• Title/Summary/Keyword: Flow failure

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Treatment of Traumatic Carotid-Cavernous Fistulas using Debrun's Detachable Balloons (Debrun분리 풍선 카데타법에 의한 경동맥 해면동루의 치료)

  • Lee, Sang-Jin;Kim, Sun-Yong;Hwang, Mi-Soo;Chang, Jae-Chun;Park, Bok-Hwan
    • Journal of Yeungnam Medical Science
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    • v.6 no.2
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    • pp.91-101
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    • 1989
  • The goal of therapy in patients with traumatic carotid-cavernous fistulas is to occlude the fistula, preferably while maintaining the carotid blood flow. Since the introduction of the concepts of detachable balloon technique to occlude arteriovenous fistulas, the technique has become the treatment of choice in the management of traumatic carotid-cavernous fistulas. The major symptoms of traumatic CCFs are (1)pulsating exophthalmos, (2)orbital and cephalic bruit and murmur, (3) headache, (4) chemosis. (5) extraocular palsies, and (6) visual failure. Traumatic CCFs are combined with multiple associated lesions. We tried the occlusion of fistulas using Goldvalve balloons in 8 consecutive cases of traumatic CCF and the result of our experience is reported. Transarterial approach with manually-tied latex balloons is tried in all cases and the fistulas was successfully occluded in all cases. In 5 cases. the internal carotid artery was preserved and the arterial lumen was occluded along with fistula opening in :3 cases. In one case, surgical ligation was done because of symptoms recurred and incomplete occlusion of fistula. We experienced hemiparesis as a major complication in one case during occlusion tolerance test, which was remitted spontaneously. The results of Debrun balloon treatment were relatively excellent. We consider that the first choice of treatment of traumatic CCF is occlusion of the fistula by a detachable balloons.

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Data-driven event detection method for efficient management and recovery of water distribution system man-made disasters (상수도관망 재난관리 및 복구를 위한 데이터기반 이상탐지 방법론 개발)

  • Jung, Donghwi;Ahn, Jaehyun
    • Journal of Korea Water Resources Association
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    • v.51 no.8
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    • pp.703-711
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    • 2018
  • Water distribution system (WDS) pipe bursts are caused from excessive pressure, pipe aging, and ground shift from temperature change and earthquake. Prompt detection of and response to the failure event help prevent large-scale service interruption and catastrophic sinkhole generation. To that end, this study proposes a improved Western Electric Company (WECO) method to improve the detection effectiveness and efficiency of the original WECO method. The original WECO method is an univariate Statistical Process Control (SPC) technique used for identifying any non-random patterns in system output data. The improved WECO method multiples a threshold modifier (w) to each threshold of WECO sub-rules in order to control the sensitivity of anomaly detection in a water distribution network of interest. The Austin network was used to demonstrated the proposed method in which normal random and abnormal pipe flow data were generated. The best w value was identified from a sensitivity analysis, and the impact of measurement frequency (dt = 5, 10, 15 min etc.) was also investigated. The proposed method was compared to the original WECO method with respect to detection probability, false alarm rate, and averaged detection time. Finally, this study provides a set of guidelines on the use of the WECO method for real-life WDS pipe burst detection.

Evaluation of Flexural Properties of Indirect Gum-Shade Composite Resin for Esthetic Improvement (심미성 향상을 위한 간접수복용 Gum-Shade 복합레진의 굽힘 특성 평가)

  • Im, Yong-Woon;Hwang, Seong-Sig
    • Journal of dental hygiene science
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    • v.15 no.4
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    • pp.407-412
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    • 2015
  • This study investigated flexural properties of indirect Gum-shade composite resins for esthetic improvement. The material utilized in this study was Crea.lign, Twiny flow and Twiny paste (TP). Ten specimens were fabricated with a dimension of $25{\times}2{\times}2mm$ according to the ISO 4049. After fabrications, specimens were stored in the distilled water for 24 hours at the temperature of $37^{\circ}C$. Three-point bending test was performed in universal testing machine (Instron 3344; Instron, USA) at a crosshead speed of 1 mm/min until the failure occurred. TP exhibited a higher flexural strength (FS) and flexural modulus (FM) compared to the flowable materials. There were significant differences among the three materials in FS and FM. However, there was no significant difference in work of fracture (WOF) in all tested materials (p>0.05). In Weibull analysis, TP showed the greatest Weibull modulus which means a higher reliability of the materials. Also, Gum-shade composite resins revealed a strong correlation in all flexural properties. There was a positive correlation in FS-FM ($r^2=0.99$) and a negative correlation between FS-WOF and FM-WOF ($r^2>0.97$). Therefore, this confirmed that flexural property was important for mechanical behavior evaluation and useful information. To addition, this improved among mechanical properties correlation of materials as important factor.

Establishment of Paclitaxel-resistant Breast Cancer Cell Line and Nude Mice Models, and Underlying Multidrug Resistance Mechanisms in Vitro and in Vivo

  • Chen, Si-Ying;Hu, Sa-Sa;Dong, Qian;Cai, Jiang-Xia;Zhang, Wei-Peng;Sun, Jin-Yao;Wang, Tao-Tao;Xie, Jiao;He, Hai-Rong;Xing, Jian-Feng;Lu, Jun;Dong, Ya-Lin
    • Asian Pacific Journal of Cancer Prevention
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    • v.14 no.10
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    • pp.6135-6140
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    • 2013
  • Background: Breast cancer is a common malignant tumor which affects health of women and multidrug resistance (MDR) is one of the main factors leading to failure of chemotherapy. This study was conducted to establish paclitaxel-resistant breast cancer cell line and nude mice models to explore underlying mechanisms of MDR. Methods: The breast cancer drug-sensitive cell line MCF-7 (MCF-7/S) was exposed in stepwise escalating paclitaxel (TAX) to induce a resistant cell line MCF-7/TAX. Cell sensitivity to drugs and growth curves were measured by MTT assay. Changes of cell morphology and ultrastructure were examined by optical and electron microscopy. The cell cycle distribution was determined by flow cytometry. Furthermore, expression of proteins related to breast cancer occurrence and MDR was tested by immunocytochemistry. In Vivo, nude mice were injected with MCF-7/S and MCF-7/TAX cells and weights and tumor sizes were observed after paclitaxel treatment. In addition, proteins involved breast cancer and MDR were detected by immunohistochemistry. Results: Compared to MCF-7/S, MCF-7/TAX cells had a higher resistance to paclitaxel, cross-resistance and prolonged doubling time. Moreover, MCF-7/TAX showed obvious alterations of ultrastructure. Estrogen receptor (ER) expression was low in drug resistant cells and tumors while expression of human epidermal growth factor receptor 2 (HER2) and Ki-67 was up-regulated. P-glycoprotein (P-gp), lung resistance-related protein (LRP) and glutathione-S-transferase-${\pi}$ (GST-${\pi}$) involved in the MDR phenotype of resistant cells and tumors were all overexpressed. Conclusion: The underlying MDR mechanism of breast cancer may involve increased expression of P-gp, LRP and GST-${\pi}$.

A novel PRF1 gene mutation in a fatal neonate case with type 2 familial hemophagocytic lymphohistiocytosis

  • Kim, Jae Yeon;Shin, Jeong Hee;Sung, Se In;Kim, Jin Kyu;Jung, Ji Mi;Ahn, So Yoon;Kim, Eun Sun;Seo, Ja-Young;Kang, Eun-Sook;Kim, Sun-Hee;Kim, Hee-Jin;Chang, Yun Sil;Park, Won Soon
    • Clinical and Experimental Pediatrics
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    • v.57 no.1
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    • pp.50-53
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    • 2014
  • Hemophagocytic lymphohistiocytosis (HLH) occurs in the primary form (genetic or familial) or secondary form (acquired). The familial form of HLH (FHL) is a potentially fatal autosomal recessive disorder that occurs because of constitutional defects in cell-mediated cytotoxicity. Here, we report a fatal neonatal case of type 2 FHL (FHL2) that involved a novel frameshift mutation. Clinically, the newborn presented with severe sepsis-like features and required mechanical ventilation and continuous venovenous hemodiafiltration. Flow cytometry analysis showed marked HLH and complete absence of intracytoplasmic perforin expression in cytotoxic cells; therefore, we performed molecular genetic analyses for PRF1 mutations, which showed that the patient had a compound heterozygous mutation in PRF1, that is, c.65delC ($p.Pro22Argfs^*2$) and c.1090_1091delCT ($p.Leu364Glufs^*93$). Clinical and genetic assessments for FHL are required for neonates with refractory fever and progressive multiple organ failure, particularly when there is no evidence of microbiological or metabolic cause.

Incidence of Vesicoureteral Reflux in Asymptomatic Siblings of Patients with Reflux (방광요관역류 환아의 무증상 형제 자매의 역류 빈도 조사)

  • Kim, Jong Shik;Koo, Ja Wook
    • Clinical and Experimental Pediatrics
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    • v.45 no.12
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    • pp.1540-1545
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    • 2002
  • Purpose : Vesicoureteral reflux(VUR) is defined as a retrograde flow of urine from the bladder into the upper urinary tract. It has been shown to predispose patients to hypertension, renal scarring, and end-stage renal failure if not recognized and treated. The observation that VUR occurs in siblings of children with reflux at a significantly higher rate than the general pediatric population has been recognized for many years and VUR was detected in 26% to 51% of siblings of patients with VUR. The purpose of this study is to determine the incidence of VUR in asymptomatic siblings of children with VUR and to see if this form of screening would be practical. Methods : We retrospectively reviewed the records of 28 patients with VUR and their siblings. The total number of asymptomatic siblings investigating VUR were 28 persons. All patients and siblings were evaluated for VUR by a voiding cystourethrography and all patients and siblings with VUR were performed $^{99m}Tc$ 2,3-dimercaptosuccinic acid renal scan. Results : A total of 28 patients(14 boys, 14 girls) with VUR were studied; the mean patient age was 2.7 years(range 1 month to 8.4 years). The total number of asymptomatic siblings investigating VUR were 28 persons(17 boys, 11 girls) and the mean age was 3.3 years(range 2 months to 7.4 years). Renal scar was detected in 20 of 28(71.4%) patients with VUR. VUR was noted in three of 28(10.7%) siblings and renal scar was detected in one of three siblings with VUR. Conclusion : In this study, the predictive value of a positive family history alone in identifying VUR was 10.7%. This incidence suggests more investigation of asymptomatic siblings and continued study of this group of patients at risk is needed for clarifying the family screening of patients with VUR.

Modified SBEACH Model for Predicting Erosion and Accretion in front of Seadike (수정 SBEACH 모델에 의한 호안 전면의 침퇴적 예측)

  • Han, Jae-Myong;Kim, Kyu-Han;Shin, Sung-Won;Deguchi, Ichiro
    • Journal of Korean Society of Coastal and Ocean Engineers
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    • v.23 no.6
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    • pp.482-488
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    • 2011
  • Seadike is a coastal structure constructed in the rear region of the foreshore to maximize its usability by preventing direct effect of wave. The expected construction field is determined under the design wave and tidal condition where minor wave overtopping is anticipated. Thus, the location of seadike is generally fixed at the highest site of the surrounding area with seadike crest height controlling the permissible range of wave overtopping volume. But a lot of times, frontal sand beach of the seadike continuously deforms due to incident waves, resulting failure in maintaining its initial slope. The erosion and deposition of the seadike front cause changes in the crest height and volume of wave overtopping and decrease in the setting depth of the seadike, which endangers seadike region as a result. In this study, the relation of local scouring and setting depth of the seadike front in the run-up region is examined by using 2D hydraulic model tests and numerical simulations by modified SBEACH model. As a result, the study learned that if appropriate boundary condition is applied to the modified SBEACH model, it is possible to create practical estimations on the local scouring at the seadike foot when erosive waves flow into the region.

The Reconstruction of Foot using Medial Plantar Flap (내측 족저 피판을 이용한 족부의 재건)

  • Chung, Duke-Whan;Lee, Jae-Hoon
    • Archives of Reconstructive Microsurgery
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    • v.11 no.2
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    • pp.153-161
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    • 2002
  • Purpose : Plantar surfaces, calcaneal area, and region of Achilles insertion, which are extremely related with weight-bearing area and shoes application, must be reconstructed with glabrous and strong fibrous skin. Numerous methods of reconstructing defects of these regions have been advocated, but the transfer of similar local tissue as a cutaneous flap with preservation of sensory potential would best serve the functional needs of the weight-bearing and non-weight-bearing surfaces of this region. Therefore it is recommended to use the limited skin of medial surface of foot that is similar to plantar region and non-weight-bearing area. In this paper we performed the medial plantar flap transfered as a fasciocutaneous island as one alterative for moderate-sized defects of the plantar forefoot, plantar heel, and area around the ankle in 25 cases and report the result, availability and problem of medial plantar flap. Materials and methods : We performed proximally based medial plantar flap in 22 cases and reverse flow island flap in 3 cases. Average age was $36.5(4{\sim}70)$ years and female was 3 cases. The causes of soft tissue defect were crushing injury on foot 4 cases, small bony exposure at lower leg 1 case, posterior heel defect with exposure of calcaneus 8 cases, severe sore at heel 2 cases, skin necrosis after trauma on posterior foot 4 cases, and defect on insertion area of Achilles tendon 6cases. Average follow up duration was 1.8(7 months-9.5 years) years. Results: Medial plantar flaps was successful in 22 patients. 18 patients preserved cutaneous branches of medial plantar nerve had sensation on transfered flap but diminished sensation or dysesthesia. At the follow up, we found there were no skin ulceration, recurrence of defect or skin breakdown in all 18 patients. But there was one case which occurred skin ulceration postoperatively among another 4 cases not contained medial plantar nerve. At the last follow up, all patients complained diminished sensation and paresthesia at medial plantar area distally to donor site, expecially with 4 patients having severe pain and discomfort during long-time walking. Conclusion : Medial plantar island flap based on medial plantar neurovascualr pedicle have low failure rate with strong fibrous skin and preserve sensibility of flap, so that it is useful method to reconstruct the skin and soft tissue defect of foot. But it should be emphasized that there are some complications such like pain and paresthesia by neuropraxia or injury of medial plantar nerve at more distal area than donor site. We may consider that medial plantar flap have limited flap size and small arc of rotation, and require skin graft closure of the donor defect and must chose this flap deliberately.

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Findings of Digital Subtraction Angiography after Vascularized Fibular Grafting for Osteonecrosis of Femoral Head (대퇴골두 무혈성 괴사에 대한 혈관부착 비골 이식술 후 디지털 감산 혈관조영술 소견)

  • Lee, Kee-Haeng;Kim, Youn-Soo;Lee, Hae-Giu;Ok, Ji-Hoon;Kim, Bae-Kyun;Kim, Hyoung-Min
    • Archives of Reconstructive Microsurgery
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    • v.13 no.2
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    • pp.130-135
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    • 2004
  • Purpose : To observe the patency of anastomosis site and the findings of circulation of grafted fibula in osteonecrosis of femoral head treated with vascularized fibular graft by use of digital subtraction angiography. Materials and Methods : 17 cases of 11 patients who underwent vascularized fibula graft for osteonecrosis of femoral head. We performed digital subtraction angiography(DSA) for them at second week postoperatively in 12 cases, at sixth week in 1 case, at sixth month in 2 cases, at twelfth month in 1 case, and eighteenth month in 1 case which had been got DSA at second week before. We observe the patency of pedicle, and the circulation of grafted fibula such as periosteal and intraosseous vessels with time. Results : All cases except one which were thought failure of selective angiogram showed good passage of blood flow through anstomosed pedicle on DSA. We found the differences in appearance of circulation of grafted fibula with time. DSA at 2nd and 6th week postoperatively revealed both of periosteal and intraosseous vessels along the fibula and blood pooling at the tip of fibula. DSA at 6th month showed maintenance of periosteal and intraosseous vessels along the fibula but did not clearly reveal blood pooling at the tip of fibula. The findings of DSA at 12th and 18th month were similar each other. The periosteal vessels were not seen as the grafted fibular bone were incorporated into surrounding femoral bone but intraosseous vessels were still seen. Conclusion : It was thought that DSA could be used for evaluation of the status of pedicle including anastomsed site and vessels of grafted fibula with time. The periosteal vessels of fibula were decreased with time but intraosseous vessels were still seen until 18th month after vascularized fibula graft.

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Change of Fractured Rock Permeability due to Thermo-Mechanical Loading of a Deep Geological Repository for Nuclear Waste - a Study on a Candidate Site in Forsmark, Sweden

  • Min, Ki-Bok;Stephansson, Ove
    • Proceedings of the Korean Radioactive Waste Society Conference
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    • 2009.06a
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    • pp.187-187
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    • 2009
  • Opening of fractures induced by shear dilation or normal deformation can be a significant source of fracture permeability change in fractured rock, which is important for the performance assessment of geological repositories for spent nuclear fuel. As the repository generates heat and later cools the fluid-carrying ability of the rocks becomes a dynamic variable during the lifespan of the repository. Heating causes expansion of the rock close to the repository and, at the same time, contraction close to the surface. During the cooling phase of the repository, the opposite takes place. Heating and cooling together with the, virgin stress can induce shear dilation of fractures and deformation zones and change the flow field around the repository. The objectives of this work are to examine the contribution of thermal stress to the shear slip of fracture in mid- and far-field around a KBS-3 type of repository and to investigate the effect of evolution of stress on the rock mass permeability. In the first part of this study, zones of fracture shear slip were examined by conducting a three-dimensional, thermo-mechanical analysis of a spent fuel repository model in the size of 2 km $\times$ 2 km $\times$ 800 m. Stress evolutions of importance for fracture shear slip are: (1) comparatively high horizontal compressive thermal stress at the repository level, (2) generation of vertical tensile thermal stress right above the repository, (3) horizontal tensile stress near the surface, which can induce tensile failure, and generation of shear stresses at the comers of the repository. In the second part of the study, fracture data from Forsmark, Sweden is used to establish fracture network models (DFN). Stress paths obtained from the thermo-mechanical analysis were used as boundary conditions in DFN-DEM (Discrete Element Method) analysis of six DFN models at the repository level. Increases of permeability up to a factor of four were observed during thermal loading history and shear dilation of fractures was not recovered after cooling of the repository. An understanding of the stress path and potential areas of slip induced shear dilation and related permeability changes during the lifetime of a repository for spent nuclear fuel is of utmost importance for analysing long-term safety. The result of this study will assist in identifying critical areas around a repository where fracture shear slip is likely to develop. The presentation also includes a brief introduction to the ongoing site investigation on two candidate sites for geological repository in Sweden.

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