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Sample records for tc-99m-disida hepatobiliary kinetics

  1. Gastric Reflux on Routine Tc-99m DISIDA hepatobiliary Scintigraphy

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Kang Wook; Lee, Heon Young [Chungnam National University College of Medicine, Daejeon (Korea, Republic of)

    1995-06-15

    Reflux of bile and digestive enzymes from the small bowel and duodenum into stomach has been observed in patients with various gastroduodenal diseases. Tc-99m iminodiacetic acid derivatives hepatobiliary scan has been used as a noninvasive method to detect duodenogastric reflux. Sometimes, gastric reflux can be observed incidentally on routine Tc-99m DISA hepatobiliary scintigraphy. To evaluate the clinical meaning of gastric reflux on routine Tc-99m DISIDA hepatobiliary scan, we analyzed 36 patients showed gastric reflux incidentally on the routine Tc-99m-DISIDA hepatobiliary scintigraphy from December 1991 to June 1995 in Chungnam National University Hospital. The results were as follows: 1) The gastric reflux was observed in 2.3% of 1,553 cases of routine Tc-99m DISIDA Hepatobiliary scintigraphy for 43 months. 2) Nineteen percent of patients with gastric reflux had the past medical history of operations on stomach or biliary system. And that history was more prevalent in patients with reflux than those without reflux, significantly (p<0.01). 3) On fiberoptic gastroduodenpscopic examination, 87% of the patients with gastric reflux had the gastroduodenal diseases such as gastritis, gastric ulcer, duodenal ulcer, gastric cancer, duodenal cancer and ampullary diverticulosis. We thought that the gastric reflux can be observed considerably in patients without any operation history on stomach or duodenum, although the operation history is more prevalent in patients with gastric reflux than those without reflux, significantly and most of patients with gastric reflux on routine Tc-99m DISIDA scan has various gastroduodenal diseases.

  2. Gastric Reflux on Routine Tc-99m DISIDA hepatobiliary Scintigraphy

    International Nuclear Information System (INIS)

    Lee, Kang Wook; Lee, Heon Young

    1995-01-01

    Reflux of bile and digestive enzymes from the small bowel and duodenum into stomach has been observed in patients with various gastroduodenal diseases. Tc-99m iminodiacetic acid derivatives hepatobiliary scan has been used as a noninvasive method to detect duodenogastric reflux. Sometimes, gastric reflux can be observed incidentally on routine Tc-99m DISA hepatobiliary scintigraphy. To evaluate the clinical meaning of gastric reflux on routine Tc-99m DISIDA hepatobiliary scan, we analyzed 36 patients showed gastric reflux incidentally on the routine Tc-99m-DISIDA hepatobiliary scintigraphy from December 1991 to June 1995 in Chungnam National University Hospital. The results were as follows: 1) The gastric reflux was observed in 2.3% of 1,553 cases of routine Tc-99m DISIDA Hepatobiliary scintigraphy for 43 months. 2) Nineteen percent of patients with gastric reflux had the past medical history of operations on stomach or biliary system. And that history was more prevalent in patients with reflux than those without reflux, significantly (p<0.01). 3) On fiberoptic gastroduodenpscopic examination, 87% of the patients with gastric reflux had the gastroduodenal diseases such as gastritis, gastric ulcer, duodenal ulcer, gastric cancer, duodenal cancer and ampullary diverticulosis. We thought that the gastric reflux can be observed considerably in patients without any operation history on stomach or duodenum, although the operation history is more prevalent in patients with gastric reflux than those without reflux, significantly and most of patients with gastric reflux on routine Tc-99m DISIDA scan has various gastroduodenal diseases.

  3. Evaluation of hepatobiliary imaging using Tc-99m-DISIDA in hepatobiliary disease

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    Kim, Yong Ga; Chung, Duck Soo; Kim, Ok Dong [Taegu Catholic Hospital, Daegu (Korea, Republic of)

    1985-06-15

    Hepatobiliary scintigraphy using Tc-labelled radiopharmaceuticals is employed primarily for the diagnosis of acute cholecystitis and for demonstration of biliary tract patency. We concluded a retrospective study of 55 patients with hepatobiliary disease from Jun. '84 to Sep. '84 at Taegu Catholic Hospital and tried to determine the etiology and find the possible differential points by analyzing the scintigraphic findings. The following results were obtained; 1. Tree-like photon defect on hepatic parenchyme was suggested characteristic of complete obstructive biliary disease, but could be seen in either benign or malignant etiology. 2. The grade of hepatocyte clearance was not useful in determining whether the cause of obstructive biliary disease was benign or malignant in this study. 3. Hepatocyte clearance was more severely impaired in hepatocellular disease than in obstructive biliary disease. 4. The photon defect in porta hepatis with complete biliary obstruction was suggested characteristic of common bile duct cancer. 5. The meniscus appearance at obstructed site of common bile duct was pathognomonic sign of choledocholithiasis. 6. When the gallbladder was not visualized, the differential diagnosis between acute and chronic cholecystitis was possible without delayed image by observing the transit time to bowel. The delayed transit to bowel was a favorable of chronic cholecystitis rather than of acute cholecystitis. 7. Acute pancreatitis could be easily differentiated from partial biliary obstruction by clinical and laboratory examination, but the finding of abrupt narrowing of pancreatic common bile duct with slight proximal dilatation on cholescintigraphy was also a key point in acute pancreatitis. 8. The segmental dilatation of intrahepatic duct was thought meaningful sign of clonorchiasis.

  4. Evaluation of the biliary gallbladder emptying in patients with calcificant chronic pancreatitis through a scintilographic study with DISIDA Tc-99m; Avaliacao do esvaziamento da vesicula biliar em portadores de pancreatite cronica calcificante, atraves do estudo cintilografico com Tc-99m DISIDA

    Energy Technology Data Exchange (ETDEWEB)

    Pedroso, Martha Regina Arcon

    1996-07-01

    The eventual relation between biliary lithiasis and chronic pancreatitis (CP) has been studied before but the research on the gallbladder involvement in chronic pancreatitis patients are rare, specially from a functional point of view. In order to study that, gallbladder emptying was evaluated in 11 patients with CP and the results were compared and analyzed statistically with the ones observed in 10 controls. This series exclude patients and controls who presented any kind of prior or current affection, or condition, that could interfere with the gastric or gallbladder emptying and the release of the entero pancreatic hormones. Gallbladder emptying was studied through the scintillographic method, using Tc-99m DISIDA, through the calculation of the ejection (EF) of the gallbladder (GB), at 30, 45 and 60 minutes. In the patients this evaluation was studied in two different periods of time with an interval of two to four weeks between them, without (CPWOP) and with (CPWP) the addition of pancreatic extract. The analyses of the results disclosed that the EF of GB at 60 minutes was significantly higher in the controls when compared tro chronic pancreatopaths. On the other hand, the EF of GB in these patients did not show any statistically significant differences after the administration of pancreatic extract. The results suggest that the delay in the gallbladder emptying does not depend exclusively on the eventual alteration in the intestinal phase of the gallbladder stimulation, but it probably also results from the association with other factors involved, as a mechanic factor, which depends on the compression of the main biliary tract through the chronic pathological process located in the cephalic portion of the pancreas. (author)

  5. Hepatobiliary

    Science.gov (United States)

    ... exam. You should not have tests that use barium for 48 hours before hepatobiliary imaging. top of ... passing x-rays through the patient's body. In contrast, nuclear medicine procedures use a radioactive material, called ...

  6. The role of hepatobiliary scintigraphy and oral cholecystography in predicting the performance of laparoscopic cholecystectomy

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    Won, Kyoung Sook [Kangnung Hospital, Kangnung (Korea, Republic of); Ryu, Jin Sook; Moon, Dae Hyuk [College of Medicine, Ulsan Univ., Seoul (Korea, Republic of)] [and others

    1997-03-01

    Laparoscopic cholecystectomy can be performed safely in most patients with symptomatic cholelithiasis. Preoperative evaluation should assess the potential problems that affect the performance of laparoscopic cholecystectomy. Hepatobiliary scintigraphy or oral cholecystography can assess the gallbladder function and nonvisualization of gallbladder usually indicates acute or severe chronic cholecystitis. The purpose of this study was to evaluate the role of preoperative hepatobiliary scintigraphy or oral cholecystography in predicting the performance of laparoscopic cholecystectomy. The study group consists of 176 patients who underwent both hepatobiliary scintigraphy with Tc-99m DISIDA and oral choelcystography within one month before laparoscopic cholecystectomy. Nonvisualization of gallbladder was defined as persistent nonvisualization of gallbladder until 4 hours on hepatobiliary scintigraphy or 12 hours on oral cholecystography. Among 176 patients, gallbladder was not visualized in 38 patients on hepatobiliary scintigraphy and 41 patients on oral cholecystography. Concordance rate between hepatobiliary scintigraphy and oral cholecystography was 89.2%. The conversion rate to open cholocystectomy was significantly higher in patients with nonvisualization of gallbladder than in patients with gallbladder higher in patients with nonvisualization of gallbladder visualization (15.8% vs 2.9% on hepatobiliary scintigraphy, 12.2% vs 3.7% on oral cholecystography: p<0.01 and p<0.05 respectively). The operative complication rate was also significantly higher in patients with nonvisualization of gallbladder (13.2% vs 2.9% on hepatobiliary scintigraphy, 14.6% vs 2.2% on oral cholecystography : p<0.01 and p<0.001, respectively). Similarly, operation time was significantly prolonged in patients with nonvisualization of gallbladder (88.8{+-}41.9 min vs 62.5{+-}23.6 min on hepatobiliary scintigraphy : p<0.001, 89.4{+-}41.3 min vs 61.8{+-}22.8 min on oral cholecystography :p<0

  7. The role of hepatobiliary scintigraphy and MR cholangiography in the assessment of bile duct obstruction after biliary surgery

    International Nuclear Information System (INIS)

    Kim, Jae Seung; Moon, Dae Hyuk; Lee, Moon Gyu; Lee, Sung Gyu; Lee, Hee Kyung

    1998-01-01

    The aim of our study was to determine the role of MR cholangiography (MRC) and hepatobiliary scintigraphy (HBS) in the assessemtn of recurrent bile duct obstruction after biliary surgery. Twenty-three patients (15 men and 8 women: mean age 49.8) with post-biliary operation state (16 biliary-enteric anastomoses and seven cholecystectomy) underwent a total of 28 MRC and 28 HBS using Tc-99m DISIDA within 3 days of each other. Interval between surgery and MRC or HBS ranged from 2 wk to 15 yr (median: 14 mon). MRC and HBS were analyzed for the presence of bile duct obstruction. The final diagnoses were cofirmed by percutaneous transhepatic biliary drainage or surgical operation in 11 of 28 cases and by the follow-up clinical course in the rests. Of 14 instances with bile duct obstruction (13 intrahepatic bile duct obstruction and 1 common bile duct obstruction), HBS showed complete intrahepatic bile duct (IHD) obstruction in 7, incomplete IHD obstruction in 5, parenchymal dysfuction in 1, and IHD dilation without obstructon in 1, resulting in sensitivity of 86% (12/14). MRC showed stone in 6, stricture in 4, IHD dilatation in 3, and normal in 1. The sensitivity of MRC was 71% (10/14). Fourteen instances were without obstruction. HBS showed no evidence of obstruction in all 14 instances (specificity 100%). However, stricture on MRC was found in 4 instances, resulting in specificity of 71% (10/14). HBS is useful in the diagnosis of recurrent bile duct obstruction after surgery. MRC is a useful modality for assessing the diagnosis of obstruction itself as well as the cause and location of bile duct obstruction. However, the specificity of MRC appears to be lower because of possible overestimation of stricture

  8. Imaging in hepatobiliary disease

    International Nuclear Information System (INIS)

    Dooley, J.

    1987-01-01

    This book covers the diagnostic and interventional use of imaging techniques in hepatobiliary disease. The first of the book's two sections describes the role of imaging in the diagnostic work up of common clinical syndromes. The second part is concerned with therapy and reviews interventional techniques for hepatobiliary disease

  9. Hepatobiliary sequential scintiscanning

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    Germann, G.; Hottenrott, C.; Maul, F.D.

    1985-01-04

    The duodeno-gastric reflux was evaluated in 33 patients following gastric surgery by functional hepato-biliary scintigraphy. In 16 of 26 patients with gastric resection a reflux was found. The Y-en-Roux and the retrocolic B II resection with Braun's Anastomosis showed the lowest incidence of reflux. The functional scintigraphy permits an objective diagnosis of reflux without provocation by diagnostic manipulations. The high percentage of accuracy in evaluating reflux recommends the scintigraphy as an optimal method in postoperative reflux control.

  10. Gastrointestinal and hepatobiliary radiology

    International Nuclear Information System (INIS)

    Graham, R.N.J.; Perriss, R.W.; Scarsbrook, A.F.

    2006-01-01

    This is the fifth in the series of short reviews of internet-based radiological learning resources and will focus on gastrointestinal (GI) and hepatobiliary radiology. Below are details of a few of the higher quality resources currently available. Most of the sites cater for medical students and trainee or non-specialist radiologists, but may be also be of interest to specialists, especially for use in teaching. Hyperlinks are available in the electronic version of this article and were all active at the time of going to press (May 2006)

  11. Focal nodular hyperplasia of the liver: The role of Nuclear Medicine

    International Nuclear Information System (INIS)

    Von Wenzel, K.S.; Ellmann, A.; Rubow, S.M.

    2002-01-01

    Focal nodular hyperplasia (FNH) is a rare benign hepatic tumour of unknown etiology. Clinically it is described in middle aged females, but it can occur at any age and has been described in children and males. Usually these tumours are asymptomatic and are detected incidentally during ultrasonographic or other diagnostic examinations or at autopsy. FNH may however present with vague or even severe abdominal pain. Histologically a FNH is composed of Kupffer cells, hepatocytes, bile duct elements and fibrous connective tissue. Other types of benign hepatic tumours like hepatic adenomas (HA) need to be distinguished from FNH, as their management differs. Two patients recently presented at Windhoek Hospital with abdominal pain. In both cases Nuclear Medicine investigations, namely Tc-99m colloid liver scintigraphy and hepatobiliary scanning with Tc-99m DISIDA, aided in the diagnosis of focal nodular hyperplasia. This poster will demonstrate the value of Nuclear Medicine investigations in the evaluation of patients with focal nodular hyperplasia

  12. Hepatobiliary sequential scintiscanning

    International Nuclear Information System (INIS)

    Eissner, D.

    1985-01-01

    The main criteria for interpreting hepatobiliary sequential scintiscanning (HBSS) data are given to be the following: (1) In young infants - without previous parenteral feeding - a normal up to a slightly increased activity uptake in the liver, accompanied by lack of activity excretion into the intestine (which requires a 24 - hour scan for detection) is a clear indication of bile duct atresia. However, the same findings can be obtained on very young newborn (up to one week of age) in case of a hepatitis with defined cholestasis. (2) In case of a comparably high activity uptake in the liver together with activity excretion into the intestine, which may be detectable in due time or after a delay (24-hour scan required), bile duct atresia can be excluded, the diagnosis being hepatitis. In general, hepatitis will cause a stronger liver cell damage, which excludes the criterion of activity excretion into the intestine. Similar findings can be obtained on infants with bile duct atresia with previous parenteral feeding. This is why the interpretation of HBSS data can only be effectively carried out in close cooperation with the pediatrician, and on the basis of profound knowledge of the overall clinical state of the infant. (orig.) [de

  13. Hepatobiliary scan in neonatal Jaundice

    International Nuclear Information System (INIS)

    Nahar, Nurun; Hasan, Mizanul; Karim, M.A.

    2002-01-01

    Jaundice is more or less common in newborn babies. Through physiological jaundice is most common cause of neonatal jaundice, possibility of obstructive jaundice especially biliary atresia should be kept in mind. Early diagnosis of biliary atresia followed by surgical treatment can save baby's life. Otherwise death is inevitable due to liver failure. Hepatobiliary scan is the imaging study of choice in neonatal jaundice especially when there is persistent conjugated hyperbilirubinaemia. Total 27 newborn babies of suspected biliary atresia, aged 14 days to 4 months were referred to Institute of Nuclear Medicine for Hepatobiliary scan. All of them had high serum bilirubin ranged from 6.0 mg/dl with an average of 9.35 ng/dl serum bilirubin level. Ultrasonography of hepatobiliary system was performed in 14 cases showing normal sized liver in 4 cases and hepatomegaly in 10 cases. Hepatobiliary scan was done with 99m Tc-Mebrofenin (Br IDA) after preparing the baby with phenobarbitone for 3-5 days. 20 (67%) cases were scan positive suggesting biliary atresia (BA) and 7(27%) cases were scan negative. In BA there will be increased hepatic uptake of the radionuclide without any significant excretion even in 24 hours delayed images. Presence of radiotracer in the bowel exclude the diagnosis of BA. Early diagnosis of biliary atresia is very important because in this condition surgery should be performed early (within 60 days of life). Studies suggest that hepatobiliary scan after hepatic stimulation with phenobarbitone for a period of 3-5 days is highly accurate for differentiating biliary atresia from other causes of neonatal jaundice. It is very important to perform hepatobiliary scan in a case of neonatal jaundice to exclude biliary atresia for the sake of baby's life.(author)

  14. Understanding and controlling hepatobiliary function

    NARCIS (Netherlands)

    Elferink, Ronald P. J. Oude

    2002-01-01

    Over the past decade, enormous progress has been made in identifying the mechanisms that underlie hepatobiliary excretion. A set of transport proteins mediates the canalicular transport of most important bile constituents. With the discovery of these transporter genes, the mechanism of bile

  15. Dynamic hepatobiliary scintigraphy using EHIDA and HIDA

    International Nuclear Information System (INIS)

    Radtke, J.

    1980-01-01

    Data of 9 healthy test persons studied on an empty stomach using EHIDA and HIDA were analyzed in order to determine the influence of a region of interest on the shape of heart and liver function curves. The kinetics of EHIDA and HIDA in these 9 test persons showed marked differences in the passage of the hepatobiliary system and in plasma kinetics but not in renal urinary excretion. Further, functional histograms of the heart, liver, gall bladder, and duodenum of 25 healthy patients were established after meals and administration of EHIDA or HIDA. The parameters derived from these functional histograms did not differ significantly from the data of the test persons examined on an empty stomach. Also, the time interval since the last meal was found to be negligible. In 3 healthy test persons, the injected concentration of the radiopharmaceutical was increased to 8 times the standard dose. There was no significant change in HIDA kinetics except for a more rapid excretion into the intestine. In 7 healthy test persons, a comparative study was carried out of HIDA kinetics with and without decholine premedication. The normal collectives were compared with 118 patients with different morphological and functional findings. However, this method was not superior to sequential scintiscanning. Differential diagnosis of parenchymal and obstructive jaundice using the liver function curve is possible only in the acute stage in consideration of the analogue scintiscanning images. The data of the 9 healthy test persons were also used to assess the usefulness of EDP in eliminating statistical variations of the functional curves and in determining descriptive parameters. Curve smoothing by data bounding resulted in reproducible values, and the systematic error introduced by estination was avoided. (orig./MG) [de

  16. Hepatobiliary manifestations of gastrointestinal and nutritional disorders.

    Science.gov (United States)

    Samarasena, Jason B; Hu, Ke-Qin

    2011-02-01

    Hepatobiliary manifestations of gastrointestinal and nutritional disorders can occur as part of the clinical spectrum of the underlying disease or as a consequence of the treatment of the disease. This article reviews aspects of pathogenesis, diagnosis, and management of hepatobiliary manifestations associated with a selection of gastrointestinal and nutritional disorders including inflammatory bowel disease, celiac disease, Whipple's disease, and parenteral nutrition associated disorders. Copyright © 2011 Elsevier Inc. All rights reserved.

  17. Emergency surgeon-performed hepatobiliary ultrasonography.

    LENUS (Irish Health Repository)

    Kell, M R

    2012-02-03

    BACKGROUND: Acute hepatobiliary pathology is a common general surgical emergency referral. Diagnosis requires imaging of the biliary tree by ultrasonography. The accuracy and impact of surgeon-performed ultrasonography (SUS) on the diagnosis of emergent hepatobiliary pathology was examined. METHODS: A prospective study, over a 6-month period, enrolled all patients with symptoms or signs of acute hepatobiliary pathology. Patients provided informed consent and underwent both SUS and standard radiology-performed ultrasonography (RUS). SUS was performed using a 2-5-MHz broadband portable ultrasound probe by two surgeons trained in ultrasonography, and RUS using a 2-5-MHz fixed unit. SUS results were correlated with those of RUS and pathological diagnoses. RESULTS: Fifty-three consecutive patients underwent 106 ultrasonographic investigations. SUS agreed with RUS in 50 (94.3 per cent) of 53 patients. SUS accurately detected cholelithiasis in all but two cases and no patient was inaccurately diagnosed as having cholelithiasis at SUS (95.2 per cent sensitivity and 100 per cent specificity). As an overall complementary diagnostic tool SUS provided the correct diagnosis in 96.2 per cent of patients. Time to scan was significantly shorter following SUS (3.1 versus 12.0 h, P < 0.05). CONCLUSION: SUS provides a rapid and accurate diagnosis of emergency hepatobiliary pathology and may contribute to the emergency management of hepatobiliary disease.

  18. Hepatobiliary scintigraphy in current pediatric practice

    Energy Technology Data Exchange (ETDEWEB)

    Roca, I. [Division of Nuclear Medicine `HGU` Vall d`Hebron, Barcelona (Spain); Ciofetta, G. [Division of Nuclear Medicine `HGU` Vall d`Hebron, Barcelona (Spain)]|[Rome, Univ. `La Sapienza` (Italy). Pediatric Clinic. Laboratory of Pediatric Nuclear Medicine

    1998-06-01

    Hepatobiliary scintigraphy is the only non-invasive technique providing real-time assessment of hepatocytes function and bile progression from the liver to the intestine; for this reason it is of great importance in the study of jaundice and many other disorders of the liver and the biliary tract in children. Ultrasonography is the initial method of evaluating the intra- and extrahepatic bile ducts dilatation: the differential diagnosis between biliary atresia and neonatal hepatitis cannot however be done without hepatobiliary scintigraphy. Cystic fibrosis patients also require hepatobiliary scintigraphy; liver and biliary tract disease can really occur independently of the underlying disease severity and the presence of steatorrhoea. Hepatobiliary imaging in children who have undergone liver transplantation is of major importance; it can assess vascularity, parenchymal function biliary drainage, possible presence of a bile leak and obstruction; it has very good sensitivity and specificity for the detection of biliary leak and biliary stricture. Due to those important clinical conditions being studied in pediatrics, both qualitative and quantitative information (functional indices obtained from radioactivity/ time curve analysis) need to be extracted; in addition, SPECT acquisition allows more accurate evaluation of abdominal activity during the excretory phase.

  19. Hepatobiliary scintigraphy in current pediatric practice

    International Nuclear Information System (INIS)

    Roca, I.; Ciofetta, G.; Rome, Univ. 'La Sapienza'

    1998-01-01

    Hepatobiliary scintigraphy is the only non-invasive technique providing real-time assessment of hepatocytes function and bile progression from the liver to the intestine; for this reason it is of great importance in the study of jaundice and many other disorders of the liver and the biliary tract in children. Ultrasonography is the initial method of evaluating the intra- and extrahepatic bile ducts dilatation: the differential diagnosis between biliary atresia and neonatal hepatitis cannot however be done without hepatobiliary scintigraphy. Cystic fibrosis patients also require hepatobiliary scintigraphy; liver and biliary tract disease can really occur independently of the underlying disease severity and the presence of steatorrhoea. Hepatobiliary imaging in children who have undergone liver transplantation is of major importance; it can assess vascularity, parenchymal function biliary drainage, possible presence of a bile leak and obstruction; it has very good sensitivity and specificity for the detection of biliary leak and biliary stricture. Due to those important clinical conditions being studied in pediatrics, both qualitative and quantitative information (functional indices obtained from radioactivity/ time curve analysis) need to be extracted; in addition, SPECT acquisition allows more accurate evaluation of abdominal activity during the excretory phase

  20. Study of a new hepatobiliary radiotracer: sup(99m)Tc diethyl IDA. Its value in the diagnosis of cholestasis

    International Nuclear Information System (INIS)

    Roques, J.F.

    1979-01-01

    This work examines a new means of investigation: Technetium 99 (2,6 diethyl acetanilido) imino-diacetic acid, or HEPATOBIDA, hepatobiliary scintigraphy. A survey of different scintigraphic techniques is necessary. At first the kinetic study of hepatobiliary radiotracers was carried out with multiprobe systems giving quantitative information on the various organs or pools concerned. With the appearance of the scintillation camera it became possible to obtain not only quantitative data but also topographical and morphological information. Since 1976 the derivatives of iminodiacetic acid have been widely adopted, possessing features most closely resembling those of the ideal hepatobiliatropic molecules. Examinations have been performed at the Angers Radioisotopes Service with the diethyl derivative or HEPATOBIDA (Nuclear Solca Lab.) The results recorded in a group of cholestasis patients are studied, with normal data supplied by a set of 8 reference subjects free from hepatobiliary diseases [fr

  1. Hepatobiliary Disorders in Celiac Disease: An Update

    Directory of Open Access Journals (Sweden)

    Kaushal K. Prasad

    2011-01-01

    Full Text Available This communication reviews recent literature and summarizes hepatobiliary abnormalities that may complicate the clinical course of celiac disease. A wide spectrum of hepatobiliary diseases has been described, including asymptomatic elevations of liver enzyme levels, nonspecific hepatitis, nonalcoholic fatty liver disease, and autoimmune and cholestatic liver disease. Moreover, in the majority of patients, liver enzyme levels will normalize on a gluten-free diet. In addition, celiac disease may be associated with rare hepatic complications, such as hepatic T-cell lymphoma. Because many celiac patients do not have overt gastrointestinal symptoms, a high index of suspicion is required. Simple methods of detecting celiac disease such as serum antibody tests help in the early identification of the disease, thus preventing serious complications of the disorder. The IgG DGP antibody test and IgA tTG antibody test used in combination are an excellent screening test for suspected cases of celiac disease.

  2. Functional hepatobiliary MR imaging in children

    Energy Technology Data Exchange (ETDEWEB)

    Tamrazi, Anobel; Vasanawala, Shreyas S. [Stanford University, Department of Radiology, Stanford, CA (United States)

    2011-10-15

    Clinical application efforts for the hepatocyte-specific MRI contrast agent gadolinium ethoxybenzyl diethylenetriamine pentaacetic acid (Gd-EOB-DTPA) have mainly been directed toward detection and characterization of various hepatic masses in the adult population. Here we report our initial experience with Gd-EOB-DTPA for evaluating congenital and acquired hepatobiliary pathologies in the pediatric population. Twenty-one consecutive children receiving Gd-EOB-DTPA for functional hepatobiliary evaluation at our institution were retrospectively identified with IRB approval. The use of Gd-EOB-DTPA was classified in each case as definite, potential, or no clinical utility, focusing on the clinical value gained beyond traditional noncontrast fluid-sensitive MR cholangiopancreatography (FS-MRCP) and other imaging modalities. Definite added value of Gd-EOB-DTPA was found in 12 patients, with potential value in 4 patients, and no value in 5 patients. Benefit was seen in cases of iatrogenic and non-iatrogenic biliary strictures, perihepatic fluid collections for biliary leak, hepatobiliary dysfunction in the absence of hyperbilirubinemia, and in the functional exclusion of cystic duct occlusion that can be seen in acute cholecystitis. This is the first reported series of children with Gd-EOB-DTPA and this early work suggests potential pediatric applications. (orig.)

  3. Role of hepatobiliary scintigraphy in obstructive jaundice

    International Nuclear Information System (INIS)

    Jadhav, Praveen; Shikare, Shekhar; Tilve, Gundu

    1990-01-01

    Hepatobiliary scintigraphy is a very useful investigation in cholestatic jaundice, especially when serum bilirubin is less than 20 mg %. It is particularly useful to diagnose early biliary obstruction, to quantitate biliary obstruction with measurement of hepatic and gall bladder bile excretion rate, to determine the urgency of therapeutic procedure and to evaluate the effect of therapy in all these cases. In these cases other investagations like ultrasonography are less useful as compared to scintigraphy which has a high index of sensitivity. In this study, comparative analysis of 32 cases of cholestatic jaundice is presented. (author). 12 refs ., 4 tabs

  4. Hepatobiliary Cystadenoma Revealed by a Jaundice: A Case Report

    Directory of Open Access Journals (Sweden)

    Taoufiq Harmouch

    2011-01-01

    Full Text Available Introduction. Hepatobiliary cystadenomas are rare benign cystic tumors and have a potential for recurrence and malignant transformation. The diagnosis may be very difficult because of absence of typical imaging feature in some cases. Case Presentation. In this paper, the authors discuss a 57-year-old woman who presented a jaundice related to hepatobiliary cystadenoma. Biological and radiological examinations have led to surgery, and the diagnosis is made after a histological examination of surgical specimens. Conclusion. This observation illustrates a hepatobiliary cystadenoma revealed by jaundice. Histology examination contributed to diagnosis. The authors discussed the mechanisms of biliary obstruction and differential diagnoses through a review of the literature.

  5. Obstructive jaundice due to hepatobiliary cystadenoma or cystadenocarcinoma

    NARCIS (Netherlands)

    Erdogan, Deha; Busch, Olivier R. C.; Rauws, Erik A. J.; van Delden, Otto M.; Gouma, Dirk J.; van-Gulik, Thomas M.

    2006-01-01

    Hepatobiliary cystadenomas (HBC) and cystadenocarcinomas are rare cystic lesions. Most patients with these lesions are asymptomatic, but presentation with obstructive jaundice may occur. The first patient presented with intermittent colicky pain and recurrent obstructive jaundice. Imaging studies

  6. Hepato-biliary clinical trials and their inclusion in the Cochrane Hepato-Biliary Group register and reviews

    DEFF Research Database (Denmark)

    Klingenberg, Sarah Louise; Nikolova, Dimitrinka; Alexakis, Nicholas

    2011-01-01

    The Cochrane Hepato-Biliary Group (CHBG) is one of the 52 collaborative review groups within The Cochrane Collaboration. The activities of the CHBG focus on collecting hepato-biliary randomized clinical trials (RCT) and controlled clinical trials (CCT), and including them in systematic reviews wi...... with meta-analyses of the trials. In this overview, we present the growth of The CHBG Controlled Trials Register, as well as the systematic reviews that have been produced since March 1996....

  7. Peritoneal and pleural fluids may appear hyperintense on hepatobiliary phase using hepatobiliary MR contrast agents.

    Science.gov (United States)

    Ciolina, Maria; Di Martino, Michele; Bruno, Onorina; Pommier, Romain; Vilgrain, Valérie; Ronot, Maxime

    2018-01-26

    To describe the effect of hepatobiliary-specific MR imaging contrast agent (HBCA) administration on the signal intensity of peritoneal and pleural fluid effusions on T1-weighted MR images. From October 2015 to May 2016 139 patients (mean 60±10 years old, 69 % males) with peritoneal or pleural effusions without biliary leakage who underwent HBCA-MRI (Gd-BOPTA or Gd-EOB-DTPA) at 1.5T and 3T were included from two centres. The fluid signal intensity was classified as hypo/iso/hyperintense before/after HBCA administration. The relative signal enhancement (RE) was calculated. On hepatobiliary phase (HBP), peritoneal fluids appeared hyper/isointense in 88-100 % and pleural effusions in 100 % of the patients following Gd-BOPTA administration. All fluids remained hypointense following Gd-EOB-DTPA. The signal intensity of fluids increased with both HBCA but RE was significantly higher following Gd-BOPTA (p=0.002 to fluids). The signal intensity of pleural and peritoneal fluids progressively increases following HBCA administration in the absence of biliary leakage. Due to its later hepatobiliary phase, this is more pronounced after Gd-BOPTA injection, leading to fluid hyperintensity that is not observed after Gd-EOB-DTPA injection. • Fluids appear hyper/isointense on HBP in most patients after Gd-BOPTA injection. • Fluids remain hypointense on HBP after Gd-EOB-DTPA injection. • RE of fluids increases with time after liver-specific Gd injection. • RE of fluids is higher in patients with chronic liver disease.

  8. Hepatic clearance mechanism of /sup 99m/Tc-HIDA and its effect on quantitation of hepatobiliary function concise communication

    International Nuclear Information System (INIS)

    Harvey, E.; Loberg, M.; Ryan, J.; Sikorski, S.; Faith, W.; Cooper, M.

    1979-01-01

    Parameters affecting the hepatobiliary clearance of /sup 99m/Tc N(2,6-dimethylphenylcarbamoylmethyl) iminodiacetic acid (Tc-HIDA) were evaluated in dogs. Competitive clearance studies were performed with Tc-HIDA after infusion to plasma saturation levels of an anion, sodium sulfobromophthalein (BSP), and a cation, oxyphenonium. The results demonstrated that Tc-HIDA is transported through hepatocytes by a carrier-mediated organic-anion pathway. The data are consistent with an alteration of the elimination kinetics of Tc-HIDA induced by elevations in the serum bilirubin level, and it is predicted that serum bilirubin at some increased concentration will dominate the distribution and elimination kinetics of Tc-HIDA independently of hepatobiliary status. A quantitative description of liver function in terms of regional distribution and elimination rate constants will require either a pharmacokinetic model that expressly includes the effects of bilirubin from transport binding sites, or the development of new hepatobiliary agents that use a different clearance mechanism from that used by bilirubin

  9. Hepatobiliary disease in children and adolescents with cystic fibrosis.

    Science.gov (United States)

    Nascimento, Fernanda de S; Sena, Nelson A; Ferreira, Tatiane da A; Marques, Cibele D F; Silva, Luciana R; Souza, Edna Lúcia

    2017-09-07

    The aims of the study were to determine the frequency of hepatobiliary disease in patients with cystic fibrosis and to describe the sociodemographic, clinical, and laboratory profile of these patients. This was a retrospective, descriptive, and analytical study of 55 patients diagnosed with cystic fibrosis, aged between 3 months and 21 years, followed-up from January 2008 to June 2016 in a referral center. Medical records were consulted and sociodemographic, clinical and laboratory data, including hepatobiliary alterations, imaging studies, genetic studies, liver biopsies, and upper digestive endoscopies were registered. Hepatobiliary disease was diagnosed in 16.4% of the patients and occurred as an initial manifestation of cystic fibrosis in 55.6% of these cases. The diagnosis of hepatopathy occurred before or concomitantly with the diagnosis of cystic fibrosis in 88.9% of the children. All patients with hepatobiliary disease were considered non-white, with a predominance of females (77.8%) and median (IQR) of 54 (27-91) months. Compared with the group without hepatobiliary disease, children with liver disease had a higher frequency of severe mutations identified in the CFTR gene (77.8% vs. 39.6%, p=0.033) and severe pancreatic insufficiency (88.9% vs. 31.6%, p=0.007). The frequency of hepatobiliary disease was high, with a very early diagnosis of the disease and its complications in the studied series. A statistical association was observed between the occurrence of hepatobiliary disease and the presence of pancreatic insufficiency and severe mutations in the CFTR gene. It is emphasized that cystic fibrosis is an important differential diagnosis of liver diseases in childhood. Copyright © 2017 Sociedade Brasileira de Pediatria. Published by Elsevier Editora Ltda. All rights reserved.

  10. Application of da Vinci surgical robotic system in hepatobiliary surgery

    Directory of Open Access Journals (Sweden)

    Chen Jiahai

    2018-01-01

    Full Text Available The development of minimally invasive surgery has brought a revolutionary change to surgery techniques, and endoscopic surgical robots, especially Da Vinci robotic surgical system, has further broaden the scope of minimally invasive surgery, which has been applied in a variety of surgical fields including hepatobiliary surgery. Today, the application of Da Vinci surgical robot can cover most of the operations in hepatobiliary surgery which has proved to be safe and practical. What’s more, many clinical studies in recent years have showed that Da Vinci surgical system is superior to traditional laparoscopy. This paper summarize the advantage and disadvantage of Da Vinci surgical system, and outlines the current status of and future perspectives on the robot-assisted hepatobiliary surgery based on the cases reports in recent years of the application of Da Vinci surgical robot.

  11. Evaluation of six new /sup 99m/Tc-IDA agents for hepatobiliary imaging

    Energy Technology Data Exchange (ETDEWEB)

    Chervu, L.R.; Joseph, J.A.; Chun, S.B.; Rolleston, R.E.; Synnes, E.I.; Thompson, L.M.; Aldis, A.E.; Rosenthall, L.

    1988-10-01

    IDA derivatives of three substituted benzothiazol, and two substituted chlorophenyl and one substituted pyrazoline compounds have been labeled with /sup 99m/Tc and screened with four rat models with hepatocellular dysfunction manifesting varying degrees of change of liver architecture and hepatocellular damage associated with an active parenchymal destruction, fatty metamorphosis and cirrhosis. Organ distribution studies at 1 h postinjection have been compared in normal and diseased animal models for each agent labeled with /sup 99m/Tc and with /sup 99m/Tc-Disofenin (Disida) and Lidofenin (Hida) and /sup 131/I-Rose Bengal. From the data obtained with the six new IDA derivatives, the distribution kinetics of /sup 99m/Tc-Arclophenin, (N-N'-2-benzoyl-4-chlorophenyl)carbamoylmethyl) imino diacetic acid (Phenida), are closely comparable to /sup 99m/Tc-Disofenin in all animal models. Crossover patient studies (n = 14) for clinical evaluation of /sup 99m/Tc-Arclophenin vs /sup 99m/Tc-Disofenin indicate the close similarity of the 2 agents with regard to blood pool retention, gross liver/heart ratios and liver washout, suggesting Arclophenin as a suitable agent for hepatobiliary function studies. The impaired hepatocellular animal models presented should serve for fast screening of hepatobiliary agents and enable comparison of a series of closely related compounds.

  12. Etiology of the obstructive pattern in hepatobiliary imaging

    Energy Technology Data Exchange (ETDEWEB)

    Hughes, K.S.; Marrangoni, A.G.; Turbiner, E.

    1984-04-01

    The records of all patients undergoing hepatobiliary imaging with technetion radioisotopes at our hospital from January 1980 to March 1983 were reviewed and 29 scans met the criteria for a pattern consistent with complete biliary tract obstruction. Biliary tract obstruction (due to choledocholithiasis, primary or secondary carcinoma involving the common bile duct, and pancreatitis) was documented in 24 of these patients. However, the remaining five patients had a patent common bile duct, and the etiologic factor was intrahepatic cholestasis secondary to sepsis in four and peritonitis in one. A classification of altered biliary dynamics in hepatobiliary imaging, which is based on the classification of jaundice, is proposed.

  13. Accuracy of Hepatobiliary Scintigraphy after Liver Transplantation and Liver Resection

    Directory of Open Access Journals (Sweden)

    Manuel Eckenschwiller

    2016-01-01

    Full Text Available Background and Aims. Biliary complications are the most frequent complications after common liver surgeries. In this study, accuracy of hepatobiliary scintigraphy (HBS and impact of hyperbilirubinemia were evaluated. Methods. Between November 2007 and February 2016, 131 patients underwent hepatobiliary scintigraphy after having liver surgery. 39 patients with 42 scans after LTX (n=13 or hepatic resection (n=26 were evaluated in the study; 27 were male, with mean age 60 years. The subjects underwent hepatobiliary scintigraphy with Tc-99m labeled Mebrofenin. The results were compared to ERCP as gold standard performed within one month after HBS. We calculated sensitivity, specificity, PPV, and NPV. We compared LTX patients to patients with other liver surgeries. Furthermore the influence of hyperbilirubinemia on HBS scans was evaluated. Results. HBS always provided the correct diagnosis in cases of bile leak in the liver-resected group (14/14. Overall diagnostic accuracy was 76% (19/25 in this group and 54% (7/13 in the LTX group. False negative (FN diagnoses occurred more often among LTX patients (p=0.011. Hyperbilirubinemia (>5 mg/dL significantly influenced the excretion function of the liver, prolonging HBS’s time-activity-curve (p=0.001. Conclusions. Hepatobiliary scintigraphy is a reliable tool to detect biliary complications, but reduced accuracy must be considered after LTX.

  14. PIPIDA excretory scintigraphy in the diagnosis of hepatobiliary disorders

    International Nuclear Information System (INIS)

    Pelot, D.; Berk, J.E.; Wistow, B.W.; Morton, M.E.

    1981-01-01

    The diagnostic accuracy of hepatobiliary radionuclide imaging using 99 mTC-labeled para-isopropyl acetanilido-iminodiacetic acid ( 99 mTc-PIPIDA) in patients with hepatobiliary disorders was assessed in 50 patients. Thirty of the study group were jaundiced; the remaining 20 had other clinical features suggestive of some hepatobiliary disorder. The findings using PIPIDA proved to be correct in 22 (73%) of the 30 jaundiced patients and in 18 (90%) of 20 patients without jaundice. There appears to be a close relationship between the diagnostic accuracy of the test and the level of serum bilirubin. Thus, the diagnosis indicated by the PIPIDA test was correct in 30 (88%) of 34 patients in whom the serum bilirubin was less than 5 mg./dl. but only in 10 (62%) of 16 patients whose serum bilirubin exceeded 5 mg./dl. It is concluded from these observations that: 1. PIPIDA is diagnostically useful in the evaluation of hepatobiliary disorders, especially when the serum bilirubin is less than 5 mg./dl. and 2. the accuracy of this test is not absolute and the findings are not always definitive

  15. Radiological findings of intraparenchymal liver Ascaris (hepatobiliary ascariasis)

    Energy Technology Data Exchange (ETDEWEB)

    Akata, D.; Oezmen, M.N.; Kaya, A.; Akhan, O. [Dept. of Radiology, Hacettepe University School of Medicine, Ankara (Turkey)

    1999-02-01

    Ascariasis is a well-known cause of acute cholangitis and cholecystitis; however, very rarely do worms penetrate and colonize the liver parenchyma. Here we present the unique radiological demonstration (US, CT and ERCP) of hepatobiliary ascariasis in which worm was first alive in the parenchyma of the liver and subsequently died and formed liver abscess. (orig.) (orig.) With 3 figs., 8 refs.

  16. Indocyanine green labeled with 123I for dynamic studies of the hepato-biliary system

    International Nuclear Information System (INIS)

    Lambrecht, R.M.; Ansari, A.N.; Wolf, A.P.; Atkins, H.L.

    1975-01-01

    This report summarizes the results to develop an iodine-123 labeled agent for dynamic studies of the hepato-biliary system. Iodine-123 is an ideal nuclide for radiopharmaceuticals, because of its short half-life (T/sub 1 / 2 / = 13.3 hr); its decay with a high abundance (83%) of 159 keV photons; and the reduced patient radiation exposure (a factor of 100 less than iodine-131). Indocyanine green, a tricarbanocyanine dye, was introduced by Heseltine and co-workers in 1956, has several characteristics which suggested that iodine-123 labeled ICG might be potentially useful for hepatic functional evaluation. The plasma clearance and biliary excretion kinetics of 123 I-ICG (in dogs) will be compared to 131 I-rose bengal and bromosulphalein labeled with iodine-125

  17. Robotic hepatobiliary surgery: update on the current status.

    Science.gov (United States)

    Carr, A D; Ali, M R; Khatri, V P

    2013-10-01

    An update on the current status of robotic hepatobiliary surgery based on a review of the available literature. A literature search was performed using the PubMed database with search phrases "robotic hepatectomy", "robotic liver resection", "robotic liver surgery", "robotic hepatobiliary surgery", and "robotic biliary reconstruction". We selected articles with high volume case series or case controlled series. As a result of our literature search we will focus on the 9 major articles on robotic liver resection (RLR) with 235 patients undergoing RLR for a total of 244 liver resections. In addition a brief update on robotic biliary reconstruction will also be presented based on the above articles and recent review articles. Indications for robotic liver resection included both benign (N.=72, 29.5%) and malignant disease (N.=172, 70.5%). The most common indication was colorectal liver metastasis (N.=87, 50.6%) and hepatocellular carcinoma (N.=57, 33%). The most common type of resection was subsegmental (N.=55, 22.5%), with a significant number of major hepatectomies (N.=80, 32.8%). Overall conversion rate was 7.8%, with majority converted to open (N.=18) and one converted to hand assisted. The overall complication rate was 11.8% (N.=29). No perioperative mortality was reported. Preliminary results show that robotic assisted laparoscopic hepatobiliary surgery has materialized as a new technique that combines the advantages of laparoscopy with the dissection, suturing and articulation of robotics. This more closely approximates open surgery. The preliminary data demonstrates that RLR can be applied in major hepatobiliary centers safely. Future comparative studies are needed to determine if this is of significant benefit over current open techniques.

  18. Percutaneous cholecystocentesis in cats with suspected hepatobiliary disease.

    Science.gov (United States)

    Byfield, Victoria L; Callahan Clark, Julie E; Turek, Bradley J; Bradley, Charles W; Rondeau, Mark P

    2017-12-01

    Objectives The objective was to evaluate the safety and diagnostic utility of percutaneous ultrasound-guided cholecystocentesis (PUC) in cats with suspected hepatobiliary disease. Methods Medical records of 83 cats with suspected hepatobiliary disease that underwent PUC were retrospectively reviewed. Results At the time of PUC, at least one additional procedure was performed in 79/83 cats, including hepatic aspiration and/or biopsy (n = 75) and splenic aspiration (n = 18). Complications were noted in 14/83 cases, including increased abdominal fluid (n = 11), needle-tip occlusion (n = 1), failed first attempt to penetrate the gall bladder wall (n = 1) and pneumoperitoneum (n = 1). There were no reports of gall bladder rupture, bile peritonitis or hypotension necessitating treatment with vasopressor medication. Blood products were administered to 7/83 (8%) cats. Seventy-two cats (87%) survived to discharge. Of the cats that were euthanized (9/83) or died (2/83), none were reported as a definitive consequence of PUC. Bacteria were identified cytologically in 10/71 samples (14%); all 10 had a positive aerobic bacterial culture. Bile culture was positive in 11/80 samples (14%). Of the cases with a positive bile culture, cytological description of bacteria corresponded to the organism cultured in fewer than 50% of cases. The most common cytologic diagnosis was hepatic lipidosis (49/66). The most common histopathologic diagnosis was cholangitis (10/21). Conclusions and relevance PUC was safe in this group of cats with suspected hepatobiliary disease. Complications were likely associated with ancillary procedures performed at the time of PUC. Bile analysis yielded an abnormal result in nearly one-third of cats with suspected hepatobiliary disease. Complete agreement between bile cytology and culture was lacking. Further evaluation of the correlation between bile cytology and bile culture is warranted.

  19. Tc99m- hepatobiliary iminodiacetic acid (HIDA) scintigraphy in clinical practice

    International Nuclear Information System (INIS)

    Lambie, H.; Cook, A.M.; Scarsbrook, A.F.; Lodge, J.P.A.; Robinson, P.J.; Chowdhury, F.U.

    2011-01-01

    There have been evolutionary changes in the management of pathological conditions of the hepatobiliary system over recent years, particularly with an increasing emphasis on modern hepatobiliary surgical techniques. Concurrent advances have occurred in imaging technology and availability, leading to a greater use of ultrasound, multidetector computed tomography (CT), and magnetic resonance imaging (MRI) in the primary evaluation of hepatobiliary disease. Radionuclide imaging using technetium 99m (Tc 99m ) hepatobiliary iminodiacetic acid (HIDA) derivatives is an established technique that complements morphological imaging, providing valuable functional information in both pre- and postoperative evaluation of patients with suspected or known hepatobiliary disease. This review discusses the current clinical indications for Tc 99m HIDA scintigraphy using clinical cases to demonstrate how this technique continues to play a valuable diagnostic role in the assessment of the functional integrity of the hepatobiliary system.

  20. Value of an hepatobiliary imaging agent for diagnosing hepatoma. Example of diethyl-IDA

    Energy Technology Data Exchange (ETDEWEB)

    Bourguet, P.; Estable, P.; Herry, J.Y.

    1985-01-01

    A comparative study was performed using two hepatic tracers, a Tc 99m labelled colloid and an hepatobiliary agent Tc 99m labelled diethyl-IDA. In some patients with isolated primary hepatocarcinoma the uptake of the hepatobiliary agent was observed but the colloid was not taken up. In the contrary, the hepatobiliary agent has proved to be of limited value for the diagnosis of hepatomas coexisting with cirrhosis and for the detection of secondary hepatocarcinoma.

  1. The pattern of hepatobiliary complications among Egyptian sickle cell disease children

    Directory of Open Access Journals (Sweden)

    Dalia A. Saied

    2017-07-01

    Conclusion: Hepatobiliary complications are frequent among sickle cell disease children especially gallbladder diseases. Repeated clinical and ultrasound screening is needed for early detection and treatment of these complications.

  2. Assessment of Future Remnant Liver Function Using Hepatobiliary Scintigraphy in Patients Undergoing Major Liver Resection

    NARCIS (Netherlands)

    de Graaf, W.; van Lienden, K.P.; Dinant, S.; Roelofs, J.J.T.H.; Busch, O.R.C.; Gouma, D.J.; Bennink, R.J.; van Gulik, T.M.

    2010-01-01

    Tc-99m-mebrofenin hepatobiliary scintigraphy (HBS) was used as a quantitative method to evaluate liver function. The aim of this study was to compare future remnant liver function assessed by Tc-99m-mebrofenin hepatobiliary scintigraphy with future remnant liver volume in the prediction of liver

  3. Delayed hepatobiliary imaging in the diagnosis of hepatocellular carcinoma

    International Nuclear Information System (INIS)

    Chen, S.; Ma, Z.; Tang, Z.

    2000-01-01

    In recent years, the use of ultrasonography (US), X-CT and MRI has reduced the employment of isotopic explorations in the detection of hepatocellular carcinoma (HCC). But sometime the results of US, X-CT or MRI were different and diagnosis was very difficult. This present investigation was aimed to assess the usefulness of delayed hepatobiliary imaging in the diagnosis of HCC in these patients. Forty-eight patients consisting of 33 males and 15 females were entered into the research protocol. The mean age was 46 yr old (range 12-71 yr old). All of the patients were performed by surgery and verified histologically after nuclear examination. The subject was in a supine position under a gamma camera (Elscint, Apex Ap-6) and 555 MBq of Tc-99m-PMT were injected intravenously. The initial scinphotos obtained within 1 min after injection were used to image the blood pool phase. Subsequently, hepatic scans were obtained at 5 min, 1,2 and 5 hr. Anterior, right lateral and posterior hepatic images were recorded. According to the radioactive uptake by the lesion in delayed phase, the negative (no or minor uptake), positive (equal or greater uptake) or very strong positive (almost equal to the activity, of gallbladder) were judged. The positive were considered as diagnostic of HCC. And the very strong positive, were considered as diagnostic of benign hepatoma, such as adenoma or FNH. Thirty-seven of the forty-eight patients were HCC based on histology. Delayed imaging revealed increased or equilibrated uptake of radioactivity by the tumors in 22 of 37 patients with hepatocellular carcinoma. The sensitivity was 59.5%. One patient final diagnosis based on histology was focal nodular regenerative hyperplasia, and only the diagnosis with delayed hepatobiliary imaging before surgery was correct. Compared with US, X-CT and MRI, delayed hepatobiliary imaging had the highest specificity for diagnosis of hepatocellular carcinoma. In recent group, the specificity of Tc-99m-PMT delayed

  4. Analysis of serum corticosteroid-induced alkaline phosphatase isoenzyme in dogs with hepatobiliary diseases.

    Science.gov (United States)

    Kojima, K; Ohno, K; Kanemoto, H; Goto-Koshino, Y; Fukushima, K; Tsujimoto, H

    2017-05-01

    To reveal the relationship between canine corticosteroid-induced alkaline phosphatase isoenzyme activity and hepatobiliary diseases. Retrospective analysis of the relationship between serum corticosteroid-induced alkaline phosphatase activity and diagnosis, serum cortisol concentration and alanine transferase activity in dogs with hepatobiliary diseases. Dogs with a history of glucocorticoid administration were excluded. Seventy-two dogs with hepatobiliary diseases were analysed. The serum corticosteroid-induced alkaline phosphatase concentration was increased in dogs with hepatobiliary diseases. There was no correlation between serum cortisol concentration and serum corticosteroid-induced alkaline phosphatase percentage or activity. Dogs with hepatobiliary disease can exhibit high serum alkaline phosphatase activity even if the dogs have not been administrated glucocorticoids and the serum cortisol concentration is normal. © 2017 British Small Animal Veterinary Association.

  5. Specific diagnosis of hepatocellular carcinoma by delayed hepatobiliary imaging

    Energy Technology Data Exchange (ETDEWEB)

    Hasegawa, Y.; Nakano, S.; Ibuka, K.; Hashizume, T.; Noguchi, A.; Sasaki, Y.; Imaoka, S.; Fujita, M.; Kawamoto, S.; Kasugai, H.

    1986-01-15

    For assessment of the value of delayed hepatobiliary imaging with technetium 99m (/sup 99m/Tc)-(Sn)-N-pyridoxyl-5-methyltryptophan (/sup 99m/Tc-PMT) for specific diagnosis of hepatocellular carcinoma, 88 patients with various malignant and benign liver diseases (49 with hepatocellular carcinoma, 4 with cholangiocellular carcinoma, 10 with metastatic liver carcinoma, 2 with liver cysts, 2 with liver hemangioma, 1 with liver abscess, 2 with intrahepatic lithiasis, 12 with liver cirrhosis, and 6 with chronic hepatitis) were studied. In 20 (41%) of the 49 patients with hepatocellular carcinoma, greater uptake of /sup 99m/Tc-PMT by the tumor than by the surrounding liver tissue was seen in delayed hepatobiliary images, whereas in eight patients (16%), equilibrated uptake was seen. No increased uptake of the radioisotope by hepatic lesions was seen in 21 patients with localized liver diseases other than hepatoma. Moreover, in 18 patients with diffuse liver diseases, no focal accumulation of the radioisotope was seen in delayed /sup 99m/Tc-PMT images. In addition, of 28 patients with hepatocellular carcinoma in whom the serum alpha-fetoprotein level showed little or no increase, 12 showed increased uptake of /sup 99m/Tc-PMT by the tumor. In assessing delayed /sup 99m/Tc-PMT images, however, it was necessary to consider following complications: accumulation of tracer in obstructed and dilated biliary trees; retention of radioactivity in nonneoplastic liver tissues; difficulties in evaluating /sup 99m/Tc-PMT uptake by small hepatic tumors; overlapping of radioactivity in the gut and gallbladder in delayed /sup 99m/Tc-PMT images of tumors. This study indicates that delayed /sup 99m/Tc-PMT images can be useful in the diagnosis of hepatocellular carcinoma.

  6. Specific diagnosis of hepatocellular carcinoma by delayed hepatobiliary imaging

    International Nuclear Information System (INIS)

    Hasegawa, Y.; Nakano, S.; Ibuka, K.

    1986-01-01

    For assessment of the value of delayed hepatobiliary imaging with technetium 99m (/sup 99m/Tc)-(Sn)-N-pyridoxyl-5-methyltryptophan (/sup 99m/Tc-PMT) for specific diagnosis of hepatocellular carcinoma, 88 patients with various malignant and benign liver diseases (49 with hepatocellular carcinoma, 4 with cholangiocellular carcinoma, 10 with metastatic liver carcinoma, 2 with liver cysts, 2 with liver hemangioma, 1 with liver abscess, 2 with intrahepatic lithiasis, 12 with liver cirrhosis, and 6 with chronic hepatitis) were studied. In 20 (41%) of the 49 patients with hepatocellular carcinoma, greater uptake of /sup 99m/Tc-PMT by the tumor than by the surrounding liver tissue was seen in delayed hepatobiliary images, whereas in eight patients (16%), equilibrated uptake was seen. No increased uptake of the radioisotope by hepatic lesions was seen in 21 patients with localized liver diseases other than hepatoma. Moreover, in 18 patients with diffuse liver diseases, no focal accumulation of the radioisotope was seen in delayed /sup 99m/Tc-PMT images. In addition, of 28 patients with hepatocellular carcinoma in whom the serum alpha-fetoprotein level showed little or no increase, 12 showed increased uptake of /sup 99m/Tc-PMT by the tumor. In assessing delayed /sup 99m/Tc-PMT images, however, it was necessary to consider following complications: accumulation of tracer in obstructed and dilated biliary trees; retention of radioactivity in nonneoplastic liver tissues; difficulties in evaluating /sup 99m/Tc-PMT uptake by small hepatic tumors; overlapping of radioactivity in the gut and gallbladder in delayed /sup 99m/Tc-PMT images of tumors. This study indicates that delayed /sup 99m/Tc-PMT images can be useful in the diagnosis of hepatocellular carcinoma

  7. Combined common bile duct and gastric outlet obstruction demonstrated during hepatobiliary scintigraphy

    Energy Technology Data Exchange (ETDEWEB)

    Moreno, A.J.; Rodriguez, A.A.; Sorensen, K.A.; Turnbull, G.L.; Parker, A.L.

    1985-06-01

    A 64-year-old man presented with jaundice. Hepatobiliary imaging using /sup 99m/Tc-DISIDA revealed complete hepatobiliary tract obstruction with a photopenic area corresponding to a dilated gallbladder and a large photopenic region corresponding to a distended stomach as a result of gastric outlet obstruction. At surgery, carcinoma of the head of the pancreas was found to be the cause of the combined common bile duct and gastric outlet obstruction.

  8. Combined common bile duct and gastric outlet obstruction demonstrated during hepatobiliary scintigraphy

    International Nuclear Information System (INIS)

    Moreno, A.J.; Rodriguez, A.A.; Sorensen, K.A.; Turnbull, G.L.; Parker, A.L.

    1985-01-01

    A 64-year-old man presented with jaundice. Hepatobiliary imaging using sup(99m)Tc-DISIDA revealed complete hepatobiliary tract obstruction with a photopenic area corresponding to a dilated gallbladder and a large photopenic region corresponding to a distended stomach as a result of gastric outlet obstruction. At surgery, carcinoma of the head of the pancreas was found to be the cause of the combined common bile duct and gastric outlet obstruction. (orig.)

  9. Specific preoperative diagnosis of choledochal cysts by combined sonography and hepatobiliary scintigraphy

    International Nuclear Information System (INIS)

    Papanicolaou, N.; Abramson, S.J.; Teele, R.L.; Treves, S.

    1985-01-01

    The combined use of sonography and hepatobiliary scintigraphy correctly identified a choledochal cyst preoperatively in seven consecutive infants and children. The high resolution anatomic images provided by sonography coupled with physiologic data on filing of the cyst, biliary patency and liver function derived from radionuclide scanning offer valuable information in the diagnosis and planning of corrective surgery of the cyst and coexisting hepatobiliary anomalies. Invasive diagnostic procedures should be reserved for occasional problematic cases [fr

  10. Diagnostic value of hepatobiliary sequence scintigraphy in patients with postcholecystectomy syndrome

    International Nuclear Information System (INIS)

    Frey, H.; Jorke, D.; Gottschild, D.; Langbein, T.; Zinner, G.; Kob, D.

    1992-01-01

    The autors report about the possibility of registration from functionally disturbances of gall fluid with the help of hepatobiliary sequence-scintigraphy in patients with postcholecystectomy-syndrome. The diagnostic importance of this methode and the meaning of other usually procedures is discussed. A selection of patients succeed in objective manner with hepatobiliary sequence-scintigraphy together with clinically dates of laboratory. In patients with postcholecystectomy-syndrome the procedure can show functionally disturbances in the area of extrahepatic gall ways. (orig.) [de

  11. Surgical outcomes for 131 cases of carcinosarcoma of the hepatobiliary tract.

    Science.gov (United States)

    Okabayashi, Takehiro; Shima, Yasuo; Iwata, Jun; Iiyama, Tatsuo; Sumiyoshi, Tatsuaki; Kozuki, Akihito; Tokumaru, Teppei; Hata, Yasuhiro; Noda, Yoshihiro; Morita, Masanori

    2014-06-01

    Carcinosarcoma of the hepatobiliary tract is highly aggressive and has a poor prognosis even after curative resection. The purpose of this study was to collate and analyze published data to clarify the surgical outcome of carcinosarcoma of the hepatobiliary tract and the relationships between potential prognostic factors and survival after surgery. We surveyed worldwide literature from 1970 to 2012 and obtained clinicopathological data for 131 patients who had undergone surgical resection for carcinosarcoma of the hepatobiliary tract, including one patient from our clinic. The relationships between potential prognostic factors and survival rates were examined using the Kaplan-Meier method and the log-rank test. The overall 1-, 3-, and 5-year survival rates for patients with carcinosarcoma of the hepatobiliary tract after surgery were 44.0, 29.3, and 27.0 %, respectively. In univariate analyses, age and gender were not significant prognostic factors; however, advanced stage according to the classification of the Union for International Cancer Control in resected specimens was significantly associated with a shorter survival time after surgery. Although carcinosarcoma of the hepatobiliary tract remains a rare disease worldwide, its poor prognosis, even after curative resection, demands further epidemiological and pathological study that could lead to the development of new management strategies.

  12. Hepato-biliary effects of mucoviscidosis: use of Mebrofenine scintigraphy

    International Nuclear Information System (INIS)

    Perrin-Fayolle, O.; Morelec, I.; Gilly, R.; Roche, S.; Sappey-Marinier, D.; Briere, J.; Bonmartin, A.; Bellon, G.

    1997-01-01

    The objective of this work is the scintigraphic profile of patients afflicted with mucoviscidosis with portal hypertension (PHT) and the questions whether there exists a criterion to characterized the first stage of fibrosis as well as whether exist in this stage lesions of hepato cellular insufficiency (HCI). The method of the work implied the study of the dynamics of 60 minutes after injecting 40 - 120 MBq of Mebrofenine in 18 patients, 9 presenting a certain PHT, and 9, signs of hepatobiliary affliction without genuine PHT. In the population with PHT, all patients presented a splenomegaly, a very heterogeneous fixation and a retention of the tracer in the intrahepatic-biliary tracts (IHBT) with augmentation of T 1/2 in 5 cases; 8 presented a diminution of the hepatic extraction fraction (HEF), serving as control of HCI. In the population without PHT 2 patients are normal. In the other seven, the most frequently found anomalies are the accumulation of tracer in the IHBT (5/7) and the hepatic heterogeneity (4/7). HEF is low in one case. No dilatation was visible by echography. In conclusion, the accumulation in the IHBT (14 patients, 9 PHT and 5 non PHT) expresses the presence of a functional stasis without organic effects (no echographic dilatation), consequence of a obstruction of biliary ducts by mucus plugs due to dehydration of the bile. The HEF, labeller of HCI, is low in 8 PHT and in one non-PHT, hence tardy in the evolution of the disease, the portal cirrhosis occurring at more on less long term. This parameter can not be considered as a labeller of fibrosis, on the contrary, the accumulation of this tracer in the IHBT and the hepatic heterogeneity seems more interesting for an early detection and start of a preventive treatment

  13. Detection of common bile duct stone by hepatobiliary scintigraphy

    International Nuclear Information System (INIS)

    Itoh, Hisao; Sakai, Toyohiko; Takahashi, Norio

    1991-01-01

    Hepatobiliary scintigraphy and direct X-ray cholangiography were compared in 29 patients with common bile duct (CBD) stones confirmed at surgery. The scintigraphic findings included no visualization of the biliary system (NV), pooling of bile in the biliary system (PB), prolonged transit time over 60 min (PTT), filling defect in the CBD image (FD), and reflux of bile toward the intrahepatic ducts after gallbladder stimulation (RB). The positive rates of NV, PB, PTT, FD, and RB in patients with CBD stones were 7%, 31%, 17%, 48%, and 14%, respectively. One or more of these five findings was found in 83%. Although the NV was a useful finding suggesting complete obstruction of the CBD, it shared little in the diagnosis of CBD stone. The positive rate of the PB was relatively high and it would be a useful finding as an indication of the presence of passage disturbance of the CBD. The PB was usually accompanied by the FD. The PTT had some usefulness in the detection of incomplete obstruction of the CBD in patients with a visualized gallbladder. In patients with no visualization of the gallbladder, however, the transit time tended to be shorter than that of gallbladder visualized patients. Therefore, the judgement of PTT in patients with no visualized gallbladder needed another criteria. The FD was the most frequent among the five findings and the sites of FD correlated well with CBD stones on direct X-ray cholangiography. The FD would be a reliable finding indicating CBD stone or CBD stenosis. Although the RB was a finding limited in patients with a visualized gallbladder, it seemed to be a helpful findings for the detection of CBD stone in patients with a mildly dilated CBD. (author)

  14. [The biochemical markers of hepatobiliary function in children under environmental pollution].

    Science.gov (United States)

    Lukach, M V; Hnateĭko, O Z; Kosmynina, N S

    2014-01-01

    It has been carred out an analysis of biochemical parameters of the hepatobiliary system in 119 children who have been living in ecologically unfavourable districts in order to improve early diagnosis of environmentally triggered hepatobiliary disease. Our results found that 57.2% of patients from polluted region had early signs of liver dysfunction the most frequently of which was elevation of biochemical markers of cholestasis. Among the investigated enzymes the high frequency of abnormal levels of gamma-glutamyltransferase (54.6%) alkaline phosphatase (36.1%), sorbitol dehydrogenase (28.6%) were detected in children from ecologically unfavorable districts which may indicate that these markers were helpful for the early diagnosis of environmentally triggered hepatobiliary disease. It was revealed that almost every third child (41.1% examined children) from the ecologically unfavourable districts had decrease of liver detoxification enzyme activity (arginase).

  15. Multimodality imaging of hepato-biliary disorders in pregnancy: a pictorial essay.

    Science.gov (United States)

    Ong, Eugene M W; Drukteinis, Jennifer S; Peters, Hope E; Mortelé, Koenraad J

    2009-09-01

    Hepato-biliary disorders are rare complications of pregnancy, but they may be severe, with high fetal and maternal morbidity and mortality. Imaging is, therefore, essential in the rapid diagnosis of some of these conditions so that appropriate, life-saving treatment can be administered. This pictorial essay illustrates the multimodality imaging features of pregnancy-induced hepato-biliary disorders, such as acute fatty liver of pregnancy, preeclamsia and eclampsia, and HELLP syndrome, as well as those conditions which occur in pregnancy but are not unique to it, such as viral hepatitis, Budd-Chiari syndrome, focal hepatic lesions, biliary sludge, cholecystolithiasis, and choledocholithiasis.

  16. Hepatobiliary functional scintiscanning (HBFS) - a nuclear medical method for diagnosis of icteric diseases

    International Nuclear Information System (INIS)

    Weber, K.

    1979-01-01

    The results of 146 hepatobiliary functional scintiscannings were analysed and compared with those results obtained by means of laboratory and roentgenologic methods. In 115 cases the obtained results could be examined by the final diagnosis. The accuracy of the HBFS was 87%. In hepatobiliary functional scintiscanning the indications are the differential diagnoses between hepatic and post-hepatic icterus and between total and subtotal obstruction. This method can be applied for all patients whose bilirubin concentration of the blood does not exceed 15 mg%. It can be performed even with serious syndromes or heavy contrast media allergies, because any side effects are absent. (orig.) [de

  17. Structure-activity studies on 99mTc phenolic aminocarboxyllic acid hepatobiliary agente

    International Nuclear Information System (INIS)

    Maddalena, D.J.; Wilson, J.G.; Snowdon, G.M.

    1987-01-01

    Biodistributions of a series of eight 99m Tc hydroxybenzylsarcosine (HBS) complexes were carried out in rats and their urinary and hepatobiliary excretion compared with their lipophilicities, the influence of substituent on the phenyl ring and plasma protein binding ability. The charge on the complexes was determined by electrophoresis at varying pH values. The HBS derivatives formed anionic complexes with 99m Tc that excreted mainly via the urinary route. An increase in the lipophilicity of the complexes by substitution of halogens onto the phenyl ring led to an increase in serum protein binding and a decrease in the urinary output but hat no direct effect on hepatobiliary output. (Author) [es

  18. A study on hepato-biliary and alimentary scintigram by means of triple tracer method

    International Nuclear Information System (INIS)

    Aibata, Hirofumi; Torizumi, Kazutami; Okada, Takashi; Kiji, Shigeyuki; Yamada, Ryusaku; Shimada, Kosuke; Taniguchi, Katsutoshi; Aoki, Yozo

    1987-01-01

    In order to evaluate the gastric emptying and postprandial mixing of bile with food, the scintigraphies of hepatobiliary and gastrointestinal tracts by using three different kinds of radioisotopes were performed simultaneously ( 99m Tc-E · HIDA for hepatobiliary scintigraphy, 111 In-DTPA containing orange juice and 131 I-albumin containing scrambled egg for gastrointestinal scintigraphy). This method was available for observation of gastric emptying of liquid and solid foods and also examination of the mixing effect of bile and food quantitatively. (author)

  19. Data on hepatobiliary examination by sup(99m)Tc dimethyl IDA

    International Nuclear Information System (INIS)

    Herry, J.Y.; Messner, M.; Le Jeune, J.J.; Moisan, A.

    1980-01-01

    Hepatobiliary elimination of sup(99m)Tc dimethyl IDA was studied by scintiphotographic detection in 16 normal subjects. Normal criterion were established. Scintiphotographic modifications due to the principal hepatobiliary disease were described. Abnormal scintiphotographic sequences can be described in terms of accumulative figures in the biliary tract, of deficit of hepatocytary collecting, of figures of hepatocytary retention of deficit of local fixation, of absence of gallbladder illumination. Examination by sup(99m)Tc dimethyl IDA is a precious help for diagnosis of icterus, of disease of the gallbladder. An interesting indication is control of biliarydigestive anastomosis [fr

  20. Experimental colitis in rats induces low-grade endotoxinemia without hepatobiliary abnormalities

    NARCIS (Netherlands)

    Brand, H. S.; Maas, M. A.; Bosma, A.; van Ketel, R. J.; Speelman, P.; Chamuleau, R. A.

    1994-01-01

    In three experimental models in rats, surgical construction of a self-filling blind loop (SFBL), trinitrobenzene sulfonic acid (TNB) -induced colitis, and the combination of SFBL and TNB, the hypothesis was studied that intestine-derived endotoxins play a role in the pathogenesis of hepatobiliary

  1. Subtle to severe hepatobiliary morbidity in Opisthorchis viverrini endemic settings in southern Laos.

    Science.gov (United States)

    Ayé Soukhathammavong, Phonepasong; Rajpho, Virasack; Phongluxa, Khampheng; Vonghachack, Youthanavanh; Hattendorf, Jan; Hongvanthong, Bouasy; Rasaphon, Oroth; Sripa, Banchob; Akkhavong, Kongsap; Hatz, Christoph; Odermatt, Peter

    2015-01-01

    Evidence of severe hepatobiliary morbidity associated with Opisthorchis viverrini liver fluke infection including cholangiocarcinoma (CCA) is scarce in Laos although O. viverrini infection is highly prevalent. We assessed hepatobiliary morbidity using abdominal ultrasonography (US) in O. viverrini adult patients in Saravan province, Southern Laos. A random sample of 431 O. viverrini patients from 10 villages underwent abdominal US. Mild, moderate and markedly advanced periductal fibrosis was diagnosed in 7.0%, 66.5%, and 17.0% of patients, respectively. Normal liver parenchyma was seen in only 9.5% of patients. Presence of gall stones (13.2%), sludge (1.4%), gall wall thickening (1.2%), bile duct dilatation (1.6%), fatty liver (12.0%), kidney stones (8.6%) and cysts (7.9%) were diagnosed in considerable frequencies. In five patients (1.2%) hepatobiliary lesions suggesting CCA were diagnosed. Tumour markers, i.e. Interleukin-6, plasminogen activator inhibitor and carbohydrate antigen 19-9 were within normal range. The number of CCA suspected liver masses and hepatobiliary morbidity diagnosed among clinically asymptomatic adult patients in O. viverrini endemic area presents a major public health concern in Laos. However, definitive diagnosis of Opisthorchis-related severe sequelae including CCA is urgently needed to gauge the burden of this deadly disease in Laos. Copyright © 2014 Elsevier B.V. All rights reserved.

  2. Robotics in hepatobiliary surgery-initial experience, first reported case series from India

    Directory of Open Access Journals (Sweden)

    S. Goja

    2017-01-01

    Conclusion: This initial series adds to existing data on the feasibility of robotic hepatobiliary cases with inherent advantages of minimal invasive surgery, however with limitation of availability and use of devices like cavitron ultrasonic surgical aspirator (CUSA and higher operative cost.

  3. Anatomy of the Murine Hepatobiliary System: A Whole-Organ-Level Analysis Using a Transparency Method.

    Science.gov (United States)

    Higashiyama, Hiroki; Sumitomo, Hiroyuki; Ozawa, Aisa; Igarashi, Hitomi; Tsunekawa, Naoki; Kurohmaru, Masamichi; Kanai, Yoshiakira

    2016-02-01

    The biliary tract is a well-branched ductal structure that exhibits great variation in morphology among vertebrates. Its function is maintained by complex constructions of blood vessels, nerves, and smooth muscles, the so-called hepatobiliary system. Although the mouse (Mus musculus) has been used as a model organism for humans, the morphology of its hepatobiliary system has not been well documented at the topographical level, mostly because of its small size and complexity. To reconcile this, we conducted whole-mount anatomical descriptions of the murine extrahepatic biliary tracts with related blood vessels, nerves, and smooth muscles using a recently developed transparentizing method, CUBIC. Several major differences from humans were found in mice: (1) among the biliary arteries, the arteria gastrica sinistra accessoria was commonly found, which rarely appears in humans; (2) the sphincter muscle in the choledochoduodenal junction is unseparated from the duodenal muscle; (3) the pancreatic duct opens to the bile duct without any sphincter muscles because of its distance from the duodenum. This state is identical to a human congenital malformation, an anomalous arrangement of pancreaticobiliary ducts. However, other parts of the murine hepatobiliary system (such as the branching patterns of the biliary tract, blood vessels, and nerves) presented the same patterns as humans and other mammals topologically. Thus, the mouse is useful as an experimental model for studying the human hepatobiliary system. © 2015 Wiley Periodicals, Inc.

  4. Indocyanine green labeled with /sup 123/I for dynamic studies of the hepato-biliary system. [/sup 131/I, /sup 125/I

    Energy Technology Data Exchange (ETDEWEB)

    Lambrecht, R.M.; Ansari, A.N.; Wolf, A.P.; Atkins, H.L.

    1975-01-01

    This report summarizes the results to develop an iodine-123 labeled agent for dynamic studies of the hepato-biliary system. Iodine-123 is an ideal nuclide for radiopharmaceuticals, because of its short half-life (T/sub /sup 1///sub 2// = 13.3 hr); its decay with a high abundance (83%) of 159 keV photons; and the reduced patient radiation exposure (a factor of 100 less than iodine-131). Indocyanine green, a tricarbanocyanine dye, was introduced by Heseltine and co-workers in 1956, has several characteristics which suggested that iodine-123 labeled ICG might be potentially useful for hepatic functional evaluation. The plasma clearance and biliary excretion kinetics of /sup 123/I-ICG (in dogs) will be compared to /sup 131/I-rose bengal and bromosulphalein labeled with iodine-125.

  5. The effect of preoperative biliary drainage on infectious complications after hepatobiliary resection with cholangiojejunostomy.

    Science.gov (United States)

    Sugawara, Gen; Ebata, Tomoki; Yokoyama, Yukihiro; Igami, Tsuyoshi; Takahashi, Yu; Takara, Daisuke; Nagino, Masato

    2013-02-01

    Arguments against biliary drainage before pancreatoduodenectomy have been gaining momentum recently. The benefits of biliary drainage before hepatobiliary resection, ie, combined liver and extrahepatic bile duct resection, however, are still debatable. To review the outcomes of patients who underwent hepatobiliary resection, with special attention to preoperative biliary drainage, to investigate whether biliary drainage increases the risk of postoperative infectious complications. This study involved 587 patients who underwent hepatobiliary resection with cholangiojejunostomy, including 475 patients who underwent preoperative biliary drainage and 112 patients who did not. Before each operation, surveillance bile cultures were performed at least once a week. Postoperatively, the bile and drainage fluid were cultured on days 1, 4, and 7. The hospital records of consecutive patients who underwent hepatobiliary resection were reviewed retrospectively. Of the 475 patients with biliary drainage, 356 (74.9%) had a positive bile culture during the preoperative period. The incidence of postoperative infectious complications, including surgical-site infection and bacteremia, was similar between patients with biliary drainage and those without (28.2% vs 28.6%, P = .939). A positive bile culture during the perioperative period was highly associated with infectious complications and was one of the independent predictive factors related to infectious complications in a multivariate analysis. Preoperative biliary drainage is unlikely to increase the incidence of infectious complications after hepatobiliary resection. Perioperative surveillance bile culture is useful for the perioperative selection of appropriate antibiotics because of the high likelihood that micro-organisms isolated from infected sites are identical to those isolated from bile. Copyright © 2013 Mosby, Inc. All rights reserved.

  6. Natural orifice translumenal endoscopic surgery (NOTES) for innovation in hepatobiliary and pancreatic surgery: preface.

    Science.gov (United States)

    Sugimoto, Maki

    2009-01-01

    Natural orifice translumenal endoscopic surgery (NOTES) has captured the interest of interventional endoscopists and may represent the next stage of evolution of minimally invasive surgery. It provides the potential for performance of incisionless operations. It is gaining momentum both in the animal laboratory and in human case reports. Developments in the field of NOTES have led to the formation of the Natural Orifice Surgery Consortium for Assessment and Research (NOSCAR) in 2006. In this special issue, the current trends in NOTES in the field of hepatobiliary and pancreatic surgery are featured, including NOTES cholecystectomy, hepatectomy splenectomy, pancreatic necrosectomy, and the future of NOTES. In this issue, we discuss the potential benefits of these procedures in hepatobiliary and pancreatic surgery. We have just started the evaluation process for this new technology. The concept of NOTES is becoming established and is enormously advantageous for the patient. Both the surgeon and gastroenterologist should contribute to developing NOTES in making use of their specialties.

  7. Diagnostic imaging of digestive tract involvement in cystic fibrosis. Part 1: hepatobiliary disease

    International Nuclear Information System (INIS)

    Miralles, M.; Gonzalez, G.; Serrano, C.; Manzanares, J.; Berrocal, T.

    1998-01-01

    Cystic fibrosis is a severe hereditary disease characterized by epithelial chloride channel dysfunction, leading to the production of abnormally thick secretions. The abnormal gene is located on the long arm of chromosome 7. Hepatobiliary involvement derives from ductal obstruction causing cholestasis, steatosis, cirrhosis and portal hypertension. Biliary sludge, cholelithiasis and gallbladder sclerosis and atrophy are common findings. As the correlation between the hepatobiliary changes and their clinical and analytical impact is very limited, imaging techniques are essential in this disease. Ultrasound is the basic imaging tool, both for initial evaluation and follow-up of the hepatic and biliary involvement, although other techniques such as radionuclide imaging, magnetic resonance and computed tomography can be highly useful. Given the long-term, chronic nature of this disease, the use of aggressive techniques or irradiation should be carefully weighed. (Author) 38 refs

  8. Effect of altered thyroid status on the transport of hepatobiliary radiopharmaceuticals

    Energy Technology Data Exchange (ETDEWEB)

    Pahuja, D.N.; Noronha, O.P.

    1985-10-01

    The effect of induced hypothyroidism (by feeding an antithyroid drug-propylthiouracil) on the transport and clearance of the routinely used hepatobiliary radiopharmaceuticals--radioiodinated iodine- T (131I) rose bengal and technetium-99m-N-(4-n-butylphenylcarbamoylmethyl) iminodiacetate, was studied in the rats. Hypothyroidism was associated with depressed growth and retarded clearance of these radiotracers from the in vivo system. Treatment of the hypothyroid rats with thyroxine (2-5 micrograms/100 g b.w. day) for 6 wk, restored these parameters towards normal values. These data suggest that delayed clearance of these hepatobiliary tracers could be related to reduced metabolic rate accompanied with the hypotonia and hypomotility of intestine normally observed in the hypothyroid state.

  9. Postoperative follow-up studies in congenital dilatation of the common bile duct using hepatobiliary scintigraphy

    International Nuclear Information System (INIS)

    Hirobe, Seiichi; Ishida, Haruo; Hayashi, Akira; Kamagata, Shoichiro; Fuchimoto, Yasufumi; Mizuno, Dai; Yano, Tsunehiro; Ishii, Katsumi.

    1995-01-01

    Follow-up studies in congenital dilatation of the common bile duct were done in 20 cases ranging 3 to 20 years after operation. Operative cholangiography had shown dilatation of the intrahepatic bile ducts in 15 patients (75%), of these, 7 patients had cystic dilatation. Five cases of these 7 patients showed prolonged stasis of the nuclide in the cystic dilated intrahepatic bile ducts by 99m Tc-PMT hepatobiliary scintigraphy in the follow-up studies even at 10 years after operation. But none of 20 cases had complication such as intrahepatic lithiasis, cholangitis, and liver dysfunction. Hepatobiliary scintigraphy could provide moderate anatomic and excellent functional information which were useful for these follow-up studies and careful follow-up should be done in the case of cystic dilatation of the intrahepatic bile ducts. (author)

  10. Hepatobiliary scanning with 99mTc-PIPIDA in acute cholecystitis

    Energy Technology Data Exchange (ETDEWEB)

    Mauro, M.A.; McCartney, W.H.; Melmed, J.R.

    1982-01-01

    Ninety-five patients with clinically suspected acute cholecystitis underwent hepatobiliary scanning with 99mTc-PIPIDA. A positive scan (nonvisualization of the gallbladder with visualization of the common bile duct and gut) was found in 29 patients; 25 of them (86%) had surgically proven acute cholecystitis and 4 (14%) had chronic cholecystitis. Five of the 25 with acute cholecystitis had acalculous disease. A negative examination (gallbladder visualization) occurred in 63 patients; 18 (29%) had chronic cholecystitis and 45 (71%) were subsequently found to have nonbiliary disease. Three indeterminate studies (nonvisualization of both the gallbladder and gut) were obtained in patients with choledocholithiasis and chronic cholecystitis. In the evaluation of acute cholecystitis, the 99mTc-PIPIDA hepatobiliary scan was 100% sensitive and 94% specific.

  11. Hepatobiliary scanning with /sup 99//sup m/Tc-PIPIDA in acute cholecystitis

    Energy Technology Data Exchange (ETDEWEB)

    Mauro, M.A.; McCartney, W.H.; Melmed, J.R.

    1982-01-01

    Ninety-five patients with clinically suspected acute cholecystitis underwent hepatobiliary scanning with /sup 99//sup m/Tc-PIPIDA. A positive scan (nonvisualization of the gallbladder with visualization of the common bile duct and gut) was found in 29 patients; 25 of them (86%) had surgically proven acute cholecystitis and 4(14%) had chronic cholecystitis. Five of the 25 with acute cholecystitis had acalculous disease. A negative examination (gallbladder visualization) occurred in 63 patients; 18 (29%) had chronic cholecystitis and 45 (71%) were subsequently found to have nonbiliary disease. Three indeterminate studies (nonvisualization of both the gallbladder and gut) were obtained in patients with choledocholithiasis and chronic cholecystitis. In the evaluation of acute cholecystitis, the /sup 99//sup m/Tc-PIPIDA hepatobiliary scan was 100% sensitive and 94% specific.

  12. Postoperative follow-up studies in congenital dilatation of the common bile duct using hepatobiliary scintigraphy

    Energy Technology Data Exchange (ETDEWEB)

    Hirobe, Seiichi; Ishida, Haruo; Hayashi, Akira; Kamagata, Shoichiro; Fuchimoto, Yasufumi; Mizuno, Dai; Yano, Tsunehiro [Tokyo Metropolitan Kiyose Children`s Hospital (Japan); Ishii, Katsumi

    1995-03-01

    Follow-up studies in congenital dilatation of the common bile duct were done in 20 cases ranging 3 to 20 years after operation. Operative cholangiography had shown dilatation of the intrahepatic bile ducts in 15 patients (75%), of these, 7 patients had cystic dilatation. Five cases of these 7 patients showed prolonged stasis of the nuclide in the cystic dilated intrahepatic bile ducts by {sup 99m}Tc-PMT hepatobiliary scintigraphy in the follow-up studies even at 10 years after operation. But none of 20 cases had complication such as intrahepatic lithiasis, cholangitis, and liver dysfunction. Hepatobiliary scintigraphy could provide moderate anatomic and excellent functional information which were useful for these follow-up studies and careful follow-up should be done in the case of cystic dilatation of the intrahepatic bile ducts. (author).

  13. The MR imaging diagnosis of liver diseases using gadoxetic acid: Emphasis on hepatobiliary phase

    Directory of Open Access Journals (Sweden)

    Woo Kyoung Jeong

    2013-12-01

    Full Text Available Hepatocyte specific contrast agents including gadoxetic acid and gadobenate dimeglumine are very useful to diagnose various benign and malignant focal hepatic lesions and even helpful to estimate hepatic functional reservoir. The far delayed phase image referred to as the hepatobiliary phase makes the sensitivity of detection for malignant focal hepatic lesions increased, but specificity of malignant diseases, including hepatocellular carcinoma, metastasis and cholangiocarcinoma, characterization remained to be undetermined.

  14. Pharmacokinetics and clinical application of technetium 99m-labeled hepatobiliary agents.

    Science.gov (United States)

    Krishnamurthy, G T; Turner, F E

    1990-04-01

    Hepatobiliary imaging, introduced first in late 1950s with iodine 131 rose bengal, has undergone major changes since the introduction of technetium 99m-labeled agents in the late 1970s. 99mTc-labeled iminodiacetic acid (IDA) agents, with their high hepatic uptake and fast biliary excretion, provide superior image resolution in addition to supplying simultaneous physiologic parameters quantitatively. The measurement of hepatic extraction fraction by deconvolutional analysis aids in separating hepatocyte from biliary disease. Excretion half-time calculation by nonlinear least square fit provides a quantitative method of analyzing hepatobiliary function and correlates directly with the severity of disease. The measurement of gallbladder ejection fraction, ejection rate, and common bile duct bile reflux index following cholecystokinin, enables quantification of the degree of obstruction to bile flow through the common bile duct. The combined application of morphologic and physiologic parameters enables diagnosis of various hepatobiliary disease, especially in early stages. Quantitative functional parameters not only provide criteria for diagnosis, but also assist in monitoring the therapeutic benefit from drugs and interventional techniques such as endoscopic sphincterotomy or balloon dilation of the obstruction. Biliary dynamic studies with cholecystokinin assist in distinguishing common bile duct dilation without obstruction from dilation with obstruction. Methods of application of 99mTc-IDA agents in quantitative physiologic studies are reviewed and future direction of their use is proposed.

  15. Clinical analysis of 22 patients with hepatobiliary disease caused by liver fluke

    Directory of Open Access Journals (Sweden)

    ZHANG Hui

    2013-07-01

    Full Text Available ObjectiveTo clinically analyze the hepatobiliary disease caused by the liver fluke and to increase the knowledge of this disease and reduce misdiagnosis. MethodsA retrospective analysis was performed on the clinical data of 22 patients who had a confirmed diagnosis of clonorchiasis after being admitted to our hospital due to hepatobiliary disease over the past 20 years. ResultsOf the 22 patients, who had a mean age of 45.41 years, 19 were males, and 3 were females. When admitted to the hospital, 8 cases were diagnosed with cholecystitis or gallstones, 7 cases with clonorchiasis, and 7 cases with other diseases. Alanine aminotransferase elevation was found in 14 cases (6363%, aspartate aminotransferase elevation in 16 cases (72.72%, total bilirubin elevation in 11 cases (5000%, gamma-glutamyl transpeptidase elevation in 17 cases (77.27%, and increased eosinophils in 14 cases (63.63%. Ten cases (45.45% were diagnosed by fecal examination, 7 cases (31.82% by bile smears, 2 cases (9.09% by liver fluke antibody detection, and 3 cases (1364% according to the history of clonorchiasis. Deworming and comprehensive treatment produced a good outcome in these patients. ConclusionClonorchiasis is endemic and clinically rare, without specific clinical features, and it is easily confused with other hepatobiliary diseases, resulting in a high rate of misdiagnosis. Therefore, for the patients with abdominal pain, jaundice, and liver damage of unknown causes, we should inquire whether they or their family have a special dietary history and need to perform relevant examinations to confirm the diagnosis, so as to provide timely treatment.

  16. Hepatobiliary transporter expression and post-operative jaundice in patients undergoing partial hepatectomy.

    Science.gov (United States)

    Bernhardt, Gerwin A; Zollner, Gernot; Cerwenka, Herwig; Kornprat, Peter; Fickert, Peter; Bacher, Heinz; Werkgartner, Georg; Müller, Gabriele; Zatloukal, Kurt; Mischinger, Hans-Jörg; Trauner, Michael

    2012-01-01

    Post-operative hyperbilirubinaemia in patients undergoing liver resections is associated with high morbidity and mortality. Apart from different known factors responsible for the development of post-operative jaundice, little is known about the role of hepatobiliary transport systems in the pathogenesis of post-operative jaundice in humans after liver resection. Two liver tissue samples were taken from 14 patients undergoing liver resection before and after Pringle manoeuvre. Patients were retrospectively divided into two groups according to post-operative bilirubin serum levels. The two groups were analysed comparing the results of hepatobiliary transporter [Na-taurocholate cotransporter (NTCP); multidrug resistance gene/phospholipid export pump(MDR3); bile salt export pump (BSEP); canalicular bile salt export pump (MRP2)], heat shock protein 70 (HSP70) expression as well as the results of routinely taken post-operative liver chemistry tests. Patients with low post-operative bilirubin had lower levels of NTCP, MDR3 and BSEP mRNA compared to those with high bilirubin after Pringle manoeuvre. HSP70 levels were significantly higher after ischaemia-reperfusion (IR) injury in both groups resulting in 4.5-fold median increase. Baseline median mRNA expression of all four transporters prior to Pringle manoeuvre tended to be lower in the low bilirubin group whereas expression of HSP70 was higher in the low bilirubin group compared to the high bilirubin group. Higher mRNA levels of HSP70 in the low bilirubin group could indicate a possible protective effect of high HSP70 levels against IR injury. Although the exact role of hepatobiliary transport systems in the development of post-operative hyper bilirubinemia is not yet completely understood, this study provides new insights into the molecular aspects of post-operative jaundice after liver surgery. © 2011 John Wiley & Sons A/S.

  17. Hepatobiliary scintigraphy in diagnosis and follow-up of biliary atresia; Stellenwert der hepatobiliaeren Funktionsszintigrafie in Diagnostik und Nachsorge der Gallengangsatresie

    Energy Technology Data Exchange (ETDEWEB)

    Rossmueller, B.; Knesewitsch, P.; Hahn, K. [Klinik und Poliklinik fuer Nuklearmedizin, Klinikum der Ludwig-Maximilians-Univ. Muenchen (Germany)

    2009-03-15

    In newborns with biliary atresia immediate diagnosis is crucial, as only early portoenterostomie (Kasai) may prevent development of an incurable liver cirrhosis. Hepatobiliary scintigraphy has a major role in diagnostic work up, in prognostic evaluation and in postoperativ follow up of biliary atresia. Indication, technical procedure and interpretation of hepatobiliary scintigraphy in children with suspicion of biliary atresia will be discussed. (orig.)

  18. Iron-EHPG as an hepatobiliary MR contrast agent: initial imaging and biodistribution studies

    International Nuclear Information System (INIS)

    Lauffer, R.B.; Greif, W.L.; Stark, D.D.; Vincent, A.C.; Saini, S.; Wedeen, V.J.; Brady, T.J.

    1988-01-01

    A paramagnetic relaxation agent targeted to functioning hepatocytes of the liver and excreted into the bile would be useful in the enhancement of normal liver and biliary anatomy in MR imaging. We sought to demonstrate the feasibility of this approach using the prototype hepatobiliary MR contrast agent, iron(III) ethylenebis-(2-hydroxyphenylglycine) (Fe(EHPG) - ). The biodistribution, relaxation enhancement, and imaging characteristics of Fe(EHPG) - were compared to those of the non-specific iron chelate iron(III) diethylenetriaminepentaacetic acid (Fe(DTPA) 2- ), which has a comparable effect on water proton relaxation times. (author)

  19. Scintigraphic hepatobiliary function studies in newborn infants to diagnose biliary hypoplasia or atresia

    International Nuclear Information System (INIS)

    Askari-Sabi, Z.

    1987-01-01

    The results obtained from scintigraphic hepatobiliary function studies, intraoperative cholangiography and histological examinations in a total of 17 infants suspected of having biliary atresia were compared and analysed with reference to the clinical signs and symptoms observed. In most cases, the individual diagnostic procedures led to consistent findings, even though there were some variations in the clinical picture. Patient outcome is largely determined by the site of atresia, due to which fact surgical correction should be carried out as soon as possible, in any case before the 8th week post partum. (TRV) [de

  20. Focal nodular hyperplasia. /sup 99m/Tc-EHIDA hepatobiliary scintigraphy

    Energy Technology Data Exchange (ETDEWEB)

    Fujimori, Kenji; Saito, Hiroya; Itoh, Kazuo; Furudate, Masayori

    1987-09-01

    One case of focal nodular hyperplasia of the liver was reported. Time activity curves of the hepatobiliary scintigraphy were evaluated. The peak time, T1/2 in excretion phase and mean transit time of the FNH were longer than the normal liver and 13.8 min, 41.8 min and 22.7 min, respectively. Proliferation of the bile duct cell and stenosis of the bile duct were not shown pathologically. Dysfunction of the hepatocytes may cause retention of the /sup 99m/Tc-EHIDA in this case.

  1. Differentiation of infantile jaundice with 99mTc-EHIDA hepatobiliary scintigraphy and determination of bilixanthine from duodenal drainage

    International Nuclear Information System (INIS)

    Zhao Ming; Wu Hua; Huang Zhihua

    1996-01-01

    The purpose of this study was to develop an effective diagnostic method for infantile jaundice. 99m Tc-EHIDA hepatobiliary scintigraphy and determination of bilixanthine from duodenal drainage were carried out in 33 infants with persistent jaundice. The final diagnosis was confirmed by surgical operation, pathology or clinical follow-up. For diagnosing biliary atresia, the sensitivity and specificity of scintigraphy were 100% and 72.7% respectively and those of bilixanthine measurement were 100% and 95.5%. Hepatobiliary scintigraphy may be a sensitive, simple, safe and noninvasive method for differentiating infantile jaundice. Duodenal bilixanthine determination may improve the specificity in the case without intestinal radioactivity in scintigram

  2. Interactions between Bacteria and Bile Salts in the Gastrointestinal and Hepatobiliary Tracts

    Science.gov (United States)

    Urdaneta, Verónica; Casadesús, Josep

    2017-01-01

    Bile salts and bacteria have intricate relationships. The composition of the intestinal pool of bile salts is shaped by bacterial metabolism. In turn, bile salts play a role in intestinal homeostasis by controlling the size and the composition of the intestinal microbiota. As a consequence, alteration of the microbiome–bile salt homeostasis can play a role in hepatic and gastrointestinal pathological conditions. Intestinal bacteria use bile salts as environmental signals and in certain cases as nutrients and electron acceptors. However, bile salts are antibacterial compounds that disrupt bacterial membranes, denature proteins, chelate iron and calcium, cause oxidative damage to DNA, and control the expression of eukaryotic genes involved in host defense and immunity. Bacterial species adapted to the mammalian gut are able to endure the antibacterial activities of bile salts by multiple physiological adjustments that include remodeling of the cell envelope and activation of efflux systems and stress responses. Resistance to bile salts permits that certain bile-resistant pathogens can colonize the hepatobiliary tract, and an outstanding example is the chronic infection of the gall bladder by Salmonella enterica. A better understanding of the interactions between bacteria and bile salts may inspire novel therapeutic strategies for gastrointestinal and hepatobiliary diseases that involve microbiome alteration, as well as novel schemes against bacterial infections. PMID:29043249

  3. Hepatobiliary scintigraphy with 99mTc-PIPIDA in the evaluation of neonatal jaundice

    International Nuclear Information System (INIS)

    Majd, M.; Reba, R.C.; Altman, R.P.

    1981-01-01

    Hepatobiliary scintigraphy with technetium 99m-labeled p-isopropylacetanilido iminodiacetic acid (99mTc-PIPIDA) was used to evaluate 22 neonates with mixed jaundice. Ten patients were proved to have biliary atresia; ten others were diagnosed as having neonatal hepatitis. In the remaining two, jaundice was secondary to prolonged hyperalimentation. Initial studies in all ten patients with biliary atresia showed no evidence of excretion of the tracer into the intestinal tract. Following three to seven days of oral administration of phenobarbital, repeat studies were performed in six of the ten patients. None showed evidence of excretion. Initial studies of the 12 patients with intrahepatic cholestasis showed definite excretion in five, questionable evidence of excretion in two, and no demonstrable excretion in five. Studies after phenobarbital therapy in five of the seven patients with questionable or no excretion on the initial studies showed definite excretion in four. Only in one patient who had poor hepatic extraction did the phenobarbital therapy not change the scintigraphic pattern. The authors conclude that hepatobiliary scintigraphy with 99mTc-PIPIDA after three to seven days of phenobarbital therapy is a highly accurate test for differentiating biliary atresia from other causes of neonatal jaundice

  4. Interactions between Bacteria and Bile Salts in the Gastrointestinal and Hepatobiliary Tracts

    Directory of Open Access Journals (Sweden)

    Verónica Urdaneta

    2017-10-01

    Full Text Available Bile salts and bacteria have intricate relationships. The composition of the intestinal pool of bile salts is shaped by bacterial metabolism. In turn, bile salts play a role in intestinal homeostasis by controlling the size and the composition of the intestinal microbiota. As a consequence, alteration of the microbiome–bile salt homeostasis can play a role in hepatic and gastrointestinal pathological conditions. Intestinal bacteria use bile salts as environmental signals and in certain cases as nutrients and electron acceptors. However, bile salts are antibacterial compounds that disrupt bacterial membranes, denature proteins, chelate iron and calcium, cause oxidative damage to DNA, and control the expression of eukaryotic genes involved in host defense and immunity. Bacterial species adapted to the mammalian gut are able to endure the antibacterial activities of bile salts by multiple physiological adjustments that include remodeling of the cell envelope and activation of efflux systems and stress responses. Resistance to bile salts permits that certain bile-resistant pathogens can colonize the hepatobiliary tract, and an outstanding example is the chronic infection of the gall bladder by Salmonella enterica. A better understanding of the interactions between bacteria and bile salts may inspire novel therapeutic strategies for gastrointestinal and hepatobiliary diseases that involve microbiome alteration, as well as novel schemes against bacterial infections.

  5. Hepatobiliary scintigraphy in chronic intrahepatic cholestasis. Diagnosis of primary sclerosing cholangitis

    Energy Technology Data Exchange (ETDEWEB)

    Aburano, Tamio; Takayama, Teruhiko; Shuke, Noriyuki

    1987-05-01

    Primary sclerosing cholangitis (PSC) is a rare disease of unknown origin, leading to chronic intermittent cholestasis. Due to its low incidence, insidious clinical onset and varied clinical picture, the diagnosis is often delayed by years. PSC is sometimes diagnosed falsely as another disease of chronic intermittent cholestasis, primary biliary cirrhosis (PBC). In the present study, the hepatobiliary imaging with Tc-99m diethyl IDA was done in a total of 14 patients with chronic intermittent cholestasis including 3 patients with PSC and 11 patients with PBC, in order to decide its clinical usefulness as a noninvasive method for the differentiation between PSC and PBC. All three patients with PSC showed a typical pattern of radionuclide stasis within the area of intrahepatic and/or extrahepatic ductal system, representing the stenosis on endoscopic retrograde cholangiogram. On the other hand, none of 11 patients with PBC showed any radionuclide stasis within the area of intrahepatic and/or extrahepatic ductal system. This result suggests that the radionuclide hepatobiliary imaging may be a noninvasive method for investigating patients with chronic intermittent cholestasis, leading to earlier differentiation between PSC and PBC.

  6. Prediagnostic selenium status and hepatobiliary cancer risk in the European Prospective Investigation into Cancer and Nutrition cohort

    NARCIS (Netherlands)

    Hughes, David J.; Duarte-Salles, Talita; Hybsier, Sandra; Trichopoulou, Antonia; Stepien, Magdalena; Aleksandrova, Krasimira; Overvad, Kim; Tjønneland, Anne; Olsen, Anja; Affret, Aurélie; Fagherazzi, Guy; Boutron-Ruault, Marie Christine; Katzke, Verena; Kaaks, Rudolf; Boeing, Heiner; Bamia, Christina; Lagiou, Pagona; Peppa, Eleni; Palli, Domenico; Krogh, Vittorio; Panico, Salvatore; Tumino, Rosario; Sacerdote, Carlotta; Bueno de Mesquita, Hendrik Bastiaan|info:eu-repo/dai/nl/06929528X; Peeters, Petra H.|info:eu-repo/dai/nl/074099655; Engeset, Dagrun; Weiderpass, Elisabete; Lasheras, Cristina; Agudo, Antonio; Sánchez, Maria José; Navarro, Carmen; Ardanaz, Eva; Dorronsoro, Miren; Hemmingsson, Oskar; Wareham, Nicholas J.; Khaw, Kay Tee; Bradbury, Kathryn E.; Cross, Amanda J.; Gunter, Marc; Riboli, Elio; Romieu, Isabelle; Schomburg, Lutz; Jenab, Mazda

    2016-01-01

    Selenium status is suboptimal in many Europeans and may be a risk factor for the development of various cancers, including those of the liver and biliary tract. Objective: We wished to examine whether selenium status in advance of cancer onset is associated with hepatobiliary cancers in the EPIC

  7. Function and regulation of ATP-binding cassette transport proteins involved in hepatobiliary transport (vol 12, pg 13, 2000)

    NARCIS (Netherlands)

    Hooiveld, GJEJ; van Montfoort, JE; Meijer, DKF; Muller, M

    Hepatobiliary transport of endogenous and exogenous compounds is mediated by the coordinated action of multiple transport systems present at the sinusoidal (basolateral) and canalicular (apical) membrane domains of hepatocytes. During the last few years many of these transporters have been cloned

  8. Hepatobiliary imaging

    International Nuclear Information System (INIS)

    Klingensmith, W.C.

    1988-01-01

    If the gallbladder is not being evaluated, no patient preparation is necessary. However, if the gallbladder is being evaluated, the patient must have fasted for approximately 2-14 hr prior to injection of the radiopharmaceutical. If the patient has fasted for less than 2 hr. the gallbladder may still be contracting and, thus, prevent the inflow of radioactive bile. On the other hand, if the patient has fasted for more than 14 hr. the gallbladder may have concentrated its contents to the point where the osmotic gradient prevents further reabsorption of water. The author discusses how, in this situation, an analog of cholecystokinin-pancreazymin such as sincalide can be given intravenously approximately 20 min before injection of the radiopharmaceutical. This agent will cause the gallbladder to empty so that reabsorption of water and filling of the gallbladder can begin again

  9. MR imaging evaluation of pancreas and hepatobiliary system in cystic fibrosis

    International Nuclear Information System (INIS)

    Murayama, S.; Robinson, A.E.; Stallworth, J.; Mulvihill, D.; Beckerman, R.; Davis, S.

    1988-01-01

    The pancreas and hepatobiliary system of 20 patients with cystic fibrosis were analyzed with a 1.5-T magnet. T1-weighted, T2-weighted, and proton-density images were obtained, and the T1 and T2 values of the pancreas were calculated. Signal intensity ratios were calculated for the signal intensities of the pancreas and the liver relative to that of muscle and fat on each pulse sequence. Fatty replacement of the pancreas and regenerating nodules of biliary cirrhosis were readily identified on T1-weighted images. The T1 values for pancreatic tissue showed promise as a good marker for pancreatic disease progression. Pancreas-to-fat signal intensity ratios on 300/20 (repetition time msec/echo time msec) and 2,000/75 images were considered to be a good standard for evaluating the level of pancreatic involvement

  10. Radionuclide diagnosis of hepatobiliary system functional state at complex treatment of uterine cancer

    International Nuclear Information System (INIS)

    Vusik, Yi.M.; Slabodchikov, M.Je.; Nesterov, V.G.

    1993-01-01

    The study involved 68 patients with uterine cancer (stage II-III) who underwent complex treatment and 16 healthy women aged 27-69. The patients were performed hepatography (44 of them - dynamic liver scintigraphy with Tc 99m - mezida) before the treatment, immediately after and 1-1.5 and 2-3 years after the course of radiotherapy. Latent disturbance of hepatobiliary system function which can be revealed with radionuclide study is shown to be observed in the patients with uterine cancer before the treatment. The level of hepatocytes functioning after the treatment depends largely on their initial functional state. Computer assisted multichannel radiography with evaluation of effective blood flow in the liver and effective fraction of minute volume of the blood flow is the most reasonable for monitoring hepatocytes function during treatment in the patients with uterine cancer

  11. Sporadic incidence of Fascioliasis detected during Hepatobiliary procedures: A study of 18 patients from Sulaimaniyah governorate

    Directory of Open Access Journals (Sweden)

    Hawramy Tahir Abdullah Hussein

    2012-12-01

    Full Text Available Abstract Background Fascioliasis is an often-neglected zoonotic disease and currently is an emerging infection in Iraq. Fascioliasis has two distinct phases, an acute phase, exhibiting the hepatic migratory stage of the fluke’s life cycle, and a chronic biliary phase manifested with the presence of the parasite in the bile ducts through hepatic tissue. The incidence of Fascioliasis in Sulaimaniyah governorate was unexpected observation. We believe that shedding light on this disease in our locality will increase our physician awareness and experience in early detection, treatment in order to avoid unnecessary surgeries. Findings We retrospectively evaluated this disease in terms of the demographic features, clinical presentations, and managements by reviewing the medical records of 18 patients, who were admitted to the Sulaimani Teaching Hospital and Kurdistan Centre for Gastroenterology and Hepatology. Patients were complained from hepatobiliary and/or upper gastrointestinal symptoms and diagnosed accidentally with Fascioliasis during hepatobiliary surgeries and ERCP by direct visualization of the flukes and stone analysis. Elevated liver enzymes, white blood cells count and eosinophilia were notable laboratory indices. The dilated CBD, gallstones, liver cysts and abscess were found common in radiological images. Fascioliasis diagnosed during conventional surgical CBD exploration and choledochodoudenostomy, open cholecystectomy, surgical drainage of liver abscess, ERCP and during gallstone analysis. Conclusion Fascioliasis is indeed an emerging disease in our locality, but it is often underestimated and ignored. We recommend the differential diagnosis of patients suffering from Rt. Hypochondrial pain, fever and eosinophilia. The watercress ingestion was a common factor in patient’s history.

  12. Identity disorder and social-psychological adaptation in patients with hepatobiliary disease

    Directory of Open Access Journals (Sweden)

    V. V. Khramtsova

    2017-12-01

    Full Text Available Negative bodily experience due to health complications and disability is perceived as a difficult life situation. The success of adaptation, commitment to treatment and cooperation with a doctor depend on the personality characteristics that define behavioral representations. Aim. Investigate the structure of identity and mechanisms of social-psychological adaptation of patients with the hepatobiliary system disease. Contingent and methods. 75 patients with a diffuse liver disease - chronic hepatitis, mostly of viral etiology (36 people and liver cirrhosis (39 patients have been examined. We have applied clinical, clinical-psychological, mathematical and empirical methods, semi-structured cross-interviews ("patient-doctor", "patient-psychologist", diagnostics of personal characteristics, identity structure, social-psychological components of adaptation. Three leading personality profiles have been highlighted. Results. Persons with a disharmonious personality development are characterized by disorders in the area of identity formation and development. Fragmentation, the impossibility of personal integration and severe penetrability from the environment contribute to social-psychological maladjustment. The coping is aimed at preserving the problem situation and intensifying the intrapersonal conflict. For persons with difficulties in the adaptation of the personality, a violation of activity interaction with the surrounding world is characteristic, a ban on one's self-identity. Social adaptation is often disrupted due to instability in the emotional-volitional sphere and choosing low-adaptive coping strategies. Genuine "I" and identity formation is impeded for the individuals suppressing aggressive impulses. Adaptability tends to be discrete. With mental stress increasing, the likelihood of choosing low-adaptive coping strategies increases. Conclusions. When drafting psycho-correction programs and medical treatment of people with a hepatobiliary

  13. Characteristic MR and CT imaging findings of hepatobiliary paragonimiasis and their pathologic correlations

    International Nuclear Information System (INIS)

    Lu, Chunyan; Hu, Yajun; Chen, Weixia

    2012-01-01

    Background: Hepatobiliary paragonimiasis (HP) is not commonly encountered and may be confused with hepatobiliary tumors; however, computed tomography (CT) and magnetic resonance imaging (MRI) features of HP allow this entity to be distinguished from other diseases. Purpose: To present the CT and MRI findings in patients with HP and to describe some specific imaging findings along with their pathological correlations. Material and Methods: Imaging and clinical findings of 21 patients (9 boys/men and 12 girls/women; age range 3-67 years; mean age 40 years) who were diagnosed with HP were retrospectively evaluated. Among these patients, 16 underwent CT examination only, two had MR examination only, and three underwent both CT and MR. All patients underwent surgery, and the HP diagnosis was confirmed by the surgical and histopathologic results. Results: Chronic abdominal pain or back pain was reported by 14 patients, severe abdominal pain with acute onset was reported by one patient, and six patients were asymptomatic and were discovered incidentally. Peripheral eosinophilia was present in 14 patients (14/21, 66.7%), and abnormal liver function tests were found in 16 patients (16/21, 76.2%). Of the 19 patients who underwent CT imaging, 17 patients showed multiple mixed hypodense lesions or multiple cysts with inlaying septation with separate irregular rims or circular enhancement on post-contrast CT images. Tunnel-shaped micro abscesses and necrotic cavities were found in the lesions of 12 of those 17 patients. The other two patients showed smaller cystic masses. MRI showed faveolate T1 hypointense and T2 hyperintense areas in the liver parenchyma with rim or peripheral enhancement. Nodular or circular hyperintense materials were found scattered in the lesions on T1-weighted imaging. Conclusion: CT and MRI can reveal the radiological-pathological features of HP. Together with laboratory findings, MRI and CT findings may provide diagnostic clues, especially in endemic

  14. Risk of hepatobiliary cancer after solid organ transplant in the United States.

    Science.gov (United States)

    Koshiol, Jill; Pawlish, Karen; Goodman, Marc T; McGlynn, Katherine A; Engels, Eric A

    2014-09-01

    Studies of liver cancer risk in recipients of solid organ transplants generally have been small, yielding mixed results, and little is known about biliary tract cancers among transplant recipients. We identified incident hepatobiliary cancers among 201,549 US recipients of solid organs, from 1987 through 2008, by linking data from the US transplant registry with 15 cancer registries. We calculated standardized incidence ratios (SIRs), comparing risk relative to the general population. We also calculated incidence rate ratios (RRs), comparing risk for hepatocellular carcinoma (HCC) and total (intrahepatic and extrahepatic) cholangiocarcinoma among subgroups of recipients. Of transplant recipients, 165 developed hepatobiliary cancers (SIR, 1.2; 95% confidence interval [CI], 1.0-1.4). HCC risk was increased among liver recipients (SIR, 1.5; 95% CI, 1.0-2.2), especially 5 or more years after transplant (SIR, 1.8; 95% CI, 1.0-3.0). Cholangiocarcinoma was increased among liver (SIR, 2.9; 95% CI, 1.6-4.8) and kidney recipients (SIR, 2.1; 95% CI, 1.3-3.1). HCC was associated with hepatitis B virus (RR, 3.2; 95% CI, 1.3-6.9), hepatitis C virus (RR, 10; 95% CI, 5.9-16.9), and non-insulin-dependent diabetes (RR, 2.5; 95% CI, 1.2-4.8). Cholangiocarcinoma was associated with azathioprine maintenance therapy (RR, 2.0; 95% CI, 1.1-3.7). Among liver recipients, primary sclerosing cholangitis was associated with an increased risk of cholangiocarcinoma, compared with the general population (SIR, 21; 95% CI, 8.2-42) and compared with liver recipients without primary sclerosing cholangitis (RR, 12.3; 95% CI, 4.1-36.4). Risks for liver and biliary tract cancer are increased among organ transplant recipients. Risk factors for these cancers include medical conditions and potentially medications taken by recipients. Copyright © 2014 AGA Institute. Published by Elsevier Inc. All rights reserved.

  15. Increased biliary excretion of glutathione is generated by the glutathione-dependent hepatobiliary transport of antimony and bismuth.

    Science.gov (United States)

    Gyurasics, A; Koszorús, L; Varga, F; Gregus, Z

    1992-10-06

    We have recently demonstrated that the hepatobiliary transport of arsenic is glutathione-dependent and is associated with a profound increase in biliary excretion of glutathione (GSH), hepatic GSH depletion and diminished GSH conjugation (Gyurasics A, Varga F and Gregus Z, Biochem Pharmacol 41: 937-944 and Gyurasics A, Varga F and Gregus Z, Biochem Pharmacol 42: 465-468, 1991). The present studies in rats aimed to determine whether antimony and bismuth, other metalloids in group Va of the periodic table, also possess similar properties. Antimony potassium tartrate (25-100 mumol/kg, i.v.) and bismuth ammonium citrate (50-200 mumol/kg, i.v.) increased up to 50- and 4-fold, respectively, the biliary excretion of non-protein thiols (NPSH). This resulted mainly from increased hepatobiliary transport of GSH as suggested by a close parallelism in the biliary excretion of NPSH and GSH after antimony or bismuth administration. Within 2 hr, rats excreted into bile 55 and 3% of the dose of antimony (50 mumol/kg, i.v.) and bismuth (150 mumol/kg, i.v.), respectively. The time courses of the biliary excretion of these metalloids and NPSH or GSH were strikingly similar suggesting co-ordinate hepatobiliary transport of the metalloids and GSH. However, at the peak of their excretion, each molecule of antimony or bismuth resulted in a co-transport of approximately three molecules of GSH. Diethyl maleate, indocyanine green and sulfobromophthalein (BSP), which decreased biliary excretion of GSH, significantly diminished excretion of antimony and bismuth into bile indicating that hepatobiliary transport of these metalloids is GSH-dependent. Administration of antimony, but not bismuth, decreased hepatic GSH level by 30% and reduced the GSH conjugation and biliary excretion of BSP. These studies demonstrate that the hepatobiliary transport of trivalent antimony and bismuth is GSH-dependent similarly to the hepatobiliary transport of trivalent arsenic. Proportionally to their biliary

  16. Cholescintigraphic abnormality in a case of Kawasaki syndrome

    International Nuclear Information System (INIS)

    Zanzi, I.; Cuomo Perpignano, M.; Margouleff, D.; Aiges, H.

    1985-01-01

    A 26-month-old girl with Kawasaki syndrome (mucocutaneous lymph node syndrome) is presented. Liver function studies were abnormal and sonographic examination revealed hydrops of the gallbladder. The Tc-99m DISIDA cholescintigraphy demonstrated both early and delayed nonvisualization of the gallbladder. A photopenic area was noted in and below the gallbladder fossa and there was medial and upward displacement of the common bile duct. It appears that Kawasaki syndrome may result in nonvisualization of the gallbladder by cholescintigraphy. Accordingly, this diagnosis should be added to the list of conditions associated with nonvisualization of the gallbladder by biliary scintigraphy

  17. Preoperative biliary MRSA infection in patients undergoing hepatobiliary resection with cholangiojejunostomy: incidence, antibiotic treatment, and surgical outcome.

    Science.gov (United States)

    Takara, Daisuke; Sugawara, Gen; Ebata, Tomoki; Yokoyama, Yukihiro; Igami, Tsuyoshi; Nagino, Masato

    2011-04-01

    There have been no reports on the impact of preoperative biliary MRSA infection on the outcome of major hepatectomy. The aim of this study was to review the surgical outcome of patients who underwent hepatobiliary resection after biliary drainage and to evaluate the impact of preoperative biliary MRSA infection. Medical records from 350 patients who underwent hepatobiliary resection with cholangiojejunostomy after external biliary drainage were retrospectively reviewed. Of the 350 study patients, 14 (4.0%) had MRSA-positive bile culture, 246 (70.3%) had positive bile culture without MRSA growth, and the remaining 90 (25.7%) had negative bile culture. In all of the patients with MRSA-positive bile culture, vancomycin was prophylactically administered after surgery. Of the 14 patients, 6 (42.9%) had surgical site infections, including wound infection in 5 patients and intra-abdominal abscess in 2 patients. The incidence of surgical site infection in the 14 MRSA-positive patients was higher but not statistically significant compared to the incidence in other patient groups. All 14 patients tolerated difficult hepatobiliary resection. Of the 350 study patients, 28 (8.0%) had postoperative MRSA infections. Multivariate analysis identified preoperative MRSA-positive bile culture as a significant independent risk factor for postoperative MRSA infection. Preoperative biliary MRSA infection is troublesome as it is an independent risk factor of postoperative MRSA infection. Even in such troublesome situations, however, difficult hepatobiliary resection can be performed with acceptable rates of morbidity and mortality using appropriate antibiotic prophylaxis, including vancomycin, based on bile culture.

  18. Added value of Gd-EOB-DTPA-enhanced Hepatobiliary phase MR imaging in evaluation of focal solid hepatic lesions

    International Nuclear Information System (INIS)

    Haimerl, Michael; Wächtler, Max; Platzek, Ivan; Müller-Wille, Rene; Niessen, Christoph; Hoffstetter, Patrick; Schreyer, Andreas Georg; Stroszczynski, Christian; Wiggermann, Philipp

    2013-01-01

    Correct characterization of focal solid hepatic lesions has always been a challenge and is of great diagnostic and therapeutic relevance. The purpose of this study was to determine the added value of hepatobiliary phase images in Gd-EOB-DTPA-enhanced magnetic resonance imaging (MRI) for differentiating focal solid hepatic lesions. In this retrospective trial 84 consecutive patients underwent Gd-EOB-DTPA-enhanced MR examinations. MRI was conducted for 64 patients with malignant focal hepatic lesions (34 hepatocellular carcinoma (HCC), 30 metastases) and for 20 patients with benign hepatic lesions (14 focal nodular hyperplasia (FNH), 3 adenoma, 3 hemangioma). Five radiologists independently reviewed three sets of MR images by means of a 5-point confidence scale from score 1 (definitely benign) to score 5 (definitely malignant): set 1: unenhanced images; set 2: unenhanced and Gd-EOB-DTPA-enhanced dynamic images; set 3: hepatobiliary phase images in addition to set 2. Accuracy was assessed by the alternative free-response receiver operating characteristic curve (A z ) and the index of diagnostic performance was calculated. Diagnostic accuracy was significantly improved by the addition of Gd-EOB-DTPA-enhanced dynamic images: A z in set 1 was 0.708 and 0.833 in set 2 (P = 0.0002). The addition of hepatobiliary phase images increased the A z value to 0.941 in set 3 (set 3 vs set 2, P < 0.0001; set 3 vs set 1, P < 0.0001). The index of diagnostic performance was lowest in set 1 (45%), improved in set 2 (71%), and highest in set 3 (94%). Hepatobiliary phase images obtained after Gd-EOB-DTPA-enhanced dynamic MRI improve the differentiation of focal solid hepatic lesions

  19. {sup 99m}Tc sestamibi imaging. Can it be a useful substitute for hepatobiliary scintigraphy in infantile jaundice?

    Energy Technology Data Exchange (ETDEWEB)

    Sadeghi, R.; Kakhki, V.R.D.; Zakavi, R. [Mashhad Univ. of Medical Sciences (Iran). Nuclear Medicine Dept.; Kianifar, H.R. [Mashhad Univ. of Medical Sciences (Iran). Paediatric Dept.; Ansari, K. [Tehran Univ. of Medical Sciences (Iran). Nuclear Medicine Dept.

    2009-07-01

    Hepatobiliary scintigraphy is an integral part in the diagnostic work-up of the neonatal cholestasis syndrome. However, less than optimal specificity is its major disadvantage. Differentiation between biliary atresia and neonatal hepatitis is nearly impossible in some cases with poor hepatocellular function. {sup 99m}Tc sestamibi (MIBI) is a cationic lipophilic agent which is a substrate of P-glycoprotein. This glycoprotein is normally expressed in biliary canalicular surfaces of hepatocytes. This property provides a hepatic excretory mechanism which is different from bilirubin excretion. In this study we evaluated the value of {sup 99m}Tc MIBI in differential diagnosis of neonatal cholestasis. 20 infants with a mean age of 2.41 months (range, 0.1-5 months) were included in the study. Ten infants turned out to have extrahepatic biliary atresia and the other ten had neonatal hepatitis. Hepatobiliary (with {sup 99m}Tc BrIDA) and {sup 99m}Tc MIBI scintigraphy were performed for all the patients. {sup 99m}Tc MIBI scintigraphy has shown bowel activity in all patients, including the patients with biliary atresia. Hepatobiliary scintigraphy revealed bowel activity only in five patients with neonatal hepatitis. Bowel visualization with {sup 99m}Tc MIBI may be seen in patients with biliary atresia and {sup 99m}Tc MIBI has limited value in differential diagnosis of neonatal cholestasis. (orig.)

  20. Comparative cardiac effects of three hepatobiliary radiopharmacologicals in the dog: concise communication

    International Nuclear Information System (INIS)

    Shani, J.; Sarel, O.; Rogel, S.; Weininger, J.; Lubin, E.

    1982-01-01

    Three hepatobiliary agents with an acetanilide-imidoacetic-acid moiety resembling that in lidocaine were investigated for their possible effects on contractility and conductivity in the heart and on arterial pressure and aortic blood flow. This was done in the light of lidocaine's numerous cardiac side effects. HIDA, BIDA, and DIPA, each with traces of decayed /sup 99m/Tc, were injected i.v. into anesthetized dogs with an A-V block, and their effects on the above parameters were followed until control levels were reestablished. Whereas lidocaine raises the diastolic threshold and prolongs the refractory period, the three agents tested do not prolong myocardial conductivity. Both HIDA and BIDA have an effect similar to that of lidocaine, but DIPA has no effect on the latter two parameters. Moreover, whereas lidocaine depressed myocardial contractility, blood pressure, and blood flow, HIDA has a less prominent effect on these parameters, and neither BIDA nor DIPA has any such effect. It is concluded that even though the effect of HIDA on the heart is milder than that of lidocaine, the effects of both BIDA and DIPA are even less pronounced, and they are less likely to cause cardiac side effects when similar doses are administered during nuclear medicine procedures

  1. Comparative cardiac effects of three hepatobiliary radiopharmacologicals in the dog: concise communication

    International Nuclear Information System (INIS)

    Shani, J.; Rogel, S.; Weininger, J.; Lubin, E.

    1982-01-01

    Three hepatobiliary agents with an acetanilide-imidoacetic-acid moiety resembling that in lidocaine were investigated for their possible effects on contractility and conductivity in the heart and on arterial pressure and aortic blood flow. This was done in the light of lidocaine's numerous cardiac side effects. HIDA, BIDA, and DIPA, each with traces of decayed Tc-99m, were injected i.v. into anesthetized dogs with an A-V block, and their effects on the above parameters were followed until control levels were reestablished. Wheras lidocaine raises the diastolic threshold and prolongs the refractory period, the three agents tested do not prolong myocardial conductivity. Both HIDA and BIDA have an effect similar to that of lidocaine, but DIPA has no effect on the latter two parameters. Moreover, whereas lidocaine depresses myocardial contractility, blood pressure, and blood flow, HIDA has a less prominent effect on these parameters, and neither BIDA nor DIPA has any such effect. It is concluded that even though the effect of HIDA on the heart is milder than that of lidocaine, the effects of both BIDA and DIPA are even less pronounced, and they are less likely to cause cardiac side effects when similar doses are administered during nuclear medicine procedures

  2. Hepatobiliary scintigraphy in the assessment of biliary obstruction after hepatic resection with biliary-enteric anastomosis

    Energy Technology Data Exchange (ETDEWEB)

    Kim, J.S.; Moon, D.H.; Shin, J.W.; Ryu, J.S.; Lee, H.K. [Department of Nuclear Medicine, Asan Medical Center, University of Ulsan College of Medicine, Seoul (Korea); Lee, S.G.; Lee, Y.J.; Park, K.M. [Department of General Surgery, Asan Medical Center, University of Ulsan College of Medicine, Seoul (Korea)

    2000-02-01

    We investigated the usefulness of hepatobiliary scintigraphy (HBS) for diagnosing biliary obstruction after curative hepatic resection with biliary-enteric anastomosis. The study population consisted of 54 patients who underwent surgery for benign (n=18) or malignant (n=36) biliary disease. We analysed 68 technetium-99m DISIDA scintigrams which were performed at least 1 month after the surgery (median: 9 months). Final diagnosis was made by operative exploration, other invasive radiological studies or clinical and radiological follow-up for at least 6 months after the surgery. Diagnostic accuracy was analysed according to the pretest likelihood of biliary obstruction. There were two total and 15 segmental biliary obstructions. In patients with symptoms of biliary obstruction and abnormal liver function, HBS always allowed correct diagnosis (two instances of total obstruction, seven of segmental obstruction and seven of non-obstruction). Among the patients with non-specific symptoms or isolated elevation of serum alkaline phosphatase, HBS diagnosed segmental biliary obstruction in seven of the eight instances, and non-obstruction in 22 of 23 instances. There were no cases of biliary obstruction and no false-positive results of HBS in 21 instances with no clinical signs or symptoms of biliary obstruction. The diagnostic sensitivity and specificity of HBS for biliary obstruction were 94% (16/17) and 97% (50/51), respectively. In conclusion, HBS is a highly accurate modality for the diagnosis of segmental biliary obstruction during long-term follow-up after hepatic resection with biliary-enteric anastomosis. (orig.)

  3. Hepatobiliary gammagraphy and its importance for differential diagnosis of mechanic and hepatocellular jaundice

    International Nuclear Information System (INIS)

    Takacs, J.

    1983-01-01

    The reliability of hepatobiliary gammagraphy following sup(99m)Tc-EHIDA administration and its variations with the concentration of the total plasma bilirubin were assessed in 155 hepatitis patients in whom differential diagnosis was performed for mechanical or hepatocellular jaundice. In mechanical jaundice (28 patients), sensitivity of the method was 75.8%, specificity 95.9%, diagnostic accuracy 90.9%. In hepatocellular jaundice (127 patients) the respective values were 95.9%, 90.3%, 94.8%. The differential diagnosis reliability was found to decrease with the increasing level of total bilirubin. For a level of up to 21.5 μmol/l, diagnostic accuracy was 93.6%, for a level between 21.6 and 85.5 μmol/l it was 91.0%, from 85.6 to 171.0 μmol/l it was 66.6%, from 171.1 to 242.0 μmol/l it was 50.0%, and above 242.0 μmol/l, diagnostic accuracy was 28.5%. At the same time, the sensitivity and specificity of examination decreased with increasing bilirubin level. In respect of differential diagnosis of jaundice, a concentration of the total plasma bilirubin of 242.O μmol/l is considered to be the limit concentration. (author)

  4. Sensitivity of hepatobiliary imaging and real-time ultrasonography in the detection of acute cholecystitis

    Energy Technology Data Exchange (ETDEWEB)

    Fink-Bennett, D.; Freitas, J.E.; Ripley, S.D.; Bree, R.L.

    1985-08-01

    To determine the sensitivity of hepatobiliary imaging (HBI) and strict- and liberal-criteria real-time ultrasonography (RTUS), the authors retrospectively analyzed 100 cases of pathologically proved acute cholecystitis (AC). A positive HBI was one in which there was nonvisualization of the gallbladder up to four hours after the administration of technetium 99m-disofenin. In the absence of hypoalbuminemia, cirrhosis, or ascites, pathognomonic RTUS findings (strict criteria) for AC were wall edema and/or pericholecystic fluid. Findings indicative of AC (liberal criteria) included the demonstration of stones, a thick gallbladder wall, nonshadowing echoes, or the ultrasonographic Murphy's sign. Of the 100 cases of AC, 91 were calculous, and nine were acalculous. Four of 100 patients had associated choledocholithiasis. The sensitivities in detecting calculous AC were as follows: HBI, 97%; liberal-criteria RTUS, 86%; and strict-criteria RTUS, 24%. The sensitivities in detecting acalculous AC were as follows: HBI, 100%; liberal-criteria RTUS, 89%; and strict-criteria RTUS, 44%.

  5. Sensitivity of hepatobiliary imaging and real-time ultrasonography in the detection of acute cholecystitis

    International Nuclear Information System (INIS)

    Fink-Bennett, D.; Freitas, J.E.; Ripley, S.D.; Bree, R.L.

    1985-01-01

    To determine the sensitivity of hepatobiliary imaging (HBI) and strict- and liberal-criteria real-time ultrasonography (RTUS), the authors retrospectively analyzed 100 cases of pathologically proved acute cholecystitis (AC). A positive HBI was one in which there was nonvisualization of the gallbladder up to four hours after the administration of technetium 99m-disofenin. In the absence of hypoalbuminemia, cirrhosis, or ascites, pathognomonic RTUS findings (strict criteria) for AC were wall edema and/or pericholecystic fluid. Findings indicative of AC (liberal criteria) included the demonstration of stones, a thick gallbladder wall, nonshadowing echoes, or the ultrasonographic Murphy's sign. Of the 100 cases of AC, 91 were calculous, and nine were acalculous. Four of 100 patients had associated choledocholithiasis. The sensitivities in detecting calculous AC were as follows: HBI, 97%; liberal-criteria RTUS, 86%; and strict-criteria RTUS, 24%. The sensitivities in detecting acalculous AC were as follows: HBI, 100%; liberal-criteria RTUS, 89%; and strict-criteria RTUS, 44%

  6. Cytologic diagnosis of hepatobiliary cystadenoma with mesenchymal stroma during intraoperative consultation: a case report.

    Science.gov (United States)

    Voltaggio, Lysandra; Szeto, Oliver J; Tabbara, Sana O

    2010-01-01

    Hepatobiliary cystadenoma with mesenchymal stroma (HCMS) is a rare cystic tumor characterized by a layer of mucinous cuboidal to columnar epithelium situated on top of a basement membrane resting on an ovarian-like stroma. Cytologic features of this entity have not been extensively studied. We present a case of HCMS with emphasis on cytologic material obtained at the time of intraoperative consultation (IOC). A 51-year-old woman had partial resection of a liver cyst. Seven months later she sought further medical attention and presented for surgical reevaluation and reexcision of the same lesion. Initial computed tomography revealed a multiloculated liver cyst. Five months after reexcision the lesion recurred and was again excised. During IOC, scrape cytology revealed both biliary epithelial and mesenchymal stromal cells in a cystic background. Permanent sections showed histologic features of HCMS. To the best of our knowledge, this is the first cytologic description of such a neoplasm to include both epithelial and mesenchymal stromal elements. The use of scrape cytology during IOC can be a fast and effective way of identifying both the epithelium and mesenchymal stroma when HCMS is in the differential diagnosis of a cystic liver lesion.

  7. Age dependence of spleen- and muscle-corrected hepatic signal enhancement on hepatobiliary phase gadoxetate MRI

    Energy Technology Data Exchange (ETDEWEB)

    Matoori, Simon [Paracelsus Medical University Salzburg, Department of Radiology, Salzburg (Austria); Hirslanden Clinic St. Anna, Clinical Research Group, Lucerne (Switzerland); Froehlich, Johannes M. [Hirslanden Clinic St. Anna, Clinical Research Group, Lucerne (Switzerland); ETH Zurich, Department of Chemistry and Applied Biosciences, Institute of Pharmaceutical Sciences, Zurich (Switzerland); Cantonal Hospital Winterthur, Department of Radiology, Winterthur (Switzerland); Breitenstein, Stefan [Cantonal Hospital Winterthur, Department of Surgery, Clinic for Visceral and Thoracic Surgery, Winterthur (Switzerland); Doert, Aleksis [Cantonal Hospital Winterthur, Department of Radiology, Winterthur (Switzerland); Pozdniakova, Viktoria [Stavanger University Hospital, Department of Radiology, Stavanger (Norway); Koh, Dow-Mu [Royal Marsden Hospital, Department of Radiology, Surrey, England (United Kingdom); Gutzeit, Andreas [Paracelsus Medical University Salzburg, Department of Radiology, Salzburg (Austria); Hirslanden Clinic St. Anna, Clinical Research Group, Lucerne (Switzerland); Cantonal Hospital Winterthur, Department of Radiology, Winterthur (Switzerland)

    2016-06-15

    To identify correlations of signal enhancements (SE) and SE normalized to reference tissues of the spleen, kidney, liver, musculus erector spinae (MES) and ductus hepatocholedochus (DHC) on hepatobiliary phase gadoxetate-enhanced MRI with patient age in non-cirrhotic patients. A heterogeneous cohort of 131 patients with different clinical backgrounds underwent a standardized 3.0-T gadoxetate-enhanced liver MRI between November 2008 and June 2013. After exclusion of cirrhotic patients, a cohort of 75 patients with no diagnosed diffuse liver disease was selected. The ratio of signal intensity 20 min post- to pre-contrast administration (SE) in the spleen, kidney, liver, MES and DHC, and the SE of the kidney, liver and DHC normalized to the reference tissues spleen or MES were compared to patient age. Patient age was inversely correlated with the liver SE normalized to the spleen and MES SE (both p < 0.001) and proportionally with the SE of the spleen (p = 0.043), the MES (p = 0.030) and the kidney (p = 0.022). No significant correlations were observed for the DHC (p = 0.347) and liver SE (p = 0.606). The age dependence of hepatic SE normalized to the enhancement in the spleen and MES calls for a cautious interpretation of these quantification methods. (orig.)

  8. Hepatobiliary scintigraphy in the assessment of biliary obstruction after hepatic resection with biliary-enteric anastomosis

    International Nuclear Information System (INIS)

    Kim, J.S.; Moon, D.H.; Shin, J.W.; Ryu, J.S.; Lee, H.K.; Lee, S.G.; Lee, Y.J.; Park, K.M.

    2000-01-01

    We investigated the usefulness of hepatobiliary scintigraphy (HBS) for diagnosing biliary obstruction after curative hepatic resection with biliary-enteric anastomosis. The study population consisted of 54 patients who underwent surgery for benign (n=18) or malignant (n=36) biliary disease. We analysed 68 technetium-99m DISIDA scintigrams which were performed at least 1 month after the surgery (median: 9 months). Final diagnosis was made by operative exploration, other invasive radiological studies or clinical and radiological follow-up for at least 6 months after the surgery. Diagnostic accuracy was analysed according to the pretest likelihood of biliary obstruction. There were two total and 15 segmental biliary obstructions. In patients with symptoms of biliary obstruction and abnormal liver function, HBS always allowed correct diagnosis (two instances of total obstruction, seven of segmental obstruction and seven of non-obstruction). Among the patients with non-specific symptoms or isolated elevation of serum alkaline phosphatase, HBS diagnosed segmental biliary obstruction in seven of the eight instances, and non-obstruction in 22 of 23 instances. There were no cases of biliary obstruction and no false-positive results of HBS in 21 instances with no clinical signs or symptoms of biliary obstruction. The diagnostic sensitivity and specificity of HBS for biliary obstruction were 94% (16/17) and 97% (50/51), respectively. In conclusion, HBS is a highly accurate modality for the diagnosis of segmental biliary obstruction during long-term follow-up after hepatic resection with biliary-enteric anastomosis. (orig.)

  9. A novel combined interventional radiologic and hepatobiliary surgical approach to a complex traumatic hilar biliary stricture

    Directory of Open Access Journals (Sweden)

    Rachel E. NeMoyer

    Full Text Available Introduction: Benign strictures of the biliary system are challenging and uncommon conditions requiring a multidisciplinary team for appropriate management. Presentation of case: The patient is a 32-year-old male that developed a hilar stricture as sequelae of a gunshot wound. Due to the complex nature of the stricture and scarring at the porta hepatis a combined interventional radiologic and surgical approach was carried out to approach the hilum of the right and left hepatic ducts. The location of this stricture was found by ultrasound guidance intraoperatively using a balloon tipped catheter placed under fluoroscopy in the interventional radiology suite prior to surgery. This allowed the surgeons to select the line of parenchymal transection for best visualization of the stricture. A left hepatectomy was performed, the internal stent located and the right hepatic duct opened tangentially to allow a side-to-side Roux-en-Y hepaticojejunostomy (a Puestow-like anastomosis. Discussion: Injury to the intrahepatic biliary ductal confluence is rarely fatal, however, the associated injuries lead to severe morbidity as seen in this example. Management of these injuries poses a considerable challenge to the surgeon and treating physicians. Conclusion: Here we describe an innovative multi-disciplinary approach to the repair of this rare injury. Keywords: Combined approach, Interventional radiology, Hepatobiliary surgery, Complex traumatic hilar biliary stricture, Case report

  10. Kinetic Typography

    DEFF Research Database (Denmark)

    van Leeuwen, Theo; Djonov, Emilia

    2014-01-01

    After discussing broad cultural drivers behind the development of kinetic typography, the chapter outlines an approach to analysing kinetic typography which is based on Halliday's theory of transitivity, as applied by Kress and Van Leeuwen to visual images....

  11. Kinetic Typography

    DEFF Research Database (Denmark)

    van Leeuwen, Theo; Djonov, Emilia

    2014-01-01

    After discussing broad cultural drivers behind the development of kinetic typography, the chapter outlines an approach to analysing kinetic typography which is based on Halliday's theory of transitivity, as applied by Kress and Van Leeuwen to visual images.......After discussing broad cultural drivers behind the development of kinetic typography, the chapter outlines an approach to analysing kinetic typography which is based on Halliday's theory of transitivity, as applied by Kress and Van Leeuwen to visual images....

  12. Clinical implications of hepatobiliary scintigraphy and ultrasound in the diagnosis of acute cholecystitis.

    Science.gov (United States)

    Rodriguez, Limael E; Santaliz-Ruiz, Luis E; De La Torre-Bisot, Gabriel; Gonzalez, Giovanni; Serpa, Miguel A; Sanchez-Gaetan, Felipe; Martinez-Trabal, Jorge L; Peguero-Rivera, Julio A; Bolanos-Avila, Guillermo

    2016-11-01

    We assess the performance of ultrasound (US) and hepatobiliary scintigraphy (HIDA) as confirmatory studies in acute cholecystitis (AC) and demonstrate our current imaging protocol's impact on outcomes. Between January 2013 to July 2014, 117 patients were admitted through the emergency room with a preliminary diagnosis of AC. Overall, 106/117 (91%) of the patients received US preadmission and 34/117 (29%) received a HIDA post admission. Primary end points included: 1) diagnostic test reliability for AC, and 2) outcome and quality measures (time to surgery, LOS, costs, etc.). Laparoscopic cholecystectomy was performed in 96/117 (82%) and open cholecystectomy in 21/117 (18%) of the patients. Overall, histopathologic features consistent with AC was present in 46/117 (39%). AC alone was present in 23/117 (20%), and AC superimposed on chronic cholecystitis was present in 23/117 (20%). For AC, US had a sensitivity and specificity of 26% and 80%, respectively. HIDA scan had a sensitivity and specificity of 87% and 79%, respectively. Time to surgery (TTS) was 4 vs 2.3 days in patients who received HIDA vs US alone (p = 0.001), and length of stay (LOS) was 6.7 vs 4.3 days, respectively (p = 0.001). Age >50 years, glucose >140 (mg/dl), and WBC count >10 (×10 9 /L) were statistically significant independent variables associated with AC. HIDA scan is superior to US as a diagnostic study in the setting of AC. Our current protocol of delayed HIDA (post-admission) was associated with increased TTS, LOS, and overall costs. Early confirmation with HIDA in high risk patients may hasten treatment allocation and improve outcomes in the setting of AC. Copyright © 2016 IJS Publishing Group Ltd. Published by Elsevier Ltd. All rights reserved.

  13. Dose and batch-dependent hepatobiliary toxicity of 10 nm silver nanoparticles

    Directory of Open Access Journals (Sweden)

    Marcella De Maglie

    2015-07-01

    Full Text Available Silver nanoparticles (AgNPs are widely used because of their antimicrobial properties in medical devices and in a variety of consumer products. The extensive use of AgNPs raises concerns about their potential toxicity, although it is still difficult to draw definite conclusions about their toxicity based on published data. Our preliminary studies performed to compare the effect of the AgNPs size (10-40-100 nm on toxicity, demonstrated that the smallest AgNPs determine the most severe toxicological effects. In order to best investigate the impact of physicochemical characteristics of 10 nm AgNPs on toxicity, we compare three different batches of 10 nm AgNPs slightly different in size distribution (Batch A: 8.8±1.7 nm; Batch B: 9.4±1.7 nm; Batch C: 10.0±1.8 nm. Mice were intravenously treated with two doses (5 and 10 mg/kg of the 3 AgNPs. 24 hours after the treatment, mice were euthanized and underwent complete necropsy. Tissues were collected for histopathological examination and total silver content was determined in tissues by inductively coupled plasma mass spectrometry (ICP-MS. All batches induced severe hepatobiliary lesions, i.e. marked hepatocellular necrosis and massive hemorrhage of the gall bladder. The toxicity was dose-dependent and interestingly, the toxic effects were more severe in mice treated with batches A and B that contained smaller AgNPs. Since the total silver mass concentration was similar, the observed batch-dependent toxicity suggest that even subtle differences in size may contribute to relevant changes in the toxicological outcomes, confirming the fundamental involvement of physicochemical features with respect to toxicity.

  14. Prior inpatient admission increases the risk of post-operative infection in hepatobiliary and pancreatic surgery.

    Science.gov (United States)

    Dong, Zachary M; Chidi, Alexis P; Goswami, Julie; Han, Katrina; Simmons, Richard L; Rosengart, Matthew R; Tsung, Allan

    2015-12-01

    Hepatobiliary and pancreatic (HPB) operations have a high incidence of post-operative nosocomial infections. The aim of the present study was to determine whether hospitalization up to 1 year before HPB surgery is associated with an increased risk of post-operative infection, surgical-site infection (SSI) and infection resistant to surgical chemoprophylaxis. A retrospective cohort study of patients undergoing HPB surgeries between January 2008 and June 2013 was conducted. A multivariable logistic regression model was used for controlling for potential confounders to determine the association between pre-operative admission and post-operative infection. Of the 1384 patients who met eligibility criteria, 127 (9.18%) experienced a post-operative infection. Pre-operative hospitalization was independently associated with an increased risk of a post-operative infection [adjusted odds ratio (aOR): 1.61, 95% confidence interval [CI]: 1.06-2.46] and SSI (aOR: 1.79, 95% CI: 1.07-2.97). Pre-operative hospitalization was also associated with an increased risk of post-operative infections resistant to standard pre-operative antibiotics (OR: 2.64, 95% CI: 1.06-6.59) and an increased risk of resistant SSIs (OR: 3.99, 95% CI: 1.25-12.73). Pre-operative hospitalization is associated with an increased incidence of post-operative infections, often with organisms that are resistant to surgical chemoprophylaxis. Patients hospitalized up to 1 year before HPB surgery may benefit from extended spectrum chemoprophylaxis. © 2015 International Hepato-Pancreato-Biliary Association.

  15. Overcoming obstacles to establish a multidisciplinary team approach to hepatobiliary diseases: a working model in a Caribbean setting.

    Science.gov (United States)

    Cawich, Shamir O; Johnson, Peter B; Shah, Sundeep; Roberts, Patrick; Arthurs, Milton; Murphy, Trevor; Bonadie, Kimon O; Crandon, Ivor W; Harding, Hyacinth E; Abu Hilal, Mohammed; Pearce, Neil W

    2014-01-01

    By providing a structured forum to exchange information and ideas, multidisciplinary team meetings improve working relationships, expedite investigations, promote evidence-based treatment, and ultimately improve clinical outcomes. This discursive paper reports the introduction of a multidisciplinary team approach to manage hepatobiliary diseases in Jamaica, focusing on the challenges encountered and the methods used to overcome these obstacles. Despite multiple challenges in resource-limited environments, a multidisciplinary team approach can be incorporated into clinical practice in developing nations. Policy makers should make it a priority to support clinical, operational, and governance aspects of the multidisciplinary teams.

  16. Comparison of the dynamics of bile emptying by quantitative hepatobiliary scintigraphy before and after cholecystectomy in patients with uncomplicated gallstone disease

    DEFF Research Database (Denmark)

    Madácsy, L; Toftdahl, D B; Middelfart, H V

    1999-01-01

    PURPOSE: Quantitative hepatobiliary scintigraphy, a noninvasive method frequently used to diagnose several biliary tract disorders, shows abnormalities in bile secretion and outflow. It is well known that there are wide variations in the normal pattern of bile emptying, but the effect of cholecys......PURPOSE: Quantitative hepatobiliary scintigraphy, a noninvasive method frequently used to diagnose several biliary tract disorders, shows abnormalities in bile secretion and outflow. It is well known that there are wide variations in the normal pattern of bile emptying, but the effect...

  17. Kinetic sculpture

    OpenAIRE

    Joneta Witabora; Jonata Witabora

    2014-01-01

    Kinetic Sculpture was born from a long process of searching new approach in sculpture. The artists tried to escape from 'static' paradigm and tried to implement movement into their works: a sculpture that is mobile. Movement is always a fascinating phenomenon to eyes. Kinetic sculpture strength lies in its unique character in combining science and art. Kinetic Sculptures are really interesting pieces of art. It succeeds to fascinate human everytime. 

  18. Early phase detection of bile leak after hepatobiliary surgery: value of Gd-EOB-DTPA-enhanced MR cholangiography.

    Science.gov (United States)

    Alegre Castellanos, Alvaro; Molina Granados, Juan Felix; Escribano Fernandez, Jose; Gallardo Muñoz, Inmaculada; Triviño Tarradas, Francisco de Asis

    2012-10-01

    To assess the value of gadolinium ethoxybenzyl diethylenetriamine pentaacetic acid (Gd-EOB-DTPA)-enhanced MR cholangiography for the detection of bile leaks after hepatobiliary surgery. Twenty-three patients with symptoms suggestive of bile leak underwent conventional fat-suppressed T1- and T2-weighted MR cholangiography followed by Gd-EOB-DTPA-enhanced MR cholangiography using gradient-echo (GRE) T2-weighted sequences and fat-suppressed T1-weighted 3D gradient-echo sequences 20 min after an intravenous bolus of Gd-EOB-DTPA. The results of Gd-EOB-DTPA-enhanced MR cholangiography correlated with clinical findings, surgical repair, and the results of endoscopic retrograde cholangiopancreatography and percutaneous transhepatic cholangiography. The results of Gd-EOB-DTPA-enhanced MR cholangiography were negative in 13 patients (cholecystectomy 5, liver transplantation 2, liver resection for focal lesions 2, cholangiocarcinoma 1, and partial hepatectomy after liver injury 1). In 10 patients in whom bile leaks were detected, this complication occurred after liver resection for focal lesions in 3, cholecystectomy in 4, liver transplantation in 2, and liver resection for intrahepatic cholangiocarcinoma in 1. The diagnostic accuracy of Gd-EOB-DTPA-enhanced MR for the detection or exclusion of bile leaks was 100%. Gd-EOB-DTPA-enhanced MR cholangiography is a highly reliable technique for the detection of bile leaks after hepatobiliary surgery and may avoid the use of other, potentially risky invasive diagnostic techniques.

  19. Kinetic approach

    Indian Academy of Sciences (India)

    Collapse of a Bose gas: Kinetic approach ... Thermodynamical, statistical and static properties of condensates; Ultracold and trapped gases; matter waves. ... of a harmonically trapped attractively interacting Bose gas below the condensation point by introducing a kinetic approach within the Hartee-Fock approximation.

  20. Heparin kinetics

    International Nuclear Information System (INIS)

    Swart, C.A.M. de.

    1983-01-01

    The author has studied the kinetics of heparin and heparin fractions after intravenous administration in humans and in this thesis the results of this study are reported. Basic knowledge about the physico-chemical properties of heparin and its interactions with proteins resulting in anticoagulant and lipolytic effects are discussed in a review (chapter II), which also comprises some clinical aspects of heparin therapy. In chapter III the kinetics of the anticoagulant effect are described after intravenous administration of five commercial heparin preparations. A mathematical model is presented that fits best to these kinetics. The kinetics of the anticoagulant and lipolytic effects after intravenous injection of various 35 S-radiolabelled heparin fractions and their relationship with the disappearance of the radiolabel are described in chapter IV. Chapter V gives a description of the kinetics of two radiolabels after injection of in vitro formed complexes consisting of purified, 125 I-radiolabelled antithrombin III and various 35 S-radiolabelled heparin fractions. (Auth.)

  1. Contrast-enhanced free-breathing 3D T1-weighted gradient-echo sequence for hepatobiliary MRI in patients with breath-holding difficulties.

    Science.gov (United States)

    Reiner, C S; Neville, A M; Nazeer, H K; Breault, S; Dale, B M; Merkle, E M; Bashir, M R

    2013-11-01

    Evaluate the image quality and diagnostic performance of a free-breathing 3D-gradient-echo sequence with radial acquisition (rGRE) compared with a Cartesian breath-hold 3D-GRE (cGRE) sequence on hepatobiliary phase MRI in patients with breath-holding difficulties. Twenty-eight consecutive patients (15 males; mean age 61 ± 11.9 years) were analysed in this retrospective IRB-approved study. Breath-holding difficulties during gadoxetate-disodium-enhanced liver MRI manifested as breathing artefacts during dynamic-phase imaging. MRI included axial and coronal cGRE and a radially sampled rGRE sequence during the hepatobiliary phase. Two radiologists independently evaluated cGRE and rGRE images for image quality, liver lesion detection and conspicuity, and bile duct conspicuity on a four-point scale. Liver edge sharpness was significantly higher on rGRE images (P breath-holding difficulties, overall image quality and liver lesion conspicuity on hepatobiliary phase MRI can be improved using the rGRE sequence. • Patients with diminished breath-holding capacities present a major challenge in abdominal MRI. • A free-breathing sequence for hepatobiliary-phase MRI can improve image quality. • Further advances are needed to reduce acquisition time of the free-breathing gradient-echo sequence.

  2. Relationship between signal intensity on hepatobiliary phase of gadolinium ethoxybenzyl diethylenetriaminepentaacetic acid (Gd-EOB-DTPA)-enhanced MR imaging and prognosis of borderline lesions of hepatocellular carcinoma

    Energy Technology Data Exchange (ETDEWEB)

    Kobayashi, Satoshi, E-mail: satoshik@staff.kanazawa-u.ac.jp [Department of Radiology, Kanazawa University School of Medicine, 13-1, Takara Machi, Kanazawa 920-8641 (Japan); Matsui, Osamu, E-mail: matsuio@med.kanazawa-u.ac.jp [Department of Radiology, Kanazawa University School of Medicine, 13-1, Takara Machi, Kanazawa 920-8641 (Japan); Gabata, Toshifumi, E-mail: gabata@med.kanazawa-u.ac.jp [Department of Radiology, Kanazawa University School of Medicine, 13-1, Takara Machi, Kanazawa 920-8641 (Japan); Koda, Wataru, E-mail: wkoda@staff.kanazawa-u.ac.jp [Department of Radiology, Kanazawa University School of Medicine, 13-1, Takara Machi, Kanazawa 920-8641 (Japan); Minami, Tetsuya, E-mail: tminami@staff.kanazawa-u.ac.jp [Department of Radiology, Kanazawa University School of Medicine, 13-1, Takara Machi, Kanazawa 920-8641 (Japan); Ryu, Yasuji, E-mail: yryu-kanazawa@umin.ac.jp [Department of Radiology, Kanazawa University School of Medicine, 13-1, Takara Machi, Kanazawa 920-8641 (Japan); Kozaka, Kazuto, E-mail: k-kozaka@staff.kanazawa-u.ac.jp [Department of Radiology, Kanazawa University School of Medicine, 13-1, Takara Machi, Kanazawa 920-8641 (Japan); Kitao, Azusa, E-mail: azusa@med.kanazawa-u.ac.jp [Department of Radiology, Kanazawa University School of Medicine, 13-1, Takara Machi, Kanazawa 920-8641 (Japan)

    2012-11-15

    Purpose: To elucidate the incidence of signal intensity patterns of borderline lesions of hepatocellular carcinoma (HCC) on hepatobiliary phase Gd-EOB-DTPA (EOB) enhanced MRI and clarify the natural histories of these lesions. Materials and methods: Total 99 borderline lesions of HCC were identified by angiography-assisted CT. The signal intensity of borderline lesions on hepatobiliary phase of EOB-enhanced MRI was analyzed. Progress rate from borderline lesions to hypervascular HCC was calculated with the Kaplan-Meier method among each signal intensity groups of nodules. Results: On hepatobiliary phase of EOB-enhanced MRI, 41.4% of the borderline lesions showed hypo-, 42.4% showed iso-, and 16.2% showed hyperintense, compared to background liver. Overall progress rates from borderline lesions to HCC were 10% in 1-year, 14% in 2-year and 20% in 3-year follow-up period. Progress rates to HCC in hypointense borderline lesions were 17% in 1-year, 28% in 2-year and 41% in 3-year follow-up period, and in isointense borderline lesions were 7% in 1-year, 7% in 2-year and 7% in 3-year follow-up period. No hyperintense borderline lesions progressed to HCC in follow-up period. Conclusion: Although borderline lesions of HCC may show hypo-, iso- and hyperintensity on hepatobiliary phase of EOB-enhanced MRI, hypointense borderline lesions are high risk to progress HCC.

  3. Epithelioid hemangioendothelioma of the liver: the role of hepatobiliary phase imaging for the preoperative diagnosis and qualification of patients for liver transplantation -- preliminary experience.

    Science.gov (United States)

    Cieszanowski, Andrzej; Pacho, Ryszard; Anysz-Grodzicka, Agnieszka; Gornicka, Barbara; Remiszewski, Piotr; Maj, Edyta; Grudzinski, Ireneusz P; Zieniewicz, Krzysztof; Oldakowska-Jedynak, Urszula; Rowinski, Olgierd; Krawczyk, Marek

    2013-08-19

    The aim of this study was to determine if the appearance of hepatic epithelioid hemangioendothelioma (HEHE) on state-of-the-art MRI including hepatocyte phase after administration of hepatobiliary contrast agent can facilitate preoperative diagnosis and identification of potential candidates for liver transplantation. The study group comprised 6 patients with pathologically confirmed HEHE. Analysis included signal characteristics of 55 tumor nodules (maximum of 10 lesions per patient) on T2-weighted images, dynamic contrast-enhanced, 5-minute delayed, and hepatobiliary phase images. The most common feature of HEHE, observed in 84% of lesions, was progressive contrast-enhancement, followed by subcapsular location (66%), confluent appearance (60%) and hyper- or isointensity on hepatobiliary phase images (53%). In 5 of 6 patients, capsular retraction was observed. The appearance of HEHE on hepatobiliary phase images was variable, but examined tumors often demonstrated hyper- or isointensity, most probably due to prolonged retention of contrast material. These features, along with typical morphology (subcapsular, confluent nodules, with progressive enhancement and capsular retraction), may contribute to correct diagnosis and recognition of potential candidates for liver transplantation.

  4. Kinetic Interface

    DEFF Research Database (Denmark)

    2009-01-01

    A kinetic interface for orientation detection in a video training system is disclosed. The interface includes a balance platform instrumented with inertial motion sensors. The interface engages a participant's sense of balance in training exercises.......A kinetic interface for orientation detection in a video training system is disclosed. The interface includes a balance platform instrumented with inertial motion sensors. The interface engages a participant's sense of balance in training exercises....

  5. The Impact of New Technologic and Molecular Advances in the Daily Practice of Gastrointestinal and Hepatobiliary Pathology.

    Science.gov (United States)

    Xue, Yue; Farris, Alton Brad; Quigley, Brian; Krasinskas, Alyssa

    2017-04-01

    The practice of anatomic pathology, and of gastrointestinal pathology in particular, has been dramatically transformed in the past decade. In addition to the multitude of diseases, syndromes, and clinical entities encountered in daily clinical practice, the increasing integration of new technologic and molecular advances into the field of gastroenterology is occurring at a fast pace. Application of these advances has challenged pathologists to correlate newer methodologies with existing morphologic criteria, which in many instances still provide the gold standard for diagnosis. This review describes the impact of new technologic and molecular advances on the daily practice of gastrointestinal and hepatobiliary pathology. We discuss new drugs that can affect the gastrointestinal tract and liver, new endoluminal techniques, new molecular tests that are often performed reflexively, new imaging techniques for evaluating hepatocellular carcinoma, and modified approaches to the gross and histologic assessment of tissues that have been exposed to neoadjuvant therapies.

  6. Functional scintiscanning with sup(99m)technetium-diethyl-HIDA as a nuclear diagnostical means in hepatobiliary diseases

    International Nuclear Information System (INIS)

    Hummel, G.

    1982-01-01

    The study aimed to delimit the value of sequential hepatobiliary scintiscanning with the aid of sup(99m)technetium-diethyl-HIDA as a diagnostical method in functional or morphological disorders of the gall bladder and bile ducts. The most frequent indications to carry through the investigation therefore were inflammations calculosis in the biliary system, suspected intrahepatic icterus or conditions following biliodigestive anastomoses. Special attention was directed to the question in how far the results were in accordance with those of x-ray cholecystography/cholangiography. Furthermore the possibility for semiquantitative evaluation of serial functional scintiscanning was looked into and clearance determinations were carried through in part of the patients investigated. (orig./MG) [de

  7. Prognostic impact of hepatobiliary scintigraphy in diagnosis and postoperative follow-up of newborns with biliary atresia

    International Nuclear Information System (INIS)

    Rossmueller, B.; Porn, U.; Dresel, S.; Hahn, K.; Schuster, T.; Lang, T.

    2000-01-01

    Aim: To investigate the prognostic relevance of hepatobiliary scintigraphy (HBS) in newborns suffering from biliary atresia (BA) for establishing the primary diagnosis and in the postoperative follow-up after portoenterostomy (Kasai). Methods: Twenty newborns with direct hyperbilirubinemia and 6 children after operative treatment of BA (Kasai) underwent HBS with Tc-99m-DEIDA. In patients without intestinal drainage, hepatocellular extraction was estimated visually and calculated semiquantitatively by means of liver/heart-ratio 5 min p.i. Results: 10/20 patients with hyperbilirubinemia did not display biliary drainage; 6 had BA, 3 intrahepatic hypoplasia, and one showed a bile plug syndrom. 4/6 with BA but none of the 4 children with diagnoses other than BA presented with a good extraction. All of the 4 children with BA, who had either pre- or postoperatively a bad extraction, needed liver transplantation due to liver failure. Both of the two newborns with BA and favourable outcome after Kasai had a good extraction in the preoperative HBS and demonstrated good intestinal drainage in the postoperative scan. Conclusion: HBS rules out BA with high accuracy by demonstrating drainage of bile into the intestine. In newborns without drainage a good extraction favours the diagnosis of BA. In newborns with BA a bad extraction seems to indicate a poor postoperative prognosis after Kasai operation. HBS might therefore help to select those children who will not benefit from portoenterostomy. Postoperatively, HBS can easily and quickly confirm the successful hepatobiliary anastomosis by demonstrating biliary drainage into the intestine. (orig.) [de

  8. Kinetics and

    Directory of Open Access Journals (Sweden)

    Mojtaba Ahmadi

    2016-11-01

    Full Text Available The aqueous degradation of Reactive Yellow 84 (RY84 by potassium peroxydisulfate (K2S2O8 has been studied in laboratory scale experiments. The effect of the initial concentrations of potassium peroxydisulfate and RY84, pH and temperature on RY84 degradation were also examined. Experimental data were analyzed using first and second-order kinetics. The degradation kinetics of RY84 of the potassium peroxydisulfate process followed the second-order reaction kinetics. These rate constants have an extreme values similar to of 9.493 mM−1min−1 at a peroxydisulfate dose of 4 mmol/L. Thermodynamic parameters such as activation (Ea and Gibbs free energy (ΔG° were also evaluated. The negative value of ΔGo and Ea shows the spontaneous reaction natural conditions and exothermic nature.

  9. Kinetic bridges.

    Science.gov (United States)

    1980-01-01

    This report on kinetic bridges is essentially a state-of-the-art study on two types of bridges whose location or physical characteristics are designed to be time dependent. The first type, called a "relocatable bridge", is essentially for use as a te...

  10. The target sign in colorectal liver metastases: an atypical Gd-EOB-DTPA "uptake" on the hepatobiliary phase of MR imaging.

    Science.gov (United States)

    Granata, Vincenza; Catalano, Orlando; Fusco, Roberta; Tatangelo, Fabiana; Rega, Daniela; Nasti, Guglielmo; Avallone, Antonio; Piccirillo, Mauro; Izzo, Francesco; Petrillo, Antonella

    2015-10-01

    To describe the MRI findings in colorectal cancer liver metastases using gadoxetic acid (Gd-EOB-DTPA), with special emphasis on the target feature seen on the hepatobiliary phase. The medical records of 45 colorectal cancer patients with an overall number of 150 liver metastases were reviewed. All patients underwent Gd-EOB-DTPA-enhanced MRI before any kind of treatment. We retrospectively evaluated, for each lesion, the signal intensity on the T1-weighted, T2-weighted, and diffusion-weighted images. Additionally, the enhancement pattern during the arterial-, portal-, equilibrium-, and hepatobiliary-phase was assessed. Fourteen lesions had a pathological correlation. Lesions size was 5-40 mm (mean 15 mm). All metastases were hypointense on T1-w imaging. Ninety-nine lesions (66%) had a central area of very high signal intensity on T2-w imaging. Fifty-one metastases (34%) were hyperintense on the T2-w images. In DWI, all lesions had a restricted diffusion. The mean ADC value was 1.31 × 10(-3) mm(2)/s (range 1.10-1.45 × 10(-3) mm(2)/s). During the arterial-phase imaging, 61 lesions (41%) showed a rim enhancement, while 89 lesions (59%) appeared as hypointense. All lesions had low signal intensity in the portal and equilibrium phase. Thirty-nine percent of the lesions also showed an enhancing rim on the portal-phase images. During the hepatobiliary phase, 80 lesions (53.3%) were hypointense, while 70 lesions (46.7%) had a target appearance. A number of metastases show an atypical contrast medium uptake during the hepatobiliary phase of gadoxetic acid-enhanced MRI, consisting in a target appearance.

  11. Management of subcentimetre arterially enhancing and hepatobiliary hypointense lesions on gadoxetic acid-enhanced MRI in patients at risk for HCC.

    Science.gov (United States)

    Park, Chae Jung; An, Chansik; Park, Sumi; Choi, Jin-Young; Kim, Myeong-Jin

    2018-04-01

    To investigate the significance of subcentimetre (≤1 cm) arterially enhancing and hepatobiliary hypointense lesions (SAELs) observed on gadoxetic acid-enhanced magnetic resonance imaging (MRI) of patients at risk of hepatocellular carcinoma (HCC). A SAEL was defined as a subcentimetre hypervascular nodule exhibiting a hepatobiliary phase defect on gadoxetic acid-enhanced MRI. We included 52 SAELs from 46 patients in a HCC surveillance population. The HCC reference standard was pathologic confirmation or a nodule >1 cm with typical imaging features of HCC at follow-up imaging. The malignancy rate and HCC-favourable imaging findings of SAELs were evaluated. The malignancy rate among SAELs was 57.7% (30/52). At diagnosis, all SAELs that progressed to overt HCC were treatable with curative intention. Venous or late dynamic phase washout was more frequently observed with malignant SAELs than with benign SAELs (57.7% vs. 30.6%; P = 0.01). If SAELs exhibiting washout were considered as HCC, sensitivity, specificity, and positive predictive value was 83.3%, 50%, and 69.4%, respectively. Among patients at risk of HCC, SAELs on gadoxetic acid-enhanced MRI exhibited high malignant potential. However, close observation may be an appropriate strategy for isolated SAELs. A washout appearance may be helpful for predicting malignancy. • Gadoxetic acid-enhanced MRI provides hepatobiliary phase (HBP) images. • Screening frequently detects subcentimetre arterially enhancing and hepatobiliary hypointense lesions (SAELs). • A majority of SAELs progressed to overt HCC within 2 years. • A venous-phase washout appearance correlated significantly with malignancy in SAELs.

  12. Agreement between microscopic examination and bacterial culture of bile samples for detection of bactibilia in dogs and cats with hepatobiliary disease.

    Science.gov (United States)

    Pashmakova, Medora B; Piccione, Julie; Bishop, Micah A; Nelson, Whitney R; Lawhon, Sara D

    2017-05-01

    OBJECTIVE To evaluate the agreement between results of microscopic examination and bacterial culture of bile samples from dogs and cats with hepatobiliary disease for detection of bactibilia. DESIGN Cross-sectional study. ANIMALS 31 dogs and 21 cats with hepatobiliary disease for which subsequent microscopic examination and bacterial culture of bile samples was performed from 2004 through 2014. PROCEDURES Electronic medical records of included dogs and cats were reviewed to extract data regarding diagnosis, antimicrobials administered, and results of microscopic examination and bacterial culture of bile samples. Agreement between these 2 diagnostic tests was assessed by calculation of the Cohen κ value. RESULTS 17 (33%) dogs and cats had bactibilia identified by microscopic examination of bile samples, and 11 (21%) had bactibilia identified via bacterial culture. Agreement between these 2 tests was substantial (percentage agreement [positive and negative results], 85%; κ = 0.62; 95% confidence interval, 0.38 to 0.89) and improved to almost perfect when calculated for only animals that received no antimicrobials within 24 hours prior to sample collection (percentage agreement, 94%; κ = 0.84; 95% confidence interval, 0.61 to 1.00). CONCLUSIONS AND CLINICAL RELEVANCE Results indicated that agreement between microscopic examination and bacterial culture of bile samples for detection of bactibilia is optimized when dogs and cats are not receiving antimicrobials at the time of sample collection. Concurrent bacterial culture and microscopic examination of bile samples are recommended for all cats and dogs evaluated for hepatobiliary disease.

  13. Utility of Tc99m-Mebrofenin hepato-biliary scintigraphy (HIDA scan) for the diagnosis of biliary atresia.

    Science.gov (United States)

    Shah, Ira; Bhatnagar, Sushmita; Rangarajan, Venkatesh; Patankar, Nikhil

    2012-01-01

    To determine the utility of Tc99m-Mebrofenin hepato-biliary scintigraphy (HIDA scan) for diagnosis of biliary atresia in patients with neonatal cholestasis. Our study involves the retrospective analysis of 46 patients with neonatal cholestasis who underwent HIDA scans at the Pediatric Hepatobiliary Clinic, BJ Wadia Hospital for Children from May 2005 to July 2007. Biliary atresia (BA) was diagnosed on the basis of intra-operative cholangiogram. Non-BA patients were included in the neonatal hepatitis (NH) group. All patients received phenobarbitone and ursodeoxycholic acid for 5 days, prior to the HIDA scan. The HIDA scan was evaluated on the basis of uptake of the radioactive tracer by the liver at 5 minutes after intravenous injection; retention of radioactive tracer within the liver at 24 hours after injection and visualization of excretion of tracer into the intestine upto 24 hours after administration. The results of the HIDA scans were analyzed and correlated with the final diagnosis, gender and age of the patients. Chi-square test was employed for statistical analysis. The age of presentation of our patients ranged from 5 days to 6 months. The male: female ratio was 37:9. Of the total 46 patients, 28 had BA and 18 had NH. All 28 (100%) patients diagnosed with BA showed persistent radiotracer in the liver at 24 hours whereas 17 (94.4%) of the 18 NH patients showed hepatic radiotracer retention (p = 0.207), the difference being statistically insignificant. Twenty two (78.6%) patients of BA showed no excretion of the radiotracer at 24 hours whereas only 7 (38.9%) of the NH group did not excrete the radiotracer (p = 0.007), which was statistically significant. Neither the sex nor the age of the child contributed to any difference on the hepatic retention (p = 0.618 and 0.235, respectively) or on the intestinal excretion (p = 0.307 and 0.9, respectively) of the radiotracer. HIDA scan is a useful tool for screening of biliary atresia in patients with neonatal

  14. Hepatobiliary magnetic resonance imaging in patients with liver disease: correlation of liver enhancement with biochemical liver function tests

    Energy Technology Data Exchange (ETDEWEB)

    Kukuk, Guido M.; Schaefer, Stephanie G.; Hadizadeh, Dariusch R.; Schild, Hans H.; Willinek, Winfried A. [University of Bonn, Department of Radiology, Bonn (Germany); Fimmers, Rolf [University of Bonn, Department of Medical Biometry, Informatics and Epidemiology, Bonn (Germany); Ezziddin, Samer [Department of Nuclear Medicine, Bonn (Germany); Spengler, Ulrich [Department of Internal Medicine I, Bonn (Germany)

    2014-10-15

    To evaluate hepatobiliary magnetic resonance imaging (MRI) using Gd-EOB-DTPA in relation to various liver function tests in patients with liver disorders. Fifty-one patients with liver disease underwent Gd-EOB-DTPA-enhanced liver MRI. Based on region-of-interest (ROI) analysis, liver signal intensity was calculated using the spleen as reference tissue. Liver-spleen contrast ratio (LSCR) and relative liver enhancement (RLE) were calculated. Serum levels of total bilirubin, gamma glutamyl transpeptidase (GGT), aspartate aminotransferase (AST), alanine aminotransferase (ALT), glutamate dehydrogenase (GLDH), lactate dehydrogenase (LDH), serum albumin level (AL), prothrombin time (PT), creatinine (CR) as well as international normalised ratio (INR) and model for end-stage liver disease (MELD) score were tested for correlation with LSCR and RLE. Pre-contrast LSCR values correlated with total bilirubin (r = -0.39; p = 0.005), GGT (r = -0.37; p = 0.009), AST (r = -0.38; p = 0.013), ALT (r = -0.29; p = 0.046), PT (r = 0.52; p < 0.001), GLDH (r = -0.55; p = 0.044), INR (r = -0.42; p = 0.003), and MELD Score (r = -0.53; p < 0.001). After administration of Gd-EOB-DTPA bilirubin (r = -0.45; p = 0.001), GGT (r = -0.40; p = 0.004), PT (r = 0.54; p < 0.001), AST (r = -0.46; p = 0.002), ALT (r = -0.31; p = 0.030), INR (r = -0.45; p = 0.001) and MELD Score (r = -0.56; p < 0.001) significantly correlated with LSCR. RLE correlated with bilirubin (r = -0.40; p = 0.004), AST (r = -0.38; p = 0.013), PT (r = 0.42; p = 0.003), GGT (r = -0.33; p = 0.020), INR (r = -0.36; p = 0.011) and MELD Score (r = -0.43; p = 0.003). Liver-spleen contrast ratio and relative liver enhancement using Gd-EOB-DTPA correlate with a number of routinely used biochemical liver function tests, suggesting that hepatobiliary MRI may serve as a valuable biomarker for liver function. The strongest correlation with liver enhancement was found for the MELD Score. (orig.)

  15. Physisorption kinetics

    CERN Document Server

    Kreuzer, Hans Jürgen

    1986-01-01

    This monograph deals with the kinetics of adsorption and desorption of molecules physisorbed on solid surfaces. Although frequent and detailed reference is made to experiment, it is mainly concerned with the theory of the subject. In this, we have attempted to present a unified picture based on the master equation approach. Physisorption kinetics is by no means a closed and mature subject; rather, in writing this monograph we intended to survey a field very much in flux, to assess its achievements so far, and to give a reasonable basis from which further developments can take off. For this reason we have included many papers in the bibliography that are not referred to in the text but are of relevance to physisorption. To keep this monograph to a reasonable size, and also to allow for some unity in the presentation of the material, we had to omit a number of topics related to physisorption kinetics. We have not covered to any extent the equilibrium properties of physisorbed layers such as structures, phase tr...

  16. A Prototype Educational Model for Hepatobiliary Interventions: Unveiling the Role of Graphic Designers in Medical 3D Printing.

    Science.gov (United States)

    Javan, Ramin; Zeman, Merissa N

    2018-02-01

    In the context of medical three-dimensional (3D) printing, in addition to 3D reconstruction from cross-sectional imaging, graphic design plays a role in developing and/or enhancing 3D-printed models. A custom prototype modular 3D model of the liver was graphically designed depicting segmental anatomy of the parenchyma containing color-coded hepatic vasculature and biliary tree. Subsequently, 3D printing was performed using transparent resin for the surface of the liver and polyamide material to develop hollow internal structures that allow for passage of catheters and wires. A number of concepts were incorporated into the model. A representative mass with surrounding feeding arterial supply was embedded to demonstrate tumor embolization. A straight narrow hollow tract connecting the mass to the surface of the liver, displaying the path of a biopsy device's needle, and the concept of needle "throw" length was designed. A connection between the middle hepatic and right portal veins was created to demonstrate transjugular intrahepatic portosystemic shunt (TIPS) placement. A hollow amorphous structure representing an abscess was created to allow the demonstration of drainage catheter placement with the formation of pigtail tip. Percutaneous biliary drain and cholecystostomy tube placement were also represented. The skills of graphic designers may be utilized in creating highly customized 3D-printed models. A model was developed for the demonstration and simulation of multiple hepatobiliary interventions, for training purposes, patient counseling and consenting, and as a prototype for future development of a functioning interventional phantom.

  17. Epidemiology and risk factors associated with surgical site infection after different types of hepatobiliary and pancreatic surgery.

    Science.gov (United States)

    Morikane, Keita

    2017-10-01

    Surgical site infection (SSI) is one of the most common healthcare-associated infections (HAIs); however, SSI after hepatobiliary and pancreatic surgery (HBPS) has not been well investigated in a large cohort of patients. This study analyzed the factors associated with SSI following HBPS in Japan, using a Japanese national database. Data on HBPS performed between 2012 and 2014 were extracted from a national monitoring system for HAI: The Japan Nosocomial Infections Surveillance. Using multivariate logistic regression, I assessed the factors associated with SSI. The cumulative incidence of SSI following HBPS was 15.6% (2873/18,398). The incidence of SSI after pancreatoduodenectomy was 28.0%, which was significantly higher than that after liver resection and other types of HBPS (8.8 and 15.5%, respectively). Among the four traditional risk factors, the American Society of Anesthesiologists score was ineffective for predicting SSI in the final model of all three types of surgery. Additional risk factors were identified, including age and male gender. The incidence of and factors associated with SSI after the three types of HBPS analyzed differed significantly. To accurately compare hospital performance in relation to SSI following HBPS, the operative procedure category in the surveillance system must be divided into three types.

  18. From Clinical Standards to Translating Next-Generation Sequencing Research into Patient Care Improvement for Hepatobiliary and Pancreatic Cancers.

    Science.gov (United States)

    Kyrochristos, Ioannis D; Glantzounis, Georgios K; Ziogas, Demosthenes E; Gizas, Ioannis; Schizas, Dimitrios; Lykoudis, Efstathios G; Felekouras, Evangelos; Machairas, Anastasios; Katsios, Christos; Liakakos, Theodoros; Cho, William C; Roukos, Dimitrios H

    2017-01-18

    Hepatobiliary and pancreatic (HBP) cancers are associated with high cancer-related death rates. Surgery aiming for complete tumor resection (R0) remains the cornerstone of the treatment for HBP cancers. The current progress in the adjuvant treatment is quite slow, with gemcitabine chemotherapy available only for pancreatic ductal adenocarcinoma (PDA). In the advanced and metastatic setting, only two targeted drugs have been approved by the Food & Drug Administration (FDA), which are sorafenib for hepatocellular carcinoma and erlotinib for PDA. It is a pity that multiple Phase III randomized control trials testing the efficacy of targeted agents have negative results. Failure in the development of effective drugs probably reflects the poor understanding of genome-wide alterations and molecular mechanisms orchestrating therapeutic resistance and recurrence. In the post-ENCODE (Encyclopedia of DNA Elements) era, cancer is referred to as a highly heterogeneous and systemic disease of the genome. The unprecedented potential of next-generation sequencing (NGS) technologies to accurately identify genetic and genomic variations has attracted major research and clinical interest. The applications of NGS include targeted NGS with potential clinical implications, while whole-exome and whole-genome sequencing focus on the discovery of both novel cancer driver genes and therapeutic targets. These advances dictate new designs for clinical trials to validate biomarkers and drugs. This review discusses the findings of available NGS studies on HBP cancers and the limitations of genome sequencing analysis to translate genome-based biomarkers and drugs into patient care in the clinic.

  19. From Clinical Standards to Translating Next-Generation Sequencing Research into Patient Care Improvement for Hepatobiliary and Pancreatic Cancers

    Directory of Open Access Journals (Sweden)

    Ioannis D. Kyrochristos

    2017-01-01

    Full Text Available Hepatobiliary and pancreatic (HBP cancers are associated with high cancer-related death rates. Surgery aiming for complete tumor resection (R0 remains the cornerstone of the treatment for HBP cancers. The current progress in the adjuvant treatment is quite slow, with gemcitabine chemotherapy available only for pancreatic ductal adenocarcinoma (PDA. In the advanced and metastatic setting, only two targeted drugs have been approved by the Food & Drug Administration (FDA, which are sorafenib for hepatocellular carcinoma and erlotinib for PDA. It is a pity that multiple Phase III randomized control trials testing the efficacy of targeted agents have negative results. Failure in the development of effective drugs probably reflects the poor understanding of genome-wide alterations and molecular mechanisms orchestrating therapeutic resistance and recurrence. In the post-ENCODE (Encyclopedia of DNA Elements era, cancer is referred to as a highly heterogeneous and systemic disease of the genome. The unprecedented potential of next-generation sequencing (NGS technologies to accurately identify genetic and genomic variations has attracted major research and clinical interest. The applications of NGS include targeted NGS with potential clinical implications, while whole-exome and whole-genome sequencing focus on the discovery of both novel cancer driver genes and therapeutic targets. These advances dictate new designs for clinical trials to validate biomarkers and drugs. This review discusses the findings of available NGS studies on HBP cancers and the limitations of genome sequencing analysis to translate genome-based biomarkers and drugs into patient care in the clinic.

  20. Hyperintense HCC on hepatobiliary phase images of gadoxetic acid-enhanced MRI: Correlation with clinical and pathological features

    International Nuclear Information System (INIS)

    Kim, Ja Young; Kim, Myeong-Jin; Kim, Kyung Ah; Jeong, Hyeon Tae; Park, Young Nyun

    2012-01-01

    Purpose: To retrospectively determine whether the hyperintense hepatocellular carcinomas (HCCs) seen on the hepatobiliary phase of gadoxetic acid-enhanced MR imaging (EOB-MRI) might have different histologic characteristics from usual hypointense HCCs. Materials and methods: Two hundred three surgically proven HCCs from 192 patients who underwent preoperative EOB-MRI were analyzed. The demographic and histologic characteristics of hyperintense HCCs were compared with usual hypointense HCCs by using the t-test or Fisher's exact test. Results: By visual assessment, 18 (8.8%) tumors were classified as hyperintense HCCs. Patients with hyperintense HCC were significantly (p < 0.05) older (60.1 vs. 55.2 years) than those with hypointense HCCs. Hyperintense HCCs showed significantly lower rate of microvascular invasion (27.8% vs. 53.5%) and significantly higher rate of peliosis (61.1% vs. 30.8%). Hyperintense HCCs were more frequently expanding type, and none showed infiltrative type or scirrhous histologic pattern. Conclusions: Hyperintense HCCs seem to have clinical and histologic features that might be related with more favorable outcomes.

  1. Application of pharmacokinetic modeling to the radiation dosimetry of hepatobiliary agents

    International Nuclear Information System (INIS)

    Loberg, M.D.; Buddemeyer, E.U.

    1981-01-01

    Dosimetry calculations based on biodistribution data from lower animal species often inadequately approximate the true dosimetry in humans and seldom apply in the presence of human pathology. An alternative approach is to use animal data for the limited purpose of developing a pharmacokinetic model describing the various compartments and their interconnecting pathways. To the extent that components are similarly connected in man, the model can be used to compute cumulative concentrations (μCi-h/gm) in humans by using the compartment masses and rate constants appropriate for man. In this manner dose estimates can be obtained which are less dependent upon the species from which the model was derived. The altered radiation dose in certain disease states having a known relationship to the model can also be predicted with confidence. This work reports the development in dogs of a four-compartment model which accurately describes the in-vivo distribution of Tc/sup 99m/-HIDA. The pharmacokinetic model was used to predict the kinetics of the HIDA analog which would yield clinically useful information, while minimizing patient radiation exposure

  2. Stochastic kinetics

    International Nuclear Information System (INIS)

    Colombino, A.; Mosiello, R.; Norelli, F.; Jorio, V.M.; Pacilio, N.

    1975-01-01

    A nuclear system kinetics is formulated according to a stochastic approach. The detailed probability balance equations are written for the probability of finding the mixed population of neutrons and detected neutrons, i.e. detectrons, at a given level for a given instant of time. Equations are integrated in search of a probability profile: a series of cases is analyzed through a progressive criterium. It tends to take into account an increasing number of physical processes within the chosen model. The most important contribution is that solutions interpret analytically experimental conditions of equilibrium (moise analysis) and non equilibrium (pulsed neutron measurements, source drop technique, start up procedures)

  3. Augmented reality technology for preoperative planning and intraoperative navigation during hepatobiliary surgery: A review of current methods.

    Science.gov (United States)

    Tang, Rui; Ma, Long-Fei; Rong, Zhi-Xia; Li, Mo-Dan; Zeng, Jian-Ping; Wang, Xue-Dong; Liao, Hong-En; Dong, Jia-Hong

    2018-02-19

    Augmented reality (AR) technology is used to reconstruct three-dimensional (3D) images of hepatic and biliary structures from computed tomography and magnetic resonance imaging data, and to superimpose the virtual images onto a view of the surgical field. In liver surgery, these superimposed virtual images help the surgeon to visualize intrahepatic structures and therefore, to operate precisely and to improve clinical outcomes. The keywords "augmented reality", "liver", "laparoscopic" and "hepatectomy" were used for searching publications in the PubMed database. The primary source of literatures was from peer-reviewed journals up to December 2016. Additional articles were identified by manual search of references found in the key articles. In general, AR technology mainly includes 3D reconstruction, display, registration as well as tracking techniques and has recently been adopted gradually for liver surgeries including laparoscopy and laparotomy with video-based AR assisted laparoscopic resection as the main technical application. By applying AR technology, blood vessels and tumor structures in the liver can be displayed during surgery, which permits precise navigation during complex surgical procedures. Liver transformation and registration errors during surgery were the main factors that limit the application of AR technology. With recent advances, AR technologies have the potential to improve hepatobiliary surgical procedures. However, additional clinical studies will be required to evaluate AR as a tool for reducing postoperative morbidity and mortality and for the improvement of long-term clinical outcomes. Future research is needed in the fusion of multiple imaging modalities, improving biomechanical liver modeling, and enhancing image data processing and tracking technologies to increase the accuracy of current AR methods. Copyright © 2018 First Affiliated Hospital, Zhejiang University School of Medicine in China. Published by Elsevier B.V. All rights

  4. The enhanced value of combining conventional and 'omics' analyses in early assessment of drug-induced hepatobiliary injury

    International Nuclear Information System (INIS)

    Ellinger-Ziegelbauer, Heidrun; Adler, Melanie; Amberg, Alexander; Brandenburg, Arnd; Callanan, John J.; Connor, Susan; Fountoulakis, Michael; Gmuender, Hans; Gruhler, Albrecht; Hewitt, Philip; Hodson, Mark; Matheis, Katja A.; McCarthy, Diane; Raschke, Marian; Riefke, Bjoern; Schmitt, Christina S.; Sieber, Max; Sposny, Alexandra; Suter, Laura; Sweatman, Brian

    2011-01-01

    The InnoMed PredTox consortium was formed to evaluate whether conventional preclinical safety assessment can be significantly enhanced by incorporation of molecular profiling ('omics') technologies. In short-term toxicological studies in rats, transcriptomics, proteomics and metabolomics data were collected and analyzed in relation to routine clinical chemistry and histopathology. Four of the sixteen hepato- and/or nephrotoxicants given to rats for 1, 3, or 14 days at two dose levels induced similar histopathological effects. These were characterized by bile duct necrosis and hyperplasia and/or increased bilirubin and cholestasis, in addition to hepatocyte necrosis and regeneration, hepatocyte hypertrophy, and hepatic inflammation. Combined analysis of liver transcriptomics data from these studies revealed common gene expression changes which allowed the development of a potential sequence of events on a mechanistic level in accordance with classical endpoint observations. This included genes implicated in early stress responses, regenerative processes, inflammation with inflammatory cell immigration, fibrotic processes, and cholestasis encompassing deregulation of certain membrane transporters. Furthermore, a preliminary classification analysis using transcriptomics data suggested that prediction of cholestasis may be possible based on gene expression changes seen at earlier time-points. Targeted bile acid analysis, based on LC-MS metabonomics data demonstrating increased levels of conjugated or unconjugated bile acids in response to individual compounds, did not provide earlier detection of toxicity as compared to conventional parameters, but may allow distinction of different types of hepatobiliary toxicity. Overall, liver transcriptomics data delivered mechanistic and molecular details in addition to the classical endpoint observations which were further enhanced by targeted bile acid analysis using LC/MS metabonomics.

  5. Role of Hepatobiliary Scintigraphy and Preoperative Liver Biopsy for Exclusion of Biliary Atresia in Neonatal Cholestasis Syndrome.

    Science.gov (United States)

    Mandelia, Ankur; Lal, Richa; Mutt, Nijagal

    2017-09-01

    All diagnostic algorithms for Neonatal Cholestasis Syndrome (NCS) focus on differentiating numerous medical causes from Biliary Atresia (BA). No preoperative diagnostic algorithm has 100% diagnostic accuracy for BA and yet, timely diagnosis is crucial to optimize surgical outcome. Markers for high index of clinical suspicion for BA are: a "usually" well thriving infant with conjugated hyperbilirubinemia, raised gamma glutamyl transpeptidase, persistently "acholic" stools, firm hepatomegaly with dysmorphic, hypoplastic gall bladder. In the presence of above 'red flag' signs, there has been much debate on diagnostic accuracy of percutaneous liver biopsy (PLB) vs. hepatobiliary scintigraphy (HBS) to substantiate or exclude BA. Recent guidelines suggest a shift towards PLB (91.6% overall diagnostic accuracy) as the diagnostic cornerstone with key differentiating feature being 'bile ductular proliferation'. HBS has a high (98.7%) sensitivity but low specificity (37-74%) with an overall diagnostic accuracy of 67% for BA. Severe hepatocellular disease without anatomic obstruction would also have a non-excretory scan. Thus, while excretory HBS excludes BA, non-excretion does not confirm BA. Hence, diagnostic algorithms relying on non-excretory HBS as the primary standalone benchmark for surgical exploration would be mired by a high negative laparotomy rate revealing a normal peroperative cholangiogram (POC). However, an excretory HBS obviates need for laparotomy in case of equivocal stool color or PLB. A POC continues to be the ultimate gold standard. Hence, with high index of clinical suspicion but equivocal ultrasonography or PLB and a non-excretory HBS, the baby should not be denied a POC within time frame crucial for successful hepatoportoenterostomy.

  6. Kinetic buffers.

    Science.gov (United States)

    Alibrandi, Giuseppe; Fabbrizzi, Luigi; Licchelli, Maurizio; Puglisi, Antonio

    2015-01-12

    This paper proposes a new type of molecular device that is able to act as an inverse proton sponge to slowly decrease the pH inside a reaction vessel. This makes the automatic monitoring of the concentration of pH-sensitive systems possible. The device is a composite formed of an alkyl chloride, which kinetically produces acidity, and a buffer that thermodynamically modulates the variation in pH value. Profiles of pH versus time (pH-t plots) have been generated under various experimental conditions by computer simulation, and the device has been tested by carrying out automatic spectrophotometric titrations, without using an autoburette. To underline the wide variety of possible applications, this new system has been used to realize and monitor HCl uptake by a di-copper(II) bistren complex in a single run, in a completely automatic experiment. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. Hepatobiliary scintigraphy in the assessment of long-term complication after biliary-enteric anastomosis: role in the diagnosis of post-operative segmental or total biliary obstruction

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jae Seung; Moon, Dae Hyuk; Lee, Sung Gyu; Lee, Yung Joo; Park, Kwang Min; Shin, Jung Woo; Ryu, Jin Sook; Lee, Hee Kyung [Asan Medicial Center, Seoul (Korea, Republic of)

    1998-07-01

    The purpose of this study was to investigate the accuracy of hepatobiliary scintigraphy (HBS) in the diagnosis of segmental or total biliary obstruction during long-term follow-up period after curative radical surgery with biliary-enteric anastomosis. The study population included 80 patients who underwent biliary-enteric anastomoses for benign (n=33) or malignant (n=47) biliary disease. Fifty-six of these 80 patients also underwent curative hepatic resection. Ninety eight hepatobiliary scintigrams using {sup 99m}Tc-DISIDA were performed at least 1 month after surgery (median 9 month). The scintigraphic criteria of total biliary obstruction we used were intestinal excretion beyond one hour or delayed hepatobiliary washout despite the presence of intestinal excretion. Segmental biliary obstruction was defined as delayed segmental excretion. The accuracy for biliary obstruction was evaluated according to different clinical situations. There were 9 instances with total biliary obstruction and 23 with segmental bile duct obstruction. Diagnosis of biliary obstruction was confirmed by percutaneous transhepatic cholangiography or surgery in 13, and follow-up clinical data for at least 6 months in 19 instances. Among the 32 instances with biliary symptoms and abnormal liver function, HBS allowed correct diagnosis in all 32(9 total, 14 segmental obstruction and 9 non-obstruction). Of the 40 with nonspecific symptom or isolated elevation of serum alkaline phosphatase, HBS diagnosed 8 of the 9 segmental biliary obstruction and 30 of the 31 non-obstruction. There were no biliary obstruction and no false positive result of scintigraphy in 26 instances which had no clinical symptom or signs of biliary obstruction. Diagnostic sensitivity of HBS was 100% (9/9) for total biliary obstruction, and 96%(22/23) for segmental bile obstruction. Specificity was 98%(39/40) in patients who had abnormal symptom or sign. Hepatobiliary scintigraphy is a highly accurate modality in the

  8. Hepatobiliary scintigraphy in the assessment of long-term complication after biliary-enteric anastomosis: role in the diagnosis of post-operative segmental or total biliary obstruction

    International Nuclear Information System (INIS)

    Kim, Jae Seung; Moon, Dae Hyuk; Lee, Sung Gyu; Lee, Yung Joo; Park, Kwang Min; Shin, Jung Woo; Ryu, Jin Sook; Lee, Hee Kyung

    1998-01-01

    The purpose of this study was to investigate the accuracy of hepatobiliary scintigraphy (HBS) in the diagnosis of segmental or total biliary obstruction during long-term follow-up period after curative radical surgery with biliary-enteric anastomosis. The study population included 80 patients who underwent biliary-enteric anastomoses for benign (n=33) or malignant (n=47) biliary disease. Fifty-six of these 80 patients also underwent curative hepatic resection. Ninety eight hepatobiliary scintigrams using 99m Tc-DISIDA were performed at least 1 month after surgery (median 9 month). The scintigraphic criteria of total biliary obstruction we used were intestinal excretion beyond one hour or delayed hepatobiliary washout despite the presence of intestinal excretion. Segmental biliary obstruction was defined as delayed segmental excretion. The accuracy for biliary obstruction was evaluated according to different clinical situations. There were 9 instances with total biliary obstruction and 23 with segmental bile duct obstruction. Diagnosis of biliary obstruction was confirmed by percutaneous transhepatic cholangiography or surgery in 13, and follow-up clinical data for at least 6 months in 19 instances. Among the 32 instances with biliary symptoms and abnormal liver function, HBS allowed correct diagnosis in all 32(9 total, 14 segmental obstruction and 9 non-obstruction). Of the 40 with nonspecific symptom or isolated elevation of serum alkaline phosphatase, HBS diagnosed 8 of the 9 segmental biliary obstruction and 30 of the 31 non-obstruction. There were no biliary obstruction and no false positive result of scintigraphy in 26 instances which had no clinical symptom or signs of biliary obstruction. Diagnostic sensitivity of HBS was 100% (9/9) for total biliary obstruction, and 96%(22/23) for segmental bile obstruction. Specificity was 98%(39/40) in patients who had abnormal symptom or sign. Hepatobiliary scintigraphy is a highly accurate modality in the evaluation of

  9. Transport mechanisms of hepatic uptake and bile excretion in clinical hepatobiliary scintigraphy with 99mTc-N-pyridoxyl-5-methyltryptophan

    International Nuclear Information System (INIS)

    Kobayashi, Masato; Nakanishi, Takeo; Nishi, Kodai; Higaki, Yusuke; Okudaira, Hiroyuki; Ono, Masahiro; Tsujiuchi, Takafumi; Mizutani, Asuka; Nishii, Ryuichi; Tamai, Ikumi; Arano, Yasushi; Kawai, Keiichi

    2014-01-01

    Introduction: In clinical hepatobiliary scintigraphy, 99m Tc-N-pyridoxyl-5-methyltryptophan ( 99m Tc-PMT) is an effective radiotracer among the 99m Tc-pyridoxylaminates. However, the mechanisms of human hepatic uptake and bile excretion transport of 99m Tc-PMT have not been determined. We thus investigated the transport mechanisms of human hepatic uptake and bile excretion in hepatobiliary scintigraphy with 99m Tc-PMT. Methods: Four solute carrier (SLC) transporters involved in hepatic uptake were evaluated using human embryonic kidney (HEK) and HeLa cells with high expression of SLC transporters (organic anion transporting polypeptide (OATP)1B1, OATP1B3, OATP2B1, organic anion transporters (OAT)2 and organic cation transporters (OCT)1) after 5 min of 99m Tc-PMT incubation. Metabolic analysis of 99m Tc-PMT was performed using pooled human liver S9. Adenosine triphosphate (ATP)-binding cassette (ABC) transporters for bile excretion were examined using hepatic ABC transporter vesicles human expressing multiple drug resistance 1 (MDR1), multidrug resistance-associated protein 2 (MRP2), breast cancer resistance protein or bile salt export pump. 99m Tc-PMT was incubated for 1, 3 and 5 min with ATP or adenosine monophosphate and these vesicles. SPECT scans were performed in normal and Eisai hyperbilirubinemic (EHBR) model rats, deficient in Mrp2 transporters, without and with verapamil (rat Mdr1 and human MDR1 inhibitor) after intravenous injection of 99m Tc-PMT. Results: Uptake of 99m Tc-PMT in HEK293/OATP1B1 and HeLa/OATP1B3 was significantly higher than that in HEK293- and HeLa-mock cells. 99m Tc-PMT was not metabolized in the human liver S9. In vesicles with high expression of ABC transporters, uptake of MDR1 or MRP2 was significantly higher at all incubation times. Bile excretion of 99m Tc-PMT was also identified by comparison between normal and EHBR rats with and without verapamil on in-vivo imaging. Conclusions: Human hepatic uptake of 99m Tc-PMT was transferred

  10. The Phantom Menace for Patients with Hepatobiliary Diseases: Shewanella haliotis, Often Misidentified as Shewanella algae in Biochemical Tests and MALDI-TOF Analysis.

    Science.gov (United States)

    Byun, Jung-Hyun; Park, Hyunwoong; Kim, Sunjoo

    2017-03-24

    Although Shewanella algae has been known to have weak pathogenicity, case reports on infections with this species have been steadily increasing. S. algae and S. haliotis are difficult to distinguish from each other with conventional phenotypic methods. We reviewed the microbiological and clinical features of S. algae and S. haliotis infections at our institute. Bacterial culture and identification reports from patient samples from 2010 to 2014 were reviewed to screen the cases of Shewanella infections. In addition to conventional biochemical tests, 16S rRNA gene sequence analysis and matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry were performed for 19 stored bacterial isolates. Medical records were reviewed for clinical characteristics and laboratory findings. All isolates were identified as S. algae by using VITEK 2. MALDI-TOF also identified all isolates as S. algae with a 99.9 confidence value. In contrast, 16S rRNA analysis identified 10 isolates as S. algae and 9 isolates as S. haliotis. Both S. algae (60%) and S. haliotis (77%) infections were strongly associated with diseases of the hepatobiliary tract and pancreas. To distinguish between S. algae and S. haliotis, 16S rRNA gene sequence analysis seems more accurate than biochemical tests or MALDI-TOF. Patients with underlying diseases in the hepatobiliary tract and pancreas seem to be susceptible to these marine pathogens.

  11. Evaluation of results of the prostigmine-morphine test with quantitative hepatobiliary scintigraphy: a new method for the diagnosis of sphincter of Oddi dyskinesia

    International Nuclear Information System (INIS)

    Madacsy, L.; Veloesy, B.; Lonovics, J.; Csernay, L.

    1995-01-01

    We have visualized SO spasms during prostigmine-morphine provocation by means of quantitative hepatobiliary scintigraphy (QHBS). Twenty-two cholecystectomized patients with typical postprandial biliary pain were included in this study. In the first series of studies, QHBS with technetium-99m 2,6-diethylphenylcarbamoylmethyl-diacetic acid was performed in each patient 2 days before prostigmine-morphine provocation. The time to peak activity and the half-time of excretion over the liver parenchyma, hepatic hilum and common bile duct, and the duodenum appearance time, were determined and served as control values. In the second series of experiments, sphincter spasms were evoked by prostigmine-morphine administration and visualized by means of QHBS. The same parameters were evaluated and serum levels of aspartate aminotransferase (AST) were determined simultaneously at regular intervals. In 12 patients who responded to prostigmine-morphine provocation with typical biliary pain and a significant AST elevation (Nardi positive group) the hepatobiliary scintigram demonstrated a marked biliary obstruction. Four of the remaining ten patients indicated atypical abdominal pain during prostigmine-morphine provocation, but the AST level remained unchanged in all ten (Nardi negative group). In this group, QHBS revealed a slower, but free transpapillary flow of the tracer. QHBS combined with the prostigmine-morphine provocation test proved to be a useful non-invasive method for the detection of pathological sphincter spasms in patients with SO dyskinesia. (orig./MG)

  12. Preparation of N-(3-BROMO-2,4,6-trimethylacetanilide) iminodiacetic acid and its 99MTc-complex for hepatobiliary imaging

    International Nuclear Information System (INIS)

    Choi, Ok Ja; Hong, Young Don; Gwon, Hui Jeong; Choi, Sang Mu; Choi, Sun Ju

    2005-01-01

    N-(3-bromo-2,4,6-trimethylacetanilide) iminodiacetic acid (BrTIDA) was synthesized using nitrilotriacetic anhydride prepared in situ, and lyophilized vials were prepared which contained 20 mg of BrTIDA and 0.4 mg of SnCl 2 . To evaluate the clinical efficacy of the in-house prepared lyophilized kit, a technetium-99m complex of BrTIDA was prepared; its in vivo pharmacokinetic behavior was evaluated via animal studies to assess the hepatocytic function and the functional status of the cystic duct and the gallbladder. Serial static image scans of rabbits and the biodistribution in mice injected with 99m Tc-BrTIDA revealed that none of the tissues except for the hepatobiliary system showed radioactivity concentrations, and a rapid clearance from the organs was observed. In conclusion, a lyophilized kit and its prepared 99m Tc-BrTIDA can be applied as a hepatobiliary imaging agent for the evaluation of the functional status of the hepatocytes and the patency of the biliary duct

  13. Technetium-99m-labeled N-(2,6-dimethylphenylcarbamoylmethyl) iminodiacetic acid (/sup 99m/Tc HIDA): a new radiopharmaceutical for hepatobiliary imaging studies

    International Nuclear Information System (INIS)

    Ryan, J.; Cooper, M.; Loberg, M.; Harvey, E.; Sikorski, S.

    1977-01-01

    An easily formulated, stable kit preparation of technetium-99m HIDA, suitable for use in humans, was developed and tested in mice and dogs. The tracer was cleared rapidly from the blood and excreted predominantly by the liver in both species. In dogs, the hepatobiliary clearance of Tc-99m HIDA was significantly greater than that of C-14 HIDA and Sn-113 HIDA. The LD 50 for HIDA in mice, 168 mg/kg, exceeded the average human dose by a factor of 1000 on a per-weight basis. Blood clearance curves for Tc-99m HIDA in 12 normal subjects were biexponential with half-times of 4.6 +- 1.0 min and 31.5 +- 7.0 min, and cumulative 90-min urine samples contained 14.2 +- 1.8% of the injected dose. Images in normal subjects and nonjaundiced patients showed rapid concentration of tracer by the liver and activity was present within the biliary system in 10 to 20 min. In jaundiced patients, the tracer blood clearance was delayed and urinary excretion increased, but intestinal activity, indicating biliary patency, was imaged in those patients without complete focal obstruction of the common duct. Technetium-99m HIDA is a nontoxic radiopharmaceutical useful for clinical evaluation of hepatobiliary disorders in humans

  14. Synthesis of 2,6-diisopropyl-phenylcarbamoylmethyl-iminodiacetic acid (DISIDA) and 4-n-p-butyl-phenylcarbamoylmethyl-iminodiacetic acid (BUTYL-IDA). Preparation of lyophilized kit to be used as 99(supm)Tc agent in hepatobiliary system

    International Nuclear Information System (INIS)

    Hamada, E.S.; Barbosa, M.F. de; Theodora, M.A.; Almeida, M. de; Colturato, M.T.; Muramoto, E.; Silva, C.P.G. da.

    1987-08-01

    The synthesis of 2,6 diisopropyl IDA (DISIDA) and 4-n-butyl IDA (BUTIL-IDA) is described. Their spectroscopic properties, radiopharmaceutical preparation and their use as 99 (sup m)Tc complex agent in hepatobiliary studies, are also reported. (Author) [pt

  15. Evaluation of the endothelin receptor antagonists ambrisentan, bosentan, macitentan, and sitaxsentan as hepatobiliary transporter inhibitors and substrates in sandwich-cultured human hepatocytes.

    Directory of Open Access Journals (Sweden)

    Eve-Irene Lepist

    Full Text Available Inhibition of the transporter-mediated hepatobiliary elimination of bile salts is a putative mechanism for liver toxicity observed with some endothelin receptor antagonists (ERAs.Sandwich-cultured human hepatocytes were used to study the hepatobiliary distribution and accumulation of exogenous taurocholate, ERAs and endogenous bile acids. The molecular mechanisms for findings in hepatocytes or clinical observations were further explored using either vesicular assays (efflux transporters or transfected cell-lines (uptake transporters. Inhibition constants (IC50 were measured for the human hepatobiliary transporters bile salt export pump (BSEP, sodium taurocholate cotransporting polypeptide (NTCP, multidrug resistance protein 2 (MRP2, P-glycoprotein (Pgp, breast cancer resistance protein (BCRP, organic anion-transporting polypeptide 1B1 (OATP1B1 and OATP1B3.The ERAs showed dose-dependent reductions in exogenous taurocholate cellular accumulation in human hepatocytes, with macitentan having the greatest effect. Consistent with their effects on bile acids, the ERAs inhibited bile transporters. IC50 values for OATP1B1 and OATP1B3 ranged from 2 µM for macitentan to 47 µM for ambrisentan. Macitentan and bosentan also inhibited NTCP with IC50 values of 10 and 36 µM, respectively. Similar to previously reported findings with sitaxsentan, BSEP inhibition was observed for bosentan and macitentan with IC50 values of 42 and 12 µM, respectively. In contrast, ambrisentan showed little or no inhibition of these transporters. Other transporters tested were weakly inhibited by the ERAs. Accumulation in hepatocytes was also a factor in the effects on bile transport. Macitentan demonstrated the greatest accumulation in human hepatocytes (∼100x followed by sitaxsentan (∼40x, bosentan (∼20x and ambrisentan (∼2x.Significant differences in the inhibition of hepatic transporters were observed between the evaluated ERAs in vitro. Macitentan had the highest

  16. The role of surgical clips in the evaluation of interfractional uncertainty for treatment of hepatobiliary and pancreatic cancer with postoperative radiotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Bae, Jin Suk; Kim, Dong Hyun; Kim, Won Taek; Kim, Yong Ho; Park, Dahl; Ki, Yong Kan [Pusan National University Hospital, Pusan National University School of Medicine, Busan (Korea, Republic of)

    2017-03-15

    To evaluate the utility of implanted surgical clips for detecting interfractional errors in the treatment of hepatobiliary and pancreatic cancer with postoperative radiotherapy (PORT). Twenty patients had been treated with PORT for locally advanced hepatobiliary or pancreatic cancer, from November 2014 to April 2016. Patients underwent computed tomography simulation and were treated in expiratory breathing phase. During treatment, orthogonal kilovoltage (kV) imaging was taken twice a week, and isocenter shifts were made to match bony anatomy. The difference in position of clips between kV images and digitally reconstructed radiographs was determined. Clips were consist of 3 proximal clips (clip{sub p}, ≤2 cm) and 3 distal clips (clip{sub d}, >2 cm), which were classified according to distance from treatment center. The interfractional displacements of clips were measured in the superior-inferior (SI), anterior-posterior (AP), and right-left (RL) directions. The translocation of clip was well correlated with diaphragm movement in 90.4% (190/210) of all images. The clip position errors greater than 5 mm were observed in 26.0% in SI, 1.8% in AP, and 5.4% in RL directions, respectively. Moreover, the clip position errors greater than 10 mm were observed in 1.9% in SI, 0.2% in AP, and 0.2% in RL directions, despite respiratory control. Quantitative analysis of surgical clip displacement reflect respiratory motion, setup errors and postoperative change of intraabdominal organ position. Furthermore, position of clips is distinguished easily in verification images. The identification of the surgical clip position may lead to a significant improvement in the accuracy of upper abdominal radiation therapy.

  17. Prognosis of small hepatocellular nodules detected only at the hepatobiliary phase of Gd-EOB-DTPA-enhanced MR imaging as hypointensity in cirrhosis or chronic hepatitis

    Energy Technology Data Exchange (ETDEWEB)

    Higaki, Atsushi; Ito, Katsuyoshi; Tamada, Tsutomu; Sone, Teruki; Kanki, Akihiko; Noda, Yasufumi; Yasokawa, Kazuya; Yamamoto, Akira [Kawasaki Medical School, Department of Radiology, Kurashiki City, Okayama (Japan)

    2014-10-15

    To evaluate the prognosis of ''strict'' high-risk nodules (small hepatocellular nodules detected only in the hepatobiliary phase of initial Gd-EOB-DTPA-enhanced MR examination) in patients with cirrhosis or chronic hepatitis. The study included thirty-three patients with 60 ''strict'' high-risk nodules showing hypointensity at the hepatobiliary phase that was undetectable at the vascular phase and other conventional sequences of initial Gd-EOB-DTPA-enhanced MR imaging. These nodules were observed on follow-up MR examinations until hypervascularity was detected. The potential predictive factors for hypervascular transformation were compared between two groups (group A showing hypervascular transformation, group B not showing hypervascularization). Ten (16.7 %) of 60 ''strict'' high-risk nodules showed hypervascular transformation during follow-up periods (group A). The growth rates of the nodules in group A (6.3 ± 4.5 mm/year) were significantly higher than those in group B (3.4 ± 7.2 mm/year) (p = 0.003). Additionally, the median observation period in group A (177.5 ± 189.5 day) was significantly shorter than in group B (419 ± 372.2 day) (p = 0.045). The other predictive factors were not significantly correlated with hypervascularization. Subsets of ''strict'' high-risk nodules showed hypervascular transformation during follow-up periods in association with increased growth rates, indicating that nodule growth rate is an important predictive factor for hypervascularization. (orig.)

  18. Phantom and animal studies of a new hepatobiliary agent for MR imaging: comparison of Gd-DTPA-DeA with Gd-EOB-DTPA.

    Science.gov (United States)

    Yoshikawa, Kohki; Inoue, Yusuke; Akahane, Masaaki; Shimada, Morio; Itoh, Sayaka; Seno, Atsushi; Hayashi, Sanshin

    2003-08-01

    To investigate the characteristics of Gd-DTPA-DeA as a hepatobiliary contrast agent for MR imaging in comparison with those of Gd-EOB-DTPA. We undertook phantom experiments to assess T1 relaxivity for Gd-DTPA-DeA, Gd-EOB-DTPA, and Gd-DTPA in human plasma. For Gd-DTPA-DeA and Gd-EOB-DTPA, we evaluated the contrast effect in rats using an SPGR sequence. The contrast ratios of liver and abdominal aorta were measured up to 21 minutes after intravenous administration of the agents. Visualization of the bile duct and renal pelvis was also assessed. In human plasma, T1 relaxivity was similar for Gd-DTPA-DeA and Gd-EOB-DTPA, and higher than those for Gd-DTPA. Whereas the contrast ratio of liver peaked about five minutes after the injection of Gd-EOB-DTPA and was followed by a subsequent decline, a continuous rise was shown for Gd-DTPA-DeA, resulting in a larger maximal contrast effect. Contrast ratios of the abdominal aorta were larger for Gd-DTPA-DeA. Biliary excretion was observed for both agents but occurred earlier with Gd-EOB-DTPA. While renal excretion was shown for all rats three minutes after the injection of Gd-EOB-DTPA, it was not observed for Gd-DTPA-DeA. Gd-DTPA-DeA may be used as a hepatobiliary contrast agent and shows different pharmacokinetics from Gd-EOB-DTPA. Copyright 2003 Wiley-Liss, Inc.

  19. Correcting for respiratory motion in liver PET/MRI: preliminary evaluation of the utility of bellows and navigated hepatobiliary phase imaging

    Energy Technology Data Exchange (ETDEWEB)

    Hope, Thomas A. [Department of Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco, CA (United States); Department of Radiology, San Francisco VA Medical Center, San Francisco, CA (United States); Verdin, Emily F. [Department of Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco, CA (United States); Bergsland, Emily K. [Division of Hematology/Oncology, Department of Medicine, University of California, San Francisco, San Francisco, CA (United States); Ohliger, Michael A. [Department of Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco, CA (United States); Department of Radiology, San Francisco General Hospital, San Francisco, CA (United States); Corvera, Carlos University; Nakakura, Eric K. [Division of Surgical Oncology, Department of Surgery, University of California, San Francisco, San Francisco, CA (United States)

    2015-09-18

    The purpose of this study was to evaluate the utility of bellows-based respiratory compensation and navigated hepatobiliary phase imaging to correct for respiratory motion in the setting of dedicated liver PET/MRI. Institutional review board approval and informed consent were obtained. Six patients with metastatic neuroendocrine tumor were imaged using Ga-68 DOTA-TOC PET/MRI. Whole body imaging and a dedicated 15-min liver PET acquisition was performed, in addition to navigated and breath-held hepatobiliary phase (HBP) MRI. Liver PET data was reconstructed three ways: the entire data set (liver PET), gated using respiratory bellows (RC-liver PET), and a non-gated data set reconstructed using the same amount of data used in the RC-liver PET (shortened liver PET). Liver lesions were evaluated using SUV{sub max}, SUV{sub peak}, SUV{sub mean}, and Vol{sub isocontour}. Additionally, the displacement of each lesion between the RC-liver PET images and the navigated and breath-held HBP images was calculated. Respiratory compensation resulted in a 43 % increase in SUVs compared to ungated data (liver vs RC-liver PET SUV{sub max} 26.0 vs 37.3, p < 0.001) and a 25 % increase compared to a non-gated reconstruction using the same amount of data (RC-liver vs shortened liver PET SUV{sub max} 26.0 vs 32.6, p < 0.001). Lesion displacement was minimized using navigated HBP MRI (1.3 ± 1.0 mm) compared to breath-held HBP MRI (23.3 ± 1.0 mm). Respiratory bellows can provide accurate respiratory compensation when imaging liver lesions using PET/MRI, and results in increased SUVs due to a combination of increased image noise and reduced respiratory blurring. Additionally, navigated HBP MRI accurately aligns with respiratory compensated PET data.

  20. Methods of nonlinear kinetics

    OpenAIRE

    Gorban, A. N.; Karlin, I. V.

    2003-01-01

    Nonlinear kinetic equations are reviewed for a wide audience of specialists and postgraduate students in physics, mathematical physics, material science, chemical engineering and interdisciplinary research. Contents: The Boltzmann equation, Phenomenology and Quasi-chemical representation of the Boltzmann equation, Kinetic models, Discrete velocity models, Direct simulation, Lattice Gas and Lattice Boltzmann models, Minimal Boltzmann models for flows at low Knudsen number, Other kinetic equati...

  1. Diagnostic Significance of the Blood Disappearance Rate of 131I-Rose Bengal and of 198Au colloid in Hepatobiliary Diseases

    International Nuclear Information System (INIS)

    Chun, Young Kyoon; Hahn, Shim Suk; Koh, Chang Soon

    1971-01-01

    The liver function test was performed by means of two radioisotope tracer techniques in 20 normal subjects and in 63 patients with hepatobiliary diseases. The blood disappearance rates of 131 I-rose bengal and of 198 Au colloid were determined by external counting method. The hepatocellular function and the hepatic blood flow were estimated from the observed data and the results were compared with those of the conventional liver function tests. The results obtained were as follows: 1. The mean blood disappearance half time of 131 I-rose bengal was 6.6±0.63 minutes in normal control, 17.7±6.93 in cirrhosis of the liver, 16.6±4. 80 in acute hepatitis, and 14 7±3.46 in obstructive jaundice. It was markedly prolonged in the hepatobiliary diseases as compared with the normal control, but there was no significant difference among the hepatobiliary diseases. 2.The mean blood disappearance half time of 198 Au colloid was 4. 0±0. 66 minutes in normal control, 9.8±3.42 in cirrhosis of the liver, 4.4±0.82 in acute hepatitis, and 5.0±1.42 in obstructive jaundice. The difference between cirrhosis of the liver and normal control was statistically significant. However, there was no definite difference among acute hepatitis, obstructive jaundice, and normal control. The mean blood disappearance rate constant (K value) was 0.177±0.028/minute in normal control, In cirrhosis of the liver, it was markedly decreased which was suggestive of the reduced hepatic blood flow. 3. The ratio of 131 I-rose bengal blood disappearance half time to 198 Au colloid disappearance half time was 1.68±0.20 in normal control, 1.82±0.31 in cirrhosis of the liver, 3.80±0.82 in acute hepatitis, and 3.01±0.54 in obstructive jaundice. The ratios in acute hepatitis and obstructive jaundice were remarkably higher than those in normal control and cirrhosis of the liver. 4. There was a significant correlation between the blood disappearance half time of 131 I-rose bengal and that of 198 Au colloid in

  2. Principles of chemical kinetics

    CERN Document Server

    House, James E

    2007-01-01

    James House's revised Principles of Chemical Kinetics provides a clear and logical description of chemical kinetics in a manner unlike any other book of its kind. Clearly written with detailed derivations, the text allows students to move rapidly from theoretical concepts of rates of reaction to concrete applications. Unlike other texts, House presents a balanced treatment of kinetic reactions in gas, solution, and solid states. The entire text has been revised and includes many new sections and an additional chapter on applications of kinetics. The topics covered include quantitative rela

  3. Introduction to chemical kinetics

    CERN Document Server

    Soustelle, Michel

    2013-01-01

    This book is a progressive presentation of kinetics of the chemical reactions. It provides complete coverage of the domain of chemical kinetics, which is necessary for the various future users in the fields of Chemistry, Physical Chemistry, Materials Science, Chemical Engineering, Macromolecular Chemistry and Combustion. It will help them to understand the most sophisticated knowledge of their future job area. Over 15 chapters, this book present the fundamentals of chemical kinetics, its relations with reaction mechanisms and kinetic properties. Two chapters are then devoted to experimental re

  4. Kinetic equation solution by inverse kinetic method

    International Nuclear Information System (INIS)

    Salas, G.

    1983-01-01

    We propose a computer program (CAMU) which permits to solve the inverse kinetic equation. The CAMU code is written in HPL language for a HP 982 A microcomputer with a peripheral interface HP 9876 A ''thermal graphic printer''. The CAMU code solves the inverse kinetic equation by taking as data entry the output of the ionization chambers and integrating the equation with the help of the Simpson method. With this program we calculate the evolution of the reactivity in time for a given disturbance

  5. Non-kinetic capabilities: complementing the kinetic prevalence to targeting

    OpenAIRE

    Ducheine, P.

    2014-01-01

    Targeting is used in military doctrine to describe a military operational way, using (military) means to influence a target (or addressee) in order to achieve designated political and/or military goals. The four factors italicized are used to analyse non-kinetic targeting, complementing our knowledge and understanding of the kinetic prevalence. Paradoxically, non-kinetic targeting is not recognized as a separate concept: kinetic and non-kinetic are intertwined facets of targeting. Kinetic tar...

  6. Disorders of Bone Mineral Density and Secondary Osteoporosis in Pathology of Hepatobiliary System and Gastrointestinal Tract: at the Crossing of Problems

    Directory of Open Access Journals (Sweden)

    I.Yu. Golovach

    2012-08-01

    Full Text Available This review article covers the issues of development of osteoporosis and disorders of bone mineral density in patients with various gastroenterological and hepatobiliary diseases. The article emphasized that the osteoporosis may be associated with many somatic diseases, especially of the digestive tract. Such situation requires participation of therapeutists and gastroenterologists in rehabilitation health care programs. According to the practical guidelines of the World Organization of Gastroenterology (OMGE, 2004 list of chronic diseases of the digestive system triggering the dangerous development of osteoporosis includes short bowel syndrome, postgastrectomy syndrome, inflammatory bowel disease, celiac disease, cholestatic liver disease, as well as glucocorticoid-induced osteoporosis. The etiology and pathogenesis of lower bone mineral density in patients with chronic diseases of the digestive system include, besides population-based risk factors, processes associated with disorders of vitamin D conversion, which leads to reduction of the absorption of calcium, magnesium and phosphorus in the intestine and increase of their excretion by the kidneys. Hypocalcemia results in activation of the parathyroid glands and secondary hyperparathyroidism, and against the background of chronic inflammation increases the activity of cytokines, in particular tumor necrosis factor α and interleukins-1, -6, having bone resorptive action. The main risk factors for osteoporosis for various diseases associated with the peculiarities of the digestive tract’ disease were identified.

  7. LIVER ULTRASONOGRAPHY IN DOLPHINS: USE OF ULTRASONOGRAPHY TO ESTABLISH A TECHNIQUE FOR HEPATOBILIARY IMAGING AND TO EVALUATE METABOLIC DISEASE-ASSOCIATED LIVER CHANGES IN BOTTLENOSE DOLPHINS (TURSIOPS TRUNCATUS).

    Science.gov (United States)

    Seitz, Kelsey E; Smith, Cynthia R; Marks, Stanley L; Venn-Watson, Stephanie K; Ivančić, Marina

    2016-12-01

    The objective of this study was to establish a comprehensive technique for ultrasound examination of the dolphin hepatobiliary system and apply this technique to 30 dolphins to determine what, if any, sonographic changes are associated with blood-based indicators of metabolic syndrome (insulin greater than 14 μIU/ml or glucose greater than 112 mg/dl) and iron overload (transferrin saturation greater than 65%). A prospective study of individuals in a cross-sectional population with and without elevated postprandial insulin levels was performed. Twenty-nine bottlenose dolphins ( Tursiops truncatus ) in a managed collection were included in the final data analysis. An in-water ultrasound technique was developed that included detailed analysis of the liver and pancreas. Dolphins with hyperinsulinemia concentrations had larger livers compared with dolphins with nonelevated concentrations. Using stepwise, multivariate regression including blood-based indicators of metabolic syndrome in dolphins, glucose was the best predictor of and had a positive linear association with liver size (P = 0.007, R 2 = 0.24). Bottlenose dolphins are susceptible to metabolic syndrome and associated complications that affect the liver, including fatty liver disease and iron overload. This study facilitated the establishment of a technique for a rapid, diagnostic, and noninvasive ultrasonographic evaluation of the dolphin liver. In addition, the study identified ultrasound-detectable hepatic changes associated primarily with elevated glucose concentration in dolphins. Future investigations will strive to detail the pathophysiological mechanisms for these changes.

  8. Differentiation of focal nodular hyperplasia from hepatocellular adenoma: Role of the quantitative analysis of gadobenate dimeglumine-enhanced hepatobiliary phase MRI.

    Science.gov (United States)

    Roux, Marion; Pigneur, Frederic; Calderaro, Julien; Baranes, Laurence; Chiaradia, Mélanie; Tselikas, Lambros; Decaens, Thomas; Costentin, Charlotte; Laurent, Alexis; Azoulay, Daniel; Mallat, Ariane; Zafrani, Elie-Serge; Rahmouni, Alain; Luciani, Alain

    2015-11-01

    To determine the value of quantitative analysis of the hepatobiliary phase (HBP) in gadobenate dimeglumine (Gd-BOPTA)-enhanced magnetic resonance imaging (MRI) to differentiate focal nodular hyperplasia (FNH) from hepatocellular adenoma (HCA). Thirty-eight patients bearing 67 lesions (40 FNH; 27 HCA) were retrospectively included in this Institutional Review Board-approved study. The same volumetric interpolated breath-hold examination (VIBE) T1 -weighted sequences were performed before and after contrast injection on a 1.5T MRI, with HBP images acquired with a mean delay of 80 minutes (range 60-120 min). After a visual assessment of lesions enhancement (qualitative HBP analysis), the HBP signal intensity ratio (SIR) and the lesion-to-liver contrast enhancement ratio (LLCER) were calculated for each lesion by two observers (Mann-Whitney test). The sensitivities, specificities (receiver operating characteristic [ROC] curve analysis) and interobserver correlation (intraclass coefficient, ICC) of quantitative HBP analysis were determined. All FNH and 44.4% of HCA appeared hyper- or isointense relative to the adjacent liver on qualitative HBP analysis. The mean SIR (P Quantitative LLCER assessment allows an accurate differentiation of FNH from HCA, even in hyper- or isointense HCA on HBP images. © 2015 Wiley Periodicals, Inc.

  9. Added value of smooth hypointense rim in the hepatobiliary phase of gadoxetic acid-enhanced MRI in identifying tumour capsule and diagnosing hepatocellular carcinoma

    Energy Technology Data Exchange (ETDEWEB)

    An, Chansik; Han, Kyunghwa; Choi, Jin-Young; Park, Mi-Suk; Kim, Myeong-Jin [Yonsei University College of Medicine, Department of Radiology, Research Institute of Radiological Science, Seoul (Korea, Republic of); Rhee, Hyungjin [Yonsei University College of Medicine, Department of Pathology, Brain Korea 21 PLUS Project for Medical Science, Integrated Genomic Research Center for Metabolic Regulation, Seoul (Korea, Republic of); Park, Young-Nyun [Yonsei University College of Medicine, Department of Pathology, Brain Korea 21 PLUS Project for Medical Science, Integrated Genomic Research Center for Metabolic Regulation, Seoul (Korea, Republic of); Yonsei University College of Medicine, Severance Biomedical Science Institute, Seoul (Korea, Republic of); Park, Sumi [National Health Insurance Service Ilsan Hospital, Department of Radiology, Goyang (Korea, Republic of)

    2017-06-15

    To examine the added value of considering smooth hypointense rim in the hepatobiliary phase (HBP) of gadoxetic acid-enhanced MRI as capsule appearance for diagnosing tumour capsules and hepatocellular carcinoma (HCC). A total of 377 hepatic lesions (330 HCCs, 35 non-HCC malignancies and 12 benign) were included from 345 patients who underwent resection after MRI between January 2008 and December 2011. Two radiologists assessed the presence or absence of conventional capsule appearance and smooth hypointense rim in the HBP, and categorized each hepatic lesion according to the Liver Imaging Reporting and Data System. Difference in diagnostic performance was evaluated using the generalized estimating equation method. For identifying capsule, the sensitivity and accuracy of HBP hypointense rim were significantly higher than those of conventional capsule appearance (81.5 % vs. 57.8 % and 76.1 % vs. 59.4 %, respectively; P < 0.001). For diagnosing HCC, the sensitivity and accuracy of LR-5 or LR-5 V were significantly higher when the HBP hypointense rim was also considered capsule appearance (83 % vs. 72.7 % and 84.1 % vs. 75.1 %, respectively; P < 0.001), with the same specificity (91.5 %). Regarding smooth hypointense rim in the HBP as capsule appearance could improve the detection of tumour capsule and the diagnosis of HCC. (orig.)

  10. Diagnosis of hepatobiliary disease by Technetium-99m-HIDA and BIDA cholecystography in 210 patients treated at ''Soroka Medical Center'' between 1977 - 1979

    International Nuclear Information System (INIS)

    Garty, I.; Silberman, C.

    1979-01-01

    Cholescintigraphy experience with Tc 99 m-HIDA and BIDA in 210 patients with gallbladder disease treated at the Soroka Medical Center between the years 1977 - 1979 is described. In this work the utility of the method in both acute and chronic cholecystitis and hepatobiliary disease in the presence of jaundice up to 26 mg% of Bilirubin is demosntrated. Four patients were diagnosed as suffering from Atresia of biliary duct. The most common findings in our series are: all normal gallbladders exhibited filling; absence of visualization indicated gallbladder disease and/or cystic duct obstruction; visualization of the gallbladder after a fatty meal-induced emptying excluded an obstructed cystic duct and acute cholecystitis; a definite diagnosis of hepato-cellular disease, partial and complete obstruction, is possible in jaundiced patients with hyperbilirubinemia. No diagnostic failures due to too low concentration of the tracer in the biliary tract, were observed. Radiation exposure is somewhat greater than in cholecystography and cholangiography. Cholescintigraphy is a suitable complementary or alternative investigation to intravenous cholangiography, especially when poor excretion of the contrast medium or adverse reaction impair the result of the latter. In some of our cases this method proved to be the first choice non invasive procedure, especially in cases with high serum bilirubin up to 26 mg%. (B.G.)

  11. Assessment of Liver Function Using 99mTc-Mebrofenin Hepatobiliary Scintigraphy in ALPPS (Associating Liver Partition and Portal Vein Ligation for Staged Hepatectomy

    Directory of Open Access Journals (Sweden)

    Kasia P. Cieslak

    2015-11-01

    Full Text Available ALPPS (associating liver partition and portal vein ligation for staged hepatectomy is a new surgical technique for patients in whom conventional treatment is not feasible due to insufficient future remnant liver (FRL. During the first stage of ALPPS, accelerated hypertrophy of the FRL is induced by ligation of the portal vein and in situ split of the liver. In the second stage, the deportalized liver is removed when the FRL volume has reached ≥25% of total liver volume. However, FRL volume does not necessarily reflect FRL function. 99mTc-mebrofenin hepatobiliary scintigraphy (HBS with SPECT-CT is a quantitative test enabling regional assessment of parenchymal uptake function using a validated cut-off value for the prediction of postoperative liver failure (2.7%/min/m2. This paper describes the changes in FRL function and FRL volume in a 79-year-old patient diagnosed with metachronous colonic liver metastases who underwent ALPPS. We have observed a substantial difference between the increase in FRL volume and FRL function suggesting that HBS with SPECT-CT enables monitoring of the FRL function and could be a useful tool in the timing of resection in the second stage of the ALPPS procedure.

  12. Hepatobiliary delivery of polyaminopolycarboxylate chelates: Synthesis and characterization of a cholic acid conjugate of EDTA and biodistribution and imaging studies with its indium-111 chelate

    Energy Technology Data Exchange (ETDEWEB)

    Betebenner, D.A.; Carney, P.L.; Zimmer, A.M.; Kazikiewicz, J.M.; Bruecher, E.S.; Sherry, A.D.; Johnson, D.K. (Abbott Laboratories, Abbott Park, Illinois (USA))

    1991-03-01

    A conjugate in which the steroid nucleus of cholic acid was linked to EDTA via an 11-atom spacer was obtained by reacting the succinimidyl ester of cholic acid with the amine formed by reaction of a benzyl isothiocyanate derivative of EDTA with N-(tert-butoxycarbonyl)ethylenediamine and subsequent deprotection. Potentiometric titration studies with model complexes showed that the EDTA moiety retained the ability to form 1:1 chelates of high thermodynamic stability, although formation constants were some 3-4 log K units lower for complexes of the conjugate than for the analogous chelates with underivatized EDTA. A complex formed between the cholic acid-EDTA conjugate and 111InIII was clearly rapidly into the liver when injected iv into mice, with subsequent excretion from the liver into the gastrointestinal tract being complete within 1 h of injection. Radioscintigraphic imaging studies conducted in a rabbit given the 111In-labeled conjugate also showed early liver uptake followed by rapid clearance from the liver into the intestine, with good visualization of the gallbladder in images obtained at 20-25 min postinjection. It is concluded that conjugation to cholic acid provides a useful means for the hepatobiliary delivery of EDTA chelates that otherwise exhibit predominantly extracellular distribution and renal clearance.

  13. Reinterpretation of radiological imaging in patients referred to a tertiary referral centre with a suspected pancreatic or hepatobiliary malignancy: impact on treatment strategy

    International Nuclear Information System (INIS)

    Tilleman, Esther H.B.M.; Gulik, Thomas M. van; Gouma, Dirk J.; Phoa, Saffire S.K.S.; Delden, Otto M. van; Lameris, Johan S.; Rauws, Erik A.J.

    2003-01-01

    Our objective was to determine the clinical importance of reinterpretation of radiological investigations performed in a referring hospital and the value of additional investigations in a referral centre. A panel of four experts retrospectively evaluated the technical quality of radiological investigations and made reinterpretation reports, of 78 patients referred with a suspected pancreatic or hepatobiliary malignancy. The value of additional radiological investigations performed in the referral centre was assessed. The quality of ultrasound and CT examinations was sufficient for reinterpretation in (36 of 69) 52% and (42 of 60) 70%, respectively. The reinterpretation reports of the ultrasound investigations were scored as ''in accordance'' in (30 of 36) 83%, as ''minor discordance'' in (3 of 36) 8% and as ''major discordance'' in (3 of 36) 8%. For CT proportions of (29 of 42) 69%, (8 of 42) 19% and (5 of 42) 12%, respectively, were found. Additional ultrasound (n=55) showed no additional findings in 16%, minor additional findings in 53% and major additional findings in 31% of cases. For additional spiral CT scan (n=47) results were of 21, 47 and, 32%, respectively. Reinterpretation of ultrasound and CT resulted in a change in treatment strategy for 7 patients (9%). Additional ultrasound or CT resulted in a change in treatment strategy for 24 patients (30%). Improved communication and reinterpretation of radiological investigations may reduce unnecessary referral. (orig.)

  14. Periportal lymphatic system on post-hepatobiliary phase Gd-EOB-DTPA-enhanced MR imaging in normal subjects and patients with chronic hepatitis C.

    Science.gov (United States)

    Yamada, Yasunari; Matsumoto, Shunro; Mori, Hiromu; Takaji, Ryo; Kiyonaga, Maki; Hijiya, Naoki; Tanoue, Rika; Tomonari, Kenichiro; Tanoue, Shuichi; Hongo, Norio; Ohta, Masayuki; Seike, Masataka; Inomata, Masafumi; Murakami, Kazunari; Moriyama, Masatsugu

    2017-10-01

    We sought to evaluate visualization of periportal lymphatics and lymph nodes (lymphatic system) on Gd-EOB-DTPA-enhanced magnetic resonance (MR) images using a fat-suppressed T2-weighted sequence with 3-dimensional (3D) volume isotropic turbo spin echo acquisition (VISTA) at 3.0 T in normal subjects and patients with chronic hepatitis C. MR imaging was performed in 254 subjects between June 2013 and May 2016. After applying inclusion and exclusion criteria, the final population was 31 normal subjects and 34 patients with chronic hepatitis C. Images were acquired after the hepatobiliary phase following intravenous administration of Gd-EOB-DTPA, which causes signal loss in the bile ducts, to facilitate the visualization of the periportal lymphatic system. Two radiologists assessed the visualization of the periportal lymphatic system in 31 normal subjects. The axial dimensions of the main periportal lymphatic system in normal subjects were measured and compared with those of 34 patients with chronic hepatitis C using the Mann-Whitney U-test, and their correlation with a hepatic fibrosis marker, the Fibrosis-4 (FIB-4), was assessed using Spearman's rank correlation test. The periportal lymphatic system was detected as high signal intensity areas surrounding the portal vein up to the third branches by each reader in all normal subjects. The axial dimensions of the main periportal lymphatic system in patients with chronic hepatitis C were significantly larger than those in normal subjects (p system and the degree of hepatic fibrosis.

  15. Irreversible processes kinetic theory

    CERN Document Server

    Brush, Stephen G

    2013-01-01

    Kinetic Theory, Volume 2: Irreversible Processes deals with the kinetic theory of gases and the irreversible processes they undergo. It includes the two papers by James Clerk Maxwell and Ludwig Boltzmann in which the basic equations for transport processes in gases are formulated, together with the first derivation of Boltzmann's ""H-theorem"" and a discussion of this theorem, along with the problem of irreversibility.Comprised of 10 chapters, this volume begins with an introduction to the fundamental nature of heat and of gases, along with Boltzmann's work on the kinetic theory of gases and s

  16. Thermal kinetic inductance detector

    Science.gov (United States)

    Cecil, Thomas; Gades, Lisa; Miceli, Antonio; Quaranta, Orlando

    2016-12-20

    A microcalorimeter for radiation detection that uses superconducting kinetic inductance resonators as the thermometers. The detector is frequency-multiplexed which enables detector systems with a large number of pixels.

  17. Inhibition of P-glycoprotein and multidrug resistance-associated protein 2 regulates the hepatobiliary excretion and plasma exposure of thienorphine and its glucuronide conjugate

    Directory of Open Access Journals (Sweden)

    Ling-Lei Kong

    2016-08-01

    Full Text Available Thienorphine (TNP is a novel partial opioid agonist that has completed phase II clinical evaluation as a promising drug candidate for the treatment of opioid dependence. Previous studies have shown that TNP and its glucuronide conjugate (TNP-G undergo significant bile excretion. The purpose of this study was to investigate the roles of efflux transporters in regulating biliary excretion and plasma exposure of TNP and TNP-G. An ATPase assay suggested that TNP and TNP-G were substrates of P-gp and MRP2, respectively. The in vitro data from rat hepatocytes showed that bile excretion of TNP and TNP-G was regulated by the P-gp and MRP2 modulators. The accumulation of TNP and TNP-G in HepG2 cells significantly increased by the treatment of mdr1a or MRP2 siRNA for P-gp or MRP2 modulation. In intact rats, the bile excretion and pharmacokinetic profiles of TNP and TNP-G were remarkably changed with tariquidar and probenecid pretreatment, respectively. Tariquidar increased the Cmax and AUC0-t and decreased MRT and T1/2 of TNP, whereas probenecid decreased the plasma exposure of TNP-G and increased its T1/2. Knockdown P-gp and MRP2 function using siRNA significantly increased the plasma exposure of TNP and TNP-G and reduced their mean retention time in mice. These results indicated the important roles of P-gp and MRP2 in hepatobiliary excretion and plasma exposure of TNP and TNP-G. Inhibition of the efflux transporters may affect the pharmacokinetics of TNP and result in a drug-drug interaction between TNP and the concomitant transporter inhibitor or inducer in clinic.

  18. Noninvasive diagnosis of hepatocellular carcinoma on gadoxetic acid-enhanced MRI: can hypointensity on the hepatobiliary phase be used as an alternative to washout?

    Energy Technology Data Exchange (ETDEWEB)

    Joo, Ijin; Lee, Dong Ho; Jeon, Ju Hyeon [Seoul National University Hospital, Department of Radiology, 101 Daehak-ro, Jongno-gu, Seoul (Korea, Republic of); Seoul National University College of Medicine, Department of Radiology, 103 Daehak-ro, Jongno-gu, Seoul (Korea, Republic of); Lee, Jeong Min; Han, Joon Koo; Choi, Byung Ihn [Seoul National University Hospital, Department of Radiology, 101 Daehak-ro, Jongno-gu, Seoul (Korea, Republic of); Seoul National University College of Medicine, Department of Radiology, 103 Daehak-ro, Jongno-gu, Seoul (Korea, Republic of); Seoul National University Medical Research Center, Institute of Radiation Medicine, 103 Daehak-ro, Jongno-gu, Seoul (Korea, Republic of)

    2015-10-15

    To determine which dynamic phase(s) of gadoxetic acid-enhanced MRI is most appropriate to assess ''washout'' in the noninvasive diagnosis of hepatocellular carcinoma (HCC) based on hemodynamic pattern. In this retrospective cohort study, 288 consecutive patients with chronic liver disease presented with 387 arterially enhancing nodules (292 HCCs, 95 non-HCCs) (≥1 cm) on gadoxetic acid-enhanced MRI. All HCCs were confirmed by histopathology or by their typical enhancement pattern on dynamic liver CT. MR imaging diagnosis of HCC was made using criteria of arterial enhancement and hypointensity relative to the surrounding parenchyma (1) on the portal-venous phase (PVP), (2) on the PVP and/or transitional phase (TP), or (3) on the PVP and/or TP, and/or hepatobiliary phase (HBP). For the noninvasive diagnosis of HCC, criterion 1 provided significantly higher specificity (97.9 %; 95 % confidence interval, 92.6 - 99.7 %) than criteria 2 (86.3 %; 77.7 - 92.5 %), or 3 (48.4 %; 38.0 - 58.9 %). Conversely, higher sensitivity was obtained with criterion 3 (93.8 %; 90.4 - 96.3 %) than with criterion 2 (86.6 %; 82.2 - 90.3 %) or 1 (70.9 %; 65.3 - 76.0 %). To make a sufficiently specific diagnosis of HCC using gadoxetic acid-enhanced MRI based on typical enhancement features, washout should be determined on the PVP alone rather than combined with hypointensity on the TP or HBP. (orig.)

  19. Hepato-biliary effects of mucoviscidosis: use of Mebrofenine scintigraphy; Atteinte hepato-biliaire de la mucoviscidose: interet de la scintigraphie a la Mebrofenine

    Energy Technology Data Exchange (ETDEWEB)

    Perrin-Fayolle, O.; Morelec, I. [Medecine Nucleaire, C.H. Lyon-Sud, Lyon (France); Gilly, R. [Pediatrie, C.H. Lyon-Sud, Lyon (France); Roche, S.; Sappey-Marinier, D.; Briere, J.; Bonmartin, A. [Medecine Nucleaire, C.H. Lyon-Sud, Lyon (France); Bellon, G. [Pediatrie, C.H. Lyon-Sud, Lyon (France)

    1997-12-31

    The objective of this work is the scintigraphic profile of patients afflicted with mucoviscidosis with portal hypertension (PHT) and the questions whether there exists a criterion to characterized the first stage of fibrosis as well as whether exist in this stage lesions of hepato cellular insufficiency (HCI). The method of the work implied the study of the dynamics of 60 minutes after injecting 40 - 120 MBq of Mebrofenine in 18 patients, 9 presenting a certain PHT, and 9, signs of hepatobiliary affliction without genuine PHT. In the population with PHT, all patients presented a splenomegaly, a very heterogeneous fixation and a retention of the tracer in the intrahepatic-biliary tracts (IHBT) with augmentation of T{sub 1/2} in 5 cases; 8 presented a diminution of the hepatic extraction fraction (HEF), serving as control of HCI. In the population without PHT 2 patients are normal. In the other seven, the most frequently found anomalies are the accumulation of tracer in the IHBT (5/7) and the hepatic heterogeneity (4/7). HEF is low in one case. No dilatation was visible by echography. In conclusion, the accumulation in the IHBT (14 patients, 9 PHT and 5 non PHT) expresses the presence of a functional stasis without organic effects (no echographic dilatation), consequence of a obstruction of biliary ducts by mucus plugs due to dehydration of the bile. The HEF, labeller of HCI, is low in 8 PHT and in one non-PHT, hence tardy in the evolution of the disease, the portal cirrhosis occurring at more on less long term. This parameter can not be considered as a labeller of fibrosis, on the contrary, the accumulation of this tracer in the IHBT and the hepatic heterogeneity seems more interesting for an early detection and start of a preventive treatment

  20. Utility of hepatobiliary scintigraphy in diagnosing or excluding biliary atresia in premature neonates and full-term infants with conjugated hyperbilirubinemia who received parenteral nutrition.

    Science.gov (United States)

    Barseghyan, Karine; Ramanathan, Rangasamy; Chavez, Thomas; Harlan, Susan; Lin, Chuan-Hao; Mitsinikos, Tania; McLean, Claire

    2017-08-31

    Hepatobiliary scintigraphy (HBS) is used to aid in the diagnosis of Biliary Atresia in full-term infants with conjugated hyperbilirubinemia. There is little information on the utility of the HBS in premature infants with conjugated hyperbilirubinemia and infants with parenteral nutrition associated cholestasis (PNAC). The purpose of this study is to assess the utility of HBS in differentiating Biliary Atresia and PNAC in premature neonates and full-term infants who received parenteral nutrition (PN). Retrospective data collection and analysis on infants who developed conjugated hyperbilirubinemia and had HBS performed during their stay at level IV neonatal intensive care unit between 2005 and 2015. A total of 20 patients with exposure to PN had HBS; two patients were confirmed to have Biliary Atresia. There were no statistically significant differences between patients with Biliary Atresia versus PNAC in demographics, days on PN, or gamma glutamyl-transferase levels. Stool color was statistically significantly different between the two groups; patients with Biliary Atresia had acholic stools more consistently than patients without Biliary Atresia. HBS had 100% sensitivity, 17% specificity, positive-predictive value of 12%, and a negative-predictive value (NPV) of 100%. These data indicate that the ability of HBS to aid in diagnosing Biliary Atresia is poor in a population of preterm neonates and full-term infants with PNAC. Although there is 100% sensitivity, the poor specificity (17%) should be acknowledged when utilizing HBS to diagnose Biliary Atresia in this vulnerable patient population. NPV of 100% is helpful in ruling out Biliary Atresia in this population.

  1. Hepatobiliary transit times of gadoxetate disodium (Primovist) for protocol optimization of comprehensive MR imaging of the biliary system-What is normal?

    International Nuclear Information System (INIS)

    Ringe, Kristina I.; Husarik, Daniela B.; Gupta, Rajan T.; Boll, Daniel T.; Merkle, Elmar M.

    2011-01-01

    Objective: The purpose of this study was to determine transit times for excretion of Gd-EOB-DTPA into different segments of the hepatobiliary system in patients with normal liver function. Methods: This retrospective study was IRB approved with a waiver of consent granted. 61 patients (39 female, 22 male, mean age 52.5 years) with normal liver and renal function who underwent contrast enhanced hepatic MRI after injection of 10 mLGd-EOB-DTPA at 1.5 T and 3 T were included. Two readers evaluated all delayed images (3-20 min post contrast) for the presence of contrast agent in the intrahepatic bile ducts (IBD), the common bile duct (CBD), the gallbladder and the duodenum. A two-tailed, unpaired Student's t-test with p < 0.05 deemed significant was used to determine whether transit times were affected by patient gender, age or body mass index. Results: 20 min after contrast initiation, Gd-EOB-DTPA could be detected in the IBD and the CBD in all patients (100%); gallbladder reflux was visible in 53 (86.9%), duodenal excretion in 40 patients (65.5%), respectively. Mean transit times for contrast appearance in the various segments were as follows: IBD 12 min 13 s; CBD 12 min 27 s; gallbladder 13 min 32 s. Transit times were not significantly affected by patient gender, age or BMI. Conclusion: Within 20 min post contrast initiation, Gd-EOB-DTPA can be expected in the IBD and the CBD in patients with normal liver function. However, functional information about the sphincter Oddi complex can be ascertained only in about two thirds of these patients within this timeframe.

  2. Comparison of gadolinium Cy2DOTA, a new hepatobiliary agent, and gadolinium HP-DO3A, an extracellular agent, in healthy liver and metastatic disease

    International Nuclear Information System (INIS)

    Runge, V.M.; Wells, J.W.; Williams, N.M.

    1995-01-01

    A new gadolinium (Gd) chelate with preferential hepatobiliary uptake, Gd Cy 2 DOTA, was compared in two animal species with Gd HP-DO3A (gadoteridol), a clinically approved contrast agent with extracellular distribution. Liver enhancement was evaluated for these two contrast agents using magnetic resonance imaging, whereas an experimental model of metastatic disease was used to evaluate the agents' efficacy for liver-lesion delineation. The two agents were compared in four healthy Rhesus monkeys (eight studies) and five New Zealand White rabbits with implanted VX-2 liver tumors (ten studies). The contrast dose was 0.1 mmol/kg, with the agents given in random order and at least 72 hours between contrast injections. Breathhold T1-weighted spin echo scans were obtained at 1.5 tesla (T) before and after contrast was administered. Postcontrast scans were obtained 1 to 90 minutes after injection in the monkeys and 1 to 240 minutes after injection in the rabbits. Prolonged hepatic enhancement, superior in degree to that with Gd HP-DO3A, was noted to both monkeys and rabbits after injection of Gd Cy 2 DOTA. Two minutes after contrast, liver SI was 1.94 ± 0.05 with Gd Cy 2 DOTA compared with 1.5 ± 0.05 with Gd HP-DO3A in monkeys. Sixty minutes after contrast, liver SI was 1.60 ± 0.09 compared with 1.20 ± 0.02. The difference between agents was significant at all times from 2 to 60 minutes after contrast injection (P 2 DOTA but not with Gd HP-DO3A. The maximum improvement in lesion conspicuity (rabbit) occurred 45 minutes after injection of Gd Cy 2 DOTA and 5 minutes after injection of Gd HP-DO3A. 22 refs., 12 figs

  3. Multiple alternative substrate kinetics.

    Science.gov (United States)

    Anderson, Vernon E

    2015-11-01

    The specificity of enzymes for their respective substrates has been a focal point of enzyme kinetics since the initial characterization of metabolic chemistry. Various processes to quantify an enzyme's specificity using kinetics have been utilized over the decades. Fersht's definition of the ratio kcat/Km for two different substrates as the "specificity constant" (ref [7]), based on the premise that the important specificity existed when the substrates were competing in the same reaction, has become a consensus standard for enzymes obeying Michaelis-Menten kinetics. The expansion of the theory for the determination of the relative specificity constants for a very large number of competing substrates, e.g. those present in a combinatorial library, in a single reaction mixture has been developed in this contribution. The ratio of kcat/Km for isotopologs has also become a standard in mechanistic enzymology where kinetic isotope effects have been measured by the development of internal competition experiments with extreme precision. This contribution extends the theory of kinetic isotope effects to internal competition between three isotopologs present at non-tracer concentrations in the same reaction mix. This article is part of a special issue titled: Enzyme Transition States from Theory and Experiment. Published by Elsevier B.V.

  4. Erbium hydride decomposition kinetics.

    Energy Technology Data Exchange (ETDEWEB)

    Ferrizz, Robert Matthew

    2006-11-01

    Thermal desorption spectroscopy (TDS) is used to study the decomposition kinetics of erbium hydride thin films. The TDS results presented in this report are analyzed quantitatively using Redhead's method to yield kinetic parameters (E{sub A} {approx} 54.2 kcal/mol), which are then utilized to predict hydrogen outgassing in vacuum for a variety of thermal treatments. Interestingly, it was found that the activation energy for desorption can vary by more than 7 kcal/mol (0.30 eV) for seemingly similar samples. In addition, small amounts of less-stable hydrogen were observed for all erbium dihydride films. A detailed explanation of several approaches for analyzing thermal desorption spectra to obtain kinetic information is included as an appendix.

  5. Quantum kinetic theory

    CERN Document Server

    Bonitz, Michael

    2016-01-01

    This book presents quantum kinetic theory in a comprehensive way. The focus is on density operator methods and on non-equilibrium Green functions. The theory allows to rigorously treat nonequilibrium dynamics in quantum many-body systems. Of particular interest are ultrafast processes in plasmas, condensed matter and trapped atoms that are stimulated by rapidly developing experiments with short pulse lasers and free electron lasers. To describe these experiments theoretically, the most powerful approach is given by non-Markovian quantum kinetic equations that are discussed in detail, including computational aspects.

  6. Relativistic Kinetic Theory

    Science.gov (United States)

    Vereshchagin, Gregory V.; Aksenov, Alexey G.

    2017-02-01

    Preface; Acknowledgements; Acronyms and definitions; Introduction; Part I. Theoretical Foundations: 1. Basic concepts; 2. Kinetic equation; 3. Averaging; 4. Conservation laws and equilibrium; 5. Relativistic BBGKY hierarchy; 6. Basic parameters in gases and plasmas; Part II. Numerical Methods: 7. The basics of computational physics; 8. Direct integration of Boltzmann equations; 9. Multidimensional hydrodynamics; Part III. Applications: 10. Wave dispersion in relativistic plasma; 11. Thermalization in relativistic plasma; 12. Kinetics of particles in strong fields; 13. Compton scattering in astrophysics and cosmology; 14. Self-gravitating systems; 15. Neutrinos, gravitational collapse and supernovae; Appendices; Bibliography; Index.

  7. Posture and theophylline kinetics.

    OpenAIRE

    Warren, J B; Cuss, F; Barnes, P J

    1985-01-01

    The effect of posture on theophylline kinetics was examined in six healthy men who took 450 mg slow-release aminophylline orally at the same time of day on two separate occasions. On one day they remained standing and on the other supine throughout. Plasma theophylline was measured hourly for 6 h from ingestion. Mean theophylline levels were significantly higher in the standing position at all times (P less than 0.01). We conclude that diurnal variation in theophylline kinetics can be explain...

  8. Tebuconazole photocatalytic degradation kinetics

    OpenAIRE

    Prestes, Thiago de Hermann; Gibbon, Danielle de Oliveira; Lansarin, Marla Azário; Moro, Celso Camilo

    2010-01-01

    The tebuconazole photocatalytic degradation kinetics was studied in a batch reactor using TiO2 (P25-Degussa) as catalyst and a high pressure mercury lamp. The photolysis, adsorption and irradiation effects in the reaction rate were evaluated. Afterward, the suspension catalyst concentration and initial pH to the maximum reaction rate was determined. It was observed that the reaction rate can be approached by a pseudo-first order, with a maximum kinetics constant at 260 mg L-1catalyst concentr...

  9. Thin-slice Free-breathing Pseudo-golden-angle Radial Stack-of-stars with Gating and Tracking T1-weighted Acquisition: An Efficient Gadoxetic Acid-enhanced Hepatobiliary-phase Imaging Alternative for Patients with Unstable Breath Holding.

    Science.gov (United States)

    Kajita, Kimihiro; Goshima, Satoshi; Noda, Yoshifumi; Kawada, Hiroshi; Kawai, Nobuyuki; Okuaki, Tomoyuki; Honda, Masatoshi; Matsuo, Masayuki

    2018-03-09

    To compare four free-breathing scan techniques for gadoxetic acid-enhanced hepatobiliary phase imaging with conventional breath-hold scans. Gadoxetic acid-enhanced hepatobiliary phase imaging with six image acquisition sets performed in 50 patients. Image acquisition sets included fat-suppressed 3D T 1 -weighted turbo field echo with free-breathing pseudo-golden-angle radial stack-of-stars (FBRS) acquisition, FBRS with track (FBRS T ), FBRS with gate and track (FBRS G&T ), thin-slice FBRS with gate and track (thin-slice FBRS G&T ), free-breathing Cartesian acquisition (Cartesian FB ), and breath-hold Cartesian acquisition (Cartesian BH ). Signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), and image quality compared to the six-image acquisition sets. Signal-to-noise ratio and CNR were significantly higher in FBRS, FBRS T , FBRS G&T , and thin-slice FBRS G&T than in Cartesian FB and Cartesian BH (P breath holding.

  10. Technetium-99m-labeled N-(2,6-dimethylphenylcarbamoylmethyl) iminodiacetic acid (/sup 99m/Tc HIDA): a new radiopharmaceutical for hepatobiliary imaging studies. [/sup 14/C, /sup 113/Sn

    Energy Technology Data Exchange (ETDEWEB)

    Ryan, J.; Cooper, M.; Loberg, M.; Harvey, E.; Sikorski, S.

    1977-10-01

    An easily formulated, stable kit preparation of technetium-99m HIDA, suitable for use in humans, was developed and tested in mice and dogs. The tracer was cleared rapidly from the blood and excreted predominantly by the liver in both species. In dogs, the hepatobiliary clearance of Tc-99m HIDA was significantly greater than that of C-14 HIDA and Sn-113 HIDA. The LD/sub 50/ for HIDA in mice, 168 mg/kg, exceeded the average human dose by a factor of 1000 on a per-weight basis. Blood clearance curves for Tc-99m HIDA in 12 normal subjects were biexponential with half-times of 4.6 +- 1.0 min and 31.5 +- 7.0 min, and cumulative 90-min urine samples contained 14.2 +- 1.8% of the injected dose. Images in normal subjects and nonjaundiced patients showed rapid concentration of tracer by the liver and activity was present within the biliary system in 10 to 20 min. In jaundiced patients, the tracer blood clearance was delayed and urinary excretion increased, but intestinal activity, indicating biliary patency, was imaged in those patients without complete focal obstruction of the common duct. Technetium-99m HIDA is a nontoxic radiopharmaceutical useful for clinical evaluation of hepatobiliary disorders in humans.

  11. Modeling chemical kinetics graphically

    NARCIS (Netherlands)

    Heck, A.

    2012-01-01

    In literature on chemistry education it has often been suggested that students, at high school level and beyond, can benefit in their studies of chemical kinetics from computer supported activities. Use of system dynamics modeling software is one of the suggested quantitative approaches that could

  12. CATALYTIC KINETIC SPECTROPHOTOMETRIC DETERMINATION ...

    African Journals Online (AJOL)

    Preferred Customer

    acetylchlorophosphonazo(CPApA) by hydrogen peroxide in 0.10 M phosphoric acid. A novel catalytic kinetic-spectrophotometric method is proposed for the determination of copper based on this principle. Copper(II) can be determined spectrophotometrically ...

  13. Kinetic energy budget details

    Indian Academy of Sciences (India)

    Abstract. This paper presents the detailed turbulent kinetic energy budget and higher order statistics of flow behind a surface-mounted rib with and without superimposed acoustic excitation. Pattern recognition technique is used to determine the large-scale structure magnitude. It is observed that most of the turbulence ...

  14. Kinetics and Catalysis Demonstrations.

    Science.gov (United States)

    Falconer, John L.; Britten, Jerald A.

    1984-01-01

    Eleven videotaped kinetics and catalysis demonstrations are described. Demonstrations include the clock reaction, oscillating reaction, hydrogen oxidation in air, hydrogen-oxygen explosion, acid-base properties of solids, high- and low-temperature zeolite reactivity, copper catalysis of ammonia oxidation and sodium peroxide decomposition, ammonia…

  15. SHORT COMMUNICATION KINETIC SPECTROPHOTOMETRIC ...

    African Journals Online (AJOL)

    Preferred Customer

    gingili paste, oat slice, sleeve-fish silk food samples. The determined results were in agreement with those by atomic absorption spectrometry. KEY WORDS: KEY WORDS: Iron, Catalytic kinetic spectrophotometry, p–Acetylarsenazo, Potassium periodate. INTRODUCTION. Iron is an important component for the human body.

  16. Point kinetics modeling

    International Nuclear Information System (INIS)

    Kimpland, R.H.

    1996-01-01

    A normalized form of the point kinetics equations, a prompt jump approximation, and the Nordheim-Fuchs model are used to model nuclear systems. Reactivity feedback mechanisms considered include volumetric expansion, thermal neutron temperature effect, Doppler effect and void formation. A sample problem of an excursion occurring in a plutonium solution accidentally formed in a glovebox is presented

  17. CATALYTIC KINETIC SPECTROPHOTOMETRIC DETERMINATION ...

    African Journals Online (AJOL)

    Based on the property that in 0.12 M sulfuric acid medium titanium(IV) catalyzes the discoloring reaction of DBS-arsenazo oxidized by potassium bromate, a new catalytic kinetic spectrophotometric method for the determination of trace titanium (IV) was developed. The linear range of the determination of titanium is

  18. Development and intra-institutional and inter-institutional validation of a comprehensive new hepatobiliary software: Part 1--Liver and gallbladder function.

    Science.gov (United States)

    Krishnamurthy, Gerbail T; Krishnamurthy, Shakuntala; Gambhir, Sanjiv Sam; Rodrigues, Cesar; Rosenberg, Jarrett; Schiepers, Christiaan; Buxton-Thomas, Muriel

    2009-12-01

    Food and Drug Administration-approved personal computer-based Krishnamurthy Hepato-Biliary Software for quantification of the liver and gallbladder function shows promise for consistently repeatable and reproducible results both within and between institutions, and may help to promote universal standardization of data acquisition and analysis in nuclear hepatology.

  19. Hepatobiliary phase images using gadolinium-ethoxybenzyl-diethylenetriamine penta-acetic acid-enhanced MRI as an imaging surrogate for the albumin–bilirubin grading system

    Energy Technology Data Exchange (ETDEWEB)

    Takatsu, Yasuo, E-mail: pcblue2@yahoo.co.jp [Department of Radiology, Osaka Red Cross Hospital, 5-30 Fudegasaki, Tennouji-ku, Osaka, 543-8555 (Japan); Division of Health Sciences, Graduate School of Medical Sciences, Kanazawa University, 5-11-80 Kodatsuno, Kanazawa, 920-0942 (Japan); Kobayashi, Satoshi, E-mail: satoshik@staff.kanazawa-u.ac.jp [Division of Health Sciences, Graduate School of Medical Sciences, Kanazawa University, 5-11-80 Kodatsuno, Kanazawa, 920-0942 (Japan); Miyati, Tosiaki, E-mail: ramiyati@mhs.mp.kanazawa-u.ac.jp [Division of Health Sciences, Graduate School of Medical Sciences, Kanazawa University, 5-11-80 Kodatsuno, Kanazawa, 920-0942 (Japan); Shiozaki, Toshiki, E-mail: shiozaki.toshiki@gmail.com [Department of Radiology, Osaka Red Cross Hospital, 5-30 Fudegasaki, Tennouji-ku, Osaka, 543-8555 (Japan)

    2016-12-15

    Objectives: To clarify the correlation between hepatobiliary phase (HBP) images using gadolinium-ethoxybenzyl-diethylenetriamine penta-acetic acid (Gd-EOB-DTPA) and albumin–bilirubin (ALBI) grading system. Materials and methods: We evaluated 220 consecutive patients who underwent liver magnetic resonance imaging with Gd-EOB-DTPA. Quantitative liver–spleen contrast ratio (Q-LSC) was calculated in HBP images approximately 20 min after Gd-EOB-DTPA administration. To evaluate the degree of association between Q-LSC and ALBI grade, the Child–Pugh (C-P) score was used for comparison. Correlation coefficients were calculated, and median Q-LSC values were compared with the C-P scores and ALBI grades. The Steel–Dwass multiple comparison test was used for statistical analysis. Results: The correlation coefficient between Q-LSC and C-P score was −0.35, P < 0.0001, and the ALBI grade was −0.61, P < 0.0001. Q-LSC of overall median, C-P A, B, and C were 1.94, 1.91, 1.96, and 1.33, respectively. The differences between C-P A and C-P B, C-P B and C-P C, and C-P A and C-P C were P = 0.999, 0.126, and 0.149, respectively. Q-LSC of the overall median, ALBI grade 1, 2, and 3 were 1.94, 2.12, 1.69, and 1.30, respectively. The differences between ALBI grades 1 and 2, 2 and 3, and 1 and 3 were P < 0.0001, P = 0.0466, and P = 0.0035, respectively. Q-LSC was better correlated and discriminated by ALBI grade than C-P score. Conclusion: A strong correlation was observed between Q-LSC of an HBP image with Gd-EOB-DTPA and ALBI grade; HBP imaging could be a surrogate for the ALBI grade.

  20. Quantitative Expression of Hepatobiliary Transporters and Functional Uptake of Substrates in Hepatic Two-Dimensional Sandwich Cultures: A Comparative Evaluation of Upcyte and Primary Human Hepatocytes.

    Science.gov (United States)

    Schaefer, Michelle; Morinaga, Gaku; Matsui, Akiko; Schänzle, Gerhard; Bischoff, Daniel; Süssmuth, Roderich D

    2018-02-01

    Deficient functional expression of drug transporters incapacitates most hepatic cell lines as a reliable tool for evaluating transporter-mediated drug-drug interactions. Recently, genetically modified cells (referred to as upcyte hepatocytes) have emerged as an expandable, noncancerous source of human hepatic cells. Herein, we quantified mRNA and protein levels of key hepatobiliary transporters and we assessed associated uptake activity in short- and long-term cultures of upcyte human hepatocytes (UHH) in comparison to cryopreserved primary human hepatocytes (cPHH). Expression of canalicular efflux pumps, such as MRD1/ ABCB1 , MATE1/ SLC47A1 , and MRP2/ ABCC2 , was relatively well preserved in UHH. By contrast, long-term cultivation of UHH in a two-dimensional sandwich configuration [sandwich-cultured upcyte human hepatocytes (SCUHH)] was required to upregulate organic anion-transporting polypeptide OATP1B1/ SLCO1B1 , OATP2B1/ SLCO2B1 , NTCP/ SLC10A1 , and OCT1/ SLC22A1 mRNA expression, which correlated well with respective protein abundances. However, mRNA and protein levels of sinusoidal solute carrier transporters, except for NTCP and OATP2B1, remained low in SCUHH compared to sandwich-cultured cPHH. OCT1- and NTCP-mediated uptake of N -methyl-4-phenylpyridinium acetate and taurocholate was demonstrated in both hepatic models, whereas active uptake of OATP1B1/1B3-selective marker substrates, paralleled by markedly reduced SLCO1B1/1B3 expression, were not detectable in SCUHH. Uptake studies under Na + -depletion and excess of taurocholate confirmed the presence of functional NTCP protein and indicated that NTCP, apart from OATP2B1, contributed substantially to the overall hepatic uptake of rosuvastatin in SCUHH. In conclusion, our data suggest that SCUHH, despite their limitation for evaluating OATP1B1/1B3-mediated transport processes, retain NTCP, OATP2B1, and OCT1 transport activities and thus may be considered as a tool for elucidating compensatory uptake

  1. Kinetic Damage from Meteorites

    Science.gov (United States)

    Cooke, W.; Brown, P.; Matney, M.

    2017-01-01

    Comparing the natural meteorite flux at the Earth's surface to that of space debris, re-entering debris is 2 orders of magnitude less of a kinetic hazard at all but the very largest (and therefore rarest) sizes compared to natural impactors. Debris re-entries over several metric tonnes are roughly as frequent as natural impactors, but the survival fraction is expected to be much higher. Kinetic hazards from meteorites are very small, with only one recorded (indirect) injury reported. We expect fatalities to be even more rare, on the order of one person killed per several millennia. That several reports exist of small fragments/sand hitting people during meteorite falls is consistent with our prediction that this should occur every decade or so.

  2. Kinetic energy absorbing pad

    International Nuclear Information System (INIS)

    Bricmont, R.J.; Hamilton, P.A.; Ming Long Ting, R.

    1981-01-01

    Reactors, fuel processing plants etc incorporate pipes and conduits for fluids under high pressure. Fractures, particularly adjacent to conduit elbows, produce a jet of liquid which whips the broken conduit at an extremely high velocity. An enormous impact load would be applied to any stationary object in the conduit's path. The design of cellular, corrugated metal impact pads to absorb the kinetic energy of the high velocity conduits is given. (U.K.)

  3. Kinetic transport in crystals

    OpenAIRE

    Marklof, Jens

    2009-01-01

    One of the central challenges in kinetic theory is the derivation of macroscopic evolution equations--describing, for example, the dynamics of an electron gas--from the underlying fundamental microscopic laws of classical or quantum mechanics. An iconic mathematical model in this research area is the Lorentz gas, which describes an ensemble of non-interacting point particles in an infinite array of spherical scatterers. In the case of a disordered scatterer configuration, the classical result...

  4. Molecular aspects of hepatobiliary transport

    NARCIS (Netherlands)

    Muller, M; Jansen, PLM

    Generation of bile flow is a regulated, ATP-dependent process and depends on the coordinated action of a number of transporter proteins in the sinusoidal and canalicular domains of the hepatocyte. Dysfunction of any of these proteins leads to retention of substrates, with conjugated

  5. Calcite Dissolution Kinetics

    Science.gov (United States)

    Berelson, W.; Subhas, A.; Dong, S.; Naviaux, J.; Adkins, J. F.

    2016-12-01

    A geological buffer for high atmospheric CO2 concentrations is neutralization via reaction with CaCO3. We have been studying the dissolution kinetics of carbonate minerals using labeled 13C calcite and Picarro-based measurements of 13C enrichments in solution DIC. This methodology has greatly facilitated our investigation of dissolution kinetics as a function of water carbonate chemistry, temperature and pressure. One can adjust the saturation state Omega by changing the ion activity product (e.g. adjusting carbonate ion concentration), or by changing the solubility product (e.g. adjusting temperature or pressure). The canonical formulation of dissolution rate vs. omega has been refined (Subhas et al. 2015) and shows distinct non-linear behavior near equilibrium and rates in sea water of 1-3 e-6 g/cm2day at omega = 0.8. Carbonic anhydrase (CA), an enzyme that catalyzes the hydration of dissolved CO2 to carbonic acid, was shown (in concentrations 500x. This result points to the importance of carbonic acid in enhancing dissolution at low degrees of undersaturation. CA activity and abundance in nature must be considered regarding the role it plays in catalyzing dissolution. We also have been investigating the role of temperature on dissolution kinetics. An increase of 16C yields an order of magnitude increase in dissolution rate. Temperature (and P) also change Omega critical, the saturation state where dissolution rates change substantially. Increasing pressure (achieved in a pressure reaction chamber we built) also shifts Omega critical closer to equilibrium and small pressure increases have large impact on dissolution kinetics. Dissolution rates are enhanced by an order of magnitude for a change in pressure of 1500 psi relative to the dissolution rate achieved by water chemistry effects alone for an omega of 0.8. We've shown that the thermodynamic determination of saturation state does not adequately describe the kinetics of dissolution. The interplay of mineral

  6. Kinetics of tetrataenite disordering

    International Nuclear Information System (INIS)

    Dos Santos, E.; Gattacceca, J.; Rochette, P.; Fillion, G.; Scorzelli, R.B.

    2015-01-01

    Tetrataenite is a chemically ordered L1 0 -type Fe 50 Ni 50 alloy detected for the first time in 1977 by 57 Fe Mössbauer spectroscopy studies in iron meteorites. The thermal history of meteorites, in particular short thermal events like those associated to hypervelocity impacts, can be constrained by tracing the presence of tetrataenite or its disordering into taenite. The knowledge of the disordering kinetics of tetrataenite, that is associated with changes in its magnetic properties, is still very fragmentary so that the time–temperature history of these meteorites cannot be constrained in details. Furthermore, knowledge of disordering kinetics is important due to potential technological application of tetrataenite as a rare-earth free strong magnet. Thus, this work provides the first time–temperature data for disordering reaction of tetrataenite. We have shown that disordering is not an instantaneous process but is a kinetic limited reaction. It was shown that disordering may take place at any temperature above the order–disorder transition for L 10 superstructure phase (∼320 °C) when the appropriate time-scale is considered. This result means that the apparent Curie point for tetrataenite is not an absolute property in the sense that any estimate of this parameter should be referred to a given time-scale. - Highlights: • The first time–temperature data for tetrataenite disordering reaction is provided. • Previous works does not give a complete picture of tetrataenite disordering. • Apparent Curie temperature of tetrataenite should be referred to a time-scale. • Tetrataenite can be used as a probe to detect thermal/shock events recorded in meteorites

  7. Kinetics of tetrataenite disordering

    Energy Technology Data Exchange (ETDEWEB)

    Dos Santos, E., E-mail: edisanfi@cbpf.br [Centro Brasileiro de Pesquisas Físicas, Rio de Janeiro (Brazil); Gattacceca, J.; Rochette, P. [Centre Européen de Recherche et d’Enseignement des Géosciences de l’Environnement, UM34, CNRS/Aix-Marseille University, Aix-en-Provence (France); Fillion, G. [Laboratoire National des Champs Magnétiques Intenses (LNCMI), CNRS, UJF, 38042 Grenoble (France); Scorzelli, R.B. [Centro Brasileiro de Pesquisas Físicas, Rio de Janeiro (Brazil)

    2015-02-01

    Tetrataenite is a chemically ordered L1{sub 0}-type Fe{sub 50}Ni{sub 50} alloy detected for the first time in 1977 by {sup 57}Fe Mössbauer spectroscopy studies in iron meteorites. The thermal history of meteorites, in particular short thermal events like those associated to hypervelocity impacts, can be constrained by tracing the presence of tetrataenite or its disordering into taenite. The knowledge of the disordering kinetics of tetrataenite, that is associated with changes in its magnetic properties, is still very fragmentary so that the time–temperature history of these meteorites cannot be constrained in details. Furthermore, knowledge of disordering kinetics is important due to potential technological application of tetrataenite as a rare-earth free strong magnet. Thus, this work provides the first time–temperature data for disordering reaction of tetrataenite. We have shown that disordering is not an instantaneous process but is a kinetic limited reaction. It was shown that disordering may take place at any temperature above the order–disorder transition for L{sub 10} superstructure phase (∼320 °C) when the appropriate time-scale is considered. This result means that the apparent Curie point for tetrataenite is not an absolute property in the sense that any estimate of this parameter should be referred to a given time-scale. - Highlights: • The first time–temperature data for tetrataenite disordering reaction is provided. • Previous works does not give a complete picture of tetrataenite disordering. • Apparent Curie temperature of tetrataenite should be referred to a time-scale. • Tetrataenite can be used as a probe to detect thermal/shock events recorded in meteorites.

  8. Kinetics of stress fibers

    International Nuclear Information System (INIS)

    Stachowiak, Matthew R; O'Shaughnessy, Ben

    2008-01-01

    Stress fibers are contractile cytoskeletal structures, tensile actomyosin bundles which allow sensing and production of force, provide cells with adjustable rigidity and participate in various processes such as wound healing. The stress fiber is possibly the best characterized and most accessible multiprotein cellular contractile machine. Here we develop a quantitative model of the structure and relaxation kinetics of stress fibers. The principal experimentally known features are incorporated. The fiber has a periodic sarcomeric structure similar to muscle fibers with myosin motor proteins exerting contractile force by pulling on actin filaments. In addition the fiber contains the giant spring-like protein titin. Actin is continuously renewed by exchange with the cytosol leading to a turnover time of several minutes. In order that steady state be possible, turnover must be regulated. Our model invokes simple turnover and regulation mechanisms: actin association and dissociation occur at filament ends, while actin filament overlap above a certain threshold in the myosin-containing regions augments depolymerization rates. We use the model to study stress fiber relaxation kinetics after stimulation, as observed in a recent experimental study where some fiber regions were contractile and others expansive. We find that two distinct episodes ensue after stimulation: the turnover-overlap system relaxes rapidly in seconds, followed by the slow relaxation of sarcomere lengths in minutes. For parameter values as they have been characterized experimentally, we find the long time relaxation of sarcomere length is set by the rate at which actin filaments can grow or shrink in response to the forces exerted by the elastic and contractile elements. Consequently, the stress fiber relaxation time scales inversely with both titin spring constant and the intrinsic actin turnover rate. The model's predicted sarcomere velocities and contraction-expansion kinetics are in good

  9. Kinetics of stress fibers

    Energy Technology Data Exchange (ETDEWEB)

    Stachowiak, Matthew R; O' Shaughnessy, Ben [Department of Chemical Engineering, Columbia University, New York, NY 10027 (United States)], E-mail: bo8@columbia.edu

    2008-02-15

    Stress fibers are contractile cytoskeletal structures, tensile actomyosin bundles which allow sensing and production of force, provide cells with adjustable rigidity and participate in various processes such as wound healing. The stress fiber is possibly the best characterized and most accessible multiprotein cellular contractile machine. Here we develop a quantitative model of the structure and relaxation kinetics of stress fibers. The principal experimentally known features are incorporated. The fiber has a periodic sarcomeric structure similar to muscle fibers with myosin motor proteins exerting contractile force by pulling on actin filaments. In addition the fiber contains the giant spring-like protein titin. Actin is continuously renewed by exchange with the cytosol leading to a turnover time of several minutes. In order that steady state be possible, turnover must be regulated. Our model invokes simple turnover and regulation mechanisms: actin association and dissociation occur at filament ends, while actin filament overlap above a certain threshold in the myosin-containing regions augments depolymerization rates. We use the model to study stress fiber relaxation kinetics after stimulation, as observed in a recent experimental study where some fiber regions were contractile and others expansive. We find that two distinct episodes ensue after stimulation: the turnover-overlap system relaxes rapidly in seconds, followed by the slow relaxation of sarcomere lengths in minutes. For parameter values as they have been characterized experimentally, we find the long time relaxation of sarcomere length is set by the rate at which actin filaments can grow or shrink in response to the forces exerted by the elastic and contractile elements. Consequently, the stress fiber relaxation time scales inversely with both titin spring constant and the intrinsic actin turnover rate. The model's predicted sarcomere velocities and contraction-expansion kinetics are in good

  10. Kinetic theory of photophoresis

    International Nuclear Information System (INIS)

    Beresnev, S.A.; Chernyak, V.G.; Fomyagin, G.A.

    1988-01-01

    The force acting on an aerosol particle in one-sided illumination is calculated on the basis of solving a linearized gas-kinetic equation. A closed system of integral-moment equations describing photophoresis with arbitrary values of the Knudsen number and an arbitrary ratio of the particle and gas thermal conductivities is constructed. The possibility of arbitrary accommodation of the momentum and energy with interaction between the gas molecules and the particle surface is taken into account. The distribution of heat sources inside the radiation-absorbing particle is described by Mie theory. The results obtained are compared with the known theoretical and experimental data

  11. Chemical kinetics modeling

    Energy Technology Data Exchange (ETDEWEB)

    Westbrook, C.K.; Pitz, W.J. [Lawrence Livermore National Laboratory, CA (United States)

    1993-12-01

    This project emphasizes numerical modeling of chemical kinetics of combustion, including applications in both practical combustion systems and in controlled laboratory experiments. Elementary reaction rate parameters are combined into mechanisms which then describe the overall reaction of the fuels being studied. Detailed sensitivity analyses are used to identify those reaction rates and product species distributions to which the results are most sensitive and therefore warrant the greatest attention from other experimental and theoretical research programs. Experimental data from a variety of environments are combined together to validate the reaction mechanisms, including results from laminar flames, shock tubes, flow systems, detonations, and even internal combustion engines.

  12. Discussion on twenty-two hepatobiliary scintigraphs performed with technetium 99m-labelled N-(2,6 dimethylphenylcarbamoylmethyl) iminodiacetic acid (or HIDA-99mTc) at the Val-de-Grace Army Instruction Hospital

    International Nuclear Information System (INIS)

    Hoste, Philippe.

    1978-12-01

    Intraveinously injected technetium 99m-labelled N-(2,6 dimethyl-phenylcarbamoylmethyl) iminodiacetic acid, or HIDA-99mTc, is taken up by the hepatocytes and secreted in the bile, a fraction being normally eliminated by the kidneys. Isotopic examination with HIDA-99mTc gives valuable information on the morphology of the liver during the first minutes of the test, thus revealing the presence of parenchyma disease. In all observed cases of secondary hepatic localisations in particular the HIDA-99mTc images overlie those obtained with technetium colloids. By the examination it is also possible: - to establish the existence or otherwise of a functional vesicle, - to follow the path of the radiotracer along the bile duct. In short, HIDA-99mTc hepatobiliary scintigraphy is particularly useful for the study of hepatocyte uptake and bile elimination since it allows a continuous quantitative study of the liver-bile function under given physiological conditions [fr

  13. Sequential hepatobiliary scintigraphy of the patients with constitutional jaundice, ICG excretory defect disease and hepatocellular carcinoma with 99mTc-PI, 99mTc-HIDA and 99mTc-EHIDA

    International Nuclear Information System (INIS)

    Mitani, Tsuyoshi

    1987-01-01

    Sequential 2 min scintiphotos were obtained with a scintilation camera after intravenous injection of 3 mCi of 99m Tc-HIDA or 99m Tc-PI. Digital matrix images were simultaneously recorded with computer. Sequential samples for the blood clearance of 99m Tc-HIDA or 99m Tc-PI were obtained for 120 min following injection to the patient of constitutional hyperbilirubinemia and ICG excretory defect disease. In Dubin-Johnson syndrome, the hepatic uptake of 99m Tc-HIDA was faster or normal but the excretion was extremely slower than in normal cases. Both hepatic uptake and excretion of 99m Tc-PI were almost normal. In Rotor's disease, hepatic uptake of 99m Tc-HIDA or 99m Tc-PI was very poor, showing almost no hepatic images in all time. In Gilbert's disease and ICG excretory defect disease, hepatic uptake and excretion of 99m Tc-HIDA or 99m Tc-PI were within normal limit. From these results, Dubin-Johnson syndrome, Rotor's disease and Gilbert's disease show the different patterns between hepatic uptake and excretion of 99m Tc-HIDA and 99m Tc-PI hepatobiliary scintigraphy and these patterns contribute to the differential diagnosis of constitutional jaundice. The usefulness of hepatobiliary imaging with 99m Tc-EHIDA in diagnosis of hepatocellular carcinoma was studied in 15 patients with histologically verified HCC. In 15 patients, 3 patients (20 %) showed increased radioactivity with 99m Tc-EHIDA image, where liver scan with 99m Tc-Sn colloid showed filling defect. These results indicate that use of 99m Tc-EHIDA scan and 67 Ga-citrate imaging is useful for positive visualization of HCC. (author)

  14. Chemical kinetics of gas reactions

    CERN Document Server

    Kondrat'Ev, V N

    2013-01-01

    Chemical Kinetics of Gas Reactions explores the advances in gas kinetics and thermal, photochemical, electrical discharge, and radiation chemical reactions. This book is composed of 10 chapters, and begins with the presentation of general kinetic rules for simple and complex chemical reactions. The next chapters deal with the experimental methods for evaluating chemical reaction mechanisms and some theories of elementary chemical processes. These topics are followed by discussions on certain class of chemical reactions, including unimolecular, bimolecular, and termolecular reactions. The rema

  15. Kinetics of coal pyrolysis

    Energy Technology Data Exchange (ETDEWEB)

    Seery, D.J.; Freihaut, J.D.; Proscia, W.M. (United Technologies Research Center, East Hartford, CT (USA)); Howard, J.B.; Peters, W.; Hsu, J.; Hajaligol, M.; Sarofim, A. (Massachusetts Inst. of Tech., Cambridge, MA (USA)); Jenkins, R.; Mallin, J.; Espindola-Merin, B. (Pennsylvania State Univ., University Park, PA (USA)); Essenhigh, R.; Misra, M.K. (Ohio State Univ., Columbus, OH (USA))

    1989-07-01

    This report contains results of a coordinated, multi-laboratory investigation of coal devolatilization. Data is reported pertaining to the devolatilization for bituminous coals over three orders of magnitude in apparent heating rate (100 to 100,000 + {degree}C/sec), over two orders of magnitude in particle size (20 to 700 microns), final particle temperatures from 400 to 1600{degree}C, heat transfer modes ranging from convection to radiative, ambient pressure ranging from near vacuum to one atmosphere pressure. The heat transfer characteristics of the reactors are reported in detail. It is assumed the experimental results are to form the basis of a devolatilization data base. Empirical rate expressions are developed for each phase of devolatilization which, when coupled to an awareness of the heat transfer rate potential of a particular devolatilization reactor, indicate the kinetics emphasized by a particular system reactor plus coal sample. The analysis indicates the particular phase of devolatilization that will be emphasized by a particular reactor type and, thereby, the kinetic expressions appropriate to that devolatilization system. Engineering rate expressions are developed from the empirical rate expressions in the context of a fundamental understanding of coal devolatilization developed in the course of the investigation. 164 refs., 223 figs., 44 tabs.

  16. Adsorption analysis equilibria and kinetics

    CERN Document Server

    Do, Duong D

    1998-01-01

    This book covers topics of equilibria and kinetics of adsorption in porous media. Fundamental equilibria and kinetics are dealt with for homogeneous as well as heterogeneous particles. Five chapters of the book deal with equilibria and eight chapters deal with kinetics. Single component as well as multicomponent systems are discussed. In kinetics analysis, we deal with the various mass transport processes and their interactions inside a porous particle. Conventional approaches as well as the new approach using Maxwell-Stefan equations are presented. Various methods to measure diffusivity, such

  17. Kinetics of Social Contagion

    Science.gov (United States)

    Ruan, Zhongyuan; Iñiguez, Gerardo; Karsai, Márton; Kertész, János

    2015-11-01

    Diffusion of information, behavioral patterns or innovations follows diverse pathways depending on a number of conditions, including the structure of the underlying social network, the sensitivity to peer pressure and the influence of media. Here we study analytically and by simulations a general model that incorporates threshold mechanism capturing sensitivity to peer pressure, the effect of "immune" nodes who never adopt, and a perpetual flow of external information. While any constant, nonzero rate of dynamically introduced spontaneous adopters leads to global spreading, the kinetics by which the asymptotic state is approached shows rich behavior. In particular, we find that, as a function of the immune node density, there is a transition from fast to slow spreading governed by entirely different mechanisms. This transition happens below the percolation threshold of network fragmentation, and has its origin in the competition between cascading behavior induced by adopters and blocking due to immune nodes. This change is accompanied by a percolation transition of the induced clusters.

  18. Dimensional enhancement of kinetic energies

    DEFF Research Database (Denmark)

    Schleich, W.P.; Dahl, Jens Peder

    2002-01-01

    Simple thermodynamics considers kinetic energy to be an extensive variable which is proportional to the number N of particles. We present a quantum state of N noninteracting particles for which the kinetic energy increases quadratically with N. This enhancement effect is tied to the quantum...

  19. Evolution of Enzyme Kinetic Mechanisms.

    Science.gov (United States)

    Ulusu, Nuriye Nuray

    2015-06-01

    This review paper discusses the reciprocal kinetic behaviours of enzymes and the evolution of structure-function dichotomy. Kinetic mechanisms have evolved in response to alterations in ecological and metabolic conditions. The kinetic mechanisms of single-substrate mono-substrate enzyme reactions are easier to understand and much simpler than those of bi-bi substrate enzyme reactions. The increasing complexities of kinetic mechanisms, as well as the increasing number of enzyme subunits, can be used to shed light on the evolution of kinetic mechanisms. Enzymes with heterogeneous kinetic mechanisms attempt to achieve specific products to subsist. In many organisms, kinetic mechanisms have evolved to aid survival in response to changing environmental factors. Enzyme promiscuity is defined as adaptation to changing environmental conditions, such as the introduction of a toxin or a new carbon source. Enzyme promiscuity is defined as adaptation to changing environmental conditions, such as the introduction of a toxin or a new carbon source. Enzymes with broad substrate specificity and promiscuous properties are believed to be more evolved than single-substrate enzymes. This group of enzymes can adapt to changing environmental substrate conditions and adjust catalysing mechanisms according to the substrate's properties, and their kinetic mechanisms have evolved in response to substrate variability.

  20. Calcium kinetics in parathyroid disease

    International Nuclear Information System (INIS)

    Dymling, J.F.

    1964-01-01

    This paper reports a study of calcium kinetics in twelve cases of parathyroid disease. The data suggest that hyperparathyroidism usually causes increased bone turnover. The study of calcium kinetics may be a valuable tool in the differential diagnosis of primary hyperparathyroidism and in evaluating treatment of secondary hyperparathyroidism. The bone turnover in one case of hypoparathyroidism was extremely low. 1 fig., 1 tab

  1. Kinetics of Bio-Reactions

    DEFF Research Database (Denmark)

    Villadsen, John

    2015-01-01

    . The models can be used in mass balances for design of processes under process conditions not yet studied experimentally. The value of the predictive kinetic model depends on the quality of the experimental data on which the model is based, and well-founded kinetic models for enzyme reactions have...... a considerable predictive power. This is also true for cell reaction models, when the model is used in its proper context. The chapter first discusses the kinetics for enzymatically catalyzed reactions (“enzyme reactions”). The kinetics can be derived from a mechanistic model. Then, the chapter derives empirical......his chapter predicts the specific rates of reaction by means of a mathematical expression, the kinetics of the reaction. This expression can be derived through a mechanistic interpretation of an enzymatically catalyzed reaction, but it is essentially of empirical nature for cell reactions...

  2. Kinetic distance and kinetic maps from molecular dynamics simulation.

    Science.gov (United States)

    Noé, Frank; Clementi, Cecilia

    2015-10-13

    Characterizing macromolecular kinetics from molecular dynamics (MD) simulations requires a distance metric that can distinguish slowly interconverting states. Here, we build upon diffusion map theory and define a kinetic distance metric for irreducible Markov processes that quantifies how slowly molecular conformations interconvert. The kinetic distance can be computed given a model that approximates the eigenvalues and eigenvectors (reaction coordinates) of the MD Markov operator. Here, we employ the time-lagged independent component analysis (TICA). The TICA components can be scaled to provide a kinetic map in which the Euclidean distance corresponds to the kinetic distance. As a result, the question of how many TICA dimensions should be kept in a dimensionality reduction approach becomes obsolete, and one parameter less needs to be specified in the kinetic model construction. We demonstrate the approach using TICA and Markov state model (MSM) analyses for illustrative models, protein conformation dynamics in bovine pancreatic trypsin inhibitor and protein-inhibitor association in trypsin and benzamidine. We find that the total kinetic variance (TKV) is an excellent indicator of model quality and can be used to rank different input feature sets.

  3. The influence of bilirubin, alcohol and certain drugs on the kinetics of sup(99m)Tc-diethyl IDA (EHIDA) in humans

    International Nuclear Information System (INIS)

    Coenegracht, J.M.; Oei, T.L.; Breda Vriesman, P.J.C. van; Rijksuniversiteit Limburg, Maastricht

    1983-01-01

    On the basis of the mathematical analysis of sup(99m)Tc-EHIDA hepatobiliary time-activity curves of normal individuals two rate constants, one related to accumulation of radioactivity (uptake) and the other to excretion, were calculated indicating a two-compartmental model. By means of computerized fitting the rate constant of excretion (Ksub(b)), the time of maximum uptake (Tsub(max)) and the rate constant of uptake (Ksub(a)) were calculated. In severely jaundiced patients (serum bilirubin concentrations >140 μmol/l) a markedly decreased or absent uptake of sup(99m)Tc-EHIDA was observed. In moderately jaundiced patients a low Ksub(b) was invariably observed; in obstructive jaundice due to malignant disease - but not in jaundice of benign obstructive or hepatocellular origin - an increase in Ksub(a) was frequently present. This latter finding was not always present, however, and consequently kinetic studies do not unequivocally differentiate between jaundice of obstructive and hepatocellular origin. A markedly increased uptake (a high Ksub(a)) was noticed in alcoholics and patients taking phenobarbital and diphenylhydantoin possibly because of drug-induced membrane alterations. When the alcoholics developed hepatocellular injury the Ksub(a) converted to normal values. Thus, sup(99m)Tc-EHIDA kinetics may be useful in the follow-up of patients with established or suspected alcoholism by virtue of the fact that it appears to be a sensitive monitor of functional changes in hepatocyte plasma membrane properties. (orig.)

  4. Kinetics of Levoglucosenone Isomerization.

    Science.gov (United States)

    Krishna, Siddarth H; Walker, Theodore W; Dumesic, James A; Huber, George W

    2017-01-10

    We studied the acid-catalyzed isomerization of levoglucosenone (LGO) to 5-hydroxymethylfurfural (HMF) and developed a reaction kinetics model that describes the experimental data across a range of conditions (100-150 °C, 50-100 mm H 2 SO 4 , 50-150 mm LGO). LGO and its hydrated derivative exist in equilibrium under these reaction conditions. Thermal and catalytic degradation of HMF are the major sources of carbon loss. Within the range of conditions studied, higher temperatures and shorter reaction times favor the production of HMF. The yields of HMF and levulinic acid decrease monotonically as tetrahydrofuran is added to the aqueous solvent system, indicating that water plays a role in the LGO isomerization reaction. Initial-rate analyses show that HMF is produced solely from LGO rather than from the hydrated derivative of LGO. The results of this study are consistent with a mechanism for LGO isomerization that proceeds through hydration of the anhydro bridge, followed by ring rearrangement analogous to the isomerization of glucose to fructose. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. Kinetics of thyroid hormones

    International Nuclear Information System (INIS)

    Inada, Mitsuo; Nishikawa, Mitsushige; Naito, Kimikazu; Ishii, Hitoshi; Tanaka, Kiyoshi

    1980-01-01

    Kinetics of thyroid hormones were outlined, and recent progress in metabolism of these hormones was also described. Recently, not only T 4 and T 3 but also rT 3 , 3,3'-T 2 , 3',5'-T 2 , and 3,5-T 2 can be measured by RIA. To clarify metabolic pathways of these hormones, metabolic clearance rate and production rate of these hormones were calculated. As single-compartment analysis was insufficient to clarify disappearance curves of thyroid hormones in blood such as T 3 and T 2 of which metabolic speed was so fast, multi-compartment analysis or non-compartment analysis were also performed. Thyroid hormones seemed to be measured more precisely by constant infusion method. At the first step of T 4 metabolism, T 3 was formed by 5'-monodeiodination of T 4 , and rT 3 was formed by 5-monodeiodination of T 4 . As metabolic pathways of T 3 and rT 3 , conversion of them to 3,3'-T 2 or to 3',5'-T 2 and 3,5-T 2 was supposed. This subject will be an interesting research theme in future. (Tsunoda, M.)

  6. On the relationships between Michaelis-Menten kinetics, reverse Michaelis-Menten kinetics, Equilibrium Chemistry Approximation kinetics and quadratic kinetics

    Science.gov (United States)

    Tang, J. Y.

    2015-09-01

    The Michaelis-Menten kinetics and the reverse Michaelis-Menten kinetics are two popular mathematical formulations used in many land biogeochemical models to describe how microbes and plants would respond to changes in substrate abundance. However, the criteria of when to use which of the two are often ambiguous. Here I show that these two kinetics are special approximations to the Equilibrium Chemistry Approximation kinetics, which is the first order approximation to the quadratic kinetics that solves the equation of enzyme-substrate complex exactly for a single enzyme single substrate biogeochemical reaction with the law of mass action and the assumption of quasi-steady-state for the enzyme-substrate complex and that the product genesis from enzyme-substrate complex is much slower than the equilibration between enzyme-substrate complexes, substrates and enzymes. In particular, I showed that the derivation of the Michaelis-Menten kinetics does not consider the mass balance constraint of the substrate, and the reverse Michaelis-Menten kinetics does not consider the mass balance constraint of the enzyme, whereas both of these constraints are taken into account in the Equilibrium Chemistry Approximation kinetics. By benchmarking against predictions from the quadratic kinetics for a wide range of substrate and enzyme concentrations, the Michaelis-Menten kinetics was found to persistently under-predict the normalized sensitivity ∂ ln v / ∂ ln k2+ of the reaction velocity v with respect to the maximum product genesis rate k2+, persistently over-predict the normalized sensitivity ∂ ln v / ∂ ln k1+ of v with respect to the intrinsic substrate affinity k1+, persistently over-predict the normalized sensitivity ∂ ln v / ∂ ln [ E ]T of v with respect the total enzyme concentration [ E ]T and persistently under-predict the normalized sensitivity ∂ ln v / ∂ ln [ S ]T of v with respect to the total substrate concentration [ S ]T. Meanwhile, the reverse Michaelis

  7. Gas Kinetics of Traffic Jam

    Science.gov (United States)

    Nagatani, Takashi

    1997-04-01

    The kinetics of one-dimensional traffic flow is descibed in terms of Boltzmann-like gas kinetic equation. Paveri-Fontana's gas kinetic equation is modified to take into account the desired velocity depending on the car density. A discrete version of the gas kinetic equation is derived to numerically solve the equation. The velocity distributions are calculated by a numerical method. It is found that the traffic jam is formed in the congested traffic flow when the car density is higher than the critical value. The traffic jam propagates backward, its propagation velocity increases with the accerelation and the density within the jam decreases with increasing accerelation. It is shown that the velocity distributions change significantly before and after the traffic jam.

  8. Cell kinetics and therapeutic efficiency

    International Nuclear Information System (INIS)

    Andreeff, M.; Abenhardt, W.; Gruner, B.; Stoffner, D.; Mainz Univ.

    1976-01-01

    The study shows that cell kinetics effects correlate with the effects of cytostatic drugs in the tumour model investigated here. It should, however, be noted that even genetically related tumour cell types may react differently to the same cytostatic drug, and that the cell kinetics effects, due to the changes in the cell cycle, cannot be predicted but should be followed with a very fast method, e.g. sequential flan fluorescence cytophotometry, for optimal therapeutic results. (orig./GSE) [de

  9. Gyrocenter-gauge kinetic theory

    International Nuclear Information System (INIS)

    Qin, H.; Tang, W.M.; Lee, W.W.

    2000-01-01

    Gyrocenter-gauge kinetic theory is developed as an extension of the existing gyrokinetic theories. In essence, the formalism introduced here is a kinetic description of magnetized plasmas in the gyrocenter coordinates which is fully equivalent to the Vlasov-Maxwell system in the particle coordinates. In particular, provided the gyroradius is smaller than the scale-length of the magnetic field, it can treat high frequency range as well as the usual low frequency range normally associated with gyrokinetic approaches. A significant advantage of this formalism is that it enables the direct particle-in-cell simulations of compressional Alfven waves for MHD applications and of RF waves relevant to plasma heating in space and laboratory plasmas. The gyrocenter-gauge kinetic susceptibility for arbitrary wavelength and arbitrary frequency electromagnetic perturbations in a homogeneous magnetized plasma is shown to recover exactly the classical result obtained by integrating the Vlasov-Maxwell system in the particle coordinates. This demonstrates that all the waves supported by the Vlasov-Maxwell system can be studied using the gyrocenter-gauge kinetic model in the gyrocenter coordinates. This theoretical approach is so named to distinguish it from the existing gyrokinetic theory, which has been successfully developed and applied to many important low-frequency and long parallel wavelength problems, where the conventional meaning of gyrokinetic has been standardized. Besides the usual gyrokinetic distribution function, the gyrocenter-gauge kinetic theory emphasizes as well the gyrocenter-gauge distribution function, which sometimes contains all the physics of the problems being studied, and whose importance has not been realized previously. The gyrocenter-gauge distribution function enters Maxwell's equations through the pull-back transformation of the gyrocenter transformation, which depends on the perturbed fields. The efficacy of the gyrocenter-gauge kinetic approach is

  10. Sequential hepato-biliary scintigraphy of the patients with constitutional jaundices and ICG excretory defect disease with sup(99m)Tc-HIDA and sup(99m)Tc-PI

    International Nuclear Information System (INIS)

    Ueda, Hideo; Asahara, Akira; Hishinuma, Sanpei; Toogin, Masayuki; Takagi, Masao

    1979-01-01

    The hepato-biliary scintigraphy with sup(99m)Tc-HIDA and sup(99m)Tc-PI and the measurement of hepatic clearance have been studied on constitutional hyperbilirubinemia and ICG excretory defect disease. The results obtained are as follows: 1) In Dubin-Johnson's syndrome cases, the hepatic uptake of sup(99m)Tc-HIDA was faster, but the excretion was extremely slower than in normal cases. 2) Hepatic uptake and excretion of sup(99m)Tc-PI were both almost normal in Dubin-Johnson's syndrome. 3) In Rotor's disease, hepatic uptake of sup(99m)Tc-HIDA was very poor, showing almost no hepatic image. 4) In Gilbert's disease and ICG excretory defect disease, hepatic uptake and excretion of sup(99m)Tc-HIDA were both within normal limit. From these results it can be presumed that Dubin-Johnson's syndrome and Rotor's disease differ in morbid condition. Dubin-Johnson's syndrome, Rotor's disease and Gilbert's disease show the different patterns between hepatic uptake and excretion on sup(99m)Tc-HIDA hepatoscintigraphy and the patterns contribute to the differential diagnosis of constitutional jaundice. (author)

  11. Hypovascular hypointense nodules on hepatobiliary phase without T2 hyperintensity on gadoxetic acid-enhanced MR images in patients with chronic liver disease: long-term outcomes and risk factors for hypervascular transformation

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Yong Seek [Chonbuk National University Medical School and Hospital, Department of Radiology, Jeonju-si, Chonbuk (Korea, Republic of); Song, Ji Soo; Lee, Hyun Kyung; Han, Young Min [Chonbuk National University Medical School and Hospital, Department of Radiology, Jeonju-si, Chonbuk (Korea, Republic of); Chonbuk National University-Biomedical Research Institute of Chonbuk National University Hospital, Research Institute of Clinical Medicine, Chonbuk (Korea, Republic of)

    2016-10-15

    To evaluate the long-term outcomes and imaging features associated with hypervascularization of hypovascular nodules that show T2 iso-/hypointensity and hypointensity on hepatobiliary phase (HBP) of gadoxetic acid-enhanced magnetic resonance (MR) images in patients with chronic liver disease. Sixty patients and 114 nodules, which were hypovascular and iso-/hypointense on T2-weighted images and hypointense on HBP of gadoxetic acid-enhanced MRI, were included. We evaluated the effect of baseline clinical features, baseline MR features and growth rate on subsequent hypervascularization. Twenty-seven nodules in 21 patients transformed to hypervascular hepatocellular carcinoma (HCC). Using multivariate Cox analysis, T1 hyperintensity (hazard ratio [HR] = 2.69, P = 0.021), previous history of HCC (HR = 2.64, P = 0.021), and initial nodule size (HR = 1.09, P = 0.046) were identified to be associated with hypervascularization. The growth rate of nodules was a more powerful determinant of subsequent hypervascularization than baseline clinical and MR features. At long-term follow-up after >3 years, only one nodule with T1 isointensity showed hypervascularization. Careful follow-up or diagnostic procedures, such as biopsy, should be considered for up to 3 years after detection of hypointense nodules on HBP with T1 hyperintensity or a higher growth rate. (orig.)

  12. Correlation between hepatobiliary scintigraphy and surgery or postmortem examination findings in dogs and cats with extrahepatic biliary obstruction, partial obstruction, or patency of the biliary system: 18 cases (1995-2004).

    Science.gov (United States)

    Head, Laurie L; Daniel, Gregory B

    2005-11-15

    To evaluate the usefulness of serum biochemical variables and scintigraphic study results for differentiating between dogs and cats with complete extrahepatic biliary obstruction (EHO) and those with partial EHO or patent bile ducts. Retrospective case series. 17 dogs and 1 cat. Animals that underwent hepatobiliary scintigraphy and had either surgical or postmortem confirmation of the degree of bile duct patency were included. Scintigraphic images were evaluated and biliary tracts were classified as patent, partially obstructed but patent, or obstructed. Surgery or postmortem examination was considered the gold standard for diagnosis, and compared with those findings, sensitivity and specificity of scintigraphy were calculated. With absence of radioactivity in the intestinal tract as the diagnostic criterion for EHO, the sensitivity and specificity of scintigraphic diagnosis were both 83% when final images were acquired at 19 to 24 hours, compared with 100% and 33%, respectively, when 180 minutes was used as the cutoff time. Animals with partial biliary obstruction had less intestinal radioactivity that arrived later than that observed in animals with patent biliary tracts. Animals in which intestinal radioactivity has not been observed after the standard 3 to 4 hours should undergo additional scintigraphic imaging. Findings in animals with partial biliary obstruction include delayed arrival of radioactivity and less radioactivity in the intestine. Distinguishing between complete and partial biliary tract obstruction is important because animals with partial obstruction may respond favorably to medical management and should not be given an erroneous diagnosis of complete obstruction.

  13. Scintigraphic evaluation of duodenogastric reflux. Problems, pitfalls, and technical review.

    Science.gov (United States)

    Drane, W E; Karvelis, K; Johnson, D A; Silverman, E D

    1987-05-01

    Bile reflux has been implicated in the pathogenesis of gastritis, gastric ulcer, and esophagitis. Radionuclide techniques provide the only non-invasive method to detect duodenogastric reflux. To analyze the problems that occur with attempts at quantitation, 55 patients were prospectively evaluated (45 patients with reflux esophagitis or Barrett's esophagus and ten patients with clinical symptoms of bile reflux, four of whom had Bilroth II surgery) with Tc-99m DISIDA, using a fasting technique with gallbladder stimulation by sincalide. Visual duodenogastric reflux occurred in 16 of 55 patients. Overlap of small bowel with the stomach is the major problem for accurate quantitation and occurred in 20 of 55 patients (36%). Overlap of left lobe of the liver occurred in 40 of 55 patients (73%), but its contribution to gastric activity was slight and could be easily subtracted. Reflux was intermittent in six of the 16 positive studies (38%), and continuous computer acquisition is needed to detect its maximum value. Primarily because of the problem of small bowel overlap, scintigraphic evaluation of duodenogastric reflux is only, at best, semi-quantitative. A review of the technical variables used in this examination, as well as potential problems that can occur, is provided.

  14. Transformation kinetics for nucleus clusters

    International Nuclear Information System (INIS)

    Villa, Elena; Rios, Paulo R.

    2009-01-01

    A rigorous mathematical approach based on stochastic geometry concepts is presented to extend previous Johnson-Mehl, Avrami, Kolmogorov treatment of transformation kinetics to situations in which nuclei are not homogeneously located in space but are located in clusters. An exact analytical solution is presented here for the first time assuming that nucleation sites follow a Matern cluster process. The influence of Matern cluster process parameters on subsequent growth kinetics and the microstructural path are illustrated by means of numerical examples. Moreover, using the superposition principle, exact analytical solutions are also obtained when nucleation takes place by a combination of a Matern cluster process and an inhomogeneous Poisson point process. The new solutions presented here significantly increase the number of exactly solvable cases available to formal kinetics.

  15. Robustness Analysis of Kinetic Structures

    DEFF Research Database (Denmark)

    Kirkegaard, Poul Henning; Sørensen, John Dalsgaard

    2009-01-01

    The present paper considers robustness of kinetic structures. Robustness of structures has obtained a renewed interest due to a much more frequent use of advanced types of structures with limited redundancy and serious consequences in case of failure. Especially for these types of structural syst...... systems, it is of interest to investigate how robust the structures are, or what happens if a structural element is added to or removed from the original structure. The present paper discusses this issue for kinetic structures in architecture.......The present paper considers robustness of kinetic structures. Robustness of structures has obtained a renewed interest due to a much more frequent use of advanced types of structures with limited redundancy and serious consequences in case of failure. Especially for these types of structural...

  16. Kinetic theory and transport phenomena

    CERN Document Server

    Soto, Rodrigo

    2016-01-01

    This textbook presents kinetic theory, which is a systematic approach to describing nonequilibrium systems. The text is balanced between the fundamental concepts of kinetic theory (irreversibility, transport processes, separation of time scales, conservations, coarse graining, distribution functions, etc.) and the results and predictions of the theory, where the relevant properties of different systems are computed. The book is organised in thematic chapters where different paradigmatic systems are studied. The specific features of these systems are described, building and analysing the appropriate kinetic equations. Specifically, the book considers the classical transport of charges, the dynamics of classical gases, Brownian motion, plasmas, and self-gravitating systems, quantum gases, the electronic transport in solids and, finally, semiconductors. Besides these systems that are studied in detail, concepts are applied to some modern examples including the quark–gluon plasma, the motion of bacterial suspen...

  17. Chemical kinetics and reaction dynamics

    CERN Document Server

    Houston, Paul L

    2006-01-01

    This text teaches the principles underlying modern chemical kinetics in a clear, direct fashion, using several examples to enhance basic understanding. It features solutions to selected problems, with separate sections and appendices that cover more technical applications.Each chapter is self-contained and features an introduction that identifies its basic goals, their significance, and a general plan for their achievement. This text's important aims are to demonstrate that the basic kinetic principles are essential to the solution of modern chemical problems, and to show how the underlying qu

  18. Selected readings in chemical kinetics

    CERN Document Server

    Back, Margaret H

    2013-01-01

    Selected Readings in Chemical Kinetics covers excerpts from 12 papers in the field of general and gas-phase kinetics. The book discusses papers on the laws of connexion between the conditions of a chemical change and its amount; on the reaction velocity of the inversion of the cane sugar by acids; and the calculation in absolute measure of velocity constants and equilibrium constants in gaseous systems. The text then tackles papers on simple gas reactions; on the absolute rate of reactions in condensed phases; on the radiation theory of chemical action; and on the theory of unimolecular reacti

  19. Chemical kinetics and combustion modeling

    Energy Technology Data Exchange (ETDEWEB)

    Miller, J.A. [Sandia National Laboratories, Livermore, CA (United States)

    1993-12-01

    The goal of this program is to gain qualitative insight into how pollutants are formed in combustion systems and to develop quantitative mathematical models to predict their formation rates. The approach is an integrated one, combining low-pressure flame experiments, chemical kinetics modeling, theory, and kinetics experiments to gain as clear a picture as possible of the process in question. These efforts are focused on problems involved with the nitrogen chemistry of combustion systems and on the formation of soot and PAH in flames.

  20. Non-kinetic capabilities: complementing the kinetic prevalence to targeting

    NARCIS (Netherlands)

    Ducheine, P.

    2014-01-01

    Targeting is used in military doctrine to describe a military operational way, using (military) means to influence a target (or addressee) in order to achieve designated political and/or military goals. The four factors italicized are used to analyse non-kinetic targeting, complementing our

  1. Non-kinetic capabilities: complementing the kinetic prevalence to targeting

    NARCIS (Netherlands)

    Ducheine, P.A.L.; Ducheine, P.A.L.; Schmitt, M.N.; Osinga, F.P.B.

    2016-01-01

    Targeting is used in military doctrine to describe a military operational way, using (military) means to influence a target (or addressee) in order to achieve designated political and/or military goals. The four factors italicized are used to analyse non-kinetic targeting, thereby complementing our

  2. A compilation of reactor kinetics

    International Nuclear Information System (INIS)

    Paixao, Sergio Barros

    1996-01-01

    This work presents a brief chronological review of the development of the analytical and numerical solutions to the nuclear reactor kinetics equations. An emphasis has been set on a qualitative description of the problem rather than on specific mathematical issues. (author)

  3. Observation of Kinetic Plasma Jets

    OpenAIRE

    Tripathi, S. K. P.; Bellan, P. M.; Yun, G. S.

    2007-01-01

    Under certain conditions an intense kinetic plasma jet is observed to emerge from the apex of laboratory simulations of coronal plasma loops. Analytic and numerical models show that these jets result from a particle orbit instability in a helical magnetic field whereby magnetic forces radially eject rather than confine ions with sufficiently large counter-current axial velocity.

  4. Morphogenesis of Kinetic Reciprocal Frames

    DEFF Research Database (Denmark)

    Parigi, Dario; Sassone, Mario

    2011-01-01

    Kinetic structures in civil engineering and architecture gained considerable more attention in the very recent years as a practical solution to face time dependant performances. Realized projects are mostly bridges, retractable roofs, while in architecture the trend follows the category of intera......Kinetic structures in civil engineering and architecture gained considerable more attention in the very recent years as a practical solution to face time dependant performances. Realized projects are mostly bridges, retractable roofs, while in architecture the trend follows the category...... (RF) were studied in the past as a practical solution to span distances with shorter elements. Leonardo da Vinci discovered interesting RF patterns and studied three dimensional arch structures for bridges. RF are generally defined as structures that forms closed circuits of forces, and where elements...... joins in intermediate points. In the present paper we will describe a new subset of kinetic structures based on reciprocal frames topology and pin-slot constraint, a connection where a pin is constrained to move along a slot, and to rotate around its axis. The first step in obtaining a kinetic...

  5. Robustness Analysis of Kinetic Structures

    DEFF Research Database (Denmark)

    Kirkegaard, Poul Henning; Sørensen, John Dalsgaard

    2009-01-01

    Kinetic structures in architecture follows a new trend which is emerging in responsive architecture coined by Nicholas Negroponte when he proposed that architecture may benefit from the integration of computing power into built spaces and structures, and that better performing, more rational...

  6. Kinetic studies on leucite precursors

    Czech Academy of Sciences Publication Activity Database

    Mrázová, M.; Kloužková, A.; Kohoutková, Martina

    2009-01-01

    Roč. 7, č. 2 (2009), s. 205-210 ISSN 1895-1066 R&D Projects: GA MPO 2A-1TP1/063 Institutional research plan: CEZ:AV0Z40320502 Keywords : leucite * crystallization kinetics * hydrothermal Subject RIV: JH - Ceramics, Fire-Resistant Materials and Glass Impact factor: 1.065, year: 2009

  7. Solving Simple Kinetics without Integrals

    Science.gov (United States)

    de la Pen~a, Lisandro Herna´ndez

    2016-01-01

    The solution of simple kinetic equations is analyzed without referencing any topic from differential equations or integral calculus. Guided by the physical meaning of the rate equation, a systematic procedure is used to generate an approximate solution that converges uniformly to the exact solution in the case of zero, first, and second order…

  8. Some parameters of radionuclide kinetics

    International Nuclear Information System (INIS)

    Prokof'ev, O.N.; Smirnov, V.A.; Belen'kij, E.I.

    1978-01-01

    Numerical values of the rates of radionuclide absorption into, and elimination from, bovine organs were determined. Kinetic rate constants of radionuclides such as 89 Sr, 99 Mo, 131 I, 132 Tl, and 140 Be were calculated. The calculations were done for muscle, liver, and kidney

  9. Elements of plasma kinetic theory

    International Nuclear Information System (INIS)

    Guasp, J.

    1976-01-01

    The physical foundations of plasma kinetic equations are exposed inside a series of seminars on plasma and fusion physics. The Vlasov and collisional equations with its application range have been discussed. The momenta equations for the macroscopic magnitudes and the more usual approximations have been obtained: two fluid equations for cold and warm plasmas, magnetohydrodynamic equations and the double-adiabatic theory. (author)

  10. KINETIC SPECTROPHOTOMETRIC DETERMINATION OF SOME ...

    African Journals Online (AJOL)

    Preferred Customer

    proposed method was applied to the determination of the studied drugs in pharmaceutical formulations. KEY WORDS: Kinetic ... of fluoroquinolones either in pure forms, in dosage forms, or in biological fluids like ... chromatography [3-9], capillary zone electrophoresis [10, 11], electrochemistry [12-15], atomic absorption ...

  11. Thermodynamic basis for cluster kinetics

    DEFF Research Database (Denmark)

    Hu, Lina; Bian, Xiufang; Qin, Xubo

    2006-01-01

    Due to the inaccessibility of the supercooled region of marginal metallic glasses (MMGs) within the experimental time window, we study the cluster kinetics above the liquidus temperature, Tl, to acquire information on the fragility of the MMG systems. Thermodynamic basis for the stability...

  12. Kinetic investigation of wood pyrolysis

    Energy Technology Data Exchange (ETDEWEB)

    Thurner, F.; Mann, U.; Beck, S. R.

    1980-06-01

    The objective of this investigation was to determine the kinetics of the primary reactions of wood pyrolysis. A new experimental method was developed which enabled us to measure the rate of gas, tar, and char production while taking into account the temperature variations during the wood heating up. The experimental method developed did not require any sophisticated instruments. It facilitated the collection of gas, tar and residue (unreacted wood and char) as well as accurate measurement of the temperature inside the wood sample. Expressions relating the kinetic parameters to the measured variables were derived. The pyrolysis kinetics was investigated in the range of 300 to 400/sup 0/C at atmospheric pressure and under nitrogen atmosphere. Reaction temperature and mass fractions of gas, tar, and residue were measured as a function of time. Assuming first-order reactions, the kinetic parameters were determined using differential method. The measured activation energies of wood pyrolysis to gas, tar, and char were 88.6, 112.7, and 106.5 kJ/mole, respectively. These kinetic data were then used to predict the yield of the various pyrolysis products. It was found that the best prediction was obtained when an integral-mean temperature obtained from the temperature-time curve was used as reaction temperature. The pyrolysis products were analyzed to investigate the influence of the pyrolysis conditions on the composition. The gas consisted mainly of carbon dioxide, carbon monoxide, oxygen, and C/sub 3//sup +/-compounds. The gas composition depended on reaction time as well as reactor temperature. The tar analysis indicated that the tar consisted of about seven compounds. Its major compound was believed to be levoglucosan. Elemental analysis for the char showed that the carbon content increased with increasing temperature.

  13. Hepatobiliary alterations in massive biliary ascariasis: histopathological aspects of an autopsy case Lesões hepatobiliares em ascaridíase biliar maciça: aspectos histopatológicos em um caso de autópsia

    Directory of Open Access Journals (Sweden)

    Luiz Carlos da Costa Gayotto

    1990-04-01

    Full Text Available Hepatobiliary alterations found in an autopsy case of massive Biliary Ascariasis, are reported on histological grounds. Severe cholangitis was the main finding, but other changes were also detected, such as pyloric and intestinal metaplasia, hyperplasia of the epithelial lining, with intraductal papillomas and adenomatous proliferation. Remnants of the worm were observed tightly adhered to the epithelium, forming microscopic intrahepatic calculi. Mucopolysaccharides, especially acid, showed to be strongly positive on the luminal border, and in proliferated glands around the ducts. The authors discuss the similarity between such findings and Oriental Cholangiohepatitis, and suggest that inflammation and the presence of the parasitic remnants are responsible for the hyperplastic and metaplastic changes, similarly with what occurs in chlonorchiasis, fascioliasis and schistosomiasis.Os autores apresentam os aspectos histopatológicos encontrados no fígado de um caso de autópsia de Ascaridíase Biliar maciça. A intensa colangite foi o aspecto predominante, mas outras lesões também foram encontradas, tais como metaplasia pilórica e intestinal, hiperplasia epitelial com papilomas intraductais, e por vezes padrão adenomatoso. Restos do helminto foram encontrados fortemente aderidos ao epitélio, sendo intensa a positividade de mucopolissacárides, principalmente ácidos, na borda luminal do epitélio ductal e em glândulas proliferadas ao redor dos ductos. Os autores discutem a semelhança da Ascaridíase Biliar com a Colangio Hepatite Oriental, e sugerem que o processo inflamatório e a presença de restos do verme são responsáveis pelas alterações hiperplásicas e metaplásicas, analogamente ao que ocorre na clonorquíase, fasciolíase e esquistossomose.

  14. The value of paradoxical uptake of hepatocellular carcinoma on the hepatobiliary phase of gadoxetic acid-enhanced liver magnetic resonance imaging for the prediction of lipiodol uptake after transcatheter arterial chemoembolization

    International Nuclear Information System (INIS)

    Kim, Jeong Woo; Lee, Chang Hee; Park, Yang Shin; Seo, Tae Seok; Song, Myung Gyu; Kim, Ji Hoon; Kim, Kyeong Ah; Park, Cheol Min

    2017-01-01

    Highlights: • HCC para shows more frequent initial compact lipiodol uptake after TACE than HCC def . • HCC para demonstrates less frequent early local recurrence after TACE. • HCC para has larger mean size, lower AER, and more frequent capsule appearance. - Abstract: Purpose: To compare the response to transcatheter arterial chemoembolization (TACE) between hepatocellular carcinoma (HCC) with paradoxical uptake on the hepatobiliary phase (HBP) (HCC para ) and HCC with defect on the HBP (HCC def ), and to identify some imaging features that can differentiate between two groups. Materials and methods: Ninety-three HCCs from 54 patients who underwent gadoxetic acid-enhanced liver magnetic resonance imaging (MRI) prior to TACE were included. HCCs were classified into two groups according to the signal intensity (SI) on the HBP: HCC para and HCC def . Using post-TACE computed tomography (CT) as a reference standard, initial compact lipiodol uptake was assessed and compared between groups. The arterial enhancement ratio (AER), SI ratios of the arterial phase and HBP, and presence of the capsule appearance were compared between groups. After initial response, local tumor recurrence within 6 and 18 months was evaluated based on follow-up CT or MRI. Results: Fifteen HCC para and 78 HCC def were included. Compared to HCC def , HCC para showed more frequent initial compact lipiodol uptake (p = 0.009), larger mean size (p = 0.019), lower AER (p = 0.005), higher SI ratio of the HBP (p < 0.0001), and more frequent capsule appearance (p < 0.0001). Local tumor recurrence rate within 6 months was also significantly lower in HCC para than in HCC def (p = 0.008). Conclusion: Despite larger size and lower AER, HCC para showed more frequent initial compact lipiodol uptake and lower early local recurrence rate after TACE than did HCC def .

  15. Quantum kinetic Heisenberg models: a unique dynamics

    International Nuclear Information System (INIS)

    Timonen, J.; Pilling, D.J.; Bullough, R.K.

    1986-01-01

    We suggest that the dynamics Glauber embodied in his kinetic Ising model can be introduced similarly and in an apparently unique way, into the quantum statistical mechanics of the quantum-integrable models like the Heisenberg, sine-Gordon and Massive Thirring models. The latter may suggest an extension of the theory to unique kinetic Ising models in two dimensions. The kinetic repulsive bose gas which is studied in detail in the steady state seems to be a solvable kinetic model. (author)

  16. Holographic kinetic k-essence model

    Energy Technology Data Exchange (ETDEWEB)

    Cruz, Norman [Departamento de Fisica, Facultad de Ciencia, Universidad de Santiago de Chile, Casilla 307, Santiago (Chile)], E-mail: ncruz@lauca.usach.cl; Gonzalez-Diaz, Pedro F.; Rozas-Fernandez, Alberto [Colina de los Chopos, Instituto de Fisica Fundamental, Consejo Superior de Investigaciones Cientificas, Serrano 121, 28006 Madrid (Spain)], E-mail: a.rozas@cfmac.csic.es; Sanchez, Guillermo [Departamento de Matematica y Ciencia de la Computacion, Facultad de Ciencia, Universidad de Santiago de Chile, Casilla 307, Santiago (Chile)], E-mail: gsanchez@usach.cl

    2009-08-31

    We consider a connection between the holographic dark energy density and the kinetic k-essence energy density in a flat FRW universe. With the choice c{>=}1, the holographic dark energy can be described by a kinetic k-essence scalar field in a certain way. In this Letter we show this kinetic k-essential description of the holographic dark energy with c{>=}1 and reconstruct the kinetic k-essence function F(X)

  17. Kinetic modelling of enzymatic starch hydrolysis

    NARCIS (Netherlands)

    Bednarska, K.A.

    2015-01-01

    Kinetic modelling of enzymatic starch hydrolysis – a summary

    K.A. Bednarska

    The dissertation entitled ‘Kinetic modelling of enzymatic starch hydrolysis’ describes the enzymatic hydrolysis and kinetic modelling of liquefaction and saccharification of wheat starch.

  18. Comment on the Berkeley kinetic network model

    NARCIS (Netherlands)

    Doeksen, D.K.; Jongschaap, R.J.J.; Kamphuis, H.

    1985-01-01

    A kinetic model for the rheological behavior of polymeric systems, i.e. the Berkeley kinetic network model, is compared with a generalized transient-network model. It turns out that the Berkeley kinetic network model fits quite well in the framework of the transient-network model. From the point of

  19. Kinetics of yttrium oxide carbochlorination

    Energy Technology Data Exchange (ETDEWEB)

    Gaviria, J.P., E-mail: gaviriaj@cab.cnea.gov.ar [Division Cinetica Quimica - Complejo Tecnologico Pilcaniyeu - Centro Atomico Bariloche - Comision Nacional de Energia Atomica, Av. Bustillo km 9500 (8400), S.C. de Bariloche, Rio Negro (Argentina); Consejo Nacional de Investigaciones Cientificas y Tecnicas (Argentina); Fouga, G.G. [Division Cinetica Quimica - Complejo Tecnologico Pilcaniyeu - Centro Atomico Bariloche - Comision Nacional de Energia Atomica, Av. Bustillo km 9500 (8400), S.C. de Bariloche, Rio Negro (Argentina); Consejo Nacional de Investigaciones Cientificas y Tecnicas (Argentina); Bohe, A.E. [Division Cinetica Quimica - Complejo Tecnologico Pilcaniyeu - Centro Atomico Bariloche - Comision Nacional de Energia Atomica, Av. Bustillo km 9500 (8400), S.C. de Bariloche, Rio Negro (Argentina); Consejo Nacional de Investigaciones Cientificas y Tecnicas (Argentina); Centro Regional Universitario Bariloche - Universidad Nacional del Comahue (Argentina)

    2011-04-20

    Research highlights: {yields} Chlorination kinetics of Y{sub 2}O{sub 3}-C system was studied by thermogravimetry. {yields} The influence of carbon content, flow rate, sample mass and pCl{sub 2} were evaluated. {yields} Reaction proceeds through three successive stages until the formation of YCl{sub 3}(l). {yields}STAGE I is the formation of YOCl(s) and is under chemical control for T < 700 {sup o}C. {yields}STAGE I follows a nucleation and growth model. Kinetics parameters were obtained. - Abstract: The chlorination kinetics of the Y{sub 2}O{sub 3}-sucrose carbon system was studied by thermogravimetry. This work is a continuation of a previous one in which the reaction stages and the stoichiometry of each reaction have been determined. The influence of carbon content, total flow rate, sample initial mass and chlorine partial pressure was evaluated. The effect of carbon content on the reactive mixture was studied between 6.7 and 70% (carbon mass/total mass). The results showed that the reaction rate of each stage is strongly increased as the carbon content increases and the range of occurrence of the stages depends on the amount of carbon in the solid reactive mixture. The formation reaction of YOCl (STAGE I) is chemically controlled for temperatures lower than 700 {sup o}C with average effective activation energies of 165 {+-} 6 and 152 {+-} 7 kJ/mol for 8.7 and 16.7%C, respectively. The formation of the YOCl follows a nucleation and growth mechanism, with a combination of continuous nucleation and site saturation, and anisotropic growth controlled by diffusion. The kinetics of STAGE I can be expressed by the following global rate equation that includes the variables analyzed: (d{alpha})/(dt) =k{sub 0}Bexp(-(Ea)/(R{sub g}T) )pCl{sub 2}{l_brace}n(1-{alpha})[-ln(1-{alpha})]{r_brace}{sup (n-1)/n} where k{sub 0}B = 1.9 x 10{sup 4}, n = 1.20 for 8.7%C, and k{sub 0}B = 8.4 x 10{sup 3}, n = 1.14 for 16.7%C. STAGES II and III correspond to the YOCl carbochlorination to

  20. Kinetic approach to relativistic dissipation

    Science.gov (United States)

    Gabbana, A.; Mendoza, M.; Succi, S.; Tripiccione, R.

    2017-08-01

    Despite a long record of intense effort, the basic mechanisms by which dissipation emerges from the microscopic dynamics of a relativistic fluid still elude complete understanding. In particular, several details must still be finalized in the pathway from kinetic theory to hydrodynamics mainly in the derivation of the values of the transport coefficients. In this paper, we approach the problem by matching data from lattice-kinetic simulations with analytical predictions. Our numerical results provide neat evidence in favor of the Chapman-Enskog [The Mathematical Theory of Non-Uniform Gases, 3rd ed. (Cambridge University Press, Cambridge, U.K., 1970)] procedure as suggested by recent theoretical analyses along with qualitative hints at the basic reasons why the Chapman-Enskog expansion might be better suited than Grad's method [Commun. Pure Appl. Math. 2, 331 (1949), 10.1002/cpa.3160020403] to capture the emergence of dissipative effects in relativistic fluids.

  1. Kinetic theory of tearing instability

    International Nuclear Information System (INIS)

    Hazeltine, R.D.; Dobrott, D.; Wang, T.S.

    1975-01-01

    The guiding-center kinetic equation with Fokker-Planck collision term is used to study, in cylindrical geometry, a class of dissipative instabilities of which the classical tearing mode is an archetype. Variational solution of the kinetic equation obviates the use of an approximate Ohm's law or adiabatic assumption, as used in previous studies, and it provides a dispersive relation which is uniformly valid for any ratio of wave frequency to collision frequency. One result of using the rigorous collision operator is the prediction of a new instability. This instability, driven by the electron temperature gradient, is predicted to occur under the long mean-free path conditions of present tokamak experiments, and has significant features in common with the kink-like oscillations observed in such experiments

  2. Art Engineering and Kinetic Art

    Directory of Open Access Journals (Sweden)

    Barış Yılmaz

    2014-12-01

    Full Text Available Performing an art, either by painting or by sculpturing, requires to be interdisciplinary. When an artist creates his/her work of art, the process he/she realizes is supported by different engineering disciplines. Therefore, especially modern artists need to understand engineering science and this results in transforming artists into engineers. Opportunities provided by technology and science enable artists to expand his/her vision and to improve his/her works. Especially kinetic art has become an approach that combines art with engineering. Kinetic art, which is nourished with varied disciplines, is an excellent example to prove that art is interdisciplinary and to show the relationship between artist/art and engineering.

  3. Bumetanide kinetics in renal failure

    International Nuclear Information System (INIS)

    Pentikaeinen, P.J.P.; Pasternack, A.; Lampainen, E.; Neuvonen, P.J.; Penttilae, A.

    1985-01-01

    To study the effects of renal failure on bumetanide kinetics, the authors administered single intravenous doses of 1.0 mg/3.08 microCi 14 C-bumetanide to six healthy subjects and 22 patients with variable degrees of renal failure. The kinetics of 14 C-bumetanide and total 14 C were adequately described by a two-compartment open model in the control subjects and in the patients. The volume of the central compartment and the distribution t1/2 were of the same order in both groups, whereas the mean (+/- SE) volume at steady state was larger (22.1 +/- 1.6 and 16.9 +/- 1.0 L) and the elimination t1/2 was longer (1.9 +/- 0.2 and 1.4 +/- 0.1 hours) in patients with renal failure than in healthy controls. Bumetanide renal clearance was lower (10 +/- 3 and 90 +/- 13 ml/min) in patients than in subjects and correlated with creatinine clearance (r = 0.784) and log serum creatinine level (r = -0.843), whereas nonrenal clearance was significantly higher in the patients (153 +/- 14 and 99 +/- 6 ml/min). Bumetanide total plasma clearance did not significantly change. The non-protein-bound, free fraction of bumetanide was higher in patients and correlated with plasma albumin levels (r = -0.777). The kinetics of total 14 C showed similar but greater changes than those of 14C-bumetanide. Thus the most important changes in bumetanide kinetics in patients with renal failure are low renal clearance and a high free fraction, with a consequent increase in nonrenal clearance, volume of distribution, and elimination t1/2

  4. Kinetics of borided gear steels

    Indian Academy of Sciences (India)

    In this study, the case properties and diffusion kinetics of GS18NiMoCr36 (GS18), GS22NiMoCr56 (GS22) and GS32NiCrMo6.4 (GS32) gear steels borided in Ekabor-II powder were investigated by conducting a series of experiments at temperatures of 1123, 1173 and 1223 K for 2, 4 and 6 h. The boride layer was ...

  5. Overview on extraction kinetics of metal adducts

    International Nuclear Information System (INIS)

    Aly, H.F.; Daoud, J.A.

    1995-01-01

    A overview of extraction kinetics solvent extraction of metal adducts is given. A kinetic regime, diffusional regime, and mixed diffusional-kinetic regime are analysed. The practical applications of kinetics of solvent extraction processes in connection with technical processes and counter-current modelling is discussed. Kinetic studies are essential for the development of new processes and the knowledge of factors governing the mass transfer and mechanism of extraction of metal ions is of major importance in the design, operation, control and optimization of reactors in chemical industry. 23 refs

  6. Kinetic determination of morin nanoamounts

    Directory of Open Access Journals (Sweden)

    G. Z. MILETIC

    2004-06-01

    Full Text Available A kinetic-spectrophotometric method is proposed for the determination of morin. The method is based on the inhibition effect of morin on the oxidation of C6H5COONa by hydrogen peroxide in the presence of the complex Fe(II-AA(ascorbic acid, which acts as a catalyst. The concentration range for the determination of morin is one of the lowest achieved so far (a linear calibration graph was obtained for morin from 2.255–22.55 ng cm-3. The limit of detection of the method is 0.28 ng cm-3. The relative error ranges between 1.42 to 5.10 % for the given concentration interval. Kinetic equations are proposed for the investigated process. The effects of certain foreign ions upon the reaction rate were determined in order to assess the selectivity of the method. The major advantages of this kinetic-spectrophotometric assay are its sensitivity, selectivity, reproducibility, speed and simplicity.

  7. KINETIC ALGORITHMS FOR HARBOUR MANAGEMENT

    Directory of Open Access Journals (Sweden)

    C. M. Gold

    2012-07-01

    Full Text Available Modern harbour management for a busy port needs to resolve a variety of simultaneous problems. Harbour traffic may be busy and the waterways congested, both by the major shipping and by the attendant harbour tugs. The harbour channel may be narrow and tortuous, and rapidly changing tides may require frequent course adjustments. Navigation aids must be clearly specified and immediately identifiable, in order to permit safe passage for the vessels. This requires a GIS with attributes not easily available with traditional products. The GeoVS system is a kinetic GIS with full three-dimensional visualisation, so that ships, bathymetry and landscape may be viewed in a form that is immediately understandable to both harbour pilots and the harbour authority. The system is kinetic because the data structures used to preserve the topological relationships between ships, seafloor and coastline are able to be maintained on a real-time basis, taking account of ship movement recorded on the compulsory AIS (Automatic Information System beacons. Maintenance of this real-time topology allows for easy detection of potential collisions, as well as real-time bathymetric estimations, necessary to prevent ship grounding in highly tidal environments. The system, based on previous research into kinetic Voronoi diagrams, as well as development of a completely new graphical engine, is now in commercial production, where its advantages over simpler twodimensional models without automatic collision and grounding detection are becoming evident. Other applications are readily envisaged, and will be addressed in the near future.

  8. Oxidation kinetics of corium pool

    International Nuclear Information System (INIS)

    Sulatsky, A.A.; Smirnov, S.A.; Granovsky, V.S.; Khabensky, V.B.; Krushinov, E.V.; Vitol, S.A.; Kotova, S.Yu.; Fischer, M.; Hellmann, S.; Tromm, W.; Miassoedov, A.; Bottomley, D.; Piluso, P.; Barrachin, M.

    2013-01-01

    Highlights: • The analysis of experimental data on molten corium oxidation was been carried out. • The analysis has revealed the main factors influencing the oxidation kinetics. • The analysis was used for developing a qualitative analytical model. • The numerical modeling has confirmed the results of experimental data analysis. -- Abstract: Experimental, theoretical and numerical studies of oxidation kinetics of an open surface corium pool have been reported. The experiments have been carried out within OECD MASCA program and ISTC METCOR, METCOR-P and EVAN projects. It has been shown that the melt oxidation is controlled by an oxidant supply to the melt free surface from the atmosphere, not by the reducer supply from the melt. The project experiments have not detected any input of the zirconium oxidation kinetics into the process chemistry. The completed analysis puts forward a simple analytical model, which gives an explanation of the main features of melt oxidation process. The numerical modeling results are in good agreement with experimental data and theoretical considerations

  9. Kinetic Profile of Neuropeptide-Receptor Interactions.

    Science.gov (United States)

    Nederpelt, Indira; Bunnik, Julia; IJzerman, Adriaan P; Heitman, Laura H

    2016-12-01

    Currently, drug discovery focusses only on quantifying pharmacological parameters, sometimes including binding kinetics, of drug candidates. For a complete understanding of a drug's desired binding kinetics, the kinetics of both the target and its endogenous ligands should be considered. This is because the release and binding kinetics of endogenous ligands in addition to receptor internalization rates are significant contributors to drug-target interactions. Here, we discuss the kinetic profile of three neuropeptides and their receptors; gonadotropin-releasing hormone receptor (GnRHR), neuropeptide Y receptors, and corticotropin-releasing factor receptor 1 (CRF 1 R). These three examples provide new insights into the importance of kinetic profiles which could improve the understanding of desired drug-target binding kinetics and advance drug discovery for various neurological and psychiatric illnesses. Copyright © 2016 Elsevier Ltd. All rights reserved.

  10. A kinetics database and scripts for PHREEQC

    Science.gov (United States)

    Hu, B.; Zhang, Y.; Teng, Y.; Zhu, C.

    2017-12-01

    Kinetics of geochemical reactions has been increasingly used in numerical models to simulate coupled flow, mass transport, and chemical reactions. However, the kinetic data are scattered in the literature. To assemble a kinetic dataset for a modeling project is an intimidating task for most. In order to facilitate the application of kinetics in geochemical modeling, we assembled kinetics parameters into a database for the geochemical simulation program, PHREEQC (version 3.0). Kinetics data were collected from the literature. Our database includes kinetic data for over 70 minerals. The rate equations are also programmed into scripts with the Basic language. Using the new kinetic database, we simulated reaction path during the albite dissolution process using various rate equations in the literature. The simulation results with three different rate equations gave difference reaction paths at different time scale. Another application involves a coupled reactive transport model simulating the advancement of an acid plume in an acid mine drainage site associated with Bear Creek Uranium tailings pond. Geochemical reactions including calcite, gypsum, and illite were simulated with PHREEQC using the new kinetic database. The simulation results successfully demonstrated the utility of new kinetic database.

  11. The value of paradoxical uptake of hepatocellular carcinoma on the hepatobiliary phase of gadoxetic acid-enhanced liver magnetic resonance imaging for the prediction of lipiodol uptake after transcatheter arterial chemoembolization

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jeong Woo, E-mail: pridebio@naver.com [Department of Radiology, Korea University Guro Hospital, Korea University College of Medicine, Seoul (Korea, Republic of); Lee, Chang Hee, E-mail: chlee86@korea.ac.kr [Department of Radiology, Korea University Guro Hospital, Korea University College of Medicine, Seoul (Korea, Republic of); Park, Yang Shin, E-mail: pys797979@naver.com [Department of Radiology, Korea University Guro Hospital, Korea University College of Medicine, Seoul (Korea, Republic of); Seo, Tae Seok, E-mail: g1q1papa@korea.ac.kr [Department of Radiology, Korea University Guro Hospital, Korea University College of Medicine, Seoul (Korea, Republic of); Song, Myung Gyu, E-mail: acube808@naver.com [Department of Radiology, Korea University Guro Hospital, Korea University College of Medicine, Seoul (Korea, Republic of); Kim, Ji Hoon, E-mail: kjhhepar@naver.com [Department of Internal Medicine, Korea University Guro Hospital, Korea University College of Medicine, Seoul (Korea, Republic of); Kim, Kyeong Ah, E-mail: kahkim@korea.ac.kr [Department of Radiology, Korea University Guro Hospital, Korea University College of Medicine, Seoul (Korea, Republic of); Park, Cheol Min, E-mail: radpic@hanmail.net [Department of Radiology, Korea University Guro Hospital, Korea University College of Medicine, Seoul (Korea, Republic of)

    2017-04-15

    Highlights: • HCC{sub para} shows more frequent initial compact lipiodol uptake after TACE than HCC{sub def}. • HCC{sub para} demonstrates less frequent early local recurrence after TACE. • HCC{sub para} has larger mean size, lower AER, and more frequent capsule appearance. - Abstract: Purpose: To compare the response to transcatheter arterial chemoembolization (TACE) between hepatocellular carcinoma (HCC) with paradoxical uptake on the hepatobiliary phase (HBP) (HCC{sub para}) and HCC with defect on the HBP (HCC{sub def}), and to identify some imaging features that can differentiate between two groups. Materials and methods: Ninety-three HCCs from 54 patients who underwent gadoxetic acid-enhanced liver magnetic resonance imaging (MRI) prior to TACE were included. HCCs were classified into two groups according to the signal intensity (SI) on the HBP: HCC{sub para} and HCC{sub def}. Using post-TACE computed tomography (CT) as a reference standard, initial compact lipiodol uptake was assessed and compared between groups. The arterial enhancement ratio (AER), SI ratios of the arterial phase and HBP, and presence of the capsule appearance were compared between groups. After initial response, local tumor recurrence within 6 and 18 months was evaluated based on follow-up CT or MRI. Results: Fifteen HCC{sub para} and 78 HCC{sub def} were included. Compared to HCC{sub def}, HCC{sub para} showed more frequent initial compact lipiodol uptake (p = 0.009), larger mean size (p = 0.019), lower AER (p = 0.005), higher SI ratio of the HBP (p < 0.0001), and more frequent capsule appearance (p < 0.0001). Local tumor recurrence rate within 6 months was also significantly lower in HCC{sub para} than in HCC{sub def} (p = 0.008). Conclusion: Despite larger size and lower AER, HCC{sub para} showed more frequent initial compact lipiodol uptake and lower early local recurrence rate after TACE than did HCC{sub def}.

  12. Biodegradation kinetics at low concentrations (

    DEFF Research Database (Denmark)

    Toräng, Lars; Albrechtsen, Hans-Jørgen; Nyholm, Niels

    2000-01-01

    Aerobic biodegradation of 2,4-dichlorophenoxyacetic acid (2,4-D) was studied in groundwater added sediment fines. At concentrations at or below 1 mu g/L of 2,4-D degradation kinetic was of true first order without significant growth of specific degraders and with half-life for mineralization...... in the order of 200 days. Higher concentrations of 2,4-D resulted in a grossly overestimate of the actual degradation rate for concentrations characteristic for Danish found in groundwater....

  13. Kinetics of heterogeneous catalytic reactions

    CERN Document Server

    Boudart, Michel

    2014-01-01

    This book is a critical account of the principles of the kinetics of heterogeneous catalytic reactions in the light of recent developments in surface science and catalysis science. Originally published in 1984. The Princeton Legacy Library uses the latest print-on-demand technology to again make available previously out-of-print books from the distinguished backlist of Princeton University Press. These paperback editions preserve the original texts of these important books while presenting them in durable paperback editions. The goal of the Princeton Legacy Library is to vastly increase acc

  14. Free-Form Kinetic Reciprocal System

    DEFF Research Database (Denmark)

    Parigi, Dario; Sassone, Mario

    2011-01-01

    Kinetic Reciprocal System (KRS) are innovative moveable structures based on the principle of reciprocity [1] with internal pin-slot constraints [2]. The analysis of KRS kinematic and static determinacy is developed through the construction of kinematic matrices, accordingly with [3...... of the required kinetic behaviour and its validity has been tested on physical models. A set of case studies and possible applications are described, focusing on the morphologic variety of results and on the efficiency of the kinetic performance....

  15. Conformational kinetics of aliphatic tails

    Science.gov (United States)

    Ferrarini, Alberta; Moro, Giorgio; Nordio, Pier Luigi

    The master equation describing the random walk between sites identified with the stable conformers of a chain molecule, represents the extension to the time domain of the Rotational Isomeric State model. The asymptotic analysis of the multidimensional diffusion equation in the continuous torsional variables subjected to the configurational potential, provides a rigorous justification for the discrete models, and it supplies, without resorting to phenomenological parameters, molecular definitions of the kinetic rates for the conformational transitions occurring at each segment of the chain. The coupling between the torsional variables is fully taken into account, giving rise to cooperative effects. A complete calculation of the specific correlation functions which describe the time evolution of the angular functions probed by N.M.R. and dielectric relaxation measurements, has been performed for alkyl chains attached to a massive core. The resulting behaviour has been compared with the decay of trans and gauche populations of specific bonds, expressed in terms of suitable correlation functions whose time integrals lead quite naturally to the definition of effective kinetic constants for the conformational transitions.

  16. Kinetic Profiles in NSTX Plasmas

    Energy Technology Data Exchange (ETDEWEB)

    R.E. Bell; B.P. LeBlanc; C. Bourdelle; D.R. Ernst; E.D. Fredrickson; D.A. Gates; J.C. Hosea; D.W. Johnson; S.M. Kaye; R. Maingi; S. Medley; J.E. Menard; D. Mueller; M. Ono; F. Paoletti; M. Peng; S.A. Sabbagh; D. Stutman; D.W. Swain; E.J. Synakowski; and J.R. Wilson

    2001-07-10

    The National Spherical Torus Experiment (NSTX) is a low aspect ratio (R/a approximately 1.3) device with auxiliary heating from neutral-beam injection (NBI) and high-harmonic fast-wave heating (HHFW). Typical NSTX parameters are R(subscript ''0'') = 85 cm, a = 67 cm, I(subscript ''p'') = 0.7-1.4 MA, B(subscript ''phi'') = 0.25-0.45 T. Three co-directed deuterium neutral-beam sources have injected P(subscript ''NB'') less than or equal to 4.7 MW. HHFW plasmas typically have delivered P(subscript ''RF'') less than or equal to 3 MW. Important to the understanding of NSTX confinement are the new kinetic profile diagnostics: a multi-pulse Thomson scattering system (MPTS) and a charge-exchange recombination spectroscopy (CHERS) system. The MPTS diagnostic currently measures electron density and temperature profiles at 30 Hz at ten spatial locations. The CHERS system has recently become available to measure carbon ion temperature and toroidal flow at 17 radial positions spanning the outer half of the minor radius with 20 msec time resolution during NBI. Experiments conducted during the last year have produced a wide range of kinetic profiles in NSTX. Some interesting examples are presented below.

  17. Combustion kinetics and reaction pathways

    Energy Technology Data Exchange (ETDEWEB)

    Klemm, R.B.; Sutherland, J.W. [Brookhaven National Laboratory, Upton, NY (United States)

    1993-12-01

    This project is focused on the fundamental chemistry of combustion. The overall objectives are to determine rate constants for elementary reactions and to elucidate the pathways of multichannel reactions. A multitechnique approach that features three independent experiments provides unique capabilities in performing reliable kinetic measurements over an exceptionally wide range in temperature, 300 to 2500 K. Recent kinetic work has focused on experimental studies and theoretical calculations of the methane dissociation system (CH{sub 4} + Ar {yields} CH{sub 3} + H + Ar and H + CH{sub 4} {yields} CH{sub 3} + H{sub 2}). Additionally, a discharge flow-photoionization mass spectrometer (DF-PIMS) experiment is used to determine branching fractions for multichannel reactions and to measure ionization thresholds of free radicals. Thus, these photoionization experiments generate data that are relevant to both reaction pathways studies (reaction dynamics) and fundamental thermochemical research. Two distinct advantages of performing PIMS with high intensity, tunable vacuum ultraviolet light at the National Synchrotron Light Source are high detection sensitivity and exceptional selectivity in monitoring radical species.

  18. MBS Analysis Of Kinetic Structures Using ADAMS

    DEFF Research Database (Denmark)

    Kirkegaard, Poul Henning; Nielsen, Søren R.K.

    2009-01-01

    The present paper considers multibody system (MBS) analysis of kinetic structures using the software package ADAMS. Deployable, foldable, expandable and reconfigurable kinetic structures can provide a change in the geometric morphology of the envelope by contributing to making it adaptable to e......-called multibody system (MBS) formalism. The present paper considers MBS modeling of kinetic architectural structures using the software packages ADAMS. As a result, it is found that symbolic MBS simulation tools facilitate a useful evaluation environment for MBS users during a design phase of responsive kinetic...

  19. Drug-Target Kinetics in Drug Discovery.

    Science.gov (United States)

    Tonge, Peter J

    2018-01-17

    The development of therapies for the treatment of neurological cancer faces a number of major challenges including the synthesis of small molecule agents that can penetrate the blood-brain barrier (BBB). Given the likelihood that in many cases drug exposure will be lower in the CNS than in systemic circulation, it follows that strategies should be employed that can sustain target engagement at low drug concentration. Time dependent target occupancy is a function of both the drug and target concentration as well as the thermodynamic and kinetic parameters that describe the binding reaction coordinate, and sustained target occupancy can be achieved through structural modifications that increase target (re)binding and/or that decrease the rate of drug dissociation. The discovery and deployment of compounds with optimized kinetic effects requires information on the structure-kinetic relationships that modulate the kinetics of binding, and the molecular factors that control the translation of drug-target kinetics to time-dependent drug activity in the disease state. This Review first introduces the potential benefits of drug-target kinetics, such as the ability to delineate both thermodynamic and kinetic selectivity, and then describes factors, such as target vulnerability, that impact the utility of kinetic selectivity. The Review concludes with a description of a mechanistic PK/PD model that integrates drug-target kinetics into predictions of drug activity.

  20. Kinetic effects in dynamic wetting

    Science.gov (United States)

    Sprittles, James

    2017-11-01

    The maximum speed at which a liquid can wet a solid is limited by the need to displace gas lubrication films in front of the moving contact line. The characteristic height of these films is often comparable to the mean free path in the gas so that hydrodynamic models do not adequately describe the flow physics. In this talk, I will develop a model which incorporates kinetic effects in the gas, via the Boltzmann equation, and can predict experimentally-observed increases in the maximum speed of wetting when (a) the liquid's viscosity is varied, (b) the ambient gas pressure is reduced or (c) the meniscus is confined. This work was supported by the Leverhulme Trust (Research Project Grant) and the Engineering & Physical Sciences Research Council (Grant EP/N016602/1).

  1. Nuclear reactor kinetics and control

    International Nuclear Information System (INIS)

    Lewins, J.

    1978-01-01

    A consistent, integrated account of modern developments in the study of nuclear reactor kinetics and the problem of their efficient and safe control. It aims to prepare the student for advanced study and research or practical work in the field. Special features include treatments of noise theory, reliability theory and safety related studies. It covers all aspects of the operation and control of nuclear reactors, power and research and is complete in providing physical data methods of calculation and solution including questions of equipment reliability. The work uses illustrations of the main types of reactors in use in the UK, USA and Europe. Each chapter contains problems and worked examples suitable for course work and study. The subject is covered in chapters, entitled: introductory review; neutron and precursor equations; elementary solutions at low power; linear reactor process dynamics with feedback; power reactor control systems; fluctuations and reactor noise; safety and reliability; nonlinear systems (safety and control); analogue computing. (author)

  2. Method of molybdenum kinetic determination

    International Nuclear Information System (INIS)

    Krejngol'd, S.U.; Dzotsenidze, N.E.; Ruseishviyai, T.G.; Nelen', I.M.

    1980-01-01

    The method molybdenum kinetic determination according to oxidation of pyrogallol with bromate in the medium of 0.05-0.15 M perchloric or sulphuric acids is presented. 1 mg of Ni, Co, Mn, Mg, Zn, Cr(3); 100 μg of Ca, Al, Cu, 10 μg of Cr(4), W; 10 μg of Fe in the presence of 22x10 - 4 M solution of EDTA, as well as 10 - 4 M solutions of chlorides and fluorides, 10 - 5 M solutions of bromides do not interfere with molybdenum determination using the given method. The method is rather simple, it takes 30 min to carry out the analysis. Determination limit of molybdenum constitutes 0.01 μg/ml

  3. Dissolution Kinetics of Alumina Calcine

    Energy Technology Data Exchange (ETDEWEB)

    Batcheller, Thomas Aquinas

    2001-09-01

    Dissolution kinetics of alumina type non-radioactive calcine was investigated as part of ongoing research that addresses permanent disposal of Idaho High Level Waste (HLW). Calcine waste was produced from the processing of nuclear fuel at the Idaho Nuclear Technology and Engineering Center (INTEC). Acidic radioactive raffinates were solidified at ~500°C in a fluidized bed reactor to form the dry granular calcine material. Several Waste Management alternatives for the calcine are presented in the Idaho High Level Waste Draft EIS. The Separations Alternative addresses the processing of the calcine so that the HLW is ready for removal to a national geological repository by the year 2035. Calcine dissolution is the key front-end unit operation for the separations alternative.

  4. Analysis of kinetic reaction mechanisms

    CERN Document Server

    Turányi, Tamás

    2014-01-01

    Chemical processes in many fields of science and technology, including combustion, atmospheric chemistry, environmental modelling, process engineering, and systems biology, can be described by detailed reaction mechanisms consisting of numerous reaction steps. This book describes methods for the analysis of reaction mechanisms that are applicable in all these fields. Topics addressed include: how sensitivity and uncertainty analyses allow the calculation of the overall uncertainty of simulation results and the identification of the most important input parameters, the ways in which mechanisms can be reduced without losing important kinetic and dynamic detail, and the application of reduced models for more accurate engineering optimizations. This monograph is invaluable for researchers and engineers dealing with detailed reaction mechanisms, but is also useful for graduate students of related courses in chemistry, mechanical engineering, energy and environmental science and biology.

  5. Kinetics of irradiated liquid hydrogen

    International Nuclear Information System (INIS)

    Iverson, E.B.; Carpenter, J.M.

    2004-01-01

    We present a model for the kinetics of irradiated liquid hydrogen, as appropriate to a spallation neutron source environment. This model indicates that the ortho-para distribution in an irradiated volume of liquid hydrogen may be significantly different from the thermodynamically equilibrated distribution, resulting in significantly changed neutronic and operational performance for practical liquid hydrogen moderators. Numerical experimentation with the model indicates that neither the pulsed nature of a pulsed source nor the cyclic nature of a flowing liquid hydrogen loop significantly impacts the ortho-para distribution. In developing this model, we have learned that many proposed methods for measuring the ortho-para distribution in an operating moderator system may have potential difficulties, complicating bench-marking efforts. (orig.)

  6. NESTLE: A nodal kinetics code

    International Nuclear Information System (INIS)

    Al-Chalabi, R.M.; Turinsky, P.J.; Faure, F.-X.; Sarsour, H.N.; Engrand, P.R.

    1993-01-01

    The NESTLE nodal kinetics code has been developed for utilization as a stand-alone code for steady-state and transient reactor neutronic analysis and for incorporation into system transient codes, such as TRAC and RELAP. The latter is desirable to increase the simulation fidelity over that obtained from currently employed zero- and one-dimensional neutronic models and now feasible due to advances in computer performance and efficiency of nodal methods. As a stand-alone code, requirements are that it operate on a range of computing platforms from memory-limited personal computers (PCs) to supercomputers with vector processors. This paper summarizes the features of NESTLE that reflect the utilization and requirements just noted

  7. Nanoparticle shape, thermodynamics and kinetics

    International Nuclear Information System (INIS)

    Marks, L D; Peng, L

    2016-01-01

    Nanoparticles can be beautiful, as in stained glass windows, or they can be ugly as in wear and corrosion debris from implants. We estimate that there will be about 70 000 papers in 2015 with nanoparticles as a keyword, but only one in thirteen uses the nanoparticle shape as an additional keyword and research focus, and only one in two hundred has thermodynamics. Methods for synthesizing nanoparticles have exploded over the last decade, but our understanding of how and why they take their forms has not progressed as fast. This topical review attempts to take a critical snapshot of the current understanding, focusing more on methods to predict than a purely synthetic or descriptive approach. We look at models and themes which are largely independent of the exact synthetic method whether it is deposition, gas-phase condensation, solution based or hydrothermal synthesis. Elements are old dating back to the beginning of the 20th century—some of the pioneering models developed then are still relevant today. Others are newer, a merging of older concepts such as kinetic-Wulff constructions with methods to understand minimum energy shapes for particles with twins. Overall we find that while there are still many unknowns, the broad framework of understanding and predicting the structure of nanoparticles via diverse Wulff constructions, either thermodynamic, local minima or kinetic has been exceedingly successful. However, the field is still developing and there remain many unknowns and new avenues for research, a few of these being suggested towards the end of the review. (topical review)

  8. Nanoparticle shape, thermodynamics and kinetics

    Science.gov (United States)

    Marks, L. D.; Peng, L.

    2016-02-01

    Nanoparticles can be beautiful, as in stained glass windows, or they can be ugly as in wear and corrosion debris from implants. We estimate that there will be about 70 000 papers in 2015 with nanoparticles as a keyword, but only one in thirteen uses the nanoparticle shape as an additional keyword and research focus, and only one in two hundred has thermodynamics. Methods for synthesizing nanoparticles have exploded over the last decade, but our understanding of how and why they take their forms has not progressed as fast. This topical review attempts to take a critical snapshot of the current understanding, focusing more on methods to predict than a purely synthetic or descriptive approach. We look at models and themes which are largely independent of the exact synthetic method whether it is deposition, gas-phase condensation, solution based or hydrothermal synthesis. Elements are old dating back to the beginning of the 20th century—some of the pioneering models developed then are still relevant today. Others are newer, a merging of older concepts such as kinetic-Wulff constructions with methods to understand minimum energy shapes for particles with twins. Overall we find that while there are still many unknowns, the broad framework of understanding and predicting the structure of nanoparticles via diverse Wulff constructions, either thermodynamic, local minima or kinetic has been exceedingly successful. However, the field is still developing and there remain many unknowns and new avenues for research, a few of these being suggested towards the end of the review.

  9. Kinetics model for lutate dosimetry

    International Nuclear Information System (INIS)

    Lima, M.F.; Mesquita, C.H.

    2013-01-01

    The use of compartmental analysis to predict the behavior of drugs in the organism is considered the better option among numerous methods employed in pharmacodynamics. A six compartments model was developed to determinate the kinetic constants of 177Lu-DOTATATO biodistribution using data from one published study with 67 patients treated by PRRT (Peptide receptor radionuclide therapy) and followed by CT during 68,25 hours. The compartmental analysis was made using the software AnaComp®. The influence of the time pos-injection over the dose assessment was studied taking into account the renal excretion management by aminoacid coinfusion, whose direct effects persist in the first day. The biodistribution curve was split in five sectors: 0-0.25h; 0-3.25h; 3.25-24.25h; 24.25-68.25h and 3.25-68.25h. After the examination of that influence, the study was concentrated in separate the biodistribution curve in two phases. Phase 1: governed by uptake from the blood, considering the time pos-injection until 3.25h and phase 2: governed by renal excretion, considering the time pos-injection from 3.25h to 68.25h. The model considered the organs and tissues superposition in the CT image acquisition by sampling parameters as the contribution of the the activity concentration in blood and relation between the sizes of the whole body and measured organs. The kinetic constants obtained from each phase (1 and 2) were used in dose assessment to patients in 26 organs and tissues described by MIRD. Dosimetry results were in agreement with the available results from literature, restrict to whole body, kidneys, bone marrow, spleen and liver. The advantage of the proposed model is the compartmental method quickness and power to estimate dose in organs and tissues, including tumor that, in the most part, were not discriminate by voxels of phantoms built using CT images. (author)

  10. Hepatobiliary Fascioliasis: Clinical and Radiological Features

    Directory of Open Access Journals (Sweden)

    K Aghazade

    2007-08-01

    Full Text Available Fascioliasis is a worldwide but unevenly distributed zoonosis caused by the trematode Fasciola hepatica that infects do­mesti­cated herbivores. Fasciolosis also occurs accidentally in humans by ingestion of metacercaria-laden freshwater or water plants. Human infections are common in developing countries and are not rare in Europe. The clinical course has been con­ventionally described in two phases: an acute phase of hepatic parenchymal invasion of an immature worm larva (parenchy­mal phase and a stationary phase after residence in the bile duct and production of eggs (ductal phase. We report a 34 years old woman from Ilam, western Iran with hepatic disorder, RUQ pain, and jaundice. The diagnosis was made by sonography, CT scan and serologic studies. Serologic exam (ELISA was positive & CT findings were compatible with fascioliasis.

  11. Role of laparoscopy in hepatobiliary malignancies

    Directory of Open Access Journals (Sweden)

    Prabhu Arumugam

    2016-01-01

    Full Text Available The many benefits of laparoscopy, including smaller incision, reduced length of hospital stay and more rapid return to normal function, have seen its popularity grow in recent years. With concurrent improvements in non-surgical cancer management the importance of accurate staging is becoming increasingly important. There are two main applications of laparoscopic surgery in managing hepato-pancreatico-biliary (HPB malignancy: accurate staging of disease and resection. We aim to summarize the use of laparoscopy in these contexts. The role of staging laparoscopy has become routine in certain cancers, in particular T[2] staged, locally advanced gastric cancer, hilar cholangiocarcinoma and non-Hodgkin's lymphoma. For other cancers, in particular colorectal, laparoscopy has now become the gold standard management for resection such that there is no role for stand-alone staging laparoscopy. In HPB cancers, although staging laparoscopy may play a role, with ever improving radiology, its role remains controversial.

  12. Role of laparoscopy in hepatobiliary malignancies.

    Science.gov (United States)

    Arumugam, Prabhu; Balarajah, Vickna; Watt, Jennifer; Abraham, Ajit T; Bhattacharya, Satyajit; Kocher, Hemant M

    2016-04-01

    The many benefits of laparoscopy, including smaller incision, reduced length of hospital stay and more rapid return to normal function, have seen its popularity grow in recent years. With concurrent improvements in non-surgical cancer management the importance of accurate staging is becoming increasingly important. There are two main applications of laparoscopic surgery in managing hepato-pancreatico-biliary (HPB) malignancy: accurate staging of disease and resection. We aim to summarize the use of laparoscopy in these contexts. The role of staging laparoscopy has become routine in certain cancers, in particular T[2] staged, locally advanced gastric cancer, hilar cholangiocarcinoma and non-Hodgkin's lymphoma. For other cancers, in particular colorectal, laparoscopy has now become the gold standard management for resection such that there is no role for stand-alone staging laparoscopy. In HPB cancers, although staging laparoscopy may play a role, with ever improving radiology, its role remains controversial.

  13. Hepatobiliary rhabdomyosarcoma in children: diagnostic radiology

    International Nuclear Information System (INIS)

    Roebuck, D.J.; Yang Weitse; Lam, W.W.M.; Stanley, P.

    1998-01-01

    Rhabdomyosarcoma (RMS) occurs infrequently in the liver and biliary tree. Although the radiological diagnosis may be simple when the tumour involves the extrahepatic bile ducts, no specific imaging features are known for hepatic RMS. We present four cases and discuss the role of diagnostic radiology in the management of this tumour. (orig.)

  14. Kinetic spectrophotometric determination of some fluoroquinolone ...

    African Journals Online (AJOL)

    A simple and sensitive kinetic spectrophotometric method was developed for the determination of some fluoroquinolonea antibiotics; gemifloxacin mesylate, moxifloxacin hydrochloride and gatifloxacin in bulk and in pharmaceutical preparations. The method is based upon a kinetic investigation of the oxidation reaction of ...

  15. Kinetics of polymer adsorption, desorption and exchange

    NARCIS (Netherlands)

    Dijt, J.C.

    1993-01-01

    The aim of the study in this thesis was to gain more insight in the kinetics of polymer adsorption. To this end some well-characterised polymers have been systematically investigated.

    In the process of polymer adsorption one may distinguish three kinetic contributions: transport to

  16. Thermodynamic, kinetic and mechanistic investigations of ...

    Indian Academy of Sciences (India)

    J. Chem. Sci. Vol. 128, No. 3, March 2016, pp. 477–485. c Indian Academy of Sciences. DOI 10.1007/s12039-016-1044-x. Thermodynamic, kinetic and mechanistic ... The kinetics of oxidation of piperazine by the copper complex, diperiodatocuprate(III) in alkaline ... of this drug by DPC, there is a need for understanding.

  17. Understanding Kinetic Energy paradox in Quantum Mechanics

    OpenAIRE

    Kornyushin, Yuri

    2008-01-01

    A concept of Kinetic Energy in Quantum Mechanics is analyzed. Kinetic Energy is not zero in many cases where there are no motion and flux. This paradox can be understood, using expansion of the wave function in Fourier integral, that is on the basis of virtual plane waves.

  18. Determination of the kinetics of ethene epoxidation

    NARCIS (Netherlands)

    Schouten, E.P.S.; Schouten, E.P.S.; Borman, P.C.; Borman, P.C.; Westerterp, K.R.

    1996-01-01

    Several problems and pitfalls in the use of laboratory reactors for the determination of the kinetics of ethene epoxidation over industrial silver on α-alumina catalyst are discussed. Also, commonly used methodologies for kinetic studies are dealt with because of the general nature of some problems.

  19. A Comprehensive Enzyme Kinetic Exercise for Biochemistry

    Science.gov (United States)

    Barton, Janice S.

    2011-01-01

    This article describes a comprehensive treatment of experimental enzyme kinetics strongly coupled to electronic data acquisition and use of spreadsheets to organize data and perform linear and nonlinear least-squares analyses, all in a manner that promotes development of important reasoning skills. Kinetic parameters are obtained for the stable…

  20. Enzyme Kinetics? Elementary, my dear 3 -8 ...

    Indian Academy of Sciences (India)

    reactions proceed at useful rates under physiological conditions. We had earlier discussed in Part 11 the basic principles of enzyme catalysis and derived the Michaelis-. Menten equation. In this article, the significance of kinetic parameters and analysis of kinetic data will be discussed. Why should one determine K and V ?

  1. Chemical kinetics and oil shale process design

    Energy Technology Data Exchange (ETDEWEB)

    Burnham, A.K.

    1993-07-01

    Oil shale processes are reviewed with the goal of showing how chemical kinetics influences the design and operation of different processes for different types of oil shale. Reaction kinetics are presented for organic pyrolysis, carbon combustion, carbonate decomposition, and sulfur and nitrogen reactions.

  2. Kinetic study of dehydration of heteropolyacids

    International Nuclear Information System (INIS)

    Mokhosoev, M.V.; Khakhinov, V.V.; Tumurova, L.V.

    1988-01-01

    The thermogravimetric method has been applied to investigate the kinetics of dehydration and decomposition of heteropolyacid hydrates of molybdenum and tungsten of the 12-th series. The obtained values of kinetic parameters of dehydration processes well agree with structural representations on composition of crystal hydrates of heteropolyacids, data on IR spectroscopy and X-ray phase analysis

  3. Enhancing Thai Students' Learning of Chemical Kinetics

    Science.gov (United States)

    Chairam, Sanoe; Somsook, Ekasith; Coll, Richard K.

    2009-01-01

    Chemical kinetics is an extremely important concept for introductory chemistry courses. The literature suggests that instruction in chemical kinetics is often teacher-dominated at both the secondary school and tertiary levels, and this is the case in Thailand--the educational context for this inquiry. The work reported here seeks to shift students…

  4. Saffman-Taylor fingers with kinetic undercooling

    KAUST Repository

    Gardiner, Bennett P. J.

    2015-02-23

    © 2015 American Physical Society. The mathematical model of a steadily propagating Saffman-Taylor finger in a Hele-Shaw channel has applications to two-dimensional interacting streamer discharges which are aligned in a periodic array. In the streamer context, the relevant regularization on the interface is not provided by surface tension but instead has been postulated to involve a mechanism equivalent to kinetic undercooling, which acts to penalize high velocities and prevent blow-up of the unregularized solution. Previous asymptotic results for the Hele-Shaw finger problem with kinetic undercooling suggest that for a given value of the kinetic undercooling parameter, there is a discrete set of possible finger shapes, each analytic at the nose and occupying a different fraction of the channel width. In the limit in which the kinetic undercooling parameter vanishes, the fraction for each family approaches 1/2, suggesting that this "selection" of 1/2 by kinetic undercooling is qualitatively similar to the well-known analog with surface tension. We treat the numerical problem of computing these Saffman-Taylor fingers with kinetic undercooling, which turns out to be more subtle than the analog with surface tension, since kinetic undercooling permits finger shapes which are corner-free but not analytic. We provide numerical evidence for the selection mechanism by setting up a problem with both kinetic undercooling and surface tension and numerically taking the limit that the surface tension vanishes.

  5. Kinetic energy driven pairing in cuprate superconductors

    NARCIS (Netherlands)

    Maier, TA; Jarrell, M; Macridin, A; Slezak, C

    2004-01-01

    Pairing occurs in conventional superconductors through a reduction of the electronic potential energy accompanied by an increase in kinetic energy. In the underdoped cuprates, optical experiments show that pairing is driven by a reduction of the electronic kinetic energy. Using the dynamical cluster

  6. Concepts of radial and angular kinetic energies

    DEFF Research Database (Denmark)

    Dahl, Jens Peder; Schleich, W.P.

    2002-01-01

    We consider a general central-field system in D dimensions and show that the division of the kinetic energy into radial and angular parts proceeds differently in the wave-function picture and the Weyl-Wigner phase-space picture, Thus, the radial and angular kinetic energies are different quantities...

  7. untangling chemical kinetics through tangible and visual

    African Journals Online (AJOL)

    Temechegn

    Chemistry students assimilate material related to kinetics and equilibrium [8-20]. Yet, a gap exits in the application of tools that relate stoichiometry, the consumption of reactant, generation of product, and their representation using graphs, to aid in the comprehension of chemical kinetics. Figure 2: Typical generated.

  8. Hydrogen electrode reaction: A complete kinetic description

    International Nuclear Information System (INIS)

    Quaino, P.M.; Gennero de Chialvo, M.R.; Chialvo, A.C.

    2007-01-01

    The kinetic description of the hydrogen electrode reaction (HER) in the whole range of overpotentials (-0.2 < η (V) < 0.40) is presented. The Volmer-Heyrovsky-Tafel mechanism was solved considering simultaneously the following items: (i) the diffusional contribution of the molecular hydrogen from and towards the electrode surface, (ii) the forward and backward reaction rates of each elementary step and (iii) a Frumkin type adsorption for the reaction intermediate. In order to verify the descriptive capability of the kinetic expressions derived, an experimental study of the HER was carried out on a rotating platinum disc electrode in acid solution. From the correlation of these results the elementary kinetic parameters were evaluated and several aspects related to the kinetic mechanism were discussed. Finally, the use of these kinetic expressions to interpret results obtained on microelectrodes is also analysed

  9. Crystallization Kinetics within a Generic Modeling Framework

    DEFF Research Database (Denmark)

    Meisler, Kresten Troelstrup; von Solms, Nicolas; Gernaey, Krist V.

    2014-01-01

    of employing a well-structured model library for storage, use/reuse, and analysis of the kinetic models are highlighted. Examples illustrating the application of the modeling framework for kinetic model discrimination related to simulation of specific crystallization scenarios and for kinetic model parameter......A new and extended version of a generic modeling framework for analysis and design of crystallization operations is presented. The new features of this framework are described, with focus on development, implementation, identification, and analysis of crystallization kinetic models. Issues related...... to the modeling of various kinetic phenomena like nucleation, growth, agglomeration, and breakage are discussed in terms of model forms, model parameters, their availability and/or estimation, and their selection and application for specific crystallization operational scenarios under study. The advantages...

  10. Myofilament kinetics in isometric twitch dynamics.

    Science.gov (United States)

    Campbell, K B; Razumova, M V; Kirkpatrick, R D; Slinker, B K

    2001-05-01

    To better understand the relationship between kinetic processes of contraction and the dynamic features of an isometric twitch, studies were conducted using a mathematical model that included: (1) kinetics of cross bridge (XB) cycling; (2) kinetics of thin filament regulatory processes; (3) serial and feedback interactions between these two kinetic processes; and (4) time course of calcium activation. Isometric twitch wave forms were predicted, morphometric features of the predicted twitch wave form were evaluated, and sensitivities of wave form morphometric features to model kinetic parameters were assessed. Initially, the impulse response of the XB cycle alone was analyzed with the findings that dynamic constants of the twitch transient were much faster than turnover number of steady-state XB cycling, and, although speed and duration of the twitch wave form were sensitive to XB cycle kinetic constants. parameters of wave shape were not. When thin filament regulatory unit (RU) kinetics were added to XB cycle kinetics, the system impulse response was slowed with only little effect on wave shape. When cooperative neighbor interactions between RU and XB were added, twitch wave shape (as well as amplitude, speed and duration) proved to be sensitive to variation in cooperativity. Importantly, persistence and shape of the falling phase could be strongly modified. When kinetic coefficients of XB attachment were made to depend on sarcomere length, changes in wave shape occurred that did not occur when only sliding filament mechanisms were operative. Indeed, the force-length relationship proved to be highly sensitive to length-dependent XB attachment in combination with cooperative interactions. These model findings are the basis of hypotheses for the role of specific kinetic events of contraction in generating twitch wave form features.

  11. Kinetics of DNA tile dimerization.

    Science.gov (United States)

    Jiang, Shuoxing; Yan, Hao; Liu, Yan

    2014-06-24

    Investigating how individual molecular components interact with one another within DNA nanoarchitectures, both in terms of their spatial and temporal interactions, is fundamentally important for a better understanding of their physical behaviors. This will provide researchers with valuable insight for designing more complex higher-order structures that can be assembled more efficiently. In this report, we examined several spatial factors that affect the kinetics of bivalent, double-helical (DH) tile dimerization, including the orientation and number of sticky ends (SEs), the flexibility of the double helical domains, and the size of the tiles. The rate constants we obtained confirm our hypothesis that increased nucleation opportunities and well-aligned SEs accelerate tile-tile dimerization. Increased flexibility in the tiles causes slower dimerization rates, an effect that can be reversed by introducing restrictions to the tile flexibility. The higher dimerization rates of more rigid tiles results from the opposing effects of higher activation energies and higher pre-exponential factors from the Arrhenius equation, where the pre-exponential factor dominates. We believe that the results presented here will assist in improved implementation of DNA tile based algorithmic self-assembly, DNA based molecular robotics, and other specific nucleic acid systems, and will provide guidance to design and assembly processes to improve overall yield and efficiency.

  12. Jacques Polieri: Kinetic Theatre Space

    Directory of Open Access Journals (Sweden)

    Juan Ignacio Prieto López

    2015-10-01

    Full Text Available Between the First and Second World War the definition of the new type of theater building was one of the main tasks of the European Avantgarde. In its design and theoretical formulation were poets, playwrights, theater directors, architects, painters, actors, engineers… from different countries and art movements. Despite the collaboration of the leading members of the Avant-garde like Marinetti, Moholy-Nagy, Kiesler, El Lissitzky, Gropius… none of these proposals were built because of their radical and utopian characteristics. It was a young French theater director, Jacques Polieri, who became the main compiler and prompter of those proposals in postwar Europe in two issues of the French journal Aujourd´hui, art et architecture. The first of them published in May 1958, under the title “Cinquante ans de recherches dans le spectacle” collected the most important experiences in theory, scenography, technic, and theater architecture in the interwar period. Polieri worked with different architects in several projects for theater buildings, whose main feature was the mobility of all their elements and components, trying to get a dynamic experience during the performance. Those proposals related to Kinetic Art, were published in a second issue of Aujourd´hui, art et architecture entitled “Scénographie Nouvelle” in October 1963.

  13. Antioxidant degradation kinetics in apples.

    Science.gov (United States)

    Arora, Bindvi; Sethi, Shruti; Joshi, Alka; Sagar, V R; Sharma, R R

    2018-04-01

    The effect of shelf storage under ambient conditions of cut apple dices on degradation of bioactive compounds such ascorbic acid, total phenols, antioxidant activity (% DPPH inhibition) and PPO activity were investigated. The results indicated that antioxidant activity declined significantly over 80 min storage of diced apples at ambient temperature. Similar trend was observed for ascorbic acid, total phenols and PPO activity. Ascorbic acid, total phenols and antioxidant activity degradation followed first-order kinetics where the rate constant (k) was found to be in range for all the thirteen cultivars, though initial ascorbic acid and phenol content varied in different apple cultivars. The reaction rate constant (k) for first order degradation ranged from 1.16 to 1.97, 0.89 to 1.29 and 0.37 to 1.54 for antioxidant activity, total phenols and ascorbic acid, respectively. This explains that antioxidant activity degrades at higher rate than total phenols and ascorbic acid, which also corroborates that antioxidant activity is affected by both total phenols and ascorbic acid content. In general, total antioxidant activity for apple dices kept for 80 min under ambient conditions exhibited lower values as compared to control.

  14. Complex kinetics of fluctuating enzymes: phase diagram characterization of a minimal kinetic scheme.

    Science.gov (United States)

    Min, Wei; Jiang, Liang; Xie, X Sunney

    2010-05-03

    Enzyme molecules are dynamic entities with stochastic fluctuation in both protein conformation and enzymatic activity. However, such a notion of fluctuating enzymes, best characterized by recent single-molecule experiments, was not considered in the classic Michaelis-Menten (MM) kinetic scheme. Here we incorporate the fluctuation concept into the reversible MM scheme, and solve analytically all the possible kinetics (i.e., substrate concentration dependent enzymatic velocity) for a minimal model of fluctuating enzymes. Such a minimal model is found to display a variety of distinct kinetic behaviors (phases) in addition to the classic MM kinetics; excess substrate inhibition, sigmoidal kinetics, and concave biphasic kinetics. We find that all these kinetic phases are interrelated and unified under the framework of fluctuating enzymes and can be adequately described by a phase diagram that consists of two master parameters. Functionally, substrate inhibition, sigmoidal kinetics, and convex biphasic phases exhibit positive cooperativity, whereas concave biphasic phases display negative cooperativity. Remarkably, all these complex kinetics are produced by fluctuating enzymes with single substrate binding site, but the two conformations are, therefore, fundamentally different from the classic MWC and KNF models that require multiple subunit or binding sites. This model also suggests that, for a given enzyme/substrate pair, the non-MM behaviors could undergo transitions among different kinetic phases induced by varying product concentrations, owing to the fundamental Haldane symmetry in the reversible MM scheme.

  15. Anomalously fast kinetics of lipid monolayer buckling

    Science.gov (United States)

    Oppenheimer, Naomi; Diamant, Haim; Witten, Thomas A.

    2013-08-01

    We reexamine previous observations of folding kinetics of compressed lipid monolayers in light of the accepted mechanical buckling mechanism recently proposed by L. Pocivavsek [ScienceSCIEAS0036-807510.1126/science.1154069 320, 912 (2008)]. Using simple models, we set conservative limits on (a) the energy released in the mechanical buckling process and (b) the kinetic energy entailed by the observed folding motion. These limits imply a kinetic energy at least 30 times greater than the energy supplied by the buckling instability. We discuss possible extensions of the accepted picture that might resolve this discrepancy.

  16. The kinetics of normal and prosthetic wrists.

    Science.gov (United States)

    Tolbert, J R; Blair, W F; Andrews, J G; Crowninshield, R D

    1985-01-01

    The purposes of this study were (1) to describe normal wrist kinetics, and (2) to investigate the in-vitro kinetics of four currently available wrist prostheses (Swanson, Meuli, Volz, Hamas). The effective tendon moment arms of the six major wrist muscles were determined through the use of load cells and applied weights. Testing was conducted in a neutral wrist configuration with hand pronation-supination both constrained and unconstrained. The results indicate that each of the muscles studied has a unique set of effective tendon moment arms about the normal wrist as well as about wrists with the implanted prostheses, and that none of the prosthetic wrists studied duplicated normal wrist kinetics.

  17. Modeling of Reactor Kinetics and Dynamics

    Energy Technology Data Exchange (ETDEWEB)

    Matthew Johnson; Scott Lucas; Pavel Tsvetkov

    2010-09-01

    In order to model a full fuel cycle in a nuclear reactor, it is necessary to simulate the short time-scale kinetic behavior of the reactor as well as the long time-scale dynamics that occur with fuel burnup. The former is modeled using the point kinetics equations, while the latter is modeled by coupling fuel burnup equations with the kinetics equations. When the equations are solved simultaneously with a nonlinear equation solver, the end result is a code with the unique capability of modeling transients at any time during a fuel cycle.

  18. Liquefaction chemistry and kinetics: Hydrogen utilization studies

    Energy Technology Data Exchange (ETDEWEB)

    Rothenberger, K.S.; Warzinski, R.P.; Cugini, A.V. [Pittsburgh Energy Technology Center, PA (United States)] [and others

    1995-12-31

    The objectives of this project are to investigate the chemistry and kinetics that occur in the initial stages of coal liquefaction and to determine the effects of hydrogen pressure, catalyst activity, and solvent type on the quantity and quality of the products produced. The project comprises three tasks: (1) preconversion chemistry and kinetics, (2) hydrogen utilization studies, and (3) assessment of kinetic models for liquefaction. The hydrogen utilization studies work will be the main topic of this report. However, the other tasks are briefly described.

  19. Classical Antiferromagnetism in Kinetically Frustrated Electronic Models

    Science.gov (United States)

    Sposetti, C. N.; Bravo, B.; Trumper, A. E.; Gazza, C. J.; Manuel, L. O.

    2014-05-01

    We study, by means of the density matrix renormalization group, the infinite U Hubbard model—with one hole doped away from half filling—in triangular and square lattices with frustrated hoppings, which invalidate Nagaoka's theorem. We find that these kinetically frustrated models have antiferromagnetic ground states with classical local magnetization in the thermodynamic limit. We identify the mechanism of this kinetic antiferromagnetism with the release of the kinetic energy frustration, as the hole moves in the established antiferromagnetic background. This release can occur in two different ways: by a nontrivial spin Berry phase acquired by the hole, or by the effective vanishing of the hopping amplitude along the frustrating loops.

  20. Chemical Kinetic Modeling of 2-Methylhexane Combustion

    KAUST Repository

    Mohamed, Samah Y.

    2015-03-30

    Accurate chemical kinetic combustion models of lightly branched alkanes (e.g., 2-methylalkanes) are important for investigating the combustion behavior of diesel, gasoline, and aviation fuels. Improving the fidelity of existing kinetic models is a necessity, as new experiments and advanced theories show inaccuracy in certain portions of the models. This study focuses on updating thermodynamic data and kinetic model for a gasoline surrogate fuel, 2-methylhexane, with recently published group values and rate rules. These update provides a better agreement with rapid compression machine measurements of ignition delay time, while also strengthening the fundamental basis of the model.

  1. Nuclear reactor kinetics and plant control

    CERN Document Server

    Oka, Yoshiaki

    2013-01-01

    Understanding time-dependent behaviors of nuclear reactors and the methods of their control is essential to the operation and safety of nuclear power plants. This book provides graduate students, researchers, and engineers in nuclear engineering comprehensive information on both the fundamental theory of nuclear reactor kinetics and control and the state-of-the-art practice in actual plants, as well as the idea of how to bridge the two. The first part focuses on understanding fundamental nuclear kinetics. It introduces delayed neutrons, fission chain reactions, point kinetics theory, reactivit

  2. Research in Chemical Kinetics, v.3

    CERN Document Server

    2012-01-01

    This series of volumes aims to publish authoritative review articles on a wide range of exciting and contemporary topics in gas and condensed phase kinetics. Research in Chemical Kinetics complements the acclaimed series Comprehensive Chemical Kinetics, and is edited by the same team of professionals. The reviews contained in this volume are concise, topical accounts of specific research written by acknowledged experts. The authors summarize their latest work and place it in a general context. Particular strengths of the volume are the quality of the contributions and their top

  3. Research in chemical kinetics, v.2

    CERN Document Server

    1994-01-01

    This is the second volume in a new series, which aims to publish authoritative review articles on a wide range of exciting and contemporary topics in gas and condensed phase kinetics. Research in Chemical Kinetics complements the acclaimed series Comprehensive Chemical Kinetics, and is edited by the same team of professionals. The reviews contained in this volume are concise, topical accounts of specific research written by acknowledged experts. The authors summarize their latest work and place it in a general context. Particular strengths of the volume are the quality of the c

  4. Isoconversional kinetics of thermally stimulated processes

    CERN Document Server

    Vyazovkin, Sergey

    2015-01-01

    The use of isoconversional kinetic methods for analysis of thermogravimetric and calorimetric data on thermally stimulated processes is quickly growing in popularity. The purpose of this book is to create the first comprehensive resource on the theory and applications of isoconversional methodology. The book introduces the reader to the kinetics of physical and chemical condensed phase processes that occur as a result of changing temperature and discusses how isoconversional analysis can provide important kinetic insights into them. The book will help the readers to develop a better understanding of the methodology, and promote its efficient usage and successful development.

  5. On the relationships between the Michaelis-Menten kinetics, reverse Michaelis-Menten kinetics, equilibrium chemistry approximation kinetics, and quadratic kinetics

    Science.gov (United States)

    Tang, J. Y.

    2015-12-01

    The Michaelis-Menten kinetics and the reverse Michaelis-Menten kinetics are two popular mathematical formulations used in many land biogeochemical models to describe how microbes and plants would respond to changes in substrate abundance. However, the criteria of when to use either of the two are often ambiguous. Here I show that these two kinetics are special approximations to the equilibrium chemistry approximation (ECA) kinetics, which is the first-order approximation to the quadratic kinetics that solves the equation of an enzyme-substrate complex exactly for a single-enzyme and single-substrate biogeochemical reaction with the law of mass action and the assumption of a quasi-steady state for the enzyme-substrate complex and that the product genesis from enzyme-substrate complex is much slower than the equilibration between enzyme-substrate complexes, substrates, and enzymes. In particular, I show that the derivation of the Michaelis-Menten kinetics does not consider the mass balance constraint of the substrate, and the reverse Michaelis-Menten kinetics does not consider the mass balance constraint of the enzyme, whereas both of these constraints are taken into account in deriving the equilibrium chemistry approximation kinetics. By benchmarking against predictions from the quadratic kinetics for a wide range of substrate and enzyme concentrations, the Michaelis-Menten kinetics was found to persistently underpredict the normalized sensitivity ∂ ln v / ∂ ln k2+ of the reaction velocity v with respect to the maximum product genesis rate k2+, persistently overpredict the normalized sensitivity ∂ ln v / ∂ ln k1+ of v with respect to the intrinsic substrate affinity k1+, persistently overpredict the normalized sensitivity ∂ ln v / ∂ ln [E]T of v with respect the total enzyme concentration [E]T, and persistently underpredict the normalized sensitivity ∂ ln v / ∂ ln [S]T of v with respect to the total substrate concentration [S]T. Meanwhile, the

  6. Kinetics interpretation model of isothermal martensite reactions

    International Nuclear Information System (INIS)

    Guimaraes, J.R.C.

    1976-01-01

    It was discussed details associated to the interpretation of kinetics of martencite heterogeneous nucleation in isothermal reactions. It was proposed a model which allows compute the variation of concentration of preferencial sites nucleation with a volumetric martencite fraction [pt

  7. Kinetic Study of Curcumin on Modal Fabric

    Directory of Open Access Journals (Sweden)

    Abu Naser Md. Ahsanul Haque

    2018-03-01

    Full Text Available A kinetic study of curcumin on modal fabric was carried out using an initial dye concentration of 1 g/L at three different temperatures, 70 °C, 85 °C and 100 °C, at pH 7 and an material to liquor ratio of 1:20. Pseudo first-order and pseudo second-order kinetics were applied, and it was found that the adsorption kinetics of curcumin on modal fabric matched the pseudo second-order kinetic model. The activation energy was found to be equal to 71.14 kJ/mol, while the enthalpy and entropy of activation were 68.16 kJ/mol and –66.02 J/molK respectively.

  8. Electron Kinetics in Hypersonic Plasmas, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — The goal of this SBIR project is to advance the state-of-the-art in computations of hypersonic plasmas by adding high-fidelity kinetic models for electrons. Electron...

  9. Kinetics of oxidic phase dissolution in acids

    International Nuclear Information System (INIS)

    Gorichev, I.G.; Kipriyanov, N.A.

    1981-01-01

    The critical analysis of the experimental data on dissolution kinetics of metal oxides (BeO, V 2 O 5 , UO 2 , Nb 2 O 5 , Ta 2 O 5 etc.) in acid media is carried out. Kinetic peculiarities of oxide dissolution are explained on the basis of the notions of electron- proton theory. It is established that the surface nonstoichiometric ccomposition of oxide phase and potential jump, appearing on the interface of the oxide-electrolyte phase are the important factors, determining the dissolution rate of a solid phase. The dissolution rate of metal oxides is limited by the transition of protons into the solid oxide phase. Morphological models of heterogeneous kinetics are used when explaining kinetic regularities of oxide dissolution process [ru

  10. Kinetic Theory of the Inner Magnetospheric Plasma

    CERN Document Server

    Khazanov, George V

    2011-01-01

    This book provides a broad introduction to the kinetic theory of space plasma physics with the major focus on the inner magnetospheric plasma. It is designed to provide a comprehensive description of the different kinds of transport equations for both plasma particles and waves with an emphasis on the applicability and limitations of each set of equations. The major topics are: Kinetic Theory of Superthermal Electrons, Kinetic Foundation of the Hydrodynamic Description of Space Plasmas (including wave-particle interaction processes), and Kinetic Theory of the Terrestrial Ring Current. Distinguishable features of this book are the analytical solutions of simplified transport equations. Approximate analytic solutions of transport phenomena are very useful because they help us gain physical insight into how the system responds to varying sources of mass, momentum and energy and also to various external boundary conditions. They also provide us a convenient method to test the validity of complicated numerical mod...

  11. Kinetics and Mechanism--A Games Approach.

    Science.gov (United States)

    Harsch, Gunther

    1984-01-01

    Proposes an approach to chemical kinetics and mechanism using statistical games, illustrating its use in monomolecular, catalytic, autocatalytic, consecutive, and equilibrium reactions. Major features of the games are also outlined and discussed. (JN)

  12. Reduced Chemical Kinetic Mechanisms for Hydrocarbon Fuels

    National Research Council Canada - National Science Library

    Montgomery, Christopher J; Cremer, Marc A; Heap, Michael P; Chen, Jhy-Yuan; Westbrook, Charles K; Maurice, Lourdes Q

    1999-01-01

    Using CARM (Computer Aided Reduction Method), a computer program that automates the mechanism reduction process, a variety of different reduced chemical kinetic mechanisms for ethylene and n-heptane have been generated...

  13. A mathematical model for iodine kinetics

    International Nuclear Information System (INIS)

    Silva, E.A.T. da.

    1976-01-01

    A mathematical model for the iodine kinetics in thyroid is presented followed by its analytical solution. An eletroanalogical model is also developed for a simplified stage and another is proposed for the main case [pt

  14. Kinetic investigation on enantioselective hydrolytic resolution of ...

    African Journals Online (AJOL)

    Kinetic investigation on enantioselective hydrolytic resolution of epichlorohydrin by crude epoxide hydrolase from domestic duck liver. X Ling, D Lu, J Wang, J Chen, L Ding, J Chen, H Chai, P Ouyang ...

  15. Kinetics of microwave drying of apples

    Directory of Open Access Journals (Sweden)

    G. V. Kalashnikov

    2012-01-01

    Full Text Available The influence of main technological parameters was studied as a result of research of microwave drying of apples and the analysis of kinetic regularity of the process was performed.

  16. Kinetic model for polyhydroxybutyrate (PHB) production by ...

    African Journals Online (AJOL)

    USER

    2010-05-24

    May 24, 2010 ... Key words: Kinetic model, polyhydroxyalkanoates, Hydrogenophaga pseudoflava, logistic model, Monod, biopolymer. INTRODUCTION. Polyhydroxybutyrate (PHB) is a biopolymer that can be used as a biodegradable thermoplastic material for waste management strategies and biocompatibility in medical.

  17. Plasma heating by kinetic Alfven wave

    International Nuclear Information System (INIS)

    Assis, A.S. de.

    1982-01-01

    The heating of a nonuniform plasma (electron-ion) due to the resonant excitation of the shear Alfven wave in the low β regime is studied using initially the ideal MHD model and posteriorly using the kinetic model. The Vlasov equation for ions and the drift kinetic equation for electrons have been used. Through the ideal MHD model, it is concluded that the energy absorption is due to the continuous spectrum (phase mixing) which the shear Alfven wave has in a nonuniform plasma. An explicit expression for the energy absorption is derived. Through the kinetic model it is concluded that the energy absorption is due to a resonant mode convertion of the incident wave into the kinetic Alfven wave which propagates away from the resonant region. Its electron Landau damping has been observed. There has been a concordance with the MHD calculations. (Author) [pt

  18. Some concepts in condensed phase chemical kinetics

    International Nuclear Information System (INIS)

    Adelman, S.A.

    1986-01-01

    Some concepts in condensed phase chemical kinetics which have emerged from a recent rigorous statistical mechanical treatment of condensed phase chemical reaction dynamics (S.A. Adelman, Adv. Chem. Phys.53:61 (1983)) are discussed in simple physical terms

  19. Fundamental aspects of plasma chemical physics kinetics

    CERN Document Server

    Capitelli, Mario; Colonna, Gianpiero; Esposito, Fabrizio; Gorse, Claudine; Hassouni, Khaled; Laricchiuta, Annarita; Longo, Savino

    2016-01-01

    Describing non-equilibrium "cold" plasmas through a chemical physics approach, this book uses the state-to-state plasma kinetics, which considers each internal state as a new species with its own cross sections. Extended atomic and molecular master equations are coupled with Boltzmann and Monte Carlo methods to solve the electron energy distribution function. Selected examples in different applied fields, such as microelectronics, fusion, and aerospace, are presented and discussed including the self-consistent kinetics in RF parallel plate reactors, the optimization of negative ion sources and the expansion of high enthalpy flows through nozzles of different geometries. The book will cover the main aspects of the state-to-state kinetic approach for the description of nonequilibrium cold plasmas, illustrating the more recent achievements in the development of kinetic models including the self-consistent coupling of master equations and Boltzmann equation for electron dynamics. To give a complete portrayal, the...

  20. Progress in antenna coupled kinetic inductance detectors

    NARCIS (Netherlands)

    Baryshev, A.; Baselmans, J.J.A.; Freni, A.; Gerini, G.; Hoevers, H.; Iacono, A.; Neto, A.

    2011-01-01

    This paper describes the combined Dutch efforts toward the development of large wideband focal plane array receivers based on kinetic inductance detectors (KIDs). Taking into account strict electromagnetic and detector sensitivity requirements for future ground and space based observatories, this

  1. Nitrogen uptake kinetics of freshly isolated zooxanthellae

    Digital Repository Service at National Institute of Oceanography (India)

    Wafar; Wafar; Rajkumar, R.

    Zooxanthellae freshly isolated from the coral host Pocillopora damicornis exhibited substrate-saturable uptake kinetics for ammonium, nitrate and urea. Maximum uptake velocity for ammonium [10.1 nmol. ( mu chl-a)./1h/1] was greater than...

  2. Practical steady-state enzyme kinetics.

    Science.gov (United States)

    Lorsch, Jon R

    2014-01-01

    Enzymes are key components of most biological processes. Characterization of enzymes is therefore frequently required during the study of biological systems. Steady-state kinetics provides a simple and rapid means of assessing the substrate specificity of an enzyme. When combined with site-directed mutagenesis (see Site-Directed Mutagenesis), it can be used to probe the roles of particular amino acids in the enzyme in substrate recognition and catalysis. Effects of interaction partners and posttranslational modifications can also be assessed using steady-state kinetics. This overview explains the general principles of steady-state enzyme kinetics experiments in a practical, rather than theoretical, way. Any biochemistry textbook will have a section on the theory of Michaelis-Menten kinetics, including derivations of the relevant equations. No specific enzymatic assay is described here, although a method for monitoring product formation or substrate consumption over time (an assay) is required to perform the experiments described. © 2014 Elsevier Inc. All rights reserved.

  3. Kinetic Theory of Granular Gases

    International Nuclear Information System (INIS)

    Trizac, Emmanuel

    2005-01-01

    Granular gases are composed of macroscopic bodies kept in motion by an external energy source such as a violent shaking. The behaviour of such systems is quantitatively different from that of ordinary molecular gases: due to the size of the constituents, external fields have a stronger effect on the dynamics and, more importantly, the kinetic energy of the gas is no longer a conserved quantity. The key role of the inelasticity of collisions has been correctly appreciated for about fifteen years, and the ensuing consequences in terms of phase behaviour or transport properties studied in an increasing and now vast body of literature. The purpose of this book is to help the newcomer to the field in acquiring the essential theoretical tools together with some numerical techniques. As emphasized by the authors-who were among the pioneers in the domain- the content could be covered in a one semester course for advanced undergraduates, or it could be incorporated in a more general course dealing with the statistical mechanics of dissipative systems. The book is self-contained, clear, and avoids mathematical complications. In order to elucidate the main physical ideas, heuristic points of views are sometimes preferred to a more rigorous route that would lead to a longer discussion. The 28 chapters are short; they offer exercises and worked examples, solved at the end of the book. Each part is supplemented with a relevant foreword and a useful summary including take-home messages. The editorial work is of good quality, with very few typographical errors. In spite of the title, kinetic theory stricto sensu is not the crux of the matter covered. The authors discuss the consequences of the molecular chaos assumption both at the individual particle level and in terms of collective behaviour. The first part of the book addresses the mechanics of grain collisions. It is emphasized that considering the coefficient of restitution ε -a central quantity governing the inelasticity of

  4. Thermodynamically Feasible Kinetic Models of Reaction Networks

    OpenAIRE

    Ederer, Michael; Gilles, Ernst Dieter

    2007-01-01

    The dynamics of biological reaction networks are strongly constrained by thermodynamics. An holistic understanding of their behavior and regulation requires mathematical models that observe these constraints. However, kinetic models may easily violate the constraints imposed by the principle of detailed balance, if no special care is taken. Detailed balance demands that in thermodynamic equilibrium all fluxes vanish. We introduce a thermodynamic-kinetic modeling (TKM) formalism that adapts th...

  5. Enzyme kinetics informatics: From instrument to browser

    OpenAIRE

    Swainston, Neil; Golebiewski, Martin; Messiha, Hanan L.; Malys, Naglis; Kania, Renate; Kengne, Sylvestre; Krebs, Olga; Mir, Saqib; Sauer-Danzwith, Heidrun; Smallbone, Kieran; Weidemann, Andreas; Wittig, Ulrike; Kell, Douglas B.; Mendes, Pedro; Müller, Wolfgang

    2010-01-01

    A limited number of publicly available resources provide access to enzyme kinetic parameters. These have been compiled through manual data mining of published papers, not from the original, raw experimental data from which the parameters were calculated. This is largely due to the lack of software or standards to support the capture, analysis, storage and dissemination of such experimental data. Introduced here is an integrative system to manage experimental enzyme kinetics data from instrume...

  6. Kinetics and Product Channels in Combustion Chemistry

    Energy Technology Data Exchange (ETDEWEB)

    Hershberger, John F. [North Dakota State Univ., Fargo, ND (United States)

    2017-02-28

    We report study of the chemical kinetics and/or photochemistry of several chemical reactions of potential interest in understanding the gas phase combustion chemistry of nitrogen-containing molecules. Studies completed during the final grant period include determination of quantum yields of the photolysis of HCNO, fulminic acid, a kinetics and product channel study of the reaction of CN radicals with methyl bromide, and study of the products of the reaction of hydroxymethyl radical with nitric oxide.

  7. Thermal physics kinetic theory and thermodynamics

    CERN Document Server

    Singh, Devraj; Yadav, Raja Ram

    2016-01-01

    THERMAL PHYSICS: Kinetic Theory and Thermodynamics is designed for undergraduate course in Thermal Physics and Thermodynamics. The book provides thorough understanding of the fundamental principles of the concepts in Thermal Physics. The book begins with kinetic theory, then moves on liquefaction, transport phenomena, the zeroth, first, second and third laws, thermodynamics relations and thermal conduction. The book concluded with radiation phenomenon. KEY FEATURES: * Include exercises * Short Answer Type Questions * Long Answer Type Questions * Numerical Problems * Multiple Choice Questions

  8. NLTE4 Plasma Population Kinetics Database

    Science.gov (United States)

    SRD 159 NLTE4 Plasma Population Kinetics Database (Web database for purchase)   This database contains benchmark results for simulation of plasma population kinetics and emission spectra. The data were contributed by the participants of the 4th Non-LTE Code Comparison Workshop who have unrestricted access to the database. The only limitation for other users is in hidden labeling of the output results. Guest users can proceed to the database entry page without entering userid and password.

  9. Ozone mass transfer and kinetics experiments

    International Nuclear Information System (INIS)

    Bollyky, L.J.; Beary, M.M.

    1981-12-01

    Experiments were conducted at the Hanford Site to determine the most efficient pH and temperature levels for the destruction of complexants in Hanford high-level defense waste. These complexants enhance migration of radionuclides in the soil and inhibit the growth of crystals in the evaporator-crystallizer. Ozone mass transfer and kinetics tests have been outlined for the determination of critical mass transfer and kinetics parameters of the ozone-complexant reaction

  10. Disorders of cell kinetics and differentiation.

    Science.gov (United States)

    Tüzün, Yalçin; Dolar, Neslihan; Keskin, Sadiye; Wolf, Ronni

    2007-10-01

    The kinetics of cells, keratin, and lipids in the skin could provide useful information about skin biology in health and disease. The kinetics of skin cell turnover are of interest for a variety of physiologic and pathologic conditions. There are also uncertainties regarding the extent of keratinocyte turnover in various skin diseases. Hyperproliferation may represent a risk factor for skin cancer and occurs in physiologic conditions such as wound healing.

  11. Kinetic Damping of Toroidal Alfven Eigenmodes

    International Nuclear Information System (INIS)

    Fu, G.Y.; Berk, H.L.; Pletzer, A.

    2005-01-01

    The damping of Toroidal Alfven Eigenmodes in JET plasmas is investigated by using a reduced kinetic model. Typically no significant damping is found to occur near the center of the plasma due to mode conversion to kinetic Alfven waves. In contrast, continuum damping from resonance near the plasma edge may be significant, and when it is, it gives rise to damping rates that are compatible with the experimental observations

  12. Spatial neutron kinetic module of ROSA code

    International Nuclear Information System (INIS)

    Cherezov, A.L.; Shchukin, N.V.

    2009-01-01

    A spatial neutron kinetic module was developed for computer code ROSA. The paper describes a numerical scheme used in the module for resolving neutron kinetic equations. Analytical integration for delayed neutrons emitters method and direct numerical integration method (Gear's method) were analyzed. The two methods were compared on their efficiency and accuracy. Both methods were verified with test problems. The results obtained in the verification studies were presented [ru

  13. Neutron inverse kinetics via Gaussian Processes

    International Nuclear Information System (INIS)

    Picca, Paolo; Furfaro, Roberto

    2012-01-01

    Highlights: ► A novel technique for the interpretation of experiments in ADS is presented. ► The technique is based on Bayesian regression, implemented via Gaussian Processes. ► GPs overcome the limits of classical methods, based on PK approximation. ► Results compares GPs and ANN performance, underlining similarities and differences. - Abstract: The paper introduces the application of Gaussian Processes (GPs) to determine the subcriticality level in accelerator-driven systems (ADSs) through the interpretation of pulsed experiment data. ADSs have peculiar kinetic properties due to their special core design. For this reason, classical – inversion techniques based on point kinetic (PK) generally fail to generate an accurate estimate of reactor subcriticality. Similarly to Artificial Neural Networks (ANNs), Gaussian Processes can be successfully trained to learn the underlying inverse neutron kinetic model and, as such, they are not limited to the model choice. Importantly, GPs are strongly rooted into the Bayes’ theorem which makes them a powerful tool for statistical inference. Here, GPs have been designed and trained on a set of kinetics models (e.g. point kinetics and multi-point kinetics) for homogeneous and heterogeneous settings. The results presented in the paper show that GPs are very efficient and accurate in predicting the reactivity for ADS-like systems. The variance computed via GPs may provide an indication on how to generate additional data as function of the desired accuracy.

  14. Field-theoretic calculation of kinetic helicity flux

    Indian Academy of Sciences (India)

    In the inertial range the kinetic helicity flux is found to be constant and forward. The universal constant KH appearing in the spectrum of kinetic helicity was found to be. 2.47. Keywords. Kinetic helicity; helical turbulence. PACS Nos 47.27.Ak; 47.27.Gs. Kinetic helicity plays an important role in the dynamics of turbulence.

  15. Thermal dehydration kinetics of phosphogypsum

    Directory of Open Access Journals (Sweden)

    López, F. A.

    2015-09-01

    Full Text Available Phsophogypsum is a by-product from the processing phosphate rock. Before the use of it in cement industry such as setting regulator is necessary a study of dehydration reaction of phosphogypsum to avoid the false setting during the milling. The aim is to study the thermal behavior of two different phosphogypsum sources (Spain and Tunisia under non-isothermal conditions in argon atmosphere by using Thermo-Gravimetriy, Differential Thermal Analysis (TG-DTA and Differential Scanning Calorimetry (DSC. DSC experiments were carried out at temperatures ranging from ambient to 350 °C at different heating rates. The temperatures of conversion from gypsum to hemihydrate and anhydrite states and heat of dehydration were determined. Various methods were used to analyze the DSC data for reaction kinetics determination. The activation energy and frequency factor were calculated for dehydration of phosphogypsum. Activation energy values of the main dehydration reaction of phosphogypsum were calculated to be approximately 61–118 kJ/mol.El fosfoyeso es un subproducto procedente del procesado de la roca fosfato. Una de las posibles vías de reutilización y revalorización es su uso como regulador del fraguado en la industria cementera. Debido a los posibles problemas de falso fraguado asociado a los procesos de deshidratación que tienen lugar durante la molienda del cemento, esta investigación estudió el comportamiento térmico, bajo condiciones no-isotérmicas en atmósfera de argón, de dos fosfoyesos, mediante TG-DTA y DSC. Los ensayos de DSC se realizaron hasta los 350 °C a diferentes velocidades de calentamiento. La temperatura de conversión del yeso a las formas de hemihidrato y anhidrita y el calor de hidratación fueron determinados. Las cinéticas de reacción fueron obtenidas analizando los datos de DSC mediante varios métodos. Se calculó la energía de activación y el factor de frecuencia para las reacciones de deshidratación del

  16. Stochastic theory of interfacial enzyme kinetics: A kinetic Monte Carlo study

    International Nuclear Information System (INIS)

    Das, Biswajit; Gangopadhyay, Gautam

    2012-01-01

    Graphical abstract: Stochastic theory of interfacial enzyme kinetics is formulated. Numerical results of macroscopic phenomenon of lag-burst kinetics is obtained by using a kinetic Monte Carlo approach to single enzyme activity. Highlights: ► An enzyme is attached with the fluid state phospholipid molecules on the Langmuir monolayer. ► Through the diffusion, the enzyme molecule reaches the gel–fluid interface. ► After hydrolysing a phospholipid molecule it predominantly leaves the surface in the lag phase. ► The enzyme is strictly attached to the surface with scooting mode of motion and the burst phase appears. - Abstract: In the spirit of Gillespie’s stochastic approach we have formulated a theory to explore the advancement of the interfacial enzyme kinetics at the single enzyme level which is ultimately utilized to obtain the ensemble average macroscopic feature, lag-burst kinetics. We have provided a theory of the transition from the lag phase to the burst phase kinetics by considering the gradual development of electrostatic interaction among the positively charged enzyme and negatively charged product molecules deposited on the phospholipid surface. It is shown that the different diffusion time scales of the enzyme over the fluid and product regions are responsible for the memory effect in the correlation of successive turnover events of the hopping mode in the single trajectory analysis which again is reflected on the non-Gaussian distribution of turnover times on the macroscopic kinetics in the lag phase unlike the burst phase kinetics.

  17. Kinetics, mechanism, and inhibition of monoamine oxidase.

    Science.gov (United States)

    Ramsay, Rona R; Albreht, Alen

    2018-03-07

    Monoamine oxidases (MAOs) catalyse the oxidation of neurotransmitter amines and a wide variety of primary, secondary and tertiary amine xenobiotics, including therapeutic drugs. While inhibition of MAO activity in the periphery removes protection from biogenic amines and so is undesirable, inhibition in the brain gives vital antidepressant and behavioural advantages that make MAO a major pharmaceutical target for inhibitor design. In neurodegenerative diseases, MAO inhibitors can help to maintain neurotransmitter levels, making it a common feature in novel multi-target combinations designed to combat Alzheimer's disease, albeit not yet proven clinically. Vital information for inhibitor design comes from an understanding of the structure, mechanism, and kinetics of the catalyst. This review will summarize the kinetic behaviour of MAO A and B and the kinetic evaluation of reversible inhibitors that transiently decrease catalysis. Kinetic parameters and crystal structures have enabled computational approaches to ligand discovery and validation of hits by docking. Kinetics and a wide variety of substrates and inhibitors along with theoretical modelling have also contributed to proposed schemes for the still debated chemical mechanism of amine oxidation. However, most of the marketed MAO drugs are long-lasting irreversible inactivators. The mechanism of irreversible inhibition by hydrazine, cyclopropylamine, and propargylamine drugs will be discussed. The article finishes with some examples of the propargylamine moiety in multi-target ligand design to combat neurodegeneration.

  18. The Application of Biomimicry in Kinetic Facades

    Directory of Open Access Journals (Sweden)

    Wijdan Deyaa Abdul Jalil

    2016-10-01

    Full Text Available Biomimicry, as a way of thinking to go back to nature for inspiration, has its impact on many contemporary technological achievements. Some of them are used to design and construct kinetic facades in architecture, because of the importance role of facades in reducing sun radiation, that enter the building through using shading systems and components. In light of this, research problem is determined: "Do technologies which are inspired by biomimicry effect shading in kinetic facades through its characteristics in materials and the mechanics. So the research identifies its goal as: "To identify the types of kinetic facades in buildings and their characteristics as materials and shading mechanism associated with the biomimicry. The research explains the basic types of kinetic facades depending on the technology and materials used to provide the possibility of reducing solar radiation that enters the building. It also compares the case studies which have been chosen in their inspiration concept from biological world, which reflect on the system used of protecting against sun and reducing energy consumption as the designer teams suggest. The research concluded that kinetic façade which is depending on smart materials is self-responding and don't need energy to operate, so it is better in reducing consumption of energy.

  19. NADH peroxidase: kinetic mechanism and nucleotide specificity

    Energy Technology Data Exchange (ETDEWEB)

    Stoll, V.S.; Blanchard, J.S.

    1987-05-01

    NADH peroxidase is a flavoprotein reductase isolated from Streptococcus faecalis which catalyzes the pyridine nucleotide dependent reduction of hydrogen peroxide to water. Initial velocity, product and dead-end inhibition studies have been performed and all support a ping-pong kinetic mechanism. Further support for the ping-pong nature of the kinetic mechanism are the hydrogen peroxide independent transhydrogenase activity of the enzyme, measured either with thio-NAD or with radiolabeled NAD (isotope exchange studies). Kinetic parameters will be presented for a number of reduced pyridine nucleotide analogs. Analogs which have been modified in the adenine ring exhibit much higher K/sub m/'s relative to their adenine analogs. NADH peroxidase catalyzes the stereo-specific removal of the 4S hydrogen of NADH and primary deuterium kinetic isotope effects have been determined for a number of these substrates with 4S-deuterated molecules. There is a strong correlation between their steady-state K/sub m/ and /sup D/V/K. Small values for /sup D/V are interpreted as supporting rate-limitation in the oxidative half-reaction. These data will be discussed in terms of a kinetic and chemical mechanism proposed for NADH peroxidase.

  20. NADH peroxidase: kinetic mechanism and nucleotide specificity

    International Nuclear Information System (INIS)

    Stoll, V.S.; Blanchard, J.S.

    1987-01-01

    NADH peroxidase is a flavoprotein reductase isolated from Streptococcus faecalis which catalyzes the pyridine nucleotide dependent reduction of hydrogen peroxide to water. Initial velocity, product and dead-end inhibition studies have been performed and all support a ping-pong kinetic mechanism. Further support for the ping-pong nature of the kinetic mechanism are the hydrogen peroxide independent transhydrogenase activity of the enzyme, measured either with thio-NAD or with radiolabeled NAD (isotope exchange studies). Kinetic parameters will be presented for a number of reduced pyridine nucleotide analogs. Analogs which have been modified in the adenine ring exhibit much higher K/sub m/'s relative to their adenine analogs. NADH peroxidase catalyzes the stereo-specific removal of the 4S hydrogen of NADH and primary deuterium kinetic isotope effects have been determined for a number of these substrates with 4S-deuterated molecules. There is a strong correlation between their steady-state K/sub m/ and /sup D/V/K. Small values for /sup D/V are interpreted as supporting rate-limitation in the oxidative half-reaction. These data will be discussed in terms of a kinetic and chemical mechanism proposed for NADH peroxidase

  1. Transient processes in cell proliferation kinetics

    CERN Document Server

    Yakovlev, Andrej Yu

    1989-01-01

    A mathematician who has taken the romantic decision to devote himself to biology will doubtlessly look upon cell kinetics as the most simple and natural field of application for his knowledge and skills. Indeed, the thesaurus he is to master is not so complicated as, say, in molecular biology, the structural elements of the system, i. e. ceils, have been segregated by Nature itself, simple considerations of balance may be used for deducing basic equations, and numerous analogies in other areas of science also superficial add to one"s confidence. Generally speaking, this number of impression is correct, as evidenced by the very great theoretical studies on population kinetics, unmatched in other branches of mathematical biology. This, however, does not mean that mathematical theory of cell systems has traversed in its development a pathway free of difficulties or errors. The seeming ease of formalizing the phenomena of cell kinetics not infrequently led to the appearance of mathematical models lacking in adequ...

  2. Nonlocal kinetic-energy-density functionals

    International Nuclear Information System (INIS)

    Garcia-Gonzalez, P.; Alvarellos, J.E.; Chacon, E.

    1996-01-01

    In this paper we present nonlocal kinetic-energy functionals T[n] within the average density approximation (ADA) framework, which do not require any extra input when applied to any electron system and recover the exact kinetic energy and the linear response function of a homogeneous system. In contrast with previous ADA functionals, these present good behavior of the long-range tail of the exact weight function. The averaging procedure for the kinetic functional (averaging the Fermi momentum of the electron gas, instead of averaging the electron density) leads to a functional without numerical difficulties in the calculation of extended systems, and it gives excellent results when applied to atoms and jellium surfaces. copyright 1996 The American Physical Society

  3. Sulfide toxicity kinetics of a uasb reactor

    Directory of Open Access Journals (Sweden)

    D. R. Paula Jr.

    2009-12-01

    Full Text Available The effect of sulfide toxicity on kinetic parameters of anaerobic organic matter removal in a UASB (up-flow anaerobic sludge blanket reactor is presented. Two lab-scale UASB reactors (10.5 L were operated continuously during 12 months. The reactors were fed with synthetic wastes prepared daily using glucose, ammonium acetate, methanol and nutrient solution. One of the reactors also received increasing concentrations of sodium sulfide. For both reactors, the flow rate of 16 L.d-1 was held constant throughout the experiment, corresponding to a hydraulic retention time of 15.6 hours. The classic model for non-competitive sulfide inhibition was applied to the experimental data for determining the overall kinetic parameter of specific substrate utilization (q and the sulfide inhibition coefficient (Ki. The application of the kinetic parameters determined allows prediction of methanogenesis inhibition and thus the adoption of operating parameters to minimize sulfide toxicity in UASB reactors.

  4. Kinetics of hydrogen release from alloyed iron

    International Nuclear Information System (INIS)

    Gomozov, P.A.; Mogutnov, B.M.; Shvartsman, L.A.

    1977-01-01

    The kinetics of evolution of hydrogen from Armco-iron and alloys of iron with small amounts of carbon, phosphorus, sulfur, titanium, silicon and nickel was studied in the temperature range from 24 to 110 deg C. This process is described in terms of a kinetic equation which follows from the solution of the equation of diffusion with boundary conditions allowing for the rate of the chemical reaction on the surface of the specimen. A strong dependence is noted of the surface reaction on the presence of small amounts of alloying elements in the iron. The reaction of evolution of hydrogen from iron and its alloys in the temperature range from 24 to 110 deg C takes place in a combined diffusion-kinetic range

  5. Kinetics and thermodynamics of living copolymerization processes.

    Science.gov (United States)

    Gaspard, Pierre

    2016-11-13

    Theoretical advances are reported on the kinetics and thermodynamics of free and template-directed living copolymerizations. Until recently, the kinetic theory of these processes had only been established in the fully irreversible regime, in which the attachment rates are only considered. However, the entropy production is infinite in this regime and the approach to thermodynamic equilibrium cannot be investigated. For this purpose, the detachment rates should also be included. Inspite of this complication, the kinetics can be exactly solved in the regimes of steady growth and depolymerization. In this way, analytical expressions are obtained for the mean growth velocity, the statistical properties of the copolymer sequences, as well as the thermodynamic entropy production. The results apply to DNA replication, transcription and translation, allowing us to understand important aspects of molecular evolution.This article is part of the themed issue 'Multiscale modelling at the physics-chemistry-biology interface'. © 2016 The Author(s).

  6. Ladle Metallurgy Kinetics: Inclusion-Inclusion Reactions

    Science.gov (United States)

    Pistorius, P. Chris

    An example is presented to illustrate the joint effect of local reaction equilibria and mass transfer limitations, for reactions during ladle refining of steel. The example relies on some of the kinetic principles that David Robertson has employed to quantify many metallurgical processes. In calcium treatment of alumina inclusions in aluminum-killed steels, solid CaS forms as an intermediate reaction product. During subsequent reaction, CaS disappears and calcium aluminate forms; at the same time, aluminum and sulfur dissolve in the steel. Kinetic analysis shows that the rate of this reaction is not limited by mass transfer of dissolved aluminum and sulfur away from the reacting inclusions. The reaction rate is likely limited by transport of dissolved calcium. This example also illustrates the use of FactSage macros for kinetic modeling.

  7. Kinetics and spectroscopy of low temperature plasmas

    CERN Document Server

    Loureiro, Jorge

    2016-01-01

    This is a comprehensive textbook designed for graduate and advanced undergraduate students. Both authors rely on more than 20 years of teaching experience in renowned Physics Engineering courses to write this book addressing the students’ needs. Kinetics and Spectroscopy of Low Temperature Plasmas derives in a full self-consistent way the electron kinetic theory used to describe low temperature plasmas created in the laboratory with an electrical discharge, and presents the main optical spectroscopic diagnostics used to characterize such plasmas. The chapters with the theoretical contents make use of a deductive approach in which the electron kinetic theory applied to plasmas with basis on the electron Boltzmann equation is derived from the basic concepts of Statistical and Plasma Physics. On the other hand, the main optical spectroscopy diagnostics used to characterize experimentally such plasmas are presented and justified from the point of view of the Atomic and Molecular Physics. Low temperature plasmas...

  8. Kinetic Line Voronoi Operations and Their Reversibility

    DEFF Research Database (Denmark)

    Mioc, Darka; Anton, François; Gold, Christopher

    2010-01-01

    mechanisms and dynamic map visualisations. In order to use the reversibility within the kinetic Voronoi diagram of points and open oriented line segments, we need to assure that reversing the map commands will produce exactly the changes in the map equivalent to the previous map states. To prove...... that reversing the map update operations produces the exact reverse changes, we show an isomorphism between the set of complex operations on the kinetic Voronoi diagram of points and open oriented line segments and the sets of numbers of new / deleted Voronoi regions induced by these operations, and its...... explanation using the finite field of residual classes of integers modulo 5: F 5 = ℤ/5ℤ. We show also an isomorphism between the set of complex operations on the kinetic Voronoi diagram of points and open oriented line segments and the set of differences of new and deleted Quad-Edge edges induced...

  9. Evaluation of the biliary gallbladder emptying in patients with calcificant chronic pancreatitis through a scintilographic study with DISIDA Tc-99m

    International Nuclear Information System (INIS)

    Pedroso, Martha Regina Arcon

    1996-01-01

    The eventual relation between biliary lithiasis and chronic pancreatitis (CP) has been studied before but the research on the gallbladder involvement in chronic pancreatitis patients are rare, specially from a functional point of view. In order to study that, gallbladder emptying was evaluated in 11 patients with CP and the results were compared and analyzed statistically with the ones observed in 10 controls. This series exclude patients and controls who presented any kind of prior or current affection, or condition, that could interfere with the gastric or gallbladder emptying and the release of the entero pancreatic hormones. Gallbladder emptying was studied through the scintillographic method, using Tc-99m DISIDA, through the calculation of the ejection (EF) of the gallbladder (GB), at 30, 45 and 60 minutes. In the patients this evaluation was studied in two different periods of time with an interval of two to four weeks between them, without (CPWOP) and with (CPWP) the addition of pancreatic extract. The analyses of the results disclosed that the EF of GB at 60 minutes was significantly higher in the controls when compared tro chronic pancreatopaths. On the other hand, the EF of GB in these patients did not show any statistically significant differences after the administration of pancreatic extract. The results suggest that the delay in the gallbladder emptying does not depend exclusively on the eventual alteration in the intestinal phase of the gallbladder stimulation, but it probably also results from the association with other factors involved, as a mechanic factor, which depends on the compression of the main biliary tract through the chronic pathological process located in the cephalic portion of the pancreas. (author)

  10. Exercise: Kinetic considerations for gas exchange.

    Science.gov (United States)

    Rossiter, Harry B

    2011-01-01

    The activities of daily living typically occur at metabolic rates below the maximum rate of aerobic energy production. Such activity is characteristic of the nonsteady state, where energy demands, and consequential physiological responses, are in constant flux. The dynamics of the integrated physiological processes during these activities determine the degree to which exercise can be supported through rates of O₂ utilization and CO₂ clearance appropriate for their demands and, as such, provide a physiological framework for the notion of exercise intensity. The rate at which O₂ exchange responds to meet the changing energy demands of exercise--its kinetics--is dependent on the ability of the pulmonary, circulatory, and muscle bioenergetic systems to respond appropriately. Slow response kinetics in pulmonary O₂ uptake predispose toward a greater necessity for substrate-level energy supply, processes that are limited in their capacity, challenge system homeostasis and hence contribute to exercise intolerance. This review provides a physiological systems perspective of pulmonary gas exchange kinetics: from an integrative view on the control of muscle oxygen consumption kinetics to the dissociation of cellular respiration from its pulmonary expression by the circulatory dynamics and the gas capacitance of the lungs, blood, and tissues. The intensity dependence of gas exchange kinetics is discussed in relation to constant, intermittent, and ramped work rate changes. The influence of heterogeneity in the kinetic matching of O₂ delivery to utilization is presented in reference to exercise tolerance in endurance-trained athletes, the elderly, and patients with chronic heart or lung disease. © 2011 American Physiological Society.

  11. Current generation by the Kinetic Alfven wave

    International Nuclear Information System (INIS)

    Assis, A.S.

    1987-01-01

    The current generated and the efficiency of the shear Kinetic Alfven wave are obtained using a self-consistent quasilinear formulation. Also, the current generation by the monochromatic shear Kinetic Alfven wave introduced by Hasegawa is re-examined taking into account the nonresonant electrons. To obtain the RF current density at the level of the ohmic heating current density in a tokamak, the required external magnetic field is smaller than 0.1% of the DC magnetic field, and the parallel electric field (E 2 ), using the Lausanne-TCA-Tokamak parameters is of the order of 0.01 V cm -1 . (author) [pt

  12. Towards Free-Form Kinetic Structures

    DEFF Research Database (Denmark)

    Parigi, Dario; Kirkegaard, Poul Henning

    2012-01-01

    than the local displacements of elements. In the present paper the morphogenesis of KRS was included into a larger optimization procedure in order to translate overall design requirements into local displacements of elements. This method can be described now as a generalized procedure......Kinetic Reciprocal System (KRS) are a new kinetic system based on the principle of reciprocity [1] with internal pin-slot constraints. A morphogenetic procedure that can handle a set of many rigid bodies interconnected reciprocally with multiple pin-slot constraint was developed for the generation...

  13. Nonlinear wave interactions of kinetic sound waves

    Directory of Open Access Journals (Sweden)

    G. Brodin

    2015-08-01

    Full Text Available We reconsider the nonlinear resonant interaction between three electrostatic waves in a magnetized plasma. The general coupling coefficients derived from kinetic theory are reduced here to the low-frequency limit. The main contribution to the coupling coefficient we find in this way agrees with the coefficient recently presented in Annales Geophysicae. But we also deduce another contribution which sometimes can be important, and which qualitatively agrees with that of an even more recent paper. We have thus demonstrated how results derived from fluid theory can be improved and generalized by means of kinetic theory. Possible extensions of our results are outlined.

  14. Kinetic studies of elementary chemical reactions

    Energy Technology Data Exchange (ETDEWEB)

    Durant, J.L. Jr. [Sandia National Laboratories, Livermore, CA (United States)

    1993-12-01

    This program concerning kinetic studies of elementary chemical reactions is presently focussed on understanding reactions of NH{sub x} species. To reach this goal, the author is pursuing experimental studies of reaction rate coefficients and product branching fractions as well as using electronic structure calculations to calculate transition state properties and reaction rate calculations to relate these properties to predicted kinetic behavior. The synergy existing between the experimental and theoretical studies allow one to gain a deeper insight into more complex elementary reactions.

  15. Concepts of Modern Catalysis and Kinetics

    CERN Document Server

    Chorkendorff, I

    2003-01-01

    Until now, the literature has offered a rather limited approach to the use of fundamental kinetics and their application to catalytic reactions. Subsequently, this book spans the full range from fundamentals of kinetics and heterogeneous catalysis via modern experimental and theoretical results of model studies to their equivalent large-scale industrial production processes. The result is key knowledge for students at technical universities and professionals already working in industry. "...such an enterprise will be of great value to the community, to professionals as well as graduate an

  16. The coke drum thermal kinetic effects

    Energy Technology Data Exchange (ETDEWEB)

    Aldescu, Maria M.; Romero, Sim; Larson, Mel [KBC Advanced Technologies plc, Surrey (United Kingdom)

    2012-07-01

    The coke drum thermal kinetic dynamics fundamentally affect the coker unit yields as well as the coke product properties and unit reliability. In the drum the thermal cracking and polymerization or condensation reactions take place in a semi-batch environment. Understanding the fundamentals of the foaming kinetics that occur in the coke drums is key to avoiding a foam-over that could result in a unit shutdown for several months. Although the most dynamic changes with time occur during drum filling, other dynamics of the coker process will be discussed as well. KBC has contributed towards uncovering and modelling the complexities of heavy oil thermal dynamics. (author)

  17. Lower bound for the nuclear kinetic energy

    Energy Technology Data Exchange (ETDEWEB)

    Dehesa, J.S. (Granada Univ. (Spain). Dept. de Fisica Nuclear); Galvez, F.J. (Granada Univ. (Spain). Dept. de Fisica Teorica)

    1985-06-27

    We argue that the kinetic energy of a many-fermion system is bounded from below by Kqsup(-2/3)A sup(5/3) / , with K = 0.565 where q is the number of spin states available to each particle and sup(1/2) is the root mean square radius of the single-particle density. A simple lower bound for the nuclear kinetic energy is found. Numerical values of the bound for several nuclei are shown, and a comparison with some self-consistent calculations and some pseudo-empirical values is made.

  18. Kinetic theory of nonideal gases and nonideal plasmas

    CERN Document Server

    Klimontovich, Yu L

    2013-01-01

    Kinetic Theory of Nonideal Gases and Nonideal Plasmas presents the fundamental aspects of the kinetic theory of gases and plasmas. The book consists of three parts, which attempts to present some of the ideas, methods and applications in the study of the kinetic processes in nonideal gases and plasmas. The first part focuses on the classical kinetic theory of nonideal gases. The second part discusses the classical kinetic theory of fully ionized plasmas. The last part is devoted to the quantum kinetic theory of nonideal gases and plasmas. A concluding chapter is included, which presents a shor

  19. Antioxidant Capacity, Radical Scavenging Kinetics and Phenolic ...

    African Journals Online (AJOL)

    HP

    Results: Extract from Rhizophora mangle L and Krameria erecta displayed 5-fold higher antioxidant capacity than ascorbic acid with DPPH reduction values of 95.71 and 91 %, respectively. Anti-radical kinetic analysis and stoichiometric constant values suggest that the compounds responsible for antioxidant activity are ...

  20. Microstructure and transformation kinetics in bainitic steels

    NARCIS (Netherlands)

    Luzginova, N.V.

    2008-01-01

    With the aim of reaching a better understanding of the microstructure evolution and the overall phase transformation kinetics in hyper-eutectoid steels a commercial SAE 52100 bearing steel and 7 model alloys with different concentrations of chromium, cobalt and aluminum have been studied in this

  1. SHORT COMMUNICATION KINETICS AND MECHANISM OF ...

    African Journals Online (AJOL)

    Preferred Customer

    between the observed and calculated rate constants under varying experimental conditions. The activation parameters for the slow step were computed and discussed. Thermodynamic quantities were also determined. KEY WORDS: KEY WORDS: 2-Amino-1-butanol, Diperiodatoargentate(III), Kinetics, Reaction mechanism.

  2. The kinetic theory of open systems

    International Nuclear Information System (INIS)

    Klimontovich, Yu.L.

    2001-01-01

    This paper begins with a survey of recently obtained results in the statistical theory of open systems, including quantum open systems. Then the definition of the thermal flux in the kinetic theory is considered, further the collision nature of the Landau damping. Finally the Lamb shift and Bethe's formula are analyzed. (orig.)

  3. Kinetic analysis of boron carbide sintering

    International Nuclear Information System (INIS)

    Borchert, W.; Kerler, A.R.

    1975-01-01

    The kinetics of the sintering of boron carbide were investigated by shrinkage measurements with a high-temperature dilatometer under argon atmosphere in dependence on temperature, grain size, and pressure. The activation energies and the reaction mechanisms of the different stages of sintering were determined. (orig.) [de

  4. Kinetics of infrared stimulated luminescence from feldspars

    DEFF Research Database (Denmark)

    Jain, Mayank; Sohbati, Reza; Guralnik, Benny

    2015-01-01

    thermal and optical, of the infrared stimulated luminescence signal from feldspar. Based on the application of this model, it is concluded that different infra-red stimulated luminescence emissions (UV, blue, yellow and far-red) follow the same kinetics, and, therefore, involve participation of the same...... in feldspar. © 2015 Elsevier Ltd. All rights reserved....

  5. Analysis of microtubule assembly kinetics using turbidimetry.

    Science.gov (United States)

    Gaskin, Felicia

    2011-01-01

    Turbidity measurements are rapid and reliable methods to follow the effects of drugs, proteins, nucleotides, metals, and other factors on the assembly kinetics of tubulin into microtubules in vitro and have been in use since 1974. Improvements in spectrophotometers and software have resulted in the use of less protein, and more curves can be analyzed continuously and almost simultaneously.

  6. Adsorption Kinetics in Nanoscale Porous Coordination Polymers

    Energy Technology Data Exchange (ETDEWEB)

    Nune, Satish K.; Thallapally, Praveen K.; McGrail, Benard Peter; Annapureddy, Harsha V. R.; Dang, Liem X.; Mei, Donghai; Karri, Naveen; Alvine, Kyle J.; Olszta, Matthew J.; Arey, Bruce W.; Dohnalkova, Alice

    2015-10-07

    Nanoscale porous coordination polymers were synthesized using simple wet chemical method. The effect of various polymer surfactants on colloidal stability and shape selectivity was investigated. Our results suggest that the nanoparticles exhibited significantly improved adsorption kinetics compared to bulk crystals due to decreased diffusion path lengths and preferred crystal plane interaction.

  7. Non-equilibrium thermodynamics and physical kinetics

    CERN Document Server

    Bikkin, Halid

    2014-01-01

    This graduate textbook covers contemporary directions of non-equilibrium statistical mechanics as well as classical methods of kinetics. With one of the main propositions being to avoid terms such as "obviously" and "it is easy to show", this treatise is an easy-to-read introduction into this traditional, yet vibrant field.

  8. Untangling chemical kinetics through tangible and visual ...

    African Journals Online (AJOL)

    We propose that the use of elementary shapes (e.g. triangles, circles, squares) to represent different atoms in molecules facilitates the comprehension of chemical kinetics. Specifically, generation of “Concentration vs. Time” graphs rendered with the aid of tangible and/or pictorial representations of atoms using fixed ...

  9. Crystallization: Key thermodynamic, kinetic and hydrodynamic aspects

    Indian Academy of Sciences (India)

    This paper attempts to do that by critically reviewing published experimental and modelling studies on establishing and enhancing state-of-the-art thermodynamic, kinetic and hydrodynamic aspects of crystallization. Efforts are made to discuss and raise points for emerging modelling tools needed for a flexible design and ...

  10. Chemical Dosing and First-Order Kinetics

    Science.gov (United States)

    Hladky, Paul W.

    2011-01-01

    College students encounter a variety of first-order phenomena in their mathematics and science courses. Introductory chemistry textbooks that discuss first-order processes, usually in conjunction with chemical kinetics or radioactive decay, stop at single, discrete dose events. Although single-dose situations are important, multiple-dose events,…

  11. Antioxidant Capacity, Radical Scavenging Kinetics and Phenolic ...

    African Journals Online (AJOL)

    Antioxidant Capacity, Radical Scavenging Kinetics and Phenolic Profile of Methanol Extracts of Wild Plants of Southern Sonora, Mexico. EF Moran-Palacio, LA Zamora-Álvarez, NA Stephens-Camacho, GA Yáñez- Farías, A Virgen-Ortiz, O Martínez-Cruz, JA Rosas-Rodríguez ...

  12. Kinetics of Oxidation of Fe–6Si

    Czech Academy of Sciences Publication Activity Database

    Lashin, Abdel Rahman; Schneeweiss, Oldřich; Svoboda, Milan

    2008-01-01

    Roč. 69, č. 5-6 (2008), s. 359-374 ISSN 0030-770X R&D Projects: GA AV ČR IAA1041404 Institutional research plan: CEZ:AV0Z20410507 Keywords : iron silicon * Mössbauer spectroscopy * XRD * iron oxides * oxidation kinetics Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.359, year: 2008

  13. KINETICS AND MECHANISM OF PRUSSIAN BLUE FORMATION ...

    African Journals Online (AJOL)

    The kinetics of reaction between ferrocyanide and ferric ions under acidic conditions was studied at fixed ionic strength (0.1 M) and (25 ± 0.1) oC by using the stopped flow technique, under limiting conditions of [ferrocyanide] and with other reactants in excess. The reaction had first-order dependence on ferrocyanide, Fe(III) ...

  14. Crystallization: Key thermodynamic, kinetic and hydrodynamic aspects

    Indian Academy of Sciences (India)

    understanding of the thermodynamic, kinetic and hydrodynamic aspects of the design methodologies are not yet well ...... The mixer design is finalized with mechanical design of the shaft, impeller blade thickness, baffle thickness and supports, ...... PhD-Thesis, Delft University of Technol- ogy, Delft. Dimonte J E, Szutowski H ...

  15. A kinetic model of zircon thermoluminescence

    NARCIS (Netherlands)

    Turkin, A.A.; Es, H.J. van; Vainshtein, D.I.; Hartog, H.W. den

    A kinetic model of zircon thermoluminescence (TL) has been constructed to simulate the processes and stages relevant to thermoluminescent dating such as: filling of electron and hole traps during the excitation stage both for natural and laboratory irradiation; the time dependence of fading after

  16. Superradiance kinetics of a. gamma. -ray laser

    Energy Technology Data Exchange (ETDEWEB)

    Andreev, A.V.

    1977-04-01

    An analysis is made of the kinetics of a single-pass mirror-free ..gamma..-ray laser. The conditions governing the operation of this laser are obtained. The possibility of Dicke superradiance in the ..gamma..-ray range is estimated. The analysis is carried out for single-mode emission from a system of two-level nuclei.

  17. Enzyme kinetic characterization of protein tyrosine phosphatases

    DEFF Research Database (Denmark)

    Peters, Günther H.J.; Branner, S.; Møller, K. B.

    2003-01-01

    Protein tyrosine phosphatases (PTPs) play a central role in cellular signaling processes, resulting in an increased interest in modulating the activities of PTPs. We therefore decided to undertake a detailed enzyme kinetic evaluation of various transmembrane and cytosolic PTPs (PTPalpha, PTPbeta...

  18. COMPARATIVE ANALYSIS OF SOME EXISTING KINETIC MODELS ...

    African Journals Online (AJOL)

    The biosorption of three heavy metal ions namely; Zn2+, Cu2+ and Mn2+ using five microorganisms namely; Bacillus circulans, Pseudomonas aeruginosa, Staphylococcus xylosus, Streptomyces rimosus and Yeast (Saccharomyces sp.) were studied. In this paper, the effectiveness of six existing and two proposed kinetic ...

  19. A MODEL FOR POSTRADIATION STEM CELL KINETICS,

    Science.gov (United States)

    In polycythemic rats observed for 17 days postradiation (300 R, 250 KVP X-rays) it was noted that stem cell release diminished to 8 percent of the...correlate these findings with a kinetic model of erythropoiesis. It was suggested that the initial depression in stem cell release might be due to cellular

  20. Copper laser diagnostics and kinetics support

    International Nuclear Information System (INIS)

    1981-12-01

    In the effort MSNW participated with the LINL copper-Vapor Laser Program by providing a useful plasma diagnostic for interpretation of Copper-vapor laser kinetics. MSNW developed and delivered a pulsed interferometric diagnostic package to LLNL. Moreover MSNW provided personal services at the request and direction of LLL in the implementation of the diagnostic and interpretation of the data

  1. Kinetics of asphaltene precipitation from crude oils

    Energy Technology Data Exchange (ETDEWEB)

    Maqbool, T.; Hussein, I.A.; Fogler, H.S. [Michigan Univ., Ann Arbor (United States). Dept. of Chemical Engineering

    2008-07-01

    The kinetics of asphaltene precipitation from crude oils was investigated using n-alkane precipitants. Recent studies have shown that there is a kinetic phenomenon associated with asphaltene precipitation. This study showed that the time needed to precipitate the asphaltenes can vary from a few minutes to several months, depending on the amount of n-alkane precipitant added. As such, the onset of asphaltene precipitation is a function of the concentration of precipitant and time. A technique to quantify the amount of asphaltenes precipitated as a function of time and precipitant concentration was presented. This study also investigated the kinetic effects caused by various precipitants. Optical microscopy was used to monitor the growth of asphaltene aggregates with time. Refractive index measurements provided further insight into the kinetics of asphaltene precipitation. Polarity based fractionation and dielectric constant measurements were used to compare the nature of asphaltenes precipitated early in the precipitation process with the asphaltenes precipitated at later times. It was concluded that asphaltenes precipitating at different times from the same crude oil-precipitant mixture are different from one another. 3 refs.

  2. Collapse of a Bose gas: Kinetic approach

    Indian Academy of Sciences (India)

    Abstract. We have analytically explored the temperature dependence of critical number of par- ticles for the collapse of a harmonically trapped attractively interacting Bose gas below the condensation point by introducing a kinetic approach within the Hartree–Fock approximation. The temperature dependence obtained by ...

  3. Transformation kinetics of mixed polymeric substrates under ...

    African Journals Online (AJOL)

    Transformation kinetics of mixed polymeric substrates under transitory conditions by Aspergillus niger. ... Abstract. A mixture of polymeric substrates (simulating a complex wastewater) was transformed under sewer conditions and aerobiosis by Aspergillus niger in a tanks-in-series reactor at a hydraulic retention time of 14 h.

  4. Application of dhurrin for kinetics and thermodynamic ...

    African Journals Online (AJOL)

    The entropy change (ΔS) increased with enzyme purity from 0.588 J/mol.deg. to 1.4625Jmol degree. The enthalpy change KJ/mol followed the same pattern whereby increases influenced by enzyme purity ranged from 1892 KJ/mol to 13104KJ/mol. Keywords: kinetics, thermodynamic, characterization, dhurrin, genetically ...

  5. Kinetics of fibrilar aggregation of food proteins

    NARCIS (Netherlands)

    Arnaudov, L.N.

    2005-01-01

    In this thesis we study the kinetics of fibrilar aggregation of two model proteins widely used in the food industry -b-lactoglobulin (b-lg) and hen

  6. Platelet kinetics: the state of the art

    International Nuclear Information System (INIS)

    Heyns, A. duP

    1984-01-01

    In this paper an overview of the state of the art of platelet kinetics 1982 is presented. The subjects considered include a discussion of the advantages and disadvantages of some of the many radionuclide platelet labels, viz 51 Cr, 111 In, focussing briefly on models for analysis of platelets survival. (Auth.)

  7. Kinetics of dehydration of zirconium disulfate tetrahydrate

    International Nuclear Information System (INIS)

    Prozorovskaya, Z.N.; Erokhina, O.I.; Spitsyn, V.I.

    1977-01-01

    The dehydration process of zirconium disulphate tetrahydrate has been studied by the methods of isothermal and polythermal kinetics. The rate constants of dehydration have been determined in the temperature range from 170 to 210 deg C. The apparent energy values have been calculated under polythermal and isothermal conditions in air and under isothermal conditions in vacuum

  8. Analysis of lipid peroxidation kinetics. I

    DEFF Research Database (Denmark)

    Doktorov, Alexander B.; Lukzen, Nikita N.; Pedersen, Jørgen Boiden

    2008-01-01

    concentrations of reactants or different ways of initiating the re-  action. Nor has it been possible to predict the time dependence of the  products. The reason for these problems is the complicated structure  of the kinetic scheme, which includes a chain reaction. In this work  we perform an in depth analysis...

  9. Kinetic studies of stress-corrosion cracking

    Science.gov (United States)

    Noronha, P. J.

    1977-01-01

    Use of time-to-failure curves for stress-corrosion cracking processes may lead to incorrect estimates of structural life, if material is strongly dependent upon prestress levels. Technique characterizes kinetics of crackgrowth rates and intermediate arrest times by load-level changes.

  10. Metal dusting: kinetically or thermodynamically controlled?

    NARCIS (Netherlands)

    Hermse, C.G.M.

    2011-01-01

    The current paper determines whether the rate of the metal dusting reaction is kinetically or thermodynamically controlled at 600 degrees Celsius. This is done by varying the gas composition, specifically the CO partial pressure and the carbon activity, and comparing the degradation rates of alloy

  11. Solution Kinetics Database on the Web

    Science.gov (United States)

    SRD 40 NDRL/NIST Solution Kinetics Database on the Web (Web, free access)   Data for free radical processes involving primary radicals from water, inorganic radicals and carbon-centered radicals in solution, and singlet oxygen and organic peroxyl radicals in various solvents.

  12. students' conceptions and misconceptions in chemical kinetics

    African Journals Online (AJOL)

    IICBA01

    40 items ... Approach to Teaching and Learning (SATL) in preparing lesson delivery for chemical concepts including chemical kinetics [9, 10]. In SATLC technique the concepts are positioned in such a way that the relations between a series of ideas and issues are made logical. The basic goal of this approach is the ...

  13. Norepinephrine kinetics during insulin-induced hypoglycemia

    DEFF Research Database (Denmark)

    Hilsted, J; Christensen, N J; Larsen, S

    1985-01-01

    Norepinephrine (NE) kinetics (plasma appearance rate, clearance, and forearm extraction) were measured during insulin-induced hypoglycemia in six healthy subjects. NE clearance did not change during hypoglycemia, indicating that the increase in plasma NE during hypoglycemia is due to an increased...

  14. A kinetic equation for irreversible aggregation

    International Nuclear Information System (INIS)

    Zanette, D.H.

    1990-09-01

    We introduce a kinetic equation for describing irreversible aggregation in the ballistic regime, including velocity distributions. The associated evolution for the macroscopic quantities is studied, and the general solution for Maxwell interaction models is obtained in the Fourier representation. (author). 23 refs

  15. Aircraft Measurements of Atmospheric Kinetic Energy Spectra

    DEFF Research Database (Denmark)

    Lundtang Petersen, Erik; Lilly, D. K.

    1983-01-01

    Wind velocity data obtained from a jet airliner are used to construct kinetic energy spectra over the range of wavelengths from 2.5 to 2500 km. The spectra exhibit an approximate -5/3 slope for wavelengths of less than about 150 km, steepening to about -2.2 at larger scales. These results support...

  16. Transformation kinetics of mixed polymeric substrates under ...

    African Journals Online (AJOL)

    Admin

    The residual biomasses of fungi used in industries to produce enzymes are stocked in landfill nowadays, but they could serve as inoculums for pretreatment. The aims of this study were (i) to determine the kinetics of the pretreatment under transitory conditions of a synthetic wastewater containing a mixture of starch and.

  17. Kinetics of plasma flow in recycling region

    International Nuclear Information System (INIS)

    Kraheninnikov, S.I.; Gosudarstvennyj Komitet po Ispol'zovaniyu Atomnoj Ehnergii SSSR, Moscow; Chodura, R.

    1994-01-01

    Kinetics of plasma flow in tokamak SOL plasma recycling region for large ratio of Coulomb mean free path, λ T , to neutral recycling length, L N , is considered. Such regimes are quite typical for both current tokamaks and ITER-like reactor conditions and can not be treated by fluid approximation. (orig.)

  18. The kinetically dominated quasar 3C 418

    Science.gov (United States)

    Punsly, Brian; Kharb, Preeti

    2017-06-01

    The existence of quasars that are kinetically dominated, where the jet kinetic luminosity, Q, is larger than the total (infrared to X-ray) thermal luminosity of the accretion flow, Lbol, provides a strong constraint on the fundamental physics of relativistic jet formation. Since quasars have high values of Lbol by definition, only ˜10 kinetically dominated quasars (with \\overline{Q}/L_{bol}>1) have been found, where \\overline{Q} is the long-term time-averaged jet power. We use low-frequency (151 MHz-1.66 GHz) observations of the quasar 3C 418 to determine \\overline{Q}≈ 5.5 ± 1.3 × 10^{46} {erg s^{-1}}. Analysis of the rest-frame ultraviolet spectrum indicates that this equates to 0.57 ± 0.28 times the Eddington luminosity of the central supermassive black hole and \\overline{Q}/L_{bol} ≈ 4.8 ± 3.1, making 3C 418 one of the most kinetically dominated quasars found to date. It is shown that this maximal \\overline{Q}/L_{bol} is consistent with models of magnetically arrested accretion of jet production in which the jet production reproduces the observed trend of a decrement in the extreme ultraviolet continuum as the jet power increases. This maximal condition corresponds to an almost complete saturation of the inner accretion flow with vertical large-scale magnetic flux (maximum saturation).

  19. Thermodynamic and kinetic modelling: creep resistant materials

    DEFF Research Database (Denmark)

    Hald, John; Korcakova, L.; Danielsen, Hilmar Kjartansson

    2008-01-01

    The use of thermodynamic and kinetic modelling of microstructure evolution in materials exposed to high temperatures in power plants is demonstrated with two examples. Precipitate stability in martensitic 9–12%Cr steels is modelled including equilibrium phase stability, growth of Laves phase...

  20. Kinetic model for polyhydroxybutyrate (PHB) production by ...

    African Journals Online (AJOL)

    A kinetic model that describes microbial growth, biopolymer production and substrate consumption is used to predict the performance of batch fermentation of Hydrogenophaga pseudoflava. H. pseudoflava DSMZ 1034 is useful in synthesizing polyhydroxyalkanoates (PHAs).The experimental data was also fitted with the ...

  1. Crystallization: Key thermodynamic, kinetic and hydrodynamic aspects

    Indian Academy of Sciences (India)

    In spite of the wide-spread use of crystallization, a clear understanding of the thermodynamic, kinetic and hydrodynamic aspects of the design methodologies are not yet well established. More often than not crystallization is still considered an art especially in fine-chemicals, pharmaceuticals and life-sciences sector.

  2. Thermodynamic, kinetic and mechanistic investigations of ...

    Indian Academy of Sciences (India)

    Abstract. The kinetics of oxidation of piperazine by the copper complex, diperiodatocuprate(III) in alkaline medium was studied at 298 K, at an ionic strength of 2.0 x 10−2 mol dm−3. The reaction between piperazine and diperiodatocuprate(III) in aqueous alkaline medium exhibited 1:2 stoichiometry. The oxidation products.

  3. KINETICS OF THE OXIDATION OF VITAMIN C

    Directory of Open Access Journals (Sweden)

    Sitti Rahmawati

    2012-12-01

    Full Text Available Vitamin C or ascorbic acid is needed by the human body but it is already damaged by the rise in temperature due to be oxidized to L-dehydroascorbic acid. This research aims to determine the kinetics of oxidation of ascorbic acid due to an increase if temperature (40-80 °C and to design an ascorbic acid oxidation reaction laboratory module to be applied in the senior high school reaction kinetics curriculum. The determination of the kinetics of the oxidation of ascorbic acid applies the integral and half-change time methods, while the concentration of the remained ascorbic acid in sixty minute intervals is determined by iodimetric titration method. Decomposition of ascorbic acid was measured at 40, 50, 60, 70 and 80 °C. The results of this research indicate that at 40, 50, 60, 70 and 80 °C the kinetics of the oxidation of ascorbic acid is a first-order reaction with rate constants of 4.55 x 10-4, 5.85 x 10-4, 8.4 x 10-4, 1.1 x 10-3 and 1.015 x 10-3 min-1, respectively. Pre-exponential factor or the frequency of collisions is a factor which is a measure of the collision rate. The activation energy and the pre-exponential factor for the oxidation of ascorbic acid were found to be 20.73 kJ.mol-1 and 1.372 min-1. The procedure used in this study was modified into a laboratory module will be applied in the teaching of reaction kinetics at the senior high school level.

  4. Reflected kinetics model for nuclear space reactor kinetics and control scoping calculations

    Energy Technology Data Exchange (ETDEWEB)

    Washington, K.E.

    1986-05-01

    The objective of this research is to develop a model that offers an alternative to the point kinetics (PK) modelling approach in the analysis of space reactor kinetics and control studies. Modelling effort will focus on the explicit treatment of control drums as reactivity input devices so that the transition to automatic control can be smoothly done. The proposed model is developed for the specific integration of automatic control and the solution of the servo mechanism problem. The integration of the kinetics model with an automatic controller will provide a useful tool for performing space reactor scoping studies for different designs and configurations. Such a tool should prove to be invaluable in the design phase of a space nuclear system from the point of view of kinetics and control limitations.

  5. Reflected kinetics model for nuclear space reactor kinetics and control scoping calculations

    International Nuclear Information System (INIS)

    Washington, K.E.

    1986-05-01

    The objective of this research is to develop a model that offers an alternative to the point kinetics (PK) modelling approach in the analysis of space reactor kinetics and control studies. Modelling effort will focus on the explicit treatment of control drums as reactivity input devices so that the transition to automatic control can be smoothly done. The proposed model is developed for the specific integration of automatic control and the solution of the servo mechanism problem. The integration of the kinetics model with an automatic controller will provide a useful tool for performing space reactor scoping studies for different designs and configurations. Such a tool should prove to be invaluable in the design phase of a space nuclear system from the point of view of kinetics and control limitations

  6. Degradation kinetics of metronidazole and its mutual prodrug with ...

    African Journals Online (AJOL)

    Dr Renu Chadha

    Corresponding author, Tel: 91-172-2534104, Email: ... kinetic parameters of chemical reactions. It's indifferent to physical state of material and thus, this ...... Kinetics of degradation of diclofenac sodium in aqueous solution determined by a calorimetric ...

  7. Alkylation of Chlorobenzene. An Experiment Illustrating Kinetic versus Thermodynamic Control.

    Science.gov (United States)

    Kolb, Kenneth; And Others

    1988-01-01

    Describes an experiment which illustrates the kinetic versus thermodynamic control of chemical reactions for organic chemistry students. Considers the laboratory procedures including the isolation of both the kinetic and thermodynamic products. (CW)

  8. Lactate Kinetics during Exercise in Chronic Obstructive Pulmonary Disease

    Directory of Open Access Journals (Sweden)

    François Maltais

    1997-01-01

    Full Text Available OBJECTIVES: To examine whether the lactate kinetics during exercise are abnormal in patients with chronic obstructive pulmonary disease (COPD and to evaluate the relationship of lactate kinetics with functional status.

  9. Kinetic modelling of the Maillard reaction between proteins and sugars

    NARCIS (Netherlands)

    Brands, C.M.J.

    2002-01-01

    Keywords: Maillard reaction, sugar isomerisation, kinetics, multiresponse modelling, brown colour formation, lysine damage, mutagenicity, casein, monosaccharides, disaccharides, aldoses, ketoses

    The aim of this thesis was to determine the kinetics of the Maillard reaction between

  10. New Methods for Processing and Quantifying VO2 Kinetics to Steady State: VO2 Onset Kinetics

    Directory of Open Access Journals (Sweden)

    Craig R. McNulty

    2017-09-01

    Full Text Available Current methods of oxygen uptake (VO2 kinetics data handling may be too simplistic for the complex physiology involved in the underlying physiological processes. Therefore, the aim of this study was to quantify the VO2 kinetics to steady state across the full range of sub-ventilatory threshold work rates, with a particular focus on the VO2 onset kinetics. Ten healthy, moderately trained males participated in five bouts of cycling. Each bout involved 10 min at a percentage of the subject's ventilation threshold (30, 45, 60, 75, 90% from unloaded cycling. The VO2 kinetics was quantified using the conventional mono-exponential time constant (tau, τ, as well as the new methods for VO2 onset kinetics. Compared to linear modeling, non-linear modeling caused a deterioration of goodness of fit (main effect, p < 0.001 across all exercise intensities. Remainder kinetics were also improved using a modified application of the mono-exponential model (main effect, p < 0.001. Interestingly, the slope from the linear regression of the onset kinetics data is similar across all subjects and absolute exercise intensities, and thereby independent of subject fitness and τ. This could indicate that there are no functional limitations between subjects during this onset phase, with limitations occurring for the latter transition to steady state. Finally, the continuing use of mono-exponential modeling could mask important underlying physiology of more instantaneous VO2 responses to steady state. Consequently, further research should be conducted on this new approach to VO2 onset kinetics.

  11. The Role of Target Binding Kinetics in Drug Discovery.

    Science.gov (United States)

    Guo, Dong; Heitman, Laura H; IJzerman, Adriaan P

    2015-11-01

    Traditionally structure-activity/affinity relationships (SAR) have dominated research in medicinal chemistry. However, structure-kinetics relationships (SKR) can be very informative too. In this viewpoint we explore the molecular determinants of binding kinetics and discuss challenges for future binding kinetics studies. A scheme for future kinetics-directed drug design and discovery is also proposed. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. Kinetics of Pressurized Water Reactors with Hot or Cold Moderators

    Energy Technology Data Exchange (ETDEWEB)

    Norinder, O.

    1960-11-15

    The set of neutron kinetic equations developed in this report permits the use of long integration steps during stepwise integration. Thermal relations which describe the transfer of heat from fuel to coolant are derived. The influence upon the kinetic behavior of the reactor of a number of parameters is studied. A comparison of the kinetic properties of the hot and cold moderators is given.

  13. Variation of kinetic isotope effect in multiple proton transfer reactions

    Indian Academy of Sciences (India)

    Proton transfer; promoter modes; kinetic isotope effect. 1. Introduction. Kinetic isotope effect (KIE) is the dependence of the rate constant on the mass of the isotope of the atom in a chemical reaction. The primary kinetic isotope effect is the KIE when the bonds connecting that atom to the rest of the molecular frame are broken ...

  14. Stochastic optimization-based study of dimerization kinetics

    Indian Academy of Sciences (India)

    Keywords. Stochastic optimization; dimerization kinetics; sensitivity analysis; stochastic simulation algorithm; probability distribution function. ... To this end, we study dimerization kinetics of protein as a model system. We follow the dimerization kinetics using a stochastic simulation algorithm and combine it with three ...

  15. Stochastic optimization-based study of dimerization kinetics

    Indian Academy of Sciences (India)

    Abstract. We investigate the potential of numerical algorithms to decipher the kinetic parameters involved in multi-step chemical reactions. To this end, we study dimerization kinetics of protein as a model system. We follow the dimerization kinetics using a stochastic simulation algorithm and combine it with three different.

  16. KINETICS OF QUERCETIN NITRATIO N BY HORSERADISH PEROXIDASE

    Directory of Open Access Journals (Sweden)

    Andrija Šmelcerović

    2013-03-01

    Full Text Available In this study we investigated the kinetics of the nitration of quercetin by horseradish peroxidase. Quercetin nitration reaction was followed by recording the spectral changes over the time at 380 nm. The reaction rate increases with increasing of the quercetin concentration and follows the Michaelis-Menten type kinetics. Kinetic parameters of the studied enzymatic reaction were determined.

  17. Kinetic Study of Calcination of Jakura Limestone Using Power Rate ...

    African Journals Online (AJOL)

    investigation into kinetics of calcinations of some large commercial deposits of limestone in Nigeria. The study is aimed at finding kinetic parameters for the purpose of energy saving, lime kiln design, modeling and simulation of lime kiln. In this study, kinetic of Jakura limestone calcination process using power rate law has ...

  18. A mathematical model on germinal center kinetics andtermination

    DEFF Research Database (Denmark)

    Kesmir, Can; De Boer, R.J.

    1999-01-01

    We devise a mathematical model to study germinal center (GC) kinetics. Earlier models for GC kinetics areextended by explicitly modeling 1) the cell division history of centroblasts, 2) the Ag uptake by centrocytes,and 3) T cell dynamics. Allowing for T cell kinetics and T-B cell interactions, we...

  19. Kinetic aspects of the Maillard reaction: a critical review

    NARCIS (Netherlands)

    Boekel, van M.A.J.S.

    2001-01-01

    The literature concerning the kinetics of the Maillard reaction was critically discussed according to the initial, intermediate and advanced stages, as this is the way the Maillard reaction is traditionally analysed. For each stage, a division is made between simple kinetics and complex kinetics.

  20. Modelling dimercaptosuccinic acid (DMSA) plasma kinetics in humans

    NARCIS (Netherlands)

    van Eijkeren, Jan C H; Olie, J Daniël N; Bradberry, Sally M; Vale, J Allister; de Vries, Irma; Meulenbelt, Jan; Hunault, Claudine C

    2016-01-01

    CONTEXT: No kinetic models presently exist which simulate the effect of chelation therapy on lead blood concentrations in lead poisoning. OBJECTIVE: Our aim was to develop a kinetic model that describes the kinetics of dimercaptosuccinic acid (DMSA; succimer), a commonly used chelating agent, that

  1. Athermal kinetics in low alloy steels

    International Nuclear Information System (INIS)

    Leiva, Jorge A Vega; Valencia Morales, Eduardo; Villar Cociña, Ernesto; Hernández Ruiz, Jesús; Donis, Carlos

    2008-01-01

    Athermic analyses for the kinetic study of the reactions in the solid state are preferred because they consume much less experimental work time than the isothermal tests, and lead to more accurate calculations of the energies of activation of reactions that have occurred. In the present work are required conditions where you can apply the equation of speed of an athermal reaction in a low alloy in solid steel. From records of steel (AISI 1050) dilatometric triples were calculated kinetics (E, Ko, n) that characterize the reactions that occurred during the tempering of samples using different methods of iso conversion, one of which is a new modification of the method of Friedman. Also, has shown that during the formation of carbide Epsilon in the first stage of the tempering has occurred a saturation of sites, which validates the use of some methods. Finally, the orders of the reactions occurred during tempering of steel studied treatment are calculated.

  2. Luminescence kinetics of porous silicon: fluctuation approach

    CERN Document Server

    Bondarev, V N

    2001-01-01

    Theoretical interpretation of the kinetics of the photoluminescence (PL), caused by the tunnel radiative recombination of the photoexcited electron and hole, localized on the crystallite/matrix interface, is given on the basis of the notions on the porous silicon structure as an incidental totality of the Si nanodimensional crystallites, submerged into the SiO sub 2 matrix. The relatively slow (by the stretched exponential type) time drop in the PL intensity is the results of averaging the intensity in each PL elementary act by the electron and hole mutual disposition and by the crystallite dimensions. The good quantitative description of the low-temperature experiments may be obtained through the proposed approach both by the PL kinetics and time evolution of the porous silicon PL spectrum

  3. Processes of aggression described by kinetic method

    Science.gov (United States)

    Aristov, V. V.; Ilyin, O.

    2014-12-01

    In the last decades many investigations have been devoted to theoretical models in new areas concerning description of different biological, sociological and historical processes. In the present paper we suggest a model of the Nazi Germany invasion of Poland, France and USSR based on the kinetic theory. We model this process with the Cauchy boundary problem for the two-element kinetic equations with spatial initial conditions. The solution of the problem is given in the form of traveling wave. The propagation velocity of a frontline depends on the quotient between initial forces concentrations. Moreover it is obtained that the general solution of the model can be expressed in terms of quadratures and elementary functions. Finally it is shown that the frontline velocities are complied with the historical data.

  4. Energy transfer and kinetics in mechanochemistry.

    Science.gov (United States)

    Chen, Zhiliang; Lu, Shengyong; Mao, Qiongjing; Buekens, Alfons; Wang, Yuting; Yan, Jianhua

    2017-11-01

    Mechanochemistry (MC) exerts extraordinary degradation and decomposition effects on many chlorinated, brominated, and even fluorinated persistent organic pollutants (POPs). However, its application is still limited by inadequate study of its reaction kinetic aspects. In the present work, the ball motion and energy transfer in planetary ball mill are investigated in some detail. Almost all milling parameters are summarised in a single factor-total effective impact energy. Furthermore, the MC kinetic between calcium oxide/Al and hexachlorobenzene is well established and modelled. The results indicate that total effective impact energy and reagent ratio are the two factors sufficient for describing the MC degradation degree of POPs. The reaction rate constant only depends on the chemical properties of reactants, so it could be used as an important index to appraise the quality of MC additives. This model successfully predicts the reaction rate for different operating conditions, indicating that it could be suitably applied for conducting MC reactions in other reactors.

  5. A MATLAB toolbox for structural kinetic modeling.

    Science.gov (United States)

    Girbig, Dorothee; Selbig, Joachim; Grimbs, Sergio

    2012-10-01

    Structural kinetic modeling (SKM) enables the analysis of dynamical properties of metabolic networks solely based on topological information and experimental data. Current SKM-based experiments are hampered by the time-intensive process of assigning model parameters and choosing appropriate sampling intervals for Monte-Carlo experiments. We introduce a toolbox for the automatic and efficient construction and evaluation of structural kinetic models (SK models). Quantitative and qualitative analyses of network stability properties are performed in an automated manner. We illustrate the model building and analysis process in detailed example scripts that provide toolbox implementations of previously published literature models. The source code is freely available for download at http://bioinformatics.uni-potsdam.de/projects/skm. girbig@mpimp-golm.mpg.de.

  6. Processes of aggression described by kinetic method

    Energy Technology Data Exchange (ETDEWEB)

    Aristov, V. V.; Ilyin, O. [Dorodnicyn Computing Centre of Russian Academy of Sciences, Vavilova str. 40, Moscow, 119333 (Russian Federation)

    2014-12-09

    In the last decades many investigations have been devoted to theoretical models in new areas concerning description of different biological, sociological and historical processes. In the present paper we suggest a model of the Nazi Germany invasion of Poland, France and USSR based on the kinetic theory. We model this process with the Cauchy boundary problem for the two-element kinetic equations with spatial initial conditions. The solution of the problem is given in the form of traveling wave. The propagation velocity of a frontline depends on the quotient between initial forces concentrations. Moreover it is obtained that the general solution of the model can be expressed in terms of quadratures and elementary functions. Finally it is shown that the frontline velocities are complied with the historical data.

  7. Chemical kinetic functional sensitivity analysis: Elementary sensitivities

    International Nuclear Information System (INIS)

    Demiralp, M.; Rabitz, H.

    1981-01-01

    Sensitivity analysis is considered for kinetics problems defined in the space--time domain. This extends an earlier temporal Green's function method to handle calculations of elementary functional sensitivities deltau/sub i//deltaα/sub j/ where u/sub i/ is the ith species concentration and α/sub j/ is the jth system parameter. The system parameters include rate constants, diffusion coefficients, initial conditions, boundary conditions, or any other well-defined variables in the kinetic equations. These parameters are generally considered to be functions of position and/or time. Derivation of the governing equations for the sensitivities and the Green's funciton are presented. The physical interpretation of the Green's function and sensitivities is given along with a discussion of the relation of this work to earlier research

  8. Hypocoercivity for linear kinetic equations conserving mass

    KAUST Repository

    Dolbeault, Jean

    2015-02-03

    We develop a new method for proving hypocoercivity for a large class of linear kinetic equations with only one conservation law. Local mass conservation is assumed at the level of the collision kernel, while transport involves a confining potential, so that the solution relaxes towards a unique equilibrium state. Our goal is to evaluate in an appropriately weighted $ L^2$ norm the exponential rate of convergence to the equilibrium. The method covers various models, ranging from diffusive kinetic equations like Vlasov-Fokker-Planck equations, to scattering models or models with time relaxation collision kernels corresponding to polytropic Gibbs equilibria, including the case of the linear Boltzmann model. In this last case and in the case of Vlasov-Fokker-Planck equations, any linear or superlinear growth of the potential is allowed. - See more at: http://www.ams.org/journals/tran/2015-367-06/S0002-9947-2015-06012-7/#sthash.ChjyK6rc.dpuf

  9. Kinetics of Peptide Folding in Lipid Membranes

    Science.gov (United States)

    Oh, Kwang-Im; Smith-Dupont, Kathryn B.; Markiewicz, Beatrice N.; Gai, Feng

    2015-01-01

    Despite our extensive understanding of water-soluble protein folding kinetics, much less is known about the folding dynamics and mechanisms of membrane proteins. However, recent studies have shown that for relatively simple systems, such as peptides that form a transmembrane α-helix, helical dimer, or helix-turn-helix, it is possible to assess the kinetics of several important steps, including peptide binding to the membrane from aqueous solution, peptide folding on the membrane surface, helix insertion into the membrane, and helix-helix association inside the membrane. Herein, we provide a brief review of these studies and also suggest new initiation and probing methods that could lead to improved temporal and structural resolution in future experiments. PMID:25808575

  10. Accelerating search kinetics by following boundaries

    Science.gov (United States)

    Calandre, T.; Bénichou, O.; Voituriez, R.

    2014-06-01

    We derive exact expressions of the mean first-passage time to a bulk target for a random searcher that performs boundary-mediated diffusion in a circular domain. Although nonintuitive for bulk targets, it is found that boundary excursions, if fast enough, can minimize the search time. A scaling analysis generalizes these findings to domains of arbitrary shapes and underlines their robustness. Overall, these results provide a generic mechanism of optimization of search kinetics in interfacial systems, which could have important implications in chemical physics. In the context of animal behavior sciences, it shows that following the boundaries of a domain can accelerate a search process, and therefore suggests that thigmotactism could be a kinetically efficient behavior.

  11. Kinetic Titration Series with Biolayer Interferometry

    Science.gov (United States)

    Frenzel, Daniel; Willbold, Dieter

    2014-01-01

    Biolayer interferometry is a method to analyze protein interactions in real-time. In this study, we illustrate the usefulness to quantitatively analyze high affinity protein ligand interactions employing a kinetic titration series for characterizing the interactions between two pairs of interaction patterns, in particular immunoglobulin G and protein G B1 as well as scFv IC16 and amyloid beta (1–42). Kinetic titration series are commonly used in surface plasmon resonance and involve sequential injections of analyte over a desired concentration range on a single ligand coated sensor chip without waiting for complete dissociation between the injections. We show that applying this method to biolayer interferometry is straightforward and i) circumvents problems in data evaluation caused by unavoidable sensor differences, ii) saves resources and iii) increases throughput if screening a multitude of different analyte/ligand combinations. PMID:25229647

  12. Thermodynamics, kinetics and process control of nitriding

    DEFF Research Database (Denmark)

    Mittemeijer, Eric J.; Somers, Marcel A. J.

    1997-01-01

    As a prerequisite for the predictability of properties obtained by a nitriding treatment of iron based workpieces, the relation between the process parameters and the composition and structure of the surface layer produced must be known. At present, even the description of thermodynamic equilibrium...... of the International Federation for Heat Treatment and Surface Engineering held in Brighton, UK on 1-5 September 1996. (C) 1997 The Institute of Materials......., the nitriding result is determined largely by kinetics. Nitriding kinetics are shown to be characterised by local near equilibria and stationary states at surfaces and interfaces, and the diffusion coefficient of nitrogen in the various phases, for which new data are presented. The necessary background...

  13. Kinetics of the chiral phase transition

    Energy Technology Data Exchange (ETDEWEB)

    Hees, Hendrik van [Johann-Wolfgang-Goethe-Universitaet Frankfurt, Institut fuer Theoretische Physik, Frankfurt (Germany); Frankfurt Institute for Advanced Studies (FIAS), Frankfurt (Germany); Wesp, Christian; Meistrenko, Alex; Greiner, Carsten [Johann-Wolfgang-Goethe-Universitaet Frankfurt, Institut fuer Theoretische Physik, Frankfurt (Germany)

    2016-07-01

    We simulate the kinetics of the chiral phase transition in hot and dense strongly interacting matter within a novel kinetic-theory approach. Employing an effective linear σ model for quarks, σ mesons, and pions we treat the quarks within a test-particle ansatz for solving the Boltzmann transport equation and the mesons in terms of classical fields. The decay-recombination processes like σ <-> anti q+q are treated using a kind of wave-particle dualism using the exact conservation of energy and momentum. After demonstrating the correct thermodynamic limit for particles and fields in a ''box calculation'' we apply the simulation to the dynamics of an expanding fireball similar to the medium created in ultrarelativistic heavy-ion collisions.

  14. Reaction kinetics of bond rotations in graphene

    KAUST Repository

    Skowron, Stephen T.

    2016-04-12

    The formation and healing processes of the fundamental topological defect in graphitic materials, the Stone-Wales (SW) defect, are brought into a chemical context by considering the rotation of a carbon-carbon bond as chemical reaction. We investigate the rates and mechanisms of these SW transformations in graphene at the atomic scale using transmission electron microscopy. We develop a statistical atomic kinetics formalism, using direct observations obtained under different conditions to determine key kinetic parameters of the reactions. Based on the obtained statistics we quantify thermally and irradiation induced routes, identifying a thermal process of healing with an activation energy consistent with predicted adatom catalysed mechanisms. We discover exceptionally high rates for irradiation induced SW healing, incompatible with the previously assumed mechanism of direct knock-on damage and indicating the presence of an efficient nonadiabatic coupling healing mechanism involving beam induced electronic excitations of the SW defect.

  15. Thermodynamics, Kinetics and Microstructural Evolution during Nitrocarburising

    DEFF Research Database (Denmark)

    Somers, Marcel A.J.; Du, Hong

    2000-01-01

    The evolution of the phase distribution, the composition and the growth kinetics of the compound layer is described for nitrocarburising experiments at well defined combinations of nitriding and carburising potentials in the gaseous environment. Initially, the compound layer development is associ......The evolution of the phase distribution, the composition and the growth kinetics of the compound layer is described for nitrocarburising experiments at well defined combinations of nitriding and carburising potentials in the gaseous environment. Initially, the compound layer development...... for compound layers where epsilon carbonitride phase is the dominant phase and extends from the surface to the interface with the substrate. Both cementite and gamma' phase, with narrow composition ranges, reduce the growth rate. Modelling of the microstructure evolution during nitrocarburising is hindered...

  16. An Inversion Recovery NMR Kinetics Experiment

    OpenAIRE

    Williams, Travis J.; Kershaw, Allan D.; Li, Vincent; Wu, Xinping

    2011-01-01

    A convenient laboratory experiment is described in which NMR magnetization transfer by inversion recovery is used to measure the kinetics and thermochemistry of amide bond rotation. The experiment utilizes Varian spectrometers with the VNMRJ 2.3 software, but can be easily adapted to any NMR platform. The procedures and sample data sets in this article will enable instructors to use inversion recovery as a laboratory activity in applied NMR classes and provide research students with a conveni...

  17. Kinetics of catalytic reactions solutions manual

    CERN Document Server

    Vannice, M Albert

    2005-01-01

    Including countless exercises and worked examples, this advanced reference work and textbook will be extremely useful for the work of many industrial scientists. It teaches readers to design kinetic experiments involving heterogeneous catalysts, to characterize these catalysts, to acquire rate data, to find heat and mass transfer limitations in these data, to select reaction models, to derive rate expressions based on these models, and to assess the consistency of these rate equations.

  18. Kinetic reduction of mill scale via hydrogen

    Directory of Open Access Journals (Sweden)

    Gaballah N.M.

    2014-01-01

    Full Text Available Mill scale is very attractive industrial waste since it is rich in iron (about = 72 % Fe and it is suiTab. for direct recycling to the blast furnace via sintering plant. In this paper the characterizations of raw materials were studied by different methods of analyses. The produced briquettes were reduced with different amounts of hydrogen at varying temperatures, and the reduction kinetics was determined. Two models were applied and the energy of activation was calculated.

  19. Nanostructured energy devices equilibrium concepts and kinetics

    CERN Document Server

    Bisquert, Juan

    2014-01-01

    Due to the pressing needs of society, low cost materials for energy devices have experienced an outstanding development in recent times. In this highly multidisciplinary area, chemistry, material science, physics, and electrochemistry meet to develop new materials and devices that perform required energy conversion and storage processes with high efficiency, adequate capabilities for required applications, and low production cost. Nanostructured Energy Devices: Equilibrium Concepts and Kinetics introduces the main physicochemical principles that govern the operation of energy devices. It inclu

  20. Kinetics of enzymatic hydrolysis of methyl ricinoleate

    OpenAIRE

    Neeharika, T. S.V.R.; Lokesh, P.; Prasanna Rani, K. N.; Prathap Kumar, T.; Prasad, R. B.N.

    2015-01-01

    Ricinoleic acid is an unsaturated hydroxy fatty acid that naturally occurs in castor oil in proportions of up to 85–90%. Ricinoleic acid is a potential raw material and finds several applications in coatings, lubricant formulations and pharmaceutical areas. Enzymatic hydrolysis of castor oil is preferred over conventional hydrolysis for the preparation of ricinoleic acid to avoid estolide formation. A kinetics analysis of the enzymatic hydrolysis of Methyl Ricinoleate in the presence of Candi...

  1. The kinetic characteristics in competitive slalom skiing

    OpenAIRE

    Lappi, Marjaana

    2009-01-01

    Masteroppgave – Norges idrettshøgskole, 2009. The purpose of the present study was to quantify and describe ground reaction forces in competitive slalom skiing. Background: Recent alpine skiing research has measured forces in skiing using instrumentation which interferes to some extent with skiing technique. Instead, the rationale of this study was to estimate kinetic characteristics in competitive slalom skiing using plantar pressure measurement which minimizes technical inter...

  2. The Balescu kinetic equation with exchange interaction

    International Nuclear Information System (INIS)

    Belyi, V V; Kukharenko, Yu A

    2009-01-01

    Starting with the quantum BBGKY hierarchy for the distribution functions, we have obtained the quantum kinetic equation including the dynamical screening of the interaction potential, which exactly takes into account the exchange scattering in the plasma. The collision integral is expressed in terms of the Green function of the linearized Hartree–Fock equation. The potential energy takes into account the polarization and exchange interaction too

  3. Epinephrine kinetics in humans: Radiotracer methodology

    International Nuclear Information System (INIS)

    Rosen, S.G.; Linares, O.A.; Sanfield, J.A.; Zech, L.A.; Lizzio, V.P.; Halter, J.B.

    1989-01-01

    The use of the plasma epinephrine (EPI) level as an index of adrenomedullary activity in humans is complicated by the rapid removal of EPI from plasma by many tissues. To determine whether the kinetics of distribution and metabolism of EPI could be best quantified using the isotope dilution method or a mathematical modeling technique, eight human subjects received a [ 3 H]EPI infusion for 50-60 min. Analysis of the steady state arterialized plasma levels of EPI and [ 3 H]EPI using the isotope dilution technique showed that the basal plasma EPI appearance rate is 0.87 ± 0.11 nmol/m2.min, and the basal plasma EPI clearance rate is 1.63 ± 0.14 L/min.m2. Mathematical modeling of the [ 3 H]EPI levels revealed that a biexponential curve fit was superior to monoexponential and triexponential curve fits. A two-compartment model was the minimal compartment model that accurately described EPI kinetics. The basal plasma EPI appearance (0.82 ± 0.16 nmol/m2.min) and EPI clearance (1.67 ± 0.15 L/min.m2) rates that were estimated from this two-compartment model are similar to the results derived from the isotope dilution method. Mathematical modeling revealed a large extravascular mass of EPI. We conclude that the isotope dilution and mathematical modeling techniques similarly describe plasma EPI kinetics in humans. Kinetic analysis using mathematical modeling provides new insights into adrenomedullary function in humans

  4. Kinetics model development of cocoa bean fermentation

    Science.gov (United States)

    Kresnowati, M. T. A. P.; Gunawan, Agus Yodi; Muliyadini, Winny

    2015-12-01

    Although Indonesia is one of the biggest cocoa beans producers in the world, Indonesian cocoa beans are oftenly of low quality and thereby frequently priced low in the world market. In order to improve the quality, adequate post-harvest cocoa processing techniques are required. Fermentation is the vital stage in series of cocoa beans post harvest processing which could improve the quality of cocoa beans, in particular taste, aroma, and colours. During the fermentation process, combination of microbes grow producing metabolites that serve as the precursors for cocoa beans flavour. Microbial composition and thereby their activities will affect the fermentation performance and influence the properties of cocoa beans. The correlation could be reviewed using a kinetic model that includes unstructured microbial growth, substrate utilization and metabolic product formation. The developed kinetic model could be further used to design cocoa bean fermentation process to meet the expected quality. Further the development of kinetic model of cocoa bean fermentation also serve as a good case study of mixed culture solid state fermentation, that has rarely been studied. This paper presents the development of a kinetic model for solid-state cocoa beans fermentation using an empirical approach. Series of lab scale cocoa bean fermentations, either natural fermentations without starter addition or fermentations with mixed yeast and lactic acid bacteria starter addition, were used for model parameters estimation. The results showed that cocoa beans fermentation can be modelled mathematically and the best model included substrate utilization, microbial growth, metabolites production and its transport. Although the developed model still can not explain the dynamics in microbial population, this model can sufficiently explained the observed changes in sugar concentration as well as metabolic products in the cocoa bean pulp.

  5. Uncertainty quantification for hyperbolic and kinetic equations

    CERN Document Server

    Pareschi, Lorenzo

    2017-01-01

    This book explores recent advances in uncertainty quantification for hyperbolic, kinetic, and related problems. The contributions address a range of different aspects, including: polynomial chaos expansions, perturbation methods, multi-level Monte Carlo methods, importance sampling, and moment methods. The interest in these topics is rapidly growing, as their applications have now expanded to many areas in engineering, physics, biology and the social sciences. Accordingly, the book provides the scientific community with a topical overview of the latest research efforts.

  6. A stochastic model of enzyme kinetics

    Science.gov (United States)

    Stefanini, Marianne; Newman, Timothy; McKane, Alan

    2003-10-01

    Enzyme kinetics is generally modeled by deterministic rate equations, and in the simplest case leads to the well-known Michaelis-Menten equation. It is plausible that stochastic effects will play an important role at low enzyme concentrations. We have addressed this by constructing a simple stochastic model which can be exactly solved in the steady-state. Throughout a wide range of parameter values Michaelis-Menten dynamics is replaced by a new and simple theoretical result.

  7. Gas transport in tight porous media Gas kinetic approach

    DEFF Research Database (Denmark)

    Shapiro, Alexander; Wesselingh, Johannes

    2008-01-01

    We describe the flow of gas in a porous medium in the kinetic regime, where the viscous flow structure is not formed in separate pores. Special attention is paid to the dense kinetic regime, where the interactions within the gas are as important as the interaction with the porous medium....... The transport law for this regime is derived by means of the gas kinetic theory, in the framework of the model of "heavy gas in light one". The computations of the gas kinetic theory are confirmed by the dimension analysis and a simplified derivation revealing the considerations behind the kinetic derivation...

  8. A Century of Enzyme Kinetic Analysis, 1913 to 2013

    Science.gov (United States)

    Johnson, Kenneth A.

    2013-01-01

    This review traces the history and logical progression of methods for quantitative analysis of enzyme kinetics from the 1913 Michaelis and Menten paper to the application of modern computational methods today. Following a brief review of methods for fitting steady state kinetic data, modern methods are highlighted for fitting full progress curve kinetics based upon numerical integration of rate equations, including a re-analysis of the original Michaelis-Menten full time course kinetic data. Finally, several illustrations of modern transient state kinetic methods of analysis are shown which enable the elucidation of reactions occurring at the active sites of enzymes in order to relate structure and function. PMID:23850893

  9. Fast kinetics of calcium dissociation from calsequestrin

    Directory of Open Access Journals (Sweden)

    MARIANELA BELTRÁN

    2006-01-01

    Full Text Available We measured the kinetics of calcium dissociation from calsequestrin in solution or forming part of isolated junctional sarcoplasmic reticulum membranes by mixing calsequestrin equilibrated with calcium with calcium-free solutions in a stopped-flow system. In parallel, we measured the kinetics of the intrinsic fluorescence changes that take place following calcium dissociation from calsequestrin. We found that at 25ºC calcium dissociation was 10-fold faster for calsequestrin attached to junctional membranes (k = 109 s-1 than in solution. These results imply that calcium dissociation from calsequestrin in vivo is not rate limiting during excitation-contraction coupling. In addition, we found that the intrinsic fluorescence decrease for calsequestrin in solution or forming part of junctional membranes was significantly slower than the rates of calcium dissociation. The kinetics of intrinsic fluorescence changes had two components for calsequestrin associated to junctional membranes and only one for calsequestrin in solution; the faster component was 8-fold faster (k = 54.1 s-1 than the slower component (k = 6.9 s-1, which had the same k value as for calsequestrin in solution. These combined results suggest that the presence of calsequestrin at high concentrations in a restricted space, such as when bound to the junctional membrane, accelerates calcium dissociation and the resulting structural changes, presumably as a result of cooperative molecular interactions.

  10. Kinetics of jump landing in agility dogs.

    Science.gov (United States)

    Pfau, Thilo; Garland de Rivaz, Alison; Brighton, Stephanie; Weller, Renate

    2011-11-01

    A recent survey reported an increased risk of injury in dogs participating in agility, a competitive canine sport involving different jumping activities. The aim of this study was to quantify the kinetic parameters during jump landing for commonly used obstacle types. It was hypothesised that with increasing obstacle height, the vertical force and vertical and accelerative horizontal impulse will increase as a result of a lengthened aerial phase, a more acute landing angle and the need to convert potential into forwards kinetic energy. Simultaneous kinetic and kinematic data were recorded from 11 competition agility dogs jumping over obstacle combinations of different height and inter-obstacle distance. Speed and landing angle of the second of the two consecutive jumps were successfully controlled by obstacle height and distance between obstacles. Statistical analysis showed differences between obstacles for peak vertical force, vertical impulse and accelerative horizontal impulse (increasing values with more acute landing angles). Extremely high peak vertical force was observed in the forelimbs (4.5 times bodyweight) when landing from a hurdle jump at high speed. Further detailed studies into the consequences for internal limb structures are warranted in order to clarify how this might be related to injury. Copyright © 2010 Elsevier Ltd. All rights reserved.

  11. Drying kinetics of some building materials

    Directory of Open Access Journals (Sweden)

    A. Moropoulou

    2005-06-01

    Full Text Available Moisture is one of the most deteriorating factors of buildings. The deteriorating effect of moisture occurs mainly during the drying phase, and not in the wetting phase. Appropriate parameters of the drying kinetics are required for the building materials. Environmental factors, such as air temperature, air humidity, and air velocity affect drying. An experimental air dryer of controlled drying air conditions was used to investigate the drying performance of 4 stone materials, 2 bricks and 7 plasters. Drying kinetics was examined at 4 air temperatures, 6 air humidities, and 3 air velocities. A first-order kinetics model was obtained, in which the drying time constant was a function of the drying conditions, and the equilibrium material moisture content was described by the Oswin equation. The parameters of the proposed model were found to be affected strongly by the material and the drying air conditions. The results obtained are very useful in selecting the appropriate plaster to protect existing historic buildings.

  12. Kinetics of weakly turbulent wave fields

    International Nuclear Information System (INIS)

    Erofeev, V.I.; Malkin, V.M.

    1988-01-01

    Only the first nonvanishing term in the expansion of collision integral in powers of wave enrgy is usually considered. Nevertheless the highr collisional terms in the wave kinetic equation can be dominant in the energy range, where the turbulence still remains weak. These terms can be essential even when they are smaller than the first one, if they violate some of the conservation laws correct in the first approximation. The previous attempts to calculate higher nonlinear terms in the wave kinetic equation resulyed in divergencies. Up to now there was no effctive way to aliminate such divergencies. This problem is solved in the present paper with the help of the Wyld's diagram technique. As a result the structure of collision intgral is clear up in everfy order of its power expansion in wave energy and conditions of a kinetic equation applicability are specified. Th cubic collisional term for waves with the decay dispersion law is calculated correctly as an example of application of this method. 15 refs

  13. Optimization of KINETICS Chemical Computation Code

    Science.gov (United States)

    Donastorg, Cristina

    2012-01-01

    NASA JPL has been creating a code in FORTRAN called KINETICS to model the chemistry of planetary atmospheres. Recently there has been an effort to introduce Message Passing Interface (MPI) into the code so as to cut down the run time of the program. There has been some implementation of MPI into KINETICS; however, the code could still be more efficient than it currently is. One way to increase efficiency is to send only certain variables to all the processes when an MPI subroutine is called and to gather only certain variables when the subroutine is finished. Therefore, all the variables that are used in three of the main subroutines needed to be investigated. Because of the sheer amount of code that there is to comb through this task was given as a ten-week project. I have been able to create flowcharts outlining the subroutines, common blocks, and functions used within the three main subroutines. From these flowcharts I created tables outlining the variables used in each block and important information about each. All this information will be used to determine how to run MPI in KINETICS in the most efficient way possible.

  14. Kinetic mechanism of DNA polymerase I (Klenow)

    International Nuclear Information System (INIS)

    Kuchta, R.D.; Mizrahi, V.; Benkovic, P.A.; Johnson, K.A.; Benkovic, S.J.

    1987-01-01

    The minimal kinetic scheme for DNA polymerization catalyzed by the Klenow fragment of DNA polymerase I (KF) from Escherichia coli has been determined with short DNA oligomers of defined sequence, labeled with [ 32 P]-nucleotides. A key feature of this scheme is a minimal two-step sequence that interconverts the ternary KF-DNA/sub n/-dNTP and KF-DNA/sub n+1/-PP/sub i/ complexes. The rate is not limited by the actual polymerization but by a separate step, possibly important in ensuring fidelity. Evidence for this sequence is supplied by the observation of biphasic kinetics in single-turnover pyrophosphorolysis experiments (the microscopic reverse of polymerization). Data analysis then provides an estimate of the internal equilibrium constant. The dissociations of DNA, dNTP, and PP/sub i/ from the various binary and ternary complexes were measured by partitioning (isotope-trapping) experiments. The rate constant for DNA dissociation from KF is sequence dependent and is rate limiting during nonprocessive DNA synthesis. The combination of single-turnover (both directions) and isotope-trapping experiments provides sufficient information to permit a quantitative evaluation of the kinetic scheme for specific DNA sequences

  15. Kinetics of infrared stimulated luminescence from feldspars

    International Nuclear Information System (INIS)

    Jain, M.; Sohbati, R.; Guralnik, B.; Murray, A.S.; Kook, M.; Lapp, T.; Prasad, A.K.; Thomsen, K.J.; Buylaert, J.P.

    2015-01-01

    We extend the localised transition model based on randomly varying recombination distances (Jain et al., 2012) to include Arrhenius analysis and truncated nearest neighbour distributions. The model makes important predictions regarding a) the physical understanding of the linear intercepts in the Arrhenius analysis for localised recombination systems and b) the relationship between charge depletion and shape of the luminescence decay curves; these predictions are successfully tested by experimental investigations. We demonstrate that this model successfully describes the kinetic behaviour, both thermal and optical, of the infrared stimulated luminescence signal from feldspar. Based on the application of this model, it is concluded that different infra-red stimulated luminescence emissions (UV, blue, yellow and far-red) follow the same kinetics, and, therefore, involve participation of the same electron (dosimetric) trap. The differences in thermal stabilities of the different emissions results from differences in number densities of the recombination sites. The results have implications for understanding the mechanism of the far-red emission, and the spatial distributions of recombination sites in feldspar. - Highlights: • Arrhenius analysis of IRSL based on localized transition model (Jain et al., 2012). • Kinetics of IRSL for the different emission bands. • A new analytical description for IRSL. • Demonstrating that feldspar IRSL is consistent with the predictions of the LTM.

  16. Chemical kinetics and modeling of planetary atmospheres

    Science.gov (United States)

    Yung, Yuk L.

    1990-01-01

    A unified overview is presented for chemical kinetics and chemical modeling in planetary atmospheres. The recent major advances in the understanding of the chemistry of the terrestrial atmosphere make the study of planets more interesting and relevant. A deeper understanding suggests that the important chemical cycles have a universal character that connects the different planets and ultimately link together the origin and evolution of the solar system. The completeness (or incompleteness) of the data base for chemical kinetics in planetary atmospheres will always be judged by comparison with that for the terrestrial atmosphere. In the latter case, the chemistry of H, O, N, and Cl species is well understood. S chemistry is poorly understood. In the atmospheres of Jovian planets and Titan, the C-H chemistry of simple species (containing 2 or less C atoms) is fairly well understood. The chemistry of higher hydrocarbons and the C-N, P-N chemistry is much less understood. In the atmosphere of Venus, the dominant chemistry is that of chlorine and sulfur, and very little is known about C1-S coupled chemistry. A new frontier for chemical kinetics both in the Earth and planetary atmospheres is the study of heterogeneous reactions. The formation of the ozone hole on Earth, the ubiquitous photochemical haze on Venus and in the Jovian planets and Titan all testify to the importance of heterogeneous reactions. It remains a challenge to connect the gas phase chemistry to the production of aerosols.

  17. Predicting DNA hybridization kinetics from sequence

    Science.gov (United States)

    Zhang, Jinny X.; Fang, John Z.; Duan, Wei; Wu, Lucia R.; Zhang, Angela W.; Dalchau, Neil; Yordanov, Boyan; Petersen, Rasmus; Phillips, Andrew; Zhang, David Yu

    2018-01-01

    Hybridization is a key molecular process in biology and biotechnology, but so far there is no predictive model for accurately determining hybridization rate constants based on sequence information. Here, we report a weighted neighbour voting (WNV) prediction algorithm, in which the hybridization rate constant of an unknown sequence is predicted based on similarity reactions with known rate constants. To construct this algorithm we first performed 210 fluorescence kinetics experiments to observe the hybridization kinetics of 100 different DNA target and probe pairs (36 nt sub-sequences of the CYCS and VEGF genes) at temperatures ranging from 28 to 55 °C. Automated feature selection and weighting optimization resulted in a final six-feature WNV model, which can predict hybridization rate constants of new sequences to within a factor of 3 with ∼91% accuracy, based on leave-one-out cross-validation. Accurate prediction of hybridization kinetics allows the design of efficient probe sequences for genomics research.

  18. Kinetics of saccharose fermentation by Kombucha

    Directory of Open Access Journals (Sweden)

    Lončar Eva S.

    2014-01-01

    Full Text Available Kinetics of saccharose fermentation by Kombucha is not yet well defined due to lack of knowledge of reaction mechanisms taking place during this process. In this research kinetics of saccharose fermentation by Kombucha was analysed using the suggested empirical model. The data were obtained on 1.5 g L-1 of black tea, with 66.47 g L-1 of saccharose and using 10% (v/v or 15% (v/v of Kombucha. Total number of viable cells was as follows: approximately 5x105 of yeast cells per mL of the inoculum and approximately 2x106 of bacteria cells per mL of the inoculum. The samples were analysed after 0, 3, 4, 5, 6, 7 and 10 days. Their pH values and contents of saccharose, glucose, fructose, total acids and ethanol were determined. A saccharose concentration model was defined as sigmoidal function at 22oC and 30oC, and with 10% (v/v and 15% (v/v of inoculum quantity. Determination coefficients of the functions were very high (R2>0.99. Reaction rates were calculated as first derivatives of Boltzmann’s functions. No simple correlation between rate of reaction and independent variables (temperature and inoculum concentration was found. Analysis of empirical model indicated that saccharose fermentation by Kombucha occurred according to very complex kinetics. [Projekat Ministarstva nauke Republike Srbije, br. III 46009

  19. Drainage and Stratification Kinetics of Foam Films

    Science.gov (United States)

    Zhang, Yiran; Sharma, Vivek

    2014-03-01

    Baking bread, brewing cappuccino, pouring beer, washing dishes, shaving, shampooing, whipping eggs and blowing bubbles all involve creation of aqueous foam films. Foam lifetime, drainage kinetics and stability are strongly influenced by surfactant type (ionic vs non-ionic), and added proteins, particles or polymers modify typical responses. The rate at which fluid drains out from a foam film, i.e. drainage kinetics, is determined in the last stages primarily by molecular interactions and capillarity. Interestingly, for certain low molecular weight surfactants, colloids and polyelectrolyte-surfactant mixtures, a layered ordering of molecules, micelles or particles inside the foam films leads to a stepwise thinning phenomena called stratification. Though stratification is observed in many confined systems including foam films containing particles or polyelectrolytes, films containing globular proteins seem not to show this behavior. Using a Scheludko-type cell, we experimentally study the drainage and stratification kinetics of horizontal foam films formed by protein-surfactant mixtures, and carefully determine how the presence of proteins influences the hydrodynamics and thermodynamics of foam films.

  20. MODELING STYRENE HYDROGENATION KINETICS USING PALLADIUM CATALYSTS

    Directory of Open Access Journals (Sweden)

    G. T. Justino

    Full Text Available Abstract The high octane number of pyrolysis gasoline (PYGAS explains its insertion in the gasoline pool. However, its use is troublesome due to the presence of gum-forming chemicals which, in turn, can be removed via hydrogenation. The use of Langmuir-Hinshelwood kinetic models was evaluated for hydrogenation of styrene, a typical gum monomer, using Pd/9%Nb2O5-Al2O3 as catalyst. Kinetic models accounting for hydrogen dissociative and non-dissociative adsorption were considered. The availability of one or two kinds of catalytic sites was analyzed. Experiments were carried out in a semi-batch reactor at constant temperature and pressure in the absence of transport limitations. The conditions used in each experiment varied between 16 - 56 bar and 60 - 100 ºC for pressure and temperature, respectively. The kinetic models were evaluated using MATLAB and EMSO software. Models using adsorption of hydrogen and organic molecules on the same type of site fitted the data best.

  1. Neptunium Binding Kinetics with Arsenazo(III)

    Energy Technology Data Exchange (ETDEWEB)

    Martin, Leigh R. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Johnson, Aaron T. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Mezyk, Stephen P. [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2014-08-01

    This document has been prepared to meet FCR&D level 2 milestone M2FT-14IN0304021, “Report on the results of actinide binding kinetics with aqueous phase complexants” This work was carried out under the auspices of the Thermodynamics and Kinetics of Advanced Separations Systems FCR&D work package. The report details kinetics experiments that were performed to measure rates of aqueous phase complexation for pentavalent neptunium with the chromotropic dye Arsenazo III (AAIII). The studies performed were designed to determine how pH, ionic strength and AAIII concentration may affect the rate of the reaction. A brief comparison with hexavalent neptunium is also made. It was identified that as pH was increased the rate of reaction also increased, however increasing the ionic strength and concentration of AAIII had the opposite effect. Interestingly, the rate of reaction of Np(VI) with AAIII was found to be slower than that of the Np(V) reaction.

  2. Detailed chemical kinetic modeling of cyclohexane oxidation.

    Science.gov (United States)

    Silke, Emma J; Pitz, William J; Westbrook, Charles K; Ribaucour, Marc

    2007-05-17

    A detailed chemical kinetic mechanism has been developed and used to study the oxidation of cyclohexane at both low and high temperatures. Rules for reaction rate constants are developed for the low-temperature combustion of cyclohexane. These rules can be used for in chemical kinetic mechanisms for other cycloalkanes. Because cyclohexane produces only one type of cyclohexyl radical, much of the low-temperature chemistry of cyclohexane is described in terms of one potential energy diagram showing the reaction of cyclohexyl radical with O2 through five-, six-, and seven-membered-ring transition states. The direct elimination of cyclohexene and HO2 from RO2 is included in the treatment using a modified rate constant of Cavallotti et al. (Proc. Combust. Inst. 2007, 31, 201). Published and unpublished data from the Lille rapid compression machine, as well as jet-stirred reactor data, are used to validate the mechanism. The effect of heat loss is included in the simulations, an improvement on previous studies on cyclohexane. Calculations indicated that the production of 1,2-epoxycyclohexane observed in the experiments cannot be simulated according to the current understanding of low-temperature chemistry. Possible "alternative" H-atom isomerizations leading to different products from the parent O2QOOH radical were included in the low-temperature chemical kinetic mechanism and were found to play a significant role.

  3. Kinetic theory for interacting Luttinger liquids

    Science.gov (United States)

    Buchhold, Michael; Diehl, Sebastian

    2015-10-01

    We derive a closed set of equations for the kinetics and non-equilibrium dynamics of interacting Luttinger Liquids with cubic resonant interactions. In the presence of these interactions, the Luttinger phonons become dressed but still well defined quasi-particles, characterized by a life-time much larger then the inverse energy. This enables the separation of forward time dynamics and relative time dynamics into slow and fast dynamics and justifies the so-called Wigner approximation, which can be seen as a "local-time approximation" for the relative dynamics. Applying field theoretical methods in the Keldysh framework, i.e. kinetic and Dyson-Schwinger equations, we derive a closed set of dynamic equations, describing the kinetics of normal and anomalous phonon densities, the phonon self-energy and vertex corrections for a Gaussian non-equilibrium initial state. In the limit of low phonon densities, the results from self-consistent Born approximation are recaptured, including Andreev's scaling solution for the quasi-particle life-time in a thermal state. As an application, we compute the relaxation of an excited state to its thermal equilibrium. While the intermediate time dynamics displays exponentially fast relaxation, the last stages of thermalization are governed by algebraic laws. This can be traced back to the importance of energy and momentum conservation at the longest times, which gives rise to dynamical slow modes.

  4. A kinetic model for chemical neurotransmission

    Science.gov (United States)

    Ramirez-Santiago, Guillermo; Martinez-Valencia, Alejandro; Fernandez de Miguel, Francisco

    Recent experimental observations in presynaptic terminals at the neuromuscular junction indicate that there are stereotyped patterns of cooperativeness in the fusion of adjacent vesicles. That is, a vesicle in hemifusion process appears on the side of a fused vesicle and which is followed by another vesicle in a priming state while the next one is in a docking state. In this talk we present a kinetic model for this morphological pattern in which each vesicle state previous to the exocytosis is represented by a kinetic state. This chain states kinetic model can be analyzed by means of a Master equation whose solution is simulated with the stochastic Gillespie algorithm. With this approach we have reproduced the responses to the basal release in the absence of stimulation evoked by the electrical activity and the phenomena of facilitation and depression of neuromuscular synapses. This model offers new perspectives to understand the underlying phenomena in chemical neurotransmission based on molecular interactions that result in the cooperativity between vesicles during neurotransmitter release. DGAPA Grants IN118410 and IN200914 and Conacyt Grant 130031.

  5. Evaluation of kinetic energy in flowing rivers

    Energy Technology Data Exchange (ETDEWEB)

    Faure, T. [National Research Council of Canada, Ottawa, ON (Canada). Canadian Hydraulics Centre

    2008-07-01

    New methods of evaluating the kinetic energy in rivers were discussed. Developed by the National Research Council's Canadian Hydraulics Centre, the numerical models were designed to generate hydrographs of river flow from dams; accommodate power density anomalies caused by the presence of islands in a river; and assess mean kinetic power rates. This presentation provided details of a simulation of 6 turbines located in close proximity to each other. The model was used to calculate velocity fields downstream of the turbines as well as changes in water surface elevation due to power production by the 6 75 kW turbines. Turbine power extraction and kinetic power in the upstream cross-section was assessed. The model showed that the turbines extracted 9 per cent of the river's 17,000 kW of estimated energy potential. The turbines were modelled by considering the porosity of the numerical elements at the location of the turbine and extracting known quantities of energy from the flow. The model was also used to calculate new hydrodynamics of the whole region with the turbines in place by assuming that energy was extracted over the entire depth of the location. The presentation included detailed charts of rivers modelled during the study. tabs., figs.

  6. Electrode Kinetics and Gas Conversion in Solid Oxide Cells

    DEFF Research Database (Denmark)

    Njodzefon, Jean-Claude

    that the kinetics at the fuel electrode were exactly the same in both reformates. This means that chemical equilibrium reactions were much faster than the electrochemical reactions. The electrode displayed slightly faster kinetics in hydrogen/steam fuel than in the reformate fuels. To minimize the influence of (i...... slower reaction kinetics under cathodic mode operation at 50 mV overvoltage than in anodic mode. The trend was opposite for the lower performing La0.58Sr0.4Co0.2Fe0.8O3 (LSCF) oxygen electrode. However, with decreasing oxygen partial pressure both electrodes displayed increasing asymmetry between anodic...... and cathodic modes. It could be shown that surface exchange kinetics were the major cause of the decreasing kinetics with decreasing pO2 and that the cathodic mode kinetics were slowed down much more than the anodic branch kinetics thus increasing the asymmetry. Independent of operation mode, commercialization...

  7. Mechanochemical Kinetics in Elastomeric Polymer Networks: Heterogeneity of Local Forces Results in Nonexponential Kinetics.

    Science.gov (United States)

    Adhikari, Ramesh; Makarov, Dmitrii E

    2017-03-16

    A common approach to inducing selective mechanochemical transformations relies on embedding the target molecules (called mechanophores) within elastomeric polymer networks. Mechanical properties of such elastomers can also be modulated through the mechanochemical response of the constituent polymer chains. The inherent randomness in the molecular structure of such materials leads to heterogeneity of the local forces exerted on individual mechanophores. Here we use coarse-grained simulations to study the force distributions within random elastomeric networks and show that those distributions are close to exponential regardless of the applied macroscopic load, entanglement effects, or network parameters. Exponential form of the distribution allows one to completely characterize the mechanophore kinetics in terms of the mean value of the force. At the same time, heterogeneity of the local force affects the kinetics qualitatively: While a narrow force distribution around the mean would lead to exponential kinetics, exponential force distribution results in highly nonexponential kinetics, with a fast kinetic phase involving highly loaded molecules, followed by a slow phase dominated by unloaded molecules.

  8. Kinetics and hybrid kinetic-fluid models for nonequilibrium gas and plasmas

    International Nuclear Information System (INIS)

    Crouseilles, N.

    2004-12-01

    For a few decades, the application of the physics of plasmas has appeared in different fields like laser-matter interaction, astrophysics or thermonuclear fusion. In this thesis, we are interested in the modeling and the numerical study of nonequilibrium gas and plasmas. To describe such systems, two ways are usually used: the fluid description and the kinetic description. When we study a nonequilibrium system, fluid models are not sufficient and a kinetic description have to be used. However, solving a kinetic model requires the discretization of a large number of variables, which is quite expensive from a numerical point of view. The aim of this work is to propose a hybrid kinetic-fluid model thanks to a domain decomposition method in the velocity space. The derivation of the hybrid model is done in two different contexts: the rarefied gas context and the more complicated plasmas context. The derivation partly relies on Levermore's entropy minimization approach. The so-obtained model is then discretized and validated on various numerical test cases. In a second stage, a numerical study of a fully kinetic model is presented. A collisional plasma constituted of electrons and ions is considered through the Vlasov-Poisson-Fokker-Planck-Landau equation. Then, a numerical scheme which preserves total mass and total energy is presented. This discretization permits in particular a numerical study of the Landau damping. (author)

  9. A Simple "Boxed Molecular Kinetics" Approach To Accelerate Rare Events in the Stochastic Kinetic Master Equation.

    Science.gov (United States)

    Shannon, Robin; Glowacki, David R

    2018-02-15

    The chemical master equation is a powerful theoretical tool for analyzing the kinetics of complex multiwell potential energy surfaces in a wide range of different domains of chemical kinetics spanning combustion, atmospheric chemistry, gas-surface chemistry, solution phase chemistry, and biochemistry. There are two well-established methodologies for solving the chemical master equation: a stochastic "kinetic Monte Carlo" approach and a matrix-based approach. In principle, the results yielded by both approaches are identical; the decision of which approach is better suited to a particular study depends on the details of the specific system under investigation. In this Article, we present a rigorous method for accelerating stochastic approaches by several orders of magnitude, along with a method for unbiasing the accelerated results to recover the "true" value. The approach we take in this paper is inspired by the so-called "boxed molecular dynamics" (BXD) method, which has previously only been applied to accelerate rare events in molecular dynamics simulations. Here we extend BXD to design a simple algorithmic strategy for accelerating rare events in stochastic kinetic simulations. Tests on a number of systems show that the results obtained using the BXD rare event strategy are in good agreement with unbiased results. To carry out these tests, we have implemented a kinetic Monte Carlo approach in MESMER, which is a cross-platform, open-source, and freely available master equation solver.

  10. Kinetics of enzyme action on surface-attached substrates: a practical guide to progress curve analysis in any kinetic situation.

    Science.gov (United States)

    Anne, Agnès; Demaille, Christophe

    2012-10-16

    In the present work, exact kinetic equations describing the action of an enzyme in solution on a substrate attached to a surface have been derived in the framework of the Michaelis-Menten mechanism but without resorting to the often-used steady-state approximation. The here-derived kinetic equations are cast in a workable format, allowing us to introduce a simple and universal procedure for the quantitative analysis of enzyme surface kinetics that is valid for any kinetic situation. The results presented here should allow experimentalists studying the kinetics of enzyme action on immobilized substrates to analyze their data in a perfectly rigorous way.

  11. Vlasov simulations of kinetic Alfvén waves at proton kinetic scales

    Energy Technology Data Exchange (ETDEWEB)

    Vásconez, C. L. [Dipartimento di Fisica, Università della Calabria, I-87036 Cosenza (Italy); Observatorio Astronómico de Quito, Escuela Politécnica Nacional, Quito (Ecuador); Valentini, F.; Veltri, P. [Dipartimento di Fisica, Università della Calabria, I-87036 Cosenza (Italy); Camporeale, E. [Centrum Wiskunde and Informatica, Amsterdam (Netherlands)

    2014-11-15

    Kinetic Alfvén waves represent an important subject in space plasma physics, since they are thought to play a crucial role in the development of the turbulent energy cascade in the solar wind plasma at short wavelengths (of the order of the proton gyro radius ρ{sub p} and/or inertial length d{sub p} and beyond). A full understanding of the physical mechanisms which govern the kinetic plasma dynamics at these scales can provide important clues on the problem of the turbulent dissipation and heating in collisionless systems. In this paper, hybrid Vlasov-Maxwell simulations are employed to analyze in detail the features of the kinetic Alfvén waves at proton kinetic scales, in typical conditions of the solar wind environment (proton plasma beta β{sub p} = 1). In particular, linear and nonlinear regimes of propagation of these fluctuations have been investigated in a single-wave situation, focusing on the physical processes of collisionless Landau damping and wave-particle resonant interaction. Interestingly, since for wavelengths close to d{sub p} and β{sub p} ≃ 1 (for which ρ{sub p} ≃ d{sub p}) the kinetic Alfvén waves have small phase speed compared to the proton thermal velocity, wave-particle interaction processes produce significant deformations in the core of the particle velocity distribution, appearing as phase space vortices and resulting in flat-top velocity profiles. Moreover, as the Eulerian hybrid Vlasov-Maxwell algorithm allows for a clean almost noise-free description of the velocity space, three-dimensional plots of the proton velocity distribution help to emphasize how the plasma departs from the Maxwellian configuration of thermodynamic equilibrium due to nonlinear kinetic effects.

  12. Energy Conservation Tests of a Coupled Kinetic-kinetic Plasma-neutral Transport Code

    Energy Technology Data Exchange (ETDEWEB)

    Stotler, D. P.; Chang, C. S.; Ku, S. H.; Lang, J.; Park, G.

    2012-08-29

    A Monte Carlo neutral transport routine, based on DEGAS2, has been coupled to the guiding center ion-electron-neutral neoclassical PIC code XGC0 to provide a realistic treatment of neutral atoms and molecules in the tokamak edge plasma. The DEGAS2 routine allows detailed atomic physics and plasma-material interaction processes to be incorporated into these simulations. The spatial pro le of the neutral particle source used in the DEGAS2 routine is determined from the uxes of XGC0 ions to the material surfaces. The kinetic-kinetic plasma-neutral transport capability is demonstrated with example pedestal fueling simulations.

  13. Droplet Growth Kinetics in Various Environments

    Science.gov (United States)

    Raatikainen, T. E.; Lathem, T. L.; Moore, R.; Lin, J. J.; Cerully, K. M.; Padro, L.; Lance, S.; Cozic, J.; Anderson, B. E.; Nenes, A.

    2012-12-01

    The largest uncertainties in the effects of atmospherics aerosols on the global radiation budget are related to their indirect effects on cloud properties (IPCC, the Fourth Assessment Report of the Intergovernmental Panel on Climate Change, 2007). Cloud formation is a kinetic process where the resulting cloud properties depend on aerosol properties and meteorological parameters such as updraft velocity (e.g. McFiggans et al., Atmos. Chem. Phys., 6, 2593-2649, 2006). Droplet growth rates are limited by the water vapor diffusion, but additional kinetic limitations, e.g., due to organic surface films, slow solute dissociation or highly viscous or glassy aerosol states have been hypothesized. Significant additional kinetic limitations can lead to increased cloud droplet number concentration, thus the effect is similar to those of increased aerosol number concentration or changes in vertical velocity (e.g. Nenes et al., Geophys. Res. Lett., 29, 1848, 2002). There are a few studies where slow droplet growth has been observed (e.g. Ruehl et al., Geophys. Res. Lett., 36, L15814, 2009), however, little is currently known about their global occurrence and magnitude. Cloud micro-physics models often describe kinetic limitations by an effective water vapor uptake coefficient or similar parameter. Typically, determining aerosol water vapor uptake coefficients requires experimental observations of droplet growth which are interpreted by a numerical droplet growth model where the uptake coefficient is an adjustable parameter (e.g. Kolb et al., Atmos. Chem. Phys., 10, 10561-10605, 2010). Such methods have not been practical for high time-resolution or long term field measurements, until a model was recently developed for analyzing Droplet Measurement Technologies (DMT) cloud condensation nuclei (CCN) counter data (Raatikainen et al., Atmos. Chem. Phys., 12, 4227-4243, 2012). Model verification experiments showed that the calibration aerosol droplet size can be predicted accurately

  14. Biodegradation kinetics for pesticide exposure assessment.

    Science.gov (United States)

    Wolt, J D; Nelson, H P; Cleveland, C B; van Wesenbeeck, I J

    2001-01-01

    Understanding pesticide risks requires characterizing pesticide exposure within the environment in a manner that can be broadly generalized across widely varied conditions of use. The coupled processes of sorption and soil degradation are especially important for understanding the potential environmental exposure of pesticides. The data obtained from degradation studies are inherently variable and, when limited in extent, lend uncertainty to exposure characterization and risk assessment. Pesticide decline in soils reflects dynamically coupled processes of sorption and degradation that add complexity to the treatment of soil biodegradation data from a kinetic perspective. Additional complexity arises from study design limitations that may not fully account for the decline in microbial activity of test systems, or that may be inadequate for considerations of all potential dissipation routes for a given pesticide. Accordingly, kinetic treatment of data must accommodate a variety of differing approaches starting with very simple assumptions as to reaction dynamics and extending to more involved treatments if warranted by the available experimental data. Selection of the appropriate kinetic model to describe pesticide degradation should rely on statistical evaluation of the data fit to ensure that the models used are not overparameterized. Recognizing the effects of experimental conditions and methods for kinetic treatment of degradation data is critical for making appropriate comparisons among pesticide biodegradation data sets. Assessment of variability in soil half-life among soils is uncertain because for many pesticides the data on soil degradation rate are limited to one or two soils. Reasonable upper-bound estimates of soil half-life are necessary in risk assessment so that estimated environmental concentrations can be developed from exposure models. Thus, an understanding of the variable and uncertain distribution of soil half-lives in the environment is

  15. Group-kinetic theory of turbulence

    Science.gov (United States)

    Tchen, C. M.

    1986-01-01

    The two phases are governed by two coupled systems of Navier-Stokes equations. The couplings are nonlinear. These equations describe the microdynamical state of turbulence, and are transformed into a master equation. By scaling, a kinetic hierarchy is generated in the form of groups, representing the spectral evolution, the diffusivity and the relaxation. The loss of memory in formulating the relaxation yields the closure. The network of sub-distributions that participates in the relaxation is simulated by a self-consistent porous medium, so that the average effect on the diffusivity is to make it approach equilibrium. The kinetic equation of turbulence is derived. The method of moments reverts it to the continuum. The equation of spectral evolution is obtained and the transport properties are calculated. In inertia turbulence, the Kolmogoroff law for weak coupling and the spectrum for the strong coupling are found. As the fluid analog, the nonlinear Schrodinger equation has a driving force in the form of emission of solitons by velocity fluctuations, and is used to describe the microdynamical state of turbulence. In order for the emission together with the modulation to participate in the transport processes, the non-homogeneous Schrodinger equation is transformed into a homogeneous master equation. By group-scaling, the master equation is decomposed into a system of transport equations, replacing the Bogoliubov system of equations of many-particle distributions. It is in the relaxation that the memory is lost when the ensemble of higher-order distributions is simulated by an effective porous medium. The closure is thus found. The kinetic equation is derived and transformed into the equation of spectral flow.

  16. Kinetics of niobium carbide precipitation in ferrite

    International Nuclear Information System (INIS)

    Gendt, D.

    2001-01-01

    The aim of this study is to develop a NbC precipitation modelling in ferrite. This theoretical study is motivated by the fact it considers a ternary system and focus on the concurrence of two different diffusion mechanisms. An experimental study with TEP, SANS and Vickers micro-hardening measurements allows a description of the NbC precipitation kinetics. The mean radius of the precipitates is characterized by TEM observations. To focus on the nucleation stage, we use the Tomographic Atom Probe that analyses, at an atomistic scale, the position of the solute atoms in the matrix. A first model based on the classical nucleation theory and the diffusion-limited growth describes the precipitation of spherical precipitates. To solve the set of equations, we use a numerical algorithm that furnishes an evaluation of the precipitated fraction, the mean radius and the whole size distribution of the particles. The parameters that are the interface energy, the solubility product and the diffusion coefficients are fitted with the data available in the literature and our experimental results. It allows a satisfactory agreement as regards to the simplicity of the model. Monte Carlo simulations are used to describe the evolution of a ternary alloy Fe-Nb-C on a cubic centred rigid lattice with vacancy and interstitial mechanisms. This is realized with an atomistic description of the atoms jumps and their related frequencies. The model parameters are fitted with phase diagrams and diffusion coefficients. For the sake of simplicity, we consider that the precipitation of NbC is totally coherent and we neglect any elastic strain effect. We can observe different kinetic paths: for low supersaturations, we find an expected precipitation of NbC but for higher supersaturations, the very fast diffusivity of carbon atoms conducts to the nucleation of iron carbide particles. We establish that the occurrence of this second phenomenon depends on the vacancy arrival kinetics and can be related

  17. High-temperature spreading kinetics of metals

    Energy Technology Data Exchange (ETDEWEB)

    Rauch, N.

    2005-05-15

    In this PhD work a drop transfer setup combined with high speed photography has been used to analyze the spreading of Ag on polished polycrystalline Mo and single crystalline Mo (110) and (100) substrates. The objective of this work was to unveil the basic phenomena controlling spreading in metal-metal systems. The observed spreading kinetics were compared with current theories of low and high temperature spreading such as a molecular kinetic model and a fluid flow model. Analyses of the data reveal that the molecular model does describe the fastest velocity data well for all the investigated systems. Therefore, the energy which is dissipated during the spreading process is a dissipation at the triple line rather than dissipation due to the viscosity in the liquid. A comparison of the determined free activation energy for wetting of {delta}G95{approx}145kJ/mol with literature values allows the statement that the rate determining step seems to be a surface diffusion of the Ag atoms along the triple line. In order to investigate possible ridge formation, due to local atomic diffusion of atoms of the substrate at the triple during the spreading process, grooving experiments of the polycrystalline Mo were performed to calculate the surface diffusities that will control ridge evolution. The analyses of this work showed that a ridge formation at the fastest reported wetting velocities was not possible if there is no initial perturbation for a ridge. If there was an initial perturbation for a ridge the ridge had to be much smaller than 1 nm in order to be able to move with the liquid font. Therefore ridge formation does not influence the spreading kinetics for the studied system and the chosen conditions. SEM, AFM and TEM investigations of the triple line showed that ridge formation does also not occur at the end of the wetting experiment when the drop is close to equilibrium and the wetting velocity is slow. (orig.)

  18. Kinetic Analysis of Horizontal Plyometric Exercise Intensity.

    Science.gov (United States)

    Kossow, Andrew J; Ebben, William P

    2018-05-01

    Kossow, AJ, DeChiara, TG, Neahous, SM, and Ebben, WP. Kinetic analysis of horizontal plyometric exercise intensity. J Strength Cond Res 32(5): 1222-1229, 2018-Plyometric exercises are frequently performed as part of a strength and conditioning program. Most studies assessed the kinetics of plyometric exercises primarily performed in the vertical plane. The purpose of this study was to evaluate the multiplanar kinetic characteristics of a variety of plyometric exercises, which have a significant horizontal component. This study also sought to assess sex differences in the intensity progression of these exercises. Ten men and 10 women served as subjects. The subjects performed a variety of plyometric exercises including the double-leg hop, standing long jump, single-leg standing long jump, bounding, skipping, power skipping, cone hops, and 45.72-cm hurdle hops. Subjects also performed the countermovement jump for comparison. All plyometric exercises were evaluated using a force platform. Dependent variables included the landing rate of force development and landing ground reaction forces for each exercise in the vertical, frontal, and sagittal planes. A 2-way mixed analysis of variance with repeated-measures for plyometric exercise type demonstrated main effects for exercise type for all dependent variables (p ≤ 0.001). There was no significant interaction between plyometric exercise type and sex for any of the variable assessed. Bonferroni-adjusted pairwise comparisons identified a number of differences between the plyometric exercises for the dependent variables assessed (p ≤ 0.05). These findings should be used to guide practitioners in the progression of plyometric exercise intensity, and thus program design, for those who require significant horizontal power in their sport.

  19. Kinetic theory for strongly coupled Coulomb systems

    Science.gov (United States)

    Dufty, James; Wrighton, Jeffrey

    2018-01-01

    The calculation of dynamical properties for matter under extreme conditions is a challenging task. The popular Kubo-Greenwood model exploits elements from equilibrium density-functional theory (DFT) that allow a detailed treatment of electron correlations, but its origin is largely phenomenological; traditional kinetic theories have a more secure foundation but are limited to weak ion-electron interactions. The objective here is to show how a combination of the two evolves naturally from the short-time limit for the generator of the effective single-electron dynamics governing time correlation functions without such limitations. This provides a theoretical context for the current DFT-related approach, the Kubo-Greenwood model, while showing the nature of its corrections. The method is to calculate the short-time dynamics in the single-electron subspace for a given configuration of the ions. This differs from the usual kinetic theory approach in which an average over the ions is performed as well. In this way the effective ion-electron interaction includes strong Coulomb coupling and is shown to be determined from DFT. The correlation functions have the form of the random-phase approximation for an inhomogeneous system but with renormalized ion-electron and electron-electron potentials. The dynamic structure function, density response function, and electrical conductivity are calculated as examples. The static local field corrections in the dielectric function are identified in this way. The current analysis is limited to semiclassical electrons (quantum statistical potentials), so important quantum conditions are excluded. However, a quantization of the kinetic theory is identified for broader application while awaiting its detailed derivation.

  20. Kinetic coefficients in isotopically disordered crystals

    International Nuclear Information System (INIS)

    Zhernov, Arkadii P; Inyushkin, Alexander V

    2002-01-01

    Peculiarities of the behavior of kinetic coefficients, like thermal conductivity, electric conductivity, and thermoelectric power, in isotopically disordered materials are reviewed in detail. New experimental and theoretical results on the isotope effects in the thermal conductivity of diamond, Ge, and Si semiconductors are presented. The suppression effect of phonon-drag thermopower in the isotopically disordered Ge crystals is discussed. The influence of dynamic and static crystal lattice deformations on the electric conductivity of metals as well as on the ordinary phonon spectrum deformations is considered. (reviews of topical problems)