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Sample records for clinical quatitative flow

  1. A model for harmonizing flow cytometry in clinical trials.

    Science.gov (United States)

    Maecker, Holden T; McCoy, J Philip; Amos, Michael; Elliott, John; Gaigalas, Adolfas; Wang, Lili; Aranda, Richard; Banchereau, Jacques; Boshoff, Chris; Braun, Jonathan; Korin, Yael; Reed, Elaine; Cho, Judy; Hafler, David; Davis, Mark; Fathman, C Garrison; Robinson, William; Denny, Thomas; Weinhold, Kent; Desai, Bela; Diamond, Betty; Gregersen, Peter; Di Meglio, Paola; DiMeglio, Paola; Nestle, Frank O; Nestle, Frank; Peakman, Mark; Villanova, Federica; Villnova, Federica; Ferbas, John; Field, Elizabeth; Kantor, Aaron; Kawabata, Thomas; Komocsar, Wendy; Lotze, Michael; Nepom, Jerry; Ochs, Hans; O'Lone, Raegan; Phippard, Deborah; Plevy, Scott; Rich, Stephen; Roederer, Mario; Rotrosen, Dan; Yeh, Jung-Hua

    2010-11-01

    Complexities in sample handling, instrument setup and data analysis are barriers to the effective use of flow cytometry to monitor immunological parameters in clinical trials. The novel use of a central laboratory may help mitigate these issues.

  2. 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.

  3. Multiparameter Flow Cytometry For Clinical Applications

    Science.gov (United States)

    Stewart, Carleton C.

    1989-06-01

    Flow Cytometry facilities are well established and provide immunophenotyping and DNA content measurement services. The application of immunophenotyping has been primarily in monitoring therapy and in providing further information to aid in the definitive diagnosis of immunological and neoplastic disease such as: immunodeficiency disease, auto immune disease, organ transplantation, and leukemia and lymphoma. DNA content measurements have been particularly important in determining the fraction of cycling cells and presence of aneuploid cells in neoplasia. This information has been useful in the management of patients with solid tumors.

  4. Bulk flow and diffusion revisited, and clinical applications.

    Science.gov (United States)

    Reulen, Hans-J

    2010-01-01

    The first Klatzo-Lecture pays homage to an exceptional academician, scientist and teacher. The author spent nearly 1 year in Klatzo's laboratory at the NHI in Bethesda, and the first part of results presented here originate directly from this collaboration. It was shown that following cortical injury, movement of edema fluid into the tissue occurs by bulk flow, and that the driving force is a small tissue pressure gradient. Resolution of edema fluid is achieved by clearance into the ventricular and subarachnoid CSF, is enhanced in the presence of pressure gradients and is supported by re-absorption into capillaries. Using appropriate techniques, the formation rate as well as clearance of edema into CSF and tissue resorption could be determined in human brain metastases and malignant gliomas. Three examples of clinical applications based on the discussed mechanisms are presented: a. Fluorescence-guided surgery of gliomas is based on the accumulation of 5-ALA in tumour cells; there being enzymatically converted to PP-IX, a compound with deep red fluorescence. This fluorescence is used for the more accurate surgical removal of gliomas. b. Radioimmunotherapy of gliomas uses an anti-tenascin antibody, coupled with a nuclide, administered postoperatively into the tumour cavity, from where it diffuses into tissue, couples to the receptor at the glioma cells. Then the isotope destroys the tumour cells. c. Convection-enhanced delivery is based on the interstitial infusion of an appropriate cytotoxic drug into the white matter at low pressure. Thus, the method employs bulk flow, distributes a drug in a larger tissue volume and eventually achieves drug concentrations greater than systemic levels. Experimental studies and clinical results are presented for all three clinical applications.I am very grateful to Z. Czernicki and the organizing group for being offered the great honour of presenting the first Igor Klatzo Lecture. In this report first previous results of bulk flow

  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. Indigenous development of an imaging flow cytometer for clinical and biological applications

    Science.gov (United States)

    J, Veerendra Kalyan; Srinivasan, Rajesh; Gorthi, Sai Siva

    2014-10-01

    Flow cytometry is a benchmark technique used for basic research and clinical diagnosis of various diseases. Despite being a high-throughput technique, it fails in capturing the morphology of cells being analyzed. Imaging flow cytometry is a combination of flow-cytometry and digital microscopy, which offers advantages of both the techniques. In this paper, we report on the development of an indigenous Imaging Flow Cytometer, realized with the combination of Optics, Microfluidics, and High-speed imaging. A custom-made bright-field transmission microscope is used to capture images of cells flowing across the microfluidic device. High-throughput morphological analysis on suspension of yeast cells is presented.

  7. 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...... of agreement between results from the ReoCath Flow Catheter System and the reference flowmeter. Clinical precision, expressed as the mean coefficient of variation, was 5.9% and 4.7% for the antegrade and retrograde catheters, respectively. Flow measurements were significantly affected by the distance between...... a stenosis and the tip of a retrograde catheter with the effect being proportional to the degree of stenosis. There was no systematic bias between measurers. Conclusions: The Reocath Flow Catheter System was found to be accurate and precise. Reliable results require careful attention to catheter placement...

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

    OpenAIRE

    Iole Macchia; Francesca Urbani; Enrico Proietti

    2013-01-01

    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 cytometr...

  9. Clinical use of optical coherence tomography and fractional flow reserve

    Directory of Open Access Journals (Sweden)

    Ivanović Vladimir

    2016-01-01

    Full Text Available Introduction. The aim of each diagnostic method is to serve as a guide in deciding about the right patient treatment. During myocardial revascularization the decision to perform revascularization is usually not easy to make, especially in case of borderline stenosis. It has been proven that it is not enough to base morphological evaluation of coronary artery vessel stenosis solely on angiography. It is necessary to include additional modern diagnostic methods for functional analysis and detailed morphological analysis using fractional flow reserve (FFR and optical coherence tomography (OCT, respectively. Case reports. In the first case report we showed the significance of morphological analysis using OCT and proved that it was not lumen stenosis. The second and the third case reports showed the complementarity between functional analysis (FFR and morphological analysis (OCT of stenosis in solving a complex coronary disease. The fourth case report showed the significance of OCT in dealing with the recurrent stent restenosis. Conclusion. By these short case reports we confirmed that percutaneous coronary intervention (PCI guided by angiography is definitely not enough in deciding about myocardial revascularization especially in patients with a complex coronary disease. In certain cases FFR and OCT procedures can be complementary methods and improve quality of revascularization, particularly in the case of recurrent in-stent restenosis.

  10. 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.

  11. Improved flow measurement using microbubble contrast agents and disruption-replenishment: clinical application to tumour monitoring.

    Science.gov (United States)

    Hudson, John M; Williams, Ross; Lloyd, Brendan; Atri, Mostafa; Kim, Tae Kyoung; Bjarnason, Georg; Burns, Peter N

    2011-08-01

    Dynamic contrast-enhanced ultrasound (DCE-US) and the method of disruption replenishment has been used for the past 10 years to measure flow noninvasively in the microcirculation. However, the method's perceived poor reproducibility remains a major impediment to widespread clinical acceptance. Poor reproducibility can be attributed, in part, to the curve fitting model that is used to quantify microbubble enhancement. Flow measurement in tumours is further complicated by the spatial and temporal heterogeneity of tumour blood flow. In this work, we evaluate three models of microbubble disruption and replenishment (mono-exponential, a simplified multivessel model by Krix and the lognormal perfusion model) using clinical data (11 patients, 41 sessions) from an antiangiogenic drug trial for metastatic renal cell carcinoma (RCC) and evaluate their contribution to the measurement's variability. Compared with the mono-exponential model, the lognormal perfusion model decreased the variability of intra-session velocity and blood volume measurements by 33% and 34%, respectively. Blood volume assessment using the lognormal perfusion model was comparable to Krix's mutlivessel model. Flow velocity measurement was 18% less variable for the lognormal perfusion model compared with the multivessel model. To further decrease flow measurement variability, we examine a method that exploits microbubble flow dynamics to discard the contribution of flow in large arteries and isolate the portion of the tumour microvasculature that is most sensitive to vessel targeting therapies. The method is validated with an in vitro phantom study prior to its application to the RCC clinical data set. Combined with the lognormal perfusion model, this method decreased the inter-plane variability of clinical measurements of relative tumour blood volume, in some cases by up to 20%.

  12. 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.

  13. 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.

  14. The basophil activation test by flow cytometry: recent developments in clinical studies, standardization and emerging perspectives

    Directory of Open Access Journals (Sweden)

    Debard Anne-Lise

    2005-06-01

    Full Text Available Abstract The diagnosis of immediate allergy is mainly based upon an evocative clinical history, positive skin tests (gold standard and, if available, detection of specific IgE. In some complicated cases, functional in vitro tests are necessary. The general concept of those tests is to mimic in vitro the contact between allergens and circulating basophils. The first approach to basophil functional responses was the histamine release test but this has remained controversial due to insufficient sensitivity and specificity. During recent years an increasing number of studies have demonstrated that flow cytometry is a reliable tool for monitoring basophil activation upon allergen challenge by detecting surface expression of degranulation/activation markers (CD63 or CD203c. This article reviews the recent improvements to the basophil activation test made possible by flow cytometry, focusing on the use of anti-CRTH2/DP2 antibodies for basophil recognition. On the basis of a new triple staining protocol, the basophil activation test has become a standardized tool for in vitro diagnosis of immediate allergy. It is also suitable for pharmacological studies on non-purified human basophils. Multicenter studies are now required for its clinical assessment in large patient populations and to define the cut-off values for clinical decision-making.

  15. The basophil activation test by flow cytometry: recent developments in clinical studies, standardization and emerging perspectives.

    Science.gov (United States)

    Boumiza, Radhia; Debard, Anne-Lise; Monneret, Guillaume

    2005-06-30

    The diagnosis of immediate allergy is mainly based upon an evocative clinical history, positive skin tests (gold standard) and, if available, detection of specific IgE. In some complicated cases, functional in vitro tests are necessary. The general concept of those tests is to mimic in vitro the contact between allergens and circulating basophils. The first approach to basophil functional responses was the histamine release test but this has remained controversial due to insufficient sensitivity and specificity. During recent years an increasing number of studies have demonstrated that flow cytometry is a reliable tool for monitoring basophil activation upon allergen challenge by detecting surface expression of degranulation/activation markers (CD63 or CD203c). This article reviews the recent improvements to the basophil activation test made possible by flow cytometry, focusing on the use of anti-CRTH2/DP2 antibodies for basophil recognition. On the basis of a new triple staining protocol, the basophil activation test has become a standardized tool for in vitro diagnosis of immediate allergy. It is also suitable for pharmacological studies on non-purified human basophils. Multicenter studies are now required for its clinical assessment in large patient populations and to define the cut-off values for clinical decision-making.

  16. 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.

  17. 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.

  18. 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.

  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. 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.

  1. 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

  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. Optimizing resource allocation and patient flow: process analysis and reorganization in three chemotherapy outpatient clinics.

    Science.gov (United States)

    Holmes, Morgan; Bodie, Kelly; Porter, Geoffrey; Sullivan, Victoria; Tarasuk, Joy; Trembley, Jodie; Trudeau, Maureen

    2010-01-01

    Optimizing human and physical resources is a major concern for cancer care decision-makers and practitioners. This issue is particularly acute in the context of ambulatory out patient chemotherapy clinics, especially when - as is the case almost everywhere in the industrialized world - the number of people requiring systemic therapy is increasing while budgets, staffing and physical space remain static. Recent initiatives at three hospital-based chemotherapy units - in Halifax, Toronto and Kingston - shed light on the value of process analysis and reorganization for using existing human and physical resources to their full potential, improving patient flow and enhancing patient satisfaction. The steps taken in these settings are broadly applicable to other healthcare settings and would likely result in similar benefits in those environments.

  4. Hepatosplenic T Cell Lymphoma in an Immunocompetent Female Diagnosed using Flow Cytometry: A Rare Clinical Entity.

    Science.gov (United States)

    Dorwal, Pranav; Sachdev, Ritesh; Pande, Amit; Jain, Dharmendra; Jha, Bhawna; Raina, Vimarsh

    2016-08-01

    Hepatosplenic T-cell lymphoma is a rare haematopoietic malignancy that comprises less than 1% of Non-Hodgkin lymphomas. We are reporting a case of a 26-year-old female, who presented with pallor, weight loss, jaundice, pancytopenia and hepatosplenomegaly. The bone marrow examination showed infiltration by lymphoid cells. These cells on flow cytometric evaluation showed the phenotype of hepatosplenic T cell lymphoma. The cells were positive for CD3, CD8, CD56 and TCR γδ and negative for CD5, CD4, CD8, CD16, CD57, TCRαβ along with B cell markers. This case is reported for being a rare clinical entity and its presence in an immunocompetent female making it rarer.

  5. 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...... meaningful subgroups of COPD in a group of 91 COPD patients with FEV(1) 17-77% of predicted. Multiple flow rates FeNO at 10, 30, 50, 100 and 200 mL/s were measured and a two-compartment model was used to estimate the diffusion Capacity (D), alveolar NO concentration (Calv) and airway wall NO concentration...... body mass and 5) Low fat-free mass index. We used advanced non-linear mixed model adjusted for age and gender. The modelled differences in D, Calv or Caw among COPD subgroups were small and not statistically significant. The analysis showed significant effects of current smoking on Caw and of gender...

  6. Circulating tumor cells: clinically relevant molecular access based on a novel CTC flow cell.

    Directory of Open Access Journals (Sweden)

    Jessamine P Winer-Jones

    Full Text Available BACKGROUND: Contemporary cancer diagnostics are becoming increasing reliant upon sophisticated new molecular methods for analyzing genetic information. Limiting the scope of these new technologies is the lack of adequate solid tumor tissue samples. Patients may present with tumors that are not accessible to biopsy or adequate for longitudinal monitoring. One attractive alternate source is cancer cells in the peripheral blood. These rare circulating tumor cells (CTC require enrichment and isolation before molecular analysis can be performed. Current CTC platforms lack either the throughput or reliability to use in a clinical setting or they provide CTC samples at purities that restrict molecular access by limiting the molecular tools available. METHODOLOGY/PRINCIPAL FINDINGS: Recent advances in magetophoresis and microfluidics have been employed to produce an automated platform called LiquidBiopsy®. This platform uses high throughput sheath flow microfluidics for the positive selection of CTC populations. Furthermore the platform quantitatively isolates cells useful for molecular methods such as detection of mutations. CTC recovery was characterized and validated with an accuracy (<20% error and a precision (CV<25% down to at least 9 CTC/ml. Using anti-EpCAM antibodies as the capture agent, the platform recovers 78% of MCF7 cells within the linear range. Non specific recovery of background cells is independent of target cell density and averages 55 cells/mL. 10% purity can be achieved with as low as 6 CTCs/mL and better than 1% purity can be achieved with 1 CTC/mL. CONCLUSIONS/SIGNIFICANCE: The LiquidBiopsy platform is an automated validated platform that provides high throughput molecular access to the CTC population. It can be validated and integrated into the lab flow enabling CTC enumeration as well as recovery of consistently high purity samples for molecular analysis such as quantitative PCR and Next Generation Sequencing. This tool opens

  7. Impact of the new Beckman Coulter Cytomics FC 500 5-color flow cytometer on a regional flow cytometry clinical laboratory service.

    Science.gov (United States)

    Luider, J; Cyfra, M; Johnson, P; Auer, I

    2004-01-01

    repeats, and interpretations, have been substantially reduced with the Cytomics FC 500 5-color flow cytometer. In conclusion the Cytomics FC 500 5-color flow cytometer is a major advance in flow cytometry instrumentation and has reduced our overall reagent costs by 20%, provided better information and speedier turnaround time to our health care professionals. It is an ideal flow cytometer for any busy clinical or research flow cytometry service.

  8. 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.

  9. The clinical utility and prognostic value of multiparameter flow cytometry immunophenotyping in light-chain amyloidosis.

    Science.gov (United States)

    Paiva, Bruno; Vídriales, María-Belén; Pérez, José J; López-Berges, María-Consuelo; García-Sanz, Ramón; Ocio, Enrique M; de Las Heras, Natalia; Cuello, Rebeca; García de Coca, Alfonso; Pardal, Emilia; Alonso, José; Sierra, Magdalena; Bárez, Abelardo; Hernández, José; Suárez, Lissbett; Galende, Josefina; Mateos, María-Victoria; San Miguel, Jesús F

    2011-03-31

    The clinical value of multiparameter flow cytometry (MFC) immunophenotyping in primary or light chain amyloidosis (AL) remains unknown. We studied 44 consecutive bone marrow samples from newly diagnosed patients with amyloidosis; 35 patients with AL and 9 with other forms of amyloidosis. Monoclonal plasma cells (PCs) were identifiable by MFC immunophenotyping in 34 of 35 (97%) patients with AL, whereas it was absent from all but 1 of the 9 (11%) patients with other forms of amyloidosis. Quantification of bone marrow plasma cells (BMPCs) by MFC immunophenotyping was a significant prognostic factor for overall survival (OS) (≤ 1% vs > 1% BMPC cutoff; 2-year OS rates of 90% vs 44%, P = .02). Moreover, detecting persistent normal PCs at diagnosis identifies a subgroup of patients with AL with prolonged OS (> 5% vs ≤ 5% normal PC within all BMPC cutoff, 2-year rates of 88% vs 37%, P = .01). MFC immunophenotyping could be clinically useful for the demonstration of PC clonality in AL and for the prognostication of patients with AL.

  10. SPECT myocardial blood flow quantitation toward clinical use: a comparative study with {sup 13}N-Ammonia PET myocardial blood flow quantitation

    Energy Technology Data Exchange (ETDEWEB)

    Hsu, Bailing [University of Missouri-Columbia, Nuclear Science and Engineering Institute, Columbia, Missouri (United States); Hu, Lien-Hsin; Yang, Bang-Hung; Ting, Chien-Hsin; Huang, Wen-Sheng [Taipei Veterans General Hospital, Department of Nuclear Medicine, Taipei (China); Chen, Lung-Ching [Shin Kong Wu-Ho Su Memorial Hospital, Division of Cardiology, Taipei (China); Chen, Yen-Kung [Shin Kong Wu-Ho Su Memorial Hospital, Department of Nuclear Medicine, Taipei (China); Hung, Guang-Uei [Chang Bing Show Chwan Memorial Hospital, Department of Nuclear Medicine, Changhua (China); Wu, Tao-Cheng [National Yang-Ming University, Cardiovascular Research Center, Taipei (China)

    2017-01-15

    The aim of this study was to evaluate the accuracy of myocardial blood flow (MBF) quantitation of {sup 99m}Tc-Sestamibi (MIBI) single photon emission computed tomography (SPECT) compared with {sup 13}N-Ammonia (NH3) position emission tomography (PET) on the same cohorts. Recent advances of SPECT technologies have been applied to develop MBF quantitation as a promising tool to diagnose coronary artery disease (CAD) for areas where PET MBF quantitation is not available. However, whether the SPECT approach can achieve the same level of accuracy as the PET approach for clinical use still needs further investigations. Twelve healthy volunteers (HVT) and 16 clinical patients with CAD received both MIBI SPECT and NH3 PET flow scans. Dynamic SPECT images acquired with high temporary resolution were fully corrected for physical factors and processed to quantify K1 using the standard compartmental modeling. Human MIBI tracer extraction fraction (EF) was determined by comparing MIBI K1 and NH3 flow on the HVT group and then used to convert flow values from K1 for all subjects. MIBI and NH3 flow values were systematically compared to validate the SPECT approach. The human MIBI EF was determined as [1.0-0.816*exp(-0.267/MBF)]. Global and regional MBF and myocardial flow reserve (MFR) of MIBI SPECT and NH3 PET were highly correlated for all subjects (global R{sup 2}: MBF = 0.92, MFR = 0.78; regional R{sup 2}: MBF ≥ 0.88, MFR ≥ 0.71). No significant differences for rest flow, stress flow, and MFR between these two approaches were observed (All p ≥ 0.088). Bland-Altman plots overall revealed small bias between MIBI SPECT and NH3 PET (global: ΔMBF = -0.03Lml/min/g, ΔMFR = 0.07; regional: ΔMBF = -0.07 - 0.06, ΔMFR = -0.02 - 0.22). Quantitation with SPECT technologies can be accurate to measure myocardial blood flow as PET quantitation while comprehensive imaging factors of SPECT to derive the variability between these two approaches were fully addressed and corrected

  11. 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.

  12. Intracellular Cytokine Staining and Flow Cytometry: Considerations for Application in Clinical Trials of Novel Tuberculosis Vaccines.

    Directory of Open Access Journals (Sweden)

    Steven G Smith

    Full Text Available Intracellular cytokine staining combined with flow cytometry is one of a number of assays designed to assess T-cell immune responses. It has the specific advantage of enabling the simultaneous assessment of multiple phenotypic, differentiation and functional parameters pertaining to responding T-cells, most notably, the expression of multiple effector cytokines. These attributes make the technique particularly suitable for the assessment of T-cell immune responses induced by novel tuberculosis vaccines in clinical trials. However, depending upon the particular nature of a given vaccine and trial setting, there are approaches that may be taken at different stages of the assay that are more suitable than other alternatives. In this paper, the Tuberculosis Vaccine Initiative (TBVI TB Biomarker Working group reports on efforts to assess the conditions that will determine when particular assay approaches should be employed. We have found that choices relating to the use of fresh whole blood or peripheral blood mononuclear cells (PBMC and frozen PBMC; use of serum-containing or serum-free medium; length of stimulation period and use of co-stimulatory antibodies can all affect the sensitivity of intracellular cytokine assays. In the case of sample material, frozen PBMC, despite some loss of sensitivity, may be more advantageous for batch analysis. We also recommend that for multi-site studies, common antibody panels, gating strategies and analysis approaches should be employed for better comparability.

  13. A clinical study on velocity patterns of pulmonary venous flow in canine heartworm disease.

    Science.gov (United States)

    Shibata, T; Wakao, Y; Takahashi, M

    2000-02-01

    In this study, we evaluated methods of determining the velocity patterns of pulmonary venous flow (PVF) in dogs and then investigated the relationship of the patterns to cardiac functions in heartworm disease (HD) by transthoracic echocardiography (TTE). The results revealed that there was a good correlation between PVF patterns determined by transesophageal echocardiography (TEE) and TTE in animals lying on their left sides. The measurement of S and D wave velocities (PVS and PVD) by TTE was shown to allow clinical determination of the velocity patterns of PVF in dogs. The HD groups showed significant increases in PVS and PVD, and S and D wave time-velocity integrals (S-TVI and D-TVI) of the right cranial lobe PVF, when compared with the normal group, as determined by TTE (P<0.05). In contrast, the HD groups produced significant decreases in PVD and D-TVI of the right caudal lobe PVF compared with the normal group (P<0.05), and a significant increase in the ratio of S-TVI to (S-TVI + D-TVI) (P<0.05). It is, therefore, suggested that measurement of the velocity patterns of the right cranial and caudal lobe PVF could be one method of assessing the stages of obstructive lesions in the pulmonary artery.

  14. Clinical and experimental aspects of functional and flow reserve of the myocardium

    NARCIS (Netherlands)

    E.O. McFalls (Edward)

    1991-01-01

    textabstractBasic research over the past 50 years has provided the clinician with important concepts for understanding human coronary physiology. One such tool is the determination of coronary blood flow reserve. Defined as the ratio of maximal to resting coronary flow, flow reserve may be helpful i

  15. Lesion flow coefficient: a combined anatomical and functional parameter for detection of coronary artery disease--a clinical study.

    Science.gov (United States)

    Peelukhana, Srikara V; Effat, Mohamed; Kolli, Kranthi K; Arif, Imran; Helmy, Tarek; Leesar, Massoud; Kerr, Hanan; Back, Lloyd H; Banerjee, Rupak

    2015-01-01

    Invasive diagnosis of coronary artery disease utilizes either anatomical or functional measurements. In this study, we tested a futuristic parameter, lesion flow coefficient (LFC, defined as the ratio of percent coronary area stenosis (%AS) to the square root of the ratio of the pressure drop across the stenosis to the dynamic pressure in the throat region), that combines both the anatomical (%AS) and functional measurements (pressure and flow) for application in a clinical setting. In 51 vessels, simultaneous pressure and flow readings were obtained using a 0.014" Combowire (Volcano Corporation). Anatomical details were assessed using quantitative coronary angiography (QCA). Fractional flow reserve (FFR), coronary flow reserve (CFR), hyperemic stenosis resistance index (HSR), and hyperemic microvascular index (HMR) were obtained at baseline and adenosine-induced hyperemia. QCA data were corrected for the presence of guidewire and then the LFC values were calculated. LFC was correlated with FFR, CFR, HSR, and HMR, individually and in combination with %AS, under both baseline and hyperemic conditions. Further, in 5 vessels, LFC group mean values were compared between pre-PCI and post-PCI groups. Panatomically measured %AS were combined (r = 0.64; Panatomical and functional endpoints, has potential for application in a clinical setting for stenosis evaluation, under both hyperemic and baseline conditions.

  16. 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...

  17. Clinical utility of flow cytometry in the study of erythropoiesis and nonclonal red cell disorders.

    Science.gov (United States)

    Chesney, Alden; Good, David; Reis, Marciano

    2011-01-01

    Erythropoiesis involves proliferation and differentiation of small population of hematopoietic stem cells resident in the bone marrow into mature red blood cells. The determination of the cellular composition of the blood is a valuable tool in the diagnosis of diseases and monitoring of therapy. Flow cytometric analysis is increasingly being used to characterize the heterogeneous cell populations present in the blood and the hematopoietic cell differentiation and maturation pathways of the bone marrow. Here we discuss the role of flow cytometry in the study of erythropoiesis and nonclonal red blood cell disorders. First, we discuss flow cytometric analysis of reticulocytes. Next, we review salient quantitative methods that can be used for detection of fetal-maternal hemorrhage (FMH). We also discuss flow cytometric analysis of high hemoglobin F (HbF) in Sickle Cell Disease (SCD), hereditary spherocytosis (HS), red cell survival and red cell volume. We conclude by discussing cell cycle of erythroid cells.

  18. Quantification of cerebral blood flow and its clinical usefulness. Application of SPECT to psychiatry

    Energy Technology Data Exchange (ETDEWEB)

    Matsuda, Hiroshi; Uema, Takeshi; Kogure, Daisuke; Takano, Harumasa; Terada, Tomo [National Center Hospital for Mental, Nervous and Muscular Disorders, Kodaira, Tokyo (Japan)

    1998-10-01

    Brain perfusion SPECT using {sup 99m}Tc-ethyl-cysteinate dimer ({sup 99m}Tc-ECD) was applied to psychiatric diseases with aid of statistical parametric mapping (SPM) for analysis of data. To evaluate influence of aging on brain perfusion, noninvasive measurements of cerebral blood flow using {sup 99m}Tc-ECD were performed in 53 normal volunteers, aged 18 to 87 years old. Mean cerebral blood flow (mCBF) was 43.9{+-}5.0 ml/100 g/min and showed weak negative correlation with aging (r=-0.451). Perisylvian cerebral cortices and medial frontal areas including anterior cingulate gyri showed greater negative correlation than other areas. These findings suggest the necessity of age-matched control regional CBF (rCBF) data to investigate rCBF abnormality in patients. Four drug-naive schizophrenic patients showed flow decrease in bilateral frontal and superior temporal areas and a left infero-posterior temporal area. Haloperidol administration induced flow decrease in bilateral frontal and left parietal areas, while flow increase in bilateral striatal and right hippocampal areas. Ten aged depressive patients showed flow decrease in bilateral frontal and left temporo-parietal areas. Even after remission patients showed flow decrease in the left frontal area as compared with normal subjects. Remission induced flow increase in the right frontal, right parietal, and right orbitofrontal areas compared with depression. These results suggest that CBF measurements using {sup 99m}Tc-ECD are useful for objective evaluation of regional abnormality in brain function in psychiatric diseases. (author)

  19. 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

  20. 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.

  1. The Diagnostic Value of Flow Cytometry Imunophenotyping in an Albanian Patient Population with a Preliminary Clinical Diagnosis of Chronic Lymphocytic Leukemia

    Directory of Open Access Journals (Sweden)

    Valentina Semanaj

    2014-03-01

    Conclusion: Flow cytometry immunophenotyping is a fundamental examination for the final diagnosis of chronic lymphocytic leukemia. The expression of CD38+ in CLL patients stands for a more advanced clinical stage.

  2. Clinical study of model-based blood flow quantification on cerebrovascular data

    NARCIS (Netherlands)

    Groth, A.; Wächter-Stehle, I.; Brina, O.; Perren. F.; Rüfenacht, D.; Bruijns, T.; Bertram, M.; Weese, J.

    2011-01-01

    Diagnosis and treatment decisions of cerebrovascular diseases are currently based on structural information like the endovascular lumen. In future, clinical diagnosis will increasingly be based on functional information which gives direct information about the physiological parameters and, hence, is

  3. 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

  4. 流式细胞仪的临床应用%Clinical Application of Flow Cytometer

    Institute of Scientific and Technical Information of China (English)

    丛玉隆

    2006-01-01

    流式细胞仪(Flow Cytometer)是采用流式细胞技术对细胞或颗粒悬液进行快速分析的自动化分析仪器。流式细胞术(Flow Cytometry,FCM)是上世纪70年代发展起来的一项新技术,它通过对流动液体中排成单列的细胞或颗粒进行逐个分析、测定细胞或颗粒的光散射和荧光情况,以获得其大小、内部结构、DNA、RNA、蛋白质、抗原等物理及化学特征。

  5. 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.

  6. Paradoxical low flow aortic valve stenosis: incidence, evaluation, and clinical significance.

    Science.gov (United States)

    Clavel, Marie-Annick; Pibarot, Philippe; Dumesnil, Jean G

    2014-01-01

    Paradoxical low-flow (PLF) aortic stenosis is defined by a stroke volume index <35 ml/m(2) despite the presence of preserved LV ejection fraction (≥ 50 %). This entity is typically characterized by pronounced LV concentric remodeling with small LV cavity, impaired LV filling, increased arterial load, and reduced LV longitudinal shortening. Patients with PLF also have a worse prognosis compared to patients with normal flow. Because of the low flow state, these patients often have a low gradient despite the presence of severe stenosis, thus leading to discordant AS grading (i.e., aortic valve area < 1.0 cm(2) but mean gradient < 40 mmHg) and thus uncertainty about the indication of aortic valve replacement. Stress echocardiography and aortic valve calcium score by computed tomography may be helpful to differentiate true from pseudo severe stenosis and thereby guide therapeutic management in these patients. Aortic valve replacement improves outcomes in patients with PLF low gradient AS having evidence of severe stenosis. Transcatheter aortic valve replacement may provide an interesting alternative to surgery in these patients.

  7. The basophil activation test by flow cytometry: recent developments in clinical studies, standardization and emerging perspectives

    OpenAIRE

    Debard Anne-Lise; Boumiza Radhia; Monneret Guillaume

    2005-01-01

    Abstract The diagnosis of immediate allergy is mainly based upon an evocative clinical history, positive skin tests (gold standard) and, if available, detection of specific IgE. In some complicated cases, functional in vitro tests are necessary. The general concept of those tests is to mimic in vitro the contact between allergens and circulating basophils. The first approach to basophil functional responses was the histamine release test but this has remained controversial due to insufficient...

  8. 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.

  9. 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.

  10. Ultrasonic characteristics and clinical significance of umbilical cord blood flow in acute fetal distress

    Institute of Scientific and Technical Information of China (English)

    Wei Dai; Yin Xu; Xing-Wei Ma; Li Zhang; Ming-Juan Zhu

    2016-01-01

    Objective: To study ultrasonic characteristics of umbilical cord blood flow in acute fetal distress and its correlation with umbilical artery blood gas parameters, oxidative stress parameters, neonatal brain injury and myocardial injury. Methods: The pregnant women delivered in Department of Obstetrics of our hospital were chosen during the period from May 2012 to August 2015. The pregnant women with acute fetal distress were included in the distress group, and the healthy pregnant women with no acute fetal distress were included in the control group. The resistance index (RI), pulsatility index (PI) and systolic/diastolic (S/D) ratio of umbilical artery were measured at 24–30 weeks, 31–36 weeks and 37–41 weeks of pregnancy. After delivery, umbilical artery blood was taken for analysis of blood gas and determination of oxidative stress parameters. The venous blood of newborns was taken to measure the myocardial injury and brain injury parameters. Results: At 24–30 weeks, 31–36 weeks and 37–41 weeks of pregnancy, RI, S/D and PI in pregnant women of distress group were significantly higher than those in control group. The pH, contents of arterial partial pressure of oxygen, vitamin C, vitamin E, superoxide dis-mutase and glutathione peroxidase in umbilical artery blood in pregnant women of distress group was significantly lower than those in control group and negatively correlated with the umbilical artery RI, PI and S/D. The contents of partial pressure of carbon dioxide in artery, lactic acid and malondialdehyde in pregnant women of distress group were significantly higher than those in control group and positively correlated with the umbilical artery RI, PI and S/D. The contents of lactate dehydrogenase, hydroxybutyrate dehydrogenase, creatine kinase, creatine kinase-MB, S100B, neuron-specific enolase, creatine kinase-BB and Tau in newborns' venous blood in distress group were significantly higher than those in control group and positively correlated

  11. Ultrasonic character istics and clinical significance of umbilical cord blood flow in acute fetal distress

    Directory of Open Access Journals (Sweden)

    Wei Dai, Yin Xu

    2016-11-01

    Full Text Available Objective: To study ultrasonic characteristics of umbilical cord blood flow in acute fetal distress and its correlation with umbilical artery blood gas parameters, oxidative stress parameters, neonatal brain injury and myocardial injury. Methods: The pregnant women delivered in Department of Obstetrics of our hospital were chosen during the period from May 2012 to August 2015. The pregnant women with acute fetal distress were included in the distress group, and the healthy pregnant women with no acute fetal distress were included in the control group. The resistance index (RI, pulsatility index (PI and systolic/diastolic (S/D ratio of umbilical artery were measured at 24–30 weeks, 31–36 weeks and 37–41 weeks of pregnancy. After delivery, umbilical artery blood was taken for analysis of blood gas and determination of oxidative stress parameters. The venous blood of newborns was taken to measure the myocardial injury and brain injury parameters. Results: At 24–30 weeks, 31–36 weeks and 37–41 weeks of pregnancy, RI, S/D and PI in pregnant women of distress group were significantly higher than those in control group. The pH, contents of arterial partial pressure of oxygen, vitamin C, vitamin E, superoxide dismutase and glutathione peroxidase in umbilical artery blood in pregnant women of distress group was significantly lower than those in control group and negatively correlated with the umbilical artery RI, PI and S/D. The contents of partial pressure of carbon dioxide in artery, lactic acid and malondialdehyde in pregnant women of distress group were significantly higher than those in control group and positively correlated with the umbilical artery RI, PI and S/D. The contents of lactate dehydrogenase, hydroxybutyrate dehydrogenase, creatine kinase, creatine kinase-MB, S100B, neuron-specific enolase, creatine kinase-BB and Tau in newborns' venous blood in distress group were significantly higher than those in control group and

  12. 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.

  13. Quantification of coronary flow reserve in patients with ischaemic and non-ischaemic cardiomyopathy and its association with clinical outcomes

    Science.gov (United States)

    Majmudar, Maulik D.; Murthy, Venkatesh L.; Shah, Ravi V.; Kolli, Swathy; Mousavi, Negareh; Foster, Courtney R.; Hainer, Jon; Blankstein, Ron; Dorbala, Sharmila; Sitek, Arkadiusz; Stevenson, Lynne W.; Mehra, Mandeep R.; Di Carli, Marcelo F.

    2015-01-01

    Aims Patients with left ventricular systolic dysfunction frequently show abnormal coronary vascular function, even in the absence of overt coronary artery disease. Moreover, the severity of vascular dysfunction might be related to the aetiology of cardiomyopathy. We sought to determine the incremental value of assessing coronary vascular dysfunction among patients with ischaemic (ICM) and non-ischaemic (NICM) cardiomyopathy at risk for adverse cardiovascular outcomes. Methods and results Coronary flow reserve (CFR, stress/rest myocardial blood flow) was quantified in 510 consecutive patients with rest left ventricular ejection fraction (LVEF) ≤45% referred for rest/stress myocardial perfusion PET imaging. The primary end point was a composite of major adverse cardiovascular events (MACE) including cardiac death, heart failure hospitalization, late revascularization, and aborted sudden cardiac death. Median follow-up was 8.2 months. Cox proportional hazards model was used to adjust for clinical variables. The annualized MACE rate was 26.3%. Patients in the lowest two tertiles of CFR (CFR ≤ 1.65) experienced higher MACE rates than those in the highest tertile (32.6 vs. 15.5% per year, respectively, P = 0.004), irrespective of aetiology of cardiomyopathy. Conclusion Impaired coronary vascular function, as assessed by reduced CFR by PET imaging, is common in patients with both ischaemic and non-ischaemic cardiomyopathy and is associated with MACE. PMID:25719181

  14. 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.

  15. 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.

  16. 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.)

  17. Clinical Outcomes in Patients with Deferred Coronary Lesions according to Disease Severity Assessed by Fractional Flow Reserve.

    Science.gov (United States)

    Won, Ki Bum; Nam, Chang Wook; Cho, Yun Kyeong; Yoon, Hyuck Jun; Park, Hyoung Seob; Kim, Hyungseop; Han, Seongwook; Hur, Seung Ho; Kim, Yoon Nyun; Park, Sang Hyun; Han, Jung Kyu; Koo, Bon Kwon; Kim, Hyo Soo; Doh, Joon Hyung; Lee, Sung Yun; Yang, Hyoung Mo; Lim, Hong Seok; Yoon, Myeong Ho; Tahk, Seung Jea; Kim, Kwon Bae

    2016-12-01

    Data on the clinical outcomes in deferred coronary lesions according to functional severity have been limited. This study evaluated the clinical outcomes of deferred lesions according to fractional flow reserve (FFR) grade using Korean FFR registry data. Among 1,294 patients and 1,628 lesions in Korean FFR registry, 665 patients with 781 deferred lesions were included in this study. All participants were consecutively categorized into 4 groups according to FFR; group 1: ≥ 0.96 (n = 56), group 2: 0.86-0.95 (n = 330), group 3: 0.81-0.85 (n = 170), and group 4: ≤ 0.80 (n = 99). Primary endpoint was major adverse cardiac events (MACE), a composite of all-cause death, myocardial infarction, and target vessel revascularization. The median follow-up period was 2.1 years. During follow-up, the incidence of MACE in groups 1-4 was 1.8%, 7.6%, 8.8%, and 13.1%, respectively. Compared to group 1, the cumulative rate by Kaplan-Meier analysis of MACE was not different for groups 2 and 3. However, group 4 had higher cumulative rate of MACE compared to group 1 (log-rank P = 0.013). In the multivariate Cox hazard models, only FFR (hazard ratio [HR], 0.95; P = 0.005) was independently associated with MACE among all participants. In contrast, previous history of percutaneous coronary intervention (HR, 2.37; P = 0.023) and diagnosis of acute coronary syndrome (ACS) (HR, 2.35; P = 0.015), but not FFR, were independent predictors for MACE in subjects with non-ischemic (FFR ≥ 0.81) deferred coronary lesions. Compared to subjects with ischemic deferred lesions, clinical outcomes in subjects with non-ischemic deferred lesions according to functional severity are favorable. However, longer-term follow-up may be necessary.

  18. Morphologic and Clinical Outcome of Intracranial Aneurysms after Treatment Using Flow Diverter Devices: Mid-Term Follow-Up

    Directory of Open Access Journals (Sweden)

    Anna-Katharina Breu

    2016-01-01

    Full Text Available Flow diverters (FDs are designed for the endovascular treatment of complex intracranial aneurysm configurations. From February 2009 to March 2013 28 patients (22 females, 6 males were treated with FD; mean age was 57 years. Data, including aneurysm features, clinical presentation, history of previous bleeding, treatment, and follow-up results, are presented. Early postinterventional neurological deficits (transient: n=3/enduring: n=1 appeared in 4/28 patients (14%, and early improvement of neurological symptoms was observed in 7 patients with previous restriction of cranial nerve function. The overall occlusion rate was 20/26 (77%; 59% after 3 months. 77% achieved best results according to O’Kelly-Marotta score grade D with no contrast material filling (70% of those after 3 months. In 4/6 patients who did not achieve grade D, proximal and/or distal stent overlapping ≥5 mm was not guaranteed sufficiently. During follow-up we did not detect any aneurysm recurrence or haemorrhage. In-stent stenosis emerged as the most frequent complication (4/27; 15% followed by 2 cases of vascular obliteration (AICA/VA. In conclusion endovascular reconstruction using a FD represents a modern and effective treatment in those aneurysms that are not suitable for conventional interventional or surgical treatment. The appearance of severe complications was rare.

  19. 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.

  20. 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.

  1. 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.

  2. Functionalized Magnetic Resonance Contrast Agent Selectively Binds to Glycoprotein IIb/IIIa on Activated Human Platelets under Flow Conditions and Is Detectable at Clinically Relevant Field Strengths

    Directory of Open Access Journals (Sweden)

    Constantin von zur Mühlen

    2008-03-01

    Full Text Available Recent progress in molecular magnetic resonance imaging (MRI provides the opportunity to image cells and cellular receptors using microparticles of iron oxide (MPIOs. However, imaging targets on vessel walls remains challenging owing to the quantity of contrast agents delivered to areas of interest under shear stress conditions. We evaluated ex vivo binding characteristics of a functional MRI contrast agent to ligand-induced binding sites (LIBSs on activated glycoprotein IIb/IIIa receptors of human platelets, which were lining rupture-prone atherosclerotic plaques and could therefore facilitate detection of platelet-mediated pathology in atherothrombotic disease. MPIOs were conjugated to anti-LIBS single-chain antibodies (LIBS-MPIO or control antibodies (control MPIO. Ex vivo binding to human platelet-rich clots in a dose-dependent manner was confirmed on a 3 T clinical MRI scanner and by histology (p < .05 for LIBS-MPIO vs control MPIO. By using a flow chamber setup, significant binding of LIBS-MPIO to a platelet matrix was observed under venous and arterial flow conditions, but not for control MPIO (p < .001. A newly generated MRI contrast agent detects activated human platelets at clinically relevant magnetic field strengths and binds to platelets under venous and arterial flow conditions, conveying high payloads of contrast to specific molecular targets. This may provide the opportunity to identify vulnerable, rupture-prone atherosclerotic plaques via noninvasive MRI.

  3. Establishment of a reference interval for natural killer cell activity through flow cytometry and its clinical application in the diagnosis of hemophagocytic lymphohistiocytosis.

    Science.gov (United States)

    Chung, H J; Park, C J; Lim, J H; Jang, S; Chi, H S; Im, H J; Seo, J J

    2010-04-01

    Recently, the Histiocyte Society revised the diagnostic criteria for hemophagocytic lymphohistiocytosis (HLH) to include low or absent natural killer (NK) cell activity, according to local laboratory reference. The aim of this study was to establish reference interval for functional NK-cell activity in 63 healthy Korean individuals using a flow-cytometric assay. We used peripheral blood mononuclear cells (PBMCs) as effector cells and Fluorescein isothiocyanate-labeled K562 cells as target cells. NK-cell activity was calculated using the following equation: NK-cell activity (%) = (test lysis - spontaneous lysis) x 100/(maximum lysis - spontaneous lysis). NK-cell activity was analyzed in 13 known HLH patients and 16 suspected non-HLH patients using a flow-cytometric assay. The mean (+/-SD) cytotoxicity of PBMCs from healthy individuals was 20.9 +/- 5.3% and the reference interval was 11.8-31.9%. The mean NK-cell activity of HLH patients (8.3 +/- 8.9%) was significantly lower (P = 0.001) than that of non-HLH patients (20.1 +/- 7.8%). The sequential changes in NK-cell activity in the HLH group corresponded to clinical and laboratory findings following treatment. We successfully developed a functional NK-cell activity test for use in the clinical laboratory and obtained a reference interval of NK-cell activity from healthy donors. This assay, and associated reference interval, was used to analyze 30 clinically relevant specimens and the results were shown to be well correlated.

  4. 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 < 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.

  5. 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.

  6. 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, ...

  7. 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

  8. 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...

  9. Flow cytometer and the clinical application%流式细胞仪及其临床应用

    Institute of Scientific and Technical Information of China (English)

    丛玉隆

    2006-01-01

    @@ 流式细胞仪(Flow Cytometer)是采用流式细胞技术对细胞或颗粒悬液进行快速分析的自动化分析仪器.流式细胞术(Flow Cytometry,简称FCM)是上世纪70年代发展起来的一项新技术,它通过对流动液体中排成单列的细胞或颗粒进行逐个分析、测定细胞或颗粒的光散射和荧光情况,以获得其大小、内部结构、DNA、RNA、蛋白质、抗原等物理及化学特征.

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

    OpenAIRE

    2009-01-01

    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 neuropa...

  11. 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

  12. 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

  13. Clinical outcomes of combined flow-pressure drop measurements using newly developed diagnostic endpoint:Pressure drop coefficient in patients with coronary artery dysfunction

    Institute of Scientific and Technical Information of China (English)

    Mohamed A Effat; Srikara Viswanath Peelukhana; Rupak K Banerjee

    2016-01-01

    AIM:To combine pressure and flow parameter, pressure drop coefficient(CDP) will result in better clinical outcomes in comparison to the fractional flow reserve(FFR) group. METHODS:To test this hypothesis, a comparison was made between the FFR 27.9 groups in this study, for the major adverse cardiac events [major adverse cardiac events(MACE): Primary outcome] and patients’ quality of life(secondary outcome). Further, a comparison was also made between the survival curves for the FFR 27.9 groups. Two-tailed χ~2 test proportions were performed for the comparison of primary and secondary outcomes. Kaplan-Meier survival analysis was performed to compare the survival curves of FFR 27.9 groups(MedcalcV10.2, Mariakerke, Belgium). Results were considered statistically significant for P 27.9 group(8.57%, 2 out of 35). Noteworthy is the reduction in the %MACE in the CDP > 27.9 group, in comparison to the FFR 27.9 groups. Survival analysis results suggest that the survival time for the CDP > 27.9 group(n = 35) is significantly higher(P = 0.048) in comparison to the survival time for the FFR < 0.75 group(n = 20). The results remained similar for a FFR = 0.80 cut-off. CONCLUSION: Based on the above, CDP could prove to be a better diagnostic end-point for clinical revascularization decision-making in the cardiac catheterization laboratories.

  14. Rapid detection of herpes simplex virus in clinical samples by flow cytometry after amplification in tissue culture.

    OpenAIRE

    McSharry, J J; Costantino, R; McSharry, M B; Venezia, R A; Lehman, J M

    1990-01-01

    Murine monoclonal antibodies (MAbs) against herpes simplex virus type 1 and 2 (HSV-1 and -2, respectively) nuclear antigens were used to identify cells infected with HSV-1 or -2 by indirect immunofluorescence in conjunction with flow cytometry after virus amplification of MRC-5 cell monolayers. The results indicate that MAbs Q1, Q2, and H-640 detect HSV-1- and HSV-2-infected cells, MAb SD-1 detects HSV-2- but not HSV-1-infected cells, and MAb 58-S detects HSV-1- but not HSV-2-infected cells. ...

  15. 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.

  16. Clinical relevance of anti-HLA antibodies detected by flow-cytometry bead-based assays--single-center experience.

    Science.gov (United States)

    Mihaylova, Anastassia; Baltadjieva, Daniela; Boneva, Petia; Ivanova, Milena; Penkova, Kalina; Marinova, Daniela; Mihailova, Snejina; Paskalev, Emil; Simeonov, Petar; Naumova, Elissaveta

    2006-10-01

    The purpose of this study was to define the incidence, dynamics, and profiles of anti-human leukocyte antigen antibodies (HLA-Abs) produced after kidney transplantation and their impact on graft outcome. A total of 72 first cadaver donor kidney recipients were prospectively monitored for the development of HLA-Abs using bead-based flow-cytometry assays (One Lambda FlowPRA tests). Sixteen recipients (22.2%) developed HLA-Abs after transplantation (class I, n = 7; class I+II, n = 6; class II, n = 3), in most cases (81.25%) within the first 2 weeks posttransplantation. A strong association between alloantibody presence and delayed graft function (Chi-square = 7.659, p < 0.01), acute rejection (Chi-square = 14.504, p < 0.001), chronic rejection (Chi-square = 12.84, p < 0.001), and graft loss (Chi-square = 20.283, p < 0.001) was found. Patients with higher alloantibody titers experienced acute rejections and even early graft loss, compared with those with lower titers for whom chronic rejections were more common. Immunologic complications occurred in recipients with both donor-specific and cross-reacting groups or non-donor-specific antibodies alone. A positive correlation (Pearson correlation, 0.245; p < 0.05) between HLA class I amino acid triplet incompatibility and alloantibody production was observed, mainly resulting from immunogenic triplotypes. Given the results obtained in this study, an alloantibody testing algorithm has been designed and implemented for routine monitoring and to define optimally the alloantibody reactivity in kidney transplant recipients.

  17. 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.

  18. [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.

  19. 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.

  20. 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.

  1. Um fotômetro de fluxo para análises clínicas a base de um diodo emissor de luz bicolor An inexpensive flow photometer for clinical analysis based on a bicolour light emitting diode

    Directory of Open Access Journals (Sweden)

    M. C. U. Araújo

    1997-04-01

    Full Text Available The construction and evaluation of an inexpensive flow photometer for clinical analysis, using a bicolour LED and a phototransistor adapted for tubular flow cell, are described. The instrument presents some new features such as: automatic zero, electronic calibration and peak-hold signal. When compared with a classical photometer, it is simpler and has the advantages of a flow analysis system: lower volumes of reagents and samples, lower levels of contamination, shorter time for analysis and lower analysis costs. The instrument was used in the determination of the constituents in blood samples. The results obtained agree with those obtained by a classical photometer and the precision was better.

  2. Preserved Collateral Blood Flow in the Endovascular M2CAO Model Allows for Clinically Relevant Profiling of Injury Progression in Acute Ischemic Stroke

    Science.gov (United States)

    Little, Philip; Kvist, Ola; Grankvist, Rikard; Jonsson, Stefan; Damberg, Peter; Söderman, Michael; Arnberg, Fabian; Holmin, Staffan

    2017-01-01

    Interventional treatment regimens have increased the demand for accurate understanding of the progression of injury in acute ischemic stroke. However, conventional animal models severely inhibit collateral blood flow and mimic the malignant infarction profile not suitable for treatment. The aim of this study was to provide a clinically relevant profile of the emergence and course of ischemic injury in cases suitable for acute intervention, and was achieved by employing a M2 occlusion model (M2CAO) that more accurately simulates middle cerebral artery (MCA) occlusion in humans. Twenty-five Sprague-Dawley rats were subjected to Short (90 min), Intermediate (180 min) or Extended (600 min) transient M2CAO and examined longitudinally with interleaved diffusion-, T2- and arterial spin labeling perfusion-weighted magnetic resonance imaging before and after reperfusion. We identified a rapid emergence of cytotoxic edema within tissue regions undergoing infarction, progressing in several distinct phases in the form of subsequent moderation and then reversal at 230 min (p < 0.0001). We identified also the early emergence of vasogenic edema, which increased consistently before and after reperfusion (p < 0.0001). The perfusion of the penumbra correlated more strongly to the perfusion of adjacent tissue regions than did the perfusion of regions undergoing infarction (p = 0.0088). This was interpreted as an effect of preserved collateral blood flow during M2CAO. Accordingly, we observed only limited recruitment of penumbra regions to the infarction core. However, a gradual increase in infarction size was still occurring as late as 10 hours after M2CAO. Our results indicate that patients suffering MCA branch occlusion stand to benefit from interventional therapy for an extended time period after the emergence of ischemic injury. PMID:28068417

  3. 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.

  4. Monitoring regulatory T cells in clinical samples: consensus on an essential marker set and gating strategy for regulatory T cell analysis by flow cytometry.

    Science.gov (United States)

    Santegoets, Saskia J A M; Dijkgraaf, Eveline M; Battaglia, Alessandra; Beckhove, Philipp; Britten, Cedrik M; Gallimore, Awen; Godkin, Andrew; Gouttefangeas, Cecile; de Gruijl, Tanja D; Koenen, Hans J P M; Scheffold, Alexander; Shevach, Ethan M; Staats, Janet; Taskén, Kjetil; Whiteside, Theresa L; Kroep, Judith R; Welters, Marij J P; van der Burg, Sjoerd H

    2015-10-01

    Regulatory T cell (Treg)-mediated immunosuppression is considered a major obstacle for successful cancer immunotherapy. The association between clinical outcome and Tregs is being studied extensively in clinical trials, but unfortunately, no consensus has been reached about (a) the markers and (b) the gating strategy required to define human Tregs in this context, making it difficult to draw final conclusions. Therefore, we have organized an international workshop on the detection and functional testing of Tregs with leading experts in the field, and 40 participants discussing different analyses and the importance of different markers and context in which Tregs were analyzed. This resulted in a rationally composed ranking list of "Treg markers". Subsequently, the proposed Treg markers were tested to get insight into the overlap/differences between the most frequently used Treg definitions and their utility for Treg detection in various human tissues. Here, we conclude that the CD3, CD4, CD25, CD127, and FoxP3 markers are the minimally required markers to define human Treg cells. Staining for Ki67 and CD45RA showed to provide additional information on the activation status of Tregs. The use of markers was validated in a series of PBMC from healthy donors and cancer patients, as well as in tumor-draining lymph nodes and freshly isolated tumors. In conclusion, we propose an essential marker set comprising antibodies to CD3, CD4, CD25, CD127, Foxp3, Ki67, and CD45RA and a corresponding robust gating strategy for the context-dependent analysis of Tregs by flow cytometry.

  5. Development and laboratory validation of a lateral flow device for the detection of serotype SAT 2 foot-and-mouth disease viruses in clinical samples.

    Science.gov (United States)

    Ferris, Nigel P; Nordengrahn, Ann; Hutchings, Geoffrey H; Paton, David J; Kristersson, Therese; Brocchi, Emiliana; Grazioli, Santina; Merza, Malik

    2010-02-01

    A lateral flow device (LFD) for the detection of foot-and-mouth disease virus (FMDV) of the SAT 2 serotype was developed using a monoclonal antibody (Mab 2H6). The performance of the LFD was evaluated in the laboratory on suspensions of vesicular epithelia: 305 positive for FMDV type SAT 2 from suspected cases of vesicular disease collected from 30 countries and 1002 samples shown to be negative for FMDV type SAT 2 collected from 67 countries between 1968 and 2008. The diagnostic sensitivity of the LFD for FMDV type SAT 2 was higher at 88% compared to 79% obtained by the reference method of antigen ELISA, and the diagnostic specificity of the LFD was approximately 99% compared to 100% for the ELISA. The device recognized FMDV strains of wide diversity within the FMDV SAT 2 serotype and gave a superior performance for their detection compared to the 1F10 LFD which had been developed previously and shown to perform less well for the detection of FMDVs of this particular serotype. Reactions in the SAT 2 2H6 LFD with the viruses of other FMDV serotypes and swine vesicular disease (which produces a clinically indistinguishable syndrome in pigs), did not occur. These data illustrate the potential for the LFD to be employed to complement the 1F10 device next to the animal in the pen-side diagnosis of FMD, for providing rapid and objective support to veterinarians in their clinical judgment of the disease and for specific confirmation of a FMDV type SAT 2 infection.

  6. Rapid identification of ascomycetous yeasts from clinical specimens by a molecular method based on flow cytometry and comparison with identifications from phenotypic assays.

    Science.gov (United States)

    Page, Brent T; Shields, Christine E; Merz, William G; Kurtzman, Cletus P

    2006-09-01

    This study was designed to compare the identification of ascomycetous yeasts recovered from clinical specimens by using phenotypic assays (PA) and a molecular flow cytometric (FC) method. Large-subunit rRNA domains 1 and 2 (D1/D2) gene sequence analysis was also performed and served as the reference for correct strain identification. A panel of 88 clinical isolates was tested that included representatives of nine commonly encountered species and six infrequently encountered species. The PA included germ tube production, fermentation of seven carbohydrates, morphology on corn meal agar, urease and phenoloxidase activities, and carbohydrate assimilation tests when needed. The FC method (Luminex) employed species-specific oligonucleotides attached to polystyrene beads, which were hybridized with D1/D2 amplicons from the unidentified isolates. The PA identified 81 of 88 strains correctly but misidentified 4 of Candida dubliniensis, 1 of C. bovina, 1 of C. palmioleophila, and 1 of C. bracarensis. The FC method correctly identified 79 of 88 strains and did not misidentify any isolate but did not identify nine isolates because oligonucleotide probes were not available in the current library. The FC assay takes approximately 5 h, whereas the PA takes from 2 h to 5 days for identification. In conclusion, PA did well with the commonly encountered species, was not accurate for uncommon species, and takes significantly longer than the FC method. These data strongly support the potential of FC technology for rapid and accurate identification of medically important yeasts. With the introduction of new antifungals, rapid, accurate identification of pathogenic yeasts is more important than ever for guiding antifungal chemotherapy.

  7. 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.

  8. 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.

  9. Uterine fibroid embolization with spheric micro-particles using flow guiding: safety, technical success and clinical results; Uterusmyomembolisation mit sphaerischen Mikropartikeln unter Flusssteuerung: Sicherheit, technischer Erfolg und klinische Ergebnisse

    Energy Technology Data Exchange (ETDEWEB)

    Richter, G.M.; Radeleff, B.; Kauffmann, G.W. [Ruprecht-Karls-Univ. Heidelberg, Abt. fuer Radiodiagnostik, Radiologische Universitaetsklinik (Germany); Rimbach, S. [Ruprecht-Karls-Univ. Heidelberg, Univ.-Frauenklinik (Germany); RWTH Aachen, Univ.-Frauenklinik (Germany)

    2004-11-01

    Materials and Methods: Twenty of the first 26 consecutive patients referred for potential UFE were enrolled in the study. Pre-interventional MRI was used to assess morphologic contraindication to UFE. The embolization procedures were performed from a unilateral femoral approach using 4F selective catheters in straight vessels, >2 mm in diameter, and micro-catheters in smaller and tortuous arteries. The endpoint of the 'flow guided' embolization was defined by reaching the angiography 'pruned tree' appearance and sluggish flow in the main stem of the uterine artery. Assessment of morphologic mid term success was done by MRI 10 days, 3 months, 6 months, 9 months and 1 year after UFE. The clinical mid term success was assessed by having questionaires completed for menstrual bleeding, retention of clinical (symptomatic) benefit and quality of life. Results: Technical success was 100%, with 8 minor (2 post-interventional collapses, 2 hematomas, 4 relevant post-embolizations syndromes, 1 spontaneous expulsion of a submucous myoma) and 3 major complications (1 hysterectomy because of vaginal bleeding for 5 weeks, 1 transient amenorrhea and 1 spontaneous expulsion of myoma with transient bleeding requiring admission). In 17 of 19 patients, MRI showed total fibroid devascularization throughout the entire follow-up. The average shrinkage of the dominant fibroid was 71.3% at one year. The menstrual bleeding record in the cohort group fell from an average of 501.6 before treatment to 76.2 points at one year. At the same time, the clinical symptoms significantly improved. The patient satisfaction with the applied therapy was >95% at 1 year. One patient with residual fibroid perfusion underwent a second procedure, which achieved complete devascularization and adequate clinical success at one year. The second patient with incomplete devascularization had a persistent clinical benefit. (orig.)

  10. 流式细胞仪工作原理与临床应用%The Principle of Flow Cytometer and Clinical Application

    Institute of Scientific and Technical Information of China (English)

    李华; 常莹

    2011-01-01

    流式细胞术( flow cytometry,FCM)为当代最先进的细胞定量分析技术,目前普遍应用于临床医学检测和基础医学研究领域.本文阐述了流式细胞仪的结构和原理,总结了其在临床医学领域中诸多方面的应用.

  11. [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.

  12. Visualising patient flow.

    Science.gov (United States)

    Jensen, Andrew; Boyle, Justin; Khanna, Sankalp

    2012-01-01

    We describe the development of a method to distil routinely collected clinical data into patient flow information to aid hospital bed management. Using data from state-wide emergency department and inpatient clinical information systems, a user-friendly interface was developed to visualise patient flow conditions for a particular hospital. The historical snapshots employ a variable time scale, allowing flow to be visualised across a day, week, month or year. Flow information includes occupancy, arrival and departure rates, length-of-stay and access block observations, which can be filtered by age, departure status, diagnosis, elective status, triage category, and admission unit. The tool may be helpful in supporting hospital bed managers in their daily decision making.

  13. 影响胎儿大脑中动脉血流峰速的临床相关因素%Related clinical effect factors of peak velocity of blood flow of fetal middle cerebral artery

    Institute of Scientific and Technical Information of China (English)

    凌奕; 金松; 南瑞霞; 华少萍; 张宏玉; 胡春霞; 莫秀兰

    2011-01-01

    Objective: To analyze the related clinical effect factors of peak velocity of blood flow of fetal middle cerebral artery ( MCA) , provide a basis for predicting fetal anemia by peak velocity of blood flow of MCA. Methods; 140 fetuses from the hospital were analyzed and divided into normal control group (85 fetuses), uncomplicated twin group (22 fetuses) , thalassemia group (IS fetuses) and fetal anomaly group (18 fetuses) , all the fetuses received color Doppler examination of peak velocity of blood flow of MCA and hemoglobin detection. MOM value was used as the unit, the differences of peak velocities of blood flow of MCA and fetal hemoglobin contents among the four groups were analyzed. Results; There was no significant difference in peak velocity of blood flow of MCA and fetal hemoglobin content between uncomplicated twin group and single pregnancy group. In thalassemia group, the peak velocity of blood flow of MCA increased significantly , while fetal hemoglobin content decreased. Compared with normal single pregnancy group, the peak velocity of blood flow of MCA in fetal anomaly group increased significantly (P < 0. 05 ) , but after exclusing anemia fetuses, there is no significant difference in the peak velocity of blood flow of MCA between fetal anomaly non - anemia group and normal single pregnancy group. Conclusion: The peak velocity of blood flow of MCA is significantly related to fetal anemia, but there was no correlation between peak velocity of blood now of MCA and un-complicated twin pregnancy; the study shows that there is no significant difference in the peak velocity of blood flow of MCAbetween fetal anomaly non - anemia group and normal single pregnancy group after exclusing anemia fetuses, a further study with large samples is needed.%目的:分析影响胎儿大脑中动脉血流峰速(MCA-PSV)的临床相关因素,为应用MCA-PSV预测胎儿贫血提供依据.方法:对海南医学院附属医院140例胎儿进行临

  14. Uses of clinical algorithms.

    Science.gov (United States)

    Margolis, C Z

    1983-02-04

    The clinical algorithm (flow chart) is a text format that is specially suited for representing a sequence of clinical decisions, for teaching clinical decision making, and for guiding patient care. A representative clinical algorithm is described in detail; five steps for writing an algorithm and seven steps for writing a set of algorithms are outlined. Five clinical education and patient care uses of algorithms are then discussed, including a map for teaching clinical decision making and protocol charts for guiding step-by-step care of specific problems. Clinical algorithms are compared as to their clinical usefulness with decision analysis. Three objections to clinical algorithms are answered, including the one that they restrict thinking. It is concluded that methods should be sought for writing clinical algorithms that represent expert consensus. A clinical algorithm could then be written for any area of medical decision making that can be standardized. Medical practice could then be taught more effectively, monitored accurately, and understood better.

  15. 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.

  16. 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

  17. 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

  18. 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

  19. El flujómetro de Wright: Una herramienta indispensable en la práctica ambulatoria Wright portable Peak Flow-meter: A "must" in out-patient clinic

    Directory of Open Access Journals (Sweden)

    Ricardo Sepúlveda M

    2004-04-01

    Full Text Available La evaluación de la Función Respiratoria (FR a pesar de su demostrada utilidad diagnóstica, pronóstica y de evaluación de la eficacia terapéutica, no ha sido incorporada en forma habitual a la práctica clínica ambulatoria, como lo ha sido el ECG, la glicemia, el esfingomanómetro e incluso la radiografía de tórax. La falta de accesibilidad al equipamiento necesario ha sido una de sus justificaciones. Hace más de 20 años que se dispone de un sencillo equipo portátil, de bajo costo que puede medir los flujos espiratorios máximos denominado flujómetro y que en variadas versiones ha venido a colaborar en la objetivación del componente obstructivo de las enfermedades respiratorias en la consulta ambulatoria, e incluso en el domicilio o trabajo del paciente. Esta evaluación parcial de la FR, viene a cubrir al grupo mayoritario de pacientes respiratorios crónicos, y a pesar de sus limitaciones asociadas a la necesaria cooperación para su ejecución, su fácil repetición en el tiempo y en diversas condiciones, le confiere un valor inapreciable en la práctica médica diaria. Los asmáticos, tanto durante sus exacerbaciones como en los controles periódicos, son el grupo que lo requiere en forma imprescindible si se quieren cumplir los objetivos terapéuticos acordados internacionalmente como normas mínimas de calidadIn spite of the general agreement of proven utility of pulmonary function evaluation in helping health care professionals to make right decisions with respiratory patients in specific clinical circumstances, the daily life activity does not include these measurements. This approach differs with the regular use of ECG, glucose, cholesterol, arterial blood pressure measurement or even chest X ray. Spirometer limited availability in out-patient setting was the most common argument to back this attitude. For more than 20 years a very economic, reliable and portable equipment to measure the peak expiratory flows, is available

  20. Clinical studies on the distribution of the pulmonary blood flow at rest and with exercise in mitral stenosis in connection with the reversibility of the pulmonary vascular lesion

    Energy Technology Data Exchange (ETDEWEB)

    Kohno, Tomio

    1988-09-01

    In order to determine the severity and reversibilty of pathologic changes in the pulmonary vascular bed in mitral stenosis (MS), a retrospective review was made of pulmonary perfusion scans obtained at rest and during exercise in a series of 60 subjects - 37 patients with MS, 8 with mitral regurgitation (MR), 7 with aortic regurgitation and stenosis (ARS), and 8 normal persons (N). As expressed by Q(U/L), an increased ratio of pulmonary blood flow in the upper part to that in the lower part of the lung was significantly associated with exercise in the MR and ARS groups, as well as the N group. In the MS group, Q(U/L) patterns associated with exercise fell into three categories: (I) an increase in Q(U/L) that was lower at rest than 1.1, (II) an increase in Q(U/L) that was higher at rest that 1.1, and (III) a decrease in Q(U/L). The MS group I had the worst preoperative parameters for cardiac and pulmonary function, followed by the group II and then the group III. For 23 patients receiving mitral valve replacement, postoperative parameters, including mean pulmonary arterial pressure, cardiac index, and pulmonary arterial resistance, were worse in the group II than the groups I and III. The results suggest that organic changes in the pulmonary vascular bed, as opposed to its reversible changes in the groups I and III, have occurred in the group II. Q(U/L) changes associated with exercise may be of value in determining the severity of MS. (Namekawa, K.).

  1. Clinical studies of cerebral circulation using single photon emission computed tomography, 2; Evaluation of cerebral blood flow after acetazolamide loading on moyamoya disease

    Energy Technology Data Exchange (ETDEWEB)

    Uno, Toshiro [Gifu Univ. (Japan). Faculty of Medicine

    1993-09-01

    To evaluate cerebral blood flow (CBF) in patients with moyamoya disease, single photon emission computed tomography (SPECT) was performed using acetazolamide-activated {sup 133}Xe inhalation method. In the present investigation, 15 patients were subjected: 6 pediatric cases with the mean age of 10.8 years and 9 adult cases with the mean age of 44.6 years. The regional CBF (rCBF) was measured in the territory of anterior cerebral artery (ACA), middle cerebral artery (MCA), posterior cerebral artery (PCA), basal ganglia, and cerebellum. Cerebrovascular acetazolamide reactivity was evaluated from the rCBF measured before and after administration of acetazolamide. Namely, cerebrovascular acetazolamide reactivity was expressed as %CBF and calculated as follows: %CBF=100 x (CBF after acetazolamide administration-CBF at rest)/CBF at rest. rCBF in adult patients was decreased in the cerebral hemisphere, while that in childhood was significantly decreased in the territory of ACA. The %CBF after acetazolamide loading was decreased in the territory of ACA and MCA in both adult and childhood. When cerebral %CBF was compared to the cerebellar %CBF, the ratio of cerebral %CBF and cerebellar %CBF resulted in markedly lower in childhood than adult. rCBF and cerebrovascular acetazolamide reactivity were also measured before and after extracranial and intracranial (EC-IC) bypass surgery in three pediatric moyamoya patients. Although rCBF was increased immediately after EC-IC bypass surgery, the cerebrovascular acetazolamide reactivity remained blunted. These results meant that in the pediatric moyamoya patients cerebrovascular acetazolamide reactivity is more blunted than adult moyamoya patients. Also, the cerebral vessels in moyamoya disease were considered to be dilated to their limitation by the blood supplied through the EC-IC bypass and not to be expandable any more by acetazolamide. (author) 45 refs.

  2. Clinical risk factor analysis of slow coronary flow phenomenon%冠状动脉慢血流现象的临床影响因素分析

    Institute of Scientific and Technical Information of China (English)

    陈晖

    2015-01-01

    Objective To explore the risk factor of slow coronary flow (SCF) phenomenon. Methods 200 cases without obvious pathological changes of epicardial coronary artery by coronary angiography from January 2011 to June 2013 in our hospital were selected as the research object,the adjusted TIMI frame was more than 2 standard deviation of normal coronary flow velocity were defined as SCF.The comparison of age,gender,smoking history,body mass index(BMI),comor-bidities(including hypertension,diabetes,and hyperlipidemia),the level of and serum uric acid,C-reactive protein,platelet aggregation were analysed between the SCF group and the coronary artery normal group.The risk factor of SCF was analysed and observed by multiple regression analysis. Results BMI,the proportion of smoking history in the SCF group was higher than that in the coronary artery normal group,with significant difference (P<0.05).The level of serum uric acid,homocysteine,C reactive protein and platelet aggregation rate in the SCF group was higher than that in the normal group,with significant difference(P<0.05).Multivariate regression analysis showed that age,smoking,hyperlipidemia,serum uric acid,homocysteine,C reactive protein,platelet aggregation rate were the risk factors of SCF. Conclusion Age,smok-ing,high fat metabolism and inflammation status and high platelet aggregation are all risk factors of SCF phenomenon.%目的:探讨冠状动脉慢血流现象的相关影响因素。方法选取本院2011年1月~2013年6月冠状动脉造影显示心外膜主要冠状动脉无明显病变的200例患者作为研究对象,将校正的TIMI帧数大于正常冠状动脉血流速度2个标准差者定义为冠状动脉慢血流,分析冠状动脉慢血流组和冠状动脉正常组的年龄、性别、吸烟史、体重指数(BMI)、合并症(包括高血压、糖尿病和高脂血症)、以及血尿酸水平、同型半胱氨酸浓度、C反应蛋白水平、血小板聚集率等的差异,同时

  3. 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.

  4. Flow Control

    Science.gov (United States)

    2013-04-08

    an aerodynamic design. A few examples of this type of flow control are winglets , fins, or dimples on a golf ball. The other type of flow control is...represented the density states of the flow field. The first parameter was the composition of the regression vector, Θ j. This regression vector was...Development Using Proper Orthogonal De- composition and Volterra Theory. In AIAA 2003-1922, 2003. A. Mani, M. Wang, and P. Moin. Resolution requirements

  5. 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

  6. Clinical Study of Sevoflurane and Isoflurane in Low Flow Anesthesia%七氟醚和异氟醚低流量吸入麻醉的临床应用

    Institute of Scientific and Technical Information of China (English)

    陈龙谦; 黄慧瑜; 黄丽

    2014-01-01

    Objective To investigate the clinical effect of sevoflurane and isoflurane on patients with low flow anesthesia. Meth-ods Among the patients needing operation treatment with endotracheal intubation and general anesthesia in our hospital, 90 patients were selected and randomly divided into the experimental group and the control group, 45 patients in each group. The two groups a-dopted the same anesthesia technology-low flow anesthesia. Based on this, the test group received Sevoflurane anesthesia, while the control group received Isoflurane anesthesia. The two anesthetics' clinical effects were compared based on the observation of the awak-ening time, extubation time, aldrete grade time and the satisfaction degree of patients between the two groups. Results There was no statistical difference in gender, age, weight, height, operation time and other basic information between the two groups. Through the observation and statistics, the recovery time, extubation time and Aldrete score time in experimental group were shorter than those in the control group. There was statistically significant difference between the two groups (P< 0.05). In the postoperative satisfaction survey, the experimental group (43 cases, accounting for 95.6% of the total) was significantly higher than the control group (30 ca-ses, accounting for 66.7% of the total). The difference was obvious with statistical significance (P< 0.05). Conclusion Low flow anesthesia with Sevoflurane has good security, effects and high satisfaction degree compared with Isoflurane, which can be widely used in clinical practice.%目的探讨临床上采用七氟醚和异氟醚低流量麻醉时对患者疗效的对比。方法在我院收治的手术治疗时需要气管插管和全身麻醉的患者中,抽取90例随机分成试验组和对照组,试验组和对照组各45名患者。在接收相同的低流量麻醉技术麻醉前提下,试验组接收七氟醚麻醉,对照组接受异氟醚麻醉。通过观

  7. Network Flows

    Science.gov (United States)

    1988-12-01

    Researchers have suggested other solution strategies, using ideas from nonlinear progamming for solving this general separable convex cost flow problems. Some...plane methods and branch and bound procedures of integer programming, primal-dual methods of linear and nonlinear programming, and polyhedral methods...Combinatorial Optimization: Networks and Matroids), Bazaraa and Jarvis [1978] (Linear Programming and Network Flows), Minieka [1978] (Optimization Algorithms for

  8. 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...

  9. 不同流式细胞分析仪检测淋巴细胞亚群的比较研究%Comparison of three different flow cytometers in the clinical assessment of lymphocyte subsets

    Institute of Scientific and Technical Information of China (English)

    王维维; 奚迪; 袁向亮; 沈立松

    2016-01-01

    Objective To evaluate the consistency and accuracy among 3 brands of flow cytometers (BriCyte E6,BD FACSCanto Ⅱ and Beckman Coulter FC 500) in the detection of lymphocyte subsets.Methods According to the methodology,the BriCyte E6 was compared with 2 flow cytometers commonly used in clinical detection.Seventy-three cases (40 male and 33 female) of anticoagulation peripheral blood specimens were collected in the clinical laborartory department of Xinhua Hospital in July 2015 and the percentage (%) and absolute number (#) of the lymphocyte subsets were detected by 3 different flow cytometers within samples collected 4 h.Results There were good consistency among the 3 flow cytometers (R2 >0.95,R2 from 0.969 5 to 0.992 4) in the detection of lymphocyte subsets percentage,so did in the detection of absolute number (R2 > 0.95,R2 from 0.969 1 to 0.993 3).As to the precision evaluation,in the detectionof CD8%,T#,CD4+ T# and CD8+ T#,BriCyte E6 achieved a low CV% compared with FACSCanto Ⅱ and FC 500 (Friedman statistics are 16.720,11.840,15.760 and 15.430,P =0.000 2,0.027,0.000 4,0.000 4,respectively).In the detection of T%,CD4%,NK%,B%,NK#,B#,there was no significant difference among the 3 flow cytometers (Friedman statistics are 4.242,3.916,0.852,2.595,1.835 and 0.578,P =0.119 9,0.141 2,0.653 2,0.273 3,0.399 6,0.749 0,respectively).Conclusions The 3 flow cytometers have a good consistency in the detection of lymphocyte subsets.BriCyte E6 may be an alternative or complement of existing flow cytometers.%目的 通过对淋巴细胞亚群百分比及绝对计数的检测,对比3种流式细胞仪(BriCyteE6、BD FACSCanto Ⅱ、Beckman Coulter FC 500)在淋巴细胞亚群检测中的一致性和精密度.方法 按照方法学对比的要求,将BriCyte E6与2种临床常用的流式细胞仪进行比对.2015年7月连续5d随机收集上海交通大学医学院附属新华医院检验科抽取的新鲜肝素抗凝外周全血标本73

  10. Automated and sensitive determination of four anabolic androgenic steroids in urine by online turbulent flow solid-phase extraction coupled with liquid chromatography-tandem mass spectrometry: a novel approach for clinical monitoring and doping control.

    Science.gov (United States)

    Guo, Feng; Shao, Jing; Liu, Qian; Shi, Jian-Bo; Jiang, Gui-Bin

    2014-07-01

    A novel method for automated and sensitive analysis of testosterone, androstenedione, methyltestosterone and methenolone in urine samples by online turbulent flow solid-phase extraction coupled with high performance liquid chromatography-tandem mass spectrometry was developed. The optimization and validation of the method were discussed in detail. The Turboflow C18-P SPE column showed the best extraction efficiency for all the analytes. Nanogram per liter (ng/L) level of AAS could be determined directly and the limits of quantification (LOQs) were 0.01 ng/mL, which were much lower than normally concerned concentrations for these typical anabolic androgenic steroids (AAS) (0.1 ng/mL). The linearity range was from the LOQ to 100 ng/mL for each compound, with the coefficients of determination (r(2)) ranging from 0.9990 to 0.9999. The intraday and interday relative standard deviations (RSDs) ranged from 1.1% to 14.5% (n=5). The proposed method was successfully applied to the analysis of urine samples collected from 24 male athletes and 15 patients of prostate cancer. The proposed method provides an alternative practical way to rapidly determine AAS in urine samples, especially for clinical monitoring and doping control.

  11. 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.

  12. 低流量七氟醚用于腹腔镜手术麻醉的临床疗效%Clinical curative effect of low flow sevoflurane in treatment of laparoscopic operation anesthesia

    Institute of Scientific and Technical Information of China (English)

    房兰天; 王超; 孟瑞霞

    2016-01-01

    目的:探讨低流量七氟醚用于腹腔镜手术麻醉的临床疗效。方法选择2014年5月~2015年5月我院收治的110例腹腔镜手术病例作为研究对象,根据双盲法将其平均分为研究组与对照组,各55例。对照组采取雷米芬太尼麻醉维持,研究组应用低流量七氟醚麻醉维持。结果对照组气腹前、气腹10min及麻醉苏醒时收缩压、舒张压及心率均低于研究组,差异有统计学意义(P<0.05)。研究组患者的拔管时间(5.8±2.2)min、清醒时间(8.2±3.2)min均低于对照组的拔管时间(10.4±4.5)min、清醒时间(14.8±2.4)min,差异有统计学意义(P<0.05)。结论低流量七氟醚在腹腔镜手术麻醉中具有显著的应用效果,可以有效缩短拔管时间、清醒时间,保证血流动力学稳定性,适于临床应用。%Objective To explore the clinical curative effect of low flow sevoflurane in treatment of laparoscopic operation anesthesia.Methods110 cases of patients with laparoscopic operation were selected as the research objects, which were cured in our hospital from May 2014 to May 2015. According to the double blind method, they were divided into research group and control group with 55 cases in each. Patients in control group were treated with remifentanil anesthesia, and patients in research group were treated with low flow sevoflurane anesthesia.Results Pneumoperitoneum, 10 minutes after pneumoperitoneum and systolic pressure, diastolic blood pressure and heart rate during recovery from anesthesia of control group were all lower than those of research group. The differences were statistically significant (P<0.05).Extubation time, waking time of research group were (5.8±2.2) min and (8.2±3.2) min, which were all lower than those of control group with extubation time (10.4±4.5)min and waking time (14.8±2.4) min.The differences were statistically significant (P<0.05).Conclusion Low flow sevoflurane has

  13. 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.

  14. Lubrication Flows.

    Science.gov (United States)

    Papanastasiou, Tasos C.

    1989-01-01

    Discusses fluid mechanics for undergraduates including the differential Navier-Stokes equations, dimensional analysis and simplified dimensionless numbers, control volume principles, the Reynolds lubrication equation for confined and free surface flows, capillary pressure, and simplified perturbation techniques. Provides a vertical dip coating…

  15. 七氟醚与异氟醚低流量吸入麻醉临床应用对比分析%Comparative Clinical Applications of Low-flow Analysis Sevoflurane and Isoflurane in Inhalation Anesthesia

    Institute of Scientific and Technical Information of China (English)

    刘彦锋

    2015-01-01

    Objective To analyze and compare the clinical effects of low-flow inhalation sevoflurane and isoflurane anesthesia. Methods In March 2014 to February 2015 in our hospital underwent surgery patients require general anesthesia and tracheal intubation were randomly selected 70 cases observed object-oriented times,were divided into a control group and the observation group,each 35 cases. The control group received isoflurane anesthesia in patients in the observation group sevoflurane anesthesia administered to the patient,the clinical manifestations were recorded for both groups analyzed. Results Compared with the control group,the observation group were extubation time,recovery time and time aldrete scores were significantly lower,the difference was statistical y significant(P< 0.05),the control group and the observation group of patients with treatment satisfaction were 68.6 %,94.3% difference between the groups was statistical y significant(P< 0.05). Conclusion In terms of the relative ratio of isoflurane, sevoflurane anesthesia clinical effect is more pronounced,and safe,to help improve patient satisfaction.%目的:分析并对比七氟醚与异氟醚低流量吸入麻醉的临床效果。方法于2014年3月~2015年2月在我院行手术治疗时需全身麻醉和气管插管的患者中随机抽取70例为本次观察对象,平均分成对照组与观察组,每组各35例。对照组给予患者异氟醚麻醉,观察组给予患者七氟醚麻醉,对两组临床表现进行记录分析。结果与对照组相比,观察组患者拔管时间、苏醒时间及Aldrete评分时间均低,差异有统计学意义(P<0.05);对照组与观察组患者的治疗满意度分别为68.6%、94.3%,组间差异有统计学意义(P<0.05)。结论相对比异氟醚而言,七氟醚的麻醉临床效果更显著,且安全性高,有助于提高患者满意度。

  16. Flow Separation

    Science.gov (United States)

    1975-11-01

    FLOW Symboles t ; largeur de veine. 3 : constants de la loi de Gladstone-Dale (ici 3 = 0,227510-3 n3/kg). Cf s coefficient de frottement parietal...pas d̂ colleier.t Cf est le coefficient de frottement . L’indice 0 designe les conditions b l’origine de 1’interaction. (Le coefficient de frottement CL

  17. Media Flow

    DEFF Research Database (Denmark)

    Kabel, Lars

    2016-01-01

    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....

  18. Flow cytometry and cell sorting.

    Science.gov (United States)

    Ibrahim, Sherrif F; van den Engh, Ger

    2007-01-01

    Flow cytometry and cell sorting are well-established technologies in clinical diagnostics and biomedical research. Heterogeneous mixtures of cells are placed in suspension and passed single file across one or more laser interrogation points. Light signals emitted from the particles are collected and correlated to entities such as cell morphology, surface and intracellular protein expression, gene expression, and cellular physiology. Based on user-defined parameters, individual cells can then be diverted from the fluid stream and collected into viable, homogeneous fractions at exceptionally high speeds and a purity that approaches 100%. As such, the cell sorter becomes the launching point for numerous downstream studies. Flow cytometry is a cornerstone in clinical diagnostics, and cheaper, more versatile machines are finding their way into widespread and varied uses. In addition, advances in computing and optics have led to a new generation of flow cytometers capable of processing cells at orders of magnitudes faster than their predecessors, and with staggering degrees of complexity, making the cytometer a powerful discovery tool in biotechnology. This chapter will begin with a discussion of basic principles of flow cytometry and cell sorting, including a technical description of factors that contribute to the performance of these instruments. The remaining sections will then be divided into clinical- and research-based applications of flow cytometry and cell sorting, highlighting salient studies that illustrate the versatility of this indispensable technology.

  19. Synthetic Aperture Vector Flow Imaging

    DEFF Research Database (Denmark)

    Villagómez Hoyos, Carlos Armando

    The main objective of this project was to continue the development of a synthetic aperture vector flow estimator. This type of estimator is capable of overcoming two of the major limitations in conventional ultrasound systems: 1) the inability to scan large region of interest with high temporal...... resolutions; 2) the lack of capability in detecting flow other than the one along the direction of the beam. Addressing these technical limitations would translate in the clinic as a gain in valuable clinical information and a removal of operator-dependant sources of error, which would improve the diagnosis....... The main contribution of this work was the development of an angle estimator which features high accuracy and low standard deviation over the full 360◦ range. The estimator demonstrated its capability of operating at high frame rates (> 1000 Hz), and simultaneously detecting a large range of flow...

  20. The clinical application of reconstitution of deep femoral arterial blood flow in improving the ischemic symptoms of lower extremities%股深动脉血流重建改善下肢缺血的临床应用

    Institute of Scientific and Technical Information of China (English)

    陈国平; 顾建平; 楼文胜; 何旭; 陈亮; 苏浩波; 宋进华; 汪涛; 徐克

    2011-01-01

    Objective To investigate the clinical application of reconstitution of deep femoral arterial blood flow in improving the ischemic symptoms of lower extremities. Methods A total of 11 patients with arteriosclerosis obliteration received intravascular blood flow reconstitution by using deep femoral arteries as outflow tract or inflow tract when the superficial femoral arteries could not be reopened. The therapeutic effect was retrospectively analyzed. Six cases received percutaneous transluminal angioplasty ( PTA ) and/or stent implantation in iliac and common femoral arteries. while 4 cases only received PTA in deep f'emoral arteries.One case had PTA and/or stent placement in iliac and common femoral artery and only PTA in deep femoral artery at the same time. Results After operation, the pain gradually disappeared in 5 patients and skin temperature increased significantly. Of the five cases. toe ulcer exudation got dry in two after 3 days or after 10 days respectively, and the ulcers healed completely in 3 months when the follow-up was regularly conducted. In three cases the pain disturbed normal sleep before the treatment. which could not be relieved by common analgesics. After operation the pain occasionally appeared and could be tolerated even with no use of common analgesics. In one case the gangrenous toe fell off two months after the operation without surgical intervention. Because of severe lower extremity ischemia. two cases had to receive surgical limb amputations above knee. and the wound healed in one month. Two cases lost touch with the authors at 6-month follow-up, and intermittent claudication developed in five cases during follow-up period. After the treatment. the ankle-brachial index ( ABI ) became ( 0.71 ± 0.21 ). while it was ( 0.32 ± 0.19 ) before the treatment, the difference between the two was statistically signif'icant ( P <0.05). Conclusion When the iliofemoral artery or superficial femoral artery is extensively occluded , deep femoral

  1. 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 ℃ .

  2. 普适X射线无标定量相分析探讨%X- Ray Diffraction Method for Standard Less Quatitative Phase Analysis

    Institute of Scientific and Technical Information of China (English)

    沈春玉

    2004-01-01

    在无标定量相分析的基本原理上提出了一种新的无标定量相分析方法,该方法中不需要给出各个样品或各个相的质量吸收系数,试验条件温和,克服了各个样品中都要在全同的条件下进行的问题,扩大了应用范围,用于混合物样品的X射线衍射定量相分析,有利于提高定量相分析的精度.并对3种不同情况下推导出的表达式进行了探讨,结合JCPDS卡中的各相标准谱峰的相对强度分布数据,进行最小二乘方程组的抛弃平均法回归分析.研究结果表明,在各物相质量吸收系数已知或未知时,应用3种物相的混合物所做的实验都得到比较满意的结果.

  3. Clinical Research and Clinical Trials

    Science.gov (United States)

    ... NICHD Publications Data Sharing and Other Resources Research Clinical Trials & Clinical Research Skip sharing on social media links ... health care providers, and researchers. Find NICHD-Supported Clinical Trials Use this link to find a list of ...

  4. Clinical Competence/Clinical Credibility.

    Science.gov (United States)

    Goorapah, David

    1997-01-01

    In interviews with 10 nurse teachers and 10 clinicians, respondents could describe clinical competence more fluently than clinical credibility. Responses raised the question of whether nursing teachers must be clinically competent/credible to teach nursing. (SK)

  5. Estudio de confiabilidad de la prueba de sialometría para flujo no estimulado en sujetos adultos clínicamente sanos Study of reliability of the sialometry test for non-stimulated flow in clinically healthy adult individuals

    Directory of Open Access Journals (Sweden)

    J Aitken Saavedra

    2013-04-01

    Full Text Available Introducción: En personas sanas, la velocidad de flujo salival o sialometría (VFS puede afectarse por la edad, género y ritmo circadiano. No existe evidencia de la reproducibilidad de VFS no estimulada determinada en 5 minutos, en distintos momentos del día en un mismo individuo. Objetivos: Determinar confiabilidad de VFS no estimulada medida en 5 minutos, reproducibilidad en el tiempo y relación con rango etario y género. Metodología: Se determinó VFS durante 15 minutos en 42 individuos clínicamente sanos, con una mediana de 45.5 (30-65 años, entre 9 y 11 AM durante dos mañanas y entre 3 y 5 PM durante la tarde del segundo día de medición. La saliva se colectó en tubos separados durante 5 minutos y durante los 10 minutos restantes. El peso de las muestras fue expresado en ml/min. Los valores entre los grupos de estudio, se compararon mediante test t de Student, ANOVA y coeficiente de correlación de Spearman. Resultados: VFS promedio fue de 0.623 ± 0.329 y de 0.551 ± 0.289 a los 5 y 15 minutos respectivamente (p=0.001. VFS fue mayor en hombres a los 5 y 15 minutos (p=0.001. VFS en mujeres, disminuyó al aumentar la edad. No hubo diferencias en VFS a los 5 minutos (p=0.375 y a los 15 minutos (p=0.825, en distintos días y momentos del día, en un mismo individuo. Conclusión: VFS colectada durante 5 minutos, en un mismo individuo, presenta valores constantes en distintos días y momentos del día.Introduction: In healthy persons, the salivary flow rate (VFS or sialometry can be affected by the age, the gender and the circadian rhythm. There is no evidence of the reproducibility of the non-stimulated VFS determined in 5 minutes, in different moments of the day in the same individual. Aim: To determine the reliability of the non-stimulated VFS measured in 5 minutes, its reproducibility over time and its relation with the age range and the gender. Methodology: VFS was determined for 15 minutes in 42 clinically healthy individuals

  6. [Role of measurement of fractional flow reserve in coronary artery atherosclerosis].

    Science.gov (United States)

    Kopylovi, F Yu; Bykova, A A; Vasilevsky, Yu V; Simakov, S S

    2015-01-01

    The paper considers coronary flow in health and coronary flow autoregulation in health and disease. It gives basic methods used to estimate coronary flow reserve in patients with coronary atherosclerosis. The physiological bases for determining fractional flow reserve are presented. Clinical trials investigating the use of fractional flow reserve in patients with coronary heart disease are analyzed.

  7. 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.

  8. 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.

  9. 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 ...

  10. 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.)

  11. 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.

  12. Gas flow measurement using laminar flow elements

    Energy Technology Data Exchange (ETDEWEB)

    Weigand, J. [Meriam Instrument, Cleveland, OH (United States)

    1994-12-31

    An instrument that measures gas volumetric flow rate using a capillary tube laminar-flow principle is described. Irs construction, operation, accuracy, and rangeability are presented. Discussion includes integrating the differential-pressure-producing flowmeter with appropriate temperature find pressure devices to produce a digital flowmeter system capable of measuring volumetric and mass flow rates. Typical applications are described.

  13. 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

  14. 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

  15. Optimal Power Flow with Power Flow Routers

    OpenAIRE

    2016-01-01

    Power flow routing is an emerging control paradigm for the dynamic control of electric power flows. In this paper, we propose a generic model of a power flow router (PFR) and incorporate it into the optimal power flow (OPF) problem. First, a generic PFR architecture is proposed to encapsulate the desired functions of PFRs. Then, the load flow model of PFRs is developed and incorporated into the OPF framework. To pursue global optimality of the non-convex PFR-incorporated OPF (PFR-OPF) problem...

  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. Clinical Study on cerebral blood flow measured by color doppler ultrasound in healthy adults%经彩超测量健康成人脑血流量的临床研究

    Institute of Scientific and Technical Information of China (English)

    夏玉光; 肖艳萍; 曹振兴; 邓莉; 丁宝维

    2013-01-01

    Objective To explore the different changes of the adult cerebral blood flow with ages,different weight and gender,to summarize the changing characteristics of cerebral blood flow.Methods 360 cases of examination were divided into two groups according to gender,and were divided into five groups at different ages,and were divided into four groups according to body mass index,using TCD detector blood flow velocity.Results 196 cases of male physical examination,the mean cerebral blood flow was (969.37 ± 117.54)ml/min;the 164 females physical examination,the average cerebral blood flow was (987.76 ± 114.34)ml/min,there was no statistically significant difference (P< 0.05).Different ages cerebral blood flow velocity were different,20 to 29-year-old group and the 30 to 39-year-old group had no significant difference (P< 0.05) ;40 to 49-year-old group,50 to 59 years,60 to 69 years old< 70 age group significantly declined compoued with the first two groups,there was significant difference (P<0.05) ;there were significant difference between the four groups (P<0.05).Overweight and obese group were significantly lower than the light and the normal group,there was a statistically significant difference (P<0.05).Conclusion TCDcan be a sensitive and accurate hemodynamic changes in the human brain,and is very important in the early diagnosis,prevention,treatment,and follow-up of cerebrovascular disease.%目的 探讨不同年龄段成人脑血流量随体质量、性别等不同而出现的差异性改变,总结脑血流量不断发展的特征.方法 360例查体者,按照性别分成两组,应用TCD检测血流速度;按不同年龄段分成五组,应用TCD检测血流速度;按照体质量指数分成四组,应用TCD检测血流速度.结果 196例男性体检者,平均脑血流量(969.37±117.54) ml/min;164例女性体检者,平均脑血流量(987.76±114.34)ml/min,两组比较差异无统计学意义(P>0.05).不同年龄段脑血流速度血流速度有差异,其中20

  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 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。

  20. Evolution and Flow.

    Science.gov (United States)

    Csikszentmihalyi, Mihaly

    1997-01-01

    Presents flow theory in the context of evolution. Defines the elements of "flow" and contends that flow results in an optimal state of inner harmony which improves one's chance for survival. Identifies consequences of flow for creativity, peak performance, talent development, productivity, self-esteem, and stress reduction. Examines the…

  1. The Humidity in a Low-Flow Dräger Fabius Anesthesia Workstation with or without Thermal Insulation or a Heat and Moisture Exchanger: A Prospective Randomized Clinical Trial

    Science.gov (United States)

    de Oliveira, Sergius A. R.; Lucio, Lorena M. C.; Modolo, Norma S. P.; Hayashi, Yoko; Braz, Mariana G.; de Carvalho, Lídia R.; Braz, Leandro G.; Braz, José Reinaldo C.

    2017-01-01

    Background During anesthesia, as compared with intensive care, the time of the tracheal intubation is much shorter. An inhaled gas minimum humidity of 20 mgH2O.L-1 is recommended to reduce the deleterious effects of dry gas on the airways during anesthesia with tracheal intubation. The Fabius GS Premium® anesthesia workstation (Dräger Medical, Lübeck, Germany) has a built-in hotplate to heat gases in the breathing circuit. A heat and moisture exchanger (HME) is used to further heat and humidify the inhaled gas. The humidity of the gases in the breathing circuit is influenced by the ambient temperature. We compared the humidity of the inhaled gases from a low-flow Fabius anesthesia workstation with or without thermal insulation (TI) of the breathing circuit and with or without an HME. Methods We conducted a prospective randomized trial in 41 adult female patients who underwent elective abdominal surgery. The patients were allocated into four groups according to the devices used to ventilate their lungs using a Dräger Fabius anesthesia workstation with a low gas flow (1 L.min-1): control, with TI, with an HME or with TI and an HME (TIHME). The mean temperature and humidity of the inhaled gases were measured during 2-h after connecting the patients to the breathing circuit. Results The mean inhaled gas temperature and absolute humidity were higher in the HME (29.2±1.3°C; 28.1±2.3 mgH2O·L-1) and TIHME (30.1±1.2°C; 29.4±2.0 mgH2O·L-1) groups compared with the control (27.5±1.0°C; 25.0±1.8 mgH2O·L-1) and TI (27.2±1.1°C; 24.9±1.8 mgH2O·L-1) groups (P = 0.003 and P<0.001, respectively). Conclusions The low-flow Fabius GS Premium breathing circuit provides the minimum humidity level of inhaled gases to avoid damage to the tracheobronchial epithelia during anesthesia. TI of the breathing circuit does not increase the humidity of the inhaled gases, whereas inserting an HME increases the moisture of the inhaled gases closer to physiological values. PMID

  2. Clinical Trials

    Science.gov (United States)

    ... they are receiving. Other clinical trials involve a crossover design, where participants are randomly assigned to take a new treatment, a treatment already in use, and/or a placebo for a specified time ... If I am involved in a "crossover" clinical trial, can I go back to the ...

  3. Ischemic postconditioning: a clinical perspective

    DEFF Research Database (Denmark)

    Lønborg, Jacob; Treiman, Marek; Engstrøm, Thomas

    2010-01-01

    Primary percutaneous coronary intervention is the recommended therapy for patients with STelevation myocardial infarction. However, restoration of coronary blood flow may lead to reperfusion injury, which has been suggested to account for 50% of the final myocardial infarct size. As an adjuvant t...... discusses these issues with a clinical perspective and looks into alternative pharmacological cardioprotection....

  4. 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...

  5. 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...

  6. Ultrasonic 3-D vector flow method for quantitative in vivo peak velocity and flow rate estimation

    DEFF Research Database (Denmark)

    Holbek, Simon; Ewertsen, Caroline; Bouzari, Hamed;

    2017-01-01

    Current clinical ultrasound systems are limited to show blood flow movement in either 1-D or 2-D. In this paper, a method for estimating 3-D vector velocities in a plane using the Transverse Oscillation (TO) method, a 32 x 32 element matrix array, and the experimental ultrasound scanner SARUS...... is presented. The aim of this paper is to estimate precise flow rates and peak velocities derived from 3-D vector flow estimates. The emission sequence provides 3-D vector flow estimates at up to 1.145 frames per second in a plane, and was used to estimate 3-D vector flow in a cross sectional image plane....... The method is validated in two phantom studies, where flow rates are measured in a flow-rig, providing a constant parabolic flow, and in a straight-vessel phantom (ø = 8 mm) connected to a flow pump capable of generating time varying waveforms. Flow rates are estimated to be 82.1 ± 2.8 L/min in the flow...

  7. Ricci flow coupled with harmonic map flow

    CERN Document Server

    Müller, Reto

    2009-01-01

    We investigate a new geometric flow which consists of a coupled system of the Ricci flow on a closed manifold M with the harmonic map flow of a map phi from M to some closed target manifold N with a (possibly time-dependent) positive coupling constant alpha. This system can be interpreted as the gradient flow of an energy functional F_alpha which is a modification of Perelman's energy F for the Ricci flow, including the Dirichlet energy for the map phi. Surprisingly, the coupled system may be less singular than the Ricci flow or the harmonic map flow alone. In particular, we can always rule out energy concentration of phi a-priori - without any assumptions on the curvature of the target manifold N - by choosing alpha large enough. Moreover, if alpha is bounded away from zero it suffices to bound the curvature of (M,g(t)) to also obtain control of phi and all its derivatives - a result which is clearly not true for alpha = 0. Besides these new phenomena, the flow shares many good properties with the Ricci flow...

  8. Accreditation of flow cytometry in Europe.

    Science.gov (United States)

    Sack, Ulrich; Barnett, David; Demirel, Gulderen Yanikkaya; Fossat, Chantal; Fricke, Stephan; Kafassi, Nikolitsa; Nebe, Thomas; Psarra, Katherina; Steinmann, Jörg; Lambert, Claude

    2013-05-01

    ISO 15189 has been introduced to enable any clinical laboratory, irrespective of geographic location, to be accredited against internationally recognized standards and therefore facilitate direct international comparison of laboratories. Together with increasing use of ISO 15189 for standardization and competition purposes, often triggered by demands of patients and clinicians, clinical flow cytometry laboratories are becoming increasingly challenged to introduce compliant quality management systems. Whilst in most countries, ISO 15189 accreditation is not yet compulsory, there is increasing evidence to suggest that the implementation of this standard is growing. As a result, the European Society of Clinical Cell Analysis (ESCCA) has analysed the impact of accreditation in clinical flow cytometry laboratories. It found, through a discussion forum, that staff qualification, adaptation of multicolour antibody panels, and implementation of a comprehensive quality system (including quality assessment) have been identified as major challenges.

  9. Mobile flow cytometer for mHealth.

    Science.gov (United States)

    Balsam, Joshua; Bruck, Hugh Alan; Rasooly, Avraham

    2015-01-01

    Flow cytometry is used for cell counting and analysis in numerous clinical and environmental applications. However flow cytometry is not used in mHealth mainly because current flow cytometers are large, expensive, power-intensive devices designed to operate in a laboratory. Their design results in a lack of portability and makes them unsuitable for mHealth applications. Another limitation of current technology is the low volumetric throughput rates that are not suitable for rapid detection of rare cells.To address these limitations, we describe here a novel, low-cost, mobile flow cytometer based on wide-field imaging with a webcam for large volume and high throughput fluorescence detection of rare cells as a simulation for circulating tumor cells (CTCs) detection. The mobile flow cytometer uses a commercially available webcam capable of 187 frames per second video capture at a resolution of 320 × 240 pixels. For fluorescence detection, a 1 W 450 nm blue laser is used for excitation of Syto-9 fluorescently stained cells detected at 535 nm. A wide-field flow cell was developed for large volume analysis that allows for the linear velocity of target cells to be lower than in conventional hydrodynamic focusing flow cells typically used in cytometry. The mobile flow cytometer was found to be capable of detecting low concentrations at flow rates of 500 μL/min, suitable for rare cell detection in large volumes. The simplicity and low cost of this device suggests that it may have a potential clinical use for mHealth flow cytometry for resource-poor settings associated with global health.

  10. Clinical Research

    DEFF Research Database (Denmark)

    Christensen, Irene

    2016-01-01

    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 s...... 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....

  11. 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

  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. 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

  14. Clinical Investigation.

    Science.gov (United States)

    1979-09-30

    Hiller, D.A., Elliott, J.P.: Tubal Ligation Syndrome Myth or Reality. Presented: Armed Forces Division of ACOG, New Orleans, Louisiana, October 1977...Molecular Weight Immunoreactive Glucagon Levels in Patients with the Post Prandial Syndrome . (Abst.) Western Society for Clinical Research, 1979. (3...Glucagon Levels in Patients witl the Post Prandial Syndrome . Presented: Western Society Meetings, Western Society for Clinical Research, February 1979. (3

  15. 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.

  16. Unsteady flow volumes

    Energy Technology Data Exchange (ETDEWEB)

    Becker, B.G.; Lane, D.A.; Max, N.L.

    1995-03-01

    Flow volumes are extended for use in unsteady (time-dependent) flows. The resulting unsteady flow volumes are the 3 dimensional analog of streamlines. There are few examples where methods other than particle tracing have been used to visualize time varying flows. Since particle paths can become convoluted in time there are additional considerations to be made when extending any visualization technique to unsteady flows. We will present some solutions to the problems which occur in subdivision, rendering, and system design. We will apply the unsteady flow volumes to a variety of field types including moving multi-zoned curvilinear grids.

  17. 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....

  18. Dynamic power flow controllers

    Science.gov (United States)

    Divan, Deepakraj M.; Prasai, Anish

    2017-03-07

    Dynamic power flow controllers are provided. A dynamic power flow controller may comprise a transformer and a power converter. The power converter is subject to low voltage stresses and not floated at line voltage. In addition, the power converter is rated at a fraction of the total power controlled. A dynamic power flow controller controls both the real and the reactive power flow between two AC sources having the same frequency. A dynamic power flow controller inserts a voltage with controllable magnitude and phase between two AC sources; thereby effecting control of active and reactive power flows between two AC sources.

  19. Cerebral blood flow assessment of preterm infants during respiratory therapy with the expiratory flow increase technique

    Directory of Open Access Journals (Sweden)

    Mariana Almada Bassani

    2016-06-01

    Full Text Available Abstract Objective: To assess the impact of respiratory therapy with the expiratory flow increase technique on cerebral hemodynamics of premature newborns. Methods: This is an intervention study, which included 40 preterm infants (≤34 weeks aged 8-15 days of life, clinically stable in ambient air or oxygen catheter use. Children with heart defects, diagnosis of brain lesion and/or those using vasoactive drugs were excluded. Ultrasonographic assessments with transcranial Doppler flowmetry were performed before, during and after the increase in expiratory flow session, which lasted 5min. Cerebral blood flow velocity and resistance and pulsatility indices in the pericallosal artery were assessed. Results: Respiratory physical therapy did not significantly alter flow velocity at the systolic peak (p=0.50, the end diastolic flow velocity (p=0.17, the mean flow velocity (p=0.07, the resistance index (p=0.41 and the pulsatility index (p=0.67 over time. Conclusions: The expiratory flow increase technique did not affect cerebral blood flow in clinically-stable preterm infants.

  20. 先天性心脏病胎儿脑血流动力学变化的临床研究%Clinical study of cerebrovascular blood flow dynamics in fetus with congenital heart disease

    Institute of Scientific and Technical Information of China (English)

    徐赣琼; 周启昌; 欧阳竹; 章鸣; 蒲大容; 田蕾琪; 谢锋; 曾施; 谭宜

    2010-01-01

    Objective To determine whether CHD modify cerebrovascular flow dynamics in CHD fetuses,and the influence on different types of CHD.Methods Two hundred normal fefuses and 159 fetuses who were diagnosed CHD by prenatal echocardiogram were studied.CHD fetuses were divided into 6 groups according to hemodynamics:hypoplastic left heart syndrome(HLHS,n=23),left-sided obstructive lesions(LSOL,n=19),hypoplastic right heart syndrome(HRHS,n=15),right-sided obstructive lesions (RSOL,n=33),septal defect(SD,n=36),conotruneal defects(CTD,n=33).The pulsatility index(PI) and the cerebroplacental Doppler ratio(CPR)of the middle cerebral artery(MCA)and umbilical artery(UA) in normal and CHD group were measured by color Doppler flow system.Results MCA-PI and CPR in HLHS,HRHS,RSOL,CTD and SD groups all decreased compared with normal fetuses(P0.05).Conclusions Fetuses with CHD had decreasing eerebrovascular impedance.Different types of CHD had different levels of eerebrovascular impedance,which indicated that different types of CHD induced different levels of cerebrovascular circulationcompensation.%目的 探讨先天性心脏病(CHD)对胎儿脑血流动力学的影响,及不同类型CHD对脑血流动力学的影响程度.方法 正常胎儿200例和产前超声心动图诊断为CHD胎儿159例,其中左心发育不良综合征(HLHS)23例,左心梗阻性病变(LSOL)19例,右心发育不良综合征(HRHS)15例,右心梗阻性病变(RSOL)33例,间隔缺损36例,圆锥动脉干畸形(CTD)33例.测量胎儿大脑中动脉搏动指数(MCA-PI)、脐动脉搏动指数(UA-PI)及脑/脐血管PL管PI比值(CPR).结果 HLHS、HRHS、RSOL、CTD及SD组胎儿的MCA-PI和CPR均较对照组减低,UA-PI均较对照组升高,差异均有统计学意义(P0.05).结论 宫内CHD胎儿出现脑血管阻力下降,不同类型CHD脑血管阻力的改变程度不同,提示不同类型CHD胎儿存在不同程度的脑循环代偿反应.

  1. 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

  2. A Nonideal Flow Experiment.

    Science.gov (United States)

    Gonzalez-Velasco, Juan Ramon; Elorriaga, Javier Bilbao

    1984-01-01

    Considers the deviation from the ideal flows of both a backmix tank and a backmix tank followed by a flow vessel. Background information, apparatus used, and experimental procedures are provided. Typical results are also provided and discussed. (JN)

  3. Counting RG flows

    OpenAIRE

    Gukov, Sergei

    2016-01-01

    Interpreting renormalization group flows as solitons interpolating between different fixed points, we ask various questions that are normally asked in soliton physics but not in renormalization theory. Can one count RG flows? Are there different "topological sectors" for RG flows? What is the moduli space of an RG flow, and how does it compare to familiar moduli spaces of (supersymmetric) dowain walls? Analyzing these questions in a wide variety of contexts --- from counting RG walls to AdS/C...

  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. Integer Equal Flows

    Energy Technology Data Exchange (ETDEWEB)

    Meyers, C A; Schulz, A S

    2009-01-07

    The integer equal flow problem is an NP-hard network flow problem, in which all arcs in given sets R{sub 1}, ..., R{sub {ell}} must carry equal flow. We show this problem is effectively inapproximable, even if the cardinality of each set R{sub k} is two. When {ell} is fixed, it is solvable in polynomial time.

  6. 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.

  7. Distributed Power Flow Controller

    NARCIS (Netherlands)

    Yuan, Z.

    2010-01-01

    In modern power systems, there is a great demand to control the power flow actively. Power flow controlling devices (PFCDs) are required for such purpose, because the power flow over the lines is the nature result of the impedance of each line. Due to the control capabilities of different types of P

  8. Free surface flow focusing

    NARCIS (Netherlands)

    Peters, I.R.

    2012-01-01

    Reducing the area through which a fluid is allowed to flow often leads to an increase of flow velocity. A familiar example of this is a garden hose, where one can change the rather weak stream that usually flows out into a strong jet by narrowing the orifice at the end of the hose. In this example,

  9. 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

  10. Clinical Investigations

    Science.gov (United States)

    1977-09-30

    Pregnancy with Fetal Intrauteri-ne Death, Missed Abortion or Hydatidiform ... 54 Work Unit No. 76/17 (FY76, T) The Effect of Uterine Blood Flow on...79920 DETAIL SHEET Prostaglandin E2, Efficacy Study for Termination of Pregnancy with TITLE: Fetal Intrauterine Death, Missed Abortion or Hydatidiform...Cryptococcus neoformans strains ............................. 19 Work Unit No. 75/27 (Fy74, C) Assessment of Ilediation Factors Involved in Chemical Pain

  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. [Changes of medico-pharmaceutical profession and private practice from the late 19th century to the early 20th century: ebb and flow of western pharmacies and clinics attached to pharmacy].

    Science.gov (United States)

    Lee, Heung-Ki

    2010-12-31

    This article examined i) how traditional medico-pharmaceutical custom from the late 19th century influenced such changes, ii) how medical laws of Daehan Empire and early colonial period influenced the differentiation of medico-pharmaceutical profession, and iii) what the responses of medico-pharmaceutical professionals were like, and arrived at following conclusions. First, in late Chosun, there was a nationwide spread of pharmacies (medicine room, medicine store) as general medical institutions in charge of prescription and medication as well as diagnosis. Therefore, Koreans' perception of Western medicine was not very different from that of traditional pharmacy. Second, Western pharmacies were established by various entities including oriental doctors, Western doctors and drug manufacturers.Their business ranged from medical consultation, prescription, medication and drug manufacture. This was in a way the extension of traditional medico-pharmaceutical custom, which did not draw a sharp line between medical and pharmaceutical practices. Also, regulations on medical and pharmaceutical business of Daehan Empire did not distinguish oriental and Western medicine. Third, clinics attached to pharmacy began to emerge after 1908, as some Western pharmacies that had grown their business based on selling medicine began to hire doctors trained in Western medicine. This trend resulted from Government General's control over medico-pharmaceutical business that began in 1908, following a large-scale dismissal of army surgeons trained in medical schools in 1907. Fourth, as specialization increased within medico-pharmaceutical business following the colonial medical law in early 1910s, such comprehensive business practices as Western pharmacy disappeared and existing businesses were differentiated into dealers of medical ingredients, drug manufacturer, patent medicine businessmen and herbalists. And private practice gradually became the general trend by establishment of medical

  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. The Clinical Analysis of High-flow Priapism in 10 Cases%高血流量性阴茎异常勃起10例临床诊分析

    Institute of Scientific and Technical Information of China (English)

    于建红; 李迎春; 王晓东; 童玉云; 覃云凌; 沈明

    2012-01-01

    Objective To investigate the diagnosis and treatment of priapism after injury. Methods Ten cases of priapism after injury (aged 26 to 42 years, mean 32 years) were included. Their symptoms were described as painless penis persistent erection >4 h, incompletely but constantly rigid of the penis which was able to increase rigidity with sexual stimulation. Blood taken from the cavernosa showed an arterial blood sample in all the cases. Perineal color Doppler ultrasound findings included the penis artery was limited expansion compared with the contralateral side and blood flow velocity increased, and took out the arterial spectrum with low speed and high impedance, a maximum width of about 0.8 cm, found dilatation of bilateral cavernous arteries, the initial diagnosis was high blood- flow priapism. But penis angiography examination revealed there were bilateral cavernous arteries- sinus- like gap fistula in 2 cases. Results After embolization, the priapism was softened gradually. In all cases, 24~48h soft drape- shaped recovery, there was growing morning erection after 2 to 4 weeks, and sexual life was recovered slowly after 3 to 6 months, erection hardness had no significant changes with preoperative. Rigiscan measure was normal. Regular follow- up was 1 to 3 years. Erected penis had no significant deviation and pain, fine hardness, satisfactory completion of sexual life after erections, but the duration of sexual life was shorten and frequency of sexual intercourse was reduced in 2 cases. Conclusions According to the typical history, physical examination and cavernous blood gas analysis, the priapism can be diagnosed initially, Color Doppler ultrasound and penile cavernous artery angiography have high diagnostic value. They can not only further confirm the diagnosis, but also determine the site of arterial fistula which artery embolization. Used of absorbable material to make super- selective pudendal artery embolization is currently the best option for the treatment

  15. 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

  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. 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 all...

  18. Clinical Trials

    Science.gov (United States)

    ... and her initial results. Nueva Esperanza Para Las Enfermedades Del Corazón 09/23/2014 Milena tuvo un ... Story 09/23/2014 Nueva Esperanza Para Las Enfermedades Del Corazón 09/23/2014 Children and Clinical ...

  19. 中低温低流量体外循环在婴儿心内直视手术的临床研究%Clinical Studies of Mild & Moderate Hypothermic and Low-flow Extracorporeal Circulation on the Baby Open-heart Surgery

    Institute of Scientific and Technical Information of China (English)

    郑晓宇; 叶宁; 黄洪; 邬少君; 吴文绪; 蒋斌; 张迎春

    2013-01-01

    Objective:To investigate safety and feasibility of the application of mild & moderate hypothermic and low-flow extracorporeal circulation while undergoing open-heart surgery to the infants with congenital heart disease.Method:40 sick babies admitted to our department who undergoing open-heart surgery were randomly divided them into obsewation group and control group.The 20 sick babies in control group were applied mild hypothermia and high-flow perfusion technique for open-heart surgery,while the other 20 sick babies in observation group with moderate hypothermia and low-flow perfusion technique for open-heart surgery.Compared the postoperative brain function and the intraoperative blood gas of the two groups.Result:The moderate hypothermia and low-flow perfusion venous oxygen saturation was above 80% without hypoxia acidosis blood gas,and blood lactate didn't elevate.There is no significant difference (P> 0.05) on the lactate concentration of the artery blood and internal jugular vein blood of the observation group and the control group at each time.The postoperative recovery was good without significant cardiopubnonary bypass-related complications.Conclusion:The application of mild & moderate hypothermic and low-flow extracorporeal circulation while undergoing open-heart surgery to the infants not only can satisfy the need of oxygen supply of the brain tissue,but also reduce the destruction to the blood,keep the surgical area clear and help to reduce the adverse reactions led by long time high-flow perfusion.It provides new means to carry out clinical brain protection of infants with complex congenital heart surgery.%目的:探讨先天性心脏病婴儿进行心内直视手术时,应用中低温低流量体外循环的安全性和可行性.方法:40例因先天性心脏病行心内直视手术患儿,随机分为观察组(n=20):应用中度低温低流量的灌注技术;对照组(n=20):应用浅低温高流量的灌注技术.记录转机时间、手术时

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

    DEFF Research Database (Denmark)

    Thomassen, Carsten

    2014-01-01

    If F is a (possibly infinite) subset of an abelian group Γ, then we define f(F,Γ) as the smallest natural number such that every f(F,Γ)-edge-connected (finite) graph G has a flow where all flow values are elements in F. We prove that f(F,Γ) exists if and only if some odd sum of elements in F equals...... some even sum. We discuss various instances of this problem. We prove that every 6-edge-connected graph has a flow whose flow values are the three roots of unity in the complex plane. If the edge-connectivity 6 can be reduced, then it can be reduced to 4, and the 3-flow conjecture follows. We prove...... 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...

  1. Clinical value of urine flow acceleration and maximum urinary flow-rate in diagnosing bladder outlet obstruction of patients with benign prostate hyperplasia%尿流加速度和最大尿流率诊断膀胱出口梗阻的价值

    Institute of Scientific and Technical Information of China (English)

    文建国; 崔林刚; 孟庆军; 任川川; 李金升; 吕宇涛; 张艳

    2012-01-01

    目的 比较尿流加速度(UFA)和最大尿流率(Qmax)诊断膀胱出口梗阻(BOO)的价值. 方法 分别选取50例前列腺增生(BPH)患者和50例健康者进行前列腺体积、UFA和Qmax测定.以P-Q图梗阻区作为参考标准,比较UFA和Qmax诊断BOO的灵敏度和特异性. 结果 BPH组UFA明显低于非BPH组(P<0.05).以UFA<2 ml/s2和Qmax<10 ml/s作为诊断BOO参考标准,灵敏度和特异度分别为88%、75%与81%、63%,与参考标准P-Q图提示梗阻一致性分析Kappa值分别为0.55比0.35. 结论 UFA可以作为诊断BPH患者BOO的依据之一.%Objective To assess the value of the urine flow acceleration(UFA)versus maximum urinary flow rate (Qmax) for diagnosis of bladder outlet obstruction (BOO) in benign prostate hyperplasia (BPH).Methods A total of 50 men with BPH and 50 normal men were included in this study.Urodynamic examinations were performed in all patients according to the recommendations of the International Continence Society.Prostate volume,UFA and Qmax of each patient were analyzed and the results were compared between two groups.Results The UFA and Qmax of BPH group were much lower than that of the control group [(2.05±0.85)ml/s2 vs.(4.60±1.25)ml/s2 ; (8.50±1.05)ml/s vs.(13.00±3.35)ml/s,P<0.05].The prostate volume in BPH group was increased compared with control group [(28.6±9.8) ml vs.(24.2±7.6)ml,P<0.05].As diagnosis standard of UFA<2.05 ml/s2 and Qmax< 10 ml/s,the sensitivity and specificity of UFA and Qmax in diagnosing BOO were (88%,75 %)vs.(81%,63%).While compared with the result of P-Q chart,the Kappa values in correspondence analysis were 0.55 vs.0.35.The sensitivity,specificity and Kappa value of UFA in diagnosing BOO in BPHs were slightly higher than that of Qmax in comparison with the gold standard (BOO diagnosed by P-Q figure).Conclusions The UFA is a useful urodynamics parameter in diagnosing BOO of BPH.

  2. 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.

  3. Clinical Studies

    DEFF Research Database (Denmark)

    Pallesen, Ulla

    and repair? Have new materials improved longevity? Are there still clinical and material problems to be solved? And what has the highest impact on longevity of posterior resin restorations – the material, the dentist, the patient or the tooth? These matters will be discussed on the basis of the literature......Within the last 25 years composite resin materials have in many countries successively replaced amalgam as a restorative for posterior teeth. Resin materials and bonding systems are continuously being improved by the manufactures, adhesive procedures are now included in the curriculum of most...... universities and practicing dentists restore millions of teeth throughout the World with composite resin materials. Do we know enough about the clinical performance of these restorations over time? Numerous in vitro studies are being published on resin materials and adhesion, some of them attempting to imitate...

  4. Memory clinics

    OpenAIRE

    Jolley, D; Benbow, S M; Grizzell, M

    2006-01-01

    Memory clinics were first described in the 1980s. They have become accepted worldwide as useful vehicles for improving practice in the identification, investigation, and treatment of memory disorders, including dementia. They are provided in various settings, the setting determining clientele and practice. All aim to facilitate referral from GPs, other specialists, or by self referral, in the early stages of impairment, and to avoid the stigma associated with psychiatric services. They bring ...

  5. Clinical practice

    OpenAIRE

    2011-01-01

    Cerebral palsy (CP) is the most common physical disability in early childhood. The worldwide prevalence of CP is approximately 2–2.5 per 1,000 live births. It has been clinically defined as a group of motor, cognitive, and perceptive impairments secondary to a non-progressive defect or lesion of the developing brain. Children with CP can have swallowing problems with severe drooling as one of the consequences. Malnutrition and recurrent aspiration pneumonia can increase the risk of morbidity ...

  6. Concentric Split Flow Filter

    Science.gov (United States)

    Stapleton, Thomas J. (Inventor)

    2015-01-01

    A concentric split flow filter may be configured to remove odor and/or bacteria from pumped air used to collect urine and fecal waste products. For instance, filter may be designed to effectively fill the volume that was previously considered wasted surrounding the transport tube of a waste management system. The concentric split flow filter may be configured to split the air flow, with substantially half of the air flow to be treated traveling through a first bed of filter media and substantially the other half of the air flow to be treated traveling through the second bed of filter media. This split flow design reduces the air velocity by 50%. In this way, the pressure drop of filter may be reduced by as much as a factor of 4 as compare to the conventional design.

  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. 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.

  9. TRANSIMS traffic flow characteristics

    CERN Document Server

    Nagel, K; Pieck, M; Donnelly, R; Barrett, C L; 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 versions of the TRANSIMS microsimulation.

  10. 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.

  11. 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.

  12. 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...

  13. Retinal flow cytometer.

    Science.gov (United States)

    Alt, C; Veilleux, I; Lee, H; Pitsillides, C M; Côté, D; Lin, C P

    2007-12-01

    The in vivo flow cytometer is an instrument capable of continuous, real-time monitoring of fluorescently labeled cells in the circulation without the need to draw blood samples. However, the original system probes a single vessel in the mouse ear; the small sample volume limits the sensitivity of the technique. We describe an in vivo retinal flow cytometer that simultaneously probes five artery-vein pairs in the mouse eye by circularly scanning a small laser spot rapidly around the optic nerve head. We demonstrate that the retinal flow cytometer detects about five times more cells per minute than the original in vivo flow cytometer does in the ear.

  14. Asymmetric flow networks

    OpenAIRE

    Olaizola Ortega, María Norma; Valenciano Llovera, Federico

    2012-01-01

    This paper provides a new model of network formation that bridges the gap between the two benchmark models by Bala and Goyal, the one-way flow model, and the two-way flow model, and includes both as particular extreme cases. As in both benchmark models, in what we call an "asymmetric flow" network a link can be initiated unilaterally by any player with any other, and the flow through a link towards the player who supports it is perfect. Unlike those models, in the opposite direction there is ...

  15. 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.

  16. 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.

  17. 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

  18. What Are Clinical Trials?

    Science.gov (United States)

    ... of this page please turn Javascript on. Feature: Clinical Trials What Are Clinical Trials? Past Issues / Fall 2010 Table of Contents Clinical ... conducted all the time. The Different Phases of Clinical Trials Clinical trials related to drugs are classified into ...

  19. 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 ...

  20. Participating in Clinical Trials

    Medline Plus

    Full Text Available ... Z > Participating in Clinical Trials: About Clinical Trials In This Topic About Clinical Trials Risks and Benefits ... of this page please turn Javascript on. Participating in Clinical Trials About Clinical Trials A Research Study ...

  1. 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

  2. High Frame Rate Synthetic Aperture 3D Vector Flow Imaging

    DEFF Research Database (Denmark)

    Villagómez Hoyos, Carlos Armando; Holbek, Simon; Stuart, Matthias Bo

    2016-01-01

    3-D blood flow quantification with high spatial and temporal resolution would strongly benefit clinical research on cardiovascular pathologies. Ultrasonic velocity techniques are known for their ability to measure blood flow with high precision at high spatial and temporal resolution. However......, current volumetric ultrasonic flow methods are limited to one velocity component or restricted to a reduced field of view (FOV), e.g. fixed imaging planes, in exchange for higher temporal resolutions. To solve these problems, a previously proposed accurate 2-D high frame rate vector flow imaging (VFI......) technique is extended to estimate the 3-D velocity components inside a volume at high temporal resolutions (

  3. Ultrasound Vector Flow Imaging: Part I: Sequential Systems

    DEFF Research Database (Denmark)

    Jensen, Jørgen Arendt; Nikolov, Svetoslav Ivanov; Yu, Alfred C. H.;

    2016-01-01

    The paper gives a review of the most important methods for blood velocity vector flow imaging (VFI) for conventional, sequential data acquisition. This includes multibeam methods, speckle tracking, transverse oscillation, color flow mapping derived vector flow imaging, directional beamforming......, and variants of these. The review covers both 2-D and 3-D velocity estimation and gives a historical perspective on the development along with a summary of various vector flow visualization algorithms. The current state-of-the-art is explained along with an overview of clinical studies conducted and methods...

  4. 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.

  5. 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

  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...

  7. 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.

  8. 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.)

  9. Flows around bacterial swarms

    Science.gov (United States)

    Dauparas, Justas; Lauga, Eric

    2015-11-01

    Flagellated bacteria on nutrient-rich substrates can differentiate into a swarming state and move in dense swarms across surfaces. A recent experiment (HC Berg, Harvard University) measured the flow in the fluid around the swarm. A systematic chiral flow was observed in the clockwise direction (when viewed from above) ahead of a E.coli swarm with flow speeds of about 10 μm/s, about 3 times greater than the radial velocity at the edge of the swarm. The working hypothesis is that this flow is due to the flagella of cells stalled at the edge of a colony which extend their flagellar filaments outwards, moving fluid over the virgin agar. In this talk we quantitatively test his hypothesis. We first build an analytical model of the flow induced by a single flagellum in a thin film and then use the model, and its extension to multiple flagella, to compare with experimental measurements.

  10. Vortex flow hysteresis

    Science.gov (United States)

    Cunningham, A. M., Jr.

    1986-01-01

    An experimental study was conducted to quantify the hysteresis associated with various vortex flow transition points and to determine the effect of planform geometry. The transition points observed consisted of the appearance (or disappearance) of trailing edge vortex burst and the transition to (or from) flat plate or totally separated flows. Flow visualization with smoke injected into the vortices was used to identify the transitions on a series of semi-span models tested in a low speed tunnel. The planforms tested included simple deltas (55 deg to 80 deg sweep), cranked wings with varying tip panel sweep and dihedral, and a straked wing. High speed movies at 1000 frames per second were made of the vortex flow visualization in order to better understand the dynamics of vortex flow, burst and transition.

  11. 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)

  12. Data flow modeling techniques

    Science.gov (United States)

    Kavi, K. M.

    1984-01-01

    There have been a number of simulation packages developed for the purpose of designing, testing and validating computer systems, digital systems and software systems. Complex analytical tools based on Markov and semi-Markov processes have been designed to estimate the reliability and performance of simulated systems. Petri nets have received wide acceptance for modeling complex and highly parallel computers. In this research data flow models for computer systems are investigated. Data flow models can be used to simulate both software and hardware in a uniform manner. Data flow simulation techniques provide the computer systems designer with a CAD environment which enables highly parallel complex systems to be defined, evaluated at all levels and finally implemented in either hardware or software. Inherent in data flow concept is the hierarchical handling of complex systems. In this paper we will describe how data flow can be used to model computer system.

  13. Flow in bedrock canyons.

    Science.gov (United States)

    Venditti, Jeremy G; Rennie, Colin D; Bomhof, James; Bradley, Ryan W; Little, Malcolm; Church, Michael

    2014-09-25

    Bedrock erosion in rivers sets the pace of landscape evolution, influences the evolution of orogens and determines the size, shape and relief of mountains. A variety of models link fluid flow and sediment transport processes to bedrock incision in canyons. The model components that represent sediment transport processes are increasingly well developed. In contrast, the model components being used to represent fluid flow are largely untested because there are no observations of the flow structure in bedrock canyons. Here we present a 524-kilometre, continuous centreline, acoustic Doppler current profiler survey of the Fraser Canyon in western Canada, which includes 42 individual bedrock canyons. Our observations of three-dimensional flow structure reveal that, as water enters the canyons, a high-velocity core follows the bed surface, causing a velocity inversion (high velocities near the bed and low velocities at the surface). The plunging water then upwells along the canyon walls, resulting in counter-rotating, along-stream coherent flow structures that diverge near the bed. The resulting flow structure promotes deep scour in the bedrock channel floor and undercutting of the canyon walls. This provides a mechanism for channel widening and ensures that the base of the walls is swept clear of the debris that is often deposited there, keeping the walls nearly vertical. These observations reveal that the flow structure in bedrock canyons is more complex than assumed in the models presently used. Fluid flow models that capture the essence of the three-dimensional flow field, using simple phenomenological rules that are computationally tractable, are required to capture the dynamic coupling between flow, bedrock erosion and solid-Earth dynamics.

  14. Absolute quantification of myocardial blood flow.

    Science.gov (United States)

    Yoshinaga, Keiichiro; Manabe, Osamu; Tamaki, Nagara

    2016-07-21

    With the increasing availability of positron emission tomography (PET) myocardial perfusion imaging, the absolute quantification of myocardial blood flow (MBF) has become popular in clinical settings. Quantitative MBF provides an important additional diagnostic or prognostic information over conventional visual assessment. The success of MBF quantification using PET/computed tomography (CT) has increased the demand for this quantitative diagnostic approach to be more accessible. In this regard, MBF quantification approaches have been developed using several other diagnostic imaging modalities including single-photon emission computed tomography, CT, and cardiac magnetic resonance. This review will address the clinical aspects of PET MBF quantification and the new approaches to MBF quantification.

  15. Clinical Research of Middle-Late Pregnancy Uterine Artery Blood Flow Resistance in Preeclampsia Prediction%妊娠中晚期子宫动脉血流阻力在子痫前期预测的临床研究

    Institute of Scientific and Technical Information of China (English)

    余玉华; 钟春华; 刘华俭; 许明明

    2016-01-01

    Objective: To study the clinical detection of vibration pregnancy middle-late uterine artery blood flow resistance in preeclampsia.Method: 30 patients with pregnancy middle-late preeclampsia and 30 cases of normal pregnant women were chose in our hospital from June 2013 to August 2014, according to the result of diagnosis they were divided into preeclampsia group and normal pregnancy group. Two groups of patients were detected with doppler ultrasound detection. The middle-late pregnancy uterine artery blood flow resistance results and quality of delivery of two groups were compared and analyzed.Result: The pulsation index (PI) and resistance index (RI) in the preeclampsia group were higher than the normal pregnancy group, 1 min Apgar score and neonatal weight were lower than the normal pregnancy group, the differences were statistically significant (P<0.05). Conclusion: In the process of the clinical diagnosis and treatment of pregnancy really late pregnant women, by color doppler monitoring of uterine artery S/D, PI, RI and early diastolic notch of normal pregnant women in different gestational age circulatory hemodynamic study, can be simple and effective to predict preeclampsia, so as to guide doctors take timely countermeasures, for early treatment, to reduce the incidence of preeclampsia and its complications and critical important clinical basis for maternal and infant mortality.%目的:探讨妊娠中晚期子宫动脉血流阻力在子痫前期的临床检测作用。方法:选取2013年6月-2014年8月本院收治的妊娠中晚期子痫前期患者30例与正常孕妇30例,根据诊断结果将其分为子痫前期组与正常妊娠组。两组患者行多普勒超声检测,对比分析两组患者在妊娠中晚期所进行的子宫动脉血流阻力结果及分娩质量。结果:子痫前期组产妇的搏动指数(PI)与阻力指数(RI)均高于正常妊娠组,1 min Apgar评分与新生儿体重均低于正常妊娠组,差

  16. Clinical guidelines.

    Science.gov (United States)

    Uppal, Elaine

    2016-01-01

    This article is part of the Advancing practice series which is aimed at exploring practice issues in more depth, considering topics that are frequently encountered and facilitating the development of new insights. Elaine Uppal focuses on the importance of all midwives developing guideline writing skills to ensure that local, national and international midwifery/maternity guidelines are up to date, relevant and reflect midwifery knowledge alongside 'gold' standard evidence. The article aims to consider the development, use and critical appraisal of clinical guidelines. It will define and explain guidelines; discuss their development and dissemination; and consider issues relating to their use in practice. Techniques to critique and develop guidelines using the AGREE tool will be outlined in the form of practice challenges to be undertaken by the individual or in a group.

  17. 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...

  18. 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.

  19. Small-Gap Flows

    Science.gov (United States)

    1984-04-01

    34’OF CALIFORNIA# BERKELEY, CA 5.1720 ft (45 642-141 SMALL- GAP FLOWS BY E. 0. TUCK REPORT No. NAUE 84-1 CONTRACT N00014-84-K-OU26 APRIL i984...Mechanics, 41 (1970) 769-792. 11 3. Shallow-Water Waves at Discontinuities Shallow-water waves represent perhaps the prototype small- gap flow , the...solving (4.4) we need "initial" conditions at the starting station z = 0, and "exit" conditions at the station z = L where the gap flow merges with the

  20. 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.

  1. Geophysical fluid flow experiment

    Science.gov (United States)

    Broome, B. G.; Fichtl, G.; Fowlis, W.

    1979-01-01

    The essential fluid flow processes associated with the solar and Jovian atmospheres will be examined in a laboratory experiment scheduled for performance on Spacelab Missions One and Three. The experimental instrumentation required to generate and to record convective fluid flow is described. Details of the optical system configuration, the lens design, and the optical coatings are described. Measurement of thermal gradient fields by schlieren techniques and measurement of fluid flow velocity fields by photochromic dye tracers is achieved with a common optical system which utilizes photographic film for data recording. Generation of the photochromic dye tracers is described, and data annotation of experimental parameters on the film record is discussed.

  2. 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 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....

  3. 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).

  4. Cerebral blood flow in the neonate.

    Science.gov (United States)

    Vutskits, Laszlo

    2014-01-01

    Ensuring adequate oxygenation of the developing brain is the cornerstone of neonatal critical care. Despite decades of clinical research dedicated to this issue of paramount importance, our knowledge and understanding regarding the physiology and pathophysiology of neonatal cerebral blood flow are still rudimentary. This review primarily focuses on currently available human clinical and experimental data on cerebral blood flow and autoregulation in the preterm and term infant. Limitations of systemic blood pressure values as surrogates for monitoring adequate cerebral oxygen delivery are discussed. Particular emphasis is placed on the high interindividual variability in cerebral blood flow values, vasoreactivity, and autoregulatory thresholds making the applications of normative values highly questionable. Technical and ethical difficulties to conduct such trials leave us with a near complete lack of knowledge on how pharmacological and surgical interventions impact on cerebral autoregulation. The ensemble of these works argues for the necessity of highly individualized care by taking advantage of continuous bedside monitoring of cerebral circulation. They also point to the urgent need for further studies addressing the exciting but difficult issue of cerebral blood flow autoregulation in the neonate.

  5. Computer-controlled positive displacement pump for physiological flow simulation.

    Science.gov (United States)

    Holdsworth, D W; Rickey, D W; Drangova, M; Miller, D J; Fenster, A

    1991-11-01

    A computer-controlled pump for use both in the study of vascular haemodynamics and in the calibration of clinical devices which measure blood flow is designed. The novel design of this pump incorporates two rack-mounted pistons, driven into opposing cylinders by a micro-stepping motor. This approach allows the production of nearly uninterrupted steady flow, as well as a variety of pulsatile waveforms, including waveforms with reverse flow. The capabilities of this pump to produce steady flow from 0.1 to 60 ml s-1, as well as sinusoidal flow and physiological flow, such as that found in the common femoral and common carotid arteries are demonstrated. Cycle-to-cycle reproducibility is very good, with an average variation of 0.1 ml s-1 over thousands of cycles.

  6. 彩色多普勒超声检测胎儿脐血流在宫内窘迫诊断中的临床价值%Clinical application value of color Doppler ultrasonic examination on fetal umbilical cord blood flow in diagnosis of fetal distress in uterus

    Institute of Scientific and Technical Information of China (English)

    陈冰; 郭蕾; 李春东

    2013-01-01

    Objective To investigate the clinical value of color fetal umbilical cord blood flow in diagnosis of fetal distress in uterus,and to analyze the features of umbilical cord blood flow indexes in distress in uteruses.Methods 300 pregnant women were selected.The peak values of umbilical arteries at end-systole (S),the peak values of umbilical arteries at end-diastole (D),the pulsation indexes (PI) and the resistance indexes (RI) were determined.Results The incidence of distress in uterus of the observation group (S/D≥3.0) was 83.33%,that of the control group (S/D<3.0) was 1.98%,and the difference between the two groups was statistically significant (P < 0.05).S/D,PI and RI values of fetuses under distress in uteruses were all significantly higher than those of the fetuses without distress in uteruses,and the differences were all statistically significant (P < 0.05).The differences in umbilical cord blood flow S/D values before birth between the two groups had no statistical significance (P > 0.05) ; in latent phase,active phase and the second stage of labor,the umbilical cord blood flow S/D values of fetuses under distress in uteruses were gradually increased,while those of the fetuses without distress in uteruses changed insignificantly,and the differences between the two groups were statistically significant (P < 0.05).Conclusion Color Doppler ultrasonic examination on fetal umbilical cord blood flow can effectively screen fetal distress in uterus,is beneficial to early diagnosis and therapy,can promote the rehabilitation of the sick babies,and consequently is worthy of clinical generalization and application.%目的 探讨彩色多普勒超声检测胎儿脐血流对宫内窘迫诊断的临床价值,分析宫内窘迫胎儿脐血流指数特征.方法 采用99SOD-Ⅵ多普勒超声脐动脉血流分析仪检测300例分娩孕妇脐动脉收缩末期峰值(S)、舒张末期峰值(D)、搏动指数(PI)和阻力指数(RI),比较宫内窘迫胎儿及

  7. 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

  8. Martian Lava Flows

    Science.gov (United States)

    2005-01-01

    19 October 2005 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows lava flows at the southeast base of the giant volcano, Olympus Mons. The flat plain in the south-southeast (bottom/lower right) portion of the image is younger than and cuts off the ends of many of the lava flows that came from the northwest (upper left). Many of the lava flows in this image exhibit channels with levees bounding their margins. As each lava flow was advancing, its outer margins cooled and hardened, forming a channel or tube through which the molten rock continued to advance. Location near: 17.2oN, 129.0oW Image width: width: 3 km (1.9 mi) Illumination from: lower left Season: Northern Winter

  9. Web life: Ice Flows

    Science.gov (United States)

    2016-11-01

    Computer and video gamers of a certain vintage will have fond memories of Lemmings, a game in which players must shepherd pixelated, suicidal rodents around a series of obstacles to reach safety. At first glance, Ice Flows is strikingly similar.

  10. 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.

  11. 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.

  12. The disappearance of flow

    CERN Document Server

    Soff, S; Hartnack, C; Stöcker, H; Greiner, W; Soff, S; Bass, S A; Hartnack, C; Stöcker, H; Greiner, W

    1995-01-01

    We investigate the disappearance of collective flow in the reaction plane in heavy-ion collisions within a microscopic model (QMD). A systematic study of the impact parameter dependence is performed for the system Ca+Ca. The balance energy strongly increases with impact parameter. Momentum dependent interactions reduce the balance energies for intermediate impact parameters b\\approx4.5 fm. Dynamical negative flow is not visible in the laboratory frame but does exist in the contact frame for the heavy system Au+Au. For semi-peripheral collisions of Ca+Ca with b\\approx6.5 fm a new two-component flow is discussed. Azimuthal distributions exhibit strong collectiv flow signals, even at the balance energy.

  13. 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...

  14. Cash Flow Planning.

    Science.gov (United States)

    Littman, George W., III

    1979-01-01

    Proper cash flow planning allows a school business administrator to determine the availability of cash for operating expenses, the need for bank loans to cover these expenses, and the availability of idle cash for investment. (Author)

  15. 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.

  16. 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...

  17. 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

  18. Retinal flow cytometer

    OpenAIRE

    Alt, C.; Veilleux, I.; H. Lee; Pitsillides, C. M.; Côté, D.; Lin, C.P.

    2007-01-01

    The in vivo flow cytometer is an instrument capable of continuous, real-time monitoring of fluorescently labeled cells in the circulation without the need to draw blood samples. However, the original system probes a single vessel in the mouse ear; the small sample volume limits the sensitivity of the technique. We describe an in vivo retinal flow cytometer that simultaneously probes five artery–vein pairs in the mouse eye by circularly scanning a small laser spot rapidly around the optic nerv...

  19. 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

  20. 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.

  1. Sperm Motility in Flow

    Science.gov (United States)

    Guasto, Jeffrey; Juarez, Gabriel; Stocker, Roman

    2012-11-01

    A wide variety of plants and animals reproduce sexually by releasing motile sperm that seek out a conspecific egg, for example in the reproductive tract for mammals or in the water column for externally fertilizing organisms. Sperm are aided in their quest by chemical cues, but must also contend with hydrodynamic forces, resulting from laminar flows in reproductive tracts or turbulence in aquatic habitats. To understand how velocity gradients affect motility, we subjected swimming sperm to a range of highly-controlled straining flows using a cross-flow microfluidic device. The motion of the cell body and flagellum were captured through high-speed video microscopy. The effects of flow on swimming are twofold. For moderate velocity gradients, flow simply advects and reorients cells, quenching their ability to cross streamlines. For high velocity gradients, fluid stresses hinder the internal bending of the flagellum, directly inhibiting motility. The transition between the two regimes is governed by the Sperm number, which compares the external viscous stresses with the internal elastic stresses. Ultimately, unraveling the role of flow in sperm motility will lead to a better understanding of population dynamics among aquatic organisms and infertility problems in humans.

  2. 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.

  3. Jamming in Hopper Flow

    Science.gov (United States)

    Sadighpour, Sepehr; Mort, Paul; Behringer, R. P.

    2007-11-01

    It known that the flow rate, m, of sand from a hopper is independent of the amount of material in the hopper due to stress screening. This is the basis for the Beverloo equation which relates m to an effective fluidized region near the outlet. We use the screening idea to characterize the probability of jamming for flow from a hopper. We focus on the probability Ps(t) = 1 - Pj(t) that flow has continued without a jam, a `survival' probability. Screening suggests that in time dt, the jamming probability is dPj= dt/T, where T is a constant characteristic time. Simple analysis gives Ps(t) = (-t/T) where t is the time since the start of flow. We can also write Ps(M) = [-M/(mT)], where M is the mass that has flowed out. We have carried out experiments in a quasi-2D hopper to test this idea. Our sand grains are photoelastic disks confined between two Plexiglas sheets. We obtain two types of data, first, data for s(t) and second, photoelastic images showing the force structures within the hopper during flow. We find that Ps is well described by an exponential. Ongoing work seeks to relate T to the properties of the material near the outlet.

  4. 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...

  5. Approximating hemodynamics of cerebral aneurysms with steady flow simulations.

    Science.gov (United States)

    Geers, A J; Larrabide, I; Morales, H G; Frangi, A F

    2014-01-03

    Computational fluid dynamics (CFD) simulations can be employed to gain a better understanding of hemodynamics in cerebral aneurysms and improve diagnosis and treatment. However, introduction of CFD techniques into clinical practice would require faster simulation times. The aim of this study was to evaluate the use of computationally inexpensive steady flow simulations to approximate the aneurysm's wall shear stress (WSS) field. Two experiments were conducted. Experiment 1 compared for two cases the time-averaged (TA), peak systole (PS) and end diastole (ED) WSS field between steady and pulsatile flow simulations. The flow rate waveform imposed at the inlet was varied to account for variations in heart rate, pulsatility index, and TA flow rate. Consistently across all flow rate waveforms, steady flow simulations accurately approximated the TA, but not the PS and ED, WSS field. Following up on experiment 1, experiment 2 tested the result for the TA WSS field in a larger population of 20 cases covering a wide range of aneurysm volumes and shapes. Steady flow simulations approximated the space-averaged WSS with a mean error of 4.3%. WSS fields were locally compared by calculating the absolute error per node of the surface mesh. The coefficient of variation of the root-mean-square error over these nodes was on average 7.1%. In conclusion, steady flow simulations can accurately approximate the TA WSS field of an aneurysm. The fast computation time of 6 min per simulation (on 64 processors) could help facilitate the introduction of CFD into clinical practice.

  6. Microfluidic Impedance Flow Cytometry Enabling High-Throughput Single-Cell Electrical Property Characterization

    Directory of Open Access Journals (Sweden)

    Jian Chen

    2015-04-01

    Full Text Available This article reviews recent developments in microfluidic impedance flow cytometry for high-throughput electrical property characterization of single cells. Four major perspectives of microfluidic impedance flow cytometry for single-cell characterization are included in this review: (1 early developments of microfluidic impedance flow cytometry for single-cell electrical property characterization; (2 microfluidic impedance flow cytometry with enhanced sensitivity; (3 microfluidic impedance and optical flow cytometry for single-cell analysis and (4 integrated point of care system based on microfluidic impedance flow cytometry. We examine the advantages and limitations of each technique and discuss future research opportunities from the perspectives of both technical innovation and clinical applications.

  7. 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.

  8. [Clinical research VI. Clinical relevance].

    Science.gov (United States)

    Talavera, Juan O; Rivas-Ruiz, Rodolfo

    2011-01-01

    Usually, in clinical practice the maneuver selected is the one that achieves a favorable outcome with a direct percentage of superiority of at least 10 %, or when the number needed to treat is approximately equal to 10. While this percentage difference is practical for estimating the magnitude of an association, we need to differentiate the impact measures (attributable risk, preventable fraction), measures of association (RR, OR, HR), and frequency measures (incidence and prevalence) applicable when the outcome is nominal. And we must identify ways to measure the strength of association and the magnitude of the association when the outcome variable is quantitative. It is not uncommon to interpret the measures of association as if they were impact measures. For example, for a RR of 0.68, it is common to assume a 32 % reduction of the outcome, but we must consider that this is a relative reduction, which comes from relations of 0.4/0.6, 0.04/0.06, or 0.00004/0.00006. However the direct reduction is 20 % (60 % - 40 %), 2 %, and 2 per 100,000, respectively. Therefore, to estimate the impact of a maneuver it is important to have the direct difference and/or NNT.

  9. 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.

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

    Institute of Scientific and Technical Information of China (English)

    ZHANG ZhiGuo; FAN YuBo; DENG XiaoYan; WANG GuiXue; ZHANG He; Robert GUIDOIN

    2008-01-01

    Small-dlameter 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 couldindeed 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. 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.

  12. Unraveling ultrafiltration of polysaccharides with flow field flow fractionation

    NARCIS (Netherlands)

    Ven, van de Wilbert; Pünt, Ineke; Kemperman, Antoine; Wessling, Matthias

    2009-01-01

    We used flow field flow fractionation (flow-FFF) coupled with multi-angle-light scattering (MALS) to study the conformation of alginate molecules in ultrapure water and in a 10 mM salt solution. In particular, we investigated the behavior of alginates under filtration conditions. The flow-FFF result

  13. 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.

  14. Comparison of PIV with 4D-Flow in a physiological accurate flow phantom

    Science.gov (United States)

    Sansom, Kurt; Balu, Niranjan; Liu, Haining; Aliseda, Alberto; Yuan, Chun; Canton, Maria De Gador

    2016-11-01

    Validation of 4D MRI flow sequences with planar particle image velocimetry (PIV) is performed in a physiologically-accurate flow phantom. A patient-specific phantom of a carotid artery is connected to a pulsatile flow loop to simulate the 3D unsteady flow in the cardiovascular anatomy. Cardiac-cycle synchronized MRI provides time-resolved 3D blood velocity measurements in clinical tool that is promising but lacks a robust validation framework. PIV at three different Reynolds numbers (540, 680, and 815, chosen based on +/- 20 % of the average velocity from the patient-specific CCA waveform) and four different Womersley numbers (3.30, 3.68, 4.03, and 4.35, chosen to reflect a physiological range of heart rates) are compared to 4D-MRI measurements. An accuracy assessment of raw velocity measurements and a comparison of estimated and measureable flow parameters such as wall shear stress, fluctuating velocity rms, and Lagrangian particle residence time, will be presented, with justification for their biomechanics relevance to the pathophysiology of arterial disease: atherosclerosis and intimal hyperplasia. Lastly, the framework is applied to a new 4D-Flow MRI sequence and post processing techniques to provide a quantitative assessment with the benchmarked data. Department of Education GAANN Fellowship.

  15. Robust Optical Flow Estimation

    Directory of Open Access Journals (Sweden)

    Javier Sánchez Pérez

    2013-10-01

    Full Text Available n this work, we describe an implementation of the variational method proposed by Brox etal. in 2004, which yields accurate optical flows with low running times. It has several benefitswith respect to the method of Horn and Schunck: it is more robust to the presence of outliers,produces piecewise-smooth flow fields and can cope with constant brightness changes. Thismethod relies on the brightness and gradient constancy assumptions, using the information ofthe image intensities and the image gradients to find correspondences. It also generalizes theuse of continuous L1 functionals, which help mitigate the effect of outliers and create a TotalVariation (TV regularization. Additionally, it introduces a simple temporal regularizationscheme that enforces a continuous temporal coherence of the flow fields.

  16. 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.

  17. 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…

  18. 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)

  19. Transport hub flow modelling

    OpenAIRE

    Despagne, Wilfried; Frenod, Emmanuel

    2014-01-01

    Purpose: The purpose of this paper is to investigate the road freight haulage activity. Using the physical and data flow information from a freight forwarder, we intend to model the flow of inbound and outbound goods in a freight transport hub. Approach: This paper presents the operation of a road haulage group. To deliver goods within two days to any location in France, a haulage contractor needs to be part of a network. This network handles the processing of both physical goods and data. We...

  20. 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.

  1. Gas speed flow transducer

    Directory of Open Access Journals (Sweden)

    Godovaniouk V. N.

    2011-08-01

    Full Text Available The design of a gas speed flow transducer using the coupling of gas speed and heat streams within the transducer itself is proposed. To maintain the heat balance between two thermoresistors under gas stream at different temperatures, it provides energy consumption monitoring. The detailed combined planar technology for the transducer production is presented. The worked-out measurement procedure allows to make measurements in the temperature range. Information enough to organize production of cheap, reliable and precise gas speed flow transducers is given.

  2. Types of Treatment: Clinical Trials

    Science.gov (United States)

    ... Disease Information Treatment Types of Treatment Clinical Trials Clinical Trials Clinical Trials SHARE: Print Glossary Taking part in a clinical ... for cancer are based on previous clinical trials. Clinical Trial Service: LLS provides personalized clinical trial navigation when ...

  3. 4D Flow MRI in Neuroradiology: Techniques and Applications.

    Science.gov (United States)

    Pereira, Vitor Mendes; Delattre, Benedicte; Brina, Olivier; Bouillot, Pierre; Vargas, Maria Isabel

    2016-04-01

    Assessment of the intracranial flow is important for the understanding and management of cerebral vascular diseases. From brain aneurysms and arteriovenous malformations lesions to intracranial and cervical stenosis, the appraisal of the blood flow can be crucial and influence positively on patients' management. The determination of the intracranial hemodynamics and the collateral pattern seems to play to a major role in the management of these lesions. 4D flow magnetic resonance imaging is a noninvasive phase contrast derived method that has been developed and applied in neurovascular diseases. It has a great potential if followed by further technical improvements and comprehensive and systematic clinical studies.

  4. 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.

  5. Exploration of 4D MRI blood flow using stylistic visualization.

    Science.gov (United States)

    van Pelt, Roy; Oliván Bescós, Javier; Breeuwer, Marcel; Clough, Rachel E; Gröller, M Eduard; ter Haar Romenij, Bart; Vilanova, Anna

    2010-01-01

    Insight into the dynamics of blood-flow considerably improves the understanding of the complex cardiovascular system and its pathologies. Advances in MRI technology enable acquisition of 4D blood-flow data, providing quantitative blood-flow velocities over time. The currently typical slice-by-slice analysis requires a full mental reconstruction of the unsteady blood-flow field, which is a tedious and highly challenging task, even for skilled physicians. We endeavor to alleviate this task by means of comprehensive visualization and interaction techniques. In this paper we present a framework for pre-clinical cardiovascular research, providing tools to both interactively explore the 4D blood-flow data and depict the essential blood-flow characteristics. The framework encompasses a variety of visualization styles, comprising illustrative techniques as well as improved methods from the established field of flow visualization. Each of the incorporated styles, including exploded planar reformats, flow-direction highlights, and arrow-trails, locally captures the blood-flow dynamics and may be initiated by an interactively probed vessel cross-section. Additionally, we present the results of an evaluation with domain experts, measuring the value of each of the visualization styles and related rendering parameters.

  6. 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.

  7. 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...

  8. 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,...

  9. 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 sh...

  10. 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...

  11. Power flow controller

    NARCIS (Netherlands)

    Ferreira, J.A.; Yuan, Z.; De Haan, S.W.H.

    2008-01-01

    The invention relates to a power flow controller, comprising at least one first converter coupled with a power transmission line, and at least one second converter coupled with a power source, wherein said power source operates at a predeter-mined first frequency and connects to the power transmissi

  12. Epiglottal Flow Physics

    Science.gov (United States)

    Pollard, Andrew; Shinneeb, Abdul-Monsif

    2011-11-01

    PIV measurements have been made at three locations in the pharynx/larynx region in the ETA model, one along the central sagittal plane and two cross-sectional planes. The measurements were made at a flow rate of 9.04 l/min which corresponds approximately to 10 l/min in the prototype. The corresponding Reynolds number Re based on the inlet condition is 716. Two thousand images were acquired at each location at a framing rate of 2 Hz. The mean velocity fields were then calculated. In addition,the data was analysed by the proper orthogonal decomposition (POD) technique to expose vortical structures. Only few modes were used for the POD reconstruction which recovered about 60% of the turbulent kinetic energy. The results showed that the flow is characterised by regions of re-circulation, jet-like, and sink-like flows. In addition, the POD-reconstructed fields revealed some interesting features that occur in the human pharynx/larynx region near the epiglottis such as tearing and pairing processes, as well as the interaction between the flows induced by the structures. Funded by NSERC.

  13. Infinitesimal Conical Supersonic Flow

    Science.gov (United States)

    Busemann, Adolf

    1947-01-01

    The calculation of infinitesimal conical supersonic flow has been applied first to the simplest examples that have also been calculated in another way. Except for the discovery of a miscalculation in an older report, there was found the expected conformity. The new method of calculation is limited more definitely to the conical case.

  14. Quaternions and ideal flows

    Energy Technology Data Exchange (ETDEWEB)

    Eshraghi, H [Iran University of Science and Technology (IUST), School of Physics, Institute for Studies in Theoretical Physics and Mathematics, Tehran (Iran, Islamic Republic of); Gibbon, J D [Department of Mathematics, Imperial College London, London SW7 2AZ (United Kingdom)

    2008-08-29

    After a review of some of the recent works by Holm and Gibbon on quaternions and their application to Lagrangian flows, particularly the incompressible Euler equations and the equations of ideal MHD, this paper investigates the compressible and relativistic Euler equations using these methods.

  15. 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.

  16. Low flow and economics of inhalational anaesthesia.

    Science.gov (United States)

    Odin, I; Feiss, P

    2005-09-01

    Even when anaesthesia does not represent a major part of the expense of a given surgical operation, reducing costs is not negligible because the large number of patients passing through a department of anaesthesia accounts for a huge annual budget. Volatile anaesthetics contribute 20% of the drug expenses in anaesthesia, coming just behind the myorelaxants; however, the cost of halogenated agents has potential for savings because a significant part of the delivered amount is wasted when a non- or partial-rebreathing system is used. The cost of inhaled agents is related to more than the amount taken up; it also depends on their market prices, their relative potencies, the amount of vapour released per millilitre of liquid, and last but not least the fresh-gas flow rate (FGF) delivered to the vaporizer--the most important factor determining the cost of anaesthesia. Poorly soluble agents like desflurane and sevoflurane facilitate the control of low-flow anaesthesia and reduce the duration of temporary high-flow phases to rapidly wash in or adjust the circuit gas concentrations. Modelling low-flow or minimal-flow anaesthesia will help anaesthetists to understand the kinetics of inhaled agents in those circumstances and to design their own clinical protocols. The monitoring facilities present on modern anaesthesia machines should convince clinicians that low- or even minimal-flow anaesthesia would not jeopardize the safety of their patients. Cost containment requires primarily a decrease in FGFs, but it may also be influenced by a rational use of the available halogenated agents. Isoflurane, the cheapest generic agent, might be advantageous for maintenance of anaesthesia of less than 3 hours. Sevoflurane is the agent of choice for inhalational induction and might also be used for maintenance. Desflurane might be preferred for long anaesthetics where rapid recovery will generate savings in the PACU.

  17. 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

  18. Clinical Application of Color Doppler Flow Imaging in the EnCor Vacuum Assisted Minimally Invasive Treatment For Breast lesions%彩超引导在EnCor真空辅助微创旋切乳腺良性肿块中的价值

    Institute of Scientific and Technical Information of China (English)

    王广珊; 杨世昕; 谢春伟; 李志华; 舒特标

    2013-01-01

    Objective?To explore clinical cpplication of color doppler flow imaging in the EnCor vacuum assisted minimally invasive treatment for breast lesions. Methods In under the guidance of ultrasound in 375 patients with 1081 lesions underwent minimally invasive treatment. Results All of breast lesions by ultrasonic guided minimally invasive treatment, 375 cases were benign lesions in pathological diagnosis of 372 cases, atypical hyperplasia, carcinoma in situ and invasive breast carcinoma 1 cases. Postoperative complications:6 cases of subcutaneous ecchymosis, hematoma in 3 cases, 1 cases of nipple blood discharge, local skin peeling breakage in 1 case. After the operation scar is not obvious, cosmetic effect is good, return of follow-up 6 months after operation. Found no residual lesions, recurrence, and no scar formation, breast shape normal, no abnormal skin tactile. Conclusion Color doppler flow imaging in the EnCor vacuum assisted minimally invasive treatment for breast lesions is a kind of effective, less complications, better cosmetic results of minimally invasive operation method, ultrasound is a key role in minimally invasive treatment for breast lesions.%目的:探讨彩超引导在EnCor真空辅助旋切系统切除乳腺病变的应用价值。方法均在超声引导下对375例1081个病灶行微创旋切治疗。结果全部乳腺肿物采用超声引导下旋切,375例病灶的病理诊断结果良性病灶372例,不典型性增生、原位癌和浸润性乳腺癌各1例。术后并发症:皮下瘀斑6例,血肿形成3例,乳头溢血1例,局部皮肤旋切破损1例。术后手术瘢痕不明显,效果良好,术后6个月返院复查。均未发现病灶残留、复发,且无切口瘢痕形成,乳房外形正常,皮肤触觉无异常。结论超声引导下EnCor真空辅助旋切系统切除乳腺良性肿块是一种有效、并发症较少、美容效果较好的微创手术方法,超声在肿块旋切术中起着关键性的作用。

  19. 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.

  20. Experimental investigation of stator flow in diagonal flow fan

    Science.gov (United States)

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

    2008-12-01

    Experimental investigations were conducted for the internal flow of the stator of the diagonal flow fan. Corner 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 corner wall. At low flow rate of 80-90 % of the design flow rate, the corner separation between the suction surface and the hub surface can be found, which become widely spread at 80 % of the design flow rate.

  1. Flow dynamics and energy efficiency of flow in the left ventricle during myocardial infarction.

    Science.gov (United States)

    Vasudevan, Vivek; Low, Adriel Jia Jun; Annamalai, Sarayu Parimal; Sampath, Smita; Poh, Kian Keong; Totman, Teresa; Mazlan, Muhammad; Croft, Grace; Richards, A Mark; de Kleijn, Dominique P V; Chin, Chih-Liang; Yap, Choon Hwai

    2017-03-31

    Cardiovascular disease is a leading cause of death worldwide, where myocardial infarction (MI) is a major category. After infarction, the heart has difficulty providing sufficient energy for circulation, and thus, understanding the heart's energy efficiency is important. We induced MI in a porcine animal model via circumflex ligation and acquired multiple-slice cine magnetic resonance (MR) images in a longitudinal manner-before infarction, and 1 week (acute) and 4 weeks (chronic) after infarction. Computational fluid dynamic simulations were performed based on MR images to obtain detailed fluid dynamics and energy dynamics of the left ventricles. Results showed that energy efficiency flow through the heart decreased at the acute time point. Since the heart was observed to experience changes in heart rate, stroke volume and chamber size over the two post-infarction time points, simulations were performed to test the effect of each of the three parameters. Increasing heart rate and stroke volume were found to significantly decrease flow energy efficiency, but the effect of chamber size was inconsistent. Strong complex interplay was observed between the three parameters, necessitating the use of non-dimensional parameterization to characterize flow energy efficiency. The ratio of Reynolds to Strouhal number, which is a form of Womersley number, was found to be the most effective non-dimensional parameter to represent energy efficiency of flow in the heart. We believe that this non-dimensional number can be computed for clinical cases via ultrasound and hypothesize that it can serve as a biomarker for clinical evaluations.

  2. 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

  3. Clinical evaluation of application of myocardial fractional flow reserve on elective percutaneous coronary intervention in patients with ST-segment elevation myocardial infarction%心肌血流储备分数指导ST段抬高心肌梗死患者择期经皮冠状动脉介入的临床评价

    Institute of Scientific and Technical Information of China (English)

    邬冬梅; 王慧峰; 王凤群; 王鲲; 张永红

    2015-01-01

    目的:探讨心肌血流储备分数(FFRmyo)对ST段抬高心肌梗死(STEMI)患者择期经皮冠状动脉介入治疗(PCI)的意义。方法 STEMI行早期溶栓治疗或血栓自溶择期冠状动脉造影(CAG)的患者75例,其中FFRmyo<0.75者33例,行PCI治疗21例(A组),拒绝行PCI 治疗12例(B组),FFRmyo≥0.75者42例(C组)。记录患者一般临床资料,比较各组罪犯血管特点及临床事件发生情况。结果各组患者一般临床资料无统计学差异。随访一年,患者临床事件包括死亡、心肌梗死、靶血管血运重建及再住院的总发生率在A组及C组均显著低于B组(分别为P<0.05)。结论 FFRmyo测定对STEMI患者制定合理的治疗策略具有参考价值。%Objective To explore the application of myocardial fractional flow reserve (FFRmyo) on elective percutaneous coronary intervention (PCI) in patients with ST-segment elevation myocardial infarction (STEMI). Methods In all, 75 STEMI patients undergoing early thrombolysis treatment or spontaneous recanalization with elective PCI were recruited in this study. There were 33 patients with FFRmyo0.05). Fellowed one year, the total incidence of the clinical events including death, myocardial infarction, target vessel revascularization and rehospitalization was significantly lower in both Group A and Group C compared with Group B (P<0.05, respectively). Conclusion FFRmyo detection has a reference value on the establishment of treatment strategies for patients with STEMI.

  4. How to use your peak flow meter

    Science.gov (United States)

    Peak flow meter - how to use; Asthma - peak flow meter; Reactive airway disease - peak flow meter; Bronchial asthma - peak flow meter ... If your airways are narrowed and blocked due to asthma, your peak flow values drop. You can ...

  5. 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.

  6. Synthetic aperture tissue and flow ultrasound imaging

    DEFF Research Database (Denmark)

    Nikolov, Svetoslav

    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......, on the other hand, can create a Bmode image with as little as 2 emissions, thus significantly speeding-up the scan procedure. The first part of the dissertation describes the synthetic aperture tissue imaging. It starts with an overview of the efforts previously made by other research groups. A classification...

  7. Self-Organized Network Flows

    CERN Document Server

    Helbing, D; Lämmer, S; Helbing, Dirk; Siegmeier, Jan; L\\"{a}mmer, Stefan

    2007-01-01

    A model for traffic flow in street networks or material flows in supply networks is presented, that takes into account the conservation of cars or materials and other significant features of traffic flows such as jam formation, spillovers, and load-dependent transportation times. Furthermore, conflicts or coordination problems of intersecting or merging flows are considered as well. Making assumptions regarding the permeability of the intersection as a function of the conflicting flows and the queue lengths, we find self-organized oscillations in the flows similar to the operation of traffic lights.

  8. 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

  9. Determinants of leptomeningeal collateral flow in stroke patients with a middle cerebral artery occlusion

    Energy Technology Data Exchange (ETDEWEB)

    Seeters, Tom van; Velthuis, Birgitta K. [University Medical Center Utrecht, Department of Radiology, Utrecht (Netherlands); Biessels, Geert Jan; Kappelle, L.J. [University Medical Center Utrecht, Department of Neurology, Brain Center Rudolf Magnus, Utrecht (Netherlands); Graaf, Yolanda van der [University Medical Center Utrecht, Julius Center for Health Sciences and Primary Care, Utrecht (Netherlands); Collaboration: on behalf of the Dutch acute stroke study (DUST) investigators

    2016-10-15

    Poor leptomeningeal collateral flow is related to worse clinical outcome in acute ischemic stroke, but the factors that determine leptomeningeal collateral patency are largely unknown. We explored the determinants of leptomeningeal collateral flow and assessed their effect on the relation between leptomeningeal collateral flow and clinical outcome. We included 484 patients from the Dutch acute stroke study (DUST) with a middle cerebral artery (MCA) occlusion. The determinants of poor leptomeningeal collateral flow (≤50 % collateral filling) were identified with logistic regression. We calculated the relative risk (RR) of poor leptomeningeal collateral flow in relation to poor clinical outcome (90-day modified Rankin Scale 3-6) using Poisson regression and assessed whether the determinants of leptomeningeal collateral flow affected this relation. Leptomeningeal collateral flow was poor in 142 patients (29 %). In multivariable analyses, higher admission glucose level (odds ratio (OR) 1.1 per mmol/L increase (95 % CI 1.0-1.2)), a proximal MCA occlusion (OR 1.9 (95 % CI 1.3-3.0)), and an incomplete posterior circle of Willis (OR 1.7 (95 % CI 1.1-2.6)) were independently related to poor leptomeningeal collateral flow. Poor leptomeningeal collateral flow was related to poor clinical outcome (unadjusted RR 1.7 (95 % CI 1.4-2.0)), and this relation was not affected by the determinants of leptomeningeal collateral flow. Our study shows that admission glucose level, a proximal MCA occlusion, and an incomplete ipsilateral posterior circle of Willis are determinants of leptomeningeal collateral flow that represent a combination of congenital, acquired, and acute factors. After adjustment for these determinants, leptomeningeal collateral flow remains related to clinical outcome. (orig.)

  10. 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...

  11. 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...

  12. 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.

  13. 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...

  14. Wet solids flow enhancemant

    Energy Technology Data Exchange (ETDEWEB)

    Caram, H.S.; Foster, N.; Wildman, D.J. [USDOE Pittsburgh Energy Technology Center, PA (United States)

    1996-12-31

    WE used glass beads of different sizes as.a model system to study the flow enhancing properties of Octadecyltrichlorosilane (OTS). 0TS provides Si(CH{sub 2}){sub 17}CH{sub 3} groups that bind with the surface hydrox groups to make it hydrophobic. Experimental data showed, indeed, that surface hydrophobicity promotes the flow of wet granular materials. Mixtures of different percentage of silanized/unsilanized particles were prepared for tensile strength measurements. The tensile strength decreased as more silanized particles were added to the samples. The relationship between dimensionless tensile strength and void fraction followed the correlation found by Pierrat (1994). Contact angles were larger for the silanized particles, as compared with unsilanized ones.

  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. 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.

  17. TEP process flow diagram

    Energy Technology Data Exchange (ETDEWEB)

    Wilms, R Scott [Los Alamos National Laboratory; Carlson, Bryan [Los Alamos National Laboratory; Coons, James [Los Alamos National Laboratory; Kubic, William [Los Alamos National Laboratory

    2008-01-01

    This presentation describes the development of the proposed Process Flow Diagram (PFD) for the Tokamak Exhaust Processing System (TEP) of ITER. A brief review of design efforts leading up to the PFD is followed by a description of the hydrogen-like, air-like, and waterlike processes. Two new design values are described; the mostcommon and most-demanding design values. The proposed PFD is shown to meet specifications under the most-common and mostdemanding design values.

  18. Studies in transonic flow

    OpenAIRE

    Mohan, S. R.

    1983-01-01

    This thesis is divided into, two distinct parts. Part I describes the design and development of an intermittent cryogenic wind-tunnel, in which the cold conditions are generated by the expansion of high pressure gas. The device uses a light piston moving in a tube and conditions during the running time are maintained constant by 'tuning' the piston motion, i. e. by Imatchingt the volumetric flow rate entering and leaving the tube. The results of the pilot tunnel (running tim...

  19. Vortex Flow Correlation

    Science.gov (United States)

    1981-01-01

    LITERATURE SURVEY OF WATER TUNNEL APPLICATIONS ..... ............ 5 3.1 Water Tunnel Applications .... ......... 5 3.2 Water Tunnel Flow Visualization...CORRELATION OF WATER TUNNEL VORTEX BREAKDOWN CHARACTERISTICS WITH WIND TUNNEL DATA ...... . 228 127 LARGE GOTHIC LEX GEOMETRY (NORTHROP WATER TUNNEL)AT 20...results. The program consisted of three major tasks, as follows: TASK I - Literature Survey of Water Tunnel Applica- tions. TASK II - Identification of

  20. 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 arbejd...

  1. Flow Encountering Abrupt Topography

    Science.gov (United States)

    2013-09-30

    deeper depths near 350 m at Helen Reef, northward flow of relatively salty water is seen. This salty water may serve as a tracer and may indicate...need further scrutiny since this system is intended for deep waters . Doppler sonars included the Hydrographic Doppler Sonar System (HDSS) with 50 and...each were done for bathymetry mapping. During the cross-shore surveys, additional deep water bathymetry was obtained with a majority of the area around

  2. Dynamics of Supercritical Flows

    Science.gov (United States)

    2012-08-26

    safety shoes, leather gloves, and ear muffs (noise protection as required). Cryogenic PPE: Cryogenic gloves, Cryogenic Body Apron, Full-Face shield...the fluid in the dark core assuming the shape of an inverted mushroom . The excitation is so violent that the dark core is fully mixed by the time the...vortical structures involving the inner jet flow were ejected in an inverted mushroom -like fashion at the excitation frequency (~3 kHz). Up to the

  3. Projectile Base Flow Analysis

    Science.gov (United States)

    2007-11-02

    S) AND ADDRESS(ES) DCW Industries, Inc. 5354 Palm Drive La Canada, CA 91011 8. PERFORMING ORGANIZATION...REPORT NUMBER DCW -38-R-05 9. SPONSORING / MONITORING AGENCY NAME(S) AND ADDRESS(ES) U. S. Army Research Office...Turbulence Modeling for CFD, Second Edition, DCW Industries, Inc., La Cañada, CA. Wilcox, D. C. (2001), “Projectile Base Flow Analysis,” DCW

  4. Leukocytes in capillary flow.

    Science.gov (United States)

    Schmid-Schönbein, G W; Lee, J

    1995-01-01

    During disease, the flow of blood cells through the capillary network is one of the most perilous events in the microcirculation. Capillary distensibility, cytoplasmic activity of endothelial cells, red cells and leukocytes play an important role in capillary perfusion. Occlusion of capillaries is one of the early signs of vascular failure and is encountered in many different conditions and organs. Adhesion of leukocytes to the endothelium via expression of membrane adhesion molecules leads to microvascular entrapment with capillary occlusion.

  5. 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...

  6. Flow pattern in reverse-flow centrifugal separators

    NARCIS (Netherlands)

    Peng, W; Hoffmann, AC; Boot, PJAJ; Udding, A; Dries, HWA; Ekker, A; Kater, J

    2002-01-01

    Experimental flow patterns, determined by Laser Doppler Anemometry (LDA) for two types of reverse-flow centrifugal separators, are presented. The flow patterns in (a) a conventional cylinder-on-cone cyclone with tangential inlet and (b) a swirl tube with vane-generated swirl and a cylindrical body a

  7. 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.

  8. Magnetohydrodynamics of blood flow.

    Science.gov (United States)

    Keltner, J R; Roos, M S; Brakeman, P R; Budinger, T F

    1990-10-01

    The changes in hydrostatic pressure and electrical potentials across vessels in the human vasculature in the presence of a large static magnetic field are estimated to determine the feasibility of in vivo NMR spectroscopy at fields as high as 10 T.A 10-T magnetic field changes the vascular pressure in a model of the human vasculature by less than 0.2%. An exact solution to the magnetohydrodynamic equations describing a conducting fluid flowing transverse to a static magnetic field in a nonconducting, straight, circular tube is used. This solution is compared to an approximate solution that assumes that no magnetic fields are induced in the fluid and that has led previous investigators to predict significant biological effects from static magnetic fields. Experimental results show that the exact solution accurately predicts the magnetohydrodynamic slowing of 15% NaCl flowing transverse to 2.3- and 4.7-T magnetic fields for fluxes below 0.5 liter/min while the approximate solution predicts a much more retarded flow.

  9. Conversational flow promotes solidarity.

    Science.gov (United States)

    Koudenburg, Namkje; Postmes, Tom; Gordijn, Ernestine H

    2013-01-01

    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.

  10. Clinical toxicology: clinical science to public health.

    Science.gov (United States)

    Bateman, D N

    2005-11-01

    1. The aims of the present paper are to: (i) review progress in clinical toxicology over the past 40 years and to place it in the context of modern health care by describing its development; and (ii) illustrate the use of clinical toxicology data from Scotland, in particular, as a tool for informing clinical care and public health policy with respect to drugs. 2. A historical literature review was conducted with amalgamation and comparison of a series of published and unpublished clinical toxicology datasets from NPIS Edinburgh and other sources. 3. Clinical databases within poisons treatment centres offer an important method of collecting data on the clinical effects of drugs in overdose. These data can be used to increase knowledge on drug toxicity mechanisms that inform licensing decisions, contribute to evidence-based care and clinical management. Combination of this material with national morbidity datasets provides another valuable approach that can inform public health prevention strategies. 4. In conclusion, clinical toxicology datasets offer clinical pharmacologists a new study area. Clinical toxicology treatment units and poisons information services offer an important health resource.

  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.

  12. 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.

  13. Clinical Trials in Vision Research

    Science.gov (United States)

    ... Eye Health Information > Clinical Trials in Vision Research Clinical Trials in Vision Research Clinical studies depend on people ... vision research in the United States. Basics of Clinical Trials What is a clinical trial? Clinical trials are ...

  14. Numerical Investigation on the Separated Flow of Axial Flow Stator in Diagonal Flow Fan

    Science.gov (United States)

    Kinoue, Yoichi; Shiomi, Norimasa; Setoguchi, Toshiaki; Kaneko, Kenji; Jin, Yingzi

    2010-06-01

    Experimental and numerical investigations were conducted for the internal flow of the stator of the diagonal flow fan. Corner separation near the hub surface and the suction surface of the stator blade are focused on. At low flow rate of 80% of the design flow rate, the corner separation between the suction surface and the hub surface can be found in both experimental and numerical results. Separation vortices are found in the computed oil flow on both suction and hub surfaces at 80% of the design flow rate in the three-dimensional numerical simulation.

  15. Transverse oscillation vector flow imaging for transthoracic echocardiography

    DEFF Research Database (Denmark)

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

    2015-01-01

    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. 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.

  17. Optical diagnostics of intermittent flows

    DEFF Research Database (Denmark)

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

    2007-01-01

    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...... 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...... is for the first time applied for diagnostics of the flow pattern in a closed cylinder with a rotating end face with the aim of studying the changeover from the steady axisymmetric to unsteady asymmetric flow over a wide range of flow parameters. It is found that such a transition is notable for azimuthal...

  18. 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...

  19. Flow list and test results

    Data.gov (United States)

    U.S. Environmental Protection Agency — These data accompany the manuscript 'Critical Review of Elementary Flows in LCA Data'. Each file presents a subgroup of the elementary flows (data used for analysis)...

  20. 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.

  1. 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

  2. SPECIFIC SOLUTIONS GROUNDWATER FLOW EQUATION

    OpenAIRE

    Syahruddin, Muhammad Hamzah

    2014-01-01

    Geophysic publication Groundwater flow under surface, its usually slow moving, so that in laminer flow condition can find analisys using the Darcy???s law. The combination between Darcy law and continuity equation can find differential Laplace equation as general equation groundwater flow in sub surface. Based on Differential Laplace Equation is the equation that can be used to describe hydraulic head and velocity flow distribution in porous media as groundwater. In the modeling Laplace e...

  3. Wilsonian flows and background fields

    CERN Document Server

    Litim, Daniel F; Litim, Daniel F.; Pawlowski, Jan M.

    2002-01-01

    We study exact renormalisation group flows for background field dependent regularisations. It is shown that proper-time flows are approximations to exact background field flows for a specific class of regulators. We clarify the role of the implicit scale dependence introduced by the background field. Its impact on the flow is evaluated numerically for scalar theories at criticality for different approximations and regularisations. Implications for gauge theories are discussed.

  4. Property fund flows and returns

    OpenAIRE

    Lee, Stephen L.

    2000-01-01

    This study is concerned with the impacts on property returns from property fund flows, and with the possibility of a reverse transmission from property fund flows to property returns. In other words this study investigates whether property returns “cause” fund flow changes, or whether fund flow changes “cause” property returns, or causality works in both directions.\\ud \\ud \\ud \\ud

  5. 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.

  6. The coronary slow flow phenomenon: a new cardiac "Y" syndrome?

    Science.gov (United States)

    Leone, Maria Cristina; Gori, Tommaso; Fineschi, Massimo

    2008-01-01

    The coronary slow flow phenomenon (CSFP) is an angiographic finding that is characterised by delayed progression of the contrast medium during coronary angiography. The mechanism of this phenomenon remains unknown. In the present paper, we revise the current evidence regarding this phenomenon and discuss recent findings from our group reporting increased resting resistances in patients with the CSFP. We report that these patients had preserved blood flow responses to the intracoronary infusion of the vasodilator papaverine, demonstrating that the CSFP is not necessarily associated with an abnormal coronary flow reserve. Based on these findings and on the review of the current literature, we concur with the concept proposed by Beltrame et al. that the CSFP should be considered a separate clinical entity. Further studies are necessary to describe the clinical characteristics, including the prognosis, of these patients and to identify potential treatments.

  7. Flow measurements in cardiac MRI; Flussmessungen in der kardialen MRT

    Energy Technology Data Exchange (ETDEWEB)

    Lotz, J. [Medizinische Hochschule Hannover, Institut fuer Diagnostische Radiologie, Hannover (Germany)

    2007-04-15

    Phase-contrast flow measurements have become an established method in cardiac MRI. The quantification of intra- and extracardiac shunt volumes as well as the evaluation of valvular disease and aortic coarctation have proved their clinical usefulness. There are some rules that have to be followed when performing and analyzing phase-contrast flow measurements. With these rules in mind, quantitative phase-contrast flow measurements are a reliable and precise method for clinical use of cardiac MRI. (orig.) [German] Flussmessungen gehoeren zum Standardrepertoire der MRT des Herzens. Dabei stehen die Quantifizierungen intra- und extrakardialer Shuntvolumina sowie von Klappenvitien im Vordergrund. Aber auch die Abschaetzung von Stenosen, beispielsweise des Aortenisthmus v. a. ueber einen assoziierten Kollateralfluss, sind klinisch akzeptiert. Bei der Planung und Auswertung einer Phasenkontrastflussmessung muessen einige Regeln beachtet werden, um fehlerhafte Ergebnisse zu vermeiden. Dann aber ist die Phasenkontrastflussmessung eine wertvolle Ergaenzung fuer die taegliche Routine in der Herzbildgebung. (orig.)

  8. 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.

  9. 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

  10. Risk assessment future cash flows

    OpenAIRE

    Chachina H. G.

    2012-01-01

    This article is about risk assessment in planning future cash flows. Discount rate in DCF-model must include four factors: risk cash flow, inflation, value of investments, turnover assets. This has an influence net present value cash flow and make his incomparable.

  11. EMBEDDING FLOWS AND SMOOTH CONJUGACY

    Institute of Scientific and Technical Information of China (English)

    ZHANGMEIRONG; LIWEIGU

    1997-01-01

    The authors use the functional equation for embedding vector fields to study smooth embedding flows of one-dimensional diffeomorphisms. The existence and uniqueness for smooth embedding flows and vector fields are proved. As an application of embedding flows, some classification results about local and giobal diffeomorphisms under smooth conjugacy are given.

  12. Decorrelation-based blood flow velocity estimation: effect of spread of flow velocity, linear flow velocity gradients, and parabolic flow.

    NARCIS (Netherlands)

    Lupotti, F.A.; Steen, A.F.W. van der; Mastik, F.; Korte, C.L. de

    2002-01-01

    In recent years, a new method to measure transverse blood flow, based on the decorrelation of the radio frequency (RF) signals has been developed. In this paper, we investigated the influence of nonuniform flow on the velocity estimation. The decorrelation characteristics of transverse blood flow us

  13. Localized turbulence in pipe flow

    NARCIS (Netherlands)

    Kuik, D.J.

    2011-01-01

    In this thesis the transition to turbulence in pipe flow is investigated. At low Reynolds numbers, the flow returns to the laminar state spontaneously. At high Reynolds number a small perturbation causes the flow to suddenly become turbulent. In the intermediate regime localized turbulence is observ

  14. 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

  15. Electroosmotic shear flow in microchannels

    NARCIS (Netherlands)

    Mampallil, Dileep; Ende, van den Dirk

    2013-01-01

    We generate and study electroosmotic shear flow in microchannels. By chemically or electrically modifying the surface potential of the channel walls a shear flow component with controllable velocity gradient can be added to the electroosmotic flow caused by double layer effects at the channel walls.

  16. Directional synthetic aperture flow imaging

    DEFF Research Database (Denmark)

    Jensen, Jørgen Arendt; Nikolov, Svetoslav

    2004-01-01

    A method for flow estimation using synthetic aperture imaging and focusing along the flow direction is presented. The method can find the correct velocity magnitude for any flow angle and full color flow images can be measured using only 32 to 128 pulse emissions. The approach uses spherical wave...... artery and jugular vein of a healthy 29 years old volunteer was acquired. A full color flow image using only 128 emissions could be made with a high velocity precision.......A method for flow estimation using synthetic aperture imaging and focusing along the flow direction is presented. The method can find the correct velocity magnitude for any flow angle and full color flow images can be measured using only 32 to 128 pulse emissions. The approach uses spherical wave...... angle is manually determined from the B-mode image. The approach can be used for both tissue and blood velocity determination. The approach was investigated using both simulations and a flow system with a laminar flow. The flow profile was measured with a commercial 7.5 MHz linear array transducer...

  17. Large amplitude oscillatory elongation flow

    DEFF Research Database (Denmark)

    Rasmussen, Henrik K.; Laillé, Philippe; Yu, Kaijia

    2008-01-01

    A filament stretching rheometer (FSR) was used for measuring the elongation flow with a large amplitude oscillative elongation imposed upon the flow. The large amplitude oscillation imposed upon the elongational flow as a function of the time t was defined as epsilon(t) =(epsilon) over dot(0)t + ...

  18. History of clinical pharmacy and clinical pharmacology.

    Science.gov (United States)

    Miller, R R

    1981-04-01

    The purpose of the Symposium on Clinical Pharmacy and Clinical Pharmacology is to describe the present and future functional roles of clinical pharmacists and clinical pharmacologists in drug research, professional education, and patient care. Clinical pharmacy is a relatively new professional discipline, being only about 15 years old. This new breed of pharmacists is patient rather than drug product oriented. The discipline arose out of dissatisfaction with old practice norms and the pressing need for a health professional with a comprehensive knowledge of the therapeutic use of drugs. The clinical pharmacy movement began at the University of Michigan in the early 1960s, but much of the pioneering work was done by David Burkholder, Paul Parker, and Charles Walton at the University of Kentucky in the latter part of the 1960s. Clinical pharmacology is a professional discipline that combines basic pharmacology and clinical medicine. Its development began in the early 1950s, primarily as a result of the efforts of Harry Gold. It has had a slower growth than clinical pharmacy but it has made many important contributions to our knowledge of human pharmacology and the rational use of drugs.

  19. Development of clinical scientists.

    Science.gov (United States)

    Smith, R V

    1987-01-01

    The education and training of clinical scientists has served society in several ways. For academic pharmacy, the emergence of clinical science has provided research and scholarship opportunities for clinical faculty development. Clinical scientists have also begun to play important roles in industrial drug research and development. For all faculty and students, clinical science research reinforces a "research mindset" that will become increasingly important as our society moves from a production/extraction to an information-based economy. Pharmacy will best evolve by increasing its commitment to clinical science research. In the process, academic pharmacy must continue to improve and support excellent education and training programs for clinical scientists.

  20. 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...

  1. Clinical algorithms to aid osteoarthritis guideline dissemination

    DEFF Research Database (Denmark)

    Meneses, S. R. F.; Goode, A. P.; Nelson, A. E

    2016-01-01

    Background: Numerous scientific organisations have developed evidence-based recommendations aiming to optimise the management of osteoarthritis (OA). Uptake, however, has been suboptimal. The purpose of this exercise was to harmonize the recent recommendations and develop a user-friendly treatment...... to facilitate the implementation of guidelines in clinical practice are necessary. The algorithms proposed are examples of how to apply recommendations in the clinical context, helping the clinician to visualise the patient flow and timing of different treatment modalities. (C) 2016 Osteoarthritis Research...

  2. Resting cerebral blood flow

    Science.gov (United States)

    Ances, B M.; Sisti, D; Vaida, F; Liang, C L.; Leontiev, O; Perthen, J E.; Buxton, R B.; Benson, D; Smith, D M.; Little, S J.; Richman, D D.; Moore, D J.; Ellis, R J.

    2009-01-01

    Objective: HIV enters the brain soon after infection causing neuronal damage and microglial/astrocyte dysfunction leading to neuropsychological impairment. We examined the impact of HIV on resting cerebral blood flow (rCBF) within the lenticular nuclei (LN) and visual cortex (VC). Methods: This cross-sectional study used arterial spin labeling MRI (ASL-MRI) to measure rCBF within 33 HIV+ and 26 HIV− subjects. Nonparametric Wilcoxon rank sum test assessed rCBF differences due to HIV serostatus. Classification and regression tree (CART) analysis determined optimal rCBF cutoffs for differentiating HIV serostatus. The effects of neuropsychological impairment and infection duration on rCBF were evaluated. Results: rCBF within the LN and VC were significantly reduced for HIV+ compared to HIV− subjects. A 2-tiered CART approach using either LN rCBF ≤50.09 mL/100 mL/min or LN rCBF >50.09 mL/100 mL/min but VC rCBF ≤37.05 mL/100 mL/min yielded an 88% (29/33) sensitivity and an 88% (23/26) specificity for differentiating by HIV serostatus. HIV+ subjects, including neuropsychologically unimpaired, had reduced rCBF within the LN (p = 0.02) and VC (p = 0.001) compared to HIV− controls. A temporal progression of brain involvement occurred with LN rCBF significantly reduced for both acute/early (<1 year of seroconversion) and chronic HIV-infected subjects, whereas rCBF in the VC was diminished for only chronic HIV-infected subjects. Conclusion: Resting cerebral blood flow (rCBF) using arterial spin labeling MRI has the potential to be a noninvasive neuroimaging biomarker for assessing HIV in the brain. rCBF reductions that occur soon after seroconversion possibly reflect neuronal or vascular injury among HIV+ individuals not yet expressing neuropsychological impairment. GLOSSARY AEH = acute/early HIV infection; ANOVA = analysis of variance; ASL-MRI = arterial spin labeling MRI; CART = classification and regression tree; CBF = cerebral blood flow; CH = chronic HIV

  3. Continuous information flow fluctuations

    Science.gov (United States)

    Rosinberg, Martin Luc; Horowitz, Jordan M.

    2016-10-01

    Information plays a pivotal role in the thermodynamics of nonequilibrium processes with feedback. However, much remains to be learned about the nature of information fluctuations in small-scale devices and their relation with fluctuations in other thermodynamics quantities, like heat and work. Here we derive a series of fluctuation theorems for information flow and partial entropy production in a Brownian particle model of feedback cooling and extend them to arbitrary driven diffusion processes. We then analyze the long-time behavior of the feedback-cooling model in detail. Our results provide insights into the structure and origin of large deviations of information and thermodynamic quantities in autonomous Maxwell's demons.

  4. 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

  5. Forecasting freight flows

    DEFF Research Database (Denmark)

    Lyk-Jensen, Stéphanie

    2011-01-01

    . This article models long-term dynamic physical trade flows and estimates a dynamic panel data model for foreign trade for the EU15 and two countries from the EFTA (European Free Trade Association) 1967–2002. The analysis suggests that a dynamic three-way-effects gravity equation is the best-fitted econometric...... model. The analysis uses a structural relationship to explain the structure of the exchange of the goods—a relationship that can be used in the year of forecast. This article also provides a new methodology for converting monetary aggregates into quantity aggregates. The resulting commodity growth rates...

  6. Disorders of lymph flow.

    Science.gov (United States)

    Witte, C L; Witte, M H

    1995-04-01

    Disturbances in blood capillary exchange of fluid, macromolecules, and cells across intact and abnormal microvessels and deranged lymphatic transport are integral, interacting components in disorders of tissue swelling. Lymphedema or low-output failure of the lymph circulation is often indolent for many years before lymphatic insufficiency (failure) and tissue swelling emerge and persist. Superimposed occult or overt infection (lymphangitis) are probably major contributors to progressive limb deformity (elephantiasis). Long-standing lymphedema is characterized by trapping in the skin and subcutaneous tissue of fluid, extravasated plasma proteins, and other macromolecules: impaired immune cell trafficking; abnormal processing of autologous and foreign antigens; heightened susceptibility to superimposed infection; local immunodysregulation; defective lymphatic (lymphangion) propulsion from an imbalance of mediators regulating vasomotion; soft-tissue overgrowth; scarring and hypertrophy; and exuberant angiogenesis occasionally culminating in vascular tumors (Fig. 8). In contrast to the blood circulation, where flow depends primarily on the propulsive force of the myocardium, lymph propulsion depends predominately on intrinsic truncal contraction, a phylogenetic vestige of amphibian lymph hearts. Whereas venous "plasma" flows rapidly (2-3 l/min) against low vascular resistance, lymph flows slowly (1-2 ml/min) against high vascular resistance. On occasion, impaired transport of intestinal lymph may be associated with reflux and accumulation and leakage of intestinal chyle in a swollen leg. Although the term "lymphedema" is usually reserved for extremity swelling, the pathogenesis of a wide variety of visceral disorders also may be traceable to defective tissue fluid and macromolecular circulation and impaired cell trafficking of lymphocytes and macrophages. Thus, lymph stasis, with impaired tissue fluid flow, underlies or complicates an indolent subclinical course with

  7. 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-

  8. Flow in air conditioned rooms

    DEFF Research Database (Denmark)

    Nielsen, Peter V.

    1974-01-01

    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......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...

  9. 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

  10. 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.

  11. Role of flow cytometry in the diagnosis and monitoring of primary immunodeficiency disease.

    Science.gov (United States)

    O'gorman, Maurice R G

    2007-09-01

    This presentation is organized according to the recent classification of primary immunodeficiencies published by the International Union of Immunological Societies Primary Immunodeficiency meeting. The diseases have been classified into eight groups. After each list, individual diseases that are amenable to assessment by flow cytometry are reviewed with a brief clinical description and a discussion of the appropriate flow cytometry application.

  12. Phase-Contrast Magnetic Resonance Angiography Measurements of Global Cerebral Blood Flow in the Neonate

    NARCIS (Netherlands)

    Benders, Manon J. N. L.; Hendrikse, Jeroen; de Vries, Linda S.; van Bel, Frank; Groenendaal, Floris

    2011-01-01

    Cerebral blood flow (CBF) alterations are important in pathogenesis of neonatal ischemic/hemorrhagic brain damage. In clinical practice, estimation of neonatal CBF is mostly based on Doppler-measured blood flow velocities in major intracranial arteries. Using phase-contrast magnetic resonance angiog

  13. 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.

  14. 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...... access blood flow measured before and after every procedure. Two methods, catheter-based thermodilution and Doppler ultrasound, were compared to the reference method of ultrasound dilution. Catheter-based thermodilution and Doppler ultrasound were performed during the endovascular procedures while flow...

  15. Reduced myocardial blood flow in acute and chronic digitalization.

    Science.gov (United States)

    Steiness, E; Bille-Brahe, N E; Hansen, J F; Lomholt, N; Ring-Larsen, H

    1978-07-01

    The myocardial blood flow was measured by the 133Xenon disappearance curve from the left ventricular wall following an injection of 133Xenon in the left coronary artery in 8 dogs without digoxin pretreatment and in 8 chronically digitalized dogs. The myocardial blood flow was significantly less (30%) in the digitalized dogs than in the dogs without pretreatment. In the digitalized dogs as well as in those without pretreatment an intravenous injection of digoxin resulted in a further significant decrease of the myocardial blood flow of about 20% and a significant increase of the coronary vascular resistance. The reduced myocardial blood flow both during acute and chronic digitalization is beleived to be of clinical importance.

  16. 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.

  17. Clinical approach to clinical herbal toxicity.

    Science.gov (United States)

    Tovar, Richard T

    2009-02-01

    This article is a review of the history and current status of herbs in the United States. The clinical effects of herbs and herbal medicine will be reviewed with respect to side effects and clinical toxicity. Treatment of herbal toxicity will be described where indicated.

  18. 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.

  19. Exotic RG Flows from Holography

    CERN Document Server

    Kiritsis, Elias; Pimenta, Leandro Silva

    2016-01-01

    Holographic RG flows are studied in an Einstein-dilaton theory with a general potential. The superpotential formalism is utilized in order to characterize and classify all solutions that are associated to asymptotically AdS space-times. Such solutions correspond to holographic RG flows and are characterized by their holographic $\\beta$-functions. Novel solutions are found that have exotic properties from a RG point-of view. Some have $\\beta$-functions that are defined patch-wise and lead to flows where the $\\beta$-function changes sign without the flow stopping. Others describe flows that end in non-neighboring extrema in field space. Finally others describe regular flows between two minima of the potential and correspond holographically to flows driven by the VEV of an irrelevant operator in the UV CFT.

  20. 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.

  1. Clinical application of CTA coupled with whole brain CT perfused blood flow after onset of aneurismal subarachnoid hemorrhage%CTA联合全脑血流灌注成像在蛛网膜下腔出血后的临床应用

    Institute of Scientific and Technical Information of China (English)

    李响; 李春志; 李松柏; 卑贵光; 蒋宝国; 徐克

    2011-01-01

    目的:探讨CTA联合全脑灌注成像在蛛网膜下腔出血(SAH)后的临床应用价值.方法:SAH病人29例,通过双源CT全脑血流灌注(PBV)检查,重建CTA图像和PBV图像,在检出动脉瘤等同时,以灌注参数评估SAH后脑血管痉挛及其所致的脑缺血改变情况.结果:29例病人中检出27例的28个动脉瘤.额、颞、顶、枕叶及小脑PBV值SAH组分别为11.17±3.13;10.92±2.91;11.08±2.53;9.88±3.01;19.83±5.12,对照组分别为17.10±3.60;15.98±5.03;15.84±3.53;16.14±1.86;23.54±4.64,额、顶、枕叶差异显著(P<0.05);存活组与死亡组各脑叶PBV值均未见显著性差异;优势出血侧和非优势出血侧低灌注出现情况无显著性差异.结论:CTA联合全脑PBV灌注成像能够在诊断SAH出血原因的同时显示脑血管痉挛引起的脑组织缺血改变.%Objective: To investigate the clinical application of CTA coupled with whole brain CT perfused blood flow after onset of aneurismal subarachnoid hemorrhage (SAH).Methods: Perfused blood volume (PBV) values were confirmed in 29 patients with SAH by dual source computed tomography.CTA maps and PBV maps were reconstructed.In the meantime we detectd the aneurysm, we evaluated the change of vasospasm and the cause of cerebral ischemia by the perfusion characteristics.Results: Twenty-eight aneurysms in 27 patients were detected.PBV value in the frontal, temporal, parietal, occipital lobe and cerebellum is 11.17±3.13; 10.92±2.91; 11.08±2.53; 9.88±3.01; 19.83±5.12 respectively in the SAH group, and 17.10±3.60; 15.98±5.03; 15.84±3.53; 16.14±1.86; 23.54±4.64 respectively in the control group.Significant difference was showed in the frontal, parietal and occipital lobes of the brain (P<0.05), but the PBV values had no significant difference in the survival group and the death group.It showed no significant difference of hypoperfusion between bleeding dominant hemisphere and the other one.Conclusions: The cause of the SAH could be

  2. 经鼻导管高流量加温湿化正压通气治疗新生儿呼吸窘迫综合征的临床疗效观察%Clinical Effect of Heating and Humidifying High - flow Positive Pressure Ventilation Through Nasal Catheter on Neonatal Respiratory Distress Syndrome

    Institute of Scientific and Technical Information of China (English)

    刘娟; 曾玲

    2016-01-01

    of 33. 3% ( P < 0. 05). Conclusion Heating and humidifying high - flow positive pressure ventilation through nasal catheter has certain clinical effect in treating neonatal respiratory distress syndrome,can effectively improve the oxygenation state,shorten the duration of oxygen therapy,hospital stays and time to start breastfeeding,reduce the incidence of complications.

  3. Active flows on trees

    Science.gov (United States)

    Forrow, Aden; Woodhouse, Francis G.; Dunkel, Jörn

    2016-11-01

    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 can interact 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. Our analytical predictions agree well 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 1 / 4 the number of edges. More broadly, these results suggest that the macroscopic response of active networks, from actin-myosin networks in cells to flow networks in Physarum polycephalum, can be dominated by a few select modes.

  4. Windstreak on Lava Flow

    Science.gov (United States)

    2005-01-01

    [figure removed for brevity, see original site] Today's image of the flows west of Arsia Mons also contains a large windstreak. Note the the surface texture in the 'white' part of the windstreak is more subdued than the rest of the flow. This is because the wind has deposited fine materials in this area. The wind can both erode the surface and cover it with deposits. Image information: VIS instrument. Latitude -7.7, Longitude 227.5 East (132.5 West). 17 meter/pixel resolution. Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time. NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

  5. Blood flow and microgravity

    Science.gov (United States)

    Bureau, Lionel; Coupier, Gwennou; Dubois, Frank; Duperray, Alain; Farutin, Alexander; Minetti, Christophe; Misbah, Chaouqi; Podgorski, Thomas; Tsvirkun, Daria; Vysokikh, Mikhail

    2017-01-01

    The absence of gravity during space flight can alter cardio-vascular functions partially due to reduced physical activity. This affects the overall hemodynamics, and in particular the level of shear stresses to which blood vessels are submitted. Long-term exposure to space environment is thus susceptible to induce vascular remodeling through a mechanotransduction cascade that couples vessel shape and function with the mechanical cues exerted by the circulating cells on the vessel walls. Central to such processes, the glycocalyx - i.e. the micron-thick layer of biomacromolecules that lines the lumen of blood vessels and is directly exposed to blood flow - is a major actor in the regulation of biochemical and mechanical interactions. We discuss in this article several experiments performed under microgravity, such as the determination of lift force and collective motion in blood flow, and some preliminary results obtained in artificial microfluidic circuits functionalized with endothelium that offer interesting perspectives for the study of the interactions between blood and endothelium in healthy condition as well as by mimicking the degradation of glycocalyx caused by long space missions. A direct comparison between experiments and simulations is discussed. xml:lang="fr"

  6. 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...

  7. 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.

  8. Clinical grades: upward bound.

    Science.gov (United States)

    Walsh, Catherine M; Seldomridge, Lisa A

    2005-04-01

    This study examined the relationship of grades earned in paired theory and clinical courses. Data collected during academic years 1997 to 2002 confirmed that grade inflation exists in clinical nursing courses. Problems involved in awarding grades for clinical performance are discussed (e.g., standards of clinical performance, methods used in evaluation of clinical performance, the impossibility of faculty omnipresence, the influence of student effort in grading, the effect of recency, the challenges of keeping good anecdotal records). Solutions to grading problems are proposed, including dividing up performance into agreed-on elements, measurement of these elements on a grading scale that allows for more differentiation of quality in evaluating clinical performance, assigning grades from the beginning of a clinical course, emphasizing all three domains of clinical practice, and evaluating student performance in both laboratory and, clinical settings.

  9. Clinical morphological parallels of traumatic skull

    OpenAIRE

    Shitikov T.A.

    2012-01-01

    In article the analysis of correlation dependences between clinical displays of 78 patient with brain trauma syndroms and adapted-trophic changes of an visual, craniometrical, MRI environment was spent. It was found that the pathobiomechanical researches are expedient, but in a complex estimation of structural and neurofunctional changes, which in most cases correlate with a degree of a significance of a cerebral blood flow and in a number of cases allow to determine a conducting pathogenetic...

  10. Automated High-Dimensional Flow Cytometric Data Analysis

    Science.gov (United States)

    Pyne, Saumyadipta; Hu, Xinli; Wang, Kui; Rossin, Elizabeth; Lin, Tsung-I.; Maier, Lisa; Baecher-Allan, Clare; McLachlan, Geoffrey; Tamayo, Pablo; Hafler, David; de Jager, Philip; Mesirov, Jill

    Flow cytometry is widely used for single cell interrogation of surface and intracellular protein expression by measuring fluorescence intensity of fluorophore-conjugated reagents. We focus on the recently developed procedure of Pyne et al. (2009, Proceedings of the National Academy of Sciences USA 106, 8519-8524) for automated high- dimensional flow cytometric analysis called FLAME (FLow analysis with Automated Multivariate Estimation). It introduced novel finite mixture models of heavy-tailed and asymmetric distributions to identify and model cell populations in a flow cytometric sample. This approach robustly addresses the complexities of flow data without the need for transformation or projection to lower dimensions. It also addresses the critical task of matching cell populations across samples that enables downstream analysis. It thus facilitates application of flow cytometry to new biological and clinical problems. To facilitate pipelining with standard bioinformatic applications such as high-dimensional visualization, subject classification or outcome prediction, FLAME has been incorporated with the GenePattern package of the Broad Institute. Thereby analysis of flow data can be approached similarly as other genomic platforms. We also consider some new work that proposes a rigorous and robust solution to the registration problem by a multi-level approach that allows us to model and register cell populations simultaneously across a cohort of high-dimensional flow samples. This new approach is called JCM (Joint Clustering and Matching). It enables direct and rigorous comparisons across different time points or phenotypes in a complex biological study as well as for classification of new patient samples in a more clinical setting.

  11. Immobilized Bioluminescent Reagents in Flow Injection Analysis.

    Science.gov (United States)

    Nabi, Abdul

    Available from UMI in association with The British Library. Bioluminescent reactions exhibits two important characteristics from an analytical viewpoint; they are selective and highly sensitive. Furthermore, bioluminescent emissions are easily measured with a simple flow-through detector based on a photomultiplier tube and the rapid and reproducible mixing of sample and expensive reagent is best achieved by a flow injection manifold. The two most important bioluminescent systems are the enzyme (luciferase)/substrate (luciferin) combinations extracted from fireflies (Photinus pyralis) and marine bacteria (Virio harveyi) which requires ATP and NAD(P)H respectively as cofactors. Reactions that generate or consume these cofactors can also be coupled to the bioluminescent reaction to provide assays for a wide range of clinically important species. A flow injection manifold for the study of bioluminescent reactions is described, as are procedures for the extraction, purification and immobilization of firefly and bacterial luciferase and oxidoreductase. Results are presented for the determination of ATP using firefly system and the determination of other enzymes and substrates participating in ATP-converting reactions e.g. creatine kinase, ATP-sulphurylase, pyruvate kinase, creatine phosphate, pyrophosphate and phophoenolypyruvate. Similarly results are presented for the determination of NAD(P)H, FMN, FMNH_2 and several dehydrogenases which produce NAD(P)H and their substrates, e.g. alcohol, L-lactate, L-malate, L-glutamate, Glucose-6-phosphate and primary bile acid.

  12. Eddy Current Minimizing Flow Plug for Use in Flow Conditioning and Flow Metering

    Science.gov (United States)

    England, John Dwight (Inventor); Kelley, Anthony R. (Inventor)

    2015-01-01

    An eddy-current-minimizing flow plug has open flow channels formed between the plug's inlet and outlet. Each open flow channel includes (i) a first portion that originates at the inlet face and converges to a location within the plug that is downstream of the inlet, and (ii) a second portion that originates within the plug and diverges to the outlet. The diverging second portion is approximately twice the length of the converging first portion. The plug is devoid of planar surface regions at its inlet and outlet, and in fluid flow planes of the plug that are perpendicular to the given direction of a fluid flowing therethrough.

  13. 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.

  14. Intraoperative multi-exposure speckle imaging of cerebral blood flow.

    Science.gov (United States)

    Richards, Lisa M; Kazmi, Sm Shams; Olin, Katherine E; Waldron, James S; Fox, Douglas J; Dunn, Andrew K

    2017-01-01

    Multiple studies have demonstrated that laser speckle contrast imaging (LSCI) has high potential to be a valuable cerebral blood flow monitoring technique during neurosurgery. However, the quantitative accuracy and sensitivity of LSCI is limited, and highly dependent on the exposure time. An extension to LSCI called multi-exposure speckle imaging (MESI) overcomes these limitations, and was evaluated intraoperatively in patients undergoing brain tumor resection. This clinical study ( n = 8) recorded multiple exposure times from the same cortical tissue area spanning 0.5-20 ms, and evaluated images individually as single-exposure LSCI and jointly using the MESI model. This study demonstrated that the MESI estimates provided the broadest flow sensitivity for sampling the flow magnitude in the human brain, closely followed by the shorter exposure times. Conservation of flow analysis on vascular bifurcations was used to validate physiological accuracy, with highly conserved flow estimates (blood flow changes after tissue cautery. Results from this study demonstrate that intraoperative MESI can be performed with high quantitative accuracy and sensitivity for cerebral blood flow monitoring.

  15. The flow regimes and the pressure-flow relationship in the canine urethra.

    Science.gov (United States)

    Lecamwasam, H S; Sullivan, M P; Yalla, S V; Cravalho, E G

    1999-01-01

    Classical fluid dynamics predicts that the pressure difference Deltap between any two points along a fully developed, viscous flow stream is linearly proportional to the flow rate Q (the Poiseuille relation). However, the passive urethral resistance relationship (PURR) widely used in modern urodynamics describes the pressure difference Deltap between two points along the urethra as linearly proportional to the flow rate squared (Q(2)). It is our hypothesis that this functional dependence may have its origins in the developing flow field within the urethra. That is, rather than being fully developed hydrodynamically, urethral flow is more likely representative of flow within the entry length of a rigid conduit. In our study, we used a canine model of the lower urinary tract to investigate the possibility of entrance effects. Although the most rigorous model of urethral fluid mechanics would include the elastic properties of the urethra into its configuration, the solutions from such a model would be unnecessarily complex and not readily lend themselves to the analysis of clinical data. Therefore, we chose to model the canine urethra at each instant in time as a rigid tube, and characterized its instantaneous flow using viscous flow theory for a rigid tube. All urodynamic analyses were performed on a surgically exposed urinary tract. Solid state pressure transducers were used to measure the intravesical and distal urethral pressures, whereas an ultrasonic flowmeter was used to obtain a simultaneous measure of the urinary flow rate. Detrusor contractions were induced using bilateral electrical stimulation of the pelvic nerves. Varying degrees of outlet obstruction were created using an inflatable sphincter cuff secured around the bladder outlet. The experimental data were evaluated using the well-known laminar entry length model of Atkinson and Goldstein. The peak Reynolds numbers under nonobstructed R(p)(e non-obs) and obstructed R(p)(e obs) outlet conditions ranged

  16. 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.

  17. How Do Clinical Trials Work?

    Science.gov (United States)

    ... Studies NHLBI Trials Clinical Trial Websites How Do Clinical Trials Work? If you take part in a clinical ... protect patients and help produce reliable study results. Clinical Trial Protocol Each clinical trial has a master plan ...

  18. 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...

  19. 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, ...

  20. Freely flowing conversations

    DEFF Research Database (Denmark)

    Aakjær, Marie Kirstejn; Andrade, David; Dexters, Peter

    2012-01-01

    on - and support “positive deviants” (Pascal, Sternin and Sternin) – courageous individuals and groups (inmates as well as staff) who transform conversations into new actions and behavioral traits that become beckons of an improved future. In the following we explore concrete examples of efforts at improving......Some would say this article is an impossibility - the authors being a project manager from the Department of Prisons an (ex) inmate and a Designer doing an industrial PhD in the prisons. We hope that others may see this article as an embodiment of how taking part in new conversations...... and in regards to rehabilitation efforts. In the context of prisons UDI is inspired by the complexity approach (Stacey 2005). We seek to facilitate freely flowing conversations between inmates, staff and managers – pushing the boundaries of existing norms, roles and beliefs. In the end however we rely...

  1. Saturation of Zonal Flows

    Science.gov (United States)

    Kim, Eun-Jin

    2002-11-01

    Zonal flows (ZF) are generated by drift wave (DW) turbulence and then regulate it near marginality by shear suppression. Since collisions damp ZF while ZF suppress DW, the amplitude of DW turbulence (i.e. turbulent transport) is, in turn, proportional to collisionality. A key question is then what happens away from marginality, namely what is the saturation mechanism of ZF in that regime? This raises the interesting physical question of how ZF interact with mne 0, poloidally non-axisymmetric modes [1], both linearly and non linearly. We investigate this issue by exploring the nonlinear excitation of GKH modes by modulational instability in the background of finite amplitude of DW turbulence, as well as the linear inflection-type instability of ZF. In a simple model with cold ions, we show that ZF can grow faster than the linear GKH for γ/ωGKH modes can be comparable to their linear generation. Here, γ and ω are the growth rate and frequency of DW, and p and k are the characteristic wavenumbers of ZF and DW. These findings imply that the linear analysis of GKH may not always be valid and also that there may be no clear distinction between secondary (ZF) and tertiary mode (GKH). The effect of finite ion temperature fluctuations is incorporated in a simple toroidal ion temperature gradient model, within which both zonal flow and temperature are generated by modulational instability. The phase between the two is calculated self-consistently and shown to be positive. Furthermore, the correction to nonlinear generation of GKH modes appears to be small. [1] We refer to these low mne 0 modes as Generalized Kelvin-Helmholtz (GKH) modes, since they will appear as mne 0 distortions of a shear layer.

  2. Informed Consent (Clinical Trials)

    Science.gov (United States)

    ... Research Cancer Treatment Types of Treatment Side Effects Clinical Trials Information A to Z List of Cancer Drugs ... Staging Prognosis Treatment Types of Treatment Side Effects Clinical Trials Cancer Drugs Complementary & Alternative Medicine Coping Feelings & Cancer ...

  3. 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.

  4. 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 ...

  5. 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,...

  6. Evidence of clinical competence.

    Science.gov (United States)

    Lejonqvist, Gun-Britt; Eriksson, Katie; Meretoja, Riitta

    2012-06-01

    This cross-sectional research used a qualitative questionnaire to explore clinical competence in nursing. The aim was to look for evidence of how clinical competence showed itself in practice. In the research, the views from both education and working life are combined to broadly explore and describe clinical competence from the perspective of students, clinical preceptors and teachers. The questions were formulated on how clinical competence is characterised and experienced, what contributes to it and how it is maintained, and on the relation between clinical competence and evidence-based care. The answers were analysed by inductive content analysis. The results showed that clinical competence in practice is encountering, knowing, performing, maturing and improving. Clinical competence is an ongoing process, rather than a state and manifests itself in an ontological and a contextual dimension.

  7. 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 ...

  8. 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...

  9. Spina Bifida Clinic Directory

    Science.gov (United States)

    ... edu Special Health Care Services Spinal Cord Clinic Wesley Medical Arts Tower Building (pediatric-will refer adults) ... to age 25) Clinic 6L, One Medical Center Dr. Lebanon, NH 03756 (603) 653-9623 http://chad. ...

  10. Joule heating in electrokinetic flow.

    Science.gov (United States)

    Xuan, Xiangchun

    2008-01-01

    Electrokinetic flow is an efficient means to manipulate liquids and samples in lab-on-a-chip devices. It has a number of significant advantages over conventional pressure-driven flow. However, there exists inevitable Joule heating in electrokinetic flow, which is known to cause temperature variations in liquids and draw disturbances to electric, flow and concentration fields via temperature-dependent material properties. Therefore, both the throughput and the resolution of analytic studies performed in microfluidic devices are affected. This article reviews the recent progress on the topic of Joule heating and its effect in electrokinetic flow, particularly the theoretical and experimental accomplishments from the aspects of fluid mechanics and heat/mass transfer. The primary focus is placed on the temperature-induced flow variations and the accompanying phenomena at the whole channel or chip level.

  11. 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.

  12. Flow, affect and visual creativity.

    Science.gov (United States)

    Cseh, Genevieve M; Phillips, Louise H; Pearson, David G

    2015-01-01

    Flow (being in the zone) is purported to have positive consequences in terms of affect and performance; however, there is no empirical evidence about these links in visual creativity. Positive affect often--but inconsistently--facilitates creativity, and both may be linked to experiencing flow. This study aimed to determine relationships between these variables within visual creativity. Participants performed the creative mental synthesis task to simulate the creative process. Affect change (pre- vs. post-task) and flow were measured via questionnaires. The creativity of synthesis drawings was rated objectively and subjectively by judges. Findings empirically demonstrate that flow is related to affect improvement during visual creativity. Affect change was linked to productivity and self-rated creativity, but no other objective or subjective performance measures. Flow was unrelated to all external performance measures but was highly correlated with self-rated creativity; flow may therefore motivate perseverance towards eventual excellence rather than provide direct cognitive enhancement.

  13. Intermittency in spiral Poiseuille flow

    Energy Technology Data Exchange (ETDEWEB)

    Heise, M; Abshagen, J; Menck, A; Pflster, G [Institute of Experimental and Applied Physics, University of Kiel, 24098 Kiel (Germany)

    2005-01-01

    The results of an experimental study on intermittent spiral vortices observed in a counter-rotating Taylor-Couette system with an additional axial through flow, i.e. Spiral-Poiseuille flow, are presented. Convectively unstable upstream propagating spiral vortices appear in the laminar basic flow from an oscillatory instability and in general become absolutely unstable at higher inner cylinder Reynolds number. It is found that at Reynolds numbers above the absolute stability border the spiral vortices become unstable and a complex flow state showing intermittent bursts appears. The intermittent flow state is characterised by an irregular alternation between clearly distinguishable 'laminar' phases corresponding to up-and downstream propagating spiral vortices as well as propagating Taylor vortices. For a sufficiently high rate of axial through flow it is found that intermittency can occur directly from the convectively unstable regime of the upstream propagating spiral vortices.

  14. 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.

  15. 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.

  16. Observation Predicates in Flow Logic

    DEFF Research Database (Denmark)

    Nielson, Flemming; Nielson, Hanne Riis; Sun, Hongyan

    2003-01-01

    Motivated by the connection between strong and soft type systems we explore flow analyses with hard constraints on the admissible solutions. We show how to use observation predicates and formula rearrangements to map flow analyses with hard constraints into more traditional flow analyses in such ......Motivated by the connection between strong and soft type systems we explore flow analyses with hard constraints on the admissible solutions. We show how to use observation predicates and formula rearrangements to map flow analyses with hard constraints into more traditional flow analyses...... in such a way that the hard constraints are satisfi ed exactly when the observation predicates report no violations. The development is carried out in a large fragment of a first order logic with negation and also takes care of the transformations necessary in order to adhere to the stratification restrictions...

  17. 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)

  18. DEBRIS FLOWS AND HYPERCONCENTRATED STREAMFLOWS.

    Science.gov (United States)

    Wieczorek, Gerald F.

    1986-01-01

    Examination of recent debris-flow and hyperconcentrated-streamflow events in the western United States reveals (1) the topographic, geologic, hydrologic, and vegetative conditions that affect initiation of debris flows and (2) the wide ranging climatic conditions that can trigger debris flows. Recognition of these physiographic and climatic conditions has aided development of preliminary methods for hazard evaluation. Recent developments in the application of electronic data gathering, transmitting, and processing systems shows potential for real-time hazard warning.

  19. Gross job flows and firms

    OpenAIRE

    Scott Schuh; Robert K. Triest

    1999-01-01

    This paper extends the work of Dunne, Roberts, and Samuelson [3] and Davis, Haltiwanger, and Schuh [2] on gross job flows among manufacturing plants. Gross job creation, destruction, and reallocation have been shown to be important in understanding the birth, growth, and death of plants, and the relation of plant life cycles to the business cycle. However, little is known about job flows between firms or how job flows among plants occur within firms (corporate restructuring). We use informati...

  20. Joseph Cornell's flow learning use

    OpenAIRE

    Lužnik, Anja

    2014-01-01

    Natural science is one of the subjects where nature or natural environment can often be used directly for teaching. Joseph Cornell, who introduced Flow Learning, also emphasises this fact. The main focus of my thesis was how Joseph Cornell’s Flow Learning could be used in our primary schools. I selected some learning objectives out of natural science and technology curriculum which could be achieved with the Flow Learning system using Cornell’s activities. I tested my thesis in practice w...

  1. Do European capital flows comove?

    OpenAIRE

    Silvio Contessi; Pierangelo DePace

    2008-01-01

    We study the cross-sectional correlations of net, total, and disaggregated capital flows for the major source and recipient European Union countries. We seek evidence of changes in these correlations since the introduction of the euro to understand whether the European Union can be considered a unique entity with regard to its international capital flows. We first use Ng's (2006) "uniform spacing" methodology to rank cross-sectional correlations (i.e., which flows comove more) and to shed lig...

  2. Confined vortices in flow machinery

    Science.gov (United States)

    Escudier, Marcel

    After noting such basic aspects of vortex flows as the concepts of supercritical and subcritical flow and vortex breakdown, swirling flow behavior in various practical devices is discussed. The devices in question encompass swirl-stabilized combustion in industrial combustion chambers, fluidic vortex amplifiers that may be used as large scale valves, turbomachine outlets that can efficiently divert axial throughflow in a tangential direction, 'cyclone' separators, turbine draft tube surge phenomena, and the Ranque-Hilsch refrigeration tube.

  3. 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.

  4. The Clinical Method and the Clinical Dilemmas.

    Directory of Open Access Journals (Sweden)

    Luis Alberto Corona Martinez

    2011-10-01

    Full Text Available The term ‘’clinic’’, among other meanings, refers to any information that suggests the presence of an illness and is obtained through questioning and physical examination processes that take place in the course of doctor-patient relationship. The purpose of this article is to summarize the challenges and dilemmas to be considered by students and young doctors in the patient's clinical approach, which completes the vision of the unquestionable positive role of clinical medical diagnosis. Different factors that can diminish the quality of obtained clinical information, thus interfering with the diagnostic process, have been classified into four groups: dependent on disease process, dependent on the individual patient or the source of information, dependent on the setting where information was obtained and dependent on the physician. As a generalization we state that the existence of the so-called challenges or dilemmas in clinical approach imply limitations to the clinical information obtained to be used with total reliability. Nevertheless, these dilemmas do not detract, nor even slightly, the values of clinical approach in the diagnostic process.

  5. Flow Cytometry in the Detection of Neonatal Sepsis

    Directory of Open Access Journals (Sweden)

    Volker N. Umlauf

    2013-01-01

    Full Text Available Neonatal sepsis remains a burden problem by showing minimal initial symptoms of subtle character, nonspecific manifestation, and diagnostic pitfalls. The clinical course can be fulminant and fatal if treatment is not commenced promptly. It is therefore crucial to establish early diagnosis and initiate adequate therapy. Besides clinical symptoms, the most reliable laboratory markers in establishing diagnosis is currently the combined measurement of CRP and a cytokine (IL-6 and IL-8. Due to their different kinetics, a diagnostic gap might occur and thus withholding antimicrobial therapy in clinical suspicion of infection is not acceptable. We therefore need parameters which unerringly differentiate between infants in need for antimicrobial therapy and those who are not. Flow cytometry promises to be a useful tool in this field, allowing the determination of different cellular, dissolved, and functional pathophysiological components of sepsis. Despite technical and methodical advances in flow cytometry, its use in clinical routine is still limited. Advantages and disadvantages of promising new parameters in diagnosis of sepsis performed by flow cytometry, particularly CD64, HLA-DR, and apoptosis, are reviewed here. The necessity of tests to be used as an “ideal” parameter is presented.

  6. 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

  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. 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.

  9. Surface obstacles in pulsatile flow

    Science.gov (United States)

    Carr, Ian A.; Plesniak, Michael W.

    2016-11-01

    Flows past obstacles mounted on flat surfaces have been widely studied due to their ubiquity in nature and engineering. For nearly all of these studies, the freestream flow over the obstacle was steady, i.e. constant velocity unidirectional flow. Unsteady, pulsatile flows occur frequently in biology, geophysics, biomedical engineering, etc. Our study is aimed at extending the comprehensive knowledge base that exists for steady flows to considerably more complex pulsatile flows. Beyond the important practical applications, characterizing the vortex and wake dynamics of flows around surface obstacles embedded in pulsatile flows can provide insights into the underlying physics in all wake and junction flows. In this study, we experimentally investigated the wake of four canonical surface obstacles: hemisphere, cube, and circular cylinders with aspect ratio of 1:1 and 2:1. Phase-averaged PIV and hot-wire anemometry are used to characterize the dynamics of coherent structures in the wake and at the windward junction of the obstacles. Complex physics occur during the deceleration phase of the pulsatile inflow. We propose a framework for understanding these physics based on self-induced vortex propagation, similar to the phenomena exhibited by vortex rings. This material is based in part upon work supported by the National Science Foundation under Grant Number CBET-1236351, and GW Centeor Biomimetics and Bioinspired Engineering (COBRE).

  10. Flow whitelisting in SCADA networks

    DEFF Research Database (Denmark)

    Barbosa, Rafael Ramos Regis; Sadre, Ramin; Pras, Aiko

    2013-01-01

    and the Internet. This paper describes an approach for improving the security of SCADA networks using flow whitelisting. A flow whitelist describes legitimate traffic based on four properties of network packets: client address, server address, server-side port and transport protocol. The proposed approach...... incorporates a learning phase in which a flow whitelist is learned by capturing network traffic over a period of time and aggregating it into flows. After the learning phase is complete, any non-whitelisted connection observed generates an alarm. The evaluation of the approach focuses on two important...

  11. Modeling Size Polydisperse Granular Flows

    Science.gov (United States)

    Lueptow, Richard M.; Schlick, Conor P.; Isner, Austin B.; Umbanhowar, Paul B.; Ottino, Julio M.

    2014-11-01

    Modeling size segregation of granular materials has important applications in many industrial processes and geophysical phenomena. We have developed a continuum model for granular multi- and polydisperse size segregation based on flow kinematics, which we obtain from discrete element method (DEM) simulations. The segregation depends on dimensionless control parameters that are functions of flow rate, particle sizes, collisional diffusion coefficient, shear rate, and flowing layer depth. To test the theoretical approach, we model segregation in tri-disperse quasi-2D heap flow and log-normally distributed polydisperse quasi-2D chute flow. In both cases, the segregated particle size distributions match results from full-scale DEM simulations and experiments. While the theory was applied to size segregation in steady quasi-2D flows here, the approach can be readily generalized to include additional drivers of segregation such as density and shape as well as other geometries where the flow field can be characterized including rotating tumbler flow and three-dimensional bounded heap flow. Funded by The Dow Chemical Company and NSF Grant CMMI-1000469.

  12. 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.

  13. Reactive particles in random flows.

    Science.gov (United States)

    Károlyi, György; Tél, Tamás; de Moura, Alessandro P S; Grebogi, Celso

    2004-04-30

    We study the dynamics of chemically or biologically active particles advected by open flows of chaotic time dependence, which can be modeled by a random time dependence of the parameters on a stroboscopic map. We develop a general theory for reactions in such random flows, and derive the reaction equation for this case. We show that there is a singular enhancement of the reaction in random flows, and this enhancement is increased as compared to the nonrandom case. We verify our theory in a model flow generated by four point vortices moving chaotically.

  14. 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.

  15. The AdaBoost Flow

    OpenAIRE

    Lykov, A.; Muzychka, S.; 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 that three algorithms of the AdaBoost family (i) the AdaBoost algorithm of Schapire and Freund (ii) the arc-gv algorithm of Breiman (iii) the confidence rated prediction of Schapire and Singer can be can be embedded in the AdaBoost flow. The nontrivial part of the AdaBoost flow equations coincides with the equations of dynamics of nonperiodic Toda system written in te...

  16. A Marine Traffic Flow Model

    Directory of Open Access Journals (Sweden)

    Tsz Leung Yip

    2013-03-01

    Full Text Available 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 one ship or two ships but does not address the issues in marine traffic flow.

  17. 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.

  18. 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

  19. A New Technology for Detecting Cerebral Blood Flow

    DEFF Research Database (Denmark)

    Schytz, Henrik W; Guo, Song; Jensen, Lars T;

    2012-01-01

    There is a need for real-time non-invasive, continuous monitoring of cerebral blood flow (CBF) during surgery, in intensive care units and clinical research. We investigated a new non-invasive hybrid technology employing ultrasound tagged near infrared spectroscopy (UT-NIRS) that may estimate...... changes in CBF using a cerebral blood flow index (CFI). Changes over time for UT-NIRS CFI and (133)Xenon single photon emission computer tomography ((133)Xe-SPECT) CBF data were assessed in 10 healthy volunteers after an intravenous bolus of acetazolamide. UT-NIRS CFI was measured continuously and SPECT...

  20. Synthetic Aperture Flow Imaging Using a Dual Beamformer Approach

    DEFF Research Database (Denmark)

    Li, Ye

    Color flow mapping systems have become widely used in clinical applications. It provides an opportunity to visualize the velocity profile over a large region in the vessel, which makes it possible to diagnose, e.g., occlusion of veins, heart valve deficiencies, and other hemodynamic problems....... However, while the conventional ultrasound imaging of making color flow mapping provides useful information in many circumstances, the spatial velocity resolution and frame rate are limited. The entire velocity distribution consists of image lines from different directions, and each image line...

  1. 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.

  2. 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

  3. Effect of flow fluctuations and nonflow on elliptic flow methods

    Energy Technology Data Exchange (ETDEWEB)

    Ollitrault, Jean-Yves; Poskanzer, Arthur M.; Voloshin, Sergei A.

    2009-04-16

    We discuss how the different estimates of elliptic flow are influenced by flow fluctuations and nonflow effects. It is explained why the event-plane method yields estimates between the two-particle correlation methods and the multiparticle correlation methods. It is argued that nonflow effects and fluctuations cannot be disentangled without other assumptions. However, we provide equations where, with reasonable assumptions about fluctuations and nonflow, all measured values of elliptic flow converge to a unique mean v_2,PP elliptic flow in the participant plane and, with a Gaussian assumption on eccentricity fluctuations, can be converted to the mean v_2,RP in the reaction plane. Thus, the 20percent spread in observed elliptic flow measurements from different analysis methods is no longer mysterious.

  4. Dynamics of electrochemical flows 1 Motion of electrochemical flows

    CERN Document Server

    Xu, Chengjun

    2013-01-01

    The motion of the electrolyte, comprising of solute ions and solvent molecules, is a frequently-occurring natural phenomenon. The motion of the electrolyte leads to the flows of ions and solvent molecules, known as electrochemical flows. In this study, we establish a general theory to describe the motion of the electrochemical flows. Our theory provides a different approach from others to clarify the details of the transport phenomena for the electrochemical flows. We derive the governing equations in the electrolyte fluid from mass, charge, momentum, energy, and concentration conservations. In addition, we normalize the governing equations to derive the dimensionless parameters, known as Reynolds, Thompson, Peclet, Prandtl and X numbers. The physical meaning of these parameter numbers in the electrochemical flow is discussed in detail. A new number, named X number, appears in the Navier-Stokes equation symbolizing the balance between the inertia force and the electric force.

  5. 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

  6. 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

  7. 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.

  8. 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.

  9. 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.

  10. The Clinical Assessment and Remote Administration Tablet

    Directory of Open Access Journals (Sweden)

    Jessica A Turner

    2011-12-01

    Full Text Available Electronic data capture of case report forms (CRFs, demographic, neuropsychiatric, or clinical assessments, can vary from scanning hand-written forms into databases to fully electronic systems. Web-based forms can be extremely useful for self-assessment; however, in the case of neuropsychiatric assessments, self-assessment is often not an option. The clinician often must be the person either summarizing or making their best judgment about the subject’s response in order to complete an assessment, and having the clinician turn away to type into a web browser may be disruptive to the flow of the interview. The Mind Research Network (MRN has developed a prototype for a software tool for the real-time acquisition and validation of clinical assessments in remote environments. We have developed the Clinical Assessment and Remote Administration Tablet (CARAT on a Microsoft Windows PC tablet system, which has been adapted to interact with various data models already in use in several large-scale databases of neuroimaging studies in clinical populations. The tablet has been used successfully to collect and administer clinical assessments in several large-scale studies, so that the correct clinical measures are integrated with the correct imaging and other data. It has proven to be incredibly valuable in confirming that data collection across multiple research groups is performed similarly, quickly, and with accountability for incomplete datasets. We present the overall architecture and an evaluation of its use.

  11. Tri-leaflet valve design with a purge flow for heart-assist devices: an in vitro optimization study.

    Science.gov (United States)

    Timmel, Tobias; Seshadri, Santhosh; Goubergrits, Leonid; Affeld, Klaus; Kertzscher, Ulrich

    2012-01-01

    The objective of this study is to assess the effect of a purge flow on valves of pulsatile heart-assist devices. Clinical applications of these devices are still limited because of frequent thromboembolic complications. These complications often originate at the valves and the unavoidable flow separation regions that are found behind the leaflets. The flow separations cause a long residence time of blood that is considered particularly detrimental. To solve this problem, a valve with a purge flow is proposed. A purge flow is a jet, which is separated from the main blood flow and directed behind the leaflets into the sinus to flush it. Even though the purge flow does not prevent a flow separation, it shortens the residence time of the blood in the sinus. Thus, the purge flow improves the periodic washout of the blood in the region of flow separation. The complex purge flow was investigated in a tri-leaflet valve. The geometrical parameters of the valve were varied systematically. A statistical technique--the Taguchi method--was used to reduce the number of investigated models to 12. The flows through the resulting valve models were numerically simulated and analyzed. The evaluated models with the best results were subsequently investigated experimentally using different methods: hemodynamic tests in a valve tester and flow visualization using the dye washout method. It was shown that the purge flow can effectively wash out the sinus. Therefore, the purge flow valve reduces the potential of a thrombus formation normally associated with the valve.

  12. Quantitative retinal blood flow mapping from fluorescein videoangiography using tracer kinetic modeling.

    Science.gov (United States)

    Tichauer, Kenneth M; Guthrie, Micah; Hones, Logan; Sinha, Lagnojita; St Lawrence, Keith; Kang-Mieler, Jennifer J

    2015-05-15

    Abnormal retinal blood flow (RBF) has been associated with numerous retinal pathologies, yet existing methods for measuring RBF predominantly provide only relative measures of blood flow and are unable to quantify volumetric blood flow, which could allow direct patient to patient comparison. This work presents a methodology based on linear systems theory and an image-based arterial input function to quantitatively map volumetric blood flow from standard fluorescein videoangiography data, and is therefore directly translatable to the clinic. Application of the approach to fluorescein retinal videoangiography in rats (4 control, 4 diabetic) demonstrated significantly higher RBF in 4-5 week diabetic rats as expected from the literature.

  13. 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.

  14. Stochastic power flow modeling

    Energy Technology Data Exchange (ETDEWEB)

    1980-06-01

    The stochastic nature of customer demand and equipment failure on large interconnected electric power networks has produced a keen interest in the accurate modeling and analysis of the effects of probabilistic behavior on steady state power system operation. The principle avenue of approach has been to obtain a solution to the steady state network flow equations which adhere both to Kirchhoff's Laws and probabilistic laws, using either combinatorial or functional approximation techniques. Clearly the need of the present is to develop sound techniques for producing meaningful data to serve as input. This research has addressed this end and serves to bridge the gap between electric demand modeling, equipment failure analysis, etc., and the area of algorithm development. Therefore, the scope of this work lies squarely on developing an efficient means of producing sensible input information in the form of probability distributions for the many types of solution algorithms that have been developed. Two major areas of development are described in detail: a decomposition of stochastic processes which gives hope of stationarity, ergodicity, and perhaps even normality; and a powerful surrogate probability approach using proportions of time which allows the calculation of joint events from one dimensional probability spaces.

  15. Bifunctional redox flow battery

    Energy Technology Data Exchange (ETDEWEB)

    Wen, Y.H. [Research Institute of Chemical Defense, Beijing 100083 (China)], E-mail: wen_yuehua@126.com; Cheng, J. [Research Institute of Chemical Defense, Beijing 100083 (China); Beijing Science and Technology University, Beijing 100083 (China); Xun, Y. [Research Institute of Chemical Defense, Beijing 100083 (China); Ma, P.H. [Full Cell R and D Center, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, Liaoning 116023 (China); Yang, Y.S. [Research Institute of Chemical Defense, Beijing 100083 (China); Beijing Science and Technology University, Beijing 100083 (China)

    2008-08-20

    A new bifunctional redox flow battery (BRFB) system, V(III)/V(II)-L-cystine(O{sub 2}), was systematically investigated by using different separators. It is shown that during charge, water transfer is significantly restricted with increasing the concentration of HBr when the Nafion 115 cation exchange membrane is employed. The same result can be obtained when the gas diffusion layer (GDL) hot-pressed separator is used. The organic electro-synthesis is directly correlated with the crossover of vanadium. When employing the anion exchange membrane, the electro-synthesis efficiency is over 96% due to a minimal crossover of vanadium. When the GDL hot-pressed separator is applied, the crossover of vanadium and water transfer are noticeably prevented and the electro-synthesis efficiency of over 99% is obtained. Those impurities such as vanadium ions and bromine can be eliminated through the purification of organic electro-synthesized products. The purified product is identified to be L-cysteic acid by IR spectrum. The BRFB shows a favorable discharge performance at a current density of 20 mA cm{sup -2}. Best discharge performance is achieved by using the GDL hot-pressed separator. The coulombic efficiency of 87% and energy efficiency of about 58% can be obtained. The cause of major energy losses is mainly associated with the cross-contamination of anodic and cathodic active electrolytes.

  16. 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.

  17. Laminar Flow Analysis

    Science.gov (United States)

    Rogers, David F.

    1992-10-01

    The major thrust of this book is to present a technique of analysis that aids the formulation, understanding, and solution of problems of viscous flow. The intent is to avoid providing a "canned" program to solve a problem, offering instead a way to recognize the underlying physical, mathematical, and modeling concepts inherent in the solutions. The reader must first choose a mathematical model and derive governing equations based on realistic assumptions, or become aware of the limitations and assumptions associated with existing models. An appropriate solution technique is then selected. The solution technique may be either analytical or numerical. Computer-aided analysis algorithms supplement the classical analyses. The book begins by deriving the Navier-Stokes equation for a viscous compressible variable property fluid. The second chapter considers exact solutions of the incompressible hydrodynamic boundary layer equations solved with and without mass transfer at the wall. Forced convection, free convection, and the compressible laminar boundary layer are discussed in the remaining chapters. The text unifies the various topics by tracing a logical progression from simple to complex governing differential equations and boundary conditions. Numerical, parametric, and directed analysis problems are included at the end of each chapter.

  18. 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.

  19. Controllability of flow turbulence.

    Science.gov (United States)

    Guan, Shuguang; Wei, G W; Lai, C-H

    2004-06-01

    In this paper, we study the controllability of real-world flow turbulence governed by the two-dimensional Navier-Stokes equations, using strategies developed in chaos control. A case of control/synchronization of turbulent dynamics is observed when only one component of the velocity field vector is unidirectionally coupled to a target state, while the other component is uncoupled. Unlike previous results, it is shown that the dynamics of the whole velocity field cannot be completely controlled/synchronized to the target, even in the limit of long time and strong coupling strength. It is further revealed that the controlled component of the velocity field can be fully controlled/synchronized to the target, but the other component, which is not directly coupled to the target, can only be partially controlled/synchronized to the target. By extending an auxiliary method to distributed dynamic systems, the partial synchronization of two turbulent orbits in the present study can be categorized in the domain of generalized synchronization of spatiotemporal dynamics.

  20. 导流杂交法检测宫颈病变中人乳头瘤病毒的基因型及其感染的临床意义%Clinical Significance of the Detection of Human Papilloma Virus Genotype and Infection in Cervical Lesions With Flow-through Hybridization

    Institute of Scientific and Technical Information of China (English)

    贺婵娟; 姚德生; 卢艳

    2012-01-01

    Objective To detect human papilloma virus( HPV ) genotype and infection in cervical lesions with flow-through hybridization( HybriMax ), and to explore its clinical significance. Methods Two hundred and ninety-six patients with cervical cancer who were detected with HybriMax were divided into normal histological manifestation group ( 58 cases ),chronic cervicitis group( 32 cases ),cervical intraepithelial neoplasia group[ 21 cases of cervical intraepithelial neoplasiaC ON )I,19 cases of CIN 11,26 cases of ON III ] and cervical cancer group( 140 cases ). The positive rates of HPV infection were compared among five groups. Results There were 191 cases infected with HPV among 296 cases ,the positive rate of HPV was 64.53% ;The positive rate was 18.97%( 11/58 ) in normal histological manifestation group,25%( 8/32 ) in chronic cervicitis group,28.57%( 6/21 ) in ON I group,73. 68%( 14/19 ) in ON E group,88.46%( 23/26 ) in ON HI group,92. 14%( 129/140 ) in cervical cancer group, there was no statistical significance among normal histological manifestation group, chronic cervicitis group and CIN I group( P > 0. 05 ), the positive rate of HPV was lower in normal histological manifestation group than in CIN II group, CIN HI group, cervical cancer group( P < 0. 05 ). The positive rate of HPV increased with the severity of cervical lesion( P < 0. 05 ). The six most common genotypes in cervical lesion patients with high infection rate were:type 16,18,58,52,53,33,with the positive rate of 35. 47% ( 105/296 ),10.47%( 31/296 ),6.42%( 19/296 ),5.41%( 16/296 ),3.04%( 9/296 ),2.70%( 8/296 ),respectively. Conclusion Cervical lesion is closely related with HPV infection,and high-oncogenic risk HPV infection is an important factor of cervical cancer. HybriMax has important significance for the screening,treatment,and follow-up of ON and cervical cancer.%目的 应用导流杂交基因芯片技术(HybriMax)检测宫颈病变人乳头瘤病毒(HPV)基因型及其感染情况,

  1. 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.

  2. 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.

  3. Mathematical Modeling of Electrolyte Flow Dynamic Patterns and Volumetric Flow Penetrations in the Flow Channel over Porous Electrode Layered System in Vanadium Flow Battery with Serpentine Flow Field Design

    CERN Document Server

    Ke, Xinyou; Alexander, J Iwan D; Savinell, Robert F

    2016-01-01

    In this work, a two-dimensional mathematical model is developed to study the flow patterns and volumetric flow penetrations in the flow channel over the porous electrode layered system in vanadium flow battery with serpentine flow field design. The flow distributions at the interface between the flow channel and porous electrode are examined. It is found that the non-linear pressure distributions can distinguish the interface flow distributions under the ideal plug flow and ideal parabolic flow inlet boundary conditions. However, the volumetric flow penetration within the porous electrode beneath the flow channel through the integration of interface flow velocity reveals that this value is identical under both ideal plug flow and ideal parabolic flow inlet boundary conditions. The volumetric flow penetrations under the advection effects of flow channel and landing/rib are estimated. The maximum current density achieved in the flow battery can be predicted based on the 100% amount of electrolyte flow reactant ...

  4. 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

  5. Redox Flow Batteries, a Review

    Energy Technology Data Exchange (ETDEWEB)

    Knoxville, U. Tennessee; U. Texas Austin; U, McGill; Weber, Adam Z.; Mench, Matthew M.; Meyers, Jeremy P.; Ross, Philip N.; Gostick, Jeffrey T.; Liu, Qinghua

    2011-07-15

    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.

  6. Highly deformable nanofilaments in flow

    Science.gov (United States)

    Pawłowska, S.

    2016-10-01

    Experimental analysis of hydrogel nanofilaments conveyed by flow is conducted to help in understanding physical phenomena responsible for transport properties and shape deformations of long bio-objects, like DNA or proteins. Investigated hydrogel nanofilaments exhibit typical macromolecules-like behavior, as spontaneous conformational changes and cross-flow migration. Results of the experiments indicate critical role of thermal fluctuations behavior of single filaments.

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. 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…

  12. Apparatus for measuring fluid flow

    Science.gov (United States)

    Smith, J.E.; Thomas, D.G.

    Flow measuring apparatus includes a support loop having strain gages mounted thereon and a drag means which is attached to one end of the support loop and which bends the sides of the support loop and induces strains in the strain gages when a flow stream impacts thereon.

  13. Techniques for evaluating cash flow.

    Science.gov (United States)

    Sylvestre, J; Urbancic, F

    1994-01-01

    Jean Sylvestre, Ph.D., and Frank Urbancic, D.B.A., CPA, of the University of South Alabama, write that because of the financial challenges for health care, cash flow problems can arise. They offer techniques for interpreting and evaluating cash flow information as a means to more effective decision making.

  14. Multiphase flow wax deposition modelling

    Energy Technology Data Exchange (ETDEWEB)

    Matzain, A. [Petronas Research and Scientific Services, Kuala Lumpur (Malaysia); Zhang, H.-Q.; Volk, M.; Redus, C.L.; Brill, J.P. [University of Tulsa (United States); Apte, M.S. [Shell Technology EP (United States); Creek, J.L. [Chevron Petroleum Technology (United States)

    2000-07-01

    Results are presented from two-phase flow wax deposition tests using a state-of-the-art, high pressure, multiphase flow test facility. Wax deposition was found to be flow pattern dependent and occurs only along the pipe wall in contact with the waxy crude oil. The deposition buildup trend at low mixture velocities is similar to that observed in laminar single-phase flow tests. The buildup trend at high mixture velocities is similar to that observed in turbulent single-phase flow tests. Thinner and harder deposits at the bottom than at the top of the pipe were observed in horizontal intermittent flow tests. Thicker and harder deposits were observed at low liquid superficial velocity than at high liquid superficial velocity annular flow tests. No wax deposition was observed along the upper portion of the pipe in stratified flow tests. A semi-empirical kinetic model tailored for the wax deposition tests predicted wax thickness with an acceptable accuracy, especially at high oil superficial velocity. Deposition rate reduction due to shear stripping and rate enhancement due to entrapment of oil and other mechanisms not accounted for by the classical Fick's mass diffusion theory were incorporated through the use of dimensionless variables and empirical constants derived from the wax deposition data. The kinetic model, although semi-empirical, provides an insight for future model development. (author)

  15. Numerical methods for turbulent flow

    Science.gov (United States)

    Turner, James C., Jr.

    1988-01-01

    It has generally become accepted that the Navier-Strokes equations predict the dynamic behavior of turbulent as well as laminar flows of a fluid at a point in space away form a discontinuity such as a shock wave. Turbulence is also closely related to the phenomena of non-uniqueness of solutions of the Navier-Strokes equations. These second order, nonlinear partial differential equations can be solved analytically for only a few simple flows. Turbulent flow fields are much to complex to lend themselves to these few analytical methods. Numerical methods, therefore, offer the only possibility of achieving a solution of turbulent flow equations. In spite of recent advances in computer technology, the direct solution, by discrete methods, of the Navier-Strokes equations for turbulent flow fields is today, and in the foreseeable future, impossible. Thus the only economically feasible way to solve practical turbulent flow problems numerically is to use statistically averaged equations governing mean-flow quantities. The objective is to study some recent developments relating to the use of numerical methods to study turbulent flow.

  16. Prandtl-Batchelor flows revisited

    NARCIS (Netherlands)

    Wijngaarden, van L.

    2007-01-01

    In this paper laminar flows are considered with closed streamlines. For such flows Prandtl [1905. Űber Flüssigkeitsbewegung bei sehr kleiner Reibung. Verhandlungen des III. Internationalen Mathematiker Kongresses, Heidelberg, 1904, pp. 484-491, Teubner, Leizig. See Gesammelte Abhandlungen II, pp.

  17. 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.

  18. UZ Flow Models and Submodels

    Energy Technology Data Exchange (ETDEWEB)

    Y. Wu

    2004-11-01

    The purpose of this report is to document the unsaturated zone (UZ) flow models and submodels, as well as the flow fields that have been generated using the UZ flow model(s) of Yucca Mountain, Nevada. In this report, the term ''UZ model'' refers to the UZ flow model and the several submodels, which include tracer transport, temperature or ambient geothermal, pneumatic or gas flow, and geochemistry (chloride, calcite, and strontium) submodels. The term UZ flow model refers to the three-dimensional models used for calibration and simulation of UZ flow fields. This work was planned in the ''Technical Work Plan (TWP) for: Unsaturated Zone Flow Analysis and Model Report Integration'' (BSC 2004 [DIRS 169654], Section 1.2.7). The table of included Features, Events, and Processes (FEPs), Table 6.2-11, is different from the list of included FEPs assigned to this report in the ''Technical Work Plan for: Unsaturated Zone Flow Analysis and Model Report Integration'' (BSC 2004 [DIRS 169654], Table 2.1.5-1), as discussed in Section 6.2.6. The UZ model has revised, updated, and enhanced the previous UZ model (BSC 2001 [DIRS 158726]) by incorporating the 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 three-dimensional UZ flow fields are used directly by Total System Performance Assessment (TSPA). 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 hypotheses of flow and transport at different scales, and predict flow and transport behavior under a variety of climatic conditions. In addition, the limitations of the UZ model are discussed in Section 8.11.

  19. 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

  20. Flow Over a Model Submarine

    Science.gov (United States)

    Jiménez, Juan; Smits, Alexander

    2003-11-01

    Experimental investigation over a DARPA SUBOFF submarine model (SUBOFF Model) was performed using flow visualization and Digital Particle Image Velocimetry (DPIV). The model has an axisymmetric body with sail and fins, and it was supported by a streamlined strut that was formed by the extension of the sail appendage. The range of flow conditions studied correspond to a Reynolds numbers based on model length, Re_L, of about 10^5. Velocity vector fields, turbulence intensities, vorticity fields, and flow visualization in the vicinity of the junction flows are presented. In the vicinity of the control surface and sail hull junctions, the presence of streamwise vortices in the form of horseshoe or necklace vortices locally dominates the flow. The effects of unsteady motions about an axis passing through the sail are also investigated to understand the evolution of the unsteady wake.

  1. Quantifying global international migration flows.

    Science.gov (United States)

    Abel, Guy J; Sander, Nikola

    2014-03-28

    Widely available data on the number of people living outside of their country of birth do not adequately capture contemporary intensities and patterns of global migration flows. We present data on bilateral flows between 196 countries from 1990 through 2010 that provide a comprehensive view of international migration flows. Our data suggest a stable intensity of global 5-year migration flows at ~0.6% of world population since 1995. In addition, the results aid the interpretation of trends and patterns of migration flows to and from individual countries by placing them in a regional or global context. We estimate the largest movements to occur between South and West Asia, from Latin to North America, and within Africa.

  2. Fractal Structure of Debris Flow

    Institute of Scientific and Technical Information of China (English)

    LI Yong; LIU Jingjing; HU Kaiheng; CHEN Xiaoqing

    2007-01-01

    One of the most remarkable characteristics of debris flow is the competence for supporting boulders on the surface of flow, which strongly suggests that there should be some structure in the fluid body. This paper analyzed the grain compositions from various samples of debris flows and then revealed the fractal structure. Specifically, the fractality holds in three domains that can be respectively identified as the slurry, matrix, and the coarse content. Furthermore, the matrix fractal, which distinguishes debris flow from other kinds of flows, involves a hierarchical structure in the sense that it might contain ever increasing grains while the total range of grain size increases. It provides a possible mechanism for the boulder suspension.

  3. Flowing dusty plasma experiments: generation of flow and measurement techniques

    Science.gov (United States)

    Jaiswal, S.; Bandyopadhyay, P.; Sen, A.

    2016-12-01

    A variety of experimental techniques for the generation of subsonic/supersonic dust fluid flows and means of measuring such flow velocities are presented. The experiments have been carried out in a \\Pi -shaped dusty plasma experimental device with micron size kaolin/melamine formaldehyde particles embedded in a background of argon plasma created by a direct current glow discharge. A stationary dust cloud is formed over the cathode region by precisely balancing the pumping speed and gas flow rate. A flow of dust particles/fluid is generated by additional gas injection from a single or dual locations or by altering the dust confining potential. The flow velocity is then estimated by three different techniques, namely, by super particle identification code, particle image velocimetry analysis and the excitation of dust acoustic waves. The results obtained from these three different techniques along with their merits and demerits are discussed. An estimation of the neutral drag force responsible for the generation as well as the attenuation of the dust fluid flow is made. These techniques can be usefully employed in laboratory devices to investigate linear and non-linear collective excitations in a flowing dusty plasma.

  4. Recurrent flow analysis in spatiotemporally chaotic 2-dimensional Kolmogorov flow

    Energy Technology Data Exchange (ETDEWEB)

    Lucas, Dan, E-mail: dan.lucas@ucd.ie; Kerswell, Rich R., E-mail: r.r.kerswell@bris.ac.uk [School of Mathematics, University of Bristol, University Walk, Bristol (United Kingdom)

    2015-04-15

    Motivated by recent success in the dynamical systems approach to transitional flow, we study the efficiency and effectiveness of extracting simple invariant sets (recurrent flows) directly from chaotic/turbulent flows and the potential of these sets for providing predictions of certain statistics of the flow. Two-dimensional Kolmogorov flow (the 2D Navier-Stokes equations with a sinusoidal body force) is studied both over a square [0, 2π]{sup 2} torus and a rectangular torus extended in the forcing direction. In the former case, an order of magnitude more recurrent flows are found than previously [G. J. Chandler and R. R. Kerswell, “Invariant recurrent solutions embedded in a turbulent two-dimensional Kolmogorov flow,” J. Fluid Mech. 722, 554–595 (2013)] and shown to give improved predictions for the dissipation and energy pdfs of the chaos via periodic orbit theory. Analysis of the recurrent flows shows that the energy is largely trapped in the smallest wavenumbers through a combination of the inverse cascade process and a feature of the advective nonlinearity in 2D. Over the extended torus at low forcing amplitudes, some extracted states mimic the statistics of the spatially localised chaos present surprisingly well recalling the findings of Kawahara and Kida [“Periodic motion embedded in plane Couette turbulence: Regeneration cycle and burst,” J. Fluid Mech. 449, 291 (2001)] in low-Reynolds-number plane Couette flow. At higher forcing amplitudes, however, success is limited highlighting the increased dimensionality of the chaos and the need for larger data sets. Algorithmic developments to improve the extraction procedure are discussed.

  5. Measurement of flow in supercritical flow regime using cutthroat flumes

    Indian Academy of Sciences (India)

    Shrikant A Tekade; Avinash D Vasudeo; Aniruddha D Ghare; Ramesh N Ingle

    2016-02-01

    Cutthroat flume is commonly used for measurement of subcritical flow in open channel because of its simplicity and ease of construction. No experimental data is available in literature for measurement of flow in supercritical regime using cutthroat flume. The present paper finds the feasibility of cutthroat flume as a measurement device for flow in supercritical regime. Experimental data are generated to develop the relation between discharge and observed head at a specified location on upstream of throat section. Regression analysis for discharge and head indicated a good correlation. Based on all the experimental data generated, a relationship between discharge and head is proposed.

  6. Flow accelerated organic coating degradation

    Science.gov (United States)

    Zhou, Qixin

    Applying organic coatings is a common and the most cost effective way to protect metallic objects and structures from corrosion. Water entry into coating-metal interface is usually the main cause for the deterioration of organic coatings, which leads to coating delamination and underfilm corrosion. Recently, flowing fluids over sample surface have received attention due to their capability to accelerate material degradation. A plethora of works has focused on the flow induced metal corrosion, while few studies have investigated the flow accelerated organic coating degradation. Flowing fluids above coating surface affect corrosion by enhancing the water transport and abrading the surface due to fluid shear. Hence, it is of great importance to understand the influence of flowing fluids on the degradation of corrosion protective organic coatings. In this study, a pigmented marine coating and several clear coatings were exposed to the laminar flow and stationary immersion. The laminar flow was pressure driven and confined in a flow channel. A 3.5 wt% sodium chloride solution and pure water was employed as the working fluid with a variety of flow rates. The corrosion protective properties of organic coatings were monitored inline by Electrochemical Impedance Spectroscopy (EIS) measurement. Equivalent circuit models were employed to interpret the EIS spectra. The time evolution of coating resistance and capacitance obtained from the model was studied to demonstrate the coating degradation. Thickness, gloss, and other topography characterizations were conducted to facilitate the assessment of the corrosion. The working fluids were characterized by Fourier Transform Infrared Spectrometer (FTIR) and conductivity measurement. The influence of flow rate, fluid shear, fluid composition, and other effects in the coating degradation were investigated. We conclude that flowing fluid on the coating surface accelerates the transport of water, oxygen, and ions into the coating, as

  7. Effect of air-flow on the evaluation of refractive surgery ablation patterns.

    Science.gov (United States)

    Dorronsoro, Carlos; Schumacher, Silvia; Pérez-Merino, Pablo; Siegel, Jan; Mrochen, Michael; Marcos, Susana

    2011-02-28

    An Allegretto Eye-Q laser platform (Wavelight GmbH, Erlangen, Germany) was used to study the effect of air-flow speed on the ablation of artificial polymer corneas used for testing refractive surgery patterns. Flat samples of two materials (PMMA and Filofocon A) were ablated at four different air flow conditions. The shape and profile of the ablated surfaces were measured with a precise non-contact optical surface profilometer. Significant asymmetries in the measured profiles were found when the ablation was performed with the clinical air aspiration system, and also without air flow. Increasing air-flow produced deeper ablations, improved symmetry, and increased the repeatability of the ablation pattern. Shielding of the laser pulse by the plume of smoke during the ablation of plastic samples reduced the central ablation depth by more than 40% with no-air flow, 30% with clinical air aspiration, and 5% with 1.15 m/s air flow. A simple model based on non-inertial dragging of the particles by air flow predicts no central shielding with 2.3 m/s air flow, and accurately predicts (within 2 μm) the decrease of central ablation depth by shielding. The shielding effects for PMMA and Filofocon A were similar despite the differences in the ablation properties of the materials and the different full-shielding transmission coefficient, which is related to the number of particles ejected and their associated optical behavior. Air flow is a key factor in the evaluation of ablation patterns in refractive surgery using plastic models, as significant shielding effects are found with typical air-flow levels used under clinical conditions. Shielding effects can be avoided by tuning the air flow to the laser repetition rate.

  8. Transformation of Commercial Flows into Physical Flows of Electricity – Flow Based Method

    Directory of Open Access Journals (Sweden)

    M. Adamec

    2009-01-01

    Full Text Available We are witnesses of large – scale electricity transport between European countries under the umbrella of the UCTE organization. This is due to the inabilyof generators to satisfy the growing consumption in some regions. In this content, we distinguish between two types of flow. The first type is physical flow, which causes costs in the transmission grid, whilst the second type is commercial flow, which provides revenues for the market participants. The old methods for allocating transfer capacity fail to take this duality into account. The old methods that allocate transmission border capacity to “virtual” commercial flows which, in fact, will not flow over this border, do not lead to optimal allocation. Some flows are uselessly rejected and conversely, some accepted flows can cause congestion on another border. The Flow Based Allocation method (FBA is a method which aims to solve this problem.Another goal of FBA is to ensure sustainable development of expansion of transmission capacity. Transmission capacity is important, because it represents a way to establish better transmission system stability, and it provides a distribution channel for electricity to customers abroad. For optimal development, it is necessary to ensure the right division of revenue allocation among the market participants.This paper contains a brief description of the FBA method. Problems of revenue maximization and optimal revenue distribution are mentioned. 

  9. Flow analysis of the ophthalmic artery

    Energy Technology Data Exchange (ETDEWEB)

    Harada, Kuniaki; Hashimoto, Masato; Bandoh, Michio; Odawara, Yoshihiro; Kamagata, Masaki; Shirase, Ryuji [Sapporo Medical Univ. (Japan). Hospital

    2003-02-01

    The purpose of this study was to analyze the hemodynamics of ophthalmic artery flow using phase contrast MR angiography (PC-MRA). A total of 14 eyes from 10 normal volunteers and a patient with normal tension glaucoma (NTG) were analyzed. The optimal conditions were time repetition (TR)/echo time (TE)/flip angle (FA)/nex=40 ms/minimum/90 deg/2, field of view (FOV)=6 cm, matrix size=256 x 256. The resistive index (RI) and pulsatillity index (PI) values were significantly raised in the patient with NTG when compared to the control group. We therefore believe that PC-MRA may be a useful clinical tool for the assessment of the mechanism of NTG. (author)

  10. The 'Sphere': A Dedicated Bifurcation Aneurysm Flow-Diverter Device.

    Science.gov (United States)

    Peach, Thomas; Cornhill, J Frederick; Nguyen, Anh; Riina, Howard; Ventikos, Yiannis

    2014-01-01

    We present flow-based results from the early stage design cycle, based on computational modeling, of a prototype flow-diverter device, known as the 'Sphere', intended to treat bifurcation aneurysms of the cerebral vasculature. The device is available in a range of diameters and geometries and is constructed from a single loop of NITINOL(®) wire. The 'Sphere' reduces aneurysm inflow by means of a high-density, patterned, elliptical surface that partially occludes the aneurysm neck. The device is secured in the healthy parent vessel by two armatures in the shape of open loops, resulting in negligible disruption of parent or daughter vessel flow. The device is virtually deployed in six anatomically accurate bifurcation aneurysms: three located at the Basilar tip and three located at the terminus bifurcation of the Internal Carotid artery (at the meeting of the middle cerebral and anterior cerebral arteries). Both steady state and transient flow simulations reveal that the device presents with a range of aneurysm inflow reductions, with mean flow reductions falling in the range of 30.6-71.8% across the different geometries. A significant difference is noted between steady state and transient simulations in one geometry, where a zone of flow recirculation is not captured in the steady state simulation. Across all six aneurysms, the device reduces the WSS magnitude within the aneurysm sac, resulting in a hemodynamic environment closer to that of a healthy vessel. We conclude from extensive CFD analysis that the 'Sphere' device offers very significant levels of flow reduction in a number of anatomically accurate aneurysm sizes and locations, with many advantages compared to current clinical cylindrical flow-diverter designs. Analysis of the device's mechanical properties and deployability will follow in future publications.

  11. 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

  12. The physics of debris flows

    Science.gov (United States)

    Iverson, R.M.

    1997-01-01

    Recent advances in theory and experimentation motivate a thorough reassessment of the physics of debris flows. Analyses of flows of dry, granular solids and solid-fluid mixtures provide a foundation for a comprehensive debris flow theory, and experiments provide data that reveal the strengths and limitations of theoretical models. Both debris flow materials and dry granular materials can sustain shear stresses while remaining static; both can deform in a slow, tranquil mode characterized by enduring, frictional grain contacts; and both can flow in a more rapid, agitated mode characterized by brief, inelastic grain collisions. In debris flows, however, pore fluid that is highly viscous and nearly incompressible, composed of water with suspended silt and clay, can strongly mediate intergranular friction and collisions. Grain friction, grain collisions, and viscous fluid flow may transfer significant momentum simultaneously. Both the vibrational kinetic energy of solid grains (measured by a quantity termed the granular temperature) and the pressure of the intervening pore fluid facilitate motion of grains past one another, thereby enhancing debris flow mobility. Granular temperature arises from conversion of flow translational energy to grain vibrational energy, a process that depends on shear rates, grain properties, boundary conditions, and the ambient fluid viscosity and pressure. Pore fluid pressures that exceed static equilibrium pressures result from local or global debris contraction. Like larger, natural debris flows, experimental debris flows of ???10 m3 of poorly sorted, water-saturated sediment invariably move as an unsteady surge or series of surges. Measurements at the base of experimental flows show that coarse-grained surge fronts have little or no pore fluid pressure. In contrast, finer-grained, thoroughly saturated debris behind surge fronts is nearly liquefied by high pore pressure, which persists owing to the great compressibility and moderate

  13. Analysis of Secondary Flows in Centrifugal Impellers

    Directory of Open Access Journals (Sweden)

    Brun Klaus

    2005-01-01

    Full Text Available Secondary flows are undesirable in centrifugal compressors as they are a direct cause for flow (head losses, create nonuniform meridional flow profiles, potentially induce flow separation/stall, and contribute to impeller flow slip; that is, secondary flows negatively affect the compressor performance. A model based on the vorticity equation for a rotating system was developed to determine the streamwise vorticity from the normal and binormal vorticity components (which are known from the meridional flow profile. Using the streamwise vorticity results and the small shear-large disturbance flow method, the onset, direction, and magnitude of circulatory secondary flows in a shrouded centrifugal impeller can be predicted. This model is also used to estimate head losses due to secondary flows in a centrifugal flow impeller. The described method can be employed early in the design process to develop impeller flow shapes that intrinsically reduce secondary flows rather than using disruptive elements such as splitter vanes to accomplish this task.

  14. Quantitative blood flow velocity imaging using laser speckle flowmetry

    Science.gov (United States)

    Nadort, Annemarie; Kalkman, Koen; van Leeuwen, Ton G.; Faber, Dirk J.

    2016-04-01

    Laser speckle flowmetry suffers from a debated quantification of the inverse relation between decorrelation time (τc) and blood flow velocity (V), i.e. 1/τc = αV. Using a modified microcirculation imager (integrated sidestream dark field - laser speckle contrast imaging [SDF-LSCI]), we experimentally investigate on the influence of the optical properties of scatterers on α in vitro and in vivo. We found a good agreement to theoretical predictions within certain limits for scatterer size and multiple scattering. We present a practical model-based scaling factor to correct for multiple scattering in microcirculatory vessels. Our results show that SDF-LSCI offers a quantitative measure of flow velocity in addition to vessel morphology, enabling the quantification of the clinically relevant blood flow, velocity and tissue perfusion.

  15. Transmural myocardial ischemia due to slow coronary flow

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Slow coronary flow phenomenon(SCFP) is an angiographic observation characterized by delayed distal vessel opacification in the absence of significant epicardial coronary disease. Only limited studies have been focused on the etiologies, clinical manifestations and treatment of this unique angiographic phenomenon. In our case report, we described an 85-year-old man who came with significant ST segment elevation in leads V1-V4 and V3R-V5R without increase in myocardial enzyme. The patient also developed respiratory failure requiring intubation and mechanical ventilation. Coronary angiography revealed only mild atherosclerosis without spasm or thromboembolic occlusion. Slow flow was seen in all coronary arteries, especially in the left anterior descending and right coronary arteries. This case speculated that transmural myocardial ischemia with ST segment elevation might be resulted from slow coronary flow. Transmural myocardial ischemia can occur owing to abnormalities of the coronary microcirculation.

  16. Low flow veno-venous ECMO: an experimental study.

    Science.gov (United States)

    Calderón, M; Verdín, R; Galván, J; Gonzalez, M; Cárdenas, H; Campos, R; Vidrio, H; Amezcua, J

    1994-01-01

    Clinical use of extracorporeal membrane oxygenation (ECMO) and carbon dioxide removal (ECCO 2R) have become well established techniques for the treatment of severe respiratory failure; however they require full cardiopulmonary bypass, representing major procedures with high morbidity. We theorized the possibility of an efficient low flow veno-venous extracorporeal membrane gas exchange method. Four mongrel 12 kg dogs were submitted to veno-venous extracorporeal membrane gas exchange via a jugular dialysis catheter using a low flow (10 ml/min) roller pump and a membrane oxygenator for a period of four hours. Respiratory rate was set at 4 breaths/min with a FiO 2 of 21% and ventilatory dead space was increased. Adequate gas exchange was obtained (pO 2139, pCO 224, Sat 99.4%), without major hemodynamic changes or hematuria. Our results demonstrate the feasibility of a low flow, less aggressive system. Further research should be considered.

  17. 4D Flow of the Whole Heart and Great Vessels Using a Real Time Self Respiratory Gating Technique

    DEFF Research Database (Denmark)

    Uribe, Sergio; Beerbaum, Philipp; Sørensen, Thomas Sangild

    To evaluate the feasibility of a 4D-flow sequence of the whole heart and great vessel to retrospectively quantify blood flow within the entire heart. 4D-flow has been introduced as a means of acquiring anatomical and three-directional velocity information for all pixels within a 3D volume over...... for the acquisition of 4D-flow data of an isotropic saggital volume using a real time self gating technique. The data can thereafter be reformatted in any clinical view allowing the quantification of flow in different vessels with arbitrary orientations. This is important in congenital heart (CH) patients where scan...

  18. Boiling flow through diverging microchannel

    Indian Academy of Sciences (India)

    V S Duryodhan; S G Singh; Amit Agrawal

    2013-12-01

    An experimental study of flow boiling through diverging microchannel has been carried out in this work, with the aim of understanding boiling in nonuniform cross-section microchannel. Diverging microchannel of 4° of divergence angle and 146 m hydraulic diameter (calculated at mid-length) has been employed for the present study with deionised water as working fluid. Effect of mass flux (118–1182 kg/m2-s) and heat flux (1.6–19.2 W/cm2) on single and two-phase pressure drop and average heat transfer coefficient has been studied. Concurrently, flow visualization is carried out to document the various flow regimes and to correlate the pressure drop and average heat transfer coefficient to the underlying flow regime. Four flow regimes have been identified from the measurements: bubbly, slug, slug–annular and periodic dry-out/rewetting. Variation of pressure drop with heat flux shows one maxima which corresponds to transition from bubbly to slug flow. It is shown that significantly large heat transfer coefficient (up to 107 kW/m2-K) can be attained for such systems, for small pressure drop penalty and with good flow stability.

  19. Forced hyperbolic mean curvature flow

    CERN Document Server

    Mao, Jing

    2012-01-01

    In this paper, we investigate two hyperbolic flows obtained by adding forcing terms in direction of the position vector to the hyperbolic mean curvature flows in \\cite{klw,hdl}. For the first hyperbolic flow, as in \\cite{klw}, by using support function, we reduce it to a hyperbolic Monge-Amp$\\grave{\\rm{e}}$re equation successfully, leading to the short-time existence of the flow by the standard theory of hyperbolic partial differential equation. If the initial velocity is non-negative and the coefficient function of the forcing term is non-positive, we also show that there exists a class of initial velocities such that the solution of the flow exists only on a finite time interval $[0,T_{max})$, and the solution converges to a point or shocks and other propagating discontinuities are generated when $t\\rightarrow{T_{max}}$. These generalize the corresponding results in \\cite{klw}. For the second hyperbolic flow, as in \\cite{hdl}, we can prove the system of partial differential equations related to the flow is ...

  20. Hydroplaning and submarine debris flows

    Science.gov (United States)

    de Blasio, Fabio V.; Engvik, Lars; Harbitz, Carl B.; ElverhøI, Anders

    2004-01-01

    Examination of submarine clastic deposits along the continental margins reveals the remnants of holocenic or older debris flows with run-out distances up to hundreds of kilometers. Laboratory experiments on subaqueous debris flows, where typically one tenth of a cubic meter of material is dropped down a flume, also show high velocities and long run-out distances compared to subaerial debris flows. Moreover, they show the tendency of the head of the flow to run out ahead of the rest of the body. The experiments reveal the possible clue to the mechanism of long run-out. This mechanism, called hydroplaning, begins as the dynamic pressure at the front of the debris flow becomes of the order of the pressure exerted by the weight of the sediment. In such conditions a layer of water can intrude under the sediment with a lubrication effect and a decrease in the resistance forces between the sediment and the seabed. A physical-mathematical model of hydroplaning is presented and investigated numerically. The model is applied to both laboratory- and field-scale debris flows. Agreement with laboratory experiments makes us confident in the extrapolation of our model to natural flows and shows that long run-out distances can be naturally attained.

  1. Simulation of Multistage Turbine Flows

    Science.gov (United States)

    Celestina, M. L.; Mulac, R. A.; Adamczyk, J. J.

    1985-01-01

    The numerical simulation of turbine flows serves to enhance the understanding of the flow phenomena within multistage turbomachinery components. The direct benefit of this activity is improved modeling capability, which can be used to improve component efficiency and durability. A hierarchy of equations was formulated to assess the difficulty in analyzing the flow field within multistage turbomachinery components. The Navier-Stokes equations provides the most complete description. The simplest description is given by a set of equations that govern the quasi-one-dimensional flow. The number of unknowns to be solved for increases monotonically above the number of equations. The development of the additional set of equations needed to mathematically close the system of equations forms the closure problem associated with that level of description. For the Navier-Stokes equation there is no closure problem. For the quasi-one-dimensional equation set random flow fluctuations, unsteady fluctuations, nonaxisymmetric flow variations, and hub-to-shroud variations on the quasi-one-dimensional flow must be accounted for.

  2. Two-Photon Flow Cytometry

    Science.gov (United States)

    Zhog, Cheng Frank; Ye, Jing Yong; Norris, Theodore B.; Myc, Andrzej; Cao, Zhengyl; Bielinska, Anna; Thomas, Thommey; Baker, James R., Jr.

    2004-01-01

    Flow cytometry is a powerful technique for obtaining quantitative information from fluorescence in cells. Quantitation is achieved by assuring a high degree of uniformity in the optical excitation and detection, generally by using a highly controlled flow such as is obtained via hydrodynamic focusing. In this work, we demonstrate a two-beam, two- channel detection and two-photon excitation flow cytometry (T(sup 3)FC) system that enables multi-dye analysis to be performed very simply, with greatly relaxed requirements on the fluid flow. Two-photon excitation using a femtosecond near-infrared (NIR) laser has the advantages that it enables simultaneous excitation of multiple dyes and achieves very high signal-to-noise ratio through simplified filtering and fluorescence background reduction. By matching the excitation volume to the size of a cell, single-cell detection is ensured. Labeling of cells by targeted nanoparticles with multiple fluorophores enables normalization of the fluorescence signal and thus ratiometric measurements under nonuniform excitation. Quantitative size measurements can also be done even under conditions of nonuniform flow via a two-beam layout. This innovative detection scheme not only considerably simplifies the fluid flow system and the excitation and collection optics, it opens the way to quantitative cytometry in simple and compact microfluidics systems, or in vivo. Real-time detection of fluorescent microbeads in the vasculature of mouse ear demonstrates the ability to do flow cytometry in vivo. The conditions required to perform quantitative in vivo cytometry on labeled cells will be presented.

  3. PIE Nacelle Flow Analysis and TCA Inlet Flow Quality Assessment

    Science.gov (United States)

    Shieh, C. F.; Arslan, Alan; Sundaran, P.; Kim, Suk; Won, Mark J.

    1999-01-01

    This presentation includes three topics: (1) Analysis of isolated boattail drag; (2) Computation of Technology Concept Airplane (TCA)-installed nacelle effects on aerodynamic performance; and (3) Assessment of TCA inlet flow quality.

  4. Homotopy between plane Couette flow and Pipe flow

    Science.gov (United States)

    Nagata, Masato; Deguchi, Kengo

    2014-11-01

    In order to investigate symmetry connections between two canonical shear flows, i.e. plane Couette (PCF) and pipe flow (PF), which are linearly stable for all Reynolds numbers and therefore undergo subcritical transition, we take annular Poiseuille-Couette flow (APCF) as an intermediary Although PCF and PF are very different geometrically, APCF recovers PCF by taking the narrow gap limit, and also PF by taking the limit of vanishing inner cylinder where a homotopy of the basis functions from no-slip to regular conditions at the centre is considered. We show that the double-layered mirror-symmetric solutions in sliding Couette flow (APCF without axial pressure gradient) found by Deguchi & Nagata (2011) can be traced back to the mirror-symmetric solutions in PCF. Also we show that only the double-layered solution successfully reaches the PF limit, reproducing the mirror-symmetric solution in PF classified as M1 by Pringle & Kerswell (2007).

  5. Mathematical Modeling of Electrolyte Flow Dynamic Patterns and Volumetric Flow Penetrations in the Flow Channel over Porous Electrode Layered System in Vanadium Flow Battery with Serpentine Flow Field Design

    OpenAIRE

    Ke, Xinyou; Prahl, Joseph M.; Alexander, J. Iwan D.; Savinell, Robert F.

    2016-01-01

    In this work, a two-dimensional mathematical model is developed to study the flow patterns and volumetric flow penetrations in the flow channel over the porous electrode layered system in vanadium flow battery with serpentine flow field design. The flow distributions at the interface between the flow channel and porous electrode are examined. It is found that the non-linear pressure distributions can distinguish the interface flow distributions under the ideal plug flow and ideal parabolic fl...

  6. American Association for Clinical Chemistry

    Science.gov (United States)

    ... Education Credits Certification Resources Career Guidance Publications Clinical Chemistry Clinical Laboratory News The Journal of Applied Laboratory Medicine Clinical and Forensic Toxicology News Clinical Laboratory Marketplace Books and Multimedia ...

  7. Unsteady flow about a circulation control airfoil

    Institute of Scientific and Technical Information of China (English)

    刘晶昌; 孙茂; 吴礼义

    1996-01-01

    The unsteady flow around a circulation control (CC) airfoil was investigated with Navier-Stokes method,which includes the flow around CC airfoil with pulsating jet,the flow around oscillating CC airfoil,and the flow around oscillating CC airfoil with pulsating jet.Dynamic properties of the flow and the aerodynamic forces were rewaled.

  8. 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...... that runs in time O(n^3/log n) on a unit cost random-access memory model machine. Moreover, we refine the initial flow analysis into two more precise analyses incorporating notions of reachability. We give subcubic algorithms for these more precise analyses and relate them to an existing analysis from...

  9. Exploration EVA Purge Flow Assessment

    Science.gov (United States)

    Navarro, Moses; Conger, Bruce; Campbell, Colin

    2011-01-01

    An advanced future spacesuit will require properly sized suit and helmet purge flow rates in order to sustain a crew member with a failed Portable Life Support System (PLSS) during an Extravehicular Activity (EVA). A computational fluid dynamics evaluation was performed to estimate the helmet purge flow rate required to washout carbon dioxide and to prevent the condensing ("fogging") of water vapor on the helmet visor. An additional investigation predicted the suit purge flow rate required to provide sufficient convective cooling to keep the crew member comfortable. This paper summarizes the results of these evaluations.

  10. Recent Development in Flow Separation.

    Science.gov (United States)

    1980-05-01

    become so great that the boundary, layer thickness is comparable with the radius, the boun- dary layer approximation breaks down. In the corner...process. 4.5 Co-Current Flow Tests on a jet aligned with free stream in a wind tunnel show that due to de’lections, the tunnel walls have a great ...Fig.ViT.5. The critical stream line devides the flow downstream through the neck from the flow circulating in the base region. If no injection takes place

  11. Transient eddy current flow metering

    Science.gov (United States)

    Forbriger, J.; Stefani, F.

    2015-10-01

    Measuring local velocities or entire flow rates in liquid metals or semiconductor melts is a notorious problem in many industrial applications, including metal casting and silicon crystal growth. We present a new variant of an old technique which relies on the continuous tracking of a flow-advected transient eddy current that is induced by a pulsed external magnetic field. This calibration-free method is validated by applying it to the velocity of a spinning disk made of aluminum. First tests at a rig with a flow of liquid GaInSn are also presented.

  12. Transient eddy current flow metering

    CERN Document Server

    Forbriger, Jan

    2015-01-01

    Measuring local velocities or entire flow rates in liquid metals or semiconductor melts is a notorious problem in many industrial applications, including metal casting and silicon crystal growth. We present a new variant of an old technique which relies on the continuous tracking of a flow-advected transient eddy current that is induced by a pulsed external magnetic field. This calibration-free method is validated by applying it to the velocity of a spinning disk made of aluminum. First tests at a rig with a flow of liquid GaInSn are also presented.

  13. POSIVA groundwater flow measuring techniques

    Energy Technology Data Exchange (ETDEWEB)

    Oehberg, A. [Saanio and Riekkola Consulting Engineers, Helsinki (Finland); Rouhiainen, P. [PRG-Tec Oy (Finland)

    2000-08-01

    Posiva Oy has carried out site characterisation for the final disposal of spent nuclear fuel in Finland since 1987. To meet the demanding needs to measure the hydraulic parameters in bedrock Posiva launched development of new flowmeter techniques including measuring methods and equipment in co-operation with PRG-Tec Oy. The techniques have been tested and used in the ongoing site investigations in Finland, in the underground Hard Rock Laboratory (HRL) at Aespoe in Sweden and in URL in Canada. The new methods are called difference flow and transverse flow methods. The difference flow method includes two modes, normal and detailed flow logging methods. In the normal mode the flow rate measurement is based on thermal pulse and thermal dilution methods, in the detailed logging mode only on thermal dilution method. The measuring ranges for flow rate with thermal pulse and dilution methods are 0.1-10 ml/min and 2-5000 ml/min, respectively. The difference flow method(normal mode) for small flows (0.1-10 ml/min) is based on measuring the pulse transit time and direction of a thermal pulse in the sensor. For high flows (2-5000 ml/min) the method is based on thermal dilution rate of a sensor. Direction is measured with monitoring thermistors. Inflow or outflow in the test interval is created due to natural or by pumping induced differences between heads in the borehole water and groundwater around the borehole. The single point resistance (and the temperature of borehole water) measurement is carried out simultaneously with the difference flow measurements, both in normal and detailed flow logging modes, while the tool is moving. The result is utilised for checking the exact depth of the tool. As the result a continuous log is obtained from which single fractures can be detected. The transverse flowmeter is able to measure the groundwater flow across a borehole. A special packer system guides the flow through the flow sensors. Four inflatable seals between conventional

  14. Information Flow Analysis for VHDL

    DEFF Research Database (Denmark)

    Tolstrup, Terkel Kristian; Nielson, Flemming; Nielson, Hanne Riis

    2005-01-01

    We describe a fragment of the hardware description language VHDL that is suitable for implementing the Advanced Encryption Standard algorithm. We then define an Information Flow analysis as required by the international standard Common Criteria. The goal of the analysis is to identify the entire...... information flow through the VHDL program. The result of the analysis is presented as a non-transitive directed graph that connects those nodes (representing either variables or signals) where an information flow might occur. We compare our approach to that of Kemmerer and conclude that our approach yields...

  15. Thermographic Detection of separated Flow

    Science.gov (United States)

    Dollinger, C.; Balaresque, N.; Schaffarczyk, A. P.; Fischer, A.

    2016-09-01

    Thermographic wind tunnel measurements, both on a cylinder as well as on a 2D airfoil, were performed at various Reynolds numbers in order to evaluate the possibility of detecting and visualizing separated flow areas. A new approach by acquiring a series of thermographic images and applying a spatial-temporal statistical analysis allows improving both the resolution and the information content of the thermographic images. Separated flow regions become visible and laminar/turbulent transitions can be detected more accurately. The knowledge about possibly present stall cells can be used to confirm two-dimensional flow conditions and support the development of more effective and silent rotorblades.

  16. of Transient Flows in Turbomachines

    Directory of Open Access Journals (Sweden)

    Alexander Wiedermann

    1999-01-01

    Full Text Available This paper focuses on development and validation of a viscous solver for the computation of unsteady flows in turbomachinery blade rows and stages consisting of rotors and stators. The code has been evolved from steady-state single flow solvers developed by Wiedermann based on time-marching finite difference schemes. A two-equation eddy viscosity model is applied, and the wall boundary conditions are determined by the y+-distance of the first grid line away from the wall. For the solution of transient flow fields the original time-stepping algorithm is replaced by a time-accurate scheme.

  17. BPS dyons and Hesse flow

    Science.gov (United States)

    Van den Bleeken, Dieter

    2012-02-01

    We revisit BPS solutions to classical N = 2 low energy effective gauge theories. It is shown that the BPS equations can be solved in full generality by the introduction of a Hesse potential, a symplectic analog of the holomorphic prepotential. We explain how for non-spherically symmetric, non-mutually local solutions, the notion of attractor flow generalizes to gradient flow with respect to the Hesse potential. Furthermore we show that in general there is a non-trivial magnetic complement to this flow equation that is sourced by the momentum current in the solution.

  18. Cerebral blood flow tomography with xenon-133

    Energy Technology Data Exchange (ETDEWEB)

    Lassen, N.A.

    1985-10-01

    Cerebral blood flow (CBF) can be measured tomographically by inhalation of Xenon-/sup 133/. The calculation is based on taking a sequence of tomograms during the wash-in and wash-out phase of the tracer. Due to the dynamic nature of the process, a highly sensitive and fast moving single photon emission computed tomograph (SPECT) is required. Two brain-dedicated SPECT systems designed for this purpose are mentioned, and the method is described with special reference to the limitations inherent in the soft energy of the 133Xe primary photons. CBF tomography can be used for a multitude of clinical and investigative purposes. This article discusses in particular its use for the selection of patients with carotid occlusion for extracranial/intracranial bypass surgery, for detection of severe arterial spasm after aneurysm bleeding, and for detection of low flow areas during severe migraine attacks. The use of other tracers for CBF tomography using SPECT is summarized with emphasis on the /sup 99m/Tc chelates that freely pass the intact blood-brain barrier. The highly sensitive brain-dedicated SPECT systems described are a prerequisite for achieving high resolution tomograms with such tracers.

  19. High Flow Nasal Cannulae in preterm infants

    Directory of Open Access Journals (Sweden)

    F. Ciuffini

    2013-06-01

    Full Text Available Despite of improved survival of premature infants, the incidence of long term pulmonary complications, mostly associated with ventilation-induced lung injury, remains high. Non invasive ventilation (NIV is able to reduce the adverse effects of mechanical ventilation. Although nasal continuous positive airway pressure (NCPAP is an effective mode of NIV, traumatic nasal complications and intolerance of the nasal interface are common. Recently high flow nasal cannula (HFNC is emerging as an efficient, better tolerated form of NIV, allowing better access to the baby’s face, which may improve nursing, feeding and bonding. The aim of this review is to discuss the available evidence of effectiveness and safety of HFNC in preterm newborns with respiratory distress syndrome (RDS. It is known that distending pressure generated by HFNC increases with increasing flow rate and decreasing infant size and varies according to the amount of leaks by nose and mouth. The effects of HFNC on lung mechanics, its clinical efficacy and safety are still insufficiently investigated. In conclusion, there is a growing evidence of the feasibility of HFNC as an alternative mode of NIV. However, further larger randomized trials are required, before being able to recommend HFNC in the treatment of moderate respiratory distress of preterm infants.

  20. Optimal Power Flow Control by Rotary Power Flow Controller

    Directory of Open Access Journals (Sweden)

    KAZEMI, A.

    2011-05-01

    Full Text Available This paper presents a new power flow model for rotary power flow controller (RPFC. RPFC injects a series voltage into the transmission line and provides series compensation and phase shifting simultaneously. Therefore, it is able to control the transmission line impedance and the active power flow through it. An RPFC is composed mainly of two rotary phase shifting transformers (RPST and two conventional (series and shunt transformers. Structurally, an RPST consists of two windings (stator and rotor windings. The rotor windings of the two RPSTs are connected in parallel and their stator windings are in series. The injected voltage is proportional to the vector sum of the stator voltages and so its amplitude and angle are affected by the rotor position of the two RPSTs. This paper, describes the steady state operation and single-phase equivalent circuit of the RPFC. Also in this paper, a new power flow model, based on power injection model of flexible ac transmission system (FACTS controllers, suitable for the power flow analysis is introduced. Proposed model is used to solve optimal power flow (OPF problem in IEEE standard test systems incorporating RPFC and the optimal settings and location of the RPFC is determined.