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Sample records for clinical quatitative flow

  1. Two-Phase Cavitating Flow in Turbomachines

    Directory of Open Access Journals (Sweden)

    Sandor I. Bernad

    2012-11-01

    Full Text Available Cavitating flows are notoriously complex because they are highly turbulent and unsteady flows involving two species (liquid/vapor with a large density difference. These features pose a unique challenge to numerical modeling works. The study briefly reviews the methodology curently employed for industrial cavitating flow simulations using the two-phase mixture model. The two-phase mixture model is evaluated and validated using benchmark problem where experimental data are available. A 3D cavitating flow computation is performed for the GAMM Francis runner. The model is able to qualitatively predict the location and extent of the 3D cavity on the blade, but further investigation are needed to quatitatively assess the accuracy for real turbomachinery cavitating flows.

  2. Flow Analysis of the Cleveland Clinic Centrifugal Pump

    Science.gov (United States)

    Veres, Joseph P.; Golding, Leonard A. R.; Smith, William A.; Horvath, David; Medvedev, Alexander

    1997-01-01

    An implantable ventricular assist rotordynamic blood pump is being developed by the Cleveland Clinic Foundation in cooperation with the NASA Lewis Research Center. At the nominal design condition, the pump provides blood flow at the rate of 5 liters per minute at a pressure rise of 100 mm of mercury and a rotative speed of 3000 RPM. Bench testing of the centrifugal pump in a water/glycerin mixture has provided flow and pressure data at several rotative speeds. A one-dimensional empirical based pump flow analysis computer code developed at NASA Lewis Research Center has been used in the design process to simulate the flow in the primary centrifugal pump stage. The computer model was used to size key impeller and volute geometric parameters that influence pressure rise and flow. Input requirements to the computer model include a simple representation of the pump geometry. The model estimates the flow conditions at the design and at off-design operating conditions at the impeller leading and trailing edges and the volute inlet and exit. The output from the computer model is compared to flow and pressure data obtained from bench testing.

  3. Improving patient flow at a family health clinic.

    Science.gov (United States)

    Bard, Jonathan F; Shu, Zhichao; Morrice, Douglas J; Wang, Dongyang Ester; Poursani, Ramin; Leykum, Luci

    2016-06-01

    This paper presents an analysis of a residency primary care clinic whose majority of patients are underserved. The clinic is operated by the health system for Bexar County and staffed primarily with physicians in a three-year Family Medicine residency program at The University of Texas School of Medicine in San Antonio. The objective of the study was to obtain a better understanding of patient flow through the clinic and to investigate changes to current scheduling rules and operating procedures. Discrete event simulation was used to establish a baseline and to evaluate a variety of scenarios associated with appointment scheduling and managing early and late arrivals. The first steps in developing the model were to map the administrative and diagnostic processes and to collect time-stamped data and fit probability distributions to each. In conjunction with the initialization and validation steps, various regressions were performed to determine if any relationships existed between individual providers and patient types, length of stay, and the difference between discharge time and appointment time. The latter two statistics along with resource utilization and closing time were the primary metrics used to evaluate system performance.The results showed that up to an 8.5 % reduction in patient length of stay is achievable without noticeably affecting the other metrics by carefully adjusting appointment times. Reducing the no-show rate from its current value of 21.8 % or overbooking, however, is likely to overwhelm the system's resources and lead to excessive congestion and overtime. Another major finding was that the providers are the limiting factor in improving patient flow. With an average utilization rate above 90 % there is little prospect in shortening the total patient time in the clinic without reducing the providers' average assessment time. Finally, several suggestions are offered to ensure fairness when dealing with out-of-order arrivals. PMID:25155098

  4. Coronary Slow Flow Phenomenon Clinical Findings and Predictors

    Science.gov (United States)

    Sanati, Hamidreza; Kiani, Reza; Shakerian, Farshad; Firouzi, Ata; Zahedmehr, Ali; Peighambari, Mohammadmehdi; Shokrian, Leila; Ashrafi, Peiman

    2016-01-01

    Background: In some patients with chest pain, selective coronary angiography reveals slow contrast agent passage through the epicardial coronary arteries in the absence of stenosis. This phenomenon has been designated the slow coronary flow (SCF) phenomenon. Objectives: In this study, we aimed to describe the demographic and clinical findings and presence of common atherosclerosis risk factors in patients with the SCF phenomenon. Patients and Methods: Between October 2014 and March 2015, demographic data, clinical histories, atherosclerosis risk factors, and laboratory and angiographic findings were recorded for all consecutive patients scheduled for coronary angiography and diagnosed with the SCF phenomenon, as well as a control group (patients with normal epicardial coronary arteries; NECA). SCF was diagnosed based on the thrombolysis in myocardial infarction frame count (TFC). A TFC > 27 indicated a diagnosis of SCF phenomenon. Results: Among the 3600 patients scheduled for selective coronary angiography, 75 (2%) met the SCF criteria. SCF and NECA patients did not exhibit statistically significant differences in traditional risk factors except for hypertension, which was more prevalent in SCF than NECA patients (52% versus 31%, P = 0.008). A multivariable analysis indicated a low body mass index, presence of hypertension, low high-density lipoprotein cholesterol (HDL-c) level, and high hemoglobin level as independent predictors of the SCF phenomenon; of these, hypertension was the strongest predictor (odds ratio = 6.3, 95% confidence interval: 2.2 - 17.9, P = 0.001). Conclusions: The SCF phenomenon is relatively frequent, particularly among patients with acute coronary syndrome who are scheduled for coronary angiography. Hypertension, a low HDL-c level, and high hemoglobin level can be considered independent predictors of this phenomenon. PMID:26889458

  5. 21 CFR 862.2150 - Continuous flow sequential multiple chemistry analyzer for clinical use.

    Science.gov (United States)

    2010-04-01

    ... analyzer for clinical use. (a) Identification. A continuous flow sequential multiple chemistry analyzer for... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Continuous flow sequential multiple chemistry analyzer for clinical use. 862.2150 Section 862.2150 Food and Drugs FOOD AND DRUG...

  6. Catheter-based flow measurements in hemodialysis fistulas - Bench testing and clinical performance

    DEFF Research Database (Denmark)

    Heerwagen, Søren T; Lönn, Lars; Schroeder, Torben V;

    2012-01-01

    Purpose: The purpose of this study was to perform bench and clinical testing of a catheter-based intravascular system capable of measuring blood flow in hemodialysis vascular accesses during endovascular procedures. Methods: We tested the Transonic ReoCath Flow Catheter System which uses the ther......Purpose: The purpose of this study was to perform bench and clinical testing of a catheter-based intravascular system capable of measuring blood flow in hemodialysis vascular accesses during endovascular procedures. Methods: We tested the Transonic ReoCath Flow Catheter System which uses...

  7. Management of Low-Flow Vascular Malformations: Clinical Presentation, Classification, Patient Selection, Imaging and Treatment

    Energy Technology Data Exchange (ETDEWEB)

    McCafferty, Ian, E-mail: ian.mccafferty@uhb.nhs.uk [Queen Elizabeth Hospital Birmingham (QEHB) & Birmingham Children’s Hospital (BCH) (United Kingdom)

    2015-10-15

    This review article aims to give an overview of the current state of imaging, patient selection, agents and techniques used in the management of low-flow vascular malformations. The review includes the current classifications for low-flow vascular malformations including the 2014 updates. Clinical presentation and assessment is covered with a detailed section on the common sclerosant agents used to treat low-flow vascular malformations, including dosing and common complications. Imaging is described with a guide to a simple stratification of the use of imaging for diagnosis and interventional techniques.

  8. Management of Low-Flow Vascular Malformations: Clinical Presentation, Classification, Patient Selection, Imaging and Treatment

    International Nuclear Information System (INIS)

    This review article aims to give an overview of the current state of imaging, patient selection, agents and techniques used in the management of low-flow vascular malformations. The review includes the current classifications for low-flow vascular malformations including the 2014 updates. Clinical presentation and assessment is covered with a detailed section on the common sclerosant agents used to treat low-flow vascular malformations, including dosing and common complications. Imaging is described with a guide to a simple stratification of the use of imaging for diagnosis and interventional techniques

  9. Effects of blood flow control on clinical outcomes after ethanolamine oleate sclerotherapy for vascular malformations

    International Nuclear Information System (INIS)

    The purpose of this study was to assess the control of nidus blood flow and the association between such control and clinical outcomes after ethanolamine oleate (EO) sclerotherapy for vascular malformations. Morphological grades on magnetic resonance (MR) images (grades 1-3), preprocedure nidus blood flow control, and clinical results in 22 cases of vascular malformation were reviewed. Cases were subdivided by MR morphological grade as follows: grade 1, 3 patients; grade 2A, 6 patients; grade 3, 13 patients. Responses to EO sclerotherapy were as follows: excellent, 3 patients; good, 5 patients; poor, 14 patients. An excellent response was achieved in one grade 1 case, one grade 2A case, and one grade 3 case. Preprocedure nidus flow was controlled in 8 lesions (type A) and not controlled in 14 lesions (type B). Three (37.5%) type A lesions had an excellent response, five had a good response; and none had a poor response. All type B lesions had a poor response. Flow control predicted an excellent result (P<0.05). Preprocedure nidus blood flow control (versus lack of control) is associated with a significantly higher incidence of favorable clinical responses to EO sclerotherapy for vascular malformations. (author)

  10. Doppler standard deviation imaging for clinical monitoring of in vivo human skin blood flow

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Yonghua; Chen, Zhongping; Saxer, Christopher; Shen, Qimin; Xiang, Shaohua; Boer, Johannes F. de; Nelson, J. Stuart

    2000-09-15

    We used a novel phase-resolved optical Doppler tomographic (ODT) technique with very high flow-velocity sensitivity (10 {mu}m/s) and high spatial resolution (10 {mu}m) to image blood flow in port-wine stain (PWS) birthmarks in human skin. In addition to the regular ODT velocity and structural images, we use the variance of blood flow velocity to map the PWS vessels. Our device combines ODT and therapeutic systems such that PWS blood flow can be monitored in situ before and after laser treatment. To the authors' knowledge this is the first clinical application of ODT to provide a fast semiquantitative evaluation of the efficacy of PWS laser therapy in situ and in real time. (c) 2000 Optical Society of America.

  11. Clinical importance of hyperemic coronary blood flow (thrombolysis in myocardial infarction-intravenous flow) after primary percutaneous coronary intervention.

    Science.gov (United States)

    Karakoyun, Süleyman; Tanboga, Ibrahim Halil; Kurt, Mustafa; Aksakal, Enbiya; Kaya, Ahmet; Isik, Turgay; Ekinci, Mehmet; Sevimli, Serdar; Acikel, Mahmut

    2014-10-01

    We aimed to investigate clinical, demographic and angiographic factors associated with hyperemic coronary blood flow (HCBF) and the relation of HCBF with mortality at 30 days. Our study included 809 consecutive patients with acute ST-segment elevation myocardial infarction who underwent primary percutaneous coronary intervention (PCI). We divided corrected thrombolysis in myocardial infarction (TIMI) frame count (TFC) values into three tertiles: less than 14, 14-28 and more than 28. Corrected TFC less than 14 was defined as HCBF or TIMI intravenous flow. The primary end-point of the present study was all-cause mortality within 30 days. Among the HCBF group (n = 58), the patients with poor myocardial perfusion demonstrated the highest mortality rate within the 30-day follow-up period (33%). Low TIMI myocardial perfusion grade, history of no smoking, left ventricular ejection fraction (LVEF), and high Killip status and low LVEF were found to be independently associated with 1-month all-cause mortality. The present study showed that HCBF after primary PCI has a high 30-day mortality when associated with impaired reperfusion. PMID:24842315

  12. Axial and centrifugal continuous-flow rotary pumps: a translation from pump mechanics to clinical practice.

    Science.gov (United States)

    Moazami, Nader; Fukamachi, Kiyotaka; Kobayashi, Mariko; Smedira, Nicholas G; Hoercher, Katherine J; Massiello, Alex; Lee, Sangjin; Horvath, David J; Starling, Randall C

    2013-01-01

    The recent success of continuous-flow circulatory support devices has led to the growing acceptance of these devices as a viable therapeutic option for end-stage heart failure patients who are not responsive to current pharmacologic and electrophysiologic therapies. This article defines and clarifies the major classification of these pumps as axial or centrifugal continuous-flow devices by discussing the difference in their inherent mechanics and describing how these features translate clinically to pump selection and patient management issues. Axial vs centrifugal pump and bearing design, theory of operation, hydrodynamic performance, and current vs flow relationships are discussed. A review of axial vs centrifugal physiology, pre-load and after-load sensitivity, flow pulsatility, and issues related to automatic physiologic control and suction prevention algorithms is offered. Reliability and biocompatibility of the two types of pumps are reviewed from the perspectives of mechanical wear, implant life, hemolysis, and pump deposition. Finally, a glimpse into the future of continuous-flow technologies is presented.

  13. [Clinical application and experimental studies of the pulsed inhaled nitric oxide flow controlling instrument].

    Science.gov (United States)

    Mo, Xu-ming; Zhao, En-chun; Wang, Min-sheng; Gu, Xinglin; Wang, Zhenxi; Wang, Chunsheng

    2002-01-01

    A flow controlling system for pulsed inhaled nitric oxide has been developed and tested, and here its features and initial animal experiments and clinical applications are described. The physical characteristic test indicates that the practical released dose of NO gas is very close to the theoretical flow of NO gas at variant pressures. Animal experiments demonstrate that inhaled NO gas concentration is lower than the concentration of theoretical inhalation, but the variance is not remarkable (p>0.05). When sixteen cases with CHD and PH were chosen to inhale NO gas (15 ppm, 15 min) PAP and PVR of all cases were reduced after inhalation of NO gas from 617 +/-51.3 dyn x s x cm(-5), 54.4+/-13.1 mmHg to 417+/-36.9 dym x s x cm(-5), 33.8+/-12.3 mmHg (PVR, p<0.01; PAP, p<0.01) respectively. When gas inhalation was stopped, these values returned to their base lines after a short period of time. All these show that the pulsed inhaled NO flow controlling instrument in accordance with the requirements of the designing, can be widely used in clinical diagnoses and treatments and will be a new tool offered for the treatments of the patients with PH. PMID:16104155

  14. Immune Monitoring in Cancer Vaccine Clinical Trials: Critical Issues of Functional Flow Cytometry-Based Assays

    Directory of Open Access Journals (Sweden)

    Iole Macchia

    2013-01-01

    Full Text Available The development of immune monitoring assays is essential to determine the immune responses against tumor-specific antigens (TSAs and tumor-associated antigens (TAAs and their possible correlation with clinical outcome in cancer patients receiving immunotherapies. Despite the wide range of techniques used, to date these assays have not shown consistent results among clinical trials and failed to define surrogate markers of clinical efficacy to antitumor vaccines. Multiparameter flow cytometry- (FCM- based assays combining different phenotypic and functional markers have been developed in the past decade for informative and longitudinal analysis of polyfunctional T-cells. These technologies were designed to address the complexity and functional heterogeneity of cancer biology and cellular immunity and to define biomarkers predicting clinical response to anticancer treatment. So far, there is still a lack of standardization of some of these immunological tests. The aim of this review is to overview the latest technologies for immune monitoring and to highlight critical steps involved in some of the FCM-based cellular immune assays. In particular, our laboratory is focused on melanoma vaccine research and thus our main goal was the validation of a functional multiparameter test (FMT combining different functional and lineage markers to be applied in clinical trials involving patients with melanoma.

  15. Laser speckle contrast imaging of cerebral blood flow in humans during neurosurgery: a pilot clinical study

    Science.gov (United States)

    Parthasarathy, Ashwin B.; Weber, Erica L.; Richards, Lisa M.; Fox, Douglas J.; Dunn, Andrew K.

    2010-11-01

    Monitoring cerebral blood flow (CBF) during neurosurgery can provide important physiological information for a variety of surgical procedures. CBF measurements are important for assessing whether blood flow has returned to presurgical baseline levels and for assessing postsurgical tissue viability. Existing techniques for intraoperative monitoring of CBF based on magnetic resonance imaging are expensive and often impractical, while techniques such as indocyanine green angiography cannot produce quantitative measures of blood flow. Laser speckle contrast imaging (LSCI) is an optical technique that has been widely used to quantitatively image relative CBF in animal models in vivo. In a pilot clinical study, we adapted an existing neurosurgical operating microscope to obtain LSCI images in humans in real time during neurosurgery under baseline conditions and after bipolar cautery. Simultaneously recorded ECG waveforms from the patient were used to develop a filter that helped reduce measurement variabilities due to motion artifacts. Results from this study demonstrate the feasibility of using LSCI to obtain blood flow images during neurosurgeries and its capability to produce full field CBF image maps with excellent spatial resolution in real-time with minimal disruption to the surgical procedure.

  16. Clinical evaluation of simple fixed space maintainers bonded with flow composite resin.

    Science.gov (United States)

    Simsek, Sera; Yilmaz, Yucel; Gurbuz, Taskin

    2004-01-01

    The aim of this study was to evaluate the clinical performance of simple fixed space maintainers bonded by using a flow composite resin (Tetric Flow) to prevent space resulting from early extracted primary teeth. For that reason, 64 fixed space maintainers (34 in the lower jaw and 30 in the upper jaw) were applied to 45 patients. The patients followed up for 12 to 18 months. Survival rate, prevention ability of that space, and whether damage to the abutment teeth occurred were evaluated. Five percent of space maintainers were determined to be unsuccessful at the end of the control period. During this period, loss of space among the abutment teeth was found to be statistically insignificant (P > .05). Finally, it was observed that the use of simple fixed space maintainers was successful due to operator experience and the choosing of favorable patient groups.

  17. Improved graft survival in highly sensitized patients undergoing renal transplantation after the introduction of a clinically validated flow cytometry crossmatch.

    LENUS (Irish Health Repository)

    Limaye, Sandhya

    2009-04-15

    Flow cytometric techniques are increasingly used in pretransplant crossmatching, although there remains debate regarding the clinical significance and predictive value of donor-specific antibodies detected by flow cytometry. At least some of the discrepancies between published studies may arise from differences in cutoffs used and lack of standardization of the test.

  18. INCIDENCE OF SUB - CLINICAL AIRFLOW OBSTRUCTION IN APPARENTLY HEALTHY MEDICAL PERSONNEL; DIAGNOSIS AND COMPARISION BY SPIROMETRY AND PEAK FLOW METRY

    OpenAIRE

    Subba Rao; Aruna; Sateesh Kumar; Neethi Chandra

    2015-01-01

    AIM & OBJE CTIVES OF THE STUDY: To diagnose sub - clinical airflow obstruction in apparently healthy medical personnel, and to compare Peak Expiratory Flow Rate (PEFR) by using Spirometry and by Wright’s peak flow meter. METHODOLOGY: About 80 apparently healthy medical students including Post Graduates, internees and medical technicians were taken in ...

  19. Clinical effect of Diskus dry-powder inhaler at low and high inspiratory flow-rates in asthmatic children

    DEFF Research Database (Denmark)

    Nielsen, K G; Auk, I L; Bojsen, K;

    1998-01-01

    at low (30 L x min[-1]) and high (90 L x min[-1]) flow rates. A pilot study in 129 children aged 3-10 yrs demonstrated that 99% of children of 3 yrs and above can generate a flow > or = 30 L x min(-1) through the device, while 26% performed > or = 90 L x min(-1). Eighteen children aged 8-15 yrs...... clinical effect at low and high flow rates in children....

  20. DETECTION OF PLATELET-DERIVED MICROPARTICLES USING FLOW CYTOMETRY AND ITS CLINICAL APPLICATION

    Institute of Scientific and Technical Information of China (English)

    崔巍; 马文新; 韩晔华; 林其燧

    2003-01-01

    Objective.To establish a flow cytometric internal standard method for counting platelet-derived microparti-cles(PMPs)and to study its clinical significance. Methods. PMPs suspension(platelet poor plasma,PPP) was extracted by gradual centrifugation. According to the size of PMPs,3 μm and 0.8μm latex beads were used as internal standards for the quantitation. PMPs were counted by adjusting flow cytometric discrimination and voltage of forward scatter and side scatter. Results. In 30 healthy donors,the average concentration of resting PMPs was(1.2×105±5.7×104 )/ml and that of activated PMPs was(1.6×106±9.1×105)/ml. Compared with healthy donors,PMPs mean value was significantly higher(P0.05)] .Conclusions. PMPs is a useful indicator in monitoring platelet activation,and plays an important role in thrombotic disease. By flow cytometric internal standard method,PMPs can be counted rapidly and accurately,which may be very helpful in interlaboratory comparative studies.

  1. Magnetic resonance imaging flow void changes after cerebrospinal fluid shunt in post-traumatic hydrocephalus: clinical correlations and outcome.

    Science.gov (United States)

    Missori, Paolo; Miscusi, Massimo; Formisano, Rita; Peschillo, Simone; Polli, Filippo M; Melone, Antonio; Martini, Stefano; Paolini, Sergio; Delfini, Roberto

    2006-07-01

    The assessment of the flow-void in the cerebral aqueduct of patients with post-traumatic hydrocephalus on magnetic resonance imaging (MRI) evaluation could concur the right diagnosis and have a prognostic value. We analysed prospectively 28 patients after a severe head injury (GCSclinical suspicion of post-traumatic hydrocephalus and a fast flow-void signal in the cerebral acqueduct on T2-weighted and proton density MRI. Twenty-two patients were shunted (n=19) or revised (n=3). Six patients were followed-up without surgery. Twenty out of 22 shunted patients (91%) showed variable reduction of the fast flow-void. Eighteen of the operated patients (82%) presented a significant clinical improvement at 6-month follow-up. All patients (n=2) who had no change of the fast flow-void after surgery did not clinically improve. The six non-shunted patients did not present any clinical or radiological improvement. In head-injured patients, fast flow-void in the cerebral aqueduct is diagnostic for post-traumatic hydrocephalus and its reduction after ventriculo-peritoneal shunt is correlated with a neurological improvement. In already shunted patients, a persistent fast flow-void is associated with a lack of or very slow clinical improvement and it should be considered indicative of under-drainage.

  2. Clinical Relevance of Coronary Fractional Flow Reserve: Art-of-state

    Institute of Scientific and Technical Information of China (English)

    Yohanes Adiputra; Shao-Liang Chen

    2015-01-01

    Objective:The objective was to delineate the current knowledge of fractional flow reserve (FFR) in terms of definition,features,clinical applications,and pitfalls of measurement of FFR.Data Sources:We searched database for primary studies published in English.The database of National Library of Medicine (NLM),MEDLINE,and PubMed up to July 2014 was used to conduct a search using the keyword term "FFR".Study Selection:The articles about the definition,features,clinical application,and pitfalls of measurement of FFR were identified,retrieved,and reviewed.Results:Coronary pressure-derived FFR rapidly assesses the hemodynamic significance of individual coronary artery lesions and can readily be performed in the catheterization laboratory.The use of FFR has been shown to effectively guide coronary revascularization procedures leading to improved patient outcomes.Conclusions:FFR is a valuable tool to determine the functional significance of coronary stenosis.It combines physiological and anatomical information,and can be followed immediately by percutaneous coronary intervention (PCI) if necessary.The technique of FFR measurement can be performed easily,rapidly,and safely in the catheterization laboratory.By systematic use of FFR in dubious stenosis and multi-vessel disease,PCI can be made an even more effective and better treatment than it is currently.The current clinical evidence for FFR should encourage cardiologists to use this tool in the catheterization laboratory.

  3. Clinical evaluation of pulsatile flow mode of Terumo Capiox centrifugal pump.

    Science.gov (United States)

    Nishida, H; Uesugi, H; Nishinaka, T; Uwabe, K; Aomi, S; Endo, M; Koyanagi, H; Oshiyama, H; Nogawa, A; Akutsu, T

    1997-07-01

    The Terumo Capiox centrifugal pump system possesses an automatic priming function in which the motor repeatedly stops and runs intermittently to eliminate air bubbles in the circuit through the micropores of the hollow-fiber membrane oxygenator. By modifying this mechanism, we have developed a pulsatile flow mode. In this mode, maximum and minimum pump rotational speeds can be independently set every 20 rpm in the range of 0 to 3,000 rpm. The duration of the pump run at maximum and minimum speeds can also be independently set every 0.1 s in the range of 0.2 to 15 s. In a clinical trial, after obtaining the desired flow rate, 2.4 L/min/m2 in nonpulsatile flow mode, a pulsatile flow mode of 60 cycles/min (with 1 cycle being maximum speed for 0.4 s and minimum speed for 0.6 s) was obtained by adding and subtracting 500 rpm to and from the rotational speed in nonpulsatile flow mode. Pulse pressures in the femoral artery and in the circuit just proximal to the perfusion cannula (6.5 mm Sarns high flow cannula with metal tip) were measured in 5 patients who underwent pulsatile cardiopulmonary bypass (CPB) for a coronary artery bypass graft (CABG), and compared to pulse pressures obtained by intraaortic balloon pumping (IABP) in 3 patients and by the pulsatile mode of the 3M Delphin pump in 3 patients. The platelet count, free hemoglobin, and beta-thromboglobulin (beta-TG) were measured and compared with measurements from another 5 patients who underwent nonpulsatile CPB. Although the pulse pressure measured in the circuit was 180 mm Hg on average, the pressure in the femoral artery was only 15 to 40 mm Hg with a mean of 20 mm Hg. In the same patients, 60 to 80 mm Hg pulse pressure was obtained with IABP. The pulse pressure obtained with the Delphin pump was not more than that obtained with the Terumo pump. There were no significant differences in percents of preoperative levels of platelet counts (pulsatile, 87.6 +/- 15.8% and nonpulsatile, 72.4 +/- 40.6%), free

  4. Practical way to develop 10-color flow cytometry protocols for the clinical laboratory

    Science.gov (United States)

    Tárnok, Attila; Bocsi, Jozsef

    2010-02-01

    The latest development of commercial routine flow cytometers (FCM) is that they are equipped with three (blue, red, violet) or more lasers and many PMT detectors. Nowadays routine clinical instruments are capable of detecting 10 or more fluorescence colors simultaneously. Thereby, presenting opportunities for getting detailed information on the single cell level for cytomics and systems biology for improve diagnostics and monitoring of patients. The University Leipzig, Germany) recently started a cluster of excellence to study the molecular background of life style and environment associated diseases, enrolling 25000 individuals (LIFE). To this end the most comprehensive FCM protocol has to be developed for this study. We aimed to optimize fluorochrome and antibody combinations to the characteristics of the instrument for successful 10-color FCM. Systematic review of issues related to sampling, preparation, instrument settings, spillover and compensation matrix, reagent performance, and general principles of panel construction was performed. 10-color FCM enables for increased accuracy in cell subpopulation identification, the ability to obtain detailed information from blood specimens, improved laboratory efficiency, and the means to consistently detect major and rare cell populations. Careful attention to details of instrument and reagent performance allows for the development of panels suitable for screening of samples from healthy and diseased donors. The characteristics of this technique are particularly well suited for the analysis of broad human population cohorts and have the potential to reach the everyday practice in a standardized way for the clinical laboratory.

  5. Flow

    DEFF Research Database (Denmark)

    2009-01-01

    Flow er en positiv, koncentreret tilstand, hvor al opmærksomhed er samlet om en bestemt aktivitet, som er så krævende og engagerende, at man må anvende mange mentale ressourcer for at klare den. Tidsfornemmelsen forsvinder, og man glemmer sig selv. 'Flow' er den første af en række udsendelser om...

  6. Integration of Quantitative Positron Emission Tomography Absolute Myocardial Blood Flow Measurements in the Clinical Management of Coronary Artery Disease.

    Science.gov (United States)

    Gewirtz, Henry; Dilsizian, Vasken

    2016-05-31

    In the >40 years since planar myocardial imaging with(43)K-potassium was introduced into clinical research and management of patients with coronary artery disease (CAD), diagnosis and treatment have undergone profound scientific and technological changes. One such innovation is the current state-of-the-art hardware and software for positron emission tomography myocardial perfusion imaging, which has advanced it from a strictly research-oriented modality to a clinically valuable tool. This review traces the evolving role of quantitative positron emission tomography measurements of myocardial blood flow in the evaluation and management of patients with CAD. It presents methodology, currently or soon to be available, that offers a paradigm shift in CAD management. Heretofore, radionuclide myocardial perfusion imaging has been primarily qualitative or at best semiquantitative in nature, assessing regional perfusion in relative terms. Thus, unlike so many facets of modern cardiovascular practice and CAD management, which depend, for example, on absolute values of key parameters such as arterial and left ventricular pressures, serum lipoprotein, and other biomarker levels, the absolute levels of rest and maximal myocardial blood flow have yet to be incorporated into routine clinical practice even in most positron emission tomography centers where the potential to do so exists. Accordingly, this review focuses on potential value added for improving clinical CAD practice by measuring the absolute level of rest and maximal myocardial blood flow. Physiological principles and imaging fundamentals necessary to understand how positron emission tomography makes robust, quantitative measurements of myocardial blood flow possible are highlighted.

  7. Integration of Quantitative Positron Emission Tomography Absolute Myocardial Blood Flow Measurements in the Clinical Management of Coronary Artery Disease.

    Science.gov (United States)

    Gewirtz, Henry; Dilsizian, Vasken

    2016-05-31

    In the >40 years since planar myocardial imaging with(43)K-potassium was introduced into clinical research and management of patients with coronary artery disease (CAD), diagnosis and treatment have undergone profound scientific and technological changes. One such innovation is the current state-of-the-art hardware and software for positron emission tomography myocardial perfusion imaging, which has advanced it from a strictly research-oriented modality to a clinically valuable tool. This review traces the evolving role of quantitative positron emission tomography measurements of myocardial blood flow in the evaluation and management of patients with CAD. It presents methodology, currently or soon to be available, that offers a paradigm shift in CAD management. Heretofore, radionuclide myocardial perfusion imaging has been primarily qualitative or at best semiquantitative in nature, assessing regional perfusion in relative terms. Thus, unlike so many facets of modern cardiovascular practice and CAD management, which depend, for example, on absolute values of key parameters such as arterial and left ventricular pressures, serum lipoprotein, and other biomarker levels, the absolute levels of rest and maximal myocardial blood flow have yet to be incorporated into routine clinical practice even in most positron emission tomography centers where the potential to do so exists. Accordingly, this review focuses on potential value added for improving clinical CAD practice by measuring the absolute level of rest and maximal myocardial blood flow. Physiological principles and imaging fundamentals necessary to understand how positron emission tomography makes robust, quantitative measurements of myocardial blood flow possible are highlighted. PMID:27245647

  8. Lactate solid-state biosensor with multilayer of electrodeposited polymers for flow-injection clinical analysis.

    Science.gov (United States)

    Krawczyñski vel Krawczyk, T; Trojanowicz, M; Lewenstam, M; Moszczynska, A

    1996-01-01

    In the lactate biosensor, electrodeposited poly(o-phenylenediamine) serves as a convenient matrix for the immobilization of lactate oxidase, but does not provide sufficient discrimination from several interfering species present in physiological fluids. Their effect, however, can be eliminated by additional modification of the working Pt electrode with a bilayer of electrodeposited polypyrrole/polyphenol. Despite continued decrease in biosensor sensitivity, the newly developed three-layer solid-state biosensor was successfully applied in flow-injection determination of lactate in both undiluted and diluted human blood serum samples over a 10 day period. For the lactate concentration range 0.2-5.0 mM in several series of measurements the correlation coefficient values for comparison with photometric determination using a DuPont dimension clinical analyzer were between 0.96 and 0.99. The reproducibility measured for 1:10 diluted serum was 0.6%. The detection limit was estimated as 2 microM. PMID:8828166

  9. Flow

    DEFF Research Database (Denmark)

    Knoop, Hans Henrik

    2006-01-01

    FLOW. Orden i hovedet på den fede måde Oplevelsesmæssigt er flow-tilstanden kendetegnet ved at man er fuldstændig involveret, fokuseret og koncentreret; at man oplever stor indre klarhed ved at vide hvad der skal gøres, og i hvilket omfang det lykkes; at man ved at det er muligt at løse opgaven...

  10. Regulation of peripheral blood flow in Complex Regional Pain Syndrome: clinical implication for symptomatic relief and pain management

    Directory of Open Access Journals (Sweden)

    Coderre Terence J

    2009-09-01

    Full Text Available Abstract Background During the chronic stage of Complex Regional Pain Syndrome (CRPS, impaired microcirculation is related to increased vasoconstriction, tissue hypoxia, and metabolic tissue acidosis in the affected limb. Several mechanisms may be responsible for the ischemia and pain in chronic cold CPRS. Discussion The diminished blood flow may be caused by either sympathetic dysfunction, hypersensitivity to circulating catecholamines, or endothelial dysfunction. The pain may be of neuropathic, inflammatory, nociceptive, or functional nature, or of mixed origin. Summary The origin of the pain should be the basis of the symptomatic therapy. Since the difference in temperature between both hands fluctuates over time in cold CRPS, when in doubt, the clinician should prioritize the patient's report of a persistent cold extremity over clinical tests that show no difference. Future research should focus on developing easily applied methods for clinical use to differentiate between central and peripheral blood flow regulation disorders in individual patients.

  11. Clinical utility of far-infrared therapy for improvement of vascular access blood flow and pain control in hemodialysis patients

    OpenAIRE

    Choi, Soo Jeong; Cho, Eun Hee; Jo, Hye Min; Min, Changwook; Ji, Young Sok; Park, Moo Yong; Kim, Jin Kuk; Hwang, Seung Duk

    2015-01-01

    Background Maintenance of a well-functioning vascular access and minimal needling pain are important goals for achieving adequate dialysis and improving the quality of life in hemodialysis (HD) patients. Far-infrared (FIR) therapy may improve endothelial function and increase access blood flow (Qa) and patency in HD patients. The aim of this study was to evaluate effects of FIR therapy on Qa and patency, and needling pain in HD patients. Methods This prospective clinical trial enrolled 25 out...

  12. 78 FR 5186 - Clinical Flow Cytometry in Hematologic Malignancies; Public Workshop; Request for Comments

    Science.gov (United States)

    2013-01-24

    ... monoclonal antibodies and flow cytometry contributed to the automation of lymphocyte subset analysis. Flow cytometric lymphocyte subset analysis was initially used to immunophenotype hematological malignancies; however, the HIV epidemic led to a large number of 510(k) submissions addressing use for HIV...

  13. Value of venous color flow duplex scan as initial screening test for geriatric inpatients with clinically suspected pulmonary embolism

    Directory of Open Access Journals (Sweden)

    Kreidy R

    2011-09-01

    Full Text Available Raghid Kreidy1, Elias Stephan2, Pascale Salameh3, Mirna Waked4 1Department of Vascular Surgery, Saint George Hospital, University Medical Center, University of Balamand, Beirut, Lebanon; 2Department of Geriatrics, Saint George Hospital, University Medical Center, University of Balamand, Beirut, Lebanon; 3Laboratory of Clinical and Epidemiological Research, Faculty of Pharmacy, Lebanese University, 4Department of Pulmonary Medicine, Saint George Hospital, University Medical Center, University of Balamand, Beirut, Lebanon Aim: The contribution of lower extremity venous duplex scan to the diagnostic strategy for pulmonary embolism has been demonstrated by many authors. However, the positive diagnostic value of this noninvasive test in clinically suspected pulmonary embolism is not very high (10%–18%. Since thromboembolic risks increase considerably in hospitalized patients with advanced age, this study aims to determine the importance of lower extremity venous color flow duplex scan in this particular subgroup of patients with clinically suspected pulmonary embolism. The effects of clinical presentation and risk factors on the results of duplex scan have been also studied. Methods: Between July 2007 and January 2010, 95 consecutive Lebanese geriatric ($60 years of age inpatients with clinically suspected pulmonary embolism assessed in an academic tertiary-care center for complete lower extremity venous color flow duplex scan were retrospectively reviewed. Age varied between 60 and 96 years (mean, 79.9 years. Forty patients were males and 55 females. Absence of compressibility was the most important criteria for detecting acute venous thrombosis. Results: Out of 95 patients, 33 patients (34.7% were diagnosed with recent deep venous thrombosis of lower extremities (14 proximal and 19 distal using complete venous ultrasound. Nine of these 33 patients (27.2% had a history of venous thromboembolism and eleven (33.3% presented with edema of lower

  14. Clinical and Experimental Study of Effects of Rhubarb on Gastrointestinal Blood Flow Perfusion in Critical Illness

    Institute of Scientific and Technical Information of China (English)

    CHEN; De-chang

    2001-01-01

    [1]Border JR. Multiple system organ failure. Ann Surg 1992;216(2)∶111-116.[2]Schiessel R, Feil W, Wenzel E. Mechanisms of stress ulceration and implications for treatment. Gastroenterol Clin North Am 1990;19(1)∶101-120.[3]CHEN DC, YANG JD, YANG XY, et al. The effects of rhubarb on permeability of intestinal mucosa and blood vessel in shocked rats. Chin Crit Care Med 1997;9(7)∶385-387.[4]CHEN DC, JING BW. The effects of rhubarb on the protection of gut barrier. Chin Crit Care Med 1994;6(6)∶329-331.[5]American College of Chest Physician/Society of Critical Care Medicine Consensus: Definitions for sepsis and organ failure and guidelines for the use of innovative therapies in sepsis. Crit Care Med 1992;20(6)∶864-874.[6]CHEN DC, JING BW, YANG XY, et al. Therapeutic effects of rhubarb on gastrointestinal failure. Med J Chin PLA 1996;21(1)∶24-26.[7]Nakayama SE. Infusion of very hypertonic saline to bled rats: membrane potential and fluid shifts. J Surg Res 1985;38(2)∶180-186.[8]Bulkley GB. Relationship of blood flow and oxygen consumption to ischemic injury in the canine small intestine. Gastroenterology 1985;89(4)∶852-857.[9]Marshall JC, Christon NV, Meakins JL, et al. The gastrointestinal tract: The “undrained abscess” of multiple organ failure. Ann Surg 1993;218(2)∶111-119.[10].Fiddiann-Green RG, McGough E, Pittenger G, et al. Predictive value of intramural pH and other risk factors for massive bleeding from stress ulceration. Gastroenterology. 1983;85(3)∶613-620.[11].ZHU L, YANG ZC, LI A. Changes and significance of the ability of gastric acid excretion during burn shock in rats. Chin Crit Care Med 1997;9(7)∶398-399.[12].JIAO DH, CHEN SX, ZHANG GH, et al. Clinical study of the effects of rhubarb on peptic ulcer with hemorrhage. CJITWM 1984;10(10)∶597-599.[13].YU JD, GONG LS. Effects of rhubarb on thromboxane A2 and prostacyclin in circulation blood in healthy people and acute myocardial

  15. Clinical effectiveness of centrifugal pump to produce pulsatile flow during cardiopulmonary bypass in patients undergoing cardiac surgery.

    Science.gov (United States)

    Gu, Y John; van Oeveren, Willem; Mungroop, Hubert E; Epema, Anne H; den Hamer, Inez J; Keizer, Jorrit J; Leuvenink, Ron P; Mariani, Massimo A; Rakhorst, Gerhard

    2011-02-01

    Although the centrifugal pump has been widely used as a nonpulsatile pump for cardiopulmonary bypass (CPB), little is known about its performance as a pulsatile pump for CPB, especially on its efficacy in producing hemodynamic energy and its clinical effectiveness. We performed a study to evaluate whether the Rotaflow centrifugal pump produces effective pulsatile flow during CPB and whether the pulsatile flow in this setting is clinically effective in adult patients undergoing cardiac surgery. Thirty-two patients undergoing CPB for elective coronary artery bypass grafting were randomly allocated to a pulsatile perfusion group (n = 16) or a nonpulsatile perfusion group (n = 16). All patients were perfused with the Rotaflow centrifugal pump. In the pulsatile group, the centrifugal pump was adjusted to the pulsatile mode (60 cycles/min) during aortic cross-clamping, whereas in the nonpulsatile group, the pump was kept in its nonpulsatile mode during the same period of time. Compared with the nonpulsatile group, the pulsatile group had a higher pulse pressure (P centrifugal pump is associated with a small gain of EEP and SHE, which does not seem to be clinically effective in adult cardiac surgical patients.

  16. Designed to fail: how computer simulation can detect fundamental flaws in clinic flow.

    Science.gov (United States)

    Parks, Jennifer Kaye; Engblom, Patricia; Hamrock, Eric; Satjapot, Siriporn; Levin, Scott

    2011-01-01

    Discrete-event simulation can be used as an effective tool for healthcare administrators to "test" various operational decisions. The recent growth in hospital outpatient volumes and a constrained financial environment make discrete-event simulation a cost-effective way to diagnose inefficiency and create and test strategies for improvement. This study shows how discrete-event simulation was used in an adult medicine clinic within a large, tertiary care, academic medical center. Simulation creation steps are discussed, including information gathering, process mapping, data collection, model creation, and results. Results of the simulation indicated that system bottle-necks were present in the medication administration and check-out steps of the clinic process. The simulation predicted that matching resources to excessive demand at appropriate times for these bottleneck steps would reduce patients' mean time in the system (i.e., visit time) from 124.3 (s.d. +/- 65.7) minutes to 87.0 (s.d. +/- 36.4) minutes. Although other factors may affect real-world operations of a clinic, discrete-event simulation allows healthcare administrators and clinic operational decision makers to observe the effects of changing staffing and resource allocations on patient wait and throughput time. Discrete-event simulation is not a cure-all for clinic throughput problems, but can be a strong tool to provide evidentiary guidance for clinic operational redesign. PMID:21495531

  17. Synthesis of [18F]FMISO in a flow-through microfluidic reactor: Development and clinical application

    International Nuclear Information System (INIS)

    Introduction: The PET radiotracer [18F]FMISO has been used in the clinic to image hypoxia in tumors. The aim of the present study was to optimize the radiochemical parameters for the preparation of [18F]FMISO using a microfluidic reaction system. The main parameters evaluated were (1) precursor concentration, (2) reaction temperature, and (3) flow rate through the microfluidic reactor. Optimized conditions were then applied to the batch production of [18F]FMISO for clinical research use. Methods: For the determination of optimal reaction conditions within a flow-through microreactor synthesizer, 5–400 μL the precursor and dried [18F]fluoride solutions in acetonitrile were simultaneously pushed through the temperature-controlled reactor (60–180 °C) with defined flow rates (20–120 μL/min). Radiochemical incorporation yields to form the intermediate species were determined using radio-TLC. Hydrolysis to remove the protecting group was performed following standard vial chemistry to afford [18F]FMISO. Results: Optimum reaction parameters for the microfluidic set-up were determined as follows: 4 mg/mL of precursor, 170 °C, and 100 μL/min pump rate per reactant (200 μL/min reaction overall flow rate) to prepare the radiolabeled intermediate. The optimum hydrolysis condition was determined to be 2 N HCl for 5 min at 100 °C. Large-scale batch production using the optimized conditions gave the final, ready for human injection [18F]FMISO product in 28.4 ± 3.0% radiochemical yield, specific activity of 119 ± 26 GBq/μmol, and > 99% radiochemical and chemical purity at the end of synthesis (n = 4). Conclusion: By using the NanoTek microfluidic synthesis system, [18F]FMISO was successfully prepared with good specific activity and high radiochemical purity for human use. The product generated from large-scale batch production using flow chemistry is currently being used in clinical research

  18. Clinical values of intraoperative indocyanine green fluorescence video angiography with Flow 800 software in cerebrovascular surgery

    Institute of Scientific and Technical Information of China (English)

    YE Xun; LIU Xing-ju; MA Li; LIU Ling-tong; WANG Wen-lei; WANG Shuo; CAO Yong

    2013-01-01

    Background Microscope-integrated near-infrared indocyanine green video angiography (ICG-VA) has been used in neurosurgery for a decade.This study aimed to assess the value of intraoperative indocyanine green (ICG) video angiography with Flow 800 software in cerebrovascular surgery and to discover its hemodynamic features and changes of cerebrovascular diseases during surgery.Methods A total of 87 patients who received ICG-VA during various surgical procedures were enrolled in this study.Among them,45 cases were cerebral aneurysms,25 were cerebral arteriovenous malformations (AVMs),and 17 were moyamoya disease (MMD).A surgical microscope integrating an infrared fluorescence module was used to confirm the residual aneurysms and blocking of perforating arteries in aneurysms.Feeder arteries,draining veins,and normal cortical vessels were identified by the time delay color mode of Flow 800 software.Hemodynamic parameters were recorded.All data were analyzed by SPSS version 18.0 (SPSS Inc.,USA).T-test was used to analyze the hemodynamic features of AVMs and MMDs,the influence on peripheral cortex after resection in AVMs,and superficial temporal artery to middle cerebral artery (STA-MCA) bypass in MMDs.Results The visual delay map obtained by Flow 800 software had more advantages than the traditional playback mode in identifying the feeder arteries,draining veins,and their relations to normal cortex vessels.The maximum fluorescence intensity (MFI) and the slope of ICG fluorescence curve of feeder arteries and draining veins were higher than normal peripheral vessels (MFI:584.24±85.86 vs.382.94±91.50,slope:144.95±38.08 vs.69.20±13.08,P <0.05).The artefiovenous transit time in AVM was significantly shorter than in normal cortical vessels ((0.60±0.27) vs.(2.08±1.42) seconds,P <0.05).After resection of AVM,the slope of artery in the cortex increased,which reflected the increased cerebral flow.In patients with MMD,after STA-MCA bypass,cortex perfusion of

  19. Coronary Flow Velocity Reserve in Burn Injury: A Prospective Clinical Cohort Study.

    Science.gov (United States)

    Caliskan, Mustafa; Turk, Emin; Karagulle, Erdal; Ciftci, Ozgur; Oguz, Hakan; Kostek, Osman; Moray, Gokhan; Haberal, Mehmet

    2016-01-01

    The authors sought to evaluate coronary microvascular function and left ventricular diastolic dysfunction using transthoracic Doppler echocardiography in burn patients. In this study, 32 adult burn patients with partial or full-thickness scald burns that were hospitalized and treated were included. The control group was matched for age and sex and was composed of otherwise healthy volunteers. Transthoracic Doppler echocardiography examinations and simultaneous laboratory tests for cardiac evaluation were performed on the sixth month after burn injury as well as with the control group. High-sensitivity C-reactive protein levels were significantly higher in the burn patients than in controls (5.17 ± 3.86 vs 2.42 ± 1.78; P = .001). Lateral isovolumic relaxation time was significantly higher in the burn injury group than in the control group (92.7 ± 15.7 vs 85.5 ± 8.3; P = .03). Baseline coronary diastolic peak flow velocity of the left anterior descending artery was similar in both groups. However, hyperemic diastolic peak flow velocity and coronary flow velocity reserve (2.26 ± 0.48 vs 2.94 ± 0.47; P < .001) were significantly lower in the burn injury group than in the control group. Coronary flow velocity reserve was significantly and inversely correlated with high-sensitivity C-reactive protein, burn ratio, creatinine, and mitral A-wave max velocity. At the sixth month of treatment, burn patients had high-sensitivity C-reactive protein levels during this period, suggesting that inflammation still exists. In addition, subclinical coronary microvascular and left ventricular diastolic dysfunction can occur in burn patients without traditional cardiovascular risk factors. However, these results must be supported by additional studies.

  20. Doppler derived quantitative flow estimate in coronary artery bypass graft: a computational multiscale model for the evaluation of the current clinical procedure.

    Science.gov (United States)

    Ponzini, Raffaele; Lemma, Massimo; Morbiducci, Umberto; Montevecchi, Franco M; Redaelli, Alberto

    2008-09-01

    In order to investigate the reliability of the so called mean velocity/vessel area formula adopted in clinical practice for the estimation of the flow rate using an intravascular Doppler guide wire instrumentation, a multiscale computational model was used to give detailed predictions on flow profiles within Y-shaped coronary artery bypass graft (CABG) models. At this purpose three CABG models were built from clinical patient's data and used to evaluate and compare, in each model, the computed flow rate and the flow rate estimated according to the assumption of parabolic velocity profile. A consistent difference between the exact and the estimated value of the flow rate was found in every branch of all the graft models. In this study we showed that this discrepancy in the flow rate estimation is coherent to the theory of Womersley regarding spatial velocity profiles in unsteady flow conditions. In particular this work put in evidence that the error in flow rate estimation can be reduced by using the estimation formula recently proposed by Ponzini et al. [Ponzini R, Vergara C, Redaelli A, Veneziani A. Reliable CFD-based estimation of flow rate in haemodynamics measures. Ultrasound Med Biol 2006;32(10):1545-55], accounting for the unsteady nature of blood, applicable in the clinical practice without resorting to further measurements. PMID:17980641

  1. Exhaled nitric oxide measure using multiple flows in clinically relevant subgroups of COPD

    DEFF Research Database (Denmark)

    Roberts, Nassim Bazeghi; Gerds, Thomas A; Budtz-Jørgensen, Esben;

    2011-01-01

    Although there is widespread interest in fractional exhaled nitric oxide (FeNO) as a non-invasive, time and cost effective biomarker for assessing airway inflammation in chronic obstructive pulmonary disease (COPD), its usefulness is still controversial. We examined the FeNO levels in clinically ...

  2. Cerebral blood flow and oxygenation in infants after birth asphyxia. Clinically useful information?

    DEFF Research Database (Denmark)

    Greisen, Gorm

    2014-01-01

    perfusion and lack of normal cerebral blood flow regulation are also typically present, but whether the perfusion abnormalities at this secondary stage are detrimental, beneficial, or a mere epiphenomenon remains elusive. In contrast, incomplete reoxygenation of the brain during and following resuscitation......The term 'luxury perfusion' was coined nearly 50 years ago after observation of bright-red blood in the cerebral veins of adults with various brain pathologies. The bright-red blood represents decreased oxygen extraction and hence the perfusion is 'luxurious' compared to oxygen needs. Gradual loss...

  3. Tree-Based Methods for Discovery of Association between Flow Cytometry Data and Clinical Endpoints.

    Science.gov (United States)

    Eliot, M; Azzoni, L; Firnhaber, C; Stevens, W; Glencross, D K; Sanne, I; Montaner, L J; Foulkes, A S

    2009-01-01

    We demonstrate the application and comparative interpretations of three tree-based algorithms for the analysis of data arising from flow cytometry: classification and regression trees (CARTs), random forests (RFs), and logic regression (LR). Specifically, we consider the question of what best predicts CD4 T-cell recovery in HIV-1 infected persons starting antiretroviral therapy with CD4 count between 200 and 350 cell/muL. A comparison to a more standard contingency table analysis is provided. While contingency table analysis and RFs provide information on the importance of each potential predictor variable, CART and LR offer additional insight into the combinations of variables that together are predictive of the outcome. In all cases considered, baseline CD3-DR-CD56+CD16+ emerges as an important predictor variable, while the tree-based approaches identify additional variables as potentially informative. Application of tree-based methods to our data suggests that a combination of baseline immune activation states, with emphasis on CD8 T-cell activation, may be a better predictor than any single T-cell/innate cell subset analyzed. Taken together, we show that tree-based methods can be successfully applied to flow cytometry data to better inform and discover associations that may not emerge in the context of a univariate analysis.

  4. Tree-Based Methods for Discovery of Association between Flow Cytometry Data and Clinical Endpoints

    Directory of Open Access Journals (Sweden)

    M. Eliot

    2009-01-01

    Full Text Available We demonstrate the application and comparative interpretations of three tree-based algorithms for the analysis of data arising from flow cytometry: classification and regression trees (CARTs, random forests (RFs, and logic regression (LR. Specifically, we consider the question of what best predicts CD4 T-cell recovery in HIV-1 infected persons starting antiretroviral therapy with CD4 count between 200 and 350 cell/μL. A comparison to a more standard contingency table analysis is provided. While contingency table analysis and RFs provide information on the importance of each potential predictor variable, CART and LR offer additional insight into the combinations of variables that together are predictive of the outcome. In all cases considered, baseline CD3-DR-CD56+CD16+ emerges as an important predictor variable, while the tree-based approaches identify additional variables as potentially informative. Application of tree-based methods to our data suggests that a combination of baseline immune activation states, with emphasis on CD8 T-cell activation, may be a better predictor than any single T-cell/innate cell subset analyzed. Taken together, we show that tree-based methods can be successfully applied to flow cytometry data to better inform and discover associations that may not emerge in the context of a univariate analysis.

  5. Clinical and Experimental Study of Effects of Rhubarb on Gastrointestinal Blood Flow Perfusion in Critical Illness

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Objective: To investigate the effect of rhubarb on gastrointestinal blood perfusion in critical illness and hemorrhagic shocked rats.Methods: Clinical Study: Sixty-four septic patients, who suffered from stress ulcer, were treated with rhubarb at a dose of 25 mg/kg. Twenty-five non-septic patients were taken as control. The gastrointestinal perfusion was evaluated by intramural pH (pHi). Animal study: SD rats were anesthetized with intraperitoneal sodium pentobarbital at a dose of 20 mg/kg. Blood-letting were performed in the animals. Blood pressure reduced to 5.32 kPa and maintained for 120 mins. They were resuscitated at the end of shock by reinfusing all of the shed blood. The rats were randomly divided into four groups: Normal control, shock group, therapeutic group (shocked rats were treated with 50 mg/kg rhubarb at the end of shock) and rhubarb group (normal rats were treated with rhubarb). Laser Doppler was applied to estimate the gastrointestinal blood perfusion. Results: Clinical Study: The gastrointestinal pHi in septic patients was much lower than that in the control, whereas rhubarb could obviously elevate gastrointestinal pHi (P<0.001). In addition, rhubarb also had good effect on gastric hemorrhage caused by stress ulcer. Animal Study: Although the shocked rats were resuscitated completely, their gastrointestinal blood perfusion was much lower than that in the control. Rhubarb could significantly improve the blood perfusion in gastrointestinal mucosa and mesentery (P<0.01). Furthermore, rhubarb also increase the gastrointestinal perfusion in normal rats. Conclusion: Rhubarb could improve gastrointestinal blood perfusion in critical illness and shocked rats.

  6. High-Flow Nasal Cannula Oxygen Therapy in Adults: Physiological Benefits, Indication, Clinical Benefits, and Adverse Effects.

    Science.gov (United States)

    Nishimura, Masaji

    2016-04-01

    High-flow nasal cannula (HFNC) oxygen therapy is carried out using an air/oxygen blender, active humidifier, single heated tube, and nasal cannula. Able to deliver adequately heated and humidified medical gas at flows up to 60 L/min, it is considered to have a number of physiological advantages compared with other standard oxygen therapies, including reduced anatomical dead space, PEEP, constant F(IO2), and good humidification. Although few large randomized clinical trials have been performed, HFNC has been gaining attention as an alternative respiratory support for critically ill patients. Published data are mostly available for neonates. For critically ill adults, however, evidence is uneven because the reports cover various subjects with diverse underlying conditions, such as hypoxemic respiratory failure, exacerbation of COPD, postextubation, preintubation oxygenation, sleep apnea, acute heart failure, and conditions entailing do-not-intubate orders. Even so, across the diversity, many published reports suggest that HFNC decreases breathing frequency and work of breathing and reduces the need for respiratory support escalation. Some important issues remain to be resolved, such as definitive indications for HFNC and criteria for timing the starting and stopping of HFNC and for escalating treatment. Despite these issues, HFNC has emerged as an innovative and effective modality for early treatment of adults with respiratory failure with diverse underlying diseases. PMID:27016353

  7. A prospective clinical study of flow-mediated dilatation in burn injury.

    Science.gov (United States)

    Turk, Emin; Caliskan, Mustafa; Karagulle, Erdal; Aydogan, Cem; Oguz, Hakan; Kulaksizoglu, Sevsen; Yildirim, Erkan; Moray, Gokhan; Haberal, Mehmet

    2014-01-01

    The authors investigated endothelial function using flow-mediated dilatation (FMD) in burn patients. This study was done in burn patients with specific criteria on admission. Blood lipid profile at 1st day, high-sensitivity C-reactive protein, and FMD were assessed at 1st and 7th days, as well as at 1st and 3rd months. The highest values of high-sensitivity C-reactive protein were detected on the 7th day, which were significantly higher than those at 1st and 3rd months. The lowest value of FMD was observed on the 7th day. FMD values were higher during the 1st month compared with the 7th day. The highest value of FMD was detected in the 3rd month. It was found that FMD values measured at 7th day and 1st month were significantly lower in patients with a burn percentage of 40 or greater. Our results suggest that inflammation is more prominent on 7th day following burn. The decrease in FMD values on 7th day after injury can be attributed to endothelial damage. The increase in FMD on 3rd month after burn is attributable to effective burn treatment and gradual decrease of inflammatory mediators. The data from this study suggest that there is endothelial dysfunction and low-grade inflammation in burn patients. This condition is more prominent in patients with a burn ratio greater than 40%. Burn patients more frequently have impaired FMD, which may be indicative of arterial endothelial dysfunction and a marker for increased atherosclerosis.

  8. Correlated regions of cerebral blood flow with clinical parameters in Parkinson's disease. Comparison using 'Anatomy' and 'Talairach Daemon' software

    International Nuclear Information System (INIS)

    We assign the anatomical names of functional activation regions in the brain, based on the probabilistic cyto-architectonic atlas by Anatomy 1.7 from an analysis of correlations between regional cerebral blood flow (rCBF) and clinical parameters of the non-demented Parkinson's disease (PD) patients by statistical parametric mapping (SPM) 8. We evaluated Anatomy 1.7 of SPM toolbox compared to 'Talairach Daemon' (TD) Client 2.4.2 software. One hundred and thirty-six patients (mean age 60.0±9.09 years; 73 women and 63 men) with non-demented PD were selected. Tc-99m-HMPAO brain single-photon emission computed tomography (SPECT) scans were performed on the patients using a two-head gamma-camera. We analyzed the brain image of PD patients by SPM8 and found the anatomical names of correlated regions of rCBF perfusion with the clinical parameters using TD Client 2.4.2 and Anatomy 1.7. The SPM8 provided a correlation coefficient between clinical parameters and cerebral hypoperfusion by a simple regression method. To the clinical parameters were added age, duration of disease, education period, Hoehn and Yahr (H and Y) stage and Korean mini-mental state examination (K-MMSE) score. Age was correlated with cerebral perfusion in the Brodmann area (BA) 6 and BA 3b assigned by Anatomy 1.7 and BA 6 and pyramis in gray matter by TD Client 2.4.2 with p<0.001 uncorrected. Also, assigned significant correlated regions were found in the left and right lobules VI (Hem) with duration of disease, in left and right lobules VIIa crus I (Hem) with education, in left insula (Ig2), left and right lobules VI (Hem) with H and Y, and in BA 4a and 6 with K-MMSE score with p<0.05 uncorrected by Anatomy 1.7, respectively. Most areas of correlation were overlapped by two different anatomical labeling methods, but some correlation areas were found with different names. Age was the most significantly correlated clinical parameter with rCBF. TD Client found the exact anatomical name by the peak

  9. Clinical utility of the cryptococcal antigen lateral flow assay in a diagnostic mycology laboratory.

    Directory of Open Access Journals (Sweden)

    Brendan J McMullan

    Full Text Available BACKGROUND: Cryptococcus neoformans causes life-threatening meningitis. A recently introduced lateral flow immunoassay (LFA to detect cryptococcal antigen (CRAG is reportedly more rapid and convenient than standard latex agglutination (LA, but has not yet been evaluated in a diagnostic laboratory setting. METHODS: One hundred and six serum, 42 cerebrospinal fluid (CSF, and 20 urine samples from 92 patients with known or suspected cryptococcosis were tested by LA and LFA, and titres were compared. Results were correlated with laboratory-confirmed cryptococcosis. Serial samples were tested in nine treated patients. RESULTS: Twenty-five of 92 patients had confirmed cryptococcosis; all sera (n = 56 from these patients were positive by LFA (sensitivity 100%, 95% confidence interval (CI 93.6-100% compared with 51/56 positive by LA (sensitivity 91.1%, 95% CI 80.7-96.1%. Fifty sera from 67 patients without cryptococcosis tested negative in both assays. While LA yielded more false negative results (5/56 this did not reach statistical significance (p = 0.063. Nine CSF samples from patients with cryptococcal meningitis yielded positive results using both assays while 17/18 urine samples from patients with cryptococcosis were positive by the LFA. The LFA detected CRAG in C. gattii infection (n = 4 patients. Agreement between titres obtained by both methods (n = 38 samples was imperfect; correlation between log-transformed titres (r was 0.84. Turn-around-time was 20 minutes for the LFA and 2 h for LA. The cost per qualitative sample was 18USD and 91 USD, respectively and per quantitative sample was 38USD and 144USD, respectively. CONCLUSIONS: Qualitative agreement between the LFA and LA assays performed on serum and CSF was good but agreement between titres was imperfect. Ease of performance of the LFA and the capacity for testing urine suggest it has a role in the routine laboratory as a rapid diagnostic test or point-of-care test.

  10. Quantification of myocardial blood flow with {sup 82}Rb positron emission tomography: clinical validation with {sup 15}O-water

    Energy Technology Data Exchange (ETDEWEB)

    Prior, John O.; Allenbach, Gilles; Bischof Delaloye, Angelika [Centre Hospitalier Universitaire Vaudois and University of Lausanne, Nuclear Medicine Department, Lausanne (Switzerland); Valenta, Ines; Burger, Cyrill [Cardiac Imaging, Department of Radiology, Zurich (Switzerland); Kosinski, Marek [Centre Hospitalier Universitaire Vaudois and University of Lausanne, Nuclear Medicine Department, Lausanne (Switzerland); Centre Hospitalier Universitaire Vaudois and University of Lausanne, University Institute for Radiation Physics, Lausanne (Switzerland); Verdun, Francis R. [Centre Hospitalier Universitaire Vaudois and University of Lausanne, University Institute for Radiation Physics, Lausanne (Switzerland); Kaufmann, Philipp A. [Cardiac Imaging, Department of Radiology, Zurich (Switzerland); University of Zurich, Zurich Centre for Integrative Human Physiology (ZIHP), Zurich (Switzerland)

    2012-06-15

    coronary artery territories (p > 0.31). Quantification of MBF with {sup 82}Rb with a newly derived correction for the nonlinear extraction function was validated against MBF measured using {sup 15}O-water in control subjects and patients with mild CAD, where it was found to be accurate at high flow rates. {sup 82}Rb-derived MBF estimates seem robust for clinical research, advancing a step further towards its implementation in clinical routine. (orig.)

  11. Detection of Mycobacterium tuberculosis by Using Loop-Mediated Isothermal Amplification Combined with a Lateral Flow Dipstick in Clinical Samples

    Directory of Open Access Journals (Sweden)

    Thongchai Kaewphinit

    2013-01-01

    Full Text Available Tuberculosis (TB is a communicable disease caused by the bacterium Mycobacterium tuberculosis (MTB and is a persistent problem in the developing countries. Loop-mediated isothermal amplification (LAMP allows DNA to be amplified rapidly at a constant temperature. Here, a LAMP method was combined with a chromatographic lateral-flow dipstick (LFD to detect IS6110 gene of M. tuberculosis specifically and rapidly. The reaction was optimized at 63°C for 60 min, and the amplified DNA hybridized to an FITC-labeled oligonucleotide probe for 5 min was detected at the LFD test line 5 min after application. Excluding the step of DNA extraction, the test results could be generated approximately within 1 h. In addition to the advantage of short assay time, this technique could avoid the contact of carcinogenic ethidium bromide due to the exclusion of the electrophoresis analysis step. Furthermore, the data indicated that LAMP-LFD could detect M. tuberculosis genomic DNA as little as 5 pg. The technique showed a significant specificity since no cross-hybridization to M. intracellulare (MIC, M. fortuitum (MFT, M. avium (MAV, M. kansasii (MKS, and M. gordonae (MGD genomic DNAs was observed. In the clinical unknown samples test, the sensitivity of LAMP-LFD was 98.92 % and the specificity was 100 % compared to those of the standard culture assay. Based on its sensitivity, specificity, rapidity, low cost, and convenience, LAMP-LFD could be applicable for use in both laboratories and epidemiological surveys of MTB.

  12. Clinical application of /sup 99m/Tc-HM-PAO for cerebral blood flow imaging by SPECT. Comparison with cerebral blood flow study by PET

    Energy Technology Data Exchange (ETDEWEB)

    Inugami, Atsushi; Uemura, Kazuo; Shishido, Fumio; Tomura, Noriaki; Higano, Shuichi; Fujita, Hideaki; Kanno, Iwao

    1988-02-01

    Recently, a new tracer for cerebral blood flow (CBF) study; /sup 99m/Tc-labelled-hexamethyl-propyleneamine-oxime (/sup 99m/Tc-HM-PAO) was developed by Amersham international institute. In this paper, we reported the initial experience of tomographic CBF imaging with /sup 99m/Tc-HM-PAO in the comparison of CBF study using positron CT (PET) and 0 approx. 15 labelled CO/sub 2/. Thirty-nine patients with cerebro-vascular disease were examined mainly in the acute phase. All the subjects showed verious disturbances of CBF, which corresponded well to the PET study. However, the image-contrast with /sup 99m/Tc-HM-PAO were inferior to those of the PET study. /sup 99m/Tc-HM-PAO is considered to a good radiopharmaceutical which is readily applicable to eaven an emergency cases.

  13. Two-Dimensional Cutting (TDC Vitrectome: In Vitro Flow Assessment and Prospective Clinical Study Evaluating Core Vitrectomy Efficiency versus Standard Vitrectome

    Directory of Open Access Journals (Sweden)

    Mitrofanis Pavlidis

    2016-01-01

    Full Text Available Purpose. To evaluate comparative aspiration flow performance and also vitrectomy operating time efficiency using a double-cutting open port vitreous cutting system incorporated in a two-dimensional cutting (TDC, DORC International vitrectome design versus standard vitreous cutter. Methods. In vitro investigations compared aspiration flow rates in artificial vitreous humor at varying cutter speeds and vacuum levels using a TDC vitrectome and a standard vitrectome across different aspiration pump systems. A prospective single-centre clinical study evaluated duration of core vitrectomy in 80 patients with macular pucker undergoing 25-gauge or 27-gauge vitrectomy using either a TDC vitrectome at 16,000 cuts per minute (cpm or standard single-cut vitrectome, combined with a Valve Timing intelligence (VTi pump system (EVA, DORC International. Results. Aspiration flow rates remained constant independent of TDC vitrectome cut rate, while flow rates decreased linearly at higher cutter speeds using a classic single-blade vitrectome. Mean duration of core vitrectomy surgeries using a TDC vitreous cutter system was significantly (p<0.001 shorter than the mean duration of core vitrectomy procedures using a single-cut vitrectome of the same diameter (reduction range, 34%–50%. Conclusion. Vitrectomy surgery performed using a TDC vitrectome was faster than core vitrectomy utilizing a standard single-action vitrectome at similar cut speeds.

  14. Two-Dimensional Cutting (TDC) Vitrectome: In Vitro Flow Assessment and Prospective Clinical Study Evaluating Core Vitrectomy Efficiency versus Standard Vitrectome.

    Science.gov (United States)

    Pavlidis, Mitrofanis

    2016-01-01

    Purpose. To evaluate comparative aspiration flow performance and also vitrectomy operating time efficiency using a double-cutting open port vitreous cutting system incorporated in a two-dimensional cutting (TDC, DORC International) vitrectome design versus standard vitreous cutter. Methods. In vitro investigations compared aspiration flow rates in artificial vitreous humor at varying cutter speeds and vacuum levels using a TDC vitrectome and a standard vitrectome across different aspiration pump systems. A prospective single-centre clinical study evaluated duration of core vitrectomy in 80 patients with macular pucker undergoing 25-gauge or 27-gauge vitrectomy using either a TDC vitrectome at 16,000 cuts per minute (cpm) or standard single-cut vitrectome, combined with a Valve Timing intelligence (VTi) pump system (EVA, DORC International). Results. Aspiration flow rates remained constant independent of TDC vitrectome cut rate, while flow rates decreased linearly at higher cutter speeds using a classic single-blade vitrectome. Mean duration of core vitrectomy surgeries using a TDC vitreous cutter system was significantly (p vitrectomy procedures using a single-cut vitrectome of the same diameter (reduction range, 34%-50%). Conclusion. Vitrectomy surgery performed using a TDC vitrectome was faster than core vitrectomy utilizing a standard single-action vitrectome at similar cut speeds. PMID:27190635

  15. Progress and Clinical Application of PET Cerebral Blood Flow Measurement Method%PET脑血流量测量方法和临床应用进展

    Institute of Scientific and Technical Information of China (English)

    徐浩; 赵周社; 李红; 凌雪英; 唐勇进; 弓健; 郭斌

    2015-01-01

    Cerebral blood flow measurement for cerebrovascular disease,brain tumor diagnosis and therapeutic effect evaluation has important clinical value.PET is based on positron tracer technique for noninvasive,accurate measurement of cerebral blood flow is increasingly widely used in clinical.PET measurement of cerebral blood flow in accordance with the methods and use of positron tracer is different,and the measurement methods are divided into equilibrium method,autoradiographic method and dynamic method.15O-H2O tracer PET measurement of cerebral blood flow is considered to be the "gold standard" method of cerebral blood flow measurement.As the PET equipment resolution improving,the new image reconstruction method using PET and MRI image fusion technology continues to mature,the 18F-FDG first pass image using derivative arterial input function (IDAIF) replace artery blood sample accurate measurement of cerebral blood volume method has been paid attention to,may gradually replace the high cost of 15O-H2O measurement of cerebral blood flow.PET is noninvasive,convenient and accurate measurement of cerebral blood flow in clinical use will greatly promote cerebral vascular disease,brain tumor and brain degenerative disease early diagnosis,differential diagnosis and personalized medicine.This paper introduced PET cerebral blood flow measurement principle,methods and progress in clinical application.%脑血流量测量对于脑血管疾病、脑肿瘤诊断和疗效评估具有重要的临床价值.PET是基于正电子示剂技术无创性、精确测量脑血流量的方法,正日益广泛地应用于临床.按照PET测量脑血流量的方法和使用的正电子示踪剂不同,其测量方法分为平衡法、放射自显影法和动力学方法三种.18O-H2O示踪剂PET测量脑血流量被认为测量脑血流方法的“金标准”.随着PET设备分辨率提高、新的图像重建方法使用和PET与MRI图像融合技术不断成熟,18F-FDG首次通过、采用图

  16. Stereologic, histopathologic, flow cytometric, and clinical parameters in the prognostic evaluation of 74 patients with intraoral squamous cell carcinomas

    DEFF Research Database (Denmark)

    Bundgaard, T; Sørensen, Flemming Brandt; Gaihede, M;

    1992-01-01

    BACKGROUND AND METHODS: A consecutive series of all 78 incident cases of intraoral squamous cell carcinoma occurring during a 2-year period in a population of 1.4 million inhabitants were evaluated by histologic score (the modified classification of Jacobsson et al.), flow cytometry, stereology, ...

  17. Change and clinical significance of cerebral blood flow after concussion of brain detected with three-dimensional transcranial Doppler

    Institute of Scientific and Technical Information of China (English)

    肖兴义; 薛关生; 许国珍; 尹晓梅

    2003-01-01

    @@ From April 1995 to October 1999, 135 patients with concussion of brain were examined with threedimensional transcranial Doppler (3D-TCD) and the change of cerebral blood flow in various phases was analyzed to evaluate the effect of 3D-TCD on diagnosis and therapy of brain concussion.

  18. Comparison of the myocardial blood flow response to regadenoson and dipyridamole: a quantitative analysis in patients referred for clinical {sup 82}Rb myocardial perfusion PET

    Energy Technology Data Exchange (ETDEWEB)

    Goudarzi, Behnaz; Fukushima, Kenji; Bravo, Paco; Merrill, Jennifer [Johns Hopkins University, Division of Nuclear Medicine, Russell H Morgan Department of Radiology, Baltimore, MD (United States); Bengel, Frank M. [Johns Hopkins University, Division of Nuclear Medicine, Russell H Morgan Department of Radiology, Baltimore, MD (United States); Hannover Medical School, Department of Nuclear Medicine, Hannover (Germany)

    2011-10-15

    Regadenoson is a novel selective A{sub 2A} adenosine receptor agonist, which is administered as an intravenous bolus at a fixed dose. It is currently not clear if the absolute flow increase in response to this fixed dose is a function of distribution volume in individual patients or if it is generally comparable to the previous standard agents dipyridamole or adenosine, which are dosed based on weight. We used quantitative analysis of clinical {sup 82}Rb PET/CT studies to obtain further insights. A total of 104 subjects with normal clinical rest/stress {sup 82}Rb perfusion PET/CT were included in a retrospective analysis. To rule out confounding factors, none had evidence of prior cardiac disease, ischaemia or infarction, cardiomyopathy, diabetes with insulin use, calcium score >400, renal disease or other significant systemic disease. A group of 52 patients stressed with regadenoson were compared with a group of 52 patients stressed with dipyridamole before regadenoson became available. The groups were matched for clinical characteristics, risk factors and baseline haemodynamics. Myocardial blood flow (MBF) and myocardial flow reserve (MFR) were quantified using a previously validated retention model, after resampling of dynamic studies from list-mode {sup 82}Rb datasets. At rest, heart rate, blood pressure and MBF were comparable between the groups. Regadenoson resulted in a significantly higher heart rate (34 {+-} 14 vs. 23 {+-} 10 beats per minute increase from baseline; p < 0.01) and rate-pressure product. Patients in the regadenoson group reported less severe symptoms and required less aminophylline. Stress MBF and MFR were not different between the groups (2.2 {+-} 0.6 vs. 2.1 {+-} 0.6 ml/min/g, p = 0.39, and 2.9 {+-} 0.8 vs. 2.8 {+-} 0.7, p = 0.31, respectively). In the regadenoson group, there was no correlation between stress flow or MFR and body weight or BMI. Despite its administration at a fixed dose, regadenoson results in an absolute increase in MBF

  19. High Plasma Levels of Neuropeptide Y Correlate With Good Clinical Outcome But are not Correlated to Cerebral Blood Flow or Vasospasm After Subarachnoid Hemorrhage

    DEFF Research Database (Denmark)

    Rasmussen, Rune; Stavngaard, Trine; Jessing, Iben R;

    2016-01-01

    BACKGROUND AND PURPOSE: Delayed cerebral ischemia (DCI) is a serious and frequent complication following subarachnoid hemorrhage. Treatments with convincing effect are lacking and the pathophysiology behind DCI remains poorly understood. Neuropeptide Y (NPY) is a potent endogenous vasoconstrictor...... and a role of NPY in the development of DCI has been proposed. This study investigated the relationship between plasma-NPY and cerebral blood flow (CBF), cerebral vasospasm, DCI, and clinical outcome. METHODS: In 90 patients with subarachnoid hemorrhage, NPY was measured in peripheral blood days 2 to 11. Any...... occurrence of DCI was recorded and CBF was quantified day 3 and day 8 using computed tomography (CT) perfusion. CT angiography was performed day 8. Clinical outcome was assessed after 3 months. RESULTS: No correlation was found between plasma-NPY and CBF or angiographic vasospasm. The correlation between...

  20. Direct observations of flow path evolution during reactive transport in porous media using clinical nuclear imaging tomography

    Science.gov (United States)

    Druhan, J. L.; Finsterle, S.; Vandehey, N. T.; Boutchko, R.; O'Neil, J.; Moses, W. W.; Nico, P. S.

    2012-12-01

    Changes in the physical structure of a porous medium associated with heterogeneous reactivity are extremely difficult to observe directly. We require the ability to monitor, quantify and predict these changes in order to optimize contaminant sequestration and remediation strategies, develop carbon storage methods and preserve groundwater resources. Field-scale detection of chemically induced permeability alteration is often accomplished by multiple hydrogeophysical observations and pumping tests, whereas direct analysis of the structural changes in a porous medium are limited to small sample sizes that do not capture the range of length scales describing heterogeneity. Here we present a novel application of medical imaging techniques to directly observe variations in flow field structure associated with mineral precipitation in real time. We use a Single Photon Emission Computed Tomography (SPECT) scanner to observe the movement of a conservative 99mTc-DTPA tracer introduced to a through-flowing column of packed sediment recovered from the Old Rifle aquifer in Western Colorado. Nine individual imaging studies were carried out over the course of 112 days of continuous flow in the 30 cm long, 10 cm diameter column. During this time, organic carbon was supplied to the influent, leading to microbially mediated reduction of Fe(III) (hyrdo)oxides and sulfate. Permeability reduction associated with this reactivity is known to occur as a result of biomass accumulation and precipitation of FeS and carbonate minerals. The nine imaging datasets each yielded intensity values over a 24 hour period at a resolution of 4.42 mm3. These images were corrected for decay and attenuation to produce 4D datasets directly proportional to Tc-DTPA concentration. These data provide a highly accurate observation of the flow field during each imaging study, and are used to assign property values to the elements of a geostatistical model using the iTOUGH2 code. Permeability distributions

  1. Clinical Effectiveness of Centrifugal Pump to Produce Pulsatile Flow During Cardiopulmonary Bypass in Patients Undergoing Cardiac Surgery

    NARCIS (Netherlands)

    Gu, Y. John; van Oeveren, Willem; Mungroop, Hubert E.; Epema, Anne H.; den Hamer, Inez J.; Keizer, Jorrit J.; Leuvenink, Ron P.; Mariani, Massimo A.; Rakhorst, Gerhard

    2011-01-01

    Although the centrifugal pump has been widely used as a nonpulsatile pump for cardiopulmonary bypass (CPB), little is known about its performance as a pulsatile pump for CPB, especially on its efficacy in producing hemodynamic energy and its clinical effectiveness. We performed a study to evaluate w

  2. Use of Caval Subtraction 2D Phase-Contrast MR Imaging to Measure Total Liver and Hepatic Arterial Blood Flow: Preclinical Validation and Initial Clinical Translation.

    Science.gov (United States)

    Chouhan, Manil D; Mookerjee, Rajeshwar P; Bainbridge, Alan; Walker-Samuel, Simon; Davies, Nathan; Halligan, Steve; Lythgoe, Mark F; Taylor, Stuart A

    2016-09-01

    Purpose To validate caval subtraction two-dimensional (2D) phase-contrast magnetic resonance (MR) imaging measurements of total liver blood flow (TLBF) and hepatic arterial fraction in an animal model and evaluate consistency and reproducibility in humans. Materials and Methods Approval from the institutional ethical committee for animal care and research ethics was obtained. Fifteen Sprague-Dawley rats underwent 2D phase-contrast MR imaging of the portal vein (PV) and infrahepatic and suprahepatic inferior vena cava (IVC). TLBF and hepatic arterial flow were estimated by subtracting infrahepatic from suprahepatic IVC flow and PV flow from estimated TLBF, respectively. Direct PV transit-time ultrasonography (US) and fluorescent microsphere measurements of hepatic arterial fraction were the standards of reference. Thereafter, consistency of caval subtraction phase-contrast MR imaging-derived TLBF and hepatic arterial flow was assessed in 13 volunteers (mean age, 28.3 years ± 1.4) against directly measured phase-contrast MR imaging PV and proper hepatic arterial inflow; reproducibility was measured after 7 days. Bland-Altman analysis of agreement and coefficient of variation comparisons were undertaken. Results There was good agreement between PV flow measured with phase-contrast MR imaging and that measured with transit-time US (mean difference, -3.5 mL/min/100 g; 95% limits of agreement [LOA], ±61.3 mL/min/100 g). Hepatic arterial fraction obtained with caval subtraction agreed well with those with fluorescent microspheres (mean difference, 4.2%; 95% LOA, ±20.5%). Good consistency was demonstrated between TLBF in humans measured with caval subtraction and direct inflow phase-contrast MR imaging (mean difference, -1.3 mL/min/100 g; 95% LOA, ±23.1 mL/min/100 g). TLBF reproducibility at 7 days was similar between the two methods (95% LOA, ±31.6 mL/min/100 g vs ±29.6 mL/min/100 g). Conclusion Caval subtraction phase-contrast MR imaging is a simple and clinically

  3. Evaluation of laser Doppler flowmetry for measuring coronary band and laminar microcirculatory blood flow in clinically normal horses.

    Science.gov (United States)

    Adair, H S; Goble, D O; Shires, G M; Sanders, W L

    1994-04-01

    Once daily for 3 days, laser Doppler flowmetry was used in 5 healthy, nonsedated adult horses to evaluate coronary band and laminar microcirculatory blood flow (MBF) in both forelimbs. The coronary band had significantly (P measurement period in any one site. Significant (P laminar MBF. On occlusion of the digital arteries at the level of the fetlock, marked decrease in coronary band and laminar MBF was observed. Twenty minutes after IV administration of acetylpromazine, marked increase in coronary band and laminar MBF was observed. The technique was easily performed in standing nonsedated horses, did not inflict discomfort, lacked complications, and measurements were repeatable. This technique provides an index of digital MBF, either intermittently or continuously, avoiding introduction of invasive variables associated with other techniques.

  4. [A new objective clinical method in the evaluation of the status of blood flow in conjunctival vessels].

    Science.gov (United States)

    Polunin, G S; Pirogova, E P; Iarovaia, L D

    1989-01-01

    The suggested method for assessment of the blood aggregation characteristics in the conjunctival vessels is based on microdensitometry of the blood stream microphotographs. The method permits a graphic recording of the blood stream. The potentialities of the developed technique have been studied in comparison of the blood aggregation in patients with diabetic retinopathy and in normal subjects. The data evidence an increased coagulation activity of the blood in patients with diabetes mellitus vs. normal subjects, this correlating with the biochemical findings in examinations of these patients' hemostasis. The clinical method for assessment of the blood aggregation characteristics may be useful for the prognosis of the course of various diseases and for monitoring the treatment efficacy.

  5. Differential Effects of Acetylcholinesterase Inhibitors on Clinical Responses and Cerebral Blood Flow Changes in Patients with Alzheimer's Disease: A 12-Month, Randomized, and Open-Label Trial

    Directory of Open Access Journals (Sweden)

    Soichiro Shimizu

    2015-04-01

    Full Text Available Background/Aims: The present study evaluated the differences in treatment outcomes and brain perfusion changes among 3 types of acetylcholinesterase inhibitors (AchEIs, i.e. donepezil, rivastigmine, and galantamine. Methods: This was a prospective, longitudinal, randomized, open-label, 3-arm (donepezil, rivastigmine, or galantamine, parallel-group, 12-month clinical trial carried out in 55 patients with AD. Results: At 6 months, the results of the Mini-Mental State Examination (MMSE and the Trail Making Test (TMT-Part A showed an improvement versus baseline in the donepezil treatment group. All groups showed a significant increase in regional cerebral blood flow (rCBF, mainly in the frontal lobe. Significant rCBF reduction was observed in the temporal lobe and cingulate gyrus in all 3 groups. Conclusion: AchEI treatment prevents the progression of cognitive impairment and increases the relative rCBF in the frontal lobe.

  6. A simplified method of xenon-enhanced CT for regional cerebral blood flow (rCBF) measurement with reference to clinical experiences

    International Nuclear Information System (INIS)

    We introduced a simplified method of xenon-enhanced CT (SXe-CT) for obtaining the topographic regional cerebral blood flow (rCBF) map. In the SXe-CT, we used the method of brief (three to four minutes) inhalation of 40 % xenon. To shorten the period of xenon inhalation, we substituted a predetermined brain-blood partition coefficient (L) in the entire brain for the directly estimated L to calculate the rCBF value. Because of its non-invasiveness and simplicity, the SXe-CT can be applied to the patients with diseases in the central nervous system (CNS) without any difficulties. During the past three years, we performed the SXe-CT on 150 occasions in 100 subjects, including those with moyamoya disease, other ischemic cerebrovascular diseases, arteriovenous malformations and normal pressure hydrocephalus. In this paper, the rCBF values of seven normal healthy adults with a mean age of 24 years are reported and the flow maps of some cases of CNS diseases are presented. The normal mean value of the hemispheres was 53, those of the gray matter were in the range of 38 to 72, those of the white matter were in the range of 26 to 35 and those of the basal ganglia and thalamus were 55 to 88 (values are given in ml/100 g/min). The SXe-CT has potential advantages in obtaining clinically useful rCBF measurements. (author)

  7. Flow cytometric enumeration of CD34+ hematopoietic stem and progenitor cells in leukapheresis product and bone marrow for clinical transplantation: a comparison of three methods.

    Directory of Open Access Journals (Sweden)

    E Kraszewska

    2006-04-01

    Full Text Available Flow cytometric enumeration of CD34+ hematopoietic stem and progenitor cells (HSCs is widely used for evaluation of graft adequacy of peripheral blood and bone marrow stem cell grafts. In the present study, we review and compare the major counting techniques of stem and progenitor cells. The methods are: the Milan/Mullhouse protocol, two-platform ISHAGE (International Society of Hematotherapy and Graft Engineering and single-platform ISHAGE analysis system. According to the Milan/Mulhouse protocol, HSCs are identified by CD34 antibody staining and easy gating strategy. The ISHAGE guidelines for detection of CD34+ cells are based on a four-parameter flow cytometry method (CD34PE/CD45PerCP staining, side and forward angle light scatter thus employing multiparameter gating strategy. With two-platform ISHAGE protocol, an absolute CD34+ count is generated by incorporating the leukocyte count from an automated hematology analyser. The single-platform ISHAGE method to determine the absolute CD34+ count directly from a flow cytometer includes the use of Trucount tubes (Becton Dickinson with a known number of fluorescent beads. CD34+ cells were quantified in mobilized peripheral blood, collected by leukapheresis, and bone marrow from 42 samples from patients with hematological malignancies. The differences against the means display low disagreement between the Milan/Mulhouse and ISHAGE protocols, with discrepancies of up to 2.5% (two-platform ISHAGE--2.6% (single-platform ISHAGE in enumeration of CD34+ cells in leukapheresis product and 4.8% (two-platform ISHAGE--4.9% (single-platform ISHAGE in bone marrow. Our results show high correlation among all three methods. Since the three protocols are compatible, choosing the most convenient in terms of costs, simplicity and compliance with clinical results appears to be a logical consequence.

  8. Cerebral blood flow measurement in patients with impaired consciousness: usefulness of {sup 99m}Tc-HMPAO single-photon emission tomography in clinical practice

    Energy Technology Data Exchange (ETDEWEB)

    Chang Chia-Cheng; Kuwana, Nobumasa; Noji, Masato; Tanabe, Yutaka; Koike, Y. [Department of Neurosurgery, Yokohama Minami Kyosai Hospital, Yokohama (Japan); Ikegami, Tadashi [Department of Radiology, Yokohama Minami Kyosai Hospital, Yokohama (Japan)

    1998-09-01

    The relationship between impairment of consciousness and quantitative cerebral blood flow (CBF) was investigated. The mean CBF of the whole brain was measured by the Patlak-plot method using technetium-99m hexamethylpropylene amine oxime single-photon emission tomography ({sup 99m}Tc-HMPAO SPET) in patients with the following diseases: cerebral infarction, intraparenchymal haemorrhage, subarachnoid haemorrhage, brain tumour and cerebral contusion. The clinical symptoms were evaluated according to the severity of impaired consciousness, aphasia and dementia. Four hundred and eighty-five CBF measurements were performed. Patients with alert consciousness showed an age-related decline in mean CBF. Patients with aphasia showed a significant reduction in mean CBF compared with those without aphasia. Impaired consciousness was proportional to reduction in mean CBF regardless of types of pathology, and the size of lesion did not influence the mean CBF. Patients with dementia showed a significant reduction in mean CBF proportional to the severity of dementia. The quantitative measurement of CBF using {sup 99m}Tc-HMPAO SPET is reliable in clinical evaluations. (orig.) With 3 tabs., 10 refs.

  9. A novel lateral flow assay based on GoldMag nanoparticles and its clinical applications for genotyping of MTHFR C677T polymorphisms

    Science.gov (United States)

    Hui, Wenli; Zhang, Sinong; Zhang, Chao; Wan, Yinsheng; Zhu, Juanli; Zhao, Gang; Wu, Songdi; Xi, Dujuan; Zhang, Qinlu; Li, Ningning; Cui, Yali

    2016-02-01

    Current techniques for single nucleotide polymorphism (SNP) detection require tedious experimental procedures and expensive and sophisticated instruments. In this study, a visual genotyping method has been successfully established via combining ARMS-PCR with gold magnetic nanoparticle (GoldMag)-based lateral flow assay (LFA) and applied to the genotyping of methylenetetrahydrofolate reductase (MTHFR) C677T. C677T substitution of the gene MTHFR leads to an increased risk of diseases. The genotyping result is easily achievable by visual observation within 5 minutes after loading of the PCR products onto the LFA device. The system is able to accurately assess a broad detection range of initial starting genomic DNA amounts from 5 ng to 1200 ng per test sample. The limit of detection reaches 5 ng. Furthermore, our PCR-LFA system was applied to clinical trials for screening 1721 individuals for the C677T genotypes. The concordance rate of the genotyping results detected by PCR-LFA was up to 99.6% when compared with the sequencing results. Collectively, our PCR-LFA has been proven to be rapid, accurate, sensitive, and inexpensive. This new method is highly applicable for C677T SNP screening in laboratories and clinical practices. More promisingly, it could also be extended to the detection of SNPs of other genes.

  10. H9N2亚型禽流感病毒荧光定量PCR方法的建立及初步应用%DEVELOPMENT AND APPLICATION OF QUATITATIVE FLUORESCENT PCR ASSAY FOR DETECTION OF H9N2 SUBTYPE AVIAN INFLUENZA VIRUS

    Institute of Scientific and Technical Information of China (English)

    胡涛; 滕巧泱; 申伟霞; 张月娥; 李国新; 李雪松; 闫丽萍; 姜秀云; 李泽君

    2013-01-01

    viruses, 1000-fold higher than conventional PCR. The variability of inter-plates and intra-plates were less than 5%and 1%, respectively. Then, qPCR was used to detect oropharyngeal swab samples. As a result, qPCR was 100-fold more sensitive than conventional PCR in testing clinical samples. Therefore, qPCR method was highly specific, accurate, reproducible and sensitive and thus could be used for diagnosis of H9N2 AIV.

  11. Evaluation of quatitative scintigraphic method in diagnosis of esophagic involvement of Progressive Systemic Sclerosis

    International Nuclear Information System (INIS)

    Twenty patients with Progressive Systemic Sclerosis are studied by scintigraphic methodology. The esophageal transit method is used for liquid and solid meals. The results are compared with the ones of a control group, without or not gastrintestinal problems but without autoimmune diasese. 99 sup(m)Tc-sulfurcolloid is used as labelling compound. The studies were done in supine and orthostatical position. (M.A.C.)

  12. Study Of Topical Anti-Inflammatory Potency And Clinical Efficacy Of Formulations Of Mometasone And Betamethasone By Cutaneous Blood Flow Measurements In Psoriatic Patients Using Laser Doppler Velocimetry

    Directory of Open Access Journals (Sweden)

    Mulekar S. V

    1997-01-01

    Full Text Available Laser Doppier Velocimetry (LDV was used to measure cutaneous blood flow (CBF in psoriatic skin lesions to assess the effect of once daily application of Mometasone furoate (MF in a base claimed to possess a “reservoir” effect, as against Betamethasone-17-valarate (BV in a conventional cream base, applied twice daily, for 4 weeks. Bilaterally symmetrical active lesions were studied in 10 psoriatics, at baseline and at the end of 2 and 4 weeks’ treatment. The formulations were also evaluated for topical anti-inflammatory potency in terms of their ability to inhibit the Post-Ischaemic-Reactive-Hyperaemic-Response (PIRHR induced on normal uninvolved skin treated under occlusion. The lesions were also assessed subjectively for clinical Psoriatic Hyperaemia Index (PHI = CBF on lesions/CBF on uninvolved skin: 8.42 + 1.74 & 10.13 + 1.70 correlating with high CPI (9 + 0.50 & 9.1 + 0.51. During treatment with MF or BV, the lesions resolved rapidly, with a concomitant decrease in PHI and CPI (Week 2 : PHI = 3.40 + 0.46 & 5.19 + 1.65, CPI = 4.15 + 0.86& 5.20 + 0.87 and Week 4 : PHI = 1.99 + 0.23 & 2.81 + 0.74 CPI = 2.00 + 0.50 & 2.88 + 0.72 respectively. The two formulations Inhibited PIRHR to same extent (auc/min: Control = 1871 + 399.22, MF = 536.11 + 153.34 & BV = 567.5 + 110.76, indicating equal potency. The results show that pharmaceutical factor such as vehicle can significantly influence the clinical efficacy of corticoids.

  13. Comparative evaluation of Roche Aurora FLOW, Becton and Dickinson Viper system, and Dynex DS2 for detection of Chlamydia trachomatis, Neisseria gonorrhoeae, and Trichomonas vaginalis in various clinical specimens.

    Science.gov (United States)

    Vahidnia, Ali; Costa, Sandra; Veenings, Sanne; Tuin, Hellen; van Loon, Linda; Bliekendaal, Harry

    2014-11-01

    The purpose of this study is to introduce a high-throughput system, Aurora FLOW, for the simultaneous detection of 3 clinically relevant pathogens of sexually transmitted infections. Comparative evaluation with other systems revealed an overall concordance of 97.9% for Chlamydia trachomatis and comparable performance for Neisseria gonorrhoeae and Trichomonas vaginalis.

  14. Regional cerebral blood flow and its correlation with clinical assessment in senile dementia of Alzheimer type and multi-infarct dementia

    International Nuclear Information System (INIS)

    Twenty-one patients with senile dementia of Alzheimer type (SDAT), 11 patients with multi-infarct dementia (MID), and 6 healthy volunteers were examined by SPECT using Xe-inhalation method. These patients also underwent an intelligence test according to the Gottfries-Brane-Steen (GBS) scale. Patients with mild SDAT did not have a significantly decreased regional cerebral blood flow (rCBF). In moderate or severe cases, however, a significantly decreased rCBF was bilaterally observed in all regions, except for the basal ganglia. This was marked in the temporoparietal region. A group of moderate or severe MID patients had a significantly decreased rCBF especially in the basal ganglia. It was also observed in the temporoparietal region, but not in the frontal region. Among the SDAT patients, there was a good correlation between rCBF and GBS scale in all the regions, except for the basal ganglia. In the case of MID patients, correlations were observed both between rCBF in the left side of the brain and clinical findings according to the method of Hasegawa and between rCBF in the right side of the frontal region and the motor function on the GBS scale. These findings may have implications for the different pathophysiology between SDAT and MID. (N.K.)

  15. Flow: Statistics, visualization and informatics for flow cytometry

    Directory of Open Access Journals (Sweden)

    Kepler Thomas B

    2008-06-01

    Full Text Available Abstract Flow is an open source software application for clinical and experimental researchers to perform exploratory data analysis, clustering and annotation of flow cytometric data. Flow is an extensible system that offers the ease of use commonly found in commercial flow cytometry software packages and the statistical power of academic packages like the R BioConductor project.

  16. Flow: Statistics, visualization and informatics for flow cytometry

    OpenAIRE

    Kepler Thomas B; Frelinger Jacob; Chan Cliburn

    2008-01-01

    Abstract Flow is an open source software application for clinical and experimental researchers to perform exploratory data analysis, clustering and annotation of flow cytometric data. Flow is an extensible system that offers the ease of use commonly found in commercial flow cytometry software packages and the statistical power of academic packages like the R BioConductor project.

  17. CLINICAL ANALYSIS AND OPTIMIZATION OF POST-REMISSION THERAPY FOR ACUTE MYELOID LEUKEMIA PATIENTS WITH MINIMAL RESIDUAL DISEASE AS DETERMINED BY FLOW CYTOMETRY

    Directory of Open Access Journals (Sweden)

    Hayato Maruoka

    2010-05-01

    Full Text Available

    Background: Although several prognostic indicators of de novo acute myeloid leukemia (AML patients have been identified, the clinical significance of minimal residual disease (MRD needs to be evaluated further in Japanese adult patients.

    Methods: Using three color flow cytometry, we identified leukemia-associated phenotypes (LAP in bone marrow specimens at diagnosis and assessed the relationship between clinical outcomes and the presence of marrow MRD in 33 patients who achieved a morphologic complete remission (CR and were followed after CR.

    Results: Of 33 consecutive patients, we detected MRD in 20 patients after achieving CR (Group A and did not in 13 patients (Group B, with 2-year overall survival (OS rates of 49.0% and 84.6%, respectively (P =.0317, and relapse-free survival (RFS rates of 13.7% and 91.7%, respectively (P=.0010. By multivariate analysis, MRD-positivity at post-induction was found to be associated with a shorter duration of RFS (P=.0042. Notably, we achieved MRD negativity in

  18. Two-Dimensional Cutting (TDC) Vitrectome: In Vitro Flow Assessment and Prospective Clinical Study Evaluating Core Vitrectomy Efficiency versus Standard Vitrectome

    OpenAIRE

    Mitrofanis Pavlidis

    2016-01-01

    Purpose. To evaluate comparative aspiration flow performance and also vitrectomy operating time efficiency using a double-cutting open port vitreous cutting system incorporated in a two-dimensional cutting (TDC, DORC International) vitrectome design versus standard vitreous cutter. Methods. In vitro investigations compared aspiration flow rates in artificial vitreous humor at varying cutter speeds and vacuum levels using a TDC vitrectome and a standard vitrectome across different aspiration p...

  19. COMPARISON OF FLOW AND VOLUME ORIENTED INCENTIVE SPIROMETRY ON LUNG FUNCTION AND DIAPHRAGM MOVEMENT AFTER LAPAROSCOPIC ABDOMINAL SURGERY: A RANDOMIZED CLINICAL PILOT TRIAL

    OpenAIRE

    Gopala Krishna Alaparthi; Alfred Joseph Augustine *; Anand R; Ajith Mahale

    2013-01-01

    Objective:This study was designed to evaluate the efficacy of two types of incentive spirometer (flow andvolume) on pulmonary function and diaphragm excursion in patients who underwent laparoscopic surgery.Materials and Methods:Twenty sample sizes with eleven men and nine women who underwent laparoscopicsurgery were randomly divided as follows: 10 subjects performed flow oriented incentive spirometer group,and other 10 subjects performed volume oriented incentive spirometer group. (Other ther...

  20. Flow Rounding

    OpenAIRE

    Kang, Donggu; Payor, James

    2015-01-01

    We consider flow rounding: finding an integral flow from a fractional flow. Costed flow rounding asks that we find an integral flow with no worse cost. Randomized flow rounding requires we randomly find an integral flow such that the expected flow along each edge matches the fractional flow. Both problems are reduced to cycle canceling, for which we develop an $O(m \\log(n^2/m))$ algorithm.

  1. An evaluation of the regional cerebral blood flow (rCBF) measurement by xenon-enhanced dynamic CT with helical scanning technique and the functional imaging by multiplanar reconstruction (MPR). Fundamental study and clinical application

    International Nuclear Information System (INIS)

    We evaluated the quantitative rCBF by xenon-enhanced dynamic CT with helical scanning technique on all brain regions, and also examined clinical usefulness of coronal and sagittal section images which are similar to SPECT images obtained by the functional multiplanar reconstitution (MPR) imaging of many successive flow maps. We used 14 clinical cases. The conventional xenon-enhanced CT was simple and ideal method to measure rCBF, however, it had disadvantages; it gives a few laminagraphical images or only the axial directional images, compared to SPECT or PET. There is a risk to overlook lesions out of the image or not to obtain the whole images of the lesion. Although the helical scanning technique has a methodological characteristics to use adjacent data for the image reconstitution, it is by no means inferior to the conventional method in the contrast resolution or the image resolution when the co-helical function and an appropriate reconstituted function were used. It has an advantage to scan all brain regions by only one cycle of scanning. Furthermore on making good use of the property that the helical scanning technique can give the successive data, we can observe rCBF by coronal and sagittal images when many flow maps were made up by reconstituted images of the narrow steps. This shows the clinical usefulness of this technique. One of the future problem to be solved is to decrease the exposure dose. (K.H.)

  2. Immunophenotypic Characterization and Quantification of Neoplastic Bone Marrow Plasma Cells by Multiparametric Flow Cytometry and Its Clinical Significance in Korean Myeloma Patients

    OpenAIRE

    Cho, Young-Uk; Park, Chan-Jeoung; Park, Seo-Jin; Chi, Hyun-Sook; Jang, Seongsoo; Park, Sang Hyuk; Seo, Eul-Ju; Yoon, Dok Hyun; Lee, Jung-Hee; Suh, Cheolwon

    2013-01-01

    Multiparametric flow cytometry (MFC) allows discrimination between normal and neoplastic plasma cells (NeoPCs) within the bone marrow plasma cell (BMPC) compartment. This study sought to characterize immunophenotypes and quantitate the proportion of NeoPCs in BMPCs to diagnose plasma cell myeoma (PCM) and evaluate the prognostic impact of this method. We analyzed the MFC data of the bone marrow aspirates of 76 patients with PCM and 33 patients with reactive plasmacytosis. MFC analysis was per...

  3. [Development of software for the verification of patient flow through a daily clinical environment by use of the radiology information system (RIS)].

    Science.gov (United States)

    Nose, Hideo; Shiraishi, Junji

    2012-01-01

    In order to manage relationship between patients' movements and operating efficiency, we developed a special software which can make patient flow visible on a display monitor by use of actual data obtained from the radiology information system (RIS). In this software, a simple floor map of the radiology department in our hospital was drawn on the monitor and each patient was indicated with a small figure. This software was developed with commercialized computer software [Excel 2007 visual basic applications (VBA) Microsoft]. Movements of the patient figures were simulated by use of actual time data such as registration of radiology department, and start and ending time of examinations. The patient figures were moved along with predetermined flow lines every second. The movements of the patient figures were controlled by several buttons (i.e., play and stop) and setting switches for determining reproduction date and time. In conclusion, by use of this software, the patient flows could be analyzed systematically by checking efficient operation such as average waiting time of the patients and/or standby time of radiological technologists. PMID:23089836

  4. Clinical Implications of Having Reduced Mid Forced Expiratory Flow Rates (FEF25-75), Independently of FEV1, in Adult Patients with Asthma

    OpenAIRE

    Riley, Craig M.; Sally E. Wenzel; Castro, Mario; Erzurum, Serpil C.; Chung, Kian Fan; Fitzpatrick, Anne M.; Gaston, Benjamin; Israel, Elliot; Moore, Wendy C.; Bleecker, Eugene R.; Calhoun, William J.; Jarjour, Nizar N.; Busse, William W.; Peters, Stephen P.; Teague, W. Gerald

    2015-01-01

    Introduction FEF25-75 is one of the standard results provided in spirometry reports; however, in adult asthmatics there is limited information on how this physiological measure relates to clinical or biological outcomes independently of the FEV1 or the FEV1/FVC ratio. Purpose To determine the association between Hankinson’s percent-predicted FEF25-75 (FEF25-75%) levels with changes in healthcare utilization, respiratory symptom frequency, and biomarkers of distal airway inflammation. Methods ...

  5. Clinical and Experimental Research into Treatment of Hysteromyoma with Promoting Qi Flow and Blood Circulation,Softening and Resolving Hard Lump

    Institute of Scientific and Technical Information of China (English)

    桑海莉; 吴葆卿

    2004-01-01

    One hundred and twenty cases of hysteromyoma were treated with Kangfu Xiaozheng Tablet (康妇消症treatment group had a shrinking hysteromyoma and the improvement of symptoms such as irregular menstruation, pain in the waist and abdomen and so on. The total effective rate of 95.83% obtained in the treatment group was obviously higher than 82.00% in the control group (P<0.01). With the effect of eliminating symptoms, anti-coagulation, anti-inflammation and stopping pain, Kangfu Xiaozheng Tablet has been found to be a safe drug without toxicity in acute toxicology and clinical observation.

  6. Clinical usefulness of positron emission tomography in the evaluation of regional cerebral blood flow and cerebral oxygen metabolism under glycerol and carbon dioxide loadings

    Energy Technology Data Exchange (ETDEWEB)

    Tanada, Shuji; Yonekura, Yoshiharu; Senda, Michio

    1987-02-01

    Cerebral blood flow (CBF) and oxygen metabolism (CMRO/sub 2/) were studied in normal cerebral cortices by positron emission tomography using continuous inhalation method of oxygen-15 labeled carbon dioxide and oxygen, and single inhalation method of oxygen-15 labeled carbon monoxide. The values of CBF, CMRO/sub 2/, and oxygen extraction fraction (OEF) in cerebral cortices of 18 healthy normal volunteers represented 40 +- 7 ml/100 ml/min, 3.2 +- 0.5 ml O/sub 2//100 ml/min, and 0.43 +- 0.07, respectively. In cases with glycerol loading, CBF increased in 10/14 cases. Studies of 6 cases with intracranial pressure indicated the presence of mechanism by which depressed CMRO/sub 2/ improved and was kept in normal values. The loading of 5% carbon dioxide showed an increase in CBF in cases with cerebral infarction, which implied the good cerebral vascular response to the elevated arterial carbon dioxide, but no particular changes were observed in CMRO/sub 2/ which seemed to be less responsive to the elevated arterial carbon dioxide level. In cases with moyamoya disease, 5% carbon dioxide loading showed no changes in CBF and CMRO/sub 2/. This suggested the poor cerebral vascular response to the elevation of arterial carbon dioxide, while X-ray CT failed to demonstrate any abnormalities in corresponding areas. Positron emission tomography proved to have a great potentiality regarding the evaluation of the changes in cerebral blood flow and cerebral oxygen metabolism under various loadings.

  7. Diagnostic Performance of a New Rapid Lateral Flow Immunoassay in Patients Suspected of Heparin-Induced Thrombocytopenia and Its Clinical Consequences.

    Science.gov (United States)

    Berroëta, Clarisse; Crespin, Malvina; Bouabdallah, Kamel; Pargade, Sophie; Huchet, François-Xavier; Bourel, Patrick; Philip, Ivan; Lebuisson, Agathe

    2016-02-01

    We prospectively evaluated the diagnostic accuracy of a new rapid assay (STic Expert HIT) alone or in combination with a clinical score in 90 HIT-suspected patients. The 4Ts score was calculated, and ELISA and serotonin-release assay (SRA) were performed; the average time taken for test results were 2 and 5 days for ELISA and SRA, respectively. The STic test was performed in our laboratory as an evaluation exercise and the result was available in 1 hour, but results were not communicated to the clinicians so as to not influence management. Diagnostic performance of STic test was assessed, alone and in combination with 4Ts score. HIT was diagnosed in 19 patients. The sensitivity, specificity, and positive and negative predictive values for the STic test alone were 95%, 92%, 75%, and 98%, respectively, with an accuracy of 92%. The likelihood ratio for positive and negative results with the STic test was 11.2 and 0.06. The combination of the 4Ts score and the STic test results had a negative predictive value of 100% and a negative likelihood ratio of 0. The favorable performance of the STic test may allow for the rapid exclusion of HIT in combination with a low to intermediate pretest clinical probability. During the subsequent year, using the STic test in real time to rapidly exclude the diagnosis, we observed a 50% reduction in danaparoid administration in HIT-suspected patients. PMID:26595149

  8. Clinical evaluation of leukocyte differential count in peripheral blood by five-color flow cytometry%五色流式细胞术分类计数外周血白细胞的临床评价

    Institute of Scientific and Technical Information of China (English)

    邢莹; 王建中; 普程伟; 尚柯

    2013-01-01

    目的 评价五色流式细胞术分类计数外周血白细胞的临床应用价值.方法 选取2010年9至12月北京大学第一医院就诊的265例患者静脉全血标本,以显微镜检查为参考方法,同时用LH750全自动血细胞分析仪和FC500流式细胞仪分类计数白细胞,统计分析显微镜、血细胞分析仪和流式细胞术分类计数外周血白细胞的相关性.选取2010年8至11月北京大学第一医院、北京市道培医院和北京军区总医院的40例患者的静脉全血标本,以显微镜检查为参考方法,同时用LH750全自动血细胞分析仪和NAVIOS流式细胞仪分类计数白细胞,统计分析显微镜、血细胞分析仪和流式细胞术分类计数外周血白细胞的相关性和流式细胞术的临床诊断效率.结果 FC500流式细胞仪采用仪器自动分析软件进行分类,与显微镜分类计数5种白细胞均具有一定相关性(均P<0.01),其中以淋巴细胞、中性粒细胞和嗜酸粒细胞的相关性最佳(r=0.955、0.928、0.876).NAVIOS 流式细胞仪采用手工输入设门策略进行分类,与显微镜方法比较除嗜碱粒细胞外均具有良好的相关性(r >0.700,均P<0.01),其中对检出中性粒细胞、淋巴细胞和原始细胞的相关性较高(r=0.950、0.915、0.852).以显微镜法分类计数外周血不成熟粒细胞1%为临界值,流式细胞术检出不成熟粒细胞的敏感度为87%,特异度为76%.以显微镜法检查外周血原始细胞0.5%为临界值,流式细胞术检出的敏感度为100%,特异度为92%.结论 应用五色流式细胞术在不同流式细胞仪上分类计数外周血白细胞与显微镜法均具有良好的相关性,对检出原始细胞和不成熟粒细胞具有较高的敏感度.%Objective To explore the clinical application values of five-color flow cytometry for leukocyte differential count in peripheral blood.Methods Leukocyte differentiation in 265 peripheral blood samples collected at

  9. Clinical outcomes of fractional flow reserve by computed tomographic angiography-guided diagnostic strategies vs. usual care in patients with suspected coronary artery disease: the prospective longitudinal trial of FFRCT: outcome and resource impacts study

    Science.gov (United States)

    Douglas, Pamela S.; Pontone, Gianluca; Hlatky, Mark A.; Patel, Manesh R.; Norgaard, Bjarne L.; Byrne, Robert A.; Curzen, Nick; Purcell, Ian; Gutberlet, Matthias; Rioufol, Gilles; Hink, Ulrich; Schuchlenz, Herwig Walter; Feuchtner, Gudrun; Gilard, Martine; Andreini, Daniele; Jensen, Jesper M.; Hadamitzky, Martin; Chiswell, Karen; Cyr, Derek; Wilk, Alan; Wang, Furong; Rogers, Campbell; De Bruyne, Bernard

    2015-01-01

    Aims In symptomatic patients with suspected coronary artery disease (CAD), computed tomographic angiography (CTA) improves patient selection for invasive coronary angiography (ICA) compared with functional testing. The impact of measuring fractional flow reserve by CTA (FFRCT) is unknown. Methods and results At 11 sites, 584 patients with new onset chest pain were prospectively assigned to receive either usual testing (n = 287) or CTA/FFRCT (n = 297). Test interpretation and care decisions were made by the clinical care team. The primary endpoint was the percentage of those with planned ICA in whom no significant obstructive CAD (no stenosis ≥50% by core laboratory quantitative analysis or invasive FFR < 0.80) was found at ICA within 90 days. Secondary endpoints including death, myocardial infarction, and unplanned revascularization were independently and blindly adjudicated. Subjects averaged 61 ± 11 years of age, 40% were female, and the mean pre-test probability of obstructive CAD was 49 ± 17%. Among those with intended ICA (FFRCT-guided = 193; usual care = 187), no obstructive CAD was found at ICA in 24 (12%) in the CTA/FFRCT arm and 137 (73%) in the usual care arm (risk difference 61%, 95% confidence interval 53–69, P< 0.0001), with similar mean cumulative radiation exposure (9.9 vs. 9.4 mSv, P = 0.20). Invasive coronary angiography was cancelled in 61% after receiving CTA/FFRCT results. Among those with intended non-invasive testing, the rates of finding no obstructive CAD at ICA were 13% (CTA/FFRCT) and 6% (usual care; P = 0.95). Clinical event rates within 90 days were low in usual care and CTA/FFRCT arms. Conclusions Computed tomographic angiography/fractional flow reserve by CTA was a feasible and safe alternative to ICA and was associated with a significantly lower rate of invasive angiography showing no obstructive CAD. PMID:26330417

  10. Semi-quantitative assessment of cerebral blood flow with {sup 99m}Tc-HMPAO SPET in type I diabetic patients with no clinical history of cerebrovascular disease

    Energy Technology Data Exchange (ETDEWEB)

    Quirce, R.; Carril, J.M.; Jimenez-Bonilla, J.F.; Amado, J.A.; Gutierrez-Mendiguchia, C.; Banzo, I.; Blanco, I.; Uriarte, I.; Montero, A. [Servicio de Medicina Nuclear, Hospital Universitario Marques de Valdecilla, Santander (Spain)

    1997-12-01

    In 65 type I diabetic patients we prospectively evaluated brain perfusion by means of single-photon emission tomography after the injection of 740- 1110 MBq of technetium-99m hexamethylpropylene amine oxime. Thirty-five of the patients presented complications secondary to their diabetes. None showed CNS symptoms. A semiquantitative analysis was performed drawing 50 symmetrical regions of interest (ROIs) per patient. The relative contribution of each ROI to the total blood flow in each slice was compared with the relative contribution of the same ROI in a control group of ten healthy volunteers. Relative values of any ROI in the study group higher or lower than the mean {+-}2 SD in respect of the same ROI in the control group were considered abnormal. The results revealed hypoperfusion in 207 ROIs in the 65 patients with diabetes mellitus: of these ROIs, 113 were frontal, 10 frontotemporal, 20 temporal, 18 parietal, 11 occipital and 35 cerebellar. A total of 137 ROIs showed hyperperfusion: 17 frontal, 3 frontotemporal, 19 temporal, 18 parietal, 19 parieto-occipital, 29 occipital and 32 cerebellar. Out of 65 type I diabetic patients, 61 showed at least one hypoperfused ROI (P = 0.0064 vs. controls) and 25 showed more than three hypoperfused ROIs. None of the control subjects showed more than three hypoperfused regions (P<0.001). The results obtained demonstrate the existence of subclinical abnormalities of brain blood perfusion in patients with type I diabetes mellitus and no history of cerebrovascular disease, thereby allowing the initiation of intensive preventive measures. (orig.) With 3 figs., 5 tabs., 33 refs.

  11. Semi-quantitative assessment of cerebral blood flow with 99mTc-HMPAO SPET in type I diabetic patients with no clinical history of cerebrovascular disease

    International Nuclear Information System (INIS)

    In 65 type I diabetic patients we prospectively evaluated brain perfusion by means of single-photon emission tomography after the injection of 740- 1110 MBq of technetium-99m hexamethylpropylene amine oxime. Thirty-five of the patients presented complications secondary to their diabetes. None showed CNS symptoms. A semiquantitative analysis was performed drawing 50 symmetrical regions of interest (ROIs) per patient. The relative contribution of each ROI to the total blood flow in each slice was compared with the relative contribution of the same ROI in a control group of ten healthy volunteers. Relative values of any ROI in the study group higher or lower than the mean ±2 SD in respect of the same ROI in the control group were considered abnormal. The results revealed hypoperfusion in 207 ROIs in the 65 patients with diabetes mellitus: of these ROIs, 113 were frontal, 10 frontotemporal, 20 temporal, 18 parietal, 11 occipital and 35 cerebellar. A total of 137 ROIs showed hyperperfusion: 17 frontal, 3 frontotemporal, 19 temporal, 18 parietal, 19 parieto-occipital, 29 occipital and 32 cerebellar. Out of 65 type I diabetic patients, 61 showed at least one hypoperfused ROI (P = 0.0064 vs. controls) and 25 showed more than three hypoperfused ROIs. None of the control subjects showed more than three hypoperfused regions (P<0.001). The results obtained demonstrate the existence of subclinical abnormalities of brain blood perfusion in patients with type I diabetes mellitus and no history of cerebrovascular disease, thereby allowing the initiation of intensive preventive measures. (orig.)

  12. Flow visualization

    CERN Document Server

    Merzkirch, Wolfgang

    1974-01-01

    Flow Visualization describes the most widely used methods for visualizing flows. Flow visualization evaluates certain properties of a flow field directly accessible to visual perception. Organized into five chapters, this book first presents the methods that create a visible flow pattern that could be investigated by visual inspection, such as simple dye and density-sensitive visualization methods. It then deals with the application of electron beams and streaming birefringence. Optical methods for compressible flows, hydraulic analogy, and high-speed photography are discussed in other cha

  13. Clinical Implications of Having Reduced Mid Forced Expiratory Flow Rates (FEF25-75, Independently of FEV1, in Adult Patients with Asthma.

    Directory of Open Access Journals (Sweden)

    Craig M Riley

    Full Text Available FEF25-75 is one of the standard results provided in spirometry reports; however, in adult asthmatics there is limited information on how this physiological measure relates to clinical or biological outcomes independently of the FEV1 or the FEV1/FVC ratio.To determine the association between Hankinson's percent-predicted FEF25-75 (FEF25-75% levels with changes in healthcare utilization, respiratory symptom frequency, and biomarkers of distal airway inflammation.In participants enrolled in the Severe Asthma Research Program 1-2, we compared outcomes across FEF25-75% quartiles. Multivariable analyses were done to avoid confounding by demographic characteristics, FEV1, and the FEV1/FVC ratio. In a sensitivity analysis, we also compared outcomes across participants with FEF25-75% below the lower limit of normal (LLN and FEV1/FVC above LLN.Subjects in the lowest FEF25-75% quartile had greater rates of healthcare utilization and higher exhaled nitric oxide and sputum eosinophils. In multivariable analysis, being in the lowest FEF25-75% quartile remained significantly associated with nocturnal symptoms (OR 3.0 [95%CI 1.3-6.9], persistent symptoms (OR 3.3 [95%CI 1-11], ICU admission for asthma (3.7 [1.3-10.8] and blood eosinophil % (0.18 [0.07, 0.29]. In the sensitivity analysis, those with FEF25-75%

  14. 彩色多普勒血流显像结合定量分析技术评价肾血流灌注的临床研究%Clinical study on renal flow perfusion using color Doppler flow imaging combined with quantitative analysis technique

    Institute of Scientific and Technical Information of China (English)

    李薇玢; 林铤; 张艳容; 吕清; 王新房; 谢明星; 项飞翔; 陈玉媛; 刘莹莹; 郭美荣

    2009-01-01

    Objective To explore the clinical value of color Doppler flow imaging(CDFI) combined with quantitative analysis technique to evaluate renal flow perflusion. Methods Twenty patients with different renal diseases matched with healthy control subjects were examined with Philips iU22 CDFI system. CDFI system and Qlab quantitative technique were used to measure renal restrictive index(RI), vascularization index(VI), flow index(FI), vascularization-flow index (VFI). The patients all received renal single-photon emission computed tomography (SPECT) examination. Results The RI of 32 kidney with lower flow perfusion in SPECT were higher than in the contol group (P <0.01). VI,FI, VFI were lower than those in control(VI, VFI, P <0.01 ;FI, P <0.05). Conelusious The renal blood flow perfusion of patients with renal diseases are lower than that of healthy people. It has high clinical value using CDFI combined with quantitative analysis technique to evaluate the renal perfusion of the patients with renal diseases.%目的 探讨彩色多普勒血流显像结合血流定量分析技术评价肾血流灌注的临床意义.方法 采用Philips iU22彩色多普勒血流显像结合血流定量分析技术分别测量20例正常对照者和20例肾疾病患者的肾叶间动脉、小叶间动脉阻力指数(RI)、血管指数(VI)、血流指数(FI)、血管-血流指数(VFI),并进行比较分析.所有肾疾病患者均于彩色多普勒显像前后进行放射性核素肾动态扫描.结果 20例肾疾病患者单光子发射计算机断层显像检查(SPECT)显示血流灌注减少的32只肾叶间动脉、小叶间动脉RI值明显高于正常对照组(P<0.01),VI、FI、VFI值均明显低于正常对照组(VI,VFI,P<0.01;FI,P<0.05).结论 肾疾病患者的肾血流灌注显著低于正常对照组,利用彩色多普勒血流显像结合血流定量分析技术可以无创性定量评价肾血流灌注.

  15. Evaluation of combined, conservative treatment impact on the clinical course, blood flow parameters and muscle perfusion in the group of patients with newly diagnosed, untreated peripheral arterial disease (PAD)

    International Nuclear Information System (INIS)

    Background: Epidemiological studies determined incidence of obliterative atherosclerosis as ranging between 2.45 -10 %. The course of disease is often asymptomatic and demonstration of symptoms occurs when vascular lesions are significantly advanced. This article discusses conservative treatment of patients with PAD whose key complaint was intermittent claudication. The Authors proposed multi-stage treatment regimen of this disease including lifestyle modification, treatment of comorbid disorders, and pharmacotherapy (aspirin, pentoxifylline, buflomedil, L-arginine). The study evaluated influence of 6-month treatment on clinical course, blood flow parameters as well as muscle perfusion. Material/Methods: The participants included 35 patients (14 women - 40.0 %, and 21 men - 60.0 %) aged from 49 to 80 (mean age 68.37 ± 10.25 years) first time in life diagnosed with PAD. Physical examination, standard vascular tests (ankle-brachial, thigh-ankle and thigh-shin indices, maximum flow velocity, PI and RI in selected arteries), perfusion scintigraphy of lower limbs muscles at rest and on exertion were carried out before and after 6 months of treatment. Results: Statistically significant increase of total walking distance (198.0 meters vs. 330.0 meters, p< 0.01) and improvement in average values of perfusion indices of all studied areas were detected at rest and after exercise. For shin perfusion index at rest (right and left) and for thigh perfusion index after exercise (right) the difference was statistically significant at p< 0.05. Conclusions: Combined medical treatment brought on positive effect on patients suffering from recently diagnosed, thus not yet treated atherosclerotic lower limb ischaemia of IIA and IIB stages according to Fontaines scale. (authors)

  16. Rotating flow

    CERN Document Server

    Childs, Peter R N

    2010-01-01

    Rotating flow is critically important across a wide range of scientific, engineering and product applications, providing design and modeling capability for diverse products such as jet engines, pumps and vacuum cleaners, as well as geophysical flows. Developed over the course of 20 years' research into rotating fluids and associated heat transfer at the University of Sussex Thermo-Fluid Mechanics Research Centre (TFMRC), Rotating Flow is an indispensable reference and resource for all those working within the gas turbine and rotating machinery industries. Traditional fluid and flow dynamics

  17. Geological flows

    CERN Document Server

    Bratkov, Yu N

    2008-01-01

    In this paper geology and planetology are considered using new conceptual basis of high-speed flow dynamics. Recent photo technics allow to see all details of a flow, 'cause the flow is static during very short time interval. On the other hand, maps and images of many planets are accessible. Identity of geological flows and high-speed gas dynamics is demonstrated. There is another time scale, and no more. All results, as far as the concept, are new and belong to the author. No formulae, pictures only.

  18. Vortical flows

    CERN Document Server

    Wu, Jie-Zhi; Zhou, Ming-De

    2015-01-01

    This book is a comprehensive and intensive book for graduate students in fluid dynamics as well as scientists, engineers and applied mathematicians. Offering a systematic introduction to the physical theory of vortical flows at graduate level, it considers the theory of vortical flows as a branch of fluid dynamics focusing on shearing process in fluid motion, measured by vorticity. It studies vortical flows according to their natural evolution stages,from being generated to dissipated. As preparation, the first three chapters of the book provide background knowledge for entering vortical flows. The rest of the book deals with vortices and vortical flows, following their natural evolution stages. Of various vortices the primary form is layer-like vortices or shear layers, and secondary but stronger form is axial vortices mainly formed by the rolling up of shear layers.  Problems are given at the end of each chapter and Appendix, some for helping understanding the basic theories, and some involving specific ap...

  19. Endovascular blood flow measurement system

    Science.gov (United States)

    Khe, A. K.; Cherevko, A. A.; Chupakhin, A. P.; Krivoshapkin, A. L.; Orlov, K. Yu

    2016-06-01

    In this paper an endovascular measurement system used for intraoperative cerebral blood flow monitoring is described. The system is based on a Volcano ComboMap Pressure and Flow System extended with analogue-to-digital converter and PC laptop. A series of measurements performed in patients with cerebrovascular pathologies allows us to introduce “velocity-pressure” and “flow rate-energy flow rate” diagrams as important characteristics of the blood flow. The measurement system presented here can be used as an additional instrument in neurosurgery for assessment and monitoring of the operation procedure. Clinical data obtained with the system are used for construction of mathematical models and patient-specific simulations. The monitoring of the blood flow parameters during endovascular interventions was approved by the Ethics Committee at the Meshalkin Novosibirsk Research Institute of Circulation Pathology and included in certain surgical protocols for pre-, intra- and postoperative examinations.

  20. Preliminary validation of direct detection of foot-and-mouth disease virus within clinical samples using reverse transcription loop-mediated isothermal amplification coupled with a simple lateral flow device for detection.

    Directory of Open Access Journals (Sweden)

    Ryan A Waters

    Full Text Available Rapid, field-based diagnostic assays are desirable tools for the control of foot-and-mouth disease (FMD. Current approaches involve either; 1 Detection of FMD virus (FMDV with immuochromatographic antigen lateral flow devices (LFD, which have relatively low analytical sensitivity, or 2 portable RT-qPCR that has high analytical sensitivity but is expensive. Loop-mediated isothermal amplification (LAMP may provide a platform upon which to develop field based assays without these drawbacks. The objective of this study was to modify an FMDV-specific reverse transcription-LAMP (RT-LAMP assay to enable detection of dual-labelled LAMP products with an LFD, and to evaluate simple sample processing protocols without nucleic acid extraction. The limit of detection of this assay was demonstrated to be equivalent to that of a laboratory based real-time RT-qPCR assay and to have a 10,000 fold higher analytical sensitivity than the FMDV-specific antigen LFD currently used in the field. Importantly, this study demonstrated that FMDV RNA could be detected from epithelial suspensions without the need for prior RNA extraction, utilising a rudimentary heat source for amplification. Once optimised, this RT-LAMP-LFD protocol was able to detect multiple serotypes from field epithelial samples, in addition to detecting FMDV in the air surrounding infected cattle, pigs and sheep, including pre-clinical detection. This study describes the development and evaluation of an assay format, which may be used as a future basis for rapid and low cost detection of FMDV. In addition it provides providing "proof of concept" for the future use of LAMP assays to tackle other challenging diagnostic scenarios encompassing veterinary and human health.

  1. 流式细胞术检测HLA-B27及其临床意义%Detection of HLA-B27 by flow cytometry and it's clinical evaluation

    Institute of Scientific and Technical Information of China (English)

    金明威; 陈哲; 陈颖

    2011-01-01

    Objective: To study the clinical evaluation of HLA -B27 detection by flow cytometry (FCM) for diagnosing ankylostomiasis.Methods: 41 patients with AS, 62 patients with lumbago and 112 normal people were analyzed by FCM.Results: HLA -B27 were positive in 38 (92.6% ); among 41 patients with AS, 6 (9.67% ) of 62 patients with lumbago and 2 ( 1.78% ) of 112 normal persons.Conclusions: The positive rate of HLA - B27 in patients with AS is obviously higher than that of other groups.The detection of HLA - B27 by FCM can play an important role in diagnosing AS.%目的 通过流式细胞术检测外周血白细胞HLA-B27的表达,并探讨其时强直性脊柱炎(AS)的诊断价值.方法 利用流式细胞仪(FCM)检测41例AS患者、62例背痛及腰腿痛患者及112例健康体检者的外周血HLA-B27表达.结果 41例AS患者中,HLA阳性38例(92.6%);62例背痛腰腿痛患者中,HLA-B27阳性6例(9.67%);112例健康人群中,HLA-B27阳性2例(1.78%).结论 AS患者HLA-B27阳性率明显增高,HLA-B27检测可视为临床支持AS诊断的重要依据.

  2. Retirement Flows

    OpenAIRE

    Alan L. Gustman; Thomas L. Steinmeier

    1983-01-01

    This paper considers labor market flows of older workers among the states of nonretirement, partial retirement and full retirement.Statistics are presented which describe entry, exit and continuation rates for each state by age, duration dependence, and "reverse flows."One important finding which has implications for the structure of utility functions embedded in life cycle retirement models is the relatively high incidence but short duration of partial retirement.These implications are discu...

  3. CLINICAL BIOCHEMISTRY

    Science.gov (United States)

    Assessment of the health status of animals through measurement of cellular, biochemical, and macromolecular constituents in blood, secretions, and excretions has been variously referred to as clinical chemistry, clinical biochemistry, or clinical pathology. he genesis of this dis...

  4. Flow assurance

    Energy Technology Data Exchange (ETDEWEB)

    Mullins, O.C.; Dong, C. [Schlumberger-Doll Research Center, Cambridge, MA (United States); Elshahawi, H. [Shell Exploration and Production Company, The Hague (Netherlands)

    2008-07-01

    This study emphasized the need for considering flow assurance for producing oil and gas, particularly in high cost areas such as deepwater. Phase behaviour studies, sticking propensities, and interfacial interactions have been investigated in many laboratory studies using asphaltenes, wax, hydrates, organic and inorganic scale, and even diamondoids. However, the spatial variation of reservoir fluids has received little attention, despite the fact that it is one of the most important factors affecting flow assurance. This issue was difficult to address in a systematic way in the past because of cost constraints. Today, reservoir fluid variation and flow assurance can be considered at the outset of a project given the technological advances in downhole fluid analysis. This study described the origins of reservoir fluid compositional variations and the controversies surrounding them. It also described the indispensable chemical analytical technology. The impact of these reservoir fluid compositional variations on flow assurance considerations was also discussed. A methodology that accounts for these variations at the outset in flow assurance evaluation was also presented.

  5. Vortical flows

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Jie-Zhi [Peking Univ., Beijing (China). College of Engineering; Ma, Hui-Yang [Univ. of Chinese Academy of Sciences, Beijing (China). Dept. of Physics; Zhou, Ming-De [Arizona Univ., Tucson, AZ (United States). Dept. of Aerospace and Mechanical Engineering

    2015-11-01

    This book is a comprehensive and intensive book for graduate students in fluid dynamics as well as scientists, engineers and applied mathematicians. Offering a systematic introduction to the physical theory of vortical flows at graduate level, it considers the theory of vortical flows as a branch of fluid dynamics focusing on shearing process in fluid motion, measured by vorticity. It studies vortical flows according to their natural evolution stages,from being generated to dissipated. As preparation, the first three chapters of the book provide background knowledge for entering vortical flows. The rest of the book deals with vortices and vortical flows, following their natural evolution stages. Of various vortices the primary form is layer-like vortices or shear layers, and secondary but stronger form is axial vortices mainly formed by the rolling up of shear layers. Problems are given at the end of each chapter and Appendix, some for helping understanding the basic theories, and some involving specific applications; but the emphasis of both is always on physical thinking.

  6. Granular flow

    DEFF Research Database (Denmark)

    Mitarai, Namiko; Nakanishi, Hiizu

    2012-01-01

    Granular material is a collection of macroscopic particles that are visible with naked eyes. The non-equilibrium nature of the granular materials makes their rheology quite different from that of molecular systems. In this minireview, we present the unique features of granular materials focusing ...... the shear flow of dry granular materials and granule-liquid mixture....

  7. Clinical biophysics

    Energy Technology Data Exchange (ETDEWEB)

    Anbar, M.; Spangler, R.A.; Scott, P.

    1985-01-01

    Chapters are included on clinical decision making, principles of biomedical engineering, computers and their medical uses, clinical radiobiology, diagnostic x-ray radiology, clinical applications of ultrasonics, nuclear medicine, NMR imaging, diagnostic imaging, bioelectric techniques in diagnosis and therapy, biophysical aspects of the clinical laboratory, and biophysical aspects of modern surgery.

  8. A Curvature Flow Unifying Symplectic Curvature Flow And Pluriclosed Flow

    OpenAIRE

    DAI, SONG

    2013-01-01

    Streets and Tian introduced pluriclosed flow and symplectic curvature flow in recent years. Here we construct a curvature flow to unify these two flows. We show the short time existence of our flow and exhibit an obstruction to long time existence.

  9. Hydrodynamics, flow, and flow fluctuations

    International Nuclear Information System (INIS)

    The matter formed in heavy-ion collisions has been shown to interact so strongly that it behaves like a relativistic fluid during its expansion. I show that initial-state fluctuations, due to the nucleonic structure of incoming nuclei, have a large effect of flow observables. I argue that these fluctuations do not reduce to eccentricity fluctuations. (author)

  10. Prognostic value of fractional flow reserve

    DEFF Research Database (Denmark)

    Johnson, Nils P; Tóth, Gábor G; Lai, Dejian;

    2014-01-01

    BACKGROUND: Fractional flow reserve (FFR) has become an established tool for guiding treatment, but its graded relationship to clinical outcomes as modulated by medical therapy versus revascularization remains unclear. OBJECTIVES: The study hypothesized that FFR displays a continuous relationship...

  11. Media Flow

    DEFF Research Database (Denmark)

    Kabel, Lars

    2015-01-01

    News and other kinds of journalistic stories, 16-17 hours a day, all year round, on all platforms, also the moderated social media. The key research thesis behind this article is that the continuous and speedy stream of news stories and media content now is becoming the centre of the production...... processes and the value creation in converged multimedia newsrooms. The article identify new methods and discuss editorial challenges in handling media flow....

  12. 咀嚼对脑血流动力学影响的临床实验研究%Clinical experimental study on the effects of mastication on the dynamics of cerebral blood flow

    Institute of Scientific and Technical Information of China (English)

    魏洁; 陈树国; 徐璟; 郭长军; 袁硕

    2011-01-01

    目的 观察正常(铪)受试者咀嚼运动前后脑血流的改变,探讨咀嚼对脑血流动力学的影响及意义.方法 应用经颅彩色多谱勒超声扫描仪(transcranial color doppler,TCCD),探测30名正常(胎)受试者在安静状态下和咀嚼无糖口香糖10分钟后脑血流速的改变,对大脑中动脉收缩期峰流速(systolic peak flow velocity,Vs)、舒张期末峰流速(enddiastolic peak flow velocity,Vd)、平均峰流速(mean peak flow velocity,Vm)进行统计分析.结果 ①30名受试者咀嚼前脑血流速值均数(单位:cm/s):收缩期峰流速(Vs)-91.785,舒张期末峰流速(Vd)-39.385,平均峰流速(Vm)-55.735;咀嚼后均数:收缩期峰流速(Vs)-103.030,舒张期末峰流速(Vd)-46.015,平均峰流速(Vm)-64.090;②经两样本均数f检验可知咀嚼前后的大脑中动脉的收缩期峰流速(Vs)、舒张期末峰流速(Vd)、平均峰流速(Vm)的结果在男性与女性之间均无显著性差异(P>0.05);③受试者咀嚼前后配对t检验结果显示,受试者咀嚼后大脑中动脉收缩期峰流速(Vs)、舒张期末峰流速(Vd)及平均峰流速(Vm)与咀嚼前相比均有显著性差异(P<o.05).结论 咀嚼可使大脑中动脉血管充盈度增加,血流速度显著加快.%Objective To observe the cerebral blood flow changes of normal occlusion subjects before and after the movement of chewing, and to investigate the effects and significance of chewing on cerebral blood flow dynamics. Methods Transcranial Color Doppler (TCCD) was used to detect the changes of cerebral blood flow in 30 normal occlusion subjects in a quiet state and 10 minutes after chewing sugarless gum, and the systolic peak flow velocity (Vs), enddiastolic peak flow velocity (Vd), mean peak flow velocity (Vm) were all statistically analyzed. Results (Dthe mean value of cerebral blood flow of 30 subjects before chewing (unit: cm/s): systolic peak flow velocity (Vs) -91.785, enddiastolic peak flow velocity (Vd) -39.385, and

  13. 流式细胞术检测急性髓细胞白血病微小残留病的临床价值%Clinical Value of Flow Cytometry for Minimal Residual Disease of Acute Myeloid Leukemia

    Institute of Scientific and Technical Information of China (English)

    何正梅; 陶善东; 邓媛; 于亮

    2014-01-01

    Objective To explore the clinical value of flow cytometry for minimal residual disease of acute myeloid leu -kemia.Methods 66 cases of patients with AML ’ s myeloid antigen positive expression were detected by FCM .Results The positive expression rate of myeloid antigen in patients with AML was (19.98 ±11.98)%,and the highest positive expression rate were M2 subtype and medullary system antigen MPO;At the end of the induction chemotherapy ,46 cases had remission ,and 20 cases had no remission.The positive expression rate of myeloid antigen in the remission group was (10.50 ±10.49)%,and the positive expression rate in the non-remission group was (16.80 ±17.39)%.The highest positive expression was MPO .The posi-tive expression rate of medullary system total antigen in the remission group and the non-remission group were higher than that of the control group(P<0.05);The positive expression rate of medullary system total antigen in the remission group were lower than that of the non-remission group(P<0.05).Conclusion Detection of 9 kinds of myeloid antibodies for the patients with AML has good effect ,and it can provide reliable basis for chemotherapy regimens and therapeutic effect .%目的:探讨流式细胞术检测急性髓细胞白血病微小残留病的临床价值。方法采用FCM检测66例初治AML患者诱导化疗前后各亚型髓系抗原阳性表达情况。结果初诊时66例AML患者髓系抗原阳性总表达率为(19.98±11.98)%,M2亚型和髓系抗原MPO阳性表达率最高;诱导化疗结束时46例缓解、20例未缓解。髓系抗原缓解组阳性总表达率为(10.50±10.49)%,未缓解组阳性总表达率为(16.80±17.39)%,2组MPO阳性表达率最高。缓解组与未缓解组患者髓系抗原总阳性表达率均显著高于对照组,差异具有统计学意义(P<0.05);缓解组患者髓系抗原总阳性表达率显著低于未缓解组,差异具有统计学意义(P<0.05

  14. Clinical Trials

    Science.gov (United States)

    Clinical trials are research studies that test how well new medical approaches work in people. Each study answers ... prevent, screen for, diagnose, or treat a disease. Clinical trials may also compare a new treatment to a ...

  15. Continental Lower-crustal Flow: Channel Flow and Laminar Flow

    Science.gov (United States)

    LI, Dewei

    Numerous geological, geophysical and geochemical investigations and finite element modeling indicate that crustal flow layers exist in the continental crust. Both channel flow model and laminar flow model have been created to explain the flow laws and flow mechanisms. As revealed by the channel flow model, a low-viscosity channel in middle to lower crust in orogen or plateau with thick crust and high elevation would flow outward from mountain root in response to lateral pressure gradient resulted from topographic loading or to denudation. However, according to the laminar flow model proposed based on investigation of the Qinghai-Tibet plateau, circulative movement of crustal lithologies with different rheological properties between basin and orogen would occur, under the driving forces resulted from dehydration and melting of subduction plate on active continental margin and from thermal energy related to upwelling and diapiring of intercontinental mantle plume or its gravitational interactions. Similarly, when driven by gravity, the softened or melted substances of the lower crust in a basin would flow laterally toward adjacent mountain root, which would result in a thinned basin crust and a thickened orogenic crust. Partially melted magma within the thickened orogenic lower crust would cause vertical movement of metamorphic rocks of lower to middle crust due to density inversion, and the vertical main stress induced by thermal underplating of lower crust would in turn lead to formation of metamorphic core complexes and low-angle detachment fault systems. Lateral spreading of uplifting mountain due to gravitation potential would result in thrust fault systems on the border between mountain and basin. Meanwhile, detritus produced synchronously by intense erosion of uplifting mountain would be transported and deposited along the marginal deep depression in the foreland basin dragged by lower crust flow. Channel flow is similar to laminar flow in a variety of aspects

  16. Flow and Flow Decay of Refractory Castables

    Institute of Scientific and Technical Information of China (English)

    CHEN Zhiqiang; Bjom Myhre; Bjorn Sandberg

    2003-01-01

    Installation of refractoty castables depend not only on flow, but also on how soon the flow is lost because of setting. The loss of flow (flow decay) has always been one of the main problems of refractory castable manufacturers,a problem that has not been too well described in literature. The flow decay has been studied for a castable system based on alumina, pointing out some general trends. The flow decay was found very temperature sensitive, being strongly accelerated by termperature increases. To compensate for excessive flow loss, a retarder like citric acid may be used. Thus flow decay was measured as a function of citric acid (retarder) addition at 35 ℃ .

  17. Clinical Research and Clinical Trials

    Science.gov (United States)

    ... Meetings, Conferences & Events Partnering & Donating to the NICHD Staff Directory ... Clinical Research Skip sharing on social media links Share this: Page Content Clinical research is research that directly involves a ...

  18. Xenon computed tomographic blood flow mapping

    International Nuclear Information System (INIS)

    Xenon CT flow information appears to be clinically useful in the diagnosis and management of a broad spectrum of clinical disorders. It also appears to be a useful tool for the experimental study of the cerebral circulation, with recent work also extending to application to the study of solid abdominal organs. The authors therefore found xenon CT CBF mapping to be a useful new blood flow methodology and are of the opinion that as CT technology improves, one will be able to obtain still better flow information with less accompanying radiation exposure and/or a reduction in the level of xenon inhalation required

  19. CLINICAL OBSERVATION ABOUT THE EFFECT OF BLOOD-LETTING OF JING-POINTS ON CEREBRAL BLOOD FLOW IN STROKE PATIENTS AT THE EARLY STAGE AND EXPERIMENTAL STUDY ON ITS MECHANISMS IN THE RABBIT

    Institute of Scientific and Technical Information of China (English)

    WANG Xiuyun; REN Shusheng; GUO Yi; ZHOU Guoping; ZHOU Zhiliang; PAN Rongqing; XU Tangping; LI Qing; WANG Xin; REN Huanzhong

    2002-01-01

    In this paper,the authors sum their research resuits about the effect of blood-letting of Jing(Well)-point on cerebral blood flow both in stroke patients and in experimental cerebral ischemia,cerebral hematoma and hypertension rabbits.In 30cases of stroke (cerebral hemorrhage and cerebral infarction)patients,blood flow state of the anterior cerebral artery(ACA),middle cerebral artery(MCA)and the posterior cerebral artery (PCA), and the blood flow velocity of the bilateral vertebral artery (VA)and the basil artery(BA)are determined before and afterpricking blood of the Twelve Jing-points.In experimental cerebral ischernia (by occlusion of the common carotid ertery) rabbits ,cerebral hematoma model rabbits and intravenous injection of noradrenaline induced hypertension rabbits, rheoencephalogram(REC) is detected before and after blood letting of the twelve"Jing -points.In these 30stroke patients,ultrasound Doppler examination's results show that in 22 cases (73.33%) whose blood flow velocity decreases,after blood-letting of the 12 Jing-points, it ncreases significantly(P< 0.01); in the rest 8 cases (26.67%) whose blood flow velocity speeds up,after treatment,it decreases evidently(P<tly (P< 0.01), showing a good dual-directional regulative effect of blood -letting therapy.In experimental cerebral ischemia rabbits,cerebral hematoma rabbits and hypertension rabbits whose REG lowers in the amplitude apparently ( P < 0.01 ), after blood letting stimulation of the 12 Jing-points, it increases at different degrees.Three patterns of stimulation as blood letting stimulation, pain stimulation and Jing-point stimulation, also the 3factors of blood-letting,may contribute to their effect on improvement of the cerebral blood flow.Somatic affterent nerve,sympathetic nerve of the vasular wall,central cholinergic nerve(M receptors)and adrenergic nerve (α receptors) participate in the effect of blood letting on cerebral blood flow.

  20. Environment Flow Assessment with Flow Regime Transition

    Science.gov (United States)

    Su, J.; Ho, C. C.; Chang, L. C.

    2015-12-01

    To avoid worsen river and estuarine ecosystems cause by overusing water resources, environmental flows conservation is applied to reduce the impact of river environment. Environmental flows refer to water provided within a river, wetland or coastal zone to sustain ecosystems and benefits to human wellbeing. Environment flow assessment is now widely accepted that a naturally variable flow regime, rather than just a minimum low flow. In this study, we propose four methods, experience method, Tenant method, hydraulic method and habitat method to assess the environmental flow of base flow, flush flow and overbank flow with different discharge, frequency and occurrence period. Dahan River has been chosen as a case to demonstrate the assessment mechanism. The alternatives impact analysis of environment and human water used provides a reference for stakeholders when holding an environmental flow consultative meeting.

  1. 多普勒超声探测胎儿肝静脉血流频谱及其临床意义%Duplex Doppler ultrasonography of fetal hepatic venous flow and its clinical significance

    Institute of Scientific and Technical Information of China (English)

    吴细香; 胡翔宇; 焦彤; 柴云生; 林永熙

    2000-01-01

    Objective To study the Doppler flow spectrum of fetal hepatic vein.Methods One hundred and twelve pregnant women of gestational age 27~42 weeks were examined by common ultrasonography,then the vein of fetal liver were investigated by two dimensional and duplex Doppler ultrasonography.Results The Doppler flow spectrum of normal fetal hepatic vein could be classified into 3 types:Type Ⅰ,68 cases,showed two negative waveforms.Type Ⅱ,23 cases showed 3-phase wavefoml,two negative and one transient positive waves,in accordance with those of adult.Type Ⅲ,21 cases,showed one negative waveform.Of all the spectra,two cases were abnormal,showing markedly increased positive flow,which Was proved to be due to congenital heart disease.Conclusions Investigaring the fetal hepatic venous flow by duplex Doppler ultrosongraphy was feasible.The Doppler flow spectrum showed that the increase in the frequence and amplitude of positive flow spectrum could be important to the diagnosis of the congenital heart disease.%目的 探讨胎儿肝静脉的多普勒血流频谱及其临床意义.方法 112例孕妇(孕龄27~42周)行常规超声检查后,对胎儿肝中静脉再行二维超声及多普勒超声检查.结果 正常胎儿肝静脉多普勒血流频谱分为三型.Ⅰ型68例,表现为二个负向波,占60.7%.Ⅱ型23例,表现为三相波即二个负向波一个短暂正向波,与正常成人一致,占21,6%.Ⅲ型21例,表现为一个负向波,占18.7%.2例胎儿肝静脉血流频谱出现异常,其正向血流明显增高,经尸检证实为先心病.结论 多普勒超声探测胎儿肝静脉血流频谱是完全可行的,其正向血流增高增多可为临床诊断胎儿某些先心病提供重要依据.

  2. Phase Flow Rate Measurements of Annual Flows

    OpenAIRE

    Al-Yarubi, O.S.; Lucas, Gary

    2009-01-01

    The Annular flow regime makes measurement of the total liquid flow rate difficult. It is even more difficult to measure the individual flow rate of either the oil or the water. In a vertical Perspex tube (i.d. = 50 mm) using a newly-designed flow loop in the University of Huddersfield, annular flow was established and different measurements were carried out. One possible on-line measurement technique to achieve the oil volume fraction measurement is an automated bypass...

  3. Teaching Phagocytosis Using Flow Cytometry

    Directory of Open Access Journals (Sweden)

    John Boothby

    2009-12-01

    Full Text Available Investigative microbiology on protists in a basic teaching laboratory environment is limited by student skill level, ease of microbial culture and manipulation, instrumentation, and time. The flow cytometer is gaining use as a mainstream instrument in research and clinical laboratories, but has had minimal application in teaching laboratories. Although the cost of a flow cytometer is currently prohibitive for many microbiology teaching environments and the number of trained instructors and teaching materials is limited, in many ways the flow cytometer is an ideal instrument for teaching basic microbiology. We report here on a laboratory module to study phagocytosis in Tetrahymena sp. using flow cytometry in a basic microbiology teaching laboratory. Students and instructors found the flow cytometry data analysis program, Paint-A-GatePRO-TM, to be very intuitive and easy to learn within a short period of time. Assessment of student learning about Tetrahymena sp., phagocytosis, flow cytometry, and investigative microbiology using an inquiry-based format demonstrated an overall positive response from students.

  4. Clinical value of the placental abruption diagnosed by color Doppler ultrasonic combining with enhancement Doppler E-flow imaging%彩色多普勒超声结合增强型能量多普勒成像诊断胎盘早剥的临床价值探讨

    Institute of Scientific and Technical Information of China (English)

    魏达友; 梁玉婷; 蔡永秋; 巫朝君; 刘思怡; 吴绍锋

    2008-01-01

    目的 探讨彩色多普勒超声结合增强型能量多普勒(E-Flow)成像诊断胎盘早剥,尤其是轻型胎盘早剥的声像图特点,为临床提供有效的诊断依据.方法 应用彩色多普勒超声结合E-Flow对50例重型胎盘早剥、23例轻型胎盘早剥的声像图及临床结局进行分析研究.结果 50例重型胎盘早剥的彩色多普勒超声结合E-Flow的诊断与临床及产后病理诊断相符,诊断符合率100%;23例轻型胎盘早剥的彩色多普勒超声结合E-Flow的诊断与临床及产后病理诊断符合19例,诊断符合率83%,漏诊、误诊4例(17%).73例胎盘早剥患者中剖宫产60例,阴道分娩13例.结论 增强型能量多普勒超声结合彩色多普勒超声成像技术对重型胎盘早剥的诊断准确率高,为轻型胎盘早剥的诊断提供了新手段,并能动态监测轻型胎盘早剥的转归.%Objective To explore the ultrasonographical characteristics of placental abruption, especially the light placental abruption that was diagnosed by color Doppler ultrasonic combining with enhancement Doppler E-flow imaging, providing diagnosis data for clinical treatment. Methods With color Doppler ultrasonic and enhancement Doppler E-flow imaging, an analysis was made on the ultrasonography and clinical result of 50 patients with heavy placental abruption and 23 patients with light placental abruption. Results The diagnosis and clinical treatment of 50 patients with heavy placental abruption who had been diagnosed by color Doppler ultrasonic combining with enhancement Doppler E-flow imaging were in conformity with the postnatal pathological diagnosis. The coincidence rate in diagnosis was 100%. Of 23 patients with light placental abruption who had been diagnosed by color Doppler ultrasonic combining with enhancement E-flow Doppler imaging, 19 cases' diagnosis and clinical treatment were in accordance with their postnatal pathological diagnosis and the coincidence rate was 83%, 4 cases were

  5. The Cause and Effect Correlation Analysis between Body weight & Blood Flows and Adequacy of Hemodialysis with Clinic Condition of Chronic Maintenance Hemodialysis Patients%血液透析患者体重和血流量与透析充分性的因果关系分析

    Institute of Scientific and Technical Information of China (English)

    门雯瑾; 丁致民

    2011-01-01

    通过测定维持性血液透析患者的体重和在线血流量、采用在线尿素清除率监测(on-line clearance monitoring,OCM)法测Kt/V值及单室尿素动力模型DaugirdasⅡ公式计算Kt/V值的两种方法,探讨患者体重和血流量与透析充分性之间的因果关系.结论为两种方法测得的血液透析患者的体重和血流量均与Kt/V密切相关,彼此之间存在因果关系,较低的体重,较高的血流量是保证透析充分性的重要指标.%To understand the cause and effect correlation analysis between body weight & blood flow and adequacy of hemo-dialysis with clinic condition of chronic maintenance hemodialysis patients. The body weight & blood flow of the chronic maintenance hemodialysis patients is a valuable reference for the hemodialysis quality. There is a cause and effect correlation between the body weight & blood flows and adequacy of dialysis

  6. The Study of Emergency Patient Flow Forecast Model Based on Patient Clinical Behavior Data Warehouse%基于临床行为数据的急诊病人流向预测模型与应用研究

    Institute of Scientific and Technical Information of China (English)

    郑西川; 孙宇; 陈霆; 吴允真

    2016-01-01

    Objective: To analyze and predict the flow direction of hospital emergency patients and provide guidance for the treatment of patients, and to achieve the deployment of medical resources by means of information technology. Methods: Based on the Hadoop parallel computing platform, construct the data warehouse of the patients, and use big data mining analysis technology to analyze the behavior of the patients and the direction of the flow. Results: Combined with hospital emergency information construction, the introduction of Hospital Internet applications, emergency flow analysis and prediction model can provide the emergency population to provide advice, and provide data for emergency management. Conclusion: The big data era of hospital emergency management needs to be fine management, patient flow analysis and prediction model can help the hospital to allocate medical resources, improve the emergency medical environment.%目的:利用病人就诊行为数据,分析预测医院急诊病人流向,为病人就诊提供导引,通过信息技术手段实现医疗资源调配。方法:基于Hadoop并行计算平台,构建患者就诊诊疗数据仓库,利用大数据挖掘分析技术,对患者就诊行为属性与就诊流向进行多维度关联分析,建立急诊流向分析与预测模型。结果:结合医院急诊信息化建设,引入医院互联网应用,急诊流向分析与预测模型能为患者提供急诊人群提供建议,并为急诊管理提供数据依据。结论:大数据时代医院急诊管理需要进行精细化管理,病人流向分析与预测模型能帮助医院调配医疗资源,改善急诊医疗环境。

  7. Effect of TIPS placement on portal and splanchnic arterial blood flow in 4-dimensional flow MRI

    Energy Technology Data Exchange (ETDEWEB)

    Stankovic, Zoran [Northwestern University, Department of Radiology, Feinberg School of Medicine, Chicago, IL (United States); University Medical Center Freiburg, Department of Diagnostic Radiology and Medical Physics, Freiburg (Germany); Roessle, Martin; Schultheiss, Michael [University Medical Center Freiburg, Department of Gastroenterology, Freiburg (Germany); Euringer, Wulf; Langer, Mathias [University Medical Center Freiburg, Department of Diagnostic Radiology and Medical Physics, Freiburg (Germany); Salem, Riad; Barker, Alex; Carr, James; Collins, Jeremy D. [Northwestern University, Department of Radiology, Feinberg School of Medicine, Chicago, IL (United States); Markl, Michael [Northwestern University, Department of Radiology, Feinberg School of Medicine, Chicago, IL (United States); Northwestern University, Department of Biomedical Engineering, McCormick School of Engineering, Chicago, IL (United States)

    2015-09-15

    To assess changes in portal and splanchnic arterial haemodynamics in patients undergoing transjugular intrahepatic portosystemic shunt (TIPS) using four-dimensional (4D) flow MRI, a non-invasive, non-contrast imaging technique. Eleven patients undergoing TIPS implantation were enrolled. K-t GRAPPA accelerated non-contrast 4D flow MRI of the liver vasculature was applied with acceleration factor R = 5 at 3Tesla. Flow analysis included three-dimensional (3D) blood flow visualization using time-resolved 3D particle traces and semi-quantitative flow pattern grading. Quantitative evaluation entailed peak velocities and net flows throughout the arterial and portal venous (PV) systems. MRI measurements were taken within 24 h before and 4 weeks after TIPS placement. Three-dimensional flow visualization with 4D flow MRI revealed good image quality with minor limitations in PV flow. Quantitative analysis revealed a significant increase in PV flow (562 ± 373 ml/min before vs. 1831 ± 965 ml/min after TIPS), in the hepatic artery (176 ± 132 ml/min vs. 354 ± 140 ml/min) and combined flow in splenic and superior mesenteric arteries (770 ml/min vs. 1064 ml/min). Shunt-flow assessment demonstrated stenoses in two patients confirmed and treated at TIPS revision. Four-dimensional flow MRI might have the potential to give new information about the effect of TIPS placement on hepatic perfusion. It may explain some unexpected findings in clinical observation studies. (orig.)

  8. Effect of TIPS placement on portal and splanchnic arterial blood flow in 4-dimensional flow MRI

    International Nuclear Information System (INIS)

    To assess changes in portal and splanchnic arterial haemodynamics in patients undergoing transjugular intrahepatic portosystemic shunt (TIPS) using four-dimensional (4D) flow MRI, a non-invasive, non-contrast imaging technique. Eleven patients undergoing TIPS implantation were enrolled. K-t GRAPPA accelerated non-contrast 4D flow MRI of the liver vasculature was applied with acceleration factor R = 5 at 3Tesla. Flow analysis included three-dimensional (3D) blood flow visualization using time-resolved 3D particle traces and semi-quantitative flow pattern grading. Quantitative evaluation entailed peak velocities and net flows throughout the arterial and portal venous (PV) systems. MRI measurements were taken within 24 h before and 4 weeks after TIPS placement. Three-dimensional flow visualization with 4D flow MRI revealed good image quality with minor limitations in PV flow. Quantitative analysis revealed a significant increase in PV flow (562 ± 373 ml/min before vs. 1831 ± 965 ml/min after TIPS), in the hepatic artery (176 ± 132 ml/min vs. 354 ± 140 ml/min) and combined flow in splenic and superior mesenteric arteries (770 ml/min vs. 1064 ml/min). Shunt-flow assessment demonstrated stenoses in two patients confirmed and treated at TIPS revision. Four-dimensional flow MRI might have the potential to give new information about the effect of TIPS placement on hepatic perfusion. It may explain some unexpected findings in clinical observation studies. (orig.)

  9. Clinical Research

    DEFF Research Database (Denmark)

    Christensen, Irene

    2016-01-01

    for years to come. This paper seeks to provide insights into ramp-up management studies through providing an agenda for conducting collaborative clinical research and extend this area by proposing how clinical research could be designed and executed in the Ramp- up management setting.......This paper is about the logic of problem solving and the production of scientific knowledge through the utilisation of clinical research perspective. Ramp-up effectiveness, productivity, efficiency and organizational excellence are topics that continue to engage research and will continue doing so...

  10. Titrated flow versus fixed flow Bubble Nasal CPAP for respiratory distress in preterm neonates.

    Directory of Open Access Journals (Sweden)

    Srinivas eMurki

    2015-10-01

    Full Text Available Background: The clinical effects of a pre-fixed flow of air-oxygen versus a flow titrated according to visible bubbling are not well understood.Objective: To compare the effects of a fixed flow (5 L/min and titrated flow ( flow just enough to ensure bubbling at different set pressures on delivered intra-prong pressure, gas exchange and clinical parameters in preterm infants on bubble CPAP for respiratory distress.Methods: Preterm infants less than 35 weeks gestation on bubble CPAP and less than 96 h of age, were enrolled in this cross over study. They were subjected to 30 minute periods of titrated flow and fixed flow. At the end of both epochs, gas flow rate, set pressure, FiO2, SpO2, Silverman retraction score, respiratory rate , abdominal girth, and blood gases were recorded. The delivered intra-prong pressure was measured by an electronic manometer. Results: Sixty nine recordings were made in 54 infants. For each of the set CPAP pressures (4, 5 and 6 cm H2O, the mean delivered pressure with a fixed flow of 5 L/min was higher than that delivered by the titrated flow. During the fixed flow epoch, the delivered pressure was closer to and higher than the set pressure resulting in higher PaO2 and lower PaCO2 as compared to titrated flow epoch. In the titrated flow period, the delivered pressure was consistently lower than the set pressure. Conclusion: In preterm infants on bubble CPAP with set pressures of 4 to 6 cm H2O, a fixed flow of 5 L/min is more effective than a flow titrated to ensure adequate visible bubbling. It achieves higher delivered pressures, better oxygenation and ventilation.

  11. Group flow, complex flow, unit vector flow, and the (2+ϵ)-flow conjecture

    DEFF Research Database (Denmark)

    Thomassen, Carsten

    2014-01-01

    that every 14-edge-connected graph has a flow whose flow values are the five roots of unity in the complex plane. Any such flow is balanced modulo 5. So, if the edge-connectivity 14 can be reduced to 9, then the 5-flow conjecture follows, as observed by F. Jaeger. We use vector flow to prove that, for each...

  12. Clinical photography.

    Science.gov (United States)

    Jakowenko, Janelle

    2009-01-01

    Digital cameras, when used correctly, can provide the basis for telemedicine services. The increasing sophistication of digital cameras, combined with the improved speed and availability of the Internet, make them an instrument that every health-care professional should be familiar with. Taking satisfactory images of patients requires clinical photography skills. Photographing charts, monitors, X-ray films and specimens also requires expertise. Image capture using digital cameras is often done with insufficient attention, which can lead to inaccurate study results. The procedures in clinical photography should not vary from camera to camera, or from country to country. Taking a photograph should be a standardised process. There are seven main scenarios in clinical photography and health professionals who use cameras should be familiar with all of them. Obtaining informed consent prior to photography should be a normal part of the clinical photography routine.

  13. Clinical supervision.

    Science.gov (United States)

    Goorapah, D

    1997-05-01

    The introduction of clinical supervision to a wider sphere of nursing is being considered from a professional and organizational point of view. Positive views are being expressed about adopting this concept, although there are indications to suggest that there are also strong reservations. This paper examines the potential for its success amidst the scepticism that exists. One important question raised is whether clinical supervision will replace or run alongside other support systems.

  14. Phase flow rate measurements of annular flows

    OpenAIRE

    Al-Yarubi, Qahtan

    2010-01-01

    In the international oil and gas industry multiphase annular flow in pipelines and wells is extremely important, but not well understood. This thesis reports the development of an efficient and cheap method for measuring the phase flow rates in two phase annular and annular mist flow, in which the liquid phase is electrically conducting, using ultrasonic and conductance techniques. The method measures changes in the conductance of the liquid film formed during annular flow and uses these to c...

  15. Flow of Aqueous Humor

    Science.gov (United States)

    ... Facebook Twitter Google Plus Email Print this page Flow of Aqueous Humor Most, but not all, forms ... aqueous humor) produced by the eye's ciliary body flows out freely (follow blue arrow). Aqueous humor flows ...

  16. The Physics of Coronary Blood Flow

    CERN Document Server

    Zamir, M

    2005-01-01

    Coronary blood flow is blood flow to the heart for its own metabolic needs. In the most common form of heart disease there is a disruption in this flow because of obstructive disease in the vessels that carry the flow. The subject of coronary blood flow is therefore associated mostly with the pathophysiology of this disease, rarely with dynamics or physics. Yet, the system responsible for coronary blood flow, namely the "coronary circulation," is a highly sophisticated dynamical system in which the dynamics and physics of the flow are as important as the integrity of the conducting vessels. While an obstruction in the conducting vessels is a fairly obvious and clearly visible cause of disruption in coronary blood flow, any discord in the complex dynamics of the system can cause an equally grave, though less conspicuous, disruption in the flow. This book is devoted specifically to the dynamics and physics of coronary blood flow. While relevance to the clinical and pathophysiological issues is clearly maintaine...

  17. Liver angioscintigraphy: clinical applications.

    Science.gov (United States)

    Dragoteanu, Mircea; Cotul, Sabin O; Pîgleşan, Cecilia; Tamaş, Stefan

    2004-03-01

    Liver angioscintigraphy (LAS) is a radio-isotope method for the investigation of liver perfusion and its alteration in various hepatic diseases. It measures the arterial and portal venous fractions of total liver blood flow. The percentage of liver blood flow supplied by hepatic artery is estimated mathematically by the hepatic perfusion index (HPI), normally between 25 % and 40 %. The decrease of portal blood flow in liver cirrhosis is compensated ("buffer" mechanisms) by increased arterial supply, with higher HPI value. For a patient with chronic liver disease, HPI over 50% suggests arterialization of hepatic perfusion, guiding the diagnose to liver cirrhosis. Splenic curve is completing the diagnostic information of the hepatic curve. Corroborated with per rectal scintigraphy and liver SPECT, LAS offers a good hemodynamic staging of chronic inflammatory liver diseases. Malignant tumors (primitive or metastases) increase the arterial supply of the liver and decrease the portal flow, HPI being over 50% (currently 65 % - 90 %). Benign tumors do not change portal/arterial liver blood flow ratio. SPECT or non-scintigraphic morphological investigations increase the diagnostic value of LAS for primitive liver tumors. Liver cancer occurring on cirrhosis is a limitative factor for LAS. Hepatic metastases increase the arterial perfusion (and HPI value) very quickly, before their size allows morphologic imaging diagnosis. LAS is therefore an early method to diagnose liver metastases being especially used in colorectal cancer. Other clinical applications of LAS are: follow up of liver toxicity of drugs, evaluation of portal vein permeability, post surgery follow up of the liver tumor patients. PMID:15054528

  18. Flow Distances on Open Flow Networks

    CERN Document Server

    Guo, Liangzhu; Shi, Peiteng; Wang, Jun; Huang, Xiaohan; Zhang, Jiang

    2015-01-01

    Open flow network is a weighted directed graph with a source and a sink, depicting flux distributions on networks in the steady state of an open flow system. Energetic food webs, economic input-output networks, and international trade networks, are open flow network models of energy flows between species, money or value flows between industrial sectors, and goods flows between countries, respectively. Flow distances (first-passage or total) between any given two nodes $i$ and $j$ are defined as the average number of transition steps of a random walker along the network from $i$ to $j$ under some conditions. They apparently deviate from the conventional random walk distance on a closed directed graph because they consider the openness of the flow network. Flow distances are explicitly expressed by underlying Markov matrix of a flow system in this paper. With this novel theoretical conception, we can visualize open flow networks, calculating centrality of each node, and clustering nodes into groups. We apply fl...

  19. The Effect of Pentoxifylline on bcl-2 Gene Expression Changes in Hippocampus after Ischemia-Reperfusion in Wistar Rats by a Quatitative RT-PCR Method

    OpenAIRE

    Sari, Soyar; Hashemi, Mehrdad; Mahdian, Reza; Parivar, Kazem; Rezayat, Mehdi

    2013-01-01

    Ischemia-reperfusion injury is the tissue damage caused when blood supply returns to the tissue after a period of ischemia or lack of oxygen. Ischemia-reperfusion brain injury initiates an inflammatory response involving the expression of adhesion molecules and cytokines. Twenty–four male Wistar rats (250-300 g body wt) were used in this study. The animals were divided into four groups of 6 rats each: I: Control group that was subjected to ischemia-reperfusion, II: Ischemia-reperfusion group ...

  20. Retinal blood flow in diabetic retinopathy.

    OpenAIRE

    Patel, V.; Rassam, S; NEWSOM, R.; Wiek, J; Kohner, E.

    1992-01-01

    OBJECTIVES--(a) To report on the basic parameters of retinal blood flow in a population of diabetic patients with and without retinopathy and non-diabetic controls; (b) to formulate a haemodynamic model for the pathogenesis of diabetic retinopathy from this and other studies. DESIGN--Laser-Doppler velocimetry and computerised image analysis to determine retinal blood flow in a large cross sectional study. SETTING--Diabetic retinopathy outpatient clinic. SUBJECTS--24 non-diabetic controls and ...

  1. Advanced Analysis Techniques for Intra-cardiac Flow Evaluation from 4D Flow MRI

    OpenAIRE

    van der Geest, Rob J; Garg, Pankaj

    2016-01-01

    Purpose of the Review Time-resolved 3D velocity-encoded MR imaging with velocity encoding in three directions (4D Flow) has emerged as a novel MR acquisition technique providing detailed information on flow in the cardiovascular system. In contrast to other clinically available imaging techniques such as echo-Doppler, 4D Flow MRI provides the 3D Flow velocity field within a volumetric region of interest over the cardiac cycle. This work reviews the most recent advances in the development and ...

  2. The clinical effect of nursing interventions on abnormal umbilical artery blood flow%护理干预对异常脐动脉血流影响的临床作用

    Institute of Scientific and Technical Information of China (English)

    张蓉萍; 唐明霞; 蔡秋香; 汪萍

    2012-01-01

    Objective To explore the effect of nursing interventions on the changes of S/D ratio of umbilical artery blood flow with different sleeping postures and pregnancy outcomes. Methods A total of 99 pregnant women with a gestational duration of 28 to 42 weeks, who had abnormal S/D ratios in umbilical artery blood flow were randomly divided into intervention group and control group. The intervention group was asked to take different sleeping postures based the different S/D ratios including horizontal posture, left - lateral posture and right - lateral posture while the control group was not told in terms of sleeping postures. Results 39.6% pregnant women (19/48) in the intervention group had S/D ratios return to the normal range after proper instructions in sleeping postures, which was higher than the 17.6% (9/51) in the control group. The difference was statistically significant (P<0.05). The rates of cesarean section, fetal growth restriction, premature delivery, fetal distress, asphxia neonatorum, oligohysramnios, cloudy amniotic fluid in the intervention group were reduced (F<0.05). Conclusion To take proper sleeping postures may improve umbilical artery blood flow, bring S/D ratio back to the normal range, lower rates of cesarean section, reduce pregnancy complications and improve the perinatal infants prognosis.%目的 探讨护理干预下不同睡眠体位脐动脉血流S/D比值的变化及对妊娠结局的影响.方法 将99例妊娠28-42周经多普勒超声检测脐动脉血流S/D比值异常增高的孕妇随机分为干预组和对照组,干预组根据在平卧位、左侧卧位及右侧卧位3个不同体位时的S/D比值,对孕妇睡眠体位进行指导,而对照组未特意嘱咐睡眠体位.结果 干预组经指导采取正确睡眠体位后,有39.6%(19/48)的孕妇异常S/D比值降至孕周正常值,明显高于对照组的17.6%(9/51),差异有统计学意义(P<0.05);剖宫产、胎儿宫内生长受限、早产

  3. 分析彩色多普勒超声对乳腺肿块的临床诊断价值%Analysis of Color Doppler Flow Imaging (CDFI) in the Value of Clinical Diagnosis of Breast Lumps

    Institute of Scientific and Technical Information of China (English)

    左桂枝

    2015-01-01

    目的:对在彩色多普勒超声下,对良恶性乳腺肿块的不同表现情况进行研究和分析。方法对我院此次所收治的103例乳腺良性病变和86例乳腺癌患者采用彩色多普勒超声进行检查。结果经过研究发现,对乳腺良性病变和乳腺癌患者采用彩色多普勒超声进行检查,其存在不同的特点。结论在临床上,对乳腺良性病变和乳腺癌患者采用彩色多普勒超声进行检查,能够为临床诊断提供一定的参考依据。%Objective To under the color doppler ultrasound, the benign and malignant breast tumors of research and analysis on the different situation. Methods In our hospital treated 103 cases of breast benign lesions and by the 86 breast cancer patients by color Doppler lfow imaging (CDFI) for inspection. Results Through the study found that patients with breast benign lesions and breast cancer using color Doppler ultrasound to check, the existence of different features. Conclusion Clinically, patients with breast benign lesions and breast cancer using color doppler ultrasound to check, can provide certain reference basis for clinical diagnosis.

  4. Clinical practice

    OpenAIRE

    de Winter, J. Peter; de Vries, Machteld A. G.; Zimmermann, Luc J. I.

    2010-01-01

    The most important goal of introducing noninvasive ventilation (NIV) has been to decrease the need for intubation and, therefore, mechanical ventilation in newborns. As a result, this technique may reduce the incidence of bronchopulmonary dysplasia (BPD). In addition to nasal CPAP, improvements in sensors and flow delivery systems have resulted in the introduction of a variety of other types of NIV. For the optimal application of these novelties, a thorough physiological knowledge of mechanic...

  5. Clinical cases

    International Nuclear Information System (INIS)

    This presentation is about clinical cases and the contribution of the PET - CT Fag application in the diagnosis and treatment of different types of cancer. The cases presented were: neck diseases, epidermoid carcinoma, liver damage and metastasize, lymphoma, thrombosis, colonic cancer and lung disease

  6. The Jacobi flow

    OpenAIRE

    Michor, Peter W.

    1996-01-01

    The geodesic flow on the tangent bundle is the flow of a certain vector field which is called the spray $S:TM\\to TTM$. The flow lines of the vector field $\\ka_{TM}\\o TS:TTM\\to TTTM$ project to the Jacobi fields on $TM$. This could be called the Jacobi flow.

  7. [Clinical pathology].

    Science.gov (United States)

    Dimitrijević, Jovan

    2006-05-01

    This work describes the basic elements of pathology used in clinical practice. Pathology plays an important role in clinical and scientific work, but only a few areas of pathology will be covered. Although the contribution of oncological and surgical pathology to therapy is the most well known, the cases chosen here will involve infectious pathology, diseases of the kidney and the liver, autoimmune diseases, as well as organ transplantation. Especially important is the description of methods that enable more accurate morphological diagnoses, such as histochemistry, immunohistochemistry, immunofluorescence, and electronic microscopy. Previous experience and joint work with clinical doctors have enabled the definition of significant morphological elements as well as of essential methods of pathohistological diagnosis. Besides, as is often the case, although disease symptoms are difficult to discern and biochemical results do not show significant changes compared to normal values, the results of biopsy come as a surprise to clinical doctors. For example, in virus hepatitis B involving so-called asymptomatic HBsAg carriers, we discovered every morphological form of hepatitis, from minimal lesions to chronic, persistent, and active hepatitis. With hepatitis C, certain morphological lesions point to the etiopathogenesis of this disease and thus help to confirm the diagnosis and to instigate therapy on time. Another significant experience involves kidney biopsies in cases when clinical findings are asymptomatic. Often, in such cases, morphological findings point to glomerulonephritis and glomerulopathy at different stages. Timely and subtle morphological diagnostics offer a more precise explanation for the pathological injury of tissues than other diagnostic methods. In this way, by adopting new methods, the work of pathologists is included more and more in everyday clinical practice. The inclusion of pathologists in a transplantation team makes sure a proper selection of

  8. Blood flow autoregulation in pedicled flaps

    DEFF Research Database (Denmark)

    Bonde, Christian T; Holstein-Rathlou, Niels-Henrik; Elberg, Jens J

    2009-01-01

    INTRODUCTION: Clinical work on the blood perfusion in skin and muscle flaps has suggested that some degree of blood flow autoregulation exists in such flaps. An autoregulatory mechanism would enable the flap to protect itself from changes in the perfusion pressure. The purpose of the present study...... was to evaluate if, and to what extent, a tissue flap could compensate a reduction in blood flow due to an acute constriction of the feed artery. Further, we wanted to examine the possible role of smooth muscle L-type calcium channels in the autoregulatory mechanism by pharmacological intervention with the L......-type calcium channel blocker nimodipine and the vasodilator papaverine. MATERIAL AND METHODS: Pedicled flaps were raised in pigs. Flow in the pedicle was reduced by constriction of the feed artery (n=34). A transit time flow probe measured the effect on blood flow continuously. Following this, three different...

  9. Flow chemistry is starting to flow

    OpenAIRE

    Duisterwinkel, A.E.

    2012-01-01

    One good thing about this symposium on flow chemistry is that at least half of the papers was on actual applications: summarized one member of the audience of the IPIT symposium in Rotterdam, 25 May 2012. This remark can be viewed as a compliment to the organizer, TNO, a Dutch contract research organization. More importantly, it shows that flow chemistry is, slowly but steadily, being accepted in the production of fine chemicals and pharmaceutics. In order to get flow chemistry accepted in th...

  10. Thermal flow micro sensors

    OpenAIRE

    Elwenspoek, M

    1999-01-01

    A review is given on sensors fabricated by silicon micromachining technology using the thermal domain for the measurement of fluid flow. Attention is paid especially to performance and geometry of the sensors. Three basic types of thermal flow sensors are discussed: anemometers, calorimetric flow sensors and time of flight flow sensors. Anemometers may comprise several heaters and temperature sensors and from a geometric point of view are similar sometimes for calorimetric flow sensors. We fi...

  11. Clinical biochemistry

    Science.gov (United States)

    Alexander, W. C.; Leach, C. S.; Fischer, C. L.

    1975-01-01

    The objectives of the biochemical studies conducted for the Apollo program were (1) to provide routine laboratory data for assessment of preflight crew physical status and for postflight comparisons; (2) to detect clinical or pathological abnormalities which might have required remedial action preflight; (3) to discover as early as possible any infectious disease process during the postflight quarantine periods following certain missions; and (4) to obtain fundamental medical knowledge relative to man's adjustment to and return from the space flight environment. The accumulated data presented suggest that these requirements were met by the program described. All changes ascribed to the space flight environment were subtle, whereas clinically significant changes were consistent with infrequent illnesses unrelated to the space flight exposure.

  12. 经颅多普勒超声、经颅彩色超声及彩色多普勒超声联合诊断椎动脉狭窄临床分析%Transcranial Doppler Ultrasonography and Transcranial Color Doppler Flow Imaging and Color Doppler Ultrasonography Clinical Analysis on Combined Diagnosis of Vertebral Artery Stenosis

    Institute of Scientific and Technical Information of China (English)

    常玉洁

    2015-01-01

    目的:探究经颅多普勒超声、经颅彩色超声及彩色多普勒超声联合诊断椎动脉狭窄的临床意义。方法回顾性分析2010年5月—2014年5月,根据这段时间内对2000份临床资料的分析,针对缺血性脑血管病患者进行治疗,一般通过两项常规检查即CDFI和TCD、经过脑血管造影(DSA),在2000例患者中有344例被确定属于ICA单、双侧狭窄或闭塞的情况。以DSA为标准,计算CDFI、TCD及二者联合检查结果的符合率以判断。结果CDFI诊断检测结果符合率为82%,TCD为77%,联合诊断为93%,差异有统计学意义。结论经颅多普勒超声、经颅彩色超声及彩色多普勒超声联合诊断椎动脉狭窄临床效果明显,值得推广应用。%Objective To explore the clinical significance of combined diagnosis in vertebral artery stenosis using Transcranial Doppler ultrasonography and Transcranial color Doppler flow imaging and color Doppler ultrasound. Methods Retrospectively ana-lyzed 2000 clinical data of patients treated in our hospital with ischemic cerebral vascular disease from May 2010 to May 2014. CDFI and TCD were two general examinations of patients, and after cerebral angiography (DSA), within 2000 patients 344 cases were diagnosed as single and double side-ICA stenosis or occlusion. Using DSA as a standard, calculate the coincidence rate of the test results of CDFI, TCD and CDFI combined with TCD. Results The diagnostic coincidence rate of CDFI testing results was 82%, and that of TCD was 77%, while that of CDFI combined with TCD was 93%. Conclusion The clinical effect of Transcranial Doppler ultrasonography and Transcranial color Doppler flow imaging and color Doppler ultrasound is obvious in the diagnosis of vertebral artery stenosis, and it should be widely applied.

  13. 冠脉造影正常患者内皮功能与冠脉血流储备能力的研究%Clinical study of Endothelial Function and Coronary Flow Reserve in Patients with Normal Coronary Arteriograms

    Institute of Scientific and Technical Information of China (English)

    张勇; 唐小霞; 曹邦明; 任淑红; 王新宇; 陈兴新

    2014-01-01

    Objective Coronary Flow Reserve ( CFR ) of patients with normal coronary arteriograms were measured by the use of angiographic digital tracking and endothelial function were evaluated by intracoronary acetyl -choline(Ach) test and high-sensitivity C-reactive protein (hsCRP) levels.The change of CFR and endothelial function in patients with different risk factors were observed and analysed .Methods In selected 118 cases ( The mean age 61 ±11 years old ) with suspected coronary artery disease were divided into 6 groups according to different risk factors:hypertension , hypercholesterolemia , obesity , smoking , type 2 diabetes mellitus and ≥2 risk factors groups while 24 healthy subjects ( The mean age 56 ±12 years old ) as matched .CFR of patients with normal coro-nary arteriograms were measured by the use of angiographic digital tracking and endothelial function were evaluated by intracoronary Ach test and hsCRP levels .The change of CFR , positive rates of Ach test , hsCRP levels were ob-served and analysed .Results CFR in group of hypertension , smoking and≥2 risk factors were lower and positive rates of Ach test ,hsCRP levels were higher than those of the control group .CFR in group of hypercholesterolemia , Obesity , Type 2 Diabetes Mellitus groups were lower and positive rates of Ach test were higher than those of the control group but there were no significant differences between them .hsCRP levels of Type 2 Diabetes Mellitus group were higher than those of the control group .Conclusion Angiography digital tracking method can be easily used in measuring CFR .Lower CFR and endothelial dysfunction in people with different risk factors were observed in this reaserch .%目的:通过常规冠脉造影,运用数字跟踪技术软件测定冠脉造影正常患者冠脉血流储备( Coro-nary Flow Reserve,CFR),冠脉内注射乙酰胆碱(Acetylcholine,Ach)并检测高敏C反应蛋白( high Sensitivi-ty,hsCRP)含量评价内皮功能,

  14. Flow Element Models

    DEFF Research Database (Denmark)

    Heiselberg, Per; Nielsen, Peter V.

    Air distribution in ventilated rooms is a flow process that can be divided into different elements such as supply air jets, exhaust flows, thermal plumes, boundary layer flows, infiltration and gravity currents. These flow elements are isolated volumes where the air movement is controlled...... by a restricted number of parameters, and the air movement is fairly independent of the general flow in the enclosure. In many practical situations, the most convenient· method is to design the air distribution system using flow element theory....

  15. Introduction to compressible fluid flow

    CERN Document Server

    Oosthuizen, Patrick H

    2013-01-01

    IntroductionThe Equations of Steady One-Dimensional Compressible FlowSome Fundamental Aspects of Compressible FlowOne-Dimensional Isentropic FlowNormal Shock WavesOblique Shock WavesExpansion Waves - Prandtl-Meyer FlowVariable Area FlowsAdiabatic Flow with FrictionFlow with Heat TransferLinearized Analysis of Two-Dimensional Compressible FlowsHypersonic and High-Temperature FlowsHigh-Temperature Gas EffectsLow-Density FlowsBibliographyAppendices

  16. Participating in Clinical Trials

    Science.gov (United States)

    ... this page please turn Javascript on. Participating in Clinical Trials About Clinical Trials A Research Study With Human Subjects A clinical ... to treat or cure a disease. Phases of Clinical Trials Clinical trials of drugs are usually described based ...

  17. Noninvasive measurement of cerebrospinal fluid flow using an ultrasonic transit time flow sensor: a preliminary study.

    Science.gov (United States)

    Pennell, Thomas; Yi, Juneyoung L; Kaufman, Bruce A; Krishnamurthy, Satish

    2016-03-01

    OBJECT Mechanical failure-which is the primary cause of CSF shunt malfunction-is not readily diagnosed, and the specific reasons for mechanical failure are not easily discerned. Prior attempts to measure CSF flow noninvasively have lacked the ability to either quantitatively or qualitatively obtain data. To address these needs, this preliminary study evaluates an ultrasonic transit time flow sensor in pediatric and adult patients with external ventricular drains (EVDs). One goal was to confirm the stated accuracy of the sensor in a clinical setting. A second goal was to observe the sensor's capability to record real-time continuous CSF flow. The final goal was to observe recordings during instances of flow blockage or lack of flow in order to determine the sensor's ability to identify these changes. METHODS A total of 5 pediatric and 11 adult patients who had received EVDs for the treatment of hydrocephalus were studied in a hospital setting. The primary EVD was connected to a secondary study EVD that contained a fluid-filled pressure transducer and an in-line transit time flow sensor. Comparisons were made between the weight of the drainage bag and the flow measured via the sensor in order to confirm its accuracy. Data from the pressure transducer and the flow sensor were recorded continuously at 100 Hz for a period of 24 hours by a data acquisition system, while the hourly CSF flow into the drip chamber was recorded manually. Changes in the patient's neurological status and their time points were noted. RESULTS The flow sensor demonstrated a proven accuracy of ± 15% or ± 2 ml/hr. The flow sensor allowed real-time continuous flow waveform data recordings. Dynamic analysis of CSF flow waveforms allowed the calculation of the pressure-volume index. Lastly, the sensor was able to diagnose a blocked catheter and distinguish between the blockage and lack of flow. CONCLUSIONS The Transonic flow sensor accurately measures CSF output within ± 15% or ± 2 ml

  18. Noninvasive measurement of cerebrospinal fluid flow using an ultrasonic transit time flow sensor: a preliminary study.

    Science.gov (United States)

    Pennell, Thomas; Yi, Juneyoung L; Kaufman, Bruce A; Krishnamurthy, Satish

    2016-03-01

    OBJECT Mechanical failure-which is the primary cause of CSF shunt malfunction-is not readily diagnosed, and the specific reasons for mechanical failure are not easily discerned. Prior attempts to measure CSF flow noninvasively have lacked the ability to either quantitatively or qualitatively obtain data. To address these needs, this preliminary study evaluates an ultrasonic transit time flow sensor in pediatric and adult patients with external ventricular drains (EVDs). One goal was to confirm the stated accuracy of the sensor in a clinical setting. A second goal was to observe the sensor's capability to record real-time continuous CSF flow. The final goal was to observe recordings during instances of flow blockage or lack of flow in order to determine the sensor's ability to identify these changes. METHODS A total of 5 pediatric and 11 adult patients who had received EVDs for the treatment of hydrocephalus were studied in a hospital setting. The primary EVD was connected to a secondary study EVD that contained a fluid-filled pressure transducer and an in-line transit time flow sensor. Comparisons were made between the weight of the drainage bag and the flow measured via the sensor in order to confirm its accuracy. Data from the pressure transducer and the flow sensor were recorded continuously at 100 Hz for a period of 24 hours by a data acquisition system, while the hourly CSF flow into the drip chamber was recorded manually. Changes in the patient's neurological status and their time points were noted. RESULTS The flow sensor demonstrated a proven accuracy of ± 15% or ± 2 ml/hr. The flow sensor allowed real-time continuous flow waveform data recordings. Dynamic analysis of CSF flow waveforms allowed the calculation of the pressure-volume index. Lastly, the sensor was able to diagnose a blocked catheter and distinguish between the blockage and lack of flow. CONCLUSIONS The Transonic flow sensor accurately measures CSF output within ± 15% or ± 2 ml

  19. Peak flow meter (image)

    Science.gov (United States)

    A peak flow meter is commonly used by a person with asthma to measure the amount of air that can be ... become narrow or blocked due to asthma, peak flow values will drop because the person cannot blow ...

  20. Urination - difficulty with flow

    Science.gov (United States)

    ... gov/ency/article/003143.htm Urination - difficulty with flow To use the sharing features on this page, ... at night? Has the force of your urine flow decreased? Do you have dribbling or leaking urine? ...

  1. Review of zonal flows

    International Nuclear Information System (INIS)

    A comprehensive review of zonal flow phenomena in plasmas is presented. While the emphasis is on zonal flows in laboratory plasmas, zonal flows in nature are discussed as well. The review presents the status of theory, numerical simulation and experiments relevant to zonal flows. The emphasis is on developing an integrated understanding of the dynamics of drift wave - zonal flow turbulence by combining detailed studies of the generation of zonal flows by drift waves, the back-interaction of zonal flows on the drift waves, and the various feedback loops by which the system regulates and organizes itself. The implications of zonal flow phenomena for confinement in, and the phenomena of fusion devices are discussed. Special attention is given to the comparison of experiment with theory and to identifying direction for progress in future research. (author)

  2. Flowing holographic anyonic superfluid

    OpenAIRE

    Jokela, Niko; Lifschytz, Gilad; Lippert, Matthew

    2014-01-01

    We investigate the flow of a strongly coupled anyonic superfluid based on the holographic D3-D7' probe brane model. By analyzing the spectrum of fluctuations, we find the critical superfluid velocity, as a function of the temperature, at which the flow stops being dissipationless when flowing past a barrier. We find that at a larger velocity the flow becomes unstable even in the absence of a barrier.

  3. Flow for Meta Control

    OpenAIRE

    Bulitko, Vadim

    2014-01-01

    The psychological state of flow has been linked to optimizing human performance. A key condition of flow emergence is a match between the human abilities and complexity of the task. We propose a simple computational model of flow for Artificial Intelligence (AI) agents. The model factors the standard agent-environment state into a self-reflective set of the agent's abilities and a socially learned set of the environmental complexity. Maximizing the flow serves as a meta control for the agent....

  4. STOCHASTIC FLOWS OF MAPPINGS

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    In this paper, the stochastic flow of mappings generated by a Feller convolution semigroup on a compact metric space is studied. This kind of flow is the generalization of superprocesses of stochastic flows and stochastic diffeomorphism induced by the strong solutions of stochastic differential equations.

  5. OpenFlow cookbook

    CERN Document Server

    Smiler S, Kingston

    2015-01-01

    This book is intended for network protocol developers, SDN controller application developers, and academics who would like to understand and develop their own OpenFlow switch or OpenFlow controller in any programming language. With basic understanding of OpenFlow and its components, you will be able to follow the recipes in this book.

  6. Thermal flow micro sensors

    NARCIS (Netherlands)

    Elwenspoek, M.

    1999-01-01

    A review is given on sensors fabricated by silicon micromachining technology using the thermal domain for the measurement of fluid flow. Attention is paid especially to performance and geometry of the sensors. Three basic types of thermal flow sensors are discussed: anemometers, calorimetric flow se

  7. Geodesic Renormalisation Group Flow

    OpenAIRE

    Dolan, Brian P

    1995-01-01

    It is shown that the renormalisation group flow in coupling constant space can be interpreted in terms of a dynamical equation for the couplings analogous to viscous fluid flow under the action of a potential. For free scalar field theory the flow is geodesic in two dimensions, while for $D \

  8. Research Advances: DRPS--Let The Blood Flow!

    Science.gov (United States)

    King, Angela G.

    2007-01-01

    A team from the University of Pittsburgh's McGowan Institute for Regenerative Medicine has shown the potential for clinical use of the drag-reducing polymer (DRP) poly(N-vinylformamide), or PNVF. The high molecular weight PNVF is shown to reduce resistance to turbulent flow in a pipe and to enhance blood flow in animal models and it also…

  9. Transverse correlation: An efficient transverse flow estimator - initial results

    DEFF Research Database (Denmark)

    Holfort, Iben Kraglund; Henze, Lasse; Kortbek, Jacob;

    2008-01-01

    Color flow mapping has become an important clinical tool, for diagnosing a wide range of vascular diseases. Only the velocity component along the ultrasonic beam is estimated, so to find the actual blood velocity, the beam to flow angle has to be known. Because of the unpredictable nature...

  10. An Active, Collaborative Approach to Learning Skills in Flow Cytometry

    Science.gov (United States)

    Fuller, Kathryn; Linden, Matthew D.; Lee-Pullen, Tracey; Fragall, Clayton; Erber, Wendy N.; Röhrig, Kimberley J.

    2016-01-01

    Advances in science education research have the potential to improve the way students learn to perform scientific interpretations and understand science concepts. We developed active, collaborative activities to teach skills in manipulating flow cytometry data using FlowJo software. Undergraduate students were given compensated clinical flow…

  11. Flow lab.: flow visualization and simulation

    Energy Technology Data Exchange (ETDEWEB)

    Park, Chung Kyun; Cho, Won Jin; Hahn, Pil Soo [Korea Atomic Energy Research Institute, Taejeon (Korea, Republic of)

    2005-11-15

    The experimental setups for flow visualization and processes identification in laboratory scale (so called Flow Lab.) has developed to get ideas and answer fundamental questions of flow and migration in geologic media. The setup was made of a granite block of 50x50cm scale and a transparent acrylate plate. The tracers used in this experiments were tritiated water, anions, and sorbing cations as well as an organic dye, eosine, to visualize migration paths. The migration plumes were taken with a digital camera as a function of time and stored as digital images. A migration model was also developed to describe and identify the transport processes. Computer simulation was carried out not only for the hydraulic behavior such as distributions of pressure and flow vectors in the fracture but also for the migration plume and the elution curves.

  12. Annular Flow Distribution test

    International Nuclear Information System (INIS)

    This report documents the Babcock and Wilcox (B ampersand W) Annular Flow Distribution testing for the Savannah River Laboratory (SRL). The objective of the Annular Flow Distribution Test Program is to characterize the flow distribution between annular coolant channels for the Mark-22 fuel assembly with the bottom fitting insert (BFI) in place. Flow rate measurements for each annular channel were obtained by establishing ''hydraulic similarity'' between an instrumented fuel assembly with the BFI removed and a ''reference'' fuel assembly with the BFI installed. Empirical correlations of annular flow rates were generated for a range of boundary conditions

  13. Granular media: flow & agitations

    OpenAIRE

    Dijksman, Joshua Albert

    2009-01-01

    This thesis is about weakly driven granular flows and suspensions. Chapter 1 is an overview of the current knowledge of slow granular flows in so-called split-bottom geometries, which in essence consist of a disk rotating at the bottom of a container. In chapter 2 we study dry granular flows in this split-bottom geometry, both in the frictional, slow, rate-independent regime, and in the liquid-like, rate dependent regime which is reached for faster flows. Chapters 3-5 deal with the flow of su...

  14. Signal flow analysis

    CERN Document Server

    Abrahams, J R; Hiller, N

    1965-01-01

    Signal Flow Analysis provides information pertinent to the fundamental aspects of signal flow analysis. This book discusses the basic theory of signal flow graphs and shows their relation to the usual algebraic equations.Organized into seven chapters, this book begins with an overview of properties of a flow graph. This text then demonstrates how flow graphs can be applied to a wide range of electrical circuits that do not involve amplification. Other chapters deal with the parameters as well as circuit applications of transistors. This book discusses as well the variety of circuits using ther

  15. Lateral flow strip assay

    Science.gov (United States)

    Miles, Robin R.; Benett, William J.; Coleman, Matthew A.; Pearson, Francesca S.; Nasarabadi, Shanavaz L.

    2011-03-08

    A lateral flow strip assay apparatus comprising a housing; a lateral flow strip in the housing, the lateral flow strip having a receiving portion; a sample collection unit; and a reagent reservoir. Saliva and/or buccal cells are collected from an individual using the sample collection unit. The sample collection unit is immersed in the reagent reservoir. The tip of the lateral flow strip is immersed in the reservoir and the reagent/sample mixture wicks up into the lateral flow strip to perform the assay.

  16. Separation of flow

    CERN Document Server

    Chang, Paul K

    2014-01-01

    Interdisciplinary and Advanced Topics in Science and Engineering, Volume 3: Separation of Flow presents the problem of the separation of fluid flow. This book provides information covering the fields of basic physical processes, analyses, and experiments concerning flow separation.Organized into 12 chapters, this volume begins with an overview of the flow separation on the body surface as discusses in various classical examples. This text then examines the analytical and experimental results of the laminar boundary layer of steady, two-dimensional flows in the subsonic speed range. Other chapt

  17. 行气活血法治疗2型糖尿病气滞血瘀证的临床研究%Clinical Study on Diabetes Type 2 of Qi Stagnation and Blood Stasis Treated with Promoting Flow of Qi and Blood Circulation Method

    Institute of Scientific and Technical Information of China (English)

    张国梁; 刘海英; 王珏; 姚燕珍; 赵志钧; 於松达; 於孝龙; 李亚平

    2009-01-01

    To observe the effects of promoting flow of qi and blood circulation method on platelet-activating factor, plasma endothelin and nitric oxide of patients with diabetes type 2 of qi stagnation and blood stasis.Meothods: 104 cases were divided into two groups, 53 cases was treatment group, 51 cases was control. Treatment group was given jiawei taohong siwu decoction, control was given taohong siwu decoction. The changes of clinical symptoms, blood viscosity,CD62p, CD63, PAC-1, ET and NO were observed and recorded.Results: To compare with before treated, the changes of clinical symptoms, blood viscosity,CD62p, CD63, PAC-1, ET and NO were improved after treated with jiawei taohong siwu decoction or taohong siwu decoction, there was obvious difference between treatment and control groups.Conclusion: The effects of promoting flow of qi and blood circulation method on diabetes type 2 of qi stagnation and blood stasis were veritable.%目的:观察行气活血法对2型糖尿病气滞血瘀证患者血小板活化因子及血浆内皮素、一氧化氮的影响.方法:104例患者,随机分为治疗组53例,对照组51例;治疗组服用加味桃红四物汤,对照组服用桃红四物汤;观察两组临床疗效、血黏度、CD62p、CD63、PAC-1和ET、NO的变化.结果:两组治疗前后组内比较,血黏度、CD62p、CD63、PAC-1和ET、NO的差异,治疗组有非常显著性意义(P<0.01),对照组有显著性意义(P<0.05);组间比较,差异有显著性意义(P<0.05).结论:行气活血法能降低2型糖尿病患者的血黏度,抑制血小板活化,调节内皮素和一氧化氮的分泌失衡,作用较活血化瘀法显著.

  18. 人类疱疹病毒6型荧光定量PCR检测方法的建立和应用%Establishment and clinical application of TapMan real-time RT-PCR method for detection of HHV-6

    Institute of Scientific and Technical Information of China (English)

    陈倩倩; 张兵; 谢志萍; 李金松; 高寒春; 肖霓光; 谢乐云; 余阗; 曾赛珍

    2013-01-01

    目的 建立人类疱疹病毒6型(HHV-6)荧光定量PCR检测方法,并检测临床样本.方法 根据文献合成HHV-6 U65-66基因片段的特异性引物和TaqMan探针,构建质粒制备标准品,评估该方法的特异性、灵敏度和重复性;并用该方法检测93份临床诊断为病毒性脑炎的脑脊液标本.结果 本实验检测HHV-6的灵敏度为3×10(0)拷贝/μl;标准曲线间线性关系(R2)为0.999,扩增效率为97.9%;同一样本重复检测3次,组内Ct值的变异系数最大为0.61%,组间为3.13%;特异性检测中只有HHV-6阳性标本出现扩增曲线.93份临床标本中检出HHV-6阳性2例,检出率为2.15%.结论 本实验所建立的荧光定量PCR检测HHV-6的方法特异强、灵敏高、重复性好,具有应用于临床检测的潜在价值.%Objective To establish a rapid,sensitive and specific real-time PCR method for detection of Human Herpesvirus-6 (HHV-6).Methods According to thc rcfcrcncc,a pair of primcrs and a probe were designed located in U65-66 gene and to set up the standards.We established a real-time RT-PCR method for detection of HHV-6,and to verify the specificity,sensitivity,reproducibility.Results The correlation coefficient was 0.999,E =97.9%,the coefficient of variation values of Ct were 0.61% and 3.13% in real-time PCR assay for inter and intra assay,respectively.The results of all viruses were negative except of HHV-6 for the assay.The quantitative detection limit of the assay was 3 × 10(0) copies/μl.Conclusion The real-time PCR assay is highly specific,sensitive and reproducible,which can be used to quatitative detecting clinical samples.

  19. Clinical Neuroimaging of cerebral ischemia

    Energy Technology Data Exchange (ETDEWEB)

    Nakagawara, Jyoji [Nakamura Memorial Hospital, Sapporo (Japan)

    1999-06-01

    Notice points in clinical imaging of cerebral ischemia are reviewed. When cerebral blood flow is determined in acute stage of cerebral embolism (cerebral blood flow SPECT), it is important to find area of ischemic core and ischemic penumbra. When large cortex area is assigned to ischemic penumbra, thrombolytic therapy is positively adapted, but cautious correspondence is necessary when ischemic core is recognized. DWI is superior in the detection of area equivalent to ischemic core of early stage, but, in imaging of area equivalent to ischemic penumbra, perfusion image or distribution image of cerebral blood volume (CBV) by MRI need to be combined. Luxury perfusion detected by cerebral blood flow SPECT in the cases of acute cerebral embolism suggests vascular recanalization, but a comparison with CT/MRI and continuous assessment of cerebral circulation dynamics were necessary in order to predict brain tissue disease (metabolic abnormality). In hemodynamic cerebral ischemia, it is important to find stage 2 equivalent to misery perfusion by quantification of cerebral blood flow SPECT. Degree of diaschisis can indicate seriousness of brain dysfunction for lacuna infarct. Because cerebral circulation reserve ability (perfusion pressure) is normal in all areas of the low cerebral blood flow by diaschisis mechanism, their areas are easily distinguished from those of hemodynamic cerebral ischemia. (K.H.)

  20. Clinical Analysis on Therapeutic Effect of Low Molecular Weight Heparin and CSDP on Abnormal Umbilical Artery Blood Flow in the Third Trimester of Pregnancy%低分子肝素联合复方丹参滴丸治疗妊娠中晚期脐动脉血流异常的临床分析

    Institute of Scientific and Technical Information of China (English)

    汪群

    2013-01-01

    Objective To investigate the clinical effects of low molecular weight heparin (LMWH) combined with CSDP on pregnant women with umbilical cord blood flow S/D value abnormality in the third trimester of pregnancy. Methods According to different medications, 89 pregnant women with umbilical cord blood flow S/D value abnormality in the third trimester of pregnancy were divided into two groups. The control group was given LMWH, while the observation group was treated with LMWH plus CSDP. The changes in umbilical cord blood flow and coagulation function were observed before and after the treatment. Results Compared with before the treatment, S/D ratio, PI and RI of pregnant women of two groups were significantly reduced after the treatment, and the differences were statistically significant. There were statistically significant differences in PI between the two groups (Ρ<0.001). After the treatment, descending rate of umbilical artery S/D ratio and treatment duration in the observation group were superior to those of control group (P<0.001, P<0.01). Conclusions Combined use of LMWH and CSDP in treating umbilical cord blood flow S/D value abnormality has the advantages of increasing placental blood flow and faster descending umbilical artery S/D ratio; moreover, it has no effect on blood coagulation. The remedy is worthy of popularization and application.%目的 探讨低分子肝素联合复方丹参滴丸治疗妊娠中晚期脐动脉血流异常的临床效果. 方法 将89例妊娠中晚期脐动脉血流异常的患者,按治疗方案不同分为两组,对照组给予低分子肝素治疗;观察组加用复方丹参滴丸治疗.观察两组治疗前后脐血流变化及凝血功能的变化. 结果 两组孕妇治疗后S/D比值、PI、RI均明显降低,与治疗前比较差异均有统计学意义;对照组凝血指标搏动指数与观察组比较差异有统计学意义(P<0.001);观察组患者治疗后脐动脉血流S/D比值下降速度及治

  1. In vitro validation of volumetric blood flow measurement using Doppler flow wire.

    Science.gov (United States)

    Jenni, R; Kaufmann, P A; Jiang, Z; Attenhofer, C; Linka, A; Mandinov, L

    2000-10-01

    Determination of any volumetric blood flow requires assessment of mean blood flow velocity and vessel cross-sectional area. For evaluation of coronary blood flow and flow reserve, however, assessment of average peak velocity alone is widely used, but changes in velocity profile and vessel area are not taken into account. We studied the feasibility of a new method for calculation of volumetric blood flow by Doppler power using a Doppler flow wire. An in vitro model with serially connected silicone tubes of known lumen diameters (1.5, 2.0, 2.5, 3.0, 3.5 and 4.0 mm) and pulsatile blood flow ranging from 10 to 200 mL/min was used. A Doppler flow wire was connected to a commercially available Doppler system (FloMap(R), Cardiometrics) for online calculation of the zeroth (M(0)) and the first (M(1)) Doppler moment, as well as mean flow velocity (V(m)). Two different groups of sample volumes (at different gate depths) were used: 1. two proximal sample volumes lying completely within the vessel were required to evaluate the effect of scattering and attenuation on Doppler power, and 2. distal sample volumes intersecting completely the vessel lumen to assess the vessel cross-sectional area. Area (using M(0)) and V(m) (using M(1)/M(0)) obtained from the distal gates were corrected for scattering and attenuation by the data obtained from the proximal gates, allowing calculation of absolute volumetric flow. These results were compared to the respective time collected flow. Correlation between time collected and Doppler-derived flow measurements was 0.98 (p measurements in each individual tube. The mean paired flow difference between the two techniques was 1.5 +/- 9.0 mL/min (ns). Direct volumetric blood flow measurement from received Doppler power using a Doppler flow wire system is feasible. This technique may potentially be of great clinical value because it allows an accurate assessment of coronary flow and flow reserve with a commercially available flow wire system. PMID

  2. Advanced flow MRI: emerging techniques and applications.

    Science.gov (United States)

    Markl, M; Schnell, S; Wu, C; Bollache, E; Jarvis, K; Barker, A J; Robinson, J D; Rigsby, C K

    2016-08-01

    Magnetic resonance imaging (MRI) techniques provide non-invasive and non-ionising methods for the highly accurate anatomical depiction of the heart and vessels throughout the cardiac cycle. In addition, the intrinsic sensitivity of MRI to motion offers the unique ability to acquire spatially registered blood flow simultaneously with the morphological data, within a single measurement. In clinical routine, flow MRI is typically accomplished using methods that resolve two spatial dimensions in individual planes and encode the time-resolved velocity in one principal direction, typically oriented perpendicular to the two-dimensional (2D) section. This review describes recently developed advanced MRI flow techniques, which allow for more comprehensive evaluation of blood flow characteristics, such as real-time flow imaging, 2D multiple-venc phase contrast MRI, four-dimensional (4D) flow MRI, quantification of complex haemodynamic properties, and highly accelerated flow imaging. Emerging techniques and novel applications are explored. In addition, applications of these new techniques for the improved evaluation of cardiovascular (aorta, pulmonary arteries, congenital heart disease, atrial fibrillation, coronary arteries) as well as cerebrovascular disease (intra-cranial arteries and veins) are presented. PMID:26944696

  3. PIV Investigations on Secondary Flow Structures in Horizontal Slug Flows

    OpenAIRE

    Aguas Fernández, Pedro José

    2011-01-01

    Liquid and gas phases circulate horizontally through the same channel in many industrial processes. They can do it following different patterns of so-called two-phase flow. Depending on the superficial velocity of each one of the phases, the flow can vary. The different types of flows observed in horizontal pipes are bubbly flow, stratified flow,wavy flow, slug flowand annular flow. The first formal classification of flow patterns was carried out by Taitel and Dukler during the...

  4. 46 CFR 154.546 - Excess flow valve: Closing flow.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 5 2010-10-01 2010-10-01 false Excess flow valve: Closing flow. 154.546 Section 154.546... and Process Piping Systems § 154.546 Excess flow valve: Closing flow. (a) The rated closing flow of vapor or liquid cargo for an excess flow valve must be specially approved by the Commandant (CG-522)....

  5. From Medical Records to Clinical Science

    OpenAIRE

    Aickin, Mikel; Elder, Charles

    2012-01-01

    Medical records contain an abundance of information, very little of which is extracted and put to clinical use. Increasing the flow of information from medical records to clinical practice requires methods of analysis that are appropriate for large nonintervention studies. The purpose of this article is to explain in nontechnical language what these methods are, how they differ from conventional statistical analyses, and why the latter are generally inappropriate. This is important because of...

  6. Defining pulsatility during continuous-flow ventricular assist device support.

    Science.gov (United States)

    Soucy, Kevin G; Koenig, Steven C; Giridharan, Guruprasad A; Sobieski, Michael A; Slaughter, Mark S

    2013-06-01

    Continuous-flow ventricular assist devices (CVADs) have gained widespread use as an effective clinical therapy for patients with advanced-stage heart failure. Axial and centrifugal CVADs have been successfully used as bridge-to-transplant and destination therapy. CVADs are smaller, more reliable, and less complex than the first-generation pulsatile-flow ventricular assist devices. Despite their recent clinical success, arteriovenous malformations, gastrointestinal bleeding, hemorrhagic strokes, aortic valve insufficiency, and valve fusion have been reported in heart failure patients supported by CVADs. It has been hypothesized that diminished arterial pressure and flow pulsatility delivered by CVAD may be a contributing factor to these adverse events. Subsequently, the clinical significance of vascular pulsatility continues to be highly debated. Studies comparing pulsatile-flow and continuous-flow support have presented conflicting findings, largely due to variations in device operation, support duration, and the criteria used to quantify pulsatility. Traditional measurements of pulse pressure and pulsatility index are less effective at quantifying pulsatility for mechanically derived flows, particularly with the growing trend of CVAD speed modulation to achieve various pulsatile flow patterns. Kinetic measurements of energy equivalent pressure and surplus hemodynamic energy can better quantify pulsatile energies, yet technologic and conceptual challenges are impeding their clinical adaption. A review of methods for quantifying vascular pulsatility and their application as a research tool for investigating physiologic responses to CVAD support are presented. PMID:23540401

  7. Turbulent flow as a cause for underestimating coronary flow reserve measured by Doppler guide wire

    Directory of Open Access Journals (Sweden)

    Richartz Barbara M

    2006-03-01

    velocity below a critical Reynolds number of 500. Reaching a coronary flow velocity above the velocity of the critical Reynolds number may result in an underestimation of the CFVR caused by turbulent flow. This underestimation of the flow velocity may reach up to 22.5 % compared to the actual volumetric flow. Cardiologists should consider this phenomena in at least 20 % of patients when measuring CFVR for clinical decision making.

  8. Flows of Reactive Fluids

    CERN Document Server

    Prud'homme, Roger

    2010-01-01

    The modeling of reactive flows has progressed mainly with advances in aerospace, which gave birth to a new science called aerothermochemistry, as well as through developments in chemical and process engineering. The methods employed, the phenomena investigated, and the aims of modeling differ for each field; however, in all cases, the results obtained have considerably enriched the working knowledge of reactive flows. This work examines basic concepts and methods necessary to study reactive flows and transfer phenomena in areas such as fluid mechanics, thermodynamics, and chemistry. Specific topics covered include: * Equations of state * Transfer phenomena and chemical kinetics * Balance equations of reactive flows * Dimensionless numbers and similarity * Chemical reactors * Coupled phenomena * Turbulent flow concepts * Boundary layers and fluid layers * Reactive and nonreactive waves * Interface phenomena * Multiphase flow concepts The book presents tools of interest to graduate students, researchers in math...

  9. Thread-annular flow in vertical pipes

    Science.gov (United States)

    Frei, Ch.; Lüscher, P.; Wintermantel, E.

    2000-05-01

    Thread injection is a promising method for different minimally invasive medical applications. This paper documents an experimental study dealing with an axially moving thread in annular pipe flow. Mass flow and axial force on the thread are measured for a 0.46 mm diameter thread in pipes with diameters between 0.55 and 1.35 mm. The experiments with thread velocities of up to 1.5 ms[minus sign]1 confirm the findings of theoretical studies that for clinical requirements the radius ratio between thread and pipe is crucial for the adjustments of mass ow and force on the thread.

  10. Intelligent Multiphase Flow Measurement

    OpenAIRE

    Ibrahim, Abba A.

    2009-01-01

    The oil and gas industry’s goal of developing high performing multiphase flow metering systems capable of reducing costs in the exploitation of marginal oil and gas reserves, especially in remote environments, cannot be over emphasised. Development of a cost-effective multiphase flow meter to determine the individual phase flow rates of oil, water and gas was experimentally investigated by means of low cost, simple and non-intrusive commercially available sensors. Features from...

  11. FLOW FORMING OF AEROENGINEMATERIALS

    OpenAIRE

    Kubilay, Ceylan

    2014-01-01

    Flow forming is a fairly new technique used for the production of dimensionallyaccurate near net shaped hollow components. The process has many advantagessuch as cost effectiveness and eliminating further operations like welding, machin-ing, etc. This study focuses on the characterization of flow formed componentsto understand the process. Flow formed components are composed of differentreductions and characterization techniques are applied to reveal the resulting mi-crostructural differences...

  12. Optimizing Traffic Flow

    OpenAIRE

    Huberman, Bernardo A.; Helbing, Dirk

    1998-01-01

    We present an economics-based method for deciding the optimal rates at which vehicles are allowed to enter a highway. The method exploits the naturally occuring fluctuations of traffic flow and is flexible enough to adapt in real time to the transient flow characteristics of road traffic. Simulations based on realistic parameter values show that this strategy is feasible for naturally occuring traffic, and that even far from optimality, injection policies can improve traffic flow. Our results...

  13. TRANSIMS traffic flow characteristics

    OpenAIRE

    Nagel, Kai; Stretz, Paula; Pieck, Martin; Donnelly, Rick; Barrett, Christopher L.

    1997-01-01

    Knowledge of fundamental traffic flow characteristics of traffic simulation models is an essential requirement when using these models for the planning, design, and operation of transportation systems. In this paper we discuss the following: a description of how features relevant to traffic flow are currently under implementation in the TRANSIMS microsimulation, a proposition for standardized traffic flow tests for traffic simulation models, and the results of these tests for two different ve...

  14. Grammar flow analysis

    OpenAIRE

    Möncke, Ulrich R.

    1986-01-01

    This paper specifies the theoretical basis for the implementation of different generators of the OPTRAN system. Grammar Flow analysis transports the techniques of data flow analysis to the meta level of compiler construction. The analogon to the states in data flow analysis are the syntax trees together with some information, which is associated with trees by propagation functions. One example is the association of characteristic graphs, another example the association of sets of matching tre...

  15. Polyoxometalate flow battery

    Science.gov (United States)

    Anderson, Travis M.; Pratt, Harry D.

    2016-03-15

    Flow batteries including an electrolyte of a polyoxometalate material are disclosed herein. In a general embodiment, the flow battery includes an electrochemical cell including an anode portion, a cathode portion and a separator disposed between the anode portion and the cathode portion. Each of the anode portion and the cathode portion comprises a polyoxometalate material. The flow battery further includes an anode electrode disposed in the anode portion and a cathode electrode disposed in the cathode portion.

  16. Defining Quantum Control Flow

    OpenAIRE

    Ying, Mingsheng; Yu, Nengkun; Feng, Yuan

    2012-01-01

    A remarkable difference between quantum and classical programs is that the control flow of the former can be either classical or quantum. One of the key issues in the theory of quantum programming languages is defining and understanding quantum control flow. A functional language with quantum control flow was defined by Altenkirch and Grattage [\\textit{Proc. LICS'05}, pp. 249-258]. This paper extends their work, and we introduce a general quantum control structure by defining three new quantu...

  17. Supersonic flows over cavities

    Institute of Scientific and Technical Information of China (English)

    Tianwen FANG; Meng DING; Jin ZHOU

    2008-01-01

    The characteristics of supersonic cold flows over cavities were investigated experimentally and numer-ically, and the effects of cavities of different sizes on super-sonic flow field were analyzed. The results indicate that the ratio of length to depth L/D within the range of 5-9 has little relevance to integral structures of cavity flow. The bevel angle of the rear wall does not alter the overall structure of the cavity flow within the range of 30°-60°, but it can exert obvious effect on the evolvement of shear layer and vortexes in cavities.

  18. The other spectral flow

    CERN Document Server

    Gato-Rivera, Beatriz; Gato-Rivera, Beatriz; Rosado, Jose Ignacio

    1995-01-01

    Recently we showed that the spectral flow acting on the N=2 twisted topological theories gives rise to a topological algebra automorphism. Here we point out that the untwisting of that automorphism leads to a spectral flow on the untwisted N=2 superconformal algebra which is different from the usual one. This "other" spectral flow does not interpolate between the chiral ring and the antichiral ring. In particular, it maps the chiral ring into the chiral ring and the antichiral ring into the antichiral ring. We discuss the similarities and differences between both spectral flows. We also analyze their action on null states.

  19. A neural flow estimator

    DEFF Research Database (Denmark)

    Jørgensen, Ivan Harald Holger; Bogason, Gudmundur; Bruun, Erik

    1995-01-01

    This paper proposes a new way to estimate the flow in a micromechanical flow channel. A neural network is used to estimate the delay of random temperature fluctuations induced in a fluid. The design and implementation of a hardware efficient neural flow estimator is described. The system...... is implemented using switched-current technique and is capable of estimating flow in the μl/s range. The neural estimator is built around a multiplierless neural network, containing 96 synaptic weights which are updated using the LMS1-algorithm. An experimental chip has been designed that operates at 5 V...

  20. Excess flow shutoff valve

    Energy Technology Data Exchange (ETDEWEB)

    Kiffer, Micah S.; Tentarelli, Stephen Clyde

    2016-02-09

    Excess flow shutoff valve comprising a valve body, a valve plug, a partition, and an activation component where the valve plug, the partition, and activation component are disposed within the valve body. A suitable flow restriction is provided to create a pressure difference between the upstream end of the valve plug and the downstream end of the valve plug when fluid flows through the valve body. The pressure difference exceeds a target pressure difference needed to activate the activation component when fluid flow through the valve body is higher than a desired rate, and thereby closes the valve.

  1. Mitral and aortic valvular flow: quantification with MR phase mapping

    DEFF Research Database (Denmark)

    Søndergaard, Lise; Thomsen, C; Ståhlberg, F;

    1992-01-01

    of the flow-encoding gradient to 2.2 msec. Tested on a flow phantom simulating a severe valvular stenosis, the sequence was found to be robust for higher-order motion within the clinical velocity range. In eight healthy volunteers, mitral and aortic volume flow rates and peak velocities were quantified...... mapping is also valid for pathologic conditions. Phase mapping may be used as a noninvasive clinical tool for flow quantification in heart valve disease.......When magnetic resonance phase mapping is used to quantitate valvular blood flow, the presence of higher-order-motion terms may cause a loss of phase information. To overcome this problem, a sequence with reduced encoding for higher-order motion was used, achieved by decreasing the duration...

  2. Flow chemistry is starting to flow

    NARCIS (Netherlands)

    Duisterwinkel, A.E.

    2012-01-01

    One good thing about this symposium on flow chemistry is that at least half of the papers was on actual applications: summarized one member of the audience of the IPIT symposium in Rotterdam, 25 May 2012. This remark can be viewed as a compliment to the organizer, TNO, a Dutch contract research orga

  3. Flow rate measuring devices for gas flows

    Science.gov (United States)

    Bonfig, K. W.

    1985-07-01

    Flowrate measuring devices are described: volume meter with fixed or mobile walls; turbine meter; throttling procedure; ultrasonic and Doppler methods; vortex method; rotary flowmeter; and swinging body flow measuring procedure. Flowrate can also be measured from the force exerted on bodies immersed in a fluid or based on thermodynamical principles. The characteristics and operating envelope of each device/method are given.

  4. Quantitative evaluation fo cerebrospinal fluid shunt flow

    Energy Technology Data Exchange (ETDEWEB)

    Chervu, S.; Chervu, L.R.; Vallabhajosyula, B.; Milstein, D.M.; Shapiro, K.M.; Shulman, K.; Blaufox, M.D.

    1984-01-01

    The authors describe a rigorous method for measuring the flow of cerebrospinal fluid (CSF) in shunt circuits implanted for the relief of obstructive hydrocephalus. Clearance of radioactivity for several calibrated flow rates was determined with a Harvard infusion pump by injecting the Rickham reservoir of a Rickham-Holter valve system with 100 ..mu..Ci of Tc-99m as pertechnetate. The elliptical and the cylindrical Holter valves used as adjunct valves with the Rickham reservoir yielded two different regression lines when the clearances were plotted against flow rats. The experimental regression lines were used to determine the in vivo flow rates from clearances calculated after injecting the Rickham reservoirs of the patients. The unique clearance characteristics of the individual shunt systems available requires that calibration curves be derived for an entire system identical to one implanted in the patient being evaluated, rather than just the injected chamber. Excellent correlation between flow rates and the clinical findings supports the reliability of this method of quantification of CSF shunt flow, and the results are fully accepted by neurosurgeons.

  5. RG Flows and Bifurcations

    CERN Document Server

    Gukov, Sergei

    2016-01-01

    Interpreting RG flows as dynamical systems in the space of couplings we produce a variety of constraints, global (topological) as well as local. These constraints, in turn, rule out some of the proposed RG flows and also predict new phases and fixed points, surprisingly, even in familiar theories such as O(N) model, QED-3, or QCD-4.

  6. Gauge invariant flow equation

    CERN Document Server

    Wetterich, C

    2016-01-01

    We propose a gauge invariant flow equation for Yang-Mills theories and quantum gravity that only involves one macroscopic gauge field or metric. It is based on a projection on physical and gauge fluctuations, corresponding to a particular gauge fixing. The freedom in the precise choice of the macroscopic field can be exploited in order to keep the flow equation simple.

  7. Organocatalysis in continuous flow

    NARCIS (Netherlands)

    Berg, van den S.A.

    2016-01-01

    Continuous flow chemistry is an enabling technique in organic chemistry. Advantages include extremely fast mixing and heat transfer capabilities as well as rapid screening of reaction conditions. Combining continuous flow chemistry with solid-supported organocatalysis presents challenges that have b

  8. Traffic Flow Estimates.

    Science.gov (United States)

    Hart, Vincent G.

    1981-01-01

    Two examples are given of ways traffic engineers estimate traffic flow. The first, Floating Car Method, involves some basic ideas and the notion of relative velocity. The second, Maximum Traffic Flow, is viewed to involve simple applications of calculus. The material provides insight into specialized applications of mathematics. (MP)

  9. Biomimetic Flow Sensors

    NARCIS (Netherlands)

    Casas, J.; Liu, Chang; Krijnen, G.J.M.

    2012-01-01

    Biomimetic flow sensors are biologically inspired devices that measure the speed and direction of fluids. This survey starts by describing the role and functioning of airflow-sensing hairs in arthropods and in fishes, carries on with the biomimetic MEMS implementations, both for air and water flow s

  10. Flow og anerkendelse

    DEFF Research Database (Denmark)

    Kristensen, René

    2006-01-01

    Artiklen handler om pædagogisk perspektivering af flow i forhold til anerkendelse og kreativitet. Procedural hukommelsesdannelse inddrages i forbindelse med flowforståelsen......Artiklen handler om pædagogisk perspektivering af flow i forhold til anerkendelse og kreativitet. Procedural hukommelsesdannelse inddrages i forbindelse med flowforståelsen...

  11. Flow i hverdagen

    DEFF Research Database (Denmark)

    Andersen, Frans Ørsted; Hanssen, Nina

    Bogen afspejler et eksplorativt dansk-norsk forskningsprojekt med fokus på hverdagslivets psykiske sider, herunder størrelser som stress og flow.......Bogen afspejler et eksplorativt dansk-norsk forskningsprojekt med fokus på hverdagslivets psykiske sider, herunder størrelser som stress og flow....

  12. Microelectromechanical flow control apparatus

    Science.gov (United States)

    Okandan, Murat

    2009-06-02

    A microelectromechanical (MEM) flow control apparatus is disclosed which includes a fluid channel formed on a substrate from a first layer of a nonconducting material (e.g. silicon nitride). A first electrode is provided on the first layer of the nonconducting material outside the flow channel; and a second electrode is located on a second layer of the nonconducting material above the first layer. A voltage applied between the first and second electrodes deforms the fluid channel to increase its cross-sectional size and thereby increase a flow of a fluid through the channel. In certain embodiments of the present invention, the fluid flow can be decreased or stopped by applying a voltage between the first electrode and the substrate. A peristaltic pumping of the fluid through the channel is also possible when the voltage is applied in turn between a plurality of first electrodes and the substrate. A MEM flow control assembly can also be formed by providing one or more MEM flow control devices on a common substrate together with a submicron filter. The MEM flow control assembly can optionally include a plurality of pressure sensors for monitoring fluid pressure and determining flow rates through the assembly.

  13. Braneworld flow equations

    OpenAIRE

    Ramirez, Erandy; Liddle, Andrew

    2004-01-01

    We generalize the flow equations approach to inflationary model building to the Randall–Sundrum Type II braneworld scenario. As the flow equations are quite insensitive to the expansion dynamics, we find results similar to, though not identical to, those found in the standard cosmology.

  14. Field-Flow Fractionation.

    Science.gov (United States)

    Caldwell, Karin D.

    1988-01-01

    Describes a technique for separating samples that range over 15 orders of magnitude in molecular weight. Discusses theory, apparatus, and sample preparation techniques. Lists several types of field-flow fractionation (FFF) and their uses: sedimentation FFF, thermal FFF, flow FFF, electrical FFF, and steric FFF. (ML)

  15. Hanford basalt flow mineralogy

    International Nuclear Information System (INIS)

    Mineralogy of the core samples from five core wells was examined in some detail. The primary mineralogy study included an optical examination of polished mounts, photomicrographs, chemical analyses of feldspars, pyroxenes, metallic oxides and microcrystalline groundmasses and determination from the chemical analyses of the varieties of feldspars, pyroxenes and metallic oxides. From the primary mineralogy data, a firm understanding of the average Hanford basalt flow primary mineralogy emerged. The average primary feldspar was a laboradorite, the average pyroxene was an augite and the average metallic oxide was a solid solution of ilmenite and magnetite. Secondary mineralization consisted of vug filling and joint coating, chiefly with a nontronite-beidellite clay, several zeolites, quartz, calcite, and opal. Specific flow units also were examined to determine the possibility of using the mineralogy to trace flows between core wells. These included units of the Pomona, the Umatilla and a high chromium flow just below the Huntzinger. In the Umatilla, or high barium flow, the compositional variation of the feldspars was unique in range. The pyroxenes in the Pomona were relatively highly zoned and accumulated chromium. The high chromium flow contained chromium spinels that graded in chromium content into simple magnetites very low in chromium content. A study of the statistical relationships of flow unit chemical constituents showed that flow unit constituents could be roughly correlated between wells. The probable cause of the correlation was on-going physical-chemical changes in the source magma

  16. Environmental stratified flows

    CERN Document Server

    Armenio, Vincenzo

    2006-01-01

    The volume covers the theory of stratified flows, from basic concepts to recent developments in the area of environmental fluid mechanics. The state of art of numerical techniques suited for stratified flows is given. Results of very recent researches in the areas of environmental stratified flows are discussed with details. The topics are treated in four separate chapters. The volume gives a unified view of stratified turbulent flows, from small-scale mixing, to large-scale environmental phenomena, also including detailed discussion on interaction between turbulence and internal gravity waves. The book will serve as an important review tool for all the scientists involved in the investigation of small scale as well as geophysical stratified flows.

  17. Turbulent multiphase flows

    Science.gov (United States)

    Faeth, G. M.

    1989-01-01

    Measurements and predictions of the structure of several multiphase flows are considered. The properties of dense sprays near the exits of pressure-atomizing injectors and of noncombusting and combusting dilute dispersed flows in round-jet configurations are addressed. It is found that the properties of dense sprays exhibit structure and mixing properties similar to variable-density single-phase flows at high Reynolds numbers within the atomization regime. The degree of development and turbulence levels at the injector exit have a surprisingly large effect on the structure and mixing properties of pressure-atomized sprays, particularly when the phase densities are large. Contemporary stochastic analysis of dilute multiphase flows provides encouraging predictions of turbulent dispersion for a wide variety of jetlike flows, particle-laden jets in gases and liquids, noncondensing and condensing bubbly jets, and nonevaporating, evaporating, and combusting sprays.

  18. Vega flow assurance system

    Energy Technology Data Exchange (ETDEWEB)

    Larsen, Marit; Munaweera, Sampath

    2010-07-01

    Vega is a gas condensate field located at the west coast of Norway and developed as a tie-in to the Gjoea platform. Operator is Statoil, production startup is estimated to the end of 2010. Flow assurance challenges are high reservoir pressure and temperature, hydrate and wax control, liquid accumulation and monitoring the well/template production rates. The Vega Flow Assurance System (FAS) is a software that supports monitoring and operation of the field. The FAS is based FlowManagerTM designed for real time systems. This is a flexible tool with its own steady state multiphase- and flow assurance models. Due to the long flowlines lines and the dynamic behavior, the multiphase flow simulator OLGA is also integrated in the system. Vega FAS will be used as: - An online monitoring tool - An offline what-if simulation and validation tool - An advisory control system for well production allocation. (Author)

  19. 3D vector flow imaging

    DEFF Research Database (Denmark)

    Pihl, Michael Johannes

    The main purpose of this PhD project is to develop an ultrasonic method for 3D vector flow imaging. The motivation is to advance the field of velocity estimation in ultrasound, which plays an important role in the clinic. The velocity of blood has components in all three spatial dimensions, yet...... conventional methods can estimate only the axial component. Several approaches for 3D vector velocity estimation have been suggested, but none of these methods have so far produced convincing in vivo results nor have they been adopted by commercial manufacturers. The basis for this project is the Transverse...... on the TO fields are suggested. They can be used to optimize the TO method. In the third part, a TO method for 3D vector velocity estimation is proposed. It employs a 2D phased array transducer and decouples the velocity estimation into three velocity components, which are estimated simultaneously based on 5...

  20. flowCL: ontology-based cell population labelling in flow cytometry

    Science.gov (United States)

    Courtot, Mélanie; Meskas, Justin; Diehl, Alexander D.; Droumeva, Radina; Gottardo, Raphael; Jalali, Adrin; Taghiyar, Mohammad Jafar; Maecker, Holden T.; McCoy, J. Philip; Ruttenberg, Alan; Scheuermann, Richard H.; Brinkman, Ryan R.

    2015-01-01

    Motivation: Finding one or more cell populations of interest, such as those correlating to a specific disease, is critical when analysing flow cytometry data. However, labelling of cell populations is not well defined, making it difficult to integrate the output of algorithms to external knowledge sources. Results: We developed flowCL, a software package that performs semantic labelling of cell populations based on their surface markers and applied it to labelling of the Federation of Clinical Immunology Societies Human Immunology Project Consortium lyoplate populations as a use case. Conclusion: By providing automated labelling of cell populations based on their immunophenotype, flowCL allows for unambiguous and reproducible identification of standardized cell types. Availability and implementation: Code, R script and documentation are available under the Artistic 2.0 license through Bioconductor (http://www.bioconductor.org/packages/devel/bioc/html/flowCL.html). Contact: rbrinkman@bccrc.ca Supplementary information: Supplementary data are available at Bioinformatics online. PMID:25481008

  1. Synthetic aperture tissue and flow ultrasound imaging

    DEFF Research Database (Denmark)

    Nikolov, Svetoslav

    at every emission, which makes it possible to average over a large number of lines. This makes stationary echo canceling easier and significantly improves the velocity estimates. Only 8 emissions per plane are necessary to create the color flow map. Scanning 12 cm in depth, up to 800 planes can be obtained...... imaging applied to medical ultrasound. It is divided into two major parts: tissue and blood flow imaging. Tissue imaging using synthetic aperture algorithms has been investigated for about two decades, but has not been implemented in medical scanners yet. Among the other reasons, the conventional scanning...... and beamformation methods are adequate for the imaging modalities in clinical use - the B-mode imaging of tissue structures, and the color mapping of blood flow. The acquisition time, however, is too long, and these methods fail to perform real-time three-dimensional scans. The synthetic transmit aperture...

  2. Quantitative phase-flow MR imaging in dogs by using standard sequences: comparison with in vivo flow-meter measurements.

    Science.gov (United States)

    Pettigrew, R I; Dannels, W; Galloway, J R; Pearson, T; Millikan, W; Henderson, J M; Peterson, J; Bernardino, M E

    1987-02-01

    For evaluation of the feasibility and clinical potential of using the phase data from standard MR imaging sequences to measure blood flow, 11 vessels with diameters of 4 to 7 mm were imaged in seven dogs. The flow in either the superior mesenteric vein or the inferior vena cava was measured first at laparotomy (in ml/min) with electromagnetic flow meters. Immediately thereafter, these vessels were imaged by MR in 25-mm thick sections by using a standard spin echo (SE) 750/30 sequence with a Philips 0.5-T imager. Previous phase-flow calibration of the imager and sequence allowed calculation of the blood flow rates from the phase images that were used to measure the vessels' cross-sectional areas and blood phase values. Comparison of the measurements obtained with each technique showed a significant correlation (r = .977, p less than .05) between MR-imaging values and flow-meter measurements when the blood velocity was less than approximately 40 cm/sec, the known upper limit of the flow dynamic range for the MR hardware and sequence used. There was no correlation for blood velocities greater than 40 cm/sec. However, the range of blood flow velocities in dogs and man extends to more than 100 cm/sec. Thus, these results suggest that this technique might yield valuable adjunctive flow data in routine clinical imaging provided that improvements in hardware and software permit a larger dynamic range. PMID:2948376

  3. 体外反搏治疗对失眠患者脑血流变化情况的临床研究%The Clinical Research of Effect of External Counterpulsation Therapy on Cerebral Blood Flow of Patients with Insomnia

    Institute of Scientific and Technical Information of China (English)

    沈跃玲; 蔡亚梅; 邓耀波; 孙玉华

    2012-01-01

    can improve the sleep quality an clinical symptoms of patients with insomnia, but the formal treatment has better effect. The mechanism of external counterpulsation for the treatment of insomnia is related with improving the cerebral blood flow of patients.

  4. Lava flows are fractals

    Science.gov (United States)

    Bruno, B. C.; Taylor, G. J.; Rowland, S. K.; Lucey, P. G.; Self, S.

    1992-01-01

    Results are presented of a preliminary investigation of the fractal nature of the plan-view shapes of lava flows in Hawaii (based on field measurements and aerial photographs), as well as in Idaho and the Galapagos Islands (using aerial photographs only). The shapes of the lava flow margins are found to be fractals: lava flow shape is scale-invariant. This observation suggests that nonlinear forces are operating in them because nonlinear systems frequently produce fractals. A'a and pahoehoe flows can be distinguished by their fractal dimensions (D). The majority of the a'a flows measured have D between 1.05 and 1.09, whereas the pahoehoe flows generally have higher D (1.14-1.23). The analysis is extended to other planetary bodies by measuring flows from orbital images of Venus, Mars, and the moon. All are fractal and have D consistent with the range of terrestrial a'a and have D consistent with the range of terrestrial a'a and pahoehoe values.

  5. Use of the RACE technique for quantitative flow measurements

    International Nuclear Information System (INIS)

    A phantom has been designed for measuring flow velocities; using pipes of specified diameter and selectable pulse rates, flow rates varying from 0-250 cm/s can be determined. The measurements are made in a superconductive magnet with a field strength of 1.5 Tesla, employing a RACE technique. The reference technique was electromagnetic flow measurement. There was good linear correlation between the electromagnetic and the MRT results with a correlation coefficient of 0.98. It is necessary in the first place to estimate flow speed; if flow velocity is unknown initially, there is no correlation. Hence, in everyday use erroneous results may be obtained, particularly since one cannot always demonstrate vessels in all parts of the body without superimposition. Further clinical studies are required in various vascular territories to evaluate the usefulness of the RACE technique for flow measurements. (orig.)

  6. 益气活血解毒法对溃疡性结肠炎血浆血小板活化的临床及实验研究%Clinical study and animal experiment on benefiting vital Qi, activating blood flow and detoxication on plasma platelet activation during ulcerative colitis

    Institute of Scientific and Technical Information of China (English)

    安贺军; 王新月; 于玫; 沈静

    2011-01-01

    [目的]探讨益气活血解毒法对溃疡性结肠炎(UC)血浆血小板活化的影响.[方法]分临床研究及动物实验两部分;临床研究以90例溃疡性结肠炎复发患者按随机数字表法随机分为2组,中药治疗组45例,西药对照组45例.治疗3个月后对完全缓解及有效病例(其中治疗组39例,对照组32例)进行为期6个月的随访.治疗组给予益气活血解毒立法的中药汤剂.对照组给予柳氮磺胺吡啶治疗,并各与20例作正常对照.动物实验用三硝基苯磺酸(TNBS)复制实验性大鼠UC模型,将其随机分为模型组、西药对照组、中药治疗组,并设正常对照组.进行反映血小板活化程度的特异性标志物P-选择素的检测.[结果]临床研究中,治疗前UC患者血浆P-选择素水平明显高于正常健康人(P0.05);停药10d时,中药组明显低于西药组(P<0.05).[结论]以益气活血解毒立法的中药溃结复发方与西药比较,可有效降低血浆P-选择素水平,从而阻抑血小板活化,可能是抗溃结复发作用机制之一.%[Objective]To investigate the influence of benefiting vital QI activating blood flow and detoxication on plasma platelet activation during ulcerative colitis (UC).[Methods]The study included clinical study and animal experiment.In clinical study, 90 cases with recurrent UC were randomly divided into the treatment group (n=45) and the control group (n=45) according to the random table.Three months after treatment, the cases of complete remission and effective cases were followed-up for 6 months (39 cases in treatment group, 32 in control group).The patients of treatment group received medicinal decoction of TCM consisting of herbs with benefiting vital Qi, activating blood flow and detoxication; the control group was treated with salazosulfapyridine.In animal experiment, UC was induced with TNBS in rats and then randomly divided into model control group, western medicine group, the traditional Chinese medicine

  7. 导流杂交检测人乳头状瘤病毒感染与宫颈癌临床分期及病理分型关系%Flow-through hybridization detection of the relationship between HPV infection and cervical cancer clinical staging and pathology typing

    Institute of Scientific and Technical Information of China (English)

    陈文学; 张焜和; 邹学森; 黄秀珍; 陈岳青

    2014-01-01

    目的:分析导流杂交检测人乳头状瘤病毒(H PV )感染与宫颈癌临床分期及病理分型的关系,为其筛查和诊断提供依据。方法使用导流杂交技术对医院2009年3月-2012年7月收治的2176例门诊或住院女性患者,进行HPV检测,对 HPV阳性患者进行宫颈组织病理学诊断,分析导流杂交检测结果与病理学诊断结果的关系,所有数据采用SPSS13.0软件进行统计分析。结果2176例患者中共检出1283例 HPV 阳性,阳性率58.96%,其中1145例细胞学异常,异常率52.61%,细胞学正常患者H PV阳性率明显低于慢性炎症、宫颈上皮内瘤病变(CIN)及宫颈癌患者,差异有统计学意义(P<0.05);宫颈癌患者 HPV阳性率为100.0%,显著高于慢性炎症及CIN患者;1283例HPV阳性患者病理诊断高危率为40.45%,细胞学正常、慢性炎症及CINⅠ患者高危率明显低于CINⅡ、Ⅲ及宫颈癌患者,差异有统计学意义(P<0.05)。结论 HPV感染是导致宫颈癌发生发展的重要因素,HPV阳性率高、高危分型率高,提示患者宫颈癌风险越高,而宫颈癌导流杂交检测具有操作方便、结果直观、判断准确等优势,可有效提高宫颈癌癌前病变的检测效果。%OBJECTIVE To analyze the releationship between HPV infection and cervical cancer clinical staging and pathology typing by using flow-through hybridization detection ,so as to provide the basis for the screening and diagnosis of typing and staging and clinical pathology of cervical cancer . METHODS Using flow-through hybridization technique in our hospital in Mar .2009 to Jul .2012 ,a total of 2176 cases of female outpatients or hospitalization in female patients with HPV were detected in HPV positive patients ,cervical histopathological diagnosis ,analysis of the relationship between the detection results of flow-through hybridization and pathology diagnosis results .SPSS16 .0

  8. Wealth-flow forecasting

    OpenAIRE

    Bradut BOLOS

    2008-01-01

    The Wealth Flow is part of an ABC type approach, and should suggest the wealth either generated (by income recognized in accounting, or not) or consumed (by recognized expenses or not). From the investor’s point of view this should be the next stage of analyze after the cash flow analyze, showing his net benefits generated by an investment. In a final stage the wealth flow should be a sum of shares value growth and dividends, however as the market is not always responding immediately and dire...

  9. Initiation of slug flow

    Energy Technology Data Exchange (ETDEWEB)

    Hanratty, T.J.; Woods, B.D. [Univ. of Illinois, Urbana, IL (United States)

    1995-12-31

    The initiation of slug flow in a horizontal pipe can be predicted either by considering the stability of a slug or by considering the stability of a stratified flow. Measurements of the shedding rate of slugs are used to define necessary conditions for the existence of a slug. Recent results show that slugs develop from an unstable stratified flow through the evolution of small wavelength waves into large wavelength waves that have the possibility of growing to form a slug. The mechanism appears to be quite different for fluids with viscosities close to water than for fluids with large viscosities (20 centipoise).

  10. Bypass Flow Study

    International Nuclear Information System (INIS)

    The purpose of the fluid dynamics experiments in the MIR (Matched Index of-Refraction) flow system at Idaho National Laboratory (INL) is to develop benchmark databases for the assessment of Computational Fluid Dynamics (CFD) solutions of the momentum equations, scalar mixing, and turbulence models for the flow ratios between coolant channels and bypass gaps in the interstitial regions of typical prismatic standard fuel element (SFE) or upper reflector block geometries of typical Modular High-temperature Gas-cooled Reactors (MHTGR) in the limiting case of negligible buoyancy and constant fluid properties. The experiments use Particle Image Velocimetry (PIV) to measure the velocity fields that will populate the bypass flow study database.

  11. Bypass Flow Study

    Energy Technology Data Exchange (ETDEWEB)

    Richard Schultz

    2011-09-01

    The purpose of the fluid dynamics experiments in the MIR (Matched Index of-Refraction) flow system at Idaho National Laboratory (INL) is to develop benchmark databases for the assessment of Computational Fluid Dynamics (CFD) solutions of the momentum equations, scalar mixing, and turbulence models for the flow ratios between coolant channels and bypass gaps in the interstitial regions of typical prismatic standard fuel element (SFE) or upper reflector block geometries of typical Modular High-temperature Gas-cooled Reactors (MHTGR) in the limiting case of negligible buoyancy and constant fluid properties. The experiments use Particle Image Velocimetry (PIV) to measure the velocity fields that will populate the bypass flow study database.

  12. Control of Unstable Flows

    Institute of Scientific and Technical Information of China (English)

    刘曾荣; 茅坚民

    2003-01-01

    Without introducing a discrete model, unstable continuous flows in a neighbourhood of an unstable stationary point can be stabilized. The linear part of the vector field of disturbing the flow can be managed to become the state variable multiplied by a negative constant. The nonlinear part of the vector field keeps to be unchanged,therefore flows far away from the stationary point are almost unaffected by the disturbance. The control method is easy to be used, even for practical problems for which a priori analytical knowledge of system dynamics is unavailable.

  13. Elliptic flow phenomenon at ATLAS

    OpenAIRE

    Spousta, Martin

    2014-01-01

    We summarize measurements of elliptic flow and higher order flow harmonics performed by the ATLAS experiment at the LHC. Results on event-averaged flow measurements and event-plane correlations in Pb+Pb collisions are discussed along with the event-by-event flow measurements. Further, we summarize results on flow in p+Pb collisions.

  14. 4D flow mri post-processing strategies for neuropathologies

    Science.gov (United States)

    Schrauben, Eric Mathew

    4D flow MRI allows for the measurement of a dynamic 3D velocity vector field. Blood flow velocities in large vascular territories can be qualitatively visualized with the added benefit of quantitative probing. Within cranial pathologies theorized to have vascular-based contributions or effects, 4D flow MRI provides a unique platform for comprehensive assessment of hemodynamic parameters. Targeted blood flow derived measurements, such as flow rate, pulsatility, retrograde flow, or wall shear stress may provide insight into the onset or characterization of more complex neuropathologies. Therefore, the thorough assessment of each parameter within the context of a given disease has important medical implications. Not surprisingly, the last decade has seen rapid growth in the use of 4D flow MRI. Data acquisition sequences are available to researchers on all major scanner platforms. However, the use has been limited mostly to small research trials. One major reason that has hindered the more widespread use and application in larger clinical trials is the complexity of the post-processing tasks and the lack of adequate tools for these tasks. Post-processing of 4D flow MRI must be semi-automated, fast, user-independent, robust, and reliably consistent for use in a clinical setting, within large patient studies, or across a multicenter trial. Development of proper post-processing methods coupled with systematic investigation in normal and patient populations pushes 4D flow MRI closer to clinical realization while elucidating potential underlying neuropathological origins. Within this framework, the work in this thesis assesses venous flow reproducibility and internal consistency in a healthy population. A preliminary analysis of venous flow parameters in healthy controls and multiple sclerosis patients is performed in a large study employing 4D flow MRI. These studies are performed in the context of the chronic cerebrospinal venous insufficiency hypothesis. Additionally, a

  15. Refrigeration. Two-Phase Flow. Flow Regimes and Pressure Drop

    DEFF Research Database (Denmark)

    Knudsen, Hans-Jørgen Høgaard

    2002-01-01

    The note gives the basic definitions used in two-phase flow. Flow regimes and flow regimes map are introduced. The different contributions to the pressure drop are stated together with an imperical correlation from the litterature....

  16. Analysis of liposomes using asymmetrical flow field-flow fractionation

    DEFF Research Database (Denmark)

    Kuntsche, Judith; Decker, Christiane; Fahr, Alfred

    2012-01-01

    Liposomes composed of dipalmitoylphosphatidylcholine and dipalmitoylphosphatidylglycerol were analyzed by asymmetrical flow field-flow fractionation coupled with multi-angle laser light scattering. In addition to evaluation of fractionation conditions (flow conditions, sample mass, carrier liquid...

  17. [AGIKO (Clinical Research Fellow); a training model aimed at enhancement of clinical scientific research].

    Science.gov (United States)

    van Rees-Wortelboer, M M; Lamberts, S W; Klasen, E C

    1997-06-21

    The enhancement of clinical scientific research in the Netherlands is being stimulated to a substantial extent by the introduction and stimulation of a training model aimed at the combined training of physicians to both a general practitioner or specialist and a clinical researcher, the AGIKO (Clinical Research Fellow). The model has been recognized by the Central College for Recognition and Registration of Medical Specialists. Extra stimulation by the section Medical Sciences of the Netherlands Organization for Scientific Research (MW-NWO) makes it possible to appoint AGIKOs on second or third flows of funds but also within the first flow of funds. During the last two years, 25 AGIKO applications from ten medical specialisms have been approved. The AGIKO model may help to meet (expected) needs for future clinical-medical research workers in specific research areas. PMID:9380169

  18. Participating in Clinical Trials

    Medline Plus

    Full Text Available ... Participating in Clinical Trials: About Clinical Trials In This Topic About Clinical Trials Risks and Benefits Terms ... with Your Doctor Taking Medicines The information in this topic was provided by the National Library of ...

  19. Participating in Clinical Trials

    Medline Plus

    Full Text Available ... Participating in Clinical Trials About Clinical Trials A Research Study With Human Subjects A clinical trial is a research study that involves human subjects. The purpose of ...

  20. Participating in Clinical Trials

    Medline Plus

    Full Text Available ... Clinical Trials In This Topic About Clinical Trials Risks and Benefits Terms to Know Finding a Clinical ... researchers may gather information about experimental treatments, their risks, and how well they work compare existing therapies ...

  1. Participating in Clinical Trials

    Medline Plus

    Full Text Available Home > Health topics A-Z > Participating in Clinical Trials: About Clinical Trials In This Topic About Clinical Trials Risks ... centers across the country. The National Institutes of Health funds much of this basic research. Screening Trials ...

  2. Participating in Clinical Trials

    Medline Plus

    Full Text Available ... on. Participating in Clinical Trials About Clinical Trials A Research Study With Human Subjects A clinical trial is a research study that involves human subjects. The purpose ...

  3. 子宫动脉胎儿脐动脉血流变化对胎儿生长受限的临床意义%Clinical significance on fetal umbilical artery blood flow changes of uterine artery for the fetal growth restriction

    Institute of Scientific and Technical Information of China (English)

    徐金毛; 陈桃英; 郑洪平; 林李梅

    2011-01-01

    目的:探讨子宫动脉胎儿脐动脉血流变化对胎儿生长受限的临床意义.方法:回顾性分析我院2007年1月~2010年5月收治入院的胎儿生长受限患者200例的临床资料.结果:观察组产妇子宫动脉脐动脉血流速度峰谷比(S/D)值为(2.70±1.26),对照组为(1.76±0.35);胎儿脐动脉S/D值分别为(2.39±0.38)和(2.85±0.61),两组比较,差异均有统计学意义(均P0.05).5例死亡病例产前胎儿脐血流检查S/D值升高,平均为(4.8±1.6).说明彩色多普勒测量子宫动脉及胎儿脐动脉检查是评估胎儿疾病严重程度的最佳指标.结论:彩色多普勒测量子宫动脉及胎儿脐动脉检查可以作为胎儿生长受限的常规监测措施,了解治疗效果,确定分娩时机.肝素对于治疗胎儿生长受限效果显著,可作为临床首选药.%Objective: To observe the clinical significance on fetal umbilical artery blood flow changes of uterine artery for the fetal growth restriction. Methods: The clinical data of 200 patients of fetal growth restriction in our hospital from January 2007 to May 2010 were retrospectively analyzed. Results: In the observation group, the maternal uterine artery S/D was (2.70±1.26) and was (1.76±0.35) in the control group; fetal umbilical artery S/D was (2.39±0.38) and (2.85±0.61) respectively, the difference between the two groups was significant (P<0.01). The observation group treated with heparin after the baby was born two courses per week on average biparietal diameter, femur length, head circumference, abdominal circumference growth and Apgar score, body weight compared with the control group the situation was no significant difference (P>0.05). 5 fatal cases of prenatal umbilical check S/D ratio increased with an average of (4.8±1.6). That color Doppler measurement of uterine artery and fetal umbilical artery examination was to assess the fetus the best indicator of disease severity. Conclusion: Color Doppler measurement of uterine

  4. Multicomponent flow modeling

    Institute of Scientific and Technical Information of China (English)

    GIOVANGIGLI; Vincent

    2012-01-01

    We present multicomponent flow models derived from the kinetic theory of gases and investigate the symmetric hyperbolic-parabolic structure of the resulting system of partial differential equations.We address the Cauchy problem for smooth solutions as well as the existence of deflagration waves,also termed anchored waves.We further discuss related models which have a similar hyperbolic-parabolic structure,notably the SaintVenant system with a temperature equation as well as the equations governing chemical equilibrium flows.We next investigate multicomponent ionized and magnetized flow models with anisotropic transport fluxes which have a different mathematical structure.We finally discuss numerical algorithms specifically devoted to complex chemistry flows,in particular the evaluation of multicomponent transport properties,as well as the impact of multicomponent transport.

  5. Complex Flow Workshop Report

    Energy Technology Data Exchange (ETDEWEB)

    none,

    2012-05-01

    This report documents findings from a workshop on the impacts of complex wind flows in and out of wind turbine environments, the research needs, and the challenges of meteorological and engineering modeling at regional, wind plant, and wind turbine scales.

  6. Reversed extension flow

    DEFF Research Database (Denmark)

    Nielsen, Jens Kromann; Rasmussen, Henrik K.

    2008-01-01

    Afilament stretching rheometer (FSR) was used for measuring the start-up of uni-axial elongational flow followed by reversed bi-axial flow, both with a constant elongational rate. A narrow molecular mass distribution linear polystyrene with a molecular weight of 145 kg / mole wis subjected...... to the start-up of elongation for three Hencky strain units and subsequently the reversed flow. The integral molecular stress function formulation within the 'interchain pressure' concept agrees with the experiments. In the experiments the Hencky strain at which the str~ss becomes zero (the recovery strain......) in the reversed flow has been identified. The recovery strain is found to increase with elongational rate, and has a maximum value of approximately 1.45. The Doi Edwards model using any stretch evolution equation is not able to predict the correct level of the recovery strain....

  7. Flow in data racks

    Directory of Open Access Journals (Sweden)

    Manoch Lukáš

    2014-03-01

    Full Text Available This paper deals with the flow in data racks. The aim of this work is to find a new arrangement of elements regulating the flow in the data rack so that the aerodynamic losses and the recirculation zones were minimized. The main reason for solving this problem is to reduce the costs of data racks cooling. Another problem to be solved is a reverse flow in the servers, thus not cooled, occuring due to the underpressure in the recirculation zones. In order to solve the problem, the experimental and numerical model of 27U data rack fitted with 10 pieces of server models with a total input of 10 kW was created. Different configurations of layout of elements affecting the flow in the inlet area of the data rack were compared. Depending on the results achieved, design solutions for the improvement of existing solutions were adopted and verified by numerical simulations.

  8. Flow Cytometry Section

    Data.gov (United States)

    Federal Laboratory Consortium — The primary goal of the Flow Cytometry Section is to provide the services of state-of-the-art multi-parameter cellular analysis and cell sorting for researchers and...

  9. Shocklets in compressible flows

    Institute of Scientific and Technical Information of China (English)

    袁湘江; 男俊武; 沈清; 李筠

    2013-01-01

    The mechanism of shocklets is studied theoretically and numerically for the stationary fluid, uniform compressible flow, and boundary layer flow. The conditions that trigger shock waves for sound wave, weak discontinuity, and Tollmien-Schlichting (T-S) wave in compressible flows are investigated. The relations between the three types of waves and shocklets are further analyzed and discussed. Different stages of the shocklet formation process are simulated. The results show that the three waves in compressible flows will transfer to shocklets only when the initial disturbance amplitudes are greater than the certain threshold values. In compressible boundary layers, the shocklets evolved from T-S wave exist only in a finite region near the surface instead of the whole wavefront.

  10. RG flows and instantons

    International Nuclear Information System (INIS)

    In these two lectures I discuss RG flow solutions in (1,0) six dimensional supergravity involving SU(2) Yang-Mills instantons. in the conformally flat part of the 6D metric. The solutions interpolate between two (4,0) supersymmetric AdS3×S3 backgrounds with different values of AdS3 and S3 radii and describe RG flows in the dual 2D SCFT. The flows described are of v.e.v. type, driven by a vacuum expectation value of a (not exactly) marginal operator of dimension 2 in the UV. We give an interpretation of the supergravity solution in terms of the D1/D5 system in type I string theory on K3, whose effective field theory is expected to flow to a (4,0) SCFT in the infrared.

  11. Hovering in Oscillatory Flows

    CERN Document Server

    Huang, Yangyang; Kanso, Eva

    2015-01-01

    We investigate the hovering dynamics of rigid bodies with up-down asymmetry placed in oscillating background flows. Recent experiments on inanimate pyramid-shaped objects in oscillating flows with zero mean component demonstrate that the resulting aerodynamic forces are sufficient to keep the object aloft. The mechanisms responsible for this lift production are fundamentally unsteady and depend on the shed vorticity. Here, we consider a model system of a two-dimensional flyer and compute the unsteady, two-way coupling between the flyer and the surrounding fluid in the context of the vortex sheet model. We examine in detail the flow properties (frequency and speed) required for hovering and their dependence on the flyer's characteristics (mass and geometry). We find that the aerodynamic effort required to hover is an intrinsic property of the flyer itself: a given flyer requires a constant amount of effort to hover, irrespective of the frequency and speed of the oscillating flow. This physical insight will pot...

  12. Flow cytometry bioinformatics.

    Directory of Open Access Journals (Sweden)

    Kieran O'Neill

    Full Text Available Flow cytometry bioinformatics is the application of bioinformatics to flow cytometry data, which involves storing, retrieving, organizing, and analyzing flow cytometry data using extensive computational resources and tools. Flow cytometry bioinformatics requires extensive use of and contributes to the development of techniques from computational statistics and machine learning. Flow cytometry and related methods allow the quantification of multiple independent biomarkers on large numbers of single cells. The rapid growth in the multidimensionality and throughput of flow cytometry data, particularly in the 2000s, has led to the creation of a variety of computational analysis methods, data standards, and public databases for the sharing of results. Computational methods exist to assist in the preprocessing of flow cytometry data, identifying cell populations within it, matching those cell populations across samples, and performing diagnosis and discovery using the results of previous steps. For preprocessing, this includes compensating for spectral overlap, transforming data onto scales conducive to visualization and analysis, assessing data for quality, and normalizing data across samples and experiments. For population identification, tools are available to aid traditional manual identification of populations in two-dimensional scatter plots (gating, to use dimensionality reduction to aid gating, and to find populations automatically in higher dimensional space in a variety of ways. It is also possible to characterize data in more comprehensive ways, such as the density-guided binary space partitioning technique known as probability binning, or by combinatorial gating. Finally, diagnosis using flow cytometry data can be aided by supervised learning techniques, and discovery of new cell types of biological importance by high-throughput statistical methods, as part of pipelines incorporating all of the aforementioned methods. Open standards, data

  13. Optimal Flow Control Design

    Science.gov (United States)

    Allan, Brian; Owens, Lewis

    2010-01-01

    In support of the Blended-Wing-Body aircraft concept, a new flow control hybrid vane/jet design has been developed for use in a boundary-layer-ingesting (BLI) offset inlet in transonic flows. This inlet flow control is designed to minimize the engine fan-face distortion levels and the first five Fourier harmonic half amplitudes while maximizing the inlet pressure recovery. This concept represents a potentially enabling technology for quieter and more environmentally friendly transport aircraft. An optimum vane design was found by minimizing the engine fan-face distortion, DC60, and the first five Fourier harmonic half amplitudes, while maximizing the total pressure recovery. The optimal vane design was then used in a BLI inlet wind tunnel experiment at NASA Langley's 0.3-meter transonic cryogenic tunnel. The experimental results demonstrated an 80-percent decrease in DPCPavg, the reduction in the circumferential distortion levels, at an inlet mass flow rate corresponding to the middle of the operational range at the cruise condition. Even though the vanes were designed at a single inlet mass flow rate, they performed very well over the entire inlet mass flow range tested in the wind tunnel experiment with the addition of a small amount of jet flow control. While the circumferential distortion was decreased, the radial distortion on the outer rings at the aerodynamic interface plane (AIP) increased. This was a result of the large boundary layer being distributed from the bottom of the AIP in the baseline case to the outer edges of the AIP when using the vortex generator (VG) vane flow control. Experimental results, as already mentioned, showed an 80-percent reduction of DPCPavg, the circumferential distortion level at the engine fan-face. The hybrid approach leverages strengths of vane and jet flow control devices, increasing inlet performance over a broader operational range with significant reduction in mass flow requirements. Minimal distortion level requirements

  14. Reactivity to low‐flow as a potential determinant for brachial artery flow‐mediated vasodilatation

    OpenAIRE

    Aizawa, Kunihiko; Elyas, Salim; Adingupu, Damilola D.; Casanova, Francesco; Gooding, Kim M.; Strain, W. David; Shore, Angela C.; Gates, Phillip E.

    2016-01-01

    Abstract Previous studies have reported a vasoconstrictor response in the radial artery during a cuff‐induced low‐flow condition, but a similar low‐flow condition in the brachial artery results in nonuniform reactivity. This variable reactivity to low‐flow influences the subsequent flow‐mediated dilatation (FMD) response following cuff‐release. However, it is uncertain whether reactivity to low‐flow is important in data interpretation in clinical populations and older adults. This study aimed...

  15. Traffic Flow Theory

    OpenAIRE

    Maerivoet, Sven; De Moor, Bart

    2005-01-01

    The scientific field of traffic engineering encompasses a rich set of mathematical techniques, as well as researchers with entirely different backgrounds. This paper provides an overview of what is currently the state-of-the-art with respect to traffic flow theory. Starting with a brief history, we introduce the microscopic and macroscopic characteristics of vehicular traffic flows. Moving on, we review some performance indicators that allow us to assess the quality of traffic operations. A f...

  16. Fundamentals of Multiphase Flow

    OpenAIRE

    Brennen, Christopher Earls

    2005-01-01

    The subject of multiphase flows encompasses a vast field, a host of different technological contexts, a wide spectrum of different scales, a broad range of engineering disciplines and a multitude of different analytical approaches. Not surprisingly, the number of books dealing with the subject is voluminous. For the student or researcher in the field of multiphase flow this broad spectrum presents a problem for the experimental or analytical methodologies that might be appro...

  17. Flow assurance study

    OpenAIRE

    Böser, W.; Belfroid, S.P.C.

    2013-01-01

    Generally large scale carbon capture projects require pipeline systems for the transporting of the CO2 from its point of capture to the storage site. The article will give information on the proposed operational management system. This has to work for all process situations, ranging from steady flow at varying injection conditions and flow rates, to start-up and shutdown procedures and also for emergency shutdown at the platform. In all these operational situations the phase behaviour of CO2 ...

  18. Information Flow Testing

    OpenAIRE

    Le Guernic, Gurvan

    2007-01-01

    Noninterference, which is an information flow property, is typically used as a baseline security policy to formalize confidentiality of secret information manipulated by a program. Noninterference verification mechanisms are usually based on static analyses and, to a lesser extent, on dynamic analyses. In contrast to those works, this paper proposes an information flow testing mechanism. This mechanism is sound from the point of view of noninterference. It is based on standard testing techniq...

  19. Traffic-flow simulation

    OpenAIRE

    OMAHEN, ANDRAŽ

    2015-01-01

    This diploma thesis presents the behavior of program, which uses the traffic light enhanced transport network to simulate the traffic flow of vehicles that behave according to the IDM model. We upgraded the program to allow, for the given network, to optimize the traffic flow. Because of the overwhelming problem of road closures or their rearrangement, we added a graphical user interface with which a user can create or modify the road network to observe changes in traffic. The objective of...

  20. Nonlinearity in groundwater flow

    OpenAIRE

    Barends, F.B.J.

    1980-01-01

    Since 1856 when Darcy laid the basis for the calculation of the flow of water through sands, researchers have been interested in groundwater flow. Groundwater is essential for agriculture and water supply, but it also plays an important role when soil is used as a construction element, such as for dykes, roads and foundations. The mechanical behaviour of saturated or dry, fine graded or coarse soils are quite different. The theory of groundwater mechanics must be based on the system: water-so...

  1. Electrochemical flow capacitors

    Science.gov (United States)

    Gogotsi, Yury; Presser, Volker; Kumbur, Emin Caglan

    2015-10-27

    The present invention generally relates to devices for energy storage technologies, and more particularly to electrochemical flow capacitor systems and applications. In some aspects, these flow capacitors have at least one electrode comprising a non-stationary solid or semi-solid composition comprising supercapacitive particles and an electrolytic solvent in electrical communication with at least one current collector, and energy is stored and/or released by charging and/or discharging the electrode(s).

  2. Ozone flow visualization techniques

    Science.gov (United States)

    Dickerson, R. R.; Stedman, D. H.

    1981-01-01

    Flow visualization techniques using ozone for tracing gas flows are proposed whereby ozone is detected through its strong absorption of ultraviolet light, which is easily made visible with fluorescent materials, or through its reaction with nitric oxide to form excited nitrogen dioxide, which in relaxing emits detectable light. It is shown that response speeds in the kHz range are possible with an ultraviolet detection system for initial ozone concentrations of about 1%.

  3. Stability of parallel flows

    CERN Document Server

    Betchov, R

    2012-01-01

    Stability of Parallel Flows provides information pertinent to hydrodynamical stability. This book explores the stability problems that occur in various fields, including electronics, mechanics, oceanography, administration, economics, as well as naval and aeronautical engineering. Organized into two parts encompassing 10 chapters, this book starts with an overview of the general equations of a two-dimensional incompressible flow. This text then explores the stability of a laminar boundary layer and presents the equation of the inviscid approximation. Other chapters present the general equation

  4. Flow on sweeping networks

    OpenAIRE

    Degond, Pierre; Herty, Michael; Liu, Jian-guo

    2013-01-01

    We introduce a cellular automaton model coupled with a transport equation for flows on graphs. The direction of the flow is described by a switching process where the switching probability dynamically changes according to the value of the transported quantity in the neighboring cells. A motivation is pedestrian dynamics in a small corridor where the propagation of people in a part of the corridor can be either left or rightgoing. Under the assumptions of propagation of chaos and mean-field li...

  5. Blood Flow Multiscale Phenomena

    OpenAIRE

    Agić, Ante; Mijović, Budimir; Nikolić, Tatjana

    2007-01-01

    The cardiovascular disease is one of most frequent cause deaths in modern society. The objective of this work is analyse the effect of dynamic vascular geometry (curvature, torsion,bifurcation) and pulsatile blood nature on secondary flow, wall shear stress and platelet deposition. The problem was examined as multi-scale physical phenomena using perturbation analysis and numerical modelling. The secondary flow determined as influence pulsatile pressure, vascular tube time-dependen...

  6. Future requirements. Clinical investigations

    DEFF Research Database (Denmark)

    Qvist, V.

    2002-01-01

    Biocompatability, Cariology, Clinical trials, Dental materials, Helath services research, Human, Pedodontics......Biocompatability, Cariology, Clinical trials, Dental materials, Helath services research, Human, Pedodontics...

  7. Yamabe flow on Berwald manifolds

    Science.gov (United States)

    Azami, Shahroud; Razavi, Asadollah

    2015-12-01

    Studying the geometric flow plays a powerful role in mathematics and physics. We introduce the Yamabe flow on Finsler manifolds and we will prove the existence and uniqueness for solution of Yamabe flow on Berwald manifolds.

  8. Fanno Flow in Microchannels

    Directory of Open Access Journals (Sweden)

    M.A. Al-Nimr

    2012-12-01

    Full Text Available In this study, the Fanno flow problem has been theoretically investigated using both, first order and second order velocity-slip boundary conditions models and then compared to the no-slip boundary conditions solution. The objective is to study the behavior of the flow predicted by the two slip models. Then, an attempt will be made to establish criteria for using the no-slip and the two velocity-slip models. The Fanno flow is an ideal gas adiabatic flow in constant area duct with friction. It is found that the velocity profile for the two velocity-slip models has the same shape as the no-slip model velocity profile but with an amount of slip at the wall which increases as the Knudsen number, Kn, increases. Also the effect of the slip has on the compressible flow characteristics have been examined. It shows that as the Kn increases, the skin friction coefficient Cf and the Darcy friction coefficient f decrease. Overall, it is concluded that for an adiabatic compressible flow in circular microchannel, for Kn≤0.01 there is no need to apply any velocity-slip model as the no-slip model gives sufficiently accurate predictions. As for the range 0.01≤Kn≤0.1, the first order velocity slip model should be applied and so for this range, there is no necessity to use the second order velocity-slip model.

  9. A Cryogenic Flow Sensor Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Advanced Technologies Group, Inc. proposes the development of a Cryogenic Flow Sensor (CFS) for determining mass flow of cryogens in spacecraft propellant...

  10. Simulation of blood flow in a small-diameter vascular graft model with a swirl (spiral) flow guider

    Institute of Scientific and Technical Information of China (English)

    Robert; GUIDOIN

    2008-01-01

    Small-diameter vascular grafts are in large demand for coronary and peripheral bypass procedures, but present products still fail in long-term clinical application. In the present communication, a new type of small-diameter graft with a swirl flow guider was proposed to improve graft patency rate. Flow pattern in the graft was simulated numerically and compared with that in a conventional graft. The numerical results revealed that the swirl flow guider could indeed make the blood flow rotate in the new graft. The swirling flow distal to the flow guider significantly altered the flow pattern in the new graft and the ve- locity profiles were re-distributed. Due to the swirling flow, the blood velocity near the vessel wall and wall shear rate were greatly enhanced. We believe that the increased blood velocity near the wall and the wall shear rate can impede the occurrence of acute thrombus formation and intimal hyperplasia, hence can improve the graft patency rate for long-term clinical use.

  11. Physics of Zonal Flows

    Science.gov (United States)

    Itoh, Kimitaka

    2005-10-01

    This talk describes an overview of zonal flow physics, covering the theory, simulation and experiment. The zonal flows are excited nonlinearly by drift wave fluctuations, and suppress the turbulence and transport, so as to realize a self-regulating state for turbulence and mesoscale structure. This recognition is the central of recent paradigm shift in plasma physics, i.e., the preceding linear, local and deterministic pictures of instability and transport have been taken over by the new nonlinear, nonlocal (in real and wavenumber spaces) and statistical pictures of them. The zonal flow phenomenon, i.e., the global axial vector fields are generated by the release of global free energy in scalar fields through exciting turbulence, is a typical example of the fundamental issues in modern physics. In this review, the progresses made by theory and simulations, such as the linear damping rate, nonlinear mechanisms for growth and saturation, law of energy partition between turbulence and flow, life time of zonal flow, and so on, are explained. The transport by drift wave fluctuations, which are dressed by zonal flows, is discussed. Then experimental observations and verifications, which have been piled up rapidly in basic plasma experiments and confinement research, are explained, highlighting the integration with theory and simulation. Generalization to include magnetic field (zonal field) is addressed, in the light of the study of dynamo. Zonal flows in both laboratory and planetary-solar circumstances are discussed as well. This presentation illustrates the fast evolution of the physics of turbulence and structure formation of plasmas in the nature and laboratory. In collaboration with S.-I. Itoh, P. H. Diamond, T. S. Hahm, A. Fujisawa, G. R. Tynan and M. Yagi.

  12. Oscillatory flow chemical reactors

    Directory of Open Access Journals (Sweden)

    Slavnić Danijela S.

    2014-01-01

    Full Text Available Global market competition, increase in energy and other production costs, demands for high quality products and reduction of waste are forcing pharmaceutical, fine chemicals and biochemical industries, to search for radical solutions. One of the most effective ways to improve the overall production (cost reduction and better control of reactions is a transition from batch to continuous processes. However, the reactions of interests for the mentioned industry sectors are often slow, thus continuous tubular reactors would be impractically long for flow regimes which provide sufficient heat and mass transfer and narrow residence time distribution. The oscillatory flow reactors (OFR are newer type of tube reactors which can offer solution by providing continuous operation with approximately plug flow pattern, low shear stress rates and enhanced mass and heat transfer. These benefits are the result of very good mixing in OFR achieved by vortex generation. OFR consists of cylindrical tube containing equally spaced orifice baffles. Fluid oscillations are superimposed on a net (laminar flow. Eddies are generated when oscillating fluid collides with baffles and passes through orifices. Generation and propagation of vortices create uniform mixing in each reactor cavity (between baffles, providing an overall flow pattern which is close to plug flow. Oscillations can be created by direct action of a piston or a diaphragm on fluid (or alternatively on baffles. This article provides an overview of oscillatory flow reactor technology, its operating principles and basic design and scale - up characteristics. Further, the article reviews the key research findings in heat and mass transfer, shear stress, residence time distribution in OFR, presenting their advantages over the conventional reactors. Finally, relevant process intensification examples from pharmaceutical, polymer and biofuels industries are presented.

  13. Through flow analysis within axial flow turbomachinery blade rows

    Science.gov (United States)

    Girigoswami, H.

    1986-09-01

    Using Katsanis' Through Flow Code, inviscid flow through an axial flow compressor rotor blade as well as flow through inlet guide vanes are analyzed and the computed parameters such as meridional velocity distribution, axial velocity distribution along radial lines, and velocity distribution over blade surfaces are presented.

  14. Clinical value of color Doppler ultrasound detection of blood flow parameters and vascular diameter in carot-id artery and vertebral artery%彩色多普勒超声检测颈动脉及椎动脉血流参数和血管内径的临床价值

    Institute of Scientific and Technical Information of China (English)

    刘天宇; 刘艳伟; 郑利; 礼宁; 李丽

    2014-01-01

    Objective To investigate the effect and clinical value of color Doppler ultrasound detection of blood flow parameters and vascular diameter in carotid artery and vertebral artery.Methods 150 healthcases were collected as the study objects.According to the age and gender differences, making a detailed classification, color Doppler ultrasound was used to detected the internal carotid artery, vertebral artery and the carotid artery.Results As age grows,the blood flow velocity decreases,and the pulsatility index( PI) and resistance index( RI) has no obvi-ous relation with age;There were positive correlation between the diameter of the carotid artery and vertebral artery and age( P<0.05) ,and the male population the diameter of the carotid artery was significantly wider than that of the female population(P<0.05),left vertebral artery diameter was significantly wider than that of the right side(P<0.05).Conclusion Color Doppler ultrasound detection can let us get detailed carotid and vertebral artery anatomy and blood supply of information,which is good to diagnosis cerebrovascular disease.%目的:探讨彩色多普勒超声检测颈动脉、椎动脉血流参数和血管内径的有效性及其临床价值。方法募集150例健康者作为研究对象,按年龄与性别的不同,做详细的分类,对其颈总动脉、颈内动脉及椎动脉行超声多普勒超声检测。结果(1)20~39岁人群颈动脉动脉收缩期流速为(64.18±12.51)cm/s,明显高于>39~59岁人群的(52.08±11.59)cm/s(t=4.996,P<0.05),而搏动指数(PI)与阻力指数(RI)则与年龄无明显的关系;(2)20~39岁人群颈总动脉内径平均为(6.11±0.66) mm,而>39~59岁人群为(6.59±0.71)mm,差异有统计学意义(t=-3.413,P<0.05),男性人群颈动脉内径明显宽于女性人群(t=2.829,P<0.05),左侧椎动脉内径明显宽于右侧(t=3.481,P<0.05

  15. Piezoelectric axial flow microvalve

    Science.gov (United States)

    Gemmen, Randall; Thornton, Jimmy; Vipperman, Jeffrey S.; Clark, William W.

    2007-01-09

    This invention is directed to a fuel cell operable with a quantity of fuel and a quantity of an oxidizer to produce electrical power, the fuel cell including a fuel cell body including a labyrinth system structured to permit the fuel and the oxidizer to flow therethrough; at least a first catalyst in fluid communication with the labyrinth; and at least a first microvalve operably disposed within at least a portion of the labyrinth. The microvalve utilizes a deflectable member operable upon the application of a voltage from a voltage source. The microvalve includes an elongated flow channel formed therein and extending substantially longitudinally between the first and second ends to permit substantially longitudinal flow of the fluid therethrough and between the first and second ends; and the deflectable member disposed on the valve body, the deflectable member including at least a first piezoelectric portion that is piezoelectrically operable to deflect the deflectable member between an open position and a closed position upon the application of a voltage, the deflectable member in the closed position being operable to resist the flow of the fluid through the flow channel.

  16. Upscaling of Forchheimer flows

    KAUST Repository

    Aulisa, Eugenio

    2014-08-01

    In this work we propose upscaling method for nonlinear Forchheimer flow in heterogeneous porous media. The generalized Forchheimer law is considered for incompressible and slightly-compressible single-phase flows. We use recently developed analytical results (Aulisa et al., 2009) [1] and formulate the resulting system in terms of a degenerate nonlinear flow equation for the pressure with the nonlinearity depending on the pressure gradient. The coarse scale parameters for the steady state problem are determined so that the volumetric average of velocity of the flow in the domain on fine scale and on coarse scale are close. A flow-based coarsening approach is used, where the equivalent permeability tensor is first evaluated following streamline methods for linear cases, and modified in order to take into account the nonlinear effects. Compared to previous works (Garibotti and Peszynska, 2009) [2], (Durlofsky and Karimi-Fard) [3], this approach can be combined with rigorous mathematical upscaling theory for monotone operators, (Efendiev et al., 2004) [4], using our recent theoretical results (Aulisa et al., 2009) [1]. The developed upscaling algorithm for nonlinear steady state problems is effectively used for variety of heterogeneities in the domain of computation. Direct numerical computations for average velocity and productivity index justify the usage of the coarse scale parameters obtained for the special steady state case in the fully transient problem. For nonlinear case analytical upscaling formulas in stratified domain are obtained. Numerical results were compared to these analytical formulas and proved to be highly accurate. © 2014.

  17. Relationship between clinical pathophysiology and pulmonary pathology in patients with congenital heart defects and decreased pulmonary artery blood flow%肺血少型先天性心脏病肺血管病理变化及临床病理生理关系

    Institute of Scientific and Technical Information of China (English)

    许耀强; 刘迎龙; 阮英茆; 吕小东; 于存涛; 李莉

    2008-01-01

    Objective To investigate the relationship between pulmonary pathological features and clinical physiology of congenital heart defects (CHD) with decreased pulmonary artery blood flow.Methods Between July 2001 and May 2006,18 patients with CHD with decreased pulmonary artery blood flow undergoing palliative or definitive repair and having lung biopsy intraoperatively were enrolled in this study.The patients'age was 0.4-8.0 years,and body weight was 6.0-20.0 kg.The method of semi-quantitative morphometric technique and an image analyzer were applied to measure the following indices of pulmonary microveszels:the percentage of media thickness (MT%),the percentage of media section area(MS%) and numbers of microvessels per square centimeter (VPSC).The diameters of left pulmonary artery (LPA) and right pulmonary artery (RPA)were measured with two-dimensional echocardiography.The percutaneous oxygen saturation (SpO2),hemoglobin concentration (HB) and hematocrit value (HCT) were examined and recorded preoperatively.Results There was a significant negative correlation between SpO2 and HCT or lib (R2=0.4914,P=0.001 and R2=0.5505,P <0.001),the variation trend of these three variables was linked.There was a negative correlation between SpO2 and the body weight (R2=0.2208,P=0.049),which is in accordance with clinical features of aggravated process of cyanosis and hypoxia.The morphological observation of lung biopsy specimens indicated that most of peripheral pulmonary arteries were distended,irregular and their walls were uneven,and "lake" type of pulmonary AV malformations were observed.There was a positive correlation between VPSC and the body weight or BSA (R2=0.5472,P <0.001 and R2=0.5233,P=0.001).There was a significant correlation between VPSC and LPA or RPA (R2=0.4312,P=0.003 and R2=0.2463,P=0.036).It was shown that the diameter of central pulmonary arteries could be a reflection of peripheral pulmonary artery growth.The diameter of LPA also correlated with the

  18. Recommendations for quality assurance in multiparametric flow cytometry: first consensus of the Brazilian Group of Flow Cytometry (GBCFLUX)

    OpenAIRE

    Rodolfo P. Correia; Ana Carolina A. Bortolucci; Annelise C. W. Lopes; Alex F. Sandes; Ana Paula de Azambuja; Marta A. Viana; Maria M. Sales; Mihoko Yamamoto; Nydia S. Bacal

    2015-01-01

    ABSTRACT The Brazilian Group of Flow Cytometry (Grupo Brasileiro de Citometria de Fluxo [GBCFLUX]), founded on April 24, 2010, is composed of experts in flow cytometry (FC) area who have the common objective of contributing to technical and scientific advances in Brazilian clinical and research laboratories. Among GBCFLUX working groups, the Quality Control (QC) subcommittee is responsible for discussing data in the literature and contributes to the quality assurance of the pre-analytical, an...

  19. Computational simulations of flow dynamics and blood damage through a bileaflet mechanical heart valve scaled to pediatric size and flow.

    Science.gov (United States)

    Yun, B Min; McElhinney, Doff B; Arjunon, Shiva; Mirabella, Lucia; Aidun, Cyrus K; Yoganathan, Ajit P

    2014-09-22

    Despite pressing needs, there are currently no FDA approved prosthetic valves available for use in the pediatric population. This study is performed for predictive assessment of blood damage in bileaflet mechanical heart valves (BMHVs) with pediatric sizing and flow conditions. A model of an adult-sized 23 mm St. Jude Medical (SJM) Regent(™) valve is selected for use in simulations, which is scaled in size for a 5-year old child and 6-month old infant. A previously validated lattice-Boltzmann method (LBM) is used to simulate pulsatile flow with thousands of suspended platelets for cases of adult, child, and infant BMHV flows. Adult BMHV flows demonstrate more disorganized small-scale flow features, but pediatric flows are associated with higher fluid shear stresses. Platelet damage in the pediatric cases is higher than in adult flow, highlighting thrombus complication dangers of pediatric BMHV flows. This does not necessarily suggest clinically important differences in thromboembolic potential. Highly damaged platelets in pediatric flows are primarily found far downstream of the valve, as there is less flow recirculation in pediatric flows. In addition, damage levels are well below expected thresholds for platelet activation. The extent of differences here documented between the pediatric and adult cases is of concern, demanding particular attention when pediatric valves are designed and manufactured. However, the differences between the pediatric and adult cases are not such that development of pediatric sized valves is untenable. This study may push for eventual approval of prosthetic valves resized for the pediatric population. Further studies will be necessary to determine the validity and potential thrombotic and clinical implications of these findings. PMID:25011622

  20. The clinical value of color doppler flow imaging in diagonosis of perforating venous insufficiency of the lower extremity%彩色多普勒超声诊断下肢交通支静脉功能不全的临床价值

    Institute of Scientific and Technical Information of China (English)

    周晗; 吴庆华; 陈忠; 唐小斌; 杨培; 张煜亚

    2011-01-01

    Objective;To investigate the clinical value of color Doppler flow imaging (CDFI) in di-agonosis of perforating venous insufficiency of the lower extremity. Methods; The clinical data of 64 cases(82 limbs) undergoing high ligation and striping of great saphenous vein and perforator surgery were reviewed retrospectively. The dilated and insufficient perforating venous were diagnosed and located by CDFI. The results were compared with surgery. Results;Total consistent rate, sensitivity,specificity, omission diagonostic rate, mistake diagnostic rate, Youden index,Odd product, positive predictive value, negative predictive value, and Kappa of CDFI in diagnosis of perforating venous insufficiency of the lower extremity was respectively 93. 8% , 96. 5% ,88. 2% ,3.5% , 11. 8% ,0. 837,206.5,98.8% ,71.4% and 0.766 ( P < 0.0001). The CDFI foundings were consistent with operation results very well. Conclusion; CDFI is a useful technique for the diagnosis and locating the dilated and insufficient perforating venous correctly and provide important basis for the operation.%目的:研究彩色多普勒超声诊断下肢交通支静脉功能不全的临床价值.方法:回顾性分析行大隐静脉高位结扎加剥脱术、交通支静脉离断术的64例患者(82条肢体)的临床资料.术前应用彩色多普勒超声检出功能不全的交通支静脉并将其定位,与手术结果相对比.结果:与手术结果相比,彩色多普勒超声诊断准确率、敏感性、特异性、漏诊率、误诊率、约登指数、比数积、阳性预测值、阴性预测值及Kappa值为分别是95.8%、96.5%、88.2%、3.5%、11.8%、0.837、206.5、98.8%、71.4%及1.766.由于彩色多普勒超声的Kappa值为0.766 >0.75,且(P<0.0001),说明其与手术结果非常吻合.结论:彩色多普勒超声能够准确诊断并定位功能不全的交通支静脉,为诊断和治疗提供重要的依据,具有很高的临床价值.

  1. Gaseous Flows in Galaxies

    CERN Document Server

    Combes, F

    2007-01-01

    The gas component plays a major role in the dynamics of spiral galaxies, because of its dissipative character, and its ability to exchange angular momentum with stars in the disk. Due to its small velocity dispersion, it triggers gravitational instabilities, and the corresponding non-axisymmetric patterns produce gravity torques, which mediate these angular momentum exchanges. When a srong bar pattern develops with the same pattern speed all over the disk, only gas inside corotation can flow towards the center. But strong bars are not long lived in presence of gas, and multiple-speed spiral patterns can develop between bar phases, and help the galaxy to accrete external gas flowing from cosmic filaments. The gas is then intermittently driven to the galaxy center, to form nuclear starbursts and fuel an active nucleus. The various time-scales of these gaseous flows are described.

  2. Flow Based Algorithm

    Directory of Open Access Journals (Sweden)

    T. Karpagam

    2012-01-01

    Full Text Available Problem statement: Network topology design problems find application in several real life scenario. Approach: Most designs in the past either optimize for a single criterion like shortest or cost minimization or maximum flow. Results: This study discussed about solving a multi objective network topology design problem for a realistic traffic model specifically in the pipeline transportation. Here flow based algorithm focusing to transport liquid goods with maximum capacity with shortest distance, this algorithm developed with the sense of basic pert and critical path method. Conclusion/Recommendations: This flow based algorithm helps to give optimal result for transporting maximum capacity with minimum cost. It could be used in the juice factory, milk industry and its best alternate for the vehicle routing problem.

  3. Alkaline quinone flow battery.

    Science.gov (United States)

    Lin, Kaixiang; Chen, Qing; Gerhardt, Michael R; Tong, Liuchuan; Kim, Sang Bok; Eisenach, Louise; Valle, Alvaro W; Hardee, David; Gordon, Roy G; Aziz, Michael J; Marshak, Michael P

    2015-09-25

    Storage of photovoltaic and wind electricity in batteries could solve the mismatch problem between the intermittent supply of these renewable resources and variable demand. Flow batteries permit more economical long-duration discharge than solid-electrode batteries by using liquid electrolytes stored outside of the battery. We report an alkaline flow battery based on redox-active organic molecules that are composed entirely of Earth-abundant elements and are nontoxic, nonflammable, and safe for use in residential and commercial environments. The battery operates efficiently with high power density near room temperature. These results demonstrate the stability and performance of redox-active organic molecules in alkaline flow batteries, potentially enabling cost-effective stationary storage of renewable energy. PMID:26404834

  4. Validated dynamic flow model

    DEFF Research Database (Denmark)

    Knudsen, Torben

    2011-01-01

    The purpose with this deliverable 2.5 is to use fresh experimental data for validation and selection of a flow model to be used for control design in WP3-4. Initially the idea was to investigate the models developed in WP2. However, in the project it was agreed to include and focus on a additive...... model structure suggested by University of Lund the WP4 leader. This particular model structure has the advantages that it fits better into the control design frame work used by WP3-4 compared to the model structures previously developed in WP2. The different model structures are first summarised...... model turns out not to be useful for prediction of the flow. Moreover, standard Box Jenkins model structures and multiple output auto regressive models proves to be superior as they can give useful predictions of the flow....

  5. Interactive Flow in Exercise Pedagogy

    Science.gov (United States)

    Lloyd, Rebecca; Smith, Stephen

    2006-01-01

    A phenomenology of the bodily experience of interactive flow adds to Csikszentmihalyi's flow theory. Whereas Csikszentmihalyi attended to teachers' and students' experiences of flow separately, this inquiry explores flow through three water-inspired layers of physical interaction between fitness professionals and their clients. Teaching fitness is…

  6. Mean curvature flow without singularities

    OpenAIRE

    Sáez, Mariel; Schnürer, Oliver Christian

    2012-01-01

    We study graphical mean curvature flow of complete solutions defined on subsets of Euclidean space.We obtain smooth long time existence. The projections of the evolving graphs also solve mean curvature flow. Hence this approach allows us to smoothly flow through singularities by studying graphical mean curvature flow in one additional dimension.

  7. Fluid Flow at Branching Junctions

    OpenAIRE

    Sochi, Taha

    2013-01-01

    The flow of fluids at branching junctions plays important kinematic and dynamic roles in most biological and industrial flow systems. The present paper highlights some key issues related to the flow of fluids at these junctions with special emphasis on the biological flow networks particularly blood transportation vasculature.

  8. Efficiency of osmotic pipe flows

    DEFF Research Database (Denmark)

    Haaning, Louise Sejling; Jensen, Kaare Hartvig; Helix Nielsen, Claus;

    2013-01-01

    efficiency of these flows is limited by the presence of “unstirred” concentration boundary layers near the tube walls, and our primary aim is to understand and quantify these layers and their effect on the flow. We measure the outlet flow rate Qout while varying the inlet flow rate Q*, concentration c...

  9. Multiscale Image Based Flow Visualization

    NARCIS (Netherlands)

    Telea, Alexandru; Strzodka, Robert

    2006-01-01

    We present MIBFV, a method to produce real-time, multiscale animations of flow datasets. MIBFV extends the attractive features of the Image-Based Flow Visualization (IBFV) method, i.e. dense flow domain coverage with flow-aligned noise, real-time animation, implementation simplicity, and few (or no)

  10. Three-Dimensional Flows

    CERN Document Server

    Araujo, Vitor; Viana, Marcelo

    2010-01-01

    In this book, the authors present the elements of a general theory for flows on three-dimensional compact boundaryless manifolds, encompassing flows with equilibria accumulated by regular orbits. The book aims to provide a global perspective of this theory and make it easier for the reader to digest the growing literature on this subject. This is not the first book on the subject of dynamical systems, but there are distinct aspects which together make this book unique. Firstly, this book treats mostly continuous time dynamical systems, instead of its discrete counterpart, exhaustively treated

  11. Multiphase cooling flows

    OpenAIRE

    Thomas, Peter A.

    1996-01-01

    I discuss the multiphase nature of the intracluster medium whose neglect can lead to overestimates of the baryon fraction of clusters by up to a factor of two. The multiphase form of the cooling flow equations are derived and reduced to a simple form for a wide class of self-similar density distributions. It is shown that steady-state cooling flows are \\emph{not} consistent with all possible emissivity profiles which can therefore be used as a test of the theory. In combination, they provide ...

  12. Mechanics of fluid flow

    CERN Document Server

    Basniev, Kaplan S; Chilingar, George V 0

    2012-01-01

    The mechanics of fluid flow is a fundamental engineering discipline explaining both natural phenomena and human-induced processes, and a thorough understanding of it is central to the operations of the oil and gas industry.  This book, written by some of the world's best-known and respected petroleum engineers, covers the concepts, theories, and applications of the mechanics of fluid flow for the veteran engineer working in the field and the student, alike.  It is a must-have for any engineer working in the oil and gas industry.

  13. Spiral Flow Separator

    Science.gov (United States)

    Robertson, Glen A.

    1993-01-01

    Proposed liquid-separating device relies on centrifugal force in liquid/liquid or liquid/solid mixture in spiral path. Operates in continuous flow at relatively high rates. Spiral tubes joined in sequence, with outlet tubes connected to joints. Cross-sectional areas of successive spiral tubes decreases by cross-sectional areas of outlet tubes. Centrifugal force pushes denser particles or liquids to outer edge of spiral, where removed from flow. Principle exploited to separate solids from wastewater, oil from fresh or salt water, or contaminants from salt water before evaporation. Also used to extract such valuable materials as precious metals from slurries.

  14. Flow Injection Analysis

    DEFF Research Database (Denmark)

    Hansen, Elo Harald

    2004-01-01

    This chapter provides an introduction to automated chemical analysis, which essentially can be divided into two groups: batch assays, where the solution is stationary while the container is moved through a number of stations where various unit operations performed; and continuous-flow procedures......, where the system is stationary while the solution moves through a set of conduits in which all required manipulations are performed. Emphasis is placed on flow injection analysis (FIA) and its further developments, that is, sequential injection analysis (SIA) and the Lab-on-Valve (LOV) approach. Since...

  15. Transverse oscillation vector flow imaging for transthoracic echocardiography

    DEFF Research Database (Denmark)

    Bradway, David; Lindskov Hansen, Kristoffer; Nielsen, Michael Bachmann;

    2015-01-01

    velocity flow images. A flow pump was programmed for constant flow for in vitro acquisitions at varying depths in a tissue-mimicking fluid. Additionally, mitral, aortic,and tricuspid valves of two healthy volunteers were scanned from intercostal acoustic windows. The acquired RF data were beamformed via......This work presents the development and first results of in vivo transthoracic cardiac imaging using an implementation of Vector Flow Imaging (VFI) via the Transverse Oscillation (TO) method on a phased-array transducer. Optimal selection of the lateral wavelength of the transversely...... the TO method, and fourth-order estimators were employed for the velocity estimation. The resulting images were compared with those from conventional spectral Doppler and color flow mapping sequences. VFI is shown to be a clinically-feasible tool, which enables new exibility for choosing acoustic windows...

  16. International symposium on slurry flows

    International Nuclear Information System (INIS)

    This book presents the papers given at a conference on two-phase slurry flow. Topics considered at the conference included flow models, drag, flow rate, stresses in a fluid-solid mixture, kinetic models, the shear viscosity of dense-phase slurries at varying shear rates, the modeling of particulates based on the Markov process, fluid-particle flows in geothermal drilling applications, two-phase nozzle flow, laminar flow, centrifugal slurry pumps, slurry pipeline flow, and the beneficiation of coal by agglomeration during hydraulic transport

  17. Mapping blood flow directionality in the human brain.

    Science.gov (United States)

    Park, Sung-Hong; Do, Won-Joon; Choi, Seung Hong; Zhao, Tiejun; Bae, Kyongtae Ty

    2016-07-01

    Diffusion properties of tissue are often expressed on the basis of directional variance, i.e., diffusion tensor imaging. In comparison, common perfusion-weighted imaging such as arterial spin labeling yields perfusion in a scalar quantity. The purpose of this study was to test the feasibility of mapping cerebral blood flow directionality using alternate ascending/descending directional navigation (ALADDIN), a recently-developed arterial spin labeling technique with sensitivity to blood flow directions. ALADDIN was applied along 3 orthogonal directions to assess directional blood flow in a vector form and also along 6 equally-spaced directions to extract blood flow tensor matrix (P) based on a blood flow ellipsoid model. Tensor elements (eigenvalues, eigenvectors, etc) were calculated to investigate characteristics of the blood flow tensor, in comparison with time-of-flight MR angiogram. While the directions of the main eigenvectors were heterogeneous throughout the brain, regional clusters of blood flow directionality were reproducible across subjects. The technique could show heterogeneous blood flow directionality within and around brain tumor, which was different from that of the contralateral normal side. The proposed method is deemed to provide information of blood flow directionality, which has not been demonstrated before. The results warrant further studies to assess changes in the directionality map as a function of scan parameters, to understand the signal sources, to investigate the possibility of mapping local blood perfusion directionality, and to evaluate its usefulness for clinical diagnosis.

  18. Pulsed photoacoustic flow imaging with a handheld system.

    Science.gov (United States)

    van den Berg, Pim J; Daoudi, Khalid; Steenbergen, Wiendelt

    2016-02-01

    Flow imaging is an important technique in a range of disease areas, but estimating low flow speeds, especially near the walls of blood vessels, remains challenging. Pulsed photoacoustic flow imaging can be an alternative since there is little signal contamination from background tissue with photoacoustic imaging. We propose flow imaging using a clinical photoacoustic system that is both handheld and portable. The system integrates a linear array with 7.5 MHz central frequency in combination with a high-repetition-rate diode laser to allow high-speed photoacoustic imaging--ideal for this application. This work shows the flow imaging performance of the system in vitro using microparticles. Both two-dimensional (2-D) flow images and quantitative flow velocities from 12 to 75  mm/s were obtained. In a transparent bulk medium, flow estimation showed standard errors of ∼7% the estimated speed; in the presence of tissue-realistic optical scattering, the error increased to 40% due to limited signal-to-noise ratio. In the future, photoacoustic flow imaging can potentially be performed in vivo using fluorophore-filled vesicles or with an improved setup on whole blood.

  19. Optical diagnostics of intermittent flows

    DEFF Research Database (Denmark)

    Okulov, V.L.; Naumov, I.V.; Sørensen, Jens Nørkær

    2007-01-01

    image velocimetry, frequently give erroneous results, especially for the transition flow and developed nonstationary flow. However, their combined use in diagnostics of unsteady (intermittent) flows significantly improves both the temporal and spatial resolution of measurements. Such a complex approach......The efficiency of combined use of different optical techniques for flow diagnostics is demonstrated with the practically important case of intense swirling flows. It is shown that, when applied separately, commonly used optical measuring techniques, such as laser Doppler anemometry and particle...

  20. The fluctuations of quadrangular flow

    CERN Document Server

    Giacalone, Giuliano; Noronha-Hostler, Jacquelyn; Ollitrault, Jean-Yves

    2016-01-01

    The ATLAS Collaboration has measured for the first time the fourth cumulant of quadrangular flow, $v_4\\{4\\}^4$. Unlike the fourth cumulants of elliptic and triangular flows, it presents a change of sign above 30\\% centrality. We show that this change of sign is predicted by event-by-event hydrodynamics. We argue that it results from the combined effects of a nonlinear hydrodynamic response, which couples quadrangular flow to elliptic flow, and elliptic flow fluctuations.

  1. Nucleon flow and fragment flow in heavy ion reactions

    International Nuclear Information System (INIS)

    The collective flow of nucleons and that of fragments in the 12C+12C reaction below 150 MeV/nucleon are calculated with the antisymmetrized version of molecular dynamics combined with the statistical decay calculation. The density dependent Gogny force is used as the effective interaction. The calculated balance energy is about 100 MeV/nucleon, which is close to the observed value. Below the balance energy, the absolute value of the fragment flow is larger than that of nucleon flow, which is also in accordance with data. The dependence of the flow on the stochastic collision cross section and its origin are discussed. All the results are naturally understood by introducing the concept of two components of flow: the flow of dynamically emitted nucleons and the flow of the nuclear matter which contributes to both the flow of fragments and the flow of nucleons due to the statistical decay

  2. Up-flow and down-flow burnout

    International Nuclear Information System (INIS)

    The effects of buoyancy force on the burn-out phenomenon have been studied with Freon 12 at low mass flow-rates. The critical heat flow is higher in up-flow than in down-flow (up to 35%) and this difference depends on the flow patterns occurring along the tube. The main influence of the buoyancy force seems to be localized in subcooled and bubble flow regions. A correlation between crisis qualities in down-flow and in up-flow has been obtained for these parameter ranges: - specific mass flow-rate G, 100 + 1000 kg/m2s; pressure 0.25 < p/psub(cr) < 0.60; inlet quality -0.40 < Xsub(in) < + 0.20. (author)

  3. Bottleneck flows in networks

    CERN Document Server

    Punnen, Abraham P

    2007-01-01

    The bottleneck network flow problem (BNFP) is a generalization of several well-studied bottleneck problems such as the bottleneck transportation problem (BTP), bottleneck assignment problem (BAP), bottleneck path problem (BPP), and so on. In this paper we provide a review of important results on this topic and its various special cases. We observe that the BNFP can be solved as a sequence of $O(\\log n)$ maximum flow problems. However, special augmenting path based algorithms for the maximum flow problem can be modified to obtain algorithms for the BNFP with the property that these variations and the corresponding maximum flow algorithms have identical worst case time complexity. On unit capacity network we show that BNFP can be solved in $O(\\min \\{{m(n\\log n)}^{{2/3}}, m^{{3/2}}\\sqrt{\\log n}\\})$. This improves the best available algorithm by a factor of $\\sqrt{\\log n}$. On unit capacity simple graphs, we show that BNFP can be solved in $O(m \\sqrt {n \\log n})$ time. As a consequence we have an $O(m \\sqrt {n \\l...

  4. Flow Injection Analysis

    DEFF Research Database (Denmark)

    Hansen, Elo Harald

    1998-01-01

    Learning objectives:* To provide an introduction to automated assays* To describe the basic principles of FIA * To demonstrate the capabilities of FIA in relation to batch assays and conventional continuous flow systems* To show that FIA allows one to augment existing analytical techniques* To show...

  5. Let It Flow

    Institute of Scientific and Technical Information of China (English)

    Alphonce Shiundu

    2011-01-01

    @@ AFRICA'S Gold Coast, otherwise known as the Republic of Ghana, marked the first 100 days since its oil taps began running, on March 25, 2011.The oil in question flows from the country s offshore Iubilee oilfield, recognized by the stakeholders to be the largest oil discovery in West Africa in the last 10 to 15 years.

  6. Proportionate Flow Shop Games

    NARCIS (Netherlands)

    Estevez Fernandez, M.A.; Mosquera, M.A.; Borm, P.E.M.; Hamers, H.J.M.

    2006-01-01

    In a proportionate flow shop problem several jobs have to be processed through a fixed sequence of machines and the processing time of each job is equal on all machines.By identifying jobs with agents, whose costs linearly depend on the completion time of their jobs, and assuming an initial processi

  7. Lateral flow assays

    NARCIS (Netherlands)

    Posthuma-Trumpie, G.A.; Amerongen, van A.

    2012-01-01

    A simple version of immunochemical-based methods is the Lateral Flow Assay (LFA). It is a dry chemistry technique (reagents are included); the fluid from the sample runs through a porous membrane (often nitrocellulose) by capillary force. Typically the membrane is cut as a strip of 0.5*5 cm. In most

  8. Probabilistic Load Flow

    DEFF Research Database (Denmark)

    Chen, Peiyuan; Chen, Zhe; Bak-Jensen, Birgitte

    2008-01-01

    This paper reviews the development of the probabilistic load flow (PLF) techniques. Applications of the PLF techniques in different areas of power system steady-state analysis are also discussed. The purpose of the review is to identify different available PLF techniques and their corresponding...

  9. Flow on noisy terrains

    DEFF Research Database (Denmark)

    Tsirogiannis, Konstantinos; Haverkort, Herman

    2011-01-01

    Computing watersheds on triangulated terrain models in a robust manner is a difficult task as it is sensitive to noise that appears in the elevation values of the input. This is amplified by the existence of many very small watersheds (corresponding to spurious minima) that obscure the overall hy...... use a robust flow model together with exact arithmetic....

  10. Flow control using ferrofluids

    Science.gov (United States)

    Cornat, Francois; Beck, David; Jacobi, Ian; Stone, Howard

    2013-11-01

    A novel flow control technique is proposed which employs a ferrofluidic lubricant infused in a micro-patterned substrate as a ``morphing surface'' for control of wall-bounded flows. Traditionally, morphing surfaces produce dynamic changes in the curvature and roughness of solid substrates for active control of high Reynolds number flow features such as boundary layer separation and turbulent streaks. We show how these surface modifications can be achieved with a thin liquid layer in the presence of a normal magnetic field. By impregnating a chemically-treated, micro-patterned surface with a fluorinated ferrofluid, the fluid is maintained as a thin super-hydrophobic film and can be redistributed on the substrate by magnetic forces to dynamically reveal or conceal the underlying surface roughness. Moreover, the surface topography of the ferrofluid film itself can be modified to produce an enhanced roughness, beyond the scale of the underlying substrate pattern. Both types of ferrofluidic surface modifications are studied in micro- and macro- scale channels in order to assess the feasibility of flow modification at low to moderate Reynolds numbers.

  11. Sinuous flow in metals.

    Science.gov (United States)

    Yeung, Ho; Viswanathan, Koushik; Compton, Walter Dale; Chandrasekar, Srinivasan

    2015-08-11

    Annealed metals are surprisingly difficult to cut, involving high forces and an unusually thick "chip." This anomaly has long been explained, based on ex situ observations, using a model of smooth plastic flow with uniform shear to describe material removal by chip formation. Here we show that this phenomenon is actually the result of a fundamentally different collective deformation mode--sinuous flow. Using in situ imaging, we find that chip formation occurs via large-amplitude folding, triggered by surface undulations of a characteristic size. The resulting fold patterns resemble those observed in geophysics and complex fluids. Our observations establish sinuous flow as another mesoscopic deformation mode, alongside mechanisms such as kinking and shear banding. Additionally, by suppressing the triggering surface undulations, sinuous flow can be eliminated, resulting in a drastic reduction of cutting forces. We demonstrate this suppression quite simply by the application of common marking ink on the free surface of the workpiece material before the cutting. Alternatively, prehardening a thin surface layer of the workpiece material shows similar results. Besides obvious implications to industrial machining and surface generation processes, our results also help unify a number of disparate observations in the cutting of metals, including the so-called Rehbinder effect. PMID:26216980

  12. Validation of an optical flow algorithm to measure blood flow waveforms in arteries using dynamic digital x-ray images

    Science.gov (United States)

    Rhode, Kawal; Lambrou, Tryphon; Hawkes, David J.; Hamilton, George; Seifalian, Alexander M.

    2000-06-01

    We have developed a weighted optical flow algorithm for the extraction of instantaneous blood velocity from dynamic digital x-ray images of blood vessels. We have carried out in- vitro validation of this technique. A pulsatile physiological blood flow circuit was constructed using sections of silicone tubing to simulate blood vessels with whole blood as the fluid. Instantaneous recording of flow from an electromagnetic flow meter (EMF) provided the gold standard measurement. Biplanar dynamic digital x-ray images of the blood vessel with injection of contrast medium were acquired at 25 fps using a PC frame capture card. Imaging of a Perspex calibration cube allowed 3D reconstruction of the vessel and determination of true dimensions. Blood flow waveforms were calculated off-line on a Sun workstation using the new algorithm. The correlation coefficient between instantaneous blood flow values obtained from the EMF and the x-ray method was r equals 0.871, n equals 1184, p less than 0.0001. The correlation coefficient for average blood flow was r equals 0.898, n equals 16, p less than 0.001. We have successfully demonstrated that our new algorithm can measure pulsatile blood flow in a vessel phantom. We aim to use this algorithm to measure blood flow clinically in patients undergoing vascular interventional procedures.

  13. Physics of Traffic Flow

    Science.gov (United States)

    Davis, L. C.

    2015-03-01

    The Texas A&M Transportation Institute estimated that traffic congestion cost the United States 121 billion in 2011 (the latest data available). The cost is due to wasted time and fuel. In addition to accidents and road construction, factors contributing to congestion include large demand, instability of high-density free flow and selfish behavior of drivers, which produces self-organized traffic bottlenecks. Extensive data collected on instrumented highways in various countries have led to a better understanding of traffic dynamics. From these measurements, Boris Kerner and colleagues developed a new theory called three-phase theory. They identified three major phases of flow observed in the data: free flow, synchronous flow and wide moving jams. The intermediate phase is called synchronous because vehicles in different lanes tend to have similar velocities. This congested phase, characterized by lower velocities yet modestly high throughput, frequently occurs near on-ramps and lane reductions. At present there are only two widely used methods of congestion mitigation: ramp metering and the display of current travel-time information to drivers. To find more effective methods to reduce congestion, researchers perform large-scale simulations using models based on the new theories. An algorithm has been proposed to realize Wardrop equilibria with real-time route information. Such equilibria have equal travel time on alternative routes between a given origin and destination. An active area of current research is the dynamics of connected vehicles, which communicate wirelessly with other vehicles and the surrounding infrastructure. These systems show great promise for improving traffic flow and safety.

  14. Flow cytometry data standards

    Directory of Open Access Journals (Sweden)

    Kollmann Tobias R

    2011-03-01

    Full Text Available Abstract Background Flow cytometry is a widely used analytical technique for examining microscopic particles, such as cells. The Flow Cytometry Standard (FCS was developed in 1984 for storing flow data and it is supported by all instrument and third party software vendors. However, FCS does not capture the full scope of flow cytometry (FCM-related data and metadata, and data standards have recently been developed to address this shortcoming. Findings The Data Standards Task Force (DSTF of the International Society for the Advancement of Cytometry (ISAC has developed several data standards to complement the raw data encoded in FCS files. Efforts started with the Minimum Information about a Flow Cytometry Experiment, a minimal data reporting standard of details necessary to include when publishing FCM experiments to facilitate third party understanding. MIFlowCyt is now being recommended to authors by publishers as part of manuscript submission, and manuscripts are being checked by reviewers and editors for compliance. Gating-ML was then introduced to capture gating descriptions - an essential part of FCM data analysis describing the selection of cell populations of interest. The Classification Results File Format was developed to accommodate results of the gating process, mostly within the context of automated clustering. Additionally, the Archival Cytometry Standard bundles data with all the other components describing experiments. Here, we introduce these recent standards and provide the very first example of how they can be used to report FCM data including analysis and results in a standardized, computationally exchangeable form. Conclusions Reporting standards and open file formats are essential for scientific collaboration and independent validation. The recently developed FCM data standards are now being incorporated into third party software tools and data repositories, which will ultimately facilitate understanding and data reuse.

  15. Experimental Investigation of Stator Flow in Diagonal Flow Fan

    Institute of Scientific and Technical Information of China (English)

    Jie Wang; Yoichi Kinoue; Norimasa Shiomi; Toshiaki Setoguchi; Kenji Kaneko; Yingzi Jin

    2008-01-01

    perimental investigations were conducted for the internal flow of the stator of the diagonal flow fan. Comer separation near the hub surface and the suction surface of the stator blade are focused on. At the design flow rate, the values of the axial velocity and the total pressure at stator outlet decrease near the suction surface at around the hub surface by the influence of the comer wall. At low flow rate of 80-90 % of the design flow rate, the comer separation between the suction surface and the hub surface can be found, which become widely spread at 80 % of the design flow rate.

  16. HISTIOCYTOSIS X: CLINICAL OBSERVATIONS

    Directory of Open Access Journals (Sweden)

    E. Y. Ponomareva

    2014-07-01

    Full Text Available Two clinical cases of pulmonary Langerhans cell histiocytosis X have been analyzed demonstrating lung and other inner organ pathology, common clinical and X-ray features but different life prognosis.

  17. HISTIOCYTOSIS X: CLINICAL OBSERVATIONS

    OpenAIRE

    E. Y. Ponomareva; A. P. Rebrov; E. E. Archangelskaja; A. A. Roshchina; R. N. Steshenko; A. S. Bukia; N. V. Dvornikova; N. N. Moskaleva

    2014-01-01

    Two clinical cases of pulmonary Langerhans cell histiocytosis X have been analyzed demonstrating lung and other inner organ pathology, common clinical and X-ray features but different life prognosis.

  18. Fertility Clinic Success Rates

    Science.gov (United States)

    ... and Autism 2013 Assisted Reproductive Technology Fertility Clinic Success Rates Report Recommend on Facebook Tweet Share Compartir 2013 ART Fertility Clinic Success Rates Report [PDF - 1MB] Bookmarks and thumbnails are ...

  19. Participating in Clinical Trials

    Medline Plus

    Full Text Available ... trial is to find out if an experimental drug, therapy, medical device, lifestyle change, or test will ... disease. Phases of Clinical Trials Clinical trials of drugs are usually described based on their phase. The ...

  20. Clinical Laboratory Fee Schedule

    Data.gov (United States)

    U.S. Department of Health & Human Services — Outpatient clinical laboratory services are paid based on a fee schedule in accordance with Section 1833(h) of the Social Security Act. The clinical laboratory fee...

  1. Research Areas - Clinical Trials

    Science.gov (United States)

    Information about NCI programs and initiatives that sponsor, conduct, develop, or support clinical trials, including NCI’s Clinical Trial Network (NCTN) and NCI Community Oncology Research Program (NCORP) initiatives.

  2. NIH Clinical Centers

    Data.gov (United States)

    Federal Laboratory Consortium — The NIH Clinical Center consists of two main facilities: The Mark O. Hatfield Clinical Research Center, which opened in 2005, houses inpatient units, day hospitals,...

  3. Spina Bifida Clinic Directory

    Science.gov (United States)

    ... Bifida Clinic Children’s Hospital New Orleans 200 Henry Clay Avenue (Pediatric-22) New Orleans, LA 70118 504- ... www.reach-clinic.org Back to top Oregon Child Development & Rehabilitation Center Oregon Health & Science University (pediatric ...

  4. Flow networks analysis and optimization of repairable flow networks, networks with disturbed flows, static flow networks and reliability networks

    CERN Document Server

    Todinov, Michael T

    2013-01-01

    Repairable flow networks are a new area of research, which analyzes the repair and flow disruption caused by failures of components in static flow networks. This book addresses a gap in current network research by developing the theory, algorithms and applications related to repairable flow networks and networks with disturbed flows. The theoretical results presented in the book lay the foundations of a new generation of ultra-fast algorithms for optimizing the flow in networks after failures or congestion, and the high computational speed creates the powerful possibility of optimal control

  5. FLOW-Methode - Methodenbeschreibung zur Anwendung von FLOW

    CERN Document Server

    Stapel, Kai

    2012-01-01

    Information of many kinds is flowing in software projects and organizations. Requirements have to flow from the customer to the developers. Testers need to know the requirements as well. Boundary conditions and design decisions have to be at the right place at the right time. Information flow analysis with FLOW facilitates modeling of mode and route of the flow of information and experience independent of the development methodology. Experience often acts as a control factor, because experienced developers can process and route information more efficiently. Therefore, experience needs to be at the right place at the right time, too. However, most valuable experiences never get documented. Since information and experience is flowing in agile as well as in traditional environments, the FLOW method does not distinguish between agile and traditional, but only between how the flows are shaped. ---- In Softwareprojekten flie{\\ss}en vielerlei Informationen. Anforderungen m\\"ussen vom Kunden zu den Entwicklern gelang...

  6. Evolution of Clinical Enzymology

    OpenAIRE

    Büttner, J

    1981-01-01

    The evolution of clinical enzymology is discussed in relation to the history of general enzymology and clinical chemistry. The discussion is limited to the period from 1835 (definition of catalysis by Berzelius) to 1935 (description of the optical test by Warburg). In conclusion, a general account is given of the introduction of the concept of quantitative enzyme activity determination into clinical medicine.

  7. Participating in Clinical Trials

    Medline Plus

    Full Text Available ... was provided by the National Library of Medicine Topic last reviewed: December 2013 For an enhanced version of this page please turn Javascript on. Participating in Clinical Trials About Clinical Trials A Research Study With Human Subjects A clinical trial is ...

  8. Clinical document architecture.

    Science.gov (United States)

    Heitmann, Kai

    2003-01-01

    The Clinical Document Architecture (CDA), a standard developed by the Health Level Seven organisation (HL7), is an ANSI approved document architecture for exchange of clinical information using XML. A CDA document is comprised of a header with associated vocabularies and a body containing the structural clinical information. PMID:15061557

  9. 双胎反向动脉灌注序列征中两胎脐动脉血流阻力指数差值对评估泵血儿预后的临床意义%Clinical value of diffe rence in umbilical artery blood flow resistive index between pump and acardiac twins in pre-dicting outcome of pump twin by twin reversed-arterial perfusion sequence

    Institute of Scientific and Technical Information of China (English)

    陈昌宇; 解丽梅

    2016-01-01

    Objective To investigate the clinical value of umbilical artery blood flow resistance index (RI) difference between pump twins and acardiacus fetus by twin reversed-arterial perfusion (TRAP) sequence. Methods A total of 15 pregnant women with TRAP in China Medical University Affiliated Shengjing Hospital from 2009 to 2014 were enrolled, aged 19-36 years old with mean age of 26.53 years old. The gestational age was 13 - 27 weeks with mean of 21.73 weeks. Umbilical artery blood flow RI of pump twin and acardiacus were respectively measured by ultrasound, and the difference value of umbilical artery blood flow RI was calculated. Results Three pump twins were detected as heart failure, the difference value of their umbilical artery blood flow RI were small as 0.05, 0.07 and 0.13, respectively, and intrauterine death occurred after one week. Eight cases were given radio frequency ablation therapy, the difference value of umbilical artery blood flow RI of 7 pump twins were 0.16 - 0.30, and fetus were survived. The one pump twin showed difference value of umbilical artery blood flow RI of 0.17, and intrauterine death occurred after surgery. The difference value of umbilical artery blood flow RI of one pump twin was 0.34, and given conservative treatment due to the poor blood flow in acardiacus. The difference value of umbilical artery blood flow RI of one pump twin was 0.10, which terminated the pregnancy for maternal pregnancy-induced hypertension. The difference value of umbilical artery blood flow RI of one pump twin was 0.20, which showed chromosomal abnormalities, and one case performed abortion for low gestational age. Conclusion It is demonstrated that the difference value of umbilical artery blood flow RI between pump twin and acardiacus is significant on evaluation and treatment of TRAP, which means the bigger the RI difference value, the better prognosis.%目的:探讨双胎反向动脉灌注序列征(TRAP)中泵血儿与无心畸胎脐动脉血流阻力

  10. Operative considerations in implantation of the Perma-Flow graft.

    Science.gov (United States)

    Emery, R W; Joyce, L D; Arom, K V; King, R M; Nicoloff, D M

    1994-12-01

    The Perma-Flow coronary bypass graft (Possis Medical, Inc, Minneapolis, MN) currently is undergoing expanded clinical trial. From November 1992 through June 1994 we have used this artificial conduit in 8 patients without autologous alternatives. These cases allowed the establishment of a technical basis for successful implantation of this graft. All studied coronary anastomoses are patent.

  11. Hydrodynamics and Flow

    CERN Document Server

    Hirano, Tetsufumi; Bilandzic, Ante

    2008-01-01

    In this lecture note, we present several topics on relativistic hydrodynamics and its application to relativistic heavy ion collisions. In the first part we give a brief introduction to relativistic hydrodynamics in the context of heavy ion collisions. In the second part we present the formalism and some fundamental aspects of relativistic ideal and viscous hydrodynamics. In the third part, we start with some basic checks of the fundamental observables followed by discussion of collective flow, in particular elliptic flow, which is one of the most exciting phenomenon in heavy ion collisions at relativistic energies. Next we discuss how to formulate the hydrodynamic model to describe dynamics of heavy ion collisions. Finally, we conclude the third part of the lecture note by showing some results from ideal hydrodynamic calculations and by comparing them with the experimental data.

  12. Slow viscous flow

    CERN Document Server

    Langlois, William E

    2014-01-01

    Leonardo wrote, 'Mechanics is the paradise of the mathematical sciences, because by means of it one comes to the fruits of mathematics' ; replace 'Mechanics' by 'Fluid mechanics' and here we are." -    from the Preface to the Second Edition Although the exponential growth of computer power has advanced the importance of simulations and visualization tools for elaborating new models, designs and technologies, the discipline of fluid mechanics is still large, and turbulence in flows remains a challenging problem in classical physics. Like its predecessor, the revised and expanded Second Edition of this book addresses the basic principles of fluid mechanics and solves fluid flow problems where viscous effects are the dominant physical phenomena. Much progress has occurred in the nearly half a century that has passed since the edition of 1964. As predicted, aspects of hydrodynamics once considered offbeat have risen to importance. For example, the authors have worked on problems where variations in viscosity a...

  13. Fracture flow code

    International Nuclear Information System (INIS)

    The hydrology of the SCV site will be modelled utilizing discrete fracture flow models. These models are complex, and can not be fully cerified by comparison to analytical solutions. The best approach for verification of these codes is therefore cross-verification between different codes. This is complicated by the variation in assumptions and solution techniques utilized in different codes. Cross-verification procedures are defined which allow comparison of the codes developed by Harwell Laboratory, Lawrence Berkeley Laboratory, and Golder Associates Inc. Six cross-verification datasets are defined for deterministic and stochastic verification of geometric and flow features of the codes. Additional datasets for verification of transport features will be documented in a future report. (13 figs., 7 tabs., 10 refs.) (authors)

  14. Lateral flow assays.

    Science.gov (United States)

    Koczula, Katarzyna M; Gallotta, Andrea

    2016-06-30

    Lateral flow assays (LFAs) are the technology behind low-cost, simple, rapid and portable detection devices popular in biomedicine, agriculture, food and environmental sciences. This review presents an overview of the principle of the method and the critical components of the assay, focusing on lateral flow immunoassays. This type of assay has recently attracted considerable interest because of its potential to provide instantaneous diagnosis directly to patients. The range and interpretation of results and parameters used for evaluation of the assay will also be discussed. The main advantages and disadvantages of LFAs will be summarized and relevant future improvements to testing devices and strategies will be proposed. Finally, the major recent advances and future diagnostic applications in the LFA field will be explored. PMID:27365041

  15. Structural power flow measurement

    Energy Technology Data Exchange (ETDEWEB)

    Falter, K.J.; Keltie, R.F.

    1988-12-01

    Previous investigations of structural power flow through beam-like structures resulted in some unexplained anomalies in the calculated data. In order to develop structural power flow measurement as a viable technique for machine tool design, the causes of these anomalies needed to be found. Once found, techniques for eliminating the errors could be developed. Error sources were found in the experimental apparatus itself as well as in the instrumentation. Although flexural waves are the carriers of power in the experimental apparatus, at some frequencies longitudinal waves were excited which were picked up by the accelerometers and altered power measurements. Errors were found in the phase and gain response of the sensors and amplifiers used for measurement. A transfer function correction technique was employed to compensate for these instrumentation errors.

  16. An orographic flow diagramme

    Science.gov (United States)

    Opsanger Jonassen, Marius; Ólafsson, Haraldur; Ágústsson, Hálfdán

    2016-04-01

    Motivated by the need to relate some key features of atmospheric flow over mountains to the elevation of the inversion and wind speed, many numerical experiments are made in order to create a diagramme a la Vosper (2004). The simulations are carried out with the WRF model and stationary boundary-conditions. A neutral boundary-layer is capped by a 10K inversion, of which the height varies. The mountain is 1 km high and the incoming winds are 10,15 or 20 m/s. The surface has zo=0.1m. Vortices, vortex shedding, lee waves and hydraulic jump are detected and related to values of the height of the inversion and the Froude number. Cases of real flow are compared to the idealized results.

  17. Blood flow measurements during hemodialysis vascular access interventions - Catheter-based thermodilution or Doppler ultrasound?

    DEFF Research Database (Denmark)

    Heerwagen, Søren T; Hansen, Marc A; Schroeder, Torben V;

    2012-01-01

    Purpose: To test the clinical performance of catheter-based thermodilution and Doppler ultrasound of the feeding brachial artery for blood flow measurements during hemodialysis vascular access interventions.Methods: Thirty patients with arteriovenous fistulas who underwent 46 interventions had...

  18. Discrete Morse flow for Ricci flow and Porous Media equation

    CERN Document Server

    Ma, Li

    2012-01-01

    In this paper, we study the discrete Morse flow for the Ricci flow on football, which is the 2-sphere with removed north and south poles and with the metric $g_0$ of constant scalar curvature, and and for Porous media equation on a bounded regular domain in the plane. We show that with a suitable assumption about $g(0)$ we have a weak approximated discrete Morse flow for the approximated Ricci flow and Porous media equation on any time intervals.

  19. Cash-Flow Tax

    OpenAIRE

    Parthasarathi Shome; Christian Schutte

    1993-01-01

    The cash-flow tax has been proposed as an alternative to corporate income tax on grounds of clarity and simplicity in defining the tax base in the face of widespread departures from the comprehensive income tax in actual practice. Variants of the tax, with their advantages and disadvantages, demonstrate that it would require careful design. Simplicity is not an obvious property because of expectable administration problems related to tax avoidance and evasion through transfer pricing; to infl...

  20. Gaseous Flows in Galaxies

    OpenAIRE

    Combes, F.

    2007-01-01

    The gas component plays a major role in the dynamics of spiral galaxies, because of its dissipative character, and its ability to exchange angular momentum with stars in the disk. Due to its small velocity dispersion, it triggers gravitational instabilities, and the corresponding non-axisymmetric patterns produce gravity torques, which mediate these angular momentum exchanges. When a srong bar pattern develops with the same pattern speed all over the disk, only gas inside corotation can flow ...

  1. Flow og fordybelse

    DEFF Research Database (Denmark)

    Andersen, Frans Ørsted

    2010-01-01

    Artiklen handler om flow og fordybelse i et nyt tværfagligt / naturfagligt undervisningskoncept, "Overvågningens dilemma", til brug i folkeskolens 7.-9.kl. og på gymnasiale uddannelser. Konceptet sætter fokus på den overvågning der foregår og er mulig i nutidens IT og hi-tec samfund og der arbejdes...

  2. Intelligent flow friction estimation

    OpenAIRE

    Dejan Brkić; Žarko Ćojbašić

    2016-01-01

    Nowadays, the Colebrook equation is used as a mostly accepted relation for the calculation of fluid flow friction factor. However, the Colebrook equation is implicit with respect to the friction factor (λ). In the present study, a noniterative approach using Artificial Neural Network (ANN) was developed to calculate the friction factor. To configure the ANN model, the input parameters of the Reynolds Number (Re) and the relative roughness of pipe (ε/D) were transformed to logarithmic scales. ...

  3. Bondi flow revisited

    CERN Document Server

    Datta, Satadal

    2016-01-01

    Newtonian spherically symmetric transonic accretion has been studied by including the mass of the accreting matter, while considering the growth of the accretor itself to be negligibly small. A novel iterative method has been introduced to accomplish that task. It has been demonstrated that the inclusion of the mass of the fluid changes the critical properties of the flow as well as the topological phase portraits of the stationary integral solution.

  4. Computational Simulation of Blood Flow through Bileaflet Heart Valve Prostheses

    Science.gov (United States)

    Healy, Timothy; Sotiropoulos, Fotis; Yoganathan, Ajit

    2001-11-01

    Non-physiologic flow patterns and levels of turbulence caused by contemporary bileaflet mechanical heart valve (MHV) designs are believed to be partially responsible for thromboembolic complications caused by these valves. Presently, computer-based flow assessment is not employed as a design tool. Rather, CFD is used to understand flow dynamics under highly-specialized circumstances after a design has been selected and tested experimentally. The absence of CFD from the design-screening process is most likely due to undeveloped tools specific to the heart valve problem. CFD tools for assessing MHV flow performance should be efficient at simulating the fluid-structure interaction and the resulting leaflet motion. As the first stage in the development of MHV simulation tools, a high-accuracy Chimera solver was developed and tested for laminar flow through two bileaflet MHV designs. Steady and time-dependent simulations were performed providing the highest resolution simulations of three-dimensional MHV flow fields to date. Flow structures and time-dependent flow phenomena were investigated and interpreted in the context of the clinical performance of each design studied.

  5. Conversational flow promotes solidarity.

    Directory of Open Access Journals (Sweden)

    Namkje Koudenburg

    Full Text Available Social interaction is fundamental to the development of various aspects of "we-ness". Previous research has focused on the role the content of interaction plays in establishing feelings of unity, belongingness and shared reality (a cluster of variables referred to as solidarity here. The present paper is less concerned with content, but focuses on the form of social interaction. We propose that the degree to which conversations flow smoothly or not is, of itself, a cue to solidarity. We test this hypothesis in samples of unacquainted and acquainted dyads who communicate via headsets. Conversational flow is disrupted by introducing a delay in the auditory feedback (vs. no delay. Results of three studies show that smoothly coordinated conversations (compared with disrupted conversations and a control condition increase feelings of belonging and perceptions of group entitativity, independently of conversation content. These effects are driven by the subjective experience of conversational flow. Our data suggest that this process occurs largely beyond individuals' control. We conclude that the form of social interaction is a powerful cue for inferring group solidarity. Implications for the impact of modern communication technology on developing a shared social identity are discussed.

  6. University cardiology clinic.

    Science.gov (United States)

    Borozanov, V

    2013-01-01

    In distant 1972, within framework of the Internal Clinic, a cardiologic department was organized which was soon, on 29.XII.1974, transformed into the Cardiology Clinic, later the Institute for Heart Diseases, and in 2008 was renamed the University Cardiology Clinic. The greater part of its foundation was possible owing to Prof. Dimitar Arsov and Prof. Radovan Percinkovski, who was the clinic's first director in the period from 1974 to 1984. In 1985, the Clinic moved into its own new building, and in that way was physically detached from the Internal Clinics. Until its move to the new building, the Clinic functioned in the Internal Clinics building, organized as an outpatient polyclinic and inpatient infirmary department with clinical beds, a coronary intensive care unit and a haemodynamics laboratory equipped with the most modern equipment of that time. Today the Clinic functions through two integral divisions: an inpatient infirmary department which comprises an intensive coronary care unit and fourteen wards which altogether have 139 clinical beds, and the diagnostic centre which comprises an emergency clinic and day hospital, a communal and consultative outpatients' clinic functioning on a daily basis, through which some 300-350 patients pass every day, and diagnostic laboratories with a capacity of nearly 100 non-invasive and 20-30 invasive diagnostic procedures daily. The Clinic is a teaching base, and its doctors are educators of students at the Medical, Dental and Pharmacy Faculties, and also of students at the High School for Nurses and X-ray technicians, but also for those in Internal Medicine and especially Cardiology. The Clinic is also a base for scientific Masters' and post-doctoral studies, and such higher degrees are achieved not only by doctors who work here, but also by doctors from Medical Centres both in the country and abroad. Doctors working in this institution publish widely, not only a great number of books and monographs, but also original

  7. Vortex shedding flow meter performance at high flow velocities

    Science.gov (United States)

    Siegwarth, J. D.

    1986-01-01

    In some of the ducts of the Space Shuttle Main Engine (SSME), the maximum liquid oxygen flow velocities approach 10 times those at which liquid flow measurements are normally made. The hydrogen gas flow velocities in other ducts exceed the maximum for gas flow measurement by more than a factor of 3. The results presented here show from water flow tests that vortex shedding flow meters of the appropriate design can measure water flow to velocities in excess of 55 m/s, which is a Reynolds number of about 2 million. Air flow tests have shown that the same meter can measure flow to a Reynolds number of at least 22 million. Vortex shedding meters were installed in two of the SSME ducts and tested with water flow. Narrow spectrum lines were obtained and the meter output frequencies were proportional to flow to + or - 0.5% or better over the test range with no flow conditioning, even though the ducts had multiple bends preceeding the meter location. Meters with the shedding elements only partially spanning the pipe and some meters with ring shaped shedding elements were also tested.

  8. Influence of the mean flow on zonal flow generation

    OpenAIRE

    Lashkin, V. M.

    2008-01-01

    Excitation of zonal flow by the modulational instability in the presence of mean shear flow is considered. It is shown that the small amplitude mean flow favours the modulational instability, increasing the growth rate, whereas sufficiently strong mean shear significantly reduces the instability growth rate.

  9. A multi-agent system for monitoring patient flow.

    Science.gov (United States)

    Rosati, Samanta; Tralli, Augusta; Balestra, Gabriella

    2013-01-01

    Patient flow within a healthcare facility may follow different and, sometimes, complicated paths. Each path phase is associated with the documentation of the activities carried out during it and may require the consultation of clinical guidelines, medical literature and the use of specific software and decision aid systems. In this study we present the design of a Patient Flow Management System (PFMS) based on Multi Agent Systems (MAS) methodology. System requirements were identified by means of process modeling tools and a MAS consisting of six agents was designed and is under construction. Its main goal is to support both the medical staff during the health care process and the hospital managers in assuring that all the required documentation is completed and available. Moreover, such a tool can be used for the assessment and comparison of different clinical pathways, in order to identify possible improvementsand the optimum patient flow.

  10. A multi-agent system for monitoring patient flow.

    Science.gov (United States)

    Rosati, Samanta; Tralli, Augusta; Balestra, Gabriella

    2013-01-01

    Patient flow within a healthcare facility may follow different and, sometimes, complicated paths. Each path phase is associated with the documentation of the activities carried out during it and may require the consultation of clinical guidelines, medical literature and the use of specific software and decision aid systems. In this study we present the design of a Patient Flow Management System (PFMS) based on Multi Agent Systems (MAS) methodology. System requirements were identified by means of process modeling tools and a MAS consisting of six agents was designed and is under construction. Its main goal is to support both the medical staff during the health care process and the hospital managers in assuring that all the required documentation is completed and available. Moreover, such a tool can be used for the assessment and comparison of different clinical pathways, in order to identify possible improvementsand the optimum patient flow. PMID:23920718

  11. Quantitative myocardial blood flow with Rubidium-82 PET

    DEFF Research Database (Denmark)

    Hagemann, Christoffer E; Ghotbi, Adam A; Kjær, Andreas;

    2015-01-01

    Positron emission tomography (PET) allows assessment of myocardial blood flow in absolute terms (ml/min/g). Quantification of myocardial blood flow (MBF) and myocardial flow reserve (MFR) extend the scope of conventional semi-quantitative myocardial perfusion imaging (MPI): e.g. in 1) identificat......Positron emission tomography (PET) allows assessment of myocardial blood flow in absolute terms (ml/min/g). Quantification of myocardial blood flow (MBF) and myocardial flow reserve (MFR) extend the scope of conventional semi-quantitative myocardial perfusion imaging (MPI): e.g. in 1...... pretest probability of CAD can support the clinical decision-making in treatment of CAD patients as a complementary tool to the invasive coronary angiography (CAG). Recently, several studies have proven Rubidium-82 ((82)Rb) PET's long-term prognostic value by a significant association between compromised...... global MFR and major adverse cardiovascular events (MACE), and together with new diagnostic possibilities from measuring the longitudinal myocardial perfusion gradient, cardiac (82)Rb PET faces a promising clinical future. This article reviews current evidence on quantitative (82)Rb PET's ability...

  12. Virtual Flow Simulator

    Energy Technology Data Exchange (ETDEWEB)

    2015-10-05

    Virtual Flow Simulator (VFS) is a state-of-the-art computational fluid mechanics (CFD) package that is capable of simulating multi-physics/multi-phase flows with the most advanced turbulence models (RANS, LES) over complex terrains. The flow solver is based on the Curvilinear Immersed Boundary (CURVIB) method to handle geometrically complex and moving domains. Different modules of the VFS package can provide different simulation capabilities for specific applications ranging from the fluid-structure interaction (FSI) of solid and deformable bodies, the two-phase free surface flow solver based on the level set method for ocean waves, sediment transport models in rivers and the large-scale models of wind farms based on actuator lines and surfaces. All numerical features of VFS package have been validated with known analytical and experimental data as reported in the related journal articles. VFS package is suitable for a broad range of engineering applications within different industries. VFS has been used in different projects with applications in wind and hydrokinetic energy, offshore and near-shore ocean studies, cardiovascular and biological flows, and natural streams and river morphodynamics. Over the last decade, the development of VFS has been supported and assisted with the help of various United States companies and federal agencies that are listed in the sponsor lists. In this version, VFS-Wind contains all the necessary modeling tools for wind energy applications, including land-based and offshore wind farms. VFS is highly scalable to run on either desktop computers or high performance clusters (up to 16,000 CPUs). This released version comes with a detailed user’s manual and a set of case studies designed to facilitate the learning of the various aspects of the code in a comprehensive manner. The included documentation and support material has been elaborated in a collaboration effort with Sandia National Labs under the contract DE-EE0005482. The VFS

  13. Asymmetric reactions in continuous flow

    Directory of Open Access Journals (Sweden)

    Xiao Yin Mak

    2009-04-01

    Full Text Available An overview of asymmetric synthesis in continuous flow and microreactors is presented in this review. Applications of homogeneous and heterogeneous asymmetric catalysis as well as biocatalysis in flow are discussed.

  14. Radial flow pulse jet mixer

    Science.gov (United States)

    VanOsdol, John G.

    2013-06-25

    The disclosure provides a pulse jet mixing vessel for mixing a plurality of solid particles. The pulse jet mixing vessel is comprised of a sludge basin, a flow surface surrounding the sludge basin, and a downcoming flow annulus between the flow surface and an inner shroud. The pulse jet mixing vessel is additionally comprised of an upper vessel pressurization volume in fluid communication with the downcoming flow annulus, and an inner shroud surge volume separated from the downcoming flow annulus by the inner shroud. When the solid particles are resting on the sludge basin and a fluid such as water is atop the particles and extending into the downcoming flow annulus and the inner shroud surge volume, mixing occurs by pressurization of the upper vessel pressurization volume, generating an inward radial flow over the flow surface and an upwash jet at the center of the sludge basin.

  15. A Cryogenic Flow Sensor Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Based on the success of the phase I effort, Advanced Technologies Group, Inc. proposes the development of a Cryogenic Flow Sensor (CFS) for determining mass flow of...

  16. Characteristics of Solar Meridional Flows

    Science.gov (United States)

    Basu, Sarbani; Antia, H. M.

    2011-01-01

    We have done a ring-diagram analysis of MDI full-disc data to determine the properties of solar meridional flow in the outer 2% of the Sun over the solar cycle 23. The meridional flows show a migrating pattern with higher-velocity flows migrating toward the equator as activity increases. Additionally, we find that the migrating pattern of the meridional flow matches those of the sunspot butterfly diagram and the zonal flows in the shallow layers. A Legendre polynomial decomposition of the meridional flows shows that the latitudinal pattern of the flow was also different during the maximum as compared to that during the two minima. We also find that the dominant component of the meridional flows during solar maxima was much lower than that during the minima of solar cycles 23 and 24.

  17. Clinical Process Intelligence

    DEFF Research Database (Denmark)

    Vilstrup Pedersen, Klaus

    2006-01-01

    knowledge to the point of care in a proactive manner. Attention has been on the translation of guidelines and the integration with the elec-tronic medical record (EMR). Less attention has been paid to the evaluation of clinical practice in relation to clinical guide-lines. I claim that single patient cases......, generalized processes de-ducted from many patient cases and clinical guidelines, are all guidelines that may be used in clinical reasoning. The differ-ence is the validity of the suggested actions and decisions. In the case of generalized processes deducted from EMRs, we have "what we usually do" practice i......Ideally, clinical guidelines are created from evidence based medicine. Translating the narrative semi-structured article for-mat of the clinical guidelines into a computable language makes it possible to utilize this information in IT-supported clinical reasoning, and thereby bring the relevant...

  18. Learning clinical reasoning.

    Science.gov (United States)

    Pinnock, Ralph; Welch, Paul

    2014-04-01

    Errors in clinical reasoning continue to account for significant morbidity and mortality, despite evidence-based guidelines and improved technology. Experts in clinical reasoning often use unconscious cognitive processes that they are not aware of unless they explain how they are thinking. Understanding the intuitive and analytical thinking processes provides a guide for instruction. How knowledge is stored is critical to expertise in clinical reasoning. Curricula should be designed so that trainees store knowledge in a way that is clinically relevant. Competence in clinical reasoning is acquired by supervised practice with effective feedback. Clinicians must recognise the common errors in clinical reasoning and how to avoid them. Trainees can learn clinical reasoning effectively in everyday practice if teachers provide guidance on the cognitive processes involved in making diagnostic decisions.

  19. 4-D flow magnetic resonance imaging: blood flow quantification compared to 2-D phase-contrast magnetic resonance imaging and Doppler echocardiography

    Energy Technology Data Exchange (ETDEWEB)

    Gabbour, Maya [Ann and Robert H. Lurie Children' s Hospital of Chicago, Department of Medical Imaging 9, Chicago, IL (United States); Schnell, Susanne [Northwestern University Feinberg School of Medicine, Department of Radiology, Chicago, IL (United States); Jarvis, Kelly [Northwestern University, Department of Biomedical Engineering, McCormick School of Engineering, Evanston, IL (United States); Robinson, Joshua D. [Ann and Robert H. Lurie Children' s Hospital of Chicago, Department of Pediatrics, Division of Pediatric Cardiology, Chicago, IL (United States); Northwestern University Feinberg School of Medicine, Department of Pediatrics, Chicago, IL (United States); Markl, Michael [Northwestern University Feinberg School of Medicine, Department of Radiology, Chicago, IL (United States); Northwestern University, Department of Biomedical Engineering, McCormick School of Engineering, Evanston, IL (United States); Rigsby, Cynthia K. [Ann and Robert H. Lurie Children' s Hospital of Chicago, Department of Medical Imaging 9, Chicago, IL (United States); Northwestern University Feinberg School of Medicine, Department of Radiology, Chicago, IL (United States)

    2015-06-15

    Doppler echocardiography (echo) is the reference standard for blood flow velocity analysis, and two-dimensional (2-D) phase-contrast magnetic resonance imaging (MRI) is considered the reference standard for quantitative blood flow assessment. However, both clinical standard-of-care techniques are limited by 2-D acquisitions and single-direction velocity encoding and may make them inadequate to assess the complex three-dimensional hemodynamics seen in congenital heart disease. Four-dimensional flow MRI (4-D flow) enables qualitative and quantitative analysis of complex blood flow in the heart and great arteries. The objectives of this study are to compare 4-D flow with 2-D phase-contrast MRI for quantification of aortic and pulmonary flow and to evaluate the advantage of 4-D flow-based volumetric flow analysis compared to 2-D phase-contrast MRI and echo for peak velocity assessment in children and young adults. Two-dimensional phase-contrast MRI of the aortic root, main pulmonary artery (MPA), and right and left pulmonary arteries (RPA, LPA) and 4-D flow with volumetric coverage of the aorta and pulmonary arteries were performed in 50 patients (mean age: 13.1 ± 6.4 years). Four-dimensional flow analyses included calculation of net flow and regurgitant fraction with 4-D flow analysis planes similarly positioned to 2-D planes. In addition, 4-D flow volumetric assessment of aortic root/ascending aorta and MPA peak velocities was performed and compared to 2-D phase-contrast MRI and echo. Excellent correlation and agreement were found between 2-D phase-contrast MRI and 4-D flow for net flow (r = 0.97, P < 0.001) and excellent correlation with good agreement was found for regurgitant fraction (r = 0.88, P < 0.001) in all vessels. Two-dimensional phase-contrast MRI significantly underestimated aortic (P = 0.032) and MPA (P < 0.001) peak velocities compared to echo, while volumetric 4-D flow analysis resulted in higher (aortic: P = 0.001) or similar (MPA: P = 0.98) peak

  20. Critical flow in the pipes

    International Nuclear Information System (INIS)

    On the basis of the homogeneous flow model and by using the basis constitutive equations describing the two-phase flow, the difference equation groups for calculating two-phase critical flow are derived. The influence of the changes of section, heat exchanges and so on the critical flow are considered. When the exit steam qualities are less than 0.1 or greater than 0.75 in the pipe line systems, this method is adapted to use

  1. Traffic flow modeling: a Genealogy

    OpenAIRE

    Van Wageningen-Kessels, F.L.M.; Hoogendoorn, S.P.; Vuik, C.; Lint, van J. W. C.

    2014-01-01

    80 years ago, Bruce Greenshields presented the first traffic flow model at the Annual Meeting of the Highway Research Board. Since then, many models and simulation tools have been developed. We show a model tree with four families of traffic flow models, all descending from Greenshields' model. The tree shows the historical development of traffic flow modeling and the relations between models. Based on the tree we discuss the main trends and future developments in traffic flow modeling and si...

  2. Longitudinal Vortices in Granular Flows

    OpenAIRE

    Forterre, Yoel; Pouliquen, Olivier

    2001-01-01

    We present a new instability observed in rapid granular flows down rough inclined planes. For high inclinations and flow rates, the free surface of the flow experiences a regular deformation in the transverse direction. Measurements of the surface velocities imply that this instability is associated with the formation of longitudinal vortices in the granular flow. From the experimental observations, we propose a mechanism for the longitudinal vortex formation based on the concept of granular ...

  3. Developments in redox flow batteries

    OpenAIRE

    Tangirala, Ravichandra

    2011-01-01

    This thesis describes the investigation of the electrochemistry principles, technology, construction and composition of the electrode materials, electrolyte and additives used in redox flow batteries. The aim was to study a flow battery system with an appreciable working performance. The study explores and compares mainly three different redox flow battery technologies; all-vanadium, soluble lead-acid and a novel copper-lead dioxide flow batteries. The first system is based in sulfuric acid e...

  4. Bulk flow scaling for turbulent channel and pipe flows

    CERN Document Server

    Chen, Xi; She, Zhen-Su

    2016-01-01

    We report a theory deriving bulk flow scaling for canonical wall-bounded flows. The theory accounts for the symmetries of boundary geometry (flat plate channel versus circular pipe) by a variational calculation for a large-scale energy length, which characterizes its bulk flow scaling by a simple exponent, i.e. $m=4$ for channel and 5 for pipe. The predicted mean velocity shows excellent agreement with several dozen sets of quality empirical data for a wide range of the Reynolds number (Re), with a universal bulk flow constant $\\kappa\\approx0.45$. Predictions for dissipation and turbulent transport in the bulk flow are also given, awaiting data verification.

  5. Flow around a line obstacle

    NARCIS (Netherlands)

    Jacobs, A.F.G.

    1983-01-01

    Shear layer flows which are strongly disturbed, often occur in nature as well as in engineering practice. Up to now little is known about this class of flows. This is Partly explained by the complexity of these flows and partly by a lack of experimental data. The objective of this study is: first, t

  6. Liquid/Gas Flow Mixers

    Science.gov (United States)

    Fabris, Gracio

    1994-01-01

    Improved devices mix gases and liquids into bubbly or foamy flows. Generates flowing, homogeneous foams or homogeneous dispersions of small, noncoalescing bubbles entrained in flowing liquids. Mixers useful in liquid-metal magnetohydrodynamic electric-power generator, froth flotation in mining industry, wastewater treatment, aerobic digestion, and stripping hydrocarbon contaminants from ground water.

  7. Integrating clinical research into clinical decision making

    Directory of Open Access Journals (Sweden)

    Mark R Tonelli

    2011-01-01

    Full Text Available Evidence-based medicine has placed a general priority on knowledge gained from clinical research for clinical decision making. However, knowledge derived from empiric, population-based research, while valued for its ability to limit bias, is not directly applicable to the care of individual patients. The gap between clinical research and individual patient care centers on the fact that empiric research is not generally designed to answer questions of direct relevance to individual patients. Clinicians must utilize other forms of medical knowledge, including pathophysiologic rationale and clinical experience, in order to arrive at the best medical decision for a particular patient. In addition, clinicians must also elucidate and account for the goals and values of individual patients as well as barriers and facilitators of care inherent in the system in which they practice. Evidence-based guidelines and protocols, then, can never be prescriptive. Clinicians must continue to rely on clinical judgment, negotiating potentially conflicting warrants for action, in an effort to arrive at the best decision for a particular patient.

  8. Everting (toposcopic) catheter for broad clinical application.

    Science.gov (United States)

    Shook, D R; Doppman, J L; Cattau, E L; Goldstein, S R

    1986-05-01

    The advanced development of the clinical everting (toposcopic) catheter is described. A detailed discussion of the design and outline of the fabrication techniques are followed by a thorough performance evaluation and summary of the first two clinical applications. The everting element is a low-durometer thermoplastic polyurethane elastomer. Surface treatments include the bonding of a hydrophilic polymeric coating, optimized for lubricity, to the sliding internal surfaces of the catheter. Eversion pressures and infusion/aspiration flow rates have been measured under various conditions and the infusate-in-blood mixing potential investigated. A preliminary assessment is given of the clinical performance of the catheter in the vascular delivery of chemotherapy and standard endoscopic retrograde cholangiopancreatography. PMID:3724105

  9. Online traffic flow model applying dynamic flow-density relation

    CERN Document Server

    Kim, Y

    2002-01-01

    This dissertation describes a new approach of the online traffic flow modelling based on the hydrodynamic traffic flow model and an online process to adapt the flow-density relation dynamically. The new modelling approach was tested based on the real traffic situations in various homogeneous motorway sections and a motorway section with ramps and gave encouraging simulation results. This work is composed of two parts: first the analysis of traffic flow characteristics and second the development of a new online traffic flow model applying these characteristics. For homogeneous motorway sections traffic flow is classified into six different traffic states with different characteristics. Delimitation criteria were developed to separate these states. The hysteresis phenomena were analysed during the transitions between these traffic states. The traffic states and the transitions are represented on a states diagram with the flow axis and the density axis. For motorway sections with ramps the complicated traffic fl...

  10. Flow choking over weir flow slit-type flip buckets

    Institute of Scientific and Technical Information of China (English)

    马飞; 徐准; 吴建华

    2015-01-01

    The flow choking may occur for weir flow slit-type flip buckets under common operation conditions. An estimation method is developed through introducing a comprehensive coefficient to determine the approach flow Froude number for the flow choking to occur in those flip buckets. The error of the present method relative to the experimental data is less than 5%. The results show that, the Froude number for the flow choking to occur is related to the contraction ratio and the contraction angle of the flip buckets. When the flow choking occurs, the upper jet trajectory decreases and the lower one is almost not affected, and the dynamic pressures on the bottom and the sidewalls increase due to the flow profile rising on the flip buckets.

  11. Low-cost laser speckle contrast imaging of blood flow using a webcam

    OpenAIRE

    Richards, Lisa M.; Kazmi, S. M. Shams; Davis, Janel L.; Olin, Katherine E.; Dunn, Andrew K.

    2013-01-01

    Laser speckle contrast imaging has become a widely used tool for dynamic imaging of blood flow, both in animal models and in the clinic. Typically, laser speckle contrast imaging is performed using scientific-grade instrumentation. However, due to recent advances in camera technology, these expensive components may not be necessary to produce accurate images. In this paper, we demonstrate that a consumer-grade webcam can be used to visualize changes in flow, both in a microfluidic flow phanto...

  12. Coronary artery ectasia and systolic flow cessation in a patient with hypertrophic cardiomyopathy: a case report.

    Science.gov (United States)

    Zografos, Theodoros; Kokladi, Maria; Katritsis, Demosthenes

    2010-12-01

    Coronary artery ectasia (CAE) is characterized by diffuse or localized inappropriate dilation of coronary arteries and is often associated with slow coronary blood flow. Although CAE has been described to coexist with several clinical entities there are only three reports of CAE in the presence of hypertrophic cardiomyopathy (HCM). We report a case of CAE and slow coronary flow with systolic flow cessation in a 61-year old male with coronary artery disease and HCM.

  13. Analysis of tidal expiratory flow pattern in the assessment of histamine-induced bronchoconstriction.

    OpenAIRE

    Morris, M. J.; Madgwick, R. G.; Lane, D. J.

    1995-01-01

    BACKGROUND--There are times in clinical practice when it would be useful to be able to assess the severity of airways obstruction from tidal breathing. Three indices of airways obstruction derived from analysis of resting tidal expiratory flow have previously been described: (1) Tme/TE = time to reach maximum expiratory flow/expiratory time; (2) Krs = decay constant of exponential fitted to tidal expiratory flow versus time curve; and (3) EV = extrapolated volume--that is, area under the curv...

  14. In vitro and in vivo studies of pulmonary artery flow

    International Nuclear Information System (INIS)

    A variety of interesting intracardiac flow patterns have been recorded by pulsed and continuous wave Doppler technologies in humans with heart disease. Some of these patterns have, in fact, been difficult to explain and are now more easily understood using color Doppler flow mapping systems which show the spatial location of flow. The authors performed a number of studies in patients, as well as studies in in vitro systems to model some of the phenomenon that the authors observed in the pulmonary artery. Their studies with Doppler flow mapping in the clinical situation, in the in vitro model, and in the animal models of congenital heart disorders lend insights into the complex hydrodynamics present in the pulmonary artery

  15. Skeletal Blood Flow in Bone Repair and Maintenance

    Institute of Scientific and Technical Information of China (English)

    Ryan E.Tomlinson; Matthew J.Silva

    2013-01-01

    Bone is a highly vascularized tissue, although this aspect of bone is often overlooked. In this article, the importance of blood flow in bone repair and regeneration will be reviewed. First, the skeletal vascular anato-my, with an emphasis on long bones, the distinct mechanisms for vascularizing bone tissue, and methods for remodeling existing vasculature are discussed. Next, techniques for quantifying bone blood flow are briefly summarized. Finally, the body of experimental work that demonstrates the role of bone blood flow in fracture healing, distraction osteogenesis, osteoporosis, disuse osteopenia, and bone grafting is examined. These results illustrate that adequate bone blood flow is an important clinical consideration, particularly during bone regeneration and in at-risk patient groups.

  16. Hydrology and flow forecasting

    OpenAIRE

    Pang, H; Rao, S.Q.; G. Q. Wang; Huang, X. Q.

    2002-01-01

    We have studied and applied the statistic model (i.e. MMC) and hydrological models to Upper Yellow River. This report introduces the results and some conclusions from the model. The three models, MMC, MWBM and NAM, have be applied in the research area. The forecasted discharge by the three models are closed to the recorded in most low flow months, but in some flood months, the forecasted value is much different with recorded one. And forecasted accuracy by MWBM nearly matches with that by NAM...

  17. Providing Compassion through Flow

    Directory of Open Access Journals (Sweden)

    Lydia Royeen

    2015-07-01

    Full Text Available Meg Kral, MS, OTR/L, CLT, is the cover artist for the Summer 2015 issue of The Open Journal of Occupational Therapy. Her untitled piece of art is an oil painting and is a re-creation of a photograph taken while on vacation. Meg is currently supervisor of outpatient services at Rush University Medical Center. She is lymphedema certified and has a specific interest in breast cancer lymphedema. Art and occupational therapy serve similar purposes for Meg: both provide a sense of flow. She values the outcomes, whether it is a piece of art or improved functional status

  18. Flow in journalistic telework.

    Science.gov (United States)

    Manssour, Ana Beatriz Benites

    2003-02-01

    Since the 1980s, the strengthening and dissemination of telework has motivated studies to verify its advantages and disadvantages to enterprises and workers, specially focusing on economy, quality, and productivity performances. This paper developed from a master's thesis research which analyzed the subjective impact of telework concerning workers' personal satisfaction, their perception about suffering and pleasure when developing their work activities and social interrelationships, and, particularly, the influence it could have in their maximum experiences, the flow. Considering that the press media represents a historical telework, it was chosen as the research focus, selecting columnists from a large newspaper, located in the Brazilian south region. PMID:12650561

  19. Let It Flow

    Institute of Scientific and Technical Information of China (English)

    Alphonce; Shiundu

    2011-01-01

    Ghana’s Jubilee oilfield output projected to more than double by year-end AFRICA’S Gold Coast,otherwise known as the Republic of Ghana,marked the first 100 days since its oil taps began running,on March 25,2011.The oil in question flows from the country’s offshore Jubilee oilfield, recognized by the stakeholders to be the largest oil discovery in West Africa in the last 10 to 15 years. This discovery has injected an air of optimism amongst Ghana-

  20. Children and Clinical Studies: Why Clinical Studies Are Important

    Medline Plus

    Full Text Available ... NHLBI Trials Clinical Trial Websites Children and Clinical Studies Learn more about Children and Clinical Studies Importance of Children in Clinical Studies Children have often had to accept medicines and ...

  1. Flow in air conditioned rooms

    DEFF Research Database (Denmark)

    Nielsen, Peter V.

    1974-01-01

    Flow in air conditioned r ooms is examined by means of model experiments . The different gearnetries giving unsteady, steady three- dimensional and steady twodimensional flow are determined . Velacity profiles and temperature profiles are measured in some of the geometries. A numerical solution...... of the flow equations is demonstrated and the flow in air conditioned rooms in case of steady two dimensional flow is predi cted. Compari son with measured results is shown i n the case of small Archimedes numbers, and predictions are shown at high Archimedes numbers. A numerical prediction of f low and heat...

  2. Heat exchanger with oscillating flow

    Science.gov (United States)

    Scotti, Stephen J. (Inventor); Blosser, Max L. (Inventor); Camarda, Charles J. (Inventor)

    1993-01-01

    Various heat exchange apparatuses are described in which an oscillating flow of primary coolant is used to dissipate an incident heat flux. The oscillating flow may be imparted by a reciprocating piston, a double action twin reciprocating piston, fluidic oscillators or electromagnetic pumps. The oscillating fluid flows through at least one conduit in either an open loop or a closed loop. A secondary flow of coolant may be used to flow over the outer walls of at least one conduit to remove heat transferred from the primary coolant to the walls of the conduit.

  3. Minimal flows and their extensions

    CERN Document Server

    Auslander, J

    1988-01-01

    This monograph presents developments in the abstract theory of topological dynamics, concentrating on the internal structure of minimal flows (actions of groups on compact Hausdorff spaces for which every orbit is dense) and their homomorphisms (continuous equivariant maps). Various classes of minimal flows (equicontinuous, distal, point distal) are intensively studied, and a general structure theorem is obtained. Another theme is the ``universal'' approach - entire classes of minimal flows are studied, rather than flows in isolation. This leads to the consideration of disjointness of flows, w

  4. Flow tracing based on current

    Institute of Scientific and Technical Information of China (English)

    蔡兴国; 曹海龙

    2001-01-01

    Analyses the flow tracing based on power flow, points out that the detachment of reactive power and active power is unrealiable and concludes that the current is the real basic of flow tracing,and proposes the new flow tracing model based on current, which devides the current into active current and reactive current, analyses the theory about the matrix to deal with the precision and realization of the flow tracing, and then proposes a new pricing model by fixed rate and marginal rate, which keeps not only economy information such as congestion cost in marginal cost based pricing, but also benefits to make both ends meet.

  5. Clinical aspects of venous thrombophilia.

    Science.gov (United States)

    Girolami, Antonio; Fabris, Fabrizio; Girolami, Bruno

    2002-01-01

    Venous thrombophilia is the result of clotting changes namely of a hypercoagulable state together with blood flow and vessel wall changes. There is no need for all these components to be present in order for thrombosis to occur. As the matter of fact, thrombosis may occur even if only one of these conditions is present. In clinical practice a combination of factors is usualy seen. In comparison with arterial thrombophilia, clotting changes and blood flow seen to play a major role in venous thrombosis. Venous thrombophilia may remain asynptomatic or may result in a series of clinical syndromes. The commonest of these are: 1. Superficial vein thrombosis, 2. Deep vein thrombosis of legs, 3. Deep vein thrombosis of arms, 4. Caval veins thrombosis, 5. Portal vein thrombosis, 6. Hepatic veins thrombosis, 7. Renal vein thrombosis, 8. Cerebral sinuses thrombosis, 9. Right heart thrombosis, 10. Miscellaneous (ovarian, adrenal veins thrombosis, etc.). Since the first two are widely and easily recognized, these is no need for an extensive discussion. Deep vein thromboses of upper limbs are not as frequent as those of lower limbs or of superficial phlebitis but they can still be recognized on clinical grounds and non invasive techniques. The remaining 7 syndromes are less common and therefore less frequently suspected and recognized. Of particular interest, among these less common manifestations of venous thrombophilia are hepatic vein and renal vein thrombosis. Hepatic veins thrombosis, sometimes part of inferior vena cava thrombosis is most frequently due to an isolated occlusion of hepatic veins thereby causing a form of venocclusive disease. Occasionally diagnosis may be difficult because of slow onset of symptoms (hepatomegaly, right flank pain, fever, ascites etc.). The same is true for renal vein thrombosis which may also be of difficult diagnosis since it causes proteinuria and flank pain. The proteinuria is often interpreted as due to a nephrotic syndrome which

  6. Numerical simulation of steady flow fields in coiled flow inverter

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, Vimal; Nigam, K.D.P. [Department of Chemical Engineering, Indian Institute of Technology, Delhi, Hauz Khas, New Delhi 110 016 (India)

    2005-11-01

    Flatter velocity profiles and more uniform thermal environments are extremely desirous factors for improved performance in flow reactors and heat exchangers. One means of achieving it in laminar flow systems is to use mixers and flow inverters. In the present study a new device is introduced based on the flow inversion by changing the direction of centrifugal force in helically coiled tubes. The objective of the present study is to characterize flow development and temperature fields in the proposed device made up from the configurations of bent coils. The main mechanism generating the flow is the production of spatially chaotic path by changing the direction of flow using a 90{sup o} bend in helical coils (alternating Dean flow). If the direction of centrifugal force is rotated by any angle, the plane of vortex formation also rotates with the same angle. Thus in helical flow a 90{sup o} shift in the direction of centrifugal force cause a complete flow inversion. Complete flow fields and thermal fields in helical coil and bent coil configuration were studied using computational fluid dynamics software (FLUENT 6.0). The three-dimensional governing equations for momentum and energy under the laminar flow conditions were solved with a control-volume finite difference method (CVFDM) with second-order accuracy. The flow pattern obtained for the helical coil was in good agreement to those observed by the previous investigators [S.W. Jones, O.M. Thomas, H. Aref, Chaotic advection by laminar flow in twisted pipe. J. Fluid Mech. 209 (1989) 335-357; Ch. Duchene, H. Peerhossaini, P.J. Michard, On the velocity field and tracer patterns in a twisted duct flow. Phys. Fluids 7 (1995) 1307-1317]. The comparison of the flow fields and temperature fields in the helical tube and bent coil configuration are discussed. The bent coil configuration shows a 20-30% enhancement in the heat transfer due to chaotic mixing while relative pressure drop is 5-6%. The results of the present study

  7. Experimental investigation of cavity flows

    Energy Technology Data Exchange (ETDEWEB)

    Loeland, Tore

    1998-12-31

    This thesis uses LDV (Laser Doppler Velocimetry), PIV (Particle Image Velocimetry) and Laser Sheet flow Visualisation to study flow inside three different cavity configurations. For sloping cavities, the vortex structure inside the cavities is found to depend upon the flow direction past the cavity. The shape of the downstream corner is a key factor in destroying the boundary layer flow entering the cavity. The experimental results agree well with numerical simulations of the same geometrical configurations. The results of the investigations are used to find the influence of the cavity flow on the accuracy of the ultrasonic flowmeter. A method to compensate for the cavity velocities is suggested. It is found that the relative deviation caused by the cavity velocities depend linearly on the pipe flow. It appears that the flow inside the cavities should not be neglected as done in the draft for the ISO technical report on ultrasonic flowmeters. 58 refs., 147 figs., 2 tabs.

  8. Monolithic Continuous-Flow Bioreactors

    Science.gov (United States)

    Stephanopoulos, Gregory; Kornfield, Julia A.; Voecks, Gerald A.

    1993-01-01

    Monolithic ceramic matrices containing many small flow passages useful as continuous-flow bioreactors. Ceramic matrix containing passages made by extruding and firing suitable ceramic. Pores in matrix provide attachment medium for film of cells and allow free movement of solution. Material one not toxic to micro-organisms grown in reactor. In reactor, liquid nutrients flow over, and liquid reaction products flow from, cell culture immobilized in one set of channels while oxygen flows to, and gaseous reaction products flow from, culture in adjacent set of passages. Cells live on inner surfaces containing flowing nutrient and in pores of walls of passages. Ready access to nutrients and oxygen in channels. They generate continuous high yield characteristic of immobilized cells, without large expenditure of energy otherwise incurred if necessary to pump nutrient solution through dense biomass as in bioreactors of other types.

  9. CME ON CLINICAL RESEARCH

    OpenAIRE

    Suneel. I. Majagi; S. S. Torgal; S. V. Hiremath

    2012-01-01

    Safety and efficacy are the two major concerns for any drug therapy. Globally clinical research plays an inevitable role in bringing a new molecule into the market after its synthesis by the pharmaceutical industries. Availability of large patient population, highly educated and skilled manpower, wide spectrum of diseases and favorable economic environment imply India’s potential as a global hub for clinical research. Pharmaceutical companies and Clinical Research Organization (CRO)s will req...

  10. Experimental study of flow artifact in MRI venous flow model

    International Nuclear Information System (INIS)

    Venous flow models were constructed and experiments were done on the signal generation from blood flow. MRI apparatus used was 1.0T Shimadzu SMT100. Images were constructed by 2D Fourrier conversion. The magnetic intensity was 1.5 mT/m. Continuous 6 slices of 10, 7 and 5 mm thickness were imaged in T2-weighted condition at TR 2500 msec and TE 90 msec by the spin echo method, rephasing method, presaturation method, rephasing + presaturation method and rephasing + presaturation + low sampling cycle method for flow rate and pulsatile flow. The artificial blood vessels were made of polychlorinated vinyl tube with inner diameter 8 mm x 20 m length where 40 litre of water was circulated at a fixed flow rate of 5-30 cm/sec or pulsatile flow rate of 15 and 20 cm/sec. A tube filled with Gd-DTPA solution was used as a control. S/N ratio in every slice of the fixed and pulsatile flows, the difference by the direction of imaging, the presence or absence of rephasing and presaturation and sampling cycles were examined. A significant flow artifact was found yielded for the pulsatile flow relative to the fixed flow. (K.H.)

  11. Experimental research of the couette flow with cross flow

    Science.gov (United States)

    Nobis, Matthias; Stücke, Peter; Schmidt, Marcus

    2012-04-01

    When a solid cylinder is rotating inside a hollow cylinder, a characteristic fluid flow occurs inside the gap between the two cylinders, caused by the adhesion of the fluid at the walls. This flow problem is widely known as the Couette-flow. If an additional flow entrances through a radial located feedhole at the outer hollow cylinder, there is an interaction between the cross flow and the Couette-flow. In result there are complex three dimensional flow structures in the gap at the area around the feedhole. These arising flow structures are closely related with the technical important flow inside the gap of hydrodynamic lubricated journal bearings. When the flow conditions inside the bearing gap are well explored and appreciated, it will be possible to give suggestions for constructive details like the design, the location and the dimension of the feedhole for longer lifecycles or an even more efficiently running. In this paper the test rig of the bearing model will be presented. Moreover some representative results from researches with a Laser-Doppler-Velocimeter (LDV) in comparison with the output of three dimensional numerical simulations will be illustrated.

  12. AC Optimal Power Flow

    Energy Technology Data Exchange (ETDEWEB)

    2016-10-04

    In this work, we have implemented and developed the simulation software to implement the mathematical model of an AC Optimal Power Flow (OPF) problem. The objective function is to minimize the total cost of generation subject to constraints of node power balance (both real and reactive) and line power flow limits (MW, MVAr, and MVA). We have currently implemented the polar coordinate version of the problem. In the present work, we have used the optimization solver, Knitro (proprietary and not included in this software) to solve the problem and we have kept option for both the native numerical derivative evaluation (working satisfactorily now) as well as for analytical formulas corresponding to the derivatives being provided to Knitro (currently, in the debugging stage). Since the AC OPF is a highly non-convex optimization problem, we have also kept the option for a multistart solution. All of these can be decided by the user during run-time in an interactive manner. The software has been developed in C++ programming language, running with GCC compiler on a Linux machine. We have tested for satisfactory results against Matpower for the IEEE 14 bus system.

  13. Data flow computing

    International Nuclear Information System (INIS)

    In the design of supercomputer systems, anticipated needs and available technology play a crucial role. Most current approaches start from the same basic technology premise: advances in VLSI represent a significant improvement in hardware components than can produce valuable gains in the cost/performance ratios of new systems. The key to this cost/performance ratio is replication of relatively cheap components. Hence, almost all the current supercomputer designs are multiprocessors. The critical question becomes, how can a designer organize them for effective problem solving? Here, different user needs have led to research into several design strategies. Consider, for example, the needs of a ballistic missile defense system. This application requires real-time response and processing of large amounts of data that can be received at very uneven rates. For cost/effectiveness, the best computer system would automatically adjust to the current nature and demands of the computing load placed on it. Dynamically reconfigurable architectures address this type of application. As another example, consider the problem of monitoring and controlling a large nuclear reactor. In this case, real-time response is still important. However, reconfiguration may not be so crucial because monitoring sensors receive a relatively steady flow of data to process. A dedicated computer system may be more appropriate for this case. This chapter presents the data-flow computing strategy

  14. Air Traffic Flow Management

    CERN Document Server

    Ganu, Hrishikesh V

    2008-01-01

    Air Traffic Flow Management is the regulation of air traffic in order to avoid exceeding airport or flight sector capacity in handling traffic, and to ensure that available capacity is used efficiently. We have tried to explore the logic behind the claims by Bertsimas et.al about integral solutions to the LP relaxation of the Traffic Flow Management Problem(TFMP). Polyhedral theory only indicates that the stronger TFMP formulation of Bertsimas et.al might lead to integral solutions in some cases. Our computations indicate that the encouraging results reported by Bertsimas et.al are not merely fortuitous or due to their specific data set. Indeed, we found that the TFMP had integral solutions even in case of artificial data sets generated to include severe conflicts in the flight schedules. In our limited tests with 4-5 scenarios, we obtained non-integral solutions only once. This is of significant practical importance because, the LP relaxation can be solved even on small machines with low memory and processor...

  15. Blood flow measurement using a highly filled carbon polymer sandwich sensor and an elasto-pseudo compressible vascular flow.

    Science.gov (United States)

    Mehdian, M; Rahnejat, H

    1996-01-01

    Vascular grafts are widely employed in clinical practice and still pose significant problems of compatibility and longevity, particularly when the prosthesis is to replace arteries of small diameter. Once a graft has been implanted in the vascular tree, there is no easy way of assessing its interactions with the surrounding tissue. Doppler flow probes or some imaging techniques are commonly used to monitor flow velocity in vascular prostheses. It is, however, difficult to monitor a patient's recovery on a continuous basis. Continuous means of measurement can be quite invaluable. This paper presents a high-carbon filled polymer (HCFP) sensor that is developed for blood flow measurement in vascular grafts. Furthermore, a computational fluid dynamics model of incompressible blood flow in elastic blood vessels is presented. PMID:9046189

  16. Heart blood flow simulation: a perspective review.

    Science.gov (United States)

    Doost, Siamak N; Ghista, Dhanjoo; Su, Boyang; Zhong, Liang; Morsi, Yosry S

    2016-01-01

    Cardiovascular disease (CVD), the leading cause of death today, incorporates a wide range of cardiovascular system malfunctions that affect heart functionality. It is believed that the hemodynamic loads exerted on the cardiovascular system, the left ventricle (LV) in particular, are the leading cause of CVD initiation and propagation. Moreover, it is believed that the diagnosis and prognosis of CVD at an early stage could reduce its high mortality and morbidity rate. Therefore, a set of robust clinical cardiovascular assessment tools has been introduced to compute the cardiovascular hemodynamics in order to provide useful insights to physicians to recognize indicators leading to CVD and also to aid the diagnosis of CVD. Recently, a combination of computational fluid dynamics (CFD) and different medical imaging tools, image-based CFD (IB-CFD), has been widely employed for cardiovascular functional assessment by providing reliable hemodynamic parameters. Even though the capability of CFD to provide reliable flow dynamics in general fluid mechanics problems has been widely demonstrated for many years, up to now, the clinical implications of the IB-CFD patient-specific LVs have not been applicable due to its limitations and complications. In this paper, we review investigations conducted to numerically simulate patient-specific human LV over the past 15 years using IB-CFD methods. Firstly, we divide different studies according to the different LV types (physiological and different pathological conditions) that have been chosen to reconstruct the geometry, and then discuss their contributions, methodologies, limitations, and findings. In this regard, we have studied CFD simulations of intraventricular flows and related cardiology insights, for (i) Physiological patient-specific LV models, (ii) Pathological heart patient-specific models, including myocardial infarction, dilated cardiomyopathy, hypertrophic cardiomyopathy and hypoplastic left heart syndrome. Finally, we

  17. Clinical research informatics

    CERN Document Server

    Richesson, Rachel L

    2012-01-01

    This book provides foundational coverage of key areas, concepts, constructs, and approaches of medical informatics as it applies to clinical research activities, in both current settings and in light of emerging policies. The field of clinical research is fully characterized (in terms of study design and overarching business processes), and there is emphasis on information management aspects and informatics implications (including needed activities) within various clinical research environments. The purpose of the book is to provide an overview of clinical research (types), activities, and are

  18. Lava Flows in Eastern Tharsis

    Science.gov (United States)

    2002-01-01

    (Released 31 May 2002) This image may at first appear somewhat bland -- there is little contrast in the surface materials due to dust cover, and there are few impact craters -- but there are some very interesting geologic features here. The great Tharsis volcanoes have produced vast fields of lava flows, such as those shown in this image, to the east of Tharsis Tholus. The flows in this image have moved from west to east, down the regional topographic slope. The lobate edges of the flows are distinctive, and permit the discrimination of many overlapping individual flows that may represent tens, hundreds, thousands, or even millions of years worth of volcanic activity (overlapping relationships are especially evident at the bottom of the image). Viewed at full resolution, the image reveals interesting patterns and textures on the top surfaces of these flows. In particular, at the top of the image, there are numerous parallel curved ridges visible on the upper surfaces of the lava flows. These ridges make the flow surface look somewhat ropy, and at smaller scales this flow might be referred to as pahoehoe, indicative of a relatively fluid type of lava flow. At the scales observed here, however, these features are probably better referred to as pressure ridges. Pressure ridges form on the surface of a lava flow when the upper part of the flow is exposed to air, freezing it, but the insulated unfrozen interior of the flow continues to move down slope (and more material is pushed forward from behind), causing the surface to compress and pile up like a rug. Rough-looking flows with less distinct (more random) patterns on their surfaces may be flows that are more like terrestrial a'a flows, which are distinguished from pahoehoe flows by their higher viscosities and effusion rates. Near the center of the image there is an east-west trending, smooth-floored depression. The somewhat continuous width of this depression suggests that it is not simply formed by the edges of two

  19. Unsteady magnetohydrodynamic blood flow through irregular multi-stenosed arteries.

    Science.gov (United States)

    Mustapha, Norzieha; Amin, Norsarahaida; Chakravarty, Santabrata; Mandal, Prashanta Kumar

    2009-10-01

    Flow of an electrically conducting fluid characterizing blood through the arteries having irregular shaped multi-stenoses in the environment of a uniform transverse magnetic-field is analysed. The flow is considered to be axisymmetric with an outline of the irregular stenoses obtained from a three-dimensional casting of a mild stenosed artery, so that the physical problem becomes more realistic from the physiological point of view. The marker and cell (MAC) and successive-over-relaxation (SOR) methods are respectively used to solve the governing unsteady magnetohydrodynamic (MHD) equations and pressure-Poisson equation quantitatively and to observe the flow separation. The results obtained show that the flow separates mostly towards the downstream of the multi-stenoses. However, the flow separation region keeps on shrinking with the increasing intensity of the magnetic-field which completely disappears with sufficiently large value of the Hartmann number. The present observations certainly have some clinical implications relating to magnetotherapy which help reducing the complex flow separation zones causing flow disorder leading to the formation and progression of the arterial diseases.

  20. Unsteady magnetohydrodynamic blood flow through irregular multi-stenosed arteries.

    Science.gov (United States)

    Mustapha, Norzieha; Amin, Norsarahaida; Chakravarty, Santabrata; Mandal, Prashanta Kumar

    2009-10-01

    Flow of an electrically conducting fluid characterizing blood through the arteries having irregular shaped multi-stenoses in the environment of a uniform transverse magnetic-field is analysed. The flow is considered to be axisymmetric with an outline of the irregular stenoses obtained from a three-dimensional casting of a mild stenosed artery, so that the physical problem becomes more realistic from the physiological point of view. The marker and cell (MAC) and successive-over-relaxation (SOR) methods are respectively used to solve the governing unsteady magnetohydrodynamic (MHD) equations and pressure-Poisson equation quantitatively and to observe the flow separation. The results obtained show that the flow separates mostly towards the downstream of the multi-stenoses. However, the flow separation region keeps on shrinking with the increasing intensity of the magnetic-field which completely disappears with sufficiently large value of the Hartmann number. The present observations certainly have some clinical implications relating to magnetotherapy which help reducing the complex flow separation zones causing flow disorder leading to the formation and progression of the arterial diseases. PMID:19665698

  1. Online traffic flow model applying dynamic flow-density relation

    International Nuclear Information System (INIS)

    This dissertation describes a new approach of the online traffic flow modelling based on the hydrodynamic traffic flow model and an online process to adapt the flow-density relation dynamically. The new modelling approach was tested based on the real traffic situations in various homogeneous motorway sections and a motorway section with ramps and gave encouraging simulation results. This work is composed of two parts: first the analysis of traffic flow characteristics and second the development of a new online traffic flow model applying these characteristics. For homogeneous motorway sections traffic flow is classified into six different traffic states with different characteristics. Delimitation criteria were developed to separate these states. The hysteresis phenomena were analysed during the transitions between these traffic states. The traffic states and the transitions are represented on a states diagram with the flow axis and the density axis. For motorway sections with ramps the complicated traffic flow is simplified and classified into three traffic states depending on the propagation of congestion. The traffic states are represented on a phase diagram with the upstream demand axis and the interaction strength axis which was defined in this research. The states diagram and the phase diagram provide a basis for the development of the dynamic flow-density relation. The first-order hydrodynamic traffic flow model was programmed according to the cell-transmission scheme extended by the modification of flow dependent sending/receiving functions, the classification of cells and the determination strategy for the flow-density relation in the cells. The unreasonable results of macroscopic traffic flow models, which may occur in the first and last cells in certain conditions are alleviated by applying buffer cells between the traffic data and the model. The sending/receiving functions of the cells are determined dynamically based on the classification of the

  2. Tracking Per-Flow State – Binned Duration Flow Tracking

    Directory of Open Access Journals (Sweden)

    Brad Whitehead

    2012-01-01

    Full Text Available Recent advances in network monitoring have increasingly focused on obtaining per-flow information, such as flow state. Tracking the state of network flows opens up a new dimension of information gathering for network operators, allowing previously unattainable data to be captured. This paper presents a time efficient novel method – Binned Duration Flow Tracking (BDFT – of tracking per-flow state by grouping valid flows into “bins”. BDFT is intended for high-speed routers where CPU time is crucial. BDFT is time efficient by adopting Bloom filters as the primary data structures. Simulation results show that BDFT can achieve over 99% accuracy on traces of real network traffic.

  3. Arterial secondary blood flow patterns visualized with vector flow ultrasound

    DEFF Research Database (Denmark)

    Pedersen, Mads Møller; Pihl, Michael Johannes; Hansen, Jens Munk;

    2011-01-01

    This study presents the first quantification and visualisation of secondary flow patterns with vector flow ultrasound. The first commercial implementation of the vector flow method Transverse Oscillation was used to obtain in-vivo, 2D vector fields in real-time. The hypothesis of this study...... was that the rotational direction is constant within each artery. Three data sets of 10 seconds were obtained from three main arteries in healthy volunteers. For each data set the rotational flow patterns were identified during the diastole. Each data set contains a 2D vector field over time and with the vector angles...... and velocity magnitudes the blood flow patterns were visualised with streamlines in Matlab (Mathworks, Natick, MA, USA). The rotational flow was quantified by the angular frequency for each cardiac cycle, and the mean rotational frequencies and standard deviations were calculated for the abdominal aorta f-1...

  4. Hydrodynamic Instabilities in Rotating Fluids

    Institute of Scientific and Technical Information of China (English)

    KarlBuehler

    2000-01-01

    Rotating flow systems are often used to study stability phenomena and structure developments.The closed spherical gap prblem is generalized into an open flow system by superimposing a mass flux in meridional direction.The basic solutions at low Reynolds numbers are described by analytical methods.The nonlinear supercritical solutions are simulated numerically and realized in experiments.Novel steady and time-dependent modes of flows are obtained.The extensive results concern the stability behaviour.non-uniqueness of supercritical solutions,symmetry behaviour and transitions between steady and time-dependent solutions.The experimental investigations concern the visualization of the various instabilities and the quatitative description of the flow structures including the laminar-turbulent transition.A Comparison between theoretical and experimental results shows good agreement within the limit of rotational symmetric solutions from the theory.

  5. Flow rate limitation in open capillary channel flows.

    Science.gov (United States)

    Haake, Dennis; Rosendahl, Uwe; Ohlhoff, Antje; Dreyer, Michael E

    2006-09-01

    This paper reports the experimental and theoretical investigations of forced liquid flows through open capillary channels under reduced gravity conditions. An open capillary channel is a structure that establishes a liquid flow path at low Bond numbers, when the capillary pressure caused by the surface tension force dominates in comparison to the hydrostatic pressure induced by gravitational or residual accelerations. In case of steady flow through the channel, the capillary pressure of the free surface balances the pressure difference between the liquid and the surrounding constant-pressure gas phase. Because of convective and viscous momentum transport, the pressure along the flow path decreases and causes the free surface to bend inward. The maximum flow rate is achieved when the free surface collapses and gas ingestion occurs at the outlet. This critical flow rate depends on the geometry of the channel and the properties of the liquid. In this paper we present a comparison of the theoretical and experimental critical flow rates and surface profiles for convective dominated flows. For the prediction of the critical flow rate a one-dimensional theoretical model taking into account the entrance pressure loss and the frictional pressure loss in the channel is developed.

  6. In vitro heart valve testing: steady versus pulsatile flow.

    Science.gov (United States)

    Black, M M; Hose, D R; Lamb, C J; Lawford, P V; Ralph, S J

    1994-03-01

    The design of artificial heart valves has traditionally been based on the development of a prototype device which was then subjected to extensive laboratory testing in order to confirm its suitability for clinical use. In the past the in vitro assessment of a valve's performance was based principally on the measurement of parameters such as pressure difference, regurgitation and, more recently, energy losses. Such measurements can be defined as being at the 'macro' level and rarely show any clinically significant differences amongst currently available prostheses. The analytical approach to flow through heart valves has previously been hampered by difficulties experienced in solving the relevant equations of flow particularly in the case of pulsatile conditions. Computational techniques are now available which enable appropriate solutions to be obtained for these problems and consequently provide an opportunity for detailed examination of the 'micro' level of flow disturbances exhibited by the different valves. This present preliminary study is designed to illustrate the use of such an analytical approach to the flow through prosthetic valves. A single topic has been selected for this purpose which is the comparative value of steady versus pulsatile flow testing. A bileaflet valve was chosen for the analysis and a mathematical model of this valve in the aortic position of the Sheffield Pulse Duplicator was created. The theoretical analysis was carried out using a commercially available Computational Fluid Dynamics package, namely, FIDAP, on a SUN MICROSYSTEMS 10-30 workstation.(ABSTRACT TRUNCATED AT 250 WORDS)

  7. Measurement of tumor blood flow following neutron irradiation

    International Nuclear Information System (INIS)

    Clinical oncologists and cancer researchers benefit from information on the vascularization or non-vascularization of solid tumors because of blood flow's influence on three popular treatment types: hyperthermia therapy, radiotherapy, and chemotherapy. The objective of this research is the development of a clinically useful tumor blood flow measurements technique. The designed technique is sensitive, has good spatial resolution, in non-invasive and presents no risk to the patient beyond his usual treatment. Tumor blood flow was determined by measuring the washout of positron emitting isotopes created through neutron therapy treatment. In order to do this, several technical and scientific questions were addressed first. These questions have been answered through both theoretical calculation and measurement. The first question was answered through the measurement of macroscopic cross sections for the predominant nuclear reactions in the body. These results correlate well with an independent mathematical prediction of tissue activation and measurements of mouse spleen neutron activation. The second question was addressed by performing cell suspension and protein precipitation techniques on neutron activated mouse spleens. The third and final question was answered by using first physical principles to develop a model mimicking the blood flow system and measurement technique. In a final set of experiments, the above were applied to flow models and animals. The ultimate aim of this project is to apply its methodology to neutron therapy patients

  8. Participating in Clinical Trials

    Medline Plus

    Full Text Available ... In This Topic About Clinical Trials Risks and Benefits Terms to Know Finding a Clinical Trial Informed ... for more information Scientists usually do years of experiments in the laboratory and in animals before they even consider testing an experimental treatment ...

  9. Developing Clinical Competence

    NARCIS (Netherlands)

    P.F. Wimmers (Paul)

    2006-01-01

    textabstractThe development of clinical competence is the main purpose of medical education. The long road to become clinically competent starts on the first day of medical school, and every institution strives to select the best students. The responsibility of medical schools is to train th

  10. Clinical Supervision in Denmark

    DEFF Research Database (Denmark)

    Jacobsen, Claus Haugaard

    2011-01-01

    on giving and receiving clinical supervision as reported by therapists in Denmark. Method: Currently, the Danish sample consists of 350 clinical psychologist doing psychotherapy who completed DPCCQ. Data are currently being prepared for statistical analysis. Results: This paper will focus primarily...

  11. Participating in Clinical Trials

    Medline Plus

    Full Text Available ... In This Topic About Clinical Trials Risks and Benefits Terms to Know Finding a Clinical Trial Informed ... years of experiments in the laboratory and in animals before they even ... this early research occurs at universities and medical centers across the ...

  12. Molecular vibrational energy flow

    Science.gov (United States)

    Gruebele, M.; Bigwood, R.

    This article reviews some recent work in molecular vibrational energy flow (IVR), with emphasis on our own computational and experimental studies. We consider the problem in various representations, and use these to develop a family of simple models which combine specific molecular properties (e.g. size, vibrational frequencies) with statistical properties of the potential energy surface and wavefunctions. This marriage of molecular detail and statistical simplification captures trends of IVR mechanisms and survival probabilities beyond the abilities of purely statistical models or the computational limitations of full ab initio approaches. Of particular interest is IVR in the intermediate time regime, where heavy-atom skeletal modes take over the IVR process from hydrogenic motions even upon X H bond excitation. Experiments and calculations on prototype heavy-atom systems show that intermediate time IVR differs in many aspects from the early stages of hydrogenic mode IVR. As a result, IVR can be coherently frozen, with potential applications to selective chemistry.

  13. Waves and compressible flow

    CERN Document Server

    Ockendon, Hilary

    2016-01-01

    Now in its second edition, this book continues to give readers a broad mathematical basis for modelling and understanding the wide range of wave phenomena encountered in modern applications.  New and expanded material includes topics such as elastoplastic waves and waves in plasmas, as well as new exercises.  Comprehensive collections of models are used to illustrate the underpinning mathematical methodologies, which include the basic ideas of the relevant partial differential equations, characteristics, ray theory, asymptotic analysis, dispersion, shock waves, and weak solutions. Although the main focus is on compressible fluid flow, the authors show how intimately gasdynamic waves are related to wave phenomena in many other areas of physical science.   Special emphasis is placed on the development of physical intuition to supplement and reinforce analytical thinking. Each chapter includes a complete set of carefully prepared exercises, making this a suitable textbook for students in applied mathematics, ...

  14. Asynchronous Power Flow Controller

    Directory of Open Access Journals (Sweden)

    Rahul Juneja

    2014-04-01

    Full Text Available In the present system demand of electrical power increases so fast and transfer of electrical power is need of today‟s scenario. . The electrical power is transfer at same frequency through AC transmission line. However, power generation may be at different frequencies such as wind generation, sources at islanding or power generation in different countries. The proposed Asynchronous Power Flow Controller (APFC system essentially consists of two back-to-back voltage source converters as “Shunt Converter” and “Series Converter” which is coupled via a common dc link provided by a dc storage capacitor This paper suggests the power transfer and control between the sources operating at different or same frequencies.

  15. Active flows on trees

    CERN Document Server

    Forrow, Aden; Dunkel, Jörn

    2016-01-01

    Coherent, large scale dynamics in many nonequilibrium physical, biological, or information transport networks are driven by small-scale local energy input. We introduce and explore a generic model for compressible active flows on tree networks. In contrast to thermally-driven systems, active friction selects discrete states with only a small number of oscillation modes activated at distinct fixed amplitudes. This state selection interacts with graph topology to produce different localized dynamical time scales in separate regions of large networks. Using perturbation theory, we systematically predict the stationary states of noisy networks and find good agreement with a Bayesian state estimation based on a hidden Markov model applied to simulated time series data on binary trees. While the number of stable states per tree scales exponentially with the number of edges, the mean number of activated modes in each state averages $\\sim 1/4$ the number of edges. More broadly, these results suggest that the macrosco...

  16. Diffusion or bulk flow

    DEFF Research Database (Denmark)

    Schulz, Alexander

    2015-01-01

    the concentration gradient or bulk flow along a pressure gradient. The driving force seems to depend on the mode of phloem loading. In a majority of plant species phloem loading is a thermodynamically active process, involving the activity of membrane transporters in the sieve-element companion cell complex. Since...... assimilate movement includes an apoplasmic step, this mode is called apoplasmic loading. Well established is also the polymer-trap loading mode, where the phloem-transport sugars are raffinose-family oligomers in herbaceous plants. Also this mode depends on the investment of energy, here for sugar......Assimilates synthesized in the mesophyll of mature leaves move along the pre-phloem transport pathway to the bundle sheath of the minor veins from which they are loaded into the phloem. The present review discusses the most probable driving force(s) for the pre-phloem pathway, diffusion down...

  17. Flow Analysis: A Novel Approach For Classification.

    Science.gov (United States)

    Vakh, Christina; Falkova, Marina; Timofeeva, Irina; Moskvin, Alexey; Moskvin, Leonid; Bulatov, Andrey

    2016-09-01

    We suggest a novel approach for classification of flow analysis methods according to the conditions under which the mass transfer processes and chemical reactions take place in the flow mode: dispersion-convection flow methods and forced-convection flow methods. The first group includes continuous flow analysis, flow injection analysis, all injection analysis, sequential injection analysis, sequential injection chromatography, cross injection analysis, multi-commutated flow analysis, multi-syringe flow injection analysis, multi-pumping flow systems, loop flow analysis, and simultaneous injection effective mixing flow analysis. The second group includes segmented flow analysis, zone fluidics, flow batch analysis, sequential injection analysis with a mixing chamber, stepwise injection analysis, and multi-commutated stepwise injection analysis. The offered classification allows systematizing a large number of flow analysis methods. Recent developments and applications of dispersion-convection flow methods and forced-convection flow methods are presented.

  18. Regional cerebral blood flow in childhood headache

    International Nuclear Information System (INIS)

    Regional cerebral blood flow (rCBF) was measured in 16 cranial regions in 23 children and adolescents with frequent headaches using the non-invasive Xenon-133 inhalation technique. Blood flow response to 5% carbon dioxide (CO2) was also determined in 21 patients, while response to 50% oxygen was measured in the two patients with hemoglobinopathy. Included were 10 patients with a clinical diagnosis of migraine, 4 with musculoskeletal headaches, and 3 with features of both types. Also studied were 2 patients with primary thrombocythemia, 2 patients with hemoglobinopathy and headaches, 1 patient with polycythemia, and 1 with headaches following trauma. With two exceptions, rCBF determinations were done during an asymptomatic period. Baseline rCBF values tended to be higher in these young patients than in young adults done in our laboratory. Localized reduction in the expected blood flow surge after CO2 inhalation, most often noted posteriorly, was seen in 8 of the 13 vascular headaches, but in none of the musculoskeletal headache group. Both patients with primary thrombocythemia had normal baseline flow values and altered responsiveness to CO2 similar to that seen in migraineurs; thus, the frequently reported headache and transient neurologic signs with primary thrombocythemia are probably not due to microvascular obstruction as previously suggested. These data support the concept of pediatric migraine as a disorder of vasomotor function and also add to our knowledge of normal rCBF values in younger patients. Demonstration of altered vasomotor reactivity to CO2 could prove helpful in children whose headache is atypical

  19. Gait analysis: clinical facts.

    Science.gov (United States)

    Baker, Richard; Esquenazi, Alberto; Benedetti, Maria G; Desloovere, Kaat

    2016-08-01

    Gait analysis is a well-established tool for the quantitative assessment of gait disturbances providing functional diagnosis, assessment for treatment planning, and monitoring of disease progress. There is a large volume of literature on the research use of gait analysis, but evidence on its clinical routine use supports a favorable cost-benefit ratio in a limited number of conditions. Initially gait analysis was introduced to clinical practice to improve the management of children with cerebral palsy. However, there is good evidence to extend its use to patients with various upper motor neuron diseases, and to lower limb amputation. Thereby, the methodology for properly conducting and interpreting the exam is of paramount relevance. Appropriateness of gait analysis prescription and reliability of data obtained are required in the clinical environment. This paper provides an overview on guidelines for managing a clinical gait analysis service and on the principal clinical domains of its application: cerebral palsy, stroke, traumatic brain injury and lower limb amputation.

  20. Clinical Pathway for Thyroidectomy.

    Science.gov (United States)

    Villar del Moral, Jesús María; Soria Aledo, Víctor; Colina Alonso, Alberto; Flores Pastor, Benito; Gutiérrez Rodríguez, María Teresa; Ortega Serrano, Joaquín; Parra Hidalgo, Pedro; Ros López, Susana

    2015-05-01

    Clinical pathways are care plans applicable to patient care procedures that present variations in practice and a predictable clinical course. They are designed not as a substitute for clinical judgment, but rather as a means to improve the effectiveness and efficiency of the procedures. This clinical pathway is the result of a collaborative work of the Sections of Endocrine Surgery and Quality Management of the Spanish Association of Surgeons. It attempts to provide a framework for standardizing the performance of thyroidectomy, the most frequently performed operation in endocrine surgery. Along with the usual documents of clinical pathways (temporary matrix, variance tracking and information sheets, assessment indicators and a satisfaction questionnaire) it includes a review of the scientific evidence around different aspects of pre, intra and postoperative management. Among others, antibiotic and antithrombotic prophylaxis, preoperative preparation in hyperthyroidism, intraoperative neuromonitoring and systems for obtaining hemostasis are included, along with management of postoperative hypocalcemia.

  1. Situated clinical cognition.

    Science.gov (United States)

    Timpka, T

    1995-10-01

    The features characterizing study of clinical cognition in situ are formulated as: Re-cognition of context, culture, history and affect. Socializing and phenomenalistic elements are again included in the research agenda. Interest for representations: an analysis level is reserved for the symbols, rules and images relevant to define in models of clinical cognition. De-emphasis on computer modeling: investigations focus on the 'functional systems' in which computers are involved. Rootedness in classical philosophical problems: issues concerning situated clinical cognition are connected to the width of available theoretical literature. Belief in interdisciplinary studies: productive interactions between the new and traditional disciplines is anticipated, implying that new shared methods have to be developed. When scientific perspectives are broadened, a new balance has to be found between the relevance of the subject of study and methodological rigor. The situated clinical cognition framework is to allow for moving between models, theories, and perspectives, as it does not presuppose a singular model of clinical thinking.

  2. Clinical PET application

    Energy Technology Data Exchange (ETDEWEB)

    Lim, Sang-Moo; Hong, S. W.; Choi, C. W.; Yang, S. D.; Choi, J. S.; Kweon, O. J. et al. [Korea Cancer Center Hospital, Seoul (Korea)

    2000-12-01

    PET gives various metabolic images, and is very important, new diagnostic modality in clinical oncology. In Korea Cancer Center Hospital, PET is installed as a research tool of long-mid-term atomic research project. For the efficient use of PET for clinical and research projects, income from the patients should be managed to get the raw material, equipment, manpower, and also for the clinical PET research. 1. Support the clinical application of PET in oncology. 2. Budgetary management of income, costs for raw material, equipment, manpower, and the clinical PET research project. In this year, 1,327 cases of PET images were obtained, which resulted total income of 829,770,000won. Increased demand for {sup 18}FDG in and outside KCCH need more than 2 times production of {sup 18} in a day. Manpower should be added for the second PET operation and RI production. 10 figs., 4 tabs. (Author)

  3. The blood flow changes associated with idiopathic and secondary intracranial hypertension

    International Nuclear Information System (INIS)

    Full text: The radiological diagnosis of idiopathic intracranial hypertension (IIH) is one of exclusion and as the MR venogram is prone to flow artefacts, the diagnosis of secondary intracranial hypertension (SIH) can also be problematic. The purpose of this paper is to define the blood flow characteristics, which are useful in the diagnosis of these conditions. Twelve patients with clinical findings suggestive of IIH and 12 control subjects were investigated with MR venography and MR flow quantification studies of the cerebral arteries and veins. Total cerebral blood flow, superior sagittal sinus (SSS) and straight sinus (ST) blood flows were measured. MR venography confirmed 7 of the 12 patients had venous outflow obstruction and thus SIH. The remaining 5 patients had IIH. The control patients mean total blood flow was 855 ml/min, the SSS flow was 400ml/min and the ST flow 117 ml/min. The total blood flow in the IIH patients was 46% higher (P = 0.0002) and the ST blood flow 38% higher (P = 0.05) than the control group, the SSS flow was 17% higher but this failed to reach significance. In SIH the SSS flow was reduced by 25% (P = 0.003) compared with the control group, the total and ST blood flow were not significantly altered. In IIH there is hyperaemia and the SSS appears limited in its ability to increase flow, therefore venous collaterals carry a greater load. In SIH, selective obstruction of the SSS reduces flow in this vessel but total blood flow is normal indicating there is also increased flow in collateral veins. Presumably the limited ability of the SSS to drain blood away from the brain in each condition raises venous sinus pressure and alters CSF resorption giving raised CSF pressure. Copyright (2002) Blackwell Science Pty Ltd

  4. Regional cerebral blood flow in neuropediatrics

    International Nuclear Information System (INIS)

    Single photon emission computed tomography can effectively and non-invasively measure regional blood flow. Mostly used 99mTc-HMPAO is a safe brain imaging agent for pediatric applications. The radiation dose is acceptable. Knowledge of the normal rCBF pattern, including normal asymmetries and variations due to age, is necessary prerequisite for the evaluation and reporting of the results of 99mTc-HMPAO brain SPECT studies in clinical practice. The interpretation of he rCBF study in a child requires knowledge of normal brain maturation. The aim of the present review is to focus on the contribution to clinical developmental neurology of SPECT The clinical use of SPECT in developmental neurology are epilepsy, brain death, acute neurological loss including stroke, language disorders, cerebral palsy, high-risk neonates, hypertension due to renovascular disease, traumatic brain injury, migraine, anorexia nervosa, autism, Gilles de la Tourette syndrome, attention deficit disorder-hyperactivity, and monitoring therapy. Sedation is not routinely used, rather each child is evaluated. However, drug sedation is mandatory in some uncooperative children. (author)

  5. Magnetic heat pump flow director

    Science.gov (United States)

    Howard, Frank S. (Inventor)

    1995-01-01

    A fluid flow director is disclosed. The director comprises a handle body and combed-teeth extending from one side of the body. The body can be formed of a clear plastic such as acrylic. The director can be used with heat exchangers such as a magnetic heat pump and can minimize the undesired mixing of fluid flows. The types of heat exchangers can encompass both heat pumps and refrigerators. The director can adjust the fluid flow of liquid or gas along desired flow directions. A method of applying the flow director within a magnetic heat pump application is also disclosed where the comb-teeth portions of the director are inserted into the fluid flow paths of the heat pump.

  6. The AdaBoost Flow

    CERN Document Server

    Lykov, A; Vaninsky, K

    2011-01-01

    We introduce a dynamical system which we call the AdaBoost flow. The flow is defined by a system of ODEs with control. We show how by a suitable choice of control AdaBoost algorithm of Schapire and Freund and arc-gv algorithm of Breiman can be embedded in the AdaBoost flow. We also show how previously studied by Schapire and Singer confidence rated prediction can be obtained from our continuous time approach. We introduce a new continuous time algorithm which we call superBoost and describe its properties. The AdaBoost flow equations coincide with the equations of dynamics of the nonperiodic Toda system written in terms of spectral variables. This establishes a connection between two seemingly unrelated fields of boosting algorithms and classical integrable models. Finally we explain similarity of the AdaBoost flow with Perelman's ideas to control Ricci flow.

  7. Lava crusts and flow dynamics

    Science.gov (United States)

    Kilburn, C. R. J.

    1993-01-01

    Lava flows can be considered as hot viscous cores within thinner, solidified crusts. Interaction between crust and core determines a flow's morphological and dynamical evolution. When the lava core dominates, flow advance approaches a steady state. When crusts are the limiting factor, advance is more irregular. These two conditions can be distinguished by a timescale ratio comparing rates of core deformation and crustal formation. Aa and budding pahoehoe lavas are used as examples of core- and crustal-dominated flows, respectively. A simple model describes the transition between pahoehoe and aa flow in terms of lava discharge rate, underlying slope, and either the thickness or velocity of the flow front. The model shows that aa morphologies are characterized by higher discharge rates and frontal velocities and yields good quantitative agreement with empirical relations distinguishing pahoehoe and aa emplacement on Hawaii.

  8. NUMERICAL SIMULATIONS OF CAVITATING FLOWS

    Institute of Scientific and Technical Information of China (English)

    Wu Lei

    2003-01-01

    A new model, which involves viscous and multi-phase effects, was given to study cavitating flows. A local compressible model was established by introducing a density-pressure function to account for the two-phase flow of water/vapor and the transition from one phase to the other. An algorithm for calculating variable-density N-S equations of cavitating flow problem was put forward. The present method yields reasonable results for both steady and unsteady cavitating flows in 2D and 3D cases. The numerical results of unsteady character of cavitating flows around hydrofoils coincide well with experimental data. It indicates the feasibility to apply this method to a variety of cavitating flows of practical problems.

  9. Methods for measurement of cerebral blood flow in man

    DEFF Research Database (Denmark)

    Lassen, N A

    1976-01-01

    A survey of the currently available methods for the measurement of cerebral blood flow in man is given. Many of the clinically important brain diseases such as tumors, stroke, brain trauma or epilepsy entail focal or regional flow alterations. Therefore a special emphasis is placed on methods...... information both on spatial localization and, especially, on ischemic areas. The most promising is computer-assisted axial tomography with freely diffusible radioactive isotopes or with x-rays using an intra-arterial injection of contrast. But, the available techniques are still too slow: in order to measure...

  10. Perfusion pressure flow study in the upper urinary tract

    Directory of Open Access Journals (Sweden)

    Hong-Lin Cheng

    2015-06-01

    Full Text Available Hydronephrosis with an undetermined pathology is a common condition detected in imaging studies. In urological clinical practice, it is a persistent dilemma to predict whether this condition will progress to result in the deterioration of renal function. Perfusion pressure flow study of the upper urinary tract, known as the Whitaker test, provides an alternative diagnostic tool for solving this condition. Perfusion pressure flow study has been criticized for its invasiveness, nonphysiological approach, and inconsistency in predicting outcomes. However, it continues to be used to evaluate difficult or equivocal cases and to provide an objective assessment of the upper urinary tract.

  11. SPECT Myocardial Blood Flow Quantitation Concludes Equivocal Myocardial Perfusion SPECT Studies to Increase Diagnostic Benefits.

    Science.gov (United States)

    Chen, Lung-Ching; Lin, Chih-Yuan; Chen, Ing-Jou; Ku, Chi-Tai; Chen, Yen-Kung; Hsu, Bailing

    2016-01-01

    Recently, myocardial blood flow quantitation with dynamic SPECT/CT has been reported to enhance the detection of coronary artery disease in human. This advance has created important clinical applications to coronary artery disease diagnosis and management for areas where myocardial perfusion PET tracers are not available. We present 2 clinical cases that undergone a combined test of 1-day rest/dipyridamole-stress dynamic SPECT and ECG-gated myocardial perfusion SPECT scans using an integrated imaging protocol and demonstrate that flow parameters are capable to conclude equivocal myocardial perfusion SPECT studies, therefore increasing diagnostic benefits to add value in making clinical decisions.

  12. SPECT Myocardial Blood Flow Quantitation Concludes Equivocal Myocardial Perfusion SPECT Studies to Increase Diagnostic Benefits.

    Science.gov (United States)

    Chen, Lung-Ching; Lin, Chih-Yuan; Chen, Ing-Jou; Ku, Chi-Tai; Chen, Yen-Kung; Hsu, Bailing

    2016-01-01

    Recently, myocardial blood flow quantitation with dynamic SPECT/CT has been reported to enhance the detection of coronary artery disease in human. This advance has created important clinical applications to coronary artery disease diagnosis and management for areas where myocardial perfusion PET tracers are not available. We present 2 clinical cases that undergone a combined test of 1-day rest/dipyridamole-stress dynamic SPECT and ECG-gated myocardial perfusion SPECT scans using an integrated imaging protocol and demonstrate that flow parameters are capable to conclude equivocal myocardial perfusion SPECT studies, therefore increasing diagnostic benefits to add value in making clinical decisions. PMID:26053731

  13. Multiparametric flow cytometry profiling of neoplastic plasma cells in multiple myeloma

    DEFF Research Database (Denmark)

    Johnsen, Hans E; Bøgsted, Martin; Klausen, Tobias W;

    2010-01-01

    The clinical impact of multiparametric flow cytometry (MFC) in multiple myeloma (MM) is still unclear and under evaluation. Further progress relies on multiparametric profiling of the neoplastic plasma cell (PC) compartment to provide an accurate image of the stage of differentiation. The primary......, and predictive information useful in clinical practice, which will be prospectively validated within the European Myeloma Network (EMN). © 2010 International Clinical Cytometry Society....

  14. Clinical Research Methodology 2: Observational Clinical Research.

    Science.gov (United States)

    Sessler, Daniel I; Imrey, Peter B

    2015-10-01

    Case-control and cohort studies are invaluable research tools and provide the strongest feasible research designs for addressing some questions. Case-control studies usually involve retrospective data collection. Cohort studies can involve retrospective, ambidirectional, or prospective data collection. Observational studies are subject to errors attributable to selection bias, confounding, measurement bias, and reverse causation-in addition to errors of chance. Confounding can be statistically controlled to the extent that potential factors are known and accurately measured, but, in practice, bias and unknown confounders usually remain additional potential sources of error, often of unknown magnitude and clinical impact. Causality-the most clinically useful relation between exposure and outcome-can rarely be definitively determined from observational studies because intentional, controlled manipulations of exposures are not involved. In this article, we review several types of observational clinical research: case series, comparative case-control and cohort studies, and hybrid designs in which case-control analyses are performed on selected members of cohorts. We also discuss the analytic issues that arise when groups to be compared in an observational study, such as patients receiving different therapies, are not comparable in other respects.

  15. A Marine Traffic Flow Model

    OpenAIRE

    Tsz Leung Yip

    2013-01-01

    A model is developed for studying marine traffic flow through classical traffic flow theories, which can provide us with a better understanding of the phenomenon of traffic flow of ships. On one hand, marine traffic has its special features and is fundamentally different from highway, air and pedestrian traffic. The existing traffic models cannot be simply extended to marine traffic without addressing marine traffic features. On the other hand, existing literature on marine traffic focuses on...

  16. Subchannel analysis with flow blockages

    Science.gov (United States)

    Sabotinov, L.

    1985-05-01

    The steady state single-phase three-dimensional flow in the rod bundle geometry of a nuclear pressurized water reactor was calculated with the PHOENICS 84 program. Flow blockages, which may occur under accident conditions, are simulated. Results show that PHOENICS-84 can be applied to calculation of the three-dimensional fields of velocities in fuel rod bundles containing complete flow blockages in cells. The code can treat recirculation zones.

  17. Elliptic Flow at Large Viscosity

    OpenAIRE

    Koch, Volker

    2009-01-01

    In this contribution we present an alternative scenario for the large elliptic flow observed in relativistic heavy ion collisions. Motivated by recent results from Lattice QCD on flavor off-diagonal susceptibilities we argue that the matter right above $T_{c}$ can be described by single-particle dynamics in a repulsive single-particle potential, which in turn gives rise to elliptic flow. These ideas can be tested experimentally by measuring elliptic flow of heavy quarks, preferably via the me...

  18. Coincident Indicators of Capital Flows

    OpenAIRE

    Malika Pant; Yanliang Miao

    2012-01-01

    Capital flows data from Balance of Payments statistics often lag 3-6 months, which renders timely surveillance and policy deliberation difficult. To address the tension, we propose two coincident composite indicators for capital flows that improve upon existing proxies. We find that the most widely used proxy, the capital tracker, often overpredicts net flows by 30 percent. We augment the tracker into a composite indicator by assigning to it a lesser but optimally estimated weight while incor...

  19. Image-based assessment of fractional flow reserve.

    Science.gov (United States)

    Tu, Shengxian; Bourantas, Christos V; Nørgaard, Bjarne L; Kassab, Ghassan S; Koo, Bon-Kwon; Reiber, Johan H C

    2015-01-01

    Pressure-derived fractional flow reserve (FFR) is an index of the haemodynamic significance of a coronary lesion. Numerous studies have provided robust evidence that FFR-guided percutaneous coronary intervention is associated with better clinical outcomes and reduces the need for repeat revascularisation. Although FFR is regarded as the gold standard for assessing lesion severity, it has limited clinical applications, mainly because it is a relatively expensive and time-consuming procedure. To overcome these limitations, several computational-based methodologies have been developed which enable estimation of the FFR in three-dimensional models derived from anatomic imaging data. Multislice computed tomographic coronary angiography and quantitative coronary angiography have been proposed for coronary reconstruction and computational evaluation of the FFR. In this review article, we describe the currently available methodologies for the computational estimation of FFR, present evidence derived from their clinical evaluations, stress their limitations, and discuss their potential value in clinical practice.

  20. Optic flow and autonomous navigation.

    Science.gov (United States)

    Campani, M; Giachetti, A; Torre, V

    1995-01-01

    Many animals, especially insects, compute and use optic flow to control their motion direction and to avoid obstacles. Recent advances in computer vision have shown that an adequate optic flow can be computed from image sequences. Therefore studying whether artificial systems, such as robots, can use optic flow for similar purposes is of particular interest. Experiments are reviewed that suggest the possible use of optic flow for the navigation of a robot moving in indoor and outdoor environments. The optic flow is used to detect and localise obstacles in indoor scenes, such as corridors, offices, and laboratories. These routines are based on the computation of a reduced optic flow. The robot is usually able to avoid large obstacles such as a chair or a person. The avoidance performances of the proposed algorithm critically depend on the optomotor reaction of the robot. The optic flow can be used to understand the ego-motion in outdoor scenes, that is, to obtain information on the absolute velocity of the moving vehicle and to detect the presence of other moving objects. A critical step is the correction of the optic flow for shocks and vibrations present during image acquisition. The results obtained suggest that optic flow can be successfully used by biological and artificial systems to control their navigation. Moreover, both systems require fast and accurate optomotor reactions and need to compensate for the instability of the viewed world. PMID:7617428

  1. Flow measurement by ultrasonic method

    International Nuclear Information System (INIS)

    An Ultrasonic Flow Meter (USFM) wasdeveloped to measure flow velocity of high temperature fluid in a pipe. To protect ultrasonic transducers from high temperature, guide rods were used. From the study on mechanical structure and acoustic property, the guide rod and the electronic circuit were improved to have capabilities of temperature compensation, quick response, high accuracy and not to be easily disturbed by bubbles contained in the fluid flow. Using a water flow loop, the test results proved the accuracy of +-1.0 percent and response time of 10 m sec

  2. UZ Flow Models and Submodels

    Energy Technology Data Exchange (ETDEWEB)

    P. Dixon

    2004-02-11

    The purpose of this Model Report is to document the unsaturated zone (UZ) fluid flow and tracer transport models and submodels as well as the flow fields generated utilizing the UZ Flow and Transport Model of Yucca Mountain (UZ Model), Nevada. This work was planned in ''Technical Work Plan (TWP) for: Performance Assessment Unsaturated Zone'' (BSC 2002 [160819], Section 1.10, Work Package AUZM06). The UZ Model has revised, updated, and enhanced the previous UZ Flow Model REV 00 ICN 01 (BSC 2001 [158726]) by incorporation of the conceptual repository design with new grids, recalibration of property sets, and more comprehensive validation effort. The flow fields describe fracture-fracture, matrix-matrix, and fracture-matrix liquid flow rates and their spatial distributions as well as moisture conditions in the UZ system. These 3-D UZ flow fields are used directly by Performance Assessment (PA). The model and submodels evaluate important hydrogeologic processes in the UZ as well as geochemistry and geothermal conditions. These provide the necessary framework to test conceptual hypotheses of flow and transport at different scales and predict flow and transport behavior under a variety of climatic conditions. In addition, this Model Report supports several PA activities, including abstractions, particle-tracking transport simulations, and the UZ Radionuclide Transport Model.

  3. Fundamentals of gas particle flow

    CERN Document Server

    Rudinger, G

    1980-01-01

    Fundamentals of Gas-Particle Flow is an edited, updated, and expanded version of a number of lectures presented on the "Gas-Solid Suspensions” course organized by the von Karman Institute for Fluid Dynamics. Materials presented in this book are mostly analytical in nature, but some experimental techniques are included. The book focuses on relaxation processes, including the viscous drag of single particles, drag in gas-particles flow, gas-particle heat transfer, equilibrium, and frozen flow. It also discusses the dynamics of single particles, such as particles in an arbitrary flow, in a r

  4. Precipitated silica as flow regulator.

    Science.gov (United States)

    Müller, Anne-Kathrin; Ruppel, Joanna; Drexel, Claus-Peter; Zimmermann, Ingfried

    2008-08-01

    Flow regulators are added to solid pharmaceutical formulations to improve the flow properties of the powder mixtures. The primary particles of the flow regulators exist in the form of huge agglomerates which are broken down into smaller aggregates during the blending process. These smaller aggregates adsorb at the surface of the solid's grains and thus diminish attractive Van-der-Waals-forces by increasing the roughness of the host's surface. In most cases amorphous silica is used as flow additive but material properties like particle size or bond strength influence the desagglomeration tendency of the agglomerates and thus the flow regulating potency of each silica. For some silica types we will show that the differences in their flow regulating potency are due to the rate and extent by which they are able to cover the surface of the host particles. Binary powder mixtures consisting of a pharmaceutical excipient and an added flow regulator were blended in a Turbula mixer for a defined period of time. As pharmaceutical excipient corn starch was used. The flow regulators were represented by a selection of amorphous silicon dioxide types like a commercial fumed silica and various types of SIPERNAT precipitated silica provided by Evonik-Degussa GmbH, Hanau, Germany. Flowability parameters of the mixtures were characterized by means of a tensile strength tester. The reduction of tensile strength with the blending time can be correlated with an increase in fragmentation of the flow regulator. PMID:18595668

  5. Optic flow and autonomous navigation.

    Science.gov (United States)

    Campani, M; Giachetti, A; Torre, V

    1995-01-01

    Many animals, especially insects, compute and use optic flow to control their motion direction and to avoid obstacles. Recent advances in computer vision have shown that an adequate optic flow can be computed from image sequences. Therefore studying whether artificial systems, such as robots, can use optic flow for similar purposes is of particular interest. Experiments are reviewed that suggest the possible use of optic flow for the navigation of a robot moving in indoor and outdoor environments. The optic flow is used to detect and localise obstacles in indoor scenes, such as corridors, offices, and laboratories. These routines are based on the computation of a reduced optic flow. The robot is usually able to avoid large obstacles such as a chair or a person. The avoidance performances of the proposed algorithm critically depend on the optomotor reaction of the robot. The optic flow can be used to understand the ego-motion in outdoor scenes, that is, to obtain information on the absolute velocity of the moving vehicle and to detect the presence of other moving objects. A critical step is the correction of the optic flow for shocks and vibrations present during image acquisition. The results obtained suggest that optic flow can be successfully used by biological and artificial systems to control their navigation. Moreover, both systems require fast and accurate optomotor reactions and need to compensate for the instability of the viewed world.

  6. Module bay with directed flow

    Science.gov (United States)

    Torczynski, John R.

    2001-02-27

    A module bay requires less cleanroom airflow. A shaped gas inlet passage can allow cleanroom air into the module bay with flow velocity preferentially directed toward contaminant rich portions of a processing module in the module bay. Preferential gas flow direction can more efficiently purge contaminants from appropriate portions of the module bay, allowing a reduced cleanroom air flow rate for contaminant removal. A shelf extending from an air inlet slit in one wall of a module bay can direct air flowing therethrough toward contaminant-rich portions of the module bay, such as a junction between a lid and base of a processing module.

  7. FLOW PROPERTIES OF COHESIVE NANOPOWDERS

    Institute of Scientific and Technical Information of China (English)

    Jürgen Tomas

    2003-01-01

    The fundamentals of cohesive powder consolidation and flow behaviour using a reasonable combination of particle and continuum mechanics are explained. By means of the model "stiff particles with soft contacts", the influence of elastic-plastic repulsion in particle contacts is demonstrated. With this as the physical basis, the stationary yield locus, instantaneous yield loci and consolidation loci, flow function and compression function are presented. The flow properties of a very cohesive titania nanopowder (ds=200 nm) are shown. These models ara used to evaluate shear cell test results as constitutive functions for computer aided apparatus design for reliable powder flow.

  8. Flow Deflection in Intersected Tubes

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    In order to verify the flow interference at the fracture intersections, a group of hydraulic simulations of crossing flow was carried out. The manifold interference effects at the intersection of fractures on water flow has been confirmed extensively either in the normal or in the oblique intersected tubes as well as in the intersected tubes of either equal or variant diameters. Consequently, suggest that the fissure network can no longer be taken as a set of solitary fractures, but as a set of elementary intersected ractures. The deflection effect at fracture intersections on the water flow should be taken into considwhen is dealt with any theory related to the water migration in fractures.

  9. Ferrofluid flow for TOUGH2

    Energy Technology Data Exchange (ETDEWEB)

    Oldenburg, Curtis; Moridis, George

    1998-03-24

    We have developed EOS7M, a ferrofluid flow and transport module for TOUGH2. EOS7M calculates the magnetic forces on ferrofluid caused by an external magnetic field and allows simulation of flow and advective transport of ferrofluid-water mixtures through porous media. Such flow problems are strongly coupled and well suited to the TOUGH2 framework. Preliminary applications of EOS7M to some simple pressure and flow problems for which experiments were carried out in the lab show good qualitative agreement with the laboratory results.

  10. Clinical PET application

    Energy Technology Data Exchange (ETDEWEB)

    Lim, Sang Moo; Hong, Song W.; Choi, Chang W.; Yang, Seong Dae [Korea Cancer Center Hospital, Seoul (Korea)

    1997-12-01

    PET gives various methabolic images, and is very important, new diagnostic modality in clinical oncology. In Korea Cancer Center Hospital, PET is installed as a research tool of long-mid-term atomic research project. For the efficient use of PET for clinical and research projects, income from the patients should be managed to get the raw material, equipment, manpower, and also for the clinical PET research. 1. Support the clinical application of PET in oncology. 2. Budgetary management of income, costs for raw material, equipment, manpower, and the clinical PET research project. In this year, 250 cases of PET images were obtained, which resulted total income of 180,000,000 won. 50,000,000 won was deposited for the 1998 PET clinical research. Second year PET clinical research should be managed under unified project. Increased demand for {sup 18}FDG in and outside KCCH need more than 2 times production of {sup 18}FDG in a day purchase of HPLC pump and {sup 68}Ga pin source which was delayed due to economic crisis, should be done early in 1998. (author). 2 figs., 3 tabs.

  11. Clinical microbiology informatics.

    Science.gov (United States)

    Rhoads, Daniel D; Sintchenko, Vitali; Rauch, Carol A; Pantanowitz, Liron

    2014-10-01

    The clinical microbiology laboratory has responsibilities ranging from characterizing the causative agent in a patient's infection to helping detect global disease outbreaks. All of these processes are increasingly becoming partnered more intimately with informatics. Effective application of informatics tools can increase the accuracy, timeliness, and completeness of microbiology testing while decreasing the laboratory workload, which can lead to optimized laboratory workflow and decreased costs. Informatics is poised to be increasingly relevant in clinical microbiology, with the advent of total laboratory automation, complex instrument interfaces, electronic health records, clinical decision support tools, and the clinical implementation of microbial genome sequencing. This review discusses the diverse informatics aspects that are relevant to the clinical microbiology laboratory, including the following: the microbiology laboratory information system, decision support tools, expert systems, instrument interfaces, total laboratory automation, telemicrobiology, automated image analysis, nucleic acid sequence databases, electronic reporting of infectious agents to public health agencies, and disease outbreak surveillance. The breadth and utility of informatics tools used in clinical microbiology have made them indispensable to contemporary clinical and laboratory practice. Continued advances in technology and development of these informatics tools will further improve patient and public health care in the future.

  12. Coriolis mass flow rate meters for low flows

    NARCIS (Netherlands)

    Mehendale, Aditya

    2008-01-01

    The accurate and quick measurement of small mass flow rates (~10 mg/s) of fluids is considered an "enabling technology" in semiconductor, fine-chemical, and food & drugs industries. Flowmeters based on the Coriolis effect offer the most direct sensing of the mass flow rate, and for this reason do no

  13. Frictional flow characteristics of microconvective flow for variable fluid properties

    Science.gov (United States)

    Kumar, Rajan; Mahulikar, Shripad P.

    2015-12-01

    The present work investigates the frictional flow characteristics of water flowing through a circular microchannel with variable fluid properties. The computational analysis reveals the importance of physical mechanisms due to variations in thermophysical fluid properties such as viscosity μ(T), thermal conductivity k(T) and density ρ(T) and also their contribution in the characteristics of frictional flow. Various combinations of thermophysical fluid properties have been used to find their effects on fluid friction. It is observed that the fluid friction attains the maximum value in the vicinity of the inlet and diminishes along the flow. The main reasons are attributed to this, (1) near the inlet, there is a flow undevelopment (the reverse process of flow development) due to μ(T) variation. (2) The viscosity of the water decreases with increasing temperature, which reduces fluid friction along the flow. It is noted that the skin friction coefficient (cf) reduces with increasing fluid mean velocity for a same value of constant wall heat flux ({q}{{w}}\\prime\\prime ). In the vicinity of the inlet, the deviation of Poiseuille number (Po) from 64 (constant properties solution) is also investigated in this paper. Additionally, the relationship between Reynolds number (Re) and cf, Po and Re have been proposed for different combinations of thermophysical fluid properties. This investigation also shows that the effect of fluid property variations on pressure drop is highly significant for microconvective water flow.

  14. Feasibility study of laminar flow bodies in fully turbulent flow

    International Nuclear Information System (INIS)

    One of the most important design requirements of long range autonomous underwater vehicles (AUVs) is to minimize propulsive power. An important and relatively easy way of achieving this is by careful selection of hull shape. Two main schools of thought in this respect are: if laminar flow can be maintained for a long length of the body, the effective drag can be reduced; it is not possible to maintain laminar flow for a significant length of the body and hull design should be based on turbulent flow conditions. In this paper, a feasibility study of laminar flow designs is undertaken under the assumption that flow will be turbulent over the entire length. For comparison two laminar flow designs X-35 and F-57 are selected and results are compared with those of two typical torpedo shaped bodies, namely AFTERBODY1 and AFTERBODY2 of DTNSRDC. It has been shown that laminar flow bodies have 10--15% higher drag when flow is turbulent over the entire length. Hence there is some hydrodynamic risk involved in adopting such laminar bodies without further consideration

  15. Optimal Power Flow Pursuit

    Energy Technology Data Exchange (ETDEWEB)

    Dall' Anese, Emiliano

    2016-08-01

    Past works that focused on addressing power-quality and reliability concerns related to renewable energy resources (RESs) operating with business-as-usual practices have looked at the design of Volt/VAr and Volt/Watt strategies to regulate real or reactive powers based on local voltage measurements, so that terminal voltages are within acceptable levels. These control strategies have the potential of operating at the same time scale of distribution-system dynamics, and can therefore mitigate disturbances precipitated fast time-varying loads and ambient conditions; however, they do not necessarily guarantee system-level optimality, and stability claims are mainly based on empirical evidences. On a different time scale, centralized and distributed optimal power flow (OPF) algorithms have been proposed to compute optimal steady-state inverter setpoints, so that power losses and voltage deviations are minimized and economic benefits to end-users providing ancillary services are maximized. However, traditional OPF schemes may offer decision making capabilities that do not match the dynamics of distribution systems. Particularly, during the time required to collect data from all the nodes of the network (e.g., loads), solve the OPF, and subsequently dispatch setpoints, the underlying load, ambient, and network conditions may have already changed; in this case, the DER output powers would be consistently regulated around outdated setpoints, leading to suboptimal system operation and violation of relevant electrical limits. The present work focuses on the synthesis of distributed RES-inverter controllers that leverage the opportunities for fast feedback offered by power-electronics interfaced RESs. The overarching objective is to bridge the temporal gap between long-term system optimization and real-time control, to enable seamless RES integration in large scale with stability and efficiency guarantees, while congruently pursuing system-level optimization objectives. The

  16. Uranyl Nitrate Flow Loop

    Energy Technology Data Exchange (ETDEWEB)

    Ladd-Lively, Jennifer L [ORNL

    2008-10-01

    The objectives of the work discussed in this report were to: (1) develop a flow loop that would simulate the purified uranium-bearing aqueous stream exiting the solvent extraction process in a natural uranium conversion plant (NUCP); (2) develop a test plan that would simulate normal operation and disturbances that could be anticipated in an NUCP; (3) use the flow loop to test commercially available flowmeters for use as safeguards monitors; and (4) recommend a flowmeter for production-scale testing at an NUCP. There has been interest in safeguarding conversion plants because the intermediate products [uranium dioxide (UO{sub 2}), uranium tetrafluoride (UF{sub 4}), and uranium hexafluoride (UF{sub 6})] are all suitable uranium feedstocks for producing special nuclear materials. Furthermore, if safeguards are not applied virtually any nuclear weapons program can obtain these feedstocks without detection by the International Atomic Energy Agency (IAEA). Historically, IAEA had not implemented safeguards until the purified UF{sub 6} product was declared as feedstock for enrichment plants. H. A. Elayat et al. provide a basic definition of a safeguards system: 'The function of a safeguards system on a chemical conversion plant is in general terms to verify that no useful nuclear material is being diverted to use in a nuclear weapons program'. The IAEA now considers all highly purified uranium compounds as candidates for safeguarding. DOE is currently interested in 'developing instruments, tools, strategies, and methods that could be of use to the IAEA in the application of safeguards' for materials found in the front end of the nuclear fuel cycle-prior to the production of the uranium hexafluoride or oxides that have been the traditional starting point for IAEA safeguards. Several national laboratories, including Oak Ridge, Los Alamos, Lawrence Livermore, and Brookhaven, have been involved in developing tools or techniques for safeguarding conversion

  17. Marking out the clinical expert/clinical leader/clinical scholar: perspectives from nurses in the clinical arena

    OpenAIRE

    Mannix, Judy; Wilkes, Lesley; Jackson, Debra

    2013-01-01

    Background Clinical scholarship has been conceptualised and theorised in the nursing literature for over 30 years but no research has captured nurses’ clinicians’ views on how it differs or is the same as clinical expertise and clinical leadership. The aim of this study was to determine clinical nurses’ understanding of the differences and similarities between the clinical expert, clinical leader and clinical scholar. Methods A descriptive interpretative qualitative approach using semi-struct...

  18. Mindfulness and clinical psychology.

    Science.gov (United States)

    Childs, David

    2011-09-01

    Does mindfulness offer more to psychology than a useful therapeutic technique? This paper argues that it can also establish a state of presence which is understood in relation to the practice of phenomenology. Mindfulness is then both linked to a Western intellectual tradition and offers that tradition a systematic method. This is an opening for psychological investigation of the non-conceptual basis of everyday experience. The combination of this theoretical stance with the increasingly widespread practical training of clinical psychologists in mindfulness has broad implications for clinical practice; this is illustrated in relation to the descriptive approach to clinical problems, qualitative research, and reflective practice.

  19. [Midwifery clinical practicum education].

    Science.gov (United States)

    Kao, Chien-Huei; Gau, Meei-Ling

    2013-06-01

    Midwifery is a practical facet of the health sciences that emphasizes professional competence-oriented teaching and learning. Cognitive and practical processes integrate and build midwifery student professional knowledge, attitudes, and skills. Clinical education is a teaching method and strategy used to prepare midwifery students for professional practice. Midwifery clinical teaching plans are designed using literature review, expert opinions, and student comments and determine total required hours and caseloads. Midwifery clinical teaching activities and methods promote self-reflection, childbirth education fundamentals, learning by role model observation, and learning role function through overseas observership programs. This paper discusses midwifery education dilemmas and coping methods in Taiwan.

  20. CME ON CLINICAL RESEARCH

    Directory of Open Access Journals (Sweden)

    Suneel. I. Majagi

    2012-06-01

    Full Text Available Safety and efficacy are the two major concerns for any drug therapy. Globally clinical research plays an inevitable role in bringing a new molecule into the market after its synthesis by the pharmaceutical industries. Availability of large patient population, highly educated and skilled manpower, wide spectrum of diseases and favorable economic environment imply India’s potential as a global hub for clinical research. Pharmaceutical companies and Clinical Research Organization (CROs will require many trained personnel to carry out the clinical research. Keeping in mind these facts a CME with the theme of “Clinical research” had been jointly organized by the Dept of pharmacology, K.L.E University’s J.N.M.C, Belgaum and Indian Pharmacological Society (I.P.S, Belgaum branch on 20th February 2010. In the first scientific session, Dr.P.A.Patil (JNMC spoke on “Preclinical studies”. In vitro and in vivo experiments of various doses of ‘study drug’ can obtain preliminary efficacy, toxicity and pharmacokinetic information suggesting the scientific merit for further development as an investigational new drug (IND. Local or systemic toxicity studies can be conducted (ex: urine analysis, blood biochemical assay, gross and microscopic pathology etc. Dr. B.J. Mahendra Kumar (KLE University’s College of pharmacy talked on “Role of Drug Controller General of India (DCGI in Clinical Trials”. He explained about Drug and cosmetic acts/rules, requirements/guidelines for permission to import and/or to manufacture new drugs or to undertake clinical trials i.e. Schedule Y and its appendices. Dr.N.M.Patil (JNMC elaborated about “Ethical issues in clinical trials”. Ethics is required to: avoid exploitation of the subjects (maintain safety and wellbeing, protect vulnerable groups, children, disabled, elderly etc. Independent Ethics Committees (IEC and Institutional Review Boards (IRB are concerned with medical ethics. IECs review, regulate

  1. Basic flow structure in saccular aneurysms: a flow visualization study.

    Science.gov (United States)

    Steiger, H J; Poll, A; Liepsch, D; Reulen, H J

    1987-01-01

    Basic flow patterns were investigated in a set of glass aneurysm models by means of flow visualization methods. Dye injection and streaming double refraction were used to visualize flow. The circulation inside lateral aneurysms arising at a 90 degree angle from a straight parent conduit could not be visualized by the dye-injection technique but could be demonstrated by streaming double refraction. The inflow was seen to arise from the downstream lip of the orifice and to project to the dome of the aneurysm. Backflow to the parent conduit took place along the walls of the aneurysm. In aneurysms located at bifurcations, flow characteristics depended on the geometry of the bifurcation and the flow ratio between the branches. Relatively little intra-aneurysmal flow was demonstrated in side branch-related aneurysms arising distal to an asymmetric 90 degrees bifurcation of the type encountered at the junction of the internal carotid and posterior communicating arteries. Stagnation of flow at the neck and little intra-aneurysmal circulation were found with terminal aneurysms of the basilar bifurcation type if the outflow through the branches was symmetric. With asymmetric outflow, however, or if the axis of the aneurysm did not coincide with that of the afferent vessel, an active rotation developed in these aneurysms. The size of the aneurysm had no influence on the basic pattern of intra-aneurysmal circulation. The use of pulsatile perfusion did not significantly alter the basic flow patterns observed with steady flow. Locally disturbed laminar flow was observed in certain models at physiological Reynold's numbers, but there were no signs of fully developed turbulence.

  2. Intelligent Flow Friction Estimation.

    Science.gov (United States)

    Brkić, Dejan; Ćojbašić, Žarko

    2016-01-01

    Nowadays, the Colebrook equation is used as a mostly accepted relation for the calculation of fluid flow friction factor. However, the Colebrook equation is implicit with respect to the friction factor (λ). In the present study, a noniterative approach using Artificial Neural Network (ANN) was developed to calculate the friction factor. To configure the ANN model, the input parameters of the Reynolds Number (Re) and the relative roughness of pipe (ε/D) were transformed to logarithmic scales. The 90,000 sets of data were fed to the ANN model involving three layers: input, hidden, and output layers with, 2, 50, and 1 neurons, respectively. This configuration was capable of predicting the values of friction factor in the Colebrook equation for any given values of the Reynolds number (Re) and the relative roughness (ε/D) ranging between 5000 and 10(8) and between 10(-7) and 0.1, respectively. The proposed ANN demonstrates the relative error up to 0.07% which had the high accuracy compared with the vast majority of the precise explicit approximations of the Colebrook equation.

  3. THE INFLUENCED FLOW REGIMES

    Directory of Open Access Journals (Sweden)

    Gavril PANDI

    2011-03-01

    Full Text Available The influenced flow regimes. The presence and activities ofhumanity influences the uniform environmental system, and in this context, therivers water resources. In concordance with this, the natural runoff regime suffersbigger and deeper changes. The nature of these changes depending on the type anddegree of water uses. The multitude of the use cause different types of influence,whit different quantitative aspects. In the same time, the influences havequalitative connotations, too, regarding to the modifications of the yearly watervolume runoff. So the natural runoff regime is modified. After analyzing thedistribution laws of the monthly runoff, there have been differenced four types ofinfluenced runoff regimes. In the excess type the influenced runoff is bigger thanthe natural, continuously in the whole year. The deficient type is characterized byinverse rapports like the first type, in the whole year. In the sinusoidal type, theinfluenced runoff is smaller than the natural in the period when the water isretained in the lake reservoirs, and in the depletion period the situation inverts. Atthe irregular type the ratio between influenced and natural runoff is changeable ina random meaner monthly. The recognition of the influenced regime and the gradeof influence are necessary in the evaluation and analysis of the usable hydrologicalriver resources, in the flood defence activities, in the complex scheme of thehydrographic basins, in the environment design and so on.

  4. Turbomachinery Flows Modeled

    Science.gov (United States)

    Adamczyk, John J.

    1997-01-01

    Last year, researchers at the NASA Lewis Research Center used the average passage code APNASA to complete the largest three-dimensional simulation of a multistage axial flow compressor to date. Consisting of 29 blade rows, the configuration is typical of those found in aeroengines today. The simulation, which was executed on the High Performance Computing and Communications (HPCC) Program IBM SP2 parallel computer located at the NASA Ames Research Center, took nearly 90 hr to complete. Since the completion of this activity, a fine-grain, parallel version of APNASA has been written by a team of researchers from General Electric, NASA Lewis, and NYMA. Timing studies performed on the SP2 have shown that, with eight processors assigned to each blade row, the simulation time is reduced by a factor of six. For this configuration, the simulation time would be 15 hr. The reduction in computing time indicates that an overnight turnaround of a multistage configuration simulation is feasible. In addition, average passage forms of two-equation turbulence models were formulated. These models are currently being incorporated into APNASA.

  5. Intelligent Flow Friction Estimation

    Directory of Open Access Journals (Sweden)

    Dejan Brkić

    2016-01-01

    Full Text Available Nowadays, the Colebrook equation is used as a mostly accepted relation for the calculation of fluid flow friction factor. However, the Colebrook equation is implicit with respect to the friction factor (λ. In the present study, a noniterative approach using Artificial Neural Network (ANN was developed to calculate the friction factor. To configure the ANN model, the input parameters of the Reynolds Number (Re and the relative roughness of pipe (ε/D were transformed to logarithmic scales. The 90,000 sets of data were fed to the ANN model involving three layers: input, hidden, and output layers with, 2, 50, and 1 neurons, respectively. This configuration was capable of predicting the values of friction factor in the Colebrook equation for any given values of the Reynolds number (Re and the relative roughness (ε/D ranging between 5000 and 108 and between 10−7 and 0.1, respectively. The proposed ANN demonstrates the relative error up to 0.07% which had the high accuracy compared with the vast majority of the precise explicit approximations of the Colebrook equation.

  6. Biomimetic Flow Control

    Science.gov (United States)

    Anders, John B.

    2000-01-01

    Biologic flight has undoubtedly intrigued man for thousands of years, yet it has been only the last 100 years or so that any serious challenge has been mounted to the pre-eminence of birds. Although present-day large-scale aircraft are now clearly able to fly higher, faster and farther than any bird or insect, it is obvious that these biological creatures have a mastery of low Reynolds number, unsteady flows that is unrivaled by man-made systems. This paper suggests that biological flight should be examined for mechanisms that may apply to engineered flight systems, especially in the emerging field of small-scale, uninhabited aerial vehicles (UAV). This paper discusses the kinematics and aerodynamics of bird and insect flight, including some aspects of unsteady aerodynamics. The dynamics of flapping wing flight is briefly examined, including gait selection, flapping frequency and amplitude selection, as well as wing planform and angle-of-attack dynamics. Unsteady aerodynamic mechanisms as practiced by small birds and insects are reviewed. Drag reduction morphologies of birds and marine animals are discussed and fruitful areas of research are suggested.

  7. Filthy flows the Ganga.

    Science.gov (United States)

    D'monte, D

    1996-01-01

    The Ganga rises in the Himalayas and flows eastward, passing through Bangladesh, into the sea. It brings sustenance to the Indo-Gangetic plain and its basin inhabited by a little over a third of India's population. For the Indians, this river symbolizes its ancient culture and spirituality, but is treated with disrespect physically. Although devout Hindus still pay obeisance to this holiest of rivers, it has become almost synonymous with pollution and filth. A total of 27 major towns dump millions of liters of sewage and industrial waste into the river every day, which is compounded by the age-old belief that the Ganga has some magical self-cleansing properties, absorbing any amount of contamination. Some of the pollution contributors include tanneries emptying toxic chrome into the river, funeral pyres and half-burnt bodies, irrigation and siltation. To combat the pollution of the river, the Ganga Action Plan was launched a decade ago. However, this has failed because of the major reason of nonparticipation of people along the river. The participation of the community is needed to achieve success. In addition, there is a poor record of administration, reflected in the indifferent progress made in cleaning up the Ganga.

  8. Intelligent Flow Friction Estimation.

    Science.gov (United States)

    Brkić, Dejan; Ćojbašić, Žarko

    2016-01-01

    Nowadays, the Colebrook equation is used as a mostly accepted relation for the calculation of fluid flow friction factor. However, the Colebrook equation is implicit with respect to the friction factor (λ). In the present study, a noniterative approach using Artificial Neural Network (ANN) was developed to calculate the friction factor. To configure the ANN model, the input parameters of the Reynolds Number (Re) and the relative roughness of pipe (ε/D) were transformed to logarithmic scales. The 90,000 sets of data were fed to the ANN model involving three layers: input, hidden, and output layers with, 2, 50, and 1 neurons, respectively. This configuration was capable of predicting the values of friction factor in the Colebrook equation for any given values of the Reynolds number (Re) and the relative roughness (ε/D) ranging between 5000 and 10(8) and between 10(-7) and 0.1, respectively. The proposed ANN demonstrates the relative error up to 0.07% which had the high accuracy compared with the vast majority of the precise explicit approximations of the Colebrook equation. PMID:27127498

  9. Computerised triage in a prostate assessment clinic.

    Science.gov (United States)

    Rajkumar, G N; Small, D R; Conn, I G

    2004-01-01

    An MS Office package has been developed to score IPSS, take a patient history, compare flows with nomograms and decide on interim management. This is based on these scores, residual volume and laboratory results. A clearly formatted GP letter is produced. The patient uses a touch screen to answer questions on the IPSS and other medical history. These questions and responses are stored in Excel spread sheets. Clinic staff then enter results of flow studies, urinalysis, U&E and PSA. Excel Visual Basic creates a detailed printout for the notes and the MS Office mail merge facility creates a summary printout, which also serves as a letter to the GP. Excel allows embedding of formulae and program code to implement the rules for management. Based on these rules, the program either generates a request for an urgent appointment in the clinic or recommends the use of either an alpha blocker (if not contraindicated by medical history) or 5 alpha reductase inhibitors in the interim period before they are reviewed in clinic. A total of 139 patients have been seen and the computer decisions compared with those of a consultant urologist. Agreement was found in 106, disagreement in 33. However, 21 of the 33 involved computer oversensitivity to flow results. We do not anticipate difficulty improving this and are investigating using an artificial neural network. Of the other 12 patients, the urologist departed from the fixed rules for IPSS, creatinine, PSA and residual urine when only one variable was slightly abnormal. To conclude, this novel user-friendly system shows great potential in the management of prostate outpatients. Some tuning is needed, with particular respect to uroflow results. PMID:15175663

  10. Stochastic modeling for magnetic resonance quantification of myocardial blood flow

    Science.gov (United States)

    Seethamraju, Ravi T.; Muehling, Olaf; Panse, Prasad M.; Wilke, Norbert M.; Jerosch-Herold, Michael

    2000-10-01

    Quantification of myocardial blood flow is useful for determining the functional severity of coronary artery lesions. With advances in MR imaging it has become possible to assess myocardial perfusion and blood flow in a non-invasive manner by rapid serial imaging following injection of contrast agent. To date most approaches reported in the literature relied mostly on deriving relative indices of myocardial perfusion directly from the measured signal intensity curves. The central volume principle on the other hand states that it is possible to derive absolute myocardial blood flow from the tissue impulse response. Because of the sensitivity involved in deconvolution due to noise in measured data, conventional methods are sub-optimal, hence, we propose to use stochastic time series modeling techniques like ARMA to obtain a robust impulse response estimate. It is shown that these methods when applied for the optical estimation of the transfer function give accurate estimates of myocardial blood flow. The most significant advantage of this approach, compared with compartmental tracer kinetic models, is the use of a minimum set of prior assumptions on data. The bottleneck in assessing myocardial blood flow, does not lie in the MRI acquisition, but rather in the effort or time for post processing. It is anticipated that the very limited requirements for user input and interaction will be of significant advantage for the clinical application of these methods. The proposed methods are validated by comparison with mean blood flow measurements obtained from radio-isotope labeled microspheres.

  11. Clinical significance of microembolus detection by transcranial Doppler sonography in cardiovascular clinical conditions.

    Science.gov (United States)

    Hudorović, Narcis

    2006-01-01

    Transcranial Doppler can detect microembolic signals, which are characterized by unidirectional high intensity increase, short duration, and random occurrence, producing a "whistling" sound. Microembolic signals have been proven to represent solid or gaseous particles within the blood flow. Microemboli have been detected in a number of clinical cardiovascular settings: carotid artery stenosis, aortic arch plaques, atrial fibrillation, myocardial infarction, prosthetic heart valves, patent foramen ovale, valvular stenosis, during invasive procedures (angiography, percutaneous transluminal angioplasty) and surgery (carotid, cardiopulmonary bypass). Despite numerous studies performed so far, clinical significance of microembolic signals is still unclear. This article provides an overview of the development and current state of technical and clinical aspects of microembolus detection. PMID:17462357

  12. Fidelity in clinical simulation

    DEFF Research Database (Denmark)

    Jensen, Sanne; Nøhr, Christian; Rasmussen, Stine Loft

    2013-01-01

    Clinical simulation may be used to identify user needs for context sensitive functionalities in e-Health. The objective with this paper is to describe how user requirements and use cases in a large EHR-platform procurement may be validated by clinical simulation using a very low-fidelity prototype...... without any existing test data. Instead of using test scenarios and use cases, the healthcare professionals who are participating in the clinical simulation are generating both scenario and patient data themselves. We found that this approach allows for an imaginative discussion, not restricted by known...... functionalities and limitations, of the ideal EHR-platform. Subsequently, we discuss benefits and challenges of using an extremely low fidelity environment and discuss the degree of fidelity necessary for conducting clinical simulation....

  13. Participating in Clinical Trials

    Medline Plus

    Full Text Available ... experimental drug, therapy, medical device, lifestyle change, or test will help treat, find, or prevent a disease. A clinical trial may compare experimental products or tests to those already available or may compare existing ...

  14. Clinical Case Registries (CCR)

    Data.gov (United States)

    Department of Veterans Affairs — The Clinical Case Registries (CCR) replaced the former Immunology Case Registry and the Hepatitis C Case Registry with local and national databases. The CCR:HIV and...

  15. Clinical specular microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Hirst, L.W.; Laing, R.A.

    1987-01-01

    This book provides the general ophthalmologist with a guide to the clinical applications of specular microscopy. Important material is included on laser injury, cataract surgery, corneal transplants, glaucoma, uveitis, and trauma.

  16. Participating in Clinical Trials

    Medline Plus

    Full Text Available ... Clinical Trials Videos quiz yourself MedlinePlus for More Information National Institute on Aging Related Topics Talking with Your Doctor Taking Medicines The information in this topic was provided by the National ...

  17. Health Clinic Cost Reports

    Data.gov (United States)

    U.S. Department of Health & Human Services — Healthcare Cost Report Information System (HCRIS) Dataset - Independent Rural Health Clinic and Freestanding Federally Qualified Health Center (HCLINIC).This data...

  18. Leprosy neuropathy: clinical presentations.

    Science.gov (United States)

    Nascimento, Osvaldo J M

    2013-09-01

    Leprosy is a chronic infectious peripheral neuropathy caused by Mycobacterium leprae. The different clinical presentations of the disease are determined by the quality of the host immune response. Early detection of leprosy and treatment by multidrug therapy are the most important steps in preventing deformity and disability. Thus the early recognition of the clinical leprosy presentation is essential. Mononeuritis, mononeuritis multiplex (MM), polyneuritis (MM summation) are the most frequent. The frequent anesthetic skin lesions are absent in the pure neuritic leprosy presentation form. Isolated peripheral nerve involvement is common, including the cranial ones. Arthritic presentation is occasionally seen, usually misdiagnosed as rheumatoid arthritis. Attention should be given to autonomic dysfunctions in leprosy. There are clinical presentations with severe neuropathic pain - painful small-fiber neuropathy. Leprous late-onset neuropathy (LLON) clinical presentation should be considered facing a patient who develop an inflammatory neuropathy many years after a previous skin leprosy treatment. PMID:24141500

  19. Understanding Clinical Alarm Safety.

    Science.gov (United States)

    Lukasewicz, Carol L; Mattox, Elizabeth Andersson

    2015-08-01

    Patient safety organizations and health care accreditation agencies recognize the significance of clinical alarm hazards. The Association for the Advancement of Medical Instrumentation, a nonprofit organization focused on development and use of safe and effective medical equipment, identifies alarm management as a major issue for health care organizations. ECRI Institute, a nonprofit organization that researches approaches for improving patient safety and quality of care, identifies alarm hazards as the most significant of the "Top Ten Health Technology Hazards" for 2014. A new Joint Commission National Patient Safety Goal focusing on clinical alarm safety contains new requirements for accredited hospitals to be fully implemented by 2016. Through a fictional unfolding case study, this article reviews selected contributing factors to clinical alarm hazards present in inpatient, high-acuity settings. Understanding these factors improves contributions by nurses to clinical alarm safety practice.

  20. Participating in Clinical Trials

    Medline Plus

    Full Text Available ... that could identify a disease in its early stages. Usually, trial participants must show signs of the ... Trials Clinical trials of drugs are usually described based on their phase. The U.S. Food and Drug ...

  1. Transgressive first clinical experiences

    DEFF Research Database (Denmark)

    Jensen, Carsten Juul; Jeppesen, Lise Kofoed; Drachmann, Merete

    2014-01-01

    . The nursing students’ learning seems to be oriented towards socialization in the clinic as a workplace. This means that the nursing students seek to deal with overwhelming experiences concerning the naked bodies of patients and death, useful application of theoretical knowledge, the path from novice...... to advanced beginner, and adjusting to the workplace community. The conclusion is that the learning of nursing students during their first clinical in-service placement appears informal and not founded on evident best practice.......This Study seeks to comprehend learning experiences of nursing students during their first clinical in-service placement. This Paper is part of a longitudinal development project interviewing the Student Nurse after each one of the five clinical in-service placements and then one year after...

  2. OARSI Clinical Trials Recommendations

    DEFF Research Database (Denmark)

    Kraus, V B; Blanco, F J; Englund, M;

    2015-01-01

    The objective of this work was to describe requirements for inclusion of soluble biomarkers in osteoarthritis (OA) clinical trials and progress toward OA-related biomarker qualification. The Guidelines for Biomarkers Working Group, representing experts in the field of OA biomarker research from...... both academia and industry, convened to discuss issues related to soluble biomarkers and to make recommendations for their use in OA clinical trials based on current knowledge and anticipated benefits. This document summarizes current guidance on use of biomarkers in OA clinical trials...... and their utility at five stages, including preclinical development and phase I to phase IV trials. As demonstrated by this summary, biomarkers can provide value at all stages of therapeutics development. When resources permit, we recommend collection of biospecimens in all OA clinical trials for a wide variety...

  3. ClinicalTrials.gov

    Data.gov (United States)

    U.S. Department of Health & Human Services — Provides patients, family members, health care professionals, and members of the public easy access to information on clinical trials for a wide range of diseases...

  4. Participating in Clinical Trials

    Medline Plus

    Full Text Available ... Learn More Participating in Clinical Trials Videos quiz yourself MedlinePlus for More Information National Institute on Aging Related Topics Talking with Your Doctor Taking Medicines The information in ...

  5. Clinical evaluation of contemporary oxygenators.

    Science.gov (United States)

    Stanzel, Roger D P; Henderson, Mark

    2016-01-01

    Advances in cardiopulmonary bypass equipment have played a critical role in improving outcomes for cardiac surgery patients. Recent advancements include reduced priming volumes, biocompatible coatings and gaseous microemboli handling, as well as the incorporation of an arterial filter into the oxygenator.The purpose of this study was to conduct a comprehensive clinical evaluation of adult oxygenators on the market. Oxygenators assessed included the Sorin Synthesis(®) (n = 30), the Sorin Inspire 6F(®) (n = 10) and Inspire 8F(®) (n = 30), the Terumo FX15(®) (n = 13) and FX25(®) (n = 30), the Maquet Quadrox-i(®) (n = 30) and the Medtronic Fusion(®) (n = 30). Parameters assessed included functional prime volumes, gas exchange, pressure gradients and the effects on patient hematology.The Synthesis had the largest functional prime volume (1426 ml), the FX15 the lowest (956 ml). The Inspire 6F, 8F and Fusion had the greatest O2 transfer. The Sorin oxygenators required the lowest sweep gas flows to obtain a PaCO2 of 40 mmHg. The Sorin oxygenators had the largest pressure gradients. While no differences were observed for hemoglobin and platelet levels post cross-clamp removal, the Sorin Synthesis and Inspire 8F had the largest increases in white blood cell (WBC) counts (122% and 141% of baseline, respectively) and neutrophils (162% and 185% of baseline, respectively).The data demonstrate that no single product is superior in all aspects. The choice of ideal oxygenator depends on the aspect(s) of oxygenator performance the perfusion team believes most clinically acceptable based on available data. PMID:26407816

  6. Ethernet Flow Monitoring with IPFIX

    NARCIS (Netherlands)

    Hofstede, Rick; Drago, Idilio; Sperotto, Anna; Pras, Aiko

    2011-01-01

    The increasing amount of network traffic and the huge bandwidth needed to carry it requires managers to use scalable solutions to monitor their networks. Nowadays, flow-based techniques, such as Cisco’s NetFlow, provide aggregated network data and an overview of network activity at the IP layer. How

  7. Modeling of curvilinear suspension flows

    Science.gov (United States)

    Morris, Jeffrey F.; Boulay, Fabienne

    1996-11-01

    The curvilinear parallel-plate and cone-and-plate rheometric flows of monodisperse noncolloidal suspensions have been modeled. Although nonuniform in shear rate, dotγ, the parallel-plate flow has been shown experimentally(A. W. Chow, S. W. Sinton, J. H. Iwayima & T. S. Stephens 1994 Phys. Fluids) 6, 2561. not to exhibit particle migration, contrary to predictions of prior suspension-flow modeling. Predictions of nonuniform particle volume fraction, φ, by the suspension-balance model(P. R. Nott & J. F. Brady 1994 J. Fluid Mech.) 275, 157. for parallel-plate and cone-and-plate flow without normal stress differences are presented. The ``nonmigration'' in parallel-plate flow may be attributed to bulk suspension normal stress differences: assuming the bulk stress has the form Σ ~ η dotγ Q(φ) with η the fluid viscosity, nonmigration is predicted for parallel-plate flow provided that Q_33 = (1/2) Q_11 at the bulk φ of interest, with 1 the flow direction and 3 the vorticity direction. Extending the model to include normal stress differences satisfying this requirement, a range of migration behavior is predicted for the cone-and-plate flow depending upon the ratio Q_11/Q_22.

  8. Information flow between stock indices

    OpenAIRE

    Okyu Kwon; Jae-Suk Yang

    2008-01-01

    Using transfer entropy, we observed the strength and direction of information flow between stock indices. We uncovered that the biggest source of information flow is America. In contrast, the Asia/Pacific region the biggest is receives the most information. According to the minimum spanning tree, the GSPC is located at the focal point of the information source for world stock markets.

  9. Redox Flow Batteries, a Review

    OpenAIRE

    Weber, Adam Z.

    2013-01-01

    Redox flow batteries are enjoying a renaissance due to their ability to store large amounts of electrical energy relatively cheaply and efficiently. In this review, we examine the components of redox flow batteries with a focus on understanding the underlying physical processes. The various transport and kinetic phenomena are discussed along with the most common redox couples.

  10. Continuous-Flow Centrifugal Separator

    Science.gov (United States)

    Waldron, Robert D.

    1988-01-01

    Apparatus combines principles of centrifugal and cyclone separators to control movement of solid or liquid particles suspended in flowing gas. Spinning disk contains radial channels, width varys as function of distance from center. Gas flows from outer ring around disk toward center. Particles in gas collected at periphery, center or both.

  11. Flow hydrodynamics in embankment breach

    Institute of Scientific and Technical Information of China (English)

    ZHAO Gensheng; VISSER Paul J; REN Yankai; UIJTTEWAAL Wim S J

    2015-01-01

    Breaching flow occurs during the breach development of the embankment, dike, earthen dam, landslide barrier, etc. and plays an import role in the breaching erosion as the driving force. According to the previous research, the breaching process can be classified into initiation phase, breach widening phase and breach deepening phase. Based on the breaching development classifications, the breaching flow can be seen as a special compound weir flow when the breach channel is in the relatively equilibrium condition. There were five physical flow models were designed in the hypothesis of rectangular shape and trapezoidal shape for the breach channel cross sections to study the breaching flow characteristics. The distributions of water level and velocity were measured and analysed in the breaching flows in overtopping condition and emerged condition. There were two helicoidal flows above the breach channel slopes and triangular hydraulic jump in the downstream of the breach channel in the overtopping condition and emerged condition. The hydraulic energy loss was calculated according to the breaching velocity and water level distribution in the upstream and downstream of the model. It is found that the test results of the breach flow physical model can be valuable to bring insight of the breaching process of embankment and make contributions to the validations and verifications of breach numerical models.

  12. Traffic flow modeling: a Genealogy

    NARCIS (Netherlands)

    Van Wageningen-Kessels, F.L.M.; Hoogendoorn, S.P.; Vuik, C.; Van Lint, J.W.C.

    2014-01-01

    80 years ago, Bruce Greenshields presented the first traffic flow model at the Annual Meeting of the Highway Research Board. Since then, many models and simulation tools have been developed. We show a model tree with four families of traffic flow models, all descending from Greenshields' model. The

  13. Local Control of Blood Flow

    Science.gov (United States)

    Clifford, Philip S.

    2011-01-01

    Organ blood flow is determined by perfusion pressure and vasomotor tone in the resistance vessels of the organ. Local factors that regulate vasomotor tone include myogenic and metabolic autoregulation, flow-mediated and conducted responses, and vasoactive substances released from red blood cells. The relative importance of each of these factors…

  14. Integrated flow field (IFF) structure

    Science.gov (United States)

    Pien, Shyhing M. (Inventor); Warshay, Marvin (Inventor)

    2012-01-01

    The present disclosure relates in part to a flow field structure comprising a hydrophilic part and a hydrophobic part communicably attached to each other via a connecting interface. The present disclosure further relates to electrochemical cells comprising the aforementioned flow fields.

  15. Streamline topology of axisymmetric flows

    DEFF Research Database (Denmark)

    Brøns, Morten

    Topological fluid mechanics in the sense of the present paper is the study and classification of flow patterns close to a critical point. Here we discuss the topology of steady viscous incompressible axisymmetric flows in the vicinity of the axis. Following previous studies the velocity field $v...

  16. Subcubic Control Flow Analysis Algorithms

    DEFF Research Database (Denmark)

    Midtgaard, Jan; Van Horn, David

    We give the first direct subcubic algorithm for performing control flow analysis of higher-order functional programs. Despite the long held belief that inclusion-based flow analysis could not surpass the ``cubic bottleneck, '' we apply known set compression techniques to obtain an algorithm...

  17. Polygonal instability of Marangoni flows

    Science.gov (United States)

    Roché, Matthieu; Labousse, Matthieu; El Hadj Maiga, Baba; Nya, Loïc; Le Roux, Sébastien; Cantat, Isabelle; Saint-Jalmes, Arnaud

    2015-11-01

    The transport of pepper grains floating at the surface of a bowl of water after the release of a drop of dishwashing liquid is a classical experiment to demonstrate the Marangoni effect, i.e. the flow of a liquid layer induced by interfacial tension gradients at its surface. In this case, the interfacial tension gradient results from a surfactant interfacial concentration gradient. Recently, we showed that continuous injection of an aqueous solution of hydrosoluble surfactants at the surface of a cm-thick pure water layer induced finite-size Marangoni flows surrounded by a region characterized by the presence of several pairs of interfacial vortices arranged along the the vertices of polygons. During this talk, I will show that we can understand the flow structure induced by these Marangoni flows, in particular their tendency to have polygonal shapes. I will describe how flow features such as the number of interfacial vortices or bulk recirculation flows depend on flow geometry. Finally, I will compare these results to a model that explains similar polygonal instabilities in other flows such as the hydraulic jump.

  18. Supersonic flow imaging via nanoparticles

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Due to influence of compressibility,shock wave,instabilities,and turbulence on supersonic flows, current flow visualization and imaging techniques encounter some problems in high spatiotemporal resolution and high signal-to-noise ratio(SNR)measurements.Therefore,nanoparticle based planar laser scattering method(NPLS)is developed here.The nanoparticles are used as tracer,and pulse planar laser is used as light source in NPLS;by recording images of particles in flow field with CCD, high spatiotemporal resolution supersonic flow imaging is realized.The flow-following ability of nanoparticles in supersonic flows is studied according to multiphase flow theory and calibrating experiment of oblique shock wave.The laser scattering characteristics of nanoparticles are analyzed with light scattering theory.The results of theoretical and experimental studies show that the dynamic behavior and light scattering characteristics of nanoparticles highly enhance the spatiotemporal resolution and SNR of NPLS,with which the flow field involving shock wave,expansion,Mach disk,boundary layer,sliding-line,and mixing layer can be imaged clearly at high spatiotemporal resolution.

  19. Supersonic flow imaging via nanoparticles

    Institute of Scientific and Technical Information of China (English)

    ZHAO YuXin; YI ShiHe; TIAN LiFeng; CHENG ZhongYu

    2009-01-01

    Due to influence of compressibility,shock wave,instabilities,and turbulence on supersonic flows,current flow visualization and imaging techniques encounter some problems in high spatiotemporal resolution and high signal-to-noise ratio(SNR)measurements.Therefore,nanoparticle based planar laser scattering method(NPLS)is developed here.The nanoparticles are used as tracer,and pulse planar laser is used as light source in NPLS;by recording images of particles in flow field with CCD,high spatiotemporal resolution supersonic flow imaging is realized.The flow-following ability of nanoparticles in supersonic flows is studied according to multiphase flow theory and calibrating experiment of oblique shock wave.The laser scattering characteristics of nanoparticles are analyzed with light scattering theory.The results of theoretical and experimental studies show that the dynamic behavior and light scattering characteristics of nanoparticles highly enhance the spatiotemporal resolution and SNR of NPLS,with which the flow field involving shock wave,expansion,Mach disk,boundary layer,sliding-line,and mixing layer can be imaged clearly at high spatiotemporal resolution.

  20. Investor Flows to Asset Managers

    DEFF Research Database (Denmark)

    Christoffersen, Susan E. K.; Musto, David K.; Wermers, Russ

    2014-01-01

    of the financial system and the real economy, and the retirement security and protection of the investors. There is an accordingly large and growing literature on flows that has concentrated on the main retail investment pool, the open-end mutual fund, and has used flows to explore many aspects of retail financial...