Science.gov

Sample records for natural circulation phenomenon

  1. Radioactivity: A Natural Phenomenon.

    ERIC Educational Resources Information Center

    Ronneau, C.

    1990-01-01

    Discussed is misinformation people have on the subject of radiation. The importance of comparing artificial source levels of radiation to natural levels is emphasized. Measurements of radioactivity, its consequences, and comparisons between the risks induced by radiation in the environment and from artificial sources are included. (KR)

  2. Radioactivity: A Natural Phenomenon.

    ERIC Educational Resources Information Center

    Ronneau, C.

    1990-01-01

    Discussed is misinformation people have on the subject of radiation. The importance of comparing artificial source levels of radiation to natural levels is emphasized. Measurements of radioactivity, its consequences, and comparisons between the risks induced by radiation in the environment and from artificial sources are included. (KR)

  3. Religion as a Natural Phenomenon

    ScienceCinema

    Dennett, Daniel [Tufts University, Boston, Massachusetts, United States

    2016-07-12

    Religion is a costly human activity that has evolved over the millennia. Why does it exist and how does it foster such powerful allegiances? To undertake a serious scientific study of religious practices and attitudes we must set aside a traditional exemption from scrutiny which religions have enjoyed. Religious adherents may not welcome this attention, but we should press ahead with it, since if we don't come to understand religion as a natural phenomenon, our attempts to deal with the problems that loom in the twenty-first century will likely be counterproductive.

  4. Religion as a Natural Phenomenon

    SciTech Connect

    Dennett, Daniel

    2006-02-15

    Religion is a costly human activity that has evolved over the millennia. Why does it exist and how does it foster such powerful allegiances? To undertake a serious scientific study of religious practices and attitudes we must set aside a traditional exemption from scrutiny which religions have enjoyed. Religious adherents may not welcome this attention, but we should press ahead with it, since if we don't come to understand religion as a natural phenomenon, our attempts to deal with the problems that loom in the twenty-first century will likely be counterproductive.

  5. Religion as a Natural Phenomenon

    SciTech Connect

    Dennett, Daniel

    2006-02-15

    Religion is a costly human activity that has evolved over the millennia. Why does it exist and how does it foster such powerful allegiances? To undertake a serious scientific study of religious practices and attitudes we must set aside a traditional exemption from scrutiny which religions have enjoyed. Religious adherents may not welcome this attention, but we should press ahead with it, since if we don't come to understand religion as a natural phenomenon, our attempts to deal with the problems that loom in the twenty-first century will likely be counterproductive.

  6. Quenching phenomena in natural circulation loop

    SciTech Connect

    Umekawa, Hisashi; Ozawa, Mamoru; Ishida, Naoki

    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.

  7. Independent review of SCDAP/RELAP5 natural circulation calculations

    SciTech Connect

    Martinez, G.M.; Gross, R.J.; Martinez, M.J.; Rightley, G.S.

    1994-01-01

    A review and assessment of the uncertainties in the calculated response of reactor coolant system natural circulation using the SCDAP/RELAP5 computer code were completed. The SCDAP/RELAP5 calculation modeled a station blackout transient in the Surry nuclear power plant and concluded that primary system depressurization from natural circulation induced primary system failure is more likely than previously thought.

  8. Children's Independent Exploration of a Natural Phenomenon by Using a Pictorial Computer-Based Simulation.

    ERIC Educational Resources Information Center

    Kangassalo, Marjatta

    Using a pictorial computer simulation of a natural phenomenon, children's exploration processes and their construction of conceptual models were examined. The selected natural phenomenon was the variations of sunlight and heat of the sun experienced on the earth in relation to the positions of the earth and sun in space, and the subjects were…

  9. THE NATURE OF THE TOXIN-ANTITOXIN FLOCCULATION PHENOMENON

    PubMed Central

    Bronfenbrenner, J. J.; Reichert, Philip

    1926-01-01

    1. Animals immunized with the formalinized filtrates of young toxic cultures of B. botulinus produce an antitoxic serum poor in precipitins. 2. Animals immunized with the formalinized filtrates of old and partly autolyzed toxic cultures produce an antitoxic serum containing precipitins. 3. Animals immunized with toxin-free autolyzed bacteria produce a serum free from antitoxin but rich in specific precipitins. 4. Animals immunized with the filtrates of an atoxic variant produce a serum free from antitoxin but rich in precipitins for the homologous toxin. 5. Animals immunized with the washed bacteria of the atoxic variant produce a serum that contains no antitoxin, but is rich in precipitins for the homologous toxin. 6. Removal of the precipitins by flocculation with a non-toxic antigen does not materially reduce the antitoxic value of a serum. 7. Removal of the proteins of the antigen by add coagulation removes the specific precipitable substance. 8. All the sera that contain precipitins produce the specific flocculus when combined with homologous toxins, anatoxins, or with the filtrates of the atoxic variant. The flocculation is restricted within the type. The amount of the precipitate and the width of the zone vary approximately with the estimated amount of bacterial protein in the antigen that is used for the immunization of animals. We conclude, therefore, that the toxin-antitoxin flocculation is a specific bacterial precipitation phenomenon. PMID:19869206

  10. Code-Switching: A Natural Phenomenon vs Language "Deficiency."

    ERIC Educational Resources Information Center

    Cheng, Li-Rong; Butler, Katharine

    1989-01-01

    Proposes that code switching (CS) and code mixing are natural phenomena that may result in increased competency in various communicative contexts. Both assets and deficits of CS are analyzed, and an ethnographic approach to the variable underlying CS is recommended. (32 references) (Author/VWL)

  11. Study of heat transfer phenomenon during natural convection

    NASA Astrophysics Data System (ADS)

    Yousaf, Muhammad

    The purpose of the present study was to numerically investigate the effects of the roughness elements on the heat transfer during natural convection. A computational algorithm was developed based on the Lattice Boltzmann method to conduct numerical study in two-dimensional rectangular cavities and Rayleigh-Benard cell. A single relaxation time Bhatnagar-Gross-Krook model of Lattice Boltzmann method was used to solve the coupled momentum and energy equations in two-dimensional lattices. Computational model was validated against previous benchmark solutions, and a good agreement was found to exist. A Newtonian fluid of Prandtl (Pr) number 1.0 was considered for this numerical study. The range of Ra numbers was investigated from 103 to 106. The roughness was introduced in the form of sinusoidal elements on a hot, cold, and both the hot and cold walls of the cavities and Rayleigh-Benard cell. The frequency or number of the roughness elements and the dimensionless amplitude (h/H) were varied from 2 to 10 and 0.015 to 0.15 respectively. Numerical results showed that thermal and hydrodynamic behaviors of the fluid were considerably affected in the presence of the roughness elements. A dimensionless amplitude of approximately 0.025 has no significant effects on the average heat transfer. In contrast, a dimensionless amplitude of ≥0.05 cause a degradation in the average heat transfer and delay in the onset of natural convection. The maximum reduction in the average heat transfer was calculated to be approximately 51 percent in the Rayleigh-Benard convection when the roughness was present on both the hot and cold walls with a dimensionless amplitude of 0.15 and the number of roughness elements equal to 10.

  12. Structure and predictability of the El Nino/Southern Oscillation phenomenon in a coupled ocean-atmosphere general circulation model

    SciTech Connect

    Latif, M.; Sterl, A.; Maier-Reimer, E.; Junge, M.M. )

    1993-04-01

    The space-time structure and predictability of the El Nino/Southern Oscillation (ENSO) phenomenon was investigated. Two comprehensive datasets were analyzed by means of an advanced statistical method, one based on observational data and other on data derived from an extended-range integration performed with a coupled ocean atmosphere general circulation model. It is shown that a considerable portion of the ENSO related low-frequency climate variability in both datasets is associated with a cycle implies the possibility of climate predictions in the tropics up to lead times of about one year. This is shown by conducting an ensemble of predictions with our coupled general circulation model. For the first time a coupled model of this type was successfully applied to ENSO predictions. 34 refs., 6 figs.

  13. Decay heat removal in HTGRs by Natural Circulation

    SciTech Connect

    Tzoref, J.; Saphier, D.

    1990-01-01

    The coolability of a conceptual 1000-MW(thermal) high-temperature gas-cooled reactor (HTGR) with complete loss of forced circulation is investigated. Similar design concepts have been proposed by several designers. The important question is whether, for the given geometrical configuration and power density, natural circulation can be developed within a sufficiently short period so that passive cooling devices can be used to remove the decay heat. From the present study, it was concluded that if the reactor remains pressurized during the accident, and if passage near a passive cooling device with a minimum 0.3% nominal heat removal capacity of the reactor nominal decay power can be established, then the maximum fuel temperature will always stay below the 1600{degree}C limit, which is the limit for the beginning of fission product release. The generated decay heat under such conditions is partly removed by the developed natural circulation to the passive heat sink, whereas the rest is absorbed by the system large heat capacity. At the beginning of the accident, most of the decay heat is absorbed by the graphite in the thermal shield structure metal. In the course of the accident, the relative part of the heat dominant. The study was performed by using the DSNP modular simulation language. A dynamic model was developed for the natural circulation flow in the primary loop of a medium-size HTGR during loss of forced circulation.

  14. Performance of Liquid Metals in Natural Circulation Cooled Nuclear Reactors

    SciTech Connect

    Ceballos, Carlos; Lathouwers, Danny; Verkooijen, Adrian

    2004-07-01

    The inherent safety capability of natural circulation makes reactor design more reliable. Additionally, the construction and operation of a nuclear power plant with natural circulation in the primary cooling circuit is an interesting alternative for nuclear plant designers, due to their lower operational and investment costs obtained by simplifying systems and controls. This paper deals with the feasibility of application of natural circulation in the primary cooling circuit of a liquid metal fast reactor. The methodology employed is a non-dimensional analysis, which describes the relationship between the physical properties and system variables. The performance criterion is bounded by a safety argument, referring to the maximum cladding temperature allowed during operation. The study considers several coolants, which can play a part in reactor cooling systems, such as lead, lead-bismuth and sodium. Bismuth and gallium are included in this analysis, in order to extend the range of properties for reference purposes. The results present a characterization of natural circulation flow in a reactor and compare the cooling capabilities from different liquid metals coolants. (authors)

  15. Validation of SSC using the FFTF natural-circulation tests

    SciTech Connect

    Horak, W.C.; Guppy, J.G.; Kennett, R.J.

    1982-01-01

    As part of the Super System Code (SSC) validation program, the 100% power FFTF natural circulation test has been simulated using SSC. A detailed 19 channel, 2 loop model was used in SSC. Comparisons showed SSC calculations to be in good agreement with the Fast Flux Test Facility (FFTF), test data. Simulation of the test was obtained in real time.

  16. FFTF operating experience with sodium natural circulation: slides included

    SciTech Connect

    Burke, T.M.; Additon, S.L.; Beaver, T.R.; Midgett, J.C.

    1981-01-01

    The Fast Flux Test Facility (FFTF) has been designed for passive, back-up, safety grade decay heat removal utilizing natural circulation of the sodium coolant. This paper discusses the process by which operator preparation for this emergency operating mode has been assured, in paralled with the design verification during the FFTF startup and acceptance testing program. Over the course of the test program, additional insights were gained through the testing program, through on-going plant analyses and through general safety evaluations performed throughout the nuclear industry. These insights led to development of improved operator training material for control of decay heat removal during both forced and natural circulation as well as improvements in the related plant operating procedures.

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

    SciTech Connect

    Yoder Jr, Graydon L; Heatherly, Dennis Wayne; Williams, David F; Elkassabgi, Yousri M.; Caja, Joseph; Caja, Mario; Jordan, John; Salinas, Roberto

    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.

  18. Control of natural circulation loops by electrohydrodynamic pumping

    NASA Astrophysics Data System (ADS)

    Grassi, W.; Testi, D.; Della Vista, D.

    2014-04-01

    The paper analyses the effect of electrohydrodynamic (EHD) pumping on the control of natural circulation loops (NCLs). The two major objectives of the investigation are: finding the optimal configuration of an EHD pump and demonstrating that the NCL flow direction can be inverted by exploiting the EHD phenomena. In the initial experimental set-up, we measured the static pressure rise given by an EHD pump made of three consecutive modules of point-ring electrodes for different dielectric fluids and electrode materials. When reversing the polarity of the applied DC voltage, we observed opposite pumping directions, suggesting the presence of two distinct EHD phenomena, inducing motion on opposite directions: ion-drag pumping and conduction pumping. The former was identified as a more efficient process compared to the latter. Based on these preliminary experiments, we built a NCL, operating with the fluid HFE-7100. Two oppositely mounted optimised pumping sections could be alternately activated, to promote clockwise or anticlockwise motion. In the first series of tests, alternately, the pumping sections were triggered prior to the heat input. In any case, the circulation followed the EHD pumping direction. In other tests, the electric field was applied when natural circulation was already present and the flow was reversed by means of opposite EHD pumping, at both polarities. Simply inverting the polarity of the applied voltage, we could alternate ion-drag and conduction pumping; in this way, we easily controlled the direction of motion by means of a single EHD pumping device.

  19. Naturally forced multidecadal variability of the Atlantic meridional overturning circulation

    NASA Astrophysics Data System (ADS)

    Menary, Matthew; Scaife, Adam

    2014-05-01

    The mechanisms by which natural forcing factors alone could drive simulated multidecadal variability in the Atlantic Meridional Overturning Circulation (AMOC) are assessed in an ensemble of climate model simulations. It is shown for a new state-of-the-art general circulation model, HadGEM2-ES, that the most important of these natural forcings, in terms of the multidecadal response of the AMOC, is solar rather than volcanic forcing. AMOC strengthening occurs through a densification of the North Atlantic, driven by anomalous surface freshwater fluxes due to increased evaporation. These are related to persistent North Atlantic atmospheric circulation anomalies, driven by forced changes in the stratosphere, associated with anomalously weak solar irradiance during the late nineteenth and early twentieth centuries. Within a period of approximately 100 years the 11-year smoothed ensemble mean AMOC strengthens by 1.5Sv and subsequently weakens by 1.9Sv, representing respectively approximately 3 and 4 standard deviations of the 11-year smoothed control simulation. The solar-induced variability of the AMOC has various relevant climate impacts, such as a northward shift of the intertropical convergence zone, anomalous Amazonian rainfall, and a sustained increase in European temperatures. While this model has only a partial representation of the atmospheric response to solar variability, these results demonstrate the potential for solar variability to have a multidecadal impact on North Atlantic climate.

  20. Pattern of Circulation of Norovirus GII Strains during Natural Infection

    PubMed Central

    Fobisong, Cajetan; Tah, Ferdinand; Lindh, Magnus; Nkuo-Akenji, Theresia; Bergström, Tomas

    2014-01-01

    Norovirus (NoV) is considered a major cause of nonbacterial gastroenteritis among people of all ages worldwide, but the natural course of infection is incompletely known. In this study, the pattern of circulation of NoVs was studied among 146 children and 137 adults in a small community in southwestern Cameroon. The participants provided monthly fecal samples during a year. NoV RNA was detected in at least one sample from 82 (29%) of the participants. The partial VP1 region could be sequenced in 36 NoV GII-positive samples. Three different genotypes were identified (GII.1, GII.4, and GII.17), with each genotype circulating within 2 to 3 months and reappearing after a relapse period of 2 to 3 months. Most infections occurred once, and 2 episodes at most within a year were detected. No difference in the frequency of NoV infection between children and adults was recorded. The same genotype was detected for a maximum of 2 consecutive months in 3 children only, suggesting that a less than 30-day duration of viral shedding in natural infection was common. Reinfection within a year with the same genotype was not observed, consistent with short-term homotypic immune protection. The study revealed that NoV strains are circulating with a limited duration of viral shedding both in the individuals and the population as part of their natural infection. The results also provide evidence of cross-protective immunity of limited duration between genotypes of the same genogroup. PMID:25274996

  1. Pattern of circulation of norovirus GII strains during natural infection.

    PubMed

    Ayukekbong, James Ayukepi; Fobisong, Cajetan; Tah, Ferdinand; Lindh, Magnus; Nkuo-Akenji, Theresia; Bergström, Tomas

    2014-12-01

    Norovirus (NoV) is considered a major cause of nonbacterial gastroenteritis among people of all ages worldwide, but the natural course of infection is incompletely known. In this study, the pattern of circulation of NoVs was studied among 146 children and 137 adults in a small community in southwestern Cameroon. The participants provided monthly fecal samples during a year. NoV RNA was detected in at least one sample from 82 (29%) of the participants. The partial VP1 region could be sequenced in 36 NoV GII-positive samples. Three different genotypes were identified (GII.1, GII.4, and GII.17), with each genotype circulating within 2 to 3 months and reappearing after a relapse period of 2 to 3 months. Most infections occurred once, and 2 episodes at most within a year were detected. No difference in the frequency of NoV infection between children and adults was recorded. The same genotype was detected for a maximum of 2 consecutive months in 3 children only, suggesting that a less than 30-day duration of viral shedding in natural infection was common. Reinfection within a year with the same genotype was not observed, consistent with short-term homotypic immune protection. The study revealed that NoV strains are circulating with a limited duration of viral shedding both in the individuals and the population as part of their natural infection. The results also provide evidence of cross-protective immunity of limited duration between genotypes of the same genogroup. Copyright © 2014, American Society for Microbiology. All Rights Reserved.

  2. Experimental Observations of Natural Circulation Flow in the NSTF

    SciTech Connect

    Lisowski, Darius; Kraus, Adam R.; Bucknor, Matthew D.; Hu, Rui; Farmer, Mitchell T.

    2016-09-01

    A 1/2 scale test facility has been constructed at Argonne National Laboratory to study the heat removal performance and natural circulation flow patterns in a Reactor Cavity Cooling System (RCCS). Our test facility, the Natural convection Shutdown heat removal Test Facility (NSTF), supports the broader goal of developing an inherently safe and fully passive ex-vessel decay heat removal for advanced reactor designs. The project, initiated in 2010 to support the Advanced Reactor Technologies (ART), Small Modular Reactor (SMR), and Next Generation Nuclear Plant (NGNP) programs, has been conducting experimental operations since early 2014. The following paper provides a summary of some primary design features of the 26-m tall test facility along with a description of the data acquisition suite that guides our experimental practices. Specifics of the distributed fiber optic temperature measurements will be discussed, which introduces an unparalleled level of data density that has never before been implemented in a large scale natural circulation test facility. Results from our test series will then be presented, which provide insight into the thermal hydraulic behavior at steady-state and transient conditions for varying heat flux levels and exhaust chimney configuration states. (C) 2016 Elsevier B.V. All rights reserved.

  3. Numerical simulation of losses along a natural circulation helium loop

    SciTech Connect

    Knížat, Branislav Urban, František Mlkvik, Marek Ridzoň, František Olšiak, Róbert

    2016-06-30

    A natural circulation helium loop appears to be a perspective passive method of a nuclear reactor cooling. When designing this device, it is important to analyze the mechanism of an internal flow. The flow of helium in the loop is set in motion due to a difference of hydrostatic pressures between cold and hot branch. Steady flow at a requested flow rate occurs when the buoyancy force is adjusted to resistances against the flow. Considering the fact that the buoyancy force is proportional to a difference of temperatures in both branches, it is important to estimate the losses correctly in the process of design. The paper deals with the calculation of losses in branches of the natural circulation helium loop by methods of CFD. The results of calculations are an important basis for the hydraulic design of both exchangers (heater and cooler). The analysis was carried out for the existing model of a helium loop of the height 10 m and nominal heat power 250 kW.

  4. Modeling of a coal-fired natural circulation boiler

    SciTech Connect

    Bhambare, K.S.; Mitra, S.K.; Gaitonde, U.N.

    2007-06-15

    Modeling of a natural circulation boiler for a coal-fired thermal power station is presented here. The boiler system is divided into seven subcomponents, and for each section, models based on conservation of mass, momentum, and energy are formulated. The pressure drop at various sections and the heat transfer coefficients are computed using empirical correlations. Solutions are obtained by using SIMULINK. The model is validated by comparing its steady state and dynamic responses with the actual plant data. Open loop responses of the model to the step changes in the operating parameters, such as pressure, temperature, steam flow, feed water flow, are also analyzed. The present model can be used for the development and design of effective boiler control systems.

  5. Numerical study on the Welander oscillatory natural circulation problem using high-order numerical methods

    DOE PAGES

    Zou, Ling; Zhao, Haihua; Kim, Seung Jun

    2016-11-16

    In this study, the classical Welander’s oscillatory natural circulation problem is investigated using high-order numerical methods. As originally studied by Welander, the fluid motion in a differentially heated fluid loop can exhibit stable, weakly instable, and strongly instable modes. A theoretical stability map has also been originally derived from the stability analysis. Numerical results obtained in this paper show very good agreement with Welander’s theoretical derivations. For stable cases, numerical results from both the high-order and low-order numerical methods agree well with the non-dimensional flow rate analytically derived. The high-order numerical methods give much less numerical errors compared to themore » low-order methods. For stability analysis, the high-order numerical methods could perfectly predict the stability map, while the low-order numerical methods failed to do so. For all theoretically unstable cases, the low-order methods predicted them to be stable. The result obtained in this paper is a strong evidence to show the benefits of using high-order numerical methods over the low-order ones, when they are applied to simulate natural circulation phenomenon that has already gain increasing interests in many future nuclear reactor designs.« less

  6. Numerical study on the Welander oscillatory natural circulation problem using high-order numerical methods

    SciTech Connect

    Zou, Ling; Zhao, Haihua; Kim, Seung Jun

    2016-11-16

    In this study, the classical Welander’s oscillatory natural circulation problem is investigated using high-order numerical methods. As originally studied by Welander, the fluid motion in a differentially heated fluid loop can exhibit stable, weakly instable, and strongly instable modes. A theoretical stability map has also been originally derived from the stability analysis. Numerical results obtained in this paper show very good agreement with Welander’s theoretical derivations. For stable cases, numerical results from both the high-order and low-order numerical methods agree well with the non-dimensional flow rate analytically derived. The high-order numerical methods give much less numerical errors compared to the low-order methods. For stability analysis, the high-order numerical methods could perfectly predict the stability map, while the low-order numerical methods failed to do so. For all theoretically unstable cases, the low-order methods predicted them to be stable. The result obtained in this paper is a strong evidence to show the benefits of using high-order numerical methods over the low-order ones, when they are applied to simulate natural circulation phenomenon that has already gain increasing interests in many future nuclear reactor designs.

  7. Transient boiling in two-phase helium natural circulation loops

    NASA Astrophysics Data System (ADS)

    Furci, H.; Baudouy, B.; Four, A.; Meuris, C.

    2014-01-01

    Two-phase helium natural circulation loops are used for cooling large superconducting magnets, as CMS for LHC. During normal operation or in the case of incidents, transients are exerted on the cooling system. Here a cooling system of this type is studied experimentally. Sudden power changes are operated on a vertical-heated-section natural convection loop, simulating a fast increase of heat deposition on magnet cooling pipes. Mass flow rate, heated section wall temperature and pressure drop variations are measured as a function of time, to assess the time behavior concerning the boiling regime according to the values of power injected on the heated section. The boiling curves and critical heat flux (CHF) values have been obtained in steady state. Temperature evolution has been observed in order to explore the operating ranges where heat transfer is deteriorated. Premature film boiling has been observed during transients on the heated section in some power ranges, even at appreciably lower values than the CHF. A way of attenuating these undesired temperature excursions has been identified through the application of high enough initial heating power.

  8. Dengue serotype circulation in natural populations of Aedes aegypti.

    PubMed

    Dos Santos, Taissa Pereira; Cruz, Oswaldo Gonsalvez; da Silva, Keli Antunes Barbosa; de Castro, Márcia Gonçalves; de Brito, Anielly Ferreira; Maspero, Renato Cesar; de Alcântra, Rosilene; Dos Santos, Flávia Barreto; Honorio, Nildimar A; Lourenço-de-Oliveira, Ricardo

    2017-07-23

    Ae. aegypti is the main vector of dengue (DENV), Zika (ZIKV), and chikungunya (CHIKV) viruses. The transmission dynamics of these arboviruses, especially the arboviral circulation in the mosquito population during low and high transmission seasons in endemic areas are still poorly understood. We conducted an entomological survey to determine dengue infection rates in Ae. aegypti and Aedes albopictus. These collections were performed in 2012-2013 during a Rio de Janeiro epidemic, just before the introduction and spread of ZIKV and CHIKV in the city. MosquiTrap(©) and BG-Sentinel traps were installed in three fixed and seven itinerant neighborhoods each month over ten months. Mosquitoes were in supernatants pools tested and individually confirmed for DENV infection using RT-PCR. A total of 3053 Aedes mosquitos were captured and Ae. aegypti was much more frequent (92.9%) than Ae. albopictus (6.8%). Ae. aegypti females accounted for 71.8% of captured mosquitoes by MosquitTrap(©) and were the only species found naturally infected with DENV (infection rate=0.81%). Only one Ae. aegypti male, collected by BG-sentinel, was also tested positive for DENV. The peak of DENV-positive mosquitoes coincided the season of the highest incidence of human cases. The most common serotypes detected in mosquitoes were DENV-3 (24%) and DENV-1 (24%), followed by DENV-4 (20%), DENV-2 (8%) and DENV-1 plus DENV4 (4%), while 95% of laboratory-confirmed human infections in the period were due to DENV-4. These contrasting results suggest silent maintenance of DENV serotypes during the epidemics, reinforcing the importance of entomological and viral surveillance in endemic areas. Copyright © 2017 Elsevier B.V. All rights reserved.

  9. On the stability of natural circulation loops with phase change

    NASA Astrophysics Data System (ADS)

    Haskin, Troy C.

    The stability of a simple, closed-loop, water-cooled natural circulation system was characterized over a range of single phase and two-phase states. The motivation for this investigation is a Next Generation Nuclear Plant safety cooling system called the Reactor Cavity Cooling System (RCCS). One of the proposed designs for the RCCS is a closed-circuit of network piping using water as a working fluid. One of the safety considerations for such a system is the stability of the system at steady-state under a large number of unknown states. This work provides a derivation of the commonly used one-dimensional conservation laws used in thermohydraulic system modeling and a novel discretization scheme that allows for exact integration of the computational domain for accurate calculation of eigenvalues of a linearized system. The steady-state solution of the discretized equations is then performed using a fully nonlinear Jacobian-Free Newton Krylov Method for a number of temperatures, pressures, and heat loads both in single and two-phase conditions. All of the single and two-phase state exhibit linear stability to small perturbations in values. The linear stability is also found to increase with increasing heat load due to the greater inertia of the system damping out small perturbation effectively and with increasing pressure due to the greater stiffness of the fluid. Nonlinear stability was also examined for a point power insertion of varying intensity from two steady-states. The loop exhibited stability for all power insertions from both steady-states, returning to the initial steady value shortly after the pulse.

  10. Investigations on the thermal-hydraulics of a natural circulation cooled BWR fuel assembly

    SciTech Connect

    Kok, H.V.; Hagen, T.H.J.J. van der; Mudde, R.F.

    1995-09-01

    A scaled natural circulation loop facility has been built after the Dodewaard Boiling Water Reactor, which is the only operating natural circulation cooled BWR in the world. The loop comprises one fuel assembly, a riser with a downcomer and a condenser with a cooling system. Freon-12 is used as a scaling liquid. This paper reports on the first measurements done with this facility. Quantities like the circulation flow, carry-under and the void-fraction have been measured as a function of power, pressure, liquid level, riser length, condensate temperature and friction factors. The behavior of the circulation flow can be understood by considering the driving force. Special attention has been paid to the carry-under, which has been shown to have a very important impact on the dynamics of a natural circulation cooled BWR.

  11. Phenomenon of organic carbon change in natural waters (system "catchment - Lake") of Russian Federation

    NASA Astrophysics Data System (ADS)

    Dinu, Marina; Tatyana, Moiseenko; Tatyana, Kremleva; Natalia, Gashkina

    2015-04-01

    this phenomenon. The water color is predominantly determined by large molecules of humus acids which molecular weight >1000 Da. Macromolecular organic substances of humus type can be dissociated in water with formation of a free proton, as well as enter into reactions of decomposition (hydrolysis) and disproportionation with formation of low-molecular weight fragments. Its fragments also are dissociated of proton (see the diagram below). Non-organic strong acids supplied from anthropogenic and natural sources may catalyze the above processes. The diagram of the organic substances destruction of humus origin is given below, where Ri means non-symmetrical fragments of a natural polymer, X_iH - functional groups of organic substances of humus origin, and n - number of protons. begin{equation*} HX_1-R_1-R_2-X_2H begin{array}{l} → R_1-X_1H + R_2-X_2H quad + quad R{^'}{_1} X1^- + R{^'}{_2} X2^- + nH+ → HX_1-R_1-R2 X_2- + - X_1R_1-R_2-X_2H + - X_1R_1-R2 X_2- + nH+ end{equation*} When strong acids get into a water environment humus acids are degraded into fractions. It could be supposed that the organic matter structure undergoes changes in natural waters, as the fraction of high-molecular weight humus acids decrease. As a consequence of interaction between humus substances and protons the humic acids precipitate to form bottom sediments, whereas fulvic acids remain in water. Fulvic acids are characterized by lower molecular weights (from 500 to 2000 Da) and exert an insignificant effect on the water color. Skelkvale, B.L., J.L. Stoddard, D.S. Jeffries, K. Torseth, T. Hogasen, J. Bowman, L. Mannio, Monteith, D.T., et al. 2005. Regional scale evidence for improvements in surface water chemistry 1990-2001. Environmental Pollution 137(1): 165-176. Moiseenko, T., L. Kudrjavzeva, I. Rodyshkin. 2001. The episodic acidification of small streams in the spring flood period of industrial polar region, Russia. Chemosphere 362: 45-50.

  12. Children's Independent Exploration of a Natural Phenomenon by Using a Pictorial Computer-Based Simulation.

    ERIC Educational Resources Information Center

    Kangassalo, Marjatta.

    1994-01-01

    Examines children's understanding of the variation of sunlight and heat of the sun as experienced on the earth related to the positions of the earth and the sun in space, while using a pictorial computer simulation of the phenomenon. Suggests that, through the exploration of the program, children seemed to follow a correctly directed conceptual…

  13. Dense intermediate water outflow from the Cretan Sea: A salinity driven, recurrent phenomenon, connected to thermohaline circulation changes

    NASA Astrophysics Data System (ADS)

    Velaoras, Dimitris; Krokos, George; Nittis, Kostas; Theocharis, Alexander

    2014-08-01

    Data collected from different platforms in the Cretan Sea during the 2000s decade present evidence of gradually increasing salinity in the intermediate and deep intermediate layers after the middle of the decade. The observed gradual salt transport toward the deeper layers indicates contributions of dense water masses formed in various Aegean Sea subbasins. The accumulation of these saline and dense water masses in the Cretan Sea finally led to outflow from both Cretan Straits, with density greater than typical Levantine/Cretan Intermediate water but not dense enough to penetrate into the deep layers of the Eastern Mediterranean. We name this outflowing water mass as dense Cretan Intermediate Water (dCIW). A retrospective analysis of in situ data and literature references during the last four decades shows that similar events have occurred in the past in two occasions: (a) in the 1970s and (b) during the Eastern Mediterranean Transient (EMT) onset (1987-1991). We argue that these salinity-driven Aegean outflows are mostly attributed to recurrent changes of the Eastern Mediterranean upper thermohaline circulation that create favorable dense water formation conditions in the Aegean Sea through salinity preconditioning. We identify these phenomena as "EMT-like" events and argue that in these cases internal thermohaline mechanisms dominate over atmospheric forcing in dense water production. However, intense atmospheric forcing over an already salinity preconditioned basin is indispensable for creating massive deep water outflow from the Cretan Sea, such as the EMT event.

  14. Thermal Disparity between Fingers after Cold-water Immersion of Hands: A Useful Indicator of Disturbed Peripheral Circulation in Raynaud Phenomenon Patients.

    PubMed

    Horikoshi, Masanobu; Inokuma, Shigeko; Kijima, Yasuo; Kobuna, Mika; Miura, Yoko; Okada, Rika; Kobayashi, Shoko

    2016-01-01

    To devise an effective method to assess the peripheral circulation using an infrared thermographic analysis. Sequential measurements of the skin temperature before and after cold-water immersion of the hands were analyzed by a thermographic examination in healthy controls and patients diagnosed to have Raynaud phenomenon (RP). The skin temperatures of the dorsum of all fingernail folds and the metacarpophalangeal (MCP) joints were measured at baseline. Then the hands were immersed in 10°C water for 10 s, and the skin temperatures were measured at 0, 3, 5, 10, 15, 20 and 30 min after immersion. The mean temperature, recovery rate and disparity (coefficient of variation) of the nail fold temperatures were calculated. The distal-dorsal difference (DDD) was calculated by subtracting the mean MCP temperature from the mean nail fold temperature. Receiver operating characteristic (ROC) curves were generated to compare these parameters in terms of their capability to differentiate patients with RP. Thirty-one RP patients and 25 controls were included in the study. The baseline nail fold temperature was significantly lower in RP patients than in the controls. The RP patients had a lower recovery rate, lower DDD and higher disparity than the controls. The disparity and DDD were negatively correlated (r=-0.63, p<0.01), whereas the recovery rate and DDD were positively correlated (r=0.91, p<0.01). The ROC curve analysis revealed that the disparity in nail fold temperature effectively differentiated RP patients from controls (area under the curve: recovery rate 0.72; disparity 0.88; DDD 0.79). The temperature disparity between fingers is a useful thermographic parameter for evaluating disturbed peripheral circulation in patients with Raynaud phenomenon.

  15. Salt marsh productivity with natural and altered tidal circulation.

    PubMed

    Zedler, Joy B; Winfield, Ted; Williams, Phil

    1980-01-01

    The effects of altered tidal circulation on southern California salt marshes are investigated by comparing a well-flushed wetland and two modified wetlands which have reduced tidal flow. The Tijuana Estuary had continuous exchange of seawater but relatively low net aerial primary productivity (0.4-1.0 kg m(-2)yr(-1)) of vascular plants. Low productivity (0.6 kg m(-2)yr(-1)) was also found in the Flood Control Channel of the San Diego River, where tidal exchange was restricted to flow through a riprap dike. High productivity (1.2-2.9 kg m(-2)yr(-1)) in Los Penasquitos Lagoon was attributed to the influences of freshwater impounded behind a sand bar which blocked the mouth of the lagoon during much of the study period.It is hypothesized that elimination of tidal flow during the growing season increased primary productivity of vascular plants because freshwater runoff decreased soil salinity and because nutrients were retained within the marsh. However, we predict that sand bar obstruction can decrease productivity if below-average rainfall leads to hypersalinity of closed lagoons. Comprehensive evaluation of the effects of altered tidal circulation requires longterm study and examination of the total ecosystem.

  16. The nature of the sunspot phenomenon. I - Solutions of the heat transport equation

    NASA Technical Reports Server (NTRS)

    Parker, E. N.

    1974-01-01

    It is pointed out that sunspots represent a disruption in the uniform flow of heat through the convective zone. The basic sunspot structure is, therefore, determined by the energy transport equation. The solutions of this equation for the case of stochastic heat transport are examined. It is concluded that a sunspot is basically a region of enhanced, rather than inhibited, energy transport and emissivity. The heat flow equations are discussed and attention is given to the shallow depth of the sunspot phenomenon. The sunspot is seen as a heat engine of high efficiency which converts most of the heat flux into hydromagnetic waves.

  17. Natural circulating passive cooling system for nuclear reactor containment structure

    DOEpatents

    Gou, Perng-Fei; Wade, Gentry E.

    1990-01-01

    A passive cooling system for the contaminant structure of a nuclear reactor plant providing protection against overpressure within the containment attributable to inadvertent leakage or rupture of the system components. The cooling system utilizes natural convection for transferring heat imbalances and enables the discharge of irradiation free thermal energy to the atmosphere for heat disposal from the system.

  18. Bridging Troubled Waters: Historians, Natural Resource Litigation, and the Expert Witness Phenomenon.

    PubMed

    Brescia, Michael M

    2015-02-01

    This special issue of The Public Historian examines the nature and scope of the historian's role as a consultant and expert witness in natural resource litigation. The introductory essay identifies the major issues and challenges that historians face when they bring their knowledge, skills, and professional best standards into law offices and courtrooms, while also positing a conceptual framework for public history practitioners to better understand and appreciate the larger stakes in conducting research for environmental litigation. The author delineates his own experience as an expert in certain water rights cases in the American Southwest where knowledge of the Spanish and Mexican civil law of property is essential.

  19. The simulation of start-up of natural circulation boiler based on the Astrom-Bell model

    NASA Astrophysics Data System (ADS)

    Zhang, Tianyu; Zhao, Zhenning; Li, Yuanyuan; Zhu, Xianran

    2017-01-01

    This paper presents a numerical investigation on the dynamic analysis of steam and water system of the natural circulation boiler SHL35.2.5/AI with the software MATLAB/SIMULINK. Based on the four-order Astrom-Bell model, a model applicable the specific boiler was established, casting light on the changes in parameters of designed, cold start and varying load condition. And a curve of cold start is obtained, which can be taken as reference for practical operation. In addition, in the condition of varying load, our model captured the phenomenon of false water level, and according analysis is made. Our study introduces a feasible method of simulation on the dynamic analysis of steam and water system on other boilers as well.

  20. Physical nature of longevity of light actinides in dynamic failure phenomenon

    SciTech Connect

    Uchaev, A. Ya. Punin, V. T.; Selchenkova, N. I.; Kosheleva, E. V.; Kosachev, V. V.

    2015-12-15

    It is shown in this work that the physical nature of the longevity of light actinides under extreme conditions in a range of nonequilibrium states of t ∼ 10{sup –6}–10{sup –10} s is determined by the time needed for the formation of a critical concentration of a cascade of failure centers, which changes connectivity of the body. These centers form a percolation cluster. The longevity is composed of waiting time t{sub w} for the appearance of failure centers and clusterization time t{sub c} of cascade of failure centers, when connectivity in the system of failure centers and the percolation cluster arise. A unique mechanism of the dynamic failure process, a unique order parameter, and an equal dimensionality of the space in which the process occurs determine the physical nature of the longevity of metals, including fissionable materials.

  1. System Analysis for Decay Heat Removal in Lead-Bismuth Cooled Natural Circulated Reactors

    SciTech Connect

    Takaaki Sakai; Yasuhiro Enuma; Takashi Iwasaki; Kazuhiro Ohyama

    2002-07-01

    Decay heat removal analyses for lead-bismuth cooled natural circulation reactors are described in this paper. A combined multi-dimensional plant dynamics code (MSG-COPD) has been developed to conduct the system analysis for the natural circulation reactors. For the preliminary study, transient analysis has been performed for a 100 MWe lead-bismuth-cooled reactor designed by Argonne National Laboratory (ANL). In addition, decay heat removal characteristics of a 400 MWe lead-bismuth-cooled natural circulation reactor designed by Japan Nuclear Cycle Development Institute (JNC) has been evaluated by using MSG-COPD. PRACS (Primary Reactor Auxiliary Cooling System) is prepared for the JNC's concept to get sufficient heat removal capacity. During 2000 sec after the transient, the outlet temperature shows increasing tendency up to the maximum temperature of 430 Centigrade, because the buoyancy force in a primary circulation path is temporary reduced. However, the natural circulation is recovered by the PRACS system and the out let temperature decreases successfully. (authors)

  2. System Analysis for Decay Heat Removal in Lead-Bismuth-Cooled Natural-Circulation Reactors

    SciTech Connect

    Sakai, Takaaki; Enuma, Yasuhiro; Iwasaki, Takashi

    2004-03-15

    Decay heat removal analyses for lead-bismuth-cooled natural-circulation reactors are described in this paper. A combined multidimensional plant dynamics code (MSG-COPD) has been developed to conduct the system analysis for the natural-circulation reactors. For the preliminary study, transient analysis has been performed for a 300-MW(thermal) lead-bismuth-cooled reactor designed by Argonne National Laboratory. In addition, decay heat removal characteristics of a 400-MW(electric) lead-bismuth-cooled natural-circulation reactor designed by the Japan Nuclear Cycle Development Institute (JNC) has been evaluated by using MSG-COPD. The primary reactor auxiliary cooling system (PRACS) is prepared for the JNC concept to get sufficient heat removal capacity. During 2000 s after the transient, the outlet temperature shows increasing tendency up to the maximum temperature of 430 deg. C because the buoyancy force in a primary circulation path is temporarily reduced. However, the natural circulation is recovered by the PRACS system, and the outlet temperature decreases successfully.

  3. Density wave oscillations of a boiling natural circulation loop induced by flashing

    SciTech Connect

    Furuya, Masahiro; Inada, Fumio; Yasuo, Akira

    1995-09-01

    Experiments are conducted to investigate two-phase flow instabilities in a boiling natural circulation loop with a chimney due to flashing in the chimney at lower pressure. The test facility used in this experiment is designed to have non-dimensional values which are nearly equal to those of natural circulation BWR. Stability maps in reference to the heat flux, the inlet subcooling, the system pressure are presented. This instability is suggested to be density wave oscillations due to flashing in the chimney, and the differences from other phenomena such as flow pattern oscillations and geysering phenomena are discussed by investigating the dynamic characteristics, the oscillation period, and the transient flow pattern.

  4. On Stability of Natural-circulation-cooled Boiling Water Reactors during Start-up (Experimental Results)

    SciTech Connect

    Manera, A.; Van der Hagen, T.H.J.J.

    2002-07-01

    The characteristics of flashing-induced instabilities, which are of importance during the start-up phase of natural-circulation Boiling Water Reactors (BWRs), are studied. Experiments at typical start-up conditions (low power and low pressure) are carried out on a steam/water natural circulation loop. The mechanism of flashing-induced instability is analyzed in detail and it is found that non-equilibrium between phases and enthalpy transport plays an important role in the instability process. Pressure and steam volume in the steam dome are found to have a stabilizing effect. The main characteristics of the instabilities have been analyzed. (authors)

  5. COBRA-WC model and predictions for a fast-reactor natural-circulation transient. [LMFBR

    SciTech Connect

    George, T.L.; Basehore, K.L.; Prather, W.A.

    1980-01-01

    The COBRA-WC (Whole Core) code has been used to predict the core-wide coolant and rod temperature distribution in a liquid metal fast reactor during the early part (first 220 seconds) of a natural circulation transient. Approximately one-sixth of the core was modeled including bypass flows and the pressure losses above and below the core region. Detailed temperature and flow distributions were obtained for the two test fuel assemblies. The COBRA-WC model, the approach, and predictions of core-wide transient coolant and rod temperatures during a natural circulation transient are presented in this paper.

  6. Characterization of Circulating Natural Killer Cells in Neotropical Primates

    PubMed Central

    Carville, Angela; Evans, Tristan I.; Reeves, R. Keith

    2013-01-01

    Despite extensive use of nonhuman primates as models for infectious diseases and reproductive biology, imprecise phenotypic and functional definitions exist for natural killer (NK) cells. This deficit is particularly significant in the burgeoning use of small, less expensive New World primate species. Using polychromatic flow cytometry, we identified peripheral blood NK cells as CD3-negative and expressing a cluster of cell surface molecules characteristic of NK cells (i.e., NKG2A, NKp46, NKp30) in three New World primate species – common marmosets, cotton-top tamarins, and squirrel monkeys. We then assessed subset distribution using the classical NK markers, CD56 and CD16. In all species, similar to Old World primates, only a minor subset of NK cells was CD56+, and the dominant subset was CD56–CD16+. Interestingly, CD56+ NK cells were primarily cytokine-secreting cells, whereas CD56–CD16+ NK cells expressed significantly greater levels of intracellular perforin, suggesting these cells might have greater potential for cytotoxicity. New World primate species, like Old World primates, also had a minor CD56–CD16– NK cell subset that has no obvious counterpart in humans. Herein we present phenotypic profiles of New World primate NK cell subpopulations that are generally analogous to those found in humans. This conservation among species should support the further use of these species for biomedical research. PMID:24244365

  7. Natural Circulation Patterns in the VHTR Air-Ingress Accident and Related Issues

    SciTech Connect

    Chang Ho Oh; Eung Soo Kim; Hyung Seok Kang

    2010-10-01

    A natural circulation pattern in a Very High Gas-Cooled Reactor during a hypothetical air-ingress accident has been investigated using computational fluid dynamic (CFD) methods in order to compare with the previous 1-D flow path model for the air-ingress analyses. The GT-MHR 600 MWt reactor was selected to be the reference design and modeled by a half symmetric 3-D geometry using FLUENT 6.3, a commercial CFD code. The simulation was carried out as steady-state calculations, and the boundary conditions were either assumed or provided from the 1-D GAMMA code results. Totally, 12 different cases have been estimated, and many notable findings and results have been obtained in this study. According to the simulations, the natural circulation pattern in the reactor was quite different from the previous 1-D assumptions. A large re-circulation flow with thermal stratification phenomena was clearly observed in the hot-leg and the lower plenum in the 3-D model. This re-circulation flow provided approximately an order faster air-ingress speed (0.46 m/s in superficial velocity) than previously predicted values by 1-D modeling (0.02~0.03 m/s). It indicates that the 1-D air-ingress modeling may significantly distort the air-ingress scenario and consequences. In addition, the complicated natural circulation pattern is eventually expected to lead to very complex graphite oxidations and corrosion patterns.

  8. Natural Circulation Patterns in the VHTR Air-Ingress Accident and Related Issues

    SciTech Connect

    Chang H. Oh; Eung S. Kim

    2012-08-01

    Natural circulation patterns in the VHTR during a hypothetical air-ingress accident have been investigated using computational fluid dynamic (CFD) methods in order to compare results from the previous 1-D model which was developed using GAMMA code for the air-ingress analyses. The GT-MHR 600 MWt reactor was selected to be the reference design and modeled by a half symmetric 3-D geometry using FLUENT 6.3, a commercial CFD code. CFD simulations were carried out as the steady-state calculation, and the boundary conditions were either assumed or provided from the 1-D GAMMA code results. Totally, 12 different cases have been reviewed, and many notable results have been obtained through in this work. According to the simulations, natural circulation patterns in the reactor were quite different from the previous 1-D assumptions. A large re-circulation flow with thermal stratification phenomena was clearly observed in the hot-leg and the lower plenum in the 3-D model. This re-circulation flow provided about an order faster air-ingress speed (0.46 m/s in superficial velocity) than previously predicted by 1-D modeling (0.02~0.03 m/s). It indicates that the 1-D air-ingress modeling may significantly distort the air-ingress scenario and consequences. In addition, complicated natural circulation patterns are eventually expected to result in very complex graphite oxidations and corrosion behaviors.

  9. A Signature of Persistent Natural Thermohaline Circulation Cycles in Observed Climate

    NASA Astrophysics Data System (ADS)

    Knight, J.; Allan, R.; Folland, C.; Vellinga, M.; Mann, M.

    2005-12-01

    An ensemble of simulations of 20th Century climate using the HadCM3 coupled climate model forced with estimates of natural and anthropogenic forcings is compared with instrumental temperature data sets. The results show that while external climate forcing can account for most of 20th century climate change, there are also significant multidecadal climate fluctuations that are not produced by forcings. A major part of this variability corresponds to the `Atlantic Multidecadal Oscillation' (AMO), which has been identified in observations, and represents coherent fluctuations in temperature throughout most of the Northern Hemisphere. Using a 1400 year calculation with HadCM3 without external forcings, we show the model produces a quasi-periodic internal mode with a pattern, amplitude and characteristic time scale similar to that of the observed AMO. Further, the model implies the AMO is a genuine long-lived quasi-cyclical climate phenomenon related to large-scale oceanic heat transport variations associated with changes in the strength of the thermohaline circulation (THC) of about 2 Sv (10%). In the simulation, stronger cross-equatorial temperature gradients are associated with the anomalous northward ocean heat transport during a warm AMO phase. This causes a northward displacement of the mean ITCZ, leading to more rainfall and the development of anomalously fresh water in the tropical North Atlantic. These sustained anomalies slowly propagate to the subpolar North Atlantic in about 5 decades, where they act to slow the THC. The results also confirm observed links between the AMO and multidecadal variability in north-east Brazil and Sahel precipitation, and Atlantic hurricane formation. In addition, the simulated link between temperature and the THC allows an estimate of possible past changes in THC strength. Our results imply that the THC has undergone distinct strong and weak phases in the 20th century and has strengthened over recent decades. We also produce a

  10. Multiwavelength Characterization of the Brown Dwarf Auroral Phenomenon - Establishing the Nature of the Electrodynamic Engine

    NASA Astrophysics Data System (ADS)

    Pineda, John Sebastian

    Stellar coronal activity has been shown to persist into the low-mass star regime, down to late M-dwarf spectral types. However, there is now an accumulation of evidence suggesting that at the end of the main sequence there is a transition in the nature of the magnetic activity from chromospheric and coronal to planet-like and auroral, from local impulsive heating via flares and MHD wave dissipation to energy dissipation from strong large-scale magnetospheric current systems. In this dissertation, I examine the effects of these processes on the atmospheres of brown dwarfs across multiple different wavebands and investigate the underlying mechanisms powering the electrodynamic engine responsible for auroral emission in brown dwarfs. I conduct observational surveys looking for the emission features of H-alpha and as indicative of auroral systems across the ultracool dwarf regime. I further provide a comprehensive view of brown dwarf magnetic activity and auroral phenomena, detailing the various emission processes, and expectations for auroral brown dwarfs. I also initiate a preliminary analysis of the detailed emission features and discuss the constraints imposed on the electrodynamic engine of these objects.

  11. Toward Understanding The B[e] Phenomenon. VI. Nature and Spectral Variations of HD 85567.

    NASA Astrophysics Data System (ADS)

    Khokhlov, S. A.; Miroshnichenko, A. S.; Mennickent, R.; Cabezas, M.; Zhanabaev, Z. Zh.; Reichart, D. E.; Ivarsen, K. M.; Haislip, J. B.; Nysewander, M. C.; LaCluyze, A. P.

    2017-01-01

    We report the results of high-resolution (R ∼ 80,000) spectroscopic observations of the emission-line object HD 85567, which has been classified as an FS CMa type object or a pre-main-sequence star. The main goal is to put more constraints on the object’s fundamental parameters, as well as on its nature and evolutionary state. Absorption lines in the spectrum of HD 85567 were found to be similar to those of mid-B-type dwarfs and correspond to the following fundamental parameters: Teff = 15,000 ± 500 K, v\\sin i=31+/- 3 km s‑1, and {log} g∼ 4.0. The interstellar extinction, AV = 0.50 ± 0.02 mag, was measured using the strengths of some diffuse interstellar bands. We also obtained UBV(RI)c images of a 10‧ × 10‧ region around the object. Photometry of projectionally close stars was used to derive an interstellar extinction law in this direction and resulted in a distance of 1300 ± 100 pc to the object and a luminosity of log L/L⊙ = 3.3 ± 0.2. We found no significant radial velocity variations of the absorption lines in the spectra of HD 85567 obtained during two-month-long periods of time in 2012 and 2015. Our analysis of the spectroscopic and photometric data available for the star led us to a conclusion that it cannot be a pre-main-sequence Herbig Ae/Be star. We argue that the circumstellar gas and dust were produced during the object’s evolution as most likely a binary system, which contains an undetected secondary component and is unlikely to be a merger product. This paper is partly based on observations obtained at the 1.5 m telescope of the Cerro Tololo Interamerican Observatory under CNTAC proposal 2012A–016.

  12. Experimental verification of natural convective heat transfer phenomenon from isothermal cuboids

    SciTech Connect

    Radziemska, Ewa; Lewandowski, Witold M.

    2008-02-15

    The paper presents results of experimental investigations of the convective heat transfer from isothermal cuboid with relatively big dimensions (i.e. 1.5 m x 1 m x 0.5 m). The aim of this research was to obtain results, which could be comparable to those obtained for the relatively small cuboid, presented in our previous paper [E. Radziemska, W. Lewandowski, Natural convective heat transfer from isothermal cuboids, Int. J. Heat Mass Transfer 46 (2003) 2169-2178]. The analytical solution was performed, taking into account complete boundary layer length and the manner of its propagation around the isothermal cuboid. As the characteristic linear dimension L in Nusselt-Rayleigh theoretical and experimental correlations, we proposed the ratio of six volumes to the cuboids surface area, which allowed performing the experimental results independently from the orientation of the block. The experiment was then carried out for three possible positions of the tested cuboid with dimensions 0.2 m x 0.1 m x 0.045 m. In present the investigations the Rayleigh numbers based on the proposed characteristic length ranged from 10{sup 8} to 10{sup 9}, due to the cuboids size. The Nusselt number, describing the intensity of convective heat transfer from the cuboid, was expressed by Nu = X . Ra{sup 1/5} +Y . Ra{sup 1/4}, where X and Y are coefficients dependent on the cuboids dimensions. For the range of provided experiment the theoretical Nusselt-Rayleigh relation can be presented in the form: Nu{sub L}=0.452.Ra{sub L}{sup 1/5}+0.516.Ra{sub L}{sup 1/4}that is adequate to Nu{sub L}=0.743.Ra{sub L}{sup 1/4}. A better correlation is obtained for the experimental results: Nu{sub L}=0.90.Ra{sub L}{sup 1/4} has a 10% deviation to the value previously obtained, for the cuboid with small dimensions, results (Nu{sub L}=0.818.Ra{sub L}{sup 1/4}). (author)

  13. Natural circulation analysis for the advanced neutron source reactor refueling process 11

    SciTech Connect

    Tucker, R.F.; Dasardhi, S.; Elkassabgi, Y.; Yoder, G.L.

    1995-09-01

    During the refueling process of the Advanced Neutron Source Reactor (ANSR), the spent fuel elements must be moved from the primary coolant loop (containing D{sub 2}O), through a heavy water pool, and finally into a light water spent fuel storage area. The present refueling scheme utilizes remote refueling equipment to move the spent fuel elements through a D{sub 2}O filled stack and tunnel into a temporary storage canal. A transfer lock is used to move the spent fuel elements from the D{sub 2}O-filled interim storage canal to a light water pool. Each spent fuel element must be cooled during this process, using either natural circulation or forced convection. This paper presents a summary of the numerical techniques used to analyze natural circulation cooling of the ANSR fuel elements as well as selected results of the calculations. Details of the analysis indicate that coolant velocities below 10 cm/s exist in the coolant channels under single phase natural circulation conditions. Also, boiling does not occur within the channels if power levels are below a few hundred kW when the core transitions to natural circulation conditions.

  14. Design and measured performance of a solar chimney for natural circulation solar energy dryers

    SciTech Connect

    Ekechukwu, O.V.; Norton, B.

    1996-02-01

    An experimental solar chimney consisted of a cylindrical polyethylene-clad vertical chamber supported by steel framework and draped internally with a selectively absorbing surface. The performance of the chimney which was monitored extensively is reported. Issues related to the design and construction of solar chimneys for natural circulation solar energy dryers are discussed.

  15. Self-sustained hydrodynamic oscillations in a natural-circulation two-phase-flow boiling loop

    NASA Technical Reports Server (NTRS)

    Jain, K. C.

    1969-01-01

    Results of an experimental and theoretical study of factors affecting self-sustaining hydrodynamic oscillations in boiling-water loops are reported. Data on flow variables, and the effects of geometry, subcooling and pressure on the development of oscillatory behavior in a natural-circulation two-phase-flow boiling loop are included.

  16. What is the nature of the emergence phenomenon when using intravenous or intramuscular ketamine for paediatric procedural sedation?

    PubMed

    Treston, Greg; Bell, Anthony; Cardwell, Rob; Fincher, Gavin; Chand, Dip; Cashion, Geoff

    2009-08-01

    Ketamine has become the drug most favoured by emergency physicians for sedation of children in the ED. Some emergency physicians do not use ketamine for paediatric procedural sedation (PPS) because of concern about emergence delirium on recovery. The present study set out to determine the true incidence and nature of this phenomenon. Prospective data relating to any emergence agitation, crying, hallucinations, dreams, altered perceptions, delirium and necessary interventions were recorded in consecutive cases of ketamine PPS from March 2002 to June 2007, and analysed. Standard inclusion and exclusion criteria for the use of ketamine were followed. A total of 745 prospective data collection records were available for analysis over the 5 year period. Of all, 93 (12.5%) children cried on awakening when recovering from PPS, 291 (39%) experienced pleasant altered perceptions and 16 (2.1%) experienced what was called 'emergence delirium'. None required any active treatment and all except one settled within 20 min. There was no evidence of an increased rate of nightmares on telephone follow up in the weeks post procedure. The belief that ketamine, in the doses used for ED PPS, causes frequent emergence delirium is flawed. A pleasant emergence phenomenon is common, but is not distressing for the child, and has no long-term (up to 30 days) negative sequelae. Rarely, there is anxiety or distress on awakening from ketamine sedation, which settles spontaneously. This should not deter emergency physicians from using ketamine for PPS.

  17. Experimental Investigation of Natural-Circulation Flow Behavior Under Low-Power/Low-Pressure Conditions in the Large-Scale PANDA Facility

    SciTech Connect

    Auban, Olivier; Paladino, Domenico; Zboray, Robert

    2004-12-15

    Twenty-five tests have been carried out in the large-scale thermal-hydraulic facility PANDA to investigate natural-circulation and stability behavior under low-pressure/low-power conditions, when void flashing might play an important role. This work, which extends the current experimental database to a large geometric scale, is of interest notably with regard to the start-up procedures in natural-circulation-cooled boiling water reactors. It should help the understanding of the physical phenomena that may cause flow instability in such conditions and can be used for validation of thermal-hydraulics system codes. The tests were performed at a constant power, balanced by a specific condenser heat removal capacity. The test matrix allowed the reactor pressure vessel power and pressure to be varied, as well as other parameters influencing the natural-circulation flow. The power spectra of flow oscillations showed in a few tests a major and unique resonance peak, and decay ratios between 0.5 and 0.9 have been found. The remainder of the tests showed an even more pronounced stable behavior. A classification of the tests is presented according to the circulation modes (from single-phase to two-phase flow) that could be assumed and particularly to the importance and the localization of the flashing phenomenon.

  18. [El niño phenomenon and natural disasters: public health interventions for disaster preparedness and response].

    PubMed

    Hijar, Gisely; Bonilla, Catherine; Munayco, Cesar V; Gutierrez, Ericson L; Ramos, Willy

    2016-06-01

    This article reviews public health interventions for preparedness and response to natural disasters within the context of El Niño phenomenon using systematic reviews and a review of revisions with emphasis on vector-borne diseases, water-borne diseases, malnutrition, heat stress, drought, flood-associated diseases, mental health problems, vulnerability of the physical health-system infrastructure, as well as long-term policies aimed at protecting the populations of these cases. Environmental interventions were identified, including vector control, chemoprophylaxis, immunization, and intradomiciliary water treatment. While these finds are based primarily on systematic reviews, it is necessary to evaluate the benefit of these interventions within the population, according to the context of each region.

  19. Heat transfer to water from a vertical tube bundle under natural-circulation conditions. [PWR; BWR

    SciTech Connect

    Gruszczynski, M.J.; Viskanta, R.

    1983-01-01

    The natural circulation heat transfer data for longitudinal flow of water outside a vertical rod bundle are needed for developing correlations which can be used in best estimate computer codes to model thermal-hydraulic behavior of nuclear reactor cores under accident or shutdown conditions. The heat transfer coefficient between the fuel rod surface and the coolant is the key parameter required to predict the fuel temperature. Because of the absence of the required heat transfer coefficient data base under natural circulation conditions, experiments have been performed in a natural circulation loop. A seven-tube bundle having a pitch-to-diameter ratio of 1.25 was used as a test heat exchanger. A circulating flow was established in the loop, because of buoyancy differences between its two vertical legs. Steady-state and transient heat transfer measurements have been made over as wide a range of thermal conditions as possible with the system. Steady state heat transfer data were correlated in terms of relevant dimensionless parameters. Empirical correlations for the average Nusselt number, in terms of Reynolds number, Rayleigh number and the ratio of Grashof to Reynolds number are given.

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

    SciTech Connect

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

    2012-11-01

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

  1. Evaluation of natural circulation cooldown tests performed at Diablo Canyon, San Onofre, and Palo Verde nuclear power plants

    SciTech Connect

    Jo, J.H.; Perkins, K.R.; Cavlina, N.

    1988-01-01

    The natural circulation cooldown tests performed at Diablo Canyon, San Onofre, and Palo Verde nuclear power plants were evaluated for the compliance with the US Nuclear Regulatory Commission design requirements. BNL concluded that these tests combined with the supporting analyses demonstrated the natural circulation, boron mixing, and cooldown capability of these plants.

  2. A study of natural circulation in the evaporator of a horizontal-tube heat recovery steam generator

    NASA Astrophysics Data System (ADS)

    Roslyakov, P. V.; Pleshanov, K. A.; Sterkhov, K. V.

    2014-07-01

    Results obtained from investigations of stable natural circulation in an intricate circulation circuit with a horizontal layout of the tubes of evaporating surface having a negative useful head are presented. The possibility of making a shift from using multiple forced circulation organized by means of a circulation pump to natural circulation in vertical heat recovery steam generator is estimated. Criteria for characterizing the performance reliability and efficiency of a horizontal evaporator with negative useful head are proposed. The influence of various design solutions on circulation robustness is considered. With due regard of the optimal parameters, the most efficient and least costly methods are proposed for achieving more stable circulation in a vertical heat recovery steam generator when a shift is made from multiple forced to natural circulation. A procedure for calculating the circulation parameters and an algorithm for checking evaporator performance reliability are developed, and recommendations for the design of heat recovery steam generator, nonheated parts of natural circulation circuit, and evaporating surface are suggested.

  3. Study of natural circulation in a VHTR after a LOFA using different turbulence models

    SciTech Connect

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

    2013-10-01

    Natural convection currents in the core are anticipated in the event of the failure of the gas circulator in a prismatic gas-cooled very high temperature reactor (VHTR). The paths that the helium coolant takes in forming natural circulation loops and the effective heat transport are of interest. The heated flow in the reactor core is turbulent during normal operating conditions and at the beginning of the LOFA with forced convection, but the flow may significantly be slowed down after the event and laminarized with mixed convection. In the present study, the potential occurrence and effective heat transport of natural circulation are demonstrated using computational fluid dynamic (CFD) calculations with different turbulence models as well as laminar flow. Validations and recommendation on turbulence model selection are conducted. The study concludes that large loop natural convection is formed due to the enhanced turbulence levels by the buoyancy effect and the turbulent regime near the interface of upper plenum and flow channels increases the flow resistance for channel flows entering upper plenum and thus less heat can be removed from the core than the prediction by laminar flow assumption.

  4. Evaluation Method for Core Thermohydraulics during Natural Circulation in Fast Reactors

    NASA Astrophysics Data System (ADS)

    Kamide, Hideki; Nagasawa, Kazuyoshi; Kimura, Nobuyuki; Miyakoshi, Hiroyuki

    Decay heat removal using natural circulation is one of significant functions for a reactor. As the decay heat removal system, a direct reactor auxiliary cooling system has been selected in current designs of fast reactors. In this system, cold sodium is provided in an upper plenum of reactor vessel and it covers the reactor core outlet. The cold sodium can penetrate into the gap region between the subassemblies. This gap flow is referred as inter-wrapper flow (IWF). A numerical estimation method for such phenomena was developed, which modeled each subassembly as a rectangular duct with gap region and also the upper plenum. This numerical simulation method was verified by a sodium test and also a water test. We applied this method to the natural circulation in a 600 MWe class fast reactor. The temperature in the core strongly depended on IWF, flow redistribution in the core, and inter-subassembly heat transfer.

  5. Enhancement of natural circulation type domestic solar hot water system performance by using a wind turbine

    NASA Astrophysics Data System (ADS)

    Ramasamy, K. K.; Srinivasan, P. S. S.

    2011-08-01

    Performance improvement of existing 200 litres capacity natural convection type domestic solar hot water system is attempted. A two-stage centrifugal pump driven by a vertical axis windmill having Savonius type rotor is added to the fluid loop. The windmill driven pump circulates the water through the collector. The system with necessary instrumentation is tested over a day. Tests on Natural Circulation System (NCS) mode and Wind Assisted System (WAS) mode are carried out during January, April, July and October, 2009. Test results of a clear day are reported. Daily average efficiency of 25-28 % during NCS mode and 33-37 % during WAS mode are obtained. With higher wind velocities, higher collector flow rates and hence higher efficiencies are obtained. In general, WAS mode provides improvements in efficiency when compared to NCS mode.

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

    SciTech Connect

    Massoud, M

    1987-01-01

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

  7. [Raynaud's phenomenon].

    PubMed

    Piérard-Franchimont, C; Piérard, G E; Hermanns-Lê, T

    2012-12-01

    Raynaud's phenomenon is a vascular acrosyndrome caused by a variety of diseases. There is a distinction between the idiopathic Raynaud's disease, the secondary types and the suspicious idiopathic Raynaud's phenomenon.

  8. Parametric study of natural circulation flow in molten salt fuel in molten salt reactor

    SciTech Connect

    Pauzi, Anas Muhamad; Cioncolini, Andrea; Iacovides, Hector

    2015-04-29

    The Molten Salt Reactor (MSR) is one of the most promising system proposed by Generation IV Forum (GIF) for future nuclear reactor systems. Advantages of the MSR are significantly larger compared to other reactor system, and is mainly achieved from its liquid nature of fuel and coolant. Further improvement to this system, which is a natural circulating molten fuel salt inside its tube in the reactor core is proposed, to achieve advantages of reducing and simplifying the MSR design proposed by GIF. Thermal hydraulic analysis on the proposed system was completed using a commercial computation fluid dynamics (CFD) software called FLUENT by ANSYS Inc. An understanding on theory behind this unique natural circulation flow inside the tube caused by fission heat generated in molten fuel salt and tube cooling was briefly introduced. Currently, no commercial CFD software could perfectly simulate natural circulation flow, hence, modeling this flow problem in FLUENT is introduced and analyzed to obtain best simulation results. Results obtained demonstrate the existence of periodical transient nature of flow problem, hence improvements in tube design is proposed based on the analysis on temperature and velocity profile. Results show that the proposed system could operate at up to 750MW core power, given that turbulence are enhanced throughout flow region, and precise molten fuel salt physical properties could be defined. At the request of the authors and the Proceedings Editor the name of the co-author Andrea Cioncolini was corrected from Andrea Coincolini. The same name correction was made in the Acknowledgement section on page 030004-10 and in reference number 4. The updated article was published on 11 May 2015.

  9. Parametric study of natural circulation flow in molten salt fuel in molten salt reactor

    NASA Astrophysics Data System (ADS)

    Pauzi, Anas Muhamad; Cioncolini, Andrea; Iacovides, Hector

    2015-04-01

    The Molten Salt Reactor (MSR) is one of the most promising system proposed by Generation IV Forum (GIF) for future nuclear reactor systems. Advantages of the MSR are significantly larger compared to other reactor system, and is mainly achieved from its liquid nature of fuel and coolant. Further improvement to this system, which is a natural circulating molten fuel salt inside its tube in the reactor core is proposed, to achieve advantages of reducing and simplifying the MSR design proposed by GIF. Thermal hydraulic analysis on the proposed system was completed using a commercial computation fluid dynamics (CFD) software called FLUENT by ANSYS Inc. An understanding on theory behind this unique natural circulation flow inside the tube caused by fission heat generated in molten fuel salt and tube cooling was briefly introduced. Currently, no commercial CFD software could perfectly simulate natural circulation flow, hence, modeling this flow problem in FLUENT is introduced and analyzed to obtain best simulation results. Results obtained demonstrate the existence of periodical transient nature of flow problem, hence improvements in tube design is proposed based on the analysis on temperature and velocity profile. Results show that the proposed system could operate at up to 750MW core power, given that turbulence are enhanced throughout flow region, and precise molten fuel salt physical properties could be defined. At the request of the authors and the Proceedings Editor the name of the co-author Andrea Cioncolini was corrected from Andrea Coincolini. The same name correction was made in the Acknowledgement section on page 030004-10 and in reference number 4. The updated article was published on 11 May 2015.

  10. Natural circulation loop using liquid nitrogen for cryo-detection system

    SciTech Connect

    Choi, Yeon Suk

    2014-01-29

    The natural circulation loop is designed for the cryogenic insert in a Fourier transform ion cyclotron resonance (FTICR) mass spectrometer. Sensitivity is the key parameter of a FTICR mass spectrometer and the cryo-cooling of the pre-amplifier can reduce the thermal noise level and thereby improve the signal-to-noise ratio. The pre-amplifier consisted of non-magnetic materials is thermally connected to the cooling loop which is passing through the flange maintaining ultra-high vacuum in the ion cell. The liquid nitrogen passes through inside of the loop to cool the pre-amplifier indirectly. At the end, a cryocooler is located to re-condense nitrogen vapor generated due to the heat from the pre-amplifier. The circulating fluid removes heat from the pre-amplifier and transports it to the cryocooler or heat sink. In this paper the natural circulation loop for cryogenic pre-amplifier is introduced for improving the sensitivity of cryo-detector. In addition, the initial cool-down of the system by a cryocooler is presented and the temperature of the radiation shield is discussed with respect to the thickness of shield and the thermal radiation load.

  11. Investigation of Natural Circulation Instability and Transients in Passively Safe Small Modular Reactors

    SciTech Connect

    Ishii, Mamoru

    2016-11-30

    The NEUP funded project, NEUP-3496, aims to experimentally investigate two-phase natural circulation flow instability that could occur in Small Modular Reactors (SMRs), especially for natural circulation SMRs. The objective has been achieved by systematically performing tests to study the general natural circulation instability characteristics and the natural circulation behavior under start-up or design basis accident conditions. Experimental data sets highlighting the effect of void reactivity feedback as well as the effect of power ramp-up rate and system pressure have been used to develop a comprehensive stability map. The safety analysis code, RELAP5, has been used to evaluate experimental results and models. Improvements to the constitutive relations for flashing have been made in order to develop a reliable analysis tool. This research has been focusing on two generic SMR designs, i.e. a small modular Simplified Boiling Water Reactor (SBWR) like design and a small integral Pressurized Water Reactor (PWR) like design. A BWR-type natural circulation test facility was firstly built based on the three-level scaling analysis of the Purdue Novel Modular Reactor (NMR) with an electric output of 50 MWe, namely NMR-50, which represents a BWR-type SMR with a significantly reduced reactor pressure vessel (RPV) height. The experimental facility was installed with various equipment to measure thermalhydraulic parameters such as pressure, temperature, mass flow rate and void fraction. Characterization tests were performed before the startup transient tests and quasi-steady tests to determine the loop flow resistance. The control system and data acquisition system were programmed with LabVIEW to realize the realtime control and data storage. The thermal-hydraulic and nuclear coupled startup transients were performed to investigate the flow instabilities at low pressure and low power conditions for NMR-50. Two different power ramps were chosen to study the effect of startup

  12. Changes in equatorial zonal circulations and precipitation in the context of the global warming and natural modes

    NASA Astrophysics Data System (ADS)

    Kim, Byeong-Hee; Ha, Kyung-Ja

    2017-07-01

    The strengthening and westward shift of Pacific Walker Circulation (PWC) is observed during the recent decades. However, the relative roles of global warming and natural variability on the change in PWC unclearly remain. By conducting numerical atmospheric general circulation model (AGCM) experiments using the spatial SST patterns in the global warming and natural modes which are obtained by the multi-variate EOF analysis from three variables including precipitation, sea surface temperature (SST), and divergent zonal wind, we indicated that the westward shift and strengthening of PWC are caused by the global warming SST pattern in the global warming mode and the negative Interdecadal Pacific Oscillation-like SST pattern in the natural mode. The SST distribution of the Pacific Ocean (PO) has more influence on the changes in equatorial zonal circulations and tropical precipitation than that of the Indian Ocean (IO) and Atlantic Ocean (AO). The change in precipitation is also related to the equatorial zonal circulations variation through the upward and downward motions of the circulations. The IO and AO SST anomalies in the global warming mode can affect on the changes in equatorial zonal circulations, but the influence of PO SST disturbs the changes in Indian Walker Circulation and Atlantic Walker Circulation which are affected by the anomalous SST over the IO and AO. The zonal shift of PWC is found to be highly associated with a zonal gradient of SST over the PO through the idealized numerical AGCM experiments and predictions of CMIP5 models.

  13. Two-phase flow stability structure in a natural circulation system

    SciTech Connect

    Zhou, Zhiwei

    1995-09-01

    The present study reports a numerical analysis of two-phase flow stability structures in a natural circulation system with two parallel, heated channels. The numerical model is derived, based on the Galerkin moving nodal method. This analysis is related to some design options applicable to integral heating reactors with a slightly-boiling operation mode, and is also of general interest to similar facilities. The options include: (1) Symmetric heating and throttling; (2) Asymmetric heating and symmetric throttling; (3) Asymmetric heating and throttling. The oscillation modes for these variants are discussed. Comparisons with the data from the INET two-phase flow stability experiment have qualitatively validated the present analysis.

  14. Research of natural circulation in the experimental helium loop of STU

    NASA Astrophysics Data System (ADS)

    František, Urban; František, RidzoÅ; Branislav, Knížat; Róbert, Olšiak; Jozef, Bereznai; Peter, Mlynár

    2017-09-01

    On the STU experimental helium loop, natural circulation of the helium by residual thermal power of the reactor up to 220 kW, temperature of the helium from l50°C to 520°C and helium pressure up to 7,0 MPa is investigated. Selected measurements are analysed. Measurements realized on experimental device with different operational states of the STU helium loop can be used for cooling loops design corrections and validation of the computational algorithms of the passive heat removal from ALLEGRO nuclear reactor.

  15. Experimental and analytical investigation of two-phase stability in a natural circulation loop

    SciTech Connect

    Dimmick, G.R.; Chatoorgoon, V.

    1985-01-01

    The authors are currently studying the feasibility of pool type reactors, for heating commercial buildings. To investigate thermal hydraulic aspects of reactor design, including the stability under extreme conditions, an electrically heated natural circulation loop was designed and constructed. Experimental tests with this loop show that it is stable under all single phase conditions, an expected result. In tests with two phases present in the circuit, different types of behaviour were observed depending on the experimental conditions. These were either stable flow, non-divergent oscillating flow or divergent oscillating flow. All of these type of behaviour were successfully simulated using the newly developed SPORTS stability computer code.

  16. CFD analyses of natural circulation in the air-cooled reactor cavity cooling system

    SciTech Connect

    Hu, R.; Pointer, W. D.

    2013-07-01

    The Natural Convection Shutdown Heat Removal Test Facility (NSTF) is currently being built at Argonne National Laboratory, to evaluate the feasibility of the passive Reactor Cavity Cooling System (RCCS) for Next Generation Nuclear Plant (NGNP). CFD simulations have been applied to evaluate the NSTF and NGNP RCCS designs. However, previous simulations found that convergence was very difficult to achieve in simulating the complex natural circulation. To resolve the convergence issue and increase the confidence of the CFD simulation results, additional CFD simulations were conducted using a more detailed mesh and a different solution scheme. It is found that, with the use of coupled flow and coupled energy models, the convergence can be greatly improved. Furthermore, the effects of convection in the cavity and the effects of the uncertainty in solid surface emissivity are also investigated. (authors)

  17. Design study of lead bismuth cooled fast reactors and capability of natural circulation

    NASA Astrophysics Data System (ADS)

    Oktamuliani, Sri; Su'ud, Zaki

    2015-09-01

    A preliminary study designs SPINNOR (Small Power Reactor, Indonesia, No On-Site Refueling) liquid metal Pb-Bi cooled fast reactors, fuel (U, Pu)N, 150 MWth have been performed. Neutronic calculation uses SRAC which is designed cylindrical core 2D (R-Z) 90 × 135 cm, on the core fuel composed of heterogeneous with percentage difference of PuN 10, 12, 13% and the result of calculation is effective neutron multiplication 1.0488. Power density distribution of the output SRAC is generated for thermal hydraulic calculation using Delphi based on Pascal language that have been developed. The research designed a reactor that is capable of natural circulation at inlet temperature 300 °C with variation of total mass flow rate. Total mass flow rate affect pressure drop and temperature outlet of the reactor core. The greater the total mass flow rate, the smaller the outlet temperature, but increase the pressure drop so that the chimney needed more higher to achieve natural circulation or condition of the system does not require a pump. Optimization of the total mass flow rate produces optimal reactor design on the total mass flow rate of 5000 kg/s with outlet temperature 524,843 °C but require a chimney of 6,69 meters.

  18. Design study of lead bismuth cooled fast reactors and capability of natural circulation

    SciTech Connect

    Oktamuliani, Sri Su’ud, Zaki

    2015-09-30

    A preliminary study designs SPINNOR (Small Power Reactor, Indonesia, No On-Site Refueling) liquid metal Pb-Bi cooled fast reactors, fuel (U, Pu)N, 150 MWth have been performed. Neutronic calculation uses SRAC which is designed cylindrical core 2D (R-Z) 90 × 135 cm, on the core fuel composed of heterogeneous with percentage difference of PuN 10, 12, 13% and the result of calculation is effective neutron multiplication 1.0488. Power density distribution of the output SRAC is generated for thermal hydraulic calculation using Delphi based on Pascal language that have been developed. The research designed a reactor that is capable of natural circulation at inlet temperature 300 °C with variation of total mass flow rate. Total mass flow rate affect pressure drop and temperature outlet of the reactor core. The greater the total mass flow rate, the smaller the outlet temperature, but increase the pressure drop so that the chimney needed more higher to achieve natural circulation or condition of the system does not require a pump. Optimization of the total mass flow rate produces optimal reactor design on the total mass flow rate of 5000 kg/s with outlet temperature 524,843 °C but require a chimney of 6,69 meters.

  19. Thermalhydraulic calculation for boiling water reactor and its natural circulation component

    SciTech Connect

    Trianti, Nuri Nurjanah,; Su’ud, Zaki; Arif, Idam; Permana, Sidik

    2015-09-30

    Thermalhydraulic of reactor core is the thermal study on fluids within the core reactor, i.e. analysis of the thermal energy transfer process produced by fission reaction from fuel to the reactor coolant. This study include of coolant temperature and reactor power density distribution. The purposes of this analysis in the design of nuclear power plant are to calculate the coolant temperature distribution and the chimney height so natural circulation could be occurred. This study was used boiling water reactor (BWR) with cylinder type reactor core. Several reactor core properties such as linear power density, mass flow rate, coolant density and inlet temperature has been took into account to obtain distribution of coolant density, flow rate and pressure drop. The results of calculation are as follows. Thermal hydraulic calculations provide the uniform pressure drop of 1.1 bar for each channels. The optimum mass flow rate to obtain the uniform pressure drop is 217g/s. Furthermore, from the calculation it could be known that outlet temperature is 288°C which is the saturated fluid’s temperature within the system. The optimum chimney height for natural circulation within the system is 14.88 m.

  20. [Raynaud's phenomenon].

    PubMed

    Saavedra Salinas, Miguel Ángel; Carrillo Vázquez, Sandra Miriam

    2006-11-01

    Raynaud's phenomenon is characterized by repeated daily attacks of ischemia followed by reperfusion at the acrallevel. It is a frequent syndrome found in medical practice; and it can be considered as primary or secondary to other conditions, including rheumatic autoimmune diseases. Current classification had clinical and therapeutic implications. Careful clinical evaluation is the most reliable and reproducible method in the diagnosis of Raynaud's phenomenon. Several risk factors had been associated in the genesis of Raynaud's phenomenon; however, its pathogenesis remains elusive although recently, considerable progress in disease mechanism had been described. Such advances are directing new lines of therapy.

  1. Raynaud's phenomenon.

    PubMed

    Hughes, Michael; Herrick, Ariane L

    2016-02-01

    Raynaud's phenomenon (RP) is a major cause of pain and disability in patients with autoimmune connective tissue diseases (CTDs), particularly systemic sclerosis (SSc). The clinician must perform a comprehensive clinical assessment in patients with RP to differentiate between primary (idiopathic) and secondary RP, in particular (for rheumatologists), secondary to an autoimmune CTD, as both the prognosis and treatment may differ significantly. Key investigations are nailfold capillaroscopy and testing for autoantibodies (in particular, those associated with SSc). Patients with RP and either abnormal nailfold capillaroscopy or an SSc-specific antibody (and especially with both) have a high risk of transitioning to an autoimmune CTD. Both nailfold capillaroscopy and autoantibody specificity may help the clinician in predicting organ-based complications. The management of CTD-associated RP requires a multifaceted approach to treatment, including patient education and conservative ('non-drug') measures. Patients with CTD-associated RP often require pharmacological treatment, which in the first instance is usually a calcium channel blocker, although other agents can be used. There is an increasing tendency to use phosphodiesterase type 5 inhibitors early in the treatment of CTD-associated RP. Oral therapies are commonly associated with side effects (often due to systemic vasodilation) that may result in failure of dose escalation and/or permanent discontinuation. Intravenous prostanoid therapy and surgery (e.g., botulinum toxin injection and digital sympathectomy) can be considered in severe RP. Patients with CTD-associated RP can develop a number of ischaemic digital complications (primarily ulcers and critical ischaemia), which may be associated with significant tissue loss. Future research is required to increase the understanding of the pathogenesis and natural history of RP (to drive therapeutic advances), and to explore/develop drug therapies, including those that

  2. Pathogenesis of Raynaud's phenomenon.

    PubMed

    Herrick, A L

    2005-05-01

    The pathogenesis of Raynaud's phenomenon is not fully understood. However, the last 20 yr have witnessed enormous increases in our understanding of different mechanisms which, singly or in combination, may contribute. A key point is that Raynaud's phenomenon can be either primary (idiopathic) or secondary to a number of underlying conditions, and that the pathogenesis and pathophysiology vary between these conditions. This review concentrates upon those subtypes of Raynaud's phenomenon of most interest to rheumatologists: systemic sclerosis-related Raynaud's phenomenon, primary Raynaud's phenomenon and Raynaud's phenomenon secondary to hand-arm vibration syndrome. In this review, I shall discuss the main mechanisms thought to be important in pathophysiology under the three broad headings of 'vascular', 'neural' and 'intravascular'. While these are false distinctions because all interrelate, they facilitate discussion of the key elements: the blood vessel wall (particularly the endothelium), the neural control of vascular tone, and the many circulating factors which can impair blood flow and/or cause endothelial injury. Vascular abnormalities include those of both structure and function. Neural abnormalities include deficiency of the vasodilator calcitonin gene-related peptide (released from sensory afferents), alpha(2)-adrenoreceptor activation (possibly with up-regulation of the normally 'silent' alpha(2C)-adrenoreceptor) and a central nervous system component. Intravascular abnormalities include platelet activation, impaired fibrinolysis, increased viscosity and probably oxidant stress. As our understanding of the pathophysiology of Raynaud's phenomenon increases, so do our possibilities for identifying effective treatments.

  3. Natural Circulation Level Optimization and the Effect during ULOF Accident in the SPINNOR Reactors

    SciTech Connect

    Abdullah, Ade Gafar; Su'ud, Zaki; Kurniadi, Rizal; Kurniasih, Neny; Yulianti, Yanti

    2010-12-23

    Natural circulation level optimization and the effect during loss of flow accident in the 250 MWt MOX fuelled small Pb-Bi Cooled non-refueling nuclear reactors (SPINNOR) have been performed. The simulation was performed using FI-ITB safety code which has been developed in ITB. The simulation begins with steady state calculation of neutron flux, power distribution and temperature distribution across the core, hot pool and cool pool, and also steam generator. When the accident is started due to the loss of pumping power the power distribution and the temperature distribution of core, hot pool and cool pool, and steam generator change. Then the feedback reactivity calculation is conducted, followed by kinetic calculation. The process is repeated until the optimum power distribution is achieved. The results show that the SPINNOR reactor has inherent safety capability against this accident.

  4. Natural circulation in a VVER reactor geometry: Experiments with the PACTEL facility and Cathare simulations

    SciTech Connect

    Raussi, P.; Kainulainen, S.; Kouhia, J.

    1995-09-01

    There are some 40 reactors based on the VVER design in use. Database available for computer code assessment for VVER reactors is rather limited. Experiments were conducted to study natural circulation behaviour in the PACTEL facility, a medium-scale integral test loop patterned after VVER pressurized water reactors. Flow behaviour over a range of coolant inventories was studied with a small-break experiment. In the small-break experiments, flow stagnation and system repressurization were observed when the water level in the upper plenum fell below the entrances to the hot legs. The cause was attributed to the hot leg loop seals, which are a unique feature of the VVER geometry. At low primary inventories, core cooling was achieved through the boiler-condenser mode. The experiment was simulated using French thermalhydraulic system code CATHARE.

  5. Circulation of images and graphic practices in Renaissance natural history: the example of Conrad Gessner.

    PubMed

    Egmond, Florike; Kusukawa, Sachiko

    2016-01-01

    Conrad Gessner's Historia animalium is a compilation of information from a variety of sources: friends, correspondents, books, broadsides, drawings, as well as his own experience. The recent discovery of a cache of drawings at Amsterdam originally belonging to Gessner has added a new dimension for research into the role of images in Gessner's study of nature. In this paper, we examine the drawings that were the basis of the images in the volume of fishes. We uncovered several cases where there were multiple copies of the same drawing of a fish (rather than multiple drawings of the samefish), which problematizes the notion of unique "original" copies and their copies. While we still know very little about the actual mechanism of, or people involved in, commissioning or generating copies of drawings, their very existence suggests that the images functioned as an important medium in the circulation of knowledge in the early modern period.

  6. Heat and Mass Transfer in Nucleate Boiling Regime of HE I in a Natural Circulation Loop

    NASA Astrophysics Data System (ADS)

    Benkheira, L.; Souhar, M.; Baudouy, B.

    2006-04-01

    This paper is devoted to the experimental study of He I natural circulation loop under nucleate boiling conditions, which simulates the cooling system of the 4 Tesla superconducting solenoid CMS under construction at CERN for the LHC. The test section consists of an electrically heated copper tube of 0.010 m ID and 0.95 m long. Uniform heat fluxes in the range of 0-2000 W/m2 were employed. All data were generated near atmospheric pressure. Reported are results of the boiling curves and the effect of heat flux on the heat transfer coefficient under boiling. An attempt is carried out to predict the boiling incipience and to correlate the heat transfer coefficient based on the combining effect of forced convection and nucleate boiling by a power-type asymptotic model.

  7. Helium I heat transfer in a small natural circulation loop with self-sustaining recondensation

    NASA Astrophysics Data System (ADS)

    Song, Yu; Four, Aurélien; Baudouy, Bertrand

    2014-01-01

    Heat transfer of helium I in a natural circulation loop is experimentally studied around atmospheric pressure. The test section of the loop has an inner diameter of 4 mm and a height of 23 cm and can be uniformly heated by wire heater. On top of the loop, a condenser is mounted and thermally connected to the second-stage of a 1.5 W at 4.2 K GM cryocooler. Helium can be recondensed in the condenser, where the pressure is regulated around the atmospheric pressure. While the dissipated heat flux is increased from 0 to 1 W, one encounters the different heat transfer regimes as single phase liquid convection, two phase nucleate boiling and single phase vapor convection. The wall superheat varies up to 11 K in the single phase vapor convection regime. The wall temperature measurement allows obtaining the boiling curve and determining the heat transfer coefficient.

  8. Modeling of thermohydraulic transients in a boiling helium natural circulation loop

    NASA Astrophysics Data System (ADS)

    Furci, H.; Baudouy, B.

    2016-12-01

    Boiling helium natural circulation loops are a cooling option for superconducting magnets. Previous studies on the field have provided a thorough understanding of their steady state behavior in all boiling regimes. Recent experimental research has lead to the understanding of their transient behavior. In particular, it highlights the impact of the thermohydraulic evolution of the circuit on the onset of transient boiling crisis, which represents a limitation of the cooling system. Hence, the need of modeling this aspect of these systems. In this work we present modeling options of two-phase helium loops departing from the homogeneous equilibrium two-phase flow model. Reasonable additional assumptions are introduced to obtain a simplified model and the effect of these assumptions is evaluated by comparison with the solution of the non-simplified equations system. These methods are compared to experimental data to analyze their success and limitations.

  9. Buoyancy Driven Coolant Mixing Studies of Natural Circulation Flows at the ROCOM Test Facility Using ANSYS CFX

    SciTech Connect

    Hohne, Thomas; Kliem, Soren; Rohde, Ulrich; Weiss, Frank-Peter

    2006-07-01

    Coolant mixing in the cold leg, downcomer and the lower plenum of pressurized water reactors is an important phenomenon mitigating the reactivity insertion into the core. Therefore, mixing of the de-borated slugs with the ambient coolant in the reactor pressure vessel was investigated at the four loop 1:5 scaled ROCOM mixing test facility. Thermal hydraulics analyses showed, that weakly borated condensate can accumulate in particular in the pump loop seal of those loops, which do not receive safety injection. After refilling of the primary circuit, natural circulation in the stagnant loops can re-establish simultaneously and the de-borated slugs are shifted towards the reactor pressure vessel (RPV). In the ROCOM experiments, the length of the flow ramp and the initial density difference between the slugs and the ambient coolant was varied. From the test matrix experiments with 0 resp. 2% density difference between the de-borated slugs and the ambient coolant were used to validate the CFD software ANSYS CFX. To model the effects of turbulence on the mean flow a higher order Reynolds stress turbulence model was employed and a mesh consisting of 6.4 million hybrid elements was utilized. Only the experiments and CFD calculations with modeled density differences show a stratification in the downcomer. Depending on the degree of density differences the less dense slugs flow around the core barrel at the top of the downcomer. At the opposite side the lower borated coolant is entrained by the colder safety injection water and transported to the core. The validation proves that ANSYS CFX is able to simulate appropriately the flow field and mixing effects of coolant with different densities. (authors)

  10. Two-phase flow instability and dryout in parallel channels in natural circulation

    SciTech Connect

    Duffey, R.B.; Rohatgi, U.S.; Hughes, E.D.

    1993-06-01

    The unique feature of parallel channel flows is that the pressure drop or driving head for the flow is maintained constant across any given channel by the flow in all the others, or by having a large downcomer or bypass in a natural circulation loop. This boundary condition is common in all heat exchangers, reactor cores and boilers, it is well known that the two-phase flow in parallel channels can exhibit both so-called static and dynamic instability. This leads to the question of the separability of the flow and pressure drop boundary conditions in the study of stability and dryout. For the areas of practical interest, the flow can be considered as incompressible. The dynamic instability is characterized by density (kinematic) or continuity waves, and the static instability by inertial (pressure drop) or manometric escalations. The static has been considered to be the zero-frequency or lowest mode of the dynamic case. We briefly review the status of the existing literature on both parallel channel static and dynamic instability, and the latest developments in theory and experiment. The difference between the two derivations lies in the retention of the time-dependent terms in the conservation equations. The effects and impact of design options are also discussed. Since dryout in parallel systems follows instability, it has been traditional to determine the dryout power for a parallel channel by testing a single channel with a given (inlet) flow boundary condition without particular regard for the pressure drop. Thus all modern dryout correlations are based on constant or fixed flow tests, a so-called hard inlet, and subchannel and multiple bundle effects are corrected for separately. We review the thinking that lead to this approach, and suggest that for all multiple channel and natural circulation systems close attention should be paid to the actual (untested) pressure drop conditions. A conceptual formulation is suggested as a basis for discussion.

  11. Development of the FHR advanced natural circulation analysis code and application to FHR safety analysis

    DOE PAGES

    Guo, Z.; Zweibaum, N.; Shao, M.; ...

    2016-04-19

    The University of California, Berkeley (UCB) is performing thermal hydraulics safety analysis to develop the technical basis for design and licensing of fluoride-salt-cooled, high-temperature reactors (FHRs). FHR designs investigated by UCB use natural circulation for emergency, passive decay heat removal when normal decay heat removal systems fail. The FHR advanced natural circulation analysis (FANCY) code has been developed for assessment of passive decay heat removal capability and safety analysis of these innovative system designs. The FANCY code uses a one-dimensional, semi-implicit scheme to solve for pressure-linked mass, momentum and energy conservation equations. Graph theory is used to automatically generate amore » staggered mesh for complicated pipe network systems. Heat structure models have been implemented for three types of boundary conditions (Dirichlet, Neumann and Robin boundary conditions). Heat structures can be composed of several layers of different materials, and are used for simulation of heat structure temperature distribution and heat transfer rate. Control models are used to simulate sequences of events or trips of safety systems. A proportional-integral controller is also used to automatically make thermal hydraulic systems reach desired steady state conditions. A point kinetics model is used to model reactor kinetics behavior with temperature reactivity feedback. The underlying large sparse linear systems in these models are efficiently solved by using direct and iterative solvers provided by the SuperLU code on high performance machines. Input interfaces are designed to increase the flexibility of simulation for complicated thermal hydraulic systems. In conclusion, this paper mainly focuses on the methodology used to develop the FANCY code, and safety analysis of the Mark 1 pebble-bed FHR under development at UCB is performed.« less

  12. Development of the FHR advanced natural circulation analysis code and application to FHR safety analysis

    SciTech Connect

    Guo, Z.; Zweibaum, N.; Shao, M.; Huddar, L. R.; Peterson, P. F.; Qiu, S.

    2016-04-19

    The University of California, Berkeley (UCB) is performing thermal hydraulics safety analysis to develop the technical basis for design and licensing of fluoride-salt-cooled, high-temperature reactors (FHRs). FHR designs investigated by UCB use natural circulation for emergency, passive decay heat removal when normal decay heat removal systems fail. The FHR advanced natural circulation analysis (FANCY) code has been developed for assessment of passive decay heat removal capability and safety analysis of these innovative system designs. The FANCY code uses a one-dimensional, semi-implicit scheme to solve for pressure-linked mass, momentum and energy conservation equations. Graph theory is used to automatically generate a staggered mesh for complicated pipe network systems. Heat structure models have been implemented for three types of boundary conditions (Dirichlet, Neumann and Robin boundary conditions). Heat structures can be composed of several layers of different materials, and are used for simulation of heat structure temperature distribution and heat transfer rate. Control models are used to simulate sequences of events or trips of safety systems. A proportional-integral controller is also used to automatically make thermal hydraulic systems reach desired steady state conditions. A point kinetics model is used to model reactor kinetics behavior with temperature reactivity feedback. The underlying large sparse linear systems in these models are efficiently solved by using direct and iterative solvers provided by the SuperLU code on high performance machines. Input interfaces are designed to increase the flexibility of simulation for complicated thermal hydraulic systems. In conclusion, this paper mainly focuses on the methodology used to develop the FANCY code, and safety analysis of the Mark 1 pebble-bed FHR under development at UCB is performed.

  13. Thermalhydraulic aspects of decay heat removal by natural circulation in fast reactor systems

    SciTech Connect

    Roy, C.M.; Hetsroni, G.; Banerjee, S.

    1990-01-01

    Natural convection in enclosures have been studied numerically to provide insight into the scaling laws existing for removal of decay heat in Liquid Metal Fast Reactors (LMFR). Specifically, 3-D simulations have been carried out for natural circulation in a cylinder with small aspect ratio (of the order of 0.5). These results have been compared to the results of an experiment conducted by UCSB, in collaboration with GE, to provide benchmark data for code validation. Parametric studies have been conducted to establish the validity of a 3-D Finite difference code that uses body-fitted grids for simulations of complex geometries. Further, numerical simulations have been carried out to demonstrate the importance of 3-D computer codes as tools in the design and scale-up of prototype LMFRs. It has been shown that the geometry of the passive safety systems is key to safe operation of LMFRs under shutdown conditions. The key phenomena that occur in such situations have bee studied and the available experimental studies have been identified. The future direction for modeling of natural convection recirculating flows in confined enclosures has been proposed. 31 refs.

  14. Thermalhydraulic aspects of decay heat removal by natural circulation in fast reactor systems. Final report

    SciTech Connect

    Roy, C.M.; Hetsroni, G.; Banerjee, S.

    1990-12-31

    Natural convection in enclosures have been studied numerically to provide insight into the scaling laws existing for removal of decay heat in Liquid Metal Fast Reactors (LMFR). Specifically, 3-D simulations have been carried out for natural circulation in a cylinder with small aspect ratio (of the order of 0.5). These results have been compared to the results of an experiment conducted by UCSB, in collaboration with GE, to provide benchmark data for code validation. Parametric studies have been conducted to establish the validity of a 3-D Finite difference code that uses body-fitted grids for simulations of complex geometries. Further, numerical simulations have been carried out to demonstrate the importance of 3-D computer codes as tools in the design and scale-up of prototype LMFRs. It has been shown that the geometry of the passive safety systems is key to safe operation of LMFRs under shutdown conditions. The key phenomena that occur in such situations have bee studied and the available experimental studies have been identified. The future direction for modeling of natural convection recirculating flows in confined enclosures has been proposed. 31 refs.

  15. Investigation of natural circulation instability and transients in passively safe novel modular reactor

    NASA Astrophysics Data System (ADS)

    Shi, Shanbin

    The Purdue Novel Modular Reactor (NMR) is a new type small modular reactor (SMR) that belongs to the design of boiling water reactor (BWR). Specifically, the NMR is one third the height and area of a conventional BWR reactor pressure vessel (RPV) with an electric output of 50 MWe. The fuel cycle length of the NMR-50 is extended up to 10 years due to optimized neutronics design. The NMR-50 is designed with double passive engineering safety system. However, natural circulation BWRs (NCBWR) could experience certain operational difficulties due to flow instabilities that occur at low pressure and low power conditions. Static instabilities (i.e. flow excursion (Ledinegg) instability and flow pattern transition instability) and dynamic instabilities (i.e. density wave instability and flashing/condensation instability) pose a significant challenge in two-phase natural circulation systems. In order to experimentally study the natural circulation flow instability, a proper scaling methodology is needed to build a reduced-size test facility. The scaling analysis of the NMR uses a three-level scaling method, which was developed and applied for the design of the Purdue Multi-dimensional Integral Test Assembly (PUMA). Scaling criteria is derived from dimensionless field equations and constitutive equations. The scaling process is validated by the RELAP5 analysis for both steady state and startup transients. A new well-scaled natural circulation test facility is designed and constructed based on the scaling analysis of the NMR-50. The experimental facility is installed with different equipment to measure various thermal-hydraulic parameters such as pressure, temperature, mass flow rate and void fraction. Characterization tests are performed before the startup transient tests and quasi-steady tests to determine the loop flow resistance. The controlling system and data acquisition system are programmed with LabVIEW to realize the real-time control and data storage. The thermal

  16. Stability analysis of a natural circulation lead-cooled fast reactor

    NASA Astrophysics Data System (ADS)

    Lu, Qiyue

    This dissertation is aimed at nuclear-coupled thermal hydraulics stability analysis of a natural circulation lead cooled fast reactor design. The stability concerns arise from the fact that natural circulation operation makes the system susceptible to flow instabilities similar to those observed in boiling water reactors. In order to capture the regional effects, modal expansion method which incorporates higher azimuthal modes is used to model the neutronics part of the system. A reduced order model is used in this work for the thermal-hydraulics. Consistent with the number of heat exchangers (HXs), the reactor core is divided into four equal quadrants. Each quadrant has its corresponding external segments such as riser, plenum, pipes and HX forming an equivalent 1-D closed loop. The local pressure loss along the loop is represented by a lumped friction factor. The heat transfer process in the HX is represented by a model for the coolant temperature at the core inlet that depends on the coolant temperature at the core outlet and the coolant velocity. Additionally, time lag effects are incorporated into this HX model due to the finite coolant speed. A conventional model is used for the fuel pin heat conduction to couple the neutronics and thermal-hydraulics. The feedback mechanisms include Doppler, axial/radial thermal expansion and coolant density effects. These effects are represented by a linear variation of the macroscopic cross sections with the fuel temperature. The weighted residual method is used to convert the governing PDEs to ODEs. Retaining the first and second modes, leads to six ODEs for neutronics, and five ODEs for the thermal-hydraulics in each quadrant. Three models are developed. These are: 1) natural circulation model with a closed coolant flow path but without coupled neutronics, 2) forced circulation model with constant external pressure drop across the heated channels but without coupled neutronics, 3) coupled system including neutronics with

  17. An investigation of natural circulation decay heat removal from an SP-100 reactor system for a lunar outpost

    NASA Astrophysics Data System (ADS)

    El-Genk, Mohamed S.; Xue, Huimin

    1992-01-01

    A transient thermal-hydraulic model of the decay heat removal from a 550 kWe SP-100 power system for a lunar outpost has been developed and used to assess the coolability of the system by natural circulation after reactor shutdown. Results show that natural circulation of lithium coolant is sufficient to ensure coolability of the reactor core after shutdown. Further improvement of the decay heat removal capability of the system could be achieved by increasing the dimensions of the decay heat exchanger duct. A radiator area of 10-15 m2 would be sufficient to maintain the reactor core safely coolable by natural circulation after shutdown. Increasing the area of the decay heat rejection radiator or the diameter of the heat pipes in the guard vessel wall insignificantly affects the decay heat removal capability of the system.

  18. Study of turbulent natural-circulation flow and low-Prandtl-number forced-convection flow. [LMFBR

    SciTech Connect

    Chung, K.S.; Thompson, D.H.

    1980-01-01

    Calculational methods and results are discussed for the coupled energy and momentum equations of turbulent natural circulation flow and low Prandtl number forced convection flow. The objective of this paper is to develop a calculational method for the study of the thermal-hydraulic behavior of coolant flowing in a liquid metal fast breeder reactor channel under natural circulation conditions. The two-equation turbulence model is used to evaluate the turbulent momentum transport property. Because the analogy between momentum transfer and heat transfer does not generally hold for low Prandtl number fluid and natural circulation flow conditions, the turbulent thermal conductivity is calculated independently using equations similar to the two-equation turbulence model. The numerical technique used in the calculation is the finite element method.

  19. The low-power low-pressure flow resonance in a natural circulation cooled boiling water reactor

    SciTech Connect

    Hagen, T.H.J.J. van der; Stekelenburg, A.J.C.

    1995-09-01

    The last few years the possibility of flow resonances during the start-up phase of natural circulation cooled BWRs has been put forward by several authors. The present paper reports on actual oscillations observed at the Dodewaard reactor, the world`s only operating BWR cooled by natural circulation. In addition, results of a parameter study performed by means of a simple theoretical model are presented. The influence of relevant parameters on the resonance characteristics, being the decay ratio and the resonance frequency, is investigated and explained.

  20. Thermally induced flow oscillation in vertical two-phase natural circulation loop

    SciTech Connect

    Lee, Sang Yong; Ishii, Mamoru

    1988-01-01

    In order to study the two-phase natural circulation during a small break loss of coolant accident in LWR, simulation experiments have been performed using Freon-113 boiling and condensation loop. In quasi-steady state, the flow became relatively stabilized and certain regular patterns of flow oscillations were detected with ranges of periods in 8-/approximately/35 seconds and 2.5-/approximately/4 minutes. In order to find out the nature of these oscillations, one-dimensional field equations for the single-phase (liquid) and two-phase region were set up, and these field equations were integrated along the loop. The homogeneous flow model was used for the two-phase region. Then the characteristic equation was derived using perturbation method. Thermal non-equilibrium and compressibility of each phase were not considered in the present analysis. The characteristic equation derived can be used to obtain the stability criteria. A simplified approach showed that the short-period oscillation were the manometer oscillation. The longer period oscillations were the density wave oscillation which had the period of oscillations close to the residence time of a fluid around the loop.

  1. Interleukin (IL)-18 Binding Protein Deficiency Disrupts Natural Killer Cell Maturation and Diminishes Circulating IL-18.

    PubMed

    Harms, Robert Z; Creer, Austin J; Lorenzo-Arteaga, Kristina M; Ostlund, Katie R; Sarvetnick, Nora E

    2017-01-01

    The cytokine interleukin (IL)-18 is a crucial amplifier of natural killer (NK) cell function. IL-18 signaling is regulated by the inhibitory effects of IL-18 binding protein (IL-18BP). Using mice deficient in IL-18BP (IL-18BPKO), we investigated the impact of mismanaged IL-18 signaling on NK cells. We found an overall reduced abundance of splenic NK cells in the absence of IL-18BP. Closer examination of NK cell subsets in spleen and bone marrow using CD27 and CD11b expression revealed that immature NK cells were increased in abundance, while the mature population of NK cells was reduced. Also, NK cells were polarized to greater production of TNF-α, while dedicated IFN-γ producers were reduced. A novel subset of IL-18 receptor α(-) NK cells contributed to the expansion of immature NK cells in IL-18BPKO mice. Splenocytes cultured with IL-18 resulted in alterations similar to those observed in IL-18BP deficiency. NK cell changes were associated with significantly reduced levels of circulating plasma IL-18. However, IL-18BPKO mice exhibited normal weight gain and responded to LPS challenge with a >10-fold increase in IFN-γ compared to wild type. Finally, we identified that the source of splenic IL-18BP was among dendritic cells/macrophage localized to the T cell-rich regions of the spleen. Our results demonstrate that IL-18BP is required for normal NK cell abundance and function and also contributes to maintaining steady-state levels of circulating IL-18. Thus, IL-18BP appears to have functions suggestive of a carrier protein, not just an inhibitor.

  2. Interleukin (IL)-18 Binding Protein Deficiency Disrupts Natural Killer Cell Maturation and Diminishes Circulating IL-18

    PubMed Central

    Harms, Robert Z.; Creer, Austin J.; Lorenzo-Arteaga, Kristina M.; Ostlund, Katie R.; Sarvetnick, Nora E.

    2017-01-01

    The cytokine interleukin (IL)-18 is a crucial amplifier of natural killer (NK) cell function. IL-18 signaling is regulated by the inhibitory effects of IL-18 binding protein (IL-18BP). Using mice deficient in IL-18BP (IL-18BPKO), we investigated the impact of mismanaged IL-18 signaling on NK cells. We found an overall reduced abundance of splenic NK cells in the absence of IL-18BP. Closer examination of NK cell subsets in spleen and bone marrow using CD27 and CD11b expression revealed that immature NK cells were increased in abundance, while the mature population of NK cells was reduced. Also, NK cells were polarized to greater production of TNF-α, while dedicated IFN-γ producers were reduced. A novel subset of IL-18 receptor α− NK cells contributed to the expansion of immature NK cells in IL-18BPKO mice. Splenocytes cultured with IL-18 resulted in alterations similar to those observed in IL-18BP deficiency. NK cell changes were associated with significantly reduced levels of circulating plasma IL-18. However, IL-18BPKO mice exhibited normal weight gain and responded to LPS challenge with a >10-fold increase in IFN-γ compared to wild type. Finally, we identified that the source of splenic IL-18BP was among dendritic cells/macrophage localized to the T cell-rich regions of the spleen. Our results demonstrate that IL-18BP is required for normal NK cell abundance and function and also contributes to maintaining steady-state levels of circulating IL-18. Thus, IL-18BP appears to have functions suggestive of a carrier protein, not just an inhibitor. PMID:28900426

  3. Raynaud's phenomenon.

    PubMed

    O'connor, C M

    2001-09-01

    Many persons are affected by the phenomenon known as Raynaud's. Raynaud's is classified in 2 ways-as Raynaud's disease or Raynaud's syndrome. Classification is based on the presence of associated conditions. Raynaud's is characterized by vasospasm-induced color changes of the fingers, toes, and ears. The fingers are most commonly affected. Studies involving cause, diagnosis, and treatment have been instituted with varied results. Diagnosis is primarily based on clinical symptoms involving digital color changes. Treatment is aimed at prevention of attacks and includes medication, stress reduction, and avoidance of vasoconstricting agents. Whether the phenomenon will develop into a more serious condition with which Raynaud's is associated is important. This article describes the etiology, pathophysiology, diagnosis, treatment, and nursing implications with regard to Raynaud's.

  4. Calculation of the Phenix end-of-life test in natural circulation with the CATHARE code

    SciTech Connect

    Maas, L.; Cocheme, F.

    2012-07-01

    The Inst. of Radiological Protection and Nuclear Safety (IRSN) acts as technical support to French public authorities. As such, IRSN is in charge of safety assessment of operating and under construction reactors, as well as future projects. In this framework, one current objective of IRSN is to evaluate the ability and accuracy of numerical tools to foresee consequences of accidents. One of the advantages pointed up for fast reactors cooled by heavy liquid metal is the possibility of decay heat removal based on natural convection. The promotion of this passive cooling mode in future safety demonstrations will involve the use of adapted and validated numerical codes. After the final shutdown of the Phenix sodium cooled fast reactor in 2009, a set of tests covering different areas was conducted for code validation, including a natural circulation test in the primary circuit. Experimental data were issued by CEA to organize a benchmark exercise in the frame of an IAEA Coordinated Research Project (CRP), with the objective to assess the system-codes capability in simulating the thermal-hydraulics behavior of sodium cooled fast reactors in such accidental conditions. IRSN participated to this benchmark with the CATHARE code. This code, co-developed by CEA, EDF, AREVA and IRSN and widely used for PWR safety studies, was recently extended for sodium applications. This paper presents the CATHARE modeling of the Phenix primary circuit and the results obtained. A relatively good agreement was found with available measurements considering the experimental uncertainties. This work stressed the local aspects of phenomena occurring during the natural convection establishment and the limits of a 0D/1D approach. (authors)

  5. Steam condensation and liquid hold-up in steam generator U-tubes during oscillatory natural circulation

    SciTech Connect

    De Santi, G.F.; Mayinger, F.

    1990-01-01

    In many accident scenarios, natural circulation is an important heat transport mechanism for long-term cooling of light water reactors. In the event of a small pipe break, with subsequent loss of primary cooling fluid loss-of-coolant accident (LOCA), or under abnormal operating conditions, early tripping of the main coolant pumps can be actuated. Primary fluid flow will then progress from forced to natural convection. Understanding of the flow regimes and heat-removal mechanisms in the steam generators during the entire transient is of primary importance to safety analysis. Flow oscillations during two-phase natural circulation experiments for pressurized water reactors (PWRs) with inverted U-tube steam generators occur at high pressure and at a primary inventory range between two-phase circulation and reflex heat removal. This paper deals with the oscillatory flow behavior that was observed in the LOBI-MOD2 facility during the transition period between two-phase natural circulation and reflex condensation.

  6. Thermohydraulic model experiments and calculations on the transition from forced to natural circulation for pool-type fast reactors

    SciTech Connect

    Hoffmann, H.; Marten, K.; Weinberg, D.; Kamide, H.

    1990-01-01

    After a reactor scram, the decay heat removal (DHR) is of decisive importance for the safety of the plant. A fully passive DHR system based on natural circulation alone is independent of any power source. The DHE system consists of immersion coolers (ICs) installed in the hot plenum and connected to air coolers, each via intermediate circuits. During the postscram phase, the decay heat is to be removed by natural circulation from the core into the hot plenum and via the ICs and intermediate loops to the air coolers. The function of this DHR system is investigated and demonstrated in model tests with a geometry similar to the reactor, though on a different scale RAMONA is such a three-dimensional model set up on a 1:20 scale. It is operated with water. The steady-state tests for natural-circulation DHR operations have been conducted over a wide range of operational and geometric parameters. To study the transition from nominal to DHR conditions, experiments were defined to investigate the onset of natural circulation in the postscram phase (transient tests). The experiments were analyzed using the one-dimensional LEDHER code. LEDHER is a network analysis code for the long-term DHR of a fast reactor developed at Power Reactor and Nuclear Fuel Development Corporation in Japan. The results of the experiments and conclusions are summarized.

  7. [Impact of effect of natural disasters on the circulation of causative agents of parasitic diseases].

    PubMed

    Vaserin, Iu I; Khromenkova, E P; Dimidova, L L; Tverdokhlebova, T I; Nagornyĭ, S A; Prokopova, L V; Dumbadze, O S; Murashov, N E; Butaev, T M; Agirov, A Kh; Osmolovskiĭ, S V; Papatsenko, L B; Soldatova, M V

    2005-01-01

    The southern region is marked by a high incidence of parasitic diseases and a significant contamination of environmental objects with the eggs and cysts of their pathogens. Background examinations revealed the greatest soil contamination with helminthic eggs in the Temryuksky District of the Krasnodar Territory and in the towns of Vladikavkaz and Digora of the Republic of North Ossetia (Alania). The least contamination was found in Rostov-on-Don and the towns of the south-western area of the Krasnodar Territory. The eggs of Toxocara and astamination. There is an increase in the proportion of soil positive tests from 26.6 to 50.0, with the high (up to 82.0-100.0%) viability of eggs and a rise in the intensive index of their content per kg of soil (from 2.7 to 4.7-11.0). Toxocara eggs were mainly detected. The established high proportion of seropositive persons (10.7-18.0%) among the local population is an additional verification of the wide circulation of Toxocara eggs in nature. By the helminthic egg contamination index, the soils of localities of the south of Russia are qualified as those of moderate epidemic hazard. The floods accompanied by the increased helminthological contamination of the upper soil layer may lead to a higher human risk for contamination with helminthic diseases.

  8. Results of two-phase natural circulation in hot-leg U-bend simulation experiments

    SciTech Connect

    Ishii, M.; Lee, S.Y.; Abou El-Seoud, S.

    1987-01-01

    In order to study the two-phase natural circulation and flow termination during a small break loss of coolant accident in LWR, simulation experiments have been performed using two different thermal-hydraulic loops. The main focus of the experiment was the two-phase flow behavior in the hot-leg U-bend typical of BandW LWR systems. The first group of experiments was carried out in the nitrogen gas-water adiabatic simulation loop and the second in the Freon 113 boiling and condensation loop. Both of the loops have been designed as a flow visualization facility and built according to the two-phase flow scaling criteria developed under this program. The nitrogen gas-water system has been used to isolate key hydrodynamic phenomena such as the phase distribution, relative velocity between phases, two-phase flow regimes and flow termination mechanisms, whereas the Freon loop has been used to study the effect of fluid properties, phase changes and coupling between hydrodynamic and heat transfer phenomena. Significantly different behaviors have been observed due to the non-equilibrium phase change phenomena such as the flashing and condensation in the Freon loop. The phenomena created much more unstable hydrodynamic conditions which lead to cyclic or oscillatory flow behaviors.

  9. Chaotic Phenomena and Analysis of Natural Circulation Flow Instability under Rolling Motion Condition

    NASA Astrophysics Data System (ADS)

    Tan, S. C.; Gao, P. Z.

    2010-03-01

    Experimental study on natural circulation flow instability under rolling motion is carried out and the results show that the complex flow oscillations are formed due to the overlapped effect of the rolling motion (trough instability) and density wave oscillation. The system becomes more instable because of the occurrence of complex flow oscillations. Complex flow oscillations only occur in the case of high subcooling and may be divided into two types: regular and irregular complex flow oscillations. Under the same thermo hydraulic conditions, the marginal stability boundary (MSB) of regular complex oscillations is similar to that of density wave oscillation without rolling motion. And the influences of rolling amplitude and rolling period on its MSB are slight. Chaotic characteristics are found in irregular complex oscillation flow under rolling motion condition. Based on the experimental data and G-P method, correlation dimension and Kolmogorov entropy are gotten with time series analysis. The results show that complex oscillation has fractal dimension and positive Kolmogorov entropy and is typical chaotic time series.

  10. Experiments in a single-phase natural circulation mini-loop

    SciTech Connect

    Misale, M.; Garibaldi, P.; Passos, J.C.; de Bitencourt, G. Ghisi

    2007-08-15

    This study reports an experimental investigation related to a rectangular single-phase natural circulation mini-loop, which consists of two horizontal copper tubes (heat transfer sections) and two vertical tubes (legs) made of copper, connected by means of four glass 90 bends. The loop inner diameter is 4 mm. The lower heating section consists of an electrical heating wire made of nicromel on the outside of the copper tube; the upper cooling system consists of a coaxial cylindrical heat exchanger with a water-glycol mixture, set at controlled temperature and flowing through the annulus. The loop has an imposed heat flux in the lower heating section and an imposed temperature in the cooler. The mini-loop was placed onto a table which can assume different inclinations. The parameters investigated during the experiments were: power transferred to the fluid and inclination of the loop. The preliminary results show a stable behaviour with a steady temperature difference across the heat sinks. It has been confirmed that the fluid velocity is very small (order of millimetres per second). (author)

  11. Preliminary numerical studies of an experimental facility for heat removal in natural circulation

    NASA Astrophysics Data System (ADS)

    Bertani, C.; De Salve, M.; Caramello, M.; Falcone, N.; Bersano, A.; Panella, B.

    2017-01-01

    In recent years particular attention has been dedicated to passive safety systems for heat removal in nuclear power plants. Passive safety systems can achieve a high level of safety, as they carry out their mission relying solely on physical principles like natural circulation, without any need of operators or energy sources. To qualify these systems and components experimental activities are necessary to study and to understand the governing physical phenomena. The present paper shows the design of an experimental facility to be installed in the laboratories of the Energy Department of Politecnico di Torino. The facility is inspired by the decay heat removal system for ALFRED reactor and comprehends a heated bayonet tube and a heat sink for the heat removal (a heat exchanger inside a pool). The thermal power is in the order of 1 kW. A RELAP5-3D model of the facility has been developed and sensitivity analyses were performed to highlight the geometry of the heat exchanger, the final heat sink, and the mass of water inside the loop. The results of this phase serve to understand the physical limits of the facility, to demonstrate a preliminary feasibility and to optimize the geometry for the desired operating conditions.

  12. Vacuum phenomenon.

    PubMed

    Yanagawa, Youichi; Ohsaka, Hiromichi; Jitsuiki, Kei; Yoshizawa, Toshihiko; Takeuchi, Ikuto; Omori, Kazuhiko; Oode, Yasumasa; Ishikawa, Kouhei

    2016-08-01

    This article describes the theory of the formation of the vacuum phenomenon (VP), the detection of the VP, the different medical causes, the different locations of the presentation of the VP, and the differential diagnoses. In the human body, the cavitation effect is recognized on radiological studies; it is called the VP. The mechanism responsible for the formation of the VP is as follows: if an enclosed tissue space is allowed to expand as a rebound phenomenon after an external impact, the volume within the enclosed space will increase. In the setting of expanding volume, the pressure within the space will decrease. The solubility of the gas in the enclosed space will decrease as the pressure of the space decreases. Decreased solubility allows a gas to leave a solution. Clinically, the pathologies associated with the VP have been reported to mainly include the normal joint motion, degeneration of the intervertebral discs or joints, and trauma. The frequent use of CT for trauma patients and the high spatial resolution of CT images might produce the greatest number of chances to detect the VP in trauma patients. The VP is observed at locations that experience a traumatic impact; thus, an analysis of the VP may be useful for elucidating the mechanism of an injury. When the VP is located in the abdomen, it is important to include perforation of the digestive tract in the differential diagnosis. The presence of the VP in trauma patients does not itself influence the final outcome.

  13. A Mass Circulation View of the Low Frequency Nature of the Stratospheric Northern Annular Mode

    NASA Astrophysics Data System (ADS)

    Yu, Y.; Cai, M.

    2016-12-01

    We consider three indices to measure polar stratospheric mass and stratospheric meridional mass circulation variability: anomalies of (i) total mass in the polar stratospheric cap (60-90°N, above the isentropic surface 400 K, PSM), (ii) total adiabatic mass transport across 60°N into the polar stratosphere cap (AMT), (iii) and total diabatic mass transport across 400 K into the polar stratosphere (DMT). It is confirmed that the negative stratospheric Northern Annular Mode (NAM) and normalized PSM indices have a nearly indistinguishable temporal evolution and both indices have the same red-noise-like spectrum with the de-correlation timescale of 4 weeks. In this sense, these two indices are synonymous with each other. This enables us to examine the low-frequency nature of the PSM (or NAM) index in the framework of the mass conservation, namely, dPSM/dt=AMT+DMT . Results indicate that the DMT index tends to be negatively correlated with the PSM index and also has a red-noise-like spectrum with the de-correlation timescale of 3-4 weeks. The AMT index, however, has a large positive correlation with the tendency of the PSM rather than the PSM itself. The temporal variability of the AMT has otherwise white-noise-like spectrum except with a pronounced peak at the 2-week timescale. Therefore, the conservation equation of the PSM behaves like a linear stochastic differential equation with the DMT serving as the thermal damping term and the AMT as the high-frequency white noise source term. It follows that the low-frequency nature of the stratospheric NAM (or PSM) index can be viewed as the red-noise response to a white noise in a fluctuation-dissipation system.

  14. [Raynaud's phenomenon].

    PubMed

    Sprynger, M

    2004-06-01

    Raynaud's phenomenon (RP) is a common vascular disorder characterized by a recurrent transient vasospasm of the fingers and toes on exposure to cold or with emotional stress. Clinical criteria are used to distinguish patients with primary or idiopathic RP (formely Raynaud's disease) from those with secondary RP (formely Raynaud's syndrome). They include history, general physical examination, capillaroscopy, test for antinuclear antibody and erythrocyte sedimentation rate. More specific exams may be needed in selective cases. Excluding RP of occupational origin, the most common cause of secondary RP is a connective tissue disease (particularly scleroderma). RP may precede other clinical symptoms by several years, but most patients with RP will not progress to systemic disease. Nevertheless, primary RP may cause significant disability. We review the pathophysiology and clinical criteria of the disorder. Unfortunately, management of PR is still empirical and largely supportive.

  15. [Raynaud's phenomenon].

    PubMed

    Tomčík, Michal

    2016-01-01

    Raynaud's phenomenon (RP) is a very common sign which can usually be seen across all medical specialties. It is characterized by episodic color changes of acral parts of the body (palor, cyanosis, rubor) lasting from a few minutes to hours, which are usually triggered by cold temperature and/or stress. The primary RP occurs alone, without concomitant diseases, is usually benign and has favorable prognosis. Secondary RP occurs in a variety of diseases with a very variable progression and prognosis, mostly unfavorable one due to the development of ischemic tissue necrosis and gangrene. This work provides a comprehensive overview of the history, current knowledge about the epidemiology and pathogenesis and the recommended evaluation and treatment of RP.

  16. Climatology and natural variability of the global hydrologic cycle in the GLA atmospheric general circulation model

    NASA Technical Reports Server (NTRS)

    Lau, K.-M.; Mehta, V. M.; Sud, Y. C.; Walker, G. K.

    1994-01-01

    Time average climatology and low-frequency variabilities of the global hydrologic cycle (GHC) in the Goddard Laboratory for Atmospheres (GLA) general circulation model (GCM) were investigated in the present work. A 730-day experiment was conducted with the GLA GCM forced by insolation, sea surface temperature, and ice-snow undergoing climatological annual cycles. Ifluences of interactive soil moisture on time average climatology and natural variability of the GHC were also investigated by conducting 365-day experiments with and without interactive soil moisture. Insolation, sea surface temperature, and ice-snow were fixed at their July levels in the latter two experiments. Results show that the model's time average hydrologic cycle variables for July in all three experiments agree reasonably well with observations. Except in the case of precipitable water, the zonal average climates of the annual cycle experiment and the two perpetual July experiments are alike, i.e., their differences are within limits of the natural variability of the model's climate. Statistics of various components of the GHC, i.e., water vapor, evaporation, and precipitation, are significantly affected by the presence of interactive soil moisture. A long-term trend is found in the principal empirical modes of variability of ground wetness, evaporation, and sensible heat. Dominant modes of variability of these quantities over land are physically consistent with one another and with land surface energy balance requirements. The dominant mode of precipitation variability is found to be closely related to organized convection over the tropical western Pacific Ocean. The precipitation variability has timescales in the range of 2 to 3 months and can be identified with the stationary component of the Madden-Julian Oscillation. The precipitation mode is not sensitive to the presence of interactive soil moisture but is closely linked to both the rotational and divergent components of atmospheric

  17. Climatology and natural variability of the global hydrologic cycle in the GLA atmospheric general circulation model

    NASA Technical Reports Server (NTRS)

    Lau, K.-M.; Mehta, V. M.; Sud, Y. C.; Walker, G. K.

    1994-01-01

    Time average climatology and low-frequency variabilities of the global hydrologic cycle (GHC) in the Goddard Laboratory for Atmospheres (GLA) general circulation model (GCM) were investigated in the present work. A 730-day experiment was conducted with the GLA GCM forced by insolation, sea surface temperature, and ice-snow undergoing climatological annual cycles. Ifluences of interactive soil moisture on time average climatology and natural variability of the GHC were also investigated by conducting 365-day experiments with and without interactive soil moisture. Insolation, sea surface temperature, and ice-snow were fixed at their July levels in the latter two experiments. Results show that the model's time average hydrologic cycle variables for July in all three experiments agree reasonably well with observations. Except in the case of precipitable water, the zonal average climates of the annual cycle experiment and the two perpetual July experiments are alike, i.e., their differences are within limits of the natural variability of the model's climate. Statistics of various components of the GHC, i.e., water vapor, evaporation, and precipitation, are significantly affected by the presence of interactive soil moisture. A long-term trend is found in the principal empirical modes of variability of ground wetness, evaporation, and sensible heat. Dominant modes of variability of these quantities over land are physically consistent with one another and with land surface energy balance requirements. The dominant mode of precipitation variability is found to be closely related to organized convection over the tropical western Pacific Ocean. The precipitation variability has timescales in the range of 2 to 3 months and can be identified with the stationary component of the Madden-Julian Oscillation. The precipitation mode is not sensitive to the presence of interactive soil moisture but is closely linked to both the rotational and divergent components of atmospheric

  18. Thermohydraulic model experiments on the transition from forced to natural circulation for pool-type fast reactors

    SciTech Connect

    Hoffmann, H.; Marten, K.; Weinberg, D. )

    1992-09-01

    In this paper, thermohydraulic studies on the transition from forced to natural convection are carried out using the 1:20 scale RAMONA three-dimensional reactor model with water as the simulant fluid. In the investigations, a scram from 40% load operation of a fast reactor is simulated. The core mass flows and the core as well as the hot plenum temperatures are measured as a function of time for various core power levels, coastdown curves of the primary- and secondary-side pumps, and for various delay times for the start of the immersion coolers after a scram. These parameters influence the onset of the natural circulation in the reactor tank. The main result is that the longer the intermediate heat exchanger coolability is ensured and the later the immersion coolers start to operate, the higher is the natural-circulation flow and, hence, the lower are the core temperatures.

  19. Evaluation of circulating levels and renal clearance of natural amino acids in patients with Cushing's disease.

    PubMed

    Faggiano, A; Pivonello, R; Melis, D; Alfieri, R; Filippella, M; Spagnuolo, G; Salvatore, F; Lombardi, G; Colao, A

    2002-02-01

    Although the hypercortisolism-induced impairment of protein homeostasis is object of several studies, a detailed evaluation of the complete amino acid profile of patients with Cushing's syndrome (CS) has never been performed. The aim of the current open transversal controlled study was to evaluate serum and urinary concentrations as well as renal clearance of the complete series of natural amino acids and their relationship with glucose tolerance in patients with Cushing's disease (CD). Twenty patients with CD (10 active and 10 cured) and 20 sex- and age-matched healthy controls entered the study. Measurement of serum and urinary levels of the complete series of natural amino acids was performed in all patients analyzed by cationic exchange high performance liquid cromatography (HPLC) after 2 weeks of a standardized protein intake regimen. The renal clearance (renal excretion rate) of each amino acid was calculated on the basis of the serum and urinary concentrations of creatinine and the specific amino acid. Fasting glucose and insulin levels, glucose and insulin response to standard glucose load, insulinogenic and homeostasis model insulin resistance (Homa-R) indexes were also evaluated and correlated to the circulating levels and renal clearances of each amino acid. Significantly higher serum (p<0.01) and urinary (p<0.05) levels of alanine and cystine, lower serum and higher urinary levels of leucine, isoleucine and valine (p<0.05) and higher renal excretion rates of leucine, isoleucine and valine (p<0.01) were found in patients with active CD than in patients cured from the disease and in controls. No difference was found between cured patients and controls. Creatinine clearance was similar in active and cured patients and in controls. In patients with active CD, urinary cortisol levels were significantly correlated to urinary cystine levels (r=0.85; p<0.01) and renal excretion rate of leucine (r=-0.76; p<0.05), isoleucine (r=-0.76; p<0.05) and valine (r=-0

  20. Indomethacin Inhibits Circulating PGE2 and Reverses Postexercise Suppression of Natural Killer Cell Activity

    DTIC Science & Technology

    1999-01-01

    after the oral administration of a placebo, the PG inhibitor indomethacin (75 mg/day for 5 days), or naltrexone (reported elsewhere). Circulating...which blocks PGE2 biosynthe- sis via inhibition of cyclooxygenase activity (57). Maxi- mal suppression of PG production occurs with doses between 50...and 150 mg (1). In addition to the indepen- dent effects of PGE2 on NKCA, low circulating levels of PGE2 can synergize with endogenous glucocorticoids

  1. The natural history of fetal cells in postpartum murine maternal lung and bone marrow: a two-stage phenomenon.

    PubMed

    Pritchard, Stephanie; Peter, Inga; Johnson, Kirby L; Bianchi, Diana W

    2012-01-01

    During pregnancy, fetal cells cross into the maternal organs where they reside postpartum. Evidence from multiple laboratories suggests that these microchimeric fetal cells contribute to maternal tissue repair after injury. In mouse models, most injury experiments are performed during pregnancy; however, in a clinical setting most injuries or diseases occur postpartum. Therefore, experiments using animal models should be designed to address questions in the time period following delivery. In order to provide a baseline for such experiments, we analyzed the natural history of fetal cells in the postpartum maternal organs. Female C57BL/6J mice were mated to males homozygous for the enhanced green fluorescent protein gene. Fetal cells in the maternal lungs and bone marrow were identified by their green fluorescence using in a high-speed flow cytometer and their counts were compared between the lung and bone marrow. Spearman correlation analysis was used to identify relationships between the duration of time postpartum and the cell counts and ratio of live and dead cells. Our results show that fetal cells persist in these organs until at least three months postpartum in healthy female mice. We show a two-stage decline, with an initial two and a half-week rapid clearance followed by a trend of gradual decrease. Additionally, an increase in the ratio of live to dead cells within the lung over time suggests that these cells may replicate in vivo. The results presented here will inform the design of future experiments and may have implications for women's health.

  2. Pulsational characteristics of the natural-circulation loop of a large-scale model of a light-boiling boiling-water reactor

    SciTech Connect

    Babykin, A.S.; Balunov, B.F.; Chernykh, N.G.; Smirnov, E.L.; Tisheninova, V.I.; Zhiuitskaya, T.S.

    1985-10-01

    The results of an experimental study of a natural-circulation (NC) loop, whose geometrical and hydraulic characteristics are presented are described. The range of state parameters encompassed in the experiments is also indicated. The authors used a large-scale model of a low-boiling-water reactor, with natural heights and reduced stages of separate elements of the NC loop. The study confirmed that under the conditions the pulsations in the flow rate of the coolant occurs only in the transitional zone from natural circulation of the singlephase medium to natural circulation of the two-phase coolant.

  3. Design of Complex Systems to Achieve Passive Safety: Natural Circulation Cooling of Liquid Salt Pebble Bed Reactors

    NASA Astrophysics Data System (ADS)

    Scarlat, Raluca Olga

    This dissertation treats system design, modeling of transient system response, and characterization of individual phenomena and demonstrates a framework for integration of these three activities early in the design process of a complex engineered system. A system analysis framework for prioritization of experiments, modeling, and development of detailed design is proposed. Two fundamental topics in thermal-hydraulics are discussed, which illustrate the integration of modeling and experimentation with nuclear reactor design and safety analysis: thermal-hydraulic modeling of heat generating pebble bed cores, and scaled experiments for natural circulation heat removal with Boussinesq liquids. The case studies used in this dissertation are derived from the design and safety analysis of a pebble bed fluoride salt cooled high temperature nuclear reactor (PB-FHR), currently under development in the United States at the university and national laboratories level. In the context of the phenomena identification and ranking table (PIRT) methodology, new tools and approaches are proposed and demonstrated here, which are specifically relevant to technology in the early stages of development, and to analysis of passive safety features. A system decomposition approach is proposed. Definition of system functional requirements complements identification and compilation of the current knowledge base for the behavior of the system. Two new graphical tools are developed for ranking of phenomena importance: a phenomena ranking map, and a phenomena identification and ranking matrix (PIRM). The functional requirements established through this methodology were used for the design and optimization of the reactor core, and for the transient analysis and design of the passive natural circulation driven decay heat removal system for the PB-FHR. A numerical modeling approach for heat-generating porous media, with multi-dimensional fluid flow is presented. The application of this modeling

  4. Deficiencies of Circulating Mucosal-associated Invariant T Cells and Natural Killer T Cells in Patients with Multiple Trauma.

    PubMed

    Jo, Young Goun; Choi, Hyun Jung; Kim, Jung Chul; Cho, Young Nan; Kang, Jeong Hwa; Jin, Hye Mi; Kee, Seung Jung; Park, Yong Wook

    2017-05-01

    Mucosal-associated invariant T (MAIT) cells and natural killer T (NKT) cells are known to play important roles in autoimmunity, infectious diseases and cancers. However, little is known about the roles of these invariant T cells in multiple trauma. The purposes of this study were to examine MAIT and NKT cell levels in patients with multiple trauma and to investigate potential relationships between these cell levels and clinical parameters. The study cohort was composed of 14 patients with multiple trauma and 22 non-injured healthy controls (HCs). Circulating MAIT and NKT cell levels in the peripheral blood were measured by flow cytometry. The severity of injury was categorised according to the scoring systems, such as Acute Physiology and Chronic Health Evaluation (APACHE) II score, Simplified Acute Physiology Score (SAPS) II, and Injury Severity Score (ISS). Circulating MAIT and NKT cell numbers were significantly lower in multiple trauma patients than in HCs. Linear regression analysis showed that circulating MAIT cell numbers were significantly correlated with age, APACHE II, SAPS II, ISS category, hemoglobin, and platelet count. NKT cell numbers in the peripheral blood were found to be significantly correlated with APACHE II, SAPS II, and ISS category. This study shows numerical deficiencies of circulating MAIT cells and NKT cells in multiple trauma. In addition, these invariant T cell deficiencies were found to be associated with disease severity. These findings provide important information for predicting the prognosis of multiple trauma. © 2017 The Korean Academy of Medical Sciences.

  5. Experimental investigation on the flow instability behavior of a multi-channel boiling natural circulation loop at low-pressures

    SciTech Connect

    Jain, Vikas; Nayak, A.K.; Vijayan, P.K.; Saha, D.; Sinha, R.K.

    2010-09-15

    Natural circulation as a mode of heat removal is being considered as a prominent passive feature in the innovative nuclear reactor designs, particularly in boiling-water-reactors, due to its simplicity and economy. However, boiling natural circulation system poses many challenges to designer due to occurrence of various kinds of instabilities such as excursive instability, density wave oscillations, flow pattern transition instability, geysering and metastable states in parallel channels. This problem assumes greater significance particularly at low-pressures i.e. during startup, where there is great difference in the properties of two phases. In light of this, a parallel channel loop has been designed and installed that has a geometrical resemblance to the pressure-tube-type boiling-water-reactor, to investigate into the behavior of boiling natural circulation. The loop comprises of four identical parallel channels connected between two common plenums i.e. steam drum and header. The recirculation path is provided by a single downcomer connected between steam drum and header. Experiments have been conducted over a wide range of power and pressures (1-10 bar). Two distinct unstable zones are observed with respect to power i.e. corresponding to low power (Type-I) and high power (Type-II) with a stable zone at intermediate powers. The nature of oscillations in terms of their amplitude and frequency and their evolution for Type-I and Type-II instabilities are studied with respect to the effect of heater power and pressure. This paper discusses the evolution of unstable and stable behavior along with the nature of flow oscillation in the channels and the effect of pressure on it. (author)

  6. An experimental investigation of single-phase natural circulation behavior in a rectangular loop with Al{sub 2}O{sub 3} nanofluids

    SciTech Connect

    Nayak, A.K.; Gartia, M.R.; Vijayan, P.K.

    2008-10-15

    In this paper, the natural circulation behavior in a rectangular loop was investigated experimentally with water and different concentration of Al{sub 2}O{sub 3} nanofluids (0.3-2% by wt. and particle size 40-80 nm). It was demonstrated that, not only the flow instabilities are suppressed but also the natural circulation flow rates are enhanced with nanofluids. The enhancement in natural circulation flow rate and suppression of instabilities were found to be dependent on the concentration of nanoparticles in water. (author)

  7. Antimicrobial activity of various immunomodulators: independence from normal levels of circulating monocytes and natural killer cells. Technical report

    SciTech Connect

    Morahan, P.S.; Dempsey, W.L.; Volkman, A.; Connor, J.

    1986-01-01

    The effects of /sup 89/Sr treatment on the natural host resistance of CD-1 mice and the enhancement of resistance by immunomodulators to infection with Listeria monocytogenes or herpes simplex virus type 2 (HSV-2) were determined. In the CD-1 mouse, single-dose treatment with /sup 89/Sr caused a profound decrease in the number of circulating monocytes (Mo), lymphocytes, and polymorphonuclear leukocytes (PMN) within 1 week. There was also marked functional impairment of the Mo inflammatory response, as well as markedly decreased spontaneous and activatable cytoxicity by splenic natural killer (NK) cells. Despite this profound cellular suppression, there was no significant change in natural resistance of CD-1 mice to L. monocytogenes of HSV-2 infection. Furthermore, prophylactic treatment of mice with the biologic immunomodulator Corynebacterium parvum or the synthetic immunomodulators maleic anhydride-divinyl ether or avridine in liposomes resulted in comparable enhancement of resistance in /sup 89/Sr-treated and normal mice. These data indicate that natural and immunomodulator-enhanced resistance of CD-1 mice to microbail infections do not depend on normal levels of Mo, PMN, or NK cells. The resistance enhancement may rely on activated tissue macrophages. In contrast to the early changes in circulating leukocytes, the residenet peritoneal cell populations were not markedly altered until after day 30. There then was a distinct decline in lymphocytes and a gradual decline in activated tissue macrophages.

  8. The Essential Role of Circulating Thyroglobulin in Maintaining Dominance of Natural Regulatory T Cell Function to Prevent Autoimmune Thyroiditis.

    PubMed

    Kong, Y M; Brown, N K; Morris, G P; Flynn, J C

    2015-09-01

    Several key findings from the late 1960s to mid-1970s regarding thyroid hormone metabolism and circulating thyroglobulin composition converged with studies pertaining to the role of T lymphocytes in autoimmune thyroiditis. These studies cemented the foundation for subsequent investigations into the existence and antigenic specificity of thymus-derived natural regulatory T cells (nTregs). These nTregs prevented the development of autoimmune thyroiditis, despite the ever-present genetic predisposition, autoantigen (thyroglobulin), and thyroglobulin-reactive T cells. Guided by the hypothalamus-pituitary-thyroid axis as a fixed set-point regulator in thyroid hormone metabolism, we used a murine model and compared at key junctures the capacity of circulating thyroglobulin level (raised by thyroid-stimulating hormone or exogenous thyroglobulin administration) to strengthen self-tolerance and resist autoimmune thyroiditis. The findings clearly demonstrated an essential role for raised circulating thyroglobulin levels in maintaining the dominance of nTreg function and inhibiting thyroid autoimmunity. Subsequent identification of thyroglobulin-specific nTregs as CD4(+)CD25(+)Foxp3(+) in the early 2000s enabled the examination of probable mechanisms of nTreg function. We observed that whenever nTreg function was perturbed by immunotherapeutic measures, opportunistic autoimmune disorders invariably surfaced. This review highlights the step-wise progression of applying insights from endocrinologic and immunologic studies to advance our understanding of the clonal balance between natural regulatory and autoreactive T cells. Moreover, we focus on how tilting the balance in favor of maintaining peripheral tolerance could be achieved. Thus, murine autoimmune thyroiditis has served as a unique model capable of closely simulating natural physiologic conditions.

  9. Circulating natural killer and gammadelta T cells decrease soon after infection of rhesus macaques with lymphocytic choriomeningitis virus.

    PubMed

    Rodas, Juan D; Cairo, Cristiana; Djavani, Mahmoud; Zapata, Juan Carlos; Ruckwardt, Tracy; Bryant, Joseph; Pauza, C David; Lukashevich, Igor S; Salvato, Maria S

    2009-07-01

    Rhesus macaques infected with the WE strain of lymphocytic choriomeningitis virus (LCMV-WE) serve as a model for human infection with Lassa fever virus. To identify the earliest events of acute infection, rhesus macaques were monitored immediately after lethal infection for changes in peripheral blood mononuclear cells (PBMCs). Changes in CD3, CD4, CD8 and CD20 subsets did not vary outside the normal fluctuations of these blood cell populations; however, natural killer (NK) and gammadelta T cells increased slightly on day 1 and then decreased significantly after two days. The NK subsets responsible for the decrease were primarily CD3-CD8+ or CD3-CD16+ and not the NKT (primarily CD3+CD56+) subset. Macaques infected with a non-virulent arenavirus, LCMV-Armstrong, showed a similar drop in circulating NK and gammadelta T cells, indicating that this is not a pathogenic event. V(3)9 T cells, representing the majority of circulating gammadelta T cells in rhesus macaques, displayed significant apoptosis when incubated with LCMV in cell culture; however, the low amount of cell death for virus-co-cultured NK cells was insufficient to account for the observed disappearance of this subset. Our observations in primates are similar to those seen in LCMV-infected mice, where decreased circulating NK cells were attributed to margination and cell death. Thus, the disappearance of these cells during acute hemorrhagic fever in rhesus macaques may be a cytokine-induced lymphopenia common to many virus infections.

  10. Natural variability of the climate as predicted by a simple ocean model with parameterized thermohaline circulation

    SciTech Connect

    Watts, R.G.; Li, S.

    1995-12-31

    Variability of the Earth`s climate can take place on many time scales as a result of internal features. This natural variability is important to humans since it affects such important human enterprises as agriculture, floods, droughts, etc. The authors investigate natural variability within a simple ocean model.

  11. [Circulating lipids in prolonged postoperative parenteral feeding: their changes depending on the nature of energy intake].

    PubMed

    Manelli, J C; Lallemand, J; Kiégel, P; Siccardi, F; Bimar, J

    1977-01-01

    Repeated estimations of circulating total lipids and various fractions were made during the postoperative period in patients receiving parenteral nutrition for more than ten days. The patients were paired in relation to the underlying pathology and divided into two group : the first receiving energy supplements in the form of carbohydrates alone, whilst the second received part of this supply in the form of lipid emulsions (Trive 1000). Total lipids and various plasma fractions, with the exception of free fatty acids, increased progressively during the postoperative period, regardless of the inital values and independently of the lipid content of the nutrition fluids given. There was no significant difference between those patients who received lipid emulsions and those who did not. Free fatty acids remained at levels slightly greater than normal in the group which did not receive lipids. They were significantly higher in the group given lipid emulsions, though it was not possible to precisely define their orgin.

  12. Lymphokine-activated killer cell phenomenon. Lysis of natural killer-resistant fresh solid tumor cells by interleukin 2-activated autologous human peripheral blood lymphocytes

    SciTech Connect

    Grimm, E.A.; Mazumder, A.; Zhang, H.Z.; Rosenberg, S.A.

    1982-06-01

    Activation in lectin-free interleukin 2 (IL-2) containing supernatants of peripheral blood mononuclear leukocytes (PBL) from cancer patients or normal individuals resulted in expression of cytotoxicity toward 20 of 21 natural killer (NK)-resistant fresh solid tumor cells tested. Fresh solid tumor cells were resistant to NK-mediated lysis in 10 autologous patients' PBL-tumor interactions, and from 17 normal individuals tested against 13 allogeneic fresh tumors. Culture of PBL in IL-2 for 2-3 d was required for the lymphokine activated killers (LAK) to be expressed, and lytic activity toward a variety of NK-resistant fresh and cultured tumor targets developed in parallel. Autologous IL-2 was functional in LAK activation, as well as interferon-depleted IL-2 preparations. Irradiation of responder PBL before culture in IL-2 prevented LAK development. Precursors of LAK were present in PBL depleted of adherent cells and in NK-void thoracic duct lymphocytes, suggesting that the precursor is neither a monocyte nor an NK cell. LAK effectors expressed the serologically defined T cell markers of OKT.3, Leu-1, and 4F2, but did not express the monocyte/NK marker OKM-1. Lysis of autologous fresh solid tumors by LAK from cancer patients' PBL was demonstrated in 85% of the patient-fresh tumor combinations. Our data present evidence that the LAK system is a phenomenon distinct from either NK or CTL systems that probably accounts for a large number of reported nonclassical cytotoxicities. The biological role of LAK cells is not yet known, although it is suggested that these cells may be functional in immune surveillance against human solid tumors.

  13. What Is Raynaud's Phenomenon?

    MedlinePlus

    ... Phenomenon PDF Version Size: 59 KB November 2014 What Is Raynaud’s Phenomenon? Fast Facts: An Easy-to- ... use tools that vibrate, such as a jackhammer. What Are the Symptoms of Raynaud’s Phenomenon? The body ...

  14. The global distribution of natural tritium in precipitation simulated with an Atmospheric General Circulation Model and comparison with observations

    NASA Astrophysics Data System (ADS)

    Cauquoin, A.; Jean-Baptiste, P.; Risi, C.; Fourré, É.; Stenni, B.; Landais, A.

    2015-10-01

    The description of the hydrological cycle in Atmospheric General Circulation Models (GCMs) can be validated using water isotopes as tracers. Many GCMs now simulate the movement of the stable isotopes of water, but here we present the first GCM simulations modelling the content of natural tritium in water. These simulations were obtained using a version of the LMDZ General Circulation Model enhanced by water isotopes diagnostics, LMDZ-iso. To avoid tritium generated by nuclear bomb testing, the simulations have been evaluated against a compilation of published tritium datasets dating from before 1950, or measured recently. LMDZ-iso correctly captures the observed tritium enrichment in precipitation as oceanic air moves inland (the so-called continental effect) and the observed north-south variations due to the latitudinal dependency of the cosmogenic tritium production rate. The seasonal variability, linked to the stratospheric intrusions of air masses with higher tritium content into the troposphere, is correctly reproduced for Antarctica with a maximum in winter. LMDZ-iso reproduces the spring maximum of tritium over Europe, but underestimates it and produces a peak in winter that is not apparent in the data. This implementation of tritium in a GCM promises to provide a better constraint on: (1) the intrusions and transport of air masses from the stratosphere, and (2) the dynamics of the modelled water cycle. The method complements the existing approach of using stable water isotopes.

  15. Evidence for the circulation of antimicrobial-resistant strains and genes in nature and especially between humans and animals.

    PubMed

    Wooldridge, M

    2012-04-01

    The concern over antibiotic-resistant bacteria producing human infections that are difficult to treat has led to a proliferation of studies in recent years investigating resistance in livestock, food products, the environment and people, as well as in the mechanisms of transfer of the genetic elements of resistance between bacteria, and the routes, or risk pathways, by which the spread of resistance might occur. The possibility of transfer of resistant genetic elements between bacteria in mixed populations adds many additional and complex potential routes of spread. There is now considerable evidence that transfer of antimicrobial resistance from food-producing animals to humans directly via the food chain is a likely route of spread. The application of animal wastes to farmland and subsequent leaching into watercourses has also been shown to lead to many potential, but less well-documented, pathways for spread. Often, however, where contamination of water sources, processed foods, and other environmental sites is concerned, specific routes of circulation are unclear and may well involve human sources of contamination. Examination of water sources in particular may be difficult due to dilution and their natural flow. Also, as meat is comparatively easy to examine, and is frequently suspected of being a source of spread, there is some bias in favour of studying this vehicle. Such complexities mean that, with the evidence currently available, it is not possible to prioritise the importance of potential risk pathways and circulation routes.

  16. Natural circulation decay heat removal from an SP-100, 550 kWe power system for a lunar outpost

    NASA Astrophysics Data System (ADS)

    El-Genk, Mohamed S.; Xue, Huimin

    1992-06-01

    This research investigated the decay heat removal from the SP-100 reactor core of a 550-kWe power system for a lunar outpost by natural circulation of lithium coolant. A transient model that simulates the decay heat removal loop (DHRL) of the power system was developed and used to assess the system's decay heat removal capability. The effects of the surface area of the decay heat rejection radiator, the dimensions of the decay heat exchanger (DHE) flow duct, the elevation of the DHE, and the diameter of the rise and down pipes in the DHRL on the decay heat removal capability were examined. Also, to determine the applicability of test results at earth gravity to actual system performance on the lunar surface, the effect of the gravity constant (1 g and 1/6 g) on the thermal behavior of the system after shutdown was investigated.

  17. Steady state boiling crisis in a helium vertically heated natural circulation loop - Part 2: Friction pressure drop lessening

    NASA Astrophysics Data System (ADS)

    Furci, H.; Baudouy, B.; Four, A.; Meuris, C.

    2016-01-01

    Experiments were conducted on a 2-m high two-phase helium natural circulation loop operating at 4.2 K and 1 atm. Two heated sections with different internal diameter (10 and 6 mm) were tested. The power applied on the heated section wall was controlled in increasing and decreasing sequences, and temperature along the section, mass flow rate and pressure drop evolutions were registered. The post-CHF regime was studied watching simultaneously the evolution of boiling crisis onset along the test section and the evolution of pressure drop and mass flow rate. A significant lessening of friction was observed simultaneous to the development of the post-CHF regime, accompanied by a mass flow rate increase, which lets suppose that the vapor film in the film boiling regime acts as a lubricant. A model was created based on this idea and on heat transfer considerations. The predictions by this model are satisfactory for the low quality post-CHF regime.

  18. Natural circulation decay heat removal from an SP-100, 550 kWe power system for a lunar outpost

    NASA Technical Reports Server (NTRS)

    El-Genk, Mohamed S.; Xue, Huimin

    1992-01-01

    This research investigated the decay heat removal from the SP-100 reactor core of a 550-kWe power system for a lunar outpost by natural circulation of lithium coolant. A transient model that simulates the decay heat removal loop (DHRL) of the power system was developed and used to assess the system's decay heat removal capability. The effects of the surface area of the decay heat rejection radiator, the dimensions of the decay heat exchanger (DHE) flow duct, the elevation of the DHE, and the diameter of the rise and down pipes in the DHRL on the decay heat removal capability were examined. Also, to determine the applicability of test results at earth gravity to actual system performance on the lunar surface, the effect of the gravity constant (1 g and 1/6 g) on the thermal behavior of the system after shutdown was investigated.

  19. Low Circulating Natural Killer Cell Counts are Associated With Severe Disease in Patients With Common Variable Immunodeficiency

    PubMed Central

    Ebbo, Mikael; Gérard, Laurence; Carpentier, Sabrina; Vély, Frédéric; Cypowyj, Sophie; Farnarier, Catherine; Vince, Nicolas; Malphettes, Marion; Fieschi, Claire; Oksenhendler, Eric; Schleinitz, Nicolas; Vivier, Eric

    2016-01-01

    Natural Killer (NK) cells have been shown to exert antiviral and antitumoural activities. Nevertheless most available data are derived from mouse models and functions of these cells in human remain unclear. To evaluate the impact of low circulating NK cell counts and to provide some clues to the role of NK cells in natural conditions, we studied a large cohort of patients with common variable immunodeficiency (CVID) included in a multicenter cohort of patients with primary hypogammaglobulinaemia. Patients were classified into three groups on the basis of their NK cell counts: severe and mild NK cell lymphopenia (< 50 and 50–99 × 106/L respectively), and normal NK cell counts (> 100 × 106/L). Clinical events were analyzed and compared between these three groups of patients. During study period, 457 CVID patients were included: 99 (21.7%) with severe NK cell lymphopenia, 118 (25.8%) with mild NK cell lymphopenia and 240 (52.5%) with normal NK cell counts. Non-infectious complications (57% vs. 36% and 35%), and, particularly, granulomatous complications (25.3% vs. 13.6% and 8.8%), were more frequent in patients with severe NK cell lymphopenia than in other groups. Invasive infections (68.7% vs. 60.2% and 48.8%), including bacteraemia (22.2% vs. 5.9% and 8.3%) and infectious pneumonia (63.6% vs. 59.3% and 44.2%), were also more frequent in this population. However, no difference was observed for viral infections and neoplasms. Low circulating NK cell counts are associated with more severe phenotypes of CVID, which may indicate a protective role of these immune cells against severe bacterial infections and other complications and non-redundant immune functions when the adaptive immune response is not optimal. PMID:27211564

  20. Investigations on natural circulation in reactor models and shutdown heat removal systems for LMFBRs (liquid metal fast breeder reactors)

    SciTech Connect

    Hoffmann, H.; Weinberg, D.; Marten, K. ); Ieda, Yoshiaki )

    1989-11-01

    For sodium-cooled pool-type reactors, studies have been undertaken to remove the decay heat by natural convection alone, as in the case of failure of all power supplies. For this purpose, four immersion coolers (ICs), two each installed at a 180-deg circumferential position with respect to the others, are arranged within the reactor tank. They are connected with natural-drift air coolers through independent intermediate circuits. The primary sodium in the tank as well as the secondary sodium in the intermediate loop circulate by natural convection. The general functioning of this passive shutdown decay heat removal (DHR) system is demonstrated in 1:20 and 1:5 scale test models using water as a simulant fluid for sodium. The model design is based on the thermohydraulics similarity criteria. In the RAMONA three-dimensional 1:20 scale model, experiments were carried out to clarify the steady-state in-vessel thermohydraulics for different parameter combinations (core power, radial power distribution across the core, DHR by 2 or 4 ICs in operation, above-core structure geometry and position, different IC designs). For all mentioned parameters, temperatures and their fluctuations were measured and used to indicate isotherms and lines of identical temperature fluctuations. The flow patterns were observed visually. The experiments were recalculated by an updated version of the single-phase three-dimensional thermohydraulics code COMMIX.

  1. Natural Circulation in Water Cooled Nuclear Power Plants Phenomena, models, and methodology for system reliability assessments

    SciTech Connect

    Jose Reyes

    2005-02-14

    In recent years it has been recognized that the application of passive safety systems (i.e., those whose operation takes advantage of natural forces such as convection and gravity), can contribute to simplification and potentially to improved economics of new nuclear power plant designs. In 1991 the IAEA Conference on ''The Safety of Nuclear Power: Strategy for the Future'' noted that for new plants the use of passive safety features is a desirable method of achieving simplification and increasing the reliability of the performance of essential safety functions, and should be used wherever appropriate''.

  2. Step-by-step synchronous variations of planetary natural processes in 1997-1998 and their uniform mechanism: phenomenon of "galloping of the core"

    NASA Astrophysics Data System (ADS)

    Barkin, Yu. V.

    2009-04-01

    "For an explanation of observably step-by-step variations of geodynamic and geophysical processes the mechanism of sharp sporadic relative displacements of the core and the mantle and deformations of the mantle in the certain periods of time (the phenomenon of "galloping of the core") is offered. Apparently, this mechanism results in spasmodic variations of axial rotation of the Earth, causes gallop in value of a phase of Chandler motion of a pole, to sharp changes of the intense condition in zones of catastrophes" ([1], p. 61). According to geodynamic model the step changes first of all should to be observed in motion of a geocenter as it reflects relative displacement of the centers of mass of the core and the mantle [1]. A gallop of natural processes in northern and southern hemispheres is characterized by the certain asymmetry. In result the step changes are tested by trend components of secular changes of parameters. In another words and activity (intensity) and trends of its secular changes test synchronous certain steps. Geocenter. According to observation data of DORIS spasmodic changes of polar rotation of a geocenter in a projection to an equatorial coordinate plane in 1997-1999 are revealed. On data DORIS in values of polar coordinate of a geocenter were observed gallop up to 20-30 cm. Changes of trend components have tested gallop which can be estimated in -2 mm in coordinate x, -5 mm in coordinate y and in -10 mm in coordinate z. Trajectory of a geocenter. A bend of a trajectory of long - periodic trend "trace" of a geocenter (its epicentre) on a surface of the Earth in 1997-1998 has been discovered (Zotov, Barkin, Lyubushin, 2008). It serves as direct confirmation of the assumption about a fundamental role of interaction and the forced relative displacements of the basic shells of the Earth, first of all the core and the mantle, both their stimulating and directing role in all planetary processes (Barkin, 2002). Gravitational field. On the data of

  3. Do general circulation models underestimate the natural variability in the artic climate?

    SciTech Connect

    Battisti, D.S.; Bitz, C.M.; Moritz, R.E.

    1997-08-01

    The authors examine the natural variability of the arctic climate system simulated by two very different models: the Geophysical Fluid Dynamics Laboratory (GFDL) global climate model, and an area-averaged model of the arctic atmosphere-sea ice-upper-ocean system called the polar cap climate model, the PCCM. A 1000-yr integration of the PCCM is performed in which the model is driven by a prescribed, stochastic atmospheric energy flux convergence (D), which has spectral characteristics that are identical to the spectra of the observed D. The standard deviation of the yearly mean sea ice thickness from this model is 0.85 m; the mean sea ice thickness is 3.1 m. In contrast, the standard deviation of the yearly averaged sea ice thickness in the GFDL climate model is found to be about 6% of the climatological mean thickness and only 24% of that simulated by the PCCM. A series of experiments is presented to determine the cause of these disparate results. First, after changing the treatment of sea ice and snow albedo in the (standard) PCCM model to be identical thermodynamically to that in the GFDL model, the PCCM is driven with D from the GFDL control integration to demonstrate that the PCCM model produces an arctic climate similar to that of the GFDL model. Integrations of the PCCM are then examined in which the different prescriptions of the sea ice treatment (GFDL vs standard PCCM) and D (GFDL vs observed) are permutated. The authors present calculations that indicate the variability in the sea ice thickness is extremely sensitive to the spectrum of the atmospheric energy flux convergence. A conservative best estimate for the amplitude of the natural variability in the arctic sea ice volume is presented.The results suggest that most of the global climate models that have been used to evaluate climate change may also have artificially quiescent variability in the Arctic. 24 refs., 6 figs., 3 tabs.

  4. HIV Type 1 Integrase Natural Polymorphisms in Viral Variants Circulating in FSU Countries.

    PubMed

    Lapovok, Ilya; Laga, Vita; Kazennova, Elena; Bobkova, Marina

    2017-08-15

    Natural variability of integrase (IN) across HIV-1 variants may influence the emergence of resistant viruses. The most apparent explanation of these fact is the IN polymorphism and the associated differences in codon usage, which, in turn, influence the probability and the terms of DRMs acquisition. Possible mechanisms by which polymorphisms affect DRMs emergence remain disputed and should still be clarified because these substitutions may be associated with a reduced activity of some INSTIs and may impact on ART regimen choice depending of HIV-1 subtype. The aim of this work was to assess the prevalence of naturally occurring polymorphisms within the HIV-1 integrase gene, which might influence the susceptibility to INSTIs, among the patients from Russia and former USSR countries, according to HIV-1 subtypes. A study involved 506 HIV-1 IN sequences of INSTI-naive patients from Russia, Ukraine, Armenia, Kyrgyzstan, Kazakhstan, Uzbekistan, Belarus, and Georgia. Among them, 194 sequences were newly obtained in this study and 312 were downloaded from Los-Alamos database. The proviral DNA was sequenced using an in-house PCR protocol designed on the basis of a well-conserved integrase region in order to detect all HIV-1 variants. The phylogenetic analyses based on IN population sequencing found subtype A6 being the most prevalent (259) (51.2%) in the collection studied, followed by subtype G (36) (7.1%), AG-recombinants (148) (29.3%), subtype B (50) (9.9%), and CRF03_AB (5) (1,0%). The major INSTI resistance-associated mutations (DRMs) were found only in two A6 samples. The prevalence of minor/accessory substitutions depended on HIV-1 variants, while the most notable findings were L74I in subtype A6 (93.1%) and E157Q in subtype B (44.0%). Most of minor DRMs and polymorphic substitutions were concentrated in the central catalytic domain of the IN molecule. Both the DDE triad and HHCC zinc binding motifs were fully conserved. The results of the study suggest a very low

  5. Simulation experiments on two-phase natural circulation in a freon-113 flow visualization loop

    SciTech Connect

    Lee, Sang Yong; Ishii, Mamoru

    1988-01-01

    In order to study the two-phase natural circulaton and flow termination during a small break loss of coolant accident in LWR, simulation experiments have been performed using a Freon-113 flow visualization loop. The main focus of the present experiment was placed on the two-phase flow behavior in the hot-leg U-bend typical of B and W LWR systems. The loop was built based on the two-phase flow scaling criteria developed under this program to find out the effect of fluid properties, phase changes and coupling between hydrodynamic and heat transfer phenomena. Significantly different flow behaviors have been observed due to the non-equilibrium phase change phenomena such as the flashing and condensation on the Freon loop in comparison with the previous adiabatic experiment. The phenomena created much more unstable hydrodynamic conditions which lead to cyclic or oscillatory flow behaviors. Also, the void distribution and primary loop flow rate were measured in detail in addition to the important key paramaters, such as the power input, loop friction and the liquid level inside the simulated steam generator.

  6. Prediction of Severe Accident Counter Current Natural Circulation Flows in the Hot Leg of a Pressurized Water Reactor

    SciTech Connect

    Boyd, Christopher F.

    2006-07-01

    During certain phases of a severe accident in a pressurized water reactor (PWR), the core becomes uncovered and steam carries heat to the steam generators through natural circulation. For PWR's with U-tube steam generators and loop seals filled with water, a counter current flow pattern is established in the hot leg. This flow pattern has been experimentally observed and has been predicted using computational fluid dynamics (CFD). Predictions of severe accident behavior are routinely carried out using severe accident system analysis codes such as SCDAP/RELAP5 or MELCOR. These codes, however, were not developed for predicting the three-dimensional natural circulation flow patterns during this phase of a severe accident. CFD, along with a set of experiments at 1/7. scale, have been historically used to establish the flow rates and mixing for the system analysis tools. One important aspect of these predictions is the counter current flow rate in the nearly 30 inch diameter hot leg between the reactor vessel and steam generator. This flow rate is strongly related to the amount of energy that can be transported away from the reactor core. This energy transfer plays a significant role in the prediction of core failures as well as potential failures in other reactor coolant system piping. CFD is used to determine the counter current flow rate during a severe accident. Specific sensitivities are completed for parameters such as surge line flow rates, hydrogen content, as well as vessel and steam generator temperatures. The predictions are carried out for the reactor vessel upper plenum, hot leg, a portion of the surge line, and a steam generator blocked off at the outlet plenum. All predictions utilize the FLUENT V6 CFD code. The volumetric flow in the hot leg is assumed to be proportional to the square root of the product of normalized density difference, gravity, and hydraulic diameter to the 5. power. CFD is used to determine the proportionality constant in the range

  7. Absence of circulating natural killer (NK) cells in a child with erythrophagocytic lymphohistiocytosis lacking NK cell activity

    SciTech Connect

    Kawai, H.; Komiyama, A.; Aoyama, K.; Miyagawa, Y.; Akabane, T.

    1988-06-01

    A 5-year-old girl who was diagnosed as having erythrophagocytic lymphohistiocytosis died at age 9 years. Peripheral lymphocytes from the patient persistently lacked natural killer (NK) cell activity during the 4-year observation period: the percent lysis values as measured by a 4-hr /sup 51/Cr release assay at a 40:1 effector:target ratio were below 1.0% against K562 and Molt-4 cells as compared with the normal lymphocyte value (mean +/- SD) of 46.2% +/- 5.8% and 43.9% +/- 6.7%, respectively. The patient's lymphocytes never developed NK cell activity by their incubation with target cells for longer time periods or by their stimulation with interferon-alpha, interleukin-2, or polyinosinic-polycytidilic acid. Single cell-in-agarose assay showed the absence of target-binding cells (TBCs): TBC numbers were below 0.3% as compared with the normal lymphocyte value of 8.1% +/- 1.3% (mean +/- SD). Flow cytometry showed a marked decrease in Leu-7+ cells (1.7%) and the absence of Leu-11+ cells (0.4%) in the peripheral blood. These results first demonstrate a case of erythrophagocytic lymphohistiocytosis in which there is the lack of NK cell activity due to the absence of circulating NK cells.

  8. Transient analysis of subcritical/supercritical carbon dioxide based natural circulation loop with end heat exchangers: experimental study

    NASA Astrophysics Data System (ADS)

    Yadav, Ajay Kumar; Ramgopal, Maddali; Bhattacharyya, Souvik

    2017-09-01

    Carbon dioxide (CO2) based natural circulation loops (NCLs) has gained attention due to its compactness with higher heat transfer rate. In the present study, experimental investigations have been carried out to capture the transient behaviour of a CO2 based NCL operating under subcritical as well as supercritical conditions. Water is used as the external fluid in cold and hot heat exchangers. Results are obtained for various inlet temperatures (323-353 K) of water in the hot heat exchanger and a fixed inlet temperature (305 K) of cooling water in the cold heat exchanger. Effect of loop operating pressure (50-90 bar) on system performance is also investigated. Effect of loop tilt in two different planes (XY and YZ) is also studied in terms of transient as well as steady state behaviour of the loop. Results show that the time required to attain steady state decreases as operating pressure of the loop increases. It is also observed that the change in temperature of loop fluid (CO2) across hot or cold heat exchanger decreases as operating pressure increases.

  9. Transient analysis of subcritical/supercritical carbon dioxide based natural circulation loop with end heat exchangers: experimental study

    NASA Astrophysics Data System (ADS)

    Yadav, Ajay Kumar; Ramgopal, Maddali; Bhattacharyya, Souvik

    2017-04-01

    Carbon dioxide (CO2) based natural circulation loops (NCLs) has gained attention due to its compactness with higher heat transfer rate. In the present study, experimental investigations have been carried out to capture the transient behaviour of a CO2 based NCL operating under subcritical as well as supercritical conditions. Water is used as the external fluid in cold and hot heat exchangers. Results are obtained for various inlet temperatures (323-353 K) of water in the hot heat exchanger and a fixed inlet temperature (305 K) of cooling water in the cold heat exchanger. Effect of loop operating pressure (50-90 bar) on system performance is also investigated. Effect of loop tilt in two different planes (XY and YZ) is also studied in terms of transient as well as steady state behaviour of the loop. Results show that the time required to attain steady state decreases as operating pressure of the loop increases. It is also observed that the change in temperature of loop fluid (CO2) across hot or cold heat exchanger decreases as operating pressure increases.

  10. Laser anemometry measurements of natural circulation flow in a scale model PWR reactor system. [Pressurized Water Reactor

    NASA Technical Reports Server (NTRS)

    Kadambi, J. R.; Schneider, S. J.; Stewart, W. A.

    1986-01-01

    The natural circulation of a single phase fluid in a scale model of a pressurized water reactor system during a postulated grade core accident is analyzed. The fluids utilized were water and SF6. The design of the reactor model and the similitude requirements are described. Four LDA tests were conducted: water with 28 kW of heat in the simulated core, with and without the participation of simulated steam generators; water with 28 kW of heat in the simulated core, with the participation of simulated steam generators and with cold upflow of 12 lbm/min from the lower plenum; and SF6 with 0.9 kW of heat in the simulated core and without the participation of the simulated steam generators. For the water tests, the velocity of the water in the center of the core increases with vertical height and continues to increase in the upper plenum. For SF6, it is observed that the velocities are an order of magnitude higher than those of water; however, the velocity patterns are similar.

  11. Transmission-blocking activity of tafenoquine (WR-238605) and artelinic acid against naturally circulating strains of Plasmodium vivax in Thailand.

    PubMed

    Ponsa, Narong; Sattabongkot, Jetsumon; Kittayapong, Pattamaporn; Eikarat, Nantana; Coleman, Russell E

    2003-11-01

    The sporontocidal activity of tafenoquine (WR-238605) and artelinic acid was determined against naturally circulating isolates of Plasmodium vivax in western Thailand. Primaquine was used as a negative control and a dihydroacridine-dione (WR-250547) was used as a positive control. Laboratory-reared Anopheles dirus mosquitoes were infected with P. vivax by allowing mosquitoes to feed on blood (placed in an artificial-membrane feeding apparatus) collected from gametocytemic volunteers reporting to local malaria clinics in Tak province, Thailand. Four days post-infection, mosquitoes were refed on uninfected mice treated 90 minutes earlier with a given drug. Drug activity was determined by assessing oocyst and sporozoite development. Neither primaquine nor artelinic acid affected oocyst or sporozoite development at a dose of 100 mg of base drug/kg of mouse body weight. In contrast, tafenoquine and WR-250547 affected sporogonic development at doses as low as 25.0 and 0.39 mg/kg, respectively. The potential role of these compounds in the prevention of malaria transmission is discussed, as are alternative strategies for the use of transmission-blocking antimalarial drugs.

  12. Circadian rhythm in circulating CD16-positive natural killer (NK) cells in macaque monkeys, implication of plasma cortisol levels.

    PubMed

    Terao, Keiji; Suzuki, Juri; Ohkura, Satoshi

    2002-10-01

    The daily change in both percentage and absolute number of circulating major lymphocyte subset was determined with young Japanese monkeys and rhesus monkeys. The blood sample was collected at four hour-intervals beginning at 16:00 for 24 hours under the condition of applying tethering system by which blood samples could be collected without restraint. During the dark period (from 20:00 to 08:00), the number of peripheral lymphocytes increased and that of granulocytes decreased, resulting in no significant change in the number of total peripheral white blood cells. The absolute number of CD4+ T, CD8+ T, and CD20+ B cells showed the significant daily change similar to that in number of peripheral lymphocytes, indicating no proportional change in these subsets. The typical proportional change was observed in CD16+ natural killer (NK) cells and the percentage of CD16+ cells decreased during dark period (from 20:00 to 04:00) and increased in the morning (from 08:00 to 12:00). The NK activity determined by killing K562 target cells showed the same changing pattern as that of percentage in CD16+ NK cells. The changing pattern of both percentage and activity of NK cells was consistent with that of plasma cortisol levels. In addition, the intravenous injection of 300 g/kg of cortisol induced increase in plasma cortisol levels and decrease in percentage of CD16+ NK cells during the first 60 min after cortisol injection. These results strongly suggest that the levels of peripheral functional CD16+ NK cells might be directly regulated by plasma cortisol level in macaque monkeys.

  13. Nutcracker phenomenon and nutcracker syndrome.

    PubMed

    Kurklinsky, Andrew K; Rooke, Thom W

    2010-06-01

    Nutcracker phenomenon refers to compression of the left renal vein, most commonly between the aorta and the superior mesenteric artery, with impaired blood outflow often accompanied by distention of the distal portion of the vein. The nutcracker syndrome (NCS) is the clinical equivalent of nutcracker phenomenon characterized by a complex of symptoms with substantial variations. Depending on specific manifestations, NCS may be encountered by different medical specialists. Although it may be associated with substantial morbidity, the diagnosis of NCS is often difficult and is commonly delayed. Diagnostic and treatment criteria are not well established, and the natural history of NCS is not well understood. We performed an initial review of the literature through MEDLINE, searching from 1950 to date and using the keywords nutcracker syndrome, nutcracker phenomenon, and renal vein entrapment. We performed additional reviews based on the literature citations of the identified articles. We attempted to elucidate clinical relevance of these conditions and their prominent features and to summarize professional experience.

  14. Evidences of the circulation of natural philosophical knowledge about Brazil in a 1763 manuscript by António Nunes Ribeiro Sanches.

    PubMed

    Conceição, Gisele C

    2017-01-01

    António Nunes Ribeiro Sanches was a Portuguese physician and the author of several works about education and science in Portugal and its Empire. Many of these texts circulated and were made public through letters written by him and sent to other intellectuals. This article sheds light on an unpublished manuscript written by Sanches in 1763, in which he argued for the recognition of Brazilian natural resources and their exploitation for trade and medicine.

  15. Treatment of Raynaud's phenomenon.

    PubMed

    García-Carrasco, Mario; Jiménez-Hernández, Mario; Escárcega, Ricardo O; Mendoza-Pinto, Claudia; Pardo-Santos, Rodrigo; Levy, Roger; Maldonado, Claudio Galarza; Chávez, Gonzalo Pérez; Cervera, Ricard

    2008-10-01

    Raynaud's phenomenon is an episodic vasospasm of the peripheral arteries, causing pallor followed by cyanosis and redness with pain and sometimes paraesthesia, and, rarely, ulceration of the fingers and toes. Primary or idiopathic Raynaud's phenomenon (Raynaud's disease) occurs without an underlying disease. Secondary Raynaud's phenomenon (Raynaud's syndrome) occurs in association with an underlying disease. Initially conservative, non-pharmacologic approach is important for these patients, although pharmacologic therapy may ultimately be necessary. Advances in vascular physiology have showed the role of the endothelium as well as endothelium-independent mechanisms in the altered vasoregulation of Raynaud's phenomenon. This has opened promising therapeutic avenues, and it is likely that therapies targeted towards specific pathophysiologic steps become available in the near future.

  16. A new phenomenon?

    NASA Astrophysics Data System (ADS)

    Ganci, S.

    2017-03-01

    This letter describes an interesting optical phenomenon engaging the reflected images of a new tube LED lamp (an array of high luminosity LEDs substituting the old fluorescent lamps) on any convex glossy black surface.

  17. The Root Pressure Phenomenon

    ERIC Educational Resources Information Center

    Marsh, A. R.

    1972-01-01

    Describes experiments demonstrating that root pressure in plants is probably controlled by a circadian rhythm (biological clock). Root pressure phenomenon plays significant part in water transport in contradiction with prevalent belief. (PS)

  18. The Root Pressure Phenomenon

    ERIC Educational Resources Information Center

    Marsh, A. R.

    1972-01-01

    Describes experiments demonstrating that root pressure in plants is probably controlled by a circadian rhythm (biological clock). Root pressure phenomenon plays significant part in water transport in contradiction with prevalent belief. (PS)

  19. Increased circulating microRNAs miR-342-3p and miR-21-5p in natural sheep prion disease.

    PubMed

    Sanz Rubio, David; López-Pérez, Óscar; de Andrés Pablo, Álvaro; Bolea, Rosa; Osta, Rosario; Badiola, Juan J; Zaragoza, Pilar; Martín-Burriel, Inmaculada; Toivonen, Janne M

    2017-02-01

    Scrapie is a transmissible spongiform encephalopathy (TSE), or prion disease, of sheep and goats. As no simple diagnostic tests are yet available to detect TSEs in vivo, easily accessible biomarkers could facilitate the eradication of scrapie agents from the food chain. To this end, we analysed by quantitative reverse transcription PCR a selected set of candidate microRNAs (miRNAs) from circulating blood plasma of naturally infected, classical scrapie sheep that demonstrated clear scrapie symptoms and pathology. Significant scrapie-associated increase was repeatedly found for miR-342-3p and miR-21-5p. This is the first demonstration, to our knowledge, of circulating miRNA alterations in any animal suffering from TSE. Genome-wide expression studies are warranted to investigate the true depth of miRNA alterations in naturally occurring TSEs, especially in presymptomatic animals, as the presented study demonstrates the potential feasibility of miRNAs as circulating TSE biomarkers.

  20. A study on the effect of various design parameters on the natural circulation flow rate of the ex-vessel core catcher cooling system of EU-APR1400

    SciTech Connect

    Rhee, B. W.; Ha, K. S.; Park, R. J.; Song, J. H.

    2012-07-01

    In this paper, a study on the effect of various design parameters such as the channel gap width, heat flux distribution, down-comer pipe size and two-phase flow slip ratio on the natural circulation flow rate is performed based on a physical model for a natural circulation flow along the flow path of the ex-vessel core catcher cooling system of an EU-APR1400, and these effects on the natural circulation flow rate are analyzed and compared with the minimum flow rate required for the safe operation of the system. (authors)

  1. The Lazarus phenomenon

    PubMed Central

    Adhiyaman, Vedamurthy; Adhiyaman, Sonja; Sundaram, Radha

    2007-01-01

    Even though Lazarus phenomenon is rare, it is probably under reported. There is no doubt that Lazarus phenomenon is a reality but so far the scientific explanations have been inadequate. So far the only plausible explanation at least in some cases is auto-PEEP and impaired venous return. In patients with PEA or asystole, dynamic hyperinflation should considered as a cause and a short period of apnoea (30-60 seconds) should be tried before stopping resuscitation. Since ROSC occurred within 10 minutes in most cases, patients should be passively monitored for at least 10 minutes after the cessation of CPR before confirming death. PMID:18065707

  2. A scaling study of the natural circulation flow of the ex-vessel core catcher cooling system of EU-APR1400 for designing a scale-down test facility for design verification

    SciTech Connect

    Rhee, B. W.; Ha, K. S.; Park, R. J.; Song, J. H.; Revankar, S. T.

    2012-07-01

    In this paper a scaling study on the steady state natural circulation flow along the flow path of the ex vessel core catcher cooling system of EU-APR1400 is described, and the scaling criteria for reproducing the same steady state thermalhydraulic characteristics of the natural circulation flow as a prototype core catcher cooling system in the scale-down test facility are derived in terms of the down-comer pipe diameter and orifice resistance. (authors)

  3. The Leidenfrost Phenomenon

    ERIC Educational Resources Information Center

    Curzon, F. L.

    1978-01-01

    Describes four demonstrations of the Leidenfrost phenomenon; floating of liquid drops on their own vapor above a hot surface, delayed quenching of red-hot brass by water, explosion of vessels containing suspended liquid droplets, and momentary incombustibility of living tissue immersed in boiling oil. (Author/GA)

  4. Raynaud's phenomenon (primary)

    PubMed Central

    2008-01-01

    Introduction Raynaud’s phenomenon is an episodic vasospasm of the peripheral arteries, causing pallor followed by cyanosis and redness with pain and sometimes paraesthesia. On rare occasions it can lead to ulceration of the fingers and toes (and in some cases of the ears or nose). This review focuses on primary (idiopathic) Raynaud's phenomenon occurring in the absence of an underlying disease. The prevalence of primary Raynaud's phenomenon varies by sex, country, and exposure to workplace vibration. Methods and outcomes We conducted a systematic review and aimed to answer the following clinical question: What are the effects of treatments for primary Raynaud’s phenomenon? We searched: Medline, Embase, The Cochrane Library, and other important databases up to May 2008 (Clinical Evidence reviews are updated periodically, please check our website for the most up-to-date version of this review). We included harms alerts from relevant organisations such as the US Food and Drug Administration (FDA) and the UK Medicines and Healthcare products Regulatory Agency (MHRA). Results We found 15 systematic reviews, RCTs, or observational studies that met our inclusion criteria. We performed a GRADE evaluation of the quality of evidence for interventions. Conclusions In this systematic review we present information relating to the effectiveness and safety of the following interventions: amlodipine, diltiazem, exercise, inositol nicotinate, keeping warm, moxisylyte (thymoxamine), naftidrofuryl oxalate, nicardipine, nifedipine, prazosin, and smoking cessation. PMID:19445785

  5. Raynaud's phenomenon (primary)

    PubMed Central

    2011-01-01

    Introduction Raynaud’s phenomenon is an episodic vasospasm of the peripheral arteries, causing pallor, followed by cyanosis and redness with pain, and sometimes paraesthesia. On rare occasions it can lead to ulceration of the fingers and toes (and in some cases of the ears or nose). This review focuses on primary (idiopathic) Raynaud's phenomenon, occurring in the absence of an underlying disease. The prevalence of primary Raynaud's phenomenon varies by sex, country, and exposure to workplace vibration. Methods and outcomes We conducted a systematic review and aimed to answer the following clinical question: What are the effects of treatments for primary Raynaud’s phenomenon? We searched: Medline, Embase, The Cochrane Library, and other important databases up to May 2010 (Clinical Evidence reviews are updated periodically; please check our website for the most up-to-date version of this review). We included harms alerts from relevant organisations such as the US Food and Drug Administration (FDA) and the UK Medicines and Healthcare products Regulatory Agency (MHRA). Results We found 16 systematic reviews, RCTs, or observational studies that met our inclusion criteria. We performed a GRADE evaluation of the quality of evidence for interventions. Conclusions In this systematic review we present information relating to the effectiveness and safety of the following interventions: amlodipine, diltiazem, exercise, inositol nicotinate, keeping warm, moxisylyte (thymoxamine), naftidrofuryl oxalate, nicardipine, nifedipine, prazosin, and smoking cessation. PMID:21401971

  6. Raynaud's phenomenon (primary)

    PubMed Central

    2013-01-01

    Introduction Raynaud’s phenomenon is an episodic, reversible vasospasm of the peripheral arteries (usually digital). It causes pallor, followed by cyanosis and/or redness, often with pain and, at times, paraesthesia. On rare occasions, it can lead to ulceration of the fingers and toes (and, in some cases, of the ears or nose). This review focuses on primary (idiopathic) Raynaud's phenomenon, occurring in the absence of an underlying disease. The prevalence of primary Raynaud's phenomenon varies by sex, country, and exposure to workplace vibration. Methods and outcomes We conducted a systematic review and aimed to answer the following clinical question: What are the effects of drug treatments for primary Raynaud’s phenomenon? We searched: Medline, Embase, The Cochrane Library, and other important databases up to August 2013 (Clinical Evidence reviews are updated periodically; please check our website for the most up-to-date version of this review). We included harms alerts from relevant organisations such as the US Food and Drug Administration (FDA) and the UK Medicines and Healthcare products Regulatory Agency (MHRA). Results We found 9 systematic reviews, RCTs, or observational studies that met our inclusion criteria. We performed a GRADE evaluation of the quality of evidence for interventions. Conclusions In this systematic review we present information relating to the effectiveness and safety of the following interventions: amlodipine, diltiazem, nicardipine, and nifedipine. PMID:24112969

  7. The Leidenfrost Phenomenon

    ERIC Educational Resources Information Center

    Curzon, F. L.

    1978-01-01

    Describes four demonstrations of the Leidenfrost phenomenon; floating of liquid drops on their own vapor above a hot surface, delayed quenching of red-hot brass by water, explosion of vessels containing suspended liquid droplets, and momentary incombustibility of living tissue immersed in boiling oil. (Author/GA)

  8. Nutcracker Phenomenon and Nutcracker Syndrome

    PubMed Central

    Kurklinsky, Andrew K.; Rooke, Thom W.

    2010-01-01

    Nutcracker phenomenon refers to compression of the left renal vein, most commonly between the aorta and the superior mesenteric artery, with impaired blood outflow often accompanied by distention of the distal portion of the vein. The nutcracker syndrome (NCS) is the clinical equivalent of nutcracker phenomenon characterized by a complex of symptoms with substantial variations. Depending on specific manifestations, NCS may be encountered by different medical specialists. Although it may be associated with substantial morbidity, the diagnosis of NCS is often difficult and is commonly delayed. Diagnostic and treatment criteria are not well established, and the natural history of NCS is not well understood. We performed an initial review of the literature through MEDLINE, searching from 1950 to date and using the keywords nutcracker syndrome, nutcracker phenomenon, and renal vein entrapment. We performed additional reviews based on the literature citations of the identified articles. We attempted to elucidate clinical relevance of these conditions and their prominent features and to summarize professional experience. PMID:20511485

  9. Raynaud's phenomenon (secondary)

    PubMed Central

    2008-01-01

    Introduction Raynaud’s phenomenon is episodic vasospasm of the peripheral vessels, causing pallor followed by cyanosis and redness with pain and sometimes paraesthesia, and, rarely, ulceration of the fingers and toes. It presents as episodic colour changes of the digits, usually in response to cold exposure or stress. The classic triphasic colour change is white (ischaemia), then blue (deoxygenation), then red (reperfusion). Raynaud’s phenomenon can be primary (idiopathic) or secondary to several different conditions and causes. This review deals with secondary Raynaud’s phenomenon. Methods and outcomes We conducted a systematic review and aimed to answer the following clinical questions: What are the effects of self-help measures for secondary Raynaud’s phenomenon? What are the effects of drug treatments for secondary Raynaud’s phenomenon? We searched: Medline, Embase, The Cochrane Library, and other important databases up to May 2007 (Clinical Evidence reviews are updated periodically; please check our website for the most up-to-date version of this review). We included harms alerts from relevant organisations such as the US Food and Drug Administration (FDA) and the UK Medicines and Healthcare products Regulatory Agency (MHRA). Results We found 25 systematic reviews, RCTs, or observational studies that met our inclusion criteria. We performed a GRADE evaluation of the quality of evidence for interventions. Conclusions In this systematic review, we present information relating to the effectiveness and safety of the following interventions: alpha-blockers; angiotensin-converting enzyme (ACE) inhibitors; angiotensin II receptor antagonists; antithrombotics/inhibitors of platelet aggregation; biofeedback; calcium channel blockers; endothelin-1 receptor antagonists; glyceryl trinitrate (transdermal); hand exercises; inositol nicotinate; moxisylyte; naftidrofuryl oxylate; phosphodiesterase inhibitors; prostaglandins (oral, intravenous); relaxation therapy

  10. A Synoptic View of the Ventilation and Circulation of Antarctic Bottom Water from Chlorofluorocarbons and Natural Tracers.

    PubMed

    Purkey, Sarah G; Smethie, William M; Gebbie, Geoffrey; Gordon, Arnold L; Sonnerup, Rolf E; Warner, Mark J; Bullister, John L

    2017-09-06

    Antarctic Bottom Water (AABW) is the coldest, densest, most prolific water mass in the global ocean. AABW forms at several distinct regions along the Antarctic coast and feeds into the bottom limb of the meridional overturning circulation, filling most of the global deep ocean. AABW has warmed, freshened, and declined in volume around the globe in recent decades, which has implications for the global heat and sea level rise budgets. Over the past three decades, the use of tracers, especially time-varying tracers such as chlorofluorocarbons, has been essential to our understanding of the formation, circulation, and variability of AABW. Here, we review three decades of temperature, salinity, and tracer data and analysis that have led to our current knowledge of AABW and how the southern component of deep-ocean ventilation is changing with time. Expected final online publication date for the Annual Review of Marine Science Volume 10 is January 3, 2018. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

  11. Overall results of and lessons learned from the IAEA CRP on sodium natural circulation test performed during the Phenix end-of-life experiments

    SciTech Connect

    Monti, S.; Toti, A.; Tenchine, D.; Pialla, D.

    2012-07-01

    In 2007, the International Atomic Energy Agency (IAEA) launched the Coordinated Research Project (CRP) 'Control Rod Withdrawal and Sodium Natural Circulation Tests Performed during the Phenix End-of-Life Experiments'. The overall purpose of the CRP, performed within the framework of the IAEA programme in support of innovative fast reactor technology development and deployment, is to improve the Member States' analytical capabilities in the various fields of research and design of sodium-cooled fast reactors through data and codes verification and validation. In particular the CRP, taking advantage of the End-of-Life set of experiments performed before the final shut-down of the French prototype fast breeder power reactor Phenix, aims at improving fast reactor simulation methods and design capabilities in the field of temperature and power distribution evaluation, as well as of the analysis of sodium natural circulation phenomena. The paper presents the overall results of the CRP, including blind calculations and post-test and sensitivity analyses carried out by the CRP participants, as well as lessons learned and recommendations for further future implementations to resolve open issues. (authors)

  12. Study on bubbly flow behavior in natural circulation reactor by thermal-hydraulic simulation tests with SF6-Gas and ethanol liquid

    NASA Astrophysics Data System (ADS)

    Kondo, Yoshiyuki; Suga, Keishi; Hibi, Koki; Okazaki, Toshihiko; Komeno, Toshihiro; Kunugi, Tomoaki; Serizawa, Akimi; Yoneda, Kimitoshi; Arai, Takahiro

    2009-02-01

    An advanced experimental technique has been developed to simulate two-phase flow behavior in a light water reactor (LWR). The technique applies three kinds of methods; (1) use of sulfur-hexafluoride (SF6) gas and ethanol (C2H5OH) liquid at atmospheric temperature and a pressure less than 1.0MPa, where the fluid properties are similar to steam-water ones in the LWR, (2) generation of bubble with a sintering tube, which simulates bubble generation on heated surface in the LWR, (3) measurement of detailed bubble distribution data with a bi-optical probe (BOP), (4) and measurement of liquid velocities with the tracer liquid. This experimental technique provides easy visualization of flows by using a large scale experimental apparatus, which gives three-dimensional flows, and measurement of detailed spatial distributions of two-phase flow. With this technique, we have carried out experiments simulating two-phase flow behavior in a single-channel geometry, a multi-rod-bundle one, and a horizontal-tube-bundle one on a typical natural circulation reactor system. Those experiments have clarified a) a flow regime map in a rod bundle on the transient region between bubbly and churn flow, b) three-dimensional flow behaviour in rod-bundles where inter-subassembly cross-flow occurs, c) bubble-separation behavior with consideration of reactor internal structures. The data have given analysis models for the natural circulation reactor design with good extrapolation.

  13. Steady state boiling crisis in a helium vertically heated natural circulation loop - Part 1: Critical heat flux, boiling crisis onset and hysteresis

    NASA Astrophysics Data System (ADS)

    Furci, H.; Baudouy, B.; Four, A.; Meuris, C.

    2016-01-01

    Experiments were conducted on a 2-m high two-phase helium natural circulation loop operating at 4.2 K and 1 atm. The same loop was used in two experiments with different heated section internal diameter (10 and 6 mm). The power applied on the heated section wall was controlled in increasing and decreasing sequences, and temperature along the section, mass flow rate and pressure drop evolutions were recorded. The values of critical heat flux (CHF) were found at different positions of the test section, and the post-CHF regime was studied. The predictions of CHF by existing correlations were good in the downstream portion of the section, however CHF anomalies have been observed near the entrance, in the low quality region. In resonance with this, the re-wetting of the surface has distinct hysteresis behavior in each of the two CHF regions. Furthermore, hydraulics effects of crisis, namely on friction, were studied (Part 2). This research is the starting point to future works addressing transients conducing to boiling crisis in helium natural circulation loops.

  14. Vacuum phenomenon: Clinical relevance.

    PubMed

    Gohil, Ishan; Vilensky, Joel A; Weber, Edward C

    2014-04-01

    Vacuum phenomenon (VP) is an anatomical entity of potential confusion in the diagnosis and evaluation of joint pathology. Observation of this phenomenon has been demonstrated on basic radiographs, computed tomography, and magnetic resonance imaging. Although VP is most often associated with degenerative joint disease, it is observed with other pathologies. Two problematic scenarios can occur: a false-positive diagnosis of serious pathology instead of benign VP and a false-negative diagnosis of benign VP with a more serious underlying process Despite this potential for confusion, criteria for distinguishing VP from other causes of joint pain and for evaluating a suspected case of VP have not been fully established. We reviewed the literature to determine underlying mechanism, symptomology, associated pathologies, and clinical importance of VP. The formation of VP can be explained by gas solubility, pressure-volume relationships, and human physiology. CT, GRE-MRI, and multipositional views are the best imaging studies to view VP. Although most cases of VP are benign, it can be associated with clinical signs and symptoms. VP outside the spine is an underreported finding on imaging studies. VP should be on the differential diagnosis for joint pain, especially in the elderly. We have proposed criteria for diagnosing VP and generated a basic algorithm for its workup. Underreporting of this phenomenon shows a lack of awareness of VP on the part of physicians. By identifying true anatomic VP, we can prevent harm from suboptimal treatment of patients.

  15. Raynaud's phenomenon in children.

    PubMed

    Ortega Vicente, Elena; Garrido Redondo, Mercedes

    Raynaud's Phenomenon is caused by spasm of the small arteries and arterioles of the fingers. It is triggered by various stimuli including exposure to cold or a stressful event. It may be symmetrical or wrap one end. The appearance of this entity in children is rare. We report the case of a 4 year old male consultation health center by episodes of coldness, pallor and pain in both feet. Copyright © 2015 Elsevier España, S.L.U. and Sociedad Española de Reumatología y Colegio Mexicano de Reumatología. All rights reserved.

  16. Investigation of the nature and stability of the Martian seasonal water cycle with a general circulation model

    NASA Astrophysics Data System (ADS)

    Richardson, Mark I.; Wilson, R. John

    2002-05-01

    We describe the first use of a general circulation model to study the Martian water cycle. Water is treated as a passive tracer, except for ice-albedo coupling. The model is used to assess which mechanisms and water reservoirs are critical to the seasonal evolution of water and specifically the attainment of an interannually repeatable steady state. The model comes to a reasonable steady state with active surface ice and atmospheric vapor and ice reservoirs. A regolith is not necessary. The mechanism of equilibration results from independent parameters controlling the transport of water between the northern polar and the extratropical atmospheres at different seasons. Water export from the northern summer pole results from weak mixing across a strong vapor gradient, dependent upon northern cap temperatures. Import at other seasons depends on stronger mixing and weak vapor gradients, which are history dependent. Equilibration is achieved when the fluxes balance, minus a small net loss to the south. We find that with a southern residual CO2 cap, the water cycle cannot be completely closed. We conclude that the northern summer cap temperature determines the bulk humidity of the atmosphere, all else being equal. We proceed to show that a water cap exposed in southern summer would be unstable with respect to the north for dynamical as well as thermal reasons. At high obliquity (45°), much higher vapor abundances result in more widespread surface ice with seasonal ice caps overlapping in the equinoctial subtropics, producing year-round stability of water ice just north of the equator.

  17. Studies of Phase Change Materials and a Latent Heat Storage Unit Used for a Natural Circulation Cooling/Latent Heat Storage System

    NASA Astrophysics Data System (ADS)

    Sakitani, Katsumi; Honda, Hiroshi

    Experiments were performed to investigate feasibility of using organic materials as a PCM for a latent heat storage unit of a natural circulation cooling/latent heat storage system. This system was designed to cool a shelter accommodating telecommunication equipment located in subtropical deserts or similar regions without using a power source. Taking into account practical considerations and the results of various experiments regarding the thermodynamic properties, thermal degradation, and corrosiveness to metals, lauric acid and iron was selected for the PCM and the latent heat storage unit material, respectively. Cyclic heating and cooling of the latent heat storage unit undergoing solid-liquid phase change was repeated for more than 430 days. The results showed that the heating-cooling curve was almost unchanged between the early stage and the 1,870th cycle. It was concluded that the latent heat storage unit could be used safely for more than ten years as a component of the cooling system.

  18. Phenotypic Features of Circulating Leukocytes from Non-human Primates Naturally Infected with Trypanosoma cruzi Resemble the Major Immunological Findings Observed in Human Chagas Disease

    PubMed Central

    Mattoso-Barbosa, Armanda Moreira; Perdigão-de-Oliveira, Marcelo; Costa, Ronaldo Peres; Elói-Santos, Silvana Maria; Gomes, Matheus de Souza; do Amaral, Laurence Rodrigues; Teixeira-Carvalho, Andréa; Martins-Filho, Olindo Assis; Dick, Edward J.; Hubbard, Gene B.; VandeBerg, Jane F.; VandeBerg, John L.

    2016-01-01

    Background Cynomolgus macaques (Macaca fascicularis) represent a feasible model for research on Chagas disease since natural T. cruzi infection in these primates leads to clinical outcomes similar to those observed in humans. However, it is still unknown whether these clinical similarities are accompanied by equivalent immunological characteristics in the two species. We have performed a detailed immunophenotypic analysis of circulating leukocytes together with systems biology approaches from 15 cynomolgus macaques naturally infected with T. cruzi (CH) presenting the chronic phase of Chagas disease to identify biomarkers that might be useful for clinical investigations. Methods and Findings Our data established that CH displayed increased expression of CD32+ and CD56+ in monocytes and enhanced frequency of NK Granzyme A+ cells as compared to non-infected controls (NI). Moreover, higher expression of CD54 and HLA-DR by T-cells, especially within the CD8+ subset, was the hallmark of CH. A high level of expression of Granzyme A and Perforin underscored the enhanced cytotoxicity-linked pattern of CD8+ T-lymphocytes from CH. Increased frequency of B-cells with up-regulated expression of Fc-γRII was also observed in CH. Complex and imbricate biomarker networks demonstrated that CH showed a shift towards cross-talk among cells of the adaptive immune system. Systems biology analysis further established monocytes and NK-cell phenotypes and the T-cell activation status, along with the Granzyme A expression by CD8+ T-cells, as the most reliable biomarkers of potential use for clinical applications. Conclusions Altogether, these findings demonstrated that the similarities in phenotypic features of circulating leukocytes observed in cynomolgus macaques and humans infected with T. cruzi further supports the use of these monkeys in preclinical toxicology and pharmacology studies applied to development and testing of new drugs for Chagas disease. PMID:26808481

  19. Phenotypic Features of Circulating Leukocytes from Non-human Primates Naturally Infected with Trypanosoma cruzi Resemble the Major Immunological Findings Observed in Human Chagas Disease.

    PubMed

    Sathler-Avelar, Renato; Vitelli-Avelar, Danielle Marquete; Mattoso-Barbosa, Armanda Moreira; Perdigão-de-Oliveira, Marcelo; Costa, Ronaldo Peres; Elói-Santos, Silvana Maria; Gomes, Matheus de Souza; Amaral, Laurence Rodrigues do; Teixeira-Carvalho, Andréa; Martins-Filho, Olindo Assis; Dick, Edward J; Hubbard, Gene B; VandeBerg, Jane F; VandeBerg, John L

    2016-01-01

    Cynomolgus macaques (Macaca fascicularis) represent a feasible model for research on Chagas disease since natural T. cruzi infection in these primates leads to clinical outcomes similar to those observed in humans. However, it is still unknown whether these clinical similarities are accompanied by equivalent immunological characteristics in the two species. We have performed a detailed immunophenotypic analysis of circulating leukocytes together with systems biology approaches from 15 cynomolgus macaques naturally infected with T. cruzi (CH) presenting the chronic phase of Chagas disease to identify biomarkers that might be useful for clinical investigations. Our data established that CH displayed increased expression of CD32+ and CD56+ in monocytes and enhanced frequency of NK Granzyme A+ cells as compared to non-infected controls (NI). Moreover, higher expression of CD54 and HLA-DR by T-cells, especially within the CD8+ subset, was the hallmark of CH. A high level of expression of Granzyme A and Perforin underscored the enhanced cytotoxicity-linked pattern of CD8+ T-lymphocytes from CH. Increased frequency of B-cells with up-regulated expression of Fc-γRII was also observed in CH. Complex and imbricate biomarker networks demonstrated that CH showed a shift towards cross-talk among cells of the adaptive immune system. Systems biology analysis further established monocytes and NK-cell phenotypes and the T-cell activation status, along with the Granzyme A expression by CD8+ T-cells, as the most reliable biomarkers of potential use for clinical applications. Altogether, these findings demonstrated that the similarities in phenotypic features of circulating leukocytes observed in cynomolgus macaques and humans infected with T. cruzi further supports the use of these monkeys in preclinical toxicology and pharmacology studies applied to development and testing of new drugs for Chagas disease.

  20. Winter Cardiovascular Diseases Phenomenon

    PubMed Central

    Fares, Auda

    2013-01-01

    This paper review seasonal patterns across twelve cardiovascular diseases: Deep venous thrombosis, pulmonary embolism, aortic dissection and rupture, stroke, intracerebral hemorrhage, hypertension, heart failure, angina pectoris, myocardial infarction, sudden cardiac death, venricular arrythmia and atrial fibrillation, and discuss a possible cause of the occurrence of these diseases. There is a clear seasonal trend of cardiovascular diseases, with the highest incidence occurring during the colder winter months, which have been described in many countries. This phenomenon likely contributes to the numbers of deaths occurring in winter. The implications of this finding are important for testing the relative importance of the proposed mechanisms. Understanding the influence of season and other factors is essential when seeking to implement effective public health measures. PMID:23724401

  1. The phenomenon of microbial uncultivability.

    PubMed

    Epstein, S S

    2013-10-01

    Most of the microbial diversity on our planet cannot be cultivated, and remains inaccessible. To bring the missing species into culture, microbiologists have introduced over the past decade a number of innovations aiming to meet the demands of new microbes and better mimic their natural conditions. This resulted in a significant increase in microbial recovery yet the real reasons why so many microbes do not grow on artificial media remain largely unknown. The recently proposed scout model of microbial life cycle may provide a partial explanation for the phenomenon. It postulates that transition from dormancy to activity is a stochastic process originating in noise-driven bistability. The model helps explain several otherwise perplexing observations, and informs the future cultivation efforts. Copyright © 2013. Published by Elsevier Ltd.

  2. Phosphene phenomenon: a new concept.

    PubMed

    Bókkon, István

    2008-05-01

    This paper proposes a new biopsychophysical concept of phosphene phenomenon. Namely, visual sensation of phosphenes is due to the intrinsic perception of ultraweak bioluminescent photon emission of cells in the visual system. In other words, phosphenes are bioluminescent biophotons in the visual system induced by various stimuli (mechanical, electrical, magnetic, ionizing radiation, etc.) as well as random bioluminescent biophotons firings of cells in the visual pathway. This biophoton emission can become conscious if induced or spontaneous biophoton emission of cells in the visual system exceeds a distinct threshold. Neuronal biophoton communication can occur by means of non-visual neuronal opsins and natural photosensitive biomolecules. Our interpretation is in direct connection with the functional roles of free radicals and excited biomolecules in living cells.

  3. The neutron channeling phenomenon.

    PubMed

    Khanouchi, A; Sabir, A; Boulkheir, M; Ichaoui, R; Ghassoun, J; Jehouani, A

    1997-01-01

    Shields, used for protection against radiation, are often pierced with vacuum channels for passing cables and other instruments for measurements. The neutron transmission through these shields is an unavoidable phenomenon. In this work we study and discuss the effect of channels on neutron transmission through shields. We consider an infinite homogeneous slab, with a fixed thickness (20 lambda, with lambda the mean free path of the neutron in the slab), which contains a vacuum channel. This slab is irradiated with an infinite source of neutrons on the left side and on the other side (right side) many detectors with windows equal to 2 lambda are placed in order to evaluate the neutron transmission probabilities (Khanouchi, A., Aboubekr, A., Ghassoun, J. and Jehouani, A. (1994) Rencontre Nationale des Jeunes Chercheurs en Physique. Casa Blanca Maroc; Khanouchi, A., Sabir, A., Ghassoun, J. and Jehouani, A. (1995) Premier Congré International des Intéractions Rayonnements Matière. Eljadida Maroc). The neutron history within the slab is simulated by the Monte Carlo method (Booth, T. E. and Hendricks, J. S. (1994) Nuclear Technology 5) and using the exponential biasing technique in order to improve the Monte Carlo calculation (Levitt, L. B. (1968) Nuclear Science and Engineering 31, 500-504; Jehouani, A., Ghassoun, J. and Aboubker, A. (1994) In Proceedings of the 6th International Symposium on Radiation Physics, Rabat, Morocco). Then different geometries of the vacuum channel have been studied. For each geometry we have determined the detector response and calculated the neutron transmission probability for different detector positions. This neutron transmission probability presents a peak for the detectors placed in front of the vacuum channel. This study allowed us to clearly identify the neutron channeling phenomenon. One application of our study is to detect vacuum defects in materials.

  4. Ringing phenomenon of the fiber ring resonator.

    PubMed

    Ying, Diqing; Ma, Huilian; Jin, Zhonghe

    2007-08-01

    A resonator fiber-optic gyro (R-FOG) is a high-accuracy inertial rotation sensor based on the Sagnac effect. A fiber ring resonator is the core sensing element in the R-FOG. When the frequency of the fiber ring resonator input laser is swept linearly with time, ringing of the output resonance curve is observed. The output field of the fiber ring resonator is derived from the superposition of the light transmitted through the directional coupler directly and the multiple light components circulated in the fiber ring resonator when the frequency of the laser is swept. The amplitude and phase of the output field are analyzed, and it is found that the difference in time for different light components in the fiber ring resonator to reach a point of destructive interference causes the ringing phenomenon. Finally the ringing phenomenon is observed in experiments, and the experimental results agree with the theoretical analysis well.

  5. Circulating Natural IgM Antibodies Against Angiogenin in the Peripheral Blood Sera of Patients with Osteosarcoma as Candidate Biomarkers and Reporters of Tumorigenesis

    PubMed Central

    Savitskaya, Yulia A.; Rico, Genaro; Linares, Luis; González, Roberto; Téllez, René; Estrada, Eréndira; Marín, Norma; Martínez, Elisa; Alfaro, Alfonso; Ibarra, Clemente

    2010-01-01

    Background: Tumor immunology research has led to the identification of a number of tumor-associated self antigens, suggesting that most tumors trigger an immunogenic response, as is the case in osteosarcoma, where the detection of natural serum IgM antibodies might achieve the diagnosis of osteosarcoma. Natural IgM antibodies to tumor-associated proteins may expand the number of available tumor biomarkers for osteosarcoma and may be used together in a serum profile to enhance test sensitivity and specificity. Natural IgM antibodies can be consistently detected in the peripheral blood sera months to years before the tumor is diagnosed clinically. The study of the level of a potential biomarker many months (or years) prior to diagnosis is fundamentally important. Integrated circulating and imaging markers in clinical practice treating osteosarcoma have potential applications for controlling tumor angiogenesis. Objectives: To study the expression of natural IgM antibodies to the tumor antigens of angiogenesis in the peripheral blood sera of osteosarcoma patients and healthy individuals, and to develop serum-based predictive biomarkers. Methods: Peripheral venous blood samples were collected from 117 osteosarcoma patients and 117 patients with other tumors. All diagnosis was histologically confirmed. Staging of patients was performed according to the Enneking Surgical Staging System. The control group consisted of 117 age- and sex- matched healthy individuals. In this study, novel immunoconjugates were designed, synthesized and then used to develop a rapid, specific and sensitive enzyme-linked immunosorbent assay (ELISA) method to detect angiogenin (ANG)–IgM directly in the peripheral blood sera of humans. Results: Serum ANG–IgM levels are significantly higher in osteosarcoma patients than in healthy individuals (P < 0.005). Serum ANG–IgM levels varied widely, but were highly dependent on the concentration of IgM (r = 0.85; P < 0.0005). We found ANG–IgM in the

  6. Homocysteine and Raynaud's phenomenon: a review.

    PubMed

    Lazzerini, Pietro Enea; Capecchi, Pier Leopoldo; Bisogno, Stefania; Cozzalupi, Mauro; Rossi, Pier Carlo; Pasini, Franco Laghi

    2010-01-01

    Raynaud's phenomenon, categorized as primary and secondary when occurring isolated or in association with an underlying disease, respectively, is a paroxysmal and recurrent acral ischemia resulting from an abnormal arterial vasospastic response to cold or emotional stress. The key issue in the pathogenesis of Raynaud's phenomenon is presumed to be a dysregulation in the mechanisms of vascular motility resulting in an imbalance between vasodilatation and vasoconstriction. Homocysteine, a non-protein forming sulphured amino acid proposed as an independent risk factor for atherothrombosis in the general population, clearly demonstrated to produce vascular damage through mechanisms also including endothelial injury and modifications in circulating mediators of vasomotion. The rationale for homocysteine involvement in the pathogenesis of Raynaud's phenomenon led some authors to investigate the possible association between mild hyperhomocysteinemia and such a vascular disturbance, particularly in the course of connective tissue disease. Here we review data regarding this putative association and the supposed mechanisms involved, also discussing the emblematic case of a patient with new-onset severe Raynaud's phenomenon and markedly elevated homocysteinemia.

  7. Skewed distribution of circulating activated natural killer T (NKT) cells in patients with common variable immunodeficiency disorders (CVID).

    PubMed

    Carvalho, Karina I; Melo, Karina M; Bruno, Fernanda R; Snyder-Cappione, Jennifer E; Nixon, Douglas F; Costa-Carvalho, Beatriz T; Kallas, Esper G

    2010-09-09

    Common variable immunodeficiency disorder (CVID) is the commonest cause of primary antibody failure in adults and children, and characterized clinically by recurrent bacterial infections and autoimmune manifestations. Several innate immune defects have been described in CVID, but no study has yet investigated the frequency, phenotype or function of the key regulatory cell population, natural killer T (NKT) cells. We measured the frequencies and subsets of NKT cells in patients with CVID and compared these to healthy controls. Our results show a skewing of NKT cell subsets, with CD4+ NKT cells at higher frequencies, and CD8+ NKT cells at lower frequencies. However, these cells were highly activated and expression CD161. The NKT cells had a higher expression of CCR5 and concomitantly expression of CCR5+CD69+CXCR6 suggesting a compensation of the remaining population of NKT cells for rapid effector action.

  8. Experimental Study on Thermal-Hydraulics During Start-Up in the Natural Circulation Boiling Water Reactor Concept: Effects of System Pressure and Increasing Heat Flux on the Geysering and Density Wave Oscillation

    SciTech Connect

    Hadid Subki, M.; Masanori Aritomi; Noriyuki Watanabe; Chaiwat Muncharoen

    2002-07-01

    The feasibility study in thermal-hydraulics for the future light water reactor concept is carried out. One of the essential studies is the two-phase flow instability during start-up in the natural circulation boiling water reactor (BWR) concept. It is anticipated that the occurrence of the two-phase flow instabilities during start-up significantly affects the feasibility concept, since it would cause the complexity in raising and maneuvering the power output. The purpose of the current study is to experimentally investigate the driving mechanism of the geysering and density wave oscillation in the natural circulation loop, induced by a range of system operating pressure and increasing heat flux in vertical parallel channels. The pressure range of atmospheric up to about 4 bars, and the input heat flux range of 0 up to 577 kW/m{sup 2} are applied in these experiments. An experimental apparatus of twin boiling upflow channels to simulate natural circulation flow loop has been designed, constructed and operated. The natural circulation in the loop occurs due to the density difference between two-phase region in the channels and the single-phase liquid in the downcomer. The objective of the study is to propose a rational start-up procedure in which the geysering and density wave oscillation can be prevented during startup, according to its system pressure and heat flux. Previous studies have clarified that three (3) kinds of thermo-hydraulics instabilities may occur during start-up in the natural circulation BWR depending on its procedure and reactor configuration, which are (1) geysering induced by condensation, (2) natural circulation induced by hydrostatic head fluctuation in steam separator, and (3) density wave oscillation. (authors)

  9. Fluorescence: An Interdisciplinary Phenomenon for Different Education Levels

    ERIC Educational Resources Information Center

    García, J. A.; Moreno, J. M.; Perales, F. J.; Romero, J.; Sánchez, P.; Gómez-Robledo, L.

    2012-01-01

    This paper shows the scientific foundations of a natural phenomenon of undoubted interest and applicability in our day, fluorescence, and its possibilities for teaching at three educational levels: primary, secondary and university. It begins by describing the nature of the phenomenon and continues by explaining how we work with students of the…

  10. Coxiella burnetii Circulation in a Naturally Infected Flock of Sheep: Individual Follow-Up of Antibodies in Serum and Milk.

    PubMed

    Joulié, A; Rousset, E; Gasqui, P; Lepetitcolin, E; Leblond, A; Sidi-Boumedine, K; Jourdain, E

    2017-07-01

    The control of Q fever, a zoonotic disease caused by the Coxiella burnetii bacterium, remains a scientific challenge. Domestic ruminants are considered the main reservoir, shedding C. burnetii essentially through parturition products during abortion or birth. Sheep are particularly frequently associated with human outbreaks, but there are insufficient field data to fully understand disease dynamics and to instigate efficient control measures. A longitudinal follow-up study of a naturally infected sheep flock was performed (i) to investigate relationships between seropositivity and bacterial shedding in the vaginal mucus, (ii) to describe the kinetics of antibodies, including responses to vaccination, (iii) to monitor maternal antibodies in ewe lambs, and (iv) to compare serological results for milk and serum samples. For 8 months, we collected blood samples every 3 weeks from 11 aborting and 26 nonaborting dairy ewes, 20 nonaborting suckler ewes, and 9 ewe lambs. Individual milk samples were also obtained from lactating females. All serum and milk samples were tested by enzyme-linked immunosorbent assay (ELISA), whereas vaginal swabs were tested by quantitative PCR. We found that some dairy females did not seroconvert despite shedding C. burnetii in their vaginal mucus. Overall, antibody levels in adult females were found to remain stable over time, with exceptions during the mating and lambing periods. Maternal antibodies decreased during the first month after birth. Interestingly, antibody levels in milk were correlated with those in serum. This study provides valuable field data that will help improve Q fever surveillance and within-flock management measures.IMPORTANCE Field data are necessary to improve the surveillance, diagnosis, and sanitary management of Q fever in livestock. Here, we provide extensive serological data obtained from serum and milk samples from infected and vaccinated ewes belonging to a naturally infected flock of sheep. We show that

  11. Critical Barriers Phenomenon in Elementary Science.

    ERIC Educational Resources Information Center

    Apelman, Maja; And Others

    Conceptual obstacles which inhibit scientific understanding are examined in this monograph. Perspectives are offered on theoretical aspects, research directions, and educational implications on the problem area known as the critical barriers phenomenon. Papers included are: "Nature of the Problem" (by David Hawkins), which describes the…

  12. Critical Barriers Phenomenon in Elementary Science.

    ERIC Educational Resources Information Center

    Apelman, Maja; And Others

    Conceptual obstacles which inhibit scientific understanding are examined in this monograph. Perspectives are offered on theoretical aspects, research directions, and educational implications on the problem area known as the critical barriers phenomenon. Papers included are: "Nature of the Problem" (by David Hawkins), which describes the…

  13. Cozen's phenomenon: a reminder.

    PubMed

    Dorman, S; Jariwala, A; Campbell, D

    2013-08-01

    A four-year-old child attended Accident and Emergency following a fall from a slide with a displaced and angulated proximal tibial metaphyseal fracture. Treatment included closed manipulation under anaesthesia and an above knee cast for seven weeks. Serial radiographs over the following few months were satisfactory demonstrating good alignment and evidence of healing. However, at four-months review new-onset genu valgum with mechanical axis deviation was noted. No evidence of spontaneous resolution was noted over the following 12 months and hence a corrective hemi-epiphysiodesis was performed. At 12-months post-operatively, there was marked clinical and radiographical improvement in alignment. Classically Cozen's phenomenon is described as the late-onset post-traumatic valgus deformity associated with proximal tibial metaphyseal fractures in children. We want to reemphasise the early recognition of children at risk of this unique complication. In addition, we wish to highlight the progression of the late-onset valgus and its subsequent management.

  14. Natural Killer Cell Assessment in Peripheral Circulation and Bronchoalveolar Lavage Fluid of Patients with Severe Sepsis: A Case Control Study

    PubMed Central

    Souza-Fonseca-Guimaraes, Paulo; Guimaraes, Fernando; Natânia De Souza-Araujo, Caroline; Maria Boldrini Leite, Lidiane; Cristina Senegaglia, Alexandra; Nishiyama, Anita; Souza-Fonseca-Guimaraes, Fernando

    2017-01-01

    Sepsis is a complex systemic inflammatory syndrome, the most common cause of which is attributed to systemic underlying bacterial infection. The complete mechanisms of the dynamic pro- and anti-inflammatory processes underlying the pathophysiology of sepsis remain poorly understood. Natural killer (NK) cells play a crucial role in the pathophysiology of sepsis, leading to exaggerated inflammation due their rapid response and production of pro-inflammatory cytokines such as interferon gamma (IFN-γ). Several studies have already shown that NK cells undergo lymphopenia in the peripheral blood of patients with sepsis. However, our understanding of the mechanisms behind its cellular trafficking and its role in disease development is restricted to studies in animal models. In this study, we aimed to compare the human NK cell subset (CD56bright or dim) levels in the peripheral blood and bronchoalveolar lavage (BAL) fluid of sepsis patients. We conducted a case-control study with a sample size consisting of 10 control patients and 23 sepsis patients enrolled at the Hospital Cajuru (Curitiba/PR, Brazil) from 2013 to 2015. Although we were able to confirm previous observations of peripheral blood lymphopenia, no significant differences were detected in NK cell levels in the BAL fluid of these patients. Overall, these findings strengthened the evidence that peripheral blood lymphopenia is likely to be associated with cell death as a consequence of sepsis. PMID:28287491

  15. Natural Killer Cell Assessment in Peripheral Circulation and Bronchoalveolar Lavage Fluid of Patients with Severe Sepsis: A Case Control Study.

    PubMed

    Souza-Fonseca-Guimaraes, Paulo; Guimaraes, Fernando; Natânia De Souza-Araujo, Caroline; Maria Boldrini Leite, Lidiane; Cristina Senegaglia, Alexandra; Nishiyama, Anita; Souza-Fonseca-Guimaraes, Fernando

    2017-03-12

    Sepsis is a complex systemic inflammatory syndrome, the most common cause of which is attributed to systemic underlying bacterial infection. The complete mechanisms of the dynamic pro- and anti-inflammatory processes underlying the pathophysiology of sepsis remain poorly understood. Natural killer (NK) cells play a crucial role in the pathophysiology of sepsis, leading to exaggerated inflammation due their rapid response and production of pro-inflammatory cytokines such as interferon gamma (IFN-γ). Several studies have already shown that NK cells undergo lymphopenia in the peripheral blood of patients with sepsis. However, our understanding of the mechanisms behind its cellular trafficking and its role in disease development is restricted to studies in animal models. In this study, we aimed to compare the human NK cell subset (CD56(bright or dim)) levels in the peripheral blood and bronchoalveolar lavage (BAL) fluid of sepsis patients. We conducted a case-control study with a sample size consisting of 10 control patients and 23 sepsis patients enrolled at the Hospital Cajuru (Curitiba/PR, Brazil) from 2013 to 2015. Although we were able to confirm previous observations of peripheral blood lymphopenia, no significant differences were detected in NK cell levels in the BAL fluid of these patients. Overall, these findings strengthened the evidence that peripheral blood lymphopenia is likely to be associated with cell death as a consequence of sepsis.

  16. Mucocutaneous Splendore-Hoeppli phenomenon.

    PubMed

    Hussein, Mahmoud R

    2008-11-01

    Splendore-Hoeppli phenomenon (asteroid bodies) is the in vivo formation of intensely eosinophilic material (radiate, star-like, asteroid or club-shaped configurations) around microorganisms (fungi, bacteria and parasites) or biologically inert substances. This study presents a literature review concerning Splendore-Hoeppli reaction in the mucocutaneous diseases. It examines the histopathological features, nature and differential diagnosis of this reaction. It also discusses the mucocutaneous infections and the non-infective diseases associated with it. Available studies indicate that several mucocutaneous infections can generate Splendore-Hoeppli reaction. The fungal infections include sporotrichosis, pityrosporum folliculitis, zygomycosis, candidiasis, aspergillosis and blastomycosis. The bacterial infections include botryomycosis, nocardiosis and actinomycosis. The parasitic conditions include orbital pythiosis, strongyloidiasis, schistosomiasis and cutaneous larva migrans. In addition, Splendore-Hoeppli reaction may be seen with non-infective pathology such as hypereosinophilic syndrome and allergic conjunctival granulomas. The Splendore-Hoeppli reaction material comprises antigen-antibody complex, tissue debris and fibrin. Although the exact nature of this reaction is unknown, it is thought to be a localized immunological response to an antigen-antibody precipitate related to fungi, parasites, bacteria or inert materials. The characteristic formation of the peribacterial or perifungal Splendore-Hoeppli reaction probably prevents phagocytosis and intracellular killing of the insulting agent leading to chronicity of infection. To conclude, Splendore-Hoeppli reaction is a tell tale of a spectrum of infections and reactive conditions. The molecular pathways involved in the development of this reaction are open for future investigations.

  17. [Phenomenon of dental fear].

    PubMed

    Moore, R; Birn, H

    1990-01-01

    Odontophobia is a rather unique phobia with special psychosomatic components that impact on the dental health of odontophobic persons. It also has psychosocial components largely as a result of destruction of the teeth and subsequent embarrassment that can affect a person and cause a vicious cycle of dental fear. The phenomenon is facilitated by misunderstandings and myths generated by both patients and dentists. The most common reasons given in the literature for such strong fears of dental treatment are: 1) bad experiences in childhood for 85% of cases, 2) feeling of powerlessness and lack of control over personal emotional reactions and over the social situation in the dental chair, 3) social learning processes in which the image of the dentist is cast in a negative light by the mass media or by the person's relatives or friends and 4) that the person has other psychologic problems (in 20% of cases), such as serious phobias and/or neuroses. A strategy of researching and thus tackling the problem is presented which focuses on three essential targets that require studying and change: 1) the community at large and their image of the dentist, 2) the patient role and 3) the dentist role. Various model projects are presented along with their diagnostic systems. These are seen to focus in varying degrees on different elements of the target groups that effect the dentist-patient relationship but the need to come out into the community and make the social environment right for these patients is an important factor in all strategies.(ABSTRACT TRUNCATED AT 250 WORDS)

  18. The chlorophyll a fluorescence induction curve in the green microalga Haematococcus pluvialis: further insight into the nature of the P-S-M fluctuation and its relationship with the "low-wave" phenomenon at steady-state.

    PubMed

    Fratamico, Anthony; Tocquin, Pierre; Franck, Fabrice

    2016-06-01

    Chlorophyll fluorescence is an information-rich signal which provides an access to the management of light absorbed by PSII. A good example of this is the succession of fast fluorescence fluctuations during light-induced photosynthetic induction after dark-adaptation. During this period, the fluorescence trace exhibits several inflexion points: O-J-I-P-S-M-T. Whereas the OJIP part of this kinetics has been the subject of many studies, the processes that underly the PSMT transient are less understood. Here, we report an analysis of the PSMT phase in the green microalga Haematococcus pluvialis in terms of electron acceptors and light use by photochemistry, fluorescence and non-photochemical quenching (NPQ). We identify additional sub-phases between P and S delimited by an inflexion point, that we name Q, found in the second time scale. The P-Q phase expresses a transient photochemical quenching specifically due to alternative electron transport to oxygen. During the transition from Q to S, the NPQ increases and then relaxes during the S-M phase in about 1 min. It is suggested that this transient NPQ observed during induction is a high energy state quenching (qE) dependent on the alternative electron transport to molecular oxygen. We further show that this NPQ is of the same nature than the NPQ, known as the low-wave phenomenon, which is transiently observed after a saturating light pulse given at steady-state. In both cases, the NPQ is oxygen-dependent. This NPQ is observed at external pH 6.0, but not at pH 7.5, which seems correlated with faster saturation of the PQ pool at pH 6.0.

  19. Development of a plant dynamics computer code for analysis of a supercritical carbon dioxide Brayton cycle energy converter coupled to a natural circulation lead-cooled fast reactor.

    SciTech Connect

    Moisseytsev, A.; Sienicki, J. J.

    2007-03-08

    STAR-LM is a lead-cooled pool-type fast reactor concept operating under natural circulation of the coolant. The reactor core power is 400 MWt. The open-lattice core consists of fuel pins attached to the core support plate, (the does not consist of removable fuel assemblies). The coolant flows outside of the fuel pins. The fuel is transuranic nitride, fabricated from reprocessed LWR spent fuel. The cladding material is HT-9 stainless steel; the steady-state peak cladding temperature is 650 C. The coolant is single-phase liquid lead under atmospheric pressure; the core inlet and outlet temperatures are 438 C and 578 C, respectively. (The Pb coolant freezing and boiling temperatures are 327 C and 1749 C, respectively). The coolant is contained inside of a reactor vessel. The vessel material is Type 316 stainless steel. The reactor is autonomous meaning that the reactor power is self-regulated based on inherent reactivity feedbacks and no external power control (through control rods) is utilized. The shutdown (scram) control rods are used for startup and shutdown and to stop the fission reaction in case of an emergency. The heat from the reactor is transferred to the S-CO{sub 2} Brayton cycle in in-reactor heat exchangers (IRHX) located inside the reactor vessel. The IRHXs are shell-and-tube type heat exchangers with lead flowing downwards on the shell side and CO{sub 2} flowing upwards on the tube side. No intermediate circuit is utilized. The guard vessel surrounds the reactor vessel to contain the coolant, in the very unlikely event of reactor vessel failure. The Reactor Vessel Auxiliary Cooling System (RVACS) implementing the natural circulation of air flowing upwards over the guard vessel is used to cool the reactor, in the case of loss of normal heat removal through the IRHXs. The RVACS is always in operation. The gap between the vessels is filled with liquid lead-bismuth eutectic (LBE) to enhance the heat removal by air by significantly reducing the thermal

  20. Possible dynamical mechanisms for the Martian polar warming phenomenon

    NASA Technical Reports Server (NTRS)

    Barnes, Jeffrey R.

    1987-01-01

    The research performed under NASA contract NAGW-727 falls into three major categories, i.e., dynamical modeling of the Martian polar warming phenomenon, studies of dust and water transport associated with a Martian polar warming, and studies of the possible effects of breaking gravity waves on the Martian atmospheric circulation. The work carried out in each of these areas is summarized.

  1. Successful Antiparasitic Treatment for Cysticercosis is Associated with a Fast and Marked Reduction of Circulating Antigen Levels in a Naturally Infected Pig Model.

    PubMed

    Gonzalez, Armando E; Bustos, Javier A; Garcia, Hector H; Rodriguez, Silvia; Zimic, Mirko; Castillo, Yesenia; Praet, Nicolas; Gabriël, Sarah; Gilman, Robert H; Dorny, Pierre

    2015-12-01

    Taenia solium cysticercosis is a common parasitic infection of humans and pigs. We evaluated the posttreatment evolution of circulating parasite-specific antigen titers in 693 consecutive blood samples from 50 naturally infected cysticercotic pigs, which received different regimes of antiparasitic drugs (N = 39, 7 groups), prednisone (N = 5), or controls (N = 6). Samples were collected from baseline to week 10 after treatment, when pigs were euthanized and carefully dissected at necropsy. Antigen levels decreased proportionally to the efficacy of treatment and correlated with the remaining viable cysts at necropsy (Pearson's p = 0.67, P = 0.000). A decrease of 5 times in antigen levels (logarithmic scale) compared with baseline was found in 20/26 pigs free of cysts at necropsy, compared with 1/24 of those who had persisting viable cysts (odds ratio [OR] = 76.7, 95% confidence interval [CI] = 8.1-3308.6, P < 0.001). Antigen monitoring reflects the course of infection in the pig. If a similar correlation exists in infected humans, this assay may provide a minimally invasive and easy monitoring assay to assess disease evolution and efficacy of antiparasitic treatment in human neurocysticercosis.

  2. Successful Antiparasitic Treatment for Cysticercosis Is Associated with a Fast and Marked Reduction of Circulating Antigen Levels in a Naturally Infected Pig Model

    PubMed Central

    Gonzalez, Armando E.; Bustos, Javier A.; Garcia, Hector H.; Rodriguez, Silvia; Zimic, Mirko; Castillo, Yesenia; Praet, Nicolas; Gabriël, Sarah; Gilman, Robert H.

    2015-01-01

    Taenia solium cysticercosis is a common parasitic infection of humans and pigs. We evaluated the posttreatment evolution of circulating parasite-specific antigen titers in 693 consecutive blood samples from 50 naturally infected cysticercotic pigs, which received different regimes of antiparasitic drugs (N = 39, 7 groups), prednisone (N = 5), or controls (N = 6). Samples were collected from baseline to week 10 after treatment, when pigs were euthanized and carefully dissected at necropsy. Antigen levels decreased proportionally to the efficacy of treatment and correlated with the remaining viable cysts at necropsy (Pearson's p = 0.67, P = 0.000). A decrease of 5 times in antigen levels (logarithmic scale) compared with baseline was found in 20/26 pigs free of cysts at necropsy, compared with 1/24 of those who had persisting viable cysts (odds ratio [OR] = 76.7, 95% confidence interval [CI] = 8.1–3308.6, P < 0.001). Antigen monitoring reflects the course of infection in the pig. If a similar correlation exists in infected humans, this assay may provide a minimally invasive and easy monitoring assay to assess disease evolution and efficacy of antiparasitic treatment in human neurocysticercosis. PMID:26392159

  3. Paradigm Shift in Dendritic Cell-Based Immunotherapy: From in vitro Generated Monocyte-Derived DCs to Naturally Circulating DC Subsets

    PubMed Central

    Wimmers, Florian; Schreibelt, Gerty; Sköld, Annette E.; Figdor, Carl G.; De Vries, I. Jolanda M.

    2014-01-01

    Dendritic cell (DC)-based immunotherapy employs the patients’ immune system to fight neoplastic lesions spread over the entire body. This makes it an important therapy option for patients suffering from metastatic melanoma, which is often resistant to chemotherapy. However, conventional cellular vaccination approaches, based on monocyte-derived DCs (moDCs), only achieved modest response rates despite continued optimization of various vaccination parameters. In addition, the generation of moDCs requires extensive ex vivo culturing conceivably hampering the immunogenicity of the vaccine. Recent studies, thus, focused on vaccines that make use of primary DCs. Though rare in the blood, these naturally circulating DCs can be readily isolated and activated thereby circumventing lengthy ex vivo culture periods. The first clinical trials not only showed increased survival rates but also the induction of diversified anti-cancer immune responses. Upcoming treatment paradigms aim to include several primary DC subsets in a single vaccine as pre-clinical studies identified synergistic effects between various antigen-presenting cells. PMID:24782868

  4. [Raynaud's phenomenon: pathogenesis and prevalence].

    PubMed

    Mikulska, Danuta

    2010-01-01

    Raynaud's phenomenon is defined as occasional ischemia of the distal parts of the extremities. Ischemia may be idiopathic as in primary Raynaud's disease or instigated by a comorbidity as in Raynaud's syndrome. Opinions on the etiopathogenesis of Raynaud's phenomenon have changed during recent years. Research has shown that enhanced vascular reactivity is attributable more to local factors and less to abnormalities in the central nervous system. Local factors are classified as vascular, nervous, and intravascular. Changes in our understanding of the etiopathogenesis of Raynaud's phenomenon have resulted in modified therapeutic guidelines. The present work reviews current opinions on the etiopathogenesis of Raynaud's phenomenon.

  5. The phenomenon of famine.

    PubMed

    Scrimshaw, N S

    1987-01-01

    Famines are sustained, extreme shortages of food among discrete populations sufficient to cause high rates of mortality. Signs and symptoms of prolonged food deprivation include loss of fat and subcutaneous tissue, depression, apathy, and weakness, which progress to immobility and death of the individual, often from superimposed respiratory or other infections. The social consequences of famines are disruption from mass migrations of people in search of food, breakdown of social behavior, abandonment of cooperative effort, loss of personal pride and sense of family ties, and finally a struggle for individual survival. Famines have been common ever since the development of agriculture made human settlements possible. Food shortages due to crop failures caused by natural disasters including poor weather, insect plagues, and plant diseases; crop destruction due to warfare; and enforced starvation as a political tool are by no means the only causative factors. Many of the worst famines have been due to poor distribution of existing food supplies, either because of inequities that result in a lack of purchasing power on the part of the poor or because of political interference with normal distribution or relief movements of food. Europe and Asia, which in the past experienced frequent severe famines, sometimes with deaths in the hundreds of thousands or millions, have now largely eliminated famines through social and technological change. However, in Africa, political and social factors have destroyed the capacity of many populations to survive drought-induced variations in local food supplies and prices. Thus, famines are due to varying combinations of inadequacy of food supplies for whatever reason and the inability of populations to acquire food because of poverty, civil disturbances, or political interference. Despite the role of natural causes, the conclusion is inescapable that modern famines, like most of those in history, are man-made.

  6. The enrichment of natural radionuclides in oil shale-fired power plants in Estonia--the impact of new circulating fluidized bed technology.

    PubMed

    Vaasma, Taavi; Kiisk, Madis; Meriste, Tõnis; Tkaczyk, Alan Henry

    2014-03-01

    Burning oil shale to produce electricity has a dominant position in Estonia's energy sector. Around 90% of the overall electric energy production originates from the Narva Power Plants. The technology in use has been significantly renovated - two older types of pulverized fuel burning (PF) energy production units were replaced with new circulating fluidized bed (CFB) technology. Additional filter systems have been added to PF boilers to reduce emissions. Oil shale contains various amounts of natural radionuclides. These radionuclides concentrate and become enriched in different boiler ash fractions. More volatile isotopes will be partially emitted to the atmosphere via flue gases and fly ash. To our knowledge, there has been no previous study for CFB boiler systems on natural radionuclide enrichment and their atmospheric emissions. Ash samples were collected from Eesti Power Plant's CFB boiler. These samples were processed and analyzed with gamma spectrometry. Activity concentrations (Bq/kg) and enrichment factors were calculated for the (238)U ((238)U, (226)Ra, (210)Pb) and (232)Th ((232)Th, (228)Ra) family radionuclides and for (40)K in different CFB boiler ash fractions. Results from the CFB boiler ash sample analysis showed an increase in the activity concentrations and enrichment factors (up to 4.5) from the furnace toward the electrostatic precipitator block. The volatile radionuclide ((210)Pb and (40)K) activity concentrations in CFB boilers were evenly distributed in finer ash fractions. Activity balance calculations showed discrepancies between input (via oil shale) and output (via ash fractions) activities for some radionuclides ((238)U, (226)Ra, (210)Pb). This refers to a situation where the missing part of the activity (around 20% for these radionuclides) is emitted to the atmosphere. Also different behavior patterns were detected for the two Ra isotopes, (226)Ra and (228)Ra. A part of (226)Ra input activity, unlike (228)Ra, was undetectable in the

  7. Raynaud's phenomenon induced by sulphasalazine.

    PubMed Central

    Reid, J.; Holt, S.; Housley, E.; Sneddon, D. J.

    1980-01-01

    Sulphasalazine-induced Raynaud's phenomenon is reported in a patient who showed no other features of a drug-induced lupus syndrome. The vascular disturbance disappeared when the drug was withdrawn on 3 occasions. A simple technique for assessing the circulatory abnormality in Raynaud's phenomenon is described. PMID:6104805

  8. The cutoff phenomenon in finite Markov chains.

    PubMed Central

    Diaconis, P

    1996-01-01

    Natural mixing processes modeled by Markov chains often show a sharp cutoff in their convergence to long-time behavior. This paper presents problems where the cutoff can be proved (card shuffling, the Ehrenfests' urn). It shows that chains with polynomial growth (drunkard's walk) do not show cutoffs. The best general understanding of such cutoffs (high multiplicity of second eigenvalues due to symmetry) is explored. Examples are given where the symmetry is broken but the cutoff phenomenon persists. PMID:11607633

  9. Regulatory role of membrane-bound form interleukin-15 on human uterine microvascular endothelial cells in circulating CD16(-) natural killer cell extravasation into human endometrium.

    PubMed

    Kitaya, Kotaro; Yasuo, Tadahiro

    2013-09-01

    Interleukin (IL)-15 plays a major role in accumulation of unique CD16(-) natural killer (NK) cells in the human endometrium, partly via selective extravasation of peripheral blood (PB) counterparts from local microvascular circulation. While IL-15 exhibits a chemotactic activity for PB CD16(-) NK cells, IL-15 attenuates their binding capacity to dermatan sulfate, the major CD62L ligand expressed on human uterine microvascular endothelial cells (HUtMVECs). These findings suggest that premature action of IL-15 interferes with CD62L-dependent tethering/rolling of PB CD16(-) NK cells on HUtMVECs, which is an early critical process of leukocyte extravasation. In this study, we investigated the mechanisms underlying the IL-15 regulation in the initial CD62L-dependent contact between PB CD16(-) NK cells and HUtMVECs. Unlike other candidate molecules, recombinant IL-15 downregulated CD62L expression on freshly isolated PB CD16(-) NK cells. IL-12 and IL-10, the two known upregulators of CD62L on CD16(-) NK cells, were not detectable in HUtMVECs and endometrial perivascular stromal cells. Binding to immobilized dermatan sulfate increased surface IL-15 receptor-alpha chain expression on CD16(-) NK cells. Under ovarian steroid stimulation, IL-15 was detectable on the surface, but not in the supernatant, of cultured HUtMVECs. Ovarian steroid-induced IL-15 expression on HUtMVECs was not attenuated by chondroitinase ABC (which degrades chondroitin sulfate-A and -C and dermatan sulfate) or sodium acetate buffer (which dissociates cytokines from their cognate receptors). These results suggest that HUtMVECs secrete a less soluble form of IL-15 into local microcirculation. Instead, HUtMVECs bear a membrane-bound form IL-15 under the influence of ovarian steroids, which may be favorable for preventing downregulation of CD62L on PB CD16(-) NK cells and facilitating their initial contact with HUtMVECs.

  10. Theory of the shimmy phenomenon

    NASA Astrophysics Data System (ADS)

    Zhuravlev, V. Ph.; Klimov, D. M.

    2010-06-01

    The shimmy phenomenon is the appearance of angular self-excited vibrations of the carriage wheels. Such self-excited vibrations provide a serious safety hazard for motion, which explains the great interest of scientists in this phenomenon [1-6]. This problem is most serious for the aircraft fore wheels. It is commonly agreed that themain cause of the shimmyphenomenon is the tyre deformation [2]. We do not doubt this thesis, but still we note that this cause is not unique. The shimmy phenomenon can be observed in everyday life in the case of various hand trucks with rigid wheels, where the reference to the elastic tyre is out of place. In what follows, we show that the theory of polycomponent dry friction can completely explain the shimmy phenomenon for absolutely rigid wheels, and hence can be at least one of the causes of this phenomenon in the general case. Dry friction has been ignored by the scientists in their explanations of the shimmy phenomenon, because this friction has not been fully investigated until now, and it has been impossible to explain the shimmy phenomenon in the framework of the former representations.

  11. Differential pathogenesis of lethal mousepox in congenic DBA/2 mice implicates natural killer cell receptor NKR-P1 in necrotizing hepatitis and the fifth component of complement in recruitment of circulating leukocytes to spleen.

    PubMed

    Brownstein, D G; Gras, L

    1997-04-01

    Innate resistance of C57BL/6 (B6) mice to lethal mousepox is controlled by multiple genes. Previously, four resistance genes were localized to specific subchromosomal regions and transferred onto a susceptible DBA/2 (D2) background by serial backcrossing and intercrossing to produce congenic strains. Intraperitoneally inoculated ectromelia virus was uniformly lethal and achieved similar titers in B6 and D2 mice but elicited differential responses in liver, spleen, and circulating blood leukocytes. The distribution of these response phenotypes in congenic strains linked control of phenotypes with specific subchromosomal regions. D2.R1 mice, which carried a differential segment of chromosome 6, exhibited a B6 liver response and intermediate spleen and circulating leukocyte responses. D2.R2 and D2.R4 mice, which carried differential segments of chromosomes 2 and 1, respectively, exhibited a D2 liver response, a B6 spleen response, and an intermediate circulating leukocyte response. The localization of control of liver response phenotypes to chromosome 6 implicates cells that express natural killer (NK) cell receptor NKR-P1 alloantigens. The localization of control of spleen and circulating leukocyte responses to chromosomes 1, 2, and 6 implicates NK cells, the fifth component of complement, and a gene near the selectin gene complex in recruitment of circulating leukocytes to spleen.

  12. [Raynaud's phenomenon, disease or syndrome?].

    PubMed

    Fiessinger, Jean-Noël

    2011-09-01

    Raynaud's phenomenon is a common symptom. More often it is usually an idiopathic and benign condition. But it can be an early manifestation of a connective tissue disease especially scleroderma and primary Sjogren's syndrom. Thus it is necessary to develop reasonable screening model. If the vasomotor symptoms are localized, a diagnosis of secondary Raynaud's phenomenon is highly probable and the main etiology is an arterial disease. Occupational arterial lesions are a particularly aspect of secondary Raynaud's phenomenon. Calcium channel blockers are the reference for the symptomatic treatment of Raynaud's phenomenon. In severe secondary forms, intravenous iloprost infusion is effective. New drugs as endothelin antagonist and phospodiesterase type 5 inhibitors are still to be evaluated.

  13. [Methylphenidate and secondary Raynaud's phenomenon].

    PubMed

    Iglesias Otero, M; Portela Romero, M; Bugarín González, R; Ventura Victoria, M A

    2013-09-01

    Raynaud's phenomenon is a clinical disease characterized by episodic attacks of vasoconstriction of the arteries and arterioles of the extremities such as fingers and toes, sometimes the ears and nose, in response to cold or emotional stimuli. A classic attack is the pallor of the distal extremity, followed by cyanosis and redness, accompanied by paresthesia, usually as heat. When it occurs without apparent cause is called primary Raynaud's phenomenon. When associated with other disease, is called secondary Raynaud's phenomenon. The secondary table is associated with increased frequency of rheumatic diseases of collagen. They can also present certain drugs that cause vasoconstriction, such as ergotamine, beta-adrenergic antagonists, contraception and sympathomimetic drugs. Regarding the latter, we present a case of Raynaud's phenomenon secondary to methylphenidate in a 14 years.

  14. Treatment with the natural FXR agonist chenodeoxycholic acid reduces clearance of plasma LDL whilst decreasing circulating PCSK9, lipoprotein(a) and apolipoprotein C-III.

    PubMed

    Ghosh Laskar, M; Eriksson, M; Rudling, M; Angelin, B

    2017-06-01

    The natural farnesoid X receptor (FXR) agonist chenodeoxycholic acid (CDCA) suppresses hepatic cholesterol and bile acid synthesis and reduces biliary cholesterol secretion and triglyceride production. Animal studies have shown that bile acids downregulate hepatic LDL receptors (LDLRs); however, information on LDL metabolism in humans is limited. Kinetics of autologous (125) I-LDL were determined in 12 male subjects at baseline and during treatment with CDCA (15 mg kg(-1) day(-1) ). In seven patients with gallstones treated with CDCA for 3 weeks before cholecystectomy, liver biopsies were collected and analysed for enzyme activities and for specific LDLR binding. Serum samples obtained before treatment and at surgery were analysed for markers of lipid metabolism, lipoproteins and the LDLR modulator proprotein convertase subtilisin/kexin type 9 (PCSK9). Chenodeoxycholic acid treatment increased plasma LDL cholesterol by ~10% as a result of reduced clearance of plasma LDL-apolipoprotein (apo)B; LDL production was somewhat reduced. The reduction in LDL clearance occurred within 1 day after initiation of treatment. In CDCA-treated patients with gallstones, hepatic microsomal cholesterol 7α-hydroxylase and HMG-CoA reductase activities were reduced by 83% and 54%, respectively, and specific LDLR binding was reduced by 20%. During treatment, serum levels of fibroblast growth factor 19 and total and LDL cholesterol increased, whereas levels of 7α-hydroxy-4-cholesten-3-one, lathosterol, PCSK9, apoA-I, apoC-III, lipoprotein(a), triglycerides and insulin were reduced. Chenodeoxycholic acid has a broad influence on lipid metabolism, including reducing plasma clearance of LDL. The reduction in circulating PCSK9 may dampen its effect on hepatic LDLRs and plasma LDL cholesterol. Further studies of the effects of other FXR agonists on cholesterol metabolism in humans seem warranted, considering the renewed interest for such therapy in liver disease and diabetes. © 2017 The

  15. Diffusion phenomenon in Hilbert spaces and applications

    NASA Astrophysics Data System (ADS)

    Radu, Petronela; Todorova, Grozdena; Yordanov, Borislav

    2011-06-01

    We prove an abstract version of the striking diffusion phenomenon that offers a strong connection between the asymptotic behavior of abstract parabolic and dissipative hyperbolic equations. An important aspect of our approach is that we use in a natural way spectral analysis without involving complicated resolvent estimates. Our proof of the diffusion phenomenon does not use the individual behavior of solutions; instead we show that only their difference matters. We estimate the Hilbert norm of the difference in terms of the Hilbert norm of solutions to the parabolic problems, which allows us to transfer the decay from the parabolic to the hyperbolic problem. The application of these estimates to operators with Markov property combined with a weighted Nash inequality yields explicit and sharp decay rates for hyperbolic problems with variable (x-dependent) coefficients in exterior domains. Our method provides new insight in this area of extensive research which was not well understood until now.

  16. Pink tooth phenomenon: an enigma?

    PubMed

    Thapar, Raveena; Choudhry, Swati; Sinha, Anju; Bali, Ruchita; Shukla, Deepika

    2013-10-01

    The appearance of pink teeth is a common phenomenon which has been observed after death in certain circumstances on post-mortem examination. Extra fibrinolytic activity of pulp facilitates rapid breakdown of red blood cells and diffusion of hemoglobin and its derivatives to flow into dentine. We reviewed various studies on pink tooth phenomenon which have stated the various factors that lead to pink tooth formation. Most of the authors have stressed that post-mortem pink teeth must not be considered as a reliable odontological parameter for determining cause of death. No correlation has been found between the occurrence of pink teeth and the cause of death but condition of the surroundings certainly plays an important role in the development of this phenomenon. This paper reviews the factors and conditions responsible for formation of pink teeth. Copyright © 2013 Elsevier Ltd and Faculty of Forensic and Legal Medicine. All rights reserved.

  17. Translation as a Psycholinguistic Phenomenon

    ERIC Educational Resources Information Center

    Zasyekin, Serhiy

    2010-01-01

    The article sketches the outlines of a theoretical framework for the analysis of translation of literary texts, viewed as psycho-semiotic phenomenon and based on evaluation of earlier attempts in this direction, and on the results of a psycholinguistic empirical study of translations. Central to this framework is the recent insight that the human…

  18. Translation as a Psycholinguistic Phenomenon

    ERIC Educational Resources Information Center

    Zasyekin, Serhiy

    2010-01-01

    The article sketches the outlines of a theoretical framework for the analysis of translation of literary texts, viewed as psycho-semiotic phenomenon and based on evaluation of earlier attempts in this direction, and on the results of a psycholinguistic empirical study of translations. Central to this framework is the recent insight that the human…

  19. The Tullio phenomenon: a neurologically neglected presentation.

    PubMed

    Kaski, Diego; Davies, R; Luxon, L; Bronstein, A M; Rudge, P

    2012-01-01

    The Tullio phenomenon refers to sound-induced disequilibrium or oscillopsia. Patients with this condition frequently present to neurologists, many of whom are unfamiliar with the condition and its diagnostic criteria. Indeed, due to the unusual nature of the symptoms patients are often misdiagnosed as having psychiatric disturbances. Tullio patients describe disequilibrium, auditory and visual symptoms, which are recurrent, brief, and often triggered by loud noises or middle ear pressure changes, e.g. the Valsalva manoeuvre. Many cases are associated with superior semicircular canal dehiscence (SCCD). Early work suggested that the presence of sound-induced torsional eye movements and visual field tilts were consequent upon a utricular-mediated ocular tilt reaction. However, more recent evidence from imaging and oculographic research, as well as data from our patient series indicates that these ocular abnormalities are usually the result of superior semicircular canal stimulation. The clinical history and a focussed examination are often sufficient to make the diagnosis, which can be confirmed with high resolution CT imaging of the temporal bones. In some patients, surgical occlusion or resurfacing of the affected canal can ameliorate symptoms and signs. The aim of this paper is two-fold: Firstly, to review the clinical features of the Tullio phenomenon, and secondly, to highlight our own observations in three cases with a new clinical syndrome consisting of Tullio's phenomenon with bilateral vestibular failure, a pure horizontal nystagmus in response to sound, and no evidence of canal dehiscence.

  20. TROPICAL METEOROLOGY & Climate: Hadley Circulation

    SciTech Connect

    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.

  1. Wellness as a worldwide phenomenon?

    PubMed

    Elliott, Heather; Bernstein, Jennifer; Bowman, Diana M

    2014-10-01

    This article examines the concept of wellness through a comparative political economy and legal framework. It asks whether wellness, an increasingly defined term within US federal and state legislative instruments including, for example, the Patient Protection and Affordable Care Act, is primarily a US-centric phenomenon. Or is wellness, in its various different guises, a worldwide phenomenon? By focusing on three distinctly different jurisdictions - the United States, Germany, and Australia - this article examines wellness through the lens of employers, the health care system, employment and tort law, and the greater political economy. It notes that while improving employee health, well-being, and productivity is common across the three countries and their respective cultures, the focus on wellness as a distinct legal concept is unique to the United States. Copyright © 2014 by Duke University Press.

  2. STUDIES ON THE SHWARTZMAN PHENOMENON

    PubMed Central

    Klein, Herbert M.

    1932-01-01

    Formalin induces a considerable change in meningococcus culture filtrates. This consists of a marked decrease in toxidty as concerns both the Shwartzman phenomenon and the lethal effect, with relative preservation of the antibody-combining capacity and antigenicity. A similar modification occurs spontaneously in meningococcus culture filtrates on standing. Inasmuch as these changes parallel those occurring in the conversion of diphtheria toxin into toxoid, it is justifiable to consider such altered meningococcus toxin as meningococcus toxoid. PMID:19870087

  3. Lower numbers of circulating natural killer T (NK T) cells in individuals with human T lymphotropic virus type 1 (HTLV-1) associated neurological disease

    PubMed Central

    Ndhlovu, L C; Snyder-Cappione, J E; Carvalho, K I; Leal, F E; Loo, C P; bruno, F R; Jha, A R; Devita, D; Hasenkrug, A M; Barbosa, H M R; Segurado, A C; Nixon, D F; Murphy, E L; Kallas, E G

    2009-01-01

    Human T lymphotropic virus type 1 (HTLV-1) infects 10–20 million people worldwide. The majority of infected individuals are asymptomatic; however, approximately 3% develop the debilitating neurological disease HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP). There is also currently no cure, vaccine or effective therapy for HTLV-1 infection, and the mechanisms for progression to HAM/TSP remain unclear. NK T cells are an immunoregulatory T cell subset whose frequencies and effector functions are associated critically with immunity against infectious diseases. We hypothesized that NK T cells are associated with HAM/TSP progression. We measured NK T cell frequencies and absolute numbers in individuals with HAM/TSP infection from two cohorts on two continents: São Paulo, Brazil and San Francisco, CA, USA, and found significantly lower levels when compared with healthy subjects and/or asymptomatic carriers. Also, the circulating NK T cell compartment in HAM/TSP subjects is comprised of significantly more CD4+ and fewer CD8+ cells than healthy controls. These findings suggest that lower numbers of circulating NK T cells and enrichment of the CD4+ NK T subset are associated with HTLV-1 disease progression. PMID:19778295

  4. Water condensation: a multiscale phenomenon.

    PubMed

    Jensen, Kasper Risgaard; Fojan, Peter; Jensen, Rasmus Lund; Gurevich, Leonid

    2014-02-01

    The condensation of water is a phenomenon occurring in multiple situations in everyday life, e.g., when fog is formed or when dew forms on the grass or on windows. This means that this phenomenon plays an important role within the different fields of science including meteorology, building physics, and chemistry. In this review we address condensation models and simulations with the main focus on heterogeneous condensation of water. The condensation process is, at first, described from a thermodynamic viewpoint where the nucleation step is described by the classical nucleation theory. Further, we address the shortcomings of the thermodynamic theory in describing the nucleation and emphasize the importance of nanoscale effects. This leads to the description of condensation from a molecular viewpoint. Also presented is how the nucleation can be simulated by use of molecular models, and how the condensation process is simulated on the macroscale using computational fluid dynamics. Finally, examples of hybrid models combining molecular and macroscale models for the simulation of condensation on a surface are presented.

  5. Are Earthquakes a Critical Phenomenon?

    NASA Astrophysics Data System (ADS)

    Ramos, O.

    2014-12-01

    Earthquakes, granular avalanches, superconducting vortices, solar flares, and even stock markets are known to evolve through power-law distributed events. During decades, the formalism of equilibrium phase transition has coined these phenomena as critical, which implies that they are also unpredictable. This work revises these ideas and uses earthquakes as the paradigm to demonstrate that slowly driven systems evolving through uncorrelated and power-law distributed avalanches (UPLA) are not necessarily critical systems, and therefore not necessarily unpredictable. By linking the correlation length to the pdf of the distribution, and comparing it with the one obtained at a critical point, a condition of criticality is introduced. Simulations in the classical Olami-Feder-Christensen (OFC) earthquake model confirm the findings, showing that earthquakes are not a critical phenomenon. However, one single catastrophic earthquake may show critical properties and, paradoxically, the emergence of this temporal critical behaviour may eventually carry precursory signs of catastrophic events.

  6. Translation as a psycholinguistic phenomenon.

    PubMed

    Zasyekin, Serhiy

    2010-06-01

    The article sketches the outlines of a theoretical framework for the analysis of translation of literary texts, viewed as psycho-semiotic phenomenon and based on evaluation of earlier attempts in this direction, and on the results of a psycholinguistic empirical study of translations. Central to this framework is the recent insight that the human cerebral hemisphere functional asymmetry somehow plays a role in structuring the fictional text by its author and in its processing by the interpreter. It is argued that the texts of modernism and post-modernism contain information blocks describing a character's perception of events in altered states of consciousness. This model helps to explain how a translator's inappropriate linguistic choice may influence the target language reader's aesthetic reaction.

  7. Nature

    NASA Astrophysics Data System (ADS)

    Heinhorst, Sabine; Cannon, Gordon

    1997-01-01

    The fact that two of the original articles by this year's Nobel laureates were published in Nature bears witness to the pivotal role of this journal in documenting pioneering discoveries in all areas of science. The prize for Physiology or Medicine was awarded to immunologists Peter C. Doherty (University of Tennessee) and Rolf M. Zinkernagel (University of Zurich, Switzerland), honoring work that, in the 1970s, laid the foundation for our current understanding of the way in which our immune system differentiates between healthy cells and virus-infected ones that are targeted for destruction (p 465 in the October 10 issue of vol. 383). Three researchers share the Chemistry award for their discovery of C60 buckminsterfullerenes. The work by Robert Curl, Richard Smalley (both at Rice University), and Harry Kroto (University of Sussex, UK) has led to a burst of new approaches to materials development and in carbon chemistry (p 561 of the October 17 issue of vol. 383). This year's Nobel prize in physics went to three U.S. researchers, Douglas Osheroff (Stanford University) and David M. Lee and Robert C. Richardson (Cornell University), who were honored for their work on superfluidity, a frictionless liquid state, of supercooled 3He (p 562 of the October 17 issue of vol. 383).

  8. Cell phenomenology: The first phenomenon.

    PubMed

    Pattee, H H

    2015-12-01

    As a broad academic discipline phenomenology may be summarized as the study from a first person point of view of what appears to subjective human conscious experience. As a historical philosophical movement phenomenology was often motivated by the belief that subjective human experience is the proper foundation of all philosophy. I explore phenomena from a broader evolutionary and physical point of view. I consider a phenomenon as the subjective consequence of a physical interaction with an individual organism. In physical terms, a phenomenon requires some form of detection or measurement. What is detected is determined by the organism, and is potentially functional for the organism as a self or subject. The concept of function has meaning only for living organisms. The classical human mind-body problem is an ill-defined complicated case of the more general epistemic subject-object problem, which at the origin of life I reduce to the primitive symbol-matter problem. I argue that the first memory-based self-replicating unit, like a cell, is the most primitive case of a necessary symbol-matter distinction. The first phenomena, which include all forms or sensing, detection, and measurement, require a subject-object distinction, called the epistemic cut. It is only because of such a subject-object distinction that populations of individual subjects can selectively adapt to their environment by heritable variations. This basic evolutionary process requires distinguishing the individual's subjective phenomena from the objective events of inexorable physical laws. Copyright © 2015. Published by Elsevier Ltd.

  9. The United States pork niche market phenomenon.

    PubMed

    Honeyman, M S; Pirog, R S; Huber, G H; Lammers, P J; Hermann, J R

    2006-08-01

    After the broad industrialization of the US pork industry, there has been a development of niche markets for export and domestic pork; that is, there is a pork niche market phenomenon. The US pork niche market phenomenon is characterized, and 2 of the major markets are explained in detail. With the Midwest's tradition of a diversified family-based agriculture and record low hog prices of the late 1990s, the conditions were conducive for this phenomenon to develop. Pork niche markets utilize various sales methods including Internet sales, local abattoir sales, direct marketing, farmer networks, and targeting to organized groups. In 2003, there were approximately 35 to 40 active pork niche marketing efforts in Iowa. The Berkshire breed is an example of a swine breed that has had a recent resurgence because of niche markets. Berkshire pork is known for tenderness and excellent quality. Berkshire registrations have increased 4-fold in the last 10 yr. One of the larger niche marketers of "natural pork" is Niman Ranch Pork, which has more than 400 farmer-producers and processes about 2,500 pigs weekly. Many US consumers of pork are interested in issues concerning the environment, food safety, pig welfare, and pig farm ownership and structure. These consumers may be willing to pay more for pork from farmers who are also concerned about these issues. Small- and medium-sized swine farmers are active in pork niche markets. Niche markets claim product differentiation by superior or unique product quality and social attributes. Quality attributes include certain swine breeds, and meat quality, freshness, taste or flavor, and tenderness. Social or credence attributes often are claimed and include freedom from antibiotics and growth promotants; local family farm production; natural, organic, outdoor, or bedded rearing; humane rearing; known origin; environmentally friendly production; and the absence of animal by-products in the feed. Niche pork markets and alternative swine

  10. The role of ocean phenomenon in music compositions

    NASA Astrophysics Data System (ADS)

    Liu, Chi-Min

    2016-04-01

    This is a preliminarily interdisciplinary study for exploring the elements of ocean phenomenon appearing in some compositions of classical music. The so-called ocean phenomenon contain wave conditions, climate change, coastal landform, and other natural events around or over the sea. In some music compositions, it is apparent that natural phenomenon over the sea influence the composers' moods and the music pieces they composed. In this poster, some music compositions in the 19th and the early 20th centuries will be introduced to demonstrate the relation between ocean and music works. These works include Meeresstille by Schubert, Étude Op.25 No.12 by Chopin, Fingal's Cave Overture by Mendelssohn, Der Fliegende Holländer by Wagner and La Mer by Debussy. In addition, present idea may give a novel way for music teachers to elucidate the knowledge of ocean science in classes.

  11. Circulating CD56dim natural killer cells and CD56+ T cells that produce interferon-γ or interleukin-10 are expanded in asymptomatic, E antigen-negative patients with persistent hepatitis B virus infection.

    PubMed

    Conroy, M J; Mac Nicholas, R; Grealy, R; Taylor, M; Otegbayo, J A; O'Dea, S; Mulcahy, F; Ryan, T; Norris, S; Doherty, D G

    2015-03-01

    Infection with hepatitis B virus (HBV) can result in spontaneous resolution or chronic infection, which can remain asymptomatic or can progress to cirrhosis and/or hepatocellular carcinoma. The host immune response is thought to be a major determinant of the outcome of HBV infection and virus-specific cytotoxic T lymphocytes (CTL) can mediate immunity against the virus and cause liver pathology. Antigen-nonspecific innate lymphocytes may also contribute to HBV infection and liver disease, therefore, we examined the frequencies, phenotypes, cytolytic activities and cytokine profiles of circulating natural killer (NK) cells, CD1d-restricted invariant natural killer T (iNKT) cells and CD56(+) T cells in 102 asymptomatic HBV-infected patients and compared them with those in 66 uninfected control subjects. NK cells expressing low levels of CD56 (CD56(dim)) and CD56(+) T cells were significantly expanded in the circulation of HBV-infected patients compared with control subjects. CD1d expression and iNKT cell frequencies were similar in both groups. Despite these expansions, we did not detect augmented natural or cytokine-induced cytotoxicity in the HBV-infected subjects. All lymphocyte populations studied produced interferon-γ (IFN-γ) significantly more frequently when taken from HBV-infected patients compared with when taken from healthy controls. Additionally, NK cells from the patients more frequently produced interleukin-10. As our HBV-infected cohort consisted of asymptomatic patients with low viral loads, we propose that CD56(dim) NK cells and CD56(+) T cells control HBV infection by noncytolytic mechanisms.

  12. Natural Circulation in the Blanket Heat Removal System During a Loss-of-Pumping Accident (LOFA) Based on Initial Conceptual Design

    SciTech Connect

    Hamm, L.L.

    1998-10-07

    A transient natural convection model of the APT blanket primary heat removal (HR) system was developed to demonstrate that the blanket could be cooled for a sufficient period of time for long term cooling to be established following a loss-of-flow accident (LOFA). The particular case of interest in this report is a complete loss-of-pumping accident. For the accident scenario in which pumps are lost in both the target and blanket HR systems, natural convection provides effective cooling of the blanket for approximately 68 hours, and, if only the blanket HR systems are involved, natural convection is effective for approximately 210 hours. The heat sink for both of these accident scenarios is the assumed stagnant fluid and metal on the secondary sides of the heat exchangers.

  13. Leidenfrost phenomenon on conical surfaces

    NASA Astrophysics Data System (ADS)

    Hidalgo-Caballero, S.; Escobar-Ortega, Y.; Pacheco-Vázquez, F.

    2016-09-01

    The Leidenfrost state is typically studied by placing droplets on flat or slightly curved surfaces. Here this phenomenon is investigated by depositing water in hot conical bowls. We found that this phase exists even for large amounts of liquid in very narrow cones without considerable effect of the confinement on the Leidenfrost transition temperature TL. At a fixed temperature, T >TL , the total evaporation time τ has a nonmonotonic dependence on the angle of confinement θ : for large volumes (˜20 ml) on flat surfaces (θ ˜0∘ ), vapor chimneys appear and accelerate the evaporation rate, their frequency diminishes as θ augments and becomes zero at a certain angle θc, at which τ reaches its maximum value; then, τ decreases again at larger angles because the vapor layer holding up the water becomes thinner due to the increase of hydrostatic pressure and because the geometry facilitates the vapor expulsion along the conical wall. For small volumes (˜1 ml), surface tension mainly determines the drop curvature and the lifetime is practically independent of θ . Different chimney regimes and oscillation patterns were observed and summarized in a phase diagram. Finally, we developed a simple model to decipher the shape adopted by the liquid volume and its evolution as a function of time, and the predictions are in good agreement with the experimental results.

  14. The phenomenon of Soviet science.

    PubMed

    Kojevnikov, Alexei

    2008-01-01

    The grand "Soviet experiment" constituted an attempt to greatly accelerate and even shortcut the gradual course of historical development on the assumption of presumed knowledge of the general laws of history. This paper discusses the parts of that experiment that directly concerned scientific research and, in fact, anticipated or helped define important global changes in the functioning of science as a profession and an institution during the twentieth century. The phenomenon of Soviet, or socialist, science is analyzed here from the comparative international perspective, with attention to similarities and reciprocal influences, rather than to the contrasts and dichotomies that have traditionally interested cold war-type historiography. The problem is considered at several levels: philosophical (Soviet thought on the relationship between science and society and the social construction of scientific knowledge); institutional (the state recognition of research as a separate profession, the rise of big science and scientific research institutes); demographic (science becoming a mass profession, with ethnic and gender diversity among scientists); and political (Soviet-inspired influences on the practice of science in Europe and the United States through the social relations of science movement of the 1930s and the Sputnik shock of the 1950s).

  15. Dispensing with the DVD Circulation Dilemma

    ERIC Educational Resources Information Center

    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…

  16. Dispensing with the DVD Circulation Dilemma

    ERIC Educational Resources Information Center

    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…

  17. Surface phenomenon in Electrochemical Systems

    NASA Astrophysics Data System (ADS)

    Gupta, Tanya

    Interfaces play a critical role in the performance of electrochemical systems. This thesis focusses on interfaces in batteries and covers aspects of interfacial morphologies of metal anodes, including Silicon, Lithium and Zinc. Growth and cycling of electrochemically grown Lithium and Zinc metal structures is investigated. A new morphology of Zinc, called Hyper Dendritic Zinc is introduced. It is cycled against Prussian Blue Analogues and is shown to improve the performance of this couple significantly. Characterization of materials is done using various electron microscopy techniques ranging from Low Energy Electron Microscope (LEEM), to high energy Transmission Electron Microscope (TEM). LEEM is used for capturing subtle surface phenomenon occurring during epitaxial process of electrolyte on anode. The system studied is Silicon (100) during Chemical Vapor Deposition of Ethylene Carbonate. A strain driven relaxation theory is modeled to explain the unusual restructuring of Si substrate. The other extreme, TEM, is often used to study electrochemical processes, without clear understanding of how the high-energy electron beam can influence the sample under investigation. Here, we study the radiolysis in liquid cell TEM and emphasize on the enhancement of radiation dose at interfaces of the liquid due to generation of secondary and backscattered electrons from adjoining materials. It is shown that this effect is localized in a 10 nm region around the interface and can play a dominating role if there is an interface of liquid with heavy metals like Gold and Platinum which are frequently used as electrode materials. This analysis can be used to establish guidelines for experimentalists to follow, for accurate interpretation of their results.

  18. Global QBO in circulation and ozone. Part 2: A simple mechanistic model

    SciTech Connect

    Tung, K.K.; Yang, H.

    1994-10-01

    Although the phenomenon of equatorial quasi-biennial oscillation is relatively well understood, the problem of how the equatorially confined quasi-biennial oscillation (QBO) wave forcing can induce a signal in the extratropics of comparable or larger magnitude remains unsolved. A simple mechanistic model is constructed to provide a quantitative test of the hypothesis that the phenomenon of extratropical QBO is mainly caused by an anomalous seasonal circulation induced by an anomalous Eliassen-Palm (E-P) flux divergence. The anomaly in E-P flux divergence may be caused in turn by the relative poleward and downward shift of the region of irreversible mixing (breaking) of the extratropical planetary waves during the easterly phase of the equatorial QBO as compared to its westerly phase. The hemispheric nature of the anomaly wave forcing in solstice seasons (viz., no wave breaking in the summer hemisphere) induces a global circulation anomaly that projects predominantly into the first few zonal Hough modes of Plumb. Such a global QBO circulation pattern, although difficult to measure directly, is reflected in the distribution of stratospheric tracers transported by it. Our model produces a global pattern of QBO anomaly in column ozone that appears to account for much of the unfiltered interannual variability in the column ozone observed by the total ozone mapping spectrometer (TOMS) instrument aboard the Nimbus satellite. Furthermore, the model produces the characteristic spectrum of the observation with peaks at periods of 20 and 30 months.

  19. Global QBO in circulation and ozone. Part 2: A simple mechanistic model

    NASA Technical Reports Server (NTRS)

    Tung, K. K.; Yang, H.

    1994-01-01

    Although the phenomenon of equatorial quasi-biennial oscillation is relatively well understood, the problem of how the equatorially confined quasi-biennial oscillation (QBO) wave forcing can induce a signal in the extratropics of comparable or larger magnitude remains unsolved. A simple mechanistic model is constructed to provide a quantitative test of the hypothesis that the phenomenon of extratropical QBO is mainly caused by an anomalous seasonal circulation induced by an anomalous Eliassen-Palm (E-P) flux divergence. The anomaly in E-P flux divergence may be caused in turn by the relative poleward and downward shift of the region of irreversible mixing (breaking) of the extratropical planetary waves during the easterly phase of the equatorial QBO as compared to its westerly phase. The hemispheric nature of the anomaly wave forcing in solstice seasons (viz., no wave breaking in the summer hemisphere) induces a global circulation anomaly that projects predominantly into the first few zonal Hough modes of Plumb. Such a global QBO circulation pattern, although difficult to measure directly, is reflected in the distribution of stratospheric tracers transported by it. Our model produces a global pattern of QBO anomaly in column ozone that appears to account for much of the unfiltered interannual variability in the column ozone observed by the total ozone mapping spectrometer (TOMS) instrument aboard the Nimbus satellite. Furthermore, the model produces the characteristic spectrum of the observation with peaks at periods of 20 and 30 months.

  20. Dynamic Group Formation Based on a Natural Phenomenon

    ERIC Educational Resources Information Center

    Zedadra, Amina; Lafifi, Yacine; Zedadra, Ouarda

    2016-01-01

    This paper presents a new approach of learners grouping in collaborative learning systems. This grouping process is based on traces left by learners. The goal is the circular dynamic grouping to achieve collaborative projects. The proposed approach consists of two main algorithms: (1) the circular grouping algorithm and (2) the dynamic grouping…

  1. The Essential Nature and Types of the Youth Subculture Phenomenon

    ERIC Educational Resources Information Center

    Latysheva, T. V.

    2011-01-01

    Youth subcultures in Russia have become more like those found in other societies. The article presents typologies of youth subculture types and trends. Attitudes toward them vary by urban/rural, economic, educational, and geographic characteristics. (Contains 2 tables and 2 figures.)

  2. An interesting natural phenomenon - giant rings on Lake Baikal ice

    NASA Astrophysics Data System (ADS)

    Kouraev, Alexei; Shimaraev, Michail; Remy, Frederique; Ivanov, Andrei; Golubov, Boris

    2010-05-01

    Starting from May 2009 scientific community and large public have been puzzled by the formation of giant rings on Baikal ice. These rings (diameter 5-7 km, thickness of dark layer - 1 - 1.8 km) have almost perfect circular shape what makes them so interesting and attractive not only to scientists, but also for large public. . The rings have been observed since 1999 by various satellites and sensors (AVHRR, MODIS, Landsat, SPOT) as early as 1999 but probably also in 1984 and 1994 (Shuttle missions). These rings are usually well observed in April, when snow cover is thin or absent. Rings have been observed in the southern tip of the lake (2009), and in three places in the central part: near Krestovskiy cape (1999, 2003, 2005 and 2008), near Turka (2008), and near Cape Nizhnee Izgolovye (2009). All these places are located in the region of steep bottom topography, over depths of more than 500 m. According to in situ measurements done by the Limnological Institute in Irkutsk in 2009, ice thickness is about 70 cm in the center and on the outside of the ring, and 40 cm in the ring itself. It is known that the Baikal lake has important hydrothermal activity, and there are numerous observations of gas (methane etc) seepage from its 7 km-thick layer of bottom sediments. Local-scale absence of ice cover (steamthroughs or "propariny") is typical for some places in Lake Baikal. They result from gas emissions (associated with rise of warm water), near capes and straits (due to better vertical mixing), thermal sources, outlets of large rivers. Often they are observed near Capes Big and Small Kadil'niy, and in the Olkhonskiye vorota strait. However they size ranges from just a half a meter to several hundreds of meters (but not several kilometers) and this could not be an explanation for the formation of giant rings. We present several existing hypotheses of the origin of these rings including gas emission, heat flux, cyclonic subsurface currents and mega-bubble formation due to gas seepage and discuss strengths and weaknesses of each hypothesis. We also discuss the possibility of methane release from gas hydrates deposits that occur at depths more than 350-500 m in the Southern and Central Baikal. Hydrates can be destabilised by tectonic/seismic activity or by increased heat flow due to hydrothermal activity and lead to catastrophic gas blow-out events. We analyse the timing of observation of ice rings and regional seismicity from the USGS seismic data (earthquake activity and hypocenter depth) showing recent changes between 1992 and 1999. We present observation of the formation, development and disappearance of these rings using optical and infra-red imagery (MODIS, Landsat), complemented by SAR imagery (ERS-2 SAR, ENVISAT ASAR). We also analyse radar altimetry observations (ENVISAT RA2) in the region of Cape Krestovskiy in the Middle Baikal. We discuss the conditions needed to create and maintain these rings, the timing of and duration of their existence, as well as horizontal and vertical structure of ice and snow cover before and during the appearance of rings. This research has been done in the framework of the Russian-French cooperation GDRI "CAR-WET-SIB", French ANR "IMPACT-Boreal" project and FP7 MONARCH-A project.

  3. The Essential Nature and Types of the Youth Subculture Phenomenon

    ERIC Educational Resources Information Center

    Latysheva, T. V.

    2011-01-01

    Youth subcultures in Russia have become more like those found in other societies. The article presents typologies of youth subculture types and trends. Attitudes toward them vary by urban/rural, economic, educational, and geographic characteristics. (Contains 2 tables and 2 figures.)

  4. Dynamic Group Formation Based on a Natural Phenomenon

    ERIC Educational Resources Information Center

    Zedadra, Amina; Lafifi, Yacine; Zedadra, Ouarda

    2016-01-01

    This paper presents a new approach of learners grouping in collaborative learning systems. This grouping process is based on traces left by learners. The goal is the circular dynamic grouping to achieve collaborative projects. The proposed approach consists of two main algorithms: (1) the circular grouping algorithm and (2) the dynamic grouping…

  5. Circulation in blast driven instabilities

    NASA Astrophysics Data System (ADS)

    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.

  6. Measurement of cold challenge responses in primary Raynaud's phenomenon and Raynaud's phenomenon associated with systemic sclerosis.

    PubMed Central

    O'Reilly, D; Taylor, L; el-Hadidy, K; Jayson, M I

    1992-01-01

    Using computed thermography continuous temperature recordings were made before and after cold challenge of the fingers of control subjects and patients with primary Raynaud's phenomenon and Raynaud's phenomenon associated with systemic sclerosis. Basal skin temperature measurements (Tpre) were significantly lower in patients with primary Raynaud's phenomenon and Raynaud's phenomenon associated with systemic sclerosis than in the controls. Temperatures immediately after cold challenge (T0) were significantly lower in patients with primary Raynaud's phenomenon and Raynaud's phenomenon associated with systemic sclerosis than in controls. The lag phase before the start of temperature recovery (Tlag) was significantly greater in patients with primary Raynaud's phenomenon and Raynaud's phenomenon associated with systemic sclerosis than in control subjects. The maximum recovery index (R%) was significantly less in patients with primary Raynaud's phenomenon and Raynaud's phenomenon associated with systemic sclerosis than in controls. The maximum rate of change of temperature during the rapid phase of rewarming (Gmax) was significantly greater in controls than in patients with primary Raynaud's phenomenon and Raynaud's phenomenon associated with systemic sclerosis. Discriminant analysis showed that the dynamic parameters of rewarming (Tlag, Gmax, and R%) showed greater variation between the patients with primary Raynaud's phenomenon and those with Raynaud's phenomenon associated with systemic sclerosis than did Tpre or T0. This method of analysis of cold challenge will be used in studies of the effects of treatment of Raynaud's phenomenon. PMID:1466594

  7. Monostotic fibrous dysplasia with Raynaud's phenomenon

    PubMed Central

    Kumar, K. V. S. Hari; Aravinda, K.; Narayanan, K.

    2015-01-01

    Fibrous dysplasia (FD) is a benign bone disorder characterized by alteration in bone morphology. Monostotic FD is the commonest variant and affects the craniofacial bones. Raynaud's phenomenon is recurrent vasospasm of the fingers and toes due to cold exposure. The disease is usually idiopathic or secondary to connective tissue disorders. Raynaud's phenomenon is not described previously with FD. We recently encountered two interesting patients of craniofacial monostotic FD with Raynaud's phenomenon and report the same in this report. PMID:26283854

  8. Monostotic fibrous dysplasia with Raynaud's phenomenon.

    PubMed

    Kumar, K V S Hari; Aravinda, K; Narayanan, K

    2015-01-01

    Fibrous dysplasia (FD) is a benign bone disorder characterized by alteration in bone morphology. Monostotic FD is the commonest variant and affects the craniofacial bones. Raynaud's phenomenon is recurrent vasospasm of the fingers and toes due to cold exposure. The disease is usually idiopathic or secondary to connective tissue disorders. Raynaud's phenomenon is not described previously with FD. We recently encountered two interesting patients of craniofacial monostotic FD with Raynaud's phenomenon and report the same in this report.

  9. The Isakower phenomenon revisited: a case study.

    PubMed

    Dann, O T

    1992-01-01

    The Isakower phenomenon is a situation in which an individual typically experiences perceptions of enlargement or thickening, altered states of consciousness, sensations of floating, and impressions of the emergence and disappearance of an oral mass. This paper defines the phenomenon, reviews the literature, and describes a case in which a patient experienced it. The patient manifested the phenomenon symptomatically in the aftermath of a toxic state, and the elements were analysed for several years. There was support for Isakower's original thesis that the regressive states serve to defend against threatening incestuous fantasies. However, the Isakower phenomenon in this patient was the result of a multiplicity of determinants, largely defensive, involving many developmental levels.

  10. The Born-again phenomenon

    NASA Astrophysics Data System (ADS)

    Evans, Aneurin

    2015-10-01

    We will continue and extend our highly successful Cycle 2/3 observations, and use SOFIA FORCAST grism and imaging observations to obtain the spectral energy distributions of stars that have recently undergone very late thermal pulses. These very rare, poorly observed, and little understood events can potentially give us a glimpse of the eventual fate of the Sun and other low-mass stars. With continued FORCAST spectral and photometric coverage from 4.9 - 37.1 microns we will be able to determine the mass-loss rate from the central star and its variability, its physical state, and the nature and extent of its circumstellar dust shell. Our observations will throw light on a phase of the evolution of low mass stars that is very poorly understood.

  11. The Born-again Phenomenon

    NASA Astrophysics Data System (ADS)

    Evans, Aneurin

    2013-10-01

    We will use SOFIA FORCAST and FLITECAM grism observations to obtain the spectral energy distributions of stars that have recently undergone very late thermal pulses. These are very rare, poorly observed, and little understood events that can potentially give us a glimpse of the eventual fate of the Sun. With spectral coverage from 2.6 - 37.1 microns we will be able to determine the mass-loss rate from the central star, its physical state and the nature and extent of its circumstellar dust shell. We will also be able to characterize carriers of the Unidentified Infrared (UIR) emission from those objects displaying such emission. Our observations will throw light on a phase of the evolution of low mass stars that is very poorly understood.

  12. A single acute dose of pinitol from a naturally-occurring food ingredient decreases hyperglycaemia and circulating insulin levels in healthy subjects.

    PubMed

    Hernández-Mijares, Antonio; Bañuls, Celia; Peris, Jose E; Monzó, Nuria; Jover, Ana; Bellod, Lorena; Victor, Victor M; Rocha, Milagros

    2013-11-15

    A limited amount of research suggests that oral ingestion of pinitol (3-O-methyl-d-chiro-inositol) positively influences glucose tolerance in humans. This study assessed the effects of different doses of pinitol supplementation on glucose tolerance, insulin sensitivity and plasma pinitol concentrations. Thirty healthy subjects underwent two one-day trials in which they consumed a nutritive beverage (Fruit Up®) containing 2.5, 4.0 or 6.0g of pinitol and a corresponding placebo equivalent in both energy and carbohydrates. Blood samples were collected frequently over the 240-min test period. The pinitol-enriched beverage reduced serum glucose and insulin at 45 and 60min, but only at a dose of 6.0g. Plasma pinitol concentrations, maximum concentration and AUC increased according to the dose administered. The results show that a single dose of pinitol from a naturally-occurring food ingredient at the highest dose administered acutely influences indices of whole-body glucose tolerance and insulin sensitivity in healthy subjects. Copyright © 2013 Elsevier Ltd. All rights reserved.

  13. MELCOR 1.8.5 Simulation of TMI-2 Phase 2 With an Enhanced 2-Dimensional In-Vessel Natural Circulation Model

    SciTech Connect

    Gauntt, Randall O.; Ross, Kyle; Wagner, Kenneth

    2002-07-01

    Phase 2 of the TMI-2 accident (core uncover and melting) is revisited with the latest release of MELCOR (i.e., Version 1.8.5). An enhanced multi-ring multi-level hydro nodalization of the reactor core and upper plenum was developed to permit calculation of natural convection heat transfer between the core and upper internals. Uncertainties in boundary and initial conditions are investigated with particular attention given to the distribution of liquid in the RCS at the beginning of Phase 2 and to the histories of pressure and level in the steam generators. Special attention given to modeling the boiler sides of the once-through steam generators is presented. The modeling is designed to capture the rapid condensation of RCS vapor that would result from spraying cold auxiliary feedwater directly onto the upper portion of a voided steam generator tube bundle. Presentation of key Phase-2 accident signatures including fuel temperatures and hydrogen generation are presented. Comparisons are made between MELCOR calculations, TMI-2 data, and SCDAP/RELAP simulations. A largely improved MELCOR simulation of TMI-2 Phase 2 is obtained. (authors)

  14. Hydrothermal circulation along oceanic detachment fault: Constraints on the nature and conditions of syntectonic silicification at the 13°20'N oceanic core complex (Mid-Atlantic ridge)

    NASA Astrophysics Data System (ADS)

    Bonnemains, D.; Verlaguet, A.; Escartin, J.; Mevel, C.; Andreani, M.

    2016-12-01

    To understand the link between extreme strain localization and fluid flow at long-lived oceanic detachment faults, we present results of geological investigations at the active 13°20'N detachment fault along the Mid-Atlantic ridge (ODEMAR cruise, Nov-Dec13) onboard NO Pourquoi pas? using the ROV Victor6000. During this cruise, we identified and sampled 7 fault outcrops on the flanks of detachment microbathymetric corrugations. These fault surfaces, extending up to 100m laterally, with extension-parallel subhorizontal striations. Sampled fault rocks are breccias containing mainly diabase clasts (often altered) and rare ultramafic clasts. Samples also show striated surfaces indicating strain localization at outcrop to sample scales. These fault rocks, which show pervasive syntectonic silicification during fault exhumation, are not documented along other detachments. To constrain the nature and origin of the silicifying fluids and the conditions of fluid-rock interactions, we combined whole-rock and mineral analyses with a study of fluid inclusions in quartz. Highly silicified samples record high homogenization temperatures (250-350°C), while moderate silicification temperatures are lower (150-250°C). In all cases salinities are generally higher than seawater (4-10 wt% eq. NaCl). These high salinity fluids likely record phase separation at high temperature (>400°C), and Raman spectroscopy shows that they contain H2±CH4±CO2. These results suggest an interaction of these fluids with ultramafic rocks undergoing serpentinization reactions (H2 release) in the footwall of the detachment and the presence of a high temperature zone at depth. This is supported by trace element patterns of mafic breccias, which shift towards ultramafic compositions with increasing silicification degree. The detachment fault zone thus channels and records a tectonic mixing between hydrothermal serpentinite fluids, and shallower seawater-like fluids potentially from the mafic hanging wall.

  15. Terrorism as a Social and Legal Phenomenon

    ERIC Educational Resources Information Center

    Serebrennikova, Anna; Mashkova, Yekaterina

    2017-01-01

    This article examines the concept of terrorism as a social and legal phenomenon, its international legal and criminal-legal characteristics. Highlighted are the main aspects of cooperation of the states and the international community to counter terrorist activities. Terrorism as a social phenomenon is determined by paragraph 1 of article 3 of the…

  16. A Gadamerian Investigation of the Two Cultures Phenomenon in an Undergraduate Honors Research Fellowship

    ERIC Educational Resources Information Center

    Giazzoni, Michael J.

    2009-01-01

    The Two Cultures phenomenon, first given its name by C. P. Snow in 1956, consists of a conflict between participants in the academic communities of the natural sciences and the humanities; it also mirrors the methodological debate in the social sciences. This phenomenon also occurs in undergraduates in an interdisciplinary research fellowship at…

  17. A Gadamerian Investigation of the Two Cultures Phenomenon in an Undergraduate Honors Research Fellowship

    ERIC Educational Resources Information Center

    Giazzoni, Michael J.

    2009-01-01

    The Two Cultures phenomenon, first given its name by C. P. Snow in 1956, consists of a conflict between participants in the academic communities of the natural sciences and the humanities; it also mirrors the methodological debate in the social sciences. This phenomenon also occurs in undergraduates in an interdisciplinary research fellowship at…

  18. Circulating glioma biomarkers

    PubMed Central

    Kros, Johan M.; Mustafa, Dana M.; Dekker, Lennard J.M.; Sillevis Smitt, Peter A.E.; Luider, Theo M.; Zheng, Ping-Pin

    2015-01-01

    Validated biomarkers for patients suffering from gliomas are urgently needed for standardizing measurements of the effects of treatment in daily clinical practice and trials. Circulating body fluids offer easily accessible sources for such markers. This review highlights various categories of tumor-associated circulating biomarkers identified in blood and cerebrospinal fluid of glioma patients, including circulating tumor cells, exosomes, nucleic acids, proteins, and oncometabolites. The validation and potential clinical utility of these biomarkers is briefly discussed. Although many candidate circulating protein biomarkers were reported, none of these have reached the required validation to be introduced for clinical practice. Recent developments in tracing circulating tumor cells and their derivatives as exosomes and circulating nuclear acids may become more successful in providing useful biomarkers. It is to be expected that current technical developments will contribute to the finding and validation of circulating biomarkers. PMID:25253418

  19. The Fleischmann-Pons phenomenon; Different perspective

    SciTech Connect

    Ray, M.K.S.; Saini, R.D.; Das, D.; Chattopadhyay, G.; Parthasarathy, R.; Garg, S.P.; Venkataramani, R.; Sen, B.K.; Iyengar, T.S.; Kutty, K.K. )

    1992-11-01

    This paper reports on attempts which have been made to initiate the Fleischmann-Pons phenomenon through selective perturbations during experimental studies in divided electrolytic cells. Despite wide variations in the operating parameters and the attainment of high loading (sometimes up to D/Pd [approx] 2), the phenomenon was not observed either during the unperturbed electrolysis or on physical perturbation. However, instances of its occurrence were observed when the state of equilibrium of the deuterated cathode (having a scale free portion) was chemically perturbed by oxygen. This observation, viewed in light of available information, is indicative of oxygen playing a vital role in the phenomenon.

  20. [Gregg phenomenon and garden hose effect].

    PubMed

    Schipke, J D; Frehen, D

    2001-05-01

    Under physiologic circumstances, cardiac function determines myocardial oxygen consumption and consequently coronary perfusion. Surprisingly, in a reverse direction, improved coronary perfusion also increased myocardial oxygen consumption and contractile function. This experimental finding, now 40 years old, is termed the Gregg phenomenon. Some 10 years later, in experiments by Arnold and co-workers, an isolated increase in perfusion pressure improved ventricular function. In this context, the term 'gardenhose effect' was coined, implying a hydraulic explanation of the Gregg phenomenon. In the following, we attempt to distinguish the Gregg phenomenon from the gardenhose effect and to critically evaluate them.

  1. The B[e] Phenomenon in Symbiotic Binaries

    NASA Astrophysics Data System (ADS)

    Skopal, A.

    2017-02-01

    The spectrum of symbiotic stars (SSs) consists of three basic components of radiation. Two are stellar in nature are produced by the binary components, the evolved cool giant and the hot compact component, whereas the third one is the nebular in nature being rich for emission lines. An additional component from a dust is observed in the near-IR spectrum of the so-called D-type (dusty) SSs. In this contribution I introduce the basic physical processes responsible for the symbiotic phenomenon, model the composite spectrum, and point to a striking similarity of the configuration of B[e] supergiants with that of the hot components during outbursts of SSs.

  2. A classical case of the Gasul phenomenon.

    PubMed

    Sabnis, Girish R; Phadke, Milind S; Kerkar, Prafulla G

    2016-02-01

    This case demonstrates the development of secondary infundibular stenosis in a 10-year-old male child with documented large non-restrictive perimembranous ventricular septal defect in infancy - the classical Gasul phenomenon.

  3. The lean hunting phenomenon in gasoline engines

    SciTech Connect

    Tanaka, M.; Mochizuki, S.; Nishiwaki, N.; Miyake, M.

    1987-01-01

    A quite interesting self-excited oscillation phenomenon in engine speed, which may not be explained with the classical theory of mechanical hunting, is studied experimentally. The effects of the various engine operating variables on the phenomenon are examined using a four cycle single cylinder gasoline engine with an inertia governor. It was found that the phenomenon occurs when engines are operated at a lean air fuel ratio under light load conditions, and that the hunting phenomenon is ascribable to the temporary shift in air fuel ratio from the steady state value. This shift in air fuel ratio occurs due to the fuel flow delay into the cylinder caused by the fact that the fuel flow into the cylinder cannot follow the movement of the throttle valve.

  4. Orgasm Induced Seizures: A Rare Phenomenon.

    PubMed

    Chaukimath, S P; Patil, P S

    2015-01-01

    A variety of stimuli can cause reflex seizures, Some triggers include light, music and cognitive phenomenon. There are case reports however where the phenomenon of sexual activity has been a trigger for epileptic seizures. Most of these cases reported are in women so far, and were found to be localized to right cerebral hemisphere. We report a case of a 36-year-old male with orgasm-induced seizures, with other atypical features compared to majority of previous reports.

  5. PP composites with Hybrid Nanofillers: NTC phenomenon

    NASA Astrophysics Data System (ADS)

    Sarlin, Juha; Immonen, Kirsi

    2010-06-01

    Electric conductive plastic composites have a wide potential for commercial applications, some examples are EMI shielding housings and components in automotive industry and in consumer electronics, equipments in health care sector and fuel cell components. A phenomenon in conductive composites, especially in composites with carbon based fillers, is change of thermal induced change in conductivity as a result of morphological transitions. Usually the observed changes are practically irreversible. The phenomenon may cause increasing resistivity, usually called as "positive temperature coefficient" (PTC) or decreasing resistivity, called "negative temperature coefficient (NTC), where the new morphology created by heat treatment is more favorable for electric conductivity compared to the original state. The existence of NTC is a sing of the lost potential in material design and processing. Therefore detailed information about the phenomenon gives us tools to develop high performance conductive materials. It this paper we discuss about NTC phenomenon observed in PP composites with CNT or in-situ synthesized CNT-PANi hybrid nanofiller with an amphiphilic dispersing agent. The goal of the paper is not to present a comprehensive model of this phenomenon; we present some experimental results which may be related to polymer-filler interactions. These details are a part of this complicated phenomenon.

  6. Validation of the Impostor Phenomenon among Managers

    PubMed Central

    Rohrmann, Sonja; Bechtoldt, Myriam N.; Leonhardt, Mona

    2016-01-01

    Following up on earlier investigations, the present research aims at validating the construct impostor phenomenon by taking other personality correlates into account and to examine whether the impostor phenomenon is a construct in its own right. In addition, gender effects as well as associations with dispositional working styles and strain are examined. In an online study we surveyed a sample of N = 242 individuals occupying leadership positions in different sectors. Confirmatory factor analyses provide empirical evidence for the discriminant validity of the impostor phenomenon. In accord with earlier studies we show that the impostor phenomenon is accompanied by higher levels of anxiety, dysphoric moods, emotional instability, a generally negative self-evaluation, and perfectionism. The study does not reveal any gender differences concerning the impostor phenomenon. With respect to working styles, persons with an impostor self-concept tend to show perfectionist as well as procrastinating behaviors. Moreover, they report being more stressed and strained by their work. In sum, the findings show that the impostor phenomenon constitutes a dysfunctional personality style. Practical implications are discussed. PMID:27313554

  7. Apparatus Circulates Sterilizing Gas

    NASA Technical Reports Server (NTRS)

    Cross, John H.; Schwarz, Ray P.

    1991-01-01

    Apparatus circulates sterilizing gas containing ethylene oxide and chlorofluorocarbon through laboratory or medical equipment. Confines sterilizing gas, circulating it only through parts to be treated. Consists of two units. One delivers ethylene oxide/chlorofluorocarbon gas mixture and removes gas after treatment. Other warms, humidifies, and circulates gas through equipment to be treated. Process provides reliable sterilization with negligible residual toxicity from ethylene oxide. Particularly suitable for sterilization of interiors of bioreactors, heart/lung machines, dialyzers, or other equipment including complicated tubing.

  8. Coronary collateral circulation: its relevance.

    PubMed

    Karrowni, Wassef; El Accaoui, Ramzi N; Chatterjee, Kanu

    2013-11-15

    The interest in coronary collateral circulation (CCC) as "natural bypasses" is growing, especially in patients in whom the extent of coronary atherosclerosis is too severe to allow for conventional revascularization. The anatomic foundation of CCC has been recognized for long time. Recently, reliable methods have become available for the assessment of the adequacy of collateral flow. However, the debate regarding the importance of CCC in the different clinical settings continues. In this article, we present the recent progress in the understanding of anatomy and physiology of the CCC and focus on the studies addressing their functional significance in acute, subacute, and chronic coronary artery disease. In addition, we provide a focused update on the essential role of collateral circulation in the management of coronary chronic total occlusions.

  9. Persistent Changes in Circulating and Intestinal γδ T Cell Subsets, Invariant Natural Killer T Cells and Mucosal-Associated Invariant T Cells in Children and Adults with Coeliac Disease

    PubMed Central

    Dunne, Margaret R.; Elliott, Louise; Hussey, Seamus; Mahmud, Nasir; Kelly, Jacinta; Doherty, Derek G.; Feighery, Conleth F.

    2013-01-01

    Coeliac disease is a chronic small intestinal immune-mediated enteropathy precipitated by exposure to dietary gluten in genetically predisposed individuals. The only current therapy is a lifelong gluten free diet. While much work has focused on the gliadin-specific adaptive immune response in coeliac disease, little is understood about the involvement of the innate immune system. Here we used multi-colour flow cytometry to determine the number and frequency of γδ T cells (Vδ1, Vδ2 and Vδ3 subsets), natural killer cells, CD56+ T cells, invariant NKT cells, and mucosal associated invariant T cells, in blood and duodenum from adults and children with coeliac disease and healthy matched controls. All circulating innate lymphocyte populations were significantly decreased in adult, but not paediatric coeliac donors, when compared with healthy controls. Within the normal small intestine, we noted that Vδ3 cells were the most abundant γδ T cell type in the adult epithelium and lamina propria, and in the paediatric lamina propria. In contrast, patients with coeliac disease showed skewing toward a predominant Vδ1 profile, observed for both adult and paediatric coeliac disease cohorts, particularly within the gut epithelium. This was concurrent with decreases in all other gut lymphocyte subsets, suggesting a specific involvement of Vδ1 cells in coeliac disease pathogenesis. Further analysis showed that γδ T cells isolated from the coeliac gut display an activated, effector memory phenotype, and retain the ability to rapidly respond to in vitro stimulation. A profound loss of CD56 expression in all lymphocyte populations was noted in the coeliac gut. These findings demonstrate a sustained aberrant innate lymphocyte profile in coeliac disease patients of all ages, persisting even after elimination of gluten from the diet. This may lead to impaired immunity, and could potentially account for the increased incidence of autoimmune co-morbidity. PMID:24124528

  10. Persistent changes in circulating and intestinal γδ T cell subsets, invariant natural killer T cells and mucosal-associated invariant T cells in children and adults with coeliac disease.

    PubMed

    Dunne, Margaret R; Elliott, Louise; Hussey, Seamus; Mahmud, Nasir; Kelly, Jacinta; Doherty, Derek G; Feighery, Conleth F

    2013-01-01

    Coeliac disease is a chronic small intestinal immune-mediated enteropathy precipitated by exposure to dietary gluten in genetically predisposed individuals. The only current therapy is a lifelong gluten free diet. While much work has focused on the gliadin-specific adaptive immune response in coeliac disease, little is understood about the involvement of the innate immune system. Here we used multi-colour flow cytometry to determine the number and frequency of γδ T cells (Vδ1, Vδ2 and Vδ3 subsets), natural killer cells, CD56(+) T cells, invariant NKT cells, and mucosal associated invariant T cells, in blood and duodenum from adults and children with coeliac disease and healthy matched controls. All circulating innate lymphocyte populations were significantly decreased in adult, but not paediatric coeliac donors, when compared with healthy controls. Within the normal small intestine, we noted that Vδ3 cells were the most abundant γδ T cell type in the adult epithelium and lamina propria, and in the paediatric lamina propria. In contrast, patients with coeliac disease showed skewing toward a predominant Vδ1 profile, observed for both adult and paediatric coeliac disease cohorts, particularly within the gut epithelium. This was concurrent with decreases in all other gut lymphocyte subsets, suggesting a specific involvement of Vδ1 cells in coeliac disease pathogenesis. Further analysis showed that γδ T cells isolated from the coeliac gut display an activated, effector memory phenotype, and retain the ability to rapidly respond to in vitro stimulation. A profound loss of CD56 expression in all lymphocyte populations was noted in the coeliac gut. These findings demonstrate a sustained aberrant innate lymphocyte profile in coeliac disease patients of all ages, persisting even after elimination of gluten from the diet. This may lead to impaired immunity, and could potentially account for the increased incidence of autoimmune co-morbidity.

  11. Fontan Circulation over Time.

    PubMed

    Wolff, Djoeke; van Melle, Joost P; Bartelds, Beatrijs; Ridderbos, Floris-Jan S; Eshuis, Graziella; van Stratum, Elisabeth B H J; Recinos, Salvador J; Willemse, Brigitte W M; Hillege, Hans; Willems, Tineke P; Ebels, Tjark; Berger, Rolf M F

    2017-08-01

    The unique, unphysiological Fontan circulation is associated with an impaired functional status of the patients that is suggested to deteriorate over time. Unfortunately, previous studies did not integrate both pulmonary and cardiac determinants of functional status. In addition, a comparison with the natural decrease in exercise capacity in healthy subjects (in both children and adults) is lacking. This single-center study aims to investigate the functional status in a cohort of Fontan patients in relation to time since Fontan completion and to identify its determinants, including cardiac characteristics and pulmonary characteristics. Eighty-five consecutive Fontan patients ≥10 years who performed adequate cardiopulmonary exercise testing (respiratory exchange ratio >1.01) were included. Mean time since Fontan completion was 15 ± 9 years (range 2 to 37 years). New York Heart Association functional class was I in 36 patients (42%), II in 41 patients (48%), and III in 8 patients (9%). Peak oxygen uptake during exercise (VO2 index) was 25.7 ± 7.9 ml/min/m(2) (58 ± 14% of predicted). New York Heart Association functional class and peak VO2 index both correlated with time since the Fontan operation; however, peak VO2 as percentage of predicted (VO2(pred)) did not. In multivariate analyses, peak VO2(pred) was independently associated with maximum heart rate, oxygen pulse at peak exercise, and forced expiratory volume in 1 second (R(2) = 0.579) but not with cardiac output in rest. In conclusion, the present data suggest that functional status in Fontan patients is impaired already shortly after Fontan completion, whereas its subsequent deterioration seems to follow the natural decline of aging. Furthermore, functional status in Fontan patients correlates with pulmonary function and cardiac functional parameters during exercise but not with conventional cardiac measurements at rest. Copyright © 2017. Published by Elsevier Inc.

  12. Docetaxel-induced photo-recall phenomenon.

    PubMed

    Droitcourt, Catherine; Le Hô, Hélêne; Adamski, Henri; Le Gall, François; Dupuy, Alain

    2012-08-01

    Photo-recall phenomenon is a phototoxic eruption occurring on areas of previous ultraviolet-induced solar erythema following a systemic administration of a drug. It has been mostly described with methotrexate but remains rare with other antineoplastic drugs. We describe a case of docetaxel-induced photo-recall skin rash in a woman treated for a non-small-cell lung cancer. Although the patient has refused to receive a second infusion, chemotherapy can be carried on with photoprotection and the use of topical and/or systemic corticosteroids. In contrast, radiation recall is a well-known reaction by oncologists, most of them may not be aware of a similar phenomenon called photo-recall phenomenon. Recognizing this entity may avoid misdiagnosing a drug allergy and should avoid inappropriate decisions of drug discontinuation.

  13. Circulation Systems on Microcomputers.

    ERIC Educational Resources Information Center

    Carlson, Gary

    1984-01-01

    Reports on the use of microcomputers in comprehensive library circulation systems. Topics covered include system requirements (reliability, completeness); determining circulation system needs (saving money, improving service, modernization); limitations of microcomputers (capacity, kinds of data stored, number of stations or terminals); system…

  14. How Circulation of Water Affects Freezing in Ponds

    ERIC Educational Resources Information Center

    Moreau, Theresa; Lamontagne, Robert; Letzring, Daniel

    2007-01-01

    One means of preventing the top of a pond from freezing involves running a circulating pump near the bottom to agitate the surface and expose it to air throughout the winter months. This phenomenon is similar to that of the flowing of streams in subzero temperatures and to the running of taps to prevent pipe bursts in winter. All of these cases…

  15. How Circulation of Water Affects Freezing in Ponds

    ERIC Educational Resources Information Center

    Moreau, Theresa; Lamontagne, Robert; Letzring, Daniel

    2007-01-01

    One means of preventing the top of a pond from freezing involves running a circulating pump near the bottom to agitate the surface and expose it to air throughout the winter months. This phenomenon is similar to that of the flowing of streams in subzero temperatures and to the running of taps to prevent pipe bursts in winter. All of these cases…

  16. Measurement of thermoacoustic convection heat transfer phenomenon

    NASA Technical Reports Server (NTRS)

    Parang, M.; Salah-Eddine, A.

    1983-01-01

    In this paper the results of an experimental investigation of thermoacoustic convection (TAC) heat transfer phenomenon in both zero-gravity and gravity environment are presented and compared with pure conduction heat transfer. The numerical solutions of the governing equations obtained by others for TAC heat transfer phenomenon are also discussed. The experimental results show that for rapid heating rate at a boundary, the contribution of TAC heat transfer to a gas could be significantly (one order of magnitude) higher than heat transfer rate from pure conduction. The results also show significantly reduced transient time in heat transfer processes involving thermoacoustic convective heat transfer mode in both space and gravity environment.

  17. Aging phenomenon of stabilized bismuth oxides

    SciTech Connect

    Jiang, N.; Buchanan, R.M.; Henn, F.E.G.; Marshall, A.F.; Stevenson, D.A. . Dept. of Materials Science and Engineering); Washsman, E.D. . Materials Research Center)

    1994-03-01

    Stabilized bismuth oxides exhibit a decay in conductivity when annealed at temperatures below 600 C. The authors refer to this phenomenon as aging and it is distinct from a conventional crystallographic phase transformation. This phenomenon is revealed by an endotherm from DSC thermal analysis and results in the formation of a superstructure observable by TEM diffraction patterns, yet no change in structure is observable by XRD. Since oxygen vacancies are the mobile defects responsible for ionic conductivity, the authors attribute the aging process to the ordering of oxygen vacancies by an order-disorder transition below [approximately]600 C.

  18. First time description of dismantling phenomenon

    PubMed Central

    Barrer, Laurence; Gimenez, Guy

    2015-01-01

    Dismantling is a complex psychic phenomenon, which is not easy to define, and little interest has been shown in the subject. The authors of this paper want to demonstrate that dismantling is the main defense mechanism in autism, bringing about de-consensus of senses. The effects perceived in a child with autistic disorder are passivity and lack of thought. The authors’ purpose here is to define the dismantled state and reveal its underlying process. This paper will therefore describe for the first time in literature, the dismantling phenomenon and will submit a metapsychological approach of this defense mechanism. PMID:25999871

  19. Feature extraction of arc tracking phenomenon

    NASA Technical Reports Server (NTRS)

    Attia, John Okyere

    1995-01-01

    This document outlines arc tracking signals -- both the data acquisition and signal processing. The objective is to obtain the salient features of the arc tracking phenomenon. As part of the signal processing, the power spectral density is obtained and used in a MATLAB program.

  20. Bullying: Description and Analysis of the Phenomenon

    ERIC Educational Resources Information Center

    Benitez, Juan Luis; Justicia, Fernando

    2006-01-01

    This article purports to present this Special Issue about Bullying and, at the same time, to introduce the phenomenon of bullying in order to facilitate readers an updated vision about the problem that will be worked from different perspectives by researchers from national and international scope. With this purpose, we present some controversial…

  1. Facilitated Communication: The Clinical and Social Phenomenon.

    ERIC Educational Resources Information Center

    Shane, Howard C., Ed.

    This text explains the phenomenon of facilitated communication (FC) from an empirical, data-based, and/or clinical perspective. It is not a how-to-facilitate text, but one that explores the clinical and sociological reality of FC. A common theme running through each of the papers in the book is the question of FC's legitimacy. The papers reveal…

  2. A Phenomenon of Overqualification in Personnel Psychology

    ERIC Educational Resources Information Center

    Fine, Saul; Nevo, Baruch

    2007-01-01

    This study examines the concept of overqualification as a phenomenon of nonlinearity in the upper deciles of the ability-performance relationship. In three job contexts (military, academic, and industrial), the ability-performance relationship is characterized by a strong linear component below the mean and a ceiling effect at various points above…

  3. LED's and the "Fluttering Heart" Phenomenon.

    ERIC Educational Resources Information Center

    Jewett, John W., Jr.

    1993-01-01

    Describes the nineteenth-century parlor trick entitled the Fluttering Heart phenomenon which uses a red heart on a bright blue background. Discusses theories concerning the apparent fluttering. Suggests doing the trick with a red light-emitting diode in a darkened room. (MVL)

  4. Return to the "Getting Better Phenomenon"

    ERIC Educational Resources Information Center

    Carley, Glenn

    2007-01-01

    A school social work intervention called the "Getting Better Phenomenon" is redesigned as a curriculum resource for eighth- and ninth-grade teachers. The activities in the curriculum represent a synergy of provincial learning expectations; academic assessment and evaluation structures; teacher-guided delivery of student-generated "course" content;…

  5. Bullying: Description and Analysis of the Phenomenon

    ERIC Educational Resources Information Center

    Benitez, Juan Luis; Justicia, Fernando

    2006-01-01

    This article purports to present this Special Issue about Bullying and, at the same time, to introduce the phenomenon of bullying in order to facilitate readers an updated vision about the problem that will be worked from different perspectives by researchers from national and international scope. With this purpose, we present some controversial…

  6. Facilitated Communication: The Clinical and Social Phenomenon.

    ERIC Educational Resources Information Center

    Shane, Howard C., Ed.

    This text explains the phenomenon of facilitated communication (FC) from an empirical, data-based, and/or clinical perspective. It is not a how-to-facilitate text, but one that explores the clinical and sociological reality of FC. A common theme running through each of the papers in the book is the question of FC's legitimacy. The papers reveal…

  7. LED's and the "Fluttering Heart" Phenomenon.

    ERIC Educational Resources Information Center

    Jewett, John W., Jr.

    1993-01-01

    Describes the nineteenth-century parlor trick entitled the Fluttering Heart phenomenon which uses a red heart on a bright blue background. Discusses theories concerning the apparent fluttering. Suggests doing the trick with a red light-emitting diode in a darkened room. (MVL)

  8. Concept "Medical Museum" as a Sociocultural Phenomenon

    ERIC Educational Resources Information Center

    Chizh, Nina V.; Slyshkin, Gennady G.; Zheltukhina, Marina R.; Privalova, Irina V.; Kravchenko, Olga A.

    2016-01-01

    The article examines the concept "medical museum" as a sociocultural phenomenon. The register of medical museums in Russia makes the material of research. The complex methods of analysis of the concept "medical museum" are used. The philosophical, historical, cultural, structural, communicative and semantic analysis is carried…

  9. [Raynaud's phenomenon in occupational vibration exposure].

    PubMed

    Letzel, S; Muttray, A

    2013-03-01

    A 34-year-old female stonemason was referred for expert opinion. The question at issue was, whether she suffered from vibration-induced white finger disease. She was exposed to high-frequency hand-arm vibrations for many years. She reported white finger attacks at the long fingers, which were associated with cold weather. Until this point, physical findings were normal. The cold water provocation test showed a slight delay of the rewarming for the long fingers of the right hand. The nailfold capillary microscopy was normal. The slight Raynaud's phenomenon was recognized as an occupational disease with a diagnosis of vibration-induced white finger disease. About three years later, the symptoms of the Raynaud's phenomenon had deteriorated, although the patient had finished working with vibrating tools. The cold water provocation test confirmed the deterioration. At this time, the patient had inflamed swellings of some joints caused by rheumatoid arthritis. The differential diagnosis of a Raynaud's phenomenon should include occupational causes. Occupational history is diagnostically indicative. If an occupational disease is assumed, a report must be filed. With respect to German social law, the deterioration of the Raynaud's phenomenon was caused by the rheumatoid arthritis, which is regarded as independent from the job. © Georg Thieme Verlag KG Stuttgart · New York.

  10. Systemic lupus erythematosus and Raynaud's phenomenon*

    PubMed Central

    Heimovski, Flavia Emilie; Simioni, Juliana A.; Skare, Thelma Larocca

    2015-01-01

    BACKGROUND Patients with systemic lupus erythematosus seem to belong to different serological and clinical subgroups of the disease. Genetic background can cause the appearance of these subgroups. OBJECTIVE To determine whether Brazilian patients who have systemic lupus erythematosus and Raynaud's phenomenon differ from those who do not. METHODS Retrospective analysis of 373 medical records of systemic lupus erythematosus patients studied for demographic, clinical and serological data. A comparative analysis was performed of individuals with and without RP. RESULTS There was a positive association between Raynaud's phenomenon and age at diagnosis (p=0.02), presence of anti-Sm (p=0.01) antibodies and anti-RNP (p<0.0001). Furthermore, a negative association was found between Raynaud's phenomenon and hemolysis (p=0.01), serositis (p=0.01), glomerulonephritis (p=0.0004) and IgM aCL (p=0.004) antibodies. CONCLUSION Raynaud's phenomenon patients appear to belong to a systemic lupus erythematosus subset with a spectrum of clinical manifestations located in a more benign pole of the disease. PMID:26734864

  11. Martian Atmospheric Circulation and Climate

    NASA Technical Reports Server (NTRS)

    Ingersoll, Andrew P.

    2003-01-01

    This proposal is focused on using Mars Global Surveyor (MGS) data and numerical models to address issues of atmospheric mixing of volatiles and aerosols, on defining the mean state of the atmosphere and the degree of variability, and on the processes which exchange volatiles and aerosols between the surface and atmosphere. Specifically, five areas of research were defined: In the first, we proposed to use TES data to examine the general circulation of the atmosphere both through retrieval of the residual circulation, and by comparison of the TES data with a Mars General Circulation Model (GCM). In the second, we proposed to look at synoptic and mesoscale atmospheric mixing processes (baroclinic storms, etc.) by combining TES and MOC Wide Angle data, and by employing a Mars Mesoscale Model. In the third section, we proposed to examine the record of the Martian atmospheric state provided by MGS, Viking, and Mariner 9 - as well as published ground-based observations - in order to assess the nature of interannual variability. In the forth section, we proposed to compare numerical models of the Martian water and dust cycles with TES and MOC data, specifically looking at water ice cloud distributions, dust distribution, etc. In the fifth section, we propose to use the mesoscale model to study the Mars Pathfinder Lander data. This work has now concluded its final of three years.

  12. Life as a planetary phenomenon: the colonization of Mars

    NASA Technical Reports Server (NTRS)

    Margulis, L.; Guerrero, R.

    1995-01-01

    Life is a planet-wide phenomenon in which its components incessantly move and interact. Life imperatively recycles its parts at the surface of the Earth in a chemical transformation and physical transport that depends utterly on the energy from a recent star, the Sun. Humanity, entirely dependent on other beings, plays a recent and relatively small part in the great phenomenon of life that transports and transforms the surface of the Earth. Our species accelerates but does not dominate the metabolism of the Earth system. Ironically, during the Apollo days of the sixties, fears were rampant that Martian or other extraterrestrial "germs" might "contaminate" our planet. After Viking, such fears are seen as the manifestation of cultural paranoia. The Viking missions complemented ground-based astronomical observation and yielded definitive evidence for the lack of life on the red planet. The Gaia hypothesis states that the surface temperature, composition of the reactive gases, oxidation state, alkalinity-acidity on today's Earth are kept homeorrhetically at values set by the sum of the activities of the current biota. Life, in other words, not only produces and maintains its immediate environment, but appears on Earth only as a planetary phenomenon. Since the natural tendency of all life is to grow exponentially to fill proximal volume, the question now "can life ecopoietically expand to Mars?" is entirely equivalent to the query of "can Gaia reproduce?".

  13. Genetic View on the Phenomenon of Combined Diseases in Man

    PubMed Central

    Freidin, M.B.

    2009-01-01

    In clinical medicine, the phenomenon of polypathy, as a particular object of investigation, was first put forth by French clinicians at the end of the 19th century through the "arthritismus" doctrine. In the first half of the 20th century, German paediatricians singled out "syntropias," which are combinations of diseases with common pathophysiological mechanisms, and "dystropias," which are diseases that rarely co-occur in one individual. In the present paper, syntropy/dystropy is defined as a natural generic nonrandom phenomenon with an evolutionary-genetic basis. The genes involved in the development of syntropy are called "syntropic genes," whereas the genes that co-participate in pathophysiological mechanisms and prevent the co-occurrence of particular phenotypes are called "dystropic genes." Prospects for studying the genetic basis of this phenomenon are highlighted. The publicly available database HuGENet can be used in order to identify syntropic genes, as will be shown as examples in an analysis of cardiovascular diseases. PMID:22649614

  14. Life as a planetary phenomenon: the colonization of Mars.

    PubMed

    Margulis, L; Guerrero, R

    1995-01-01

    Life is a planet-wide phenomenon in which its components incessantly move and interact. Life imperatively recycles its parts at the surface of the Earth in a chemical transformation and physical transport that depends utterly on the energy from a recent star, the Sun. Humanity, entirely dependent on other beings, plays a recent and relatively small part in the great phenomenon of life that transports and transforms the surface of the Earth. Our species accelerates but does not dominate the metabolism of the Earth system. Ironically, during the Apollo days of the sixties, fears were rampant that Martian or other extraterrestrial "germs" might "contaminate" our planet. After Viking, such fears are seen as the manifestation of cultural paranoia. The Viking missions complemented ground-based astronomical observation and yielded definitive evidence for the lack of life on the red planet. The Gaia hypothesis states that the surface temperature, composition of the reactive gases, oxidation state, alkalinity-acidity on today's Earth are kept homeorrhetically at values set by the sum of the activities of the current biota. Life, in other words, not only produces and maintains its immediate environment, but appears on Earth only as a planetary phenomenon. Since the natural tendency of all life is to grow exponentially to fill proximal volume, the question now "can life ecopoietically expand to Mars?" is entirely equivalent to the query of "can Gaia reproduce?"

  15. Statin escape phenomenon: Fact or fiction?

    PubMed Central

    Barkas, Fotios; Elisaf, Moses; Klouras, Eleftherios; Dimitriou, Theodora; Tentolouris, Nikolaos; Liberopoulos, Evangelos

    2017-01-01

    AIM To evaluate the presence of the so called “statin escape” phenomenon among hyperlipidemic subjects attending a lipid clinic. METHODS This was a retrospective analysis of 1240 hyperlipidemic individuals followed-up for ≥ 3 years. We excluded those individuals meeting one of the following criteria: Use of statin therapy at baseline visit, discontinuation of statin treatment at most recent visit, change in statin treatment during follow-up and poor compliance to treatment. Statin escape phenomenon was defined as an increase in low-density lipoprotein cholesterol (LDL-C) levels at the most recent visit by > 10% compared with the value at 6 mo following initiation of statin treatment. RESULTS Of 181 eligible subjects, 31% exhibited the statin escape phenomenon. No major differences regarding baseline characteristics were found between statin escapers and non-statin escapers. Both escapers and non-escapers had similar baseline LDL-C levels [174 (152-189) and 177 (152-205) mg/dL, respectively]. In comparison with non-escapers, statin escapers demonstrated lower LDL-C levels at 6 mo after treatment initiation [88 (78-97) mg/dL vs 109 (91-129) mg/dL, P < 0.05], but higher levels at the most recent visit [103 (96-118) mg/dL vs 94 (79-114) mg/dL, P < 0.05]. CONCLUSION These data confirm the existence of an escape phenomenon among statin-treated individuals. The clinical significance of this phenomenon remains uncertain. PMID:28261552

  16. Powerful Radio Burst Indicates New Astronomical Phenomenon

    NASA Astrophysics Data System (ADS)

    2007-09-01

    . "It was a bit of luck that the survey included some observations of the sky surrounding the clouds," Narkevic said. It was from those "flanking" observations that the mysterious radio burst appeared in the data. The burst of radio waves was strong by astronomical standards, but lasted less than five milliseconds. The signal was spread out, with higher frequencies arriving at the telescope before the lower frequencies. This effect, called dispersion, is caused by the signal passing through ionized gas in interstellar and intergalactic space. The amount of this dispersion, the astronomers said, indicates that the signal likely originated about three billion light-years from Earth. No previously-detected cosmic radio burst has the same set of characteristics. "This burst represents an entirely new astronomical phenomenon," Bailes said. The astronomers estimate on the basis of their results that hundreds of similar events should occur over the sky each day. "Few radio surveys have the necessary sensitivity to such short-duration bursts, which makes them notoriously difficult to detect with current instruments," added Crawford. The next generation of radio telescopes currently under development should be able to detect many of these bursts across the sky. Although the nature of the mysterious new object is unclear, the astronomers have some ideas of what may cause such a burst. One idea is that it may be part of the energy released when a pair of superdense neutron stars collide and merge. Such an event is thought by some scientists to be the cause of one type of gamma-ray burst, but the only radio emission seen so far from these has been from the long-lived "afterglow" that follows the original burst. Another, more exotic, candidate is a burst of energy from an evaporating black hole. Black holes, concentrations of mass so dense that not even light can escape their powerful gravity, can lose mass and energy through a process proposed by famed British physicist Stephen

  17. [Effect of 5 warm-hot nature Chinese drugs for promoting blood circulation and removing blood stasis on 5-HT, NE, and endocrine hormones of rats of cold coagulation and blood stasis syndrome].

    PubMed

    Wang, Peng; Fu, Xian-Jun; Zhou, Yang; Wang, Zhen-Guo

    2014-11-01

    To study the mechanism of warm-hot nature Chinese drugs (WHNCD) for promoting blood circulation and removing blood stasis (PBCRBS) for intervening model rats of cold coagulation and blood stasis syndrome (CCBSS). CCBSS rat model was set up in outbred SD rats using ice water immersion method. Totally 300 successfully modeled CCBSS rats were randomly divided into 5 groups according to the principle of balance weight, 60 in each group. Contents of triothyrone (T3), tetraiodothyroine (T4), progesterone (P), 5-hydroxytryptamine (5-HT), and noradrenalin (NE) were paralleledly detected in all groups. Then rats in each group were subdivided into 6 subgroups as the model group, the curcuma group, the Ligsticum Chuanxiong group, the safflower group, the Rhizoma Corydalis group, and the Olibanumg group. Besides, 5 normal control groups were set up for 5 indices, 50 rats in total. We need 70 rats (7 groups) to finish observing 1 index, 350 rats in total for 5 indices. Except those in the model group and the normal control group, rats were administered with corresponding decoction at 20 g crude drugs/kg body weight by gastrogavage, 3 mL each time, once daily for 7 successive days. Equal volume of normal saline was given to rats in the normal control group and the model group. Contents of T3, T4, P, 5-HT, and NE were detected before treatment and 1 week after treatment. Compared with before treatment in the same group, T3 increased in the Ligsticum Chuanxiong group and the Olibanumg group, 5-HT increased in the Ligsticum Chuanxiong group, T4, NE, and P increased in all medicated groups (P < 0.05). Compared with the normal control group, contents of T3, T4, 5-HT, NE, and P in the model group decreased (P < 0.05). Compared with the model group, contents of T3, T4, 5-HT, and NE increased in each medicated group (P < 0.05). There was statistical difference in contents of P between the Ligsticum Chuanxiong group and the Olibanumg group (P < 0.05). WHNCD for PBCRBS had regulatory

  18. Endoscopic thoracic sympathicotomy for Raynaud's phenomenon.

    PubMed

    Matsumoto, Yasushi; Ueyama, Takeshi; Endo, Masamitsu; Sasaki, Hisao; Kasashima, Fuminori; Abe, Yoshinobu; Kosugi, Ikuko

    2002-07-01

    For many years, thoracic sympathectomy via open surgery was not used to treat Raynaud's phenomenon because of the invasiveness of this procedure and the poor long-term outcomes associated with it. However, with the introduction of endoscopic surgery, thoracic sympathectomy (or sympathicotomy) has been performed by some surgeons as a less invasive surgical option for patients with Raynaud's phenomenon. The less invasive procedure has the possibility of emphasizing merits of sympathectomy. The purpose of this study was to reevaluate the efficacy of sympathicotomy for Raynaud's phenomenon with endoscopic technique and its range of applicability. Between December 1992 and August 2001, endoscopic thoracic sympathicotomy (ETS) was performed in 28 patients with Raynaud's phenomenon (of a total of 502 patients with autonomic disorders who underwent ETS) at National Kanazawa Hospital. We considered indications for surgical treatment of Raynaud's phenomenon to include severe chronic symptoms or nonhealing digital ulceration refractory to intensive medical therapy. All patients were mailed a self-assessment questionnaire after surgery to determine the immediate and long-term results of the procedure. Data from both initial and long-term follow-up examinations were obtained. Fifty-four ETS procedures were performed in 28 patients. No operative mortality was seen, and no occurrence of major complications necessitated open surgery. Initial resolution or improvement of symptoms was achieved in 26 of 28 patients (92.9%). However, later in the postoperative period, symptoms recurred in 23 of 28 patients (82.1%), although no recurrence of digital ulceration was seen throughout our observation. At the final follow-up examination (median follow-up period, 62.5 months), 25 patients (89.3%) reported overall improvement of the frequency and severity of their symptoms. Despite the high rate of recurrence, ETS clearly produced a high rate of initial relief. ETS did indeed promote healing

  19. Circulating serotonin in vertebrates.

    PubMed

    Maurer-Spurej, E

    2005-08-01

    The role of circulating serotonin is unclear and whether or not serotonin is present in the blood of non-mammalian species is not known. This study provides the first evidence for the presence of serotonin in thrombocytes of birds and three reptilian species, the endothermic leatherback sea turtle, the green sea turtle and the partially endothermic American alligator. Thrombocytes from a fresh water turtle, American bullfrog, Yellowfin tuna, and Chinook salmon did not contain serotonin. Serotonin is a vasoactive substance that regulates skin blood flow, a major mechanism for endothermic body temperature regulation, which could explain why circulating serotonin is present in warm-blooded species. The temperature sensitivity of human blood platelets with concomitant changes in serotonin content further supports a link between circulating serotonin and thermoregulation. Phylogenetic comparison of the presence of circulating serotonin indicated an evolutionary divergence within reptilian species that might coincide with the emergence of endothermy.

  20. [Cannulae for extracorporeal circulation].

    PubMed

    Fukuda, Ikuo; Yanaoka, H

    2009-07-01

    Since the advent of extracorporeal circulation in 1954, its technique has developed rapidly owing to the progress of technology. Although it facilitated better outcome of cardiac surgery, lack of knowledge and malpractice of extracorporeal circulation may lead to serious complications. This article introduces different types of cannulae and their hydrodynamics during extracorporeal circulation. Characteristics of cannulae for extracorporeal circulation are described from viewpoints of material, requirements and technological background. Arterial perfusion cannulae have various flow patterns and affect shear stress on the aortic wall depending on the shape of each cannula exit. Technological background of venous drainage is also described. As a cardiovascular surgeon, it is important to understand the characteristics of each cannula in order to accomplish successful operation. Safe and effective means of providing sufficient arterial inflow in the presence of extensive aortic disease, such as atherosclerosis with aneurysm or dissections needs to be solved.

  1. Structural Determination of Circulation.

    ERIC Educational Resources Information Center

    Blankenburg, William B.

    1981-01-01

    Analyzes the effects of both structural factors (demographics, economic conditions, and competition) and discretionary factors (content, design, and marketing techniques) and concludes that it is the former that determine a newspaper's circulation. (FL)

  2. Island-trapped Waves, Internal Waves, and Island Circulation

    DTIC Science & Technology

    2015-09-30

    model of the depth-integrated flow for the world ocean allowing for island circulations . Geophys. Astrophys. Fluid Dyn., 45:89–112, 1989. J. MacKinnon...Mountain waves in the deep ocean . Nature, 501:321–322, 2013. M. Nikurashin and R. Ferrari. Overturning circulation driven by breaking internal waves...Island-trapped waves, internal waves, and island circulation T. M. Shaun Johnston Scripps Institution of Oceanography University of California

  3. Single transistor latch phenomenon in junctionless transistors

    NASA Astrophysics Data System (ADS)

    Singh Parihar, Mukta; Ghosh, Dipankar; Kranti, Abhinav

    2013-05-01

    In this work, we report on the single transistor latch phenomenon in junctionless transistors. In the latch condition, the device is unable to turn-off despite a reduction in gate bias. It is shown that impact ionization induced latch condition can occur due to an increase in drain bias, silicon film thickness, gate oxide thickness, and doping concentration. The latch phenomenon is explained in terms of generation-recombination rates, electrostatic potential, electric field distribution and product of current density and electric field (J.E). As latch condition is undesirable for dynamic memory applications, the work highlights the significance of (J.E) as a performance metric to avoid the junctionless transistor being driven into the latch mode.

  4. The phenomenon of fluorescence in immunosensors.

    PubMed

    Kłos-Witkowska, Aleksandra

    2016-01-01

    The phenomenon of fluorescence in immunosensors is described in this paper. Both structure and characteristics of biosensors and immunosensors are presented. Types of immunosensors and the response of bioreceptor layers to the reaction with analytes as well as measurements of electrochemical, piezoelectric and optical parameters in immunosensors are also presented. In addition, detection techniques used in studies of optical immunosensors based on light-matter interactions (absorbance, reflectance, dispersion, emission) such as: UV/VIS spectroscopy, reflectometric interference spectroscopy (RIfs), surface plasmon resonance (SPR), optical waveguide light-mode spectroscopy (OWLS), fluorescence spectroscopy. The phenomenon of fluorescence in immunosensors and standard configurations of immunoreactions between an antigen and an antibody (direct, competitive, sandwich, displacement) is described. Fluorescence parameters taken into account in analyses and fluorescence detection techniques used in research of immunosensors are presented. Examples of immunosensor applications are given.

  5. Phase transition phenomenon: A compound measure analysis

    NASA Astrophysics Data System (ADS)

    Kang, Bo Soo; Park, Chanhi; Ryu, Doojin; Song, Wonho

    2015-06-01

    This study investigates the well-documented phenomenon of phase transition in financial markets using combined information from both return and volume changes within short time intervals. We suggest a new measure for the phase transition behaviour of markets, calculated as a return distribution conditional on local variance in volume imbalance, and show that this measure successfully captures phase transition behaviour under various conditions. We analyse the intraday trade and quote dataset from the KOSPI 200 index futures, which includes detailed information on the original order size and the type of each initiating investor. We find that among these two competing factors, the submitted order size yields more explanatory power on the phenomenon of market phase transition than the investor type.

  6. Introduction to the B[e] Phenomenon

    NASA Astrophysics Data System (ADS)

    Oudmaijer, R. D.; Miroshnichenko, A. S.

    2017-02-01

    In this contribution we introduce the topic of this workshop with a brief history of studies of objects with the B[e] phenomenon, including its discovery and evolution of our understanding of the phenomenon. We will also review the most prominent results on selected objects published prior to the previous B[e] star conference in 2005. These include the discovery of B[e] supergiants in the Magellanic Clouds, detection of maser and laser lines in the spectrum of MWC 349A, studies of η Carinae, and a few more. This talk is planned to set up the stage for discussion of more recent results that will be presented at the conference.

  7. Lorentz Symmetry as AN Emergent Phenomenon

    NASA Astrophysics Data System (ADS)

    Consoli, M.

    2015-01-01

    The vacuum of quantum gravity is believed to be a form of `space-time foam' which resembles a turbulent fluid. In this perspective, it is conceivable that Lorentz symmetry might be an emergent phenomenon. However, this idea of an underlying turbulent ether is not strictly peculiar of quantum gravity. This general picture suggests an alternative interpretation of the stochastic signal observed in the present ether-drift experiments with potentially important implications for both relativity and gravity.

  8. Glomus Tumor Presenting as Raynaud's Phenomenon

    PubMed Central

    Abdelrahman, M. H.; Hammoudeh, M.

    2012-01-01

    Glomus tumors are rare tumors that often include hands and feet; they present characteristically with paroxysmal pain, exquisite point tenderness, and cold sensitivity. Such diagnosis needs to be confirmed by imaging like ultrasound and magnetic resonance imaging (MRI). Surgical excision is the treatment of choice for glomus tumors. There are only few case reports of glomus tumors in association with Raynaud's phenomenon; this is considered to be the 4th case. PMID:22811722

  9. The feedback phenomenon applied to underwater acoustics

    NASA Astrophysics Data System (ADS)

    Roux, Philippe; Jordan, Jason E.; Kuperman, W. A.

    2002-11-01

    People are familiar with the feedback phenomenon that results in the loud sound heard when a musician plays an electric instrument directly into a speaker. Feedback occurs when a source and a receiver are connected both acoustically through the propagation medium and electrically through an amplifier in such way that the received signal is simultaneously and continuously added to the emitted signal. A resonance is then obtained when the emitter and the receiver are in phase. The resonant frequency appears to be highly sensitive to fluctuations of the propagation medium. The feedback phenomenon has been experimentally demonstrated as a means to monitor the temperature fluctuation of a shallow water environment [''Acoustic monitoring of the sea medium variability: experimental testing of new methods,'' by A. V. Furduev, Acoust. Phys. 47, No. 3, 361-368 (2001)]. The goal of our work is to reproduce the feedback experiment using an alternative method that decomposes the feedback phenomenon into an iterative process. Successful reproduction of the feedback is accomplished using a step-by-step algorithm which details the evolution of the system from the initial signal to its steady-state form. These experimental and numerical results illustrate the potential of the feedback process for use in narrow-band acoustical tomography.

  10. Trance and the trickster: hypnosis as a liminal phenomenon.

    PubMed

    Krippner, Stanley

    2005-04-01

    This paper makes the case that hypnotic phenomena are liminal in nature and that hypnotic practitioners (such as Milton Erickson) share many traits with traditional societies' "tricksters." The ambiguous nature of hypnosis has been apparent since the days of Mesmer's animal magnetism. Hypnotized people often report hallucinations that confound their ordinary distinctions between reality and illusion, external and internal processes, and many other binary oppositions, including time and space as well as mind and body. In addition, hypnosis can obscure the distinction between fact and fiction in one's memory, as is evident in the "recovered memory" controversy. The role played by imagination is central to both indigenous rituals and hypnosis, and hypnosis is a multifaceted phenomenon requiring explanation at multiple levels. Some investigators and practitioners have missed the importance of the social context in which hypnosis occurs, while others have come close to destroying the most interesting and useful hypnotic phenomena under the guise of objectivity.

  11. Mechanisms of the warm-up phenomenon.

    PubMed

    Tomai, F; Crea, F; Danesi, A; Perino, M; Gaspardone, A; Ghini, A S; Cascarano, M T; Chiariello, L; Gioffrè, P A

    1996-07-01

    The warm-up phenomenon, described in patients with coronary artery disease, refers to the improved performance following a first exercise test. The aim of this study was to investigate the causes of the warm-up phenomenon. Fifteen patients with coronary artery disease and positive exercise test were enrolled. Patients were off treatment throughout the study. They underwent two consecutive treadmill exercise tests according to the Bruce protocol, with a recovery period of 10 min to re-establish baseline conditions. A third exercise test was then performed 2 h later. Before the onset of ischaemia, the rate-pressure product for a similar degree of workload was similar during the first and second exercise test, while it was lower during the third test (P < 0.05). Time to 1.5 mm ST-segment depression during the second and third exercise test was greater than during the first test (454 +/- 133 and 410 +/- 161 vs 354 +/- 127 s, P < 0.01, respectively). Similarly, the time to anginal pain onset was increased during the second and third exercise tests, compared to the first test (356 +/- 208 and 310 +/- 203 vs 257 +/- 204 s, P < 0.01, respectively). In contrast, rate-pressure product at 1.5 mm ST-segment depression during the second test was higher than that during the first test (232 +/- 47 vs 210 +/- 39 beats.min-1.mmHg.10(2), P < 0.01), while in the third test it was similar to that during the first (209 +/- 43 beats.min-1.mmHg.10(2), P = ns). The warm-up phenomenon observed a few minutes after exercise is characterized by an increase of both time to ischaemia and ischaemic threshold; this adaptation to ischaemia may be due to an improvement of myocardial perfusion or to preconditioning. Conversely, the warm-up phenomenon observed a few hours after repeated exercise is characterized by an increase of time to ischaemia but not of ischaemic threshold and is caused by a slower increase of cardiac workload. Thus, the mechanisms of the warm-up phenomenon may be different

  12. MHD Dynamo phenomenon in our lab (Petrus Peregrinus Medal Lecture)

    NASA Astrophysics Data System (ADS)

    Gailitis, Agris

    2016-04-01

    Celestial objects generate magnetic field very like technical dynamo do. Field induces current in a moving electroconductor. The induced current amplifies magnetic field. At large enough product conductivity time's velocity time's size amplification exceeds losses and situation without magnetic field is impossible. Such scenario is obvious for technical dynamo made from insolated wire but not so for uniform conductor as in celestial bodies. Development of the idea took literally the entire 20th century. Discovery of sunspot magnetic fields at the century rise and laboratory verification at the very fall. At thirties Cowling noticed that geometrically simple shaped (axially symmetrical) field can't sustain itself. Process must be more complex, somehow spatially fragmented. At the middle of century Parker and Steenbeck saw such fragmentation in a turbulent structure of hydrodynamic flow. Shortly after his α-effect approach was made ready Steenbeck invited us to think on molten Na experiments for theory verification. The first idea was to push the Na flow through the hand-blown pipe maze. Similar industrial scale experiment after years and regardless of us was realized in Karlsruhe. Seeking for something cheaper we stopped at Ponomarenko idea - axially symmetric helical flow can't generate axi-simmetric field but it can generate azimuthally structured one. The mathematical model was modified to experimental conditions and numerically optimized. The Dynamo stand was built and it works. Even after optimization Dynamo stand exceeds usual size of hydraulic experiments. 2m3 of molten Na circulate there by means of propeller powered from 200kW motor. When circulation exceeds 0.6 m3/s (at 120°C) seemingly from nowhere appears magnetic field. Twisted field pattern slowly (about 1.5Hz) rotates round flow axis. Up to 0.1T field stay as long as stay circulation and temperature. When sodium is heated up or slowed down the field is slowly dying out. Phenomenon is much richer

  13. Common Era Hydroclimate and Atmospheric Circulation in the Western Mediterranean Basin

    NASA Astrophysics Data System (ADS)

    Touchan, R.; Anchukaitis, K. J.; Shishov, V. V.; Kherchouche, D.; Slimani, S.; Ilmen, R.; Hasnaoui, F.; Guibal, F.; Camarero, J. J.; Salguero, R. S.; Piermattei, A.; Sesbou, A.; Meko, D. M.; Cook, B. I.; Sabir, M.

    2016-12-01

    Drought phenomenon in the Mediterranean Basin, including North Africa and the western Mediterranean, has an impact on all segments of society and all economic sectors. To understand contemporary patterns and causes of drought in these regions, it is necessary to understand natural climate variability over the Common Era. Here, we use a network of tree-ring proxies spanning up to a millennium to understand and reconstruct both large-scale Atlantic circulation changes and regional hydroclimate. Eighty-five chronologies across the region show a variable but coherent response to winter-spring precipitation mediated by geography and topography. Reconstructions using this network of spatiotemporal drought variability as well as a new reconstruction of the North Atlantic Oscillation put the past, present, and future climate variability of the region into a long-term Common Era context.

  14. Optical Rankine Vortex and Anomalous Circulation of Light

    SciTech Connect

    Swartzlander, Grover A. Jr.; Hernandez-Aranda, Raul I.

    2007-10-19

    Rankine vortex characteristics of a partially coherent optical vortex are explored using classical and physical optics. Unlike a perfectly coherent vortex mode, the circulation is not quantized. Excess circulation is predicted owing to the wave nature of composite vortex fields. Based on these findings, we propose a vortex stellar interferometer.

  15. Library Circulation Systems -- An Overview.

    ERIC Educational Resources Information Center

    Surace, Cecily J.

    The model circulation system outlined is an on-line real time system in which the circulation file is created from the shelf list and the terminal inquiry system includes the capability to query and browse through the bibliographic system and the circulation subsystem together to determine the availability for circulation of specific documents, or…

  16. Ocean circulation using altimetry

    NASA Technical Reports Server (NTRS)

    Minster, Jean-Francois; Brossier, C.; Gennero, M. C.; Mazzega, P.; Remy, F.; Letraon, P. Y.; Blanc, F.

    1991-01-01

    Our group has been very actively involved in promoting satellite altimetry as a unique tool for observing ocean circulation and its variability. TOPEX/POSEIDON is particularly interesting as it is optimized for this purpose. It will probably be the first instrument really capable of observing the seasonal and interannual variability of subtropical and polar gyres and the first to eventually document the corresponding variability of their heat flux transport. The studies of these phenomena require data of the best quality, unbiased extraction of the signal, mixing of these satellite data with in situ measurements, and assimilation of the whole set into a dynamic description of ocean circulation. Our group intends to develop responses to all these requirements. We will concentrate mostly on the circulation of the South Atlantic and Indian Oceans: This will be done in close connection with other groups involved in the study of circulation of the tropical Atlantic Ocean, in the altimetry measurements (in particular, those of the tidal issue), and in the techniques of data assimilation in ocean circulation models.

  17. On the North Atlantic circulation

    SciTech Connect

    Schmitz, W.J. Jr.; McCartney, M.S. )

    1993-02-01

    A summary for North Atlantic circulation is proposed to replace the circulation scheme hypothesized by Worthington in 1976. Divergences from the previous model are in thermohaline circulation, cross-equatorical transport and Florida Current sources, flow in the eastern Atlantic, circulation in the Newfoundland Basin, slope water currents, and flow pattern near the Bahamas. The circulation patterns presented here are consistent with the majority of of published accounts of flow components. 77 refs., 14 figs., 3 tabs.

  18. Stochastic mirage phenomenon in a random medium.

    PubMed

    McDaniel, Austin; Mahalov, Alex

    2017-05-15

    In the framework of geometric optics, we consider the problem of characterizing the ray trajectory in a random medium with a mean refractive index gradient. Such a gradient results in the mirage phenomenon where an object's observed location is displaced from its actual location. We derive formulas for the mean ray path in both the situation of isotropic stochastic fluctuations and an important anisotropic case. For the isotropic model, the mean squared displacement is also given by a simple formula. Our results could be useful for applications involving the propagation of electromagnetic waves through the atmosphere, where larger-scale mean gradients and smaller-scale stochastic fluctuations are both present.

  19. Impact process: an important geological phenomenon.

    PubMed

    Skala, R

    1996-01-01

    The impact process was for a long period of time, even after a wider acceptance among the geological community, considered to be a marginal phenomenon in the Earth sciences. The first decade or two have showed an importance of the process itself and consequent events only too clearly. The present paper is a review describing the history and development of the impact hypothesis, structure and origin of impact craters, influence of huge impacts on the living environment and other aspects of the impact process from the point of view of geology s.l.

  20. Is iloprost effective in secondary Raynaud's phenomenon?

    PubMed

    Lustig, Nicole; Rada, Gabriel

    2015-03-09

    Patients with systemic sclerosis frequently have Raynaud's phenomenon and digital ischemic ulcers. Iloprost, a synthetic prostacyclin analogue, may be effective in these cases. Searching in Epistemonikos database, which is maintained by screening 20 databases, we identified three systematic reviews including seven randomized trials. We combined the evidence using meta-analysis and generated a summary of findings table following the GRADE approach. We concluded iloprost may lead to little or no difference in the frequency or severity of secondary Raynaud, and it is associated to adverse effects and important costs.

  1. Experimental investigations of the ozone zero phenomenon

    NASA Astrophysics Data System (ADS)

    Murayama, K.; Matsumura, N.; Taguchi, M.; Katoh, Y.; Teranishi, K.; Suzuki, S.; Itoh, H.

    2009-08-01

    An experimental study is carried out to clarify the mechanism of the ozone zero phenomenon. Temporal variations of both the discharge characteristics and the metallic electrode surface in the ozone generator are investigated by the Lissajous figure method and Auger electron spectroscopy (AES), respectively. The AES results suggest that a number of oxygen atoms penetrate into the stainless-steel electrode owing to the exposure to ozone. Such a surface change would result in the temporal variation of the discharge characteristics of the generator.

  2. Storage-recovery phenomenon in magnonic crystal.

    PubMed

    Chumak, A V; Vasyuchka, V I; Serga, A A; Kostylev, M P; Tiberkevich, V S; Hillebrands, B

    2012-06-22

    The phenomenon of coherent wave trapping and restoration is demonstrated experimentally in a magnonic crystal. Unlike the conventional scheme used in photonics, the trapping occurs not due to the deceleration of the incident wave when it enters the periodic structure but due to excitation of the quasinormal modes of the artificial crystal. This excitation occurs at the group velocity minima of the decelerated wave in narrow frequency regions near the edges of the band gaps of the crystal. The restoration of the traveling wave is implemented by means of phase-sensitive parametric amplification of the stored mode.

  3. Investigation of Buckling Phenomenon Induced by Growth of Vertebral Bodies Using a Mechanical Spine Model

    NASA Astrophysics Data System (ADS)

    Sasaoka, Ryu; Azegami, Hideyuki; Murachi, Shunji; Kitoh, Junzoh; Ishida, Yoshito; Kawakami, Noriaki; Makino, Mitsunori; Matsuyama, Yukihiro

    A hypothesis that idiopathic scoliosis is a buckling phenomenon of the fourth or sixth mode, which is the second or third lateral bending mode, induced by the growth of vertebral bodies was presented in a previous paper by the authors using numerical simulations with a finite-element model of the spine. This paper presents experimental proof of the buckling phenomenon using mechanical spine models constructed with the geometrical data of the finite-element model used in a previous work. Using three spine mechanical models with different materials at intervertebral joints, the change in the natural vibration eigenvalue of the second lateral bending mode with the growth of vertebral bodies was measured by experimental modal analysis. From the result, it was observed that natural vibration eigenvalue decreased with the growth of vertebral bodies. Since the increase in primary factor inducing the buckling phenomenon decreases natural vibration eigenvalue, the obtained result confirms the buckling hypothesis.

  4. Transverse ageostrophic circulations associated with elevated mixed layers

    NASA Technical Reports Server (NTRS)

    Keyser, D.; Carlson, T. N.

    1984-01-01

    The nature of the frontogenetically forced transverse ageostrophic circulations connected with elevated mixed layer structure is investigated as a first step toward diagnosing the complex vertical circulation patterns occurring in the vicinity of elevated mixed layers within a severe storm environment. The Sawyer-Eliassen ageostrophic circulation equation is reviewed and applied to the elevated mixed layer detected in the SESAME IV data set at 2100 GMT of May 9, 1979. The results of the ageostrophic circulation diagnosis are confirmed and refined by considering an analytic specification for the elevated mixed layer structure.

  5. Atmospheric circulation of Venus

    NASA Technical Reports Server (NTRS)

    Rossow, W. B.

    1985-01-01

    Observational data of Venus are utilized to study rotational effects on atmospheric circulations. The high surface temperature and planetary-scale turbulent motion at cloud tops, and the relation between energy and momentum budget are examined. The limited amount of data available on the vertical and horizontal distribution of net radiative heating, the zonal wind structure, and waves affects the study of the temperature and motion on Venus. The limitations of the scaling analysis used to estimate the properties of the circulation as regards the cyclostrophic balance, the extent of the Hadley circulation, large-scale wave transport, vertical propagation of waves, convection, and turbulence are considered. Hypotheses concerned with the deep, cloud-level, and upper atmospheres of Venus are proposed. Future research in the areas of propagating planetary- scale waves, zonal flow and planetary-scale wave instability processes, and convection is suggested.

  6. Why do metabolites circulate?

    PubMed

    Smith, Dennis A; Dalvie, Deepak

    2012-01-01

    The aim of most metabolism and excretion processes is to remove the drug and drug related material from the body; however, in most cases metabolites are present in abundance in circulation. To allow better in vitro/in vivo correlations a greater understanding of why metabolites formed in organs such as the liver are present in the circulation is necessary. Separating metabolites into highly lipid permeable and low lipid permeable allows the role of passive efflux from the liver and active transport to be dissected. Many drugs form glucuronide metabolites that circulate at high total concentrations and attention is drawn to low lipid permeability, efflux from the liver by MRP3, high plasma protein binding and restricted distribution as the explanation for this. The use of metabolite maps is suggested as a way of displaying complex processes in a simple form.

  7. 40 CFR 230.23 - Current patterns and water circulation.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... Potential Impacts on Physical and Chemical Characteristics of the Aquatic Ecosystem § 230.23 Current... water in the aquatic ecosystem. Currents and circulation respond to natural forces as modified by basin...

  8. 40 CFR 230.23 - Current patterns and water circulation.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... Potential Impacts on Physical and Chemical Characteristics of the Aquatic Ecosystem § 230.23 Current... water in the aquatic ecosystem. Currents and circulation respond to natural forces as modified by basin...

  9. 40 CFR 230.23 - Current patterns and water circulation.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... Potential Impacts on Physical and Chemical Characteristics of the Aquatic Ecosystem § 230.23 Current... water in the aquatic ecosystem. Currents and circulation respond to natural forces as modified by basin...

  10. 40 CFR 230.23 - Current patterns and water circulation.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... Potential Impacts on Physical and Chemical Characteristics of the Aquatic Ecosystem § 230.23 Current... water in the aquatic ecosystem. Currents and circulation respond to natural forces as modified by basin...

  11. 40 CFR 230.23 - Current patterns and water circulation.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... Potential Impacts on Physical and Chemical Characteristics of the Aquatic Ecosystem § 230.23 Current... water in the aquatic ecosystem. Currents and circulation respond to natural forces as modified by basin...

  12. Acoustical phenomenon in ancient Totonac's monument

    NASA Astrophysics Data System (ADS)

    Sánchez-Dehesa, José; Ha˚Kansson, Andreas; Cervera, Francisco; Meseguer, Francisco; Manzanares-Martínez, Betsabé; Ramos-Mendieta, Felipe

    2004-05-01

    The circle of gladiators is a monument built by Totonac Indians in the ceremonial site of Cempoala, which is located near Veracruz (Mexico). The city is believed to date to around 1200 A.D. The monument is a round structure with crenellated wall tops, and it has a diameter of 13.4 m. Though the deterioration of this monument is noticeable, it presents a singular acoustical phenomenon whose strength had to be probably extraordinary on the date of its construction. In brief, along any diameter in the circle, one can find two focal points such that if one person speaks on one focus, another person located on the other hears the sound reinforced. In other words, this circular place acoustically behaves as if it were elliptical. Here, we report the experimental characterization of the phenomenon and present a theoretical explanation. Also, the intentionality of the Totonacs is speculated since these people are associated with the Mayan culture, which is known by its realizations of environments with astonishing sonic properties. [Work supported by CEAL-UAM of Spain.

  13. NANOLEAKAGE PHENOMENON ON DEPROTEINIZED HUMAN DENTIN

    PubMed Central

    Duarte, Patrícia de Britto Pereira Garcia; da Silva, Eduardo Moreira

    2007-01-01

    Objective: The purpose of this study was to evaluate the influence of dentin deproteinization on the nanoleakage phenomenon. Material and Methods: Class V cavities were prepared in 12 human molars with cervical margins located in dentin. The cavities were assigned to 2 groups (n=6) according to dentin treatment: Group I - dentin treated in accordance with the manufacturer’s instructions and Group II - dentin treated following the manufacturer’s instructions + 10% NaOCl. Each group was sub-divided into three groups, according to the DBS (dentin bonding system) used: Scotchbond Multi Purpose (SBMP), Prime & Bond NT (PB) and Clearfil SE Bond (SE), which were applied according to manufacturer’s instructions. The cavities were restored with composite resin, and the specimens were immersed in a tracer agent (AgNO3 50%) for 24 h. The teeth were sectioned buccolingually through the center of the restorations, and nanoleakage pattern was evaluated by scanning electron microscopy (SEM) using the backscattered electron image mode. Results: SEM analysis showed different nanoleakage patterns for each DBS. Irrespective of dentin treatments, all SBMP specimens showed nanoleakage. SE did not show any nanoleakage with both dentin treatments used. PB showed nanoleakage within the hybrid layer only in Group I. Conclusions: The influence of dentin deproteinization on the nanoleakage phenomenon was dependent on dentin bonding system formulation and bonding strategies. PMID:19089146

  14. Brugada phenocopy: A new electrocardiogram phenomenon

    PubMed Central

    Anselm, Daniel D; Evans, Jennifer M; Baranchuk, Adrian

    2014-01-01

    Brugada phenocopies (BrP) are clinical entities that are etiologically distinct from true congenital Brugada syndrome. BrP are characterized by type 1 or type 2 Brugada electrocardiogram (ECG) patterns in precordial leads V1-V3. However, BrP are elicited by various underlying clinical conditions such as myocardial ischemia, pulmonary embolism, electrolyte abnormalities, or poor ECG filters. Upon resolution of the inciting underlying pathological condition, the BrP ECG subsequently normalizes. To date, reports have documented BrP in the context of singular clinical events. More recently, recurrent BrP has been demonstrated in the context of recurrent hypokalemia. This demonstrates clinical reproducibility, thereby advancing the concept of this new ECG phenomenon. The key to further understanding the pathophysiological mechanisms behind BrP requires experimental model validation in which these phenomena are reproduced under strictly controlled environmental conditions. The development of these validation models will help us determine whether BrP are transient alterations of sodium channels that are not reproducible with a sodium channel provocative test or alternatively, a malfunction of other ion channels. In this editorial, we discuss the conceptual emergence of BrP as a new ECG phenomenon, review the progress made to date and identify opportunities for further investigation. In addition, we also encourage investigators that are currently reporting on these cases to use the term BrP in order to facilitate literature searches and to help establish this emerging concept. PMID:24669289

  15. Brugada phenocopy: A new electrocardiogram phenomenon.

    PubMed

    Anselm, Daniel D; Evans, Jennifer M; Baranchuk, Adrian

    2014-03-26

    Brugada phenocopies (BrP) are clinical entities that are etiologically distinct from true congenital Brugada syndrome. BrP are characterized by type 1 or type 2 Brugada electrocardiogram (ECG) patterns in precordial leads V1-V3. However, BrP are elicited by various underlying clinical conditions such as myocardial ischemia, pulmonary embolism, electrolyte abnormalities, or poor ECG filters. Upon resolution of the inciting underlying pathological condition, the BrP ECG subsequently normalizes. To date, reports have documented BrP in the context of singular clinical events. More recently, recurrent BrP has been demonstrated in the context of recurrent hypokalemia. This demonstrates clinical reproducibility, thereby advancing the concept of this new ECG phenomenon. The key to further understanding the pathophysiological mechanisms behind BrP requires experimental model validation in which these phenomena are reproduced under strictly controlled environmental conditions. The development of these validation models will help us determine whether BrP are transient alterations of sodium channels that are not reproducible with a sodium channel provocative test or alternatively, a malfunction of other ion channels. In this editorial, we discuss the conceptual emergence of BrP as a new ECG phenomenon, review the progress made to date and identify opportunities for further investigation. In addition, we also encourage investigators that are currently reporting on these cases to use the term BrP in order to facilitate literature searches and to help establish this emerging concept.

  16. The McGurk phenomenon in Italian listeners

    PubMed Central

    Bovo, R; Ciorba, A; Prosser, S; Martini, A

    2009-01-01

    Summary In the classic example of the McGurk effect, when subjects see a speaker say /ga/ and hear a simultaneous /ba/, they typically perceive /da/, a syllable that was not presented either acoustically, or visually. This phenomenon, although non-natural and recreated in laboratory investigations, has been studied in order to better understand how, where and when the central nervous system processes and integrates visual and auditory signals. Till now, it has been demonstrated for English, Spanish and German languages, while in Japanese and Chinese it seems weaker. Aim of this study was to evaluate the entity of the McGurk effect for the Italian language. Results obtained demonstrate a robust McGurk effect for the Italian language, which has never been described before. The phenomenon is highly significant when an auditory bilabial Consonant-Vowel is dubbed with a visual apico-dental or velar Consonant-Vowel. Results are discussed on the basis of the recent hypothesis regarding the bimodal perception. PMID:20161878

  17. Arctic circulation regimes

    PubMed Central

    Proshutinsky, Andrey; Dukhovskoy, Dmitry; Timmermans, Mary-Louise; Krishfield, Richard; Bamber, Jonathan L.

    2015-01-01

    Between 1948 and 1996, mean annual environmental parameters in the Arctic experienced a well-pronounced decadal variability with two basic circulation patterns: cyclonic and anticyclonic alternating at 5 to 7 year intervals. During cyclonic regimes, low sea-level atmospheric pressure (SLP) dominated over the Arctic Ocean driving sea ice and the upper ocean counterclockwise; the Arctic atmosphere was relatively warm and humid, and freshwater flux from the Arctic Ocean towards the subarctic seas was intensified. By contrast, during anticylonic circulation regimes, high SLP dominated driving sea ice and the upper ocean clockwise. Meanwhile, the atmosphere was cold and dry and the freshwater flux from the Arctic to the subarctic seas was reduced. Since 1997, however, the Arctic system has been under the influence of an anticyclonic circulation regime (17 years) with a set of environmental parameters that are atypical for this regime. We discuss a hypothesis explaining the causes and mechanisms regulating the intensity and duration of Arctic circulation regimes, and speculate how changes in freshwater fluxes from the Arctic Ocean and Greenland impact environmental conditions and interrupt their decadal variability. PMID:26347536

  18. Arctic circulation regimes.

    PubMed

    Proshutinsky, Andrey; Dukhovskoy, Dmitry; Timmermans, Mary-Louise; Krishfield, Richard; Bamber, Jonathan L

    2015-10-13

    Between 1948 and 1996, mean annual environmental parameters in the Arctic experienced a well-pronounced decadal variability with two basic circulation patterns: cyclonic and anticyclonic alternating at 5 to 7 year intervals. During cyclonic regimes, low sea-level atmospheric pressure (SLP) dominated over the Arctic Ocean driving sea ice and the upper ocean counterclockwise; the Arctic atmosphere was relatively warm and humid, and freshwater flux from the Arctic Ocean towards the subarctic seas was intensified. By contrast, during anticylonic circulation regimes, high SLP dominated driving sea ice and the upper ocean clockwise. Meanwhile, the atmosphere was cold and dry and the freshwater flux from the Arctic to the subarctic seas was reduced. Since 1997, however, the Arctic system has been under the influence of an anticyclonic circulation regime (17 years) with a set of environmental parameters that are atypical for this regime. We discuss a hypothesis explaining the causes and mechanisms regulating the intensity and duration of Arctic circulation regimes, and speculate how changes in freshwater fluxes from the Arctic Ocean and Greenland impact environmental conditions and interrupt their decadal variability. © 2015 The Authors.

  19. Circulation Aide Training Manual.

    ERIC Educational Resources Information Center

    Bergeson, Alan O.

    This training manual provides instruction on shelving and other duties for student assistants in the learning resources center at the College of Dupage, located in Illinois. It is noted that prospective student circulation aides are required to read the manual and pass a written test on policies and procedures before they are allowed to shelve…

  20. Portable oven air circulator

    DOEpatents

    Jorgensen, Jorgen A.; Nygren, Donald W.

    1983-01-01

    A portable air circulating apparatus for use in cooking ovens which is used to create air currents in the oven which transfer heat to cooking foodstuffs to promote more rapid and more uniform cooking or baking, the apparatus including a motor, fan blade and housing of metallic materials selected from a class of heat resistant materials.

  1. [Circulating tumor cells and advanced prostate cancer].

    PubMed

    Murez, Thibaut; Droupy, Stéphane; Rebillard, Xavier; Alix-Panabieres, Catherine

    2012-07-01

    Despite development and widespread of PSA, current tools evaluating prostate cancer still give inconsistent or insufficiently relevant results. As encouraging data raised from circulating tumor cells detection in colon or breast cancer, they were evaluated as a surrogate prostate cancer biomarker. Tumor cells need to leave their surrounding primary environment and to survive in mesenchymal environment before they spill and metastasize. Basic research revealed several mutations required through a complex transition phenomenon, including dormancy steps. Circulating cells detection techniques are based on molecular and immunologic methods. Most of them need an enrichment step to improve sensibility and/or specificity. As of today, Veridex' CellSearch is the only FDA approved technique in the evaluation of castration resistant prostate cancer response to new drugs. Clinical research using other techniques highlighted the need for clinical endpoints, as there's no relevant tool and as techniques' target differ. Further studies are required to improve circulating tumors cells' staging and prognosis value. Cellular characterization may be the way to identify metastasis development potential more than the spillage burden. Those techniques still need improvements before they are included in daily practice decisional trees.

  2. The aerodynamics of circulation control

    NASA Technical Reports Server (NTRS)

    Wood, N. J.

    1981-01-01

    Two dimensional subsonic wind tunnel tests were conducted on a 20% thickness: chord ratio circulation controlled elliptic aerofoil section equipped with forward and reverse blowing slots. Overall performance measurements were made over a range of trailing edge blowing momentum coefficients from 0 to 0.04; some included the effect of leading edge blowing. A detailed investigation of the trailing edge wall jet, using split film probes, hot wire probes and total head tubes, provided measurements of mean velocity components, Reynolds normal and shear stresses, and radial static pressure. The closure of the two dimensional angular momentum and continuity equations was examined using the measured data, with and without correction, and the difficulty of obtaining a satisfactory solution illustrated. Suggestions regarding the nature of the flow field which should aid the understanding of Coanda effect and the theoretical solution of highly curved wall jet flows are presented.

  3. Dependence phenomenon analysis of the stock market

    NASA Astrophysics Data System (ADS)

    Cheng, Wuyang; Wang, Jun

    2013-04-01

    A random financial stock price model is developed by the interacting contact process, which is one of the statistical-physics systems. The contact process is a continuous-time Markov process, one interpretation of this process is as a model for the spread of an infection, where the epidemic spreading mimics the interplay of local infections and the recovery of individuals. We investigate and analyze the long-term memory, the nonlinear correlations and the multifractal phenomenon of normalized returns of the price model by statistical analysis methods, which include autocorrelation analysis, the Gaussian copula method and the multifractal analysis method. Moreover, we consider the daily returns of the Shanghai Stock Exchange Composite Index and the Shenzhen Stock Exchange Composite Index, and the comparisons of statistical behaviors of returns between the actual data and the simulation data are presented.

  4. [Dynamic wallpaper phenomenon and fusional hysteresis].

    PubMed

    Kondo, M; Nakamizo, S

    1982-12-01

    Two experiments were conducted with six and three subjects, respectively, to examine the "dynamic" wallpaper phenomenon in which the apparent location of a uniform repeating pattern shifted abruptly at a certain convergence distance when the pattern was viewed with the gradual change of convergence. Experiment 1 demonstrated that the critical convergence distances (shift points), at which the apparent location of the pattern shifted, differed between the two directions of the change of convergence, converging and diverging. It was greater in the diverging condition than in the converging condition. This fact shows a tendency to keep the same fusional state as far as possible when the convergence changes gradually. Experiment 2 showed that the difference of the critical convergence distance between the converging and diverging conditions is systematically related to the convergence level, that is, the difference increased as the convergence angle increased. The implications of the results of the two experiments were discussed in the context of the fusional hysteresis.

  5. The Phenomenon of the Urban Mummy.

    PubMed

    Harding, Brett E; Wolf, Barbara C

    2015-11-01

    The environmental mummification of a body in an urban setting is an unusual event. Florida is known for its high temperatures and humidity, which typically result in the rapid putrefaction of bodies. However, under certain circumstances, Florida's climate provides an environment suitable for mummification, typically in isolated areas. We previously reported a case of a homicide/suicide in a residential neighborhood in which the mummified remains were undetected for several years. We have subsequently encountered two additional cases in which mummified bodies were discovered in urban settings. Presented in the historical context of the environmental conditions and postmortem processes involved in mummification, these cases illustrate the particular constellation of human behaviors and scenarios, as well as environmental conditions, which must coincide for this phenomenon to occur and highlight the necessity of the multidisciplinary approach to the medicolegal investigation of such deaths and the determination of the cause and manner of death. © 2015 American Academy of Forensic Sciences.

  6. [Electroencephalographic characteristics of the deja vu phenomenon].

    PubMed

    Vlasov, P N; Cherviakov, A V; Gnezdinsiĭ, V V

    2013-01-01

    Déjà vu (DV, from French "already seen") is an aberration of psychic activity associated with transitory erroneous perception of novel circumstances, objects, or people as already known. An aim of the study was to investigate EEG characteristics of DV in patients with epilepsy. We studied 166 people (63.2% women, mean age 25.17±9.19 years). The DV phenomenon was studied in patients (27 people) and in a control group (139 healthy people). Patients were interviewed for DV characteristics and underwent a long (12-16 h) ambulatory EEG-monitoring study. In EEG, DV episodes in patients began with polyspike activity in the right temporal lobe and, in some cases, ended with the slow-wave theta-delta activity in the right hemisphere.

  7. Evolution as a self-organized critical phenomenon.

    PubMed Central

    Sneppen, K; Bak, P; Flyvbjerg, H; Jensen, M H

    1995-01-01

    We present a simple mathematical model of biological macroevolution. The model describes an ecology of adapting, interacting species. The environment of any given species is affected by other evolving species; hence, it is not constant in time. The ecology as a whole evolves to a "self-organized critical" state where periods of stasis alternate with avalanches of causally connected evolutionary changes. This characteristic behavior of natural history, known as "punctuated equilibrium," thus finds a theoretical explanation as a self-organized critical phenomenon. The evolutionary behavior of single species is intermittent. Also, large bursts of apparently simultaneous evolutionary activity require no external cause. Extinctions of all sizes, including mass extinctions, may be a simple consequence of ecosystem dynamics. Our results are compared with data from the fossil record. Images Fig. 3 Fig. 6 Fig. 7 PMID:7761475

  8. Modeling of Electromagnetic Phenomenon in Fractional Dimensional Space

    NASA Astrophysics Data System (ADS)

    Zubair, Muhammad; Ang, L. K.

    Fractional dimensional space has emerged as an extremely useful concept in many areas of physics, including electromagnetic (EM) theory. The development made in the area of fractional calculus has made it possible to study the most important physical phenomenon in a generalized D-dimensional fractional space. It is worthwhile to mention that many natural objects, such as clouds, snowflakes, rough surfaces, cracks, turbulence in fluids, are aptly described by dimensions of fractional order. Therefore, EM wave propagation in such fractal media is best characterized by considering an effective space of non-integer (fractional) dimensions. Here we present the recent developments in the study of differential Maxwell equations in a D-dimensional fractional space, where D is a non-integer value. Same examples will be used in order to show the transition to the traditional non-fractional conditions or settings.

  9. Role of psychiatry in the phenomenon of cults.

    PubMed

    Levine, S V

    1979-11-01

    Religious cults and particularly their attraction for young people are receiving increased attention. There is currently considerable controversy about the role of governmental bodies in understanding and regulating cults and their effect on members. Regardless of their effect on the members of the cult or movement, particularly new members who are often adolescents, membership in a cult produces severe familial tensions. The cult members often develop opinions and modes of behaviour so diametrically different from their families of origin that psychiatrists are often consulted with the view to understand, treat and correct what is seen as behavioural aberration by the families. The phenomenon of religious cults does not seem to be of a passing nature and it is therefore imperative that psychiatrists have a comprehensive and clear a knowledge of the concepts and activities of cults, their seeming effects on young people and their families, and some of the reactions they have caused in society.

  10. Evolution as a self-organized critical phenomenon

    SciTech Connect

    Sneppen, K.; Bak, P. |; Flyvbjerg, H. |; Jensen, M.H.

    1995-05-23

    We present a simple mathematical model of biological macroevolution. The model describes an ecology of adapting, interacting species. The environment of any given species is affected by other evolving species; hence, it is not constant in time. The ecology as a whole evolves to a {open_quotes}self-organized critical{close_quotes} state where periods of stasis alternate with avalanches of casually connected evolutionary changes. This characteristic behavior of natural history, known as {open_quotes}punctuated equilibrium,{close_quotes} thus finds a theoretical explanation as a self-organized critical phenomenon. The evolutionary behavior of single species is intermittent. Also, large bursts of apparently simultaneous evolutionary activity require no external cause. Extinctions of all sizes, including mass extinctions, may be a simple consequence of ecosystem dynamics. Our results are compared with data from the fossil record. 35 refs., 7 figs.

  11. Theory and Calculation of the Phosphorescence Phenomenon.

    PubMed

    Baryshnikov, Gleb; Minaev, Boris; Ågren, Hans

    2017-05-10

    Phosphorescence is a phenomenon of delayed luminescence that corresponds to the radiative decay of the molecular triplet state. As a general property of molecules, phosphorescence represents a cornerstone problem of chemical physics due to the spin prohibition of the underlying triplet-singlet emission and because its analysis embraces a deep knowledge of electronic molecular structure. Phosphorescence is the simplest physical process which provides an example of spin-forbidden transformation with a characteristic spin selectivity and magnetic field dependence, being the model also for more complicated chemical reactions and for spin catalysis applications. The bridging of the spin prohibition in phosphorescence is commonly analyzed by perturbation theory, which considers the intensity borrowing from spin-allowed electronic transitions. In this review, we highlight the basic theoretical principles and computational aspects for the estimation of various phosphorescence parameters, like intensity, radiative rate constant, lifetime, polarization, zero-field splitting, and spin sublevel population. Qualitative aspects of the phosphorescence phenomenon are discussed in terms of concepts like structure-activity relationships, donor-acceptor interactions, vibronic activity, and the role of spin-orbit coupling under charge-transfer perturbations. We illustrate the theory and principles of computational phosphorescence by highlighting studies of classical examples like molecular nitrogen and oxygen, benzene, naphthalene and their azaderivatives, porphyrins, as well as by reviewing current research on systems like electrophosphorescent transition metal complexes, nucleobases, and amino acids. We furthermore discuss modern studies of phosphorescence that cover topics of applied relevance, like the design of novel photofunctional materials for organic light-emitting diodes (OLEDs), photovoltaic cells, chemical sensors, and bioimaging.

  12. No-reflow phenomenon: maintaining vascular integrity.

    PubMed

    Kloner, Robert A

    2011-01-01

    The no-reflow phenomenon relates to the inability to reperfuse regions of the myocardium after ischemia, despite removal of the large epicardial coronary artery occlusion. The mechanism involves microvascular obstruction. In experimental studies, using markers for flow (thioflavin S, carbon black, microspheres), perfusion defects associated with no-reflow demonstrated ultrastructural evidence of localized endothelial swelling and blebs that appeared to obstruct flow. In humans no-reflow is more complicated due to the microemboli of atherosclerotic debris and thrombi generated by percutaneous coronary intervention. The no-reflow zone expands during the first few hours of reperfusion suggesting an element of reperfusion injury. In animal models, extensive no-reflow was associated with worse infarct expansion. The phenomenon of no-reflow following reperfusion therapy for myocardial infarction in humans has been demonstrated by magnetic resonance imaging, echo contrast agents, thallium, technecium-99m-labeled albumin microspheres, Thrombolysis In Myocardial Infarction (TIMI) scores, and myocardial blush grade. Patients exhibiting no-reflow following reperfusion therapy for myocardial infarction have greater left ventricular dilation and remodeling, more congestive heart failure, shock, and reduced survival. Certain vasodilators (adenosine, nitroprusside, nicorandil, and calcium blockers) are used acutely in the catheterization laboratory and appear to improve no-reflow, but systematic studies on therapy for no-reflow are needed. There is now clinical evidence that no-reflow is a strong predictor of long-term mortality that is independent of and beyond that provided by infarct size. Identifying and treating no-reflow may have important benefits including enhancing delivery of nutrients and cells required for healing and reducing infarct expansion and ventricular remodeling, which ultimately may reduce congestive heart failure and mortality.

  13. Bioelectrographic correlates of the direct vision phenomenon.

    PubMed

    Korotkov, Konstantin G; Bundzen, Pavel V; Bronnikov, Vjacheslav M; Lognikova, Lubov U

    2005-10-01

    A method for training children and adults to perceive visual information without using the eyes has been developed. A study was conducted to investigate the correlation of this perceptual capacity, known as direct vision (DV), with bioelectrographic measurements. Using the technique of dynamic digital gas-discharge visualization (GDV) bioelectrography, seven subjects were tested on three occasions over a 7-month period while they were in the process of reading information from a computer screen and reading printed text; this testing was repeated after an interval of 2 years. In multiple trials it was found that with the perception of information by DV, curves of GDV versus time exhibited specific dynamics, confirming the phenomenon of DV. At least three types of GDV characteristics can be distinguished in this state. This study also identified improvements in the psychosomatic state of children during the 7-month course of training in DV. The phenomenon of DV presents a newly recognized type of human information processing. It is based on a specific type of mental training that is statistically reproducible and has been assimilated by hundreds of children in Russia who are blind or have poor vision. The discovery of DV opens new perspectives in the study of the mechanisms of consciousness. The GDV characteristics that were observed during the perception of information by DV support the hypothesis that DV occurs through signals within the visible range of the electromagnetic spectrum. These results allow the proposal of a hypothesis for the way in which the brain, as well as the human system as a whole, registers information.

  14. The phenomenon of dynamic stall. [vortex shedding phenomenon on oscillating airfoils

    NASA Technical Reports Server (NTRS)

    Mccroskey, W. J.

    1981-01-01

    The general features of dynamic stall on oscillating airfoils are explained in terms of the vortex shedding phenomenon, and the important differences between static stall, light dynamic stall, and deep stall are described. An overview of experimentation and prediction techniques is given.

  15. Flip-flop phenomenon in radiohippuran renal imaging. A sign of obstructive nephropathy

    SciTech Connect

    Shih, W.J.; DeLand, F.H.; Domstad, P.A.

    1986-10-01

    In the dynamic radionuclide brain study, decreased flow in one cerebral hemisphere during the arterial phase followed by relatively increased radioactivity as compared with the contralateral hemisphere has been termed the flip-flop phenomenon, and reflects the development of collateral circulation to the affected side. In I-131 Hippuran renal imaging, relatively decreased activity in one kidney frequently is observed during the initial phase of the study, and is followed by a gradual increase of radioactivity in the late images when compared with the contralateral kidney. To evaluate the significance of this renal flip-flop phenomenon, the studies from 23 patients with these findings were retrospectively compared with the clinical data and findings from other diagnostic studies (CT, ultrasound, intravenous pyelogram, autopsy). Partial obstruction of the renal collecting system was found in all 23 patients. The causes were various malignant tumors in nine patients (colonic carcinoma, three patients; transitional cell carcinoma, three patients; prostatic carcinoma, two patients; seminoma, one patient), ureteropelvic obstruction in three patients, papillary necrosis in one patient, and ureteral fibrosis in one patient. The flip-flop phenomenon reflects asymmetric renal tubular function with decrease (prolonged parenchymal transit time) in the affected kidney as a result of ipsilateral obstruction of the collecting system, while contralateral renal function remains normal or relatively normal. The presence of the flip-flop phenomenon in an I-131 Hippuran renal study suggests the existence of some degree of collecting system obstruction that has persisted long enough to result in renal parenchymal damage.

  16. Lost circulation in geothermal wells: survey and evaluation of industry experience

    SciTech Connect

    Goodman, M.A.

    1981-07-01

    Lost circulation during drilling and completion of geothermal wells can be a severe problem, particularly in naturally fractured and/or vugular formations. Geothermal and petroleum operators, drilling service companies, and independent consultants were interviewed to assess the lost circulation problem in geothermal wells and to determine general practices for preventing lost circulation. This report documents the results and conclusions from the interviews and presents recommendations for needed research. In addition, a survey was also made of the lost circulation literature, of currently available lost circulation materials, and of existing lost circulation test equipment.

  17. Learning Circulant Sensing Kernels

    DTIC Science & Technology

    2014-03-01

    Compressive sensing based high resolution channel estimation for OFDM system. To appear in IEEE Journal of Selected Topics in Signal Processing, Special...and R. D. Nowak. Toeplitz compressed sensing ma- trices with applications to sparse channel estimation . Submitted to IEEE Transactions on Information...various applications. For compressive sens- ing, recent work has used random Toeplitz and circulant sensing matrices and proved their efficiency in theory

  18. Ocean circulation studies

    NASA Technical Reports Server (NTRS)

    Koblinsky, C. J.

    1984-01-01

    Remotely sensed signatures of ocean surface characteristics from active and passive satellite-borne radiometers in conjunction with in situ data were utilized to examine the large scale, low frequency circulation of the world's oceans. Studies of the California Current, the Gulf of California, and the Kuroshio Extension Current in the western North Pacific were reviewed briefly. The importance of satellite oceanographic tools was emphasized.

  19. Posterior Circulation Ischemic Stroke.

    PubMed

    Go, Steven

    2015-01-01

    Approximately 20-25% of all acute strokes occur in the posterior circulation. These strokes can be rather difficult to diagnose because they present in such diverse ways, and can easily be mistaken for more benign entities. A fastidious history, physical exam, high clinical suspicion, and appropriate use of imaging are essential for the emergency physician to properly diagnose and treat these patients. Expert stroke neurologist consultation should be utilized liberally.

  20. Ocean circulation studies

    NASA Technical Reports Server (NTRS)

    Koblinsky, C. J.

    1984-01-01

    Remotely sensed signatures of ocean surface characteristics from active and passive satellite-borne radiometers in conjunction with in situ data were utilized to examine the large scale, low frequency circulation of the world's oceans. Studies of the California Current, the Gulf of California, and the Kuroshio Extension Current in the western North Pacific were reviewed briefly. The importance of satellite oceanographic tools was emphasized.

  1. The fetal circulation.

    PubMed

    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.

  2. [Phenomenon of polyembryony. Genetic heterogeneity of seeds].

    PubMed

    Batygina, T B; Vinogradova, G Iu

    2007-01-01

    Different concepts of polyembryony and genetic heterogeneity of seeds in flower plants have been reviewed. Different types, ways, and forms of plant reproduction appeared in the course of evolution as a consequences of the attached mode of life and autotrophy. This is ascribed to totipotency, "stemminess" of plant cells, and presence of constantly functioning meristems, which determined to a great extent the system of plant safety. There are two ways of formation of a new individual: sexual process --> gamospermy involving meiosis and gamete fusion and asexual process --> agamospermy without meiosis and gamete fusion and two types of reproduction: seed and vegetative. Both processes may take place simultaneously in one seed, as a result of which many embryos of different origins are formed: uniparental and biparental inheritance. Traditionally, this phenomenon is called polyembryony. It comprises embryoidogeny (a new category of vegetative reproduction): formation of somatic embryos (= embryoids) in the flower, seed, and on vegetative organs. Genetic heterogeneity is one of the most important characteristics of seeds, which is based on different phenomena, such as embryogeny, embryoidogeny, and gametophytic and sporophytic apomixes. When describing two types of polyembryony, sporophytic (nucellar, integumental, cleavage) and gametophytic (synergidal, antipodal), a great attention is paid to characterization of initial cells of the sexual and adventive embryos. A new concept of apogamety is developed from new positions (totipotency and "stemminess"), which is based on different genesis of cells of the egg and antipodal systems. Five possible pathways of formation of the adventive embryos have been proposed from cells of the egg apparatus. Specific features of the formation of adventive embryos in the case of gametophytic apomixis, such as androgenesis and semigamy, are discussed. Morphogenesis of the sexual and adventive embryos proceeds in the mother organism and

  3. Epicardial halo phenomenon: a guide for pericardiocentesis?

    PubMed

    Ristić, Arsen D; Wagner, Hans-Joachim; Maksimović, Ružica; Maisch, Bernhard

    2013-05-01

    The epicardial halo delineates the heart shadow in fluoroscopy. To establish whether the sign is applicable to pericardiocentesis guidance, three investigators evaluated its intensity as absent = grade 0, indistinct = 0.5, clear = 1, intensive = 2 in posterior-anterior (PA) and lateral fluoroscopies recorded before pericardiocentesis or cardiac catheterization (Philips Integris-II BH3000). Three populations were studied: (a) 32 patients with pericardial effusion (PE group), 53.1 % males, aged 53.9 ± 13.9 years; (b) 14 patients with perimyocarditis (PM group), 64.3 % males, aged 51.6 ± 14.4 years; and (c) 46 coronary patients (CAD group), no PE, 95.6 % males, aged 67.3 ± 11.8 years. The intensity of the halo phenomenon was highest in patients with PE, lowest in patients with CAD, and intermediate in patients with PM (median sum of grades in PA/lateral view: 4/5 vs. 2/2.5 vs. 3/3, respectively) (p < 0.01). The halo phenomenon correlated well with HR and echocardiographic PE size in both angiographic views. The correlation with body mass index (BMI) and age was significant only in the lateral view and with PE volume only in the PA view. The sensitivity of the halo sign for PE was 84.1 % in PA and 92.0 % in lateral views. In 10/32 PE patients, the evaluation of the sign was repeated after PE drainage, revealing lower grades both in PA and in lateral views (p < 0.01). In conclusion, the epicardial halo sign is highly sensitive for the detection of a PE; it correlates well in at least one angiographic projection with the PE volume, HR, age, BMI, and the PE size in echocardiography and could be therefore applied as a safety guide for pericardiocentesis.

  4. Acoustic characterization of flame blowout phenomenon

    NASA Astrophysics Data System (ADS)

    Nair, Suraj

    Combustor blowout is a very serious concern in modern land-based and aircraft engine combustors. The ability to sense blowout precursors can provide significant payoffs in engine reliability and life. The objective of this work is to characterize the blowout phenomenon and develop a sensing methodology which can detect and assess the proximity of a combustor to blowout by monitoring its acoustic signature, thus providing early warning before the actual blowout of the combustor. The first part of the work examines the blowout phenomenon in a piloted jet burner. As blowout was approached, the flame detached from one side of the burner and showed increased flame tip fluctuations, resulting in an increase in low frequency acoustics. Work was then focused on swirling combustion systems. Close to blowout, localized extinction/re-ignition events were observed, which manifested as bursts in the acoustic signal. These events increased in number and duration as the combustor approached blowout, resulting an increase in low frequency acoustics. A variety of spectral, wavelet and thresholding based approaches were developed to detect precursors to blowout. The third part of the study focused on a bluff body burner. It characterized the underlying flame dynamics near blowout in greater detail and related it to the observed acoustic emissions. Vorticity was found to play a significant role in the flame dynamics. The flame passed through two distinct stages prior to blowout. The first was associated with momentary strain levels that exceed the flame's extinction strain rate, leading to flame "holes". The second was due to large scale alteration of the fluid dynamics in the bluff body wake, leading to violent flapping of the flame front and even larger straining of the flame. This led to low frequency acoustic oscillations, of the order of von Karman vortex shedding. This manifested as an abrupt increase in combustion noise spectra at 40-100 Hz very close to blowout. Finally, work

  5. Library Circulation Systems: An Overview

    ERIC Educational Resources Information Center

    Surace, Cecily J.

    1972-01-01

    The model circulation system outlined is an on-line real time system in which the circulation file is created from the shelf list. The model extends beyond the operational limits of most existing circulation systems and can be considered a reflection of the current state of the art. (36 references) (Author/NH)

  6. Codependency: a concomitant field of interest in research into the phenomenon caring.

    PubMed

    van der Wal, D

    1996-12-01

    The growing popularity of caring is evident throughout the nursing profession. Research into the phenomenon caring, however, necessitates that caring as an ethic be distinguished from pseudo caring actions and experiences. Codependence and codependency are proposed as being of a pseudo-caring nature. Research interest into this field of study needs to be kindled.

  7. A correlated-cluster model and the ridge phenomenon in hadron-hadron collisions

    NASA Astrophysics Data System (ADS)

    Sanchis-Lozano, Miguel-Angel; Sarkisyan-Grinbaum, Edward

    2017-03-01

    A study of the near-side ridge phenomenon in hadron-hadron collisions based on a cluster picture of multiparticle production is presented. The near-side ridge effect is shown to have a natural explanation in this context provided that clusters are produced in a correlated manner in the collision transverse plane.

  8. Priming Intelligent Behavior: An Elusive Phenomenon

    PubMed Central

    Shanks, David R.; Newell, Ben R.; Lee, Eun Hee; Balakrishnan, Divya; Ekelund, Lisa; Cenac, Zarus; Kavvadia, Fragkiski; Moore, Christopher

    2013-01-01

    Can behavior be unconsciously primed via the activation of attitudes, stereotypes, or other concepts? A number of studies have suggested that such priming effects can occur, and a prominent illustration is the claim that individuals' accuracy in answering general knowledge questions can be influenced by activating intelligence-related concepts such as professor or soccer hooligan. In 9 experiments with 475 participants we employed the procedures used in these studies, as well as a number of variants of those procedures, in an attempt to obtain this intelligence priming effect. None of the experiments obtained the effect, although financial incentives did boost performance. A Bayesian analysis reveals considerable evidential support for the null hypothesis. The results conform to the pattern typically obtained in word priming experiments in which priming is very narrow in its generalization and unconscious (subliminal) influences, if they occur at all, are extremely short-lived. We encourage others to explore the circumstances in which this phenomenon might be obtained. PMID:23637732

  9. Raynaud's phenomenon: from molecular pathogenesis to therapy.

    PubMed

    Prete, Marcella; Fatone, Maria Celeste; Favoino, Elvira; Perosa, Federico

    2014-06-01

    Raynaud's phenomenon (RP) is a well defined clinical syndrome characterized by recurrent episodes of digital vasospasm triggered by exposure to physical/chemical or emotional stress. RP has been classified as primary or secondary, depending on whether it occurs as an isolated condition (pRP) or is associated to an underlying disease, mainly a connective tissue disease (CTD-RP). In both cases, it manifests with unique "triple" (pallor, cyanosis and erythema), or "double" color changes. pRP is usually a benign condition, while sRP can evolve and be complicated by acral digital ulcers and gangrene, which may require surgical treatment. The pathogenesis of RP has not yet been entirely clarified, nor is it known whether autoantibodies have a role in RP. Even so, recent advances in our understanding of the pathophysiology have highlighted novel potential therapeutic targets. The aim of this review is to discuss the etiology, epidemiology, risk factors, clinical manifestations, recently disclosed pathogenic mechanisms underlying RP and their correlation with the available therapeutic options, focusing primarily on pRP and CTD-RP.

  10. Antimicrobial resistance: a global multifaceted phenomenon

    PubMed Central

    Prestinaci, Francesca; Pezzotti, Patrizio; Pantosti, Annalisa

    2015-01-01

    Antimicrobial resistance (AMR) is one of the most serious global public health threats in this century. The first World Health Organization (WHO) Global report on surveillance of AMR, published in April 2014, collected for the first time data from national and international surveillance networks, showing the extent of this phenomenon in many parts of the world and also the presence of large gaps in the existing surveillance. In this review, we focus on antibacterial resistance (ABR), which represents at the moment the major problem, both for the high rates of resistance observed in bacteria that cause common infections and for the complexity of the consequences of ABR. We describe the health and economic impact of ABR, the principal risk factors for its emergence and, in particular, we illustrate the highlights of four antibiotic-resistant pathogens of global concern – Staphylococcus aureus, Klebsiella pneumoniae, non-typhoidal Salmonella and Mycobacterium tuberculosis – for whom we report resistance data worldwide. Measures to control the emergence and the spread of ABR are presented. PMID:26343252

  11. [Phenomenon of super-longevity in Yakutia].

    PubMed

    Tatarinova, O V; Kylbanova, E S; Neustroeva, V N; Semenova, A N; Nikitin, Iu P

    2008-01-01

    According to preliminary data of UNESCO the oldest inhabitant of a planet now lives in the Republic Sakha (Yakutia). The article presents some results of the examination of a 117-years long-liver Semennikova (Djakonova) Varvara Konstantinovna. The age of the supercentenarian is certified by the record in the metric book of Yakutsk Spiritual Consistory for the Bulunskiy Spasskiy Church. The standard methods and unified criteria of estimation applied in epidemiological researches and at examination of elderly contingent were used. The health state, lifestyle and quality of life of the supercentenarian have been studied. During physical and instrumental examination of the centenarian the following data have been obtained: asthenic type of the constitution, the lowered index of body weight; the pathology of organism's functional systems (cardiovascular, respiratory, osteomuscular), appeared in senior age. The basic biochemical parameters of the blood are registered within the limits of the norm. The centenarian almost has not suffered from serious diseases. She does not remember long-livers among her relatives. The phenomenon of supercentenarian in Yakutia is the unique example of the extremely high level of adaptation to the extreme climate with prevailing clinically slightly expressed form.

  12. The microwave ultra-fast absorption phenomenon.

    NASA Astrophysics Data System (ADS)

    Chen, Xiaojuan; Ji, Shuchen

    A microwave ultra-fast absorption phenomenon observed with high time resolution on June 29, 1988 is analyzed. This absorption appeared at the atmospheric layer of 4.00 GHz above solar active region 5060 from 07h38m50s to 07h38m58sUT. At atmospheric layers of 2.84 GHz and 1.42 GHz spike emissions appeared. AR5060 was of the configuration of bipolar magnetic field which had strong activity. Hα flares of 3B and 2B were generated from 07h38m to 08h47mUT. X-ray burst of M6.5 also occurred. The authors have calculated the magnetic field of harmonic, S = 2, 3, at three frequencies (4.00 GHz, 2.84 GHz and 1.42 GHz) and analysed the absorption by using the bipolar field model. It is possible that the third harmonic of ECM at frequency of 4.00 GHz, was absorbed when it passed the absorption region.

  13. Doctor shopping: a phenomenon of many themes.

    PubMed

    Sansone, Randy A; Sansone, Lori A

    2012-11-01

    Doctor shopping is defined as seeing multiple treatment providers, either during a single illness episode or to procure prescription medications illicitly. According to the available literature, prevalence rates of doctor shopping vary widely, from 6.3 to 56 percent. However, this variability is partially attributable to research methodology, including the study definition of doctor shopping as well as the patient sample. The reasons for doctor shopping are varied. Some patient explanations for this phenomenon relate to clinician factors, such as inconvenient office hours or locations, long waiting times, personal characteristics or qualities of the provider, and/or insufficient communication time between the patient and clinician. Some patient explanations relate to personal factors and include both illness factors (e.g., symptom persistence, lack of understanding or nonacceptance of the diagnosis or treatment) as well as psychological factors (e.g., somatization, prescription drug-seeking). Importantly, not all doctor shopping is driven by suspect motivations. Being aware of these various patient justifications for doctor shopping is important in understanding and managing these challenging patients in the clinical setting, whether they emerge in psychiatric or primary care environments.

  14. Anesthesia cutoff phenomenon: Interfacial hydrogen bonding

    SciTech Connect

    Chiou, J.S.; Ma, S.M.; Kamaya, H.; Ueda, I. )

    1990-05-04

    Anesthesia cutoff refers to the phenomenon of loss of anesthetic potency in a homologous series of alkanes and their derivatives when their sizes become too large. In this study, hydrogen bonding of 1-alkanol series (ethanol to eicosanol) to dipalmitoyl-L-alpha-phosphatidylcholine (DPPC) was studied by Fourier transform infrared spectroscopy (FTIR) in DPPC-D2O-in-CCl4 reversed micelles. The alkanols formed hydrogen bonds with the phosphate moiety of DPPC and released the DPPC-bound deuterated water, evidenced by increases in the bound O-H stretching signal of the alkanol-DPPC complex and also in the free O-D stretching band of unbound D2O. These effects increased according to the elongation of the carbon chain of 1-alkanols from ethanol (C2) to 1-decanol (C10), but suddenly almost disappeared at 1-tetradecanol (C14). Anesthetic potencies of these alkanols, estimated by the activity of brine shrimps, were linearly related to hydrogen bond-breaking activities below C10 and agreed with the FTIR data in the cutoff at C10.

  15. Lung tissue mechanics as an emergent phenomenon.

    PubMed

    Suki, Béla; Bates, Jason H T

    2011-04-01

    The mechanical properties of lung parenchymal tissue are both elastic and dissipative, as well as being highly nonlinear. These properties cannot be fully understood, however, in terms of the individual constituents of the tissue. Rather, the mechanical behavior of lung tissue emerges as a macroscopic phenomenon from the interactions of its microscopic components in a way that is neither intuitive nor easily understood. In this review, we first consider the quasi-static mechanical behavior of lung tissue and discuss computational models that show how smooth nonlinear stress-strain behavior can arise through a percolation-like process in which the sequential recruitment of collagen fibers with increasing strain causes them to progressively take over the load-bearing role from elastin. We also show how the concept of percolation can be used to link the pathologic progression of parenchymal disease at the micro scale to physiological symptoms at the macro scale. We then examine the dynamic mechanical behavior of lung tissue, which invokes the notion of tissue resistance. Although usually modeled phenomenologically in terms of collections of springs and dashpots, lung tissue viscoelasticity again can be seen to reflect various types of complex dynamic interactions at the molecular level. Finally, we discuss the inevitability of why lung tissue mechanics need to be complex.

  16. Capillaroscopic pattern in paraneoplastic Raynaud's phenomenon.

    PubMed

    Lambova, S; Müller-Ladner, U

    2013-06-01

    The capillaroscopic pattern in paraneoplastic Raynaud's phenomenon (RP) has not been investigated systematically and is not well-defined. Here, we present three case reports of patients with paraneoplastic rheumatic conditions, manifested with severe secondary RP with emphasis upon capillaroscopic findings. The first patient is a 58-year-old male with known psoriasis and psoriatic arthritis, severe RP and scleroderma-like syndrome, resulting in a paraneoplastic syndrome in the context of a lung cancer. At capillaroscopic examination classic "scleroderma" pattern, an "early" type was found. The second patient is a 48-year-old woman with an abrupt onset of paraneoplastic dermatomyositis, severe RP, and a lung cancer. The capillaroscopic examination revealed frequent dilated and giant capillaries, hemorrhages and severe microvascular disarrangement-the so-called "scleroderma-like" pattern typical of the idiopathic forms of the disease. The third patient is a 56-year-old woman with paraneoplastic dermatomyositis, secondary RP, and thyroid cancer. The capillaroscopic examination showed dilated and giant capillaries, elongated capillaries, decreased mean capillary density with avascular areas, severe disarrangement, single hemorrhages, and clear evidence of neoangiogenesis. These capillaroscopic features characteristic of the "scleroderma-like" pattern are indistinguishable from those in idiopathic dermatomyositis like in the second case. Taken together, the cases illustrate the problem that capillaroscopic patterns in paraneoplastic RP in the context of scleroderma-like syndrome and dermatomyositis appear to be indistinguishable from the microvascular changes in the respective idiopathic rheumatic diseases.

  17. General circulation of the ocean

    SciTech Connect

    Abarbanel, H.D.I.; Young, W.R.

    1986-01-01

    This book is an analysis of the geophysics of ocean circulation and its interaction with the atmosphere. It reviews the new concepts and models which have emerged in the last five years, as well as classical theories and observations. The contributions cover topics such as: the observational basis for large-scale circulation, including surface and deep circulation and subtropical gyres; thermocline theories; inverse methods for ocean circulation; baroclinic theories of the wind-driven circulation; and single layer models. This volume sets the current research literature in context, and suggests promising avenues for future study.

  18. A suspicious reason for Raynaud's phenomenon: Intrauterine device.

    PubMed

    Diken, Adem I; Yalçınkaya, Adnan; Aksoy, Eray; Yılmaz, Seyhan; Çağlı, Kerim

    2015-06-01

    Primary Raynaud's phenomenon may be insistent in patients under medical therapy, and intrauterine devices may be an unnoticed reason in these patients. Fluctuations in female sex hormone status were reported to be associated with the emergence of primary Raynaud's phenomenon symptoms. The use of intrauterine devices was not reported to be associated with Raynaud's phenomenon previously. Intrauterine device may stimulate vascular hyperactivity regarding hormonal or unknown mechanisms that result in Raynaud's phenomenon. We present a postmenopausal patient who complained of primary Raynaud's phenomenon symptoms and had recovery after the removal of her copper intrauterine device.

  19. Proof phenomenon as a function of the phenomenology of proving.

    PubMed

    Hipólito, Inês

    2015-12-01

    Kurt Gödel wrote (1964, p. 272), after he had read Husserl, that the notion of objectivity raises a question: "the question of the objective existence of the objects of mathematical intuition (which, incidentally, is an exact replica of the question of the objective existence of the outer world)". This "exact replica" brings to mind the close analogy Husserl saw between our intuition of essences in Wesensschau and of physical objects in perception. What is it like to experience a mathematical proving process? What is the ontological status of a mathematical proof? Can computer assisted provers output a proof? Taking a naturalized world account, I will assess the relationship between mathematics, the physical world and consciousness by introducing a significant conceptual distinction between proving and proof. I will propose that proving is a phenomenological conscious experience. This experience involves a combination of what Kurt Gödel called intuition, and what Husserl called intentionality. In contrast, proof is a function of that process - the mathematical phenomenon - that objectively self-presents a property in the world, and that results from a spatiotemporal unity being subject to the exact laws of nature. In this essay, I apply phenomenology to mathematical proving as a performance of consciousness, that is, a lived experience expressed and formalized in language, in which there is the possibility of formulating intersubjectively shareable meanings.

  20. Is there an obstetric July phenomenon?

    PubMed

    Myles, Thomas D

    2003-11-01

    To estimate whether variations in intrapartum management and complications exist with regard to the time of delivery within the academic year. The delivery records of 7814 patients were separated by both term half year and quarter. Statistical comparisons were made using chi2 tests of association (P < .05) with respect to the academic time of the year and perineal trauma (third- or fourth-degree tear), episiotomy usage, cesarean delivery, postpartum hemorrhage, chorioamnionitis, shoulder dystocia, neonatal intensive care unit admission, 1- or 5-minute Apgar scores less than 7, and low umbilical cord pH. There were 4082 deliveries in the first half and 3732 in the second half of the year from April 1996 through March 1999. The first half-year overall cesarean rate was higher (15.8% versus 14.3%, P < .03). Primary cesarean rates were similar. No other differences were found by term half year. More perineal trauma was noted in the fourth quarter (first 3.3%, second 4.5%, third 3.7%, fourth 5.5%, P < .037). Episiotomy usage was higher in both the first and fourth quarters (13.0%, 11.3%, 10.6%, and 14.8%, P < .002). More cases of chorioamnionitis occurred in the fourth quarter (first 3.4%, second 3.1%, third 2.6%, fourth 4.0%, P < .038, third versus fourth quarter). Chorioamnionitis occurred more frequently in July (July 5.0% versus August-June 3.1%, P < .005). There were no other clinically significant differences. Neonatal outcomes were not affected by academic time of year. Although small differences in outcome exist with respect to the academic time of the year, the timing of these differences indicates that there is not a "July phenomenon" in obstetrics at our institution.

  1. Animal Rights as a Mainstream Phenomenon

    PubMed Central

    Rollin, Bernard E.

    2011-01-01

    Simple Summary The twentieth century has witnessed a bewildering array of ethical revolutions, from civil rights to environmentalism to feminism. Often ignored is the rise of massive societal concern across the world regarding animal treatment. Regulation of animal research exists in virtually all western countries, and reform of “factory farming” is regnant in Europe and rapidly emerging in the United States. Opponents of concern for animals often dismiss the phenomenon as rooted in emotion and extremist lack of appreciation of how unrestricted animal use has improved human life. Such a view totally ignores the rational ethical basis for elevating legal protection for animals, as explained in this essay. Abstract Businesses and professions must stay in accord with social ethics, or risk losing their autonomy. A major social ethical issue that has emerged in the past four decades is the treatment of animals in various areas of human use. Society's moral concern has outgrown the traditional ethic of animal cruelty that began in biblical times and is encoded in the laws of all civilized societies. There are five major reasons for this new social concern, most importantly, the replacement of husbandry-based agriculture with industrial agriculture. This loss of husbandry to industry has threatened the traditional fair contract between humans and animals, and resulted in significant amounts of animal suffering arising on four different fronts. Because such suffering is not occasioned by cruelty, a new ethic for animals was required to express social concerns. Since ethics proceed from preexisting ethics rather than ex nihilo, society has looked to its ethic for humans, appropriately modified, to find moral categories applicable to animals. This concept of legally encoded rights for animals has emerged as a plausible vehicle for reform. PMID:26486217

  2. The Trump phenomenon: An explanation from sociophysics

    NASA Astrophysics Data System (ADS)

    Galam, Serge

    2017-04-01

    The Trump phenomenon is argued to depart from current populist rise in Europe. According to a model of opinion dynamics from sociophysics the machinery of Trump’s amazing success obeys well-defined counter-intuitive rules. Therefore, his success was in principle predictable from the start. The model uses local majority rule arguments and obeys a threshold dynamics. The associated tipping points are found to depend on the leading collective beliefs, cognitive biases and prejudices of the social group which undertakes the public debate. And here comes the open sesame of the Trump campaign, which develops along two successive steps. During a first moment, Trump’s statement produces a majority of voters against him. But at the same time, according to the model the shocking character of the statement modifies the prejudice balance. In case the prejudice is present even being frozen among voters, the tipping point is lowered at Trump’s benefit. Nevertheless, although the tipping point has been lowered by the activation of frozen prejudices it is instrumental to preserve enough support from openly prejudiced people to be above the threshold. Then, as infuriated voters launch intense debate, occurrence of ties will drive progressively hostile people to shift their voting intention without needing to endorse the statement which has infuriated them. The ongoing debate does drive towards a majority for Trump. The possible Trump victory at November Presidential election is discussed. In particular, the model shows that to eventually win the Presidential election, Trump must not modify his past shocking attitude but to appeal to a different spectrum of frozen prejudices, which are common to both Democrats and Republicans.

  3. Weight-based discrimination: an ubiquitary phenomenon?

    PubMed

    Sikorski, C; Spahlholz, J; Hartlev, M; Riedel-Heller, S G

    2016-02-01

    Despite strong indications of a high prevalence of weight-related stigmatization in individuals with obesity, limited attention has been given to the role of weight discrimination in examining the stigma obesity. Studies, up to date, rely on a limited basis of data sets and additional studies are needed to confirm the findings of previous studies. In particular, data for Europe are lacking, and are needed in light of a recent ruling of the European Court of Justice that addressed weight-based discrimination. The data were derived from a large representative telephone survey in Germany (n=3003). The dependent variable, weight-based discrimination, was assessed with a one-item question. The lifetime prevalence of weight discrimination across different sociodemographic variables was determined. Logistic regression models were used to assess the association of independent and dependent variables. A sub-group analysis was conducted analyzing all participants with a body mass index ⩾25 kg m(-)(2). The overall prevalence of weight-based discrimination was 7.3%. Large differences, however, were observed regarding weight status. In normal weight and overweight participants the prevalence was 5.6%, but this number doubled in participants with obesity class I (10.2%), and quadrupled in participants with obesity class II (18.7%) and underweight (19.7%). In participants with obesity class III, every third participant reported accounts of weight-based discrimination (38%). In regression models, after adjustment, the associations of weight status and female gender (odds ratio: 2.59, P<0.001) remained highly significant. Discrimination seems to be an ubiquitary phenomenon at least for some groups that are at special risk, such as heavier individuals and women. Our findings therefore emphasize the need for research and intervention on weight discrimination among adults with obesity, including anti-discrimination legislation.

  4. Electron string phenomenon: physics and use

    NASA Astrophysics Data System (ADS)

    Donets, Evgeny D.

    2004-01-01

    Electron string phenomenon arises as a result of phase transition of a state of multiply reflected electron beam to this new discovered state of one component electron plasma and can be easily observed in the reflex mode of EBIS operation. The transition goes via a strong instability, which causes considerable electron energy spread, which in its turn suppresses the instability. Electron string state is a stationary state of hot pure electron plasma, which is heated by injected electron beam and cooled because of electron loses. Electron string is quiet in broad regions of experimental parameters, so that it is used for confinement and ionization of positive ions by electron impact to highly charge states similar to electron beams in EBIS. Application of electron strings instead of electron beams for ion production allows to save about 99% of electric power of electron beam and simultaneously to improve reliability of an ion source considerably. The JINR EBIS `Krion-2' in the string mode of operation is used for production of N7+, Ar16+ and Fe24+ ion beams and their acceleration to relativistic energies on the facility of the JINR super conducting one turn injection synchrotron `Nuklotron'. The tubular electron string possibly can exist and it is under study now theoretically and experiments are prepared now. Estimations show that a Tubular Electron String Ion Source (TESIS) could have up to three orders of magnitude higher ion output then a Linear one (LESIS). In frames of nuclear astrophysics electron strings can be used for research of fusion nuclear reactions at low energies in conditions when both beam and target nuclei do not carry orbital electrons. The project NARITA — Nuclear Astrophysics Researches in an Ion Trap Apparatus is proposed. Polarization effects also can be studied.

  5. The lens circulation.

    PubMed

    Mathias, Richard T; Kistler, Joerg; Donaldson, Paul

    2007-03-01

    The lens is the largest organ in the body that lacks a vasculature. The reason is simple: blood vessels scatter and absorb light while the physiological role of the lens is to be transparent so it can assist the cornea in focusing light on the retina. We hypothesize this lack of blood supply has led the lens to evolve an internal circulation of ions that is coupled to fluid movement, thus creating an internal micro-circulatory system, which makes up for the lack of vasculature. This review covers the membrane transport systems that are believed to generate and direct this internal circulatory system.

  6. World Ocean Circulation Experiment

    NASA Technical Reports Server (NTRS)

    Clarke, R. Allyn

    1992-01-01

    The oceans are an equal partner with the atmosphere in the global climate system. The World Ocean Circulation Experiment is presently being implemented to improve ocean models that are useful for climate prediction both by encouraging more model development but more importantly by providing quality data sets that can be used to force or to validate such models. WOCE is the first oceanographic experiment that plans to generate and to use multiparameter global ocean data sets. In order for WOCE to succeed, oceanographers must establish and learn to use more effective methods of assembling, quality controlling, manipulating and distributing oceanographic data.

  7. Walker circulation in a transient climate

    NASA Astrophysics Data System (ADS)

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

    2016-04-01

    response (temperature change by the time of CO2 doubling), which in turn might be related to a decreased ocean heat uptake. This uncertainty across the models we attribute to the multitude of factors controlling ocean and atmosphere heat exchange, both at global and regional scales, as well as to the present capabilities of GCMs in simulating this exchange. References: England, M. H., McGregor, S., Spence, P., Meehl, G. A., Timmermann, A., Cai, W., Gupta, A. S., McPhaden, M. J., Purich, A., and Santoso, A., 2014. Recent intensification of wind-driven circulation in the Pacific and the ongoing warming hiatus. Nature Climate Change 4 (3): 222-227. Ma, J., and Xie, S. P., 2013. Regional Patterns of Sea Surface Temperature Change: A Source of Uncertainty in Future Projections of Precipitation and Atmospheric Circulation*. Journal of Climate, 26 (8): 2482-2501

  8. Time-Dependent Rate Phenomenon in Viruses

    PubMed Central

    Aiewsakun, Pakorn

    2016-01-01

    ABSTRACT Among the most fundamental questions in viral evolutionary biology are how fast viruses evolve and how evolutionary rates differ among viruses and fluctuate through time. Traditionally, viruses are loosely classed into two groups: slow-evolving DNA viruses and fast-evolving RNA viruses. As viral evolutionary rate estimates become more available, it appears that the rates are negatively correlated with the measurement timescales and that the boundary between the rates of DNA and RNA viruses might not be as clear as previously thought. In this study, we collected 396 viral evolutionary rate estimates across almost all viral genome types and replication strategies, and we examined their rate dynamics. We showed that the time-dependent rate phenomenon exists across multiple levels of viral taxonomy, from the Baltimore classification viral groups to genera. We also showed that, by taking the rate decay dynamics into account, a clear division between the rates of DNA and RNA viruses as well as reverse-transcribing viruses could be recovered. Surprisingly, despite large differences in their biology, our analyses suggested that the rate decay speed is independent of viral types and thus might be useful for better estimation of the evolutionary time scale of any virus. To illustrate this, we used our model to reestimate the evolutionary timescales of extant lentiviruses, which were previously suggested to be very young by standard phylogenetic analyses. Our analyses suggested that these viruses are millions of years old, in agreement with paleovirological evidence, and therefore, for the first time, reconciled molecular analyses of ancient and extant viruses. IMPORTANCE This work provides direct evidence that viral evolutionary rate estimates decay with their measurement timescales and that the rate decay speeds do not differ significantly among viruses despite the vast differences in their molecular features. After adjustment for the rate decay dynamics, the

  9. Radiology of liver circulation

    SciTech Connect

    Hermine, C.L.

    1985-01-01

    This book proposes that careful evaluation of the arterioportogram is the cornerstone in assessing portal flow obstruction, being the most consistent of all observations including liver histology, portal venous pressure, size and number of portosystemic collaterals, and wedged hepatic venous pressure. Very brief chapters cover normal hepatic circulation and angiographic methods. Contrast volumes and flow rates for celiac, hepatic, and superior mesenteric injection are given, with the timing for venous phase radiographs. In the main body of the text, portal obstruction is divided very simply into presinusoidal (all proximal causes) and postsinusoidal (all distal causes, including Budd-Chiari). Changes are discussed regarding the splenic artery and spleen; hepatic artery and its branches; portal flow rate and direction; and arterioportal shunting and portosystemic collateral circulation in minimal, moderate, severe, and very severe portal obstruction and in recognizable entities such as prehepatic portal and hepatic venous obstructions. The major emphasis in this section is the recognition and understanding of flow changes by which level and severity of obstruction are assessed (not simply the anatomy of portosystemic collateral venous flow). Excellent final chapters discuss the question of portal hypertension without obstruction, and the contribution of arterioportography to the treatment of portal hypertension, again with an emphasis on hemodynamics before and after shunt surgery. There is a fascinating final chapter on segmental intrahepatic obstruction without portal hypertension that explains much of the unusual contrast enhancement sometimes seen in CT scanning of hepatic mass lesions.

  10. North Atlantic Circulation

    NASA Astrophysics Data System (ADS)

    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)).

  11. Circulation of Stars

    NASA Astrophysics Data System (ADS)

    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.

  12. Intravenous Air: The Partially Invisible Phenomenon.

    PubMed

    Varga, Christopher; Luria, Isaac; Gravenstein, Nikolaus

    2016-11-01

    of the resident dissolved gas in room temperature crystalloid, and 4°C packed red blood cells and plasma solutions comes out of solution on warming to body temperature. A nontrivial fraction of this outgassing is also expected to occur within the body circulation based on the results of this study. This can be substantially prevented by prewarming.

  13. Efficient quantum circuits for dense circulant and circulant like operators

    PubMed Central

    Zhou, S. S.

    2017-01-01

    Circulant matrices are an important family of operators, which have a wide range of applications in science and engineering-related fields. They are, in general, non-sparse and non-unitary. In this paper, we present efficient quantum circuits to implement circulant operators using fewer resources and with lower complexity than existing methods. Moreover, our quantum circuits can be readily extended to the implementation of Toeplitz, Hankel and block circulant matrices. Efficient quantum algorithms to implement the inverses and products of circulant operators are also provided, and an example application in solving the equation of motion for cyclic systems is discussed. PMID:28572988

  14. Efficient quantum circuits for dense circulant and circulant like operators

    NASA Astrophysics Data System (ADS)

    Zhou, S. S.; Wang, J. B.

    2017-05-01

    Circulant matrices are an important family of operators, which have a wide range of applications in science and engineering-related fields. They are, in general, non-sparse and non-unitary. In this paper, we present efficient quantum circuits to implement circulant operators using fewer resources and with lower complexity than existing methods. Moreover, our quantum circuits can be readily extended to the implementation of Toeplitz, Hankel and block circulant matrices. Efficient quantum algorithms to implement the inverses and products of circulant operators are also provided, and an example application in solving the equation of motion for cyclic systems is discussed.

  15. Circulating Biomarkers in Bladder Cancer

    PubMed Central

    Nandagopal, Lakshminarayanan; Sonpavde, Guru

    2016-01-01

    Bladder cancer is a molecularly heterogeneous disease characterized by multiple unmet needs in the realm of diagnosis, clinical staging, monitoring and therapy. There is an urgent need to develop precision medicine for advanced urothelial carcinoma. Given the difficulty of serial analyses of metastatic tumor tissue to identify resistance and new therapeutic targets, development of non-invasive monitoring using circulating molecular biomarkers is critically important. Although the development of circulating biomarkers for the management of bladder cancer is in its infancy and may currently suffer from lower sensitivity of detection, they have inherent advantages owing to non-invasiveness. Additionally, circulating molecular alterations may capture tumor heterogeneity without the sampling bias of tissue biopsy. This review describes the accumulating data to support further development of circulating biomarkers including circulating tumor cells, cell-free circulating tumor (ct)-DNA, RNA, micro-RNA and proteomics to improve the management of bladder cancer. PMID:28035318

  16. "Sundowning" as a biological phenomenon: current understandings and future directions: an update.

    PubMed

    Gnanasekaran, Gowrishankar

    2016-06-01

    The clinical phenomenon of early evening disruptive behavior also called "Sundowning" in elderly patients has been largely reported in the medical literature without a consistent diagnosis and criteria to define this phenomenon. The current understandings of sundowning are incomplete and current treatment strategies have relied heavily on use of antipsychotic medications, despite side effects and limited evidence to justify their use. A comprehensive understanding of the biogenesis of this phenomenon and mechanistic changes from oxidative pathways may provide novel information on completing the sundowning puzzle. Future studies could examine the utility of natural factors in reviving neuronal energy loss and altering the oxidative pathways might be safe and additional options in development of treatment models for this behavioral disorder.

  17. Recent achievements in the management of Raynaud's phenomenon.

    PubMed

    Baumhäkel, Magnus; Böhm, Michael

    2010-04-15

    Raynaud's phenomenon is a clinical disorder with episodic digital ischemic vasospasm triggered by cold- or emotional-stress. It was first mentioned by Maurice Raynaud in 1862 describing "a local asphyxia of the extremities" and was further divided into primary Raynaud's disease and secondary Raynaud's phenomenon, which is often related to connective tissue diseases, but also physical or chemical strain. Though pathophysiology of Raynaud's phenomenon is still poorly understood, systemic and local vascular effects are most likely to be involved in primary Raynaud's disease. In secondary Raynaud's phenomenon additional abnormalities in vascular structure and function may play the major role. Thus, medical treatment of Raynaud's phenomenon remains unsatisfactory, due to limited understanding of pathophysiological mechanisms. This review addresses current evidence for medical treatment of primary and secondary Raynaud's phenomenon with regard to pathophysiological mechanisms as well as future perspectives.

  18. Recent achievements in the management of Raynaud’s phenomenon

    PubMed Central

    Baumhäkel, Magnus; Böhm, Michael

    2010-01-01

    Raynaud’s phenomenon is a clinical disorder with episodic digital ischemic vasospasm triggered by cold- or emotional-stress. It was first mentioned by Maurice Raynaud in 1862 describing “a local asphyxia of the extremities” and was further divided into primary Raynaud’s disease and secondary Raynaud’s phenomenon, which is often related to connective tissue diseases, but also physical or chemical strain. Though pathophysiology of Raynaud’s phenomenon is still poorly understood, systemic and local vascular effects are most likely to be involved in primary Raynaud’s disease. In secondary Raynaud’s phenomenon additional abnormalities in vascular structure and function may play the major role. Thus, medical treatment of Raynaud’s phenomenon remains unsatisfactory, due to limited understanding of pathophysiological mechanisms. This review addresses current evidence for medical treatment of primary and secondary Raynaud’s phenomenon with regard to pathophysiological mechanisms as well as future perspectives. PMID:20407628

  19. Raynaud's phenomenon of the nipple associated with labetalol use.

    PubMed

    McGuinness, Naomi; Cording, Vicky

    2013-02-01

    Raynaud's phenomenon of the nipple is an unusual cause of severe nipple pain. Precipitants for Raynaud's phenomenon of the nipple are known to be cold temperatures, caffeine, and emotional stress. Nipple pain is quoted as the most common cause of cessation of breastfeeding. It is important that lactation consultants and other health care professionals are aware of Raynaud's phenomenon of the nipple and the treatment options available. This is a case of a 37-year-old woman, Gravida 2, Para 1, who was first seen in the antenatal clinic at 34 weeks gestation. A diagnosis of Raynaud's phenomenon of the nipple was made after she began taking labetalol for pregnancy-induced hypertension. The phenomenon had occurred in both of her previous pregnancies on commencing labetalol and resolved postnatally on cessation of the drug. We aim to raise awareness of both the condition itself and the potential role of labetalol in the development of Raynaud's phenomenon of the nipple.

  20. Global ocean circulation by altimetry

    NASA Technical Reports Server (NTRS)

    Wunsch, Carl; Haidvogel, D.

    1991-01-01

    The overall objectives of this project are to determine the general circulation of the oceans and many of its climate and biochemical consequences through the optimum use of altimetry data from TOPEX/POSEIDON and related missions. Emphasis is on the global-scale circulation, as opposed to the regional scale, but some more local studies will be carried out. Because of funding limitations, the primary initial focus will be on the time-dependent global-scale circulation rather than the mean; eventually, the mean circulation must be dealt with as well.

  1. Lost circulation technology development status

    SciTech Connect

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

    1992-01-01

    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.

  2. Lost Circulation Technology Development Status

    SciTech Connect

    Glowka, David A.; Schafer, Diane M.; Loeppke, Glen E.; Scott, Douglas D.; Wernig, Marcus D.; Wright, Elton K.

    1992-03-24

    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 U.S. 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.

  3. Separation of Circulating Tokens

    NASA Astrophysics Data System (ADS)

    Ghosh Dastidar, Kajari; Herman, Ted

    Self-stabilizing distributed control is often modeled by token abstractions. For a cyber-physical system, tokens may represent physical objects whose movement is controlled. The problem studied in this paper is to ensure that a synchronous system with m circulating tokens has at least d distance between tokens. This problem is first considered in a ring where d is given whilst m and the ring size n are unknown. The protocol solving this problem can be uniform, with all processes running the same program, or it can be non-uniform, with some processes acting only as token relays. The protocol for this first problem is simple, and can be expressed with Petri net formalism. A second problem is to maximize d when m is given, and n is unknown. For the second problem, the paper presents a non-uniform protocol with a single corrective process.

  4. Ocean General Circulation Models

    SciTech Connect

    Yoon, Jin-Ho; Ma, Po-Lun

    2012-09-30

    1. Definition of Subject The purpose of this text is to provide an introduction to aspects of oceanic general circulation models (OGCMs), an important component of Climate System or Earth System Model (ESM). The role of the ocean in ESMs is described in Chapter XX (EDITOR: PLEASE FIND THE COUPLED CLIMATE or EARTH SYSTEM MODELING CHAPTERS). The emerging need for understanding the Earth’s climate system and especially projecting its future evolution has encouraged scientists to explore the dynamical, physical, and biogeochemical processes in the ocean. Understanding the role of these processes in the climate system is an interesting and challenging scientific subject. For example, a research question how much extra heat or CO2 generated by anthropogenic activities can be stored in the deep ocean is not only scientifically interesting but also important in projecting future climate of the earth. Thus, OGCMs have been developed and applied to investigate the various oceanic processes and their role in the climate system.

  5. Greenland Meltwater and Arctic Circulation Regimes

    NASA Astrophysics Data System (ADS)

    Dukhovskoy, D. S.; Proshutinsky, A. Y.; Timmermans, M. L.; Myers, P. G.; Platov, G.

    2015-12-01

    Between 1948 and 1996, wind-driven components of ice drift and surface ocean currents experienced a well-pronounced decadal variability alternating between anticyclonic and cyclonic circulation regimes. During cyclonic regimes, low sea level atmospheric pressure dominated over the Arctic Ocean driving sea ice and the upper ocean clockwise; the Arctic atmosphere was relatively warm and humid and freshwater flux from the Arctic Ocean toward the sub-Arctic seas was intensified. During anticylonic circulation regimes, high sea level pressure dominated over the Arctic driving sea ice and ocean counter-clockwise; the atmosphere was cold and dry and the freshwater flux from the Arctic to the sub-Arctic seas was reduced. Since 1997, however, the Arctic system has been dominated by an anticyclonic circulation regime with a set of environmental parameters that are atypical for these regimes. Of essential importance is to discern the causes and consequences of the apparent break-down in the natural decadal variability of the Arctic climate system, and specifically: Why has the well-pronounced decadal variability observed in the 20th century been replaced by relatively weak interannual changes under anticyclonic circulation regime conditions in the 21st century? We discuss a hypothesis explaining the causes and mechanisms regulating the intensity and duration of Arctic circulation regimes, and speculate how changes in freshwater fluxes from Greenland impact environmental conditions and interrupt their decadal variability. In order to test this hypothesis, numerical experiments with several FAMOS (Forum for Arctic Modeling & Observational Synthesis) ice-ocean coupled models have been conducted. In these experiments, Greenland melt freshwater is tracked by passive tracers being constantly released along the Greenland coast. Propagation pathways and time scales of Greenland meltwater within the sub-Arctic seas are discussed.

  6. SRB frustrum 'smiley' cracking phenomenon study

    NASA Technical Reports Server (NTRS)

    Cruse, Thomas A.

    1993-01-01

    The thermal protection system installed on the SRB frustrums incurs the formation of debonds between the MSA-2 TPS material and the substrate. The debonds can lead to surface penetrating cracks, called 'smileys' near sealed fasteners and other surface discontinuities. The study concluded that the 'smileys' were caused as the result of stress risers caused by excess fastener sealant (PR-1422) and weakly bonded surfaces. Once the debond occurs, 'smileys' form when the debond area is sufficiently large. The loading for the debond and 'smiley' formation is seen to be depressurization at the vacuum conditions near the end of powered boost. The porous nature of the MSA-2 material covered by a vapor barrier paint provides internal pressure loading of the MSA-2 material. Recommendations for eliminating the problem include elimination of excess PR-1422 sealant and improved attention to bonding surface preparation.

  7. Circulating tumor cells

    PubMed Central

    Raimondi, Cristina; Nicolazzo, Chiara; Gradilone, Angela; Giannini, Giuseppe; De Falco, Elena; Chimenti, Isotta; Varriale, Elisa; Hauch, Siegfried; Plappert, Linda; Cortesi, Enrico; Gazzaniga, Paola

    2014-01-01

    The hypothesis of the “liquid biopsy” using circulating tumor cells (CTCs) emerged as a minimally invasive alternative to traditional tissue biopsy to determine cancer therapy. Discordance for biomarkers expression between primary tumor tissue and circulating tumor cells (CTCs) has been widely reported, thus rendering the biological characterization of CTCs an attractive tool for biomarkers assessment and treatment selection. Studies performed in metastatic colorectal cancer (mCRC) patients using CellSearch, the only FDA-cleared test for CTCs assessment, demonstrated a much lower yield of CTCs in this tumor type compared with breast and prostate cancer, both at baseline and during the course of treatment. Thus, although attractive, the possibility to use CTCs as therapy-related biomarker for colorectal cancer patients is still limited by a number of technical issues mainly due to the low sensitivity of the CellSearch method. In the present study we found a significant discordance between CellSearch and AdnaTest in the detection of CTCs from mCRC patients. We then investigated KRAS pathway activating mutations in CTCs and determined the degree of heterogeneity for KRAS oncogenic mutations between CTCs and tumor tissues. Whether KRAS gene amplification may represent an alternative pathway responsible for KRAS activation was further explored. KRAS gene amplification emerged as a functionally equivalent and mutually exclusive mechanism of KRAS pathway activation in CTCs, possibly related to transcriptional activation. The serial assessment of CTCs may represent an early biomarker of treatment response, able to overcome the intrinsic limit of current molecular biomarkers represented by intratumor heterogeneity. PMID:24521660

  8. PULMONARY CIRCULATION AT EXERCISE

    PubMed Central

    NAEIJE, R; CHESLER, N

    2012-01-01

    The pulmonary circulation is a high flow and low pressure circuit, with an average resistance of 1 mmHg.min.L−1 in young adults, increasing to 2.5 mmHg.min.L−1 over 4–6 decades of life. Pulmonary vascular mechanics at exercise are best described by distensible models. Exercise does not appear to affect the time constant of the pulmonary circulation or the longitudinal distribution of resistances. Very high flows are associated with high capillary pressures, up to a 20–25 mmHg threshold associated with interstitial lung edema and altered ventilation/perfusion relationships. Pulmonary artery pressures of 40–50 mmHg, which can be achieved at maximal exercise, may correspond to the extreme of tolerable right ventricular afterload. Distension of capillaries that decrease resistance may be of adaptative value during exercise, but this is limited by hypoxemia from altered diffusion/perfusion relationships. Exercise in hypoxia is associated with higher pulmonary vascular pressures and lower maximal cardiac output, with increased likelihood of right ventricular function limitation and altered gas exchange by interstitial lung edema. Pharmacological interventions aimed at the reduction of pulmonary vascular tone have little effect on pulmonary vascular pressure-flow relationships in normoxia, but may decrease resistance in hypoxia, unloading the right ventricle and thereby improving exercise capacity. Exercise in patients with pulmonary hypertension is associated with sharp increases in pulmonary artery pressure and a right ventricular limitation of aerobic capacity. Exercise stress testing to determine multipoint pulmonary vascular pressures-flow relationships may uncover early stage pulmonary vascular disease. PMID:23105961

  9. Atmospheric Circulation of Exoplanets

    NASA Astrophysics Data System (ADS)

    Showman, A. P.; Cho, J. Y.-K.; Menou, K.

    2010-12-01

    We survey the basic principles of atmospheric dynamics relevant to explaining existing and future observations of exoplanets, both gas giant and terrestrial. Given the paucity of data on exoplanet atmospheres, our approach is to emphasize fundamental principles and insights gained from solar system studies that are likely to be generalizable to exoplanets. We begin by presenting the hierarchy of basic equations used in atmospheric dynamics, including the Navier-Stokes, primitive, shallow-water, and two-dimensional nondivergent models. We then survey key concepts in atmospheric dynamics, including the importance of planetary rotation, the concept of balance, and simple scaling arguments to show how turbulent interactions generally produce large-scale east-west banding on rotating planets. We next turn to issues specific to giant planets, including their expected interior and atmospheric thermal structures, the implications for their wind patterns, and mechanisms to pump their east-west jets. Hot Jupiter atmospheric dynamics are given particular attention, as these close-in planets have been the subject of most of the concrete developments in the study of exoplanetary atmospheres. We then turn to the basic elements of circulation on terrestrial planets as inferred from solar system studies, including Hadley cells, jet streams, processes that govern the large-scale horizontal temperature contrasts, and climate, and we discuss how these insights may apply to terrestrial exoplanets. Although exoplanets surely possess a greater diversity of circulation regimes than seen on the planets in our solar system, our guiding philosophy is that the multidecade study of solar system planets reviewed here provides a foundation upon which our understanding of more exotic exoplanetary meteorology must build.

  10. Does Hydrothermal Circulation Matter?

    NASA Astrophysics Data System (ADS)

    Stein, C. A.; Stein, S.; von Herzen, R. P.; Fisher, A. T.

    2006-05-01

    Determining Earth's energy budget and the sources and mechanisms for heat transfer within it depends largely on assumptions of the heat loss from the formation and cooling of oceanic lithosphere, which covers about 60% of Earth's surface. Recently Hofmeister and Criss (2005) have suggested that the total global heat flow is about 30 TW, about 25% less than previously estimated by Pollack et al. (1993). The main difference between the two estimates is whether the effects of heat transfer by hydrothermal circulation are included. Thermal models describe the evolution of the lithosphere by the conductive cooling of hot material as it moves away from spreading centers. The frequently used half-space (boundary layer) and "plate" models generally successfully represent heat flow, depth, and geoid values with age, and depth-dependent properties such as flexural thickness, maximum depth of intraplate earthquakes, and lithospheric thickness. However, such models overpredict the measured heat flow from ridge crest to about 65 Myr crust. This difference is generally assumed to reflect water flow in the crust transporting heat, as shown by the spectacular hot springs at midocean ridges. If so, the observed heat flow is lower than the model's predictions, which assume that all heat is transferred by conduction. Because hydrothermal heat transport is hard to quantify, heat flow is about 50% larger than directly measured. This estimate is consistent with observations of hydrothermal circulation which indicate that the discrepancy is largely a result of the water fluxing along the oceanic basement and upwelling at isolated basement highs and outcrops. Detailed studies at such areas often show high heat flow near these outcrops and low heat flow in the surrounding areas. Hence isolated measurements are biased towards lower values and underpredict the total heat flow.

  11. Pulmonary circulation at exercise.

    PubMed

    Naeije, Robert; Chesler, N

    2012-01-01

    The pulmonary circulation is a high-flow and low-pressure circuit, with an average resistance of 1 mmHg/min/L in young adults, increasing to 2.5 mmHg/min/L over four to six decades of life. Pulmonary vascular mechanics at exercise are best described by distensible models. Exercise does not appear to affect the time constant of the pulmonary circulation or the longitudinal distribution of resistances. Very high flows are associated with high capillary pressures, up to a 20 to 25 mmHg threshold associated with interstitial lung edema and altered ventilation/perfusion relationships. Pulmonary artery pressures of 40 to 50 mmHg, which can be achieved at maximal exercise, may correspond to the extreme of tolerable right ventricular afterload. Distension of capillaries that decrease resistance may be of adaptative value during exercise, but this is limited by hypoxemia from altered diffusion/perfusion relationships. Exercise in hypoxia is associated with higher pulmonary vascular pressures and lower maximal cardiac output, with increased likelihood of right ventricular function limitation and altered gas exchange by interstitial lung edema. Pharmacological interventions aimed at the reduction of pulmonary vascular tone have little effect on pulmonary vascular pressure-flow relationships in normoxia, but may decrease resistance in hypoxia, unloading the right ventricle and thereby improving exercise capacity. Exercise in patients with pulmonary hypertension is associated with sharp increases in pulmonary artery pressure and a right ventricular limitation of aerobic capacity. Exercise stress testing to determine multipoint pulmonary vascular pressures-flow relationships may uncover early stage pulmonary vascular disease.

  12. Gilsonite leads fight against lost circulation

    SciTech Connect

    Smith, D.K.; Grant, H. )

    1989-04-01

    A solid hydrocarbon called Gilsonite is widely and effectively used to prevent or cure loss of slurry circulation while cementing oil and gas wells. The low specific gravity (1.05) and sealing characteristics of this material give it the qualities that make it effective against loss of slurry to permeable zones, natural and induced fractures, and caverns. Since Gilsonite was first used for these purposes in 19576, over 200,000 wells have been cemented with Gilsonite slurries. More than one-half billion sacks of the product have been used to mix lost circulation-preventing slurries to bridge thief zones that were accepting cement slurries and preventing achievement of the desired full sheath of cement around the casing.

  13. Current detection technologies for circulating tumor cells.

    PubMed

    Shen, Zheyu; Wu, Aiguo; Chen, Xiaoyuan

    2017-04-10

    Circulating tumor cells (CTCs) are cancer cells that circulate in the blood stream after being naturally shed from original or metastatic tumors, and can lead to a new fatal metastasis. CTCs have become a hotspot research field during the last decade. Detection of CTCs, as a liquid biopsy of tumors, can be used for early diagnosis of cancers, earlier evaluation of cancer recurrence and chemotherapeutic efficacy, and choice of individual sensitive anti-cancer drugs. Therefore, CTC detection is a crucial tool to fight against cancer. Herein, we classify the currently reported CTC detection technologies, introduce some representative samples for each technology, conclude the advantages and limitations, and give a future perspective including the challenges and opportunities of CTC detection.

  14. Climate modelling: Northern Hemisphere circulation.

    PubMed

    Gillett, Nathan P

    2005-09-22

    Air pressure at sea level during winter has decreased over the Arctic and increased in the Northern Hemisphere subtropics in recent decades, a change that has been associated with 50% of the Eurasian winter warming observed over the past 30 years, with 60% of the rainfall increase in Scotland and with 60% of the rainfall decrease in Spain. This trend is inconsistent with the simulated response to greenhouse-gas and sulphate-aerosol changes, but it has been proposed that other climate influences--such as ozone depletion--could account for the discrepancy. Here I compare observed Northern Hemisphere sea-level pressure trends with those simulated in response to all the major human and natural climate influences in nine state-of-the-art coupled climate models over the past 50 years. I find that these models all underestimate the circulation trend. This inconsistency suggests that we cannot yet simulate changes in this important property of the climate system or accurately predict regional climate changes.

  15. Vacuum surface flashover: A high-pressure phenomenon

    SciTech Connect

    Gray, E.W.

    1985-07-01

    Desorbed gases from insulator surfaces may be much more important in flashover initiation than properties of the dielectric surface. Ambient neutral densities, immediately above the insulator surface, in the initial stages of flashover have been calculated to lie in the range from 2 x 10/sup 17//cm/sup 3/ to 2 x 10/sup 21//cm/sup 3/ with a mean of about 1 x 10/sup 19//cm/sup 3/, whether flashover occurred on surfaces in air at atmospheric pressure or in vacuum as low as 10/sup -6/ Torr. The evidence presented indicates that, for dc and microsecond pulse voltages, surface flashover is a local, relatively high-pressure phenomenon. Comparison of field strengths of surface flashover for various insulating materials perpendicular to the electrodes, operating pressures, and voltage waveforms appears to indicate that flashover values range well within an order of magnitude (approx.18--80kV/cm). A filamentary nature of the flashover discharge is shown and is consistent with gas breakdown phenomena. Ionization wave front velocities are examined and these compare favorably with those obtained from gaseous breakdown studies.

  16. Design Construction and Operation of a Supercritical Carbon Dioxide (sCO2) Loop for Investigation of Dry Cooling and Natural Circulation Potential for Use in Advanced Small Modular Reactors Utilizing sCO2 Power Conversion Cycles.

    SciTech Connect

    Middleton, Bobby D.; Rodriguez, Salvador B.; Carlson, Matthew David

    2015-11-01

    This report outlines the work completed for a Laboratory Directed Research and Development project at Sandia National Laboratories from October 2012 through September 2015. An experimental supercritical carbon dioxide (sCO 2 ) loop was designed, built, and o perated. The experimental work demonstrated that sCO 2 can be uti lized as the working fluid in an air - cooled, natural circulation configuration to transfer heat from a source to the ultimate heat sink, which is the surrounding ambient environment in most ca ses. The loop was also operated in an induction - heated, water - cooled configuration that allows for measurements of physical parameters that are difficult to isolate in the air - cooled configuration. Analysis included the development of two computational flu id dynamics models. Future work is anticipated to answer questions that were not covered in this project.

  17. Miniature Gas-Circulating Machine

    NASA Technical Reports Server (NTRS)

    Swift, Walter L.; Valenzuela, Javier A.; Sixsmith, Herbert; Nutt, William E.

    1993-01-01

    Proposed gas-circulating machine consists essentially of centrifugal pump driven by induction motor. Noncontact bearings suppress wear and contamination. Used to circulate helium (or possibly hydrogen or another gas) in regeneration sorption-compressor refrigeration system aboard spacecraft. Also proves useful in terrestrial applications in which long life, reliability, and low contamination essential.

  18. STUDIES ON THE MECHANISM OF THE SHWARTZMAN PHENOMENON

    PubMed Central

    Stetson, Chandler A.; Good, Robert A.

    1951-01-01

    The inhibition of the Shwartzman phenomenon by nitrogen mustard and benzene has been confirmed and investigated further. This inhibition can be correlated with the leucopenia induced by these agents. Evidence is presented indicating that polymorphonuclear leucocytes play an essential role in the preparation of the skin for the Shwartzman phenomenon. PMID:14803631

  19. The Grey Nomad Phenomenon: Changing the Script of Aging

    ERIC Educational Resources Information Center

    Onyx, Jenny; Leonard, Rosemary

    2007-01-01

    This article explores a relatively new and little understood phenomenon, that of the Australian Grey Nomads. Every year increasing numbers of older Australians take to the road. This article explores the phenomenon both empirically and theoretically. A grounded approach is used by which the experience is explored from an ethnographic account…

  20. Raynaud's phenomenon of the nipples: an elusive diagnosis.

    PubMed

    Morino, Carolyn; Winn, Susan M

    2007-05-01

    Pain and throbbing of the nipples associated with Raynaud's phenomenon often mimics yeast or fungal infections. Breastfeeding mothers with Raynaud's of the nipples are often treated inappropriately for organisms such as Candida Albicans with topical or systemic antifungal agents. This case report describes the eventual diagnosis of Raynaud's phenomenon of the nipples in a breastfeeding mother who was initially treated for yeast.

  1. The "Testing" Phenomenon: Not Gone but Nearly Forgotten.

    ERIC Educational Resources Information Center

    Glover, John A.

    1989-01-01

    Four experiments with 263 undergraduates and 57 seventh-graders examined the "testing phenomenon" in relation to students' memory for brief passages and labels for parts of flowers. The phenomenon, which involves the positive effects of previous testing on final test performance, appears to depend on several complete retrieval events. (TJH)

  2. The Grey Nomad Phenomenon: Changing the Script of Aging

    ERIC Educational Resources Information Center

    Onyx, Jenny; Leonard, Rosemary

    2007-01-01

    This article explores a relatively new and little understood phenomenon, that of the Australian Grey Nomads. Every year increasing numbers of older Australians take to the road. This article explores the phenomenon both empirically and theoretically. A grounded approach is used by which the experience is explored from an ethnographic account…

  3. Severe Raynaud's phenomenon with yohimbine therapy for erectile dysfunction.

    PubMed

    Johnson, Sindhu; Iazzetta, John; Dewar, Catharine

    2003-11-01

    Yohimbine is a selective alpha-2 adrenergic antagonist that has been used in the pharmacologic management of erectile dysfunction (ED). We describe a patient with CREST syndrome (calcinosis, Raynaud's phenomenon, esophageal dysfunction, sclerodactyly, and telangiectasia) who paradoxically experienced worsening of Raynaud's phenomenon when using yohimbine for ED.

  4. Raynaud's phenomenon with oral manifestation in systemic lupus erythematosus.

    PubMed

    da Cunha Bang, F; Lange Wantzin, G; Dahl Christensen, J

    1985-01-01

    A 24-year-old woman with discoid lupus erythematosus developed systemic lupus erythematosus after 6 years. One of the clinical features was Raynaud's phenomenon in the fingers and toes, and furthermore Raynaud's phenomenon appeared in the tongue when exposed to cold and windy weather.

  5. The validity of Raynaud's phenomenon symptoms in HAVS cases.

    PubMed

    Youakim, Sami

    2008-09-01

    Raynaud's phenomenon, a common manifestation of the hand-arm vibration syndrome (HAVS), is typically diagnosed by a subjective history provided by employees. This study evaluates the validity of the subjective history of Raynaud's phenomenon provided by individuals applying for compensation for HAVS. Thirty-six workers with a history of occupational hand-arm vibration exposure who were labelled as having Raynaud's phenomenon were asked to photographically document their finger symptoms before undergoing a detailed clinical assessment. Each individual was provided with a disposable camera and instructions. Returned photographs were reviewed for signs of Raynaud's phenomenon. The reliability of photograph interpretation was tested with three physicians and a non-physician. Inter and intra-rater reliability was very good, Kappa coefficient >0.80. Six individuals (17%) did not return cameras. Thirty individuals provided photographs and underwent a clinical evaluation. The photographs of 13 individuals (43%) did not show Raynaud's phenomenon and for four of these the diagnosis was not supported by careful symptom history. Seventeen individuals (57%) had photographic evidence of Raynaud's phenomenon. A presenting history of Raynaud's phenomenon in workers seeking compensation for HAVS may not be accurate since approximately half the cases are unable to provide objective photographic evidence of Raynaud's phenomenon.

  6. The chemical bond as an emergent phenomenon

    NASA Astrophysics Data System (ADS)

    Golden, Jon C.; Ho, Vinh; Lubchenko, Vassiliy

    2017-05-01

    We first argue that the covalent bond and the various closed-shell interactions can be thought of as symmetry broken versions of one and the same interaction, viz., the multi-center bond. We use specially chosen molecular units to show that the symmetry breaking is controlled by density and electronegativity variation. We show that the bond order changes with bond deformation but in a step-like fashion, regions of near constancy separated by electronic localization transitions. These will often cause displacive transitions as well so that the bond strength, order, and length are established self-consistently. We further argue on the inherent relation of the covalent, closed-shell, and multi-center interactions with ionic and metallic bonding. All of these interactions can be viewed as distinct sectors on a phase diagram with density and electronegativity variation as control variables; the ionic and covalent/secondary sectors are associated with on-site and bond-order charge density wave, respectively, the metallic sector with an electronic fluid. While displaying a contiguity at low densities, the metallic and ionic interactions represent distinct phases separated by discontinuous transitions at sufficiently high densities. Multi-center interactions emerge as a hybrid of the metallic and ionic bond that results from spatial coexistence of delocalized and localized electrons. In the present description, the issue of the stability of a compound is that of the mutual miscibility of electronic fluids with distinct degrees of electron localization, supra-atomic ordering in complex inorganic compounds coming about naturally. The notions of electronic localization advanced hereby suggest a high throughput, automated procedure for screening candidate compounds and structures with regard to stability, without the need for computationally costly geometric optimization.

  7. Design of a Slot Height Distribution for Increased Hover Control Power on a Circulation Control Rotor.

    DTIC Science & Technology

    1980-12-01

    I 0Local density of coanda jet, slugs/ft I 1[ I v I I| "I I ABSTRACT The Circulation Control Rotor Performance Prediction computer program was used...tangentially over the trailing edge. Due to a phenomenon called the Coanda effect, which is a balance between pressure and centrifugal forces in the jet around

  8. Aquatic Organic Matter Fluorescence - from phenomenon to application

    NASA Astrophysics Data System (ADS)

    Reynolds, Darren

    2014-05-01

    The use of fluorescence to quantify and characterise aquatic organic matter in river, ocean, ground water and drinking and waste waters has come along way since its discovery as a phenomenon in the early 20th century. For example, there are over 100 papers published each year in international peer reviewed journals, an order of magnitude increase since a decade ago (see Figure taken from ISI database from 1989 to 2007 for publications in the fields of river water and waste water). Since then it has been extensively used as a research tool since the 1990's by scientists and is currently used for a wide variety of applications within a number of sectors. Universities, organisations and companies that research into aquatic organic matter have either recently readily use appropriate fluorescence based techniques and instrumentation. In industry and government, the technology is being taken up by environmental regulators and water and wastewater companies. This keynote presentation will give an overview of aquatic organic matter fluorescence from its conception as a phenomenon through to its current use in a variety of emerging applications within the sectors concerned with understanding, managing and monitoring the aquatic environment. About the Speaker Darren Reynolds pioneered the use of fluorescence spectroscopy for the analysis of wastewaters in the 1990's. He currently leads a research group within the Centre for Research in Biosciences and sits on the Scientific Advisory Board for the Institute of Bio-Sensing Technology at the University of the West of England, Bristol. He is a multidisciplinary scientist concerned with the development of technology platforms for applications in the fields of environment/agri-food and health. His current research interests include the development of optical technologies and techniques for environmental and biological sensing and bio-prospecting applications. He is currently involved in the development and use of synthetic biology

  9. Correction of the Pulfrich phenomenon by surgery and laser.

    PubMed

    Diaper, Charles J M; Heron, Gordon; MacMillan, Ewen S

    2002-02-01

    We describe 2 patients who presented with asymmetrical media changes and a spontaneous Pulfrich phenomenon. In the first case, the phenomenon was due to cataract formation and an interocular latency difference of 1.49 ms +/-0.07 (SD) was found. After cataract surgery, the symptoms resolved and no interocular latency difference could be measured. In the second case, the phenomenon was caused by posterior capsule opacification and an interocular latency difference of 1.16 +/- 0.08 ms was found. The symptoms were alleviated and no interocular latency difference could be measured after a neodymium:YAG laser capsulotomy was performed. The symptomatology of the Pulfrich phenomenon is often difficult for patients to explain. Clinicians should be aware of the phenomenon with cataract patients.

  10. [Study on whorl swarming growth phenomenon of Proteus mirabilis].

    PubMed

    He, Xianyuan; Liao, Sixiang; Liu, Junkang; Li, Kun; Liu, Yanxia; Yu, Lurong

    2015-02-01

    The present paper is aimed to explore the origins of Proteus mirabilis (PM) whorl swarming growth phenomenon. The whorl swarming growth phenomenon of PM was observed by changed bacterial culture inoculation time, humidity, vaccination practices, cultured flat placement, magnetic field, pH and other factors. Bacterial ring spiral direction of rotation is counterclockwise and the volatile growth process of PM was whorl swarming growth phenomenon. Spiro fluctuation phenomenon was of high frequency in the sealing tanks by cultured anytime inoculation, wherever inoculation technique applied or not, the presence or absence of the magnetic field, and wherever the dish position was. The experimental results showed that the whorl swarming growth phenomenon of PM requires specific pH environment, in which the facts may be relative to its genetic characteristics and the Earths rotation.

  11. Testing Mantle Circulation Models

    NASA Astrophysics Data System (ADS)

    Webb, P.; Davies, D.; Davies, J.

    2008-12-01

    Over the past decade, a new family of mantle convection models have been developed, which are conditioned by recent plate motion history (e.g. Bunge et al., 1997). They are commonly known as 'mantle circulation models' and allow for comparisons between present-day model predictions and ever improving seismic tomography images (e.g. Li et al. 2008). In this work, we present results from systematic investigations into the influence of various model parameters upon final model prediction/tomography correlations, to obtain a better understanding of their relative importance. These include a range of material properties, such as the radial viscosity structure, the Clapeyron slope of mineral phase transitions and compressibility; in addition to other aspects, such as the initial condition for the simulation. For our comparisons, we focus in particular on two large robust mid-mantle seismic anomalies, which others have related to the subduction of the Farallon and Tethys plates (e.g. Romanowicz, 1980). While these features are recovered with some fidelity in most simulations, the match can vary greatly. We find that there is a great deal of information in this mismatch, which includes information on the plate motion history.

  12. Sauna bather's circulation.

    PubMed

    Vuori, I

    1988-01-01

    Cutaneous circulation increases greatly in sauna in order to prevent body heating. Blood pressure tends to fall but this is prevented by increased cardiac output by means of faster heart rate and by decreased blood flow to the visceral organs. Cooling in cold air, shower, water or rolling in snow causes rapid cutaneous vasoconstriction, which leads to elevation of arterial blood pressure and increase of central venous blood volume. The effects of both heat and cold are mediated via the sympathetic nervous system. The circulatory responses to sauna are related to the intensity and duration of the heat exposure. An ordinary sauna bath increases cardiac workload about as much as moderate or vigorous walking. Habituation to sauna decreases the sympathetic stimulation and cardiovascular responses. Sudden cooling, for example diving in cold water, causes a severe transitory volume load and pressure load to the heart and increases the possibility of cardiac arrhythmias. The risk of cardiovascular complications in correctly practiced sauna bathing is very small and it is confined to subjects predisposed to the risk because of manifest or latent cardiovascular abnormalities.

  13. The Lymphatic Circulation in Adaptations to the Fontan Circulation.

    PubMed

    Menon, Sabarinath; Chennapragada, Murthy; Ugaki, Shinya; Sholler, Gary F; Ayer, Julian; Winlaw, David S

    2017-06-01

    Failing Fontan continues to be major problem for patients on the univentricular pathway. Failing Fontan is often complicated by chylothorax, plastic bronchitis and protein loosing enteropathy. The role of lymphatic circulation in Fontan circulation is still being researched. Newer imaging modalities give insight into the role of abnormal dilatation and retrograde flow in lymphatic channels post Fontan. Interventional strategies targeting abnormal lymphatic channels, provides an alternative management strategy for patients with failing Fontan. This review focuses on the role of lymphatic system in adaptations to Fontan circulation.

  14. A Study of Electrical Aspects of Neural Conduction with an Emphasis on the Phenomenon of Pain

    DTIC Science & Technology

    1992-12-01

    extrasensory perception .... Theories that have such all- encompassing scope seem to have appeal; however, in general (as in this particular case), they...phenomenon of pain "* the current level of understanding of the electrical nature of the perception and transmission of pain The material in this thesis...Carterette, E.C., and Friedman, M.P., Handbook of Perception , v.VIB, Academic Press, 1978. Chu, L.S., Acupuncture Manual: A Western Approach, M. Dekker

  15. Multiple Circulating Cytokines Are Coelevated in Chronic Obstructive Pulmonary Disease

    PubMed Central

    Todd, Ian; John, Michelle; Bolton, Charlotte E.; Harrison, Timothy

    2016-01-01

    Inflammatory biomarkers, including cytokines, are associated with COPD, but the association of particular circulating cytokines with systemic pathology remains equivocal. To investigate this, we developed a protein microarray system to detect multiple cytokines in small volumes of serum. Fourteen cytokines were measured in serum from never-smokers, ex-smokers, current smokers, and COPD patients (GOLD stages 1–3). Certain individual circulating cytokines (particularly TNFα and IL-1β) were significantly elevated in concentration in the serum of particular COPD patients (and some current/ex-smokers without COPD) and may serve as markers of particularly significant systemic inflammation. However, numerous circulating cytokines were raised such that their combined, but not individual, elevation was significantly associated with severity of disease, and these may be further indicators of, and contributors to, the systemic inflammatory manifestations of COPD. The coelevation of numerous circulating cytokines in COPD is consistent with the insidious development, chronic nature, and systemic comorbidities of the disease. PMID:27524865

  16. Multiple Circulating Cytokines Are Coelevated in Chronic Obstructive Pulmonary Disease.

    PubMed

    Selvarajah, Senthooran; Todd, Ian; Tighe, Patrick J; John, Michelle; Bolton, Charlotte E; Harrison, Timothy; Fairclough, Lucy C

    2016-01-01

    Inflammatory biomarkers, including cytokines, are associated with COPD, but the association of particular circulating cytokines with systemic pathology remains equivocal. To investigate this, we developed a protein microarray system to detect multiple cytokines in small volumes of serum. Fourteen cytokines were measured in serum from never-smokers, ex-smokers, current smokers, and COPD patients (GOLD stages 1-3). Certain individual circulating cytokines (particularly TNFα and IL-1β) were significantly elevated in concentration in the serum of particular COPD patients (and some current/ex-smokers without COPD) and may serve as markers of particularly significant systemic inflammation. However, numerous circulating cytokines were raised such that their combined, but not individual, elevation was significantly associated with severity of disease, and these may be further indicators of, and contributors to, the systemic inflammatory manifestations of COPD. The coelevation of numerous circulating cytokines in COPD is consistent with the insidious development, chronic nature, and systemic comorbidities of the disease.

  17. When Prostate Cancer Circulates in the Bloodstream

    PubMed Central

    Vlaeminck-Guillem, Virginie

    2015-01-01

    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. PMID:26854164

  18. Zwitterionic Poly(carboxybetaine)-based Cationic Liposomes for Effective Delivery of Small Interfering RNA Therapeutics without Accelerated Blood Clearance Phenomenon

    PubMed Central

    Li, Yan; Liu, Ruiyuan; Shi, Yuanjie; Zhang, Zhenzhong; Zhang, Xin

    2015-01-01

    For efficient delivery of small interfering RNA (siRNA) to the target diseased site in vivo, it is important to design suitable vehicles to control the blood circulation of siRNA. It has been shown that surface modification of cationic liposome/siRNA complexes (lipoplexes) with polyethylene glycol (PEG) could enhance the circulation time of lipoplexes. However, the first injection of PEGylated lipoplexes in vivo induces accelerated blood clearance and enhances hepatic accumulation of the following injected PEGylated lipoplexes, which is known as the accelerated blood clearance (ABC) phenomenon. Herein, we developed zwitterionic poly(carboxybetaine) (PCB) modified lipoplexes for the delivery of siRNA therapeutics, which could avoid protein adsorption and enhance the stability of lipoplexes as that for PEG. Quite different from the PEGylation, the PCBylated lipoplexes could avoid ABC phenomenon, which extended the blood circulation time and enhanced the tumor accumulation of lipoplexes in vivo. After accumulation in tumor site, the PCBylation could promote the cellular uptake and endosomal/lysosomal escape of lipoplexes due to its unique chemical structure and pH-sensitive ability. With excellent tumor accumulation, cellular uptake and endosomal/lysosomal escape abilities, the PCBylated lipoplexes significantly inhibited tumor growth and induced tumor cell apoptosis. PMID:25825598

  19. Zwitterionic poly(carboxybetaine)-based cationic liposomes for effective delivery of small interfering RNA therapeutics without accelerated blood clearance phenomenon.

    PubMed

    Li, Yan; Liu, Ruiyuan; Shi, Yuanjie; Zhang, Zhenzhong; Zhang, Xin

    2015-01-01

    For efficient delivery of small interfering RNA (siRNA) to the target diseased site in vivo, it is important to design suitable vehicles to control the blood circulation of siRNA. It has been shown that surface modification of cationic liposome/siRNA complexes (lipoplexes) with polyethylene glycol (PEG) could enhance the circulation time of lipoplexes. However, the first injection of PEGylated lipoplexes in vivo induces accelerated blood clearance and enhances hepatic accumulation of the following injected PEGylated lipoplexes, which is known as the accelerated blood clearance (ABC) phenomenon. Herein, we developed zwitterionic poly(carboxybetaine) (PCB) modified lipoplexes for the delivery of siRNA therapeutics, which could avoid protein adsorption and enhance the stability of lipoplexes as that for PEG. Quite different from the PEGylation, the PCBylated lipoplexes could avoid ABC phenomenon, which extended the blood circulation time and enhanced the tumor accumulation of lipoplexes in vivo. After accumulation in tumor site, the PCBylation could promote the cellular uptake and endosomal/lysosomal escape of lipoplexes due to its unique chemical structure and pH-sensitive ability. With excellent tumor accumulation, cellular uptake and endosomal/lysosomal escape abilities, the PCBylated lipoplexes significantly inhibited tumor growth and induced tumor cell apoptosis.

  20. Shaping Meridional Circulation in Solar and Stellar Convection Zones

    NASA Astrophysics Data System (ADS)

    Featherstone, N. A.; Miesch, M. S.

    2014-12-01

    Meridional circulations play a crucial role in mediating the angular momentum transport within stellar convection zones and, likely, in determining the nature and timing of their dynamos. The length of the solar cycle, for instance, is thought to depend intimately on the transport of magnetic fields by the meridional circulations in the convection zone. 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 provide insight into those processes responsible for driving and shaping the meridional circulations established within stellar convection zones. These 3-D models have been constructed in such a way as to span the transition between regimes of solar-like differential rotation (fast equator, slow poles) and regimes of so-called ``anti-solar'' differential rotation (slow equator, fast poles). Solar-like states of differential rotation are characterized by multiple cells of meridional circulation in depth at low latitudes, whereas anti-solar states of differential rotation are characterized by a single cell of circulation within each hemisphere. We demonstrate that the transition from single-celled to multi-celled meridional circulation profiles in these two different regimes is directly linked to a change in the nature of the convective Reynolds stress. These results suggest that if convection in the Sun is strongly rotationally-constrained, a multi-cellular meridional circulation profile may well be expected. Transitional regimes do exist, however, and we conclude by examining a simulation wherein convection that is only marginally rotationally constrained can drive both mono-cellular meridional circulation and solar-like differential rotation.

  1. Uhthoff's phenomenon in multiple sclerosis and neuromyelitis optica.

    PubMed

    Park, Kwiyoung; Tanaka, Keiko; Tanaka, Masami

    2014-01-01

    To evaluate and compare the incidence and clinical features of Uhthoff's phenomenon in Japanese patients with neuromyelitis optica (NMO) and those with multiple sclerosis (MS), we asked 135 consecutive patients with MS and an NMO-related disorder (NMOrd) whether they experienced worse neurological symptoms after an increase in body temperature. Responses were obtained from 54 MS and 37 NMOrd patients. Uhthoff's phenomenon was observed in 26 MS (48.1%) and 20 NMOrd patients (54.1%). Motor and sensory symptoms were more frequent than visual symptoms in both diseases. The incidence of Uhthoff's phenomenon was similar in MS and NMOrd.

  2. Lucio's phenomenon: exuberant case report and review of Brazilian cases*

    PubMed Central

    Rocha, Rafael Henrique; Emerich, Paulo Sergio; Diniz, Lucia Martins; de Oliveira, Marcela Bahia Barretto; Cabral, Aline Neves Freitas; do Amaral, Ana Cristina Vervloet

    2016-01-01

    Lucio’s phenomenon is an uncommon reaction characterized by severe necrotizing cutaneous lesions that occurs in patients with Lucio’s leprosy and lepromatous leprosy. It is considered by some authors as a variant of type 2 or 3 reaction. Death can occur because of blood dyscrasia or sepsis. Precipitating factors include infections, drugs and pregnancy. We report a 31-year-old female patient exhibiting both clinical and histopathological features of lepromatous leprosy and Lucio’s phenomenon presenting favorable response to treatment. We complement our report with a literature review of the Brazilian cases of Lucio’s phenomenon published in Portuguese and English. PMID:28300896

  3. Severe Raynaud's phenomenon-A streamlined approach to acute management.

    PubMed

    Lee, Regent; Lomas, Oliver; Handa, Ashok

    2011-01-01

    Raynaud's phenomenon is an exaggerated vasospastic response to cold or emotional stress which not only may cause the patient severe pain but also critical ischaemia and necrosis of the digits. We report the case of a 69-year-old woman who presented with rest pain, impending ulceration and necrosis of finger tips due to an episode of left-sided Raynaud's phenomenon. Intravenous prostacyclin was administered successfully as a bridge to endoscopic thoracic sympathectomy. Vascular surgery units are ideally positioned for the acute management of severe Raynaud's phenomenon to provide continuity of care to patients with profound digital ischaemia and impending tissue loss.

  4. The Page kidney phenomenon secondary to a traumatic fall.

    PubMed

    Babel, Nitin; Sakpal, Sujit Vijay; Chamberlain, Ronald Scott

    2010-02-01

    Page kidney is a rare phenomenon of hyperreninemic hypertension caused by compression of the renal parenchyma. It has been reported in healthy individuals after blunt abdominal or flank trauma, and in patients after invasive nephrological interventions. We present a case of acute on chronic renal failure and Page kidney phenomenon in an elderly male after a traumatic fall, who underwent effective medical management until spontaneous recovery to baseline was observed. A brief discussion on the Page kidney phenomenon is provided with a suggested algorithmic approach towards the management of this process.

  5. Red Blood Cell Membrane as a Biomimetic Nanocoating for Prolonged Circulation Time and Reduced Accelerated Blood Clearance.

    PubMed

    Rao, Lang; Bu, Lin-Lin; Xu, Jun-Hua; Cai, Bo; Yu, Guang-Tao; Yu, Xiaolei; He, Zhaobo; Huang, Qinqin; Li, Andrew; Guo, Shi-Shang; Zhang, Wen-Feng; Liu, Wei; Sun, Zhi-Jun; Wang, Hao; Wang, Tza-Huei; Zhao, Xing-Zhong

    2015-12-01

    For decades, poly(ethylene glycol) (PEG) has been widely incorporated into nanoparticles for evading immune clearance and improving the systematic circulation time. However, recent studies have reported a phenomenon known as "accelerated blood clearance (ABC)" where a second dose of PEGylated nanomaterials is rapidly cleared when given several days after the first dose. Herein, we demonstrate that natural red blood cell (RBC) membrane is a superior alternative to PEG. Biomimetic RBC membrane-coated Fe(3)O(4) nanoparticles (Fe(3)O(4) @RBC NPs) rely on CD47, which is a "don't eat me" marker on the RBC surface, to escape immune clearance through interactions with the signal regulatory protein-alpha (SIRP-α) receptor. Fe(3)O(4) @RBC NPs exhibit extended circulation time and show little change between the first and second doses, with no ABC suffered. In addition, the administration of Fe(3)O(4) @RBC NPs does not elicit immune responses on neither the cellular level (myeloid-derived suppressor cells (MDSCs)) nor the humoral level (immunoglobulin M and G (IgM and IgG)). Finally, the in vivo toxicity of these cell membrane-camouflaged nanoparticles is systematically investigated by blood biochemistry, hematology testing, and histology analysis. These findings are significant advancements toward solving the long-existing clinical challenges of developing biomaterials that are able to resist both immune response and rapid clearance. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. Car surfing: case studies of a growing dangerous phenomenon.

    PubMed

    Clark, Steven; Mangram, Alicia; Dunn, Ernest

    2008-03-01

    Car surfing is a dangerous new pastime for American youth. Car surfing is an activity that is defined as standing (or lying) on a vehicle while it is being driven. This activity frequently results in severe injuries that often require significant surgical intervention. Despite its destructive nature, however, there are many Internet sites that encourage this behavior and view it as amusing. As a result, car surfing is becoming increasingly popular. We conducted a retrospective chart review of all patients injured as a result of car surfing over the last 4 years at our Urban Level II trauma center. Data collected included Injury Severity Score (ISS), Revised Trauma Score (RTS), age, gender, injury pattern, surgical intervention, and length of stay. Eight car surfers were identified. The average age was 17. The average Revised Trauma Score was 6.8 with an average Injury Severity Score of 16.9. Five patients were admitted to the intensive care unit. Four of these five patients needed to be intubated for ventilatory support. Five of the eight patients had significant intracranial injuries. Two patients had epidural hematomas that required evacuation. Two other patients had subdural hematomas that were treated nonoperatively, and one patient had a subarachnoid hemorrhage that was also treated nonoperatively. Four of the eight patients required surgical intervention. There were no deaths in this study. Car surfing leads to severe injuries that can result in significant morbidity. American youth have access to Internet sites that project this activity as an acceptable behavior. Five of our eight patients had a significant intracranial injury. Trauma surgeons need to be more aware of this injury phenomenon.

  7. Palinacousis--evidence to suggest a post-ictal phenomenon.

    PubMed

    Mohamed, Wazim; Ahuja, Niharika; Shah, Aashit

    2012-06-15

    Palinacousis is a paroxysmal auditory illusion in which perseveration of an external auditory stimulus occurs after cessation of the stimulus. The subjects recognize the illusory nature of this experience, which is often a fragment of the last sentence they heard. Palinacousis has been reported in only a few documented cases. It has been described as an aura, a component of complex partial seizures, and a post-ictal event. We put forward evidence demonstrating palinacousis as a post-ictal event. A 68-year-old woman presented with an acute sensory aphasia, and an EEG showed frequent epileptiform discharges from the left temporo-parietal region. MRI showed an enhancing mass in the left inferior parietal lobule that was consistent with a metastasis. A CT scan of the thorax later showed an enhancing mass in the left lung that was determined to be an invasive non-small cell carcinoma. Treatment with levetiracetam resulted in loss of epileptiform activity on EEG and resolution of aphasia, but soon afterward, she started complaining of recurrent auditory illusions in her right ear. These consisted of phrases from the ends of sentences she heard. Continuous EEG monitoring during her auditory symptoms showed intermittent left temporal slowing but no epileptiform discharges or electrographic seizures. An FDG-PET scan with the glucose uptake phase during episodes of auditory illusions revealed hypometabolism of bilateral medial temporal cortices and increased uptake in the metastatic tumor. A systematic review identified 14 cases with palinacousis since 1981. Cases prior to that were excluded due to the lack of sufficient data. We propose that palinacousis is a "negative" phenomenon, at least in some individuals. It occurs with a loss of function of a region of the brain that normally suppresses auditory perseveration. Copyright © 2012 Elsevier B.V. All rights reserved.

  8. Living through the end: The phenomenon of dying at home.

    PubMed

    Solomon, Diane N; Hansen, Lissi

    2015-04-01

    To explore the unique lived experiences of one patient who died at home and her family members, and to interpret how dying at home influenced patterns of bereavement for this patient's family. Benner's (1985) interpretive phenomenological approach was employed to get at the embedded nature of the social phenomenon of dying at home, uncovering what may be taken for granted by participants - in this case, during and after the patient's home hospice course. The participants were a 78-year-old female diagnosed with amyotrophic lateral sclerosis six months prior to death, her husband, and three of her four children. In line with the patient's wish to die at home, she voluntarily forewent food and drink when she no longer wished to watch her body deteriorate and felt that her life had run its course. She informed her family of this plan, and all were supportive. For data collection, separate single in-depth interviews were conducted with the deceased three months prior to death, and after death with three of her four children and her spouse of 60 years. For data analysis, the interview transcripts were coded for paradigm cases, exemplars, and themes. The paradigm case, "The Meaning of Being at Home," revealed that for study participants, remaining home with hospice provided a richly familiar, quiet, and safe environment for being together over time and focusing on relationships. Exemplars included "Driving Her Own Course" and "Not Being a Burden." Salient themes encompassed patient and family characteristics, support, emotions, the value of time, and aspects of the healthcare team. End-of-life care providers need to hold a patient-centered, family-focused view to facilitate patient and family wishes to remain home to die. Investigation into family relationships, from the perspectives of both patient and family members, longitudinally, may enrich understanding and ability and help patients to die at home.

  9. A proposal to describe a phenomenon of expanding language

    NASA Astrophysics Data System (ADS)

    Swietorzecka, Kordula

    Changes of knowledge, convictions or beliefs are subjects of interest in frame of so called epistemic logic. There are various proposed descriptions of a process (or its results) in which so a called agent may invent certain changes in a set of sentences that he had already chosen as a point of his knowledge, convictions or beliefs (and this is also considered in case of many agents). In the presented paper we are interested in the changeability of an agent's language which is by its own independent from already mentioned changes. Modern epistemic formalizations assume that the agent uses a fixed (and so we could say: static) language in which he expresses his various opinions which may change. Our interest is to simulate a situation when a language is extended by adding to it new expressions which were not known by the agent so he couldn't even consider them as subjects of his opinions. Actually such a phenomenon happens both in natural and scientific languages. Let us mention a fact of expanding languages in process of learning or in result of getting of new data about some described domain. We propose a simple idealization of extending sentential language used by one agent. Actually the language is treated as a family of so called n-languages which get some epistemic interpretation. Proposed semantics enables us to distinguish between two different types of changes - these which occur because of changing agent's convictions about logical values of some n-sentences - we describe them using one place operator C to be read it changes that - and changes that consist in increasing the level of n-language by adding to it new expressions. However the second type of change - symbolized by variable G - may be also considered independently of the first one. The logical frame of our considerations comes from and it was originally used to describe Aristotelian theory of substantial changes. This time we apply the mentioned logic in epistemology.

  10. Salinity Boundary Conditions and the Atlantic Meridional Overturning Circulation in Depth and Quasi-Isopycnic Coordinate Global Ocean Models

    DTIC Science & Technology

    2009-06-30

    2006. Investigating the causes of the response of the thermohaline circulation to past and future climate changes . J. Clim. 19, 1365-1387. Sun, S...Global climatic impacts of a collapse of the Atlantic thermohaline circulation , Clim. Change 54, 251– 267. Willebrand, J., et al., 2001. Circulation ...Rahmstorf, S., 1995. Bifurcations of the Atlantic thermohaline circulation in response to changes in the hydrological cycle. Nature 378, 145-149

  11. LLNL Ocean General Circulation Model

    SciTech Connect

    Wickett, M. E.; Caldeira, K.; Duffy, P.

    2005-12-29

    The LLNL OGCM is a numerical ocean modeling tool for use in studying ocean circulation over a wide range of space and time scales, with primary applications to climate change and carbon cycle science.

  12. Circulating Progenitor Cells and Scleroderma

    PubMed Central

    2010-01-01

    Scleroderma (systemic sclerosis) is a disease of unknown origins that involves tissue ischemia and fibrosis in the skin and internal organs such as the lungs. The tissue ischemia is due to a lack of functional blood vessels and an inability to form new blood vessels. Bone marrow–derived circulating endothelial progenitor cells play a key role in blood vessel repair and neovascularization. Scleroderma patients appear to have defects in the number and function of circulating endothelial progenitor cells. Scleroderma patients also develop fibrotic lesions, possibly as the result of tissue ischemia. Fibroblast-like cells called fibrocytes that differentiate from a different pool of bone marrow–derived circulating progenitor cells seem to be involved in this process. Manipulating the production, function, and differentiation of circulating progenitor cells represents an exciting new possibility for treating scleroderma. PMID:18638425

  13. Inverse Bell's Phenomenon: Rare Ophthalmic Finding Following Ptosis Surgery.

    PubMed

    Shitole, Satish; Jakkal, Tapan; Khaire, Bhasakar

    2015-03-01

    Bell's phenomenon is protective reflex in which the globe is turned upwards and slightly outwards during the eyelid closure to avoid corneal exposure. In Inverse Bell's phenomenon, the eye moves downward instead of upward, this may be seen in the normal population, patients with Bell's palsy or following conjunctival scarring. We hereby present the unusual complication of transient inversion of Bell's phenomenon following extensive levator resection surgery performed for congenital ptosis. A 24-year-old male was undergone ptosis correction surgery. On postoperative day two, ocular examination revealed down rolling of eye ball during eyelid closure. It underwent spontaneous resolution within four weeks without any corneal complication. The patients were given frequent lubricating eye drops during this period and advised frequent follow-up for early diagnosis of corneal complication. Here we highlight an inverse Bell's phenomenon following levator resection surgery, its possible mechanism and risk of corneal complication.

  14. Rumpel-Leede phenomenon presenting as a hypertensive urgency.

    PubMed

    Varela, Daniel; Tran, Dat; Ngamdu, Kyari Sumayin; Trullender, Brett; Mukherjee, Debabrata; Abbas, Aamer

    2016-04-01

    Rumpel-Leede (R-L) phenomenon is the rare event in which the small dermal capillaries of an extremity rupture in response to application of a compressive device to that extremity, such as when inflating a cuff during noninvasive blood pressure monitoring or when applying a tourniquet to draw blood. This capillary rupture results in formation of a petechial rash distal to the compressive device. R-L phenomenon is believed to occur most often in patients with underlying vascular disease, such as diabetes mellitus or thrombocytopenia. R-L phenomenon is most often benign, though it may rarely be associated with pain and discomfort. There is no treatment for this condition apart from treatment of the underlying vascular disease or thrombocytopenia. We report a 57-year-old woman who presented with hypertensive urgency and experienced R-L phenomenon during blood pressure cuff inflation.

  15. Glow phenomenon surrounding the vertical stabilizer and OMS pods

    NASA Technical Reports Server (NTRS)

    1994-01-01

    This 35mm frame, photographed as the Space Shuttle Columbia was orbiting Earth during a 'night' pass, documents the glow phenomenon surrounding the vertical stabilizer and the Orbital Maneuvering System (OMS) pods of the spacecraft.

  16. Glow phenomenon surrounding the vertical stabilizer and OMS pods

    NASA Technical Reports Server (NTRS)

    1994-01-01

    This 35mm frame, photographed as the Space Shuttle Columbia was orbiting Earth during a 'night' pass, documents the glow phenomenon surrounding the vertical stabilizer and the Orbital Maneuvering System (OMS) pods of the spacecraft.

  17. Spontaneous Involution of Congenital Melanocytic Nevus With Halo Phenomenon.

    PubMed

    Lee, Noo Ri; Chung, Hee-Chul; Hong, Hannah; Lee, Jin Wook; Ahn, Sung Ku

    2015-12-01

    Congenital melanocytic nevus (CMN) is a neural crest-derived hamartoma, which appear at or soon after birth. CMN has a dynamic course and may show variable changes over time, including spontaneous involution. Spontaneous involution of CMN is a rare phenomenon and is often reported in association with halo phenomenon or vitiligo. The mechanism of halo phenomenon is yet to be investigated but is suggested to be a destruction of melanocytes by immune responses of cytotoxic T cells or IgM autoantibodies. Here, the authors report an interesting case of spontaneously regressed medium-sized CMN with halo phenomenon and without vitiligo, which provides evidence that cytotoxic T cells account for the halo formation and pigmentary regression of CMN.

  18. Professor Nambu, string theory, and the moonshine phenomenon

    NASA Astrophysics Data System (ADS)

    Eguchi, Tohru

    2016-11-01

    I first recall the last occasion I met the late Professor Yoichiro Nambu, in a hospital in Osaka. I then present a brief introduction to a moonshine phenomenon in string theory that have recently come under investigation.

  19. Symptomatic Epidural Gas-containing Cyst from Intervertebral Vacuum Phenomenon.

    PubMed

    Yun, Sung Min; Suh, Bumn Suk; Park, Jin Su

    2012-12-01

    Vacuum disc phenomenon is a collection of gas in the intervertebral disc space but rarely causes nerve compression. However, some rare type of vacuum phenomenon in the spinal canal may bring about posterior gas displacement within the epidural space. The authors describe two patients with symptomatic epidural gas-containing cyst that seem to be originating from vacuum phenomenon in the intervertebral disc, causing lumbosacral radiculopathy. Radiographic studies demonstrated intervertebral vacuum phenomenon and accumulation of gas in the lumbar epidural space compressing the dural sac and the nerve root. The nerve root in both patients was compressed by gas containing cyst that was surrounded by thin walled capsule separable from the gaseous degenerated disc space. The speculative mechanism of the nerve root compression is discussed. The possibility of gas containing cyst should be considered in case of the nerve root compression in which epidural gas is present.

  20. Benign "setting sun" phenomenon in full-term infants.

    PubMed

    Yoshikawa, Hideto

    2003-06-01

    I report two normally developed infants showing benign" setting sun" phenomenon. A 2(2-12)-year-old boy and a 7-year-old boy, who were born without any complications at full term, developed brief episodes of downward gazing during sucking and crying after birth However, there were no other clinical or laboratory findings, and they developed normally. The phenomenon was not visible until 6 months and 7 months, respectively. The "setting sun" phenomenon usually indicates underlying severe brain damage and can also be seen, although rarely, in healthy full-term infants until 1 to 5 months. However, the benign "setting sun" phenomenon might exist until 6 or 7 months of age in normal infants.

  1. Rumpel-Leede phenomenon presenting as a hypertensive urgency

    PubMed Central

    Tran, Dat; Ngamdu, Kyari Sumayin; Trullender, Brett; Mukherjee, Debabrata; Abbas, Aamer

    2016-01-01

    Rumpel-Leede (R-L) phenomenon is the rare event in which the small dermal capillaries of an extremity rupture in response to application of a compressive device to that extremity, such as when inflating a cuff during noninvasive blood pressure monitoring or when applying a tourniquet to draw blood. This capillary rupture results in formation of a petechial rash distal to the compressive device. R-L phenomenon is believed to occur most often in patients with underlying vascular disease, such as diabetes mellitus or thrombocytopenia. R-L phenomenon is most often benign, though it may rarely be associated with pain and discomfort. There is no treatment for this condition apart from treatment of the underlying vascular disease or thrombocytopenia. We report a 57-year-old woman who presented with hypertensive urgency and experienced R-L phenomenon during blood pressure cuff inflation. PMID:27034570

  2. Prevalence of Raynaud's phenomenon in young Greek males.

    PubMed

    Tzilalis, Vassilios; Panagiotopoulos, Nikolaos; Papatheodorou, George; Rallis, Efstathios; Kassimos, Dimitrios

    2011-01-01

    The aim of this paper is to study the prevalence of Raynaud's phenomenon in young males. Young males were examined prospectively in a district hospital, and laboratory tests were performed on the basis of the clinical history. Young males (3.912), age 18-28 years old, were examined. Raynaud's phenomenon was present in seven men (1,79 per 1.000, 95% CI 0.72-3.68). Three of them had at least one member in their family diagnosed with Raynaud's phenomenon. Three were smokers. All had negative immunological test. Five patients reported having severe attacks and two had only mild ischemic attacks. The treatment was conservative for all patients, two of them necessitated vasodilators. Very low prevalence of Raynaud's phenomenon was observed in this young male group compared with the previous studies.

  3. Post-Traumatic Raynaud's Phenomenon: A Case Report.

    PubMed

    Cheok, Liang Jie; Ooi, Chee Kheong

    2017-06-01

    Raynaud's phenomenon has multiple etiologies, ranging from occupational causes to systemic disease. Most occupational causes of Raynaud's phenomenon usually present with vascular compromise. A 41-year-old Chinese woman presented to the emergency department with progressive pain and bluish discoloration over her right index finger after minor trauma. The clinical examination revealed discoloration over multiple fingertips on both hands. She was diagnosed with Raynaud's phenomenon with possible underlying systemic disease. Additional laboratory workup led to the diagnosis of systemic lupus erythematosus with complex regional pain syndrome. WHY SHOULD AN EMERGENCY PHYSICIAN BE AWARE OF THIS?: It is rare for the emergency physician to diagnose Raynaud's phenomenon in the setting of minor trauma. It is important to diagnose this condition because of its potential complications. Copyright © 2017 Elsevier Inc. All rights reserved.

  4. Post-traumatic Raynaud's phenomenon following volar plate injury.

    PubMed

    Chodakiewitz, Yosef G; Daniels, Alan H; Kamal, Robin N; Weiss, Arnold-Peter C

    2014-04-01

    Post-traumatic Raynaud's phenomenon following non-penetrating or non-repetitive injury is rare. We report a case of Raynaud's phenomenon occurring in a single digit 3 months following volar plate avulsion injury. Daily episodes of painless pallor of the digit occurred for 1 month upon any exposure to cold, resolving with warm water therapy. Symptoms resolved after the initiation of hand therapy, splinting, and range-of- motion exercises.

  5. DOE lost circulation technology development

    SciTech Connect

    Glowka, D.A.; Staller, G.E.; Sattler, A.R.

    1996-09-01

    Lost circulation is a problem common in both the geothermal and the solution mining industries. In both cases, drilling is on a relatively large scale (geothermal holes can be as large as 26 inches). Lost circulation technology development for geothermal drilling has been in progress at Sandia National Laboratories for more than 15 years. The initial work centered on lost circulation materials, but testing and modeling indicated that if the aperture of a loss zone is very large (larger than the drill bit nozzles) it cannot be plugged by simply adding materials to the drilling fluid. Thus, the lost circulation work evolved to include: (1) Development of metering techniques that accurately measure and characterize drilling fluid inflow and outflow for rapid diagnosis of los circulation and/or fluid balance while drilling. (2) Construction of a laboratory facility for testing drillable straddle packers (to improve the plugging efficiency of cementing operations) and the actual testing of components of the straddle packer. (3) Construction of a laboratory facility for the testing of candidate porous fabrics as a part of a program to develop a porous packer that places polyurethane foam into a loss zone. (4) Implementing (with Halliburton and CalEnergy Company), a program to test cementitious lost circulation material as an alternative to Portland cement.

  6. V838 Monocerotis revisited: Space phenomenon imitates art

    NASA Astrophysics Data System (ADS)

    2004-03-01

    V838 Monocerotis revisited: Space phenomenon imitates art hi-res Size hi-res: 558 Kb Credits: NASA, the Hubble Heritage Team (AURA/STScI) and ESA V838 Monocerotis revisited: Space phenomenon imitates art "Starry Night", Vincent van Gogh's famous painting, is renowned for its bold whorls of light sweeping across a raging night sky. Although this image of the heavens came only from the artist's restless imagination, a new picture from the NASA/ESA Hubble Space Telescope bears remarkable similarities to the van Gogh work, complete with never-before-seen spirals of dust swirling across trillions of kilometres of interstellar space. This image, obtained with the Advanced Camera for Surveys on February 8, 2004, is Hubble's latest view of an expanding halo of light around a distant star, named V838 Monocerotis (V838 Mon). The illumination of interstellar dust comes from the red supergiant star at the middle of the image, which gave off a flashbulb-like pulse of light two years ago. V838 Mon is located about 20,000 light-years away from Earth in the direction of the constellation Monoceros, placing the star at the outer edge of our Milky Way galaxy V838 Monocerotis revisited: Space phenomenon imitates art hi-res Size hi-res: 1989 kb Credits: NASA, the Hubble Heritage Team (AURA/STScI) and ESA V838 Monocerotis revisited: Space phenomenon imitates art "Starry Night", Vincent van Gogh's famous painting, is renowned for its bold whorls of light sweeping across a raging night sky. Although this image of the heavens came only from the artist's restless imagination, a new picture from the NASA/ESA Hubble Space Telescope bears remarkable similarities to the van Gogh work, complete with never-before-seen spirals of dust swirling across trillions of kilometres of interstellar space. This image, obtained with the Advanced Camera for Surveys on February 8, 2004, is Hubble's latest view of an expanding halo of light around a distant star, named V838 Monocerotis (V838 Mon). The

  7. Abnormal platelet aggregation in patients with Raynaud's phenomenon.

    PubMed Central

    Biondi, M L; Marasini, B

    1989-01-01

    Platelet aggregation in vitro to several aggregating agents (serotonin (5-HT), adenosine diphosphate, adrenaline and collagen) was studied in 16 patients with primary and secondary Raynaud's phenomenon and compared with that in 13 normal volunteers. Platelets from patients with Raynaud's phenomenon had significantly greater responses to all the 5-HT concentrations tested (p less than 0.001 for 10 microM; p less than 0.01 for 1 microM; p less than 0.05 for 0.1 microM; p less than 0.02 for 0.025 microM) and to low doses of adenosine diphosphate (p less than 0.01 for 1 microM; p less than 0.02 for 0.5 microM) but normal responses to collagen, adrenaline, and high doses of adenosine diphosphate. Patients with secondary Raynaud's phenomenon were significantly more hypersensitive to 0.5 microM adenosine diphosphate than patients with primary Raynaud's phenomenon. In patients with secondary Raynaud's phenomenon there was a significant correlation between the extent of 5-HT aggregation and the duration of the disease. The finding that platelets from patients with Raynaud's phenomenon have enhanced responses to 5-HT and adenosine diphosphate, but normal responses to adrenaline and collagen, is consistent with a role for 5-HT in this disease. PMID:2760232

  8. [Raynaud's phenomenon - first sign of malignancy: case report].

    PubMed

    Sutić, Anamarija; Gračanin, Gudelj; Morović-Vergles, Jadranka

    2014-06-01

    Raynaud's phenomenon is a common phenomenon in the general population. It most commonly occurs in healthy individuals, in whom there is no associated illness or any other cause of Raynaud's phenomenon (primary or idiopathic Raynaud's phenomenon). Secondary Raynaud's phenomenon is common with rheumatic diseases (systemic sclerosis, systemic lupus erythematosus, primary Sjögren's syndrome, mixed connective tissue disease, etc.), occlusive vascular diseases, hematologic disorders, use of vibrating tools and use of some medications, and rarely with malignancy. We report on a patient who presented with a three-week history of painful Raynaud's attacks, which was the reason for seeking assistance of internists in emergency clinic. Upon admission to the hospital and diagnostic work-up, adenocarcinoma of the lung was found. Antinuclear antibodies (ANA), anti-dsDNA antibodies, anticardiolipin IgM and IgG antibodies were present in a lower titer. It is known that rheumatoid factor or ANA characteristic of rheumatic disease are often present in patients with paraneoplastic rheumatic syndromes, which can lead to wrong conclusions about the possible systemic connective tissue diseases and ultimately delay the correct diagnosis. The first appearance of Raynaud's phenomenon as an isolated symptom in people older than 50, with painful signs of ischemia, as in our patient, or the occurrence of asymmetric grasping fingers, especially in men, regardless of the presence of RF, ANA, anti-dsDNA or other autoantibodies, requires broader diagnostic evaluation for malignancy.

  9. Dietary Human Milk Oligosaccharides but Not Prebiotic Oligosaccharides Increase Circulating Natural Killer Cell and Mesenteric Lymph Node Memory T Cell Populations in Noninfected and Rotavirus-Infected Neonatal Piglets.

    PubMed

    Comstock, Sarah S; Li, Min; Wang, Mei; Monaco, Marcia H; Kuhlenschmidt, Theresa B; Kuhlenschmidt, Mark S; Donovan, Sharon M

    2017-06-01

    Background: Human milk oligosaccharides (HMOs) have antimicrobial and immunomodulatory actions. It has previously been reported that these oligosaccharides contribute to the reduced duration of rotavirus-induced diarrhea in pigs.Objective: We measured the effects of HMOs and prebiotic oligosaccharides on immune cell populations from noninfected and rotavirus-infected pigs. We hypothesized that dietary HMOs would modulate systemic and gastrointestinal immunity.Methods: Colostrum-deprived newborn pigs were fed formula, formula with 4 g HMOs/L (2'-fucosyllactose, lacto-N-neotetraose, 6'-sialyllactose, 3'-sialyllactose, and free sialic acid), or formula with 3.6 g short-chain galactooligosaccharides/L and 0.4 g long-chain fructooligosaccharides/L. On day 10, half of the pigs were infected with the porcine rotavirus strain OSU. Peripheral blood mononuclear cell (PBMC), mesenteric lymph node (MLN), and ileal Peyer's patch immune cell populations were assessed with the use of flow cytometry 5 d postinfection. Interferon-γ (IFN-γ)-producing cells were assessed with the use of Enzyme-Linked ImmunoSpot assay.Results: Infection changed immune cell populations with more systemic natural killer (NK) cells, memory effector T cells, and major histocompatibility complex II(+) cells in infected than noninfected pigs (P < 0.06). Regardless of infection status, HMO-fed pigs had nearly twice as many PBMC NK cells, 36% more MLN effector memory T cells, and 5 times more PBMC basophils than formula-fed pigs (P < 0.04). These populations were intermediate in pigs fed prebiotics. PBMCs from HMO-fed noninfected pigs had twice as many IFN-γ-producing cells as did those from formula-fed noninfected pigs (P = 0.017). The PBMCs and MLNs of formula-fed noninfected pigs had 3 times more plasmacytoid dendritic cells (pDCs) than those of HMO-fed noninfected and formula-fed infected pigs (P < 0.04). In the MLNs, the formula-fed noninfected pigs had more macrophages, pDCs, and mature DCs (P < 0

  10. The relationship of maternal characteristics and circulating progesterone concentrations with reproductive outcome in the bottlenose dolphin (Tursiops truncatus) after artificial insemination, with and without ovulation induction, and natural breeding.

    PubMed

    O'Brien, J K; Robeck, T R

    2012-08-01

    Bottlenose dolphins (Tursiops truncatus) undergoing natural breeding and artificial insemination (AI) were examined to characterize serum progesterone concentrations and determine relationships among age, parity, and reproductive outcome. Progesterone profiles of five cycle types (n = 119 total cycles from 54 animals) were characterized as follows: (i) conception and production of a live term calf (conceptive-term, n = 73); (ii) conception and abortion after Day 60 (conceptive-abortion, n = 12); (iii) unknown conception status with prolonged, elevated progesterone and absence of a fetus (conceptive-unknown, n = 14); (iv) conception failure with normal luteal phase progesterone concentrations (non-conceptive, n = 14, AI cycles only); and (v) conception failure with progesterone insufficiency occuring after spontaneous ovulation or owing to premature ovulation induction using GnRH (non-conceptive-PI, n = 6, AI cycles only). By Day 21 post-insemination (PI), progesterone concentrations were similar (P > 0.05) among conceptive-term, conceptive-abortion and conceptive-unknown, and higher (P < 0.05) for conceptive-term than non-conceptive and non-conceptive-PI cycles. Progesterone concentrations of known conceptive cycles peaked by Week 7 PI (P < 0.05) and remained elevated for the remainder of pregnancy (Weeks 8 up to 54, ≥ 5 days pre-partum). During midpregnancy (Days 121-240), conceptive-term cycles had higher (P > 0.05) progesterone concentrations than conceptive-abortion and unknown conception status cycles. Parity was not associated with reproductive outcome based on cycle type (P > 0.05). Age of females in conceptive-unknown (26.5 ± 10.1 yrs) and conceptive-abortion (22.1 ± 9.4 yrs) groups was higher (P < 0.05) than in conceptive-term (15.7 ± 7.2 yrs). The conceptive-unknown cycle type possibly represents undetected early embryonic loss occurring before Day 60 PI. Length of gestation using known conception dates was 376.1 ± 11.0 days and the range of this

  11. Increased caloric intake after a high-fat preload: relation to circulating triglycerides and orexigenic peptides.

    PubMed

    Gaysinskaya, V A; Karatayev, O; Chang, G-Q; Leibowitz, S F

    2007-05-16

    To investigate mechanisms that mediate the greater food intake induced by a fat-rich diet, the present study tested an acute "preload-to-test meal" paradigm in normal-weight rats. In this paradigm, the rats were given a small high-fat (HF) compared to low-fat (LF) preload and, after an intermeal interval, allowed to consume freely on a subsequent test meal. Modified versions of this paradigm were tested to determine the robustness of the greater caloric intake induced by the HF preload while standardizing the test protocol. A HF preload of 10-15 kcals, compared to an equicaloric LF preload, significantly increased food intake by 40-50% in the subsequent test meal. This effect, a 4-6 kcal increase, was observed with HF preloads equal in energy density and palatability to the LF preloads. It was evident with preloads or test meals that were liquid or solid, preloads that were injected, test meals that had variable fat content, and natural intermeal intervals of 60-120 min. This overeating after a HF preload was invariably associated with a 2- to 3-fold increase in circulating levels of triglycerides (TG), with no change in leptin or insulin. It was also accompanied by increased expression of the orexigenic peptides, galanin in the paraventricular nucleus and orexin in the perifornical lateral hypothalamus. Moreover, if given repeatedly over several days, the HF compared to equicaloric LF preload significantly increased 24-h food intake. These results establish a protocol for studying the phenomenon of increased feeding on a HF diet under controlled conditions and suggest possible underlying mechanisms involving circulating lipids and orexigenic peptides.

  12. Laboratory measurements of the generation and evolution of Langmuir circulations

    NASA Astrophysics Data System (ADS)

    Melville, W. Kendall; Shear, Robert; Veron, Fabrice

    1998-06-01

    We present laboratory measurements of the generation and evolution of Langmuir circulations as an instability of a wind-driven surface shear layer. The shear layer, which is generated by an accelerating wind starting from rest above a quiescent water surface, both accelerates and deepens monotonically until the inception of the Langmuir circulations. The Langmuir circulations closely follow the initial growth of the wind waves and rapidly lead to vertical mixing of the horizontal momentum and a deceleration of the surface layer. Prior to the appearance of the Langmuir circulations, the depth of the shear layer scales with (vt)1/2 (v is the kinematic viscosity and t is time), in accordance with molecular rather than turbulent transport. For final wind speeds in the range 3 to 5 m s[minus sign]1, the wavenumber of the most unstable Langmuir circulation normalized by the surface wavenumber, k*lc, is 0.68±0.24, at a reciprocal Langmuir number, La[minus sign]1, of 52±21. The observations are compared with available theoretical results, although none are directly applicable to the conditions of the experiments. The implications of this work for the generation and evolution of Langmuir circulations in the ocean and other natural water bodies are discussed.

  13. Satellite Altimetry, Ocean Circulation, and Data Assimilation

    NASA Technical Reports Server (NTRS)

    Fu, Lee-Lueng

    1999-01-01

    Ocean circulation is a critical factor in determining the Earth's climate. Satellite altimetry has been proven a powerful technique for measuring the height of the sea surface for the study of global ocean circulation dynamics. A major objective of my research is to investigate the utility of altimeter data for ocean circulation studies. The 6 years' data record of TOPEX/POSEIDON have been analyzed to study the spatial and temporal characteristics of large-scale ocean variability. A major result obtained in 1998 is the discovery of large-scale oscillations in sea level with a period of 25 days in the Argentine Basin of the South Atlantic Ocean (see diagram). They exhibit a dipole pattern with counterclockwise rotational propagation around the Zapiola Rise (centered at 45S and 317E), a small seamount in the abyssal plain of the basin. The peak-to-trough amplitude is about 10 cm over a distance of 500-1000 km. The amplitude of these oscillations has large seasonal-to-interannual variations. The period and rotational characteristics of these oscillations are remarkably similar to the observations made by two current meters deployed near the ocean bottom in the region. What TOPEX/POSEIDON has detected apparently are manifestations of the movement of the entire water column (barotropic motion). The resultant transport variation is estimated to be about 50 x 10(exp 6) cubic M/S, which is about 50% of the total water transport in the region. Preliminary calculations suggest that these oscillations are topographically trapped waves. A numerical model of the South Atlantic is used to investigate the nature of and causes for these waves. A very important property of sea surface height is that it is directly related to the surface geostrophic velocity, which is related to deep ocean circulation through the density field. Therefore altimetry observations are not only useful for determining the surface circulation but also for revealing information about the deep ocean. Another

  14. Satellite Altimetry, Ocean Circulation, and Data Assimilation

    NASA Technical Reports Server (NTRS)

    Fu, Lee-Lueng

    1999-01-01

    Ocean circulation is a critical factor in determining the Earth's climate. Satellite altimetry has been proven a powerful technique for measuring the height of the sea surface for the study of global ocean circulation dynamics. A major objective of my research is to investigate the utility of altimeter data for ocean circulation studies. The 6 years' data record of TOPEX/POSEIDON have been analyzed to study the spatial and temporal characteristics of large-scale ocean variability. A major result obtained in 1998 is the discovery of large-scale oscillations in sea level with a period of 25 days in the Argentine Basin of the South Atlantic Ocean (see diagram). They exhibit a dipole pattern with counterclockwise rotational propagation around the Zapiola Rise (centered at 45S and 317E), a small seamount in the abyssal plain of the basin. The peak-to-trough amplitude is about 10 cm over a distance of 500-1000 km. The amplitude of these oscillations has large seasonal-to-interannual variations. The period and rotational characteristics of these oscillations are remarkably similar to the observations made by two current meters deployed near the ocean bottom in the region. What TOPEX/POSEIDON has detected apparently are manifestations of the movement of the entire water column (barotropic motion). The resultant transport variation is estimated to be about 50 x 10(exp 6) cubic M/S, which is about 50% of the total water transport in the region. Preliminary calculations suggest that these oscillations are topographically trapped waves. A numerical model of the South Atlantic is used to investigate the nature of and causes for these waves. A very important property of sea surface height is that it is directly related to the surface geostrophic velocity, which is related to deep ocean circulation through the density field. Therefore altimetry observations are not only useful for determining the surface circulation but also for revealing information about the deep ocean. Another

  15. Differential uptake of grepafloxacin by human circulating blood neutrophils and those exudated into tissues.

    PubMed

    Niwa, M; Hotta, K; Kanamori, Y; Matsuno, H; Kozawa, O; Hirota, M; Uematsu, T

    2001-09-28

    The uptake of the antimicrobial quinolone agent, grepafloxacin, both by human circulating blood neutrophils and by those exudated into tissues, was evaluated in vitro by comparing the intracellular drug concentrations. In circulating blood neutrophils, the uptake of grepafloxacin was rapid and saturable at 37 degrees C. The uptake of grepafloxacin into circulating blood neutrophils was reduced by lowering the environmental temperature or by the presence of metabolic inhibitors, suggesting the involvement of an active transport mechanism. Furthermore, the uptake of grepafloxacin by tissue (salivary) neutrophils was also partially temperature-dependent and was significantly greater than that by circulating blood neutrophils, i.e. exudation of neutrophils into tissue results in a markedly enhanced transport mechanism for grepafloxacin. This phenomenon may be related to the higher defense activity against infection seen in exudated tissue neutrophils.

  16. Application of remote sensing to study nearshore circulation. [and the continental shelf

    NASA Technical Reports Server (NTRS)

    Zeigler, J.; Lobecker, R.; Stauble, D.; Welch, C.; Haas, L.; Fang, C. S.

    1974-01-01

    The research to use remote sensing techniques for studying the continental shelf is reported. The studies reported include: (1) nearshore circulation in the vincinity of a natural tidal inlet; (2) identification of indicators of biological activity; (3) remote navigation system for tracking free drifting buoys; (4) experimental design of an estuaring tidal circulation; and (5) Skylab support work.

  17. Circulating microRNAs in Cardiovascular Diseases.

    PubMed

    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.

  18. Organizational Tonypandy: Lessons from a Quarter Century of the Groupthink Phenomenon.

    PubMed

    Fuller; Aldag

    1998-02-01

    We adopt the role of devil's advocate, arguing that the quarter-century experience with groupthink represents an unfortunate episode in the history of group problem solving research. In view of the facts that there has been remarkably little empirical support for the groupthink phenomenon, that the phenomenon rests on arguable assumptions, that published critiques of groupthink have generally been ignored by groupthink researchers, and that groupthink is presented as fact in journal articles and textbooks, we see continued advocacy of groupthink as a form of organizational Tonypandy, in which knowledgeable individuals fail to speak out against widely accepted but erroneous beliefs. We explore the nature and causes of this Tonypandy and encourage researchers to cast off the artificial determinism and constraints of the groupthink model and instead seek to inform the general group decision making literature. Copyright 1998 Academic Press.

  19. Scaling in non-stationary time series. (II). Teen birth phenomenon

    NASA Astrophysics Data System (ADS)

    Ignaccolo, M.; Allegrini, P.; Grigolini, P.; Hamilton, P.; West, B. J.

    2004-05-01

    This paper is devoted to the problem of statistical mechanics raised by the analysis of an issue of sociological interest: the teen birth phenomenon. It is expected that these data are characterized by correlated fluctuations, reflecting the cooperative properties of the process. However, the assessment of the anomalous scaling generated by these correlations is made difficult, and ambiguous as well, by the non-stationary nature of the data that shows a clear dependence on seasonal periodicity (periodic component) and an average changing slowly in time (slow component) as well. We use the detrending techniques described in the companion paper [The earlier companion paper], to safely remove all the biases and to derive the genuine scaling of the teen birth phenomenon.

  20. Effects of oligomerization phenomenon on dissolved organic matter removal kinetics on novel activated carbons.

    PubMed

    Yan, Liang; Deeter, Valerie; Lalley, Jacob; Medellin, Oscar; Kupferle, Margaret J; Sorial, George A

    2014-08-15

    The overall objective of this research was to determine the effects of oxidative coupling (oligomerization) phenomenon on the adsorption kinetics of dissolved natural organic matter (DOM) on novel tailored activated carbons. A comparison of adsorption kinetics data collected in the presence and absence of phenolic compounds under both oxic (presence of molecular oxygen) and anoxic (absence of molecular oxygen) conditions showed that the adsorption rate of DOM was strongly affected by the oligomerization phenomenon. The diffusion rate of DOM is in inverse proportion to the critical oxidation potential of the phenolic compound. In addition, the roles of carbon physicochemical characteristics and DOM molecular weight distribution were also investigated. Tailored activated carbon impregnated with manganese oxide was found to play an important role in promoting complexation reactions between DOM and phenolic compounds. Meanwhile, Fulvic acid molecules (component of DOM) with molecular weight below 2000 Da appeared to have more potential to get influenced from oligomerization effects.

  1. Analysis of rewarming curves in Raynaud's phenomenon of various aetiologies.

    PubMed

    Salem, K M; Baker, M; Hilliam, R M; Davies, S; Deighton, C; Bainbridge, L C; Manning, G

    2009-10-01

    This study investigated whether a modified Cold Provocation Test could distinguish between 86 normal subjects and 31 patients with Raynaud's phenomenon or 59 with hand arm vibration syndrome (HAVS). Of the HAVS subjects, 56 were seen for medical reports as they were involved in litigation. Their assessments were done in a different location but the same protocol was used. A standardised cold stress was used to reduce the finger temperature to 15 degrees C or less without inducing reflex hyperaemia. This test had acceptable repeatability for subjects without HAVS with an intra-class correlation of 0.7. Baseline temperature, temperature rise in the first 30 seconds and the time taken to rewarm by 5 degrees C were measured. Patients with Raynaud's phenomenon and HAVS had cooler hands than controls. HAVS patients rewarmed most in the first 30 seconds. Patients with Raynaud's phenomenon take longer to rewarm by 5 degrees C than controls or those with HAVS (P<0.001). A baseline difference of >7.5 degrees C between the temperature of the digit and that of the room is unlikely to occur in patients with Raynaud's phenomenon or HAVS. A temperature gain of > or =2.2 degrees C in the first 30 seconds on rewarming combined with a low baseline temperature strongly suggests HAVS. This modified cold provocation test may differentiate between patients with Raynaud's phenomenon, HAVS and controls but this observation requires independent verification in subjects not involved in litigation and tested in the same facility.

  2. Emperipolesis: An Unreported Novel Phenomenon in Oral Squamous Cell Carcinoma.

    PubMed

    Sarode, Gargi S; Sarode, Sachin C; Patil, Shankargouda

    2017-04-01

    Emperipolesis is a phenomenon characterized by engulfment of hematopoietic cells by megakaryocytes, monocytes, fibroblasts, and malignant cells within their cytoplasm. This phenomenon has been reported in various physiological and pathological conditions including malignancies. However, emperipolesis has never been reported in oral squamous cell carcinoma (OSCC) till date. We have analyzed histopathological slides of 56 cases of OSCC to see lymphocyte engulfment by tumor cells. Five cases showing features of this phenomenon were observed. Lymphocytes were typically identified as small round cells with oval nuclei and scanty cytoplasm. Both partial and complete engulfment of lymphocytes by tumor cells was appreciated. Nuclei of the host tumor cells were crescent shaped and illustrated small concave indentation, so as to accommodate the internalized lymphocyte. The intercellular bridges were not seen between the internalized cell and the host cell. There were no signs of degeneration appreciable in either cell, thus ruling out the possibility of cannibalism phenomenon. Although emperipolesis is a well-known phenomenon in pathology, this is the first report showing its evidence in OSCC.

  3. The post-mortem pink teeth phenomenon: a case report.

    PubMed

    Soriano, Evelyne-Pessoa; Carvalho, Marcus-Vitor-Diniz de; Santos, Francisco-Bernardo Dos; Mendoza, Clóvis-César de; Araújo, Maria-do Socorro-Dantas de; Campello, Reginaldo-Inojosa-Carneiro

    2009-07-01

    This study presents the case of the post-mortem pink teeth phenomenon observed during an autopsy procedure performed on the body of a man who was kidnapped and murdered approximately 30 days before the examination. The corpse was in an advanced stage of decomposition and putrefaction. Both maxillary and jaw bones were intact, as well as the permanent teeth which presented the "pink teeth phenomenon", probably due to a haemorrhage in the pulp chambers. The pink discolouration was most pronounced at the neck of the teeth. The cause of death was asphyxia. Although the examiners stressed that post-mortem pink teeth must not be considered as a reliable odontological parameter for determining the cause of death, the results of other studies have shown that the pink teeth phenomenon is a common finding related to cases of asphyxia such as strangulation, drowning or suffocation. Thus, the pink teeth phenomenon must be studied in order to determine its role as a post-mortem finding. As of now, an exact relationship between the cause of death and this phenomenon remains unknown.

  4. Review of West Nile virus circulation and outbreak risk in Madagascar: Entomological and ornithological perspectives

    PubMed Central

    Tantely, Michaël Luciano; Goodman, Steven M.; Rakotondranaivo, Tsirinaina; Boyer, Sébastien

    2016-01-01

    West Nile fever (WNF) is a zoonotic disease, occurring nearly globally. In Madagascar, West Nile virus (WNV) was first detected in 1978 from wild birds and the virus is currently distributed across the island, but no epidemic or epizootic period has been recorded. One fatal human case of WNV infection was reported in 2011, suggesting a “tip of the iceberg” phenomenon of a possible WNF epidemic/epizootic on the island. The main objective of this literature-based survey is to review patterns of WNV circulation in Madagascar from the entomological and ornithological points of view. Among the 235 mosquito species described from Madagascar, 29 species are widely associated with WNV infection; 16 of them are found naturally infected with WNV on the island and categorized into major, candidate, and potential vectors of WNV according to their vector capacity. This study upholds the hypothesis that WNV enzooticity is independent of annual movements of migratory birds passing through Madagascar. Moreover, the lack of regular migratory bird flux between Africa and Madagascar would reduce the probability of transmission and the subsequent reintroduction of the virus into locally occurring mosquito species. Given that Palearctic migratory birds are strongly implicated in the transmission of WNV, we highlight notable differences in the movements and species diversity of these birds in Madagascar as compared to eastern and northern Africa. Risk factors from this two-pronged approach are presented for the emergence of WNF outbreak. PMID:27849515

  5. Deviation from Power Law Behavior in Landslide Phenomenon

    NASA Astrophysics Data System (ADS)

    Li, L.; Lan, H.; Wu, Y.

    2013-12-01

    Power law distribution of magnitude is widely observed in many natural hazards (e.g., earthquake, floods, tornadoes, and forest fires). Landslide is unique as the size distribution of landslide is characterized by a power law decrease with a rollover in the small size end. Yet, the emergence of the rollover, i.e., the deviation from power law behavior for small size landslides, remains a mystery. In this contribution, we grouped the forces applied on landslide bodies into two categories: 1) the forces proportional to the volume of failure mass (gravity and friction), and 2) the forces proportional to the area of failure surface (cohesion). Failure occurs when the forces proportional to volume exceed the forces proportional to surface area. As such, given a certain mechanical configuration, the failure volume to failure surface area ratio must exceed a corresponding threshold to guarantee a failure. Assuming all landslides share a uniform shape, which means the volume to surface area ratio of landslide regularly increase with the landslide volume, a cutoff of landslide volume distribution in the small size end can be defined. However, in realistic landslide phenomena, where heterogeneities of landslide shape and mechanical configuration are existent, a simple cutoff of landslide volume distribution does not exist. The stochasticity of landslide shape introduce a probability distribution of the volume to surface area ratio with regard to landslide volume, with which the probability that the volume to surface ratio exceed the threshold can be estimated regarding values of landslide volume. An experiment based on empirical data showed that this probability can induce the power law distribution of landslide volume roll down in the small size end. We therefore proposed that the constraints on the failure volume to failure surface area ratio together with the heterogeneity of landslide geometry and mechanical configuration attribute for the deviation from power law

  6. Recent progress in circulation control aerodynamics

    NASA Technical Reports Server (NTRS)

    Nielsen, Jack N.; Biggers, James C.

    1987-01-01

    A workshop on circulation control aerodynamics was held on February 19-21, 1986 at NASA Ames Research Center, Moffett Field, CA. The subjects covered were viscosity and turbulence of Coanda jets, circulation control airfoils, airfoil theory, circulation control airfoil and wing experiments, circulation control rotor theory, X-Wing technology, and fixed-wing technology. The unclassified papers of the Workshop are reviewed in this paper, and Workshop recommendations for future research and development on circulation control are presented.

  7. [Circulating nucleic acids and infertility].

    PubMed

    Scalici, E; Mullet, T; Ferrières Hoa, A; Gala, A; Loup, V; Anahory, T; Belloc, S; Hamamah, S

    2015-09-01

    Circulating nucleic acids (cell-free DNA and microRNAs) have for particularity to be easily detectable in the biological fluids of the body. Therefore, they constitute biomarkers of interest in female and male infertility care. Indeed, in female, they can be used to detect ovarian reserve disorders (polycystic ovary syndrome and low functional ovarian reserve) as well as to assess follicular microenvironment quality. Moreover, in men, their expression levels can vary in case of spermatogenesis abnormalities. Finally, circulating nucleic acids have also the ability to predict successfully the quality of in vitro embryo development. Their multiple contributions during assisted reproductive technology (ART) make of them biomarkers of interest, for the development of new diagnostic and/or prognostic tests, applied to our specialty. Circulating nucleic acids would so offer the possibility of personalized medical care for infertile couples in ART.

  8. Bandwidth broadening for stripline circulator

    NASA Astrophysics Data System (ADS)

    Chao, Hsien-Wen; Wu, Shi-Yao; Chang, Tsun-Hsu

    2017-02-01

    This work provides a detailed analysis and simulation to demonstrate how to broaden the operating bandwidth of a circulator. A double-Y junction circulator is designed, and the shape of the central stripline is optimized with the knowledge of a modified equation. The equation predicts two resonant conditions. The overlapping of the two resonant conditions jointly constitutes the broad bandwidth. The bias magnetic field is simulated and then used in full electromagnetic-wave simulation. The designed circulator was fabricated in the S-band for communication purpose. The measured results agree very well with simulation. The overall operation range is from 1643 to 2027 MHz with the insertion loss less than 0.35 dB, reflection, and isolation better than 20 dB. The mechanism will be discussed.

  9. Noise Reduction Through Circulation Control

    NASA Technical Reports Server (NTRS)

    Munro, Scott E.; Ahuja, K. K.; Englar, Robert J.

    2005-01-01

    Circulation control technology uses tangential blowing around a rounded trailing edge or a leading edge to change the force and moment characteristics of an aerodynamic body. This technology has been applied to circular cylinders, wings, helicopter rotors, and even to automobiles for improved aerodynamic performance. Only limited research has been conducted on the acoustic of this technology. Since wing flaps contribute to the environmental noise of an aircraft, an alternate blown high lift system without complex mechanical flaps could prove beneficial in reducing the noise of an approaching aircraft. Thus, in this study, a direct comparison of the acoustic characteristics of high lift systems employing a circulation control wing configuration and a conventional wing flapped configuration has been made. These results indicate that acoustically, a circulation control wing high lift system could be considerably more acceptable than a wing with conventional mechanical flaps.

  10. Ringing phenomenon based whispering-gallery-mode sensing

    NASA Astrophysics Data System (ADS)

    Ye, Ming-Yong; Shen, Mei-Xia; Lin, Xiu-Min

    2016-01-01

    Highly sensitive sensing is one of the most important applications of whispering-gallery-mode (WGM) microresonators, which is usually accomplished through a tunable continuous-wave laser sweeping over a whispering-gallery mode with the help of a fiber taper in a relative slow speed. It is known that if a tunable continuous-wave laser sweeps over a high quality whispering-gallery mode in a fast speed, a ringing phenomenon will be observed. The ringing phenomenon in WGM microresonators is mainly used to measure the Q factors and mode-coupling strengths. Here we experimentally demonstrate that the WGM sensing can be achieved based on the ringing phenomenon. This kind of sensing is accomplished in a much shorter time and is immune to the noise caused by the laser wavelength drift.

  11. Self-Propelled Hovercraft Based on Cold Leidenfrost Phenomenon.

    PubMed

    Shi, Meng; Ji, Xing; Feng, Shangsheng; Yang, Qingzhen; Lu, Tian Jian; Xu, Feng

    2016-06-24

    The Leidenfrost phenomenon of liquid droplets levitating and dancing when placed upon a hot plate due to propulsion of evaporative vapor has been extended to many self-propelled circumstances. However, such self-propelled Leidenfrost devices commonly need a high temperature for evaporation and a structured solid substrate for directional movements. Here we observed a "cold Leidenfrost phenomenon" when placing a dry ice device on the surface of room temperature water, based on which we developed a controllable self-propelled dry ice hovercraft. Due to the sublimated vapor, the hovercraft could float on water and move in a programmable manner through designed structures. As demonstrations, we showed that the hovercraft could be used as a cargo ship or a petroleum contamination collector without consuming external power. This phenomenon enables a novel way to utilize programmable self-propelled devices on top of room temperature water, holding great potential for applications in energy, chemical engineering and biology.

  12. Statistical Agent Based Modelization of the Phenomenon of Drug Abuse

    NASA Astrophysics Data System (ADS)

    di Clemente, Riccardo; Pietronero, Luciano

    2012-07-01

    We introduce a statistical agent based model to describe the phenomenon of drug abuse and its dynamical evolution at the individual and global level. The agents are heterogeneous with respect to their intrinsic inclination to drugs, to their budget attitude and social environment. The various levels of drug use were inspired by the professional description of the phenomenon and this permits a direct comparison with all available data. We show that certain elements have a great importance to start the use of drugs, for example the rare events in the personal experiences which permit to overcame the barrier of drug use occasionally. The analysis of how the system reacts to perturbations is very important to understand its key elements and it provides strategies for effective policy making. The present model represents the first step of a realistic description of this phenomenon and can be easily generalized in various directions.

  13. Kernohan's phenomenon associated with left ruptured occipital arteriovenous malformation.

    PubMed

    Fujimoto, A; Sato, H; Katayama, W; Nakai, K; Tsunoda, T; Kobayashi, E; Nose, T

    2004-05-01

    A 23-year-old woman presented with ipsilateral hemiparesia due to rupture of a left occipital arteriovenous malformation (AVM). Emergency decompression (the onset-operation interval was 46 minutes,) was carried out and the patient could leave the hospital upon recovery without neurological deficits. In general, Kernohan's phenomenon is caused by the gradual displacement of the cerebral peduncle against the tentorial edge caused by compression by the contralateral mass. This phenomenon is very rare among the cases with spontaneous intracranial hemorrhage and only three cases including the present one have been reported in the literature. In all cases the onset-operation intervals of were very short. Kernohan's phenomenon associated with a ruptured AVM is a rare condition and emergency decompression is required.

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

    PubMed

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

    2008-01-01

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

  15. High prevalence of isolated sleep paralysis: kanashibari phenomenon in Japan.

    PubMed

    Fukuda, K; Miyasita, A; Inugami, M; Ishihara, K

    1987-06-01

    In Japan, a set of experiences called kanashibari is considered identical with isolated sleep paralysis. We investigated this phenomenon by means of a questionnaire administered to 635 college students (390 men and 245 women). Of all subjects, about 40% had experienced at least one episode of kanashibari [subjects of K(+)]. Therefore, isolated sleep paralysis is apparently a more common phenomenon than is usually appreciated. About half of the subjects of K(+) reported that they had been under "physical or psychological stress" or in a "disturbed sleep and wakefulness cycle" immediately before the episode. Many subjects of K(+) experienced the first episode in adolescence. In the distribution of age of first attack, the peak occurred at an earlier age in women subjects than in men subjects. These findings suggest that two factors influence the occurrence of the phenomenon. One is exogenous physical or psychological load and the other is endogenous biological development.

  16. Ringing phenomenon based whispering-gallery-mode sensing

    PubMed Central

    Ye, Ming-Yong; Shen, Mei-Xia; Lin, Xiu-Min

    2016-01-01

    Highly sensitive sensing is one of the most important applications of whispering-gallery-mode (WGM) microresonators, which is usually accomplished through a tunable continuous-wave laser sweeping over a whispering-gallery mode with the help of a fiber taper in a relative slow speed. It is known that if a tunable continuous-wave laser sweeps over a high quality whispering-gallery mode in a fast speed, a ringing phenomenon will be observed. The ringing phenomenon in WGM microresonators is mainly used to measure the Q factors and mode-coupling strengths. Here we experimentally demonstrate that the WGM sensing can be achieved based on the ringing phenomenon. This kind of sensing is accomplished in a much shorter time and is immune to the noise caused by the laser wavelength drift. PMID:26796871

  17. Tears of wine: new insights on an old phenomenon

    NASA Astrophysics Data System (ADS)

    Venerus, David C.; Nieto Simavilla, David

    2015-11-01

    Anyone who has enjoyed a glass of wine has undoubtedly noticed the regular pattern of liquid beads that fall along the inside of the glass, or ‘tears of wine.’ The phenomenon is the result of a flow against gravity along the liquid film on the glass, which is induced by an interfacial tension gradient. It is generally accepted that the interfacial tension gradient is due to a composition gradient resulting from the evaporation of ethanol. We re-examine the tears of wine phenomenon and investigate the importance of thermal effects, which previously have been ignored. Using a novel experiment and simple model we find that evaporative cooling contributes significantly to the flow responsible for wine tears, and that this phenomenon occurs primarily because of the thermodynamic behavior of ethanol-water mixtures. Also, the regular pattern of tear formation is identified as a well-known hydrodynamic instability.

  18. Tears of wine: new insights on an old phenomenon

    PubMed Central

    Venerus, David C.; Nieto Simavilla, David

    2015-01-01

    Anyone who has enjoyed a glass of wine has undoubtedly noticed the regular pattern of liquid beads that fall along the inside of the glass, or ‘tears of wine.’ The phenomenon is the result of a flow against gravity along the liquid film on the glass, which is induced by an interfacial tension gradient. It is generally accepted that the interfacial tension gradient is due to a composition gradient resulting from the evaporation of ethanol. We re-examine the tears of wine phenomenon and investigate the importance of thermal effects, which previously have been ignored. Using a novel experiment and simple model we find that evaporative cooling contributes significantly to the flow responsible for wine tears, and that this phenomenon occurs primarily because of the thermodynamic behavior of ethanol-water mixtures. Also, the regular pattern of tear formation is identified as a well-known hydrodynamic instability. PMID:26548566

  19. Circulating a Good Service Model at Its Core: Circulation!

    ERIC Educational Resources Information Center

    Hernandez, Edmee Sofia; Germain, Carol Anne, Ed.

    2009-01-01

    Circulation is the library's tireless foot soldier: it serves as the front gate to the library's services and resources. This service point is where most patrons enter and leave; and experience their first and last impressions--impressions that linger. In an age when academic libraries are facing meager budgets and declining usage statistics, this…

  20. Circulating a Good Service Model at Its Core: Circulation!

    ERIC Educational Resources Information Center

    Hernandez, Edmee Sofia; Germain, Carol Anne, Ed.

    2009-01-01

    Circulation is the library's tireless foot soldier: it serves as the front gate to the library's services and resources. This service point is where most patrons enter and leave; and experience their first and last impressions--impressions that linger. In an age when academic libraries are facing meager budgets and declining usage statistics, this…