• Title/Summary/Keyword: flow control

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A Numerical Study on the Spray Method for Manufacturing URFC MEA (URFC MEA 제작을 위한 분무법에 관한 수치 해석 연구)

  • SEUNGHWAN KIM;WONHAK SEO;YOUNGJIN SEO;CHULMIN HWANG;SUNGHEE LEE;YOUNGGUAN JUNG
    • Journal of Hydrogen and New Energy
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    • v.35 no.3
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    • pp.345-351
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    • 2024
  • The unitized regenerative fuel cell (URFC) is a method that can reduce costs and increase system simplification by unitizing a fuel cell system and a water electrolysis system. The spray method is suitable as the membrane electrode assembly (MEA) manufacturing method for URFC because it is easy to control the amount of catalyst, the size of the system is small, and economical manufacturing is possible. In this study, a numerical analysis of the effect of solution concentration on the spray method was performed to use it as basic data for the spray method to be used in MEA manufacturing. As result, as the Nafion solution concentration decreases it was found that the spray speed and the mass flow rate and the discrete phase model concentration increases and the spray range widens.

The Effect of the Combination of Ginseng, Tribulus Terrestris, and L-arginine on the Sexual Performance of Men with Erectile Dysfunction: a randomized, double-blind, parallel, and placebo-controlled clinical trial

  • Reza Tahvilian;Mohammad Amin Golesorkhi;Farajollah Parhoudeh;Fatemeh Heydarpour;Hossein Hosseini;Hojjat Baghshahi;Hossein Akbari;Mohammad Reza Memarzadeh;Mehdi Mehran;Hosna Bagheri
    • Journal of Pharmacopuncture
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    • v.27 no.2
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    • pp.82-90
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    • 2024
  • Objectives: Nitric oxide is the most important mediator of penile erection after the onset of sexual excitement. It activates cyclic guanosine monophosphate (cGMP), increasing penile blood flow. Most pharmaceutical medications prevent enzyme phosphodiesterase type 5 (PDE-5) from breaking down cGMP, thus keeping its level high. However, due to the adverse effects of pharmacological therapies, herbal drugs that improve sexual function have gained attention recently. This study aimed to investigate the combined effects of ginseng, Tribulus terrestris, and L-arginine amino acid on the sexual performance of individuals with erectile dysfunction (ED) using the 5-item version of the International Index of Erectile Function (IIEF-5) questionnaire. Methods: Over three months, 98 men with erectile dysfunction were randomly assigned to receive either 500 mg of herbal supplements or placebo pills. Each herbal tablet contained 100 mg of protodioscin, 35 mg of ginsenosides, and 250 mg of L-arginine. Results: The results showed that the changes in the average scores of ILEF-5 within each group before and after the intervention indicated that all parameters related to the improvement of sexual function in patients with erectile dysfunction improved in the herbal treatment group (p < 0.001). The herbal group significantly improved IIEF-5 scores in nondiabetics (p < 0.05). However, there was no significant difference in the changes of IIEF-5 scores between the two intervention and control groups in diabetic patients. Conclusion: In conclusion, ginseng, Tribulus terrestris, and L-arginine have properties that increase energy and strengthen sexual function, making them suitable for patients with sexual disorders.

Numerical simulation and experimental study of non-stationary downburst outflow based on wall jet model

  • Yongli Zhong;Yichen Liu;Hua Zhang;Zhitao Yan;Xinpeng Liu;Jun Luo;Kaihong Bai;Feng Li
    • Wind and Structures
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    • v.38 no.2
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    • pp.129-146
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    • 2024
  • Aiming at the problem of non-stationary wind field simulation of downbursts, a non-stationary down-burst generation system was designed by adding a nozzle and program control valve to the inlet of the original wall jet model. The computational fluid dynamics (CFD) method was used to simulate the downburst. Firstly, the two-dimensional (2D) model was used to study the outflow situation, and the database of working conditions was formed. Then the combined superposition of working conditions was carried out to simulate the full-scale measured downburst. The three-dimensional (3D) large eddy simulation (LES) was used for further verification based on this superposition condition. Finally, the wind tunnel test is used to further verify. The results show that after the valve is opened, the wind ve-locity at low altitude increases rapidly, then stays stable, and the wind velocity at each point fluctuates. The velocity of the 2D model matches the wind velocity trend of the measured downburst well. The 3D model matches the measured downburst flow in terms of wind velocity and pulsation characteris-tics. The time-varying mean wind velocity of the wind tunnel test is in better agreement with the meas-ured time-varying mean wind velocity of the downburst. The power spectrum of fluctuating wind ve-locity at different vertical heights for the test condition also agrees well with the von Karman spectrum, and conforms to the "-5/3" law. The vertical profile of the maximum time-varying average wind veloci-ty obtained from the test shows the basic characteristics of the typical wind profile of the downburst. The effectiveness of the downburst generation system is verified.

Anti-inflammatory Effects of Haepyoijin-tang in Aspergillus Oryzae Protease Induced Respiratory Inflammation Model (Aspergillus oryzae protease 유도 호흡기 염증모델에서 해표이진탕(解表二陳湯)의 항염증 효과)

  • Bo-In Kwon;Joo-Hee Kim
    • Journal of Physiology & Pathology in Korean Medicine
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    • v.38 no.1
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    • pp.16-21
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    • 2024
  • Haepyoijin-tang and its main components have been used for phlegm, cough and dyspnea. Using a respiratory inflammation model, we intend to reveal the anti-inflammatory effect and pharmacological mechanism of Haepyoijin-tang. We induced the respiratory inflammation model by Aspergillus oryzae protease and ovalbumin administration. Female Balb/c mice (8 weeks old) were classified into four groups as follows: saline control group, aspergillus oryzae protease and ovalbumin induced respiratory inflammation group (vehicle), inflammation with Haepyoijin-tang (200 mg/kg) administration group, inflammation with dexamethasone (5 mg/kg) administration group (n=7). To identify the anti-inflammatory effects of Haepyoijin-tang water extracts, we measured the inflammatory cell number in bronchoalveolar lavage fluid (BALF) and total live lung cell number. In addition, we checked eosinophil ratio and number in BALF. And Interleukin (IL)-5 level was also measured in lung cell culture supernatant. To confirm the mechanism of anti-inflammatory effects, we analyzed the activated helper T cell (CD4+CD25+ cell) and Th2 cell (CD4+GATA3+ cell) ratio and number in lung by using flow cytometry. Finally, we attempted to confirm the immune mechanism by measuring the ratio and number of regulatory T cells (CD4+Foxp3+ cell). Haepyoijin-tang extracts treatment diminished inflammatory cell, especially, eosinophil number in BALF and total live lung cell number. Moreover, IL-5 level was reduced in Haepyoijin-tang treated group. Surprisingly, Haepyoijin-tang extracts administration not only decreased the activated helper T cell but also Th2 cell population in lung. Additionally, regulatory T cell population was increased in Haepyoijin-tang administration group. Our findings proved that Haepyoijin-tang extract have anti-inflammatory efficacy by suppressing Th2 cell activation and promoting regulatory T cell population.

Evaluation of the Biodurability of Polyurethane-Covered Stent Using a Flow Phantom

  • Dong Hyun Kim;Sung-Gwon Kang;Jung Ryul Choi;Ju Nam Byun;Young Chul Kim;Young Moo Ahn
    • Korean Journal of Radiology
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    • v.2 no.2
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    • pp.75-79
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    • 2001
  • Objective: To evaluate the biodurability of the covering material in retrievable metallic stents covered with polycarbonate polyurethane. Materials and Methods: Using a peristaltic pump at a constant rate of 1ml/min, bile was recirculated from a reservoir through a long tube containing four stents. Each of these was removed from the system every two weeks and a radial tensile strength test and scanning electron microscopy (SEM) were performed. Each stent, removed at 2, 4, 6 and 8 weeks, was compared with a control stent not exposed to bile juice. Results: Gross examination showed that stents were intact at 2 weeks, but at 4, 6 and 8 weeks cracks were observed. The size of these increased gradually in accordance with the duration of exposure, and at 8 weeks several large holes in the polyurethane membrane were evident. With regard to radial tensile strength, extension and peak load at break were 84.47% and 10.030 N/mm, 54.90% and 6.769 N/mm, 16.55% and 2.452 N/mm, 11.21% and 1.373 N/mm at 0, 2, 4 and 6 weeks, respectively. Scanning electron microscopy at 2 weeks revealed intermittent pitting and cracking, and examination at 4, 6 and 8 weeks showed that the size of these defects was gradually increasing. Conclusion: When the polyurethane membrane was exposed to bile, biodegradation was first observed at week two and increased gradually according to the duration of exposure.

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Effects of Single Leg Ankle Balance Exercise and Neck Stabilization Exercise on Neck Alignment, Muscle and Vascular Thickness in Adults with Forward Head Posture (한발 서기 발목 균형 운동과 목 안정화 운동이 전방 머리 자세를 가진 성인의 목 부위 정렬, 근육 및 혈관두께에 미치는 영향)

  • Sam-Won Yoon;Yun-Hwan Kim;Young-Joo Cha
    • Journal of The Korean Society of Integrative Medicine
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    • v.12 no.3
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    • pp.71-81
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    • 2024
  • Purpose : In this study, we compared the effects of ankle, McKenzie, and cervical stabilization exercises in individuals with a forward head posture. Outcome measures investigated included the neck disability index, craniovertebral angle (CVA), cranial rotation angle (CRA), and thickness of the longus colli muscle (LC) and carotid artery (CA) post-intervention. Methods : The study included 20 individuals with a forward head posture, who were assigned to an experimental group (EG, individuals performed ankle exercises) or control group (CG, individuals performed McKenzie and cervical stabilization exercises). The EG intervention was specifically designed to enhance proprioception in the ankle joint and strengthen the ankle muscles to improve overall stability and function. In contrast, CG interventions aimed to improve neck muscle balance and cervical spine alignment. Paired t-tests were used to analyze intragroup changes and independent t-tests to determine intergroup differences pre-and post-intervention. The significance level for all statistical tests was set at α=.05. Results : We observed significant post-intervention improvements in both groups, specifically, in the CVA, CRA, and LC and CA thickness (p<.05). These results indicate that ankle, McKenzie, and cervical stabilization exercises were useful for neck posture correction, improved muscle balance, and enhanced blood flow to the neck. Conclusion : This study underscores the positive effects of ankle, McKenzie, and cervical stabilization exercises in individuals with a forward head posture. Our study highlights the benefits of these exercises for posture correction and overall neck health and the clinical effectiveness and usefulness of ankle exercises as an important intervention to improve forward head posture.

Correlation between contrast leakage period of procedural rupture and clinical outcomes in endovascular coiling for cerebral aneurysms

  • Sung-Tae Kim;Sung-Chul Jin;Hae Woong Jeong;Jin Wook Baek;Young Gyun Jeong
    • Journal of Cerebrovascular and Endovascular Neurosurgery
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    • v.25 no.4
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    • pp.420-428
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    • 2023
  • Objective: Intraprocedural rupture (IPR) is a fatal complication of endovascular coiling for cerebral aneurysms. We hypothesized that contrast leakage period may be related to poor clinical outcomes. This study aimed to retrospectively evaluate the relationship between clinical outcomes and contrast leakage period. Methods: Data from patients with cerebral aneurysms treated via endovascular coiling between January 2010 and October 2018 were retrospectively assessed. The enrolled patient's demographic data, the aneurysm related findings, endovascular treatment and IPR related findings, rescue treatment, and clinical outcome were analyzed. Results: In total, 2,859 cerebral aneurysms were treated using endovascular coiling during the study period, with IPR occurring in 18 (0.63 %). IPR occurred during initial frame coiling (n=4), coil packing (n=5), stent deployment (n=7), ballooning (n=1), and microcatheter removal after coiling (n=1). Tear sites included the dome (n=14) and neck (n=4). All IPRs were controlled and treated with coil packing, with or without stenting. Flow arrest of the proximal balloon was not observed. Temporary focal neurological deficits developed in two patients (11.1%). At clinical follow-up, 14 patients were classified as modified Rankin Scale (mRS) 0, three as mRS 2, and one as mRS 4. The mean contrast leakage period of IPR was 11.2 min (range: 1-31 min). Cerebral aneurysms with IPR were divided into late (n=9, mean time: 17.11 min) and early (n=9, mean time: 5.22 min) control groups based on the criteria of 10 min of contrast leakage period. No significant between-group differences regarding clinical outcomes were observed after IPR (p=1). Conclusions: In our series, all patients with IPR were controlled with further coil packing or stenting without proximal balloon occlusion within 31 min of contrast leakage. There was no difference in clinical outcomes when the long contrast leakage period group and short contrast leakage period group were compared.

Pro-apoptotic effect of the novel benzylidene derivative MHY695 in human colon cancer cells

  • Gwangbeom Heo;Dongwan Kang;Chaeun Park;Su Jin Kim;Jieun Choo;Yunna Lee;Jin‑Wook Yoo;Yunjin Jung;Jaewon Lee;Nam Deuk Kim;Hae Young Chung;Hyung Ryong Moon;Eunok Im
    • Oncology Letters
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    • v.18 no.3
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    • pp.3256-3264
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    • 2019
  • The induction of apoptosis is a useful strategy in anti-cancer research. Various Moon Hyung Yang (MHY) compounds have been developed as novel anti-cancer drug candidates; in the present study, the pro-apoptotic effects of (Z)-5-(3-ethoxy-4-hydroxybenzylidene)-2-thioxothiazolidin-4-one (MHY695) on HCT116 human colon cancer cells were assessed. MTT assays were performed to investigate the dose-dependent cytotoxic effects of MHY695 on HCT116 cells. Immunofluorescence staining and flow cytometry analyses were performed to identify apoptotic cell death, and western blot analysis was used to investigate the apoptotic-signaling pathways. A mouse xenograft model was also used to determine the effects of MHY695 in vivo. MHY695 decreased the viability of HCT116 cells and induced apoptotic cytotoxicity. The apoptotic mechanisms induced by MHY695 involved the dephosphorylation of Bcl-2-associated agonist of cell death protein following protein kinase B inactivation, induced myeloid leukaemia cell differentiation protein and BH3-interacting domain death agonist truncation, caspase-3 and -9 activation and poly (ADP-ribose) polymerase cleavage. In addition, MHY695 significantly suppressed tumor growth in the mouse xenograft model, compared with the vehicle control. Notably, MHY695 exhibited potent anti-cancer effects in four different types of human colon cancer cell line, including Caco-2, DLD-1, HT-29 and HCT116. Additionally, MHY695 showed reduced cytotoxicity in NCM460, normal colonic epithelial cells. Furthermore, MHY-induced cytotoxicity in colon cancer cells was independent of the tumor suppressor protein p53. Collectively, these observations suggested that MHY695 may be a novel drug for the treatment of colon cancer.

Study on Superconducting Coil Charging Based on Fuel Cell Power for Improving Performance Uniformity of 3-cell Stack (3셀 스택의 성능 균일성 향상을 위한 연료전지 전력 기반 초전도 코일 충전에 관한 연구)

  • YOUNG MIN SEO;HYUN WOO NOH;TAE HYUNG KOO;DONG WOO HA;ROCK KIL KO
    • Journal of Hydrogen and New Energy
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    • v.35 no.4
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    • pp.392-400
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    • 2024
  • In this study, 3-cell stack fuel cell power technology was developed for charging superconducting coil. It was found that the performance of the fuel cell stack increased depending on the number of activation. In addition, the flow rates of hydrogen and air supplied to 3-cell stack was adjusted because of a large difference in membrane electrode assembly (MEA) characteristics depending on its location. As a result, it was confirmed that it was possible to apply current to the superconducting coil from about 15 to 33 A by changing the variable resistance, and it was confirmed that the voltage difference between fuel cell cells could be overcome through sufficient control of fuel supply.

Rivers as Counter-monuments in Manila and Singapore: The Urban Poor's Remembrance in Liwayway Arceo's Canal de la Reina (1972) and Suchen Christine Lim's The River's Song (2013)

  • Dania G. Reyes;Jose Monfred C. Sy
    • SUVANNABHUMI
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    • v.16 no.2
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    • pp.185-211
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    • 2024
  • Southeast Asian cities like Manila, the Philippines, and Singapore have witnessed economic, political, and cultural changes over the years, especially after periods of colonization. States control their urban fabric-that is, its organization, planning, and design of cities-and thus dictate the flow of capital and forces of labor. Urban poor settlements, an offshoot of capital accumulation, are (re)moved around these cities in accordance with governing visions of development. For populations that are forced into changes brought about by urban development, practices of remembering are also controlled by dominant powers. These "monuments" are established in/as spaces to oblige an image of membership into a society ruled by such powers. Nevertheless, alternate sites of remembering counter these monumental spaces. This paper takes an interest in two novels that feature such places. Liwayway Arceo's Canal de la Reina (1972) and Suchen Christine Lim's The River's Song (2013) both figure rivers in Manila and Singapore, respectively. The eponymous river is the central axis of Canal de la Reina, entangled in class conflict and swift urban change in post-Commonwealth Manila. In The River's Song, the famous Singapore River provides a refuge for reminiscing about Singapore before the city-state's independence. Comparing these novels to what Filipino comparatist Ruth Jordana Pison calls fictional "counter-memory," we argue that their rivers remember personal and embodied experiences eliminated from hegemonic accounts of the city. Thus, they function as what we call "counter-monuments" for the urban poor marginalized in the history of the Philippines and Singapore.