• Journal of Sensor Science and Technology
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• v.31 no.6
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• pp.423-427
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• 2022

A pressure sensor that mimics the sensing ability of human skin has emerged as high-profile technology because it shows remarkable applications in numerous fields such as robotics, human health monitoring, and artificial prosthetics. Whereas recent pressure sensors have achieved high sensitivity similar to that of human skin, they still show limited detection bandwidth. Moreover, once these e-skin are fabricated, their sensitivity and stiffness are fixed; therefore, they can be used for only limited applications. Our study proposes a new adaptive pressure sensor built with uniform gallium microdroplet-elastomer composite. Based on the phase transition of gallium microdroplets, the proposed sensor undergoes mode transformation, enabling it to have a higher sensitivity and wider detection bandwidth compared with those of human skin. In addition, we succeeded in extending a single adaptive pressure sensor to sensor arrays based on its high uniformity, reproducibility, and large-scale manufacturability. Finally, we designed an adaptive e-skin with the sensor array and demonstrated its applications on health monitoring tasks including blood pulse and body weight measurements.

• Korean Journal of Community Nutrition
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• v.4 no.1
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• pp.20-29
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• 1999

This study was done to investigate the nutrient intakes and plasma biochemcial indices in 68 female college students according to their skin types. Nutrient intakes were investigated by quick estimation. The plasma TG and total cholesterol levels were measured by the Spotchem sp-4410. The plasma levels of retinol and $\alpha$-tocopherol were measured by HPLC. In addition, the activities of antioxidant defense enzymes such as plasma glutathione peroxidase(GSH-Px) and glutathione reductase(GHS-Rd) were determined. All data were statistically analyzed by SAS PC package program. The results of this study were as follows : The average age, height, weight, BMI, systolic blood pressure and diastolic blood pressure ofthe subjects were $20.9{\pm}1.9yr, 160.7{\pm}4.3cm, 53.0{\pm}7.1kg, 20.5{\pm}2.4kg/m^2, 105.3{\pm}11.5mmHg and 70.6{\pm}7.7mmHg$, respectively. Ten students(14.7%) had normal skin type, 19 students(27.9%) had dry skin type, 11 students(16.2%) had oily skin type, 17 students(25.0%) had acne and 11 students(16.2%) had mixed skin type. The intakes of energy and fats in oily skin group were significantly higher(p<0.05) than those of the dry skin group, but vitamin C intake in the mixed skin group was significantly higher(p<0.05) than those of the dry skin group, but vitamin C intake in the mixed skin group was significantly lower(p<0.05) than that in other skin types. The intakes of other nutrients were not significantly different among skin types. The analysis of lipids showed that the plasma total-cholesterol level of mixed skin group was significantly lower(p<0.05) than that of the oily skin group, whereas other lipid levels were not significantly different. The other parameters such as retinol, $\alpha$-tocopherol, GSH-Px and GSH-Rd of plasma were not significantly different among skin types. Overall results indicate that dietary intake pattern may influence skin type and thereby some blood biochemical indices can be different by skin types.

• Journal of the Korean Society of Clothing and Textiles
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• v.32 no.10
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• pp.1651-1658
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• 2008

This study was to decided the proper garment pressure level on the human body parts. Six volunteers (female: 30-40years) put on the same types of bands, a brief, and a non-woven gown. Garment pressure was measured in regular order with the elastic band on the human body parts such as the upper arm, the waist, the thigh, and the calf. At the same time, physiological responses such as the skin blood flow rate on 2 fingers, 7 different skin temperatures, rectal temperature, heat rates, and subjective responses about the pressure sensation, thermal sensation, and humidity sensation were measured and inquired. The results were as follows; 1. The thicker subcutaneous fat thickness, the higher the mean garment pressure on pressurizing the upper arm(p<.001). Also the thicker subcutaneous fat thickness. the thicker the upper arm circumference. 2. Heart rates increased pressured the upper arm and decreased pressured the waist, the thigh, and the calf. The higher the garment pressure, the higher heart rates on all body parts were pressured. Especially lean subjects showed higher physiological load than others. 3. On pressurizing the upper arm, heart rates, rectal temperature, and mean skin temperature were higher than without pressured state and pressured other body parts.4. The proper garment pressure levels were decided 30gf/$cm^2$ for fat people, 20gf/$cm^2$ for others on the upper arms and 24gf/$cm^2$ on the calf.

• Journal of Korean Academy of Fundamentals of Nursing
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• v.6 no.2
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• pp.267-276
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• 1999

The purpose of this study was to identify risk factors predictive of alterations in skin integrity during the intraoperative period. The predictive risk factors were studied for intraoperative pressure sores from December 1998 through January 1999. A sample of 220 patients was selected from the operating room schedule of a University Hospital in Pusan. There were two criteria in including patients : the operation lasted longer than 2 hours and the absence of skin break-down according to NPUAP criteria. The data were analized by SPSS/PC, Stepwise multiple logistic regression was used to identify the variables which were predictive of alterations in skin integrity. Of the 220 patients studied, 41 patients (18.6%) developed stage 1 pressure sores in the immediate postoperative period. In relation to skin changes, three independent variables emerged from the stepwise multiple logistic regression as being significant (p<0.05). Factors predictive of pressure sore formation included low serum albumin(p=0.000), prone position while undergoing surgery(p=0.0004), time on the operating table(p=0.0165). Among the intrinsic factors, serum albumin was the most significant causal factor in pressure sores development in the intra-operative period. Pressure and shearing force were the most significant extrinsic factors in pressure sores development. From the results of this study we concluded that the primary nursing goal is the maintenance of the proper patient' position during the intraoperative period. Also imperative for sore prevention is the reduction of surgery time and improving preoperative nutritional status.

• Proceedings of the KSME Conference
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• 2002.08a
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• pp.337-340
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• 2002

The present experimental and numerical investigations are performed for the characteristics of transitional flow in a concentric annulus with a diameter ratio of 0.52, whose outer cylinder is stationary and inner one rotating. The flow field of an annulus has been numerically solved using a finite volume method. The pressure losses and Skin-friction coefficients have been measured for the fully developed flow of water and $0.2{\%}$ aqueous solution of sodium carboximethy1 cellulose (CMC), respectively at inner cylinder rotational speed of $0{\~}600rpm$. The transitional flow has been examined by the measurement of pressure losses to reveal the relation of the Reynolds and Rossby numbers with the skin-friction coefficients. The occurrence of transition has been checked by the gradient changes of pressure losses and skin-friction coefficients with respect to the Reynolds numbers. Consequently the critical(axial-flow) Reynolds number decreases as the rotational speed increases. Thus, the rotation of inner cylinder promotes the early occurrence of transition due to the onset of Taylor vortices.

• Journal of Korean Critical Care Nursing
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• v.11 no.1
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• pp.79-88
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• 2018

Purpose : This study was performed to evaluate the effects of a prolonged a $30^{\circ}$ side-lying position on comfort and skin condition by applying the trunk maintenance repositioning method, which can keep the $30^{\circ}$ side-lying position effective for preventing pressure ulcers. Method : Fifty-four healthy nurses working at a general hospital in Seoul were randomly assigned to an experimental group (n=27) or a control group (n=27) and assumed a position of lying on their right or left side for two hours. The trunk maintenance repositioning method was applied to the experimental group using the pillow made by the researcher, while the original repositioning method was applied to the control group using the regular pillow from the subject hospital. Participants' posture angles, comfort, and skin condition were measured at the time of the intervention, as well as at one and two hours after the intervention. Results : There was no statistically significant difference in position angle, comfort, skin condition change, or sacrum and greater trochanter pressure change between the two groups over time. Conclusion : It is necessary to review the method and frequency of change of position in each hospital. In addition, a proper position changing pillow should be developed in consideration of patients' various body shapes.

• Archives of Plastic Surgery
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• v.46 no.1
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• pp.75-78
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• 2019

It is difficult to differentiate acute skin failure (ASF) from pressure ulcer (PU). ASF is defined as unavoidable injury resulting from hypoperfusion caused by severe dysfunction of another organ system. We describe a case of ASF mistaken as PU that resulted in a legal dispute. A 74-year-old male patient was admitted to our intensive care unit with sepsis due to bacterial pneumonia. Despite the use of air cushions and regular position changes, skin ulcerations occurred over his occiput, back, buttock, elbow, and ankle. After improvement in his general condition, he was transferred to the department of plastic and reconstructive surgery. Debridement was performed immediately, followed by conservative treatment (including a vacuum-assisted closure device) for 6 weeks. The buttock and occiput wounds were treated surgically. Despite complete healing, his caregivers sued the hospital for failing to prevent PU formation. ASF is a pressure-related injury resulting from hemodynamic instability due to organ system failure. Unlike PU, ASF may occur despite the implementation of all appropriate preventive measures. Furthermore, misdiagnosis of ASF as PU can lead to litigation. Therefore, it is critical for the proper diagnosis to be made quickly, and for physicians to explain that ASF occurs despite proper preventative treatment.

• Proceedings of the KSME Conference
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• 2001.06e
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• pp.45-50
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• 2001

This experimental study concerns the characteristics of a transitional flow in a concentric annulus with a diameter ratio of 0.52, whose outer cylinder is stationary and inner one rotating. The pressure losses and skin-friction coefficients have been measured for the fully developed flow of a 0.2 % aqueous solution of sodium carbomethyl cellulose (CMC) at a inner cylinder rotational speed of $0{\sim}600$ rpm. The transitional flow has been examined by the measurement of pressure losses, to reveal the relation of the Reynolds numbers with the skin-friction coefficients, in the laminar and transitional flow regimes. The occurrence of transition has been checked by the gradient change of pressure losses and skin-friction coefficient with respect to the Reynolds numbers. The increasing rate of skin-friction coefficient due to the rotation is uniform for laminar flow regime, whereas it is suddenly reduced for transitional flow regime and, then, it is gradually declined for turbulent flow regime. Consequently, the critical(axial-flow) Reynolds number decrease as the rotational speed increases. Thus, the rotation of inner cylinder promotes the early occurrence of transition due to the onset of taylor vortices.

• Korean Chemical Engineering Research
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• v.44 no.5
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• pp.468-475
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• 2006

For the filtration of super compactible cake, the high filtration pressure can not improve filtration rate. As the high pressure, in this case, decreases the cake porosity adjacent to filter medium and thus forms 'dense skin' which decreases the rate of liquid flow in a great extent. Actually, there was no method to improve filtration rate for the filtration with super compactible cake. We propose the saturation of $CO_2$ gas into the suspension before the filtration operation for improving the filtration rate. The dissolved $CO_2$ gas transforms itself into gas phase in the dense skin through which the pressure changes dramatically. The gas secures its space inside the dense skin, and finally forms the flow passages which improve the filtration rate.

• Journal of Korean Academy of Nursing
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• v.4 no.3
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• pp.93-104
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• 1974

Regardless of a patient's diagnosis, the care of his skin has been a primary concern of nurses throughout the years. Nurses has washed, dried, and rubbed the skin and have changed his position so as to keep the patient's skin in good condition and to protect him from pressure sores. However, we still find many-patients suffering from the pressure sores which may take many mothers or years of treatment and cost a lot to be repaired. In view of expensive cost for treatment of the sores and low ratios of nursing staff per patient for intensive nursing care, prophylaxis of the bed sores with sufficient aids is extremely important both for patients and for nurses. Therefore, the unique purpose of this study was to determine whether sponge is good enough to treat and prevent the pressure sore as compared with gel pad and sheepskin. Sixty patients in the age range of 15 through 45 who were in unconscious status or have difficulty of mobility were chosen between January and March of 1974 at Seoul National University Hospital. They were randomly assigned to each treatment and observed on every 4th day with regard to level of consciousness, status of mobility, moisture or dryness of the bed, general skin condition, intake of nutrition, vital signs and intervals of position change in comparison with the changes of skin over the bony prominences. The study results were reviewed in a statistical method analysis of valiance-to obtain the following findings: 1. There was no significantly different changes of skin over the sanctum or the trochanter in each group using get pad, sheepskin or sponge. It means that we may substitute sponge for expensive gel pad or sheepskin. 2. There was no significant difference among mean changes of patient's skin in relation to sheepskin, gel pad and sponge. 3. There was no significant changes of patient's akin in relation to level of consciousness, status of mobility, intake of nutrition, general skin condition, temperature, blood pressure or interval of position change. 4. There were no meaningful interactions between each treatment and level of consciousness, moisture or dryness of the bed, intake of nutrition, general skin condition, temperature or blood pressure. 5. Sheepskin and gel pad had significantly better influence on patients with limited mobility than on patients with immobility, and sponge on patients with immobility on than patients with limited mobility, 6. Sheepskin and sponge had meaningfully totter influence on patients changing position at below 2-hour interval, gel pad at 2-4-hour interval, sheepskin at 4-6-hour interval, and three of them at above 6-hour interval.