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Sample records for blood circulation model

  1. A blood circulation model for reference man

    Energy Technology Data Exchange (ETDEWEB)

    Leggett, R.W.; Eckerman, K.F. [Oak Ridge National Lab., TN (United States). Health Sciences Research Div.; Williams, L.R. [Indiana Univ., South Bend, IN (United States). Div. of Liberal Arts and Sciences

    1999-01-01

    This paper describes a dynamic blood circulation model that predicts the movement and gradual dispersal of a bolus of material in the circulation after its intravascular injection into an adult human. The main purpose of the model is to improve the dosimetry of internally deposited radionuclides that decay in the circulation to a significant extent. The total blood volume is partitioned into the blood contents of 24 separate organs or tissues, right heart chambers, left heart chambers, pulmonary circulation, arterial outflow to the systemic tissues (aorta and large arteries), and venous return from the systemic tissues (large veins). As a compromise between physical reality and computational simplicity, the circulation of blood is viewed as a system of first-order transfers between blood pools, with the delay time depending on the mean transit time across the pool. The model allows consideration of incomplete, tissue-dependent extraction of material during passage through the circulation and return of material from tissues to plasma.

  2. Exploring the Impact of Students' Learning Approach on Collaborative Group Modeling of Blood Circulation

    Science.gov (United States)

    Lee, Shinyoung; Kang, Eunhee; Kim, Heui-Baik

    2015-01-01

    This study aimed to explore the effect on group dynamics of statements associated with deep learning approaches (DLA) and their contribution to cognitive collaboration and model development during group modeling of blood circulation. A group was selected for an in-depth analysis of collaborative group modeling. This group constructed a model in a…

  3. One dimensional and multiscale models for blood flow circulation

    OpenAIRE

    Lamponi, Daniele

    2004-01-01

    The aim of this work is to provide mathematically sound and computationally effective tools for the numerical simulation of the interaction between fluid and structures as occurring, for instance, in the simulation of the human cardiovascular system. This problem is global, in the sense that local changes can modify the solution far away. From the point of view of computing and modelling this calls for the use of multiscale methods, where simplified models are used to treat the global problem...

  4. A computational model of the fetal circulation to quantify blood redistribution in intrauterine growth restriction.

    Directory of Open Access Journals (Sweden)

    Patricia Garcia-Canadilla

    2014-06-01

    Full Text Available Intrauterine growth restriction (IUGR due to placental insufficiency is associated with blood flow redistribution in order to maintain delivery of oxygenated blood to the brain. Given that, in the fetus the aortic isthmus (AoI is a key arterial connection between the cerebral and placental circulations, quantifying AoI blood flow has been proposed to assess this brain sparing effect in clinical practice. While numerous clinical studies have studied this parameter, fundamental understanding of its determinant factors and its quantitative relation with other aspects of haemodynamic remodeling has been limited. Computational models of the cardiovascular circulation have been proposed for exactly this purpose since they allow both for studying the contributions from isolated parameters as well as estimating properties that cannot be directly assessed from clinical measurements. Therefore, a computational model of the fetal circulation was developed, including the key elements related to fetal blood redistribution and using measured cardiac outflow profiles to allow personalization. The model was first calibrated using patient-specific Doppler data from a healthy fetus. Next, in order to understand the contributions of the main parameters determining blood redistribution, AoI and middle cerebral artery (MCA flow changes were studied by variation of cerebral and peripheral-placental resistances. Finally, to study how this affects an individual fetus, the model was fitted to three IUGR cases with different degrees of severity. In conclusion, the proposed computational model provides a good approximation to assess blood flow changes in the fetal circulation. The results support that while MCA flow is mainly determined by a fall in brain resistance, the AoI is influenced by a balance between increased peripheral-placental and decreased cerebral resistances. Personalizing the model allows for quantifying the balance between cerebral and peripheral

  5. A computational model of the fetal circulation to quantify blood redistribution in intrauterine growth restriction.

    Science.gov (United States)

    Garcia-Canadilla, Patricia; Rudenick, Paula A; Crispi, Fatima; Cruz-Lemini, Monica; Palau, Georgina; Camara, Oscar; Gratacos, Eduard; Bijnens, Bart H; Bijens, Bart H

    2014-06-01

    Intrauterine growth restriction (IUGR) due to placental insufficiency is associated with blood flow redistribution in order to maintain delivery of oxygenated blood to the brain. Given that, in the fetus the aortic isthmus (AoI) is a key arterial connection between the cerebral and placental circulations, quantifying AoI blood flow has been proposed to assess this brain sparing effect in clinical practice. While numerous clinical studies have studied this parameter, fundamental understanding of its determinant factors and its quantitative relation with other aspects of haemodynamic remodeling has been limited. Computational models of the cardiovascular circulation have been proposed for exactly this purpose since they allow both for studying the contributions from isolated parameters as well as estimating properties that cannot be directly assessed from clinical measurements. Therefore, a computational model of the fetal circulation was developed, including the key elements related to fetal blood redistribution and using measured cardiac outflow profiles to allow personalization. The model was first calibrated using patient-specific Doppler data from a healthy fetus. Next, in order to understand the contributions of the main parameters determining blood redistribution, AoI and middle cerebral artery (MCA) flow changes were studied by variation of cerebral and peripheral-placental resistances. Finally, to study how this affects an individual fetus, the model was fitted to three IUGR cases with different degrees of severity. In conclusion, the proposed computational model provides a good approximation to assess blood flow changes in the fetal circulation. The results support that while MCA flow is mainly determined by a fall in brain resistance, the AoI is influenced by a balance between increased peripheral-placental and decreased cerebral resistances. Personalizing the model allows for quantifying the balance between cerebral and peripheral-placental remodeling

  6. Exploring Secondary Students' Epistemological Features Depending on the Evaluation Levels of the Group Model on Blood Circulation

    Science.gov (United States)

    Lee, Shinyoung; Kim, Heui-Baik

    2014-01-01

    The purpose of this study is to identify the epistemological features and model qualities depending on model evaluation levels and to explore the reasoning process behind high-level evaluation through small group interaction about blood circulation. Nine groups of three to four students in the eighth grade participated in the modeling practice.…

  7. A model of the circulating blood for use in radiation dose calculations

    Energy Technology Data Exchange (ETDEWEB)

    Hui, T.E.; Poston, J.W. Sr.

    1987-01-01

    Over the last few years there has been a significant increase in the use of radionuclides in leukocyte, platelet, and erythrocyte imaging procedures. Radiopharmaceutical used in these procedures are confined primarily to the blood, have short half-lives, and irradiate the body as they move through the circulatory system. There is a need for a model, to describe the circulatory system in an adult human, which can be used to provide radiation absorbed dose estimates for these procedures. A simplified model has been designed assuming a static circulatory system and including major organs of the body. The model has been incorporated into the MIRD phantom and calculations have been completed for a number of exposure situations and radionuclides of clinical importance. The model will be discussed in detail and results of calculations using this model will be presented.

  8. A model of the circulating blood for use in radiation dose calculations

    Energy Technology Data Exchange (ETDEWEB)

    Hui, T.E.; Poston, J.W. Sr.

    1987-12-31

    Over the last few years there has been a significant increase in the use of radionuclides in leukocyte, platelet, and erythrocyte imaging procedures. Radiopharmaceutical used in these procedures are confined primarily to the blood, have short half-lives, and irradiate the body as they move through the circulatory system. There is a need for a model, to describe the circulatory system in an adult human, which can be used to provide radiation absorbed dose estimates for these procedures. A simplified model has been designed assuming a static circulatory system and including major organs of the body. The model has been incorporated into the MIRD phantom and calculations have been completed for a number of exposure situations and radionuclides of clinical importance. The model will be discussed in detail and results of calculations using this model will be presented.

  9. Elderly bioheat modeling: changes in physiology, thermoregulation, and blood flow circulation.

    Science.gov (United States)

    Rida, Mohamad; Ghaddar, Nesreen; Ghali, Kamel; Hoballah, Jamal

    2014-11-01

    A bioheat model for the elderly was developed focusing on blood flow circulatory changes that influence their thermal response in warm and cold environments to predict skin and core temperatures for different segments of the body especially the fingers. The young adult model of Karaki et al. (Int J Therm Sci 67:41-51, 2013) was modified by incorporation of the physiological thermoregulatory and vasomotor changes based on literature observations of physiological changes in the elderly compared to young adults such as lower metabolism and vasoconstriction diminished ability, skin blood flow and its minimum and maximum values, the sweating values, skin fat thickness, as well as the change in threshold parameter related to core or skin temperatures which triggers thermoregulatory action for sweating, maximum dilatation, and maximum constriction. The developed model was validated with published experimental data for elderly exposure to transient and steady hot and cold environments. Predicted finger skin temperature, mean skin temperature, and core temperature were in agreement with published experimental data at a maximum error less than 0.5 °C in the mean skin temperature. The elderly bioheat model showed an increase in finger skin temperature and a decrease in core temperature in cold exposure while it showed a decrease in finger skin temperature and an increase in core temperature in hot exposure.

  10. Evaluation of coronary blood flow velocity during cardiac arrest with circulation maintained through mechanical chest compressions in a porcine model

    Directory of Open Access Journals (Sweden)

    Wagner Henrik

    2011-12-01

    Full Text Available Abstract Background Mechanical chest compressions (CCs have been shown capable of maintaining circulation in humans suffering cardiac arrest for extensive periods of time. Reports have documented a visually normalized coronary blood flow during angiography in such cases (TIMI III flow, but it has never been actually measured. Only indirect measurements of the coronary circulation during cardiac arrest with on-going mechanical CCs have been performed previously through measurement of the coronary perfusion pressure (CPP. In this study our aim was to correlate average peak coronary flow velocity (APV to CPP during mechanical CCs. Methods In a closed chest porcine model, cardiac arrest was established through electrically induced ventricular fibrillation (VF in eleven pigs. After one minute, mechanical chest compressions were initiated and then maintained for 10 minutes upon which the pigs were defibrillated. Measurements of coronary blood flow in the left anterior descending artery were made at baseline and during VF with a catheter based Doppler flow fire measuring APV. Furthermore measurements of central (thoracic venous and arterial pressures were also made in order to calculate the theoretical CPP. Results Average peak coronary flow velocity was significantly higher compared to baseline during mechanical chests compressions and this was observed during the entire period of mechanical chest compressions (12 - 39% above baseline. The APV slowly declined during the 10 min period of mechanical chest compressions, but was still higher than baseline at the end of mechanical chest compressions. CPP was simultaneously maintained at > 20 mmHg during the 10 minute episode of cardiac arrest. Conclusion Our study showed good correlation between CPP and APV which was highly significant, during cardiac arrest with on-going mechanical CCs in a closed chest porcine model. In addition APV was even higher during mechanical CCs compared to baseline. Mechanical

  11. Blood vessels, circulation and blood pressure.

    Science.gov (United States)

    Hendry, Charles; Farley, Alistair; McLafferty, Ella

    This article, which forms part of the life sciences series, describes the vessels of the body's blood and lymphatic circulatory systems. Blood pressure and its regulatory systems are examined. The causes and management of hypertension are also explored. It is important that nurses and other healthcare professionals understand the various mechanisms involved in the regulation of blood pressure to prevent high blood pressure or ameliorate its damaging consequences.

  12. [William Harvey, discoverer of the blood circulation].

    Science.gov (United States)

    v Mühlendahl, K E

    2007-06-01

    William Harvey (1578-1657), living at the turn to modern times, scientifically speaking, was an eminent physician and scientist. He developed the concept of the circulation of the blood and his findings have proved to be correct in nearly all details to this day. He published his physiological findings and interpretations in a small, albeit epoch-making, volume: Exercitatio anatomica de motu cordis et sanguinis in animalibus, published in Frankfurt in 1628. On the occasion of the 350th anniversary of his death on June 3, 2007, this essay commemorates the work of this important physician, illustrating his brilliant conception of the blood circulation by quoting passages from De motu cordis et sanguinis.

  13. Modelled Circulation In Storfjorden

    Science.gov (United States)

    Skogseth, R.; Asplin, L.

    The model area Storfjorden is situated between the islands Spitsbergen, Barentsöya and Edgeöya at the Svalbard Archipelago. The entrance of Storfjorden is defined by a shallow bank Storfjordbanken and some small islands Tusenöyane in southeast, and by an 115m deep sill at about 76 45' N in the south. Maximum depth in Storfjorden is 190m, which is surrounded by gradually shallower shelves in the north, the east and southeast. A steep bottom slope is present on the western side of Storfjorden. He- leysundet and Freemansundet, two sounds between respectively Spitsbergen and Bar- entsöya, and Barentsöya and Edgeöya, define two narrow and shallow entrances in the north and northeast connecting Storfjorden with the northwestern Barents Sea. Strong tidal currents exist in Heleysundet (4-5ms-1) and Freemansundet (2-3ms-1), but the general circulation in Storfjorden is not well known. The coastal current in Storfjor- den is cyclonic directed into Storfjorden south of Edgeöya from the East Spitsbergen Current and out of Storfjorden south of Spitsbergen where it is called Sørkappstrøm- men. A three-dimensional sigma layered numerical ocean model called Bergen Ocean Model (BOM) was used to simulate the circulation in Storfjorden with Freemansundet opened. Two simulations were carried out, one with heat flux (100 Wm-2) and one without heat flux from the ocean to the atmosphere. The heat flux was applied only in the proper fjord area north of the sill and not outside as a crude approximation of the effects of a polynya in the sea ice cover during winter. Both simulations had a 4km horizontal resolution and 21 sigma layers. The model is forced by winds (from the NCEP reanalyzed fields) and tides. Initial fields are from the DNMI/IMR climatol- ogy. The model simulation without heat flux gave a circulation heavily dependent on tidal forcing, showing strong tidal currents up to 2ms-1 in Freemansundet, between Tusenöyane and on Storfjordbanken southwest of Edgeöya. Earlier

  14. Metabolism of nanomaterials in vivo: blood circulation and organ clearance.

    Science.gov (United States)

    Wang, Bing; He, Xiao; Zhang, Zhiyong; Zhao, Yuliang; Feng, Weiyue

    2013-03-19

    occurring between NMs and between NMs and the biological milieu after the introduction of NMs into living systems may further influence the blood circulation and clearance profiles of NMs. These interactions can alter properties such as agglomeration, phase transformations, dissolution, degradation, protein adsorption, and surface reactivity. The physicochemical properties of NMs change dynamically in vivo thereby making the metabolism of NMs complex and difficult to predict. The development of in situ, real-time, and quantitative techniques, in vitro assays, and the adaptation of physiologically-based pharmacokinetic (PBPK) and quantitative structure-activity relationship (QNSAR) modeling for NMs will streamline future in vivo studies.

  15. EXTRACORPOREAL CIRCULATION: EFFECT OF LONG-TERM (24-HOUR) CIRCULATION ON BLOOD COMPONENTS

    OpenAIRE

    Solberg, Robert Glen

    2010-01-01

    Extracorporeal circulation damages blood and causes harmful side effects such as stroke and/or systemic inflammatory response in patients. Reactions of blood components to extracorporeal circulation include complement and inflammatory reactions, coagulation and thrombogenesis, frank hemolysis, and platelet activation and adhesion to the extracorporeal circuit. Non-physiologic pressure and flow produced by blood pumps contribute to blood injury. Two pump types, roller and centrifugal, are u...

  16. Factors circulating in the blood of type 2 diabetes mellitus patients affect osteoblast maturation - description of a novel in vitro model.

    Science.gov (United States)

    Ehnert, Sabrina; Freude, Thomas; Ihle, Christoph; Mayer, Larissa; Braun, Bianca; Graeser, Jessica; Flesch, Ingo; Stöckle, Ulrich; Nussler, Andreas K; Pscherer, Stefan

    2015-03-15

    Type 2 diabetes mellitus (T2DM) is one of the most frequent metabolic disorders in industrialized countries. Among other complications, T2DM patients have an increased fracture risk and delayed fracture healing. We have demonstrated that supraphysiological glucose and insulin levels inhibit primary human osteoblasts׳ maturation. We aimed at developing a more physiologically relevant in vitro model to analyze T2DM-mediated osteoblast changes. Therefore, SCP-1-immortalized pre-osteoblasts were differentiated with T2DM or control (non-obese and obese) sera. Between both control groups, no significant changes were observed. Proliferation was significantly increased (1.69-fold), while AP activity and matrix mineralization was significantly reduced in the T2DM group. Expression levels of osteogenic marker genes and transcription factors were altered, e.g. down-regulation of RUNX2 and SP-7 or up-regulation of STAT1, in the T2DM group. Active TGF-β levels were significantly increased (1.46-fold) in T2DM patients׳ sera. SCP-1 cells treated with these sera showed significantly increased TGF-β signaling (2.47-fold). Signaling inhibition effectively restored osteoblast maturation in the T2DM group. Summarizing our data, SCP-1 cells differentiated in the presence of T2DM patients׳ serum exhibit reduced osteoblast function. Thus, this model has a high physiological impact, as it can identify circulating factors in T2DM patients׳ blood that may affect bone function, e.g. TGF-β.

  17. Influence of obesity and androgen deficiency on prostatic blood circulation

    Directory of Open Access Journals (Sweden)

    I. A. Tyuzikov

    2012-01-01

    Full Text Available In Study at 120 Diabetes Mellitus II type men the high frequency Obesity (71,7% and Androgen Deficiency (52,8—64,5% of the patients depending on a degree of the indemnification and them pathogenic authentic communications were shown. The blood level of total testosterone was represented by the critical factor of Prostatic arterial Blood Circulation. Obesity and Androgen Deficiency are seem as independent risk factors to development of ischemic prostatopathy, such as Prostatic blood circulation Disorders can develop earlier than other variants of the diabetic microangiophaty.

  18. Factors circulating in the blood of type 2 diabetes mellitus patients affect osteoblast maturation – Description of a novel in vitro model

    Energy Technology Data Exchange (ETDEWEB)

    Ehnert, Sabrina, E-mail: sabrina.ehnert@gmail.com [BG Trauma Center, Eberhard Karls Universität Tübingen, Schnarrenbergstr. 95, D-72076 Tübingen (Germany); Freude, Thomas, E-mail: tfreude@bgu-tuebingen.de [BG Trauma Center, Eberhard Karls Universität Tübingen, Schnarrenbergstr. 95, D-72076 Tübingen (Germany); Ihle, Christoph, E-mail: cihle@bgu-tuebingen.de [BG Trauma Center, Eberhard Karls Universität Tübingen, Schnarrenbergstr. 95, D-72076 Tübingen (Germany); Mayer, Larissa, E-mail: lara.nk@gmail.com [BG Trauma Center, Eberhard Karls Universität Tübingen, Schnarrenbergstr. 95, D-72076 Tübingen (Germany); Braun, Bianca, E-mail: bianca.braun@med.uni-tuebingen.de [BG Trauma Center, Eberhard Karls Universität Tübingen, Schnarrenbergstr. 95, D-72076 Tübingen (Germany); Graeser, Jessica, E-mail: jessica.graeser@student.reutlingen-university.de [BG Trauma Center, Eberhard Karls Universität Tübingen, Schnarrenbergstr. 95, D-72076 Tübingen (Germany); Flesch, Ingo, E-mail: iflesch@bgu-tuebingen.de [BG Trauma Center, Eberhard Karls Universität Tübingen, Schnarrenbergstr. 95, D-72076 Tübingen (Germany); and others

    2015-03-15

    Type 2 diabetes mellitus (T2DM) is one of the most frequent metabolic disorders in industrialized countries. Among other complications, T2DM patients have an increased fracture risk and delayed fracture healing. We have demonstrated that supraphysiological glucose and insulin levels inhibit primary human osteoblasts' maturation. We aimed at developing a more physiologically relevant in vitro model to analyze T2DM-mediated osteoblast changes. Therefore, SCP-1-immortalized pre-osteoblasts were differentiated with T2DM or control (non-obese and obese) sera. Between both control groups, no significant changes were observed. Proliferation was significantly increased (1.69-fold), while AP activity and matrix mineralization was significantly reduced in the T2DM group. Expression levels of osteogenic marker genes and transcription factors were altered, e.g. down-regulation of RUNX2 and SP-7 or up-regulation of STAT1, in the T2DM group. Active TGF-β levels were significantly increased (1.46-fold) in T2DM patients' sera. SCP-1 cells treated with these sera showed significantly increased TGF-β signaling (2.47-fold). Signaling inhibition effectively restored osteoblast maturation in the T2DM group. Summarizing our data, SCP-1 cells differentiated in the presence of T2DM patients' serum exhibit reduced osteoblast function. Thus, this model has a high physiological impact, as it can identify circulating factors in T2DM patients' blood that may affect bone function, e.g. TGF-β. - Highlights: • We present here a physiologically relevant in vitro model for diabetic osteopathy. • Blood of T2DM patients contains factors that affect osteoblasts' function. • The model developed here can be used to identify these factors, e.g. TGF-β. • Blocking TGF-β signaling partly rescues the osteoblasts' function in the T2DM group. • The model is useful to demonstrate the role of single factors in diabetic osteopathy.

  19. Ultrasonic Doppler blood flow meter for extracorporeal circulation

    Science.gov (United States)

    Dantas, Ricardo G.; Costa, Eduardo T.; Maia, Joaquim M.; Nantes Button, Vera L. d. S.

    2000-04-01

    In cardiac surgeries it is frequently necessary to carry out interventions in internal heart structures, and where the blood circulation and oxygenation are made by artificial ways, out of the patient's body, in a procedure known as extracorporeal circulation (EC). During this procedure, one of the most important parameters, and that demands constant monitoring, is the blood flow. In this work, an ultrasonic pulsed Doppler blood flowmeter, to be used in an extracorporeal circulation system, was developed. It was used a 2 MHz ultrasonic transducer, measuring flows from 0 to 5 liters/min, coupled externally to the EC arterial line destined to adults perfusion (diameter of 9.53 mm). The experimental results using the developed flowmeter indicated a maximum deviation of 3.5% of full scale, while the blood flow estimator based in the rotation speed of the peristaltic pump presented deviations greater than 20% of full scale. This ultrasonic flowmeter supplies the results in a continuous and trustworthy way, and it does not present the limitations found in those flowmeters based in other transduction methods. Moreover, due to the fact of not being in contact with the blood, it is not disposable and it does not need sterilization, reducing operational costs and facilitating its use.

  20. 3D microfilter device for viable circulating tumor cell (CTC) enrichment from blood.

    Science.gov (United States)

    Zheng, Siyang; Lin, Henry K; Lu, Bo; Williams, Anthony; Datar, Ram; Cote, Richard J; Tai, Yu-Chong

    2011-02-01

    Detection of circulating tumor cells has emerged as a promising minimally invasive diagnostic and prognostic tool for patients with metastatic cancers. We report a novel three dimensional microfilter device that can enrich viable circulating tumor cells from blood. This device consists of two layers of parylene membrane with pores and gap precisely defined with photolithography. The positions of the pores are shifted between the top and bottom membranes. The bottom membrane supports captured cells and minimize the stress concentration on cell membrane and sustain cell viability during filtration. Viable cell capture on device was investigated with scanning electron microscopy, confocal microscopy, and immunofluorescent staining using model systems of cultured tumor cells spiked in blood or saline. The paper presents and validates this new 3D microfiltration concept for circulation tumor cell enrichment application. The device provides a highly valuable tool for assessing and characterizing viable enriched circulating tumor cells in both research and clinical settings.

  1. Metabolic pathways that correlate with post-transfusion circulation of stored murine red blood cells.

    Science.gov (United States)

    de Wolski, Karen; Fu, Xiaoyoun; Dumont, Larry J; Roback, John D; Waterman, Hayley; Odem-Davis, Katherine; Howie, Heather L; Zimring, James C

    2016-05-01

    Transfusion of red blood cells is a very common inpatient procedure, with more than 1 in 70 people in the USA receiving a red blood cell transfusion annually. However, stored red blood cells are a non-uniform product, based upon donor-to-donor variation in red blood cell storage biology. While thousands of biological parameters change in red blood cells over storage, it has remained unclear which changes correlate with function of the red blood cells, as opposed to being co-incidental changes. In the current report, a murine model of red blood cell storage/transfusion is applied across 13 genetically distinct mouse strains and combined with high resolution metabolomics to identify metabolic changes that correlated with red blood cell circulation post storage. Oxidation in general, and peroxidation of lipids in particular, emerged as changes that correlated with extreme statistical significance, including generation of dicarboxylic acids and monohydroxy fatty acids. In addition, differences in anti-oxidant pathways known to regulate oxidative stress on lipid membranes were identified. Finally, metabolites were identified that differed at the time the blood was harvested, and predict how the red blood cells perform after storage, allowing the potential to screen donors at time of collection. Together, these findings map out a new landscape in understanding metabolic changes during red blood cell storage as they relate to red blood cell circulation.

  2. [Regulation of innate immunity during xenogenic changes in blood circulation].

    Science.gov (United States)

    Shevchenko, V S

    2001-01-01

    Calcium-dependent innate immune response with participation of the superfamily of immunoglobulins to several intra- and extracorporal xenobiotics were studied at 216 recipients during synthetic cardiac valves implantation or veins transplantation in coronary arteries. It was shown that immediate immune response to xenobiotics was manifested by generation of the antitissue anodical autoprecipitin with specificity to the surface cell membrane component. This reaction initiated and regulated the subsequent dynamics of the two different fibrinogen autoimmune complexes formation, resulting in development of the immunogenic damages of blood circulation. Correction of these rapid innate immune responses is important for prevention and normalisation of the xenogenic damages of blood circulation during trans- and implantation on the heart impaired with endocarditis or aterosclerosis.

  3. Harvey, by Hercules! The hero of the blood's circulation.

    Science.gov (United States)

    O'Rourke Boyle, Marjorie

    2013-01-01

    This article continues the analyses in Medical History 52 (2008), 73-90, 365-86 of William Harvey's self-understanding as the philosopher and discoverer of the blood's circulation. Harvey brilliantly and subversively assumed the persona of the mythological Hercules to embody his own anatomical labour in De motu cordis et sanguinis (1628). He reprised the role in self-defence against accusations in the College of Physicians, London, of his breach of faith with medical tradition. Harvey sought to usurp the medical epithet 'a second Hercules' by reforming humanist dependence on ancient texts as authoritative medicine. A knowledge of the theory and practice of Renaissance humanism discloses his identification with the Herculean labour of cleansing the Augean stable. He employed anatomical demonstration against Galen's porous cardiac septum, which admitted blood across the ventricles. Harvey's oath mehercule swore against Galen's Dia to assert the necessity of opening an alternate route for the blood flow. His Herculean labour was to dam the cardiac septum and divert the blood flow into a continuous channel through the arteries and veins. His circulation of the blood also imitated Hercules' successful dependence on the force of the water flow to flush the Augean stable. Harvey's copia did not denote a quantitative amount but a powerful supply. Harvey aspired to be, like Hercules, immortal, a term which the College belatedly acknowledged. This cultural analysis exposes Harvey's professional issues and personal ambitions, so to promote a fuller understanding of his historic role in medical discovery.

  4. Biomechanopharmacology in Evaluation of Herbs of Activating Blood Circulation to Remove Blood Stasis

    Institute of Scientific and Technical Information of China (English)

    LIAO Fu-long; CAO Jun

    2005-01-01

    Herbs of activating blood circulation to remove blood stasis(ABCRBS) are a category of over 10% in the modern Chinese Pharmacopoeia. A new borderline discipline, biomechanopharmacology, is shaping by the efforts of applying biomechanics in pharmacological studies of ABCRBS herbs. Biomechanics is involved in modeling of blood stasis syndrome (BSS) with mechanical force induced injury and model evaluation by shear stress monitoring for blood coagulation. Investigations showed that tetramethylpyrazine (TMP) contained in Ligusticum chuanxiong Hort and diallyl trisulfide (DT) extracted from garlic demonstrated inhibiting characteristics on vWF mediated platelet activation and thrombus formation occurring under high shear rates. The effect of TMP on shear-induced platelet aggregation might be due to inhibition of calcium channel activity since it showed significant inhibition on intracellular level of calcium demonstrated by laser confocal microscope. The combined effects of TMP and shear stress on rat cerebral microvascular endothelial cell (rCMEC) were investigated by various doses of TMP incorporated with different levels of shear stress generated by a rotational coneplate rheometer. The results indicated that apoptosis of rCMECs could be restrained by a combination of medial level of shear stress with a suitable dose of TMP. To study the influences of shear stress, pressure and TMP on angiogenesis of vascular endothelial cell, cultured rCMEC was pretreated in a flow chamber with independent adjustment for levels of shear stress and pressure, and then 3D cultured on Matrigel. The results indicate that combined effects of shear stress, pressure and TMP may influence angiogenesis significantly. We believe that research on interactions among blood shear stress, secretion of endothelial cell, and pharmacodynamics will be an interesting area of biomechanopharmacology. Herbs of ABCRBS and their extracts for protecting endothelial cells to maintain their normal functions are

  5. Detection of micrometastasis of gastric carcinoma in peripheral blood circulation

    Institute of Scientific and Technical Information of China (English)

    Xi-Mei Chen; Guo-Yu Chen; Zhi-Rong Wang; Feng-Shang Zhu; Xiao-Lei Wang; Xia Zhang

    2004-01-01

    AIM: To detect the micrometastasis of gastric carcinoma in peripheral blood circulation using immunomagnetic beads sorting technique and RT-PCR technique, and to discuss its significance and the difference between the two methods. METHODS: Density gradient centrifugation was used to isolate mononuclear cells from peripheral blood, immunomagnetic beads sorting technique and RT-PCR technique were used to detect the disseminated carcinoma cells. HE, immunocytochemical and immunofluorescence staining were also used to identify the characteristics of the cells separated with immunomagnetic beads sorting technique. RESULTS: Cells expressing cytokeratin were separated and enriched from the peripheral blood specimens of patients suffering from gastric carcinoma or chronic gastritis. After HE staining, two kinds of cells with little cytoplasm were found. Majority of these cells had small and round nuclei, even chromatins and the thickness of nuclear membrane was normal. Immunohistochemical staining indicated that there were CD34 and CD45 expression on the cell membrane of this kind of cells and these cells also showed expressed human telomerase reverse transcriptase by immunofluorescence staining, but the expression of carcinoembryonic antigen was absent. So, these cells might hematopoiesis precursors.Another kind of cells had larger and abnormal nuclei with thicker nuclear membranes. Massed chromatins and poly nucleoli were found in the nuclei. These cells expressed human telomerase reverse transcriptase and carcinoembryonic antigen, but CD34 and CD45 were not found on the cell membrane. So, these cells were considered as gastric carcinoma cells escaping from the original focuses and existing in the peripheral blood circulation. Carcinoma cells were found in 25 of 60(41.7%) specimens of peripheral blood from patients with gastric carcinoma, while there were no such cells separated from the blood specimens of chronic gastritis patients. The difference of positive rates of

  6. Does Every Cell Get Blood? Young Students' Discussions about Illustrations of Human Blood Circulation

    Science.gov (United States)

    Westman, Anna-Karin; Karlsson, Karl-Goran

    2016-01-01

    This article presents a study of how groups of young students discuss illustrations of human blood circulation. Transparency is not an innate quality of illustrations, visual information is always coded and interpretations are always related to culture and context. Results of this study are discussed with reference to Kress and van Leeuwens'…

  7. Effect of a deproteinized blood extract on the recovery of blood circulation in an ischaemic skin lesion.

    OpenAIRE

    Smahel, J.

    1982-01-01

    An experimental model was used to study the revascularization of an ischaemic skin lesion and the effect on this process of the blood extract Solcoseryl. Under the conditions given in the experiment, restoration of the circulation was by 2 modes--re-flow in the original vessels, and neovascularization. Solcoseryl given daily i.p. encouraged the re-flow phenomenon and therefore, by improving the microcirculation and nutrition, the healing of the ischaemic lesions.

  8. [Effect of exercise in water on maternal blood circulation].

    Science.gov (United States)

    Asai, M; Saegusa, S; Yamada, A; Suzuki, M; Noguchi, M; Niwa, S; Nakanishi, M

    1994-02-01

    To elucidate the effects of exercise in water on the maternal circulation, twenty normal pregnancies were examined under the following three conditions; 1) on the land at rest, 2) during water immersion and 3) after the exercise in water. Their gestational ages were from 25 to 37 weeks (31 +/- 4 weeks, mean +/- S.D., n = 20). We examined the blood pressure, the urine volume throughout the examination, CBC and the levels of vasopressin, plasma renin activity and human atrial natriuretic peptide (hANP). The blood volume calculated from the Hb and Ht were significantly (p water immersion (105.8 +/- 2.5%), even after the exercise (101.6 +/- 2.9%). Vasopressin was decreased during the water immersion and increased after the exercise, but plasma renin activity was decreased in these two conditions. The hANP concentration was significantly (p exercise in water and correlated with the urine volume (ml/hour) during the examination. These results show that the decline in blood pressure and the increase in the urine volume during the maternal swimming were caused by the decreased plasma renin activity and the increased hANP concentration resulted from the blood volume expansion during the exercise in water.

  9. Nanostructured Substrates for Capturing Circulating Tumor Cells in Whole Blood

    Science.gov (United States)

    Tseng, Hsian-Rong

    2009-03-01

    Over the past decade, circulating tumor cells (CTCs) has become an emerging ``biomarker'' for detecting early-stage cancer metastasis, predicting patient prognosis, as well as monitoring disease progression and therapeutic outcomes. However, isolation of CTCs has been technically challenging due to the extremely low abundance (a few to hundreds per ml) of CTCs among a high number of hematologic cells (109 per mL) in the blood. Our joint research team at UCLA has developed a new cell capture technology for quantification of CTCs in whole blood samples. Similar to most of the existing approaches, epithelial cell adhesion molecule antibody (anti-EpCAM) was grafted onto the surfaces to distinguish CTCs from the surrounding hematologic cells. The uniqueness of our technology is the use of nanostructured surfaces, which facilitates local topographical interactions between CTCs and substrates at the very first cell/substrate contacting time point. We demonstrated the ability of these nanostructured substrates to capture CTCs in whole blood samples with significantly improved efficiency and selectivity. The successful demonstration of this cell capture technology using brain, breast and prostate cancer cell lines encouraged us to test this approach in clinical setting. We have been able to bond our first validation study with a commercialized technology based on the use of immunomagnetic nanoparticles. A group of clinically well-characterized prostate cancer patients at UCLA hospital have been recruited and tested in parallel by these two technologies.

  10. Physiological levels of blood coagulation factors IX and X control coagulation kinetics in an in vitro model of circulating tissue factor

    Science.gov (United States)

    Tormoen, Garth W.; Khader, Ayesha; Gruber, András; McCarty, Owen J. T.

    2013-06-01

    Thrombosis significantly contributes to cancer morbidity and mortality. The mechanism behind thrombosis in cancer may be circulating tissue factor (TF), as levels of circulating TF are associated with thrombosis. However, circulating TF antigen level alone has failed to predict thrombosis in patients with cancer. We hypothesize that coagulation factor levels regulate the kinetics of circulating TF-induced thrombosis. Coagulation kinetics were measured as a function of individual coagulation factor levels and TF particle concentration. Clotting times increased when pooled plasma was mixed at or above a ratio of 4:6 with PBS. Clotting times increased when pooled plasma was mixed at or above a ratio of 8:2 with factor VII-depleted plasma, 7:3 with factor IX- or factor X-depleted plasmas, or 2:8 with factor II-, V- or VIII-depleted plasmas. Addition of coagulation factors VII, X, IX, V and II to depleted plasmas shortened clotting and enzyme initiation times, and increased enzyme generation rates in a concentration-dependent manner. Only additions of factors IX and X from low-normal to high-normal levels shortened clotting times and increased enzyme generation rates. Our results demonstrate that coagulation kinetics for TF particles are controlled by factor IX and X levels within the normal physiological range. We hypothesize that individual patient factor IX and X levels may be prognostic for susceptibility to circulating TF-induced thrombosis.

  11. EOP MIT General Circulation Model (MITgcm)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data contains a regional implementation of the Massachusetts Institute of Technology general circulation model (MITgcm) at a 1-km spatial resolution for the...

  12. [The analysis of tincture for improvement of blood circulation].

    Science.gov (United States)

    Bernatoniene, Rūta; Bernatoniene, Jurga; Ramanauskiene, Kristina

    2004-01-01

    The article describes qualitative and quantitative analysis of tincture for improvement of blood circulation. Flavonoids have been qualitatively determined by methods of thin-layer chromatography, high-pressure liquid chromatography and color reaction with magnesium powder and concentrated hydrochloric acid. Ferments were identified with ferric ammonium sulphate solution; glycosides--with dimethylaminobenzaldehyde solution in sulphur acid; saponin--with lead subacetate solution; reductive materials - with silver nitrate ammoniacal solution; albumen--with ninhydrin solution; and caffeic acid--by method of thin-layer chromatography. An optimal spectrophotometrical method for determining the quantity of quercetin was applied. The refractive index, relative density, loss of drying and ethanol concentration were determined according to European Pharmacopoeia Requirements.

  13. [Evaluation of the hypomagnetic environment effects on capillary blood circulation, blood pressure and heart rate].

    Science.gov (United States)

    Gurfinkel, Iu I; Vasin, A L; Matveeva, T A; Sasonko, M L

    2014-01-01

    Impact of attenuated magnetic field (MF) on human health is a hard-core issue of present-day cosmonautics. A series of experiments with animals exposed in attenuated MF revealed violent disorders in cardiovascular system development. Purpose of the work was to study effects of the hypomagnetic environment (HME) on capillary blood circulation, blood pressure (BP) and heart rate (HR) in normal people. Participants (n = 34) were 24 men and 10 women free from cardiovascular symptoms. Mean age was 43.3 +/- 15.4 years. Thirteen participants, i.e. 8 men and 5 women, were randomly selected for a repeated investigation in the usual conditions (imaginary exposure); mean age in the group made up 47.9 +/- 18 years. Cardiac rhythm and heart rate were recorded using cardiac monitor Astrocard (Russia). BP was measured with the help of automatic blood pressure monitor Tonocard (Russia). Capillary circulation was determined using a digital capillaroscope (Russia) with high-speed CMOS-camera (100 frames/s). Time of HME exposure was 60 min. It was demonstrated that in healthy people free from cardiovascular symptoms HME increases capillary circulation rate by 22.4% as compared with records made under the usual conditions. There was a reliable HR reduction by the end of HME exposure with reference to the measurements taken at the onset. At the end of exposure, diastolic BP dropped considerably relative to mid-exposure values and systolic BP, on the contrary, made a significant rise.

  14. Hindlimb-unloading suppresses B cell population in the bone marrow and peripheral circulation associated with OPN expression in circulating blood cells.

    Science.gov (United States)

    Ezura, Yoichi; Nagata, Junji; Nagao, Masashi; Hemmi, Hiroaki; Hayata, Tadayoshi; Rittling, Susan; Denhardt, David T; Noda, Masaki

    2015-01-01

    Rodent hindlimb unloading (HU) by tail-suspension is a model to investigate disuse-induced bone loss in vivo. Previously, we have shown that osteopontin (OPN, also known as Spp1) is required for unloading-induced bone loss. However, how unloading affects OPN expression in the body is not fully understood. Here, we examined OPN expression in peripheral blood of mice subjected to HU. Real-time RT-PCR analysis indicated that OPN expression is increased in circulating peripheral blood cells. This HU-induced increase in OPN mRNA expression was specific in circulating peripheral blood cells, as OPN was not increased in the blood cells in bone marrow. HU-induced enhancement in OPN expression in peripheral blood cells was associated with an increase in the fraction of monocyte/macrophage lineage cells in the peripheral blood. In contrast, HU decreased the fraction size of B-lymphocytes in the peripheral blood. We further examined if B-lymphogenesis is affected in the mice deficient for osteopontin subjected to HU. In bone marrow, HU decreased the population of the B-lymphocyte lineage cells significantly, whereas it did not alter the population of monocyte/macrophage lineage cells. HU also increased the cells in T-lymphocyte lineage in bone marrow. Interestingly, these changes were observed similarly both in OPN-deficient and wild-type mice. These results indicate for the first time that HU increases OPN expression in circulating cells and suppresses bone marrow B-lymphogenesis.

  15. Novel function for blood platelets and podoplanin in developmental separation of blood and lymphatic circulation.

    Science.gov (United States)

    Uhrin, Pavel; Zaujec, Jan; Breuss, Johannes M; Olcaydu, Damla; Chrenek, Peter; Stockinger, Hannes; Fuertbauer, Elke; Moser, Markus; Haiko, Paula; Fässler, Reinhard; Alitalo, Kari; Binder, Bernd R; Kerjaschki, Dontscho

    2010-05-13

    During embryonic development, lymph sacs form from the cardinal vein, and sprout centrifugally to form mature lymphatic networks. Separation of the lymphatic from the blood circulation by a hitherto unknown mechanism is essential for the homeostatic function of the lymphatic system. O-glycans on the lymphatic endothelium have recently been suggested to be required for establishment and maintenance of distinct blood and lymphatic systems, primarily by mediating proper function of podoplanin. Here, we show that this separation process critically involves platelet activation by podoplanin. We found that platelet aggregates build up in wild-type embryos at the separation zone of podoplanin(+) lymph sacs and cardinal veins, but not in podoplanin(-/-) embryos. Thus, podoplanin(-/-) mice develop a "nonseparation" phenotype, characterized by a blood-filled lymphatic network after approximately embryonic day 13.5, which, however, partially resolves in postnatal mice. The same embryonic phenotype is also induced by treatment of pregnant mice with acetyl salicylic acid, podoplanin-blocking antibodies, or by inactivation of the kindlin-3 gene required for platelet aggregation. Therefore, interaction of endothelial podoplanin of the developing lymph sac with circulating platelets from the cardinal vein is critical for separating the lymphatic from the blood vascular system.

  16. DEVELOPMENT OF WATER CIRCULATION MODEL INCLUDING IRRIGATION

    Science.gov (United States)

    Kotsuki, Shunji; Tanaka, Kenji; Kojiri, Toshiharu; Hamaguchi, Toshio

    It is well known that since agricultural water withdrawal has much affect on water circulation system, accurate analysis of river discharge or water balance are difficult with less regard for it. In this study, water circulation model composed of land surface model and distributed runoff model is proposed at 10km 10km resolution. In this model, irrigation water, which is estimated with land surface model, is introduced to river discharge analysis. The model is applied to the Chao Phraya River in Thailand, and reproduced seasonal water balance. Additionally, the discharge on dry season simulated with the model is improved as a result of including irrigation. Since the model, which is basically developed from global data sets, simulated seasonal change of river discharge, it can be suggested that our model has university to other river basins.

  17. A new torsion control mechanism induced by blood circulation in dragonfly wings.

    Science.gov (United States)

    Hou, Dan; Yin, Yajun; Zhong, Zheng; Zhao, Hongxiao

    2015-02-06

    A new mechanism to generate the torque of flapping dragonfly wings is disclosed in this paper. The concept is inspired by blood circulation in insect wings. The blood flowing in veins induces Coriolis forces in the flapping wings. The Coriolis forces acting on veins are of opposite directions when blood flows in and out. The opposite Coriolis forces generate torsional moment to the wing, especially in the leading-edge part. To estimate the time-varying torque induced by the blood circulation, a simplified U-tube model is designed. A three-dimensional finite element model of the wing is developed to analyze the dynamic behaviors under this torque. The dragonfly wing is in favor of torsional deformation because the corrugated structure is of high flexural rigidity in the spanwise direction but is of low torsional rigidity in the chordwise direction. In both the downstroke and upstroke, the twist of the leading-edge part causes the sections to camber spontaneously. Such a kind of deformation is found to be of great importance to improve aerodynamic efficiency. In addition, it also compensates for the disadvantageous bending deformation caused by air pressure in flapping flight. These results are important for better understanding of the multifunctional structures of dragonfly wings and may give some inspiration to the bionics of flapping-wing micro air vehicles (FMAVs).

  18. Effect of a deproteinized blood extract on the recovery of blood circulation in an ischaemic skin lesion.

    Science.gov (United States)

    Smahel, J.

    1982-01-01

    An experimental model was used to study the revascularization of an ischaemic skin lesion and the effect on this process of the blood extract Solcoseryl. Under the conditions given in the experiment, restoration of the circulation was by 2 modes--re-flow in the original vessels, and neovascularization. Solcoseryl given daily i.p. encouraged the re-flow phenomenon and therefore, by improving the microcirculation and nutrition, the healing of the ischaemic lesions. Images Fig. 1 Fig. 2 Fig. 3 Fig. 4 Fig. 5 Fig. 6 Fig. 7 Fig. 8 PMID:6176254

  19. Circulating microRNAs as biomarkers for detection of autologous blood transfusion.

    Directory of Open Access Journals (Sweden)

    Nicolas Leuenberger

    Full Text Available MicroRNAs (miRNAs are small non-coding RNAs that regulate various biological processes. Cell-free miRNAs measured in blood plasma have emerged as specific and sensitive markers of physiological processes and disease. In this study, we investigated whether circulating miRNAs can serve as biomarkers for the detection of autologous blood transfusion, a major doping technique that is still undetectable. Plasma miRNA levels were analyzed using high-throughput quantitative real-time PCR. Plasma samples were obtained before and at several time points after autologous blood transfusion (blood bag storage time 42 days in 10 healthy subjects and 10 controls without transfusion. Other serum markers of erythropoiesis were determined in the same samples. Our results revealed a distinct change in the pattern of circulating miRNAs. Ten miRNAs were upregulated in transfusion samples compared with control samples. Among these, miR-30b, miR-30c, and miR-26b increased significantly and showed a 3.9-, 4.0-, and 3.0-fold change, respectively. The origin of these miRNAs was related to pulmonary and liver tissues. Erythropoietin (EPO concentration decreased after blood reinfusion. A combination of miRNAs and EPO measurement in a mathematical model enhanced the efficiency of autologous transfusion detection through miRNA analysis. Therefore, our results lay the foundation for the development of miRNAs as novel blood-based biomarkers to detect autologous transfusion.

  20. Rapid multi-wavelength optical assessment of circulating blood volume without a priori data

    Science.gov (United States)

    Loginova, Ekaterina V.; Zhidkova, Tatyana V.; Proskurnin, Mikhail A.; Zharov, Vladimir P.

    2016-03-01

    The measurement of circulating blood volume (CBV) is crucial in various medical conditions including surgery, iatrogenic problems, rapid fluid administration, transfusion of red blood cells, or trauma with extensive blood loss including battlefield injuries and other emergencies. Currently, available commercial techniques are invasive and time-consuming for trauma situations. Recently, we have proposed high-speed multi-wavelength photoacoustic/photothermal (PA/PT) flow cytometry for in vivo CBV assessment with multiple dyes as PA contrast agents (labels). As the first step, we have characterized the capability of this technique to monitor the clearance of three dyes (indocyanine green, methylene blue, and trypan blue) in an animal model. However, there are strong demands on improvements in PA/PT flow cytometry. As additional verification of our proof-of-concept of this technique, we performed optical photometric CBV measurements in vitro. Three label dyes—methylene blue, crystal violet and, partially, brilliant green—were selected for simultaneous photometric determination of the components of their two-dye mixtures in the circulating blood in vitro without any extra data (like hemoglobin absorption) known a priori. The tests of single dyes and their mixtures in a flow system simulating a blood transfusion system showed a negligible difference between the sensitivities of the determination of these dyes under batch and flow conditions. For individual dyes, the limits of detection of 3×10-6 M‒3×10-6 M in blood were achieved, which provided their continuous determination at a level of 10-5 M for the CBV assessment without a priori data on the matrix. The CBV assessment with errors no higher than 4% were obtained, and the possibility to apply the developed procedure for optical photometric (flow cytometry) with laser sources was shown.

  1. Changes in blood-brain barrier function modify the neuroendocrine response to circulating substances.

    Science.gov (United States)

    Jezová, D; Johansson, B B; Oprsalová, Z; Vigas, M

    1989-04-01

    It is known that various experimental, pathological and even physiological situations may be accompanied by transient increases in blood-brain barrier (BBB) permeability. The hypothesis that under such conditions the blood-borne substances can reach the active sites in the brain in concentrations high enough to influence central control of hormone release was verified in these studies. A suitable experimental model of BBB opening by protamine sulfate administration in conscious rats was introduced. Using this model it was shown that the dopaminergic blocker domperidone inhibited apomorphine-induced ACTH release if permeability of the BBB was increased, but not under normal conditions. It is suggested that the changes in BBB function can modify the neuroendocrine response also to other circulating substances and this may be an important, until now unconsidered phenomenon in neuroendocrine research.

  2. Warm World Ocean Thermohaline Circulation Model

    Science.gov (United States)

    Zimov, N.; Zimov, S. A.

    2014-12-01

    Modern day ocean circulation is dominated by thermal convection with cold waters subsiding in the Northern Atlantic, filling the ocean interior with cold and heavy water. However, ocean circulation diminished during the last glaciation and consequently the downwelling of the cold. Therefore interior ocean water temperatures must have been affected by other mechanisms which are negligible in the current state. We propose that the submergence of highly saline water from warm seas with high rates of evaporation (like the Red or Mediterranean Sea) was a major factor controlling ocean circulation during the last glaciation. Even today, waters in these poorly connected seas are the heaviest waters in the World ocean (1.029 g/cm3). The second mechanism affecting ocean temperature is the geothermal heat flux. With no heat exchange between the atmosphere and the ocean, geothermal heat flux through the ocean floor is capable of increasing ocean temperature by tens of degrees C over a 100 thousand year glacial cycle. To support these hypotheses we present an ocean box model that describes thermohaline circulation in the World Ocean. According to the model parameters, all water circulation is driven by the water density gradient. Boxes include high-latitude seas, high salinity seas, surface ocean, glaciers, and rift and lateral zones of the ocean interior. External heat sources are radiative forcing, affected by Milankovich cycles, and geothermal heat flux. Additionally this model accounts for the heat produced by organic rain decay. Taking all input parameters close to currently observed values, the model manages to recreate the glacial-interglacial cycles. During the glacial periods only haline circulation takes place, the ocean is strongly stratified, and the interior ocean accumulates heat while high-latitudes accumulate ice. 112,000 years after glaciation starts, water density on the ocean bottom becomes equal to the density of water in high-latitude seas, strong thermal

  3. William Harvey and the discovery of the circulation of the blood

    Directory of Open Access Journals (Sweden)

    Ribatti Domenico

    2009-09-01

    Full Text Available Abstract This Commentary emphasizes the fundamental contribution of William Harvey to the discovery of the circulation of the blood and his scientific and experimental approach to this matter.

  4. [PULMONARY COMPLICATIONS IN CHILDREN, OPERATED ON FOR INBORN HEART FAILURES IN THE ARTIFICIAL BLOOD CIRCULATION ENVIRONMENT].

    Science.gov (United States)

    Moshkivska, L V; Nastenko, E A; Golovenko, O S; Lazoryshynets, V V

    2015-11-01

    The risk factors of pulmonary complications occurrence were analyzed in children, operated on for inborn heart failures in atrificial blood circulation environment. Pulmonary complications rate and the risk factors of their occurrence were analyzed.

  5. Parallel Computing of Ocean General Circulation Model

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    This paper discusses the parallel computing of the thirdgeneration Ocea n General Circulation Model (OGCM) from the State Key Laboratory of Numerical Mo deling for Atmospheric Science and Geophysical Fluid Dynamics(LASG),Institute of Atmosphere Physics(IAP). Meanwhile, several optimization strategies for paralle l computing of OGCM (POGCM) on Scalable Shared Memory Multiprocessor (S2MP) are presented. Using Message Passing Interface (MPI), we obtain super linear speedup on SGI Origin 2000 for parallel OGCM(POGCM) after optimization.

  6. Retro-orbital blood acquisition facilitates circulating microRNA measurement in zebrafish with paracetamol hepatotoxicity.

    Science.gov (United States)

    Vliegenthart, Adriaan D B; Starkey Lewis, Philip; Tucker, Carl S; Del Pozo, Jorge; Rider, Sebastein; Antoine, Daniel J; Dubost, Valérie; Westphal, Magdalena; Moulin, Pierre; Bailey, Matthew A; Moggs, Jonathan G; Goldring, Chris E; Park, B Kevin; Dear, James W

    2014-06-01

    Paracetamol is the commonest cause of acute liver failure in the Western world and biomarkers are needed that report early hepatotoxicity. The liver-enriched microRNA (miRNA), miR-122, is a promising biomarker currently being qualified in humans. For biomarker development and drug toxicity screening, the zebrafish has advantages over rodents; however, blood acquisition in this model remains technically challenging. We developed a method for collecting blood from the adult zebrafish by retro-orbital (RO) bleeding and compared it to the commonly used lateral incision method. The RO technique was more reliable in terms of the blood yield and minimum amount per fish. This new RO technique was used in a zebrafish model of paracetamol toxicity. Paracetamol induced dose-dependent increases in liver cell necrosis, serum alanine transaminase activity, and mortality. In situ hybridization localized expression of miR-122 to the cytoplasm of zebrafish hepatocytes. After collection by RO bleeding, serum miR-122 could be measured and this miRNA was substantially increased by paracetamol 24 h after exposure, an increase that was prevented by delayed (3 h poststart of paracetamol exposure) treatment with acetylcysteine. In summary, collection of blood by RO bleeding facilitated measurement of miR-122 in a zebrafish model of paracetamol hepatotoxicity. The zebrafish represents a new species for measurement of circulating miRNA biomarkers that are translational and can bridge between fish and humans.

  7. Systematic assessment of blood circulation time of functionalized upconversion nanoparticles in the chick embryo

    Science.gov (United States)

    Nadort, Annemarie; Liang, Liuen; Grebenik, Ekaterina; Guller, Anna; Lu, Yiqing; Qian, Yi; Goldys, Ewa; Zvyagin, Andrei

    2015-12-01

    Nanoparticle-based delivery of drugs and contrast agents holds great promise in cancer research, because of the increased delivery efficiency compared to `free' drugs and dyes. A versatile platform to investigate nanotechnology is the chick embryo chorioallantoic membrane tumour model, due to its availability (easy, cheap) and accessibility (interventions, imaging). In our group, we developed this model using several tumour cell lines (e.g. breast cancer, colon cancer). In addition, we have synthesized in-house silica coated photoluminescent upconversion nanoparticles with several functional groups (COOH, NH2, PEG). In this work we will present the systematic assessment of their in vivo blood circulation times. To this end, we injected chick embryos grown ex ovo with the functionalized UCNPs and obtained a small amount of blood at several time points after injection to create blood smears The UCNP signal from the blood smears was quantified using a modified inverted microscope imaging set-up. The results of this systematic study are valuable to optimize biochemistry protocols and guide nanomedicine advancement in the versatile chick embryo tumour model.

  8. Prolonged in vivo circulation time by zwitterionic modification of magnetite nanoparticles for blood pool contrast agents.

    Science.gov (United States)

    Xiao, Wangchuan; Lin, Jiang; Li, Mingli; Ma, Yongjie; Chen, Yuxin; Zhang, Chunfu; Li, Dan; Gu, Hongchen

    2012-01-01

    Long circulation time is critical for blood pool contrast agents used in high-resolution magnetic resonance angiography. For iron oxide particle contrast agents, size and surface properties significantly influence their in vivo performance. We developed a novel long-circulating blood pool contrast agent by introducing zwitterionic structure onto the particle surface. Zwitterionic structure was fabricated by 3-(diethylamino)propylamine (DEAPA) grafted onto the surface of ployacrylic acid coated magnetite nanoparticles via EDC/NHS [N-(3-dimethylaminopropyl)-N'-ethylcarbo-diimide hydrochloride/N-hydroxysuccinimide] coupling chemistry. Zwitterionic particles demonstrated five times lower macrophage cell uptake than the original particles and low cell toxicity. Magnetic resonance angiography indicated that zwitterionic nanoparticles had much longer in vivo circulation time than the original particles and were an ideal candidate for blood pool contrast agent. We suppose that zwitterionic modification by DEAPA and EDC/NHS can be used generally for coating nanoparticles with carboxyl surface and to prolong their circulating time.

  9. Arterial blood-pressure change and endogenous circulating substance P in man

    DEFF Research Database (Denmark)

    Henriksen, J H; Kastrup, J; Schaffalitzky De Muckadell, O B

    1985-01-01

    Substance P (SP) is a powerful vasodilator and this peptide is today considered to be a chemical messenger. The potential effects on circulating SP of acute changes in arterial blood-pressure was investigated in nine subjects. An increase in arterial mean blood-pressure (+33%, P less than 0.001, ...

  10. Circulation model for water circulation and purification in a water Cerenkov detector

    Institute of Scientific and Technical Information of China (English)

    LU Hao-Qi; YANG Chang-Gen; WANG Ling-Yu; XU Ji-Lei; WANG aui-Guang; WANG Zhi-Min; WANG Yi-Fang

    2009-01-01

    Owing to its low cost and good transparency, highly purified water is widely used as a medium in large water Cerenkov detector experiments. The water circulation and purification system is usually needed to keep the water in good quality. In this work, a practical circulation model is built to describe the variation of the water resistivity in the circulation process and compared with the data obtained from a prototype experiment. The successful test of the model makes it useful in the future design and optimization of the circulation/purification system.

  11. Modeling biomass gasification in circulating fluidized beds

    Science.gov (United States)

    Miao, Qi

    In this thesis, the modeling of biomass gasification in circulating fluidized beds was studied. The hydrodynamics of a circulating fluidized bed operating on biomass particles were first investigated, both experimentally and numerically. Then a comprehensive mathematical model was presented to predict the overall performance of a 1.2 MWe biomass gasification and power generation plant. A sensitivity analysis was conducted to test its response to several gasifier operating conditions. The model was validated using the experimental results obtained from the plant and two other circulating fluidized bed biomass gasifiers (CFBBGs). Finally, an ASPEN PLUS simulation model of biomass gasification was presented based on minimization of the Gibbs free energy of the reaction system at chemical equilibrium. Hydrodynamics plays a crucial role in defining the performance of gas-solid circulating fluidized beds (CFBs). A 2-dimensional mathematical model was developed considering the hydrodynamic behavior of CFB gasifiers. In the modeling, the CFB riser was divided into two regions: a dense region at the bottom and a dilute region at the top of the riser. Kunii and Levenspiel (1991)'s model was adopted to express the vertical solids distribution with some other assumptions. Radial distributions of bed voidage were taken into account in the upper zone by using Zhang et al. (1991)'s correlation. For model validation purposes, a cold model CFB was employed, in which sawdust was transported with air as the fluidizing agent. A comprehensive mathematical model was developed to predict the overall performance of a 1.2 MWe biomass gasification and power generation demonstration plant in China. Hydrodynamics as well as chemical reaction kinetics were considered. The fluidized bed riser was divided into two distinct sections: (a) a dense region at the bottom of the bed where biomass undergoes mainly heterogeneous reactions and (b) a dilute region at the top where most of homogeneous

  12. [The reaction of the pulpal blood circulation to thermal stimuli].

    Science.gov (United States)

    Gängler, P

    1976-01-01

    The present paper characterizes the reactions of the systemcirculation and microcirculation of the pulpa to the effects of temperature changes from--30 degrees C to +55 degrees C. In the range between 25 degrees C and 50 degrees C an increase of the blood flow rate can be observed. By long-standing action of temperatures above 40 degrees C and below 25 degrees C a dilatation of the blood vessels and a decrease of the blood flow rate are caused, thus leading to aggregations, capillary stoppage, and finally to thrombosis of entire pulpa sections. In addition to the outline of the critical initial alterations of the microcirculation in the course of inflammation the clinical conclusions towards crown and cavity preparation by means of water spray cooling, concerning thermal sensibility tests, and cryo-surgical operations are discussed.

  13. Effects of the Intermittent Pneumatic Circulator on Blood Pressure during Hemodialysis

    Directory of Open Access Journals (Sweden)

    Miao-Ju Hsu

    2010-11-01

    Full Text Available Hypotension is frequently reported during hemodialysis. This study aimed to examine the effect of the intermittent pneumatic circulator on blood pressure during hemodialysis. Sixteen subjects with chronic hemodialysis were recruited. Each subject randomly received two test conditions on separate days, hemodialysis with and without the circulator. The circulator was applied to the subject on lower extremities during 0.5–1 hr, 1.5–2 hr, 2.5–3 hr, and 3.5–4 hr of hemodialysis. Systolic and diastolic blood pressures (SBP and DBP and heart rate (HR were analyzed at pre-dialysis, 1 hr, 2 hr, and 3 hr of hemodialysis. Stroke volume (SV and cardiac output (CO were evaluated between 2.5 and 3.0 hr of hemodialysis. Blood chemicals (sodium, calcium, potassium, and phosphorous and Kt/V before and after each hemodialysis session were analyzed. The number of episodes of hypotension was also recorded. The circulator intervention significantly improved SBP and DBP across all time points (P = 0.002 for SBP; P = 0.002 for DBP. The frequency of hypotension was significantly decreased (P = 0.028. SV and CO were significantly improved with the circulator intervention (P = 0.017 for SV; P = 0.026 for CO and no statistical significances were found on blood chemicals or Kt/V analyses. The results suggested that the circulator intervention helps stabilize blood pressure and appears to be a practical treatment. Future studies are suggested to develop new circulator innovations with sensor feedback systems to enhance safety and maximize treatment efficiency.

  14. Climatology of the HOPE-G global ocean general circulation model - Sea ice general circulation model

    Energy Technology Data Exchange (ETDEWEB)

    Legutke, S. [Deutsches Klimarechenzentrum (DKRZ), Hamburg (Germany); Maier-Reimer, E. [Max-Planck-Institut fuer Meteorologie, Hamburg (Germany)

    1999-12-01

    The HOPE-G global ocean general circulation model (OGCM) climatology, obtained in a long-term forced integration is described. HOPE-G is a primitive-equation z-level ocean model which contains a dynamic-thermodynamic sea-ice model. It is formulated on a 2.8 grid with increased resolution in low latitudes in order to better resolve equatorial dynamics. The vertical resolution is 20 layers. The purpose of the integration was both to investigate the models ability to reproduce the observed general circulation of the world ocean and to obtain an initial state for coupled atmosphere - ocean - sea-ice climate simulations. The model was driven with daily mean data of a 15-year integration of the atmosphere general circulation model ECHAM4, the atmospheric component in later coupled runs. Thereby, a maximum of the flux variability that is expected to appear in coupled simulations is included already in the ocean spin-up experiment described here. The model was run for more than 2000 years until a quasi-steady state was achieved. It reproduces the major current systems and the main features of the so-called conveyor belt circulation. The observed distribution of water masses is reproduced reasonably well, although with a saline bias in the intermediate water masses and a warm bias in the deep and bottom water of the Atlantic and Indian Oceans. The model underestimates the meridional transport of heat in the Atlantic Ocean. The simulated heat transport in the other basins, though, is in good agreement with observations. (orig.)

  15. Snow hydrology in a general circulation model

    Science.gov (United States)

    Marshall, Susan; Roads, John O.; Glatzmaier, Gary

    1994-01-01

    A snow hydrology has been implemented in an atmospheric general circulation model (GCM). The snow hydrology consists of parameterizations of snowfall and snow cover fraction, a prognostic calculation of snow temperature, and a model of the snow mass and hydrologic budgets. Previously, only snow albedo had been included by a specified snow line. A 3-year GCM simulation with this now more complete surface hydrology is compared to a previous GCM control run with the specified snow line, as well as with observations. In particular, the authors discuss comparisons of the atmospheric and surface hydrologic budgets and the surface energy budget for U.S. and Canadian areas. The new snow hydrology changes the annual cycle of the surface moisture and energy budgets in the model. There is a noticeable shift in the runoff maximum from winter in the control run to spring in the snow hydrology run. A substantial amount of GCM winter precipitation is now stored in the seasonal snowpack. Snow cover also acts as an important insulating layer between the atmosphere and the ground. Wintertime soil temperatures are much higher in the snow hydrology experiment than in the control experiment. Seasonal snow cover is important for dampening large fluctuations in GCM continental skin temperature during the Northern Hemisphere winter. Snow depths and snow extent show good agreement with observations over North America. The geographic distribution of maximum depths is not as well simulated by the model due, in part, to the coarse resolution of the model. The patterns of runoff are qualitatively and quantitatively similar to observed patterns of streamflow averaged over the continental United States. The seasonal cycles of precipitation and evaporation are also reasonably well simulated by the model, although their magnitudes are larger than is observed. This is due, in part, to a cold bias in this model, which results in a dry model atmosphere and enhances the hydrologic cycle everywhere.

  16. Thirty-six Cases of Hyperglycemia Treated by Promoting Blood Circulation to Remove Stasis

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    @@Thirty-six cases with hyperglycemia were treated with the method of promoting blood circulation and removing stasis in a course of 4 weeks. The treatment was significantly effective in correcting the abnormal viscosity of the blood by reducing the contents of total plasmic cholesterol (TC), triglyceride (TG) and apoprotein B (apoB), while the level of the apoprotein A (apoA) was elevated.

  17. Device to determine the level of peripheral blood circulation and saturation

    Science.gov (United States)

    Kozlovska, Tetyana I.; Sander, Sergii V.; Zlepko, Sergii M.; Vasilenko, Valentina B.; Pavlov, Volodymyr S.; Dumenko, Victoria P.; Klapouschak, Andrii Yu.; Maciejewski, Marcin; DzierŻak, RóŻa; Surtel, Wojciech

    2016-09-01

    The paper evaluated the diagnostic value of laser photoplethysmography when examining patients with chronic lower limb ischemia. A statistical analysis of the research results was made, and diagrams of relationship between the degrees of ischemia and blood flow are presented. Development of the device to determine the level of peripheral blood circulation and saturation was presented. Also additional accessories in the form of optical fibers for different applications were suggested.

  18. NAO-ocean circulation interactions in a coupled general circulation model

    Energy Technology Data Exchange (ETDEWEB)

    Bellucci, A. [Centro Euro-Mediterraneo per i Cambiamenti Climatici, Bologna (Italy); Gualdi, S.; Navarra, A. [Centro Euro-Mediterraneo per i Cambiamenti Climatici, Bologna (Italy); Istituto Nazionale di Geofisica e Vulcanologia, Bologna (Italy); Scoccimarro, E. [Istituto Nazionale di Geofisica e Vulcanologia, Bologna (Italy)

    2008-12-15

    The interplay between the North Atlantic Oscillation (NAO) and the large scale ocean circulation is inspected in a twentieth century simulation conducted with a state-of-the-art coupled general circulation model. Significant lead-lag covariance between oceanic and tropospheric variables suggests that the system supports a damped oscillatory mode involving an active ocean-atmosphere coupling, with a typical NAO-like space structure and a 5 years timescale, qualitatively consistent with a mid-latitude delayed oscillator paradigm. The two essential processes governing the oscillation are (1) a negative feedback between ocean gyre circulation and the high latitude SST meridional gradient and (2) a positive feedback between SST and the NAO. The atmospheric NAO pattern appears to have a weaker projection on the ocean meridional overturning, compared to the gyre circulation, which leads to a secondary role for the thermohaline circulation in driving the meridional heat transport, and thus the oscillatory mode. (orig.)

  19. In situ tissue engineering of functional small-diameter blood vessels by host circulating cells only

    NARCIS (Netherlands)

    Talacua, Hanna; Smits, Anthal I P M; Muylaert, Dimitri E P; Van Rijswijk, Jan Willem; Vink, Aryan; Verhaar, Marianne C.; Driessen-Mol, Anita; Van Herwerden, Lex A.; Bouten, Carlijn V C; Kluin, Jolanda; Baaijens, Frank P T

    2015-01-01

    Inflammation is a natural phase of the wound healing response, which can be harnessed for the in situ tissue engineering of small-diameter blood vessels using instructive, bioresorbable synthetic grafts. This process is dependent on colonization of the graft by host circulating cells and subsequent

  20. Significant reduction in blood loss in patients undergoing minimal extracorporeal circulation

    NARCIS (Netherlands)

    Gerritsen, W. B.; van Boven, W. J.; Smelt, M.; Morshuis, W. J.; van Dongen, H. P.; Haas, F. J.; Aarts, L. P.

    2006-01-01

    Several recent studies have shown differences in blood loss and allogeneic transfusion requirements between on-pump and off-pump coronary artery bypass grafting (CABG). Recently a new concept, the mini-extracorporeal circulation, was introduced to minimize the side effects of extracorporeal circulat

  1. [Relationship between regulation effect of salvia miltiorrhiza on AQP2 in kidney and promoting blood circulation and diuresis].

    Science.gov (United States)

    Dong, Xiao-Jing; Guo, Liang-Feng; Yao, Rui; Xue, Song-Yan; Li, Feng

    2014-08-01

    Partial nature of "promoting blood circulation and dieresis" of Salvia Miltiorrhizain was initially demonstrated by investigating the regulation effect of AQP2 expression in kidney of trauma blood stasis model rats with the Salvia Miltiorrhizain so as to provide guidance for its clinical deployment of administration. Random allocation was taken to averagely divide 30 SD rats into two groups: 10 rats in normal group and 20 rats in blood stasis syndrome group. Trauma blood stasis rat model was established by quantitatively beating. Then the rat model group was divided into model group and salvia group. After 7 days of treatment, the rat kidney AQP2 expression was detected, the content of urine AQP2 was compared and the damaged local muscle and kidney pathological changes were observed by immunohistochemical method and western blot method. Compared with that of the normal group, rats in model group had inflammatory cells infiltration, blood stasis and edema of the injured local muscles and up-regulated AQP2 expression, decreasing urinary output, and kidney tissues blood stasis and edema (P diuresis" as the mechanism for the regulation effect of the salvia on AQP2 expression.

  2. Assessment of Blood Flow in Hepatocellular Carcinoma: Correlations of Computed Tomography Perfusion Imaging and Circulating Angiogenic Factors

    Directory of Open Access Journals (Sweden)

    Chen-Pin Chou

    2013-08-01

    Full Text Available Hepatocellular carcinoma (HCC is a highly vascular tumor through the process of angiogenesis. To evaluate more non-invasive techniques for assessment of blood flow (BF in HCC, this study examined the relationships between BF of HCC measured by computer tomography (CT perfusion imaging and four circulating angiogenic factors in HCC patients. Interleukin 6 (IL-6, interleukin 8 (IL-8, vascular endothelial growth factor (VEGF, and platelet derived growth factor (PDGF in plasma were measured using Bio-Plex multiplex immunoassay in 21 HCC patients and eight healthy controls. Circulating IL-6, IL-8 and VEGF showed higher concentrations in HCC patients than in controls (p < 0.05, and predicted HCC occurrence better than chance (p < 0.01. Twenty-one patients with HCC received 21-phase liver imaging using a 64-slice CT. Total BF, arterial BF, portal BF, arterial fraction (arterial BF/total BF of the HCC and surrounding liver parenchyma, and HCC-parenchyma ratio were measured using a dual-vessel model. After analyzing the correlations between BF in HCC and four circulating angiogenic factors, we found that the HCC-parenchyma ratio of arterial BF showed a significantly positive correlation with the level of circulating IL-8 (p < 0.05. This circulating biomarker, IL-8, provides a non-invasive tool for assessment of BF in HCC.

  3. Conceptual models of the wind-driven and thermohaline circulation

    NARCIS (Netherlands)

    Drijfhout, S.S.; Marshall, D.P.; Dijkstra, H.A.

    2013-01-01

    Conceptual models are a vital tool for understanding the processes that maintain the global ocean circulation, both in nature and in complex numerical ocean models. In this chapter we provide a broad overview of our conceptual understanding of the wind-driven circulation, the thermohaline circulatio

  4. Circular pump support of blood circulation in the human body

    Science.gov (United States)

    Medvedev, A. E.; Fomin, V. M.; Prikhodko, Yu. M.; Cherniavskiy, A. M.; Fomichev, V. P.; Fomichev, A. V.; Chekhov, V. P.; Ruzmatov, T. M.

    2016-10-01

    The need of circulatory support systems in the treatment of chronic heart failure is increasing constantly, as 20% of patients in the waiting list die every year. Despite the great need for mechanical heart support systems, using of available systems is limited by the expensiveness. In addition, there is no one system that is 100% responsible to all medical and technical requirements, and would be completely safe for patient. Therefore, further research in the field of circu-latory support systems, considering health and technical requirements is relevant. One of the new directions in the study are disc pumps of viscous friction for liquid transporting, based on the Tesla pump principle. The operation principle of pumps based on the phenomenon of the boundary layer which is formed on the disk rotating in a fluid. There are experimental studies results of models with different variants of the rotor suspension, the various forms and the number of disks, forms the pump housing. However, none of the above samples was not brought to clinical trials. Furthermore, despite the promise of this model is still used today in some circulatory support systems are no similar type pump. Published data provide a basis for further development and testing of the pump model and allow to hope for leveling a number of significant shortcomings of modern left ventricular bypass systems.

  5. BIM-enabled Conceptual Modelling and Representation of Building Circulation

    Directory of Open Access Journals (Sweden)

    Jin Kook Lee

    2014-08-01

    Full Text Available This paper describes how a building information modelling (BIM-based approach for building circulation enables us to change the process of building design in terms of its computational representation and processes, focusing on the conceptual modelling and representation of circulation within buildings. BIM has been designed for use by several BIM authoring tools, in particular with the widely known interoperable industry foundation classes (IFCs, which follow an object-oriented data modelling methodology. Advances in BIM authoring tools, using space objects and their relations defined in an IFC’s schema, have made it possible to model, visualize and analyse circulation within buildings prior to their construction. Agent-based circulation has long been an interdisciplinary topic of research across several areas, including design computing, computer science, architectural morphology, human behaviour and environmental psychology. Such conventional approaches to building circulation are centred on navigational knowledge about built environments, and represent specific circulation paths and regulations. This paper, however, places emphasis on the use of ‘space objects’ in BIM-enabled design processes rather than on circulation agents, the latter of which are not defined in the IFCs’ schemas. By introducing and reviewing some associated research and projects, this paper also surveys how such a circulation representation is applicable to the analysis of building circulation-related rules.

  6. A model for red blood cells in simulations of large-scale blood flows

    CERN Document Server

    Melchionna, Simone

    2011-01-01

    Red blood cells (RBCs) are an essential component of blood. A method to include the particulate nature of blood is introduced here with the goal of studying circulation in large-scale realistic vessels. The method uses a combination of the Lattice Boltzmann method (LBM) to account for the plasma motion, and a modified Molecular Dynamics scheme for the cellular motion. Numerical results illustrate the quality of the model in reproducing known rheological properties of blood as much as revealing the effect of RBC structuring on the wall shear stress, with consequences on the development of cardiovascular diseases.

  7. It Is All in the Blood: The Multifaceted Contribution of Circulating Progenitor Cells in Diabetic Complications

    Directory of Open Access Journals (Sweden)

    Gian Paolo Fadini

    2012-01-01

    Full Text Available Diabetes mellitus (DM is a worldwide growing disease and represents a huge social and healthcare problem owing to the burden of its complications. Micro- and macrovascular diabetic complications arise from excess damage through well-known biochemical pathways. Interestingly, microangiopathy hits the bone marrow (BM microenvironment with features similar to retinopathy, nephropathy and neuropathy. The BM represents a reservoir of progenitor cells for multiple lineages, not limited to the hematopoietic system and including endothelial cells, smooth muscle cells, cardiomyocytes, and osteogenic cells. All these multiple progenitor cell lineages are profoundly altered in the setting of diabetes in humans and animal models. Reduction of endothelial progenitor cells (EPCs along with excess smooth muscle progenitor (SMP and osteoprogenitor cells creates an imbalance that promote the development of micro- and macroangiopathy. Finally, an excess generation of BM-derived fusogenic cells has been found to contribute to diabetic complications in animal models. Taken together, a growing amount of literature attributes to circulating progenitor cells a multi-faceted role in the pathophysiology of DM, setting a novel scenario that puts BM and the blood at the centre of the stage.

  8. Holographic intravital microscopy for 2-D and 3-D imaging intact circulating blood cells in microcapillaries of live mice

    Science.gov (United States)

    Kim, Kyoohyun; Choe, Kibaek; Park, Inwon; Kim, Pilhan; Park, Yongkeun

    2016-09-01

    Intravital microscopy is an essential tool that reveals behaviours of live cells under conditions close to natural physiological states. So far, although various approaches for imaging cells in vivo have been proposed, most require the use of labelling and also provide only qualitative imaging information. Holographic imaging approach based on measuring the refractive index distributions of cells, however, circumvent these problems and offer quantitative and label-free imaging capability. Here, we demonstrate in vivo two- and three-dimensional holographic imaging of circulating blood cells in intact microcapillaries of live mice. The measured refractive index distributions of blood cells provide morphological and biochemical properties including three-dimensional cell shape, haemoglobin concentration, and haemoglobin contents at the individual cell level. With the present method, alterations in blood flow dynamics in live healthy and sepsis-model mice were also investigated.

  9. Holographic intravital microscopy for 2-D and 3-D imaging intact circulating blood cells in microcapillaries of live mice

    CERN Document Server

    Kim, Kyoohyun; Park, Inwon; Kim, Pilhan; Park, YongKeun

    2016-01-01

    Intravital microscopy is an essential tool that reveals behaviours of live cells under conditions close to natural physiological states. So far, although various approaches for imaging cells in vivo have been proposed, most require the use of labelling and also provide only qualitative imaging information. Holographic imaging approach based on measuring the refractive index distributions of cells, however, circumvent these problems and offer quantitative and label-free imaging capability. Here, we demonstrate in vivo two- and three-dimensional holographic imaging of circulating blood cells in intact microcapillaries of live mice. The measured refractive index distributions of blood cells provide morphological and biochemical properties including three-dimensional cell shape, haemoglobin concentration, and haemoglobin contents at the individual cell level. With the present method, alterations in blood flow dynamics in live healthy and sepsis-model mouse were also investigated.

  10. Multivariate autoregressive modelling combined with transcephalic electrical impedance: method to relate neonatal systemic circulation and respiration to cerebral circulation.

    Science.gov (United States)

    Grönlund, J U; Jalonen, J; Korhonen, I; Rolfe, P; Välimäki, I A

    1995-05-01

    We studied the pulsatile component of cerebral circulation with transcephalic electrical impedance (delta Z) in six preterm newborns, three of whom had severe cerebral bleeding, peri-intraventricular haemorrhage (PIVH). The transcephalic electrical impedance delta Z signal, ECG, arterial blood pressure, (aBP) and respirogram were recorded on analogue magnetic tape for 30 min. Artefact-free stationary segments (lasting for 2 min) of the four signals were digitised. A digital multivariate autoregressive (MAR) model was used to study frequency-specific variability in the signals and to quantify interrelations between the variabilities of delta Z, HR, aBP and respiratory signals. MAR modelling describes a system where all the signals simultaneously explain each other. The inherent variability of delta Z was lower and the influences of respiration and aBP on delta Z significantly greater in infants with severe PIVH than in controls. These changes were observed at high frequencies corresponding to respiration and heart rate. This may be interpreted as a marker of pressure passivism in the cerebral circulation following PIVH. We conclude that in preterm babies the application of MAR modelling, together with transcephalic impedance, may be a new, helpful and quantitative method for the study of simultaneous interrelations between variables of cerebral and systemic circulations and respiration.

  11. Seasonal overturning circulation in the Red Sea: 1. Model validation and summer circulation

    KAUST Repository

    Yao, Fengchao

    2014-04-01

    The overturning circulation in the Red Sea exhibits a distinct seasonally reversing pattern and is studied using high-resolution MIT general circulation model simulations. In the first part of this study, the vertical and horizontal structure of the summer overturning circulation and its dynamical mechanisms are presented from the model results. The seasonal water exchange in the Strait of Bab el Mandeb is successfully simulated, and the structures of the intruding subsurface Gulf of Aden intermediate water are in good agreement with summer observations in 2011. The model results suggest that the summer overturning circulation is driven by the combined effect of the shoaling of the thermocline in the Gulf of Aden resulting from remote winds in the Arabian Sea and an upward surface slope from the Red Sea to the Gulf of Aden set up by local surface winds in the Red Sea. In addition, during late summer two processes associated, respectively, with latitudinally differential heating and increased salinity in the southern Red Sea act together to cause the reversal of the contrast of the vertical density structure and the cessation of the summer overturning circulation. Dynamically, the subsurface northward pressure gradient force is mainly balanced by vertical viscosity resulting from the vertical shear and boundary friction in the Strait of Bab el Mandeb. Unlike some previous studies, the three-layer summer exchange flows in the Strait of Bab el Mandeb do not appear to be hydraulically controlled.

  12. Changes in circulating blood volume after infusion of hydroxyethyl starch 6% in critically ill patients

    DEFF Research Database (Denmark)

    Christensen, P; Andersson, J; Rasmussen, S E;

    2001-01-01

    The cardiovascular response to a volume challenge with hydroxyethyl starch (HES) (200/0.5) 6% depends on the relation between the volume of HES 6% infused and the expansion of the blood volume in critically ill patients. However, only relatively limited data exist on the plasma expanding effect...... of infusion of HES 6% in critically ill patients. The purpose of the study was to evaluate the variation in the expansion of the circulating blood volume (CBV) in critically ill patients after infusion of 500 ml of colloid (HES (200/0.5) 6%) using the carbon monoxide method....

  13. Hemodynamic modeling of the intrarenal circulation.

    Science.gov (United States)

    M'rabet Bensalah, K; Uehlinger, D; Kalicki, R; Czerwinska, J

    2013-12-01

    Three dimensional, time dependent numerical simulations of healthy and pathological conditions in a model kidney were performed. Blood flow in a kidney is not commonly investigated by computational approach, in contrast for example, to the flow in a heart. The flow in a kidney is characterized by relatively small Reynolds number (100 laminar regime). The presented results give insight into the structure of such flow, which is hard to measure in vivo. The simulations have suggested that venous thrombosis is more likely than arterial thrombosis-higher shear rate observed. The obtained maximum velocity, as a result of the simulations, agrees with the observed in vivo measurements. The time dependent simulations show separation regimes present in the vicinity of the maximum pressure value. The pathological constriction introduced to the arterial geometry leads to the changes in separation structures. The constriction of a single vessel affects flow in the whole kidney. Pathology results in different flow rate values in healthy and affected branches, as well as, different pulsate cycle characteristic for the whole system.

  14. Platelet proteomics and its advanced application for research of blood stasis syndrome and activated blood circulation herbs of Chinese medicine.

    Science.gov (United States)

    Liu, Yue; Yin, Huijun; Chen, Keji

    2013-11-01

    The development of novel and efficient antiplatelet agents that have few adverse effects and methods that improve antiplatelet resistance has long been the focus of international research on the prevention and treatment of cardiovascular and cerebrovascular diseases. Recent advances in platelet proteomics have provided a technology platform for high-quality research of platelet pathophysiology and the development of new antiplatelet drugs. The study of blood stasis syndrome (BSS) and activated blood circulation of traditional Chinese medicine (TCM) is one of the most active fields where the integration of TCM and western medicine in China has been successful. Activated blood circulation herbs (ABC herbs) of Chinese medicine are often used in the treatment of BSS. Most ABC herbs have antiplatelet and anti-atherosclerosis activity, but knowledge about their targets is lacking. Coronary heart disease (CHD), BSS, and platelet activation are closely related. By screening and identifying activated platelet proteins that are differentially expressed in BSS of CHD, platelet proteomics has helped researchers interpret the antiplatelet mechanism of action of ABC herbs and provided many potential biomarkers for BSS that could be used to evaluate the clinical curative effect of new antiplatelet drugs. In this article the progress of platelet proteomics and its advanced application for research of BSS and ABC herbs of Chinese medicine are reviewed.

  15. Correcting circulation biases in a lower-resolution global general circulation model with data assimilation

    Science.gov (United States)

    Canter, Martin; Barth, Alexander; Beckers, Jean-Marie

    2017-02-01

    In this study, we aim at developing a new method of bias correction using data assimilation. This method is based on the stochastic forcing of a model to correct bias by directly adding an additional source term into the model equations. This method is presented and tested first with a twin experiment on a fully controlled Lorenz '96 model. It is then applied to the lower-resolution global circulation NEMO-LIM2 model, with both a twin experiment and a real case experiment. Sea surface height observations are used to create a forcing to correct the poorly located and estimated currents. Validation is then performed throughout the use of other variables such as sea surface temperature and salinity. Results show that the method is able to consistently correct part of the model bias. The bias correction term is presented and is consistent with the limitations of the global circulation model causing bias on the oceanic currents.

  16. Correcting circulation biases in a lower-resolution global general circulation model with data assimilation

    Science.gov (United States)

    Canter, Martin; Barth, Alexander; Beckers, Jean-Marie

    2016-12-01

    In this study, we aim at developing a new method of bias correction using data assimilation. This method is based on the stochastic forcing of a model to correct bias by directly adding an additional source term into the model equations. This method is presented and tested first with a twin experiment on a fully controlled Lorenz '96 model. It is then applied to the lower-resolution global circulation NEMO-LIM2 model, with both a twin experiment and a real case experiment. Sea surface height observations are used to create a forcing to correct the poorly located and estimated currents. Validation is then performed throughout the use of other variables such as sea surface temperature and salinity. Results show that the method is able to consistently correct part of the model bias. The bias correction term is presented and is consistent with the limitations of the global circulation model causing bias on the oceanic currents.

  17. Particle-based methods for multiscale modeling of blood flow in the circulation and in devices: challenges and future directions. Sixth International Bio-Fluid Mechanics Symposium and Workshop March 28-30, 2008 Pasadena, California.

    Science.gov (United States)

    Yamaguchi, Takami; Ishikawa, Takuji; Imai, Y; Matsuki, N; Xenos, Mikhail; Deng, Yuefan; Bluestein, Danny

    2010-03-01

    A major computational challenge for a multiscale modeling is the coupling of disparate length and timescales between molecular mechanics and macroscopic transport, spanning the spatial and temporal scales characterizing the complex processes taking place in flow-induced blood clotting. Flow and pressure effects on a cell-like platelet can be well represented by a continuum mechanics model down to the order of the micrometer level. However, the molecular effects of adhesion/aggregation bonds are on the order of nanometer. A successful multiscale model of platelet response to flow stresses in devices and the ensuing clotting responses should be able to characterize the clotting reactions and their interactions with the flow. This paper attempts to describe a few of the computational methods that were developed in recent years and became available to researchers in the field. They differ from traditional approaches that dominate the field by expanding on prevailing continuum-based approaches, or by completely departing from them, yielding an expanding toolkit that may facilitate further elucidation of the underlying mechanisms of blood flow and the cellular response to it. We offer a paradigm shift by adopting a multidisciplinary approach with fluid dynamics simulations coupled to biophysical and biochemical transport.

  18. A novel liposome surface modification agent that prolongs blood circulation and retains surface ligand reactivity.

    Science.gov (United States)

    Ishihara, Atsushi; Yamauchi, Masahiro; Tsuchiya, Tomoko; Mimura, Yukiteru; Tomoda, Yutaka; Katagiri, Ayato; Kamiya, Masaaki; Nemoto, Hisao; Suzawa, Toshiyuki; Yamasaki, Motoo

    2012-01-01

    Liposomes are recognized as potentially useful drug carriers but many problems preclude practical medical application. Liposomes bind with serum proteins (opsonization) and are captured by the reticuloendothelial system cells in the liver and spleen, which limits their ability to deliver drugs to other target sites. Modification of lipids with flexible, hydrophilic polymers such as poly(ethylene glycol) (PEG) to yield sterically stabilized liposomes is one approach to improve liposome blood circulation and tissue distribution properties. In this study, we examined liposomes prepared using lipids modified with a new branched oligoglycerol (BGL) moiety for steric stabilization. This novel BGL comprised 14 glycerol units (termed BGL014) connected with flexible ether linkages, resulting in a branched cascade-like structure that is highly expanded in aqueous solution. BGL014 was coupled to 1,2-distearoylphosphatidylethanolamine to yield BGL014-modified lipids. Incorporation of BGL014 into liposomes (BGL014L) resulted in long blood circulation times, despite a much thinner fixed aqueous layer thickness compared to PEG formulations. BGL014 produced a liposome surface coating that appears to function through steric inhibition of non-specific protein binding without strong interference of specific protein-binding reactions. Liposome structure and functionality was maintained following BGL014-modification, as the incorporation ratio of drug remained high. These results suggest that the BGL014 modification of liposomes is a promising approach to produce stable and long circulating drug carriers capable of selective binding to specific proteins.

  19. Modelling the Seasonal Overturning Circulation in the Red Sea

    KAUST Repository

    Yao, Fengchao

    2015-04-01

    The overturning circulation in the Red Sea exhibits a distinct seasonally reversing pattern and is studied using 50-year, high-resolution MIT general circulation model simulations. The seasonal water exchange in the Strait of Bab el Mandeb is successfully simulated, and the structures of the intruding subsurface Gulf of Aden intermediate water are in good agreement with summer observations in 2011. The model results suggest that the summer overturning circulation is driven by the combined effect of the shoaling of the thermocline in the Gulf of Aden resulting from remote winds in the Arabian Sea and an upward surface slope from the Red Sea to the Gulf of Aden set up by local surface winds in the Red Sea. For the winter overturning circulation, the climatological model mean results suggest that the surface inflow intensifies in a western boundary current in the southern Red Sea that switches to an eastern boundary current north of 24°N. The overturning is accomplished through a cyclonic recirculation and a cross-basin overturning circulation in the northern Red Sea, with major sinking occurring along a narrow band of width about 20 km along the eastern boundary and weaker upwelling along the western boundary. The northward pressure gradient force, strong vertical mixing, and horizontal mixing near the boundary are the essential dynamical components in the model\\'s winter overturning circulation.

  20. Repercussões do pneumoperitônio sobre o sistema venoso dos membros inferiores-estudo em porcas The effect of pneumoperitoneum in the blood circulation of the lower limbs-a swine model

    Directory of Open Access Journals (Sweden)

    Antonio Carlos Valezi

    1999-02-01

    Full Text Available A trombose venosa profunda e a embolia pulmonar são complicações dos atos cirúrgicos nem sempre diagnosticadas. Nas operações pela via laparoscópica, a insuflação do CO2 na cavidade peritoneal é provavelmente a principal determinante da estase venosa nos membros inferiores. Este trabalho foi realizado com a finalidade de determinar a influência do pneumoperitônio na dinâmica circulatória dos membros inferiores. Distribuíram-se trinta porcas em três grupos: sem pneumoperitônio, com pneumoperitônio de 10mmHg e de l5mmHg de pressão intra-abdominal. Foram medidas a freqüência e débito cardíacos, pressão arterial média, pressão e diâmetro da artéria e veia femorais, velocidade do fluxo arterial e venoso femorais. Após a realização do pneumoperitônio foi encontrado aumento significativo na pressão e no diâmetro da veia femoral e diminuição significativa na velocidade do fluxo venoso femoral. A elevação da pressão venosa femoral e a diminuição da velocidade do fluxo venoso femoral foram mais intensas com o aumento da pressão intra-abdominal. Todos os parâmetros analisados retornaram aos valores iniciais após o esvaziamento do pneumoperitônio.Deep venous thrombosis and pulmonary embolism are complications of surgical procedures, the most of times underdiagnosticated. ln laparoscopic surgery, the carbon dioxide insuflation into the peritoneal cavity is probably the cause of venous stasis of the lower limbs. The purpose of this study was to verify the effects of pneumoperitoneum in the blood circulation of the lower limbs. Thirty female pigs were divided in three groups: 1- without pneumoperitoneum; I - with 10 mmHg; and II - with 15 mmHg of abdominal pressure levels. Within the clinical parameters were analysed heart rate, cardiac output and mean arterial pressure to certify that the haemodynamic changes would not be gilty for the modifications of lower limbs circulation. This analysis did not find significant

  1. A new barotropic model of the wind-driven circulation

    Institute of Scientific and Technical Information of China (English)

    张庆华; 曲媛媛; 李坚克

    1999-01-01

    Rationalized by the observational circulation pattern in the upper ocean of the North Pacific, meridional friction term is first incorporated in a barotropic theoretical model of the wind-driven circulation. The governing potential vortieity equation thence has β term and wind stress curl term (the two of the Sverdrup balance), zonal friction term and meridional friction term. The analytical solution satisfactorily captures many important features of the wind-driven circulation in the North Pacific: Kuroshio, Oyashio, Kuroshio extension, North Equatorial Current, and especially the eastern boundary currents in the North Pacific, i.e. California current and Alaska current.

  2. [The unfolding of the blood circulation doctrine: the correspondence between William Harvey and Caspar Hofmann in May 1636].

    Science.gov (United States)

    Rebollo, Regina André

    2002-01-01

    The present article analyzes the letters exchanged by Caspar Hofmann and William Harvey in 1636 and the delineation of the main questions and answers on the blood circulation theory. The first part of the article presents concepts about blood circulation according to the time's physiology; the second part presents the changes introduced by Harvey; the third and last part presents the debate between Hofmann and Harvey.

  3. Action of adrenalin on the circulation of the murine Plasmodium developing stages, in different blood compartments

    Directory of Open Access Journals (Sweden)

    Bertani S.

    2004-12-01

    Full Text Available Adrenalin was used to investigate in vivo the circulation of the different stages of rodent Plasmodium present in the blood. A single dose of adrenalin injected to mice infected with P. yoelii resulted immediately in i a diminution of the parasitaemia of approximately 50 % in the peripheral large vessels (estimated in tail blood films, as well as in the capillaries (estimated in smears of blood collected from a fed Anopheles, and ii an increased parasitaemia in blood collected by cardiac puncture from the right heart. The numbers of young stages of P. yoelii in the peripheral blood were initially somewhat reduced but, unexpectedly, midterm trophozoites were preferentially expelled from the peripheral blood into major organs like the heart. With P. vinckei, parasitaemia decreased only when midterm trophozoites predominated, and with P. chabaudi no effect was observed at any time. We propose that midterm trophozoites, by their increased surface area, as compared to rings, and their flexibility which contrasts with the rigid schizonts, are particularly susceptible to haemodynamic perturbations.

  4. Twentieth century Walker Circulation change: data analysis and model experiments

    Energy Technology Data Exchange (ETDEWEB)

    Meng, Qingjia [Leibniz-Institut fuer Meereswissenschaften, Kiel (Germany); Chinese Research Academy of Environmental Sciences, River and Coastal Environment Research Center, Beijing (China); Chinese Academy of Sciences, Key Laboratory of Ocean Circulation and Waves, Institute of Oceanology, Qingdao (China); Latif, Mojib; Park, Wonsun; Keenlyside, Noel S.; Martin, Thomas [Leibniz-Institut fuer Meereswissenschaften, Kiel (Germany); Semenov, Vladimir A. [Leibniz-Institut fuer Meereswissenschaften, Kiel (Germany); A.M. Obukhov Institute of Atmospheric Physics, Russian Academy of Sciences, Moscow (Russian Federation)

    2012-05-15

    Recent studies indicate a weakening of the Walker Circulation during the twentieth century. Here, we present evidence from an atmospheric general circulation model (AGCM) forced by the history of observed sea surface temperature (SST) that the Walker Circulation may have intensified rather than weakened. Observed Equatorial Indo-Pacific Sector SST since 1870 exhibited a zonally asymmetric evolution: While the eastern part of the Equatorial Pacific showed only a weak warming, or even cooling in one SST dataset, the western part and the Equatorial Indian Ocean exhibited a rather strong warming. This has resulted in an increase of the SST gradient between the Maritime Continent and the eastern part of the Equatorial Pacific, one driving force of the Walker Circulation. The ensemble experiments with the AGCM, with and without time-varying external forcing, suggest that the enhancement of the SST gradient drove an anomalous atmospheric circulation, with an enhancement of both Walker and Hadley Circulation. Anomalously strong precipitation is simulated over the Indian Ocean and anomalously weak precipitation over the western Pacific, with corresponding changes in the surface wind pattern. Some sensitivity to the forcing SST, however, is noticed. The analysis of twentieth century integrations with global climate models driven with observed radiative forcing obtained from the Coupled Model Intercomparison Project (CMIP) database support the link between the SST gradient and Walker Circulation strength. Furthermore, control integrations with the CMIP models indicate the existence of strong internal variability on centennial timescales. The results suggest that a radiatively forced signal in the Walker Circulation during the twentieth century may have been too weak to be detectable. (orig.)

  5. Detection of Circulating Tumour Cells from Blood of Breast Cancer Patients via RT-qPCR

    Energy Technology Data Exchange (ETDEWEB)

    Andergassen, Ulrich; Kölbl, Alexandra C.; Hutter, Stefan; Friese, Klaus; Jeschke, Udo, E-mail: udo.jeschke@med.uni-muenchen.de [Department of Obstetrics and Gynaecology, Ludwig Maximilians University of Munich, Munich, Maistrasse 11, D-80337 Munich (Germany)

    2013-09-25

    Breast cancer is still the most frequent cause of cancer-related death in women worldwide. Often death is not caused only by the primary tumour itself, but also by metastatic lesions. Today it is largely accepted, that these remote metastases arise out of cells, which detach from the primary tumour, enter circulation, settle down at secondary sites in the body and are called Circulating Tumour Cells (CTCs). The occurrence of such minimal residual diseases in the blood of breast cancer patients is mostly linked to a worse prognosis for therapy outcome and overall survival. Due to their very low frequency, the detection of CTCs is, still a technical challenge. RT-qPCR as a highly sensitive method could be an approach for CTC-detection from peripheral blood of breast cancer patients. This assumption is based on the fact that CTCs are of epithelial origin and therefore express a different gene panel than surrounding blood cells. For the technical approach it is necessary to identify appropriate marker genes and to correlate their gene expression levels to the number of tumour cells within a sample in an in vitro approach. After that, samples from adjuvant and metastatic patients can be analysed. This approach may lead to new concepts in diagnosis and treatment.

  6. The Donders model of the circulation in normo- and pathophysiology

    DEFF Research Database (Denmark)

    Noordergraaf, Gerrit J.; Ottesen, Johnny T.; Kortsmit, Wil J.P.M.

    2006-01-01

    the continuum of physiological conditions to cardiopulmonary resuscitation effects within the circulation.   Within the model, Harvey's view of the circulation has been broadened to include impedance-defined flow as a unifying concept. The cardiac function curve, the relation between ventricular filling...... and output, changes during exercise. First, it rotates counterclockwise and stretches along the output axis, second, it shifts along the filling axis. The first is induced by sympathetic control, the second by respiratory control. The model shows that depth of respiration, sympathetic stimulation of cardiac......A model of the closed human cardiovascular loop is developed. This model, using one set of 88 equations, allows variations from normal resting conditions to exercise, as well as to the extreme condition of a circulation following cardiac arrest. The principal purpose of the model is to evaluate...

  7. Modelling circulating tumour cells for personalised survival prediction in metastatic breast cancer.

    Directory of Open Access Journals (Sweden)

    Gianluca Ascolani

    2015-05-01

    Full Text Available Ductal carcinoma is one of the most common cancers among women, and the main cause of death is the formation of metastases. The development of metastases is caused by cancer cells that migrate from the primary tumour site (the mammary duct through the blood vessels and extravasating they initiate metastasis. Here, we propose a multi-compartment model which mimics the dynamics of tumoural cells in the mammary duct, in the circulatory system and in the bone. Through a branching process model, we describe the relation between the survival times and the four markers mainly involved in metastatic breast cancer (EPCAM, CD47, CD44 and MET. In particular, the model takes into account the gene expression profile of circulating tumour cells to predict personalised survival probability. We also include the administration of drugs as bisphosphonates, which reduce the formation of circulating tumour cells and their survival in the blood vessels, in order to analyse the dynamic changes induced by the therapy. We analyse the effects of circulating tumour cells on the progression of the disease providing a quantitative measure of the cell driver mutations needed for invading the bone tissue. Our model allows to design intervention scenarios that alter the patient-specific survival probability by modifying the populations of circulating tumour cells and it could be extended to other cancer metastasis dynamics.

  8. Diagnostics And Treatment Of Patients With Blood Circulation Insufficiency In Vertebrobasilar Bed

    Directory of Open Access Journals (Sweden)

    A.M. Khachatryan

    2009-12-01

    Full Text Available For improvement of treatment results of patients with vertebrobasilar insufficiency we have analyzed data of medical examination and treatment of 182 patients stayed in clinics of Hospital Surgery and Nervous System Diseases from the 1st of January of 2005 till the 30th of June of 2009. Method of screening diagnostics, quantitative and qualitative blood flow estimation by means of Doppler ultrasonic investigation and angiography have been performed. The cause of blood circulation insufficiency in the vertebrobasilar bed at 87 patients was vertebral artery syndrome and in 95 cases there were the significant hemodynamical damages of blood flow in aorta arch branches and intracranial arteries. The neuroangiotropic therapy has been made for all patients, but the clinical improvement period was short in most cases, more prolonged effect was observed in addition of conservative therapy with plasmapheresis by indications. In the complex treatment of patients with vertebrobasilar insufficiency accompanied by degenerative diseases of spine chemical sympathectomy of vertebral artery in the III segment in the form of procaine and spirit-procaine blockades was made in 116 and 69 cases accordingly. The surgical sympathectomy was made in 15 patients. The surgical operations were made in 62 of 95 patients with significant hemodynamic pathology of blood flow in the vertebrobasilar region. In most cases isolative and combinative reconstructive surgery on carotid arteries was carried out. It played a significant role in blood flow correction. Favorable postoperative results were observed in most cases (93, 5%

  9. Application of Improved Radiation Modeling to General Circulation Models

    Energy Technology Data Exchange (ETDEWEB)

    Michael J Iacono

    2011-04-07

    This research has accomplished its primary objectives of developing accurate and efficient radiation codes, validating them with measurements and higher resolution models, and providing these advancements to the global modeling community to enhance the treatment of cloud and radiative processes in weather and climate prediction models. A critical component of this research has been the development of the longwave and shortwave broadband radiative transfer code for general circulation model (GCM) applications, RRTMG, which is based on the single-column reference code, RRTM, also developed at AER. RRTMG is a rigorously tested radiation model that retains a considerable level of accuracy relative to higher resolution models and measurements despite the performance enhancements that have made it possible to apply this radiation code successfully to global dynamical models. This model includes the radiative effects of all significant atmospheric gases, and it treats the absorption and scattering from liquid and ice clouds and aerosols. RRTMG also includes a statistical technique for representing small-scale cloud variability, such as cloud fraction and the vertical overlap of clouds, which has been shown to improve cloud radiative forcing in global models. This development approach has provided a direct link from observations to the enhanced radiative transfer provided by RRTMG for application to GCMs. Recent comparison of existing climate model radiation codes with high resolution models has documented the improved radiative forcing capability provided by RRTMG, especially at the surface, relative to other GCM radiation models. Due to its high accuracy, its connection to observations, and its computational efficiency, RRTMG has been implemented operationally in many national and international dynamical models to provide validated radiative transfer for improving weather forecasts and enhancing the prediction of global climate change.

  10. Intercomparison of three South China Sea circulation models

    Institute of Scientific and Technical Information of China (English)

    DU Yan; WANG Dongxiao; ZHOU Weidong; WANG Weiqiang; LIU Xiongbin

    2004-01-01

    Three numerical oceanic circulation models: POM(Princeton ocean model), MICOM(Miami isopycnal coordinates ocean model) and GFDL model, which adopt sigma coordinate, isopycnal coordinate and depth coordinate respectively,are used in the South China Sea(SCS) circulation modeling. Model domain has the same topography, grid resolution,initial conditions and surface boundary conditions. The maximum ocean depth is set as 1000 m. Grid resolution is 0.5°×0.5°.Initial conditions are supplied by climatological temperature and salinity data in January. Climatological wind stress, surface temperature and salinity are used as surface forcing. Lateral boundaries take enclosed boundary conditions artificially. Focusing on the common point of different ocean circulation models, the circulation pattern in winter and summer, sea surface height in the northern SCS, seasonal cycle of the mixed layer thickness in the southem SCS,barotropic stream function in winter are selected to carry out intercomparison. In winter, a strong cyclonic gyre occupies the whole SCS. In summer, a strong anticyclonic gyre occupies the southern SCS and a weak cyclonic gyre occupies the northern SCS. The thickness of the mixed layer shows bimodal features in the southern SCS. Sea surface height anomaly(SSHA) in the northern SCS has an eastward propagating feature, in agreement with the remote sensing observation. Barotropic stream functions indicate that the circulation of the upper ocean is mainly forced by inputting of wind stress curl under closed boundary conditions. In addition, three models also show distinct differences. The basinscale circulation fiom MICOM is distinct. Output of POM has more mesoscale eddies than others. GFDL model seems good at simulating westward intensification.

  11. PWR hot leg natural circulation modeling with MELCOR code

    Energy Technology Data Exchange (ETDEWEB)

    Park, Jae Hong; Lee, Jong In [Korea Institute of Nuclear Safety, Taejon (Korea, Republic of)

    1997-12-31

    Previous MELCOR and SCDAP/RELAP5 nodalizations for simulating the counter-current, natural circulation behavior of vapor flow within the RCS hot legs and SG U-tubes when core damage progress can not be applied to the steady state and water-filled conditions during the initial period of accident progression because of the artificially high loss coefficients in the hot legs and SG U-tubes which were chosen from results of COMMIX calculation and the Westinghouse natural circulation experiments in a 1/7-scale facility for simulating steam natural circulation behavior in the vessel and circulation modeling which can be used both for the liquid flow condition at steady state and for the vapor flow condition at the later period of in-vessel core damage. For this, the drag forces resulting from the momentum exchange effects between the two vapor streams in the hot leg was modeled as a pressure drop by pump model. This hot leg natural circulation modeling of MELCOR was able to reproduce similar mass flow rates with those predicted by previous models. 6 refs., 2 figs. (Author)

  12. Genetic profiling of tumours using both circulating free DNA and circulating tumour cells isolated from the same preserved whole blood sample.

    Science.gov (United States)

    Rothwell, Dominic G; Smith, Nigel; Morris, Daniel; Leong, Hui Sun; Li, Yaoyong; Hollebecque, Antoine; Ayub, Mahmood; Carter, Louise; Antonello, Jenny; Franklin, Lynsey; Miller, Crispin; Blackhall, Fiona; Dive, Caroline; Brady, Ged

    2016-04-01

    Molecular information obtained from cancer patients' blood is an emerging and powerful research tool with immense potential as a companion diagnostic for patient stratification and monitoring. Blood, which can be sampled routinely, provides a means of inferring the current genetic status of patients' tumours via analysis of circulating tumour cells (CTCs) or circulating tumour DNA (ctDNA). However, accurate assessment of both CTCs and ctDNA requires all blood cells to be maintained intact until samples are processed. This dictates for ctDNA analysis EDTA blood samples must be processed with 4 h of draw, severely limiting the use of ctDNA in multi-site trials. Here we describe a blood collection protocol that is amenable for analysis of both CTCs and ctDNA up to four days after blood collection. We demonstrate that yields of circulating free DNA (cfDNA) obtained from whole blood CellSave samples are equivalent to those obtained from conventional EDTA plasma processed within 4 h of blood draw. Targeted and genome-wide NGS revealed comparable DNA quality and resultant sequence information from cfDNA within CellSave and EDTA samples. We also demonstrate that CTCs and ctDNA can be isolated from the same patient blood sample, and give the same patterns of CNA enabling direct analysis of the genetic status of patients' tumours. In summary, our results demonstrate the utility of a simple approach that enabling robust molecular analysis of CTCs and cfDNA for genotype-directed therapies in multi-site clinical trials and represent a significant methodological improvement for clinical benefit.

  13. [Analysis and comparison of theories of circulation of blood and qi in both eastern and western ancient medicines].

    Science.gov (United States)

    Wang, Tai

    2014-09-01

    In ancient Egypt, the theory of circulation of blood and qi was preliminarily established on the basis of cadaver dissection, gradually revised and improved following the progress of anatomy and physiology. However, the "Meridian Theory" of circulation of blood and qi in Chinese medicine had never been established on the basis of anatomical and physiological studies. Thus a suspicion was aroused, "whether the meridians really exist, or artificially assumed by imagination"? Therefore, in recent one half of a century, numerous scholars at home and abroad spent countless financial capacities and human power to study the essence of Meridians in order to find their material or substantial evidence, but with no breakthrough obtained. Nevertheless, in the 70th of the last century, studies on mechanisms of acupuncture analgesia and acupuncture anesthesia won an undoubtedly good result. Hence, the therapeutic effect of acupuncture on pain control was admitted by the "Consensus Statement on Acupuncture" at an international meeting held by NIH in Dec. 1997. Then the old Chinese acupuncture won an international acceptance and application. Therefore, the investigation of mechanism of acupuncture analgesia set up a positive model for future scientific researches on acupuncture mechanisms and essence of Meridians, as well as on other Chinese medical theories.

  14. The effects of long-term microgravity on autonomic regulation of blood circulation in crewmembers of the international space station

    Directory of Open Access Journals (Sweden)

    Roman М. Baevsky

    2014-11-01

    Full Text Available The article presents the results of space experiment “Pneumocard”. The investigation involved all 25 Russian members of the ISS crew. The total of 226 sessions were made including 130 aboard the ISS, 50 prior to launch and 46 on return from mission. The objective was to study effects of the spaceflight factors on autonomic regulation of blood circulation, respiration and cardiac contractility during long-duration mission. The purpose was to secure new research data that would clarify our present view of adaptation mechanisms. Registered were the following signals: electrocardiogram, impedance cardiogram, seismic cardiogram, pneumotachogram, finger photoplethysmogram. A set of hard- and software was used. Autonomic regulation of blood circulation by HRV analysis was investigated. It was shown that at the onset of a space mission parasympathetic involvement in regulation increases typically with subsequent mobilization of additional functional reserve. It guided the development of a functional states mathematical model incorporating the established types of autonomic regulation. Our data evidence that the combination of HRV analysis, pre-nosology diagnosis and probabilistic estimate of the pathology risk can reinforce the medical care program in space missions.

  15. TCM Treatment of Rheumatoid Arthritis by Supplementing the Kidney and Invigorating the Blood Circulation

    Institute of Scientific and Technical Information of China (English)

    吉海旺; 姚淑莲; 罗强; 曹小菊

    2002-01-01

    The therapeutic effects in treating the intermediate and late rheumatoid arthritis by supplementing the kidney and invigorating blood circulation were observed. In the 43 cases of the treatment group, No. 2 Qu Feng Shi Ling capsules (祛风湿灵胶囊2号) and Fenbid (芬必得) were prescribed, while in the 39 cases of the control group Lei Gong Teng Tablets (雷公藤总甙片) and Fenbid were given. The results showed that the total effective rate in the treatment group was more satisfactory than that in the control (P<0.05 or P<0.01). With less toxic effects, the former could better improve the local swelling and lower the blood viscosity.

  16. Arterial blood-pressure change and endogenous circulating substance P in man

    DEFF Research Database (Denmark)

    Henriksen, Jens Henrik Sahl; Kastrup, J; Schaffalitzky De Muckadell, O B

    1985-01-01

    Substance P (SP) is a powerful vasodilator and this peptide is today considered to be a chemical messenger. The potential effects on circulating SP of acute changes in arterial blood-pressure was investigated in nine subjects. An increase in arterial mean blood-pressure (+33%, P less than 0.001, n...... = 9) was obtained by infusion of angiotensin II and a decrease in pressure (-10%, P less than 0.005, n = 6) was obtained by ganglionic blockade. The concentration of SP in plasma, from supine subjects in the normotensive condition, ranged from 3 to 13 pmol/l (with a mean of 5.6 pmol/l). SP was thus...

  17. Precision of a new bedside method for estimation of the circulating blood volume

    DEFF Research Database (Denmark)

    Christensen, P; Eriksen, B; Henneberg, S W

    1993-01-01

    The present study is a theoretical and experimental evaluation of a modification of the carbon monoxide method for estimation of the circulating blood volume (CBV) with respect to the precision of the method. The CBV was determined from measurements of the CO-saturation of hemoglobin before...... and after ventilation with a gas mixture containing 20-50 ml of CO for a period of 10-15 min. A special Water's to and fro system was designed in order to avoid any leakage when measuring during intermittent positive pressure ventilation (IPPV). Blood samples were taken before and immediately after......, determination of CBV can be performed with an amount of CO that gives rise to a harmless increase in the carboxyhemoglobin concentration.(ABSTRACT TRUNCATED AT 250 WORDS)...

  18. Changes of blood circulation of the extremity after external fixation for tibia shaft defect: an experimental study

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Objective: To assess and compare two approaches, end to endcompression with lengthening (EECL) and segmental bone transport by lengthening (STBL), for long tubular bone defect and nonunion.Methods: Ten goats were used to establish the bone defect model of the mid-tibia. The bone defect ends were shortened step by step with a sulcated half-ring external fixator. Changes of the blood flow of the distal extremity were measured with pulse-Doppler monitor and angiography.Results: The blood flow in the distal extremity was not affected when bone defect was less than 15% of the original length. Blood circulatory disorder would appear in the distal extremity when bone defect ranged 15%-20% of the original length. The necrosis would appear in the extremity because of the blood circulatory obstacle when bone defect was more than 20% of the original length.Conclusions: EECL is an appropriate alternative of treatments if bone defect is less than 15%; while SBTL may be feasible if bone defect is over 20% of the original length. When bone defect ranges between 15% and 20%, EECL should be applied with great care on condition of keeping watch on the extremity circulation with pulse-Doppler monitor.

  19. Effects of repeated concentric and eccentric contractions on tendon blood circulation.

    Science.gov (United States)

    Kubo, K

    2015-06-01

    Previous studies demonstrated that treatment involving eccentric training was effective in the conservative management of chronic tendinosis. However, the mechanisms for these phenomena are unknown. The purpose of this study was to compare changes in blood circulation of the tendons after the repeated concentric and eccentric contractions. 11 healthy males volunteered for this study. Subjects performed the repeated concentric (CON) and eccentric (ECC) contractions (5 sets of 10 maximal voluntary contractions) of the plantar flexors. During and after repeated contractions, oxyhemoglobin (Oxy), deoxyhemoglobin (Deoxy), total hemoglobin (THb), and oxygen saturation (StO2) of the Achilles tendons were measured using red laser lights. Oxy and THb increased during and after ECC, but not CON. Deoxy decreased during both CON and ECC. Increase in StO2 during and after ECC was greater than that during and after CON. These results suggested that changes in blood circulation of the Achilles tendon during and after repeated eccentric contractions were more remarkable than those during and after repeated concentric contractions.

  20. Aptamers Selected to Postoperative Lung Adenocarcinoma Detect Circulating Tumor Cells in Human Blood

    Science.gov (United States)

    Zamay, Galina S; Kolovskaya, Olga S; Zamay, Tatiana N; Glazyrin, Yury E; Krat, Alexey V; Zubkova, Olga; Spivak, Ekaterina; Wehbe, Mohammed; Gargaun, Ana; Muharemagic, Darija; Komarova, Mariia; Grigorieva, Valentina; Savchenko, Andrey; Modestov, Andrey A; Berezovski, Maxim V; Zamay, Anna S

    2015-01-01

    Circulating tumor cells (CTCs) are rare cells and valuable clinical markers of prognosis of metastasis formation and prediction of patient survival. Most CTC analyses are based on the antibody-based detection of a few epithelial markers; therefore miss an important portion of mesenchymal cancer cells circulating in blood. In this work, we selected and identified DNA aptamers as specific affinity probes that bind to lung adenocarcinoma cells derived from postoperative tissues. The unique feature of our selection strategy is that aptamers are produced for lung cancer cell biomarkers in their native state and conformation without previous knowledge of the biomarkers. The aptamers did not bind to normal lung cells and lymphocytes, and had very low affinity to A549 lung adenocarcinoma culture. We applied these aptamers to detect CTCs, apoptotic bodies, and microemboli in clinical samples of peripheral blood of lung cancer and metastatic lung cancer patients. We identified aptamer-associated protein biomarkers for lung cancer such as vimentin, annexin A2, annexin A5, histone 2B, neutrophil defensin, and clusterin. Tumor-specific aptamers can be produced for individual patients and synthesized many times during anticancer therapy, thereby opening up the possibility of personalized diagnostics. PMID:26061649

  1. Histone Methylation Marks on Circulating Nucleosomes as Novel Blood-Based Biomarker in Colorectal Cancer

    Directory of Open Access Journals (Sweden)

    Ugur Gezer

    2015-12-01

    Full Text Available Circulating nucleic acids (CNAs are under investigation as a liquid biopsy in cancer as potential non-invasive biomarkers, as stable structure in circulation nucleosomes could be valuable sources for detection of cancer-specific alterations in histone modifications. Our interest is in histone methylation marks with a focus on colorectal cancer, one of the leading cancers respective the incidence and mortality. Our previous work included the analysis of trimethylations of lysine 9 on histone 3 (H3K9me3 and of lysine 20 on histone 4 (H4K20me3 by chromatin immuno- precipitation-related PCR in circulating nucleosomes. Here we asked whether global immunologic measurement of histone marks in circulation could be a suitable approach to show their potential as biomarkers. In addition to H3K9me3 and H4K20me3 we also measured H3K27me3 in plasma samples from CRC patients (n = 63 and cancer free individuals (n = 40 by ELISA-based methylation assays. Our results show that of three marks, the amounts of H3K27me3 (p = 0.04 and H4K20me3 (p < 0.001 were significantly lower in CRC patients than in healthy controls. For H3K9me3 similar amounts were measured in both groups. Areas under the curve (AUC in receiver operating characteristic (ROC curves indicating the power of CRC detection were 0.620 for H3K27me3, 0.715 for H4K20me3 and 0.769 for the combination of both markers. In conclusion, findings of this preliminary study reveal the potential of blood-based detection of CRC by quantification of histone methylation marks and the additive effect of the marker combination.

  2. Blood pressure and blood flow variation during postural change from sitting to standing: model development and validation

    DEFF Research Database (Denmark)

    Olufsen, M.S.; Ottesen, Johnny T.; Tran, H.T.

    2005-01-01

    Short-term cardiovascular responses to postural change from sitting to standing involve complex interactions between the autonomic nervous system, which regulates blood pressure, and cerebral autoregulation, which maintains cerebral perfusion. We present a mathematical model that can predict...... dynamic changes in beat-to-beat arterial blood pressure and middle cerebral artery blood flow velocity during postural change from sitting to standing. Our cardiovascular model utilizes 11 compartments to describe blood pressure, blood flow, compliance, and resistance in the heart and systemic circulation....... To include dynamics due to the pulsatile nature of blood pressure and blood flow, resistances in the large systemic arteries are modeled using nonlinear functions of pressure. A physiologically based submodel is used to describe effects of gravity on venous blood pooling during postural change. Two types...

  3. Modeling of Sulfur Retention in Circulating Fluidized Bed Coal Combustors

    Institute of Scientific and Technical Information of China (English)

    乔锐; 吕俊复; 刘青; 吴学安; 岳光溪

    2001-01-01

    A comprehensive model for predicting the sulfur retention performance in circulating fluidized bedcombustors was developed which involves the different residence times, the wide particle size distribution andthe different forms of sulfur in the coal. In addition, the reductive decomposition of CaSO4 is highlighted. Thesimulation results from the model show that the sulfur contents, the bed temperature, the sorbent particle sizedistribution and the sorbent activity or the maximum conversion rate can significantly influence the sulfuretention performance in circulating fluidized bed (CFB) combustors.``

  4. Stratospheric General Circulation with Chemistry Model (SGCCM)

    Science.gov (United States)

    Rood, Richard B.; Douglass, Anne R.; Geller, Marvin A.; Kaye, Jack A.; Nielsen, J. Eric; Rosenfield, Joan E.; Stolarski, Richard S.

    1990-01-01

    In the past two years constituent transport and chemistry experiments have been performed using both simple single constituent models and more complex reservoir species models. Winds for these experiments have been taken from the data assimilation effort, Stratospheric Data Analysis System (STRATAN).

  5. Oxygen supply to the fetal cerebral circulation in hypoplastic left heart syndrome: a simulation study based on the theoretical models of fetal circulation.

    Science.gov (United States)

    Sakazaki, Sayaka; Masutani, Satoshi; Sugimoto, Masaya; Tamura, Masanori; Kuwata, Seiko; Kurishima, Clara; Saiki, Hirofumi; Iwamoto, Yoichi; Ishido, Hirotaka; Senzaki, Hideaki

    2015-03-01

    Hypoxia due to congenital heart diseases (CHDs) adversely affects brain development during the fetal period. Head circumference at birth is closely associated with neuropsychiatric development, and it is considerably smaller in newborns with hypoplastic left heart syndrome (HLHS) than in normal newborns. We performed simulation studies on newborns with CHD to evaluate the cerebral circulation during the fetal period. The oxygen saturation of cerebral blood flow in newborns with CHD was simulated according to a model for normal fetal circulation in late pregnancy. We compared the oxygen saturation of cerebral blood flow between newborns with tricuspid atresia (TA; a disease showing univentricular circulation and hypoplasia of the right ventricle), those with transposition of the great arteries (TGA; a disease showing abnormal mixing of arterial and venous blood), and those with HLHS. The oxygen saturation of cerebral blood flow in newborns with normal circulation was 75.7 %, whereas it was low (49.5 %) in both newborns with HLHS and those with TA. Although the oxygen level is affected by the blood flow through the foramen ovale, the oxygen saturation in newborns with TGA was even lower (43.2 %). These data, together with previous reports, suggest that the cerebral blood flow rate is decreased in newborns with HLHS, and the main cause was strongly suspected to be retrograde cerebral perfusion through a patent ductus arteriosus. This study provides important information about the neurodevelopmental prognosis of newborns with HLHS and suggests the need to identify strategies to resolve this unfavorable cerebral circulatory state in utero.

  6. Comparison of Modified Chandler, Roller Pump, and Ball Valve Circulation Models for In Vitro Testing in High Blood Flow Conditions: Application in Thrombogenicity Testing of Different Materials for Vascular Applications

    Directory of Open Access Journals (Sweden)

    Wim van Oeveren

    2012-01-01

    We concluded that the Hemobile minimally affects blood and could be adjusted to high blood flows, simulating arterial shear stress. The Hemobile was used to measure hemocompatibility of graft material and showed Dyneema Purity UHMWPE fiber in many ways more hemocompatible than ePTFE and PET.

  7. MODELING NONLINEAR DYNAMICS OF CIRCULATING FLUIDIZED BEDS USING NEURAL NETWORKS

    Institute of Scientific and Technical Information of China (English)

    Wei; Chen; Atsushi; Tsutsumi; Haiyan; Lin; Kentaro; Otawara

    2005-01-01

    In the present work, artificial neural networks (ANNs) were proposed to model nonlinear dynamic behaviors of local voidage fluctuations induced by highly turbulent interactions between the gas and solid phases in circulating fluidized beds. The fluctuations of local voidage were measured by using an optical transmittance probe at various axial and radial positions in a circulating fluidized bed with a riser of 0.10 m in inner diameter and 10 m in height. The ANNs trained with experimental time series were applied to make short-term and long-term predictions of dynamic characteristics in the circulating fluidized bed. An early stop approach was adopted to enhance the long-term prediction capability of ANNs. The performance of the trained ANN was evaluated in terms of time-averaged characteristics, power spectra, cycle number and short-term predictability analysis of time series measured and predicted by the model.

  8. Advances of Studies on Mechanisms of Drugs for Activating Blood Circulation and Removing Blood Stasis in Treatment of Primary Liver Cancer

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    @@ Primary liver cancer is mainly characterized by the mass in hypochondriac region, stabbing pain at a fixative region, tenderness, dim complexion,vascular spider, vein exposure, livid tongue,ecchymosis, taut and uneven pulse and other symptoms of blood stasis. Experimental studies have found that the patient with liver cancer is often accompanied with disturbance of microcirculation,increase of blood viscosity and high blood agglutinative state. Therefore, activating blood circulation to remove blood stasis is clinically an important therapy for primary liver cancer. A great number of studies on the mechanisms have been carried out in China and other countries. The follow is a review about the mechanisms.

  9. Modelling the shelf circulation off eastern Tasmania

    Science.gov (United States)

    Oliver, Eric C. J.; Herzfeld, Mike; Holbrook, Neil J.

    2016-11-01

    The marine waters across Tasmanian's eastern continental shelf are biologically productive and home to economically important fisheries and aquaculture industries. However, the marine climate there is poorly understood. We use a high-resolution (∼2 km in the horizontal), three-dimensional ocean model for eastern Tasmania (ETAS) to examine the simulated mean state and seasonal cycle of temperature, salinity and three-dimensional flow field, and the evaluation of daily model outputs against in situ and remote observations for the 1993-2014 period. We also use the model to examine the roles of river input and tidal forcing. The model is evaluated against remotely-sensed sea surface temperature and in-situ observations of sea level and subsurface temperature, salinity, and currents. The mean state demonstrates the influence of two well-known boundary currents (the East Australian Current, EAC, and the Zeehan Current, ZC) as well as the effects of local freshwater input from river runoff. The EAC is dominant in summer and the ZC in winter; the influence of the EAC also increases northwards and in the offshore direction. In addition, the model indicates the presence of a semi-permanent subsurface (50-100 m depth) northward flow trapped near the coast. Cool freshwater runoff from the Derwent and Huon Rivers directly impacts the temperature and salinity in their estuaries but has little influence further across the shelf. Tidal forcing impacts the mean state through tide-river interactions which flush Frederick Henry Bay and Norfolk Bay with freshwater. Tidal forcing also impacts the variability of temperature all along the coastline, most likely due to changes in the turbulent mixing near to the coast. The ETAS model output data are available as a high-resolution representation of the mean state, seasonal variations, and interannual variability of Tasmania's eastern continental shelf marine climate.

  10. Interactions Between the Thermohaline Circulation and Tropical Atlantic SST in a Coupled General Circulation Model

    Science.gov (United States)

    Miller, Ron; Jiang, Xing-Jian; Travis, Larry (Technical Monitor)

    2001-01-01

    Tropical Atlantic SST shows a (statistically well-defined) decadal time scale in a 104-year simulation of unforced variability by a coupled general circulation model (CGCM). The SST anomalies superficially resemble observed Tropical Atlantic variability (TAV), and are associated with changes in the atmospheric circulation. Brazilian rainfall is modulated with a decadal time scale, along with the strength of the Atlantic trade winds, which are associated with variations in evaporation and the net surface heat flux. However, in contrast to observed tropical Atlantic variability, the trade winds damp the associated anomalies in ocean temperature, indicating a negative feedback. Tropical SST anomalies in the CGCM, though opposed by the surface heat flux, are advected in from the Southern Hemisphere mid-latitudes. These variations modulate the strength of the thermohaline circulation (THC): warm, salty anomalies at the equator sink drawing cold, fresh mid-latitude water. Upon reaching the equator, the latter inhibit vertical overturning and advection from higher latitudes, which allows warm, salty anomalies to reform, returning the cycle to its original state. Thus, the cycle results from advection of density anomalies and the effect of these anomalies upon the rate of vertical overturning and surface advection. This decadal modulation of Tropical Atlantic SST and the thermohaline circulation is correlated with ocean heat transport to the Northern Hemisphere high latitudes and Norwegian Sea SST. Because of the central role of equatorial convection, we question whether this mechanism is present in the current climate, although we speculate that it may have operated in palaeo times, depending upon the stability of the tropical water column.

  11. Development of a hydraulic model of the human systemic circulation

    Science.gov (United States)

    Sharp, M. K.; Dharmalingham, R. K.

    1999-01-01

    Physical and numeric models of the human circulation are constructed for a number of objectives, including studies and training in physiologic control, interpretation of clinical observations, and testing of prosthetic cardiovascular devices. For many of these purposes it is important to quantitatively validate the dynamic response of the models in terms of the input impedance (Z = oscillatory pressure/oscillatory flow). To address this need, the authors developed an improved physical model. Using a computer study, the authors first identified the configuration of lumped parameter elements in a model of the systemic circulation; the result was a good match with human aortic input impedance with a minimum number of elements. Design, construction, and testing of a hydraulic model analogous to the computer model followed. Numeric results showed that a three element model with two resistors and one compliance produced reasonable matching without undue complication. The subsequent analogous hydraulic model included adjustable resistors incorporating a sliding plate to vary the flow area through a porous material and an adjustable compliance consisting of a variable-volume air chamber. The response of the hydraulic model compared favorably with other circulation models.

  12. THE THEORETICAL MODEL FOR PREDICTING CIRCULATION VELOCITY OF HYDRAULIC BRAKE

    Institute of Scientific and Technical Information of China (English)

    刘英林; 侯春生

    1997-01-01

    By rational hypothesis of fluid flow pattern, applied the law of conservation of energy and integrated the laboratory test results, finished the prediction by the theoretical model of circulation velocity of hydraulic brake which is important parameter. Thus provide the theoritical basis for hydraulic brake of belt conveyor whose research has just been started.

  13. Using the Gamma-Poisson Model to Predict Library Circulations.

    Science.gov (United States)

    Burrell, Quentin L.

    1990-01-01

    Argues that the gamma mixture of Poisson processes, for all its perceived defects, can be used to make predictions regarding future library book circulations of a quality adequate for general management requirements. The use of the model is extensively illustrated with data from two academic libraries. (Nine references) (CLB)

  14. A general circulation model (GCM) parameterization of Pinatubo aerosols

    Energy Technology Data Exchange (ETDEWEB)

    Lacis, A.A.; Carlson, B.E.; Mishchenko, M.I. [NASA Goddard Institute for Space Studies, New York, NY (United States)

    1996-04-01

    The June 1991 volcanic eruption of Mt. Pinatubo is the largest and best documented global climate forcing experiment in recorded history. The time development and geographical dispersion of the aerosol has been closely monitored and sampled. Based on preliminary estimates of the Pinatubo aerosol loading, general circulation model predictions of the impact on global climate have been made.

  15. A SYSTEM AND A DEVICE FOR ISOLATING CIRCULATING TUMOR CELLS FROM THE PERIPHERAL BLOOD IN VIVO

    Directory of Open Access Journals (Sweden)

    Michal Mego

    2015-08-01

    Full Text Available Circulating tumor cells (CTC play a crucial role in disseminating tumors and in the metastatic cascade. CTCs are found only in small numbers, and the limited amount of isolated CTCs makes it impossible to characterize them closely. This paper presents a proposal for a new system for isolating CTCs from the peripheral blood in vivo. The system enables CTCs to be isolated from the whole blood volume for further research and applications. The proposed system consists of magnetic nanoparticles covered by monoclonal antibodies against a common epithelial antigen, large supermagnets, which are used to control the position of the nanoparticles within the human body, and a special wire made of a magnetic core wrapped in a non-magnetic shell. The system could be used not only for isolating CTCs, but also for in vivo isolation of other rare cells from the peripheral blood, including hematopoietic and/or mesenchymal stem cells, with applications in regenerative medicine and/or in stem cell transplantation.

  16. Changes in EEG, systemic circulation and blood gas parameters following two or six aliquots of porcine surfactant.

    Science.gov (United States)

    Lundstrøm, K E; Greisen, G

    1996-06-01

    Surfactant instillation often causes transient EEG suppression, the cause remaining unknown. To compare the timing of the EEG changes with the timing of the changes in blood gases and systemic circulation we compared two administration modes: 20 preterm infants were randomly assigned to receive the initial dose of surfactant divided into two or six aliquots. Heart rate, blood pressure and transcutaneous blood gases were measured continuously, while left ventricular output was estimated intermittently. No difference in blood gas response was found between the groups, whereas the circulatory changes occurred more gradually with six aliquots. EEG suppression was similar in the two groups and not related to the circulatory or the respiratory changes. Left ventricular output increased in all patients following surfactant instillation. We conclude that the EEG suppression is not directly related to alterations in blood gases or systemic circulation.

  17. Winter Season Stratospheric Circulation in the SAMIL/LASG General Circulation Model

    Institute of Scientific and Technical Information of China (English)

    REN Rongcai; WU Guoxiong; Ming CAI; YU Jingjing

    2009-01-01

    In this paper, we examine the performance of the 26-level version of the SAMIL/LASG GCM (R42/L26)in simulating the seasonal cycle and perpetual winter mean stratospheric circulation as well as its variability by comparing them with the NCEP/NCAR reanalysis. The results show that the model is capable of reproducing many key features of the climatology and seasonal variation of the stratospheric circulation despite that the model's mean polar vortex is stronger and more zonally symmetric compared to the observation. Further diagnosis of the results from a perpetual-January-run of the SAMIL/LASG GCM indicates that the dominant winter-season oscillation mode in the model's stratosphere exhibits a similar inter-seasonal timescale with similar spatial patterns as those inferred from the NCEP/NCAR reanalysis. In particular, the simulated polar vortex oscillation mode exhibits a dominant inter-seasonal timescale of about 120 days, and is accompanied with the simultaneous poleward and downward propagation of temperature anomalies in the stratosphere and the equatorward propagation of temperature anomalies in the troposphere. More encouragingly, the 26-layer version of the SAMIL/LASG GCM is able to produce three strong Stratospheric Sudden Warming events during the 1825 days of perpetual-January integration, with the polar westerly jet completely reversed for a few weeks without imposing any prescribed anomalous forcing at the lower boundary.

  18. Effect of Chinese Herbs for Activating Blood Circulation,Removing Stasis and Supplementing Qi on the Circulating Endothelial Cells in Patients with Unstable Angina Pectoris

    Institute of Scientific and Technical Information of China (English)

    马丽红; 阮英茆; 焦增绵; 李晓惠

    2004-01-01

    Objective: To observe the effect and clinical significance of circulating endothelial cells (CEC) in the pathogenesis of coronary heart disease with unstable angina pectoris (CHD-UAP), and to explore the protective effect of Chinese herbs for activating blood circulation, removing stasis and supplementing Qi (CH) on CHD-UAP patient's CEC. Methods: Sixty patients with diagnosis of CHD-UAP confirmed and differentiated to be Qi-deficiency and blood stasis by TCM were randomly divided into two groups and treatime, with 1 month as one therapeutic course. The number of CEC in patients' blood circulation was counted before and after treatment. Besides, the number of CEC in 30 healthy persons was also counted for control.Results: The number of CEC in CHD-UAP patients was significantly higher than that in the healthy persons (P<0.01). After the patients were treated with CH, either TXL or HXTM, it significantly decreased (P<0.01)with insignificant difference between the two treated groups. Conclusion: CEC in CHD-UAP patients is severely damaged and endothelial function in disorder, Chinese herbs have protective effect on patients' CEC.

  19. [Magnetic field numerical calculation and analysis for magnetic coupling of centrifugal blood pump for extracorporeal circulation].

    Science.gov (United States)

    Hu, Zhaoyan; Lu, Lijun; Zhang, Tianyi; Chen, Zhenglong; Zhang, Tao

    2013-12-01

    This paper mainly studies the driving system of centrifugal blood pump for extracorporeal circulation, with the core being disc magnetic coupling. Structure parameters of disc magnetic coupling are related to the ability of transferring magnetic torque. Therefore, it is necessary to carry out disc magnetic coupling permanent magnet pole number (n), air gap length (L(g)), permanent magnet thickness (L(m)), permanent magnet body inside diameter (R(i)) and outside diameter (R(o)), etc. thoroughly. This paper adopts the three-dimensional static magnetic field edge element method of Ansys for numerical calculation, and analyses the relations of magnetic coupling each parameter to transmission magnetic torque. It provides a good theory basis and calculation method for further optimization of the disc magnetic coupling.

  20. Modelling Saturn's atmospheric circulations and cloud structure with OPUS

    Science.gov (United States)

    Zuchowski, L. C.; Read, P. L.; Yamazaki, Y. H.

    2009-04-01

    We are investigating Saturn's atmospheric circulations and cloud structure in the Northern and Southern hemisphere as initial value problems by use of the Oxford Planetary Unified model System (OPUS), a sophisticated GCM based on the UK Met Office Unified Model. Solving an extended form of the Hydrodynamic Primitive Equations, OPUS is capable of including 40 vertical levels from 0.1 bar to 100 bar. The model was initiated with temperature and balanced thermal wind profiles recently obtained by Cassini's Composite InfraRed Spectrometer (CIRS). A simple cloud scheme for the Jovian planets has been added to OPUS and is employed to model the three major cloud decks (ammonia, ammonium-hydrosulfide and water) on Saturn and the advection of these clouds with the atmosphere. We have already conducted several numerical studies with OPUS, simulating jet scale meridional circulations, the formation of cloud bands and discrete turbulent features on Jupiter. By modelling the dynamics and clouds of Saturn in a similar way, we are hoping to gain further insight into the formation of circulation cells over the zonal jet streams as well as to examine the distribution of atmospheric condensates in response to these motions. The model will also be used to numerically investigate the characteristic features in Saturn's Northern hemisphere. It is envisioned to directly compare the atmospheric configurations obtained for Saturn with previous results from the Jupiter model.

  1. Engineered stealth porous silicon nanoparticles via surface encapsulation of bovine serum albumin for prolonging blood circulation in vivo.

    Science.gov (United States)

    Xia, Bing; Zhang, Wenyi; Shi, Jisen; Xiao, Shou-jun

    2013-11-27

    Luminescent porous silicon nanoparticles (PSiNPs) have been widely used as drug delivery. However, fast biodegradation and short blood circulation have been major challenges for their biomedical applications. Herein, bovine serum albumin was readily encapsulated onto alkyl-terminated PSiNPs surfaces via hydrophobic interaction, which could significantly improve their water-dispersibility and long-term stability under physiological conditions. Furthermore, compared with PSiNPs alone, PSiNPs coated with bovine serum albumin remarkably reduced nonspecific cellular uptake in vitro and prolonged blood circulation in vivo.

  2. Impact of methods used to express levels of circulating fatty acids on the degree and direction of associations with blood lipids in humans.

    Science.gov (United States)

    Sergeant, Susan; Ruczinski, Ingo; Ivester, Priscilla; Lee, Tammy C; Morgan, Timothy M; Nicklas, Barbara J; Mathias, Rasika A; Chilton, Floyd H

    2016-01-28

    Numerous studies have examined relationships between disease biomarkers (such as blood lipids) and levels of circulating or cellular fatty acids. In such association studies, fatty acids have typically been expressed as the percentage of a particular fatty acid relative to the total fatty acids in a sample. Using two human cohorts, this study examined relationships between blood lipids (TAG, and LDL, HDL or total cholesterol) and circulating fatty acids expressed either as a percentage of total or as concentration in serum. The direction of the correlation between stearic acid, linoleic acid, dihomo-γ-linolenic acid, arachidonic acid and DHA and circulating TAG reversed when fatty acids were expressed as concentrations v. a percentage of total. Similar reversals were observed for these fatty acids when examining their associations with the ratio of total cholesterol:HDL-cholesterol. This reversal pattern was replicated in serum samples from both human cohorts. The correlations between blood lipids and fatty acids expressed as a percentage of total could be mathematically modelled from the concentration data. These data reveal that the different methods of expressing fatty acids lead to dissimilar correlations between blood lipids and certain fatty acids. This study raises important questions about how such reversals in association patterns impact the interpretation of numerous association studies evaluating fatty acids and their relationships with disease biomarkers or risk.

  3. Numerical experimentation of a diagnostic model of 3-D circulation in the Arabian Sea

    Digital Repository Service at National Institute of Oceanography (India)

    Shaji, C.; Bahulayan, N.; Dube, S.K.; Rao, A.D.

    Climatic circulation in the upper levels of the Arabian Sea and western equatorial Indian Ocean are computed using a 3-dimensional, 33 level diagnostic circulation model. A steady state solution is obtained within 30 days of model integration. Model...

  4. Abnormal arterial flows by a distributed model of the fetal circulation.

    Science.gov (United States)

    van den Wijngaard, Jeroen P H M; Westerhof, Berend E; Faber, Dirk J; Ramsay, Margaret M; Westerhof, Nico; van Gemert, Martin J C

    2006-11-01

    Modeling the propagation of blood pressure and flow along the fetoplacental arterial tree may improve interpretation of abnormal flow velocity waveforms in fetuses. The current models, however, either do not include a wide range of gestational ages or do not account for variation in anatomical, vascular, or rheological parameters. We developed a mathematical model of the pulsating fetoumbilical arterial circulation using Womersley's oscillatory flow theory and viscoelastic arterial wall properties. Arterial flow waves are calculated at different arterial locations from which the pulsatility index (PI) can be determined. We varied blood viscosity, placental and brain resistances, placental compliance, heart rate, stiffness of the arterial wall, and length of the umbilical arteries. The PI increases in the umbilical artery and decreases in the cerebral arteries, as a result of increasing placental resistance or decreasing brain resistance. Both changes in resistance decrease the flow through the placenta. An increased arterial stiffness increases the PIs in the entire fetoplacental circulation. Blood viscosity and peripheral bed compliance have limited influence on the flow profiles. Bradycardia and tachycardia increase and decrease the PI in all arteries, respectively. Umbilical arterial length has limited influence on the PI but affects the mean arterial pressure at the placental cord insertion. The model may improve the interpretation of arterial flow pulsations and thus may advance both the understanding of pathophysiological processes and clinical management.

  5. [Intracellular gold content of circulating blood cells using various gold compounds].

    Science.gov (United States)

    Herrlinger, J D; Beress, R; Hecker, U

    1984-01-01

    Evidence on the action mechanisms of gold salts in the treatment of rheumatoid arthritis is still inconclusive. The intracellular localization of the place of action is likely. Therefore not only the serum gold levels but also the intracellular concentration of gold are of special interest. We measured the gold concentration in the serum and in the blood cells after in vitro application of aurothiomalate (Tauredon), gold keratinate (Auro-Detoxin) and triethylphosphine-gold (Ridaura) and in blood samples of patients undergoing these gold salts treatments. Cell-bound concentrations were found to vary extensively as a function of the gold compound used. While no or very little gold was present intracellularly after administration of the 2 parenteral drugs, up to 40% of the circulating gold was found to bind to the cells after administration of the triethylphosphine compound for gastro-intestinal absorption. The red cell concentration was more or less the same as that in the extracellular compartment. Gold apparently accumulated in the white cells, because the cell-bound concentration relative to unit volume was up to 20 times higher than the plasma level. The method used did not offer any information on the actual binding site of gold in white cells, i.e. cytoplasm versus nucleus versus cell membrane.

  6. Administration of Traditional Chinese Blood Circulation Activating Drugs for Microvascular Complications in Patients with Type 2 Diabetes Mellitus

    Directory of Open Access Journals (Sweden)

    Lisha He

    2016-01-01

    Full Text Available Traditional Chinese medicine (TCM is an important complementary strategy for treating diabetes mellitus (DM in China. Traditional Chinese blood circulation activating drugs are intended to guide an overall approach to the prevention and treatment of microvascular complications of DM. The core mechanism is related to the protection of the vascular endothelium and the basement membrane. Here, we reviewed the scientific evidence underpinning the use of blood circulation activating drugs to prevent and treat DM-induced microvascular complications, including diabetic nephropathy (DN, diabetic peripheral neuropathy (DPN, and diabetic retinopathy (DR. Furthermore, we summarized the effects and mechanism of TCM on improving blood rheology, inhibiting aggregation of platelet, forming advanced glycation end products (AGEs, regulating oxidative stress, reducing blood fat, and improving lipid metabolism. The paper provides a new theoretical basis for the clinical practice of TCM in the prevention and treatment of DM and its microvascular complications.

  7. Effects of Chinese herbs capable of replenishing qi,nourishing yin and activating blood circulation and their compatibility on differentially expressed genes of ischemic myocardium

    Institute of Scientific and Technical Information of China (English)

    YIN HuiJun; GUO ChunYu; SHI DaZhuo

    2009-01-01

    This study was conducted to investigate the effects of Chinese herbs capable of replenishing qi,nourishing yin and activating blood circulation and their compatibility on differentially expressed genes of ischemic myocardium which were selected from differential expression profile we had established before,and to explore the underlying mechanism. The acute myocardial infarction (AMI) model was established by ligating the left anterior descending (LAD) coronary artery,then the model rats were randomly divided into the model group,the Metoprolol group,the replenishing qi nourishing yin (RN)group,the activating blood circulation (AB) group,and the replenishing qi,nourishing yin and activating blood circulation (RA) group. In addition,the normal group and the sham group were set up. The rats of medication groups were administered by intragastric gavage with corresponding drugs on the second day after operations,and the rats of the normal group and the sham group were given normal saline as the same time.Then the ischemic hearts were harvested on the 8th day after operation. The myocardial pathomorphological changes were observed under a light microscope. The mRNA changes of target genes such as COX5a and ATP5e were detected using Real-time fluorescence quantitative PCR (Q-PCR),and the activities of related enzymes were detected by colorimetric assay. The main results were as follows:the histological changes were observed by HE staining,and cardiocyte swelling,inflammatory cell infiltration and cytolysis were showed in regional ischemic myocardium of the model group,while the pathomorphological changes in all medication groups did not show obvious changes.Two genes related to energy metabolism,COX5a and ATP5e,were selected as the target genes which were down-regulated at the mRNA level in the medication groups. The activities of correlative functional enzymes also decreased in the RA group compared to that in the model group accordingly (P<0.05). The results indicated

  8. Clinical CVVH model removes endothelium-derived microparticles from circulation

    Directory of Open Access Journals (Sweden)

    Abdelhafeez H. Abdelhafeez

    2014-02-01

    Full Text Available Background: Endothelium-derived microparticles (EMPs are submicron vesicles released from the plasma membrane of endothelial cells in response to injury, apoptosis or activation. We have previously demonstrated EMP-induced acute lung injury (ALI in animal models and endothelial barrier dysfunction in vitro. Current treatment options for ALI are limited and consist of supportive therapies. We hypothesize that standard clinical continuous venovenous hemofiltration (CVVH reduces serum EMP levels and may be adapted as a potential therapeutic intervention. Materials and methods: EMPs were generated from plasminogen activation inhibitor-1 (PAI-1-stimulated human umbilical vein endothelial cells (HUVECs. Flow cytometric analysis was used to characterize EMPs as CD31- and annexin V-positive events in a submicron size gate. Enumeration was completed against a known concentration of latex beads. Ultimately, a concentration of ~650,000 EMP/mL perfusate fluid (total 470 mL was circulated through a standard CVVH filter (pore size 200 μm, flow rate 250 mL/hr for a period of 70 minutes. 0.5 mL aliquots were removed at 5- to 10-minute intervals for flow cytometric analysis. EMP concentration in the dialysate was measured at the end of 4 hours to better understand the fate of EMPs. Results: A progressive decrease in circulating EMP concentration was noted using standard CVVH at 250 mL/hr (a clinical standard rate from a 470 mL volume modelling a patient's circulation. A 50% reduction was noted within the first 30 minutes. EMPs entering the dialysate after 4 hours were 5.7% of the EMP original concentration. Conclusion: These data demonstrate that standard CVVH can remove EMPs from circulation in a circuit modelling a patient. An animal model of hemofiltration with induction of EMP release is required to test the therapeutic potential of this finding and potential of application in early treatment of ALI.

  9. Treatment of cloud radiative effects in general circulation models

    Energy Technology Data Exchange (ETDEWEB)

    Wang, W.C.; Dudek, M.P.; Liang, X.Z.; Ding, M. [State Univ. of New York, Albany, NY (United States)] [and others

    1996-04-01

    We participate in the Atmospheric Radiation Measurement (ARM) program with two objectives: (1) to improve the general circulation model (GCM) cloud/radiation treatment with a focus on cloud verticle overlapping and layer cloud optical properties, and (2) to study the effects of cloud/radiation-climate interaction on GCM climate simulations. This report summarizes the project progress since the Fourth ARM Science Team meeting February 28-March 4, 1994, in Charleston, South Carolina.

  10. Homing of circulating blood endothelial progenitor cells after myocardial infarction is mediated by Akt-SDF-1-signal pathway

    Institute of Scientific and Technical Information of China (English)

    赵岚

    2013-01-01

    Objective To investigate the expressions of protein kinase B(Akt) and stromal cell-derived factor-1(SDF-1) and their relations with circulating blood endothelial progenitor cell homing after myocardial infarction(MI). Methods MI was induced in the

  11. Gene expression analysis in pregnant women and their infants identifies unique fetal biomarkers that circulate in maternal blood

    Science.gov (United States)

    The discovery of fetal mRNA transcripts in the maternal circulation holds great promise for noninvasive prenatal diagnosis. To identify potential fetal biomarkers, we studied whole blood and plasma gene transcripts that were common to 9 term pregnant women and their newborns but absent or reduced in...

  12. Effects of Replenishing Qi, Promoting Blood Circulation and Resolving Phlegm on Vascular Endothelial Function and Blood Coagulation System in Senile Patients with Hyperlipemia

    Institute of Scientific and Technical Information of China (English)

    Yang Huimin; Han Libei; Sheng Tong; He Qiong; Liang Jinpu

    2006-01-01

    Objective: To observe the curative effect of the method of replenishing qi, promoting blood circulation and resolving phlegm on senile hyperlipemia and its effects on vascular endothelial function and blood coagulation system. Method: 96 patients with senile hyperlipemia were randomly divided into a treatment group and a of blood lipid, vascular endothelial function, blood coagulation system and safety. Results: After treatment,the treatment group was obviously superior to the control group (P<0.05) in reducing plasma total cholesterol (TC) and low density lipoprotein cholesterol (LDL-C) as well as in the ratio of thromboxane B2 (TXB2) to 6-keto-prostaglandin F1α (6-keto-PGF1α), D-dimer (D-D) and fibrinogen (FIB). Conclusion: Danshen Jueming Granules have the effect of regulating metabolism of blood lipid, and improving vascular endothelial function and blood coagulation system in senile patients with hyperlipemia.

  13. A seasonal model of the Mediterranean Sea general circulation

    Science.gov (United States)

    Roussenov, Vassil; Stanev, Emil; Artale, Vincenzo; Pinardi, Nadia

    1995-07-01

    This paper describes the seasonal characteristics of the Mediterranean Sea general circulation as simulated by a primitive equation general circulation model. The forcing is composed of climatological monthly mean atmospheric parameters, which are used to compute the heat and momentum budgets at the air-sea interface of the model. This allows heat fluxes to be determined by a realistic air-sea interaction physics. The Strait of Gibraltar is open, and the model resolution is ? in the horizontal and 19 levels in the vertical. The results show the large seasonal cycle of the circulation and its transient characteristics. The heat budget at the surface is characterized by lateral boundary intensifications occurring in downwelling and up welling areas of the basin. The general circulation is composed of subbasin gyres, and cyclonic motion dominates the northern and anticyclonic motion the southern part of the basin. The Atlantic stream which enters from Gibraltar and assumes the form of different boundary current subsystems is a coherent structure at the surface. At depth it appears as current segments and jets around a vigorous gyre system. The seasonal variability is manifested not only by a change in amplitude and location of the gyres but also by the appearance of seasonally recurrent gyres in different parts of the basin. Distinct westward propagation of these gyres occurs, together with amplitude changes. For the first time a Mersa-Matruh Gyre is successfully simulated due to the introduction of our heat fluxes at the air-sea interface. The seasonal thermocline is formed each summer, and a deep winter mixed layer is produced in the region of Levantine intermediate water formation. Deep water renewal does not occur, probably due to the climatological forcing used.

  14. Enhanced conjugation stability and blood circulation time of macromolecular gadolinium-DTPA contrast agent

    Energy Technology Data Exchange (ETDEWEB)

    Jenjob, Ratchapol [Department of New Drug Development, School of Medicine, Inha University, 2F A-dong, Jeongseok Bldg., Sinheung-dong 3-ga, Jung-gu, Incheon 400-712 (Korea, Republic of); Kun, Na [Department of Biotechnology, The Catholic University of Korea, 43 Jibong-ro, Wonmi-gu, Bucheon-si, Gyeonggi-do 420-743 (Korea, Republic of); Ghee, Jung Yeon [Utah-Inha DDS and Advanced Therapeutics, B-403 Meet-You-All Tower, SongdoTechnopark, 7–50, Songdo-dong, Yeonsu-gu, Incheon 406-840 (Korea, Republic of); Shen, Zheyu; Wu, Xiaoxia [Division of Functional Materials and Nano-Devices, Ningbo Institute of Materials Technology & Engineering (NIMTE), Chinese Academy of Sciences, 519 Zhuangshi Street, Zhenhai District, Ningbo, Zhejiang 315201 (China); Cho, Steve K., E-mail: scho@gist.ac.kr [Division of Liberal Arts and Science, GIST College, Gwangju Institute of Science and Technology, Gwangju 500-712 (Korea, Republic of); Lee, Don Haeng [Utah-Inha DDS and Advanced Therapeutics, B-403 Meet-You-All Tower, SongdoTechnopark, 7–50, Songdo-dong, Yeonsu-gu, Incheon 406-840 (Korea, Republic of); Department of Internal Medicine, School of Medicine, Inha University Hospital, Incheon 420-751 (Korea, Republic of); Yang, Su-Geun, E-mail: Sugeun.Yang@Inha.ac.kr [Department of New Drug Development, School of Medicine, Inha University, 2F A-dong, Jeongseok Bldg., Sinheung-dong 3-ga, Jung-gu, Incheon 400-712 (Korea, Republic of)

    2016-04-01

    In this study, we prepared macromolecular MR T1 contrast agent: pullulan-conjugated Gd diethylene triamine pentaacetate (Gd-DTPA-Pullulan) and estimated residual free Gd{sup 3+}, chelation stability in competition with metal ions, plasma and tissue pharmacokinetics, and abdominal MR contrast on rats. Residual free Gd{sup 3+} in Gd-DTPA-Pullulan was measured using colorimetric spectroscopy. The transmetalation of Gd{sup 3+} incubated with Ca{sup 2+} was performed by using a dialysis membrane (MWCO 100–500 Da) and investigated by ICP-OES. The plasma concentration profiles of Gd-DTPA-Pullulan were estimated after intravenous injection at a dose 0.1 mmol/kg of Gd. The coronal-plane abdominal images of normal rats were observed by MR imaging. The content of free Gd{sup 3+}, the toxic residual form, was less than 0.01%. Chelation stability of Gd-DTPA-Pullulan was estimated, and only 0.2% and 0.00045% of Gd{sup 3+} were released from Gd-DTPA-Pullulan after 2 h incubation with Ca{sup 2+} and Fe{sup 2+}, respectively. Gd-DTPA-Pullulan displayed the extended plasma half-life (t{sub 1/2,α} = 0.43 h, t{sub 1/2,β} = 2.32 h), much longer than 0.11 h and 0.79 h of Gd-EOB-DTPA. Abdominal MR imaging showed Gd-DTPA-Pullulan maintained initial MR contrast for 30 min. The extended plasma half-life of Gd-DTPA-Pullulan probably allows the prolonged MR acquisition time in clinic with enhanced MR contrast. - Highlights: • Macromolecule (pullulan) conjugated Gd contrast agent (Gd-DTPA-Pullulan) showed the extended plasma half-life (t{sub 1/2,α} = 0.43 h, t{sub 1/2,β} = 2.32 h) in comparison with Gd-EOB-DTPA • Gd-DTPA-pullulan T1 contrast agent exhibited strong chelation stability against Gd. • The extended blood circulation attributed the enhanced and prolonged MR contrast on abdominal region of rats. • The extended blood circulation may provide prolonged MR acquisition time window in clinics.

  15. Augmentation of blood circulation to the fingers by warming distant body areas

    Science.gov (United States)

    Koscheyev, V. S.; Leon, G. R.; Paul, S.; Tranchida, D.; Linder, I. V.

    2000-01-01

    Future activities in space will require greater periods of time in extreme environments in which the body periphery will be vulnerable to chilling. Maintaining the hands and fingers in comfortable conditions enhances finger flexibility and dexterity, and thus effects better work performance. We have evaluated the efficacy of promoting heat transfer and release by the extremities by increasing the blood flow to the periphery from more distant parts of the body. The experimental garment paradigm developed by the investigators was used to manipulate the temperature of different body areas. Six subjects, two females and four males, were evaluated in a stage-1 baseline condition, with the inlet temperature of the circulating water in the liquid cooling/warming garment (LCWG) at 33 degrees C. At stage 2 the total LCWG water inlet temperature was cooled to 8 degrees C, and at stage 3 the inlet water temperature in specific segments of the LCWG was warmed (according to protocol) to 45 degrees C, while the inlet temperature in the rest of the LCWG was maintained at 8 degrees C. The following four body-area-warming conditions were studied in separate sessions: (1) head, (2) upper torso/arm, (3) upper torso/arm/head, and (4) legs/feet. Skin temperature, heat flux and blood perfusion of the fingers, and subjective perception of thermal sensations and overall physical comfort were assessed. Finger temperature (T(fing)) analyses showed a statistically significant condition x stage interaction. Post-hoc comparisons (T(fing)) indicated that at stage 3, the upper torso/arm/head warming condition was significantly different from the head, upper torso/arm and legs/feet conditions, showing an increase in T(fing). There was a significant increase in blood perfusion in the fingers at stage 3 in all conditions. Subjective perception of hand warmth, and overall physical comfort level significantly increased in the stage 3 upper torso/arm/head condition. The findings indicate that

  16. Polyethylene glycol-modified arachidyl chitosan-based nanoparticles for prolonged blood circulation of doxorubicin.

    Science.gov (United States)

    Termsarasab, Ubonvan; Yoon, In-Soo; Park, Ju-Hwan; Moon, Hyun Tae; Cho, Hyun-Jong; Kim, Dae-Duk

    2014-04-10

    Doxorubicin (DOX)-loaded nanoparticles based on polyethylene glycol-conjugated chitosan oligosaccharide-arachidic acid (CSOAA-PEG) were explored for potential application to leukemia therapy. PEG was conjugated with CSOAA backbone via amide bond formation and the final product was verified by (1)H NMR analysis. Using the synthesized CSOAA-PEG, nanoparticles having characteristics of a 166-nm mean diameter, positive zeta potential, and spherical shape were produced for the delivery of DOX. The mean diameter of CSOAA-PEG nanoparticles in the serum solution (50% fetal bovine serum) remained relatively constant over 72 h as compared with CSOAA nanoparticles (changes of 20.92% and 223.16%, respectively). The sustained release pattern of DOX from CSOAA-PEG nanoparticles was displayed at physiological pH, and the release rate increased under the acidic pH conditions. The cytotoxicity of the CSOAA-PEG conjugate was negligible in human leukemia cells (K562) at the concentrations tested (∼ 100 μg/ml). The uptake rate of DOX from the nanoparticles by K562 cells was higher than that from the solution. Judging from the results of pharmacokinetic studies in rats, in vivo clearance rate of DOX from the CSOAA-PEG nanoparticle group was slower than other groups, subsequently extending the circulation period. The PEGylated CSOAA-based nanoparticles could represent an effective nano-sized delivery system for DOX which has been used for the treatment of blood malignancies.

  17. Immunomagnetic Nano-Screening Chip for Circulating Tumor Cells Detection in Blood

    Science.gov (United States)

    Horton, A. P.; Lane, N.; Tam, J.; Sokolov, K.; Garner, H. R.; Uhr, J. W.; Zhang, X. J.

    2010-03-01

    We present a novel method towards diagnose cancer at an early stage via a blood test. Early diagnosis is high on the future agenda of oncologists because of significant evidence that it will result in a higher cure rate. Capture of circulating tumor cells (CTCs) which are known to escape from carcinomas at an early stage offers such an opportunity. We design, fabricate and optimize the nanomagnetic-screening chip that captures the CTCs in microfluid, and further integrate the nano-chip with the new multispectral imaging system so that it can quantify different tumor markers and automate the entire instrument. Specifically, hybrid plasmonic (Fe2O3-core Au shell) nanoparticles, conjugated a collection of antibodies especially chosen to target breast cancer CTCs, with high magnetic susceptibility will be used for effective immunomagnetic CTC isolation. Greatly increased sensitivity over previous attempts is demonstrated by decreasing the length scale for interactions between the magnetic-nanoparticle-tagged CTCs and the isolative magnetic field, while increasing the effective cross-sectional area over which this interaction takes place. The screening chip is integrated with a novel hyperspectral microscopic imaging (HMI) platform capable of recording the entire emission spectra in a single pass evaluation. The combined system will precisely quantify up to 10 tumor markers on CTCs.

  18. Genetic Variation in the Natriuretic Peptide System, Circulating Natriuretic Peptide Levels, and Blood Pressure

    DEFF Research Database (Denmark)

    Jeppesen, Jørgen L; Nielsen, Søren J; Torp-Pedersen, Christian;

    2012-01-01

    BackgroundIn a large collaborative study (n > 50,000), common variants in the natriuretic peptide (NP) genes were found to be associated with circulating NP levels and also with blood pressure (BP) levels based on office BP measurements (OBPMs). It is unknown if determining an individual's BP by ...... evidence that the NP system plays an important role in BP regulation.American Journal of Hypertension 2012; doi:10.1038/ajh.2012.96.......-h ambulatory BP measurements (ABPMs) will influence the effect of NP gene variations on BP levels.MethodsWe used rs632793 at the NPPB (NP precursor B) locus to investigate the relationship between genetically determined serum N-terminal pro-brain NP (NT-proBNP) concentrations and BP levels......). Office BP decreased across the genotypes from A:A to G:G, but the differences did not reach statistical significance (P = 0.12).ConclusionsThis study suggests that 24-h ABPMs is a better method than OBPMs to detect significant differences in BP levels related to genetic variance and provides further...

  19. Modeling the ocean circulation in the Bering Sea

    Institute of Scientific and Technical Information of China (English)

    HU Haoguo; WANG Jia

    2008-01-01

    With parameterized wave mixing, the circulation and the tidal current in the Bering Sea were simulated simultaneously using the three-dimensional Princeton Ocean Model. The simulated circulation pattern in the deep basin is relatively stable,cyclonic, and has little seasonal change. The Bering Slope Current between 200-1000m isobaths was estimated to be 5 Sv in volume transport. The Kamchatka Current was estimated to be 20 Sv off the Kamchatka Peninsula. The Bering shelf circulations vary with season, driven mainly by wind. These features are consistent with historical estimates. A counter current was captured flowing southeastward approximately along the 200 m isobath of the Bering Slope, opposite to the northwestward Bering Slope Current, which needs to be validated by observations. An upwelling current is located in the shelf break (120-1000 m) area, which may imply the vertical advection of nutrients for supporting the Bering Sea Green Belt seasonal plankton blooms in the breakslope area. The Bering Slope Current is located in a downwelling area.

  20. High Resolution Global Modeling of the Atmospheric Circulation

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    An informal review is presented of recent developments in numerical simulation of the global atmospheric circulation with very fine numerical resolution models. The focus is on results obtained recently with versions of the GFDL SKYHI model and the Atmospheric Model for the Earth Simulator (AFES) global atmospheric models. These models have been run with effective horizontal grid resolution of ~10-40 km and fine vertical resolution. The results presented demonstrate the utility of such models for the study of a diverse range of phenomena. Specifically the models are shown to simulate the development of tropical cyclones with peak winds and minimum central pressures comparable to those of the most intense hurricanes actually observed. More fundamentally, the spectrum of energy content in the mesoscale in the flow can be reproduced by these models down to near the smallest explicitly-resolved horizontal scales. In the middle atmosphere it is shown that increasing horizontal resolution can lead to significantly improved overall simulation of the global-scale circulation. The application of the models to two specific problems requiring very fine resolution global will be discussed. The spatial and temporal variability of the vertical eddy flux of zonal momentum associated with gravity waves near the tropopause is evaluated in the very fine resolution AFES model. This is a subject of great importance for understanding and modelling the flow in the middle atmosphere. Then the simulation of the small scale variations of the semidiurnal surface pressure oscillation is analyzed, and the signature of significant topographic modulation of the semidiurnal atmospheric tide is identified.

  1. Determination of vascular endothelial growth factor (VEGF) in circulating blood: significance of VEGF in various leucocytes and platelets

    DEFF Research Database (Denmark)

    Werther, K; Christensen, Ib Jarle; Nielsen, Hans Jørgen

    2002-01-01

    . In corresponding blood samples, automated complete blood count was performed, and the number of each cell type was correlated to VEGF concentrations in plasma, serum and lysed whole blood. Finally, the impact of increasing clotting time on the release of VEGF to serum was analysed. RESULTS: Isolated neutrophils......AIM: The sources of increased vascular endothelial growth factor (VEGF) concentrations in peripheral blood from cancer patients are not known in detail. The aim of the present study was to evaluate correlations between the VEGF content in isolated leucocyte subpopulations and VEGF concentrations...... in plasma, serum and lysed whole blood. METHODS: In 51 colorectal cancer (CRC) patients, circulating T-lymphocytes, B-lymphocytes, monocytes, and granulocytes were isolated by means of immunomagnetic separation. Subsequently, the isolated cells were lysed and VEGF contents in the lysates were determined...

  2. Three-dimensional numerical modeling of nearshore circulation

    Institute of Scientific and Technical Information of China (English)

    SUN Detong

    2008-01-01

    A three-dimensional nearshore circulation model was developed by coupling CH3D, a three-dimensional hydrodynamic model and REF/DIF, a nearsbore wave transformation model. The model solves the three-dimensional wave-averaged equations of motion. Wave-induced effects on circulation were introduced in the form of radiation stresses, wave-induced mass transport, wave-induced enhancement of bottom friction and wave-induced turbulent mixing. Effects of breaking waves were considered following Svendsen (1984a and 1984b) and Stive and Wind (1986). The model was successfully tested against the analytical solution of longshore currents by Longuet and Higgins (1970). The model successfully simulated the undertow as observed in a laboratory experiment by Stive and Wind (1982). In addition, the model was applied to a physical model by Mory and Hamm (1997) and successfully reproduced the eddy behind a detached breakwater as well as the longshore current on the open beach and the contiguous eddy in the open area of the wave tank. While the qualitative agreement between model results and experimental observations was very good, the quantitative agreement needs to be further improved. Albeit difficult to explain every discrepancy between the model re- suits and observations, in general, sources of errors are attributed to the lack of understanding and comprehensive description of following processes: (1) the horizontal and vertical distribution of radiation stress, especially for breaking waves; (2) the detailed structure of turbulence;(3)Wave-current interaction (not included at this moment) ; and (4)the wave- current boundary layer and the resulting bottom shear stress.

  3. Simulating the Upper Ocean Circulation on the Belize Shelf: An Application of a Triply Nested-Grid Ocean Circulation Model

    Institute of Scientific and Technical Information of China (English)

    SHENG Jinyu; TANG Liqun; WANG Liang

    2005-01-01

    We present a three-level nested-grid ocean circulation modeling system for the Belize shelf of the western Caribbean Sea. The nested-grid system has three subcomponents: a coarse-resolution outer model of the western Caribbean Sea; an intermediate-resolution middle model of the southern Meso-American Barrier Reef System; and a fine-resolution inner model of the Belize shelf. The two-way nesting technique based on the semi-prognostic method is used to exchange information between the three subcomponents. We discuss two applications of the nested-grid system in this study. In the first application we simulate the seasonal mean circulation in the region, with the nested system forced by monthly mean surface fluxes and boundary forcing. The model results reproduce the general circulation features on the western Caribbean Sea and meso-scale circulation features on the Belize shelf. In the second application, we simulate the storm-induced circulation during Hurricane Mitch in 1998, with the nested-grid system forced by the combination of monthly mean forcing and idealized wind stress associated with the storm. The model results demonstrate that the storm-induced currents transport a large amount of estuarinc waters from coastal regions of Honduras and Guatemala to offshore reef atolls.

  4. Combustion Model FOr Staged Circulating Fluidized Bed BOiler

    Institute of Scientific and Technical Information of China (English)

    FandJianhua; LuQinggang; 等

    1997-01-01

    A mathematical model for atmospheric staged circulating fluidized bed combustion,which takes fluid dynamics,combustion,heat transfer,pollutants formation and retention,into account was developed in the institute of Engineering Thermophysics(IET)recently.The model of gas solid flow at the bottom of the combustor was treated by the two-phase theory of fluidized bed and in the upper region as a core-annulus flow structure.The chemical species CO,CO2,H2,H2O,CH4,O2 and N2 were considered in the reaction process.The mathematical model consisted of sub-modeles of fluid namics,coal heterogeneous and gas homogeneous chemical reactions.heat transfer,particle fragmentation and attrition,mass and energy balance tec.The developed code was applied to simulate an operating staged circulating fluidized bed combustion boiler of early design and the results were in good agreement with the operating data.The main submodels and simulation results are given in this paoper.

  5. Numerical Models of Human Circulatory System under Altered Gravity: Brain Circulation

    Science.gov (United States)

    Kim, Chang Sung; Kiris, Cetin; Kwak, Dochan; David, Tim

    2003-01-01

    A computational fluid dynamics (CFD) approach is presented to model the blood flow through the human circulatory system under altered gravity conditions. Models required for CFD simulation relevant to major hemodynamic issues are introduced such as non-Newtonian flow models governed by red blood cells, a model for arterial wall motion due to fluid-wall interactions, a vascular bed model for outflow boundary conditions, and a model for auto-regulation mechanism. The three-dimensional unsteady incompressible Navier-Stokes equations coupled with these models are solved iteratively using the pseudocompressibility method and dual time stepping. Moving wall boundary conditions from the first-order fluid-wall interaction model are used to study the influence of arterial wall distensibility on flow patterns and wall shear stresses during the heart pulse. A vascular bed modeling utilizing the analogy with electric circuits is coupled with an auto-regulation algorithm for multiple outflow boundaries. For the treatment of complex geometry, a chimera overset grid technique is adopted to obtain connectivity between arterial branches. For code validation, computed results are compared with experimental data for steady and unsteady non-Newtonian flows. Good agreement is obtained for both cases. In sin-type Gravity Benchmark Problems, gravity source terms are added to the Navier-Stokes equations to study the effect of gravitational variation on the human circulatory system. This computational approach is then applied to localized blood flows through a realistic carotid bifurcation and two Circle of Willis models, one using an idealized geometry and the other model using an anatomical data set. A three- dimensional anatomical Circle of Willis configuration is reconstructed from human-specific magnetic resonance images using an image segmentation method. The blood flow through these Circle of Willis models is simulated to provide means for studying gravitational effects on the brain

  6. A Global Jet/Circulation Model for Young Stars

    CERN Document Server

    Lery, T; Fiege, J D; Ray, T P; Frank, A; Bacciotti, F

    2002-01-01

    Powerful, highly collimated jets, surrounded by bipolar molecular outflows, are commonly observed near Young Stellar Objects (YSOs). In the usual theoretical picture of star formation, a jet is ejected from a magnetized accretion disk, with a molecular outflow being driven either by the jet or by a wider wind coming from the disk. Here, we propose an alternative global model for the flows surrounding YSOs. In addition to a central accretion-ejection engine driving the jet, the molecular outflow is powered by the infalling matter and follows a circulation pattern around the central object without necessarily being entrained by a jet. It is shown that the model produces a heated pressure-driven outflow with magneto-centrifugal acceleration and collimation. We report solutions for the three different parts of this self-similar model, i.e. the jet, the infalling envelope and the circulating matter that eventually forms the molecular outflow. This new picture of the accretion/outflow phase provides a possible expl...

  7. Circulating angiogenic cells can be derived from cryopreserved peripheral blood mononuclear cells.

    Directory of Open Access Journals (Sweden)

    Tanja Sofrenovic

    Full Text Available BACKGROUND: Cell transplantation for regenerative medicine has become an appealing therapeutic method; however, stem and progenitor cells are not always freshly available. Cryopreservation offers a way to freeze cells as they are generated, for storage and transport until required for therapy. This study was performed to assess the feasibility of cryopreserving peripheral blood mononuclear cells (PBMCs for the subsequent in vitro generation of their derived therapeutic population, circulating angiogenic cells (CACs. METHODS: PBMCs were isolated from healthy human donors. Freshly isolated cells were either analyzed immediately or cryopreserved in media containing 6% plasma serum and 5% dimethyl sulfoxide. PBMCs were thawed after being frozen for 1 (early thaw or 28 (late thaw days and analyzed, or cultured for 4 days to generate CACs. Analysis of the cells consisted of flow cytometry for viability and phenotype, as well as functional assays for their adhesion and migration potential, cytokine secretion, and in vivo angiogenic potential. RESULTS: The viability of PBMCs and CACs as well as their adhesion and migration properties did not differ greatly after cryopreservation. Phenotypic changes did occur in PBMCs and to a lesser extent in CACs after freezing; however the potent CD34(+VEGFR2(+CD133(+ population remained unaffected. The derived CACs, while exhibiting changes in inflammatory cytokine secretion, showed no changes in the secretion of important regenerative and chemotactic cytokines, nor in their ability to restore perfusion in ischemic muscle. CONCLUSION: Overall, it appears that changes do occur in cryopreserved PBMCs and their generated CACs; however, the CD34(+VEGFR2(+CD133(+ progenitor population, the secretion of pro-vasculogenic factors, and the in vivo angiogenic potential of CACs remain unaffected by cryopreservation.

  8. The regulation of method of tonifying Qi and activating blood circulation in the related gene expressions after spinal cord injury

    Institute of Scientific and Technical Information of China (English)

    Xiao Fan; Li Zhang

    2016-01-01

    Spinal cord injury is a disease of high incidence and low cure rate without any ideal treatment. Among the complex pathological reactions, the post-injury abnormal expressions of many genes may be an important one. Method of tonifying Qi and activating blood circulation, which is one of the most important treatments of spinal cord injury in Traditional Chinese Medicine and has been used extensively in clinic, is proved to be effective in the treatment of spinal cord injury. Recently, many scholars have carried out a lot of studies in this filed and acquired notable achievements. The essay concludes mechanisms of the regulation of method of tonifying Qi and activating blood circulation in the related gene expressions after spinal cord injury to provide new thoughts and new methods for the treatment and study of spinal cord injury.

  9. Circulating MicroRNAs in maternal blood as potential biomarkers for fetal hypoxia in-utero.

    Directory of Open Access Journals (Sweden)

    Clare L Whitehead

    Full Text Available Stillbirth affects 1 in 200 pregnancies and commonly arises due to a lack of oxygen supply to the fetus. Current tests to detect fetal hypoxia in-utero lack the sensitivity to identify many babies at risk. Emerging evidence suggests that microRNAs derived from the placenta circulate in the maternal blood during pregnancy and may serve as non-invasive biomarkers for pregnancy complications. In this study, we examined the expression of miRs known to be regulated by hypoxia in two clinical settings of significant fetal hypoxia: 1 labour and 2 fetal growth restriction. Six miRs (miR 210, miR 21, miR 424, miR 199a, miR 20b, and miR 373 were differentially expressed in pregnancies complicated by fetal hypoxia. In healthy term pregnancies there was a 4.2 fold increase in miR 210 (p<0.01, 2.7 fold increase in miR 424 (p<0.05, 2.6 fold increase in miR 199a (p<0.01 and 2.3 fold increase in miR 20b (p<0.05 from prior to labour to delivery of the fetus. Furthermore, the combined expression of miR 21 and miR 20b correlated with the degree of fetal hypoxia at birth determined by umbilical cord lactate delivery (r = 0.79, p = 0.03. In pregnancies complicated by severe preterm fetal growth restriction there was upregulation of the hypoxia-regulated miRs compared to gestation-matched controls: 3.6 fold in miR 210 (p<0.01, 3.6 fold in miR 424 (p<0.05, 5.9 fold in miR 21 (p<0.01, 3.8 fold in miR 199a (p<0.01 and 3.7 fold in miR 20b (p<0.01. Interestingly, the expression of miR 373 in gestation matched controls was very low, but was very highly expressed in FGR (p<0.0001. Furthermore, the expression increased in keeping with the degree of in-utero hypoxia estimated by fetal Doppler velocimetry. We conclude quantifying hypoxia-regulated miRs in the maternal blood may identify pregnancies at risk of fetal hypoxia, enabling early intervention to improve perinatal outcomes.

  10. Clinical Observation on Influence of Chinese Medicines for Promoting Blood Circulation to Remove Blood Stasis on FIB and DD in Plasma of Patients with Cerebral Thrombosis

    Institute of Scientific and Technical Information of China (English)

    梁晖; 陈甦; 陈少芳

    2002-01-01

    Objective: to study the influence of Chinese medicines for promoting blood circulation to remove blood stasis on fibrinogen (FIB) and D-dimer (DD) in plasma of patients with cerebral thrombosis. Method: 73 inpatients with acute cerebral thrombosis were randomly divided into a control group of 34 cases and a treatment group of 39 cases. The content of FIB and DD in plasma was detected before treatment and on the 7th and 14th days after treatment. Result: FIB content in plasma after treatment was lower than that before treatment in the control group (P<0.01) and more remarkable in the treatment group (P<0.001). There was an obvious difference in DD content before and after treatment in both groups. DD content on the 7th and 14th days after treatment in the treatment group was obviously higher than that in the control group (P<0.01 and P<0.05 respectively). Conclusion: Chinese medicines for promoting blood circulation to remove blood stasis can reduce the FIB content in plasma of patients with cerebral thrombosis, raise the DD content in plasma, cause the peak of DD content appear earlier and obviously improve hypercoagulability of blood in patients with cerebral thrombosis.

  11. A Global Ocean Biogeochemistry General Circulation Model and its Simulations

    Institute of Scientific and Technical Information of China (English)

    XU Yongfu; LI Yangchun; CHU Min

    2013-01-01

    An ocean biogeochemistry model was developed and incorporated into a global ocean general circulation model (LICOM) to form an ocean biogeochemistry general circulation model (OBGCM).The model was used to study the natural carbon cycle and the uptake and storage of anthropogenic CO2 in the ocean.A global export production of 12.5 Pg C yr-1 was obtained.The model estimated that in the pre-industrial era the global equatorial region within ±15° of the equator released 0.97 Pg C yr-1 to the atmosphere,which was balanced by the gain of CO2 in other regions.The post-industrial air-sea CO2 flux indicated the oceanic uptake of CO2 emitted by human activities.An increase of 20-50 μmol kg-1 for surface dissolved inorganic carbon (DIC) concentrations in the 1990s relative to pre-industrial times was obtained in the simulation,which was consistent with data-based estimates.The model generated a total anthropogenic carbon inventory of 105 Pg C as of 1994,which was within the range of estimates by other researchers.Various transports of both natural and anthropogenic DIC as well as labile dissolved organic carbon (LDOC)were estimated from the simulation.It was realized that the Southern Ocean and the high-latitude region of the North Pacific are important export regions where accumulative air-sea CO2 fluxes are larger than the DIC inventory,whereas the subtropical regions are acceptance regions.The interhemispheric transport of total natural carbon (DIC+LDOC) was found to be northward (0.11 Pg C yr-1),which was just balanced by the gain of carbon from the atmosphere in the Southern Hemisphere.

  12. [The influence of cardiosurgical intervention type and conditions of artificial blood circulation of perioperative dynamics of cardiac biomarkers].

    Science.gov (United States)

    Dement'eva, I I; Morozov, Iu A; Charnaia, M A

    2013-01-01

    125 patients after cardiac surgery operated on with the use of artificial blood circulation (ABC) were followed-up. Blood levels of cardiac protein, binding aliphatic acids and troponin 1 and 3 days after the operation were registered. The study showed that aorta clamping more then 90 minutes and hypothermic perfusion regimen influence cardiomyocites negatively. The state of "surgical trauma" and reperfusional myocardium damage was approximately the same during aortic surgery, myocardium revascularization with the use of aortic clamping and cardioplegia, and correction of the acquired heart disease, according to the dynamics of the studied proteins in blood. The minimal blood level of cardiac protein, binding aliphatic acids after coronary by-pass surgery on the working heart witnesses about negative influence of crystalloid hypothermic cardioplegia on coronary microcirculation.

  13. Study on time-based variation of blood circulation index, pulse wave energy, and RAI of healthy adult men after different eating times

    OpenAIRE

    Gyeong-Cheol Kim; Ki-Young Ji; Yi-Soon Kim; Yi-Sub Kwak

    2013-01-01

    Background: The purpose of this study is to examine the effects of different eating times on blood circulation index, pulse wave energy (E), and radial augmentation index (RAI) of healthy adult men. Methods: Blood circulation index, E, and RAI were measured using a three-dimensional (3-D) pulse imaging system (3-D MAC) at before, right after, 30 minutes after, 1 hour after, and 2 hours after eating. Results: In the blood circulation index, heart rate (HR), estimated cardiac output (ECO)...

  14. The stability of a zonally averaged thermohaline circulation model

    CERN Document Server

    Schmidt, G A

    1995-01-01

    A combination of analytical and numerical techniques are used to efficiently determine the qualitative and quantitative behaviour of a one-basin zonally averaged thermohaline circulation ocean model. In contrast to earlier studies which use time stepping to find the steady solutions, the steady state equations are first solved directly to obtain the multiple equilibria under identical mixed boundary conditions. This approach is based on the differentiability of the governing equations and especially the convection scheme. A linear stability analysis is then performed, in which the normal modes and corresponding eigenvalues are found for the various equilibrium states. Resonant periodic solutions superimposed on these states are predicted for various types of forcing. The results are used to gain insight into the solutions obtained by Mysak, Stocker and Huang in a previous numerical study in which the eddy diffusivities were varied in a randomly forced one-basin zonally averaged model. Resonant stable oscillat...

  15. Optimisation of a parallel ocean general circulation model

    Directory of Open Access Journals (Sweden)

    M. I. Beare

    Full Text Available This paper presents the development of a general-purpose parallel ocean circulation model, for use on a wide range of computer platforms, from traditional scalar machines to workstation clusters and massively parallel processors. Parallelism is provided, as a modular option, via high-level message-passing routines, thus hiding the technical intricacies from the user. An initial implementation highlights that the parallel efficiency of the model is adversely affected by a number of factors, for which optimisations are discussed and implemented. The resulting ocean code is portable and, in particular, allows science to be achieved on local workstations that could otherwise only be undertaken on state-of-the-art supercomputers.

  16. 冠心巴布膏活血化瘀作用研究%Study of Promoting Blood Circulation for Removing Blood Stasis by Guanxin Cataplasm

    Institute of Scientific and Technical Information of China (English)

    王岚; 杜茂波; 刘淑芝; 梁日欣; 王彦礼; 杨伟鹏; 王怡薇; 殷小杰; 杨庆

    2012-01-01

    目的:探讨冠心巴布膏(冠心膏)的活血化瘀作用,为其临床应用提供实验依据.方法:采用大鼠sc肾上腺素加冰浴的血瘀证模型,观察冠心膏高、中、低3个剂量(含生药10.0,5.0,2.5 g·kg-1)外用涂抹给药5d对模型动物全血黏度、血浆黏度、纤维蛋白原含量、红细胞压积、血小板聚集的影响.采用iv脑垂体后叶素(0.5 U·kg-1)造成大鼠急性心肌缺血模型,观察冠心膏(剂量同前)外用涂抹给药7d对模型动物心律失常的发生时间、持续时间及室性心律失常发生率的影响.结果:冠心膏高剂量能降低血浆黏度[由(1.101±0.064) mPa·s降至(1.039±0.025) mPa·s]、血小板聚集率[由(54.92±6.53)%降至(49.05±4.15)%]、200 s-1切变率下的全血黏度[由(3.81±0.31) mPa·s降至(3.53±0.27) mPa·s],延迟心律失常的开始时间[由(20.90±7.74)s升至(36.08±16.91)s],并降低心律失常的发生率(由75%降至37.5%)及持续时间[由(1133.75±298.71)s降至(881.20±115.48)s].低剂量能降低10 s-1切变率下的全血黏度[由(7.14 ±0.88) mPa·s降至(6.38±0.69) mPa·s]以及200 s -1切变率下的全血黏度[由(3.81±0.31) mPa·s降至(3.48±0.15) mPa·s],中剂量可以降低心律失常发生率(由75%降至37.5%)和持续时间[由(1133.75±298.71)s降至(816.43±243.46)s],与模型组比较均具有显著性差异(P<0.05,P<0.01).结论:冠心巴布膏可以改善血瘀证大鼠的血液流变学指标,防止心律失常的发生,具有一定的活血化瘀作用.%Objective: To investigate the actions of promoting blood circulation for removing blood stasis by Guanxin Cataplasm and provide the experimental basis for clinical applications of the cataplasm. Method; The rat blood stasis syndrome model was induced by subcutaneous injection of adrenalin with ice-bath, the indexes of hemorheology including fibrinogen, whole blood viscosity, plasma viscosity, packed cell volume and platelet aggregation. The acute rat

  17. South Atlantic circulation in a world ocean model

    Directory of Open Access Journals (Sweden)

    Matthew H. England

    Full Text Available The circulation in the South Atlantic Ocean has been simulated within a global ocean general circulation model. Preliminary analysis of the modelled ocean circulation in the region indicates a rather close agreement of the simulated upper ocean flows with conventional notions of the large-scale geostrophic currents in the region. The modelled South Atlantic Ocean witnesses the return flow and export of North Atlantic Deep Water (NADW at its northern boundary, the inflow of a rather barotropic Antarctic Circumpolar Current (ACC through the Drake Passage, and the inflow of warm saline Agulhas water around the Cape of Good Hope. The Agulhas leakage amounts to 8.7 Sv, within recent estimates of the mass transport shed westward at the Agulhas retroflection. Topographic steering of the ACC dominates the structure of flow in the circumpolar ocean. The Benguela Current is seen to be fed by a mixture of saline Indian Ocean water (originating from the Agulhas Current and fresher Subantarctic surface water (originating in the ACC. The Benguela Current is seen to modify its flow and fate with depth; near the surface it flows north-westwards bifurcating most of its transport northward into the North Atlantic Ocean (for ultimate replacement of North Atlantic surface waters lost to the NADW conveyor. Deeper in the water column, more of the Benguela Current is destined to return with the Brazil Current, though northward flows are still generated where the Benguela Current extension encounters the coast of South America. At intermediate levels, these northward currents trace the flow of Antarctic Intermediate Water (AAIW equatorward, though even more AAIW is seen to recirculate poleward in the subtropical gyre. In spite of the model's rather coarse resolution, some subtle features of the Brazil-Malvinas Confluence are simulated rather well, including the latitude at which the two currents meet. Conceptual diagrams of the recirculation and interocean

  18. High-circulating leptin levels are associated with increased blood pressure in uncontrolled resistant hypertension.

    Science.gov (United States)

    de Haro Moraes, C; Figueiredo, V N; de Faria, A P C; Barbaro, N R; Sabbatini, A R; Quinaglia, T; Ferreira-Melo, S E; Martins, L C; Demacq, C; Júnior, H M

    2013-04-01

    Leptin and aldosterone have been associated with the pathophysiological mechanisms of hypertension. However, despite studies showing the association of leptin with intima-media thickness, arterial distensibility and sympathetic nerve activation, the relationship between leptin and blood pressure (BP) in resistant hypertension (RHTN) is unknown. We aimed to assess the correlation of plasma leptin and aldosterone levels with BP in uncontrolled controlled RHTN (UCRHTN) and CRHTN patients. Plasma leptin and aldosterone levels, office BP, ambulatory BP monitoring and heart rate were measured in 41 UCRHTN, 39 CRHTN and 31 well-controlled HTN patients. No differences were observed between the three groups regarding gender, body mass index and age. The UCRHTN group had increased leptin when compared with CRHTN and well-controlled HTN patients (38.2±21.4, 19.6±8.7 and 20.94±13.9 ng ml(-1), respectively; P<0.05). Aldosterone levels values were also statistically different when comparing RHTN, CRHTN and well-controlled HTN patients (9.6±3.8, 8.1±5.0 and 8.0±4.7 ng dl(-1), respectively; P<0.05). As expected, UCRHTN patients had higher heart rate values compared with CRHTN and well-controlled HTN patients (86.2±7.2, 83.5±6.7 and 83.4±8.5, respectively; P<0.05). Plasma leptin positively correlated with systolic (SBP) and diastolic BP (DBP), and aldosterone (r=0.43, 0.35 and 0.47, respectively; all P<0.05) in UCRHTN, but neither in the CRHTN nor in the HTN group. Simple linear regression showed that SBP, DBP and aldosterone may be predicted by leptin (r(2)=0.16, 0.15 and 0.19, respectively; all P<0.05) only in the UCRHTN subgroup. In conclusion, UCRHTN patients have higher circulating leptin levels associated with increased plasma aldosterone and BP levels when compared with CRHTN and HTN subjects.

  19. Modeling of sulfur oxide removal in circulating fluidized bed absorbers

    Energy Technology Data Exchange (ETDEWEB)

    Mao, D.; Edwards, J.R.; Kuznetsov, A.V. [North Carolina State Univ., Raleigh, NC (United States). Dept. of Mechanical and Aerospace Engineering; Srivastava, R. [U.S. Environmental Protection Agency, Research Triangle Park, NC (United States). Air Pollution Prevention and Control Division

    2002-07-01

    This paper presents a model to simulate a circulating fluidized bed absorber (CFBA) that combines flow, mixing, and reaction through residence time distribution (RTD). These parameters are often overlooked in existing simulation models. In addition, the paper presents a newly developed gas-solid reaction model for sulphur dioxide removal by limestone. For the reaction model that considers RTD inside the core and annulus regions of CFBA, the macrochemical reaction is simulated according to microchemical reaction dynamics. The proposed model can predict sulphur dioxide and limestone distributions inside the CFBA and calculate how much limestone is needed to remove an appropriate amount of sulphur dioxide. Sulphur dioxide concentration at the outlet of the CFBA decreases as the distance of the CFBA increases from the bottom of the core region. Limestone concentration varies only very slightly in the core region, suggesting that limestone in the CFBA is efficiently utilized to remove sulphur oxide. Sulphur dioxide partial pressure at the exit of the CFBA decreases as fresh limestone increases at the inlet to the CFBA. 16 refs., 8 figs.

  20. Wave intensity analysis of a computational model of the pulmonary circulation

    Science.gov (United States)

    Hill, Nicholas A.; Qureshi, Muhammad Umar

    2015-11-01

    A multiscale computational model has been developed to predict flow and pressure in the pulmonary circulation, in which the flow and pressure in the smaller blood vessels are described using linearised equations in pairs of asymmetric structured trees joined at the roots. The geometric and elastic properties of all the blood vessels are described by physiological parameters. Magnetic resonance imaging (MRI) is used to determine the geometry of the large pulmonary arteries and veins, and to measure the cardiac output from the right ventricle. The flow in the large blood vessels is solved using a Lax-Wendroff scheme, and the admittances of the structured trees provide the boundary conditions linking each large artery to its respective large vein. The results of simulating various pathological conditions are in agreement with clinical observations, showing that the model has potential for assisting with diagnosis and treatment of circulatory diseases within the lung. We use wave intensity analysis to study the propagation of forward and backward, compression and decompression waves in our model. The approximations for the pulse wave velocity used in experiments on wave intensity analysis are assessed, and reflected waves lower the peak pressure in the right ventricle.

  1. The circulation of Icelandic waters – a modelling study

    Directory of Open Access Journals (Sweden)

    K. Logemann

    2013-04-01

    Full Text Available The three-dimensional flow, temperature and salinity fields of the North Atlantic including the Arctic Ocean covering the time period 1992 to 2006 are simulated with the numerical ocean model CODE. The model reveals several new insights and previously unknown structures which help us to clarify open questions on the regional oceanography of Icelandic waters. These relate to the structure and geographical distribution of the coastal current, the primary forcing of the North Icelandic Irminger Current (NIIC, the path of the Atlantic Water south-east of Iceland and the structure of the North Icelandic Jet (NIJ. The model's adaptively refined computational mesh has a maximum resolution of 1 km horizontal and 2.5 m vertical in Icelandic waters. CTD profiles from this region and the river discharge of 46 Icelandic watersheds, computed by the hydrological model WaSiM, are assimilated into the simulation. The model realistically reproduces the established elements of the circulation around Iceland. However, analysis of the simulated mean flow field also provides further insights. It suggests a distinct freshwater-induced coastal current that only exists along the south-west and west coasts which is accompanied by a counter-directed undercurrent. The simulated transport of Atlantic Water over the Icelandic shelf takes place in a symmetrical system of two currents, with the established NIIC over the north-western and northern shelf, and a current over the southern and south-eastern shelf herein called the South Icelandic Current (SIC. Both currents are driven by topographically induced distortions of the Arctic Front's barotropic pressure field. The SIC is simulated to be an upstream precursor of the Faroe Current (FC. The recently discovered North Icelandic Jet (NIJ also features in the model predictions and is found to be forced by the baroclinic pressure field of the Arctic Front, to originate east of the Kolbeinsey Ridge and to have a volume transport

  2. Venusian Polar Vortex reproduced by a general circulation model

    Science.gov (United States)

    Ando, Hiroki; Sugimoto, Norihiko; Takagi, Masahiro

    2016-10-01

    Unlike the polar vortices observed in the Earth, Mars and Titan atmospheres, the observed Venus polar vortex is warmer than the mid-latitudes at cloud-top levels (~65 km). This warm polar vortex is zonally surrounded by a cold latitude band located at ~60 degree latitude, which is a unique feature called 'cold collar' in the Venus atmosphere [e.g. Taylor et al. 1980; Piccioni et al. 2007]. Although these structures have been observed in numerous previous observations, the formation mechanism is still unknown. In addition, an axi-asymmetric feature is always seen in the warm polar vortex. It changes temporally and sometimes shows a hot polar dipole or S-shaped structure as shown by a lot of infrared measurements [e.g. Garate-Lopez et al. 2013; 2015]. However, its vertical structure has not been investigated. To solve these problems, we performed a numerical simulation of the Venus atmospheric circulation using a general circulation model named AFES for Venus [Sugimoto et al. 2014] and reproduced these puzzling features.And then, the reproduced structures of the atmosphere and the axi-asymmetirc feature are compared with some previous observational results.In addition, the quasi-periodical zonal-mean zonal wind fluctuation is also seen in the Venus polar vortex reproduced in our model. This might be able to explain some observational results [e.g. Luz et al. 2007] and implies that the polar vacillation might also occur in the Venus atmosphere, which is silimar to the Earth's polar atmosphere. We will also show some initial results about this point in this presentation.

  3. Cord blood-circulating endothelial progenitors for treatment of vascular diseases.

    Science.gov (United States)

    Lavergne, M; Vanneaux, V; Delmau, C; Gluckman, E; Rodde-Astier, I; Larghero, J; Uzan, G

    2011-04-01

    Adult peripheral blood (PB) endothelial progenitor cells (EPC) are produced in the bone marrow and are able to integrate vascular structures in sites of neoangiogenesis. EPCs thus represent a potential therapeutic tool for ischaemic diseases. However, use of autologous EPCs in cell therapy is limited by their rarity in adult PB. Cord blood (CB) contains more EPCs than PB, and they are functional after expansion. They form primary colonies that give rise to secondary colonies, each yielding more than 10(7) cells after few passages. The number of endothelial cells obtained from one unit of CB is compatible with potential clinical application. EPC colonies can be securely produced, expanded and cryopreserved in close culture devices and endothelial cells produced in these conditions are functional as shown in different in vitro and in vivo assays. As CB EPC-derived endothelial cells would be allogeneic to patients, it would be of interest to prepare them from ready-existing CB banks. We show that not all frozen CB units from a CB bank are able to generate EPC colonies in culture, and when they do so, number of colonies is lower than that obtained with fresh CB units. However, endothelial cells derived from frozen CB have the same phenotypical and functional properties than those derived from fresh CB. This indicates that CB cryopreservation should be improved to preserve integrity of stem cells other than haematopoietic ones. Feasibility of using CB for clinical applications will be validated in porcine models of ischaemia.

  4. Measurement of anterior and posterior circulation flow contributions to cerebral blood flow. An ultrasound-derived volumetric flow analysis.

    Science.gov (United States)

    Boyajian, R A; Schwend, R B; Wolfe, M M; Bickerton, R E; Otis, S M

    1995-01-01

    Ultrasound-derived volumetric flow analysis may be useful in answering questions of basic physiological interest in the cerebrovascular circulation. Using this technique, the authors have sought to describe quantitatively the complete concurrent flow relations among all four arteries supplying the brain. The aim of this study of normal subjects was to determine the relative flow contributions of the anterior (internal carotid arteries) and posterior (vertebral arteries) cerebral circulation. Comparisons between the observed and theoretically expected anterior and posterior flow distribution would provide an opportunity to assess traditional rheological conceptions in vivo. Pulsed color Doppler ultrasonography was used to measure mean flow rates in the internal carotid and vertebral arteries in 21 normal adults. The anterior circulation (internal carotid arteries bilaterally) carried 82% of the brain's blood supply and comprised 67% of the total vascular cross-sectional area. These values demonstrate precise concordance between observations in vivo and the theoretically derived (Hagen-Poiseuille) expected flow distribution. These cerebrovascular findings support the traditional conception of macroscopic blood flow. Further studies using ultrasound-derived volumetric analysis of the brain's arterial flow relations may illuminate the vascular pathophysiology underlying aging, cerebral ischemia, and dementias.

  5. The Effects of Chinese Medicines on Micro-circulation of Nail Folds and Blood Flow Velocity of Limbs in the Patients with Arteriosclerotic Obliteration

    Institute of Scientific and Technical Information of China (English)

    葛辛; 葛芃; 彭玉清; 陈云翔

    2003-01-01

    The effects of Chinese medicines on micro-circulation and blood flow velocity in arteries of the lower limbs were observed in 33 patients with arteriosclerotic obliteration (ASO). The results showed that the integral values of micro-circulation after treatment were obviously higher than those before treatment (P<0.05 or P<0.01). Blood flow velocity in arteries of the lower limbs determined with the color Doppler ultrasound detecting method after treatment were also obviously higher than those before treatment (P<0.05 or P<0.01). In this series of 33 ASO patients, the markedly effective rate was 36.36%, and the total effective rate was 63.64%. The observation indicates that the recipe prescribed according to the principle of supplementing qi and activating blood circulation can effectively improve micro-circulation in ASO patients, and accelerate blood flow in arteries of the lower limbs.

  6. The circulation of Icelandic waters – a modelling study

    Directory of Open Access Journals (Sweden)

    K. Logemann

    2013-10-01

    Full Text Available The three-dimensional flow, temperature and salinity fields of the North Atlantic, including the Arctic Ocean, covering the time period 1992 to 2006 are simulated with the numerical ocean model CODE. The simulation reveals several new insights and previously unknown structures which help us to clarify open questions on the regional oceanography of Icelandic waters. These relate to the structure and geographical distribution of the coastal current, the primary forcing of the North Icelandic Irminger Current (NIIC and the path of the Atlantic Water south-east of Iceland. The model's adaptively refined computational mesh has a maximum resolution of 1 km horizontal and 2.5 m vertical in Icelandic waters. CTD profiles from this region and the river discharge of 46 Icelandic watersheds, computed by the hydrological model WaSiM, are assimilated into the simulation. The model realistically reproduces the established elements of the circulation around Iceland. However, analysis of the simulated mean flow field also provides further insights. It suggests a distinct freshwater-induced coastal current that only exists along the south-west and west coasts, which is accompanied by a counter-directed undercurrent. The simulated transport of Atlantic Water over the Icelandic shelf takes place in a symmetrical system of two currents, with the established NIIC over the north-western and northern shelf, and a hitherto unnamed current over the southern and south-eastern shelf, which is simulated to be an upstream precursor of the Faroe Current (FC. Both currents are driven by barotropic pressure gradients induced by a sea level slope across the Greenland–Scotland Ridge. The recently discovered North Icelandic Jet (NIJ also features in the model predictions and is found to be forced by the baroclinic pressure field of the Arctic Front, to originate east of the Kolbeinsey Ridge and to have a volume transport of around 1.5 Sv within northern Denmark Strait. The

  7. The thrombotic potential of circulating tumor microemboli: computational modeling of circulating tumor cell-induced coagulation

    OpenAIRE

    Phillips, Kevin G.; Lee, Angela M.; Tormoen, Garth W.; Rigg, Rachel A.; Kolatkar, Anand; Luttgen, Madelyn; Bethel, Kelly; Bazhenova, Lyudmila; Kuhn, Peter; Newton, Paul; McCarty, Owen J.T.

    2014-01-01

    Thrombotic events can herald the diagnosis of cancer, preceding any cancer-related clinical symptoms. Patients with cancer are at a 4- to 7-fold increased risk of suffering from venous thromboembolism (VTE), with ∼7,000 patients with lung cancer presenting from VTEs. However, the physical biology underlying cancer-associated VTE remains poorly understood. Several lines of evidence suggest that the shedding of tissue factor (TF)-positive circulating tumor cells (CTCs) and microparticles from p...

  8. Cancer diagnosis and prognosis decoded by blood-based circulating microRNA signatures

    Directory of Open Access Journals (Sweden)

    Dharanija eMadhavan

    2013-06-01

    Full Text Available In the recent years, circulating microRNAs (miRNAs have garnered a lot of attention and interest in the field of disease biomarkers. With characteristics such as high stability, low cost, possibility of repeated sampling and minimal invasiveness, circulating miRNAs are ideal for development into diagnostic tests. There have been many studies reported on the potential of circulating miRNAs as early detection, prognostic and predictive biomarkers in cancer. Here, we have reviewed the use of plasma and serum miRNAs as biomarkers for cancer focusing on epithelial carcinomas (prostate, breast, lung, colorectal and gastric cancer and haematological malignancies (leukaemia and lymphoma. We have also addressed the common challenges that need to be overcome to achieve a successful bench to bedside transition.

  9. Decimeter waves in complex treatment of patients with cerebral blood circulation insufficiency

    Energy Technology Data Exchange (ETDEWEB)

    Strelkova, N.I.

    Decimeter waves (DMW) were introduced into the therapeutic armamentarium relatively recently. The effect of DMW on the CNS was studied in the Division of Neurology at the Central Scientific Research Institute of Resort Science and Physiotherapy for a number of years on four groups of patients: (A) Parkinson's Disease Group, (B) patients with sequelae of open and closed craniocerebral injuries, (C) cerebral stroke patients basically of the ischemic type and (D) patients with transitory cerebral circulation disorders. The experience gained showed that the use of DMW improved cerebral circulation and aided in development of collateral circulation. It was found that in cases of tremor Parkinsonism and in epilepsy, DMW therapy should be applied to the collarbone area. Application of DMW in early stages of injury needs further study. Obviously, a single therapeutic intervention cannot provide complete recovery; a combined treatment must be applied, advisably under conditions of a resort spa. 11 references.

  10. Influence of Molecular Structure on O2-Binding Properties and Blood Circulation of Hemoglobin‒Albumin Clusters.

    Directory of Open Access Journals (Sweden)

    Kana Yamada

    Full Text Available A hemoglobin wrapped covalently by three human serum albumins, a Hb-HSA3 cluster, is an artificial O2-carrier with the potential to function as a red blood cell substitute. This paper describes the synthesis and O2-binding properties of new hemoglobin‒albumin clusters (i bearing four HSA units at the periphery (Hb-HSA4, large-size variant and (ii containing an intramolecularly crosslinked Hb in the center (XLHb-HSA3, high O2-affinity variant. Dynamic light scattering measurements revealed that the Hb-HSA4 diameter is greater than that of either Hb-HSA3 or XLHb-HSA3. The XLHb-HSA3 showed moderately high O2-affinity compared to the others because of the chemical linkage between the Cys-93(β residues in Hb. Furthermore, the blood circulation behavior of 125I-labeled clusters was investigated by assay of blood retention and tissue distribution after intravenous administration into anesthetized rats. The XLHb-HSA3 was metabolized faster than Hb-HSA3 and Hb-HSA4. Results suggest that the molecular structure of the protein cluster is a factor that can influence in vivo circulation behavior.

  11. From the discovery of the circulation of the blood to the first steps in hemorheology: part 2.

    Science.gov (United States)

    Martins e Silva, J

    2009-12-01

    In the second and last part of this article, the contributions of two more brilliant figures are described in two sections, A and B, respectively Marcello Malpighi and Antonie van Leeuwenhoek. Through the originality of their work, both confirmed the pioneer William Harvey's observations and went on to add important details. Malpighi applied the optical microscope, until then used almost exclusively as a mere curiosity, to the in vitro study of the body tissues of various species. Outstanding among these pioneering observations was the visualization, for the first time, of capillary structures and blood corpuscles, on the basis of which he defined the composition of blood and, also for the first time, the concept of its fluidity. Furthermore, Malpighi confirmed the structural and functional continuity of the systemic circulation, which Harvey had been unable to demonstrate. Although van Leeuwenhoek lacked an academic education, he was able to see, through lenses he built himself, the microscopic details of the organic and inorganic world around him. Among numerous detailed observations of all types of substances, particularly important were the insights that he obtained into the nature of blood and red blood cells, to which he attributed the color of arterial and venous blood. He calculated the size of erythrocytes with striking accuracy. He was able to distinguish arterial from venous blood, confirmed the heart's function as the force behind the propulsion of the blood through the arteries and of the rhythmic nature of the pulse, and elucidated the return of the blood to the heart by different vessels, the veins. He visualized the bifurcation of the arteries into increasingly narrow vessels until they gave way to capillary networks, which in turn became successively wider venous channels. Van Leeuwenhoek demonstrated the existence of arterial-venous anastomoses. He discovered erythrocyte sedimentation and deformability (their shape varying from the original

  12. Elimination of young erythrocytes from blood circulation and altered erythropoietic patterns during paraquat induced anemic phase in mice.

    Science.gov (United States)

    Bhardwaj, Nitin; Saxena, Rajiv K

    2014-01-01

    Paraquat a widely used herbicide causes a variety of toxic effects on humans and animals. The present study is focused on the interaction of paraquat with the mouse erythroid system. Administration of paraquat (10 mg/kg body weight i.p. on alternate days in C57Bl/6 mice) induced a significant fall in blood erythrocyte count on 7, 14, and 21 day time points but the erythrocyte count reverted back to normal by 28th day indicating the emergence of refractoriness to paraquat. A marked surge in the blood reticulocyte count was observed in paraquat treated mice that also subsided by 28th day. Young erythrocytes in circulation were randomly eliminated from blood circulation in paraquat treated mice and a significant elevation in the level of reactive oxygen species (ROS) was also observed maximally the erythrocytes of this age group. Cells representing various stages of erythroid differentiation in bone marrow and spleen were identified and enumerated flow cytometrically based on their expression of Ter119 and transferrin (CD71) receptor. Proliferative activity of erythroid cells, their relative proportion as well as their absolute numbers fell significantly in bone marrow of paraquat treated mice but all these parameters were significantly elevated in spleens of paraquat treated mice. These changes were essentially restricted to the cells belonging to the two earliest stages of erythroid differentiation. Taken together our results indicate that paraquat treatment causes a transient anemia in mice resulting from random elimination of young circulating erythrocytes as well as depressed erythropoietic activity in bone marrow. Spleen erythropoietic activity however was elevated in paraquat treated mice.

  13. Mathematical Modeling of the Vacuum Circulation Refining Processof Molten Steel

    Institute of Scientific and Technical Information of China (English)

    魏季和

    2003-01-01

    The available studies in the literature on mathematical modeling of the vacuum circulation (RH) refining process of molten steel have briefly been reviewed. The latest advances obtained by the author with his research group have been Summarized. On the basis of the mass and momentum balances in the system, a new mathematical model for decarburization and degassing during the RH and RH-KTB refining processes of molten steel was proposed and developed. The refining roles of the three reaction sites, i.e. the up-snorkel zone, the droplet group and steel bath in the vacuum vessel, were considered in the model. It was assumed that the mass transfer of reactive components in the molten steel is the rate control step of the refining reactions. And the friction losses and drags of flows in the snorkels and vacuum vessel were all counted. The model was applied to the refining of molten steel in a multifunction RH degasser of 90 t capacity. The decarburization and degassing processes in the degasser under the RH and RH-KTB operating condi-tions were modeled and analyzed using this model. Besides, proceeded from the two-resistance mass transfer theory and the mass bal-ance of sulphur in the system, a kinetic model for the desulphurization by powder injection and blowing in the RH refining of molten steel was developed. Modeling and predictions of the process of injecting and blowing the lime based powder flux under assumed oper-ating modes with the different initial contents of sulphur and amounts of powder injected and blown in a RH degasser of 300 t capacity were carried out using the model. It was demonstrated that for the RH and RH-KTB refining processes, and the desulphurization by powder injection and blowing in the RH refining, the results predicted by the models were all in good agreement respectively with data from industrial experiments and practice. These models may be expected to offer some useful information and a reliable basis for de-termining and optimizing

  14. System model of a natural circulation integral test facility

    Science.gov (United States)

    Galvin, Mark R.

    The Department of Nuclear Engineering and Radiation Health Physics (NE/RHP) at Oregon State University (OSU) has been developing an innovative modular reactor plant concept since being initiated with a Department of Energy (DoE) grant in 1999. This concept, the Multi-Application Small Light Water Reactor (MASLWR), is an integral pressurized water reactor (PWR) plant that utilizes natural circulation flow in the primary and employs advanced passive safety features. The OSU MASLWR test facility is an electrically heated integral effects facility, scaled from the MASLWR concept design, that has been previously used to assess the feasibility of the concept design safety approach. To assist in evaluating operational scenarios, a simulation tool that models the test facility and is based on both test facility experimental data and analytical methods has been developed. The tool models both the test facility electric core and a simulated nuclear core, allowing evaluation of a broad spectrum of operational scenarios to identify those scenarios that should be explored experimentally using the test facility or design-quality multi-physics tools. Using the simulation tool, the total cost of experimentation and analysis can be reduced by directing time and resources towards the operational scenarios of interest.

  15. Clinical Observation in 45 Cases of Hemorrhagic Apoplexy of the Acute Stage Treated by Promoting Blood Circulation and Removing Blood Stasis

    Institute of Scientific and Technical Information of China (English)

    孙国柱

    2003-01-01

    To explore the therapeutic effects of the method of promoting blood circulation and removing blood stasis on hemorrhagic apoplexy of acute stage, 45 cases were treated by the method and observed for their conscious state and motor function, which were compared with 40 cases treated with regular western drugs. The results showed that the effective rate in the treated group was 82.2% and that in control group 60% with a significant difference (P<0.05) between the two groups. In the treated group, the scores of the conscious state and the motor function after treatment were elevated dramatically (P<0.01), indicating a much better effect in the treated group than in the control group.

  16. Reduced blood pressure of CFTR-F508del carriers correlates with diminished arterial reactivity rather than circulating blood volume in mice.

    Directory of Open Access Journals (Sweden)

    Veronica A Peotta

    Full Text Available The F508del mutation of the cystic fibrosis transmembrane conductance regulator (CFTR is the most common cause of cystic fibrosis (CF. Both CF patients and F508del carriers have decreased blood pressure. While this has been attributed to salt depletion, recent studies have shown F508del expression interferes with smooth muscle cell calcium mobilization. We tested the hypothesis that carriers of the F508del mutation have lower adult blood pressures and reduced aortic contractility without a reduction in circulating blood volume. By radiotelemetry, F508del heterozygous mice had significantly lower arterial pressures than wild-type C57BL/6 controls, with the greatest effect seen at the time of dark-to-light cycle transition (mean difference of 10 mmHg. To replicate the vascular effects of sympathetic arousal, isoproterenol and epinephrine were co-infused, and F508del mice again had significantly reduced arterial pressures. Aortas isolated from F508del heterozygous mice had significantly decreased constriction to noradrenaline (0.9 ± 0.2 versus 2.9 ± 0.7 mN. Inhibition of wild-type CFTR or the inositol triphosphate receptor replicated the phenotype of F508del aortas. CFTR carrier status did not alter circulating blood volume. We conclude the CFTR-F508del mutation decreases aortic contractility and lowers arterial pressures. As a cAMP-activated chloride channel that facilitates calcium mobilization, we speculate wild-type CFTR co-activation during adrenergic receptor stimulation buffers the vasodilatory response to catecholamines, and loss of this compensatory vasoconstrictor tone may contribute to the lower arterial pressures seen in heterozygote carriers of a CFTR-F508del mutation.

  17. Integrative assessment of kick boxers’ brain blood circulation and bio-electrical activity in conditions of correction technologies’ application

    Directory of Open Access Journals (Sweden)

    Romanov Y.N.

    2016-06-01

    Full Text Available Purpose: to scientifically substantiate the role of para-vertebral impacts on blood circulation and bio-electrical activity of kick boxers’ cortex. Material: in the research participated kick boxers (main group, n=62 and university students (control group, n=25 of 18-23 years’ age. Assessment of para-vertebral impacts with device Armos and classic massage was fulfilled with the help of the following methodic: trans-cranial dopplerography of head main arteries and cortex EEG of the tested. Results: it was found that with the help of para-vertebral impacts by device Armos linear velocity of cerebral blood flow reduces to normal limits and in- and inter-hemispheres’ interaction strength increases. Conclusions: para-vertebral impacts by device Armos activate integrative processes and inter-hemispheres’ interactions of different cortex areas of kick boxers. It can witness about better formation of functional systems, ensuring sports efficiency.

  18. Circulating atrial natriuretic peptide (ANP) and central blood volume (CBV) in cirrhosis

    DEFF Research Database (Denmark)

    Schütten, H J; Henriksen, Jens Henrik Sahl; Bendtsen, F

    1986-01-01

    or diuretic treatment. Central blood volume (CBV, i.e. the blood volume in the heart cavities, lungs, and aorta), determined from the mean transit time of 125I-labelled of 125I-labelled albumin and cardiac output, was significantly reduced in cirrhotics compared to controls (1.45 +/- 0.12 vs. 1.83 +/- 0.10 l...

  19. The spatial arrangement of the human large intestinal wall blood circulation

    Science.gov (United States)

    Kachlik, David; Baca, Vaclav; Stingl, Josef

    2010-01-01

    The aim of the study was to describe and depict the spatial arrangement of the colon microcirculatory bed as a whole. Various parts of the large intestine and terminal ileum were harvested from either cadaver or section material or gained peroperatively. Samples were then injected with India ink or methylmetacrylate Mercox resin for microdissection and corrosion casting for scanning electron microscopy. The results showed that extramural vasa recta ramified to form the subserous plexus, some of them passing underneath the colon taeniae. Branches of both short and long vasa recta merged in the colon wall, pierced the muscular layer and spread out as the submucous plexus, which extended throughout the whole intestine without any interruption. The muscular layer received blood via both the centrifugal branches of the submucous plexus and the minor branches sent off by the subserous plexus. The mucosa was supplied by the mucous plexus, which sent capillaries into the walls of intestinal glands. The hexagonal arrangement of the intestinal glands reflected their vascular bed. All three presumptive critical points are only gross anatomical points of no physiological relevance in healthy individuals. Neither microscopic weak points nor regional differences were proven within the wall of the whole large intestine. The corrosion casts showed a huge density of capillaries under the mucosa of the large intestine. A regular hexagonal pattern of the vascular bed on the inner surface was revealed. No microvascular critical point proofs were confirmed and a correlation model to various pathological states was created. PMID:20447248

  20. The spatial arrangement of the human large intestinal wall blood circulation.

    Science.gov (United States)

    Kachlik, David; Baca, Vaclav; Stingl, Josef

    2010-03-01

    The aim of the study was to describe and depict the spatial arrangement of the colon microcirculatory bed as a whole. Various parts of the large intestine and terminal ileum were harvested from either cadaver or section material or gained peroperatively. Samples were then injected with India ink or methylmetacrylate Mercox resin for microdissection and corrosion casting for scanning electron microscopy. The results showed that extramural vasa recta ramified to form the subserous plexus, some of them passing underneath the colon taeniae. Branches of both short and long vasa recta merged in the colon wall, pierced the muscular layer and spread out as the submucous plexus, which extended throughout the whole intestine without any interruption. The muscular layer received blood via both the centrifugal branches of the submucous plexus and the minor branches sent off by the subserous plexus. The mucosa was supplied by the mucous plexus, which sent capillaries into the walls of intestinal glands. The hexagonal arrangement of the intestinal glands reflected their vascular bed. All three presumptive critical points are only gross anatomical points of no physiological relevance in healthy individuals. Neither microscopic weak points nor regional differences were proven within the wall of the whole large intestine. The corrosion casts showed a huge density of capillaries under the mucosa of the large intestine. A regular hexagonal pattern of the vascular bed on the inner surface was revealed. No microvascular critical point proofs were confirmed and a correlation model to various pathological states was created.

  1. Clinical Analysis of Postpartum Blood Circulation Failure%产后血循环衰竭的临床分析

    Institute of Scientific and Technical Information of China (English)

    李秀文

    2015-01-01

    ObjectiveTo study the causes and treatment methods of analysis of postpartum blood circulation failure.Methods To study and analyze according to the pregnant women in our hospital received 48 cases of postpartum blood circulation failure occurred in patients with symptoms, discussed the clinical etiology of their treatment, review.ResultsThe production probability circulation failure accounted for 1.01% of the total number of the study, all 48 patients, including 25% patients of the total labor for more than 16 hours, with the second stage of labor 10.4% extension, a huge 20.8% of cases of fetal maternal preeclampsia, 8.3% belong to the hypertension disease - pregnancy early, these patients after treatment, were successfully discharged.Conclusion Perinatal health care, postpartum visits, observation etc. to better prevention effect on postpartum blood circulation failure, clinical should pay attention to the use of these measures, to ensure the safety of delivery.%目的:研究分析产后血循环衰竭的产生原因和治疗方法。方法根据我院接收的分娩孕妇出现产后血循环衰竭症状的48例患者来进行研究分析,对他们的临床病因进行探讨,回顾治疗方法。结果此次发生产后血循环衰竭的几率占研究总数的1.01%,全部共48例患者,其中有25%的患者其总产程超过了16 h,10.4%的患者第二产程延长,有20.8%的胎儿巨大病例,8.3%的产妇属于妊娠期高血压疾病-子痫前期,这些患者在治疗后,均顺利的出院。结论围产期的保健、产后的巡视、病情观察等能够对产后血循环衰竭起到较好的预防作用,临床中应该注意这些措施的使用,确保产妇的安全分娩。

  2. Molecular biosensing mechanisms in the spleen for the removal of aged and damaged red cells from the blood circulation.

    Science.gov (United States)

    Sugawara, Yoshiaki; Hayashi, Yuko; Shigemasa, Yuki; Abe, Yoko; Ohgushi, Ikumi; Ueno, Eriko; Shimamoto, Fumio

    2010-01-01

    Heinz bodies are intraerythrocytic inclusions of hemichrome formed as a result of hemoglobin (Hb) oxidation. They typically develop in aged red cells. Based on the hypothesis that hemichrome formation is an innate characteristic of physiologically normal Hb molecules, we present an overview of our previous findings regarding the molecular instability of Hb and the formation of hemichrome, as well as recent findings on Heinz body formation within normal human erythrocytes. Human adult Hb (HbO(2) A) prepared from healthy donors showed a tendency to produce hemichrome, even at close to physiological temperature and pH. Recent studies found that the number of Heinz bodies formed in red cells increased with increasing temperature when freshly drawn venous blood from healthy donors was subjected to mild heating above 37 °C. These findings suggest that Hb molecules control the removal of non-functional erythrocytes from the circulation via hemichrome formation and subsequent Heinz body clustering. In this review, we discuss the molecular biosensing mechanisms in the spleen, where hemichrome formation and subsequent Heinz body clustering within erythrocytes play a key role in the removal of aged and damaged red cells from the blood circulation.

  3. Effect of exosome isolation methods on physicochemical properties of exosomes and clearance of exosomes from the blood circulation.

    Science.gov (United States)

    Yamashita, Takuma; Takahashi, Yuki; Nishikawa, Makiya; Takakura, Yoshinobu

    2016-01-01

    Exosomes, which are expected to be delivery systems for biomolecules such as nucleic acids, are collected by several methods. However, the effect of exosome isolation methods on the characteristics of exosomes as drug carriers, such as recovery efficiency after sterile filtration and pharmacokinetics, has not been investigated despite the importance of these characteristics for the development of exosome-based delivery systems. In the present study, exosomes collected from murine melanoma B16-BL6 cells by several methods were compared with respect to dispersibility, recovery rate after filtering, and clearance from the blood circulation in mice. The exosomes were collected by three ultracentrifugation-based methods: simple ultracentrifugation/pelleting (pelleting method), ultracentrifugation with an iodixanol cushion (cushion method), and ultracentrifugation on an iodixanol density gradient (gradient method). The isolation methods had little effect on the particle number of exosomes. In contrast, transmission electron microscopy observation and size distribution measurement using tunable resistive pulse sensing indicated that the exosomes of the gradient method were more dispersed than the others. The exosomes were labeled with Gaussia luciferase and intravenously injected into mice. Clearance of injected exosomes from the blood circulation did not significantly change with isolation methods. When the exosomes were filtered using a 0.2-μm filter, the recovery rate was 82% for the exosomes of the gradient method, whereas it was less than 50% for the others. These results indicate that the exosome isolation method markedly affects the dispersibility and filtration efficiency of the exosomes.

  4. Molecular Biosensing Mechanisms in the Spleen for the Removal of Aged and Damaged Red Cells from the Blood Circulation

    Directory of Open Access Journals (Sweden)

    Eriko Ueno

    2010-07-01

    Full Text Available Heinz bodies are intraerythrocytic inclusions of hemichrome formed as a result of hemoglobin (Hb oxidation. They typically develop in aged red cells. Based on the hypothesis that hemichrome formation is an innate characteristic of physiologically normal Hb molecules, we present an overview of our previous findings regarding the molecular instability of Hb and the formation of hemichrome, as well as recent findings on Heinz body formation within normal human erythrocytes. Human adult Hb (HbO2 A prepared from healthy donors showed a tendency to produce hemichrome, even at close to physiological temperature and pH. Recent studies found that the number of Heinz bodies formed in red cells increased with increasing temperature when freshly drawn venous blood from healthy donors was subjected to mild heating above 37 °C. These findings suggest that Hb molecules control the removal of non-functional erythrocytes from the circulation via hemichrome formation and subsequent Heinz body clustering. In this review, we discuss the molecular biosensing mechanisms in the spleen, where hemichrome formation and subsequent Heinz body clustering within erythrocytes play a key role in the removal of aged and damaged red cells from the blood circulation.

  5. [Peculiarities of application of a cell saver apparatus in neonathal cardiosurgery using artificial blood circulation].

    Science.gov (United States)

    Kuz'menko, S O; Chasovs'kyĭ, K S

    2015-01-01

    Elaborated and introduced into the practice method of the blood preservation, while correction of complex inborn heart failures (IHF) in a newborn babies, was proposed. It assumes application of system for intraoperative reinfusion of own erythrocytes with processing of residual perfusate and their reinfusion in a postperfusion period. Impact of the blood preservation on volume of a donor's blood components, hematological indices and methods of application of washed erythrocytes while correction of complex IHF in a newborn babies were presented. The method was applied in 47 newborn babies, to whom an arterial switch was performed for the main vessels transposition.

  6. Ventricular Fibrillation Waveform Changes during Controlled Coronary Perfusion Using Extracorporeal Circulation in a Swine Model

    Science.gov (United States)

    Kaufman, Christopher L.; Baetiong, Alvin; Radhakrishnan, Jeejabai

    2016-01-01

    Background Several characteristics of the ventricular fibrillation (VF) waveform have been found predictive of successful defibrillation and hypothesized to reflect the myocardial energy state. In an open-chest swine model of VF, we modeled “average CPR” using extracorporeal circulation (ECC) and assessed the time course of coronary blood flow, myocardial metabolism, and myocardial structure in relation to the amplitude spectral area (AMSA) of the VF waveform without artifacts related to chest compression. Methods VF was induced and left untreated for 8 minutes in 16 swine. ECC was then started adjusting its flow to maintain a coronary perfusion pressure of 10 mmHg for 10 minutes. AMSA was calculated in the frequency domain and analyzed continuously with a 2.1 s timeframe and a Tukey window that moved ahead every 0.5 s. Results AMSA progressively declined during untreated VF. With ECC, AMSA increased from 7.0 ± 1.9 mV·Hz (at minute 8) to 12.8 ± 3.3 mV·Hz (at minute 14) (p < 0.05) without subsequent increase and showing a modest correlation with coronary blood flow of borderline statistical significance (r = 0.489, p = 0.0547). Myocardial energy measurements showed marked reduction in phosphocreatine and moderate reduction in ATP with increases in ADP, AMP, and adenosine along with myocardial lactate, all indicative of ischemia. Yet, ischemia did not resolve during ECC despite a coronary blood flow of ~ 30% of baseline. Conclusion AMSA increased upon return of coronary blood flow during ECC. However, the maximal level was reached after ~ 6 minutes without further change. The significance of the findings for determining the optimal timing for delivering an electrical shock during resuscitation from VF remains to be further explored. PMID:27536996

  7. Effects of pulsed electromagnetic fields on peripheral blood circulation in people with diabetes: A randomized controlled trial.

    Science.gov (United States)

    Sun, Jiahui; Kwan, Rachel Lai-Chu; Zheng, Yongping; Cheing, Gladys Lai-Ying

    2016-07-01

    Cutaneous blood flow provides nourishment that plays an essential role in maintaining skin health. We examined the effects of pulsed electromagnetic fields (PEMFs) on cutaneous circulation of dorsal feet. Twenty-two patients with diabetes mellitus (DM) and 21 healthy control subjects were randomly allocated to receive either PEMFs or sham PEMFs (0.5 mT, 12 Hz, 30 min). Blood flow velocity and diameter of the small vein were examined by using ultrasound biomicroscopy; also, microcirculation at skin over the base of the 1st metatarsal bone (Flux1) and distal 1st phalange (Flux2) was measured by laser Doppler flowmetry before and after intervention. Results indicated that PEMFs produced significantly greater changes in blood flow velocity of the smallest observable vein than did sham PEMFs (both P < 0.05) in both types of subjects. However, no significant difference was found in changes of vein diameter, nor in Flux1 and Flux2, between PEMFs and sham PEMFs groups in subjects with or without DM. We hypothesized that PEMFs would increase blood flow velocity of the smallest observable vein in people with or without DM. Bioelectromagnetics. 37:290-297, 2016. © 2016 Wiley Periodicals, Inc.

  8. Hemodynamic changes in the hepatic circulation after the modulation of the splenic circulation in an in vivo human experimental model.

    Science.gov (United States)

    Akamatsu, Nobuhisa; Sugawara, Yasuhiko; Satou, Shouichi; Mitsui, Tetsuya; Ninomiya, Riki; Komagome, Masahiko; Ozawa, Fumiaki; Beck, Yoshifumi

    2014-01-01

    Recent advances in liver surgery have highlighted the effects of the splenic circulation on the hepatic circulation with respect to the hepatic arterial buffer response (HABR). The aim of the present study was to investigate the actual hemodynamic effects of splenic artery embolization/ligation and splenectomy on the hepatic circulation in patients who underwent pancreaticoduodenectomy through in vivo experimental models. In vivo models of splenic artery embolization/ligation (only splenic artery clamping) and splenectomy (simultaneous clamping of both the splenic artery and the splenic vein) were created in 40 patients who underwent pancreaticoduodenectomy for various reasons. The portal venous flow velocity, the portal venous flow volume, the hepatic arterial flow velocity, and the hepatic arterial resistance index were measured with color Doppler ultrasonography. Clamping of the splenic artery induced an immediate and significant increase (16%) in the hepatic artery velocity (P splenic artery, the hepatic artery velocity remained significantly increased at the level of the initial clamping, and the portal venous flow significantly decreased (16%, P splenic vein, which was performed after the clamping of the splenic artery, resulted in an immediate and significant decrease (30%) in the portal venous flow (P splenic vein, there was no change in the portal flow, which remained significantly lower (28%) than the flow in controls, whereas the hepatic arterial flow further significantly increased (31%, P splenic artery embolization/ligation and splenectomy are effective for increasing hepatic arterial flow and decreasing portal flow, with splenectomy providing a greater advantage. The HABR underlies these hemodynamic changes.

  9. Modeling Coastal Ocean Optical Properties for Coupled Circulation and Ecosystem Models

    Science.gov (United States)

    2016-06-07

    Modeling Coastal Ocean Optical Properties for Coupled Circulation and Ecosystem Models Curtis D. Mobley Sequoia Scientific , Inc. 2700 Richards...N00014D01610002 http://www.onr.navy.mil/sci_tech/32/322/ocean_optics_biology.asp LONG-TERM GOAL The overall goal of this work , now completed, was to...wrong by orders of magnitude in Case 2 or optically shallow waters. The objective of this work was develop a radiative transfer model that can be

  10. FLAIR vascular hyperintensities and dynamic 4D angiograms for the estimation of collateral blood flow in posterior circulation occlusion

    Energy Technology Data Exchange (ETDEWEB)

    Foerster, Alex; Wenz, Holger; Kerl, Hans Ulrich; Al-Zghloul, Mansour; Habich, Sonia; Groden, Christoph [University of Heidelberg, Department of Neuroradiology, Universitaetsmedizin Mannheim, Mannheim (Germany)

    2014-09-15

    The objectives of this paper are to assess collateral blood flow in posterior circulation occlusion by MRI-based approaches (fluid-attenuated inversion recovery (FLAIR) vascular hyperintensities (FVHs), collateralization on dynamic 4D angiograms) and investigate its relation to ischemic lesion size and growth. In 28 patients with posterior cerebral artery (PCA) and 10 patients with basilar artery (BA) occlusion, MRI findings were analyzed, with emphasis on distal FVH and collateralization on dynamic 4D angiograms. In PCA occlusion, distal FVH was observed in 18/29 (62.1 %), in BA occlusion, in 8/10 (80 %) cases. Collateralization on dynamic 4D angiograms was graded 1 in 8 (27.6 %) patients, 2 in 1 (3.4 %) patient, 3 in 12 (41.4 %) patients, and 4 in 8 (27.6 %) patients with PCA occlusion and 0 in 1 (10 %) patient, 2 in 3 (30 %) patients, 3 in 1 (10 %) patient, and 4 in 5 (50 %) patients with BA occlusion. FVH grade showed neither correlation with initial or follow-up diffusion-weighted image (DWI) lesion size nor DWI-perfusion-weighted imaging (PWI) mismatch ratio. Collateralization on dynamic 4D angiograms correlated inversely with initial DWI lesion size and moderately with the DWI-(PWI) mismatch ratio. The combination of distal FVH and collateralization grade on dynamic 4D angiograms correlated inversely with initial as well as follow-up DWI lesion size and highly with the DWI-PWI mismatch ratio. In posterior circulation occlusion, FVH is a frequent finding, but its prognostic value is limited. Dynamic 4D angiograms are advantageous to examine and graduate collateral blood flow. The combination of both parameters results in an improved characterization of collateral blood flow and might have prognostic relevance. (orig.)

  11. Ethanol Extract of Persimmon Tree Leaves Improves Blood Circulation and Lipid Metabolism in Rats Fed a High-Fat Diet

    Science.gov (United States)

    Ryu, Ri; Kim, Hye-Jin; Moon, Byeongseok; Jung, Un Ju; Lee, Mi-Kyung; Lee, Dong Gun; Ryoo, ZaeYoung; Park, Yong Bok

    2015-01-01

    Abstract The leaves of the persimmon tree (PL) are known to have beneficial effects on hyperglycemia, dyslipidemia, and nonalcoholic fatty liver disease. We recently demonstrated that PL had antithrombotic properties in vitro. However, little is known about the antiplatelet and anticoagulant properties of PL in vivo. Omega-3 fatty acid (n-3 FA)-containing fish oil has been widely prescribed to improve blood circulation. This study compared the effects of dietary supplementation with an ethanol extract of PL or n-3 FA on blood coagulation, platelet activation, and lipid levels in vivo. Sprague–Dawley rats were fed a high-fat diet with either PL ethanol extract (0.5% w/w) or n-3 FA (2.5% w/w) for 9 weeks. Coagulation was examined by monitoring the activated partial thromboplastin time (aPTT) and prothrombin time. We examined plasma thromboxane B2 (TXB2), serotonin, and soluble P-selectin (sP-selectin) levels. The aPTT was significantly prolonged in the PL and n-3 FA supplement groups. PL also attenuated the TXB2 level and lowered arterial serotonin transporter mRNA expression, although it did not alter plasma serotonin or sP-selectin levels. C-reactive protein and leptin levels were significantly reduced by PL and n-3 FA supplementation. In addition, PL decreased plasma total- and low-density lipoprotein-cholesterol levels, as did n-3 FA treatment. These results indicated that the PL ethanol extract may have the potential to improve circulation by inhibiting blood coagulation and platelet activation and by reducing plasma cholesterol levels. PMID:26061228

  12. Study on the change of HPV DNA virus content, circulating blood and tissue miR indexes of patients with cervical cancer

    Institute of Scientific and Technical Information of China (English)

    Ru-Qiong Luo; LiangTang; Ping Xie; Yan-Mei Hu

    2016-01-01

    Objective:To study and observe the change status of HPV DNA virus content, circulating blood and tissue miR indexes of patients with cervical cancer.Methods:A total of 72 patients with cervical cancer in our hospital from February 2014 to September 2015 were selected as the observation group, 72 healthy women at the same period were selected as the control group, then the HPV DNA virus content and constitution, circulating blood and tissue miR indexes of two groups were analyzed and compared, and the detection results of observation group with stageⅠ,Ⅱ,Ⅲ andⅣ of cervical cancer were compared.Results:The rates of HPV DNA virus content and>500 in the observation group were all higher than those of control group, the circulating blood and tissue miR-21 were all higher than those of control group, while the circulating blood and tissue miR-126, miR-143 and miR-145 were all lower than those of control group, and the detection results of observation group with stageⅠ,Ⅱ,Ⅲ andⅣ of cervical cancer all had obvious differences, the differences were all significant.Conclusion:The changes of the status of HPV DNA virus content, circulating blood and tissue miR indexes of patients with cervical cancer are great, and the influence of cervical cancer stage for the detection results are great, so it has active guiding significance for the diagnosis and treatment of disease.

  13. A multi-level adaptation model of circulation for the western Indian Ocean

    Digital Repository Service at National Institute of Oceanography (India)

    Shaji, C.; Bahulayan, N.; Dube, S.K.; Rao, A.D.

    A three-dimensional, fully non-linear semi-diagnostic (adaptation) model is described. This model is used to compute the climatological mean circulation and to understand the role of local, steady forcing of the wind and thermohaline forcing...

  14. Model study of the upper circulation in the Sulu Sea and its relation to the South China Sea circulation

    Institute of Scientific and Technical Information of China (English)

    CAI Shuqun; HE Yinghui; LONG Xiaomin; WANG Shengan

    2008-01-01

    According to the satellite remote sensing monthly mean sea surface temperature data from 1998 to 2002, it is shown that, the Sulu Sea is dominated by a cold eddy both in summer and winter. A coupled single-layer/two-layer model is employed here to study the summery and wintry characteristics and dynamic mechanism of the upper circulation in the Sulu Sea. According to the numerical experiments, it is found that, due to the local monsoon stress cud, the upper circulation in the Sulu Sea is dominated by a weak anticyclonic eddy in summer and a strong cyclonic eddy in winter. Once there is a large outflow via the Sibutu Passage flowing out of the Sulu Sea in summer, the upper circulation in the Sulu Sea may be dominated by a cyclonic eddy instead of the normal anti- cyclonic one. Moreover, in summer, the water exchange between the Sulu Sea and South China Sea via the Mindoro and Balabac Straits might have some effect on the separation position and strength of the northward western boundary current next to the Indo - China Peninsula in the southern South China Sea.

  15. Circulating miRNA-155 is realted to blood pressure monitoring parameters

    Institute of Scientific and Technical Information of China (English)

    WU Ying; HUANG Yu-qing; HUANG Cheng; LI Jie; CAI An-ping; YU Xue-ju; ZHOU Dan

    2016-01-01

    Background Studies have shown that miRNA-155 played an important role in the process of development of hypertension.However,there is no date about miRNA-155 and blood pressure monitoring parameters.Therefore,we examined whether in hypertensive patients the expression level of plasma miRNA-155 related to 24-h ambulatory blood pressure monitoring (ABPM) parameters.Methods A cohort of adult patients scheduled to receive physical examination,office and ambulatory blood pressure monitoring.Quantitative reverse transcriptase polymerase chain reaction (qRT-PCR) was used to evaluate the expression of selected miRNA-155.The miRNA-155 expression level correlation between blood pressure parameters was assessed using the Spearman correlation coefficient.Results Fifty four essential hypertension patients (25 men;mean age,53.28 ± 9.52 years) and thirty healthy volunteers (15 men;mean age,53.03 ± 5.87 years) were included.We observed higher expression level of miRNA-155 (32.31 ± 2.85 vs 27.21 ± 1.59,P < 0.001) in hypertensive patients compared to healthy control individuals.MiRNA-155 expression level showed significant positive correlation with 24 h Daytime SBP (r =0.681,P < 0.001),24 h Daytime DBP (r =0.473,P < 0.001),24 h Daytime PP (r =0.565,P < 0.001) and dipping (r =0.257,P =0.018),respectively.Conclusions Our study showed that miRNA-155 expression level was associated positively with daytime blood pressure monitoring parameters,as well as blood pressure variability,indicating a possible implication of miRNA-155 in the pathogenesis of hypertension.

  16. Numerical modelling of geothermal and reflux circulation in Enewetak Atoll: Implications for dolomitization

    Science.gov (United States)

    Jones, G.; Whitaker, F.; Smart, P.; Sanford, W.

    2000-01-01

    Two types of regional-scale seawater circulation have been proposed to explain the formation of Enewetak Atoll dolomites: geothermal and reflux circulation. We have used a finite element groundwater flow model to examine the pattern, magnitude and dynamic interaction of these two different circulation mechanisms in Enewetak Atoll. Geothermal circulation is concentrated around the atoll-margin whereas refluxing mesosaline brines flow from the atoll interior towards the margin to restrict and eventually shut off geothermal circulation. Refluxing brines of 36-80??? can account for the salinity signature recorded in dolomite fluid inclusions. Distributions of fluid flux and Mg mass-balance calculations suggest that both geothermal and reflux circulation mechanisms could account for the observed distribution of dolomite in Enewetak Atoll. Furthermore, the atoll interior may be extensively dolomitized as observed in other atolls. (C) 2000 Elsevier Science B.V. All rights reserved.Two types of regional-scale seawater circulation have been proposed to explain the formation of Enewetak Atoll dolomites: geothermal and reflux circulation. We have used a finite element groundwater flow model to examine the pattern, magnitude and dynamic interaction of these two different circulation mechanisms in Enewetak Atoll. Geothermal circulation is concentrated around the atoll-margin whereas refluxing mesosaline brines flow from the atoll interior towards the margin to restrict and eventually shut off geothermal circulation. Refluxing brines of 36-80 per mil can account for the salinity signature recorded in dolomite fluid inclusions. Distributions of fluid flux and Mg mass-balance calculations suggest that both geothermal and reflux circulation mechanisms could account for the observed distribution of dolomite in Enewetak Atoll. Furthermore, the atoll interior may be extensively dolomitized as observed in other atolls.

  17. Innovative Strategy in Treating Angina Pectoris with Chinese Patent Medicines by Promoting Blood Circulation and Removing Blood Stasis: Experience from Combination Therapy in Chinese Medicine.

    Science.gov (United States)

    Xiong, Xing-Jiang; Wang, Zhong; Wang, Jie

    2015-01-01

    Coronary heart disease (CHD) is one of the leading causes of death worldwide. Moreover, angina pectoris is one of the most important types of CHD. Therefore, prevention and effective treatment of angina pectoris is of utmost importance in both China and western countries. However, undesirable effects of antianginal therapy do influence treatment adherence to a certain extent. Therefore, it's not surprising that, complementary and alternative medicine (CAM), including Chinese medicine (CM), are widely welcomed among patients with CHD, hoping that it might complement western medicine. In our previous studies, blood stasis syndrome (BSS) (Xueyu Zheng) was the main syndrome (Zheng-hou) of angina pectoris. Currently, China Food and Drug Administration authoritatively recommended more than 200 Chinese patent medicines (CPMs) as complementary or adjunctive therapies for symptom management and enhancing quality of life along with mainstream care on angina pectoris management in mainland China. This paper reviewed 4 kinds of most frequently-used CPMs by promoting blood circulation and removing blood stasis in the treatment of angina pectoris. It aims to evaluate the current evidence of CPMs in combination therapy for angina pectoris. This review indicated that CPMs as adjunctive treatment to routine antianginal therapy play an active role in reducing the incidence of primary endpoint events, decreasing anginal attack rate, and improving electrocardiogram. Additionally, CPMs have been proven relatively safe. Further rigorously designed clinical trials should be conducted to confirm the results.

  18. Dried-blood spots: a cost-effective field method for the detection of Chikungunya virus circulation in remote areas.

    Directory of Open Access Journals (Sweden)

    Soa Fy Andriamandimby

    Full Text Available BACKGROUND: In 2005, there were outbreaks of febrile polyarthritis due to Chikungunya virus (CHIKV in the Comoros Islands. CHIKV then spread to other islands in the Indian Ocean: La Réunion, Mauritius, Seychelles and Madagascar. These outbreaks revealed the lack of surveillance and preparedness of Madagascar and other countries. Thus, it was decided in 2007 to establish a syndrome-based surveillance network to monitor dengue-like illness. OBJECTIVE: This study aims to evaluate the use of capillary blood samples blotted on filter papers for molecular diagnosis of CHIKV infection. Venous blood samples can be difficult to obtain and the shipment of serum in appropriate temperature conditions is too costly for most developing countries. METHODOLOGY AND PRINCIPAL FINDINGS: Venous blood and dried-blood blotted on filter paper (DBFP were collected during the last CHIKV outbreak in Madagascar (2010 and as part of our routine surveillance of dengue-like illness. All samples were tested by real-time RT-PCR and results with serum and DBFP samples were compared for each patient. The sensitivity and specificity of tests performed with DBFP, relative to those with venous samples (defined as 100% were 93.1% (95% CI:[84.7-97.7] and 94.4% (95% CI:[88.3-97.7], respectively. The Kappa coefficient 0.87 (95% CI:[0.80-0.94] was excellent. CONCLUSION: This study shows that DBFP specimens can be used as a cost-effective alternative sampling method for the surveillance and monitoring of CHIKV circulation and emergence in developing countries, and probably also for other arboviruses. The loss of sensitivity is insignificant and involved a very small number of patients, all with low viral loads. Whether viruses can be isolated from dried blood spots remains to be determined.

  19. Microfluidic bead-based multienzyme-nanoparticle amplification for detection of circulating tumor cells in the blood using quantum dots labels

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, He, E-mail: mzhang_he@126.com; Fu, Xin; Hu, Jiayi; Zhu, Zhenjun

    2013-05-24

    Graphical abstract: A microfluidic beads-based nucleic acid sensor for sensitive detection of circulating tumor cells (CTCs) in the blood using multienzyme-nanoparticle amplification and quantum dots labels was developed. The chip-based CTCs analysis could detect reverse transcription-polymerase chain reaction (RT-PCR) products of tumor cell as low as 1 tumor cell (e.g. CEA expressing cell) in 1 mL blood sample. This microfluidic beads-based nucleic acid sensor is a promising platform for disease-related nucleic acid molecules at the lowest level at their earliest incidence. -- Highlights: •Combination of microfluidic bead-based platform and enzyme–probe–AuNPs is proposed. •The developed nucleic acid sensor could respond to 5 fM of tumor associated DNA. •Microfluidic platform and multienzyme-labeled AuNPs greatly enhanced sensitivity. •The developed nucleic acid sensor could respond to RT-PCR products of tumor cell as low as 1 tumor cell in 1 mL blood sample. •We report a sensitive nucleic acid sensor for detection of circulating tumor cells. -- Abstract: This study reports the development of a microfluidic bead-based nucleic acid sensor for sensitive detection of circulating tumor cells in blood samples using multienzyme-nanoparticle amplification and quantum dot labels. In this method, the microbeads functionalized with the capture probes and modified electron rich proteins were arrayed within a microfluidic channel as sensing elements, and the gold nanoparticles (AuNPs) functionalized with the horseradish peroxidases (HRP) and DNA probes were used as labels. Hence, two signal amplification approaches are integrated for enhancing the detection sensitivity of circulating tumor cells. First, the large surface area of Au nanoparticle carrier allows several binding events of HRP on each nanosphere. Second, enhanced mass transport capability inherent from microfluidics leads to higher capture efficiency of targets because continuous flow within micro

  20. Mobilization of Neural Precursors in the Circulating Blood of Patients with Multiple Sclerosis

    Science.gov (United States)

    2013-09-01

    Buck DW (1997) AC133, a novel marker for human hematopoietic stem and progenitor cells. Blood 90:5002-5012. Zanotti C, Chiarini M, Serana F, Capra R...Chiarini M, Serana F, Capra R, Rottoli M, Rovaris M, Cavaletti G, Clerici R, Rezzonico M, Caimi L, Imberti L (2011) Opposite effects of interferon

  1. Enhancement of Capture Sensitivity for Circulating Tumor Cells in a Breast Cancer Patient's Blood by Silicon Nanowire Platform.

    Science.gov (United States)

    Kim, Dong-Joo; Choi, Mun-Ki; Jeong, Jin-Tak; Lim, Jung-Taek; Lee, Han-Byoel; Han, Wonshik; Lee, Sang-Kwon

    2016-04-01

    The separation of circulating tumor cells (CTCs) from the blood of cancer patients with high sensitivity is an essential technique for selecting chemotherapeutic agents at a patient-by-patient level. Recently, various research groups have reported a nanostructure-based platform for rare cell capture due to its high surface area and 3D nanotopographic features. However, evaluation of capture sensitivity based on chemical modification of the nanostructure surface has not yet been performed. Here, we evaluated the capture sensitivity for CTCs from the blood of three patients diagnosed with stage IV metastatic breast cancer by using the following three platforms: streptavidin-conjugated silicon nanowire (STR-SiNW), poly-l-lysine-coated silicon nanowire (PLL-SiNW), and poly-l-lysine-coated glass (PLL-glass). The number of evaluated CTCs on STR-SiNW, PLL-SiNW, and PLL-glass were 16.2 ± 5.5 cells, 7.3 ± 2.9 cells, and 4.7 ± 1.5 cells, respectively, per 0.5 ml. Therefore, we suggest that the STR-SiNW platform is highly adaptable for the quantitative evaluation of CTCs from the blood of cancer patients in the clinical setting.

  2. Dynamics of indicators of a metabolic exchange and condition of blood circulation of the bottom extremities after traction extension at patients with lumbar and sacral dorsopathy

    Directory of Open Access Journals (Sweden)

    Kotenko К.V.

    2013-12-01

    Full Text Available Aim: to study influence of traction therapy in a pulse mode in a complex with electrotherapy on a condition of blood circulation of the bottom extremities and level of a metabolic exchange. Material and methods. There had been examined 120 patients with a lumbar and sacral dorsopathy aged from 22 to 69 years (middle age of 49,5 years with prescription of a disease from 1 to 5 years, among them men of 34,2%, women of 65,8%. Results. The analysis of effects of various medical methods on a condition of local blood circulation in the bottom extremities showed that the most expressed its compensation is noted at complex application of mechanical pulse traction influence and electrotherapy for patients with a dorsopathy of lumbar and sacral department of a backbone that is confirmed by restoration to normal values of all indicators rheovasogramm. Conclusion. High clinical results of application of the combined medical and rehabilitation complex are based on compensation of local blood circulation that is shown in elimination of deficiency of blood supply due to improvement of a tone of arterial vessels and elimination of venous stagnation, and also due to increase of linear speed of a blood-groove and development of collateral blood circulation. Application of electrical impulse and mechanical traction influences, more at their combination promotes fermentative activity of the systems responsible for a protein exchange that is important for prevention of degenerate and dystrophic process progressing.

  3. CIRCULATING MICROPARTICLES, BLOOD CELLS, AND ENDOTHELIUM INDUCE PROCOAGULANT ACTIVITY IN SEPSIS THROUGH PHOSPHATIDYLSERINE EXPOSURE.

    Science.gov (United States)

    Zhang, Yan; Meng, Huan; Ma, Ruishuang; He, Zhangxiu; Wu, Xiaoming; Cao, Muhua; Yao, Zhipeng; Zhao, Lu; Li, Tao; Deng, Ruijuan; Dong, Zengxiang; Tian, Ye; Bi, Yayan; Kou, Junjie; Thatte, Hemant S; Zhou, Jin; Shi, Jialan

    2016-03-01

    Sepsis is invariably accompanied by altered coagulation cascade; however, the precise role of phosphatidylserine (PS) in inflammation-associated coagulopathy in sepsis has not been well elucidated. We explored the possibility of exposed PS on microparticles (MPs), blood cells, as well as on endothelium, and defined its role in procoagulant activity (PCA) in sepsis. PS-positive MPs and cells were detected by flow cytometry, while PCA was assessed with clotting time, purified coagulation complex, and fibrin formation assays. Plasma levels of PS MPs derived from platelets, leukocytes (including neutrophils, monocytes, and lymphocytes), erythrocytes, and endothelial cells were elevated by 1.49-, 1.60-, 2.93-, and 1.53-fold, respectively, in septic patients. Meanwhile, PS exposure on blood cells was markedly higher in septic patients than in controls. Additionally, we found that the endothelial cells (ECs) treated with septic serum in vitro exposed more PS than with healthy serum. Isolated MPs/blood cells from septic patients and cultured ECs treated with septic serum in vitro demonstrated significantly shortened coagulation time, greatly enhanced intrinsic/extrinsic FXa generation, and increased thrombin formation. Importantly, confocal imaging of MPs or septic serum-treated ECs identified binding sites for FVa and FXa to form prothrombinase, and further supported fibrin formation in the area where PS exposure was abundant. Pretreatment with lactadherin blocked PS on MPs/blood cells/ECs, prolonged coagulation time by at least 25%, reduced FXa/thrombin generation, and inhibited fibrin formation by approximately 85%. Our findings suggest a key role for PS exposed on MPs, blood cells, and endothelium in augmenting coagulation in sepsis. Therefore, therapies targeting PS may be of particular importance.

  4. Systematic review and meta-analysis of circulating S100B blood levels in schizophrenia.

    Directory of Open Access Journals (Sweden)

    Katina Aleksovska

    Full Text Available S100B is a calcium-binding protein secreted in central nervous system from astrocytes and other glia cells. High blood S100B levels have been linked to brain damage and psychiatric disorders. S100B levels have been reported to be higher in schizophrenics than healthy controls. To quantify the relationship between S100B blood levels and schizophrenia a systematic literature review of case-control studies published on this topic within July 3rd 2014 was carried out using three bibliographic databases: Medline, Scopus and Web of Science. Studies reporting mean and standard deviation of S100B blood levels both in cases and controls were included in the meta-analysis. The meta-Mean Ratio (mMR of S100B blood levels in cases compared to controls was used as a measure of effect along with its 95% Confidence Intervals (CI. 20 studies were included totaling for 994 cases and 785 controls. Schizophrenia patients showed 76% higher S100B blood levels than controls with mMR = 1.76 95% CI: 1.44-2.15. No difference could be found between drug-free patients with mMR = 1.84 95%CI: 1.24-2.74 and patients on antipsychotic medication with mMR = 1.75 95% CI: 1.41-2.16. Similarly, ethnicity and stage of disease didn't affect results. Although S100B could be regarded as a possible biomarker of schizophrenia, limitations should be accounted when interpreting results, especially because of the high heterogeneity that remained >70%, even after carrying out subgroups analyses. These results point out that approaches based on traditional categorical diagnoses may be too restrictive and new approaches based on the characterization of new complex phenotypes should be considered.

  5. Analysis on Mechanisms of Activating Blood Circulation and Compatible Regularity of Cinnamon Twig%桂枝活血机理及配伍规律探析*

    Institute of Scientific and Technical Information of China (English)

    徐慕鸽; 魏凯峰(通讯作者)

    2013-01-01

    This paper states the function of activating blood circulation in Cinnamon Twig, as well as the compatible regularity. The function on activating blood circulation of Cinnamon Twig is resulted from regulating body's blood, Qi and fluid. We should use it flexibly according to rational combination with blood-activating drugs, blood-enriching drugs and Qi-tonifying drugs in clinical practice.%阐述了桂枝功能与活血的关系,以及相关的配伍。认为桂枝的活血功效是通过调节机体血、气、水发挥,根据证候配伍活血药、养血药、温里药、理气药、补气药而在临床灵活使用。

  6. Potentials of the circulating pruritogenic mediator lysophosphatidic acid in development of allergic skin inflammation in mice: role of blood cell-associated lysophospholipase D activity of autotaxin.

    Science.gov (United States)

    Shimizu, Yoshibumi; Morikawa, Yoshiyuki; Okudaira, Shinichi; Kimoto, Shigenobu; Tanaka, Tamotsu; Aoki, Junken; Tokumura, Akira

    2014-05-01

    Itching and infiltration of immune cells are important hallmarks of atopic dermatitis (AD). Although various studies have focused on peripheral mediator-mediated mechanisms, systemic mediator-mediated mechanisms are also important in the pathogenesis and development of AD. Herein, we found that intradermal injection of lysophosphatidic acid (LPA), a bioactive phospholipid, induces scratching responses by Institute of Cancer Research mice through LPA1 receptor- and opioid μ receptor-mediating mechanisms, indicating its potential as a pruritogen. The circulating level of LPA in Naruto Research Institute Otsuka Atrichia mice, a systemic AD model, with severe scratching was found to be higher than that of control BALB/c mice, probably because of the increased lysophospholipase D activity of autotaxin (ATX) in the blood (mainly membrane associated) rather than in plasma (soluble). Heparan sulfate proteoglycan was shown to be involved in the association of ATX with blood cells. The sequestration of ATX protein on the blood cells by heparan sulfate proteoglycan may accelerate the transport of LPA to the local apical surface of vascular endothelium with LPA receptors, promoting the hyperpermeability of venules and the pathological uptake of immune cells, aggravating lesion progression and itching in Naruto Research Institute Otsuka Atrichia mice.

  7. Transition from fetal to neonatal circulation: Modeling the effect of umbilical cord clamping.

    Science.gov (United States)

    Yigit, Mehmet B; Kowalski, William J; Hutchon, David J R; Pekkan, Kerem

    2015-06-25

    Hemodynamics of the fetal to neonatal transition are orchestrated through complex physiological changes and results in cardiovascular adaptation to the adult biventricular circulation. Clinical practice during this critical period can influence vital organ physiology for normal newborns, premature babies and congenital heart defect patients. Particularly, the timing of the cord clamping procedure, immediate (ICC) vs. delayed cord clamping (DCC), is hypothesized to be an important factor for the transitory fetal hemodynamics. The clinical need for a quantitative understanding of this physiology motivated the development of a lumped parameter model (LPM) of the fetal cardio-respiratory system covering the late-gestation to neonatal period. The LPM was validated with in vivo clinical data and then used to predict the effects of cord clamping procedures on hemodynamics and vital gases. Clinical time-dependent resistance functions to simulate the vascular changes were introduced. For DCC, placental transfusion (31.3 ml) increased neonatal blood volume by 11.7%. This increased blood volume is reflected in an increase in preload pressures by ~20% compared to ICC, which in turn increased the cardiac output (CO) by 20% (COICC=993 ml/min; CODCC=1197 ml/min). Our model accurately predicted dynamic flow patterns in vivo. DCC was shown to maintain oxygenation if the onset of pulmonary respiration was delayed or impaired. On the other hand, a significant 25% decrease in oxygen saturations was observed when applying ICC under the same physiological conditions. We conclude that DCC has a significant impact on newborn hemodynamics, mainly because of the improved blood volume and the sustained placental respiration.

  8. NUMERICAL MODELLING OF THE QUASI-GLOBAL OCEAN CIRCULATION BASED ON POM

    Institute of Scientific and Technical Information of China (English)

    XIA Chang-shui; QIAO Fang-li; ZHANG Qing-hua; YUAN Ye-li

    2004-01-01

    A free surface quasi-global ocean circulation model,Princeton Ocean Model(POM),was adopted to simulate the climatological circulation.The horizontal resolution of the model was 1/2°×1/2° with 16 vertical sigma layers.The initial temperature and salinity fields of the model were interpolated from the Levitus data,and the COADS(Comprehensive Ocean-Atmosphere Data Set)monthly mean SST and wind fields were used as the surface forcing.The integral time length is 6a.The main general circulation components such as the equatorial current,the equatorial undercurrent,the south and north equatorial currents,the Antarctic Circumpolar Current(ACC),the Kuroshio and the Gulf Stream were well reconstructed.The volume transports of PN section and ACC agree well with the estimations on field survey.Up to now there is no global or quasi-global circulation model results using POM in literature.Our results demonstrate that POM has sound ability to simulate the coastal circulation as well as the general ocean circulation.And this result can provide open boundary conditions for fine resolution regional ocean circulation models.

  9. A Mathematical Model for Differential—Velocity Circulating Fluidized Bed Boiler

    Institute of Scientific and Technical Information of China (English)

    LiZhao; XiangdongXu

    1999-01-01

    The scheme of differential-velocity circulating fluidized bed was put forward by Thermal Engineering Department of Tsinghua university in 1992 and got patent simultaneously.An internal bed material circulation in combustor can be established by the discrepancy of entrainment at different air velocity,and separates the combustor into three different velocity regions,which constitutes the differential-velocity inside circulation.Mathematical modeling and simulation may facilitate understanding,Development and operation of this new process.Here cell model method was adopted to set up the model.

  10. Development of a High-Resolution Coastal Circulation Model for the Ocean Observatory in Lunenburg Bay

    Institute of Scientific and Technical Information of China (English)

    WANG Liang; SHENG Jinyu

    2005-01-01

    An advanced ocean observatory has been established in Lunenburg Bay of Nova Scotia, Canada as part of an interdisciplinary research project of marine environmental prediction. The development of a high-resolution coastal circulation model is one of important components of the observatory. The model horizontal resolution is 60 m and the vertical resolution is about 1 m. The coastal circulation model is used to simulate the semi-diurnal tidal circulation and associated nonlinear dynamics with the M2 forcing specified at the model open boundaries. The model is also used to simulate the storm-induced circulation in the bay during Hurricane Juan in September 2003, with the model forcing to be the combination of tides and remotely generated waves specified at the model open boundaries and wind stress applied at the sea surface. The model results demonstrate strong interactions between the local wind stress, tidal forcing, and remotely generated waves during this period. Comparison of model results with the surface elevation and current observations demonstrates that the coastal circulation model has reasonable skills in simulating the tidal and storm-induced circulation in the bay.

  11. Multi-year predictability in a coupled general circulation model

    Energy Technology Data Exchange (ETDEWEB)

    Power, Scott; Colman, Rob [Bureau of Meteorology Research Centre, Melbourne, VIC (Australia)

    2006-02-01

    Multi-year to decadal variability in a 100-year integration of a BMRC coupled atmosphere-ocean general circulation model (CGCM) is examined. The fractional contribution made by the decadal component generally increases with depth and latitude away from surface waters in the equatorial Indo-Pacific Ocean. The relative importance of decadal variability is enhanced in off-equatorial ''wings'' in the subtropical eastern Pacific. The model and observations exhibit ''ENSO-like'' decadal patterns. Analytic results are derived, which show that the patterns can, in theory, occur in the absence of any predictability beyond ENSO time-scales. In practice, however, modification to this stochastic view is needed to account for robust differences between ENSO-like decadal patterns and their interannual counterparts. An analysis of variability in the CGCM, a wind-forced shallow water model, and a simple mixed layer model together with existing and new theoretical results are used to improve upon this stochastic paradigm and to provide a new theory for the origin of decadal ENSO-like patterns like the Interdecadal Pacific Oscillation and Pacific Decadal Oscillation. In this theory, ENSO-driven wind-stress variability forces internal equatorially-trapped Kelvin waves that propagate towards the eastern boundary. Kelvin waves can excite reflected internal westward propagating equatorially-trapped Rossby waves (RWs) and coastally-trapped waves (CTWs). CTWs have no impact on the off-equatorial sub-surface ocean outside the coastal wave guide, whereas the RWs do. If the frequency of the incident wave is too high, then only CTWs are excited. At lower frequencies, both CTWs and RWs can be excited. The lower the frequency, the greater the fraction of energy transmitted to RWs. This lowers the characteristic frequency of variability off the equator relative to its equatorial counterpart. Both the eastern boundary interactions and the accumulation of

  12. [Detection of fetal nucleated red blood cells in the maternal circulation by Kleihauer test].

    Science.gov (United States)

    Liu, Wei-Yu; Jin, Chun-Lian; Liu, Li-Ying; Lin, Chang-Kun; Wang, Yan; Sun, Kai-Lai

    2007-03-01

    Maternal blood was obtained from 18 pregnant women at 7 to 25 weeks of gestation. After Percoll discontinuous density gradient centifugation, the fetal nucleated red blood cells (NRBCs) were stained with Kleihauer test. Positive fetal cells appeared with an intense red cytoplasmic staining while maternal cells with adult haemoglobin were colourless. Individual positive NRBC was collected by micromanipulator and whole genome amplification was then performed to determine sex and STR status. This allowed the simultaneous verification of the fetal origin of NRBC and prenatal diagnosis of genetic diseases. The non-invasive prenatal genetic diagnosis of 9 fetuses at high risk of Duchenne muscular dystrophy (DMD) was completed successfully. The Kleihauer test is a rapid, simple and direct chemical staining method to select fetal cells and can be applied in prenatal diagnosis.

  13. Precision of a new bedside method for estimation of the circulating blood volume

    DEFF Research Database (Denmark)

    Christensen, P; Eriksen, B; Henneberg, S W

    1993-01-01

    and after ventilation with a gas mixture containing 20-50 ml of CO for a period of 10-15 min. A special Water's to and fro system was designed in order to avoid any leakage when measuring during intermittent positive pressure ventilation (IPPV). Blood samples were taken before and immediately after......, determination of CBV can be performed with an amount of CO that gives rise to a harmless increase in the carboxyhemoglobin concentration.(ABSTRACT TRUNCATED AT 250 WORDS)...

  14. Accurate measurement of circulating mitochondrial DNA content from human blood samples using real-time quantitative PCR.

    Science.gov (United States)

    Ajaz, Saima; Czajka, Anna; Malik, Afshan

    2015-01-01

    We describe a protocol to accurately measure the amount of human mitochondrial DNA (MtDNA) in peripheral blood samples which can be modified to quantify MtDNA from other body fluids, human cells, and tissues. This protocol is based on the use of real-time quantitative PCR (qPCR) to quantify the amount of MtDNA relative to nuclear DNA (designated the Mt/N ratio). In the last decade, there have been increasing numbers of studies describing altered MtDNA or Mt/N in circulation in common nongenetic diseases where mitochondrial dysfunction may play a role (for review see Malik and Czajka, Mitochondrion 13:481-492, 2013). These studies are distinct from those looking at genetic mitochondrial disease and are attempting to identify acquired changes in circulating MtDNA content as an indicator of mitochondrial function. However, the methodology being used is not always specific and reproducible. As more than 95 % of the human mitochondrial genome is duplicated in the human nuclear genome, it is important to avoid co-amplification of nuclear pseudogenes. Furthermore, template preparation protocols can also affect the results because of the size and structural differences between the mitochondrial and nuclear genomes. Here we describe how to (1) prepare DNA from blood samples; (2) pretreat the DNA to prevent dilution bias; (3) prepare dilution standards for absolute quantification using the unique primers human mitochondrial genome forward primer (hMitoF3) and human mitochondrial genome reverse primer(hMitoR3) for the mitochondrial genome, and human nuclear genome forward primer (hB2MF1) and human nuclear genome reverse primer (hB2MR1) primers for the human nuclear genome; (4) carry out qPCR for either relative or absolute quantification from test samples; (5) analyze qPCR data; and (6) calculate the sample size to adequately power studies. The protocol presented here is suitable for high-throughput use.

  15. Time-evolution of in vivo protein corona onto blood-circulating PEGylated liposomal doxorubicin (DOXIL) nanoparticles

    Science.gov (United States)

    Hadjidemetriou, Marilena; Al-Ahmady, Zahraa; Kostarelos, Kostas

    2016-03-01

    Nanoparticles (NPs) are instantly modified once injected in the bloodstream because of their interaction with the blood components. The spontaneous coating of NPs by proteins, once in contact with biological fluids, has been termed the `protein corona' and it is considered to be a determinant factor for the pharmacological, toxicological and therapeutic profile of NPs. Protein exposure time is thought to greatly influence the composition of protein corona, however the dynamics of protein interactions under realistic, in vivo conditions remain unexplored. The aim of this study was to quantitatively and qualitatively investigate the time evolution of in vivo protein corona, formed onto blood circulating, clinically used, PEGylated liposomal doxorubicin. Protein adsorption profiles were determined 10 min, 1 h and 3 h post-injection of liposomes into CD-1 mice. The results demonstrated that a complex protein corona was formed as early as 10 min post-injection. Even though the total amount of protein adsorbed did not significantly change over time, the fluctuation of protein abundances observed indicated highly dynamic protein binding kinetics.Nanoparticles (NPs) are instantly modified once injected in the bloodstream because of their interaction with the blood components. The spontaneous coating of NPs by proteins, once in contact with biological fluids, has been termed the `protein corona' and it is considered to be a determinant factor for the pharmacological, toxicological and therapeutic profile of NPs. Protein exposure time is thought to greatly influence the composition of protein corona, however the dynamics of protein interactions under realistic, in vivo conditions remain unexplored. The aim of this study was to quantitatively and qualitatively investigate the time evolution of in vivo protein corona, formed onto blood circulating, clinically used, PEGylated liposomal doxorubicin. Protein adsorption profiles were determined 10 min, 1 h and 3 h post

  16. Circulating Fibronectin Controls Tumor Growth

    Directory of Open Access Journals (Sweden)

    Anja von Au

    2013-08-01

    Full Text Available Fibronectin is ubiquitously expressed in the extracellular matrix, and experimental evidence has shown that it modulates blood vessel formation. The relative contribution of local and circulating fibronectin to blood vessel formation in vivo remains unknown despite evidence for unexpected roles of circulating fibronectin in various diseases. Using transgenic mouse models, we established that circulating fibronectin facilitates the growth of bone metastases by enhancing blood vessel formation and maturation. This effect is more relevant than that of fibronectin produced by endothelial cells and pericytes, which only exert a small additive effect on vessel maturation. Circulating fibronectin enhances its local production in tumors through a positive feedback loop and increases the amount of vascular endothelial growth factor (VEGF retained in the matrix. Both fibronectin and VEGF then cooperate to stimulate blood vessel formation. Fibronectin content in the tumor correlates with the number of blood vessels and tumor growth in the mouse models. Consistent with these results, examination of three separate arrays from patients with breast and prostate cancers revealed that a high staining intensity for fibronectin in tumors is associated with increased mortality. These results establish that circulating fibronectin modulates blood vessel formation and tumor growth by modifying the amount of and the response to VEGF. Furthermore, determination of the fibronectin content can serve as a prognostic biomarker for breast and prostate cancers and possibly other cancers.

  17. Circulating micro-RNAs as potential blood-based markers for early stage breast cancer detection.

    Directory of Open Access Journals (Sweden)

    Michael G Schrauder

    Full Text Available INTRODUCTION: MicroRNAs (miRNAs, miRs are a class of small, non-coding RNA molecules with relevance as regulators of gene expression thereby affecting crucial processes in cancer development. MiRNAs offer great potential as biomarkers for cancer detection due to their remarkable stability in blood and their characteristic expression in many different diseases. We investigated whether microarray-based miRNA profiling on whole blood could discriminate between early stage breast cancer patients and healthy controls. METHODS: We performed microarray-based miRNA profiling on whole blood of 48 early stage breast cancer patients at diagnosis along with 57 healthy individuals as controls. This was followed by a real-time semi-quantitative Polymerase Chain Reaction (RT-qPCR validation in a separate cohort of 24 early stage breast cancer patients from a breast cancer screening unit and 24 age matched controls using two differentially expressed miRNAs (miR-202, miR-718. RESULTS: Using the significance level of p<0.05, we found that 59 miRNAs were differentially expressed in whole blood of early stage breast cancer patients compared to healthy controls. 13 significantly up-regulated miRNAs and 46 significantly down-regulated miRNAs in our microarray panel of 1100 miRNAs and miRNA star sequences could be detected. A set of 240 miRNAs that was evaluated by radial basis function kernel support vector machines and 10-fold cross validation yielded a specificity of 78.8%, and a sensitivity of 92.5%, as well as an accuracy of 85.6%. Two miRNAs were validated by RT-qPCR in an independent cohort. The relative fold changes of the RT-qPCR validation were in line with the microarray data for both miRNAs, and statistically significant differences in miRNA-expression were found for miR-202. CONCLUSIONS: MiRNA profiling in whole blood has potential as a novel method for early stage breast cancer detection, but there are still challenges that need to be addressed to

  18. Effect of Chinese Drugs for Promoting Blood Circulation and Eliminating Blood Stasis on Vascular Endothelial Growth Factor Expression in Rabbits with Glucocorticoid-induced Ischemic Necrosis of Femoral Head

    Institute of Scientific and Technical Information of China (English)

    QI Zhen-xi; CHEN Lei

    2009-01-01

    Objective:To probe into the mechanism of Chinese drugs for promoting blood circulation and eliminating blood stasis in the prevention and treatment of glueocorticoid-induced ischemic necrosis of femoral head.Methods: Thirty New Zealand adult white rabbits were randomly divided into a normal control group (n=5)and a model group (n=25). Hydroxyprednisone acetate was intramuscularly administered to the rabbits in the model group in a dosage of 7.5 mg/kg, twice per week for 6 weeks, to induce ischemic necrosis of femoral head and normal saline of the equal volume was intramuscularly administered to the rabbits in the normal control group, twice per week for 6 weeks. Then, the 5 rabbits from the normal control group and 5 rabbits selected randomly from the model group were sacrificed and the changes in histopathology and the expression of Vascular Endothelial Growth Factor (VEGF) were observed. The other 20 rabbits in the model group were randomly divided into the treatment group 1 and the treatment group 2, and the control group 1 and the control group 2, 5 rabbits in every group. Taohong Siwu Tang (桃红四物汤 Decoction of Four Drugs with Addition of Peach Kernel and Safflower) was orally administered to the rabbits in the treatment group 1 and the treatment group 2 in a dosage of 7 ml/kg, once daily and normal saline of the equal volume was orally administered to the rabbits in the control groupl and the control group, 2 once daily. After 10 weeks the rabbits in the treatment group 1 and the control group 1 were sacrificed and after 13 weeks the rabbits in the treatment group 2 and the control group 2 were sacrificed, and the expression of VEGF was detected in these rabbits. Results: The expression of VEGF was significantly enhanced in rabbits of the model group as compared with the normal control group (P<0.01), and gradually reduced with the lapse of time. The expression of VEGF in the control groups was significantly reduced as compared with the treatment

  19. A Three-Box Model of Thermohaline Circulation under the Energy Constraint

    Institute of Scientific and Technical Information of China (English)

    SHEN Yang; GUAN Yu-Ping; LIANG Chu-Jin; CHEN Da-Ke

    2011-01-01

    The driving mechanism of thermohaline circulation is still a controversial topic in physical oceanography. Classic theory is based on Stommel's two-box model under buoyancy constraint. Recently, Guan and Huang proposed a new viewpoint in the framework of energy constraint with a two-box model. We extend it to a three-box model,including the effect of wind-driven circulation. Using this simple model, we further study how ocean mixing impacts on thermohaline circulation under the energy constraint.%@@ The driving mechanism of thermohaline circulation is still a controversial topic in physical oceanography.Classic theory is based on Stommel's two-box model under buoyancy constraint.Recently,Guan and Huang proposed a new viewpoint in the framework of energy constraint with a two-box model.We extend it to a three-box model,including the effect of wind-driven circulation.Using this simple model,we further study how ocean mixing impacts on thermohaline circulation under the energy constraint.

  20. Meridional overturning circulation: stability and ocean feedbacks in a box model

    CERN Document Server

    Cimatoribus, Andrea A; Dijkstra, Henk A

    2012-01-01

    A box model of the inter-hemispheric Atlantic meridional overturning circulation is developed, including a variable pycnocline depth for the tropical and subtropical regions. The circulation is forced by winds over a periodic channel in the south and by freshwater forcing at the surface. The model is aimed at investigating the ocean feedbacks related to perturbations in freshwater forcing from the atmosphere, and to changes in freshwater transport in the ocean. These feedbacks are closely connected with the stability properties of the meridional overturning circulation, in particular in response to freshwater perturbations.

  1. A STUDY OF THE CIRCULATION, BLOOD PRESSURE, AND RESPIRATION OF SHARKS.

    Science.gov (United States)

    Lyon, E P

    1926-01-04

    The average branchial blood pressure in sand sharks was 32 mm. of mercury. The highest recorded in a resting animal was 43 mm. The average dorsal or systemic pressure was 23.3 mm.; highest 30 mm. The ratio of branchial to systemic pressure is about 3 to 2. The pressure in both systems keeps up well under trauma; but under experimental conditions, with or without manipulation of viscera, slowly falls after several hours. It rises with muscular effort, and a long rise usually follows stoppage of struggling. It rises when sodium carbonate is injected. The adrenalin curve resembles that in a mammal. Spontaneous rises and falls not attributable to the heart occur. Light in some animals increases blood pressure. It is suspected that these fishes have a vasomotor apparatus. The heart rate except after trauma is practically always the same as the respiration rate, and there is some reason for believing that the heart rate is determined by the respiration rate. When not in step with respiration, the heart is slower and often in a simple ratio with respiration. The heart is inhibited by all sorts of stimuli applied practically anywhere (except to the liver?). This effect is abolished by atropin. Respiration is faster in small animals and averages 24 per minute. Respiration slowly decreases in strength with little change in rate. Usually respiration ceases long before the heart stops.

  2. Development of an Automated and Sensitive Microfluidic Device for Capturing and Characterizing Circulating Tumor Cells (CTCs from Clinical Blood Samples.

    Directory of Open Access Journals (Sweden)

    Priya Gogoi

    Full Text Available Current analysis of circulating tumor cells (CTCs is hindered by sub-optimal sensitivity and specificity of devices or assays as well as lack of capability of characterization of CTCs with clinical biomarkers. Here, we validate a novel technology to enrich and characterize CTCs from blood samples of patients with metastatic breast, prostate and colorectal cancers using a microfluidic chip which is processed by using an automated staining and scanning system from sample preparation to image processing. The Celsee system allowed for the detection of CTCs with apparent high sensitivity and specificity (94% sensitivity and 100% specificity. Moreover, the system facilitated rapid capture of CTCs from blood samples and also allowed for downstream characterization of the captured cells by immunohistochemistry, DNA and mRNA fluorescence in-situ hybridization (FISH. In a subset of patients with prostate cancer we compared the technology with a FDA-approved CTC device, CellSearch and found a higher degree of sensitivity with the Celsee instrument. In conclusion, the integrated Celsee system represents a promising CTC technology for enumeration and molecular characterization.

  3. Time-evolution of in vivo protein corona onto blood-circulating PEGylated liposomal doxorubicin (DOXIL) nanoparticles.

    Science.gov (United States)

    Hadjidemetriou, Marilena; Al-Ahmady, Zahraa; Kostarelos, Kostas

    2016-04-07

    Nanoparticles (NPs) are instantly modified once injected in the bloodstream because of their interaction with the blood components. The spontaneous coating of NPs by proteins, once in contact with biological fluids, has been termed the 'protein corona' and it is considered to be a determinant factor for the pharmacological, toxicological and therapeutic profile of NPs. Protein exposure time is thought to greatly influence the composition of protein corona, however the dynamics of protein interactions under realistic, in vivo conditions remain unexplored. The aim of this study was to quantitatively and qualitatively investigate the time evolution of in vivo protein corona, formed onto blood circulating, clinically used, PEGylated liposomal doxorubicin. Protein adsorption profiles were determined 10 min, 1 h and 3 h post-injection of liposomes into CD-1 mice. The results demonstrated that a complex protein corona was formed as early as 10 min post-injection. Even though the total amount of protein adsorbed did not significantly change over time, the fluctuation of protein abundances observed indicated highly dynamic protein binding kinetics.

  4. Effects of 5-HT1B/1D receptor agonist rizatriptan on cerebral blood flow and blood volume in normal circulation.

    Science.gov (United States)

    Okazawa, Hidehiko; Tsuchida, Tatsuro; Pagani, Marco; Mori, Tetsuya; Kobayashi, Masato; Tanaka, Fumiko; Yonekura, Yoshiharu

    2006-01-01

    To investigate the vasoconstrictor effect of 5-hydroxytryptamine (5-HT1B/1D) receptor agonists for migraine treatment, changes in cerebral blood flow (CBF) and blood volume induced by rizatriptan were assessed by positron emission tomography (PET). Eleven healthy volunteers underwent PET studies before and after rizatriptan administration. Dynamic PET data were acquired after bolus injection of H2(15)O to analyze CBF and arterial-to-capillary blood volume (V0) images using the three-weighted integral method. After a baseline scan, three further acquisitions were performed at 40 to 50, 60 and 70 to 80 mins after drug administration. Global and regional differences in CBF and V0 between conditions were compared using absolute values in the whole brain and cortical regions, as well as statistical parametric mapping (SPM) analysis. The global and regional values for CBF and V0 decreased significantly after rizatriptan administration compared with the baseline condition. However, both values recovered to baseline within 80 mins after treatment. The maximal reduction in global CBF and V0 was approximately 13% of baseline value. The greatest decrease in CBF was observed approximately 60 mins after drug administration, whereas the maximal reduction in V0 was observed approximately 5 mins earlier. Statistical parametric mapping did not highlight any regional differences between conditions. Thus, in brain circulation, rizatriptan caused significant CBF and V0 decreases, which are consistent with the vasoconstrictor effect of triptans on the large cerebral arteries. The gradual recovery in the late phase from the maximal CBF and V0 decrease suggests that rizatriptan does not affect the cerebral autoregulatory response in small arteries induced by CBF reduction.

  5. Aluminium in an ocean general circulation model compared with the West Atlantic Geotraces cruises

    NARCIS (Netherlands)

    van Hulten, M. M. P.; Sterl, A.; Tagliabue, A.; Dutay, J. -C.; Gehlen, M.; de Baar, H. J. W.; Middag, R.

    2013-01-01

    A model of aluminium has been developed and implemented in an Ocean General Circulation Model (NEMO-PISCES). In the model, aluminium enters the ocean by means of dust deposition. The internal oceanic processes are described by advection, mixing and reversible scavenging. The model has been evaluated

  6. Significant biochemical, biophysical and metabolic diversity in circulating human cord blood reticulocytes.

    Directory of Open Access Journals (Sweden)

    Benoît Malleret

    Full Text Available BACKGROUND: The transition from enucleated reticulocytes to mature normocytes is marked by substantial remodeling of the erythrocytic cytoplasm and membrane. Despite conspicuous changes, most studies describe the maturing reticulocyte as a homogenous erythropoietic cell type. While reticulocyte staging based on fluorescent RNA stains such as thiazole orange have been useful in a clinical setting; these 'sub-vital' stains may confound delicate studies on reticulocyte biology and may preclude their use in heamoparasite invasion studies. DESIGN AND METHODS: Here we use highly purified populations of reticulocytes isolated from cord blood, sorted by flow cytometry into four sequential subpopulations based on transferrin receptor (CD71 expression: CD71high, CD71medium, CD71low and CD71negative. Each of these subgroups was phenotyped in terms of their, morphology, membrane antigens, biomechanical properties and metabolomic profile. RESULTS: Superficially CD71high and CD71medium reticulocytes share a similar gross morphology (large and multilobular when compared to the smaller, smooth and increasingly concave reticulocytes as seen in the in the CD71low and CD71negativesamples. However, between each of the four sample sets we observe significant decreases in shear modulus, cytoadhesive capacity, erythroid receptor expression (CD44, CD55, CD147, CD235R, and CD242 and metabolite concentrations. Interestingly increasing amounts of boric acid was found in the mature reticulocytes. CONCLUSIONS: Reticulocyte maturation is a dynamic and continuous process, confounding efforts to rigidly classify them. Certainly this study does not offer an alternative classification strategy; instead we used a nondestructive sampling method to examine key phenotypic changes of in reticulocytes. Our study emphasizes a need to focus greater attention on reticulocyte biology.

  7. Apoptosis-related deregulation of proteolytic activities and high serum levels of circulating nucleosomes and DNA in blood correlate with breast cancer progression

    Directory of Open Access Journals (Sweden)

    Kasimir-Bauer Sabine

    2011-01-01

    Full Text Available Abstract Background As cell-free circulating DNA exists predominantly as mono- and oligonucleosomes, the focus of the current study was to examine the interplay of circulating nucleosomes, DNA, proteases and caspases in blood of patients with benign and malignant breast diseases. Methods The concentrations of cell-free DNA and nucleosomes as well as the protease and caspase activities were measured in serum of patients with benign breast disease (n = 20, primary breast cancer (M0, n = 31, metastatic breast cancer (M1, n = 32, and healthy individuals (n = 28 by PicoGreen, Cell Death Detection ELISA, Protease Fluorescent Detection Kit and Caspase-Glo®3/7 Assay, respectively. Results Patients with benign and malignant tumors had significantly higher levels of circulating nucleic acids in their blood than healthy individuals (p = 0.001, p = 0.0001, whereas these levels could not discriminate between benign and malignant lesions. Our analyses of all serum samples revealed significant correlations of circulating nucleosome with DNA concentrations (p = 0.001, nucleosome concentrations with caspase activities (p = 0.008, and caspase with protease activities (p = 0.0001. High serum levels of protease and caspase activities associated with advanced tumor stages (p = 0.009. Patients with lymph node-positive breast cancer had significantly higher nucleosome levels in their blood than node-negative patients (p = 0.004. The presence of distant metastases associated with a significant increase in serum nucleosome (p = 0.01 and DNA levels (p = 0.04, and protease activities (p = 0.008. Conclusion Our findings demonstrate that high circulating nucleic acid concentrations in blood are no indicators of a malignant breast tumor. However, the observed changes in apoptosis-related deregulation of proteolytic activities along with the elevated serum levels of nucleosomes and DNA in blood are linked to breast cancer progression.

  8. Mechanisms of adaptation of the hepatic vasculature to the deteriorating conditions of blood circulation in liver cirrhosis

    Institute of Scientific and Technical Information of China (English)

    Dmitry; Victorovich; Garbuzenko; Nikolay; Olegovich; Arefyev; Dmitry; Vladimirovich; Belov

    2016-01-01

    Pub Med, EMBASE, Orphanet, MIDLINE, Google Scholar and Cochrane Library were searched for articles published between 1983 and 2015. Relevant articles were selected by using the following terms: "Liver cirrhosis", "Endothelial dysfunction", "Sinusoidal remodeling", "Intrahepatic angiogenesis" and "Pathogenesis of portal hypertension". Then the reference lists of identified articles were searched for other relevant publications as well. Besides gross hepatic structural disorders related to diffuse fibrosis and formation of regenerative nodules, the complex morphofunctional rearrangement of the hepatic microvascular bed and intrahepatic angiogenesis also play important roles in hemodynamic disturbances in liver cirrhosis. It is characterized by endothelial dysfunction and impaired paracrine interaction between activated stellate hepatocytes and sinusoidal endotheliocytes, sinusoidal remodeling and capillarization, as well as development of the collateral microcirculation. In spite of the fact that complex morphofunctional rearrangement of the hepatic microvascular bed and intrahepatic angiogenesis in liver cirrhosis are the compensatory-adaptive reaction to the deteriorating conditions of blood circulation, they contribute to progression of disease and development of serious complications, in particular, related to portal hypertension.Pub Med,EMBASE,Orphanet,MIDLINE,Google Scholar and Cochrane Library were searched for articles published between 1983 and 2015.Relevant articles were selected by using the following terms:"Liver cirrhosis","Endothelial dysfunction","Sinusoidal remodeling","Intrahepatic angiogenesis"and"Pathogenesis of portal hypertension".Then the reference lists of identified articles were searched for other relevant publications as well.Besides gross hepatic structural disorders related to diffuse fibrosis and formation of regenerative nodules,the complex morphofunctional rearrangement of the hepatic microvascular bed and intrahepatic angiogenesis also

  9. The response of Mediterranean thermohaline circulation to climate change: a minimal model

    OpenAIRE

    Meijer, P.Th.; H. A. Dijkstra

    2009-01-01

    Physics-based understanding of the effects of paleoclimate and paleogeography on the thermohaline circulation of the Mediterranean Sea requires an ocean model capable of long integrations and involving a minimum of assumptions about the atmospheric forcing. Here we examine the sensitivity of the deep circulation in the eastern Mediterranean basin to changes in atmospheric forcing, considered a key factor in the deposition of organic-rich sediments (sapropels). To this extent we explore the se...

  10. Bioengineering of Improved Biomaterials Coatings for Extracorporeal Circulation Requires Extended Observation of Blood-Biomaterial Interaction under Flow

    Directory of Open Access Journals (Sweden)

    Kris N. J. Stevens

    2007-01-01

    Full Text Available Extended use of cardiopulmonary bypass (CPB systems is often hampered by thrombus formation and infection. Part of these problems relates to imperfect hemocompatibility of the CPB circuitry. The engineering of biomaterial surfaces with genuine long-term hemocompatibility is essentially virgin territory in biomaterials science. For example, most experiments with the well-known Chandler loop model, for evaluation of blood-biomaterial interactions under flow, have been described for a maximum duration of 2 hours only. This study reports a systematic evaluation of two commercial CPB tubings, each with a hemocompatible coating, and one uncoated control. The experiments comprised (i testing over 5 hours under flow, with human whole blood from 4 different donors; (ii measurement of essential blood parameters of hemocompatibility; (iii analysis of the luminal surfaces by scanning electron microscopy and thrombin generation time measurements. The dataset indicated differences in hemocompatibility of the tubings. Furthermore, it appeared that discrimination between biomaterial coatings can be made only after several hours of blood-biomaterial contact. Platelet counting, myeloperoxidase quantification, and scanning electron microscopy proved to be the most useful methods. These findings are believed to be relevant with respect to the bioengineering of extracorporeal devices that should function in contact with blood for extended time.

  11. Comprehensive Mathematical Model for Coal Combustion in a Circulating Fluidized Bed Combustor

    Institute of Scientific and Technical Information of China (English)

    金晓钟; 吕俊复; 杨海瑞; 刘青; 岳光溪; 冯俊凯

    2001-01-01

    Char combustion is on a special reducing condition in the dense bed of a circulating fluidized bedcombustor. Experimental findings were used to develop a comprehensive mathematical model to simulate thehydrodynamic and combustion processes in a circulating fluidized bed combustor. In the model, gas-solidinteraction was used to account for the mass transfer between the bubble phase and the emulsion phase in thedense bed, which contributes to the reducing atmosphere in the dense bed. A core-annular structure wasassumed in the dilute area rather than a one-dimensional model. The submodels were combined to build thecomprehensive model to analyze the combustion in a circulating fluidized bed combustor and the effect ofoperating parameters on the coal combustion. The model predictions agree well with experimental results.

  12. Wind-Driven Ocean Circulation in Shallow Water Lattice Boltzmann Model

    Institute of Scientific and Technical Information of China (English)

    ZHONG Linhao; FENG Shide; GAO Shouting

    2005-01-01

    A lattice Boltzmann (LB) model with overall second-order accuracy is applied to the 1.5-layer shallow water equation for a wind-driven double-gyre ocean circulation. By introducing the second-order integral approximation for the collision operator, the model becomes fully explicit. In this case, any iterative technique is not needed. The Coriolis force and other external forces are included in the model with second-order accuracy, which is consistent with the discretized accuracy of the LB equation. The numerical results show correct physics of the ocean circulation driven by the double-gyre wind stress with different Reynolds numbers and different spatial resolutions. An intrinsic low-frequency variability of the shallow water model is also found. The wind-driven ocean circulation exhibits subannual and interannual oscillations, which are comparable to those of models in which the conventional numerical methods are used.

  13. Secondary flow structure in a model curved artery: 3D morphology and circulation budget analysis

    Science.gov (United States)

    Bulusu, Kartik V.; Plesniak, Michael W.

    2015-11-01

    In this study, we examined the rate of change of circulation within control regions encompassing the large-scale vortical structures associated with secondary flows, i.e. deformed Dean-, Lyne- and Wall-type (D-L-W) vortices at planar cross-sections in a 180° curved artery model (curvature ratio, 1/7). Magnetic resonance velocimetry (MRV) and particle image velocimetry (PIV) experiments were performed independently, under the same physiological inflow conditions (Womersley number, 4.2) and using Newtonian blood-analog fluids. The MRV-technique performed at Stanford University produced phase-averaged, three-dimensional velocity fields. Secondary flow field comparisons of MRV-data to PIV-data at various cross-sectional planes and inflow phases were made. A wavelet-decomposition-based approach was implemented to characterize various secondary flow morphologies. We hypothesize that the persistence and decay of arterial secondary flow vortices is intrinsically related to the influence of the out-of-plane flow, tilting, in-plane convection and diffusion-related factors within the control regions. Evaluation of these factors will elucidate secondary flow structures in arterial hemodynamics. Supported by the National Science Foundation under Grant Number CBET-0828903, and GW Center for Biomimetics and Bioinspired Engineering (COBRE). The MRV data were acquired at Stanford University in collaboration with Christopher Elkins and John Eaton.

  14. Evaluation of blood flow distribution asymmetry and vascular geometry in patients with Fontan circulation using 4-D flow MRI

    Energy Technology Data Exchange (ETDEWEB)

    Jarvis, Kelly; 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); Schnell, Susanne; Barker, Alex J.; Garcia, Julio; Chowdhary, Varun; Carr, James [Northwestern University, Department of Radiology, Feinberg School of Medicine, Chicago, IL (United States); Lorenz, Ramona [University Medical Center Freiburg, Department of Radiology, Freiburg (Germany); Rose, Michael [Ann and Robert H. Lurie Children' s Hospital of Chicago, Department of Medical Imaging, Chicago, IL (United States); Robinson, Joshua D. [Northwestern University, Department of Pediatrics, Feinberg School of Medicine, Chicago, IL (United States); Ann and Robert H. Lurie Children' s Hospital of Chicago, Division of Cardiology, Chicago, IL (United States); Rigsby, Cynthia K. [Northwestern University, Department of Radiology, Feinberg School of Medicine, Chicago, IL (United States); Ann and Robert H. Lurie Children' s Hospital of Chicago, Department of Medical Imaging, Chicago, IL (United States)

    2016-10-15

    Asymmetrical caval to pulmonary blood flow is suspected to cause complications in patients with Fontan circulation. The aim of this study was to test the feasibility of 4-D flow MRI for characterizing the relationship between 3-D blood flow distribution and vascular geometry. We hypothesized that both flow distribution and geometry can be calculated with low interobserver variability and will detect a direct relationship between flow distribution and Fontan geometry. Four-dimensional flow MRI was acquired in 10 Fontan patients (age: 16 ± 4 years [mean ± standard deviation], range: 9-21 years). The Fontan connection was isolated by 3-D segmentation to evaluate flow distribution from the inferior vena cava (IVC) and superior vena cava (SVC) to the left and right pulmonary arteries (LPA, RPA) and to characterize geometry (cross-sectional area, caval offset, vessel angle). Flow distribution results indicated SVC flow tended toward the RPA while IVC flow was more evenly distributed (SVC to RPA: 78% ± 28 [9-100], IVC to LPA: 54% ± 28 [4-98]). There was a significant relationship between pulmonary artery cross-sectional area and flow distribution (IVC to RPA: R{sup 2}=0.50, P=0.02; SVC to LPA: R{sup 2}=0.81, P=0.0004). Good agreement was found between observers and for flow distribution when compared to net flow values. Four-dimensional flow MRI was able to detect relationships between flow distribution and vessel geometry. Future studies are warranted to investigate the potential of patient specific hemodynamic analysis to improve diagnostic capability. (orig.)

  15. Evaluation of Two Different Analytical Methods for Circulating Tumor Cell Detection in Peripheral Blood of Patients with Primary Breast Cancer

    Directory of Open Access Journals (Sweden)

    B. A. S. Jaeger

    2014-01-01

    Full Text Available Background. Evidence is accumulating that circulating tumor cells (CTC out of peripheral blood can serve as prognostic marker not only in metastatic but also in early breast cancer (BC. Various methods are available to detect CTC. Comparisons between the different techniques, however, are rare. Material and Methods. We evaluate two different methods for CTC enrichment and detection in primary BC patients: the FDA-approved CellSearch System (CSS; Veridex, Warren, USA and a manual immunocytochemistry (MICC. The cut-off value for positivity was ≥1 CTC. Results. The two different nonoverlapping patient cohorts evaluated with one or the other method were well balanced regarding common clinical parameters. Before adjuvant CHT 21.1% (416 out of 1972 and 20.6% (247 out of 1198 of the patients were CTC-positive, while after CHT 22.5% (359 out of 1598 and 16.6% (177 out of 1066 of the patients were CTC-positive using CSS or MICC, respectively. CTC positivity rate before CHT was thus similar and not significantly different (P=0.749, while CTC positivity rate immediately after CHT was significantly lower using MICC compared to CSS (P<0.001. Conclusion. Using CSS or MICC for CTC detection, we found comparable prevalence of CTC before but not after adjuvant CHT.

  16. [Influence of mydocalm on the degree of intra-abdominal hypertension and local blood circulation in the intestinal wall in experiment].

    Science.gov (United States)

    Sapegin, V I; Sapegin, I D; Il'chenko, F N

    2014-01-01

    The effect of mydocalm (tolperison, 5 mg/kg single dose) on the dynamics of intra-abdominal hypertension (IAH), blood circulation regulation, and oxygen balance in the tissues of intestinal wall were studied in acute experiments on rabbits. Using a special stand of original design, the initial IAH level was modeled at 200 mm H2O with the subsequent stopping of further receipt of liquid during 3 hours in an elastic container in the abdominal cavity. During 3-h observation without drug administration, no changes in IAH due to the tone of muscles of the frontal abdominal wall takes place, but there is progressive deceleration of local blood flow (-35.33 + 0.99%, p < 0.01), suppressed dilation (-20.02 + 0.54%, p < 0.01) and constriction (-60.45 + 1.17%, p < 0.01) reactivity of vessels, and decreased oxygen tension (-47.18 + 0.75%, p < 0.01) in the intestinal wall at the end of experiment. The introduction of mydocalm reduces the tone of muscles of the frontal abdominal wall, which leads to a decrease in IAH (maximum effect after 1.5 hours, -20.81 + 0.84%, p < 0.01) and prevents decrease in the local blood flow (-26.77 + 0.41%, p < 0.01), suppression of dilation (-16.51 + 0.34%, p < 0.01) and constriction (-37.85 + 0.61%, p < 0.01) reactivity of vessels, and reduction in oxygen tension (-36.60 + 1.18%, p < 0.01) at the end of experiment. The administration of mydocalm can extend the limits of application of a conservative therapy for patients with IAH and to improve the results.

  17. A long term model of circulation. [human body

    Science.gov (United States)

    White, R. J.

    1974-01-01

    A quantitative approach to modeling human physiological function, with a view toward ultimate application to long duration space flight experiments, was undertaken. Data was obtained on the effect of weightlessness on certain aspects of human physiological function during 1-3 month periods. Modifications in the Guyton model are reviewed. Design considerations for bilateral interface models are discussed. Construction of a functioning whole body model was studied, as well as the testing of the model versus available data.

  18. Bioengineering of Improved Biomaterials Coatings for Extracorporeal Circulation Requires Extended Observation of Blood-Biomaterial Interaction under Flow

    OpenAIRE

    Stevens, Kris N. J.; Aldenhoff, Yvette B. J.; van der Veen, Frederik H; Maessen, Jos G.; Leo H. Koole

    2007-01-01

    Extended use of cardiopulmonary bypass (CPB) systems is often hampered by thrombus formation and infection. Part of these problems relates to imperfect hemocompatibility of the CPB circuitry. The engineering of biomaterial surfaces with genuine long-term hemocompatibility is essentially virgin territory in biomaterials science. For example, most experiments with the well-known Chandler loop model, for evaluation of blood-biomaterial interactions under flow, have be...

  19. Considerations for numerical modeling of the pulmonary circulation--a review with a focus on pulmonary hypertension.

    Science.gov (United States)

    Kheyfets, V O; O'Dell, W; Smith, T; Reilly, J J; Finol, E A

    2013-06-01

    Both in academic research and in clinical settings, virtual simulation of the cardiovascular system can be used to rapidly assess complex multivariable interactions between blood vessels, blood flow, and the heart. Moreover, metrics that can only be predicted with computational simulations (e.g., mechanical wall stress, oscillatory shear index, etc.) can be used to assess disease progression, for presurgical planning, and for interventional outcomes. Because the pulmonary vasculature is susceptible to a wide range of pathologies that directly impact and are affected by the hemodynamics (e.g., pulmonary hypertension), the ability to develop numerical models of pulmonary blood flow can be invaluable to the clinical scientist. Pulmonary hypertension is a devastating disease that can directly benefit from computational hemodynamics when used for diagnosis and basic research. In the present work, we provide a clinical overview of pulmonary hypertension with a focus on the hemodynamics, current treatments, and their limitations. Even with a rich history in computational modeling of the human circulation, hemodynamics in the pulmonary vasculature remains largely unexplored. Thus, we review the tasks involved in developing a computational model of pulmonary blood flow, namely vasculature reconstruction, meshing, and boundary conditions. We also address how inconsistencies between models can result in drastically different flow solutions and suggest avenues for future research opportunities. In its current state, the interpretation of this modeling technology can be subjective in a research environment and impractical for clinical practice. Therefore, considerations must be taken into account to make modeling reliable and reproducible in a laboratory setting and amenable to the vascular clinic. Finally, we discuss relevant existing models and how they have been used to gain insight into cardiopulmonary physiology and pathology.

  20. Effects of a chicken collagen hydrolysate on the circulation system in subjects with mild hypertension or high-normal blood pressure.

    Science.gov (United States)

    Kouguchi, Tomomi; Ohmori, Takashi; Shimizu, Muneshige; Takahata, Yoshihisa; Maeyama, Yoshiaki; Suzuki, Takuya; Morimatsu, Fumiki; Tanabe, Soichi

    2013-01-01

    We investigated the effects of a chicken collagen hydrolysate (CCH) on the circulation system in humans. A total of 58 subjects with either mild hypertension (systolic blood pressure (SBP) of 140-159 mmHg or diastolic blood pressure (DBP) 90-99 mmHg) or high-normal blood pressure (SBP 130-139 mmHg or DBP 85-89 mmHg) were assigned to two groups, one involving a placebo and the other, the test food (including CCH of 2.9 g/d). The parameters related to each subject's circulation system were monitored over the study period of 18 weeks. The Δbrachial-ankle pulse wave velocity (baPWV), an indicator of arterial stiffness and marker of vascular damage, was significantly lower in the test food group than in the placebo group during the treatment period. The blood pressure in the test food group was also significantly lower than that in the placebo group, while the serum nitrogen oxide was higher in the test food group after the treatment. These results suggest that CCH exerted modulatory effects on the human circulation system.

  1. Uncertainities in carbon dioxide radiative forcing in atmospheric general circulation models

    Energy Technology Data Exchange (ETDEWEB)

    Cess, R.D.; Zhang, M.H. (State Univ. of New York, Stony Brook, NY (United States)); Potter, G.L.; Gates, W.L.; Taylor, K.E. (Lawrence Livermore National Laboratory, CA (United States)); Colman, R.A.; Fraser, J.R.; McAvaney, B.J. (Bureau of Meterorology Research Centre, Victoria (Australia)); Dazlich, D.A.; Randall, D.A. (Colorado State Univ., Fort Collins, CO (United States)); Del Genio, A.D.; Lacis, A.A. (Goddard Institute for Space Studies, New York, NY (United States)); Esch, M.; Roeckner, E. (Max Planck Institute for Meteorology, Hamburg (Germany)); Galin, V. (Russian Academy of Sciences, Moscow (Russian Federation)); Hack, J.J.; Kiehl, J.T. (National Center for Atmospheric Research, Boulder, CO (United States)); Ingram, W.J. (Hadley Centre for Climate Prediction and Research, Berkshire (United Kingdom)); Le Treut, H.; Lli, Z.X. (Laboratoire de Meteorologie Dynamique, Paris (France)); Liang, X.Z.; Wang, W.C. (State Univ. of New York, Albany, NY (United States)); Mahfouf,

    1993-11-19

    Global warming, caused by an increase in the concentrations of greenhouse gases, is the direct result of greenhouse gas-induced radiative forcing. When a doubling of atmospheric carbon dioxide is considered, this forcing differed substantially among 15 atmospheric general circulation models. Although there are several potential causes, the largest contributor was the carbon dioxide radiation parameterizations of the models.

  2. A MODEL FOR FINE PARTICLE AGGLOMERATION IN CIRCULATING FLUIDIZED BED ABSORBERS

    Science.gov (United States)

    A model for fine particle agglomeration in circulating fluidized bed absorbers (CFBAS) has been developed. It can model the influence of different factors on agglomeration, such as the geometry of CFBAs, superficial gas velocity, initial particle size distribution, and type of ag...

  3. Numerical modeling of the winter circulation of the Gulf of Trieste (northern Adriatic

    Directory of Open Access Journals (Sweden)

    Boris PETELIN

    2006-12-01

    Full Text Available Numerical simulations of the winter circulation in and around the Gulf of Trieste are presented. The model, based on the architecture of the Princeton Ocean Model, gave reasonable results for circulation in the Gulf during the winter period, when the dominant bora wind is blowing. Three model runs with different initial and surface boundary conditions show that there is an outflow along the shallow northern coastline of the Gulf and over the surface of the major part of the area, and an inflow at depth in the central and southern parts of the Gulf. However, the variability of the temperature and salinity fields when vertical fluxes of heat and salinity are present cause a weak outflow in an area near the southern part of the Gulf, and make the general circulation pattern more complex.

  4. The response of Mediterranean thermohaline circulation to climate change: a minimal model

    Directory of Open Access Journals (Sweden)

    P. Th. Meijer

    2009-11-01

    Full Text Available Physics-based understanding of the effects of paleoclimate and paleogeography on the thermohaline circulation of the Mediterranean Sea requires an ocean model capable of long integrations and involving a minimum of assumptions about the atmospheric forcing. Here we examine the sensitivity of the deep circulation in the eastern Mediterranean basin to changes in atmospheric forcing, considered a key factor in the deposition of organic-rich sediments (sapropels. To this extent we explore the setup of an ocean general circulation model (MOMA with realistic (present-day bathymetry and highly idealized forcing. The model proves able to qualitatively capture some important features of the large-scale overturning circulation, in particular for the eastern basin. The response to (i a reduction in the imposed meridional temperature gradient, or (ii a reduction in net evaporation, proves to be non-linear and, under certain conditions, of transient nature. Consistent with previous model studies, but now based on a minimum of assumptions, we find that a reduction in net evaporation (such as due to an increase in freshwater input may halt the deep overturning circulation. The ability to perform long model integrations allows us to add the insight that, in order to have the conditions favourable for sapropel formation persist, we must also assume that the vertical mixing of water properties was reduced. The "minimal" model here presented opens the way to experiments in which one truly follows the basin circulation into, or out of, the period of sapropel formation and where forcing conditions are continously adjusted to the precession cycle.

  5. The response of Mediterranean thermohaline circulation to climate change: a minimal model

    Directory of Open Access Journals (Sweden)

    P. Th. Meijer

    2009-06-01

    Full Text Available Physics-based understanding of the effects of paleoclimate and paleogeography on the thermohaline circulation of the Mediterranean Sea requires an ocean model capable of long integrations and involving a minimum of assumptions about the atmospheric forcing. Here we examine the sensitivity of the deep circulation in the eastern Mediterranean basin to changes in atmospheric forcing, considered a key factor in the deposition of organic-rich sediments (sapropels. To this extent we explore the setup of an ocean general circulation model (MOMA with realistic (present-day bathymetry and highly idealized forcing. The model proves able to qualitatively capture some important features of the large-scale overturning circulation, in particular for the eastern basin. The response to (i a reduction in the imposed meridional temperature gradient, or (ii a reduction in net evaporation, proves to be non-linear and, under certain conditions, of transient nature. Consistent with previous model studies, but now based on a minimum of assumptions, we find that a reduction in net evaporation (such as due to an increase in freshwater input may halt the deep overturning circulation. The ability to perform long model integrations allows us to add the insight that, in order to have the conditions favourable for sapropel formation persist, we must also assume that the vertical mixing of water properties was reduced. The "minimal" model here presented opens the way to experiments in which one truly follows the basin circulation into, or out of, the period of sapropel formation and where forcing conditions are continuously adjusted to the precession cycle.

  6. The calculation of the circulation in South China Sea by a diagnostic model

    Institute of Scientific and Technical Information of China (English)

    ZHOU Weidong; YANG Yang; DONG Danpeng

    2008-01-01

    A high resolved two - dimensional linear global diagnostic model combining with the dynamical calculation is used to calculate ve- locity field in the South China Sea(SCS). The study of model results shows that eddy diffusion does not change basic structure of circulation in the SCS and does not change the direction of invasive water, but changes the value of transport considerably espe- cially in straits. The velocity field is not changed whether the wind stress is considered or not. This result shows the circulation is largely determined by a density field which well records most of the important contribution of the wind stress effect. Potential vor- ticity is calculated to testify the dynamics of the model results. The result shows that a good conservation of the nonlinear PV. This indicates most effects of the important nonlinear processes are well recorded in density and the nonlinear term is negligible so that the simplified model is reliable. The model results show the water exchanges between the SCS and open ocean or surrounding seas. Cold deep water invades through Luzon Strait and Warm shallow water is pushed out mainly through Karimata Straits. The model results also reveal the structure of the circulation in the SCS basin. In two circulations of upper and middle layers, a cyclon- ic one in the north and an anti-cyclonic one in the south, reflect the climatologic average of the circulation driven by monsoon. In the deep or bottom layer, these two circulations reflect the topography of the basin. Above the middle layer, invasive water enters westward in the north but the way of invasion of Kuroshio is not clear. Below the deep layer, a current goes down south near the east basin , and invasive water enters in the basin from the west Pacific.

  7. Quasi-hydrostatic Primitive Equations for Ocean Global Circulation Models

    Institute of Scientific and Technical Information of China (English)

    Carine LUCAS; Madalina PETCU; Antoine ROUSSEAU

    2010-01-01

    Global existence of weak and strong solutions to the quasi-hydrostatic primitive equations is studied in this paper.This model,that derives from the full non-hydrostatic model for geophysical fluid dynamics in the zero-limit of the aspect ratio,is more realistic than the classical hydrostatic model,since the traditional approximation that consists in neglecting a part of the Coriolis force is relaxed.After justifying the derivation of the model,the authors provide a rigorous proof of global existence of weak solutions,and well-posedness for strong solutions in dimension three.

  8. Preparation of Blood-Deficient Model and Research of Angelica Polysaccharide on Enriching Blood in Chickens

    OpenAIRE

    Haifeng Hou; Yongzhan Bao; Qian Li; Wanyu Shi

    2012-01-01

    In this study cyclophosphamide was used to prepare the blood-deficient model. The red blood cell count and hemoglobin content were measured. The experimental chickens presented the symptoms of blood-deficient syndrome, dullness, shrinkinginto oneself, broken winded, loose feather, waxy eyelid, and pale tongue. At the same time, red blood cell count and hemoglobin content decreased significantly. Angelica polysaccharide as the effective component of Angelica Sinensis could significantly increa...

  9. Horizontal circulation and jumps in Hamiltonian wave models

    NARCIS (Netherlands)

    Gagarina, E.; Vegt, van der J.; Bokhove, O.

    2013-01-01

    We are interested in the numerical modeling of wave-current interactions around surf zones at beaches. Any model that aims to predict the onset of wave breaking at the breaker line needs to capture both the nonlinearity of the wave and its dispersion. We have therefore formulated the Hamiltonian dyn

  10. Alpha Models for 3D Eulerian mean fluid circulation

    Energy Technology Data Exchange (ETDEWEB)

    Holm, D.D. [Los Alamos National Laboratory, Los Alamos, NM (United States). Center for Nonlinear Studies and Theoretical Division

    1999-12-01

    The study provides the known analytical properties of the alpha models, including an outline of their derivation and the associated assumptions, their simplification for the case of constant dispersion length (alpha) and their conservation properties. Interpretations of nonlinear dynamics of viscous alpha models are also showed and the differences one might expect from the dynamics of the Navier-Stokes equations are indicated.

  11. A Model Study of the Salish Sea Estuarine Circulation

    Science.gov (United States)

    2011-06-01

    Canal (HCN) to Main Basin (MB; Gregg and Pratt 2010) and South Sound to Main Basin (through Ta- coma Narrows; Seim and Gregg 1997), whereas Whidbey Basin...sortium fifth-generation Pennsylvania State University– National Center for Atmospheric Research Mesoscale Model (MM5) regional forecast model (Mass

  12. The influence of explicit tidal forcing in a climate ocean circulation model

    Institute of Scientific and Technical Information of China (English)

    YU Yi; LIU Hailong; LAN Jian

    2016-01-01

    The eight main tidal constituents have been implemented in the global ocean general circulation model with approximate 1° horizontal resolution. Compared with the observation data, the patterns of the tidal amplitudes and phases had been simulated fairly well. The responses of mean circulation, temperature and salinity are further investigated in the global sense. When implementing the tidal forcing, wind-driven circulations are reduced, especially those in coastal regions. It is also found that the upper cell transport of the Atlantic meridional overturning circulation (AMOC) reduces significantly, while its deep cell transport is slightly enhanced from 9×106 m3/s to 10×106 m3/s. The changes of circulations are all related to the increase of a bottom friction and a vertical viscosity due to the tidal forcing. The temperature and salinity of the model are also significantly affected by the tidal forcing through the enhanced bottom friction, mixing and the changes in mean circulation. The largest changes occur in the coastal regions, where the water is cooled and freshened. In the open ocean, the changes are divided into three layers: cooled and freshened on the surface and below 3 000 m, and warmed and salted in the middle in the open ocean. In the upper two layers, the changes are mainly caused by the enhanced mixing, as warm and salty water sinks and cold and fresh water rises; whereas in the deep layer, the enhancement of the deep overturning circulation accounts for the cold and fresh changes in the deep ocean.

  13. On optimization of data assimilation in the HBM -circulation model

    OpenAIRE

    VÀhÀ-Piikkiö, Olga

    2015-01-01

    The purpose of this study is to develop a method for optimizing the data assimilation system of the HIROMB-BOOS -model at the Finnish Meteorological Institute by finding an optimal time interval and an optimal grid for the data assimilation. This is needed to balance the extra time the data assimilation adds to the runtime of the model and the improved accuracy it provides. Data assimilation is the process of combining observations with a numerical model to improve the accuracy of the mod...

  14. Prediction of cloud droplet number in a general circulation model

    Energy Technology Data Exchange (ETDEWEB)

    Ghan, S.J.; Leung, L.R. [Pacific Northwest National Lab., Richland, WA (United States)

    1996-04-01

    We have applied the Colorado State University Regional Atmospheric Modeling System (RAMS) bulk cloud microphysics parameterization to the treatment of stratiform clouds in the National Center for Atmospheric Research Community Climate Model (CCM2). The RAMS predicts mass concentrations of cloud water, cloud ice, rain and snow, and number concnetration of ice. We have introduced the droplet number conservation equation to predict droplet number and it`s dependence on aerosols.

  15. Modeling Residual Circulation and Stratification in Oujiang River Estuary

    Institute of Scientific and Technical Information of China (English)

    LIN Wei-bo; WANG Yi-gang; RUAN Xiao-hong; XU Qun

    2012-01-01

    A 3D,time-dependent,baroclinic,hydrodynamic and salinity model was implemented and applied to the Oujiang River estuarine system in the East China Sea.The model was driven by the forcing of tidal elevations along the open boundaries and freshwater inflows from the Oujiang River.The bottom friction coefficient and vertical eddy viscosity were adjusted to complete model calibration and verification in simulations.It is demonstrated that the model is capable of reproducing observed temporal variability in the water surface elevation and longitudinal velocity,presenting skill coefficient higher than 0.82.This model was then used to investigate the influence of freshwater discharge on residual current and salinity intrusion under different freshwater inflow conditions in the Oujiang River estuary.The model results reveal that the river channel presents a two-layer structure with flood currents near the bottom and ebb currents at the top layer in the region of seawater influenced on north shore under high river flow condition.The river discharge is a major factor affecting the salinity stratification in the estuarine system.The water exchange is mainly driven by the tidal forcing at the estuary mouth,except under high river flow conditions when the freshwater extends its influence from the river's head to its mouth.

  16. Global Coupled Ocean-Atmosphere General Circulation Models in LASG/IAP

    Institute of Scientific and Technical Information of China (English)

    俞永强; 张学洪; 郭裕福

    2004-01-01

    Coupled ocean-atmospheric general circulation models are the only tools to quantitatively simulate the climate system. Since the end of the 1980s, a group of scientists in the State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics (LASG), Institute of Atmospheric Physics (IAP), Chinese Academy of Sciences (CAS), have been working to develop a global OGCM and a global coupled ocean-atmosphere general circulation model (CGCM). From the original flux anomalycoupling model developed in the beginning of the 1990s to the latest directly-coupling model, LASG scientists have developed four global coupled GCMs. This study summarizes the development history of these models and describes the third and fourth coupled GCMs and selected applications. Strengths and weaknesses of these models are highlighted.

  17. A global mean ocean circulation estimation using goce gravity models - the DTU12MDT mean dynamic topography model

    DEFF Research Database (Denmark)

    Knudsen, Per; Andersen, Ole Baltazar

    2012-01-01

    The Gravity and Ocean Circulation Experiment - GOCE satellite mission measure the Earth gravity field with unprecedented accuracy leading to substantial improvements in the modelling of the ocean circulation and transport. In this study of the performance of GOCE, a newer gravity model have been...... combined with the DTU10MSS mean sea surface model to construct a global mean dynamic topography model named DTU10MDT. The results of preliminary analyses using preliminary GOCE gravity models clearly demonstrated the potential of GOCE mission. Both the resolution and the estimation of the surface currents...... have been improved significantly compared to results obtained using pre-GOCE gravity field models. The results of this study show that geostrophic surface currents associated with the mean circulation have been further improved and that currents having speeds down to 5 cm/s have been recovered....

  18. Asymptotic solutions of the axisymmetric moist Hadley circulation in a model with two vertical modes

    Energy Technology Data Exchange (ETDEWEB)

    Burns, Samuel P. [Columbia University, Department of Applied Physics and Applied Mathematics, New York, NY (United States); New York University, Courant Institute, New York, NY (United States); Sobel, Adam H.; Polvani, Lorenzo M. [Columbia University, Department of Applied Physics and Applied Mathematics, New York, NY (United States)

    2006-11-15

    A simplified model of the moist axisymmetric Hadley circulation is examined in the asymptotic limit in which surface drag is strong and the meridional wind is weak compared to the zonal wind. Our model consists of the quasi-equilibrium tropical circulation model (QTCM) equations on an axisymmetric aquaplanet equatorial beta-plane. This model includes two vertical momentum modes, one baroclinic and one barotropic. Prior studies use either continuous stratification, or a shallow water system best viewed as representing the upper troposphere. The analysis here focuses on the interaction of the baroclinic and barotropic modes, and the way in which this interaction allows the constraints on the circulation known from the fully stratified case to be satisfied in an approximate way. The dry equations, with temperature forced by Newtonian relaxation towards a prescribed radiative equilibrium, are solved first. To leading order, the resulting circulation has a zonal wind profile corresponding to uniform angular momentum at a level near the tropopause, and zero zonal surface wind, owing to the cancelation of the barotropic and baroclinic modes there. The weak surface winds are calculated from the first-order corrections. The broad features of these solutions are similar to those obtained in previous studies of the dry Hadley circulation. The moist equations are solved next, with a fixed sea surface temperature at the lower boundary and simple parameterizations of surface fluxes, deep convection, and radiative transfer. The solutions yield the structure of the barotropic and baroclinic winds, as well as the temperature and moisture fields. In addition, we derive expressions for the width and strength of the equatorial precipitating region (ITCZ) and the width of the entire Hadley circulation. The ITCZ width is on the order of a few degrees in the absence of any horizontal diffusion and is relatively insensitive to parameter variations. (orig.)

  19. Modelling of hydrodynamic circulation in Benoa Bay, Bali

    DEFF Research Database (Denmark)

    Ningsih, Nining Sari; Muchamad, Al Azhar

    2013-01-01

    A simulation of water level, velocity, salinity, and temperature in the Bay of Benoa has been carried out using a three-dimensional hydrodynamic Estuarine and Coastal Ocean Model incorporating a main characteristic of southward transport of the Indonesian throughflow at the offshore area of the bay....... In other respects, two types of boundary conditions have been tested: (1) specifying elevation at all boundaries; and (2) implementing a combination of elevation and velocity at the boundaries. Performance of the model results has been quantified in terms of mean absolute errors, root-mean square errors...

  20. Multiscale modeling of blood flow: from single cells to blood rheology.

    Science.gov (United States)

    Fedosov, Dmitry A; Noguchi, Hiroshi; Gompper, Gerhard

    2014-04-01

    Mesoscale simulations of blood flow, where the red blood cells are described as deformable closed shells with a membrane characterized by bending rigidity and stretching elasticity, have made much progress in recent years to predict the flow behavior of blood cells and other components in various flows. To numerically investigate blood flow and blood-related processes in complex geometries, a highly efficient simulation technique for the plasma and solutes is essential. In this review, we focus on the behavior of single and several cells in shear and microcapillary flows, the shear-thinning behavior of blood and its relation to the blood cell structure and interactions, margination of white blood cells and platelets, and modeling hematologic diseases and disorders. Comparisons of the simulation predictions with existing experimental results are made whenever possible, and generally very satisfactory agreement is obtained.

  1. Evaluation of a stratiform cloud parameterization for general circulation models

    Energy Technology Data Exchange (ETDEWEB)

    Ghan, S.J.; Leung, L.R. [Pacific Northwest National Lab., Richland, WA (United States); McCaa, J. [Univ. of Washington, Seattle, WA (United States)

    1996-04-01

    To evaluate the relative importance of horizontal advection of cloud versus cloud formation within the grid cell of a single column model (SCM), we have performed a series of simulations with our SCM driven by a fixed vertical velocity and various rates of horizontal advection.

  2. A Nd Isotopic Composition Modeling Approach of the Oceanic Thermohaline Circulation Change During LGM

    Science.gov (United States)

    Arsouze, T.; Dutay, J.; Lacan, F.; Jeandel, C.; Alkama, R.; Kageyama, M.; Piotrowski, A.

    2006-12-01

    The role of thermohaline circulation in climate change has been a matter of debate for a long time. Proxies of past ocean circulation such as δ13C or 231Pa/230Th suggest a relationship between North Atlantic Deep Water (NADW) strength and rapid climate change. Neodymium isotopic composition (Nd IC) is a quasi conservative geochemical tracer of water masses in the ocean interior and thus can be used as a proxy for NADW. Seawater Nd IC being recorded in marine sediments, this proxy is used to infer paleo-circulations on various time scales. Recent studies of Nd IC records, in the ferromanganese oxide components of a South Atlantic core, confirm the close relation between thermohaline circulation and North Atlantic climate changes through the last deglaciation (Piotrowski et al., 2004). Our purpose here is to model the Nd IC during the LGM and the Holocene with the Ocean Global Circulation Model NEMO, in the ORCA2 (2°) configuration. The explicit simulation of this proxy in the model allows to investigate and quantify the circulation change that corresponds to the Nd isotopic composition variation recorded in the sediments. We consider that the main source of Nd into the ocean is the interaction between water masses and continental margins (Boundary Exchange process; (Lacan and Jeandel, 2005). Boundary exchange is parameterized using a relaxing term (Arsouze et al., 2006). Simulated Nd IC distributions are evaluated by comparison with available records for the LGM and Holocene. References: Arsouze, T., Dutay, J.-C., Lacan, F. and Jeandel, C., 2006. Modeling the neodymium isotopic composition with a global ocean circulation model Chemical Geology, in press. Lacan, F. and Jeandel, C., 2005. Neodymium isotopes as a new tool for quantifying exchange fluxes at the continent - ocean interface. Earth and Planetary Science Letters, 232(3-4): 245-257. Piotrowski, A.M., Goldstein, S.L., Hemming, S.R. and Fairbanks, R.G., 2004. Intensification and variability of ocean

  3. North Atlantic thermohaline circulation predictability in a coupled ocean-atmosphere model

    CERN Document Server

    Griffies, S M; Griffies, Stephen M.; Bryan, Kirk

    1995-01-01

    Predictability of the North Atlantic thermohaline circulation (THC) variability as simulated in the GFDL coupled ocean-atmosphere general circulation model is established for a set of ensemble experiments. The ensembles consist of identical oceanic initial conditions underneath a model atmosphere chosen randomly from the model climatology. This experimental design is based on the separation in time scales present in the model which motivates the assumption that the predictability deduced from these ensembles provides an upper limit to the model's THC predictability. The climatology is taken from a multi-century model integration whose THC variability has power concentrated at the 40-60 year time scale. A linear stochastic perspective is shown to be generally consistent with the ensemble statistics. The linear theory suggests a natural measure of ensemble predictability as the time at which the ensemble variance becomes a subjectively defined fraction (0.5 used here) of the climatological variance. It is furth...

  4. A statistical assessment of tropical cyclone activity in atmospheric general circulation models

    OpenAIRE

    Suzana J. Camargo; Barnston, Anthony G; Zebiak, Stephen E.

    2005-01-01

    The properties of tropical cyclones in three low-resolution atmospheric general circulation models (AGCMs) in seven ocean basins are discussed. The models are forced by prescribed, observed sea surface temperatures over a period of 40 yr, and their simulations of tropical cyclone activity are compared with observations. The model cyclone characteristics considered include genesis position, number of cyclones per year, seasonality, accumulated cyclone energy, track locations, and number of sto...

  5. Exploring the Venus global super-rotation using a comprehensive General Circulation Model

    CERN Document Server

    Mendonça, João M

    2016-01-01

    The atmospheric circulation in Venus is well known to exhibit strong super-rotation. However, the atmospheric mechanisms responsible for the formation of this super-rotation are still not fully understood. In this work, we developed a new Venus general circulation model to study the most likely mechanisms driving the atmosphere to the current observed circulation. Our model includes a new radiative transfer, convection and suitably adapted boundary layer schemes and a dynamical core that takes into account the dependence of the heat capacity at constant pressure with temperature. The new Venus model is able to simulate a super-rotation phenomenon in the cloud region quantitatively similar to the one observed. The mechanisms maintaining the strong winds in the cloud region were found in the model results to be a combination of zonal mean circulation, thermal tides and transient waves. In this process, the semi-diurnal tide excited in the upper clouds has a key contribution in transporting axial angular momentu...

  6. Symmetry Reductions of a 1.5-Layer Ocean Circulation Model

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The (2+1)-dimensional nonlinear 1.5-layer ocean circulation model without external wind stress forcing is analyzed by using the classical Lie group approach. Some Lie point symmetries and their corresponding two-dimensional reduction equations are obtained.

  7. The response of Mediterranean thermohaline circulation to climate change: a minimal model

    NARCIS (Netherlands)

    Meijer, P.Th.; Dijkstra, H.A.

    2009-01-01

    Physics-based understanding of the effects of paleoclimate and paleogeography on the thermohaline circulation of the Mediterranean Sea requires an ocean model capable of long integrations and involving a minimum of assumptions about the atmospheric forcing. Here we examine the sensitivity of the dee

  8. Improved short-term variability in the thermosphere-ionosphere-mesosphere-electrodynamics general circulation model

    NARCIS (Netherlands)

    Häusler, K.; Hagan, M.E.; Baumgaertner, A.J.G.; Maute, A.; Lu, G.; Doornbos, E.N.; Bruinsma, S.; Forbes, J.M.; Gasperini, F.

    2014-01-01

    We report on a new source of tidal variability in the National Center for Atmospheric Research thermosphere-ionosphere-mesosphere-electrodynamics general circulation model (TIME-GCM). Lower boundary forcing of the TIME-GCM for a simulation of November–December 2009 based on 3-hourly Modern-Era Retro

  9. Simulation of the Low-Level-Jet by general circulation models

    Energy Technology Data Exchange (ETDEWEB)

    Ghan, S.J. [Pacific Northwest National Lab., Richland, WA (United States)

    1996-04-01

    To what degree is the low-level jet climatology and it`s impact on clouds and precipitation being captured by current general circulation models? It is hypothesised that a need for a pramaterization exists. This paper describes this parameterization need.

  10. Model-free adaptive control of supercritical circulating fluidized-bed boilers

    Science.gov (United States)

    Cheng, George Shu-Xing; Mulkey, Steven L

    2014-12-16

    A novel 3-Input-3-Output (3.times.3) Fuel-Air Ratio Model-Free Adaptive (MFA) controller is introduced, which can effectively control key process variables including Bed Temperature, Excess O2, and Furnace Negative Pressure of combustion processes of advanced boilers. A novel 7-input-7-output (7.times.7) MFA control system is also described for controlling a combined 3-Input-3-Output (3.times.3) process of Boiler-Turbine-Generator (BTG) units and a 5.times.5 CFB combustion process of advanced boilers. Those boilers include Circulating Fluidized-Bed (CFB) Boilers and Once-Through Supercritical Circulating Fluidized-Bed (OTSC CFB) Boilers.

  11. Impact of an improved shortwave radiation scheme in the MAECHAM5 General Circulation Model

    Directory of Open Access Journals (Sweden)

    J. J. Morcrette

    2007-05-01

    Full Text Available In order to improve the representation of ozone absorption in the stratosphere of the MAECHAM5 general circulation model, the spectral resolution of the shortwave radiation parameterization used in the model has been increased from 4 to 6 bands. Two 20-years simulations with the general circulation model have been performed, one with the standard and the other with the newly introduced parameterization respectively, to evaluate the temperature and dynamical changes arising from the two different representations of the shortwave radiative transfer. In the simulation with the increased spectral resolution in the radiation parameterization, a significant warming of almost the entire model domain is reported. At the summer stratopause the temperature increase is about 6 K and alleviates the cold bias present in the model when the standard radiation scheme is used. These general circulation model results are consistent both with previous validation of the radiation scheme and with the offline clear-sky comparison performed in the current work with a discrete ordinate 4 stream scattering line by line radiative transfer model. The offline validation shows a substantial reduction of the daily averaged shortwave heating rate bias (1–2 K/day cooling that occurs for the standard radiation parameterization in the upper stratosphere, present under a range of atmospheric conditions. Therefore, the 6 band shortwave radiation parameterization is considered to be better suited for the representation of the ozone absorption in the stratosphere than the 4 band parameterization. Concerning the dynamical response in the general circulation model, it is found that the reported warming at the summer stratopause induces stronger zonal mean zonal winds in the middle atmosphere. These stronger zonal mean zonal winds thereafter appear to produce a dynamical feedback that results in a dynamical warming (cooling of the polar winter (summer mesosphere, caused by an

  12. Comparing a quasi-3D to a full 3D nearshore circulation model: SHORECIRC and ROMS

    Science.gov (United States)

    Haas, K.A.; Warner, J.C.

    2009-01-01

    Predictions of nearshore and surf zone processes are important for determining coastal circulation, impacts of storms, navigation, and recreational safety. Numerical modeling of these systems facilitates advancements in our understanding of coastal changes and can provide predictive capabilities for resource managers. There exists many nearshore coastal circulation models, however they are mostly limited or typically only applied as depth integrated models. SHORECIRC is an established surf zone circulation model that is quasi-3D to allow the effect of the variability in the vertical structure of the currents while maintaining the computational advantage of a 2DH model. Here we compare SHORECIRC to ROMS, a fully 3D ocean circulation model which now includes a three dimensional formulation for the wave-driven flows. We compare the models with three different test applications for: (i) spectral waves approaching a plane beach with an oblique angle of incidence; (ii) monochromatic waves driving longshore currents in a laboratory basin; and (iii) monochromatic waves on a barred beach with rip channels in a laboratory basin. Results identify that the models are very similar for the depth integrated flows and qualitatively consistent for the vertically varying components. The differences are primarily the result of the vertically varying radiation stress utilized by ROMS and the utilization of long wave theory for the radiation stress formulation in vertical varying momentum balance by SHORECIRC. The quasi-3D model is faster, however the applicability of the fully 3D model allows it to extend over a broader range of processes, temporal, and spatial scales. ?? 2008 Elsevier Ltd.

  13. Mathematical Model of Extrinsic Blood Coagulation Cascade Dynamic System

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The blood coagulation system is very important to life. This paper presents a mathematical blood coagulation model for the extrinsic pathway. This model simulates clotting factor VIII, which plays an important role in the coagulation mechanism. The mathematical model is used to study the equilibrium stability, orbit structure, attractors and global stability behavior, with conclusions in accordance with the physiological phenomena. Moreover, the results provide information about blood related illnesses, which can be used for further study of the coagulation mechanism.

  14. Surface circulation at the Strait of Gibraltar: A combined HF radar and high resolution model study

    Science.gov (United States)

    Soto-Navarro, Javier; Lorente, Pablo; Álvarez Fanjul, Enrique; Carlos Sánchez-Garrido, Jose; García-Lafuente, Jesús

    2016-03-01

    Observations from a high frequency radar system and outputs from a high resolution operational ocean model working at the Strait of Gibraltar have been analyzed and compared during the period February 2013 to September 2014 in order to evaluate their capability to resolve the surface circulation of the region. The description of the mean circulation patterns has been statistically assessed, showing good agreement, particularly in the central region of the strait corresponding with the Atlantic Jet (AJ) stream, although some short scale features are not reproduced by the model. In the frequency domain very high concordance is observed. Tidal maps of diurnal and semidiurnal constituents are in good agreement with previous observations. The analysis of the model and radar response to the wind forcing reveals that the low resolution of the model wind-forcing field and its deeper superficial level smoothes the wind effect on the simulated currents. The first three EOF modes account for the 86% of model and radar variances. The coincidence between the observed and simulated patterns is very significant for the first two modes, which account for the mean velocity field and the latitudinal shifting of the AJ consequence of the flow-topography interaction. The third mode captures the wind-induced circulation, and greater discrepancies are found in this case. Results underline the complementary character of both systems: radar observations improve the model description, resolving short scale processes, while the model completes the radar information when the time or spatial coverage is poorer.

  15. Modeling Study of a New Circulating Fluidized Bi—Bed Boiler Combustion System

    Institute of Scientific and Technical Information of China (English)

    ZhaoJian; SuoYisheng; 等

    1999-01-01

    This paper presents a set of general dynamic mathematical models for the combustion system of a circulating fluidized bi-bed boiler,The models fully consider the flow.combustion and heat transfer characteristics,and describe the physical and chemical processes inside the bi-bed,including the gassolid flow.multiple particles combustion,gas chemical reactions,heat transfer and pressure balances.etc.

  16. A wind-driven circulation model of the Tyrrhenian Sea area

    Science.gov (United States)

    Pierini, S.; Simioli, A.

    1998-12-01

    The wind-driven component of the circulation in the Tyrrhenian Sea area was analyzed by means of a free-surface, barotropic primitive equation model implemented in the whole Mediterranean Sea. The `National Meteorological Center' (NMC) wind data covering the period 1980-1988 were used to force the model. Both the seasonal and the high frequency variability were studied. For the first case, a perpetual wind forcing was constructed by instantaneously averaging the wind stresses over the 9 years, and the response was Fourier filtered in order to get rid of the residual rapid fluctuations. The daily variability was then produced for the test years 1981 and 1987 by making use of the instantaneous forcing. The main features of the wind-driven climatological Tyrrhenian circulation known from data and general circulation modelling were found to be reproduced by this process model. The winter cyclonic circulation induced by the strong positive wind vorticity input evolved into a much weaker, partially reversed circulation in summer months. A mainly northward flux through the strait of Corsica and a horizontally sheared current in the strait of Sicily were found. The rapid fluctuations that the wind was able to induce in the ocean were then studied. The instantaneous currents were found to be up to 10 times larger than the corresponding climatological ones, with episodes of reversal over a period of few days. The experimental evidence of the existence of these rapid wind-driven fluctuations is discussed. The analysis of the daily variability provides a realistic picture of the character of the wind-driven circulation in the Tyrrhenian Sea that differs considerably from the classical seasonal dynamics. As an indicator of the Tyrrhenian Sea dynamics, the mass transport through the strait of Corsica was evaluated for the year 1987 and compared with available experimental data. As a result, the low-passed wind-driven transport reflects the seasonal trend and accounts for 15

  17. Ross ice shelf cavity circulation, residence time, and melting: Results from a model of oceanic chlorofluorocarbons

    Science.gov (United States)

    Reddy, Tasha E.; Holland, David M.; Arrigo, Kevin R.

    2010-04-01

    Despite their harmful effects in the upper atmosphere, anthropogenic chlorofluorocarbons dissolved in seawater are extremely useful for studying ocean circulation and ventilation, particularly in remote locations. Because they behave as a passive tracer in seawater, and their atmospheric concentrations are well-mixed, well-known, and have changed over time, they are ideal for gaining insight into the oceanographic characteristics of the isolated cavities found under Antarctic ice shelves, where direct observations are difficult to obtain. Here we present results from a modeling study of air-sea chlorofluorocarbon exchange and ocean circulation in the Ross Sea, Antarctica. We compare our model estimates of oceanic CFC-12 concentrations along an ice shelf edge transect to field data collected during three cruises spanning 16 yr. Our model produces chlorofluorocarbon concentrations that are quite similar to those measured in the field, both in magnitude and distribution, showing high values near the surface, decreasing with depth, and increasing over time. After validating modeled circulation and air-sea gas exchange through comparison of modeled temperature, salinity, and chlorofluorocarbons with field data, we estimate that the residence time of water in the Ross Ice Shelf cavity is approximately 2.2 yr and that basal melt rates for the ice shelf average 10 cm yr -1. The model predicts a seasonal signature to basal melting, with highest melt rates in the spring and also the fall.

  18. The experiment of monthly mean circulation prediction using the analogy-dynamical model

    Institute of Scientific and Technical Information of China (English)

    BAO Ming; NI Yunqi; CHOU Jifan

    2004-01-01

    Based on the past related research work, a new analogy-dynamical monthly prediction model is established with the operational dynamic extended-range forecast model T63L16 (hereafter T63) as a dynamic kernel. The monthly mean circulation prediction with T63 is considered as a control experiment, and the prediction with the analogy-dynamical model as a contrast one. It is found that the analogy-dynamical model has more precise forecast skill than the T63 model through monthly mean numerical prediction experiment.

  19. Exploring the Venus global super-rotation using a comprehensive general circulation model

    Science.gov (United States)

    Mendonça, J. M.; Read, P. L.

    2016-12-01

    The atmospheric circulation in Venus is well known to exhibit strong super-rotation. However, the atmospheric mechanisms responsible for the formation of this super-rotation are still not fully understood. In this work, we developed a new Venus general circulation model to study the most likely mechanisms driving the atmosphere to the current observed circulation. Our model includes a new radiative transfer, convection and suitably adapted boundary layer schemes and a dynamical core that takes into account the dependence of the heat capacity at constant pressure with temperature. The new Venus model is able to simulate a super-rotation phenomenon in the cloud region quantitatively similar to the one observed. The mechanisms maintaining the strong winds in the cloud region were found in the model results to be a combination of zonal mean circulation, thermal tides and transient waves. In this process, the semi-diurnal tide excited in the upper clouds has a key contribution in transporting axial angular momentum mainly from the upper atmosphere towards the cloud region. The magnitude of the super-rotation in the cloud region is sensitive to various radiative parameters such as the amount of solar radiative energy absorbed by the surface, which controls the static stability near the surface. In this work, we also discuss the main difficulties in representing the flow below the cloud base in Venus atmospheric models. Our new radiative scheme is more suitable for 3D Venus climate models than those used in previous work due to its easy adaptability to different atmospheric conditions. This flexibility of the model was crucial to explore the uncertainties in the lower atmospheric conditions and may also be used in the future to explore, for example, dynamical-radiative-microphysical feedbacks.

  20. Cloud-radiative effects on implied oceanic energy transport as simulated by atmospheric general circulation models

    Science.gov (United States)

    Gleckler, P. J.; Randall, D. A.; Boer, G.; Colman, R.; Dix, M.; Galin, V.; Helfand, M.; Kiehl, J.; Kitoh, A.; Lau, W.

    1995-01-01

    This paper summarizes the ocean surface net energy flux simulated by fifteen atmospheric general circulation models constrained by realistically-varying sea surface temperatures and sea ice as part of the Atmospheric Model Intercomparison Project. In general, the simulated energy fluxes are within the very large observational uncertainties. However, the annual mean oceanic meridional heat transport that would be required to balance the simulated surface fluxes is shown to be critically sensitive to the radiative effects of clouds, to the extent that even the sign of the Southern Hemisphere ocean heat transport can be affected by the errors in simulated cloud-radiation interactions. It is suggested that improved treatment of cloud radiative effects should help in the development of coupled atmosphere-ocean general circulation models.

  1. A method to permanently collapse the Atlantic Meridional Overturning Circulation in climate models

    CERN Document Server

    Cimatoribus, Andrea A; Drijfhout, Sybren S; Dijkstra, Henk A

    2011-01-01

    The sensitivity of the Atlantic Meridional Overturning Circulation (AMOC) to changes in basin integrated net evaporation is highly dependent on the zonal salinity contrast at the southern border of the Atlantic. Biases in the freshwater budget strongly affect the stability of the AMOC. The impact of these biases is investigated in a coupled ocean-atmosphere model by adding local anomaly patterns to the freshwater fluxes at the surface. These anomalies impact the freshwater and salt transport by the different components of the ocean circulation, in particular the basin-scale salt-advection feedback, completely changing the response of the AMOC to arbitrary perturbations. It is found that an appropriate dipole anomaly pattern at the southern border of the Atlantic Ocean can collapse the AMOC entirely even without a further hosing. Based on these results, a method is proposed for permanently collapsing the AMOC in climate models and to systematically test the existence of multiple equilibria in these models.

  2. Statistical downscaling of general circulation model output: A comparison of methods

    Science.gov (United States)

    Wilby, R. L.; Wigley, T. M. L.; Conway, D.; Jones, P. D.; Hewitson, B. C.; Main, J.; Wilks, D. S.

    1998-11-01

    A range of different statistical downscaling models was calibrated using both observed and general circulation model (GCM) generated daily precipitation time series and intercompared. The GCM used was the U.K. Meteorological Office, Hadley Centre's coupled ocean/atmosphere model (HadCM2) forced by combined CO2 and sulfate aerosol changes. Climate model results for 1980-1999 (present) and 2080-2099 (future) were used, for six regions across the United States. The downscaling methods compared were different weather generator techniques (the standard "WGEN" method, and a method based on spell-length durations), two different methods using grid point vorticity data as an atmospheric predictor variable (B-Circ and C-Circ), and two variations of an artificial neural network (ANN) transfer function technique using circulation data and circulation plus temperature data as predictor variables. Comparisons of results were facilitated by using standard sets of observed and GCM-derived predictor variables and by using a standard suite of diagnostic statistics. Significant differences in the level of skill were found among the downscaling methods. The weather generation techniques, which are able to fit a number of daily precipitation statistics exactly, yielded the smallest differences between observed and simulated daily precipitation. The ANN methods performed poorly because of a failure to simulate wet-day occurrence statistics adequately. Changes in precipitation between the present and future scenarios produced by the statistical downscaling methods were generally smaller than those produced directly by the GCM. Changes in daily precipitation produced by the GCM between 1980-1999 and 2080-2099 were therefore judged not to be due primarily to changes in atmospheric circulation. In the light of these results and detailed model comparisons, suggestions for future research and model refinements are presented.

  3. [The role of nitric oxide in regulation of the erythrocyte system state in rat offspring with chronic disturbance of uteroplacental blood circulation].

    Science.gov (United States)

    Nazarov, S B; Ivanova, A S; Novikov, A A

    2012-01-01

    The effect of exogenous nitric oxide donor deponit-10 (nitroglycerin) on red cell indices in the offspring of rats with experimental disturbances of uteroplacental circulation has been investigated. It is established that fetal hypoxia facilitates the mobilization of functional reserves of the red cell system in the prenatal and early days of postnatal life of offspring in white rats, which is manifested by the growing process of erythropoiesis. Hyperfunction of the erythrocyte system in the first lifedays of pups leads eventually to a depletion of its functional capacities. The administration of an exogenous nitric oxide donor on the background of damaged uteroplacental circulation prevents the depletion and disruption of the functional reserves of the blood red cell system.

  4. Ultra High-Resolution In vivo Computed Tomography Imaging of Mouse Cerebrovasculature Using a Long Circulating Blood Pool Contrast Agent.

    Science.gov (United States)

    Starosolski, Zbigniew; Villamizar, Carlos A; Rendon, David; Paldino, Michael J; Milewicz, Dianna M; Ghaghada, Ketan B; Annapragada, Ananth V

    2015-05-18

    Abnormalities in the cerebrovascular system play a central role in many neurologic diseases. The on-going expansion of rodent models of human cerebrovascular diseases and the need to use these models to understand disease progression and treatment has amplified the need for reproducible non-invasive imaging methods for high-resolution visualization of the complete cerebral vasculature. In this study, we present methods for in vivo high-resolution (19 μm isotropic) computed tomography imaging of complete mouse brain vasculature. This technique enabled 3D visualization of large cerebrovascular networks, including the Circle of Willis. Blood vessels as small as 40 μm were clearly delineated. ACTA2 mutations in humans cause cerebrovascular defects, including abnormally straightened arteries and a moyamoya-like arteriopathy characterized by bilateral narrowing of the internal carotid artery and stenosis of many large arteries. In vivo imaging studies performed in a mouse model of Acta2 mutations demonstrated the utility of this method for studying vascular morphometric changes that are practically impossible to identify using current histological methods. Specifically, the technique demonstrated changes in the width of the Circle of Willis, straightening of cerebral arteries and arterial stenoses. We believe the use of imaging methods described here will contribute substantially to the study of rodent cerebrovasculature.

  5. Stealth CD44-targeted hyaluronic acid supramolecular nanoassemblies for doxorubicin delivery: probing the effect of uncovalent pegylation degree on cellular uptake and blood long circulation.

    Science.gov (United States)

    Han, Xiaopeng; Li, Zhenbao; Sun, Jin; Luo, Cong; Li, Lin; Liu, Yuhai; Du, Yuqian; Qiu, Shuhong; Ai, Xiaoyu; Wu, Chunnuan; Lian, He; He, Zhonggui

    2015-01-10

    Stealth active targeting nanoparticles (NPs) usually include two types of ligand sites: ligand anchored on distal ends of the polyethylene glycol (PEG) and ligand buried under pegylated layer. The latter typical case is hyaluronic acid (HA)-based NPs; however, there is little information available for the latter NPs about effect of the optimal density of surface PEG coating on the blood circulation time, cellular uptake and in vivo anticancer activity. Thus, in this study, in order to optimize the anticancer effects of HA-based NPs, we focus on how uncovalent pegylation degree modulates blood circulation time and cellular uptake of HA-based NPs. We firstly designed a new double-hydrophilic copolymer by conjugating HP-β-cyclodextrin with HA, and this carrier was further pegylated with adamantyl-peg (ADA-PEG) to form inclusion complex HA-HPCD/ADA-PEG, termed as HCPs. The supramolecular nanoassemblies were fabricated by host-guest and polar interactions between HCPs and doxorubicin (Dox), with vitamin E succinate (VES) being a nanobridge. Despite the active recognition between HA and CD44 receptor, the cellular uptake and targeting efficiency of HA-NPs decreased with the increasing peg density, demonstrating HA was partly buried by high density peg coating. However, the high density of peg coating was beneficial to long circulation time, tumor biodistribution and anticancer activity in vivo. NPs with 5% peg coating had the optimal cellular targeting efficiency in vitro and anticancer effects in vivo. The findings suggest that balancing long circulation property and cellular uptake is important to achieve the optimal antitumor efficacy for pegylated HA-based NPs, and that PEG coating densities cannot be extended beyond a certain density for shielding effect without compromising the efficacy of hyaluronic acid targeted delivery.

  6. Causes and impacts of changes in the stratospheric meridional circulation in a chemistry-climate model

    Energy Technology Data Exchange (ETDEWEB)

    Garny, Hella

    2011-05-13

    The stratospheric meridional circulation is projected to be subject to changes due to enhanced greenhouse-gas concentrations in the atmosphere. This study aims to diagnose and explain long-term changes in the stratospheric meridional circulation using the chemistry-climate model E39CA. The diagnosed strengthening of the circulation is found to be driven by increases in tropical sea surface temperatures which lead to a strengthening and upward shift of the subtropical jets. This enables enhanced vertical propagation of large scale waves into the lower stratosphere, and therefore stronger local wave forcing of the meridional circulation in the tropical lower stratosphere. The impact of changes in transport on the ozone layer is analysed using a newly developed method that allows the separation of the effects of transport and chemistry changes on ozone. It is found that future changes of mean stratospheric ozone concentrations are largely determined by changes in chemistry, while changes in transport of ozone play a minor role. (orig.)

  7. Two regimes of the Arctic's circulation from ocean models with ice and contaminants.

    Science.gov (United States)

    Proshutinsky, A Y; Johnson, M

    2001-01-01

    A two-dimensional barotropic, coupled, ocean-ice model with a space resolution of 55.5 km and driven by atmospheric forces, river run-off, and sea-level slope between the Pacific and the Arctic Oceans, has been used to simulate the vertically averaged currents and ice drift in the Arctic Ocean. Results from 43 years of numerical simulations of water and ice motions demonstrate that two wind-driven circulation regimes are possible in the Arctic, a cyclonic and an anti-cyclonic circulation. These two regimes appear to alternate at 5-7 year intervals with the 10-15 year period. It is important to pollution studies to understand which circulation regime prevails at any time. It is anticipated that 1995 is a year with a cyclonic regime, and during this cyclonic phase and possibly during past cyclonic regimes as well, pollutants may reach the Alaskan shelf. The regime shifts demonstrated in this paper are fundamentally important to understanding the Arctic's general circulation and particularly important for estimating pollution transport.

  8. Response of the equatorial Pacific to chlorophyll pigment in a mixed layer isopycnal ocean general circulation model

    Digital Repository Service at National Institute of Oceanography (India)

    Nakamoto, S.; PrasannaKumar, S.; Oberhuber, J.M.; Ishizaka, J.; Muneyama, K.; Frouin, R.

    The influence of phytoplankton on the upper ocean dynamics and thermodynamics in the equatorial Pacific is investigated using an isopycnal ocean general circulation model (OPYC) coupled with a mixed layer model and remotely sensed chlorophyll...

  9. 活血化瘀法在老年病中的应用%Promoting Blood Circulation Method Apply In Geriatrics

    Institute of Scientific and Technical Information of China (English)

    何慧珍

    2011-01-01

    From the continued study of the physiological and pathological changes in the elderly and understanding of the relationship between human physiological and pathological changes in qi and blood, it finds that Stasis is the most important influencing factor in the development of Geriatrics, and combining the study of the nature of modem stasis and the mechanism of promoting blood circulation method.Promoting blood circulation method was considered to have a significant effect in elderly common diseases, frequentlyoccurring disease, and complicated cases.%从对老年人生理病理变化的不断研究及对气血与人体生理病理变化关系的认识出发,阐明血瘀在影响老年病发生发展的诸多因素中占有主导地位,并结合现代对血瘀本质及活血化瘀法作用机制的研究,探讨活血化瘀法在老年常见病多发病以及老年疑难杂病中的应用.

  10. An analytical and experimental investigation of natural circulation transients in a model pressurized water reactor

    Energy Technology Data Exchange (ETDEWEB)

    Massoud, M

    1987-01-01

    Natural Circulation phenomena in a simulated PWR was investigated experimentally and analytically. The experimental investigation included determination of system characteristics as well as system response to the imposed transient under symmetric and asymmetric operations. System characteristics were used to obtain correlation for heat transfer coefficient in heat exchangers, system flow resistance, and system buoyancy heat. Asymmetric transients were imposed to study flow oscillation and possible instability. The analytical investigation encompassed development of mathematical model for single-phase, steady-state and transient natural circulation as well as modification of existing model for two-phase flow analysis of phenomena such as small break LOCA, high pressure coolant injection and pump coast down. The developed mathematical model for single-phase analysis was computer coded to simulate the imposed transients. The computer program, entitled ''Symmetric and Asymmetric Analysis of Single-Phase Flow (SAS),'' were employed to simulate the imposed transients. It closely emulated the system behavior throughout the transient and subsequent steady-state. Modifications for two-phase flow analysis included addition of models for once-through steam generator and electric heater rods. Both programs are faster than real time. Off-line, they can be used for prediction and training applications while on-line they serve for simulation and signal validation. The programs can also be used to determine the sensitivity of natural circulation behavior to variation of inputs such as secondary distribution and power transients.

  11. Blood Volume, Plasma Volume and Circulation Time in a High-Energy-Demand Teleost, the Yellowfin Tuna (Thunnus Albacares)

    DEFF Research Database (Denmark)

    Brill, R.W.; Cousins, K.L.; Jones, D.R.

    1998-01-01

    tuna, circulation time is approximately 0.4 min (47 ml kg-1/115 ml min-1 kg- 1) compared with 1.3 min (46 ml kg-1/35 ml min-1 kg-1) in yellowtail (Seriola quinqueradiata) and 1.9 min (35 ml kg-1/18 ml min-1 kg-1) in rainbow trout (Oncorhynchus mykiss). In air-breathing vertebrates, high metabolic rates...... are necessarily correlated with short circulation times. Our data are the first to imply that a similar relationship occurs in fishes....

  12. Modeling the Behavior of Red Blood Cells within the Caudal Vein Plexus of Zebrafish

    Science.gov (United States)

    Djukic, Tijana R.; Karthik, Swapna; Saveljic, Igor; Djonov, Valentin; Filipovic, Nenad

    2016-01-01

    Due to the important biological role of red blood cells (RBCs) in vertebrates, the analysis of reshaping and dynamics of RBCs motion is a critical issue in physiology and biomechanics. In this paper the behavior of RBCs within the immature capillary plexus during embryonic development of zebrafish has been analyzed. Relying on the fact that zebrafish embryos are small and optically transparent, it is possible to image the blood flow. In this way the anatomy of blood vessels is monitored along with the circulation throughout their development. Numerical simulations were performed using a specific numerical model that combines fluid flow simulation, modeling of the interaction of individual RBCs immersed in blood plasma with the surrounding fluid and modeling the deformation of individual cells. The results of numerical simulations are in accordance with the in vivo observed region of interest within the caudal vein plexus of the zebrafish embryo. Good agreement of results demonstrates the capabilities of the developed numerical model to predict and analyze the motion and deformation of RBCs in complex geometries. The proposed model (methodology) will help to elucidate different rheological and hematological related pathologies and finally to design better treatment strategies. PMID:27774070

  13. Magnetic Cycles and Meridional Circulation in Global Models of Solar Convection

    CERN Document Server

    Miesch, Mark S; Browning, Matthew K; Brun, Allan Sacha; Toomre, Juri

    2010-01-01

    We review recent insights into the dynamics of the solar convection zone obtained from global numerical simulations, focusing on two recent developments in particular. The first is quasi-cyclic magnetic activity in a long-duration dynamo simulation. Although mean fields comprise only a few percent of the total magnetic energy they exhibit remarkable order, with multiple polarity reversals and systematic variability on time scales of 6-15 years. The second development concerns the maintenance of the meridional circulation. Recent high-resolution simulations have captured the subtle nonlinear dynamical balances with more fidelity than previous, more laminar models, yielding more coherent circulation patterns. These patterns are dominated by a single cell in each hemisphere, with poleward and equatorward flow in the upper and lower convection zone respectively. We briefly address the implications of and future of these modeling efforts.

  14. THOR: A New and Flexible Global Circulation Model to Explore Planetary Atmospheres

    CERN Document Server

    Mendonça, João M; Grosheintz, Luc; Heng, Kevin

    2016-01-01

    We have designed and developed, from scratch, a global circulation model named THOR that solves the three-dimensional non-hydrostatic Euler equations. Our general approach lifts the commonly used assumptions of a shallow atmosphere and hydrostatic equilibrium. We solve the "pole problem" (where converging meridians on a sphere lead to increasingly smaller time steps near the poles) by implementing an icosahedral grid. Irregularities in the grid, which lead to grid imprinting, are smoothed using the "spring dynamics" technique. We validate our implementation of spring dynamics by examining calculations of the divergence and gradient of test functions. To prevent the computational time step from being bottlenecked by having to resolve sound waves, we implement a split-explicit method together with a horizontally explicit and vertically implicit integration. We validate our global circulation model by reproducing the Earth and also the hot Jupiter-like benchmark tests. THOR was designed to run on Graphics Proces...

  15. Regional eddy vorticity transport and the equilibrium vorticity budgets of a numerical model ocean circulation

    Science.gov (United States)

    Harrison, D. E.; Holland, W. R.

    1981-01-01

    A mean vorticity budget analysis is presented of Holland's (1978) numerical ocean general circulation experiment. The stable budgets are compared with classical circulation theory to emphasize the ways in which the mesoscale motions of the model alter (or leave unaltered) classical vorticity balances. The basinwide meridional transports of vorticity by the mean flow and by the mesoscale flow in the mean are evaluated to establish the role(s) of the mesoscale in the larger scale equilibrium vorticity transports. The vorticity equation for this model fluid system is presented and the budget analysis method is described. Vorticity budgets over the selected regions and on a larger scale are given, and a summary of budget results is provided along with remarks about the utility of this type of analysis.

  16. Crystal balls into the future: are global circulation and water balance models ready?

    Science.gov (United States)

    Fekete, Balázs M.; Pisacane, Giovanna; Wisser, Dominik

    2016-10-01

    Variabilities and changes due to natural and anthropogenic causes in the water cycle always presented a challenge for water management planning. Practitioners traditionally coped with variabilities in the hydrological processes by assuming stationarity in the probability distributions and attempted to address non-stationarity by revising this probabilistic properties via continued hydro-climatological observations. Recently, this practice was questioned and more reliance on Global Circulation Models was put forward as an alternative for water management plannig. This paper takes a brief assessment of the state of Global Circulation Models (GCM) and their applications by presenting case studies over Global, European and African domains accompanied by literature examples. Our paper demonstrates core deficiencies in GCM based water resources assessments and articulates the need for improved Earth system monitoring that is essential not only for water managers, but to aid the improvements of GCMs in the future.

  17. A model intercomparison of changes in the Atlantic thermohaline circulation in response to increasing atmospheric CO2 concentration

    OpenAIRE

    Gregory, J; Dixon, K; Stouffer, R.; Weaver, A.; E. Driesschaert; Eby, M.; Fichefet, T.; Hasumi, H.; Hu, A.; J. Jungclaus; Kamenkovich, I.; A. Levermann; Montoya, M.; Murakami, S.; Nawrath , S.

    2005-01-01

    As part of the Coupled Model Intercomparison Project, integrations with a common design have been undertaken with eleven different climate models to compare the response of the Atlantic thermohaline circulation ( THC) to time-dependent climate change caused by increasing atmospheric CO2 concentration. Over 140 years, during which the CO2 concentration quadruples, the circulation strength declines gradually in all models, by between 10 and 50%. No model shows a rapid or complete collapse, desp...

  18. A Review of Water Isotopes in Atmospheric General Circulation Models: Recent Advances and Future Prospects

    Directory of Open Access Journals (Sweden)

    Xi Xi

    2014-01-01

    Full Text Available Stable water isotopologues, mainly 1H2O, 1H2HO (HDO, and H12O18, are useful tracers for processes in the global hydrological cycle. The incorporation of water isotopes into Atmospheric General Circulation Models (AGCMs since 1984 has helped scientists gain substantial new insights into our present and past climate. In recent years, there have been several significant advances in water isotopes modeling in AGCMs. This paper reviews and synthesizes key advances accomplished in modeling (1 surface evaporation, (2 condensation, (3 supersaturation, (4 postcondensation processes, (5 vertical distribution of water isotopes, and (6 spatial δ18O-temperature slope and utilizing (1 spectral nudging technique, (2 higher model resolutions, and (3 coupled atmosphere-ocean models. It also reviews model validation through comparisons of model outputs and ground-based and spaceborne measurements. In the end, it identifies knowledge gaps and discusses future prospects of modeling and model validation.

  19. Turbulence, superrotation, and general circulation models of the atmosphere of Venus

    Science.gov (United States)

    Izakov, M. N.

    2016-09-01

    The data obtained in space-borne measurements and the findings of turbulence theory show that turbulence, of both small and large scales, has a decisive influence on the structure and dynamics of the atmosphere of Venus. The small-scale turbulence generates anomalous convection, while large-scale turbulence induces the return spectral flux of energy that is the main element of the superrotation mechanism in the atmosphere. Ways for improving the general circulation model of the atmosphere of Venus are proposed.

  20. Residual estuarine circulation in the Mandovi, a monsoonal estuary: A three-dimensional model study

    Digital Repository Service at National Institute of Oceanography (India)

    Vijith, V.; Shetye, S.R.; Baetens, K.; Luyten, P.; Michael, G.S.

    - nism, often referred to as tidal straining, was first proposed by Simpson et al. (1990) using an example from the Liverpool bay. They showed that during the flood tide, due to straining of horizontal density gradient, the water column destabilizes... circula- tion. Later, Stacey et al. (2008), using a numerical water column model, showed that the tidal straining component of the residual circulation is strongly dependent on the timing of stratification within the tidal cycle. Investigations on residual...

  1. Characterizing the surface circulation in Ebro Delta (NW Mediterranean) with HF radar and modeled current data

    Science.gov (United States)

    Lorente, P.; Piedracoba, S.; Sotillo, M. G.; Aznar, R.; Amo-Balandron, A.; Pascual, A.; Soto-Navarro, J.; Alvarez-Fanjul, E.

    2016-11-01

    Quality-controlled current observations from a High Frequency radar (HFR) network deployed in the Ebro River Delta (NW Mediterranean) were combined with outputs from IBI operational ocean forecasting system in order to comprehensively portray the ocean state and its variability during 2014. Accurate HFR data were used as benchmark for a rigorous validation of the Iberia-Biscay-Ireland (IBI) regional system, routinely operated in the frame of the Copernicus Marine Environment Monitoring Service (CMEMS). The analysis of skill metrics and monthly averaged current maps showed that IBI reasonably captured the prevailing dynamic features of the coastal circulation previously observed by the HFR, according to the moderate resemblance found in circulation patterns and the spatial distribution of eddy kinetic energy. The model skill assessment was completed with an exploration of dominant modes of spatiotemporal variability. The EOF analysis confirmed that the modeled surface current field evolved both in space and time according to three significantly dominant modes of variability which accounted for the 49.2% of the total variance, in close agreement with the results obtained for HFR (46.1%). The response of the subtidal surface current field to prevailing wind regime in the study area was examined in terms of induced circulation structures and immediacy of reaction by performing a conditional averaging approach and a time-lagged vector correlation analysis, respectively. This observations-model synergistic strategy has proved to be valid to operationally monitor the complex coastal circulation in Ebro Delta despite the observed model drawbacks in terms of reduced energy content in surface currents and some inaccuracies in the wind-driven low frequency response. This integrated methodology aids to improve the prognostic capabilities of IBI ocean forecasting system and also to facilitate high-stakes decision-making for coastal management in the Ebro River Delta marine

  2. Spectral analysis of CFB data: Predictive models of Circulating Fluidized Bed combustors

    Energy Technology Data Exchange (ETDEWEB)

    Gamwo, I.K.; Miller, A.; Gidaspow, D.

    1992-04-01

    The overall objective of this investigation is to develop experimentally verified models for circulating fluidized bed (CFB) combustors. Spectral analysis of CFB data obtained at Illinois Institute of Technology shows that the frequencies of pressure oscillations are less than 0.1 Hertz and that they increase with solids volume fraction to the usual value of one Hertz obtained in bubbling beds. These data are consistent with the kinetic theory interpretation of density wave propagation.

  3. Characterizing the surface circulation in the Ebro Delta using a HF radar data-model approach

    Science.gov (United States)

    Lorente Jimenez, Pablo; Piedracoba Varela, Silvia; Soto-Navarro, Javier; Garcia-Sotillo, Marcos; Alvarez Fanjul, Enrique

    2016-04-01

    One year-long (2014) quality-controlled current observations from a CODAR SeaSonde High Frequency (HF) radar network deployed in the Ebro Delta (northwestern Mediterranean) were combined with operational products provided by a regional ocean forecasting system named IBI (Iberia-Biscay-Ireland) in order to comprehensively portray the ocean state and its variability. First, accurate HF radar data were used as benchmark for the rigorous validation of IBI performance by means of the computation of skill metrics and quality indicators. The analysis of the monthly averaged current maps for 2014 showed that IBI properly captured the prevailing dynamic features of the coastal circulation observed by the HF radar, according to the resemblance of circulation patterns and the eddy kinetic energy spatial distribution. The model skill assessment was completed with an exploration of dominant modes of variability both in time and space. The EOF analysis confirmed that the modeled surface current field evolved in space and time according to three significantly dominant modes of variability which accounted for the 49.2% of the total variance, in close agreement with the results obtained for the HF radar (46.1%). The response of the subtidal surface current field to prevalent wind regimes in the study area was examined in terms of induced circulation structures by performing a conditional averaging approach. This data-model synergistic approach has proved to be valid to operationally monitor and describe the complex coastal circulation in Ebro Delta despite the observed model drawbacks in terms of reduced energy content in surface currents and some inaccuracies in the wind-driven low frequency response. This integrated methodology constitutes a powerful tool for improving operational ocean forecasting systems at European level within the frame of the Copernicus Marine Environment Monitoring Service (CMEMS). It also facilitates high-stakes decision-making for coastal management and

  4. MODELING STRATEGIES TO COMPUTE NATURAL CIRCULATION USING CFD IN A VHTR AFTER A LOFA

    Energy Technology Data Exchange (ETDEWEB)

    Yu-Hsin Tung; Richard W. Johnson; Ching-Chang Chieng; Yuh-Ming Ferng

    2012-11-01

    A prismatic gas-cooled very high temperature reactor (VHTR) is being developed under the next generation nuclear plant program (NGNP) of the U.S. Department of Energy, Office of Nuclear Energy. In the design of the prismatic VHTR, hexagonal shaped graphite blocks are drilled to allow insertion of fuel pins, made of compacted TRISO fuel particles, and coolant channels for the helium coolant. One of the concerns for the reactor design is the effects of a loss of flow accident (LOFA) where the coolant circulators are lost for some reason, causing a loss of forced coolant flow through the core. In such an event, it is desired to know what happens to the (reduced) heat still being generated in the core and if it represents a problem for the fuel compacts, the graphite core or the reactor vessel (RV) walls. One of the mechanisms for the transport of heat out of the core is by the natural circulation of the coolant, which is still present. That is, how much heat may be transported by natural circulation through the core and upwards to the top of the upper plenum? It is beyond current capability for a computational fluid dynamic (CFD) analysis to perform a calculation on the whole RV with a sufficiently refined mesh to examine the full potential of natural circulation in the vessel. The present paper reports the investigation of several strategies to model the flow and heat transfer in the RV. It is found that it is necessary to employ representative geometries of the core to estimate the heat transfer. However, by taking advantage of global and local symmetries, a detailed estimate of the strength of the resulting natural circulation and the level of heat transfer to the top of the upper plenum is obtained.

  5. Black carbon ageing in the Canadian Centre for Climate modelling and analysis atmospheric general circulation model

    Directory of Open Access Journals (Sweden)

    B. Croft

    2005-01-01

    Full Text Available Black carbon (BC particles in the atmosphere have important impacts on climate. The amount of BC in the atmosphere must be carefully quantified to allow evaluation of the climate effects of this type of aerosol. In this study, we present the treatment of BC aerosol in the developmental version of the 4th generation Canadian Centre for Climate modelling and analysis (CCCma atmospheric general circulation model (AGCM. The focus of this work is on the conversion of insoluble BC to soluble/mixed BC by physical and chemical ageing. Physical processes include the condensation of sulphuric and nitric acid onto the BC aerosol, and coagulation with more soluble aerosols such as sulphates and nitrates. Chemical processes that may age the BC aerosol include the oxidation of organic coatings by ozone. Four separate parameterizations of the ageing process are compared to a control simulation that assumes no ageing occurs. These simulations use 1 an exponential decay with a fixed 24h half-life, 2 a condensation and coagulation scheme, 3 an oxidative scheme, and 4 a linear combination of the latter two ageing treatments. Global BC burdens are 2.15, 0.15, 0.11, 0.21, and 0.11TgC for the control run, and four ageing schemes, respectively. The BC lifetimes are 98.1, 6.6, 5.0, 9.5, and 4.9 days, respectively. The sensitivity of modelled BC burdens, and concentrations to the factor of two uncertainty in the emissions inventory is shown to be greater than the sensitivity to the parameterization used to represent the BC ageing, except for the oxidation based parameterization. A computationally efficient parameterization that represents the processes of condensation, coagulation, and oxidation is shown to simulate BC ageing well in the CCCma AGCM. As opposed to the globally fixed ageing time scale, this treatment of BC ageing is responsive to varying atmospheric composition.

  6. Dynamics of indicators of a metabolic exchange and condition of blood circulation of the bottom extremities after traction extension at patients with lumbar and sacral dorsopathy

    OpenAIRE

    Kotenko К.V.; Korchazhkina N.B.; Petrova М.S.; Ruzova Т.К.

    2013-01-01

    Aim: to study influence of traction therapy in a pulse mode in a complex with electrotherapy on a condition of blood circulation of the bottom extremities and level of a metabolic exchange. Material and methods. There had been examined 120 patients with a lumbar and sacral dorsopathy aged from 22 to 69 years (middle age of 49,5 years) with prescription of a disease from 1 to 5 years, among them men of 34,2%, women of 65,8%. Results. The analysis of effects of various medical methods on a cond...

  7. Haemodynamic evaluation of the cerebral circulation by periorbital Doppler examination and cerebral blood flow (CBF) measurement in carotid artery disease

    DEFF Research Database (Denmark)

    Sillesen, H; Schroeder, T; Buchardt Hansen, H J

    1988-01-01

    To assess the haemodynamic significance of an internal carotid artery (ICA) stenosis, angiography or direct ultrasound examination should be supplemented by indirect physiologic testing of the collateral circulation. Among the tests proposed, we used the periorbital flow direction, assessed by Do...

  8. Superior efficacy of liposomal amphotericin B with prolonged circulation in blood in the treatment of severe candidiasis in leukopenic mice

    NARCIS (Netherlands)

    E.W.M. van Etten (Els); S.V. Snijders (Susan); W. van Vianen (Wim); I.A.J.M. Bakker-Woudenberg (Irma)

    1998-01-01

    textabstractIn leukopenic mice with severe systemic candidiasis, single-dose treatment (5 mg of amphotericin B [AMB]/kg of body weight) with long-circulating polyethylene glycol-coated AMB liposomes (PEG-AMB-LIP) resulted in zero mortality and a significant reduction in

  9. A heuristic simulation model of Lake Ontario circulation and mass balance transport

    Science.gov (United States)

    McKenna, J.E.; Chalupnicki, M.A.

    2011-01-01

    The redistribution of suspended organisms and materials by large-scale currents is part of natural ecological processes in large aquatic systems but can contribute to ecosystem disruption when exotic elements are introduced into the system. Toxic compounds and planktonic organisms spend various lengths of time in suspension before settling to the bottom or otherwise being removed. We constructed a simple physical simulation model, including the influence of major tributaries, to qualitatively examine circulation patterns in Lake Ontario. We used a simple mass balance approach to estimate the relative water input to and export from each of 10 depth regime-specific compartments (nearshore vs. offshore) comprising Lake Ontario. Despite its simplicity, our model produced circulation patterns similar to those reported by more complex studies in the literature. A three-gyre pattern, with the classic large counterclockwise central lake circulation, and a simpler two-gyre system were both observed. These qualitative simulations indicate little offshore transport along the south shore, except near the mouths of the Niagara River and Oswego River. Complex flow structure was evident, particularly near the Niagara River mouth and in offshore waters of the eastern basin. Average Lake Ontario residence time is 8 years, but the fastest model pathway indicated potential transport of plankton through the lake in as little as 60 days. This simulation illustrates potential invasion pathways and provides rough estimates of planktonic larval dispersal or chemical transport among nearshore and offshore areas of Lake Ontario. ?? 2011 Taylor & Francis.

  10. Ocean circulation model predicts high genetic structure observed in a long-lived pelagic developer.

    Science.gov (United States)

    Sunday, J M; Popovic, I; Palen, W J; Foreman, M G G; Hart, M W

    2014-10-01

    Understanding the movement of genes and individuals across marine seascapes is a long-standing challenge in marine ecology and can inform our understanding of local adaptation, the persistence and movement of populations, and the spatial scale of effective management. Patterns of gene flow in the ocean are often inferred based on population genetic analyses coupled with knowledge of species' dispersive life histories. However, genetic structure is the result of time-integrated processes and may not capture present-day connectivity between populations. Here, we use a high-resolution oceanographic circulation model to predict larval dispersal along the complex coastline of western Canada that includes the transition between two well-studied zoogeographic provinces. We simulate dispersal in a benthic sea star with a 6-10 week pelagic larval phase and test predictions of this model against previously observed genetic structure including a strong phylogeographic break within the zoogeographical transition zone. We also test predictions with new genetic sampling in a site within the phylogeographic break. We find that the coupled genetic and circulation model predicts the high degree of genetic structure observed in this species, despite its long pelagic duration. High genetic structure on this complex coastline can thus be explained through ocean circulation patterns, which tend to retain passive larvae within 20-50 km of their parents, suggesting a necessity for close-knit design of Marine Protected Area networks.

  11. PREDICTION OF BLOOD PATTERN IN S-SHAPED MODEL OF ARTERY UNDER NORMAL BLOOD PRESSURE

    Directory of Open Access Journals (Sweden)

    Mohd Azrul Hisham Mohd Adib

    2013-06-01

    Full Text Available Athletes are susceptible to a wide variety of traumatic and non-traumatic vascular injuries to the lower limb. This paper aims to predict the three-dimensional flow pattern of blood through an S-shaped geometrical artery model. This model has created by using Fluid Structure Interaction (FSI software. The modeling of the geometrical S-shaped artery is suitable for understanding the pattern of blood flow under constant normal blood pressure. In this study, a numerical method is used that works on the assumption that the blood is incompressible and Newtonian; thus, a laminar type of flow can be considered. The authors have compared the results with a previous study with FSI validation simulation. The validation and verification of the simulation studies is performed by comparing the maximum velocity at t = 0.4 s, because at this time, the blood accelerates rapidly. In addition, the resulting blood flow at various times, under the same boundary conditions in the S-shaped geometrical artery model, is presented. The graph shows that velocity increases linearly with time. Thus, it can be concluded that the flow of blood increases with respect to the pressure inside the body.

  12. Chinese Drugs That Invigorate Spleen to Remove Dampness and Activate Blood Circulation to Eliminate Turbid for Retarding Progression of Chronic Renal Failure

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Objective: To investigate the effect of Chinese drugs (CD) that invigorate Spleen to remove Dampness and activate the blood circulation to eliminate Turbid for retarding progression of chronic renal failure (CRF). Methods: Thirty-nine patients with CRF were divided into two groups at random: the 18 patients in group A (the control group) were treated with low protein diet and controlling blood pressure and 21 patients in group B (the treatment group) were treated similarly with that of the control group and additional CD. Levels of serous creatinine (SCr), blood urea nitrogen (BUN), blood albumin (Alb), total cholesterol (TC), triglyceride (TG), high-density lipoprotein (HDL) and hemoglobin (Hb) were checked every two months and the rate of progression of CRF was estimated by slope of the creatinine reciprocal (1/SCr) with time (months). Results: Levels of SCr and BUN in group B were lower and HDL higher than those in group A significantly, P<0.05. Mean slopes of the creatinine reciprocal with time in the two groups were markedly different, P<0.01. Conclusion: Additional CD treatment based upon the low protein diet and controlling blood pressure could retard the rate of progression of CRF evidently.

  13. A zonally symmetric model for the monsoon-Hadley circulation with stochastic convective forcing

    Science.gov (United States)

    De La Chevrotière, Michèle; Khouider, Boualem

    2016-09-01

    Idealized models of reduced complexity are important tools to understand key processes underlying a complex system. In climate science in particular, they are important for helping the community improve our ability to predict the effect of climate change on the earth system. Climate models are large computer codes based on the discretization of the fluid dynamics equations on grids of horizontal resolution in the order of 100 km, whereas unresolved processes are handled by subgrid models. For instance, simple models are routinely used to help understand the interactions between small-scale processes due to atmospheric moist convection and large-scale circulation patterns. Here, a zonally symmetric model for the monsoon circulation is presented and solved numerically. The model is based on the Galerkin projection of the primitive equations of atmospheric synoptic dynamics onto the first modes of vertical structure to represent free tropospheric circulation and is coupled to a bulk atmospheric boundary layer (ABL) model. The model carries bulk equations for water vapor in both the free troposphere and the ABL, while the processes of convection and precipitation are represented through a stochastic model for clouds. The model equations are coupled through advective nonlinearities, and the resulting system is not conservative and not necessarily hyperbolic. This makes the design of a numerical method for the solution of this system particularly difficult. Here, we develop a numerical scheme based on the operator time-splitting strategy, which decomposes the system into three pieces: a conservative part and two purely advective parts, each of which is solved iteratively using an appropriate method. The conservative system is solved via a central scheme, which does not require hyperbolicity since it avoids the Riemann problem by design. One of the advective parts is a hyperbolic diagonal matrix, which is easily handled by classical methods for hyperbolic equations, while

  14. Fluid Flow Modeling of Arc Plasma and Bath Circulation in DC Electric Arc Furnace

    Institute of Scientific and Technical Information of China (English)

    WANG Feng-hua; JIN Zhi-jian; ZHU Zi-shu

    2006-01-01

    A mathematical model describing the flow field, heat transfer and the electromagnetic phenomenon in a DC electric arc furnace has been developed. First the governing equations in the arc plasma region are solved and the calculated results of heat transfer, current density and shear stresses on the anode surface are used as boundary conditions in a model of molten bath. Then a two-dimensional time-dependent model is used to describe the flow field and electromagnetic phenomenon in the molten bath. Moreover, the effect of bottom electrode diameter on the circulation of molten bath is studied.

  15. A zonally symmetric model for the monsoon-Hadley circulation with stochastic convective forcing

    Science.gov (United States)

    De La Chevrotière, Michèle; Khouider, Boualem

    2017-02-01

    Idealized models of reduced complexity are important tools to understand key processes underlying a complex system. In climate science in particular, they are important for helping the community improve our ability to predict the effect of climate change on the earth system. Climate models are large computer codes based on the discretization of the fluid dynamics equations on grids of horizontal resolution in the order of 100 km, whereas unresolved processes are handled by subgrid models. For instance, simple models are routinely used to help understand the interactions between small-scale processes due to atmospheric moist convection and large-scale circulation patterns. Here, a zonally symmetric model for the monsoon circulation is presented and solved numerically. The model is based on the Galerkin projection of the primitive equations of atmospheric synoptic dynamics onto the first modes of vertical structure to represent free tropospheric circulation and is coupled to a bulk atmospheric boundary layer (ABL) model. The model carries bulk equations for water vapor in both the free troposphere and the ABL, while the processes of convection and precipitation are represented through a stochastic model for clouds. The model equations are coupled through advective nonlinearities, and the resulting system is not conservative and not necessarily hyperbolic. This makes the design of a numerical method for the solution of this system particularly difficult. Here, we develop a numerical scheme based on the operator time-splitting strategy, which decomposes the system into three pieces: a conservative part and two purely advective parts, each of which is solved iteratively using an appropriate method. The conservative system is solved via a central scheme, which does not require hyperbolicity since it avoids the Riemann problem by design. One of the advective parts is a hyperbolic diagonal matrix, which is easily handled by classical methods for hyperbolic equations, while

  16. Model prediction of the operating behavior of a circulating fluidized bed boiler

    Institute of Scientific and Technical Information of China (English)

    王勤辉; 骆仲泱; 倪明江; 岑可法

    2002-01-01

    An improved mathematical model for a circulating fluidized bed (CFB) boiler based on the model developed earlier by the authors was applied to simulate the operation of a 12 MW CFB boiler. The influences of the excess air ratio, primary air ratio, coal particle size distribution, coal properties (ash content and volatile content) and Ca/S ratio on the boiler operation were analyzed. The results showed that the model simulation may be applied to the optimum design and economic operation of the CFB boiler.

  17. Model prediction of the operating behavior of a circulating fluidized bed boiler

    Institute of Scientific and Technical Information of China (English)

    王勤辉; 骆仲泱; 倪明江; 岑可法

    2002-01-01

    An improved mathematical model for a circulating fluidized bed (CFB) boiler baaed on the model developed earlier by the authors was applied to simulate the operation of a 12 MW CFB boiler.The influences of the excess air ratio, primary air ratio, coal particle size distribution, coal properties (ash content and volatile content) and Ca/S ratio on the boiler operation were analyzed. The results showed that the model simulation may be applied to the optimum design and economic operation of the CFB boiler.

  18. Using a {sigma}-coordinate numerical ocean model for simulating the circulation at Ormen Lange

    Energy Technology Data Exchange (ETDEWEB)

    Eliassen, Inge K.; Berntsen, Jarle

    2000-01-01

    This report describes a numerical model for the simulation of circulation at the Ormen Lange oil field. The model uses a topography following vertical coordinate and time split integration procedure. The model is implemented for a 28 km x 46 km area at Ormen Lange. The equations are given in detail and numerical experiments are discussed. The numerical studies investigate how the flow specified at open boundaries surrounding the Ormen Lange area may be interpolated into the interior domain taking into account the conservation laws that are believed to determine the flow and the local topography.

  19. Theoretical discussion on promoting blood circulation and removing blood stasis therapy for restless leg syndrome%活血化瘀法治疗不宁腿综合征的理论探讨

    Institute of Scientific and Technical Information of China (English)

    赵阳; 刁倩; 李涛

    2012-01-01

    传统治疗思路认为具有柔肝养阴、缓急止痛作用的芍药甘草汤是治疗不宁腿综合征(restless legs syndrome,RLS)的有效方剂.但笔者通过临床实践、结合古代文献及中医药理论认为,血脉瘀阻是RLS的主要病机,活血化瘀应是治疗RLS的核心疗法.%Peony and Licorice Decoction was effective in treating Restless leg syndrome(RLS) with the function of nourishing yin for softening liver,relaxing spasm and relieving pain.Clinical practice,ancient literature and Chinese medicine theory were comprehensively studied to conclude that blood stasis is the key cause of RLS.Promoting blood circulation and removing blood stasis was the crucial therapy for RLS.

  20. Numerical simulations of a reduced model for blood coagulation

    Science.gov (United States)

    Pavlova, Jevgenija; Fasano, Antonio; Sequeira, Adélia

    2016-04-01

    In this work, the three-dimensional numerical resolution of a complex mathematical model for the blood coagulation process is presented. The model was illustrated in Fasano et al. (Clin Hemorheol Microcirc 51:1-14, 2012), Pavlova et al. (Theor Biol 380:367-379, 2015). It incorporates the action of the biochemical and cellular components of blood as well as the effects of the flow. The model is characterized by a reduction in the biochemical network and considers the impact of the blood slip at the vessel wall. Numerical results showing the capacity of the model to predict different perturbations in the hemostatic system are discussed.

  1. Vertical heat flux in the ocean: Estimates from observations and from a coupled general circulation model

    Science.gov (United States)

    Cummins, Patrick F.; Masson, Diane; Saenko, Oleg A.

    2016-06-01

    The net heat uptake by the ocean in a changing climate involves small imbalances between the advective and diffusive processes that transport heat vertically. Generally, it is necessary to rely on global climate models to study these processes in detail. In the present study, it is shown that a key component of the vertical heat flux, namely that associated with the large-scale mean vertical circulation, can be diagnosed over extra-tropical regions from global observational data sets. This component is estimated based on the vertical velocity obtained from the geostrophic vorticity balance, combined with estimates of absolute geostrophic flow. Results are compared with the output of a non-eddy resolving, coupled atmosphere-ocean general circulation model. Reasonable agreement is found in the latitudinal distribution of the vertical heat flux, as well as in the area-integrated flux below about 250 m depth. The correspondence with the coupled model deteriorates sharply at depths shallower than 250 m due to the omission of equatorial regions from the calculation. The vertical heat flux due to the mean circulation is found to be dominated globally by the downward contribution from the Southern Hemisphere, in particular the Southern Ocean. This is driven by the Ekman vertical velocity which induces an upward transport of seawater that is cold relative to the horizontal average at a given depth. The results indicate that the dominant characteristics of the vertical transport of heat due to the mean circulation can be inferred from simple linear vorticity dynamics over much of the ocean.

  2. Identification of age- and disease-related alterations in circulating miRNAs in a mouse model of Alzheimer's disease

    Directory of Open Access Journals (Sweden)

    Sylvia eGarza-Manero

    2015-02-01

    Full Text Available Alzheimer's disease (AD is a neurodegenerative disorder characterized clinically by the progressive decline of memory and cognition. Histopathologically, two main hallmarks have been identified in AD: amyloid-β peptide extracellular neuritic plaques and neurofibrillary tangles formed by posttranslational modified tau protein. A definitive diagnosis can only be achieved after the post mortem verification of the histological mentioned alterations. Therefore the development of biomarkers that allow an early diagnosis and/or predict disease progression is imperative. The prospect of a blood-based biomarker is possible with the finding of circulating microRNAs (miRNAs, a class of small non-coding RNAs of 22-25 nucleotides length that regulate mRNA translation rate. miRNAs travel through blood and recent studies performed in potential AD cases suggest the possibility of finding pathology-associated differences in circulating miRNA levels that may serve to assist in early diagnosis of the disease. However, these studies analyzed samples at a single time-point, limiting the use of miRNAs as biomarkers in AD progression. In this study we evaluated miRNA levels in plasma samples at different time-points of the evolution of an AD-like pathology in a transgenic mouse model of the disease (3xTg-AD. We performed multiplex qRT-PCR and compared the plasmatic levels of 84 miRNAs previously associated to central nervous system development and disease. No significant differences were detected between WT and transgenic young mice. However, age-related significant changes in miRNA abundance were observed for both WT and transgenic mice, and some of these were specific for the 3xTg-AD. In agreement, variations in the levels of particular miRNAs were identified between WT and transgenic old mice thus suggesting that the age-dependent evolution of the AD-like pathology, rather than the presence and expression of the transgenes, modifies the circulating miRNA levels in

  3. Quantitative image cytometry measurements of lipids, DNA, CD45 and cytokeratin for circulating tumor cell identification in a model system

    Science.gov (United States)

    Futia, Gregory L.; Qamar, Lubna; Behbakht, Kian; Gibson, Emily A.

    2016-04-01

    Circulating tumor cell (CTC) identification has applications in both early detection and monitoring of solid cancers. The rarity of CTCs, expected at ~1-50 CTCs per million nucleated blood cells (WBCs), requires identifying methods based on biomarkers with high sensitivity and specificity for accurate identification. Discovery of biomarkers with ever higher sensitivity and specificity to CTCs is always desirable to potentially find more CTCs in cancer patients thus increasing their clinical utility. Here, we investigate quantitative image cytometry measurements of lipids with the biomarker panel of DNA, Cytokeratin (CK), and CD45 commonly used to identify CTCs. We engineered a device for labeling suspended cell samples with fluorescent antibodies and dyes. We used it to prepare samples for 4 channel confocal laser scanning microscopy. The total data acquired at high resolution from one sample is ~ 1.3 GB. We developed software to perform the automated segmentation of these images into regions of interest (ROIs) containing individual cells. We quantified image features of total signal, spatial second moment, spatial frequency second moment, and their product for each ROI. We performed measurements on pure WBCs, cancer cell line MCF7 and mixed samples. Multivariable regressions and feature selection were used to determine combination features that are more sensitive and specific than any individual feature separately. We also demonstrate that computation of spatial characteristics provides higher sensitivity and specificity than intensity alone. Statistical models allowed quantification of the required sensitivity and specificity for detecting small levels of CTCs in a human blood sample.

  4. Biochemical assessment of growth factors and circulation of blood components contained in the different fractions obtained by centrifugation of venous blood.

    Science.gov (United States)

    Corigiano, M; Ciobanu, G; Baldoni, E; Pompa, G

    2014-01-01

    The aim of this study was to evaluate a biochemical marker with different elements of a normal blood serum and centrifuged blood serum after a different rotation system. For this technique, we used five fractions of a blood Concentrated Growth Factors system (bCGF) and a particular device for the different rotation program. Blood samples were collected from 10 volunteers aged between 35 and 55 in the Operative Unit of the “Sapienza” University of Rome with only a fraction of different biochemical elements. Through an individual blood phase separator tube of venous blood, active factions of serum and 4 fractions of red buffy coat were taken. The biochemical markers with 14 elements were examined at times: P1-11 minutes, P2-12minutes, P3-15 minutes. Exclusively biological materials which are normally applied in the regeneration techniques for different defects and lesions were used with this technique. After specific rotation programs, a different result was obtained for each cycle: P1, P2, P3. In test tubes obtained by separated blood, we observed a higher concentration of proteins, ions, and other antigens compared to normal blood plasma. Examining the biochemical results of different elements, we observed an increase (P≤0,01). Since each person’s DNA is different, we could not have the same results in 5 fractions of blood concentration, we did, however, find a good increase in only a fraction of proteins, immunoglobulin and different ions. We obtained five fractions after centrifugation, and we had an increase in different biochemical elements compared to normal blood (P≤0,01) which is significant at different times. These biochemical elements were stimulated by different growth factors, which are used by the immune system, and they induced the formation of hard and soft tissues and good regeneration.

  5. The spread amongst ENSEMBLES regional scenarios: regional climate models, driving general circulation models and interannual variability

    Energy Technology Data Exchange (ETDEWEB)

    Deque, M.; Somot, S. [Meteo-France, Centre National de Recherches Meteorologiques, CNRS/GAME, Toulouse Cedex 01 (France); Sanchez-Gomez, E. [Cerfacs/CNRS, SUC URA1875, Toulouse Cedex 01 (France); Goodess, C.M. [University of East Anglia, Climatic Research Unit, Norwich (United Kingdom); Jacob, D. [Max Planck Institute for Meteorology, Hamburg (Germany); Lenderink, G. [KNMI, Postbus 201, De Bilt (Netherlands); Christensen, O.B. [Danish Meteorological Institute, Copenhagen Oe (Denmark)

    2012-03-15

    Various combinations of thirteen regional climate models (RCM) and six general circulation models (GCM) were used in FP6-ENSEMBLES. The response to the SRES-A1B greenhouse gas concentration scenario over Europe, calculated as the difference between the 2021-2050 and the 1961-1990 means can be viewed as an expected value about which various uncertainties exist. Uncertainties are measured here by variance explained for temperature and precipitation changes over eight European sub-areas. Three sources of uncertainty can be evaluated from the ENSEMBLES database. Sampling uncertainty is due to the fact that the model climate is estimated as an average over a finite number of years (30) despite a non-negligible interannual variability. Regional model uncertainty is due to the fact that the RCMs use different techniques to discretize the equations and to represent sub-grid effects. Global model uncertainty is due to the fact that the RCMs have been driven by different GCMs. Two methods are presented to fill the many empty cells of the ENSEMBLES RCM x GCM matrix. The first one is based on the same approach as in FP5-PRUDENCE. The second one uses the concept of weather regimes to attempt to separate the contribution of the GCM and the RCM. The variance of the climate response is analyzed with respect to the contribution of the GCM and the RCM. The two filling methods agree that the main contributor to the spread is the choice of the GCM, except for summer precipitation where the choice of the RCM dominates the uncertainty. Of course the implication of the GCM to the spread varies with the region, being maximum in the South-western part of Europe, whereas the continental parts are more sensitive to the choice of the RCM. The third cause of spread is systematically the interannual variability. The total uncertainty about temperature is not large enough to mask the 2021-2050 response which shows a similar pattern to the one obtained for 2071-2100 in PRUDENCE. The uncertainty

  6. Real-Time Statistical Modeling of Blood Sugar.

    Science.gov (United States)

    Otoom, Mwaffaq; Alshraideh, Hussam; Almasaeid, Hisham M; López-de-Ipiña, Diego; Bravo, José

    2015-10-01

    Diabetes is considered a chronic disease that incurs various types of cost to the world. One major challenge in the control of Diabetes is the real time determination of the proper insulin dose. In this paper, we develop a prototype for real time blood sugar control, integrated with the cloud. Our system controls blood sugar by observing the blood sugar level and accordingly determining the appropriate insulin dose based on patient's historical data, all in real time and automatically. To determine the appropriate insulin dose, we propose two statistical models for modeling blood sugar profiles, namely ARIMA and Markov-based model. Our experiment used to evaluate the performance of the two models shows that the ARIMA model outperforms the Markov-based model in terms of prediction accuracy.

  7. Numerical Modelling Approaches for Assessing Improvements to the Flow Circulation in a Small Lake

    Directory of Open Access Journals (Sweden)

    Cheng He

    2011-01-01

    Full Text Available Kamaniskeg Lake is a long, narrow, and deep small lake located in the northern part of Ontario, Canada. The goals of this paper were to examine various options to improve the water quality in the northern part of the lake by altering the local hydraulic flow conditions. Towards this end, a preliminary screening suggested that the flow circulation could be increased around a central island (Mask Island in the northern part of the lake by opening up an existing causeway connecting the mainland and central island. Three-dimensional (3D hydraulic and transport models were adopted in this paper to investigate the hydraulic conditions under various wind forces and causeway structures. The modelling results show that opening the causeway in a few places is unlikely to generate a large flow circulation around the central island. Full circulation only appears to be possible if the causeway is fully removed and a strong wind blows in a favourable direction. The possible reasons for existing water quality variations at the intake of a local WTP (water treatment plant are also explored in the paper.

  8. Variational data assimilation system with nesting model for high resolution ocean circulation

    Energy Technology Data Exchange (ETDEWEB)

    Ishikawa, Yoichi; Igarashi, Hiromichi; Hiyoshi, Yoshimasa; Sasaki, Yuji; Wakamatsu, Tsuyoshi; Awaji, Toshiyuki [Center for Earth Information Science and Technology, Japan Agency for Marine-Earth Science and Technology, 3173-25 Showa-machi, Kanazawa-Ku, Yokohama 236-0001 (Japan); In, Teiji [Japan Marine Science Foundation, 4-24, Minato-cho, Mutsu, Aomori, 035-0064 (Japan); Nakada, Satoshi [Graduate School of Maritime Science, Kobe University, 5-1-1, Fukae-minamimachi, Higashinada-Ku, Kobe, 658-0022 (Japan); Nishina, Kei, E-mail: ishikaway@jamstec.go.jp [Graduate School of Science, Kyoto University, Kitashirakawaoiwake-cho, Sakyo-Ku, Kyoto, 606-8502 (Japan)

    2015-10-15

    To obtain the high-resolution analysis fields for ocean circulation, a new incremental approach is developed using a four-dimensional variational data assimilation system with nesting models. The results show that there are substantial biases when using a classical method combined with data assimilation and downscaling, caused by different dynamics resulting from the different resolutions of the models used within the nesting models. However, a remarkable reduction in biases of the low-resolution model relative to the high-resolution model was observed using our new approach in narrow strait regions, such as the Tsushima and Tsugaru straits, where the difference in the dynamics represented by the high- and low-resolution models is substantial. In addition, error reductions are demonstrated in the downstream region of these narrow channels associated with the propagation of information through the model dynamics. (paper)

  9. Computational modeling of blood flow steal phenomena caused by subclavian stenoses.

    Science.gov (United States)

    Blanco, P J; Müller, L O; Watanabe, S M; Feijóo, R A

    2016-06-14

    The study of steal mechanisms caused by vessel obstructions is of the utmost importance to gain understanding about their pathophysiology, as well as to improve diagnosis and management procedures. The goal of this work is to perform a computational study to gain insight into the hemodynamic forces that drive blood flow steal mechanisms caused by subclavian artery stenosis. Such condition triggers a flow disorder known as subclavian steal. When this occurs in patients with internal thoracic artery anastomosed to the coronary vessels, the phenomenon includes a coronary-subclavian steal. True steal can exist in cases of increased arm blood flow, potentially resulting in neurological complications and, in the case of coronary-subclavian steal, graft function failure. In this context, the anatomically detailed arterial network (ADAN) model is employed to simulate subclavian steal and coronary-subclavian steal phenomena. Model results are verified by comparison with published data. It is concluded that this kind of model allows us to effectively address complex hemomdynamic phenomena occurring in clinical practice. More specifically, in the studied conditions it is observed that a regional brain steal occurs, primarily affecting the posterior circulation, not fully compensated by the anterior circulation. In the case of patients with coronary revascularization, it is concluded that there is a large variability in graft hemodynamic environments, which physically explain both the success of the procedure in cases of severe occlusive disease, and the reason for graft dysfunction in mildly stenosed left anterior descending coronary artery, due to alternating graft flow waveform signatures.

  10. PERFORMANCE MODELING AND ANALYSIS OF BLOOD FLOW IN ELASTIC ARTERIES

    Institute of Scientific and Technical Information of China (English)

    Anil Kumar; C.L. Varshney; G.C. Sharma

    2005-01-01

    Two different non-Newtonian models for blood flow are considered, first a simple power law model displaying shear thinning viscosity, and second a generalized Maxwell model displaying both shear thinning viscosity and oscillating flow viscous-elasticity. These models are used along with a Newtonian model to study sinusoidal flow of blood in rigid and elastic straight arteries in the presence of magnetic field. The elasticity of blood does not appear to influence its flow behavior under physiological conditions in the large arteries,purely viscous shear thinning model should be quite realistic for simulating blood flow under these conditions. On using the power law model with high shear rate for sinusoidal flow simulation in elastic arteries, the mean and amplitude of the flow rate were found to be lower for a power law fluid compared to Newtonian fluid for the same pressure gradient. The governing equations have been solved by Crank-Niclson scheme. The results are interpreted in the context of blood in the elastic arteries keeping the magnetic effects in view. For physiological flow simulation in the aorta, an increase in mean wall shear stress, but a reduction in peak wall shear stress were observed for power law model compared to a Newtonian fluid model for matched flow rate wave form. Blood flow in the presence of transverse magnetic field in an elastic artery is investigated and the influence of factors such as morphology and surface irregularity is evaluated.

  11. AFP mRNA level in enriched circulating tumor cells from hepatocellular carcinoma patient blood samples is a pivotal predictive marker for metastasis.

    Science.gov (United States)

    Jin, Junhua; Niu, Xiaojuan; Zou, Lihui; Li, Lin; Li, Shugang; Han, Jingli; Zhang, Peiying; Song, Jinghai; Xiao, Fei

    2016-08-01

    Circulating tumor cells (CTCs) quantification may be helpful for evaluating cancer dissemination, predicting prognosis and assessing therapeutic effectiveness and safety. In the present study, CTCs from blood samples of 72 patients with hepatocellular carcinoma (HCC) were enriched with anti-EpCAM nanoparticles. AFP mRNA level was detected by nested polymerase chain reaction (PCR) after enrichment of CTCs from HCC blood samples at 0, 3, 6, 9 and 12 months after hepatectomy, respectively. AFP mRNA expression in CTCs was positive in 43 patients (59.7%) and negative in 29 patients (40.3%) before hepatectomy. Among 43 patients with positive AFP mRNA expression in CTCs before hepatectomy, 10 and 11 were diagnosed as intrahepatic/extrahepatic metastasis before and after hepatectomy, respectively. In addition, these 21 patients with metastasis had persisting positive AFP mRNA of CTCs during the whole tested year. Specifically, 3 patients with AFP mRNA negative in CTCs before hepatectomy changed to be positive at 6 and 9 months, and 2 of them were diagnosed as metastasis 12 months after hepatectomy. We conclude that the positive AFP mRNA of CTCs can be a pivotal predictor for HCC metastasis before and after hepatectomy. The release of AFP expression from hepatocellular carcinoma cells into circulation must be a major source of HCC metastasis.

  12. Circulating angiotensin II gains access to the hypothalamus and brain stem during hypertension via breakdown of the blood-brain barrier.

    Science.gov (United States)

    Biancardi, Vinicia Campana; Son, Sook Jin; Ahmadi, Sahra; Filosa, Jessica A; Stern, Javier E

    2014-03-01

    Angiotensin II-mediated vascular brain inflammation emerged as a novel pathophysiological mechanism in neurogenic hypertension. However, the precise underlying mechanisms and functional consequences in relation to blood-brain barrier (BBB) integrity and central angiotensin II actions mediating neurohumoral activation in hypertension are poorly understood. Here, we aimed to determine whether BBB permeability within critical hypothalamic and brain stem regions involved in neurohumoral regulation was altered during hypertension. Using digital imaging quantification after intravascularly injected fluorescent dyes and immunohistochemistry, we found increased BBB permeability, along with altered key BBB protein constituents, in spontaneously hypertensive rats within the hypothalamic paraventricular nucleus, the nucleus of the solitary tract, and the rostral ventrolateral medulla, all critical brain regions known to contribute to neurohumoral activation during hypertension. BBB disruption, including increased permeability and downregulation of constituent proteins, was prevented in spontaneously hypertensive rats treated with the AT1 receptor antagonist losartan, but not with hydralazine, a direct vasodilator. Importantly, we found circulating angiotensin II to extravasate into these brain regions, colocalizing with neurons and microglial cells. Taken together, our studies reveal a novel angiotensin II-mediated feed-forward mechanism during hypertension, by which circulating angiotensin II evokes increased BBB permeability, facilitating in turn its access to critical brain regions known to participate in blood pressure regulation.

  13. Design and Performance Analysis of a Massively Parallel Atmospheric General Circulation Model

    Directory of Open Access Journals (Sweden)

    Daniel S. Schaffer

    2000-01-01

    Full Text Available In the 1990's, computer manufacturers are increasingly turning to the development of parallel processor machines to meet the high performance needs of their customers. Simultaneously, atmospheric scientists studying weather and climate phenomena ranging from hurricanes to El Niño to global warming require increasingly fine resolution models. Here, implementation of a parallel atmospheric general circulation model (GCM which exploits the power of massively parallel machines is described. Using the horizontal data domain decomposition methodology, this FORTRAN 90 model is able to integrate a 0.6° longitude by 0.5° latitude problem at a rate of 19 Gigaflops on 512 processors of a Cray T3E 600; corresponding to 280 seconds of wall-clock time per simulated model day. At this resolution, the model has 64 times as many degrees of freedom and performs 400 times as many floating point operations per simulated day as the model it replaces.

  14. Primary Reasoning behind the Double ITCZ Phenomenon in a Coupled Ocean-Atmosphere General Circulation Model

    Institute of Scientific and Technical Information of China (English)

    李江龙; 张学洪; 俞永强; 戴福山

    2004-01-01

    This paper investigates the processes behind the double ITCZ phenomenon, a common problem in Coupled ocean-atmosphere General Circulation Models (CGCMs), using a CGCM-FGCM-0 (Flexible General Circulation Model, version 0). The double ITCZ mode develops rapidly during the first two years of the integration and becomes a perennial phenomenon afterwards in the model. By way of Singular Value Decomposition (SVD) for SST, sea surface pressure, and sea surface wind, some air-sea interactions are analyzed. These interactions prompt the anomalous signals that appear at the beginning of the coupling to develop rapidly. There are two possible reasons, proved by sensitivity experiments: (1) the overestimated east-west gradient of SST in the equatorial Pacific in the ocean spin-up process, and (2) the underestimated amount of low-level stratus over the Peruvian coast in CCM3 (the Community Climate Model, Version Three). The overestimated east-west gradient of SST brings the anomalous equatorial easterly. The anomalous easterly, affected by the Coriolis force in the Southern Hemisphere, turns into an anomalous westerly in a broad area south of the equator and is enhanced by atmospheric anomalous circulation due to the underestimated amount of low-level stratus over the Peruvian coast simulated by CCM3. The anomalous westerly leads to anomalous warm advection that makes the SST warm in the southeast Pacific.The double ITCZ phenomenon in the CGCM is a result of a series of nonlocal and nonlinear adjustment processes in the coupled system, which can be traced to the uncoupled models, oceanic component, and atmospheric component. The zonal gradient of the equatorial SST is too large in the ocean component and the amount of low-level stratus over the Peruvian coast is too low in the atmosphere component.

  15. Atmospheric circulation in regional climate models over Central Europe: links to surface air temperature and the influence of driving data

    Energy Technology Data Exchange (ETDEWEB)

    Plavcova, Eva [Institute of Atmospheric Physics, Academy of Sciences of the Czech Republic, Prague 4 (Czech Republic); Technical University, Department of Applied Mathematics, Liberec (Czech Republic); Charles University, Faculty of Mathematics and Physics, Prague (Czech Republic); Kysely, Jan [Institute of Atmospheric Physics, Academy of Sciences of the Czech Republic, Prague 4 (Czech Republic); Technical University, Department of Applied Mathematics, Liberec (Czech Republic)

    2012-10-15

    The study examines simulation of atmospheric circulation, represented by circulation indices (flow direction, strength and vorticity), and links between circulation and daily surface air temperatures in regional climate models (RCMs) over Central Europe. We explore control simulations of five high-resolution RCMs from the ENSEMBLES project driven by re-analysis (ERA-40) and the same global climate model (ECHAM5 GCM) plus of one RCM (RCA) driven by different GCMs. The aims are to (1) identify errors in RCM-simulated distributions of circulation indices in individual seasons, (2) identify errors in simulated temperatures under particular circulation indices, and (3) compare performance of individual RCMs with respect to the driving data. Although most of the RCMs qualitatively reflect observed distributions of the airflow indices, each produces distributions significantly different from the observations. General biases include overestimation of the frequency of strong flow days and of strong cyclonic vorticity. Some circulation biases obviously propagate from the driving data. ECHAM5 and all simulations driven by ECHAM5 underestimate frequency of easterly flow, mainly in summer. Except for HIRHAM, however, all RCMs driven by ECHAM5 improve on the driving GCM in simulating atmospheric circulation. The influence on circulation characteristics in the nested RCM differs between GCMs, as demonstrated in a set of RCA simulations with different driving data. The driving data control on circulation in RCA is particularly weak for the BCM GCM, in which case RCA substantially modifies (but does not improve) the circulation from the driving data in both winter and summer. Those RCMs with the most distorted atmospheric circulation are HIRHAM driven by ECHAM5 and RCA driven by BCM. Relatively strong relationships between circulation indices and surface air temperatures were found in the observed data for Central Europe. The links differ by season and are usually stronger for

  16. General circulation modeling of the thermosphere-ionosphere during a geomagnetic storm

    Science.gov (United States)

    Yiǧit, Erdal; Immel, Thomas; Ridley, Aaron; Frey, Harald U.; Moldwin, Mark

    2016-07-01

    Using a three-dimensional general circulation model (GCM) of the upper atmosphere, we investigate the response of the thermosphere-ionosphere system to the August 2011 major geomagnetic storm. The GCM is driven by measured storm-time input data of the Interplanetary Magnetic Field (IMF), solar activity, and auroral activity. Simulations for quiet steady conditions over the same period are performed as well in order to assess the response of the neutral and plasma parameters to the storm. During the storm, the high-latitude mean ion flows are enhanced by up to ~150%. Overall, the global mean neutral temperature increases by up to 15%, while the maximum thermal response is higher in the winter Southern Hemisphere at high-latitudes than the summer Northern Hemisphere: 40% vs. 20% increase in high-latitude mean temperature, respectively. The global mean Joule heating of the neutral atmosphere increases by more than a factor of three. There are distinct hemispheric differences in the magnitude and morphology of the horizontal ion flows and thermospheric circulation during the different phases of the storm. The thermospheric circulation demonstrates the largest amount of hemispheric differences during the later stages of the storm. Dynamical diagnostics show that advective forcing contributes to hemispheric differences.

  17. Modeling ocean circulation and biogeochemical variability in the Gulf of Mexico

    Science.gov (United States)

    Xue, Z.; He, R.; Fennel, K.; Cai, W.-J.; Lohrenz, S.; Hopkinson, C.

    2013-11-01

    A three-dimensional coupled physical-biogeochemical model is applied to simulate and examine temporal and spatial variability of circulation and biogeochemical cycling in the Gulf of Mexico (GoM). The model is driven by realistic atmospheric forcing, open boundary conditions from a data assimilative global ocean circulation model, and observed freshwater and terrestrial nitrogen input from major rivers. A 7 yr model hindcast (2004-2010) was performed, and validated against satellite observed sea surface height, surface chlorophyll, and in situ observations including coastal sea level, ocean temperature, salinity, and dissolved inorganic nitrogen (DIN) concentration. The model hindcast revealed clear seasonality in DIN, phytoplankton and zooplankton distributions in the GoM. An empirical orthogonal function analysis indicated a phase-locked pattern among DIN, phytoplankton and zooplankton concentrations. The GoM shelf nitrogen budget was also quantified, revealing that on an annual basis the DIN input is largely balanced by the removal through denitrification (an equivalent of ~ 80% of DIN input) and offshore exports to the deep ocean (an equivalent of ~ 17% of DIN input).

  18. Numerical modeling of the thermoelectric cooler with a complementary equation for heat circulation in air gaps

    Science.gov (United States)

    Fang, En; Wu, Xiaojie; Yu, Yuesen; Xiu, Junrui

    2017-01-01

    In this paper, a numerical model is developed by combining thermodynamics with heat transfer theory. Taking inner and external multi-irreversibility into account, it is with a complementary equation for heat circulation in air gaps of a steady cooling system with commercial thermoelectric modules operating in refrigeration mode. With two modes concerned, the equation presents the heat flowing through air gaps which forms heat circulations between both sides of thermoelectric coolers (TECs). In numerical modelling, a TEC is separated as two temperature controlled constant heat flux reservoirs in a thermal resistance network. In order to obtain the parameter values, an experimental apparatus with a commercial thermoelectric cooler was built to characterize the performance of a TEC with heat source and sink assembly. At constant power dissipation, steady temperatures of heat source and both sides of the thermoelectric cooler were compared with those in a standard numerical model. The method displayed that the relationship between Φf and the ratio Φ_{c}'/Φ_{c} was linear as expected. Then, for verifying the accuracy of proposed numerical model, the data in another system were recorded. It is evident that the experimental results are in good agreement with simulation(proposed model) data at different heat transfer rates. The error is small and mainly results from the instabilities of thermal resistances with temperature change and heat flux, heat loss of the device vertical surfaces and measurements.

  19. Modeling ocean circulation and biogeochemical variability in the Gulf of Mexico

    Directory of Open Access Journals (Sweden)

    Z. Xue

    2013-05-01

    Full Text Available A three-dimensional coupled physical-biogeochemical model is applied to simulate and examine temporal and spatial variability of circulation and biogeochemical cycling in the Gulf of Mexico (GoM. The model is driven by realistic atmospheric forcing, open boundary conditions from a data assimilative global ocean circulation model, and observed freshwater and terrestrial nutrient input from major rivers. A 7 yr model hindcast (2004–2010 was performed, and validated against satellite observed sea surface height, surface chlorophyll, and in-situ observations including coastal sea-level, ocean temperature, salinity, and nutrient concentration. The model hindcast revealed clear seasonality in nutrient, phytoplankton and zooplankton distributions in the GoM. An Empirical Orthogonal Function analysis indicated a phase-locked pattern among nutrient, phytoplankton and zooplankton concentrations. The GoM shelf nutrient budget was also quantified, revealing that on an annual basis ~80% of nutrient input was denitrified on the shelf and ~17% was exported to the deep ocean.

  20. Modelling the ocean circulation on the West Greenland shelf with special emphasis on northern shrimp recruitment

    Science.gov (United States)

    Hvid Ribergaard, Mads; Anker Pedersen, Søren; Ådlandsvik, Bjørn; Kliem, Nicolai

    2004-08-01

    The ocean circulation on the West Greenland shelf are modelled using a 3D finite element circulation model forced by wind data from the Danish Meteorological Institute-High-Resolution Limited Area Model operational atmospheric model for the Greenland area and tides at the open boundary. Residual anticyclonic eddies are generated around the shelf banks north of 64∘N and areas of permanent upwelling are located west of the shelf banks. The potential distances of shrimp larvae transport from larval release to settling at the bottom were studied, using a particle-tracking model. Particles released (hatched shrimp larvae) south of 62∘N had a probability of about 2% of being lost to the Canadian Shelf, whereas for particles released north of 64∘N almost none were lost from the West Greenland Shelf. The particles tended to have long retention times at the shelf banks caused by the residual anticyclonic eddies. The retention times increased slightly for particles tracked at depths from 80 to 30 m with minor implications for potential transport distances of larval shrimp and plankton.

  1. Assessment of a six gene panel for the molecular detection of circulating tumor cells in the blood of female cancer patients

    Directory of Open Access Journals (Sweden)

    Horvat Reinhard

    2010-12-01

    Full Text Available Abstract Background The presence of circulating tumor cells (CTC in the peripheral blood of cancer patients has been described for various solid tumors and their clinical relevance has been shown. CTC detection based on the analysis of epithelial antigens might be hampered by the genetic heterogeneity of the primary tumor and loss of epithelial antigens. Therefore, we aimed to identify new gene markers for the PCR-based detection of CTC in female cancer patients. Methods Gene expression of 38 cancer cell lines (breast, ovarian, cervical and endometrial and of 10 peripheral blood mononuclear cell (PBMC samples from healthy female donors was measured using microarray technology (Applied Biosystems. Differentially expressed genes were identified using the maxT test and the 50% one-sided trimmed maxT-test. Confirmatory RT-qPCR was performed for 380 gene targets using the AB TaqMan® Low Density Arrays. Then, 93 gene targets were analyzed using the same RT-qPCR platform in tumor tissues of 126 patients with primary breast, ovarian or endometrial cancer. Finally, blood samples from 26 healthy women and from 125 patients (primary breast, ovarian, cervical, or endometrial cancer, and advanced breast cancer were analyzed following OncoQuick enrichment and RNA pre-amplification. Likewise, hMAM and EpCAM gene expression was analyzed in the blood of breast and ovarian cancer patients. For each gene, a cut-off threshold value was set at three standard deviations from the mean expression level of the healthy controls to identify potential markers for CTC detection. Results Six genes were over-expressed in blood samples from 81% of patients with advanced and 29% of patients with primary breast cancer. EpCAM gene expression was detected in 19% and 5% of patients, respectively, whereas hMAM gene expression was observed in the advanced group (39% only. Multimarker analysis using the new six gene panel positively identified 44% of the cervical, 64% of the

  2. An Eddy-Permitting Oceanic General Circulation Model and Its Preliminary Evaluation

    Institute of Scientific and Technical Information of China (English)

    刘海龙; 张学洪; 李薇; 俞永强; 宇如聪

    2004-01-01

    An eddy-permitting, quasi-global oceanic general circulation model, LICOM (LASG/IAP (State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics, Institute of Atmospheric Physics) Climate System Ocean Model), with a uniform grid of 0.5°× 0.5° is established.Forced by wind stresses from Hellerman and Rosenstain (1983), a 40-yr integration is conducted with sea surface temperature and salinity being restored to the Levitus 94 datasets. The evaluation of the annual mean climatology of the LICOM control run shows that the large-scale circulation can be well reproduced. A comparison between the LICOM control run and a parallel integration of L30T63, which has the same framework but a coarse resolution, is also made to confirm the impact of resolution on the model performance. On account of the reduction of horizontal viscosity with the enhancement of the horizontal resolution, LICOM improves the simulation with respect to not only the intensity of the large scale circulations, but also the magnitude and structureof the Equatorial Undercurrent and South Equatorial Current. Taking advantage of the fine grid size, the pathway of the Indonesian Throughflow (ITF) is better represented in LICOM than in L30T63. The transport of ITF in LICOM is more convergent in the upper layer. As a consequence, the Indian Ocean tends to get warmer in LICOM. The poleward heat transports for both the global and individual basins are also significantly improved in LICOM. A decomposed analysis indicates that the transport due to the barotropic gyre, which primarily stands for the barotropic effect of the western boundary currents, plays a crucial role in making the difference.

  3. An approach for modeling thermal destruction of hazardous wastes in circulating fluidized bed incinerator.

    Science.gov (United States)

    Patil, M P; Sonolikar, R L

    2008-10-01

    This paper presents a detailed computational fluid dynamics (CFD) based approach for modeling thermal destruction of hazardous wastes in a circulating fluidized bed (CFB) incinerator. The model is based on Eular - Lagrangian approach in which gas phase (continuous phase) is treated in a Eularian reference frame, whereas the waste particulate (dispersed phase) is treated in a Lagrangian reference frame. The reaction chemistry hasbeen modeled through a mixture fraction/ PDF approach. The conservation equations for mass, momentum, energy, mixture fraction and other closure equations have been solved using a general purpose CFD code FLUENT4.5. Afinite volume method on a structured grid has been used for solution of governing equations. The model provides detailed information on the hydrodynamics (gas velocity, particulate trajectories), gas composition (CO, CO2, O2) and temperature inside the riser. The model also allows different operating scenarios to be examined in an efficient manner.

  4. A global multiscale mathematical model for the human circulation with emphasis on the venous system.

    Science.gov (United States)

    Müller, Lucas O; Toro, Eleuterio F

    2014-07-01

    We present a global, closed-loop, multiscale mathematical model for the human circulation including the arterial system, the venous system, the heart, the pulmonary circulation and the microcirculation. A distinctive feature of our model is the detailed description of the venous system, particularly for intracranial and extracranial veins. Medium to large vessels are described by one-dimensional hyperbolic systems while the rest of the components are described by zero-dimensional models represented by differential-algebraic equations. Robust, high-order accurate numerical methodology is implemented for solving the hyperbolic equations, which are adopted from a recent reformulation that includes variable material properties. Because of the large intersubject variability of the venous system, we perform a patient-specific characterization of major veins of the head and neck using MRI data. Computational results are carefully validated using published data for the arterial system and most regions of the venous system. For head and neck veins, validation is carried out through a detailed comparison of simulation results against patient-specific phase-contrast MRI flow quantification data. A merit of our model is its global, closed-loop character; the imposition of highly artificial boundary conditions is avoided. Applications in mind include a vast range of medical conditions. Of particular interest is the study of some neurodegenerative diseases, whose venous haemodynamic connection has recently been identified by medical researchers.

  5. Reconciling the observed and modeled Southern Hemisphere circulation response to volcanic eruptions

    Science.gov (United States)

    McGraw, Marie C.; Barnes, Elizabeth A.; Deser, Clara

    2016-07-01

    Confusion exists regarding the tropospheric circulation response to volcanic eruptions, with models and observations seeming to disagree on the sign of the response. The forced Southern Hemisphere circulation response to the eruptions of Pinatubo and El Chichón is shown to be a robust positive annular mode, using over 200 ensemble members from 38 climate models. It is demonstrated that the models and observations are not at odds, but rather, internal climate variability is large and can overwhelm the forced response. It is further argued that the state of the El Niño-Southern Oscillation can at least partially explain the sign of the observed anomalies and may account for the perceived discrepancy between model and observational studies. The eruptions of both El Chichón and Pinatubo occurred during El Niño events, and it is demonstrated that the Southern Annular Mode anomalies following volcanic eruptions are weaker during El Niño events compared to La Niña events.

  6. Modified graphical autocatalytic set model of combustion process in circulating fluidized bed boiler

    Science.gov (United States)

    Yusof, Nurul Syazwani; Bakar, Sumarni Abu; Ismail, Razidah

    2014-07-01

    Circulating Fluidized Bed Boiler (CFB) is a device for generating steam by burning fossil fuels in a furnace operating under a special hydrodynamic condition. Autocatalytic Set has provided a graphical model of chemical reactions that occurred during combustion process in CFB. Eight important chemical substances known as species were represented as nodes and catalytic relationships between nodes are represented by the edges in the graph. In this paper, the model is extended and modified by considering other relevant chemical reactions that also exist during the process. Catalytic relationship among the species in the model is discussed. The result reveals that the modified model is able to gives more explanation of the relationship among the species during the process at initial time t.

  7. Modeling and simulation of the effects of landslide on circulation of transports on the mountain roads

    Directory of Open Access Journals (Sweden)

    Manh Hung Nguyen

    2015-08-01

    Full Text Available Landslides, as one of the major natural hazards, account each year for enormous property damage in terms of both direct and indirect costs. Mountain roads where probability of land sliding is the highest, causes hurdles not only in the traffic flow but generate various traffic problems in the form of congestion, high accidents rate and waste of time. This paper introduces an agent-based model for modeling and simulation of the effects of landslide on the circulation of transports on mountain roads. This model is applied to the National Road N°6 of Vietnam to visualize and analyze the effects of landslide on the road when it occurs. This model could help us to improve and optimally organize of landslide warning and rescue system on the road.

  8. Martian aeolian features and deposits - Comparisons with general circulation model results

    Science.gov (United States)

    Greeley, Ronald; Skypeck, Andrew; Pollack, James B.

    1993-01-01

    The relationships between near-surface winds and the distribution of wind-related features are investigated by means of a general circulation model of Mars' atmosphere. Predictions of wind surface stress as a function of season and dust optical depth are used to investigate the distribution and orientation of wind streaks, yardangs, and rock abundance on the surface. The global distribution of rocks on the surface correlates well with predicted wind stress, particularly during the dust storm season. The rocky areas are sites of strong winds, suggesting that fine material is swept away by the wind, leaving rocks and coarser material behind.

  9. Results of an interactively coupled atmospheric chemistry - general circulation model. Comparison with observations

    Energy Technology Data Exchange (ETDEWEB)

    Hein, R.; Dameris, M.; Schnadt, C. [and others

    2000-01-01

    An interactively coupled climate-chemistry model which enables a simultaneous treatment of meteorology and atmospheric chemistry and their feedbacks is presented. This is the first model, which interactively combines a general circulation model based on primitive equations with a rather complex model of stratospheric and tropospheric chemistry, and which is computational efficient enough to allow long-term integrations with currently available computer resources. The applied model version extends from the Earth's surface up to 10 hPa with a relatively high number (39) of vertical levels. We present the results of a present-day (1990) simulation and compare it to available observations. We focus on stratospheric dynamics and chemistry relevant to describe the stratospheric ozone layer. The current model version ECHAM4.L39(DLR)/CHEM can realistically reproduce stratospheric dynamics in the Arctic vortex region, including stratospheric warming events. This constitutes a major improvement compared to formerly applied model versions. However, apparent shortcomings in Antarctic circulation and temperatures persist. The seasonal and interannual variability of the ozone layer is simulated in accordance with observations. Activation and deactivation of chlorine in the polar stratospheric vortices and their interhemispheric differences are reproduced. The consideration of the chemistry feedback on dynamics results in an improved representation of the spatial distribution of stratospheric water vapor concentrations, i.e., the simulated meriodional water vapor gradient in the stratosphere is realistic. The present model version constitutes a powerful tool to investigate, for instance, the combined direct and indirect effects of anthropogenic trace gas emissions, and the future evolution of the ozone layer. (orig.)

  10. Effects of wave-induced forcing on a circulation model of the North Sea

    Science.gov (United States)

    Staneva, Joanna; Alari, Victor; Breivik, Øyvind; Bidlot, Jean-Raymond; Mogensen, Kristian

    2017-01-01

    The effect of wind waves on water level and currents during two storms in the North Sea is investigated using a high-resolution Nucleus for European Modelling of the Ocean (NEMO) model forced with fluxes and fields from a high-resolution wave model. The additional terms accounting for wave-current interaction that are considered in this study are the Stokes-Coriolis force, the sea-state-dependent energy and momentum fluxes. The individual and collective role of these processes is quantified and the results are compared with a control run without wave effects as well as against current and water-level measurements from coastal stations. We find a better agreement with observations when the circulation model is forced by sea-state-dependent fluxes, especially in extreme events. The two extreme events, the storm Christian (25-27 October 2013), and about a month later, the storm Xaver (5-7 December 2013), induce different wave and surge conditions over the North Sea. Including the wave effects in the circulation model for the storm Xaver raises the modelled surge by more than 40 cm compared with the control run in the German Bight area. For the storm Christian, a difference of 20-30 cm in the surge level between the wave-forced and the stand-alone ocean model is found over the whole southern part of the North Sea. Moreover, the modelled vertical velocity profile fits the observations very well when the wave forcing is accounted for. The contribution of wave-induced forcing has been quantified indicating that this represents an important mechanism for improving water-level and current predictions.

  11. Effect of Chinese Drugs for Supplementing Qi, Nourishing Yin and Activating Blood Circulation on Myocardial Perfusion in Patients with Acute Myocardial Infarction after Revascularization

    Institute of Scientific and Technical Information of China (English)

    LI Yong-qiang; JIN Mei; QIU Sheng-lei; WANG Pei-li; ZHU Tian-gang; WANG Cheng-long; LI Tian-chang; LIU Hong-xu; BIAN Hong; YAO Li-fang; SHI Da-zhuo

    2009-01-01

    Objective: To observe the effects of Chinese drugs for supplementing qi, nourishing yin and activating blood circulation on the myocardial perfusion in acute myocardial infarction (AMI) patients after revascularization. Methods: Eighty patients with anterior or inferior ventricular wall AMI, who had received revascularization by intravenous thrombolysis or coronary bypass, were randomized into the treated group and the control group equally, both treated with conventional Western medical treatment, but combined, respectively, Dobutamine stress echocardiography (DSE) was performed 14 days and 3 months after revascularization, respectively on every patient to observe blood perfusion extent (b value), myocardial perfusion velocity (k value) and local blood flow volume (k × b) in left ventricular infarction-related vascular segments under stressed state. Results: With 5 cases dropping out in the observation pedod (3 in the treated group and 2 in the control group), the tdal was completed in 75 patients in total. The 14-day DSE shows that the b value and k×b value of left anterior ventricular wall mid segment and apex segment, and the k value of apex segment in patients with antedor wall AMI, as well as the b value and k×b of basel segment in patients with infedor wall AMI in the treated group were significantly higher than those in the control group (P<0.05 or P<0.01). The 3-month DSE shows that the b value of apex segment, k×b value of basal segment, mid segment and apex segment of left anterior ventdcular wall in patients with anterior wall AMI as well as the b value and k x b value of basal segment of left infedor ventricular wall in patients with inferior wall AMI were all higher in the treated group than those in the control group, respectively (P<0.05). The comparison between 14-day DSE and 3-month DSE in the treated group showed that the b value of apex segment of left antedor ventdcular wall in patients with antedor wall AMI and the k×b value of apex

  12. Improved short-term variability in the thermosphere-ionosphere-mesosphere-electrodynamics general circulation model

    Science.gov (United States)

    Häusler, K.; Hagan, M. E.; Baumgaertner, A. J. G.; Maute, A.; Lu, G.; Doornbos, E.; Bruinsma, S.; Forbes, J. M.; Gasperini, F.

    2014-08-01

    We report on a new source of tidal variability in the National Center for Atmospheric Research thermosphere-ionosphere-mesosphere-electrodynamics general circulation model (TIME-GCM). Lower boundary forcing of the TIME-GCM for a simulation of November-December 2009 based on 3-hourly Modern-Era Retrospective Analysis for Research and Application (MERRA) reanalysis data includes day-to-day variations in both diurnal and semidiurnal tides of tropospheric origin. Comparison with TIME-GCM results from a heretofore standard simulation that includes climatological tropospheric tides from the global-scale wave model reveal evidence of the impacts of MERRA forcing throughout the model domain, including measurable tidal variability in the TIME-GCM upper thermosphere. Additional comparisons with measurements made by the Gravity field and steady-state Ocean Circulation Explorer satellite show improved TIME-GCM capability to capture day-to-day variations in thermospheric density for the November-December 2009 period with the new MERRA lower boundary forcing.

  13. Numerical simulation and artificial neural network modeling of natural circulation boiling water reactor

    Energy Technology Data Exchange (ETDEWEB)

    Garg, A. [Department of Mechanical Engineering, Indian Institute of Technology Guwahati, Guwahati 781039, Assam (India); Sastry, P.S. [Department of Mechanical Engineering, Indian Institute of Technology Guwahati, Guwahati 781039, Assam (India); Pandey, M. [Department of Mechanical Engineering, Indian Institute of Technology Guwahati, Guwahati 781039, Assam (India)]. E-mail: manmohan@iitg.ac.in; Dixit, U.S. [Department of Mechanical Engineering, Indian Institute of Technology Guwahati, Guwahati 781039, Assam (India); Gupta, S.K. [Atomic Energy Regulatory Board, Mumbai 400085 (India)

    2007-02-15

    Numerical simulation of natural circulation boiling water reactor is important in order to study its performance for different designs and under various off-design conditions. Numerical simulations can be performed by using thermal-hydraulic codes. Very fast numerical simulations, useful for extensive parametric studies and for solving design optimization problems, can be achieved by using an artificial neural network (ANN) model of the system. In the present work, numerical simulations of natural circulation boiling water reactor have been performed with RELAP5 code for different values of design parameters and operational conditions. Parametric trends observed have been discussed. The data obtained from these simulations have been used to train artificial neural networks, which in turn have been used for further parametric studies and design optimization. The ANN models showed error within {+-}5% for all the simulated data. Two most popular methods, multilayer perceptron (MLP) and radial basis function (RBF) networks, have been used for the training of ANN model. Sequential quadratic programming (SQP) has been used for optimization.

  14. Constraining a Martian general circulation model with the MAVEN/IUVS observations in the thermosphere

    Science.gov (United States)

    Moeckel, Chris; Medvedev, Alexander; Nakagawa, Hiromu; Evans, Scott; Kuroda, Takeshi; Hartogh, Paul; Yiğit, Erdal; Jain, Sonal; Lo, Daniel; Schneider, Nicholas M.; Jakosky, Bruce

    2016-10-01

    The recent measurements of the number density of atomic oxygen by Mars Atmosphere and Volatile EvolutioN/ Imaging UltraViolet Spectrograph (MAVEN/IUVS) have been implemented for the first time into a global circulation model to quantify the effect on the Martian thermosphere. The number density has been converted to 1D volume mixing ratio and this profile is compared to the atomic oxygen scenarios based on chemical models. Simulations were performed with the Max Planck Institute Martian General Circulation Model (MPI-MGCM). The simulations closely emulate the conditions at the time of observations. The results are compared to the IUVS-measured CO2 number density and temperature above 130 km to gain knowledge of the processes in the upper atmosphere and further constrain them in MGCMs. The presentation will discuss the role and importance in the thermosphere of the following aspects: (a) impact of the observed atomic oxygen, (b) 27-day solar cycle variations, (c) varying dust load in the lower atmosphere, and (d) gravity waves.

  15. Integrated cumulus ensemble and turbulence (ICET): An integrated parameterization system for general circulation models (GCMs)

    Energy Technology Data Exchange (ETDEWEB)

    Evans, J.L.; Frank, W.M.; Young, G.S. [Pennsylvania State Univ., University Park, PA (United States)

    1996-04-01

    Successful simulations of the global circulation and climate require accurate representation of the properties of shallow and deep convective clouds, stable-layer clouds, and the interactions between various cloud types, the boundary layer, and the radiative fluxes. Each of these phenomena play an important role in the global energy balance, and each must be parameterized in a global climate model. These processes are highly interactive. One major problem limiting the accuracy of parameterizations of clouds and other processes in general circulation models (GCMs) is that most of the parameterization packages are not linked with a common physical basis. Further, these schemes have not, in general, been rigorously verified against observations adequate to the task of resolving subgrid-scale effects. To address these problems, we are designing a new Integrated Cumulus Ensemble and Turbulence (ICET) parameterization scheme, installing it in a climate model (CCM2), and evaluating the performance of the new scheme using data from Atmospheric Radiation Measurement (ARM) Program Cloud and Radiation Testbed (CART) sites.

  16. Hepatitis B virus and hepatitis D virus in blood donors from Argentina: circulation of HBsAg and reverse transcriptase mutants.

    Science.gov (United States)

    Delfino, Cecilia María; Gentile, Emiliano Alberto; Castillo, Amalia Inés; Cuestas, María Luján; Pataccini, Gabriela; Cánepa, Camila; Malan, Richard; Blejer, Jorgelina; Berini, Carolina; Eirin, María Emilia; Pedrozo, Williams; Oubiña, José Raúl; Biglione, Mirna Marcela; Mathet, Verónica Lidia

    2014-05-01

    In Argentina, current procedures to ensure the safety of the blood supply for transfusion include the serologic detection of specific blood-borne infections. The aim of this study was to evaluate the prevalence and the genetic diversity of hepatitis B virus (HBV) and hepatitis D virus (HDV) in blood donor populations from two distantly located Argentine regions. Data from 56,983 blood donations from the Favaloro Foundation, in the city of Buenos Aires (Central Region), and the Central Blood Bank of Misiones Province (Northeast Region) were analyzed. Samples that were reactive for HBsAg were analyzed for HBV-DNA characterization and HDV serological and molecular analysis. The HBV prevalence was 0.12 % for HBsAg and 1.68 % for anti-HBc antibodies in Buenos Aires, and 0.73 % and 8.55 %, respectively, in Misiones. Seventy-seven HBsAg-reactive samples were analyzed by polymerase chain reaction for HBV-DNA. Subgenotypes A2, B2, C2, F1b and F4 (Buenos Aires) and F1b and D3 (Misiones) were detected. Several mutations within the major hydrophilic region of HBsAg, the reverse transcriptase, the basal core promoter, and the precore/core were detected. HDV genotype 1 was identified in Buenos Aires. This study confirms the circulation of several HBV subgenotypes, as well as known and newly identified variants, and the presence of HDV1 in this population. A thorough investigation has to be carried out to evaluate the clinical importance of some of the documented mutations as well as those detected in the HDV1 case.

  17. Explicit entrainment parameterization in the general circulation model ECHAM5-HAM

    Science.gov (United States)

    Siegenthaler-Le Drian, Colombe; Spichtinger, Peter; Lohmann, Ulrike

    2010-05-01

    The complex interactions affecting cloud lifetime and liquid water path (LWP) are not well captured in state-of-the-art general circulation models (GCM). A recent climate model intercomparison showed an overestimation of the positive correlation of LWP with aerosol optical depth by a factor of two as compared to MODIS data for almost all participating models (Quaas et al., 2009). As the authors suggest, a proper interaction of the boundary layer dynamics, particularly the inclusion of cloud top entrainment may lead to an improvement. ECHAM5 was one of the participating model. In this model, the turbulent fluxes in the planetary boundary layer are simulated using a turbulent kinetic energy - mixing length scheme. It has been showed that its performance diminishes when the resolution decreases, the different fluxes being not represented satisfactory with 31 vertical levels, particularly at the cloud top (Lenderink et al., 2000). We thus replace the turbulent fluxes by the explicit entrainment closure by Turton and Nicholls (1987) at the top of the stratocumulus capped boundary layers. The turbulent fluxes are weighted with the cloud cover to apply the entrainment closure only above clouds. In addition, we use an explicit term for the radiative cooling contribution in the buoyancy production term. We use the new version of the Hamburg general circulation model ECHAM5-HAM (Roeckner et al., 2003; Stier et al., 2005). The cloud scheme that is used for this study includes the double-moment cloud microphysics scheme for cloud droplets and ice crystals (Lohmann et al., 2007). The principal effect of the explicit entrainment is to dry and warm the planetary boundary layer. The averaged profiles are more stable and the inversion is reduced. The stratocumulus deck is reduced in all typical stratocumulus regions. In a single column version of the model, the diurnal cycle simulated in cloud cover or equivalentely in cloud water is much more representative of observed subtropical

  18. In vivo acoustic and photoacoustic focusing of circulating cells

    Science.gov (United States)

    Galanzha, Ekaterina I.; Viegas, Mark G.; Malinsky, Taras I.; Melerzanov, Alexander V.; Juratli, Mazen A.; Sarimollaoglu, Mustafa; Nedosekin, Dmitry A.; Zharov, Vladimir P.

    2016-03-01

    In vivo flow cytometry using vessels as natural tubes with native cell flows has revolutionized the study of rare circulating tumor cells in a complex blood background. However, the presence of many blood cells in the detection volume makes it difficult to count each cell in this volume. We introduce method for manipulation of circulating cells in vivo with the use of gradient acoustic forces induced by ultrasound and photoacoustic waves. In a murine model, we demonstrated cell trapping, redirecting and focusing in blood and lymph flow into a tight stream, noninvasive wall-free transportation of blood, and the potential for photoacoustic detection of sickle cells without labeling and of leukocytes targeted by functionalized nanoparticles. Integration of cell focusing with intravital imaging methods may provide a versatile biological tool for single-cell analysis in circulation, with a focus on in vivo needleless blood tests, and preclinical studies of human diseases in animal models.

  19. Identification of six potential markers for the detection of circulating canine mammary tumour cells in the peripheral blood identified by microarray analysis.

    Science.gov (United States)

    da Costa, A; Lenze, D; Hummel, M; Kohn, B; Gruber, A D; Klopfleisch, R

    2012-01-01

    The presence of circulating tumour cells (CTCs) in the peripheral blood is a prognostic factor for survival of human breast cancer patients. CTCs in the peripheral blood of dogs with mammary tumours have not been reported definitively. The present pilot study identifies mRNA markers for CTCs by comparing the transcriptome of canine mammary carcinoma cell lines CMM26 and CMM115 and peripheral blood leucocytes (PBLs). Genes with a 200-fold or higher mRNA expression in carcinoma cell lines were tested for specificity and sensitivity to detect CTCs using reverse transcriptase polymerase chain reaction (PCR). Six mRNA markers, AGR2, ATP8B1, CRYAB, F3 IRX3 and SLC1A1 were expressed in cell lines, but not PBL. All PCRs were able to detect one carcinoma cell admixed in 10(6) or more PBLs. The six mRNA markers may be suitable for detection of canine mammary CTCs and allow the analysis of their spatiotemporal distribution in dogs with mammary tumours.

  20. Effect of the Principle of Activating Blood Circulation to Break Stasis on GMP-140 and D2 Dimer in Patients with Acute Cerebral Infarction

    Institute of Scientific and Technical Information of China (English)

    WANG Ning

    2005-01-01

    Objective:To explore the clinical efficacy of the principle of activating blood circulation to break stasis (ABCBS) and its influence on platelet membranous protein particle (GMP-140) and D2 dimer (Ddimer) before and after treatment. Methods: Eighty-eight patients with blood stasis syndrome (BSS) of acute cerebral infarction (ACI) were randomly divided into two groups, both of which were treated with conventional treatment, i.e. with western medicine (WM), with Salvia injection added through intravenously dripping.One of the two groups was used as the control and the other group as the treated group who had ABCBS herbs orally taken in addition. The duration of treatment course for both groups was 3 weeks. Results: There were changes in both groups over clinical symptoms, nerve function deficit scoring and GMP-140, D-dimer, but the treated group showed significantly better than that of the control group, (P<0.05). Conclusion: ABCBS principle could serve as an important auxiliary treating method for BSS of ACI, as it can effectively alter the blood of ACI patients which was viscous, condense, coagulant and aggregating.

  1. Using Green's Functions to initialize and adjust a global, eddying ocean biogeochemistry general circulation model

    Science.gov (United States)

    Brix, H.; Menemenlis, D.; Hill, C.; Dutkiewicz, S.; Jahn, O.; Wang, D.; Bowman, K.; Zhang, H.

    2015-11-01

    The NASA Carbon Monitoring System (CMS) Flux Project aims to attribute changes in the atmospheric accumulation of carbon dioxide to spatially resolved fluxes by utilizing the full suite of NASA data, models, and assimilation capabilities. For the oceanic part of this project, we introduce ECCO2-Darwin, a new ocean biogeochemistry general circulation model based on combining the following pre-existing components: (i) a full-depth, eddying, global-ocean configuration of the Massachusetts Institute of Technology general circulation model (MITgcm), (ii) an adjoint-method-based estimate of ocean circulation from the Estimating the Circulation and Climate of the Ocean, Phase II (ECCO2) project, (iii) the MIT ecosystem model "Darwin", and (iv) a marine carbon chemistry model. Air-sea gas exchange coefficients and initial conditions of dissolved inorganic carbon, alkalinity, and oxygen are adjusted using a Green's Functions approach in order to optimize modeled air-sea CO2 fluxes. Data constraints include observations of carbon dioxide partial pressure (pCO2) for 2009-2010, global air-sea CO2 flux estimates, and the seasonal cycle of the Takahashi et al. (2009) Atlas. The model sensitivity experiments (or Green's Functions) include simulations that start from different initial conditions as well as experiments that perturb air-sea gas exchange parameters and the ratio of particulate inorganic to organic carbon. The Green's Functions approach yields a linear combination of these sensitivity experiments that minimizes model-data differences. The resulting initial conditions and gas exchange coefficients are then used to integrate the ECCO2-Darwin model forward. Despite the small number (six) of control parameters, the adjusted simulation is significantly closer to the data constraints (37% cost function reduction, i.e., reduction in the model-data difference, relative to the baseline simulation) and to independent observations (e.g., alkalinity). The adjusted air-sea gas

  2. Simulations of physics and chemistry of polar stratospheric clouds with a general circulation model

    Energy Technology Data Exchange (ETDEWEB)

    Buchholz, J.

    2005-04-20

    A polar stratospheric cloud submodel has been developed and incorporated in a general circulation model including atmospheric chemistry (ECHAM5/MESSy). The formation and sedimentation of polar stratospheric cloud (PSC) particles can thus be simulated as well as heterogeneous chemical reactions that take place on the PSC particles. For solid PSC particle sedimentation, the need for a tailor-made algorithm has been elucidated. A sedimentation scheme based on first order approximations of vertical mixing ratio profiles has been developed. It produces relatively little numerical diffusion and can deal well with divergent or convergent sedimentation velocity fields. For the determination of solid PSC particle sizes, an efficient algorithm has been adapted. It assumes a monodisperse radii distribution and thermodynamic equilibrium between the gas phase and the solid particle phase. This scheme, though relatively simple, is shown to produce particle number densities and radii within the observed range. The combined effects of the representations of sedimentation and solid PSC particles on vertical H{sub 2}O and HNO{sub 3} redistribution are investigated in a series of tests. The formation of solid PSC particles, especially of those consisting of nitric acid trihydrate, has been discussed extensively in recent years. Three particle formation schemes in accordance with the most widely used approaches have been identified and implemented. For the evaluation of PSC occurrence a new data set with unprecedented spatial and temporal coverage was available. A quantitative method for the comparison of simulation results and observations is developed and applied. It reveals that the relative PSC sighting frequency can be reproduced well with the PSC submodel whereas the detailed modelling of PSC events is beyond the scope of coarse global scale models. In addition to the development and evaluation of new PSC submodel components, parts of existing simulation programs have been

  3. The modern and glacial overturning circulation in the Atlantic ocean in PMIP coupled model simulations

    Directory of Open Access Journals (Sweden)

    S. L. Weber

    2007-01-01

    Full Text Available This study analyses the response of the Atlantic meridional overturning circulation (AMOC to LGM forcings and boundary conditions in nine PMIP coupled model simulations, including both GCMs and Earth system Models of Intermediate Complexity. Model results differ widely. The AMOC slows down considerably (by 20–40% during the LGM as compared to the modern climate in four models, there is a slight reduction in one model and four models show a substantial increase in AMOC strength (by 10–40%. It is found that a major controlling factor for the AMOC response is the density contrast between Antarctic Bottom Water (AABW and North Atlantic Deep Water (NADW at their source regions. Changes in the density contrast are determined by the opposing effects of changes in temperature and salinity, with more saline AABW as compared to NADW consistently found in all models and less cooling of AABW in all models but one. In only two models is the AMOC response during the LGM directly related to the response in net evaporation over the Atlantic basin. Most models show large changes in the ocean freshwater transports into the basin, but this does not seem to affect the AMOC response. Finally, there is some dependence on the accuracy of the control state.

  4. Physical Modeling of the Vacuum Circulation Refining Process of Molten Steel

    Institute of Scientific and Technical Information of China (English)

    魏季和

    2003-01-01

    The available studies in the literature on physical modeling of the vacuum circulation (RH, i.e. Ruhrstahl-Heraeus) refining process of molten steel have briefly been reviewed. The latest advances made by the author with his research group have been summarized. Water modeling was employed to investigate the flow and mixing characteristics of molten steel under the RH and RH-KTB (Kawasaki top blowing) conditions and the mass transfer features between molten steel and powder particles in the RH-PTB (powder top blowing) refining. The geometric similarity ratio between the model and its prototype (a multifunction RH degasser of 90 t capacity) was 1:5. The effects of the related technological and structural factors were considered. These latest studies have revealed the flow and mixing characteristics of molten steel and the mass transfer features between molten steel and powder particles in these processes, and have provided a better understanding of the refining processes of molten steel.

  5. A two-time-level split-explicit ocean circulation model (MASNUM) and its validation

    Institute of Scientific and Technical Information of China (English)

    HAN Lei

    2014-01-01

    A two-time-level, three-dimensional numerical ocean circulation model (named MASNUM) was estab-lished with a two-level, single-step Eulerian forward-backward time-differencing scheme. A mathematical model of large-scale oceanic motions was based on the terrain-following coordinated, Boussinesq, Reyn-olds-averaged primitive equations of ocean dynamics. A simple but very practical Eulerian forward-back-ward method was adopted to replace the most preferred leapfrog scheme as the time-differencing method for both barotropic and baroclinic modes. The forward-backward method is of second-order of accuracy, computationally efficient by requiring only one function evaluation per time step, and free of the compu-tational mode inherent in the three-level schemes. This method is superior to the leapfrog scheme in that the maximum time step of stability is twice as large as that of the leapfrog scheme in staggered meshes thus the computational efficiency could be doubled. A spatial smoothing method was introduced to control the nonlinear instability in the numerical integration. An ideal numerical experiment simulating the propa-gation of the equatorial Rossby soliton was performed to test the amplitude and phase error of this new model. The performance of this circulation model was further verified with a regional (northwest Pacific) and a quasi-global (global ocean simulation with the Arctic Ocean excluded) simulation experiments. These two numerical experiments show fairly good agreement with the observations. The maximum time step of stability in these two experiments were also investigated and compared between this model and that model which adopts the leapfrog scheme.

  6. Tests of the higher order turbulence model for atmospheric circulations (HOTMAC) at Deseret Chemical Depot

    Energy Technology Data Exchange (ETDEWEB)

    Costigan, K.R.

    1998-11-01

    Deseret Chemical Depot is one of the US Army`s storage facilities for its stockpile of chemical weapon agents. Congress has directed the Department of Defense to eliminate the aging stockpiles, which have existed since the end of World War II, and the US Army is destroying these lethal chemical munitions. Although the danger is slight, accurate predictions of the wind field in the valley are necessary for dispersion calculations in the event of an accident involving toxic chemicals at the depot. There are several small communities in Rush and Tooele valleys, including the town of Tooele, and Salt Lake City is located 65 km to the Northeast of Deseret Chemical Depot South area, at 1,300 m MSL and beyond the Oquirrh Mountains. The purpose of this report is to carry out three-dimensional numerical simulations of the atmospheric circulations in the region around Deseret Chemical Depot with the Higher Order Turbulence Model for Atmospheric Circulations (HOTMAC) and to evaluate the performance of the model. The code had been modified to assimilate local meteorological observations through the use of Newtonian nudging. The nudging scheme takes advantage of the extensive network of local observations in the valley.

  7. Computational modeling of red blood cells: A symplectic integration algorithm

    Science.gov (United States)

    Schiller, Ulf D.; Ladd, Anthony J. C.

    2010-03-01

    Red blood cells can undergo shape transformations that impact the rheological properties of blood. Computational models have to account for the deformability and red blood cells are often modeled as elastically deformable objects. We present a symplectic integration algorithm for deformable objects. The surface is represented by a set of marker points obtained by surface triangulation, along with a set of fiber vectors that describe the orientation of the material plane. The various elastic energies are formulated in terms of these variables and the equations of motion are obtained by exact differentiation of a discretized Hamiltonian. The integration algorithm preserves the Hamiltonian structure and leads to highly accurate energy conservation, hence he method is expected to be more stable than conventional finite element methods. We apply the algorithm to simulate the shape dynamics of red blood cells.

  8. Venus atmosphere simulated by a high-resolution general circulation model

    Science.gov (United States)

    Sugimoto, Norihiko

    2016-07-01

    An atmospheric general circulation model (AGCM) for Venus on the basis of AFES (AGCM For the Earth Simulator) have been developed (e.g., Sugimoto et al., 2014a) and a very high-resolution simulation is performed. The highest resolution of the model is T319L120; 960 times 480 horizontal grids (grid intervals are about 40 km) with 120 vertical layers (layer intervals are about 1 km). In the model, the atmosphere is dry and forced by the solar heating with the diurnal and semi-diurnal components. The infrared radiative process is simplified by adopting Newtonian cooling approximation. The temperature is relaxed to a prescribed horizontally uniform temperature distribution, in which a layer with almost neutral static stability observed in the Venus atmosphere presents. A fast zonal wind in a solid-body rotation is given as the initial state. Starting from this idealized superrotation, the model atmosphere reaches a quasi-equilibrium state within 1 Earth year and this state is stably maintained for more than 10 Earth years. The zonal-mean zonal flow with weak midlatitude jets has almost constant velocity of 120 m/s in latitudes between 45°S and 45°N at the cloud top levels, which agrees very well with observations. In the cloud layer, baroclinic waves develop continuously at midlatitudes and generate Rossby-type waves at the cloud top (Sugimoto et al., 2014b). At the polar region, warm polar vortex zonally surrounded by a cold latitude band (cold collar) is well reproduced (Ando et al., 2016). As for horizontal kinetic energy spectra, divergent component is broadly (k>10) larger than rotational component compared with that on Earth (Kashimura et al., in preparation). Finally, recent results for thermal tides and small-scale waves will be shown in the presentation. Sugimoto, N. et al. (2014a), Baroclinic modes in the Venus atmosphere simulated by GCM, Journal of Geophysical Research: Planets, Vol. 119, p1950-1968. Sugimoto, N. et al. (2014b), Waves in a Venus general

  9. Association between circulating white blood cell count and long-term incidence of age-related macular degeneration: the Blue Mountains Eye Study.

    Science.gov (United States)

    Shankar, Anoop; Mitchell, Paul; Rochtchina, Elena; Tan, Jennifer; Wang, Jie Jin

    2007-02-15

    Inflammatory processes are implicated in the development and progression of age-related macular degeneration (AMD). However, there are limited data on longitudinal associations between systemic markers of inflammation and AMD. The authors examined the prospective relation between the circulating white blood cell (WBC) count and early and late AMD in a population-based cohort of 3,654 participants, aged 49-97 years, in the Blue Mountains region, Australia. The main outcome of interest was the 10-year incidence of early and late AMD among individuals free from corresponding disease at the baseline (1992-1994). An elevated baseline WBC count was associated with early AMD incidence, independent of smoking and other major confounders. The multivariable relative risk comparing tertile 3 of WBC count (>6.7 x 10(9) cells/liter) with tertile 1 (circulating WBC count, a widely available marker of inflammation, and incidence of early AMD.

  10. EXPERIMENTS OF A REDUCED GRID IN LASG/IAP WORLD OCEAN GENERAL CIRCULATION MODELS (OGCMs)

    Institute of Scientific and Technical Information of China (English)

    LIU Xiying; LIU Hailong; ZHANG Xuehong; YU Rucong

    2006-01-01

    Due to the decrease in grid size associated with the convergence of meridians toward the poles in spherical coordinates, the time steps in many global climate models with finite-difference method are restricted to be unpleasantly small. To overcome the problem, a reduced grid is introduced to LASG/IAP world ocean general circulation models. The reduced grid is implemented successfully in the coarser resolutions version model L30T63 at first. Then, it is carried out in the improved version model LICOM with finer resolutions. In the experiment with model L30T63, under time step unchanged though, execution time per single model run is shortened significantly owing to the decrease of grid number and filtering execution in high latitudes. Results from additional experiments with L30T63 show that the time step of integration can be quadrupled at most in reduced grid with refinement ratio 3. In the experiment with model LICOM and with the model's original time step unchanged, the model covered area is extended to the whole globe from its original case with the grid point of North Pole considered as an isolated island and the results of experiment are shown to be acceptable.

  11. Complex mean circulation over the inner shelf south of Martha's Vineyard revealed by observations and a high-resolution model

    Science.gov (United States)

    Ganju, Neil K.; Lentz, Steven J.; Kirincich, Anthony R.; Farrar, J. Thomas

    2011-01-01

    Inner-shelf circulation is governed by the interaction between tides, baroclinic forcing, winds, waves, and frictional losses; the mean circulation ultimately governs exchange between the coast and ocean. In some cases, oscillatory tidal currents interact with bathymetric features to generate a tidally rectified flow. Recent observational and modeling efforts in an overlapping domain centered on the Martha's Vineyard Coastal Observatory (MVCO) provided an opportunity to investigate the spatial and temporal complexity of circulation on the inner shelf. ADCP and surface radar observations revealed a mean circulation pattern that was highly variable in the alongshore and cross-shore directions. Nested modeling incrementally improved representation of the mean circulation as grid resolution increased and indicated tidal rectification as the generation mechanism of a counter-clockwise gyre near the MVCO. The loss of model skill with decreasing resolution is attributed to insufficient representation of the bathymetric gradients (Δh/h), which is important for representing nonlinear interactions between currents and bathymetry. The modeled momentum balance was characterized by large spatial variability of the pressure gradient and horizontal advection terms over short distances, suggesting that observed inner-shelf momentum balances may be confounded. Given the available observational and modeling data, this work defines the spatially variable mean circulation and its formation mechanism—tidal rectification—and illustrates the importance of model resolution for resolving circulation and constituent exchange near the coast. The results of this study have implications for future observational and modeling studies near the MVCO and other inner-shelf locations with alongshore bathymetric variability.

  12. Speech therapy changes blood circulation and oxygenation in the brain and muscle: a near-infrared spectrophotometry study.

    Science.gov (United States)

    Wolf, Martin; von Bonin, Dietrich; Wolf, Ursula

    2011-01-01

    Recently it has been shown that artistic speech therapy (AST) has effects on heart rate variability. The aim of this pilot study was to investigate whether AST also affects hemodynamics and tissue oxygenation in the brain and skeletal muscle measured by near infrared spectrophotometry(NIRS). The results show that ATS has effects on important physiological parameters, i.e., it leads to a decrease in cerebral blood flow during recitation and to brain activation thereafter.

  13. Storms, hanged pirates, anemia, exsanguination: the contributions of Monro, Kellie and Abercrombie in understanding intracranial blood circulation

    Directory of Open Access Journals (Sweden)

    Pasquale De Bonis

    2014-12-01

    Full Text Available The so-called Monro-Kellie doctrine states that with an intact skull, the sum of the volume of the brain plus the cerebrospinal fluid volume plus the intracranial blood volume is constant. Therefore an increase in one should cause a reduction in one or both of the remaining two. The researcher who expressed the doctrine in such a way was indeed Harvey Cushing in 1925, during a lecture in Edinburgh. The original Monro-Kellie doctrine is the result of observations on autopsies and several animal experiments. What the original doctrine states is a dynamic explanation of the intracranial system, aimed at explaining how a pulsatile and continuous perfusion may occur in a closed-non-expandable and fully filled system. During each cardiac cycle the quantity of blood within the head must be the same: during the systole, the brain arteries dilate, and, in the mean time, a quantity of blood, equal to that which is dilating them, is passing out of the head through the veins. During the succeeding diastole, the quantity which dilated the brain arteries passes into the corresponding veins and, at the same time, as much passes from the sinuses out of the head, as enters into the head from the arteries situated between the heart and the head. Monro implicitly states that the blood coming out from the cerebral veins into the sinuses must be pulsatile and (almost synchronous with the arteries. That is deeply different from the concept of a constant content of a rigid case, as expressed by Cushing.

  14. Nourishing Yin and Promoting Blood Circulation of TCM to Treat Hemorheologic Disorder Induced by Diabetes Mellitus in Rats

    Directory of Open Access Journals (Sweden)

    Rong Xia

    2007-01-01

    Full Text Available Diabetes mellitus, DM, is commonly accompanied with various stages of hemorheologic disturbances that are the main causes of the development of chronic DM. In this study, simple Chinese material medica [yang-yin jiang-tang preparation (YYJT] was given to alloxan-induced DM rats and analyzed to compare the changes of fasting blood glucose (FBG, fasting insulin (FINS, hemorheologic parameters and insulin-like growth factor II (IGF-II before and after administration. The results suggested that YYJT can significantly downregulate FBG (P < 0.005, improve insulin resistance and beta-cell secretion (P < 0.05, decrease whole blood viscosity at low and high shear rates, gathering of blood index test (GIT and fibrinogen (FIB (P < 0.05, and enlarge the function of IGF-II (P < 0.05. We concluded that YYJT could prevent and treat hemorheologic disorder in DM rats by means of reducing glucose, improving insulin resistance and elevating IGF-II.

  15. Quantitative assessment of oscillatory components in blood circulation: classification of the effect of aging, diabetes, and acute myocardial infarction

    Science.gov (United States)

    Bernjak, Alan; Stefanovska, Aneta; Urbancic-Rovan, Vilma; Azman-Juvan, Katja

    2005-04-01

    The human cardiovascular system is a complex system with the pumping activity of the heart as the main generator of oscillations. Besides the heartbeat there are several other oscillatory components which determine its dynamics. Their nonlinear nature and a weak coupling between them both require special treatment while studying this system. A particular characteristic of the oscillatory components is their frequency fluctuations in time. Consequently, their interactions also fluctuate in time. Therefore the wavelet transform is applied to trace the oscillatory components in time, and specific quantitative measures are introduced to quantify the contribution of each of the oscillatory components involved on the time scale of up to three minutes. Oscillatory components are then analysed from signals obtained by simultaneous measurements of blood flow in the microcirculation, ECG, respiration and blood pressure. Based on quantitative evaluation of the oscillatory components related to (I) the heart beat (0.6-2Hz), (II) respiration (0.145-0.6Hz), (III) intrinsic myogenic activity (0.052-0.145Hz), (IV) sympathetic activity (0.021-0.052Hz), (V, VI) endothelial related activity (0.0095-0.021Hz, 0.005 - 0.0095 Hz), 30-minutes recording taken on 109 healthy subjects, 75 patients with diabetes, and 82 patients after acute myocardial infarction (AMI) were analysed. Classification of the effect of ageing, diabetes and AMI from blood flow signals simultaneously recorded in the skin of four extremities, the heart rate and heart rate variability from R-R intervals will be presented and discussed.

  16. The identification of blood circulation in the operation of free flap transplantation%游离皮瓣移植术中血液循环判断

    Institute of Scientific and Technical Information of China (English)

    顾加祥; 田恒; 张乃臣; 刘宏君; 潘俊博; 董佳生

    2012-01-01

    Objective To explore the significance of identifying blood circulation in the operation of free flap transplantation to a successful flap surgery. Methods Twenty - six patients who suffered from trauma and soft tissue loss in our hospital from Mar. 2007 to Dec. 2009 received free skin flap transplantation with latissimus dorsi muscle and thigh anterolatera flap. The correlation between flap flexibility, color, the color of the venous blood, and flap survival after surgery were observed. Results After surgery, it was found that the flap survival was good if the flap flexibility and the color of the flap had the same color with the donor area and the venous blood became mauve. Conclusion The identification of blood circulation in the operation of free flap transplantation is important to a successful flap surgery.%目的 探讨游离皮瓣移植术中血液循环判断对皮瓣手术成功的指导意义.方法 对2007年3月~2009年12月26例外伤后皮肤和软组织缺损的患者行游离背阔肌和股前外侧皮瓣移植,观察术中吻合血管后皮瓣的弹性、色泽,吻合处静脉血流的颜色和术后皮瓣的存活之间的关系.结果 游离皮瓣移植术中吻合血管后,如皮瓣的弹性正常、色泽逐渐转为原供区切取前色泽,静脉血流颜色转为(淡)紫红色,则皮瓣术后存活良好.结论 游离皮瓣移植术中静脉血流和皮瓣颜色等血液循环的判断对皮瓣存活有重要的参考的意义.

  17. Developing Novel Therapeutic Approaches in Small Cell Lung Carcinoma Using Genetically Engineered Mouse Models and Human Circulating Tumor Cells

    Science.gov (United States)

    2015-10-01

    Using Genetically Engineered Mouse Models and Human Circulating Tumor Cells PRINCIPAL INVESTIGATOR: Jeffrey Engelman MD PhD CONTRACTING...SUBTITLE Developiing Novel Therapeutic Approaches in Small Cell Lung 5a. CONTRACT NUMBER Carcinoma Using Genetically Engineered Mouse Models and 5b...biomarkers. 15. SUBJECT TERMS Small cell lung cancer (SCLC), Genetically engineered mouse model (GEMM), BH3 mimetic, TORC inhibitor, Apoptosis

  18. A simple model of cerebral blood flow dependence on arterial blood pressure

    CERN Document Server

    Gersten, Alexander

    2011-01-01

    It is shown that the dependence of the cerebral blood flow (CBF) on mean arterial blood pressure (MABP) can be described with a simple model having the following assumptions. Below certain MABP (denoted as MABP1) there are no autoregulatory or feedback mechanisms influencing CBF. Between MABP1 and MABP2 (MABP at which breakthrough accurs) there is a linear (on MABP) dependent feedback with a sloap depending very much on the individual considered. The classical autoregulation model with a plateau in between MABP1 and MABP2 is a particular case of this model. The model describes well the experiments performed on dogs (Harper 1966), for which the individual feedback sloap parameter varied to great extent, indicating the importance of mesurments on individuals against averaged mesurments (or measurments on diffent individuals) which superficially support the classical autoregulation. New effect of decreased CBF, while increasing MABP, was observed.

  19. Numerical modeling of supercritical CO{sub 2} natural circulation loop

    Energy Technology Data Exchange (ETDEWEB)

    Archana, V., E-mail: archanav@barc.gov.in [Homi Bhabha National Institute, Mumbai, Maharashtra 400 094 (India); Vaidya, A.M., E-mail: avaidya@barc.gov.in [Bhabha Atomic Research Centre, Mumbai, Maharashtra 400 085 (India); Vijayan, P.K., E-mail: vijayanp@barc.gov.in [Bhabha Atomic Research Centre, Mumbai, Maharashtra 400 085 (India)

    2015-11-15

    Highlights: • Supercritical CO{sub 2} natural circulation loop is modeled by in-house developed 1D and 2D axi-symmetric CFD codes. • Steady state characteristics of VHVC configuration of supercritical CO{sub 2} natural circulation loop are studied over a range of power. • Improved accuracy of predictions by 2D axi-symmetric formulation over 1D formulation is demonstrated. • The validity of correlations used in 1D model such as friction factor and heat transfer correlations is analyzed. • Simulation results shows normal, enhanced and deteriorated heat transfer regimes in supercritical CO{sub 2} natural circulation loop. - Abstract: The objective of this research project is to estimate steady state characteristics of supercritical natural circulation loop (SCNCL) using computational methodology and to compliment on-going experimental investigation of the same at the authors’ organization. For computational investigation, a couple of in-house codes are developed. At first, formulation and a corresponding computer program for the SCNCL based on conservation equations written in 1D framework is developed. Comparison of 1D code results with experimental data showed that, under some operating conditions, there is deviation between computed results and experimental data. To improve predictive capability, it was thought to model the SCNCL using conservation equations in 2D axi-symmetric framework. An existing 2D axi-symmetric code (named NAFA), which was developed and validated for supercritical fluid flow in pipes, is modified for natural circulation loop (NCL) geometry. The modified code, named NAFA-Loop, is subsequently used to compute the steady state characteristics of the SCNCL. These results are compared with experimental data. The steady state characteristics such as the variation of mass flow rate with power, velocity and temperature profiles in heater and cooler are studied using NAFA-Loop. The computed velocity and temperature fields show that the

  20. A VARIATIONAL MODEL FOR 2-D MICROPOLAR BLOOD FLOW

    Institute of Scientific and Technical Information of China (English)

    He Ji-huan

    2003-01-01

    The micropolar fluid model is an essential generalization of the well-established Navier-Stokes model in the sense that it takes into account the microstructure of the fluid.This paper is devolted to establishing a variational principle for 2-D incompressible micropolar blood flow.

  1. Volcanic forcing improves Atmosphere-Ocean Coupled General Circulation Model scaling performance

    CERN Document Server

    Vyushin, D; Havlin, S; Bunde, A; Brenner, S; Vyushin, Dmitry; Zhidkov, Igor; Havlin, Shlomo; Bunde, Armin; Brenner, Stephen

    2004-01-01

    Recent Atmosphere-Ocean Coupled General Circulation Model (AOGCM) simulations of the twentieth century climate, which account for anthropogenic and natural forcings, make it possible to study the origin of long-term temperature correlations found in the observed records. We study ensemble experiments performed with the NCAR PCM for 10 different historical scenarios, including no forcings, greenhouse gas, sulfate aerosol, ozone, solar, volcanic forcing and various combinations, such as it natural, anthropogenic and all forcings. We compare the scaling exponents characterizing the long-term correlations of the observed and simulated model data for 16 representative land stations and 16 sites in the Atlantic Ocean for these scenarios. We find that inclusion of volcanic forcing in the AOGCM considerably improves the PCM scaling behavior. The scenarios containing volcanic forcing are able to reproduce quite well the observed scaling exponents for the land with exponents around 0.65 independent of the station dista...

  2. Assimilation of drifter observations in primitive equation models of midlatitude ocean circulation

    Science.gov (United States)

    Özgökmen, Tamay M.; Molcard, Anne; Chin, Toshio M.; Piterbarg, Leonid I.; Griffa, Annalisa

    2003-07-01

    Motivated by increases in the realism of OGCMs and the number of drifting buoys in the ocean observing system, a new Lagrangian assimilation technique is implemented in an idealized, reduced-gravity configuration of the layered primitive equation model MICOM. Using an extensive set of twin experiments, the effectiveness of the Lagrangian observation operator and of a dynamical balancing technique for corrected model variables, which is based on geostrophy and mass conservation, are explored in comparison to a conventional Pseudo-Lagrangian observation operator and an implementation of the Kalman filter method. The results clearly illustrate that the Lagrangian observation operator is superior to the Pseudo-Lagrangian in the parameter range that is relevant for typical oceanic drifter observations, and that the simple dynamical balancing technique works well for midlatitude ocean circulation.

  3. Intercomparison and interpretation of surface energy fluxes in atmospheric general circulation models

    Science.gov (United States)

    Randall, D. A.; Cess, R. D.; Blanchet, J. P.; Boer, G. J.; Dazlich, D. A.; Del Genio, A. D.; Deque, M.; Dymnikov, V.; Galin, V.; Ghan, S. J.

    1992-01-01

    Responses of the surface energy budgets and hydrologic cycles of 19 atmospheric general circulation models to an imposed, globally uniform sea surface temperature perturbation of 4 K were analyzed. The responses of the simulated surface energy budgets are extremely diverse and are closely linked to the responses of the simulated hydrologic cycles. The response of the net surface energy flux is not controlled by cloud effects; instead, it is determined primarily by the response of the latent heat flux. The prescribed warming of the oceans leads to major increases in the atmospheric water vapor content and the rates of evaporation and precipitation. The increased water vapor amount drastically increases the downwelling IR radiation at the earth's surface, but the amount of the change varies dramatically from one model to another.

  4. Characteristics modeling for supercritical circulating fluidized bed boiler working in oxy-combustion technology

    Science.gov (United States)

    Balicki, Adrian; Bartela, Łukasz

    2014-06-01

    Among the technologies which allow to reduce greenhouse gas emission, mainly carbon dioxide, special attention deserves the idea of `zeroemission' technology based on boilers working in oxy-combustion technology. In the paper the results of analyses of the influence of changing two quantities, namely oxygen share in oxidant produced in the air separation unit, and oxygen share in oxidant supplied to the furnace chamber on the selected characteristics of a steam boiler including the degree of exhaust gas recirculation, boiler efficiency and adiabatic flame temperature, was examined. Due to the possibility of the integration of boiler model with carbon dioxide capture, separation and storage installation, the subject of the analysis was also to determine composition of the flue gas at the outlet of a moisture condensation installation. Required calculations were made using a model of a supercritical circulating fluidized bed boiler working in oxy-combustion technology, which was built in a commercial software and in-house codes.

  5. Locally-orthogonal, unstructured grid-generation for general circulation modelling on the sphere

    CERN Document Server

    Engwirda, Darren

    2016-01-01

    An algorithm for the generation of non-uniform, locally-orthogonal staggered unstructured grids on spheroidal geometries is described. This technique is designed to generate high-quality staggered Voronoi/Delaunay dual meshes appropriate for general circulation modelling on the sphere, including applications to atmospheric simulation, ocean-modelling and numerical weather predication. Using a recently developed Frontal-Delaunay refinement technique, a method for the construction of guaranteed-quality, unstructured spheroidal Delaunay triangulations is introduced. A locally-orthogonal polygonal grid, derived from the associated Voronoi diagram, is computed as the staggered dual. The initial staggered Voronoi/Delaunay tessellation is iteratively improved through hill-climbing optimisation techniques. It is shown that this approach typically produces grids with very high element quality and smooth grading characteristics, while imposing relatively low computational expense. Initial results are presented for a se...

  6. Effects of Southern Hemisphere Wind Changes on the Meridional Overturning Circulation in Ocean Models.

    Science.gov (United States)

    Gent, Peter R

    2016-01-01

    Observations show that the Southern Hemisphere zonal wind stress maximum has increased significantly over the past 30 years. Eddy-resolving ocean models show that the resulting increase in the Southern Ocean mean flow meridional overturning circulation (MOC) is partially compensated by an increase in the eddy MOC. This effect can be reproduced in the non-eddy-resolving ocean component of a climate model, providing the eddy parameterization coefficient is variable and not a constant. If the coefficient is a constant, then the Southern Ocean mean MOC change is balanced by an unrealistically large change in the Atlantic Ocean MOC. Southern Ocean eddy compensation means that Southern Hemisphere winds cannot be the dominant mechanism driving midlatitude North Atlantic MOC variability.

  7. Blood

    Science.gov (United States)

    ... Also, blood is either Rh-positive or Rh-negative. So if you have type A blood, it's either A positive or A negative. Which type you are is important if you need a blood transfusion. And your Rh factor could be important ...

  8. The water cycle in the general circulation model of the martian atmosphere

    Science.gov (United States)

    Shaposhnikov, D. S.; Rodin, A. V.; Medvedev, A. S.

    2016-03-01

    Within the numerical general-circulation model of the Martian atmosphere MAOAM (Martian Atmosphere: Observation and Modeling), we have developed the water cycle block, which is an essential component of modern general circulation models of the Martian atmosphere. The MAOAM model has a spectral dynamic core and successfully predicts the temperature regime on Mars through the use of physical parameterizations typical of both terrestrial and Martian models. We have achieved stable computation for three Martian years, while maintaining a conservative advection scheme taking into account the water-ice phase transitions, water exchange between the atmosphere and surface, and corrections for the vertical velocities of ice particles due to sedimentation. The studies show a strong dependence of the amount of water that is actively involved in the water cycle on the initial data, model temperatures, and the mechanism of water exchange between the atmosphere and the surface. The general pattern and seasonal asymmetry of the water cycle depends on the size of ice particles, the albedo, and the thermal inertia of the planet's surface. One of the modeling tasks, which results from a comparison of the model data with those of the TES experiment on board Mars Global Surveyor, is the increase in the total mass of water vapor in the model in the aphelion season and decrease in the mass of water ice clouds at the poles. The surface evaporation scheme, which takes into account the turbulent rise of water vapor, on the one hand, leads to the most complete evaporation of ice from the surface in the summer season in the northern hemisphere and, on the other hand, supersaturates the atmosphere with ice due to the vigorous evaporation, which leads to worse consistency between the amount of the precipitated atmospheric ice and the experimental data. The full evaporation of ice from the surface increases the model sensitivity to the size of the polar cap; therefore, the increase in the

  9. The Finite Element Sea Ice-Ocean Model (FESOM v.1.4: formulation of an ocean general circulation model

    Directory of Open Access Journals (Sweden)

    Q. Wang

    2014-04-01

    Full Text Available The Finite Element Sea Ice-Ocean Model (FESOM is the first global ocean general circulation model based on unstructured-mesh methods that has been developed for the purpose of climate research. The advantage of unstructured-mesh models is their flexible multi-resolution modelling functionality. In this study, an overview of the main features of FESOM will be given; based on sensitivity experiments a number of specific parameter choices will be explained; and directions of future developments will be outlined. It is argued that FESOM is sufficiently mature to explore the benefits of multi-resolution climate modelling and that its applications will provide information useful for the advancement of climate modelling on unstructured meshes.

  10. Spring-network-based model of a red blood cell for simulating mesoscopic blood flow.

    Science.gov (United States)

    Nakamura, Masanori; Bessho, Sadao; Wada, Shigeo

    2013-01-01

    We developed a mechanical model of a red blood cell (RBC) that is capable of expressing its characteristic behaviors in shear flows. The RBC was modeled as a closed shell membrane consisting of spring networks in the framework of the energy minimum concept. The fluid forces acting on RBCs were modeled from Newton's viscosity law and the conservation of momentum. In a steady shear flow, the RBC model exhibited various behaviors, depending on the shear rate; it tumbled, tank-treaded, or both. The transition from tumbling to tank-treading occurred at a shear rate of 20 s( - 1). The simulation of an RBC in steady and unsteady parallel shear flows (Couette flows) showed that the deformation parameters of the RBC were consistent with experimental results. The RBC in Poiseuille flow migrated radially towards the central axis of the flow channel. Axial migration became faster with an increase in the viscosity of the media, qualitatively consistent with experimental results. These results demonstrate that the proposed model satisfies the essential conditions for simulating RBC behavior in blood flow. Finally, a large-scale RBC flow simulation was implemented to show the capability of the proposed model for analyzing the mesoscopic nature of blood flow.

  11. Circulating thrombopoietin levels in normal healthy blood donors and in aplastic anemia patients in relation to disease severity

    Directory of Open Access Journals (Sweden)

    Abhay Singh

    2015-01-01

    Full Text Available Background: Thrombopoietin (TPO is the key hematopoietic growth factor regulating the production of platelets from bone marrow megakaryocytes and maintaining platelet hemostasis. This study was done to find any relationship between the levels of thrombopoietin and the severity of disease in patients with aplastic anemia. Materials and Methods: Serum samples were collected from 52 patients with a confirmed diagnosis of aplastic anemia and 45 normal healthy blood donors of both sexes over a period of 2 years, and TPO was estimated by using commercially available TPO-specific-enzyme-linked immunosorbent assay. Results: The median TPO level of 1190 pg/ml (range 625-7651 pg/ml in aplastic anemia patients was significantly higher than the median TPO level of 121.1 pg/ml (81.25-237.7 pg/ml in normal healthy blood donors (P = 0.000. No significant difference was observed in TPO levels of male and female patients (P = 0.453. The median TPO concentrations observed in very severe aplastic anemia, severe aplastic anemia, and nonsevere aplastic anemia were 2765 pg/ml (range 625-6451 pg/ml, 1190 pg/ml (range 672.1-7651 pg/ml, and 1111.5 pg/ml (range 761.1-2289.2 pg/ml, respectively. TPO in patients of very severe aplastic anemia was significantly higher than patients of nonsevere aplastic anemia (P = 0.043, with no significant relation among rest of the groups. Discussion: TPO levels in aplastic anemia patients were significantly higher than in healthy blood donors; however, in aplastic anemia patients TPO levels were significantly higher only in patients with very severe disease.

  12. Total kinetic energy in four global eddying ocean circulation models and over 5000 current meter records

    KAUST Repository

    Scott, Robert B.

    2010-01-01

    We compare the total kinetic energy (TKE) in four global eddying ocean circulation simulations with a global dataset of over 5000, quality controlled, moored current meter records. At individual mooring sites, there was considerable scatter between models and observations that was greater than estimated statistical uncertainty. Averaging over all current meter records in various depth ranges, all four models had mean TKE within a factor of two of observations above 3500. m, and within a factor of three below 3500. m. With the exception of observations between 20 and 100. m, the models tended to straddle the observations. However, individual models had clear biases. The free running (no data assimilation) model biases were largest below 2000. m. Idealized simulations revealed that the parameterized bottom boundary layer tidal currents were not likely the source of the problem, but that reducing quadratic bottom drag coefficient may improve the fit with deep observations. Data assimilation clearly improved the model-observation comparison, especially below 2000. m, despite assimilated data existing mostly above this depth and only south of 47°N. Different diagnostics revealed different aspects of the comparison, though in general the models appeared to be in an eddying-regime with TKE that compared reasonably well with observations. © 2010 Elsevier Ltd.

  13. Low-level jets in the NASA Ames Mars general circulation model

    Science.gov (United States)

    Joshi, M. M.; Haberle, R. M.; Barnes, J. R.; Murphy, J. R.; Schaeffer, J.

    1997-03-01

    Previous simulations of the Martian atmosphere have shown how topography acts to confine the low-level Hadley cell flow into intense jets on the eastern flanks of Tharsis and Syrtis Major. We now conduct detailed studies of these jets using the NASA Ames Mars general circulation model (MGCM). The structure of the flow is found to be sensitive to local topography as well as large-scale diabatic heating patterns, consistent with terrestrial studies, and MGCM studies carried out with simplified topography. The summer subtropical zonal winds associated with the Hadley circulation also form spatially confined intense jet cores. Diurnal variations in heating affect jet structure in three distinct ways. Global tides interact with the jets, resulting in effects such as the two reinforcing each other at the summer subtropics near midday, leading to high winds and surface stresses at this time. Slope winds act to change the character of the jets during the course of a day, especially at Syrtis Major and the Hellas basin, where slopes are large. Vertical mixing acts to decrease low-level winds during the late afternoon. The sensitivity of the results to atmospheric dust loading is examined. We finally show how a decrease in boundary layer height due to dust loading actually augments mid-afternoon jet strength near the surface. The resulting increase in maximum surface stress indicates that this is a positive feedback to dust lifting.

  14. Glacial marine carbon cycle sensitivities to Atlantic ocean circulation reorganization by coupled climate model simulations

    Directory of Open Access Journals (Sweden)

    M. O. Chikamoto

    2011-04-01

    Full Text Available A series of Last Glacial Maximum (LGM marine carbon cycle sensitivity experiments is conducted to test the effect of different physical processes, as simulated by two atmosphere-ocean general circulation model (AOGCM experiments, on the atmospheric pCO2. One AOGCM solution exhibits an increase in North Atlantic Deep Water (NADW formation, whereas the other mimics an increase in Antarctic Bottom Water (AABW associated with a weaker NADW. Due to enhanced gas solubility associated with lower sea surface temperature, both experiments generate a reduction of atmospheric pCO2 by about 20–23 ppm. However, neither a weakening of NADW nor an increase of AABW formation causes a large atmospheric pCO2 change. A marked enhancement in AABW formation is required to represent the reconstructed vertical gradient of dissolved inorganic carbon (DIC during LGM conditions. The efficiency of Southern Ocean nutrient utilization reduces in response to an enhanced AABW formation, which counteracts the circulation-induced ocean carbon uptake.

  15. Climate Dynamics and Global Change: Temperature, Precipitation, and Circulation in GFDL Aqua-Planet Model

    Science.gov (United States)

    Dinh, T.; Fueglistaler, S.

    2015-12-01

    Numerical experiments are carried out using the GFDL General Circulation Model to assess climate sensitivity associated with CO2 increase and surface warming. This work is motivated by the calculation by Cess and Potter (1988, JGR), who proposed that surface temperature perturbations may be used as a surrogate for climate change induced by CO2 increase.We compare climatic changes due to CO2 increase in slab-ocean simulations with changes forced by surface warming in prescribed-surface-temperature simulations with fixed CO2 (Cess-type experiments). We found that slab-ocean and Cess-type experiments give the same rates of change per degree surface warming for the global atmosphere temperature and circulation strength. However, the global precipitation increases almost twice as slowly in slab-ocean runs (1.5%/K) when compared to Cess-type runs (2.8%/K). Therefore, we caution that Cess-type experiments may not be suitable for studying global precipitation change under climate change.

  16. Seasonal sensitivity of the eddy-driven jet to tropospheric heating in an idealized atmospheric general circulation model

    Science.gov (United States)

    McGraw, Marie C.

    A dry dynamical core is used to investigate the seasonal sensitivity of the circulation to two idealized thermal forcings--a tropical upper tropospheric forcing, and a polar lower tropospheric forcing. The circulation is modified using a set of perpetual simulations to simulate each month of the year, while the thermal forcings are held constant. The circu- lation responses to tropical warming and polar warming are studied separately, and then the response to the simultaneously applied forcings is analyzed. Finally, the seasonality of the internal variability of the circulation is explored as a possible mechanism to explain the seasonality of the responses. The primary results of these experiments are: 1) There is a seasonal sensitivity in the circulation response to both the tropical and polar forcings. 2) The jet position response to each forcing is greatest in the transition seasons, and the jet speed response exhibits a seasonal sensitivity to both forcings although the seasonal sensi- tivities are not the same. 3) The circulation response is nonlinear in the transition seasons, but approximately linear in the summer and winter months. 4) The internal variability of the unforced circulation exhibits a seasonal sensitivity that may partly explain the seasonal sensitivity of the forced response. The seasonality of the internal variability of daily MERRA reanalysis data is compared to that of the model, demonstrating that the broad conclusions drawn from this idealized modeling study may be useful for understanding the jet response to anthropogenic forcing.

  17. Distal Pedicle Flap Blood Circulation Features and Clinical Signiifcance%远端蒂皮瓣的血液循环特征及临床意义

    Institute of Scientific and Technical Information of China (English)

    高晓光

    2016-01-01

    Objective To explore the distally based flap.Methods The clinical data of 30 cases of patients with distal pedicle flap, fresh limb specimen of forearm and leg, the characteristics and signiifcance of blood circulation in two aspects of the driven vein blood flow structure and hemodynamics.Results The distally based lfap blood supply is divided into four types: body is organized vascular network (cluster), muscle interstitial fascia, direct skin blood vessel, well-known blood vessel, there was no reverse flow, more fit with physiological.ConclusionIt is a prerequisite for the survival of the lfap to observe whether the venous relfux is smooth, Superifcial venous blood can be introduced into the lfap, from shallow to deep will increase the return load, increase the survival rate of skin lfap.%目的:探究远端蒂皮瓣的血液循环特征及临床意义。方法收集30例行远端蒂皮瓣术患者的临床资料,取前臂与小腿新鲜肢体标本,从动静脉血流构筑与血流动力学两方面探究血液循环特征与意义。结果将远端蒂皮瓣供血方式分为四种:体被组织血管网(丛)、肌间隙筋膜穿血管、直接皮肤血管、知名血管,均没有出现逆向血流,与生理性更贴合。结论观察静脉回流是否顺畅是决定皮瓣能否成活的前提,蒂部浅静脉能将远端静脉血导入皮瓣内,由浅到深将回流负荷加重,增加了皮瓣成活率。

  18. A novel transgenic zebrafish model for blood-brain and blood-retinal barrier development

    Directory of Open Access Journals (Sweden)

    Sugimoto Masahiko

    2010-07-01

    Full Text Available Abstract Background Development and maintenance of the blood-brain and blood-retinal barrier is critical for the homeostasis of brain and retinal tissue. Despite decades of research our knowledge of the formation and maintenance of the blood-brain (BBB and blood-retinal (BRB barrier is very limited. We have established an in vivo model to study the development and maintenance of these barriers by generating a transgenic zebrafish line that expresses a vitamin D-binding protein fused with enhanced green fluorescent protein (DBP-EGFP in blood plasma, as an endogenous tracer. Results The temporal establishment of the BBB and BRB was examined using this transgenic line and the results were compared with that obtained by injection of fluorescent dyes into the sinus venosus of embryos at various stages of development. We also examined the expression of claudin-5, a component of tight junctions during the first 4 days of development. We observed that the BBB of zebrafish starts to develop by 3 dpf, with expression of claudin-5 in the central arteries preceding it at 2 dpf. The hyaloid vasculature in the zebrafish retina develops a barrier function at 3 dpf, which endows the zebrafish with unique advantages for studying the BRB. Conclusion Zebrafish embryos develop BBB and BRB function simultaneously by 3 dpf, which is regulated by tight junction proteins. The Tg(l-fabp:DBP-EGFP zebrafish will have great advantages in studying development and maintenance of the blood-neural barrier, which is a new application for the widely used vertebrate model.

  19. 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.

  20. Functional state of blood circulation and neuromuscular system of the lower limb of patients with congenital pseudarthrosis of the tibia after consolidation of the nonunion

    Directory of Open Access Journals (Sweden)

    Александр Павлович Поздеев

    2015-12-01

    Full Text Available The aim of this study was to evaluate the clinical and functional state of the neuromuscular system and the blood supply to the lower limbs of children with congenital pseudarthrosis of the tibia (CPT after consolidation. Material and Methods. A total of 100 patients with CPT were analyzed. We performed a clinical examination of patients, panoramic X-ray of the lower extremities, electroneuromyogram, and reovasography. Results and Conclusions. The primary complaints of patients with CPT after the consolidation of the non-union were lameness, deformations of lower extremities, and pain in the local joints. The electromyoneuromyogram data of the lower limbs of patients with CPT exhibited a decrease of the contractility of the muscles of the lower limbs, and neuropathy of the peroneal nerves of both lower limbs. The reovasography data of the lower limbs of patients with CPT displayed improvement in blood circulation in the lower extremities after the consolidation of the tibia. These data promote the current methods of treatment of patients with CPT; however, the temperature, degree of limb lengthening, and deformity correction should be considered in the future.

  1. The annual pressure cycle on Mars: Results from the LMD Martian atmospheric general circulation model

    Science.gov (United States)

    Hourdin, Frederic; Forget, Francois; Talagrand, O.

    1993-01-01

    We have been developing a General Circulation Model (GCM) of the martian atmosphere since 1989. The model has been described rather extensively elsewhere and only the main characteristics are given here. The dynamical part of the model, adapted from the LMD terrestrial climate model, is based on a finite-difference formulation of the classical 'primitive equations of meteorology.' The radiative transfer code includes absorption and emission by CO2 (carefully validated by comparison to line-by-line calculations) and dust in the thermal range and absorption and scattering by dust in the visible range. Other physical parameterizations are included: modeling of vertical turbulent mixing, dry convective adjustment (in order to prevent vertical unstable temperature profiles), and a multilayer model of the thermal conduction in the soil. Finally, the condensation-sublimation of CO2 is introduced through specification of a pressure-dependent condensation temperature. The atmospheric and surface temperatures are prevented from falling below this critical temperature by condensation and direct precipitation onto the surface of atmospheric CO2. The only prespecified spatial fields are the surface thermal inertia, albedo, and topography.

  2. Bivariate spatial analysis of temperature and precipitation from general circulation models and observation proxies

    KAUST Repository

    Philbin, R.

    2015-05-22

    This study validates the near-surface temperature and precipitation output from decadal runs of eight atmospheric ocean general circulation models (AOGCMs) against observational proxy data from the National Centers for Environmental Prediction/National Center for Atmospheric Research (NCEP/NCAR) reanalysis temperatures and Global Precipitation Climatology Project (GPCP) precipitation data. We model the joint distribution of these two fields with a parsimonious bivariate Matérn spatial covariance model, accounting for the two fields\\' spatial cross-correlation as well as their own smoothnesses. We fit output from each AOGCM (30-year seasonal averages from 1981 to 2010) to a statistical model on each of 21 land regions. Both variance and smoothness values agree for both fields over all latitude bands except southern mid-latitudes. Our results imply that temperature fields have smaller smoothness coefficients than precipitation fields, while both have decreasing smoothness coefficients with increasing latitude. Models predict fields with smaller smoothness coefficients than observational proxy data for the tropics. The estimated spatial cross-correlations of these two fields, however, are quite different for most GCMs in mid-latitudes. Model correlation estimates agree well with those for observational proxy data for Australia, at high northern latitudes across North America, Europe and Asia, as well as across the Sahara, India, and Southeast Asia, but elsewhere, little consistent agreement exists.

  3. Modeling of NO and N{sub 2}O emissions from biomass circulating fluidized bed combustors

    Energy Technology Data Exchange (ETDEWEB)

    Liu, H.; Gibbs, B.M. [Leeds Univ., Leeds (United Kingdom). Dept. of Fuel and Energy

    2002-07-01

    In order to correctly model biomass combustion in a circulating fluidized bed (CFB) combustor, it is necessary to examine the four main stages in the combustion of biomass particles. These include drying, devolatilization, volatile combustion and char combustion in a CFB combustor. This paper presents a newly developed model for nitric oxide (NO) and nitrous oxide (N{sub 2}O) emissions from biomass-fired CFB combustors. A typical woody biomass of pinewood chips was selected for the model parameters. The drying and devolatilization of biomass particles was modeled with limited rates according to woody biomass fuels. The partition of fuel nitrogen between volatiles and char was chosen for pinewood based on available data from literature. It was assumed that the volatile nitrogen was composed of ammonia (NH{sub 3}), hydrogen cyanide (HCN) and nitrogen (N{sub 2}). The model included 25 chemical reactions, of which 20 belonged to global fuel-nitrogen reaction kinetics. A 12 MW CFB boiler was used to apply the model. Results were compared with experimental values as well as data from literature. The reaction between NO and char was found to be the key reaction that determines NO emissions. The catalytic effect of bed materials on the oxidation of NH{sub 3} and the the homogeneous reaction of NH{sub 3} with nitric oxide was also significant. 25 refs., 2 tabs., 5 figs.

  4. Experimental and Analytical Modeling of Natural Circulation and Forced Circulation BWRs : Thermal-Hydraulic, Core-Wide, and Regional Stability Phenomena

    OpenAIRE

    2006-01-01

    Currently, 434 nuclear power plants are in operation worldwide. 21% of them are known as Boiling Water Reactors (BWRs). These BWRs have pumps that cool their reactor cores (the forced circulation BWRs). In the design of new BWRs, ways to cool the core by a natural circulation flow, without pumps, also called natural circulation BWRs, are being considered. A possible disadvantage of natural circulation BWRs might be their susceptibility to instabilities, which could then lead to both flow and ...

  5. Thrust Removal Scheme for the FAST-MAC Circulation Control Model Tested in the National Transonic Facility

    Science.gov (United States)

    Chan, David T.; Milholen, William E., II; Jones, Gregory S.; Goodliff, Scott L.

    2014-01-01

    A second wind tunnel test of the FAST-MAC circulation control semi-span model was recently completed in the National Transonic Facility at the NASA Langley Research Center. The model allowed independent control of four circulation control plenums producing a high momentum jet from a blowing slot near the wing trailing edge that was directed over a 15% chord simple-hinged flap. The model was configured for transonic testing of the cruise configuration with 0deg flap deflection to determine the potential for drag reduction with the circulation control blowing. Encouraging results from analysis of wing surface pressures suggested that the circulation control blowing was effective in reducing the transonic drag on the configuration, however this could not be quantified until the thrust generated by the blowing slot was correctly removed from the force and moment balance data. This paper will present the thrust removal methodology used for the FAST-MAC circulation control model and describe the experimental measurements and techniques used to develop the methodology. A discussion on the impact to the force and moment data as a result of removing the thrust from the blowing slot will also be presented for the cruise configuration, where at some Mach and Reynolds number conditions, the thrust-removed corrected data showed that a drag reduction was realized as a consequence of the blowing.

  6. A memory-based model for blood viscosity

    Science.gov (United States)

    Ionescu, Clara M.

    2017-04-01

    This paper presents a comparison between existing models for non-Newtonian fluid viscosity as a function of shear rate variations. A novel model is introduced whose parameters are linked to physiological phenomena in the blood. The end use of such models is to predict changes in viscosity to adapt the speed of a nanorobot device for targeted drug delivery purposes. Simulation results show the agreement between the proposed model and available models from literature. A laboratory scale validation of the proposed model for a fluid mimicking non-Newtonian properties has been performed. Conceptual perspectives are also given in this work.

  7. Blood flow mechanics and oxygen transport and delivery in the retinal microcirculation: multiscale mathematical modeling and numerical simulation.

    Science.gov (United States)

    Causin, Paola; Guidoboni, Giovanna; Malgaroli, Francesca; Sacco, Riccardo; Harris, Alon

    2016-06-01

    The scientific community continues to accrue evidence that blood flow alterations and ischemic conditions in the retina play an important role in the pathogenesis of ocular diseases. Many factors influence retinal hemodynamics and tissue oxygenation, including blood pressure, blood rheology, oxygen arterial permeability and tissue metabolic demand. Since the influence of these factors on the retinal circulation is difficult to isolate in vivo, we propose here a novel mathematical and computational model describing the coupling between blood flow mechanics and oxygen ([Formula: see text]) transport in the retina. Albeit in a simplified manner, the model accounts for the three-dimensional anatomical structure of the retina, consisting in a layered tissue nourished by an arteriolar/venular network laying on the surface proximal to the vitreous. Capillary plexi, originating from terminal arterioles and converging into smaller venules, are embedded in two distinct tissue layers. Arteriolar and venular networks are represented by fractal trees, whereas capillary plexi are represented using a simplified lumped description. In the model, [Formula: see text] is transported along the vasculature and delivered to the tissue at a rate that depends on the metabolic demand of the various tissue layers. First, the model is validated against available experimental results to identify baseline conditions. Then, a sensitivity analysis is performed to quantify the influence of blood pressure, blood rheology, oxygen arterial permeability and tissue oxygen demand on the [Formula: see text] distribution within the blood vessels and in the tissue. This analysis shows that: (1) systemic arterial blood pressure has a strong influence on the [Formula: see text] profiles in both blood and tissue; (2) plasma viscosity and metabolic consumption rates have a strong influence on the [Formula: see text] tension at the level of the retinal ganglion cells; and (3) arterial [Formula: see text

  8. Dense water formation and BiOS-induced variability in the Adriatic Sea simulated using an ocean regional circulation model

    Science.gov (United States)

    Dunić, Natalija; Vilibić, Ivica; Šepić, Jadranka; Somot, Samuel; Sevault, Florence

    2016-08-01

    A performance analysis of the NEMOMED8 ocean regional circulation model was undertaken for the Adriatic Sea during the period of 1961-2012, focusing on two mechanisms, dense water formation (DWF) and the Adriatic-Ionian Bimodal Oscillating System (BiOS), which drive interannual and decadal variability in the basin. The model was verified based on sea surface temperature and sea surface height satellite measurements and long-term in situ observations from several key areas. The model qualitatively reproduces basin-scale processes: thermohaline-driven cyclonic circulation and freshwater surface outflow along the western Adriatic coast, dense water dynamics, and the inflow of Ionian and Levantine waters to the Adriatic. Positive temperature and salinity biases are reported; the latter are particularly large along the eastern part of the basin, presumably because of the inappropriate introduction of eastern Adriatic rivers into the model. The highest warm temperature biases in the vertical direction were found in dense-water-collecting depressions in the Adriatic, indicating either an inappropriate quantification of DWF processes or temperature overestimation of modelled dense water. The decadal variability in the thermohaline properties is reproduced better than interannual variability, which is considerably underestimated. The DWF rates are qualitatively well reproduced by the model, being larger when preconditioned by higher basin-wide salinities. Anticyclonic circulation in the northern Ionian Sea was modelled only during the Eastern Mediterranean Transient. No other reversals of circulation that could be linked to BiOS-driven changes were modelled.

  9. Impact of boundary regions on the interior circulation of the California Current System in a regional modeling framework

    Science.gov (United States)

    Veneziani, M.; Edwards, C.; Moore, A.

    2008-12-01

    We use the Regional Ocean Modeling System (ROMS) to model the circulation of the California Current System (CCS) using ECCO-GODAE products to force the model at the open boundaries of the domain. We investigate the impact that lateral boundary forcing (and the boundary region in general) has on particular metrics of the interior circulation by adopting both an adjoint model and a traditional sensitivity approach. Adjoint methods are naturally suited to sensitivity studies as they provide the direct dependencies of circulation metrics on uncertainties of the model initial conditions, surface and lateral external forcing, and model parameters, but their results are only valid within the time scale during which the linearity assumption underlying adjoint models can be considered to hold. More traditional sensitivity studies must be conducted to investigate longer time scales. We describe the adjoint model results for two metrics that represent the upwelling processes of the Central California region and the mean sea level field of the coastal circulation, respectively. The spatial distribution of the adjoint sensitivity fields allows us to quantify the contribution of the boundary regions over a biweekly time scale. We investigate longer time scales by adopting two methods: 1) apply different ECCO products at the open boundaries and evaluate mean stratification changes in the CalCOFI coastal region; 2) release passive tracers at the boundaries and calculate ventilation time scales and pathways from the boundary areas to the CCS interior.

  10. Evaluation of rainfall simulations over West Africa in dynamically downscaled CMIP5 global circulation models

    Science.gov (United States)

    Akinsanola, A. A.; Ajayi, V. O.; Adejare, A. T.; Adeyeri, O. E.; Gbode, I. E.; Ogunjobi, K. O.; Nikulin, G.; Abolude, A. T.

    2017-03-01

    This study presents evaluation of the ability of Rossby Centre Regional Climate Model (RCA4) driven by nine global circulation models (GCMs), to skilfully reproduce the key features of rainfall climatology over West Africa for the period of 1980-2005. The seasonal climatology and annual cycle of the RCA4 simulations were assessed over three homogenous subregions of West Africa (Guinea coast, Savannah, and Sahel) and evaluated using observed precipitation data from the Global Precipitation Climatology Project (GPCP). Furthermore, the model output was evaluated using a wide range of statistical measures. The interseasonal and interannual variability of the RCA4 were further assessed over the subregions and the whole of the West Africa domain. Results indicate that the RCA4 captures the spatial and interseasonal rainfall pattern adequately but exhibits a weak performance over the Guinea coast. Findings from the interannual rainfall variability indicate that the model performance is better over the larger West Africa domain than the subregions. The largest difference across the RCA4 simulated annual rainfall was found in the Sahel. Result from the Mann-Kendall test showed no significant trend for the 1980-2005 period in annual rainfall either in GPCP observation data or in the model simulations over West Africa. In many aspects, the RCA4 simulation driven by the HadGEM2-ES perform best over the region. The use of the multimodel ensemble mean has resulted to the improved representation of rainfall characteristics over the study domain.

  11. Global environmental effects of impact-generated aerosols: Results from a general circulation model, revision 1

    Science.gov (United States)

    Covey, Curt; Ghan, Steven J.; Walton, John J.; Weissman, Paul R.

    1989-01-01

    Interception of sunlight by the high altitude worldwide dust cloud generated by impact of a large asteroid or comet would lead to substantial land surface cooling, according to our three-dimensional atmospheric general circulation model (GCM). This result is qualitatively similar to conclusions drawn from an earlier study that employed a one-dimensional atmospheric model, but in the GCM simulation the heat capacity of the oceans substantially mitigates land surface cooling, an effect that one-dimensional models cannot quantify. On the other hand, the low heat capacity of the GCM's land surface allows temperatures to drop more rapidly in the initial stage of cooling than in the one-dimensional model study. These two differences between three-dimensional and one-dimensional model simulations were noted previously in studies of nuclear winter; GCM-simulated climatic changes in the Alvarez-inspired scenario of asteroid/comet winter, however, are more severe than in nuclear winter because the assumed aerosol amount is large enough to intercept all sunlight falling on earth. Impacts of smaller objects could also lead to dramatic, though less severe, climatic changes, according to our GCM. Our conclusion is that it is difficult to imagine an asteroid or comet impact leading to anything approaching complete global freezing, but quite reasonable to assume that impacts at the Alvarez level, or even smaller, dramatically alter the climate in at least a patchy sense.

  12. Loss of bone marrow adrenergic beta 1 and 2 receptors modifies transcriptional networks, reduces circulating inflammatory factors, and regulates blood pressure.

    Science.gov (United States)

    Ahmari, Niousha; Schmidt, Jordan T; Krane, Gregory A; Malphurs, Wendi; Cunningham, Bruce E; Owen, Jennifer L; Martyniuk, Christopher J; Zubcevic, Jasenka

    2016-07-01

    Hypertension (HTN) is a prevalent condition with complex etiology and pathophysiology. Evidence exists of significant communication between the nervous system and the immune system (IS), and there appears to be a direct role for inflammatory bone marrow (BM) cells in the pathophysiology of hypertension. However, the molecular and neural mechanisms underlying this interaction have not been characterized. Here, we transplanted whole BM cells from the beta 1 and 2 adrenergic receptor (AdrB1(tm1Bkk)AdrB2(tm1Bkk)/J) knockout (KO) mice into near lethally irradiated C57BL/6J mice to generate a BM AdrB1.B2 KO chimera. This allowed us to evaluate the role of the BM beta 1 and beta 2 adrenergic receptors in mediating BM IS homeostasis and regulating blood pressure (BP) in an otherwise intact physiological setting. Fluorescence-activated cell sorting demonstrated that a decrease in systolic and mean BP in the AdrB1.B2 KO chimera is associated with a decrease in circulating inflammatory T cells, macrophage/monocytes, and neutrophils. Transcriptomics in the BM identified 7,419 differentially expressed transcripts between the C57 and AdrB1.B2 KO chimera. Pathway analysis revealed differentially expressed transcripts related to several cell processes in the BM of C57 compared with AdrB1.B2 KO chimera, including processes related to immunity (e.g., T-cell activation, T-cell recruitment, cytokine production, leukocyte migration and function), the cardiovascular system (e.g., blood vessel development, peripheral nerve blood flow), and the brain (e.g., central nervous system development, neurite development) among others. This study generates new insight into the molecular events that underlie the interaction between the sympathetic drive and IS in modulation of BP.

  13. 活血化瘀法治疗类风湿性关节炎的疗效观察%Therapeutic Effect of Promoting Blood Circulation and Removing Blood Stasis on Rheumatoid Arthritis

    Institute of Scientific and Technical Information of China (English)

    李静

    2014-01-01

    目的:探讨活血化瘀法治疗类风湿性关节炎的疗效。方法:将72例类风湿性关节炎患者按照治疗方法分为治疗组和对照组各36例,治疗组采用活血化瘀法治疗,对照组采用常规西医治疗,观察两组临床疗效、临床症状和体征以及相关实验室指标。结果:治疗组总有效率优于对照组(P<0.05);两组治疗后晨僵时间、关节疼痛评分均下降(P<0.05),握力明显提高(P<0.05),且治疗组改善水平优于对照组(P<0.05);两组治疗后红细胞沉降率(ESR)、C-反应蛋白(CRP)和类风湿因子(RF)均下降(P<0.05),且治疗组下降水平优于对照组(P<0.05)。结论:采用活血化瘀法治疗类风湿性关节炎能够有效改善患者的临床症状和体征,缓解关节疼痛。%Objective: To study the effect of promoting blood circulation and removing blood stasis on rheumatoid arthritis. Method: The 72 cases of patients with rheumatoid arthritis were selected and divided into treatment and control groups, ac-cording to the methods of treatment, 36 cases in each. Patients were treated by blood circulation and removing blood stasis therapy in treatment group and conventional western medicine treatment in control group. The clinical efficacy, clinical symp-toms and signs, as well as relevant laboratories indicators were observed in two groups. Results: The total efficiency of the observation group was significantly higher than the control group (P<0.05); the morning stiffness time and joint pain score sig-nificantly decreased after treatment both in two groups (P<0.05), and grip strength significantly increased both in two groups (P<0.05); the improvement levels of the treatment group was significantly better than the control group (P<0.05); the erythro-cyte sedimentation rate (ESR) and c-reactive protein (CRP) and rheumatoid factors (RF) decreased significantly after treatment both in two groups (P<0

  14. The Roles of Land and Orography on Precipitation and Ocean Circulation in Global Climate Models

    Science.gov (United States)

    Maroon, Elizabeth A.

    In this thesis, coupled and atmosphere-only global climate models are used to examine two large-scale climate asymmetries: the zonal asymmetry of tropical precipitation about the equator and the preference for sinking in the North Atlantic Ocean, but not in the North Pacific Ocean. The examination of these two climate asymmetries is performed using models of differing complexity. The first half of this dissertation discusses the influence of land on the distribution of tropical precipitation in idealized geometry models. A continent is added to the Northern Hemisphere subtropics of two aquaplanet models; annual mean insolation is prescribed and the albedo and longitudinal extent of the continent are varied. One of the models, GRaM, has gray-radiation physics with moist dynamics, while the other model, GFDL's AM2.1, has comprehensive physics. In the GRaM model, the pattern of the precipitation response is mostly related to decreased evaporation due to the now unsaturated surface. As the albedo of land is increased, precipitation shifts southward away from the hemisphere with less absorbed energy. In the AM2.1 model, there is a zonally-varying response in tropical precipitation due to the addition of land, but this response is not rubust in simulations that include a seasonal cycle of insolation. As albedo over land is increased, precipitation shifts southward zonally, just as in GRaM. When the width of the continent is increased, tropical precipitation shifts toward the continent, which indicates that continental width plays an important role in setting the distribution of tropical atmospheric overturning circulations. The second half of this dissertation examines the influence of Rocky Mountain orography on the location of Northern Hemisphere sinking of the oceanic meridional overturning circulation (MOC). Warren (1983) found that there is greater transport of salt into the high latitude North Atlantic than into the North Pacific, allowing water to sink in the

  15. A data driven nonlinear stochastic model for blood glucose dynamics.

    Science.gov (United States)

    Zhang, Yan; Holt, Tim A; Khovanova, Natalia

    2016-03-01

    The development of adequate mathematical models for blood glucose dynamics may improve early diagnosis and control of diabetes mellitus (DM). We have developed a stochastic nonlinear second order differential equation to describe the response of blood glucose concentration to food intake using continuous glucose monitoring (CGM) data. A variational Bayesian learning scheme was applied to define the number and values of the system's parameters by iterative optimisation of free energy. The model has the minimal order and number of parameters to successfully describe blood glucose dynamics in people with and without DM. The model accounts for the nonlinearity and stochasticity of the underlying glucose-insulin dynamic process. Being data-driven, it takes full advantage of available CGM data and, at the same time, reflects the intrinsic characteristics of the glucose-insulin system without detailed knowledge of the physiological mechanisms. We have shown that the dynamics of some postprandial blood glucose excursions can be described by a reduced (linear) model, previously seen in the literature. A comprehensive analysis demonstrates that deterministic system parameters belong to different ranges for diabetes and controls. Implications for clinical practice are discussed. This is the first study introducing a continuous data-driven nonlinear stochastic model capable of describing both DM and non-DM profiles.

  16. Modeling the effect of Causeways on Circulation in the Banana River

    Science.gov (United States)

    Saberi, A.; Weaver, R. J.

    2015-12-01

    The Indian River Lagoon (IRL) is a restricted estuary along the east coast of Florida. Although Banana River, a 50 km long sub-basin of IRL, has an outlet to the ocean through the Port Canaveral locks, the locks remain closed when there is no passing vessel. The lack of direct ocean connection results in limited circulation, long flushing time and poor water quality. Existence of the causeways limits the circulation even more. In this study, the impact of the causeways on flushing time is studied. This study also examines the extent to which constructing a low crested weir adjacent to Port Canaveral can improve flushing in this region. ADCIRC 2DDI is forced with meteorological inputs as well as tides to simulate the hydrodynamic properties of the study area and determine the 2D depth-averaged velocity field for four separate cases: Existing System with and without consideration of the causeways, and modified system (adding a weir near port Canaveral) with and without consideration of the causeways. Passive particles are placed in Banana River, and their movement is tracked using a Lagrangian Particle Tracking Model (LPTM). Transport timescales are then computed, and residence time contours as well as pathlines of selected particles are plotted. Results indicate that the narrow raised pathway section of the causeways acts as a plate which diverts the flow direction and generates eddies in the downstream which causes the particles in the vicinity of the causeways remain in the domain for a longer duration. There is a longer residence time for the case in which the causeways are considered. The results with the added weir suggest a noticeable improvement in flushing time and residence time even for the case in which the causeways are considered in the model.

  17. Simulation of Lake Victoria Circulation Patterns Using the Regional Ocean Modeling System (ROMS.

    Directory of Open Access Journals (Sweden)

    Chrispine Nyamweya

    Full Text Available Lake Victoria provides important ecosystem services including transport, water for domestic and industrial uses and fisheries to about 33 million inhabitants in three East African countries. The lake plays an important role in modulating regional climate. Its thermodynamics and hydrodynamics are also influenced by prevailing climatic and weather conditions on diel, seasonal and annual scales. However, information on water temperature and circulation in the lake is limited in space and time. We use a Regional Oceanographic Model System (ROMS to simulate these processes from 1st January 2000 to 31st December 2014. The model is based on real bathymetry, river runoff and atmospheric forcing data using the bulk flux algorithm. Simulations show that the water column exhibits annual cycles of thermo-stratification (September-May and mixing (June-August. Surface water currents take different patterns ranging from a lake-wide northward flow to gyres that vary in size and number. An under flow exists that leads to the formation of upwelling and downwelling regions. Current velocities are highest at the center of the lake and on the western inshore waters indicating enhanced water circulation in those areas. However, there is little exchange of water between the major gulfs (especially Nyanza and the open lake, a factor that could be responsible for the different water quality reported in those regions. Findings of the present study enhance understanding of the physical processes (temperature and currents that have an effect on diel, seasonal, and annual variations in stratification, vertical mixing, inshore-offshore exchanges and fluxes of nutrients that ultimately influence the biotic distribution and trophic structure. For instance information on areas/timing of upwelling and vertical mixing obtained from this study will help predict locations/seasons of high primary production and ultimately fisheries productivity in Lake Victoria.

  18. Wind driven general circulation of the Mediterranean Sea simulated with a Spectral Element Ocean Model

    Science.gov (United States)

    Molcard, A.; Pinardi, N.; Iskandarani, M.; Haidvogel, D. B.

    2002-05-01

    This work is an attempt to simulate the Mediterranean Sea general circulation with a Spectral Finite Element Model. This numerical technique associates the geometrical flexibility of the finite elements for the proper coastline definition with the precision offered by spectral methods. The model is reduced gravity and we study the wind-driven ocean response in order to explain the large scale sub-basin gyres and their variability. The study period goes from January 1987 to December 1993 and two forcing data sets are used. The effect of wind variability in space and time is analyzed and the relationship between wind stress curl and ocean response is stressed. Some of the main permanent structures of the general circulation (Gulf of Lions cyclonic gyre, Rhodes gyre, Gulf of Syrte anticylone) are shown to be induced by permanent wind stress curl structures. The magnitude and spatial variability of the wind is important in determining the appearance or disappearance of some gyres (Tyrrhenian anticyclonic gyre, Balearic anticyclonic gyre, Ionian cyclonic gyre). An EOF analysis of the seasonal variability indicates that the weakening and strengthening of the Levantine basin boundary currents is a major component of the seasonal cycle in the basin. The important discovery is that seasonal and interannual variability peak at the same spatial scales in the ocean response and that the interannual variability includes the change in amplitude and phase of the seasonal cycle in the sub-basin scale gyres and boundary currents. The Coriolis term in the vorticity balance seems to be responsible for the weakening of anticyclonic structures and their total disappearance when they are close to a boundary. The process of adjustment to winds produces a train of coastally trapped gravity waves which travel around the eastern and western basins, respectively in approximately 6 months. This corresponds to a phase velocity for the wave of about 1 m/s, comparable to an average velocity of

  19. Simulation of Lake Victoria Circulation Patterns Using the Regional Ocean Modeling System (ROMS).

    Science.gov (United States)

    Nyamweya, Chrispine; Desjardins, Christopher; Sigurdsson, Sven; Tomasson, Tumi; Taabu-Munyaho, Anthony; Sitoki, Lewis; Stefansson, Gunnar

    2016-01-01

    Lake Victoria provides important ecosystem services including transport, water for domestic and industrial uses and fisheries to about 33 million inhabitants in three East African countries. The lake plays an important role in modulating regional climate. Its thermodynamics and hydrodynamics are also influenced by prevailing climatic and weather conditions on diel, seasonal and annual scales. However, information on water temperature and circulation in the lake is limited in space and time. We use a Regional Oceanographic Model System (ROMS) to simulate these processes from 1st January 2000 to 31st December 2014. The model is based on real bathymetry, river runoff and atmospheric forcing data using the bulk flux algorithm. Simulations show that the water column exhibits annual cycles of thermo-stratification (September-May) and mixing (June-August). Surface water currents take different patterns ranging from a lake-wide northward flow to gyres that vary in size and number. An under flow exists that leads to the formation of upwelling and downwelling regions. Current velocities are highest at the center of the lake and on the western inshore waters indicating enhanced water circulation in those areas. However, there is little exchange of water between the major gulfs (especially Nyanza) and the open lake, a factor that could be responsible for the different water quality reported in those regions. Findings of the present study enhance understanding of the physical processes (temperature and currents) that have an effect on diel, seasonal, and annual variations in stratification, vertical mixing, inshore-offshore exchanges and fluxes of nutrients that ultimately influence the biotic distribution and trophic structure. For instance information on areas/timing of upwelling and vertical mixing obtained from this study will help predict locations/seasons of high primary production and ultimately fisheries productivity in Lake Victoria.

  20. Atmospheric circulation processes contributing to a multidecadal variation in reconstructed and modeled Indian monsoon precipitation

    Science.gov (United States)

    Wu, Qianru; Hu, Qi

    2015-01-01

    analysis of the recently reconstructed gridded May-September total precipitation in the Indian monsoon region for the past half millennium discloses significant variations at multidecadal timescales. Meanwhile, paleo-climate modeling outputs from the National Center for Atmospheric Research Community Climate System Model 4.0 show similar multidecadal variations in the monsoon precipitation. One of those variations at the frequency of 40-50 years per cycle is examined in this study. Major results show that this variation is a product of the processes in that the meridional gradient of the atmospheric enthalpy is strengthened by radiation loss in the high-latitude and polar region. Driven by this gradient and associated baroclinicity in the atmosphere, more heat/energy is generated in the tropical and subtropical (monsoon) region and transported poleward. This transport relaxes the meridional enthalpy gradient and, subsequently, the need for heat production in the monsoon region. The multidecadal timescale of these processes results from atmospheric circulation-radiation interactions and the inefficiency in generation of kinetic energy from the potential energy in the atmosphere to drive the eddies that transport heat poleward. This inefficiency creates a time delay between the meridional gradient of the enthalpy and the poleward transport. The monsoon precipitation variation lags that in the meridional gradient of enthalpy but leads that of the poleward heat transport. This phase relationship, and underlining chasing process by the transport of heat to the need for it driven by the meridional enthalpy gradient, sustains this multidecadal variation. This mechanism suggests that atmospheric circulation processes can contribute to multidecadal timescale variations. Interactions of these processes with other forcing, such as sea surface temperature or solar irradiance anomalies, can result in resonant or suppressed variations in the Indian monsoon precipitation.

  1. [A Nude Mouse Model for Human Umbilical Cord Blood Transplantation

    Science.gov (United States)

    Lan, Jiongcai; Liu, Hongyu; Chen, Qiang; Yang, Chongli; Zhang, Zhimei

    2000-03-01

    To evaluate the hematopoietic potentiality and the migration and homing routine of separated as well as cryopreserved umbilical cord blood hematopoietic cells, the BALB/cnu(+) mice were used to establish a murine model. This can prepare for the clinical transplantation and the establishment of a large-scale cord blood bank. The result indicated that the hydroxyethyl starch (HES) sedimentation and DMSO step-by-step cryopreservation procedure resulted in only less losses of hematopoietic progenitor cells and also unharmful to the hematopietic potentiality. We can found evidence for successful transplantation in each mouse which received (1.0 - 2.0) x 10(7) separated or cryopresered hematopoietic cells from cord blood, which lasted for about fifty days. The results demonstrated that (1) HES sedimentation and DMSO cryopreservation procedure can keep the hematopoietic potentiality of cord blood, and so can be used to clinical transplantation or establishment of a cord blood bank; (2) Rich hematopoietic stem cells in human cord blood can cross the xenogenetic barriers and successfully engraft mice; (3) The hematopoietic cells migrated among bone marrow, liver, spleen, lung and kidney in the mice and homed to bone marrow by the end. Cryopreservation may influence the adhesion molecule on the hematopoietic cells and the homing behaviour, but not influence their hematopoietic potentiality.

  2. Seamless particle-based modeling of blood clotting

    Science.gov (United States)

    Yazdani, Alireza; Karniadakis, George

    2016-11-01

    We propose a new multiscale framework that seamlessly integrate four key components of blood clotting namely, blood rheology, cell mechanics, coagulation kinetics and transport of species and platelet adhesive dynamics. We use transport dissipative particle dynamics (tDPD) which is an extended form of original DPD as the base solver to model both blood flow and the reactive transport of chemical species in the coagulation cascade. Further, we use a coarse-grained representation of blood cell's membrane that accounts for its mechanics; both red blood cells and platelets are resolved at sub-cellular resolution, and stochastic bond formation/dissociation are included to account for platelet adhesive dynamics at the site of injury. Our results show good qualitative agreement with in vivo experiments. The numerical framework allows us to perform systematic analysis on different mechanisms of blood clotting. In addition, this new multiscale particle-based methodology can open new directions in addressing different biological processes from sub-cellular to macroscopic scales. NIH Grant No. U01HL116323.

  3. A regional ocean circulation model for the mid-Cretaceous North Atlantic Basin: implications for black shale formation

    Directory of Open Access Journals (Sweden)

    R. P. M. Topper

    2011-03-01

    Full Text Available High concentrations of organic matter accumulated in marine sediments during Oceanic Anoxic Events (OAEs in the Cretaceous. Model studies examining these events invariably make use of global ocean circulation models. In this study, a regional model for the North Atlantic Basin during OAE2 at the Cenomanian-Turonian boundary has been developed. A first order check of the results has been performed by comparison with the results of a recent global Cenomanian CCSM3 run, from which boundary and initial conditions were obtained. The regional model is able to maintain tracer patterns and to produce velocity patterns similar to the global model. The sensitivity of the basin tracer and circulation patterns to changes in the geometry of the connections with the global ocean is examined with three experiments with different bathymetries near the sponges. Different geometries turn out to have little effect on tracer distribution, but do affect circulation and upwelling patterns. The regional model is also used to test the hypothesis that ocean circulation may have been behind the deposition of black shales during OAEs. Three scenarios are tested which are thought to represent pre-OAE, OAE and post-OAE situations. Model results confirm that Pacific intermediate inflow together with coastal upwelling could have enhanced primary production during OAE2. A low sea level in the pre-OAE scenario could have inhibited large scale black shale formation, as could have the opening of the Equatorial Atlantic Seaway in the post-OAE scenario.

  4. Analysing and combining atmospheric general circulation model simulations forced by prescribed SST. Tropical response

    Energy Technology Data Exchange (ETDEWEB)

    Moron, V. [Universite' de Provence, UFR des sciences geographiques et de l' amenagement, Aix-en-Provence (France); Navarra, A. [Istituto Nazionale di Geofisica e Vulcanologia, Bologna (Italy); Ward, M. N. [University of Oklahoma, Cooperative Institute for Mesoscale Meteorological Studies, Norman OK (United States); Foland, C. K. [Hadley Center for Climate Prediction and Research, Meteorological Office, Bracknell (United Kingdom); Friederichs, P. [Meteorologisches Institute des Universitaet Bonn, Bonn (Germany); Maynard, K.; Polcher, J. [Paris Universite' Pierre et Marie Curie, Paris (France). Centre Nationale de la Recherche Scientifique, Laboratoire de Meteorologie Dynamique, Paris

    2001-08-01

    The ECHAM 3.2 (T21), ECHAM (T30) and LMD (version 6, grid-point resolution with 96 longitudes x 72 latitudes) atmospheric general circulation models were integrated through the period 1961 to 1993 forces with the same observed Sea Surface Temperatures (SSTs) as compiled at the Hadley Centre. Three runs were made for each model starting from different initial conditions. The large-scale tropical inter-annual variability is analysed to give a picture of a skill of each model and of some sort of combination of the three models. To analyse the similarity of model response averaged over the same key regions, several widely-used indices are calculated: Southern Oscillation Index (SOI), large-scale wind shear indices of the boreal summer monsoon in Asia and West Africa and rainfall indices for NE Brazil, Sahel and India. Even for the indices where internal noise is large, some years are consistent amongst all the runs, suggesting inter-annual variability of the strength of SST forcing. Averaging the ensemble mean of the three models (the super-ensemble mean) yields improved skill. When each run is weighted according to its skill, taking three runs from different models instead of three runs of the same model improves the mean skill. There is also some indication that one run of a given model could be better than another, suggesting that persistent anomalies could change its sensitivity to SST. The index approach lacks flexibility to assess whether a model's response to SST has been geographically displaced. It can focus on the first mode in the global tropics, found through singular value decomposition analysis, which is clearly related to El Nino/Southern Oscillation (ENSO) in all seasons. The Observed-Model and Model-Model analyses lead to almost the same patterns, suggesting that the dominant pattern of model response is also the most skilful mode. Seasonal modulation of both skill and spatial patterns (both model and observed) clearly exists with highest skill

  5. Global environmental effects of impact-generated aerosols: Results from a general circulation model

    Science.gov (United States)

    Covey, Curt; Ghan, Steven J.; Walton, John J.; Weissman, Paul R.

    1989-01-01

    Interception of sunlight by the high altitude worldwide dust cloud generated by impact of a large asteroid or comet would lead to substantial land surface cooling, according to the three-dimensional atmospheric general circulation model (GCM). This result is qualitatively similar to conclusions drawn from an earlier study that employed a one-dimensional atmospheric model, but in the GCM simulation the heat capacity of the oceans, not included in the one-dimensional model, substantially mitigates land surface cooling. On the other hand, the low heat capacity of the GCM's land surface allows temperatures to drop more rapidly in the initial stages of cooling than in the one-dimensional model study. GCM-simulated climatic changes in the scenario of asteroid/comet winter are more severe than in nuclear winter because the assumed aerosol amount is large enough to intercept all sunlight falling on earth. Impacts of smaller objects could also lead to dramatic, though of course less severe, climatic changes, according to the GCM. An asteroid or comet impact would not lead to anything approaching complete global freezing, but quite reasonable to assume that impacts would dramatically alter the climate in at least a patchy sense.

  6. A circulation modeling approach for evaluating the conditions for shoreline instabilities

    Science.gov (United States)

    List, Jeffrey H.; Ashton, Andrew D.

    2007-01-01

    Analytical models predict the growth (instability) of shoreline salients when deep-water waves approach the coast from highly oblique angles, contrary to classical shoreline change models in which shoreline salients can only dissipate. Using the process-based wave, circulation, and sediment transport model Delft3D, we test this prediction for simulated bathymetric and wave characteristics approximating the open-ocean conditions at Duck, North Carolina. We consider two cases: a uniform coast with a varying wave approach angle, and a bathymetry with coastal salients and a single high-angle boundary wave condition. Incident wave conditions include a swell case with no wind and a wind-wave case with active local wave regeneration by wind. The uniform-coast tests predict transport maxima at oblique wave angles for both wave cases, indicating the potential for shoreline instabilities, similar to the analytical models. However, the critical angle for instability is much higher in the wind-wave case. Our tests with coastal salients agree with previous findings that a minimum salient length scale may be required for the instability effect to be active. Here, a salient with a longshore scale of 4 km results in transport divergence (erosion; no instability) at the salient crest while an 8 km salient results in transport convergence (accretion; instability) at the crest.

  7. A stabilized proper orthogonal decomposition reduced-order model for large scale quasigeostrophic ocean circulation

    CERN Document Server

    San, Omer

    2014-01-01

    In this paper, a stabilized proper orthogonal decomposition (POD) reduced-order model (ROM) is presented for the barotropic vorticity equation. We apply the POD-ROM model to mid-latitude simplified oceanic basins, which are standard prototypes of more realistic large-scale ocean dynamics. A mode dependent eddy viscosity closure scheme is used to model the effects of the discarded POD modes. A sensitivity analysis with respect to the free eddy viscosity stabilization parameter is performed for various POD-ROMs with different numbers of POD modes. The POD-ROM results are validated against the Munk layer resolving direct numerical simulations using a fully conservative fourth-order Arakawa scheme. A comparison with the standard Galerkin POD-ROM without any stabilization is also included in our investigation. Significant improvements in the accuracy over the standard Galerkin model are shown for a four-gyre ocean circulation problem. This first step in the numerical assessment of the POD-ROM shows that it could r...

  8. Evaluation of the Surface Representation of the Greenland Ice Sheet in a General Circulation Model

    Science.gov (United States)

    Cullather, Richard I.; Nowicki, Sophie M. J.; Zhao, Bin; Suarez, Max J.

    2014-01-01

    Simulated surface conditions of the Goddard Earth Observing System model, version 5 (GEOS 5) atmospheric general circulation model (AGCM) are examined for the contemporary Greenland Ice Sheet (GrIS). A surface parameterization that explicitly models surface processes including snow compaction, meltwater percolation and refreezing, and surface albedo is found to remedy an erroneous deficit in the annual net surface energy flux and provide an adequate representation of surface mass balance (SMB) in an evaluation using simulations at two spatial resolutions. The simulated 1980-2008 GrIS SMB average is 24.7+/-4.5 cm yr(- 1) water-equivalent (w.e.) at.5 degree model grid spacing, and 18.2+/-3.3 cm yr(- 1) w.e. for 2 degree grid spacing. The spatial variability and seasonal cycle of the simulation compare favorably to recent studies using regional climate models, while results from 2 degree integrations reproduce the primary features of the SMB field. In comparison to historical glaciological observations, the coarser resolution model overestimates accumulation in the southern areas of the GrIS, while the overall SMB is underestimated. These changes relate to the sensitivity of accumulation and melt to the resolution of topography. The GEOS-5 SMB fields contrast with available corresponding atmospheric models simulations from the Coupled Model Intercomparison Project (CMIP5). It is found that only a few of the CMIP5 AGCMs examined provide significant summertime runoff, a dominant feature of the GrIS seasonal cycle. This is a condition that will need to be remedied if potential contributions to future eustatic change from polar ice sheets are to be examined with GCMs.

  9. Risk Factor Analyses for the Return of Spontaneous Circulation in the Asphyxiation Cardiac Arrest Porcine Model

    Directory of Open Access Journals (Sweden)

    Cai-Jun Wu

    2015-01-01

    Full Text Available Background: Animal models of asphyxiation cardiac arrest (ACA are frequently used in basic research to mirror the clinical course of cardiac arrest (CA. The rates of the return of spontaneous circulation (ROSC in ACA animal models are lower than those from studies that have utilized ventricular fibrillation (VF animal models. The purpose of this study was to characterize the factors associated with the ROSC in the ACA porcine model. Methods: Forty-eight healthy miniature pigs underwent endotracheal tube clamping to induce CA. Once induced, CA was maintained untreated for a period of 8 min. Two minutes following the initiation of cardiopulmonary resuscitation (CPR, defibrillation was attempted until ROSC was achieved or the animal died. To assess the factors associated with ROSC in this CA model, logistic regression analyses were performed to analyze gender, the time of preparation, the amplitude spectrum area (AMSA from the beginning of CPR and the pH at the beginning of CPR. A receiver-operating characteristic (ROC curve was used to evaluate the predictive value of AMSA for ROSC. Results: ROSC was only 52.1% successful in this ACA porcine model. The multivariate logistic regression analyses revealed that ROSC significantly depended on the time of preparation, AMSA at the beginning of CPR and pH at the beginning of CPR. The area under the ROC curve in for AMSA at the beginning of CPR was 0.878 successful in predicting ROSC (95% confidence intervals: 0.773∼0.983, and the optimum cut-off value was 15.62 (specificity 95.7% and sensitivity 80.0%. Conclusions: The time of preparation, AMSA and the pH at the beginning of CPR were associated with ROSC in this ACA porcine model. AMSA also predicted the likelihood of ROSC in this ACA animal model.

  10. Evaluating the Climate Role of Tropical Cyclones Using an Atmospheric General Circulation Model

    Science.gov (United States)

    Winterbottom, H. R.; Pegion, P. J.; Hart, R. E.

    2011-12-01

    A formal assessment and an identification for the global circulation impact of a tropical cyclone (TC) remains in the developmental stages. This area of research was first suggested by Bengtsson et al., [1982], when questions were posed regarding the role of TCs with respect to the poleward transport of heat, moisture, and momentum. To date, much attention has been paid to the role of oceanic heat transport [Emanuel, 2001; Sriver and Huber, 2007; Hart et al., 2007; Liu et al., 2008; Hu and Meehl, 2009]. Fewer studies, however, have identified an explicit role for the TC within the atmosphere, although recent work has begun to quantify the magnitude of that atmospheric footprint from reanalysis datasets [Hart et al., 2007; Schenkel and Hart, 2011]. A recent study by Hart [2011] deduced a statistical relationship between northern hemisphere TC activity (evaluated using both TC count and power dissipation [Emanuel, 2007]) and the subsequent winter climate. Hart [2011] ascertained that there exists a strong (statistical) inverse relationship between the amount of pole-ward TC power-dissipation (e.g., recurving TCs) and the 500-hPa extratropical stationary eddy-temperature flux, and speculated on the physical (and potential nonphysical) explanations for such a relationship. Indeed, the relationship was so strong that it was the most robust predictor of this measure of wind activity amidst all known teleconnection indices. These prior works provide the foundation on which to further explore the TC role in climate. Accordingly, in this study, we diagnose the climatic impact of TCs upon the Earth's general circulation using the National Center for Atmospheric Research (NCAR) Community Atmosphere Model (CAM) and the TC vortex removal procedure discussed by Winterbottom and Chassignet [2011]. A series of experiments with and without TCs will be compared. We will evaluate the mean and transient eddy fluxes as a function of a simulation with TCs and a simulation without. We

  11. Space weather circulation model of plasma clouds as background radiation medium of space environment.

    Science.gov (United States)

    Kalu, A. E.

    A model for Space Weather (SW) Circulation with Plasma Clouds as background radiation medium of Space Environment has been proposed and discussed. Major characteristics of the model are outlined and the model assumes a baroclinic Space Environment in view of observed pronounced horizontal electron temperature gradient with prevailing weak vertical temperature gradient. The primary objective of the study is to be able to monitor and realistically predict on real- or near real-time SW and Space Storms (SWS) affecting human economic systems on Earth as well as the safety and Physiologic comfort of human payload in Space Environment in relation to planned increase in human space flights especially with reference to the ISS Space Shuttle Taxi (ISST) Programme and other prolonged deep Space Missions. Although considerable discussions are now available in the literature on SW issues, routine Meteorological operational applications of SW forecast data and information for Space Environment are still yet to receive adequate attention. The paper attempts to fill this gap in the literature of SW. The paper examines the sensitivity and variability in 3-D continuum of Plasmas in response to solar radiation inputs into the magnetosphere under disturbed Sun condition. Specifically, the presence of plasma clouds in the form of Coronal Mass Ejections (CMEs) is stressed as a major source of danger to Space crews, spacecraft instrumentation and architecture charging problems as well as impacts on numerous radiation - sensitive human economic systems on Earth. Finally, the paper considers the application of model results in the form of effective monitoring of each of the two major phases of manned Spaceflights - take-off and re-entry phases where all-time assessment of spacecraft transient ambient micro-incabin and outside Space Environment is vital for all manned Spaceflights as recently evidenced by the loss of vital information during take-off of the February 1, 2003 US Columbia

  12. Using peripheral blood circulating DNAs to detect CpG global methylation status and genetic mutations in patients with myelodysplastic syndrome

    Energy Technology Data Exchange (ETDEWEB)

    Iriyama, Chisako [Department of Hematology and Oncology, Nagoya University Graduate School of Medicine, Nagoya (Japan); Tomita, Akihiro, E-mail: atomita@med.nagoya-u.ac.jp [Department of Hematology and Oncology, Nagoya University Graduate School of Medicine, Nagoya (Japan); Hoshino, Hideaki; Adachi-Shirahata, Mizuho [Department of Hematology and Oncology, Nagoya University Graduate School of Medicine, Nagoya (Japan); Furukawa-Hibi, Yoko; Yamada, Kiyofumi [Department of Neuropsychopharmacology and Hospital Pharmacy, Nagoya University School of Medicine, Nagoya (Japan); Kiyoi, Hitoshi; Naoe, Tomoki [Department of Hematology and Oncology, Nagoya University Graduate School of Medicine, Nagoya (Japan)

    2012-03-23

    Highlights: Black-Right-Pointing-Pointer Circulating DNAs (CDs) can be used to detect genetic/epigenetic abnormalities in MDS. Black-Right-Pointing-Pointer Epigenetic changes can be detected more sensitively when using plasma DNA than PBMNC. Black-Right-Pointing-Pointer Mutation ratio in CDs may reflect the ratio in stem cell population in bone marrow. Black-Right-Pointing-Pointer Using CDs can be a safer alternate strategy compared to bone marrow aspiration. -- Abstract: Myelodysplastic syndrome (MDS) is a hematopoietic stem cell disorder. Several genetic/epigenetic abnormalities are deeply associated with the pathogenesis of MDS. Although bone marrow (BM) aspiration is a common strategy to obtain MDS cells for evaluating their genetic/epigenetic abnormalities, BM aspiration is difficult to perform repeatedly to obtain serial samples because of pain and safety concerns. Here, we report that circulating cell-free DNAs from plasma and serum of patients with MDS can be used to detect genetic/epigenetic abnormalities. The plasma DNA concentration was found to be relatively high in patients with higher blast cell counts in BM, and accumulation of DNA fragments from mono-/di-nucleosomes was confirmed. Using serial peripheral blood (PB) samples from patients treated with hypomethylating agents, global methylation analysis using bisulfite pyrosequencing was performed at the specific CpG sites of the LINE-1 promoter. The results confirmed a decrease of the methylation percentage after treatment with azacitidine (days 3-9) using DNAs from plasma, serum, and PB mono-nuclear cells (PBMNC). Plasma DNA tends to show more rapid change at days 3 and 6 compared with serum DNA and PBMNC. Furthermore, the TET2 gene mutation in DNAs from plasma, serum, and BM cells was quantitated by pyrosequencing analysis. The existence ratio of mutated genes in plasma and serum DNA showed almost equivalent level with that in the CD34+/38- stem cell population in BM. These data suggest that genetic

  13. Molecular diagnosis of toxoplasmosis: value of the buffy coat for the detection of circulating Toxoplasma gondii.

    Science.gov (United States)

    Brenier-Pinchart, Marie-Pierre; Capderou, Elodie; Bertini, Rose-Laurence; Bailly, Sébastien; Fricker-Hidalgo, Hélène; Varlet-Marie, Emmanuelle; Murat, Jean-Benjamin; Sterkers, Yvon; Touafek, Fériel; Bastien, Patrick; Pelloux, Hervé

    2015-08-01

    Early detection of Toxoplasma tachyzoites circulating in blood using PCR is recommended for immunosuppressed patients at high risk for disseminated toxoplasmosis. Using a toxoplasmosis mouse model, we show that the sensitivity of detection is higher using buffy coat isolated from a large blood volume than using whole blood for this molecular monitoring.

  14. On the validation of a realistic model of mesoscale coastal circulation in the Western Iberian Peninsula

    Science.gov (United States)

    Dubert, Jesus; Cordeiro, Nuno; Nolasco, Rita

    2010-05-01

    Realistic simulations of the circulation off the Western Iberian Peninsula, for the period 2001-2009 are compared against satellite observations of sea surface temperature (SST), for the summer upwelling season. This was done by means of comparisons of climatological means of monthly sst, standard deviation, and monthly anomalies obtained from satellite, and from the numerical model. Also, the observed mesoscale structures like filaments, are also compared with those obtained with the model, for the same period. The model consists in a ROMS-AGRIF configuration at ~3km resolution, forced with 6h NCEP2 reanalysis and Quikscat forcing for winds for the referred period, in the presence of river inflow for the main rivers of the region. The boundary conditions are obtained by offline nesting from a configuration of a larger domain, forced in the same way, and offshore Levitus climatological boundaries. The filament characterization for the satellite data, and the outputs of the numerical model, was done based on an automatic data treatment, which allows to study the filaments seasonal and interannual variability for the studied period. It was also made a study and a discussion of the surface climatology based on the satellite images and the model, in order to characterize, the surface temperature field, the monthly means, standard deviation and the deviations from the mean. In order to explain the observed and modelled anomalies, NCEP winds reanalysis are used in several points in the studied domain. The main purpose of this study is a step forward in the validation of the numerical configuration resolving mesoscale in the Western Iberian Peninsula, and to is to determine whether or not the model is able to reproduce the observed mesoscale features, the monthly anomalies of sst, and the monthly climatology.

  15. Successive bifurcations in a shallow-water model applied to the wind-driven ocean circulation

    Directory of Open Access Journals (Sweden)

    1995-01-01

    Full Text Available Climate - the "coarse-gridded" state of the coupled ocean - atmosphere system - varies on many time and space scales. The challenge is to relate such variation to specific mechanisms and to produce verifiable quantitative explanations. In this paper, we study the oceanic component of the climate system and, in particular, the different circulation regimes of the mid-latitude win driven ocean on the interannual time scale. These circulations are dominated by two counterrotating, basis scale gyres: subtropical and subpolar. Numerical techniques of bifurcation theory are used to stud the multiplicity and stability of the steady-state solution of a wind-driven, double-gyre, reduced-gravity, shallow water model. Branches of stationary solutions and their linear stability are calculated systematically as parameter are varied. This is one of the first geophysical studies i which such techniques are applied to a dynamical system with tens of thousands of degrees of freedom. Multiple stationary solutions obtain as a result of nonlinear interactions between the two main recirculating cell (cyclonic and anticyclonic of the large- scale double-gyre flow. These equilibria appear for realistic values of the forcing and dissipation parameters. They undergo Hop bifurcation and transition to aperiodic solutions eventually occurs. The periodic and chaotic behaviour is probably related to an increased number of vorticity cells interaction with each other. A preliminary comparison with observations of the Gulf Stream and Kuroshio Extensions suggests that the intern variability of our simulated mid-latitude ocean is a important factor in the observed interannual variability o these two current systems.

  16. A Python Implementation of an Intermediate-Level Tropical Circulation Model and Implications for How Modeling Science is Done

    Science.gov (United States)

    Lin, J. W. B.

    2015-12-01

    Historically, climate models have been developed incrementally and in compiled languages like Fortran. While the use of legacy compiledlanguages results in fast, time-tested code, the resulting model is limited in its modularity and cannot take advantage of functionalityavailable with modern computer languages. Here we describe an effort at using the open-source, object-oriented language Pythonto create more flexible climate models: the package qtcm, a Python implementation of the intermediate-level Neelin-Zeng Quasi-Equilibrium Tropical Circulation model (QTCM1) of the atmosphere. The qtcm package retains the core numerics of QTCM1, written in Fortran, to optimize model performance but uses Python structures and utilities to wrap the QTCM1 Fortran routines and manage model execution. The resulting "mixed language" modeling package allows order and choice of subroutine execution to be altered at run time, and model analysis and visualization to be integrated in interactively with model execution at run time. This flexibility facilitates more complex scientific analysis using less complex code than would be possible using traditional languages alone and provides tools to transform the traditional "formulate hypothesis → write and test code → run model → analyze results" sequence into a feedback loop that can be executed automatically by the computer.

  17. Transcriptional profiling of the circulating immune response to lassa virus in an aerosol model of exposure.

    Directory of Open Access Journals (Sweden)

    Shikha Malhotra

    Full Text Available Lassa virus (LASV is a significant human pathogen that is endemic to several countries in West Africa. Infection with LASV leads to the development of hemorrhagic fever in a significant number of cases, and it is estimated that thousands die each year from the disease. Little is known about the complex immune mechanisms governing the response to LASV or the genetic determinants of susceptibility and resistance to infection. In the study presented here, we have used a whole-genome, microarray-based approach to determine the temporal host response in the peripheral blood mononuclear cells (PBMCs of non-human primates (NHP following aerosol exposure to LASV. Sequential sampling over the entire disease course showed that there are strong transcriptional changes of the immune response to LASV exposure, including the early induction of interferon-responsive genes and Toll-like receptor signaling pathways. However, this increase in early innate responses was coupled with a lack of pro-inflammatory cytokine response in LASV exposed NHPs. There was a distinct lack of cytokines such as IL1β and IL23α, while immunosuppressive cytokines such as IL27 and IL6 were upregulated. Comparison of IRF/STAT1-stimulated gene expression with the viral load in LASV exposed NHPs suggests that mRNA expression significantly precedes viremia, and thus might be used for early diagnostics of the disease. Our results provide a transcriptomic survey of the circulating immune response to hemorrhagic LASV exposure and provide a foundation for biomarker identification to allow clinical diagnosis of LASV infection through analysis of the host response.

  18. Transcriptional profiling of the circulating immune response to lassa virus in an aerosol model of exposure.

    Science.gov (United States)

    Malhotra, Shikha; Yen, Judy Y; Honko, Anna N; Garamszegi, Sara; Caballero, Ignacio S; Johnson, Joshua C; Mucker, Eric M; Trefry, John C; Hensley, Lisa E; Connor, John H

    2013-01-01

    Lassa virus (LASV) is a significant human pathogen that is endemic to several countries in West Africa. Infection with LASV leads to the development of hemorrhagic fever in a significant number of cases, and it is estimated that thousands die each year from the disease. Little is known about the complex immune mechanisms governing the response to LASV or the genetic determinants of susceptibility and resistance to infection. In the study presented here, we have used a whole-genome, microarray-based approach to determine the temporal host response in the peripheral blood mononuclear cells (PBMCs) of non-human primates (NHP) following aerosol exposure to LASV. Sequential sampling over the entire disease course showed that there are strong transcriptional changes of the immune response to LASV exposure, including the early induction of interferon-responsive genes and Toll-like receptor signaling pathways. However, this increase in early innate responses was coupled with a lack of pro-inflammatory cytokine response in LASV exposed NHPs. There was a distinct lack of cytokines such as IL1β and IL23α, while immunosuppressive cytokines such as IL27 and IL6 were upregulated. Comparison of IRF/STAT1-stimulated gene expression with the viral load in LASV exposed NHPs suggests that mRNA expression significantly precedes viremia, and thus might be used for early diagnostics of the disease. Our results provide a transcriptomic survey of the circulating immune response to hemorrhagic LASV exposure and provide a foundation for biomarker identification to allow clinical diagnosis of LASV infection through analysis of the host response.

  19. Quasi-steady model for predicting temperature of aqueous foams circulating in geothermal wellbores

    Energy Technology Data Exchange (ETDEWEB)

    Blackwell, B.F.; Ortega, A.

    1983-01-01

    A quasi-steady model has been developed for predicting the temperature profiles of aqueous foams circulating in geothermal wellbores. The model assumes steady one-dimensional incompressible flow in the wellbore; heat transfer by conduction from the geologic formation to the foam is one-dimensional radially and time-dependent. The vertical temperature distribution in the undisturbed geologic formation is assumed to be composed of two linear segments. For constant values of the convective heat-transfer coefficient, a closed-form analytical solution is obtained. It is demonstrated that the Prandtl number of aqueous foams is large (1000 to 5000); hence, a fully developed temperature profile may not exist for representative drilling applications. Existing convective heat-transfer-coefficient solutions are adapted to aqueous foams. The simplified quasi-steady model is successfully compared with a more-sophisticated finite-difference computer code. Sample temperature-profile calculations are presented for representative values of the primary parameters. For a 5000-ft wellbore with a bottom hole temperature of 375{sup 0}F, the maximum foam temperature can be as high as 300{sup 0}F.

  20. CFD modeling of stripper ash cooler of circulating fluidized bed boiler

    Directory of Open Access Journals (Sweden)

    Ravi Inder Singh

    2016-09-01

    Full Text Available The stable operation of a bottom ash cooler is vital for the operation of the circulating fluidized bed boiler. To assess, the stability of the ash cooler, it is important to have a thorough understanding of the flow behaviour. Although, many experimental results been reported in literature, CFD modelling of the ash cooler has not been carried out. In this paper, the transient computational analysis of a novel stripper ash cooler has been carried out using the Eulerian–Eulerian multiphase approach. The phase coupled SIMPLE algorithm has been used to solve the multiphase equations and the Gidaspow drag model has been employed to model the interaction between the fluidized air and ash. Two cases have been analysed in this paper. In the first case, the filling of the ash in the cooler has been analysed and in the second case, the phenomenon of fluidized bed bubbling in the ash cooler has been simulated. The study the of flow characteristics of hot ash has been studied. The contours of temperature, phase volume and bubbling have been analyzed in this paper.

  1. A logistic model for the detection of circulating tumour cells in human metastatic colorectal cancer

    Science.gov (United States)

    Barbazán, Jorge; Vieito, María; Abalo, Alicia; Alonso-Alconada, Lorena; Muinelo-Romay, Laura; Alonso-Nocelo, Marta; León, Luís; Candamio, Sonia; Gallardo, Elena; Anido, Urbano; Doll, Andreas; los Ángeles Casares, María; Gómez-Tato, Antonio; Abal, Miguel; López-López, Rafael

    2012-01-01

    The accuracy in the diagnosis of metastatic colorectal cancer (mCRC) represents one of the challenges in the clinical management of patients. The detection of circulating tumour cells (CTC) is becoming a promising alternative to current detection techniques, as it focuses on one of the players of the metastatic disease and it should provide with more specific and sensitive detection rates. Here, we describe an improved method of detection of CTC from mCRC patients by combining immune-enrichment, optimal purification of RNA from very low cell numbers, and the selection of accurate PCR probes. As a result, we obtained a logistic model that combines GAPDH and VIL1 normalized to CD45 rendering powerful results in the detection of CTC from mCRC patients (AUROC value 0.8599). We further demonstrated the utility of this model at the clinical setting, as a reliable prognosis tool to determine progression-free survival in mCRC patients. Overall, we developed a strategy that ameliorates the specificity and sensitivity in the detection of CTC, resulting in a robust and promising logistic model for the clinical management of metastatic colorectal cancer patients. PMID:22304365

  2. An Efficient Coarse Grid Projection Method for Quasigeostrophic Models of Large-Scale Ocean Circulation

    CERN Document Server

    San, Omer

    2013-01-01

    This paper puts forth a coarse grid projection (CGP) multiscale method to accelerate computations of quasigeostrophic (QG) models for large scale ocean circulation. These models require solving an elliptic sub-problem at each time step, which takes the bulk of the computational time. The method we propose here is a modular approach that facilitates data transfer with simple interpolations and uses black-box solvers for solving the elliptic sub-problem and potential vorticity equations in the QG flow solvers. After solving the elliptic sub-problem on a coarsened grid, an interpolation scheme is used to obtain the fine data for subsequent time stepping on the full grid. The potential vorticity field is then updated on the fine grid with savings in computational time due to the reduced number of grid points for the elliptic solver. The method is applied to both single layer barotropic and two-layer stratified QG ocean models for mid-latitude oceanic basins in the beta plane, which are standard prototypes of more...

  3. Excitation of equatorial Kelvin and Yanai waves by tropical cyclones in an ocean general circulation model

    Directory of Open Access Journals (Sweden)

    R. L. Sriver

    2012-09-01

    Full Text Available Tropical cyclones (TCs actively contribute to the dynamics of Earth's coupled climate system. They influence oceanic mixing rates, upper-ocean heat content, and air-sea fluxes, with implications for atmosphere and ocean dynamics on multiple spatial and temporal scales. Using an ocean general circulation model with modified surface wind forcing, we explore how TC winds can excite equatorial ocean waves in the tropical Pacific. We highlight a situation where three successive TCs in the western North Pacific region, corresponding to events in 2003, excite a combination of Kelvin and Yanai waves in the equatorial Pacific. The resultant thermocline adjustment significantly modifies the thermal structure of the upper equatorial Pacific and leads to eastward zonal heat transport. Observations of upper-ocean temperature by the Tropical Atmosphere Ocean (TAO buoy array and sea-level height anomalies using altimetry reveal wave passage during the same time period with similar properties to the modeled wave, although our idealized model methodology disallows precise identification of the TC forcing with the observed waves. Results indicate that direct oceanographic forcing by TCs may be important for understanding the spectrum of equatorial ocean waves, thus remotely influencing tropical mixing and surface energy budgets. Because equatorial Kelvin waves are closely linked to interannual variability in the tropical Pacific, these findings also suggest TC wind forcing may influence the timing and amplitude of El Niño events.

  4. Response of an ocean general circulation model to wind and thermodynamic forcings

    Indian Academy of Sciences (India)

    A Chakraborty; H C Upadhyaya; O P Sharma

    2000-09-01

    The stretched-coordinate ocean general circulation model has been designed to study the observed variability due to wind and thermodynamic forcings. The model domain extends from 60°N to 60°S and cyclically continuous in the longitudinal direction. The horizontal resolution is 5° × 5° and 9 discrete vertical levels. First a spin-up experiment has been done with ECMWF-AMIP 1979 January mean fields. The wind stress, ambient atmospheric temperature, evaporation and precipitation have been used in order to derive mechanical and thermodynamical surface forcings. Next, the experiment has been extended for another 30 years (3 cycles each of 10 year period) with varying surface boundary conditions (from January 1979 to December 1988 of ECMWF-AMIP monthly fields for each cycle) along with 120 years extended spin-up control run's results as initial conditions. The results presented here are for the last 10 years simulations. The preliminary results of this experiment show that the model is capable of simulating some of the general features and the pattern of interannual variability of the ocean.

  5. Excitation of equatorial Kelvin and Yanai waves by tropical cyclones in an ocean general circulation model

    Directory of Open Access Journals (Sweden)

    R. L. Sriver

    2013-01-01

    Full Text Available Tropical cyclones (TCs actively contribute to the dynamics of Earth's coupled climate system. They influence oceanic mixing rates, upper-ocean heat content, and air–sea fluxes, with implications for atmosphere and ocean dynamics on multiple spatial and temporal scales. Using an ocean general circulation model with modified surface wind forcing, we explore how TC winds can excite equatorial ocean waves in the tropical Pacific. We highlight a situation where three successive TCs in the western North Pacific region, corresponding to events in 2003, excite a combination of Kelvin and Yanai waves in the equatorial Pacific. The resultant thermocline adjustment significantly modifies the thermal structure of the upper equatorial Pacific and leads to eastward zonal heat transport. Observations of upper-ocean temperature by the Tropical Atmosphere Ocean (TAO buoy array and sea-level height anomalies using altimetry reveal wave passage during the same time period with similar properties to the modeled wave, although our idealized model methodology disallows precise identification of the TC forcing with the observed waves. Results indicate that direct oceanographic forcing by TCs may be important for understanding the spectrum of equatorial ocean waves, thus remotely influencing tropical mixing and surface energy budgets. Because equatorial Kelvin waves are closely linked to interannual variability in the tropical Pacific, these findings also suggest TC wind forcing may influence the timing and amplitude of El Niño events.

  6. Key Elements of the User-Friendly, GFDL SKYHI General Circulation Model

    Directory of Open Access Journals (Sweden)

    Richard S. Hemler

    2000-01-01

    Full Text Available Over the past seven years, the portability of the GFDL SKYHI general circulation model has greatly increased. Modifications to the source code have allowed SKYHI to be run on the GFDL Cray Research PVP machines, the TMC CM-5 machine at Los Alamos National Laboratory, and more recently on the GFDL 40-processor Cray Research T3E system. At the same time, changes have been made to the model to make it more usable and flexible. Because of the reduction of the human resources available to manage and analyze scientific experiments, it is no longer acceptable to consider only the optimization of computer resources when producing a research code; one must also consider the availability and cost of the people necessary to maintain, modify and use the model as an investigative tool, and include these factors in defining the form of the model code. The new SKYHI model attempts to strike a balance between the optimization of the use of machine resources (CPU time, memory, disc and the optimal use of human resources (ability to understand code, ability to modify code, ability to perturb code to do experiments, ability to run code on different platforms. Two of the key features that make the new SKYHI code more usable and flexible are the archiving package and the user variable block. The archiving package is used to manage the writing of all archive files, which contain data for later analysis. The model-supplied user variable block allows the easy inclusion of any new variables needed for particular experiments.

  7. Numerical Modeling of Reactive Multiphase Flow for FCC and Hot Gas Desulfurization Circulating Fluidized Beds

    Energy Technology Data Exchange (ETDEWEB)

    Miller, Aubrey L. [WSU Research Corporation, Morgantown, WV (USA)

    2005-07-01

    This work was carried out to understand the behavior of the solid and gas phases in a CFB riser. Only the riser is modeled as a straight pipe. A model with linear algebraic approximation to solids viscosity of the form, {musubs} = 5.34{epsisubs}, ({espisubs} is the solids volume fraction) with an appropriate boundary condition at the wall obtained by approximate momentum balance solution at the wall to acount for the solids recirculation is tested against experimental results. The work done was to predict the flow patterns in the CFB risers from available experimental data, including data from a 7.5-cm-ID CFB riser at the Illinois Institute of Technology and data from a 20.0-cm-ID CFB riser at the Particulate Solid Research, Inc., facility. This research aims at modeling the removal of hydrogen sulfide from hot coal gas using zinc oxide as the sorbent in a circulating fluidized bed and in the process indentifying the parameters that affect the performance of the sulfidation reactor. Two different gas-solid reaction models, the unreacted shrinking core (USC) and the grain model were applied to take into account chemical reaction resistances. Also two different approaches were used to affect the hydrodynamics of the process streams. The first model takes into account the effect of micro-scale particle clustering by adjusting the gas-particle drag law and the second one assumes a turbulent core with pseudo-steady state boundary condition at the wall. A comparison is made with experimental results.

  8. Disseminated tumor cells in bone marrow and circulating tumor cells in blood of breast cancer patients: current state of detection and characterization.

    Science.gov (United States)

    Riethdorf, Sabine; Pantel, Klaus

    2008-01-01

    Despite the progress resulting from early detection and improved adjuvant therapy, the prognosis of breast cancer patients is still limited by the occurrence of distant metastases largely due to clinically occult micrometastases that remain undetected at primary diagnosis even by high-resolution imaging approaches. Recent research efforts have concentrated on the identification of additional parameters allowing individual risk assessment and stratification of patients for targeted therapies, since traditional prognostic factors are not sufficient to predict metastatic relapse and treatment decisions are still mainly based on statistical risk parameters. Highly sensitive and specific immunocytochemical and molecular assays now enable the detection and characterization of disseminated and circulating tumor cells (DTCs and CTCs, respectively) at the single cell level in bone marrow (BM) and peripheral blood, providing insights into the first crucial steps of the metastatic cascade. However, because of the still high variability of results in DTC/CTC detection, the necessity of standardized approaches will be discussed. A large number of studies showed that the presence of DTCs in BM has prognostic impact for primary breast cancer patients. DTCs are likely to escape from chemotherapy by maintaining a dormant nonproliferating state. There is also evidence for a stem cell-like phenotype of DTCs, probably contributing to the opportunity to escape from dormancy control and to start expansion to manifest metastases. Blood would also be an ideal source for the detection and monitoring of CTCs because of an easy noninvasive sampling procedure enabling repeated analyses. While prognostic significance of CTCs could be reliably demonstrated for metastatic breast cancer, studies to analyze the impact of CTCs in primary breast cancer patients and the potential to replace or supplement BM analysis are still ongoing. Furthermore, molecular characterization of CTCs might contribute

  9. Data Assimilation within the Advanced Circulation (ADCIRC) Modeling Framework for Hurricane Storm Surge Forecasting

    KAUST Repository

    Butler, T.

    2012-07-01

    Accurate, real-time forecasting of coastal inundation due to hurricanes and tropical storms is a challenging computational problem requiring high-fidelity forward models of currents and water levels driven by hurricane-force winds. Despite best efforts in computational modeling there will always be uncertainty in storm surge forecasts. In recent years, there has been significant instrumentation located along the coastal United States for the purpose of collecting data—specifically wind, water levels, and wave heights—during these extreme events. This type of data, if available in real time, could be used in a data assimilation framework to improve hurricane storm surge forecasts. In this paper a data assimilation methodology for storm surge forecasting based on the use of ensemble Kalman filters and the advanced circulation (ADCIRC) storm surge model is described. The singular evolutive interpolated Kalman (SEIK) filter has been shown to be effective at producing accurate results for ocean models using small ensemble sizes initialized by an empirical orthogonal function analysis. The SEIK filter is applied to the ADCIRC model to improve storm surge forecasting, particularly in capturing maximum water levels (high water marks) and the timing of the surge. Two test cases of data obtained from hindcast studies of Hurricanes Ike and Katrina are presented. It is shown that a modified SEIK filter with an inflation factor improves the accuracy of coarse-resolution forecasts of storm surge resulting from hurricanes. Furthermore, the SEIK filter requires only modest computational resources to obtain more accurate forecasts of storm surge in a constrained time window where forecasters must interact with emergency responders.

  10. Observed and modeled patterns of circulation in a semi-enclosed bay: Ria de Vigo (NW Iberia)

    Science.gov (United States)

    Pilczynski, Krzysztof; Dubert, Jesus; Nolasco, Rita; Barton, Des; Souto Torres, Carlos

    2016-04-01

    The Ría de Vigo, as a semi-enclosed bay, belonging to the area so-called Rias Baixas, located at the northern tip of the Iberian coastal upwelling system. The circulation of the Ria de Vigo, being one of the major areas of mussels production, has become the subject of intensive research. The Ria de Vigo behaves as a partially-mixed estuary with a two-layered residual circulation, and is influenced by water exchange with the surrounding ocean. During northerly (upwelling favorable) winds, water enters into the Ria through the northern mouth and leaves through the surface layer of the southern mouth, in a double layer circulation at this mouth. Nearly opposed situation occours during downwelling favourable wind periods. Numerical models have become useful tools to study the hydrology and circulation of the Ria de Vigo. In this research we used the ROMS - AGRIF model. The implementation of several nested domains to increase the spatial resolution (up to 150m resolution) allowed solving the interactions between Ria de Vigo and surrounding coastal ocean in a realistic way. We have obtained a detailed description of the circulation with good agreement between observational data (ADCP moorings at both mouths, and weekly hydrological cruises) and predicted currents, salinity and temperature fields. Two new patterns of circulation in the Ria are revealed by our research: -In particular conditions associated with northerly wind relaxation, there are two-layer circulation occurs in both mouths of the Ria, consisting of outflow and inflow though the surface and bottom layers. This situation happens in the absence of stratification during winter. -Also during winter, one-layer circulation in the southern mouth of the Ria (typically there are two layers) can occur during long periods of persistent and strong upwelling-favourable wind. Our research has provided a detailed study of the circulation and hydrology of the Ria de Vigo, explaining specifically different mechanisms of

  11. Comparative modeling of biological nutrient removal from landfill leachate using a circulating fluidized bed bioreactor (CFBBR).

    Science.gov (United States)

    Eldyasti, Ahmed; Andalib, Mehran; Hafez, Hisham; Nakhla, George; Zhu, Jesse

    2011-03-15

    Steady state operational data from a pilot scale circulating fluidized bed bioreactor (CFBBR) during biological treatment of landfill leachate, at empty bed contact times (EBCTs) of 0.49, and 0.41 d and volumetric nutrients loading rates of 2.2-2.6 kg COD/(m(3)d), 0.7-0.8 kg N/(m(3)d), and 0.014-0.016 kg P/(m(3)d), was used to calibrate and compare developed process models in BioWin(®) and AQUIFAS(®). BioWin(®) and AQUIFAS(®) were both capable of predicting most of the performance parameters such as effluent TKN, NH(4)-N, NO(3)-N, TP, PO(4)-P, TSS, and VSS with an average percentage error (APE) of 0-20%. BioWin(®) underpredicted the effluent BOD and SBOD values for various runs by 80% while AQUIFAS(®) predicted effluent BOD and SBOD with an APE of 50%. Although both calibrated models, confirmed the advantages of the CFBBR technology in treating the leachate of high volumetric loading and low biomass yields due to the long solid retention time (SRT), both BioWin(®) and AQUIFAS(®) predicted the total biomass and SRT of CFBBR based on active biomass only, whereas in the CFBBR runs both active as well as inactive biomass accumulated.

  12. ESTIMATING THE DEEP SOLAR MERIDIONAL CIRCULATION USING MAGNETIC OBSERVATIONS AND A DYNAMO MODEL: A VARIATIONAL APPROACH

    Energy Technology Data Exchange (ETDEWEB)

    Hung, Ching Pui; Jouve, Laurène; Brun, Allan Sacha [Laboratoire AIM Paris-Saclay, CEA/IRFU Université Paris-Diderot CNRS/INSU, F-91191 Gif-Sur-Yvette (France); Fournier, Alexandre [Institut de Physique du Globe de Paris, Sorbonne Paris Cité, Université Paris Diderot UMR 7154 CNRS, F-75005 Paris (France); Talagrand, Olivier [Laboratoire de météorologie dynamique, UMR 8539, Ecole Normale Supérieure, Paris Cedex 05 (France)

    2015-12-01

    We show how magnetic observations of the Sun can be used in conjunction with an axisymmetric flux-transport solar dynamo model in order to estimate the large-scale meridional circulation throughout the convection zone. Our innovative approach rests on variational data assimilation, whereby the distance between predictions and observations (measured by an objective function) is iteratively minimized by means of an optimization algorithm seeking the meridional flow that best accounts for the data. The minimization is performed using a quasi-Newton technique, which requires knowledge of the sensitivity of the objective function to the meridional flow. That sensitivity is efficiently computed via the integration of the adjoint flux-transport dynamo model. Closed-loop (also known as twin) experiments using synthetic data demonstrate the validity and accuracy of this technique for a variety of meridional flow configurations, ranging from unicellular and equatorially symmetric to multicellular and equatorially asymmetric. In this well-controlled synthetic context, we perform a systematic study of the behavior of our variational approach under different observational configurations by varying their spatial density, temporal density, and noise level, as well as the width of the assimilation window. We find that the method is remarkably robust, leading in most cases to a recovery of the true meridional flow to within better than 1%. These encouraging results are a first step toward using this technique to (i) better constrain the physical processes occurring inside the Sun and (ii) better predict solar activity on decadal timescales.

  13. Impact of Dust on Mars Surface Albedo and Energy Flux with LMD General Circulation Model

    Science.gov (United States)

    Singh, D.; Flanner, M.; Millour, E.; Martinez, G.

    2015-12-01

    Mars, just like Earth experience different seasons because of its axial tilt (about 25°). This causes growth and retreat of snow cover (primarily CO2) in Martian Polar regions. The perennial caps are the only place on the planet where condensed H2O is available at surface. On Mars, as much as 30% atmospheric CO2 deposits in each hemisphere depending upon the season. This leads to a significant variation on planet's surface albedo and hence effecting the amount of solar flux absorbed or reflected at the surface. General Circulation Model (GCM) of Laboratoire de Météorologie Dynamique (LMD) currently uses observationally derived surface albedo from Thermal Emission Spectrometer (TES) instrument for the polar caps. These TES albedo values do not have any inter-annual variability, and are independent of presence of any dust/impurity on surface. Presence of dust or other surface impurities can significantly reduce the surface albedo especially during and right after a dust storm. This change will also be evident in the surface energy flux interactions. Our work focuses on combining earth based Snow, Ice, and Aerosol Radiation (SNICAR) model with current state of GCM to incorporate the impact of dust on Martian surface albedo, and hence the energy flux. Inter-annual variability of surface albedo and planet's top of atmosphere (TOA) energy budget along with their correlation with currently available mission data will be presented.

  14. Acute effects of a large bolide impact simulated by a global atmospheric circulation model

    Science.gov (United States)

    Thompson, Starley L.; Crutzen, P. J.

    1988-01-01

    The goal is to use a global three-dimensional atmospheric circulation model developed for studies of atmospheric effects of nuclear war to examine the time evolution of atmospheric effects from a large bolide impact. The model allows for dust and NOx injection, atmospheric transport by winds, removal by precipitation, radiative transfer effects, stratospheric ozone chemistry, and nitric acid formation and deposition on a simulated Earth having realistic geography. Researchers assume a modest 2 km-diameter impactor of the type that could have formed the 32 km-diameter impact structure found near Manson, Iowa and dated at roughly 66 Ma. Such an impact would have created on the order of 5 x 10 to the 10th power metric tons of atmospheric dust (about 0.01 g cm(-2) if spread globally) and 1 x 10 to the 37th power molecules of NO, or two orders of magnitude more stratospheric NO than might be produced in a large nuclear war. Researchers ignore potential injections of CO2 and wildfire smoke, and assume the direct heating of the atmosphere by impact ejecta on a regional scale is not large compared to absorption of solar energy by dust. Researchers assume an impact site at 45 N in the interior of present day North America.

  15. Bayesian calibration of the Thermosphere-Ionosphere Electrodynamics General Circulation Model (TIE-GCM

    Directory of Open Access Journals (Sweden)

    A. D. Richmond

    2009-05-01

    Full Text Available In this paper, we demonstrate a procedure for calibrating a complex computer simulation model having uncertain inputs and internal parameters, with application to the NCAR Thermosphere-Ionosphere-Electrodynamics General Circulation Model (TIE-GCM. We compare simulated magnetic perturbations with observations at two ground locations for various combinations of calibration parameters. These calibration parameters are: the amplitude of the semidiurnal tidal perturbation in the height of a constant-pressure surface at the TIE-GCM lower boundary, the local time at which this maximises and the minimum night-time electron density. A fully Bayesian approach, that describes correlations in time and in the calibration input space is implemented. A Markov Chain Monte Carlo (MCMC approach leads to potential optimal values for the amplitude and phase (within the limitations of the selected data and calibration parameters but not for the minimum night-time electron density. The procedure can be extended to include additional data types and calibration parameters.

  16. Characteristics modeling for supercritical circulating fluidized bed boiler working in oxy-combustion technology

    Directory of Open Access Journals (Sweden)

    Balicki Adrian

    2014-06-01

    Full Text Available Among the technologies which allow to reduce greenhouse gas emission, mainly carbon dioxide, special attention deserves the idea of ‘zeroemission’ technology based on boilers working in oxy-combustion technology. In the paper the results of analyses of the influence of changing two quantities, namely oxygen share in oxidant produced in the air separation unit, and oxygen share in oxidant supplied to the furnace chamber on the selected characteristics of a steam boiler including the degree of exhaust gas recirculation, boiler efficiency and adiabatic flame temperature, was examined. Due to the possibility of the integration of boiler model with carbon dioxide capture, separation and storage installation, the subject of the analysis was also to determine composition of the flue gas at the outlet of a moisture condensation installation. Required calculations were made using a model of a supercritical circulating fluidized bed boiler working in oxy-combustion technology, which was built in a commercial software and in-house codes.

  17. Accuracy tests of radiation schemes used in hot Jupiter Global Circulation Models

    CERN Document Server

    Amundsen, David Skålid; Tremblin, Pascal; Manners, James; Hayek, Wolfgang; Mayne, N J; Acreman, David M

    2014-01-01

    The treatment of radiation transport in global circulation models (GCMs) is crucial to correctly describe Earth and exoplanet atmospheric dynamics processes. The two-stream approximation and correlated-$k$ method are currently state-of-the-art approximations applied in both Earth and hot Jupiter GCM radiation schemes to facilitate rapid calculation of fluxes and heating rates. Their accuracy have been tested extensively for Earth-like conditions, but verification of the methods' applicability to hot Jupiter-like conditions is lacking in the literature. We are adapting the UK Met Office GCM, the Unified Model (UM), for the study of hot Jupiters, and present in this work the adaptation of the Edwards-Slingo radiation scheme based on the two-stream approximation and the correlated-$k$ method. We discuss the calculation of absorption coefficients from high temperature line lists and highlight the large uncertainty in the pressure-broadened line widths. We compare fluxes and heating rates obtained with our adapted...

  18. Modeling the Circulation of Manila Bay: Assessing the Relative Magnitudes of Wind and Tide Forcing

    Directory of Open Access Journals (Sweden)

    Cesar Villanoy

    1997-12-01

    Full Text Available A two-dimensional circulation model of Manila Bay was used to determine the relative importance of wind and tide forcing. Tidal forcing was prescribed using tidal curves based on two diurnal (O1 and K1 and two semidiurnal (M2 and S2 components on both sides of the bay mouth. A slight amplitude increase towards the head of the bay was obtained, presumably due to shoaling effects. The high correlation between sea level variations at selected coastal tide stations and model results suggests the dependence on tidal forcing at the mouth. Strongest tidal velocities were found at the mouth and decreased towards the head of the bay. The wind-driven component of the flow using mean September 1995 wind forcing shows the presence of two asymmetrical, counter-rotating gyres. Comparison of wind and tidal kinetic energies indicates the dominance of the wind-driven component of the flow only in selected shallow areas adjacent to the coast.

  19. A model simulation of circulation in the Northeast Atlantic shelves and seas

    Science.gov (United States)

    1992-12-01

    A three-dimensional, primitive-equation simulation of the circulation in the northeast Atlantic shelves and seas, defined by 51°-76°N latitudes and 20°W-22°E longitudes, has been conducted for the period February-March 1988. The simulation was initialized from a 585-day quasi-equilibrium calculation and included realistic meteorological forcing, inflows/outflows across the open boundaries (inflow of the North Atlantic warm wate in particular), tides, coastal and Baltic discharges, and relaxation to wintertime climatology for model depths >500 m. The calculation is the first part of an overall effort to nest a high-resolution region for simulation of eddies and fronts in the Norwegian Coastal Current (NCC). This paper presents detailed simulation strategies and discusses results from the coarse-grid region to study the larger-scale model response induced by atmospheric forcing, so that its effects on flow dynamics in the nested grid can be better understood. The mean and variability of the simulated flow field are compared, whenever possible, with published observations. In particular, we examine in detail the simulated wind-induced response in the Skagerrak transport, which produces blocking and outbreak of the Skagerrak and North Sea waters. These transport variabilities can be expected to be important in the development of the NCC meanders and eddies further north.

  20. Liquid and Ice Cloud Microphysics in the CSU General Circulation Model. Part III: Sensitivity to Modeling Assumptions.

    Science.gov (United States)

    Fowler, Laura D.; Randall, David A.

    1996-03-01

    The inclusion of cloud microphysical processes in general circulation models makes it possible to study the multiple interactions among clouds, the hydrological cycle, and radiation. The gaps between the temporal and spatial scales at which such cloud microphysical processes work and those at which general circulation models presently function force climate modelers to crudely parameterize and simplify the various interactions among the different water species (namely, water vapor, cloud water, cloud ice, rain, and snow) and to use adjustable parameters to which large-scale models can be highly sensitive. Accordingly, the authors have investigated the sensitivity of the climate, simulated with the Colorado State University general circulation model, to various aspects of the parameterization of cloud microphysical processes and its interactions with the cumulus convection and radiative transfer parameterizations.The results of 120-day sensitivity experiments corresponding to perpetual January conditions have been compared with those of a control simulation in order to 1 ) determine the importance of advecting cloud water, cloud ice, rain, and snow at the temporal and spatial scale resolutions presently used in the model; 2) study the importance of the formation of extended stratiform anvils at the tops of cumulus towers, 3) analyze the role of mixed-phase clouds in determining the partitioning among cloud water, cloud ice, rain, and snow and, hence, their impacts on the simulated cloud optical properties; 4) evaluate the sensitivity of the atmospheric moisture budget and precipitation rates to a change in the fall velocities of rain and snow; 5) determine the model's sensitivity to the prescribed thresholds of autoconversion of cloud water to rain and cloud ice to snow; and 6) study the impact of the collection of supercooled cloud water by snow, as well as accounting for the cloud optical properties of snow.Results are presented in terms of 30-day mean differences

  1. Assessment of liver circulation by quantitative scintiangiography: Evaluation of the relative contribution of the hepatic arterial and portal venous blood flows to liver perfusion

    Energy Technology Data Exchange (ETDEWEB)

    Molino, G.; Squadrone, E.; Baccegal, M.; Magnani, C.

    1989-04-01

    Quantitative hepatic scintiangiography was previously used for evaluating the relative contribution of hepatic arterial and portal venous blood flows to the hepatic circulation. The present study compares 3 different procedures (automatic and manual integration, and slope fitting methods) for analyzing the hepatic time activity curves obtained after bolus i.v. injection of 370 MBq /sup 99m/Tc-diethylentriaminopentacetic acid. Twenty five subjects were studied: Five controls, ten cirrhotics, and ten portal hypertensive patients previously submitted to side to side portacaval anastomosis. The correspondence between results given by the different methods was satisfactory only in shunted patients, and the reproducibility of computed parameters was quite poor for all procedures. Accordingly, none of the methods can be considered as supporting reliable quantitative pathophysiological evaluations. However, the hepatic arterial/portal venous flow ratio was found to be increased in liver cirrhosis and in shunted patients and therefore, in spite of the limitations underlined before and of the absence of data on the reproducibility of consecutive injections, hepatic scintiangiography may be of some clinical utility.

  2. Circulating brain derived neurotrophic factor (BDNF) and frequency of BDNF positive T cells in peripheral blood in human ischemic stroke: Effect on outcome.

    Science.gov (United States)

    Chan, Adeline; Yan, Jun; Csurhes, Peter; Greer, Judith; McCombe, Pamela

    2015-09-15

    The aim of this study was to measure the levels of circulating BDNF and the frequency of BDNF-producing T cells after acute ischaemic stroke. Serum BDNF levels were measured by ELISA. Flow cytometry was used to enumerate peripheral blood leukocytes that were labelled with antibodies against markers of T cells, T regulatory cells (Tregs), and intracellular BDNF. There was a slight increase in serum BDNF levels after stroke. There was no overall difference between stroke patients and controls in the frequency of CD4(+) and CD8(+) BDNF(+) cells, although a subgroup of stroke patients showed high frequencies of these cells. However, there was an increase in the percentage of BDNF(+) Treg cells in the CD4(+) population in stroke patients compared to controls. Patients with high percentages of CD4(+) BDNF(+) Treg cells had a better outcome at 6months than those with lower levels. These groups did not differ in age, gender or initial stroke severity. Enhancement of BDNF production after stroke could be a useful means of improving neuroprotection and recovery after stroke.

  3. Intrinsic determinants and predictors of superovulatory yields in sheep: Circulating concentrations of reproductive hormones, ovarian status, and antral follicular blood flow.

    Science.gov (United States)

    Bartlewski, Pawel M; Seaton, Patricia; Franco Oliveira, Maria Emilia; Kridli, Rami T; Murawski, Maciej; Schwarz, Tomasz

    2016-07-01

    Hormonal ovarian superstimulation has contributed to small ruminant reproduction around the world, impacting genetic improvement and zoosanitary programs, contributing to the conservation of endangered species, and supporting other related biotechnologies. Advanced knowledge surrounding the superovulatory treatments in sheep has resulted in enhanced control of influencing factors and improved the protocols currently used. However, in spite of minimization of some adverse factors, superovulatory responses in ewes still remain variable, preventing the more widespread use of superovulation in commercial embryo transfer programs and reproductive research in this species. Recent evidence demonstrates that changes in antral follicular populations and blood supply, and circulating concentrations of certain reproductive hormones determined at the specific time points just before or during the superovulatory treatment are associated with superovulation success in ewes. This review attempts to compile the data from available literature to identify ovarian and hormonal determinants of the superovulatory outcome in ewes, which can be used to substantially improve the existing protocols and to reduce the extra cost and unnecessary stress imposed on poorly responding animals. An overview of most commonly used and some recently developed, FSH-based ovarian stimulation protocols is given at the outset to highlight variation in the frequency and timing of gonadotropin injections, estrus synchronization methods, and follicular wave synchronization and/or ovulation induction techniques during the superovulatory treatments in ewes.

  4. 3D modeling of GJ1214b's atmosphere: vertical mixing driven by an anti-Hadley circulation

    CERN Document Server

    Charnay, Benjamin; Leconte, Jérémy

    2015-01-01

    GJ1214b is a warm sub-Neptune transiting in front of a nearby M dwarf star. Recent observations indicate the presence of high and thick clouds or haze whose presence requires strong atmospheric mixing. In order to understand the transport and distribution of such clouds/haze, we study the atmospheric circulation and the vertical mixing of GJ1214b with a 3D General Circulation Model for cloud-free hydrogen-dominated atmospheres (metallicity of 1, 10 and 100 times the solar value) and for a water-dominated atmosphere. We analyze the effect of the atmospheric metallicity on the thermal structure and zonal winds. We also analyze the zonal mean meridional circulation and show that it corresponds to an anti-Hadley circulation in most of the atmosphere with upwelling at mid-latitude and downwelling at the equator in average. This circulation must be present on a large range of synchronously rotating exoplanets with strong impact on cloud formation and distribution. Using simple tracers, we show that vertical winds o...

  5. Modeling of urban heat island and its impacts on thermal circulations in the Beijing-Tianjin-Hebei region, China

    Science.gov (United States)

    Li, Mengmeng; Wang, Tijian; Xie, Min; Zhuang, Bingliang; Li, Shu; Han, Yong; Cheng, Nianliang

    2016-08-01

    Through regulating the land-atmosphere energy balance, urbanization plays an important role in modifying local circulations and cross-border transport of air pollutants. The Beijing-Tianjin-Hebei (BTH) metropolitan area in northern China is frequently influenced by complex atmospheric thermal circulations due to its special topography and geographic position. In this study, the Weather Research and Forecasting (WRF) model combined with remote sensing is used to explore the urbanization impacts on local circulations in the BTH region. The urban heat island (UHI) effect generated around Beijing and Tianjin shows complex interactions with local thermal circulations. Due to the combined effects of UHI and topography, the UHI circulation around Beijing and valley breeze at the southern slopes of Yan Mountain are coupled together to reinforce each other. At the coastal cities, the increased land/sea temperature gradient considerably accelerates the sea breeze along Bohai Bay and moves the sea breeze front further inland to reach as far as Beijing. This study may lay a foundation for the better understanding of air pollutant dispersion on complex terrain.

  6. Borehole model for simulation transport geothermal heat with heat pipe system and with forced circulation of heat carrier

    Directory of Open Access Journals (Sweden)

    Lenhard Richard

    2012-04-01

    Full Text Available In the call OPVaV-2008/2.2/01-SORO Operational Programme Research and Development - knowledge and technology transfer from research and development into practice (ITMS-26220220057, whose strategic goal is "Device to use low-potential geothermal heat without forced circulation of heat carrier deep in the well "in the Department of Energy laboratory techniques to construct a simulator of transport low potential of geothermal energy in comparative test-drilling in the laboratory. The article describes a device that was designed as a scale model of two deep boreholes each of which withdraws the earth's heat by heat transfer technology and heat carrier. Device using forced circulation of heat carrier will respond in the construction of equipment currently used to transport heat from deep borehole. As the heat carrier will be used CO2. Facilities without using forced circulation of heat carrier, the new technology, which will be used as heat carrier ammonia (NH3.

  7. A three-dimensional general circulation model with coupled chemistry for the middle atmosphere

    Science.gov (United States)

    Rasch, P. J.; Boville, B. A.; Brasseur, G. P.

    1995-05-01

    We document a new middle atmosphere general circulation model that includes ozone photochemistry. The dynamical model component is based on the NCAR middle atmosphere version of the Community Climate Model. The chemistry model component simulates the evolution of 24 chemically reactive gases. The horizontal resolution is approximately 3° in latitude and 6° in longitude. It includes 44 levels, with a maximum vertical grid spacing of about 2.5 km and a top level at around 75 km. The chemical model distinguishes between species where we judge transport to be critical and those for which it may be neglected. Nine longer-lived species (N2O, CH4, H2O, HNO3, N2O5, CO, ClONO2, HCl, and HOCl) and four chemical families (NOy, NOx, Ox and Clx) are advected. Concentrations of 15 species which are typically shorter-lived or are members of the chemical families are diagnosed using quasi-equilibrium assumptions ( O(1D), OH, Cl, O(3P), O3, HO2, NO2, ClO, NO, HNO4, NO3, N, OClO, Cl2O2, H2O2). Distributions for a number of other species are prescribed. Results are presented from a 2-year simulation, which include only gas phase photochemical reactions and in which the ozone distribution forecast from the chemistry module does not affect the radiative forcing of the dynamical fields. The calculated distributions of trace species and their seasonal evolution are often quite realistic, particularly in the northern hemisphere extratropics. Distributions of long-lived species such as N2O and CH4 correspond well to satellite observations. Some features, such as the double peak structure occurring during equinoxes, are not reproduced. The latitudinal variation and seasonal evolution of the ozone column abundance is quite realistic. The calculated vertical distribution of the ozone mixing ratio exhibits significant differences from measured values. The model underestimates significantly the ozone in the upper stratosphere (40 km) and in the extratropics, where the maximum values occur at

  8. General coarse-grained red blood cell models: I. Mechanics

    OpenAIRE

    FEDOSOV, DMITRY A.; Caswell, Bruce; Karniadakis, George E.

    2009-01-01

    We present a rigorous procedure to derive coarse-grained red blood cell (RBC) models, which lead to accurate mechanical properties of realistic RBCs. Based on a semi-analytic theory linear and non-linear elastic properties of the RBC membrane can be matched with those obtained in optical tweezers stretching experiments. In addition, we develop a nearly stress-free model which avoids a number of pitfalls of existing RBC models, such as non-biconcave equilibrium shape and dependence of RBC mech...

  9. Climate forcings and climate sensitivities diagnosed from atmospheric global circulation models

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, Bruce T. [Boston University, Department of Geography and Environment, Boston, MA (United States); Knight, Jeff R.; Ringer, Mark A. [Met Office Hadley Centre, Exeter (United Kingdom); Deser, Clara; Phillips, Adam S. [National Center for Atmospheric Research, Boulder, CO (United States); Yoon, Jin-Ho [University of Maryland, Cooperative Institute for Climate and Satellites, Earth System Science Interdisciplinary Center, College Park, MD (United States); Cherchi, Annalisa [Centro Euro-Mediterraneo per i Cambiamenti Climatici, and Istituto Nazionale di Geofisica e Vulcanologia, Bologna (Italy)

    2010-12-15

    Understanding the historical and future response of the global climate system to anthropogenic emissions of radiatively active atmospheric constituents has become a timely and compelling concern. At present, however, there are uncertainties in: the total radiative forcing associated with changes in the chemical composition of the atmosphere; the effective forcing applied to the climate system resulting from a (temporary) reduction via ocean-heat uptake; and the strength of the climate feedbacks that subsequently modify this forcing. Here a set of analyses derived from atmospheric general circulation model simulations are used to estimate the effective and total radiative forcing of the observed climate system due to anthropogenic emissions over the last 50 years of the twentieth century. They are also used to estimate the sensitivity of the observed climate system to these emissions, as well as the expected change in global surface temperatures once the climate system returns to radiative equilibrium. Results indicate that estimates of the effective radiative forcing and total radiative forcing associated with historical anthropogenic emissions differ across models. In addition estimates of the historical sensitivity of the climate to these emissions differ across models. However, results suggest that the variations in climate sensitivity and total climate forcing are not independent, and that the two vary inversely with respect to one another. As such, expected equilibrium temperature changes, which are given by the product of the total radiative forcing and the climate sensitivity, are relatively constant between models, particularly in comparison to results in which the total radiative forcing is assumed constant. Implications of these results for projected future climate forcings and subsequent responses are also discussed. (orig.)

  10. Computer modelling of anterior circulation stroke: Proof of concept in Cerebrovascular Occlusion