• Title/Summary/Keyword: Shunts

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The Study of Characteristics of Tubular Type Coaxial Shunt for High Current Measuring System (대전류 측정용 Tubular Coaxial Shunt 특성에 관한 연구)

  • Roh, Chang-Il;La, Dae-Ryeol;Kim, Sun-Koo;Jung, Heung-Soo;Kim, Won-Man;Lee, Dong-Jun
    • Proceedings of the KIEE Conference
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    • 2003.07b
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    • pp.834-836
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    • 2003
  • This paper describes the optimal design, construction and performance evaluation of coaxial shunts used in high current testing laboratory for current measuring system. These shunts, which are of tubular type coaxial shunts, the currents to be measured range from Amperes to several kiloAmperes, and the frequency of the signals has a bandwidth from DC to megaHertz. The shunt must have the mechanical strength to support the forces produced by the transient current, above all, the measuring capabilities of shunt are dependent upon short response time and it must be as free as possible of inductive effects. In this paper presents both characteristic of shunt and design of tubular type coaxial shunt.

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A Clinical Study of Congenital Intrahepatic Portosystemic Shunt Diagnosed in Neonatal Period (신생아기에 진단된 선천성 간내 문맥 전신성 단락의 임상적 고찰과 치료)

  • Kim, Ji-Young;Kim, Kyung-A;Lee, Yeon-Kyung;Ko, Sun-Young;Shin, Son-Moon;Han, Byung-Hee
    • Neonatal Medicine
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    • v.18 no.1
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    • pp.117-123
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    • 2011
  • Purpose: Congenital intrahepatic portosystemic shunts are rare disease and clinically asymptomatic shunts may be detected by chance on ultrasonogram before and after birth. We studied clinical course, treatment and prognosis of congenital intrahepatic portosystemic shunt at prenatal or neonatal period. Methods: Medical records of 8 patients which were diagnosed in intrahepatic portosystemic shunt in Cheil General Hospital from 2006 through 2010 were reviewed retrospectively. Results: Eight patients with congenital intrahepatic portosystemic shunts were identified. Six patients were diagnosed at prenatal radiological screening, including three cases of intrauterine growth restriction and two cases of preterm baby. One case with increased serum ammonia underwent coil embolization. In four cases including one case that presented elevated direct bilirubin, shunts were closed spontaneously within 11th month after birth. Two patients were diagnosed on abdominal sonogram after birth because of elevated direct hyperbilirubinemia, all of whom presented intrauterine growth restriction. Closure of shunts was confirmed during 4th month to 6th month. Conclusion: Congenital intrahepatic portosystemic shunts are clinically asymptomatic mostly and spontaneous closure is expected within 2 years age. But occasionally they have severe complication, so clinical and radiological observation is needed. Specially in cases of intrauterine growth retardation without evident cause, the possible diagnosis of congenital intrahepatic portosystemic shunts should be considered and prenatal and postnatal examination should be performed. When prenatal diagnosis is made, fetal wellbeing should be monitored periodically until spontaneous closure of shunts.

Left ventricular right atrial canal: report of 2 cases (좌심실우심방 단락치험 2)

  • 박국양
    • Journal of Chest Surgery
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    • v.17 no.2
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    • pp.184-188
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    • 1984
  • As OHS is prevalent on whole world, LV-RA shunts once thought as quite rare congenital heart disease are reported frequently. Two cases of LV-RA shunts were operated at N.M.C. in 1983: One of them combined VSD, the other membranous ventricular septal aneurysm protruding into right atrial chamber. In case 1, which was diagnosed correctly, right atriotomy was enough to close the defect under ECC, but in case 2, which was misdiagnosed as ASD preoperatively, atriotomy was added to ventriculotomy. The LV-RA defects were closed by U-shaped direct suture with Teflon felt pledget. Postoperative course was uneventful in both of them.

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Use of a Temporary Shunt as a Salvage Technique for Distal Extremity Amputations Requiring Repair by Vessel Grafting during Critical Ischemia

  • Ince, Bilsev;Dadaci, Mehmet;Altuntas, Zeynep
    • Archives of Plastic Surgery
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    • v.43 no.6
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    • pp.544-550
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    • 2016
  • Background Although the use of temporary shunts in proximal extremity amputations has been reported, no study has described the use of temporary shunts in distal extremity amputations that require vein grafting. Moreover, the total volume of blood loss when temporary shunts are used has not been reported. The aim of this study was to investigate the applicability of a temporary shunt for distal extremity amputations requiring repair by vessel grafting with an ischemia time of >6 hours. This study also aimed to determine the total volume of blood loss when temporary shunts were used. Methods Patients who underwent distal major extremity replantation and/or revascularization with a vessel graft and who experienced ischemia for 6-8 hours between 2013 and 2014 were included in the study. A 6-Fr suction catheter was cut to 5 cm in length after the infusion of heparin, and secured with a 5-0 silk suture between the distal and the proximal ends of the artery. While bleeding continued, the bones were shortened and fixed. After the complete restoration of circulation, the arterial shunt created using the catheter was also repaired with a vein graft. Results Six patients were included in this study. The mean duration of ischemia was 7.25 hours. The mean duration of suction catheter use during limb revascularization was 7 minutes. The mean transfusion volume was 7.5 units. No losses of the extremity were observed. Conclusions This procedure should be considered in distal extremity amputations requiring repair by vessel grafting during critical ischemia.

Quantitation of Intracardiac Right-to-Left Shunt by Radionuclide Angiocardiography (방사성동위원소 심혈관촬영술을 이용한 우-좌단락의 정량화에 관한 연구)

  • Bom, Hee-Seung;Lim, Sang-Moo;Oh, Yeon-Sang;Kim, Byung-Tae;Chung, June-Key;Lee, Myung-Chul;Koh, Chang-Soon;Lee, Young-Woo;Yun, Yong-Soo;Hong, Chang-Yee
    • The Korean Journal of Nuclear Medicine
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    • v.20 no.2
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    • pp.47-52
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    • 1986
  • A noninvasive procedure for diagnosis and quantitation of right-to-left intracardiac shunts will enhance the management of patients with cyanotic congenital heart disease. This study describes an application of radionuclide (RN) angiocardiography for quantitation of right-to-left shunt amount. Gamma variate model was fitted to radionuclide data recorded over the carotid artery. Data analysis was performed retrospectively in 35 patients who underwent cardiac catheterization within a week from the day of RN angiocardiography. Thirty one of the patient had right-to-left shunts and 4 of them had left-to-right shunts. Both the radionuclide and Fick measurements correlated well (r=0.93, 0.93, 0.89, p<0.01 in each measurements). Therefore, RN angiocardiography data may be used for accurate calculation of right-to-left shunts in cyanotic congenital heart disease patients.

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Acquired Portosystemic Shunts Secondary to Hepatic Microvascular Dysplasia in a Young Dog

  • Hwang, Taesung;An, Soyon;Kim, Ahreum;Han, Changhee;Huh, Chan;Lee, Hee Chun
    • Journal of Veterinary Clinics
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    • v.37 no.2
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    • pp.88-90
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    • 2020
  • A one year old spayed female Bichon Frise dog presented with gait abnormalities and seizure. Serum biochemical results showed elevated levels of alkaline phosphatase, alanine aminotransferase, and ammonia. Serum bile acid level was also increased to be over 30 μmol/L on preprandial. Urinalysis identified the presence of ammonium urate crystal. Abdominal ultrasonography and CT revealed aberrant, tortuous, and multiple small vessels connected to the caudal vena cava between left kidney and caudal vena cava. Macroscopic specific findings associated with extrahepatic congenital portosystemic shunts (PSS) or other liver diseases were not identified. Liver biopsy was performed. Histopathologic evaluation revealed hepatic lobular hypoplasia with portal arterial duplication and vascular shunts. Based on these finding, this case was diagnosed as multiple acquired PSS secondary to hepatic microvascular dysplasia (HMD) and hepatic encephalopathy. A liver biopsy is recommended to differentiate HMD from other liver diseases and to confirm HMD when a young dog has multiple acquired PSS.

A Sphaghetti Sign in the Abdominal Radiograph Consistent with Spleno-Systemic Shunts in a Cat

  • Oh, Donghyun;Hwang, Jaewoo;Yoon, Junghee;Choi, Mincheol
    • Journal of Veterinary Clinics
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    • v.37 no.4
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    • pp.227-230
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    • 2020
  • A 8-year-old spayed female Korean short-haired cat was presented with respiratory distress. CBC, serum chemistry analysis, plain radiography, and abdominal ultrasonography were performed. Besides hypertrophic cardiomyopathy (HCM) suspected by the thoracic radiograph, a tubular, tortuous soft tissue structure was detected at the region of the left retroperitoneal cavity on the abdominal radiograph. On the abdominal ultrasonography, a shunt vessel is identified caudo-lateral to the left kidney region. These findings are consistent with spleno-systemic shunts in cats. Furthermore, portal hypertension and diffuse hepatic lesion were also identified. Although the cause of a shunt vessel is not easy to diagnose, it is important to include spleno-systemic shunt into differential diagnosis list, when convoluted, tubular soft tissue opacity is seen on the digital radiography (DR). This report will allow clinicians to raise awareness of complications of portosystemic shunt (PSS) and better treat PSS suspected feline patients when the advanced modalities such as computed tomography and magnetic resonance imaging are not available.

EMTP Simulation for the Dynamic Analysis of a STATCOM-Shunts-OLTC Coordination in Substation (변전소 조상 설비간의 협조 제어를 위한 EMTP 과도해석모형 개발)

  • Jeong, Ki-Seok;Baek, Young-Sik;Park, Ji-Ho;Chang, Byung-Hoon;Lee, Hyun-Chul;Lee, Geun-Joon
    • Proceedings of the KIEE Conference
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    • 2009.07a
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    • pp.237_238
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    • 2009
  • This paper proposes coordinative control method between STATCOM installed within substation and other reactive power resources including Shunt Reactors and Shunt Capacitors and OLTC. Voltage/Reactive power control has various difficult aspects to control because of analysis and system dynamics error. This coordinative control method suggests practical algorithm regarding system voltage and reactive power status which is easy to implement in substation basis. In normal status, STATCOM-Shunts-OLTC are in operation. The proposed algorithm is tested and verified in EMTP/RV. And this is expected to be applied to control multiple reactive power devices combined with SCADA/EMS system.

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Ultrasonographic Examination for Intrahepatic Porto-systemic Shunts in Dogs (개의 간내성 문맥-전신성 단락의 초음파적 고찰)

  • 최지혜;안용주;이희천;황국진;이영원;엄기동;윤화영;최민철;권오경
    • Journal of Veterinary Clinics
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    • v.16 no.2
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    • pp.514-518
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    • 1999
  • Portosystemic shunts in 3 Dogs with respiratory sign of cough and with dementia signs characterized by hypersensitivity, salivation, and seizure were diagnosed at veterinary teaching hospital of Seoul National University. In radiographs, microhepatica was observed. In abdominal ultrasonography, abnormal intrahepatic connections between the portal vein and the systemic vessels and tortuous vascularity were found. There was no complication such as ammonium urate urolith in kidney or urinary bladder, These dogs were treated with medicine and protein-restricted diet.

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Endovascular Closure Resolves Trimethylaminuria Caused by Congenital Portosystemic Shunts

  • Ponce-Dorrego, Mar?a Dolores;Garzon-Moll, Gonzalo
    • Pediatric Gastroenterology, Hepatology & Nutrition
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    • v.22 no.6
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    • pp.588-593
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    • 2019
  • This study aimed to report three new cases of an association between two rare conditions, congenital portosystemic shunts (CPSS) and trimethylaminuria (TMAU), and the efficacy of endovascular closure of the CPSS for resolving TMAU. Between November 2014 and April 2017, 15 patients with CPSS were enrolled in this prospective study to assess the efficacy of percutaneous endovascular shunt closure. Three patients presented with clinical symptoms of TMAU that were confirmed by urine analysis of trimethylamine (TMA) and TMA n-oxide. One year after endovascular closure of the congenital portosystemic shunt, the same parameters were evaluated were obtained and the values were compared to the pretreatment values. The results indicated the disappearance of clinical symptoms of TMAU and normalization of the urine test parameters in two patients and no changes in one patient, who developed new portosystemic communications.