• Title/Summary/Keyword: Reducing Pressure Control

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Cardioprotective Effect of Calcium Preconditioning and Its Relation to Protein Kinase C in Isolated Perfused Rabbit Heart (적출관류 토끼 심장에서 칼슘 전처치에 의한 심근보호 효과와 Protein Kinase C와의 관계)

  • 김용한;손동섭;조대윤;양기민;김호덕
    • Journal of Chest Surgery
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    • v.32 no.7
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    • pp.603-612
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    • 1999
  • Background : It has been documented that brief repetitive periods of ischemia and reperfusion (ischemic preconditioning, IP) enhances the recovery of post-ischemic contractile function and reduces infarct size after a longer period of ischemia. Many mechanisms have been proposed to explain this process. Recent studies have suggested that transient increase in the intracellular calcium may have triggered the activation of protein kinase C(PKC); however, there are still many controversies. Accordingly, the author performed the present study to test the hypothesis that preconditioning with high concentration of calcium before sustained subsequent ischemia(calcium preconditioning) mimics IP by PKC activation. Material and Method : The isolated hearts from the New Zealand White rabbits(1.5∼2.0 kg body weight) Method: The isolated hearts from the New Zealand White rabbits(1.5∼2.0 kg body weight) were perfused with Tyrode solution by Langendorff technique. After stabilization of baseline hemodynamics, the hearts were subjected to 45-minute global ischemia followed by a 120-minute reperfusion with IP(IP group, n=13) or without IP(ischemic control, n=10). IP was induced by single episode of 5-minute global ischemia and 10-minute reperfusion. In the Ca2+ preconditioned group, perfusate containing 10(n=10) or 20 mM(n=11) CaCl2 was perfused for 10 minutes after 5-minute ischemia followed by a 45-minute global ischemia and a 120-minute reperfusion. Baseline PKC was measured after 50-minute perfusion without any treatment(n=5). Left ventricular function including developed pressure(LVDP), dP/dt, heart rate, left ventricular end-diastolic pressure(LVEDP) and coronary flow(CF) was measured. Myo car ial cytosolic and membrane PKC activities were measured by 32P-${\gamma}$-ATP incorporation into PKC-specific pepetide. The infarct size was determined using the TTC (tetrazolium salt) staining and planimetry. Data were analyzed using one-way analysis of variance(ANOVA) variance(ANOVA) and Tukey's post-hoc test. Result: IP increased the functional recovery including LVDP, dP/dt and CF(p<0.05) and lowered the ascending range of LVEDP(p<0.05); it also reduced the infarct size from 38% to 20%(p<0.05). In both of the Ca2+ preconditioned group, functional recovery was not significantly different in comparison with the ischemic control, however, the infarct size was reduced to 19∼23%(p<0.05). In comparison with the baseline(7.31 0.31 nmol/g tissue), the activities of the cytosolic PKC tended to decrease in both the IP and Ca2+ preconditioned groups, particularly in the 10 mM Ca2+ preconditioned group(4.19 0.39 nmol/g tissue, p<0.01); the activity of membrane PKC was significantly increased in both IP and 10 mM Ca2+ preconditioned group (p<0.05; 1.84 0.21, 4.00 0.14, and 4.02 0.70 nmol/g tissue in the baseline, IP, and 10 mM Ca2+ preconditioned group, respectively). However, the activity of both PKC fractions were not significantly different between the baseline and the ischemic control. Conclusion: These results indicate that in isolated Langendorff-perfused rabbit heart model, calcium preconditioning with high concentration of calcium does not improve post-ischemic functional recovery. However, it does have an effect of limiting(reducing) the infart size by ischemic preconditioning, and this cardioprotective effect, at least in part, may have resulted from the activation of PKC by calcium which acts as a messenger(or trigger) to activate membrane PKC.

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Recent Progress in Air-Conditioning and Refrigeration Research : A Review of Papers Published in the Korean Journal of Air-Conditioning and Refrigeration Engineering in 2016 (설비공학 분야의 최근 연구 동향 : 2016년 학회지 논문에 대한 종합적 고찰)

  • Lee, Dae-Young;Kim, Sa Ryang;Kim, Hyun-Jung;Kim, Dong-Seon;Park, Jun-Seok;Ihm, Pyeong Chan
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.29 no.6
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    • pp.327-340
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    • 2017
  • This article reviews the papers published in the Korean Journal of Air-Conditioning and Refrigeration Engineering during 2016. It is intended to understand the status of current research in the areas of heating, cooling, ventilation, sanitation, and indoor environments of buildings and plant facilities. Conclusions are as follows. (1) The research works on the thermal and fluid engineering have been reviewed as groups of flow, heat and mass transfer, the reduction of pollutant exhaust gas, cooling and heating, the renewable energy system and the flow around buildings. CFD schemes were used more for all research areas. (2) Research works on heat transfer area have been reviewed in the categories of heat transfer characteristics, pool boiling and condensing heat transfer and industrial heat exchangers. Researches on heat transfer characteristics included the results of the long-term performance variation of the plate-type enthalpy exchange element made of paper, design optimization of an extruded-type cooling structure for reducing the weight of LED street lights, and hot plate welding of thermoplastic elastomer packing. In the area of pool boiling and condensing, the heat transfer characteristics of a finned-tube heat exchanger in a PCM (phase change material) thermal energy storage system, influence of flow boiling heat transfer on fouling phenomenon in nanofluids, and PCM at the simultaneous charging and discharging condition were studied. In the area of industrial heat exchangers, one-dimensional flow network model and porous-media model, and R245fa in a plate-shell heat exchanger were studied. (3) Various studies were published in the categories of refrigeration cycle, alternative refrigeration/energy system, system control. In the refrigeration cycle category, subjects include mobile cold storage heat exchanger, compressor reliability, indirect refrigeration system with $CO_2$ as secondary fluid, heat pump for fuel-cell vehicle, heat recovery from hybrid drier and heat exchangers with two-port and flat tubes. In the alternative refrigeration/energy system category, subjects include membrane module for dehumidification refrigeration, desiccant-assisted low-temperature drying, regenerative evaporative cooler and ejector-assisted multi-stage evaporation. In the system control category, subjects include multi-refrigeration system control, emergency cooling of data center and variable-speed compressor control. (4) In building mechanical system research fields, fifteenth studies were reported for achieving effective design of the mechanical systems, and also for maximizing the energy efficiency of buildings. The topics of the studies included energy performance, HVAC system, ventilation, renewable energies, etc. Proposed designs, performance tests using numerical methods and experiments provide useful information and key data which could be help for improving the energy efficiency of the buildings. (5) The field of architectural environment was mostly focused on indoor environment and building energy. The main researches of indoor environment were related to the analyses of indoor thermal environments controlled by portable cooler, the effects of outdoor wind pressure in airflow at high-rise buildings, window air tightness related to the filling piece shapes, stack effect in core type's office building and the development of a movable drawer-type light shelf with adjustable depth of the reflector. The subjects of building energy were worked on the energy consumption analysis in office building, the prediction of exit air temperature of horizontal geothermal heat exchanger, LS-SVM based modeling of hot water supply load for district heating system, the energy saving effect of ERV system using night purge control method and the effect of strengthened insulation level to the building heating and cooling load.

Effect of Propranolol on Portal Vein Pressure in Patients with Chronic Liver Disease: Evaluation by Perrectal Portal Scintigraphy (만성 간질환에서 Propranolol의 문맥압 감소 효과: 경직장 문맥 신티그라피를 이용한 평가)

  • Rho, Young-Ho;Han, Shin;Kim, Hak-Su;Yoon, Su-Jin;Kim, Yun-Kwon;Kim, So-Yon;Kim, Yeong-Jung;Cho, Min-Koo;Park, Byong-Yik;Lee, Gwon-Jun
    • The Korean Journal of Nuclear Medicine
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    • v.33 no.4
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    • pp.388-397
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    • 1999
  • Purpose: Propranolol is known to decrease portal pressure by reducing blood flow of portal vein. Perrectal portal scintigraphy with Tc-99m pertechnetate has been introduced to evaluate the portal circulation and early diagnosis of liver cirrhosis. We evaluated the effects of propranolol on portal circulation by using per-rectal portal scintigraphy. Materials and Methods: We analyzed the portal hemodynamics by per-rectal portal scintigraphy in 51 patients with liver cirrhosis, 10 chronic hepatitis and 10 normal subjects. 38 patients with cirrhosis underwent per-rectal portal scintigraphy before and after propranolol medication. Perrectal portal scintigraphy was performed after per-rectal administration of 370 MBq of Tc-99m pertechnetate. The shunt index was calculated as the ratio, expressed as a percentage of heart radioactivity to the sum of heart and liver radioactivity during the first 30 seconds. Results: The shunt index in 40 patients with cirrhosis ($59.8{\pm}27.2%$) was significantly higher than that of normal control ($5.0{\pm}1.2%$. p<0.01) and chronic hepatitis ($11.4{\pm}3.5%$, p<0.01). Shunt index was significantly different according to Child's classification and the degree of esophageal varix (p<0.01). After propranolol medication, shunt index was significantly decreased from $59.9{\pm}27.3%$ to $51.3{\pm}15.3%$ (p<0.01) in 38 patients with liver cirrhosis. There was no significant difference of the amount of shunt index reduction after propranolol according to Childs' classification and the degree of esophgageal varix. Conclusion : The effect of propranolol on portal circulation was demonstrated as decreasing shunt index on per-rectal portal scintigraphy in patients with liver cirrhosis. Per-rectal portal scintigraphy may be useful to evaluate the portal circulation and to predict the effect of propranolol in patients with liver cirrhosis.

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A Study on the Torque Characteristics Depending on the Elastic Body Materials of a Hexadecagon Shaped Ultrasonic Motor (탄성체 재질 변화에 따른 16각형 초음파모터의 토크 특성 연구)

  • Cheon, Seong-Kyu;Jeong, Seong-Su;Lee, Byung-Ha;Ha, Yong-Woo;Kim, Myong-Ho;Park, Tae-Gone
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.27 no.5
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    • pp.286-291
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    • 2014
  • In this study, novel ultrasonic rotary motor of hexadecagon shape stator was proposed. Stator of the hexadecagon ultrasonic motor was composed of an elastic ring and ceramics. The elastic ring had sixteen sides and sixteen angular points. Eight ceramics were attached on the outer surface of the eight sides of the ring. When rotor of cylindrical shaft was inserted inside of the ring stator, central lines of the sixteen sides of the stator hold the shaft by the slight pressures(frictions). This slight pressure was a preload of the motor and it could be controlled by radius and thickness of the ring. When two sinusoidal voltages which have 90 degree phase difference were applied to each four ceramics, elliptical displacements of inner surface of the ring were obtained. These elliptical displacements of the inner surface rotated the shaft rotor through the frictions. The proposed hexadecagon ultrasonic motor was designed and analyzed by using the finite element method (FEM), depending on materials of the elastic ring. Based on the FEM results, one model of motor which showed maximum displacement at contact points was chosen and fabricated. And characteristics of the motor were compared with simulated results. When the motor was fabricated with these results, EL20ET0.5CT0.5CW2 model showed 115[rpm] speed about input voltage of 60[Vrms] at 65.6[kHz]. And the maximum torque of 6[gfcm] was obtained. From these results, the hexadecagon shaped ultrasonic motor can be used to actuator for optical device which needs detailed position control. Also it can be used to medical and portable device by reducing size and weight.

Flow Characteristics Evaluation in Reactor Coolant System for Full System Decontamination of Kori-1 Nuclear Power Plant (고리1호기 계통제염을 위한 원자로냉각재내 유동 특성 평가)

  • Kim, Hak Soo;Kim, Cho-Rong
    • Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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    • v.16 no.3
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    • pp.389-396
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    • 2018
  • The Kori-1 Nuclear Power Plant (NPP), WH 2-Loop Pressurized Water Reactor (PWR) operated for approximately 40 years in Korea, was permanently ceased on June 18, 2017. To reduce worker exposure to radiation by reducing the dose rate in the system before starting main decommissioning activities, the permanently ceased Kori-1 NPP will be subjected to full system decontamination. Generally, the range of system decontamination includes Reactor Pressure Vessels (RPV), Pressurizer (PZR), Steam Generators (SG), Chemical & Volume Control System (CVCS), Residual Heat Removal System (RHRS), and Reactor Coolant System (RCS) piping. In order to decontaminate these systems and equipment in an effective manner, it is necessary to evaluate the influence of the flow characteristics in the RCS during the decontamination period. There are various methods of providing circulating flow rate to the system decontamination. In this paper, the flow characteristics in Kori-1 NPP reactor coolant according to RHR pump operation were evaluated. The evaluation results showed that system decontamination using an RHR pump was not effective at decontamination due first to impurities deposited in piping and equipment, and second to the extreme flow unbalance in the RCS caused deposition of impurities.

Biological Monitoring of Workers Exposed to Diisocyanates using Urinary Diamines (소변 중 디아민을 이용한 디이소시아네이트 노출 근로자의 생물학적 모니터링)

  • Lee, Jong Seong;Kim, Boowook;Shin, Jungah;Baek, JinEe;Shin, Jae Hoon;Kim, Ji-hye
    • Journal of Korean Society of Occupational and Environmental Hygiene
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    • v.26 no.2
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    • pp.178-187
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    • 2016
  • Objectives: Diisocyanates are a potent inducer of diseases of the airways, especially asthma. In this study, toluenediamine(TDA) and methylenedianiline(MDA) in urine were evaluated as biomarkers of exposure to tolunenediisocyanate(TDI) and methylenediphenyl diisocyanate(MDI), respectively. Methods: Workers exposed to TDI and MDI, as well as non-occupationally exposed subjects, were studied and pre- and post-shift urine samples were collected from 8 control subjects and 8 workers from a factory which manufactures polyurethane products for reducing noise and vibration in automobiles. Airborne TDI and MDI(n=8) were sampled on solvent-free glass filters impregnated with n-butylamine and detected by liquid chromatography atmospheric pressure ionization tandem mass spectrometry. Urinary TDA and MDA were detected as pentafluoropropionic acid anhydride(PFPA) derivatives by liquid chromatography electrospray ionization tandem mass spectrometry. Results: The median levels of urinary 2,6-TDA(p<0.001), 2,4-TDA(p=0.001), and MDA(p<0.001) of workers in post-shift samples were significantly higher than those of controls. The median levels of urinary 2,6-0TDA($0.63{\mu}g/g$ creatinine vs $0.34{\mu}g/g$ creatinine, p=0.017) and MDA($4.21{\mu}g/g$ creatinine vs $3.18{\mu}g/g$ creatinine, p=0.017) of workers in post-shift samples were significantly higher than those of the pre-shift samples. There were significant correlations between the urinary 2,6-TDA, 2,4-TDA, and MDA of workers in post-shift samples and the airborne 2,6-TDI(rho=0.952, p<0.001), 2,4-TDI(rho=0.833, p=0.001), and MDI(rho=0.952, p<0.001). Conclusions: These urinary diamines, metabolites of diisocyanates, in post-shift samples were useful biomarkers to assess occupational exposure to diisocyanates.

Synthesis of Colloidal Gold and Application of Skin Care Cosmetics (콜로이달 골드 합성 및 스킨케어 화장품 응용)

  • Kim, Dae-Seop;Jeong, Seung-Hyun;Kim, In-Young
    • Journal of the Korean Applied Science and Technology
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    • v.38 no.5
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    • pp.1325-1334
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    • 2021
  • This study reports the development of a manufacturing method of synthesizing colloidal gold using catalysts available for cosmetics and an anti-aging ampoule with skin improvement effects using it. Nano-colloidal gold was synthesized by using ascorbic acid and sodium borohydride as a reducing catalyst in hydrogen tetrachloroaurate tetrahydrate. It was confirmed that the particles became smaller as the mass of the content of ascorbic acid, which is a catalyst, increased. On the other hand, as the mass of sodium borohydride increased, the particle size tended to increase. In order to control the colloidal gold reaction rate, particles having 100 to 500 nm of a particle diameter distribution could be obtained using xanthan gum and hydroxyethylcellulose. The optimal synthesis conditions could be obtained by reacting for 1 to 4 hours at 18℃, a reduced pressure state of 20 to 75 mmHg, a stirring speed of 10~50 rpm. The synthesized colloidal gold had a unique smell of dark pink, pH = 5.5, specific gravity of 1.0032, and viscosity of 80 to 310 cps. As an application of skin care cosmetics, anti-aging ampoule has been developed, and it is expected to be used for various prescriptions and formulations using it.

Evaluation on the Performance of Relief Wells Using Geosynthetics Blanket Length as a Parameter in an Agricultural Reservoir Embankment (농업용 저수지 제방에서 토목섬유 블랭킷의 길이에 따른 감압정의 성능 평가)

  • Ryu, Jeonyong;Kim, Seungwook;Chang, Yongchai
    • Journal of the Korean GEO-environmental Society
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    • v.23 no.6
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    • pp.5-17
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    • 2022
  • The performance of the relief wells installed for the purpose of controlling seepage of the dam embankment is affected by various parameters such as diameter, spacing, penetration rate, permeability coefficient of the ground, thickness of the foundation layer. Therefore, when the relief wells are adopted for the purpose of reducing seepage pressure, these parameters should be sufficiently reviewed to determine the installation specifications of the relief wells. This study evaluated the effect of the length of the geosynthetics blanket on the performance of the relief wells installed in the downstream part of the dam embankment with blankets in the upstream and downstream part of the dam embankment as countermeasure methods to control seepage of the dam embankment. In the relationship between the length of the upstream and downstream blanket and the discharge, the discharge of the relief wells decreases as the length of the upstream blanket increases, and on the other hand, the discharge of the relief wells decreases as the length of the downstream blanket increases. In the upper and lower blanket length-spacing relationship, as the length of the upstream blanket increases, the spacing of the relief wells increases and as the length of the downstream blanket increases, the spacing of the relief wells decreases. Therefore, when installing the relief wells in parallel with the blanket, it was found that increasing the length of the upstream blanket is more efficient than increasing the length of the downstream blanket in order to minimize the discharge of seepage discharge and to ensure economic feasibility by wider installation of the relief wells.

Comparison of Antioxidant and Physiological Properties of Jerusalem Artichoke Leaves with Different Extraction Processes (추출방법에 따른 돼지감자 잎의 항산화 및 생리활성 비교)

  • Kim, Jae-Won;Kim, Jong-Kyoun;Song, In-Seong;Kwon, Eun-Sung;Youn, Kwang-Sup
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.42 no.1
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    • pp.68-75
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    • 2013
  • The physiological properties of water extracts from Jerusalem artichoke (Helianthus tuberosus L.) leaves (JAL) with different extraction processes (stirrer extraction, SE; reflux extraction, RE; autoclave extraction, AE; low temperature high pressure extraction, LTPE) were investigated. The freeze-dried powder yields of SE, RE, AE, and LTPE were 22.33%, 29.88%, 31.65, and 15.74%, respectively. AE showed the highest value of extract yield. The $a^*$ and $b^*$ values were higher in AE compared to other extracts. Total polyphenolics and flavonoids contents in AE was significantly higher than in other extracts. The amount of proanthocyanidin related substances were highest in LTPE (29.36 mg/g), followed by RE (21.57 mg/g), SE (20.35 mg/g), and AE (13.02 mg/g). The electron donating abilities of SE, RE, AE, and LTPE at a concentration of $500{\mu}g/mL$ (w/v) were 76.16%, 39.55%, 25.50%, and 12.59%, respectively. Reducing power for the four different processes was 1.79, 1.60, 1.51, and 1.17, respectively. Additionally the same tendency was observed with electron donating ability and reducing power for ABTS radical and nitrite scavenging abilities. AE and LTPE showed relatively high antioxidant activities. Alpha-glucosidase, xanthine oxidase, and angiotensin I-converting enzyme inhibitory activities of LTPE at a concentration of $500{\mu}g/mL$ (w/v) were somewhat higher than other extracts. Additionally, there was significantly higher or little lower inhibitory activity compared to the control group. In conclusion, we provided experimental evidence that extracts of JAL have potential as functional materials, and component analysis of JAL could be used as new cosmeceuticals. Also, LTPE is the superior method for the enhancement of biological activity.

Dietary Behavior Related to Salty Food Intake of Adults Living in a Rural Area according to Saline Sensitivity (농촌 지역의 중년이후 성인의 염분 민감도에 따른 짠 음식 섭취 관련 식행동)

  • Kim, Mi-Kyoung;Han, Jang-Il;Chung, Young-Jin
    • Journal of Nutrition and Health
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    • v.44 no.6
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    • pp.537-550
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    • 2011
  • This study was conducted to identify behavioral characteristics of salty food intake according to saline sensitivity of adults living in a rural area. Anthropometry and blood pressure were measured and salt intake-related dietary behavior was surveyed by questionnaires through interviews with 402 subjects aged ${\geq}$ 40 years in Chungcheongbuk-Do, Korea. The percentages of overweight and obese among the subjects were 37.8% and 3.8% respectively. Mean blood pressure of the subjects was in the normal range, but the distribution of subjects who were normotensive, high normal, and hypertensive was 48.7%, 17.7%, and 33.6% respectively. Approximately 27% of all subjects habitually consumed salty food, which was the smallest group, followed by 38.1% normal and 35.1% not-salty food. However, 34.6% of the eldest group of ${\geq}$ 65 years consumed salty food. The saline insensitive group showed a higher percentage of irregular meals, overeating, speed-eating, an unbalanced diet, a preference for fried food, and habitual intake of salty foods. These subjects recognized the risk for eating salty food, but they lacked the will to reduce their salty food intake. Compared to spouses and family members, experts such as doctors, nurses, and dieticians were the most influential for reducing the salty food intake of subjects. Saline sensitive group had relatively better control over salty food intake at every meal, eating out, and even when eating salty food that the spouse preferred. The saline sensitive group ate more frequently vegetables and fruits, whereas the saline insensitive group ate more frequently hot spicy foods. In conclusion, the results suggest that it is necessary to establish a social atmosphere toward reducing salt intake at the level of the government and food industry and to set action plans to be available for nutrition education programs to reduce salt intake nationwide.