman,Saygili Saba Mukaddes,Süneçli Onur,Kirakli Cenk 대한마취통증의학회 2024 Korean Journal of Anesthesiology Vol.77 No.1

Background: Alveoli tend to collapse in patients with acute respiratory distress syndrome (ARDS). Endotracheal aspiration may increase alveolar collapse due to the loss of end-expiratory lung volume (EELV). We aimed to compare the loss of EELV after open and closed suction in patients with ARDS.Methods: This randomized crossover study included 20 patients receiving invasive mechanical ventilation for ARDS. Open and closed suction were applied in a random order. Lung impedance was measured using electric impedance tomography. The change in end-expiratory lung impedance end of suction and at 1, 10, 20, and 30 min after suction, was used to represent the change in EELV. Arterial blood gas analyses and ventilatory parameters such as the plateau pressure (Pplat), driving pressure (Pdrive), and compliance of the respiratory system (CRS) were also recorded.Results: Less volume loss was noted after closed suction than after open suction (mean ΔEELI: −2661 ± 1937 vs. −4415 ± 2363; mean difference: −1753; 95% CI [−2662, −844]; P = 0.001). EELI returned to baseline 10 min after closed suction but did not return to baseline even 30 min after open suction. After closed suction, the Pplat and Pdrive decreased while the CRS increased. Conversely, the Pplat and Pdrive increased while the CRS decreased after open suction.Conclusions: Endotracheal aspiration may result in alveolar collapse due to loss of EELV. Given that closed suction is associated with less volume loss at end-expiration without worsening ventilatory parameters, it should be chosen over open suction in patients with ARDS.

Matric Suction Creep Characteristics of Reticulated Red Clay

Jianzhong Li,Yuanli Yang 대한토목학회 2018 KSCE JOURNAL OF CIVIL ENGINEERING Vol.22 No.10

Matric suction creep is the creep of unsaturated soil caused by loading constant matric suction. Matric suction creep characteristics of reticulated red clay with constant net confing pressure and step-loading matric suction was studied using stress-controlling unsaturated triaxial test apparatus. Test and analysis results show that: (1) with constant net confining pressure, axial and radial strain of the clay caused by creep due to matric suction increases obviously; (2) the increments of axial strain of the clay, caused by creep due to matric suction under constant net confining pressure, is not the same as that of radial strain, and the absolute value of radial strain is bigger than that of axial strain; (3) creep strain produced by the same amount of matric suction decreases as the increasing of the matric suction during step loading creep, which means that matric suction makes the clay hard; and (4) the creep strain-time curves of both axial and radial creep can be simulated very well by exponential decay function, and the parameters of the function are matric suction depend obviously.

Determination of Maximum Penetration Depth of Suction Caissons in Sand

Wu Yuqi,LI Dayong,Zhang Yukun,Chen Fuquan 대한토목학회 2018 KSCE Journal of Civil Engineering Vol.22 No.8

The suction caisson is a large top-closed cylindrical steel structure in diameter, short in length and much thinner in skirt wallthickness. The total resistance of the suction caisson during installation consists of the tip resistance and the skirt wall friction. However, since the thickness of the skirt wall is very small, the skirt wall friction may produce additional vertical stress and shearstress in soil at the skirt tip level, and this additional vertical stress and shear stress will contribute to the increase in the skirt tipresistance. At the same time, seepage induced by suction also causes the tip resistance to reduce significantly. A modified slip-linefield is proposed in this study estimating the tip resistance in terms of the slip-line theory. The expression obtaining the minimumsuction to install the suction caisson is also proposed in terms of the force equilibrium. In addition, the critical suction is determinedbased on the mechanism of sand piping. Thus, the maximum penetration depth of the suction caisson can be reached when the criticalsuction equals the minimum suction. Results from calculations of the minimum suction and the maximum penetration depth havebeen proved to be in a good agreement with the measured data.

A Review on Measurement Techniques and Constitutive Models of Suction in Unsaturated Bentonite Buffer

Jae Owan Lee,Seok Yoon,Geon Young Kim 한국방사성폐기물학회 2019 방사성폐기물학회지 Vol.17 No.3

불포화 벤토나이트 완충재의 수분흡입력은 공학적방벽의 수리-역학적 성능평가 및 설계에 있어 매우 중요한 입력인자이다. 본 연구에서는 문헌에 보고된 불포화 다공성매질의 수분흡입력 측정기술과 구성모델을 분석하고, 고준위폐기물처분장의 벤토나이트 완충재에 적합한 수분흡입력 측정기술과 구성모델을 제안하였다. 문헌 분석결과, 벤토나이트 완충재의 수분흡입력은 일반토질보다 훨씬 높은 값을 가지며, 매트릭수분흡입력과 삼투흡입력을 포함하는 총수분흡입력을 측정하여 사용하였다. 벤토나이트 완충재의 수분흡입력 측정에는 상대습도센서를 이용한 측정방법(RH-Cell, RH-Cell/Sensor)이 적합하였으며, 핵종 붕괴열에 의한 온도변화와 측정 소요시간을 고려했을 때에는 RH-Cell/Sensor 방법이 더 선호되었다. 벤토나이트 완충재의 수분보유모델은 실험을 통해 여러 가지 모델이 제안되었지만, 불포화 완충재의 수리-역학적 성능평가 구성모델로는 대부분 van Genuchten모델이 사용되었다. 벤토나이트 완충재의 수분특성곡선은 벤토나이트의 종류, 건조밀도, 온도, 염도, 측정 시 시료상태와 이력과정에 따라 서로 다른 경향을 보였다. 수분보유모델의 선정 및 모델인자 결정에는 신뢰도 향상을 위해 이러한 인자들의 영향이 고려되어야 한다. Suction of unsaturated bentonite buffers is a very important input parameter for hydro-mechanical performance assessment and design of an engineered barrier system. This study analyzed suction measurement techniques and constitutive models of unsaturated porous media reported in the literature, and suggested suction measurement techniques and constitutive models suitable for bentonite buffer in an HLW repository. The literature review showed the suction of bentonite buffer to be much higher than that of soil, as measured by total suction including matric suction and osmotic suction. The measurement methods (RH-Cell, RH-Cell/Sensor) using a relative humidity sensor were suitable for suction measurement of the bentonite buffer; the RH-Cell /Sensor method was more preferred in consideration of the temperature change due to radioactive decay heat and measurement time. Various water retention models of bentonite buffers have been proposed through experiments, but the van Genuchten model is mainly used as a constitutive model of hydro-mechanical performance assessment of unsaturated buffers. The water characteristic curve of bentonite buffers showed different tendencies according to bentonite type, dry density, temperature, salinity, sample state and hysteresis. Selection of water retention models and determination of model input parameters should consider the effects of these controlling factors so as to improve overall reliability.

불포화 이암풍화토에서의 흡입응력 이력현상

송영석,최진수 한국지반공학회 2012 한국지반공학회논문집 Vol.28 No.3

To investigate the hysteresis of the suction stress in unsaturated weathered mudstone soils (CL), matric suction and volumetric water content were measured in both drying and wetting processes using Automated Soil-Water Characteristics Curve Apparatus. The drying and wetting processes in unsaturated soils were reproduced in the test; the drying process means to load matric suction to spill pore water from the soils, and the wetting process means to unload matric suction to inject pore water into the soils. Based on the measured result, Soil Water Characteristic Curve(SWCC)s were estimated by van Genuchten model (1980). SWCCs have nonlinear relationship between effective degree of saturation and matric suction. The hysteresis in SWCCs between drying and wetting processes occurred. As a result of estimating Suction Stress Characteristic Curve(SSCC) using Lu and Likos model (2006), the suction stress rapidly increased in the low level of matric suction and then increased slightly. Also, the hysteresis in SSCCs between drying and wetting processes occurred. In order to design geo-structures and check its stability considering unsaturated soil mechanics, therefore, it is more reasonable that the SSCC of drying process should be applied in the condition of rainfall infiltration and the SSCC of wetting process in the condition of evaporation or drainage.

Creep Behavior of Unsaturated Reticulate Red Clay Under Matric Suction

Jianzhong Li,Yuanli Yang 대한토목학회 2018 KSCE JOURNAL OF CIVIL ENGINEERING Vol.22 No.2

In order to study unsaturated creep behaviors of reticulate red clay under matric suction, a series of isotropic creep tests with different matric suction level were carried out by using Geotechnical Digital Systems (GDS) unsaturated apparatus. Results indicate that creep strain caused by matric suction increases with the increasing of matric suction level and tends to certain stability over time. Based on the analyses of test results, a creep model for the unsaturated reticulate red clay under matric suction was established to predict the creep strain caused by matric suction. In the model, a new parameter M (matric suction level) was defined as a ratio of the matric suction to the net confining pressure, a hyperbolic function was adopted for the description of the strain-time relationship and an exponential function was employed for the strain-M relationship. Predicted results are in good agreement with the test results shows that the model can reasonably simulate the effects of matric suction on creep properties of unsaturated reticulate red clay.

기관 흡인방법에 따른 외과계 중환자실의 환경오염 수준에 미치는 영향

김 기 숙 대한의료관련감염관리학회 2017 의료관련감염관리 Vol.22 No.2

Background: This study was conducted to evaluate the level of environment contamination before and after endotracheal suctioning using an open or closed suction system in mechanically ventilated patients.Methods: The subjects of this study included 60 patients who were mechanically ventilated from December 2016 to May 2017. Before and after application of an open or closed suction system, blood agar plates (BAPs) were placed 50 cm and 100 cm from the suction port and exposed for 30 minutes. The number of colonies in the BAP culture media was measured.Results: There was a significant difference in the number of colonies on BAPs exposed before and after applying the open suction system at distances of 50 cm (1st; P=0.002, 2nd; P≤0.001) and 100 cm (1st; P=0.040, 2nd; P≤0.001) on both the first day and second day. There was a significant difference in the number of colonies on BAPs exposed before and after applying the closed suction system at the distance of 100 cm (P=0.009) on the first day and at the distance of 50 cm (P=0.043) on the second day. When the open suction system was applied, it was confirmed that the number of colonies was higher after than before suction.Conclusion: The closed suction system is more effective in reducing environmental contamination in hospitals.