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Sample records for acute shunt malfunction

  1. Episodic ventriculomegaly due to hypernatremia mimicking shunt malfunction: case report.

    Jernigan, Sarah C; Stone, Scellig S D; Aronson, Joshua P; Putman, Melissa; Proctor, Mark R

    2015-10-01

    Patients with shunted hydrocephalus presenting with altered mental status and ventriculomegaly are generally considered to be in shunt failure requiring surgical treatment. The authors describe a case of shunted hydrocephalus secondary to a disseminated neuroectodermal tumor in a pediatric patient in whom rapid fluctuations in sodium levels due to diabetes insipidus repeatedly led to significant changes in ventricle size, with invasively confirmed normal shunt function and low intracranial pressure. This clinical picture exactly mimics shunt malfunction, requires urgent nonsurgical therapy, and underscores the importance of considering serum osmolar abnormalities in the differential diagnosis for ventriculomegaly. PMID:26186358

  2. Risk factors for shunt malfunction in pediatric hydrocephalus: a multicenter prospective cohort study.

    Riva-Cambrin, Jay; Kestle, John R W; Holubkov, Richard; Butler, Jerry; Kulkarni, Abhaya V; Drake, James; Whitehead, William E; Wellons, John C; Shannon, Chevis N; Tamber, Mandeep S; Limbrick, David D; Rozzelle, Curtis; Browd, Samuel R; Simon, Tamara D

    2016-04-01

    OBJECT The rate of CSF shunt failure remains unacceptably high. The Hydrocephalus Clinical Research Network (HCRN) conducted a comprehensive prospective observational study of hydrocephalus management, the aim of which was to isolate specific risk factors for shunt failure. METHODS The study followed all first-time shunt insertions in children younger than 19 years at 6 HCRN centers. The HCRN Investigator Committee selected, a priori, 21 variables to be examined, including clinical, radiographic, and shunt design variables. Shunt failure was defined as shunt revision, subsequent endoscopic third ventriculostomy, or shunt infection. Important a priori-defined risk factors as well as those significant in univariate analyses were then tested for independence using multivariate Cox proportional hazard modeling. RESULTS A total of 1036 children underwent initial CSF shunt placement between April 2008 and December 2011. Of these, 344 patients experienced shunt failure, including 265 malfunctions and 79 infections. The mean and median length of follow-up for the entire cohort was 400 days and 264 days, respectively. The Cox model found that age younger than 6 months at first shunt placement (HR 1.6 [95% CI 1.1-2.1]), a cardiac comorbidity (HR 1.4 [95% CI 1.0-2.1]), and endoscopic placement (HR 1.9 [95% CI 1.2-2.9]) were independently associated with reduced shunt survival. The following had no independent associations with shunt survival: etiology, payer, center, valve design, valve programmability, the use of ultrasound or stereotactic guidance, and surgeon experience and volume. CONCLUSIONS This is the largest prospective study reported on children with CSF shunts for hydrocephalus. It confirms that a young age and the use of the endoscope are risk factors for first shunt failure and that valve type has no impact. A new risk factor-an existing cardiac comorbidity-was also associated with shunt failure. PMID:26636251

  3. Ventricular enlargement due to acute hypernatremia in a patient with a ventriculoperitoneal shunt.

    Andres, Robert H; Pendharkar, Arjun V; Kuhlen, Dominique; Mariani, Luigi

    2010-07-01

    Patients requiring CSF shunts frequently have comorbidities that can influence water and electrolyte balances. The authors report on a case involving a ventriculoperitoneal shunt in a patient who underwent intravenous hyperhydration and withdrawal of vasopressin substitution prior to scheduled high-dose chemotherapy regimen for a metastatic suprasellar germinoma. After acute neurological deterioration, the patient underwent CT scanning that demonstrated ventriculomegaly. A shunt tap revealed no flow and negative opening pressure. Due to suspicion of proximal shunt malfunction, the comatose patient underwent immediate surgical exploration of the ventricle catheter, which was found to be patent. However, acute severe hypernatremia was diagnosed during the procedure. After correction of the electrolyte disturbances, the patient regained consciousness and made a good recovery. Although rare, the effects of acute severe hypernatremia on brain volume and ventricular size should be considered in the differential diagnosis of ventriculoperitoneal shunt failure. PMID:19911884

  4. Laparoscopic Cholecystectomy for Acute Calcular Cholecystitis in a Patient with Ventriculoperitoneal Shunt: A Case Report and Literature Review

    Abdullah A. Albarrak

    2015-01-01

    Full Text Available Management of patients who have ventriculoperitoneal shunt presenting with acute calcular cholecystitis has remained a clinical challenge. In this paper, the hospital course and the follow-up of a patient presenting with acute calcular cholecystitis and ventriculoperitoneal shunt managed with laparoscopic cholecystectomy are presented followed by literature review on the management of acute calcular cholecystitis in patients who have ventriculoperitoneal shunts.

  5. Effect of Prone Position on Regional Shunt, Aeration, and Perfusion in Experimental Acute Lung Injury

    Richter, Torsten; Bellani, Giacomo; Harris, R. Scott; Melo, Marcos F. Vidal; Winkler, Tilo; Venegas, Jose G.; Musch, Guido

    2005-01-01

    Rationale: The prone position is used to improve gas exchange in patients with acute respiratory distress syndrome. However, the regional mechanism by which the prone position improves gas exchange in acutely injured lungs is still incompletely defined. Methods: We used positron emission tomography imaging of [13N]nitrogen to assess the regional distribution of pulmonary shunt, aeration, perfusion, and ventilation in seven surfactant-depleted sheep in supine and prone positions. Results: In t...

  6. Emergency management of an acute tension pneumocephalus following ventriculoperitoneal shunt surgery for normal pressure hydrocephalus.

    Aydoseli, Aydın; Akcakaya, Mehmet Osman; Aras, Yavuz; Boyali, Osman; Unal, Omer Faruk

    2013-01-01

    Tension pneumocephalus is a rare and life threatening complication of intracranial surgical procedures, and requires immediate recognition and surgical intervention. Tension pneumocephalus following ventriculoperitoneal shunt surgery is extremely rare and commonly seen as a delayed complication. To our knowledge, early postoperative tension pneumocephalus after shunt surgery was reported only in one other publication. We present a case of acute tension pneumocephalus following ventriculoperitoneal shunt surgery for normal pressure hydrocephalus, which was managed well with close neurological follow-up and rapid surgical intervention. The use of the portable CT scanner in this case saved significant time, without the transport of the patient to the radiology unit, made early surgical intervention possible, and prevented morbidity and mortality. PMID:24101285

  7. Rapid resolution of an acute subdural hematoma by increasing the shunt valve pressure in a 63-year-old man with normal-pressure hydrocephalus with a ventriculoperitoneal shunt: a case report and literature review

    Hayes Jackson

    2012-11-01

    Full Text Available Abstract Introduction Symptomatic subdural hematoma development is a constant concern for patients who have undergone cerebrospinal fluid shunting procedures to relieve symptoms related to normal-pressure hydrocephalus. Acute subdural hematomas are of particular concern in these patients as even minor head trauma may result in subdural hematoma formation. The presence of a ventricular shunt facilitates further expansion of the subdural hematoma and often necessitates surgical treatment, including subdural hematoma evacuation and shunt ligation. Case presentation We present the case of a 63-year-old North American Caucasian man with normal-pressure hydrocephalus with an adjustable valve ventriculoperitoneal shunt who developed an acute subdural hematoma after sustaining head trauma. Conservative treatment was favored over operative evacuation because our patient was neurologically intact, but simple observation was considered to be too high risk in the setting of a low-pressure ventriculoperitoneal shunt. Thus, the valve setting on the ventriculoperitoneal shunt was increased to its maximum pressure setting in order to reduce flow through the shunt and to mildly increase intracranial pressure in an attempt to tamponade any active bleeding and limit hematoma expansion. A repeat computed tomography scan of the head six days after the valve adjustment revealed complete resolution of the acute subdural hematoma. At this time, the valve pressure was reduced to its original setting to treat symptoms of normal-pressure hydrocephalus. Conclusions Programmable shunt valves afford the option for non-operative management of acute subdural hematoma in patients with ventricular shunts for normal-pressure hydrocephalus. As illustrated in this case report, increasing the shunt valve pressure may result in rapid resolution of the acute subdural hematoma in some patients.

  8. Acute intraoperative neurogenic myocardial stunning during intracranial endoscopic fenestration and shunt revision in a pediatric patient.

    Dragan, Kristen Elizabeth; Patten, William D; Elzamzamy, Osama M; Attaallah, Ahmed Fikry

    2016-02-01

    Neurogenic stunned myocardium (NSM) is syndrome of myocardial dysfunction following an acute neurological insult. We report a case of NSM that occurred intraoperatively in a pediatric patient undergoing endoscopic fenestration and shunt revision. Accidental outflow occlusion of irrigation fluid and ventricular distension resulted in an acute increase in heart rate and arterial blood pressure. Subsequently, the patient developed stunned myocardium with global myocardial hypokinesia and pulmonary edema. She was promptly treated intraoperatively then admitted to the pediatric intensive care unit with resolution of her symptoms within 12 h. She was later discharged to home on the fourth postoperative day. In the current endoscopic era, this report highlights the possibility of intraoperative NSM and neurogenic pulmonary edema in the pediatric population. Early detection and treatment with a team approach help to achieve optimal control of this life-threatening condition and improve the outcome. PMID:26314948

  9. Use of a stop-flow programmable shunt valve to maximize CNS chemotherapy delivery in a pediatric patient with acute lymphoblastic leukemia

    Sheri K Palejwala

    2014-01-01

    Full Text Available Background: The requirement for frequent intraventricular drug delivery in the setting of shunt dependence is particularly challenging in the treatment of central nervous system infection, neoplastic disease, and hemorrhage. This is especially relevant in the pediatric population where both hematogenous malignancy requiring intrathecal drug delivery and shunt-dependent hydrocephalus are more prevalent. Intrathecal and intraventricular chemotherapy agents can be prematurely diverted in these shunt-dependent patients. Case Description: We report the use of a stop-flow programmable shunt valve to maximize delivery of intraventricular chemotherapy in a child with acute lymphoblastic leukemia and disseminated intravascular coagulation who presented with spontaneous intracerebral and intraventricular hemorrhages. The patient then developed posthemorrhagic hydrocephalus and eventually progressed to shunt dependence but still required frequent intraventricular chemotherapy administration. A ventriculoperitoneal shunt, equipped with a valve that allows for near cessation of cerebrospinal fluid flow (Certas; , Codman, Raynham, MA, and a contralateral Ommaya reservoir were inserted to maximize intraventricular dissemination of chemotherapy. Conclusions: To the best of our knowledge, this is the first reported case of the use of a high-resistance programmable valve being used to virtually cease cerebrospinal fluid flow through the distal catheter temporarily in order to maximize intraventricular drug dissemination in a pediatric patient with acute lymphoblastic leukemia.

  10. Transjugular Intrahepatic Portosystemic Shunt, Mechanical Aspiration Thrombectomy, and Direct Thrombolysis in the Treatment of Acute Portal and Superior Mesenteric Vein Thrombosis

    A patient was admitted because of severe abdominal pain, anorexia, and intestinal bleeding. Contrast-enhanced multidetector computed tomography demonstrated acute portal and superior mesenteric vein thrombosis (PSMVT). The patient was treated percutaneously with transjugular intrahepatic portosystemic shunt (TIPS), mechanical aspiration thrombectomy, and direct thrombolysis, and 1 week after the procedure, complete patency of the portal and superior mesenteric veins was demonstrated. TIPS, mechanical aspiration thrombectomy, and direct thrombolysis together are promising endovascular techniques for the treatment of symptomatic acute PSMVT

  11. Factors affecting ventriculoperitoneal shunt survival in adult patients

    Farid Khan

    2015-01-01

    Conclusions: Patients with increased age, prolonged hospital stay, GCS score of less than 13, extra-ventricular drains in situ, or excision of brain tumors were more likely to experience early shunt malfunction.

  12. On malfunctioning software

    Floridi, Luciano; Fresco, Nir; Primiero, Giuseppe

    2015-01-01

    Artefacts do not always do what they are supposed to, due to a variety of reasons, including manufacturing problems, poor maintenance, and normal wear-and-tear. Since software is an artefact, it should be subject to malfunctioning in the same sense in which other artefacts can malfunction. Yet, whether software is on a par with other artefacts when it comes to malfunctioning crucially depends on the abstraction used in the analysis. We distinguish between “negative” and “positive” notions of ...

  13. Ventriculoperitoneal shunt infections

    Sarguna P

    2006-01-01

    Full Text Available Central nervous system (CNS shunt infection is a cause of significant morbidity, causing shunt malfunction and chronic ill health. This study was carried out to evaluate the infection rate associated with CNS shunts, assess the frequency of the pathogens as well as their antibiotic sensitivity pattern aiming at suitable prophylaxis. A retrospective analysis of 226 CSF cerebrospinal fluid (CSF shunt procedures sent for bacteriological work up over a period of one year and six months was undertaken. Laboratory diagnosis was established by subjecting the CSF to cell count, biochemical tests, bacteriological culture and antibiotic susceptibility test. Nine out of 226(3.98% of the CSF samples were culture positive. Coagulase negative Staphylococcus was the most common isolate accounting for 36.36%. Majority of the isolates were sensitive to the thirdgeneration cephalosporins and quinolones. The antibiotic sensitivity pattern suggests cephalosporins and quinolones to be a better choice of antibiotics either prophylactically or therapeutically, which may result in effective and rapid sterilisation of the CSF.

  14. Spontaneous knot; a rare cause of ventriculoperitoneal shunt blockage.

    Mohammed, Wail

    2012-02-01

    A 14-year old X linked congenital hydrocephalus presented with unexplained headaches and vomiting. He had external ventricular drain and intracranial pressure monitoring (ICP). Subsequently, he underwent exploration and removal of previously inserted ventriculoperitoneal (VP) shunts. On retrieval of peritoneal catheters a double knot was noted between his two distal catheters. This case illustrates a rare cause of ventriculoperitoneal shunt malfunction.

  15. Spontaneous knot; a rare cause of ventriculoperitoneal shunt blockage.

    Mohammed, Wail

    2011-02-01

    A 14-year old X linked congenital hydrocephalus presented with unexplained headaches and vomiting. He had external ventricular drain and intracranial pressure monitoring (ICP). Subsequently, he underwent exploration and removal of previously inserted ventriculoperitoneal (VP) shunts. On retrieval of peritoneal catheters a double knot was noted between his two distal catheters. This case illustrates a rare cause of ventriculoperitoneal shunt malfunction.

  16. Hemi-Fontan or Bidirectional Cavopulmonary Shunt for Right Ventricular Failure after Mitral Valve Replacement and Acute Ascending Aortic Dissection: Report of Two Cases

    Hassan Teimouri

    2015-10-01

    Full Text Available Right ventricular failure due to right coronary artery disease, right ventricular hypertrophy, stunning, abnormal septal motion, myocardial infarction, or non-homogeneous distribution of cardioplegia is an uncommon but serious complication of open heart surgery. We report a patient with severe right ventricular hypertrophy secondary to severe mitral valve stenosis and another patient with detachment of the right coronary artery due to the dissection of the ascending aorta. The patients developed right ventricular failure, which persisted after surgery and rendered weaning from cardiopulmonary bypass unsuccessful. Through a hemi-Fontan, or bidirectional cavopulmonary shunt, and an intra-aortic balloon pump, the patients were successfully weaned from cardiopulmonary bypass. This shunt may be an alternative to a right ventricular assist device in some patients with right ventricular failure. The long-term outcome and the indication of bi-directional cavopulmonary shunt has not been confirmed, although it is believed to be effective for saving the life of patients with low cardiac output and acute right ventricular failure. In our cases, six months following the operation, there was some degree of recovery of the right ventricular function. In long-term follow-up, however, it would be interesting for the authors to know if the improved right ventricular function, with better antegrade pulsatile flow in the pulmonary artery, in any way interferes with the functioning of the bidirectional cavopulmonary shunt.

  17. Ventriculoperitoneal shunt

    ... belly. A small hole is drilled in the skull. A thin tube called a catheter is passed ... of ventriculoperitoneal shunt. In: Jandial R, McCormick PC, Black PM, eds. Core Techniques in Operative Neurosurgery . Philadelphia, ...

  18. Critical ventriculo-peritoneal shunt failure due to peritoneal tuberculosis: Case report and diagnostic suggestions for abdominal pseudocyst

    Hajime Takase

    2014-01-01

    Full Text Available Background: Tuberculous peritonitis (TBP is a well-known complication of ventriculo-peritoneal (VP shunt treatment for hydrocephalus resulting from tuberculous meningitis (TBM. However, a case of hydrocephalus unrelated to TBM resulting from VP shunt malfunction due to TBP has not been reported. Case Description: A 21-year-old male presented with nausea, abdominal pain, and headache. VP and cysto-peritoneal (CP shunts had been inserted to treat hydrocephalus due to a suprasellar arachnoid cyst, replaced the VP and removed the CP in his childhood. Computed tomography demonstrated acute hydrocephalus and an abdominal pseudocyst surrounding the distal end of the peritoneal tube. Initial laboratory data showed elevated white blood cell count and C-reactive protein level, but no causative pathogen was identified. External drainage of cerebrospinal fluid (CSF and of the fluid in the peritoneal cyst was established, and empirical antibiotic therapy was initiated. Bacterial cultures eventually revealed Mycobacterium tuberculosis infection, and TBP was diagnosed. The patient responded well to antituberculosis (anti-TB agents and insertion of a ventriculo-pleural shunt. Conclusion: This case highlights the possibility of CSF shunt failure and concomitant neurological sequelae from TB infection even when the pathogen has not invaded the central nervous system, as in TBM. Moreover, TBP is rare in developed countries and therefore may be misdiagnosed because of nonspecific clinical features and low sensitivity of common TB screening methods.

  19. Acute effects of liver vein occlusion by stent-graft placed in transjugular intrahepatic portosystemic shunt channel: An experimental study

    Keussen, Inger; Bergqvist, Lennart; Rissler, Pehr; Cwikiel, W

    2006-01-01

    The purpose of this study was to evaluate the effects of hepatic vein occlusion by stent-graft used in transjugular intrahepatic portosystemic shunt (TIPS). The experiments were performed in six healthy pigs under general anesthesia. Following percutaneous transhepatic implantation of a port-a-cath in the right hepatic vein, TIPS was created with a stent-graft (Viatorr; W L Gore, Flagstaff, AZ, USA). The outflow from the hepatic vein, blocked by the stent-graft was documented by injection of ...

  20. Transjugular intrahepatic portosystemic shunt.

    Ochs, Andreas

    2005-01-01

    The transjugular intrahepatic portosystemic shunt (TIPS) is an interventional treatment resulting in decompression of the portal system by creation of a side-to-side portosystemic anastomosis. Since its introduction 16 years ago, more than 1,000 publications have appeared demonstrating broad acceptance and increasing clinical use. This review summarizes our present knowledge about technical aspects and complications, follow-up of patients and indications. A technical success rate near 100% and a low occurrence of complications clearly depend on the skills of the operator. The follow-up of the TIPS patient has to assess shunt patency, liver function, hepatic encephalopathy and the possible development of hepatocellular carcinoma. Shunt patency can best be monitored by duplex sonography and can avoid routine radiological revision. Short-term patency may be improved by anticoagulation, while such a treatment does not influence long-term patency. Stent grafts covered with expanded polytetrafluoroethylene show promising long-term patency comparable with that of surgical shunts. With respect to the indications of TIPS, much is known about treatment of variceal bleeding and refractory ascites. The thirteen randomized studies that are available to date show that survival is comparable in patients receiving TIPS or endoscopic treatment for acute or recurrent variceal bleeding. Another group comprises patients with refractory ascites and related complications, such as hepatorenal syndrome and hepatic hydrothorax. It has been demonstrated that TIPS improves these complications. Five randomized studies comparing TIPS with paracentesis and one study comparing TIPS with the peritoneo-venous shunt showed good response of ascites but controversial results on survival. In addition, TIPS has been successfully applied to patients with Budd-Chiari syndrome, portal vein thrombosis, before liver transplantation, and for the treatment of ectopic variceal bleeding. PMID:15920326

  1. Transjugular Intrahepatic Portosystemic Shunt (TIPS): Current Status and Future Possibilities

    Since the insertion of the first TIPS in 1989 much has been learned about this therapeutic procedure. It has an established role for the treatment of some complications of portal hypertension: prevention of recurrent variceal bleeding and rescue of patients with acute uncontrollable variceal bleeding. In addition TIPS is useful for Budd-Chiari syndrome, refractory ascites and hepatorenal syndrome, although its specific role in these indications remains to be definitively established. However, the decrease in sinusoidal blood flow induced by TIPS can lead to the patient developing hepatic encephalopathy and liver failure in some cases. Therefore, TIPS should be used with caution in patients with very poor liver function. From a technical point of view, successful placement of TIPS is achieved in more than 98% of cases by experienced groups. At present, evaluation of TIPS dysfunction based on morphology probably leads to an overdiagnosis of this complication since most of these cases are not associated with clinical manifestations (recurrent bleeding or refractory ascites). The major disadvantage of TIPS remains its poor long-term patency requiring a mandatory surveillance program. The indicator for shunt function/malfunction should be the portosystemic pressure gradient, which is best assessed by intravascular measurements. Shunt obstructions may be prevented or reduced by the use of stent-grafts in the future

  2. Complications of Denver Shunt

    Eranga Perera; Shweta Bhatt; Vikram S Dogra

    2011-01-01

    Hepatic hydrothorax secondary to transdiaphragmatic spread of peritoneal fluid can cause respiratory discomfort to the patient. Draining of hydrothorax helps relieve these symptoms. Pleurovenous shunt (Denver shunt) is a relatively non-invasive method of shunting the pleural fluid to the central venous system. Reported complications of pleurovenous shunts are shunt failure, pulmonary edema, post shunt coagulopathy, deep vein thrombosis, and infection. We report a rare case of a leak at the ve...

  3. A new logic of technical malfunction

    Jespersen, Bjørn; Carrara, Massimiliano

    2013-01-01

    Aim of the paper is to present a new logic of technical malfunction. The need for this logic is motivated by a simple-sounding philosophical question: Is a malfunctioning corkscrew, which fails to uncork bottles, nonetheless a corkscrew? Or in general terms, is a malfunctioning F, which fails to do what Fs do, nonetheless an F? We argue that ‘malfunctioning’ denotes the modifier Malfunctioning rather than a property, and that the answer depends on whether Malfunctioning is subsective or priva...

  4. Acute Effects of Liver Vein Occlusion by Stent-Graft Placed in Transjugular Intrahepatic Portosystemic Shunt Channel: An Experimental Study

    The purpose of this study was to evaluate the effects of hepatic vein occlusion by stent-graft used in transjugular intrahepatic portosystemic shunt (TIPS). The experiments were performed in six healthy pigs under general anesthesia. Following percutaneous transhepatic implantation of a port-a-cath in the right hepatic vein, TIPS was created with a stent-graft (Viatorr; W L Gore, Flagstaff, AZ, USA). The outflow from the hepatic vein, blocked by the stent-graft was documented by injection of contrast medium and repeated injections of 99Tcm-labeled human serum albumin through the port-a-cath. After 2 weeks, the outflow was re-evaluated, the pigs were sacrificed, and histopathologic examination of the liver was performed. Occlusion of the hepatic vein by a stent-graft had a short and temporary effect on the outflow. Histopathological examination from the affected liver segment showed no divergent pattern. Stent-grafts used in TIPS block the outflow from the liver vein, but do not have a prolonged circulatory effect and do not affect the liver parenchyma

  5. Symptomatic spinal cord deformity secondary to a redundant intramedullary shunt catheter

    Right arm pain, motor and sensory loss in the right arm and right facial numbness recurred in a 27 year old quadraplegic shortly after a posttraumatic spinal cord cyst (PTSCC) was shunted via a catheter into the adjacent subarachnoid space. Although shunt malfunction was clinically suspected, metrizamide computed tomography (MCT) suggested that redundancy of the catheter had caused deformity of the spinal cord. This hypothesis was confirmed at surgery when intraoperative spinal sonography (IOSS) showed that the spinal cord deformity at C1-C2 disappeared when the catheter was withdrawn. This case shows that new or recurrent spinal cord symptoms may be due to a mechanical deformity of the cord rather than shunt malfunction, that restricting the length of the shunt catheter which is used to decompress PTSCCs is important, and that IOSS is an indispensible tool for visualizing the changes in spinal cord morphology during shunting procedures. (orig.)

  6. Complications of Denver Shunt

    Eranga Perera

    2011-01-01

    Full Text Available Hepatic hydrothorax secondary to transdiaphragmatic spread of peritoneal fluid can cause respiratory discomfort to the patient. Draining of hydrothorax helps relieve these symptoms. Pleurovenous shunt (Denver shunt is a relatively non-invasive method of shunting the pleural fluid to the central venous system. Reported complications of pleurovenous shunts are shunt failure, pulmonary edema, post shunt coagulopathy, deep vein thrombosis, and infection. We report a rare case of a leak at the venous end of the catheter that was placed within the right internal jugular vein, resulting in a large collection in the neck.

  7. Distal splenorenal shunt

    ... Surg. 2006 Apr;141(4):385-8. J. Michael Henderson JM, Boyer TD, Kutner MH, et al. Distal splenorenal shunt versus transjugular intrahepatic portal systematic shunt for variceal bleeding: a randomized trial. ...

  8. The presence of a right-to-left shunt is associated with dramatic improvement after thrombolytic therapy in acute ischemic stroke patients

    The efficacy of pharmacological thrombolysis using tissue plasminogen activator (t-PA) depends upon the relative fibrin content of the thrombus. We investigated whether stroke patients with a right-to-left shunt (RLS), whose embolic source was associated with fibrin-rich thrombus formed in the venous system, were more likely to improve dramatically after thrombolytic therapy than those without RLS. Acute stroke patients treated with t-PA were assessed prospectively to determine the clinical factors associated with ''dramatic improvement'' after t-PA administration. ''dramatic improvement'' was defined as a ≥10 point reduction in the total National Institutes of Health Stroke Scale (NIHSS) score or a total NIHSS score of 0 or 1 at 7 days. The presence of an RLS was determined using contrast transcranial Doppler (c-TCD) within 6 hours of stroke onset. Forty eight patients (26 males; mean age: 73.0±10.7 years; baseline NIHSS score, 13.4±6.6) were enrolled. Twenty-one patients had dramatic improvement (D group). c-TCD demonstrated an RLS in 17 (35.4%) patients. On multivariate logistic regression analysis using hyperlipidemia, atrial fibrillation, RLS, diffusion-weighted imaging (DWI)-Alberta Stroke Programme Early CT Score (ASPECTS) (>8), baseline NIHSS score (<10), and glucose (<120 mg/dl) as variables with a P<0.1 on univariate analysis, RLS (odds ratio (OR): 5.9; confidence interval (CI): 1.3-27.3, P=0.022) was the only independent factor associated with dramatic improvement. The presence of an RLS on c-TCD was an independent factor associated with dramatic improvement after t-PA administration. (author)

  9. Urethral protrusion of the abdominal catheter of ventriculoperitoneal shunt: Case report of extremely rare complication

    Ugur Yazar

    2012-01-01

    Full Text Available Hydrocephalus in its various forms constitutes one of the major problems in pediatric neurosurgical practice. The placement of a ventriculoperitoneal (VP shunt is the most common form of treatment for hydrocephalus, so that all neurosurgeons struggle with shunt malfunctions and their complications. Well-known complications are connected with the use of the valve systems (malfunction, infectious, overdrainage, secondary craniosynostosis, etc.. We report an unusual case of protruding abdominal catheter from the urethra. This girl had received a VP shunt for hydrocephalus following surgery of posterior fossa medulloblastoma 4 years ago. After admission, the entire system was removed, antibiotic treatment was administered for 2 weeks, and a new VP shunt was placed. The postoperative course was uneventful. This complication is extremely rare.

  10. Parylene MEMS patency sensor for assessment of hydrocephalus shunt obstruction.

    Kim, Brian J; Jin, Willa; Baldwin, Alexander; Yu, Lawrence; Christian, Eisha; Krieger, Mark D; McComb, J Gordon; Meng, Ellis

    2016-10-01

    Neurosurgical ventricular shunts inserted to treat hydrocephalus experience a cumulative failure rate of 80 % over 12 years; obstruction is responsible for most failures with a majority occurring at the proximal catheter. Current diagnosis of shunt malfunction is imprecise and involves neuroimaging studies and shunt tapping, an invasive measurement of intracranial pressure and shunt patency. These patients often present emergently and a delay in care has dire consequences. A microelectromechanical systems (MEMS) patency sensor was developed to enable direct and quantitative tracking of shunt patency in order to detect proximal shunt occlusion prior to the development of clinical symptoms thereby avoiding delays in treatment. The sensor was fabricated on a flexible polymer substrate to eventually allow integration into a shunt. In this study, the sensor was packaged for use with external ventricular drainage systems for clinical validation. Insights into the transduction mechanism of the sensor were obtained. The impact of electrode size, clinically relevant temperatures and flows, and hydrogen peroxide (H2O2) plasma sterilization on sensor function were evaluated. Sensor performance in the presence of static and dynamic obstruction was demonstrated using 3 different models of obstruction. Electrode size was found to have a minimal effect on sensor performance and increased temperature and flow resulted in a slight decrease in the baseline impedance due to an increase in ionic mobility. However, sensor response did not vary within clinically relevant temperature and flow ranges. H2O2 plasma sterilization also had no effect on sensor performance. This low power and simple format sensor was developed with the intention of future integration into shunts for wireless monitoring of shunt state and more importantly, a more accurate and timely diagnosis of shunt failure. PMID:27589973

  11. Early onset tension pneumocephalus following ventriculoperitoneal shunt insertion for normal pressure hydrocephalus: a case report.

    Barada, Wissam; Najjar, Marwan; Beydoun, Ahmad

    2009-04-01

    The occurrence of tension pneumocephalus following ventriculoperitoneal (v.p.) shunt insertion is extremely rare, and is usually of delayed onset. We report a patient who developed an acute subdural tension pneumocephalus within 1 day following placement of a v.p. shunt for normal pressure hydrocephalus as a complication from shunt surgery. PMID:19185417

  12. Endoscopic Third Ventriculostomy in Previously Shunted Children

    Eva Brichtova

    2013-01-01

    Full Text Available Endoscopic third ventriculostomy (ETV is a routine and safe procedure for therapy of obstructive hydrocephalus. The aim of our study is to evaluate ETV success rate in therapy of obstructive hydrocephalus in pediatric patients formerly treated by ventriculoperitoneal (V-P shunt implantation. From 2001 till 2011, ETV was performed in 42 patients with former V-P drainage implantation. In all patients, the obstruction in aqueduct or outflow parts of the fourth ventricle was proved by MRI. During the surgery, V-P shunt was clipped and ETV was performed. In case of favourable clinical state and MRI functional stoma, the V-P shunt has been removed 3 months after ETV. These patients with V-P shunt possible removing were evaluated as successful. In our group of 42 patients we were successful in 29 patients (69%. There were two serious complications (4.7%—one patient died 2.5 years and one patient died 1 year after surgery in consequence of delayed ETV failure. ETV is the method of choice in obstructive hydrocephalus even in patients with former V-P shunt implantation. In case of acute or scheduled V-P shunt surgical revision, MRI is feasible, and if ventricular system obstruction is diagnosed, the hydrocephalus may be solved endoscopically.

  13. Lumbar peritoneal shunt

    Yadav Yad

    2010-01-01

    Full Text Available A lumbar peritoneal (LP shunt is a technique of cerebrospinal fluid (CSF diversion from the lumbar thecal sac to the peritoneal cavity. It is indicated under a large number of conditions such as communicating hydrocephalus, idiopathic intracranial hypertension, normal pressure hydrocephalus, spinal and cranial CSF leaks, pseudomeningoceles, slit ventricle syndrome, growing skull fractures which are difficult to treat by conventional methods (when dural defect extends deep in the cranial base or across venous sinuses and in recurrent cases after conventional surgery, raised intracranial pressure following chronic meningitis, persistent bulging of craniotomy site after operations for intracranial tumors or head trauma, syringomyelia and failed endoscopic third ventriculostomy with a patent stoma. In spite of the large number of indications of this shunt and being reasonably good, safe, and effective, very few reports about the LP shunt exist in the literature. This procedure did not get its due importance due to some initial negative reports. This review article is based on search on Google and PubMed. This article is aimed to review indications, complications, results, and comparison of the LP shunt with the commonly practiced ventriculoperitoneal (VP shunt. Shunt blocks, infections, CSF leaks, overdrainage and acquired Chiari malformation (ACM are some of the complications of the LP shunt. Early diagnosis of overdrainage complications and ACM as well as timely appropriate treatment especially by programmable shunts could decrease morbidity. Majority of recent reports suggest that a LP shunt is a better alternative to the VP shunt in communicating hydrocephalus. It has an advantage over the VP shunt of being completely extracranial and can be used under conditions other than hydrocephalus when the ventricles are normal sized or chinked. More publications are required to establish its usefulness in the treatment of wide variety of indications.

  14. The peritoneo-venous shunts of Le Veen and the testing of its function

    A radio technique for testing the patency of, peritoneo-venous shunts of Le Veen, is reported and is demonstrated by discussing a case history. By now a total number of 16 patients have been tested, after implantation of such a shunt. The demonstrated radioisotope technique, which causes no complaints from the patient, is not only able to inform concerning the functional state of the Le Veen shunts, but also, in case of disturbances, is able to reveal the cause of the underlying malfunctions. (author)

  15. Exit ventriculoperitoneal shunt; enter endoscopic third ventriculostomy (ETV): contemporary views on hydrocephalus and their implications on management

    Kamalo, P

    2013-01-01

    Hydrocephalus has been known to affect humans since the birth of human medicine as it is described by Hippocrates. The management of this condition is however still dodged by challenges due to a poor understanding of its pathophysiology. The ventriculoperitoneal shunt presents considerable problems especially with respect to infection and shunt malfunction. Low income countries, that currently face the greater burden of paediatric hydrocephalus. experience an increased challenge with ventricu...

  16. Shunt tube calcification as a late complication of ventriculoperitoneal shunting.

    Salim, Abubakr Darrag; Elzain, Mohammed Awad; Mohamed, Haddab Ahmed; Ibrahim Zayan, Baha Eldin Mohamed

    2015-01-01

    Shunt calcification is a rare complication of ventriculoperitoneal shunting that occurs years later after the initial operation this condition is rarely reported in literature. Two patients with shunt calcifications were described. The first patient was 17-year-old lady who had congenital hydrocephalus and shunted in the early infancy, she was presented recently complaining of itching of the skin along the shunt track and limitation of neck movement. The patient was then operated with removal of the old peritoneal catheter and replacing it with a new one. The second patient was 17-year-old boy originally was a case of posterior fossa pilocytic astrocytoma associated with obstructive hydrocephalus, he was operated with both shunting for the hydrocephalus and tumor removal, 6 years later he presented with shunt exposure. Calcification of the shunt tube was discovered intraoperatively upon shunt removal. Shunt calcification has been observed mainly in barium-impregnated catheters. Introducing plain silicone-coated shunt tubing may reduce the rate of this condition. The usual complaints of the patients suffering from this condition are pain in the neck and chest wall along the shunt pathway and limitation of the neck movement due to shunt tube tethering, but features of shunt dysfunction and skin irritation above the shunt may be present. In this review, plain X-ray and operative findings showed that the most extensive calcification is present in the neck, where the catheters were subject to heavy mechanical stress. Disturbed calcium and phosphate metabolisms may be involved in this condition. Shunt calcification is a rare condition that occurs due to material aging presenting with features of shunt tethering, dysfunction or overlying skin irritation. Plain X-ray is needed to detect calcification while shunt removal, replacement or endoscopic third ventriculostomy may carry solution for this condition. PMID:26396620

  17. Two Episodes of Ventriculoperitoneal Shunt Migration in a Patient with Idiopathic Intracranial Hypertension

    V. Balakrishnan

    2014-01-01

    Full Text Available Introduction. Ventriculoperitoneal shunts are often placed as treatment for refractory idiopathic intracranial hypertension. Dislodgement and migration of the distal portion of the shunt are more common in obese patients and can be difficult to detect. We report the case of a woman with two separate episodes of shunt migration into her abdominal wall. Case Presentation. We report a case of a 37-year-old female with history of obesity eventually diagnosed with idiopathic intracranial hypertension (IIH as the cause. She failed outpatient therapy and, through neurosurgery, had a VP shunt placed for symptom control. She had subsequent development of worsened symptoms that were found to be due to shunt migration. This happened not once but twice to the same patient. Conclusion. Shunt dislodgement, migration, and subsequent failure are common in obese patients who have shunts placed for IIH. The medical provider should maintain a high index of suspicion for shunt malfunction in these patients, particularly because clinical evaluation may be challenging due to habitus.

  18. Imaging of the ventriculoperitoneal shunt-related complications in infants and children with hydrocephalus

    To evaluate the frequency and imaging findings of various ventriculo-peritoneal shunt-related complications in pediatric patients with hydrocephalus. We retrospectively reviewed 246 plain radiographs, three shuntograms, 53 ultrasounds, 133 CT scans, and 24 MR images obtained before and after the ventriculo-peritoneal shunt procedure in 33 pediatric patients with hydrocephalus. Using preoperative images, the etiology of the hydrocephalus was assessed. Changes in the size and shape of the ventricles, the location and continuity of shunt apparatus, and the presence of any abnormal enhancement, hemorrhage, edema or tissue loss, or other findings of complications, were analyzed on postoperative images ; the frequency and imaging findings of shunt-related complications such as shunt malfunction, infection, homorrhage or isolated ventricle, and complications caused by overdrainage, were thus evaluated. The frequency of such complications was analyzed according to the etiology of the hydrocephalus, and in addition, medical records were reviewed and correlated with imaging findings. In 18 of the 33 patients(54%), a total of 31 complications was detected. These were present in four of five cases (80%) of hydrocephalus caused by meningitis and ventriculitis, seven of twelve (58%) intraventricular hemorrhage, two of four (50%) unknown cases, three of nine (33%) congenital malformations, one of two (50%) tumors, and one (100%) congenital infection. Shunt malfunction was most common (n=15), and was accompanied by findings of enlarged ventricles, periventricular and peritubal edema, and abnormal location of the shunt tube. Symptoms and signs of increased intracranial pressure were also noted. Subdural hemorrhage and infection were present in four cases each ; findings of infection were enhancement of the ventricular wall, meninges, and parenchyma, as well as sonographically noted intraventricular septation and increased ventricular wall echo. Isolated lateral ventricle (n=4) or 4

  19. Neurocomputational Nosology: Malfunctions of Models and Mechanisms

    Barack, David L.; Platt, Michael L.

    2016-01-01

    Executive dysfunctions, psychopathologies arising from problems in the control and regulation of behavior, can occur as a result of the faulty execution of formal information processing models or as a result of malfunctioning neural mechanisms. The models correspond to the formal descriptions of how signals in the environment must be transformed in order to behave adaptively, and the mechanisms correspond to the signal transformations that nervous systems implement in order to execute those cognitive functions. Mechanisms in the form of repeated patterns of neural dynamics execute information processing models. Two distinct modes of malfunction can occur when neural dynamics execute models of information processing. The processing models describing behavior may fail to be executed correctly by neural mechanisms. Or, the neural mechanisms may malfunction, failing to implement the right computation. As an example of malfunctioning models in executive cognition, purported failures of rule following can be understood as failures to appropriately execute a suite of processing models. As an example of malfunctioning mechanisms of executive cognition, maladaptive behavior resulting from dysfunction in the medial prefrontal cortex (mPFC) can be understood as failures in the signal transformations carried out therein. The purpose of these examples is to illustrate the potential benefits of considering models and mechanisms in the diagnosis and etiology of neuropsychological illness and dysfunction, especially disorders of executive cognition. PMID:27199835

  20. Neurocomputational Nosology: Malfunctions of Models and Mechanisms

    David L Barack

    2016-05-01

    Full Text Available Executive dysfunctions, psychopathologies arising from problems in the control and regulation of behavior, can occur as a result of the faulty execution of formal information processing models or as a result of malfunctioning neural mechanisms. The models correspond to the formal descriptions of how signals in the environment must be transformed in order to behave adaptively, and the mechanisms correspond to the signal transformations that nervous systems implement in order to execute those cognitive functions. Mechanisms in the form of repeated patterns of neural dynamics execute information processing models. Two distinct modes of malfunction can occur when neural dynamics execute models of information processing. The processing models describing behavior may fail to be executed correctly by neural mechanisms. Or, the neural mechanisms may malfunction, failing to implement the right computation. As an example of malfunctioning models in executive cognition, purported failures of rule following can be understood as failures to appropriately execute a suite of processing models. As an example of malfunctioning mechanisms of executive cognition, maladaptive behavior resulting from dysfunction in the medial prefrontal cortex can be understood as failures in the signal transformations carried out therein. The purpose of these examples is to illustrate the potential benefits of considering models and mechanisms in the diagnosis and etiology of neuropsychological illness and dysfunction, especially disorders of executive cognition.

  1. Neurocomputational Nosology: Malfunctions of Models and Mechanisms.

    Barack, David L; Platt, Michael L

    2016-01-01

    Executive dysfunctions, psychopathologies arising from problems in the control and regulation of behavior, can occur as a result of the faulty execution of formal information processing models or as a result of malfunctioning neural mechanisms. The models correspond to the formal descriptions of how signals in the environment must be transformed in order to behave adaptively, and the mechanisms correspond to the signal transformations that nervous systems implement in order to execute those cognitive functions. Mechanisms in the form of repeated patterns of neural dynamics execute information processing models. Two distinct modes of malfunction can occur when neural dynamics execute models of information processing. The processing models describing behavior may fail to be executed correctly by neural mechanisms. Or, the neural mechanisms may malfunction, failing to implement the right computation. As an example of malfunctioning models in executive cognition, purported failures of rule following can be understood as failures to appropriately execute a suite of processing models. As an example of malfunctioning mechanisms of executive cognition, maladaptive behavior resulting from dysfunction in the medial prefrontal cortex (mPFC) can be understood as failures in the signal transformations carried out therein. The purpose of these examples is to illustrate the potential benefits of considering models and mechanisms in the diagnosis and etiology of neuropsychological illness and dysfunction, especially disorders of executive cognition. PMID:27199835

  2. A New Logic of Technical Malfunction

    Jespersen, Bjorn; Carrara, M.

    2013-01-01

    Roč. 101, č. 3 (2013), s. 547-581. ISSN 0039-3215 Institutional support: RVO:67985955 Keywords : logic of malfunction * modification * simple type theory * transparent intensional logic * philosophy of technology * artefact * functioning as * intensional essentialism Subject RIV: AA - Philosophy ; Religion Impact factor: 0.330, year: 2013

  3. 40 CFR 63.1272 - Startups, shutdowns, and malfunctions.

    2010-07-01

    ... 40 Protection of Environment 11 2010-07-01 2010-07-01 true Startups, shutdowns, and malfunctions... Facilities § 63.1272 Startups, shutdowns, and malfunctions. (a) The provisions set forth in this subpart shall apply at all times except during startups or shutdowns, during malfunctions, and during periods...

  4. 40 CFR 63.1111 - Startup, shutdown, and malfunction.

    2010-07-01

    ... 40 Protection of Environment 10 2010-07-01 2010-07-01 false Startup, shutdown, and malfunction. 63... Control Technology Standards § 63.1111 Startup, shutdown, and malfunction. (a) Startup, shutdown, and... develop a written startup, shutdown, and malfunction plan that describes, in detail, procedures...

  5. 40 CFR 63.762 - Startups, shutdowns, and malfunctions.

    2010-07-01

    ... 40 Protection of Environment 10 2010-07-01 2010-07-01 false Startups, shutdowns, and malfunctions... Facilities § 63.762 Startups, shutdowns, and malfunctions. (a) The provisions set forth in this subpart shall apply at all times except during startups or shutdowns, during malfunctions, and during periods of...

  6. Neurocomputational Nosology: Malfunctions of Models and Mechanisms

    Barack, David L.; Platt, Michael L.

    2016-01-01

    Executive dysfunctions, psychopathologies arising from problems in the control and regulation of behavior, can occur as a result of the faulty execution of formal information processing models or as a result of malfunctioning neural mechanisms. The models correspond to the formal descriptions of how signals in the environment must be transformed in order to behave adaptively, and the mechanisms correspond to the signal transformations that nervous systems implement in order to execute those c...

  7. Transjugular Intrahepatic Portosystemic Shunt (TIPS)

    Full Text Available Toggle navigation Test/Treatment Patient Type Screening/Wellness Disease/Condition Safety En Español More Info Images/Videos News Physician Resources Professions Site Index A-Z Transjugular Intrahepatic Portosystemic Shunt (TIPS) Transjugular Intrahepatic Portosystemic Shunt or TIPS is a procedure ...

  8. Congenital extrahepatic portosystemic shunts

    Murray, Conor P.; Yoo, Shi-Joon; Babyn, Paul S. [Department of Diagnostic Imaging, Hospital for Sick Children, 555 University Avenue, M5G 1X8, Toronto, Ontario (Canada)

    2003-09-01

    A congenital extrahepatic portosystemic shunt (CEPS) is uncommon. A type 1 CEPS exists where there is absence of intrahepatic portal venous supply and a type 2 CEPS where this supply is preserved. The diagnosis of congenital portosystemic shunt is important because it may cause hepatic encephalopathy. To describe the clinical and imaging features of three children with CEPS and to review the cases in the published literature. The diagnostic imaging and medical records for three children with CEPS were retrieved and evaluated. An extensive literature search was performed. Including our cases, there are 61 reported cases of CEPS, 39 type 1 and 22 type 2. Type 1 occurs predominantly in females, while type 2 shows no significant sexual preponderance. The age at diagnosis ranges from 31 weeks of intrauterine life to 76 years. Both types of CEPS have a number of associations, the most common being nodular lesions of the liver (n=25), cardiac anomalies (n=19), portosystemic encephalopathy (n=10), polysplenia (n=9), biliary atresia (n=7), skeletal anomalies (n=5), and renal tract anomalies (n=4). MRI is recommended as an important means of diagnosing and classifying cases of CEPS and examining the associated cardiovascular and hepatic abnormalities. Screening for CEPS in patients born with polysplenia is suggested. (orig.)

  9. Outcome analysis of shunt surgery in hydrocephalus

    Ahmed Ashraf

    2009-01-01

    Full Text Available Aim: To study the clinical outcome of shunt surgeries in children suffering from hydrocephalus. Methods: A prospective study of 50 children with hydrocephalus who underwent a ventriculo-peritoneal shunt insertion over a period of two years. These patients were then followed up for shunt related complications, shunt revisions and outcome. Results : Twenty six of the 50 patients (52% suffered from complications. The most common complications were shunt blockage (n=7 and shunt infection (n=6. These complications necessitated repeated shunt revisions. Conclusions: Infective complications of hydrocephalus are more likely to leave behind an adverse neurological outcome in the form of delayed milestones and mental retardation.

  10. Transjugular Intrahepatic Portosystemic Shunt (TIPS)

    Full Text Available ... anti-inflammatory drugs (NSAIDs) or blood thinners several days prior to your procedure and instructed to not ... overnight at the hospital for one or more days. What is Transjugular Intrahepatic Portosystemic Shunt (TIPS)? What ...

  11. Quadrupole shunt experiments at SPEAR

    As part of a program to align and stabilize the SPEAR storage ring, a switchable shunt resistor was installed on each quadrupole to bypass a small percentage of the magnet current. The impact of a quadrupole shunt is to move the electron beam orbit in proportion to the off-axis beam position at the quadrupole and to shift the betatron tune. Initially, quadrupole shunts in SPEAR were used to position the electron beam in the center of the quadrupoles. This provided readback offsets for nearby beam position monitors and helped to steer the photon beams with low-amplitude corrector currents. The shunt-induced tune shift measurements were then processed in MAD to derive a lattice model. copyright 1997 American Institute of Physics

  12. Transjugular Intrahepatic Portosystemic Shunt (TIPS)

    Full Text Available ... Shunt or TIPS is a procedure that uses imaging guidance to connect the portal vein to the ... is any possibility that they are pregnant. Many imaging tests are not performed during pregnancy so as ...

  13. Transjugular Intrahepatic Portosystemic Shunt (TIPS)

    Full Text Available ... bear denotes child-specific content. Related Articles and Media Radiation Dose in X-Ray and CT Exams Contrast Materials Venography Images related to Transjugular Intrahepatic Portosystemic Shunt (TIPS) About ...

  14. Transjugular Intrahepatic Portosystemic Shunt (TIPS)

    Full Text Available ... considerations. The teddy bear denotes child-specific content. Related Articles and Media Radiation Dose in X-Ray and CT Exams Contrast Materials Venography Images related to Transjugular Intrahepatic Portosystemic Shunt (TIPS) About this ...

  15. Magnetic fields and intrathecal pump malfunction.

    Huh, Billy; Roldan, Carlos J

    2016-01-01

    Medical technology has impacted the overall life expectancy. Many conditions traditionally considered fatal are now curable. Surviving chronic diseases and aging of the population have increased the number of people with chronic pain. Many devices are also available to manage severe refractory pain. As such, implantable drug-delivery system (IDDS) is a small battery-powered, programmable pump implanted under the subcutaneous tissue of the abdomen and connected to a small catheter tunneled into the spine. Implantable drug-delivery system is used for the administration of morphine, ziconotide, baclofen, or their mixtures into the cerebrospinal fluid. Like many medical devices, IDDS has technical glitch which limits its performance under certain conditions. Implantable drug-delivery system is susceptible to magnetic field such as a magnetic resonance imaging (MRI) which can temporarily stall the rotor of the pump motor and suspend drug delivery. We encountered a patient from out of town seen at emergency department with increased pain and symptoms of opiates withdrawal after intermittent IDDS malfunction. He denied any exposure to magnetic fields or MRI. However, the pump interrogation showed multiple motor stall events in the event log. After a detailed inquiry, the most likely cause of pump malfunction appears to be frequent placement of a laptop computer on his abdomen close to the pump. The magnets in the laptop speakers may have caused the rotor of the pump motor to stall during the computer use, and frequent stall has caused symptoms of withdrawal. No other mechanical failures were found. The patient was discharged home after the symptoms resolved, and the pump was reprogrammed. PMID:26008580

  16. Anatomical Closure of Left-to-Right Shunts in Premature Infants with Bronchopulmonary Dysplasia and Pulmonary Hypertension: A Cautionary Tale

    Dereddy, Narendra R.; Chilakala, Sandeep R.; Divya Rana

    2015-01-01

    Closure of a systemic to pulmonary shunt in premature infants with bronchopulmonary dysplasia may be beneficial, but in the presence of pulmonary hypertension is controversial. Here, we discuss two premature infants with pulmonary hypertension who developed acute pulmonary hypertensive crisis after closure of these shunts and hence advise caution.

  17. Anatomical Closure of Left-to-Right Shunts in Premature Infants with Bronchopulmonary Dysplasia and Pulmonary Hypertension: A Cautionary Tale

    Narendra R. Dereddy

    2015-10-01

    Full Text Available Closure of a systemic to pulmonary shunt in premature infants with bronchopulmonary dysplasia may be beneficial, but in the presence of pulmonary hypertension is controversial. Here, we discuss two premature infants with pulmonary hypertension who developed acute pulmonary hypertensive crisis after closure of these shunts and hence advise caution.

  18. 76 FR 12743 - Medical Device Reporting; Malfunction Reporting Frequency

    2011-03-08

    ... HUMAN SERVICES Food and Drug Administration Medical Device Reporting; Malfunction Reporting Frequency... continue to submit malfunction reports in full compliance with FDA's Medical Device Reporting regulation... supporting, or life sustaining, must continue to report in full compliance with part 803, pending further...

  19. Association of Brucella Meningoencephalitis with Cerebrospinal Fluid Shunt in A Child: A Case Report

    Babak ABDINIA

    2013-01-01

    Full Text Available Brucellosis is an endemic zoonosis in Iran. It is a systemic infection that can involve any organs or systems of the body and have variable presentations. Ventriculoperitoneal (VP shunt infections due to brucellosis have been rarely reported in the literatures.This is the history of a four years old boy who developed Brucella meningoencephalitis at the age of 42 months, whilst he had a VP shunt in situ for hydrocephalus treatment. Also, he presented brucellosis as acute abdomen. This patient was treated with trimethoprim-sulfamethoxazole, gentamicin and rifampicin. The shunt was extracted and all clinical and laboratory test abnormalities subsided through this management.We propose that in a patient with Brucella meningoencephalitis, the cerebrospinal fluid shunt system can be extracted and treatment with appropriate combination of antibiotics could be successful. Moreover, it shows that brucellosis should be considered in the differential diagnosis for acute abdomen and ascites in endemic regions.

  20. Control Rod Malfunction at the NRAD Reactor

    Thomas L. Maddock

    2010-05-01

    The neutron Radiography Reactor (NRAD) is a training, research, and isotope (TRIGA) reactor located at the INL. The reactor is normally shut down by the insertion of three control rods that drop into the core when power is removed from electromagnets. During a routine shutdown, indicator lights on the console showed that one of the control rods was not inserted. It was initially thought that the indicator lights were in error because of a limit switch that was out of adjustment. Through further testing, it was determined that the control rod did not drop when the scram switch was initially pressed. The control rod anomaly led to a six month shutdown of the reactor and an in depth investigation of the reactor protective system. The investigation looked into: scram switch operation, console modifications, and control rod drive mechanisms. A number of latent issues were discovered and corrected during the investigation. The cause of the control rod malfunction was found to be a buildup of corrosion in the control rod drive mechanism. The investigation resulted in modifications to equipment, changes to both operation and maintenance procedures, and additional training. No reoccurrences of the problem have been observed since corrective actions were implemented.

  1. Candidal infections of ventriculoperitoneal shunts

    V P Baradkar

    2009-01-01

    Full Text Available Although ventriculoperitoneal (VP shunt infection is a common complication of shunt procedures, fungal infection is considered to be rare. In the present study, we performed retrospective analysis of six cases in which candida infection occurred. In all these six cases, VP shunt was performed in children for hydrocephalus and the onset of symptoms varied between seven days to one month after the surgical procedure was performed. The commonest clinical signs and symptoms were fever (100%, vomiting (100%, and altered sensorium (50%. The commonest isolate was Candida albicans (66.66% followed by Candida parapsilosis and Candida glabrata in one case each. All the patients were successfully treated with Amphotericin B and there was no mortality recorded.

  2. Orthopaedic complications of lumboperitoneal shunts.

    McIvor, J; Krajbich, J I; Hoffman, H

    1988-01-01

    Lumboperitoneal (LP) shunts performed for communicating hydrocephalus have been reported to lead to neurologic deficits in the lower limbs and spinal deformities as a result of arachnoiditis. A chart review of 375 children who underwent LP shunts between 1960 and 1981 at The Hospital For Sick Children in Toronto was undertaken. Of the 375 charts reviewed, evidence of shunt-induced neurologic deficits was seen in 63 patients. Thirty-four patients had back pain with or without sciatica, 45 patients had hamstring tightness, and 40 patients had foot deformities. Forty-nine patients had lumbar hyperlordosis, lordoscoliosis, and scoliosis. These deformities are postulated to be the result of arachnoiditis involving the conus medullaris and lower lumbar roots. PMID:3192696

  3. Piezoelectric RL shunt damping of flexible structures

    Høgsberg, Jan Becker; Krenk, Steen

    2015-01-01

    Resonant RL shunt circuits represent a robust and effective approach to piezoelectric damping, provided that the individual shunt circuit components are calibrated accurately with respect to the dynamic properties of the corresponding flexible structure. The balanced calibration procedure applied...

  4. Staged Transcatheter Treatment of Portal Hypoplasia and Congenital Portosystemic Shunts in Children

    Purpose: Congenital portosystemic shunts (CPSS) with portal venous hypoplasia cause hyperammonemia. Acute shunt closure results in portal hypertension. A transcatheter method of staged shunt reduction to afford growth of portal vessels followed by shunt closure is reported. Methods: Pressure measurements and angiography in the CPSS or superior mesenteric artery (SMA) during temporary occlusion of the shunt were performed. If vessels were diminutive and the pressure was above 18 mmHg, a staged approach was performed, which included implantation of a tailored reducing stent to reduce shunt diameter by ∼50 %. Recatheterization was performed approximately 3 months later. If the portal pressure was below 18 mmHg and vessels had developed, the shunt was closed with a device. Results: Six patients (5 boys, 1 girl) with a median age of 3.3 (range 0.5–13) years had CPSS portal venous hypoplasia and hyperammonemia. Five patients underwent staged closure. One patient tolerated acute closure. One patient required surgical shunt banding because a reducing stent could not be positioned. At median follow-up of 3.8 (range 2.2–8.4) years, a total of 21 procedures (20 transcatheter, 1 surgical) were performed. In all patients, the shunt was closed with a significant reduction in portal pressure (27.7 ± 11.3 to 10.8 ± 1.8 mmHg; p = 0.016), significant growth of the portal vessels (0.8 ± 0.5 to 4.0 ± 2.4 mm; p = 0.037), and normalization of ammonia levels (202.1 ± 53.6 to 65.7 ± 9.6 μmol/L; p = 0.002) with no complications. Conclusion: Staged CPSS closure is effective in causing portal vessel growth and treating hyperammonemia

  5. Percutaneous Transjugular Direct Porto-caval Shunt in Patients with Budd-Chiari Syndrome

    The purpose of the study was to evaluate the feasibility and effectiveness of direct porto-caval shunts in patients with Budd-Chiari syndrome (BCS) in whom there is no access to the hepatic veins during transjugular intrahepatic portosystemic shunt (TIPSS). We included six consecutive patients with fulminant/acute Budd-Chiari syndrome (mean age: 35 years) in whom a conventional TIPSS was not possible due to inaccessible hepatic veins. We performed a direct porto-caval shunt via a transhepatic approach. Patients were followed up by means of clinical examination, laboratory investigations, and Doppler ultrasound. TIPSS implantation from the inferior vena cava (IVC) was successful in all six patients (100%). The median transhepatic shunt length was 9 cm (8-10 cm). No procedure-related complications were observed in our patients. Early shunt occlusion occurred in three out of six patients (50%). In all three of these patients, the stent used to stabilize the shunt ended 1-2 cm before reaching the IVC. All occlusions were successfully recanalized. One of these patients developed recurrent early shunt as well as mesenteric and splenic vein occlusions. She died 7 days after TIPSS placement due to an unmanageable coagulation disorder. The remaining five patients were followed up by planned clinical examination and laboratory investigations (mean follow-up time was 15 months; patient 1 was followed up for 13 months, patient 2 for 14 months, patient 3 for 15 months, and patients 4 and 5 for 16 months) and all displayed a complete and durable resolution of liver failure and ascites without reintervention. In patients with acute liver failure originating from BCS and inaccessible hepatic veins, a direct transhepatic porto-caval shunt can be performed safely and effectively under ultrasound guidance. Future studies in larger patient groups should investigate if the patency of transcaval TIPSS with long transhepatic shunt segments is similar compared to conventional TIPSS via

  6. Staged Transcatheter Treatment of Portal Hypoplasia and Congenital Portosystemic Shunts in Children

    Bruckheimer, Elchanan, E-mail: elchananb@bezeqint.net; Dagan, Tamir [Schneider Children' s Medical Center Israel, Section of Pediatric Cardiology (Israel); Atar, Eli; Schwartz, Michael [Schneider Children' s Medical Center Israel, Section of Radiology (Israel); Kachko, Ludmila [Schneider Children' s Medical Center Israel, Section of Anesthesiology (Israel); Superina, Riccardo; Amir, Gabriel [Schneider Children' s Medical Center Israel, Section of Pediatric Cardiology (Israel); Shapiro, Rivka [Schneider Children' s Medical Center Israel, Section of Gastroenterology (Israel); Birk, Einat [Schneider Children' s Medical Center Israel, Section of Pediatric Cardiology (Israel)

    2013-12-15

    Purpose: Congenital portosystemic shunts (CPSS) with portal venous hypoplasia cause hyperammonemia. Acute shunt closure results in portal hypertension. A transcatheter method of staged shunt reduction to afford growth of portal vessels followed by shunt closure is reported. Methods: Pressure measurements and angiography in the CPSS or superior mesenteric artery (SMA) during temporary occlusion of the shunt were performed. If vessels were diminutive and the pressure was above 18 mmHg, a staged approach was performed, which included implantation of a tailored reducing stent to reduce shunt diameter by {approx}50 %. Recatheterization was performed approximately 3 months later. If the portal pressure was below 18 mmHg and vessels had developed, the shunt was closed with a device. Results: Six patients (5 boys, 1 girl) with a median age of 3.3 (range 0.5-13) years had CPSS portal venous hypoplasia and hyperammonemia. Five patients underwent staged closure. One patient tolerated acute closure. One patient required surgical shunt banding because a reducing stent could not be positioned. At median follow-up of 3.8 (range 2.2-8.4) years, a total of 21 procedures (20 transcatheter, 1 surgical) were performed. In all patients, the shunt was closed with a significant reduction in portal pressure (27.7 {+-} 11.3 to 10.8 {+-} 1.8 mmHg; p = 0.016), significant growth of the portal vessels (0.8 {+-} 0.5 to 4.0 {+-} 2.4 mm; p = 0.037), and normalization of ammonia levels (202.1 {+-} 53.6 to 65.7 {+-} 9.6 {mu}mol/L; p = 0.002) with no complications. Conclusion: Staged CPSS closure is effective in causing portal vessel growth and treating hyperammonemia.

  7. Severe respiratory failure following ventriculopleural shunt

    Shahzad Alam; Manjunath, Nagaraju M.

    2015-01-01

    Cerebrospinal fluid (CSF) diversion procedure has been used for long to treat hydrocephalus in children. The principle of shunting is to establish a communication between the CSF and a drainage cavity (peritoneum, right atrium, and pleura). Ventriculoperitoneal shunt is used most commonly, followed secondly by ventriculopleural shunt (VPLS). Hydrothorax due to excessive CSF accumulation is a rare complication following both the type of shunts and is more frequently seen with VPLS. We report a...

  8. Scintigraphic demonstration of the permeability of peritoneo-caval shunts (Denver's shunts)

    The functional ability of a peritoneo-caval shunt ('Denver's' Shunt) can be examined in a physiological manner by means of nuclear medical procedures. For this purpose macroaggregated albumin particles used for lung scintigraphy are injected intraperitoneally. The visualization of these particles within the lung capillaries, combined with the possibility of recording a lung perfusion scintigram, gives evidence of the regular function of the shunt. In many cases, scintigraphy also reveals the course of the shunt itself. This enables the shunt to be saved because shunt puncture is not necessary. Such puncture would be required only for X-ray localisation using contrast media in cases of proven shunt occlusion. (orig.)

  9. Automatic detection and analysis of nuclear plant malfunctions

    In this paper a system is proposed, which performs dynamically the detection and analysis of malfunctions in a nuclear plant. The proposed method was developed and implemented on a Reactor Simulator, instead of on a real one, thus allowing a wide range of tests. For all variables under control, a simulation module was identified and implemented on the reactor on-line computer. In the malfunction identification phase all modules run separately, processing plant input variables and producing their output variable in Real-Time; continuous comparison of the computed variables with plant variables allows malfunction's detection. At this moment the second phase can occur: when a malfunction is detected, all modules are connected, except the module simulating the wrong variable, and a fast simulation is carried on, to analyse the consequences. (author)

  10. Fibrous capsule formation of the peritoneal catheter tip in ventriculoperitoneal shunt: Two case reports

    Tomoaki Kano

    2014-01-01

    Full Text Available Background: A fibrous capsule formation of a peritoneal catheter tip has not previously been researched as a complication of ventriculoperitoneal (VP shunts. Case Description: Two adult patients who had undergone a VP shunt for communicative hydrocephalus following subarachnoid hemorrhage caused by a ruptured aneurysm have been identified with malfunction of the VP shunt system by mild disturbance of consciousness and gait disturbance or loss of appetite. Hydrocephalus was diagnosed by computed tomography and the obstruction of the peritoneal catheter was revealed by shuntgraphy. Laparoscopy was performed and the peritoneal catheter tips were obstructed by fibrous white capsules that covered them. One was a thin membranous capsule like a stocking with two small endoluminal granulomas of the peritoneal catheter, and other one was a fibrous glossy white capsule like a sock. These fibrous capsules were excised by laparoscopy forceps without the conversion to a new peritoneal catheter. Following the procedure, the shunt functioned normally. The pathological diagnoses were peritoneum with foreign body reaction or hyalinization of membranous tissue surrounded by fibrous tissue. Conclusion: These fibrous capsules might be formed by the peritoneal reaction to cerebrospinal fluid as a foreign material. As such, a periodic medical check should be scheduled since a fibrous capsule of the peritoneal catheter tip might be formed again.

  11. Transjugular Intrahepatic Portosystemic Shunt (TIPS)

    Full Text Available ... overnight at the hospital for one or more days. What is Transjugular Intrahepatic Portosystemic Shunt (TIPS)? What are some common uses of the procedure? How should I prepare? What does the equipment look like? How does the procedure work? How is the procedure performed? What will I ...

  12. Transjugular Intrahepatic Portosystemic Shunt (TIPS)

    Full Text Available ... Español More Info Images/Videos News Physician Resources Professions Site Index A-Z Transjugular Intrahepatic Portosystemic Shunt ( ... blood pressure and pulse during the procedure. A nurse or technologist will insert an intravenous (IV) line ...

  13. Transjugular Intrahepatic Portosystemic Shunt (TIPS)

    Full Text Available ... What are the limitations of TIPS? What is a Transjugular Intrahepatic Portosystemic Shunt (TIPS)? A transjugular intrahepatic ... encourage linking to this site. × Recommend RadiologyInfo to a friend Send to (friend's e-mail address): From ( ...

  14. Percutaneous transhepatic portacaval shunt (PTPS)

    Objective: To present a latest procedures for portal hypertension with preliminary results and evaluate the technical feasibility and efficacy of the portacaval shunt creation through percutaneous transhepatic approach with its potential clinical significance. Methods: Nineteen patients with portal hypertension (17 men; mean age 57 years, range 32-73) were referred for PTPS procedure because of bleeding varices (n=16), intractable ascites (n=2), and hepatopulmonary syndrome (n=1). The severity of liver disease was Child's B in 4 and Child's C in 15. The PTPS was created by a percutaneous transhepatic puncture through left portal vein to the IVC and a polytetrafluoroethylene (PTFE) stent-grafts was placed through a transhepatic approach. Results: Technical and functional successes were achieved in all patients-arerage without any procedure-related complications. The postprocedural portal vein-IVC gradients decreased with a mean 13 cmH2O and with average 216 days of follow-up showing no recurrent variceal bleeding and refractory ascites. The primary patency ratefor 365 days was 94.8%, obviously higher than classical TIPS. Conclusions: Portacaval shunt creation using the percutaneous transhepatic technique is secure and feasible with favorable primary patency due to the a straight line shunt construction and provide a good alternative to the standard portosystemic shunt in difficult or impossible circumstances. (authors)

  15. 30 CFR 75.352 - Actions in response to AMS malfunction, alert, or alarm signals.

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Actions in response to AMS malfunction, alert... § 75.352 Actions in response to AMS malfunction, alert, or alarm signals. (a) When a malfunction, alert... of a malfunction, alert, or alarm signal, appropriate personnel must promptly initiate...

  16. Ectopic cystoperitoneal shunt demonstrated by valvulography. A case report

    The most important and frequent complications in the management of hydrocephalus treated with a derivation system are the infection and obstruction of the ventriculoperitoneal or ventriculoatrial shunt. However, another less frequent problem is the migration of the distal catheter. The case report presented is a 20 year-old girl who started, when she was 12, with severe headaches and epileptogenic seizures. She was diagnosed with a left parietotemporal aracnoidal cyst and a cystoperitoneal shunt was installed. However, she continued to have headaches. In September 1999, the derivation system was controlled with a radionuclide valvulography, which demonstrated shunt patency, with mild ectasis in the distal region. In July 2000, another valvulography showed a malfunction of the cystoperitoneal system. The distal catheter was surgically reviewed and repositioned. A few months of being asymptomatic, the headaches returned with a cough, which didn't respond to treatment. In February of 2002, she was referred to the Military Hospital Nuclear Medicine Department and a radionuclide valvulography was performed with 370 MBq of Tc99m-DTPA, injected in the derivative system reservoir. Images showed a slow descension of the radionuclide until the xifoides region where the distal catheter had formed a loop into the chest. Free activity was observed at the end of the catheter with another abnormal traject in the middle chest up to the top of the sternum. A pumping test was done and the patient coughed and said that she 'felt water' in her mouth. A simple abdomen X-ray was performed confirming the distal catheter in the upper side of the diaphragm. A third surgery was performed demonstrating that the catheter had an intraperitoneal loop with the distal end in the chest. They pulled the catheter and the distal end was repositioned into the peritoneal cavity, controlling its functioning. A simple abdomen X-ray verified the position. In the following days the patient had no headache

  17. Effect of peritoneo-venous shunt on portal pressure.

    Samanta, A K; Leevy, C M

    1989-01-01

    The cause of variceal bleed after a peritoneo-venous shunt is not known. Portal haemodynamic consequences of a peritoneo-venous shunt are poorly understood. The most critical period after a peritoneo-venous shunt is the early postoperative period when rapid mobilisation of peritoneal fluid occurs. Serial changes in the portal pressure during the early postoperative period have not been recorded. In the present study preoperative wedge hepatic vein (WHV), right atrial (RA) and pulmonary capillary wedged (PCW) pressures, cardiac index (CI), and plasma volume (PV) were measured in five alcoholic cirrhotic patients with tense ascites for up to 20 hours postoperatively. The longterm effect was assessed by repeating the intrahepatic and/or wedged hepatic vein pressures in three of the surviving patients after 10 to 20 months. A significant increase in the circulatory dynamics and portal pressure was seen within two hours after shunt placement. Wedged hepatic vein pressure increased from 27.6 (8.2) mmHg to 37.2 (9.2) mmHg (p less than 0.01), RA pressure increased from 6.8 (1.5) mmHg to 14.0 (4.3) mmHg (p less than 0.05), PCW increased from 7.2 (3.5) mmHg to 19.3 (5.7) mmHg (p less than 0.01), CI increased from 3.4 (0.27) lit/m2/min to 4.3 (0.85) lit/m2/min (p less than 0.05). This was accompanied by a 34% increase in the plasma volume from 1838.5 (142.1) to 2471.4 (210) ml/m2. These derangements were maintained up to 20 hours postoperatively. After 10 to 20 months, repeat measurements revealed a return to preoperative measurements. It is concluded that there is an acute increase portal pressure after a peritoneo-venous shunt attributed to increased circulation plasma volume, resulting from rapid mobilisation of ascitic fluid after the shunt. A sudden increase in portal pressure might be an important provoking factor for variceal bleeding after peritoneo-venus shunt. PMID:2920931

  18. Detection of thermocouple malfunction in the Beacon system

    The BEACON system uses Core Exit Thermocouples (T/C) extensively for continuous radial power distribution monitoring. The T/C's are used to adjust the reference power distribution generated by the BEACON system to match the current radial power distribution. T/C reliability, repeatability, and relative accuracy have been very satisfactory. However, it is very important to detect any T/C malfunctions during operation, since a T/C signal change caused by an undetected malfunction can lead to serious errors in the radial power distribution developed by BEACON. A simple procedure has been developed which is capable of discriminating between changes in T/C signals caused by actual changes in reactor conditions and signal changes caused by T/C malfunctions

  19. Cross-sectional imaging of thoracic and abdominal complications of cerebrospinal fluid shunt catheters.

    Bolster, Ferdia; Fardanesh, Reza; Morgan, Tara; Katz, Douglas S; Daly, Barry

    2016-04-01

    This study aims to review the imaging findings of distal (thoracic and abdominal) complications related to ventriculo-peritoneal (VP), ventriculo-pleural (VPL), and ventriculo-atrial (VA) cerebrospinal fluid (CSF) shunt catheter placement. Institution review board-approved single-center study of patients with thoracic and abdominal CSF catheter-related complications on cross-sectional imaging examinations over a 14-year period was performed. Clinical presentation, patient demographics, prior medical history, and subsequent surgical treatment were recorded. The presence or absence of CSF catheter-related infection and/or acute hydrocephalus on cross-sectional imaging was also recorded. There were 81 distal CSF catheter-related complications identified on 47 thoracic or abdominal imaging examinations in 30 patients (age 5-80 years, mean 39.3 years), most often on CT (CT = 42, MRI = 1, US = 4). Complications included 38 intraperitoneal and 11 extraperitoneal fluid collections. Extraperitoneal collections included nine abdominal wall subcutaneous (SC) pseudocysts associated with shunt migration and obesity, an intrapleural pseudocyst, and a breast pseudocyst. There were also two large VPL-related pleural effusions, a fractured catheter in the SC tissues, and a large VA shunt thrombus within the right atrium. Ten patients (33.3 %) had culture-positive infection from CSF or shunt catheter samples. Ten patients (33.3 %) had features of temporally related acute or worsening hydrocephalus on neuroimaging. In four of these patients, the detection of thoracic and abdominal complications on CT preceded and predicted the findings of acute hydrocephalus on cranial imaging. Thoracic and abdominal complications of CSF shunts, as can be identified on CT,  include shunt infection and/or obstruction, may be both multiple and recurrent, and may be predictive of concurrent acute intracranial problems. PMID:26610766

  20. Intra-abdominal metastasis of an intracranial germinoma via ventriculo-peritoneal shunt in a 13-year-old female.

    Murray, Matthew J; Metayer, Lucy E; Mallucci, Conor L; Hale, Juliet P; Nicholson, James C; Kirollos, Ramez W; Burke, G A Amos

    2011-12-01

    A 13-year-old patient presented with massive intra-abdominal metastasis and spontaneous acute tumour lysis syndrome, 17-months after VP shunt placement for metastatic pineal germinoma treated with cranio-spinal-irradiation. Hyperhydration/rasburicase improved renal function, allowing chemotherapy with subsequent surgery. The patient remains event-free 34-months later. Risk of intra-abdominal metastasis from VP shunts is discussed. PMID:21501064

  1. Right Lower Quadrant Abdominal Pain in a Patient with Prior Ventriculoperitoneal Shunting: Consider the Tip!

    Petros Charalampoudis

    2012-01-01

    Full Text Available Introduction. Ventriculoperitoneal (VP shunting is the treatment of choice for nonobstructive hydrocephalus. In patients with such a device, right lower quadrant abdominal pain can puzzle the surgeon, posing a differential diagnostic problem among appendicitis, nonsurgical colicky pain, and primary shunt catheter tip infection. Treatment is different in either case. Presentation of Case. We hereby present a case of a young woman with prior ventriculoperitoneal shunt positioning who presented to our department with right lower quadrant abdominal pain. The patient underwent a 24-hour observation including a neurosurgery consult in order to exclude acute appendicitis and VP shunt tip infection. Twenty four hours later, the patient’s symptomatology improved, and she was discharged with the diagnosis of atypical colicky abdominal pain seeking a gastroenterologist consult. Discussion. This case supports that when a patient with prior VP shunting presents with right lower quadrant abdominal pain, differential diagnosis can be tricky for the surgeon. Conclusion. Apart from acute appendicitis, primary or secondary VP catheter tip infection must be considered because the latter can be disastrous.

  2. Scintigraphic demonstration of the permeability of peritoneo-caval shunts (Denver's shunts)

    Grehn, S.; Pingel, B.

    1988-02-01

    The functional ability of a peritoneo-caval shunt ('Denver's' Shunt) can be examined in a physiological manner by means of nuclear medical procedures. For this purpose macroaggregated albumin particles used for lung scintigraphy are injected intraperitoneally. The visualization of these particles within the lung capillaries, combined with the possibility of recording a lung perfusion scintigram, gives evidence of the regular function of the shunt. In many cases, scintigraphy also reveals the course of the shunt itself. This enables the shunt to be saved because shunt puncture is not necessary. Such puncture would be required only for X-ray localisation using contrast media in cases of proven shunt occlusion.

  3. Method of diagnosis of functional intrapulmonary shunts

    A method of diagnosing functional intrapulmonary shunts is suggested, that permits to obtain the data on the amount, localization and sizes of shunts. This method can be used in the clinic of internal deseases to determine the state of cardiopulmonary patients

  4. 49 CFR 236.56 - Shunting sensitivity.

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Shunting sensitivity. 236.56 Section 236.56 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION...: All Systems Track Circuits § 236.56 Shunting sensitivity. Each track circuit controlling home...

  5. 49 CFR 234.229 - Shunting sensitivity.

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Shunting sensitivity. 234.229 Section 234.229 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION..., Inspection, and Testing Maintenance Standards § 234.229 Shunting sensitivity. Each highway-rail...

  6. Performance of piezoelectric shunts for vibration reduction

    This work addresses passive reduction of structural vibration by means of shunted piezoelectric patches. The two classical resistive and resonant shunt solutions are considered. The main goal of this paper is to give closed-form solutions to systematically estimate the damping performances of the shunts, in the two cases of free and forced vibrations, whatever the elastic host structure is. Then it is carefully demonstrated that the performance of the shunt, in terms of vibration reduction, depends on only one free parameter: the so-called modal electromechanical coupling factor (MEMCF) of the mechanical vibration mode to which the shunts are tuned. Experiments are proposed and an excellent agreement with the model is obtained, thus validating it. (paper)

  7. Radioisotopic evaluation of peritoneo-venous shunt patency by intraperitoneal injection of 99m-Tc-human albumin microspheres

    The results demonstrate that 99m Tc-human albumin microspheres always reach the lungs when the shunt is patent. On the contrary, in presence of malfunctioning, they are either confined below the diaphragm or stopped at some point along the tube according to the site of interruption, either in the valve or in venous limb of the shunt. A second injection of the tracer directly into the subcutaneous portion of the tube, immediately above the valve, proved to be very useful to confirm the valvular site of obstruction. The early visualization of the tube seems to indicate a normal flow through the valve even when the last segment of the shunt is obstructed. A poor image of the tube and a delayed accumulation of the tracer in the lungs could indicate the presence of a nonfunctioning valve; in this case, however, an associated heart disease must be ruled out. The present radioisotopic technique prompts early surgical revision when the shunt is not patent. Although the site of interruption can not be exactly determined, the method discriminates between valve and tube shut-off, thus avoiding the replacement of the whole apparatus. This radioisotopic method should be used routinely for the control of PVS patency in cirrhotic patients. Though slightly invasive, it is simple and time-saving. Finally, 99m Tc-human albumin microspheres are useful radioactive tracers because of their easy passage into the LeVeen tube and their homogeneous diffusion in the lungs

  8. [Systemic-pulmonary artery shunt using Golaski graft: trial for measurement of the shunt flow].

    Togo, T; Ito, T; Hata, M; Murata, S; Osaka, K; Komatsu, T; Tabayashi, K; Haneda, K; Mohri, T

    1995-03-01

    For the systemic-pulmonary artery shunt operation, the modified Blalock-Taussig shunt was the first choice for procedure in our institution. Since 1990, Golaski knitted Dacron graft (4 or 5 mm in diameter) was used for the prosthesis. Ex-vivo flow calibration of the electromagnetic flow meter (Nihon Koden, MFV-3100) to Golaski graft showed good correlation between the real flow and value measured by the electromagnetic flow meter. Shunt flow was measured in the consecutive clinical fifteen cases. The shunt flow per body surface area of the patient who required additional shunt operation was 721 ml/min/m2 and one patient in whom the congestive heart failure developed after the shunt operation, had the shunt flow of 3,022 ml/min/m2. The adequate shunt flow in these cases was ranged from 745 to 2,820 ml/min/m2 (mean +/- 1 SD, 1,490 +/- 587.8). Therefore we performed the systemic-pulmonary artery shunt operation using Golaski graft to get the shunt flow of 1,000 ml/min/m2 (approximately a third of cardiac index) for the guide of good results. PMID:7897896

  9. Preoperative shunts in thalamic tumours.

    Goel A

    2000-10-01

    Full Text Available Thirty one patients with thalamic glioma underwent a pre-tumour resection shunt surgery. The procedure was uneventful in 23 patients with relief from symptoms of increased intracranial pressure. Eight patients worsened after the procedure. The level of sensorium worsened from excessively drowsy state to unconsciousness in seven patients. Three patients developed hemiparesis, 4 developed paresis of extra-ocular muscles and altered pupillary reflexes, and 1 developed incontinence of urine and persistent vomiting. Alteration in the delicately balanced intracranial pressure and movements in the tumour and vital adjacent brain areas could be the probable cause of the worsening in the neurological state in these 8 patients. On the basis of these observations and on review of literature, it is postulated that the ventricular dilatation following an obstruction in the path of the cerebrospinal fluid flow by a tumour could be a natural defense phenomenon of the brain.

  10. Classification system for reporting events involving human malfunctions

    The report describes a set of categories for reporting industrial incidents and events involving human malfunction. The classification system aims at ensuring information adequate for improvement of human work situations and man-machine interface systems and for attempts to quantify ''human error'' rates. The classification system has a multifacetted non-hierarchial structure and its compatibility with Ispra's ERDS classification is described. The collection of the information in general and for quantification purposes are discussed. 24 categories, 12 of which being human factors oriented, are listed with their respective subcategories, and comments are given. Underlying models of human data processes and their typical malfunctions and of a human decision sequence are described. (author)

  11. Echocardiographic analysis of a malfunctioning Davila-Sierra mitral valve

    Tri, Terry B.; Gregoratos, Gabriel

    1981-01-01

    Although the Davila-Sierra mitral valve prosthesis was removed from the market nearly a decade ago, a number of patients still have this valve in place. We recently studied the echocardiographic features of a malfunctioning Davila-Sierra mitral valve prosthesis. Abnormalities that suggested improper functioning of the prosthesis included a markedly delayed poppet opening and an early diastolic hump believed to represent motion of the mitral annulus. Previously described echocardiographic indi...

  12. Evaluation of Intrapulmonary Shunt Alterations at Different Oxygen Concentrations and Oxygenation Parameters

    Zerrin Demirtürk

    2015-06-01

    Full Text Available Aim: The aim of the current study was to evaluate the relationship of intrapulmonary shunt with FiO2 alterations in patients treated with mechanical ventilation in intensive care unit for extrapulmonary disorders. Also, we aimed to assess the role of correlation between shunt ratio and PaO2/FiO2, PaO2/PAO2, P(A-a O2 values in determining the treatment strategies. Methods: Twenty patients between ages of 19 and 75 years, requiring mechanical ventilation were enrolled into the study. We excluded two patients due to congestive heart failure and two patients due to acute respiratory distress syndrome (ARDS. Shunt fraction, P(A-aO2, PaO2/FiO2, PaO2/PAO2 values were calculated at each FiO2 level for each patient. Results: The lowest median shunt value was measured at FiO2: 0.3 There was a significant correlation between shunt values at FiO2 0.5 and 0.7 (r=0.850. The highest mean value of P(A-aO2 was measured at FiO2: 1 (382.91±106.46, and the lowest value of P(A-aO2 was measured at FiO2: 0.21 (38.64±16.97. PaO2/FiO2 and PaO2/PAO2 ratios measured at FiO2: 0.3 and 0.5 were found to be statistically significant. Conclusion: In this study, we have shown increased shunt fraction at FiO2: 1 level. Different oxygenation indices and shunt measurements give us important and useful knowledge about the patients’ current condition. (The Medical Bulletin of Haseki 2015; 53:124-9

  13. Over-drainage and persistent shunt-dependency in patients with idiopathic intracranial hypertension treated with shunts and bariatric surgery

    Jonathan Roth

    2015-01-01

    Conclusions: Patients with IIH that undergo shunt surgery and BS (not concomitantly may suffer from OD symptoms, necessitating multiple shunt revisions, and valve upgrades. Despite BS being a valid primary treatment for some patients with IIH, among shunted patients, BS may not lead to resolution of IIH-related symptoms and patients may remain shunt-dependent.

  14. Arne Torkildsen and the ventriculocisternal shunt: the first clinically successful shunt for hydrocephalus.

    Eide, Per Kristian; Lundar, Tryggve

    2016-05-01

    Arne Torkildsen was a pioneering Norwegian neurosurgeon who introduced the ventriculocisternal shunt, the first clinically successful shunt for CSF diversion in hydrocephalus. The procedure, usually referred to as ventriculocisternostomy (VCS), Torkildsen's operation, orTorkildsen's shunt, became internationally recognized as an efficient operation for the treatment of noncommunicating hydrocephalus. The operation gained widespread use in the 1940s and 1950s before the introduction of extracranial shunts. In this paper, the authors look more closely at Torkildsen's development of the VCS and examine how this surgical approach differed from other procedures for treating hydrocephalus before World War II. Long-term results of the VCS are presented. PMID:26339852

  15. Idiopathic intracranial hypertension: lumboperitoneal shunts versus ventriculoperitoneal shunts--case series and literature review.

    Abubaker, Khalid

    2012-02-01

    OBJECTIVES: Idiopathic intracranial hypertension (IIH) is an uncommon but important cause of headache that can lead to visual loss. This study was undertaken to review our experience in the treatment of IIH by neuronavigation-assisted ventriculoperitoneal (VP) shunts with programmable valves as compared to lumboperitoneal (LP) shunts. METHODS: A retrospective chart review was conducted on 25 patients treated for IIH between 2001 and 2009. Age, sex, clinical presentation, methods of treatment and failure rates were recorded. RESULTS: Seventy-two per cent were treated initially with LP shunts. Failure rate was 11% in this group. Neuronavigation-assisted VP shunts were used to treat 28%. In this group, the failure rate was 14%. CONCLUSION: Our experience indicates that both LP shunts and VP shuts are effective in controlling all the clinical manifestations of IIH in the immediate postoperative period. Failure rates are slightly higher for VP shunts (14%) than LP shunts (11%). However, revision rates are higher with LP shunts (60%) than with VP shunts (30%).

  16. Syringosubarachnoid shunting using a myringotomy tube

    Leschke, Jack M.; Mumert, Michael L.; Kurpad, Shekar N.

    2016-01-01

    Background: Syringomyelia results from obstruction of cerebrospinal fluid (CSF) flow due to a multitude of causes. Often symptoms of pain, weakness, and sensory disturbance are progressive and require surgical treatment. We present here a rare technique for syringosubarachnoid shunting. Case Description: We present the case of a 38-year-old male who suffered a traumatic cervical spinal cord injury due to a motor vehicle accident. With progressive pain and motor decline, a magnetic resonance imaging was obtained and showed a new syrinx extending cervical multiple segments. A unique surgical procedure using a myringotomy tube to shunt CSF into the subarachnoid space was employed in this case. The patient's examination stabilized postoperatively, and at 2 months and 6 months follow-up visits, his strength and sensation continued to improve. Conclusion: We used a myringotomy tube for syringosubarachnoid shunting for the surgical management of a posttraumatic syrinx with good results. This technique minimizes suturing and may minimize shunt-related complications. PMID:26862456

  17. Severe respiratory failure following ventriculopleural shunt

    Shahzad Alam

    2015-01-01

    Full Text Available Cerebrospinal fluid (CSF diversion procedure has been used for long to treat hydrocephalus in children. The principle of shunting is to establish a communication between the CSF and a drainage cavity (peritoneum, right atrium, and pleura. Ventriculoperitoneal shunt is used most commonly, followed secondly by ventriculopleural shunt (VPLS. Hydrothorax due to excessive CSF accumulation is a rare complication following both the type of shunts and is more frequently seen with VPLS. We report a case of a 6-year-old female child presenting with massive CSF hydrothorax with respiratory failure following VPLS. The aim of the article is to highlight early recognition of this rare and life-threatening condition, which could easily be missed if proper history is not available.

  18. Mesoatrial shunt in Budd-Chiari syndrome

    Mirković Darko

    2009-01-01

    Full Text Available Background. Budd-Chiari syndrome (BCS represents partial or total occlusion of the hepatic veins with or without simultaneous obstruction of vena cava inferior (VCI. The symptoms of BCS are abdominal pain, hepatomegaly, ascites, varices of the abdominal wall, sometimes bleeding from the upper part of gastointestinal tract (GIT, lower limbs swelling and jaundice. Primary BSC is a relatively rare condition occurring in one per 100 000 of the population worldwide. Case report. A male patient, 25-year-old, facing tooth postextraction complications, was presented with acute BCS. On admission, physical examination revealed pale-grayish complexion, more pronounced veins over the thorax and abdomen, ascites, enlarged liver rising 8 cm below the right costal arch and having a minor pleural effusion by the right side. The patient was submitted to Doppler sonography and computed tomography (CT that verified the right leg deep veins thrombosis, as well as the presence of a thrombus in the intrahepatic portion of the VCI. Multislice computed tomography (MSCT showed occlusion of hepatic veins (Budd-Chiari syndrome and thrombosis of the VCI in the retrohepatic part 6 cm long. Also, increased values of transaminases and gamma GT and reduced values of albumines and serum ferrum were registered. Molecular examination revealed Factor V Leiden mutation - heterozygote. After preoperative preparations a mesocaval shunt was made using Gore- Tex ring graft of 12 mm. Intraoperatively, the blue enlarged liver was found with almost black zones of tense capsule. After a graft making, liver congestion decreased followed by the change of colour and volume. Within postoperative course metabolic and synthetic liver functions were obvious. Conclusion. In patients with BCS medicamentous treatment does not yield adequate results, but even causes worsening of general condition. Surgical therapy in the presented patient was performed timely regarding the stage of the disease due to

  19. Congenital portosystemic shunts with and without gastrointestinal bleeding - case series

    Gong, Ying; Chen, Jun; Chen, Qi; Ji, Min; Pa, Mier; Qiao, Zhongwei [Children' s Hospital of Fudan University, Department of Radiology, Shanghai (China); Zhu, Hui [Fudan University Shanghai Cancer Center, Department of Radiology, Shanghai (China); Zheng, Shan [Children' s Hospital of Fudan University, Department of Surgery, Shanghai (China)

    2015-12-15

    The clinical presentation of congenital portosystemic shunt is variable and gastrointestinal bleeding is an uncommon presentation. To describe the imaging features of congenital portosystemic shunt as it presented in 11 children with (n = 6) and without gastrointestinal bleeding (n = 5). We performed a retrospective study on a clinical and imaging dataset of 11 children diagnosed with congenital portosystemic shunt. A total of 11 children with congenital portosystemic shunt were included in this study, 7 with extrahepatic portosystemic shunts and 4 with intrahepatic portosystemic shunts. Six patients with gastrointestinal bleeding had an extrahepatic portosystemic shunt, and the imaging results showed that the shunts originated from the splenomesenteric junction (n = 5) or splenic vein (n = 1) and connected to the internal iliac vein. Among the five cases of congenital portosystemic shunt without gastrointestinal bleeding, one case was an extrahepatic portosystemic shunt and the other four were intrahepatic portosystemic shunts. Most congenital portosystemic shunt patients with gastrointestinal bleeding had a shunt that drained portal blood into the iliac vein via an inferior mesenteric vein. This type of shunt was uncommon, but the concomitant rate of gastrointestinal bleeding with this type of shunt was high. (orig.)

  20. Temporary intravascular shunts for peripheral vascular trauma.

    Husain A

    1992-04-01

    Full Text Available Polyvinylchloride (PVC disposable endotracheal suction catheters were successfully used as temporary intravascular shunts in 5 patients of popliteal artery trauma. These simple shunts should be used routinely in such conditions to immediately re-establish blood supply to the ischaemic limb particularly in patients of polytrauma where systemic anticoagulation is contraindicated. This avoids the inherent delay prior to vascular repair and reduces the incidence of irreversible ischemia.

  1. Cell shunt resistance and photovoltaic module performance

    McMahon, T.J.; Basso, T.S.; Rummel, S.R. [National Renewable Energy Lab., Golden, CO (United States)

    1996-05-01

    Shunt resistance of cells in photovoltaic modules can affect module power output and could indicate flawed manufacturing processes and reliability problems. The authors describe a two-terminal diagnostic method to directly measure the shunt resistance of individual cells in a series-connected module non-intrusively, without deencapsulation. Peak power efficiency vs. light intensity was measured on a 12-cell, series-connected, single crystalline module having relatively high cell shunt resistances. The module was remeasured with 0.5-, 1-, and 2-ohm resistors attached across each cell to simulate shunt resistances of several emerging technologies. Peak power efficiencies decreased dramatically at lower light levels. Using the PSpice circuit simulator, the authors verified that cell shunt and series resistances can indeed be responsible for the observed peak power efficiency vs. intensity behavior. The authors discuss the effect of basic cell diode parameters, i.e., shunt resistance, series resistance, and recombination losses, on PV module performance as a function of light intensity.

  2. Idiopathic intracranial hypertension: lumboperitoneal shunts versus ventriculoperitoneal shunts--case series and literature review.

    Abubaker, Khalid

    2011-02-01

    Idiopathic intracranial hypertension (IIH) is an uncommon but important cause of headache that can lead to visual loss. This study was undertaken to review our experience in the treatment of IIH by neuronavigation-assisted ventriculoperitoneal (VP) shunts with programmable valves as compared to lumboperitoneal (LP) shunts.

  3. Malfunction analysis of OPGW of stainless steel-unit structure

    李星梅; 张素芳; 王旭锋; 乞建勋

    2008-01-01

    Composite fiber optic overhead ground wire (OPGW) is increasingly applied in China’s overhead transmission lines. The stainless steel structure is adopted by most OPGWs as it is very small and easy to match the existing ground wire. The malfunction of OPGW in Beijing-Shanghai Optical Communication Project was analyzed through the chemical composition method and spectrum semi-quantitative method. The analysis indicates that the cable fault was due to the failure of seepage and irregular holes in the steel pipe of the optical unit. The rain water and the watery air entered into the optical units, and the water in turn became ice when temperature dropped. The occurrence of ice led to the acceleration of attenuation of the fiber. The results show that the rupture of stainless steel tube is mainly due to the instability of welding technique. The malfunction of OPGW is due to the local defects of welding seam because of local stress concentration in the manufacturing process.

  4. Simulation of Malfunctions for the ISS Double-Gimbal Control Moment Gyroscope

    Inampudi, Ravi; Gordeuk, John

    2016-01-01

    This paper presents a simplified approach to simulation of malfunctions of the Control Moment Gyroscope (CMG) on board the International Space Station (ISS). These malfunctions will be used as part of flight training of CMG failure scenarios in the guidance navigation control (GNC) subsystem of the Training Systems for 21st Century (TS21) simulator. The CMG malfunctions are grouped under mechanical, thermal and electrical categories. A malfunction can be as simple as one which only affects the telemetry or a complex one that changes the state and behavior of the CMG model. In both cases, the ISS GNC flight software will read the telemetry and respond accordingly. The user executes these malfunctions by supplying conditional data which modify internal model states and then elicit a response as seen on the user displays. Ground operators and crew on board the ISS use CMG malfunction procedures to better understand and respond to anomalies observed within the CMG subsystem.

  5. Neurogenic pulmonary edema due to ventriculo-atrial shunt dysfunction: a case report

    Ana Sofia Cruz; Sónia Menezes; Maria Silva

    2016-01-01

    ABSTRACT BACKGROUND AND OBJECTIVES: Pulmonary edema is caused by the accumulation of fluid within the air spaces and the interstitium of the lung. Neurogenic pulmonary edema is a clinical syndrome characterized by the acute onset of pulmonary edema following a significant central nervous system insult. It may be a less-recognized consequence of raised intracranial pressure due to obstructive hydrocephalus by blocked ventricular shunts. It usually appears within minutes to hours after the in...

  6. A canine model of multiple portosystemic shunting.

    Howe, L M; Boothe, H W; Miller, M W; Boothe, D M

    2000-01-01

    The objective of this study was to develop and describe an experimental canine model of multiple acquired portosystemic shunts (PSS) similar in nature to spontaneously occurring PSS. Sixteen dogs were used and were divided into a control (n = 6) and a diseased group (n = 10). Dogs of the diseased group were administered dimethylnitrosamine (2 mg/kg of body weight, po) twice weekly, and clinicopathologic, ultrasonographic, and hepatic scintigraphic findings were recorded during the development of hepatic disease and PSS. Surgery was then performed to permit visual verification of multiple shunts, catheter placement for portography examination, and biopsy of the liver. All diseased dogs developed severe hepatic disease and multiple PSS as documented visually at surgery and on portography. Based on this study, dimethylnitrosamine-induced portosystemic shunting appears to be an appropriate model for spontaneously occurring multiple PSS secondary to portal hypertension. PMID:10741951

  7. Coupling slots without shunt impedance drop

    It is well known that coupling slots between adjacent cells in a π-mode structure reduce shunt impedance per unit length with respect to single cell cavities. To design optimized coupling slots, one has to answer the following question: for a given coupling factor, what shape, dimension, position and number of slots lead to the lowest shunt impedance drop? A numerical study using the 3D code MAFIA has been carried out. The aim was to design the 352 MHz cavities for the high intensity proton accelerator of the TRISPAL project. The result is an unexpected set of four 'petal' slots. Such slots should lead to a quasi-negligible drop in shunt impedance: about -1% on average, for particle velocity from 0.4 c to 0.8 c. (author)

  8. Balanced calibration of resonant shunt circuits for piezoelectric vibration control

    Høgsberg, Jan; Krenk, Steen

    2012-01-01

    Shunting of piezoelectric transducers and suitable electric circuits constitutes an effective passive approach to resonant vibration damping of structures. Most common design concepts for resonant resistor-inductor (RL) shunt circuits rely on either maximization of the attainable modal damping...

  9. Two unusual complications of ventriculoperitoneal shunts in the same infant

    Ventriculoperitoneal shunts have been associated with many different complications. We describe two rare complications in a 10-month-old girl. To the best of our knowledge, protrusion of ventriculoperitoneal shunt through the knee has not been reported before. (orig.)

  10. Right-to-left shunt with hypoxemia in pulmonary hypertension

    2009-01-01

    Background: Hypoxemia is common in pulmonary hypertension (PH) and may be partly related to ventilation/perfusion mismatch, low diffusion capacity, low cardiac output, and/or right-to-left (RL) shunting. Methods: To determine whether true RL shunting causing hypoxemia is caused by intracardiac shunting, as classically considered, a retrospective single center study was conducted in consecutive patients with precapillary PH, with hypoxemia at rest (PaO(2) < 10 kPa), shunt fraction (Qs/Qt) grea...

  11. Internal carotid artery rupture caused by carotid shunt insertion

    Giulio Illuminati; Caliò, Francesco G.; Giulia Pizzardi; Francesco Vietri

    2015-01-01

    Introduction: Shunting is a well-accepted method of maintaining cerebral perfusion during carotid endarterectomy (CEA). Nonetheless, shunt insertion may lead to complications including arterial dissection, embolization, and thrombosis. We present a complication of shunt insertion consisting of arterial wall rupture, not reported previously. Presentation of case: A 78-year-old woman underwent CEA combined with coronary artery bypass grafting (CABG). At the time of shunt insertion an arteria...

  12. Subacute bacterial endocarditis and subsequent shunt nephritis from ventriculoatrial shunting 14 years after shunt implantation

    Burström, Gustav; Andresen, Morten; Bartek, Jiri;

    2014-01-01

    inconclusive multidisciplinary investigations, the patient progressed into end-stage renal disease before an echocardiogram revealed a vegetative plaque on the tendinous chords of the tricuspid valve. CSF cultures were grown from the shunt valve, confirming bacterial growth of Propionibacterium acnes suspected...

  13. 49 CFR 236.104 - Shunt fouling circuit.

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Shunt fouling circuit. 236.104 Section 236.104 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION...: All Systems Inspections and Tests; All Systems § 236.104 Shunt fouling circuit. Shunt fouling...

  14. Recurrent Breast Cancer in a Patient with a Ventriculoperitoneal Shunt

    Libby R. Copeland-Halperin

    2015-01-01

    Full Text Available We report a case of a patient with recurrent infiltrating ductal carcinoma of the breast encasing a ventriculoperitoneal shunt. We also review the current literature regarding reports of breast malignancy around a ventriculoperitoneal shunt, as well as the potential relevance of such shunts to the preoperative evaluation and management of patients with breast cancer.

  15. 21 CFR 876.5955 - Peritoneo-venous shunt.

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Peritoneo-venous shunt. 876.5955 Section 876.5955...) MEDICAL DEVICES GASTROENTEROLOGY-UROLOGY DEVICES Therapeutic Devices § 876.5955 Peritoneo-venous shunt. (a) Identification. A peritoneo-venous shunt is an implanted device that consists of a catheter and a...

  16. 21 CFR 882.4545 - Shunt system implantation instrument.

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Shunt system implantation instrument. 882.4545... implantation instrument. (a) Identification. A shunt system implantation instrument is an instrument used in the implantation of cerebrospinal fluid shunts, and includes tunneling instruments for passing...

  17. Round worm migration along ventriculoperitoneal shunt tract: a rare complication.

    Agarwal P

    2000-01-01

    Full Text Available Though a ventriculoperitoneal shunt has been associated with myriads of unusual complications, so has been that with roundworms. A case of a three-year-old boy is presented who had an unusual complication of roundworm migration along the shunt tract that presented as shunt tract infection.

  18. Classification system for reporting events involving human malfunctions

    The report describes a set of categories for reporting industrial incidents and events involving human malfunction. The classification system aims at ensuring information adequate for improvement of human work situations and man-machine interface systems and for attempts to quantify ''human error'' rates. The classification system has a multifacetted non-hierarchical structure and its compatibility with Ispra's ERDS classification is described. The collection of the information in general and for quantification purposes are discussed. 24 categories, 12 of which being human factors-oriented, are listed with their respective subcategories, and comments are given. Underlying models of human data process and their typical malfuntions and of a human decision sequence are described. The work reported is a joint contribution to the CSNI Group of Experts on Human Error Data and Assessment

  19. Platypnea-Orthodeoxia Syndrome: To Shunt or Not to Shunt, That is the Question

    Klein, Michael R.; Kiefer, Todd L.; Velazquez, Eric J.

    2016-01-01

    Platypnea-orthodeoxia syndrome is a rare disease defined by dyspnea and deoxygenation, induced by an upright position, and relieved by recumbency. Causes include shunting through a patent foramen ovale and pulmonary arteriovenous malformations.

  20. Muzzle shunt augmentation of conventional railguns

    Parker, J.V.

    1990-01-01

    Augmentation is a well-known technique for reducing the armature current and hence the armature power dissipation in a plasma armature railgun. In spite of the advantages, no large augmented railguns have been built, primarily due to the mechanical and electrical complexity introduce by the extra conductors required. It is possible to achieve some of the benefits of augmentation in conventional railgun by diverting a fraction {phi} of the input current through a shunt path at the muzzle of the railgun. In particular, the relation between force and armature current is the same as that obtained in an n-turn, series connected augmented railgun with n = 1/(1-{phi}). The price of this simplification is a reduction in electrical efficiency and some additional complexity in the external electrical system. Additions to the electrical system are required to establish the shunt current and to control its magnitude during projectile acceleration. The relationship between muzzle shunt augmentation and conventional series augmentation is developed and various techniques is developed and various techniques for establishing and controlling the shunt current are illustrated with a practical example. 5 refs., 8 figs., 2 tabs.

  1. Fabrication of capacitively-shunted superconducting qubits

    Yoder, Jonilyn L.; Gudmundsen, Theodore J.; Bolkhovsky, Vladimir; Welander, Paul B.; Gustavsson, Simon; Hover, David; Kerman, Andrew J.; Sears, Adam P.; Oliver, William D.

    2014-03-01

    Improvements in superconducting qubit coherence times and reproducibility have been demonstrated using capacitive shunting. In this study, we present methods for the preparation of both capacitively-shunted charge qubits (transmons) and capacitively-shunted flux qubits. Hybrid fabrication techniques were employed to combine high-quality-factor aluminum capacitive shunts with shadow-evaporated Josephson junctions, and the Josephson junctions were prepared using suspended-bridge germanium masks. We also will describe process testing results that were acquired to assess wafer-to-wafer reproducibility of our fabrication protocols. This research was funded in part by the Office of the Director of National Intelligence (ODNI), Intelligence Advanced Research Projects Activity (IARPA); and by the Assistant Secretary of Defense for Research and Engineering under Air Force Contract number FA8721-05-C-0002. All statements of fact, opinion or conclusions contained herein are those of the authors and should not be construed as representing the official views or policies of IARPA, the ODNI, or the U.S. Government.

  2. Train shunting at a workshop area

    Jacobsen, Per Munk; Pisinger, David

    2011-01-01

    We consider the problem of planning the shunting of train units at a railway workshop area. Before and after the maintenance check, a train unit is parked at a depository track. The problem is to schedule the trains to workshops and depot tracks in order to complete the repairs as soon as possible...

  3. Resting pulmonary haemodynamics and shunting: a comparison of sea-level inhabitants to high altitude Sherpas

    Foster, Glen E; Ainslie, Philip N; Stembridge, Mike; Day, Trevor A; Bakker, Akke; Lucas, Samuel J E; Lewis, Nia C S; MacLeod, David B; Lovering, Andrew T

    2014-01-01

    The incidence of blood flow through intracardiac shunt and intrapulmonary arteriovenous anastomoses (IPAVA) may differ between Sherpas permanently residing at high altitude (HA) and sea-level (SL) inhabitants as a result of evolutionary pressure to improve gas exchange and/or resting pulmonary haemodynamics. To test this hypothesis we compared sea-level inhabitants at SL (SL-SL; n = 17), during acute isocapnic hypoxia (SL-HX; n = 7) and following 3 weeks at 5050 m (SL-HA; n = 8 non-PFO subjects) to Sherpas at 5050 m (n = 14). , heart rate, pulmonary artery systolic pressure (PASP) and cardiac index (Qi) were measured during 5 min of room air breathing at SL and HA, during 20 min of isocapnic hypoxia (SL-HX; = 47 mmHg) and during 5 min of hyperoxia ( = 1.0; Sherpas only). Intracardiac shunt and IPAVA blood flow was evaluated by agitated saline contrast echocardiography. Although PASP was similar between groups at HA (Sherpas: 30.0 ± 6.0 mmHg; SL-HA: 32.7 ± 4.2 mmHg; P = 0.27), it was greater than SL-SL (19.4 ± 2.1 mmHg; P < 0.001). The proportion of subjects with intracardiac shunt was similar between groups (SL-SL: 41%; Sherpas: 50%). In the remaining subjects, IPAVA blood flow was found in 100% of subjects during acute isocapnic hypoxia at SL, but in only 4 of 7 Sherpas and 1 of 8 SL-HA subjects at rest. In conclusion, differences in resting pulmonary vascular regulation, intracardiac shunt and IPAVA blood flow do not appear to account for any adaptation to HA in Sherpas. Despite elevated pulmonary pressures and profound hypoxaemia, IPAVA blood flow in all subjects at HA was lower than expected compared to acute normobaric hypoxia. PMID:24396057

  4. 40 CFR 60.2918 - What happens during periods of startup, shutdown, and malfunction?

    2010-07-01

    ... 40 Protection of Environment 6 2010-07-01 2010-07-01 false What happens during periods of startup... of startup, shutdown, and malfunction? The emission limitations and operating limits apply at all times except during OSWI unit startups, shutdowns, or malfunctions. Performance Testing...

  5. 40 CFR 60.2120 - What happens during periods of startup, shutdown, and malfunction?

    2010-07-01

    ... 40 Protection of Environment 6 2010-07-01 2010-07-01 false What happens during periods of startup... 1, 2001 Emission Limitations and Operating Limits § 60.2120 What happens during periods of startup... during CISWI unit startups, shutdowns, or malfunctions. (b) Each malfunction must last no longer than...

  6. 40 CFR 63.2852 - What is a startup, shutdown, and malfunction plan?

    2010-07-01

    ... 40 Protection of Environment 12 2010-07-01 2010-07-01 true What is a startup, shutdown, and... Production Compliance Requirements § 63.2852 What is a startup, shutdown, and malfunction plan? You must...)(2) malfunction period, or the § 63.2850(c)(2) or (d)(2) initial startup period. The SSM plan...

  7. 40 CFR 60.2685 - What happens during periods of startup, shutdown, and malfunction?

    2010-07-01

    ... 40 Protection of Environment 6 2010-07-01 2010-07-01 false What happens during periods of startup... happens during periods of startup, shutdown, and malfunction? (a) The emission limitations and operating limits apply at all times except during CISWI unit startups, shutdowns, or malfunctions. (b)...

  8. 40 CFR 60.3025 - What happens during periods of startup, shutdown, and malfunction?

    2010-07-01

    ... 40 Protection of Environment 6 2010-07-01 2010-07-01 false What happens during periods of startup... during periods of startup, shutdown, and malfunction? The emission limitations and operating limits apply at all times except during OSWI unit startups, shutdowns, or malfunctions. Model...

  9. Platypnea-Orthodeoxia Syndrome: To Shunt or Not to Shunt, That is the Question.

    Klein, Michael R; Kiefer, Todd L; Velazquez, Eric J

    2016-06-01

    Platypnea-orthodeoxia syndrome is a rare disease defined by dyspnea and deoxygenation, induced by an upright position, and relieved by recumbency. Causes include shunting through a patent foramen ovale and pulmonary arteriovenous malformations. A 79-year-old woman experienced 2 syncopal episodes at rest and presented at another hospital. In the emergency department, she was hypoxic, needing 6 L/min of oxygen. Her chest radiograph showed nothing unusual. Transthoracic echocardiograms with saline microcavitation evaluation were mildly positive early after agitated-saline administration, suggesting intracardiac shunting. She was then transferred to our center. Right-sided heart catheterization revealed no oximetric evidence of intracardiac shunting while the patient was supine and had a low right atrial pressure. However, her oxygen saturation dropped to 78% when she sat up. Repeat transthoracic echocardiography while sitting revealed a dramatically positive early saline microcavitation-uptake into the left side of the heart. Transesophageal echocardiograms showed a patent foramen ovale, with right-to-left shunting highly dependent upon body position. The patient underwent successful percutaneous patent foramen ovale closure, and her oxygen supplementation was suspended. In patients with unexplained or transient hypoxemia in which a cardiac cause is suspected, it is important to evaluate shunting in both the recumbent and upright positions. In this syndrome, elevated right atrial pressure is not necessary for significant right-to-left shunting. Percutaneous closure, if feasible, is first-line therapy in these patients. PMID:27303248

  10. Encefalopatía hepática secundaria a la existencia de un shunt portosistémico tratada satisfactoriamente mediante radiología intervencionista Hepatic encephalophaty secondary to porto-systemic shunt satisfactorily treated with interventionist radiology

    L. Crespo

    2007-11-01

    Full Text Available La encefalopatía hepática es un estado reversible de alteración en la función cognitiva, que puede ocurrir en pacientes con enfermedad hepática aguda o crónica o shunts porto-sistémicos, en el que puede aparecer cualquiera de los signos neurológicos o psiquiátricos conocidos. Las sustancias nitrogenadas procedentes de la digestión intestinal alcanzan el cerebro sin la depuración que supone su paso por el hígado, debido a las derivaciones porto-sistémicas, y dan lugar a los signos característicos de la encefalopatía hepática. A continuación presentamos dos casos clínicos de pacientes con shunt porto-sistémicos, diagnosticados de encefalopatía hepática crónica recurrente refractaria al tratamiento médico convencional, tratados satisfactoriamente con embolización de dicho shunt mediante técnicas de radiología intervencionista.Hepatic encephalopathy is a reversible state of altered cognition that may occur in patients with acute or chronic liver disease or porto-systemic shunt, and in which known neurological or psychiatric signs may develop. Nitrogenated substances from intestinal digestion reach the brain without being cleared by their passage through the liver due to the presence of porto-systemic shunt. We report two cases of patients with porto-systemic shunt diagnosed with recurrent chronic hepatic encephalopathy refractory to conventional medical treatment. They were satisfactorily treated with shunt embolization using interventionist radiology techniques.

  11. Laparoscopy versus mini-laparotomy peritoneal catheter insertion of ventriculoperitoneal shunts: a systematic review and meta-analysis.

    He, Mingliang; Ouyang, Leping; Wang, Shengwen; Zheng, Meiguang; Liu, Anmin

    2016-09-01

    OBJECTIVE Ventriculoperitoneal (VP) shunt treatment is the main treatment method for hydrocephalus. The traditional operative approach for peritoneal catheter insertion is mini-laparotomy. In recent years, laparoscopy-assisted insertion has become increasingly popular. It seems likely that use of an endoscope could lower the incidence of shunt malfunction. However, there is no consensus about the benefits of laparoscopy-assisted peritoneal catheter insertion. METHODS A systematic search was performed using the PubMed, Embase, ScienceDirect, and Cochrane Library databases. A manual search for reference lists was conducted. The protocol was prepared according to the interventional systematic reviews of the Cochrane Handbook, and the article was written on the basis of the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analysis) guidelines. RESULTS Eleven observational trials and 2 randomized controlled trials were included. Seven operation-related outcome measures were analyzed, and 3 of these showed no difference between operative techniques. The results of the meta-analysis are as follows: in the laparoscopy group, the rate of distal shunt failure was lower (OR 0.41, 95% CI 0.25-0.67; p = 0.0003), the absolute effect is 7.11% for distal shunt failure, the number needed to treat is 14 (95% CI 8-23), operative time was shorter (mean difference [MD], -12.84; 95% CI -20.68 to -5.00; p = 0.001), and blood loss was less (MD -9.93, 95% CI -17.56 to -2.31; p = 0.01). In addition, a borderline statistically significant difference tending to laparoscopic technique was observed in terms of hospital stay (MD -1.77, 95% CI -3.67 to 0.13; p = 0.07). CONCLUSIONS To some extent, a laparoscopic insertion technique could yield a better prognosis, mainly because it is associated with a lower distal failure rate and shorter operative time, which would be clinically relevant. PMID:27581319

  12. Circadian malfunctions in depression - neurobiological and psychosocial approaches.

    Nechita, Florina; Pîrlog, Mihail Cristian; ChiriŢă, Anca Livia

    2015-01-01

    Depression leads to disturbances in physiological rhythms, which result in disturbances in circadian sleep-wake cycles, hormonal secretion patterns and fluctuations in mood, all of which can be objectively measured. These disturbances, which are associated with depression, can be also used to define depression. Beyond these "transversal" time-related symptoms, there are the "longitudinal" time-related symptoms, since depression evolves over a long period of time, with a profound impact on a person's life and is often associated with long-term psychosocial consequences (Mendlewicz, 2010). The circadian rhythm reflects an approximate 24-hour cycle in the biochemical, physiological and behavioral processes of living entities, which crucially influences human well-being and health. Increasing evidence from clinical and neurobiological research suggests that disrupted temporal organization impairs behavior, cognition, mood, sleep and social activity and may be implicated in mental disorders. It has been proposed that circadian malfunction is a major core feature of mood disorders, depression in particular. In depressed patients, circadian rhythms and homeostatic processes are disrupted, thereby affecting mood, sleep, activity and a variety of biological functions such as hormone secretion and body temperature (Hajak & Landgrebe, 2010). Sleep difficulties are among the most current symptoms in depressed patients. Insomnia is often the reason why depressed patients seek help and relief of sleep disturbance may encourage compliance with antidepressant treatment. Apart from the discomfort that sleep problems produce, they may lead to exhaustion, poor functioning and they are associated with an increase in suicide risk (Wilson et al., 2013). PMID:26662127

  13. Defective Homocysteine Metabolism: Potential Implications for Skeletal Muscle Malfunction

    Suresh C. Tyagi

    2013-07-01

    Full Text Available Hyperhomocysteinemia (HHcy is a systemic medical condition and has been attributed to multi-organ pathologies. Genetic, nutritional, hormonal, age and gender differences are involved in abnormal homocysteine (Hcy metabolism that produces HHcy. Homocysteine is an intermediate for many key processes such as cellular methylation and cellular antioxidant potential and imbalances in Hcy production and/or catabolism impacts gene expression and cell signaling including GPCR signaling. Furthermore, HHcy might damage the vagus nerve and superior cervical ganglion and affects various GPCR functions; therefore it can impair both the parasympathetic and sympathetic regulation in the blood vessels of skeletal muscle and affect long-term muscle function. Understanding cellular targets of Hcy during HHcy in different contexts and its role either as a primary risk factor or as an aggravator of certain disease conditions would provide better interventions. In this review we have provided recent Hcy mediated mechanistic insights into different diseases and presented potential implications in the context of reduced muscle function and integrity. Overall, the impact of HHcy in various skeletal muscle malfunctions is underappreciated; future studies in this area will provide deeper insights and improve our understanding of the association between HHcy and diminished physical function.

  14. Dc SQUIDs with asymmetric shunt resistors

    We have investigated asymmetrically shunted Nb/Al-AlOx/Nb dc SQUIDs. Simulations based on the coupled Langevin equations predict that the optimum energy resolution ε, and thus also the noise performance of such an asymmetric SQUID, can be 3-4 times better than that of its symmetric counterpart. While keeping the total resistance R identical to a comparable symmetric SQUID with R-1 = R1-1 + R2-1, we shunted only one of the two Josephson junctions with R = R1,2/2. Both types of SQUIDs were characterized with respect to their transport and noise properties at temperature T = 4.2 K, and we compared the experimental results with numerical simulations. Experiments yielded ε ∼ 32 ℎ for an asymmetric SQUID with an inductance L = 22 pH, whereas a comparable symmetric device achieved ε = 110 ℎ.

  15. 40 CFR 60.1220 - What happens to the emission limits during periods of startup, shutdown, and malfunction?

    2010-07-01

    ... during periods of startup, shutdown, and malfunction? 60.1220 Section 60.1220 Protection of Environment... Emission Limits § 60.1220 What happens to the emission limits during periods of startup, shutdown, and... waste combustion unit startup, shutdown, or malfunction. (b) Each startup, shutdown, or malfunction...

  16. Transjugular Intrahepatic Portosystemic Shunt Dysfunction: Concordance of Clinical Findings, Doppler Ultrasound Examination, and Shunt Venography

    Owen, Joshua M; Gaba, Ron Charles

    2016-01-01

    Objectives: The objective of this study was to evaluate the concordance between clinical symptoms, Doppler ultrasound (US), and shunt venography for the detection of stent-graft transjugular intrahepatic portosystemic shunt (TIPS) dysfunction. Materials and Methods: Forty-one patients (M:F 30:11, median age 55 years) who underwent contemporaneous clinical exam, Doppler US, and TIPS venography between 2003 and 2014 were retrospectively studied. Clinical symptoms (recurrent ascites or variceal bleeding) were dichotomously classified as present/absent, and US and TIPS venograms were categorized in a binary fashion as normal/abnormal. US abnormalities included high/low (>190 or 50 cm/s), absent flow, and return of antegrade intra-hepatic portal flow. Venographic abnormalities included shunt stenosis/occlusion and/or pressure gradient elevation. Clinical and imaging concordance rates were calculated. Results: Fifty-two corresponding US examinations and venograms were assessed. The median time between studies was 3 days. Forty of 52 (77%) patients were symptomatic, 33/52 (64%) US examinations were abnormal, and 20/52 (38%) TIPS venograms were abnormal. Concordance between clinical symptoms and TIPS venography was 48% (25/52), while the agreement between US and shunt venography was 65% (34/52). Clinical symptoms and the US concurred in 60% (31/52) of the patients. The sensitivity of clinical symptoms and US for the detection of venographically abnormal shunts was 80% (16/20) and 85% (17/20), respectively. Both clinical symptoms and the US had low specificity (25%, 8/32 and 50%, 16/32) for venographically abnormal shunts. Conclusion: Clinical findings and the US had low concordance rates with TIPS venography, with acceptable sensitivity but poor specificity. These findings suggest the need for improved noninvasive imaging methods for stent-graft TIPS surveillance.

  17. An expert system for sensor data validation and malfunction detection

    Nuclear power plant operation and monitoring in general is a complex task which requires a large number of sensors, alarms and displays. At any instant in time, the operator is required to make a judgment about the state of the plant and to react accordingly. During abnormal situations, operators are further burdened with time constraints. The possibility of an undetected faulty instrumentation line, adds to the complexity of operators' reasoning tasks. Failure of human operators to cope with the conceptual complexity of abnormal situations often leads to more serious malfunctions and further damages to plant (TMI-2 as an example). During these abnormalities, operators rely on the information provided by the plant sensors and associated alarms. Their usefulness however, is quickly diminished by their large number and the extremely difficult task of interpreting and comprehending the information provided by them. The need for an aid to assist the operator in interpreting the available data and diagnosis of problems is obvious. Recent work at the Ohio State University Laboratory of Artificial Intelligence Research (LAIR) and the nuclear engineering program has concentrated on the problem of diagnostic expert systems performance and their applicability to the nuclear power plant domain. There has also been concern about the diagnostic expert systems performance when using potentially invalid sensor data. Because of this research, an expert system has been developed that can perform diagnostic problem solving despite the existence of some conflicting data in the domain. This work has resulted in enhancement of a programming tool, that allows domain experts to create a diagnostic system that will be to some degree, tolerant of bad data while performing diagnosis. This expert system is described here

  18. Radiological evaluation of coronary artery-cardiac chamber shunt

    Matsunaga, Naofumi

    1987-09-01

    Coronary artery-cardiac chamber shunts were observed in 84 cases out of consecutive 1,126 cases in which coronary angiography was performed. This ''coronary artery-cardiac chamber shunt'' has no draining vein and contrast material directly escapes into the cardiac chamber, which is different from the so-called ''coronary arterio-venous fistula''. The angiographic features of coronary artery-cardiac chamber shunt were classified into three types; Type I (57 cases): Endocardium is diffusely opacified on distole, and contrast material escapes into the cardiac chamber on systole. Type II (13 cases): A small localized direct coronary artery-cardiac chamber shunt. Type III (20 cases): Contrast material escapes into the cardiac chamber in the area of mural thrombus of the left atrium or left ventricle. It is speculated that type I shunt is due to persistent arterio-sinusoidal vessel, and type II shunt is due to persistent arterio-luminal vessel. Type I and II shunts were observed in hypertrophic cardiomyopathy with high incidence (42.4 %). In hypertrophic cardiomyopathy, the degree of shunts was not correlated with the degree of the ventricular wall thickening. These shunts were not also correlated with the presence or absence of myocardial squeezing. These facts suggest that the shunts may be due to the abnormality of the microcirculation of the myocardium. Type III shunt was observed in the mural thrombus in the left ventricle (7 cases), left atrial thrombus (12 cases) and verruca of the mitral valve (1 case). Angiographic features of these shunts are described, and their pathophysiological significance is discussed.

  19. Effect of peritoneo-venous shunt on portal pressure.

    Samanta, A K; Leevy, C. M.

    1989-01-01

    The cause of variceal bleed after a peritoneo-venous shunt is not known. Portal haemodynamic consequences of a peritoneo-venous shunt are poorly understood. The most critical period after a peritoneo-venous shunt is the early postoperative period when rapid mobilisation of peritoneal fluid occurs. Serial changes in the portal pressure during the early postoperative period have not been recorded. In the present study preoperative wedge hepatic vein (WHV), right atrial (RA) and pulmonary capill...

  20. Medulloblastoma: seeding of VP shunt tract and peritoneum

    David Pettersson; Schmitz, Kelli R.; Pollock, Jeffrey M.; Katharine L. Hopkins

    2012-01-01

    We report on a 5-year-old boy with seeding of the peritoneum and a ventriculoperitoneal shunt tract by anaplastic medulloblastoma. The role of ventriculoperitoneal shunting in the spread of primary central nervous system tumors has been controversial. In the case reported here, the unique distribution of tumor implants on ultrasound and multiplanar computed tomography gives further credence to the argument that ventriculoperitoneal shunting is a pathway for extraneural metastases of primary c...

  1. SUBGALEAL MIGRATION OF THE DISTAL CATHETER OF A VENTRICULOPERITONEAL SHUNT

    Vinayak

    2015-08-01

    Full Text Available INTRODUCTION : Migration is a rare complication of venticuloperitoneal shunts and is thought to be associated with the "memory" of the plastic tubing and the windlass effect of neck flexion and extension. CASE PRESENTATION: A 11 months infant was bought to the hospital presenting with complaints of vomitin g, fever, drowsiness and progressive swelling on previous operated site at right occipital region with history of previous ventriculoperitoneal shunt surgery. CONCLUSIONS: Migration of inserted shunt system in subgaleal space is a rarity

  2. 40 CFR 1045.110 - How must my engines diagnose malfunctions?

    2010-07-01

    ... color except red. Visible malfunction indicators must display “Check Engine,” “Service Engine Soon,” or... engine operation. (d) Store trouble codes in computer memory. Record and store in computer memory...

  3. Semi-shunt field emission in electronic devices

    Karpov, V. G.; Shvydka, Diana

    2014-08-01

    We introduce a concept of semi-shunts representing needle shaped metallic protrusions shorter than the distance between a device electrodes. Due to the lightening rod type of field enhancement, they induce strong electron emission. We consider the corresponding signature effects in photovoltaic applications; they are: low open circuit voltages and exponentially strong random device leakiness. Comparing the proposed theory with our data for CdTe based solar cells, we conclude that stress can stimulate semi-shunts' growth making them shunting failure precursors. In the meantime, controllable semi-shunts can play a positive role mitigating the back field effects in photovoltaics.

  4. Semi-shunt field emission in electronic devices

    Karpov, V. G., E-mail: victor.karpov@utoledo.edu [Department of Physics and Astronomy, University of Toledo, Toledo, Ohio 43606 (United States); Shvydka, Diana, E-mail: diana.shvydka@utoledo.edu [Department of Radiation Oncology, University of Toledo, Toledo, Ohio 43606 (United States)

    2014-08-04

    We introduce a concept of semi-shunts representing needle shaped metallic protrusions shorter than the distance between a device electrodes. Due to the lightening rod type of field enhancement, they induce strong electron emission. We consider the corresponding signature effects in photovoltaic applications; they are: low open circuit voltages and exponentially strong random device leakiness. Comparing the proposed theory with our data for CdTe based solar cells, we conclude that stress can stimulate semi-shunts' growth making them shunting failure precursors. In the meantime, controllable semi-shunts can play a positive role mitigating the back field effects in photovoltaics.

  5. A compact, coaxial shunt current diagnostic for X pinches

    Wang, Liangping; Zhang, Jinhai; Li, Mo; Zhang, Xinjun; Zhao, Chen; Zhang, Shaoguo

    2015-08-01

    A compact coaxial shunt was applied in X-pinches experiments on Qiangguang pulsed power generator. The coaxial shunt was designed to have a compact construction for smaller inductance and more, for conveniently assembling upon the X pinch load structure. The coaxial shunt is also a cheap current probe and was easily built by research groups. The shunt can monitor a 100 kA high current with a 100 ns rise time. The calibration results showed that the probe used in the experiments has a resistance of 3.2 mΩ with an uncertainty of 3%, and its response time to the step signal is less than 7 ns.

  6. Superconducting fault current-limiter with variable shunt impedance

    Llambes, Juan Carlos H; Xiong, Xuming

    2013-11-19

    A superconducting fault current-limiter is provided, including a superconducting element configured to resistively or inductively limit a fault current, and one or more variable-impedance shunts electrically coupled in parallel with the superconducting element. The variable-impedance shunt(s) is configured to present a first impedance during a superconducting state of the superconducting element and a second impedance during a normal resistive state of the superconducting element. The superconducting element transitions from the superconducting state to the normal resistive state responsive to the fault current, and responsive thereto, the variable-impedance shunt(s) transitions from the first to the second impedance. The second impedance of the variable-impedance shunt(s) is a lower impedance than the first impedance, which facilitates current flow through the variable-impedance shunt(s) during a recovery transition of the superconducting element from the normal resistive state to the superconducting state, and thus, facilitates recovery of the superconducting element under load.

  7. Unidirectional valve malfunction by the breakage or malposition of disc - two cases report -

    Lee, Chol; Lee, Kyu Chang; Kim, Hye Young; Kim, Mi Na; Choi, Eun Kyung; Kim, Ji-Sub; Lee, Won Sang; Lee, Myeong Jong; Kim, Hyung Tae

    2013-01-01

    Malfunction of the unidirectional valve in a breathing circuit system may cause hypercapnia from the rebreathing of expired gas, ventilation failure, and barotrauma. Capnography is a useful method for monitoring the integrity of the unidirectional valve. We experienced two cases of malfunction of a unidirectional valve which caused leakage and reverse flow, diagnosed early as a change of the capnographic waveform. One case was caused by expiratory unidirectional valve breakage. The other was ...

  8. On the malfunction of disk-type induction relay under seismic condition

    This paper deals with the malfunction of disk-type induction relay. Equations of motion for rotational movement of induction relay was formulated and the dynamic behavior was simulated under various kind of exciting conditions. Experimental verification was also performed using two dimensional shaker table for some actual relays. Sufficient agreement was recognized between experimental and analytical results and consequently the most critical reason to cause the malfunction was pointed out. (orig.)

  9. Long-Term Neuropsychological Sequelae in HIV-Seronegative Cryptococcal Meningoencephalitis Patients with and without Ventriculoperitoneal Shunts: A Cine MRI Study

    Meng-Hsiang Chen

    2015-01-01

    Full Text Available Background. Hydrocephalus in cryptococcal meningoencephalitis is most commonly managed with a ventriculoperitoneal shunt. This study applied cine magnetic resonance imaging (MRI to evaluate initial disease severity on long-term cerebrospinal fluid (CSF flow dynamics and associated neuropsychological sequelae in cryptococcal meningoencephalitis patients with and without ventriculoperitoneal shunts. Methods. Eighteen human immunodeficiency virus-seronegative cryptococcal meningoencephalitis patients (10 with shunts versus 8 without shunts were compared with 32 age- and sex-matched healthy volunteers. All subjects underwent complete neurologic examination and neuropsychological testing. Cine MRI was conducted to evaluate CSF flow parameters. Initial CSF laboratory analysis and imaging findings were correlated with present CSF flow parameters and neuropsychological scores. Results. Patients without shunts had higher average flow than controls, suggesting chronic hydrocephalus. Initial Evans ratios and CSF glucose levels were associated with CSF peak velocity and flow. Worsening CSF flow parameters correlated with decreased neuropsychological performance. Conclusions. CSF flow parameter differences between the cryptococcal meningoencephalitis patients both with and without ventriculoperitoneal shunts could be detected by cine MRI and correlated with acute stage disease severity and chronic stage neuropsychological results. Cine MRI is useful for assessing the chronic hydrocephalus that may lead to neuropsychological deficits in cryptococcal meningoencephalitis patients.

  10. Embolization of severe arterioportal shunts in the patients with hepatocellular carcinoma : safety and influence on patient survival

    Lee, Deok Hee; Yoon, Hyun Ki; Song, Ho Young; Kim, Gab Choul; Hwang, Jae Cheol; Sung, Kyu Bo [Asan Medical Center, Ulsan Univ. College of Medicine, Ulsan (Korea, Republic of)

    1999-12-01

    To evaluate the safety and the influence of embolization of severe arterioportal shunts, and the effect of the procedure on the survival rate of patients with hepatocellular carcinoma combined with portal vein tumor thrombosis. This study involved a total of 54 patients with hepatocellular carcinoma in whom hepatic arteriography revealed severe arterioportal shunt. From among this total, 34 patients (embolization group) underwent chemoinfusion after shunt embolization, while 19 (control group) underwent chemoinfusion only. The embolic materials included PVA particles and /or Gelfoam pieces. The frequency of postem-bolization symptoms (Chi-squared test) and changes in laboratory values (paired t-test) were compared between the two groups, and shunt improvement was also evaluated. Patient survival was tested using the Kaplan-Meier method. Fever and RUQ pain were more frequent in the embolization group (p<0.001). The complications of embolization included severe postembolization syndrome (n=1), acute hepatic failure (n=2), hepatic infarction (n=1), and sepsis (n=1). There were no significant changes in laboratory values. Among the 28 patients (24 of embolization group and four of control group) who underwent follow-up angiography, arterioportal shunt became less severe or disappeared in ten of the embolization group. For the embolization and control groups, the mean survival interval was 29.5{+-}5.4 weeks and 10.3{+-}3.1 weeks (p=0.0002), respectively. The best results were seen in the PVA particle group (p=0.01). The embolization of severe arterioportal shunts is relatively safe and increases patient survival rate.

  11. Embolization of severe arterioportal shunts in the patients with hepatocellular carcinoma : safety and influence on patient survival

    To evaluate the safety and the influence of embolization of severe arterioportal shunts, and the effect of the procedure on the survival rate of patients with hepatocellular carcinoma combined with portal vein tumor thrombosis. This study involved a total of 54 patients with hepatocellular carcinoma in whom hepatic arteriography revealed severe arterioportal shunt. From among this total, 34 patients (embolization group) underwent chemoinfusion after shunt embolization, while 19 (control group) underwent chemoinfusion only. The embolic materials included PVA particles and /or Gelfoam pieces. The frequency of postem-bolization symptoms (Chi-squared test) and changes in laboratory values (paired t-test) were compared between the two groups, and shunt improvement was also evaluated. Patient survival was tested using the Kaplan-Meier method. Fever and RUQ pain were more frequent in the embolization group (p<0.001). The complications of embolization included severe postembolization syndrome (n=1), acute hepatic failure (n=2), hepatic infarction (n=1), and sepsis (n=1). There were no significant changes in laboratory values. Among the 28 patients (24 of embolization group and four of control group) who underwent follow-up angiography, arterioportal shunt became less severe or disappeared in ten of the embolization group. For the embolization and control groups, the mean survival interval was 29.5±5.4 weeks and 10.3±3.1 weeks (p=0.0002), respectively. The best results were seen in the PVA particle group (p=0.01). The embolization of severe arterioportal shunts is relatively safe and increases patient survival rate

  12. Neurogenic pulmonary edema due to ventriculo-atrial shunt dysfunction: a case report

    Ana Sofia Cruz

    2016-04-01

    Full Text Available ABSTRACT BACKGROUND AND OBJECTIVES: Pulmonary edema is caused by the accumulation of fluid within the air spaces and the interstitium of the lung. Neurogenic pulmonary edema is a clinical syndrome characterized by the acute onset of pulmonary edema following a significant central nervous system insult. It may be a less-recognized consequence of raised intracranial pressure due to obstructive hydrocephalus by blocked ventricular shunts. It usually appears within minutes to hours after the injury and has a high mortality rate if not recognized and treated appropriately. CASE REPORT: We report a patient with acute obstructive hydrocephalus due to ventriculo-atrial shunt dysfunction, proposed to urgent surgery for placement of external ventricular drainage, who presented with neurogenic pulmonary edema preoperatively. She was anesthetized and supportive treatment was instituted. At the end of the procedure the patient showed no clinical signs of respiratory distress, as prompt reduction in intracranial pressure facilitated the regression of the pulmonary edema. CONCLUSIONS: This report addresses the importance of recognition of neurogenic pulmonary edema as a possible perioperative complication resulting from an increase in intracranial pressure. If not recognized and treated appropriately, neurogenic pulmonary edema can lead to acute cardiopulmonary failure with global hypoperfusion and hypoxia. Therefore, awareness of and knowledge about the occurrence, clinical presentation and treatment are essential.

  13. Memory and selective learning in children with spina bifida-myelomeningocele and shunted hydrocephalus: A preliminary study

    Vachha Behroze

    2005-11-01

    Full Text Available Abstract Background Selective learning is the ability to select items of relevance from among less important items. Limited evidence exists regarding the efficiency with which children with spina bifida-myelomeningocele and shunted hydrocephalus (SB/SH are able to learn information. This report describes initial data related to components of learning and metacognitive skills in children with SB/SH. Methods Twenty six children with SB/SH and 26 controls (age: 7 – 16 y with average intelligence, and monolingual English-speaking backgrounds participated in the study. Exclusion criteria for the SB/SH group were: prior history of shunt infection, history of seizure or shunt malfunction within the previous three months, prior diagnoses of attention disorders and/or clinical depression. Children were presented lists of words with equal exemplars each of two distinct semantic categories (e.g. fruits, animals, and told to make as high a score as possible by learning the words. The value of the words was designated by category membership (e.g. animals = low value; fruits = high value. The total number of words learned across three learning trials was used to determine memory span. Selective learning efficiency (SLE was computed as the efficiency with which items of greater value were selectively learned across three trials. Results Children with SB/SH did worse than controls on memory span (P Conclusion Success in school is often dependent on the ability to recall important facts selectively and ignore less important information. Children with SB/SH in our study had a poor memory span and were unable to monitor and report an efficient and workable metacognitive strategy required to remember a list of words. Preliminary findings may begin to explain our previous clinical and research findings wherein children with SB/SH often focus on extraneous details, but demonstrate difficulty remembering the main gist of a story/event.

  14. Usefulness of Transjugular Intrahepatic Portosystemic Shunt in the Management of Bleeding Ectopic Varices in Cirrhotic Patients

    Purpose. To evaluate the safety and efficacy of transjugular intrahepatic portosystemic shunt (TIPS) in the control of bleeding from ectopic varices. Methods. From 1995 to 2004, 24 cirrhotic patients, bleeding from ectopic varices, mean age 54.5 years (range 15-76 years), were treated by TIPS. The etiology of cirrhosis was alcoholic in 13 patients and nonalcoholic in 11 patients. The location of the varices was duodenal (n = 5), stomal (n = 8), ileocolic (n = 6), anorectal (n = 3), umbilical (n = 1), and peritoneal (n 1). Results. TIPS controlled the bleeding in all patients and induced a decrease in the portacaval gradient from 19.7 ± 5.4 to 6.4 ± 3.1 mmHg. Postoperative complications included self-limited intra-abdominal bleeding (n = 2), self-limited hemobilia (n = 1), acute thrombosis of the shunt (n = 1), and bile leak treated by a covered stent (n = 1). Median follow-up was 592 days (range 28-2482 days). Rebleeding occurred in 6 patients. In 2 cases rebleeding was observed despite a post-TIPS portacaval gradient lower than 12 mmHg and was controlled by variceal embolization; 1 patient underwent surgical portacaval shunt and never rebled; in 3 patients rebleeding was related to TIPS stenosis and treated with shunt dilatation with addition of a new stent. The cumulative rate of rebleeding was 23% and 31% at 1 and 2 years, respectively. One- and 2-year survival rates were 80% and 76%, respectively. Conclusion. The present series demonstrates that bleeding from ectopic varices, a challenging clinical problem, can be managed safely by TIPS placement with low rebleeding and good survival rates

  15. Epidural hematoma after ventriculoperitoneal shunt surgery: report of two cases

    PEREIRA CARLOS UMBERTO

    1998-01-01

    Full Text Available Ventriculoperitoneal shunt operations represent the most used choice for treating hydrocephalus, although some related complications have been reported. Due to its rarity, potential dangers, and mortality rate, we present two cases of epidural hematoma following ventriculoperitoneal shunt, discussing its pathophysiology and prophylaxis.

  16. Evaluation of Blalock-Taussig shunts using magnetic resonance imaging

    Four patients aged 3 to 18 months (mean 13 months) with a total of five Blalock-Taussig shunts (BT shunts; two were original BT shunts and three were modified BT shunts using GOLASKI grafts) underwent evaluation by ECG-gated magnetic resonance imaging. There were two cases with pulmonary atresia with intact ventricular septum, one with double outlet right ventricle with pulmonary stenosis and one with tetralogy of Fallot with pulmonary atresia who underwent bilateral BT shunts. At the time of study, an auscultory shunt murmur was audible in all patients. The magnetic resonance images were obtained with a Picker International Vista MR with a superconducting magnet operating at 0.5 Tesla. A spin echo sequence (echo time 40 msec) was used. All patients were placed within a 30 cm head coil radio antenna and sedated with chloral hydrate or diazepam. Four of 5 shunts were imaged on both coronal sections and sagittal sections during enddiastole. And there was no signal within the grafts. When the velocity of blood flow is beyond the cutoff velocity, the signal intensity of flowing blood is near background level. So we judged these grafts were patient. Our results showed that MRI was a very useful noninvasive method for evaluation of BT shunts. (author)

  17. Evaluation of Blalock-Taussig shunts using magnetic resonance imaging

    Okajima, Yoshitomo; Tashima, Kazuyuki; Terai, Masaru; Niwa, Koichirou.

    1988-10-01

    Four patients aged 3 to 18 months (mean 13 months) with a total of five Blalock-Taussig shunts (BT shunts; two were original BT shunts and three were modified BT shunts using GOLASKI grafts) underwent evaluation by ECG-gated magnetic resonance imaging. There were two cases with pulmonary atresia with intact ventricular septum, one with double outlet right ventricle with pulmonary stenosis and one with tetralogy of Fallot with pulmonary atresia who underwent bilateral BT shunts. At the time of study, an auscultory shunt murmur was audible in all patients. The magnetic resonance images were obtained with a Picker International Vista MR with a superconducting magnet operating at 0.5 Tesla. A spin echo sequence (echo time 40 msec) was used. All patients were placed within a 30 cm head coil radio antenna and sedated with chloral hydrate or diazepam. Four of 5 shunts were imaged on both coronal sections and sagittal sections during enddiastole. And there was no signal within the grafts. When the velocity of blood flow is beyond the cutoff velocity, the signal intensity of flowing blood is near background level. So we judged these grafts were patient. Our results showed that MRI was a very useful noninvasive method for evaluation of BT shunts.

  18. Flexural waves focusing through shunted piezoelectric patches

    Yi, K.; Collet, M.; Ichchou, M.; Li, L.

    2016-07-01

    In this paper, we designed and analyzed a piezo-lens to focus flexural waves in thin plates. The piezo-lens is comprised of a host plate and piezoelectric arrays bonded on the surfaces of the plate. The piezoelectric patches are shunted with negative capacitance circuits. The effective refractive indexes inside the piezo-lens are designed to fit a hyperbolic secant distribution by tuning the negative capacitance values. A homogenized model of a piezo-mechanical system is adopted in the designing process of the piezo-lens. The wave focusing effect is studied by the finite element method. Numerical results show that the piezo-lens can focus flexural waves by bending their trajectories, and is effective in a large frequency band. The piezo-lens has the ability to focus flexural waves at different locations by tuning the shunting negative capacitance values. The piezo-lens is shown to be effective for flexural waves generated by different types of sources.

  19. Self-expanding stents in transjugular intrahepatic portosystemic shunt: experience with nitinol Strecker stents.

    Rossi, P; Bezzi, M; Salvatori, F M; Broglia, L; Maccioni, F; Pizzi, G; Abbondanza, S; Bonomo, G

    1996-01-01

    The aim of our study was to evaluate the performance and efficacy of a new self-expanding stent (nitinol Strecker stent) in the transjugular intrahepatic portosystemic shunt (TIPS) procedure. We have successfully placed 64 nitinol Strecker stents in 48 patients. The average portosystemic gradient decreased from 22 to 11 mm Hg. Balloon dilatation was necessary in 12 of 35 angiographically controlled cases at 5 days (34%), because of incomplete stent expansion, small thrombi within the stent or obstruction. At 1-6 months stent malfunctions occurred in 8 of 23 patients who underwent control angiography (34%) and at 6-24 months in 6 of 7 patients (85%). Rebleeding occurred in 2 of 39 patients (follow-up > 1 month) (5%) and temporary crises of de novo encephalopathy were observed in 11 of 48 patients (23%). Refractory ascites completely resolved in 4 of 6 patients (66%) and improved in the remaining 2 cases. Compared with other self-expanding stents, nitinol Strecker stents seem to be equally effective in TIPS; no increase in complication rate was observed, either clinical or stent-related. PMID:8934143

  20. The influence of automation malfunctions and interface design on operator performance. The HCA-2001 experiment

    Skjerve, Ann Britt Miberg; Strand, Stine; Saarni, Ray; Skraaning, Gyrd Jr.

    2002-08-15

    This report presents the study plan and results of the Human Centred Automation 2001 experiment. The experiment was designed as a close follow-up of the HCA-2000 experiment, and the purpose was thus to examine how operators handle two types of automation malfunctions when working from interfaces that contain either explicit or implicit information about the automatic system. The experiment was carried out in the Nokia Research Simulator in HAMMLAB, and a total of 18 licensed operators from the Loviisa NPP participated. The experimental design was a Randomised Block Factorial-223 design, comprised by automation malfunction type with two manipulated levels, automation information (AIP) presentation type with two manipulated levels, and scenario period with three levels. The automation malfunction types were termed component malfunctions and strategy malfunctions, in which the first type referred to automation slips, i.e. failure in execution, and the latter type referred to automation mistakes, i.e. failure in planning. The AIP types were termed conventional AIP interface and experimental AIP interface, where the latter provided explicit verbal and graphical information about the automatic system. Some alterations were made with regard to both the scenario design and the provision of verbal feedback compared to the HCA-2000 experiment. The hypotheses were specified with reference to a SImple Model of Operator Activity (SIMOA), developed within the HCA-program and thoroughly accounted for in this report. SIMOA constitutes a cyclical model and refers to schema theory. The hypotheses stating that the operators would correctly handle component malfunctions faster than strategy malfunctions, and that workload would be lower, and situation awareness, trust in automation, and quality of cooperation would be higher when component rather than strategy malfunctions occurred, was not supported by the results. However, the hypotheses that operators would correctly handle

  1. The influence of automation malfunctions and interface design on operator performance. The HCA-2001 experiment

    This report presents the study plan and results of the Human Centred Automation 2001 experiment. The experiment was designed as a close follow-up of the HCA-2000 experiment, and the purpose was thus to examine how operators handle two types of automation malfunctions when working from interfaces that contain either explicit or implicit information about the automatic system. The experiment was carried out in the Nokia Research Simulator in HAMMLAB, and a total of 18 licensed operators from the Loviisa NPP participated. The experimental design was a Randomised Block Factorial-223 design, comprised by automation malfunction type with two manipulated levels, automation information (AIP) presentation type with two manipulated levels, and scenario period with three levels. The automation malfunction types were termed component malfunctions and strategy malfunctions, in which the first type referred to automation slips, i.e. failure in execution, and the latter type referred to automation mistakes, i.e. failure in planning. The AIP types were termed conventional AIP interface and experimental AIP interface, where the latter provided explicit verbal and graphical information about the automatic system. Some alterations were made with regard to both the scenario design and the provision of verbal feedback compared to the HCA-2000 experiment. The hypotheses were specified with reference to a SImple Model of Operator Activity (SIMOA), developed within the HCA-program and thoroughly accounted for in this report. SIMOA constitutes a cyclical model and refers to schema theory. The hypotheses stating that the operators would correctly handle component malfunctions faster than strategy malfunctions, and that workload would be lower, and situation awareness, trust in automation, and quality of cooperation would be higher when component rather than strategy malfunctions occurred, was not supported by the results. However, the hypotheses that operators would correctly handle

  2. A model based diagnostic system for the identification of malfunctioning components using a constraint propagation paradigm

    A commonly recognized failing of traditional rule-based diagnostic expert systems is the inability to recognize problems outside the range of expertise. In turn, the capability of such expert systems is limited to well-known problems. Contrary to the traditional approach, a model-based system has a potential to diagnose unexpected malfunctions. In this paper, a model-based diagnostic system for the isolation of malfunctioning components using constraint propagation paradigm - the CBDS, the Constraint Based Diagnostic System - is presented. The CBDS consists of (1) symbolic representation of plant model as a knowledge base, and (2) constraint propagation paradigm as a diagnostic inference engine. In the CBDS, a plant model contains information about intended behaviour of components that are organized in a component model library, as well as information about how the components are interconnected. As a diagnostic inference engine, the CBDS uses the general idea of model-based diagnosis to identify malfunctioning components. (author). 15 refs, 8 figs

  3. A plasma polymerization technique to overcome cerebrospinal fluid shunt infections

    Prosthetic devices, mainly shunts, are frequently used for temporary or permanent drainage of cerebrospinal fluid. The pathogenesis of shunt infection is a very important problem in modern medicine and generally this is characterized by staphylococcal adhesion to the cerebrospinal fluid shunt surfaces. In this paper, the prevention of the attachment of test microorganism Staphylococcus epidermidis on the cerebrospinal fluid shunt surfaces by 2-hydroxyethylmethacrylate (HEMA) precursor modification in the plasma polymerization system, is reported. Different plasma polymerization conditions (RF discharge power 10-20-30 W, exposure time 5-10-15 min) were employed during the surface modification. The surface chemistry and topology of unmodified and modified shunts was characterized by x-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and atomic force microscopy (AFM). Also, static contact angle measurements were performed to state the change of surface hydrophilicity. All samples were tested in vitro with Staphylococcus epidermidis. A plasma-polymerized HEMA film (PP HEMA) was found to be an alternative simple method to decrease the microorganism attachment and create bacterial anti-fouling surfaces. The attachment of the model microorganism Staphylococcus epidermidis on the shunt surface modified by PP HEMA at 20 W and 15 min was reduced 62.3% if compared to the unmodified control surface of the shunt

  4. Portosystemic Shunt Surgery in Patients with Idiopathic Noncirrhotic Portal Hypertension.

    Karagul, Servet; Yagci, Mehmet Ali; Tardu, Ali; Ertugrul, Ismail; Kirmizi, Serdar; Sumer, Fatih; Isik, Burak; Kayaalp, Cuneyt; Yilmaz, Sezai

    2016-01-01

    BACKGROUND Idiopathic noncirrhotic portal hypertension (INCPH) is a rare disease characterized by increased portal venous pressure in the absence of cirrhosis and other causes of liver diseases. The aim of the present study was to present our results in using portosystemic shunt surgery in patients with INCPH. MATERIAL AND METHODS Patients who had been referred to our Liver Transplantation Institute for liver transplantation and who had undergone surgery from January 2010 to December 2015 were retrospectively analyzed. Patients with INCPH who had undergone portosystemic shunt procedure were included in the study. Age, sex, symptoms and findings, type of portosystemic shunt, and postoperative complications were assessed. RESULTS A total of 1307 patients underwent liver transplantation from January 2010 to December 2015. Eleven patients with INCPH who did not require liver transplantation were successfully operated on with a portosystemic shunt procedure. The mean follow-up was 30.1±19 months (range 7-69 months). There was no mortality in the perioperative period or during the follow-up. Two patients underwent surgery again due to intra-abdominal hemorrhage; one had bleeding from the surgical site except the portacaval anastomosis and the other had bleeding from the h-graft anastomosis. No patient developed encephalopathy and no patient presented with esophageal variceal bleeding after portosystemic shunt surgery. Shunt thrombosis occurred in 1 patient (9.9%). Only 1 patient developed ascites, which was controlled medically. CONCLUSIONS Portosystemic shunt surgery is a safe and effective procedure for the treatment of patients with INCPH. PMID:27194018

  5. Muzzle shunt augmentation of conventional railguns

    Parker, J.V. (Los Alamos National Lab., NM (United States). Physics Div.)

    1991-01-01

    This paper reports on augmentation which is a technique for reducing the armature current and hence the armature power dissipation in a plasma armature railgun. In spite of the advantages, no large augmented railguns have been built, primarily due to the mechanical and electrical complexity introduced by the extra conductors required. it is possible to achieve some of the benefits of augmentation in a conventional railgun by diverting a fraction {phi} of the input current through a shunt path at the muzzle of the railgun. In particular, the relation between force and armature current is the same as that obtained in an n-turn, series-connected augmented railgun with n = 1/(1 {minus} {phi}). The price of this simplification is a reduction in electrical efficiency and some additional complexity in the external electrical system.

  6. CONTROLLED SHUNT REACTORS FOR ELECTRIC NETWORKS

    Dolgopolov A.G.,

    2011-12-01

    Full Text Available The article presents results of the research and design of controlled shunt alternative current reactors (CSR. The analysis of domestic and foreign experience of the development and deployment of CSR is performed, the effectiveness of their applications in power systems is assessed and results of the tests of samples CSR-220 kV and above are shown. Constructive features of CSR circuit are described; technical characteristics of the CSR-220, 500 kV are given. The prospects for widespread introduction of CSR for the control of power systems regimes are shown. The application of CSR in combination with other control devices such as FACTS allows, based on high-voltage lines of high capacity, creating controlled transmission lines of new generation, which corresponds to all necessary requirements with time-developing power systems and its associations.

  7. An experimental study of emission and combustion characteristics of marine diesel engine with fuel pump malfunctions

    Presented paper shows the results of the laboratory study on the relation between the chosen malfunctions of a fuel pump and the exhaust gas composition of the marine engine. The object of research is a laboratory four-stroke diesel engine, operated at a constant speed. During the research over 50 parameters were measured with technical condition of the engine recognized as “working properly” and with simulated fuel pump malfunctions. Considered malfunctions are: fuel injection timing delay and two sets of fuel leakages in the fuel pump of one engine cylinder. The results of laboratory research confirm that fuel injection timing delay and fuel leakage in the fuel pump cause relatively small changes in thermodynamic parameters of the engine. Changes of absolute values are so small they may be omitted by marine engines operators. The measuring of the exhaust gas composition shows markedly affection with simulated malfunctions of the fuel pump. Engine operation with delayed fuel injection timing in one cylinder indicates CO2 emission increase and NOx emission decreases. CO emission increases only at high the engine loads. Fuel leakage in the fuel pump causes changes in CO emission, the increase of CO2 emission and the decrease of NOx emission. - Highlights: •Chosen malfunctions of the fuel injection pump of marine engine are simulated. •Changes of thermodynamic parameters of marine engine are analyzed. •Changes of CO, CO2 and NOx emission characteristics of marine engine are analyzed. •Injection pump malfunctions take significant changes in emission characteristics

  8. Evaluation of the use of automatic exposure control and automatic tube potential selection in low-dose cerebrospinal fluid shunt head CT

    Wallace, Adam N.; Bagade, Swapnil; Chatterjee, Arindam; Hicks, Brandon; McKinstry, Robert C. [Barnes Jewish Hospital, Mallinckrodt Institute of Radiology, St. Louis, MO (United States); Washington University School of Medicine, St. Louis, MO (United States); Vyhmeister, Ross [Washington University School of Medicine, St. Louis, MO (United States); Ramirez-Giraldo, Juan Carlos [Siemens Healthcare, Malvern, PA (United States)

    2015-03-17

    Cerebrospinal fluid shunts are primarily used for the treatment of hydrocephalus. Shunt complications may necessitate multiple non-contrast head CT scans resulting in potentially high levels of radiation dose starting at an early age. A new head CT protocol using automatic exposure control and automated tube potential selection has been implemented at our institution to reduce radiation exposure. The purpose of this study was to evaluate the reduction in radiation dose achieved by this protocol compared with a protocol with fixed parameters. A retrospective sample of 60 non-contrast head CT scans assessing for cerebrospinal fluid shunt malfunction was identified, 30 of which were performed with each protocol. The radiation doses of the two protocols were compared using the volume CT dose index and dose length product. The diagnostic acceptability and quality of each scan were evaluated by three independent readers. The new protocol lowered the average volume CT dose index from 15.2 to 9.2 mGy representing a 39 % reduction (P < 0.01; 95 % CI 35-44 %) and lowered the dose length product from 259.5 to 151.2 mGy/cm representing a 42 % reduction (P < 0.01; 95 % CI 34-50 %). The new protocol produced diagnostically acceptable scans with comparable image quality to the fixed parameter protocol. A pediatric shunt non-contrast head CT protocol using automatic exposure control and automated tube potential selection reduced patient radiation dose compared with a fixed parameter protocol while producing diagnostic images of comparable quality. (orig.)

  9. Malfunction of the inner ear is the most frequent cause of dizziness

    Klokker, Mads; Vesterhauge, Søren

    2013-01-01

    Half of all dizziness patients suffer from a malfunction of the inner ear and benign paroxysmal positional vertigo causes 25-30% of these malfunctions. During the latest two decades new vestibular test equipment has been developed and has made it possible to refine the vestibular diagnoses...... and consequently treat patients more efficiently. This brief overview describes the benefit of Epley's Omniax Chair, video head impulse tests and the Vestibular Autorotation Test. The need for vestibular rehabilitation programmes and for a closer collaboration between physicians and the social authorities...

  10. Clopidogrel in infants with systemic-to-pulmonary-artery shunts

    Wessel, David L; Berger, Felix; Li, Jennifer S;

    2013-01-01

    BACKGROUND: Infants with cyanotic congenital heart disease palliated with placement of a systemic-to-pulmonary-artery shunt are at risk for shunt thrombosis and death. We investigated whether the addition of clopidogrel to conventional therapy reduces mortality from any cause and morbidity related......) or placebo (439 infants), in addition to conventional therapy (including aspirin in 87.9% of infants). The primary efficacy end point was a composite of death or heart transplantation, shunt thrombosis, or performance of a cardiac procedure due to an event considered to be thrombotic in nature before...

  11. Diagnosis and quantitation of left to right shunts using radioisotopes

    After intravenous injection of sup(99m)TcO4 into the femoral vein the count-rate vs. time curve of a lung field is recorded and analysed (Ohio Nuclear Camera ON 110, pdp 11 computer GAMMA 11, hp 5407 computer). Using a modified gamma function area-ratio technique, the size of the left to right shunts is calculated and compared with cardiac catheter results (128 patients). The localisation of the left to right shunt (ASD or VSD) is possible, if the shunt size rises over 30%. The method may be an alternative to oximetry and conventional dilution techniques. (orig.)

  12. Leakage Inductance Calculation for Planar Transformers with a Magnetic Shunt

    Zhang, Jun; Ouyang, Ziwei; Duffy, Maeve C.;

    2014-01-01

    The magnetic shunt is generally inserted in a planar transformer to increase the leakage inductance which can be utilized as the series inductor in resonant circuits such as the LLC resonant converter. This paper presents a calculation methodology for the leakage inductance of the transformer with...... a magnetic shunt by means of the stored magnetic energy in the primary and secondary sides of the transformer using the magnetomotive force (MMF) variation method, as well as the stored energy in the shunt based on the reluctance model. The detailed calculation method is described. Both the FEA...

  13. Gastric varices with spontaneous gastrorenal shunt: treated by retrograde gastrorenal shunt balloon occlusion combined with percutaneous transhepatic gastric varices embolization

    Objective: To evaluate the efficacy and the safety of retrograde gastrorenal shunt balloon occlusion combined with percutaneous transhepatic gastric varices embolization to treat the gastric varices with spontaneous gastrorenal shunt. Methods: From Nov. 2006 to Jun. 2010, retrograde gastrorenal shunt balloon occlusion combined with percutaneous transhepatic gastric varices embolization was performed on 8 patients who had gastric varices with spontaneous gastrorenal shunt. All the patients were men and the age ranged from 40 to 61 years. The balloon catheter was inserted into the spontaneous gastrorenal shunt through the right femoral vein, then percutaneous transhepatic splenic vein venography was performed to identify the number and morphology of gastric varices. After that gastric varices embolization was performed while the balloon catheter was dilated, which was withdrawn one day after the procedure. Results: Technical success of interventional treatment was achieved in all 8 cases with no significant complications. The increase of average portal venous pressure was 5.5 cm H2O (1 cm H2O=0.098 kPa, preoperative 35.0 to 41.0 cm H2O, postoperative 39.0 to 45.5 cm H2O). After follow up of 1 to 46 months, no recurrence haemorrhage occurred. Conclusion: Retrograde gastrorenal shunt balloon occlusion combined with percutaneous transhepatic gastric varices embolization can be safely performed and could be one of the effective choices for patients who had gastric varices with spontaneous gastrorenal shunt, which is not suitable to treat by the endoscopic sclerotherapy. (authors)

  14. Pollutants removal in subsurface infiltration systems by shunt distributing wastewater with/without intermittent aeration under different shunt ratios.

    Pan, Jing; Yuan, Fang; Zhang, Yang; Huang, Linli; Yu, Long; Zheng, Fanping; Cheng, Fan; Zhang, Jiadi

    2016-10-01

    Matrix dissolved oxygen (DO), removal of COD, TP and nitrogen in subsurface infiltration systems (SISs), named SIS A (without intermittent aeration and shunt distributing wastewater), SIS B (with shunt distributing wastewater) and SIS C (with intermittent aeration and shunt distributing wastewater) were investigated. Aerobic conditions were developed in 50cm depth and anoxic or anaerobic conditions were not changed in 80 and 110cm depth by intermittent aeration. Under appropriate shunt ratios, shunt distributing wastewater improved denitrification and had little influence on COD, TP and NH3-N removal. Under the optimal shunt ratio of 1:2 for SIS C, high average removal rates of COD (90.06%), TP (93.17%), NH3-N (88.20%) and TN (85.79%) were obtained, which were higher than those in SIS A (COD: 82.56%, TP: 92.76%, NH3-N: 71.08%, TN: 49.24%) and SIS B (COD: 81.12%, TP: 92.58%, NH3-N: 69.14%, TN: 58.73%) under the optimal shunt ratio of 1:3. PMID:27347804

  15. Effects of acute normovolemic hemodilution on intrapulmonary shunting and oxygenation during one-lung ventilation in dogs%急性等容血液稀释对犬单肺通气期间肺分流与氧合的影响

    马宁; 李树人; 槐庆元

    2001-01-01

    目的观察犬单肺通气期间,不同程度急性等容血液稀释对肺分流和氧供、氧耗等的影响.方法 12只健康杂种犬,基础麻醉后插入双腔气管导管,股动、静脉置管.稳定30分钟(HD0)后,以血定安等速置换全血,分别达到轻度(HDl)、中度(HD2)、重度(HD3)和极重度(HD4)血液稀释四个阶段.每阶段均分为双肺通气(TLV)和单肺通气(OLV),分别于各阶段TLV、OLVl5分钟后测量分流(Qs/Qt)及氧供(DO2)、氧耗(VO2)等各指标变化.结果随着HD程度的加深,平均动脉压、心输出量、肺血管阻力(PVR)、平均肺动脉压(MPAP)、氧分压、DO2等趋于降低,氧摄取率(ERO2)、血乳酸、Qs/Qt趋于增加,到HD3、HD4时已出现DO2-VO2依赖性降低及无氧酵解征象.与TLV时相比,OLV期间HD0、HD1及HD2组PVR、MPAP增高明显(P<0.01),而HD3、HD4组变化不大(P>0.05);OLV时QS/Qt增加更为明显,HD2、HD3及HD4组分别较基值增加74%、164%及177%(P<0.01).结论缺氧、ANHD均为影响Qs/Qt与氧合的重要因素,OLV时ANHD应以不低于中度为准.%Objective To evaluate the effects of different degrees of acute normovolemic hemodilution (ANH) on intrapulmonary shunting, oxygen delivery and consumption during one-lung ventilation(OLV) in dogs. Methods Twelve healthy mongrel dogs weighing 18-22 kg were anesthetized with Ⅳ pentobarbital sodium 20mg.kg-1, scopolamine 0.3 mg and pancuronium 0.2 mg. kg-1 and intubated with a left-sided Carlen' s tube. Correct positioning of the tube was verified by auscultation and by visual inspection after thoracotomy at the end of the experiment. The dogs were mechanically ventilated with 100% oxygen. PET CO2 was maintained between 4.67-6.00 kPa. ECG and rectal temperature were continuously monitored. An intravenous line was established for infusion of Lacted Ringer solution. SwanGanz catheter was inserted via femoral vein on one side for sampling of mixed venous blood and measurement of cardiac output (CO) by

  16. A case of breast cancer involving a ventriculoperitoneal shunt.

    Kamei, Mirei; Kikuchi, Nobuyuki; Ichimura, Homare; Chujo, Masao; Takahashi, Yoshiaki; Sugio, Kenji

    2016-12-01

    An 84-year-old woman was examined for an enlargement of an induration in the left breast. A ventriculoperitoneal shunt had been placed for postoperative normal pressure hydrocephalus of a cerebral hemorrhage, and it had penetrated the mass according to the computed tomography findings. Breast cancer was diagnosed after a close examination; however, close observation was selected because her family rejected treatment. She developed somnolence 7 months after the initial examination, and ventricular dilatation and expansion of the low-density region around the ventricle were noted on computed tomography, suggesting that the enlarged tumor had excluded the shunt and caused obstruction. The growth of breast carcinoma involving a shunt tube can be the cause of obstruction of a ventriculoperitoneal shunt. Our findings suggest that a breast lesion should be evaluated at both pre- and postoperation. PMID:26943684

  17. Ventriculoperitoneal Shunt Infection Caused by Actinomyces neuii subsp. neuii▿

    Watkins, Richard R.; Anthony, Kathy; Schroder, Suzanne; Hall, Gerri S.

    2008-01-01

    Actinomyces neuii subsp. neuii is a rare isolate in clinical specimens. The organism was previously designated CDC coryneform group 1 and was renamed in 1994. A case of a ventriculoperitoneal shunt infection caused by this organism is described.

  18. [A simple peritoneovenous shunt in the treatment of chronic ascites].

    Pafko, P; Hladík, P

    2001-02-01

    The authors describe their own initial experience with a peritoneo-venous shunt in otherwise incurable ascites. It is a simple procedure which is more satisfactory than the formerly used technique of implantation of Le Veen's system. PMID:12881921

  19. [Sapheno-peritoneal shunt for the treatment of ascites].

    Nagy, Z; Gyurkovics, E; Kaliszky, P; Kupcsulik, P

    2001-08-01

    For the surgical treatment of drug resistant ascites caused by hepatic cirrhosis usually different types of valvular plastic tubes are used, implanted as peritoneo-venous shunts. These shunts drain the ascites into the jugular vein. In the 1st Surgical Department of the Semmelweis University Budapest we have performed 267 peritoneo-venous shunt operations. We introduced a new method using an autolog venous graft with a peritoneo-venous anastomosis, that drains the ascites into the saphenous, then femoral vein. So far we performed 5 such interventions. The early results suggest that sapheno-peritoneal shunt can be successfully used for treatment of ascites. With this operation complications of plastic grafts are avoidable. PMID:11550492

  20. Shunt loudspeaker techniques for use as liners for engine nacelles

    Lissek, Hervé

    2009-01-01

    In this paper, the liner concept is an electroacoustic transducer which acoustic impedance can be changed by electrical means, be it passive or active. Among the different ways to obtain variable acoustic properties on an electroacoustic transducer's voicing face is the shunting of the transducer's electrical input. With such shunt devices, the acoustic impedance that the transducer's membrane presents to the acoustic field takes account of an acoustic equivalent of the electrical load that c...

  1. Longitudinal Shunt Slot Excitation by Wiggly Ridge Substrate Integrated Waveguide

    Mehdi Salemi; Mehdi Moradian; Reza Safian

    2014-01-01

    Application of a substrate integrated waveguide with wiggly ridge shape is presented for excitation longitudinal shunt slot antenna. Two main design equations for design substrate integrated waveguide structure and get parameters of structures, for longitudinal shunt slot excitation by shape wiggly ridge in substrate integrated waveguide are modified. Proposed method is used by applied the crinkle shape to ridge for ridge substrate integrated waveguide structure. This shape wiggly ridge just...

  2. Hearing Loss in Patients with Shunt-Treated Hydrocephalus.

    Panova, Margarita V; Geneva, Ina E; Madjarova, Kalina I; Bosheva, Miroslava N

    2015-01-01

    Hearing loss is a common manifestation of the long-term complications in patients with shunt treated hydrocephalus along with motor development disturbance, cognitive and visual impairment, epilepsy and endocrine disorders. The aim of the present study was to investigate the alterations of hearing in patients with shunt treated hydrocephalus of non-tumor etiology and at least one year after implantation of ventriculo-peritoneal shunt, as well as their impact on the quality of life of patients. The study included 70 patients (age range 1.25 years - 21.25 years) with shunted non-tumor hydrocephalus and at least one year after placement of the shunt system. Hearing alterations were proved by measuring the brainstem auditory evoked potentials (BAEP) for children up to 5 years of age and children with mental retardation; audiograms was used for children older than 5 years with normal neuro-psychological development (NPD). Of the 70 studied patients 17 (24%) had hearing loss (10 bilateral and 7-unilateral) and all of them had sensorineural hearing loss, which is associated with low weight at birth, posthemorrhagic hydrocephalus and brainstem symptoms at the time of diagnosis of hydrocephalus. Hearing pathology was found more often in shunt-treated patients with NPD retardation, poor functional status and low quality of life. Children with shunt-treated hydrocephalus have hearing loss of sensorineural type. Children with brain stem symptomatology at diagnosing hydrocephalus and children with post-hemorrhagic hydrocephalus show higher risk of hearing loss. Children with shunted hydrocephalus and hearing loss show lower NPD, lower quality of life and lower functional status. PMID:27180348

  3. Decompression of superior vena cava during bidirectional Glenn shunt

    Kulkarni Venugopal; Mudunuri Ravikiran; Mulavisala Krishnaprasad; Byalal R

    2009-01-01

    Patients undergoing bi-directional Glenn shunt for various congenital anomalies of the heart will have their superior vena cava (SVC) clamped during the procedure. The duration of the procedure is variable, ranging from five to 30 minutes. This can affect the cerebral perfusion due to raised venous pressure [Cerebral blood flow = Mean arterial pressure − (Intracranial pressure + Central venous pressure)]. Shunting away the SVC blood is a well known technique to counter this probl...

  4. Cerebral Venous Thrombosis after Ventriculoperitoneal Shunting: A Case Report

    Matsubara, Teppei; AYUZAWA, Satoshi; AOKI, Tsukasa; Ikeda, Go; SHIIGAI, Masanari; Matsumura, Akira

    2013-01-01

    Ventriculoperitoneal shunting (VPS) is a simple procedure, but there are several potential complications. We describe the first reported case of cerebral venous thrombosis (CVT) after VPS. A 69-year-old man suffering from normal pressure hydrocephalus underwent left VPS. Two months later he developed CVT and cerebral venous hemorrhage in the left frontal lobe. Computed tomography (CT) and magnetic resonance imaging (MRI) revealed the thrombus formation just adjacent to the shunt tube. One pos...

  5. Baclofen overdose from possible intrinsic malfunction of SynchroMed II pump.

    Davanzo, Justin R; Rizk, Elias

    2015-08-01

    This is a case report illustrating an overdose of baclofen in a 10-year-old boy due to a likely malfunction of a SynchroMed II pump. This ultimately necessitated a pump replacement. One-year follow-up showed no further incidents of baclofen overdose, with multiple pump refills. PMID:25978532

  6. DEVELOPMENT OF AN EXPERT SYSTEM FOR DIAGNOSIS MALFUNCTIONS OF ENGINES OF DIESEL POWER STATIONS

    Laptev V. N.

    2015-12-01

    Full Text Available The article considers development of expert system based on semantic networks for diagnosis malfunctions of the diesel power stations engines. The method allows developing expert systems via objectoriented programming language. The expert system allows to identify the problem without involving additional staff: at the start and overheats of the engine, when there is low power, with decreasing pressure etc

  7. Validation of a novel method for detecting and stabilizing malfunctioning areas in fuel cell stacks

    Müller, Martin; Hirschfeld, Julian; Lambertz, Rita; Schulze Lohoff, Andreas; Lustfeld, Hans; Pfeifer, Heinz; Reißel, Martin

    2014-12-01

    In this paper a setup for detecting malfunctioning areas of MEAs in fuel cell stacks is described. Malfunctioning areas generate electric cross currents inside bipolar plates. To exploit this we suggest bipolar plates consisting not of two but of three layers. The third one is a highly conducting layer and segmented such that the cross currents move along the segments to the surface of the stack where they can be measured by an inductive sensor. With this information a realistic model can be used to detect the malfunctioning area. Furthermore the third layer will prevent any current inhomogeneity of a malfunctioning cell to spread to neighbouring cells in the stack. In this work the results of measurements in a realistic cell setup will be compared with the results obtained in simulation studies with the same configuration. The basis for the comparison is the reliable characterisation of the electrical properties of the cell components and the implication of these results into the simulation model. The experimental studies will also show the limits in the maximum number of segments, which can be used for a reliable detection of cross currents.

  8. Correction of malfunctioning peritoneal dialysis catheter with guidewire and stiffener under fluoroscopic guidance

    To determine the efficacy of correction of a malfunctioning peritoneal dialysis catheter with guidewire and stiffener under fluoroscopic guidance. Between November 1994 and March 1997, we performed 15 manipulations in 12 patients in whom a dual-cuff, straight Tenckhoff peritoneal dialysis catheter had been implanted due to chronic renal failure. The causes of catheter malfunctioning were inadequate drainage of the dialysate(n=14) and painful dialysis(n=1). Under fluoroscopic guidance, adhesiolysis and repositioning of the malfunctioning catheter were performed with an Amplatz Super Stiff guidewire and the stiffener from a biliary drainage catheter. The results of procedures were categorized as either immediate or durable success, this latter being defined as adequate catheter function for at least one month after the procedure. Immediate success was achieved in 14 of 15 procedures (93%), and durable success in 7 of 15(47%). The mean duration of catheter function was 157 (range, 30 to 578) days. After manipulation, abdominal pain developed in eight patients and peritonitis in two, but with conservative treatment, these symptoms improved. The correction of a malfunctioning peritoneal dialysis catheter with guidewire and stiffener under fluoroscopic guidance is an effective means of restoring catheter function and may be an effective alternative to surgical reimplantation of the catheter, or hemodialysis

  9. 40 CFR 65.6 - Startup, shutdown, and malfunction plan and procedures.

    2010-07-01

    ... sources referenced from 40 CFR part 63, subpart F, by the compliance date specified in that subpart. The... 40 Protection of Environment 15 2010-07-01 2010-07-01 false Startup, shutdown, and malfunction... (CONTINUED) AIR PROGRAMS (CONTINUED) CONSOLIDATED FEDERAL AIR RULE General Provisions § 65.6...

  10. 40 CFR 62.14645 - What happens during periods of startup, shutdown, and malfunction?

    2010-07-01

    ... 40 Protection of Environment 8 2010-07-01 2010-07-01 false What happens during periods of startup... Limits § 62.14645 What happens during periods of startup, shutdown, and malfunction? (a) The emission limitations and operating limits apply at all times except during periods of CISWI unit startup, shutdown,...

  11. Malfunctioned and Fractured Penile Prosthesis Caused by Cross Placement: Case Report

    Nihat Karakoyunlu

    2015-05-01

    Full Text Available Penile prosthesis is a functional option for patients who have erectile dysfunction after failed medical and intracavernosal treatments. Malleable penile prosthesis is a good alternative. Penile prosthesis implantation is a surgical process. Seldomly complications occur. In this study we presented a 61 y old man who has malfunctioned and broken penile prosthesis due to cross implantation.

  12. Malfunctioned and Fractured Penile Prosthesis Caused by Cross Placement: Case Report

    Nihat Karakoyunlu; Sercan Sarı; Harun Ozdemir; Hikmet Topaloglu; Ugur Ozok; Levent Sagnak; Hamit Ersoy

    2015-01-01

    Penile prosthesis is a functional option for patients who have erectile dysfunction after failed medical and intracavernosal treatments. Malleable penile prosthesis is a good alternative. Penile prosthesis implantation is a surgical process. Seldomly complications occur. In this study we presented a 61 y old man who has malfunctioned and broken penile prosthesis due to cross implantation.

  13. Analytical study of ventilation-system behavior using TVENT1 under simulated blower malfunctions

    A large, complex ventilation system at the Los Alamos National Laboratory's Plutonium Processing Facility was modeled and analyzed using a computer code called TVENT1. Useful information was obtained about the system's operating characteristics when subjected to potential blower malfunctions. This report provides an excellent example for a potential user of TVENT1 for application to an actual system

  14. 40 CFR 62.15165 - What happens to the emission limits during periods of startup, shutdown, and malfunction?

    2010-07-01

    ... subpart A of 40 CFR part 60 apply. Continuous Emission Monitoring ... during periods of startup, shutdown, and malfunction? 62.15165 Section 62.15165 Protection of Environment... emission limits during periods of startup, shutdown, and malfunction? (a) The emission limits of...

  15. 40 CFR 60.1710 - What happens to the emission limits during periods of startup, shutdown, and malfunction?

    2010-07-01

    ... during periods of startup, shutdown, and malfunction? 60.1710 Section 60.1710 Protection of Environment... during periods of startup, shutdown, and malfunction? (a) The emission limits of this subpart apply at all times except during periods of municipal waste combustion unit startup, shutdown, or...

  16. 40 CFR 60.1695 - What happens to the operating requirements during periods of startup, shutdown, and malfunction?

    2010-07-01

    ... requirements during periods of startup, shutdown, and malfunction? 60.1695 Section 60.1695 Protection of... Requirements § 60.1695 What happens to the operating requirements during periods of startup, shutdown, and... municipal waste combustion unit startup, shutdown, or malfunction. (b) Each startup, shutdown,...

  17. 40 CFR 62.15150 - What happens to the operating requirements during periods of startup, shutdown, and malfunction?

    2010-07-01

    ... requirements during periods of startup, shutdown, and malfunction? 62.15150 Section 62.15150 Protection of... § 62.15150 What happens to the operating requirements during periods of startup, shutdown, and... municipal waste combustion unit startup, shutdown, or malfunction. (b) Each startup, shutdown,...

  18. 40 CFR 60.1205 - What happens to the operating requirements during periods of startup, shutdown, and malfunction?

    2010-07-01

    ... requirements during periods of startup, shutdown, and malfunction? 60.1205 Section 60.1205 Protection of... requirements during periods of startup, shutdown, and malfunction? (a) The operating requirements of this subpart apply at all times except during periods of municipal waste combustion unit startup, shutdown,...

  19. Minimally Invasive-Endoscopic Intraventricular Neurosurgery

    Full Text Available ... ultimately result in difficulty with vision, strokes and death. I'm sure probably some people are watching ... an acute shunt malfunction can manifest. And sudden death has been described in endoscopic third ventriculostomy reclosure. ...

  20. First Report of Ventriculoperitoneal Shunt Infection due to Cyberlindnera fabianii

    Jonathan Baghdadi

    2015-01-01

    Full Text Available Fungal infections in the central nervous system (CNS are associated with significant morbidity and death. Transient fungemia in immunocompetent patients without any other risk factors for fungemia has been suggested as a possible mechanism that may lead to serious fungal ventriculoperitoneal (VP shunt infections, but evidence is lacking. The clinical spectrum, diagnosis, and optimal therapy of Cyberlindnera fabianii infections remain to be determined. We describe the first case of CNS infection due to C. fabianii that occurred in an immunocompetent adult with a VP shunt. Spontaneous translocation with yeast that is not part of the normal gastrointestinal flora in the setting of ingestion of multiple servings of a fermentation product was the likely source from which Cyberlindnera fabianii gained entrance into the VP shunt system, causing meningitis in this patient. The authors conclude that, in view of the high morbidity associated with yeast infection of the CNS, long-term antifungal therapy should be strongly considered in cases where the VP shunt cannot be completely removed. Transient fungemia may lead to invasive disease in an immunocompetent host with VP shunt, even in the absence of any other risk factors for fungemia and even after remote placement of the VP shunt.

  1. Shunt switched resistor regulator with diode snubber

    Ekstrand, J.

    1989-03-21

    This patent describes a shunt switched resistor regulator power supply for supplying a variable amount of power to a load comprising: a rectifier means for accepting AC input voltage and converting it to DC output voltage at a positive and a negative terminal; first, second, third, and fourth nodes wherein the first and the fourth nodes are coupled to the positive and negative terminals, respectively; a current limiting resistor coupled between the first and second nodes; a capacitor coupled between the second and fourth nodes; a resistor having parasitic inductance coupled between the second and third nodes; a switch coupled between the third and fourth nodes; and a diode having its anode coupled to the third node and having its cathode coupled to the second node; means coupled to the load terminals for sensing the power being delivered to the load and for controlling the switch to have a duty cycle which results in the desired load current flowing through and a desired voltage appearing across the load in accordance with control input signals received at a control input.

  2. How automation malfunctions influence operator performance. study plan for the HCA-2000 experiment

    Skjerve, Ann Britt Miberg; Andresen, Gisle; Saarni, Ray; Skraaning, Gyrd Jr.

    2001-03-15

    This report presents the Study Plan for the Human-Centred Automation Programme's experiment in year 2000. The purpose of the experiment is to examine how two types of automation malfunctions influence operator performance when operators work from two different types of interfaces for presenting information about the activities of the automatic system. The experiment is performed using the Nokia Research Simulator of HAMMLAB. Licensed operators act as experimental participants. They participate in crews consisting of two operators. The experimental design applied is a 2x2(x3) within-subject design. The independent variable of automation malfunction type has two levels. These are defined with reference to slips-mistakes distinction that has been used to classify human errors. A control-system component malfunction (CSCM) constitutes an automation slip, i.e. a failure in execution. A situation-dependent strategy malfunction (SDSM) constitutes an automation mistake, i.e. a failure in planning. The independent variable of automation-information presentation (AIP) type also has two levels. These are defined with reference to the degree in which the interfaces depict information about the activity of the automatic system, and relate to the idea of operators' mental isolation from automation. The conventional AIP interface provides limited information about the activity of the automatic system. The experimental AIP interface provides information about the activity of the main automatic devices and offers verbal semantically meaningful feedback. The overall experimental hypotheses state that operators will correctly handle CSCM faster than SDSM, and that automation malfunctions will be dealt with correctly faster from the experimental rather than a conventional AIP interface. They also state that the influence of the automation-malfunction type in general will be stronger than the influence of the AIP interface type. The experiment includes an additional set of

  3. Transjugular intrahepatic portosystemic shunt for the treatment of portal vein thrombus:its current status

    The prevalence of portal vein thrombosis in the general population is about 1.1%, while it is about 10%-25% in the cirrhotic patients. The severe clinical complication in patients with acute portal vein thrombosis is ischemic intestinal infarction when the thrombus extends to the mesenteric venous arch. The complications include bleeding due to gastroesophageal varices, ascites and deterioration of live function in the patients with chronic portal vein thrombosis. The recently-published Practice Guidelines indicate that the treatment of portal vein thrombosis includes anticoagulation,thrombolysis, transjugular intrahepatic portosystemic shunt (TIPS) and surgical thrombectomy. TIPS has some advantages in treating portal vein thrombus. It can directly and effectively re-canalize the occluded portal vein. Moreover, it can accelerate portal flow and prevent recurrent thrombosis after the shunt is well-established. The disadvantages of TIPS include technical difficulties and potential complications. However, percutaneous transhepatic, transsplenic and transmesenteric approaches well facilitate the TIPS procedure. Additionally, preoperative evaluation of portal vein anatomy can provide a safe and effective choice in treating patients with portal cavernoua caver who are going to receive TIPS. Nevertheless, in the absence of relevant prospective studies, the application of TIPS for the management of portal vein thrombosis is still limited. (authors)

  4. Laparoscopy for ventriculoperitoneal shunt implantation and revision surgery

    Fernando; Campos; Gomes; Pinto; Matheus; Fernandes; de; Oliveira

    2014-01-01

    Ventriculoperitoneal shunting(VPS) is a widely accepted technique for the treatment of hydrocephalus. The probability of shunt dysfunction is pretty high throughout life. Laparoscopy has become a valuable tool to perform VPS and treat abdominal complications. An electronic literature search was performed to reveal the published data relating laparoscopy and ventriculoperitoneal shunt in Medline, Embase, Scielo and Lilacs databases. The keywords employed were “laparoscopy” OR “laparoscopic surgery” AND “ventriculoperitoneal shunt” OR “shunt” AND “surgery” OR “implantation” OR “revision” OR “complication”. No high quality trials were developed comparing conventional laparotomic incision vs laparoscopic approach. Both approaches have evolved and currently there are less invasive options for laparotomy, like periumbilical small incisions; and for laparoscopy, like smaller and less incisions. Operating room time, blood loss and hospital stay may be potentially smaller in laparoscopic surgery and complications are probably the same as laparotomy. In revision surgery for abdominal complications after VPS,visualization of whole abdominal cavity is fundamental to address properly the problem and laparoscopic approach is valuable once it is safe, fast and much less invasive than laparotomy. Ventriculoperitoneal shunting is a widely accepted technique for the treatment of hydrocephalus. Laparoscopy assisted shunt surgery in selected cases might be a less invasive and more effective option for intrabdominal manipulation. The laparoscopic approach allows a better catheter positioning, lysis of fibrotic bundles and peritoneal inspection as well, without any additional complication.

  5. Multiple Chaotic Central Pattern Generators with Learning for Legged Locomotion and Malfunction Compensation

    Ren, Guanjiao; Chen, Weihai; Dasgupta, Sakyasingha;

    2015-01-01

    on a simulated annealing algorithm. In a normal situation, the CPGs synchronize and their dynamics are identical. With leg malfunction or disability, the CPGs lose synchronization leading to independent dynamics. In this case, the learning mechanism is applied to automatically adjust the remaining legs...... chaotic CPG controller has difficulties dealing with leg malfunction. Specifically, in the scenarios presented here, its movement permanently deviates from the desired trajectory. To address this problem, we extend the single chaotic CPG to multiple CPGs with learning. The learning mechanism is based...... in a physical simulation of a quadruped as well as a hexapod robot and finally in a real six-legged walking machine called AMOSII. The experimental results presented here reveal that using multiple CPGs with learning is an effective approach for adaptive locomotion generation where, for instance, different body...

  6. Comparison of Common Methods in Dynamic Response Predictions of Rotor Systems with Malfunctions

    Hongliang Yao; Qian Zhao; Qi Xu; Bangchun Wen

    2014-01-01

    The efficiency and accuracy of common time and frequency domain methods that are used to simulate the response of a rotor system with malfunctions are compared and analyzed. The Newmark method and the incremental harmonic balance method are selected as typical representatives of time and frequency domain methods, respectively. To improve the simulation efficiency, the fixed interface component mode synthesis approach is combined with the Newmark method and the receptance approach is combined ...

  7. [Massive endocardial thrombosis in a patient with a peritoneo-jugular shunt for refractory ascites: the therapeutic success of tissue plasminogen activator and defibrotide].

    Sacchetti, C; Pederzoli, S; Tamborrino, E; Grandi, M

    1994-01-01

    The authors report a case of a patient with a refractory ascites due to extrahepatic portal thrombosis in course of idiopathic thrombocythemia. A peritoneovenous shunt was applied and as a late complication a massive thrombosis of the intracardiac portion of the duct developed. Thrombolysis was obtained with tissue plasminogen activator at doses usually administered for acute myocardial infarction. Prophylaxis of recurrence was pursued with pictomide and defibrotide. PMID:8079040

  8. An Experimental Study of Emission and Combustion Characteristics of Marine Diesel Engine with Fuel Injector Malfunctions

    Kowalski Jerzy

    2016-01-01

    Full Text Available The presented paper shows the results of the laboratory study on the relation between chosen malfunctions of a fuel injector and composition of exhaust gas from the marine engine. The object of research is a marine 3-cylinder, four-stroke, direct injection diesel engine with an intercooler system. The engine was loaded with a generator and supercharged. The generator was electrically connected to the water resistance. The engine operated with a load between 50 kW and 250 kW at a constant speed. The engine load and speed, parameters of the turbocharger, systems of cooling, fuelling, lubricating and air exchange, were measured. Fuel injection and combustion pressures in all cylinders of the engine were also recorded. Exhaust gas composition was recorded by using a electrochemical gas analyzer. Air pressure, temperature and humidity were also recorded. Emission characteristics of the engine were calculated according to ISO 8178 standard regulations. During the study the engine operated at the technical condition recognized as „working properly” and with simulated fuel injector malfunctions. Simulation of malfunctions consisted in the increasing and decreasing of fuel injector static opening pressure, decalibration of fuel injector holes and clogging 2 neighboring of 9 fuel injector holes on one of 3 engine cylinders.

  9. Development of expert system on personal computer for diagnosis of nuclear reactor malfunctions

    An expert system on a personal computer has been developed for diagnosis of malfunction of the fast experimental reactor 'JOYO'. Prolog-KABA is used as the language. The system diagnoses the event which causes scram or set-back of the control rod after an alarm at steady state operation. The knowledge base (KB) consists of several sub-KBs and a meta-KB. Using the forward chaining, the meta-KB decides which sub-KB should be accessed. The cause of the malfunction is identified in the sub-KB using the backward chaining. The terms expressing the characteristics of the events are involved in the production rules as attributes in order to use the Prolog function of pattern matching and back-tracking for efficient inference. The total number of the rules in the system is about 400. The experiments using the plant simulator of 'JOYO' have shown that malfunctions are successfully identified by the diagnosis system. It takes about 10s for each diagnosis using the 16-bits personal computer, PC-9801 VM. (author)

  10. Association of distinct intracranial pial and dural arteriovenous shunts

    Vilela, P. [Neuroradiology Dept., Garcia de Orta Hospital (Portugal); Brugge, K. ter; Willinsky, R. [Toronto Western Hospital, Div. of Neuroradiology, Toronto, ON (Canada)

    2001-09-01

    Intracranial pial and dural arteriovenous shunts may exist at different sites in the same patient. The etiology, natural history and treatment of these associated conditions have not been completely determined. We reviewed the records of 765 cases of pial arteriovenous malformation and 137 dural arteriovenous fistulae and malformations. We selected eight patients with both pial and dural arteriovenous shunts, separate anatomically, with distinct feeding arteries and draining veins, representing 1 % of pial and 17 % of dural shunts. Presentation was related to the dural lesion in 5 cases (62.5 %) and to the pial malformation in three (37.5 %). Treatment of these lesions should be considered separately based on their angioarchitecture and natural history. (orig.)

  11. Effects of an interatrial shunt on rest and exercise hemodynamics

    Kaye, David; Shah, Sanjiv J; Borlaug, Barry A; Gustafsson, Finn; Komtebedde, Jan; Kubo, Spencer; Magnin, Chris; Maurer, Mathew S; Feldman, Ted; Burkhoff, Daniel

    2014-01-01

    BACKGROUND: A treatment based on an interatrial shunt device has been proposed for counteracting elevated pulmonary capillary wedge pressure (PCWP) in patients with heart failure and mildly reduced or preserved ejection fraction (HFpEF). We tested the theoretical hemodynamic effects of this...... approach with the use of a previously validated cardiovascular simulation. METHODS AND RESULTS: Rest and exercise hemodynamics data from 2 previous independent studies of patients with HFpEF were simulated. The theoretical effects of a shunt between the right and left atria (diameter up to 12 mm) were...... determined. The interatrial shunt lowered PCWP by ~3 mm Hg under simulated resting conditions (from 10 to 7 mm Hg) and by ~11 mm Hg under simulated peak exercise conditions (from 28 to 17 mm Hg). Left ventricular cardiac output decreased ~0.5 L/min at rest and ~1.3 L/min at peak exercise, with corresponding...

  12. Computer analysis of radiocardiograms of patients with intracardiac shunts

    In 112 patients catheterized for congenital heart disease, radiocardiographic data have been collected by right atrial injection of sup(113m)In. Four scintillation detectors were used to monitor the activity changes in the heart, lungs and head. The heart measurements were done with both frontal and left lateral detectors, the latter being constructed for better collimation and efficiency. The CAMAC system and PDP-9 computer served for data collection, storage analysis, and display. Data were collected at 10 or 20 points per second and the pulsatile output of heart curves recorded. Since radiocardiograms in patients with shunts are complex, a computer program (PULSE) incorporating a pulsatile heart model was written for radiocardiogram simulation and analysis. The model consists of a series of compartments pulsating alternately. From each compartment a certain fraction of indicator is ejected into the next compartment and added to the indicator retained there. Each cardiac chamber is represented by one compartment, while pulmonary and systemic circulation are represented by a series of paired number of compartments. For shunt simulation a certain fraction can be ejected backward or forward along the series. In order to shorten the computation the model was fitted only to the end-diastolic and end-systolic states of the compartments. In left-to-right haemodynamically significant shunts the heart and lung curves show recirculation peaks. In right-to-left shunts the head curve detects the early arrival of indicator and shows a biphasic character. The addition of a computer for data acquisition and for pulsatile model simulation and analysis makes it possible to estimate shunt flows. Estimates correlate well with results of standard shunt measurements. (author)

  13. Endovascular occlusion of high-flow intracranial arteriovenous shunts: technical note

    van Rooij, Willem Jan; Sluzewski, Menno

    2007-01-01

    Endovascular closure of high-flow arteriovenous (AV) shunts in intracranial AV malformations or pial fistulas is technically challenging. In this paper, we illustrate two simple methods to occlude large high-flow AV shunts in a controlled manner.

  14. Endophthalmitis associated with Glaucoma Shunt Intraluminal Stent Exposure

    Kerr, Nathan M; Ruddle, Jonathan B; Ang, Ghee Soon

    2016-01-01

    ABSTRACT Endophthalmitis post glaucoma drainage implant (GDI) surgery is rare, often associated with tube or plate exposure. We report a case of endophthalmitis following glaucoma shunt intraluminal stent exposure in a patient who underwent Baerveldt glaucoma implant surgery. Endophthalmitis following manipulation of intraluminal stents is a rare complication of GDIs but potentially vision threatening condition that needs to be carefully screened for and treated immediately. How to cite this article: Kwon HJ, Kerr NM, Ruddle JB, Ang GS. Endophthalmitis associated with Glaucoma Shunt Intraluminal Stent Exposure. J Curr Glaucoma Pract 2016;10(1):36-37.

  15. Unusual manifestations of infection following shunt: An interesting case summary

    Raj Kumar

    2007-01-01

    Full Text Available One 3 years male child was operated for a large vermian pilocytic astrocytoma. He developed fever and features of raised intracranial pressure after 2 weeks to require external ventricular drainage and ventriculoperitoneal shunt subsequently. The cause of fever could not be established even after thorough repeated investigations in this child and he did not respond to changing antibiotics during next 2 weeks. He responded dramatically to empirical antituberculous chemotherapy, which was started on the basis of history of contact with tuberculosis. The role of uncommon shunt infection is discurred to explain the clinical scenario in this case.

  16. Treatment of Portosystemic Shunt Myelopathy with a Stent Graft Deployed through a Transjugular Intrahepatic Route

    Jain, Deepak, E-mail: deepakjain02@yahoo.com; Arora, Ankur, E-mail: aroradrankur@yahoo.com [Institute of Liver and Biliary Sciences, Department of Radiology (India); Deka, Pranjal, E-mail: drpranjaldeka@gmail.com [Institute of Liver and Biliary Sciences, Department of Hepatopancreatobiliary Surgery (India); Mukund, Amar, E-mail: dramarmukund@gmail.com; Bhatnagar, Shorav, E-mail: drshorav@yahoo.com [Institute of Liver and Biliary Sciences, Department of Radiology (India); Jindal, Deepti, E-mail: deepijindal@rediffmail.com; Kumar, Niteen, E-mail: drniteenkumar@gmail.com; Pamecha, Viniyendra, E-mail: viniyendra@yahoo.co.uk [Institute of Liver and Biliary Sciences, Department of Hepatopancreatobiliary Surgery (India)

    2013-08-01

    A case of surgically created splenorenal shunt complicated with shunt myelopathy was successfully managed by placement of a stent graft within the splenic vein to close the portosystemic shunt and alleviate myelopathy. To our knowledge, this is the first report of a case of shunt myelopathy in a patient with noncirrhotic portal fibrosis without cirrhosis treated by a novel technique wherein a transjugular intrahepatic route was adopted to deploy the stent graft.

  17. Initial clinical experience with a new pulsed dye laser device in angioplasty of limb ischemia and shunt fistula obstructions

    Selective plaque ablation with laser radiation at 405-530 nm in vitro has been reported. The possibilities are investigated of a new pulsed dye laser device for in vivo recanalization of arteries in ischemic lower limbs and stenoses/occlusions of arterio-venous hemo-dialysis shunt fistulae. A specially designed 9F or 7F multifiber catheter was used for treatment of 10 patients with lower limb artery obliterations and 11 patients with malfunctioning hemodialysis access fistulae (HAF). The recanalization technical success was 5/5 in the iliac arteries (IA), 4/5 in the superficial femoral arteries (SFA), and 11/11 in the HAF. Early re-occlusions occurred in one SFA and IA, respectively, caused by very bad run-off. There was one clinically insignificant SFA perforation. Additional balloon angioplasty was considered necessary in 10/16 lesions. Mean ankle-arm index increased from 0.68 to 0.97. With two exceptions all HAF patients were re-integrated in the dialysis program. Pulsed dye laser angioplasty promises to be an effective and fast method for plaque ablation debulking. The first clinical experience confirms previous in vitro results. In particular laser recanalization may become the method of choice for treatment of rigid HAF obstructions and it seems to be superior to vascular surgery or balloon angioplasty alone. (author). 15 refs.; 2 figs

  18. Risk factors associated with hemodialysis central venous catheter malfunction; a retrospective analysis of a randomized controlled trial

    Ward, David R.; Moist, Louise M.; MacRae, Jennifer M; Scott-Douglas, Nairne; Zhang, Jianguo; Tonelli, Marcello; Lok, Charmaine E.; Soroka, Steven D; Hemmelgarn, Brenda R

    2014-01-01

    Background We previously reported a reduction in central venous catheter (CVC) malfunction when using once-weekly recombinant tissue-plasminogen activator (rt-PA) as a locking solution, compared with thrice-weekly heparin. Objectives To identify risk factors for CVC malfunction to inform a targeted strategy for rt-PA use. Design Retrospective analysis. Setting Canadian hemodialysis (HD) units. Patients Adults with newly placed tunnelled upper venous system CVCs randomized to a locking solutio...

  19. Locally Resonant Gaps of Phononic Beams Induced by Periodic Arrays of Resonant Shunts

    CHEN Sheng-Bing; WEN Ji-Hong; WANG Gang; HAN Xiao-Yun; WEN Xi-Sen

    2011-01-01

    @@ Periodic arrays of shunted piezoelectric patches are employed to control the propagation of elastic waves in phononic beams.Each piezo-patch is connected to a single resistance-inductance-capacitance shunting circuit.Therefore,the resonances of the shunting circuits will produce locally resonant gaps in the phononic beam.However,the existence of locally resonant gaps induced by resonant shunts has not been clearly proved by experiment so far.In this work,the locally resonant gap in a piezo-shunted phononic beam is investigated theoretically and verified by experiment.The results prove that resonances of shunting circuits can produce locally resonant gaps in phononic beams.%Periodic arrays of shunted piezoelectric patches are employed to control the propagation of elastic waves in phononic beams. Each piezo-patch is connected to a single resistance-inductance-capacitance shunting circuit. Therefore, the resonances of the shunting circuits will produce locally resonant gaps in the phononic beam. However, the existence of locally resonant gaps induced by resonant shunts has not been clearly proved by experiment so far. In this work, the locally resonant gap in a piezo-shunted phononic beam is investigated theoretically and verified by experiment. The results prove that resonances of shunting circuits can produce locally resonant gaps in phononic beams.

  20. Shoulder tip pain: an under-reported complication of ventriculoperitoneal shunt.

    Lim, C

    2012-02-03

    Ventriculoperitoneal (VP) shunt insertion is the commonest form of treatment for hydrocephalus. Shoulder tip pain after VP shunt insertion is unusual and has only recently been reported. We present a case of excruciating shoulder tip pain due to diaphragmatic irritation after VP shunt insertion.

  1. NH4+ triggers the release of astrocytic lactate via mitochondrial pyruvate shunting

    Lerchundi, Rodrigo; Fernández-Moncada, Ignacio; Contreras-Baeza, Yasna; Sotelo-Hitschfeld, Tamara; Mächler, Philipp; Wyss, Matthias T.; Stobart, Jillian; Baeza-Lehnert, Felipe; Alegría, Karin; Weber, Bruno; Barros, L. Felipe

    2015-01-01

    Neural activity is accompanied by a transient mismatch between local glucose and oxygen metabolism, a phenomenon of physiological and pathophysiological importance termed aerobic glycolysis. Previous studies have proposed glutamate and K+ as the neuronal signals that trigger aerobic glycolysis in astrocytes. Here we used a panel of genetically encoded FRET sensors in vitro and in vivo to investigate the participation of NH4+, a by-product of catabolism that is also released by active neurons. Astrocytes in mixed cortical cultures responded to physiological levels of NH4+ with an acute rise in cytosolic lactate followed by lactate release into the extracellular space, as detected by a lactate-sniffer. An acute increase in astrocytic lactate was also observed in acute hippocampal slices exposed to NH4+ and in the somatosensory cortex of anesthetized mice in response to i.v. NH4+. Unexpectedly, NH4+ had no effect on astrocytic glucose consumption. Parallel measurements showed simultaneous cytosolic pyruvate accumulation and NADH depletion, suggesting the involvement of mitochondria. An inhibitor-stop technique confirmed a strong inhibition of mitochondrial pyruvate uptake that can be explained by mitochondrial matrix acidification. These results show that physiological NH4+ diverts the flux of pyruvate from mitochondria to lactate production and release. Considering that NH4+ is produced stoichiometrically with glutamate during excitatory neurotransmission, we propose that NH4+ behaves as an intercellular signal and that pyruvate shunting contributes to aerobic lactate production by astrocytes. PMID:26286989

  2. High-Flow Arterio-Hepatic Venous Shunt in Hepatocellular Carcinoma: Use of Multi-Electrode Radiofrequency for Shunt Obliteration

    Intra-tumoral arterio-hepatic venous shunting (AHVS) poses an impediment to transarterial chemoembolization of liver tumors. Not only does it present a potential hazard for systemic shunting and embolization, but also the altered flow dynamics may also result in poor delivery of drug/embolics to the target tumor bed. Current available techniques to overcome AVHS include arterial embolization (particles, coils, glue, etc.) or temporary venous occlusion using balloons. We hereby illustrate the use of radiofrequency ablation to obliterate a complex AHVS consisting of a varix-like venous aneurysm

  3. High-Flow Arterio-Hepatic Venous Shunt in Hepatocellular Carcinoma: Use of Multi-Electrode Radiofrequency for Shunt Obliteration

    Pua, Uei, E-mail: druei@yahoo.com [Tan Tock Seng Hospital, Department of Diagnostic Radiology (Singapore)

    2015-10-15

    Intra-tumoral arterio-hepatic venous shunting (AHVS) poses an impediment to transarterial chemoembolization of liver tumors. Not only does it present a potential hazard for systemic shunting and embolization, but also the altered flow dynamics may also result in poor delivery of drug/embolics to the target tumor bed. Current available techniques to overcome AVHS include arterial embolization (particles, coils, glue, etc.) or temporary venous occlusion using balloons. We hereby illustrate the use of radiofrequency ablation to obliterate a complex AHVS consisting of a varix-like venous aneurysm.

  4. Congenital extrahepatic portosystemic shunt associated with heterotaxy and polysplenia

    Newman, Beverley [Lucile Packard Children' s Hospital, Department of Radiology, Stanford University School of Medicine, Stanford, CA (United States); Feinstein, Jeffrey A. [Stanford University School of Medicine, Division of Pediatric Cardiology, Department of Pediatrics, Lucile Packard Children' s Hospital, Stanford (United States); Cohen, Ronald A.; Patel, Hitendra [Children' s Hospital and Research Center, Department of Diagnostic Radiology, Oakland, CA (United States); Feingold, Brian; Kreutzer, Jacqueline [Children' s Hospital of Pittsburgh, Department of Pediatrics, Division of Pediatric Cardiology, Pittsburgh, PA (United States); Chan, Fandics P. [Stanford University School of Medicine, Cardiovascular Imaging Section, Department of Radiology, Lucile Packard Children' s Hospital, Stanford, CA (United States)

    2010-07-15

    Heterotaxy with polysplenia is associated with many cardiovascular anomalies including the occasional occurrence of congenital extrahepatic portosystemic shunts (CEPS). Missing this anomaly can lead to inappropriate and ineffective therapy. To emphasize the importance and associated anatomy of CEPS in conjunction with heterotaxy with polysplenia. Review of three young children who presented with cyanosis and pulmonary hypertension without a cardiac etiology. They were known (1) or discovered (2) to have heterotaxy with polysplenia. There was absence of the intrahepatic inferior vena cava (IVC) with azygos or hemiazygos continuation in all three cases. In spite of normal liver function, they were discovered to have large portosystemic shunts, splenorenal in location, along with diffuse peripheral pulmonary arterial dilatation suggestive of CEPS (Abernethy malformation) with hepatopulmonary or, more accurately, portopulmonary syndrome. All CEPS were ipsilateral to the spleens. Patency of the portal veins in these cases allowed for percutaneous shunt closure with resolution of cyanosis. CEPS is associated with heterotaxy with polysplenia and can be symptomatic because of pulmonary arteriovenous (AV) shunting. Portal and hepatic vein patency are critical for determining feasibility of CEPS closure. (orig.)

  5. Longitudinal Shunt Slot Excitation by Wiggly Ridge Substrate Integrated Waveguide

    Mehdi Salemi

    2014-07-01

    Full Text Available Application of a substrate integrated waveguide with wiggly ridge shape is presented for excitation longitudinal shunt slot antenna. Two main design equations for design substrate integrated waveguide structure and get parameters of structures, for longitudinal shunt slot excitation by shape wiggly ridge in substrate integrated waveguide are modified. Proposed method is used by applied the crinkle shape to ridge for ridge substrate integrated waveguide structure. This shape wiggly ridge just under longitudinal slot. The slot is place at centreline of substrate integrated waveguide (siw in center of waveguide and on dielectric copper surface, top of substrate integrated waveguide. Amount of crinkle depth of waveguide centreline is proportional with needful radiation of slot and normalized conductance could be much to increase crinkle depth. In this paper the shunt element distribution assumption for prposed structure is spoted. Results of simulation show, proposed method is suitable candidate for replacing with usual longitudinal shunt slot. Structure’s useful is, low fabrication price, small profile and adaptation with microstrip circuit. Also slot place along waveguide centerline and wiggle depth substitute slot offset, therefore this procedure can suppress second order bim in array containing suggestion structure.

  6. Peritoneo-vulvar catheter extrusion after shunt operation.

    Nagulic, M; Djordjevic, M; Samardzic, M

    1996-04-01

    We report an unusual case of catheter extrusion through the external genitalia. between the labium majus and the labium minus, in a 6-month-old hydrocephalic baby. The event occurred 5 months after placement of a ventriculoperitoneal shunt. PMID:8739410

  7. Factorial analysis in diagnosis of left-to-right shunts

    Factor analysis (FA) extracts curves and images from a dynamic study with minimal operator intervention. This study applies FA to the left-to-right (L-R) shunt diagnosis, using it with deconvolution and gamma fitting techniques and comparing it to current procedures. 14 patients with a L-R shunt confirmed by catheterization and 10 normal subjects were studied. A first-pass ventriculogram was gathered in list mode for 25 sec after bolus injection of 15-20 mCi Tc99m. .5 sec frames were created. For FA 3 factors were requested, the dixel size was 4 by 4 pixels and 30 dixels were analyzed. The heart was masked out for the analysis. Three images and curves were obtained: venous input, lungs and background. The lung curve was deconvolved by the venous input curve using the lagged normal algorithm. The unit impulse response was used to obtain a calculated output lung curve. Gamma functions were fitted on this curve and area ratios yielded the Qp/Qs. Only FA with deconvolution separates the shunt patients from the control group with a p <0.001. Qp/Qs for the shunt group was 2.30, SD .54 and the control group was 1.12, SD .07. The best correlation with oximetry was obtained with this technique, r=.87 and SEE .28. The FA lung curve has excellent counting statistics derived from 48% of the total counts, thus the improvement of results

  8. Large area shunt defect free GaAs solar cells

    Shunt defects have been found to be the type of defect that can degrade and cause failure in GaAs solar cells. Because of their catastrophic effects, it is necessary to insure that no shunt defects are formed in the solar cell. A technique for fabricating large area shunt defect free GaAs solar cells has been investigated. A Be doped GaAlAs window layer was grown directly on a n-type GaAs substrate by isothermal liquid phase epitaxial growth (ILPE). By growing directly on the GaAs substrate and not growing the usual buffer, absorber, collector, and window layer combination, the fabrication is simplified and yields can be large. It was found that the Be from the liquid GaAlAs melt diffused into the GaAs to form a complete collector layer. Because the collector is complete, a shunt defect free solar cell is produced. The results of the ILPE growth are reported for both 5.1 cm2 and 0.12 cm2 solar cells. The technique is very versatile and may be used to fabricate larger area solar cells

  9. Assessment of surgical portosystemic shunts and associated complications: The diagnostic and therapeutic role of radiologists

    Taslakian, Bedros, E-mail: btaslakian@gmail.com [Department of Radiology, American University of Beirut Medical Center, Riad El-Solh 1107 2020—PO Box: 11-0236, Beirut (Lebanon); Faraj, Walid, E-mail: wf07@aub.edu.lb [Department of General Surgery, American University of Beirut Medical Center, Riad El-Solh 1107 2020—PO Box: 11-0236, Beirut (Lebanon); Khalife, Mohammad, E-mail: mk12@aub.edu.lb [Department of General Surgery, American University of Beirut Medical Center, Riad El-Solh 1107 2020—PO Box: 11-0236, Beirut (Lebanon); Al-Kutoubi, Aghiad, E-mail: mk00@aub.edu.lb [Department of Radiology, American University of Beirut Medical Center, Riad El-Solh 1107 2020—PO Box: 11-0236, Beirut (Lebanon); El-Merhi, Fadi, E-mail: fe19@aub.edu.lb [Department of Radiology, American University of Beirut Medical Center, Riad El-Solh 1107 2020—PO Box: 11-0236, Beirut (Lebanon); Saade, Charbel, E-mail: cs39@aub.edu.lb [Department of Radiology, American University of Beirut Medical Center, Riad El-Solh 1107 2020—PO Box: 11-0236, Beirut (Lebanon); Hallal, Ali, E-mail: ah05@aub.edu.lb [Department of General Surgery, American University of Beirut Medical Center, Riad El-Solh 1107 2020—PO Box: 11-0236, Beirut (Lebanon); Haydar, Ali, E-mail: ah24@aub.edu.lb [Department of Radiology, American University of Beirut Medical Center, Riad El-Solh 1107 2020—PO Box: 11-0236, Beirut (Lebanon)

    2015-08-15

    Highlights: • Portal hypertension is the pathological increase in portal venous pressure. • Surgical portosystemic shunting is an accepted methods to decrease portal venous pressure. • Surgical portosystemic shunts are divided into selective and nonselective. • Shunt thrombosis is a serious complication, resulting in shunt dysfunction. • Imaging is essential in the assessment of the shunt function and anatomy. - Abstract: Surgical portosystemic shunting, the formation of a vascular connection between the portal and systemic venous circulation, has been used as a treatment to reduce portal venous pressure. Although the use of portosystemic shunt surgery in the management of portal hypertension has declined during the past decade in favour of alternative therapies, and subsequently surgeons and radiologists became less familiar with the procedure, it remains a well-established treatment. Knowledge of different types of surgical portosystemic shunts, their pathophysiology and complications will help radiologists improve communication with surgeons and enhance their understanding of the diagnostic and therapeutic role of radiology in the assessment and management of these shunts. Optimal assessment of the shunt is essential to determine its patency and allow timely intervention. Both non-invasive and invasive imaging modalities complement each other in the evaluation of surgical portosystemic shunts. Interventional radiology plays an important role in the management of complications, such as shunt thrombosis and stenosis. This article describes the various types of surgical portosystemic shunts, explains the anatomy and pathophysiology of these shunts, illustrates the pearls and pitfalls of different imaging modalities in the assessment of these shunts and demonstrates the role of radiologists in the interventional management of complications.

  10. Assessment of surgical portosystemic shunts and associated complications: The diagnostic and therapeutic role of radiologists

    Highlights: • Portal hypertension is the pathological increase in portal venous pressure. • Surgical portosystemic shunting is an accepted methods to decrease portal venous pressure. • Surgical portosystemic shunts are divided into selective and nonselective. • Shunt thrombosis is a serious complication, resulting in shunt dysfunction. • Imaging is essential in the assessment of the shunt function and anatomy. - Abstract: Surgical portosystemic shunting, the formation of a vascular connection between the portal and systemic venous circulation, has been used as a treatment to reduce portal venous pressure. Although the use of portosystemic shunt surgery in the management of portal hypertension has declined during the past decade in favour of alternative therapies, and subsequently surgeons and radiologists became less familiar with the procedure, it remains a well-established treatment. Knowledge of different types of surgical portosystemic shunts, their pathophysiology and complications will help radiologists improve communication with surgeons and enhance their understanding of the diagnostic and therapeutic role of radiology in the assessment and management of these shunts. Optimal assessment of the shunt is essential to determine its patency and allow timely intervention. Both non-invasive and invasive imaging modalities complement each other in the evaluation of surgical portosystemic shunts. Interventional radiology plays an important role in the management of complications, such as shunt thrombosis and stenosis. This article describes the various types of surgical portosystemic shunts, explains the anatomy and pathophysiology of these shunts, illustrates the pearls and pitfalls of different imaging modalities in the assessment of these shunts and demonstrates the role of radiologists in the interventional management of complications

  11. Multidetector row CT study of percutaneous transhepatic intrahepatic portosystemic shunt

    Objective: To investigate imaging features of the liver, portal vein and hepatic vein or transhepatic inferior vena cava in patients with severe liver cirrhosis in multidetector row computed tomography (MDCT), and assess the feasibility, safety and clinical significance of percutaneous transhepatic intrahepatic portosystemic, shunt (PTIPS). Methods: Fifty patients with severe liver cirrhosis confirmed by clinical data and imaging examination were enrolled in this study. Simulation of intrahepatic portosystemic shunt by percutaneous transhepatic, approach is as follows. The right midaxillary line (the eighth oi ninth intercostal space) was selected as puncture point A the right branch of portal vein was puncture point B, transhepatic inferior vena cava was puncture point C, and the distal part of right portal vein was D. A-B-C connection is simulated as percutaneous transhepatic puncture tract, C-B-D connection is simulated as portosystemic shunt tract. After tri-phase contrast-enhanced CT scanning, postprocessing images through multiple planner reconstruction (MPR) were obtained. The data were indicated statistically by x-bar±s. And 9.5% confidence interval for mean was calculated. Anatomic relationship among the right portal vein, transhepatic inferior vena cava, hepatic artery and bile duct were analyzed for all patients. Results: The length of the needle (A-B-C) is (145.7±14.8) mm. The curvature of the needle (the angle of A-B line and B-C line) is (145.0±9.9) . The length of transhepatic shunt tract (B-C) is (42.7±7.2) mm. The length of the shunt tract (C-B-D) is (117.7±11.6) mm; The angle of the shunt tract (the angle of B-C line and B-D line) is (108.5±5.9)°. In 24/50 patients, transhepatic inferior vena cava locate in the dorsal of the right portal vein, in 26/50 patients they are in the same plane. In all patients, the right branches of hepatic artery and bile duct locate in the ventral of the right portal vein. Conclusion: The procedure of PTIPS is

  12. Right-to-left shunt with hypoxemia in pulmonary hypertension

    Mastroïanni Bénédicte

    2009-03-01

    Full Text Available Abstract Background Hypoxemia is common in pulmonary hypertension (PH and may be partly related to ventilation/perfusion mismatch, low diffusion capacity, low cardiac output, and/or right-to-left (RL shunting. Methods To determine whether true RL shunting causing hypoxemia is caused by intracardiac shunting, as classically considered, a retrospective single center study was conducted in consecutive patients with precapillary PH, with hypoxemia at rest (PaO2 2 (AaPO2, and with transthoracic contrast echocardiography performed within 3 months. Results Among 263 patients with precapillary PH, 34 patients were included: pulmonary arterial hypertension, 21%; PH associated with lung disease, 47% (chronic obstructive pulmonary disease, 23%; interstitial lung disease, 9%; other, 15%; chronic thromboembolic PH, 26%; miscellaneous causes, 6%. Mean pulmonary artery pressure, cardiac index, and pulmonary vascular resistance were 45.8 ± 10.8 mmHg, 2.2 ± 0.6 L/min/m2, and 469 ± 275 dyn.s.cm-5, respectively. PaO2 in room air was 6.8 ± 1.3 kPa. Qs/Qt was 10.2 ± 4.2%. AaPO2 under 100% oxygen was 32.5 ± 12.4 kPa. Positive contrast was present at transthoracic contrast echocardiography in 6/34 (18% of patients, including only 4/34 (12% with intracardiac RL shunting. Qs/Qt did not correlate with hemodynamic parameters. Patients' characteristics did not differ according to the result of contrast echocardiography. Conclusion When present in patients with precapillary PH, RL shunting is usually not related to reopening of patent foramen ovale, whatever the etiology of PH.

  13. Multidisciplinary team malfunctioning on a state hospital unit: a case study.

    Gomez, E A; Ruiz, P; Langrod, J

    1980-01-01

    The use of multidisciplinary teams in the care of psychiatric patients can be countertherapeutic unless attention is paid to the dynamics of team functioning. The authors present a case study of team malfunctioning on an inpatient unit in a state hospital that resulted from staff's role confusion and insecurity. Patient care was relegated to second place as major interpersonal conflicts among the staff were played out along ethnic and cultural lines. Resolution of the conflicts required identifying their source, clarifying staff roles, and initiating a special inservice training program focused primarily on the needs of paraprofessional staff. PMID:7353821

  14. An Experimental Study of Emission and Combustion Characteristics of Marine Diesel Engine with Fuel Injector Malfunctions

    Kowalski Jerzy

    2016-01-01

    The presented paper shows the results of the laboratory study on the relation between chosen malfunctions of a fuel injector and composition of exhaust gas from the marine engine. The object of research is a marine 3-cylinder, four-stroke, direct injection diesel engine with an intercooler system. The engine was loaded with a generator and supercharged. The generator was electrically connected to the water resistance. The engine operated with a load between 50 kW and 250 kW at a constant spee...

  15. Lumboatrial shunt in a patient with Crouzon syndrome complicated by pseudotumor cerebri.

    Sankey, Eric W; Khattab, Mohamed H; Elder, Benjamin D; Goodwin, C Rory; Rekate, Harold L; Rigamonti, Daniele

    2015-09-01

    A 25-year-old man with Crouzon syndrome complicated by pseudotumor cerebri and multiple shunt failures presented with progressive back and neck pain, intermittent headaches, and associated vomiting secondary to shunt infection. Due to his previous history of repeated failure of both ventriculoperitoneal and lumboperitoneal (LP) shunting procedures, the decision was made to place a lumboatrial (LA) shunt via an approach through the internal jugular vein. The procedure was uncomplicated and the man's symptoms were relieved. Despite significant improvement, the LA shunt limited his exercise tolerance, and as an avid runner and weight lifter, he requested reconversion back to an LP shunt. At a follow-up of 20months, he continued to do well both clinically and radiographically. This case report summarizes the successful placement and use of an LA shunt for the treatment of intracranial hypertension in the setting of Crouzon syndrome. PMID:26021731

  16. Peroral extrusion of ventriculoperitoneal shunt: Case report and review of literature

    Sridhar K

    2009-01-01

    Full Text Available A rare complication of ventriculoperitoneal shunting (VPS is bowel perforation by the peritoneal catheter of the shunt tube. Rarer still is the peroral extrusion of such a perforated shunt. A two-month-old infant with history of neonatal meningitis, presented with a large head, bulging fontanelle, and hydrocephalus. A VPS was inserted. The child was doing well till the age of eight months, when following vomiting, the peritoneal end of the shunt came out through the mouth. The shunt was removed and antibiotics started. At follow up after 12 months, the child was doing well. Peroral extrusion of the shunt tube needs prompt treatment, including removal of the extruded shunt tube, and attention to bowel perforation and possible cerebrospinal fluid infection. The reported patient is younger than the five cases reported earlier. Strategies in the management of this complication are reviewed. An individualized approach is essential for the successful treatment of this rare complication.

  17. An Enhanced Data Visualization Method for Diesel Engine Malfunction Classification Using Multi-Sensor Signals

    Yiqing Li

    2015-10-01

    Full Text Available The various multi-sensor signal features from a diesel engine constitute a complex high-dimensional dataset. The non-linear dimensionality reduction method, t-distributed stochastic neighbor embedding (t-SNE, provides an effective way to implement data visualization for complex high-dimensional data. However, irrelevant features can deteriorate the performance of data visualization, and thus, should be eliminated a priori. This paper proposes a feature subset score based t-SNE (FSS-t-SNE data visualization method to deal with the high-dimensional data that are collected from multi-sensor signals. In this method, the optimal feature subset is constructed by a feature subset score criterion. Then the high-dimensional data are visualized in 2-dimension space. According to the UCI dataset test, FSS-t-SNE can effectively improve the classification accuracy. An experiment was performed with a large power marine diesel engine to validate the proposed method for diesel engine malfunction classification. Multi-sensor signals were collected by a cylinder vibration sensor and a cylinder pressure sensor. Compared with other conventional data visualization methods, the proposed method shows good visualization performance and high classification accuracy in multi-malfunction classification of a diesel engine.

  18. Multiple components malfunction scenarios--a classification technique with emphasis on shared-cause events

    The authors of this study, under EPRI sponsorship, undertook the task of formulating a working definition for common-cause failure; however, they discovered such a wide diversity of event scenarios that no simple definition proved to be helpful. The alternative was to devise a classification system for all event scenarios, but designed with the ability to handle shared-cause phenomena. The objectives of pursuing this line of investigation are three-fold: 1) develop a logical and credible method for dissecting and understanding actual component malfunction scenarios in order to identify multiple events where the shared-cause phenomenon is important; 2) support various analyses, including probabilistic risk assessments, with a means of segregating data for use in statistical and modeling evaluations; and 3) assess the effectiveness of defensive strategies that may be employed where a need to reduce the impact of shared-cause malfunctions exists. Having established the clear distinction between root causes and component causes and between failures and functional unavailabilities, an event scenario can be readily broken down into its elementary parts wherein each component has an identifiable cause of its unavailability and each scenario has an overall classification. The heart of this system is a device called a Cause-Effect Logic Diagram which depicts the interrelationship between causes and components

  19. Different degree in proteasome malfunction has various effects on root growth possibly through preventing cell division and promoting autophagic vacuolization.

    Xianyong Sheng

    Full Text Available The ubiquitin/proteasome pathway plays a vital role in plant development. But the effects of proteasome malfunction on root growth, and the mechanism underlying this involvement remains unclear. In the present study, the effects of proteasome inhibitors on Arabidopsis root growth were studied through the analysis of the root length, and meristem size and cell length in maturation zone using FM4-64, and cell-division potential using GFP fusion cyclin B, and accumulation of ubiquitinated proteins using immunofluorescence labeling, and autophagy activity using LysoTracker and MDC. The results indicated that lower concentration of proteasome inhibitors promoted root growth, whereas higher concentration of inhibitors had the opposite effects. The accumulation of cyclin B was linked to MG132-induced decline in meristem size, indicating that proteasome malfunction prevented cell division. Besides, MG132-induced accumulation of the ubiquitinated proteins was associated with the increasing fluorescence signal of LysoTracker and MDC in the elongation zone, revealing a link between the activation of autophagy and proteasome malfunction. These results suggest that weak proteasome malfunction activates moderate autophagy and promotes cell elongation, which compensates the inhibitor-induced reduction of cell division, resulting in long roots. Whereas strong proteasome malfunction induces severe autophagy and disturbs cell elongation, resulting in short roots.

  20. Management of intracranial dural arteriovenous shunts in adults

    Sarma, Dipanka; Brugge, Karel ter E-mail: karel.terbrugge@uhn.on.ca

    2003-06-01

    Dural arteriovenous shunts are abnormal arteriovenous communications within the dura. They are thought to be an acquired condition in adults and can present with a variety of clinical features, ranging from benign bruits to intracranial hemorrhage and neurological deficits. The presentation and natural history of these shunts is largely determined by the pattern of venous drainage. Knowledge of natural history and careful study of the angioarchitexture by angiography is therefore mandatory for correct management of these lesions. In this review, principles of management in adults and the various factors that influence treatment decisions are discussed, with a focus on endovascular therapy. Retrograde leptomeningeal or cortical venous drainage has a strong correlation with adverse clinical events and the requirement for aggressive management in this situation is highlighted. Indications for endovascular treatment, therapeutic goals, approaches and techniques are reviewed. The role of surgical treatment is also briefly discussed.

  1. Management of intracranial dural arteriovenous shunts in adults

    Dural arteriovenous shunts are abnormal arteriovenous communications within the dura. They are thought to be an acquired condition in adults and can present with a variety of clinical features, ranging from benign bruits to intracranial hemorrhage and neurological deficits. The presentation and natural history of these shunts is largely determined by the pattern of venous drainage. Knowledge of natural history and careful study of the angioarchitexture by angiography is therefore mandatory for correct management of these lesions. In this review, principles of management in adults and the various factors that influence treatment decisions are discussed, with a focus on endovascular therapy. Retrograde leptomeningeal or cortical venous drainage has a strong correlation with adverse clinical events and the requirement for aggressive management in this situation is highlighted. Indications for endovascular treatment, therapeutic goals, approaches and techniques are reviewed. The role of surgical treatment is also briefly discussed

  2. Cerebral venous thrombosis after ventriculoperitoneal shunting: a case report.

    Matsubara, Teppei; Ayuzawa, Satoshi; Aoki, Tsukasa; Ikeda, Go; Shiigai, Masanari; Matsumura, Akira

    2014-01-01

    Ventriculoperitoneal shunting (VPS) is a simple procedure, but there are several potential complications. We describe the first reported case of cerebral venous thrombosis (CVT) after VPS. A 69-year-old man suffering from normal pressure hydrocephalus underwent left VPS. Two months later he developed CVT and cerebral venous hemorrhage in the left frontal lobe. Computed tomography (CT) and magnetic resonance imaging (MRI) revealed the thrombus formation just adjacent to the shunt tube. One possible cause is compression of the cortical vein after brain shift and/or tension of the cortical vein due to intracranial hypotension. A protein C deficiency was also detected. Surgeons should be aware that cerebral venous thrombosis can occur after VPS. PMID:24257484

  3. [Surgical treatment of refractory ascites with peritoneovenous shunt].

    Massari, R; Fulgente, R; Marinelli, S; Romessis, M

    1995-01-01

    Leveen and associates described a peritoneo-venous shunt which proved to be useful in patients with intractable ascites. Medical therapy, paracentesis and peritoneovenous shunt have been compared, but there is uncertainty about their relative merits. Therefore, the leveen device has be placed in last years in an increasing number of patients: it has not been shown by prospective trials to prolong survival significantly, although it may shorten hospitalization and improve the quality of life. A number of early and late complications were described but they do not influence the general results: origin and features of such complications are discussed as well as their prevention and treatment and personal cases are presented. Selection of patients and careful surgical procedure seems to be mandatory for better results. PMID:8706187

  4. A Technique for Shunt Active Filter meld micro grid System

    A. Lumani

    2015-08-01

    Full Text Available The proposed system presents a control technique for a micro grid connected hybrid generation system ith case study interfaced with a three phase shunt active filter to suppress the current harmonics and reactive power present in the load using PQ Theory with ANN controller. This Hybrid Micro Grid is developed using freely renewable energy resources like Solar Photovoltaic (SPV and Wind Energy (WE. To extract the maximum available power from PV panels and wind turbines, Maximum power point Tracker (MPPT has been included. This MPPT uses the “Standard Perturbs and Observe” technique. By using PQ Theory with ANN Controller, the Reference currents are generated which are to be injected by Shunt active power filter (SAPFto compensate the current harmonics in the non linear load. Simulation studies shows that the proposed control technique performs non-linear load current harmonic compensation maintaining the load current in phase with the source voltage.\\

  5. Endoscopic third ventriculostomy has no higher costs than ventriculoperitoneal shunt

    Benicio Oton de Lima

    2014-07-01

    Full Text Available Objective: To evaluate the cost of endoscopic third ventriculostomy (ETV compared to ventriculoperitoneal shunt (VPS in the treatment of hydrocephalus in children. Method: We studied 103 children with hydrocephalus, 52 of which were treated with ETV and 51 with VPS in a prospective cohort. Treatment costs were compared within the first year after surgery, including subsequent surgery or hospitalization. Results: Twenty (38.4% of the 52 children treated with VPS needed another procedure due to shunt failure, compared to 11 (21.5% of 51 children in the ETV group. The average costs per patient in the group treated with ETV was USD$ 2,177,66±517.73 compared to USD$ 2,890.68±2,835.02 for the VPS group. Conclusions: In this series there was no significant difference in costs between the ETV and VPS groups.

  6. Shunted-Josephson-junction model. I. The autonomous case

    Belykh, V. N.; Pedersen, Niels Falsig; Sørensen, O. H.

    1977-01-01

    The shunted-Josephson-junction model: the parallel combination of a capacitance, a phase-dependent conductance, and an ideal junction element biased by a constant current, is discussed for arbitrary values of the junction parameters. The main objective is to provide a qualitative understanding of...... current-voltage curves are presented. The case with a time-dependent monochromatic bias current is treated in a similar fashion in the companion paper....

  7. Harmonics and Reactive Power Compensation Using Shunt Hybrid Filter

    R. Sriranjani; M. Geetha; S. Jayalalitha

    2013-01-01

    The supply current is distorted by the nonlinear load such UPS, DC drives, AC drives and arc furnace. This current harmonics derates the electrical equipments. Thus the current harmonics are reduced from the supply line using Shunt Hybrid filter. The Hysteresis controller controls the active filter thus the supply current tracks the reference fundamental current extracted by the synchronous reference frame unit. So supply current is free from harmonics and also it provides harmonic compensati...

  8. Transjugular Intrahepatic Portosystemic Shunts in Patients with Hepatic Malignancy

    Wallace, Michael J.; Madoff, David C.

    2005-01-01

    Since its first clinical application in 1988, the transjugular intrahepatic portosystemic shunt (TIPS) has emerged as a safe and effective means of managing patients with morbid portal hypertension. Despite the considerable body of literature on TIPS, portal decompression in patients with malignancy has not been sufficiently examined. These patients typically experience sequelae of portal hypertension that requires palliation. The purpose of this article is to review the reported experience w...

  9. Pre-Liver Transplant: Tips Versus Distal Splenorenal Shunt

    Thomas W. Faust

    1997-01-01

    Full Text Available Recurrent variceal bleeding in liver transplant candidates with end-stage liver disease can complicate or even prohibit a subsequent transplant procedure (OLT. Endoscopic sclero-therapy and medical therapy are considered as first-line management with surgical shunts reserved for refractory situations. Surgical shunts can be associated with a high mortality in this population and may complicate subsequent OLT. The transjugular intrahepatic portosystemic shunt (TIPS has been recommended in these patients as a bridge to OLT. This is a new modality that has not been compared with previously established therapies such as the distal splenorenal shunt (DSRS. In this study we report our experience with 35 liver transplant recipients who had a previous TIPS (18 patients or DSRS (17 patients for variceal bleeding. The TIPS group had a significantly larger proportion of critically ill and Child-Pugh C patients. Mean operating time was more prolonged in the DSRS group (P=0.014 but transfusion requirements were similar. Intraoperative portal vein blood flow measurements averaged 2132±725 ml/min in the TIPS group compared with 1120±351ml/min in the DSRS group (P<0.001. Arterial flows were similar. Mean ICU and hospital stays were similar. There were 3 hospital mortalities in the DSRS group and none in the TIPS group (P=0.1. We conclude that TIPS is a valuable tool in the management of recurrent variceal bleeding prior to liver transplantation. Intra0Perative hemodynamic measurements suggest a theoretical advantage with TIPS. In a group of patients with advanced liver disease we report an outcome that is similar to patients treated with DSRS prior to liver transplantation. The role of TIPS in the treatment of nontransplant candidates remains to be clarified.

  10. Bacteremia and "Endotipsitis" following transjugular intrahepatic portosystemic shunting

    Mizrahi Meir; Roemi Lilach; Shouval Daniel; Adar Tomer; Korem Maya; Moses Alon; Bloom Alan; Shibolet Oren

    2011-01-01

    AIM: To identify all cases of bacteremia and suspected endotipsitis after Transjugular intrahepatic portosystemic shunting (TIPS) at our institution and to determine risk factors for their occurrence. METHODS: We retrospectively reviewed records of all patients who underwent TIPS in our institution between 1996 and 2009. Data included: indications for TIPS, underlying liver disease, demographics, positive blood cultures after TIPS, microbiological characteristics, treatment and outcome. RESUL...

  11. Simulation of rectifier voltage malfunction on OWECS, four-level converter, HVDC light link: Smart grid context tool

    Highlights: • Floating offshore wind turbine in deep water. • DC link and voltage malfunction. • Converter topology considered is four-level. • Controllers are based on fractional-order. • Smart grid context. - Abstract: This paper presents a model for the simulation of an offshore wind system having a rectifier input voltage malfunction at one phase. The offshore wind system model comprises a variable-speed wind turbine supported on a floating platform, equipped with a permanent magnet synchronous generator using full-power four-level neutral point clamped converter. The link from the offshore floating platform to the onshore electrical grid is done through a light high voltage direct current submarine cable. The drive train is modeled by a three-mass model. Considerations about the smart grid context are offered for the use of the model in such a context. The rectifier voltage malfunction domino effect is presented as a case study to show capabilities of the model

  12. A Rare Complication of Ventriculo-peritoneal Shunt : The Migration of the Distal End of the Shunt into the Pleural Cavity with Hydrothorax in a Case Meningomyelocele

    We report a case of a two month old baby boy with an upper lumber meningomyelocele that was repaired one day after delivery and a right posterior parietal ventriculo-peritoneal shunt inserted at the age of two weeks for the development of hydrocephalus. The patient presented with respiratory distress was found to have CSF hydrothorax due to the migration of the distal end of the ventriculo-peritoneal shunt into the pleural cavity. The CSF was infected, this was successfully treated with the removal of the shunt, antibiotics, thoracocentesis for the presistence of the respiratory distress and insertion of a new ventriculo-peritoneal shunt. The presence of an upper lumbar meningomyelocele may play a role in weakness of the diaphragmatic muscle through which the migration of the distal end of the shunt occur, especially if no congenital defect in the diaphragm could be detected. (author) 11 refs . , 2 figs

  13. Parallel Piezoelectric Shunt Damping of Rotationally Periodic Structures

    Bilal Mokrani

    2015-01-01

    Full Text Available This paper considers the RL shunt damping of rotationally periodic structures with an array of regularly spaced piezoelectric patches. The technique is targeted to the damping of a specific mode with n nodal diameters. For this particular case, one can take advantage of the shape of the targeted mode to organize the piezoelectric patches as a modal filter (in parallel loops which reduces the demand on the inductors of the tuned inductive shunt. In the case of a perfectly rotationally periodic structure, it is possible to organize 4n piezoelectric transducers (PZT patches in two parallel loops of 2n patches each. In this way, the demand on the inductors is reduced by 4n2 as compared to independent loops, which may allow a fully passive integration of the RL shunt in a turbomachinery application. The method is first illustrated experimentally on a circular plate; it is then applied to a prototype of an industrial bladed drum. The influence of blade mistuning is investigated.

  14. Negative impedance shunted electromagnetic absorber for broadband absorbing: experimental investigation

    The traditional tuned mass absorber is widely employed to control the vibration of a primary structure by transferring the vibrating energy to the absorber. However, the working band of the absorber is very narrow, which limits the application of broadband vibration control. This study presents a novel broadband electromagnetic absorber by first introducing two negative impedance shunts to improve broadband damping of the absorber. The electromagnetic absorber is modeled, and the corresponding electromagnetic coupling coefficient is tested. A cantilever beam is employed to verify the broadband vibration absorption of the negative resistance (NR) shunted electromagnetic absorber (NR absorber) and the negative inductance NR shunted electromagnetic absorber (NINR absorber). The governing equations of the beam with two absorbers are derived, and the experiments are set up. The results point out that the NR and NINR absorbers can attenuate the broadband vibration. The proposed absorbers do not need the feedback system and the real-time controller compared to the active absorber; hence, they have great application potential in aerospace and in submarine applications, as well as in civil and mechanical engineering. (paper)

  15. Malfunctions of Implantable Cardiac Devices in Patients Receiving Proton Beam Therapy: Incidence and Predictors

    Gomez, Daniel R., E-mail: dgomez@mdanderson.org [Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Poenisch, Falk [Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Pinnix, Chelsea C. [Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Sheu, Tommy [Department of Experimental Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Chang, Joe Y. [Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Memon, Nada [Department of Cardiology, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Mohan, Radhe [Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Rozner, Marc A. [Department of Anesthesiology and Perioperative Medicine, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Dougherty, Anne H. [Department of Cardiology, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States)

    2013-11-01

    Purpose: Photon therapy has been reported to induce resets of implanted cardiac devices, but the clinical sequelae of treating patients with such devices with proton beam therapy (PBT) are not well known. We reviewed the incidence of device malfunctions among patients undergoing PBT. Methods and Materials: From March 2009 through July 2012, 42 patients with implanted cardiac implantable electronic devices (CIED; 28 pacemakers and 14 cardioverter-defibrillators) underwent 42 courses of PBT for thoracic (23, 55%), prostate (15, 36%), liver (3, 7%), or base of skull (1, 2%) tumors at a single institution. The median prescribed dose was 74 Gy (relative biological effectiveness; range 46.8-87.5 Gy), and the median distance from the treatment field to the CIED was 10 cm (range 0.8-40 cm). Maximum proton and neutron doses were estimated for each treatment course. All CIEDs were checked before radiation delivery and monitored throughout treatment. Results: Median estimated peak proton and neutron doses to the CIED in all patients were 0.8 Gy (range 0.13-21 Gy) and 346 Sv (range 11-1100 mSv). Six CIED malfunctions occurred in 5 patients (2 pacemakers and 3 defibrillators). Five of these malfunctions were CIED resets, and 1 patient with a defibrillator (in a patient with a liver tumor) had an elective replacement indicator after therapy that was not influenced by radiation. The mean distance from the proton beam to the CIED among devices that reset was 7.0 cm (range 0.9-8 cm), and the mean maximum neutron dose was 655 mSv (range 330-1100 mSv). All resets occurred in patients receiving thoracic PBT and were corrected without clinical incident. The generator for the defibrillator with the elective replacement indicator message was replaced uneventfully after treatment. Conclusions: The incidence of CIED resets was about 20% among patients receiving PBT to the thorax. We recommend that PBT be avoided in pacing-dependent patients and that patients with any type of CIED receiving

  16. Chemoembolic Hepatopulmonary Shunt Reduction to Allow Safe Yttrium-90 Radioembolization Lobectomy of Hepatocellular Carcinoma

    Gaba, Ron C., E-mail: rgaba@uic.edu [University of Illinois Medical Center at Chicago, Department of Radiology, Section in Interventional Radiology (United States); VanMiddlesworth, Kyle A. [Midwestern University School of Medicine (United States)

    2012-12-15

    Yttrium-90 ({sup 90}Y) radioembolization represents an emerging transcatheter treatment option for the management of hepatocellular carcinoma (HCC). Elevation of the hepatopulmonary shunt fraction risks nontarget radiation to the lungs and may limit the use of {sup 90}Y therapy in patients with locally advanced disease with vascular invasion, who often demonstrate increased shunting. We present two cases in which patients with HCC and portal vein invasion resulting in elevated hepatopulmonary shunt fractions underwent chemoembolic shunt closure to allow safe {sup 90}Y radioembolization. Both patients demonstrated excellent tumor response and patient survival. On this basis, we propose a role for chemoembolic reduction of the lung shunt fraction before {sup 90}Y radioembolization in patients with extensive tumor-related hepatopulmonary shunting.

  17. A multi-stack simulation of shunt currents in vanadium redox flow batteries

    Wandschneider, F. T.; Röhm, S.; Fischer, P.; Pinkwart, K.; Tübke, J.; Nirschl, H.

    2014-09-01

    A model for the shunt currents in an all-vanadium redox flow battery consisting of 3 stacks which are electrically connected in series. It is based on an equivalent circuit which treats the shunt current pathways as Ohmic resistors. The conductivity of the vanadium electrolyte has been measured for different state-of-charges in order to implement a dependency of the resistances on the state-of-charge of the system. Published results are used to validate the simulation data of a single stack. Three setups of pipe networks are evaluated using the model. The pipe connections between the stacks give rise to external shunt currents, which also increase the amount of shunt currents within the stacks. These connections also lead to a nonuniform distribution of the shunt currents. The effects of the shunt currents on the Coulombic efficiency and the energy efficiency of the system are studied by the means of the model.

  18. Evaluation of peritoneo-venous shunt patency with 99mTc-phytate

    A simple imaging procedure has been devised for patients with peritoneo-venous shunts when ascites reaccumulates and a decision must be made on whether or not to revise the shunt. We recently experienced a patient with reaccumulated ascites in whom obstruction of peritoneo-venous shunt was suspected. 5mCi of 99mTc-phytate was injected into the peritoneal cavity and imaging of the abdomen was performed 1-30 minutes later. With a proper functioning shunt, radioactivity in the liver and spleen were easily identifiable in this case. If the shunt is obstructed, tracer activity will remain in the peritoneal cavity and thus can not be identifiable in the liver or spleen. Conclusively, radionuclide methods might be very useful for evaluation of peritoneo-venous shunt patency. (Author)

  19. Evaluation of Peritoneo-venous Shunt Patency with {sup 99m}Tc-phytate

    Hur, Dal Young; Chung, June Key; Lee, Jong Suk; Lee, Chang Soo [National Medical Center, Seoul (Korea, Republic of)

    1985-09-15

    A simple imaging procedure has been devised for patients with peritoneo-venous shunts when ascites reaccumulates and a decision must be made on whether or not to revise the shunt. We recently experienced a patient with reaccumulated ascites in whom obstruction of peritoneo-venous shunt was suspected. 5 mCi of {sup 99m}Tc-phytate was injected into the peritoneal cavity and imaging of the abdomen was performed 1-30 minutes later. With a proper functioning shunt, radioactivity in the liver and spleen were easily identifiable in this case. If the shunt is obstructed, tracer activity will remain in the peritoneal cavity and thus can not be identifiable m the liver or spleen. Conclusively, radionuclide methods might be very useful for evaluation of peritoneo-venous shunt patency.

  20. Evaluation of Peritoneo-venous Shunt Patency with 99mTc-phytate

    A simple imaging procedure has been devised for patients with peritoneo-venous shunts when ascites reaccumulates and a decision must be made on whether or not to revise the shunt. We recently experienced a patient with reaccumulated ascites in whom obstruction of peritoneo-venous shunt was suspected. 5 mCi of 99mTc-phytate was injected into the peritoneal cavity and imaging of the abdomen was performed 1-30 minutes later. With a proper functioning shunt, radioactivity in the liver and spleen were easily identifiable in this case. If the shunt is obstructed, tracer activity will remain in the peritoneal cavity and thus can not be identifiable m the liver or spleen. Conclusively, radionuclide methods might be very useful for evaluation of peritoneo-venous shunt patency.

  1. A RARE CASE OF BOWEL PERFORATION SECONDARY TO VENTRICULO PERITONEAL SHUNT

    Aditya Pratap

    2014-10-01

    Full Text Available Bowel perforation is an unusual complication of ventriculo peritoneal shunt. We are presenting a case of 15 month old male child with the shunt tubing protruding through the anus associated with bowel perforation. This complication occurred after the 13 months of insertion of ventriculo peritoneal shunt for congenital hydrocephalus. There were no signs of meningitis but mild signs of peritonitis were present. At laparotomy the tube was seen to enter the sigmoid colon and was encapsulated by the greater omentum. The tube was cut and the distal end removed via the anus. Proximal part of shunt also removed because there was contralateral shunt present. Perforation was repaired. We are here in presenting a rare complication of VP shunt.

  2. Gold shunt for refractory advanced low-tension glaucoma with spared central acuity

    Le R

    2016-03-01

    Full Text Available Ryan Le,1 Neeru Gupta1–3 1Keenan Research Center, Li Ka Shing Knowledge Institute, St. Michael’s Hospital, Toronto, ON, Canada; 2Ophthalmology and Vision Sciences, Glaucoma Unit, St. Michael’s Hospital, University of Toronto, Toronto, ON, Canada; 3Laboratory Medicine and Pathobiology, St. Michael's Hospital, University of Toronto, Toronto, ON, CanadaAbstract: The aim of this study is to report a case of gold shunt surgery for uncontrolled, low-tension glaucoma with good central vision, after having a previously failed trabeculectomy and tube shunt surgeries. The patient was receiving maximum medical glaucoma therapy of four different types with intraocular pressure of 17 mm Hg prior to gold shunt surgery. Five years later, intraocular pressure is well controlled in the low teens without the need for ocular medications, and glaucoma is stable following gold shunt surgery.Keywords: gold shunt, refractory glaucoma, glaucoma surgery, trabeculectomy, suprachoroidal space, tube shunt

  3. A new shunt DC active filter of power supply in a steady high magnetic field facility

    A DC active power filter is an indispensable part in a high power and high stability power supply system, especially in the power supply system of the Steady High Magnetic Field Facility, which requires that the current ripple should be limited to 50 parts per million. In view of the disadvantages of the series DC active power filter and shunt Pulse Width Modulation DC active filter, this paper puts forward a novel DC active filter by combining the advantages of the transistor regulator and the shunt type. The structure and principle of the new shunt linear active filter are introduced. Meanwhile, the design of several key components that construct the new shunt linear active filter is also analyzed. The simulation model and an experimental prototype of the shunt linear active filter are developed, and the results verify that the parameter design is reasonable and the shunt active filter has a good filter effect. (authors)

  4. Laparoscopic assisted ventriculoperitoneal shunt revisions as an option for pediatric patients with previous intraabdominal complications

    Fernanda O. de Carvalho

    2014-04-01

    Full Text Available Multiple shunt failure is a challenge in pediatric neurosurgery practice and one of the most feared complications of hydrocephalus. Objective: To demonstrate that laparoscopic procedures for distal ventriculoperitoneal shunt failure may be an effective option for patients who underwent multiple revisions due to repetitive manipulation of the peritoneal cavity, abdominal pseudocyst, peritonitis or other situations leading to a “non reliable” peritoneum. Method: From March 2012 to February 2013, the authors reviewed retrospectively the charts of six patients born and followed up at our institution, which presented with previous intra-peritoneal complications and underwent ventriculoperitoneal shunt revision assisted by video laparoscopy. Results: After a mean follow-up period of nine months, all patients are well and no further shunt failure was identified so far. Conclusion: Laparoscopy assisted shunt revision in children may be, in selected cases, an effective option for patients with multiple peritoneal complications due to ventriculo-peritoneal shunting.

  5. Comparison of Common Methods in Dynamic Response Predictions of Rotor Systems with Malfunctions

    Hongliang Yao

    2014-01-01

    Full Text Available The efficiency and accuracy of common time and frequency domain methods that are used to simulate the response of a rotor system with malfunctions are compared and analyzed. The Newmark method and the incremental harmonic balance method are selected as typical representatives of time and frequency domain methods, respectively. To improve the simulation efficiency, the fixed interface component mode synthesis approach is combined with the Newmark method and the receptance approach is combined with the incremental harmonic balance method. Numerical simulations are performed for rotor systems with single and double frequency excitations. The inherent characteristic that determines the efficiency of the two methods is analyzed. The results of the analysis indicated that frequency domain methods are suitable single and double frequency excitation rotor systems, whereas time domain methods are more suitable for multifrequency excitation rotor systems.

  6. Analysis of generator bearing vibration data for diagnosing rotor circuit malfunction in DFIGs

    Skrimpas, Georgios Alexandros; Sweeney, Christian W.; Jensen, Bogi Bech;

    2014-01-01

    this paper generator bearing vibration signature for a DFIG under operation with one rotor phase coil open is analysed and presented. Further this failure mode is compared to rotor dynamics fault, such as rotational looseness, and the difference in signature is discussed. Vibration data from a multi...... end and non-drive end bearings, meeting the requirements of numerous turbine operators for condition based maintenance. In a DFIG the voltage applied to the rotor is controlled by a converter, where electric connection between the two is accom- plished by using slip rings. Improper connection between...... the slip ring unit and the rotor circuit is manifested as excessive vibration seen in both ends of the generator. The consistent and accurate diagnosis of a rotor circuit malfunction is of crucial importance in regards to proper troubleshooting of the fault and the overall health of the generator. In...

  7. Electrospun polyurethane as an alternative ventricular catheter and in vitro model of shunt obstruction

    Suresh, Supraja; Black, Richard A

    2015-01-01

    Intracranial pressure and volume vary considerably between hydrocephalic patients, and with age, health and haemodynamic status; if left untreated, intracranial pressure rises and the ventricular system expands to accommodate the excess cerebrospinal fluid, with significant morbidity and mortality. Cerebrospinal fluid shunts in use today have a high incidence of failure with shunt obstruction being the most serious. Conventional proximal shunt catheters are made from poly(dimethyl)siloxane, t...

  8. Aging and malfunction of valves in CANDU special safety systems. Phase 1

    Aging and wear related valve malfunctions have been reported in American nuclear generating systems. This report documents the first attempt to study these phenomena on a global basis in Canadian nuclear power plants. A general methodology outlines an approach to this type of study which is amenable to use within existing information structures. Nuclear regulatory requirements which influence the testing of valves in Canadian nuclear power plants are reviewed. The reporting systems which emanate from these requirements are discussed and sources of valve failure data are reviewed. It is determined that modifications to existing failure reporting systems are required before practical means of collecting data necessary for the analysis of age related valve malfunctions can be developed. In spite of limitations in reported failure data, a partial data base is compiled for valve failures in Special Safety Systems of domestic nuclear plants. Data are reported for the period 1982 to 1986. The valve population and basic parameters of each valve such as type, operator, function, etc., and the reported failures against this population are compiled and reviewed for evidence of time dependent versus random failure trends. Results suggest that there is no clear age related failure trend. In fact, some systems and stations, experienced a reduction in failure rates with years of servicing, suggesting that some earlier generic valve problems may have been solved. Present inspection, test, and maintenance practices are reviewed and their effectiveness for purposes of predicting or preventing incipient failures is assessed to be of moderate value. Modern failure prevention methods are highlighted and their applicability discussed

  9. The role of persistent foramen ovale and other shunts in decompression illness.

    Wilmshurst, Peter T

    2015-06-01

    A persistent foramen ovale (PFO) and other types of right-to-left shunts are associated with neurological, cutaneous and cardiovascular decompression illness (DCI). A right-to-left shunt is particularly likely to be implicated in causation when these types of DCI occur after dives that are not provocative. It is believed that venous nitrogen bubbles that form after decompression pass through the shunt to circumvent the lung filter and invade systemic tissues supersaturated with nitrogen (or other inert gas) and as a result there is peripheral amplification of bubble emboli in those tissues. Approximately a quarter of the population have a PFO, but only a small proportion of the population with the largest right-to-left shunts are at high risk of shunt-mediated DCI. The increased risk of DCI in people with migraine with aura is because migraine with aura is also associated with right-to-left shunts and this increased risk of DCI appears to be confi ned to those with a large PFO or other large shunt. Various ultrasound techniques can be used to detect and assess the size of right-to-left shunts by imaging the appearance of bubble contrast in the systemic circulation after intravenous injection. In divers with a history of shunt-mediated DCI, methods to reduce the risk of recurrence include cessation of diving, modification of future dives to prevent venous bubble liberation and transcatheter closure of a PFO. PMID:26165532

  10. Gold shunt for refractory advanced low-tension glaucoma with spared central acuity

    Le, Ryan; Gupta, Neeru

    2016-01-01

    The aim of this study is to report a case of gold shunt surgery for uncontrolled, low-tension glaucoma with good central vision, after having a previously failed trabeculectomy and tube shunt surgeries. The patient was receiving maximum medical glaucoma therapy of four different types with intraocular pressure of 17 mm Hg prior to gold shunt surgery. Five years later, intraocular pressure is well controlled in the low teens without the need for ocular medications, and glaucoma is stable following gold shunt surgery. PMID:27051320

  11. Using Noninvasive Brain Measurement to Explore the Psychological Effects of Computer Malfunctions on Users during Human-Computer Interactions

    Leanne M. Hirshfield

    2014-01-01

    Full Text Available In today’s technologically driven world, there is a need to better understand the ways that common computer malfunctions affect computer users. These malfunctions may have measurable influences on computer user’s cognitive, emotional, and behavioral responses. An experiment was conducted where participants conducted a series of web search tasks while wearing functional near-infrared spectroscopy (fNIRS and galvanic skin response sensors. Two computer malfunctions were introduced during the sessions which had the potential to influence correlates of user trust and suspicion. Surveys were given after each session to measure user’s perceived emotional state, cognitive load, and perceived trust. Results suggest that fNIRS can be used to measure the different cognitive and emotional responses associated with computer malfunctions. These cognitive and emotional changes were correlated with users’ self-report levels of suspicion and trust, and they in turn suggest future work that further explores the capability of fNIRS for the measurement of user experience during human-computer interactions.

  12. Badness, madness and the brain - the late 19th-century controversy on immoral persons and their malfunctioning brains

    Schirmann, Felix

    2013-01-01

    In the second half of the 19th-century, a group of psychiatric experts discussed the relation between brain malfunction and moral misconduct. In the ensuing debates, scientific discourses on immorality merged with those on insanity and the brain. This yielded a specific definition of what it means t

  13. Measurements of quantum noise in resistively shunted Josephson junctions

    Measurements have been made of the low-frequency spectral density of the voltage noise in current-biased resistively shunted Josephson tunnel junctions under conditions in which the noise mixed down from frequencies near the Josephson frequency (ν/sub J/) to the measurement frequency (k/sub B/T. In this limit, quantum corrections to the mixed-down noise are important. The spectral densities measured on junctions with current-voltage characteristics close to the Stewart-McCumber model were in excellent agreement with the predicted values, with no fitted parameters. The mixed-down noise for a wide range of bias voltages was used to infer the spectral density of the current noise in the shunt resistor at frequency ν. With no fitted parameters, this spectral density at frequencies up to 500 GHz was in excellent agreement with the prediction (2hν/R)coth(hν/2k/sub B/T). The presence of the zero-point term, 2hν/R, at frequencies hν>k/sub B/T was clearly demonstrated. The current-voltage characteristics of a junction with β/sub L/equivalent2πL/sub s/I0/Phi0approx.1 and β/sub C/equivalent2πI0R2C/Phi00 is the critical current, C is the junction capacitance, and L/sub s/ is the shunt inductance, showed structure at voltages where the Josephson frequency was near a subharmonic of the L/sub s/C resonant frequency. The additional nonlinearity of the I-V characteristic caused mixing down of noise near higher harmonics of the Josephson frequency, thereby greatly enhancing the voltage noise. The measured noise was in good agreement with that predicted by computer simulations

  14. Clinical results of the transjugular intrahepatic portosystemic shunt

    To evaluate the clinical results of transjugular intrahepatic portosystemic shunt(TIPS) for the control of variceal bleeding. TIPS creation was attempted in 23 patients with endoscopically confirmed variceal bleeding. Most patients had multiple episodes of bleeding in the past and have been treated with multiple endoscopic sclerotherapies. Pre-and post-procedural hepatic and portal vein pressures were measured. After creation of TIPS patients were followed up at regular intervals. TIPS has been successfully accomplished in 22 of 23 patients using Wallstent(n = 21) and Strecker stent(n = 1). Immediate bleeding control was achieved in all patients with shunt creation. No procedure-related complication was noted. Portal vein pressure was reduced from 30.7 ± 5.8 mmHg to 20.8 ± 4.7 mmHg. The mean pressure gradient of portosystemic shunt dropped from 22.8 ± 6.0 prior to TIPS to 12.2 ± 4.1 immediately after. During the follow-up period (6-556 days, mean; 10 months), seven patients died; progressive hepatic failure (n 4), variceal rebleeding (n = 2), and respiratory failure(n = 1). Hepatic encephalopathy after TIPS was noted in 7 patients(31.8%). Variceal rebleeding occurred in 3 patients(13.6%). The remaining 15 patients have survived an average of 11 months. This results suggest that TIPS is a safe and effective method for lowering portal pressure and controlling variceal bleeding. Furthermore if these initial results are encouraged by further long-term observation, TIPS could replace endoscopic and risky surgical intervention

  15. Clinical Efficiency of Interventional Radiological Therapy in the Treatment of Obstructed Hemodialysis Shunts

    Hadi Zomorrodian

    2011-05-01

    Full Text Available Background/Objective: Analysis of the clinical"neffectiveness of endovascular radiological interventions"nin the treatment of dysfunctional dialysis shunts."nPatients and Methods: During a 3 year period, 459"ninterventional radiological procedures were performed"nin hemodialysis shunt dysfunctions in 222 patients"n(123 men, 99 women; mean age, 68.7±9.7 years. 72.1%"n(n=160 of the patients had an autologous venous graft"nand 27.9% (n=62 of the patients had a PTFE graft. In"na retrospective analysis, the primary technical success"nrate, clinical success rate, complication rate and postinterventional"npatency rates were calculated with a"nfollow-up period ranging from 0.5 to 11 years."nResults: Endovascular shunt treatments were"ntechnically successful in 98% and clinically successful"nin 97%. Minor complications occurred in 1.9% and"nmajor complications in 1.2%. Six (12 months after"ntreatment 35% (15% of the shunts were still patent"n(primary postinterventional patency rate. The"nsecondary postinterventional patency rate (including"nrepetitive interventions was 60% after 12 months and"n28% after 24 months following the first time shunt"ntreatment. The cumulative patency rate was 81%"nafter12 months, 63% after 24 months and 44% after 36"nmonths following the implantation of the shunt graft."nHence, radiological intervention allowed doubling of"nthe functional life of dysfunctional shunts."nConclusion: Radiological shunt intervention"nsignificantly increased the functional life of"ndysfunctional shunts. High technical and clinical"nsuccess rates allowed the use of almost all shunts"nfor hemodialysis immediately after treatment. The"ninterventional endovascular procedure is an effective"nand safe treatment method in the life-threatening"nsituation of a shunt dysfunction.

  16. RHIC INSERTION REGION, SHUNT POWER SUPPLY CURRENT ERRORS

    The Relativistic Heavy Ion Collider (RHIC) was commissioned in 1999 and 2000. RHIC requires power supplies to supply currents to highly inductive superconducting magnets. The RHIC Insertion Region contain's many shunt power supplies to trim the current of different magnet elements in a large superconducting magnet circuit. Power Supply current error measurements were performed during the commissioning of RHIC. Models of these power supply systems were produced to predict and improve these power supply current errors using the circuit analysis program MicroCap V by Spectrum Software (TM). Results of the power supply current errors are presented from the models and from the measurements performed during the commissioning of RHIC

  17. Shunted-Josephson-junction model. II. The nonautonomous case

    Belykh, V. N.; Pedersen, Niels Falsig; Sørensen, O. H.

    1977-01-01

    . The mathematical discussion makes use of the phase-space representation of the solutions to the differential equation. The behavior of the trajectories in phase space is described for different characteristic regions in parameter space and the associated features of the junction IV curve to be...... expected are pointed out. The main objective is to provide a qualitative understanding of the junction behavior, to clarify which kinds of properties may be derived from the shunted-junction model, and to specify the relative arrangement of the important domains in the parameter-space decomposition....

  18. [PERITONEAL VENOUS SHUNT IN THE TREATMENT OF MALIGNANTASCITIS: PRELIMINARY REPORT

    Brazzini, Augusto; Cantella, Raúl

    1998-01-01

    The present study, mentions the use of a valve for the drainage os ascitic fluid, better known as the peritoneo venous shunt, as a paliation treatment in terminal oncologic patients. It was performed in four patients with diseminated carcinomas, of diferent primary ethiology. These patients had a bad life quality, because when admitted in our Radiology suite, the clinical examination showed shortness of breathearly saciety, lethargy, and were found handiccapped to perform their habitual skills. This is a short and preliminar series, but it is an encouraging report, because, the quality of life, our goal, is improved. PMID:12209221

  19. Shunting arc plasma source for pure carbon ion beama)

    Koguchi, H.; Sakakita, H.; Kiyama, S.; Shimada, T.; Sato, Y.; Hirano, Y.

    2012-02-01

    A plasma source is developed using a coaxial shunting arc plasma gun to extract a pure carbon ion beam. The pure carbon ion beam is a new type of deposition system for diamond and other carbon materials. Our plasma device generates pure carbon plasma from solid-state carbon material without using a hydrocarbon gas such as methane gas, and the plasma does not contain any hydrogen. The ion saturation current of the discharge measured by a double probe is about 0.2 mA/mm2 at the peak of the pulse.

  20. Shunting arc plasma source for pure carbon ion beam

    Koguchi, H.; Sakakita, H.; Kiyama, S.; Shimada, T.; Sato, Y.; Hirano, Y. [Energy Technology Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), 1-1-1 Umezono, Tsukuba, Ibaraki 305-8568 (Japan)

    2012-02-15

    A plasma source is developed using a coaxial shunting arc plasma gun to extract a pure carbon ion beam. The pure carbon ion beam is a new type of deposition system for diamond and other carbon materials. Our plasma device generates pure carbon plasma from solid-state carbon material without using a hydrocarbon gas such as methane gas, and the plasma does not contain any hydrogen. The ion saturation current of the discharge measured by a double probe is about 0.2 mA/mm{sup 2} at the peak of the pulse.

  1. Shunting arc plasma source for pure carbon ion beam.

    Koguchi, H; Sakakita, H; Kiyama, S; Shimada, T; Sato, Y; Hirano, Y

    2012-02-01

    A plasma source is developed using a coaxial shunting arc plasma gun to extract a pure carbon ion beam. The pure carbon ion beam is a new type of deposition system for diamond and other carbon materials. Our plasma device generates pure carbon plasma from solid-state carbon material without using a hydrocarbon gas such as methane gas, and the plasma does not contain any hydrogen. The ion saturation current of the discharge measured by a double probe is about 0.2 mA∕mm(2) at the peak of the pulse. PMID:22380206

  2. Red cell hexose monophosphate shunt activity measurement for rapid determination of severity of G6PD deficiency

    Persons having an inborn deficiency of erythrocytic glucose-6-phosphate dehydrogenase (G6PD) may be resistent to malaria infection and susceptible to acute intravascular hemolysis following administration of a therapeutic regimen of one of several known hemolytic antimalarial agents. Measurement of red cell hexose monophosphate shunt (HMS) activity provides a direct measure of G6PD activity because this enzyme limits overall HMS activity. In the erythrocyte, respiration is achieved through glycolysis, and therefore CO2 release from these cells may be attributed to glucose passage through the HMS. Incubation of intact red cells in the presence of D(1-14C) glucose with subsequent recovery and quantitation of 14CO2 provides a direct measure of HMS activity. The procedure described in this report provides a measure of relative G6PD activity which may putatively identify a G6PD deficient individual while at the same time providing a reliable estimate of the severity of G6PD deficiency

  3. Shunt currents in vanadium flow batteries: Measurement, modelling and implications for efficiency

    Fink, H.; Remy, M.

    2015-06-01

    Shunt currents are an important factor which must be considered when designing a stack for flow batteries. They lead to a reduction of the coulombic efficiency and can cause furthermore a critical warming of the electrolyte. Shunt currents inevitably appear at bypass connections of the hydraulic system between the single cells of a stack. In this work the shunt currents of a five-celled mini stack of a vanadium flow battery with external hydraulic system and their effects are investigated directly. The external hydraulic system allows the implementation of current sensors for direct measurement of the shunt currents; moreover, the single bypass channels can be interrupted by clamping the tube couplings and with it the shunt currents between the cells when the pumps are off. Thus the shares of losses by cross contamination and by shunt currents are quantified separately by charge conservation measurements. The experimentally gained data are compared to a shunt current model based on a equivalent circuit diagram and the linear equation system derived from it. Experiments and model data are in good agreement. The effects of shunt currents for different flow frame geometries and number of cells in a stack are simulated and presented in this work.

  4. Effects of Ventriculoperitoneal Shunt on the Neutrophil Chemotaxis and NBT in Hydrocephalic Children

    F Nejat

    2005-11-01

    Full Text Available Background: Hydrocephalus is a hydrodynamic disturbance of cerebrospinal fluid (CSF that increases the intracranial volume of CSF. Ventriculo-peritoneal shunt, that diverts CSF from the ventricle, is the most common treatment for hydrocephalus. Infection is the most common complication of ventriculo-peritoneal shunt. The role of immune system in shunt infection has been studied before. We did this study to evaluate the effect of shunt catheter on nitro blue tetrazolium (NBT assay and neutrophil chemotaxis. Methods: In this experimental, a before after study was conducted on 24 hydrocephalic children who had underwent ventriculo-peritoneal shunt operation in Children’s Medical Center. Neutrophil count, chemotaxis and NBT were studied before operation and 2 months thereafter. Findings: There was no statistically significant difference in neutrophil count, chemotaxis and NBT in patients before and after shunt operation. The age of patients at the time of surgery, etiology and duration of hydrocephalus, before operation and shunt infection did not have any significant effect on these tests. Conclusion: Ventriculo-peritoneal shunt catheter could not induce systemic effect on neutrophil count, chemotaxis and NBT.

  5. Evaluation of LeVeen-shunt patency using Tc-99m labelled macroaggregated albumin.

    Adil, Allah Rakha; Waqar, Amin

    2005-12-01

    A LeVeen peritoneo-venous shunt is placed for intractable ascites. Determination of obstruction site in the shunt tube is a difficult problem. We describe a simple nuclear medicine method using 111MBq (3mCi) of Technetium-99m labeled macro-aggregated albumin injected intraperitoneally. PMID:16398982

  6. Quantitative Evaluation of Arteriovenous Shunts of the Brain Under Clinical and Experimental Conditions

    With the help of a new quantitative method to evaluate shunt function, quantitative evaluations of arteriovenous shunt were carried out on patients with traumatic shunts between the internal carotid artery and the cavernous sinus and with arteriovenous haemangiomata. These indicated that, in traumatic arteriovenous fistulas, up to 90% of the blood from the internal carotid is shunted into the cavernous sinus. In patients with arteriovenous haemangiomata shunt flow ranged from 30 to 7%. Post-operatively, both the cerebral blood flow (measured by 133Xe) and the shunt flow showed a return to normal. Shunt function was also evaluated in 28 test animals, their cerebral blood flow having previously been studied, using 133Xe. Six cats formed a control group, the remaining 22 being divided into two groups of 11 animals each. Respiratory acidosis was induced in one group and respiratory alkalosis in the other. The results revealed that the shunt flow was reduced in acidosis (mean 18.26%) and increased in alkalosis (mean 50.1%). In normal animals it averaged 29.4%. (author)

  7. Electroacoustic absorbers: bridging the gap between shunt loudspeakers and active sound absorption.

    Lissek, Hervé; Boulandet, Romain; Fleury, Romain

    2011-05-01

    The acoustic impedance at the diaphragm of an electroacoustic transducer can be varied using a range of basic electrical control strategies, amongst which are electrical shunt circuits. These passive shunt techniques are compared to active acoustic feedback techniques for controlling the acoustic impedance of an electroacoustic transducer. The formulation of feedback-based acoustic impedance control reveals formal analogies with shunt strategies, and highlights an original method for synthesizing electric networks ("shunts") with positive or negative components, bridging the gap between passive and active acoustic impedance control. This paper describes the theory unifying all these passive and active acoustic impedance control strategies, introducing the concept of electroacoustic absorbers. The equivalence between shunts and active control is first formalized through the introduction of a one-degree-of-freedom acoustic resonator accounting for both electric shunts and acoustic feedbacks. Conversely, electric networks mimicking the performances of active feedback techniques are introduced, identifying shunts with active impedance control. Simulated acoustic performances are presented, with an emphasis on formal analogies between the different control techniques. Examples of electric shunts are proposed for active sound absorption. Experimental assessments are then presented, and the paper concludes with a general discussion on the concept and potential improvements. PMID:21568400

  8. 21 CFR 882.5550 - Central nervous system fluid shunt and components.

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Central nervous system fluid shunt and components... Central nervous system fluid shunt and components. (a) Identification. A central nervous system fluid... central nervous system to an internal delivery site or an external receptacle for the purpose of...

  9. Cabinet Sh2104 with protective equipment for shunting reactors

    Mogilev, G.P.; Kozina, N.I.; Ivanova, N.M.; Berger, P.A.

    1985-08-01

    A cabinet with a set of protective equipment for shunting reactors has been developed by the All-Union Scientific Research Institute of Relay Engineering. This Sh2104 cabinet houses relays for protection and control of compensating reactors as well. The equipment will protect a reactor whether the latter is connected into the line directly or through a tripping switch, by disconnecting it from the line or by actuating that switch respectively. For better reliability, the equipment for protection of shunting relays is grouped into a main set and a backup set. The main set includes longitudinally-acting differential phase-current relays, lead high-voltage insulation checkers, gas-leak protection, and standby reactor or line disconnectors. The backup set includes a 2-step zero-sequence current relay. The equipment for protection of compensating reactors consists of longitudinally acting differential current relays, distance relays, peak-current relays, and gas-leak protection. Two power supplies (50 W and 100 W) are provided for energizing all the equipment in this cabinet. Provided are also means for continuous operational monitoring and spot-check testing. The overall dimensions are 600x600x2200 mm/sup 3/, the total weight is 250 kg.

  10. DSA diagnosis of nontumorous arterioportal shunt in cirrhosis

    Objective: To assess the diagnostic value of DSA for nontumorous arterioportal shunt in cirrhosis. Methods: One hundred seventy cirrhotic patients without HCC under going transhepatic artery self bone marrow stem cell transplantation were taken liver arterial DSA together with 165 CT data. Arterioportal shunt (APS) appearance phase, persisting time and characteristics of liver parenchyma staining caused by APS were analyzed dynamically. Small HCC was differentiated from nontumorous APS. TACE procedure was done when HCC lesion was confirmed by DSA findings. Results: 31.7%(54/170) DSA presented the sign of APS. Among the 142 case with no evidence of APS on CT examinations, but APS was seen in DSA of 31 cases (21.8%). All patients with CT findings of liver abnormal enhancement of APS, 23 cases including 16 cases as nontermorous and 7 cases whose CT arterial phase showing local persistant enhancement without declination in portal venous phase which was recognized to be HCC later by DSA characteristics with only one having tumorous APS. Conclusions: DSA has a comparative high visualization rate of nontumorous APS in liver cirrhosis and benefits the differentiation with malignant lesions guiding the interventional procedure. (authors)

  11. Fabrication and characterization of shunted μ-SQUID

    In order to eliminate hysteresis, we have fabricated and characterized niobium based shunted micron size superconducting quantum interference devices (μ-SQUIDs). We find a wide temperature range where these μ-SQUIDs are non-hysteretic in nature and show a very good Ic vs. B oscillations in hysteretic regime and V vs. B oscillations in non-hysteretic regime. Here we report the characteristics of a shunted- μ-SQUID (Wf38LS72D5). In this device we have achieved a large voltage modulation, in non-hysteretic regime, at various temperatures including such as 1.1 mV at 6.62 K with a transfer function VΦ = 7.2mV/Φ0. The figures within the original article PDF file, as supplied to AIP Publishing, were affected by a PDF-processing error. Consequently, the article re-flowed and pagination increased from 3 to 4 pages. This article was updated on 14 May 2014 to correct the PDF-processing error, with the scientific content remaining unchanged. Readers are advised that the replacement article PDF file contains an additional blank page to preserve the original pagination

  12. Ventriculoperitoneal shunt-related infections caused by Staphylococcus epidermidis: pathogenesis and implications for treatment.

    Stevens, Niall T

    2012-12-01

    The insertion of medical devices, such as intraventricular shunts, is often complicated by infection leading to ventriculitis. Frequently, such infections result from colonisation and subsequent biofilm formation on the surfaces of the shunts by Staphylococcus epidermidis. The pathogenesis of neurosurgical shunt-related infection is complex with interactions between the pathogen, the device and the unique local immunological environment of the central nervous system (CNS). An ability to form biofilm, the main virulence determinant of Staphylococcus epidermidis, facilitates protection of the organism from the host defences while still initiating an immunological response. The presence of the blood brain barrier (BBB) and the biofilm itself also complicates treatment, which presents many challenges when managing shunt infections. A greater understanding of the interplay between S. epidermidis and the CNS could potentially improve the diagnosis, treatment and management of such infections. This review describes the pathogenesis, treatment and implications of S. epidermidis ventriculoperitoneal shunt-related infections, concentrating on recent research and the implications for treatment.

  13. Tunable band gaps in acoustic metamaterials with periodic arrays of resonant shunted piezos

    Chen Sheng-Bing; Wen Ji-Hong; Wang Gang; Wen Xi-Sen

    2013-01-01

    Periodic arrays of resonant shunted piezoelectric patches are employed to control the wave propagation in a twodimensional (2D) acoustic metamaterial.The performance is characterized by the finite element method.More importantly,we propose an approach to solving the conventional issue of the nonlinear eigenvalue problem,and give a convenient solution to the dispersion properties of 2D metamaterials with periodic arrays of resonant shunts in this article.Based on this modeling method,the dispersion relations of a 2D metamaterial with periodic arrays of resonant shunted piezos are calculated.The results show that the internal resonances of the shunting system split the dispersion curves,thereby forming a locally resonant band gap.However,unlike the conventional locally resonant gap,the vibrations in this locally resonant gap are unable to be completely localized in oscillators consisting of shunting inductors and piezo-patches.

  14. A rare cause of pediatric urinary incontinence: Ventriculoperitoneal shunt with bladder perforation

    Manuel C See IV

    2016-04-01

    Full Text Available We present a case of 2-year-old boy with long term dysuria and intermittent incontinence, and new onset of fever and headache. Significant past medical history includes congenital hydrocephalus with a ventriculoperitoneal shunt placement two years prior to consult. On physical examination, a tubular structure was noted underneath the prepuce suspected to be the distal tip of ventriculoperitoneal shunt, which was confirmed by kidney, ureter and bladder (KUB X-ray and CT scan. Patient was treated with a novel approach of extraperitoneal removal of ventriculoperitoneal shunt distal tip with cystorrhaphy via a low transverse pfannenstiel incision, separate left ventriculostomy tube insertion and complete removal of ventriculoperitoneal shunt from the right ventricle. This report accounts a rare pediatric case with ventriculoperitoneal shunt perforation into a normal bladder successfully treated with mini-open surgery.

  15. Indigenous cost-effective peritoneo-venous shunt for refractory ascites.

    Marimuthu, K; Kumar, A Suresh; Sabanathan, S; Gowrishankar, A; Kumar, P Sasi; Rajkumar, J S

    2004-01-01

    About 5% of patients with chronic liver disease develop massive refractory ascites. These patients cease to respond to diuretic therapy and may develop prerenal azotemia. There is a small but definite role for the peritoneo-venous shunt in these patients. In our study of 36 patients, managed with locally made, single-valved peritoneo-venous shunts (GSAIMS shunts), shunt failure and complication rates were assessed postoperatively. There is a definite improvement in quality of life with this cost-effective locally made shunt if patients are selected carefully. Long-term follow-up of these patients is not possible because most of these patients succumb to advanced liver disease. PMID:15285240

  16. Quantitative determination of peripheral arterio-venous shunts by means of radioactively labelled microspheres

    In the present work a nuclear method of quantitative measurement of peripheral arterio-venous shunts with a whole-body scanner is standardized. This method, developed at the beginning of the 70s at Tuebingen, stands out in contrast with earlier measuring methods by the application of the theory of quantitative scintiscanning. This means that the scintigram obtained after injection of sup(99m)technetium-labelled human albumin microspheres into an artery before the shunt is corrected for the quantitative shunt calculation by several factors using a computer, to avoid systematic mistakes. For the standardization of the method, 182 scintigrams were taken during model experiments and experiments on animals and human beings. This method, having a deviation of 10% at most, is excellently suited for the quantitative determination of peripheral arterio-venous shunts. Already for a pulmonary activity of 3% a peripheral shunt is proved with 97.5% probability. (orig./MG)

  17. Tunable band gaps in acoustic metamaterials with periodic arrays of resonant shunted piezos

    Periodic arrays of resonant shunted piezoelectric patches are employed to control the wave propagation in a two-dimensional (2D) acoustic metamaterial. The performance is characterized by the finite element method. More importantly, we propose an approach to solving the conventional issue of the nonlinear eigenvalue problem, and give a convenient solution to the dispersion properties of 2D metamaterials with periodic arrays of resonant shunts in this article. Based on this modeling method, the dispersion relations of a 2D metamaterial with periodic arrays of resonant shunted piezos are calculated. The results show that the internal resonances of the shunting system split the dispersion curves, thereby forming a locally resonant band gap. However, unlike the conventional locally resonant gap, the vibrations in this locally resonant gap are unable to be completely localized in oscillators consisting of shunting inductors and piezo-patches

  18. Early mediastinal seroma secondary to modified Blalock-Taussig shunts - successful management by percutaneous drainage

    Connolly, Bairbre L.; Temple, Michael J.; Chait, Peter G.; Restrepo, Ricardo [Department of Diagnostic Imaging, Hospital for Sick Children, University of Toronto, 555 University Avenue, Toronto, Ontario M5G 1X8 (Canada); Adatia, Ian [Department of Cardiology and Critical Care Medicine, The Hospital for Sick Children, University of Toronto, 555 University Avenue, Toronto, Ontario M5G 1X8 (Canada)

    2003-07-01

    Large symptomatic mediastinal seroma following modified-BT shunts, traditionally required revisional thoracotomy. We describe percutaneous image-guided pigtail catheter drainage in the successful treatment of early mediastinal seroma secondary to PTFE Blalock-Taussig shunt, avoiding thoracotomy. A retrospective review of all relevant clinical and imaging records in five patients was performed. All five presented with intermittent stridor, respiratory distress and/or episodic desaturation within 6 weeks of their surgery. In four of five infants, percutaneous drainage was effective and reoperation was avoided. In one of five, rather than urgent surgical evacuation and BT shunt revision, we were able to perform an elective stage-II bidirectional Glenn SVC-RA anastamosis in a stable infant. There were no complications. Percutaneous image-guided drainage of mediastinal seroma secondary to PTFE-BT shunt is a safe, minimally invasive, and effective treatment. This may avoid BT shunt revision. (orig.)

  19. Clinical and ultrasonographic criteria for using ventriculoperitoneal shunts in newborns with myelomeningocele

    Jose Roberto Tude Melo

    2015-09-01

    Full Text Available Objective Hydrocephalus is one of the main complications associated with myelomeningocele (MM. This study aimed to identify clinical and ultrasonographic criteria for using ventriculoperitoneal (VP shunts in this group of patients.Method A retrospective cohort study, based on established protocol for VP shunt implant in hydrocephalic children with MM. Parameters used to guide the indication of VP shunts included measurement of head circumference (HC, evaluation of fontanels, and measurement of lateral ventricular atrium (LVA width by transcranial ultrasonography.Results 43 children were included in the analysis, of which 74% had hydrocephalus and required a VP shunt. These children had LVA width ≥ 15 mm, showed increased HC, or had bulging fontanels.Conclusion VP shunt is required in children with increased HC (≥ 2 standard deviation regarding age group, bulging fontanels, or LVA width of ≥ 15 mm after the closure of MM.

  20. Early mediastinal seroma secondary to modified Blalock-Taussig shunts - successful management by percutaneous drainage

    Large symptomatic mediastinal seroma following modified-BT shunts, traditionally required revisional thoracotomy. We describe percutaneous image-guided pigtail catheter drainage in the successful treatment of early mediastinal seroma secondary to PTFE Blalock-Taussig shunt, avoiding thoracotomy. A retrospective review of all relevant clinical and imaging records in five patients was performed. All five presented with intermittent stridor, respiratory distress and/or episodic desaturation within 6 weeks of their surgery. In four of five infants, percutaneous drainage was effective and reoperation was avoided. In one of five, rather than urgent surgical evacuation and BT shunt revision, we were able to perform an elective stage-II bidirectional Glenn SVC-RA anastamosis in a stable infant. There were no complications. Percutaneous image-guided drainage of mediastinal seroma secondary to PTFE-BT shunt is a safe, minimally invasive, and effective treatment. This may avoid BT shunt revision. (orig.)

  1. Communicating hydrocephalus due to cerebral venous sinus thrombosis treated with ventriculoperitoneal shunt

    Rahul T Chakor

    2012-01-01

    Full Text Available Cerebral venous sinus thrombosis (CVT is a rare cerebrovascular disease with variable presentation. CVT rarely causes hydrocephalus. Communicating hydrocephalus due to CVT is extremely rare. We describe a patient of CVT presenting with chronic headache and communicating hydrocephalus. The patient was successfully treated with ventriculoperitoneal (VP shunt. A 40 year old man presented with moderate to severe headache since six months and progressive visual loss since two months. Head Computed tomogram showed mild hydrocephalus without obstruction. Lumbar puncture (LP demonstrated elevated pressure but was otherwise normal. Magnetic resonance venogram showed extensive CVT. Repeated CSF drainage and thecoperitoneal shunt did not relieve the severe headache hence a VP shunt was placed. Post shunt headache subsided with resolution of hydrocephalus. CVT can present as communicating hydrocephalus. Gradual reduction of intra-ventricular pressure by repeated LPs followed by VP shunt can safely treat hydrocephalus due to CVT.

  2. Immunopathology of giardiasis: the role of lymphocytes in intestinal epithelial injury and malfunction

    AG Buret

    2005-03-01

    Full Text Available T lymphocyte-mediated pathogenesis is common to a variety of enteropathies, including giardiasis, cryptosporidiosis, bacterial enteritis, celiac's disease, food anaphylaxis, and Crohn's disease. In giardiasis as well as in these other disorders, a diffuse loss of microvillous brush border, combined or not with villus atrophy, is responsible for disaccharidase insufficiencies and malabsorption of electrolytes, nutrients, and water, which ultimately cause diarrheal symptoms. Other mucosal changes may include crypt hyperplasia and increased infiltration of intra-epithelial lymphocytes. Recent studies using models of giardiasis have shed new light on the immune regulation of these abnormalities. Indeed, experiments using an athymic mouse model of infection have found that these epithelial injuries were T cell-dependent. Findings from further research indicate that that the loss of brush border surface area, reduced disaccharidase activities, and increase crypt-villus ratios are mediated by CD8+ T cells, whereas both CD8+ and CD4+ small mesenteric lymph node T cells regulate the influx of intra-epithelial lymphocytes. Future investigations need to characterize the CD8+ T cell signaling cascades that ultimately lead to epithelial injury and malfunction in giardiasis and other malabsorptive disorders of the intestine.

  3. Influence of malfunctions of the maintenance activities on the urban buses fuel consumption

    George, Crişan; Nicolae, Filip

    2014-06-01

    Optimization of activities with the aim to provide quality service in conditions of high profitability, is one of the main objectives chased by managers in transportation companies. As a consequence, directing the attention towards monitoring of maintenance activities of vehicles fleet, can achieve desired results. Two of the most important issues related to the maintenance activity, is the increase of reliability and reduction of fuel consumption of the vehicles fleet. Aforementioned actions represents a way forward for raising the quality and profitability of services offered. In this paper, the main ways of monitoring the fuel consumption, in order to reduce it and increase the reliability of transportation vehicles fleet, are presented. For the evaluation of the maintenance system and the degree of influence of malfunctions recorded on the fuel consumption, using the Pareto -ABC method, following case study on a fleet of buses for urban public transport has been conducted. Results obtained highlights the deficiencies of the maintenance process carried out and constitutes a solid base for the reorganization of the maintenance activity, involving preventive maintenance activities, in order to contribute decisively to the results targeted by the management of transport companies.

  4. Uncovering the link between malfunctions in Drosophila neuroblast asymmetric cell division and tumorigenesis

    Kelsom Corey

    2012-11-01

    Full Text Available Abstract Asymmetric cell division is a developmental process utilized by several organisms. On the most basic level, an asymmetric division produces two daughter cells, each possessing a different identity or fate. Drosophila melanogaster progenitor cells, referred to as neuroblasts, undergo asymmetric division to produce a daughter neuroblast and another cell known as a ganglion mother cell (GMC. There are several features of asymmetric division in Drosophila that make it a very complex process, and these aspects will be discussed at length. The cell fate determinants that play a role in specifying daughter cell fate, as well as the mechanisms behind setting up cortical polarity within neuroblasts, have proved to be essential to ensuring that neurogenesis occurs properly. The role that mitotic spindle orientation plays in coordinating asymmetric division, as well as how cell cycle regulators influence asymmetric division machinery, will also be addressed. Most significantly, malfunctions during asymmetric cell division have shown to be causally linked with neoplastic growth and tumor formation. Therefore, it is imperative that the developmental repercussions as a result of asymmetric cell division gone awry be understood.

  5. Ares-I-X Vehicle Preliminary Range Safety Malfunction Turn Analysis

    Beaty, James R.; Starr, Brett R.; Gowan, John W., Jr.

    2008-01-01

    Ares-I-X is the designation given to the flight test version of the Ares-I rocket (also known as the Crew Launch Vehicle - CLV) being developed by NASA. As part of the preliminary flight plan approval process for the test vehicle, a range safety malfunction turn analysis was performed to support the launch area risk assessment and vehicle destruct criteria development processes. Several vehicle failure scenarios were identified which could cause the vehicle trajectory to deviate from its normal flight path, and the effects of these failures were evaluated with an Ares-I-X 6 degrees-of-freedom (6-DOF) digital simulation, using the Program to Optimize Simulated Trajectories Version 2 (POST2) simulation framework. The Ares-I-X simulation analysis provides output files containing vehicle state information, which are used by other risk assessment and vehicle debris trajectory simulation tools to determine the risk to personnel and facilities in the vicinity of the launch area at Kennedy Space Center (KSC), and to develop the vehicle destruct criteria used by the flight test range safety officer. The simulation analysis approach used for this study is described, including descriptions of the failure modes which were considered and the underlying assumptions and ground rules of the study, and preliminary results are presented, determined by analysis of the trajectory deviation of the failure cases, compared with the expected vehicle trajectory.

  6. Implementing an Expert Diagnostic Assistance System for Car Failure and Malfunction

    Salama A. Mostafa

    2012-03-01

    Full Text Available Applications in fault diagnosis are continuously being implemented to serve different sectors. Car failure detection is a sequence of diagnostic processes that necessitates the deployment of expertise. The Expert System (ES is one of the leading Artificial Intelligence (AI techniques that have been adopted to handle such task. This paper presents the imperatives for an ES in developing car failure detection model and the requirements of constructing successful Knowledge-Based Systems (KBS for such model. In addition, it exhibits the adaptation of the ES in the development of Car Failure and Malfunction Diagnosis Assistance System (CFMDAS. However, CFMDAS development faces many challenges such as collecting the required data for building the knowledge base and performing the inferencing. Furthermore, diagnosis of car faults requires high technical skills and experienced mechanics who are typically scarce and expensive to get. Thus, systems such as CFMDAS can be highly useful in assisting mechanics for failure detection and training purposes. Moreover, capturing and retaining valuable knowledge on such domain yield more accurate and less time consuming models.

  7. Feasibility of conductance catheter-derived pressure–volume loops to investigate ventricular mechanics in shunted single ventricles

    Butts, Ryan J.; Hsia, Tain-Yen; Baker, G. Hamilton

    2013-01-01

    We present pressure–volume loops obtained from two patients with single-ventricle physiology, one with a modified Blalock–Taussig shunt and one with a right ventricle-to-pulmonary artery shunt. The dissimilarities in pressure–volume loop contour and related indices highlight potentially important differences in ventricular mechanics between the shunt types.

  8. Comparison of outcomes between patients with idiopathic normal pressure hydrocephalus who received a primary versus a salvage shunt.

    Moran, Dane; Hung, Alice; Vakili, Sharif; Fialho, Hugo; Jeon, Lee; Sankey, Eric W; Jusué-Torres, Ignacio; Lu, Jennifer; Goodwin, C Rory; Elder, Benjamin D; Rigamonti, Daniele

    2016-07-01

    Placement of a ventriculoperitoneal (VP) shunt is the treatment of choice for communicating hydrocephalus; however, the extent to which VP shunting is able to relieve symptoms in patients who had previously been treated with cerebrospinal fluid diverting therapy at an outside institution remains unclear. A retrospective review of patients with idiopathic normal pressure hydrocephalus treated with VP shunts at a single institution between 1993 and 2013 was conducted. Patients were classified as having received a primary VP shunt if they had not been previously treated with a VP shunt, ventriculoatrial shunt, lumboperitoneal shunt, or endoscopic third ventriculostomy. Patients were classified as having received a salvage VP shunt if they had been previously treated by one of these four modalities at an outside institution prior to their presentation to our institution. There were 357 patients who received a primary shunt and 33 patients who received a salvage shunt. Patients who had a salvage shunt placed had significantly higher odds of requiring a future revision (54% versus 41%; odds ratio=2.85; 95% confidence interval [CI]: 1.24-6.57; p=0.014). Patients who received a salvage shunt had statistically significantly lower rates of gait improvement at 6months in comparison to patients who received a primary shunt (relative risk=0.35; 95% CI: 0.14-0.87; p=0.025). Despite these findings, there was no significant difference at last follow-up in improvement in gait, continence, and cognition, indicating that outcomes for patients requiring a salvage shunt were comparable to patients receiving a primary shunt. PMID:26898583

  9. Different Degree in Proteasome Malfunction Has Various Effects on Root Growth Possibly through Preventing Cell Division and Promoting Autophagic Vacuolization

    Xianyong Sheng; Qian Wei; Liping Jiang; Xue Li; Yuan Gao; Li Wang

    2012-01-01

    The ubiquitin/proteasome pathway plays a vital role in plant development. But the effects of proteasome malfunction on root growth, and the mechanism underlying this involvement remains unclear. In the present study, the effects of proteasome inhibitors on Arabidopsis root growth were studied through the analysis of the root length, and meristem size and cell length in maturation zone using FM4-64, and cell-division potential using GFP fusion cyclin B, and accumulation of ubiquitinated protei...

  10. The structure of an expert system to diagnose and supply a corrective procedure for nuclear power plant malfunctions

    During the past two years, two prototype knowledge based systems have been developed at the Ohio State University. These systems were the result of collaboration between the Nuclear Engineering Program and the Laboratory for Artificial Intelligence Research (LAIR). The first system uses hierarchical classification to diagnose malfunctions of the coolant system in a General Electric Boiling Water Reactor (BWR). The second system provides a plan of action, through a process of dynamic procedure management, to stabilize the plant once an abnormal transient has occurred. The objective of this paper is to discuss the structure that has been designed to integrate the two systems. The combined system will be capable of informing plant personnel about the nature of malfunctions, and of supplying to the operator the most direct corrective procedure available. Two important features of the integrated system are faulty sensor detection, based on malfunction context and unlike sensor data, and procedure management based on the initial state of the plant. Since the two knowledge based systems were developed separately, the integration has required a separate component currently under development, the Plant Status Monitoring System (PSMS). The task of PSMS is to monitor plant parameters in order to detect an abnormal condition developing within the plant. Based on the nature of the event, PSMS is capable of directing control to either the procedure management or diagnosis component. The integrated system plays only an advisory role, and any suggested action would be executed by the plant personnel

  11. Scintigraphic evaluation of hepatic blood flow after intrahepatic portosystemic shunt (TIPS).

    Menzel, J; Schober, O; Reimer, P; Domschke, W

    1997-06-01

    In patients with liver cirrhosis a transjugularly placed intrahepatic portocaval shunt (TIPS) is a non-surgical portosystemic device which aims to reduce portal venous pressure. In comparison with Doppler sonography, we evaluated in 28 patients the diagnostic impact of liver perfusion scintigraphy (with technetium-99m diethylene triamine penta-acetic acid) in the assessment of changes in the hepatic blood flow after TIPS shunting. The arterial and portal contributions to hepatic flow were calculated from the areas under the biphasic time-activity curve. In the course of TIPS shunting, patency is threatened by reocclusion. Angiography is the gold standard for TIPS shunt reassessment. However, there is a need for a less invasive diagnostic procedure, such as scintigraphy or Doppler sonography, for the early detection of shunt insufficiency. Scintigraphy demonstrated that prior to TIPS shunting the portal venous contribution to hepatic perfusion was reduced to 29.2%, this reduction being due to portal hypertension. After TIPS placement a significant increase in portal venous perfusion was observed (38.2%; Pscintigraphically measured portal venous contribution to hepatic blood flow. Hepatic perfusion scintigraphy appears to be a valuable method to determine the immediate effect of TIPS on hepatic blood flow. Post-TIPS follow-up studies of hepatic haemodynamics by liver perfusion scintigraphy appear able to contribute to the detection of TIPS shunt occlusion before the clinical consequences of this complication have become apparent. PMID:9169570

  12. Numerical and experimental studies of stack shunt current for vanadium redox flow battery

    Highlights: • A coupled three-dimensional model of VRB cell stack is developed. • Shunt current of the stack is studied with the model and experiment. • Increased electrolyte resistance in channel and manifold lowers the shunt current. • Shunt current loss increases with stack cell number nonlinearly. - Abstract: The stack shunt current of VRB (vanadium redox flow battery) was investigated with experiments and 3D (three-dimensional) simulations. In the proposed model, cell voltages and electrolyte conductivities were calculated based on electrochemical reaction distributions and SOC (state of charge) values, respectively, while coulombic loss was estimated according to shunt current and vanadium ionic crossover through membrane. Shunt current distributions and coulombic efficiency are analyzed in terms of electrolyte conductivities and stack cell numbers. The distributions of cell voltages and shunt currents calculated with proposed model are validated with single cell and short stack tests. The model can be used to optimize VRB stack manifold and channel designs to improve VRB system efficiency

  13. Controversies: Optic nerve sheath fenestration versus shunt placement for the treatment of idiopathic intracranial hypertension

    Arielle Spitze

    2014-01-01

    Full Text Available Background: Idiopathic intracranial hypertension (IIH has been increasing in prevalence in the past decade, following the obesity epidemic. When medical treatment fails, surgical treatment options must be considered. However, controversy remains as to which surgical procedure is the preferred surgical option - optic nerve sheath fenestration (ONSF or cerebrospinal fluid (CSF shunting - for the long-term treatment of this syndrome. Purpose: To provide a clinical update of the pros and cons of ONSF versus shunt placement for the treatment of IIH. Design: This was a retrospective review of the current literature in the English language indexed in PubMed. Methods: The authors conducted a PubMed search using the following terms: Idiopathic IIH, pseudotumor cerebri, ONSF, CSF shunts, vetriculo-peritoneal shunting, and lumbo-peritoneal shunting. The authors included pertinent and significant original articles, review articles, and case reports, which revealed the new aspects and updates in these topics. Results: The treatment of IIH remains controversial and lacks randomized controlled clinical trial data. Treatment of IIH rests with the determination of the severity of IIH-related visual loss and headache. Conclusion: The decision for ONSF versus shunting is somewhat institution and surgeon dependent. ONSF is preferred for patients with visual symptoms whereas shunting is reserved for patients with headache. There are positive and negative aspects of both procedures, and a prospective, randomized, controlled trial is needed (currently underway. This article will hopefully be helpful in allowing the reader to make a more informed decision until that time.

  14. Localization of left-to-right shunts by radionuclide angiocardiography (RAC)

    A method to detect, quantify and localize left-to-right shunts by computer analysis of radionuclide angiocardiography has been developed. Thirty-eight patients were studied, 28 with left-to-right shunts and 10 without any evidence of cardiovascular disease. Twelve cases of ventricular septal defect were localized accurately, three pre-operatively and nine post-operatively with residual left-to-right shunt. Eight patients had shunts localized at the atrial level and confirmed by cardiac catheterization and surgery. In one patient valvular pulmonic stenosis was confirmed by absence of any left-to-right shunt whatsoever. Three patients appeared to have sufficiently specific streaming of the left-to-right shunt that the shunt was localized at the next downstream level. A patient in whom we diagnosed ASD went to surgery directly without the need for cardiac catheterization. Multiple studies can be done pre-operatively and post-operatively, for diagnostic purposes, or to follow the patient's progress. (author)

  15. Arterio-venous shunts or low oxygen utilization?

    Rozin, Alexander P

    2010-02-01

    An idea of arteriovenous shunts (AVS) was proposed for explanation of dynamic regulation of oxygenation and venous hyperoxia. A formula enabling calculation of AVS and real CO2 production has recently been derived by comparing data of arterial and venous blood gases. Regarding venous hyperoxia, there is a need to differentiate capillary to tissue transport defect (low oxygen utilisation-LOU) from AVS, which may exist simultaneously. The AVS may be associated with normal or relatively high oxygen utilization from the capillary vessels and increased CO2 production. AVS is proposed to carry protective and 'stealing' properties including renal, cardiac, and pulmonary hemodynamic. Calculations of the AVS may be important for dynamic assessment of vascular and metabolic status and in emergency medicine. PMID:20026514

  16. Surgical treatment of hepatocellular carcinoma with severe intratumoral arterioportal shunt

    Hiromichi Ishii, Teruhisa Sonoyama, Shingo Nakashima, Hiroyuki Nagata, Atsushi Shiozaki, Yoshiaki Kuriu, Hisashi Ikoma, Masayoshi Nakanishi, Daisuke Ichikawa, Hitoshi Fujiwara, Kazuma Okamoto, Toshiya Ochiai, Yukihito Kokuba, Chohei Sakakura, Eigo Otsuji

    2010-07-01

    Full Text Available We report a case of hepatocellular carcinoma (HCC that caused a severe arterioportal shunt (APS. A 49-year-old man was admitted to hospital due to esophagogastric variceal hemorrhage and HCC, and underwent endoscopic variceal ligation (EVL and endoscopic injection sclerotherapy (EIS. He was then referred to our hospital. Abdominal computed tomography revealed a low-density lesion in the posterior segment of the liver and an intratumoral APS, which caused portal hypertension. Although the patient underwent EVL, EIS, Hassab’s operation, and transcatheter arterial embolization for APS, he vomited blood due to rupture of esophagogastric varices. Right hepatectomy was performed for the treatment of HCC and APS, although the indocyanine green retention value at 15 min after intravenous injection was poor (30%. The patient’s postoperative course was uneventful. Eventually, APS disappeared and the esophagogastric varices improved.

  17. Shunt diode designs in Li/CF Shuttle batteries

    Miller, D.; Higgins, R.

    1984-09-01

    Although Li/CF cells and batteries have an excellent safety record, they are included with other battery systems that require additional safety precautions. One precaution suggested is the inclusion of shunt diodes into these batteries. The benefits of this addition are examined. All cells tested at elevated temperatures vent regardless of length of time between being fully discharged and reversed or inclusion of the diode in the system. Cells discharged at ambient temperatures all show a relatively quick reversal, but stabilize at voltages that are high enough that the diodes are not functioning. Cells tested at depressed temperatures reverse the deepest of all cells tested, with the deepest reversal occurring very early in the test and voltages recovering to above -0.60 volts near the end of the tests. Anode limited cells will eliminate the venting during hot reversal.

  18. A SQUID gradiometer module with large junction shunt resistors

    A dual-washer superconducting quantum interference device (SQUID) with a loop inductance of 350 pH and two on-washer integrated input coils is designed according to conventional niobium technology. In order to obtain a large SQUID flux-to-voltage transfer coefficient, the junction shunt resistance is selected to be 33 Ω. A vertical SQUID gradiometer module with a baseline of 100 mm is constructed by utilizing such a SQUID and a first-order niobium wire-wound antenna. The sensitivity of this module reaches about 0.2 fT/(cm·Hz1/2) in the white noise range using a direct readout scheme, i.e., the SQUID is directly connected to an operational amplifier, in a magnetically shielded room. Some magnetocardiography (MCG) measurements with a sufficiently high signal-to-noise ratio (SNR) are demonstrated. (interdisciplinary physics and related areas of science and technology)

  19. Selective Harmonic Current Mitigation with Shunt Active Power Filter

    Hansen, Steffan; Lascu, Cristian; Asiminoaei, Lucian;

    2007-01-01

    drawbacks, the paper shows that the last two methods have a more compact mathematical representation which may extend to straightforward DSP implementation. However, the first method, i.e. selective compensation in harmonic dq-frame, is more flexible and allows a better tuning and adjustment, which is of a......The paper presents three methods of selective harmonic compensation with shunt Active Power Filters in different reference frames: harmonic dq-frame, stationary frame and fundamental dq-frame; and shows that the last two methods are derived from the first one. By analyzing their advantages and...... great importance in practice. For experimental tests only the selective harmonic control in fundamental dq-frame is presented, to demonstrate the selectiveness harmonic current compensation. The experimental results are performed in laboratory conditions on a 7 kVA Active Filter prototype, indicating a...

  20. Developmental intrahepatic shunts of childhood: radiological features and management

    The purpose of this study was to evaluate the role of radiological techniques in the diagnosis and management of developmental intrahepatic shunts. Hepatic vascular fistulae are recognised sequelae of liver trauma and intrahepatic tumours. However, there are rare developmental malformations which may present in childhood or later life and which may carry life-threatening complications. Retrospective analysis of clinical and radiological data was carried out in 24 patients. Anomalies evaluated were: (a) direct communication between hepatic artery and hepatic veins; (b) congenital hepatoportal arteriovenous malformations; and (c) congenital portocaval anastomosis with persistent flow through the ductus venosus. Although rare, the prompt recognition of these vascular anomalies allows early surgical or radiological intervention and reversal of the haemodynamic complications. (orig.)

  1. Design and Simulation of Microelectromechanical System Capacitive Shunt Switches

    Haslina Jaafar

    2009-01-01

    Full Text Available Problem statement: RF MEMS switch is one of MEMS area that creates devices that have great potential to improve the performance of communication circuits and systems and enables the realization of micro size mechanical switches embedded in electronics devices. The low voltage switches are necessary due to their compatibility of standard IC technology in RF application and microelectronics systems. In realizing MEMS switches with low actuation voltage, spring constant of beam must be reduced. Design and simulation of capacitive RF MEMS shunt switches with regards to the pull in voltage were presented. Approach: Design and simulation had been done by using commercial simulation package, CoventorWare 2006. Several switches were designed with different meander spring beams to obtain lower voltage actuations using Architect Module in CoventorWare 2006. Results: Results verified with Finite Element Method (FEM and simple mathematical modeling. Each design gave different voltage actuations. The lowest actuation voltage simulated was 1.9 V. Average difference of simulated and calculated values was about 16%. This is because no fringing field was included in calculation. Finite Element Method (FEM analysis was done for switch C. Results showed that lower voltage can be obtained by using serpentine spring which lowers the spring constant and pull-in voltage as well. The lower pull-in time was primarily due to its very small dimensions and mass Conclusion: Low-voltage capacitive shunt RF MEMS switches were designed and simulated. These switches had actuation voltages of 1.9-7.0 V depending on the serpentine design. The other performance particularly switch C had a pull-in time of 15 µ sec after a voltage of 0-20 V was applied and the resonant frequency is 3153.1 Hz.

  2. The assessment of the patency of peritoneo-venous shunt with Tc99m-DTPA

    The patency of a LeVeen peritoneo-venous shunt was assessed with a radiopharmaceutical Tcsup(99m)-DTPA, Tcsup(99m)-sulphur colloid was used previously for this purpose Tcsup(99m)-DTPA was given intraperitoneally in three patients with ascites and the blood activity was determined. The radioactivity in the blood was found to be minimal and this was attributed to free pertechnetate. The kidneys and the bladder could not be demonstrated at 45 minutes. This also shows that the minimal activity in the blood was negligible for scintigraphic studies. The valve or the peritoneal tubing of the LeVeen shunt are sometimes occluded with a trombus or clot. So if the proximal part of the tube is demonstrated scintigraphically, it shows that the valve is functioning. But if the distal end of the tubing is occluded, this study will give a false-negative result. It can be claimed that if Tcsup(99m)-sulphur colloid is found in the blood, the shunt will be accepted as patent. The demonstration of the liver in 60 minutes after intraperitoneal injection shows the patency of the shunt precisely. But, demonstration of liver later than 60 min is not an evidence for a patent shunt. As seen with the shunt, after the intraperitoneal injection of Tcsup(99m)-DTPA, the tubing was demonstrated in 5 minutes and the kidneys and bladder in 15 minutes. This finding rules out any distal occlusion of the tubing of the shunt. Another indirect finding to assess the patency of the shunt is the increased background activity after 30 minutes in the chest. The advantages of using Tcsup(99m)-DTPA over Tcsup(99m) sulphur colloid are homogeneous distribution of the radiopharmaceutical in the ascitic fluid more rapid assessment of the patency of the shunt and lower radiation dose to the patient

  3. Gadolinium-enhanced magnetic resonance angiography of right ventricle to pulmonary artery shunts following Norwood 1 palliation in infants

    The classic Norwood I palliation for the treatment of hypoplastic left-heart disease includes an atrial septectomy, neoaorta creation, and a systemic-to-pulmonary artery shunt. The Norwood I palliation has been modified by the use of a right ventricle-to-pulmonary artery shunt instead of a traditional systemic-to-pulmonary artery shunt. Right ventricle-to-pulmonary artery shunts were non-invasively imaged in four infants using gadolinium-enhanced magnetic resonance angiography. Diagnostic MR angiograms were performed in all infants throughout the length of the shunt and were useful in the detection of shunt patency, stenosis, and aneurysm. Associated surgical conduits and shunts were also evaluated. All findings were verified by subsequent conventional angiography or surgery. (orig.)

  4. Are the Current Doppler Echocardiography Criteria Able to Discriminate Mitral Bileaflet Mechanical Heart Valve Malfunction? An In Vitro Study.

    Evin, Morgane; Guivier-Curien, Carine; Pibarot, Philippe; Kadem, Lyes; Rieu, Régis

    2016-05-01

    Malfunction of bileaflet mechanical heart valves in the mitral position could either be due to patient-prosthesis mismatch (PPM) or leaflet obstruction. The aim of this article is to investigate the validity of current echocardiographic criteria used for diagnosis of mitral prosthesis malfunction, namely maximum velocity, mean transvalvular pressure gradient, effective orifice area, and Doppler velocity index. In vitro testing was performed on a double activation left heart duplicator. Both PPM and leaflet obstruction were investigated on a St. Jude Medical Master. PPM was studied by varying the St. Jude prosthesis size (21, 25, and 29 mm) and stroke volume (70 and 90 mL). Prosthesis leaflet obstruction was studied by partially or totally blocking the movement of one valve leaflet. Mitral flow conditions were altered in terms of E/A ratios (0.5, 1.0, and 1.5) to simulate physiologic panel of diastolic function. Maximum velocity, effective orifice area, and Doppler velocity index are shown to be insufficient to distinguish normal from malfunctioning St. Jude prostheses. Doppler velocity index and effective orifice area were 1.3 ± 0.49 and 1.83 ± 0.43 cm(2) for testing conditions with no malfunction below the 2.2 and 2 cm(2) thresholds (1.19 cm(2) for severe PPM and 1.23 cm(2) for fully blocked leaflet). The mean pressure gradient reached 5 mm Hg thresholds for several conditions of severe PPM only (6.9 mm Hg and mean maximum velocity value: 183.4 cm/s) whereas such value was never attained in the case of leaflet obstruction. In the case of leaflet obstruction, the maximum velocity averaged over the nine pulsed-wave Doppler locations increased by 38% for partial leaflet obstruction and 75% for a fully blocked leaflet when compared with normal conditions. Current echocardiographic criteria might be suboptimal for the detection of bileaflet mechanical heart valve malfunction. Further developments and investigations are required in order

  5. Failure of peritoneal and gallbladder shunts in a child with craniopharyngioma

    Julie Woodfield

    2013-01-01

    Full Text Available A 1-year-old girl with craniopharyngioma required external drainage of 40-50 mL/h of cerebrospinal fluid (CSF after biopsy and cyst fenestration. She developed CSF ascites following insertion of a ventriculoperitoneal (VP shunt and a distended painful gallbladder following ventriculogallbladder shunt insertion. Revision to a ventriculoatrial shunt was required. This is the first time a craniopharyngioma has been reported to cause increased CSF production. The potential mechanisms of CSF overproduction and the difficulties managing the large volume of CSF in a young child are discussed.

  6. Congenital hepatic arteriovenous fistula with intrahepatic portosystemic shunt and aortic stenosis in a dog

    Examination of a 2-month-old male golden retriever presented to the hospital revealed malnutrition, ascites, cardiac murmur and hyperammonemia. Identification of subaortic stenosis and hepatic arteriovenous fistula was made through ultrasonography and angiocardiography. In addition, intrasurgical mesenteric portography showed an intrahepatic portosystemic shunt. The dog did not show portal hypertension and secondary multiple extrahepatic portosystemic shunts. Surgical correction was attempted after medical treatment. The hepatic artery branch which was connected to the hepatic arteriovenous fistula was separated, and completely ligated using silk ligature. However, the separation of the intrahepatic shunt blood vessel was unsuccessful and the dog died 15 hr postoperatively

  7. Simulation and reliability analysis of shunt active power filter based on instantaneous reactive power theory

    CUI Yu-long; LIU Hong; WANG Jing-qin; SUN Shu-guang

    2007-01-01

    This paper first discusses the operating principle ofinstantaneous reactive power theory. Then, the theory is introduced into shunt active power filter and its control scheme is studied. Finally, Matlab/Simulink power system toolbox is used to simulate the system. In the simulation model, as the most common harmonic source, 3-phase thyfistor bridge rectifier circuit is constructed.The simulation results before and after the shunt active filter was switched to the system corresponding to different firing angles of the thyristors are presented and analyzed, which demonstrate the practicability and reliability of the proposed shunt active filter scheme.

  8. Mutual locking, chaos and devils staircase in two Josephson tunnel junctions with a common resistive shunt

    The authors have studied the phase-locking in a pair of individually biased, resistively and capacitively shunted Josephson junctions, coupled by a common resistive or capacitive shunt, on an analog computer. Under certain conditions locking is found to occur at all rational frequency ratios. A critical line is found in parameter space along which the steps form a complete devils staircase having a fractal dimension of 0.87. Beyond the critical line bifurcations occur on all steps following the Feigenbaum sequence to chaos. The Feigenbaum constants are recovered to a fair accuracy. Preliminary experiments with two Josephson tunnel junctions shunted on the chip by a gold-indium film are discussed

  9. A Case of Discontinued Proximal Limb of a Ventriculoperitoneal Shunt With Patent Fibrous Tract.

    Bermo, Mohammed; Leung, Alan S; Matesan, Manuela

    2016-06-01

    Radionuclide shuntogram is important in the evaluation of cerebrospinal fluid (CSF) shunts complications such as mechanical failure, malpositioning, pseudocyst, or overdrainage. We present here a case of congenital hydrocephalus and posterior fossa cyst with multiple shunt procedures and revisions with breakage of the proximal tube of the ventriculoperitoneal shunt but preserved CSF drainage through the patent fibrous tract. Careful correlation with SPECT/CT images helped confirm the breakage and exclude CSF leak outside of the tract, which was suspected on planar images. PMID:26914568

  10. Tunable acoustic waveguide based on vibro-acoustic metamaterials with shunted piezoelectric unit cells

    Kwon, Byung-Jin; Jung, Jin-Young; Lee, Dooho; Park, Kwang-Chun; Oh, Il-Kwon

    2015-10-01

    We propose a new class of acoustic waveguides with tunable bandgaps (TBs) by using vibro-acoustic metamaterials with shunted periodic piezoelectric unit cells. The unit metamaterial cells that consist of a single crystal piezoelectric transducer and an electrical shunt circuit are designed to induce a strong vibro-acousto-electrical coupling, resulting in a tunable acoustic bandgap as well as local structural resonance and Bragg scattering bandgaps. The present results show that the TB frequency can be actively controlled and the transmission loss of the acoustic wave can be greatly improved by simply changing the inductance values in the shunt circuit.

  11. Association of Genetic Polymorphisms of Renin–Angiotensin–Aldosterone System-Related Genes with Arterio-Venous Fistula Malfunction in Hemodialysis Patients

    Chen, Yu-Wei; Wu, Yu-Te; Lin, Jhin-Shyaun; Yang, Wu-Chang; Hsu, Yung-Ho; Lee, Kuo-Hua; Ou, Shou-Ming; Chen, Yung-Tai; Shih, Chia-Jen; Lee, Pui-Ching; Chan, Chia-Hao; Chung, Ming-Yi; Lin, Chih-Ching

    2016-01-01

    Hemodialysis (HD) is the most commonly-used renal replacement therapy for patients with end-stage renal disease worldwide. Arterio-venous fistula (AVF) is the vascular access of choice for HD patients with lowest risk of infection and thrombosis. In addition to environmental factors, genetic factors may also contribute to malfunction of AVF. Previous studies have demonstrated the effect of genotype polymorphisms of angiotensin converting enzyme on vascular access malfunction. We conducted a m...

  12. Heparin-induced thrombocytopenia associated with acute liver graft failure

    Pannicke, Nadine; Pollok, Joerg-Matthias; Kluge, Stefan; Petzoldt, Martin

    2012-01-01

    An orthotopic liver transplantation (OLT) is of a proven benefit in an acute liver failure (ALF). Heparin-induced thrombocytopenia (HIT) is strongly associated with thromboembolic complications. We present the case of a 56-year-old patient who underwent an OLT owing to an ALF of unknown aetiology. HIT type II with consecutive hepatic and portal vein thrombosis caused progressive graft failure. Total hepatectomy and porto-caval shunt were performed to reduce the toxic effects of liver cell nec...

  13. Acute Bronchitis

    ... of bronchitis: acute and chronic. Most cases of acute bronchitis get better within several days. But your cough ... that cause colds and the flu often cause acute bronchitis. These viruses spread through the air when people ...

  14. Experimental study on absorption of blade vibration of honeycomb seal and shunt injection

    Zhang Qiang; He Lidong; Huo Genglei; Che Jianye

    2008-01-01

    Honeycomb seals and shunt injection have been proposed to weaken the blade vibration. Honeycomb seals, as well as, smooth seals were tested with different seals' clearances and shrouded blades. The shunt injection was sprayed to the blade tip clearance in the reverse direction of the main flow. Experimental results showed that both honeycomb seals and shunt injection had the damping effect for blade vibration, and the blade vibration magnitude could be reduced by more than 25% and 17%, respectively. When the two methods were adopted synchronously, more than 1/3 of the blade vibration could be reduced. Consequently, adopting honeycomb seal and superinducing proper shunt injection are two useful ways to minimize vibration of the blade from the viewpoints of avoiding blade rupture and improving the rotor stability.

  15. Shunt hybrid active power filter for harmonic mitigation: A practical design approach

    Unnikrishnan A K; Chandira Sekaran E; Subhash Joshi T G; Manju A S; Aby Joseph

    2015-06-01

    The increasing importance of Power Quality problems has been responsible for several improvements in Active Power Filter (APF) typologies in the last decade. The increased cost and switching losses make a pure shunt APF economically impractical for high power applications. In higher power levels shunt Hybrid Active Power Filter (HAPF) has been reported to be a useful approach to eliminate current harmonics caused by nonlinear loads. This paper presents a control strategy and design criteria for transformer-less shunt HAPF with special attention to the integration of series passive filter. The paper also compares the performance improvement of passive harmonic filter when modified as shunt HAPF. Experimental results obtained verify the viability and effectiveness of the proposed design criteria and control algorithm.

  16. Optimizing the Shunting Schedule of Electric Multiple Units Depot Using an Enhanced Particle Swarm Optimization Algorithm.

    Wang, Jiaxi; Lin, Boliang; Jin, Junchen

    2016-01-01

    The shunting schedule of electric multiple units depot (SSED) is one of the essential plans for high-speed train maintenance activities. This paper presents a 0-1 programming model to address the problem of determining an optimal SSED through automatic computing. The objective of the model is to minimize the number of shunting movements and the constraints include track occupation conflicts, shunting routes conflicts, time durations of maintenance processes, and shunting running time. An enhanced particle swarm optimization (EPSO) algorithm is proposed to solve the optimization problem. Finally, an empirical study from Shanghai South EMU Depot is carried out to illustrate the model and EPSO algorithm. The optimization results indicate that the proposed method is valid for the SSED problem and that the EPSO algorithm outperforms the traditional PSO algorithm on the aspect of optimality. PMID:27436998

  17. The transjugular portosystemic stent shunt (TIPSS) as an intervention in clinical complication of portal hypertension

    Most frequent complications in patients with liver cirrhosis are due to portal hypertension. Beside ascites circumvent vessles formate with vasodilatation. Due to counterregulation a secondary hyperaldosteronism develops with release of vasocontrictive agents. If conservative and endoscopic methods fail, indication for building a portosystemic shunt is given. The TIPSS procedure is less invasive than the surgical method of Warren-Shunt, so the radiological intervention has replaced surgery. Reducing the portal pressure by the shunt, the clinical complications change for the better. Still problems are defined as hepatic encephalopathy and right ventricular heart failure. Regular follow up investigations have to be performed to detect complications in the shunt. Using regular clinical and radiological check up TIPSS is of clinical benefit with good long term results. (orig.)

  18. Relation between Shunt, Aeration, and Perfusion in Experimental Acute Lung Injury

    Musch, Guido; Bellani, Giacomo; Vidal Melo, Marcos F; Harris, R. Scott; Winkler, Tilo; Schroeder, Tobias; Venegas, Jose G

    2007-01-01

    Rationale: In a pulmonary process characterized by spatially heterogeneous loss of aeration, the impairment of gas exchange is expected to depend on the regional distribution of perfusion relative to that of aeration.

  19. Palliative embolisation for intrapulmonary shunting in lepidic predominant adenocarcinoma of the lung

    Joanne Yue-Ai Tan

    2015-01-01

    Full Text Available Lepidic predominant adenocarcinoma (LPA (formerly known as bronchioalveolar carcinoma has rarely been reported to cause refractory hypoxia with intrapulmonary shunting [1–7]. We describe a case who underwent the palliative strategy of intravascular right lower pulmonary artery embolisation with an 18 mm Amplatzer II vascular plug to reduce intrapulmonary shunting. This is the first report we are aware of using this minimally invasive procedure to treat this condition.

  20. Cerebral Venous Thrombosis Complicated by Hemorrhagic Infarction Secondary to Ventriculoperitoneal Shunting

    Son, Won-Soo; Park, Jaechan

    2010-01-01

    While a delayed intracerebral hemorrhage at the site of a ventricular catheter has occasionally been reported in literature, a delayed hemorrhage caused by venous infarction secondary to ventriculoperitoneal shunting has not been previously reported. In the present case, a 68-year-old woman underwent ventriculoperitoneal shunting through a frontal burr hole, and developed a hemorrhagic transformation of venous infarction on the second postoperative day. This massive venous infarction was caus...

  1. Alterations in the aqueous humor proteome in patients with a glaucoma shunt device

    Anshu, Arundhati; Price, Marianne O; Richardson, Matthew R; Segu, Zaneer M.; Lai, Xianyin; Yoder, Mervin C.; Price, Francis W.

    2011-01-01

    Purpose To investigate whether implantation of a glaucoma shunt device leads to inappropriate accumulation of plasma derived proteins in the aqueous humor. Methods Aqueous humor samples were collected from 11 patients (study group) with a glaucoma shunt device undergoing either cataract surgery or a corneal transplant and 11 patients (control) with senile cataract undergoing routine cataract extraction. Of the study group, 9 had an Ahmed valve implant and 2 eyes had a Baerveldt implant. Trypt...

  2. Investigation of the hydrodynamic properties of a new MRI-resistant programmable hydrocephalus shunt

    Pickard John D; Richards Hugh K; Czosnyka Marek; Allin David M; Czosnyka Zofia H

    2008-01-01

    Abstract Background The Polaris valve is a newly released hydrocephalus shunt that is designed to drain cerebrospinal fluid (CSF) from the brain ventricles or lumbar CSF space. The aim of this study was to bench test the properties of the Polaris shunt, independently of the manufacturer. Methods The Polaris Valve is a ball-on-spring valve, which can be adjusted magnetically in vivo. A special mechanism is incorporated to prevent accidental re-adjustment by an external magnetic field. The perf...

  3. Scintigraphic evaluation of hepatic blood flow after intrahepatic portosystemic shunt (TIPS)

    Menzel, J. [Department of Medicine B, University of Muenster, Muenster (Germany); Schober, O. [Department of Nuclear Medicine, University of Muenster, Muenster (Germany); Reimer, P. [Department of Radiology, University of Muenster, Muenster (Germany); Domschke, W. [Department of Medicine B, University of Muenster, Muenster (Germany)

    1997-06-10

    In patients with liver cirrhosis a transjugularly placed intrahepatic portocaval shunt (TIPS) is a non-surgical portosystemic device which aims to reduce portal venous pressure. In comparison with Doppler sonography, we evaluated in 28 patients the diagnostic impact of liver perfusion scintigraphy (with technetium-99m diethylene triamine penta-acetic acid) in the assessment of changes in the hepatic blood flow after TIPS shunting. The arterial and portal contributions to hepatic flow were calculated from the areas under the biphasic time-activity curve. In the course of TIPS shunting, patency is threatened by reocclusion. Angiography is the gold standard for TIPS shunt reassessment. However, there is a need for a less invasive diagnostic procedure, such as scintigraphy or Doppler sonography, for the early detection of shunt insufficiency. Scintigraphy demonstrated that prior to TIPS shunting the portal venous contribution to hepatic perfusion was reduced to 29.2%, this reduction being due to portal hypertension. After TIPS placement a significant increase in portal venous perfusion was observed (38.2%; P<0.02). TIPS shunt occlusion was identified in patients by a significant reduction in the scintigraphically measured portal venous contribution to hepatic blood flow. Hepatic perfusion scintigraphy appears to be a valuable method to determine the immediate effect of TIPS on hepatic blood flow. Post-TIPS follow-up studies of hepatic haemodynamics by liver perfusion scintigraphy appear able to contribute to the detection of TIPS shunt occlusion before the clinical consequences of this complication have become apparent. (orig.). With 4 figs., 3 tabs.

  4. Radionuclide assessment of LeVeen shunt patency. [/sup 99m/Tc tracer technique

    Kirchmer, N.; Hart, U.

    1977-02-01

    Patients with an initially satisfactory result following placement of a LeVeen peritoneo-venous shunt for intractable ascites may reaccumulate massive ascites. Determination of the etiology of such is a difficult problem. We describe a simple method using intraperitoneal injection of Technetium-99m sulfur colloid and three gamma camera scintiphotos of the chest and abdomen to allow prompt determination of shunt occlusion as the cause.

  5. Congenital hepatoportal arteriovenous fistula associated with intrahepatic portal vein aneurysm and portohepatic venous shunt: case report

    Lee, Jin Hwa; Shin, Tae Beom; Kang, Myong Jin; Yoon, Seong Kuk; Oh, Jong Young; Choi, Jong Cheol; Park, Byeong Ho; Choi, Sun Seob; Nam, Kyung Jin [College of Medicine, Donga University, Busan (Korea, Republic of)

    2005-08-15

    A congenital hepatoportal arteriovenous fistula associated with an intrahepatic portal vein aneurysm is a rare type of arteriovenous malformation. Only 14 pediatric cases have been reported to the best of the authors' knowledge. An intrahepatic shunt between the portal and systemic veins is also relatively rare. We report a case of a congenital hepatoportal arteriovenous fistula associated with an intrahepatic portal vein aneurysm and a portohepatic venous shunt in a neonate who presented with tachypnea and melena.

  6. Superconducting FCL using a combined inducted magnetic field trigger and shunt coil

    Tekletsadik, Kasegn D. (Rexford, NY)

    2007-10-16

    A single trigger/shunt coil is utilized for combined induced magnetic field triggering and shunt impedance. The single coil connected in parallel with the high temperature superconducting element, is designed to generate a circulating current in the parallel circuit during normal operation to aid triggering the high temperature superconducting element to quench in the event of a fault. The circulating current is generated by an induced voltage in the coil, when the system current flows through the high temperature superconducting element.

  7. Color doppler in the diagnosis of a congenital intrahepatic portosystemic venous shunt in a newborn

    Intrahepatic portosystemic venous shunts are rare. To date, only 28 cases have been reported, mostly in adults with liver cirrhosis, although congenital cases have also been described. We present a case of intrahepatic portosystemic venous shunt in a newborn that was diagnosed by color Doppler ultrasound. We stress the role of color Doppler as the technique of choice in the study of hepatic lesions of vascular origin. (Author) 7 refs

  8. Liver atrophy following portacaval shunt in normal rats: A morphologic and ultrastructural study

    Radosavljević Tatjana; Todorović Vera N.; Boričić Ivan V.; Šikić Branka

    2003-01-01

    The aim of the current study was to examine morphological and ultrastructural changes in the rat liver in an experimental model of chronic liver disease (end-to-side portacaval shunt). The surgical procedure providing an end-to-side portacaval shunt (PCS) was performed in Wistar rats. The liver and pancreas weights were determined 8 weeks after the operation, when liver histology and ultrastructural patterns of hepatocytes were examined. Body weights were not significantly different between t...

  9. Grid Connected Wind Energy Conversions System Performance is Improved by Switching of Shunt Active Filter

    B.Vaikundaselvan; Ranithottungal

    2014-01-01

    This study presents a Grid connected Wind Energy Conversions System (WECS) where performance is improved by switching of Shunt Active Filter. Shunt active filter for non linear loads is designed to minimize the harmonics present in the wind power system. Due to large penetration of power electronic controllers in the wind power applications, switching of these power electronic circuits induces harmonics in the source which causes undesirable effects on the wind energy conversion systems and t...

  10. Noninvasive measurement of nutrient portal blood shunting: an experimental study with [14C]ursodeoxycholic acid

    All of the methods proposed for measuring portal blood flow are either invasive, estimate total rather than nutrient flow, and none has proved reliable in cirrhotic patients. A method has been derived from pharmacokinetic principles used for the calculation of bioavailability of drugs according to the route of administration (i.v. or p.o.) and tested experimentally in 20 pigs. A tracer dose of [14C]ursodeoxycholic acid, a biliary acid with a high-liver first-pass effect, is administered in the duodenum, and serial peripheral blood samples are taken. Later, the same dose of the same drug is administered i.v. The shunt fraction of portal blood F is obtained by the ratio of the areas under the plasma level vs. time curves (AUC) after p.o. and i.v. administrations: (see formula in text). The pigs were divided into three experimental groups. (i) Group I: undisturbed portal flow; (ii) Group II: total diversion of portal blood with an end-to-side portacaval shunt, and (iii) Group III: partial diversion of portal blood through a side-to-side portacaval shunt. Portal flow was measured during surgery with an electromagnetic flowmeter above and below the shunt and the degree of shunting calculated. Results show that the shunt fraction measured with ursodeoxycholic acid is well-correlated with hemodynamic data. No overlap between Groups I and III is observed. It is concluded that the shunt fraction of nutrient portal blood can be measured with this noninvasive method. Minute amounts of ursodeoxycholic acid were used in order to be completely metabolized by the liver, even in spite of hepatocellular dysfunction. Therefore, this method should be valid in cirrhotic patients and be useful to decide the type of portasystemic shunt to propose for the decompression of gastroesophageal varices

  11. What are the implications of the spontaneous spleno-renal shunts in liver cirrhosis?

    Cirillo Michele; Capone Domenico; Tarantino Marianna; Riccio Antonio; Conca Paolo; Citro Vincenzo; Tarantino Giovanni; Lobello Roberto; Iaccarino Vittorio

    2009-01-01

    Abstract Background Although significant advances are expected to be made in the assessment of the portal hypertension-related complications, the prognostic role of spleno-renal shunts has not been fully explored so far. Clarifying this aspect could help tackle the life-treating events occurring in patients suffering from liver cirrhosis. The aim of the study was to analyze the relationships between the spleno-renal shunts presence at doppler ultrasound and the liver cirrhosis complications. ...

  12. Goel′s Teflon sponge internal shunt for anterior spinal arachnoid cyst

    Raghvendra Ramdasi; Abhidha Shah

    2014-01-01

    We report a case of a 6-year-old boy who presented with progressive quadriparesis and bowel-bladder incontinence. Magnetic resonance imaging (MRI) of the spine showed anteriorly located arachnoid cyst in the cervicodorsal region. Following marsupialization of the cyst, an internal Teflon sponge shunt (Goel's shunt) was done that extended from the cyst cavity to the subarchnoid space. The patient improved dramatically in his symptoms. The physical nature of the teflon sponge and its usefulness...

  13. Spontaneous expectoration of a Blalock-Taussig shunt a decade after operation

    Shyam S Kothari

    2015-01-01

    Full Text Available An eleven-year-old boy expectorated a foreign body in cough that was identified as the prosthetic graft used for a Blalock-Taussig shunt. The shunt procedure was done 10 years earlier, and a definitive repair for tetralogy of Fallot was done a year later. He had no other symptoms, and a computed tomography (CT angiogram did not reveal any other significant anomaly. The reason for this extremely rare event is unclear.

  14. Congenital hepatoportal arteriovenous fistula associated with intrahepatic portal vein aneurysm and portohepatic venous shunt: case report

    A congenital hepatoportal arteriovenous fistula associated with an intrahepatic portal vein aneurysm is a rare type of arteriovenous malformation. Only 14 pediatric cases have been reported to the best of the authors' knowledge. An intrahepatic shunt between the portal and systemic veins is also relatively rare. We report a case of a congenital hepatoportal arteriovenous fistula associated with an intrahepatic portal vein aneurysm and a portohepatic venous shunt in a neonate who presented with tachypnea and melena

  15. The Analysis of Shunting Locomotives’ Operating Efficiency Based on Gray-DEA

    Yunli Zhang; Dingyou Lei; Xiamiao Li; Yanbing Fu

    2013-01-01

    In order to explore the configuration of the railway freight shunting locomotives, improve the efficiency of locomotive operation; a DEA cross evaluating method based on grey incidence analysis is presented in this paper. This method is based on collecting underlying data of factors that influence the shunting operation efficiency in train service depot, which utilizes grey incidence analysis to establish corresponding evaluation indicators system. Furthermore, the method as well adopts DEA a...

  16. The Analysis of Shunting Locomotives’ Operating Efficiency Based on Gray-DEA

    Yunli Zhang

    2013-02-01

    Full Text Available In order to explore the configuration of the railway freight shunting locomotives, improve the efficiency of locomotive operation; a DEA cross evaluating method based on grey incidence analysis is presented in this paper. This method is based on collecting underlying data of factors that influence the shunting operation efficiency in train service depot, which utilizes grey incidence analysis to establish corresponding evaluation indicators system. Furthermore, the method as well adopts DEA and DEA cross efficiency model to analyze, evaluate and estimate the efficiency of shunting locomotives operation in train service depots. A sorting result of the efficiency of shunting locomotives operation in each train service depot has been acquired with help of programming using MATLAB 7.0. What the result indicates is that the DEA cross efficiency evaluating model based on grey incidence analysis can reflect the actual state of the efficiency of shunting locomotives operation in each train service depot. Eventually, based on a projection analysis of non-DEA's three decision-making units, key factors that influence the efficiency of shunting locomotives operation are identified, which can provide decision support for further improvement of the configuration and operation in train service depots.

  17. Severe Intraoperative Hypercapnia Complicating an Unsual Malfunction of the Inner Tube of a Co-axial (BAIN'S Circuit

    Youssef Emam Youssef

    2010-04-01

    Full Text Available The Bain's co-axial circuit system is fully established in general anaesthesia practice. It is favoured for its light weight and suitability for head and neck surgery. However, there are numerous published reports of malfunction of the inner tube of the Bain's co-axial circuit, with potentially lethal complications for the patient. This report presents a case in which a patient connected to a reused Bain's circuit (Datex-Ohmeda developed severe hypercapnia in the early intraoperative period due to unusual defect of the inner tube. This report tests and outlines the integrity of co-axial circuits and also reviews the available literature.

  18. Analysis of licensee event reports related to nuclear generating station onsite electrical system malfunctions, 1976-1978

    This report summarizes the evaluation requested by the ACRS of 1177 LERS, submitted over a three year period, which related to onsite electrical system malfunctions. The evaluation was carried out for the purposes of identifying specific failure modes and consequences, evaluating the assumptions used in WASH-1400 on the reliability of electrical equipment, and identifying specific sequences which are significant to plant safety. The analysis performed provides a more specific identification of onsite electrical system failure modes, sequences, and consequences than was established in WASH-1400

  19. Treatment with interventional peritoneovenous shunts for intractable ascites

    Objective: To evaluate the value of the interventional peritoneovenous shunts (IPVS)for intractable ascites (IA). Methods: The passageway was built between abdominal cavity and superior vena cava(SVC)in 45 patients with IA. The pressure of abdominal cavity and SVC were measured during operation, the abdominal girth and the amount of urine were recorded after the operation. Results: The successful rate of operation was 100% with operation time of 20-40 min. The average difference of pressure between abdominal cavity and SVC was 129.3 cm H2O. The abdominal girth began to reduce 2 days later, and reduced obviously since then with an average of 7.8 cm. Simultaneously, the amount of urine obviously increased after operation with an average of 770 ml/d. The total effective rate reached 77.8% with no serious complications. Conclusion: IPVS has advantages of simple operation, minimal trauma and convenient for patients with IA nursing themselves etc. and thus improve the living quality of patients exactly. (authors)

  20. Hyperglucagonemia and hyperkinetic circulation after portocaval shunt in the rat

    The study was aimed at investigating whether increased portal venous inflow (PVI) after portocaval shunt (PCS) in the rat is the result of selective splanchnic vasodilatation or whether it is part of a generalized circulatory disturbance. Rats with PCS and sham-operated controls were studied 2 wk after surgery by measuring cardiac output (CO), PVI, and hepatic artery flow (HAF) with radioactive microspheres (51Cr and 14C). Plasma glucagon (GL) was measured by radioimmunoassay. PCS rats had increased CO and reduced arterial pressure and total peripheral resistance. PVI was markedly increased, but this appeared to be part of a generalized circulatory disturbance, since when PVI is expressed as percent of CO no difference is observed between PCS and sham-operated rats, indicating the absence of a preferential splanchnic vasodilatation. GL increased after PCS, and significant correlations were observed between GL and CO and between GL and PVI. HAF increased after PCS but did not compensate the loss of portal flow, evidence by a lower total hepatic flow in PCS rats. These results suggest that PCS induces a hyperkinetic circulatory state in which increased PVI represents its splanchnic manifestation and that increased GL release may be in part responsible for these hemodynamic changes

  1. Battery Equalization Control Based on the Shunt Transistor Method

    Gallardo-Lozano Javier

    2014-12-01

    Full Text Available Electric Vehicle (EV researches are currently becoming of special importance and the EV battery system is particularly relevant in the EV design. In these applications, series connected batteries are necessary since a single battery cannot achieve the voltage requirements. Internal and external sources lead the batteries string to become unbalanced, which is an important factor to be taken into account, as premature cells degradation, safety hazards, and reduced capacity will occur for unbalanced systems. The different balancing methods are presented and compared in this paper, and finally the switch capacitor and the double-tiered switching capacitor are considered the best option. However, their speed depends on the voltage difference between the batteries in the string, and when their voltage difference is low, the equalization speed decreases significantly, leading the battery pack to be unbalanced for longer. A novel equalization method is presented, that improves the aforementioned methods performance by applying a new control to a shunt transistor method. Low cost, size, and complexity, together with higher speed and efficiency are obtained. A prototype has been built, and experimental results are presented.

  2. Oculo-peritoneal shunt: draining aqueous humor to the peritoneum

    Ana Maldonado-Junyent

    2015-04-01

    Full Text Available In 2010, there were estimated to be approximately 60.5 million people with glaucoma. This number is expected to increase to 79.6 million by 2020. In 2010, there were 8.4 million people with bilateral blindness caused by glaucoma, and this number is expected in increase to 11.2 million by 2020. Filtering implants are special devices that have been developed to reduce intraocular pressure in patients with refractory glaucoma. The success rate of these implants is relatively low, and they continue to fail over time. To avoid failure caused by the formation of scar tissue around the implants, attempts have been made to drain the aqueous humor to various sites, including the venous system, lacrimal sac, sinuses, and conjunctival fornix. Recently, a system to shunt aqueous humor from the anterior chamber to the peritoneum has been developed. The surgical technique involved in this system is a modification of the technique currently used by neurosurgeons for the treatment of hydrocephalus. We present the first case operated using this technique.

  3. Methionine metabolism after portacaval shunt in the rat

    The effect of portacaval shunt (PCS) on methionine metabolism in the rat was investigated. Male Sprague-Dawley rats were subjected to PCS and maintained on an 18% casein diet. Growth curves of operated rats were similar to controls. PCS rats excreted more urinary 35SO4 and less [35S]taurine than controls after intraperitoneal injection of 0.3 mmol/100 g [35S]methionine or [35S]cysteine. Total urinary taurine excretion was similar in PCS and control rats after a methionine or cysteine load; however, under basal conditions PCS rats had higher urinary taurine levels than controls, indicating that PCS may cause the taurine pool to be expanded. Hepatic methionine, S-adenosylmethionine, and cysteine pools were significantly decreased in PCS rats, while S-adenosylhomocysteine levels were unchanged. Relative rates of transsulfuration in PCS and control rats were studied by following the decrease in the 3H-to-35S ratio in liver protein after injection of [methyl-3H]methionine and [35S]methionine, and no difference in flux of 35S from [35S]methionine to [35S]cysteine was found. Similarly, total hepatic activities of methionine adenosyltransferase, cystathionine synthase, and cystathionine gamma-lyase were unchanged in PCS rats. These results indicate that altered methionine metabolism in PCS rats is not explained by changes in conversion of methionine to cysteine via the transsulfuration pathway

  4. Right-to-left shunt is common in chronic migraine.

    Nahas, S J; Young, W B; Terry, R; Kim, A; Van Dell, T; Guarino, A J; Silberstein, S D

    2010-05-01

    Our aim was to determine the prevalence of right-to-left shunt (RtLS) in patients with chronic migraine (CM), and to correlate the presence and grade of RtLS with aura and neurological symptoms, and duration and severity of disease. The prevalence of RtLS in migraine without aura is similar to that of the general population (between 20 and 35%). In migraine with aura, the prevalence is much higher (approximately 50%). The prevalence in CM, with or without aura, is unknown. Consecutive patients between the ages of 18 and 60 years with CM attending a tertiary care specialty headache clinic over an 8-week period were eligible. There were 131 patients in the study. A structured diagnostic interview was performed. Bubble transcranial Doppler with Valsalva manoeuvre determined RtLS presence and grade. Sixty-six percent (86/131) of patients had RtLS, a statistically significantly greater rate than those reported in the general population and in migraine with or without aura (P RtLS rate or grade between those with and those without aura. Specific headache features and the presence of neurological symptoms were similar between those with and those without RtLS. Compared with both the general population and the episodic migraine population (with and without aura), patients with CM, with or without aura, are more likely to have RtLS. The clinical implications of our findings need to be determined. PMID:19732069

  5. Effects of isradipine and other calcium antagonists on arteriovenous-shunt flow in anesthetized rabbits and cats

    Hof, R.P.

    1989-04-17

    The effects of vasodilators on arteriovenous (AV)-shunt flow was investigated in anesthetized cats and rabbits, using the tracer microsphere method. In cats, the calcium antagonist isradipine reduced AV-shunt flow; verapamil showed a similar tendency and nicardipine was without effect. Dihydralazine strongly increased, but nitroglycerin and dipyridamole decreased AV-shunt flow. In rabbits, the effects of isradipine and verapamil were similar to those seen in cats. Sodium nitroprusside had no effect, whereas prazosin, minoxidil, and the potassium-channel activator cromakalim increased AV-shunt flow. The contrasting effects of drugs sharing the same mechanism of action suggest that target-tissue selectivity is more important than the mechanism of action. An increase of AV-shunt flow is unlikely to be beneficial but could be associated with a number of undesirable side effects. It might negatively affect migraine sufferers and, if AV-shunt dilatation shows no tolerance development, it represents an unnecessary hemodynamic burden for the heart.

  6. Ventriculo-bipleural shunt as last resort in a 4-year-old child in whom a VP and VA shunt failed.

    Ratliff, Miriam; Unterberg, Andreas; Bächli, Heidi

    2016-03-01

    The authors present the unusual case of a 4-year-old boy who had a complex history of posthemorrhagic hydrocephalus and who underwent more than 40 surgeries related to this condition. In the course of trying to treat his condition, ventriculoperitoneal, ventriculoatrial, and ventriculopleural shunts were inserted and failed. The child presented with a dysfunction of his shunt system. A ventriculopleural shunt was inserted, but within days the patient developed dyspnea as a clinical symptom of pleural effusion that required repeated thoracentesis. A bipleural drainage system was inserted, and no relevant pleural effusions developed during the follow-up period. Although the authors' experience is based on a single case, they do suggest bipleural drainage in patients with clinically relevant pleural effusions when the more common alternatives are not a good choice. Bipleural drainage might particularly be an option in children, who are prone to pleural effusion because of the smaller absorbing pleural surface. The authors reviewed the English-language literature on PubMed dating back to 1952. To their knowledge, this is the only published case in which a patient was treated with a ventriculo-bipleural shunt. PMID:26613270

  7. Universal statistics of parasitic shunt formation in solar cells, and its implications for cell to module efficiency gap

    Dongaonkar, Sourabh; Alam, Muhammad A.

    2013-01-01

    Parasitic shunt formation is an important cause of variability and module efficiency loss in all photovoltaic technologies. In this letter, we quantify the nature of this shunt variability in fourmajor thin film photovoltaic (TFPV) technologies, namely, amorphous silicon (a-Si:H), organic (OPV), Cu(In,Ga)SSe (CIGS), and CdTe. We analyze a wide variety of datasets to show that the shunt current exhibits a robust universal log-normal behavior for all these technologies. We affirm this conclusio...

  8. Spontaneous resolution of splenic infarcts after distal splenorenal shunt in children with extra hepatic portal venous obstruction: Our experience

    Arbinder Kumar

    2014-01-01

    Full Text Available Background: In cases of portal hypertension with splenic infarcts, splenectomy with proximal splenorenal shunt has been recommended. We are sharing our experience with distal splenorenal shunt in these cases contrary to the popular belief. Materials and Methods: Splenic infarcts were graded as mild, moderate and severe according to the pre-operative CT portogram. Mild, moderate and severe infarcts were defined as an infarct involving 50% area of the spleen, respectively. Mild and moderate infarcts were managed by spleen-preserving distal splenorenal shunt while those with extensive infarcts were subjected to splenectomy and proximal splenorenal shunt. Those with spleen-preserving shunts were closely followed in the post-operative period according to a uniform protocol. Clinical examination was regularly done to assess the size of the spleen and note the presence of pain, tenderness in the left intercostal space. An ultrasound Doppler was done after 7 days to assess shunt patency while CT portogram was repeated at 6 monthly intervals. Results: Fourteen cases with splenic infarcts formed the study group. Eight cases had mild infarcts, 3 had moderate infarcts and 3 had severe infarcts. Four underwent proximal splenorenal shunt, and 10 underwent warren′s shunt (8 with mild and 2 with moderate infarcts. In 9/10 (90%, spleen could eventually be retained. Spleen completely regressed in them and so did the infarct. Conclusions:Spleen-preserving distal splenorenal shunt can be considered as a viable option in the management of cases with mild and carefully selected moderate splenic infarcts.

  9. Cerebral Blood Flow Changes after Shunt in Hydrocephalus after Aneurysmal Subarachnoid Hemorrhage: Analysis by statistical Parametric Mapping

    The purpose of this study was to evaluate the changes of regional cerebral blood flow (rCBF) after shunt operation in patients with hydrocephalus after aneurysmal subarachnoid hemorrhage ba statistical parametric mapping (SPM). Seven patients (4 male, mean age 54 years) with hydrocephalus after aneurysmal subarachnoid hemorrhage underwent a shunt operation. Tc-99m HMPAO SPECT was performed within I week before, and 2 weeks after the shunt operation. All of the SPECT images were spatially transformed to standard space, smoothed, and globally normalized. After spatial and count normalization, rCBF of pre- and post- shunting Tc- 99m HMPAO SPECT was estimated at every voxel using t statistics. The voxels with a P value of less than 0.001 were considered to be significantly different. The shunt operation was effective in all patients. Pre-shunting Tc-99m HMPAO SPECT showed hypoperfusion, predominantly in the periventricular area. After shunt operation, periventricular low perfusion was disappeared. The results of this study show that periventricular CBF is impaired in hydrocephalus after aneurysmal subarachnoid hemorrhage. Significant increase of periventricular CBF after shunt operation suggests the evaluation of periventricular CBF by SPM might be of value for the prediction of shunt effectiveness in hydrocephalus

  10. Peritoneovenous shunt in treatment of ascites in patients with cirrhosis. A preliminary report with special reference to pathophysiology

    Henriksen, Jens Henrik Sahl; Malchow-Møller, A; Ring-Larsen, H;

    1983-01-01

    severely impaired liver and kidney function. In two of the four surviving patients (observation time, 5-24 months) the shunt was patent during the observation time, and ascites disappeared. In the other two the shunt closed, in one patient repeatedly following several re-implantations. Enhanced urinary...... sodium excretion was observed in patients with patent shunts. After disappearance of ascites, the splanchnic venous pressures became less deranged. Long-term change in plasma volume or circulating albumin mass could not be detected. A patent shunt increases the drainage from the peritoneal cavity, but...

  11. Impact of cerebrospinal fluid shunting for idiopathic normal pressure hydrocephalus on the amyloid cascade.

    Masao Moriya

    Full Text Available The aim of this study was to determine whether the improvement of cerebrospinal fluid (CSF flow dynamics by CSF shunting, can suppress the oligomerization of amyloid β-peptide (Aβ, by measuring the levels of Alzheimer's disease (AD-related proteins in the CSF before and after lumboperitoneal shunting. Lumbar CSF from 32 patients with idiopathic normal pressure hydrocephalus (iNPH (samples were obtained before and 1 year after shunting, 15 patients with AD, and 12 normal controls was analyzed for AD-related proteins and APLP1-derived Aβ-like peptides (APL1β (a surrogate marker for Aβ. We found that before shunting, individuals with iNPH had significantly lower levels of soluble amyloid precursor proteins (sAPP and Aβ38 compared to patients with AD and normal controls. We divided the patients with iNPH into patients with favorable (improvement ≥ 1 on the modified Rankin Scale and unfavorable (no improvement on the modified Rankin Scale outcomes. Compared to the unfavorable outcome group, the favorable outcome group showed significant increases in Aβ38, 40, 42, and phosphorylated-tau levels after shunting. In contrast, there were no significant changes in the levels of APL1β25, 27, and 28 after shunting. After shunting, we observed positive correlations between sAPPα and sAPPβ, Aβ38 and 42, and APL1β25 and 28, with shifts from sAPPβ to sAPPα, from APL1β28 to 25, and from Aβ42 to 38 in all patients with iNPH. Our results suggest that Aβ production remained unchanged by the shunt procedure because the levels of sAPP and APL1β were unchanged. Moreover, the shift of Aβ from oligomer to monomer due to the shift of Aβ42 (easy to aggregate to Aβ38 (difficult to aggregate, and the improvement of interstitial-fluid flow, could lead to increased Aβ levels in the CSF. Our findings suggest that the shunting procedure can delay intracerebral deposition of Aβ in patients with iNPH.

  12. What are the implications of the spontaneous spleno-renal shunts in liver cirrhosis?

    Cirillo Michele

    2009-11-01

    Full Text Available Abstract Background Although significant advances are expected to be made in the assessment of the portal hypertension-related complications, the prognostic role of spleno-renal shunts has not been fully explored so far. Clarifying this aspect could help tackle the life-treating events occurring in patients suffering from liver cirrhosis. The aim of the study was to analyze the relationships between the spleno-renal shunts presence at doppler ultrasound and the liver cirrhosis complications. Methods Design: eighty one patients out of 129 formed the study population (35 females. Chronic liver damage in these patients was caused by HCV (66, HBV (2, alcohol abuse (2 or unknown etiology, likely non-alcoholic steatohepatitis (11. Setting: two Liver Units of university/primary hospitals in Southern Italy. Main outcome measures: grading of esofageal varices; detection of ascites: assessment of hepatic encephalopathy; evaluation of liver cirrhosis severity; tracking hepatocellular carcinoma; doppler features of spleno-renal shunts and splenic flow velocity; spleen longitudinal diameter at sonography. Results The prevalence of spleno-renal shunts was 18.5%, without no difference concerning the etiology (HCV versus non-HCV, p = 0.870; the prevalence of hepatocellular carcinoma in patients with spleno-renal shunts was superior to that of patients without them (Pearson Chi-square, p = 0.006, power of sample size 74%, also after adjustment for liver decompensation (p = 0.024. The median score of hepatic encephalopathy in patients with and without spleno-renal shunts was similar, i.e., 0 (range, 0-2 versus 0 (0 - 3, p = 0.67. The median splenic vein flow velocity in patients with spleno-renal shunts was significantly inferior to that of patients without them, i.e., 13 cm/sec (95% confidence intervals, 6-18 versus 21 cm/sec (17-24, p Conclusion Taking into consideration the relatively small sample size, patients with spleno-renal shunts are burdened by an

  13. Unified power flow controller based on two shunt converters and a series capacitor

    Khoshkbar Sadigh, Arash; Tarafdar Hagh, Mehrdad; Sabahi, Mehran [Faculty of Electrical and Computer Engineering, University of Tabriz, Tabriz (Iran)

    2010-12-15

    In this paper a novel configuration of unified power flow controller (UPFC) which consists of two shunt converters and a series capacitor is proposed. In this configuration, a series capacitor is used between two shunt converters to inject desired series voltage. As a result, it is possible to control the active and reactive power flow as same as the conventional configuration of UPFC. The main advantage of the proposed UPFC in comparison with the conventional configuration is injection of a series voltage waveform with a very low total harmonic distortion (THD). Also, using two shunt converters instead of a series and a shunt converters, results in reduction of design efforts and simplification of control, measuring and protection strategies. An optimal control strategy based on the discrete model of converters is applied to shunt converters. The proposed UPFC is simulated using PSCAD/EMTDC and MATLAB software and simulation results are presented to validate the effectiveness of the novel configuration of UPFC. Also, the experimental results which are obtained from an experimental set-up are presented. (author)

  14. [Lymphangiomyomatosis with chylous ascites treatment successfully by peritoneo-venous shunting].

    Kimura, M; Morikawa, T; Takeuchi, K; Furuie, H; Fukimura, M; Mikami, R; Kakuta, Y; Kawamura, S; Tashiro, Y

    1996-05-01

    A 49-year-old woman was admitted to our hospital because of coughing and dyspnea. A chest roentogenogram showed emphysematous changes and a diffuse reticular shadow. A high-resolution CT scan of the chest showed many small cysts throughout the lungs. Lymphangiomyomatosis was diagnosed after examination of a specimen obtained by transbronchial biopsy. Abdominal distention due to chylous ascites developed during the hospital stay despite anti-estrogen therapy. Because the ascites was resistant to conservative therapy, we decided to begin peritoneo-venous shunting with a Denver Shunt system. After the operation, the abdominal distention was controlled for 1 year and 11 months, at which time the patient died of respiratory and heart failure with pneumonia. At autopsy, the shunt was patent and functional although about 900 ml of serous ascites fluid was present. An adenocarcinoma was found in the upper lobe of the right lung, but it may not have been related to the lymphangiomyomatosis. Peritoneovenous shunting with a Denver Shunt can be used to treat chylous ascites due to lymphangiomyomatosis when conservative therapy is insufficient. PMID:8753114

  15. Comparison of series regulated neutral beam accel supplies with shunt regulated accel supplies

    This study was undertaken to get a direct comparison between comparable series and shunt regulated power supplies. It is intended that the two supplies will be strictly equivalent with the same safety factors in the design of each type and the cost estimates made on the same basis. The series regulated power supply is simply a scaled up version of the 2XIIB Accel Supplies. Each supply provides 150 kV, 65 ampere, 500 ms pulse output such as will be used on the TFTR sources. The shunt regulated power supply uses high reactance transformers to provide the series impedance for the shunt regulator. The most significant difference in the performance of the two types of power supplies is that the shunt regulated supply has a minimum interrupt period of 16 ms, whereas the series regulated supply can have about 0.5 ms. Even this difference can be eliminated with a commutator circuit such as is being developed in Berkeley for the 150 kV, 20 ampere system. The 16 ms period is probably not a very serious limitation because it still permits up to 31 interrupts per 500 ms pulse. The shunt regulated system appears to be about 37 percent less expensive than the series system

  16. The evaluation of TE shunt operation in patients with high-dose irradiation

    Vocal rehabilitation of laryngectomized patients by means of TE shunt operation became popular in recent years. Since many of the candidates of this operation are heavily irradiated before the surgery, it appears important to evaluate the risk of the irradiation to such operation properly. In this communication, we report the retrospective evaluation of TE shunt operation performed in 16 patients who received 65 Gy or 40 Gy preoperatively. The surgical procedure used was mostly the modified Amatsu method. By this procedure, the duct as the inlet of the air was made by the tracheal wall containing cartilage rings, instead of the tracheal mucosa only. Minor wound complication occurred in 3 of 10 patients with 65 Gy irradiation but this did not ruin the shunt. Twelve patients (75 %) acquired satisfactory phonation after the surgery but 4 failed because of obstruction of the shunt. The aspiration inherent to this operation was generally acceptable, though 5 out of 16 patients (31 %) complained slight leakage of the fluid. Our results show that TE shunt operation is safe enough in those who received high-dose irradiation preoperatively. (author)

  17. Radionuclide cisternography in diagnostics of obstruction hydrocephalus in introduced ventricculoperitoneal shunt

    To confirm or exclude a diagnosis of internal obstruction hydrocephalus in an 8-year old girl with an introduced ventriculoperitoneal (V-P) shunt Establishing the V-P shunt is indisputably the route of choice in non-communicating hydrocephalus. The existence of a V-P shunt, however, is connected with numerous risks, especially of injuries, infection as well as increased intraabdominal pressure - e.g. in pregnancy. The development of endoscopy in neurosurgery allows the creation of communication via the bottom of the third ventricle with basal cisterns, and the subsequent cancellation of a V-P shunt. We describe the case of an 8-year old girl with congenital internal hydrocephalus with an assumed obliteration of the Sylvian aqueduct with an established V-P shunt. An MR scan described the membrane in the area of the Sylvian aqueduct, but the disproportion between the dilatation of the lateral ventricles, third ventricle and fourth ventricle led the physician to doubt as to the accuracy of the diagnosis of internal obstruction hydrocephalus. Therefore we performed a radionuclide cisternography (in a modified manner), which proved an existing communication between the third and fourth cerebral ventricle and which contradicted the clinical diagnosis of obstruction hydrocephalus. (author)

  18. Decompensated porto-pulmonary hypertension in a cirrhotic patient with thrombosis of portocaval shunt

    2007-01-01

    We report a case of decompensated porto-pulmonary hypertension closely associated with the development of intra-portocaval shunt thrombosis. A woman with Laennec's cirrhosis was hospitalized because of severe dyspnea and edema. She underwent surgical portocaval anastomosis ten years ago. Imaging studies showed massive intra-shunt thrombosis, portal hypertension, ascites, pleuro-pericardial effusions and enlargement of right cardiac cavities. Cardiac catheterization allowed to rule out coronary and leftsided heart abnormalities and led to the diagnosis of pre-capillary pulmonary hypertension. Antithrombotic treatment with low molecular weight heparin was instituted. The management also included ACE inhibitors,spironolactone, low-salt diet and lactulose. The patient was discharged and three months later we observed the disappearance of edema, ascites and pleuropericardial effusions, a marked body weight reduction and improved dyspnea and liver function tests. A possible link between the development of intra-shunt thrombosis and clinical decompensation in our patient was hypothesized. In fact, it has been demonstrated that the increased portal pressure, caused by occlusion of portosystemic shunt, reduces renal plasma flow and increases systemic endothelin-1 concentration. In our patient the disappearance of edematous state and improved dyspnea observed after recanalization of the shunt strongly support this hypothesis.

  19. Acute Pancreatitis and Pregnancy

    ... Acute Pancreatitis > Acute Pancreatitis and Pregnancy test Acute Pancreatitis and Pregnancy Timothy Gardner, MD Acute pancreatitis is ... of acute pancreatitis in pregnancy. Reasons for Acute Pancreatitis and Pregnancy While acute pancreatitis is responsible for ...

  20. Association of Genetic Polymorphisms of Renin–Angiotensin–Aldosterone System-Related Genes with Arterio-Venous Fistula Malfunction in Hemodialysis Patients

    Yu-Wei Chen

    2016-05-01

    Full Text Available Hemodialysis (HD is the most commonly-used renal replacement therapy for patients with end-stage renal disease worldwide. Arterio-venous fistula (AVF is the vascular access of choice for HD patients with lowest risk of infection and thrombosis. In addition to environmental factors, genetic factors may also contribute to malfunction of AVF. Previous studies have demonstrated the effect of genotype polymorphisms of angiotensin converting enzyme on vascular access malfunction. We conducted a multicenter, cross-sectional study to evaluate the association between genetic polymorphisms of renin-angiotensin-aldosterone system and AVF malfunction. Totally, 577 patients were enrolled. Their mean age was 60 years old and 53% were male. HD patients with AVF malfunction had longer duration of HD (92.5 ± 68.1 vs. 61.2 ± 51.9 months, p < 0.001, lower prevalence of hypertension (44.8% vs. 55.3%, p = 0.025, right-sided (31.8% vs. 18.4%, p = 0.002 and upper arm AVF (26.6% vs. 9.7%, p < 0.001, and higher mean dynamic venous pressure (DVP (147.8 ± 28.3 vs. 139.8 ± 30.0, p = 0.021. In subgroup analysis of different genders, location of AVF and DVP remained significant clinical risk factors of AVF malfunction in univariate and multivariate binary logistic regression in female HD patients. Among male HD patients, univariate binary logistic regression analysis revealed that right-side AVF and upper arm location are two important clinical risk factors. In addition, two single nucleotide polymorphisms (SNPs, rs275653 (Odds ratio 1.90, p = 0.038 and rs1492099 (Odds ratio 2.29, p = 0.017 of angiotensin II receptor 1 (AGTR1, were associated with increased risk of AVF malfunction. After adjustment for age and other clinical factors, minor allele-containing genotype polymorphisms (AA and CA of rs1492099 still remained to be a significant risk factor of AVF malfunction (Odds ratio 3.63, p = 0.005. In conclusion, we demonstrated that rs1492099, a SNP of AGTR1 gene, could

  1. Association of Genetic Polymorphisms of Renin–Angiotensin–Aldosterone System-Related Genes with Arterio-Venous Fistula Malfunction in Hemodialysis Patients

    Chen, Yu-Wei; Wu, Yu-Te; Lin, Jhin-Shyaun; Yang, Wu-Chang; Hsu, Yung-Ho; Lee, Kuo-Hua; Ou, Shou-Ming; Chen, Yung-Tai; Shih, Chia-Jen; Lee, Pui-Ching; Chan, Chia-Hao; Chung, Ming-Yi; Lin, Chih-Ching

    2016-01-01

    Hemodialysis (HD) is the most commonly-used renal replacement therapy for patients with end-stage renal disease worldwide. Arterio-venous fistula (AVF) is the vascular access of choice for HD patients with lowest risk of infection and thrombosis. In addition to environmental factors, genetic factors may also contribute to malfunction of AVF. Previous studies have demonstrated the effect of genotype polymorphisms of angiotensin converting enzyme on vascular access malfunction. We conducted a multicenter, cross-sectional study to evaluate the association between genetic polymorphisms of renin-angiotensin-aldosterone system and AVF malfunction. Totally, 577 patients were enrolled. Their mean age was 60 years old and 53% were male. HD patients with AVF malfunction had longer duration of HD (92.5 ± 68.1 vs. 61.2 ± 51.9 months, p < 0.001), lower prevalence of hypertension (44.8% vs. 55.3%, p = 0.025), right-sided (31.8% vs. 18.4%, p = 0.002) and upper arm AVF (26.6% vs. 9.7%, p < 0.001), and higher mean dynamic venous pressure (DVP) (147.8 ± 28.3 vs. 139.8 ± 30.0, p = 0.021). In subgroup analysis of different genders, location of AVF and DVP remained significant clinical risk factors of AVF malfunction in univariate and multivariate binary logistic regression in female HD patients. Among male HD patients, univariate binary logistic regression analysis revealed that right-side AVF and upper arm location are two important clinical risk factors. In addition, two single nucleotide polymorphisms (SNPs), rs275653 (Odds ratio 1.90, p = 0.038) and rs1492099 (Odds ratio 2.29, p = 0.017) of angiotensin II receptor 1 (AGTR1), were associated with increased risk of AVF malfunction. After adjustment for age and other clinical factors, minor allele-containing genotype polymorphisms (AA and CA) of rs1492099 still remained to be a significant risk factor of AVF malfunction (Odds ratio 3.63, p = 0.005). In conclusion, we demonstrated that rs1492099, a SNP of AGTR1 gene, could be a

  2. Bronchitis - acute

    ... sharing features on this page, please enable JavaScript. Acute bronchitis is swelling and inflammation in the main passages ... present only for a short time. Causes When acute bronchitis occurs, it almost always comes after having a ...

  3. Bronchitis - acute

    Acute bronchitis is swelling and inflammation in the main passages that carry air to the lungs. The swelling narrows ... makes it harder to breathe. Another symptom of bronchitis is a cough. Acute means the symptoms have ...

  4. Acute Bronchitis

    Bronchitis is an inflammation of the bronchial tubes, the airways that carry air to your lungs. It ... chest tightness. There are two main types of bronchitis: acute and chronic. Most cases of acute bronchitis ...

  5. Effect of positive end-expiratory pressure on pulmonary shunt and dynamic compliance during abdominal surgery

    Spadaro, S.; Karbing, Dan Stieper; Mauri, T.;

    2016-01-01

    52 patients undergoing either laparotomy or laparoscopic surgery. Three levels of PEEP were applied in random order: (1) zero (ZEEP), (2) 5 cmH2O and (3) 10 cmH2O. Pulmonary shunt and ventilation/perfusion mismatch were assessed by the automatic lung parameter estimator system. RESULTS: Pulmonary......BACKGROUND: General anaesthesia decreases pulmonary compliance and increases pulmonary shunt due to the development of atelectasis. The presence of capnoperitoneum during laparoscopic surgery may further decrease functional residual capacity, promoting an increased amount of atelectasis compared...... of 10 cmH2O. Although laparoscopic surgery was associated with a lower pulmonary compliance, increasing levels of PEEP were able to ameliorate it in both groups. CONCLUSION: Both surgeries have similar negative effects on pulmonary shunt, while the presence of capnoperitoneum reduced only the...

  6. Cerebral venous thrombosis complicated by hemorrhagic infarction secondary to ventriculoperitoneal shunting.

    Son, Won-Soo; Park, Jaechan

    2010-10-01

    While a delayed intracerebral hemorrhage at the site of a ventricular catheter has occasionally been reported in literature, a delayed hemorrhage caused by venous infarction secondary to ventriculoperitoneal shunting has not been previously reported. In the present case, a 68-year-old woman underwent ventriculoperitoneal shunting through a frontal burr hole, and developed a hemorrhagic transformation of venous infarction on the second postoperative day. This massive venous infarction was caused by bipolar coagulation and occlusion of a large paramedian cortical vein in association with atresia of the rostral superior sagittal sinus. Thus, to eliminate the risk of postoperative venous infarction, technical precautions to avoid damaging surface vessels in a burr hole are required under loupe magnification in ventriculoperitoneal shunting. PMID:21113365

  7. Multimodality cardiac imaging of a double chambered right ventricle with intrapulmonary shunting: a case report

    Kha Lan-Chau

    2012-09-01

    Full Text Available Abstract Background Double chambered right ventricle (DCRV is a relatively rare congenital heart disease, characterized by the abnormal division of the right ventricle into a high-pressure inlet and low-pressure outlet by anomalous muscle bundles. Extra-cardiac right-to-left shunts may present with clinical symptoms in adulthood and should be sought in patients with previous cavo-pulmonary shunt procedures. Case presentation We report a case of DCRV in a 29 year old Caucasian male presenting in adulthood with a right-to-left shunt secondary to venous collaterals, following cavopulmonary anastomosis for congenital pulmonary atresia and hypoplastic right ventricle. Conclusion Multimodality cardiac imaging using echocardiography, cardiac CT, cardiac MRI and cardiac catheterization is often required for complete characterization of complex congenital heart anomalies in adulthood.

  8. The Study of Magnetic Flux Shunts Effects on the Leakage Reactance of Transformers via FEM

    Karim Abbaszadeh

    2010-09-01

    Full Text Available The influence of arrangement, dimensions, and magnetic permeability of the magnetic flux shunts on the flux distribution and leakage reactance of the power transformers is studied in this paper by using a finite elements method and a simple modeling approach. By using magneto-static analysis and finite element method, first the flux distribution in the 2D model of a core-type three phase power transformer and then using the magnetic stored energy method the leakage reactance of the transformer windings is calculated. By studying the different models including magnetic flux shunts, the effect of the arrangement, geometric dimensions as well as the magnetic permeability of the magnetic flux shunt on the leakage reactance of the transformer are studied and some interesting results are obtained. It is shown that the variation of these parameters in the transformer model has significant effects on the leakage reactance of the transformer.

  9. Influence of projecting electrodes on shunt impedance and flatness of 4-rod radiofrequency quadrupole cavity

    Due to its advantages at low frequency, a 4-rod radiofrequency quadrupole (RFQ) structure has been adopted for the RFQ cavity at the Institute of Modern Physics, Chinese Academy of Sciences, which works at 100 MHz and is used for the direct plasma injection scheme. After the beam dynamics design, the parameters of the stems of the cavity were optimized to obtain the maximum shunt impedance. The capacitance existing in the projecting electrodes will affect the properties of the cavity, therefore, the influence of the projecting electrodes should be taken into account. Their influence on shunt impedance and flatness of the 4-rod RFQ cavity was studied, and the results show that the influence on shunt impedance can be neglected but it can not be neglected on flatness. In addition, the length range of the electrodes was presented for good flatness. (authors)

  10. Post-Transjugular Intrahepatic Portosystemic Shunt Follow-Up and Management in the VIATORR Era.

    Ferral, Hector; Gomez-Reyes, Elisa; Fimmel, Claus J

    2016-03-01

    The transjugular intrahepatic portosystemic shunt (TIPS) is a non-selective portosystemic shunt created using endovascular techniques. The first TIPS was performed in Germany in 1988. The VIATORR self-expandable PTFE covered stent-graft (WL Gore, Flagstaff AZ) was approved by the FDA for a TIPS application in December of 2004. This stent-graft offers excellent shunt patency rates and it is possible that it has a beneficial effect on patient survival. Patient surveillance and post-procedural management have changed after the introduction of this stent-graft. This article presents the current management strategies that are followed at our Institution for patients who have undergone a TIPS procedure with a VIATORR stent graft including imaging follow-up, management of encephalopathy, medical management and nutritional aspects. PMID:26997092

  11. Acute pancreatitis

    Bo-Guang Fan; Åke Andrén-Sandberg

    2010-01-01

    Background : Acute pancreatitis continues to be a serious illness, and the patients with acute pancreatitis are at risk to develop different complications from ongoing pancreatic inflammation. Aims : The present review is to highlight the classification, treatment and prognosis of acute pancreatitis. Material & Methods : We reviewed the English-language literature (Medline) addressing pancreatitis. Results : Acute pancreatitis is frequently caused by gallstone disease or excess alcohol ingest...

  12. Acute pancreatitis

    Bo-Guang Fan; Åke Andrén-Sandberg

    2010-01-01

    Background: Acute pancreatitis continues to be a serious illness, and the patients with acute pancreatitis are at risk to develop different complications from ongoing pancreatic inflammation. Aims: The present review is to highlight the classification, treatment and prognosis of acute pancreatitis. Material & Methods: We reviewed the English-language literature (Medline) addressing pancreatitis. Results: Acute pancreatitis is frequently caused by gallstone disease or excess alcohol ingestion....

  13. Deconvolution analysis in radionuclide quantitation at left-to-right cardiac shunts

    A poor bolus injection results in an unsatisfactory quantitative radionuclide angio-cardiogram in as many as 20% of chiledren with possible left-to-right (L-R) cardiac shunts. Deconvolution analysis was applied to similar studies in experimental animals to determine whether dependence on the input bolus could be minimized. Repeated good-bolus, prolonged (> 2.5 sec), or multiple-peak injections were made in four normal dogs and seven dogs with surgically created atrial septal defects (ASD). (QP/QS was determined using the gamma function. The mean (QP/QS from ten good-bolus studies in each animal was used as the standard for comparison. In five trials in normal animals, where a prolonged or double-peak bolus led to a shunt calculation QP/QS > 1.2:1), deconvolution resulted in QP/QS = 1.0. Deconvolution improved shunt quantitation in eight of ten trials in animals that received a prolonged bolus. The correlation between the reference QP/QS and the QP/QS calculated from uncorrected bad bolus studies was only 0.39 (p > 0.20). After deconvolution using a low pass filter, the correlation improved significantly (r = 0.77, p < 0.01). The technique gave inconsistent results with multiple-peak bolus injections. Deconvolution analysis in these studies is useful in preventing normals from being classified as shunts, and in improving shunt quantitation after a prolonged bolus. Clinical testing of this technique in children with suspected L-R shunts seems warranted

  14. Deconvolution analysis in radionuclide quantitation of left-to-right cardiac shunts.

    Alderson, P O; Douglass, K H; Mendenhall, K G; Guadiani, V A; Watson, D C; Links, J M; Wagner, H N

    1979-06-01

    A poor bolus injection results in an unsatisfactory quantitative radionuclide angiocardiogram in as many as 20% of children with possible, left-to-right (L-R) cardiac shunts. Deconvolution analysis was applied to similar studies in experimental animals to determine whether dependence on the input bolus could be minimized. Repeated good-bolus, prolonged (greater than 2.5 sec), or multiple-peak injections were made in four normal dogs and seven dogs with surgically created atrial septal defects (ASD). QP/QS was determined using the gamma function. The mean QP/QS from ten good-bolus studies in each animal was used as the standard for comparison. In five trials in normal animals, where a prolonged or double-peak bolus led to a shunt calculation (QP/QS greater than 1.2 : 1), deconvolution resulted in QP/QS = 1.0. Deconvolution improved shunt quantitation in eight of ten trials in animals that received a prolonged bolus. The correlation between the reference QP/QS and the QP/QS calculated from uncorrected bad bolus studies was only 0.39 (p greater than 0.20). After deconvolution using a low pass filter, the correlation improved significantly (r = 0.77, p less than 0.01). The technique gave inconsistent results with multiple-peak bolus injections. Deconvolution analysis in these studies is useful in preventing normals from being classified as shunts, and in improving shunt quantitation after a prolonged bolus. Clinical testing of this technique in children with suspected L-R shunts seems warranted. PMID:536823

  15. Robust glycogen shunt activity in astrocytes: Effects of glutamatergic and adrenergic agents.

    Walls, A B; Heimbürger, C M; Bouman, S D; Schousboe, A; Waagepetersen, H S

    2009-01-12

    The significance and functional roles of glycogen shunt activity in the brain are largely unknown. It represents the fraction of metabolized glucose that passes through glycogen molecules prior to entering the glycolytic pathway. The present study was aimed at elucidating this pathway in cultured astrocytes from mouse exposed to agents such as a high [K+], D-aspartate and norepinephrine (NE) known to affect energy metabolism in response to neurotransmission. Glycogen shunt activity was assessed employing [1,6-13C]glucose, and the glycogen phosphorylase inhibitor 1,4-dideoxy-1,4-imino-D-arabinitol (DAB) to block glycogen degradation. The label intensity in lactate, reflecting glycolytic activity, was determined by mass spectrometry. In the presence of NE a substantial glycogen shunt activity was observed, accounting for almost 40% of overall glucose metabolism. Moreover, when no metabolic stimulant was applied, a compensatory increase in glycolytic activity was seen when the shunt was inhibited by DAB. Actually the labeling in lactate exceeded that obtained when glycolysis and glycogen shunt both were operational, i.e. supercompensation. A similar phenomenon was seen when astrocytes were exposed to D-aspartate. In addition to glycolysis, tricarboxylic acid (TCA) cycle activity was monitored, analyzing labeling by mass spectrometry in glutamate which equilibrates with alpha-ketoglutarate. Both an elevated [K+] and D-aspartate induced an increased TCA cycle activity, which was altered when glycogen degradation was inhibited. Thus, the present study provides evidence that manipulation of glycogen metabolism affects both glycolysis and TCA cycle metabolism. Altogether, the results reveal a highly complex interaction between glycogenolysis and glycolysis, with the glycogen shunt playing a significant role in astrocytic energy metabolism. PMID:19000744

  16. Experimental study of an endothelial progenitor cell coated stent in transjugular intrahepatic portosystemic shunt

    Objective: To evaluate the efficacy of a self-expandable metal stent coated with autologous endothelial progenitor cells (EPCs) for prevention of restenosis in transjugular intrahepatic portosystemic shunt (TIPS) in a swine model. Methods: EPCs were coated on the metal stents using fibrin gel before TIPS procedure. TIPS was performed in 15 young adult pigs, using an autologous EPC-seeded stent (treatment group, n=9) or a conventional bare metal stent (control group, n=6). All pigs were sacrificed at 2 weeks after TIPS procedure. Portography was performed immediately before the euthanasia. Gross and microscopic pathological exams and immunohistochemical exams of the TIPS track specimens were performed. Fisher test and t test were used to analyse the data. Results: TIPS was performed successfully in all the 15 swine. On day 14 of follow-up, direct portography and necropsy demonstrated that 5 shunts remained patent, 2 shunts stenosed, and the remaining 2 shunts occluded in the treatment group (n=9); while 5 shunts were occluded and one shunt was stenotic in the control group (n=6). The patency rate was 56% vs 0 (P=0.03) between the two groups. Histological analyses showed a greater pseudo-intimal hyperplasia in the TIPS track of the control group than that of the treatment group (pseudointimal thickness at hepatic vein, hepatic parenchyma and portal vein site was (1.2±0.4), (1.3±0.5), (1.5±0.4) mm vs (1.0±0.6), (0.9±0.5), (1.0±0.4) mm respectively (P<0.05). Conclusion: The EPC-coated metal stent is feasibly constructed in vitro and improves the patency in TIPS in a porcine model. (authors)

  17. Erectile Function and Dysfunction Following Low Flow Priapism: A comparison of Distal and Proximal Shunts

    Ali Tabibi, ,

    2010-09-01

    Full Text Available PURPOSE: To compare erectile function following low flow priapism in patients undergoing distal and proximal shunts. MATERIALS AND METHODS: From January 1995 to December 2005, we retrospectively studied 16 patients who presented to our medical center with refractory priapism. Of 16 patients, 5 underwent Winter shunt, while El-Ghorab procedure was performed for 7 patients and the remaining 4 underwent Grayhack shunt. Erectile function was assessed in a minimum follow-up of 2 years (range, 2 to 10 years using erectile dysfunction (ED intensity scale [Total score: 5 to 10 (severe ED; 11 to 15 (moderate ED; 16 to 20 (mild ED; and 21 to 25 (no ED]. RESULTS: The mean patients’ age was 40.62 ± 15.27 years. Mean duration of priapism was 51.12 ± 37.99 hours. Of 4 patients (25% who underwent proximal shunt (Grayhack procedure, 2 (50% were impotent, 1 had potency, and the other one achieved some penile erection with administration of oral sildenafil. Of 5 patients (31.25% who underwent Winter procedure, 1 died because of metastatic bladder cancer and of 4 remainders, 2 (50% had normal erectile function, but 1 patient suffered from recurrent priapism. Of 7 patients (43.75% who underwent El-Ghorab procedure, 1 was lost for follow-up and of remaining 6 patients, 2 (33.3% had normal erectile function and 4 (66.6% were impotent. No surgical complication was seen. Median lag time from priapism till surgery for patients with and without ED was 48 and 26 hours, respectively (P = .22. CONCLUSION: Grayhack shunt is a safe surgical procedure without any major complications and with lower ED rate. Grayhack shunt might be considered as treatment of choice for refractory low flow priapism.

  18. Role of Mitochondria-rich Cells for Passive Chloride Transport, discussion of Ussing's Contribution to Our Understanding of Shunt Pathways in Epithelia

    Larsen, Erik Hviid; Kristensen, Poul; Nedergaard, Signe Nielsen;

    2001-01-01

    Toad skin, Mitochondria-rich cells, Chloride channels, Epithelial shunt pathways, Leaky epithelia, Recirculation theory of isotonic transport......Toad skin, Mitochondria-rich cells, Chloride channels, Epithelial shunt pathways, Leaky epithelia, Recirculation theory of isotonic transport...

  19. Radiation Exposure in Transjugular Intrahepatic Portosystemic Shunt Creation

    Miraglia, Roberto, E-mail: rmiraglia@ismett.edu; Maruzzelli, Luigi, E-mail: lmaruzzelli@ismett.edu; Cortis, Kelvin, E-mail: kelvincortis@ismett.edu [Mediterranean Institute for Transplantation and Advanced Specialized Therapies (ISMETT), Radiology Service, Department of Diagnostic and Therapeutic Services (Italy); D’Amico, Mario, E-mail: mdamico@ismett.edu [University of Palermo, Department of Radiology (Italy); Floridia, Gaetano, E-mail: gfloridia@ismett.edu; Gallo, Giuseppe, E-mail: ggallo@ismett.edu; Tafaro, Corrado, E-mail: ctafaro@ismett.edu; Luca, Angelo, E-mail: aluca@ismett.edu [Mediterranean Institute for Transplantation and Advanced Specialized Therapies (ISMETT), Radiology Service, Department of Diagnostic and Therapeutic Services (Italy)

    2016-02-15

    PurposeTransjugular intrahepatic portosystemic shunt (TIPS) creation is considered as being one of the most complex procedures in abdominal interventional radiology. Our aim was twofold: quantification of TIPS-related patient radiation exposure in our center and identification of factors leading to reduced radiation exposure.Materials and methodsThree hundred and forty seven consecutive patients underwent TIPS in our center between 2007 and 2014. Three main procedure categories were identified: Group I (n = 88)—fluoroscopic-guided portal vein targeting, procedure done in an image intensifier-based angiographic system (IIDS); Group II (n = 48)—ultrasound-guided portal vein puncture, procedure done in an IIDS; and Group III (n = 211)—ultrasound-guided portal vein puncture, procedure done in a flat panel detector-based system (FPDS). Radiation exposure (dose-area product [DAP], in Gy cm{sup 2} and fluoroscopy time [FT] in minutes) was retrospectively analyzed.ResultsDAP was significantly higher in Group I (mean ± SD 360 ± 298; median 287; 75th percentile 389 Gy cm{sup 2}) as compared to Group II (217 ± 130; 178; 276 Gy cm{sup 2}; p = 0.002) and Group III (129 ± 117; 70; 150 Gy cm{sup 2}p < 0.001). The difference in DAP between Groups II and III was also significant (p < 0.001). Group I had significantly longer FT (25.78 ± 13.52 min) as compared to Group II (20.45 ± 10.87 min; p = 0.02) and Group III (19.76 ± 13.34; p < 0.001). FT was not significantly different between Groups II and III (p = 0.73).ConclusionsReal-time ultrasound-guided targeting of the portal venous system during TIPS creation results in a significantly lower radiation exposure and reduced FT. Further reduction in radiation exposure can be achieved through the use of modern angiographic units with FPDS.

  20. Radiation Exposure in Transjugular Intrahepatic Portosystemic Shunt Creation

    PurposeTransjugular intrahepatic portosystemic shunt (TIPS) creation is considered as being one of the most complex procedures in abdominal interventional radiology. Our aim was twofold: quantification of TIPS-related patient radiation exposure in our center and identification of factors leading to reduced radiation exposure.Materials and methodsThree hundred and forty seven consecutive patients underwent TIPS in our center between 2007 and 2014. Three main procedure categories were identified: Group I (n = 88)—fluoroscopic-guided portal vein targeting, procedure done in an image intensifier-based angiographic system (IIDS); Group II (n = 48)—ultrasound-guided portal vein puncture, procedure done in an IIDS; and Group III (n = 211)—ultrasound-guided portal vein puncture, procedure done in a flat panel detector-based system (FPDS). Radiation exposure (dose-area product [DAP], in Gy cm2 and fluoroscopy time [FT] in minutes) was retrospectively analyzed.ResultsDAP was significantly higher in Group I (mean ± SD 360 ± 298; median 287; 75th percentile 389 Gy cm2) as compared to Group II (217 ± 130; 178; 276 Gy cm2; p = 0.002) and Group III (129 ± 117; 70; 150 Gy cm2p < 0.001). The difference in DAP between Groups II and III was also significant (p < 0.001). Group I had significantly longer FT (25.78 ± 13.52 min) as compared to Group II (20.45 ± 10.87 min; p = 0.02) and Group III (19.76 ± 13.34; p < 0.001). FT was not significantly different between Groups II and III (p = 0.73).ConclusionsReal-time ultrasound-guided targeting of the portal venous system during TIPS creation results in a significantly lower radiation exposure and reduced FT. Further reduction in radiation exposure can be achieved through the use of modern angiographic units with FPDS

  1. Characteristics of Operator to Malfunctions of Multi-jointed Manipulator Arm during Maintenance and Decommissioning of Nuclear Facilities

    With a view to determine a safe speed the limit of a manipulator arm, several experiments was performed with a multi-jointed manipulator in maintenance and decommissioning tasks of nuclear facilities. Under the simulated emergency conditions, which were generated with random combinations of manipulator arm speed, failure probability and failure type, response characteristics of human operators to various malfunctions of a manipulator arm were measured in terms of reaction time, number of false alarm, and number of misses. This paper demonstrated that failure type, manipulator axes and manipulator arm speed has significant effects on human reaction time. As a whole the reaction time was slightly increased with manipulator arm speed, which is showed somewhat different pattern due to failure type. The reaction time to an axis acting on a workpiece directly, which could flex and extend, was fastest and much more its standard deviation was small. Various factors which may affect safe speed were also described.

  2. Quantification of regional cerebral blood flow in rats using an arteriovenous shunt and micro-PET

    Introduction: Measurement of regional cerebral blood flow (rCBF) in rodents can provide knowledge of pathophysiology of the cerebral circulation, but generally requires blood sampling for analysis during positron emission tomography (PET). We therefore tested the feasibility of using an arteriovenous (AV) shunt in rats for less invasive blood analysis. Methods: Six anesthetized rats received [15O]H2O and [15O]CO PET scans with their femoral artery and vein connected by an AV shunt, the activity within which was measured with a germanium ortho-oxysilicate scintillation detector. The [15O]H2O was intravenously injected either at a faster or slower injection rate, while animals were placed either with their head or heart centered in the gantry. The time–activity curve (TAC) from the AV shunt was compared with that from the cardiac ventricle in PET image. The rCBF values were calculated by a nonlinear least-square method using the dispersion-corrected AV-shunt TAC as an input. Results: The AV-shunt TAC had higher signal-to-noise ratio, but also had delay and dispersion compared with the image-derived TAC. The delay time between the AV-shunt TAC and image-based TAC ranged from 11 to 21 s, while the dispersion was estimated to be ∼5 s as a time constant of the dispersion model of exponential function, and both were properly corrected. In a steady-state condition of [15O]CO PET, the blood activity concentration by AV-shunt TAC was also comparable in height with the image-based TAC corrected for partial volume. Whole-brain CBF values measured by [15O]H2O were 0.37±0.04 (mean±S.D.) ml/g/min, partition coefficient was 0.73±0.04 ml/g, and the CBF varied in a linear relationship with partial pressure of carbon dioxide during each scan. Conclusions: The AV-shunt technique allows less invasive, quantitative and reproducible measurement of rCBF in [15O]H2O PET studies in rats than direct blood sampling and radioassay.

  3. Centerline Longitudinal Shunt Slot Excitation by Elliptic shaped single Ridge Waveguide

    Mehdi Moradian

    2011-07-01

    Full Text Available The Application of elliptic shaped ridge waveguide is presented for excitation of a centreline longitudinal shunt slot antenna. The proposed method is realized by adding elliptic shaped to the ridge of the single ridge waveguide. The elliptic shaped ridge is placed exactly under the longitudinal slot and the slot placed along centreline of the waveguide. It is shown that for a typical slot, the slot normalized conductance can be increased by increasing the elliptic shaped depth. The simulation results show that the proposed structure can be considered as a proper candidate for replacing the conventional longitudinal shunt slot.

  4. IDLING AND NATURAL POWER TRANSFER LOSS SAVING BY MEANS OF SHUNT REACTORS AND REACTIVE POWER SOURCES

    Patsiuk V.I

    2009-04-01

    Full Text Available The closed formulas for definition of the steady–state values of voltages, currents, active and reactive power in a line with the distributed and lumped constants are shown. The influence of the shunt reactors and reactive power sources in the form of capacitor banks on losses of idling with various wave lengths is investigated. For the half-wave transmissions line the optimal parameters (which allow increasing of the output during the natural-power transfer of the shunt reactors were obtained.

  5. Percutaneous Mesocaval Shunt Creation in a Patient with Chronic Portal and Superior Mesenteric Vein Thrombosis

    The creation of a transjugular intrahepatic portosystemic shunt (TIPS) is a critical procedure for the treatment of recurrent variceal bleeding and refractory ascites in the setting of portal hypertension. Chronic portal vein thrombosis remains a relative contraindication to conventional TIPS and options are limited in this scenario. Presented is a novel technique for management of refractory ascites in a patient with hepatitis C cirrhosis and chronic portal and superior mesenteric vein thrombosis secondary to schistosomiasis and lupus anticoagulant utilizing fluoroscopically guided percutaneous mesocaval shunt creation

  6. A new method for palliation of malignant obstructive jaundice utilizing a peritoneo-venous shunt pump.

    Araki, K; Kure, M; Kobayasi, M; Sugito, M; Ogata, T

    1994-02-01

    A new simple palliative method for use in malignant obstructive jaundice is presented. This method is particularly effective in the prevention of ascending infections. The method consists of interposing a one-way flow shunt pump (peritoneo-venous shunt pump) between a bile catheter and a jejunal catheter. Four patients were treated with this new method. Jaundice improved significantly in all patients. They had a much better quality of life with no serious complications during the terminal course. This less invasive and safe procedure is preferred for patients who have extrahepatic biliary obstruction due to incurable malignant tumors. PMID:7513676

  7. Unusual cause for ventriculoperitoneal shunt failure: Carcinoma breast compressing distal catheter

    Roka Yam

    2010-01-01

    Full Text Available Insertion of a ventriculoperitoneal (VP shunt is one of the most common surgical procedures in any neurosurgery unit worldwide. Distal catheter obstruction outside the peritoneum is a rare cause of shunt failure. We report the first case of distal obstruction in a 70-year old female by carcinoma breast engulfing the catheter and causing kinking. Intraoperatively, the catheter was intratumoral with no flow of cerebrospinal fluid distally. She underwent relocation of a new catheter to the opposite side of the abdomen and modified mastectomy with resolution of the hydrocephalus. The postoperative course has been uneventful.

  8. Is it worth closing the atrial septal defect in patients with insignificant shunt?

    Komar, Monika; Przewłocki, Tadeusz; Olszowska, Maria; Sobień, Bartosz; Tomkiewicz-Pająk, Lidia; Podolec, Piotr

    2014-01-01

    Introduction Closure of the atrial septal defect in patients with insignificant shunt is controversial. Aim To evaluate the outcomes of transcatheter closure of atrial septal defect (ASD) in symptomatic patients with borderline shunt. Material and methods One hundred and sixty patients (120 female, 40 male) with a mean age of 30.1 ±16.2 (20–52) years with a small ASD who underwent transcatheter closure were analyzed. All patients had a small ASD with Qp: Qs ratio ≤ 1.5, mean 1.2 ±0.9 (1.1–1.5...

  9. Theoretical study of a shunt reactor subsynchronous resonance stabilizer for a nuclear powered generator

    The results of a theoretical investigation into the suppression of subsynchronous resonance (SSR) instability of a nuclear powered turbogenerator by using a signal derived from the generator speed to modulate the reactance of a shunt reactor situated at the generator terminals is presented. The analysis and design of such a shunt reactance controller are carried out by considering the full two-axis representation of the generator and network. Predicted results are presented to illustrate the ability of this controller to suppress subsynchronous resonance even when the system is subjected to severe large disturbances. (Auth.)

  10. Non-invasive assessment of shunt and ventilation/perfusion ratio in neonates with pulmonary failure

    H. Smith; Jones, J.

    2001-01-01

    AIMS—To make non-invasive measurements of right to left (R-L) shunt and reduced ventilation/perfusion ratio (VA/Q) in neonates with pulmonary failure and to examine sequential changes in these variables after treatment.
METHODS—Twelve neonates with pulmonary failure were studied. They ranged in gestational age from 24 to 37 (median 27) weeks and were 1-39 (median 4) days old. Shunt and reduced VA/Q were derived from their effects on the relation between inspired oxygen...

  11. A new class of weighting functions: Energy resolution improvement from an input shunt inductor

    A new class of optimum weighting functions is described, yielding optimum noise performances with a shunt inductance in the input circuit. Such an inductance is inherently present when transformer coupling is employed between the detector and the active device at the preamplifier input. The optimum weighting functions turn out to be area-balanced; they yield always less noise then optimum area-balanced functions optimized for input circuits without shunt inductance. The effects of the finite quality factor Q of the inductor are finally dealth with. (orig.)

  12. Percutaneous Mesocaval Shunt Creation in a Patient with Chronic Portal and Superior Mesenteric Vein Thrombosis

    Bercu, Zachary L., E-mail: zachary.bercu@mountsinai.org; Sheth, Sachin B., E-mail: sachinsheth@gmail.com [Icahn School of Medicine at Mount Sinai, Division of Interventional Radiology (United States); Noor, Amir, E-mail: amir.noor@gmail.com [The George Washington University School of Medicine and Health Sciences (United States); Lookstein, Robert A., E-mail: robert.lookstein@mountsinai.org; Fischman, Aaron M., E-mail: aaron.fischman@mountsinai.org; Nowakowski, F. Scott, E-mail: scott.nowakowski@mountsinai.org; Kim, Edward, E-mail: edward.kim@mountsinai.org; Patel, Rahul S., E-mail: rahul.patel@mountsinai.org [Icahn School of Medicine at Mount Sinai, Division of Interventional Radiology (United States)

    2015-10-15

    The creation of a transjugular intrahepatic portosystemic shunt (TIPS) is a critical procedure for the treatment of recurrent variceal bleeding and refractory ascites in the setting of portal hypertension. Chronic portal vein thrombosis remains a relative contraindication to conventional TIPS and options are limited in this scenario. Presented is a novel technique for management of refractory ascites in a patient with hepatitis C cirrhosis and chronic portal and superior mesenteric vein thrombosis secondary to schistosomiasis and lupus anticoagulant utilizing fluoroscopically guided percutaneous mesocaval shunt creation.

  13. Temporary axillary-carotid shunting for unusual instances of carotid stenosis.

    Shumacker, H B; Isch, J H; Jolly, W W

    1976-07-01

    A method has been developed which entails the introduction of the larger end of a Javid shunt tube in the axillary artery and the other in the internal carotid with only momentary interruption of blood flow. The method of closing the incision after the thromboendarterectomy almost entirely eliminates a second period of carotid occlusion. This procedure may be useful in unusual instances in which it is believed advantageous to avoid even the relatively short occlusion periods usually necessary when using the standard intraluminal shunt technique. PMID:936041

  14. Pancreaticoportal Fistula and Disseminated Fat Necrosis After Revision of a Transjugular Intrahepatic Portosystemic Shunt

    Klein, Seth J., E-mail: kleins@mir.wustl.edu; Saad, Nael [Washington University School of Medicine, Interventional Radiology Section, Mallinckrodt Institute of Radiology (United States); Korenblat, Kevin [Washington University School of Medicine, Division of Gastroenterology, Department of Internal Medicine (United States); Darcy, Michael D. [Washington University School of Medicine, Interventional Radiology Section, Mallinckrodt Institute of Radiology (United States)

    2013-04-15

    A 59-year old man with alcohol related cirrhosis and portal hypertension was referred for transjugular intrahepatic portosystemic shunt (TIPS) to treat his refractory ascites. Ten years later, two sequential TIPS revisions were performed for shunt stenosis and recurrent ascites. After these revisions, he returned with increased serum pancreatic enzyme levels and disseminated superficial fat necrosis; an iatrogenic pancreaticoportal vein fistula caused by disruption of the pancreatic duct was suspected. The bare area of the TIPS was subsequently lined with a covered stent-graft, and serum enzyme levels returned to baseline. In the interval follow-up period, the patient has clinically improved.

  15. Evaluation of Intrapulmonary Shunt Alterations at Different Oxygen Concentrations and Oxygenation Parameters

    Zerrin Demirtürk; Ecder Özenç; Sibel Buluç Bulğen

    2015-01-01

    Aim: The aim of the current study was to evaluate the relationship of intrapulmonary shunt with FiO2 alterations in patients treated with mechanical ventilation in intensive care unit for extrapulmonary disorders. Also, we aimed to assess the role of correlation between shunt ratio and PaO2/FiO2, PaO2/PAO2, P(A-a) O2 values in determining the treatment strategies. Methods: Twenty patients between ages of 19 and 75 years, requiring mechanical ventilation were enrolled into...

  16. Levoatriocardinal Vein: An Unusual Cause of Right-to-Left Shunting

    Nilima Shet

    2014-01-01

    Full Text Available We present a case demonstrating an anomalous vessel connecting the left brachiocephalic vein and the left superior pulmonary vein, found incidentally on computed tomography (CT imaging. This pulmonary-systemic venous connection, known as a levoatriocardinal vein, is a rare anomaly. In previous descriptions, this vessel has typically been associated with left-to-right shunt. Here, we describe the magnetic resonance imaging (MRI and CT findings in a case with right-to-left shunting through the anomalous vessel likely secondary to elevated right cardiac pressure.

  17. Performance of organics and nitrogen removal in subsurface wastewater infiltration systems by intermittent aeration and shunt distributing wastewater.

    Pan, Jing; Yuan, Fang; Yu, Long; Huang, Linli; Fei, Hexin; Cheng, Fan; Zhang, Qi

    2016-07-01

    Organics and nitrogen removal in four subsurface wastewater infiltration systems (SWISs), named SWIS A (without intermittent aeration and shunt distributing wastewater), SWIS B (with intermittent aeration), SWIS C (with shunt distributing wastewater) and SWIS D (with intermittent aeration and shunt distributing wastewater) was investigated. High average removal rates of 92.3% for COD, 90.2% for NH4-N and 88.1% for TN were achieved simultaneously in SWIS D compared with SWIS A, B and C. The excellent TN removal of SWIS D was due to intermittent aeration provided sufficient oxygen for nitrification in upper matrix and the favorable anoxic or anaerobic environment for denitrification in subsequent matrix, and moreover, shunt distributing wastewater provided sufficient carbon source for denitrification process. The results indicated that intermittent artificial aeration combined with shunt distributing wastewater could achieve high organics and nitrogen removal in SWISs. PMID:27039353

  18. Acute pancreatitis

    Bo-Guang Fan

    2010-05-01

    Full Text Available Background: Acute pancreatitis continues to be a serious illness, and the patients with acute pancreatitis are at risk to develop different complications from ongoing pancreatic inflammation. Aims: The present review is to highlight the classification, treatment and prognosis of acute pancreatitis. Material & Methods: We reviewed the English-language literature (Medline addressing pancreatitis. Results: Acute pancreatitis is frequently caused by gallstone disease or excess alcohol ingestion. There are a number of important issues regarding clinical highlights in the classification, treatment and prognosis of acute pancreatitis, and treatment options for complications of acute pancreatitis including pancreatic pseudocysts. Conclusions: Multidisciplinary approach should be used for the management of the patient with acute pancreatitis.

  19. Acute pancreatitis

    Bo-Guang Fan

    2010-01-01

    Full Text Available Background : Acute pancreatitis continues to be a serious illness, and the patients with acute pancreatitis are at risk to develop different complications from ongoing pancreatic inflammation. Aims : The present review is to highlight the classification, treatment and prognosis of acute pancreatitis. Material & Methods : We reviewed the English-language literature (Medline addressing pancreatitis. Results : Acute pancreatitis is frequently caused by gallstone disease or excess alcohol ingestion. There are a number of important issues regarding clinical highlights in the classification, treatment and prognosis of acute pancreatitis, and treatment options for complications of acute pancreatitis including pancreatic pseudocysts. Conclusions : Multidisciplinary approach should be used for the management of the patient with acute pancreatitis.

  20. Balanced calibration of resonant piezoelectric RL shunts with quasi-static background flexibility correction

    Høgsberg, Jan Becker; Krenk, Steen

    2015-01-01

    Resonant RL shunt circuits constitute a robust approach to piezoelectric damping, where the performance with respect to damping of flexible structures requires a precise calibration of the corresponding circuit components. The balanced calibration procedure of the present paper is based on equal...

  1. Significance of the site of injection in unexpected right-to-left shunting

    Lung perfusion scintigraphy, with Tc-99m MAA injected into a left antecubital vein, revealed extensive uptake in the myocardium, kidneys, spleen, thyroid, and brain. After a right antecubital injection, a normal pulmonary perfusion pattern was found. This finding is specific for right-to-left shunting due to anomalous systemic venous drainage into the left atrium

  2. A high incidence of spontaneous splenorenal shunting shown by digital splenoportography

    The technique of digital splenoportography with thin flexible needles and small amounts of dilute contrast medium is described as one particularly suitable for use in paediatric patients. The authors report a high incidence of spontaneous splenorenal shunting revealed in their patients by this technique. (orig.)

  3. Existence of Periodic Solutions for Shunting Inhibitory Cellular Neural Networks with Neutral Delays

    Ninghua Chen

    2013-01-01

    Full Text Available This paper considers the existence of periodic solutions for shunting inhibitory cellular neural networks (SICNNs with neutral delays. By applying the theory of abstract continuation theorem of k-set contractive operator and some analysis technique, a new result on the existence of periodic solutions is obtained.

  4. Existence of Periodic Solutions for Shunting Inhibitory Cellular Neural Networks with Neutral Delays

    Ninghua Chen

    2013-01-01

    This paper considers the existence of periodic solutions for shunting inhibitory cellular neural networks (SICNNs) with neutral delays. By applying the theory of abstract continuation theorem of k-set contractive operator and some analysis technique, a new result on the existence of periodic solutions is obtained.

  5. [Isolated left ventricular--right atrial shunt after blunt chest trauma (author's transl)].

    Kreuzer, E; Beyer, J

    1978-12-01

    A case of left-ventricular-right-atrial septal defect secundary to blunt chest trauma is described. The etiology of this type of septal defect, e. g. congenital, following aortic and mitral valve replacement, endocarditis and trauma, is discussed. Early defect closure is recommended in the presence of significant shunt volume. PMID:751280

  6. [Peritoneojugular shunt in the treatment of idiopathic ascites in the hemodialyzed patient: a clinical case].

    Massari, R; Marinelli, S; Fulgente, R; Summa, R

    1995-01-01

    The case of an uremic patient receiving dialytic treatment, who also had an hydiopatic ascites, probably due to peritoneal hyper-waterproofing, is described. Peritoneo-venous shunt was positioned with good result. Generally, similar clinical situations such a therapy is as valid as other commonly used methods. PMID:8706186

  7. AB227. Our experience of T-shaped shunt for the treatment of ischemic priapism

    Tang, Yuxin; Tan, Zhengyu; Zhou, Jun; Peng, Dongyi; Gan, Yu; Yang, Jianfu; He, Leye; Wang, Yong

    2016-01-01

    Objective To explore the efficacy of T-shaped shunt operation for the treatment of ischemic priapism. Methods We retrospectively studied nine patients with ischemic priapism. All patients were given preoperative MRI examination, T-shaped shunt operation and heparin saline flushing were performed when conservative therapy failed, a wedge biopsy of corpus cavernosum were done during the operation for tissue diagnosis. Results All patients had satisfactory outcome of the T-shaped shunt surgery except two patients who were diagnosed as malignant priapism, one was due to perineal neuroendocrine carcinoma and he refused taking further therapy and died 3 months later; the other was caused by penile epithelioid sarcoma and then accepted partial resection of penis; during 6–12 months follow-up, five cases developed erectile dysfunction. Conclusions MRI appears to be valuable for the management of ischemic priapism. Although T-shaped shunt operation has advantages of simple operation, less complications and satisfactory efficacy, it is not suitable for the patient of ischemic priapism which is caused by tumor. A wedge biopsy of corpus cavernosum during operation is helpful to confirm malignant priapism.

  8. Noncirrhotic Portal Hypertension due to Nodular Regenerative Hyperplasia Treated with Surgical Portacaval Shunt

    Lisa M. Louwers

    2012-01-01

    Full Text Available Nodular regenerative hyperplasia (NRH is an uncommon condition, but an important cause of noncirrhotic intrahepatic portal hypertension (NCIPH, characterized by micronodules of regenerative hepatocytes throughout the liver without intervening fibrous septae. Herein, we present a case of a thirty-seven-year-old female with systemic lupus erythematosus (SLE who was discovered to have significant esophageal varices on endoscopy for dyspepsia. Her labs revealed a slight elevation in the alkaline phosphatase and mild thrombocytopenia. Abdominal MRI revealed seven focal hepatic masses, splenomegaly, no ascites, and a patent portal vein. Ultrasound-guided core biopsy was reported as focal nodular hyperplasia. However, her varices persisted despite treatment with beta-blockers and four additional upper endoscopies with banding. She was subsequently referred for a surgical opinion. At that time, given her history of SLE, azathioprine use, and portal hypertension, suspicion for NRH was raised. Given her normal synthetic function and lack of parenchymal liver disease, the patient was offered surgical shunting. During shunt surgery, a liver wedge biopsy was also performed and this confirmed NRH. An upper endoscopy six weeks after shunting verified complete resolution of varices. Currently, fifteen months after surgery duplex ultrasonography demonstrates shunt patency and the patient is without recurrence of her portal hypertension.

  9. Percutaneous arteriovenous shunting in patients with severe COPD. A new interventional radiological treatment

    Purpose: The aim of this study was to evaluate the technical feasibility and safety of a new interventional radiological technique to create a shunt percutanously between the external iliac vein and artery in patients with severe COPD. Materials and Methods: 40 patients were included in this multicenter trial. In 38 patients the artery was punctured from the vein using a novel crossing needle. A special delivery system was used to implant a novel nitinol device (ACS, ROX Medical) between the artery and the vein to maintain a 4 mm calibrated and structured fistula between the two vessels. Results: Shunt implantation was successful in 38 patients. The perfused arteriovenous shunts could be well documented in DSA and the diameter was measured between 3 and 4 mm in all cases. Peri-interventional non-flow-limiting dissection of the iliac artery occurred in one patient. Post-interventional venous bleeding in two patients was treated successfully by local compression. In one patient a peripheral artery thrombembolism was successfully treated by thrombolysis. Conclusion: The new interventional radiological technique to create an arteriovenous shunt in the iliac vessels presented in this study has proven to be feasible and safe. (orig.)

  10. Biocompatibility of a novel tissue connector for fixation of tracheostoma valves and shunt valves

    Geertsema, AA; Schutte, HK; van Leeuwen, MBM; Rakhorst, G; Schakenraad, JM; van Luyn, MJA; Verkerke, GJ

    1999-01-01

    Rehabilitation after laryngectomy often includes the use of a shunt valve and a tracheostoma valve to restore voice. To improve the fixation method of these valves, a new tissue connector has been developed, basically consisting of a ring that will be integrated into surrounding tracheal soft tissue

  11. Experimental results of the tracheoesophageal tissue connector for improved fixation of shunt valves in laryngectomized patients

    ten Hallers, E. J. Olivier; Marres, Henri A. M.; van der Houwen, Eduard B.; Jansen, John A.; Rakhorst, Gerhard; Schutte, Harm K.; van Kooten, Theo G.; van Loon, Jan-Paul; Verkerke, Gijsbertus J.

    2006-01-01

    Background, After total laryngectomy and voice rehabilitation using a tracheoesophageal shunt valve, patients often have valve-related complications such as leakage. To solve these problems, a tracheoesophageal tissue connector (TE-TC) was devised to serve as an interface between the patient's tissu

  12. Negative capacitance shunt damping system with optimized characteristics for use with piezoelectric transducers

    Pohl, Martin

    2014-03-01

    For ecologic sustainability and decreasing reserves of fossile energy sources, fuel efficiency is a major concern especially for passenger aircraft. Therefore, lightweight structures made from carbon fiber plastics offer great potential. But when used for panel-like structures, they have the disadvantage of lower damping and coincidence frequencies compared to conventional differential metal constructions. Both aspects lead to an increased vibration level and by this a higher noise radiation. Because of this, special noise and vibration treatment is needed to ensure passenger cabin comfort. Besides passive damping and active structural acoustic control (ASAC), piezoelectric shunt damping is investigated. Due to its broadband performance, the negative capacitance shunt can be used for multimode systems with varying eigenfrequencies. These shunts are usually built with operational amplifiers and passive components as resistors and capacitors. This setup is sufficient for laboratory tests at low excitation levels. In fact, it is not capable of accessing the full voltage amplitude of common piezoelectric transducers, because most operational amplifiers only deliver +/-15V maximum output voltage. Therefore an improved setup is presented in this paper, which addresses the specific voltage requirements of a common piezoelectric transducer to achieve best performance. It comprises a tailored power source and an appropriate concept for the negative capacitance shunt hardware. This new hardware only uses standard operational amplifiers together with a high voltage power amplifier to cover the whole operating range of a piezoelectric transducer. A demonstrator board is developed and experimentally investigated at a test structure. Finally, the results are compared to a conventional setup.

  13. Periodic shunted arrays for the control of noise radiation in an enclosure

    Casadei, Filippo; Dozio, Lorenzo; Ruzzene, Massimo; Cunefare, Kenneth A.

    2010-08-01

    This work presents numerical and experimental investigations of the application of a periodic array of resistive-inductive (RL) shunted piezoelectric patches for the attenuation of broadband noise radiated by a flexible plate in an enclosed cavity. A 4×4 lay-out of piezoelectric patches is bonded to the surface of a rectangular plate fully clamped to the top face of a rectangular cavity. Each piezo-patch is shunted through a single RL circuit, and all shunting circuits are tuned at the same frequency. The response of the resulting periodic structure is characterized by frequency bandgaps where vibrations and associated noise are strongly attenuated. The location and extent of induced bandgaps are predicted by the application of Bloch theorem on a unit cell of the periodic assembly, and they are controlled by proper selection of the shunting circuit impedance. A coupled piezo-structural-acoustic finite element model is developed to evaluate the noise reduction performance. Strong attenuation of multiple panel-controlled modes is observed over broad frequency bands. The proposed concept is tested on an aluminum plate mounted in a wooden box and driven by a shaker. Experimental results are presented in terms of pressure responses recorded using a grid of microphones placed inside the acoustic box.

  14. Cerebrospinal fluid markers before and after shunting in patients with secondary and idiopathic normal pressure hydrocephalus

    Tisell Magnus

    2008-04-01

    Full Text Available Abstract Background The aim of this study was to explore biochemical changes in the cerebrospinal fluid (CSF induced by shunt surgery and the relationship between these changes and clinical improvement. Methods We measured clinical symptoms and analysed lumbar CSF for protein content, neurodegeneration and neurotransmission markers in patients with secondary (SNPH, n = 17 and idiopathic NPH (INPH, n = 18 before and 3 months after shunt surgery. Patients were divided into groups according to whether or not there was improvement in clinical symptoms after surgery. Results Preoperatively, the only pathological findings were elevated neurofilament protein (NFL, significantly more so in the SNPH patients than in the INPH patients, and elevated albumin content. Higher levels of NFL correlated with worse gait, balance, wakefulness and neuropsychological performance. Preoperatively, no differences were seen in any of the CSF biomarkers between patients that improved after surgery and those that did not improve. Postoperatively, a greater improvement in gait and balance performance correlated with a more pronounced reduction in NFL. Levels of albumin, albumin ratio, neuropeptide Y, vasoactive intestinal peptide and ganglioside GD3 increased significantly after shunting in both groups. In addition, Gamma amino butyric acid increased significantly in SNPH and tau in INPH. Conclusion We conclude that a number of biochemical changes occur after shunt surgery, but there are no marked differences between the SNPH and INPH patients. The results indicate that NFL may be a marker that can predict a surgically reversible state in NPH.

  15. Bilateral Fetal Hydrothorax Requiring Intrauterine Fetal Thoracoamniotic Shunts: Anesthetic Considerations and Management

    Hache, John J.; Emery, Stephen P.; Vallejo, Manuel C.

    2009-01-01

    After prenatal diagnosis of bilateral fetal hydrothorax, ascites, and polyhydramnios, bilateral thoracoamniotic shunts were placed at 29 weeks gestation using an ultrasound-guided, minimally invasive technique. Anesthetic care was managed using intravenous sedation and local anesthesia infiltration. The anesthetic considerations for such procedures are discussed.

  16. Bilateral Fetal Hydrothorax Requiring Intrauterine Fetal Thoracoamniotic Shunts: Anesthetic Considerations and Management

    John J. Hache

    2009-01-01

    Full Text Available After prenatal diagnosis of bilateral fetal hydrothorax, ascites, and polyhydramnios, bilateral thoracoamniotic shunts were placed at 29 weeks gestation using an ultrasound-guided, minimally invasive technique. Anesthetic care was managed using intravenous sedation and local anesthesia infiltration. The anesthetic considerations for such procedures are discussed.

  17. Alteration of brain viscoelasticity after shunt treatment in normal pressure hydrocephalus

    Freimann, Florian Baptist; Sprung, Christian [Charite - University Medicine Berlin, Campus Virchow-Klinikum, Neurosurgical Department, Berlin (Germany); Streitberger, Kaspar-Josche; Klatt, Dieter; Sack, Ingolf [Charite - University Medicine Berlin, Campus Charite Mitte, Department of Radiology, Berlin (Germany); Lin, Kui; McLaughlin, Joyce [Rensselaer Polytechnic Institute, Mathematics Department, Troy, NY (United States); Braun, Juergen [Charite - University Medicine Campus Benjamin Franklin, Institute of Medical Informatics, Berlin (Germany)

    2012-03-15

    Normal pressure hydrocephalus (NPH) represents a chronic neurological disorder with increasing incidence. The symptoms of NPH may be relieved by surgically implanting a ventriculoperitoneal shunt to drain excess cerebrospinal fluid. However, the pathogenesis of NPH is not yet fully elucidated, and the clinical response of shunt treatment is hard to predict. According to current theories of NPH, altered mechanical properties of brain tissue seem to play an important role. Magnetic resonance elastography (MRE) is a unique method for measuring in vivo brain mechanics. In this study cerebral MRE was applied to test the viscoelastic properties of the brain in 20 patients with primary (N = 14) and secondary (N = 6) NPH prior and after (91 {+-} 16 days) shunt placement. Viscoelastic parameters were derived from the complex modulus according to the rheological springpot model. This model provided two independent parameters {mu} and {alpha}, related to the inherent rigidity and topology of the mechanical network of brain tissue. The viscoelastic parameters {mu} and {alpha} were found to be decreased with -25% and -10%, respectively, compared to age-matched controls (P < 0.001). Interestingly, {alpha} increased after shunt placement (P < 0.001) to almost normal values whereas {mu} remained symptomatically low. The results indicate the fundamental role of altered viscoelastic properties of brain tissue during disease progression and tissue repair in NPH. Clinical improvement in NPH is associated with an increasing complexity of the mechanical network whose inherent strength, however, remains degraded. (orig.)

  18. Catheterobronchial fistula due to vena cava superior thrombosis as a late complication of ventriculoatrial shunt.

    Parízek, J; Nytra, T; Zemánková, M; Eliás, P; Sercl, M; Nĕmecková, J; Jakubec, J

    1994-09-01

    A case of a catheterobronchial fistula as a rare late complication of a ventriculoatrial shunt is reported. The ventriculoatrial shunt was implanted in a 4-month-old boy suffering from extreme postinfectious hydrocephalus. During the following years, twelfth nerve palsy on the right, vertebralgias, and salty taste sensations in the mouth associated with intermittent coughing and swelling of the neck and supraclavicular region on the right side developed. Valvography established a diagnosis of fistula 12 years after the implantation of a shunt. Ultrasonography of the neck and mediastinum and contrast-enhanced dynamic computed tomographic scanning demonstrated a catheterobronchial fistula to the subsegmental bronchus of the anterior segment of the right upper lung lobe, a thrombosis of the right internal jugular and both right and left brachiocephalic veins and the superior vena cava, and an extensive collateral venous system mainly draining into the azygos vein. Normalization of cerebrospinal fluid and blood flow and pressure allowed extraction of the "atrial" catheter without complications. One year after surgery the boys is in good health and without signs of shunt dependence. PMID:7842439

  19. A Multi-Mode Blade Damping Control using Shunted Piezoelectric Transducers with Active Feedback Structure

    Choi, Benjamin; Morrison, Carlos; Min, James

    2009-01-01

    The Structural Dynamics and. Mechanics branch (RXS) is developing smart adaptive structures to improve fan blade damping at resonances using piezoelectric (PE) transducers. In this presentation, only one shunted PE transducer was used to demonstrate active control of multi-mode blade resonance damping on a titanium alloy (Ti-6A1-4V) flat plate model, regardless of bending, torsion, and 2-stripe modes. This work would have a significant impact on the conventional passive shunt damping world because the standard feedback control design tools can now be used to design and implement electric shunt for vibration control. In other words, the passive shunt circuit components using massive inductors and. resistors for multi-mode resonance control can be replaced with digital codes. Furthermore, this active approach with multi patches can simultaneously control several modes in the engine operating range. Dr. Benjamin Choi presented the analytical and experimental results from this work at the Propulsion-Safety and. Affordable Readiness (P-SAR) Conference in March, 2009.

  20. Pictorial essay: trans-jugular intra-hepatic porto-systemic shunt (TIPS)

    TIPS is an interventional radiologic method of creating a portosystemic shunt by percutaneous means. It is a relatively new weapon in the armamentarium of the management of portal hypertension with variceal bleeding or intractable ascites. Using needles, angioplasty balloon catheters and expandable metallic stents, a shunt is established directly inside the liver parenchyma connecting a large hepatic vein with a main portal vein branch. Depending on the diameter of the expandable stent used, the created TIPS diverts various amounts of portal blood into the systemic circulation and results in significant portal decompression, cessation of hemorrhage from esophageal varices and resolution of ascites. TIPS is not only an effective and safe alternative to shunt surgery but is life saving in cases of variceal hemorrhage. The use of TIPS seems to be a valid alternative to surgery and has several advantages over either esophageal transection or surgical shunts. TIPS avoids a general anesthetic, laparotomy, and disruption of the hepatic venous system that may adversely affect subsequent hepatic transplantation. TIPS has been performed on patients without interfering with successful transplantation

  1. A method to prevent life-threatening intraperitoneal bleeding during transjugular intrahepatic portosystemic shunt creation

    To prevent intraperitoneal bleeding, it is critical that the extrahepatic portal vein should not be punctured during transjugular intrahepatic portosystemic shunt (TIPS). There has, however, been no procedure for defining the anatomic relationship between the hepatic capsule and the portal vein segment before shunt formation. To avoid a possibly catastrophic outcome of extrahepatic portal puncture before shunt creation, we therefore devised a new method; the purpose of this study is to report its efficacy and feasibility. whenever a portal vein was punctured, we advanced a 9 F sheath over a guidewire into the portal vein before balloon dilatation of the tract. Contrast material was then injected through the sheath as this was slowly extravasated or spilled into the peritoneal segment of the portal vein was punctured, and a shunt was created using this new tract. We applied this method to 130 consecutive patients who underwent TIPS to control variceable bleeding due to liver cirrhosis. In all cases, photography and ultrasonography were used for immediate confirmation of the procedure. For preventing intraperitoneal hemorrhage during TIPS creation, our method is effective and feasible. (author). 7 refs., 1 fig

  2. Lateral thoracotomy and cellophane banding of a congenital portoazygous shunt in a dog

    Portoazygous venous shunt was identified in the caudodorsal aspect of the thorax in a young basset hound. During thoracotomy, the anomalous vessel was encircled with sterile cellophane tape. The vein became occluded based on postoperative radiographic examination and improved clinical function five weeks after surgery

  3. Finite Element and Experimental Study of Shunting in Resistance Spot Welding

    Seyyedian Choobi, M.; Nielsen, C. V.; Bay, N.

    2015-01-01

    conducted to investigate the effect of shunting on nugget size in spot welding of HSLA steel sheets. Different cases with different spacing between weld spots have been examined. The nugget sizes have been measured by metallographic examination and have been compared with 3D finite element simulations. The...

  4. Bacterial contamination of surgeons' gloves during shunt insertion; a pilot study

    Sørensen, Preben; Ejlertsen, Tove; Aaen, Dorte;

    2008-01-01

    handling the shunt and completing the operation. The plates were cultured for 6 days in both aerobic and anaerobic environment. In all cases the surgeons gloves were contaminated, and in six cases also the nurses' gloves were contaminated, as well as all three assistants. Propionebacterium acnes were...

  5. Manipulating waves by distilling frequencies: a tunable shunt-enabled rainbow trap

    Cardella, Davide; Celli, Paolo; Gonella, Stefano

    2016-08-01

    In this work, we propose and test a strategy for tunable, broadband wave attenuation in electromechanical waveguides with shunted piezoelectric inclusions. Our strategy is built upon the vast pre-existing literature on vibration attenuation and bandgap generation in structures featuring periodic arrays of piezo patches, but distinguishes itself for several key features. First, we demystify the idea that periodicity is a requirement for wave attenuation and bandgap formation. We further embrace the idea of ‘organized disorder’ by tuning the circuits as to resonate at distinct neighboring frequencies. In doing so, we create a tunable ‘rainbow trap’ (Tsakmakidis et al 2007 Nature 450 397–401) capable of attenuating waves with broadband characteristics, by distilling (sequentially) seven frequencies from a traveling wavepacket. Finally, we devote considerable attention to the implications in terms of packet distortion of the spectral manipulation introduced by shunting. This work is also meant to serve as a didactic tool for those approaching the field of shunted piezoelectrics, and attempts to provide a different perspective, with abundant details, on how to successfully design an experimental setup involving resistive-inductive shunts.

  6. The C-shunt Flux Qubit: A New Generation of Superconducting Flux Qubit

    Birenbaum, Jeffrey Scott

    While quantum computation has the potential to revolutionize the scientific community, to date no architecture has been developed which offers the necessary combination of high coherence times and massive scalability. Superconducting flux qubits satisfy the second requirement well but to date useful devices are limited to coherence times of typically only a few mus. In this dissertation we examine the possibilities of improving the coherence performance of the flux qubit to the levels required for fault-tolerant quantum computation. We find that coherence times for many devices are limited by photon-induced quasiparticles and mitigation of these quasiparticles increases coherence times by more than a factor of two. Beyond this, however, we find little improvement in flux qubit performance compared to prior results. Despite improved fabrication techniques and varied device designs we find flux qubit coherence times are still typically below 5 mus. Furthermore, wide device-to-device variations are observed which prevent effective scaling of the flux qubit to quantum information circuits. Based on the proposal by You, et al. we develop of a capacitively-shunted version of the flux qubit called the C-shunt flux qubit. With the addition of a capacitive shunt across the small junction of the flux qubit we are able to reduce the amplitude sensitivity to both charge and flux noise by more than a factor of three. The result is a predicted ten-fold enhancement in the coherence times compared to the unshunted flux qubit. At the same time we preserve much of the anharmonicity of the flux qubit resulting in a device with coherence times comparable to modern transmons but with a factor of four better anharmonicity and more flexible coupling configurations. By using a high-quality MBE aluminum shunt process on an annealed sapphire substrate coupled with a more conventional electron-beam-evaporated aluminum Josephson junction process we fabricate hybrid C-shunt flux qubits. We

  7. Investigation of the hydrodynamic properties of a new MRI-resistant programmable hydrocephalus shunt

    Pickard John D

    2008-04-01

    Full Text Available Abstract Background The Polaris valve is a newly released hydrocephalus shunt that is designed to drain cerebrospinal fluid (CSF from the brain ventricles or lumbar CSF space. The aim of this study was to bench test the properties of the Polaris shunt, independently of the manufacturer. Methods The Polaris Valve is a ball-on-spring valve, which can be adjusted magnetically in vivo. A special mechanism is incorporated to prevent accidental re-adjustment by an external magnetic field. The performance and hydrodynamic properties of the valve were evaluated in the UK Shunt Evaluation Laboratory, Cambridge, UK. Results The three shunts tested showed good mechanical durability over the 3-month period of testing, and a stable hydrodynamic performance over 45 days. The pressure-flow performance curves, operating, opening and closing pressures were stable. The drainage rate of the shunt increased when a negative outlet pressure (siphoning was applied. The hydrodynamic parameters fell within the limits specified by the manufacturer and changed according to the five programmed performance levels. Hydrodynamic resistance was dependant on operating pressure, changing from low values of 1.6 mmHg/ml/min at the lowest level to 11.2 mmHg/ml/min at the highest performance level. External programming proved to be easy and reliable. Even very strong magnetic fields (3 Tesla were not able to change the programming of the valve. However, distortion of magnetic resonance images was present. Conclusion The Polaris Valve is a reliable, adjustable valve. Unlike other adjustable valves (except the Miethke ProGAV valve, the Polaris cannot be accidentally re-adjusted by an external magnetic field.

  8. Hepatopulmonary shunting in patients with primary and secondary liver tumors scheduled for radioembolization

    Purpose: In patients undergoing transarterial radioembolization (RE) of malignant liver tumors, hepatopulmonary shunts (HPS) can lead to nontarget irradiation of the lungs. This study aims at analyzing the HPS fraction in relation to liver volume, tumor volume, tumor-to-liver volume ratio, tumor vascularity, type of tumor, and portal vein occlusion. Materials and methods: In the presented retrospective study the percentage HPS fraction was calculated from SPECT/CT after infusion of Tc-99m macroaggregated albumin (Tc-99m MAA) into the proper hepatic artery of 233 patients evaluated for RE. Results: HPS fractions correlate very weakly with liver volume (r = 0.303), tumor volume (r = 0.345), and tumor-to-liver volume ratio (r = 0.340). Tumors with strong contrast enhancement (HPSmedian(range) = 11.7%(46.3%); n = 73) have significantly larger shunt fractions than tumors with little enhancement (HPS = 8.3%(16.4%); n = 61; p < 0.001). Colorectal cancer metastases (HPS = 10.6%(28.6%); n = 68) and hepatocellular cancers (HPS = 11.7%(39.4%); n = 63) have significantly larger HPS fractions than metastases from breast cancer (HPS = 7.4%(16.7%); n = 40; p = 0.012 and p = 0.001). Patients with compression (HPS = 13.9%(43.7%); n = 33) or tumor thrombosis (HPS = 15.8% (31.2%); n = 33) of a major portal vein branch have significantly higher degrees of shunting than patients with normal portal vein perfusion (HPS = 8.1% (47.0%); n = 167; both p < 0.001). The shunt fraction is largest in patients with HCC and thrombosis or occlusion of a major portal vein branch (HPS = 16.6% (31.0%); n = 32). Conclusion: The degree of hepatopulmonary shunting depends on the type of liver tumor, tumor vascularity, and portal vein perfusion. There is little to no correlation of HPS with liver volume, tumor volume, or tumor-to-liver volume ratio

  9. Indication for shunt operation of normal pressure hydrocephalus. Combined assessment of infusion test and dynamic CT scan

    Normal pressure hydrocephalus (NPH) is one of the diseases that causes a neuro-surgically treatable form of dementia. Although patients with NPH can be treated with shunt operation, reliable indications for the surgery are not yet established. In this study, 20 NPH patients diagnosed by clinical symptoms were subjected to combined assessment by infusion test and dynamic CT scan, a useful diagnostic tool to select a shunt responsive cases. Patients were evaluated by measuring sequential changes in the density of the periventricular lucency (PVL) using dynamic CT scan and continuous lumbar subdural pressure monitoring during an infusion manometric test at a rate of 0.8 ml/min for 30 min. The average lumbar subdural pressure during infusion manometric test in the shunt responsive group was 18.4±5.8 mmHg, which was significantly higher than that in the shunt non-responsive group which was 10.0±4.0 mmHg (p<0.01). The relative changes in PVL density in the dynamic CT was also significantly higher in the shunt responsive group (0.99±0.61 HU) compared to the shunt non-responsive group (0.15±0.32) (p<0.01). Dynamic CT scan with infusion manometric test is useful in the selection of patients with NPH who are likely to respond to shunt surgery. (author)

  10. Indication for shunt operation of normal pressure hydrocephalus. Combined assessment of infusion test and dynamic CT scan

    Jinnai, Takahiro; Nagao, Seigo [Kagawa Medical Univ., Miki (Japan); Kuyama, Hideyuki

    2000-03-01

    Normal pressure hydrocephalus (NPH) is one of the diseases that causes a neuro-surgically treatable form of dementia. Although patients with NPH can be treated with shunt operation, reliable indications for the surgery are not yet established. In this study, 20 NPH patients diagnosed by clinical symptoms were subjected to combined assessment by infusion test and dynamic CT scan, a useful diagnostic tool to select a shunt responsive cases. Patients were evaluated by measuring sequential changes in the density of the periventricular lucency (PVL) using dynamic CT scan and continuous lumbar subdural pressure monitoring during an infusion manometric test at a rate of 0.8 ml/min for 30 min. The average lumbar subdural pressure during infusion manometric test in the shunt responsive group was 18.4{+-}5.8 mmHg, which was significantly higher than that in the shunt non-responsive group which was 10.0{+-}4.0 mmHg (p<0.01). The relative changes in PVL density in the dynamic CT was also significantly higher in the shunt responsive group (0.99{+-}0.61 HU) compared to the shunt non-responsive group (0.15{+-}0.32) (p<0.01). Dynamic CT scan with infusion manometric test is useful in the selection of patients with NPH who are likely to respond to shunt surgery. (author)

  11. When do the symptoms of autonomic nervous system malfunction appear in patients with Parkinson’s disease?

    De Luka Silvio R.

    2014-01-01

    Full Text Available Background/Aim. Dysautonomia appears in almost all patients with Parkinson’s disease (PD in a certain stage of their condition. The aim of our study was to detect the development and type of autonomic disorders, find out the factors affecting their manifestation by analyzing the potential association with demographic variables related to clinical presentation, as well as the symptoms of the disease in a PD patient cohort. Methods. The patients with PD treated at the Clinic of Neurology in Belgrade during a 2-year period, divided into 3 groups were studied: 25 de novo patients, 25 patients already treated and had no long-term levodopa therapy-related complications and 22 patients treated with levodopa who manifested levodopa-induced motor complications. Simultaneously, 35 healthy control subjects, matched by age and sex, were also analyzed. Results. Autonomic nervous system malfunction was defined by Ewing diagnostic criteria. The tests, indicators of sympathetic and parasympathetic nervous systems, were significantly different in the PD patients as compared with the controls, suggesting the failure of both systems. However, it was shown, in the selected groups of patients, that the malfunction of both systems was present in two treated groups of PD patients, while de novo group manifested only sympathetic dysfunction. For this reason, the complete autonomic neuropathy was diagnosed only in the treated PD patients, while de novo patients were defined as those with the isolated sympathetic dysfunction. The patients with the complete autonomic neuropathy differed from the subjects without such neuropathy in higher cumulative and motor unified Parkinson’s disease rating score (UPDRS (p < 0.01, activities of daily living scores (p < 0.05, Schwab-England scale (p < 0.001 and Hoehn-Yahr scale. There was no difference between the patients in other clinical-demographic characteristics (sex, age at the time of diagnosis, actual age, duration of

  12. Acute respiratory failure after endoscopic third ventriculostomy: A case report and review of the literature

    Elgamal, Essam A.; Mansoor Aqil

    2012-01-01

    Endoscopic third ventriculostomy (ETV) is a relatively safe procedure. However, postoperative acute respiratory failure may be fatal. The authors report an 8-month-old patient with obstructive hydrocephalus secondary to posterior fossa cyst, and Chiari malformation. After ETV he developed difficulty in breathing, and had to be reintubated and ventilated. The infant recovered fully after craniocervical decompression and insertion of cystoperitoneal shunt. We speculate that respiratory failure ...

  13. Long Term Results (>5 Years) in Patients With Peritoneovenous Shunting for Intractable Ascites: Liver Function and Cancer Mortality

    Franco, Dominique; Meakins, Jonathan L.; Wu, Andrew; Smadja, Claude; Bonnet, Patrick; Gouffier, Etienne; Campillo, Bernard

    1989-01-01

    This report is based on twenty-eight (26%) of 107 patients included in a protocol for prospective evaluation of elective peritoneo-venous shunting for intractable ascites in cirrhosis. These patients had no other procedures and survived more than 5 years after the operation. All patients were free of ascites except one in whom it was mild. One patient refused follow-up. Shunt patency was assessed in 23 patients. In 14 patients (60.9%), the shunt was obstructed and the superior vena cava was o...

  14. Vascular plug-assisted retrograde transvenous obliteration of portosystemic shunts for refractory hepatic encephalopathy: a case report.

    Park, Jonathan K; Cho, Sung-Ki; Kee, Stephen; Lee, Edward W

    2014-01-01

    While balloon-assisted retrograde transvenous obliteration (BRTO) has been used for two decades in Asia for the management of gastric variceal bleeding, it is still an emerging therapy elsewhere. Given the shunt closure brought about by the procedure, BRTO has also been used for the management of portosystemic encephalopathy with promising results. Modified versions of BRTO have been developed, including plug-assisted retrograde transvenous obliteration (PARTO), where a vascular plug is deployed within a portosystemic shunt. To our knowledge, we present the first North American case of PARTO in the setting of a large splenorenal shunt for the management of portosystemic encephalopathy. PMID:24744943

  15. Field Experiments on 10 kV Switching Shunt Capacitor Banks Using Ordinary and Phase-Controlled Vacuum Circuit Breakers

    Wenxia Sima; Mi Zou; Qing Yang; Ming Yang; Licheng Li

    2016-01-01

    During the switching on/off of shunt capacitor banks in substations, vacuum circuit breakers (VCBs) are required to switch off or to switch on the capacitive current. Therefore, the VCBs have to be operated under a harsh condition to ensure the reliability of the equipment. This study presents a complete comparison study of ordinary and phase-controlled VCBs on switching 10 kV shunt capacitor banks. An analytical analysis for switching 10 kV shunt capacitor banks is presented on the basis of ...

  16. Budd-Chiari Syndrome: Long term success via hepatic decompression using transjugular intrahepatic porto-systemic shunt

    Schmidt Jan

    2010-03-01

    Full Text Available Abstract Background Budd-Chiari syndrome (BCS generally implies thrombosis of the hepatic veins and/or the intrahepatic or suprahepatic inferior vena cava. Treatment depends on the underlying cause, the anatomic location, the extent of the thrombotic process and the functional capacity of the liver. It can be divided into medical treatment including anticoagulation and thrombolysis, radiological procedures such as angioplasty and transjugular intrahepatic porto-systemic shunt (TIPS and surgical interventions including orthotopic liver transplantation (OLT. Controlled trials or reports on larger cohorts are limited due to rare disease frequency. The aim of this study was to report our single centre long term results of patients with BCS receiving one of three treatment options i.e. medication only, TIPS or OLT on an individually based decision of our local expert group. Methods 20 patients with acute, subacute or chronic BCS were treated between 1988 and 2008. Clinical records were analysed with respect to underlying disease, therapeutic interventions, complications and overall outcome. Results 16 women and 4 men with a mean age of 34 ± 12 years (range: 14-60 years at time of diagnosis were included. Myeloproliferative disorders or a plasmatic coagulopathy were identified as underlying disease in 13 patients, in the other patients the cause of BCS remained unclear. 12 patients presented with an acute BCS, 8 with a subacute or chronic disease. 13 patients underwent TIPS, 4 patients OLT as initial therapy, 2 patients required only symptomatic therapy, and one patient died from liver failure before any specific treatment could be initiated. Eleven of 13 TIPS patients required 2.5 ± 2.4 revisions (range: 0-8. One patient died from his underlying hematologic disease. The residual 12 patients still have stable liver function not requiring OLT. All 4 patients who underwent OLT as initial treatment, required re-OLT due to thrombembolic complications of

  17. Therapeutic application of 99Tc-MDP in advanced nodose rheumatoid patients with multiple arthrosis erosion and malfunctioning

    Objective: To evaluate clinical effect of 99Tc-MDP in treating arthrosis erosion in advanced nodose rheumatism. Methods: Therapy was performed undisrupted for 1 to 2 years in each patient at a high dose of 1.0-1.5 g/month. Results: After more than 1 year's 99Tc-MDP therapy, 10 patients with multiple arthrosis erosion and serious malfunctioning had function recovery and arthral reformation of different extent. Patients with obvious therapeutic effects were able to walk, travel and completely or partially took care of themselves. Cortisone was prohibited or permitted at a lower dose of 1.25 mg/day in 3 patients who were dependant on prednisone. As results from 99Tc-MDP therapy, X-ray photography revealed broadened arthral gap, reformation of previously eroded arthrosis and even improvement in osteoporosis. Conclusion: Reversible changes resulted from 99Tc-MDP therapy showed breakthrough in treatment of advanced nodose rheumatism and serious ostearthritis, whose pathological changes were previously considered irreversible

  18. An efficient method for monitoring the shunts in silicon solar cells during fabrication processes with infrared imaging

    Zhang Lucheng; Xu Xinxiang; Yang Zhuojian; Sun Xiaopu; Xu Hongyun; Liu Haobin; Shen Hui

    2009-01-01

    , and energy dispersive X-ray spectroscopy. Approaches for diminishing shunts are presented. The methods are beneficial for the optimization of the cell fabrication processes and the improvement of the cell performances.

  19. Ligation of Left Renal Vein for Spontaneous Splenorenal Shunt to Prevent Portal Hypoperfusion after Orthotopic Liver Transplantation

    Lampros Kousoulas

    2013-01-01

    Full Text Available We report a case of recovered portal flow by ligation of the left renal vein on the first postoperative day after orthotopic liver transplantation of a 54-year-old female with alcoholic liver cirrhosis, chronic kidney failure, and spontaneous splenorenal shunt. After reperfusion, Doppler ultrasonography showed almost total diversion of the portal flow into the existing splenorenal shunt, but because of severe coagulopathy and diffuse bleeding, ligation of the shunt was not attempted. A programmed relaparotomy was performed on the first postoperative day, and the left renal vein was ligated just to the left of the inferior vena cava. Portal flows subsequently increased to 37 cm/sec, and the patient presented a good and stable liver function. We conclude that patients with known preoperative splenorenal shunts should be closely monitored, and if the portal flow becomes insufficient, ligation of the left renal vein should be attempted in order to optimize the portal perfusion of the liver.

  20. Creation of an iliac arteriovenous shunt lowers blood pressure in chronic obstructive pulmonary disease patients with hypertension.

    Faul, John

    2014-01-28

    Vasodilators are used with caution in patients with chronic obstructive pulmonary disease (COPD). We have developed a device for percutaneous arteriovenous shunt creation in the iliac region to increase cardiac output and oxygen delivery for patients with COPD. Although this device does not cause significant blood pressure changes in normotensive patients with COPD, we hypothesized that arteriovenous shunt creation might cause vasodilator effects in hypertensive patients because of a reduction in vascular resistance.

  1. Unsatisfactory outcomes of prolonged ischemic priapism without early surgical shunts: our clinical experience and a review of the literature.

    Zheng, Da-Chao; Yao, Hai-Jun; Zhang, Ke; Xu, Ming-Xi; Chen, Qi; Chen, Yan-Bo; Cai, Zhi-Kang; Lu, Mu-Jun; Wang, Zhong

    2013-01-01

    Ischemic priapism is a rare occurrence which can cause severe erectile dysfunction (ED) without timely treatment. This retrospective study reports our experience in treating prolonged ischemic priapism and proposes our further considerations. In this paper, a total of nine patients with prolonged ischemic priapism underwent one to three types of surgical shunts, including nine Winter shunts, two Al-Ghorab shunts and one Grayhack shunt. During the follow-up visit (after a mean of 21.11 months), all patients' postoperative characters were recorded, except one patient lost for death. Six postoperative patients accepted a 25-mg oral administration of sildenafil citrate. The erectile function of the patients was evaluated by their postoperative 5-item version of International Index of Erectile Function Questionnaire (IIEF-5), which were later compared with their premorbid scores. All patients had complete resolutions, and none relapsed. The resolution rate was 100%. Seven patients were resolved with Winter shunts, one with an Al-Ghorab shunt and one with a Grayhack shunt. The mean hospital stay was 8.22 days. There was only one urethral fistula, and the incidence of postoperative ED was 66.67%. Four patients with more than a 72-h duration of priapism had no response to the long-term phosphodiesterase type 5 (PDE-5) inhibitor treatment. These results suggest that surgical shunts are an efficient approach to make the penis flaccid after prolonged priapism. However, the severe ED caused by prolonged duration is irreversible, and long-term PDE-5 inhibitor treatments are ineffective. Thus, we recommend early penile prosthesis surgeries for these patients. PMID:22922321

  2. Recurrent shunt associated ventriculitis caused by methicillin-resistant Staphylococcus aureus: Case with fatal outcome despite linezolid therapy

    Sadia Khan

    2012-01-01

    Full Text Available Ventriculoperitoneal shunt-associated ventriculitis is a serious though under-reported nosocomial complication of neurocritical settings. The treatment of CNS Methicillin-resistant Staphylococcus aureus (MRSA infections is usually successful with vancomycin or linezolid. Here, we report a case of ventriculitis due to MRSA following a shunt infection, which did not show clinical response to linezolid therapy. With the increasing use of invasive procedures, nosocomial infections have increased exponentially. Exercising extreme care in such CNS procedures becomes very important.

  3. Bihemispheric Paradoxical Cerebral Embolism in a Patient with Pulmonary Thromboembolism and Presumptive Fistula Right-to-Left Shunt.

    Zanati Bazan, Silméia Garcia; Braga, Gabriel Pereira; Luvizutto, Gustavo José; Trindade, André Petean; Pontes-Neto, Octávio Marques; Bazan, Rodrigo

    2016-06-01

    We report a case of a bihemispheric paradoxical cerebral embolism in a patient with pulmonary thromboembolism and presumptive pulmonary arteriovenous fistula. The echocardiogram showed no intracardiac shunt, and the transcranial Doppler (TCD) revealed spontaneous microembolic signals in the middle cerebral arteries (MCAs), and late passage of a higher number of microembolic signals in the MCAs, compatible with right-to-left shunt (RLS). The TCD and the echocardiogram were useful for identifying the RLS when rapid neurological deterioration occurred. PMID:27105566

  4. New temporary internal introducer shunt for brain perfusion during total endovascular arch replacement with in situ fenestration technique.

    Sonesson, Björn; Resch, Tim; Dias, Nuno; Malina, Martin

    2012-10-01

    Complete endovascular arch replacement by in situ fenestration technique requires maintenance of cerebral perfusion during the fenestration procedure by an extracorporeal femoral-carotid bypass. The bypass has the disadvantages of being invasive, requiring a pump, and shunting blood extracorporeally. This report describes bench testing and an in vivo experimental animal setup with an endovascular, temporary introducer shunt. This technique represents an adjunctive step toward a complete endovascular repair for the aortic arch. PMID:22857810

  5. Device malfunction caused by "auto-oversensing" of transthoracic impedance measurement test pulses in a modern minute ventilation dual-chamber pacemaker.

    Hansen, Claudius; Vollmann, Dirk; Neuzner, Jörg

    2016-07-01

    Oversensing of physiologic and non-physiologic electrical signals is a relevant cause of malfunctions in subjects with CIED. Physicians taking care of CIED patients must be aware of the potential causes of oversensing and their pattern in EGMs. The present case describes an uncommon source and unique underlying root cause for oversensing in a modern dual-chamber MV rate-adaptive pacemaker. PMID:26745956

  6. Radiological findings in complications of CSF-draining shunts in infantile hydrocephalus

    A CSF-draining system functioning free form disturbances is the precondition for age-appropriate further development of the brain in the treatment of infantile hydrocephalus. Shunt dysfuncion may be caused by infection but also by mechanical or functional disturbances with the latter two being summarized under the generic term of 'shunt insufficiency'. Imaging techniques rank first in diagnosis. Plain film X-raying will discover a possible misalignment of the system, a disconnection or a rupture with or without embolization of a valve section. Patency of the system can be verified by valvography using contrast medium or isotopes. CT plays a significant part in the diagnosis of 'hyperdrained' hydrocephalus. In rare cases, pulmonary hyperpressure with cor pulmonale due to chronic micro-embolization of the pulmonary vessels will be a late sequela, even if the position of the distal catheter part is correct. (orig.)

  7. Congenital Extrahepatic Portosystemic Shunts: Spectrum of Findings on Ultrasound, Computed Tomography, and Magnetic Resonance Imaging

    Congenital extrahepatic portosystemic shunt (CEPS) is a rare disorder characterised by partial or complete diversion of portomesenteric blood into systemic veins via congenital shunts. Type I is characterised by complete lack of intrahepatic portal venous blood flow due to an end to side fistula between main portal vein and the inferior vena cava. Type II on the other hand is characterised by partial preservation of portal blood supply to liver and side to side fistula between main portal vein or its branches and mesenteric, splenic, gastric, and systemic veins. The presentation of these patients is variable. Focal liver lesions, most commonly nodular regenerative hyperplasia, are an important clue to the underlying condition. This pictorial essay covers imaging characteristics in abdominopelvic region

  8. Simulation Research of Transient Over-voltage on High-voltage Shunt Capacitor Banks

    HU Quan-wei; ZHOU Xing-xing; SI Wen-rong; ZHANG Yang; LI Jur-hao; LI Yan-ming

    2011-01-01

    With the development of power systems,a large number of shunt capacitors are used to improve power quality in the distribution network.The shunt capacitor banks are operated much frequently,as a result,the capacitor banks will bear large numbers of over-voltage inevitably.If the over-voltage exceeds certain amplitude,the capacitor will be damaged.This paper aims at the capacitor banks in the 35 kV side of Shanghai Xu-xing 500 kV substation,and applies ATP-EMTP to simulate the over-voltages generated by operating the switches under different angles of the source.Finally,according to the results of simulation and theoretical analysis,a best choice (i.e.angles of the source) to switch on capacitor banks is proposed.In this case the over-voltage on the capacitor will be limited to lowest.

  9. Development of the Unified Series-Shunt Compensator for Power Quality Mitigation

    M. A. Hannan

    2009-01-01

    Full Text Available This study describes the derivation of an analytical model and simulation for the unified series-shunt compensator (USSC for investigating power quality in power distribution system. The USSC simulation comprises of two 12-pulse inverters which were connected in series and in shunt with the system. A generalized sinusoidal pulse width modulation (SPWM switching technique was developed in the proposed controller for fast control action of the USSC. Simulations were carried out using the PSCAD/EMTDC electromagnetic transient programs to examine the performance of the USSC model. Simulation results from the proposed model demonstrated the performance of the USSC and its effectiveness for voltage sag compensation, flicker reduction, voltage unbalance mitigation, power flow control and harmonics elimination.

  10. A New Soft-Switched Three-Phase Four-Wire Shunt Active Power Filter

    Mohammad Reza Moradian

    2010-07-01

    Full Text Available This paper presents a new soft switched topology for losses reduction in a three-phase four-wire shunt active power filter (SAPF. The soft-switching technique not only offers a reduction in switching loss and thermal requirement, but also allows the possibility of high frequency and snubberless operation. Improved circuit performance and efficiency as well as reduction of EMI emission can be achieved. The resonant dc link inverter with low voltage stress is used for power converter of a three-phase four-wire shunt active power filter. It is assumed that the active power filter is connected to a load that can be unbalanced and may also draw harmonic currents. The p-q theory is used for controlling the SAPF. The proposed topology and operation principle of the control method is discussed in detail, finally the feasibility of such a scheme is demonstrated through simulation studies.

  11. Design and Implementation of Takagi-Sugeno Fuzzy Logic Controller for Shunt Compensator

    Singh, Alka; Badoni, Manoj

    2015-08-01

    This paper describes the application of Takagi-Sugeno (TS) type fuzzy logic controller to a three-phase shunt compensator in power distribution system. The shunt compensator is used for power quality improvement and has the ability to provide reactive power compensation, reduce the level of harmonics in supply currents, power factor correction and load balancing. Additionally, it can also be used to regulate voltage at the point of common coupling (PCC). The paper discusses the design of TS fuzzy logic controller and its implementation based on only four rules. The smaller number of rules makes it suitable for experimental verification as compared to Mamdani fuzzy controller. A small laboratory prototype of the system is developed and the control algorithm is verified experimentally. The TS fuzzy controller is compared with the proportional integral based industrial controller and their performance is compared under a wide variation of dynamic load changes.

  12. Congenital Extrahepatic Portosystemic Shunts: Spectrum of Findings on Ultrasound, Computed Tomography, and Magnetic Resonance Imaging

    Gupta, Pankaj; Sinha, Anindita; Sodhi, Kushaljit Singh; Lal, Anupam; Debi, Uma; Thapa, Babu R.; Khandelwal, Niranjan

    2015-01-01

    Congenital extrahepatic portosystemic shunt (CEPS) is a rare disorder characterised by partial or complete diversion of portomesenteric blood into systemic veins via congenital shunts. Type I is characterised by complete lack of intrahepatic portal venous blood flow due to an end to side fistula between main portal vein and the inferior vena cava. Type II on the other hand is characterised by partial preservation of portal blood supply to liver and side to side fistula between main portal vein or its branches and mesenteric, splenic, gastric, and systemic veins. The presentation of these patients is variable. Focal liver lesions, most commonly nodular regenerative hyperplasia, are an important clue to the underlying condition. This pictorial essay covers imaging characteristics in abdominopelvic region. PMID:26858845

  13. Congenital Extrahepatic Portosystemic Shunts: Spectrum of Findings on Ultrasound, Computed Tomography, and Magnetic Resonance Imaging

    Pankaj Gupta

    2015-01-01

    Full Text Available Congenital extrahepatic portosystemic shunt (CEPS is a rare disorder characterised by partial or complete diversion of portomesenteric blood into systemic veins via congenital shunts. Type I is characterised by complete lack of intrahepatic portal venous blood flow due to an end to side fistula between main portal vein and the inferior vena cava. Type II on the other hand is characterised by partial preservation of portal blood supply to liver and side to side fistula between main portal vein or its branches and mesenteric, splenic, gastric, and systemic veins. The presentation of these patients is variable. Focal liver lesions, most commonly nodular regenerative hyperplasia, are an important clue to the underlying condition. This pictorial essay covers imaging characteristics in abdominopelvic region.

  14. On-line process analysis innovation: DiComp (tm) shunting dielectric sensor technology

    Davis, Craig R.; Waldman, Frank A.

    1993-01-01

    The DiComp Shunting Dielectric Sensor (SDS) is a new patent-pending technology developed under the Small Business Innovation Research Program (SBIR) for NASA's Kennedy Space Center. The incorporation of a shunt electrode into a conventional fringing field dielectric sensor makes the SDS uniquely sensitive to changes in material dielectric properties in the KHz to MHz range which were previously detectable only at GHz measurement frequencies. The initial NASA application of the SDS for Nutrient Delivery Control has demonstrated SDS capabilities for thickness and concentration measurement of Hoagland nutrient solutions. The commercial introduction of DiComp SDS technology for concentration and percent solids measurements in dispersions, emulsions and solutions represents a new technology for process measurements for liquids in a variety of industries.

  15. Effect of Circuit Breaker Shunt Resistance on Chaotic Ferroresonance in Voltage Transformer

    RADMANESH, H.

    2010-08-01

    Full Text Available Ferroresonance or nonlinear resonance is a complex electrical phenomenon, which may cause over voltages and over currents in the electrical power system which endangers the system reliability and continuous safe operating. This paper studies the effect of circuit breaker shunt resistance on the control of chaotic ferroresonance in a voltage transformer. It is expected that this resistance generally can cause ferroresonance dropout. For confirmation this aspect Simulation has been done on a one phase voltage transformer rated 100VA, 275kV. The magnetization characteristic of the transformer is modeled by a single-value two-term polynomial with q=7. The simulation results reveal that considering the shunt resistance on the circuit breaker, exhibits a great mitigating effect on ferroresonance over voltages. Significant effect on the onset of chaos, the range of parameter values that may lead to chaos along with ferroresonance voltages has been obtained and presented.

  16. A novel low-profile ventriculoamniotic shunt for foetal aqueductal stenosis.

    Chen, Yanfei; Emery, Stephen P; Maxey, Antonina P; Gu, Xinzhu; Wagner, William R; Chun, Youngjae

    2016-01-01

    This study proposed a novel ventriculoamniotic shunt device for foetal aqueductal stenosis treatment fabricated with 3Fr or 4Fr size catheters that have a longitudinal bending stiffness with kink resistance, sufficient luminal area for cerebrospinal fluid drainage and capacity for valve integration. Computational flow dynamics studies were carried out to optimise the device design, including size of the lumen and length of the device. An in vitro pressure and flow rate measurement test circuit was constructed to assess the high pressure relieving functionality of draining cerebrospinal fluid from foetal brain. Additionally, a resistance force measurement test platform was built to quantitatively evaluate the anchor performance of various geometric designs. The valve functionality was qualitatively evaluated through the visualisation of the flow patterns in the amniotic sac with injected red coloured fluid under stereomicroscopy. These in vitro results demonstrate the feasibility of the ventriculoamniotic shunt device designed for placement in the foetal brain. PMID:27004923

  17. Integration of Thermal Energy Harvesting in Semi-Active Piezoelectric Shunt-Damping Systems

    Lubieniecki, Michał; Uhl, Tadeusz

    2015-01-01

    The opportunities to energize a broad range of devices by use of energy available almost anywhere and in many forms are almost unlimited. A major advantage of energy harvesting is the manufacture of small autonomous electronic devices with no need for power supply and maintenance. Shunt damping circuits, although unfavorably affected by the size and mass of bulky coil inductors, started to base on synthetic inductors losing their passivity. In this paper we report a study of the feasibility of powering shunt damping circuits by use of thermal energy otherwise irrevocably lost from a bearing. The heat generated in the bearing is converted thermoelectrically into electric energy which is then used to power synthetic inductance circuitry. We show that the power demand of such circuit can be satisfied by use of a thermoelectric generator paired with a moderately loaded bearing.

  18. Thoraco-amniotic shunting for fetal pleural effusion--a case series.

    Walsh, J

    2011-11-15

    Fetal pleural effusion is a rare occurrence, with an incidence of 1 per 10-15,000 pregnancies. The prognosis is related to the underlying cause and is often poor. There is increasing evidence that in utero therapy with thoraco-amniotic shunting improves prognosis by allowing lung expansion thereby preventing hydrops and pulmonary hypoplasia. This is a review of all cases of fetal pleural effusion managed over an eight year period the National Maternity Hospital Dublin. Over the nine year period there were 21 cases of fetal pleural effusion giving an overall incidence of 1 per 9281 deliveries. Of these, 15 underwent thoraco-amniotic shunting. There were associated anomalies diagnosed in 5 (33%) of cases. The overall survival in our cohort was 53%. The presence of hydrops was a poor prognostic factor, with survival in cases with hydrops of 33% (3\\/9) compared to 83% (5\\/6) in those cases without associated hydrops.

  19. Design of tunable acoustic metamaterials through periodic arrays of resonant shunted piezos

    Periodic shunted piezoelectric patches are employed for the design of a tunable, one-dimensional metamaterial. The configuration considered encompasses a beam undergoing longitudinal and transverse motion, and a periodic array of piezoelectric patches with electrodes connected to a resonant electric circuit. The resulting acousto-electrical system is characterized by an internal resonant behavior that occurs at the tuning frequency of the shunting circuits, and is analogous in its operation to other internally resonating systems previously proposed, with the addition of its simple tunability. The performance of the beam is characterized through the application of the transfer matrix approach, which evaluates the occurrence of bandgaps at the tuning frequencies and estimates wave attenuation within such bands. Moreover, a homogenization study is conducted to illustrate the internal resonant characteristics of the system within an analytical framework. Experiments performed on the considered beam structure validate the theoretical predictions and illustrate its internal resonant characteristics and the formation of the related bandgaps. (paper)

  20. Development of shunt regulated high stability septum power supplies for Booster upgradation

    The work describes design and development aspects of high stability septum power supplies.These power supplies will energize septum magnets by damped half sine wave current pulse. The damped half sine current pulse is generated by discharging a bank of energy storage capacitors into magnet load. Thyristor is used as a controlled switch. The process of injection and extraction of bunches from Booster takes place at the flat top portion of the current pulse and therefore peak current stability and pulse to pulse current amplitude stability are of prime importance. The stability of current pulse is mainly governed by ability of control scheme to maintain capacitor voltage at desired level.The proposed scheme uses a series resonant converter followed by shunt regulator in linear mode to achieve above mentioned objectives. The output capacitor voltage stability of ± 20 ppm is achieved by the use of shunt regulator. The design of developed power supplies and experimental results will be discussed. (author)

  1. Application of VSC-HVDC with Shunt Connected SMES for Compensation of Power Fluctuation

    Linn, Zarchi; Kakigano, Hiroaki; Miura, Yushi; Ise, Toshifumi

    This paper describes the application of VSC-HVDC (High Voltage DC Transmission using Voltage Source Converter) with shunt connected SMES (Superconducting Magnetic Energy Storage) for compensation of power fluctuation caused by fluctuating power source such as photovoltaics and wind turbines. The objectives of this proposed system is to smooth out fluctuating power in one terminal side of HVDC in order to avoid causing power system instability and frequency deviation by absorbing or providing power according to the system requirement while another terminal side power is fluctuated. The shunt connected SMES charges and discharges the energy to and from the dc side and it compensates required power of fluctuation to obtain constant power flow in one terminal side of VSC-HVDC system. This system configuration has ability for power system stabilization in the case of power fluctuation from natural energy source. PSCAD/EMTDC simulation is used to evaluate the performance of applied system configuration and control method.

  2. The power output and efficiency of a negative capacitance shunt for vibration control of a flexural system

    A negative capacitance shunt is a basic, analog, active circuit electrically connected to a piezoelectric transducer to control the vibrations of flexural bodies. The shunt circuit consists of a resistor and a synthetic negative capacitor to introduce a real and imaginary impedance on a vibrating mechanical system. The electrical impedance of the negative capacitance shunt modifies the effective modulus of the piezoelectric transducer to reduce the stiffness and increase the damping, which causes a decrease in amplitude of the vibrating structure to which the elements are bonded. To gain an insight into the electromechanical coupling and power output, the shunt and the electrical properties of the piezoelectric transducer are modeled using circuit modeling software. The power output of the model is validated with experimental measurements of a shunt connected to a piezoelectric transducer pair bonded to a vibrating aluminum cantilever beam. The model is used to select the passive components of the negative capacitance shunt to increase the efficiency and quantify the voltage output limit of the op-amp. (paper)

  3. Field Experiments on 10 kV Switching Shunt Capacitor Banks Using Ordinary and Phase-Controlled Vacuum Circuit Breakers

    Wenxia Sima

    2016-01-01

    Full Text Available During the switching on/off of shunt capacitor banks in substations, vacuum circuit breakers (VCBs are required to switch off or to switch on the capacitive current. Therefore, the VCBs have to be operated under a harsh condition to ensure the reliability of the equipment. This study presents a complete comparison study of ordinary and phase-controlled VCBs on switching 10 kV shunt capacitor banks. An analytical analysis for switching 10 kV shunt capacitor banks is presented on the basis of a reduced circuit with an ungrounded neutral. A phase selection strategy for VCBs to switch 10 kV shunt capacitor banks is proposed. Switching on current waveforms and switching off overvoltage waveforms with, and without, phase selection were measured and discussed by field experiments in a 110 kV substation in Chongqing, China. Results show that the operation of phase-controlled VCBs for 10 kV switching shunt capacitor banks is stable, and phase-controlled VCBs can be used to implement the 10 kV switching on/off shunt capacitor banks to limit the transient overvoltage and overcurrent. The values of overvoltage and inrush current using phase-controlled VCBs are all below those with ordinary VCBs.

  4. Relation of shunting current at cracked part to critical current and n-value in multifilamentary Bi2223 composite tape

    Relation of transport current and n-value to collective crack-induced current shunting in BSCCO (Bi2223) multi-filamentary composite tape pulled in tension was studied experimentally and analytically. For analysis, the partial crack-current shunting model of Fang et al. was used by placing the collective crack as the partial one. It was shown that (a) collective crack-induced shunting current increases with increasing current (and voltage) and with increasing collective crack size, (b) the transport current normalized with respect to the transport current in non-cracked state is described with the modified ratio of non-cracked area to overall cross-sectional area of superconducting filaments at low voltage where shunting current is low, while it deviates upward from the modified ratio at high voltage where the shunting current is enhanced, and (c) the enhanced shunting current acts to reduce n-value at high voltage. These features were similar to those of cracked coated conductor. (author)

  5. Radionuclide imaging for the assessment of the latency of peritoneovenous (Le Veen) shunt in the treatment of refractory ascities

    A peritoneovenous (Le Veen) shunt was surgically implanted in eight patients with hepatic cirrhosis and persistent ascites in order to obtain a peritoneouvenous drainage. All patients were resistant to the medical therapy. Because of the high incidence of immediate postoperative complications of newly implanted shunts, including valvular thrombosis, the Authors used a non invasive imaging technique to control the shunt function by injecting 99mTc microcolloidal albumin in the peritoneal cavity (peritoneal scintigraphy) in 7 patients, whereas the eighth patient received an equivalent dose of 99mTc-Human-Albumin Microspheres. In all cases the scan showed a well functioning of peritoneovenous (Le Veen) shunt. The Authors emphasize the role of this type of scintigraphy for the control of the patency of Le Veen shunt. For the case of Albumin Microspheres, the transvalvular flow can be demonstrated also by means of the pulmonary uptake of 99mTc-MAA, which is an indirect test of normal functioning of peritoneovenous shunt

  6. Programmable shunt valves: in vitro assessment of safety of the magnetic field generated by a portable game machine.

    Nakashima, Koji; Nakajo, Takato; Kawamo, Michiari; Kato, Akihito; Ishigaki, Seiichiro; Murakami, Hidetomo; Imaizumi, Yohichi; Izumiyama, Hitoshi

    2011-01-01

    Cerebrospinal fluid (CSF) shunts are frequently used to treat hydrocephalus. The use of a programmable shunt valve allows physicians to easily change the opening pressure. Since patients with adjustable CSF shunt valves may use portable game machines, the permanent magnets in these machines may alter the shunt valve programmed settings or permanently damage the device. This study investigated the risk of unintentional valve adjustment associated with the use of game machines in patients with programmable CSF shunt valves. Four adjustable valves from 4 different manufacturers, Sophysa Polaris model SPV (Polaris valve), Miethke proGAV (proGAV), Codman Hakim programmable valve (CHPV), and Strata II small valve (Strata valve), were evaluated. Magnetic field interactions were determined using the portable game machine, Nintendo DS Lite (DS). The maximum distance between the valve and the DS that affected the valve pressure setting was measured by x-ray cinematography. The Polaris valve and proGAV were immune to unintentional reprogramming by the DS. However, the settings of the CHPV and Strata valves were randomly altered by the DS. Patients with an implanted shunt valve should be made aware of the risks posed by the magnetic fields associated with portable game machines and commonly used home electronics. PMID:21946726

  7. About the operation efficiency increase of high-power shunt reactors

    Жорняк, Людмила Борисовна; Осинская, Валентина Ивановна; Пальцун, Андрей Сергеевич

    2014-01-01

    Ways to increase the voltage quality in energy-intensive customers’ networks are investigated. Presence of the reactive power in transmission networks decreases essentially quality of electric energy input that results in power losses, voltage subsidences and drops in power transmission lines, enforced increase of power transformers’ power and cable sections in such networks. An engineering solution to decrease additional losses of a shunt reactor is proposed, analysis of different types of w...

  8. Pengaruh Pengaturan Tahanan Shunt Dan Seri Terhadap Putaran Dan Efisiensi Motor Arus Searah Kompon

    Sitorus, Andri

    2015-01-01

    Motor arus searah adalah suatu mesin yang berfungsi mengubah tenaga listrik arus searah menjadi tenaga gerak atau tenaga mekanik berupa putaran rotor. Putaran dan efisiensi merupakan besaran yang menentukan kinerja dari suatu motor arus searah. Dengan pengaturan tahanan shunt, putaran motor arus searah kompon panjang rata-rata lebih cepat 7,78% dibanding motor arus searah kompon pendek dengan tegangan terminal 50 V. Sedangkan dengan pengaturan tahanan seri, putaran motor aru...

  9. Correlations between scanning method and shunt index in the evaluation of the pulmonary systemic flux

    Full text: The radioisotopic method most used to the relative quantification of the pulmonary/systemic flux is the scanning or total body spots, which demands time and is subjected to errors in the quantification. Shunt index (SI) require only an acquisition of one image in the brain posterior incidence and one image in the lung posterior incidence, with posterior quantification.Our objective was to correlate the values obtained by the scanning method and shunt index. 240 pediatric patients bearing congenital cardiopathy with pulmonary hypo-flux (177) or pulmonary arterio-venous fistulas (63), were studied. The patients received Tc-99m human albumin macro-aggregates by venous injection (1.8 MBq/kg, maximum of 51 MBq up to 100.000 particles).Two types of acquisition were realized: the total body scanning (anterior and posterior) and spots in the posterior incidence of the brain and lungs. From the scanning on, the percentage concerned to the pulmonary flux (PI) was obtained and, from the spots on, the shunt index (SI) was obtained, using the formulas: PI=(Cp/Cl)x100 and SI(Cp/Cl)x100, where C=countings, p=lungs, t=total body, e=brain.The obtained values by the different techniques were plotted in a graphic, resulting in a correlation formula between the values PI = - 8,55 ln (SI) + 74,45. With this formula the shunt index is converted to % of macroaggregated albumin (MAA) in lungs, taking the SI more comprehensive in the clinic procedure. The SI determination, besides being a reliable method, practical and of easy execution, allows a time economy and provide more convenience for the patient

  10. Outcome of shunt operation on urinary incontinence in normal pressure hydrocephalus predicted by lumbar puncture.

    Ahlberg, J.; Norlén, L; Blomstrand, C; Wikkelsö, C

    1988-01-01

    Bladder function in four patients with normal pressure hydrocephalus, one with dementia of Alzheimer type and five patients with multi-infarct dementia was studied by history and urodynamic tests (cystometry and Bor's ice water test). The bladder hyperactivity could be temporarily improved by a lumbar puncture and removal of 50 ml CSF and later abolished by a shunt operation in patients with normal pressure hydrocephalus while no changes occurred in the other patients. Urodynamic testing in c...

  11. Malignant Ascites after Subduroperitoneal Shunt in a Patient with Leptomeningeal Metastasis

    Lee, Min Ho; Lee, Jung-Il

    2011-01-01

    Leptomeningeal metastasis is a devastating complication of advanced stage cancer. It is frequently accompanied by hydrocephalus and intracranial hypertension that must be treated by ventriculoperitoneal shunts. However, there are actual risks of peritoneal seeding or accumulation of malignant ascites after the cerebrospinal fluid diversion procedure, though it has not been reported. Here, we present the case of a patient with non-small cell lung cancer with leptomeningeal metastasis in whom m...

  12. Embolization of Portosystemic Shunts for Treatment of Medically Refractory Hepatic Encephalopathy

    Lynn, Amanda M.; Singh, Siddharth; Congly, Stephen E; Khemani, Disha; Johnson, David H.; Wiesner, Russell H.; Kamath, Patrick S.; Andrews, James C.; Leise, Michael D

    2016-01-01

    Treatment options for refractory hepatic encephalopathy (HE) are limited. Patients who fail medical management may harbor large portosystemic shunts (PSSs) which are possible therapeutic targets. This study aims to describe patient selection, effectiveness, and safety of percutaneous PSS embolization in those with medically refractory HE. A retrospective evaluation of consecutive adult patients with medically refractory HE referred for PSS embolization at a tertiary center was performed (2003...

  13. Scintigraphic procedures for the proof of peritoneo-venous shunt patency. 16

    Peritoneous shunt patency can be evaluated scintigraphically after intraperitoneal injection of 99mTc-labelled macro-aggregated albumin. Rapid accumulation of the particles in the lungs is an indicator of patency. If no radioactivity occurs in the lungs, the system is obstructed. After a second injection into the valve body the scintigraphic localization of the obstruction is possible. (author). 10 refs.; 5 figs

  14. Irreversible Electroporation of a Hepatocellular Carcinoma Lesion Adjacent to a Transjugular Intrahepatic Portosystemic Shunt Stent Graft

    We report in a 65-year-old man hepatocellular carcinoma adjacent to a transjugular intrahepatic portosystemic shunt stent-graft which was successfully treated with irreversible electroporation (IRE). IRE is a new non-thermal tissue ablation technique which uses electrical pulses to induce cell necrosis by irreversible membrane poration. IRE proved to be more advantageous in the ablation of perivascular tumor with little injury to the surrounding structures

  15. Irreversible Electroporation of a Hepatocellular Carcinoma Lesion Adjacent to a Transjugular Intrahepatic Portosystemic Shunt Stent Graft

    Niessen, Christoph; Jung, Ernst Michael; Wohlgemuth, Walter A. [Department of Radiology, University Medical Center Regensburg, Regensburg D-93053 (Germany); Trabold, Benedikt [Department of Anaesthesia, University Medical Center Regensburg, Regensburg D-93053 (Germany); Haimerl, Michael; Schreyer, Andreas; Stroszczynski, Christian; Wiggermann, Philipp [Department of Radiology, University Medical Center Regensburg, Regensburg D-93053 (Germany)

    2013-07-01

    We report in a 65-year-old man hepatocellular carcinoma adjacent to a transjugular intrahepatic portosystemic shunt stent-graft which was successfully treated with irreversible electroporation (IRE). IRE is a new non-thermal tissue ablation technique which uses electrical pulses to induce cell necrosis by irreversible membrane poration. IRE proved to be more advantageous in the ablation of perivascular tumor with little injury to the surrounding structures.

  16. LTC And Shunt Capacitor Switching In Smart Grid: Sensitivity To Plug-In Electric Vehicle Forecasts

    Sara Deilami

    2015-01-01

    Optimal scheduling of transformer load tap changer (LTC) and switched shunt capacitors (SSCs) in smart grid (SG) with plug-in electric vehicles (PEVs) and nonlinear loads can be performed to reduce system losses, node voltage fluctuations and total harmonic distortion (THD). This paper investigates the effects of vehicles’ plug-in time forecast errors on performance of LTC and SSCs switching. First, a genetic algorithm (GA) is used to determine the optimal switching schedules with...

  17. Engineering of Synthetic Reverse Glyoxylate Shunt Module for enhanced carbon incorporation in cyanobacteria

    Li, Xiaoqian

    2016-01-01

    Synthetic Biology and Metabolic engineering research aim to elucidate the underlying principle of biological systems and enable a predicable cellular behavior through artificial design. In this work, the discipline of synthetic biology was applied to photosynthetic organism to improve carbon intake efficiency. After survey and analysis of existing carbon fixation metabolic pathways, the design of a synthetic Reverse Glyoxylate Shunt (rGS) core module was invented. This core module could pote...

  18. Predictors and outcomes of shunt-dependent hydrocephalus in patients with aneurysmal sub-arachnoid hemorrhage

    Wang Yi-Min

    2012-07-01

    Full Text Available Abstract Background Hydrocephalus following spontaneous aneurysmal sub-arachnoid hemorrhage (SAH is often associated with unfavorable outcome. This study aimed to determine the potential risk factors and outcomes of shunt-dependent hydrocephalus in aneurysmal SAH patients but without hydrocephalus upon arrival at the hospital. Methods One hundred and sixty-eight aneurysmal SAH patients were evaluated. Using functional scores, those without hydrocephalus upon arrival at the hospital were compared to those already with hydrocephalus on admission, those who developed it during hospitalization, and those who did not develop it throughout their hospital stay. The Glasgow Coma Score, modified Fisher SAH grade, and World Federation of Neurosurgical Societies grade were determined at the emergency room. Therapeutic outcomes immediately after discharge and 18 months after were assessed using the Glasgow Outcome Score. Results Hydrocephalus accounted for 61.9% (104/168 of all episodes, including 82 with initial hydrocephalus on admission and 22 with subsequent hydrocephalus. Both the presence of intra-ventricular hemorrhage on admission and post-operative intra-cerebral hemorrhage were independently associated with shunt-dependent hydrocephalus in patients without hydrocephalus on admission. After a minimum 1.5 years of follow-up, the mean Glasgow outcome score was 3.33 ± 1.40 for patients with shunt-dependent hydrocephalus and 4.21 ± 1.19 for those without. Conclusions The presence of intra-ventricular hemorrhage, lower mean Glasgow Coma Scale score, and higher mean scores of the modified Fisher SAH and World Federation of Neurosurgical grading on admission imply risk of shunt-dependent hydrocephalus in patients without initial hydrocephalus. These patients have worse short- and long-term outcomes and longer hospitalization.

  19. Shunt-capacitor-assisted synchronization of oscillations in intrinsic Josephson junctions stack

    Martin, I.; Halász, Gábor B.; Bulaevskii, L. N.; Koshelev, A. E.

    2010-01-01

    We show that shunt capacitor stabilizes synchronized oscillations in intrinsic Josephson junction stacks biased by DC current. This synchronization mechanism has an effect similar to the previously discussed radiative coupling between junctions, however, it is not defined by the geometry of the stack. It is particularly important in crystals with smaller number of junctions, where radiation coupling is week, and is comparable with the effect of strong super-radiation in crystal with many junc...

  20. PI, FUZZY and ANFIS Control of 3-Phase Shunt Active Power Filter

    Brahmaiah.routhu

    2013-06-01

    Full Text Available this paper describes control of 3-phase shunt active filter by using PI, fuzzy and ANFIS controls to improve the power quality and reactive power compensation and harmonic current compensation due to nonlinear loads. The controller is capable of controlling the DC capacitor voltage capable of reference source current. Hysteresis control is used to control the current in PWM inverter. The simulation results reveals that comparative study of all this results shows the advantage anddisadvantages of 3 control strategies.