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Sample records for bf1 intersubtype circulating

  1. Identification of an HIV-1 BG Intersubtype Recombinant Form (CRF73_BG), Partially Related to CRF14_BG, Which Is Circulating in Portugal and Spain.

    Science.gov (United States)

    Fernández-García, Aurora; Delgado, Elena; Cuevas, María Teresa; Vega, Yolanda; Montero, Vanessa; Sánchez, Mónica; Carrera, Cristina; López-Álvarez, María José; Miralles, Celia; Pérez-Castro, Sonia; Cilla, Gustavo; Hinojosa, Carmen; Pérez-Álvarez, Lucía; Thomson, Michael M

    2016-01-01

    HIV-1 exhibits a characteristically high genetic diversity, with the M group, responsible for the pandemic, being classified into nine subtypes, 72 circulating recombinant forms (CRFs) and numerous unique recombinant forms (URFs). Here we characterize the near full-length genome sequence of an HIV-1 BG intersubtype recombinant virus (X3208) collected in Galicia (Northwest Spain) which exhibits a mosaic structure coincident with that of a previously characterized BG recombinant virus (9601_01), collected in Germany and epidemiologically linked to Portugal, and different from currently defined CRFs. Similar recombination patterns were found in partial genome sequences from three other BG recombinant viruses, one newly derived, from a virus collected in Spain, and two retrieved from databases, collected in France and Portugal, respectively. Breakpoint coincidence and clustering in phylogenetic trees of these epidemiologically-unlinked viruses allow to define a new HIV-1 CRF (CRF73_BG). CRF73_BG shares one breakpoint in the envelope with CRF14_BG, which circulates in Portugal and Spain, and groups with it in a subtype B envelope fragment, but the greatest part of its genome does not appear to derive from CRF14_BG, although both CRFs share as parental strain the subtype G variant circulating in the Iberian Peninsula. Phylogenetic clustering of partial pol and env segments from viruses collected in Portugal and Spain with X3208 and 9691_01 indicates that CRF73_BG is circulating in both countries, with proportions of around 2-3% Portuguese database HIV-1 isolates clustering with CRF73_BG. The fact that an HIV-1 recombinant virus characterized ten years ago as a URF has been shown to represent a CRF suggests that the number of HIV-1 CRFs may be much greater than currently known.

  2. Identification of an HIV-1 BG Intersubtype Recombinant Form (CRF73_BG, Partially Related to CRF14_BG, Which Is Circulating in Portugal and Spain.

    Directory of Open Access Journals (Sweden)

    Aurora Fernández-García

    Full Text Available HIV-1 exhibits a characteristically high genetic diversity, with the M group, responsible for the pandemic, being classified into nine subtypes, 72 circulating recombinant forms (CRFs and numerous unique recombinant forms (URFs. Here we characterize the near full-length genome sequence of an HIV-1 BG intersubtype recombinant virus (X3208 collected in Galicia (Northwest Spain which exhibits a mosaic structure coincident with that of a previously characterized BG recombinant virus (9601_01, collected in Germany and epidemiologically linked to Portugal, and different from currently defined CRFs. Similar recombination patterns were found in partial genome sequences from three other BG recombinant viruses, one newly derived, from a virus collected in Spain, and two retrieved from databases, collected in France and Portugal, respectively. Breakpoint coincidence and clustering in phylogenetic trees of these epidemiologically-unlinked viruses allow to define a new HIV-1 CRF (CRF73_BG. CRF73_BG shares one breakpoint in the envelope with CRF14_BG, which circulates in Portugal and Spain, and groups with it in a subtype B envelope fragment, but the greatest part of its genome does not appear to derive from CRF14_BG, although both CRFs share as parental strain the subtype G variant circulating in the Iberian Peninsula. Phylogenetic clustering of partial pol and env segments from viruses collected in Portugal and Spain with X3208 and 9691_01 indicates that CRF73_BG is circulating in both countries, with proportions of around 2-3% Portuguese database HIV-1 isolates clustering with CRF73_BG. The fact that an HIV-1 recombinant virus characterized ten years ago as a URF has been shown to represent a CRF suggests that the number of HIV-1 CRFs may be much greater than currently known.

  3. Viral replication is enhanced by an HIV-1 intersubtype recombination-derived Vpu protein

    Directory of Open Access Journals (Sweden)

    Salomón Horacio

    2010-10-01

    Full Text Available Abstract Background Multiple HIV-1 intersubtype recombinants have been identified in human populations. Previous studies from our lab group have shown that the epidemic in Argentina is characterized by the high prevalence of a circulating recombinant form, CRF12_BF, and many related BF recombinant forms. In these genomic structures a recombination breakpoint frequently involved the vpu coding region. Due to the scarce knowledge of Vpu participation in the virion release process and its impact on pathogenesis and of the functional capacities of intersubtype recombinant Vpu proteins, the aim of this work was to perform a comparative analysis on virion release capacity and relative replication capacity among viral variants harboring either a BF recombinant Vpu or a subtype B Vpu. Results Our results showed that BF recombinant Vpu was associated to an increased viral particles production when compared to WT B variant in tetherin-expressing cell lines. This observation was tested in the context of a competition assay between the above mentioned variants. The results showed that the replication of the BF Vpu-harboring variant was more efficient in cell cultures than subtype B, reaching a higher frequency in the viral population in a short period of time. Conclusion This study showed that as a result of intersubtype recombination, a structurally re-organized HIV-1 Vpu has an improved in vitro capacity of enhancing viral replication, and provides evidence of the changes occurring in this protein function that could play an important role in the successful spread of intersubtype recombinant variants.

  4. Influence of sequence identity and unique breakpoints on the frequency of intersubtype HIV-1 recombination

    Directory of Open Access Journals (Sweden)

    Abreha Measho

    2006-12-01

    Full Text Available Abstract Background HIV-1 recombination between different subtypes has a major impact on the global epidemic. The generation of these intersubtype recombinants follows a defined set of events starting with dual infection of a host cell, heterodiploid virus production, strand transfers during reverse transcription, and then selection. In this study, recombination frequencies were measured in the C1-C4 regions of the envelope gene in the presence (using a multiple cycle infection system and absence (in vitro reverse transcription and single cycle infection systems of selection for replication-competent virus. Ugandan subtypes A and D HIV-1 env sequences (115-A, 120-A, 89-D, 122-D, 126-D were employed in all three assay systems. These subtypes co-circulate in East Africa and frequently recombine in this human population. Results Increased sequence identity between viruses or RNA templates resulted in increased recombination frequencies, with the exception of the 115-A virus or RNA template. Analyses of the recombination breakpoints and mechanistic studies revealed that the presence of a recombination hotspot in the C3/V4 env region, unique to 115-A as donor RNA, could account for the higher recombination frequencies with the 115-A virus/template. Single-cycle infections supported proportionally less recombination than the in vitro reverse transcription assay but both systems still had significantly higher recombination frequencies than observed in the multiple-cycle virus replication system. In the multiple cycle assay, increased replicative fitness of one HIV-1 over the other in a dual infection dramatically decreased recombination frequencies. Conclusion Sequence variation at specific sites between HIV-1 isolates can introduce unique recombination hotspots, which increase recombination frequencies and skew the general observation that decreased HIV-1 sequence identity reduces recombination rates. These findings also suggest that the majority of

  5. Influence of sequence identity and unique breakpoints on the frequency of intersubtype HIV-1 recombination

    Science.gov (United States)

    Baird, Heather A; Gao, Yong; Galetto, Román; Lalonde, Matthew; Anthony, Reshma M; Giacomoni, Véronique; Abreha, Measho; Destefano, Jeffrey J; Negroni, Matteo; Arts, Eric J

    2006-01-01

    Background HIV-1 recombination between different subtypes has a major impact on the global epidemic. The generation of these intersubtype recombinants follows a defined set of events starting with dual infection of a host cell, heterodiploid virus production, strand transfers during reverse transcription, and then selection. In this study, recombination frequencies were measured in the C1-C4 regions of the envelope gene in the presence (using a multiple cycle infection system) and absence (in vitro reverse transcription and single cycle infection systems) of selection for replication-competent virus. Ugandan subtypes A and D HIV-1 env sequences (115-A, 120-A, 89-D, 122-D, 126-D) were employed in all three assay systems. These subtypes co-circulate in East Africa and frequently recombine in this human population. Results Increased sequence identity between viruses or RNA templates resulted in increased recombination frequencies, with the exception of the 115-A virus or RNA template. Analyses of the recombination breakpoints and mechanistic studies revealed that the presence of a recombination hotspot in the C3/V4 env region, unique to 115-A as donor RNA, could account for the higher recombination frequencies with the 115-A virus/template. Single-cycle infections supported proportionally less recombination than the in vitro reverse transcription assay but both systems still had significantly higher recombination frequencies than observed in the multiple-cycle virus replication system. In the multiple cycle assay, increased replicative fitness of one HIV-1 over the other in a dual infection dramatically decreased recombination frequencies. Conclusion Sequence variation at specific sites between HIV-1 isolates can introduce unique recombination hotspots, which increase recombination frequencies and skew the general observation that decreased HIV-1 sequence identity reduces recombination rates. These findings also suggest that the majority of intra- or intersubtype A

  6. Intersubtype Reassortments of H5N1 Highly Pathogenic Avian Influenza Viruses Isolated from Quail.

    Science.gov (United States)

    Nguyen, Tinh Huu; Than, Van Thai; Thanh, Hien Dang; Hung, Vu-Khac; Nguyen, Duc Tan; Kim, Wonyong

    2016-01-01

    H5N1 highly pathogenic avian influenza (HPAI) viruses are considered a threat to national animal industries, causing production losses and high mortality in domestic poultry. In recent years, quail has become a popular terrestrial poultry species raised for production of meat and eggs in Asia. In this study, to better understand the roles of quail in H5N1 viral evolution, two H5N1-positive samples, designated A/quail/Vietnam/CVVI-49/2010 (CVVI-49/2010) and A/quail/Vietnam/CVVI-50/2014 (CVVI-50/2014), were isolated from quail during H5N1 outbreaks in Vietnam, and their whole genome were analyzed. The phylogenetic analysis reveals new evolutionary variation in the worldwide H5N1 viruses. The quail HA genes were clustered into clades 1.1.1 (CVVI-49/2010) and clade 2.3.2.1c (CVVI-50/2014), which may have evolved from viruses circulating from chickens and/or ducks in Cambodia, mainland of China, Taiwan, Indonesia, and South Korea in recent years. Interestingly, the M2 gene of the CVVI-49/2010 strain contained amino acid substitutions at position 26L-I and 31S-N that are related to amantadine-resistance. In particular, the CVVI-50/2014 strain revealed evidence of multiple intersubtype reassortment events between virus clades 2.3.2.1c, 2.3.2.1b, and 2.3.2.1a. Data from this study supports the possible role of quail as an important intermediate host in avian influenza virus evolution. Therefore, additional surveillance is needed to monitor these HPAI viruses both serologically and virologically in quail.

  7. LINK codes TRAC-BF1/PARCSv2.7 in LINUX without external communication interface; Acoplamiento de los codigos TRAC-BF1/PARCSv2.7 en Linux sin interfaz externa de comunicacion

    Energy Technology Data Exchange (ETDEWEB)

    Barrachina, T.; Garcia-Fenoll, M.; Abarca, A.; Miro, R.; Verdu, G.; Concejal, A.; Solar, A.

    2014-07-01

    The TRAC-BF1 code is still widely used by the nuclear industry for safety analysis. The plant models developed using this code are highly validated, so it is advisable to continue improving this code before migrating to another completely different code. The coupling with the NRC neutronic code PARCSv2.7 increases the simulation capabilities in transients in which the power distribution plays an important role. In this paper, the procedure for the coupling of TRAC-BF1 and PARCSv2.7 codes without PVM and in Linux is presented. (Author)

  8. Containment response to a main steam-line break using CONTAIN, RIS, and TRAC/BF1

    Energy Technology Data Exchange (ETDEWEB)

    Smith, K.; Baratta, A. (Pennsylvania State Univ., University Park (United States)); Talens, H. (N.V. KEMA, Arnhem (Netherlands))

    1991-01-01

    This paper summarizes containment analyses performed using the CONTAIN, RIS, and TRAC/BF1 computer codes. Although each of these codes is a containment response code, they differ in their approaches to modeling the various phenomena that occur in the containment. The work was initiated to evaluate the ability of these codes to predict containment response during a main steam-line break (MSLB). This project expands on previous analysis performed by KEMA using the RIS and TRAC/BF1 codes to include CONTAIN results. In the course of this project, all three codes demonstrated their usefulness. Although all three codes predicted satisfactory results, the RIS and CONTAIN codes seem best suited for this type of transient. The TRAC/BF1 code should be used for transients where the interactions between the primary and containment system are though to be large.

  9. Comparative study of different models of transportation of boron in the codes Thermohydraulic TRAC-BF1, TRACE and RELAP; Estudio Comparativo de Diferentes Modelos de Transporte de Boro en los Codigos Termohidraulicos TRAC-BF1, TRACE y RELAP

    Energy Technology Data Exchange (ETDEWEB)

    Jambrina, A.; Solar, A.; Barrachina, T.; Miro, R.; Verdu, G.; Concejal, A.

    2013-07-01

    In BWR the importance of boron transport lies in maintaining the core integrity during ATWS-kind severe accidents in which under certain circumstances a boron injection is required. The boron transport model implemented in TRAC-BF1 code is based on a first order accurate upwind difference scheme. Four numerical schemes that solve the boron transport model have been analyzed and compared with the analytical solution that provides the Burgers equation: first order Upwind, second order Godunov, second-order modified Godunov and a third-order QUICKEST using the ULTIMATE universal limiter. The modified Godunov scheme has been implemented in TRAC-BF1 source code. The results using these new schemes are presented in this paper.

  10. Implementación del modelo de decay heat ANSI/ ANS-5.1-2005 EN TRAC-BF1

    OpenAIRE

    SOLER MARTÍNEZ, MARÍA DESAMPARADOS; Barrachina Celda, Teresa María; Miró Herrero, Rafael; Concejal, A.; Melara, J.; Verdú Martín, Gumersindo Jesús

    2012-01-01

    En este artículo se muestran los resultados de la implementación del modelo de calor residual (Decay Heat) ANSI/ANS-5.1 2005 en el código termohidráulico TRAC-BF1. Los modelos para el cálculo del calor residual en el código TRAC-BF1 se corresponden con el estándar ANS 1973, por defecto, y con el estándar ANS 1979, si es seleccionado por parte del usuario. Con la entrada en vigor del estándar ANS 1994 y, su posterior revisión, el estándar ANS 2005 los modelos que presenta TRAC-...

  11. BF-1--a novel selective 5-HT2B receptor antagonist blocking neurogenic dural plasma protein extravasation in guinea pigs.

    Science.gov (United States)

    Schmitz, Beate; Ullmer, Christoph; Segelcke, Daniel; Gwarek, Mirella; Zhu, Xin-Ran; Lübbert, Hermann

    2015-03-15

    Serotonin 5-HT2B receptor antagonists have been proposed as migraine prophylactic drugs, but previously available 5-HT2B receptor antagonists displayed multiple monoaminergic side effects and had to be withdrawn from the market. Here, we set out to identify a novel antagonist with high affinity and selectivity towards 5-HT2B receptors. To test the affinity of new compounds towards various receptors, we generated a broad series of cells functionally coupling human monoaminergic receptors to luciferase. Using the cell lines we revealed pimethixene (1-methyl-4-(9H-thioxanthen-9-ylidene)piperidine) as highly potent, albeit non-selective 5-HT2B receptor antagonist and optimized its chemical structure to create highly potent and selective 5-HT2B receptor antagonists. We selected the methoxythioxanthene BF-1 for further analysis. In comparison to pimethixene, it lacked high affinities to 5-HT1A, 5-HT2A, 5-HT2C, histamine H1, dopamine D1 and D2 as well as muscarinic M1 and M2 receptors. BF-1 was tested as potential migraine prophylactic drug by blocking meta-chlorophenylpiperazine, (mCPP) or BW723C86 (5-((thiophen-2-yl)methoxy)-α-methyltryptamine) induced neurogenic dural plasma protein extravasation in a guinea pig model that may resemble a migraine attack. BF-1 was significantly more potent in this assay compared to the well know non-selective 5-HT2B antagonists, methysergide ((6aR,9R)-N-[(2S)-1-Hydroxybutan-2-yl]-4,7-dimethyl-6,6a,8,9-tetrahydroindolo[4,3-fg]quinoline-9-carboxamide) or pizotifen (4-(1-methyl-4-piperidylidine)-9,10-dihydro-4H-benzo-[4,5]cyclohepta[1,2]-thiophene). Therefore, we propose BF-1 as a new compound that may be developed for prophylactic migraine treatment without the typical monoaminergic side effects.

  12. Expression of the ctenophore Brain Factor 1 forkhead gene ortholog (ctenoBF-1) mRNA is restricted to the presumptive mouth and feeding apparatus: implications for axial organization in the Metazoa

    Science.gov (United States)

    Yamada, Atsuko; Martindale, Mark Q.

    2002-01-01

    Ctenophores are thoroughly modern animals whose ancestors are derived from a separate evolutionary branch than that of other eumetazoans. Their major longitudinal body axis is the oral-aboral axis. An apical sense organ, called the apical organ, is located at the aboral pole and contains a highly innervated statocyst and photodetecting cells. The apical organ integrates sensory information and controls the locomotory apparatus of ctenophores, the eight longitudinal rows of ctene/comb plates. In an effort to understand the developmental and evolutionary organization of axial properties of ctenophores we have isolated a forkhead gene from the Brain Factor 1 (BF-1) family. This gene, ctenoBF-1, is the first full-length nuclear gene reported from ctenophores. This makes ctenophores the most basal metazoan (to date) known to express definitive forkhead class transcription factors. Orthologs of BF-1 in vertebrates, Drosophila, and Caenorhabditis elegans are expressed in anterior neural structures. Surprisingly, in situ hybridizations with ctenoBF-1 antisense riboprobes show that this gene is not expressed in the apical organ of ctenophores. CtenoBF-1 is expressed prior to first cleavage. Transcripts become localized to the aboral pole by the 8-cell stage and are inherited by ectodermal micromeres generated from this region at the 16- and 32-cell stages. Expression in subsets of these cells persists and is seen around the edge of the blastopore (presumptive mouth) and in distinct ectodermal regions along the tentacular poles. Following gastrulation, stomodeal expression begins to fade and intense staining becomes restricted to two distinct domains in each tentacular feeding apparatus. We suggest that the apical organ is not homologous to the brain of bilaterians but that the oral pole of ctenophores corresponds to the anterior pole of bilaterian animals.

  13. Full-length characterization of A1/D intersubtype recombinant genomes from a therapy-induced HIV type 1 controller during acute infection and his noncontrolling partner

    DEFF Research Database (Denmark)

    Fomsgaard, Anders; Vinner, Lasse; Therrien, Dominic;

    2008-01-01

    homology in shared regions. Four of seven crossover points were identical; however, the env gene from UG1 was subtype D, but A1 in DK1. Both viruses encoded proteins of the expected length and replicated equally well in vitro. DK1 and UG1 shared the HLA-A02 tissue type. HLA-A02-restricted CD8(+) T cell IFN...... after 1 year in Uganda. Following transient antiretroviral therapy DK1 maintained undetectable viral load for more than 10 years. His Ugandan wife (UG1) developed high viral load. HIV-1 sequences from both individuals were compared by bootscanning for recombination break points. Diversity plots......-gamma IC-FACS response in DK1 was detected against only one (Pol(476)) of 23 conserved epitopes. Neutralizing antibodies were induced only to the homologous isolate. These results indicate an A1D intersubtype recombination or transmission of a minor variant. Transient early antiretroviral therapy may have...

  14. Fetal Circulation

    Science.gov (United States)

    ... Peripheral Artery Disease Venous Thromboembolism Aortic Aneurysm More Fetal Circulation Updated:Oct 18,2016 click to enlarge The ... fetal heart. These two bypass pathways in the fetal circulation make it possible for most fetuses to survive ...

  15. Nearshore circulation

    NARCIS (Netherlands)

    Battjes, J.A.; Sobey, R.J.; Stive, M.J.F.

    1990-01-01

    Shelf circulation is driven primarily by wind- and tide-induced forces. It is laterally only weakly constrained so that the geostrophic (Coriolis) acceleration is manifest in the response. Nearshore circulation on the other hand is dominated by wave-induced forces associated with shallow-water. wave

  16. Circulation economics

    DEFF Research Database (Denmark)

    Ingebrigtsen, Stig; Jakobsen, Ove

    2006-01-01

    Purpose - This paper is an attempt to advance the critical discussion regarding environmental and societal responsibility in economics and business. Design/methodology/approach - The paper presents and discusses as a holistic, organic perspective enabling innovative solutions to challenges...... concerning the responsible and efficient use of natural resources and the constructive interplay with culture. To reach the goal of sustainable development, the paper argues that it is necessary to make changes in several dimensions in mainstream economics. This change of perspective is called a turn towards...... presupposes a perspective integrating economic, natural and cultural values. Third, to organize the interplay between all stakeholders we introduce an arena for communicative cooperation. Originality/value - The paper concludes that circulation economics presupposes a change in paradigm, from a mechanistic...

  17. Emergence of recombinant forms in geographic regions with co-circulating HIV subtypes in the dynamic HIV-1 epidemic

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Ming [Los Alamos National Laboratory; Letiner, Thomas K [Los Alamos National Laboratory; Korber, Bette T [Los Alamos National Laboratory; Foley, Brian [Los Alamos National Laboratory

    2009-01-01

    We have reexamined the subtype designations of {approx}10,000 subtype A, B, C, G, and AG, BC, BF recombinant sequences, and compared the results of the new analysis with their published designations. Intersubtype recombinants dominate HIV epidemics in three different geographical regions. The circulating recombinant from (CRF) CRF02-AG, common in West Central Africa, appears to result from a recombination event that occurred early in the divergence between subtypes A and G, although additional more recent recombination events may have contributed to the breakpoint pattern in this recombinant lineage as well. The Chinese recombinant epidemic strains CRF07 and CRF08, in contrast, result from recent recombinations between more contemporary strains. Nevertheless, CRF07 and CRF08 contributed to many subsequent recombination events. The BF recombinant epidemics in two HIV-1 epicenters in South America are not independent and BF epidemics in South America have an unusually high fraction of unique recombinant forms (URFs) that have each been found only once and carry distinctive breakpoints. Taken together, these analyses reveal a complex and dynamic picture of the current HIV-1 epidemic, and suggest a means of grouping and tracking relationships between viruses through preservation of shared breakpints.

  18. Microwave circulator design

    CERN Document Server

    Linkhart, Douglas K

    2014-01-01

    Circulator design has advanced significantly since the first edition of this book was published 25 years ago. The objective of this second edition is to present theory, information, and design procedures that will enable microwave engineers and technicians to design and build circulators successfully. This resource contains a discussion of the various units used in the circulator design computations, as well as covers the theory of operation. This book presents numerous applications, giving microwave engineers new ideas about how to solve problems using circulators. Design examples are provided, which demonstrate how to apply the information to real-world design tasks.

  19. Mountains and Tropical Circulation

    Science.gov (United States)

    Naiman, Z.; Goodman, P. J.; Krasting, J. P.; Malyshev, S.; Russell, J. L.; Stouffer, R. J.

    2015-12-01

    Observed tropical convection exhibits zonal asymmetries that strongly influence spatial precipitation patterns. The drivers of changes to this zonally-asymmetric Walker circulation on decadal and longer timescales have been the focus of significant recent research. Here we use two state-of-the-art earth system models to explore the impact of earth's mountains on the Walker circulation. When all land-surface topography is removed, the Walker circulation weakens by 33-59%. There is a ~30% decrease in global, large-scale upward vertical wind velocities in the middle of the troposphere, but only minor changes in global average convective mass flux, precipitation, surface and sea-surface temperatures. The zonally symmetric Hadley circulation is also largely unchanged. Following the spatial pattern of changes to large-scale vertical wind velocities, precipitation becomes less focused over the tropics. The weakening of the Walker circulation, but not the Hadley circulation, is similar to the behavior of climate models during radiative forcing experiments: in our simulations, the weakening is associated with changes in vertical wind velocities, rather than the hydrologic cycle. These results indicate suggest that mountain heights may significantly influence the Walker circulation on geologic time scales, and observed changes in tropical precipitation over millions of years may have been forced by changes in tropical orography.

  20. Learning Circulant Sensing Kernels

    Science.gov (United States)

    2014-03-01

    learned dictionaries. Examples of analytic dictionaries include the discrete cosine basis, various wavelets bases , as well as tight frames. Some of them...Compressive sensing based high resolution channel estimation for OFDM system. To appear in IEEE Journal of Selected Topics in Signal Processing, Special...theoretical and computational properties to a (partial) circulant matrix of the same size, our discussions below are based exclusively on the circulant

  1. Gaussian Fibonacci Circulant Type Matrices

    Directory of Open Access Journals (Sweden)

    Zhaolin Jiang

    2014-01-01

    Full Text Available Circulant matrices have become important tools in solving integrable system, Hamiltonian structure, and integral equations. In this paper, we prove that Gaussian Fibonacci circulant type matrices are invertible matrices for n>2 and give the explicit determinants and the inverse matrices. Furthermore, the upper bounds for the spread on Gaussian Fibonacci circulant and left circulant matrices are presented, respectively.

  2. Circulant Double Coverings of a Circulant Graph of Valency Five

    Institute of Scientific and Technical Information of China (English)

    Rong Quan FENG; Jin Ho KWAK

    2007-01-01

    Enumerating the isomorphism classes of several types of graph covering projections is one of the central research topics in enumerative topological graph theory. A covering of G is called circulant if its covering graph is circulant. Recently, the authors [Discrete Math., 277, 73-85 (2004)]enumerated the isomorphism classes of circulant double coverings of a certain type, called a typicalcovering, and showed that no double covering of a circulant graph of valency three is circulant. Also, in [Graphs and Combinatorics, 21, 386-400 (2005)], the isomorphism classes of circulant double coverings of a circulant graph of valency four are enumerated. In this paper, the isomorphism classes of circulant double coverings of a circulant graph of valency five are enumerated.

  3. Kernels in circulant digraphs

    Directory of Open Access Journals (Sweden)

    R. Lakshmi

    2014-06-01

    Full Text Available A kernel $J$ of a digraph $D$ is an independent set of vertices of $D$ such that for every vertex $w,in,V(D,setminus,J$ there exists an arc from $w$ to a vertex in $J.$ In this paper, among other results, a characterization of $2$-regular circulant digraph having a kernel is obtained. This characterization is a partial solution to the following problem: Characterize circulant digraphs which have kernels; it appeared in the book {it Digraphs - theory, algorithms and applications}, Second Edition, Springer-Verlag, 2009, by J. Bang-Jensen and G. Gutin.

  4. The fetal circulation.

    Science.gov (United States)

    Kiserud, Torvid; Acharya, Ganesh

    2004-12-30

    Accumulating data on the human fetal circulation shows the similarity to the experimental animal physiology, but with important differences. The human fetus seems to circulate less blood through the placenta, shunt less through the ductus venosus and foramen ovale, but direct more blood through the lungs than the fetal sheep. However, there are substantial individual variations and the pattern changes with gestational age. The normalised umbilical blood flow decreases with gestational age, and, at 28 to 32 weeks, a new level of development seems to be reached. At this stage, the shunting through the ductus venosus and the foramen ovale reaches a minimum, and the flow through the lungs a maximum. The ductus venosus and foramen ovale are functionally closely related and represent an important distributional unit for the venous return. The left portal branch represents a venous watershed, and, similarly, the isthmus aorta an arterial watershed. Thus, the fetal central circulation is a very flexible and adaptive circulatory system. The responses to increased afterload, hypoxaemia and acidaemia in the human fetus are equivalent to those found in animal studies: increased ductus venosus and foramen ovale shunting, increased impedance in the lungs, reduced impedance in the brain, increasingly reversed flow in the aortic isthmus and a more prominent coronary blood flow.

  5. 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

  6. Cereral Circulation in Preeclampsia

    Directory of Open Access Journals (Sweden)

    A. A. Ivshin

    2008-01-01

    Full Text Available Objective: to evaluate the possibilities of using transcranial Doppler study in pregnant women and pueperas with preeclamp-sia. Subjects and methods. Two hundred and thirty-two pregnant women diagnosed as having varying preeclampsia were prospectively studied. A comparison group comprised 90 apparently healthy women in the third trimester of pregnancy. All the respondents underwent transcranial duplex scanning of the medial cerebral artery with the linear velocity values being determined. A number of the values reflecting the level of perfusion and intracranial pressures, hydrodynamic resistance in the system, cerebrovascular responsiveness and the state of the vascular wall were calculated. Correlation analysis was made between the parameters of cerebral circulation and the severity of preeclampsia, proteinuria, the severity of hydrops, and the parameters of central and peripheral hemodynamics. Results. The findings suggest that there is impaired cerebral perfusion in pregnant women and puerperas with varying preeclampsia, the severity of cerebral circulatory disorders being in proportion with that of preeclampsia. There is a close correlation between cerebral circulation and the individual criteria determining the severity of preeclampsia. The linear values of the Doppler spectrum, namely linear flow characteristics, are prognos-tically most significant. Conclusion. The introduction of transcranial Doppler study into obstetric care has permitted the authors not only to study cerebral circulatory disorders in healthy and pregnant women and puerperas with preeclampia in detail, but also to establish a number of highly significant prognostic criteria for the severity of this life-threatening complication of gestation. The results of transcranial Doppler study assist practitioners in timely and accurately solving the problems in the diagnosis of preeclampsia and in evaluating its severity. Cerebral circulatory values may be successfully used to

  7. Resolvability in Circulant Graphs

    Institute of Scientific and Technical Information of China (English)

    Muhammad SALMAN; Imran JAVAID; Muhammad Anwar CHAUDHRY

    2012-01-01

    A set W of the vertices of a connected graph G is called a resolving set for G if for every two distinct vertices u,v ∈ V(G) there is a vertex w ∈ W such that d(u,w) ≠ d(v,w).A resolving set of minimum cardinality is called a metric basis for G and the number of vertices in a metric basis is called the metric dimension of G,denoted by dim(G).For a vertex u of G and a subset S of V(G),the distance between u and S is the number mins∈s d(u,s).A k-partition H ={S1,S2,...,Sk} of V(G) is called a resolving partition if for every two distinct vertices u,v ∈ V(G) there is a set Si in Π such that d(u,Si) ≠ d(v,Si).The minimum k for which there is a resolving k-partition of V(G) is called the partition dimension of G,denoted by pd(G).The circulant graph is a graph with vertex set Zn,an additive group ofintegers modulo n,and two vertices labeled i and j adjacent if and only if i - j (mod n) ∈ C,where C C Zn has the property that C =-C and 0(∈) C.The circulant graph is denoted by Xn,△ where A =|C|.In this paper,we study the metric dimension of a family of circulant graphs Xn,3 with connection set C ={1,-n/2,n - 1} and prove that dim(Xn,3) is independent of choice of n by showing that 3 for all n =0 (mod 4),dim(X,n,3) ={ 4 for all n =2 (mod 4).We also study the partition dimension of a family of circulant graphs Xn,4 with connection set C ={±1,±2} and prove that pd(Xn,4) is independent of choice of n and show that pd(X5,4) =5 and 3 forall odd n≥9,pd(Xn,4) ={ 4 for all even n ≥ 6 and n =7.

  8. North Atlantic Circulation

    Science.gov (United States)

    Molinari, R.; Bryan, K.; Schott, F.

    The intensity of the North Atlantic winddriven and thermohaline circulation and the close proximity of many oceanographic installations make the North Atlantic a particularly favored region of the world ocean from the standpoint of research in ocean circulation. Recent increases in available data and advances in numerical modeling techniques served as the impetus to convene a joint workshop of modelers and observers working on the North Atlantic with the Scientific Committee on Oceanic Research (SCOR) Working Group (WG) 68 (“North Atlantic Circulation”). Goals of the workshop were to provide an update on data sets and models and to discuss the poleward heat flux problem and possible monitoring strategies. The joint Workshop/SCOR WG-68 meeting was convened by F. Schott (chairman of the working group; Rosenstiel School of Marine and Atmospheric Science, Miami, Fla.), K. Bryan (National Oceanic and Atmospheric Administration/ Geophysical Fluid Dynamics Laboratory (NOAA/GFDL)), and R. Molinari (NOAA/Atlantic Oceanographic and Meteorological Laboratory (NOAA/AOML)).

  9. Circulation of Stars

    Science.gov (United States)

    Boitani, P.

    2016-01-01

    Since the dawn of man, contemplation of the stars has been a primary impulse in human beings, who proliferated their knowledge of the stars all over the world. Aristotle sees this as the product of primeval and perennial “wonder” which gives rise to what we call science, philosophy, and poetry. Astronomy, astrology, and star art (painting, architecture, literature, and music) go hand in hand through millennia in all cultures of the planet (and all use catasterisms to explain certain phenomena). Some of these developments are independent of each other, i.e., they take place in one culture independently of others. Some, on the other hand, are the product of the “circulation of stars.” There are two ways of looking at this. One seeks out forms, the other concentrates on the passing of specific lore from one area to another through time. The former relies on archetypes (for instance, with catasterism), the latter constitutes a historical process. In this paper I present some of the surprising ways in which the circulation of stars has occurred—from East to West, from East to the Far East, and from West to East, at times simultaneously.

  10. Lost circulation technology development status

    Energy Technology Data Exchange (ETDEWEB)

    Glowka, D.A.; Schafer, D.M.; Loeppke, G.E.; Scott, D.D.; Wernig, M.D.; Wright, E.K.

    1992-07-01

    Lost circulation is the loss of drilling fluid from the wellbore to fractures or pores in the rock formation. In geothermal drilling, lost circulation is often a serious problem that contributes greatly to the cost of the average geothermal well. The Lost Circulation Technology Development Program is sponsored at Sandia National Laboratories by the US Department of Energy. The goal of the program is to reduce lost circulation costs by 30--50% through the development of mitigation and characterization technology. This paper describes the technical progress made in this program during the period April 1991--March 1992. 8 refs.

  11. Percutaneous interventions in Fontan circulation

    Directory of Open Access Journals (Sweden)

    Eduardo Franco

    2015-09-01

    Conclusions: Interventional catheterization procedures are often necessary to reach and maintain the fragile Fontan circulation, mainly in patients with right morphology systemic ventricles and fenestrated Fontan conduits.

  12. TROPICAL METEOROLOGY & Climate: Hadley Circulation

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Jian; Vecchi, Gabriel A.

    2015-01-30

    The Hadley circulation, a prominent circulation feature characterized by rising air near the Equator and sinking air in the subtropics, defines the position of dry subtropical areas and is a fundamental regulator of the earth’s energy and momentum budgets. The character of the Hadley circulation, and its related precipitation regimes, exhibits variation and change in response to both climate variability and radiative forcing changes. The strength and position of the Hadley circulation change from year to year paced by El Niño and La Niña events. Over the last few decades of the twentieth century, the Hadley cell has expanded poleward in both hemispheres, with changes in atmospheric composition (including stratospheric ozone depletion and greenhouse gas increases) thought to have contributed to its expansion. This article introduces the basic phenomenology and driving mechanism of the Hadley circulation and discusses its variations under both natural and anthropogenic climate forcings.

  13. Sino-Danish Brain Circulation

    DEFF Research Database (Denmark)

    Bertelsen, Rasmus Gjedssø; Du, Xiangyun; Søndergaard, Morten Karnøe

    2014-01-01

    China is faced with urgent needs to develop an economically and environmentally sustainable economy based on innovation and knowledge. Brain circulation and research and business investments from the outside are central for this development. Sino-American brain circulation and research...... and investment by overseas researchers and entrepreneurs are well described. In that case, the US is the center of global R&D and S&T. However, the brain circulation and research and investments between a small open Scandinavian economy, such as Denmark, and the huge developing economy of China are not well...... understood. In this case, Denmark is very highly developed, but a satellite in the global R&D and S&T system. With time and the growth of China as a R&D and S&T power house, both Denmark and China will benefit from brain circulation between them. Such brain circulation is likely to play a key role in flows...

  14. The circulation physiology of agroecosystems

    Institute of Scientific and Technical Information of China (English)

    Cao Zhiping; Richard Dawson

    2007-01-01

    This paper represents an effort to enlarge the understanding of the biophysical foundation of agroecosystems by using an analogy with the circulation of the blood in the human body. The circulation function in the human body can be represented as arterial pressure. The factors affecting arterial pressure in the human body have direct counterparts in the cultivation-husbandry system. The relationship between circulation pressure and the factors affecting that pressure in the cultivation-husbandry system are similar to the relationship between the arterial pressure and factors affecting arterial pressure in the human body. Furthermore, circulation resistance in the cultivation-husbandry system can be shown to be analogous to the calculation of peripheral resistance in the human body by Poiseuille's formula.

  15. Sequence determinants of breakpoint location during HIV-1 intersubtype recombination.

    Science.gov (United States)

    Baird, Heather A; Galetto, Román; Gao, Yong; Simon-Loriere, Etienne; Abreha, Measho; Archer, John; Fan, Jun; Robertson, David L; Arts, Eric J; Negroni, Matteo

    2006-01-01

    Retroviral recombination results from strand switching, during reverse transcription, between the two copies of genomic RNA present in the virus. We analysed recombination in part of the envelope gene, between HIV-1 subtype A and D strains. After a single infection cycle, breakpoints clustered in regions corresponding to the constant portions of Env. With some exceptions, a similar distribution was observed after multiple infection cycles, and among recombinant sequences in the HIV Sequence Database. We compared the experimental data with computer simulations made using a program that only allows recombination to occur whenever an identical base is present in the aligned parental RNAs. Experimental recombination was more frequent than expected on the basis of simulated recombination when, in a region spanning 40 nt from the 5' border of a breakpoint, no more than two discordant bases between the parental RNAs were present. When these requirements were not fulfilled, breakpoints were distributed randomly along the RNA, closer to the distribution predicted by computer simulation. A significant preference for recombination was also observed for regions containing homopolymeric stretches. These results define, for the first time, local sequence determinants for recombination between divergent HIV-1 isolates.

  16. Sequence determinants of breakpoint location during HIV-1 intersubtype recombination

    Science.gov (United States)

    Baird, Heather A.; Galetto, Román; Gao, Yong; Simon-Loriere, Etienne; Abreha, Measho; Archer, John; Fan, Jun; Robertson, David L.; Arts, Eric J.; Negroni, Matteo

    2006-01-01

    Retroviral recombination results from strand switching, during reverse transcription, between the two copies of genomic RNA present in the virus. We analysed recombination in part of the envelope gene, between HIV-1 subtype A and D strains. After a single infection cycle, breakpoints clustered in regions corresponding to the constant portions of Env. With some exceptions, a similar distribution was observed after multiple infection cycles, and among recombinant sequences in the HIV Sequence Database. We compared the experimental data with computer simulations made using a program that only allows recombination to occur whenever an identical base is present in the aligned parental RNAs. Experimental recombination was more frequent than expected on the basis of simulated recombination when, in a region spanning 40 nt from the 5′ border of a breakpoint, no more than two discordant bases between the parental RNAs were present. When these requirements were not fulfilled, breakpoints were distributed randomly along the RNA, closer to the distribution predicted by computer simulation. A significant preference for recombination was also observed for regions containing homopolymeric stretches. These results define, for the first time, local sequence determinants for recombination between divergent HIV-1 isolates. PMID:17003055

  17. Seasonal overturning circulation in the Red Sea: 2. Winter circulation

    KAUST Repository

    Yao, Fengchao

    2014-04-01

    The shallow winter overturning circulation in the Red Sea is studied using a 50 year high-resolution MITgcm (MIT general circulation model) simulation with realistic atmospheric forcing. The overturning circulation for a typical year, represented by 1980, and the climatological mean are analyzed using model output to delineate the three-dimensional structure and to investigate the underlying dynamical mechanisms. The horizontal model circulation in the winter of 1980 is dominated by energetic eddies. 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 24N. 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. The simulated water exchange is not hydraulically controlled in the Strait of Bab el Mandeb; instead, the exchange is limited by bottom and lateral boundary friction and, to a lesser extent, by interfacial friction due to the vertical viscosity at the interface between the inflow and the outflow. Key Points Sinking occurs in a narrow boundary layer along the eastern boundary Surface western boundary current switches into an eastern boundary current Water exchange in the Strait of Bab el Mandeb is not hydraulically controlled © 2014. American Geophysical Union. All Rights Reserved.

  18. The Invertibility, Explicit Determinants, and Inverses of Circulant and Left Circulant and g-Circulant Matrices Involving Any Continuous Fibonacci and Lucas Numbers

    Directory of Open Access Journals (Sweden)

    Zhaolin Jiang

    2014-01-01

    Full Text Available Circulant matrices play an important role in solving delay differential equations. In this paper, circulant type matrices including the circulant and left circulant and g-circulant matrices with any continuous Fibonacci and Lucas numbers are considered. Firstly, the invertibility of the circulant matrix is discussed and the explicit determinant and the inverse matrices by constructing the transformation matrices are presented. Furthermore, the invertibility of the left circulant and g-circulant matrices is also studied. We obtain the explicit determinants and the inverse matrices of the left circulant and g-circulant matrices by utilizing the relationship between left circulant, g-circulant matrices and circulant matrix, respectively.

  19. 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.

  20. Atmospheric Circulation of Terrestrial Exoplanets

    CERN Document Server

    Showman, Adam P; Merlis, Timothy M; Kaspi, Yohai

    2013-01-01

    The investigation of planets around other stars began with the study of gas giants, but is now extending to the discovery and characterization of super-Earths and terrestrial planets. Motivated by this observational tide, we survey the basic dynamical principles governing the atmospheric circulation of terrestrial exoplanets, and discuss the interaction of their circulation with the hydrological cycle and global-scale climate feedbacks. Terrestrial exoplanets occupy a wide range of physical and dynamical conditions, only a small fraction of which have yet been explored in detail. Our approach is to lay out the fundamental dynamical principles governing the atmospheric circulation on terrestrial planets--broadly defined--and show how they can provide a foundation for understanding the atmospheric behavior of these worlds. We first survey basic atmospheric dynamics, including the role of geostrophy, baroclinic instabilities, and jets in the strongly rotating regime (the "extratropics") and the role of the Hadle...

  1. Circulation in blast driven instabilities

    Science.gov (United States)

    Henry de Frahan, Marc; Johnsen, Eric

    2016-11-01

    Mixing in many natural phenomena (e.g. supernova collapse) and engineering applications (e.g. inertial confinement fusion) is often initiated through hydrodynamic instabilities. Explosions in these systems give rise to blast waves which can interact with perturbations at interfaces between different fluids. Blast waves are formed by a shock followed by a rarefaction. This wave profile leads to complex time histories of interface acceleration. In addition to the instabilities induced by the acceleration field, the rarefaction from the blast wave decompresses the material at the interface, further increasing the perturbation growth. After the passage of the wave, circulation circulation generated by the blast wave through baroclinic vorticity continues to act upon the interface. In this talk, we provide scaling laws for the circulation and amplitude growth induced by the blast wave. Numerical simulations of the multifluid Euler equations solved using a high-order accurate Discontinuous Galerkin method are used to validate the theoretical results.

  2. VanderLaan Circulant Type Matrices

    Directory of Open Access Journals (Sweden)

    Hongyan Pan

    2015-01-01

    Full Text Available Circulant matrices have become a satisfactory tools in control methods for modern complex systems. In the paper, VanderLaan circulant type matrices are presented, which include VanderLaan circulant, left circulant, and g-circulant matrices. The nonsingularity of these special matrices is discussed by the surprising properties of VanderLaan numbers. The exact determinants of VanderLaan circulant type matrices are given by structuring transformation matrices, determinants of well-known tridiagonal matrices, and tridiagonal-like matrices. The explicit inverse matrices of these special matrices are obtained by structuring transformation matrices, inverses of known tridiagonal matrices, and quasi-tridiagonal matrices. Three kinds of norms and lower bound for the spread of VanderLaan circulant and left circulant matrix are given separately. And we gain the spectral norm of VanderLaan g-circulant matrix.

  3. Conservation of Circulation in Magnetohydrodynamics

    CERN Document Server

    Bekenstein, J D; Bekenstein, Jacob D.; Oron, Asaf

    2000-01-01

    We demonstrate, both at the Newtonian and (general) relativistic levels, theexistence of a generalization of Kelvin's circulation theorem (for pure fluids)which is applicable to perfect magnetohydrodynamics. The argument is based onthe least action principle for magnetohydrodynamic flow. Examples of the newconservation law are furnished. The new theorem should be helpful inidentifying new kinds of vortex phenomena distinct from magnetic ropes or fluidvortices.

  4. Optimal Backward Perturbation Analysis for the Block Skew Circulant Linear Systems with Skew Circulant Blocks

    Directory of Open Access Journals (Sweden)

    Zhaolin Jiang

    2014-01-01

    Full Text Available We first give the block style spectral decomposition of arbitrary block skew circulant matrix with skew circulant blocks. Secondly, we obtain the singular value of block skew circulant matrix with skew circulant blocks as well. Finally, based on the block style spectral decomposition, we deal with the optimal backward perturbation analysis for the block skew circulant linear system with skew circulant blocks.

  5. Physiology of the fetal circulation.

    Science.gov (United States)

    Kiserud, Torvid

    2005-12-01

    Our understanding of fetal circulatory physiology is based on experimental animal data, and this continues to be an important source of new insight into developmental mechanisms. A growing number of human studies have investigated the human physiology, with results that are similar but not identical to those from animal studies. It is time to appreciate these differences and base more of our clinical approach on human physiology. Accordingly, the present review focuses on distributional patterns and adaptational mechanisms that were mainly discovered by human studies. These include cardiac output, pulmonary and placental circulation, fetal brain and liver, venous return to the heart, and the fetal shunts (ductus venosus, foramen ovale and ductus arteriosus). Placental compromise induces a set of adaptational and compensational mechanisms reflecting the plasticity of the developing circulation, with both short- and long-term implications. Some of these aspects have become part of the clinical physiology of today with consequences for surveillance and treatment.

  6. Proper Sizing of Circulation Pumps

    DEFF Research Database (Denmark)

    Tommerup, Henrik M.; Nørgaard, Jørgen

    2007-01-01

    , but the results can be applied to Europe in general. Despite the small sample of houses involved in the test, 15 houses, some rather safe conclusions can be drawn from the results, which showed that newly developed pumps with power consumption around 5-8 W, can perform the task of circulating the water......The paper describes the preliminary results from field tests of replacing various types of old pumps used for circulating water in heating systems in single- and double-family houses with new types of pumps. The tests were carried out in Denmark for the Danish Electricity Savings Trust...... sufficiently to keep the houses satisfactorily warm during the heating season of the test. The old replaced pumps used 5-10 times more power. In Europe alone, a gradual replacement of the present vastly oversized pumps with such small but sufficient pumps can save the construction of 17 large power plants...

  7. Journalism as Cultures of Circulation

    DEFF Research Database (Denmark)

    Bødker, Henrik

    2013-01-01

    The universe of journalism has always consisted of interspersed texts, meanings and practices. Yet, much journalism research has often isolated either texts and/or contexts and as such assumed relations between professional practices, informed (rational) readers and (conceived) core texts...... of journalism. It is, however, more important than ever to shift attention away from texts to the processes through which they are circulated. This is partly because the many cultural forms of journalism (textual, institutional, technological, material, behavioural and imagined) are undergoing significant......, likes, comments, searches, journalist roles, writing and reading positions and identities etc. Such forms will be traced within the mediation of a specific event with the overall aim of beginning a theorization of the landscape of journalism as highly interrelated cultures of circulation....

  8. Ocean circulation generated magnetic signals

    DEFF Research Database (Denmark)

    Manoj, C.; Kuvshinov, A.; Maus, S.

    2006-01-01

    Conducting ocean water, as it flows through the Earth's magnetic field, generates secondary electric and magnetic fields. An assessment of the ocean-generated magnetic fields and their detectability may be of importance for geomagnetism and oceanography. Motivated by the clear identification...... of ocean tidal signatures in the CHAMP magnetic field data we estimate the ocean magnetic signals of steady flow using a global 3-D EM numerical solution. The required velocity data are from the ECCO ocean circulation experiment and alternatively from the OCCAM model for higher resolution. We assume...... of the magnetic field, as compared to the ECCO simulation. Besides the expected signatures of the global circulation patterns, we find significant seasonal variability of ocean magnetic signals in the Indian and Western Pacific Oceans. Compared to seasonal variation, interannual variations produce weaker signals....

  9. Conservation of circulation in magnetohydrodynamics

    Science.gov (United States)

    Bekenstein; Oron

    2000-10-01

    We demonstrate at both the Newtonian and (general) relativistic levels the existence of a generalization of Kelvin's circulation theorem (for pure fluids) that is applicable to perfect magnetohydrodynamics. The argument is based on the least action principle for magnetohydrodynamic flow. Examples of the new conservation law are furnished. The new theorem should be helpful in identifying new kinds of vortex phenomena distinct from magnetic ropes or fluid vortices.

  10. Conservation of Circulation in Magnetohydrodynamics

    OpenAIRE

    Bekenstein, Jacob D.; Oron, Asaf

    2000-01-01

    We demonstrate, both at the Newtonian and (general) relativistic levels, the existence of a generalization of Kelvin's circulation theorem (for pure fluids) which is applicable to perfect magnetohydrodynamics. The argument is based on the least action principle for magnetohydrodynamic flow. Examples of the new conservation law are furnished. The new theorem should be helpful in identifying new kinds of vortex phenomena distinct from magnetic ropes or fluid vortices.

  11. Hall Effect Gyrators and Circulators

    Science.gov (United States)

    Viola, Giovanni; DiVincenzo, David P.

    2014-04-01

    The electronic circulator and its close relative the gyrator are invaluable tools for noise management and signal routing in the current generation of low-temperature microwave systems for the implementation of new quantum technologies. The current implementation of these devices using the Faraday effect is satisfactory but requires a bulky structure whose physical dimension is close to the microwave wavelength employed. The Hall effect is an alternative nonreciprocal effect that can also be used to produce desired device functionality. We review earlier efforts to use an Ohmically contacted four-terminal Hall bar, explaining why this approach leads to unacceptably high device loss. We find that capacitive coupling to such a Hall conductor has much greater promise for achieving good circulator and gyrator functionality. We formulate a classical Ohm-Hall analysis for calculating the properties of such a device, and show how this classical theory simplifies remarkably in the limiting case of the Hall angle approaching 90°. In this limit, we find that either a four-terminal or a three-terminal capacitive device can give excellent circulator behavior, with device dimensions far smaller than the ac wavelength. An experiment is proposed to achieve GHz-band gyration in millimeter (and smaller) scale structures employing either semiconductor heterostructure or graphene Hall conductors. An inductively coupled scheme for realizing a Hall gyrator is also analyzed.

  12. Circulating follistatin in relation to energy metabolism

    DEFF Research Database (Denmark)

    Hansen, Jakob Schiøler; Plomgaard, Peter

    2016-01-01

    Recently, substantial evidence has emerged that the liver contributes significantly to the circulating levels of follistatin and that circulating follistatin is tightly regulated by the glucagon-to-insulin ratio. Both observations are based on investigations of healthy subjects. These novel...... a relation to energy metabolism. In this narrative review, we attempt to reconcile the existing findings on circulating follistatin with the novel concept that circulating follistatin is a liver-derived molecule regulated by the glucagon-to-insulin ratio. The picture emerging is that conditions associated...... with elevated levels of circulating follistatin have a metabolic denominator with decreased insulin sensitivity and/or hyperglucagoneimia....

  13. Matrix-free constructions of circulant and block circulant preconditioners

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Chao; Ng, Esmond G.; Penczek, Pawel A.

    2001-12-01

    A framework for constructing circulant and block circulant preconditioners (C) for a symmetric linear system Ax=b arising from certain signal and image processing applications is presented in this paper. The proposed scheme does not make explicit use of matrix elements of A. It is ideal for applications in which A only exists in the form of a matrix vector multiplication routine, and in which the process of extracting matrix elements of A is costly. The proposed algorithm takes advantage of the fact that for many linear systems arising from signal or image processing applications, eigenvectors of A can be well represented by a small number of Fourier modes. Therefore, the construction of C can be carried out in the frequency domain by carefully choosing its eigenvalues so that the condition number of C{sup T} AC can be reduced significantly. We illustrate how to construct the spectrum of C in a way such that the smallest eigenvalues of C{sup T} AC overlaps with those of A extremely well while the largest eigenvalues of C{sup T} AC are smaller than those of A by several orders of magnitude. Numerical examples are provided to demonstrate the effectiveness of the preconditioner on accelerating the solution of linear systems arising from image reconstruction application.

  14. Malheur National Wildlife Refuge: Narrative Report: 1937: Camp Five Mile BF-1: 2: February

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This narrative report from the Civilian Conservation Corps summarizes activities done for Five Mile on Malheur Migratory Waterfowl Refuge. Topics include...

  15. Malheur National Wildlife Refuge: Narrative Report: 1937: Camp Five Mile BF-1: 1: January

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This narrative report from the Civilian Conservation Corps summarizes activities done for Five Mile on Malheur Migratory Waterfowl Refuge. Topics include...

  16. Malheur National Wildlife Refuge: Narrative Report: 1937: Camp Five Mile BF-1: 4: April

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This narrative report from the Civilian Conservation Corps summarizes activities done for Five Mile on Malheur Migratory Waterfowl Refuge. Topics include...

  17. Malheur National Wildlife Refuge: Narrative Report: 1938: Camp Five Mile BF-1: 1: March-April

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This narrative report from the Civilian Conservation Corps summarizes activities done for Five Mile on Malheur Migratory Waterfowl Refuge. Topics include...

  18. Malheur National Wildlife Refuge: Narrative Report: 1937: Camp Five Mile BF-1: 5: May

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This narrative report from the Civilian Conservation Corps summarizes activities done for Five Mile on Malheur Migratory Waterfowl Refuge. Topics include...

  19. Malheur National Wildlife Refuge: Narrative Report: 1936: Camp Five Mile BF-1: 3: December

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This narrative report from the Civilian Conservation Corps summarizes activities done for Five Mile on Malheur Migratory Waterfowl Refuge. Topics include...

  20. Malheur National Wildlife Refuge: Narrative Report: 1937: Camp Five Mile BF-1: 6: June

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This narrative report from the Civilian Conservation Corps summarizes activities done for Five Mile on Malheur Migratory Waterfowl Refuge. Topics include...

  1. Malheur National Wildlife Refuge: Narrative Report: 1936: Camp Five Mile BF-1: 2: November

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This narrative report from the Civilian Conservation Corps summarizes activities done for Five Mile on Malheur Migratory Waterfowl Refuge. Topics include...

  2. Malheur National Wildlife Refuge: Narrative Report: 1936: Camp Five Mile BF-1: 1: October

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This narrative report from the Civilian Conservation Corps summarizes activities done for Five Mile on Malheur Migratory Waterfowl Refuge. Topics include...

  3. Autonomic Regulation of Splanchnic Circulation

    Directory of Open Access Journals (Sweden)

    Kathleen A Fraser

    1991-01-01

    Full Text Available The role of the autonomic nervous system in circulatory regulation of the splanchnic organs (stomach, small intestine, colon, liver, pancreas and spleen is reviewed. In general, the sympathetic nervous system is primarily involved in vasoconstriction, while the parasympathetic contributes to vasodilation. Vasoconstriction in the splanchnic circulation appears to be mediated by alpha-2 receptors and vasodilation by activation of primary afferent nerves with subsequent release of vasodilatory peptides, or by stimulation of beta-adrenergic receptors. As well, an important function of the autonomic nervous system is to provide a mechanism by which splanchnic vascular reserve can be mobilized during stress to maintain overall cardiovascular homeostasis.

  4. Intestinal circulation during inhalation anesthesia

    Energy Technology Data Exchange (ETDEWEB)

    Tverskoy, M.; Gelman, S.; Fowler, K.C.; Bradley, E.L.

    1985-04-01

    This study was designed to evaluate the influence of inhalational agents on the intestinal circulation in an isolated loop preparation. Sixty dogs were studied, using three intestinal segments from each dog. Selected intestinal segments were pumped with aortic blood at a constant pressure of 100 mmHg. A mixture of /sub 86/Rb and 9-microns spheres labeled with /sup 141/Ce was injected into the arterial cannula supplying the intestinal loop, while mesenteric venous blood was collected for activity counting. A very strong and significant correlation was found between rubidium clearance and microsphere entrapment (r = 0.97, P less than 0.0001). Nitrous oxide anesthesia was accompanied by a higher vascular resistance (VR), lower flow (F), rubidium clearance (Cl-Rb), and microspheres entrapment (Cl-Sph) than pentobarbital anesthesia, indicating that the vascular bed in the intestinal segment was constricted and flow (total and nutritive) decreased. Halothane, enflurane, and isoflurane anesthesia were accompanied by a much lower arteriovenous oxygen content difference (AVDO/sub 2/) and oxygen uptake than pentobarbital or nitrous oxide. Compared with pentobarbital, enflurane anesthesia was not accompanied by marked differences in VR, F, Cl-Rb, and Cl-Sph; halothane at 2 MAC decreased VR and increased F and Cl-Rb while isoflurane increased VR and decreased F. alpha-Adrenoceptor blockade with phentolamine (1 mg . kg-1) abolished isoflurane-induced vasoconstriction, suggesting that the increase in VR was mediated via circulating catecholamines.

  5. 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.

  6. Linear thermal circulator based on Coriolis forces.

    Science.gov (United States)

    Li, Huanan; Kottos, Tsampikos

    2015-02-01

    We show that the presence of a Coriolis force in a rotating linear lattice imposes a nonreciprocal propagation of the phononic heat carriers. Using this effect we propose the concept of Coriolis linear thermal circulator which can control the circulation of a heat current. A simple model of three coupled harmonic masses on a rotating platform permits us to demonstrate giant circulating rectification effects for moderate values of the angular velocities of the platform.

  7. A brief etymology of the collateral circulation.

    Science.gov (United States)

    Faber, James E; Chilian, William M; Deindl, Elisabeth; van Royen, Niels; Simons, Michael

    2014-09-01

    It is well known that the protective capacity of the collateral circulation falls short in many individuals with ischemic disease of the heart, brain, and lower extremities. In the past 15 years, opportunities created by molecular and genetic tools, together with disappointing outcomes in many angiogenic trials, have led to a significant increase in the number of studies that focus on: understanding the basic biology of the collateral circulation; identifying the mechanisms that limit the collateral circulation's capacity in many individuals; devising methods to measure collateral extent, which has been found to vary widely among individuals; and developing treatments to increase collateral blood flow in obstructive disease. Unfortunately, accompanying this increase in reports has been a proliferation of vague terms used to describe the disposition and behavior of this unique circulation, as well as the increasing misuse of well-ensconced ones by new (and old) students of collateral circulation. With this in mind, we provide a brief glossary of readily understandable terms to denote the formation, adaptive growth, and maladaptive rarefaction of collateral circulation. We also propose terminology for several newly discovered processes that occur in the collateral circulation. Finally, we include terms used to describe vessels that are sometimes confused with collaterals, as well as terms describing processes active in the general arterial-venous circulation when ischemic conditions engage the collateral circulation. We hope this brief review will help unify the terminology used in collateral research.

  8. Role of Circulating Fibrocytes in Cardiac Fibrosis

    Institute of Scientific and Technical Information of China (English)

    Rong-Jie Lin; Zi-Zhuo Su; Shu-Min Liang; Yu-Yang Chen; Xiao-Rong Shu; Ru-Qiong Nie; Jing-Feng Wang

    2016-01-01

    Objective: It is revealed that circulating fibrocytes are elevated in patients/animals with cardiac fibrosis, and this review aims to provide an introduction to circulating fibrocytes and their role in cardiac fibrosis.Data Sources: This review is based on the data from 1994 to present obtained from PubMed.The search terms were "circulating fibrocytes" and "cardiac fibrosis".Study Selection: Articles and critical reviews, which are related to circulating fibrocytes and cardiac fibrosis, were selected.Results: Circulating fibrocytes, which are derived from hematopoietic stem cells, represent a subset of peripheral blood mononuclear cells exhibiting mixed morphological and molecular characteristics ofhematopoietic and mesenchymal cells (CD34+/CD45+/collagen I+).They can produce extracellular matrix and many cytokines.It is shown that circulating fibrocytes participate in many fibrotic diseases, including cardiac fibrosis.Evidence accumulated in recent years shows that aging individuals and patients with hypertension, heart failure, coronary heart disease, and atrial fibrillation have more circulating fibrocytes in peripheral blood and/or heart tissue, and this elevation of circulating fibrocytes is correlated with the degree of fibrosis in the hearts.Conclusions: Circulating fibrocytes are effector cells in cardiac fibrosis.

  9. The Rank of Integral Circulant Graphs

    Institute of Scientific and Technical Information of China (English)

    ZHOU Hou-qing

    2014-01-01

    A graph is called an integral graph if it has an integral spectrum i.e., all eigen-values are integers. A graph is called circulant graph if it is Cayley graph on the circulant group, i.e., its adjacency matrix is circulant. The rank of a graph is defined to be the rank of its adjacency matrix. This importance of the rank, due to applications in physics, chemistry and combinatorics. In this paper, using Ramanujan sums, we study the rank of integral circulant graphs and gave some simple computational formulas for the rank and provide an example which shows the formula is sharp.

  10. Role of Circulating Fibrocytes in Cardiac Fibrosis

    Science.gov (United States)

    Lin, Rong-Jie; Su, Zi-Zhuo; Liang, Shu-Min; Chen, Yu-Yang; Shu, Xiao-Rong; Nie, Ru-Qiong; Wang, Jing-Feng; Xie, Shuang-Lun

    2016-01-01

    Objective: It is revealed that circulating fibrocytes are elevated in patients/animals with cardiac fibrosis, and this review aims to provide an introduction to circulating fibrocytes and their role in cardiac fibrosis. Data Sources: This review is based on the data from 1994 to present obtained from PubMed. The search terms were “circulating fibrocytes” and “cardiac fibrosis”. Study Selection: Articles and critical reviews, which are related to circulating fibrocytes and cardiac fibrosis, were selected. Results: Circulating fibrocytes, which are derived from hematopoietic stem cells, represent a subset of peripheral blood mononuclear cells exhibiting mixed morphological and molecular characteristics of hematopoietic and mesenchymal cells (CD34+/CD45+/collagen I+). They can produce extracellular matrix and many cytokines. It is shown that circulating fibrocytes participate in many fibrotic diseases, including cardiac fibrosis. Evidence accumulated in recent years shows that aging individuals and patients with hypertension, heart failure, coronary heart disease, and atrial fibrillation have more circulating fibrocytes in peripheral blood and/or heart tissue, and this elevation of circulating fibrocytes is correlated with the degree of fibrosis in the hearts. Conclusions: Circulating fibrocytes are effector cells in cardiac fibrosis. PMID:26831236

  11. Inflammatory response and extracorporeal circulation.

    Science.gov (United States)

    Kraft, Florian; Schmidt, Christoph; Van Aken, Hugo; Zarbock, Alexander

    2015-06-01

    Patients undergoing cardiac surgery with extracorporeal circulation (EC) frequently develop a systemic inflammatory response syndrome. Surgical trauma, ischaemia-reperfusion injury, endotoxaemia and blood contact to nonendothelial circuit compounds promote the activation of coagulation pathways, complement factors and a cellular immune response. This review discusses the multiple pathways leading to endothelial cell activation, neutrophil recruitment and production of reactive oxygen species and nitric oxide. All these factors may induce cellular damage and subsequent organ injury. Multiple organ dysfunction after cardiac surgery with EC is associated with an increased morbidity and mortality. In addition to the pathogenesis of organ dysfunction after EC, this review deals with different therapeutic interventions aiming to alleviate the inflammatory response and consequently multiple organ dysfunction after cardiac surgery.

  12. PRELIMINARY STUDY ON CIRCULATION HEIGHT OF CIRCULATION FLOW WITH THE HORIZONTAL AXIS

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    In this paper, the relationship between circulation heights of circulation flow with horizontal axis and incident flow conditions as well as side slope angles of trenches was systematically analyzed on the basis of the velocity distribution data observed in a series of model tests in a flume, and the related formula for the circulation height was proposed. Moreover, the variation of circulation flow intensity was also analyzed.

  13. Dispensing with the DVD Circulation Dilemma

    Science.gov (United States)

    Ellis, Mark

    2008-01-01

    Richmond Public Library (RPL) is a four-branch suburban library with the highest per capita circulation of any comparable library in Canada. While DVDs naturally fit into RPL's emphasis on popular material, circulating them using the standard model proved problematic: Long hold queues built up, DVDs idled on the hold shelves, and the circulation…

  14. Space-Time radar waveforms: circulating codes

    NARCIS (Netherlands)

    Babur, G.; Aubry, P.; Le Chevalier, F.

    2013-01-01

    This paper describes a concept of the circulating codes covering the whole class of the space-time codes. The circulating codes do not narrow the radiated pattern of the antenna array, thus providing a wide angular coverage, possibly tunable. In turn, the beam-forming on transmit is achievable by me

  15. On So's conjecture for integral circulant graphs

    Directory of Open Access Journals (Sweden)

    J.W. Sander

    2015-04-01

    According to a conjecture of {\\sc So} two integral circulant graphs are isomorphic if and only if they are isospectral, i.e. they have the same eigenvalues (counted with multiplicities. We prove a weaker form of this conjecture, namely, that two integral circulant graphs with multiplicative divisor sets are isomorphic if and only if their spectral vectors coincide.

  16. Physiology of the fetal and transitional circulation.

    Science.gov (United States)

    Finnemore, Anna; Groves, Alan

    2015-08-01

    The fetal circulation is an entirely transient event, not replicated at any point in later life, and functionally distinct from the pediatric and adult circulations. Understanding of the physiology of the fetal circulation is vital for accurate interpretation of hemodynamic assessments in utero, but also for management of circulatory compromise in premature infants, who begin extrauterine life before the fetal circulation has finished its maturation. This review summarizes the key classical components of circulatory physiology, as well as some of the newer concepts of physiology that have been appreciated in recent years. The immature circulation has significantly altered function in all aspects of circulatory physiology. The mechanisms and significance of these differences are also discussed, as is the impact of these alterations on the circulatory transition of infants born prematurely.

  17. Interannual variability of the Adriatic Sea circulation

    Science.gov (United States)

    Beg Paklar, Gordana; Sepic, Jadranka; Grbec, Branka; Dzoic, Tomislav; Kovac, Zarko; Ivatek-Sahdan, Stjepan

    2016-04-01

    The Regional Ocean Modeling System (ROMS) was implemented in order to reproduce interannual variability of the Adriatic Sea circulation. Simulations and model result analysis were performed for a three-year period from 1st January 2011 to 31st December 2013. ROMS model run was forced with realistic atmospheric fields obtained from meteorological model Aladin, climatological river discharges, tides and Mediterranean circulation imposed at the southern open boundary. Atmospheric forcing included momentum, heat and water fluxes calculated interactively from the Aladin surface fields during ROMS model simulations. Model results were compared with available CTD and ADCP measurements and discussed in the light of the climatological circulation and thermohaline properties of the Adriatic Sea and its coastal areas. Interannual variability in the Adriatic circulation is related to the prevailing atmospheric conditions, changes in the hydrological conditions and water mass exchange at the Otranto Strait. Basic features of the Adriatic circulation - basin-wide cyclonic circulation with several embedded smaller cyclonic gyres around main pits - are well reproduced by ROMS model. Modelled temperatures and salinities are within corresponding seasonal intervals, although measured profiles generally indicate stronger stratification than modelled ones. Summer circulation in 2011 with current reversal obtained along the eastern Adriatic coast was related to the sampling results of the early fish stages as well as to ARGO drifter movements. Simulated fields from the Adriatic scale model were used to prescribe the initial and open boundary conditions for the interannual simulation in the middle Adriatic coastal domain.

  18. SpaceX Dragon Air Circulation System

    Science.gov (United States)

    Hernandez, Brenda; Piatrovich, Siarhei; Prina, Mauro

    2011-01-01

    The Dragon capsule is a reusable vehicle being developed by Space Exploration Technologies (SpaceX) that will provide commercial cargo transportation to the International Space Station (ISS). Dragon is designed to be a habitable module while it is berthed to ISS. As such, the Dragon Environmental Control System (ECS) consists of pressure control and pressure equalization, air sampling, fire detection, illumination, and an air circulation system. The air circulation system prevents pockets of stagnant air in Dragon that can be hazardous to the ISS crew. In addition, through the inter-module duct, the air circulation system provides fresh air from ISS into Dragon. To utilize the maximum volume of Dragon for cargo packaging, the Dragon ECS air circulation system is designed around cargo rack optimization. At the same time, the air circulation system is designed to meet the National Aeronautics Space Administration (NASA) inter-module and intra-module ventilation requirements and acoustic requirements. A flight like configuration of the Dragon capsule including the air circulation system was recently assembled for testing to assess the design for inter-module and intra-module ventilation and acoustics. The testing included the Dragon capsule, and flight configuration in the pressure section with cargo racks, lockers, all of the air circulation components, and acoustic treatment. The air circulation test was also used to verify the Computational Fluid Dynamics (CFD) model of the Dragon capsule. The CFD model included the same Dragon internal geometry that was assembled for the test. This paper will describe the Dragon air circulation system design which has been verified by testing the system and with CFD analysis.

  19. Circulating miRNA and cancer diagnosis

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    miRNAs are a class of small RNA molecules with regulatory function, and play an important role in tumor development and progression. It has been demonstrated that tumor-derived miRNAs exist in the circulating nucleic acids of cancer patients. This phenomenon implies that detection of the circulating miRNA may be an effective method for non-invasive diagnosis of cancer. In this review, we summarize the applications of the circulating miRNA as biomarkers in cancer diagnosis, as well as the latest research progress in this area.

  20. 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...

  1. Head positioning for anterior circulation aneurysms microsurgery

    Directory of Open Access Journals (Sweden)

    Feres Chaddad-Neto

    2014-11-01

    Full Text Available Objective To study the ideal patient's head positioning for the anterior circulation aneurysms microsurgery. Method We divided the study in two parts. Firstly, 10 fresh cadaveric heads were positioned and dissected in order to ideally expose the anterior circulation aneurysm sites. Afterwards, 110 patients were submitted to anterior circulation aneurysms microsurgery. During the surgery, the patient's head was positioned accordingly to the aneurysm location and the results from the cadaveric study. The effectiveness of the position was noted. Results We could determine mainly two patterns for head positioning for the anterior circulation aneurysms. Conclusion The best surgical exposure is related to specific head positions. The proper angle of microscopic view may minimize neurovascular injury and brain retraction.

  2. Deep Circulation in the South China Sea

    Science.gov (United States)

    Zhao, Xiaolong; Zhao, Wei; Xu, Xiaobiao; Tian, Jiwei; Zhou, Chun

    2016-04-01

    The South China Sea (SCS) is the largest marginal sea of the northwest Pacific. The deep circulation in the SCS is investigated on the basis of the Hybrid Coordinate Ocean Model (HYCOM). All the experiments show reasonable agreement with observation from mooring arrays. Analysis of these results provides a detailed spatial structure and temporal variability of the deep circulation in the SCS. The major features of the SCS deep circulation are basin-scale cyclonic gyre and concentrated deep western boundary current (DWBC). The transport of the DWBC is ~2 Sv at 16.5°N with a width of ~53 km. As flowing southwestward, the DWBC becomes weaker with a wider range. Deep upwelling in the SCS is estimated of 0.19 to 1.15 m d-1 with the strongest area around the DWBC. The model results reveal the existence of 80 to 120 days oscillation in the deep northeastern circulation and the DWBC, which are also the areas with large eddy kinetic energy. This seasonal oscillation is northwestward with a velocity amplitude of ~1.0~1.5 cm s-1. The distribution of mixing parameters in the deep SCS plays a role in both spatial structure and volume transport of the deep circulation. Compared with the north shelf of the SCS with the Luzon Strait, deep circulation in the SCS is more sensitive to the large vertical mixing parameters of the Zhongsha Island Chain area.

  3. Surgical myocardial revascularization without extracorporeal circulation

    Directory of Open Access Journals (Sweden)

    Salomón Soriano Ordinola Rojas

    2003-05-01

    Full Text Available OBJECTIVE: To assess the immediate postoperative period of patients undergoing myocardial revascularization without extracorporeal circulation with different types of grafts. METHODS: One hundred and twelve patients, 89 (79.5% of whom were males, were revascularized without extracorporeal circulation. Their ages ranged from 39 to 85 years. The criteria for indicating myocardial revascularization without extracorporeal circulation were as follows: revascularized coronary artery caliber > 1.5 mm, lack of intramyocardial trajectory on coronary angiography, noncalcified coronary arteries, and tolerance of the heart to the different rotation maneuvers. RESULTS: Myocardial revascularization without extracorporeal circulation was performed in 112 patients. Three were converted to extracorporeal circulation, which required a longer hospital stay but did not impact mortality. During the procedure, the following events were observed: atrial fibrillation in 10 patients, ventricular fibrillation in 4, total transient atrioventricular block in 2, ventricular extrasystoles in 58, use of a device to retrieve red blood cells in 53, blood transfusion in 8, and arterial hypotension in 89 patients. Coronary angiography was performed in 20 patients on the seventh postoperative day when the grafts were patent. CONCLUSION: Myocardial revascularization without extracorporeal circulation is a reproducible technique that is an alternative for treating ischemic heart disease.

  4. 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.

  5. 46 CFR 56.50-45 - Circulating pumps.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 2 2010-10-01 2010-10-01 false Circulating pumps. 56.50-45 Section 56.50-45 Shipping... APPURTENANCES Design Requirements Pertaining to Specific Systems § 56.50-45 Circulating pumps. (a) A main circulating pump and emergency means for circulating water through the main condenser shall be provided....

  6. 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.)

  7. Circulating Endothelial Microparticles in Diabetes Mellitus

    Directory of Open Access Journals (Sweden)

    A. F. Tramontano

    2010-01-01

    Full Text Available Background. Endothelial Microparticles (EMPs are small vesicles shed from activated or apoptotic endothelial cells and involved in cellular cross-talk. Whether EMP immunophenotypes vary according to stimulus in Diabetes Mellitus (DM is not known. We studied the cellular adhesion molecule (CAM profile of circulating EMPs in patients with and without Diabetes Mellitus type 2, who were undergoing elective cardiac catheterization. Methods and Results. EMPs were analyzed by flow cytometry. The absolute median number of EMPs (EMPs/L specific for CD31, CD105, and CD106 was significantly increased in the DM population. The ratio of CD62E/CD31 EMP populations reflected an apoptotic process. Conclusion. Circulating CD31+, CD105+, and CD106+ EMPs were significantly elevated in patients with DM. EMPs were the only independent predictors of DM in our study cohort. In addition, the EMP immunophenotype reflected an apoptotic process. Circulating EMPs may provide new options for risk assessment.

  8. Walker circulation in a transient climate

    Science.gov (United States)

    Plesca, Elina; Grützun, Verena; Buehler, Stefan A.

    2016-04-01

    The tropical overturning circulations modulate the heat exchange across the tropics and between the tropics and the poles. The anthropogenic influence on the climate system will affect these circulations, impacting the dynamics of the Earth system. In this work we focus on the Walker circulation. We investigate its temporal and spatial dynamical changes and their link to other climate features, such as surface and sea-surface temperature patterns, El-Niño Southern Oscillation (ENSO), and ocean heat-uptake, both at global and regional scale. In order to determine the impact of anthropogenic climate change on the tropical circulation, we analyze the outputs of 28 general circulation models (GCMs) from the CMIP5 project. We use the experiment with 1% year-1 increase in CO2 concentration from pre-industrial levels to quadrupling of the concentration. Consistent with previous studies (ex. Ma and Xie 2013), we find that for this experiment most GCMs associate a weakening Walker circulation to a warming transient climate. Due to the role of the Walker Pacific cell in the meridional heat and moisture transport across the tropical Pacific and also the connection to ENSO, we find that a weakened Walker circulation correlates with more extreme El-Niño events, although without a change in their frequency. The spatial analysis of the Pacific Walker cell suggests an eastward displacement of the ascending branch, which is consistent with positive SST anomalies over the tropical Pacific and the link of the Pacific Walker cell to ENSO. Recent studies (ex. England et al. 2014) have linked a strengthened Walker circulation to stronger ocean heat uptake, especially in the western Pacific. The inter-model comparison of the correlation between Walker circulation intensity and ocean heat uptake does not convey a robust response for the investigated experiment. However, there is some evidence that a stronger weakening of the Walker circulation is linked to a higher transient climate

  9. A 12 GHz broadband latching circulator

    Science.gov (United States)

    Katoh, Y.; Konishi, H.; Sakamoto, K.

    The two kinds of latching circulators, external return path and internal return path, are defined, noting the advantages (faster switching speed, lower switching energy, less complicated fabrication) offered by the internal configuration. It is noted, however, that this kind of circulator is difficult to make broadband because the return paths do not seem to act as part of the ferrite junction. The development of a 12-GHz broadband, internal return path circulator with impedance matching transformer and in-phase adjustment screws designed using eigenvalue measurement is described. In describing the operating characteristics, it is noted that more than 25 dB isolation over 11 GHz to 13.5 GHz and 0.25 dB insertion loss is obtained.

  10. Experimental study of natural circulation circuit

    Energy Technology Data Exchange (ETDEWEB)

    Lemos, Wanderley F.; Su, Jian, E-mail: wlemos@lasme.coppe.ufrj.br, E-mail: sujian@lasme.coppe.ufrj.br [Coordenacao dos Programas de Pos-Graduacao de Engenharia (LASME/COPPE/UFRJ), Rio de Janeiro, RJ (Brazil). Lab. de Simulacao e Metodos Numericos; Faccini, Jose L.H., E-mail: faccini@ien.gov.br [Instituto de Engenharia Nuclear (LTE/IEN/CNEN-RJ), Rio de Janeiro, RJ (Brazil). Lab. de Termo-Hidraulica Experimental

    2011-07-01

    This work presents an experimental study about fluid flows behavior in natural circulation, under conditions of single-phase flow. The experiment was performed through experimental thermal-hydraulic circuit built at IEN. This test equipment has performance similar to passive system of residual heat removal present in Advanced Pressurized Water Reactors (APWR). This experimental study aims to observing and analyzing the natural circulation phenomenon, using this experimental circuit that was dimensioned and built based on concepts of similarity and scale. This philosophy allows the analysis of natural circulation behavior in single-phase flow conditions proportionally to the functioning real conditions of a nuclear reactor. The experiment was performed through procedures to initialization of hydraulic feeding of primary and secondary circuits and electrical energizing of resistors installed inside heater. Power controller has availability to adjust values of electrical power to feeding resistors, in order to portray several conditions of energy decay of nuclear reactor in a steady state. Data acquisition system allows the measurement and monitoring of the evolution of the temperature in various points through thermocouples installed in strategic points along hydraulic circuit. The behavior of the natural circulation phenomenon was monitored by graphical interface on computer screen, showing the temperature evolutions of measuring points and results stored in digital spreadsheets. The results stored in digital spreadsheets allowed the getting of data to graphic construction and discussion about natural circulation phenomenon. Finally, the calculus of Reynolds number allowed the establishment for a correlation of friction in function of geometric scales of length, heights and cross section of tubing, considering a natural circulation flow throughout in the region of hot leg. (author)

  11. The stripline circulator theory and practice

    CERN Document Server

    Helszajn, J

    2008-01-01

    Stripline circulator theory and applications from the world's foremost authority. The stripline junction circulator is a unique three-port non-reciprocal microwave junction used to connect a single antenna to both a transmitter and a receiver. Its operation relies on the interaction between an electron spin in a suitably magnetized insulator with an alternating radio frequency magnetic field. In its simplest form, it consists of a microwave planar gyromagnetic resonator symmetrically coupled by three transmission lines. This book explores the magnetic interaction involved in the stripline circ.

  12. Quenching phenomena in natural circulation loop

    Energy Technology Data Exchange (ETDEWEB)

    Umekawa, Hisashi; Ozawa, Mamoru [Kansai Univ., Osaka (Japan); Ishida, Naoki [Daihatsu Motor Company, Osaka (Japan)

    1995-09-01

    Quenching phenomena has been investigated experimentally using circulation loop of liquid nitrogen. During the quenching under natural circulation, the heat transfer mode changes from film boiling to nucleate boiling, and at the same time flux changes with time depending on the vapor generation rate and related two-phase flow characteristics. Moreover, density wave oscillations occur under a certain operating condition, which is closely related to the dynamic behavior of the cooling curve. The experimental results indicates that the occurrence of the density wave oscillation induces the deterioration of effective cooling of the heat surface in the film and the transition boiling regions, which results in the decrease in the quenching velocity.

  13. First circulating beam in the AA

    CERN Multimedia

    1980-01-01

    On 3 July 1980, two years after project authorization, beam circulated for the first time in the AA. It was a 3.56 GeV/c proton test beam. We see an expecting crowd, minutes before the happy event. The persons are too numerous to name them all, but the 3 most prominent ones are at the centre (left to right): Roy Billinge (Joint AA Project Leader, with his hand on the control box), Eifionydd Jones (white shirt), Simon van der Meer (spiritus rector and Joint AA Project Leader). The first antiprotons were injected, made to circulate and cooled soon after, on 14 July 1980.

  14. Influence of external circulation on sludge characteristics during start-up of internal circulation reactor

    Institute of Scientific and Technical Information of China (English)

    DING Jian-nan; WANG Dian-zuo

    2005-01-01

    The start-up of external circulation-added internal circulation(IC) reactor was finished in 26 d, 32 d fewer than that of IC reactor. To evaluate the influence of the added external circulation on the development of granular sludge, the characteristics of the granular sludge taken from the two tested laboratory-scale reactors during start-up were studied. The results show that the added external circulation can enhance biomass granulation, accelerate granule development and improve sludge characteristics. At the end of start-up, the granular size of sludge in external circulation-added IC reactor greatly increases with a size distribution much better than that of sludge in IC reactor. The granular sludge originated from external circulation-added IC reactor contains more extracellular polymers and has a greater settling velocity than that from IC reactor. Methanogenic activity of the granular sludge from the external circulation-added IC reactor started 26 d ago reaches 358.23 mL·g-1·d-1, 1.66 and 1.20 times as great as that of the sludge from the IC reactor started 26 d and 58 d ago respectively.

  15. Unsteady flow about a circulation control airfoil

    Institute of Scientific and Technical Information of China (English)

    刘晶昌; 孙茂; 吴礼义

    1996-01-01

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

  16. IHI-FW circulating fluidized bed boiler

    Energy Technology Data Exchange (ETDEWEB)

    Watanabe, S.; Omata, K.; Ishimoto, R.; Asai, M. (Ishikawajima-Harima Heavy Industries, Co. Ltd., Tokyo (Japan))

    1993-07-01

    The technology and application of the circulating fluidized bed boiler (IHI-FW) are outlined. Circulating fluidized bed boilers have various features as compared with bubbling fluidized bed boilers as follows; a high combustion efficiency, efficient use of limestone for desulfurization, low NOx emission, adaptability to various fuels and capability to cope with load change. The IHI-FW boiler is furthermore featured by water-wall furnace of all-welded structure, water-cooled/steam cooled cyclone, and simple circulating system. The 30 t/h circulating fluidized bed boiler was introduced into the Tsu Works, Omikenshi Co., Ltd., Japan for private power generation. The boiler equipped with a backup heavy oil burner mainly uses semi-anthracite coal, and besides sulfur capture and NOx reduction functions of a bed, a bag filter with a high dust collecting efficiency is installed in an exhaust gas system. The installation period was reduced to 2.5 months, a half of conventional ones, by more assembly in a factory followed by less field works. 7 figs., 2 tabs.

  17. Redefining circulating tumor cells by image processing

    NARCIS (Netherlands)

    Ligthart, S.T.

    2012-01-01

    Circulating tumor cells (CTC) in the blood of patients with metastatic carcinomas are associated with poor survival and can be used to guide therapy. However, CTC are very heterogeneous in size and shape, and are present at very low frequencies. Missing or misjudging a few events may have great cons

  18. Frobenius circulant graphs of valency six

    CERN Document Server

    Thomson, Alison

    2012-01-01

    A Frobenius group is a permutation group which is transitive but not regular such that only the identity element can fix two points. It is well known that such a group is a semidirect product $G = K \\rtimes H$, where $K$ is a nilpotent normal subgroup. A first kind $G$-Frobenius graph is a Cayley graph on $K$ whose connection set is an $H$-orbit $a^H$ for some $a \\in K$ with $ = K$, where $H$ is of even order or $a$ is an involution. Such graphs admit 'perfect' routing and gossiping schemes in some sense. Because of this and the importance of circulant graphs in network design, it is desirable to classify first kind Frobenius circulant graphs. In this paper we classify all 6-valent first kind Frobenius circulant graphs. We give optimal gossiping, routing and broadcasting schemes for such graphs and compute their forwarding indices, Wiener indices and minimum gossip time. We also prove that the broadcasting time of any 6-valent first kind Frobenius circulant is equal to its diameter plus two or three, indicati...

  19. Detecting holocene changes in thermohaline circulation.

    Science.gov (United States)

    Keigwin, L D; Boyle, E A

    2000-02-15

    Throughout the last glacial cycle, reorganizations of deep ocean water masses were coincident with rapid millennial-scale changes in climate. Climate changes have been less severe during the present interglacial, but evidence for concurrent deep ocean circulation change is ambiguous.

  20. Detecting Holocene changes in thermohaline circulation

    OpenAIRE

    Keigwin, L. D.; Boyle, E.A.

    2000-01-01

    Throughout the last glacial cycle, reorganizations of deep ocean water masses were coincident with rapid millennial-scale changes in climate. Climate changes have been less severe during the present interglacial, but evidence for concurrent deep ocean circulation change is ambiguous.

  1. [Circulating "tumor markers" in gastrointestinal tumors].

    Science.gov (United States)

    Borlinghaus, P; Lamerz, R

    1991-09-01

    Tumor markers (TM) of the neoplastic cell can be divided into non-shedded substances and antigens shedded in blood, urine or other body fluids. For clinicians circulating TM are more important. All relevant circulating TM are not useful in screening of asymptomatic patients because of insufficient sensitivity and specificity. With caution they are useful in the observation of risk groups. Circulating TM have their main significance as additional parameters in monitoring symptomatic patients with malignancies. Several follow up determinations are more important than one single measurement. During follow up of tumor patients TM should not be checked automatically if there are no diagnostic or therapeutical consequences. The clinically most important circulating TM in non-hormone secreting tumors of the gastrointestinal tract are the oncofetal antigens CEA and AFP and antigens defined by monoclonal antibodies e. g. CA 19-9 and CA 72-4. AFP is the primary TM in hepatocellular carcinoma, often elevated in hepatoblastoma and always normal in cholangiocellular carcinoma. CEA is the TM of first choice in patients with colorectal carcinomas and liver metastasis. CA 19-9 is TM of first choice in pancreatic carcinoma and additionally of diagnostic value in cholangiocellular carcinoma and tumors of the bile ducts. In cancer of the stomach CA 19-9 and CEA are secondary TM in combination with CA 72-4 as primary TM. Care should be taken that slight and moderate elevations of TM can be observed in benign diseases of liver, pancreas and bowel.

  2. Development Strategies for Rural Key Circulation Service Network

    Institute of Scientific and Technical Information of China (English)

    2012-01-01

    The rural key circulation service network is an important channel for ensuring agricultural products’entry to market and urban industrial products’entry to rural areas.Through in-depth survey and research,we took a look at development changes and current situations of three circulation service networks,namely,circulation of nondurable consumer goods,circulation of agricultural means of production,and circulation of agricultural products.Based on several key problems in rural circulation service network,such as logistics problem,delivery problem,backward transaction mode,and the last kilometer information,we put forward corresponding development countermeasures.

  3. 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...

  4. 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

  5. Silent Circulation of Ross River Virus in French Polynesia

    Directory of Open Access Journals (Sweden)

    Maite Aubry

    2015-08-01

    Discussion: Our results support the existence of autochthonous RRV transmission and suggest that this pathogen has silently circulated in French Polynesia. These findings raise the question of possible undetected circulation of RRV in other Pacific Island Countries and Territories.

  6. Genetically Encoded Voltage Indicators in Circulation Research.

    Science.gov (United States)

    Kaestner, Lars; Tian, Qinghai; Kaiser, Elisabeth; Xian, Wenying; Müller, Andreas; Oberhofer, Martin; Ruppenthal, Sandra; Sinnecker, Daniel; Tsutsui, Hidekazu; Miyawaki, Atsushi; Moretti, Alessandra; Lipp, Peter

    2015-09-08

    Membrane potentials display the cellular status of non-excitable cells and mediate communication between excitable cells via action potentials. The use of genetically encoded biosensors employing fluorescent proteins allows a non-invasive biocompatible way to read out the membrane potential in cardiac myocytes and other cells of the circulation system. Although the approaches to design such biosensors date back to the time when the first fluorescent-protein based Förster Resonance Energy Transfer (FRET) sensors were constructed, it took 15 years before reliable sensors became readily available. Here, we review different developments of genetically encoded membrane potential sensors. Furthermore, it is shown how such sensors can be used in pharmacological screening applications as well as in circulation related basic biomedical research. Potentials and limitations will be discussed and perspectives of possible future developments will be provided.

  7. On-Chip Microwave Quantum Hall Circulator

    Science.gov (United States)

    Mahoney, A. C.; Colless, J. I.; Pauka, S. J.; Hornibrook, J. M.; Watson, J. D.; Gardner, G. C.; Manfra, M. J.; Doherty, A. C.; Reilly, D. J.

    2017-01-01

    Circulators are nonreciprocal circuit elements that are integral to technologies including radar systems, microwave communication transceivers, and the readout of quantum information devices. Their nonreciprocity arises from the interference of microwaves over the centimeter scale of the signal wavelength, in the presence of bulky magnetic media that breaks time-reversal symmetry. Here, we realize a completely passive on-chip microwave circulator with size 1 /1000 th the wavelength by exploiting the chiral, "slow-light" response of a two-dimensional electron gas in the quantum Hall regime. For an integrated GaAs device with 330 μ m diameter and about 1-GHz center frequency, a nonreciprocity of 25 dB is observed over a 50-MHz bandwidth. Furthermore, the nonreciprocity can be dynamically tuned by varying the voltage at the port, an aspect that may enable reconfigurable passive routing of microwave signals on chip.

  8. Posterior circulation revascularization to manage vertebrobasilar occlusion

    Directory of Open Access Journals (Sweden)

    SHANG Yan-guo

    2012-06-01

    Full Text Available Objective To discuss the technique and effect of posterior circulation revascularization to manage vertebrobasilar occlusion. Methods Nine patients with vertebrobasilar occlusion were treated by using occipital artery-posterior inferior cerebellar artery bypass, superficial temporal artery-superior cerebellar artery bypass, superficial temporal artery-posterior cerebral artery bypass and occipital artery-vertebral artery bypass with radial artery graft. Results Intraoperative indocyanine green angiography showed all the bypass arteries were patent. Postoperative DSA or CTA showed bypass arteries patent in 8 patients, among whom seven patients got obvious improvement on MR or CT perfusion. One patient died of heart failure on the 15th day postoperative. During the follow-up of eight patients, no stroke reoccurred, four patients got back to nearly normal life. Conclusion Most of the patients with vertebrobasilar occlusion could benefit from the posterior circulation revascularization, which should be confirmed by randomized controlled clinical trials in the future.

  9. Congenital cardiovascular malformations and the fetal circulation.

    Science.gov (United States)

    Rudolph, A M

    2010-03-01

    After birth, gas exchange is achieved in the lung, whereas prenatally it occurs in the placenta. This is associated with differences in blood flow patterns in the fetus as compared with the postnatal circulation. Congenital cardiovascular malformations are associated with haemodynamic changes in the fetus, which differ from those occurring postnatally. Obstruction to cardiac outflow may alter myocardial development, resulting in progressive ventricular hypoplasia. Alteration of oxygen content may profoundly influence pulmonary vascular and ductus arteriosus responses. Interference in blood flow and oxygen content may affect cerebral development as a result of inadequate oxygen or energy substrate supply. The circulatory effects may be gestational dependent, related to maturation of vascular responses in different organs. These prenatal influences of congenital cardiac defects may severely affect immediate, as well as longterm, postnatal prognosis and survival. This has stimulated the development of techniques for palliation of disturbed circulation during fetal life.

  10. 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.

  11. Formation and plasma circulation of solar prominences

    CERN Document Server

    Xia, Chun

    2016-01-01

    Solar prominences are long-lived cool and dense plasma curtains in the hot and rarefied outer solar atmosphere or corona. The physical mechanism responsible for their formation and especially for their internal plasma circulation has been uncertain for decades. The observed ubiquitous down flows in quiescent prominences are difficult to interpret as plasma with high conductivity seems to move across horizontal magnetic field lines. Here we present three-dimensional numerical simulations of prominence formation and evolution in an elongated magnetic flux rope as a result of in-situ plasma condensations fueled by continuous plasma evaporation from the solar chromosphere. The prominence is born and maintained in a fragmented, highly dynamic state with continuous reappearance of multiple blobs and thread structures that move mainly downward dragging along mass-loaded field lines. The prominence plasma circulation is characterized by the dynamic balance between the drainage of prominence plasma back to the chromos...

  12. Circulation control STOL aircraft design aspects

    Science.gov (United States)

    Loth, John L.

    1987-01-01

    Since Davidson patented Circulation Control Airfoils in 1960, there have been only 2 aircraft designed and flown with circulation control (CC). Designing with CC is complex for the following reasons: the relation between lift increase and blowing momentum is nonlinear; for good cruise performance one must change the wing geometry in flight from a round to a sharp trailing edge. The bleed air from the propulsion engines or an auxiliary compressor, must be used efficiently. In designing with CC, the propulsion and control aspects are just as important as aerodynamics. These design aspects were examined and linearized equations are presented in order to facilitate a preliminary analysis of the performance potential of CC. The thrust and lift requirements for takeoff make the calculated runway length very sensitive to the bleed air ratio. Thrust vectoring improves performance and can offset nose down pitching moments. The choice of blowing jet to free stream velocity ratio determines the efficiency of applying bleed air power.

  13. [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.

  14. First circulating beam in the AA

    CERN Multimedia

    1980-01-01

    On 3 July 1980, two years after project authorization, beam circulated for the first time in the AA. It was a 3.5 GeV/c proton test beam. We see an expecting crowd, minutes before the happy event. The persons are to numerous to name them all. Heribert Koziol, apparently asleep, is answering the call from an impatient director. See also 8007094.

  15. Cluster Dynamics in a Circulating Fluidized Bed

    Energy Technology Data Exchange (ETDEWEB)

    Guenther, C.P.; Breault, R.W.

    2006-11-01

    A common hydrodynamic feature in industrial scale circulating fluidized beds is the presence of clusters. The continuous formation and destruction of clusters strongly influences particle hold-up, pressure drop, heat transfer at the wall, and mixing. In this paper fiber optic data is analyzed using discrete wavelet analysis to characterize the dynamic behavior of clusters. Five radial positions at three different axial locations under five different operating were analyzed using discrete wavelets. Results are summarized with respect to cluster size and frequency.

  16. NUCLA Circulating Atmospheric Fluidized Bed Demonstration Project

    Energy Technology Data Exchange (ETDEWEB)

    1992-02-01

    The objective of this DOE Cooperative Agreement is to conduct a cost-shared clean coal technology project to demonstrate the feasibility of circulating fluidized bed combustion technology and to evaluate economic, environmental, and operational benefits of CFB steam generators on a utility scale. At the conclusion of the Phase 2 program, testing related to satisfying these objectives was completed. Data analysis and reporting are scheduled for completion by October 1991. (VC)

  17. FORMATION AND PLASMA CIRCULATION OF SOLAR PROMINENCES

    OpenAIRE

    Xia, Chun; Keppens, Rony

    2016-01-01

    Solar prominences are long-lived cool and dense plasma curtains in the hot and rarefied outer solar atmosphere or corona. The physical mechanism responsible for their formation and especially for their internal plasma circulation has been uncertain for decades. The observed ubiquitous down flows in quiescent prominences are difficult to interpret as plasma with high conductivity seems to move across horizontal magnetic field lines. Here we present three-dimensional numerical simulations of pr...

  18. On circulant states with positive partial transpose

    OpenAIRE

    Chruściński, Dariusz; Kossakowski, Andrzej

    2007-01-01

    We construct a large class of quantum "d x d" states which are positive under partial transposition (so called PPT states). The construction is based on certain direct sum decomposition of the total Hilbert space displaying characteristic circular structure - that is way we call them circulant states. It turns out that partial transposition maps any such decomposition into another one and hence both original density matrix and its partially transposed partner share similar cyclic properties. ...

  19. 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.

  20. The creation and circulation of public geographies

    OpenAIRE

    Kitchin, Rob; Linehan, Denis; O'Callaghan, Cian; Lawton, Philip

    2013-01-01

    In response to the commentaries, we discuss further how social media disrupts and remakes the creation and circulation of geographical knowledges and potentially reconfigures the moral economy of the social sciences. In particular, we examine questions of what is meant by public geography, the publics which such geographies serve, alternative and complementary approaches to social media, the politics of authorship within collective blogs, the politics and mechanisms of knowledge c...

  1. Circulating fluidized bed boilers design and operations

    CERN Document Server

    Basu, Prabir

    1991-01-01

    This book provides practicing engineers and students with insight into the design and operation of circulating fluidized bed (CFB) boilers. Through a combination of theoretical concepts and practical experience, this book gives the reader a basic understanding of the many aspects of this subject.Important environmental considerations, including solid waste disposal and predicted emissions, are addressed individually in separate chapters. This book places an emphasis on combustion, hydrodynamics, heat transfer, and material issues, and illustrates these concepts with numerous examples of pres

  2. Circulation in a Short Cylindrical Couette System

    Energy Technology Data Exchange (ETDEWEB)

    Akira Kageyama; Hantao Ji; Jeremy Goodman

    2003-07-08

    In preparation for an experimental study of magnetorotational instability (MRI) in liquid metal, we explore Couette flows having height comparable to the gap between cylinders, centrifugally stable rotation, and high Reynolds number. Experiments in water are compared with numerical simulations. The flow is very different from that of an ideal, infinitely long Couette system. Simulations show that endcaps co-rotating with the outer cylinder drive a strong poloidal circulation that redistributes angular momentum. Predicted toroidal flow profiles agree well with experimental measurements. Spin-down times scale with Reynolds number as expected for laminar Ekman circulation; extrapolation from two-dimensional simulations at Re less than or equal to 3200 agrees remarkably well with experiment at Re approximately equal to 106. This suggests that turbulence does not dominate the effective viscosity. Further detailed numerical studies reveal a strong radially inward flow near both endcaps. After turning vertically along the inner cylinder, these flows converge at the midplane and depart the boundary in a radial jet. To minimize this circulation in the MRI experiment, endcaps consisting of multiple, differentially rotating rings are proposed. Simulations predict that an adequate approximation to the ideal Couette profile can be obtained with a few rings.

  3. The protein corona of circulating PEGylated liposomes.

    Science.gov (United States)

    Palchetti, Sara; Colapicchioni, Valentina; Digiacomo, Luca; Caracciolo, Giulio; Pozzi, Daniela; Capriotti, Anna Laura; La Barbera, Giorgia; Laganà, Aldo

    2016-02-01

    Following systemic administration, liposomes are covered by a 'corona' of proteins, and preserving the surface functionality is challenging. Coating the liposome surface with polyethylene glycol (PEG) is the most widely used anti-opsonization strategy, but it cannot fully preclude protein adsorption. To date, protein binding has been studied following in vitro incubation to predict the fate of liposomes in vivo, while dynamic incubation mimicking in vivo conditions remains largely unexplored. The main aim of this investigation was to determine whether shear stress, produced by physiologically relevant dynamic flow, could influence the liposome-protein corona. The corona of circulating PEGylated liposome was thoroughly compared with that formed by incubation in vitro. Systematic comparison in terms of size, surface charge and quantitative composition was made by dynamic light scattering, microelectrophoresis and nano-liquid chromatography tandem mass spectrometry (nanoLC-MS/MS). Size of coronas formed under static vs. dynamic incubation did not appreciably differ from each other. On the other side, the corona of circulating liposomes was more negatively charged than its static counterpart. Of note, the variety of protein species in the corona formed in a dynamic flow was significantly wider. Collectively, these results demonstrated that the corona of circulating PEGylated liposomes can be considerably different from that formed in a static fluid. This seems to be a key factor to predict the biological activity of a liposomal formulation in a physiological environment.

  4. Elevated circulating somatostatin levels in acromegaly.

    Science.gov (United States)

    Arosio, M; Porretti, S; Epaminonda, P; Giavoli, C; Gebbia, C; Penati, C; Beck-Peccoz, P; Peracchi, M

    2003-06-01

    GH increases hypothalamic somatostatin (SS) synthesis and secretion but it is unknown if chronic GH excess, as found in acromegaly, may influence circulating SS levels, that are mainly of enteropancreatic source and affect several gastrointestinal functions, including motility. Circulating SS occurs in several post-translational forms including somatostatin-14 (SS-14), somatostatin-28 (SS-28) and other small peptides. The aim of the present study was to characterize the fasting and postprandial pattern of plasma circulating somatostatin in normal subjects and patients with acromegaly. Fasting total SS and SS-28 levels were measured in 32 subjects, 16 acromegalic patients with a new diagnosis (A) (8 F, 8 M, median age 48) and 16 matched healthy volunteers (C) (8 F, 8 M, median age 45). SS was also determined after a standard solid-liquid meal (550 kCal) in 24 of the subjects (12 C and 12 A). Fasting SS and SS-28 were significantly higher in acromegalic patients as compared to healthy subjects. In the former, a positive correlation was found between IGF-I and SS levels (r = 0.525 p acromegaly. Excess GH/IGF-I could be a causal factor in somatostatin hypersecretion. Conceivably this abnormality might play a role in some alterations of gastrointestinal function of acromegalic patients such as prolonged bowel transit.

  5. Global Circulation and Impact of Plasmaspheric Plumes

    Science.gov (United States)

    Moore, Thomas E.; Fok, Mei-Ching; Chen, Sheng-Hsiem; Delcourt, Dominique C.; Fedder, Joel A.; Slinker, Steven P.

    2008-01-01

    We report results from the global circulation model of Lyon, Fedder, and Mobarry with an embedded model of the inner magnetosphere including the plasmasphere. The combination is used to initiate large numbers of representative protons on the geosynchronous orbit L shell, to assign particle weightings, to track their: subsequent trajectories in the 3D fields. This permits us to study the global circulation of plasmaspheric plumes and to compare these with Polar observations from the dayside magnetopause region . A range of events is studied from an isolated period of SBz in the solar wind,to a large storm sequence. We consider effects on circulating plasma reaching the dayside reconnection X-line, the population of the plasma sheet with ionospheric protons and the generation of ring current pressure from this source, compared with solar wind, polar wind, and auroral wind sources. We find that the transient plasmaspheric plume source is large in terms of total fluence, but of modest proportions in terms of contribution to the ring current. Implications of this and other results for improved space weather modeling and prediction will be discussed.

  6. When Prostate Cancer Circulates in the Bloodstream

    Directory of Open Access Journals (Sweden)

    Virginie Vlaeminck-Guillem

    2015-10-01

    Full Text Available Management of patients with prostate cancer is currently based on imperfect clinical, biological, radiological and pathological evaluation. Prostate cancer aggressiveness, including metastatic potential, remains difficult to accurately estimate. In an attempt to better adapt therapeutics to an individual (personalized medicine, reliable evaluation of the intrinsic molecular biology of the tumor is warranted, and particularly for all tumor sites (primary tumors and secondary sites at any time of the disease progression. As a consequence of their natural tendency to grow (passive invasion or as a consequence of an active blood vessel invasion by metastase-initiating cells, tumors shed various materials into the bloodstream. Major efforts have been recently made to develop powerful and accurate methods able to detect, quantify and/or analyze all these circulating tumor materials: circulating tumors cells, disseminating tumor cells, extracellular vesicles (including exosomes, nucleic acids, etc. The aim of this review is to summarize current knowledge about these circulating tumor materials and their applications in translational research.

  7. 19 CFR 207.63 - Circulation of draft questionnaires.

    Science.gov (United States)

    2010-04-01

    ... 19 Customs Duties 3 2010-04-01 2010-04-01 false Circulation of draft questionnaires. 207.63... SUBSIDIZED EXPORTS TO THE UNITED STATES Five-Year Reviews § 207.63 Circulation of draft questionnaires. (a) The Director shall circulate draft questionnaires to the parties for comment in each full review....

  8. Circulator Integrated in Low Temperature Co-fired Ceramics Technology

    NARCIS (Netherlands)

    Dijk, R. van; Bent, G. van der; Ashari, M.; McKay, M.

    2014-01-01

    We present a demonstration of an integrated circulator for TR modules using low temperature co-fired ceramic (LTCC) technology. Two different circulators have been realised to be used in TR modules in two different frequency bands, C-and Ku-band. The circulator is a three-port junction microstrip ty

  9. Clinical profile and prognosis of patients with posterior circulation stroke

    Directory of Open Access Journals (Sweden)

    Kavita J. Rawat

    2016-12-01

    Conclusions: Posterior circulation stroke present with a wide variety of symptoms. Episodes are often staggering and more protracted than those of anterior circulation stroke. Further studies are needed to determine the safest and most effective treatment modalities for the various types of posterior circulation stroke. [Int J Res Med Sci 2016; 4(12.000: 5159-5164

  10. Computer-aided design of stripline ferrite junction circulators

    Science.gov (United States)

    Uzdy, Z.

    1980-01-01

    A general design procedure is presented for stripline Y-junction circulators employing solid dielectric between ground planes. The resonator design and impedance matching are derived in a form suitable for computer evaluation. The procedure is applicable to cases where either the circulator bandwidth or the ground plane spacing is specified. An experimental S-band switching circulator design illustrates the technique.

  11. Algorithms for Finding the Inverses of Factor Block Circulant Matrices

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    In this paper, algorithms for finding the inverse of a factor block circulant matrix,a factor block retrocirculant matrix and partitioned matrix with factor block circulant blocks over the complex field are presented respectively. In addition, two algorithms for the inverse of a factor block circulant matrix over the quaternion division algebra are proposed.

  12. Elevated levels of circulating DNA in cardiovascular disease patients: metagenomic profiling of microbiome in the circulation.

    Science.gov (United States)

    Dinakaran, Vasudevan; Rathinavel, Andiappan; Pushpanathan, Muthuirulan; Sivakumar, Ramamoorthy; Gunasekaran, Paramasamy; Rajendhran, Jeyaprakash

    2014-01-01

    Cardiovascular diseases (CVDs) are the leading cause of death worldwide. An expanding body of evidence supports the role of human microbiome in the establishment of CVDs and, this has gained much attention recently. This work was aimed to study the circulating human microbiome in CVD patients and healthy subjects. The levels of circulating cell free DNA (circDNA) was higher in CVD patients (n = 80) than in healthy controls (n = 40). More specifically, the relative levels of circulating bacterial DNA and the ratio of 16S rRNA/β-globin gene copy numbers were higher in the circulation of CVD patients than healthy individuals. In addition, we found a higher circulating microbial diversity in CVD patients (n = 3) in comparison to healthy individuals (n = 3) by deep shotgun sequencing. At the phylum level, we observed a dominance of Actinobacteria in CVD patients, followed by Proteobacteria, in contrast to that in healthy controls, where Proteobacteria was predominantly enriched, followed by Actinobacteria. The circulating virome in CVD patients was enriched with bacteriophages with a preponderance of Propionibacterium phages, followed by Pseudomonas phages and Rhizobium phages in contrast to that in healthy individuals, where a relatively greater abundance of eukaryotic viruses dominated by Lymphocystis virus (LCV) and Torque Teno viruses (TTV) was observed. Thus, the release of bacterial and viral DNA elements in the circulation could play a major role leading to elevated circDNA levels in CVD patients. The increased circDNA levels could be either the cause or consequence of CVD incidence, which needs to be explored further.

  13. Formation of germline chimera Gaok chicken used circulation primordial germ cells (circulation PGCs fresh and thawed

    Directory of Open Access Journals (Sweden)

    Kostaman T

    2014-03-01

    Full Text Available Formation of germline chimeras by transfer of chicken primordial germ cells (PGCs is one of the effective techniques for preservation and regeneration of genetic resources in chickens. This study attempted to form germline chimeras of Gaok chicken buy purifying circulated PGCs of donor embryo before it is transferred to the recipient (White Leghorn chickens=WL and studied the ability of recipient embryo on survival in incubators, and hatchability. This study used 200 fertile eggs of Gaok and 90 fertile WL breed all of the eggs was incubated at 380C and 60% humidity in a portable incubator. PGCs-circulation of the blood collected Gaok embryos at stage 14-16 were taken from the dorsal aorta, and then purified by centrifugation method using nycodenz. PGCs-circulation results further purification frozen in liquid nitrogen before being transferred to the recipient embryo. The results showed that for the development of embryos transferred to the fresh circulation of PGCs-circulation as many as 25 cells can survive up to day 14, while one of the transferred of 50 and 100 cells into recipient embryos was hatched (10%. On the contrari recipient embryos that are transferred to the frozen PGCs-circulation the embryos development was shorter, and only survived until day 10th (treatment 25 cells, day 14th (treatment of 50 cells and day 17th (treatment of 100 cells. It is concluded that the amount of PGCs-circulation embryos transferred to the recipient is one factor that influence the success of the development germline chimeras.

  14. Translation of the model plant of the CN code TRAC-BF1 Cofrentes of a SNAP-TRACE; Traduccion del modelo de planta de CN Cofrentes del codigo TRAC-BF1 a SNAP-TRACE

    Energy Technology Data Exchange (ETDEWEB)

    Escriva, A.; Munuz-Cobo, J. L.; Concejal, A.; Melara, J.; Albendea, M.

    2012-07-01

    It aims to develop a three-dimensional model of the CN Cofrentes whose consistent results Compared with those in current use programs (TRAC-BFl, RETRAN) validated with data of the plant. This comparison should be done globally and that you can not carry a compensation of errors. To check the correct translation of the results obtained have been compared with TRACE and the programs currently in use and the relevant adjustments have been made, taking into account that both the correlations and models are different codes. During the completion of this work we have detected several errors that must be corrected in future versions of these tools.

  15. 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.

  16. Explicit Determinants of the RFPrLrR Circulant and RLPrFrL Circulant Matrices Involving Some Famous Numbers

    Directory of Open Access Journals (Sweden)

    Tingting Xu

    2014-01-01

    Full Text Available Circulant matrices may play a crucial role in solving various differential equations. In this paper, the techniques used herein are based on the inverse factorization of polynomial. We give the explicit determinants of the RFPrLrR circulant matrices and RLPrFrL circulant matrices involving Fibonacci, Lucas, Pell, and Pell-Lucas number, respectively.

  17. Effect of vegetation on the Late Miocene ocean circulation

    Directory of Open Access Journals (Sweden)

    G. Lohmann

    2006-08-01

    Full Text Available A weak and shallow thermohaline circulation in the North Atlantic Ocean is related to an open Central American gateway and exchange with fresh Pacific waters. We estimate the effect of vegetation on the ocean general circulation using the atmospheric circulation model simulations for the Late Miocene climate. Caused by an increase in net evaporation in the Miocene North Atlantic, the North Atlantic water becomes more saline which enhances the overturning circulation and thus the northward heat transport. This effect reveals a potentially important feedback between the ocean circulation, the hydrological cycle and the land surface cover for Cenozoic climate evolution.

  18. Gas cooled fast breeder reactor design for a circulator test facility (modified HTGR circulator test facility)

    Energy Technology Data Exchange (ETDEWEB)

    1979-10-01

    A GCFR helium circulator test facility sized for full design conditions is proposed for meeting the above requirements. The circulator will be mounted in a large vessel containing high pressure helium which will permit testing at the same power, speed, pressure, temperature and flow conditions intended in the demonstration plant. The electric drive motor for the circulator will obtain its power from an electric supply and distribution system in which electric power will be taken from a local utility. The conceptual design decribed in this report is the result of close interaction between the General Atomic Company (GA), designer of the GCFR, and The Ralph M. Parson Company, architect/engineer for the test facility. A realistic estimate of total project cost is presented, together with a schedule for design, procurement, construction, and inspection.

  19. Effect of slip on circulation inside a droplet

    CERN Document Server

    Thalakkottor, Joseph J

    2013-01-01

    Internal recirculation in a moving droplet plays an important role in several droplet-based microfluidic devices as it enhances mixing, chemical reaction and heat transfer. The occurrence of fluid slip at the wall, which becomes prominent at high shear rates and lower length scales, results in a significant change in droplet circulation. Using molecular dynamics (MD) simulations, the presence of circulation in droplets is demonstrated and quantified. Circulation is shown to vary inversely with slip length, which is a measure of interface wettability. A simple circulation model is established that captures the effect of slip on droplet circulation. Scaling parameters for circulation and slip length are identified from the circulation model which leads to the collapse of data for droplets with varying aspect ratio (AR) and slip length. The model is validated using continuum and MD simulations and is shown to be accurate for droplets with high AR.

  20. Atmospheric General Circulation Changes under Global Warming

    Science.gov (United States)

    Palipane, Erool

    The work in this thesis is mainly two-fold. First we study the internal variability of the general circulation and focus our study on the annular modes and how important it is to simulate the subsynoptic scales in the circulation. In the next major section we will try to understand the mechanisms of the forced response and the mechanisms leading towards the jet shift from transient evolution in Atmospheric general circulation models. In the first part, in an attempt to assess the benefit of resolving the sub-synoptic to mesoscale processes, the spatial and temporal characteristics of the Annular Modes (AMs), in particular those related to the troposphere-stratosphere interaction, are evaluated for moderate- and high-horizontal resolution simulations with a global atmospheric general circulation model (AGCM), in comparison with the ERA40 re- analysis. Relative to the CMIP-type climate models, the IFS AGCM demonstrates notable improvement in capturing the key characteristics of the AMs. Notably, the performance with the high horizontal resolution version of the model is systematically superior to the moderate resolution on all metrics examined, including the variance of the AMs at different seasons of the year, the intrinsic e-folding time scales of the AMs, and the downward influence from the stratosphere to troposphere in the AMs. Moreover, the high-resolution simulation with a greater persistence in the intrinsic variability of the SAM projects an appreciably larger shift of the surface westerly wind during the Southern Hemisphere summer under climate change. In the second part, the response of the atmospheric circulation to greenhouse gas-induced SST warming is investigated using large ensemble experiments with two AGCMs, with a focus on the robust feature of the poleward shift of the eddy driven jet. In these experiments, large ensembles of simulations are conducted by abruptly switching the SST forcing on from January 1st to focus on the wintertime circulation

  1. Pure midbrain ischemia and hypoplastic vertebrobasilar circulation.

    Science.gov (United States)

    Gilberti, Nicola; Gamba, Massimo; Costa, Angelo; Vergani, Veronica; Spezi, Raffaella; Pezzini, Alessandro; Volonghi, Irene; Mardighian, Dikran; Gasparotti, Roberto; Padovani, Alessandro; Magoni, Mauro

    2014-02-01

    Isolated midbrain infarction is rare and little is known about etiology and patient's long-term follow up. We aimed to describe the clinical features, the causative diseases and the outcome of patients with isolated midbrain infarction who were admitted to our center, focusing on vascular abnormalities of posterior circulation. All patients with first acute ischemic stroke limited to the midbrain were included and their demographic features, neurological symptoms, neuroimaging data, and cardiovascular risk factors were recorded. Functional outcome, using modified Rankin scale, was assessed at discharge and at the 3 month follow up evaluation. We found nine patients with acute isolated midbrain infarction, representing 0.61 % of all ischemic stroke admitted to our center. The most common cause of stroke was small-vessel disease (88.8 %). At stroke onset, none of the patients had consciousness disturbances, and four patients (44.4 %) had gait impairment, five patients (55.5 %) presented with diplopia due to involvement of the third nerve or fascicular type of third-nerve palsy, seven patients (77.7 %) had vascular anomalies of vertebrobasilar circulation: the most frequent was vertebral artery hypoplasia [four patients (44.4 %)]. At follow up evaluation, seven patients (77.7 %) had a good functional outcome and no patients experienced recurrence of cerebrovascular events. As isolated midbrain infarction is uncommon, specific ocular motor signs, mainly third-nerve palsy, may help to identify and localize the mesencephalic infarct. Abnormalities in vertebrobasilar circulation, such as hypoplastic basilar or vertebral artery, are frequently associated with isolated midbrain ischemia. The hypoplastic vertebrobasilar system may predispose to posterior ischemic stroke.

  2. Microsurgical management of posterior circulation aneurysms

    Directory of Open Access Journals (Sweden)

    SHI Xiang-en

    2012-02-01

    Full Text Available Objective To retrospectively analyze effective methods for surgical management of posterior circulation aneurysms. Methods There were 42 patients with posterior circulation aneurysms [26 cases of basilar aneurysm (27 aneurysms, 16 cases of vertebral aneurysm (17 aneurysms]. There were 15 patients underwent bypass surgery [4 external carotid artery-P2 segment of posterior cerebral artery (ECA-P2, 2 internal carotid artery-P2 segment of posterior cerebral artery (ICA-P2, 2 internal maxillary artery-P2 segment of posterior cerebral artery (IMA-P2, 2 intracranial segment of vertebral artery-extracranial segment of vertebral artery, 5 occipital artery-posterior inferior cerebellar artery (OA-PICA] and 27 patients underwent simple surgical clipping. Results Activities of daily life of 37 patients recovered to normal (14 patients with aneurysm on the top of basilar artery, 3 with aneurysm on the trunk of basilar artery, 9 with vertebral aneurysm, 5 with posterior inferior cerebellar artery aneurysm, 4 with aneurysm on the junction of P1-P2 segment of posterior cerebral artery, 1 with superior cerebellar artery, and 1 with anterior inferior cerebellar aneurysm. None of them occurred operation-related neurological dysfunction. The recovery rate was 88.09% . Among the other patients, 1 with aneurysm on the top of basilar artery presented severe signs and symptoms of neurological defect and cannot take care of oneself, 2 patients (1 with aneurysm on the top of basilar artery, 1 with aneurysm on the trunk of basilar artery occurred brain stem hemorrhage after operation, and died at perioperative period, 2 with vertebral aneurysm relapsed and was cured after treatment. Conclusion Posterior circulation aneurysm which is not suitable for surgical clipping can be treated with intra? and extra?cranial vessel bypass. It may avoid the risk of surgical clipping of aneurysm.

  3. Bay of Campeche circulation: An update

    Science.gov (United States)

    Vázquez de la Cerda, A. M.; Reid, R. O.; DiMarco, S. F.; Jochens, A. E.

    We address four independent sources of observational evidence pertaining to circulation in the Bay of Campeche (BOC), located south of 23°N in the western Gulf of Mexico, with the objective of characterizing its mean circulation, its variability, and the probable forcing thereof. The observational information includes historic hydrographic and dissolved oxygen data, Lagrangian current data, satellite-derived sea surface height anomaly (SSHA), and special observations of marine winds in the BOC. The hydrographic data reveals that the mean surface circulation relative to 425 db and to 800 db includes a weak cyclone with cyclic transport of about 4×106 m3 · s-1. Ten years of near-surface drifter observations shows a statistically meaningful mean cyclonic pattern of current with westward intensification that is consistent with the mean surface dynamic topography relative to 800 db. Observations of mean currents in the BOC at 900 m based on deep floats by G. L. Weatherly and others allows estimation of the current shear from the Lagrangian data and this is geostrophically consistent with that from the dynamic topography relative to 800 m. The mean cyclonic wind stress curl field deduced from two sources of marine wind data indicate a forced Sverdrup transport consistent with that observed. Moreover a seasonal cycle is suggested in the near surface drifter data that is coherent with the seasonal signal in the wind stress curl. Finally, the historic SSHA for a period of over 8 years in the 1990s allows a characterization of the dominant empirical spatial patterns and their temporal variability.

  4. On circulating power of steady state tokamaks

    Energy Technology Data Exchange (ETDEWEB)

    Itoh, Kimitaka [National Inst. for Fusion Science, Nagoya (Japan); Itoh, Sanae; Fukuyama, Atsushi; Yagi, Masatoshi

    1996-03-01

    Circulating power for the sustenance and profile control of the steady state tokamak plasmas is discussed. The simultaneous fulfillment of the MHD stability at high beta value, the improved confinement and the stationary equilibrium requires the rotation drive as well as the current drive. In addition to the current drive efficiency, the efficiency for the rotation drive is investigated. The direct rotation drive by the external torque, such as the case of beam injection, is not efficient enough. The mechanism and the magnitude of the spontaneous plasma rotation are studied. (author)

  5. Transients in a circulating fluidized bed boiler

    Science.gov (United States)

    Baskakov, A. P.; Munts, V. A.; Pavlyuk, E. Yu.

    2013-11-01

    Transients in a circulating fluidized bed boiler firing biomass are considered. An attempt is made to describe transients with the use of concepts applied in the automatic control theory. The parameters calculated from an analysis of unsteady heat balance equations are compared with the experimental data obtained in the 12-MW boiler of the Chalmers University of Technology. It is demonstrated that these equations describe the transient modes of operation with good accuracy. Dependences for calculating the time constants of unsteady processes are obtained.

  6. Non-singular circulant graphs and digraphs

    CERN Document Server

    Lal, A K

    2011-01-01

    We give necessary and sufficient conditions for a few classes of circulant graphs/digraphs to be singular. We also give two generalizations of the above graphs/digraphs, namely $(r,s,t)$-digraphs for non-negative integers $r,s$ and $t$, and the digraph $C_n^{i,j,k,l}$ with certain restrictions. A necessary and sufficient condition for the digraphs $C_n^{i,j,k,l}$ to be singular is obtained. Some necessary conditions are given under which the $(r,s,t)$-digraphs are singular.

  7. Is the thermohaline circulation really at risk?

    OpenAIRE

    Quadfasel, Detlef

    2012-01-01

    Changes in thermohaline circulation (THC) have been known to change the European and Arctic climate within decades. Knowing if, when, and how a major change in the THC might occur in the mid-term might enable both the public and the private sectors to understand the risks, time horizon, and possible scenarios of major changes in the climate and to adapt to them. The THOR project has been running from 2008 to 2012 and has been investigating on determining how the THC impacts climate stabili...

  8. Nucla circulating atmospheric fluidized bed demonstration project

    Energy Technology Data Exchange (ETDEWEB)

    1991-01-31

    During the fourth quarter of 1990, steady-state performance testing at the Nucla Circulating Fluidized Bed (CFB) resumed under sponsorship of the US Department of Energy. Co-sponsorship of the Demonstration Test Program by the Electric Power Research Institute (EPRI) was completed on June 15, 1990. From October through December, 1990, Colorado-Ute Electric Association (CUEA) completed a total of 23 steady-state performance tests, 4 dynamic tests, and set operating records during November and December as the result of improved unit operating reliability. Highlight events and achievements during this period of operation are presented.

  9. Circulant states with positive partial transpose

    Science.gov (United States)

    Chruściński, Dariusz; Kossakowski, Andrzej

    2007-09-01

    We construct a large class of quantum d⊗d states which are positive under partial transposition (so called PPT states). The construction is based on certain direct sum decomposition of the total Hilbert space displaying characteristic circular structure—that is why we call them circulant states. It turns out that partial transposition maps any such decomposition into another one and hence both original density matrix and its partially transposed partner share similar cyclic properties. This class contains many well-known examples of PPT states from the literature and gives rise to a huge family of completely new states.

  10. Effects of Buoyancy on Langmuir Circulation

    Institute of Scientific and Technical Information of China (English)

    SONG Jun; SONG Jin-Bao

    2008-01-01

    Based on the Navier-Stokes equation,an equation describing the Langmuir circulation is derived by a perturbation method when the influences of Coriolis force and buoyancy force are both considered.The approach used in the analysis is similar to the works carried out by Craik and Leibovich[J.Fluid Mech.73 (1976)401],Leibovich [J.Fluid Mech.79 (1977) 715]and Huang[J.Fluid Mech.91 (1979) 191].Potential applications of the equation proposed are discussed in the area of Antarctic circumpolar current.

  11. Biodegradable long-circulating polymeric nanospheres.

    Science.gov (United States)

    Gref, R; Minamitake, Y; Peracchia, M T; Trubetskoy, V; Torchilin, V; Langer, R

    1994-03-18

    Injectable nanoparticulate carriers have important potential applications such as site-specific drug delivery or medical imaging. Conventional carriers, however, cannot generally be used because they are eliminated by the reticulo-endothelial system within seconds or minutes after intravenous injection. To address these limitations, monodisperse biodegradable nanospheres were developed from amphiphilic copolymers composed of two biocompatible blocks. The nanospheres exhibited dramatically increased blood circulation times and reduced liver accumulation in mice. Furthermore, they entrapped up to 45 percent by weight of the drug in the dense core in a one-step procedure and could be freeze-dried and easily redispersed without additives in aqueous solutions.

  12. Glioblastoma Circulating Cells: Reality, Trap or Illusion?

    Directory of Open Access Journals (Sweden)

    A. Lombard

    2015-01-01

    Full Text Available Metastases are the hallmark of cancer. This event is in direct relationship with the ability of cancer cells to leave the tumor mass and travel long distances within the bloodstream and/or lymphatic vessels. Glioblastoma multiforme (GBM, the most frequent primary brain neoplasm, is mainly characterized by a dismal prognosis. The usual fatal issue for GBM patients is a consequence of local recurrence that is observed most of the time without any distant metastases. However, it has recently been documented that GBM cells could be isolated from the bloodstream in several studies. This observation raises the question of the possible involvement of glioblastoma-circulating cells in GBM deadly recurrence by a “homing metastasis” process. Therefore, we think it is important to review the already known molecular mechanisms underlying circulating tumor cells (CTC specific properties, emphasizing their epithelial to mesenchymal transition (EMT abilities and their possible involvement in tumor initiation. The idea is here to review these mechanisms and speculate on how relevant they could be applied in the forthcoming battles against GBM.

  13. Formation and Plasma Circulation of Solar Prominences

    Science.gov (United States)

    Xia, C.; Keppens, R.

    2016-05-01

    Solar prominences are long-lived cool and dense plasma curtains in the hot and rarefied outer solar atmosphere or corona. The physical mechanism responsible for their formation and especially for their internal plasma circulation has been uncertain for decades. The observed ubiquitous downflows in quiescent prominences are difficult to interpret because plasma with high conductivity seems to move across horizontal magnetic field lines. Here we present three-dimensional numerical simulations of prominence formation and evolution in an elongated magnetic flux rope as a result of in situ plasma condensations fueled by continuous plasma evaporation from the solar chromosphere. The prominence is born and maintained in a fragmented, highly dynamic state with continuous reappearance of multiple blobs and thread structures that move mainly downward, dragging along mass-loaded field lines. The circulation of prominence plasma is characterized by the dynamic balance between the drainage of prominence plasma back to the chromosphere and the formation of prominence plasma via continuous condensation. Plasma evaporates from the chromosphere, condenses into the prominence in the corona, and drains back to the chromosphere, establishing a stable chromosphere-corona plasma cycle. Synthetic images of the modeled prominence with the Solar Dynamics Observatory Atmospheric Imaging Assembly closely resemble actual observations, with many dynamical threads underlying an elliptical coronal cavity.

  14. ENDEMIC ORTHOPOXVIRUS CIRCULATING IN PROCYONIDS IN MEXICO.

    Science.gov (United States)

    Gallardo-Romero, Nadia F; Aréchiga-Ceballos, Nidia; Emerson, Ginny L; Martínez-Martínez, Flor O; Doty, Jeffrey B; Nakazawa, Yoshinori J; Rendón-Franco, Emilio; Muñoz-García, Claudia I; Villanueva-García, Claudia; Ramírez-Cid, Citlali; Gama-Campillo, Lilia M; Gual-Sill, Fernando; Aguilar-Setién, Álvaro; Carroll, Darin S

    2016-07-01

    Limited serosurveillance studies suggested that orthopoxviruses (OPXV) are widespread in the US (e.g., Raccoonpox virus, Skunkpox virus, Volepox virus) and Brazil (Vaccinia virus); however, their animal reservoir(s) remain unconfirmed. Mexican mammal diversity includes several species related to those in which evidence for OPXV infections has been found (Oryzomys, Peromyscus, Microtus, and Procyonidae). The presence of these groups of mammals in Mexico and the evidence of their possible involvement in the maintenance of OPXV in nature suggest the same or similar OPXV are circulating in Mexico. We tested 201 sera from 129 procyonids via modified enzyme-linked immunosorbent assay (ELISA) and Western blot (WB) to estimate OPXV antibody prevalence in these animals. We detected a prevalence of 16.67% in Nasua narica (white-nosed coati), 35% in Procyon lotor (raccoon), and 30.4% in Bassariscus astutus (ring-tailed cat) when tested by either ELISA or WB. Western blot results presented protein bands consistent with the size of some OPXV immunodominant bands (14, 18, 32, 36, and 62 kDa). These results support the hypothesis that OPXV circulate in at least three genera of Procyonidae in Central and Southeast Mexico.

  15. The biology of circulating tumor cells.

    Science.gov (United States)

    Pantel, K; Speicher, M R

    2016-03-10

    Metastasis is a biologically complex process consisting of numerous stochastic events which may tremendously differ across various cancer types. Circulating tumor cells (CTCs) are cells that are shed from primary tumors and metastatic deposits into the blood stream. CTCs bear a tremendous potential to improve our understanding of steps involved in the metastatic cascade, starting from intravasation of tumor cells into the circulation until the formation of clinically detectable metastasis. These efforts were propelled by novel high-resolution approaches to dissect the genomes and transcriptomes of CTCs. Furthermore, capturing of viable CTCs has paved the way for innovative culturing technologies to study fundamental characteristics of CTCs such as invasiveness, their kinetics and responses to selection barriers, such as given therapies. Hence the study of CTCs is not only instrumental as a basic research tool, but also allows the serial monitoring of tumor genotypes and may therefore provide predictive and prognostic biomarkers for clinicians. Here, we review how CTCs have contributed to significant insights into the metastatic process and how they may be utilized in clinical practice.

  16. Measurement of cerebral circulation time in man

    Energy Technology Data Exchange (ETDEWEB)

    Celsis, P.; Chan, M.; Marc-Vergnes, J.P.; Leydet, P.; Viallard, G.; Charlet, J.P.; Danet, B.

    1985-05-01

    A simple, inexpensive method for measuring the cerebral circulation time (CCT) was developed. The CCT was considered to be equal to the time that an intravenously injected bolus of sodium pertechnetate Tc 99m took to go from the subclavian artery to the posterior venous confluence. The dilution curves were externally recorded at these two vessels. Particular attention was given to the curve treatment. The computer programmes were specially conceived in order to detect and, if possible, correct the experimental curve defects. Several reliability criteria were also defined in order to test the validity of each measurement. From a physiological point of view, the CCT is equal to the ratio of the global cerebral blood volume to the global cerebral blood flow. Thus, it can be widely applied in clinical research. For example, in a study of the relationship between CCT and age, sex and light cerebrovascular impairment, the technique was sensitive enough to discriminate between healthy subjects and patients suffering from-transient ischemic attack, or regressive stroke, and to show the action of a drug on the cerebral circulation in such patients.

  17. New England Medical Center Posterior Circulation registry.

    Science.gov (United States)

    Caplan, Louis R; Wityk, Robert J; Glass, Thomas A; Tapia, Jorge; Pazdera, Ladislav; Chang, Hui-Meng; Teal, Phillip; Dashe, John F; Chaves, Claudia J; Breen, Joan C; Vemmos, Kostas; Amarenco, Pierre; Tettenborn, Barbara; Leary, Megan; Estol, Conrad; Dewitt, L Dana; Pessin, Michael S

    2004-09-01

    Among 407 New England Medical Center Posterior Circulation registry patients, 59% had strokes without transient ischemic attacks (TIAs), 24% had TIAs then strokes, and 16% had only TIAs. Embolism was the commonest stroke mechanism (40% of patients including 24% cardiac origin, 14% intraarterial, 2% cardiac and arterial sources). In 32% large artery occlusive lesions caused hemodynamic brain ischemia. Infarcts most often included the distal posterior circulation territory (rostral brainstem, superior cerebellum and occipital and temporal lobes); the proximal (medulla and posterior inferior cerebellum) and middle (pons and anterior inferior cerebellum) territories were equally involved. Severe occlusive lesions (>50% stenosis) involved more than one large artery in 148 patients; 134 had one artery site involved unilaterally or bilaterally. The commonest occlusive sites were: extracranial vertebral artery (52 patients, 15 bilateral) intracranial vertebral artery (40 patients, 12 bilateral), basilar artery (46 patients). Intraarterial embolism was the commonest mechanism of brain infarction in patients with vertebral artery occlusive disease. Thirty-day mortality was 3.6%. Embolic mechanism, distal territory location, and basilar artery occlusive disease carried the poorest prognosis. The best outcome was in patients who had multiple arterial occlusive sites; they had position-sensitive TIAs during months to years.

  18. Numerical simulation of a natural circulation loop

    Energy Technology Data Exchange (ETDEWEB)

    Verissimo, Gabriel L.; Moreira, Maria de Lourdes; Faccini, Jose Luiz H., E-mail: gabrielverissimo@poli.ufrj.b, E-mail: malu@ien.gov.b, E-mail: faccini@ien.gov.b [Instituto de Engenharia Nuclear (IEN/CNEN-RJ), Rio de Janeiro, RJ (Brazil)

    2011-07-01

    This work presents a numerical simulation of a natural circulation loop using computational fluid dynamics. The simulated loop is an experimental model in a reduced scale of 1:10 of a passive heat removal system typical of advanced PWR reactors. The loop is composed of a heating vessel containing 52 electric heaters, a vertical shell-tube heat exchanger and a column of expansion. The working fluid is distilled water. Initially it was created a tridimensional geometric model of the loop components. After that, it was generated a tridimensional mesh of finite elements in order to calculate the variables of the problem. The boundaries of the numerical simulation were the power of the electric resistances and the cooling flow in the secondary side of the heat exchanger. The initial conditions were the temperature, the pressure and the fluid velocity at the time just before the power has been switched on. The results of this simulation were compared with the experimental data, in terms of the evolution of the temperatures in different locations of the loop, and of the average natural circulation flow as a function of time for a given power. (author)

  19. Circulating Tumor Cells Measurements in Hepatocellular Carcinoma

    Directory of Open Access Journals (Sweden)

    Franck Chiappini

    2012-01-01

    Full Text Available Liver cancer is the fifth most common cancer in men and the seventh in women. During the past 20 years, the incidence of HCC has tripled while the 5-year survival rate has remained below 12%. The presence of circulating tumor cells (CTC reflects the aggressiveness nature of a tumor. Many attempts have been made to develop assays that reliably detect and enumerate the CTC during the development of the HCC. In this case, the challenges are (1 there are few markers specific to the HCC (tumor cells versus nontumor cells and (2 they can be used to quantify the number of CTC in the bloodstream. Another technical challenge consists of finding few CTC mixed with million leukocytes and billion erythrocytes. CTC detection and identification can be used to estimate prognosis and may serve as an early marker to assess antitumor activity of treatment. CTC can also be used to predict progression-free survival and overall survival. CTC are an interesting source of biological information in order to understand dissemination, drug resistance, and treatment-induced cell death. Our aim is to review and analyze the different new methods existing to detect, enumerate, and characterize the CTC in the peripheral circulation of patients with HCC.

  20. Microsurgical anatomy of the posterior circulation

    Directory of Open Access Journals (Sweden)

    Pai Balaji

    2007-01-01

    Full Text Available Context: The microsurgical anatomy of the posterior circulation is very complex and variable. Surgical approaches to this area are considered risky due to the presence of the various important blood vessels and neural structures. Aims: To document the microsurgical anatomy of the posterior circulation along with variations in the Indian population. Materials and Methods: The authors studied 25 cadaveric brain specimens. Microsurgical dissection was carried out from the vertebral arteries to the basilar artery and its branches, the basilar artery bifurcation, posterior cerebral artery and its various branches. Measurements of the outer diameters of the vertebral artery, basilar artery and posterior cerebral artery and their lengths were taken. Results: The mean diameter of the vertebral artery was 3.4 mm on the left and 2.9 mm on the right. The diameter of the basilar artery varied from 3-7 mm (mean of 4.3 mm. The length varied from 24-35 mm (mean of 24.9 mm. The basilar artery gave off paramedian and circumferential perforating arteries. The origin of the anterior inferior cerebellar artery (AICA varied from 0-21 mm (mean 10.0 mm from the vertebrobasilar junction. The diameter of the AICA varied from being hypoplastic i.e., < 0.5 mm to 2 mm (mean 1.0 mm. The superior cerebellar artery (SCA arises very close to the basilar bifurcation, in our series (1-3 mm from the basilar artery bifurcation. The diameter of the SCA varied from 0.5-2.5 mm on both sides. The posterior cerebral artery (PCA is divided into four segments. The PCA gave rise to perforators (thalamoperforators, thalamogeniculate arteries, circumflex arteries and peduncular arteries, medial posterior choroidal artery, lateral posterior choroidal artery and cortical branches. In 39 specimens the P1 segment was found to be larger than the posterior communicating artery, in six specimens it was found to be equal to the diameter of the posterior communicating artery and in five specimens it

  1. Interannual variability of South American monsoon circulation

    Science.gov (United States)

    Alonso Gan, Manoel; Rafaele Araújo Lima, Jeane

    2016-04-01

    The South America Monsoon System (SAMS) is responsible for influencing the atmospheric circulation and precipitation over most of tropical South America (SA) during the summer season. Studies for aiming to understand the temporal variability of this system have great value to the scientific community, because the processes that control the monsoon climate are not totally clear. Thus, the main objective of this research is to investigate the possible large-scale climatic factors and the remote interaction mechanisms, which may be associated with summer season interannual variability focusing on identifying the main differences between dry and wet extremes rainy season in the South-eastern Amazon Basin (SAB), Central-West (WC) and Southeast (SE) of Brazil, which are areas influenced by the summer monsoon regime. For such analyzes, Pearson correlations, quantile method and composite analysis were used during the period from 1979 to 2014. The correlation between precipitation anomaly in SAB and the sea surface temperature anomaly (SSTA) and wind at 850hPa and 300hPa indicate El Niño-Southern Oscillation (ENSO) influence. Precipitation anomalies in WC did not show significant correlation with SSTA. However, a pattern similar to ENSO Modoki type was observed in the composite analysis. At 850 hPa, the presence of an anomalous cyclonic (anticyclonic) circulation was observed over the central region of SA during wet (dry) summers seasons. Over SE region of Brazil, a dipole SSTA pattern over the South Atlantic was identified, as well the presence of anomalous circulations with an equivalent barotropic structure over these SSTA areas. This pattern is more evident in case of dry summer on the SE. At 300 hPa, the wave train between 30°S-60°S was observed presenting a feature curvature from 120°W reaching SA, similar to the Pacific-South American pattern (PSA). Analysis of the summer interannual variability indicated the manifestation of wet summers more frequently than dry

  2. Two Types of Designs for On-Line Circulation Systems

    Directory of Open Access Journals (Sweden)

    Rob McGee

    1972-09-01

    Full Text Available On-line circulation systems divide into two types. One type contains records only for charged or otherwise absent items. The other contains a file of records for all titles or volumes in the library collection, regardless of their circulation status. This paper traces differences between the two types, examining different kinds of files and terminals, transaction evidence, the quality of bibliographic data, querying, and the possibility of functions outside circulation. Aspects of both operational and potential systems are considered.

  3. Stability of Thermohaline circulation with respect to fresh water release

    OpenAIRE

    Patwardhan, Ajay; Tewary, Vivek

    2008-01-01

    The relatively warm climate found in the North- Western Europe is due to the gulf stream that circulates warm saline water from southern latitudes to Europe. In North Atlantic ocean the stream gives out a large amount of heat, cools down and sinks to the bottom to complete the Thermohaline circulation. There is considerable debate on the stability of the stream to inputs of fresh water from the melting ice in Greenland and Arctic. The circulation, being switched off, will have massive impact ...

  4. 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.

  5. 输血后感染的HIV-1流行株分子流行病学调查%Molecular epidemiological investigation of HIV-1 circulating strain infected after blood receiving

    Institute of Scientific and Technical Information of China (English)

    赵翠英; 李保军; 陈素良; 邢辉; 路新利; 李巧敏; 白广义; 赵宏儒

    2011-01-01

    目的 了解河北省沙河市受血感染者及其夫妻传播者中HIV-1亚型特点和来源.方法 采集HIV-1感染者的全血样品,分离外周血单核细胞(PBMC),提取前病毒DNA,使用套式聚合酶链反应(nested-PCR),扩增HIV-1的env基因的C2~V3区,并进行序列测定和亚型分析.结果 对7例HIV-1感染者的血标本进行nested-PCR扩增,得到6份HIV-1 env C2~V3基因片段,经序列测定分析,6份样品均为B'亚型.组内基因离散率6.22%±1.38%,基因序列与云南瑞丽株RL42(泰国B亚型)相近.受血者Heb0224及其配偶Heb0223与云南瑞丽株RL42 env的基因离散率分别为3.93%和7.71%.结论 在河北省沙河市受血感染者及其夫妻传播者中流行的为HIV-1 B'亚型.%Objective To understand the characteristics and origin of subtypes of HIV-1 strains infected blood receivers and their couples in Shahe, Hebei Province. Methods The whole blood from HIV-1 infected individuals were collected and the peripheral blood mononuclear cell were separated. The provirus DNA was extracted and amplified by nested-PCR, after which the HIV-1 env C2~ V3 gene fragments was sequenced and its subtypes were analyzed. Results Among 7 HIV-1 antibody positive cases, 6 HIV-1 env C2~ V3 gene fragments were amplified and analyzed. 6 cases were confirmed to be infected with HIV-lsubtype B' strain. The genetic distance of HIV-1 B' intersubtype was 6.22 % ± 1.38% ( n = 6), their gene sequence were closely related to RL42 in Yunnan (Thailand B). To compare with RL42, the genetic distance of blood receiver (Heb0224) was 3.39 % and that of their spouses (Heb0223) was 7.71%. Conclusions HIV-1 subtype B' was the predominant subtype circulating among blood receivers and their spouses within families in Shahe, Hebei Province.

  6. [Harvey and his theory of circulation].

    Science.gov (United States)

    Wolters, Frank J

    2013-01-01

    In 1628 the English physician William Harvey (1578-1657) published his revolutionary theory that blood circulates through the body driven by the heart. This challenged the long-standing teachings of Hippocrates and Galen concerning 4 different bodily fluids or 'humours' that flowed through separate arterial and venous vascular systems. Harvey gained considerable influence in society as a member of the prestigious Royal College of Physicians in London and as personal physician to King James I and King Charles I. He strove for a more empirical foundation of medicine by means of anatomic demonstrations and vivisections. Despite enduring considerable criticism he managed to disseminate his ideas around the influential universities of Europe in the course of his lifetime. However, consequent changes in practice would not be brought about until decades after Harvey's death, when Galenist treatments such as blood-letting were gradually abandoned.

  7. Circulating Biomarkers for Duchenne Muscular Dystrophy

    Science.gov (United States)

    Aartsma-Rus, Annemieke; Spitali, Pietro

    2015-01-01

    Abstract Duchenne muscular dystrophy is the most common form of muscular dystrophy. Genetic and biochemical research over the years has characterized the cause, pathophysiology and development of the disease providing several potential therapeutic targets and/or biomarkers. High throughput – omic technologies have provided a comprehensive understanding of the changes occurring in dystrophic muscles. Murine and canine animal models have been a valuable source to profile muscles and body fluids, thus providing candidate biomarkers that can be evaluated in patients. This review will illustrate known circulating biomarkers that could track disease progression and response to therapy in patients affected by Duchenne muscular dystrophy. We present an overview of the transcriptomic, proteomic, metabolomics and lipidomic biomarkers described in literature. We show how studies in muscle tissue have led to the identification of serum and urine biomarkers and we highlight the importance of evaluating biomarkers as possible surrogate endpoints to facilitate regulatory processes for new medicinal products. PMID:27858763

  8. Bordetella pertussis: why is it still circulating?

    Science.gov (United States)

    Guiso, Nicole

    2014-01-01

    Bordetella pertussis is the causal agent of whooping cough, a highly contagious respiratory disease that is life-threatening in infants under the age of three months and may also be very severe in pregnant women and seniors. This disease can be prevented by vaccination but it remains a public health problem in many developed and developing countries.(1) So, why is B. pertussis still circulating? We need to consider several aspects of this vaccine-preventable disease when answering this question: (i) the history of the disease and the historical context in which the vaccine was developed; (ii) the type of vaccine used; (iii) the vaccination strategy and coverage; (iv) the disease surveillance after the introduction of generalized vaccination and (v) the surveillance for the causal agent of the disease.

  9. Circulation and Dissipation on Hot Jupiters

    CERN Document Server

    Li, Jason

    2010-01-01

    Many global circulation models predict supersonic zonal winds and large vertical shears in the atmospheres of short-period jovian exoplanets. Using linear analysis and nonlinear local simulations, we investigate hydrodynamic dissipation mechanisms to balance the thermal acceleration of these winds. The adiabatic Richardson criterion remains a good guide to linear stability, although thermal diffusion allows some modes to violate it at very long wavelengths and very low growth rates. Nonlinearly, wind speeds saturate at Mach numbers $\\approx 2$ and Richardson numbers $\\lesssim 1/4$ for a broad range of plausible diffusivities and forcing strengths. Turbulence and vertical mixing, though accompanied by weak shocks, dominate the dissipation, which appears to be the outcome of a recurrent Kelvin-Helmholtz instability. An explicit shear viscosity, as well as thermal diffusivity, is added to ZEUS to capture dissipation outside of shocks. The wind speed is not monotonic nor single valued for shear viscosities larger...

  10. Circulating amounts of osteoprotegerin and RANK ligand

    DEFF Research Database (Denmark)

    Abrahamsen, Bo; Hjelmborg, Jacob Vb; Kostenuik, Paul;

    2005-01-01

    was 1.04 +/- 0.11 g/cm2. Serum levels of OPG and RANKL were measured by ELISA (Biomedica, Vienna, Austria). Thisregister covers twins born in Denmark since 1870. Heritability and environmental influence was assessed using a maximum-likelihood model for genetic pleiotropy. RESULTS: RANKL levels showed...... only a weak relation to BMD in healthy women. Phenotype correlations indicate that the genes that contribute to twin similarity for BMD are not genes regulating serum levels of RANKL or OPG. The weak correlation with BMDappears to consist in shared environmental factors....... and cytokines. The influence of genetic factors on circulating amounts of OPG and RANKL is not known. BMD has been demonstrated to have a high heritability and there is evidence also that bone turnover and bone loss rates are controlled at least in part by genetic factors. OBJECTIVE: Assessing the genetic...

  11. Circulating Tumor Cells in Prostate Cancer

    Energy Technology Data Exchange (ETDEWEB)

    Hu, Brian [Institute of Urology, University of Southern California, 1441 Eastlake Avenue, Suite 7416, Los Angeles, CA 90033 (United States); Rochefort, Holly [Department of Surgery, University of Southern California, 1520 San Pablo Street, HCT 4300, Los Angeles, CA 90033 (United States); Goldkorn, Amir, E-mail: agoldkor@usc.edu [Department of Internal Medicine and Norris Comprehensive Cancer Center, University of Southern California Keck School of Medicine, 1441 Eastlake Avenue, Suite 3440, Los Angeles, CA 90033 (United States)

    2013-12-04

    Circulating tumor cells (CTCs) can provide a non-invasive, repeatable snapshot of an individual patient’s tumor. In prostate cancer, CTC enumeration has been extensively studied and validated as a prognostic tool and has received FDA clearance for use in monitoring advanced disease. More recently, CTC analysis has been shifting from enumeration to more sophisticated molecular characterization of captured cells, which serve as a “liquid biopsy” of the tumor, reflecting molecular changes in an individual’s malignancy over time. Here we will review the main CTC studies in advanced and localized prostate cancer, highlighting the important gains as well as the challenges posed by various approaches, and their implications for advancing prostate cancer management.

  12. Boiling Heat Transfer in Circulating Fluidized Beds

    Institute of Scientific and Technical Information of China (English)

    张利斌; 李修伦

    2001-01-01

    A model is proposed to predict boiling heat transfer coefficient in a three-phase circulating fluidized bed (CFB), which is a new type of evaporation boiling means for enhancing heat transfer and preventing fouling. To verify the model, experiments are conducted in a stainless steel column with 39 mm ID and 2.0 m height, in which the heat transfer coefficient is measured for different superficial velocities, steam pressures, particle concentrations and materials of particle. As the steam pressure and particle concentrations increase, the heat transfer coefficient in the bed increases. The heat transfer coefficient increases with the liquid velocity but it exhibits a local minimum.The heat transfer coefficient is correlated with cluster renewed model and two-mechanism method. The prediction of the model is in good agreement with experimental data.

  13. Boiling Heat Transfer in Circulating Fluidized Beds

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    A model is proposed to predict boiling heat transfer coefficient in a three-phase circulating fluidized bed (CFB), which is a new type of evaporation boiling means for enhancing heat transfer and preventing fouling. To verify the model, experiments are conducted in a stainless steel column with 39mm ID and 2.0m height, in which the heat transfer coefficient is measured for different superficial velocities, steam pressures, particle concentrations and materials of particle. As the steam pressure and particle concentrations increase, the heat transfer coefficient in the bed increases. The heat transfer coefficient increases with the liquid velocity but it exhibits a local minimum. The heat transfer coefficient is correlated with cluster renewed model and two-mechanism method. The prediction of the model is in good agreement with experimental data.

  14. Circulating Tumor Cells in Prostate Cancer

    Directory of Open Access Journals (Sweden)

    Brian Hu

    2013-12-01

    Full Text Available Circulating tumor cells (CTCs can provide a non-invasive, repeatable snapshot of an individual patient’s tumor. In prostate cancer, CTC enumeration has been extensively studied and validated as a prognostic tool and has received FDA clearance for use in monitoring advanced disease. More recently, CTC analysis has been shifting from enumeration to more sophisticated molecular characterization of captured cells, which serve as a “liquid biopsy” of the tumor, reflecting molecular changes in an individual’s malignancy over time. Here we will review the main CTC studies in advanced and localized prostate cancer, highlighting the important gains as well as the challenges posed by various approaches, and their implications for advancing prostate cancer management.

  15. Circulating tumor cells: highlight on practical implications.

    Science.gov (United States)

    Gazzaniga, Paola; Raimondi, Cristina; Gradilone, Angela; Naso, Giuseppe; Cortesi, Enrico; Frati, Luigi

    2012-02-01

    Circulating tumor cells (CTCs) are cells of presumed epithelial origin, whose prognostic and predictive value in metastatic cancer patients has recently been demonstrated. To date, the count of CTCs through the CellSearch® system represents a valid approach for monitoring disease status in patients with metastatic colorectal, breast, and prostate cancer; in these cancer types, a rise in the CTC count at any time during treatment predicts a poor outcome. Nevertheless, the clinical utility of monitoring CTC counts remains controversial, and what to do when CTC counts rise during therapy still remains an unanswered question. In this report, we suggest how to integrate CTC counts with their molecular characterization to better translate biologic information obtained on CTCs into daily clinical practice.

  16. Subsurface Meridional Circulation in the Active Belts

    CERN Document Server

    Hernandez, I Gonzalez; Hill, F; Howe, R; Komm, R

    2008-01-01

    Temporal variations of the subsurface meridional flow with the solar cycle have been reported by several authors. The measurements are typically averaged over periods of time during which surface magnetic activity existed in the regions were the velocities are calculated. The present work examines the possible contamination of these measurements due to the extra velocity fields associated with active regions plus the uncertainties in the data obtained where strong magnetic fields are present. We perform a systematic analysis of more than five years of GONG data and compare meridional flows obtained by ring-diagram analysis before and after removing the areas of strong magnetic field. The overall trend of increased amplitude of the meridional flow towards solar minimum remains after removal of large areas associated with surface activity. We also find residual circulation toward the active belts that persist even after the removal of the surface magnetic activity, suggesting the existence of a global pattern o...

  17. Circulating Tumor Cells, Enumeration and Beyond

    Directory of Open Access Journals (Sweden)

    Jian-Mei Hou

    2010-06-01

    Full Text Available The detection and enumeration of circulating tumor cells (CTCs has shown significant clinical utility with respect to prognosis in breast, colorectal and prostate cancers. Emerging studies show that CTCs can provide pharmacodynamic information to aid therapy decision making. CTCs as a ‘virtual and real-time biopsy’ have clear potential to facilitate exploration of tumor biology, and in particular, the process of metastasis. The challenge of profiling CTC molecular characteristics and generating CTC signatures using current technologies is that they enrich rather than purify CTCs from whole blood; we face the problem of looking for the proverbial ‘needle in the haystack’. This review summarizes the current methods for CTC detection and enumeration, focuses on molecular characterization of CTCs, unveils some aspects of CTC heterogeneity, describes attempts to purify CTCs and scans the horizon for approaches leading to comprehensive dissection of CTC biology.

  18. Meridional circulation in the Sun and stars

    CERN Document Server

    Kitchatinov, L L

    2016-01-01

    Mean-field hydrodynamics advanced to clear explanations for the origin and properties of the global meridional flow in stellar convection zones. Qualitative arguments and analysis of basic equations both show that the meridional circulation is driven by non-conservative centrifugal and buoyancy forces and results from a slight disbalance between these two drivers. The deviations from the thermal wind balance are relatively large near the boundaries of convection zones. Accordingly, the meridional flow attains its largest velocities in the boundary layers and decreases inside the convection zone. This picture, however, is neither supported nor dismissed by the conflicting results of recent helioseismic soundings or 3D numerical experiments. The relevant physics of the differential temperature and its possible relation to the solar oblateness are briefly discussed.

  19. Circulating tumor cells: utopia or reality?

    Science.gov (United States)

    Conteduca, Vincenza; Zamarchi, Rita; Rossi, Elisabetta; Condelli, Valentina; Troiani, Laura; Aieta, Michele

    2013-09-01

    Circulating tumor cells (CTCs) could be considered a sign of tumor aggressiveness, but highly sensitive and specific methods of CTC detection are necessary owing to the rarity and heterogeneity of CTCs in peripheral blood. This review summarizes recent studies on tumor biology, with particular attention to the metastatic cascade, and the molecular characterization and clinical significance of CTCs. Recent technological approaches to enrich and detect these cells and challenges of CTCs for individualized cancer treatment are also discussed. This review also provides an insight into the positive and negative features of the future potential applications of CTC detection, which sometimes remains still a 'utopia', but its actual utility remains among the fastest growing research fields in oncology.

  20. NUCLA Circulating Atmospheric Fluidized Bed Demonstration Project

    Energy Technology Data Exchange (ETDEWEB)

    Keith, Raymond E.; Heller, Thomas J.; Bush, Stuart A.

    1991-01-01

    This Annual Report on Colorado-Ute Electric Association's NUCLA Circulating Fluidized Bed (CFB) Demonstration Program covers the period from February 1987 through December 1988. The outline for presentation in this report includes a summary of unit operations along with individual sections covering progress in study plan areas that commenced during this reporting period. These include cold-mode shakedown and calibration, plant commercial performance statistics, unit start-up (cold), coal and limestone preparation and handling, ash handling system performance and operating experience, tubular air heater, baghouse operation and performance, materials monitoring, and reliability monitoring. During this reporting period, the coal-mode shakedown and calibration plan was completed. (VC)

  1. Fragment Length of Circulating Tumor DNA.

    Directory of Open Access Journals (Sweden)

    Hunter R Underhill

    2016-07-01

    Full Text Available Malignant tumors shed DNA into the circulation. The transient half-life of circulating tumor DNA (ctDNA may afford the opportunity to diagnose, monitor recurrence, and evaluate response to therapy solely through a non-invasive blood draw. However, detecting ctDNA against the normally occurring background of cell-free DNA derived from healthy cells has proven challenging, particularly in non-metastatic solid tumors. In this study, distinct differences in fragment length size between ctDNAs and normal cell-free DNA are defined. Human ctDNA in rat plasma derived from human glioblastoma multiforme stem-like cells in the rat brain and human hepatocellular carcinoma in the rat flank were found to have a shorter principal fragment length than the background rat cell-free DNA (134-144 bp vs. 167 bp, respectively. Subsequently, a similar shift in the fragment length of ctDNA in humans with melanoma and lung cancer was identified compared to healthy controls. Comparison of fragment lengths from cell-free DNA between a melanoma patient and healthy controls found that the BRAF V600E mutant allele occurred more commonly at a shorter fragment length than the fragment length of the wild-type allele (132-145 bp vs. 165 bp, respectively. Moreover, size-selecting for shorter cell-free DNA fragment lengths substantially increased the EGFR T790M mutant allele frequency in human lung cancer. These findings provide compelling evidence that experimental or bioinformatic isolation of a specific subset of fragment lengths from cell-free DNA may improve detection of ctDNA.

  2. Fragment Length of Circulating Tumor DNA.

    Science.gov (United States)

    Underhill, Hunter R; Kitzman, Jacob O; Hellwig, Sabine; Welker, Noah C; Daza, Riza; Baker, Daniel N; Gligorich, Keith M; Rostomily, Robert C; Bronner, Mary P; Shendure, Jay

    2016-07-01

    Malignant tumors shed DNA into the circulation. The transient half-life of circulating tumor DNA (ctDNA) may afford the opportunity to diagnose, monitor recurrence, and evaluate response to therapy solely through a non-invasive blood draw. However, detecting ctDNA against the normally occurring background of cell-free DNA derived from healthy cells has proven challenging, particularly in non-metastatic solid tumors. In this study, distinct differences in fragment length size between ctDNAs and normal cell-free DNA are defined. Human ctDNA in rat plasma derived from human glioblastoma multiforme stem-like cells in the rat brain and human hepatocellular carcinoma in the rat flank were found to have a shorter principal fragment length than the background rat cell-free DNA (134-144 bp vs. 167 bp, respectively). Subsequently, a similar shift in the fragment length of ctDNA in humans with melanoma and lung cancer was identified compared to healthy controls. Comparison of fragment lengths from cell-free DNA between a melanoma patient and healthy controls found that the BRAF V600E mutant allele occurred more commonly at a shorter fragment length than the fragment length of the wild-type allele (132-145 bp vs. 165 bp, respectively). Moreover, size-selecting for shorter cell-free DNA fragment lengths substantially increased the EGFR T790M mutant allele frequency in human lung cancer. These findings provide compelling evidence that experimental or bioinformatic isolation of a specific subset of fragment lengths from cell-free DNA may improve detection of ctDNA.

  3. Circulating Biomarker Panels in Alzheimer's Disease.

    Science.gov (United States)

    Zafari, Sachli; Backes, Christina; Meese, Eckart; Keller, Andreas

    2015-01-01

    The early diagnosis of diseases frequently represents an important unmet clinical need supporting in-time treatment of pathologies. This also applies to neurodegenerative diseases such as Alzheimer's disease (AD), the most common form of dementia, estimated to affect millions of individuals worldwide. The respective diagnostic and prognostic markers, especially for the preclinical stages of AD, are expected to improve patients' outcome significantly. In the last decades, many approaches to detecting AD have been developed, including markers to discover changes in amyloid-β levels [from cerebrospinal fluid (CSF) or using positron emission tomography] or other brain imaging technologies such as structural magnetic resonance imaging (MRI), functional-connectivity MRI or task-related functional MRI. A major challenge is the detection of AD using minimally or even noninvasive biomarkers from body fluids such as plasma or serum. Circulating biomarker candidates based on mRNAs or proteins measured from blood cells, plasma or serum have been proposed for various pathologies including AD. As for other diseases, there is a tendency to use marker signatures obtained by high-throughput approaches, which allow the generation of profiles of hundreds to thousands of biomarkers simultaneously [microarrays, mass spectrometry or next-generation sequencing (NGS)]. Beyond mRNAs and proteins, recent approaches have measured small noncoding RNA (so-called microRNA) profiles in AD patients' blood samples using NGS or array-based technologies. Generally, the development of marker panels is in its early stages and requires further, substantial clinical validation. In this review, we provide an overview of different circulating AD biomarkers, starting with a brief summary of CSF markers and focusing on novel biomarker signatures such as small noncoding RNA profiles.

  4. 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

  5. Circulating Tumor Cells Versus Circulating Tumor DNA in Colorectal Cancer: Pros and Cons.

    Science.gov (United States)

    Tan, Carlyn Rose C; Zhou, Lanlan; El-Deiry, Wafik S

    2016-06-01

    Circulating tumor cells (CTCs) and circulating tumor DNA (ctDNA) are emerging noninvasive multifunctional biomarkers in liquid biopsy allowing for early diagnosis, accurate prognosis, therapeutic target selection, spatiotemporal monitoring of metastasis, as well as monitoring response and resistance to treatment. CTCs and ctDNA are released from different tumor types at different stages and contribute complementary information for clinical decision. Although big strides have been taken in technology development for detection, isolation and characterization of CTCs and sensitive and specific detection of ctDNA, CTC-, and ctDNA-based liquid biopsies may not be widely adopted for routine cancer patient care until the suitability, accuracy, and reliability of these tests are validated and more standardized protocols are corroborated in large, independent, prospectively designed trials. This review covers CTC- and ctDNA-related technologies and their application in colorectal cancer. The promise of CTC-and ctDNA-based liquid biopsies is envisioned.

  6. 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.

  7. 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.

  8. 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...

  9. 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.)

  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. Circulating Tumor Cell and Cell-free Circulating Tumor DNA in Lung Cancer.

    Science.gov (United States)

    Nurwidya, Fariz; Zaini, Jamal; Putra, Andika Chandra; Andarini, Sita; Hudoyo, Achmad; Syahruddin, Elisna; Yunus, Faisal

    2016-09-01

    Circulating tumor cells (CTCs) are tumor cells that are separated from the primary site or metastatic lesion and disseminate in blood circulation. CTCs are considered to be part of the long process of cancer metastasis. As a 'liquid biopsy', CTC molecular examination and investigation of single cancer cells create an important opportunity for providing an understanding of cancer biology and the process of metastasis. In the last decade, we have seen dramatic development in defining the role of CTCs in lung cancer in terms of diagnosis, genomic alteration determination, treatment response and, finally, prognosis prediction. The aims of this review are to understand the basic biology and to review methods of detection of CTCs that apply to the various types of solid tumor. Furthermore, we explored clinical applications, including treatment monitoring to anticipate therapy resistance as well as biomarker analysis, in the context of lung cancer. We also explored the potential use of cell-free circulating tumor DNA (ctDNA) in the genomic alteration analysis of lung cancer.

  12. Response of the South Atlantic circulation to an abrupt collapse of the Atlantic meridional overturning circulation

    Energy Technology Data Exchange (ETDEWEB)

    Laurian, Audine [University of Hawai' i at Manoa, International Pacific Research Center, School of Ocean and Earth Science and Technology, Honolulu, HI (United States); Drijfhout, Sybren S. [Royal Netherlands Meteorological Institute, De Bilt (Netherlands)

    2011-08-15

    The South Atlantic response to a collapse of the North Atlantic meridional overturning circulation (AMOC) is investigated in the ECHAM5/MPI-OM climate model. A reduced Agulhas leakage (about 3.1 Sv; 1 Sv = 10{sup 6} m{sup 3} s{sup -1}) is found to be associated with a weaker Southern Hemisphere (SH) supergyre and Indonesian throughflow. These changes are due to reduced wind stress curl over the SH supergyre, associated with a weaker Hadley circulation and a weaker SH subtropical jet. The northward cross-equatorial transport of thermocline and intermediate waters is much more strongly reduced than Agulhas leakage in relation with an AMOC collapse. A cross-equatorial gyre develops due to an anomalous wind stress curl over the tropics that results from the anomalous sea surface temperature gradient associated with reduced ocean heat transport. This cross-equatorial gyre completely blocks the transport of thermocline waters from the South to the North Atlantic. The waters originating from Agulhas leakage flow somewhat deeper and most of it recirculates in the South Atlantic subtropical gyre, leading to a gyre intensification. This intensification is consistent with the anomalous surface cooling over the South Atlantic. Most changes in South Atlantic circulation due to global warming, featuring a reduced AMOC, are qualitatively similar to the response to an AMOC collapse, but smaller in amplitude. However, the increased northward cross-equatorial transport of intermediate water relative to thermocline water is a strong fingerprint of an AMOC collapse. (orig.)

  13. Tablets: A Survey of Circulation Policies at Academic Libraries

    Science.gov (United States)

    Derr, Janice; Tolppanen, Bradley P.

    2015-01-01

    This article presents the results of a Web-based survey regarding the circulation of tablets in academic libraries. The survey, which was completed by 61 respondents, identifies the most common circulation policies and procedures used. These results will help other academic institutions develop their own policy or update existing ones. Areas of…

  14. Exercise limitation in patients with Fontan circulation : A review

    NARCIS (Netherlands)

    Takken, Tim; Tacken, Marieke H. P.; Blank, A. Christian; Hulzebos, Erik H.; Strengers, Jan L. M.; Helders, Paul J. M.

    2007-01-01

    The aim of the current literature study was to perform a literature review of the factors contributing to exercise limitation and physiological response to exercise in patients with Fontan circulation. In patients with Fontan circulation, peak oxygen uptake ranged from about 14.4 to 32.3 ml/min/kg,

  15. Impact of interocean exchange on the Atlantic overturning circulation

    NARCIS (Netherlands)

    Weijer, W.

    2001-01-01

    The awareness that human activity could change climate has greatly raised public and scientific interest in climate. One issue of present-day climate research is the stability of the thermohaline circulation. This overturning circulation, popularly known as the `conveyor belt', redistributes w

  16. Abrupt climate change and thermohaline circulation: Mechanisms and predictability

    OpenAIRE

    J. Marotzke

    2000-01-01

    The ocean's thermohaline circulation has long been recognized as potentially unstable and has consequently been invoked as a potential cause of abrupt climate change on all timescales of decades and longer. However, fundamental aspects of thermohaline circulation changes remain poorly understood.

  17. Abrupt climate change and thermohaline circulation: mechanisms and predictability.

    Science.gov (United States)

    Marotzke, J

    2000-02-15

    The ocean's thermohaline circulation has long been recognized as potentially unstable and has consequently been invoked as a potential cause of abrupt climate change on all timescales of decades and longer. However, fundamental aspects of thermohaline circulation changes remain poorly understood.

  18. Circulating osteogenic cells: implications for injury, repair, and regeneration

    DEFF Research Database (Denmark)

    Pignolo, Robert J; Kassem, Moustapha

    2011-01-01

    The aim of this review is to provide a critical reading of recent literature pertaining to the presence of circulating, fluid-phase osteoblastic cells and their possible contribution to bone formation. We have termed this group of cells collectively as circulating osteogenic precursor (COP) cells...

  19. Consortial Book Circulation Patterns: The OCLC-OhioLINK Study

    Science.gov (United States)

    O'Neill, Edward T.; Gammon, Julia A.

    2014-01-01

    The OhioLINK consortium and OCLC Research collected and analyzed circulation data for libraries within the consortium. The study, which examines the circulation of 28,475,701 items from more than 100 academic libraries, is the largest and most diverse compilation of academic usage data for books ever collected. The authors outline the study…

  20. Unique Protein Signature of Circulating Microparticles in Systemic Lupus Erythematosus

    DEFF Research Database (Denmark)

    Østergaard, Ole; Nielsen, Christoffer; Iversen, Line V

    2013-01-01

    To characterize the unique qualities of proteins associated with circulating subcellular material in systemic lupus erythematosus (SLE) patients compared with healthy controls and patients with other chronic autoimmune diseases.......To characterize the unique qualities of proteins associated with circulating subcellular material in systemic lupus erythematosus (SLE) patients compared with healthy controls and patients with other chronic autoimmune diseases....

  1. 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

  2. CellTracks cytometer for detection of circulating tumor cells

    NARCIS (Netherlands)

    Tibbe, A.G.J.; Kooi, van der A.; Groot, de M.R.; Vermes, I.

    2003-01-01

    Introduction: In patients with carcinomas, tumor cells are shed into the circulation. The number of the circulating tumor cells is low and technology is needed that has sufficient sensitivity and specificity to enumerate and characterize these cells. The CellTracks system was developed to provide an

  3. Transient Characteristics of Residual Meridional Circulation during Stratospheric Sudden Warming

    Institute of Scientific and Technical Information of China (English)

    DENG Shumei; CHEN Yuejuan; HUANG Yong; LUO Tao; BI Yun

    2011-01-01

    The residual meridional circulation derived from the transformed Eulerian-mean thermodynamic equation and continuity equation can be separated into two parts, the slowly varying diabatic circulation and the transient circulation, as demonstrated by others. We calculated and composite-analyzed the transient and diabatic circulation for 14 stratospheric sudden warming (SSW) events from 1979-2002 by using the daily ECMWF reanalysis data. Specifically, the transient residual meridional circulation was calculated both with and without inclusion of the eddy heat transport term in the transformed Eulerian-mean thermodynamic equation to investigate the importance of the eddy heat transport term. The results showed that calculations of transient residual meridional circulation present rapid variations during SSWs, with or without inclusion of the eddy heat transport term. Although the patterns of transient residual meridional circulation with the eddy heat transport term were similar to that without the eddy heat transport term during SSW, the magnitudes in the upper stratosphere and high-latitude regions differed. As for the diabatic circulation, its daily variations were small during SSW events, and its patterns were in agreement with its monthly average.

  4. Transient Characteristics of Residual Meridional Circulation during Stratospheric Sudden Warming

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    The residual meridional circulation derived from the transformed Eulerian-mean thermodynamic equation and continuity equation can be separated into two parts,the slowly varying diabatic circulation and the transient circulation,as demonstrated by others.We calculated and composite-analyzed the transient and diabatic circulation for 14 stratospheric sudden warming(SSW) events from 1979-2002 by using the daily ECMWF reanalysis data.Specifically,the transient residual meridional circulation was calculated both with and without inclusion of the eddy heat transport term in the transformed Eulerian-mean thermodynamic equation to investigate the importance of the eddy heat transport term.The results showed that calculations of transient residual meridional circulation present rapid variations during SSWs,with or without inclusion of the eddy heat transport term.Although the patterns of transient residual meridional circulation with the eddy heat transport term were similar to that without the eddy heat transport term during SSW,the magnitudes in the upper stratosphere and high-latitude regions differed.As for the diabatic circulation,its daily variations were small during SSW events,and its patterns were in agreement with its monthly average.

  5. Circulation Price Elasticity in the Daily Newspaper Industry.

    Science.gov (United States)

    Grotta, Gerald L.; Taylor, Michael Lee

    Pricing of subscriptions and single copies has historically been arbitrary. Evidence indicates that the newspaper industry has tended to overestimate the elasticity of demand for newspaper circulation. This study analyzed price changes, circulation changes, and population changes for all daily newspapers in the United States between 1970 and 1975.…

  6. Circulating Immune Complexes among Diabetic Children

    Directory of Open Access Journals (Sweden)

    George Nicoloff

    2004-01-01

    Full Text Available Insulin dependent diabetes mellitus (IDDM is an autoimmune disease associated with the presence of different types of autoantibodies. The presence of these antibodies and the corresponding antigens in the circulation leads to the formation of circulating immune complexes (CIC. CIC are known to persist in the blood for long periods of time. Such CIC following deposition in the small blood vessels have the potential to lead to microangiopathy with debilitating clinical consequences. The aim of our pilot study was to investigate whether a correlation exists between CIC and the development of microvascular complications in diabetic children. Isolation of a new glycoprotein complement inhibition factor (CIF from the parasitic plant Cuscuta europea seed, which appears to bind specifically to complement component C3 has provided an unique tool for the measurement of immune complexes by means of ELISA-type techniques (CIF-ELISA. We studied the levels of CIC (IgG, IgM and IgA in 58 diabetic children (mean age 12.28±4.04 years, diabetes duration 5.3±3.7 years, 29 of them had vascular complications (group 1 and the other 29 were without vascular complications (group 2. As controls, we studied sera samples from 21 healthy children (mean age 13.54±4.03 years. Sera from the diabetic patients showed statistically significant higher levels of CIC IgG ( p=0.03 than sera from the control group. In sera from group 1 values of CIC IgG showed statistically significant higher levels than controls (0.720±0.31 vs. 0.46±0.045; p=0.011 Sera from 59% of the patients were positive for CIC IgG, 36% for CIC IgM and 9% for CIC IgA. Among 26 patients with microalbuminuria, sera from 17/26 (65% were positive for CIC IgG, 8/26 (31% for CIC IgM and 2/26 (8% for CIC IgA. CIC IgG correlated with HbA1c (r=0.51; p=0.005 and microalbuminuria (r=0.42, p=0.033. CIC IgA correlated with age (r=0.44, p=0.03. CIC IgM correlated with the duration of diabetes (r=0.63, p=0.02. These

  7. CIRCULATING MOVING BED COMBUSTION PROOF OF CONCEPT

    Energy Technology Data Exchange (ETDEWEB)

    Jukkola, Glen

    2010-06-30

    Circulating Moving Bed (CMB) combustion technology has its roots in traditional circulating fluidized bed technology and involves a novel method of solid fuel combustion and heat transfer. CMB technology represents a step change in improved performance and cost relative to conventional PC and FBC boilers. The CMB heat exchanger preheats the energy cycle working fluid, steam or air, to the high temperature levels required in systems for advanced power generation. Unique features of the CMB are the reduction of the heat transfer surfaces by about 60% as a result of the enhanced heat transfer rates, flexibility of operation, and about 30% lower cost over existing technology. The CMB Phase I project ran from July 2001 through March 2003. Its objective was to continue development of the CMB technology with a series of proof of concept tests. The tests were conducted at a scale that provided design data for scale up to a demonstration plant. These objectives were met by conducting a series of experiments in ALSTOM Power’s Multi-use Test Facility (MTF). The MTF was modified to operate under CMB conditions of commercial interest. The objective of the tests were to evaluate gas-to-solids heat transfer in the upper furnace, assess agglomeration in the high temperature CMB bubbling bed, and evaluate solids-to-tube heat transfer in the moving bed heat exchanger. The Phase I program results showed that there are still some significant technical uncertainties that needed to be resolved before the technology can be confidently scaled up for a successful demonstration plant design. Work remained in three primary areas: • scale up of gas to solid heat transfer • high temperature finned surface design • the overall requirements of mechanical and process design. The CMB Phase II workscope built upon the results of Phase I and specifically addressed the remaining technical uncertainties. It included a scaled MTF heat transfer test to provide the necessary data to scale up gas

  8. Compressed Sensing for Thoracic MRI with Partial Random Circulant Matrices

    Directory of Open Access Journals (Sweden)

    Hideaki Haneishi

    2012-03-01

    Full Text Available The use of Circulant matrix as the sensing matrix in compressed sensing (CS scheme has recently been proposed to overcome the limitation of random or partial Fourier matrices. Aside from reducing computational complexity, the use of circulant matrix for MR image offers the feasibility in hardware implementations. This paper presents the simulation of compressed sensing for thoracic MR imaging with circulant matrix as the sensing matrix. The comparisons of reconstruction of three different type MR images using circulant matrix are investigated in term of number of samples, number of iteration and signal to noise ratio (SNR. The simulation results showed that Circulant Matrix works efficiently for encoding the MR image of respiratory organ, especially for smooth and sparse image in spatial domain.

  9. The role of the thermohaline circulation in abrupt climate change.

    Science.gov (United States)

    Clark, Peter U; Pisias, Nicklas G; Stocker, Thomas F; Weaver, Andrew J

    2002-02-21

    The possibility of a reduced Atlantic thermohaline circulation in response to increases in greenhouse-gas concentrations has been demonstrated in a number of simulations with general circulation models of the coupled ocean-atmosphere system. But it remains difficult to assess the likelihood of future changes in the thermohaline circulation, mainly owing to poorly constrained model parameterizations and uncertainties in the response of the climate system to greenhouse warming. Analyses of past abrupt climate changes help to solve these problems. Data and models both suggest that abrupt climate change during the last glaciation originated through changes in the Atlantic thermohaline circulation in response to small changes in the hydrological cycle. Atmospheric and oceanic responses to these changes were then transmitted globally through a number of feedbacks. The palaeoclimate data and the model results also indicate that the stability of the thermohaline circulation depends on the mean climate state.

  10. Circulating CXCL16 in Diabetic Kidney Disease

    Directory of Open Access Journals (Sweden)

    Usama Elewa

    2016-09-01

    Full Text Available Background/Aims: Chronic kidney disease and, specifically, diabetic kidney disease, is among the fastest increasing causes of death worldwide. A better understanding of the factors contributing to the high mortality may help design novel monitoring and therapeutic approaches. CXCL16 is both a cholesterol receptor and a chemokine with a potential role in vascular injury and inflammation. We aimed at identifying predictors of circulating CXCL16 levels in diabetic patients with chronic kidney disease. Methods: We have now studied plasma CXCL16 in 134 European patients with diabetic kidney disease with estimated glomerular filtration rate (eGFR categories G1-G4 and albuminuria categories A1-A3, in order to identify factors influencing plasma CXCL16 in this population. Results: Plasma CXCL16 levels were 4.0±0.9 ng/ml. Plasma CXCL16 increased with increasing eGFR category from G1 to G4 (that is, with decreasing eGFR values and with increasing albuminuria category. Plasma CXCL16 was higher in patients with prior cardiovascular disease (4.33±1.03 vs 3.88±0.86 ng/ml; p=0.013. In multivariate analysis, eGFR and serum albumin had an independent and significant negative correlation with plasma CXCL16. Conclusion: In diabetic kidney disease patients, GFR and serum albumin independently predicted plasma CXCL16 levels.

  11. Circulating microRNAs in Cardiovascular Diseases.

    Science.gov (United States)

    Orlicka-Płocka, Marta; Gurda, Dorota; Fedoruk-Wyszomirska, Agnieszka; Smolarek, Iwona; Wyszko, Eliza

    2016-01-01

    Cardiovascular Diseases (CD) are currently one of the most common causes of death. Because heart related deaths occur on such an enormous scale this phenomenon is referred to as an epidemic. Chronic and acute injury of the heart could be an effect of cardiac remodeling, which is a result of molecular, cellular and interstitial changes, influenced by hemodynamic load or neurohormonal activation (Cohn et al., 2000). These small deviations in cardiac activity and morphology may lead to an enormous negative effect. Despite a significant progress, knowledge of standard risk factors for cardiovascular diseases has become less and less effective, which is why predicting and seeking an appropriate treatment is very challenging. As a result, there is a growing interest in finding new markers of the CD. MicroRNAs (miRNAs), are short, non-coding RNAs responsible for regulation of gene expression at the post-transcriptional level. Among them that have the greatest potential are microRNA molecules that circulate in the blood plasma or serum, that are related to direct activation of signaling pathways, implicated in the aging process and thus for the development of cardiovascular disease. This paper is a summary of the current state of knowledge on miRNAs, their biogenesis and potential role as biomarkers to diagnose heart disease.

  12. Circulation and Dissipation on Hot Jupiters

    Science.gov (United States)

    Li, J.; Goodman, J.

    2010-12-01

    Many global circulation models predict supersonic zonal winds and large vertical shears in the atmospheres of short-period Jovian exoplanets. Using linear analysis and nonlinear local simulations, we investigate hydrodynamic dissipation mechanisms to balance the thermal acceleration of these winds. The adiabatic Richardson criterion remains a good guide to linear stability, although thermal diffusion allows some modes to violate it at very long wavelengths and very low growth rates. Nonlinearly, wind speeds saturate at Mach numbers ≈2 and Richardson numbers lsim1/4 for a broad range of plausible diffusivities and forcing strengths. Turbulence and vertical mixing, though accompanied by weak shocks, dominate the dissipation, which appears to be the outcome of a recurrent Kelvin-Helmholtz instability. An explicit shear viscosity, as well as thermal diffusivity, is added to ZEUS to capture dissipation outside of shocks. The wind speed is neither monotonic nor single valued for a range of shear viscosities larger than about 10-3 of the sound speed times the pressure scale height. Coarsening the numerical resolution can also increase the speed. Hence global simulations that are incapable of representing vertical turbulence and shocks, either because of reduced physics or because of limited resolution, may overestimate wind speeds. We recommend that such simulations include artificial dissipation terms to control the Mach and Richardson numbers and to capture mechanical dissipation as heat.

  13. Global warming and thermohaline circulation stability.

    Science.gov (United States)

    Wood, Richard A; Vellinga, Michael; Thorpe, Robert

    2003-09-15

    The Atlantic thermohaline circulation (THC) plays an important role in global climate. Theoretical and palaeoclimatic evidence points to the possibility of rapid changes in the strength of the THC, including a possible quasi-permanent shutdown. The climatic impacts of such a shutdown would be severe, including a cooling throughout the Northern Hemisphere, which in some regions is greater in magnitude than the changes expected from global warming in the next 50 years. Other climatic impacts would likely include a severe alteration of rainfall patterns in the tropics, the Indian subcontinent and Europe. Modelling the future behaviour of the THC focuses on two key questions. (i) Is a gradual weakening of the THC likely in response to global warming, and if so by how much? (ii) Are there thresholds beyond which rapid or irreversible changes in the THC are likely? Most projections of the response of the THC to increasing concentrations of greenhouse gases suggest a gradual weakening over the twenty-first century. However, there is a wide variation between different models over the size of the weakening. Rapid or irreversible THC shutdown is considered a low-probability (but high-impact) outcome; however, some climate models of intermediate complexity do show the possibility of such events. The question of the future of the THC is beset with conceptual, modelling and observational uncertainties, but some current and planned projects show promise to make substantial progress in tackling these uncertainties in future.

  14. Isolation of Circulating Tumor Cells by Dielectrophoresis

    Energy Technology Data Exchange (ETDEWEB)

    Gascoyne, Peter R. C., E-mail: pgascoyn@mdanderson.org [Department of Imaging Physics Research, The University of Texas M.D. Anderson Cancer Center Unit 951, 1515 Holcombe Boulevard, Houston, TX 77030 (United States); Shim, Sangjo [Department of Imaging Physics Research, The University of Texas M.D. Anderson Cancer Center Unit 951, 1515 Holcombe Boulevard, Houston, TX 77030 (United States); Department of Biomedical Engineering, The University of Texas at Austin, 1 University Station, C0800, Austin, TX 78712 (United States); Present address: Micro & Nanotechnology Laboratory, University of Illinois at Urbana-Champaign, Urbana, 208 North Wright Street, Urbana, IL 61801 (United States)

    2014-03-12

    Dielectrophoresis (DEP) is an electrokinetic method that allows intrinsic dielectric properties of suspended cells to be exploited for discrimination and separation. It has emerged as a promising method for isolating circulation tumor cells (CTCs) from blood. DEP-isolation of CTCs is independent of cell surface markers. Furthermore, isolated CTCs are viable and can be maintained in culture, suggesting that DEP methods should be more generally applicable than antibody-based approaches. The aim of this article is to review and synthesize for both oncologists and biomedical engineers interested in CTC isolation the pertinent characteristics of DEP and CTCs. The aim is to promote an understanding of the factors involved in realizing DEP-based instruments having both sufficient discrimination and throughput to allow routine analysis of CTCs in clinical practice. The article brings together: (a) the principles of DEP; (b) the biological basis for the dielectric differences between CTCs and blood cells; (c) why such differences are expected to be present for all types of tumors; and (d) instrumentation requirements to process 10 mL blood specimens in less than 1 h to enable routine clinical analysis. The force equilibrium method of dielectrophoretic field-flow fractionation (DEP-FFF) is shown to offer higher discrimination and throughput than earlier DEP trapping methods and to be applicable to clinical studies.

  15. The Zonal Structure of the Hadley Circulation

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    A discussion of the mass transport of the Hadley circulation is presented, with regard to its longitudinal structure. Data from the NCEP/NCAR reanalysis data set for the period 1948-2005 is examined,focusing on the solsticial seasons of June-August and December-February. Quantitative estimates have been extracted from the data to observe connections between the zonal mean of the upper tropospheric north/south mass transports and their relationship to the driving factor of tropical precipitation (implying latent heat release) and subsidence in the subtropical high pressure belts. The longitudinal structure of this flow is then examined with regard to these three main variables. The poleward upper tropospheric transport has four (JJA) or three (DJF) main branches, which link regions of major precipitation with corresponding regions of large subsidence, and one (June, July, August) or two (December, January, February) reverse branches. This structure has remained stable over the past sixty years. Although the total upper tropospheric transport in each season is less than the total sinking transport in the target subtropical high pressure belt, this does not apply to the individual branches, the balance being made up by the upper tropospheric reverse transports. An analysis of correlations between all of these various components shows, however, that the complete picture is more complex, with some precipitation regions being linked to subsidence regions outside their own branch.

  16. Isolation of Circulating Tumor Cells by Dielectrophoresis

    Directory of Open Access Journals (Sweden)

    Peter R. C. Gascoyne

    2014-03-01

    Full Text Available Dielectrophoresis (DEP is an electrokinetic method that allows intrinsic dielectric properties of suspended cells to be exploited for discrimination and separation. It has emerged as a promising method for isolating circulation tumor cells (CTCs from blood. DEP-isolation of CTCs is independent of cell surface markers. Furthermore, isolated CTCs are viable and can be maintained in culture, suggesting that DEP methods should be more generally applicable than antibody-based approaches. The aim of this article is to review and synthesize for both oncologists and biomedical engineers interested in CTC isolation the pertinent characteristics of DEP and CTCs. The aim is to promote an understanding of the factors involved in realizing DEP-based instruments having both sufficient discrimination and throughput to allow routine analysis of CTCs in clinical practice. The article brings together: (a the principles of DEP; (b the biological basis for the dielectric differences between CTCs and blood cells; (c why such differences are expected to be present for all types of tumors; and (d instrumentation requirements to process 10 mL blood specimens in less than 1 h to enable routine clinical analysis. The force equilibrium method of dielectrophoretic field-flow fractionation (DEP-FFF is shown to offer higher discrimination and throughput than earlier DEP trapping methods and to be applicable to clinical studies.

  17. Circulating Humorous Antitobacco Videos on Social Media.

    Science.gov (United States)

    Lee, Moon J; Chen, Fannin

    2017-03-01

    We investigated whether exposure to same humorous antitobacco videos via different types of social media platforms and contexts (health vs. humor) influences individual's health risk perceptions, attitudes, and behavioral intents. An experiment with a 2 (social media types: YouTube and Facebook) × 2 (message contexts: health-focused and humor-focused contexts) factorial design was conducted. It was found that those who watched the humorous antitobacco videos on Facebook in the health-context exhibited a higher level of risk perception of smoking, less positive attitude toward smokers, and a higher level of intention to avoid smoking in the future than the participants who viewed the same videos on YouTube in the health-context or on Facebook in the humor-context. These findings provide useful practical guidelines in using social media for health communication/promotion. Humorous health promotion messages are best circulated on social networking sites such as Facebook accompanied by others' support for the given health topic (i.e., in health-contexts). Practical/theoretical implications and limitations of the study were further discussed in this article.

  18. High performance millimeter-wave microstrip circulators and isolators

    Science.gov (United States)

    Shih, Ming; Pan, J. J.

    1990-01-01

    Millimeter wave systems, phased array antennas, and high performance components all require wideband circulators (and isolators) to perform diplexing and switching, to improve isolation and Voltage Standing Wave Ratio (VSWR), and to construct IMPATT diode reflection amplifiers. Presently, most of the millimeter-wave circulators and isolators are available in the configurations of waveguide or stripline, both of which suffer from the shortcomings of bulky size/weight, narrow bandwidth, and poor compatibility with monolithic millimeter-wave integrated circuits (MMIC). MMW microstrip circulators/isolators can eliminate or improve these shortcomings. Stub-tuned microstrip circulator configuration were developed utilizing the electromagnetic fields perturbation technique, the adhesion problems of microstrip metallization on new ferrite substrate were overcome, the fabrication, assembly, packaging techniques were improved, and then successfully designed, fabricated a Ka band circulator which has isolation and return loss of greater than 16dB, insertion loss less than 0.7dB. To assess the steady and reliable performance of the circulator, a temperature cycling test was done over the range of -20 to +50 C for 3 continuous cycles and found no significant impact or variation of circulator performance.

  19. On affine connections in a Riemannian manifold with a circulant metric and two circulant affinor structures

    CERN Document Server

    Dokuzova, Iva

    2010-01-01

    In the present paper it is considered a class V of 3-dimensional Riemannian manifolds M with a metric g and two affinor tensors q and S. It is defined another metric \\bar{g} in M. The local coordinates of all these tensors are circulant matrices. It is found: 1)\\ a relation between curvature tensors R and \\bar{R} of g and \\bar{g}, respectively; 2)\\ an identity of the curvature tensor R of g in the case when the curvature tensor \\bar{R} vanishes; 3)\\ a relation between the sectional curvature of a 2-section of the type \\{x, qx\\} and the scalar curvature of M.

  20. 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.

  1. The Role of Eddy-Tansport in the Thermohaline Circulation

    Energy Technology Data Exchange (ETDEWEB)

    Dr. Paola Cessi

    2011-11-17

    Several research themes were developed during the course of this project. (1) Low-frequency oceanic varibility; (2) The role of eddies in the Antarctic Circumpolar Current (ACC) region; (3) Deep stratification and the overturning circulation. The key findings were as follows: (1) The stratification below the main thermocline (at about 500m) is determined in the circumpolar region and then communicated to the enclosed portions of the oceans through the overturning circulation. (2) An Atlantic pole-to-pole overturning circulation can be maintained with very small interior mixing as long as surface buoyancy values are shared between the northern North Atlantic and the ACC region.

  2. Ocean circulation: its effects on seasonal sea-ice simulations.

    Science.gov (United States)

    Hibler, W D; Bryan, K

    1984-05-04

    A diagnostic ice-ocean model of the Arctic, Greenland, and Norwegian seas is constructed and used to examine the role of ocean circulation in seasonal sea-ice simulations. The model includes lateral ice motion and three-dimensional ocean circulation. The ocean portion of the model is weakly forced by observed temperature and salinity data. Simulation results show that including modeled ocean circulation in seasonal sea-ice simulations substantially improves the predicted ice drift and ice margin location. Simulations that do not include lateral ocean movment predict a much less realistic ice edge.

  3. Parametric study on a natural circulation cooled U-battery

    Energy Technology Data Exchange (ETDEWEB)

    De Zwaan, Sieuwert; Kloosterman, Jan Leen [Delft University of Technology, Delft (Netherlands); Van Uitert, Gert [The Hague (Netherlands)

    2008-07-01

    A feasibility study has been performed on a natural circulation cooled small nuclear reactor with a molten salt or tin as a coolant. This reactor is called the U-Battery. The study included neutronics calculations to obtain the minimum dimensions required for a critical system during burnup, the calculation of coolant temperature and core temperature reactivity coefficients, and an investigation of the thermal hydraulics to asses the possibilities for natural circulation cooling. For every coolant, core designs are feasible within the dimensions imposed and with natural circulation of the coolant. (authors)

  4. 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.

  5. 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.

  6. Experimental Study on an On-Line Measurement of High Temperature Circulating Ash Flux in a Circulating Fluidized Bed Boiler

    Institute of Scientific and Technical Information of China (English)

    Lu Xiaofeng; Li Yourong

    2001-01-01

    A new kind of measuring method that may be used to measure high temperature circulating solid particles flux in a circulating fluidized bed boiler is studied in this paper. The measuring method is founded on the principle of thermal equilibrium. A series of cold tests and hot tests were carried to optimize the structure and collocation of water-cooling tubes and showed that the method had the advantage of simple, accurate, reliable and good applicability for on-line usage in a circulating fluidized bed boiler.

  7. Diagnostic technologies for circulating tumour cells and exosomes.

    Science.gov (United States)

    Shao, Huilin; Chung, Jaehoon; Issadore, David

    2015-11-24

    Circulating tumour cells (CTCs) and exosomes are promising circulating biomarkers. They exist in easily accessible blood and carry large diversity of molecular information. As such, they can be easily and repeatedly obtained for minimally invasive cancer diagnosis and monitoring. Because of their intrinsic differences in counts, size and molecular contents, CTCs and exosomes pose unique sets of technical challenges for clinical translation-CTCs are rare whereas exosomes are small. Novel technologies are underway to overcome these specific challenges to fully harness the clinical potential of these circulating biomarkers. Herein, we will overview the characteristics of CTCs and exosomes as valuable circulating biomarkers and their associated technical challenges for clinical adaptation. Specifically, we will describe emerging technologies that have been developed to address these technical obstacles and the unique clinical opportunities enabled by technological innovations.

  8. Study on Circulation and Management of Rural Land Use Right

    Institute of Scientific and Technical Information of China (English)

    Wanjiang WANG

    2015-01-01

    Currently,agriculture and rural economy have entered a new development stage. According to market demands and comparative advantages of regional resources,strategic adjustment of agricultural structure and realizing transformation from traditional agriculture to modern agriculture have become primary tasks. Land is the essential element of agricultural production,making innovation upon rural land use system and establishing flexible and effective land circulation system concern efficiency and optimization of agricultural resource allocation and development of rural element market. With more and more farmers engaged in secondary and tertiary industries,land left by those farmers is circulated to those farmers willing to do farming. Rural land circulation is inevitable trend of economic and social development,but it is a progressive process. To realize smooth rural land circulation,there must be standardized system.

  9. Circulation and geostrophic transport in the Bay of Bengal

    Digital Repository Service at National Institute of Oceanography (India)

    Rao, D.P.; Murty, V.S.N.

    Utilising the hydrographic data collected during the early northeast monsoon of 1983 and southwest monsoon of 1984, the circulation of waters of the Bay of Bengal and the associated volume transport have been studied in the upper 1000 m...

  10. Circulating mesenchymal stem cells and their clinical implications

    Directory of Open Access Journals (Sweden)

    Liangliang Xu

    2014-01-01

    Full Text Available Circulating mesenchymal stem cells (MSCs is a new cell source for tissue regeneration and tissue engineering. The characteristics of circulating MSCs are similar to those of bone marrow-derived MSCs (BM-MSCs, but they exist at a very low level in healthy individuals. It has been demonstrated that MSCs are able to migrate to the sites of injury and that they have some distinct genetic profiles compared to BM-MSCs. The current review summaries the basic knowledge of circulating MSCs and their potential clinical applications, such as mobilizing the BM-MSCs into circulation for therapy. The application of MSCs to cure a broad spectrum of diseases is promising, such as spinal cord injury, cardiovascular repair, bone and cartilage repair. The current review also discusses the issues of using of allogeneic MSCs for clinical therapy.

  11. Fructose ingestion acutely stimulates circulating FGF21 levels in humans

    OpenAIRE

    Dushay, Jody R.; Toschi, Elena; Mitten, Emilie K.; Fisher, ffolliott M.; Herman, Mark A.; Maratos-Flier, Eleftheria

    2014-01-01

    Objective Fibroblast growth factor 21 (FGF21) is a hormone with pleiotropic metabolic activities which, in rodents, is robustly regulated by fasting and ketogenic diets. In contrast, similar dietary interventions have either no or minimal effects on circulating FGF21 in humans. Moreover, no intervention or dietary challenge has been shown to acutely stimulate circulating FGF21 in either humans or animals. Recent animal data suggest that the transcription factor Carbohydrate Responsive-Element...

  12. [Fetal circulation in normal pregnancy and in placental insufficiency].

    Science.gov (United States)

    Ivanov, B; Malinova, M

    2010-01-01

    The fetal circulation is different from the adult circulation. One of the quite common conditions that are challenging to the developing fetus is placental hypoxia. Regardless of its cause, placental vascular insufficiency is commonly assumed to be an important factor in the development of intrauterine growth retardation. Several mechanisms are involved in the fetal adaptation to the decompensation during hypoxemia. Doppler Ultrasound technologies can help to evaluate of the fetal wellbeing.

  13. Poleward Expansion of the Hadley Circulation in CMIP5 Simulations

    Institute of Scientific and Technical Information of China (English)

    HU Yongyun; TAO Lijun; LIU Jiping

    2013-01-01

    Observational analyses have demonstrated that the Hadley circulation has expanded poleward in recent decades.Important issues are what caused the widening of the Hadley circulation and whether the observed widening is related to anthropogenic forcing.In the present study,we use currently available simulations of the Coupled Model Intercomparison Project Phase-5 (CMIP5) to analyze changes in the width of the Hadley circulation.It is found that CMIP5 historical simulations with greenhouse gas (GHG) forcing generate a total widening of ~0.15°±0.06° in latitude (10 yr)-1 for the period 1979-2005,and the widening in CMIP5 historical simulations with all forcings is ~0.17° ± 0.06° per decade.Similar to that in CMIP3,the simulated poleward expansion in CMIP5 is much weaker than the observational reanalyses.In CMIP5 projection simulations for the 21st century,magnitudes of widening of the Hadley circulation increase with radiative forcing.For the extreme projected radiative forcing of RCP8.5,the total annual-mean widening of the Hadley circulation is ~ 0.27° ± 0.04° (10 yr)-1 in the 21st century.Although CMIP5 underestimates observed poleward expansion of the Hadley circulation,the results of this study suggest that the observed trends in the width of the Hadley circulation are caused by anthropogenic forcing and that increasing GHGs play an important role in the observed poleward expansion of the Hadley circulation,in addition to other forcings emphasized in previous studies.

  14. Flow boiling heat transfer in circulating fluidized bed

    Institute of Scientific and Technical Information of China (English)

    Xiaoguang REN; Jiangdong ZHENG; Sefiane KHELLII; Arumemi-Ikhide MICHAEL

    2009-01-01

    In order to enhance heat transfer and mitigate contamination in the boiling processes, a new type of vapor-liquid-solid (3-phase) circulating fluidized bed boil-ing system has been designed, combining a circulating fluidized bed with boiling heat transfer. Experimental results show an enhancement of the boiling curve. Flow visualization studies concerning flow hydrodynamics within the riser column are also conducted whose results are presented and discussed.

  15. Computation of the q -th roots of circulant matrices

    Directory of Open Access Journals (Sweden)

    Pakizeh Mohammadi Khanghah

    2014-05-01

    Full Text Available In this paper‎, ‎we investigate the reduced form of circulant matrices‎ ‎and we show that the problem of computing the $q$-th roots of a‎ ‎nonsingular circulant matrix $A$ can be reduced to that of computing‎ ‎the $q$-th roots of two half size matrices $B-C$ and $B+C$. 

  16. 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.)

  17. 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.

  18. Distance spectra and Distance energy of Integral Circulant Graphs

    CERN Document Server

    c, Aleksandar Ili\\'

    2011-01-01

    The distance energy of a graph $G$ is a recently developed energy-type invariant, defined as the sum of absolute values of the eigenvalues of the distance matrix of $G$. There was a vast research for the pairs and families of non-cospectral graphs having equal distance energy, and most of these constructions were based on the join of graphs. A graph is called circulant if it is Cayley graph on the circulant group, i.e. its adjacency matrix is circulant. A graph is called integral if all eigenvalues of its adjacency matrix are integers. Integral circulant graphs play an important role in modeling quantum spin networks supporting the perfect state transfer. In this paper, we characterize the distance spectra of integral circulant graphs and prove that these graphs have integral eigenvalues of distance matrix $D$. Furthermore, we calculate the distance spectra and distance energy of unitary Cayley graphs. In conclusion, we present two families of pairs $(G_1, G_2)$ of integral circulant graphs with equal distanc...

  19. Cooling Performance of Natural Circulation for a Research Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Park, Suki; Chun, J. H.; Yum, S. B. [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2015-10-15

    This paper deals with the core cooling performance by natural circulation during normal operation and a flow channel blockage event in an open tank-in-pool type research reactor. The cooling performance is predicted by using the RELAP5/ MOD3.3 code. The core decay heat is usually removed by natural circulation to the reactor pool water in open tank-in-pool type research reactors with the thermal power less than several megawatts. Therefore, these reactors have generally no active core cooling system against a loss of normal forced flow. In reactors with the thermal power less than around one megawatt, the reactor core can be cooled down by natural circulation even during normal full power operation. The cooling performance of natural circulation in an open tank-in-pool type research reactor has been investigated during the normal natural circulation and a flow channel blockage event. It is found that the maximum powers without void generation at the hot channel are around 1.16 MW and 820 kW, respectively, for the normal natural circulation and the flow channel blockage event.

  20. Minor effect of meltwater on the ocean circulation during deglaciation

    Directory of Open Access Journals (Sweden)

    G. Lohmann

    2012-08-01

    Full Text Available Decaying Northern Hemisphere ice sheets during deglaciation affect the high latitude hydrological balance in the North Atlantic and therefore the ocean circulation after the Last Glacial Maximum. Surprisingly, geological data suggest that meltwater fluxes of about 14–20 m sea-level equivalent flushed into the North Atlantic without significantly influencing the Atlantic meridional overturning circulation. Using a three-dimensional ocean circulation model coupled to an energy balance model of the atmosphere, we investigate the response of the ocean circulation to spatio-temporal variable deglacial freshwater discharges. Freshwater inputs are simulated by a three-dimensional thermo-mechanical ice sheet model of the Northern Hemisphere. In our experiments, we find a strong sensitivity of the ocean circulation when the deglacial meltwater is injected into the surface layers yielding a quasi shut-down. On the other hand, the parameterization of huge sub-glacial outbursts as so-called hyperpycnal flows are mimicked through bottom injections in ocean models leading to a reduced sensitivity of the overturning circulation against freshwater perturbations and providing a consistent representation of the deglacial climate evolution.

  1. An efficiency booster for energy conversion in natural circulation loops

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Dongqing, E-mail: wangdongqing@stu.xjtu.edu.cn [School of Nuclear Science and Technology, Xi’an Jiaotong University, Xi’an, Shaanxi 710049 (China); Beijing Computational Science Research Center, Beijing 100084 (China); Jiang, Jin, E-mail: jjiang@eng.uwo.ca [Department of Electrical and Computer Engineering, The University of Western Ontario, London, Ontario N6A 5B9 (Canada); Beijing Computational Science Research Center, Beijing 100084 (China)

    2016-08-01

    Highlights: • Low driving power conversion efficiency of natural circulation loops is proved. • The low conversion efficiency leads to low heat transfer capacity of such loops. • An efficiency booster is designed with turbine to increase the efficiency. • Performance of the proposed booster has been numerically simulated. • The booster drastically enhances heat transfer capacity of such loops. - Abstract: In this paper, the capacity of a natural circulation loop for transferring heat from a heat source to a heat sink has been analyzed. It is concluded that the capacity of the natural circulation loop depends on the conversion efficiency of the thermal energy from the heat source to the driving force for the circulation of the flow. The low conversion efficiency leading to weak driving force in such loops has been demonstrated analytically and validated through simulation results. This issue has resulted in a low heat transfer capacity in the circulation loop. To increase the heat transfer capacity, one has to improve this efficiency. To meet such a need, a novel efficiency booster has been developed in this paper. The booster essentially increases the flow driving force and hence significantly improves the overall heat transfer capacity. Design and analysis of this booster have been performed in detail. The performance has been examined through extensive computer simulations. It is concluded that the booster can indeed drastically improve the heat transfer capacity of the natural circulation loop.

  2. SOLID HOLDUP AND CIRCULATION RATE IN A LIQUID-SOLID CIRCULATING FLUIDIZED BED WITH VISCOUS LIQUID MEDIUM

    Directory of Open Access Journals (Sweden)

    N. Gnanasundaram

    2015-12-01

    Full Text Available Abstract Experiments were conducted in a liquid-solid circulating fluidized bed with different viscous liquids and particles to study the hydrodynamics, average solid hold up and solid circulation rate. The effects of operating parameters, i.e., primary liquid flow rate in the riser, auxiliary liquid flow rate, total liquid flow rate and viscosity of the liquid were studied for solids of different density and particle size. Results show that the circulating fluidization regime starts earlier for more viscous solutions because of the decrease in critical transitional velocity. The onset of solid holdup increases with an increase in liquid viscosity for sand and for glass beads. The solid circulation rate increases with an increase in total velocity and auxiliary velocity, and also increases with increasing viscosity.

  3. Electromagnetic circulation pump for corrosive gases; Pompe de circulation electromagnetique pour gaz corrosifs

    Energy Technology Data Exchange (ETDEWEB)

    Noe, P.; Delafosse, D.; Deletre, G. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1965-07-01

    In order to transport very corrosive products (fluorinated compounds) we have been led to develop a totally metallic circulation pump capable of operating at above room temperatures and with a molecular vacuum. We have aimed at maximum simplicity both in its conception and in its operation. The tests showed that the compression ratios produced, although not high are interesting (1.5 at a pressure of 100 torr) (see curve I). The flow-rate range is very wide: about one hundred ccs/atm/min. to 3000 ccs/atm/min. (see curves IV, V, VI). The desorption of this pump presents no difficulty if both the aspiration and the reject sides are pumped together. A hole of 2 mm diameter drilled in the piston makes it possible to desorb the space between the two segments. The price of this pump is not high: 1300 F, with the electrical cabinet. (authors) [French] En vue de vehiculer des produits tres corrosifs (composes fluores) nous avons ete amene a realiser une pompe de circulation entierement metallique, capable de fonctionner en temperature et sous vide moleculaire. Nous avons recherche la simplicite tant dans sa realisation que dans son fonctionnement. Les essais ont montre que les taux de compression fournis, sans etre eleves, sont interessants (1,5 a la pression de 100 torr) (voir courbe I). La gamme des debits est tres large: d'une centaine de cm{sup 3}/atm/mn a 3000 cm{sup 3}/atm/mn (voir courbes IV, V, VI). La desorption de cette pompe ne presente pas de difficulte en pompant a la fois cote aspiration et cote refoulement. Un percage de 2 mm de diametre dans le piston permet la desorption de l'espace entre les 2 segments. Le cout de cette pompe est peu eleve: 1300 F, coffret electrique compris. (auteurs)

  4. Atmospheric circulation classification comparison based on wildfires in Portugal

    Science.gov (United States)

    Pereira, M. G.; Trigo, R. M.

    2009-04-01

    Atmospheric circulation classifications are not a simple description of atmospheric states but a tool to understand and interpret the atmospheric processes and to model the relation between atmospheric circulation and surface climate and other related variables (Radan Huth et al., 2008). Classifications were initially developed with weather forecasting purposes, however with the progress in computer processing capability, new and more robust objective methods were developed and applied to large datasets prompting atmospheric circulation classification methods to one of the most important fields in synoptic and statistical climatology. Classification studies have been extensively used in climate change studies (e.g. reconstructed past climates, recent observed changes and future climates), in bioclimatological research (e.g. relating human mortality to climatic factors) and in a wide variety of synoptic climatological applications (e.g. comparison between datasets, air pollution, snow avalanches, wine quality, fish captures and forest fires). Likewise, atmospheric circulation classifications are important for the study of the role of weather in wildfire occurrence in Portugal because the daily synoptic variability is the most important driver of local weather conditions (Pereira et al., 2005). In particular, the objective classification scheme developed by Trigo and DaCamara (2000) to classify the atmospheric circulation affecting Portugal have proved to be quite useful in discriminating the occurrence and development of wildfires as well as the distribution over Portugal of surface climatic variables with impact in wildfire activity such as maximum and minimum temperature and precipitation. This work aims to present: (i) an overview the existing circulation classification for the Iberian Peninsula, and (ii) the results of a comparison study between these atmospheric circulation classifications based on its relation with wildfires and relevant meteorological

  5. DEFORMATION OF MOISTURE FLUX CIRCULATION SURROUNDING THE LANDFALL TYPHOON "BILIS"

    Institute of Scientific and Technical Information of China (English)

    RAN Ling-kun; YANG Wen-xia; HONG Yan-chao

    2009-01-01

    The deformation parameter (DP), which is defined as the product of shear deformation and stretching deformation of moisture flux circulation, is introduced. The tendency equation of DP is derived in pressure coordinates. Furthermore, DP is used to diagnose the deformation character of moisture flux circulation in the periphery of Bilis. The analysis showed that before Bilis landed, DP presented eight abnormal areas, which distributed alternately and closely encircled the low-pressure center. This indicated that the moisture flux circulation in the periphery of Bilis rotated counterclockwise and stretched longitudinally and latitudinally to deform. After Bilis landed, DP weakened gradually and its regular pattern of horizontal distribution loosened. The shear and stretching deformations of moisture flux circulation surrounding Bilis weakened after the typhoon landed. The deformation of moisture flux circulation in the periphery of Bilis mainly appeared in the middle-lower troposphere. There existed 1/2 phase difference between the shear and stretching deformations in the vertical-latitudinal cross section and a π/4 phase difference between them on the horizontal plane. As Bilis landed and further moved inland of China, the intensities of DP, shear and stretching deformations decreased, meanwhile their vertical and horizontal structures became irregular. The chief dynamic factors responsible for the deformation of moisture flux circulation in the periphery of Bilis were the three terms associated with the three-dimensional advection transportation of DP, square difference between shear and stretching deformations coupling with Coriolis parameter, and horizontal gradient of geopotential height before Bilis landed. The last two dynamic factors impacted jointly on the deformation of moisture flux circulation after Bilis landed.

  6. Characterization of quantum circulant networks having perfect state transfer

    Science.gov (United States)

    Bašić, Milan

    2013-01-01

    In this paper we answer the question of when circulant quantum spin networks with nearest-neighbor couplings can give perfect state transfer. The network is described by a circulant graph G, which is characterized by its circulant adjacency matrix A. Formally, we say that there exists a perfect state transfer (PST) between vertices {a,bin V(G)} if | F( τ) ab | = 1, for some positive real number τ, where F( t) = exp(i At). Saxena et al. (Int J Quantum Inf 5:417-430, 2007) proved that | F( τ) aa | = 1 for some {ain V(G)} and {tauin {R}^+} if and only if all eigenvalues of G are integer (that is, the graph is integral). The integral circulant graph ICG n ( D) has the vertex set Z n = {0, 1, 2, . . . , n - 1} and vertices a and b are adjacent if {gcd(a-b,n)in D} , where {D subseteq {d : d mid n, 1 ≤ d < n}} . These graphs are highly symmetric and have important applications in chemical graph theory. We show that ICG n ( D) has PST if and only if {nin 4{N}} and {D=widetilde{D_3} \\cup D_2\\cup 2D_2\\cup 4D_2|cup {n/2^a}} , where {widetilde{D_3}={din D | n/din 8{N}}, D_2= {din D | n/din 8{N}+4}{setminus}{n/4}} and {ain{1,2}} . We have thus answered the question of complete characterization of perfect state transfer in integral circulant graphs raised in Angeles-Canul et al. (Quantum Inf Comput 10(3&4):0325-0342, 2010). Furthermore, we also calculate perfect quantum communication distance (distance between vertices where PST occurs) and describe the spectra of integral circulant graphs having PST. We conclude by giving a closed form expression calculating the number of integral circulant graphs of a given order having PST.

  7. A probabilistic method of calculating circulation-induced trends

    Science.gov (United States)

    Brox Nilsen, Irene; Stagge, James Howard; Merete Tallaksen, Lena

    2015-04-01

    The water cycle in Europe has changed substantially over the past three decades. Increasing runoff is observed during winter and at northern latitudes in particular. Spring and summer months, as well as southern latitudes, are facing drier conditions. To understand what is driving large-scale changes in runoff, we look into changes in precipitation and temperature and link these to changes in atmospheric circulation. Previous studies have used the method of trend ratios (Cahynová and Huth, 2009) to attribute precipitation and temperature trends to changes in the frequency of circulation types. A trend ratio is the ratio of hypothetical trend, i.e., the trend that would result due to changes in circulation type frequency only, to the observed trend. However, the method of trend ratios has two drawbacks. First, if the observed trend is small, division by a very low value results in a meaningless trend ratio and thus requires a cut-off value to keep the trend ratio within meaningful boundaries. Second, the method does not allow a comparison of the observed trend to the spread of possible outcomes, because the method of hypothetical trends is based on a deterministic model. We propose a new, more robust method for detecting the importance of circulation-induced changes in explaining the observed trends, which has the benefit of being a non-parametric statistical test that assesses the entire range of hypothetical trends. Instead of creating a hypothetical series by replacing the observation on a given day with the long-term climatic mean of a certain month and circulation type (as in the existing trend ratio method), the new approach replaces the observation on a given day with a random sample from the distribution of the variable for the given month and circulation type. The method introduces the possibility to assign a rejection rate, thus allowing statistical significance to be assessed. We apply the method on time series of precipitation and temperature from the

  8. Glacial ocean circulation and stratification explained by reduced atmospheric temperature

    Science.gov (United States)

    Jansen, Malte F.

    2017-01-01

    Earth’s climate has undergone dramatic shifts between glacial and interglacial time periods, with high-latitude temperature changes on the order of 5–10 °C. These climatic shifts have been associated with major rearrangements in the deep ocean circulation and stratification, which have likely played an important role in the observed atmospheric carbon dioxide swings by affecting the partitioning of carbon between the atmosphere and the ocean. The mechanisms by which the deep ocean circulation changed, however, are still unclear and represent a major challenge to our understanding of glacial climates. This study shows that various inferred changes in the deep ocean circulation and stratification between glacial and interglacial climates can be interpreted as a direct consequence of atmospheric temperature differences. Colder atmospheric temperatures lead to increased sea ice cover and formation rate around Antarctica. The associated enhanced brine rejection leads to a strongly increased deep ocean stratification, consistent with high abyssal salinities inferred for the last glacial maximum. The increased stratification goes together with a weakening and shoaling of the interhemispheric overturning circulation, again consistent with proxy evidence for the last glacial. The shallower interhemispheric overturning circulation makes room for slowly moving water of Antarctic origin, which explains the observed middepth radiocarbon age maximum and may play an important role in ocean carbon storage.

  9. Static slot testing of conventional lost circulation materials

    Energy Technology Data Exchange (ETDEWEB)

    Hinkebein, T.E.; Behr, V.L.; Wilde, S.L.

    1983-01-01

    A study of the utility of conventional lost circulation materials and testing methods was performed using a modified API slot tester. Five lost circulation materials were evaluated in 266 tests at both room temperature and temperature-aged conditions simulating expected geothermal environments. A large variation in the maximum pressure (or sealing pressure) the plug could withstand was attributed to nonrepeatability in plug strengths. Plugs were composed to multiple or single particle bridges, with the latter providing stronger, better sealing plugs. Seals occurred on the upstream surface of the slots in all cases. Sealing pressures generally decreased with increasing slot widths and decreasing solids concentration. When the slot width was less than the size of the largest rigid particle in the lost circulation slurry, sealing pressure was maximized. When the slot width was greater than three times the maximum rigid particle size, no significant sealing ability was observed with the conventional materials tested. Additionally, cellulosic lost circulation materials are severely degraded by temperature aging. Mud gellation provided no significant improvement in lost circulation material sealing ability.

  10. 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)

  11. Mixing and dissipation in a geostrophic buoyancy-driven circulation

    Science.gov (United States)

    Vreugdenhil, Catherine A.; Gayen, Bishakhdatta; Griffiths, Ross W.

    2016-08-01

    Turbulent mixing and energy dissipation have important roles in the global circulation but are not resolved by ocean models. We use direct numerical simulations of a geostrophic circulation, resolving turbulence and convection, to examine the rates of dissipation and mixing. As a starting point, we focus on circulation in a rotating rectangular basin forced by a surface temperature difference but no wind stress. Emphasis is on the geostrophic regime for the horizontal circulation, but also on the case of strong buoyancy forcing (large Rayleigh number), which implies a turbulent convective boundary layer. The computed results are consistent with existing scaling theory that predicts dynamics and heat transport dependent on the relative thicknesses of thermal and Ekman boundary layers, hence on the relative roles of buoyancy and rotation. Scaling theory is extended to describe the volume-integrated rate of mixing, which is proportional to heat transport and decreases with increasing rotation rate or decreasing temperature difference. In contrast, viscous dissipation depends crucially on whether the thermal boundary layer is laminar or turbulent, with no direct Coriolis effect on the turbulence unless rotation is extremely strong. For strong forcing, in the geostrophic regime, the mechanical energy input from buoyancy goes primarily into mixing rather than dissipation. For a buoyancy-driven circulation in a basin comparable to the North Atlantic we estimate that the total rate of mixing accounts for over 95% of the mechanical energy supply, implying that buoyancy is an efficient driver of mixing in the oceans.

  12. Self-biased circulators for high power applications

    Science.gov (United States)

    Sokolov, Alexander S.

    Self-biased circulators exploit the properties of high anisotropy magnetic field in hexagonal ferrites, thus allowing operation without biasing magnets and a significant size and weight reduction. Although first self-biased circulators were demonstrated more than 20 years ago, all the prototypes constructed so far are unsuitable for practical applications. An attempt to design a self-biased circulator from scratch was made. Novel exceptionally low dielectric loss and high heat conductivity ceramic materials were developed and innovative substrate synthesis techniques were employed. Low temperature cofiring of green body ferrite compacts and dielectric ceramic slurries were mastered, resulting in solid composite substrates. Original device design was developed. Key features (including wide coupling angles, wide microstriplines, thick substrate, and absence of impedance transformers) enable low insertion loss, broadband operation, high power handling, and compact size. Fabrication and testing of Ka band Y-junction self-biased circulator are reported herein. Furthermore, design approach and fabrication techniques developed here can be readily applied for the construction of X-band self-biased circulators, provided that suitable ferrite materials are available. Low temperature cofiring of ferrite and dielectric materials is especially beneficial for various RF and high-frequency applications. Multiple devices can be readily fabricated on a single wafer using conventional lithographic techniques, resulting in true microwave monolithic integrated circuit.

  13. Composite circulation index of weather extremes (the example for Poland

    Directory of Open Access Journals (Sweden)

    Zbigniew Ustrnul

    2013-10-01

    Full Text Available The paper describes the implementation of a composite circulation index of weather extremes (CIE. The new index informs about the synoptic conditions favoring the occurrence of extremes on a regional scale. It was evaluated for temperature and precipitation extremes for Poland. Daily homogenized data obtained from 14 weather stations, which cover most of the country, were used. The data used cover the 60-year period from 1951 to 2010. The index is based on relationships between extremes and mesoscale circulation conditions. The core material also included data describing circulation types for the study period. Three different calendars were used (Grosswetterlagen, by Lity?ski, by Nied?wied?. The conditional probability of the occurrence of extremes for particular types was calculated independently using partial indices (Partial Index of weather Extremes ? PIE. The higher the index values, the more favorable the synoptic situation for the occurrence of extremes. The results were grouped by describing the probability of temperature and precipitation extremes on the IPCC likelihood scale. Three thresholds corresponding to the frequency of an occurrence were identified via a seasonal approach. The CIE was validated using basic correlation coefficients as well as contingency tables based on feature-displacement criteria and Bayesian Probability Methods. The results confirmed the significance of atmospheric circulation in the formation of temperature and precipitation extremes in Poland. The CIE proved the relationship by trying to estimate the probability of temperature and precipitation extremes occurrence depending on the circulation type forecasted.

  14. Seasonal variability in the Central Mediterranean Sea circulation

    Directory of Open Access Journals (Sweden)

    R. Sorgente

    Full Text Available A high resolution eddy-resolving primitive equation numerical model, based on the Princeton Ocean Model (POM, is used to study the seasonal variability of the general circulation in the Central Mediterranean Sea. The model is run on a seasonal cycle, perpetual year simulation for five years, with nesting to the coarser resolution Ocean General Circulation Model (OGCM, covering the whole Mediterranean Sea. The model results are compared to the current knowledge on the hydrography and dynamics of the area, with a special focus on the annual cycle of the Modified Atlantic Water (MAW, on the circulation in the Sardinia Channel, the water exchange across the Strait of Sicily, and on the transition and fate of the Levantine Intermediate Water (LIW. The results show that the adopted coupling techniques between the two models give a proficient downscaling of the large-scale OGCM flow field into the regional scale model. The numerical solution is also used to highlight the seasonal characteristics of important dynamical features in the area, as well as to shed light on the scarcely known circulation regimes along the north African shelf and slope.

    Key words. Oceanography: general (numerical modelling; Oceanography: physical (currents; general circulation

  15. Circulation in the South China Sea in summer of 1998

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Based on the CTD and meteorological data obtained by R/V Xiangyanghong No.14 in the South China Sea (SCS) in the summer of 1998, both current velocity and volume transport are calculated by using a modified inverse model. Circulation in the SCS is analyzed by combining the calculated results with ADCP data. The following results are obtained. (i) The most important feature of the circulation in the northeastern SCS is that a branch of the Kuroshio intrudes into the SCS with a small volume transport. It flows anticyclonically through the Bashi Strait and towards the southwest off the Taiwan Island, and it does not intrude into the inner SCS. (ii) The northern SCS is dominated mainly by a cyclonic circulation system with two cold eddies. (iii) The central and southwestern SCSs are mainly occupied by anticyclonic circulation systems, including three anticyclonic and one stronger cyclonic eddies. (iv) In the southeastern SCS, there is a large scope of cyclonic circulation extending in the SW-NE direction. (v) There is a "multi-eddy phenomenon" in the SCS, and a larger eddy contains several small eddies. (vi) There is western intensifying of the currents and eddies in the SCS.

  16. Experimental study of two-phase natural circulation circuit

    Energy Technology Data Exchange (ETDEWEB)

    Lemos, Wanderley Freitas; Su, Jian, E-mail: wlemos@lasme.coppe.ufrj.br, E-mail: sujian@nuclear.ufrj.br [Coordenacao dos Programas de Pos-Graduacao em Engenharia (COPPE/UFRJ), Rio de Janeiro, RJ (Brazil). Programa de Engenharia Nuclear; Faccini, Jose Luiz Horacio, E-mail: faccini@ien.gov.br [Instituto de Engenharia Nuclear (IEN/CNEN-RJ), RIo de Janeiro, RJ (Brazil). Lab. de Termo-Hidraulica Experimental

    2012-07-01

    This paper reports an experimental study on the behavior of fluid flow in natural circulation under single-and two-phase flow conditions. The natural circulation circuit was designed based on concepts of similarity and scale in proportion to the actual operating conditions of a nuclear reactor. This test equipment has similar performance to the passive system for removal of residual heat presents in Advanced Pressurized Water Reactors (A PWR). The experiment was carried out by supplying water to primary and secondary circuits, as well as electrical power resistors installed inside the heater. Power controller has available to adjust the values for supply of electrical power resistors, in order to simulate conditions of decay of power from the nuclear reactor in steady state. Data acquisition system allows the measurement and control of the temperature at different points by means of thermocouples installed at several points along the circuit. The behavior of the phenomenon of natural circulation was monitored by a software with graphical interface, showing the evolution of temperature measurement points and the results stored in digital format spreadsheets. Besides, the natural circulation flow rate was measured by a flowmeter installed on the hot leg. A flow visualization technique was used the for identifying vertical flow regimes of two-phase natural circulation. Finally, the Reynolds Number was calculated for the establishment of a friction factor correlation dependent on the scale geometrical length, height and diameter of the pipe. (author)

  17. Multi-stage circulating fluidized bed syngas cooling

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Guohai; Vimalchand, Pannalal; Guan, Xiaofeng; Peng, WanWang

    2016-10-11

    A method and apparatus for cooling hot gas streams in the temperature range 800.degree. C. to 1600.degree. C. using multi-stage circulating fluid bed (CFB) coolers is disclosed. The invention relates to cooling the hot syngas from coal gasifiers in which the hot syngas entrains substances that foul, erode and corrode heat transfer surfaces upon contact in conventional coolers. The hot syngas is cooled by extracting and indirectly transferring heat to heat transfer surfaces with circulating inert solid particles in CFB syngas coolers. The CFB syngas coolers are staged to facilitate generation of steam at multiple conditions and hot boiler feed water that are necessary for power generation in an IGCC process. The multi-stage syngas cooler can include internally circulating fluid bed coolers, externally circulating fluid bed coolers and hybrid coolers that incorporate features of both internally and externally circulating fluid bed coolers. Higher process efficiencies can be realized as the invention can handle hot syngas from various types of gasifiers without the need for a less efficient precooling step.

  18. Predisposing factors in posterior circulation infarcts: a vascular morphological assessment

    Energy Technology Data Exchange (ETDEWEB)

    Coban, Goekcen; Cifci, Egemen; Yildirim, Erkan; Agildere, Ahmet Muhtesem [Baskent University Faculty of Medicine, Department of Radiology, Konya (Turkey)

    2015-05-01

    The aim of the study is to assess the effect of shape, diameter, elongation and deviation criteria of basilar artery (BA), convergence angle and diameter variations of vertebral arteries, and concurrent chronic diseases on posterior circulation infarcts. Between January 2010 and May 2013, 186 patients who underwent brain and diffusion magnetic resonance imaging (MRI) with suspected cerebrovascular accident and were diagnosed with posterior circulation infarct and 120 infarct negative control subjects were included in this case-control retrospective study. Vertebral artery (VA) and BA diameter, right (R) and left (L) VA angles at the level of bifurcation, and BA elongation-deviation, and shape of BA were assessed in a total of 306 subjects. Ischemic lesions in the posterior circulation were classified according to their anatomical location and vascular perfusion areas. No significant difference was noted between the control and patient groups with respect to BA diameter (p = 0.676). The most effective risk factors for posterior circulation infarcts were as follows: BA elongation of 2 or 3, BA transverse location of 2 or 3, increase in left VA angle, and history of hypertension, hypercholesterolemia, and diabetes mellitus. Our results suggest that prominent elongation and deviation, C and J shape of BA, and increased L VA angle may be the predictors of at-risk patients in posterior circulation infarcts. Reporting marked morphological BA and VA variations detected at routine brain MRI will aid in selection of patients. Timely detection and treatment of at-risk patients may be life-saving. (orig.)

  19. Derivation of multipotent progenitors from human circulating CD14+ monocytes.

    Science.gov (United States)

    Seta, Noriyuki; Kuwana, Masataka

    2010-07-01

    Circulating CD14(+) monocytes are originated from hematopoietic stem cells in the bone marrow and believed to be committed precursors for phagocytes, such as macrophages. Recently, we have reported a primitive cell population termed monocyte-derived multipotential cells (MOMCs), which has a fibroblast-like morphology in culture and a unique phenotype positive for CD14, CD45, CD34, and type I collagen. MOMCs are derived from circulating CD14(+) monocytes, but circulating precursors for MOMCs still remain undetermined. Comparative analysis of gene expression profiles of MOMCs and other monocyte-derived cells has revealed that embryonic stem cell markers, Nanog and Oct-4, are specifically expressed by MOMCs. In vitro generation of MOMCs requires binding to fibronectin and exposure to soluble factors derived from activated platelets. MOMCs contain progenitors with capacity to differentiate into a variety of nonphagocytes, including bone, cartilage, fat, skeletal and cardiac muscle, neuron, and endothelium, indicating that circulating monocytes are more multipotent than previously thought. In addition, MOMCs are capable of promoting ex vivo expansion of human hematopoietic progenitor cells through direct cell-to-cell contact and secretion of a variety of hematopoietic growth factors. These findings obtained from the research on MOMCs indicate that CD14(+) monocytes in circulation are involved in a variety of physiologic functions other than innate and acquired immune responses, such as repair and regeneration of the damaged tissue.

  20. Stability of Thermohaline circulation with respect to fresh water release

    CERN Document Server

    Patwardhan, Ajay

    2008-01-01

    The relatively warm climate found in the North- Western Europe is due to the gulf stream that circulates warm saline water from southern latitudes to Europe. In North Atlantic ocean the stream gives out a large amount of heat, cools down and sinks to the bottom to complete the Thermohaline circulation. There is considerable debate on the stability of the stream to inputs of fresh water from the melting ice in Greenland and Arctic. The circulation, being switched off, will have massive impact on the climate of Europe. Intergovernmental panel on climate change (IPCC) has warned of this danger in its recent report. Our aim is to model the Thermohaline circulation at the point where it sinks in the North-Atlantic. We create a two dimensional discrete map modeling the salinity gradient and vertical velocity of the stream. We look for how a perturbation in the form of fresh water release can destabilise the circulation by pushing the velocity below a certain threshold.

  1. Numerical analysis of seawater circulation in carbonate platforms: II. The dynamic interaction between geothermal and brine reflux circulation

    Science.gov (United States)

    Jones, G.D.; Whitaker, F.F.; Smart, P.L.; Sanford, W.E.

    2004-01-01

    Density-driven seawater circulation may occur in carbonate platforms due to geothermal heating and / or reflux of water of elevated salinity. In geothermal circulation lateral contrasts in temperature between seawater and platform groundwaters warmed by the geothermal heat flux result in upward convective flow, with colder seawater drawn into the platform at depth. With reflux circulation, platform-top waters concentrated by evaporation flow downward, displacing less dense underlying groundwaters. We have used a variable density groundwater flow model to examine the pattern, magnitude and interaction of these two different circulation mechanisms, for mesosaline platform-top waters (50???) and brines concentrated up to saturation with respect to gypsum (150???) and halite (246???). Geothermal circulation, most active around the platform margin, becomes restricted and eventually shut-off by reflux of brines from the platform interior towards the margin. The persistence of geothermal circulation is dependent on the rate of brine reflux, which is proportional to the concentration of platform-top brines and also critically dependent on the magnitude and distribution of permeability. Low permeability evaporites can severely restrict reflux whereas high permeability units in hydraulic continuity enhance brine transport. Reduction in permeability with depth and anisotropy of permeability (kv < < kh) focuses flow laterally in the shallow subsurface (<1 km), resulting in a horizontally elongated brine plume. Aquifer porosity and dispersivity are relatively minor controls on reflux. Platform brines can entrain surficial seawater when brine generating conditions cease but the platform-top remains submerged, a variant of reflux we term "latent reflux". Brines concentrated up to gypsum saturation have relatively long residence times of at least 100 times the duration of the reflux event. They thus represent a long-term control on post-reflux groundwater circulation, and

  2. Norms and Spread of the Fibonacci and Lucas RSFMLR Circulant Matrices

    Directory of Open Access Journals (Sweden)

    Wenai Xu

    2015-01-01

    Full Text Available Circulant type matrices have played an important role in networks engineering. In this paper, firstly, some bounds for the norms and spread of Fibonacci row skew first-minus-last right (RSFMLR circulant matrices and Lucas row skew first-minus-last right (RSFMLR circulant matrices are given. Furthermore, the spectral norm of Hadamard product of a Fibonacci RSFMLR circulant matrix and a Lucas RSFMLR circulant matrix is obtained. Finally, the Frobenius norm of Kronecker product of a Fibonacci RSFMLR circulant matrix and a Lucas RSFMLR circulant matrix is presented.

  3. The Problems in Circulation Channel of Dujiangyan Kiwi Fruit and the Countermeasures

    Institute of Scientific and Technical Information of China (English)

    2012-01-01

    Based on the overview of researches on circulation channel of agricultural products,this article presents the status quo of circulation channel of Dujiangyan kiwi fruit,including the production and circulation pattern of Dujiangyan kiwi fruit. Then it analyzes the problems in the current circulation channel of Dujiangyan kiwi fruit as follows: first,the long circulation channel leads to inefficient circulation and high costs; second,the deep processing capacity is poor,and the added value of fruits is low; third,the application of cold chain logistics technology is insufficient; fourth, blocked information circulation makes the cooperative relations between the subjects in channel fragile. Finally corresponding countermeasures and recommendations are put forward as follows: shortening circulation channel and improving circulation efficiency; improving deep processing capacity,and increasing added value of fruits; strengthening the use of cold chain logistics technology and equipments; establishing rational interest distribution mechanism,and consolidating cooperation between the circulation subjects.

  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. Ocean Circulation and Dynamics on the West Antarctic Peninsula Continental Shelf

    Science.gov (United States)

    2007-09-01

    Upwelling-favorable winds force roughly the opposite circulation. The cyclonic circulation on the trough helps advect blobs of salty, warm and...roughly the opposite circulation. The cyclonic circulation on the trough helps advect blobs of salty, warm and nutrient-rich water across the shelf...of Warm Events .................... 116 4.5 Circulation Associated with the Warm Events ................ 117 4.5.1 Eddies Advected Pass a Mooring

  6. In Defense of Sparse Tracking: Circulant Sparse Tracker

    KAUST Repository

    Zhang, Tianzhu

    2016-12-13

    Sparse representation has been introduced to visual tracking by finding the best target candidate with minimal reconstruction error within the particle filter framework. However, most sparse representation based trackers have high computational cost, less than promising tracking performance, and limited feature representation. To deal with the above issues, we propose a novel circulant sparse tracker (CST), which exploits circulant target templates. Because of the circulant structure property, CST has the following advantages: (1) It can refine and reduce particles using circular shifts of target templates. (2) The optimization can be efficiently solved entirely in the Fourier domain. (3) High dimensional features can be embedded into CST to significantly improve tracking performance without sacrificing much computation time. Both qualitative and quantitative evaluations on challenging benchmark sequences demonstrate that CST performs better than all other sparse trackers and favorably against state-of-the-art methods.

  7. QUASI-SYSTEMATIC BLOCK-CIRCULANT LDPC CODES

    Institute of Scientific and Technical Information of China (English)

    Xu Ying; Wei Guo

    2008-01-01

    A class of Quasi-Systematic Block-Circulant Low-Density Parity-Check (QSBC-LDPC) codes is proposed. Block-circulant LDPC codes have been studied a lot recently,because the simple structures of their parity-check matrices are very helpful to reduce the implementation complexities.QSBC-LDPC codes are special block-circulant LDPC codes with quasi-systematic parity-check ma-trices. The memories for encoders of QSBC-LDPC codes are limited,and the encoding process can be carried out in a simple recursive way with low complexities. Researches show that the QSBC-LDPC codes can provide remarkable performances with low encoding complexities.

  8. Quantum optical circulator controlled by a single chirally coupled atom

    Science.gov (United States)

    Scheucher, Michael; Hilico, Adèle; Will, Elisa; Volz, Jürgen; Rauschenbeutel, Arno

    2016-12-01

    Integrated nonreciprocal optical components, which have an inherent asymmetry between their forward and backward propagation direction, are key for routing signals in photonic circuits. Here, we demonstrate a fiber-integrated quantum optical circulator operated by a single atom. Its nonreciprocal behavior arises from the chiral interaction between the atom and the transversally confined light. We demonstrate that the internal quantum state of the atom controls the operation direction of the circulator and that it features a strongly nonlinear response at the single-photon level. This enables, for example, photon number–dependent routing and novel quantum simulation protocols. Furthermore, such a circulator can in principle be prepared in a coherent superposition of its operational states and may become a key element for quantum information processing in scalable integrated optical circuits.

  9. The Atlantic Meridional Overturning Circulation and Abrupt Climate Change

    Science.gov (United States)

    Lynch-Stieglitz, Jean

    2017-01-01

    Abrupt changes in climate have occurred in many locations around the globe over the last glacial cycle, with pronounced temperature swings on timescales of decades or less in the North Atlantic. The global pattern of these changes suggests that they reflect variability in the Atlantic meridional overturning circulation (AMOC). This review examines the evidence from ocean sediments for ocean circulation change over these abrupt events. The evidence for changes in the strength and structure of the AMOC associated with the Younger Dryas and many of the Heinrich events is strong. Although it has been difficult to directly document changes in the AMOC over the relatively short Dansgaard-Oeschger events, there is recent evidence supporting AMOC changes over most of these oscillations as well. The lack of direct evidence for circulation changes over the shortest events leaves open the possibility of other driving mechanisms for millennial-scale climate variability.

  10. 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...

  11. Ensemble meteorological reconstruction using circulation analogues of 1781–1785

    Directory of Open Access Journals (Sweden)

    P. Yiou

    2013-09-01

    Full Text Available This paper uses a method of atmospheric flow analogues to reconstruct an ensemble of atmospheric variables (namely sea-level pressure, surface temperature and wind speed between 1781 and 1785. The properties of this ensemble are investigated and tested against observations of temperature. The goal of the paper is to assess whether the atmospheric circulation during the Laki volcanic eruption (in 1783 and the subsequent winter were similar to the conditions that prevailed in the winter 2009/2010 and during spring 2010. We find that the three months following the Laki eruption in June 1783 barely have analogues in 2010. The cold winter of 1783/1784 yields circulation analogues in 2009/2010. Our analysis suggests that it is unlikely that the Laki eruption was responsible for the cold winter of 1783/1784, of the relatively short memory of the atmospheric circulation.

  12. Characteristics of oily sludge combustion in circulating fluidized beds.

    Science.gov (United States)

    Zhou, Lingsheng; Jiang, Xiumin; Liu, Jianguo

    2009-10-15

    Incineration of oily sludge in circulating fluidized beds may be an effective way for its management in some cases. The objective of the present paper is to investigate combustion characteristics of oily sludge, which would be helpful and useful for the design and simulation of a circulating fluidized bed. Firstly, the pyrolysis and combustion of oily sludge were studied through some thermal analyses, which included the thermogravimetric (TG) analysis and the differential thermal analytical (DTA) analysis. It was found that the combustion of oily sludge might be the combustion of its pyrolysis products. Secondly, an experiment for measuring of main components of the volatile from oily sludge pyrolysis was carried out. Some mathematic correlations about the compositions of volatile from oily sludge devolatilization were achieved from the experimental results. Finally, the combustion characteristics of oily sludge was studied in a lab-scale circulating fluidized bed, which could obtain some information about the location of release and combustion of the volatiles.

  13. Dynamics of collateral circulation in progressive asymptomatic carotid disease.

    Science.gov (United States)

    Moll, F L; Eikelboom, B C; Vermeulen, F E; van Lier, H J; Schulte, B P

    1986-03-01

    Inadequacy of collateral arterial flow is the major risk factor for hemispheric infarction in association with spontaneous occlusion of the ipsilateral carotid artery. This prospective study was designed to measure the adaptation of collateral cerebral circulation through the circle of Willis in patients in whom a unilateral carotid stenosis of hemodynamic consequence develops asymptomatically. The collateral cerebral potential is assessed by ocular pneumoplethysmography (OPG) during proximal common carotid artery compression, measuring the collateral ophthalmic artery pressure (COAP). During an average follow-up of almost 3 years (maximum more than 7 years), 45 patients showed asymptomatic development of a unilateral hemodynamically significant carotid stenosis according to OPG evidence. In these patients the mean index COAP/brachial artery pressure did not change on the side of stenosis progression (p greater than 0.05). The developed carotid stenosis had only reduced collateral circulation to the contralateral hemisphere. The risk of inadequate collateral cerebral circulation remained during progression of asymptomatic extracranial arterial obstructive disease.

  14. The complexity, function and applications of RNA in circulation

    Directory of Open Access Journals (Sweden)

    Alton eEtheridge

    2013-06-01

    Full Text Available Blood carries a wide array of biomolecules, including nutrients, hormones and molecules that are secreted by cells for specific biological functions. The recent finding of stable RNA of both endogenous and exogenous origin in the circulation raises a number of questions and opens a broad, new field: exploring the origins, functions and applications of these extracellular RNA molecules. These findings raise many important questions, including: what are the mechanisms of export and cellular uptake, what is the nature and source of their stability, what molecules do they interact with in the blood, and what are the possible biological functions of the circulating RNA. This review summarizes some key recent developments in circulating RNA research and discusses some of the open questions in the field.

  15. Evolution of oceanic circulation theory:From gyres to eddies*

    Institute of Scientific and Technical Information of China (English)

    HUANG Rui-xin

    2013-01-01

      Physical oceanography is now entering the eddy-resolving era. Eddies are commonly referred to the so-called mesoscale or submesoscale eddies;by definition, they have horizontal scales from 1 to 500 km and vertical scales from meters to hundreds of meters. In one word, the ocean is a turbulent environment; thus, eddy motions are one of the fundamental aspects of oceanic circulation. Studies of these eddies, including observations, theory, laboratory experiments, and parameterization in numerical models, will be the most productive research frontiers for the next 10 to 20 years. Although we have made great efforts to collect data about eddies in the ocean; thus far, we know very little about the three-dimensional structure of these eddies and their contributions to the oceanic general circulation and climate. Therefore, the most important breakthrough may come from observations and physical reasoning about the fundament aspects of eddy structure and their contributions to ocean circulation and climate.

  16. Three-dimensional decomposition method of global atmospheric circulation

    Institute of Scientific and Technical Information of China (English)

    LIU HaiTao; HU ShuJuan; XU Ming; CHOU JiFan

    2008-01-01

    By adopting the idea of three-dimensional Walker, Hadley and Rossby stream functions, the global atmospheric circulation can be considered as the sum of three stream functions from a global perspective. Therefore, a mathematical model of three-dimensional decomposition of global atmospheric circulation is proposed and the existence and uniqueness of the model are proved. Besides, the model includes a numerical method leading to no truncation error in the discrete three-dimensional grid points. Results also show that the three-dimensional stream functions exist and are unique for a given velocity field. The mathematical model shows the generalized form of three-dimensional stream functions equal to the velocity field in representing the features of atmospheric motion. Besides, the vertical velocity calculated through the model can represent the main characteristics of the vertical motion. In sum, the three-dimensional decomposition of atmospheric circulation is convenient for the further investigation of the features of global atmospheric motions.

  17. Circulation-strain sum rule in stochastic magnetohydrodynamics.

    Science.gov (United States)

    Moriconi, L; Nobre, F A S

    2002-03-01

    We study probability density functions (PDFs) of the circulation of velocity and magnetic fields in magnetohydrodynamics, computed for a circular contour within inertial range scales. The analysis is based on the instanton method as adapted to the Martin-Siggia-Rose field theory formalism. While in the viscous limit the expected Gaussian behavior of fluctuations is indeed verified, the case of vanishing viscosity is not suitable of a direct saddle-point treatment. To study the latter limit, we take into account fluctuations around quasistatic background fields, which allows us to derive a sum rule relating PDFs of the circulation observables and the rate of the strain tensor. A simple inspection of the sum rule definition leads straightforwardly to the algebraic decay rho(Gamma)-1/Gamma(2) at the circulation PDF tails.

  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. On the clique number of integral circulant graphs

    CERN Document Server

    Bašić, Milan

    2011-01-01

    The concept of gcd-graphs is introduced by Klotz and Sander, which arises as a generalization of unitary Cayley graphs. The gcd-graph $X_n (d_1,...,d_k)$ has vertices $0,1,...,n-1$, and two vertices $x$ and $y$ are adjacent iff $\\gcd(x-y,n)\\in D = \\{d_1,d_2,...,d_k\\}$. These graphs are exactly the same as circulant graphs with integral eigenvalues characterized by So. In this paper we deal with the clique number of integral circulant graphs and investigate the conjecture proposed in \\cite{klotz07} that clique number divides the number of vertices in the graph $X_n (D)$. We completely solve the problem of finding clique number for integral circulant graphs with exactly one and two divisors. For $k \\geqslant 3$, we construct a family of counterexamples and disprove the conjecture in this case.

  20. Integral circulant graphs of prime power order with maximal energy

    CERN Document Server

    Sander, Jürgen W; 10.1016/j.laa.2011.05.039

    2011-01-01

    The energy of a graph is the sum of the moduli of the eigenvalues of its adjacency matrix. We study the energy of integral circulant graphs, also called gcd graphs, which can be characterized by their vertex count n and a set D of divisors of n in such a way that they have vertex set Zn and edge set {{a, b} : a, b in Zn; gcd(a - b, n) in D}. Using tools from convex optimization, we study the maximal energy among all integral circulant graphs of prime power order ps and varying divisor sets D. Our main result states that this maximal energy approximately lies between s(p - 1)p^(s-1) and twice this value. We construct suitable divisor sets for which the energy lies in this interval. We also characterize hyperenergetic integral circulant graphs of prime power order and exhibit an interesting topological property of their divisor sets.

  1. Circulating DNA as Potential Biomarker for Cancer Individualized Therapy

    Institute of Scientific and Technical Information of China (English)

    Yu Shaorong; Liu Baorui; Lu Jianwei; Feng Jifeng

    2013-01-01

    Cancer individualized therapy often requires for gene mutation analysis of tumor tissue. However, tumor tissue is not always available in clinical practice, particularly from patients with refractory and recurrence disease. Even if patients have sufifcient tumor tissue for detection, as development of cancer, the gene status and drug sensitivity of tumor tissues could also change. Hence, screening mutations from primary tumor tissues becomes useless, it’s necessary to ifnd a surrogate tumor tissue for individualized gene screening. Circulating DNA is digested rapidly from blood, which could provide real-time information of the released fragment and make the real-time detection possible. Therefore, it’s expected that circulating DNA could be a potential tumor biomarker for cancer individualized therapy. This review focuses on the biology and clinical utility of circulating DNA mainly on gene mutation detection. Besides, its current status and possible direction in this research area is summarized and discussed objectively.

  2. Circulating Vitamin D and Risk of Epithelial Ovarian Cancer

    Directory of Open Access Journals (Sweden)

    Alan A. Arslan

    2009-01-01

    Full Text Available We conducted a nested case-control study within two prospective cohorts, the New York University Women's Health Study and the Northern Sweden Health and Disease Study, to examine the association between prediagnostic circulating levels of 25-hydroxy vitamin D (25(OHD and the risk of subsequent invasive epithelial ovarian cancer (EOC. The 25(OHD levels were measured in serum or plasma from 170 incident cases of EOC and 373 matched controls. Overall, circulating 25(OHD levels were not associated with the risk of EOC in combined cohort analysis: adjusted OR for the top tertile versus the reference tertile, 1.09 (95% CI, 0.59–2.01. In addition, there was no evidence of an interaction effect between VDR SNP genotype or haplotype and circulating 25(OHD levels in relation to ovarian cancer risk, although more complex gene-environment interactions may exist.

  3. 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.

  4. Dynamic sea level changes following changes in the thermohaline circulation

    CERN Document Server

    Levermann, A; Hofmann, M; Montoya, M; Rahmstorf, S; Levermann, Anders; Griesel, Alexa; Hofmann, Matthias; Montoya, Marisa; Rahmstorf, Stefan

    2004-01-01

    Using the coupled climate model CLIMBER-3a, we investigate changes in sea surface elevation due to a weakening of the thermohaline circulation (THC). In addition to a global sea level rise due to a warming of the deep sea, this leads to a regional dynamic sea level change which follows quasi-instantaneously any change in the ocean circulation. We show that the magnitude of this dynamic effect can locally reach up to ~1m, depending on the initial THC strength. In some regions the rate of change can be up to 20-25 mm/yr. The emerging patterns are discussed with respect to the oceanic circulation changes. Most prominent is a south-north gradient reflecting the changes in geostrophic surface currents. Our results suggest that an analysis of observed sea level change patterns could be useful for monitoring the THC strength.

  5. Keynes's Lost Distinction Between Industrial and Financial Circulation of Money

    DEFF Research Database (Denmark)

    Jespersen, Jesper

    2010-01-01

    's view on financial circulation. As a matter of fact, it is financial circulation which contributed significantly to the inflated asset bubble in the first place and to the credit crunch in the second round. Hence, bank lending, which creates means of payment, should be regulated and monitored closely......Although financial circulation is an important part of banks' balance sheets in the form of savings deposits, this is hardly discussed in monetary circuit theory. In this paper, we argue that monetary circuit theory would be more coherent if it were expanded to incorporate some aspects of Keynes....... In particular, banks should be divided into two categories: industrial or business banks, where deposits are used as means of payment (and covered by a State guarantee), and financial banks, where deposits carry an interest, but are not guaranteed by legal arrangement. This regulation would limit the amount...

  6. 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.

  7. NIHSS and acute complications after anterior and posterior circulation strokes

    Directory of Open Access Journals (Sweden)

    Godefroy O

    2012-02-01

    Full Text Available Mathieu Boone1, Jean-Marc Chillon2, Pierre-Yves Garcia1, Sandrine Canaple1, Chantal Lamy1, Olivier Godefroy1,3, Jean-Marc Bugnicourt1,2,31Department of Neurology, Amiens University Hospital, Amiens, France, 2INSERM ERI-12, and University of Picardie, 3Laboratory of Functional Neurosciences and Pathology (EA 4559, Amiens, FranceBackground: The purpose of this study was to determine whether the National Institutes of Health Stroke Scale (NIHSS score was associated with inhospital neurological and medical complications (NMC in patients with posterior circulation infarction.Methods: This retrospective study included all patients admitted to our stroke unit during a one-year period (n = 289. NMC included neurological deterioration (ie, worsening by 4 points or more of the NIHSS score during the hospital stay and all other medical complications based on what was recorded in the patients' charts.Results: Seventy-nine patients (27% experienced NMC. In posterior circulation infarction patients (n = 90, patients with NMC had a higher baseline NIHSS score (10.9 versus 2.2, P = 0.004 and a baseline NIHSS score >2 (78% versus 36%, P = 0.003. In stepwise logistic regression, an NIHSS score >2 (odds ratio: 8.2; 95% confidence interval: 1.64–41.0; P = 0.01 was associated with NMC. Similar results were observed for anterior circulation infarction patients but with a higher cutoff value for NIHSS score.Conclusion: In ischemic stroke patients, an increased baseline NIHSS score was associated with an increased risk of NMC. This association applied to anterior-circulation as well as posterior circulation stroke, although zero on the NIHSS for posterior circulation stroke does not mean the absence of NMC during hospitalization. The clinical significance of these findings requires further evaluation in larger prospective studies.Keywords: acute, stroke, rating scales, complications

  8. 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.

  9. The global ocean circulation on a retrograde rotating earth

    Directory of Open Access Journals (Sweden)

    V. Kamphuis

    2010-11-01

    Full Text Available To understand the three-dimensional ocean circulation patterns that have occurred in past continental geometries, it is crucial to study the role of the present-day continental geometry and surface (wind stress and buoyancy forcing on the present-day global ocean circulation. This circulation, often referred to as the Conveyor state, is characterized by an Atlantic Meridional Overturning Circulation (MOC with deep water formation at northern latitudes and the absence of such deep water formation in the North Pacific. This MOC asymmetry is often attributed to the difference in surface freshwater flux: the North Atlantic is a basin with net evaporation, while the North Pacific receives net precipitation. This issue is revisited in this paper by considering the global ocean circulation on a retrograde rotating earth, computing an equilibrium state of the coupled atmosphere-ocean-land surface-sea ice model CCSM3. The Atlantic-Pacific asymmetry in surface freshwater flux is indeed reversed but the ocean circulation pattern is not an Inverse Conveyor state (with deep water formation in the North Pacific as there is strong and highly variable deep water formation in the North Atlantic. Using a fully-implicit, global ocean-only model also the stability properties of the Atlantic MOC on a retrograde rotating earth are investigated, showing a similar regime of multiple equilibria as in the present-day case. These results demonstrate that the present-day asymmetry in surface freshwater flux is not a crucial factor for the Atlantic-Pacific asymmetry in the global MOC.

  10. On the symmetries of some classes of recursive circulant graphs

    Directory of Open Access Journals (Sweden)

    Seyed Morteza Mirafzal

    2014-03-01

    Full Text Available A recursive-circulant $G(n; d$ is defined to be acirculant graph with $n$ vertices and jumps of powers of $d$.$G(n; d$ is vertex-transitive, and has some strong hamiltonianproperties. $G(n; d$ has a recursive structure when $n = cd^m$,$1 leq c < d $ [10]. In this paper, we will find the automorphismgroup of some classes of recursive-circulant graphs. In particular, wewill find that the automorphism group of $G(2^m; 4$ is isomorphicwith the group $D_{2 cdot 2^m}$, the dihedral group of order $2^{m+1}

  11. Circulating micrornas as potential biomarkers of muscle atrophy

    Science.gov (United States)

    Wang, Fei

    2016-07-01

    Noninvasive biomarkers with diagnostic value and prognostic applications have long been desired to replace muscle biopsy for muscle atrophy patients. Growing evidence indicates that circulating microRNAs are biomarkers to assess pathophysiological status. Here, we show that the medium levels of six muscle-specific miRNAs (miR-1/23a/206/133/499/208b, also known as myomiRs) were all elevated in the medium of starved C2C12 cell (P atrophy patients, indicating that they might represent the degree of muscle atrophy. Collectively, our data indicated that circulating myomiRs could serve as promising biomarkers for muscle atrophy.

  12. Factors affecting the enterohepatic circulation of oral contraceptive steroids.

    Science.gov (United States)

    Orme, M L; Back, D J

    1990-12-01

    Oral contraceptive steroids may undergo enterohepatic circulation, but it is relevant for only estrogens, because these compounds can be directly conjugated in the liver. Animal studies show convincing evidence of the importance of the enterohepatic circulation, but studies in humans are much less convincing. The importance of the route and the rate of metabolism of ethinyl estradiol are reviewed. Some antibiotics have been reported anecdotally to reduce the efficacy of oral contraceptive steroids, but controlled studies have not confirmed this observation. Although gut flora are altered by oral antibiotics, the blood levels of ethinyl estradiol are not reduced, and one antibiotic at least (cotrimoxazole) enhances the activity of ethinyl estradiol.

  13. Topological phases and circulating states of Bose-Einstein condensates

    CERN Document Server

    Petrosyan, K G

    1999-01-01

    We show that the quantum topological effect predicted by Aharonov and Casher (AC effect) [Phys. Rev. Lett. 53, 319 (1984)] may be used to create circulating states of magnetically trapped atomic Bose-Einstein condensates (BEC). A simple experimental setup is suggested based on a multiply connected geometry such as a toroidal trap or a magnetic trap pinched by a blue-detuned laser. We give numerical estimates of such effects within the current atomic BEC experiments, and point out some interesting properties of the associated quantized circulating states.

  14. k-Diameter of Circulant Graph with Degree 3

    Institute of Scientific and Technical Information of China (English)

    ZHANG Xian-di; LI Man-li

    2005-01-01

    Parameters k-distance and k-diameter are extension of the distance and the diameter in graph theory. In this paper, the k-distance dk (x,y) between the any vertices x andy is first obtained in a connected circulant graph G with order n (n is even) and degree 3 by removing some vertices from the neighbour set of the x. Then, the k-diameters of the connected circulant graphs with order n and degree 3 are given by using the k-diameter dk (x, y).

  15. Dynamic sea level changes following changes in the thermohaline circulation

    OpenAIRE

    Levermann, Anders; Griesel, Alexa; Hofmann, Matthias; Montoya Redondo, María Luisa; Rahmstorf, Stefan

    2005-01-01

    Using the coupled climate model CLIMBER-3a, we investigate changes in sea surface elevation due to a weakening of the thermohaline circulation (THC). In addition to a global sea level rise due to a warming of the deep sea, this leads to a regional dynamic sea level change which follows quasi-instantaneously any change in the ocean circulation. We show that the magnitude of this dynamic effect can locally reach up to ~1m, depending on the initial THC strength. In some regions the rate of chang...

  16. 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.

  17. 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.``

  18. Extension of Goldstein's circulation function for optimal rotors with hub

    DEFF Research Database (Denmark)

    Okulov, Valery; Sørensen, Jens Nørkær; Shen, Wen Zhong

    2016-01-01

    The aerodynamic interaction or interference between rotor blades and hub body is usually very complicated, but some useful simplifications can be made by considering the hub with an infinite cylinder. Various attempts to find the optimum distribution of circulation by the lifting vortex lines...... method have been previously proposed to describe the blade interaction with the hub modeled by the infinite cylinder. In this case, the ideal distribution of bound circulation on the rotor blades is such that the shed vortex system in the hub-area is a set of helicoidal vortex sheets moving uniformly...... at the nose-area of the semi-infinite hub....

  19. Control characteristics for heating system circulation pumps; Regelkennlinien fuer Heizungsumwaelzpumpen

    Energy Technology Data Exchange (ETDEWEB)

    Kallesoe, C. S.; Bidstrup, N.; Bayer, M.

    2009-07-01

    This article takes a look at variable speed circulation pumps for space heating systems that are used in one and two-family housing. Although the control systems in most houses usually have just one characteristic, the need for several control characteristics in order to cope with varying needs is discussed. The basics of finding out what the control characteristic should look like in a particular case are discussed. Modern circulation pumps with integrated speed control and their interplay with thermostatic valves are examined and discussed. A new automatic adaptation algorithm is described and its way of working is explained. Experience gained in practice is examined.

  20. Functional evaluation of circulating hematopoietic progenitors in Noonan syndrome.

    Science.gov (United States)

    Timeus, Fabio; Crescenzio, Nicoletta; Baldassarre, Giuseppina; Doria, Alessandra; Vallero, Stefano; Foglia, Luiselda; Pagliano, Sara; Rossi, Cesare; Silengo, Margherita Cirillo; Ramenghi, Ugo; Fagioli, Franca; Cordero di Montezemolo, Luca; Ferrero, Giovanni Battista

    2013-08-01

    Noonan syndrome (NS) is an autosomal dominant disorder, characterized by short stature, multiple dysmorphisms and congenital heart defects. A myeloproliferative disorder (NS/MPD), resembling juvenile myelomonocytic leukemia (JMML), is occasionally diagnosed in infants with NS. In the present study, we performed a functional evaluation of the circulating hematopoietic progenitors in a series of NS, NS/MPD and JMML patients. The different functional patterns were compared with the aim to identify a possible NS subgroup worthy of stringent hematological follow-up for an increased risk of MPD development. We studied 27 NS and 5 JMML patients fulfilling EWOG-MDS criteria. The more frequent molecular defects observed in NS were mutations in the PTPN11 and SOS genes. The absolute count of monocytes, circulating CD34+ hematopoietic progenitors, their apoptotic rate and the number of circulating CFU-GMs cultured in the presence of decreasing concentrations or in the absence of granulocyte-macrophage colony-stimulating factor (GM-CSF) were evaluated. All JMML patients showed monocytosis>1,000/µl. Ten out of the 27 NS patients showed monocytosis>1,000/µl, which included the 3 NS/MPD patients. In JMML patients, circulating CD34+ cells were significantly increased (median, 109.8/µl; range, 44-232) with a low rate of apoptosis (median, 2.1%; range, 0.4-12.1%), and circulating CFU-GMs were hyper-responsive to GM-CSF. NS/MPD patients showed the same flow cytometric pattern as the JMML patients (median, CD34+ cells/µl, 205.7; range, 58-1374; median apoptotic rate, 1.4%; range, 0.2-2.4%) and their circulating CFU-GMs were hyper-responsive to GM-CSF. These functional alterations appeared 10 months before the typical clinical manifestations in 1 NS/MPD patient. In NS, the CD34+ absolute cell count and circulating CFU-GMs showed a normal pattern (median CD34+ cells/µl, 4.9; range, 1.3-17.5), whereas the CD34+ cell apoptotic rate was significantly decreased in comparison with the

  1. Refractory experience in circulating fluidized bed combustors, Task 7

    Energy Technology Data Exchange (ETDEWEB)

    Vincent, R.Q.

    1989-11-01

    This report describes the results of an investigation into the status of the design and selection of refractory materials for coal-fueled circulating fluidized-bed combustors. The survey concentrated on operating units in the United States manufactured by six different boiler vendors: Babcock and Wilcox, Combustion Engineering, Foster Wheeler, Keeler Dorr-Oliver, Pyropower, and Riley Stoker. Information was obtained from the boiler vendors, refractory suppliers and installers, and the owners/operators of over forty units. This work is in support of DOE's Clean Coal Technology program, which includes circulating fluidized-bed technology as one of the selected concepts being evaluated.

  2. 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

    Before researchers apply nanomaterials (NMs) in biomedicine, they need to understand the blood circulation and clearance profile of these materials in vivo. These qualities determine the balance between nanomaterial-induced activity and unwanted toxicity. NMs have heterogeneous characteristics: they combine the bulk properties of solids with the mobility of molecules, and their highly active contact interfaces exhibit diverse functionalities. Any new and unexpected circulation features and clearance patterns are of great concern in toxicological studies and pharmaceutical screens. A number of studies have reported that NMs can enter the bloodstream directly during their application or indirectly via inhalation, ingestion, and dermal exposure. Due to the small size of NMs, the blood can then transport them throughout the circulation and to many organs where they can be stored. In this Account, we discuss the blood circulation and organ clearance patterns of NMs in the lung, liver, and kidney. The circulation of NMs in bloodstream is critical for delivery of inhalable NMs to extrapulmonary organs, the delivery of injectable NMs, the dynamics of tissue redistribution, and the overall targeting of drug carriers to specific cells and organs. The lung, liver, and kidney are the major distribution sites and target organs for NMs exposure, and the clearance patterns of NMs in these organs are critical for understanding the in vivo fate of NMs. Current studies suggest that multiple factors control the circulation and organ clearance of NMs. The size, shape, surface charge, surface functional groups, and aspect ratio of NMs as well as tissue microstructures strongly influence the circulation of NMs in bloodstream, their site-specific extravasation, and their clearance profiles within organs. Therefore structure design and surface modification can improve biocompatibility, regulate the in vivo metabolism, and reduce the toxicity of NMs. The biophysicochemical interactions

  3. Fritz Schott's Contributions to the Understanding of the Ocean Circulation

    Science.gov (United States)

    Visbeck, M.

    2009-04-01

    The ocean circulation and its central significance for global climate lay at the heart of Fritz's research. In the context of hard-won data from his more than 30 research cruises to key regions of the Atlantic and Indian oceans, he made fundamental contributions to our understanding of the wind-driven and thermohaline ocean circulation. His insights and explorations of circulation and dynamics of the tropical Indian and Atlantic Oceans have led the field and provided a large part of the basis for planning large, international experiments. Fritz's work is also distinguished by his making exceptional use of modeling results, increasingly as the models have improved. His research has provided a much clearer correspondence between the observed ocean-structure and dynamical theory-noting both theoretical successes and limitations. Besides his general interest in the physical oceanography of the World Oceans, most of his research was devoted to the dynamics of tropical oceans with its intense and highly variable current systems. Concerning the Indian Ocean, Fritz's investigated the response of the Somali Current system to the variable monsoon winds in the early 1980's, obtaining high-quality, hydrographic surveys and the first long term direct measurement of ocean currents from moored arrays. His analyses and interpretations provided a synthesis of the complex circulations there. In the tropical Atlantic Ocean Fritz research focused on the western boundary circulation with important contributions to the understanding of the North Brazil Current retroflection, and the variability of the shallow and deep western boundary currents. Trying to solve the fundamental question ‘what is the role of the tropical ocean for climate variability', Fritz initiated large multinational research programs under the umbrella of the World Climate Research Projects WOCE (World Ocean Circulation Experiment) and CLIVAR (Climate Variability and Predictability). Fritz was the initiator and

  4. Isolation and number of circulated primordial germ cells (circulated-PGCs on stages of embryonic development of Gaok chicken

    Directory of Open Access Journals (Sweden)

    Kostaman T

    2013-03-01

    Full Text Available Avian primordial germ cell (PGCs show a unique migration pathway during early development. During the early embryonic development, as soon as the formation of blood vessels, PGCs enter the circulatory system and migrate to the gonadal primordial. The aim of this study was to examine the number of circulated-PGCs from Gaok chicken at different developmental stages of embryo. One hundred fertile eggs were divided into 5 groups and incubated in a portable incubator at 38oC and humidity 60%. Hatching was set according to the embryonic development stage between 14-18. The blood collection was done through the dorsal aorta using micropipette under microscope. The collected blood was grouped based on the embryonic stages and placed on a 1.5 ml eppendorf tube which had been filled with 1.000 µl of Calcium and Magnesium-free phosphate buffered saline (PBS -. The PGCs were then purified using nycodenz density gradient centrifugation. The results showed that the average number of circulated-PGCs per embryo from Gaok chicken were significantly affected by the stage of embryonic development (P < 0.05. The number of circulated-PGCs at stages 14, 15, 16, 17 and 18 were 42.8 ± 8.9, 51.0 ± 5.8, 37.6 ± 5.9, 32.8 ± 3.6 and 32.6 ± 3.2, respectively. However, the number of circulated-PGCs was no different between stage of 17 and 18. At Gaok chicken, the number of circulated-PGCs reach the peak at stage 15, it is recommended that collection of PGCs embryonic chicken from blood circulation was the best on stage 15. This information is useful in efficiency production of germline chimera and to preserve PGCs of other Indonesian native chicken.

  5. Severe accident natural circulation studies at the INEL

    Energy Technology Data Exchange (ETDEWEB)

    Bayless, P.D.; Brownson, D.A.; Dobbe, C.A.; Jones, K.R.; O`Brien, J.E.; Pafford, D.J.; Schlenker, L.D.; Tung, V.X.

    1995-02-01

    Severe accident natural circulation flows have been investigated at the Idaho National Engineering Laboratory to better understand these flows and their potential impacts on the progression of a pressurized water reactor severe accident. Parameters affecting natural circulation in the reactor vessel and hot legs were identified and ranked based on their perceived importance. Reviews of the scaling of the 1/7-scale experiments performed by Westinghouse were undertaken. RELAP5/MOD3 calculations of two of the experiments showed generally good agreement between the calculated and observed behavior. Analyses of hydrogen behavior in the reactor vessel showed that hydrogen stratification is not likely to occur, and that an initially stratified layer of hydrogen would quickly mix with a recirculating steam flow. An analysis of the upper plenum behavior in the Three Mile Island, Unit 2 reactor concluded that vapor temperatures could have been significantly higher than the temperatures seen by the control rod drive lead screws, supporting the premise that a strong natural circulation flow was likely present during the accident. SCDAP/RELAP5 calculations of a commercial pressurized water reactor severe accident without operator actions showed that the natural circulation flows enhance the likelihood of ex-vessel piping failures long before failure of the reactor vessel lower head.

  6. Tumor-derived circulating endothelial cell clusters in colorectal cancer.

    KAUST Repository

    Cima, Igor

    2016-06-29

    Clusters of tumor cells are often observed in the blood of cancer patients. These structures have been described as malignant entities for more than 50 years, although their comprehensive characterization is lacking. Contrary to current consensus, we demonstrate that a discrete population of circulating cell clusters isolated from the blood of colorectal cancer patients are not cancerous but consist of tumor-derived endothelial cells. These clusters express both epithelial and mesenchymal markers, consistent with previous reports on circulating tumor cell (CTC) phenotyping. However, unlike CTCs, they do not mirror the genetic variations of matched tumors. Transcriptomic analysis of single clusters revealed that these structures exhibit an endothelial phenotype and can be traced back to the tumor endothelium. Further results show that tumor-derived endothelial clusters do not form by coagulation or by outgrowth of single circulating endothelial cells, supporting a direct release of clusters from the tumor vasculature. The isolation and enumeration of these benign clusters distinguished healthy volunteers from treatment-naïve as well as pathological early-stage (≤IIA) colorectal cancer patients with high accuracy, suggesting that tumor-derived circulating endothelial cell clusters could be used as a means of noninvasive screening for colorectal cancer. In contrast to CTCs, tumor-derived endothelial cell clusters may also provide important information about the underlying tumor vasculature at the time of diagnosis, during treatment, and throughout the course of the disease.

  7. 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.

  8. Circulating vascular endothelial growth factor during the normal menstrual cycle

    NARCIS (Netherlands)

    Kusumanto, YH; Hospers, GAP; Sluiter, WJ; Dam, WA; Meijer, C; Mulder, NH

    2004-01-01

    Background: The purpose of the study was to investigate whether cycle-related variations in circulating Vascular Endothelial Growth Factor (VEGF) levels would increase the metastatic potential at specific times during the menstrual cycle. Materials and Methods: VEGF levels in serum and whole blood w

  9. Climate Change and the Brewer-Dobson Circulation

    Science.gov (United States)

    Rind, David

    1999-01-01

    Using GCM (General Circulation Model) simulations of the troposphere-stratosphere circulation in different climate regimes, the sensitivity of the Brewer-Dobson Circulation to climate change will be discussed. Included will be simulations of the stratosphere with increasing/doubled CO2 as done with different versions of the GISS (Goddard Institute for Space Studies) Global Climate Middle Atmosphere Model, with and without ozone response. To put the results in a broader perspective, stratospheric circulation changes from several paleoclimate simulations will also be presented, including the Last Glacial Maximum and the Paleocene, each with several different (plausible) latitudinal sea surface temperature gradients. Hence the climate changes investigated will include strong variations in baroclinic and topographic tropospheric planetary wave and gravity wave forcing, as well as global mean temperature and atmospheric CO2 levels. Results will be analyzed in terms of wave driving via E-P flux convergences and gravity wave effects, and will be shown to be strongly dependent on wave propagation characteristics.

  10. Planktonic interactions and chaotic advection in Langmuir circulation

    DEFF Research Database (Denmark)

    Bees, Martin Alan; Mezic, I.; McGlade, J.

    1998-01-01

    The role of unsteady laminar flows for planktonic communities is investigated. Langmuir circulation is used, as a typical medium-scale structure, to illustrate mechanisms for the generation of plankton patches. Two behaviours are evident: chaotic regions that help to spread plankton and locally...

  11. Balanced and Transient Dynamics of Deep and Shallow Hadley Circulations

    Science.gov (United States)

    Gonzalez, A. O.; Mora Rojas, G.; Taft, R.; Schubert, W. H.

    2014-12-01

    We examine the balanced and transient dynamics of large-scale overturning circulations in the tropical atmosphere using idealized equatorial β-plane models. When deep diabatic heating in the Intertropical Convergence Zone (ITCZ) is prescribed as slowly varying with time, the deep Hadley circulation is of first order importance. In the absence of deep diabatic heating, the interior circulation associated with Ekman pumping cannot penetrate deep into the troposphere because the resistance of fluid parcels to horizontal motion (i.e., inertial stability) is significantly smaller than their resistance to vertical motion (i.e., static stability). In this scenario, only a shallow Hadley circulation exists. The meridional asymmetry between the winter and summer deep and shallow Hadley cells is attributed to the anisotropy of the inertial stability parameter, and as the ITCZ widens meridionally or as the forcing involves higher vertical wavenumbers, the asymmetry between the winter and summer cells increases. When we prescribe both a slow and fast "switch-on" deep diabatic heating, we learn that inertia-gravity waves propagate in the meridional direction away from the ITCZ and bounce back at critical latitutes in the zonally symmetric framework. When the assumption of zonal symmetry is relaxed, we find that inertia-gravity waves propagate away from the ITCZ in not only the meridional direction but also in the zonal direction.

  12. New results on the energy of integral circulant graphs

    CERN Document Server

    Ilić, Aleksandar

    2011-01-01

    Circulant graphs are an important class of interconnection networks in parallel and distributed computing. Integral circulant graphs play an important role in modeling quantum spin networks supporting the perfect state transfer as well. The integral circulant graph $\\ICG_n (D)$ has the vertex set $Z_n = \\{0, 1, 2,..., n - 1\\}$ and vertices $a$ and $b$ are adjacent if $\\gcd(a-b,n)\\in D$, where $D \\subseteq \\{d : d \\mid n,\\ 1\\leq dcirculant graph modulo 4. Furt...

  13. DEVELOPMENT POTENTIALS AND RESEARCH NEEDS IN CIRCULATING FLUIDIZED BED COMBUSTION

    Institute of Scientific and Technical Information of China (English)

    Lothar Reh

    2003-01-01

    First a report about present status of circulating fluidized bed reactors for coal and multi-fuel combustion in power plants is given. Thereafter the development potentials and research needs for further improvement of CFB combustors operating with finely grained bed materials are discussed and recommendations for direction of further research and development work are presented.

  14. Toxicity of doxorubicin entrapped within long-circulating liposomes

    NARCIS (Netherlands)

    Daemen, T; Regts, J; Meesters, M; TenKate, MT; BakkerWoudenberg, IAJM; Scherphof, GL

    1997-01-01

    We studied the effect of doxorubicin entrapped within long-circulating liposomes (Dox-LCL) on the phagocytic capacity and bacterial blood clearance capacity of rat liver macrophages. Dox-LCL (125 nm in diameter) were composed of egg phosphatidylcholine (PC), cholesterol (CH) and poly(ethyleneglycol)

  15. 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)

  16. Cryptanalysis of the Two-Dimensional Circulation Encryption Algorithm

    Directory of Open Access Journals (Sweden)

    Bart Preneel

    2005-07-01

    Full Text Available We analyze the security of the two-dimensional circulation encryption algorithm (TDCEA, recently published by Chen et al. in this journal. We show that there are several flaws in the algorithm and describe some attacks. We also address performance issues in current cryptographic designs.

  17. After clouds sun again shines on circulating tumor cells research.

    Science.gov (United States)

    Barriere, Guislaine; Rigaud, Michel

    2013-07-01

    In the Science issue of first February 2013 Yu M et al. characterized epithelial and mesenchymal circulating tumor cells (CTC) by RNA-in situ hybridization. In this editorial we comment their results and emphasize the different CTC subpopulations arising from epithelial mesenchymal transition (EMT).

  18. Low Circulation of Zika Virus, Cambodia, 2007–2016

    Science.gov (United States)

    Duong, Veasna; Ong, Sivuth; Leang, Rithea; Huy, Rekol; Ly, Sowath; Mounier, Ugo; Ou, Teyputita; In, Saraden; Peng, Borin; Ken, Sreymom; Buchy, Philippe; Tarantola, Arnaud; Horwood, Paul F.

    2017-01-01

    We describe a retrospective study on circulation of Zika virus in Cambodia during 2007–2016 among patients with dengue-like symptoms and Aedes aegypti mosquitoes. Our findings suggest that Zika virus in Cambodia belongs to the Asia genotype, is endemic, has low prevalence, and has had low-level impact on public health. PMID:27875110

  19. Application of long-circulating liposomes to cancer photodynamic therapy.

    Science.gov (United States)

    Oku, N; Saito, N; Namba, Y; Tsukada, H; Dolphin, D; Okada, S

    1997-06-01

    Photodynamic therapy (PDT) as a cancer treatment is notable for its quite low side effects in comparison with those of chemotherapy and radiotherapy. However, the accumulation of porphyrin derivatives used in PDT into tumor tissues is rather low. Since long-circulating liposomes are known to accumulate passively into tumor tissues, we liposomalized a porphyrin derivative, benzoporphyrin derivative monoacid ring A (BPD-MA), and used these liposomes to investigate the usefulness of PDT for tumor-bearing mice. BPD-MA was liposomalized into glucuronate-modified liposomes, which are known to be long-circulating. These liposomes were injected i.v. into Balb/c mice bearing Meth A sarcoma, and tumor regression and survival time were monitored after irradiation with laser light. Tumor regression and complete curing of tumor (80% cure rate by the treatment with 6 mg/kg BPD-MA) were observed when long circulating liposomalized BPD-MA was injected and laser-irradiated. In contrast, only a 20% cure rate was obtained when the animals were treated with BPD-MA solution or BPD-MA entrapped in conventional liposomes. These results suggest that a long-circulating liposomal formulation of photo-sensitive agents is useful for PDT.

  20. The impact of oceanic heat transport on the atmospheric circulation

    CERN Document Server

    Knietzsch, Marc-Andre; Lunkeit, Frank

    2014-01-01

    A general circulation model of intermediate complexity with an idealized earthlike aquaplanet setup is used to study the impact of changes in the oceanic heat transport on the global atmospheric circulation. Focus is put on the Lorenz energy cycle and the atmospheric mean meridional circulation. The latter is analysed by means of the Kuo-Eliassen equation. The atmospheric heat transport compensates the imposed oceanic heat transport changes to a large extent in conjunction with significant modification of the general circulation. Up to a maximum about 3PW, an increase of the oceanic heat transport leads to an increase of the global mean near surface temperature and a decrease of its equator-to-pole gradient. For larger transports, the gradient is reduced further but the global mean remains approximately constant. This is linked to a cooling and a reversal of the temperature gradient in the tropics. A larger oceanic heat transport leads to a reduction of all reservoirs and conversions of the Lorenz energy cycl...

  1. Circulating folic acid in plasma: relation to folic acid fortification

    Science.gov (United States)

    The implementation of folic acid fortification in the United States has resulted in unprecedented amounts of this synthetic form of folate in the American diet. Folic acid in circulation may be a useful measure of physiologic exposure to synthetic folic acid, and there is a potential for elevated co...

  2. Propylene polymerization in a circulating slugging fluidized bed reactor

    NARCIS (Netherlands)

    Putten, van Inge Cornelia

    2004-01-01

    The work presented in this thesis is concerned with research on the riser of a circulating fluidized bed system for olefin polymerization. In the riser section, fluidization takes place in the transporting slugging mode and polymer particles are produced in the riser in a non-isothermal way. Propert

  3. Reproducibility of Neonate Ocular Circulation Measurements Using Laser Speckle Flowgraphy

    Directory of Open Access Journals (Sweden)

    Tadashi Matsumoto

    2015-01-01

    Full Text Available Measuring the ocular blood flow in neonates may clarify the relationships between eye diseases and ocular circulation abnormalities. However, no method for noninvasively measuring ocular circulation in neonates is established. We used laser speckle flowgraphy (LSFG modified for neonates to measure their ocular circulation and investigated whether this method is reproducible. During their normal sleep, we studied 16 subjects (adjusted age of 34–48 weeks whose blood flow could be measured three consecutive times. While the subjects slept in the supine position, three mean blur rate (MBR values of the optic nerve head (ONH were obtained: the MBR-A (mean of all values, MBR-V (vessel mean, and MBR-T (tissue mean, and nine blood flow pulse waveform parameters in the ONH were examined. We analyzed the coefficient of variation (COV and the intraclass correlation coefficient (ICC for each parameter. The COVs of the MBR values were all ≤10%. The ICCs of the MBR values were all >0.8. Good COVs were observed for the blowout score, blowout time, rising rate, falling rate, and acceleration time index. Although the measurement of ocular circulation in the neonates was difficult, our results exhibited reproducibility, suggesting that this method could be used in clinical research.

  4. Radioimmunoprecipitation polyethylene glycol assay for circulating Entamoeba histolytica antigens

    Energy Technology Data Exchange (ETDEWEB)

    Pillai, S.; Mohimen, A.; Mehra, S. (Calcutta Medical Research Inst., Calcutta (India). Kothari Centre of Gastroenterology)

    1982-12-17

    An assay capable of detecting circulating Entamoeba histolytica antigens in amoebiasis is described. This assay utilised a radiolabelled affinity purified rabbit anti-E. histolytica antibody that had been depleted of antibodies that cross-react with human serum proteins, and a polyethylene glycol precipitation step.

  5. Temperature stratification in a hot water tank with circulation pipe

    DEFF Research Database (Denmark)

    Andersen, Elsa

    1998-01-01

    The aim of the project is to investigate the change in temperature stratification due to the operation of a circulation pipe. Further, putting forward rules for design of pipe inlet in order not to disturb the temperature stratification in the hot water tank. A validated computer model based...

  6. The circulation of ideas in firms and markets

    NARCIS (Netherlands)

    Hellmann, T.F.; Perotti, E.C.

    2011-01-01

    Novel early stage ideas face uncertainty on the expertise needed to elaborate them, which creates a need to circulate them widely to find a match. Yet as information is not excludable, shared ideas may be stolen, reducing incentives to innovate. Still, in idea-rich environments inventors may share t

  7. A genetic contribution to circulating cytokines and obesity in children

    Science.gov (United States)

    Cytokines are considered to be involved in obesity-related metabolic diseases. Study objectives are to determine the heritability of circulating cytokine levels, to investigate pleiotropy between cytokines and obesity traits, and to present genome scan results for cytokines in 1030 Hispanic children...

  8. Characterization of circulant graphs having perfect state transfer

    CERN Document Server

    Bašić, Milan

    2011-01-01

    In this paper we answer the question of when circulant quantum spin networks with nearest-neighbor couplings can give perfect state transfer. The network is described by a circulant graph $G$, which is characterized by its circulant adjacency matrix $A$. Formally, we say that there exists a {\\it perfect state transfer} (PST) between vertices $a,b\\in V(G)$ if $|F(\\tau)_{ab}|=1$, for some positive real number $\\tau$, where $F(t)=\\exp(\\i At)$. Saxena, Severini and Shparlinski ({\\it International Journal of Quantum Information} 5 (2007), 417--430) proved that $|F(\\tau)_{aa}|=1$ for some $a\\in V(G)$ and $\\tau\\in \\R^+$ if and only if all eigenvalues of $G$ are integer (that is, the graph is integral). The integral circulant graph $\\ICG_n (D)$ has the vertex set $Z_n = \\{0, 1, 2, ..., n - 1\\}$ and vertices $a$ and $b$ are adjacent if $\\gcd(a-b,n)\\in D$, where $D \\subseteq \\{d : d \\mid n,\\ 1\\leq d

  9. The eigenvalues and energy of integral circulant graphs

    Directory of Open Access Journals (Sweden)

    Mohsen Mollahajiaghaei

    2012-09-01

    Full Text Available A graph is called textit{circulant} if it is a Cayley graph on acyclic group, i.e. its adjacency matrix is circulant. Let $D$ be aset of positive, proper divisors of the integer $n>1$. Theintegral circulant graph $ICG_{n}(D$ has the vertex set$mathbb{Z}_{n}$ and the edge set E$(ICG_{n}(D= {{a,b};gcd(a-b,nin D }$. Let $n=p_{1}p_{2}cdots p_{k}m$, where$p_{1},p_{2},cdots,p_{k}$ are distinct prime numbers and$gcd(p_{1}p_{2}cdots p_{k},m=1$. The open problem posed in paper[A. Ili'{c}, The energy of unitary Cayley graphs, Linear AlgebraAppl., 431 (2009 1881--1889] about calculating the energy of anarbitrary integral circulant $ICG_{n}(D$ is completely solved inthis paper, where $D={p_{1},p_{2},ldots,p_{k} } $.

  10. Realisation of microstrip junction circulator using LTCC technology

    DEFF Research Database (Denmark)

    Jensen, Thomas; Krozer, V; Kjærgaard, Claus

    2011-01-01

    An integrated circulator based on low-temperature cofired ceramics (LTCC) tapes and LTCC compatible ferrite tapes has been developed for the first time and its performance has been verified experimentally. The insertion loss is less than 2 dB and the isolation is better than 25 dB with a centre f...

  11. Coolant rate distribution in horizontal steam generator under natural circulation

    Energy Technology Data Exchange (ETDEWEB)

    Blagovechtchenski, A.; Leontieva, V.; Mitrioukhin, A. [St. Petersburg State Technical Univ. (Russian Federation)

    1997-12-31

    In the presentation the major factors determining the conditions of NCC (Natural Coolant Circulation) in the primary circuit and in particular conditions of coolant rate distribution on the horizontal tubes of PGV-1000 in NPP with VVER-1000 under NCC are considered. 5 refs.

  12. Nucleic acids in circulation: Are they harmful to the host?

    Indian Academy of Sciences (India)

    Indraneel Mittra; Naveen Kumar Nair; Pradyumna Kumar Mishra

    2012-06-01

    It has been estimated that 1011–1012 cells, primarily of haematogenous origin, die in the adult human body daily, and a similar number is regenerated to maintain homeostasis. Despite the presence of an efficient scavenging system for dead cells, considerable amounts of fragmented genetic material enter the circulation in healthy individuals. Elevated blood levels of extracellular nucleic acids have been reported in various disease conditions; such as ageing and age-related degenerative disorders, cancer; acute and chronic inflammatory conditions, severe trauma and autoimmune disorders. In addition to genomic DNA and nucleosomes, mitochondrial DNA is also found in circulation, as are RNA and microRNA. There is extensive literature that suggests that extraneously added nucleic acids have biological actions. They can enter into cells in vitro and in vivo and induce genetic transformation and cellular and chromosomal damage; and experimentally added nucleic acids are capable of activating both innate and adaptive immune systems and inducing a sterile inflammatory response. The possibility as to whether circulating nucleic acids may, likewise, have biological activities has not been explored. In this review we raise the question as to whether circulating nucleic acids may have damaging effects on the host and be implicated in ageing and diverse acute and chronic human pathologies.

  13. Circulating Heat Shock Protein 70 in Health, Aging and Disease

    Directory of Open Access Journals (Sweden)

    Demanet Christian

    2011-03-01

    Full Text Available Abstract Background Heat shock proteins (Hsp are ubiquitously synthesised in virtually all species and it is hypothesised that they might have beneficial health effects. Recent studies have identified circulating Hsp as an important mediator in inflammation - the effects of low-grade inflammation in the aging process are overwhelming. While much is known about intracellular Hsp70, scant data exist on circulating Hsp70 in the aging context. Therefore, the objectives of this study were to investigate the effect of age and disease on circulating Hsp70 and, in particular, to evaluate the association between circulating Hsp70 and inflammatory parameters. Results Serum Hsp70, Interleukin (IL -10, IL-6 and Tumor Necrosis Factor (TNF alpha concentrations were determined in 90 hospitalised geriatric patients (aged 83 ± 6 years and in 200 community-dwelling control subjects (100 elderly, aged 74 ± 5 years, and 100 young, aged 23 ± 3 years. In the community-dwelling elderly, serum Hsp70 and IL-10 concentrations were significantly lower and IL-6 was significantly higher when compared to healthy young control subjects. Elderly patients presenting inflammation (CRP serum levels ≥5 mg/L showed significantly (p = 0.007 higher Hsp70 values; and Hsp70 correlated positively (p Conclusions The present data provide new evidence that serum concentration of Hsp70 decreases with age in a normal population. Our study also shows that higher levels of Hsp70 are associated with inflammation and frailty in elderly patients.

  14. Forcing mechanisms of the Bay of Bengal circulation

    Digital Repository Service at National Institute of Oceanography (India)

    Vinayachandran, P.N.; Shetye, S.R.; Sengupta, D.; Gadgil, S.

    in the north. To identify the principal mechanisms governing this cycle, we carried out experiments with modified winds. When spatially uniform wind stress was applied only over the Bay, the circulation is similar to, but weaker than the observed, and can...

  15. Single-particle behaviour in circulating fluidized beds

    DEFF Research Database (Denmark)

    Weinell, Claus Erik; Dam-Johansen, Kim; Johnsson, Jan Erik

    1997-01-01

    This paper describes an experimental investigation of single-particle behaviour in a cold pilot-scale model of a circulating fluidized bed combustor (CFBC). In the system, sand is recirculated by means of air. Pressure measurements along the riser are used to determine the suspension density...

  16. Oxidative stress, circulating antioxidants, and dietary preferences in songbirds.

    Science.gov (United States)

    Alan, Rebecca R; McWilliams, Scott R

    2013-03-01

    Oxidative stress is an unavoidable consequence of metabolism and increases during intensive exercise. This is especially problematic for migratory birds that metabolize fat to fuel long-distance flight. Birds can mitigate damage by increasing endogenous antioxidants (e.g. uric acid) or by consuming dietary antioxidants (e.g. tocopherol). During flight, birds may increase protein catabolism of lean tissue which may increase circulating uric acid and many birds also consume an antioxidant-rich frugivorous diet during autumn migration. We evaluated three related hypotheses in a migratory passerine: (1) protein consumption is positively related to circulating antioxidants, (2) a dietary oxidative stressor [i.e. polyunsaturated fatty acid (PUFA)] influences antioxidant capacity and oxidative damage, and (3) oxidative stress influences dietary antioxidant preferences. White-throated Sparrows (Zonotrichia albicollis) consuming a high protein diet increased circulating uric acid; however, uric acid, antioxidant capacity, and oxidative stress did not differ between birds consuming a high PUFA versus a low PUFA diet, despite increased oxidative damage in high PUFA birds. Birds did not prefer antioxidant-rich diets even when fed high PUFA, low protein. We conclude that White-throated Sparrows successfully mitigated oxidative damage associated with a high PUFA diet and mounted an endogenous antioxidant response independent of uric acid, other circulating antioxidants, and dietary antioxidants.

  17. Circulation Produced by a Flapping Wing During Stroke Reversal

    Science.gov (United States)

    Burge, Matthew; Ringuette, Matthew

    2016-11-01

    We investigate the circulation behavior of the 3D flow structures formed during the stroke-reversal of a 2-degree-of-freedom flapping wing in hover. Previous work has related circulation peaks to the unsteady wing kinematics and forces. However, information from experiments detailing contributions from the multiple, 3D flow structures is lacking. The objective of this work is to quantitatively study the spanwise circulation as well as the spanwise flow which advects vorticity in the complex loop topology of a flapping wing during stroke reversal. We analyze the flow features of a scaled wing model using multi-plane stereo digital particle image velocimetry in a glycerin-water mixture. Data plane locations along the wing span are inspired by the time-resolved behavior of the 3D vortex structures observed in our earlier flow visualization studies. As with our prior work, we vary dimensionless parameters such as the pitching reduced frequency to understand their effect on the circulation. This research provides insight into the vortex dynamics produced by the coupled rotational and pitching wing motions during stroke reversal, when lift generation is challenging. This work is supported by the National Science Foundation, Award Number 1336548, supervised by Dr. Dimitrios Papavassiliou.

  18. Evaluation of circulating YKL-40 levels in idiopathic interstitial pneumonias

    NARCIS (Netherlands)

    Korthagen, Nicoline M; van Moorsel, Coline H M; Zanen, Pieter; Ruven, Henk J; Grutters, Jan C

    2014-01-01

    INTRODUCTION: YKL-40 is a novel biomarker in diseases with inflammation, fibrosis and tissue remodelling. Previously, circulating YKL-40 was shown to be elevated in patients with idiopathic pulmonary fibrosis (IPF) and was associated with survival. OBJECTIVE: To compare YKL-40 serum levels between I

  19. Automated Bilingual Circulation System Using PC Local Area Networks.

    Science.gov (United States)

    Iskanderani, A. I.; Anwar, M. A.

    1992-01-01

    Describes a local automated bilingual circulation system using personal computers in a local area network that was developed at King Abdulaziz University (Saudi Arabia) for Arabic and English materials. Topics addressed include the system structure, hardware, major features, storage requirements, and costs. (nine references) (LRW)

  20. Circulating Fibrocytes Are Increased in Neonates with Bronchopulmonary Dysplasia

    Science.gov (United States)

    Li, Chun; Li, Xiaoyu; Deng, Chun; Guo, Chunbao

    2016-01-01

    Background Bronchopulmonary dysplasia (BPD) is characterized by the aberrant remodeling of the lung parenchyma, resulting from accumulation of fibroblasts or myofibroblasts. Circulating fibrocytes are implied in pulmonary fibrosis, but whether these cells are associated with the development of BPD or the progressive fibrosis is unknown. The aim of the present study was to investigate the occurrence of fibrocytes in peripheral venous blood and explore whether these cells might be associated with severity of BPD. Methods We investigated circulating fibrocytes in 66 patients with BPD, 23 patients with acute respiratory distress syndrome(ARDS) and 11 normal subjects. Circulating fibrocytes were defined and quantified as cells positive for CD45 andcollagen-1 by flow cytometry. Furthermore, serum SDF-1/CXCL12 and TGF-β1 were evaluated using ELISA methods. We also investigated the clinical value of fibrocyte counts by comparison with standard clinical parameters. Results The patients with BPD had significantly increased numbers of fibrocytes compared to the controls (p fibrocytes and pulmonary hypertension or oxygen saturation (p Fibrocyte numbers were not correlated with other clinical or functional variables or radiologic severity scores. The fibrocyte attractant chemokine CXCL12 increased in plasma (p fibrocytes are increased in patients with BPD and may contribute to pulmonary fibrosis in BPD. Circulating fibrocytes, likely recruited through the CXCR4/CXCL12 axis, might contribute to the production of TGF-β1 for the expansion of fibroblast/myofibroblast population in BPD. PMID:27309347

  1. 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.

  2. Circulation, Systems, and Space: A Commentary on Interrelationships.

    Science.gov (United States)

    Sinclair, Dorothy

    Membership in a library system, consortium, council, or network can affect a library's circulation in a number of ways that, in turn, impact on the library's space requirements. Reciprocal borrowing privileges may change the library use patterns of patrons, increasing traffic in an especially convenient, or well-supplied library. A reciprocal…

  3. Axisymmetrically Tropical Cyclone-like Vortices with Secondary Circulations

    CERN Document Server

    Sun, Liang

    2013-01-01

    The secondary circulation of the tropical cyclone (TC) is related to its formation and intensification, thus becomes very important in the studies. The analytical solutions have both the primary and secondary circulation in a three-dimensionally nonhydrostatic and adiabatic model. We prove that there are three intrinsic radiuses for the axisymmetrically ideal incompressible flow. The first one is the radius of maximum primary circular velocity $r_m$. The second one is radius of the primary kernel $r_k>r_m$, across which the vorticity of the primary circulation changes sign and the vertical velocity changes direction. The last one is the radius of the maximum primary vorticity $r_d$, at which the vertical flow of the secondary circulation approaches its maximum, and across which the radius velocity changes sign. The first TC-like vortex solution has universal inflow or outflow. The relations between the intrinsic length scales are $r_k=\\sqrt{2}r_m$ and $r_d=2r_m$. The second one is a multi-planar solution, per...

  4. Library Book Circulation and the Beta-Binomial Distribution.

    Science.gov (United States)

    Gelman, E.; Sichel, H. S.

    1987-01-01

    Argues that library book circulation is a binomial rather than a Poisson process, and that individual book popularities are continuous beta distributions. Three examples demonstrate the superiority of beta over negative binomial distribution, and it is suggested that a bivariate-binomial process would be helpful in predicting future book…

  5. Determinants of the hyperdynamic circulation and central hypovolaemia in cirrhosis

    DEFF Research Database (Denmark)

    Møller, Søren; Hobolth, Lise; Winkler, Christine;

    2011-01-01

    Patients with advanced cirrhosis often develop a hyperdynamic circulation with central hypovolaemia. The events that initiate the systemic haemodynamic abnormalities and the coupling of these factors to splanchnic haemodynamics are still unclear. Objective On the basis of a large population of pa...

  6. Late Posthemorrhagic Structural and Functional Changes in Pulmonary Circulation Arteries

    Directory of Open Access Journals (Sweden)

    S. A. Andreyeva

    2008-01-01

    Full Text Available Objective: to reveal the major regularities and mechanisms of morphological changes in the rat pulmonary circulation arteries in the late posthemorrhagic period and to compare them with age-related features of the vessels. Materials and methods: experiments to generate graduated hemorrhagic hypotension with the blood pressure being maintained at 40 mm Hg were carried out on young (5—6-month albino male Wistar rats. Throughout hypotension and 60 days after blood loss, the blood was tested to determine low and average molecular-weight substances by spectrophotometry and the pro- and antioxidative systems by chemiluminescence. Pulmonary circulation arteries were morphologically studied in young animals, rats in the late posthemorrhagic period and old (24—25-month rats. Results. Sixty-minute hemorrhagic hypotension leads to the development of endotoxemia and imbalance of the pro- and antioxidative systems, the signs of which are observed in the late periods (2 months after hypotension. At the same time, the posthemorrhagic period is marked by the significant pulmonary circulation arterial morphological changes comparable with their age-related alterations in old rat. This shows up mainly in the reorganization of a connective tissue component in the vascular wall: the elevated levels of individual collagen fibers, their structural changes, elastic medial membrane destruction and deformity. At the same time, there is a change in the morphometric parameters of vessels at all study stages while their lowered flow capacity is only characteristic for intraorgan arteries. Conclusion: The increased activity of free radical oxidation and endotoxemia may be believed to be one of the causes of morphological changes in pulmonary circulation arteries in the late posthemorrhagic period, which is similar to age-related vascular alterations. Key words: hemorrhagic hypotension, pulmonary circulation arteries, free radical oxidation, endotoxemia, remodeling, late

  7. Biogeochemical Proxies in Scleractinian Corals used to Reconstruct Ocean Circulation

    Energy Technology Data Exchange (ETDEWEB)

    Guilderson, T P; Kashgarian, M; Schrag, D P

    2001-02-23

    We utilize monthly {sup 14}C data derived from coral archives in conjunction with ocean circulation models to address two questions: (1) how does the shallow circulation of the tropical Pacific vary on seasonal to decadal time scales and (2) which dynamic processes determine the mean vertical structure of the equatorial Pacific thermocline. Our results directly impact the understanding of global climate events such as the El Nino-Southern Oscillation (ENSO). To study changes in ocean circulation and water mass distribution involved in the genesis and evolution of ENSO and decadal climate variability, it is necessary to have records of climate variables several decades in length. Continuous instrumental records are limited because technology for continuous monitoring of ocean currents has only recently been available, and ships of opportunity archives such as COADS contain large spatial and temporal biases. In addition, temperature and salinity in surface waters are not conservative and thus can not be independently relied upon to trace water masses, reducing the utility of historical observations. Radiocarbon ({sup 14}C) in sea water is a quasi-conservative water mass tracer and is incorporated into coral skeletal material, thus coral {sup 14}C records can be used to reconstruct changes in shallow circulation that would be difficult to characterize using instrumental data. High resolution {Delta}{sup 14}C timeseries such as these, provide a powerful constraint on the rate of surface ocean mixing and hold great promise to augment onetime surveys such as GEOSECS and WOCE. These data not only provide fundamental information about the shallow circulation of the Pacific, but can be used as a benchmark for the next generation of high resolution ocean models used in prognosticating climate change.

  8. Circulating perivascular progenitors: a target of PDGFR inhibition.

    Science.gov (United States)

    Mancuso, Patrizia; Martin-Padura, Ines; Calleri, Angelica; Marighetti, Paola; Quarna, Jessica; Rabascio, Cristina; Braidotti, Paola; Bertolini, Francesco

    2011-09-15

    Cancer blood vessels consist of two interacting types of cells: inner lining endothelial cells (ECs) and surrounding perivascular cells (pericytes, vascular smooth muscle cells or mural cells). PDGFRbeta(CD140b)+ progenitor perivascular cells (PPC) can differentiate into pericytes and regulate vessel stability and vascular survival in tumors. Similarly to what we have done with circulating ECs and progenitors, we developed a flow cytometry procedure for the enumeration of circulating PPCs and the study of their viability in murine models of cancer and in cancer patients. DNA+CD45-CD31-CD140b+ cells were enumerated by six-colour flow cytometry, their morphology was studied by electron microscopy, PPC specificity confirmed by reverse trascription-PCR (RT-PCR) expression of CD140b mRNA, and viability assessed by Syto16 and 7AAD. In preclinical marrow transplantation studies, 9 ± 4% of circulating PPCs were derived from the marrow donor. PPCs were increased in cancer-bearing mice and in patients affected by some types of cancer. At variance with the kinetic of circulating endothelial progenitors, high-dose cyclophosphamide reduced the number of viable PPCs. The administration of sunitinib, a drug known to inhibit PDGFR, was associated in murine models and in cancer patients with an increase of apoptotic/necrotic circulating PPC, suggesting a direct targeting of these cells. PPC enumeration might be studied as a tool for the definition of the optimal biologic dose of anti-PDGFR drugs and investigated clinically as a possible predictive/prognostic tool in patients receiving anti-PDGFR drugs.

  9. Circulating Fibrocytes Are Increased in Neonates with Bronchopulmonary Dysplasia.

    Directory of Open Access Journals (Sweden)

    Chun Li

    Full Text Available Bronchopulmonary dysplasia (BPD is characterized by the aberrant remodeling of the lung parenchyma, resulting from accumulation of fibroblasts or myofibroblasts. Circulating fibrocytes are implied in pulmonary fibrosis, but whether these cells are associated with the development of BPD or the progressive fibrosis is unknown. The aim of the present study was to investigate the occurrence of fibrocytes in peripheral venous blood and explore whether these cells might be associated with severity of BPD.We investigated circulating fibrocytes in 66 patients with BPD, 23 patients with acute respiratory distress syndrome(ARDS and 11 normal subjects. Circulating fibrocytes were defined and quantified as cells positive for CD45 andcollagen-1 by flow cytometry. Furthermore, serum SDF-1/CXCL12 and TGF-β1 were evaluated using ELISA methods. We also investigated the clinical value of fibrocyte counts by comparison with standard clinical parameters.The patients with BPD had significantly increased numbers of fibrocytes compared to the controls (p < 0.01. Patients with ARDS were not different from healthy control subjects. There was a correlation between the number of fibrocytes and pulmonary hypertension or oxygen saturation (p < 0.05. Fibrocyte numbers were not correlated with other clinical or functional variables or radiologic severity scores. The fibrocyte attractant chemokine CXCL12 increased in plasma (p < 0.05 and was detectable in the bronchoalveolar lavage fluid of 40% of the patients but not in controls.These findings indicate that circulating fibrocytes are increased in patients with BPD and may contribute to pulmonary fibrosis in BPD. Circulating fibrocytes, likely recruited through the CXCR4/CXCL12 axis, might contribute to the production of TGF-β1 for the expansion of fibroblast/myofibroblast population in BPD.

  10. Circulation Organization Innovation:Shorten or Lengthen Circulation Time%流通组织创新:缩短与延长流通时间

    Institute of Scientific and Technical Information of China (English)

    崔向阳

    2015-01-01

    Based on Marxist circulation time theory,circulation time the one of the important variables having impact on circulation organization. Circulation time plays its role in having impact on innovation in circulation organization from the longitudinal and horizontal aspects,which leads to the integration and convergence of circulation industry. From the longitudinal aspect,the innovation of circulation organization is oriented to shorten the circulation time,which leads to the compression of circulation links,and the reduction of circulation cost;and it includes such four models as the shortening of purchase time,the shortening of selling time,the convergence of purchase and selling,and the convergence of circulation and IT. From the horizontal aspect,the innovation of circulation organization is oriented to lengthen the circulation time,which leads to the extension of industrial chain of circulation industry and the enlargement of scale of circulation industry;it includes such four models as the integration of the function of circulation industry itself,the integration of circulation industry with agricultural industry,the integration of circulation industry with manufacturing industry,and the integration of circulation industry with other service industries.%根据马克思的流通时间理论,流通时间是影响流通组织创新的重要变量。流通时间从纵横两个方面对流通组织创新发挥作用,导致流通业的融合与整合。从纵的方面说,是缩短流通时间导向的,要求压缩流通环节,节约流通费用,包括节约购买时间、节约销售时间、融合购买与销售阶段、融合流通业和信息技术产业等四种模式。从横的方面说,是延长流通时间导向的,要求延伸流通产业链条,扩大流通规模,包括流通业整合自身功能、流通业整合农业、流通业整合制造业、流通业整合其他服务业等四种模式。

  11. On Optimal Backward Perturbation Analysis for the Linear System with Skew Circulant Coefficient Matrix

    Science.gov (United States)

    Jiang, Zhaolin; Shen, Nuo; Zhou, Jianwei

    2013-01-01

    We first give the style spectral decomposition of a special skew circulant matrix C and then get the style decomposition of arbitrary skew circulant matrix by making use of the Kronecker products between the elements of first row in skew circulant and the special skew circulant C. Besides that, we obtain the singular value of skew circulant matrix as well. Finally, we deal with the optimal backward perturbation analysis for the linear system with skew circulant coefficient matrix on the base of its style spectral decomposition. PMID:24369488

  12. Study on biomass circulation and gasification performance in a clapboard-type internal circulating fluidized bed gasifier.

    Science.gov (United States)

    Zhou, Zhao-qiu; Ma, Long-long; Yin, Xiu-li; Wu, Chuang-zhi; Huang, Li-cheng; Wang, Chu

    2009-01-01

    We investigated the solid particle flow characteristics and biomass gasification in a clapboard-type internal circulating fluidized bed reactor. The effect of fluidization velocity on particle circulation rate and pressure distribution in the bed showed that fluidization velocities in the high and low velocity zones were the main operational parameters controlling particle circulation. The maximum internal circulation rates in the low velocity zone came almost within the range of velocities in the high velocity zone, when u(H)/u(mf)=2.2-2.4 for rice husk and u(H)/u(mf)=3.5-4.5 for quartz sand. In the gasification experiment, the air equivalence ratio (ER) was the main controlling parameter. Rice husk gasification gas had a maximum heating value of around 5000 kJ/m(3) when ER=0.22-0.26, and sawdust gasification gas reached around 6000-6500 kJ/m(3) when ER=0.175-0.24. The gasification efficiency of rice husk reached a maximum of 77% at ER=0.28, while the gasification efficiency of sawdust reached a maximum of 81% at ER=0.25.

  13. State of the Art Report for a Bearing for VHTR Helium Circulator

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jae Seon; Song, Kee Nam; Kim, Yong Wan; Lee, Won Jae

    2008-10-15

    A helium circulator in a VHTR(Very High Temperature gas-cooled Reactor) plays a core role which translates thermal energy at high temperature from a nuclear core to a steam generator. Helium as a operating coolant circulates a primary circuit in high temperature and high pressure state, and controls thermal output of a nuclear core by controlling flow rate. A helium circulator is the only rotating machinery in a VHTR, and its reliability should be guaranteed for reliable operation of a reactor and stable production of hydrogen. Generally a main helium circulator is installed on the top of a steam generator vessel, and helium is circulated only by a main helium circulator in a normal operation state. An auxiliary or shutdown circulator is installed at the bottom of a reactor vessel, and it is an auxiliary circulator for shutting down a reactor in case of refueling or accelerating cooling down in case of fast cooling. Since a rotating shaft of a helium circulator is supported by bearings, bearings are the important machine elements which determines reliability of a helium circulator and a nuclear reactor. Various types of support bearings have been developed and applied for circulator bearings since 1960s, and it is still developing for developing VHTRs. So it is necessary to review and analyze the current technical state of helium circulator support bearings to develop bearings for Koran developing VHTR helium circulator.

  14. Peasant Household Oriented Land Circulation from the Perspective of State Governance

    Institute of Scientific and Technical Information of China (English)

    YU Chuan-gang

    2012-01-01

    Based on the state governance background of peasant household oriented land circulation,I analyzed characteristics of peasant household oriented land circulation.The characteristics mainly include uncertain definition of rural land circulation,significant off-media feature of land circulation,long-term land circulation contract,farmers’ preference of peasant household oriented land circulation,and progressive path of land circulation.The essential feature is the progressive mode of land circulation.Under the existing property right,it realizes the perfect combination of modern production factors and traditional agricultural,and the combination of traditional family safeguarding function and modern social mutual growth spirit.Thus,it shows relative independence and manifests the idea of common prosperity.The opportunity cost of peasant household oriented land circulation is minimal,institutional cost will increase circulation risk,and what’s more,the cost for state governance of peasant household oriented land circulation is minimal.It comes to conclusion that building proper and harmonious land circulation mechanism is responsibility of central government and favorable for healthy development of peasant household oriented land circulation.

  15. 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...

  16. Mutations in circulating mitochondrial DNA: Cassandra of oral cancer?

    Science.gov (United States)

    Kandel, Eugene S

    2012-07-01

    Cell-free circulating nucleic acids in human blood are increasing being researched as a source of diagnostic and prognostic biomarkers for clinical oncology. High copy number per cell and frequent mutations in various malignancies make mitochondrial genome an attractive target for such an investigation, but practical development and validation of biomarkers based on cell-free mitochondrial DNA has been lagging. Uzawa and colleagues report in the July issue of Oncotarget that in a retrospective study of patients with oral cancer the load of mutant mitochondrial DNA in patient's serum was a strong indicator of postoperative recurrence. Based on these observations, the predictive value of circulating mutant mitochondrial DNA merits further evaluation in patients with oral and other malignancies.

  17. Prognostic value of circulating CD34+ cells in myelodysplastic syndromes.

    Science.gov (United States)

    Cesana, Clara; Klersy, Catherine; Brando, Bruno; Nosari, Annamaria; Scarpati, Barbara; Scampini, Linda; Molteni, Alfredo; Nador, Guido; Santoleri, Luca; Formenti, Marta; Valentini, Marina; Mazzone, Antonino; Morra, Enrica; Cairoli, Roberto

    2008-11-01

    We studied circulating (C)CD34(+) cells by flow cytometry in 96 patients with myelodysplastic syndromes (MDS) at diagnosis, and in a subset of 35 cases during follow-up. CCD34(+) counts were stratified within both International Prognostic Scoring System (IPSS) and World Health Organization (WHO) categories. Counts >10/microl were associated with poorer leukemia-free survival, a prognostic value for evolution independent from that of WHO, and a higher progression probability within intermediate-risk IPSS and WHO classes. When serial measurements were performed, counts >10/microl more frequently correlated to evolution. Separating newly diagnosed patients on the basis of 10/microl cut-off of circulating CD34(+) cells retains prognostic utility, especially in intermediate-risk MDS.

  18. Cytomorphology of Circulating Colorectal Tumor Cells: A Small Case Series

    Directory of Open Access Journals (Sweden)

    Dena Marrinucci

    2010-01-01

    Full Text Available Several methodologies exist to enumerate circulating tumor cells (CTCs from the blood of cancer patients; however, most methodologies lack high-resolution imaging, and thus, little is known about the cytomorphologic features of these cells. In this study of metastatic colorectal cancer patients, we used immunofluorescent staining with fiber-optic array scanning technology to identify CTCs, with subsequent Wright-Giemsa and Papanicolau staining. The CTCs were compared to the corresponding primary and metastatic tumors. The colorectal CTCs showed marked intrapatient pleomorphism. In comparison to the corresponding tissue biopsies, cells from all sites showed similar pleomorphism, demonstrating that colorectal CTCs retain the pleomorphism present in regions of solid growth. They also often retain particular cytomorphologic features present in the patient's primary and/or metastatic tumor tissue. This study provides an initial analysis of the cytomorphologic features of circulating colon cancer cells, providing a foundation for further investigation into the significance and metastatic potential of CTCs.

  19. Lymph vessels: the forgotten second circulation in health and disease.

    Science.gov (United States)

    Adamczyk, Lukasz A; Gordon, Kristiana; Kholová, Ivana; Meijer-Jorna, Lorine B; Telinius, Niklas; Gallagher, Patrick J; van der Wal, Allard C; Baandrup, Ulrik

    2016-07-01

    The lymphatic circulation is still a somewhat forgotten part of the circulatory system. Despite this, novel insights in lymph angiogenesis in health and disease, application of immune markers for lymphatic growth and differentiation and also the introduction of new imaging techniques to visualize the lymphatic circulation have improved our understanding of lymphatic function in both health and disease, especially in the last decade. These achievements yield better understanding of the various manifestations of lymph oedemas and malformations, and also the patterns of lymphovascular spread of cancers. Immune markers that recognize lymphatic endothelium antigens, such as podoplanin, LYVE-1 and Prox-1, can be successfully applied in diagnostic pathology and have revealed (at least partial) lymphatic differentiation in many types of vascular lesions.

  20. Fractal analysis of circulating platelets in type 2 diabetic patients.

    Science.gov (United States)

    Bianciardi, G; Tanganelli, I

    2015-01-01

    This paper investigates the use of computerized fractal analysis for objective characterization by means of transmission electron microscopy of the complexity of circulating platelets collected from healthy individuals and from type 2 diabetic patients, a pathologic condition in which platelet hyperreactivity has been described. Platelet boundaries were extracted by means of automatically image analysis. Local fractal dimension by box counting (measure of geometric complexity) was automatically calculated. The results showed that the platelet boundary observed by electron microscopy is fractal and that the shape of the circulating platelets is significantly more complex in the diabetic patients in comparison to healthy subjects (p fractal analysis of platelet shape by transmission electron microscopy can provide accurate, quantitative, data to study platelet activation in diabetes mellitus.

  1. [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.

  2. Circulation-preserving plane flows of incompressible viscous fluids

    Science.gov (United States)

    Yin, W.-L.

    1983-06-01

    The present investigation is concerned with a systematic use of the method of complex variables in a study of (generally unsteady) plane solutions of the Navier-Stokes equation. Circulation-preserving flows are considered in the investigation. However, the employed method can also be applied to more general cases. A circulation-preserving plane solution of the Navier-Stokes equation possesses a biharmonic stream function. The stream function may, therefore, be expressed in terms of two complex analytic functions, taking into account Goursat's representation. Attention is given to differential equations in the complex form, the case of steady vorticity, the case of unsteady vorticity with a spatially constant vorticity gradient, solutions with logarithmic vorticity fields, and a proof of completeness.

  3. Spin-Down of the North Atlantic Subpolar Circulation

    Science.gov (United States)

    Hakkinen, S.; Rhines, P. B.

    2004-01-01

    Dramatic changes have occurred in the mid-to-high-latitude North Atlantic Ocean as evidenced by TOPEX/Poseidon observations of sea surface height (SSH) in the subpolar gyre and the Gulf Stream. Analysis of altimeter data shows that subpolar SSH has increased during the 1990s and the geostrophic velocity derived from altimeter data shows a decline in the gyre circulation. Direct current-meter observations in the boundary current of the Labrador Sea support the trend in the 199Os, and, together with hydrographic data show that in the mid-late 1990s the trend extends deep in the water column. We find that buoyancy forcing over the northern North Atlantic has a dynamic effect consistent with the altimeter data and hydrographic observations: a weak thermohaline forcing and the subsequent decay of the domed structure of the subpolar isopycnals would give rise to the observed anticyclonic circulation trend.

  4. Advances on circulating fetal DNA in maternal plasma

    Institute of Scientific and Technical Information of China (English)

    FU Xian-hu; CHEN Han-ping

    2007-01-01

    @@ The discovery of cell-free fetal DNA in maternal plasma in 1997 has opened up new possibilities for noninvasive diagnosis.1 By RT-PCR, circulating fetal DNA can be detected in the plasma of pregnant women,even in the first trimester of pregnancy,2,3 and thus can be used for noninvasive prenatal diagnosis of sex-linked disorders,4-6 the RhD status of fetuses,7 and single gene disorders such as beta-thalassaemia,8,9 congenital adrenal hyperplasia,10 and achondroplasia.11 In addition,quantitative aberrations of circulating fetal DNA may indicate various pregnancy-associated disorders,including1 Preeclampsia,12-14 preterm labor15,16 and fetal trisomy 21.17

  5. Circulating Extracellular microRNA in Systemic Autoimmunity

    DEFF Research Database (Denmark)

    Heegaard, Niels H. H.; Carlsen, Anting Liu; Skovgaard, Kerstin

    2015-01-01

    MicroRNAs (miRNAs) are differentially regulated in healthy, activated, inflamed, neoplastic, or otherwise pathological cells and tissues. While their main functions are executed intracellularly, many miRNAs can reproducibly be detected extracellularly in plasma and serum. This circulating......, extracellular miRNA is protected against degradation by complexation with carrier proteins and/or by being enclosed in subcellular membrane vesicles. This, together with their tissue- and disease-specific expression, has fuelled the interest in using circulating microRNA profiles as harbingers of disease, i.......e., as diagnostic analytes and as clues to dysregulated pathways in disease. Many studies show that inflammation and immune dysregulation, e.g., in autoimmune diseases, are associated with distinct miRNA expression changes in targeted tissues and in innate and adaptive immunity cells such as lymphocytes, natural...

  6. A GM cryocooler with cold helium circulation for remote cooling

    Science.gov (United States)

    Wang, Chao; Brown, Ethan

    2014-01-01

    A GM cryocooler with new cold helium circulation system has been developed at Cryomech. A set of check valves connects to the cold heat exchanger to convert a small portion of AC oscillating flow in the cold head to a DC gas flow for circulating cold helium in the remote loop. A cold finger, which is used for remote cooling, is connected to the check valves through a pair of 5 m long vacuum insulated flexible lines. The GM cryocooler, Cryomech model AL125 having 120 W at 80 K, is employed in the testing. The cold finger can provide 50 W at 81 K for the power input of 4.1 kW and 70.5 W at 81.8 K for the power input of 6 kW. This simple and low cost design is very attractive for some applications in the near future.

  7. Circulating fluidized bed coal-saving optimization control method

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, Tengfei; Li, Dewei; Xi, Yugeng; Zhou, Wu [Shanghai Jiao Tong Univ., Shanghai (China). Dept. of Automation; Ministry of Education, Shanghai (China). Key Lab. of System Control and Information Processing; Yin, Debin [Shanghai Xinhua Control Technology (Group) Co., Ltd., Shanghai (China)

    2013-07-01

    The circulating fluidized bed boiler is widely used in thermal power plants. With the proposal of energy-saving emission reduction, how to reduce coal consumption while ensure the output steam quality at the same time has become an important topic. This paper combines the technology of RTO (real-time optimization) and zone control in DMC (dynamic matrix control) to achieve this goal. The proposed method adds the coal consumption into the objective function of DMC controller and the operation point of the boiler is permitted to change within a zone which can be set according to the actual requirements of the circulating fluidized bed boiler. The zone control in DMC provides the freedom to reduce the coal consumption and achieves the economic optimal target. Compared to the simple use of constrained DMC control, the proposed method is verified to be remarkable coal-saving by the case study of a 150 t/h boiler of a power plant in Sichuan.

  8. Meridional Circulation in Solar and Stellar Convection Zones

    CERN Document Server

    Featherstone, Nicholas A

    2015-01-01

    We present a series of 3-D nonlinear simulations of solar-like convection, carried out using the Anelastic Spherical Harmonic (ASH) code, that are designed to isolate those processes that drive and shape meridional circulations within stellar convection zones. These simulations have been constructed so as to span the transition between solar-like differential rotation (fast equator/slow poles) and ``anti-solar' differential rotation (slow equator/fast poles). Solar-like states of differential rotation, arising when convection is rotationally constrained, are characterized by a very different convective Reynolds stress than anti-solar regimes, wherein convection only weakly senses the Coriolis force. We find that the angular momentum transport by convective Reynolds stress plays a central role in establishing the meridional flow profiles in these simulations. We find that the transition from single-celled to multi-celled meridional circulation profiles in strong and weak regimes of rotational constraint is lin...

  9. Extension of Goldstein's circulation function for optimal rotors with hub

    Science.gov (United States)

    Okulov, V. L.; Sørensen, J. N.; Shen, W. Z.

    2016-09-01

    The aerodynamic interaction or interference between rotor blades and hub body is usually very complicated, but some useful simplifications can be made by considering the hub with an infinite cylinder. Various attempts to find the optimum distribution of circulation by the lifting vortex lines method have been previously proposed to describe the blade interaction with the hub modeled by the infinite cylinder. In this case, the ideal distribution of bound circulation on the rotor blades is such that the shed vortex system in the hub-area is a set of helicoidal vortex sheets moving uniformly as if rigid, exactly as in the case where there is no influence of the streamtube deformations by the central hub-body. In the present investigation, we consider a more specific problem of the rotor-hub interaction where the initial flow streamtubes and the rotor slipstream submitted strong deformations at the nose-area of the semi-infinite hub.

  10. Interactions between clouds and atmospheric circulation in the extratropics

    Science.gov (United States)

    Ceppi, Paulo

    In climate models, the simulation of clouds is known to be particularly problematic, leading to important biases in the climatological energy balance on regional scales, as well as to large uncertainties in the future amount of warming in response to greenhouse gas increase. This thesis explores the connections between clouds and atmospheric circulation in extratropical regions. In particular, we investigate the impacts of clouds and their uncertainties on atmospheric circulation and its response to global warming. We find that clouds have very substantial effects both on the mean circulation and on its future response to warming in climate models. In the mean state, the position of the midlatitude jet correlates well with the midlatitude shortwave cloud-radiative effect (SW CRE), which suffers from very large biases in models. Models in which midlatitude SW CRE is too negative have anomalously cold midlatitudes, leading to an anomalously equatorward jet position. This result is supported by idealized model experiments and appears consistent with the effect of midlatitude baroclinicity changes on eddy activity. This means that an accurate representation of clouds and their radiative effects is essential to correctly portray the mean circulation. In the context of greenhouse gas--forced change, we demonstrate that cloud-radiative changes have a surprisingly large impact on the atmospheric circulation response. This results mainly from the SW cloud feedback, whose specific spatial structure induces low-latitude warming and high-latitude cooling, enhancing midlatitude baroclinicity and favoring a strengthening and poleward shift of the midlatitude jet. This opposes the effects of other major feedbacks (e.g., the water vapor feedback and the longwave cloud feedback), which produce polar-amplified warming and weakened midlatitude baroclinicity. For this reason, cloud-radiative changes explain the majority of the poleward expansion of atmospheric circulation in our model

  11. Atmospheric Circulation of Hot Jupiters: Dayside-Nightside Temperature Differences

    CERN Document Server

    Komacek, Thaddeus D

    2016-01-01

    The full-phase infrared light curves of low-eccentricity hot Jupiters show a trend of increasing dayside-to-nightside brightness temperature difference with increasing equilibrium temperature. Here we present a three-dimensional model that explains this relationship, in order to shed insight on the processes that control heat redistribution in tidally-locked planetary atmospheres. This three-dimensional model combines predictive analytic theory for the atmospheric circulation and dayside-nightside temperature differences over a range of equilibrium temperature, atmospheric composition, and potential frictional drag strengths with numerical solutions of the circulation that verify this analytic theory. This analytic theory shows that the longitudinal propagation of waves mediates dayside-nightside temperature differences in hot Jupiter atmospheres, analogous to the wave adjustment mechanism that regulates the thermal structure in Earth's tropics. These waves can be damped in hot Jupiter atmospheres by either r...

  12. The k-Diameter of a Kind of Circulant Graph

    Institute of Scientific and Technical Information of China (English)

    ZHANG Xian-di

    2004-01-01

    The diameter of a graph G is the maximal distance between pairs of vertices of G. When a network is modeled as a graph,diameter is a measurement for maximum transmission delay. The k-diameter dk(G) of a graph G, which deals with k internally disjoint paths between pairs of vertices of G, is a extension of the diameter of G. It has widely studied in graph theory and computer science. The circulant graph is a group-theoretic model of a class of symmetric interconnection network. Let Cn(i, ) be a circulant graph of order n whose spanning elements are i and , where n≥4 and n is even. In this paper, the diameter, 2-diameter and 3-diameter of the Cn(i,) are all obtained if gcd(n,i)=1, where the symbol gcd(n,i) denotes the maximum common divisor of n and i.

  13. Numerical and Experimental Investigation of Circulation in Short Cylinders

    CERN Document Server

    Kageyama, A; Goodman, J; Chen, F; Shoshan, E; Kageyama, Akira; Ji, Hantao; Goodman, Jeremy; Chen, Fei; Shoshan, Ethan

    2004-01-01

    In preparation for an experimental study of magnetorotational instability (MRI) in liquid metal, we explore Couette flows having height comparable to the gap between cylinders, centrifugally stable rotation, and high Reynolds number. Experiments in water are compared with numerical simulations. Simulations show that endcaps corotating with the outer cylinder drive a strong poloidal circulation that redistributes angular momentum. Predicted azimuthal flow profiles agree well with experimental measurements. Spin-down times scale with Reynolds number as expected for laminar Ekman circulation; extrapolation from two-dimensional simulations at $Re\\le 3200$ agrees remarkably well with experiment at $Re\\sim 10^6$. This suggests that turbulence does not dominate the effective viscosity. Further detailed numerical studies reveal a strong radially inward flow near both endcaps. After turning vertically along the inner cylinder, these flows converge at the midplane and depart the boundary in a radial jet. To minimize th...

  14. Liquid Fluoride Salt Experimentation Using a Small Natural Circulation Cell

    Energy Technology Data Exchange (ETDEWEB)

    Yoder Jr, Graydon L [ORNL; Heatherly, Dennis Wayne [ORNL; Williams, David F [ORNL; Elkassabgi, Yousri M. [Texas A& M University, Kingsville; Caja, Joseph [Electrochemical Systems, Inc.; Caja, Mario [ORNL; Jordan, John [Texas A& M University, Kingsville; Salinas, Roberto [Texas A& M University, Kingsville

    2014-04-01

    A small molten fluoride salt experiment has been constructed and tested to develop experimental techniques for application in liquid fluoride salt systems. There were five major objectives in developing this test apparatus: Allow visual observation of the salt during testing (how can lighting be introduced, how can pictures be taken, what can be seen) Determine if IR photography can be used to examine components submerged in the salt Determine if the experimental configuration provides salt velocity sufficient for collection of corrosion data for future experimentation Determine if a laser Doppler velocimeter can be used to quantify salt velocities. Acquire natural circulation heat transfer data in fluoride salt at temperatures up to 700oC All of these objectives were successfully achieved during testing with the exception of the fourth: acquiring velocity data using the laser Doppler velocimeter. This paper describes the experiment and experimental techniques used, and presents data taken during natural circulation testing.

  15. Tacking bonds: fashion image circulation in social networks

    Directory of Open Access Journals (Sweden)

    Lívia Laura Matté

    2014-12-01

    Full Text Available This study aims at delineating the aspects of fashion in contemporary times under a bias of communication. It is a search to identify, through the images that circulate on social networks, the characteristics that may distinguish the contemporary fashion circumscribed to the so called postmodernity. Therefore, we performed a bibliographic research in order to understand the concepts of post modernity. Among the authors studied, we chose to follow the pathways taken by the French sociologist Michel Maffesoli, since his ideas about post modernity are the key to explain the contemporary fashion in post modernity. The corpus of this study consists of images extracted from a social network of fashion image sharing: Lookbook.nu: Collective Fashion Consciousness. We believe that these images are loaded with information that might explain fashion in post modernity, and contribute to discussions about the creation of bonds enabled by the circulation of these imagery elements.

  16. The prime factors of Wendt's binomial circulant determinant

    Science.gov (United States)

    Fee, Greg; Granville, Andrew

    1991-10-01

    Wendt's binomial circulant determinant, {W_m} , is the determinant of an m by m circulant matrix of integers, with (i, j)th entry ( {begin{array}{*{20}{c}} m {\\vert i - j\\vert} } ) whenever 2 divides m but 3 does not. We explain how we found the prime factors of {W_m} for each even m ≤ 200 by implementing a new method for computations in algebraic number fields that uses only modular arithmetic. As a consequence we prove that if p and q = mp + 1 are odd primes, 3 does not divide m, and m ≤ 200 , then the first case of Fermat's Last Theorem is true for exponent p.

  17. Culturable bacteria in Himalayan ice in response to atmospheric circulation

    Directory of Open Access Journals (Sweden)

    S. Zhang

    2006-06-01

    Full Text Available Only recently has specific attention been given to culturable bacteria in Tibetan glaciers, but their relation to atmospheric circulation is less understood yet. Here we investigate the seasonal variation of culturable bacteria preserved in a Himalayan ice core. High concentration of culturable bacteria in glacial ice deposited during the pre-monsoon season is attributed to the transportation of continental dust stirred up by the frequent dust storms in Northwest China during spring. This is also confirmed by the spatial distribution of culturable bacteria in Tibetan glaciers. Culturable bacteria deposited during monsoon season are more diverse than other seasons because they derive from both marine air masses and local or regional continental sources. We suggest that microorganisms in Himalayan ice can be used to reconstruct atmospheric circulation.

  18. Polymer grouts for plugging lost circulation in geothermal wells.

    Energy Technology Data Exchange (ETDEWEB)

    Galbreath, D. (Green Mountain International, Waynesvile, NC); Mansure, Arthur James; Bauer, Stephen J.

    2004-12-01

    We have concluded a laboratory study to evaluate the survival potential of polymeric materials used for lost circulation plugs in geothermal wells. We learned early in the study that these materials were susceptible to hydrolysis. Through a systematic program in which many potential chemical combinations were evaluated, polymers were developed which tolerated hydrolysis for eight weeks at 500 F. The polymers also met material, handling, cost, and emplacement criteria. This screening process identified the most promising materials. A benefit of this work is that the components of the polymers developed can be mixed at the surface and pumped downhole through a single hose. Further strength testing is required to determine precisely the maximum temperature at which extrusion through fractures or voids causes failure of the lost circulation plug.

  19. Hybrid Palliation for Ductal-Dependent Systemic Circulation.

    Science.gov (United States)

    Evans, William N; Galindo, Alvaro; Rothman, Abraham; Ciccolo, Michael L; Carrillo, Sergio A; Acherman, Ruben J; Mayman, Gary A; Cass, Kathleen A; Kip, Katrinka T; Luna, Carlos F; Ludwick, Joseph M; Rollins, Robert C; Castillo, William J; Alexander, John A; Restrepo, Humberto

    2016-06-01

    We reviewed our hybrid palliation experience for 91 neonates, with ductal-dependent systemic circulation, born between August 2007 and October 2015. For analysis, we stratified the 91 patients by a risk factor (RF) score and divided them into three groups: (1) high-risk two-functional ventricles (2V) median RF score of 3 (N = 20); (2) low-risk one-functional ventricle (1V) RF score 0-1 (N = 32); and (3) high-risk 1V RF score ≥2 (N = 39). Midterm survival (median 4 years) by group was: (1) 95 %, (2) 91 %, and (3) 15 %, (p = 0.001). In conclusion, hybrid palliation was associated with excellent midterm results for high-risk 2V and low-risk 1V patients with ductal-dependent systemic circulation. In contrast, high-risk 1V patients had significantly worse outcomes.

  20. Flow Regimes of Mesoscale Circulations Forced by Inhomogeneous Surface Heating

    CERN Document Server

    Hossain, M Alamgir

    2016-01-01

    Urbanization is one of the extreme process that increases uncertainty in future climate projections. Flow regimes of mesoscale circulations associated with surface heating due to urbanization have been investigated using a wavelet based computational fluid dynamics~(CFD) model. The results of our numerical model have been validated against that of a laboratory model, as well as reference numerical simulations. Characteristics of urban induced circulations have been studied for surface heat flux perturbation ($H_0$) between $28.93$Wm$^{-2}$ and $925.92$Wm$^{-2}$, and the results have been analyzed against available boundary layer measurements under similar physical conditions. Our primary study shows that urban/rural heat flux anomalies introduce strong oscillations in the convective boundary layer (CBL), and transfers a fraction of the turbulent kinetic energy vertically through internal waves. Such results complement previous investigators' hypothesis that temporal oscillations in urban-induced mesoscale cir...

  1. The existence and stability of steady circulations in a conditionally symmetrically unstable basic flow

    Science.gov (United States)

    Xu, Qin

    1987-01-01

    The existence of steady, nonlinear circulations in a flow susceptible to conditionally symmetric instability is studied, treating the latent heating as an energy source which is implicitly related to the motion field. The viscous nonlinear circulations of symmetrical instability are briefly discussed, and an existence theorem for steady, nonlinear symmetric circulations with bounded rates of latent heat release is given. The uniqueness and stability of these circulations are discussed, and some physical interpretations are given.

  2. Isomorphic Operators and Functional Equations for the Skew-Circulant Algebra

    Directory of Open Access Journals (Sweden)

    Zhaolin Jiang

    2014-01-01

    Full Text Available The skew-circulant matrix has been used in solving ordinary differential equations. We prove that the set of skew-circulants with complex entries has an idempotent basis. On that basis, a skew-cyclic group of automorphisms and functional equations on the skew-circulant algebra is introduced. And different operators on linear vector space that are isomorphic to the algebra of n×n complex skew-circulant matrices are displayed in this paper.

  3. The mean meridional circulation and midlatitude ozone buildup

    Directory of Open Access Journals (Sweden)

    G. Nikulin

    2005-06-01

    Full Text Available The development of wintertime ozone buildup over the Northern Hemisphere (NH midlatitudes and its connection with the mean meridional circulation in the stratosphere are examined statistically on a monthly basis from October to March (1980–2002. The ozone buildup begins locally in October with positive ozone tendencies over the North Pacific, which spread eastward and westward in November and finally cover all midlatitudes in December. During October–January a longitudinal distribution of the ozone tendencies mirrors a structure of quasi-stationary planetary waves in the lower stratosphere and has less similarity with this structure in February–March when chemistry begins to play a more important role. From November to March, zonal mean ozone tendencies (50°–60° N show strong correlation (|r|=0.7 with different parameters used as proxies of the mean meridional circulation, namely: eddy heat flux, the vertical residual velocity (diabatically-derived and temperature tendency. The correlation patterns between ozone tendency and the vertical residual velocity or temperature tendency are more homogeneous from month to month than ones for eddy heat flux. A partial exception is December when correlation is strong only for the vertical residual velocity. In October zonal mean ozone tendencies have no coupling with the proxies. However, positive tendencies averaged over the North Pacific correlate well, with all of them suggesting that intensification of northward ozone transport starts locally over the Pacific already in October. We show that the NH midlatitude ozone buildup has stable statistical relation with the mean meridional circulation in all months from October to March and half of the interannual variability in monthly ozone tendencies can be explained by applying different proxies of the mean meridional circulation.

  4. Experimental studies toward the characterization of Inmetro's circulating water channel

    Science.gov (United States)

    Santos, A. M.; Alho, A. T. P.; Garcia, D. A.; Farias, M. H.; Massari, P. L.; Silva, V. V. S.

    2016-07-01

    Circulating water channels are facilities which can be used for conducting environmental, metrological and engineering studies. The Brazilian National Institute of Metrology-INMETRO has a water channel of innovative design, and the present work deals with the prior experimental investigation of its hydrodynamics performance. By using the optical technique PIV - Particle Image Velocimetry, under certain conditions, the velocity profile behavior in a region inside the channel was analyzed in order to evaluate the scope of applicability of such bench.

  5. 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.

  6. Experimental and calculated calibration of ionization chambers with air circulation

    CERN Document Server

    Peetermans, A

    1972-01-01

    The reports describes the method followed in order to calibrate the different ionization chambers with air circulation, used by the 'Health Physics Group'. The calculations agree more precisely with isotopes cited previously (/sup 11/C, /sup 13/N, /sup 15/O, /sup 41 /Ar, /sup 14/O, /sup 38/Cl) as well as for /sup 85/Kr, /sup 133/Xe, /sup 14/C and tritium which are used for the experimental standardisation of different chambers.

  7. Coastal Ocean Circulation Experiment off Senegal (COCES - II)

    Science.gov (United States)

    2013-09-30

    1 DISTRIBUTION STATEMENT A. Approved for public release; distribution is unlimited. Coastal Ocean Circulation Experiment off Senegal (COCES...particular emphasis on eddy dynamics. OBJECTIVES The general objective of COCES-II is to investigate the coastal dynamics off the coast of Senegal , a...Senegalese scientists to study the North Atlantic off the west African coast. APPROACH Surface drifters are deployed off the coast of Senegal on a

  8. Circulant conference matrices for new complex Hadamard matrices

    OpenAIRE

    Dita, Petre

    2011-01-01

    The circulant real and complex matrices are used to find new real and complex conference matrices. With them we construct Sylvester inverse orthogonal matrices by doubling the size of inverse complex conference matrices. When the free parameters take values on the unit circle the inverse orthogonal matrices transform into complex Hadamard matrices. The method is used for $n=6$ conference matrices and in this way we find new parametrisations of Hadamard matrices for dimension $ n=12$.

  9. The impact of oceanic heat transport on the atmospheric circulation

    Directory of Open Access Journals (Sweden)

    M.-A. Knietzsch

    2014-11-01

    Full Text Available A general circulation model of intermediate complexity with an idealized earthlike aquaplanet setup is used to study the impact of changes in the oceanic heat transport on the global atmospheric circulation. Focus is put on the Lorenz energy cycle and the atmospheric mean meridional circulation. The latter is analysed by means of the Kuo–Eliassen equation. The atmospheric heat transport compensates the imposed oceanic heat transport changes to a large extent in conjunction with significant modification of the general circulation. Up to a maximum about 3 PW, an increase of the oceanic heat transport leads to an increase of the global mean near-surface temperature and a decrease of its equator-to-pole gradient. For larger transports, the gradient is reduced further but the global mean remains approximately constant. This is linked to a cooling and a reversal of the temperature gradient in the tropics. A larger oceanic heat transport leads to a reduction of all reservoirs and conversions of the Lorenz energy cycle but of different relative magnitude for the individual components. The available potential energy of the zonal mean flow and its conversion to eddy available potential energy are affected most. Both the Hadley and Ferrel cell show a decline for increasing oceanic heat transport, with the Hadley cell being more sensitive. Both cells exhibit a poleward shift of their maxima, and the Hadley cell broadens for larger oceanic transports. The partitioning, by means of the Kuo–Eliassen equation, reveals that zonal mean diabatic heating and friction are the most important sources for changes of the Hadley cell, while the behaviour of the Ferrell cell is mostly controlled by friction.

  10. 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.

  11. Increased circulating calcitonin gene-related peptide (CGRP) in cirrhosis

    DEFF Research Database (Denmark)

    Bendtsen, Flemming; Schifter, S; Henriksen, Jens Henrik

    1991-01-01

    with minor disorders (59 vs. 46 pmol/l, p less than 0.01), as well as with 232 healthy persons (37 pmol/l, p less than 0.0001). Moreover, circulating CGRP increased significantly with the severity of cirrhosis (Child-Turcotte group A, 56; group B, 59; group C, 71 pmol/l; p less than 0.025). No significant...

  12. NUCLA Circulating Atmospheric Fluidized Bed Demonstration Project. 1990 Annual report

    Energy Technology Data Exchange (ETDEWEB)

    1992-02-01

    The objective of this DOE Cooperative Agreement is to conduct a cost-shared clean coal technology project to demonstrate the feasibility of circulating fluidized bed combustion technology and to evaluate economic, environmental, and operational benefits of CFB steam generators on a utility scale. At the conclusion of the Phase 2 program, testing related to satisfying these objectives was completed. Data analysis and reporting are scheduled for completion by October 1991. (VC)

  13. Hyperintense Acute Reperfusion Marker on FLAIR in Posterior Circulation Infarction.

    Directory of Open Access Journals (Sweden)

    Alex Förster

    Full Text Available In the present study, we aimed to investigate the frequency of blood brain barrier injury in posterior circulation infarction as demonstrated by the hyperintense acute reperfusion marker (HARM on fluid attenuated inversion recovery images (FLAIR.From a MRI report database we identified patients with posterior circulation infarction who underwent MRI, including perfusion-weighted images (PWI, within 12 hours after onset and follow-up MRI within 24 hours and analyzed diffusion-weighted images (DWI, PWI, FLAIR, and MR angiography (MRA. On FLAIR images, the presence of HARM was noted by using pre-specified criteria (focal enhancement in the subarachnoid space and/or the ventricles.Overall 16 patients (median age of patients 68.5 (IQR 55.5-82.75 years with posterior circulation infarction were included. Of these, 13 (81.3% demonstrated PCA occlusion, and 3 (18.7% patients BA occlusion on MRA. Initial DWI demonstrated ischemic lesions in the thalamus (68.8%, splenium (18.8%, hippocampus (75%, occipital lobe (81.3%, mesencephalon (18.8%, pons (18.8%, and cerebellum (50%. On follow-up MRA recanalization was noted in 10 (62.5% patients. On follow-up FLAIR images, HARM was observed in 8 (50% patients. In all of these, HARM was detected remote from the acute ischemic lesion. HARM was more frequently observed in patients with vessel recanalization (p = 0.04, minor infarction growth (p = 0.01, and smaller ischemic lesions on follow-up DWI (p = 0.05.HARM is a frequent finding in posterior circulation infarction and associated with vessel recanalization, minor infarction growth as well as smaller infarction volumes in the course. Neuroradiologists should be cognizant of the fact that HARM may be present on short interval follow-up FLAIR images in patients with acute ischemic infarction who initially underwent MRI and received intravenous gadolinium-based contrast agents.

  14. Assessment of Radiation Risk by Circulating microRNAs

    Science.gov (United States)

    Wang, Jufang

    2016-07-01

    Highly energized particles delivered by galactic cosmic rays as well as solar particle events are one of the most severe detrimental factors to the health of crews during long-term space missions. Researches related to the assessment of radiation risk have been carried out with ground-based accelerator facilities all around the world. Circulating microRNAs (miRNAs) in blood have the advantages of specificity and stability, which could be used as disease biomarkers and potential bio-dosimeters to monitor the radiation risk. Based on this backgroud, circulating miRNAs were isolated from blood after Kunming mice were whole-body exposed to 300MeV/u carbon ion beam which were generated by the Heavy Ion Research Facility in Lanzhou (HIRFL), and the levels of miRNA expression were detected by miRNA PCR array. It was found that more than one hundred of circulating miRNAs were responded to carbon ion irradiation. Among these radiosensitive miRNAs, most of them were closely associated with immune system and hematopoietic system. The miRNA levels changed more than 2-fold were further verified by qRT-PCR analysis following exposure to X rays and iron ion beam. Some miRNAs such as let-7a, miR-34a, miR-223 and miR-150 showed obvious radio-sensitivity and dose-dependent effect, demonstrating that they were potential biomarkers of radiation and could be used as ideal bio-dosimeters. Those findings indicate that with the properties of high radio-sensitivity and time-saving quantification method by standard PCR assay, circulating miRNAs may become potential biomarkers for radiation detection in space exploration.

  15. Identification of distinct circulating exosomes in Parkinson’s disease

    OpenAIRE

    Tomlinson, PR; Zheng, Y.; Fischer, R.; Heidasch, R.; Gardiner, C; Evetts, S.; Hu, M.; Wade-Martins, R.; Turner; Morris, J; Talbot, K; Kessler, BM; Tofaris, GK

    2015-01-01

    Objective: Whether circulating microvesicles convey bioactive signals in neurodegenerative diseases remains currently unknown. In this study, we investigated the biochemical composition and biological function of exosomes isolated from sera of patients with Parkinson’s disease (PD). Methods: Proteomic analysis was performed on microvesicle preparations from grouped samples of patients with genetic and sporadic forms of PD, amyotrophic lateral sclerosis, and healthy subjects. Nanoparticle-t...

  16. Elevated circulating plasma endothelin-1 concentrations in cirrhosis

    DEFF Research Database (Denmark)

    Møller, Søren; Emmeluth, C; Henriksen, Jens Henrik

    1993-01-01

    veins on the one hand and the femoral artery on the other (P > 0.1), indicating no major net elimination or release in the liver, kidney or lower limb. A significant negative correlation was found between systolic and diastolic blood pressures on the one hand and circulating ET-1 on the other (r = -0.......70, P vein catheterization (n = 8), no significant differences were found in ET-1 plasma concentration between the liver, renal, or femoral...

  17. The challenges of detecting circulating tumour cells in sarcoma

    OpenAIRE

    Tellez-Gabriel, M.; Brown, H K; Young, R.; Heymann, M. F.; Heymann, D

    2016-01-01

    International audience; Sarcomas are a heterogenous group of malignant neoplasms of mesenchymal origin, many of which have a propensity to develop distant metastases. Cancer cells that have escaped from the primary tumour are able to invade into surrounding tissues, to intravasate into the bloodstream to become Circulating Tumour Cells (CTCs), and are responsible for the generation of distant metastases. Due to the rarity of these tumours and the absence of specific markers expressed by sarco...

  18. 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.

  19. The beam has circulated 30 minutes in the LHC!

    CERN Multimedia

    Last night around 2 a.m. the beam circulated for the first time for about 30 minutes in the clockwise ring of the LHC. This confirms that the accelerating cavities are working well. During the night, the LHC team also increased the intensity of the single bunch to around 1/20th of the nominal LHC bunch intensity. You can follow the beam commissioning daily reports on: https://lhc-commissioning.web.cern.ch/lhc-commissioning/dailynews/index.htm

  20. Amphiphilic vinyl polymers effectively prolong liposome circulation time in vivo.

    Science.gov (United States)

    Torchilin, V P; Shtilman, M I; Trubetskoy, V S; Whiteman, K; Milstein, A M

    1994-10-12

    Newly synthesized amphiphilic polyacrylamide and poly(vinyl pyrrolidone), single terminus-modified with long-chain fatty acyl groups, are able to incorporate into the liposomal membrane, and similar to poly(ethylene glycol) prolong liposome circulation in vivo and decrease liposome accumulation in the liver. Protective efficacy of modified polymers increases with the increase in the length of acyl moiety and decreases for higher molecular weight polymers. The data on amphiphilic polymer-modified liposome biodistribution are presented.

  1. A review of existing gas-cooled reactor circulators with application of the lessons learned to the new production reactor circulators

    Energy Technology Data Exchange (ETDEWEB)

    White, L.S.

    1990-07-01

    This report presents the results of a study of the lessons learned during the design, testing, and operation of gas-cooled reactor coolant circulators. The intent of this study is to identify failure modes and problem areas of the existing circulators so this information can be incorporated into the design of the circulators for the New Production Reactor (NPR)-Modular High-Temperature Gas Cooled Reactor (MHTGR). The information for this study was obtained primarily from open literature and includes data on high-pressure, high-temperature helium test loop circulators as well as the existing gas cooled reactors worldwide. This investigation indicates that trouble free circulator performance can only be expected when the design program includes a comprehensive prototypical test program, with the results of this test program factored into the final circulator design. 43 refs., 7 tabs.

  2. Circulation of core collection monographs in an academic medical library.

    Science.gov (United States)

    Schmidt, C M; Eckerman, N L

    2001-04-01

    Academic medical librarians responsible for monograph acquisition face a challenging task. From the plethora of medical monographs published each year, academic medical librarians must select those most useful to their patrons. Unfortunately, none of the selection tools available to medical librarians are specifically intended to assist academic librarians with medical monograph selection. The few short core collection lists that are available are intended for use in the small hospital or internal medicine department library. As these are the only selection tools available, however, many academic medical librarians spend considerable time reviewing these collection lists and place heavy emphasis on the acquisition of listed books. The study reported here was initiated to determine whether the circulation of listed books in an academic library justified the emphasis placed on the acquisition of these books. Circulation statistics for "listed" and "nonlisted" books in the hematology (WH) section of Indiana University School of Medicine's Ruth Lilly Medical Library were studied. The average circulation figures for listed books were nearly two times as high as the corresponding figures for the WH books in general. These data support the policies of those academic medical libraries that place a high priority on collection of listed books.

  3. Circulating microRNAs as Potential Biomarkers of Infectious Disease

    Science.gov (United States)

    Correia, Carolina N.; Nalpas, Nicolas C.; McLoughlin, Kirsten E.; Browne, John A.; Gordon, Stephen V.; MacHugh, David E.; Shaughnessy, Ronan G.

    2017-01-01

    microRNAs (miRNAs) are a class of small non-coding endogenous RNA molecules that regulate a wide range of biological processes by post-transcriptionally regulating gene expression. Thousands of these molecules have been discovered to date, and multiple miRNAs have been shown to coordinately fine-tune cellular processes key to organismal development, homeostasis, neurobiology, immunobiology, and control of infection. The fundamental regulatory role of miRNAs in a variety of biological processes suggests that differential expression of these transcripts may be exploited as a novel source of molecular biomarkers for many different disease pathologies or abnormalities. This has been emphasized by the recent discovery of remarkably stable miRNAs in mammalian biofluids, which may originate from intracellular processes elsewhere in the body. The potential of circulating miRNAs as biomarkers of disease has mainly been demonstrated for various types of cancer. More recently, however, attention has focused on the use of circulating miRNAs as diagnostic/prognostic biomarkers of infectious disease; for example, human tuberculosis caused by infection with Mycobacterium tuberculosis, sepsis caused by multiple infectious agents, and viral hepatitis. Here, we review these developments and discuss prospects and challenges for translating circulating miRNA into novel diagnostics for infectious disease. PMID:28261201

  4. Cold-Flow Circulating Fluidized-Bed Identification

    Energy Technology Data Exchange (ETDEWEB)

    Parviz Famouri

    2005-07-01

    In a variety of industrial applications, the use of a circulating fluidized bed (CFB) provides various advantages, such as reducing environmental pollution and increasing process efficiency. The application of circulating fluidized bed technology contributes to the improvement of gas-solid contact, reduction of the cross-sectional area with the use of higher superficial velocities, the use of the solids circulation rate as an additional control variable, and superior radial mixing, Grace et al. [1]. In order to improve raw material usage and utility consumption, optimization and control of CFB is very important, and an accurate, real time model is required to describe and quantify the process. Currently there is no accepted way to construct a reliable model for such a complex CFB system using traditional methods, especially at the pilot or industrial scale. Three major obstacles in characterizing the system are: 1) chaotic nature of the system; 2) non-linearity of the system, and 3) number of immeasurable unknowns internal to the system,[2]. Advanced control theories and methods have the ability to characterize the system, and can overcome all three of these obstacles. These methods will be discussed in this report.

  5. Perfect state transfer, integral circulants and join of graphs

    CERN Document Server

    Angeles-Canul, Ricardo Javier; Opperman, Michael C; Paribello, Christopher C; Russell, Matthew C; Tamon, Christino

    2009-01-01

    We propose new families of graphs which exhibit quantum perfect state transfer. Our constructions are based on the join operator on graphs, its circulant generalizations, and the Cartesian product of graphs. We build upon the results of Ba\\v{s}i\\'{c} et al \\cite{bps09,bp09} and construct new integral circulants and regular graphs with perfect state transfer. More specifically, we show that the integral circulant $\\textsc{ICG}_{n}(\\{2,n/2^{b}\\} \\cup Q)$ has perfect state transfer, where $b \\in \\{1,2\\}$, $n$ is a multiple of 16 and $Q$ is a subset of the odd divisors of $n$. Using the standard join of graphs, we also show a family of double-cone graphs which are non-periodic but exhibit perfect state transfer. This class of graphs is constructed by simply taking the join of the empty two-vertex graph with a specific class of regular graphs. This answers a question posed by Godsil \\cite{godsil08}.

  6. A Note on the South China Sea Shallow Interocean Circulation

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    The existing estimates of the volume transport from the Pacific Ocean to the South China Sea are summarized, showing an annual mean westward transport, with the Taiwan Strait outflow subtracted, of 3.5±2.0 Sv (1 Sv=106 m3 s-1). Results of a global ocean circulation model show an annual mean transport of 3.9 Sv from the Pacific to the Indian Ocean through the South China Sea. The boreal winter transport is larger and exhibits a South China Sea branch of the Pacific-to-Indian Ocean throughflow, which originates from the western Philippine Sea toward the Indonesian Seas through the South China Sea, as well as through the Karimata and Mindoro Straits. The southwestward current near the continental slope of the northern South China Sea is shown to be a combination of this branch and the interior circulation gyre.This winter branch can be confirmed by trajectories of satellite-tracked drifters, which clearly show a flow from the Luz6n Strait to the Karimata Strait in winter. In summer, the flow in the Karimata Strait is reversed. Numerical model results indicate that the Pacific water can enter the South China Sea and exit toward the Sulu Sea, but no observational evidence is available. The roles of the throughflow branch in the circulation, water properties and air-sea exchange of the South China Sea, and in enhancing and regulating the volume transport and reducing the heat transport of the Indonesian Throughflow, are discussed.

  7. Higher-order graph wavelets and sparsity on circulant graphs

    Science.gov (United States)

    Kotzagiannidis, Madeleine S.; Dragotti, Pier Luigi

    2015-08-01

    The notion of a graph wavelet gives rise to more advanced processing of data on graphs due to its ability to operate in a localized manner, across newly arising data-dependency structures, with respect to the graph signal and underlying graph structure, thereby taking into consideration the inherent geometry of the data. In this work, we tackle the problem of creating graph wavelet filterbanks on circulant graphs for a sparse representation of certain classes of graph signals. The underlying graph can hereby be data-driven as well as fixed, for applications including image processing and social network theory, whereby clusters can be modelled as circulant graphs, respectively. We present a set of novel graph wavelet filter-bank constructions, which annihilate higher-order polynomial graph signals (up to a border effect) defined on the vertices of undirected, circulant graphs, and are localised in the vertex domain. We give preliminary results on their performance for non-linear graph signal approximation and denoising. Furthermore, we provide extensions to our previously developed segmentation-inspired graph wavelet framework for non-linear image approximation, by incorporating notions of smoothness and vanishing moments, which further improve performance compared to traditional methods.

  8. Role of endothelin in uteroplacental circulation and fetal vascular function.

    Science.gov (United States)

    Paradis, Alexandra; Zhang, Lubo

    2013-09-01

    Endothelins are 21-amino acid peptides involved in vascular homeostasis. Three types of peptide have been identified, with endothelin-1 (ET-1) being the most potent vasoconstrictor currently known. Two endothelin receptor subtypes are found in various tissues, including the brain, heart, blood vessel, lung, and placenta. The ETA-receptor is associated with vasoconstriction in vascular smooth muscle. Conversely, the ETB-receptor can elicit a vasoconstrictor effect in vascular smooth muscle and a vasodilator effect via its action in endothelial cells. Both receptors play a key role in maintaining circulatory homeostasis and vascular function. Changes in ET-1 expression are found in various disease states, and overexpression of ET-1 is observed in hypertension and preeclampsia in pregnancy. Placental localization of ET-1 implies a key role in regulating the uteroplacental circulation. Additionally, ET-1 is important in the fetal circulation and is involved in the pulmonary circulation and closure of the ductus arteriosus after birth, as well as fetal growth constriction in utero. ET receptor antagonists and nitric oxide donors may provide therapeutic potential in treating conditions associated with overexpression of ET and hypertension.

  9. Uteroplacental circulation and fetal vascular function and development.

    Science.gov (United States)

    Thornburg, Kent L; Louey, Samantha

    2013-09-01

    Although blood flow in the placental vasculature is governed by the same physiological forces of shear, pressure and resistance as in other organs, it is also uniquely specialized on the maternal and fetal sides. At the materno-fetal interface, the independent uteroplacental and umbilicoplacental circulations must coordinate sufficiently to supply the fetus with the nutrients and substrates it needs to grow and develop. Uterine arterial flow must increase dramatically to accommodate the growing fetus. Recent evidence delineates the hormonal and endothelial mechanisms by which maternal vessels dilate and remodel during pregnancy. The umbilical circulation is established de novo during embryonic development but blood does not flow through the placenta until late in the first trimester. The umbilical circulation operates in the interest of maintaining fetal oxygenation over the course of pregnancy, and is affected differently by mechanical and chemical regulators of vascular tone compared to other organs. The processes that match placental vascular growth and fetal tissue growth are not understood, but studies of compromised pregnancies provide clues. The subtle changes that cause the failure of the normally regulated vascular processes during pregnancy have not been thoroughly identified. Likewise, practical and effective therapeutic strategies to reverse detrimental placental perfusion patterns have yet to be investigated.

  10. Fetal cerebrovascular circulation: a review of prenatal ultrasound assessment.

    Science.gov (United States)

    Degani, S

    2008-01-01

    Antenatal intrauterine cerebrovascular events were found to play an important role in the pathogenesis of perinatal brain damage. Changes in placental vascular resistance, cardiac contractibility, vessel compliance, and blood viscosity alter the normal dynamics of fetal cerebral circulation. The circulatory mechanisms described in animal fetuses also operate in the human fetus. The isthmus of the aorta represents a watershed area reflecting the redistribution of blood during increased peripheral resistance and hypoxia. The fetal cerebrovascular system acts locally within the skull and interacts with the other components of fetal circulation to compensate by redistribution of blood in case of shortage in resources. The introduction of various sonographic techniques and the collection of data from the arterial and venous cerebral circulation have improved our understanding of the regulatory mechanisms involved in fetal cerebral hemodynamic events. Anatomical and physiological considerations of cerebral vasculature in health and disease are relevant in the research of variations in fetal brain blood perfusion. Changes in flow characteristics in fetal cerebral vasculature can be used for clinical decisions. However, caution is advised before applying research data into practice. The clinical utility is well established in situations of fetal compromise such as growth restriction and anemia.

  11. Oxidative stress and antioxidant status in fetal circulation in preeclampsia.

    Science.gov (United States)

    Braekke, Kristin; Harsem, Nina K; Staff, Anne C

    2006-11-01

    Preeclampsia is associated with oxidative stress in maternal circulation. The purpose of this study was to explore oxidative stress and antioxidants in the fetal circulation in preeclampsia. Women with preeclampsia (n = 19) or uncomplicated pregnancies (n = 33) delivered by cesarean section were included. Blood was sampled separately from the umbilical vein and artery. 8-Iso-prostaglandin F(2alpha) (8-isoprostane), a stable product of lipid peroxidation, is a reliable marker of oxidative stress. Concentration of total 8-isoprostane in cord plasma was analyzed by gas chromatography-mass spectrometry. Antioxidant status was evaluated measuring ferric reducing ability of plasma and vitamin E. There was no difference between preeclampsia and control groups regarding median plasma concentration of 8-isoprostane in umbilical vein (955 versus 780 pg/mL, p = 0.41) or in umbilical artery (233 versus 276 pg/mL, p = 0.65). Concentration of 8-isoprostane was much higher in plasma from the umbilical vein than artery, suggesting placenta as the source of 8-isoprostane. Median ferric reducing ability of plasma concentration was higher in preeclampsia than in controls, both in the umbilical vein and artery. Median vitamin E concentration in the umbilical vein was higher in preeclampsia, but no difference was found in the umbilical artery. In conclusion, no evidence of increased oxidative stress, evaluated by 8-isoprostane concentration, was found in fetal circulation in preeclampsia.

  12. 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.

  13. Circulating MicroRNAs and Life Expectancy Among Identical Twins.

    Science.gov (United States)

    Wu, Shenghui; Kim, Taek-Kyun; Wu, Xiaogang; Scherler, Kelsey; Baxter, David; Wang, Kai; Krasnow, Ruth E; Reed, Terry; Dai, Jun

    2016-09-01

    Human life expectancy is influenced not only by longevity assurance mechanisms and disease susceptibility loci but also by the environment, gene-environment interactions, and chance. MicroRNAs (miRNAs) are a class of small noncoding RNAs closely related to genes. Circulating miRNAs have been shown as promising noninvasive biomarkers in the development of many pathophysiological conditions. However, the concentration of miRNA in the circulation may also be affected by environmental factors. We used a next-generation sequencing platform to assess the association of circulating miRNA with life expectancy, for which deaths are due to all causes independent of genes. In addition, we showed that miRNAs are present in 41-year archived plasma samples, which may be useful for both life expectancy and all-cause mortality risk assessment. Plasma miRNAs from nine identical male twins were profiled using next-generation sequencing. The average absolute difference in the minimum life expectancy was 9.68 years. Intraclass correlation coefficients were above 0.4 for 50% of miRNAs. Comparing deceased twins with their alive co-twin brothers, the concentrations were increased for 34 but decreased for 30 miRNAs. Identical twins discordant in life expectancy were dissimilar in the majority of miRNAs, suggesting that environmental factors are pivotal in miRNAs related to life expectancy.

  14. The relationship between the thermohaline circulation and climate variability

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The long-term integration with the Global Ocean-Atmosphere-Land System model of the State Key Laboratory of Atmospheric Sciences and Geophysical Fluid Dynamics (LASG), Institute of Atmospheric Physics(IAP), Chinese Academy of Sciences has been used in the investigations on the relationship between the thermohaline circulation and climate variability. The results show that the strength of the North Atlantic Thermohaline circulation (THC) is negatively correlated with the North Atlantic Oscillation (NAO). Based on this kind of relationship, and also the instrument-measured climate record such as air pressure and sea surface temperature, the activity of the thermohaline circulation during the 20th century has been evaluated. The inferred variations of the strength of the THC is that, during two multi-decadal periods of 1867-1903 and 1934-1972, the THC is estimated to have been running stronger, whereas during the two periods of 1904-1933 and 1973-1994, it appears to have been weaker.

  15. Photoacoustic imaging of single circulating melanoma cells in vivo

    Science.gov (United States)

    Wang, Lidai; Yao, Junjie; Zhang, Ruiying; Xu, Song; Li, Guo; Zou, Jun; Wang, Lihong V.

    2015-03-01

    Melanoma, one of the most common types of skin cancer, has a high mortality rate, mainly due to a high propensity for tumor metastasis. The presence of circulating tumor cells (CTCs) is a potential predictor for metastasis. Label-free imaging of single circulating melanoma cells in vivo provides rich information on tumor progress. Here we present photoacoustic microscopy of single melanoma cells in living animals. We used a fast-scanning optical-resolution photoacoustic microscope to image the microvasculature in mouse ears. The imaging system has sub-cellular spatial resolution and works in reflection mode. A fast-scanning mirror allows the system to acquire fast volumetric images over a large field of view. A 500-kHz pulsed laser was used to image blood and CTCs. Single circulating melanoma cells were imaged in both capillaries and trunk vessels in living animals. These high-resolution images may be used in early detection of CTCs with potentially high sensitivity. In addition, this technique enables in vivo study of tumor cell extravasation from a primary tumor, which addresses an urgent pre-clinical need.

  16. Serologic evidence of human metapneumovirus circulation in Uruguay

    Directory of Open Access Journals (Sweden)

    Santiago Mirazo

    2005-11-01

    Full Text Available First identified in 2001, the human metapneumovirus (hMPV, is a respiratory tract pathogen that affects young children, elderly, and immunocompromised patients. The present work represents the first serologic study carried out in Uruguay. It was performed with the purpose of obtaining serological evidence of hMPV circulation in Uruguay and to contribute to the few serologic reports described until now. Sixty nine serum samples collected between 1998 and 2001 by vein puncture from patients without respiratory symptoms or underlying pathology aged 6 days to 60 years were examined using an indirect immunofluorescence assay (IFA. The global seropositivity rate of the samples was 80% (55/69. Rates of 60% (15/25 and 91% (40/44 were observed for the pediatric and adult cohorts, respectively. Results obtained from a longitudinal analysis of 6 children aged 6 days to 18 months are discussed. These results are a clear evidence of hMPV circulation in Uruguay, at least since 1998, and reinforce the previous data on worldwide circulation of this virus.

  17. Shear-Driven Circulation Patterns in Lipid Membrane Vesicles

    CERN Document Server

    Woodhouse, Francis G; 10.1017/jfm.2012.118

    2012-01-01

    Recent experiments have shown that when a near-hemispherical lipid vesicle attached to a solid surface is subjected to a simple shear flow it exhibits a pattern of membrane circulation much like a dipole vortex. This is in marked contrast to the toroidal circulation that would occur in the related problem of a drop of immiscible fluid attached to a surface and subjected to shear. This profound difference in flow patterns arises from the lateral incompressibility of the membrane, which restricts the observable flows to those in which the velocity field in the membrane is two-dimensionally divergence free. Here we study these circulation patterns within the simplest model of membrane fluid dynamics. A systematic expansion of the flow field based on Papkovich--Neuber potentials is developed for general viscosity ratios between the membrane and the surrounding fluids. Comparison with experimental results [C. V\\'ezy, G. Massiera, and A. Viallat, Soft Matter 3, 844 (2007)] is made, and it is shown how such studies ...

  18. Circulating Mitochondrial DAMPs Cause Inflammatory Responses to Injury

    Science.gov (United States)

    Zhang, Qin; Raoof, Mustafa; Chen, Yu; Sumi, Yuka; Sursal, Tolga; Junger, Wolfgang; Brohi, Karim; Itagaki, Kiyoshi; Hauser, Carl J.

    2009-01-01

    Injury causes a systemic inflammatory response syndrome (SIRS) clinically much like sepsis 1. Microbial pathogen-associated molecular patterns (PAMPs) activate innate immunocytes through pattern recognition receptors 2. Similarly, cellular injury can release endogenous damage-associated molecular patterns (DAMPs) that activate innate immunity 3. Mitochondria are evolutionary endosymbionts that were derived from bacteria 4 and so might bear bacterial molecular motifs. We show here that injury releases mitochondrial DAMPs (MTD) into the circulation with functionally important immune consequences. MTD include formyl peptides and mitochondrial DNA. These activate human neutrophils (PMN) through formyl peptide receptor-1 and TLR9 respectively. MTD promote PMN Ca2+ flux and phosphorylation of MAP kinases, thus leading to PMN migration and degranulation in vitro and in vivo. Circulating MTD can elicit neutrophil-mediated organ injury. Cellular disruption by trauma releases mitochondrial DAMPs with evolutionarily conserved similarities to bacterial PAMPs into the circulation. These can then signal through identical innate immune pathways to create a sepsis-like state. The release of such mitochondrial ‘enemies within’ by cellular injury is a key link between trauma, inflammation and SIRS. PMID:20203610

  19. Role of Circulating Lymphocytes in Patients with Sepsis

    Directory of Open Access Journals (Sweden)

    Raul de Pablo

    2014-01-01

    Full Text Available Sepsis is a systemic inflammatory response syndrome due to infection. The incidence rate is estimated to be up to 19 million cases worldwide per year and the number of cases is rising. Infection triggers a complex and prolonged host response, in which both the innate and adaptive immune response are involved. The disturbance of immune system cells plays a key role in the induction of abnormal levels of immunoregulatory molecules. Furthermore, the involvement of effector immune system cells also impairs the host response to the infective agents and tissue damage. Recently, postmortem studies of patients who died of sepsis have provided important insights into why septic patients die and showed an extensive depletion of CD4 and CD8 lymphocytes and they found that circulating blood cells showed similar findings. Thus, the knowledge of the characterization of circulating lymphocyte abnormalities is relevant for the understanding of the sepsis pathophysiology. In addition, monitoring the immune response in sepsis, including circulating lymphocyte subsets count, appears to be potential biomarker for predicting the clinical outcome of the patient. This paper analyzes the lymphocyte involvement and dysfunction found in patients with sepsis and new opportunities to prevent sepsis and guide therapeutic intervention have been revealed.

  20. 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.

  1. Analogues of atmospheric circulation to probe extreme and rare events

    Science.gov (United States)

    Yiou, P.

    2015-12-01

    Analogues of atmospheric circulation have had many applications, from weather prediction to the downscaling of climate variables. The main assumptions behind this methodology are that climate variables (such as temperature or precipitation) are linked a large-scale atmospheric predictand, which is usually taken as sea-level pressure, and that such predictands recur through time. They offer a possibility to estimate probability distributions of a climate variable, conditional to patterns of atmospheric circulation. In addition, this methodology allows the quantification of unusual weather patterns that have been observed. I will represent a way to use analogues of circulation for the detection/attribution of extreme events of precipitation and temperature. This approach will be illustrated on test cases, including the warm European winter of 2006/2007, the extremes of precipitation over Southern UK and northwestern France in January 2014, and the European summer of 2015. I will show how this analysis provides a low-cost estimate of the fraction of attributable risk (FAR) for extreme events that verify the above mentioned hypotheses. Such an analysis can be performed in continuous time with reanalysis data and meteorological observations.

  2. Novel reassortant swine influenza viruses are circulating in Danish pigs

    DEFF Research Database (Denmark)

    Breum, Solvej Østergaard; Hjulsager, Charlotte Kristiane; Trebbien, Ramona;

    of the reassortant viruses comprised a HA gene similar to H1 of H1N1 avian-like swine influenza virus (SIV) and a NA gene most closely related to N2 gene of human H3N2 influenza virus that circulated in humans in the mid 1990s. The internal genes of this reassortant virus with the subtype H1avN2hu all belonged......The Danish surveillance program for influenza A virus in pigs has revealed that two novel reassortant swine influenza viruses may now be circulating in the Danish swine population, since they each have been detected in at least two submissions from different herds in 2011 as well as in 2012. One...... to the H1N1 avian-like SIV lineages. Until now this novel virus H1avN2hu has only been detected in Danish swine. The other novel reassortant virus contained the HA gene from H1N1pdm09 virus and a NA gene similar to the N2 gene of H3N2 SIV that have been circulating in European swine since the mid 1980s...

  3. Summertime winds and direct cyclonic circulation: observations from Lake Geneva

    Directory of Open Access Journals (Sweden)

    U. Lemmin

    Full Text Available Records of wind, air temperature and air pressure from nine stations, situated along the shoreline of Lake Geneva, Switzerland, were analyzed for the summer period May to September. At all stations the consistent appearance of significant spectral peaks and changes in wind direction at the diurnal frequency indicates the importance of lake-land breezes. It is shown that the surrounding topography has a strong modifying effect (temporal and spatial on the lake-land breeze. Superimposed on this cyclic wind pattern, short episodes of strong winds with long fetch over parts of Lake Geneva are regularly observed. Both of these winds exert a spatially variable wind stress over the lake surface on the same time scale. Typical examples of the expected lake's response are presented, among them the seasonally persistent gyre in the central part of the lake. Evidence is provided that this dominant circulation is part of a direct cyclonic circulation, generated by the curl of the diurnal wind field. It is concluded that the mean circulation is caused by these winds and affected by the topography of the surrounding land.

  4. Transcriptome kinetics of circulating neutrophils during human experimental endotoxemia.

    Directory of Open Access Journals (Sweden)

    Stan de Kleijn

    Full Text Available Polymorphonuclear cells (neutrophils play an important role in the systemic inflammatory response syndrome and the development of sepsis. These cells are essential for the defense against microorganisms, but may also cause tissue damage. Therefore, neutrophil numbers and activity are considered to be tightly regulated. Previous studies have investigated gene transcription during experimental endotoxemia in whole blood and peripheral blood mononuclear cells. However, the gene transcription response of the circulating pool of neutrophils to systemic inflammatory stimulation in vivo is currently unclear. We examined neutrophil gene transcription kinetics in healthy human subjects (n = 4 administered a single dose of endotoxin (LPS, 2 ng/kg iv. In addition, freshly isolated neutrophils were stimulated ex vivo with LPS, TNFα, G-CSF and GM-CSF to identify stimulus-specific gene transcription responses. Whole transcriptome microarray analysis of circulating neutrophils at 2, 4 and 6 hours after LPS infusion revealed activation of inflammatory networks which are involved in signaling of TNFα and IL-1α and IL-1β. The transcriptome profile of inflammatory activated neutrophils in vivo reflects extended survival and regulation of inflammatory responses. These changes in neutrophil transcriptome suggest a combination of early activation of circulating neutrophils by TNFα and G-CSF and a mobilization of young neutrophils from the bone marrow.

  5. 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.

  6. Stability analysis on natural circulation boiling water reactors

    Energy Technology Data Exchange (ETDEWEB)

    Metz, Peter

    1999-05-01

    The purpose of the study is a stability analysis of the simplified boiling water reactor concept. A fluid dynamics code, DYNOS, was developed and successfully validated against FRIGG and DESIRE data and a stability benchmark on the Ringhals 1 forced circulation BWR. Three simplified desings were considered in the analysis: The SWRIOOO by Siemens and the SBWR and ESBWR from the General Electric Co. For all three design operational characteristics, i.e. power versus flow rate maps, were calculated. The effects which different geometric and operational parameters, such as the riser height, inlet subcooling etc., have on the characteristics have been investigated. Dynamic simulations on the three simplified design revealed the geysering and the natural circulation oscillations modes only. They were, however, only encountered at pressure below 0.6 MPa. Stability maps for all tree simplified BWRs were calculated and plotted. The study concluded that a fast pressurisation of the reactor vessel is necessary to eliminate the possibility of geysering or natural circulation oscillations mode instability. (au) 26 tabs., 88 ills.

  7. Three-dimensional decomposition method of global atmospheric circulation

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    By adopting the idea of three-dimensional Walker, Hadley and Rossby stream functions, the global atmospheric circulation can be considered as the sum of three stream functions from a global per- spective. Therefore, a mathematical model of three-dimensional decomposition of global atmospheric circulation is proposed and the existence and uniqueness of the model are proved. Besides, the model includes a numerical method leading to no truncation error in the discrete three-dimensional grid points. Results also show that the three-dimensional stream functions exist and are unique for a given velocity field. The mathematical model shows the generalized form of three-dimensional stream func- tions equal to the velocity field in representing the features of atmospheric motion. Besides, the vertical velocity calculated through the model can represent the main characteristics of the vertical motion. In sum, the three-dimensional decomposition of atmospheric circulation is convenient for the further in- vestigation of the features of global atmospheric motions.

  8. 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.

  9. Tropospheric circulation during the early twentieth century Arctic warming

    Science.gov (United States)

    Wegmann, Martin; Brönnimann, Stefan; Compo, Gilbert P.

    2016-06-01

    The early twentieth century Arctic warming (ETCAW) between 1920 and 1940 is an exceptional feature of climate variability in the last century. Its warming rate was only recently matched by recent warming in the region. Unlike recent warming largely attributable to anthropogenic radiative forcing, atmospheric warming during the ETCAW was strongest in the mid-troposphere and is believed to be triggered by an exceptional case of natural climate variability. Nevertheless, ultimate mechanisms and causes for the ETCAW are still under discussion. Here we use state of the art multi-member global circulation models, reanalysis and reconstruction datasets to investigate the internal atmospheric dynamics of the ETCAW. We investigate the role of boreal winter mid-tropospheric heat transport and circulation in providing the energy for the large scale warming. Analyzing sensible heat flux components and regional differences, climate models are not able to reproduce the heat flux evolution found in reanalysis and reconstruction datasets. These datasets show an increase of stationary eddy heat flux and a decrease of transient eddy heat flux during the ETCAW. Moreover, tropospheric circulation analysis reveals the important role of both the Atlantic and the Pacific sectors in the convergence of southerly air masses into the Arctic during the warming event. Subsequently, it is suggested that the internal dynamics of the atmosphere played a major role in the formation in the ETCAW.

  10. The Biology of Circulating MicroRNAs in Cardiovascular Disease

    Science.gov (United States)

    Min, Pil-Ki; Chan, Stephen Y.

    2015-01-01

    Since their first description in mammalian cells, more than 2,500 microRNA molecules have been predicted or verified within human cells. Recently, extracellular microRNAs have been described, protected from degradation by specialized packaging in extracellular vesicles or RNA-binding proteins. Such microRNAs, circulating in the bloodstream and extracellular space, have been proposed as attractive candidates as both diagnostic and prognostic biomarkers in various diseases, including a spectrum of cardiovascular conditions. Moreover, consistent with our evolving appreciation of the role of exosomes and microvesicles in intercellular communication, it has been proposed that delivery of active microRNAs to recipient tissues may serve as a primary mode of intercellular communication. Indeed, the transfer of functional microRNAs has been demonstrated in in vitro models and has been reported in a few in vivo contexts. In this review, we will discuss the recent data of circulating microRNAs in cardiovascular disease with an emphasis on their potential roles as diagnostic and prognostic biomarkers as well as the challenges of proving their potential clinical utility. In addition, we will discuss the evidence regarding the role of circulating microRNAs in intercellular communication as well as known molecular factors affecting their packaging, transfer, and uptake in recipient cardiovascular cell types. PMID:26046787

  11. Circulating Nucleosomes and Nucleosome Modifications as Biomarkers in Cancer

    Science.gov (United States)

    McAnena, Peter; Brown, James A. L.; Kerin, Michael J.

    2017-01-01

    Traditionally the stratification of many cancers involves combining tumour and clinicopathological features (e.g., patient age; tumour size, grade, receptor status and location) to inform treatment options and predict recurrence risk and survival. However, current biomarkers often require invasive excision of the tumour for profiling, do not allow monitoring of the response to treatment and stratify patients into broad heterogeneous groups leading to inconsistent treatment responses. Here we explore and describe the benefits of using circulating biomarkers (nucleosomes and/or modifications to nucleosomes) as a non-invasive method for detecting cancer and monitoring response to treatment. Nucleosomes (DNA wound around eight core histone proteins) are responsible for compacting our genome and their composition and post-translational modifications are responsible for regulating gene expression. Here, we focus on breast and colorectal cancer as examples where utilizing circulating nucleosomes as biomarkers hold real potential as liquid biopsies. Utilizing circulating nucleosomes as biomarkers is an exciting new area of research that promises to allow both the early detection of cancer and monitoring of treatment response. Nucleosome-based biomarkers combine with current biomarkers, increasing both specificity and sensitivity of current tests and have the potential to provide individualised precision-medicine based treatments for patients. PMID:28075351

  12. Sensitivity of the Meridional Overturning Circulation to the Pattern of the Surface Density Flux

    Science.gov (United States)

    2010-09-01

    a better prognosis of anthropogenic climate change . Figure 1. Classical representation of the global thermohaline circulation and oceanic...modeling efforts and long-term strategy related to climate change . 15. NUMBER OF PAGES 105 14. SUBJECT TERMS Meridional Overturning Circulation ... Thermohaline Circulation , Thermocline, Residual-Mean Theory, Air-Sea Fluxes, Surface Density Flux , Mixed-Layer Density, Water-mass Transformation

  13. Impact of Stratospheric Ozone Distribution on Features of Tropospheric Circulation

    Science.gov (United States)

    Barodka, Siarhei; Krasouski, Aliaksandr; Mitskevich, Yaroslav; Shalamyansky, Arkady

    2016-04-01

    In this work we study connections between stratospheric ozone distribution and general circulation patterns in the troposphere and aim to investigate the causal relationship between them, including the practical side of the influence of stratospheric ozone on tropospheric medium-range weather and regional climate. Analysis of several decades of observational data, which has been performed at the A.I. Voeikov Main Geophysical Observatory, suggests a clear relation between the stratospheric ozone distribution, upper stratospheric temperature field and planetary-scale air-masses boundaries in the troposphere [1]. Furthermore, it has been shown that each global air-mass, which can be attributed to the corresponding circulation cell in a conceptual model of tropospheric general circulation, has a distinct "regime" of ozone vertical distribution in the stratosphere [1-3]. Proceeding from atmospheric reanalyses combined with satellite and ground-based observations, we study time evolution of the upper-level frontal zones (stationary fronts) with the relevant jet streams, which can be treated as boundaries of global air-masses, in connection with the tropopause height and distribution of ozone in the stratosphere. For that, we develop an algorithm for automated identification of jet streams, stationary fronts and tropopause surface from gridded data (reanalyses or modelling results), and apply it for several cases associated with rapid changes in the stratospheric temperature and ozone fields, including SSW events over Eastern Siberia. Aiming to study the causal relationship between the features of tropospheric circulation and changes in the stratospheric ozone field, we estimate the time lag between these categories of processes on different time scales. Finally, we discuss the possibility to use the elementary circulation mechanisms classification (by B.L. Dzerdzeevski) in connection with analysis of the stratospheric ozone field and the relevant stratosphere

  14. Reconstructing Ocean Circulation using Coral (triangle)14C Time Series

    Energy Technology Data Exchange (ETDEWEB)

    Kashgarian, M; Guilderson, T P

    2001-02-23

    We utilize monthly {sup 14}C data derived from coral archives in conjunction with ocean circulation models to address two questions: (1) how does the shallow circulation of the tropical Pacific vary on seasonal to decadal time scales and (2) which dynamic processes determine the mean vertical structure of the equatorial Pacific thermocline. Our results directly impact the understanding of global climate events such as the El Nino-Southern Oscillation (ENSO). To study changes in ocean circulation and water mass distribution involved in the genesis and evolution of ENSO and decadal climate variability, it is necessary to have records of climate variables several decades in length. Continuous instrumental records are limited because technology for continuous monitoring of ocean currents (e.g. satellites and moored arrays) has only recently been available, and ships of opportunity archives such as COADS contain large spatial and temporal biases. In addition, temperature and salinity in surface waters are not conservative and thus can not be independently relied upon to trace water masses, reducing the utility of historical observations. Radiocarbon in sea water is a quasi-conservative water mass tracer and is incorporated into coral skeletal material, thus coral {sup 14}C records can be used to reconstruct changes in shallow circulation that would be difficult to characterize using instrumental data. High resolution {Delta}{sup 14}C timeseries such as ours, provide a powerful constraint on the rate of surface ocean mixing and hold great promise to augment one time oceanographic surveys. {Delta}{sup 14}C timeseries such as these, not only provide fundamental information about the shallow circulation of the Pacific, but can also be directly used as a benchmark for the next generation of high resolution ocean models used in prognosticating climate. The measurement of {Delta}{sup 14}C in biological archives such as tree rings and coral growth bands is a direct record of

  15. The influence of glacial ice sheets on Atlantic meridional overturning circulation through atmospheric circulation change under glacial climate

    Science.gov (United States)

    Sherriff-Tadano, Sam; Abe-Ouchi, Ayako; Yoshimori, Masakazu; Oka, Akira; Chan, Wing-Le

    2016-04-01

    Recent coupled modeling studies have shown that the existence of the glacial ice sheets intensifies the Atlantic meridional overturning circulation (AMOC). Since this may play an important role in maintaining a strong AMOC over the last glacial period, which is suggested by recent reconstruction study, it is very important to understand the process by which glacial ice sheets intensify the AMOC. Here, a decoupled simulation is conducted to investigate the effect of wind change due to glacial ice sheets on the AMOC, the crucial region where wind modifies the AMOC and the mechanism, which remained elusive in previous studies. First, from atmospheric general circulation model (AGCM) experiments, the effect of glacial ice sheets on the surface wind is evaluated. Second, from ocean general circulation model (OGCM) experiments, the influence of the wind stress change on the AMOC is evaluated by applying only the changes in the surface wind as a boundary condition, while leaving surface heat and freshwater fluxes unchanged. Moreover, several sensitivity experiments are conducted. Using the AGCM, glacial ice sheets are applied individually. Using the OGCM, changes in the wind are applied regionally or at different magnitudes, ranging from the full glacial to modern levels. These experiments demonstrate that glacial ice sheets intensify the AMOC through an increase in the wind stress curl mainly at the North Atlantic mid-latitudes. This intensification is caused by the increased Ekman upwelling and gyre transport of salt while the change in sea ice transport works as a negative, though minor, feedback.

  16. 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.

  17. 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.

  18. 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.

  19. Disputes over Circulation of Rural Land Contractual Management Right and Control Countermeasures

    Institute of Scientific and Technical Information of China (English)

    Deyu; DU

    2013-01-01

    On the basis of current situations of disputes over rural land contractual management right,this paper analyzes causes of disputes from four aspects. It states that controlling disputes,regulating and strengthening land circulation in accordance with laws are core works of new socialist countryside construction and rural reform. Finally,it presents five control countermeasures,including improving laws and regulations on circulation of rural land contractual management right,strengthening popularization and guidance of relevant laws and regulations,government departments administering in accordance with laws,stressing management of land contractual management right circulation contract,and establishing and perfecting land circulation intermediaries to realize market-oriented circulation.

  20. Government-oriented Land Circulation from the Perspective of Social Governance

    Institute of Scientific and Technical Information of China (English)

    2012-01-01

    This paper firstly summed up institutional change of land circulation after the foundation of new China,analyzed main characteristics and internal drawbacks of government-oriented land circulation,discussed the governance cost of local government-oriented land circulation,and evaluated the governance performance on the basis of the transaction cost theory. Results show that local government-oriented land circulation is a resource allocation mode for maximizing benefits of an organization,and its microscopic functions and values are mainly encouragement and restriction,while its macroscopic functions are comprehensive administration of results of state policies. Finally,it put forward policy suggestions for improving local government-oriented land circulation: cultivating diversified rural land circulation modes and regulating acts of local officials; stressing that building harmonious land circulation mechanism is the responsibility of central government; setting up recognition mechanism of the public to local government.

  1. Red Sea circulation during marine isotope stage 5e

    Science.gov (United States)

    Siccha, Michael; Biton, Eli; Gildor, Hezi

    2015-04-01

    We have employed a regional Massachusetts Institute of Technology oceanic general circulation model of the Red Sea to investigate its circulation during marine isotope stage (MIS) 5e, the peak of the last interglacial, approximately 125 ka before present. Compared to present-day conditions, MIS 5e was characterized by higher Northern Hemisphere summer insolation, accompanied by increases in air temperature of more than 2°C and global sea level approximately 8 m higher than today. As a consequence of the increased seasonality, intensified monsoonal conditions with increased winds, rainfall, and humidity in the Red Sea region are evident in speleothem records and supported by model simulations. To assess the dominant factors responsible for the observed changes, we conducted several sensitivity experiments in which the MIS 5 boundary conditions or forcing parameters were used individually. Overall, our model simulation for the last interglacial maximum reconstructs a Red Sea that is colder, less ventilated and probably more oligotrophic than at present day. The largest alteration in Red Sea circulation and properties was found for the simulation of the northward displacement and intensification of the African tropical rain belt during MIS 5e, leading to a notable increase in the fresh water flux into the Red Sea. Such an increase significantly reduced the Red Sea salinity and exchange volume of the Red Sea with the Gulf of Aden. The Red Sea reacted to the MIS 5e insolation forcing by the expected increase in seasonal sea surface temperature amplitude and overall cooling caused by lower temperatures during deep water formation in winter.

  2. Hyperbilirubinemia after extracorporeal circulation surgery: A recent and prospective study

    Institute of Scientific and Technical Information of China (English)

    Yong An; Ying-Bin Xiao; Qian-Jin Zhong

    2006-01-01

    AIM: To clarify the incidence and nature of postoperative hyperbilirubinemia in patients after modern extracorporeal circulation, to analyze possible perioperative risk factors, and to elucidate the clinical significance of postoperative hyperbilirubinemia associated morality and morbidity.METHODS: Between March 2005 and May 2006, three hundred and eighty six consecutive patients undergoing extracorporeal circulation surgery due to a variety of cardiac lesions were investigated prospectively. The incidence of postoperative hyperbilirubinemia was defined as a serum total bilirubin concentration of more than 51 μmol/L. Several perioperative parameters were compared by logistic regression between hyperbilirubinemia and non-hyperbilirubinemia patients to determine possible risk factors contributing to postoperative hyperbilirubinemia and mortality.RESULTS: Overall incidence of postoperative hyperbilirubinemia was 25.3% (98/386). In patients with postoperative hyperbilirubinemia, 56.2%reached peak total bilirubin concentration on the first postoperative day, 33.5% on the second day, and 10.3%on the seventh day. Eighty percent of the increase of total bilirubin resulted from an increase of both conjugated and unconjugated bilirubin. Development of postoperative hyperbilirubinemia was associated with a higher mortality (P < 0.01), longer duration of mechanical ventilation (P < 0.05) and longer ICU stay time (P < 0.05). Preoperative total bilirubin concentration, preoperative right atrium pressure,numbers of valves replaced and of blood transfusion requirement were identified as important predictors for postoperative hyperbilirubinemia.CONCLUSION: Early postoperative hyperbilirubinemia after modern extracorporeal circulation is mainly caused by an increase in both conjugated and unconjugated bilirubin, and is associated with a high mortality.Important contributing factors are the preoperative total bilirubin concentration, preoperative severity of right atrial

  3. Automated scoping methodology for liquid metal natural circulation small reactor

    Energy Technology Data Exchange (ETDEWEB)

    Son, Hyung M.; Suh, Kune Y., E-mail: kysuh@snu.ac.kr

    2014-07-01

    Highlights: • Automated scoping methodology for natural circulation small modular reactor is developed. • In-house code is developed to carry out system analysis and core geometry generation during scoping. • Adjustment relations are obtained to correct the critical core geometry out of diffusion theory. • Optimized design specification is found using objective function value. • Convex hull volume is utilized to quantify the impact of different constraints on the scope range. - Abstract: A novel scoping method is proposed that can automatically generate design variable range of the natural circulation driven liquid metal cooled small reactor. From performance requirements based upon Generation IV system roadmap, appropriate structure materials are selected and engineering constraints are compiled based upon literature. Utilizing ASME codes and standards, appropriate geometric sizing criteria on constituting components are developed to ensure integrity of the system during its lifetime. In-house one dimensional thermo-hydraulic system analysis code is developed based upon momentum integral model and finite element methods to deal with non-uniform descritization of temperature nodes for convection and thermal diffusion equation of liquid metal coolant. In order to quickly generate critical core dimensions out of given unit cell information, an adjustment relation that relates the critical geometry estimated from one-group diffusion and that from MCNP code is constructed and utilized throughout the process. For the selected unit cell dimension ranges, burnup calculations are carried out to check the cores can generate energy over the reactor lifetime. Utilizing random method, sizing criteria, and in-house analysis codes, an automated scoping methodology is developed. The methodology is applied to nitride fueled integral type lead cooled natural circulation reactor concept to generate design scopes which satisfies given constraints. Three dimensional convex

  4. DOPPLER SIGNATURES OF THE ATMOSPHERIC CIRCULATION ON HOT JUPITERS

    Energy Technology Data Exchange (ETDEWEB)

    Showman, Adam P.; Lewis, Nikole K. [Department of Planetary Sciences and Lunar and Planetary Laboratory, The University of Arizona, 1629 University Boulevard, Tucson, AZ 85721 (United States); Fortney, Jonathan J. [Department of Astronomy and Astrophysics, University of California, Santa Cruz, CA 95064 (United States); Shabram, Megan, E-mail: showman@lpl.arizona.edu [Department of Astronomy, University of Florida, 211 Bryant Space Science Center, Gainesville, FL 32611-2055 (United States)

    2013-01-01

    The meteorology of hot Jupiters has been characterized primarily with thermal measurements, but recent observations suggest the possibility of directly detecting the winds by observing the Doppler shift of spectral lines seen during transit. Motivated by these observations, we show how Doppler measurements can place powerful constraints on the meteorology. We show that the atmospheric circulation-and Doppler signature-of hot Jupiters splits into two regimes. Under weak stellar insolation, the day-night thermal forcing generates fast zonal jet streams from the interaction of atmospheric waves with the mean flow. In this regime, air along the terminator (as seen during transit) flows toward Earth in some regions and away from Earth in others, leading to a Doppler signature exhibiting superposed blueshifted and redshifted components. Under intense stellar insolation, however, the strong thermal forcing damps these planetary-scale waves, inhibiting their ability to generate jets. Strong frictional drag likewise damps these waves and inhibits jet formation. As a result, this second regime exhibits a circulation dominated by high-altitude, day-to-night airflow, leading to a predominantly blueshifted Doppler signature during transit. We present state-of-the-art circulation models including non-gray radiative transfer to quantify this regime shift and the resulting Doppler signatures; these models suggest that cool planets like GJ 436b lie in the first regime, HD 189733b is transitional, while planets hotter than HD 209458b lie in the second regime. Moreover, we show how the amplitude of the Doppler shifts constrains the strength of frictional drag in the upper atmospheres of hot Jupiters. If due to winds, the {approx}2 km s{sup -1} blueshift inferred on HD 209458b may require drag time constants as short as 10{sup 4}-10{sup 6} s, possibly the result of Lorentz-force braking on this planet's hot dayside.

  5. The South Asian Monsoon Circulation in Moist Isentropic coordinates

    Science.gov (United States)

    Thazhe Purayil, Sabin; Pauluis, Olivier

    2016-04-01

    The atmospheric circulation and thermodynamic structure during the South Asian Summer Monsoon season is analyzed in isentropic coordinates through the mass transport represented in terms of the potential temperature and equivalent potential temperature. This approach, originally developed to analyze the global meridional circulation, makes it possible to identify the thermodynamic properties of the inflow and outflow of different air mass. To understand the thermodynamic properties of air mass in south Asian monsoon region, we have used three diagnostics; a) the joint distribution of the mass transport as a function of dry and moist entropy, b) the vertical mass flux over the monsoon domain and c) the mass transport and isentropic thickness for different moist ventilation range of tropical atmosphere. The thermodynamic properties of the various air masses, such as the inflow of warm moist air in the boundary layer, upper tropospheric outflow, and midlatitude dry air intrusion are being systematically identified. The isentropic distribution of the vertical mass flux transport in terms of equivalent potential temperature is used to explain the characteristics of ascending and descending air parcels over the Indian subcontinent. Diagnosis based on the isentropic thickness reveals that the regional monsoon circulation and associated precipitation features can be systematically explained by this method. This technique is used to study the evolution of the monsoon flow in the seasonal scale. We used the data from AMIP-type simulations carried out with prescribed Sea Surface Temperature and sea ice for a 25 year period (1981-2005) from the GFDL High-resolution atmospheric model (HiRAM) with an average grid spacing of ~25km over the globe.

  6. Circulating irisin is lower in gestational diabetes mellitus.

    Science.gov (United States)

    Zhao, Liang; Li, Jun; Li, Zhao-Liang; Yang, Jie; Li, Ming-Long; Wang, Gong-Ling

    2015-01-01

    Irisin is a newly identified myokine. Several studies have reported irisin concentrations in patients with gestational diabetes mellitus (GDM), but because of smaller sample sizes, the data from previous reports showed a wide range in serum/plasma irisin. Therefore, the present investigation is designed to summarize a precise confidence interval of circulating irisin in participants with GDM from a cross-sectional study in Chinese population and a meta-analysis for validation. Serum irisin was tested in patients with GDM and healthy controls (newly diagnosed cases: 61 and matched controls: 61) in the cross-sectional study. The two groups of participants were matched for age and pregnancy duration. Furthermore, we did a comprehensive meta-analysis to confirm whether serum/plasma irisin differs between participants with GDM and controls. Articles reported "circulating irisin and GDM" in Medline, PubMed, and EMBase were obtained, with the key word "myokine" or "irisin". The comparison was analyzed by Review Manager 5.2. In the cross-sectional investigation, serum irisin showed a significant lower level in the GDM patients, compared with that in the control group. In the meta-analysis study, the summarized results of the present 5 studies in which 632 participants were included indicated that there was a lower level irisin of -58.68 ng/mL [95% confidence interval (CI)](-113.42, -3.93, P=0.04) in GDM patients than in the control group. The present cross-sectional investigation and meta-analysis is the first to show significant lower circulating irisin in subjects with GDM.

  7. Measurement of cardiac output from dynamic pulmonary circulation time CT

    Energy Technology Data Exchange (ETDEWEB)

    Yee, Seonghwan, E-mail: Seonghwan.Yee@Beaumont.edu [Department of Radiation Oncology, Beaumont Health System, Royal Oak, Michigan 48073 (United States); Scalzetti, Ernest M. [Department of Radiology, SUNY Upstate Medical University, Syracuse, New York 13210 (United States)

    2014-06-15

    Purpose: To introduce a method of estimating cardiac output from the dynamic pulmonary circulation time CT that is primarily used to determine the optimal time window of CT pulmonary angiography (CTPA). Methods: Dynamic pulmonary circulation time CT series, acquired for eight patients, were retrospectively analyzed. The dynamic CT series was acquired, prior to the main CTPA, in cine mode (1 frame/s) for a single slice at the level of the main pulmonary artery covering the cross sections of ascending aorta (AA) and descending aorta (DA) during the infusion of iodinated contrast. The time series of contrast changes obtained for DA, which is the downstream of AA, was assumed to be related to the time series for AA by the convolution with a delay function. The delay time constant in the delay function, representing the average time interval between the cross sections of AA and DA, was determined by least square error fitting between the convoluted AA time series and the DA time series. The cardiac output was then calculated by dividing the volume of the aortic arch between the cross sections of AA and DA (estimated from the single slice CT image) by the average time interval, and multiplying the result by a correction factor. Results: The mean cardiac output value for the six patients was 5.11 (l/min) (with a standard deviation of 1.57 l/min), which is in good agreement with the literature value; the data for the other two patients were too noisy for processing. Conclusions: The dynamic single-slice pulmonary circulation time CT series also can be used to estimate cardiac output.

  8. The Dichromatic Number of Infinite Families of Circulant Tournaments

    Directory of Open Access Journals (Sweden)

    Javier Nahid

    2017-02-01

    Full Text Available The dichromatic number dc(D of a digraph D is defined to be the minimum number of colors such that the vertices of D can be colored in such a way that every chromatic class induces an acyclic subdigraph in D. The cyclic circulant tournament is denoted by T=C→2n+1(1,2,…,n$T = \\overrightarrow C _{2n + 1} (1,2, \\ldots ,n$, where V (T = ℤ2n+1 and for every jump j ∈ {1, 2, . . . , n} there exist the arcs (a, a + j for every a ∈ ℤ2n+1. Consider the circulant tournament C→2n+1〈k〉$\\overrightarrow C _{2n + 1} \\left\\langle k \\right\\rangle $ obtained from the cyclic tournament by reversing one of its jumps, that is, C→2n+1 〈k〉$\\overrightarrow C _{2n + 1} \\left\\langle k \\right\\rangle $ has the same arc set as C→2n+1(1,2,…,n$\\overrightarrow C _{2n + 1} (1,2, \\ldots ,n$ except for j = k in which case, the arcs are (a, a − k for every a ∈ ℤ2n+1. In this paper, we prove that dc(C→2n+1 〈k〉∈{2,3,4}$dc ( {\\overrightarrow C _{2n + 1} \\left\\langle k \\right\\rangle } \\in \\{ 2,3,4\\}$ for every k ∈ {1, 2, . . . , n}. Moreover, we classify which circulant tournaments C→2n+1 〈k〉$\\overrightarrow C _{2n + 1} \\left\\langle k \\right\\rangle$ are vertex-critical r-dichromatic for every k ∈ {1, 2, . . . , n} and r ∈ {2, 3, 4}. Some previous results by Neumann-Lara are generalized.

  9. Circulating CD14+ monocytes in patients with aortic stenosis

    Institute of Scientific and Technical Information of China (English)

    Sara Shimoni; Valery Meledin; Iris Bar; Jacob Fabricant; Gera Gandelman; Jacob George

    2016-01-01

    BackgroundCalcific aortic stenosis (AS) is an active process sharing similarities with atherosclerosis and chronic inflammation. The pathophysiology of AS is notable for three cardinal components: inflammation, fibrosis and calcification. Monocytes play a role in each of these processes. The role of circulating monocytes in AS is not clear. The aim of the present study was to study an association between cir-culating apoptotic and non apoptotic CD14+ monocytes and AS features.MethodsWe assessed the number of CD14+ monocytes and apoptotic monocytes in 54 patients with significant AS (aortic valve area 0.74 ± 0.27 cm2) and compared them to 33 patients with similar risk factors and no valvular disease. The level of CD14+ monocytes and apoptotic monocytes was assessed by flow cytometry.ResultsThere was no difference in the risk factor profile and known coronary or peripheral vascular diseases between patients with AS and controls.Pa-tients with AS exhibited increased numbers of CD14+ monocytes as compared to controls (9.9% ± 4.9%vs. 7.7% ± 3.9%,P= 0.03). CD14+ monocyte number was related to age and the presence and severity of AS. In patients with AS, both CD14+ monocytes and apoptotic mono-cytes were inversely related to aortic valve area.ConclusionsPatients with significant AS have increased number of circulating CD14+ monocytes and there is an inverse correlation between monocyte count and aortic valve area. These findings may suggest that inflammation is operative not only in early valve injury phase, but also at later developed stages such as calcification when AS is severe.

  10. Linear system identification of a cold flow circulating fluidized bed

    Energy Technology Data Exchange (ETDEWEB)

    Panday, R [West Virginia Univ., Morgantown, WV (United States); Woerner, B D [West Virginia Univ., Morgantown, WV (United States); Ludlow, J C [National Energy Technology Lab. (NETL), Morgantown, WV (United States); Shadle, L J [National Energy Technology Lab. (NETL), Morgantown, WV (United States); Boyle, E J [National Energy Technology Lab. (NETL), Morgantown, WV (United States)

    2009-02-01

    Knowledge of the solids circulation rate (SCR) is essential to the control and improved performance of a circulating fluidized bed system. In the present work, the noise model is derived using the prediction error method considering process and measurement noises acting on the cold flow circulating fluidized bed (CFCFB) with a cork particulate material. The outputs of the initial model are the total pressure drop across the riser, the pressure drop across the crossover, the pressure drop across the primary cyclone, the total pressure drop across the stand-pipe, the pressure drop across the loop seal, and the SCR. The stochastic estimate of SCR is determined from the noise model using the stochastic pressure drop estimates. The deterministic estimate is obtained through the inputs taken as move air flow, riser aeration, and loop seal fluidization air that are all independent variables of the given setup and under the control of the user. The theory has been developed to convert a complete blackbox model to a grey box model through the output-to-state transformation such that both the models of the CFCFB consists of all these output variables as the states of the system, and only pressure drops across the system as the output measurements. Thus, the final models do not include any fictitious terms and they are defined only in terms of physical parameters of the given system. Both components of SCR are separately analysed. The combined SCR response of both the noise model and deterministic model is compared with the validation data set of this state variable in terms of modelfit, and the results are shown.

  11. Circulating and Vascular Bioactive Factors during Hypertension in Pregnancy.

    Science.gov (United States)

    Tanbe, Alain F; Khalil, Raouf A

    2010-03-01

    Normal pregnancy is associated with significant vascular remodeling in the uterine and systemic circulation in order to meet the metabolic demands of the mother and developing fetus. The pregnancy-associated vascular changes are largely due to alterations in the amount/activity of vascular mediators released from the endothelium, vascular smooth muscle and extracellular matrix. The endothelium releases vasodilator substances such as nitric oxide, prostacyclin and hyperpolarizing factor as well as vasoconstrictor factors such as endothelin, angiotensin II and thromboxane A(2). Vascular smooth muscle contraction is mediated by intracellular free Ca(2+) concentration ([Ca(2+)](i)), and [Ca(2+)](i) sensitization pathways such as protein kinase C, Rho-kinase and mitogen-activated protein kinase. Extracellular matrix and vascular remodeling are regulated by matrix metalloproteases. Hypertension in pregnancy and preeclampsia are major complications and life threatening conditions to both the mother and fetus, precipitated by various genetic, dietary and environmental factors. The initiating mechanism of preeclampsia and hypertension in pregnancy is unclear; however, most studies have implicated inadequate invasion of cytotrophoblasts into the uterine artery, leading to reduction in the uteroplacental perfusion pressure and placental ischemia/hypoxia. This placental hypoxic state is thought to induce the release of several circulating bioactive factors such as growth factor inhibitors, anti-angiogenic proteins, inflammatory cytokines, reactive oxygen species, hypoxia-inducible factors, and vascular receptor antibodies. Increases in the plasma levels and vascular content of these factors during pregnancy could cause an imbalance in the vascular mediators released from the endothelium, smooth muscle and extracellular matrix, and lead to severe vasoconstriction and hypertension. This review will discuss the interactions between the various circulating bioactive factors and

  12. Experimental and Analytical Modeling of Natural Circulation and Forced Circulation BWRs : Thermal-Hydraulic, Core-Wide, and Regional Stability Phenomena

    NARCIS (Netherlands)

    Furuya, M.

    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, al

  13. Thermohaline circulations and global climate change. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Hanson, H.P.

    1996-10-01

    This report discusses results from the project entitled Thermohaline Circulations and Global Climate Change. Results are discussed in three sections related to the development of the Miami Isopycnic Coordinate Ocean Model (MICOM), surface forcing of the ocean by the atmosphere, and experiments with the MICOM related to the problem of the ocean`s response to global climate change. It will require the use of a global, coupled ocean-atmospheric climate model to quantify the feedbacks between ocean and atmosphere associated with climate changes. The results presented here do provide guidance for such studies in the future.

  14. Singularity of Sparse Circulant Matrices is NP-complete

    CERN Document Server

    Toli, Ilia

    2009-01-01

    It is shown by Karp reduction that deciding the singularity of $(2^n - 1) \\times (2^n - 1)$ sparse circulant matrices (SC problem) is NP-complete. We can write them only implicitly, by indicating values of the $2 + n(n + 1)/2$ eventually nonzero entries of the first row and can make all matrix operations with them. The positions are $0, 1, 2^{i} + 2^{j}$. The complexity parameter is $n$. Mulmuley's work on the rank of matrices \\cite{Mulmuley87} makes SC stand alone in a list of 3,000 and growing NP-complete problems.

  15. Changes in tropical circulation in a warming climate

    Science.gov (United States)

    Chou, C.

    2013-12-01

    Precipitation is experiencing a great change under global warming. Two major processes induced changes in precipitation are thermodynamic and dynamic contributions. The former is related to changes in water vapor and the latter is associated with changes in vertical velocity. Since water vapor increases almost everywhere, the thermodynamic contribution is determined by the corresponding mean vertical motion: positive for ascents and negative for descents, which creates a 'wet-get-wetter and dry-get-drier' tendency. The dynamic contribution, on the other hand, is much more complicated, especially on a regional basis. For a global average, all climate models in the CMIP3 and CMIP5 show a robust weakening of tropical circulation, while observed changes in tropical circulation are inconsistent among data sets. A fundamental explanation for changes in tropical circulation is related to atmospheric stability. In a warmer climate, the upper troposphere warms up faster than the lower troposphere, so dry static stability increases. Thus, the atmosphere should become more stable and the corresponding tropical circulation weakens. However, a more physically-sound index, moist static stability, shows very scattering changes in global-warming simulations. In other words, the atmosphere can become either more stable or more unstable if considering the effect of water vapor. Here we introduce a new effect associated with convection depth by proposing another index, gross moist stability, to measure changes in atmospheric stability under global warming. The gross moist stability, an effective static stability, is vertical integral of the vertical gradient of moist static energy weighted by pressure velocity. It depends not only on the vertical gradient of dry static energy, which is equivalent to dry static stability, but also on moisture vertical distribution and convection depth. The effects of dry static energy and convection depth stabilize the atmosphere, while the moisture

  16. Circulation Condition of Two-component Bose-Einstein Condensate

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    In the report we point out that there exists an intrinsic difference in the internal symmetry of the two components spin-1/2 Bose condensates from that of spinor Bose condensates of the atoms with hyperfine states of nonzero integer-spins,which gives rise to a new topological constrain on the circulation for this two-component spin-1/2 Bose condensates.It is shown that the SU(2) symmetry of the spin-1/2 Bose condensate implies a

  17. [Patient with a Fontan circulation undergoing caesarean section: Anesthesiological management].

    Science.gov (United States)

    Schneck, E; Mann, V; Körner, C; Jost, A; Thul, J; Engel, J B; Müller, M F

    2015-07-01

    Adults suffering from congenital heart diseases (CHD) represent a challenge to anesthesiologists because of the diverse pathologies, complex pathophysiology and special treatment strategies. Due to improved therapeutic options for CHD, patient quality of life and life expectancy is increasing, leaving them as a growing population including pregnant patients with CHD. This article presents the main principles of the pathophysiology and anesthesiological management of pregnant patients living with a Fontan circulation based on a case report, which was complicated by an aortic coarctation and atonic uterine hemorrhage.

  18. Circulating placental proteins in pregnancies complicated by RH isoimmunization.

    Science.gov (United States)

    Lee, J N; Huang, S C; Ouyang, P C; Chard, T

    1984-07-01

    Nine pregnant women with Rh isoimmunization who delivered newborns with hydrops fetalis were studied. The placental proteins, pregnancy specific beta 1-glycoprotein (SP1), human placental lactogen, and placental protein 5 (PP5) were measured in maternal serum by radioimmunoassays. The results indicate that both the serum human placental lactogen and PP5 levels were significantly higher than those observed in normal pregnancy. The strikingly higher circulating PP5 levels found in all nine patients with Rh isoimmunization studied suggests that serum PP5 may be specifically elevated in pregnant patients with Rh isoimmunization and hydrops fetalis.

  19. Gasification of sawdust in pressurised internally circulating fluidized bed

    Energy Technology Data Exchange (ETDEWEB)

    Maartensson, R.; Lindblom, M. [Lund Univ. (Sweden). Dept. of Chemical Engineering

    1996-12-31

    A test plant for pressurised gasification of biofuels in a internally circulating fluidized bed has been built at the department of Chemical Engineering II at the University of Lund. The design performance is set to maximum 20 bar and 1 050 deg C at a thermal input of 100 kW or a maximum fuel input of 18 kg/in. The primary task is to study pressurised gasification of biofuels in relation to process requirements of the IGCC concept (integrated gasification combined cycle processes), which includes studies in different areas of hot gas clean-up in reducing atmosphere for gas turbine applications. (orig.)

  20. Uranus’ Hemispheric Asymmetries in Polar Cloud and Circulation Structures

    Science.gov (United States)

    Hammel, Heidi B.; Sromovsky, Lawrence; Fry, Pat; de Pater, Imke

    2015-11-01

    We report on the north polar region of Uranus in the post-equinoctial era. Near-IR imaging with Keck 2 using NIRC2 in 2012-2014 revealed numerous small bright features, as well as small dark features, between 50 degrees N and the north pole. Tracking of these features yielded circulation patterns, with the remarkable result that the region from 60 degrees to at least 83 degrees rotates about the northern pole as a solid body, with a drift rate of 4.1 degrees/hour westward relative to the interior (Sromovsky et al. 2015, Icarus 258, 192-223). For the south pole, the same latitude region had dramatically different characteristics, as judged by 1986 Voyager and 2003 Keck observations. The southern region showed no discrete near-IR features; detailed circulation measurements in that region were based solely on low-contrast features in re-analyzed Voyager images (Karkoschka, 2015, Icarus 250, 294-307). They revealed a large gradient in drift rates, with values reaching twice that seen in the corresponding northern region.The north-south asymmetry in circulation and cloud structure/morphology is surprising because the distribution of upper tropospheric methane is relatively symmetric: roughly constant over a region from 30 S to 30 N, and then declining at higher latitudes in both hemispheres. The methane distribution suggests symmetric down-welling motion in both polar regions, which would inhibit formation of condensation clouds there, in contrast to the observed dichotomy. Some asymmetry may be an effect of seasonal forcing, since the north versus south polar measurements were made during different seasons. If so, then major changes can be expected in the north polar region as Uranus proceeds toward its 2030 northern summer solstice. Hubble STIS observations expected in October of 2015 will further examine the vertical distribution and stability of the polar methane abundances. Future high-resolution imaging with Earth-based facilities will be able to track circulation

  1. Circulating docosahexaenoic acid levels are associated with fetal insulin sensitivity.

    Directory of Open Access Journals (Sweden)

    Jin-Ping Zhao

    Full Text Available BACKGROUND: Arachidonic acid (AA; C20∶4 n-6 and docosahexaenoic acid (DHA; C22∶6 n-3 are important long-chain polyunsaturated fatty acids (LC-PUFA in maintaining pancreatic beta-cell structure and function. Newborns of gestational diabetic mothers are more susceptible to the development of type 2 diabetes in adulthood. It is not known whether low circulating AA or DHA is involved in perinatally "programming" this susceptibility. This study aimed to assess whether circulating concentrations of AA, DHA and other fatty acids are associated with fetal insulin sensitivity or beta-cell function, and whether low circulating concentrations of AA or DHA are involved in compromised fetal insulin sensitivity in gestational diabetic pregnancies. METHODS AND PRINCIPAL FINDINGS: In a prospective singleton pregnancy cohort, maternal (32-35 weeks gestation and cord plasma fatty acids were assessed in relation to surrogate indicators of fetal insulin sensitivity (cord plasma glucose-to-insulin ratio, proinsulin concentration and beta-cell function (proinsulin-to-insulin ratio in 108 mother-newborn pairs. Cord plasma DHA levels (in percentage of total fatty acids were lower comparing newborns of gestational diabetic (n = 24 vs. non-diabetic pregnancies (2.9% vs. 3.5%, P = 0.01. Adjusting for gestational age at blood sampling, lower cord plasma DHA levels were associated with lower fetal insulin sensitivity (lower glucose-to-insulin ratio, r = 0.20, P = 0.036; higher proinsulin concentration, r = -0.37, P <0.0001. The associations remained after adjustment for maternal and newborn characteristics. Cord plasma saturated fatty acids C18∶0 and C20∶0 were negatively correlated with fetal insulin sensitivity, but their levels were not different between gestational diabetic and non-diabetic pregnancies. Cord plasma AA levels were not correlated with fetal insulin sensitivity. CONCLUSION: Low circulating DHA levels are associated with

  2. Sports training and circulating adipokine levels 

    Directory of Open Access Journals (Sweden)

    Ryszard Plinta

    2013-01-01

    Full Text Available  The beneficial effect of regular moderate physical activity on metabolic profile is well documented. Sedentary lifestyle is a risk factor of excessive visceral fat accumulation, insulin resistance, type 2 diabetes and cardiovascular disease development. However, intensive training in athletes may be related to unfavorable changes in secretion of adipose tissue hormones and constitute a link in the pathogenesis of hormonal disturbances observed in athletes.In this paper we review the recently published data concerning the impact of sports training on circulating adipokine levels in athletes.

  3. Ionometric determination of chloride ion in circulating and waste waters

    Energy Technology Data Exchange (ETDEWEB)

    Bebeshko, G.I.; Afanas' eva, V.I.; Danielova, I.I.; Dmitriev, M.A.; Radchenko, A.F.

    1986-09-01

    The authors attempt to develop selective ionometric methods to determine chloride ion in waste and circulating waters from technological ore processing, containing significant amounts of sulfide ion and various flotation reagents. These waters contain practically no cations that form hard to dissolve compounds with chloride ion such as Ag/sup +/, Cu/sup +/, Hg/sup +/ or Pb/sup 2 +/. The chloride ion concentration in water varies between 10 and 100 mg/liter. Information is shown on the concentration of the main anions and flotation reagents in waters that were analyzed.

  4. Contribution of Oceanic Circulation to the Poleward Heat Flux

    Institute of Scientific and Technical Information of China (English)

    HUANG Ruixin

    2005-01-01

    Oceanic contribution to the poleward heat flux in the climate system includes two components: the sensible heat flux and the latent heat flux. Although the latent heat flux has been classified as atmospheric heat flux exclusively, it is argued that oceanic control over this component of poleward heat flux should play a critically important role. The so-called swamp ocean model practice is analyzed in detail, and the critical role of oceanic circulation in the establishment of the meridional moisture transport is emphasized.

  5. A Study on Planetary Atmospheric Circulations using THOR

    Science.gov (United States)

    Mendonça, João; Grosheintz, Luc; Lukas Grimm, Simon; Heng, Kevin

    2015-12-01

    The large variety of planetary parameters observed leads us to think that exoplanets may show a large range of possible climates. It is therefore of the uttermost importance to investigate the influence of astronomical and planetary bulk parameters in driving the atmospheric circulations. In the solar system the results from planetary spacecraft missions have demonstrated how different the planetary climate and atmospheric circulations can be. The study of exoplanets will require probing a far wider range of physical and orbital parameters than the ones of our neighbor planets. For this reason, such a study will involve exploring an even larger diversity of circulation and climate regimes. Our new atmospheric model, THOR, is intended to be extremely flexible and to explore the large diversity of planetary atmospheres.THOR is part of the Exoclimes Simulation Platform, and is a project of the Exoplanet and Exoclimes Group (see www.exoclime.org). THOR solves the complex atmospheric fluid equations in a rotating sphere (fully compressible - nonhydrostatic system) using an icosahedral grid. The main advantages of using our new platform against other recent exoplanet models is that 1) The atmospheric fluid equations are completely represented and no approximations are used that could compromise the physics of the problem; 2) The model uses for the first time in exoplanet studies, a specific icosahedral grid that solves the pole problem; 3) The interface is user friendly and can be easily adapted to a multitude of atmospheric conditions; 4) By using GPU computation, our code greatly improves the typical code running time.We will present and discuss the first detailed results of our simulations, more specifically of two benchmark tests that are a representative sample of the large range of exoplanetary parameters: Earth-like conditions (the Held-Suarez test) and a tidally locked hot-Jupiter. THOR has successfully passed these tests and is able to determine the main

  6. Circulation of prions within dust on a scrapie affected farm.

    Science.gov (United States)

    Gough, Kevin C; Baker, Claire A; Simmons, Hugh A; Hawkins, Steve A; Maddison, Ben C

    2015-04-16

    Prion diseases are fatal neurological disorders that affect humans and animals. Scrapie of sheep/goats and Chronic Wasting Disease (CWD) of deer/elk are contagious prion diseases where environmental reservoirs have a direct link to the transmission of disease. Using protein misfolding cyclic amplification we demonstrate that scrapie PrP(Sc) can be detected within circulating dusts that are present on a farm that is naturally contaminated with sheep scrapie. The presence of infectious scrapie within airborne dusts may represent a possible route of infection and illustrates the difficulties that may be associated with the effective decontamination of such scrapie affected premises.

  7. Circulating MKRN3 levels decline during puberty in healthy boys

    DEFF Research Database (Denmark)

    Busch, Alexander S; Hagen, Casper P; Almstrup, Kristian;

    2016-01-01

    role of the protein on GnRH secretion. OBJECTIVE: To investigate peripubertal circulating MKRN3 levels in healthy boys Design: Population-based longitudinal study in healthy Danish boys Setting: General community Patients or Other Participants: Healthy boys (n = 60) aged [median (range)] 9.3 (5.8 - 11...... to pubertal onset support MKRN3 as an inhibitor of GnRH secretion during mid-childhood.......CONTEXT: Initiation and progression of puberty requires concerted action of hypothalamic activating and inhibiting factors. Recently, cases of familial central precocious puberty have been linked to loss-of-function mutations of makorin RING-finger protein 3 (MKRN3) indicating a pivotal inhibitory...

  8. The origin of circulating CD36 in type 2 diabetes

    OpenAIRE

    2013-01-01

    Objective: Elevated plasma levels of the fatty acid transporter, CD36, have been shown to constitute a novel biomarker for type 2 diabetes mellitus (T2DM). We recently reported such circulating CD36 to be entirely associated with cellular microparticles (MPs) and aim here to determine the absolute levels and cellular origin(s) of these CD36+MPs in persons with T2DM. Design: An ex vivo case-control study was conducted using plasma samples from 33 obese individuals with T2DM (body mass index (B...

  9. The Fontan circulation: a challenge to William Harvey?

    Science.gov (United States)

    de Leval, Marc R

    2005-04-01

    The Fontan operation, which places the systemic and pulmonary circulations in series and is driven by a single ventricular chamber, is the treatment of choice for patients born with one ventricle. Its introduction 35 years ago was the result of a flurry of experimental and clinical research that had started in the 1940s. A large number of children have benefited and continue to benefit from the Fontan operation, but there is a genuine concern that, despite the refinement of the surgical procedures in the past 20 years, continuing attrition might be inevitable. This adverse effect can lead to a decline in functional capacity, and premature late death.

  10. The discovery of pulmonary circulation: From Imhotep to William Harvey.

    Science.gov (United States)

    ElMaghawry, Mohamed; Zanatta, Alberto; Zampieri, Fabio

    2014-01-01

    In his quest to comprehend his existence, Man has long been exploring his outer world (macro-cosmos), as well as his inner world (micro-cosmos). In modern times, monmental advances in the fields of physics, chemistry, and other natural sciences have reflected on how we understand the anatomy and physiology of the human body and circulation. Yet, humanity took a long and winding road to reach what we acknowledge today as solid facts of cardiovascular physiology. In this article, we will review some of the milestones along this road.

  11. Single-cell analyses of circulating tumor cells

    Institute of Scientific and Technical Information of China (English)

    Xi-Xi Chen; Fan Bai

    2015-01-01

    Circulating tumor cells (CTCs) are a population of tumor cells mediating metastasis, which results in most of the cancer related deaths. hTe number of CTCs in the peripheral blood of patients is rare, and many platforms have been launched for detection and enrichment of CTCs. Enumeration of CTCs has already been used as a prognosis marker predicting the survival rate of cancer patients. Yet CTCs should be more potential. Studies on CTCs at single cell level may help revealing the underlying mechanism of tumorigenesis and metastasis. Though far from developed, this area of study holds much promise in providing new clinical application and deep understanding towards metastasis and cancer development.

  12. Computer Assisted Circulation Control at Health Sciences Library SUNYAB

    Directory of Open Access Journals (Sweden)

    Jean K. Miller

    1972-06-01

    Full Text Available A description of the circulation system which the Health Sciences Library at the State University of New York at Buffalo has been using since October 1970. Features of the system include automatic production of overdue, fine, and billing notices; notices for call-in of requested books; and book availability notices. Remote operation and processing on the IBM 360/40 and CDC 6400 computer are accomplished via the Administrative Terminal System (ATS and Terminal job Entry (T]E. The system provides information for management of the collection and improved service to the user.

  13. Deliberate interventions in the availability and circulation of practice elements

    DEFF Research Database (Denmark)

    Quitzau, Maj-Britt; Hoffmann, Birgitte

    of practices can help to inform policy makers in this regard, there is a need for more detailed insight into how such deliberate interventions are performed in practice and intersect with the availability and circulation of practice elements, among others. The aim of this paper is to explore the considerations...... process became a very traditional building structure with more insulation and with an individual heating system combining a heat-pump with either solar or geothermal heating. The obtained building design merely led to changes in some of the practice elements, like new technologies and new maintenance...

  14. Water immersion and changes in the foetoplacental and uteroplacental circulation

    DEFF Research Database (Denmark)

    Thisted, Dorthe Louise Ahrenkiel; Nørgaard, Lone Nikoline; Meyer, Helle Mølgaard;

    2015-01-01

    Abstract Objective: To evaluate the effect of immersion into water on maternal blood pressure, amount of amniotic fluid and on the foetoplacental- and uteroplacental circulation in healthy women with an uncomplicated singleton pregnancy. Methods: Twenty-five healthy women were included. Recordings...... of blood pressure, deepest vertical pocket of amniotic fluid and pulsatility index (PI) measured by Doppler in the umbilical and uterine arteries were obtained. The participants were immersed into water and the measurements were repeated after 5 and 25 min in water and again 15 and 30 min post immersion....... Results: The amount of amniotic fluid increased significantly (p 

  15. Nonequilibrium steady-state circulation and heat dissipation functional.

    Science.gov (United States)

    Qian, H

    2001-08-01

    A nonequilibrium steady-state (NESS), different from an equilibrium, is sustained by circular balance rather than detailed balance. The circular fluxes are driven by energy input and heat dissipation, accompanied by a positive entropy production. Based on a Master equation formalism for NESS, we show the circulation is intimately related to the recently studied Gallavotti-Cohen symmetry of heat dissipation functional, which in turn suggests a Boltzmann's formulalike relation between rate constants and energy in NESS. Expanding this unifying view on NESS to diffusion is discussed.

  16. Analysis of circulating microRNAs in adrenocortical tumors.

    Science.gov (United States)

    Szabó, Diana Rita; Luconi, Michaela; Szabó, Peter M; Tóth, Miklós; Szücs, Nikolette; Horányi, János; Nagy, Zoltán; Mannelli, Massimo; Patócs, Attila; Rácz, Károly; Igaz, Peter

    2014-03-01

    Differential diagnosis of adrenocortical adenoma (ACA) and carcinoma is of pivotal clinical relevance, as the prognosis and clinical management of benign and malignant adrenocortical tumors (ACTs) is entirely different. Circulating microRNAs (miRNAs) are promising biomarker candidates of malignancy in several tumors; however, there are still numerous technical problems associated with their analysis. The objective of our study was to investigate circulating miRNAs in ACTs and to evaluate their potential applicability as biomarkers of malignancy. We have also addressed technical questions including the choice of profiling and reference gene used. A total of 25 preoperative plasma samples obtained from patients with ACAs and carcinomas were studied by microarray and quantitative real-time PCR. None of the three miRNAs (hsa-miR-192, hsa-mir-197 and hsa-miR-1281) found as differentially expressed in plasma samples in our microarray screening could be validated by quantitative real-time PCR. In contrast, of the selected eight miRNAs reported in the literature as differentially expressed in ACT tissues, five (hsa-miR-100, hsa-miR-181b, hsa-miR-184, hsa-miR-210 and hsa-miR-483-5p) showed a statistically significant overexpression in adrenocortical cancer vs adenoma when normalized on hsa-miR-16 as a reference gene. Receiver operator characteristic analysis of data revealed that the combination of dCThsa-miR-210 - dCThsa-miR-181b and dCThsa-miR-100/dCThsa-miR-181b showed the highest diagnostic accuracy (area under curve 0.87 and 0.85, respectively). In conclusion, we have found significant differences in expression of circulating miRNAs between ACAs and carcinomas, but their diagnostic accuracy is not yet high enough for clinical application. Further studies on larger cohorts of patients are needed to assess the diagnostic and prognostic potential application of circulating miRNA markers.

  17. World Ocean Circulation Experiment (WOCE) Young Investigator Workshops

    Science.gov (United States)

    Austin, Meg

    2004-01-01

    The World Ocean Circulation Experiment (WOCE) Young Investigator Workshops goals and objectives are: a) to familiarize Young Investigators with WOCE models, datasets and estimation procedures; b) to offer intensive hands-on exposure to these models ard methods; c) to build collaborations among junior scientists and more senior WOCE investigators; and finally, d) to generate ideas and projects leading to fundable WOCE synthesis projects. To achieve these goals and objectives, the Workshop will offer a mixture of tutorial lectures on numerical models and estimation procedures, advanced seminars on current WOCE synthesis activities and related projects, and the opportunity to conduct small projects which put into practice the techniques advanced in the lectures.

  18. NUCLA Circulating Atmospheric Fluidized Bed Demonstration Project. Annual report, 1988

    Energy Technology Data Exchange (ETDEWEB)

    1991-01-01

    This Annual Report on Colorado-Ute Electric Association`s NUCLA Circulating Fluidized Bed (CFB) Demonstration Program covers the period from February 1987 through December 1988. The outline for presentation in this report includes a summary of unit operations along with individual sections covering progress in study plan areas that commenced during this reporting period. These include cold-mode shakedown and calibration, plant commercial performance statistics, unit start-up (cold), coal and limestone preparation and handling, ash handling system performance and operating experience, tubular air heater, baghouse operation and performance, materials monitoring, and reliability monitoring. During this reporting period, the coal-mode shakedown and calibration plan was completed. (VC)

  19. Results of theoretical and experimental studies of hydrodynamics of circulation loops in circulating fluidized bed reactors and systems with interconnected reactors

    Science.gov (United States)

    Ryabov, G. A.; Folomeev, O. M.; Sankin, D. A.; Melnikov, D. A.

    2015-02-01

    Problems of the calculation of circulation loops in circulating fluidized bed reactors and systems with interconnected reactors (polygeneration systems for the production of electricity, heat, and useful products and chemical cycles of combustion and gasification of solid fuels)are considered. A method has been developed for the calculation of circulation loop of fuel particles with respect to boilers with circulating fluidized bed (CFB) and systems with interconnected reactors with fluidized bed (FB) and CFB. New dependences for the connection between the fluidizing agent flow (air, gas, and steam) and performance of reactors and for the whole system (solids flow rate, furnace and cyclone pressure drops, and bed level in the riser) are important elements of this method. Experimental studies of hydrodynamics of circulation loops on the aerodynamic unit have been conducted. Experimental values of pressure drop of the horizontal part of the L-valve, which satisfy the calculated dependence, have been obtained.

  20. Changes in the strength and width of the Hadley circulation since 1871

    Directory of Open Access Journals (Sweden)

    J. Liu

    2012-03-01

    Full Text Available Recent studies demonstrate that the Hadley Circulation has intensified and expanded for the past three decades, which has important implications for subtropical societies and may lead to profound changes in global climate. However, the robustness of this intensification and expansion that should be considered when interpreting long-term changes of the Hadley Circulation is still matters of debate. It also remains largely unknown how the Hadley Circulation has evolved over longer periods. Here we present long-term variability of the Hadley Circulation using the 20th Century Reanalysis. It shows a slight strengthening and widening of the Hadley Circulation since the late 1970s, which is not inconsistent with recent assessments. However, over centennial timescales (1871–2008, the Hadley Circulation shows a tendency towards more intense and narrower state. More importantly, the width of the Hadley Circulation has not yet completed a life-cycle since 1871. The strength and width of the Hadley Circulation during the late 19th and early 20th century show strong natural variability, exceeding variability that coincides with global warming in recent decades. These findings raise the question that the recent change of the Hadley Circulation is primarily attributed to greenhouse warming or a long-period oscillation of the Hadley Circulation substantially longer than that observed in previous studies.

  1. Normothermal or Hypothermal Extracorporeal Circulation Regimens in Patients with Acquired Heart Disease

    Directory of Open Access Journals (Sweden)

    V. V. Lomivorotov

    2013-01-01

    Full Text Available Background. Hypothermal extracorporeal circulation has been used in cardiosurgery over 50 years. However, recent trials have not shown its predominant effect on the protection of the brain, lung, and myocardium in patients during surgery. We have presumed that when normothermal extracorporeal circulation used in patients with acquired heart disease, its pathophysiological effect on the body is comparable with that of hypothermal extracorporeal circulation. Subjects and methods. One hundred and forty patients who were to undergo acquired heart disease correction were randomized into two equal groups: that using hypothermal or normothermal extracorporeal circulation. Perioperative troponin I and NT-proBNP concentrations, postoperative clinical course, and hospital morbidity and mortality rates were estimated. Results. There were no significant differences in the concentrations of troponin I and NT-proBNP at the study stages. In the normothermal extracorporeal circulation group patients with isolated aortic stenosis, the concentration of troponin I was higher than that in the hypothermal extracorporeal circulation group. Analyzing the postoperative course indicated that the duration of mechanical ventilation was significantly lower in the hypothermal extracorporeal circulation group than in the normothermal extracorporeal circulation group. There were no differences in hospital complications and mortality rates. Conclusion. Hypothermal versus normothermal extracorporeal circulation in the correction of acquired heart diseases has no predominant effect on tro-ponin I and NT-proBNP concentrations, postoperative clinical course, and hospital complications and mortality rates. Key words: extracorporeal circulation, hypothermia, acquired heart disease, troponin I, NT-proBNP.

  2. Nanobiotechnology for the capture and manipulation of circulating tumor cells.

    Science.gov (United States)

    Hughes, Andrew D; King, Michael R

    2012-01-01

    A necessary step in metastasis is the dissemination of malignant cells into the bloodstream, where cancer cells travel throughout the body as circulating tumor cells (CTC) in search of an opportunity to seed a secondary tumor. CTC represent a valuable diagnostic tool: evidence indicates that the quantity of CTC in the blood has been shown to relate to the severity of the illness, and samples are readily obtained through routine blood draws. As such, there has been a push toward developing technologies to reliably detect CTC using a variety of molecular and immunocytochemical techniques. In addition to their use in diagnostics, CTC detection systems that isolate CTC in such a way that the cells remain viable will allow for the performance of live-cell assays to facilitate the development of personalized cancer therapies. Moreover, techniques for the direct manipulation of CTC in circulation have been developed, intending to block metastasis in situ. We review a number of current and emerging micro- and nanobiotechnology approaches for the detection, capture, and manipulation of rare CTC aimed at advancing cancer treatment.

  3. 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...

  4. Genetic engineering of platelets to neutralize circulating tumor cells.

    Science.gov (United States)

    Li, Jiahe; Sharkey, Charles C; Wun, Brittany; Liesveld, Jane L; King, Michael R

    2016-04-28

    Mounting experimental evidence demonstrates that platelets support cancer metastasis. Within the circulatory system, platelets guard circulating tumor cells (CTCs) from immune elimination and promote their arrest at the endothelium, supporting CTC extravasation into secondary sites. Neutralization of CTCs in blood circulation can potentially attenuate metastases to distant organs. Therefore, extensive studies have explored the blockade of platelet-CTC interactions as an anti-metastatic strategy. Such an intervention approach, however, may cause bleeding disorders since the platelet-CTC interactions inherently rely on the blood coagulation cascade including platelet activation. On the other hand, platelets have been genetically engineered to correct inherited bleeding disorders in both animal models and human clinical trials. In this study, inspired by the physical association between platelets and CTCs, platelets were genetically modified to express surface-bound tumor necrosis factor-related apoptosis-inducing ligand (TRAIL), a cytokine known to induce apoptosis specifically in tumor cells. The TRAIL-expressing platelets were demonstrated to kill cancer cells in vitro and significantly reduce metastases in a mouse model of prostate cancer metastasis. Our results suggest that using platelets to produce and deliver cancer-specific therapeutics can provide a Trojan-horse strategy of neutralizing CTCs to attenuate metastasis.

  5. 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.

  6. Analysis of hallucinogenic constituents in Amanita mushrooms circulated in Japan.

    Science.gov (United States)

    Tsujikawa, Kenji; Mohri, Hiroyuki; Kuwayama, Kenji; Miyaguchi, Hajime; Iwata, Yuko; Gohda, Akinaga; Fukushima, Sunao; Inoue, Hiroyuki; Kishi, Tohru

    2006-12-20

    The constituents of seven mushrooms sold as Amanita muscaria or Amanita pantherina (five A. muscaria and two A. pantherina) and four "extracts purported to contain A. muscaria" products that are currently circulated in Japan were determined. All mushroom samples were identified as A. muscaria or A. pantherina by macroscopic and microscopic observation. The dissociative constituents, ibotenic acid (IBO) and muscimol (MUS), were extracted with 70% methanol twice and determined by gas chromatography/mass spectrometry. The IBO (as the hydrate)/MUS contents were in the range of muscaria and 188-269ppm/1554-1880ppm in the cap of A. pantherina. In the caps, these compounds had a tendency to be more concentrated in the flesh than in the cuticle. On the other hand, the IBO/MUS contents in the stem were far lower than in the caps. In the "extracts purported to contain A. muscaria" products, IBO/MUS were detected below the lower limit of calibration curve (Amanita mushrooms that are circulated in the drug market.

  7. Radial Transport and Meridional Circulation in Accretion Disks

    Science.gov (United States)

    Philippov, Alexander A.; Rafikov, Roman R.

    2017-03-01

    Radial transport of particles, elements and fluid driven by internal stresses in three-dimensional (3D) astrophysical accretion disks is an important phenomenon, potentially relevant for the outward dust transport in protoplanetary disks, origin of the refractory particles in comets, isotopic equilibration in the Earth–Moon system, etc. To gain better insight into these processes, we explore the dependence of meridional circulation in 3D disks with shear viscosity on their thermal stratification, and demonstrate a strong effect of the latter on the radial flow. Previous locally isothermal studies have normally found a pattern of the radial outflow near the midplane, switching to inflow higher up. Here we show, both analytically and numerically, that a flow that is inward at all altitudes is possible in disks with entropy and temperature steeply increasing with height. Such thermodynamic conditions may be typical in the optically thin, viscously heated accretion disks. Disks in which these conditions do not hold should feature radial outflow near the midplane, as long as their internal stress is provided by the shear viscosity. Our results can also be used for designing hydrodynamical disk simulations with a prescribed pattern of the meridional circulation.

  8. Option contracts in fresh produce supply chain with circulation loss

    Directory of Open Access Journals (Sweden)

    Chong Wang

    2013-03-01

    Full Text Available Purpose: The purpose of this paper is to investigate management decisions via option contracts in a two-stage supply chain in which a fresh produce supplier sells to a retailer, considering the circulation loss of the fresh produce. Design/methodology/approach: Authors propose a Stackelberg model to analyze the supply chain members’ decisions in the decentralized supply chain compared with the integrated one under the newsvendor framework. Findings: The results illustrate that there exists a unique optimal option order quantity for the retailer and a unique optimal option order price for the supplier giving certain conditions; furthermore, option contracts cannot coordinate the fresh produce supply chain when the retailer only orders options. Originality/value: Agricultural products especially fresh produce’s characteristics such as circulation loss and high risk are considered. Option contracts and game theory are combined to manage the fresh produce supply chain’s risk. The proposed tool and models are hoped to shed light to the future works in the field of supply chain risk management.

  9. The Challenges of Detecting Circulating Tumor Cells in Sarcoma

    Science.gov (United States)

    Tellez-Gabriel, Marta; Brown, Hannah K.; Young, Robin; Heymann, Marie-Françoise; Heymann, Dominique

    2016-01-01

    Sarcomas are a heterogeneous group of malignant neoplasms of mesenchymal origin, many of which have a propensity to develop distant metastases. Cancer cells that have escaped from the primary tumor are able to invade into surrounding tissues, to intravasate into the bloodstream to become circulating tumor cells (CTCs), and are responsible for the generation of distant metastases. Due to the rarity of these tumors and the absence of specific markers expressed by sarcoma tumor cells, the characterization of sarcoma CTCs has to date been relatively limited. Current techniques for isolating sarcoma CTCs are based on size criteria, the identification of circulating cells that express either common mesenchymal markers, sarcoma-specific markers, such as CD99, CD81, or PAX3, and chromosomal translocations found in certain sarcoma subtypes, such as EWS-FLI1 in Ewing’s sarcoma, detection of osteoblast-related genes, or measurement of the activity of specific metabolic enzymes. Further studies are needed to improve the isolation and characterization of sarcoma CTCs, to demonstrate their clinical significance as predictive and/or prognostic biomarkers, and to utilize CTCs as a tool for investigating the metastatic process in sarcoma and to identify novel therapeutic targets. The present review provides a short overview of the most recent literature on CTCs in sarcoma. PMID:27656422

  10. Continuous circulation apparatus for air drilling well bore operations

    Energy Technology Data Exchange (ETDEWEB)

    Stallings, J.L.

    1982-02-16

    An apparatus is disclosed for maintaining a continuous supply of air pressure downhole during a well bore drilling operation, even during the addition of a pipe section to the drill string. It consists of a housing installed at the surface of the well at the position of the drilling equipment wherein the upper end of the drill string is separated from the drive mechanism in order that a new piece of drill pipe may be added to the drill string, a flapper or closure member pivotally secured within the housing normally held in an open position by the outer periphery of the drill string and spring urged in a direction toward the open end of the sleeve through which the drive mechanism passes when the drive mechanism has been backed off or removed for the addition of a section of pipe to the drill string, and a by-pass line in communication with the interior of the housing for directing air pressure from the air supply to the housing when the flapper member is in the closed position whereby the air pressure may be circulated downwardly through the drill string for maintaining the air circulation downhole during the entire drilling operation.

  11. Titan's post-equinox circulation revealed using chemical tracers

    Science.gov (United States)

    Teanby, N. A.; Irwin, P. G. J.; Nixon, C. A.; de Kok, R.; Vinatier, S.; Coustenis, A.; Calcutt, S. B.

    2012-04-01

    Titan’s atmosphere harbors a vast array of minor chemical compounds produced by its active photochemical cycle - including many hydrocarbon and nitrile species. These species have a wide range of lifetimes and can be used as chemical tracers of atmospheric motion on a variety of time scales (Teanby et al 2008). Therefore, by measuring how the abundances of these species vary during Cassini’s mission so far, it is possible to probe changes in Titan’s general circulation. Here we use eight years of Cassini Composite InfraRed Spectrometer (CIRS) data to study how the atmospheric circulation behaves during the equinox and post-equinox periods. As northern winter progressed to northern spring, significant changes in the distribution of trace gases were observed. These include an increase in trace gas abundance at the north pole and northward migration of the vortex boundary. The implications of the observed changed will be discussed - including a possible interpretation of the recent changes as a weakening of the north polar vortex accompanied by a reduction in cross-vortex mixing. References: Teanby, N. A., et al. (2008) "Titan's winter polar vortex structure revealed by chemical tracers". JGR-Planets, Vol. 113, E12003. Figure showing the observed variations in temperature and composition from the mission so far.

  12. Low density lipoproteins as circulating fast temperature sensors.

    Directory of Open Access Journals (Sweden)

    Ruth Prassl

    Full Text Available BACKGROUND: The potential physiological significance of the nanophase transition of neutral lipids in the core of low density lipoprotein (LDL particles is dependent on whether the rate is fast enough to integrate small (+/-2 degrees C temperature changes in the blood circulation. METHODOLOGY/PRINCIPAL FINDINGS: Using sub-second, time-resolved small-angle X-ray scattering technology with synchrotron radiation, we have monitored the dynamics of structural changes within LDL, which were triggered by temperature-jumps and -drops, respectively. Our findings reveal that the melting transition is complete within less than 10 milliseconds. The freezing transition proceeds slowly with a half-time of approximately two seconds. Thus, the time period over which LDL particles reside in cooler regions of the body readily facilitates structural reorientation of the apolar core lipids. CONCLUSIONS/SIGNIFICANCE: Low density lipoproteins, the biological nanoparticles responsible for the transport of cholesterol in blood, are shown to act as intrinsic nano-thermometers, which can follow the periodic temperature changes during blood circulation. Our results demonstrate that the lipid core in LDL changes from a liquid crystalline to an oily state within fractions of seconds. This may, through the coupling to the protein structure of LDL, have important repercussions on current theories of the role of LDL in the pathogenesis of atherosclerosis.

  13. Asymmetric dimethylarginine in the maternal and fetal circulation in preeclampsia.

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    Braekke, Kristin; Ueland, Per M; Harsem, Nina K; Staff, Anne Cathrine

    2009-10-01

    Preeclampsia is a leading cause of intrauterine growth restriction and preterm birth. Endothelial dysfunction is the common final pathway leading to clinical signs of preeclampsia including hypertension and proteinuria. Asymmetric dimethylarginine (ADMA) is an endogenous inhibitor of NOS and induces endothelial dysfunction by reversibly inhibiting NO production from l-arginine. The purpose of this study was to investigate maternal and fetal concentrations of ADMA, l-arginine, and symmetric dimethylarginine (SDMA). Women with preeclampsia (n = 47) and controls (n = 51) who gave birth by cesarean section were included in the study. We analyzed the maternal plasma and umbilical vein and artery plasma. We found that not only maternal concentrations of ADMA and SDMA but also l-arginine were significantly higher in women with preeclampsia than in controls. In fetal samples, only SDMA concentrations were higher in the preeclampsia group than in controls. The median ADMA concentration was three times higher in the fetal circulation than in the maternal circulation, but there was no difference between the preeclampsia group and the control group, and the veno-arterious gradient indicated that the placenta was the source of ADMA.

  14. Regulation of the pulmonary circulation in the fetus and newborn.

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    Gao, Yuansheng; Raj, J Usha

    2010-10-01

    During the development of the pulmonary vasculature in the fetus, many structural and functional changes occur to prepare the lung for the transition to air breathing. The development of the pulmonary circulation is genetically controlled by an array of mitogenic factors in a temporo-spatial order. With advancing gestation, pulmonary vessels acquire increased vasoreactivity. The fetal pulmonary vasculature is exposed to a low oxygen tension environment that promotes high intrinsic myogenic tone and high vasocontractility. At birth, a dramatic reduction in pulmonary arterial pressure and resistance occurs with an increase in oxygen tension and blood flow. The striking hemodynamic differences in the pulmonary circulation of the fetus and newborn are regulated by various factors and vasoactive agents. Among them, nitric oxide, endothelin-1, and prostaglandin I(2) are mainly derived from endothelial cells and exert their effects via cGMP, cAMP, and Rho kinase signaling pathways. Alterations in these signaling pathways may lead to vascular remodeling, high vasocontractility, and persistent pulmonary hypertension of the newborn.

  15. Nonrandom distribution of iron in circulating human transferrin.

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    Zak, O; Aisen, P

    1986-07-01

    By combining the urea gel electrophoresis technique of Makey and Seal with Western immunoblotting, a method has been developed for analyzing the distribution of iron between the two sites of circulating human transferrin. The new method avoids exposure of samples to a nonphysiologic pH that may promote removal or redistribution of iron from the protein; this facilitates examination of multiple samples at one time. Analysis of 21 freshly drawn specimens from normal human subjects confirms previous reports that iron is not randomly distributed in the specific sites of transferrin. Rather, there is a considerable range in the ratio of occupancies of N-terminal and C-terminal sites (N:C ratio), from 0.31 to 6.87 in the present study, with the N-terminal site predominantly occupied in most subjects. The N:C ratio correlates modestly with serum iron concentration (r = .54). Possible flaws in studies indicating a random occupancy of the specific sites of circulating transferrin may lie in the low pH to which samples may be exposed during procedures based on isoelectric focusing or in drawing inferences from data considering only total monoferric transferrin rather than the two distinguishable monoferric species.

  16. Drivers of uncertainty in simulated ocean circulation and heat uptake

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    Huber, Markus B.; Zanna, Laure

    2017-02-01

    The impact of uncertainties in air-sea fluxes and ocean model parameters on the ocean circulation and ocean heat uptake (OHU) is assessed in a novel modeling framework. We use an ocean-only model forced with the simulated sea surface fields of the CMIP5 climate models. The simulations are performed using control and 1% CO2 warming scenarios. The ocean-only ensemble adequately reproduces the mean Atlantic Meridional Overturning Circulation (AMOC) and the zonally integrated OHU. The ensemble spread in AMOC strength, its weakening, and Atlantic OHU due to different air-sea fluxes is twice as large as the uncertainty range related to vertical and mesocale eddy diffusivities. The sensitivity of OHU to uncertainties in air-sea fluxes and model parameters differs vastly across basins, with the Southern Ocean exhibiting strong sensitivity to air-sea fluxes and model parameters. This study clearly demonstrates that model biases in air-sea fluxes are one of the key sources of uncertainty in climate simulations.

  17. Posterior circulation ischemic stroke following Russell′s viper envenomation

    Directory of Open Access Journals (Sweden)

    Siddalingana Gouda

    2011-01-01

    Full Text Available Ischemic stroke following viper bite is rare. We report a case of posterior circulation ischemic infarction following viper bite in a previously healthy woman. Soon after being bitten by the snake on the left leg, she developed local redness, echymosis and one hour later became drowsy. On examination she had skew deviation of eyes and down gaze preference, generalized hypotonia. A CT scan of brain showed infarcts in cerebellar hemispheres and occipital lobes on both sides and that was confirmed on magnetic resonance imaging of brain. Her coagulation profile was deranged. Most common and serious central nervous system complication following snake bite is intracranial hemorrhage. Ischemic stroke commonly involves anterior circulation. Bilateral cerebellar and occipital infraction is not yet reported in literature. Exact cause for the development of infarction is not clear. The possible mechanisms of infarction in this scenario are discussed. Patient was treated with anti-snake venom and showed a good recovery. Early imaging and early treatment with anti-snake venom is important for a favorable outcome.

  18. A comparative Study of Circulation Patterns at Active Lava Lakes

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    Lev, Einat; Oppenheimer, Clive; Spampinato, Letizia; Hernandez, Pedro; Unglert, Kathi

    2016-04-01

    Lava lakes present a rare opportunity to study magma dynamics in a large scaled-up "crucible" and provide a unique natural laboratory to ground-truth dynamic models of magma circulation. The persistence of lava lakes allows for long-term observations of flow dynamics and of lava properties, especially compared to surface lava flows. There are currently five persistent lava lakes in the world: Halemaumau in Kilauea (Hawaii, USA), Erta Ale (Ethiopia), Nyiragongo (Congo), Erebus (Antarctica), and Villarica (Chile). Marum and Benbow craters of Ambrym volcano (Vanuatu) and Masaya (Nicaragua) have often hosted lava lakes as well. We use visible-light and thermal infrared time-lapse and video footage collected at all above lakes (except Villarica, where the lake is difficult to observe), and compare the circulation patterns recorded. We calculate lake surface motion from the footage using the optical flow method (Lev et al., 2012) to produce 2D velocity fields. We mined both the surface temperature field and the surface velocity field for patterns using machine learning techniques such as "self-organizing maps (SOMs)" and "principle component analysis (PCA)". We use automatic detection technique to study the configuration of crustal plates at the lakes' surface. We find striking differences among the lakes, in flow direction, flow speed, frequency of changes in flow direction and speed, location and consistency of upwelling and downwelling, and crustal plate configuration. We relate the differences to lake size, shallow conduit geometry, lava viscosity, crystal and gas content, and crust integrity.

  19. Alemtuzumab treatment alters circulating innate immune cells in multiple sclerosis

    Science.gov (United States)

    Ahmetspahic, Diana; Ruck, Tobias; Schulte-Mecklenbeck, Andreas; Schwarte, Kathrin; Jörgens, Silke; Scheu, Stefanie; Windhagen, Susanne; Graefe, Bettina; Melzer, Nico; Klotz, Luisa; Arolt, Volker; Wiendl, Heinz; Meuth, Sven G.

    2016-01-01

    Objective: To characterize changes in myeloid and lymphoid innate immune cells in patients with relapsing-remitting multiple sclerosis (MS) during a 6-month follow-up after alemtuzumab treatment. Methods: Circulating innate immune cells including myeloid cells and innate lymphoid cells (ILCs) were analyzed before and 6 and 12 months after onset of alemtuzumab treatment. Furthermore, a potential effect on granulocyte-macrophage colony-stimulating factor (GM-CSF) and interleukin (IL)–23 production by myeloid cells and natural killer (NK) cell cytolytic activity was determined. Results: In comparison to CD4+ T lymphocytes, myeloid and lymphoid innate cell subsets of patients with MS expressed significantly lower amounts of CD52 on their cell surface. Six months after CD52 depletion, numbers of circulating plasmacytoid dendritic cells (DCs) and conventional DCs were reduced compared to baseline. GM-CSF and IL-23 production in DCs remained unchanged. Within the ILC compartment, the subset of CD56bright NK cells specifically expanded under alemtuzumab treatment, but their cytolytic activity did not change. Conclusions: Our findings demonstrate that 6 months after alemtuzumab treatment, specific DC subsets are reduced, while CD56bright NK cells expanded in patients with MS. Thus, alemtuzumab specifically restricts the DC compartment and expands the CD56bright NK cell subset with potential immunoregulatory properties in MS. We suggest that remodeling of the innate immune compartment may promote long-term efficacy of alemtuzumab and preserve immunocompetence in patients with MS. PMID:27766281

  20. Specific circulating immune complexes in acute chagas' disease

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    Ricardo Corral

    1987-02-01

    Full Text Available The presence of circulating immune complexes formed by IgM and IgG (CIC-IgM and CIC-IgG was investigated, using antigen-specific enzyme-immunoassays (ELISA, in 30 patients with acute Chagas' disease who showed parasitemia and inoculation chagoma. Control population consisted of patients with chronic T. cruzi infection (30, acute toxoplasmosis 10, leishmaniasis (8, rheumatoid arthritis (3 and healthy individuals with negative serology for Chagas* disease (30. Acute chagasic patients were 100% CIC-IgG and 96.66% CIC-IgM positive whereas immunofluorescence tests yielded 90% and 86.66% of positivity for specific IgG and IgM antibodies, respectively. Chronic patients were 68% CIC-IgG and 0% CIC-IgM positive. The 30 negative and the 21 cross-reaction controls proved negative for ELISA (CIC-IgM and CIC-IgG. The high sensitivity of ELISA assays would allow early immunologic diagnosis, as well as prompt treatment, of acute T. cruzi infection, thus eliminating the problem of the false-positive and false-negative results which affects traditional methods for detection of circulating antibodies.