• 제목/요약/키워드: Dilation flow

검색결과 66건 처리시간 0.034초

Centrifuge modelling of pile-soil interaction in liquefiable slopes

  • Haigh, Stuart K.;Gopal Madabhushi, S.P.
    • Geomechanics and Engineering
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    • 제3권1호
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    • pp.1-16
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    • 2011
  • Piles passing through sloping liquefiable deposits are prone to lateral loading if these deposits liquefy and flow during earthquakes. These lateral loads caused by the relative soil-pile movement will induce bending in the piles and may result in failure of the piles or excessive pile-head displacement. Whilst the weak nature of the flowing liquefied soil would suggest that only small loads would be exerted on the piles, it is known from case histories that piles do fail owing to the influence of laterally spreading soils. It will be shown, based on dynamic centrifuge test data, that dilatant behaviour of soil close to the pile is the major cause of these considerable transient lateral loads which are transferred to the pile. This paper reports the results of geotechnical centrifuge tests in which models of gently sloping liquefiable sand with pile foundations passing through them were subjected to earthquake excitation. The soil close to the pile was instrumented with pore-pressure transducers and contact stress cells in order to monitor the interaction between soil and pile and to track the soil stress state both upslope and downslope of the pile. The presence of instrumentation measuring pore-pressure and lateral stress close to the pile in the research described in this paper gives the opportunity to better study the soil stress state close to the pile and to compare the loads measured as being applied to the piles by the laterally spreading soils with those suggested by the JRA design code. This test data shows that lateral stresses much greater than one might expect from calculations based on the residual strength of liquefied soil may be applied to piles in flowing liquefied slopes owing to the dilative behaviour of the liquefied soil. It is shown at least for the particular geometry studied that the current JRA design code can be un-conservative by a factor of three for these dilation-affected transient lateral loads.

사궁산(莎芎散)이 실험동물(實驗動物)의 지혈(止血), 뇌압(腦壓), 혈압(血壓) 및 심혈관계(心血管系)에 미치는 영향(影響) (Effects of Sagungsan on the Hemostasis, Intracranial Pressure, Blood Pressure and Cardiovascular System in Expreimental Animals)

  • 안일회;박영순;김세길
    • 대한한방내과학회지
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    • 제15권1호
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    • pp.80-98
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    • 1994
  • According to the original documents, Sagungsan is considered as an effective drug for controlling the hypertensive epistaxis induced by tension of autonomic nerve and it's hyperfunction. The present experiment was designed to understand the effect of Sagungsan extract on the hemostatic action, intracranial pressure, blood pressure and cardiovascular system in experimental animals. And thus the bleeding time, prothrombin time, capillary dilation, blood pressure, Intracranial pressure, and enzymatic analysis of the ATPase activities were studied. The result obtained here were as followings: 1. Sagungsan water extract reduced the bleeding time in mouse, and prolonged the prothrombin time in rabbits. 2. The drug extract increased the tail volume by capillary dilation in rats. 3. The drug extract inhibited the increase of intracranial pressure and arterial blood pressure in rabbits. 4. At the early time, the increase of arterial blood pressure by the drug extract significantly inhibited by pretreated atropin and regitine in rabbits. 5. The drug extract relaxed the smooth muscle by stimulating the Mg2+-Ca2+-ATPase activities of gastric sarcoplasmic reticulum isolated from rabbit stomach. 6. The drug extract stimulated the heart contraction by inhibiting the $Mg^{2+}-Ca^{2+}-ATPase$ activities of cardiac sarcoplasmic reticulum isolated from rabbit heart. The inhibitory mechanism was reversible and noncompatitive. 7. The drug extract increased the hepatic blood volume by stimulating the hepatic total ATPase activities and hepatic metabolism. 8. The drug extract acted as a tranquilizer by inhibiting the neural Na+-K+-ATPase activity. According to the results, Sagungsan water extract dilated the capillaries, stimulated the heart beat, and thus increased the blood flow with decreasing the intracranial pressure and blood pressure. These effects stanches the epistaxis collectively.

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이형협심증 환자의 혈관내피세포 기능저하에 영향을 미치는 심혈관질환 위험인자 (Cardiovascular Risk Factors Predicting Endothelial Dysfunction in Patients with Variant Angina)

  • 조숙희;황선영;정명호
    • 성인간호학회지
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    • 제21권5호
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    • pp.477-488
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    • 2009
  • Purpose: This study was conducted to identify the clinical characteristics and risk factors on the occurrence of variant angina, and to examine the predicting factors on the vascular endothelial dysfunction of the patients with variant angina. Methods: A total of 134 patients diagnosed with variant angina were recruited from 2006 to 2008. The degrees of endothelial dysfunction were measured and recorded by the researcher using the values of flow-mediated vasodilation of their brachial arteries and Nitroglycerine-mediated dilation. Subjects' demographic data and risk factors were gathered after obtaining informed consent, and their electronic medical records were reviewed to collect laboratory data. Results: The mean age was $54.2{\pm}9.6$ years and 52% was male patients. More than 50% of the male patients were cigarette smokers and had hypercholesterolemia. 84% of the male patients and 70% of the female patients had more than one risk factor of cardiovascular disease. A stepwise multiple regression analysis showed that smoking and hypercholesterolemia predicted the decrease of flow-mediated vasodilation (Adjusted $R^2$ = .204, p < .001). Conclusion: Tailored educational interventions for smoking cessation and cholesterol management are needed to prevent recurrence of angina attack for patients with variant angina and to prevent cardiovascular disease for middle-aged workers.

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Effect of normal load on the crack propagation from pre-existing joints using Particle Flow Code (PFC)

  • Haeri, Hadi;Sarfarazi, Vahab;Zhu, Zheming
    • Computers and Concrete
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    • 제19권1호
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    • pp.99-110
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    • 2017
  • In this paper, the effect of normal load on the failure mechanism of echelon joint has been studied using PFC2D. In the first step, calibration of PFC was undertaken with respect to the data obtained from experimental laboratory tests. Then, six different models consisting various echelon joint were prepared and tested under two low and high normal loads. Furthermore, validation of the simulated models were cross checked with the results of direct shear tests performed on non-persistent jointed physical models. The simulations demonstrated that failure patterns were mostly influenced by normal loading, while the shear strength was linked to failure mechanism. When ligament angle is less than $90^{\circ}$, the stable crack growth length is increased by increasing the normal loading. In this condition, fish eyes failure pattern occur in rock bridge. With higher ligament angles, the rock bridge was broken under high normal loading. Applying higher normal loading increases the number of fracture sets while dilation angle and mean orientations of fracture sets with respect to ligament direction will be decreased.

Right to Left Atrial Septum Defect Compounded with Patent Ductus Arteriosus in a Maltese Dog

  • Ahn, Sung-Taek;Kim, Myung-Jun;Yoon, Won-Kyoung;Suh, Sang-il;Hyun, Changbaig
    • 한국임상수의학회지
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    • 제34권2호
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    • pp.90-93
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    • 2017
  • A nine-month-old intact female Maltese dog (body weight: 1.5 kg) presented with frequent syncopal episodes (1-2/day), exercise intolerance, and dyspnea. Cardiomegaly with marked dilation of right and left atria along with ascites was indicated on radiography. Tricuspid regurgitant jets (4.36 m/s), pulmonary regurgitant jets (3.4 m/s), left-to-right shunting flow at the ductus arteriosus, and an atrial septal defect were observed on echocardiography. A bubble study with agitated saline found right-to-left shunting at the interatrial septum. Based on diagnostic studies, the dog was diagnosed with right-to-left atrial septum defect (ASD) compounded with patent ductus arteriosus (PDA). The treatment was directed to reduce the pulmonary hypertension, improve cardiac performance, and lower fluid retention. Despite medical treatment for 2 months, the dog died of sudden cardiac arrest. Herein, we describe a very rare case of right-to-left ASD compounded with PDA.

Pulmonic stenosis corrected by balloon valvuloplasty in a Maltese dog

  • Lee, Seung-Gon;Moon, Hyeong-Sun;Hyun, Changbaig
    • 대한수의학회지
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    • 제47권3호
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    • pp.333-336
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    • 2007
  • A 6-month-old intact male Maltese dog (2.5 kg of body weight) was presented with the primary complaint of heart murmur and exercise intolerance. Diagnostic studies revealed severe pulmonic stenosis. Since the pressure gradient in stenotic pulmonic valve area was higher than 200 mmHg (maximum flow velocity = 7.1 m/s), the dog was underwent balloon valvuloplasty. With this procedure, the peak pulmonic velocity was reduced to 3.0 m/s (PG = 36 mmHg). Periodic re-evaluations performed in monthly interval revealed no further deterioration even after 4 month of procedure. This is the first case report of pulmonic stenosis fixed by non-surgical balloon valvuloplasty in Korea.

Siberian Husky 견에서 팔로사징 진단 증례 (A Case of Tetralogy of Fallot in a Siberian Husky Dog)

  • 이해운;엄기동;성윤상;박진희;김정은;오태호;이희천
    • 한국임상수의학회지
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    • 제21권3호
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    • pp.314-318
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    • 2004
  • A 7-month-old 8.2 kg female Siberian Husky with history of exercise intolerance, delayed growth, and tachypnea was presented to Veterinary Medical Teaching Hospital, Kyungpook National University. A holosystolic murmur was identified in cardiac ausculation. In electrocardiography, thoracic radiographs, and ultrasonography, a right axis deviation, enlarged right ventricle, stenotic main pulmonary artery, large ventricular septal defect, marked right ventricle hypertrophy, and overriding aorta with dilation were identified. The color Doppler examination showed the left-to-right shunting of blood via interventricular septal defect and the blood flow streams converging from the right and left ventricles into the aorta. The dog was diagnosed as tetralogy of Fallot. The current state of the dog is well-tolerated without any specific medication.

Arachidonic Acid의 개 신장기능에 미치는 영향 (Effect of Arachidonic Acid on Renal Function of Dog)

  • 고석태;박화숙
    • 약학회지
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    • 제34권4호
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    • pp.252-261
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    • 1990
  • Arachidonic acid which is precursor of prostaglandins, when administered ($100.0\;{\mu}g/kg$, or $100.0\;{\mu}g/kg/min$) intravenously, did not influence on renal function of dog. Arachidonic acid, when infused ($10.0\;{\mu}g/kg/min$) into a renal artery, produced marked diuretic action accompanied with augmentation of renal plasma flow and with little changed glomerular filtration rate, and exhibited the increased clearances of osmolar substance and free water, and the decreased reabsorption rates of sodium and potassium in renal tubules in only experimental kidney, but did not influenced at all in control kindey. The diuretic acition of arachidonic acid infused into a renal artery was not affected by pretreatment of indomethacin (10.0 mg/kg. i.v) which is inhibitor of cyclooxygenase. Above results suggest that arachidonic acid infused into a renal artery produced diuretic action through direct renal hemodynamic changes, that is mediated by reduction of postglomerular resistance being caused by dilation of vas efferense.

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개에서 심방중격결손의 증례 (Atrial Septal Defect in Dogs)

  • 정주현;엄기동;장광호;오태호;이영원;장동우;윤정희
    • 한국임상수의학회지
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    • 제19권1호
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    • pp.110-113
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    • 2002
  • An atrial septal defect (ASD) is a congenital hole in the atrial septum that allows flow between the two atria. Small ASDs are usually well-tolerated defects and do not result in significant clinical abnormalities. In large ASDs or in the presence of other cardiac defects, clinically significancy is increased. Atrial septal defects in 2 Dogs with cardiac and respiratory signs were diagnosed at seoul animal medical center. In ascultation, systolic murmur and the splitting of second heart sound were heard at pulmonary or tricuspid valve region. In radiograph, right-sided cardiomegaly, pulmonary artery dilation, increased pulmonary vasculature makings, and pleural effusion or pulmonary edema signs were observed. In echocardiography, the region, location and size of septal defect was identified. Also, the direction and degree of shunt was measured. These dogs were treated with medicine for cardiac failure. One dog is well-tolerated, the other dog died.

Vasodilatory Effect of Complex Saponin Extracted from Platycodon grandiflorum and Glycyrrhiza uralensis Mixture Extract

  • Jung-Hwan Nam
    • 한국자원식물학회지
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    • 제35권6호
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    • pp.713-719
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    • 2022
  • Platycodon grandiflorum and Glycyrrhiza uralensis contain several bioactive compounds, such as saponin, oleanolic acid, and flavone. P. grandiflorum and G. uralensis have traditionally been used to treat disorders related to blood pressure, diabetes, and counteracting poison, and they have antinociceptive and antiinflammatory properties. However, the validity of complex saponin's vasodilatory effect has not been scientifically investigated. Therefore, this study explores the vasodilatory effect of complex saponin extracted from P. grandiflorum and G. uralensis mixture extract on rabbit carotid arteries. To this end, arterial rings with intact or damaged endothelium were used in an organ bath experiment and contracted by endothelin. Complex saponins, the major active constituents of P. grandiflorum and G. uralensis mixture extract, exhibited a moderate vasodilatory effect on the rabbit's basilar arteries. Therefore, treatment with complex saponin extracted from P. grandiflorum and G. uralensis mixture extract may selectively accelerate cerebral blood flow through basilar arterial dilation. Overall, the findings suggest that the extracted complex saponins can serve as vasodilator sources.