• Journal of computational fluids engineering
• /
• v.20 no.2
• /
• pp.88-95
• /
• 2015

Blood pump analysis process includes both mechanical and bio-mechanical aspects. Since a blood pump is a mechanical device, it has to be mechanically efficient. On the other hand, blood pumps function is sensitively related to the blood recirculation; hence, bio-factors such as hemolysis and thrombosis become important. This paper numerically investigates the mechanical and bio-mechanical performances of the Rotaflow in the extracorporeal membrane oxygenation(ECMO), Ventricular Assist Device(VAD), and full-load conditions. The operational conditions are defined as(400[mmHg], 5[L/min.]), (100[mmHg], 3[L/min.]), and (600[mmHg], 10[L/min.]) for ECMO, VAD, and full-load conditions, respectively. The results are presented and analyzed from the mechanical aspect via performance curves, and from bio-mechanical aspect via focusing on hemolytic characteristics. Regions of top and bottom cavities show recirculation in both ECMO and VAD condtions. In addition, Eulerian-based calculation of modified index of hemolysis(MIH) has been investigated. The results demonstrate that the VAD condition has the least risk of hemolysis among the others, while the full-load condition has the highest risk.

• IMMUNE NETWORK
• /
• v.2 no.3
• /
• pp.166-174
• /
• 2002

Background: Human umbilical cord bloods, which could be taken during the delivery are utilized as a source of hematopoietic stem cells. Also in cord blood, there are several kinds of stem cells such as endothelial and mesenchymal stem cells. Methods: We isolated the mesenchymal stem cells from human umbilical cord bloods and confirmed the differentiation of these cells into osteoblast progenitor cells. The mesenchymal stem cells derived from umbilical cord blood have the ability to differentiate into specific tissue cells, which is one of characteristics of stem cells. These cells were originated from the multipolar shaped cells out of adherent cells of the umbilical cord blood mononuclear cell culture. Results: The mesenchymal stem cells expressed cell surface antigen CD13, CD90, CD102, CD105, ${\alpha}$-smooth muscle actin and cytoplasmic antigen vimentine. Having cultrued these cells in bone formation media, we observed the formation of extracellular matrix and the expression of alkaline phosphatase and of mRNA of cbfa-1, ostoecalcin and type I collagen. Conclusion: From these results we concluded that the cells isolated from the umbilical cord blood were mesenchymal stem cells, which we could differentiate into osteoblast when cultured in bone formation media. In short, it is suggested that these cells could be used as a new source of stem cells, which has the probability to alternate the embryonic stem cells.

• Journal of Biomedical Engineering Research
• /
• v.28 no.2
• /
• pp.310-315
• /
• 2007

The axial-flow type blood pump(XVAD) which has been developed in our group consists of mechanical parts (an impeller, a diffuser and a flow straightener) and electrical parts (a motor and a magnetic bearing). The magnetic bearing system fully levitates the impeller to remove mechanical coupling with other parts of the pump with constant gap, which needs non-contact type gap sensing. Conventional gap sensors are too large to be adopted to the implantable axial -flow type blood pump. Thus, in this paper, the compact eddy current type gap sensor system proper for the implantable axial-flow type blood pump was developed and its performance was evaluated in vitro. The developed eddy current type gap sensor system is a transformer type and has a differential probe. Sensor coil(probe) has small dimensions(6 mm diameter, 2 mm thickness) and its optimal inductance was determined as 0.068 mH for the measurement range of $0\sim3mm$. It could be manufactured with 130 turns of the 0.04 mm diameter copper coil. The characteristics of the developed eddy current type gap sensor system was evaluated by in vitro experiment. At experiment, it showed satis(actory performance to apply to the magnetic bearing system of the XVAD. It could measure the gap up to 3mm, but the linearity was decreased at the range of $1.8\sim3.0mm$. Moreover, it showed no difference in different media such as the water and the blood at the temperature range of $35\sim40^{\circ}C$.

• Journal of Sensor Science and Technology
• /
• v.12 no.1
• /
• pp.34-43
• /
• 2003

In this study, we implemented the measurement of pH, $pO_2$, $pCO_2$ of the arterial blood on a portable blood gas analysis system. This system is consist of two parts of hardware and software. The hardware part is divided into a fluidic mechanism and an electronic circuit unit. The system program is composed of operating, washing, correcting, and measuring routines. Both of 1-point and 2-point calibration schemes were used to enhance the accuracy of the measurement. In order to evaluate the performance of the developed system, we measured and performed statistical analysis on the characteristics of the sensing electrode response. As a result, coefficient variation was within 1.12, and maximum error was within 1.298%. We confirmed development possibility of portable blood gas analyzer.

• Journal of Pharmacopuncture
• /
• v.20 no.2
• /
• pp.100-106
• /
• 2017

Objectives: This study aimed to assess a Qi Blood Yin Yang evaluation method systematically and objectively and to identify the correlation between the Qi Blood Yin Yang deficiency pattern (QBYYDP) and facial color. Methods: Thirty-seven participants (17 males, 20 females) were enrolled in this study. Twenty-four (10 males, 14 females) had ages from 40 to over 60, and 13 (7 males and 6 females) were in their twenties. After sufficient rest, facial images were taken with a camera. Based on the results from a questionnaire survey, we divided the participants into five groups: the normal and the Qi-, Blood-, Yin-, and Yang-deficient groups, after which the relationships between the L, 'a', and 'b' values in the Lab color system and the characteristics of the participants in each of the deficient groups were elucidated using a facial color analysis program. Results: The color analysis for Qi-deficient (QD) participants revealed that the L value was fairly decreased in comparison with the normal participants, but the 'a' and 'b' values were almost the same. A comparison between the normal and the Yang-deficient (YaD) groups revealed that the L values were somewhat lower compared to the normal group, but the 'a' and 'b' values were not statistically different. For the Yin-deficient (YiD) group, the L value was slightly lower compared to the normal group, but the 'a' and 'b' values were almost the same and the R values were slightly increased. For the Blood-deficient (BD) group, the L values were slightly increased compared to the normal group, but the 'a' and 'b' values were decreased slightly. Conclusion: This study obtained objective, reliable data for judging the QBYYDP by using facial images and a color analysis program. However, further study with at least 10 or more subjects in each of the deficient groups is necessary to confirm our findings.

• The KSFM Journal of Fluid Machinery
• /
• v.7 no.3 s.24
• /
• pp.14-22
• /
• 2004

Bileaflet mechanical valves have the complications such as hemolysis and thromboembolism, leaflet damage, and leaflet break. These complications are related with the fluid velocity and shear stress characteristics of mechanical heart valves. The first aim of the current study is to introduce fluid-structure interaction method for calculation of unsteady and three-dimensional blood flow through bileaflet valve and leaflet behavior interacted with its flow, and to overcome the shortness of the previous studies, where the leaflet motion has been ignored or simplified, by using FSI method. A finite volume computational fluid dynamics code and a finite element structure dynamics code have been used concurrently to solve the flow and structure equations, respectively, to investigate the interaction between the blood flow and leaflet. As a result, it is observed that the leaflet is closing very slowly at the first stage of processing but it goes too fast at the last stage. And the results noted that the low pressure is formed behind leaflet to make the cavitation because of closing velocity three times faster than opening velocity. Also it is observed some fluttering phenomenon when the leaflet is completely opened. And the rebounce phenomenon due to the sudden pressure change of before and after the leaflet just before closing completely. The some of time-delay is presented between the inversion point of ventricle and aorta pressure and closing point of leaflet. The shear stress is bigger and the time of exposure is longer when the flow rate is maximum. So it is concluded that the distribution of shear stress at complete opening stage has big effect on the blood damage, and that the low-pressure region appeared behind leaflet at complete closing stage has also effect on the blood damage.

• Journal of Microbiology and Biotechnology
• /
• v.15 no.4
• /
• pp.728-733
• /
• 2005

To elucidate the question of whether biofilm formed by the intercellular adhesion (ica) gene cluster has influences on antibiotic resistance in Staphylococcus epidermidis, we compared 124 skin strains with strains isolated from 50 blood cultures that cause septicemic diseases. The results revealed that the blood culture isolates were more resistant to the antibiotics tested than the saprophytic isolates. Moreover, antibiotic multiresistance was more prevalent in the clinical isolates. In the blood culture isolates, $46\%$ of the strains were resistant to three or more antibiotics, whereas only $12\%$ of the saprophytic isolates were resistant to three or more antibiotics. Interestingly, these characteristics were highly correlated with the biofilm formed by the ica gene cluster. In biofilm-producing strains, $84\%$ of the blood culture isolates and $44\%$ of the saprophytic isolates were antibiotic multiresistant, whereas only $22\%=;and\;9\%$, respectively, were antibiotic multiresistant in biofilm-nonproducing strains. Additionally, in the biofilm-producing ica-positive strains, $89\%$ of the blood culture isolates and $57\%$ of the saprophytic isolates were antibiotic multiresistant. However, the rate of the antibiotic multiresistance in the ica-negative strains was very low, thus indicating that the biofim formed by the lea gene cluster in S. epidermidis is an important pathogenic factor in association with the antibiotic multiresistance.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2007.06a
• /
• pp.678-681
• /
• 2007

In this study, an implementation of a system for measuring more accurate blood pressure by non-invasive methods of oscillometric was performed. The system were composed of pressure control, signal measurement, blood pressure signal processing units and wireless sensor network parts. For verify the validity of the system, tests of characteristics evaluations for pressure measurement unit, extraction of characteristic ratios for blood pressure estimation, blood pressure tracking by oscillometric method were performed. A group of five adult male was selected for the clinical test of the implemented system. The results of the oscillometric method in comparison with auscultatory method are that the maximum ratios of PAD of average, systolic and diastolic arterial pressure are 1.38%, 1.63% and 2.97% with SEP of 5.00, 3.72 and 4.34.

• Journal of Chest Surgery
• /
• v.52 no.6
• /
• pp.385-391
• /
• 2019

Background: Preoperative autologous blood donation (PABD) is a conservation strategy for reducing allogenic blood transfusion (ABT) during minimally invasive cardiac surgery (MICS). We aimed to evaluate the effects of PABD on the frequency of ABT and clinical outcomes in patients undergoing MICS. Methods: We enrolled 113 patients (47.8±13.1 years, 50 men) undergoing MICS without preoperative anemia (hemoglobin >11 g/dL) between 2014 and 2017. Of these patients, 69 (the PABD group) donated autologous blood preoperatively and were compared to the non-PABD group (n=44). We analyzed the frequency of perioperative ABT and clinical outcomes. Results: Baseline characteristics did not significantly differ between groups, although preoperative hemoglobin levels were lower in the PABD group. All operations were performed using a minimally invasive approach. Patients' surgical profiles were similar. There were no cases of mortality or significant differences in early postoperative outcomes. During the early postoperative period, hemoglobin levels were higher in the PABD group. No significant difference was found in the frequency of ABT. Conclusion: Although the PABD group had higher postoperative hemoglobin levels, there was no clear clinical benefit in the early postoperative period, despite a great deal of effort and additional cost. Additional PABD in the setting of strict policies for blood conservation was ineffective in reducing ABT for young and relatively healthy patients who underwent MICS.

• Journal of the Korean Dietetic Association
• /
• v.13 no.1
• /
• pp.84-93
• /
• 2007

This study was carried out to see the effect of individualized diet education on the improvement of blood glucose level according to the changes of nutrient intake with the subjects of 25 people. Among 25 people who participated in diabetic education program held in Chilgok-gun public health center, Gyeongbuk, there were 15 diabetic patients(3 males and 12 females) and 10 healthy people(2 males and 8 females) and after the diet education, the results were as follows. As for clinical characteristics, the diabetic group tended to have slightly higher blood pressure than the control group, especially diastolic blood pressure of diabetic group was higher than the control group with a significant level(p<0.05). Blood glucose level measured 2 hours after the meal was higher in the diabetic group than the control group with significant level(p<0.0001). For the clinical characteristic changes before and after the diet education, the blood glucose level in the diabetic group reduced significantly(p<0.01). For the daily diet intake, intake of fat in the diabetic group increased significantly compared to the one before the education(p<0.05). When comparing the ratio of carbohydrate: protein: fat, it was changed from 72.9 : 16.2 : 12.9 before the education to 63.8 : 15.1 : 21.1 after the education. From the above results, it is necessary to perform the diet education which carries out in the health center for diabetic patients with individualized goal by stepwise way rather than as one time try, and by developing the diabetic education media which is appropriate for the patients.