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Performance Enhancement of a Pump Impeller Using Optimal Design Method

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Journal of Thermal Science 2017年第2期26卷 119-124页

作者： Seok-Yun jeon Chul-Kyu Kim Sang-Moon Lee Joon-Yong Yoon Choon-Man Jang Korea Institute of Civil Engineering and Building Technology Goyang-siGyeonggi-do10223Korea Dep.of Mechanical Engineering Hanyang UniversityAnsanGyeonggi-do15588Korea

This paper presents the performance evaluation of a regenerative pump to increase its efficiency using optimal design method. Two design parameters which define the shape of the pump impeller, are introduced and analyzed. Pump performance is evaluated by numerical simulation and design of experiments(DOE). To analyze three-dimensional flow field in the pump, general analysis code, CFX, is used in the present work. Shear stress turbulence model is employed to estimate the eddy viscosity. Experimental apparatus with an open-loop facility is set up for measuring the pump performance. Pump performance, efficiency and pressure, obtained from numerical simulation are validated by comparison with the results of experiments. Throughout the shape optimization of the pump impeller at the operating flow condition, the pump efficiency is successfully increased by 3 percent compared to the reference pump. It is noted that the pressure increase of the optimum pump is mainly caused by higher momentum force generated inside blade passage due to the optimal blade shape. Comparisons of pump internal flow on the reference and optimum pump are also investigated and discussed in detail.

关键词： Regenerative Pump Efficiency Impeller Optimal Design Computational Fluid Dynamics

Vitamin D,calcium homeostasis and aging

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Bone Research 2016年第3期4卷 133-139页

作者： Vaishali Veldurthy Ran Wei Leyla Oz Puneet Dhawan Yong Heui jeon Sylvia Christakos Department of Microbiology Biochemistry and Molecular GeneticsRutgersThe State University of New JerseyNew Jersey Medical School

Osteoporosis is characterized by low bone mass and microarchitecture deterioration of bone tissue, leading to enhanced bone fragility and consequent increase in fracture risk. Evidence is accumulating for an important role of calcium deficiency as the process of aging is associated with disturbed calcium balance. Vitamin D is the principal factor that maintains calcium homeostasis. Increasing evidence indicates that the reason for disturbed calcium balance with age is inadequate vitamin D levels in the elderly. In this article, an overview of our current understanding of vitamin D, its metabolism, and mechanisms involved in vitamin D-mediated maintenance of calcium homeostasis is presented. In addition, mechanisms involved in age-related dysregulation of 1,25（OH）2D3 action, recommended daily doses of vitamin D and calcium, and the use of vitamin D analogs for the treatment of osteoporosis （which remains controversial） are reviewed. Elucidation of the molecular pathways of vitamin D action and modifications that occur with aging will be an active area of future research that has the potential to reveal new therapeutic strategies to maintain calcium balance.

关键词： BMD VDR Vitamin D,calcium homeostasis and aging

Korean red ginseng decreases 1-methyl-4-phenylpyridinium-induced mitophagy in SH-SY5Y cells

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Journal of Integrative Medicine 2021年第6期19卷 537-544页

作者： Hyongjun jeon Hee-Young Kim Chang-Hwan Bae Yukyung Lee Sungtae Koo Seungtae Kim Department of Korean Medical Science School of Korean MedicinePusan National UniversityYangsanGyeongsangnam-do 50612Republic of Korea Korean Medicine Research Center for Healthy Aging Pusan National UniversityYangsanGyeongsangnam-do 50612Republic of Korea

Objective:Mitophagy is known to contribute towards progression of Parkinson’s *** red ginseng(KRG)is a widely used medicinal herb in East Asia,and recent studies have reported that KRG prevents 1-methyl-4-phenylpyridinium ion(MPP^(+))-induced cell *** study was undertaken to investigate whether KRG suppresses MPP^(+)-induced apoptosis and ***:SH-SY5 Y cells were incubated with KRG for 24 h,and subsequently exposed to MPP^(+).The MPP^(+)-induced cell death was confirmed with the 3-(4,5-dimethyl-thiazol-2-yl)-2,5-diphenyl tetrazolium bromide assay,and the terminal deoxynucleotidyl transferase-mediated d UTP nick end-labeling *** in the structure and function of mitochondria were confirmed using mitotracker,Mito SOX red mitochondrial superoxide indicator,parkin,and phosphatase and tensin homolog deleted on chromosome ten-induced putative kinase 1(PINK1)immunofluorescent *** blotting was performed to evaluate the expression of apoptosis-related factors in whole cells,including Bax,Bcl-2 and cleaved caspase-3,and mitophagy-related factors in the mitochondrial fraction,including cytochrome c,parkin,PINK1,translocase of the outer membrane 20(TOM20),p62 and Beclin ***:MPP^(+)induced cell death by cytochrome c release and caspase-3 activation;however,this effect was suppressed by KRG’s regulation of the expressions of Bcl-2 and ***,MPP^(+)exposure increased the mitochondrial expressions of parkin,PINK1,Beclin 1 and p62,and decreased TOM20,cytochrome c and Bcl-2 *** MPP^(+)-induced changes in the mitochondrial fraction were attenuated by treatment with ***:KRG effectively prevents MPP^(+)-induced SH-SY5 Y cell death by regulating cytochrome c release from mitochondria and PINK1/parkin-mediated mitophagy,through regulation of the Bcl-2 family.

关键词： Parkinson’s disease Apoptosis Mitophagy 1-Methyl-4-phenylpyridinium Korean red ginseng

Roughness coefficient and its uncertainty in gravel-bed river

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Water Science and Engineering 2010年第2期3卷 217-232页

作者： Ji-Sung KIM Chan-Joo LEE Won KIM Yong-jeon KIM River and Coastal Research Division Korea Institute of Construction Technology

Manning＇s roughness coefficient was estimated for a gravel-bed river reach using field measurements of water level and discharge, and the applicability of various methods used for estimation of the roughness coefficient was evaluated. Results show that the roughness coefficient tends to decrease with increasing discharge and water depth, and over a certain range it appears to remain constant. Comparison of roughness coefficients calculated by field measurement data with those estimated by other methods shows that, although the field-measured values provide approximate roughness coefficients for relatively large discharge, there seems to be rather high uncertainty due to the difference in resultant values. For this reason, uncertainty related to the roughness coefficient was analyzed in terms of change in computed variables. On average, a 20% increase of the roughness coefficient causes a 7% increase in the water depth and an 8% decrease in velocity, but there may be about a 15% increase in the water depth and an equivalent decrease in velocity for certain cross-sections in the study reach. Finally, the validity of estimated roughness coefficient based on field measurements was examined. A 10% error in discharge measurement may lead to more than 10% uncertainty in roughness coefficient estimation, but corresponding uncertainty in computed water depth and velocity is reduced to approximately 5%. Conversely, the necessity for roughness coefficient estimation by field measurement is confirmed.

关键词： roughness coefficient estimation field measurement gravel-bed river uncertainty

Unveiling lymph node metastasis in early gastric cancer

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World Journal of Gastroenterology 2014年第18期20卷 5389-5395页

作者： Nari Shin Tae-Yong jeon Gwang Ha Kim Do Youn Park Department of Pathology Pusan National University Hospital and Pusan National University School of MedicineBusan 602-739South Korea Biomedical Research Institute Pusan National University HospitalBusan 602-739South Korea Departments of Surgery Pusan National University Hospital and Pusan National University School of MedicineBusan 602-739South Korea Departments of Gastroenterology Pusan National University Hospital and Pusan National University School of MedicineBusan 602-739South Korea

With respect to gastric cancer treatment,improvements in endoscopic techniques and novel therapeutic modalities[such as endoscopic mucosal resection(EMR)and endoscopic submucosal dissection(ESD)]have been ***,EMR/ESD procedures are widely accepted treatment modalities for early gastric cancer(EGC).These procedures are most widely accepted in Asia,including in Korea and *** the present era of endoscopic resection,accurate prediction of lymph node(LN)metastasis is a critical component of selecting suitable patients for EMR/***,indications for EMR/ESD are based on large Japanese datasets,which indicate that there is almost no risk of LN metastasis in the subgroup of EGC ***,there is some controversy among investigators regarding the validity of these ***,there are currently no accurate methods to predict LN metastasis in gastric cancer(for example,radiologic methods or methods based on molecular biomarkers).We recommend the use of a 2-step method for the management of early gastric cancer using endoscopic *** first step is the selection of suitable patients for endoscopic resection,based on endoscopic and histopathologic *** endoscopic resection,additional surgical intervention could be determined on the basis of a comprehensive review of the endoscopic mucosal resection/endoscopic submucosal dissection specimen,including lymphovascular tumor emboli,tumor size,histologic type,and depth of ***,evaluation of clinical application data is essential for validating this ***,gastroenterologists,surgeons,and pathologists should closely collaborate and communicate during these decisionmaking processes.

关键词： Early gastric cancer Endoscopic submucosal dissection Lymph node metastasis Biomarker Clinicopathologic features

Standard vs magnifying narrow-band imaging endoscopy for diagnosis of Helicobacter pylori infection and gastric precancerous conditions

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World Journal of Gastroenterology 2021年第18期27卷 2238-2250页

作者： Jun-Hyung Cho Seong Ran jeon So-Young Jin Suyeon Park Digestive Disease Center Soonchunhyang University HospitalSeoul 04401South Korea Department of PathologySoonchunhyang University HospitalSeoul 04401South Korea Department of Pathology Soonchunhyang University HospitalSeoul 04401South Korea Department of Medical Biostatistics Soonchunhyang University HospitalSeoul 04401South Korea

BACKGROUND Advances in endoscopic imaging enable the identification of patients at high risk of gastric ***,there are no comparative data on the utility of standard and magnifying narrow-band imaging(M-NBI)endoscopy for diagnosing Helicobacter pylori(***)infection,gastric atrophy,and intestinal *** To compare the diagnostic performance of standard and M-NBI endoscopy for *** gastritis and precancerous *** In 254 patients,standard endoscopy findings were classified into mosaic-like appearance(type A),diffuse homogenous redness(type B),and irregular redness with groove(type C).Gastric mucosal patterns visualized by M-NBI were classified as regular round pits with polygonal sulci(type Z-1),more dilated and linear pits without sulci(type Z-2),and loss of gastric pits with coiled vessels(type Z-3).RESULTS The diagnostic accuracy of standard and M-NBI endoscopy for *** gastritis was 93.3%and 96.1%,*** gastric precancerous conditions,the accuracy of standard and M-NBI endoscopy was 72.0%vs 72.6%for moderate to severe atrophy,and 61.7%vs.61.1%for intestinal metaplasia in the corpus,*** to type A and Z-1,types B+C and Z-2+Z-3 were significantly associated with moderate to severe atrophy[odds ratio(OR)=5.56 and 8.67]and serum pepsinogen I/II ratio of≤3(OR=4.48 and 5.69).CONCLUSION Close observation of the gastric mucosa by standard and M-NBI endoscopy is useful for the diagnosis of *** gastritis and precancerous conditions.

关键词： Endoscopy Magnifying narrow-band imaging Helicobacter pylori Gastric atrophy Intestinal metaplasia Pepsinogen

Superior laryngeal nerve block for treatment of throat pain and cough following laryngeal herpes zoster:A case report

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World Journal of Clinical Cases 2023年第18期11卷 4433-4437页

作者： Jinyoung Oh Youngje Park jeongkyu Choi Younghoon jeon Department of Anesthesiology and Pain Medicine School of MedicineKyungpook National UniversityDaegu 41944South Korea Department of Anesthesiology and Pain Medicine Kyungpook National University HospitalDaegu 41944South Korea Department of Anesthesiology and Pain Medicine School of DentistryKyungpook National UniversityDaegu 41944South Korea

BACKGROUND Herpes zoster is caused by reactivation of latent varicella-zoster virus infection within the sensory nerve ganglion of the spinal or cranial *** herpes zoster is rare and involves superior laryngeal nerve,which leads to several complications such as throat pain,and *** SUMMARY Patient concerns:A 52-year old woman presented with a 70 d history of throat pain and a 67 d history of non-productive *** days after onset of pain,she was diagnosed with laryngeal herpes *** nasolaryngoscopy revealed multiple white ulcerated lesions on the left hemi epiglottis and the left supraglottic *** was prescribed with 750 mg famciclovir a day for 7 d,and 150 mg pregabalin,100 mg tramadol and 10 mg nortriptyline a day for 67 ***,despite of these medications,she complained of pain and persistent ***,superior laryngeal nerve block under ultrasound guidance was *** days after the intervention,the throat pain and cough *** patient remained symptom-free at 3 mo *** A superior laryngeal nerve block can be an effective option for treatment of pain and cough following laryngeal herpes zoster.

关键词： Cough Herpes zoster Larynx Neuralgia Pain Superior laryngeal nerve Case report

Endoscopic radial incision and cutting technique for treatment-naive stricture of colorectal anastomosis:Two case reports

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World Journal of Gastrointestinal Surgery 2020年第11期12卷 460-467页

作者： Taek-Gu Lee Soon Man Yoon Sang-jeon Lee Department of Surgery Chungbuk National University HospitalChungbuk National University College of MedicineCheongju-si 28644Chungcheongbuk-doSouth Korea Department of Internal medicine Chungbuk National University HospitalChungbuk National University College of MedicineCheongju-si 28644Chungcheongbuk-doSouth Korea

BACKGROUND Anastomotic stenosis(AS)after colorectal surgery was treated with balloon dilation,endoscopic procedure or *** endoscopic procedures including dilation,electrocautery incision,or radial incision and cutting(RIC)were preferred because of lower complication rates than surgery and are less *** RIC has a greater success rate than dilation *** reports showed that repeated RICs were needed to maintain patency of the *** report that single session RIC was applied only to treatment-naive patients with *** SUMMARY Two female patients presented with *** patient had advanced rectal cancer and the other had a refractory stenosis following surgery for endometriosis at sigmoid *** endoscopic RIC procedure was performed as follows.A single small incision was carefully made to increase the view of the proximal colon and the incision was expanded until the surgical stapling ***,we made a further circumferential excision with endoscopic knife along the inner border of the surgical staple *** the end of the procedure,the standard colonoscope was able to pass freely through the widened *** patients showed improved AS after a single session of RIC without immediate or delayed procedure-related ***-up colonoscopy at 7 and 8 mo after endoscopic RIC revealed intact anastomotic sites in both *** treatment-related adverse events or recurrence of the stenosis was demonstrated during follow-up periods of 20 and 23 *** The endoscopic RIC may play a role as one of treatment options for treatmentnaive AS with short stenotic lengths.

关键词： Colorectal surgery Anastomosis Stenosis Endoscopy Radial incision Case report

Clinical applicability of gastroscopy with narrow-band imaging for the diagnosis of Helicobacter pylori gastritis, precancerous gastric lesion, and neoplasia

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World Journal of Clinical Cases 2020年第14期8卷 2902-2916页

作者： Jun-Hyung Cho Seong Ran jeon So-Young Jin Digestive Disease Center Soonchunhyang University HospitalSeoul 04401South Korea Department of Pathology Soonchunhyang University HospitalSeoul 04401South Korea

Premalignant gastric lesions such as atrophic gastritis and intestinal metaplasia frequently occur in subjects with long-term Helicobacter pylori(***)*** regular arrangement of collecting venules(RAC)is seen in the normal gastric corpus,whereas mucosal swelling and redness without RAC are observed in ***-infected *** successful *** eradication,the presence of atrophic gastritis and/or gastric intestinal metaplasia(GIM)is a risk factor for gastric *** the development of advanced imaging technologies,recent studies have reported the usefulness of narrow-band imaging(NBI)for endoscopic diagnosis of atrophic gastritis and *** NBI endoscopy with magnification(M-NBI),atrophic gastritis is presented as irregular coiled microvessels and loss of gastric *** M-NBI endoscopic findings of GIM are a light blue crest and a white opaque *** on the microvascular patterns,fine network,core vascular,and unclear patterns are useful for predicting gastric dysplasia in polypoid *** diagnosis of early gastric cancer(EGC),a systematic classification using M-NBI endoscopy has been proposed on the basis of the presence of a demarcation line and an irregular microvascular/microsurface ***,M-NBI endoscopy has been found to be more accurate for determining the horizontal margin of EGC compared to conventional *** this review,we present up-to-date results on the clinical usefulness of gastroscopy with NBI for the diagnosis of *** gastritis,precancerous gastric lesion,and neoplasia.

关键词： Gastroscopy Narrow-band imaging Magnification Helicobacter pylori Atrophic gastritis Intestinal metaplasia Dysplasia Cancer