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Sample records for events precede calcium

  1. Calcium ion currents mediating oocyte maturation events

    PubMed Central

    Tosti, Elisabetta

    2006-01-01

    During maturation, the last phase of oogenesis, the oocyte undergoes several changes which prepare it to be ovulated and fertilized. Immature oocytes are arrested in the first meiotic process prophase, that is morphologically identified by a germinal vesicle. The removal of the first meiotic block marks the initiation of maturation. Although a large number of molecules are involved in complex sequences of events, there is evidence that a calcium increase plays a pivotal role in meiosis re-initiation. It is well established that, during this process, calcium is released from the intracellular stores, whereas less is known on the role of external calcium entering the cell through the plasma membrane ion channels. This review is focused on the functional role of calcium currents during oocyte maturation in all the species, from invertebrates to mammals. The emerging role of specific L-type calcium channels will be discussed. PMID:16684344

  2. Kickoff to Conflict: A Sequence Analysis of Intra-State Conflict-Preceding Event Structures

    PubMed Central

    D'Orazio, Vito; Yonamine, James E.

    2015-01-01

    While many studies have suggested or assumed that the periods preceding the onset of intra-state conflict are similar across time and space, few have empirically tested this proposition. Using the Integrated Crisis Early Warning System's domestic event data in Asia from 1998–2010, we subject this proposition to empirical analysis. We code the similarity of government-rebel interactions in sequences preceding the onset of intra-state conflict to those preceding further periods of peace using three different metrics: Euclidean, Levenshtein, and mutual information. These scores are then used as predictors in a bivariate logistic regression to forecast whether we are likely to observe conflict in neither, one, or both of the states. We find that our model accurately classifies cases where both sequences precede peace, but struggles to distinguish between cases in which one sequence escalates to conflict and where both sequences escalate to conflict. These findings empirically suggest that generalizable patterns exist between event sequences that precede peace. PMID:25951105

  3. Mal-Adaptation of Event-Related EEG Responses Preceding Performance Errors

    PubMed Central

    Eichele, Heike; Juvodden, Hilde T.; Ullsperger, Markus; Eichele, Tom

    2010-01-01

    Recent EEG and fMRI evidence suggests that behavioral errors are foreshadowed by systematic changes in brain activity preceding the outcome by seconds. In order to further characterize this type of error precursor activity, we investigated single-trial event-related EEG activity from 70 participants performing a modified Eriksen flanker task, in particular focusing on the trial-by-trial dynamics of a fronto-central independent component that previously has been associated with error and feedback processing. The stimulus-locked peaks in the N2 and P3 latency range in the event-related averages showed expected compatibility and error-related modulations. In addition, a small pre-stimulus negative slow wave was present at erroneous trials. Significant error-preceding activity was found in local stimulus sequences with decreased conflict in the form of less negativity at the N2 latency (310–350 ms) accumulating across five trials before errors; concomitantly response times were speeding across trials. These results illustrate that error-preceding activity in event-related EEG is associated with the performance monitoring system and we conclude that the dynamics of performance monitoring contribute to the generation of error-prone states in addition to the more remote and indirect effects in ongoing activity such as posterior alpha power in EEG and default mode drifts in fMRI. PMID:20740080

  4. Intense foreshocks and a slow slip event preceded the 2014 Iquique Mw 8.1 earthquake.

    PubMed

    Ruiz, S; Metois, M; Fuenzalida, A; Ruiz, J; Leyton, F; Grandin, R; Vigny, C; Madariaga, R; Campos, J

    2014-09-05

    The subduction zone in northern Chile is a well-identified seismic gap that last ruptured in 1877. The moment magnitude (Mw) 8.1 Iquique earthquake of 1 April 2014 broke a highly coupled portion of this gap. To understand the seismicity preceding this event, we studied the location and mechanisms of the foreshocks and computed Global Positioning System (GPS) time series at stations located on shore. Seismicity off the coast of Iquique started to increase in January 2014. After 16 March, several Mw > 6 events occurred near the low-coupled zone. These events migrated northward for ~50 kilometers until the 1 April earthquake occurred. On 16 March, on-shore continuous GPS stations detected a westward motion that we model as a slow slip event situated in the same area where the mainshock occurred.

  5. A very long-term transient event preceding the 2011 Tohoku earthquake.

    PubMed

    Yokota, Yusuke; Koketsu, Kazuki

    2015-01-06

    Geodetic transients have been observed in various subduction zones. The 2011 Tohoku earthquake occurred in one of the most active subduction zones globally, the Japan Trench subduction zone (JTSZ). However, no geodetic transient (except afterslip and so on) had been reported in the JTSZ before the Tohoku earthquake. Here we show that a large transient event, with duration longer than any reported previously, occurred in the JTSZ preceding the Tohoku earthquake. We calculate tectonic deformations at Global Positioning System stations along the JTSZ by removing the effects of nearby M(w) 6-8 earthquakes. We identify temporal changes in these deformations, deriving 9-year deviation records from regular deformations due to slip deficit at the plate boundary. We perform an inversion of the deviations to obtain the source model of their root event. The relationship between the obtained transient event and Tohoku earthquake is shown through Coulomb stress change and seismic supercycle simulation.

  6. Primary ultrafast events preceding the photoinduced proton transfer from pyranine to water

    NASA Astrophysics Data System (ADS)

    Tran-Thi, T.-H.; Gustavsson, T.; Prayer, C.; Pommeret, S.; Hynes, James T.

    2000-10-01

    Femtosecond fluorescence and absorption spectroscopies are used to probe the early events of the photoinduced proton transfer (PT) from pyranine to water. The process is found to involve two ultrafast steps (300 fs and 2.5 ps) which precede the relatively slow (87 ps) PT step. From the comparative study of the properties of the excited acid and its conjugate anion in various aqueous and alcoholic media, these ultrafast steps are identified as the solvation dynamics of the locally excited (LE) state of the acid and its subsequent relaxation to an intermediate electronic state, whose nature is discussed.

  7. Automated Discovery and Modeling of Sequential Patterns Preceding Events of Interest

    NASA Technical Reports Server (NTRS)

    Rohloff, Kurt

    2010-01-01

    The integration of emerging data manipulation technologies has enabled a paradigm shift in practitioners' abilities to understand and anticipate events of interest in complex systems. Example events of interest include outbreaks of socio-political violence in nation-states. Rather than relying on human-centric modeling efforts that are limited by the availability of SMEs, automated data processing technologies has enabled the development of innovative automated complex system modeling and predictive analysis technologies. We introduce one such emerging modeling technology - the sequential pattern methodology. We have applied the sequential pattern methodology to automatically identify patterns of observed behavior that precede outbreaks of socio-political violence such as riots, rebellions and coups in nation-states. The sequential pattern methodology is a groundbreaking approach to automated complex system model discovery because it generates easily interpretable patterns based on direct observations of sampled factor data for a deeper understanding of societal behaviors that is tolerant of observation noise and missing data. The discovered patterns are simple to interpret and mimic human's identifications of observed trends in temporal data. Discovered patterns also provide an automated forecasting ability: we discuss an example of using discovered patterns coupled with a rich data environment to forecast various types of socio-political violence in nation-states.

  8. Seagrass Proliferation Precedes Mortality during Hypo-Salinity Events: A Stress-Induced Morphometric Response

    PubMed Central

    Collier, Catherine J.; Villacorta-Rath, Cecilia; van Dijk, Kor-jent; Takahashi, Miwa; Waycott, Michelle

    2014-01-01

    Halophytes, such as seagrasses, predominantly form habitats in coastal and estuarine areas. These habitats can be seasonally exposed to hypo-salinity events during watershed runoff exposing them to dramatic salinity shifts and osmotic shock. The manifestation of this osmotic shock on seagrass morphology and phenology was tested in three Indo-Pacific seagrass species, Halophila ovalis, Halodule uninervis and Zostera muelleri, to hypo-salinity ranging from 3 to 36 PSU at 3 PSU increments for 10 weeks. All three species had broad salinity tolerance but demonstrated a moderate hypo-salinity stress response – analogous to a stress induced morphometric response (SIMR). Shoot proliferation occurred at salinities <30 PSU, with the largest increases, up to 400% increase in shoot density, occurring at the sub-lethal salinities <15 PSU, with the specific salinity associated with peak shoot density being variable among species. Resources were not diverted away from leaf growth or shoot development to support the new shoot production. However, at sub-lethal salinities where shoots proliferated, flowering was severely reduced for H. ovalis, the only species to flower during this experiment, demonstrating a diversion of resources away from sexual reproduction to support the investment in new shoots. This SIMR response preceded mortality, which occurred at 3 PSU for H. ovalis and 6 PSU for H. uninervis, while complete mortality was not reached for Z. muelleri. This is the first study to identify a SIMR in seagrasses, being detectable due to the fine resolution of salinity treatments tested. The detection of SIMR demonstrates the need for caution in interpreting in-situ changes in shoot density as shoot proliferation could be interpreted as a healthy or positive plant response to environmental conditions, when in fact it could signal pre-mortality stress. PMID:24705377

  9. Survey of DMSP Charging Events During the Period Preceding Cycle 23 Solar Maximum

    NASA Technical Reports Server (NTRS)

    Parker, Linda Neergaard; Minow, Joseph I.

    2013-01-01

    It has been well established that POLAR orbiting satellites can see mild to severe charging levels during solar minimum conditions (Frooninckx and Sojka, 1992, Anderson and Koons, 1996, Anderson, 2012). However, spacecraft operations during solar maximum cannot be considered safe from auroral charging. Recently, we have seen examples of high level charging during the recent approach to solar maximum. We present here a survey of charging events seen by the Defense Meteorological Satellite Program (DMSP) satellites (F16, F17) during the solstices of 2011 and 2012. In this survey, we summarize the condition necessary for charging to occur in this environment, we describe how the lower than normal maximum conditions are conducive to the environment conditions necessary for charging in the POLAR orbit, and we show examples of the more extreme charging events, sometimes exceeding 1 kV, during this time period. We also show examples of other interesting phenomenological events seen in the DMSP data, but which are not considered surface charging events, and discuss the differences.

  10. Large-scale Slow Slip Event Preceding the 2011 Tohoku Earthquake

    NASA Astrophysics Data System (ADS)

    Koketsu, K.; Yokota, Y.

    2013-12-01

    We carried out inversions of annual GEONET data (F3 displacements) observed by the Geospatial Information Authority of Japan from the opening of GEONET in 1996 to the 2011 Tohoku earthquake. We then obtained annual backslip (slip deficit) rate distributions, finding that the backslip had weakened and migrated at some time in 2002 or 2003 (Koketsu, Yokota, N. Kato, and T. Kato, 2012 AGU fall meeting). In this study, we are going back to the original GEONET data and examine whether the weakening and migration of backslip included in them were stationary or not. If they are confirmed to be stationary, we can relate them to a large-scale slow slip event. Since similar phenomena occurred from 2001 to 2004 in the Tokai district of Japan, we analyze the original GEONET data using such a method as Ozawa et al. (2002) applied for the Tokai phenomena. However, as the seismicity in the Tohoku and Kanto districts is higher than in the Tokai district, we have corrected the original data in advance by removing not only annual sinusoidal variations but also the effects of M 6 to 8 earthquakes. We first choose four GEONET stations where large weakening is observed, and derive average trends from the corrected data in 1996 to 2001 after we confirm stationary displacement rates during the period. When we subtract the average trends from the corrected data as shown in Fig. 1, we find flat lines up to some time in 2002 or 2003 and then eastward displacements in opposite direction to the backslip. Therefore, we perform regression analyses to obtain an inflection point between the flat lines and eastward displacements. The result indicates the inflection point to be located in May 2002. If the rates of the eastward displacements after May 2002 look stationary, a slow slip event can be considered to occur as in the Tokai district. Their plots actually show stationary rates except for increase at the time of the 2005 Miyagi-oki earthquake. We next perform the same analyses of the

  11. Person perception precedes theory of mind: an event related potential analysis.

    PubMed

    Wang, Y W; Lin, C D; Yuan, B; Huang, L; Zhang, W X; Shen, D L

    2010-09-29

    Prior to developing an understanding of another person's mental state, an ability termed "theory of mind" (ToM), a perception of that person's appearance and actions is required. However the relationship between this "person perception" and ToM is unclear. To investigate the time course of ToM and person perception, event-related potentials (ERP) were recorded while 17 normal adults received three kinds of visual stimuli: cartoons involving people (person perception cartoons), cartoons involving people and also requiring ToM for comprehension (ToM cartoons), and scene cartoons. We hypothesized that the respective patterns of brain activation would be different under these three stimuli, at different stages in time. Our findings supported this proposal: the peak amplitudes of P200 for scene cartoons were significantly lower than for person perception or ToM cartoons, while there were no significant differences between the latter two for P200. During the 1000-1300 ms epoch, the mean amplitudes of the late positive components (LPC) for person perception were more positive than for scene representation, while the mean amplitudes of the LPC for ToM were more positive than for person perception. The present study provides preliminary evidence of the neural dynamic that underlies the dissociation between person perception and ToM.

  12. TP53 mutations are early events in chronic lymphocytic leukemia disease progression and precede evolution to complex karyotypes.

    PubMed

    Lazarian, Gregory; Tausch, Eugen; Eclache, Virginie; Sebaa, Amel; Bianchi, Vincent; Letestu, Remi; Collon, Jean-Francois; Lefebvre, Valerie; Gardano, Laura; Varin-Blank, Nadine; Soussi, Thierry; Stilgenbauer, Stephen; Cymbalista, Florence; Baran-Marszak, Fanny

    2016-10-15

    TP53 abnormalities lead to resistance to purine analogues and are found in over 40% of patients with refractory chronic lymphocytic leukemia (CLL). At diagnosis, no more than 5% of patients carry the 17p deletion, most cases harbour mutations within the other TP53 allele. The incidence of a TP53 mutation as the only alteration is approximately 5%, but this depends on the sensitivity of the technique. Recently, having a complex karyotype has been considered a strong adverse prognostic factor. However, there are no longitudinal studies simultaneously examining the presence of the 17p deletion, TP53 mutations and karyotype abnormalities. We conducted a retrospective longitudinal study of 31 relapsed/refractory CLL patients. Two to six blood samples per patient were analyzed, with a median follow-up of 8 years. In this report, we assessed the sequence of events of TP53 clonal evolution and correlated the presence of TP53 abnormalities to genetic instability during progression and treatment. Next-generation sequencing allowed the early detection of TP53 mutated clones and was able to be performed on a routine basis, demonstrating an excellent correlation between the Illumina and Ion Torrent technologies. We concluded that TP53 mutations are early events and precede clonal evolution to complex karyotypes. We strongly recommend the early and iterated detection of TP53 mutations in progressive cases.

  13. Calcium utilization by quail embryos during activities preceding space flight and during embryogenesis in microgravity aboard the orbital space station MIR.

    PubMed

    Orban, J I; Piert, S J; Guryeva, T S; Hester, P Y

    1999-10-01

    A series of studies were conducted to determine the effect of activities preceding spaceflight and during space-flight on calcium utilization during quail embryonic development. In the pre-space trials, fertile quail eggs were subjected to pre-flight dynamics including forces of centrifugation, vibration, or a combination of vibration and centrifugation prior to incubation for 6 or 16 days. Quail eggs were also tested for survivability in a refrigerator stowage kit for eggs (RSKE) which was subsequently used to transport the eggs to space. Eggs in the RSKE were subjected to shuttle launch dynamics including G force and random vibration profiles. The space-flight trial involved 48 quail eggs launched on space shuttle Flight STS-76 which were subsequently incubated in a Slovakian incubator onboard space station, MIR. Two ground control trials, each with 48 eggs with and without exposure to shuttle launch dynamics were initiated 5 days post-launch. Eggshells from all study trials were retrieved and analyzed for calcium content. Results showed that neither pre-flight activities nor shuttle launch dynamics had an effect on calcium utilization by developing embryos. However, calcium utilization by developing embryos incubated in microgravity was impaired by 12.6% when compared to embryos incubated on earth under laboratory control environment. This impairment was believed to be due to unidentified factors of the microgravity environment.

  14. Integration of sensory information precedes the sensation of vection: a combined behavioral and event-related brain potential (ERP) study.

    PubMed

    Keshavarz, Behrang; Berti, Stefan

    2014-02-01

    Illusory self-motion (known as vection) describes the sensation of ego-motion in the absence of physical movement. Vection typically occurs in stationary observers being exposed to visual information that suggest self-motion (e.g. simulators, virtual reality). In the present study, we tested whether sensory integration of visual information triggers vection: participants (N=13) perceived patterns of moving altered black-and-white vertical stripes on a screen that was divided into a central and a surrounding peripheral visual field. In both fields the pattern was either moving or stationary, resulting in four combinations of central and peripheral motions: (1) central and peripheral stripes moved into the same direction, (2) central and peripheral stripes moved in opposite directions, or (3) either the central or (4) the peripheral stripes were stable while the other stripes were in motion. This stimulation induced vection: Results showed significantly higher vection ratings when the stationary center of the pattern was surrounded by a moving periphery. Event-related potentials mirrored this finding: The occipital N2 was largest with stationary central and moving peripheral stripes. Our findings suggest that sensory integration of peripheral and central visual information triggers the perception of vection. Furthermore, we found evidence that neural processes precede the subjective perception of vection strength prior to the actual onset of vection. We will discuss our findings with respect to the role of stimulus eccentricity, stimulus' depth, and neural correlates involved during the genesis of vection.

  15. Cinacalcet, dialysate calcium concentration, and cardiovascular events in the EVOLVE trial.

    PubMed

    Pun, Patrick H; Abdalla, Safa; Block, Geoffrey A; Chertow, Glenn M; Correa-Rotter, Ricardo; Dehmel, Bastian; Drüeke, Tilman B; Floege, Jürgen; Goodman, William G; Herzog, Charles A; London, Gerard M; Mahaffey, Kenneth W; Moe, Sharon M; Parfrey, Patrick S; Wheeler, David C; Middleton, John P

    2016-07-01

    Among patients receiving hemodialysis, abnormalities in calcium regulation have been linked to an increased risk of cardiovascular events. Cinacalcet lowers serum calcium concentrations through its effect on parathyroid hormone secretion and has been hypothesized to reduce the risk of cardiovascular events. In observational cohort studies, prescriptions of low dialysate calcium concentration and larger observed serum-dialysate calcium gradients have been associated with higher risks of in-dialysis facility or peri-dialytic sudden cardiac arrest. We performed this study to examine the risks associated with dialysate calcium and serum-dialysate gradients among participants in the Evaluation of Cinacalcet Hydrochloride Therapy to Lower Cardiovascular Events (EVOLVE) trial. In EVOLVE, 3883 hemodialysis patients were randomized 1:1 to cinacalcet or placebo. Dialysate calcium was administered at the discretion of treating physicians. We examined whether baseline dialysate calcium concentration or the serum-dialysate calcium gradient modified the effect of cinacalcet on the following adjudicated endpoints: (1) primary composite endpoint (death or first non-fatal myocardial infarction, hospitalization for unstable angina, heart failure, or peripheral vascular event); (2) cardiovascular death; and (3) sudden death. In EVOLVE, use of higher dialysate calcium concentrations was more prevalent in Europe and Latin America compared with North America. There was a significant fall in serum calcium concentration in the cinacalcet group; dialysate calcium concentrations were changed infrequently in both groups. There was no association between baseline dialysate calcium concentration or serum-dialysate calcium gradient and the endpoints examined. Neither the baseline dialysate calcium nor the serum-dialysate calcium gradient significantly modified the effects of cinacalcet on the outcomes examined. The effects of cinacalcet on cardiovascular death and major cardiovascular events

  16. Localised calcium release events in cells from the muscle of guinea-pig gastric fundus

    PubMed Central

    Parsons, S P; Bolton, T B

    2004-01-01

    After enzymatic dispersion of the muscle of the guinea-pig gastric fundus, single elongated cells were observed which differed from archetypal smooth muscle cells due to their knurled, tuberose or otherwise irregular surface morphology. These, but not archetypal smooth muscle cells, consistently displayed spontaneous localized (i.e. non-propagating) intracellular calcium ([Ca2+]i) release events. Such calcium events were novel in their magnitude and kinetic profiles. They included short transient events, plateau events and events which coalesced spatially or temporally (compound events). Quantitative analysis of the events with an automatic detection programme showed that their spatio-temporal characteristics (full width and full duration at half-maximum amplitude) were approximately exponentially distributed. Their amplitude distribution suggested the presence of two release modes. Carbachol application caused an initial cell-wide calcium transient followed by an increase in localized calcium release events. Pharmacological analysis suggested that localized calcium release was largely dependent on external calcium entry acting on both inositol trisphosphate receptors (IP3Rs) and ryanodine receptors (RyRs) to release stored calcium. Nominally calcium-free external solution immediately and reversibly abolished all localized calcium release without blocking the initial transient calcium release response to carbachol. This was inhibited by 2-APB (100 μm), ryanodine (10 or 50 μm) or U-73122 (1 μm). 2-APB (100 μm), xestospongin C (XeC, 10 μm) or U-73122 (1 μm) blocked both spontaneous localized calcium release and localized release stimulated by 10 μm carbachol. Ryanodine (50 μm) also inhibited spontaneous release, but enhanced localized release in response to carbachol. This study represents the first characterization of localized calcium release events in cells from the gastric fundus. PMID:14608011

  17. Wnt11-R signaling regulates a calcium sensitive EMT event essential for dorsal fin development of Xenopus

    PubMed Central

    Garriock, Robert J.; Krieg, Paul A.

    2007-01-01

    In the frog embryo, a sub-population of trunk neural crest (NC) cells undergoes a dorsal route of migration to contribute to the mesenchyme in the core of the dorsal fin. Here we show that a second population of cells, originally located in the dorsomedial region of the somite, also contributes to the fin mesenchyme. We find that the frog orthologue of Wnt11 (Wnt11-R) is expressed in both the NC and somite cell populations that migrate into the fin matrix. Wnt11-R is expressed prior to migration and persists in the mesenchymal cells after they have distributed throughout the fin. Loss of function studies demonstrate that Wnt11-R activity is required for an epithelial to mesenchymal transformation (EMT) event that precedes migration of cells into the fin matrix. In Wnt11-R depleted embryos, the absence of fin core cells leads to defective dorsal fin development and to collapse of the fin structure. Experiments using small molecule inhibitors indicate that dorsal migration of fin core cells depends on calcium signaling through calcium/calmodulin-dependent kinase II (CaMKII). In Wnt11-R depleted embryos, normal migration of NC cells and dorsal somite cells into the fin and normal fin development can be rescued by stimulation of calcium release. These studies are consistent with a model in which Wnt11-R signaling, via a downstream calcium pathway, regulates fin cell migration and, more generally, indicates a role for non-canonical Wnt signaling in regulation of EMT. PMID:17240368

  18. Recent Life Events Preceding Suicide Attempts in a Personality Disorder Sample: Findings from the Collaborative Longitudinal Personality Disorders Study

    ERIC Educational Resources Information Center

    Yen, Shirley; Pagano, Maria E.; Shea, Tracie M.; Grilo, Carlos M.; Gunderson, John G.; Skodol, Andrew E.; McGlashan, Thomas H.; Sanislow, Charles A.; Bender, Donna S.

    2005-01-01

    Few studies have examined the relationship between life events, suicide attempts, and personality disorders (PDs), in spite of the strong associations between PDs and suicidal behavior, and the poor coping strategies often exhibited by these individuals. The authors examined whether participants with PDs who attempted suicide during the first 3…

  19. Does calcium intake affect cardiovascular risk factors and/or events?

    PubMed

    Torres, Márcia Regina Simas Gonçalves; Sanjuliani, Antonio Felipe

    2012-07-01

    Dietary intervention is an important approach in the prevention of cardiovascular disease. Over the last decade, some studies have suggested that a calcium-rich diet could help to control body weight, with anti-obesity effects. The potential mechanism underlying the impact of calcium on body fat has been investigated, but it is not fully understood. Recent evidence has also suggested that a calcium-rich diet could have beneficial effects on other cardiovascular risk factors, such as insulin resistance, dyslipidemia, hypertension and inflammatory states. In a series of studies, it was observed that a high intake of milk and/or dairy products (the main sources of dietary calcium) is associated with a reduction in the relative risk of cardiovascular disease. However, a few studies suggest that supplemental calcium (mainly calcium carbonate or citrate) may be associated with an increased risk of cardiovascular events. This review will discuss the available evidence regarding the relationship between calcium intake (dietary and supplemental) and different cardiovascular risk factors and/or events.

  20. Repeating LP events and increases in high-frequency seismic energy preceding the December 1999 eruption of the quiescently active Telica Volcano, Nicaragua

    NASA Astrophysics Data System (ADS)

    Rodgers, M.; Roman, D. C.; Geirsson, H.; Lafemina, P.; Muñoz, A.; Guzman, C.; Tenorio, V.

    2010-12-01

    Telica volcano, Nicaragua, is a ‘quiescently active’ basaltic andesite stratovolcano located in the Central American volcanic front. A high rate of long-period (LP) seismicity has been recorded at Telica since the installation of a single vertical-component 1 Hz seismic sensor (TELN) near its summit in 1993 by the Instituto Nicaragüense de Estudios Territoriales (INETER). Due to the continuously high rate of LPs at Telica, traditional methods of forecasting volcanic activity may not be applicable; therefore an understanding of the nature of precursory changes in Telica’s seismicity is necessary to accurately forecast future volcanic activity. A VEI 2 eruption of Telica occurred on the 29th December 1999, preceded by a series of small explosions between the 3rd-15th October 1999. Here we analyse an eight-month period of seismicity bracketing this activity, in an attempt to identify precursory changes with respect to background seismicity. Between August 1999 and March 2000 over 18,000 seismic events were recorded on TELN. We first calculated the dominant frequencies (i.e. frequency with dominant spectral energy) for all events recorded during this period. A time series of the dominant event frequencies between August 1999 and March 2000 shows a significant increase in the number of high frequency (> 5 Hz) events and, in LP events, a shift in the two dominant spectral energy peaks from 2 Hz and 4 Hz to 2 Hz and 3 Hz in the month before the October 1999 explosions. Next, we selected six representative eight-day periods, three from before the explosions and three from after, for multiplet analysis using waveform cross-correlation. Multiplet analysis of the six selected time periods reveal significant changes in behaviour. In period 1 (more than one month before the explosions) events are poorly correlated. In periods 2 and 3 (less than one month before the explosions) we identified several unique families of LP events, each having high cross-correlation values

  1. The new geophysical observatory in Northern Caucasus (Elbrus volcanic area) and results of studies of ULF magnetic variations preceding strong geodynamic events

    NASA Astrophysics Data System (ADS)

    Sobissevitch, Leonid E.; Sobissevitch, Alex L.; Kanonidi, Konstantin Kh.; Filippov, Ivan N.

    2010-05-01

    The new geophysical observatory for fundamental scientific studies of geophysical processes in the Elbrus volcanic area (Northern Caucasus) has been organized recently as a result of merging of five geophysical laboratories positioned round the Elbrus volcano and equipped with modern geophysical instruments including broadband tri-axial seismometers, quartz tilt-meters, magnetic variometers, geo-acoustic sensors, hi-precision distributed thermal sensors, gravimeters, and network-enabled data acquisition systems with precise GPS-timing and integrated monitoring of auxiliary parameters (variations on ambient humidity, atmospheric pressure etc). Two laboratories are located in the horizontal 4.3 km deep tunnel drilled under the mount Andyrchi, about 20 km from the Elbrus volcano. Analysis of multi-parameter streams of experimental data allows one to study the structure of geophysical wave fields induced by earthquakes and regional catastrophic events (including snow avalanches). On the basis of continuous observations carried out since 2007 there have been determined anomalous wave forms in ULF geomagnetic variations preceding strong seismic events with magnitude 7 or more. Mentioned wave forms may be natively related to processes of evolution of dilatational structures in a domain of forthcoming seismic event. Specific patterns in anomalous ULF wave forms are distinguished for undersea earthquakes and for earthquakes responsible for triggering tsunami events. Thus, it is possible to consider development of a future technology to suggest the possible area and the time frame of such class of catastrophic events with additional reference to forecast information (including acoustic, hydro-acoustic and geo-acoustic) being concurrently analyzed.

  2. Calcium

    MedlinePlus

    ... You'll also find calcium in broccoli and dark green, leafy vegetables (especially collard and turnip greens, ... can enjoy good sources of calcium such as dark green, leafy vegetables, broccoli, chickpeas, and calcium-fortified ...

  3. Coronary artery calcium and exercise electrocardiogram as predictors of coronary events in asymptomatic adults.

    PubMed

    Grossman, Chagai; Ehrlich, Shay; Shemesh, Joseph; Koren-Morag, Nira; Grossman, Ehud

    2015-03-15

    Early identification of patients at risk for coronary heart disease is crucial to formulate effective preventive strategies. The elevated risk of coronary artery calcium (CAC) for coronary heart disease is well established. Our aim was to estimate the relative risk of abnormal exercise electrocardiography (Ex ECG) in the presence of CAC. During the year 2001, 566 asymptomatic subjects performed a treadmill exercise test and consented to perform an unenhanced computed tomography to assess CAC. Patients were followed until December 2012. The relative risk for coronary events (acute myocardial infarction, hospitalization for unstable angina or coronary catheterization that resulted in angioplasty or coronary artery bypass surgery), of abnormal Ex ECG and presence of CAC were analyzed. An abnormal Ex ECG was found in 71 subjects (12.5%), and CAC was found in 286 subjects (50.5%). During a mean follow-up of 6.5 ± 3.3 years, 35 subjects experienced a first coronary event. In those without CAC, the rate of coronary events was low (4 of 280; 1.4%) regardless of the Ex ECG results. Subjects with both CAC and abnormal Ex ECG had the highest rate of coronary events (13 of 39; 33%). The adjusted hazard ratio for coronary events, in subjects with CAC, was 5.16 (95% confidence interval 2.52 to 10.60) in those with abnormal Ex ECG compared with those with normal Ex ECG. In conclusion, in subjects with CAC, further risk stratification can be achieved by an Ex ECG, whereas in those without CAC, an Ex ECG has less additional value in predicting coronary events.

  4. Calcium

    MedlinePlus

    ... milligrams) of calcium each day. Get it from: Dairy products. Low-fat milk, yogurt, cheese, and cottage ... lactase that helps digest the sugar (lactose) in dairy products, and may have gas, bloating, cramps, or ...

  5. Intracellular study of calcium-related events in cat magnocellular neuroendocrine cells.

    PubMed Central

    Fagan, M; Andrew, R D

    1991-01-01

    1. Magnocellular neuroendocrine cells (MNCs) in the supraoptic nucleus (SON) of mammals synthesize vasopressin or oxytocin and release these hormones systemically from their neurohypophysial axon terminals. In the rat, release is facilitated by bursts of action potentials generated by the MNC. However MNC units in the intact cat discharge more slowly and do not display the repetitive bursts (phasic firing) that promote vasopressin secretion. The reasons why these cat endocrine neurones differ so dramatically in their firing behaviour from the rat model were examined using intracellular recording. 2. Cat and rat MNCs displayed similar mean resting potentials approximating -60 mV, and were usually linear in their voltage-current relationship in the hyperpolarizing direction. However cat MNCs displayed a higher mean cell input resistance (301 M omega; n = 56) than those of rat (150 M omega; n = 105). 3. Calcium influx to cat MNCs during firing appeared comparable to rat based on (a) the similar range of action potential broadening observed during a spike train, (b) the shoulder on the action potential's falling phase which was blocked in low-Ca2+ saline, and (c) the ability to evoke tetrodotoxin (TTX)-insensitive spiking and non-synaptic depolarizing potentials, both calcium-mediated events observed in the rat. 4. In cat MNCs, a depolarizing current pulse (100-500 ms; 0.1-0.3 nA) elicited a train of action potentials followed by a prominent after-hyperpolarization (AHP) several times the duration of its counterpart in the rat. The AHP reversed near the equilibrium potential for K+, was not voltage dependent and represented an increased membrane conductance. It was suppressed in low-Ca2+ saline and completely eliminated by the calcium-activated potassium current (IK(Ca)) blockers apamin (100 nM) or d-tubocurarine (50-200 microM). Both blockers decreased spike frequency adaptation but did not induce bursting. Therefore the cat AHP probably represents a Ca(2+)-activated

  6. PRECEDE for Wellness.

    ERIC Educational Resources Information Center

    Bonaguro, John A.

    1981-01-01

    The PRECEDE model was developed for health educators in an effort to improve programs and to influence health behaviors. The model consists of several diagnostic phases: (1) epidemiological; (2) social; (3) behavioral; (4) educational; (5) administrative; and (6) evaluation. (JN)

  7. GPS constraints on the 2011-2012 Oaxaca slow slip event that preceded the 2012 March 20 Ometepec earthquake, southern Mexico

    NASA Astrophysics Data System (ADS)

    Graham, Shannon E.; DeMets, Charles; Cabral-Cano, Enrique; Kostoglodov, Vladimir; Walpersdorf, Andrea; Cotte, Nathalie; Brudzinski, Michael; McCaffrey, Robert; Salazar-Tlaczani, Luis

    2014-06-01

    We model measurements from 19 continuous GPS stations to determine the location and magnitude of a slow slip event (SSE) below southern Mexico that began in late 2011 and remained active up to the 2012 March 20 Mw = 7.4 Ometepec earthquake. Modelling of the space-time evolution of the SSE indicates that it initiated in 2011 November, migrated westward ˜2.6 km per day along the subduction interface, and reached the eventual earthquake source region ˜1 month before the 2012 March 20 earthquake occurred, in the waning stage of the SSE. The maximum slip for the SSE, ˜100 mm, occurred ˜100 km east of the earthquake rupture zone, in contrast to slip of 10-20 mm proximal to the Ometepec rupture zone. The SSE was focused downdip from the seismogenic zone everywhere along its ˜300-km-wide slip region and had a cumulative moment release of 3.0 × 1019 N•m (Mw = 6.9), similar to SSEs in 2004 and 2006 along this same area of the subduction interface. We calculate Coulomb stress changes as a result of slip during the SSE and find small but positive stress changes for the source region of the Ometepec earthquake. Our results are consistent with the hypothesis that the SSE triggered the Ometepec earthquake, although they are insufficient to demonstrate causality.

  8. Effect of calcium, bicarbonate, and albumin on capacitation-related events in equine sperm.

    PubMed

    Macías-García, B; González-Fernández, L; Loux, S C; Rocha, A M; Guimarães, T; Peña, F J; Varner, D D; Hinrichs, K

    2015-01-01

    Repeatable methods for IVF have not been established in the horse, reflecting the failure of standard capacitating media to induce changes required for fertilization capacity in equine sperm. One important step in capacitation is membrane cholesterol efflux, which in other species is triggered by cholesterol oxidation and is typically enhanced using albumin as a sterol acceptor. We incubated equine sperm in the presence of calcium, BSA, and bicarbonate, alone or in combination. Bicarbonate induced an increase in reactive oxygen species (ROS) that was abolished by the addition of calcium or BSA. Bicarbonate induced protein tyrosine phosphorylation (PY), even in the presence of calcium or BSA. Incubation at high pH enhanced PY but did not increase ROS production. Notably, no combination of these factors was associated with significant cholesterol efflux, as assessed by fluorescent quantitative cholesterol assay and confirmed by filipin staining. By contrast, sperm treated with methyl-β-cyclodextrin showed a significant reduction in cholesterol levels, but no significant increase in PY or ROS. Presence of BSA increased sperm binding to bovine zonae pellucidae in all three stallions. These results show that presence of serum albumin is not associated with a reduction in membrane cholesterol levels in equine sperm, highlighting the failure of equine sperm to exhibit core capacitation-related changes in a standard capacitating medium. These data indicate an atypical relationship among cholesterol efflux, ROS production, and PY in equine sperm. Our findings may help to elucidate factors affecting failure of equine IVF under standard conditions.

  9. Chronotropic incompetence precedes silent pulmonary embolism.

    PubMed

    Mahadevan, Karunasai; Silverman, Lawrence M; Becker, Daniel M

    2014-01-01

    A patient with recurrent pulmonary emboli collected heart rate data during exercise, which provided important premorbid clues to changes in cardiopulmonary exercise tolerance coincident with accrual of thrombus in the central circulation. On both occasions, chronotropic incompetence (CI) preceded the pulmonary emboli events. When patients with programmed exercise goals notice CI, they should seek professional guidance.

  10. Patterns of seismic activity preceding large earthquakes

    NASA Technical Reports Server (NTRS)

    Shaw, Bruce E.; Carlson, J. M.; Langer, J. S.

    1992-01-01

    A mechanical model of seismic faults is employed to investigate the seismic activities that occur prior to major events. The block-and-spring model dynamically generates a statistical distribution of smaller slipping events that precede large events, and the results satisfy the Gutenberg-Richter law. The scaling behavior during a loading cycle suggests small but systematic variations in space and time with maximum activity acceleration near the future epicenter. Activity patterns inferred from data on seismicity in California demonstrate a regional aspect; increased activity in certain areas are found to precede major earthquake events. One example is given regarding the Loma Prieta earthquake of 1989 which is located near a fault section associated with increased activity levels.

  11. Calcium isotope evidence for dramatic increase of continental weathering during the Toarcian oceanic anoxic event (Early Jurassic)

    NASA Astrophysics Data System (ADS)

    Brazier, Jean-Michel; Suan, Guillaume; Tacail, Théo; Simon, Laurent; Martin, Jeremy E.; Mattioli, Emanuela; Balter, Vincent

    2015-02-01

    The early Toarcian was punctuated by pulses of massive carbon injection that are thought to have triggered, through increased greenhouse conditions, elevated continental discharge and nutrient input, marine anoxia, seawater acidification and species extinctions. Nevertheless, the mode and tempo of changes in continental weathering across this interval remains highly debated, leading to considerable uncertainty about the main causes of these perturbations. In this study we present calcium isotope measurements (δ44/40Ca) of well-preserved brachiopods and bulk rock samples from the hemipelagic strata of Pliensbachian-Toarcian age of Peniche in Portugal in order to constrain changes in the calcium cycle and hence changes in continental weathering during the early Toarcian. The data reveal a similar trend as carbon isotope data from the same section and show negative excursions of about 0.5‰ at the Pliensbachian-Toarcian transition (Pl-To) and at the base of the Toarcian Oceanic Anoxic Event (T-OAE) interval. The comparison of δ44/40Ca ratios recorded in brachiopods and bulk rock corrected for variable dolomite contribution indicates that these excursions reflect changes in the global isotopic composition of seawater rather than changes in the dominant mineralogy of calcifying organisms or in hydrological budget of the considered basin. Box modeling results suggest that the Pl-To and T-OAE δ44/40Ca excursions can be explained by a transient 90% decrease of carbonate accumulation due to seawater acidification followed by a 500% increase in continental weathering rates. The sharp increases in continental weathering inferred from the δ44/40Ca ratios seem overall consistent with lower Toarcian sedimentological and biotic records that document rapid crises in carbonate production followed by episodes of increased calcium carbonate burial. Nevertheless, the maximum of carbonate burial recorded by most NW European basinal successions occurs several hundreds of kyrs after

  12. Hybrid Markov-mass action law model for cell activation by rare binding events: Application to calcium induced vesicular release at neuronal synapses

    NASA Astrophysics Data System (ADS)

    Guerrier, Claire; Holcman, David

    2016-10-01

    Binding of molecules, ions or proteins to small target sites is a generic step of cell activation. This process relies on rare stochastic events where a particle located in a large bulk has to find small and often hidden targets. We present here a hybrid discrete-continuum model that takes into account a stochastic regime governed by rare events and a continuous regime in the bulk. The rare discrete binding events are modeled by a Markov chain for the encounter of small targets by few Brownian particles, for which the arrival time is Poissonian. The large ensemble of particles is described by mass action laws. We use this novel model to predict the time distribution of vesicular release at neuronal synapses. Vesicular release is triggered by the binding of few calcium ions that can originate either from the synaptic bulk or from the entry through calcium channels. We report here that the distribution of release time is bimodal although it is triggered by a single fast action potential. While the first peak follows a stimulation, the second corresponds to the random arrival over much longer time of ions located in the synaptic terminal to small binding vesicular targets. To conclude, the present multiscale stochastic modeling approach allows studying cellular events based on integrating discrete molecular events over several time scales.

  13. Hybrid Markov-mass action law model for cell activation by rare binding events: Application to calcium induced vesicular release at neuronal synapses

    PubMed Central

    Guerrier, Claire; Holcman, David

    2016-01-01

    Binding of molecules, ions or proteins to small target sites is a generic step of cell activation. This process relies on rare stochastic events where a particle located in a large bulk has to find small and often hidden targets. We present here a hybrid discrete-continuum model that takes into account a stochastic regime governed by rare events and a continuous regime in the bulk. The rare discrete binding events are modeled by a Markov chain for the encounter of small targets by few Brownian particles, for which the arrival time is Poissonian. The large ensemble of particles is described by mass action laws. We use this novel model to predict the time distribution of vesicular release at neuronal synapses. Vesicular release is triggered by the binding of few calcium ions that can originate either from the synaptic bulk or from the entry through calcium channels. We report here that the distribution of release time is bimodal although it is triggered by a single fast action potential. While the first peak follows a stimulation, the second corresponds to the random arrival over much longer time of ions located in the synaptic terminal to small binding vesicular targets. To conclude, the present multiscale stochastic modeling approach allows studying cellular events based on integrating discrete molecular events over several time scales. PMID:27752087

  14. Hybrid Markov-mass action law model for cell activation by rare binding events: Application to calcium induced vesicular release at neuronal synapses.

    PubMed

    Guerrier, Claire; Holcman, David

    2016-10-18

    Binding of molecules, ions or proteins to small target sites is a generic step of cell activation. This process relies on rare stochastic events where a particle located in a large bulk has to find small and often hidden targets. We present here a hybrid discrete-continuum model that takes into account a stochastic regime governed by rare events and a continuous regime in the bulk. The rare discrete binding events are modeled by a Markov chain for the encounter of small targets by few Brownian particles, for which the arrival time is Poissonian. The large ensemble of particles is described by mass action laws. We use this novel model to predict the time distribution of vesicular release at neuronal synapses. Vesicular release is triggered by the binding of few calcium ions that can originate either from the synaptic bulk or from the entry through calcium channels. We report here that the distribution of release time is bimodal although it is triggered by a single fast action potential. While the first peak follows a stimulation, the second corresponds to the random arrival over much longer time of ions located in the synaptic terminal to small binding vesicular targets. To conclude, the present multiscale stochastic modeling approach allows studying cellular events based on integrating discrete molecular events over several time scales.

  15. Application of Near Infrared Spectroscopy, Intravascular Ultrasound and the Coronary Calcium Score to Predict Adverse Coronary Events

    DTIC Science & Technology

    2015-10-01

    planned. 15. SUBJECT TERMS coronary artery disease , near infrared spectroscopy, calcium scoring, intravascular ultrasound 16. SECURIY CLASSIFICATION OF...findings and intracoronary ultrasound in predicting those outcomes in #2. 6 Body Revision and review of the original protocol was followed by

  16. Review article: loss of the calcium-sensing receptor in colonic epithelium is a key event in the pathogenesis of colon cancer.

    PubMed

    Rogers, Ailín C; Hanly, Ann M; Collins, Danielle; Baird, Alan W; Winter, Desmond C

    2012-03-01

    The calcium-sensing receptor (CaSR) is expressed abundantly in normal colonic epithelium and lost in colon cancer, but its exact role on a molecular level and within the carcinogenesis pathway is yet to be described. Epidemiologic studies show that inadequate dietary calcium predisposes to colon cancer; this may be due to the ability of calcium to bind and upregulate the CaSR. Loss of CaSR expression does not seem to be an early event in carcinogenesis; indeed it is associated with late stage, poorly differentiated, chemo-resistant tumors. Induction of CaSR expression in neoplastic colonocytes arrests tumor progression and deems tumors more sensitive to chemotherapy; hence CaSR may be an important target in colon cancer treatment. The CaSR has a complex role in colon cancer; however, more investigation is required on a molecular level to clarify its exact function in carcinogenesis. This review describes the mechanisms by which the CaSR is currently implicated in colon cancer and identifies areas where further study is needed.

  17. Higher Dietary Calcium Intakes Are Associated With Reduced Risks of Fractures, Cardiovascular Events, and Mortality: A Prospective Cohort Study of Older Men and Women.

    PubMed

    Khan, Belal; Nowson, Caryl A; Daly, Robin M; English, Dallas R; Hodge, Allison M; Giles, Graham G; Ebeling, Peter R

    2015-10-01

    The aim of this population-based, prospective cohort study was to investigate long-term associations between dietary calcium intake and fractures, non-fatal cardiovascular disease (CVD), and death from all causes. Participants were from the Melbourne Collaborative Cohort Study, which was established in 1990 to 1994. A total of 41,514 men and women (∼99% aged 40 to 69 years at baseline) were followed up for a mean (SD) of 12 (1.5) years. Primary outcome measures were time to death from all causes (n = 2855), CVD-related deaths (n = 557), cerebrovascular disease-related deaths (n = 139), incident non-fatal CVD (n = 1827), incident stroke events (n = 537), and incident fractures (n = 788). A total of 12,097 participants (aged ≥50 years) were eligible for fracture analysis and 34,468 for non-fatal CVD and mortality analyses. Mortality was ascertained by record linkage to registries. Fractures and CVD were ascertained from interview ∼13 years after baseline. Quartiles of baseline energy-adjusted calcium intake from food were estimated using a food-frequency questionnaire. Hazard ratios (HR) and odds ratios (OR) were calculated for quartiles of dietary calcium intake. Highest and lowest quartiles of energy-adjusted dietary calcium intakes represented unadjusted means (SD) of 1348 (316) mg/d and 473 (91) mg/d, respectively. Overall, there were 788 (10.3%) incident fractures, 1827 (9.0%) incident CVD, and 2855 people (8.6%) died. Comparing the highest with the lowest quartile of calcium intake, for all-cause mortality, the HR was 0.86 (95% confidence interval [CI] 0.76-0.98, p(trend)  = 0.01); for non-fatal CVD and stroke, the OR was 0.84 (95% CI 0.70-0.99, p(trend)  = 0.04) and 0.69 (95% CI 0.51-0.93, p(trend)  = 0.02), respectively; and the OR for fracture was 0.70 (95% CI 0.54-0.92, p(trend)  = 0.004). In summary, for older men and women, calcium intakes of up to 1348 (316) mg/d from food were associated with decreased risks

  18. Mouse neuroblastoma cell-based model and the effect of epileptic events on calcium oscillations and neural spikes

    NASA Astrophysics Data System (ADS)

    Kim, Suhwan; Jung, Unsang; Baek, Juyoung; Lee, Sangwon; Jung, Woonggyu; Kim, Jeehyun; Kang, Shinwon

    2013-01-01

    Recently, mouse neuroblastoma cells have been considered as an attractive model for the study of human neurological and prion diseases, and they have been intensively used as a model system in different areas. For example, the differentiation of neuro2a (N2A) cells, receptor-mediated ion current, and glutamate-induced physiological responses have been actively investigated with these cells. These mouse neuroblastoma N2A cells are of interest because they grow faster than other cells of neural origin and have a number of other advantages. The calcium oscillations and neural spikes of mouse neuroblastoma N2A cells in epileptic conditions are evaluated. Based on our observations of neural spikes in these cells with our proposed imaging modality, we reported that they can be an important model in epileptic activity studies. We concluded that mouse neuroblastoma N2A cells produce epileptic spikes in vitro in the same way as those produced by neurons or astrocytes. This evidence suggests that increased levels of neurotransmitter release due to the enhancement of free calcium from 4-aminopyridine causes the mouse neuroblastoma N2A cells to produce epileptic spikes and calcium oscillations.

  19. Mouse neuroblastoma cell based model and the effect of epileptic events on calcium oscillations and neural spikes

    NASA Astrophysics Data System (ADS)

    Kim, Suhwan; Baek, Juyeong; Jung, Unsang; Lee, Sangwon; Jung, Woonggyu; Kim, Jeehyun; Kang, Shinwon

    2013-05-01

    Recently, Mouse neuroblastoma cells are considered as an attractive model for the study of human neurological and prion diseases, and intensively used as a model system in different areas. Among those areas, differentiation of neuro2a (N2A) cells, receptor mediated ion current, and glutamate induced physiological response are actively investigated. The reason for the interest to mouse neuroblastoma N2A cells is that they have a fast growing rate than other cells in neural origin with a few another advantages. This study evaluated the calcium oscillations and neural spikes recording of mouse neuroblastoma N2A cells in an epileptic condition. Based on our observation of neural spikes in mouse N2A cell with our proposed imaging modality, we report that mouse neuroblastoma N2A cells can be an important model related to epileptic activity studies. It is concluded that the mouse neuroblastoma N2A cells produce the epileptic spikes in vitro in the same way as produced by the neurons or the astrocytes. This evidence advocates the increased and strong level of neurotransmitters release by enhancement in free calcium using the 4-aminopyridine which causes the mouse neuroblastoma N2A cells to produce the epileptic spikes and calcium oscillation.

  20. [Psychosocial stress preceding drug-related deaths].

    PubMed

    Kraus, L; Müller-Kalthoff, T

    2002-10-01

    This article analyses drug-related deaths in the German Federal States of Bavaria (Munich, Nuremberg and Augsburg counties) during 1999 and Baden-Wurttemberg (Stuttgart and Mannheim counties) during 1999 and in the first half of 2000. The persons who had been in contact with drug care services were studied for psychosocial stress preceding drug-related deaths. Epidemiological data from different sources (police, relatives, counselling centres, detoxification clinics, therapy and substitution treatment) were collated to estimate factors of psychosocial stress preceding drug deaths. The results in both Laender indicate high prevalence rates of a history of at least one non-fatal overdose (approx. 50%) or a suicide attempt (approx. 35%). More than 40% of the deceased had been suffering from at least one additional mental disorder, in most cases from depression. At least one critical life event (in most cases, a relapse) or a period of abstinence (i.e., due to imprisonment, therapy or detoxification) during the past three months before death was reported for more than half of the addicts. The results were discussed in the light of data on opiate users and the general population. Improved specialist training of therapeutic and medical workers as well as of any other co-operating professionals is considered a necessary prerequisite for an early detection of risk factors.

  1. Calcium handling precedes cardiac differentiation to initiate the first heartbeat

    PubMed Central

    Tyser, Richard CV; Miranda, Antonio MA; Chen, Chiann-mun; Davidson, Sean M

    2016-01-01

    The mammalian heartbeat is thought to begin just prior to the linear heart tube stage of development. How the initial contractions are established and the downstream consequences of the earliest contractile function on cardiac differentiation and morphogenesis have not been described. Using high-resolution live imaging of mouse embryos, we observed randomly distributed spontaneous asynchronous Ca2+-oscillations (SACOs) in the forming cardiac crescent (stage E7.75) prior to overt beating. Nascent contraction initiated at around E8.0 and was associated with sarcomeric assembly and rapid Ca2+ transients, underpinned by sequential expression of the Na+-Ca2+ exchanger (NCX1) and L-type Ca2+ channel (LTCC). Pharmacological inhibition of NCX1 and LTCC revealed rapid development of Ca2+ handling in the early heart and an essential early role for NCX1 in establishing SACOs through to the initiation of beating. NCX1 blockade impacted on CaMKII signalling to down-regulate cardiac gene expression, leading to impaired differentiation and failed crescent maturation. DOI: http://dx.doi.org/10.7554/eLife.17113.001 PMID:27725084

  2. H3K9 trimethylation precedes DNA methylation during sheep oogenesis: HDAC1, SUV39H1, G9a, HP1, and Dnmts are involved in these epigenetic events.

    PubMed

    Russo, Valentina; Bernabò, Nicola; Di Giacinto, Oriana; Martelli, Alessandra; Mauro, Annunziata; Berardinelli, Paolo; Curini, Valentina; Nardinocchi, Delia; Mattioli, Mauro; Barboni, Barbara

    2013-01-01

    The oocyte, to become a fully mature gamete, has to acquire a correct pattern of DNA methylation on its genome; this epigenetic event represents the major point of the molecular mechanisms that occur during postnatal oogenesis. It is known that an intimate link exists between DNA methylation and histone posttranslational modifications, such as trimethylation of lysine 9 on histone 3 (H3K9me3), that is essential in the silencing of gene transcription. What remains unclear is the precise sequence of these two epigenetic events and the protein expression of the enzymes that catalyze this epigenetic maturation during oogenesis. To identify the key molecules involved in global DNA methylation and H3K9me3, a biological network-based computational model was realized. Then, the spatiotemporal distribution of the proteins, identified from the biological network, was assessed during postnatal oogenesis. The results obtained suggest the existence of a sequential cascade of events in which H3K9me3 is the primary step followed by DNA methylation. These two epigenetic marks are realized due to the recruitment of the HDAC1, SUV39H1, G9a, HP1, and Dnmt3a, which were always localized in the nuclei of the oocytes and were dependent on chromatin configuration. These results involving DNA methylation and H3K9me3 are crucial in defining the oocyte developmental competence.

  3. 47 CFR 213.5 - Precedence designators.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 47 Telecommunication 5 2010-10-01 2010-10-01 false Precedence designators. 213.5 Section 213.5 Telecommunication OFFICE OF SCIENCE AND TECHNOLOGY POLICY AND NATIONAL SECURITY COUNCIL GOVERNMENT AND PUBLIC CORRESPONDENCE TELECOMMUNICATIONS PRECEDENCE SYSTEM § 213.5 Precedence designators. (a) The following...

  4. 47 CFR 213.5 - Precedence designators.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 47 Telecommunication 5 2014-10-01 2014-10-01 false Precedence designators. 213.5 Section 213.5 Telecommunication OFFICE OF SCIENCE AND TECHNOLOGY POLICY AND NATIONAL SECURITY COUNCIL GOVERNMENT AND PUBLIC CORRESPONDENCE TELECOMMUNICATIONS PRECEDENCE SYSTEM § 213.5 Precedence designators. (a) The following...

  5. 47 CFR 213.5 - Precedence designators.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 47 Telecommunication 5 2012-10-01 2012-10-01 false Precedence designators. 213.5 Section 213.5 Telecommunication OFFICE OF SCIENCE AND TECHNOLOGY POLICY AND NATIONAL SECURITY COUNCIL GOVERNMENT AND PUBLIC CORRESPONDENCE TELECOMMUNICATIONS PRECEDENCE SYSTEM § 213.5 Precedence designators. (a) The following...

  6. 47 CFR 213.5 - Precedence designators.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 47 Telecommunication 5 2013-10-01 2013-10-01 false Precedence designators. 213.5 Section 213.5 Telecommunication OFFICE OF SCIENCE AND TECHNOLOGY POLICY AND NATIONAL SECURITY COUNCIL GOVERNMENT AND PUBLIC CORRESPONDENCE TELECOMMUNICATIONS PRECEDENCE SYSTEM § 213.5 Precedence designators. (a) The following...

  7. 47 CFR 213.5 - Precedence designators.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 47 Telecommunication 5 2011-10-01 2011-10-01 false Precedence designators. 213.5 Section 213.5 Telecommunication OFFICE OF SCIENCE AND TECHNOLOGY POLICY AND NATIONAL SECURITY COUNCIL GOVERNMENT AND PUBLIC CORRESPONDENCE TELECOMMUNICATIONS PRECEDENCE SYSTEM § 213.5 Precedence designators. (a) The following...

  8. Submicroscopic calcium signals as fundamental events of excitation--contraction coupling in guinea-pig cardiac myocytes.

    PubMed Central

    Lipp, P; Niggli, E

    1996-01-01

    1. Subcellularly localized Ca2+ signals have been proposed to represent elementary events of cardiac Ca2+ signalling (Ca2+ sparks), whereby an individual sarcolemmal L-type Ca2+ channel locally controls opening of a single (or a few) Ca2+ release channels in the sarcoplasmic reticulum (SR). 2. To investigate directly the elementary nature of this Ca(2+)-induced Ca2+ release mechanism we used flash photolysis of caged Ca2+ while simultaneously measuring the intracellular Ca2+ concentration ([Ca2+]i) with a laser-scanning confocal microscope. 3. Power spectral analysis of the confocal images performed in the spatial domain revealed that only Ca2+ signalling events involving the L-type Ca2+ channel pathway gave rise to Ca2+ sparks. In contrast, SR Ca2+ release triggered by photolytic [Ca2+]i jumps resulted in Ca2+ transients that were always spatially homogeneous. 4. From these findings we conclude that the fundamental event of Ca2+ signalling in cardiac muscle may be smaller in size or amplitude than a Ca2+ spark. 5. We term this event a 'Ca2+ quark' possibly resulting from gating of a single SR Ca2+ release channel. It is proposed that concerted activation of several 'Ca2+ quarks' may be required for a Ca2+ spark. The 'Ca2+ quark' could also be the fundamental event in other cell types implementing a hierarchical Ca2+ signalling concept. Images Fig. 1 Figure 2 (cont.) Figure 2 Figure 3 PMID:8730580

  9. Precedence relationship representations of mechanical assembly sequences

    NASA Technical Reports Server (NTRS)

    Homendemello, L. S.; Sanderson, A. C.

    1989-01-01

    Two types of precedence relationship representations for mechanical assembly sequences are presented: precedence relationships between the establishment of one connection between two parts and the establishment of another connection, and precedence relationships between the establishment of one connection and states of the assembly process. Precedence relationship representations have the advantage of being very compact. The problem with these representations was how to guarantee their correctness and completeness. Two theorems are presented each of which leads to the generation of one type of precedence relationship representation guaranteeing its correctness and completeness for a class of assemblies.

  10. Combination effect of calcium channel blocker and valsartan on cardiovascular event prevention in patients with high-risk hypertension: ancillary results of the KYOTO HEART Study.

    PubMed

    Sawada, Takahisa; Yamada, Hiroyuki; Shiraishi, Jun; Kimura, Shinzo; Matsubara, Hiroaki

    2012-01-01

    The ancillary analysis of the KYOTO HEART Study (n = 3031) was designed to assess the combined treatment with calcium channel blocker (CCB) plus valsartan for high-risk hypertension. With-CCB (n = 1807) showed less primary events than without-CCB (n = 1224) (P = .037), in which acute myocardial infarction was significantly reduced. With-CCB plus valsartan (n = 773) showed lower incidence than with-CCB plus non-angiotensin receptor blocker (ARB) (n = 1034) (P = .0002), in which angina pectoris and heart failure were significantly reduced. Without-CCB plus valsartan (n = 744) was superior to without-CCB plus non-ARB (n = 480) (P = .0013), in which stroke was reduced. CCB-based therapy was useful, and CCB plus valsartan combination provided a more efficient prevention for high-risk hypertensive patients.

  11. Calcium supplements

    MedlinePlus

    ... TYPES OF CALCIUM SUPPLEMENTS Forms of calcium include: Calcium carbonate: Over-the-counter (OTC) antacid products, such as Tums and Rolaids, contain calcium carbonate. These sources of calcium do not cost much. ...

  12. The effects of a whole-watershed calcium addition on the chemistry of stream storm events at the Hubbard Brook Experimental Forest in NH, USA.

    PubMed

    Cho, Youngil; Driscoll, Charles T; Blum, Joel D

    2009-10-01

    Patterns of storm runoff chemistry from a wollastonite (calcium-silicate mineral, CaSiO(3)) treated watershed (W1) were compared with a reference watershed (W6) at the Hubbard Brook Experimental Forest (HBEF) in New Hampshire (NH), USA to investigate the role of Ca(2+) supply in the acid-base status of stream chemistry. In the summer of 2003, six storm events were studied in W1 and W6 to evaluate the effects of the wollastonite treatment on the episodic acidification of stream waters. Although mean values of Ca(2+) concentrations decreased slightly from 33.8 to 31.7 mumol/L with increasing stream discharge in W1 during the events, the mean value of acid neutralizing capacity (ANC) was positive (1.2 mueq/L) during storm events, compared to negative values (-0.2 mueq/L) in W6. This pattern is presumably due to enhanced Ca(2+) supply in W1 (20.7 to 29.0% of dissolved Ca(2+) derived from the added wollastonite) to stream water as a result of interflow along shallow flowpaths. In addition, the application of wollastonite increased pH and dissolved silica (H(4)SiO(4)) concentrations, and decreased the concentration of inorganic monomeric Al (Al(i)) in W1 in comparison with W6 during storm events. Despite an increase in SO(4)(2-) concentration, likely due to desorption of sulfate from soil after the treatment, the watershed showed an increase in ANC compared to the reference watershed, serving to mitigate episodic acidification.

  13. What precedes development of rheumatoid arthritis?

    PubMed Central

    Klareskog, L; Alfredsson, L; Rantapaa-Dahlqvis..., S; Berglin, E; Stolt, P; Padyukov, L

    2004-01-01

    Studies on aetiology of inflammatory diseases such as rheumatoid arthritis (RA) need to investigate the potential environmental triggers that are active before onset of disease, the genetic context in which these triggers act, and whether the presence of such triggers in an arthritis prone genetic context will give rise to the immune reactions associated with/preceding RA. Such knowledge would help not only to address much better the issue of causality of these potential triggers and the immune reactions, but also to carry out various interventions aimed at influencing the disease provoking immune events before development of clinical signs of disease. This short report summarises recent data demonstrating (a) the presence of anticitrullin antibodies or rheumatoid factors in between a third and half of patients with RA before development of clinical signs; (b) long term smoking is associated with a high risk of future development of seropositive but not seronegative RA; and (c) a strong gene–environment interaction between smoking and SE genes in the development of seropositive RA. We conclude that, in a certain genetic context, smoking is a potential trigger of RA, and a combination of the two factors is associated with the occurrence of immune reactions long before the onset of RA. PMID:15479868

  14. Listeria monocytogenes meningitis preceded by acute cholangitis.

    PubMed

    Luthe, Sarah Kyuragi; Sato, Ryota; Maeda, Tetsuro; Takahashi, Kuniko

    2017-03-20

    Listeria monocytogenes is a well-known cause of meningitis in immunocompromised patients. This organism has a growing significance for community-acquired meningitis, which should have ampicillin added to the usual regimen. We describe a case of L. monocytogenes meningitis preceded by cholangitis. This case suggests gastrointestinal symptoms preceding meningitis may be a clue of listeriosis. It is important for physicians to consider L. monocytogenes as a cause of bacterial meningitis in patients with altered mental status preceded by gastrointestinal symptoms, especially in the immunocompromised population.

  15. Motility precedes egress of malaria parasites from oocysts

    PubMed Central

    Klug, Dennis; Frischknecht, Friedrich

    2017-01-01

    Malaria is transmitted when an infected Anopheles mosquito deposits Plasmodium sporozoites in the skin during a bite. Sporozoites are formed within oocysts at the mosquito midgut wall and are released into the hemolymph, from where they invade the salivary glands and are subsequently transmitted to the vertebrate host. We found that a thrombospondin-repeat containing sporozoite-specific protein named thrombospondin-releated protein 1 (TRP1) is important for oocyst egress and salivary gland invasion, and hence for the transmission of malaria. We imaged the release of sporozoites from oocysts in situ, which was preceded by active motility. Parasites lacking TRP1 failed to migrate within oocysts and did not egress, suggesting that TRP1 is a vital component of the events that precede intra-oocyst motility and subsequently sporozoite egress and salivary gland invasion. DOI: http://dx.doi.org/10.7554/eLife.19157.001 PMID:28115054

  16. A solution NMR investigation into the early events of amelogenin nanosphere self-assembly initiated with sodium chloride or calcium chloride.

    PubMed

    Buchko, Garry W; Tarasevich, Barbara J; Bekhazi, Jacky; Snead, Malcolm L; Shaw, Wendy J

    2008-12-16

    Using solution-state NMR spectroscopy, new insights into the early events governing amelogenin supramolecular self-assembly have been identified using sodium chloride and calcium chloride to trigger the association. Two-dimensional 1H-15N HSQC spectra were recorded for 15N- and 13C-labeled murine amelogenin as a function of increasing NaCl and CaCl2 concentration beginning with solution conditions of 2% acetic acid at pH 3.0, where amelogenin was monomeric. Residue specific changes in molecular dynamics, manifested by the reduction in intensity and disappearance of 1H-15N HSQC cross-peaks, were observed with the addition of either salt to the protein. With increasing NaCl concentrations, residues between T21 and R31 near the N-terminus were affected first, suggesting that these residues may initiate amelogenin dimerization, the first step in nanosphere assembly. At higher NaCl concentrations, more residues near the N-terminus (Y12-I51) were affected, and with further additions of NaCl, residues near the C-terminus (L141-T171) began to show a similar change in molecular dynamics. With increasing CaCl2 concentrations, a similar stepwise change in molecular dynamics involving essentially the same set of amelogenin residues was observed. As the concentration of either salt was increased, a concomitant increase in the estimated overall rotational correlation time (tau(c)) was observed, consistent with assembly. Self-assembly into a dimer or trimer was established with dynamic light scattering studies under similar conditions that showed an increase in diameter of the smallest species from 4.1 nm in the absence of salt to 10 nm in the presence of salt. These results suggest a possible stepwise interaction mechanism, starting with the N-terminus and followed by the C-terminus, leading to amelogenin nanosphere assembly.

  17. Thrombotic thrombocytopenic purpura preceding systemic lupus erythematosus.

    PubMed Central

    Simeon-Aznar, C P; Cuenca-Luque, R; Fonollosa-Pla, V; Bosch-Gil, J A

    1992-01-01

    The case of a patient admitted with thrombotic thrombocytopenic purpura nine years after developing systemic lupus erythematosus (SLE) is reported. Thrombotic thrombocytopenic purpura associated with SLE has been described on other occasions, but in most patients the diagnosis of SLE precedes that of thrombotic thrombocytopenic purpura. The unusual sequence and the chronological separation of the two diseases is emphasised. PMID:1575591

  18. On the Rhetoric and Precedents of Racism.

    ERIC Educational Resources Information Center

    Villanueva, Victor

    1999-01-01

    Considers contribution of rhetorical training of the Aztecs prior to the European conquest as well as other early philosophers from the Americas. Encourages breaking precedent in order to battle racism by looking to rhetorical training developed in the Americas and Puerto Rico in addition to the European thinkers. (SC)

  19. Sleep Disturbance Preceding Completed Suicide in Adolescents

    ERIC Educational Resources Information Center

    Goldstein, Tina R.; Bridge, Jeffrey A.; Brent, David A.

    2008-01-01

    We examined sleep difficulties preceding death in a sample of adolescent suicide completers as compared with a matched sample of community control adolescents. Sleep disturbances were assessed in 140 adolescent suicide victims with a psychological autopsy protocol and in 131 controls with a similar semistructured psychiatric interview. Rates of…

  20. More Than the Rules of Precedence

    ERIC Educational Resources Information Center

    Liang, Yawei

    2005-01-01

    In a fundamental computer-programming course, such as CSE101, questions about how to evaluate an arithmetic expression are frequently used to check if our students know the rules of precedence. The author uses two of our final examination questions to show that more knowledge of computer science is needed to answer them correctly. Furthermore,…

  1. Generation of precedence relations for mechanical assemblies

    NASA Technical Reports Server (NTRS)

    Zhang, Hui; Sanderson, A. C.

    1989-01-01

    Planning of assembly sequences is essential to the manufacturing system design process. Several methodologies have been proposed to represent all the feasible assembly sequences. In this thesis, three algorithms are presented to generate three sets of precedence relations based on all the infeasible assembly tasks, all the infeasible assembly states, and all the feasible assembly sequences, respectively. The equivalence of the resulting sets of precedence relations to the AND/OR graph is established. A new property, the real time property, of a representation of assembly sequences is defined and discussed. A representation of assembly sequences is said to have the real time property, if it is possible to generate the next assembly task by testing locally in the representation, and it will guarantee that the generated assembly task will not lead the assembly sequence to a dead end situation, in which no feasible assembly task can be performed any more. It is shown that the correctness and completeness of one representation can not guarantee the real time property of the representation. It is proven that the directed graph representation and the set of precedence relations based on all the infeasible assembly states have the real time property, while the AND/OR graph representation and the set of precedence relations based on all the infeasible assembly tasks do not have the real time property. Finally in the thesis, the PLEIDEAS system, a PLanning Environment for Integrated DEsign of Assembly Systems, is described and illustrated by an example.

  2. 32 CFR 700.501 - Precedence.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... OFFICIAL RECORDS UNITED STATES NAVY REGULATIONS AND OFFICIAL RECORDS The Commandant of the Marine Corps § 700.501 Precedence. The Commandant of the Marine Corps, while so serving, has the grade of general. In the performance of duties within the Department of the Navy, the Commandant of the Marine Corps...

  3. Systems Biology Approach Reveals a Calcium-Dependent Mechanism for Basal Toxicity in Daphnia magna.

    PubMed

    Antczak, Philipp; White, Thomas A; Giri, Anirudha; Michelangeli, Francesco; Viant, Mark R; Cronin, Mark T D; Vulpe, Chris; Falciani, Francesco

    2015-09-15

    The expanding diversity and ever increasing amounts of man-made chemicals discharged to the environment pose largely unknown hazards to ecosystem and human health. The concept of adverse outcome pathways (AOPs) emerged as a comprehensive framework for risk assessment. However, the limited mechanistic information available for most chemicals and a lack of biological pathway annotation in many species represent significant challenges to effective implementation of this approach. Here, a systems level, multistep modeling strategy demonstrates how to integrate information on chemical structure with mechanistic insight from genomic studies, and phenotypic effects to define a putative adverse outcome pathway. Results indicated that transcriptional changes indicative of intracellular calcium mobilization were significantly overrepresented in Daphnia magna (DM) exposed to sublethal doses of presumed narcotic chemicals with log Kow ≥ 1.8. Treatment of DM with a calcium ATPase pump inhibitor substantially recapitulated the common transcriptional changes. We hypothesize that calcium mobilization is a potential key molecular initiating event in DM basal (narcosis) toxicity. Heart beat rate analysis and metabolome analysis indicated sublethal effects consistent with perturbations of calcium preceding overt acute toxicity. Together, the results indicate that altered calcium homeostasis may be a key early event in basal toxicity or narcosis induced by lipophilic compounds.

  4. Calcium in plant defence-signalling pathways.

    PubMed

    Lecourieux, David; Ranjeva, Raoul; Pugin, Alain

    2006-01-01

    In plant cells, the calcium ion is a ubiquitous intracellular second messenger involved in numerous signalling pathways. Variations in the cytosolic concentration of Ca2+ ([Ca2+]cyt) couple a large array of signals and responses. Here we concentrate on calcium signalling in plant defence responses, particularly on the generation of the calcium signal and downstream calcium-dependent events participating in the establishment of defence responses with special reference to calcium-binding proteins.

  5. Metabolomic change precedes apple superficial scald symptoms.

    PubMed

    Rudell, David R; Mattheis, James P; Hertog, Maarten L A T M

    2009-09-23

    Untargeted metabolic profiling was employed to characterize metabolomic changes associated with 'Granny Smith' apple superficial scald development following 1-MCP or DPA treatment. Partial least-squares discriminant analyses were used to link metabolites with scald, postharvest treatments, and storage duration. Models revealed metabolomic differentiation between untreated controls and fruit treated with DPA or 1-MCP within 1 week following storage initiation. Metabolic divergence between controls and DPA-treated fruit after 4 weeks of storage preceded scald symptom development by 2 months. alpha-Farnesene oxidation products with known associations to scald, including conjugated trienols, 6-methyl-5-hepten-2-one, and 6-methyl-5-hepten-2-ol, were associated with presymptomatic as well as scalded control fruit. Likewise, a large group of putative triterpenoids with mass spectral features similar to those of ursolic acid and beta-sitosterol were associated with control fruit and scald. Results demonstrate that extensive metabolomic changes associated with scald precede actual symptom development.

  6. An angiotensin II receptor blocker-calcium channel blocker combination prevents cardiovascular events in elderly high-risk hypertensive patients with chronic kidney disease better than high-dose angiotensin II receptor blockade alone.

    PubMed

    Kim-Mitsuyama, Shokei; Ogawa, Hisao; Matsui, Kunihiko; Jinnouchi, Tomio; Jinnouchi, Hideaki; Arakawa, Kikuo

    2013-01-01

    The OSCAR study was a multicenter, prospective randomized open-label blinded end-point study of 1164 Japanese elderly hypertensive patients comparing the efficacy of angiotensin II receptor blocker (ARB) uptitration to an ARB plus calcium channel blocker (CCB) combination. In this prospective study, we performed prespecified subgroup analysis according to baseline estimated glomerular filtration rate (eGFR) with chronic kidney disease (CKD) defined as an eGFR <60 ml/min per 1.73 m(2). Blood pressure was lower in the combined therapy than in the high-dose ARB cohort in both groups with and without CKD. In patients with CKD, significantly more primary events (a composite of cardiovascular events and noncardiovascular death) occurred in the high-dose ARB group than in the combination group (30 vs. 16, respectively, hazard ratio 2.25). Significantly more cerebrovascular and more heart failure events occurred in the high-dose ARB group than in the combination group. In patients without CKD, however, the incidence of primary events was similar between the two treatments. The treatment-by-subgroup interaction was significant. Allocation to the high-dose ARB was a significant independent prognostic factor for primary events in patients with CKD. Thus, the ARB plus CCB combination conferred greater benefit in prevention of cardiovascular events in patients with CKD compared with high-dose ARB alone. Our findings provide new insight into the antihypertensive strategy for elderly hypertensive patients with CKD.

  7. Incremental prognostic value of coronary computed tomographic angiography over coronary artery calcium score for risk prediction of major adverse cardiac events in asymptomatic diabetic individuals

    PubMed Central

    Min, James K.; Labounty, Troy M.; Gomez, Millie J.; Achenbach, Stephan; Al-Mallah, Mouaz; Budoff, Matthew J.; Cademartiri, Filippo; Callister, Tracy Q.; Chang, Hyuk-Jae; Cheng, Victor; Chinnaiyan, Kavitha M.; Chow, Benjamin; Cury, Ricardo; Delago, Augustin; Dunning, Allison; Feuchtner, Gudrun; Hadamitzky, Martin; Hausleiter, Jorg; Kaufmann, Philipp; Kim, Yong-Jin; Leipsic, Jonathon; Lin, Fay Y.; Maffei, Erica; Raff, Gilbert; Shaw, Leslee J.; Villines, Todd C.; Berman, Daniel S.

    2015-01-01

    Background Coronary artery disease (CAD) diagnosis by coronary computed tomographic angiography (CCTA) is useful for identification of symptomatic diabetic individuals at heightened risk for death. Whether CCTA-detected CAD enables improved risk assessment of asymptomatic diabetic individuals beyond clinical risk factors and coronary artery calcium scoring (CACS) remains unexplored. Methods From a prospective 12-center international registry of 27,125 individuals undergoing CCTA, we identified 400 asymptomatic diabetic individuals without known CAD. Coronary stenosis by CCTA was graded as 0%, 1–49%, 50–69%, and ≥70%. CAD was judged on a per-patient, per-vessel and per-segment basis as maximal stenosis severity, number of vessels with ≥50% stenosis, and coronary segments weighted for stenosis severity (segment stenosis score), respectively. We assessed major adverse cardiovascular events (MACE) – inclusive of mortality, nonfatal myocardial infarction (MI), and late target vessel revascularization ≥90 days (REV) – and evaluated the incremental utility of CCTA for risk prediction, discrimination and reclassification. Results Mean age was 60.4 ± 9.9 years; 65.0% were male. At a mean follow-up 2.4 ± 1.1 years, 33 MACE occurred (13 deaths, 8 MI, 12 REV) [8.25%; annualized rate 3.4%]. By univariate analysis, per-patient maximal stenosis [hazards ratio (HR) 2.24 per stenosis grade, 95% confidence interval (CI) 1.61–3.10, p < 0.001], increasing numbers of obstructive vessels (HR 2.30 per vessel, 95% CI 1.75–3.03, p < 0.001) and segment stenosis score (HR 1.14 per segment, 95% CI 1.09–1.19, p < 0.001) were associated with increased MACE. After adjustment for CAD risk factors and CACS, maximal stenosis (HR 1.80 per grade, 95% CI 1.18–2.75, p = 0.006), number of obstructive vessels (HR 1.85 per vessel, 95% CI 1.29–2.65, p < 0.001) and segment stenosis score (HR 1.11 per segment, 95% CI 1.05–1.18, p < 0.001) were associated with increased risk of

  8. Cutaneous presentation preceding acute monocytic leukemia

    PubMed Central

    Jin, Xianhua; Li, Fuqiu; Li, Xue; Zhu, Wenjing; Mou, Yan; Huang, Yang; Zhao, Huanyu; Gao, Wei; Xia, Jianxin

    2017-01-01

    Abstract Rationale: Cutaneous presentation preceding acute myeloid leukemia (AML) is rare, and the prognosis is poor. Patient concerns: We report 4 cases of AML cutis, where skin infiltration precedes any blood or bone marrow evidence of leukemia. We also reviewed 13 cases reported in English and Chinese literature. The 4 cases all presented typical cutaneous lesions without any systemic evidence of leukemia. Histopathological examination found that dense monomorphous cell infiltration involved the dermis. Some cells surrounded blood vessels and skin appendages in a concentric manner or showed single-row arrangement in the collagen fiber bundles. Uninvolved papillary dermis was found to separate normal epidermis from dermal infiltration. Minor cells had a large kidney-shaped or oval nucleus with nucleoli and slightly eosinophilic cytoplasm. Immunohistochemical analysis was positive for CD4, CD56, while CD123 was negative in all cases. Diagnoses: AML-M5. Interventions: 2 patients received chemotherapy ,but others rejected treatment. Outcomes: Most patients died within 1 year after the onset of skin lesions. Lessons: These findings suggest that skin infiltration of AML may precede any systemic evidence, and typical cutaneous lesions in elderly individuals may be indicative for AML. PMID:28272239

  9. Effect of preceding medications on resuscitation outcome of out-of-hospital cardiac arrest

    PubMed Central

    Hung, Shih-Wen; Chu, Chien-Ming; Su, Chih-Feng; Tseng, Li-Ming; Wang, Tzong-Luen

    2017-01-01

    As evidence regarding the impact of preceding medications on resuscitation outcomes has been inconsistent, this study aimed to analyze the association between preceding medications and resuscitation outcomes in patients experiencing out-of-hospital cardiac arrest (OHCA). This retrospective study included patients with OHCA presenting to a tertiary care hospital by emergency medical service (EMS) between January 2006 and June 2011. Using the Utstein template, data were collected from EMS and hospital medical records for prehospital care, in-hospital care, and medications which were taken continuously for at least 2 weeks preceding OHCA. Primary outcome was the proportion of patients with a survived event. Multivariable logistic regression analyses were performed to evaluate the predictors of survived events. Among the 1381 included patients with OHCA, 552 (40.0%) patients achieved sustained return of spontaneous circulation and 463 (33.5%) patients survived after resuscitation, 96 (7.0%) patients survived until discharge, and 20 (1.4%) patients had a favorable neurological outcome at discharge. The multivariable analyses revealed that use of statins preceding OHCA was independently associated with a greater probability of a survived events (OR=2.09, 95% CI 1.08 to 4.03, p=0.028).Use of digoxin was adversely associated with survived events (OR=0.39, 95% CI 0.16 to 0.90, p=0.028) in patients with OHCA. The continuous use of statins preceding OHCA was positively associated with survived events, while use of digoxin was adversely related. It deserves more attention on medications preceding OHCA because of their potential effect on resuscitation outcomes. PMID:27965361

  10. Calcium - urine

    MedlinePlus

    ... into the urine, which causes calcium kidney stones Sarcoidosis Taking too much calcium Too much production of ... Milk-alkali syndrome Proximal renal tubular acidosis Rickets Sarcoidosis Vitamin D Review Date 5/3/2015 Updated ...

  11. Whole-Organ analysis of calcium behaviour in the developing pistil of olive (Olea europaea L.) as a tool for the determination of key events in sexual plant reproduction

    PubMed Central

    2011-01-01

    Background The pistil is a place where multiple interactions between cells of different types, origin, and function occur. Ca2+ is one of the key signal molecules in plants and animals. Despite the numerous studies on Ca2+ signalling during pollen-pistil interactions, which constitute one of the main topics of plant physiology, studies on Ca2+ dynamics in the pistil during flower formation are scarce. The purpose of this study was to analyze the contents and in situ localization of Ca2+ at the whole-organ level in the pistil of olive during the whole course of flower development. Results The obtained results showed significant changes in Ca2+ levels and distribution during olive pistil development. In the flower buds, the lowest levels of detectable Ca2+ were observed. As flower development proceeded, the Ca2+ amount in the pistil successively increased and reached the highest levels just after anther dehiscence. When the anthers and petals fell down a dramatic but not complete drop in calcium contents occurred in all pistil parts. In situ Ca2+ localization showed a gradual accumulation on the stigma, and further expansion toward the style and the ovary after anther dehiscence. At the post-anthesis phase, the Ca2+ signal on the stigmatic surface decreased, but in the ovary a specific accumulation of calcium was observed only in one of the four ovules. Ultrastructural localization confirmed the presence of Ca2+ in the intracellular matrix and in the exudate secreted by stigmatic papillae. Conclusions This is the first report to analyze calcium in the olive pistil during its development. According to our results in situ calcium localization by Fluo-3 AM injection is an effective tool to follow the pistil maturity degree and the spatial organization of calcium-dependent events of sexual reproduction occurring in developing pistil of angiosperms. The progressive increase of the Ca2+ pool during olive pistil development shown by us reflects the degree of pistil maturity

  12. Hydroclimatic conditions preceding the March 2014 Oso landslide

    USGS Publications Warehouse

    Henn, Brian; Cao, Qian; Lettenmaier, Dennis P.; Magirl, Christopher S.; Mass, Clifford; Bower, J. Brent; St. Laurent, Michael; Mao, Yixin; Perica, Sanja

    2015-01-01

    The 22 March 2014 Oso landslide was one of the deadliest in U.S. history, resulting in 43 fatalities and the destruction of more than 40 structures. We examine synoptic conditions, precipitation records and soil moisture reconstructions in the days, months, and years preceding the landslide. Atmospheric reanalysis shows a period of enhanced moisture transport to the Pacific Northwest beginning on 11 February 2014. The 21- to 42-day periods prior to the landslide had anomalously high precipitation; we estimate that 300-400 mm of precipitation fell at Oso in the 21 days prior to the landslide. Relative only to historical periods ending on 22 March, the return periods of these precipitation accumulations are large (25-88 years). However, relative to the largest accumulations from any time of the year (annual maxima), return periods are more modest (2-6 years). In addition to the 21-42 days prior to the landslide, there is a secondary maximum in the precipitation return periods for the 4 years preceding the landslide. Reconstructed soil moisture was anomalously high prior to the landslide, with a return period that exceeded 40 years about a week before the event.

  13. Cellular contraction precedes membrane depolarization in Vorticella convallaria

    PubMed

    Shiono; Naitoh

    1997-01-01

    Application of a mechanical stimulus to the cell body of the peritrich ciliate Vorticella convallaria evoked an all-or-nothing membrane depolarization, the large pulse. This was always accompanied by an all-or-nothing cellular contraction, and simultaneous recordings of the two events revealed that the large pulse was always preceded by the cellular contraction. A smaller graded membrane depolarization (the medium pulse) was sometimes produced in response to a weaker mechanical stimulus. The medium pulse was accompanied by a small, graded, localized contraction of the cell body and was occasionally followed by a large pulse. When a large pulse occurred during a medium pulse, it reached the same peak level as that of a large pulse evoked without a preceding medium pulse. When a medium pulse occurred during a medium pulse, summation of the two pulses was observed. Sustained contraction causes V. convallaria to become rounded, and in this state a mechanical stimulus stronger than that used to evoke the large pulse evoked a graded depolarizing mechanoreceptor potential in the cell. We conclude that both the large and medium pulses are caused by an inward receptor current that is activated mechanically following contraction of the cell body. A localized contraction evokes a small mechanoreceptor current, causing a medium pulse. An all-or-nothing contraction evokes a saturated, all-or-nothing mechanoreceptor current, causing a large pulse.

  14. Continental warming preceding the Palaeocene-Eocene thermal maximum.

    PubMed

    Secord, Ross; Gingerich, Philip D; Lohmann, Kyger C; Macleod, Kenneth G

    2010-10-21

    Marine and continental records show an abrupt negative shift in carbon isotope values at ∼55.8 Myr ago. This carbon isotope excursion (CIE) is consistent with the release of a massive amount of isotopically light carbon into the atmosphere and was associated with a dramatic rise in global temperatures termed the Palaeocene-Eocene thermal maximum (PETM). Greenhouse gases released during the CIE, probably including methane, have often been considered the main cause of PETM warming. However, some evidence from the marine record suggests that warming directly preceded the CIE, raising the possibility that the CIE and PETM may have been linked to earlier warming with different origins. Yet pre-CIE warming is still uncertain. Disentangling the sequence of events before and during the CIE and PETM is important for understanding the causes of, and Earth system responses to, abrupt climate change. Here we show that continental warming of about 5 °C preceded the CIE in the Bighorn Basin, Wyoming. Our evidence, based on oxygen isotopes in mammal teeth (which reflect temperature-sensitive fractionation processes) and other proxies, reveals a marked temperature increase directly below the CIE, and again in the CIE. Pre-CIE warming is also supported by a negative amplification of δ(13)C values in soil carbonates below the CIE. Our results suggest that at least two sources of warming-the earlier of which is unlikely to have been methane-contributed to the PETM.

  15. Symptoms of schizotypy precede cannabis use.

    PubMed

    Schiffman, Jason; Nakamura, Brad; Earleywine, Mitchell; LaBrie, Joseph

    2005-03-30

    The current investigation uses a large non-clinical sample of undergraduate college students (N=189) to investigate schizotypal traits among cannabis and non-cannabis users, as well as the temporal order of the onset of these traits and cannabis use. Findings suggest that regular cannabis users are significantly more prone to cognitive and perceptual distortions as well as disorganization, but not interpersonal deficits, than non-regular users and those who have never used. Additionally, the onset of schizotypal symptoms generally precedes the onset of cannabis use. The findings do not support a causal link between cannabis use and schizotypal traits.

  16. Calcium ionophoretic and apoptotic effects of ferutinin in the human Jurkat T-cell line.

    PubMed

    Macho, Antonio; Blanco-Molina, Magdalena; Spagliardi, Paola; Appendino, Giovanni; Bremner, Paul; Heinrich, Michael; Fiebich, Bernd L; Muñoz, Eduardo

    2004-09-01

    We have investigated the ionophoretic and apoptotic properties of the daucane sesquiterpene ferutinin and three related compounds, ferutidin, 2-alpha-hydroxyferutidin and teferin, all isolated from various species of plants from the genus Ferula. Ferutinin induced a biphasic elevation of intracellular Ca2+ in the leukemia T-cell line, Jurkat. First, a rapid calcium peak was observed and inhibited by BAPTA-AM. This initial calcium mobilization was followed by a sustained elevation, mediated by the entry of extracellular calcium through L-type calcium channels and sensitive to inhibition by EGTA. Moreover, ferutinin-induced apoptosis in Jurkat cells, and this event was preceded, in a cyclosporine-A sensitive manner, by a loss of mitochondrial transmembrane potential (DeltaPsim) and by an increase in intracellular reactive oxygen species. Ferutinin-induced DNA fragmentation was mediated by a caspase-3-dependent pathway, and was initiated independently of any specific phase of the cell cycle. The evaluation of ferutinin analogs in calcium mobilization and apoptosis assays showed strict structure-activity relationships, with p-hydroxylation of the benzoyl moiety being requested for activity.

  17. [Wide QRS tachycardia preceded by pacemaker spikes].

    PubMed

    Romero, M; Aranda, A; Gómez, F J; Jurado, A

    2014-04-01

    The differential diagnosis and therapeutic management of wide QRS tachycardia preceded by pacemaker spike is presented. The pacemaker-mediated tachycardia, tachycardia fibrillo-flutter in patients with pacemakers, and runaway pacemakers, have a similar surface electrocardiogram, but respond to different therapeutic measures. The tachycardia response to the application of a magnet over the pacemaker could help in the differential diagnosis, and in some cases will be therapeutic, as in the case of a tachycardia-mediated pacemaker. Although these conditions are diagnosed and treated in hospitals with catheterization laboratories using the application programmer over the pacemaker, patients presenting in primary care clinic and emergency forced us to make a diagnosis and treat the haemodynamically unstable patient prior to referral.

  18. Cerebral Hypoperfusion Precedes Nausea During Centrifugation

    NASA Technical Reports Server (NTRS)

    Serrador, Jorge M.; Schlegel, Todd T.; Black, F. Owen; Wood, Scott J.

    2004-01-01

    Nausea and motion sickness are important operational concerns for aviators and astronauts. Understanding underlying mechanisms associated with motion sickness may lead to new treatments. The goal of this work was to determine if cerebral blood flow changes precede the development of nausea in motion sick susceptible subjects. Cerebral flow velocity in the middle cerebral artery (transcranial Doppler), blood pressure (Finapres) and end-tidal CO2 were measured while subjects were rotated on a centrifuge (250 degrees/sec). Following 5 min of rotation, subjects were translated 0.504 m off-center, creating a +lGx centripetal acceleration in the nasal-occipital plane. Ten subjects completed the protocol without symptoms while 5 developed nausea (4 while 6ff-center and 1 while rotating on-center). Prior to nausea, subjects had significant increases in blood pressure (+13plus or minus 3 mmHg, P less than 0.05) and cerebrovascular resistance (+46 plus or minus 17%, P less than 0.05) and decreases in cerebral flow velocity both in the second (-13 plus or minus 4%) and last minute (-22 plus or minus 5%) before symptoms (P less than 0.05). In comparison, controls demonstrated no change in blood pressure or cerebrovascular resistance in the last minute of off-center rotation and only a 7 plus or minus 2% decrease in cerebral flow velocity. All subjects had significant hypocapnia (-3.8 plus or minus 0.4 mmHg, P less than 0.05), however this hypocapnia could not fully explain the cerebral hypoperfusion associated with the development of nausea. These data indicate that reductions in cerebral blood flow precede the development of nausea. Further work is necessary to determine what role cerebral hypoperfusion plays in motion sickness and whether cerebral hypoperfusion can be used to predict the development of nausea in susceptible individuals.

  19. Cochlear contributions to the precedence effect.

    PubMed

    Verhulst, Sarah; Bianchi, Federica; Dau, Torsten

    2013-01-01

    Normal-hearing individuals have sharply tuned auditory filters, and consequently their basilar-membrane (BM) impulse responses (IRs) have durations of several ms at frequencies in the range from 0 to 5 kHz. When presenting clicks that are several ms apart, the BM IRs to the individual clicks will overlap in time, giving rise to complex interactions that have not been fully understood in the human cochlea. The perceptual consequences of these BM IR interactions are of interest as lead-lag click pairs are often used to study localization and the precedence effect. The present study aimed at characterizing perceptual consequences of BM IR interactions in individual listeners based on click-evoked otoacoustic emissions (CEOAEs) and auditory brainstem responses (ABRs). Lag suppression, denoting the level difference between the CEOAE or wave-V response amplitude evoked by the first and the second clicks, was observed for inter-click intervals (ICIs) between 1 and 4 ms. Behavioral correlates of lag suppression were obtained for the same individuals by investigating the percept of the lead-lag click pairs presented either monaurally or binaurally. The click pairs were shown to give rise to fusion (i.e., the inability to hear out the second click in a lead-lag click pair), regardless of monaural or binaural presentation. In both cases, the ICI range where the percept was a fused image correlated well with the ICI range for which monaural lag suppression occurred in the CEOAE and ABR (i.e., for ICIs below 4.3 ms). Furthermore, the lag suppression observed in the wave-V amplitudes to binaural stimulation did not show additional contributions to the lag suppression obtained monaurally, suggesting that peripheral lag suppression up to the level of the brainstem is dominant in the perception of the precedence effect.

  20. Interplanetary shocks preceded by solar filament eruptions

    NASA Technical Reports Server (NTRS)

    Cane, H. V.; Kahler, S. W.; Sheeley, N. R., Jr.

    1986-01-01

    The solar and interplanetary characteristics of six interplanetary shock and energetic particle events associated with the eruptions of solar filaments lying outside active regions are discussed. The events are characterized by the familiar double-ribbon H-alpha brightenings observed with large flares, but only very weak soft X-ray and microwave bursts. Both impulsive phases and metric type II bursts are absent in all six events. The energetic particles observed near the earth appear to be accelerated predominantly in the interplanetary shocks. The interplanetary shock speeds are lower and the longitudinal extents considerably less than those of flare-associated shocks. Three of the events were associated with unusual enhancements of singly-ionized helium in the solar wind following the shocks. These enhancements appear to be direct detections of the cool filament material expelled from the corona. It is suggested that these events are part of a spectrum of solar eruptive events which include both weaker events and the large flares. Despite their unimpressive and unreported solar signatures, the quiescent filament eruptions can result in substantial space and geophysical disturbances.

  1. A Solution NMR Investigation into the Early Events of Amelogenin Nanosphere Self-Assembly Initiated with Sodium Chloride or Calcium Chloride

    SciTech Connect

    Buchko, Garry W.; Tarasevich, Barbara J.; Bekhazi, Jacky G.; Snead, Malcolm L.; Shaw, Wendy J.

    2008-12-08

    Using solution-state NMR spectroscopy, new insights into the early intermolecular interactions stabilizing amelogenin supramolecular assembly and the potential role of calcium ions have been discovered. Two-dimensional 1H-15N spectra were recorded for 15N-labeled amelogenin as a function of increasing Ca2+ concentration starting from monomeric conditions. Evidence for protein-protein interactions were observed between residues E18 and E40 in the N-terminus. At higher Ca2+ concentrations there was concurrent involvement of residues in both the N- (Y12-Q56) and the C-terminus (Q144-T171). Neither specific residues nor their stepwise interaction have previously been identified in the initial stages of nanosphere assembly.

  2. White Dwarf Convection Preceding Type Ia Supernovae

    NASA Astrophysics Data System (ADS)

    Zingale, Michael; Almgren, A. S.; Bell, J. B.; Malone, C. M.; Nonaka, A.; Woosley, S. E.

    2010-01-01

    In the single degenerate scenario for Type Ia supernovae, a Chandrasekhar mass white dwarf `simmers' for centuries preceding the ultimate explosion. During this period, reactions near the center drive convection throughout most of the interior of the white dwarf. The details of this convective flow determine how the first flames in the white dwarf ignite. Simulating this phase is difficult because the flows are highly subsonic. Using the low Mach number hydrodynamics code, MAESTRO, we present 3-d, full star models of the final hours of this convective phase, up to the point of ignition of a Type Ia supernova. We discuss the details of the convective velocity field and the locations of the initial hot spots. Finally, we show some preliminary results with rotation. Support for this work came from the DOE/Office of Nuclear Physics, grant No. DE-FG02-06ER41448 (Stony Brook), the SciDAC Program of the DOE Office of Mathematics, Information, and Computational Sciences under the DOE under contract No. DE-AC02-05CH11231 (LBNL), and the DOE SciDAC program, under grant No. DE-FC02-06ER41438 (UCSC). We made use of the jaguar machine via a DOE INCITE allocation at the Oak Ridge Leadership Computational Facility.

  3. Height changes in the epicentral region preceding the January 17, 1994 Northridge earthquake

    USGS Publications Warehouse

    Castle, Robert O.; Packard, Robert F.; Dinitz, Laura B.

    2000-01-01

    Analysis of the results of repeated levelings through the epicentral region of the Mw 6.7, 1994 Northridge earthquake has disclosed the occurrence of differential uplift in this area that preceded the earthquake. Although the distribution of the relevant vertical-control data is somewhat sparse, in both space and time, those data that we have recovered indicate that this uplift exceeded 0.10 m and peaked 20-25 km west of the 1994 epicenter. While our data also indicate that this deformational event must have occurred during the period 1978-1989, evidence based on the character and magnitude of misclosures developed from 1987 and 1989 surveys argue that the deformation occurred largely during the period 1987-1989. The preseismic vertical-displacement field that preceded the Northridge earthquake is similar in form and, less certainly, magnitude to that which preceded the Mw 6.7, 1971 San Fernando earthquake; other possible, but less significant southern California analogues include the deformational events that preceded the Mw 5.3, 1973 Point Mugu and Mw 5.9, 1987 Whittier Narrows earthquakes. The small but growing number of recognized aseismic deformational episodes that preceded small to moderate magnitude earthquakes in southern California suggests that the deployment of the dense array of continuously recording GPS receivers planned for southern California can be expected to detect and more accurately describe such events than was heretofore possible. Moreover, if the relation between the duration of these deformational anomalies and the magnitudes of any ensuing earthquakes can be much more clearly established, the near perfect temporal control on position afforded by GPS suggests that we may be on the threshold of a realistic earthquake warning system.

  4. Reconciling findings of emotion-induced memory enhancement and impairment of preceding items

    PubMed Central

    Knight, Marisa; Mather, Mara

    2009-01-01

    A large body of work reveals that people remember emotionally arousing information better than neutral information. However, previous research reveals contradictory effects of emotional events on memory for neutral events that precede or follow them: in some studies emotionally arousing items impair memory for immediately preceding or following items and in others arousing items enhance memory for preceding items. By demonstrating both emotion-induced enhancement and impairment, Experiments 1 and 2 clarified the conditions under which these effects are likely to occur. The results suggest that emotion-induced enhancement is most likely to occur for neutral items that: (1) precede (and so are poised to predict the onset of) emotionally arousing items, (2) have high attentional weights at encoding, and (3) are tested after a delay period of a week rather than within the same experiment session. In contrast, emotion-induced impairment is most likely to occur for neutral items near the onset of emotional arousal that are overshadowed by highly activated competing items during encoding. PMID:20001121

  5. Revisiting intracellular calcium signaling semantics.

    PubMed

    Haiech, Jacques; Audran, Emilie; Fève, Marie; Ranjeva, Raoul; Kilhoffer, Marie-Claude

    2011-12-01

    Cells use intracellular free calcium concentration changes for signaling. Signal encoding occurs through both spatial and temporal modulation of the free calcium concentration. The encoded message is detected by an ensemble of intracellular sensors forming the family of calcium-binding proteins (CaBPs) which must faithfully translate the message using a new syntax that is recognized by the cell. The cell is home to a significant although limited number of genes coding for proteins involved in the signal encoding and decoding processes. In a cell, only a subset of this ensemble of genes is expressed, leading to a genetic regulation of the calcium signal pathways. Calmodulin (CaM), the most ubiquitous expressed intracellular calcium-binding protein, plays a major role in calcium signal translation. Similar to a hub, it is central to a large and finely tuned network, receiving information, integrating it and dispatching the cognate response. In this review, we examine the different steps starting with an external stimulus up to a cellular response, with special emphasis on CaM and the mechanism by which it decodes calcium signals and translates it into exquisitely coordinated cellular events. By this means, we will revisit the calcium signaling semantics, hoping that we will ease communication between scientists dealing with calcium signals in different biological systems and different domains.

  6. Calcium in diet

    MedlinePlus

    ... of calcium dietary supplements include calcium citrate and calcium carbonate. Calcium citrate is the more expensive form of ... the body on a full or empty stomach. Calcium carbonate is less expensive. It is absorbed better by ...

  7. The ins and outs of mitochondrial calcium.

    PubMed

    Finkel, Toren; Menazza, Sara; Holmström, Kira M; Parks, Randi J; Liu, Julia; Sun, Junhui; Liu, Jie; Pan, Xin; Murphy, Elizabeth

    2015-05-22

    Calcium is thought to play an important role in regulating mitochondrial function. Evidence suggests that an increase in mitochondrial calcium can augment ATP production by altering the activity of calcium-sensitive mitochondrial matrix enzymes. In contrast, the entry of large amounts of mitochondrial calcium in the setting of ischemia-reperfusion injury is thought to be a critical event in triggering cellular necrosis. For many decades, the details of how calcium entered the mitochondria remained a biological mystery. In the past few years, significant progress has been made in identifying the molecular components of the mitochondrial calcium uniporter complex. Here, we review how calcium enters and leaves the mitochondria, the growing insight into the topology, stoichiometry and function of the uniporter complex, and the early lessons learned from some initial mouse models that genetically perturb mitochondrial calcium homeostasis.

  8. Estrogen evokes a rapid effect on intracellular calcium in neurons characterized by calcium oscillations in the arcuate nucleus.

    PubMed

    Fricke, Oliver; Kow, Lee-Ming; Bogun, Magda; Pfaff, Donald W

    2007-06-01

    Rapid estrogen effects became an interesting topic to explain estrogen effects not associated with the classical nuclear pathway. The rapid estrogen effect on intracellular calcium oscillations was characterized in neurons of the arcuate nucleus. Ratiometric calcium imaging (fura-2AM) was used to measure intracellular calcium in brain slices of female Swiss Webster mice (median of age 27 days p.n.). Calcium oscillations were dependent on intracellular calcium and also on calcium influx from the extracellular space. The perfusion of slices with calcium-free solution inhibited spontaneous calcium oscillations. The metabotropic glutamate receptor agonist t-ACPD (5 microM) and low concentrated ryanodine (100 nM) induced intracellular calcium release when slices were perfused with calcium-free solution. 17beta-estradiol (10 nM) also induced intracellular calcium release in calcium-free ACSF. This effect was inhibited by the preceding administration of thapsigargin (2 microM) indicating the association of the rapid estrogen effect with intracellular calcium stores. The administration of the non-selective phospholipase C-inhibitor ET-18 (30 microM), but not U73122 (10 microM), and the inhibition of protein kinase A by H-89 (0.25 microM) suppressed the rapid estrogen effect. Analyses indicated a qualitative, but not quantitatively significant effect of 17beta-estradiol on calcium oscillations.

  9. Calcium - ionized

    MedlinePlus

    ... 245. Read More Acute kidney failure Albumin - blood (serum) test Bone tumor Calcium blood test Hyperparathyroidism Hypoparathyroidism Malabsorption Milk-alkali syndrome Multiple myeloma Osteomalacia Paget disease of the bone Rickets Sarcoidosis Vitamin D Review ...

  10. Calcium Carbonate.

    PubMed

    Al Omari, M M H; Rashid, I S; Qinna, N A; Jaber, A M; Badwan, A A

    2016-01-01

    Calcium carbonate is a chemical compound with the formula CaCO3 formed by three main elements: carbon, oxygen, and calcium. It is a common substance found in rocks in all parts of the world (most notably as limestone), and is the main component of shells of marine organisms, snails, coal balls, pearls, and eggshells. CaCO3 exists in different polymorphs, each with specific stability that depends on a diversity of variables.

  11. Regulation of cardiomyocyte autophagy by calcium.

    PubMed

    Shaikh, Soni; Troncoso, Rodrigo; Criollo, Alfredo; Bravo-Sagua, Roberto; García, Lorena; Morselli, Eugenia; Cifuentes, Mariana; Quest, Andrew F G; Hill, Joseph A; Lavandero, Sergio

    2016-04-15

    Calcium signaling plays a crucial role in a multitude of events within the cardiomyocyte, including cell cycle control, growth, apoptosis, and autophagy. With respect to calcium-dependent regulation of autophagy, ion channels and exchangers, receptors, and intracellular mediators play fundamental roles. In this review, we discuss calcium-dependent regulation of cardiomyocyte autophagy, a lysosomal mechanism that is often cytoprotective, serving to defend against disease-related stress and nutrient insufficiency. We also highlight the importance of the subcellular distribution of calcium and related proteins, interorganelle communication, and other key signaling events that govern cardiomyocyte autophagy.

  12. Calcium Hydroxylapatite

    PubMed Central

    Yutskovskaya, Yana Alexandrovna; Philip Werschler, WM.

    2015-01-01

    Background: Calcium hydroxylapatite is one of the most well-studied dermal fillers worldwide and has been extensively used for the correction of moderate-to-severe facial lines and folds and to replenish lost volume. Objectives: To mark the milestone of 10 years of use in the aesthetic field, this review will consider the evolution of calcium hydroxylapatite in aesthetic medicine, provide a detailed injection protocol for a global facial approach, and examine how the unique properties of calcium hydroxylapatite provide it with an important place in today’s market. Methods: This article is an up-to-date review of calcium hydroxylapatite in aesthetic medicine along with procedures for its use, including a detailed injection protocol for a global facial approach by three expert injectors. Conclusion: Calcium hydroxylapatite is a very effective agent for many areas of facial soft tissue augmentation and is associated with a high and well-established safety profile. Calcium hydroxylapatite combines high elasticity and viscosity with an ability to induce long-term collagen formation making it an ideal agent for a global facial approach. PMID:25610523

  13. Calcium orthophosphates

    PubMed Central

    Dorozhkin, Sergey V.

    2011-01-01

    The present overview is intended to point the readers’ attention to the important subject of calcium orthophosphates. This type of materials is of special significance for human beings, because they represent the inorganic part of major normal (bones, teeth and antlers) and pathological (i.e., those appearing due to various diseases) calcified tissues of mammals. For example, atherosclerosis results in blood vessel blockage caused by a solid composite of cholesterol with calcium orthophosphates, while dental caries and osteoporosis mean a partial decalcification of teeth and bones, respectively, that results in replacement of a less soluble and harder biological apatite by more soluble and softer calcium hydrogenphosphates. Therefore, the processes of both normal and pathological calcifications are just an in vivo crystallization of calcium orthophosphates. Similarly, dental caries and osteoporosis might be considered an in vivo dissolution of calcium orthophosphates. Thus, calcium orthophosphates hold a great significance for humankind, and in this paper, an overview on the current knowledge on this subject is provided. PMID:23507744

  14. Coronal X-ray activity preceding solar flares

    NASA Technical Reports Server (NTRS)

    Webb, D. F.

    1985-01-01

    The characteristics of coronal emplacements preceding solar flares were investigated based on a comprehensive survey of Skylab soft X-ray images. A search interval of 30 min before flare was used in the X-ray observations. X-ray images with preflare enhancements were compared with high resolution H-alpha images and photospheric magnetograms and preflare enhancements were found in a statistically significant number of the observed preflare intervals. The enhancement events consisted of loops, kernels, and sinuous features with one to three separate preflare structures appearing in each interval. Typical gas pressures in the preflare X-ray features were estimated on the order of a few dyne per sq cm and densities were 4-10 x 10 to the -9th per cu cm for assumed average temperatures. H-alpha brightenings in the form of knots and patches were found in conjunction with the X-ray preflare features in nearly all of the intervals. It is concluded that H-alpha emission is characteristic of preflare emission processes. The observational data are interpreted within the framework of existing loop preheating models, and the results are discussed in detail.

  15. Calcium channels and migraine.

    PubMed

    Pietrobon, Daniela

    2013-07-01

    Missense mutations in CACNA1A, the gene that encodes the pore-forming α1 subunit of human voltage-gated Ca(V)2.1 (P/Q-type) calcium channels, cause a rare form of migraine with aura (familial hemiplegic migraine type 1: FHM1). Migraine is a common disabling brain disorder whose key manifestations are recurrent attacks of unilateral headache that may be preceded by transient neurological aura symptoms. This review, first, briefly summarizes current understanding of the pathophysiological mechanisms that are believed to underlie migraine headache, migraine aura and the onset of a migraine attack, and briefly describes the localization and function of neuronal Ca(V)2.1 channels in the brain regions that have been implicated in migraine pathogenesis. Then, the review describes and discusses i) the functional consequences of FHM1 mutations on the biophysical properties of recombinant human Ca(V)2.1 channels and native Ca(V)2.1 channels in neurons of knockin mouse models carrying the mild R192Q or severe S218L mutations in the orthologous gene, and ii) the functional consequences of these mutations on neurophysiological processes in the cerebral cortex and trigeminovascular system thought to be involved in the pathophysiology of migraine, and the insights into migraine mechanisms obtained from the functional analysis of these processes in FHM1 knockin mice. This article is part of a Special Issue entitled: Calcium channels.

  16. A Precedent-setting Case of Dynamic Triggering

    NASA Astrophysics Data System (ADS)

    Gomberg, J. S.

    2013-12-01

    On October 28, 2012 the M7.7 Haida Gwaii, British Columbia earthquake broke the southern end of the Queen Charlotte plate-boundary fault system. Less than 3 months later on January 5, 2013 the M7.5 Craig, Alaska earthquake broke the same fault system ~385 km to the northwest. In its public statements about the Craig earthquake, the US Geological Survey noted its likely causal connection with the Haida Gwaii earthquake three months earlier. This inference was based on the improbability of two large earthquakes with recurrence intervals of hundreds of years or more on the same fault system occurring within the same 3-month interval by chance (the Poisson probability is ~.0004% assuming a 100 yr recurrence interval). What physical processes plausibly connect these two events? Although of the correct sign to encourage failure, static stress changes were more than an order of magnitude smaller than triggering thresholds documented elsewhere, and the duration between the events was too small for accrual of significant visco-elastic stress changes. The M7.7 Haida Gwaii earthquake was noteworthy in many aspects, but most remarkable was that the seismic waves it radiated probably dynamically triggered the M7.5 Craig earthquake thereby setting two new important precedents. First, the magnitude of the triggered earthquake exceeds all previously documented cases of dynamic triggering of frictional, shear failure earthquakes. Second, the extraordinarily large amplitude (peak velocities in excess of 1 cm/s) and long duration (several 100 sec) triggering waves likely resulted from trapping of energy within a sedimentary trough, rather than from focusing due to source effects as in most previous examples of clear dynamic triggering. Unlike source characteristics that vary unpredictably from event to event, the permanence of structural features that act as wave-guides suggests enhanced triggering probabilities in this and likely the numerous other settings. In these settings

  17. 10 CFR 501.10 - Order of precedence.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 10 Energy 4 2010-01-01 2010-01-01 false Order of precedence. 501.10 Section 501.10 Energy DEPARTMENT OF ENERGY (CONTINUED) ALTERNATE FUELS ADMINISTRATIVE PROCEDURES AND SANCTIONS General Provisions § 501.10 Order of precedence. If there is any conflict or inconsistency between the provisions of...

  18. 10 CFR 501.10 - Order of precedence.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 10 Energy 4 2011-01-01 2011-01-01 false Order of precedence. 501.10 Section 501.10 Energy DEPARTMENT OF ENERGY (CONTINUED) ALTERNATE FUELS ADMINISTRATIVE PROCEDURES AND SANCTIONS General Provisions § 501.10 Order of precedence. If there is any conflict or inconsistency between the provisions of...

  19. 10 CFR 501.10 - Order of precedence.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 10 Energy 4 2012-01-01 2012-01-01 false Order of precedence. 501.10 Section 501.10 Energy DEPARTMENT OF ENERGY (CONTINUED) ALTERNATE FUELS ADMINISTRATIVE PROCEDURES AND SANCTIONS General Provisions § 501.10 Order of precedence. If there is any conflict or inconsistency between the provisions of...

  20. 10 CFR 501.10 - Order of precedence.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 10 Energy 4 2013-01-01 2013-01-01 false Order of precedence. 501.10 Section 501.10 Energy DEPARTMENT OF ENERGY (CONTINUED) ALTERNATE FUELS ADMINISTRATIVE PROCEDURES AND SANCTIONS General Provisions § 501.10 Order of precedence. If there is any conflict or inconsistency between the provisions of...

  1. 10 CFR 501.10 - Order of precedence.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 10 Energy 4 2014-01-01 2014-01-01 false Order of precedence. 501.10 Section 501.10 Energy DEPARTMENT OF ENERGY (CONTINUED) ALTERNATE FUELS ADMINISTRATIVE PROCEDURES AND SANCTIONS General Provisions § 501.10 Order of precedence. If there is any conflict or inconsistency between the provisions of...

  2. Subjective Evaluation of Life Events.

    ERIC Educational Resources Information Center

    Fontana, Alan F.; And Others

    1979-01-01

    Surveyed medical/surgical patients concerning life events during the preceding year. Subjective evaluations of events were obtained for dimensions of desirability, adjustment, anticipation, and control. Psychological impairment was associated with subjective evaluations, specifically desirability and adjustment. Inclusion of anticipation and…

  3. Characterization of superoxide overproduction by the D-Loop(Nox4)-Nox2 cytochrome b(558) in phagocytes-Differential sensitivity to calcium and phosphorylation events.

    PubMed

    Carrichon, Laure; Picciocchi, Antoine; Debeurme, Franck; Defendi, Federica; Beaumel, Sylvain; Jesaitis, Algirdas J; Dagher, Marie-Claire; Stasia, Marie-José

    2011-01-01

    NADPH oxidase is a crucial element of phagocytes involved in microbicidal mechanisms. It becomes active when membrane-bound cytochrome b(558), the redox core, is assembled with cytosolic p47(phox), p67(phox), p40(phox), and rac proteins to produce superoxide, the precursor for generation of toxic reactive oxygen species. In a previous study, we demonstrated that the potential second intracellular loop of Nox2 was essential to maintaining NADPH oxidase activity by controlling electron transfer from FAD to O(2). Moreover, replacement of this loop by the Nox4-D-loop (D-loop(Nox4)-Nox2) in PLB-985 cells induced superoxide overproduction. In the present investigation, we demonstrated that both soluble and particulate stimuli were able to induce this superoxide overproduction. Superoxide overproduction was also observed after phosphatidic acid activation in a purified cell-free-system assay. The highest oxidase activity was obtained after ionomycin and fMLF stimulation. In addition, enhanced sensitivity to Ca(2+) influx was shown by thapsigargin, EDTA, or BTP2 treatment before fMLF activation. Mutated cytochrome b(558) was less dependent on phosphorylation triggered by ERK1/2 during fMLF or PMA stimulation and by PI3K during OpZ stimulation. The superoxide overproduction of the D-loop(Nox4)-Nox2 mutant may come from a change of responsiveness to intracellular Ca(2+) level and to phosphorylation events during oxidase activation. Finally the D-loop(Nox4)-Nox2-PLB-985 cells were more effective against an attenuated strain of Pseudomonas aeruginosa compared to WT-Nox2 cells. The killing mechanism was biphasic, an early step of ROS production that was directly bactericidal, and a second oxidase-independent step related to the amount of ROS produced in the first step.

  4. Takotsubo cardiomyopathy and thrombotic thrombocytopenic purpura preceding a lupus diagnosis: a case report.

    PubMed

    Georgiades, F; Demosthenous, S; Braimi, M; Tsitskari, T; Psarelis, S

    2015-11-01

    Takotsubo cardiomyopathy, a rare stress-related cardiomyopathy, has been observed in a few cases secondary to systemic lupus erythematosus (SLE). Herein, we report an unusual case where a postmenopausal woman presented initially with Takotsubo syndrome, later developed thrombotic thrombocytopenic purpura and cerebrovascular events, initially without clinical or laboratory features of SLE. During the course of her illness, she was found to satisfy four of the Systemic Lupus International Collaborating Clinics classification criteria for a SLE diagnosis. This unique presentation of our patient, initially with Takotsubo cardiomyopathy, the development of thrombotic thrombocytopenic purpura and cerebrovascular events preceding the diagnosis of SLE illustrates the importance of clinical observation and follow-up.

  5. Drosophila mushroom body Kenyon cells generate spontaneous calcium transients mediated by PLTX-sensitive calcium channels.

    PubMed

    Jiang, Shaojuan Amy; Campusano, Jorge M; Su, Hailing; O'Dowd, Diane K

    2005-07-01

    Spontaneous calcium oscillations in mushroom bodies of late stage pupal and adult Drosophila brains have been implicated in memory consolidation during olfactory associative learning. This study explores the cellular mechanisms regulating calcium dynamics in Kenyon cells, principal neurons in mushroom bodies. Fura-2 imaging shows that Kenyon cells cultured from late stage Drosophila pupae generate spontaneous calcium transients in a cell autonomous fashion, at a frequency similar to calcium oscillations in vivo (10-20/h). The expression of calcium transients is up regulated during pupal development. Although the ability to generate transients is a property intrinsic to Kenyon cells, transients can be modulated by bath application of nicotine and GABA. Calcium transients are blocked, and baseline calcium levels reduced, by removal of external calcium, addition of cobalt, or addition of Plectreurys toxin (PLTX), an insect-specific calcium channel antagonist. Transients do not require calcium release from intracellular stores. Whole cell recordings reveal that the majority of voltage-gated calcium channels in Kenyon cells are PLTX-sensitive. Together these data show that influx of calcium through PLTX-sensitive voltage-gated calcium channels mediates spontaneous calcium transients and regulates basal calcium levels in cultured Kenyon cells. The data also suggest that these calcium transients represent cellular events underlying calcium oscillations in the intact mushroom bodies. However, spontaneous calcium transients are not unique to Kenyon cells as they are present in approximately 60% of all cultured central brain neurons. This suggests the calcium transients play a more general role in maturation or function of adult brain neurons.

  6. Calcium regulation in endosymbiotic organelles of plants.

    PubMed

    Bussemer, Johanna; Vothknecht, Ute C; Chigri, Fatima

    2009-09-01

    In plant cells calcium-dependent signaling pathways are involved in a large array of biological processes in response to hormones, biotic/abiotic stress signals and a variety of developmental cues. This is generally achieved through binding of calcium to diverse calcium-sensing proteins, which subsequently control downstream events by activating or inhibiting biochemical reactions. Regulation by calcium is considered as a eukaryotic trait and has not been described for prokaryotes. Nevertheless, there is increasing evidence indicating that organelles of prokaryotic origin, such as chloroplasts and mitochondria, are integrated into the calcium-signaling network of the cell. An important transducer of calcium in these organelles appears to be calmodulin. In this review we want to give an overview over present data showing that endosymbiotic organelles harbour calcium-dependent biological processes with a focus on calmodulin-regulation.

  7. HIV legal precedent useful for microbial forensics.

    PubMed

    Budowle, Bruce; Harmon, Rockne

    2005-08-01

    The field of microbial forensics was formalized because of the need for attribution in events where a bioweapon has been used. Microbial forensics has its origins in traditional forensics, microbiology, and epidemiology. Microbial forensics can be defined as a scientific discipline dedicated to analyzing evidence for attribution purposes from a bioterrorism act, biocrime, hoax, or inadvertent microorganism/toxin release. This is a very challenging task, since there are myriad microorganisms that can pose a threat, and analytical methods need to be used reliably. The Scientific Working Group on Microbial Genetics and Forensics (SWGMGF) has addressed some quality assurance and control issues, and particularly validation criteria (focusing on preliminary validation) due to the dynamic nature of evolving investigations. Unique identification of a microorganism may never be possible. Yet, qualitative and/or quantitative assessments of the evidence can be made. One approach to provide direction on gaps in the microbial forensics effort is to perform an end-to-end retrospective analysis of past cases. As an example, the case of a gastroenterologist who was accused of second degree attempted murder of his paramour using HIV as the weapon was reviewed. The scientific evaluation involves epidemiology, molecular biology, phylogenetics, and legal deliberations.

  8. Calcium Test

    MedlinePlus

    ... if a person has symptoms of a parathyroid disorder , malabsorption , or an overactive thyroid. A total calcium level is often measured as part of a routine health screening. It is included in the comprehensive metabolic panel (CMP) and the basic metabolic panel (BMP) , ...

  9. Calcium cyanide

    Integrated Risk Information System (IRIS)

    Jump to main content . Integrated Risk Information System Recent Additions | Contact Us Search : All EPA IRIS • You are here : EPA Home • Research • Environmental Assessment • IRIS • IRIS Summaries Redirect Page As of September 28 , 2010 , the assessment summary for calcium cyanide is included in th

  10. An interplanetary cause of large geomagnetic storms: Fast forward shock overtaking preceding magnetic cloud

    NASA Astrophysics Data System (ADS)

    Wang, Y. M.; Ye, P. Z.; Wang, S.; Xue, X. H.

    2003-07-01

    In the event that occurred during October 3-6, 2000, at least one magnetosonic wave and one fast forward shock advanced into the preceding magnetic cloud (MC). By using the field and plasma data from the ACE and WIND spacecraft, we analyze the evolution of this event, including the characteristics and changes of the magnetic fields and plasma. At the rear part of the cloud, a large southward magnetic field is caused by a shock compression. The shock intensified a preexisting southward magnetic field. This increased the geoeffectiveness of this event and produced an intense geomagnetic storm with Dst = -175 nT. We also describe another event with a shock overtaking a MC on Nov. 6, 2001. A great geomagnetic storm of intensity Dst = 292 nT resulted. These observations are used to argue that shock compression of magnetic cloud fields is an important interplanetary cause of large geomagnetic storms. Our analyses suggest that the geoeffectiveness is related to the direction of preexisting magnetic fields, the intensity of overtaking shock, and the amount of shock penetration into the preceding MC.

  11. Calcium and bone disease

    PubMed Central

    Blair, Harry C.; Robinson, Lisa J.; Huang, Christopher L.-H.; Sun, Li; Friedman, Peter A.; Schlesinger, Paul H.; Zaidi, Mone

    2013-01-01

    Calcium transport and calcium signaling are of basic importance in bone cells. Bone is the major store of calcium and a key regulatory organ for calcium homeostasis. Bone, in major part, responds to calcium-dependent signals from the parathyroids and via vitamin D metabolites, although bone retains direct response to extracellular calcium if parathyroid regulation is lost. Improved understanding of calcium transporters and calcium-regulated cellular processes has resulted from analysis of genetic defects, including several defects with low or high bone mass. Osteoblasts deposit calcium by mechanisms including phosphate and calcium transport with alkalinization to absorb acid created by mineral deposition; cartilage calcium mineralization occurs by passive diffusion and phosphate production. Calcium mobilization by osteoclasts is mediated by acid secretion. Both bone forming and bone resorbing cells use calcium signals as regulators of differentiation and activity. This has been studied in more detail in osteoclasts, where both osteoclast differentiation and motility are regulated by calcium. PMID:21674636

  12. Calcium and Vitamin D

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Calcium is required for the bone formation phase of bone remodeling. Typically about 5 nmol (200 mg) of calcium is removed from the adult skeleton and replaced each day. To supply this amount, one would need to consume about 600 mg of calcium, since calcium is not very efficiently absorbed. Calcium ...

  13. [Does trunk varicosity precede insufficiency of the perforating veins?].

    PubMed

    Bernink, B P

    1983-01-01

    The author discusses the theoretical question of precedence of trunk, or perforator, incompetency. Whatever the case, the treatment is always the same. Drawing attention to the laws published in 1970 determining the opening and closing of small vessels, the author mainly discusses the so-called "balloon effect": of which the "physiological valvule" is a derivation, concluding that trunk varicosity precedes perforating vein incompetence. When the deep system is intact, the author prefers to use the term "blow down", reserving the term "blow out" for secondary varices, the deep system being damaged.

  14. Preceding trauma in childhood hematogenous bone and joint infections.

    PubMed

    Pääkkönen, Markus; Kallio, Markku J T; Lankinen, Petteri; Peltola, Heikki; Kallio, Pentti E

    2014-03-01

    Preceding trauma may play a role in the etiology and pathogenesis of hematogenous bone and joint infections. Among 345 children with an acute hematogenous bone and/or joint infection, 20% reported trauma during a 2-week period leading to infection. Blunt impact, bruises, or excoriations were commonly reported. The rate was similar to that in the general pediatric population obtained from the literature. In the study group, patients with and without trauma were similar in age, serum C-reactive protein and erythrocyte sedimentation rate, length of hospitalization, and late sequelae. Preceding minor trauma did not prove to be significant as an etiological or as a prognostic factor.

  15. Calcium and Vitamin D

    MedlinePlus

    ... A calcium-rich diet (including dairy, nuts, leafy greens and fish) helps to build and protect your ... yogurt and cheese are high in calcium. Certain green vegetables and other foods contain calcium in smaller ...

  16. Coronary Calcium Scan

    MedlinePlus

    ... Scan Coronary Calcium Scan Related Topics Angina Atherosclerosis Coronary Heart Disease Electrocardiogram Heart Attack Send a link to NHLBI ... calcium, or calcifications, are a sign of atherosclerosis, coronary heart disease, or coronary microvascular disease. A coronary calcium scan ...

  17. ATP release due to Thy-1–integrin binding induces P2X7-mediated calcium entry required for focal adhesion formation

    PubMed Central

    Henríquez, Mauricio; Herrera-Molina, Rodrigo; Valdivia, Alejandra; Alvarez, Alvaro; Kong, Milene; Muñoz, Nicolás; Eisner, Verónica; Jaimovich, Enrique; Schneider, Pascal; Quest, Andrew F. G.; Leyton, Lisette

    2011-01-01

    Thy-1, an abundant mammalian glycoprotein, interacts with αvβ3 integrin and syndecan-4 in astrocytes and thus triggers signaling events that involve RhoA and its effector p160ROCK, thereby increasing astrocyte adhesion to the extracellular matrix. The signaling cascade includes calcium-dependent activation of protein kinase Cα upstream of Rho; however, what causes the intracellular calcium transients required to promote adhesion remains unclear. Purinergic P2X7 receptors are important for astrocyte function and form large non-selective cation pores upon binding to their ligand, ATP. Thus, we evaluated whether the intracellular calcium required for Thy-1-induced cell adhesion stems from influx mediated by ATP-activated P2X7 receptors. Results show that adhesion induced by the fusion protein Thy-1-Fc was preceded by both ATP release and sustained intracellular calcium elevation. Elimination of extracellular ATP with Apyrase, chelation of extracellular calcium with EGTA, or inhibition of P2X7 with oxidized ATP, all individually blocked intracellular calcium increase and Thy-1-stimulated adhesion. Moreover, Thy-1 mutated in the integrin-binding site did not trigger ATP release, and silencing of P2X7 with specific siRNA blocked Thy-1-induced adhesion. This study is the first to demonstrate a functional link between αvβ3 integrin and P2X7 receptors, and to reveal an important, hitherto unanticipated, role for P2X7 in calcium-dependent signaling required for Thy-1-stimulated astrocyte adhesion. PMID:21502139

  18. Relationship of superoxide production to cytoplasmic free calcium in human monocytes.

    PubMed Central

    Scully, S P; Segel, G B; Lichtman, M A

    1986-01-01

    Calcium has been proposed as an intracellular second messenger for activation of secretion, phagocytosis, and the oxidative burst of neutrophils. We have examined the role of calcium in human monocyte activation. Concanavalin A (Con A)-stimulated monocytes displayed an increment in cytoplasmic ionized calcium at 31 +/- 6 s and the onset of superoxide production at 61 +/- 9 s. The increase in cytoplasmic calcium invariably preceded the onset of superoxide production. If the external calcium concentration was reduced to less than 28 nM by the addition of 10 mM EGTA, superoxide production was not diminished at 5 min; however, superoxide production decreased thereafter. The Con A-evoked increment in cytoplasmic ionized calcium was blunted upon the addition of EGTA and decreased further with time. Both the production of superoxide and the Con A-evoked increment in cytoplasmic ionized calcium displayed a 50% inhibition after 15 min of calcium depletion and were completely inhibited after 60 min. Total cell calcium fell from 0.7 to 0.5 fmol/cell, and the basal level of ionized calcium fell from 83 to 30 nM after 60 min. Histidine, a strong chelator of divalent cations other than calcium and magnesium, had no effect on monocyte superoxide production or on ionized calcium concentrations, indicating that EGTA inhibition was due to cell calcium depletion. In calcium-depleted cells, Con A did not evoke superoxide production until calcium was restored to the incubation medium. The restoration of calcium to Con A-treated, calcium-depleted monocytes permitted a rapid rise in the cytoplasmic ionized calcium, and the production of superoxide within 9 s. These data suggest that an increase in ionized cytoplasmic calcium is necessary for the activation of monocyte superoxide production by Con A. The rise in ionized calcium in response to Con A results, in part, from an internal redistribution of calcium, which is sufficient to permit superoxide generation. PMID:3007579

  19. Alfalfa suppression of weeds is affected by preceding crop

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Organic producers are seeking alternative tactics for weed control so that they can reduce their need for tillage. In this study, we examined the impact of the preceding crop on alfalfa suppression of weeds. Alfalfa was most competitive with weeds following soybean. When following spring wheat, v...

  20. Cross-frequency interactions in the precedence effect.

    PubMed

    Shinn-Cunningham, B G; Zurek, P M; Durlach, N I; Clifton, R K

    1995-07-01

    This paper concerns the extent to which the precedence effect is observed when leading and lagging sounds occupy different spectral regions. Subjects, listening under headphones, were asked to match the intracranial lateral position of an acoustic pointer to that of a test stimulus composed of two binaural noise bursts with asynchronous onsets, parametrically varied frequency content, and different interaural delays. The precedence effect was measured by the degree to which the interaural delay of the matching pointer was independent of the interaural delay of the lagging noise burst in the test stimulus. The results, like those of Blauert and Divenyi [Acustica 66, 267-274 (1988)], show an asymmetric frequency effect in which the lateralization influence of a lagging high-frequency burst is almost completely suppressed by a leading low-frequency burst, whereas a lagging low-frequency burst is weighted equally with a leading high-frequency burst. This asymmetry is shown to be the result of an inherent low-frequency dominance that is seen even with simultaneous bursts. When this dominance is removed (by attenuating the low-frequency burst) the precedence effect operates with roughly equal strength both upward and downward in frequency. Within the scope of the current study (with lateralization achieved through the use of interaural time differences alone, stimuli from only two frequency bands, and only three subjects performing in all experiments), these results suggest that the precedence effect arises from a fairly central processing stage in which information is combined across frequency.

  1. Independence Pending: Teacher Behaviors Preceding Learner Problem Solving

    ERIC Educational Resources Information Center

    Roesler, Rebecca A.

    2017-01-01

    The purposes of the present study were to identify the teacher behaviors that preceded learners' active participation in solving musical and technical problems and describe learners' roles in the problem-solving process. I applied an original model of problem solving to describe the behaviors of teachers and students in 161 rehearsal frames…

  2. Metrical expectations from preceding prosody influence perception of lexical stress

    PubMed Central

    Brown, Meredith; Salverda, Anne Pier; Dilley, Laura C.; Tanenhaus, Michael K.

    2015-01-01

    Two visual-world experiments tested the hypothesis that expectations based on preceding prosody influence the perception of suprasegmental cues to lexical stress. The results demonstrate that listeners’ consideration of competing alternatives with different stress patterns (e.g., ‘jury/gi’raffe) can be influenced by the fundamental frequency and syllable timing patterns across material preceding a target word. When preceding stressed syllables distal to the target word shared pitch and timing characteristics with the first syllable of the target word, pictures of alternatives with primary lexical stress on the first syllable (e.g., jury) initially attracted more looks than alternatives with unstressed initial syllables (e.g., giraffe). This effect was modulated when preceding unstressed syllables had pitch and timing characteristics similar to the initial syllable of the target word, with more looks to alternatives with unstressed initial syllables (e.g., giraffe) than to those with stressed initial syllables (e.g., jury). These findings suggest that expectations about the acoustic realization of upcoming speech include information about metrical organization and lexical stress, and that these expectations constrain the initial interpretation of suprasegmental stress cues. These distal prosody effects implicate on-line probabilistic inferences about the sources of acoustic-phonetic variation during spoken-word recognition. PMID:25621583

  3. A Precedent for Test Validation. ERIC/TM Digest.

    ERIC Educational Resources Information Center

    Rudner, Lawrence; Farris, Michael P.

    In December 1991, the South Carolina Supreme Court ordered the State Board of Education to stop using the Education Entrance Examination (EEE) for licensing parents who want to teach their children at home. In ruling that the test's validation process did not meet a standard of reasonableness, the Court established a significant precedent for test…

  4. Impact of preceding crop on alfalfa competitiveness with weeds

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Organic producers would like to include no-till practices in their farming systems. We are seeking to develop a continuous no-till system for organic farming, based on a complex rotation that includes a 3-year sequence of alfalfa. In this study, we evaluated impact of preceding crop on weed infest...

  5. 48 CFR 3452.215-33 - Order of precedence.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 7 2010-10-01 2010-10-01 false Order of precedence. 3452.215-33 Section 3452.215-33 Federal Acquisition Regulations System DEPARTMENT OF EDUCATION ACQUISITION REGULATION CLAUSES AND FORMS SOLICITATION PROVISIONS AND CONTRACT CLAUSES Texts of Provisions and...

  6. 5 CFR 178.204 - Order of payment precedence.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ..., money due an employee at the time of the employee's death shall be paid to the person or persons surviving at the date of death, in the following order of precedence, and the payment bars recovery by... employee in a writing received in the employing agency prior to the employee's death; (b) Second, if...

  7. [Health benefits and demerits of calcium nutrition or supplementation in older people].

    PubMed

    Shiraki, Masataka

    2015-10-01

    The benefit of calcium nutrition for health has been believed for a long time. In fact, higher calcium intake is associated with reduction of blood pressure, rate of bone loss after menopause and mild risk reduction of fracture. Since calcium intake from food has not been achieved to be the recommended level, calcium supplementation is widely used especially in the US. However, calcium supplementation has been reported to increase in vascular events, recently. On the other hand, calcium nutrition from foods have not been reported any harmful effect on health. Therefore, calcium effects on health seemed to be composite effects of other nutrients taking together with calcium.

  8. CALCIUM-RICH GAP TRANSIENTS: SOLVING THE CALCIUM CONUNDRUM IN THE INTRACLUSTER MEDIUM

    SciTech Connect

    Mulchaey, John S.; Kollmeier, Juna A.; Kasliwal, Mansi M.

    2014-01-10

    X-ray measurements suggest that the abundance of calcium in the intracluster medium is higher than can be explained using favored models for core-collapse and Type Ia supernovae alone. We investigate whether the ''calcium conundrum'' in the intracluster medium can be alleviated by including a contribution from the recently discovered subclass of supernovae known as calcium-rich gap transients. Although the calcium-rich gap transients make up only a small fraction of all supernovae events, we find that their high calcium yields are sufficient to reproduce the X-ray measurements found for nearby rich clusters. We find the χ{sup 2} goodness-of-fit metric improves from 84 to 2 by including this new class. Moreover, calcium-rich supernovae preferentially occur in the outskirts of galaxies making it easier for the nucleosynthesis products of these events to be incorporated in the intracluster medium via ram-pressure stripping. The discovery of calcium-rich gap transients in clusters and groups far from any individual galaxy suggests that supernovae associated with intracluster stars may play an important role in enriching the intracluster medium. Calcium-rich gap transients may also help explain anomalous calcium abundances in many other astrophysical systems including individual stars in the Milky Way, the halos of nearby galaxies, and the circumgalactic medium. Our work highlights the importance of considering the diversity of supernovae types and corresponding yields when modeling the abundance of the intracluster medium and other gas reservoirs.

  9. Role of calcium and calcium-activated proteases in CYP2E1-dependent toxicity in HEPG2 cells.

    PubMed

    Caro, Andres A; Cederbaum, Arthur I

    2002-01-04

    The objective of this work was to investigate whether CYP2E1- and oxidative stress-dependent toxicity in HepG2 cells is mediated by an increase of cytosolic Ca2+ and activation of Ca2+-modulated processes. HepG2 cells expressing CYP2E1 (E47 cells) or control cells not expressing CYP2E1 (C34 cells) were preloaded with arachidonic acid (AA, up to 10 microm) and, after washing, incubated with iron-nitrilotriacetic acid (up to 100 microm) for variable periods (up to 12 h). Toxicity was greater in E47 cells than in C34 cells at all times and combinations of iron/AA tested. Cytosolic calcium increased with incubation time in both cell lines, but the increase was higher in E47 cells than in C34 cells. The rise in calcium was an early event and preceded the developing toxicity. Toxicity in E47 cells and the increase in Ca2+ were inhibited by omission of Ca2+ from the extracellular medium, and toxicity was restored by reincorporation of Ca2+. An inhibitor of Ca2+ release from intracellular stores did not prevent the toxicity or the increase in Ca2+, reflecting a role for the influx of extracellular Ca2+ in the toxicity. Reactive oxygen production was similar in media with or without calcium, indicating that calcium was not modulating CYP2E1-dependent oxidative stress. Toxicity, lipid peroxidation, and the increase of Ca2+ in E47 cells exposed to iron-AA were inhibited by alpha-tocopherol. E47 cells (but not C34 cells) exposed to iron-AA showed increased calpain activity in situ (40-fold). The toxicity in E47 cells mirrored calpain activation and was inhibited by calpeptin, suggesting that calpain activation plays a causal role in toxicity. These results suggest that CYP2E1-dependent toxicity in this model depends on the activation of lipid peroxidation, followed by an increased influx of extracellular Ca2+ and activation of Ca2+-dependent proteases.

  10. Calcium accentuates injury induced by ethanol in human gastric cells.

    PubMed

    Kokoska, E R; Smith, G S; Deshpande, Y; Wolff, A B; Rieckenberg, C; Miller, T A

    1999-01-01

    The mechanism(s) whereby ethanol induces cellular injury remains poorly understood. Furthermore, the role of calcium in gastric mucosal injury under in vitro conditions is poorly defined. The major objectives of this study were to (1) define the temporal relationship between intracellular calcium accumulation induced by ethanol and cellular injury, (2) characterize the mechanism(s) whereby ethanol increases cellular calcium content, and (3) determine whether calcium removal would attenuate ethanol-induced cellular injury. Human gastric cells (AGS) were used for all experiments. Sustained intracellular calcium accumulation induced by ethanol, but not transient changes, preceded and directly correlated with cellular injury. Cells exposed to damaging concentrations of ethanol demonstrated an initial calcium surge that appeared to be a consequence of inositol 1,4,5-triphosphate (IP3) generation and subsequent internal store release followed by a sustained plateau resulting from extracellular calcium influx through store-operated calcium channels. Finally, both morphologic (cellular injury) and functional (clearance of bovine serum albumin) changes induced by ethanol were significantly attenuated when extracellular Ca(+&plus) influx was prevented, and further decreased when intracellular Ca(++) stores were depleted. These data indicate that calcium plays a significant role in cellular injury induced by ethanol.

  11. Astrocyte calcium signalling orchestrates neuronal synchronization in organotypic hippocampal slices

    PubMed Central

    Sasaki, Takuya; Ishikawa, Tomoe; Abe, Reimi; Nakayama, Ryota; Asada, Akiko; Matsuki, Norio; Ikegaya, Yuji

    2014-01-01

    Astrocytes are thought to detect neuronal activity in the form of intracellular calcium elevations; thereby, astrocytes can regulate neuronal excitability and synaptic transmission. Little is known, however, about how the astrocyte calcium signal regulates the activity of neuronal populations. In this study, we addressed this issue using functional multineuron calcium imaging in hippocampal slice cultures. Under normal conditions, CA3 neuronal networks exhibited temporally correlated activity patterns, occasionally generating large synchronization among a subset of cells. The synchronized neuronal activity was correlated with astrocyte calcium events. Calcium buffering by an intracellular injection of a calcium chelator into multiple astrocytes reduced the synaptic strength of unitary transmission between pairs of surrounding pyramidal cells and caused desynchronization of the neuronal networks. Uncaging the calcium in the astrocytes increased the frequency of neuronal synchronization. These data suggest an essential role of the astrocyte calcium signal in the maintenance of basal neuronal function at the circuit level. PMID:24710057

  12. Foreshock Patterns Preceding Great Earthquakes in the Subduction Zone of Chile

    NASA Astrophysics Data System (ADS)

    Papadopoulos, G. A.; Minadakis, G.

    2016-10-01

    Foreshock activity is considered as one of the most promising precursory changes for the main shock prediction in the short term. Averaging over several foreshock sequences has shown that foreshocks are characterized by distinct 3D patterns: their epicenters move towards the main shock epicenter, event count accelerates, and b-value drops. However, these space-time-size patterns were verified so far only in a very few individual cases mainly due to inadequate seismicity catalogue data. We have investigated 3D foreshock patterns before the M w 8.8 Maule in 27 February 2010, M w 8.1 Iquique in 1 April 2014, and M w 8.4 Illapel in 16 September 2015 great earthquakes in the Chile subduction zone. To avoid biased results, no a priori spatiotemporal definitions of foreshocks were inserted. The procedure was based on pattern recognition from statistically significant seismicity changes in the three domains. The pattern recognition in one domain was independent of the pattern recognition in another domain. We found and verified with two independent catalogue data sets (CSN, IPOC) that within a critical area of ca. 65 km from the main shock epicenter, the 2014 event was preceded by distinct foreshock 3D patterns. A nearly weak foreshock stage (20 January-14 March 2014) was followed by a main-strong stage (15 March-1 April 2014) highly significant in all domains, although foreshock activity slightly decreased in about the last 5 days. Seismic moment release also accelerated in the last stage due to the occurrence of a cluster of very strong foreshock events. Foreshock activity very likely occurred in the hanging-wall fault domain on the South American Plate overriding Nazca Plate. The 2014 foreshock activity was quite similar to the one preceding the 6 Apr. 2009 L' Aquila (Italy) M w 6.3 earthquake associated with normal faulting. Using the 2014 earthquake as a reference event, we observed that similar foreshock 3D patterns preceded the 2010 and 2015 earthquakes within

  13. Case report of unusual leukoencephalopathy preceding primary CNS lymphoma

    PubMed Central

    Brecher, K.; Hochberg, F.; Louis, D.; de la Monte, S.; Riskind, P.

    1998-01-01

    A previously healthy 35 year old woman presented with bilateral uveitus associated with multiple, evolving, non-enhancing white matter lesions consistent with a progressive leukoencephalopathy such as multiple sclerosis. Thirty months after her initial presentation, she was diagnosed with primary CNS lymphoma and died 14 months later. The unusual clinical course preceding the diagnosis suggests that a demyelinating disease may have preceded, and possibly heralded, the development of primary CNS lymphoma. Cases of "sentinel lesions" heralding the diagnosis of primary CNS lymphoma have been reported, and this case further corroborates such instances and raises further issues regarding possible neoplastic transformation occurring in inflammatory diseases such as multiple sclerosis.

 PMID:9854972

  14. Auditory startle reflex inhibited by preceding self-action.

    PubMed

    Kawachi, Yousuke; Matsue, Yoshihiko; Shibata, Michiaki; Imaizumi, Osamu; Gyoba, Jiro

    2014-01-01

    A startle reflex to a startle pulse is inhibited when preceded by a prestimulus. We introduced a key-press action (self-action) or an 85 dB noise burst as a prestimulus, followed by a 115 dB noise burst as a startle pulse. We manipulated temporal offsets between the prestimulus and the startle pulse from 30-1,500 ms to examine whether self-action modulates the startle reflex and the temporal properties of the modulatory effect. We assessed eyeblink reflexes by electromyography. Both prestimuli decreased reflexes compared to pulse-alone trials. Moreover, the temporal windows of inhibition were different between the types of prestimuli. A faster maximal inhibition and narrower temporal window in self-action trials suggest that preceding self-action inhibits the startle reflex and allows prediction of the coming pulse in different ways from auditory prestimuli.

  15. Imaging calcium in neurons.

    PubMed

    Grienberger, Christine; Konnerth, Arthur

    2012-03-08

    Calcium ions generate versatile intracellular signals that control key functions in all types of neurons. Imaging calcium in neurons is particularly important because calcium signals exert their highly specific functions in well-defined cellular subcompartments. In this Primer, we briefly review the general mechanisms of neuronal calcium signaling. We then introduce the calcium imaging devices, including confocal and two-photon microscopy as well as miniaturized devices that are used in freely moving animals. We provide an overview of the classical chemical fluorescent calcium indicators and of the protein-based genetically encoded calcium indicators. Using application examples, we introduce new developments in the field, such as calcium imaging in awake, behaving animals and the use of calcium imaging for mapping single spine sensory inputs in cortical neurons in vivo. We conclude by providing an outlook on the prospects of calcium imaging for the analysis of neuronal signaling and plasticity in various animal models.

  16. Calcium and calcium magnesium carbonate specimens submitted as urinary tract stones.

    PubMed

    Gault, M H; Chafe, L; Longerich, L; Mason, R A

    1993-02-01

    Of 8,129 specimens submitted as urinary stones from 6,095 patients, 67 from 15 patients were predominantly calcium carbonate or calcium magnesium carbonate (dolomite) by infrared analysis. Detailed study of 1 man and 4 women who submitted 3 or more such specimens showed that all were of aragonite calcium carbonate crystal form in 2 women and all calcite in the man. All 3 patients had a long history of nephrolithiasis preceding submission of calcium carbonate stones. There was frequent and often painful spontaneous passage of many small stones. Medullary sponge kidney was reported in 2 patients. Specimens submitted by the other 2 women included dolomite and quartz artifacts. Of the other 10 patients 4 had calcite and 1 had aragonite (possibly true stones). Five patients had artifacts with dolomite in 3 and mixed specimens in 2. True calcium carbonate kidney stones and calcium carbonate artifacts may be difficult to distinguish, and dolomite and quartz artifacts may require x-ray diffraction for clear-cut diagnosis.

  17. Direct In Vivo Manipulation and Imaging of Calcium Transients in Neutrophils Identify a Critical Role for Leading-Edge Calcium Flux.

    PubMed

    Beerman, Rebecca W; Matty, Molly A; Au, Gina G; Looger, Loren L; Choudhury, Kingshuk Roy; Keller, Philipp J; Tobin, David M

    2015-12-15

    Calcium signaling has long been associated with key events of immunity, including chemotaxis, phagocytosis, and activation. However, imaging and manipulation of calcium flux in motile immune cells in live animals remain challenging. Using light-sheet microscopy for in vivo calcium imaging in zebrafish, we observe characteristic patterns of calcium flux triggered by distinct events, including phagocytosis of pathogenic bacteria and migration of neutrophils toward inflammatory stimuli. In contrast to findings from ex vivo studies, we observe enriched calcium influx at the leading edge of migrating neutrophils. To directly manipulate calcium dynamics in vivo, we have developed transgenic lines with cell-specific expression of the mammalian TRPV1 channel, enabling ligand-gated, reversible, and spatiotemporal control of calcium influx. We find that controlled calcium influx can function to help define the neutrophil's leading edge. Cell-specific TRPV1 expression may have broad utility for precise control of calcium dynamics in other immune cell types and organisms.

  18. Foreshock patterns preceding large earthquakes in the subduction zone of Chile

    NASA Astrophysics Data System (ADS)

    Minadakis, George; Papadopoulos, Gerassimos A.

    2016-04-01

    Some of the largest earthquakes in the globe occur in the subduction zone of Chile. Therefore, it is of particular interest to investigate foreshock patterns preceding such earthquakes. Foreshocks in Chile were recognized as early as 1960. In fact, the giant (Mw9.5) earthquake of 22 May 1960, which was the largest ever instrumentally recorded, was preceded by 45 foreshocks in a time period of 33h before the mainshock, while 250 aftershocks were recorded in a 33h time period after the mainshock. Four foreshocks were bigger than magnitude 7.0, including a magnitude 7.9 on May 21 that caused severe damage in the Concepcion area. More recently, Brodsky and Lay (2014) and Bedford et al. (2015) reported on foreshock activity before the 1 April 2014 large earthquake (Mw8.2). However, 3-D foreshock patterns in space, time and size were not studied in depth so far. Since such studies require for good seismic catalogues to be available, we have investigated 3-D foreshock patterns only before the recent, very large mainshocks occurring on 27 February 2010 (Mw 8.8), 1 April 2014 (Mw8.2) and 16 September 2015 (Mw8.4). Although our analysis does not depend on a priori definition of short-term foreshocks, our interest focuses in the short-term time frame, that is in the last 5-6 months before the mainshock. The analysis of the 2014 event showed an excellent foreshock sequence consisting by an early-weak foreshock stage lasting for about 1.8 months and by a main-strong precursory foreshock stage that was evolved in the last 18 days before the mainshock. During the strong foreshock period the seismicity concentrated around the mainshock epicenter in a critical area of about 65 km mainly along the trench domain to the south of the mainshock epicenter. At the same time, the activity rate increased dramatically, the b-value dropped and the mean magnitude increased significantly, while the level of seismic energy released also increased. In view of these highly significant seismicity

  19. Dissociation between emotional and endocrine responses preceding an academic examination in male medical students.

    PubMed

    Allen, P I; Batty, K A; Dodd, C A; Herbert, J; Hugh, C J; Moore, G F; Seymour, M J; Shiers, H M; Stacey, P M; Young, S K

    1985-11-01

    A study was made in 2 consecutive years of the emotional states and morning and afternoon serum levels of prolactin, cortisol and testosterone of male medical students during a 4- to 5-week period preceding a major university examination. 'Distress', 'anxiety' and, to a lesser degree, 'depression' increased during the 2 weeks immediately preceding the examination and were positively correlated with personality anxiety or neuroticism traits. Group means for hormones showed no consistent change over the same period. Neither was there evidence for a correlation between endocrine and emotional changes within individual students during the pre-examination period. A restricted study showed that there were significant increments in cortisol in samples taken during the examination itself. Changes in emotional state before an examination occurred in the absence of equally dramatic changes in levels of the three hormones studied, though this relationship may have altered during the examination itself. This suggests that the factors controlling the two categories of response may relate differently, in some way, to the imminence of this stressful event.

  20. Baseline activity predicts working memory load of preceding task condition.

    PubMed

    Pyka, Martin; Hahn, Tim; Heider, Dominik; Krug, Axel; Sommer, Jens; Kircher, Tilo; Jansen, Andreas

    2013-11-01

    The conceptual notion of the so-called resting state of the brain has been recently challenged by studies indicating a continuing effect of cognitive processes on subsequent rest. In particular, activity in posterior parietal and medial prefrontal areas has been found to be modulated by preceding experimental conditions. In this study, we investigated which brain areas show working memory dependent patterns in subsequent baseline periods and how specific they are for the preceding experimental condition. During functional magnetic resonance imaging, 94 subjects performed a letter-version of the n-back task with the conditions 0-back and 2-back followed by a low-level baseline in which subjects had to passively observe the letters appearing. In a univariate analysis, 2-back served as control condition while 0-back, baseline after 0-back and baseline after 2-back were modeled as regressors to test for activity changes between both baseline conditions. Additionally, we tested, using Gaussian process classifiers, the recognition of task condition from functional images acquired during baseline. Besides the expected activity changes in the precuneus and medial prefrontal cortex, we found differential activity in the thalamus, putamen, and postcentral gyrus that were affected by the preceding task. The multivariate analysis revealed that images of the subsequent baseline block contain task related patterns that yield a recognition rate of 70%. The results suggest that the influence of a cognitive task on subsequent baseline is strong and specific for some areas but not restricted to areas of the so-called default mode network.

  1. Vitiligo disease triggers: psychological stressors preceding the onset of disease.

    PubMed

    Silverberg, Jonathan I; Silverberg, Nanette B

    2015-05-01

    Vitiligo is the loss of skin pigmentation caused by autoimmune destruction of melanocytes. Little is known about the impact of psychological stressors preceding vitiligo onset on symptoms associated with vitiligo and the extent of disease. We performed a questionnaire-based study of 1541 adults with vitiligo to evaluate the impact of psychological stressors in this patient population. Psychological stressors should be considered as potential disease triggers in vitiligo patients, and screening of vitiligo patients for psychological stressors and associated symptoms should be included in routine assessment.

  2. CALCIUM CHLORIDE PLANT LOOKING EAST. CALCIUM CHLORIDE BUILDING IN CENTER, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    CALCIUM CHLORIDE PLANT LOOKING EAST. CALCIUM CHLORIDE BUILDING IN CENTER, CALCIUM CHLORIDE STORAGE BUILDING ON RIGHT WITH SA (SODA ASH) BUILDING IN RIGHT BACKGROUND. - Solvay Process Company, Calcium Chloride Plant, Between Willis & Milton Avenues, Solvay, Onondaga County, NY

  3. [Do cows drink calcium?].

    PubMed

    Geishauser, T; Lechner, S; Plate, I; Heidemann, B

    2008-03-01

    The objective of this study was to investigate how well cows drink the Propeller calcium drink, and it's effect on blood calcium concentration. Drinking was tested in 120 cows right after calving, before cows drank anything else. 60 cows each were offered 20 liters of Propeller calcium drink or 20 liters of water. Cows drank the Propeller as good as water. 72% of all cows drank all 20 liters, 18% drank on average 8.2 liters and 10% drank less than 1 liter. Blood calcium concentration was studied in 16 cows right after calving. Eight cows each were offered 20 liters of Propeller calcium drink or no calcium drink. Blood calcium significantly increased ten minutes after Propeller intake and stayed significantly elevated for 24 hours. Without calcium drink blood calcium levels decreased significantly. Advantages of the new Propeller calcium drink over calcium gels or boli could be that cows now drink calcium themselves and that the Propeller increases blood calcium concentration rapidly and long lasting.

  4. Energy crisis precedes global metabolic failure in a novel Caenorhabditis elegans Alzheimer Disease model.

    PubMed

    Fong, Sheng; Teo, Emelyne; Ng, Li Fang; Chen, Ce-Belle; Lakshmanan, Lakshmi Narayanan; Tsoi, Sau Yee; Moore, Philip Keith; Inoue, Takao; Halliwell, Barry; Gruber, Jan

    2016-09-22

    Alzheimer Disease (AD) is a progressive neurological disorder characterized by the deposition of amyloid beta (Aβ), predominantly the Aβ1-42 form, in the brain. Mitochondrial dysfunction and impaired energy metabolism are important components of AD pathogenesis. However, the causal and temporal relationships between them and AD pathology remain unclear. Using a novel C. elegans AD strain with constitutive neuronal Aβ1-42 expression that displays neuromuscular defects and age-dependent behavioural dysfunction reminiscent of AD, we have shown that mitochondrial bioenergetic deficit is an early event in AD pathogenesis, preceding dysfunction of mitochondrial electron transfer chain (ETC) complexes and the onset of global metabolic failure. These results are consistent with an emerging view that AD may be a metabolic neurodegenerative disease, and also confirm that Aβ-driven metabolic and mitochondrial effects can be reproduced in organisms separated by large evolutionary distances.

  5. Complex Admixture Preceded and Followed the Extinction of Wisent in the Wild

    PubMed Central

    Hartmann, Stefanie; Paijmans, Johanna L. A.; Taron, Ulrike; Xenikoudakis, Georgios; Cahill, James A.; Heintzman, Peter D.; Shapiro, Beth; Baryshnikov, Gennady; Bunevich, Aleksei N.; Crees, Jennifer J.; Dobosz, Roland; Manaserian, Ninna; Okarma, Henryk; Tokarska, Małgorzata; Turvey, Samuel T.; Wójcik, Jan M.; Żyła, Waldemar; Szymura, Jacek M.; Hofreiter, Michael

    2017-01-01

    Retracing complex population processes that precede extreme bottlenecks may be impossible using data from living individuals. The wisent (Bison bonasus), Europe’s largest terrestrial mammal, exemplifies such a population history, having gone extinct in the wild but subsequently restored by captive breeding efforts. Using low coverage genomic data from modern and historical individuals, we investigate population processes occurring before and after this extinction. Analysis of aligned genomes supports the division of wisent into two previously recognized subspecies, but almost half of the genomic alignment contradicts this population history as a result of incomplete lineage sorting and admixture. Admixture between subspecies populations occurred prior to extinction and subsequently during the captive breeding program. Admixture with the Bos cattle lineage is also widespread but results from ancient events rather than recent hybridization with domestics. Our study demonstrates the huge potential of historical genomes for both studying evolutionary histories and for guiding conservation strategies. PMID:28007976

  6. Source analysis of stimulus-preceding negativity constrained by functional magnetic resonance imaging.

    PubMed

    Kotani, Yasunori; Ohgami, Yoshimi; Ishiwata, Takayuki; Arai, Jun-Ichirou; Kiryu, Shigeru; Inoue, Yusuke

    2015-10-01

    The stimulus-preceding negativity (SPN) is an event-related potential (ERP) reflecting anticipation. The anterior insular cortex is assumed to be one of the physiological sources of the SPN. However, the precise neural substrates of the SPN have yet to be confirmed. We therefore performed separate functional magnetic resonance imaging (fMRI) and ERP studies using the same time estimation task, followed by fMRI-constrained ERP source analysis. Dipole locations were determined by the fMRI results, while the time courses of dipole activities were modeled by the ERP data. Analysis revealed that the right anterior insula was significantly activated before delivery of the feedback stimulus, whereas the left anterior insula was not, and that the SPN mainly arose from four groups of brain regions related to, respectively: (1) the salience network, (2) reward expectation, (3) perceptual anticipation, and (4) arousal. The results suggest that the SPN pertains to multiple brain functions with complex interactions.

  7. The tailings dam failure of 5 November 2015 in SE Brazil and its preceding seismic sequence

    NASA Astrophysics Data System (ADS)

    Agurto-Detzel, H.; Bianchi, M.; Assumpção, M.; Schimmel, M.; Collaço, B.; Ciardelli, C.; Barbosa, J. R.; Calhau, J.

    2016-05-01

    The collapse of a mine tailings dam and subsequent flood in SE Brazil on 5 November 2015 was preceded by a small-magnitude seismic sequence. In this report, we explore the spatiotemporal associations between the seismic events and the accident and discuss their possible connection. We also analyze the signals generated by the turbulent mudflow, as recorded by the Brazilian Seismographic Network (RSBR). In light of our observations, we propose as possible contributing factor for the dam collapse either ground shaking and/or soil liquefaction triggered by the earthquakes. The possibility of such a small-magnitude earthquake contributing to the collapse of a tailings dam raises important concerns regarding safety and related legislation of dams in Brazil and the world.

  8. Possible deep fault slip preceding the 2004 Parkfield earthquake, inferred from detailed observations of tectonic tremor

    USGS Publications Warehouse

    Shelly, D.R.

    2009-01-01

    Earthquake predictability depends, in part, on the degree to which sudden slip is preceded by slow aseismic slip. Recently, observations of deep tremor have enabled inferences of deep slow slip even when detection by other means is not possible, but these data are limited to certain areas and mostly the last decade. The region near Parkfield, California, provides a unique convergence of several years of high-quality tremor data bracketing a moderate earthquake, the 2004 magnitude 6.0 event. Here, I present detailed observations of tectonic tremor from mid-2001 through 2008 that indicate deep fault slip both before and after the Parkfield earthquake that cannot be detected with surface geodetic instruments. While there is no obvious short-term precursor, I find unidirectional tremor migration accompanied by elevated tremor rates in the 3 months prior to the earthquake, which suggests accelerated creep on the fault ???16 km beneath the eventual earthquake hypocenter. Copyright 2009 by the American Geophysical Union.

  9. Arterial stiffening precedes systolic hypertension in diet-induced obesity.

    PubMed

    Weisbrod, Robert M; Shiang, Tina; Al Sayah, Leona; Fry, Jessica L; Bajpai, Saumendra; Reinhart-King, Cynthia A; Lob, Heinrich E; Santhanam, Lakshmi; Mitchell, Gary; Cohen, Richard A; Seta, Francesca

    2013-12-01

    Stiffening of conduit arteries is a risk factor for cardiovascular morbidity. Aortic wall stiffening increases pulsatile hemodynamic forces that are detrimental to the microcirculation in highly perfused organs, such as the heart, brain, and kidney. Arterial stiffness is associated with hypertension but presumed to be due to an adaptive response to increased hemodynamic load. In contrast, a recent clinical study found that stiffness precedes and may contribute to the development of hypertension although the mechanisms underlying hypertension are unknown. Here, we report that in a diet-induced model of obesity, arterial stiffness, measured in vivo, develops within 1 month of the initiation of the diet and precedes the development of hypertension by 5 months. Diet-induced obese mice recapitulate the metabolic syndrome and are characterized by inflammation in visceral fat and aorta. Normalization of the metabolic state by weight loss resulted in return of arterial stiffness and blood pressure to normal. Our findings support the hypothesis that arterial stiffness is a cause rather than a consequence of hypertension.

  10. Human behavior preceding dog bites to the face.

    PubMed

    Rezac, P; Rezac, K; Slama, P

    2015-12-01

    Facial injuries caused by dog bites pose a serious problem. The aims of this study were to determine human behavior immediately preceding a dog bite to the face and to assess the effects of victim age and gender and dog sex and size on the location of the bite to the face and the need for medical treatment. Complete data on 132 incidents of bites to the face were analysed. A human bending over a dog, putting the face close to the dog's face, and gazing between victim and dog closely preceded a dog bite to the face in 76%, 19% and 5% of cases, respectively. More than half of the bites were directed towards the central area of the victim's face (nose, lips). More than two thirds of the victims were children, none of the victims was an adult dog owner and only adult dogs bit the face. Victim's age and gender and dog's sex and size did not affect the location of the bite on the face. People who were bitten by large dogs sought medical treatment more often than people who were bitten by small dogs (P <0.01). Risk factors such as bending over the dog, putting the face close to the dog's face and gazing between human and dog should be avoided, and children should be carefully and constantly supervised when in the presence of dogs.

  11. Preceding Inhibition Silences Layer 6 Neurons in Auditory Cortex

    PubMed Central

    Zhou, Yi; Liu, Bao-hua; Wu, Guangying K.; Kim, Young; Xiao, Zhongju; Tao, Huizhong W.; Zhang, Li I.

    2010-01-01

    Summary A canonical feedforward circuit is proposed to underlie sensory cortical responses with balanced excitation and inhibition in layer 4 (L4). However, in another input layer, L6, sensory responses and the underlying synaptic circuits remain largely unclear. Here, cell-attached recordings in rat primary auditory cortex revealed that for the majority of L6 excitatory neurons, tonal stimuli did not drive spike responses, but suppressed spontaneous firings. Whole-cell recordings further revealed that the silencing resulted from tone-evoked strong inhibition arriving earlier than excitation. This pattern of inputs can be attributed to a parallel feedforward circuit with both excitatory and inhibitory inputs disynaptically relayed. In contrast, in the other neurons directly driven by thalamic input, stimuli evoked excitation preceding relatively weak inhibition, resulting in robust spike responses. Thus, the dichotomy of L6 response properties arises from two distinct patterns of excitatory-inhibitory interplay. The parallel circuit module generating preceding inhibition may provide a gating mechanism for conditional corticothalamic feedback. PMID:20223205

  12. Perturbation of old knowledge precedes integration of new knowledge.

    PubMed

    Fang, Xiaoping; Perfetti, Charles A

    2017-03-14

    The importance of memory consolidation in integrating new knowledge has received much recent attention in the field of word learning. Less examined is the change in existing word knowledge as a result of learning, which we hypothesize to occur prior to the opportunity for consolidation. To test this, we had participants learn new meanings for known words and novel words. Then they performed a one-back task on a list of words that included the trained words followed by words that probed either their new or original meanings while EEGs were recorded. A probe word related to the new meaning of the preceding trained word did not show an N400 reduction compared to an unrelated word, suggesting that the new meaning had not been fully integrated, consistent with one account of complementary learning systems. However, when the probe word was related to the original meaning of the preceding trained word a perturbation effect was observed, indicated by a larger negativity at the central midline cluster (Cz) within 500-700 ms when the trained word had a new meaning than when presented as an exposure control. The perturbation effect suggests that even before a new meaning has become integrated with a word form, the attempt to learn a new meaning temporarily makes the original meaning of a word less accessible.

  13. Effect of interstitial fluid on the fraction of flow microstates that precede clogging in granular hoppers

    NASA Astrophysics Data System (ADS)

    Koivisto, Juha; Durian, Douglas J.

    2017-03-01

    We report on the nature of flow events for the gravity-driven discharge of glass beads through a hole that is small enough that the hopper is susceptible to clogging. In particular, we measure the average and standard deviation of the distribution of discharged masses as a function of both hole and grain sizes. We do so in air, which is usual, but also with the system entirely submerged under water. This damps the grain dynamics and could be expected to dramatically affect the distribution of the flow events, which are described in prior work as avalanche-like. Though the flow is slower and the events last longer, we find that the average discharge mass is only slightly reduced for submerged grains. Furthermore, we find that the shape of the distribution remains exponential, implying that clogging is still a Poisson process even for immersed grains. Per Thomas and Durian [Phys. Rev. Lett. 114, 178001 (2015), 10.1103/PhysRevLett.114.178001], this allows for an interpretation of the average discharge mass in terms of the fraction of flow microstates that precede, i.e., that effectively cause, a stable clog to form. Since this fraction is barely altered by water, we conclude that the crucial microscopic variables are the grain positions; grain momenta play only a secondary role in destabilizing weak incipient arches. These insights should aid ongoing efforts to understand the susceptibility of granular hoppers to clogging.

  14. Calcium and Mitosis

    NASA Technical Reports Server (NTRS)

    Hepler, P.

    1983-01-01

    Although the mechanism of calcium regulation is not understood, there is evidence that calcium plays a role in mitosis. Experiments conducted show that: (1) the spindle apparatus contains a highly developed membrane system that has many characteristics of sarcoplasmic reticulum of muscle; (2) this membrane system contains calcium; and (3) there are ionic fluxes occurring during mitosis which can be seen by a variety of fluorescence probes. Whether the process of mitosis can be modulated by experimentally modulating calcium is discussed.

  15. Calcium supplements and cardiovascular risk: 5 years on.

    PubMed

    Bolland, Mark J; Grey, Andrew; Reid, Ian R

    2013-10-01

    Calcium supplements have been widely used by older men and women. However, in little more than a decade, authoritative recommendations have changed from encouraging the widespread use of calcium supplements to stating that they should not be used for primary prevention of fractures. This substantial shift in recommendations has occurred as a result of accumulated evidence of marginal antifracture efficacy, and important adverse effects from large randomized controlled trials of calcium or coadministered calcium and vitamin D supplements. In this review, we discuss this evidence, with a particular focus on increased cardiovascular risk with calcium supplements, which we first described 5 years ago. Calcium supplements with or without vitamin D marginally reduce total fractures but do not prevent hip fractures in community-dwelling individuals. They also cause kidney stones, acute gastrointestinal events, and increase the risk of myocardial infarction and stroke. Any benefit of calcium supplements on preventing fracture is outweighed by increased cardiovascular events. While there is little evidence to suggest that dietary calcium intake is associated with cardiovascular risk, there is also little evidence that it is associated with fracture risk. Therefore, for the majority of people, dietary calcium intake does not require close scrutiny. Because of the unfavorable risk/benefit profile, widespread prescribing of calcium supplements to prevent fractures should be abandoned. Patients at high risk of fracture should be encouraged to take agents with proven efficacy in preventing vertebral and nonvertebral fractures.

  16. Calcium and bones

    MedlinePlus

    ... very bad at absorbing calcium. Most people absorb only 15% to 20% of the calcium they eat in their diet. Vitamin D is the hormone that helps the gut absorb more calcium. Many older adults have common risks that make bone health worse. ...

  17. Get Enough Calcium

    MedlinePlus

    ... a food with 45% DV of calcium. Check food labels. The Daily Value (DV) on a food label tells you the amount of a nutrient (like ... serving, or 60% DV. Learn how to check food labels for calcium information. Use this calcium shopping list ...

  18. Calcium and calcium isotope changes during carbon cycle perturbations at the end-Permian

    NASA Astrophysics Data System (ADS)

    Komar, N.; Zeebe, R. E.

    2016-01-01

    Negative carbon and calcium isotope excursions, as well as climate shifts, took place during the most severe mass extinction event in Earth's history, the end-Permian (˜252 Ma). Investigating the connection between carbon and calcium cycles during transient carbon cycle perturbation events, such as the end-Permian, may help resolve the intricacies between the coupled calcium-carbon cycles, as well as provide a tool for constraining the causes of mass extinction. Here we identify the deficiencies of a simplified calcium model employed in several previous studies, and we demonstrate the importance of a fully coupled carbon cycle model when investigating the dynamics of carbon and calcium cycling. Simulations with a modified version of the Long-term Ocean-atmosphere-Sediment CArbon cycle Reservoir model, which includes a fully coupled carbon-calcium cycle, indicate that increased weathering rates and ocean acidification (potentially caused by Siberian Trap volcanism) are not capable of producing trends observed in the record, as previously claimed. Our model results suggest that combined effects of carbon input via Siberian Trap volcanism (12,000 Pg C), the cessation of biological carbon export, and variable calcium isotope fractionation (due to a change in the seawater carbonate ion concentration) represents a more plausible scenario. This scenario successfully reconciles δ13C and δ44Ca trends observed in the sediment record, as well as the proposed warming of >6°C.

  19. Calcium and calcium isotope changes during carbon cycle perturbations at the end-Permian

    NASA Astrophysics Data System (ADS)

    Komar, Nemanja; Zeebe, Richard

    2016-04-01

    Negative carbon and calcium isotope excursions, as well as climate shifts, took place during the most severe mass extinction event in Earth's history, the end-Permian (˜252 Ma). Investigating the connection between carbon and calcium cycles during transient carbon cycle perturbation events, such as the end-Permian, may help resolve the intricacies between the coupled calcium-carbon cycles, as well as provide a tool for constraining the causes of mass extinction. Here, we identify the deficiencies of a simplified calcium model employed in several previous studies and we demonstrate the importance of a fully coupled carbon-cycle model when investigating the dynamics of carbon and calcium cycling. Simulations with a modified version of the LOSCAR model, which includes a fully coupled carbon-calcium cycle, indicate that increased weathering rates and ocean acidification (potentially caused by Siberian Trap volcanism) are not capable of producing trends observed in the record, as previously claimed. Our model results suggest that combined effects of carbon input via Siberian Trap volcanism (12,000 Pg C), the cessation of biological carbon export, and variable calcium isotope fractionation (due to a change in the seawater carbonate ion concentration) represents a more plausible scenario. This scenario successfully reconciles δ13C and δ44Ca trends observed in the sediment record, as well as the proposed warming of >6oC.

  20. 26 CFR 25.2504-2 - Determination of gifts for preceding calendar periods.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 26 Internal Revenue 14 2014-04-01 2013-04-01 true Determination of gifts for preceding calendar... § 25.2504-2 Determination of gifts for preceding calendar periods. (a) Gifts made before August 6, 1997... a preceding calendar period, as defined in § 25.2502-1(c)(2), the gift was made prior to August...

  1. 26 CFR 25.2504-2 - Determination of gifts for preceding calendar periods.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 26 Internal Revenue 14 2010-04-01 2010-04-01 false Determination of gifts for preceding calendar... § 25.2504-2 Determination of gifts for preceding calendar periods. (a) Gifts made before August 6, 1997... a preceding calendar period, as defined in § 25.2502-1(c)(2), the gift was made prior to August...

  2. 26 CFR 25.2504-2 - Determination of gifts for preceding calendar periods.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 26 Internal Revenue 14 2012-04-01 2012-04-01 false Determination of gifts for preceding calendar... § 25.2504-2 Determination of gifts for preceding calendar periods. (a) Gifts made before August 6, 1997... a preceding calendar period, as defined in § 25.2502-1(c)(2), the gift was made prior to August...

  3. 26 CFR 25.2504-2 - Determination of gifts for preceding calendar periods.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 26 Internal Revenue 14 2011-04-01 2010-04-01 true Determination of gifts for preceding calendar... § 25.2504-2 Determination of gifts for preceding calendar periods. (a) Gifts made before August 6, 1997... a preceding calendar period, as defined in § 25.2502-1(c)(2), the gift was made prior to August...

  4. 26 CFR 25.2504-2 - Determination of gifts for preceding calendar periods.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 26 Internal Revenue 14 2013-04-01 2013-04-01 false Determination of gifts for preceding calendar... § 25.2504-2 Determination of gifts for preceding calendar periods. (a) Gifts made before August 6, 1997... a preceding calendar period, as defined in § 25.2502-1(c)(2), the gift was made prior to August...

  5. 17 CFR 240.11a1-1(T) - Transactions yielding priority, parity, and precedence.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ..., parity, and precedence. 240.11a1-1(T) Section 240.11a1-1(T) Commodity and Securities Exchanges SECURITIES... (rule 11a-1) § 240.11a1-1(T) Transactions yielding priority, parity, and precedence. (a) A transaction... priority, parity, and precedence in execution to orders for the account of persons who are not members...

  6. 17 CFR 240.11a1-1(T) - Transactions yielding priority, parity, and precedence.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ..., parity, and precedence. 240.11a1-1(T) Section 240.11a1-1(T) Commodity and Securities Exchanges SECURITIES... (rule 11a-1) § 240.11a1-1(T) Transactions yielding priority, parity, and precedence. (a) A transaction... priority, parity, and precedence in execution to orders for the account of persons who are not members...

  7. 17 CFR 240.11a1-1(T) - Transactions yielding priority, parity, and precedence.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ..., parity, and precedence. 240.11a1-1(T) Section 240.11a1-1(T) Commodity and Securities Exchanges SECURITIES... (rule 11a-1) § 240.11a1-1(T) Transactions yielding priority, parity, and precedence. (a) A transaction... priority, parity, and precedence in execution to orders for the account of persons who are not members...

  8. 17 CFR 240.11a1-1(T) - Transactions yielding priority, parity, and precedence.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ..., parity, and precedence. 240.11a1-1(T) Section 240.11a1-1(T) Commodity and Securities Exchanges SECURITIES... (rule 11a-1) § 240.11a1-1(T) Transactions yielding priority, parity, and precedence. (a) A transaction... priority, parity, and precedence in execution to orders for the account of persons who are not members...

  9. 17 CFR 240.11a1-1(T) - Transactions yielding priority, parity, and precedence.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ..., parity, and precedence. 240.11a1-1(T) Section 240.11a1-1(T) Commodity and Securities Exchanges SECURITIES... (rule 11a-1) § 240.11a1-1(T) Transactions yielding priority, parity, and precedence. (a) A transaction... priority, parity, and precedence in execution to orders for the account of persons who are not members...

  10. Revisiting Precede-Proceed: A Leading Model for Ecological and Ethical Health Promotion

    ERIC Educational Resources Information Center

    Porter, Christine M.

    2016-01-01

    Background: The Precede-Proceed model has provided moral and practical guidance for the fields of health education and health promotion since Lawrence Green first developed Precede in 1974 and Green and Kreuter added Proceed in 1991. Precede-Proceed today remains the most comprehensive and one of the most used approaches to promoting health.…

  11. Changes in autonomic activity preceding onset of nonsustained ventricular tachycardia

    NASA Technical Reports Server (NTRS)

    Osaka, M.; Saitoh, H.; Sasabe, N.; Atarashi, H.; Katoh, T.; Hayakawa, H.; Cohen, R. J.

    1996-01-01

    Background: The triggering role of the autonomic nervous system in the initiation of ventricular tachycardia has not been established. To investigate the relationship between changes in autonomic activity and the occurrence of nonsustained ventricular tachycardia (NSVT) we examined heart rate variability (HRV) during the 2-hour period preceding spontaneous episodes of NSVT. Twenty-four subjects were identified retrospectively as having had one episode of NSVT during 24-hour Holter ECC recording. Methods: We measured the mean interval between normal heats (meanRR), the standard deviation of the intervals between beats (SD), the percentage of counts of sequential intervals between normal beats with a change of >50 ms (%RR50), the logarithms of low- and high-frequency spectral components (lnLF, lnHF) of HRV for sequential 10-minute segments preceding NSVT. The correlation dimension (CDim) of HRV was calculated similarly for sequential 20-minute segments. We assessed the significance of the time-course change of each marker over the 120-minute period prior to NSVT onset. Results: MeanRR (P < 0.05), lnLF (P < 0.0001), lnHF (P < 0.0001), the natural logarithm of the ratio of LF to HF (ln[LF/HF]; P < 0.05), and CDim (P < 0.05) showed significant time-course changes during that period, while SD and %RR50 did not. MeanRR, lnLF, lnHF, and CDim all decreased prior to the onset of NSVT, whereas ln(LF/HF) increased. We divided the subjects into two groups: one consisting of 12 patients with coronary artery disease; and the second group of 12 patients without known coronary artery disease. Both groups showed significant changes (P < 0.05) of CDim, lnLF, and lnHF preceding the episodes of NSVT. Conclusions: Changes in the pattern of HRV prior to the onset of episodes of NSVT suggest that changes in autonomic activity may commonly play a role in the triggering of spontaneous episodes of NSVT in susceptible patients. The measured changes suggest a reduction in parasympathetic

  12. The physics of charge separation preceding lightning strokes in thunderclouds

    NASA Technical Reports Server (NTRS)

    Kyrala, Ali

    1987-01-01

    The physics of charge separation preceding lightning strokes in thunderclouds is presented by three types of arguments: An explanation is given for the aggregation of electrical charges of like sign overcoming Coulomb repulsion by attraction due to exchange interaction. The latter is well known in quantum mechanics from the theories of the nuclear bond and the covalent bond. A classical electrostatic model of charge balls of segregated positive and negative charges in the thundercloud is presented. These charge balls can only be maintained in temporarily stable locations by a containing vortex. Because they will be of different sizes and masses, they will stabilize at different altitudes when drag forces are included with the given electrostatic force. The question of how the charges become concentrated again after lightning discharges is approached by means of the collisional Boltzmann transport equation to explain quasi-periodic recharging. It is shown that solutions cannot be separable in both position and time if they are to represent aggregation.

  13. Tumor diagnosis preceding Parkinson's disease: a case-control study.

    PubMed

    D'Amelio, Marco; Ragonese, Paolo; Morgante, Letterio; Epifanio, Antonio; Callari, Graziella; Salemi, Giuseppe; Savettieri, Giovanni

    2004-07-01

    Lower cancer risk in Parkinson's disease (PD) patients compared to the general population has been reported. However, most of the studies were based on death certificates. We designed a case-control study to estimate the association of tumor preceding PD onset and PD. PD patients were matched by age and gender to PD-free individuals, randomly selected from the municipalities of residence of cases. Occurrence of tumors preceding PD onset was assessed through a structured questionnaire. Neoplasms were categorized as benign, malignant, or of uncertain classification, and endocrine-related or not. Odds ratios (OR) were calculated using conditional logistic regression and adjusted for tumor categories and risk factors. We included 222 PD patients. Frequency of cancer was 6.8% for cases, 12.6% for controls. PD patients had a decreased risk for neoplasms (adjusted OR, 0.4; 95% confidence interval [CI], 0.2-0.7). Risk was reduced only for women (adjusted OR, 0.3; 95% CI, 0.1-0.7). PD patients had a decreased risk both for malignant (adjusted OR, 0.6; 95% CI, 0.1-2.5) and nonmalignant neoplasms (adjusted OR, 0.3; 95% CI, 0.1-0.7). Still, risk was decreased for endocrine-related tumors (adjusted OR, 0.3; 95% CI, 0.1-0.9) and non-endocrine-related tumors (adjusted OR, 0.4; 95% CI, 0.1-0.9). Our study confirms the inverse association between PD and neoplasms reported in previous epidemiologic studies.

  14. Endoplasmic reticulum calcium release potentiates the ER stress and cell death caused by an oxidative stress in MCF-7 cells.

    PubMed

    Dejeans, Nicolas; Tajeddine, Nicolas; Beck, Raphaël; Verrax, Julien; Taper, Henryk; Gailly, Philippe; Calderon, Pedro Buc

    2010-05-01

    Increase in cytosolic calcium concentration ([Ca2+](c)), release of endoplasmic reticulum (ER) calcium ([Ca2+](er)) and ER stress have been proposed to be involved in oxidative toxicity. Nevertheless, their relative involvements in the processes leading to cell death are not well defined. In this study, we investigated whether oxidative stress generated during ascorbate-driven menadione redox cycling (Asc/Men) could trigger these three events, and, if so, whether they contributed to Asc/Men cytoxicity in MCF-7 cells. Using microspectrofluorimetry, we demonstrated that Asc/Men-generated oxidative stress was associated with a slow and moderate increase in [Ca2+](c), largely preceding permeation of propidium iodide, and thus cell death. Asc/Men treatment was shown to partially deplete ER calcium stores after 90 min (decrease by 45% compared to control). This event was associated with ER stress activation, as shown by analysis of eIF2 phosphorylation and expression of the molecular chaperone GRP94. Thapsigargin (TG) was then used to study the effect of complete [Ca2+](er) emptying during the oxidative stress generated by Asc/Men. Surprisingly, the combination of TG and Asc/Men increased ER stress to a level considerably higher than that observed for either treatment alone, suggesting that [Ca2+](er) release alone is not sufficient to explain ER stress activation during oxidative stress. Finally, TG-mediated [Ca2+](er) release largely potentiated ER stress, DNA fragmentation and cell death caused by Asc/Men, supporting a role of ER stress in the process of Asc/Men cytotoxicity. Taken together, our results highlight the involvement of ER stress and [Ca2+](er) decrease in the process of oxidative stress-induced cell death in MCF-7 cells.

  15. Calcium intake is not associated with increased coronary artery calcification: The Framingham Study

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Adequate calcium intake is known to protect the skeleton. However, studies that have reported adverse effects of calcium supplementation on vascular events have raised widespread concern. We assessed the association between calcium intake (from diet and supplements) and coronary artery calcification...

  16. [Calcium hypothesis of Alzheimer disease].

    PubMed

    Riazantseva, M A; Mozhaeva, G N; Kaznacheeva, E V

    2012-01-01

    Alzheimer's disease is the most common neurodegenerative disorder characterized by progressive memory and cognitive abilities loss. The etiology of Alzheimer's disease is poorly understood. In this regard, there is no effective treatment for the disease. Various hypotheses to explain the nature of the pathology of Alzheimer's disease led to the development of appropriate therapeutics. Despite of decades of research and clinical trials available therapeutics, at best, can only slow down the progression of the disease, but cannot cure it. This review dedicated to the one of modern hypotheses of Alzheimer's disease pathogenesis implied the impairment of calcium homeostasis as a key event for the development of neurodegenerative processes.

  17. Changes in Cx43 and NaV1.5 expression precede the occurrence of substantial fibrosis in calcineurin-induced murine cardiac hypertrophy.

    PubMed

    Fontes, Magda S C; Raaijmakers, Antonia J A; van Doorn, Tessa; Kok, Bart; Nieuwenhuis, Sylvia; van der Nagel, Roel; Vos, Marc A; de Boer, Teun P; van Rijen, Harold V M; Bierhuizen, Marti F A

    2014-01-01

    In mice, the calcium-dependent phosphatase calcineurin A (CnA) induces a transcriptional pathway leading to pathological cardiac hypertrophy. Interestingly, induction of CnA has been frequently noticed in human hypertrophic and failing hearts. Independently, the arrhythmia vulnerability of such hearts has been regularly associated with remodeling of parameters determining electrical conduction (expression level of connexin43 (Cx43) and NaV1.5, connective tissue architecture), for which the precise molecular basis and sequence of events is still unknown. Recently, we observed reduced Cx43 and NaV1.5 expression in 4-week old mouse hearts, overexpressing a constitutively active form of CnA (MHC-CnA model), but the order of events is still unknown. Therefore, three key parameters of conduction (Cx43, NaV1.5 and connective tissue expression) were characterized in MHC-CnA ventricles versus wild-type (WT) during postnatal development on a weekly basis. At postnatal week 1, CnA overexpression induced cardiac hypertrophy in MHC-CnA. Moreover, protein and RNA levels of both Cx43 and NaV1.5 were reduced by at least 50% as compared to WT. Cx43 immunoreactive signal was reduced at week 2 in MHC-CnA. At postnatal week 3, Cx43 was less phosphorylated and RNA level of Cx43 normalized to WT values, although the protein level was still reduced. Additionally, MHC-CnA hearts displayed substantial fibrosis relative to WT, which was accompanied by increased RNA levels for genes previously associated with fibrosis such as Col1a1, Col1a2, Col3a1, Tgfb1, Ctgf, Timp1 and microRNA miR-21. In MHC-CnA, reduction in Cx43 and NaV1.5 expression thus coincided with overexpression of CnA and hypertrophy development and preceded significant presence of fibrosis. At postnatal week 4 the alterations in conductional parameters observed in the MHC-CnA model lead to abnormal conduction and arrhythmias, similar to those observed in cardiac remodeling in heart failure patients. The MHC-CnA model, therefore

  18. Stretch-activated calcium channels relay fast calcium waves propagated by calcium-induced calcium influx.

    PubMed

    Jaffe, Lionel F

    2007-03-01

    For nearly 30 years, fast calcium waves have been attributed to a regenerative process propagated by CICR (calcium-induced calcium release) from the endoplasmic reticulum. Here, I propose a model containing a new subclass of fast calcium waves which is propagated by CICI (calcium-induced calcium influx) through the plasma membrane. They are called fast CICI waves. These move at the order of 100 to 1000 microm/s (at 20 degrees C), rather than the order of 3 to 30 microm/s found for CICR. Moreover, in this proposed subclass, the calcium influx which drives calcium waves is relayed by stretch-activated calcium channels. This model is based upon reports from approx. 60 various systems. In seven of these reports, calcium waves were imaged, and, in five of these, evidence was presented that these waves were regenerated by CICI. Much of this model involves waves that move along functioning flagella and cilia. In these systems, waves of local calcium influx are thought to cause waves of local contraction by inducing the sliding of dynein or of kinesin past tubulin microtubules. Other cells which are reported to exhibit waves, which move at speeds in the fast CICI range, include ones from a dozen protozoa, three polychaete worms, three molluscs, a bryozoan, two sea urchins, one arthropod, four insects, Amphioxus, frogs, two fish and a vascular plant (Equisetum), together with numerous healthy, as well as cancerous, mammalian cells, including ones from human. In two of these systems, very gentle local mechanical stimulation is reported to initiate waves. In these non-flagellar systems, the calcium influxes are thought to speed the sliding of actinomyosin filaments past each other. Finally, I propose that this mechanochemical model could be tested by seeing if gentle mechanical stimulation induces waves in more of these systems and, more importantly, by imaging the predicted calcium waves in more of them.

  19. Anoxia Precedes the end-Triassic Mass Extinction: Evidence from the Kennecott Point Formation, British Columbia

    NASA Astrophysics Data System (ADS)

    Kasprak, A. H.; Sepúlveda, J.; Price-Waldman, R.; Williford, K. H.; Whiteside, J. H.; Summons, R. E.

    2011-12-01

    The end-Triassic mass extinction (ETE), at 201.4 million years ago, is one of the five largest ecologic disasters of the Phanerozoic eon. Few geologic sections offer the potential to reconstruct environmental and ecological changes at this time in the marine realm with global significance. The Kennecott Point Formation in Haida Gwaii (formerly the Queen Charlotte Islands), British Columbia, preserves a thick sequence of calcareous shales and siltstones deposited on late Triassic basaltic rocks interpreted to be an oceanic plateau resting within the Panthalassic basin, the largest ocean basin at the time of the Triassic-Jurassic transition. This section, which spans the late Norian to the mid-Hettangian, is plausibly the most representative of the global ocean system at this time; however, environmental reconstructions have been mostly based on bulk carbon and sulfur isotope records. Here, we present a record of molecular fossils (biomarkers) and indices indicative of ecological and redox changes (i.e., algal steranes and bacterial hopanes, gammacerane index, homohopane index, 2- and 3- methyl hopane indices) from the Kennecott Point Formation to argue for a period of low oxygen conditions associated with increased stratification, ecological changes, and disrupted nutrient cycling directly preceding the end-Triassic mass extinction. We couple these results with biomarkers indicative of terrestrial input and vegetation disturbance (tricyclic diterpanes and polycyclic aromatic hydrocarbons) to clarify the relationship between ocean biogeochemistry and environmental changes in the terrestrial realm. This record provides new evidence for changing marine conditions preceding and associated with the ETE and allows for a more rigorous investigation into the chronology of events hypothesized to be mechanistically linked to this mass extinction, including abrupt global warming, major alterations to marine primary productivity, and terrestrial vegetation die-off.

  20. Regulation of voltage gated calcium channels by GPCRs and post-translational modification.

    PubMed

    Huang, Junting; Zamponi, Gerald W

    2016-10-18

    Calcium entry via voltage gated calcium channels mediates a wide range of physiological functions, whereas calcium channel dysregulation has been associated with numerous pathophysiological conditions. There are myriad cell signaling pathways that act on voltage gated calcium channels to fine tune their activities and to regulate their cell surface expression. These regulatory mechanisms include the activation of G protein-coupled receptors and downstream phosphorylation events, and their control over calcium channel trafficking through direct physical interactions. Calcium channels also undergo post-translational modifications that alter both function and density of the channels in the plasma membrane. Here we focus on select aspects of these regulatory mechanisms and highlight recent developments.

  1. Store-Operated Calcium Channels.

    PubMed

    Prakriya, Murali; Lewis, Richard S

    2015-10-01

    Store-operated calcium channels (SOCs) are a major pathway for calcium signaling in virtually all metozoan cells and serve a wide variety of functions ranging from gene expression, motility, and secretion to tissue and organ development and the immune response. SOCs are activated by the depletion of Ca(2+) from the endoplasmic reticulum (ER), triggered physiologically through stimulation of a diverse set of surface receptors. Over 15 years after the first characterization of SOCs through electrophysiology, the identification of the STIM proteins as ER Ca(2+) sensors and the Orai proteins as store-operated channels has enabled rapid progress in understanding the unique mechanism of store-operate calcium entry (SOCE). Depletion of Ca(2+) from the ER causes STIM to accumulate at ER-plasma membrane (PM) junctions where it traps and activates Orai channels diffusing in the closely apposed PM. Mutagenesis studies combined with recent structural insights about STIM and Orai proteins are now beginning to reveal the molecular underpinnings of these choreographic events. This review describes the major experimental advances underlying our current understanding of how ER Ca(2+) depletion is coupled to the activation of SOCs. Particular emphasis is placed on the molecular mechanisms of STIM and Orai activation, Orai channel properties, modulation of STIM and Orai function, pharmacological inhibitors of SOCE, and the functions of STIM and Orai in physiology and disease.

  2. Store-Operated Calcium Channels

    PubMed Central

    Lewis, Richard S.

    2015-01-01

    Store-operated calcium channels (SOCs) are a major pathway for calcium signaling in virtually all metozoan cells and serve a wide variety of functions ranging from gene expression, motility, and secretion to tissue and organ development and the immune response. SOCs are activated by the depletion of Ca2+ from the endoplasmic reticulum (ER), triggered physiologically through stimulation of a diverse set of surface receptors. Over 15 years after the first characterization of SOCs through electrophysiology, the identification of the STIM proteins as ER Ca2+ sensors and the Orai proteins as store-operated channels has enabled rapid progress in understanding the unique mechanism of store-operate calcium entry (SOCE). Depletion of Ca2+ from the ER causes STIM to accumulate at ER-plasma membrane (PM) junctions where it traps and activates Orai channels diffusing in the closely apposed PM. Mutagenesis studies combined with recent structural insights about STIM and Orai proteins are now beginning to reveal the molecular underpinnings of these choreographic events. This review describes the major experimental advances underlying our current understanding of how ER Ca2+ depletion is coupled to the activation of SOCs. Particular emphasis is placed on the molecular mechanisms of STIM and Orai activation, Orai channel properties, modulation of STIM and Orai function, pharmacological inhibitors of SOCE, and the functions of STIM and Orai in physiology and disease. PMID:26400989

  3. Extracellular calcium sensing and extracellular calcium signaling

    NASA Technical Reports Server (NTRS)

    Brown, E. M.; MacLeod, R. J.; O'Malley, B. W. (Principal Investigator)

    2001-01-01

    , localized changes in Ca(o)(2+) within the ECF can originate from several mechanisms, including fluxes of calcium ions into or out of cellular or extracellular stores or across epithelium that absorb or secrete Ca(2+). In any event, the CaR and other receptors/sensors for Ca(o)(2+) and probably for other extracellular ions represent versatile regulators of numerous cellular functions and may serve as important therapeutic targets.

  4. Direct Imaging of Hippocampal Epileptiform Calcium Motifs Following Kainic Acid Administration in Freely Behaving Mice

    PubMed Central

    Berdyyeva, Tamara K.; Frady, E. Paxon; Nassi, Jonathan J.; Aluisio, Leah; Cherkas, Yauheniya; Otte, Stephani; Wyatt, Ryan M.; Dugovic, Christine; Ghosh, Kunal K.; Schnitzer, Mark J.; Lovenberg, Timothy; Bonaventure, Pascal

    2016-01-01

    Prolonged exposure to abnormally high calcium concentrations is thought to be a core mechanism underlying hippocampal damage in epileptic patients; however, no prior study has characterized calcium activity during seizures in the live, intact hippocampus. We have directly investigated this possibility by combining whole-brain electroencephalographic (EEG) measurements with microendoscopic calcium imaging of pyramidal cells in the CA1 hippocampal region of freely behaving mice treated with the pro-convulsant kainic acid (KA). We observed that KA administration led to systematic patterns of epileptiform calcium activity: a series of large-scale, intensifying flashes of increased calcium fluorescence concurrent with a cluster of low-amplitude EEG waveforms. This was accompanied by a steady increase in cellular calcium levels (>5 fold increase relative to the baseline), followed by an intense spreading calcium wave characterized by a 218% increase in global mean intensity of calcium fluorescence (n = 8, range [114–349%], p < 10−4; t-test). The wave had no consistent EEG phenotype and occurred before the onset of motor convulsions. Similar changes in calcium activity were also observed in animals treated with 2 different proconvulsant agents, N-methyl-D-aspartate (NMDA) and pentylenetetrazol (PTZ), suggesting the measured changes in calcium dynamics are a signature of seizure activity rather than a KA-specific pathology. Additionally, despite reducing the behavioral severity of KA-induced seizures, the anticonvulsant drug valproate (VA, 300 mg/kg) did not modify the observed abnormalities in calcium dynamics. These results confirm the presence of pathological calcium activity preceding convulsive motor seizures and support calcium as a candidate signaling molecule in a pathway connecting seizures to subsequent cellular damage. Integrating in vivo calcium imaging with traditional assessment of seizures could potentially increase translatability of pharmacological

  5. A monoclonal gammopathy precedes multiple myeloma in most patients

    PubMed Central

    Abadie, Jude; Verma, Pramvir; Howard, Robin S.; Kuehl, W. Michael

    2009-01-01

    Preexisting plasma cell disorders, monoclonal gammopathy of undetermined significance, or smoldering myeloma are present in at least one-third of multiple myeloma patients. However, the proportion of patients with a preexisting plasma cell disorder has never been determined by laboratory testing on prediagnostic sera. We cross-referenced our autologous stem cell transplantation database with the Department of Defense Serum Repository. Serum protein electrophoresis, immunofixation electrophoresis, and serum free light-chain analysis were performed on all sera collected 2 or more years before diagnosis to detect a monoclonal gammopathy (M-Ig). In 30 of 90 patients, 110 prediagnostic samples were available from 2.2 to 15.3 years before diagnosis. An M-Ig was detected initially in 27 of 30 patients (90%, 95% confidence interval, 74%-97%); by serum protein electrophoresis and/or immunofixation electrophoresis in 21 patients (77.8%), and only by serum free light-chain analysis in 6 patients (22.2%). Four patients had only one positive sample within 4 years before diagnosis, with all preceding sera negative. All 4 patients with light-chain/nonsecretory myeloma evolved from a light-chain M-Ig. A preexisting M-Ig is present in most multiple myeloma patients before diagnosis. Some patients progress rapidly through a premalignant phase. Light-chain detected M-Ig is a new entity that requires further study. PMID:19234139

  6. Semantic categorization precedes affective evaluation of visual scenes.

    PubMed

    Nummenmaa, Lauri; Hyönä, Jukka; Calvo, Manuel G

    2010-05-01

    We compared the primacy of affective versus semantic categorization by using forced-choice saccadic and manual response tasks. Participants viewed paired emotional and neutral scenes involving humans or animals flashed rapidly in extrafoveal vision. Participants were instructed to categorize the targets by saccading toward the location occupied by a predefined target scene. The affective task involved saccading toward an unpleasant or pleasant scene, and the semantic task involved saccading toward a scene containing an animal. Both affective and semantic target scenes could be reliably categorized in less than 220 ms, but semantic categorization was always faster than affective categorization. This finding was replicated with singly, foveally presented scenes and manual responses. In comparison with foveal presentation, extrafoveal presentation slowed down the categorization of affective targets more than that of semantic targets. Exposure threshold for accurate categorization was lower for semantic information than for affective information. Superordinate-, basic-, and subordinate-level semantic categorizations were faster than affective evaluation. We conclude that affective analysis of scenes cannot bypass object recognition. Rather, semantic categorization precedes and is required for affective evaluation.

  7. PRECEDENTS FOR AUTHORIZATION OF CONTENTS USING DOSE RATE MEASUREMENTS

    SciTech Connect

    Abramczyk, G.; Bellamy, S.; Nathan, S.; Loftin, B.

    2012-06-05

    For the transportation of Radioactive Material (RAM) packages, the requirements for the maximum allowed dose rate at the package surface and in its vicinity are given in Title 10 of the Code of Federal Regulations, Section 71.47. The regulations are based on the acceptable dose rates to which the public, workers, and the environment may be exposed. As such, the regulations specify dose rates, rather than quantity of radioactive isotopes and require monitoring to confirm the requirements are met. 10CFR71.47 requires that each package of radioactive materials offered for transportation must be designed and prepared for shipment so that under conditions normally incident to transportation the radiation level does not exceed 2 mSv/h (200 mrem/h) at any point on the external Surface of the package, and the transport index does not exceed 10. Before shipment, the dose rate of the package is determined by measurement, ensuring that it conforms to the regulatory limits, regardless of any analyses. This is the requirement for all certified packagings. This paper discusses the requirements for establishing the dose rates when shipping RAM packages and the precedents for meeting these requirements by measurement.

  8. High rates of evolution preceded the origin of birds.

    PubMed

    Puttick, Mark N; Thomas, Gavin H; Benton, Michael J

    2014-05-01

    The origin of birds (Aves) is one of the great evolutionary transitions. Fossils show that many unique morphological features of modern birds, such as feathers, reduction in body size, and the semilunate carpal, long preceded the origin of clade Aves, but some may be unique to Aves, such as relative elongation of the forelimb. We study the evolution of body size and forelimb length across the phylogeny of coelurosaurian theropods and Mesozoic Aves. Using recently developed phylogenetic comparative methods, we find an increase in rates of body size and body size dependent forelimb evolution leading to small body size relative to forelimb length in Paraves, the wider clade comprising Aves and Deinonychosauria. The high evolutionary rates arose primarily from a reduction in body size, as there were no increased rates of forelimb evolution. In line with a recent study, we find evidence that Aves appear to have a unique relationship between body size and forelimb dimensions. Traits associated with Aves evolved before their origin, at high rates, and support the notion that numerous lineages of paravians were experimenting with different modes of flight through the Late Jurassic and Early Cretaceous.

  9. Early Axonopathy Preceding Neurofibrillary Tangles in Mutant Tau Transgenic Mice

    PubMed Central

    Leroy, Karelle; Bretteville, Alexis; Schindowski, Katharina; Gilissen, Emmanuel; Authelet, Michèle; De Decker, Robert; Yilmaz, Zehra; Buée, Luc; Brion, Jean-Pierre

    2007-01-01

    Neurodegenerative diseases characterized by brain and spinal cord involvement often show widespread accumulations of tau aggregates. We have generated a transgenic mouse line (Tg30tau) expressing in the forebrain and the spinal cord a human tau protein bearing two pathogenic mutations (P301S and G272V). These mice developed age-dependent brain and hippocampal atrophy, central and peripheral axonopathy, progressive motor impairment with neurogenic muscle atrophy, and neurofibrillary tangles and had decreased survival. Axonal spheroids and axonal atrophy developed early before neurofibrillary tangles. Neurofibrillary inclusions developed in neurons at 3 months and were of two types, suggestive of a selective vulnerability of neurons to form different types of fibrillary aggregates. A first type of tau-positive neurofibrillary tangles, more abundant in the forebrain, were composed of ribbon-like 19-nm-wide filaments and twisted paired helical filaments. A second type of tau and neurofilament-positive neurofibrillary tangles, more abundant in the spinal cord and the brainstem, were composed of 10-nm-wide neurofilaments and straight 19-nm filaments. Unbiased stereological analysis indicated that total number of pyramidal neurons and density of neurons in the lumbar spinal cord were not reduced up to 12 months in Tg30tau mice. This Tg30tau model thus provides evidence that axonopathy precedes tangle formation and that both lesions can be dissociated from overt neuronal loss in selected brain areas but not from neuronal dysfunction. PMID:17690183

  10. HIGH RATES OF EVOLUTION PRECEDED THE ORIGIN OF BIRDS

    PubMed Central

    Puttick, Mark N; Thomas, Gavin H; Benton, Michael J; Polly, P David

    2014-01-01

    The origin of birds (Aves) is one of the great evolutionary transitions. Fossils show that many unique morphological features of modern birds, such as feathers, reduction in body size, and the semilunate carpal, long preceded the origin of clade Aves, but some may be unique to Aves, such as relative elongation of the forelimb. We study the evolution of body size and forelimb length across the phylogeny of coelurosaurian theropods and Mesozoic Aves. Using recently developed phylogenetic comparative methods, we find an increase in rates of body size and body size dependent forelimb evolution leading to small body size relative to forelimb length in Paraves, the wider clade comprising Aves and Deinonychosauria. The high evolutionary rates arose primarily from a reduction in body size, as there were no increased rates of forelimb evolution. In line with a recent study, we find evidence that Aves appear to have a unique relationship between body size and forelimb dimensions. Traits associated with Aves evolved before their origin, at high rates, and support the notion that numerous lineages of paravians were experimenting with different modes of flight through the Late Jurassic and Early Cretaceous. PMID:24471891

  11. Mancozeb-induced behavioral deficits precede structural neural degeneration.

    PubMed

    Harrison Brody, A; Chou, Eunice; Gray, Janet M; Pokyrwka, Nancy J; Raley-Susman, Kathleen M

    2013-01-01

    Manganese-containing fungicides like Mancozeb have been associated with neurodegenerative conditions like Parkinson's disease. We examined the behavioral damage and differential neuronal vulnerability resulting from Mancozeb exposure using Caenorhabditis elegans, an important mid-trophic level soil organism that is also a powerful model for studying mechanisms of environmental pollutant-induced neurodegenerative disease. The dopamine-mediated swim to crawl locomotory transition behavior is exquisitely vulnerable to Mancozeb, with functional impairment preceding markers of neuronal structural damage. The damage is partially rescued in mutants lacking the divalent metal transporter, SMF-1, demonstrating that some, but not all, of the damage is mediated by manganese. Increasing concentrations of Mancozeb recruit additional behavioral dysfunction, notably serotonin-mediated egg-laying behavior, but without evident serotonergic neuronal structural damage. Thus, measurements of behavioral dysfunction are a sensitive early marker of fungicide toxicity that could be exploited to examine further mechanisms of neuron damage and possible therapeutic interventions. These results also provide important insight into the consequences of fungicide use on the ecological behavior of nematodes.

  12. Activation of ras oncogenes preceding the onset of neoplasia

    SciTech Connect

    Kumar, R.; Barbacid, M. ); Sukumar, S. )

    1990-06-01

    The identification of ras oncogenes in human and animal cancers including precancerous lesions indicates that these genes participate in the early stages of neoplastic development. Yet, these observations do not define the timing of ras oncogene activation in the multistep process of carcinogenesis. To ascertain the timing of ras oncogene activation, an animal model system was devised that involves the induction of mammary carcinomas in rats exposed at birth to the carcinogen nitrosomethylurea. High-resolution restriction fragment length polymorphism analysis of polymerase chain reaction-amplified ras sequences revealed the presence of both H-ras and K-ras oncogenes in normal mammary glands 2 weeks after carcinogen treatment and at least 2 months before the onset of neoplasia. These ras oncogenes can remain latent within the mammary gland until exposure to estrogens, demonstrating that activation of ras oncogenes can precede the onset of neoplasia and suggesting that normal physiological proliferative processes such as estrogen-induced mammary gland development may lead to neoplasia if the targeted cells harbor latent ras oncogenes.

  13. Ultralow-Frequency Magnetic Fields Preceding Large Earthquakes

    NASA Astrophysics Data System (ADS)

    Fraser-Smith, Antony C.

    2008-06-01

    The Great Alaska Earthquake (M 9.2) of 27 March 1964 was the largest earthquake ever to strike the United States in modern times and one of the largest ever recorded anywhere. Later that year, Moore [1964], in a surprisingly rarely cited paper, reported the occurrence of strong ultralow-frequency (ULF; <=10 hertz) magnetic field disturbances at Kodiak, Alaska, in the 1.2 hours before the earthquake. That report has since been followed by others [Fraser-Smith et al., 1990; Kopytenko et al., 1993; Hayakawa et al., 1996; see also Molchanov et al., 1992] similarly describing the occurrence of large-amplitude ULF magnetic field fluctuations before other large earthquakes (``large'' describes earthquakes with magnitudes M ~ 7 or greater). These reports involving four separate, large earthquakes were made by four different groups and the results were published in well-known, refereed scientific journals, so there is no doubt that there is evidence for the existence of comparatively large ULF magnetic field fluctuations preceding large earthquakes.

  14. Bell's palsy: symptoms preceding and accompanying the facial paresis.

    PubMed

    De Seta, Daniele; Mancini, Patrizia; Minni, Antonio; Prosperini, Luca; De Seta, Elio; Attanasio, Giuseppe; Covelli, Edoardo; De Carlo, Andrea; Filipo, Roberto

    2014-01-01

    This individual prospective cohort study aims to report and analyze the symptoms preceding and accompanying the facial paresis in Bell's palsy (BP). Two hundred sixty-nine patients affected by BP with a maximum delay of 48 hours from the onset were enrolled in the study. The evolution of the facial paresis expressed as House-Brackmann grade in the first 10 days and its correlation with symptoms were analyzed. At the onset, 136 patients presented postauricular pain, 114 were affected by dry eye, and 94 reported dysgeusia. Dry mouth was present in 54 patients (19.7%), facial pain, hyperlacrimation, aural fullness, and hyperacusis represented a smaller percentage of the reported symptoms. After 10 days, 39.9% of the group had a severe paresis while 10.2% reached a complete recovery. Dry mouth at the onset was correlated with severe grade of palsy and was prognostic for poor recovery in the early period. These outcomes lead to the deduction that the nervus intermedius plays an important role in the presentation of the BP and it might be responsible for most of the accompanying symptomatology of the paresis. Our findings could be of important interest to early address a BP patient to further examinations and subsequent therapy.

  15. Bell's Palsy: Symptoms Preceding and Accompanying the Facial Paresis

    PubMed Central

    Mancini, Patrizia; Minni, Antonio; Prosperini, Luca; De Seta, Elio; Attanasio, Giuseppe; Covelli, Edoardo; De Carlo, Andrea; Filipo, Roberto

    2014-01-01

    This individual prospective cohort study aims to report and analyze the symptoms preceding and accompanying the facial paresis in Bell's palsy (BP). Two hundred sixty-nine patients affected by BP with a maximum delay of 48 hours from the onset were enrolled in the study. The evolution of the facial paresis expressed as House-Brackmann grade in the first 10 days and its correlation with symptoms were analyzed. At the onset, 136 patients presented postauricular pain, 114 were affected by dry eye, and 94 reported dysgeusia. Dry mouth was present in 54 patients (19.7%), facial pain, hyperlacrimation, aural fullness, and hyperacusis represented a smaller percentage of the reported symptoms. After 10 days, 39.9% of the group had a severe paresis while 10.2% reached a complete recovery. Dry mouth at the onset was correlated with severe grade of palsy and was prognostic for poor recovery in the early period. These outcomes lead to the deduction that the nervus intermedius plays an important role in the presentation of the BP and it might be responsible for most of the accompanying symptomatology of the paresis. Our findings could be of important interest to early address a BP patient to further examinations and subsequent therapy. PMID:25544960

  16. Calcium hydroxide poisoning

    MedlinePlus

    These products contain calcium hydroxide: Cement Limewater Many industrial solvents and cleaners (hundreds to thousands of construction products, flooring strippers, brick cleaners, cement thickening products, and many ...

  17. Calcium: total or ionized?

    PubMed

    Schenck, Patricia A; Chew, Dennis J

    2008-05-01

    Measurement of serum total calcium (tCa) has been relied on for assessment of calcium status, despite the fact that it is the ionized calcium (iCa) fraction that has biologic activity. Serum tCa does not accurately predict iCa status in many clinical conditions. For accurate assessment of iCa status, iCa should be directly measured. Anaerobic measurement of serum iCa under controlled conditions provides the most reliable assessment of calcium status; aerobic measurement of iCa with species-specific pH correction is highly correlated with anaerobic measurements.

  18. Southern Ocean frontal system changes precede Antarctic ice sheet growth during the middle Miocene

    NASA Astrophysics Data System (ADS)

    Kuhnert, Henning; Bickert, Torsten; Paulsen, Harald

    2009-07-01

    The middle Miocene climate approximately 14 Ma ago was characterized by the glaciation of Antarctica, deep-ocean cooling and variations in the global carbon cycle. Although the Southern Ocean underwent significant oceanographic changes, there is limited information on their spatial extent and timing. However, such knowledge is crucial for understanding the role of the Southern Ocean and the Antarctic Circumpolar Current (ACC) for Antarctic glaciation and the coupling between the ocean and continental climate. We have reconstructed surface temperatures and seawater oxygen isotopes at Ocean Drilling Program (ODP) Site 1092 in the Polar Frontal Zone of the Atlantic sector of the Southern Ocean from foraminiferal oxygen isotopes ( δ18O) and magnesium to calcium ratios (Mg/Ca). Sea surface cooling by ~ 4 °C and freshening indicated by the ~ 1‰ reduction of seawater δ18O ( δ18O sw) at 14.2 Ma precede the major step in Antarctic ice sheet growth at 13.8-13.9 Ma. This pattern qualitatively mirrors previous findings from the Pacific sector, and we interpret the surface hydrographic changes to reflect the circum-Antarctic northward shift of the Southern Ocean fronts and specifically at Site 1092 the passage of the Subantarctic Front. The magnitude of change in reconstructed δ18O sw requires a δ18O sw: salinity gradient significantly higher than the modern value (~ 0.52‰) and it possibly exceeded 1.1‰. This implies the Polar Frontal Zone was influenced by freshwater derived from Antarctica, which in turn confirms higher than modern continental precipitation. The latter has previously been suggested to have contributed to Antarctic glaciation.

  19. Combinatorial chemopreventive effect of butyric acid, nicotinamide and calcium glucarate against the 7,12-dimethylbenz(a)anthracene induced mouse skin tumorigenesis attained by enhancing the induction of intrinsic apoptotic events.

    PubMed

    Tiwari, Prakash; Sahay, Satya; Pandey, Manuraj; Qadri, Syed S Y H; Gupta, Krishna P

    2015-01-25

    We explored the basis of the combinatorial chemopreventive effect of butyric acid (BA), nicotinamide (NA) and calcium glucarate (CAG) on mouse skin exposed to 7,12-dimethylbenz(a)anthracene (DMBA). We studied the effects of topical application of DMBA in the presence or absence of BA, NA and CAG on the regulators of apoptosis. DMBA treatment suppressed Bax, Bax/Bcl-2 ratio, release of cyt c, Apaf1, caspase-9, -3 mediated apoptosis. Downregulation of p21 and upregulation of Bcl-2, mut p53 were also observed in only DMBA treated mice. Simultaneous application of BA, NA and CAG induced a mitochondria-mediated apoptosis, characterized by a rise in the Bax, Bax/Bcl-2 ratio, release of cyt c, upregulation of Apaf1 with down-stream activation of caspase-9, -3. Furthermore treatment with BA, NA and CAG demonstrated an upregulation of p21 and downregulation of Bcl-2, mut p53. But this effect was enhanced in the presence of all the three compounds together in combination. Chemoprevention by a combination of BA, NA and CAG by inducing the apoptosis, the natural cell death, suggest the importance of the potential combinational strategies capable of preventing skin tumor development.

  20. Stochastic initiation and termination of calcium-mediated triggered activity in cardiac myocytes

    PubMed Central

    Song, Zhen; Qu, Zhilin; Karma, Alain

    2017-01-01

    Cardiac myocytes normally initiate action potentials in response to a current stimulus that depolarizes the membrane above an excitation threshold. Aberrant excitation can also occur due to spontaneous calcium (Ca2+) release (SCR) from intracellular stores after the end of a preceding action potential. SCR drives the Na+/Ca2+ exchange current inducing a “delayed afterdepolarization” that can in turn trigger an action potential if the excitation threshold is reached. This “triggered activity” is known to cause arrhythmias, but how it is initiated and terminated is not understood. Using computer simulations of a ventricular myocyte model, we show that initiation and termination are inherently random events. We determine the probability of those events from statistical measurements of the number of beats before initiation and before termination, respectively, which follow geometric distributions. Moreover, we elucidate the origin of randomness by a statistical analysis of SCR events, which do not follow a Poisson process observed in other eukaryotic cells. Due to synchronization of Ca2+ releases during the action potential upstroke, waiting times of SCR events after the upstroke are narrowly distributed, whereas SCR amplitudes follow a broad normal distribution with a width determined by fluctuations in the number of independent Ca2+ wave foci. This distribution enables us to compute the probabilities of initiation and termination of bursts of triggered activity that are maintained by a positive feedback between the action potential upstroke and SCR. Our results establish a theoretical framework for interpreting complex and varied manifestations of triggered activity relevant to cardiac arrhythmias. PMID:28049836

  1. Air bubble contact with endothelial cells in vitro induces calcium influx and IP3-dependent release of calcium stores

    PubMed Central

    Sobolewski, Peter; Kandel, Judith; Klinger, Alexandra L.

    2011-01-01

    Gas embolism is a serious complication of decompression events and clinical procedures, but the mechanism of resulting injury remains unclear. Previous work has demonstrated that contact between air microbubbles and endothelial cells causes a rapid intracellular calcium transient and can lead to cell death. Here we examined the mechanism responsible for the calcium rise. Single air microbubbles (50–150 μm), trapped at the tip of a micropipette, were micromanipulated into contact with individual human umbilical vein endothelial cells (HUVECs) loaded with Fluo-4 (a fluorescent calcium indicator). Changes in intracellular calcium were then recorded via epifluorescence microscopy. First, we confirmed that HUVECs rapidly respond to air bubble contact with a calcium transient. Next, we examined the involvement of extracellular calcium influx by conducting experiments in low calcium buffer, which markedly attenuated the response, or by pretreating cells with stretch-activated channel blockers (gadolinium chloride or ruthenium red), which abolished the response. Finally, we tested the role of intracellular calcium release by pretreating cells with an inositol 1,4,5-trisphosphate (IP3) receptor blocker (xestospongin C) or phospholipase C inhibitor (neomycin sulfate), which eliminated the response in 64% and 67% of cases, respectively. Collectively, our results lead us to conclude that air bubble contact with endothelial cells causes an influx of calcium through a stretch-activated channel, such as a transient receptor potential vanilloid family member, triggering the release of calcium from intracellular stores via the IP3 pathway. PMID:21633077

  2. Safety of compounded calcium chloride admixtures for peripheral intravenous administration in the setting of a calcium gluconate shortage.

    PubMed

    Anger, Kevin E; Belisle, Caryn; Colwell, Megan B; Dannemiller, Robert; Alawadhi, Burhan; Wilkocki, Alex; Szumita, Paul M

    2014-10-01

    Calcium gluconate is preferred over calcium chloride for intravenous (IV) repletion of calcium deficiencies in the inpatient setting. In the setting of a national shortage of IV calcium gluconate, our institution implemented a compounded calcium chloride admixture for IV administration. The objective of this analysis is to evaluate the peripheral infusion site safety of compounded IV calcium chloride admixtures in adult inpatients. A total of 222 patients, encompassing 224 inpatient admissions, from April to June 2011 were retrospectively reviewed. Sterile preparations of calcium chloride in 5% dextrose (600 mg/250 mL and 300 mg/100 mL) were used during the study time period. Adverse infusion site reactions were assessed using an institutional infiltration and phlebitis grading system. A total of 333 doses were administered peripherally. In all, 4 (1.8%) patients experienced a moderate to severe infusion site reaction, with 3 due to phlebitis and 1 due to infiltration. Naranjo Nomogram for Adverse Drug Reaction Assessment classified all 4 reactions to have a possible link to calcium chloride administration. Peripheral administration of compounded calcium chloride admixtures in 5% dextrose is associated with a low incidence of IV infusion site reactions and can be considered as an alternative in the event of a calcium gluconate shortage.

  3. Perceived control increases the reward positivity and stimulus preceding negativity.

    PubMed

    Mühlberger, Christina; Angus, Douglas Jozef; Jonas, Eva; Harmon-Jones, Cindy; Harmon-Jones, Eddie

    2017-02-01

    The reward positivity (RewP) and the stimulus preceding negativity (SPN), two ERPs associated with reward delivery and reward anticipation, are modulated by motivational intensity. Motivational intensity is the effort organisms would make to exert behaviors, and it varies with the difficulty of exerting that behavior. If a task is perceived as impossible, which means that one does not have control over own outcomes, motivational intensity is low. In the current study, we tested the prediction that perceiving control over one's outcomes increases both the RewP to feedback and the SPN prior to feedback compared to perceiving no control. We also examined whether P300 and LPP amplitudes to reward and nonreward images were similarly modulated. Twenty-five female participants completed a gambling task in which correct choices were followed by pictures of attractive men and incorrect choices were followed by pictures of rocks. To manipulate perceived control, participants were told that, in one block of trials, they could learn a mouse-click rule in order to see only pictures of men (high perceived control condition), while in the other block, the pictures would appear randomly (low perceived control condition). However, in both conditions, feedback appeared randomly. Although the RewP was elicited in both blocks, the RewP and SPN were higher in the high perceived control condition (i.e., when participants thought that they could influence their outcomes). Perceived control did not modulate the P300 and LPP to pictures. The results suggest that approach motivation and its intensity modulate the processing of performance feedback.

  4. Integrated Vehicle Ground Vibration Testing of Manned Spacecraft: Historical Precedent

    NASA Technical Reports Server (NTRS)

    Lemke, Paul R.; Tuma, Margaret L.; Askins, Bruce R.

    2008-01-01

    For the first time in nearly 30 years, NASA is developing a new manned space flight launch system. The Ares I will carry crew and cargo to not only the International Space Station, but onward for the future exploration of the Moon and Mars. The Ares I control system and structural designs use complex computer models for their development. An Integrated Vehicle Ground Vibration Test (IVGVT) will validate the efficacy of these computer models. The IVGVT will reduce the technical risk of unexpected conditions that could place the vehicle or crew in jeopardy. The Ares Project Office's Flight and Integrated Test Office commissioned a study to determine how historical programs, such as Saturn and Space Shuttle, validated the structural dynamics of an integrated flight vehicle. The study methodology was to examine the historical record and seek out members of the engineering community who recall the development of historic manned launch vehicles. These records and interviews provided insight into the best practices and lessons learned from these historic development programs. The information that was gathered allowed the creation of timelines of the historic development programs. The timelines trace the programs from the development of test articles through test preparation, test operations, and test data reduction efforts. These timelines also demonstrate how the historical tests fit within their overall vehicle development programs. Finally, the study was able to quantify approximate staffing levels during historic development programs. Using this study, the Flight and Integrated Test Office was able to evaluate the Ares I Integrated Vehicle Ground Vibration Test schedule and workforce budgets in light of the historical precedents to determine if the test had schedule or cost risks associated with it.

  5. Podocyte hypertrophy precedes apoptosis under experimental diabetic conditions.

    PubMed

    Lee, Sun Ha; Moon, Sung Jin; Paeng, Jisun; Kang, Hye-Young; Nam, Bo Young; Kim, Seonghun; Kim, Chan Ho; Lee, Mi Jung; Oh, Hyung Jung; Park, Jung Tak; Han, Seung Hyeok; Yoo, Tae-Hyun; Kang, Shin-Wook

    2015-08-01

    Podocyte hypertrophy and apoptosis are two hallmarks of diabetic glomeruli, but the sequence in which these processes occur remains a matter of debate. Here we investigated the effects of inhibiting hypertrophy on apoptosis, and vice versa, in both podocytes and glomeruli, under diabetic conditions. Hypertrophy and apoptosis were inhibited using an epidermal growth factor receptor inhibitor (PKI 166) and a pan-caspase inhibitor (zAsp-DCB), respectively. We observed significant increases in the protein expression of p27, p21, phospho-eukaryotic elongation factor 4E-binding protein 1, and phospho-p70 S6 ribosomal protein kinase, in both cultured podocytes exposed to high-glucose (HG) medium, and streptozotocin-induced diabetes mellitus (DM) rat glomeruli. These increases were significantly inhibited by PKI 166, but not by zAsp-DCB. In addition, the amount of protein per cell, the relative cell size, and the glomerular volume were all significantly increased under diabetic conditions, and these changes were also blocked by treatment with PKI 166, but not zAsp-DCB. Increased protein expression of cleaved caspase-3 and cleaved poly (ADP-ribose) polymerase, together with increased Bax/Bcl-2 ratios, were also observed in HG-stimulated podocytes and DM glomeruli. Treatment with either zAsp-DCB or PKI 166 resulted in a significant attenuation of these effects. Both PKI 166 and zAsp-DCB also inhibited the increase in number of apoptotic cells, as assessed by Hoechst 33342 staining and TUNEL assay. Under diabetic conditions, inhibition of podocyte hypertrophy results in attenuated apoptosis, whereas blocking apoptosis has no effect on podocyte hypertrophy, suggesting that podocyte hypertrophy precedes apoptosis.

  6. Impaired cortical mitochondrial function following TBI precedes behavioral changes

    PubMed Central

    Watson, William D.; Buonora, John E.; Yarnell, Angela M.; Lucky, Jessica J.; D’Acchille, Michaela I.; McMullen, David C.; Boston, Andrew G.; Kuczmarski, Andrew V.; Kean, William S.; Verma, Ajay; Grunberg, Neil E.; Cole, Jeffrey T.

    2014-01-01

    Traumatic brain injury (TBI) pathophysiology can be attributed to either the immediate, primary physical injury, or the delayed, secondary injury which begins minutes to hours after the initial injury and can persist for several months or longer. Because these secondary cascades are delayed and last for a significant time period post-TBI, they are primary research targets for new therapeutics. To investigate changes in mitochondrial function after a brain injury, both the cortical impact site and ipsilateral hippocampus of adult male rats 7 and 17 days after a controlled cortical impact (CCI) injury were examined. State 3, state 4, and uncoupler-stimulated rates of oxygen consumption, respiratory control ratios (RCRs) were measured and membrane potential quantified, and all were significantly decreased in 7 day post-TBI cortical mitochondria. By contrast, hippocampal mitochondria at 7 days showed only non-significant decreases in rates of oxygen consumption and membrane potential. NADH oxidase activities measured in disrupted mitochondria were normal in both injured cortex and hippocampus at 7 days post-CCI. Respiratory and phosphorylation capacities at 17 days post-CCI were comparable to naïve animals for both cortical and hippocampus mitochondria. However, unlike oxidative phosphorylation, membrane potential of mitochondria in the cortical lining of the impact site did not recover at 17 days, suggesting that while diminished cortical membrane potential at 17 days does not adversely affect mitochondrial capacity to synthesize ATP, it may negatively impact other membrane potential-sensitive mitochondrial functions. Memory status, as assessed by a passive avoidance paradigm, was not significantly impaired until 17 days after injury. These results indicate pronounced disturbances in cortical mitochondrial function 7 days after CCI which precede the behavioral impairment observed at 17 days. PMID:24550822

  7. Pregnancy and employment leave: legal precedents and future policy.

    PubMed

    Gardin, S K; Richwald, G A

    1986-01-01

    An estimated 85% of female workers in the US become pregnant during their working lives; 62% of married US women were employed for some period during the 12 months preceding childbirth. Historically, US legislation has assumed a protectionist policy with regard to restricting prenatal and postpartum employment, yet this stance has not been backed up by protection of income, benefits, reinstatement, or seniority. The passage in 1964 of Title VII of the Federal Civil Rights Act banning discrimination on the basis of sex triggered a long string of legal battles fought on the premise that pregnancy is a disability. As a result of Congressional efforts, an amendment to Title VII--the Pregnancy Discrimination Act--was passed in 1978. This law requires that women disabled due to pregnancy or childbirth be provided with the same benefits as those provided other disabled employees. However, the law does not require an employer who does not provide disability benefits, paid sick leave, or medical benefits to other employees to provide them to pregnant women. A weakness of existing legislation is its failure to address the difficulties inherent in accommodating childbearing women in the labor force. Accommodation under the current employment system results in productivity disruption and financial losses for both employer and employee. In all other major industrial countries, maternity benefits such as paid leave before and after childbirth, reinstatement rights, and nursing breaks on the job are guaranteed through national legislation. Such benefits emanate from acknowledgment of women's essential participation in the labor force as well as their unique ability to give birth. Under a more flexible employment system, equal protection would not result in the denial of maternity leave to female employees, but rather the provision parental leave to male and female employees.

  8. Predictability of rogue events.

    PubMed

    Birkholz, Simon; Brée, Carsten; Demircan, Ayhan; Steinmeyer, Günter

    2015-05-29

    Using experimental data from three different rogue wave supporting systems, determinism, and predictability of the underlying dynamics are evaluated with methods of nonlinear time series analysis. We included original records from the Draupner platform in the North Sea as well as time series from two optical systems in our analysis. One of the latter was measured in the infrared tail of optical fiber supercontinua, the other in the fluence profiles of multifilaments. All three data sets exhibit extreme-value statistics and exceed the significant wave height in the respective system by a factor larger than 2. Nonlinear time series analysis indicates a different degree of determinism in the systems. The optical fiber scenario is found to be driven by quantum noise whereas rogue waves emerge as a consequence of turbulence in the others. With the large number of rogue events observed in the multifilament system, we can systematically explore the predictability of such events in a turbulent system. We observe that rogue events do not necessarily appear without a warning, but are often preceded by a short phase of relative order. This surprising finding sheds some new light on the fascinating phenomenon of rogue waves.

  9. Calcium fluoride window mounting

    NASA Astrophysics Data System (ADS)

    Berger, D. Douglas

    1982-10-01

    A technique has been developed for joining a large calcium fluoride crystal to a stainless-steel flange by means of a silver transition ring. The process involves both vacuum brazing using a copper-silver alloy and air brazing using silver chloride. This paper describes the procedure used in fabricating a high-vacuum leak-tight calcium fluoride window assembly.

  10. Calcium and bones (image)

    MedlinePlus

    ... for the growth, maintenance, and reproduction of the human body. Bones, like other tissues in the body, are continually being re-formed and incorporate calcium into their structure. Calcium is essential for the formation of and maintenance of healthy teeth.

  11. 48 CFR 411.101 - Order of precedence for requirements documents.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... AGRICULTURE COMPETITION AND ACQUISITION PLANNING DESCRIBING AGENCY NEEDS Selecting and Developing Requirements Documents 411.101 Order of precedence for requirements documents. (a) Office of Management and Budget...

  12. Kidney and calcium homeostasis.

    PubMed

    Jeon, Un Sil

    2008-12-01

    Plasma calcium concentration is maintained within a narrow range (8.5-10.5 mg/dL) by the coordinated action of parathyroid hormone (PTH), 1,25(OH)2D3, calcitonin, and ionized calcium (iCa(2+)) itself. The kidney plays a key role in this process by the fine regulation of calcium excretion. More than 95% of filtered calcium is reabsorbed along the renal tubules. In the proximal tubules, 60% of filtered calcium is reabsorbed by passive mechanisms. In the thick ascending limb, 15% of calcium is reabsorbed by paracellular diffusion through paracellin-1 (claudin-16). The calcium sensing receptor (CaSR) in the basolateral membrane of the thick ascending limb senses the change in iCa(2+) and inhibits calcium reabsorption independent to PTH and 1,25(OH)2D3. The fine regulation of calcium excretion occurs in the distal convoluted tubules and connecting tubules despite the fact that only 10-15% of filtered calcium is reabsorbed there. Transient receptor potential vanilloid 5 (TRPV5) and 6 (TRPV6) in the apical membrane act as the main portal of entry, calbindin-D28K delivers Ca(2+) in the cytoplasm, and then Na(2+)/Ca(2+) exchanger (NCX1) and plasma membrane Ca(2+)-ATPase in the basolateral membrane serve as an exit. In the cortical collecting duct, TRPV6 is expressed, but the role might be negligible. In addition to PTH and 1,25(OH)2D3, acid-base disturbance, diuretics, and estrogen affect on these calcium channels. Recently, klotho and fibroblast growth factor 23 (FGF23) are suggested as new players in the calcium metabolism. Klotho is exclusively expressed in the kidney and co-localized with TRPV5, NCX1, and calbindin-D28K. Klotho increases calcium reabsorption through trafficking of TRPV5 to the plasma membrane, and also converts FGF receptor to the specific FGF23 receptor. FGF23:klotho complex bound to FGF receptor inhibits 1α-hydroxylase of vitamin D, and contributes to calcium reabsorption and phosphate excretion in the kidney.

  13. Etiquette and Protocol: A Guide for Campus Events.

    ERIC Educational Resources Information Center

    Harris, April L.

    Intended for special events planners on college campuses, this book offers advice on matters of etiquette and protocol for campus events. Chapters cover the following topics: (1) invitations (e.g., the precedence of extending invitations, invitation components, formal invitations, types of invitations); (2) forms of address (with examples of…

  14. Calcium pathway machinery at fertilization in echinoderms.

    PubMed

    Ramos, Isabela; Wessel, Gary M

    2013-01-01

    Calcium signaling in cells directs diverse physiological processes. The calcium waves triggered by fertilization is a highly conserved calcium signaling event essential for egg activation, and has been documented in every egg tested. This activity is one of the few highly conserved events of egg activation through the course of evolution. Echinoderm eggs, as well as many other cell types, have three main intracellular Ca(2+) mobilizing messengers - IP3, cADPR and NAADP. Both cADPR and NAADP were identified as Ca(2+) mobilizing messengers using the sea urchin egg homogenate, and this experimental system, along with the intact urchin and starfish oocyte/egg, continues to be a vital tool for investigating the mechanism of action of calcium signals. While many of the major regulatory steps of the IP3 pathway are well resolved, both cADPR and NAADP remain understudied in terms of our understanding of the fundamental process of egg activation at fertilization. Recently, NAADP has been shown to trigger Ca(2+) release from acidic vesicles, separately from the ER, and a new class of calcium channels, the two-pore channels (TPCs), was identified as the likely targets for this messenger. Moreover, it was found that both cADPR and NAADP can be synthesized by the same family of enzymes, the ADP-rybosyl cyclases (ARCs). In this context of increasing amount of information, the potential coupling and functional roles of different messengers, intracellular stores and channels in the formation of the fertilization calcium wave in echinoderms will be critically evaluated.

  15. Rising catch variability preceded historical fisheries collapses in Alaska.

    PubMed

    Litzow, Michael A; Mueter, Franz J; Urban, J Daniel

    2013-09-01

    Statistical indicators such as rising variance and rising skewness in key system parameters may provide early warning of "regime shifts" in communities and populations. However, the utility of these indicators has rarely been tested in the large, complex ecosystems that are of most interest to managers. Crustacean fisheries in the Gulf of Alaska and Bering Sea experienced a series of collapses beginning in the 1970s, and we used spatially resolved catch data from these fisheries to test the predictions that increasing variability and skewness would precede stock collapse. Our data set consisted of catch data from 14 fisheries (12 collapsing and two non-collapsing), spanning 278 cumulative years. Our sampling unit for analysis was the Alaska Department of Fish and Game statistical reporting area (mean n for individual fisheries = 42 areas, range 7-81). We found that spatial variability in catches increased prior to stock collapse: a random-effects model estimating trend in variability across all 12 collapsing fisheries showed strong evidence of increasing variability prior to collapse. Individual trends in variability were statistically significant for only four of the 12 collapsing fisheries, suggesting that rising variability might be most effective as an indicator when information from multiple populations is available. Analyzing data across multiple fisheries allowed us to detect increasing variability 1-4 years prior to collapse, and trends in variability were significantly different for collapsing and non-collapsing fisheries. In spite of theoretical expectations, we found no evidence of pre-collapse increases in catch skewness. Further, while models generally predict that rising variability should be a transient phenomenon around collapse points, increased variability was a persistent feature of collapsed fisheries in our study. We conclude that this result is more consistent with fishing effects as the cause of increased catch variability, rather than the

  16. Unifying principles of calcium wave propagation - Insights from a three-dimensional model for atrial myocytes.

    PubMed

    Thul, R; Rietdorf, K; Bootman, M D; Coombes, S

    2015-09-01

    Atrial myocytes in a number of species lack transverse tubules. As a consequence the intracellular calcium signals occurring during each heartbeat exhibit complex spatio-temporal dynamics. These calcium patterns arise from saltatory calcium waves that propagate via successive rounds of diffusion and calcium-induced calcium release. The many parameters that impinge on calcium-induced calcium release and calcium signal propagation make it difficult to know a priori whether calcium waves will successfully travel, or be extinguished. In this study, we describe in detail a mathematical model of calcium signalling that allows the effect of such parameters to be independently assessed. A key aspect of the model is to follow the triggering and evolution of calcium signals within a realistic three-dimensional cellular volume of an atrial myocyte, but with low computational costs. This is achieved by solving the linear transport equation for calcium analytically between calcium release events and by expressing the onset of calcium liberation as a threshold process. The model makes non-intuitive predictions about calcium signal propagation. For example, our modelling illustrates that the boundary of a cell produces a wave-guiding effect that enables calcium ions to propagate further and for longer, and can subtly alter the pattern of calcium wave movement. The high spatial resolution of the modelling framework allows the study of any arrangement of calcium release sites. We demonstrate that even small variations in randomly positioned release sites cause highly heterogeneous cellular responses. This article is part of a Special Issue entitled: 13th European Symposium on Calcium.

  17. Strong and Anomalous Thermal Expansion Precedes the Thermosalient Effect in Dynamic Molecular Crystals

    NASA Astrophysics Data System (ADS)

    Panda, Manas K.; Centore, Roberto; Causà, Mauro; Tuzi, Angela; Borbone, Fabio; Naumov, Panče

    2016-07-01

    The ability of thermosalient solids, organic analogues of inorganic martensites, to move by rapid mechanical reconfiguration or ballistic event remains visually appealing and potentially useful, yet mechanistically elusive phenomenon. Here, with a material that undergoes both thermosalient and non-thermosalient phase transitions, we demonstrate that the thermosalient effect is preceded by anomalous thermal expansion of the unit cell. The crystal explosion occurs as sudden release of the latent strain accumulated during the anisotropic, exceedingly strong expansion of the unit cell with αa = 225.9 × 10‑6 K‑1, αb = 238.8 × 10‑6 K‑1 and αc = ‑290.0 × 10‑6 K‑1, the latter being the largest negative thermal expansivity observed for an organic compound thus far. The results point out to the occurence of the thermosalient effect in phase transitions as means to identify new molecular materials with strong positive and/or negative thermal expansion which prior to this work could only be discovered serendipitously.

  18. Strong and Anomalous Thermal Expansion Precedes the Thermosalient Effect in Dynamic Molecular Crystals.

    PubMed

    Panda, Manas K; Centore, Roberto; Causà, Mauro; Tuzi, Angela; Borbone, Fabio; Naumov, Panče

    2016-07-12

    The ability of thermosalient solids, organic analogues of inorganic martensites, to move by rapid mechanical reconfiguration or ballistic event remains visually appealing and potentially useful, yet mechanistically elusive phenomenon. Here, with a material that undergoes both thermosalient and non-thermosalient phase transitions, we demonstrate that the thermosalient effect is preceded by anomalous thermal expansion of the unit cell. The crystal explosion occurs as sudden release of the latent strain accumulated during the anisotropic, exceedingly strong expansion of the unit cell with αa = 225.9 × 10(-6) K(-1), αb = 238.8 × 10(-6) K(-1) and αc = -290.0 × 10(-6) K(-1), the latter being the largest negative thermal expansivity observed for an organic compound thus far. The results point out to the occurence of the thermosalient effect in phase transitions as means to identify new molecular materials with strong positive and/or negative thermal expansion which prior to this work could only be discovered serendipitously.

  19. Sumoylation precedes accumulation of phosphorylated H2AX on sex chromosomes during their meiotic inactivation.

    PubMed

    Vigodner, Margarita

    2009-01-01

    During meiosis in male mammals, X and Y chromosomes undergo the process of meiotic sex chromosome inactivation (MSCI). A crucial role in MSCI has recently been reported for BRCA1, ATR kinase, and phosphorylated histone H2AX, but the exact mechanism remains to be determined. Small ubiquitin-like modifier (SUMO) proteins have recently been shown to localize to the sex body in mouse meiotic spermatocytes, but the role they play during MSCI is unknown. In this study, in order to better understand the molecular events of MSCI, we followed dynamic changes in gammaH2AX and SUMO localization patterns during MSCI. Using confocal laser scanning microscopy (CLSM) as an analytical tool for visualizing numerous spermatocytes from the same development stage and for consecutively following the meiotic progression, we were able to demonstrate a very early appearance of SUMO-1, which preceded gammaH2AX accumulation on the sex chromosomes during their meiotic inactivation. In contrast to SUMO-1, SUMO-2/3 was undetectable in zygotene spermatocytes, suggesting a possible specific role for SUMO-1 in the initiation of MSCI.

  20. Strong and Anomalous Thermal Expansion Precedes the Thermosalient Effect in Dynamic Molecular Crystals

    PubMed Central

    Panda, Manas K.; Centore, Roberto; Causà, Mauro; Tuzi, Angela; Borbone, Fabio; Naumov, Panče

    2016-01-01

    The ability of thermosalient solids, organic analogues of inorganic martensites, to move by rapid mechanical reconfiguration or ballistic event remains visually appealing and potentially useful, yet mechanistically elusive phenomenon. Here, with a material that undergoes both thermosalient and non-thermosalient phase transitions, we demonstrate that the thermosalient effect is preceded by anomalous thermal expansion of the unit cell. The crystal explosion occurs as sudden release of the latent strain accumulated during the anisotropic, exceedingly strong expansion of the unit cell with αa = 225.9 × 10−6 K−1, αb = 238.8 × 10−6 K−1 and αc = −290.0 × 10−6 K−1, the latter being the largest negative thermal expansivity observed for an organic compound thus far. The results point out to the occurence of the thermosalient effect in phase transitions as means to identify new molecular materials with strong positive and/or negative thermal expansion which prior to this work could only be discovered serendipitously. PMID:27403616

  1. The influence of preceding dive cycles on the foraging decisions of Antarctic fur seals

    PubMed Central

    Iwata, T.; Sakamoto, K. Q.; Edwards, E. W. J.; Staniland, I. J.; Trathan, P. N.; Goto, Y.; Sato, K.; Naito, Y.; Takahashi, A.

    2015-01-01

    The foraging strategy of many animals is thought to be determined by their past experiences. However, few empirical studies have investigated whether this is true in diving animals. We recorded three-dimensional movements and mouth-opening events from three Antarctic fur seals during their foraging trips to examine how they adapt their behaviour based on past experience—continuing to search for prey in the same area or moving to search in a different place. Each dive cycle was divided into a transit phase and a feeding phase. The linear horizontal distance travelled after feeding phases in each dive was affected by the mouth-opening rate during the previous 244 s, which typically covered two to three dive cycles. The linear distance travelled tended to be shorter when the mouth-opening rate in the previous 244 s was higher, i.e. seals tended to stay in the same areas with high prey-encounter rates. These results indicate that Antarctic fur seals follow decision-making strategies based on the past foraging experience over time periods longer than the immediately preceding dive. PMID:26156132

  2. DNA damage precedes apoptosis during the regression of the interdigital tissue in vertebrate embryos

    PubMed Central

    Montero, Juan A.; Sanchez-Fernandez, Cristina; Lorda-Diez, Carlos I.; Garcia-Porrero, Juan A.; Hurle, Juan M.

    2016-01-01

    DNA damage independent of caspase activation accompanies programmed cell death in different vertebrate embryonic organs. We analyzed the significance of DNA damage during the regression of the interdigital tissue, which sculpts the digits in the embryonic limb. Interdigit remodeling involves oxidative stress, massive apoptosis and cell senescence. Phosphorylation of H2AX mediated by ATM precedes caspase dependent apoptosis and cell senescence during interdigit regression. The association of γH2AX with other downstream DNA repair factors, including MDC1, Rad50 and 53BP1 suggests a defensive response of cells against DNA damage. The relative distribution of cells γH2AX-only positive, TUNEL-only positive, and cells double positive for both markers is consistent with a sequence of degenerative events starting by damage of the DNA. In support of this interpretation, the relative number of γH2AX-only cells increases after caspase inhibition while the relative number of TUNEL-only cells increases after inhibition of ATM. Furthermore, cultured interdigits survived and maintained intense chondrogenic potential, even at advanced stages of degeneration, discarding a previous commitment to die. Our findings support a new biological paradigm considering embryonic cell death secondary to genotoxic stimuli, challenging the idea that considers physiological cell death a cell suicide regulated by an internal death clock that pre-programmes degeneration. PMID:27752097

  3. Subcellular localization of calcium deposits during zebrafish (Danio rerio) oogenesis.

    PubMed

    Golpour, Amin; Pšenička, Martin; Niksirat, Hamid

    2016-01-01

    Calcium plays prominent roles in regulating a broad range of physiological events in reproduction. The aim of this study was to describe the subcellular distribution of calcium deposits during stages of oogenesis in zebrafish using a combined oxalate-pyroantimonate technique. The oocyte development of zebrafish was categorized into four stages: primary growth, cortical-alveolus, vitellogenic, and maturation, based on morphological criteria. Calcium deposits in the primary growth stage were detected in the cytoplasm, mitochondria, nucleus, and follicular cells. At the cortical-alveolus stage, calcium particles were transported from follicular cells and deposited in the cortical alveoli. In the vitellogenic stage, some cortical alveoli were compacted and transformed from flocculent electron-lucent to electron-dense objects with the progression of the stage. Calcium deposits were transformed from larger to smaller particles, coinciding with compaction of cortical alveoli. In the maturation stage, calcium deposits in all oocyte compartments decreased, with the exception of those in mitochondria. The proportion of area covered by calcium deposits in the mitochondria and cortical alveoli of oocytes at different stages of development was significantly different (p<0.05). The extent of calcium deposits in the cortical alveoli of mature oocytes was substantially lower than in earlier stages. Basic information about calcium distribution during zebrafish oogenesis may contribute to better understanding of its role in oogenesis.

  4. Calcium antagonists and atherosclerosis protection in hypertension.

    PubMed

    Hernández, Rafael Hernández; Armas-Hernández, María José; Velasco, Manuel; Israili, Zafar H; Armas-Padilla, María Cristina

    2003-01-01

    Calcium antagonists are effective in hypertensive patients of all ethnic groups, irrespective of age, dietary salt intake, salt-sensitivity status or plasma renin activity profile. Some prospective studies show that the calcium antagonists, nifedipine GITS and nitrendipine, reduce cardiovascular morbidity and mortality at least to the same extent as the diuretics. Other prospective studies are in progress to evaluate the effect of calcium antagonists on cardiovascular morbidity and mortality, and the progression of atherosclerosis in hypertensive patients. Calcium antagonists, especially the highly lipophilic amlodipine, lacidipine and nisoldipine, are shown to possess antioxidant properties. These drugs reduce the oxidation of LDL and its influx into the arterial wall, and reduce atherosclerotic lesions in animals. Platelet production of malondialdehyde, a marker of oxygen free radical formation, is suppressed by amlodipine, lacidipine or nifedipine in hypertensive patients. New evidence from long-term clinical trials of calcium antagonists indicates that these drugs can reduce the rate of progression of atherosclerosis in hypertensive and coronary heart disease patients. In the Regression Growth Evaluation Statin Study (REGRESS), co-administration of calcium antagonist, amlodipine or nifedipine with pravasatin caused a significant reduction in the appearance of new angiographic lesions. In the Verapamil in Hypertension and Atherosclerosis Study (VHAS), verapamil was more effective than chlorthalidone in promoting regression of thicker carotid lesions in parallel with a reduction in the incidence of cardiovascular events. In the Prospective Randomized Evaluation of the Vascular Effects of Norvasc Trial (PREVENT), amlodipine slowed the progression of early coronary atherosclerosis in patients with coronary artery disease. In a subprotocol of the Intervention as a Goal in the Hypertension Treatment (INSIGHT) study, nifedipine GITS significantly decreased intima

  5. [Calcium and health].

    PubMed

    Ortega Anta, Rosa M; Jiménez Ortega, Ana I; López-Sobaler, Ana M

    2015-04-07

    An adequate intake of calcium is only not limited to avoid the risk of osteoporosis and its benefits in longterm bone health, but also it has been linked to protection against various major diseases, such as hypertension, cancer, kidney stones, insulin resistance, diabetes... and several investigations suggest its importance in preventing and controlling obesity. Studies conducted in Spanish representative samples show that a high percentage of adults and children (> 75%) don't achieve the recommended intake of calcium. Moreover, are growing trends among the population suggesting that calcium intake and dairy consumption (main food source of the mineral) are high, and even excessive, in many individuals. This misconception results in that the calcium intake is increasingly far from the recommended one. The maximum tolerable intake of the mineral is fixed at 2.500 mg/day, but this intake is unusual, and it's more disturbing and frequent, to find intakes below the recommended calcium intakes (1.000 and 1.200 mg/day in adults, men and women, respectively). Data from different studies highlight the risk of an inadequate calcium intake and the damages that may affect the health in a long term. It is not about transmitting indiscriminate guidelines in order to increase the intake of calcium / dairy, but the recommended intakes must be met to achieve both the nutritional and health benefits. Also activities for demystification of misconceptions are need, increasingly frequent, that may impair health population.

  6. Calcium Signaling and Neurodegeneration

    PubMed Central

    2010-01-01

    Neurodegenerative disorders, such as Alzheimer’s disease (AD), Parkinson’s disease (PD), amyotrophic lateral sclerosis (ALS), Huntington’s disease (HD), and spinocerebellar ataxias (SCA) are very important both for fundamental science and for practical medicine. Despite extensive research into the causes of these diseases, clinical researchers have had very limited progress and, as of now, there is still no cure for any of these diseases. One of the main obstacles in the way of creating treatments for these disorders is the fact that their etiology and pathophysiology still remain unclear. This paper reviews results that support the so–called “calcium hypothesis of neurodegenerative diseases.” The calcium hypothesis states that the atrophic and degenerative processes in the neurons of AD, PD, ALS, HD, and SCA patients are accompanied by alterations in calcium homeostasis. Moreover, the calcium hypothesis states that this deregulation of calcium signaling is one of the early–stage and key processes in the pathogenesis of these diseases. Based on the results we reviewed, we conclude that the calcium channels and other proteins involved in the neuronal calcium signaling system are potential drug targets for AD, PD, ALS, HD, and SCA therapy. PMID:22649630

  7. Macrophages engulf endothelial cell membrane particles preceding pupillary membrane capillary regression.

    PubMed

    Poché, Ross A; Hsu, Chih-Wei; McElwee, Melissa L; Burns, Alan R; Dickinson, Mary E

    2015-07-01

    Programmed capillary regression and remodeling are essential developmental processes. However, the cellular and molecular mechanisms that regulate vessel regression are only the beginning to be understood. Here, using in vivo, dynamic, confocal imaging of mouse transgenic reporters as well as static confocal and electron microscopy, we studied the embryonic development and postnatal regression of the transient mouse pupillary membrane (PM) vasculature. This approach allowed us to directly observe the precise temporal sequence of cellular events preceding and during the elimination of the PM from the mouse eye. Imaging of Tcf/Lef-H2B::GFP Wnt-reporter mice uncovered that, unlike the hyaloid vasculature of the posterior eye, a PM endothelial cell (EC) Wnt/β-catenin response is unlikely to be part of the regression mechanism. Live imaging of EC and macrophage dynamics revealed highly active Csf1r-GFP+ macrophages making direct contact with the Flk1-myr::mCherry+ vessel surface and with membrane protrusions or filopodia extending from the ECs. Flk1-myr::mCherry+ EC membrane particles were observed on and around ECs as well as within macrophages. Electron microscopy studies confirmed that they were in phagosomes within macrophages, indicating that the macrophages engulfed the membrane particles. Interestingly, EC plasma membrane uptake by PM macrophages did not correlate with apoptosis and was found shortly after vessel formation at mid-gestation stages in the embryo; long before vessel regression begins during postnatal development. Additionally, genetic ablation of macrophages showed that EC membrane particles were still shed in the absence of macrophages suggesting that macrophages do not induce the formation or release of EC microparticles. These studies have uncovered a novel event during programmed capillary regression in which resident macrophages scavenge endothelial cell microparticles released from the PM vessels. This finding suggests that there may be an

  8. Ethanol-induced oxidative stress precedes mitochondrially mediated apoptotic death of cultured fetal cortical neurons.

    PubMed

    Ramachandran, Vinitha; Watts, Lora Talley; Maffi, Shivani Kaushal; Chen, Juanjuan; Schenker, Steven; Henderson, George

    2003-11-15

    In utero ethanol exposure elicits apoptotic cell death in the fetal brain, and this may be mediated by oxidative stress. Our studies utilize cultured fetal rat cortical neurons and illustrate that ethanol elicits a rapid onset of oxidative stress, which culminates in mitochondrially mediated apoptotic cell death. Cells exposed to ethanol (2.5 mg/ml) remained attached to their polylysine matrix during a 24-hr exposure, but they exhibited distinct signs of oxidative stress, decreased viability, and apoptosis. Confocal microscopy of live cortical neurons pretreated with dichlorodihydrofluorescein diacetate demonstrated an increase in reactive oxygen species (ROS) within 5 min of ethanol exposure. The levels of ROS further increased by 58% within 1 hr (P <.05) and by 82% within 2 hr (P <.05), accompanied by increases of mitochondrial 4-hydroxynonenal (HNE). These early events were followed by decreased trypan blue exclusion of 10% to 32% (P <.05) at the 6- to 24-hr time points, respectively. This culminates in apoptotic death, with increases of Annexin V binding of 43%, 89%, 123%, and 238%, at 2, 6, 12, and 24 hr of ethanol treatment, respectively, as well as DNA fragmentation increases of 50% and 65% by 12 and 24 hr, respectively. Release of cytochrome c by mitochondria increased by 53% at 6 hr of exposure (P <.05), concomitant with activation of caspase 3 (52% at 12 hr, P <.05). Pretreatment with N-acetylcysteine increased cellular glutathione and prevented apoptosis. These studies provide a time line illustrating that oxidative stress and formation of a proapoptotic lipid peroxidation product, HNE, precede a cascade of mitochondrially mediated events in cultured fetal cortical neurons, culminating in apoptotic death. The prevention of apoptosis by augmentation of glutathione stores also strongly supports a role for oxidative stress in ethanol-mediated apoptotic death of fetal cortical neurons.

  9. Event Perception.

    PubMed

    Radvansky, Gabriel; Zacks, Jeffrey M

    2011-11-01

    Events are central elements of human experience. Formally, they can be individuated in terms of the entities that compose them, the features of those entities, and the relations amongst entities. Psychologically, representations of events capture their spatiotemporal location, the people and objects involved, and the relations between these elements. Here, we present an account of the nature of psychological representations of events and how they are constructed and updated. Event representations are like images in that they are isomorphic to the situations they represent. However, they are like models or language in that they are constructed of components rather than being holistic. Also, they are partial representations that leave out some elements and abstract others. Representations of individual events are informed by schematic knowledge about general classes of events. Event representations are constructed in a process that segments continuous activity into discrete events. The construction of a series of event representations forms a basis for predicting the future, planning for that future, and imagining alternatives.

  10. Event Perception

    PubMed Central

    Radvansky, Gabriel; Zacks, Jeffrey M.

    2012-01-01

    Events are central elements of human experience. Formally, they can be individuated in terms of the entities that compose them, the features of those entities, and the relations amongst entities. Psychologically, representations of events capture their spatiotemporal location, the people and objects involved, and the relations between these elements. Here, we present an account of the nature of psychological representations of events and how they are constructed and updated. Event representations are like images in that they are isomorphic to the situations they represent. However, they are like models or language in that they are constructed of components rather than being holistic. Also, they are partial representations that leave out some elements and abstract others. Representations of individual events are informed by schematic knowledge about general classes of events. Event representations are constructed in a process that segments continuous activity into discrete events. The construction of a series of event representations forms a basis for predicting the future, planning for that future, and imagining alternatives. PMID:23082236

  11. 21 CFR 184.1191 - Calcium carbonate.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... soda process”; (2) By precipitation of calcium carbonate from calcium hydroxide in the “Carbonation process”; or (3) By precipitation of calcium carbonate from calcium chloride in the “Calcium...

  12. 21 CFR 184.1191 - Calcium carbonate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... soda process”; (2) By precipitation of calcium carbonate from calcium hydroxide in the “Carbonation process”; or (3) By precipitation of calcium carbonate from calcium chloride in the “Calcium...

  13. 21 CFR 184.1191 - Calcium carbonate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... soda process”; (2) By precipitation of calcium carbonate from calcium hydroxide in the “Carbonation process”; or (3) By precipitation of calcium carbonate from calcium chloride in the “Calcium...

  14. 21 CFR 184.1191 - Calcium carbonate.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... soda process”; (2) By precipitation of calcium carbonate from calcium hydroxide in the “Carbonation process”; or (3) By precipitation of calcium carbonate from calcium chloride in the “Calcium...

  15. CALCIUM CHLORIDE PLANT LOOKING EAST. CALCIUM CHLORIDE BUILDING ON LEFT, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    CALCIUM CHLORIDE PLANT LOOKING EAST. CALCIUM CHLORIDE BUILDING ON LEFT, CALCIUM CHLORIDE STORAGE BUILDING ON RIGHT OF CENTER WITH TOP OF SA (SODA ASH) BUILDING IN RIGHT BACKGROUND. - Solvay Process Company, Calcium Chloride Plant, Between Willis & Milton Avenues, Solvay, Onondaga County, NY

  16. A synthesis of radial growth patterns preceding tree mortality.

    PubMed

    Cailleret, Maxime; Jansen, Steven; Robert, Elisabeth M R; Desoto, Lucía; Aakala, Tuomas; Antos, Joseph A; Beikircher, Barbara; Bigler, Christof; Bugmann, Harald; Caccianiga, Marco; Čada, Vojtěch; Camarero, Jesus J; Cherubini, Paolo; Cochard, Hervé; Coyea, Marie R; Čufar, Katarina; Das, Adrian J; Davi, Hendrik; Delzon, Sylvain; Dorman, Michael; Gea-Izquierdo, Guillermo; Gillner, Sten; Haavik, Laurel J; Hartmann, Henrik; Hereş, Ana-Maria; Hultine, Kevin R; Janda, Pavel; Kane, Jeffrey M; Kharuk, Vyacheslav I; Kitzberger, Thomas; Klein, Tamir; Kramer, Koen; Lens, Frederic; Levanic, Tom; Linares Calderon, Juan C; Lloret, Francisco; Lobo-Do-Vale, Raquel; Lombardi, Fabio; López Rodríguez, Rosana; Mäkinen, Harri; Mayr, Stefan; Mészáros, Ilona; Metsaranta, Juha M; Minunno, Francesco; Oberhuber, Walter; Papadopoulos, Andreas; Peltoniemi, Mikko; Petritan, Any M; Rohner, Brigitte; Sangüesa-Barreda, Gabriel; Sarris, Dimitrios; Smith, Jeremy M; Stan, Amanda B; Sterck, Frank; Stojanović, Dejan B; Suarez, Maria L; Svoboda, Miroslav; Tognetti, Roberto; Torres-Ruiz, José M; Trotsiuk, Volodymyr; Villalba, Ricardo; Vodde, Floor; Westwood, Alana R; Wyckoff, Peter H; Zafirov, Nikolay; Martínez-Vilalta, Jordi

    2017-04-01

    Tree mortality is a key factor influencing forest functions and dynamics, but our understanding of the mechanisms leading to mortality and the associated changes in tree growth rates are still limited. We compiled a new pan-continental tree-ring width database from sites where both dead and living trees were sampled (2970 dead and 4224 living trees from 190 sites, including 36 species), and compared early and recent growth rates between trees that died and those that survived a given mortality event. We observed a decrease in radial growth before death in ca. 84% of the mortality events. The extent and duration of these reductions were highly variable (1-100 years in 96% of events) due to the complex interactions among study species and the source(s) of mortality. Strong and long-lasting declines were found for gymnosperms, shade- and drought-tolerant species, and trees that died from competition. Angiosperms and trees that died due to biotic attacks (especially bark-beetles) typically showed relatively small and short-term growth reductions. Our analysis did not highlight any universal trade-off between early growth and tree longevity within a species, although this result may also reflect high variability in sampling design among sites. The intersite and interspecific variability in growth patterns before mortality provides valuable information on the nature of the mortality process, which is consistent with our understanding of the physiological mechanisms leading to mortality. Abrupt changes in growth immediately before death can be associated with generalized hydraulic failure and/or bark-beetle attack, while long-term decrease in growth may be associated with a gradual decline in hydraulic performance coupled with depletion in carbon reserves. Our results imply that growth-based mortality algorithms may be a powerful tool for predicting gymnosperm mortality induced by chronic stress, but not necessarily so for angiosperms and in case of intense drought or

  17. A synthesis of radial growth patterns preceding tree mortality

    USGS Publications Warehouse

    Cailleret, Maxime; Jansen, Steven; Robert, Elisabeth M.R.; Desoto, Lucia; Aakala, Tuomas; Antos, Joseph A.; Beikircher, Barbara; Bigler, Christof; Bugmann, Harald; Caccianiga, Marco; Cada, Vojtech; Camarero, Jesus J.; Cherubini, Paolo; Cochard, Herve; Coyea, Marie R.; Cufar, Katarina; Das, Adrian J.; Davi, Hendrik; Delzon, Sylvain; Dorman, Michael; Gea-Izquierdo, Guillermo; Gillner, Sten; Haavik, Laurel J.; Hartmann, Henrik; Heres, Ana-Maria; Hultine, Kevin R.; Janda, Pavel; Kane, Jeffrey M.; Kharuk, Vyacheslav I.; Kitzberger, Thomas; Klein, Tamir; Kramer, Koen; Lens, Frederic; Levanic, Tom; Calderon, Juan C. Linares; Lloret, Francisco; Lobo-Do-Vale, Raquel; Lombardi, Fabio; Lopez Rodriguez, Rosana; Makinen, Harri; Mayr, Stefan; Meszaros, IIona; Metsaranta, Juha M.; Minunno, Francesco; Oberhuber, Walter; Papadopoulos, Andreas; Peltoniemi, Mikko; Petritan, Any M.; Rohner, Brigitte; Sanguesa-Barreda, Gabriel; Sarris, Dimitrios; Smith, Jeremy M.; Stan, Amanda B.; Sterck, Frank; Stojanovic, Dejan B.; Suarez, Maria L.; Svoboda, Miroslav; Tognetti, Roberto; Torres-Ruiz, Jose M.; Trotsiuk, Volodymyr; Villalba, Ricardo; Vodde, Floor; Westwood, Alana R.; Wyckoff, Peter H.; Zafirov, Nikolay; Martinez-Vilalta, Jordi

    2017-01-01

    Tree mortality is a key factor influencing forest functions and dynamics, but our understanding of the mechanisms leading to mortality and the associated changes in tree growth rates are still limited. We compiled a new pan-continental tree-ring width database from sites where both dead and living trees were sampled (2970 dead and 4224 living trees from 190 sites, including 36 species), and compared early and recent growth rates between trees that died and those that survived a given mortality event. We observed a decrease in radial growth before death in ca. 84% of the mortality events. The extent and duration of these reductions were highly variable (1–100 years in 96% of events) due to the complex interactions among study species and the source(s) of mortality. Strong and long-lasting declines were found for gymnosperms, shade- and drought-tolerant species, and trees that died from competition. Angiosperms and trees that died due to biotic attacks (especially bark-beetles) typically showed relatively small and short-term growth reductions. Our analysis did not highlight any universal trade-off between early growth and tree longevity within a species, although this result may also reflect high variability in sampling design among sites. The intersite and interspecific variability in growth patterns before mortality provides valuable information on the nature of the mortality process, which is consistent with our understanding of the physiological mechanisms leading to mortality. Abrupt changes in growth immediately before death can be associated with generalized hydraulic failure and/or bark-beetle attack, while long-term decrease in growth may be associated with a gradual decline in hydraulic performance coupled with depletion in carbon reserves. Our results imply that growth-based mortality algorithms may be a powerful tool for predicting gymnosperm mortality induced by chronic stress, but not necessarily so for angiosperms and in case of intense drought or

  18. 26 CFR 25.2504-1 - Taxable gifts for preceding calendar periods.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 26 Internal Revenue 14 2011-04-01 2010-04-01 true Taxable gifts for preceding calendar periods. 25... § 25.2504-1 Taxable gifts for preceding calendar periods. (a) In order to determine the correct gift tax liability for any calendar period it is necessary to ascertain the correct amount, if any, of...

  19. 26 CFR 25.2504-1 - Taxable gifts for preceding calendar periods.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 26 Internal Revenue 14 2013-04-01 2013-04-01 false Taxable gifts for preceding calendar periods... § 25.2504-1 Taxable gifts for preceding calendar periods. (a) In order to determine the correct gift tax liability for any calendar period it is necessary to ascertain the correct amount, if any, of...

  20. 26 CFR 25.2504-1 - Taxable gifts for preceding calendar periods.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 26 Internal Revenue 14 2012-04-01 2012-04-01 false Taxable gifts for preceding calendar periods... § 25.2504-1 Taxable gifts for preceding calendar periods. (a) In order to determine the correct gift tax liability for any calendar period it is necessary to ascertain the correct amount, if any, of...

  1. 26 CFR 25.2504-1 - Taxable gifts for preceding calendar periods.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 26 Internal Revenue 14 2010-04-01 2010-04-01 false Taxable gifts for preceding calendar periods... § 25.2504-1 Taxable gifts for preceding calendar periods. (a) In order to determine the correct gift tax liability for any calendar period it is necessary to ascertain the correct amount, if any, of...

  2. 26 CFR 25.2504-1 - Taxable gifts for preceding calendar periods.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 26 Internal Revenue 14 2014-04-01 2013-04-01 true Taxable gifts for preceding calendar periods. 25... § 25.2504-1 Taxable gifts for preceding calendar periods. (a) In order to determine the correct gift tax liability for any calendar period it is necessary to ascertain the correct amount, if any, of...

  3. Perspective-Free Pragmatics: Broken Precedents and the Recovery-from-Preemption Hypothesis

    ERIC Educational Resources Information Center

    Kronmuller, Edmundo; Barr, Dale J.

    2007-01-01

    When speakers refer to the same referent multiple times in a conversation, they tend to follow established patterns of usage, known as "conversational precedents." Research has found that listeners expect speakers to follow precedents, and that this expectation guides their search for referents (Barr, D. J., & Keysar, B. (2002). "Anchoring…

  4. Calcium/Vitamin D Supplementation and Coronary Artery Calcification

    PubMed Central

    Manson, JoAnn E.; Allison, Matthew A.; Carr, J. Jeffrey; Langer, Robert D.; Cochrane, Barbara B.; Hendrix, Susan L.; Hsia, Judith; Hunt, Julie R.; Lewis, Cora E.; Margolis, Karen L.; Robinson, Jennifer G.; Rodabough, Rebecca J.; Thomas, Asha M.

    2010-01-01

    Objectives Coronary artery calcified plaque is a marker for atheromatous plaque burden and predicts future risk of cardiovascular events. The relationship between calcium plus vitamin D supplementation and coronary artery calcium (CAC) has not been previously assessed in a randomized trial setting. We compared coronary artery calcium scores among women randomized to calcium/vitamin D supplementation versus placebo following trial completion. Methods In an ancillary substudy of women randomized to calcium carbonate (1000 mg of elemental calcium daily) plus vitamin D3 (400 IU daily) versus placebo, nested within the Women’s Health Initiative trial of estrogen among women with hysterectomy, we measured CAC with cardiac computed tomography in 754 women aged 50–59 years at randomization. Imaging for CAC was performed at 28 of 40 centers following a mean of 7 years of treatment and scans were read centrally. Coronary artery calcium scores were measured by a central reading center with masking to randomization assignments. Results Post-trial CAC measurements were similar in women randomized to calcium/vitamin D supplementation (calcium/D) and those receiving placebo. The mean CAC score was 91.6 for calcium/D and 100.5 for placebo (rank test p-value=0.74). After adjustment for coronary risk factors, multivariate odds ratios for increasing CAC score cutpoints (CAC >0, ≥10, and ≥100) for calcium/D vs placebo were 0.92 (95% confidence interval, 0.64–1.34), 1.29 (0.88–1.87), and 0.90 (0.56–1.44), respectively. Corresponding odds ratios among women with >50% adherence to study pills and for higher levels of CAC (>300), were similar. Conclusions Treatment with moderate doses of calcium plus vitamin D3 did not appear to alter coronary artery calcified plaque burden among postmenopausal women. PMID:20551849

  5. Software for simulating calcium-triggered exocytotic processes.

    PubMed

    Carrera, Germán; Gil, Amparo; Segura, Javier; Soria, Bernat

    2007-02-01

    We describe a software package for the simulation of exocytotic events from readily releasable pools of secretory vesicles in neuroendocrine cells and presynaptic terminals. The visual package Ca3D_Exolab simulates the entry of Ca(2+) through the calcium channels, the kinetic reactions of calcium with buffers, the diffusion of calcium and mobile buffers, and the kinetic reactions of calcium with the secretory vesicles. The location of both channels and secretory vesicles can be set by using a graphical interface. Calcium and buffer concentrations at different depths from the cellular membrane and capacitance time courses are obtained as outputs. The software package also provides a descriptive statistical data analysis of the different output data.

  6. Calcium transients during early development in single starfish (Asterias forbesi) oocytes

    PubMed Central

    1984-01-01

    Maturation and fertilization of the starfish oocyte are putative calcium-dependent events. We have investigated the spatial distribution and temporal dynamics of this calcium dependence in single oocytes of Asterias forbesi. We used the calcium photoprotein, aequorin, in conjunction with a microscope-photomultiplier and microscope-image intensifier. Surprisingly, in contrast to earlier work with Marasthenias glacialis, there is no detectable increase in intracellular-free calcium in the oocyte of A. forbesi in response to the maturation hormone 1-methyl adenine. During fertilization of the same, matured, A. forbesi oocyte there is a large increase in intracellular-free calcium. The calcium concentration increases to approximately 1 microM at the point of insemination and the region of elevated free calcium expands across the oocyte in approximately 20 s (17-19 degrees C). After the entire oocyte reaches an elevated concentration of free calcium, the concentration decreases uniformly throughout the oocyte over the next several minutes. PMID:6490725

  7. Calcium Channel Blockers

    MedlinePlus

    ... such as high blood pressure, chest pain and Raynaud's disease. Find out more about this class of medication. ... Irregular heartbeats (arrhythmia) Some circulatory conditions, such as Raynaud's disease For black people and older people, calcium channel ...

  8. Stoichiometry of Calcium Medicines

    ERIC Educational Resources Information Center

    Pinto, Gabriel

    2005-01-01

    The topic of calcium supplement and its effects on human lives is presented in the way of questions to the students. It enables the students to realize the relevance of chemistry outside the classroom surrounding.

  9. Calcium-D-glucarate.

    PubMed

    2002-08-01

    Calcium-D-glucarate is the calcium salt of D-glucaric acid, a substance produced naturally in small amounts by mammals, including humans. Glucaric acid is also found in many fruits and vegetables with the highest concentrations to be found in oranges, apples, grapefruit, and cruciferous vegetables. Oral supplementation of calcium-D-glucarate has been shown to inhibit beta-glucuronidase, an enzyme produced by colonic microflora and involved in Phase II liver detoxification. Elevated beta-glucuronidase activity is associated with an increased risk for various cancers, particularly hormone-dependent cancers such as breast, prostate, and colon cancers. Other potential clinical applications of oral calcium-D-glucarate include regulation of estrogen metabolism and as a lipid-lowering agent.

  10. Multiple paternity and postcopulatory sexual selection in a hermaphrodite: what influences sperm precedence in the garden snail Helix aspersa?

    PubMed

    Evanno, Guillaume; Madec, Luc; Arnaud, Jean-François

    2005-03-01

    Sperm competition has been studied in many gonochoric animals but little is known about its occurrence in simultaneous hermaphrodites, especially in land snails. The reproductive behaviour of the land snail Helix aspersa involves several features, like multiple mating, long-term sperm storage and dart-shooting behaviour, which may promote sperm competition. Cryptic female choice may also occur through a spermatheca subdivided into tubules, which potentially allows compartmentalized sperm storage of successive mates. In order to determine the outcome of postcopulatory sexual selection in this species, we designed a cross-breeding experiment where a recipient ('female') mated with two sperm donors ('males'). Mates came from either the same population as the recipient or from a distinct one. To test for the influence a recipient can have on the paternity of its offspring, we excluded the effects of dart shooting by using only virgin snails as sperm donors because they do not shoot any dart before their first copulation. We measured the effects of size of mates as well as time to first and second mating on second mate sperm precedence (P2; established using microsatellite markers). Multiple paternity was detected in 62.5% of clutches and overall there was first-mate sperm precedence with a mean P2 of 0.24. Generalized linear modelling revealed that the best predictors of paternity were the time between matings and the time before first mating. Overall, both first and second mates that copulated quickly got greater parentage, which may suggest that postcopulatory events influence patterns of sperm precedence in the garden snail.

  11. A basal dromaeosaurid and size evolution preceding avian flight.

    PubMed

    Turner, Alan H; Pol, Diego; Clarke, Julia A; Erickson, Gregory M; Norell, Mark A

    2007-09-07

    Fossil evidence for changes in dinosaurs near the lineage leading to birds and the origin of flight has been sparse. A dinosaur from Mongolia represents the basal divergence within Dromaeosauridae. The taxon's small body size and phylogenetic position imply that extreme miniaturization was ancestral for Paraves (the clade including Avialae, Troodontidae, and Dromaeosauridae), phylogenetically earlier than where flight evolution is strongly inferred. In contrast to the sustained small body sizes among avialans throughout the Cretaceous Period, the two dinosaurian lineages most closely related to birds, dromaeosaurids and troodontids, underwent four independent events of gigantism, and in some lineages size increased by nearly three orders of magnitude. Thus, change in theropod body size leading to flight's origin was not unidirectional.

  12. Calcium-sensing receptors.

    PubMed

    Goodman, William G

    2004-01-01

    It is now known that variations in extracellular calcium concentration exert diverse physiologic effects in a variety of tissues that are mediated by a calcium-sensing receptor (CaSRs). In parathyroid tissue, the CaSR represents the molecular mechanism by which parathyroid cells detect changes in blood ionized calcium concentration, modulate parathyroid hormone (PTH) secretion accordingly, and thus maintain serum calcium levels within a narrow physiologic range. In the kidney, the CaSR regulates renal calcium excretion and influences the transepithelial movement of water and other electrolytes. More generally, activation of the CaSR represents an important signal transduction pathway in intestine, placenta, brain, and perhaps bone. Some of these actions involve cell cycle regulation, changes that may be relevant to understanding the pathogenesis of parathyroid gland hyperplasia in secondary hyperparathyroidism caused by chronic kidney disease. The CaSR represents an appealing target for therapeutic agents designed to modify parathyroid gland function in vivo, offering the prospect of novel therapies for selected disorders of bone and mineral metabolism. Other receptors capable of responding to extracellular calcium ions also have been identified, but the functional importance of these interactions remains to be determined.

  13. Inhibition of gravitropism in oat coleoptiles by calcium chelation

    NASA Technical Reports Server (NTRS)

    Roux, S. J.

    1984-01-01

    Some cellular event necessary for gravitropism is inhibited by EGTA without interferring with the overall growth. Calcium relieves this inhibition and demonstrates both that inhibition is reversible and was probably due to a reduction in the ability to free calcium required for one or more at the transduction steps of gravitropism. At the near neutral pH used, EGTA is charged and would not be expected to readily cross the membrane. One of its primary effects, then, is probably the bringing of free calcium in the apoplastic space exterior to the cell membranes.

  14. Oxidative calcium release from catechol.

    PubMed

    Riley, Patrick A; Stratford, Michael R L

    2015-04-01

    Oxidation of 4-methylcatechol previously exposed to aqueous calcium chloride was shown by ion chromatography to be associated with release of calcium ions. The catechol was oxidised to the corresponding orthoquinone by the use of tyrosinase from Agaricus bisporus. The oxidative release of calcium from the catechol is ascribed to the diminution of the available hydroxyl functions able to act as chelating groups. Our results suggest that the redox status of melanin may regulate calcium binding and influence calcium levels in pigmented cells.

  15. Variations of the electromagnetic field that preceded the Peruvian M7.0 earthquake occurred on September 25, 2013

    NASA Astrophysics Data System (ADS)

    Cataldi, Daniele; Cataldi, Gabriele; Straser, Valentino

    2014-05-01

    Through this work we want to highlight the existence of strong electromagnetic emission in the ELF band that preceded the M7, 0 earthquake occurred in Peru on September 25, 2013 at 16:42:42 UTC. The electromagnetic activity data were provided by the monitoring station of Radio Emissions Project (Cecchina, Albano Laziale, Rome, Italy). The monitoring of electromagnetic field takes place 24H24, 7 days on 7, through a prototype of a ELF radio receiver (gain = 57dB) connected to a loop antenna with diameter of 1x1 meters (square section) and contains 25 turns. The antenna is oriented at 306° NW. The data on M7, 0 earthquakes were provided by USGS. The monitoring station has detected intense impulsive emissions starting from 13:55 UTC until, approximately, to 16:40 UTC. These emissions have a very high intensity and have shown just a few hours before the M7.0 earthquake. Seeing as have not been registered radio emission of this intensity for more than 24 before, we think that these signals can be associated with the Peruvian earthquake. Radio emissions with these characteristics have been recorded many times by the monitoring station of Radio Emissions Project, and in all cases have preceded of some hours the M6+ seismic events occurred on a global scale. Key words: Earthquake prediction, ELF, Seismic Electromagnetic Precursor (SEP), Seismic Geomagnetic Precursor (SGP), Geomagnetic emissions.

  16. Prognostic value of human papillomavirus 16/18 genotyping in low-grade cervical lesions preceded by mildly abnormal cytology*

    PubMed Central

    Ye, Jing; Cheng, Bei; Cheng, Yi-fan; Yao, Ye-li; Xie, Xing; Lu, Wei-guo; Cheng, Xiao-dong

    2017-01-01

    Histological low-grade squamous intraepithelial lesion/cervical intraepithelial neoplasia grade 1 (LSIL/CIN1) preceded by normal or mildly abnormal cytology is recommended for conservative follow-up, with no separated management. In this study, we assessed the triage value of human papillomavirus (HPV) 16/18 genotyping in 273 patients with LSIL/CIN1. HPV16/18 genotyping was performed at baseline and follow-up was at 6-monthly intervals for up to 2 years. At each follow-up, women positive for cytology or high-risk HPV (hrHPV) were referred for colposcopy. Enrollment cytology, HPV16/18 genotyping, and questionnaire-obtained factors were linked to the 2-year cumulative progression rate. Univariate and multivariate analyses were performed taking into account time-to-event with Cox proportional hazard regression. The results showed that 190 cases (69.6%) regressed, 37 (13.6%) persisted, and 46 (16.8%) progressed. HPV16/18 positivity (hazard ratio (HR), 2.708; 95% confidence interval (CI), 1.432–5.121; P=0.002) is significantly associated with higher 2-year cumulative progression rate. Sub-analysis by enrollment cytology and age restricted the positive association among patients preceded by mildly abnormal cytology and aged 30 years or older. Immediate treatment is a rational recommendation for the high-risk subgroup, when good compliance is not assured. PMID:28271660

  17. Golgi fragmentation precedes neuromuscular denervation and is associated with endosome abnormalities in SOD1-ALS mouse motor neurons

    PubMed Central

    2014-01-01

    Background Fragmentation of stacked cisterns of the Golgi apparatus into dispersed smaller elements is a feature associated with degeneration of neurons in amyotrophic lateral sclerosis (ALS) and some other neurodegenerative disorders. However, the role of Golgi fragmentation in motor neuron degeneration is not well understood. Results Here we use a SOD1-ALS mouse model (low-copy Gurney G93A-SOD1 mouse) to show that motor neurons with Golgi fragmentation are retrogradely labeled by intramuscularly injected CTB (beta subunit of cholera toxin), indicating that Golgi fragmentation precedes neuromuscular denervation and axon retraction. We further show that Golgi fragmentation may occur in the absence of and precede two other pathological markers, i.e. somatodendritic SOD1 inclusions, and the induction of ATF3 expression. In addition, we show that Golgi fragmentation is associated with an altered dendritic organization of the Golgi apparatus, does not depend on intact apoptotic machinery, and is facilitated in transgenic mice with impaired retrograde dynein-dependent transport (BICD2-N mice). A connection to altered dynein-dependent transport also is suggested by reduced expression of endosomal markers in neurons with Golgi fragmentation, which also occurs in neurons with impaired dynein function. Conclusions Together the data indicate that Golgi fragmentation is a very early event in the pathological cascade in ALS that is associated with altered organization of intracellular trafficking. PMID:24708899

  18. Oxidative stress and susceptibility to mitochondrial permeability transition precedes the onset of diabetes in autoimmune non-obese diabetic mice.

    PubMed

    Malaguti, C; La Guardia, P G; Leite, A C R; Oliveira, D N; de Lima Zollner, R L; Catharino, R R; Vercesi, A E; Oliveira, H C F

    2014-12-01

    Beta cell destruction in type 1 diabetes (TID) is associated with cellular oxidative stress and mitochondrial pathway of cell death. The aim of this study was to determine whether oxidative stress and mitochondrial dysfunction are present in T1D model (non-obese diabetic mouse, NOD) and if they are related to the stages of disease development. NOD mice were studied at three stages: non-diabetic, pre-diabetic, and diabetic and compared with age-matched Balb/c mice. Mitochondria respiration rates measured at phosphorylating and resting states in liver and soleus biopsies and in isolated liver mitochondria were similar in NOD and Balb/c mice at the three disease stages. However, NOD liver mitochondria were more susceptible to calcium-induced mitochondrial permeability transition as determined by cyclosporine-A-sensitive swelling and by decreased calcium retention capacity in all three stages of diabetes development. Mitochondria H2O2 production rate was higher in non-diabetic, but unaltered in pre-diabetic and diabetic NOD mice. The global cell reactive oxygen species (ROS), but not specific mitochondria ROS production, was significantly increased in NOD lymphomononuclear and stem cells in all disease stages. In addition, marked elevated rates of 2',7'-dichlorodihydrofluorescein (H2DCF) oxidation were observed in pancreatic islets from non-diabetic NOD mice. Using matrix-assisted laser desorption/ionization (MALDI) mass spectrometry (MS) and lipidomic approach, we identified oxidized lipid markers in NOD liver mitochondria for each disease stage, most of them being derivatives of diacylglycerols and phospholipids. These results suggest that the cellular oxidative stress precedes the establishment of diabetes and may be the cause of mitochondrial dysfunction that is involved in beta cell death.

  19. Elliott's ethics of expertise proposal and application: a dangerous precedent.

    PubMed

    Calabrese, Edward J

    2007-06-01

    In a recent paper in Science and Engineering Ethics (SEE) Elliott proposed an ethics of expertise, providing its theoretical foundation along with its application in a case study devoted to the topic of hormesis. The application is based on a commentary in the journal Nature, and it includes assertions of ethical breaches. Elliott concludes that the authors of the commentary failed to promote the informed consent of decision makers by not providing representative information about alternative frequency estimates of hormesis in the literature, thereby hindering the capacity of the scientific community to promote informed consent relating to chemical regulation. This paper argues that Elliott should have incorporated due process into his system of evaluation. His argument is also seriously deficient technically, in that it misinterprets the toxicological issues, misrepresents the scientific literature with respect to the frequency of hormesis, and incorrectly assesses the extent to which the Nature paper revealed opposing/alternative views on hormesis. Given the seriousness of assertions of noncompliance to ethical norms, there must be procedures to protect those whose ethics were called into question, to fairly evaluate the technical justification for an assertion, and to enable corrections in the event of errors. If a journal is willing to publish assertions that individuals acted in an ethically questionable way, it should be guided by a documented code of ethics and meet a standard of responsibility far greater than normal peer-review processes for papers that do not entail such ethical judgments.

  20. [Microbial geochemical calcium cycle].

    PubMed

    Zavarzin, G A

    2002-01-01

    The participation of microorganisms in the geochemical calcium cycle is the most important factor maintaining neutral conditions on the Earth. This cycle has profound influence on the fate of inorganic carbon, and, thereby, on the removal of CO2 from the atmosphere. The major part of calcium deposits was formed in the Precambrian, when prokaryotic biosphere predominated. After that, calcium recycling based on biogenic deposition by skeletal organisms became the main process. Among prokaryotes, only a few representatives, e.g., cyanobacteria, exhibit a special calcium function. The geochemical calcium cycle is made possible by the universal features of bacteria involved in biologically mediated reactions and is determined by the activities of microbial communities. In the prokaryotic system, the calcium cycle begins with the leaching of igneous rock predominantly through the action of the community of organotrophic organisms. The release of carbon dioxide to the soil air by organotrophic aerobes leads to leaching with carbonic acid and soda salinization. Under anoxic conditions, of major importance is the organic acid production by primary anaerobes (fermentative microorganisms). Calcium carbonate is precipitated by secondary anaerobes (sulfate reducers) and to a smaller degree by methanogens. The role of the cyanobacterial community in carbonate deposition is exposed by stromatolites, which are the most common organo-sedimentary Precambrian structures. Deposition of carbonates in cyanobacterial mats as a consequence of photoassimilation of CO2 does not appear to be a significant process. It is argued that carbonates were deposited at the boundary between the "soda continent", which emerged as a result of subaerial leaching with carbonic acid, and the ocean containing Ca2+. Such ecotones provided favorable conditions for the development of the benthic cyanobacterial community, which was a precursor of stromatolites.

  1. Analysis of spontaneous and nerve-evoked calcium transients in intact extraocular muscles in vitro.

    PubMed

    Feng, Cheng-Yuan; Hennig, Grant W; Corrigan, Robert D; Smith, Terence K; von Bartheld, Christopher S

    2012-07-01

    Extraocular muscles (EOMs) have unique calcium handling properties, yet little is known about the dynamics of calcium events underlying ultrafast and tonic contractions in myofibers of intact EOMs. Superior oblique EOMs of juvenile chickens were dissected with their nerve attached, maintained in oxygenated Krebs buffer, and loaded with fluo-4. Spontaneous and nerve stimulation-evoked calcium transients were recorded and, following calcium imaging, some EOMs were double-labeled with rhodamine-conjugated alpha-bungarotoxin (rhBTX) to identify EOM myofiber types. EOMs showed two main types of spontaneous calcium transients, one slow type (calcium waves with 1/2(max) duration of 2-12 s, velocity of 25-50 μm/s) and two fast "flash-like" types (Type 1, 30-90 ms; Type 2, 90-150 ms 1/2(max) duration). Single pulse nerve stimulation evoked fast calcium transients identical to the fast (Type 1) calcium transients. Calcium waves were accompanied by a local myofiber contraction that followed the calcium transient wavefront. The magnitude of calcium-wave induced myofiber contraction far exceeded those of movement induced by nerve stimulation and associated fast calcium transients. Tetrodotoxin eliminated nerve-evoked transients, but not spontaneous transients. Alpha-bungarotoxin eliminated both spontaneous and nerve-evoked fast calcium transients, but not calcium waves, and caffeine increased wave activity. Calcium waves were observed in myofibers lacking spontaneous or evoked fast transients, suggestive of multiply-innervated myofibers, and this was confirmed by double-labeling with rhBTX. We propose that the abundant spontaneous calcium transients and calcium waves with localized contractions that do not depend on innervation may contribute to intrinsic generation of tonic functions of EOMs.

  2. Analysis of Spontaneous and Nerve-Evoked Calcium Transients in Intact Extraocular Muscles in Vitro

    PubMed Central

    Feng, Cheng-Yuan; Hennig, Grant W.; Corrigan, Robert D.; Smith, Terence K.; von Bartheld, Christopher S.

    2012-01-01

    Extraocular muscles (EOMs) have unique calcium handling properties, yet little is known about the dynamics of calcium events underlying ultrafast and tonic contractions in myofibers of intact EOMs. Superior oblique EOMs of juvenile chickens were dissected with their nerve attached, maintained in oxygenated Krebs buffer, and loaded with fluo-4. Spontaneous and nerve stimulation-evoked calcium transients were recorded and, following calcium imaging, some EOMs were double-labeled with rhodamine-conjugated alpha-bungarotoxin (rhBTX) to identify EOM myofiber types. EOMs showed two main types of spontaneous calcium transients, one slow type (calcium waves with 1/2max duration of 2–12 s, velocity of 25–50 μm/s) and two fast “flash-like” types (Type 1, 30–90 ms; Type 2, 90–150 ms 1/2max duration). Single pulse nerve stimulation evoked fast calcium transients identical to the fast (Type 1) calcium transients. Calcium waves were accompanied by a local myofiber contraction that followed the calcium transient wavefront. The magnitude of calcium-wave induced myofiber contraction far exceeded those of movement induced by nerve stimulation and associated fast calcium transients. Tetrodotoxin eliminated nerve-evoked transients, but not spontaneous transients. Alpha-bungarotoxin eliminated both spontaneous and nerve-evoked fast calcium transients, but not calcium waves, and caffeine increased wave activity. Calcium waves were observed in myofibers lacking spontaneous or evoked fast transients, suggestive of multiply-innervated myofibers, and this was confirmed by double-labeling with rhBTX. We propose that the abundant spontaneous calcium transients and calcium waves with localized contractions that do not depend on innervation may contribute to intrinsic generation of tonic functions of EOMs. PMID:22579493

  3. Calcium metabolism and correcting calcium deficiencies.

    PubMed

    Emkey, Ronald D; Emkey, Gregory R

    2012-09-01

    Calcium is the most abundant cation in the human body, of which approximately 99% occurs in bone, contributing to its rigidity and strength. Bone also functions as a reservoir of Ca for its role in multiple physiologic and biochemical processes. This article aims to provide a thorough understanding of the absorptive mechanisms and factors affecting these processes to enable one to better appreciate an individual's Ca needs, and to provide a rationale for correcting Ca deficiencies. An overview of Ca requirements and suggested dosing regimens is presented, with discussion of various Ca preparations and potential toxicities of Ca treatment.

  4. Onset and Offset of Aversive Events Establish Distinct Memories Requiring Fear and Reward Networks

    ERIC Educational Resources Information Center

    Andreatta, Marta; Fendt, Markus; Muhlberger, Andreas; Wieser, Matthias J.; Imobersteg, Stefan; Yarali, Ayse; Gerber, Bertram; Pauli, Paul

    2012-01-01

    Two things are worth remembering about an aversive event: What made it happen? What made it cease? If a stimulus precedes an aversive event, it becomes a signal for threat and will later elicit behavior indicating conditioned fear. However, if the stimulus is presented upon cessation of the aversive event, it elicits behavior indicating…

  5. Inositol trisphosphate and calcium signalling

    NASA Astrophysics Data System (ADS)

    Berridge, Michael J.

    1993-01-01

    Inositol trisphosphate is a second messenger that controls many cellular processes by generating internal calcium signals. It operates through receptors whose molecular and physiological properties closely resemble the calcium-mobilizing ryanodine receptors of muscle. This family of intracellular calcium channels displays the regenerative process of calcium-induced calcium release responsible for the complex spatiotemporal patterns of calcium waves and oscillations. Such a dynamic signalling pathway controls many cellular processes, including fertilization, cell growth, transformation, secretion, smooth muscle contraction, sensory perception and neuronal signalling.

  6. The influence of behavior preceding a reinforced response on behavior change in the classroom.

    PubMed

    Kazdin, A E

    1977-01-01

    The influence of behavior that immediately precedes a reinforced target response on the effectiveness of a reinforcement contingency was examined in two experiments with mentally retarded children in a special-education classroom. Two reinforcement schedules were examined in each experiment. For each schedule, a prespecified period of attentive behavior served as the target response. The schedules differed in whether inattentive or attentive behavior was required immediately to precede the target response. These schedules were examined with one child in a simultaneous treatment design using praise as the reinforcer (Experiment I), and with two children in separate reversal designs using tokens as the reinforcer (Experiment II). While attentive behavior increased under each schedule, the increase was greater when attentive rather than inattentive behavior preceded the reinforced response. The results indicated that the effect of a contingency may be determined not only by the specific response reinforced but also by the behavior that immediately precedes that response.

  7. Historical Uses of Meteoritic Metals as Precedent for Modern In-Situ Asteroid Mining

    NASA Astrophysics Data System (ADS)

    Krispin, D.; Mardon, A. A.; Fawcett, B. G.

    2016-08-01

    The strain on earth's resources of metal and the metallic density of meteorites mean that in situ asteroid mining is advisable. This has precedent: Use of meteoritic metal dates back to ancient times.

  8. Precedency control and other semantic integrity issues in a workbench database

    NASA Technical Reports Server (NTRS)

    Dampney, C. N. G.

    1983-01-01

    Most database systems model the current state of a system of real world discrete and simple entities together with their relationships. By examining instead a database system that is a workbench and models more complicated entities, a fresh perspective is gained. Specifically, semantic integrity is analysed. Four aspects distinct from physical integrity are identified, namely - access, failure, concurrency and precedency. Access control is shown to be the consequence of semantic interdependency between data and its matching semantic routines. Failure, concurrency precedency controls are concerned with preventing processes interfering with each other. Precedency is a new concept in the database context. It expresses a constraint between processes that act on the database. As processes create, update and delete entities they in general obey a partial ordering imposed by the semantics of their actions. Precedency control ensures that data remains consistent with respect to this partial order.

  9. Localization of intracellular calcium release in cells injured by venom from the ectoparasitoid Nasonia vitripennis (Walker) (Hymenoptera: Pteromalidae) and dependence of calcium mobilization on G-protein activation.

    PubMed

    Rivers, David B; Crawley, Timothy; Bauser, Holly

    2005-02-01

    Venom from the ectoparasitic wasp Nasonia vitripennis induces cellular injury that appears to involve the release of intracellular calcium stores via the activation of phospholipase C, and culminates in oncotic death. A linkage between release of intracellular Ca2+ and oncosis has not been clearly established and was the focus of this study. When BTI-TN-5B1-4 cells were treated with suramin, an uncoupler of G-proteins, venom-induced swelling and oncotic death were inhibited in a dose-dependent manner for at least 24 h. Suramin also blocked increases in free cytosolic [Ca2+], arguing that venom induces calcium mobilization through G-protein signaling pathways. Endoplasmic reticulum (ER) was predicted to be the source of intracellular calcium release, but labeling with the fluorescent probe ER-tracker revealed no indication of organelle swelling or loss of membrane integrity as would be expected if the Ca(2+)-ATPase pump was disabled by crude venom. Incubation of cell monolayers with calmodulin or nitrendipine, modulators of ER calcium release channels, neither attenuated nor augmented the effects of wasp venom. These results suggest that wasp venom stimulates calcium release from ER compartments distinct from RyRs, L-type Ca2+ channels, and the Ca(2+)-ATPase pump, or calcium is released from some other intracellular store. A reduction of mitochondrial membrane potential delta psi(m) appeared to precede a rise in cytosolic free Ca2+ as evidenced by fluorescent microscopy using the calcium-sensitive probe fluo-4 AM. This argues that the initial insult to the cell resulting from venom elicits a rapid loss of (delta psi(m)), followed by unregulated calcium efflux from mitochondria into the cytosol. Mobilization of calcium in this fashion could stimulate cAMP formation, and subsequently promote calcium release from NAADP-sensitive stores.

  10. Gravimetric Determination of Calcium as Calcium Carbonate Hydrate.

    ERIC Educational Resources Information Center

    Henrickson, Charles H.; Robinson, Paul R.

    1979-01-01

    The gravimetric determination of calcium as calcium carbonate is described. This experiment is suitable for undergraduate quantitative analysis laboratories. It is less expensive than determination of chloride as silver chloride. (BB)

  11. EVENT SEGMENTATION

    PubMed Central

    Zacks, Jeffrey M.; Swallow, Khena M.

    2012-01-01

    One way to understand something is to break it up into parts. New research indicates that segmenting ongoing activity into meaningful events is a core component of ongoing perception, with consequences for memory and learning. Behavioral and neuroimaging data suggest that event segmentation is automatic and that people spontaneously segment activity into hierarchically organized parts and sub-parts. This segmentation depends on the bottom-up processing of sensory features such as movement, and on the top-down processing of conceptual features such as actors’ goals. How people segment activity affects what they remember later; as a result, those who identify appropriate event boundaries during perception tend to remember more and learn more proficiently. PMID:22468032

  12. Intraclonal heterogeneity is a critical early event in the development of myeloma and precedes the development of clinical symptoms.

    PubMed

    Walker, B A; Wardell, C P; Melchor, L; Brioli, A; Johnson, D C; Kaiser, M F; Mirabella, F; Lopez-Corral, L; Humphray, S; Murray, L; Ross, M; Bentley, D; Gutiérrez, N C; Garcia-Sanz, R; San Miguel, J; Davies, F E; Gonzalez, D; Morgan, G J

    2014-02-01

    The mechanisms involved in the progression from monoclonal gammopathy of undetermined significance (MGUS) and smoldering myeloma (SMM) to malignant multiple myeloma (MM) and plasma cell leukemia (PCL) are poorly understood but believed to involve the sequential acquisition of genetic hits. We performed exome and whole-genome sequencing on a series of MGUS (n=4), high-risk (HR)SMM (n=4), MM (n=26) and PCL (n=2) samples, including four cases who transformed from HR-SMM to MM, to determine the genetic factors that drive progression of disease. The pattern and number of non-synonymous mutations show that the MGUS disease stage is less genetically complex than MM, and HR-SMM is similar to presenting MM. Intraclonal heterogeneity is present at all stages and using cases of HR-SMM, which transformed to MM, we show that intraclonal heterogeneity is a typical feature of the disease. At the HR-SMM stage of disease, the majority of the genetic changes necessary to give rise to MM are already present. These data suggest that clonal progression is the key feature of transformation of HR-SMM to MM and as such the invasive clinically predominant clone typical of MM is already present at the SMM stage and would be amenable to therapeutic intervention at that stage.

  13. Intraclonal heterogeneity is a critical early event in the development of myeloma and precedes the development of clinical symptoms

    PubMed Central

    Melchor, Lorenzo; Brioli, Annamaria; Johnson, David C; Kaiser, Martin F; Mirabella, Fabio; Lopez-Corral, Lucia; Humphray, Sean; Murray, Lisa; Ross, Mark; Bentley, David; Gutiérrez, Norma C.; Garcia-Sanz, Ramón; San Miguel, Jesus; Davies, Faith E; Gonzalez, David; Morgan, Gareth J

    2013-01-01

    The mechanisms involved in progression from monoclonal gammopathy of undetermined significance (MGUS) and smoldering myeloma (SMM) to malignant multiple myeloma (MM) and plasma cell leukemia (PCL) are poorly understood but believed to involve the sequential acquisition of genetic hits. We performed exome and whole genome sequencing on a series of MGUS (n=4), high risk (HR)-SMM (n=4), MM (n=26) and PCL (n=2) samples, including four cases who transformed from HR-SMM to MM, to determine the genetic factors which drive progression of disease. The pattern and number of non-synonymous mutations show that the MGUS disease stage is less genetically complex than MM, and HR-SMM is similar to presenting MM. Intraclonal heterogeneity is present at all stages and using cases of HR-SMM, which transformed to MM, we show that intraclonal heterogeneity is a typical feature of the disease. At the HR-SMM stage of disease the majority of the genetic changes necessary to give rise to MM are already present. These data suggest that clonal progression is the key feature of transformation of HR-SMM to MM and as such the invasive clinically predominant clone typical of MM is already present at the SMM stage and would be amenable to therapeutic intervention at that stage. PMID:23817176

  14. Late Cretaceous (Maestrichtian) Calcareous Nannoplankton Biogeography with Emphasis on Events Immediately Preceding the Cretaceous/Paleocene Boundary

    DTIC Science & Technology

    1993-02-01

    Sl~~~~~g~ .... .. .. . - ------=----. G.Michael Purdy, Chair t Department of Geology and Geophysics- *"L i ..... John W. Farringto Dean of Graduate...Joint Committee for Marine Geology and Geophysics Massachusetts Institute of Technology/Woods Hole Oceanographic InstitutionI I This work is...Institute of Technology and the Department of Marine Geology and Geophysics, Woods Hole Oceanographic Institution on February 8, 1993 in partial

  15. An improved car-following model with two preceding cars' average speed

    NASA Astrophysics Data System (ADS)

    Yu, Shao-Wei; Shi, Zhong-Ke

    2015-01-01

    To better describe cooperative car-following behaviors under intelligent transportation circumstances and increase roadway traffic mobility, the data of three successive following cars at a signalized intersection of Jinan in China were obtained and employed to explore the linkage between two preceding cars' average speed and car-following behaviors. The results indicate that two preceding cars' average velocity has significant effects on the following car's motion. Then an improved car-following model considering two preceding cars' average velocity was proposed and calibrated based on full velocity difference model and some numerical simulations were carried out to study how two preceding cars' average speed affected the starting process and the traffic flow evolution process with an initial small disturbance, the results indicate that the improved car-following model can qualitatively describe the impacts of two preceding cars' average velocity on traffic flow and that taking two preceding cars' average velocity into account in designing the control strategy for the cooperative adaptive cruise control system can improve the stability of traffic flow, suppress the appearance of traffic jams and increase the capacity of signalized intersections.

  16. Calcium Handling and Arrhythmogenesis.

    PubMed

    Bompotis, Georgios C; Pappas, Loukas K; Angelidis, Christos; Kossyvakis, Charalampos; Giannopoulos, Georgios; Deftereos, Spyridon

    2016-01-01

    Intracellular calcium homeostasis plays a fundamental role in the electric and mechanical function of the heart by modulating action potential pattern and duration, by linking cell membrane depolarization to myocardial contraction and by regulating cardiac automaticity. Abnormalities of intracellular calcium regulation disrupt the electrophysiological properties of the heart and create an arrhythmogenic milieu, which promotes atrial and ventricular arrhythmogenesis and impairs cardiac automaticity and atrioventricular conduction. In this brief review, we summarize the basic genetic, molecular and electrophysiological mechanisms linking inherited or acquired intracellular Ca(2+) dysregulation to arrhythmogenesis.

  17. Calcium metabolism in microgravity.

    PubMed

    Heer, M; Kamps, N; Biener, C; Korr, C; Boerger, A; Zittermann, A; Stehle, P; Drummer, C

    1999-09-09

    Unloading of weight bearing bones as induced by microgravity or immobilization has significant impacts on the calcium and bone metabolism and is the most likely cause for space osteoporosis. During a 4.5 to 6 month stay in space most of the astronauts develop a reduction in bone mineral density in spine, femoral neck, trochanter, and pelvis of 1%-1.6% measured by Dual Energy X-ray Absorption (DEXA). Dependent on the mission length and the individual turnover rates of the astronauts it can even reach individual losses of up to 14% in the femoral neck. Osteoporosis itself is defined as the deterioration of bone tissue leading to enhanced bone fragility and to a consequent increase in fracture risk. Thinking of long-term missions to Mars or interplanetary missions for years, space osteoporosis is one of the major concerns for manned spaceflight. However, decrease in bone density can be initiated differently. It either can be caused by increases in bone formation and bone resorption resulting in a net bone loss, as obtained in fast looser postmenopausal osteoporosis. On the other hand decrease in bone formation and increase in bone resorption also leads to bone losses as obtained in slow looser postmenopausal osteoporosis or in Anorexia Nervosa patients. Biomarkers of bone turnover measured during several missions indicated that the pattern of space osteoporosis is very similar to the pattern of Anorexia Nervosa patients or slow looser postmenopausal osteoporosis. However, beside unloading, other risk factors for space osteoporosis exist such as stress, nutrition, fluid shifts, dehydration and bone perfusion. Especially nutritional factors may contribute considerably to the development of osteoporosis. From earthbound studies it is known that calcium supplementation in women and men can prevent bone loss of 1% bone per year. Based on these results we studied the calcium intake during several European missions and performed an experiment during the German MIR 97 mission

  18. Active and passive calcium transport systems in plant cells: Progress report, January 1986--June 1989

    SciTech Connect

    Sze, H.

    1989-01-01

    The objectives of this proposal are to identify and characterize active (energy-dependent) and passive calcium transport systems that work together to regulate calcium levels in the cytoplasm of plant cells. Several different energy-dependent Ca transport systems have been identified and characterized from oat root tissue (a monocot tissue) and carrot suspension cells (a dicot tissue). They are described in more detail below. I also have included in this progress report our continuing studies to understand the mode of action of the Helminthosporium maydis T toxin. This study was initially supported by a preceding DOE grant. The time needed to complete the study overlapped partly with the present grant period.

  19. Calcium channels, external calcium concentration and cell proliferation.

    PubMed

    Borowiec, Anne-Sophie; Bidaux, Gabriel; Pigat, Natascha; Goffin, Vincent; Bernichtein, Sophie; Capiod, Thierry

    2014-09-15

    Evidence for a role for calcium channel proteins in cell proliferation is numerous suggesting that calcium influx is essential in this physiological process. Several studies in the past thirty years have demonstrated that calcium channel expression levels are determinant in cell proliferation. Voltage-gated, store-operated, second messengers and receptor-operated calcium channels have been associated to cell proliferation. However, the relationship between calcium influx and cell proliferation can be uncoupled in transformed and cancer cells, resulting in an external calcium-independent proliferation. Thus, protein expression could be more important than channel function to trigger cell proliferation suggesting that additional channel functions may be responsible to reconcile calcium channel expression and cell proliferation. When needed, external calcium concentration is obviously important for calcium channel function but it also regulates calcium sensing receptor (CaSR) activity. CaSR can up- or down-regulate cell proliferation depending on physiological conditions. CaSR sensitivity to external calcium is within the 0.5 to 5 mM range and therefore, the role of these receptors in cell proliferation must be taken into account. We therefore suggest here that cell proliferation rates could depend on the relative balance between calcium influx and CaSR activation.

  20. Transformational Events

    ERIC Educational Resources Information Center

    Denning, Peter J.; Hiles, John E.

    2006-01-01

    Transformational Events is a new pedagogic pattern that explains how innovations (and other transformations) happened. The pattern is three temporal stages: an interval of increasingly unsatisfactory ad hoc solutions to a persistent problem (the "mess"), an offer of an invention or of a new way of thinking, and a period of widespread adoption and…

  1. Diet and calcium stones.

    PubMed Central

    Hughes, J; Norman, R W

    1992-01-01

    OBJECTIVE: To review the current literature on the dietary modification of urinary risk factors as a means of reducing the likelihood of recurrent stone formation and to develop practical dietary recommendations that might be useful to this end. DATA SOURCES: MEDLINE was searched for English-language articles published from 1983 to 1990. Additional references were selected from the bibliographies of identified articles. STUDY SELECTION: Nonrandomized trials and retrospective reviews were included because of a paucity of randomized controlled trials. DATA SYNTHESIS: Information on the dietary intake of calcium, oxalate, protein, sodium and fibre and on alcohol and fluid intake was used to develop practical guidelines on dietary modification. CONCLUSION: Dietary modification plays an important role in the reduction of urinary risk factors in patients with calcium stone disease of the urinary tract. As an initial form of prevention attention should be directed toward moderating the intake of calcium, oxalate, protein, sodium and alcohol and increasing the intake of fibre and water. Future research should include an assessment of the long-term reduction of dietary and urinary risk factors and the rates of recurrence of calcium stones. PMID:1310430

  2. Calcium silicate insulation structure

    DOEpatents

    Kollie, Thomas G.; Lauf, Robert J.

    1995-01-01

    An insulative structure including a powder-filled evacuated casing utilizes a quantity of finely divided synthetic calcium silicate having a relatively high surface area. The resultant structure-provides superior thermal insulating characteristics over a broad temperature range and is particularly well-suited as a panel for a refrigerator or freezer or the insulative barrier for a cooler or a insulated bottle.

  3. Calcium biofortification of crops

    Technology Transfer Automated Retrieval System (TEKTRAN)

    More than half of the world's population is deficient in calcium (Ca), iron (Fe), iodine (I), magnesium (Mg), selenium (Se), or zinc (Zn). The consumption of plants, directly or via livestock, containing inadequate concentrations of particular minerals causes these deficiencies. Agronomic and geneti...

  4. High Blood Calcium (Hypercalcemia)

    MedlinePlus

    ... as sarcoidosis • Hormone disorders, such as overactive thyroid (hyperthyroidism) • A genetic condition called familial hypocalciuric hypercalcemia • Kidney ... topics: www.hormone.org (search for PHPT, calcium, hyperthyroidism, or osteoporosis) • MedlinePlus (National Institutes of Health-NIH): ...

  5. Assay for calcium channels

    SciTech Connect

    Glossmann, H.; Ferry, D.R.

    1985-01-01

    This chapter focuses on biochemical assays for Ca/sup 2 +/-selective channels in electrically excitable membranes which are blocked in electrophysiological and pharmacological experiments by verapamil, 1,4-dihydropyridines, diltiazen (and various other drugs), as well as inorganic di- or trivalent cations. The strategy employed is to use radiolabeled 1,4-dihydropyridine derivatives which block calcium channels with ED/sub 50/ values in the nanomolar range. Although tritiated d-cis-diltiazem and verapamil can be used to label calcium channels, the 1,4-dihydropyridines offer numerous advantages. The various sections cover tissue specificity of channel labeling, the complex interactions of divalent cations with the (/sup 3/H)nimodipine-labeled calcium channels, and the allosteric regulation of (/sup 3/H)nimodipine binding by the optically pure enantiomers of phenylalkylamine and benzothiazepine calcium channel blockers. A comparison of the properties of different tritiated 1,4-dihydropyridine radioligands and the iodinated channel probe (/sup 125/I)iodipine is given.

  6. The Role of Animacy and Thematic Relationships in Processing Active English Sentences: Evidence from Event-Related Potentials

    ERIC Educational Resources Information Center

    Kuperberg, Gina R.; Kreher, Donna A.; Sitnikova, Tatiana; Caplan, David N.; Holcomb, Phillip J.

    2007-01-01

    Recent event-related potential studies report a P600 effect to incongruous verbs preceded by semantically associated inanimate noun-phrase (NP) arguments, e.g., "eat" in "At breakfast the eggs would eat...". This P600 effect may reflect the processing cost incurred when semantic-thematic relationships between critical verbs and their preceding NP…

  7. The Plasma Membrane Calcium Pump

    NASA Technical Reports Server (NTRS)

    Rasmussen, H.

    1983-01-01

    Three aspect of cellular calcium metabolism in animal cells was discussed including the importance of the plasma membrane in calcium homeostasis, experiments dealing with the actual mechanism of the calcium pump, and the function of the pump in relationship to the mitochondria and to the function of calmodulin in the intact cell.

  8. Impregnating Coal With Calcium Carbonate

    NASA Technical Reports Server (NTRS)

    Sharma, Pramod K.; Voecks, Gerald E.; Gavalas, George R.

    1991-01-01

    Relatively inexpensive process proposed for impregnating coal with calcium carbonate to increase rates of gasification and combustion of coal and to reduce emission of sulfur by trapping sulfur in calcium sulfide. Process involves aqueous-phase reactions between carbon dioxide (contained within pore network of coal) and calcium acetate. Coal impregnated with CO2 by exposing it to CO2 at high pressure.

  9. Dysregulation of calcium homeostasis in muscular dystrophies.

    PubMed

    Vallejo-Illarramendi, Ainara; Toral-Ojeda, Ivan; Aldanondo, Garazi; López de Munain, Adolfo

    2014-10-08

    Muscular dystrophies are a group of diseases characterised by the primary wasting of skeletal muscle, which compromises patient mobility and in the most severe cases originate a complete paralysis and premature death. Existing evidence implicates calcium dysregulation as an underlying crucial event in the pathophysiology of several muscular dystrophies, such as dystrophinopathies, calpainopathies or myotonic dystrophy among others. Duchenne muscular dystrophy is the most frequent myopathy in childhood, and calpainopathy or LGMD2A is the most common form of limb-girdle muscular dystrophy, whereas myotonic dystrophy is the most frequent inherited muscle disease worldwide. In this review, we summarise recent advances in our understanding of calcium ion cycling through the sarcolemma, the sarcoplasmic reticulum and mitochondria, and its involvement in the pathogenesis of these dystrophies. We also discuss some of the clinical implications of recent findings regarding Ca2+ handling as well as novel approaches to treat muscular dystrophies targeting Ca2+ regulatory proteins.

  10. Cellular Mechanisms of Calcium-Mediated Triggered Activity

    NASA Astrophysics Data System (ADS)

    Song, Zhen

    proteins. How those various factors interact synergistically to promote DADs is not well understood. Furthermore, at an even more basic level, it remains unclear to what degree spontaneous Ca2+ release and the appearance of DADs are deterministic, meaning reproducible under identical conditions, or inherently stochastic like nucleation in the physical context of phase transitions. In this thesis, we use and further develop a biologically detailed computational model to investigate basic aspects of TA in isolated heart cells (cardiac myocytes). Isolated cells can be obtained by enzymatic dissociation of heart tissue and studied experimentally using standard electrophysiological recording methods and confocal imaging of Ca2+ dynamics. Hence they provide a well controlled setting to investigate the generation of DADs under well controlled conditions. Our computational model captures essential aspects of the hierarchical architecture of ventricular myocytes, which consists of a large number of approximately 20,000 to 50,000 regularly spaced submicron regions containing clusters of 50-100 Ryanodine receptor (RyR) Ca2+ release channels. Each of those regions acts as a discrete "calcium release unit'' (CRU). Therefore our model allows us to address for the first time quantitatively the fundamental question of whether Ca2+ release, which is highly stochastic at the level of a single calcium release unit, is stochastic or deterministic at the whole cell level where the Ca 2+ signal is the summation of releases from a large number of units. Addressing this question is the focus of the first part of this thesis. Our results demonstrate that both the initiation and termination of TA are highly stochastic at the whole cell level due to the spatiotemporal organization of discrete release events into multiple Ca2+ waves. Our results allow us to characterize the probability distributions that govern the number of DADs preceding a triggered action potential and the number of triggered

  11. Towards the Physics of Calcium Signalling in Plants

    PubMed Central

    Vaz Martins, Teresa; Evans, Matthew J.; Woolfenden, Hugh C.; Morris, Richard J.

    2013-01-01

    Calcium is an abundant element with a wide variety of important roles within cells. Calcium ions are inter- and intra-cellular messengers that are involved in numerous signalling pathways. Fluctuating compartment-specific calcium ion concentrations can lead to localised and even plant-wide oscillations that can regulate downstream events. Understanding the mechanisms that give rise to these complex patterns that vary both in space and time can be challenging, even in cases for which individual components have been identified. Taking a systems biology approach, mathematical and computational techniques can be employed to produce models that recapitulate experimental observations and capture our current understanding of the system. Useful models make novel predictions that can be investigated and falsified experimentally. This review brings together recent work on the modelling of calcium signalling in plants, from the scale of ion channels through to plant-wide responses to external stimuli. Some in silico results that have informed later experiments are highlighted. PMID:27137393

  12. Bioceramics of calcium orthophosphates.

    PubMed

    Dorozhkin, Sergey V

    2010-03-01

    A strong interest in use of ceramics for biomedical applications appeared in the late 1960's. Used initially as alternatives to metals in order to increase a biocompatibility of implants, bioceramics have become a diverse class of biomaterials, presently including three basic types: relatively bioinert ceramics, bioactive (or surface reactive) and bioresorbable ones. Furthermore, any type of bioceramics could be porous to provide tissue ingrowth. This review is devoted to bioceramics prepared from calcium orthophosphates, which belong to the categories of bioresorbable and bioactive compounds. During the past 30-40 years, there have been a number of major advances in this field. Namely, after the initial work on development of bioceramics that was tolerated in the physiological environment, emphasis was shifted towards the use of bioceramics that interacted with bones by forming a direct chemical bond. By the structural and compositional control, it became possible to choose whether the bioceramics of calcium orthophosphates was biologically stable once incorporated within the skeletal structure or whether it was resorbed over time. At the turn of the millennium, a new concept of calcium orthophosphate bioceramics, which is able to regenerate bone tissues, has been developed. Current biomedical applications of calcium orthophosphate bioceramics include replacements for hips, knees, teeth, tendons and ligaments, as well as repair for periodontal disease, maxillofacial reconstruction, augmentation and stabilization of the jawbone, spinal fusion and bone fillers after tumor surgery. Potential future applications of calcium orthophosphate bioceramics will include drug-delivery systems, as well as they will become effective carriers of growth factors, bioactive peptides and/or various types of cells for tissue engineering purposes.

  13. Dissection of calcium signaling events in exocrine secretion.

    PubMed

    Ambudkar, Indu S

    2011-07-01

    The secretion of fluid and electrolytes by salivary gland acinar cells requires the coordinated regulation of multiple ion channel and transporter proteins, signaling components, and water transport. Importantly, neurotransmitter stimulated increase in the cytosolic free [Ca(2+)] ([Ca(2+)](i)) is critical for the regulation of salivary gland secretion as it regulates several major ion fluxes that together establish the sustained osmotic gradient to drive fluid secretion. The mechanisms that act to modulate these increases in [Ca(2+)](i) are therefore central to the process of salivary fluid secretion. Such modulation involves membrane receptors for neurotransmitters, as well as mechanisms that mediate intracellular Ca(2+) release, and Ca(2+) entry, as well as those that maintain cellular Ca(2+) homeostasis. Together, these mechanisms determine the spatial and temporal aspects of the [Ca(2+)](i) signals that regulate fluid secretion. Molecular cloning of these transporters and channels as well as development of mice lacking these proteins has established the physiological significance of key components that are involved in regulating [Ca(2+)](i) in salivary glands. This review will discuss these important studies and the findings which have led to resolution of the Ca(2+) signaling mechanisms that determine salivary gland fluid secretion.

  14. Rare Events

    DTIC Science & Technology

    2009-10-01

    terrorists are likely to acquire and use WMDs over the next ten years. • Provide means to target areas, entities and persons facilitating adver - sary WMD...complicated and unpredictable to begin with, but also that human adver - saries (unlike physical disasters) will react and adapt to our planning to try to make...virulent vaccine strain (Keim et al., 2001). The latter might not be regarded as a bioterrorism event, even though it caused seven deaths and incited

  15. Local calcium changes regulate the length of growth cone filopodia.

    PubMed

    Cheng, Su; Geddis, Matthew S; Rehder, Vincent

    2002-03-01

    Previous studies have demonstrated that the free intracellular calcium concentration ([Ca(2+)](i)) in growth cones can act as an important regulator of growth cone behavior. Here we investigated whether there is a spatial and temporal correlation between [Ca(2+)](i) and one particular aspect of growth cone behavior, namely the regulation of growth cone filopodia. Calcium was released from the caged compound NP-EGTA (o-nitrophenyl EGTA tetrapotassium salt) to simulate a signaling event in the form of a transient increase in [Ca(2+)](i). In three different experimental paradigms, we released calcium either globally (within an entire growth cone), regionally (within a small area of the lamellipodium), or locally (within a single filopodium). We demonstrate that global photolysis of NP-EGTA in growth cones caused a transient increase in [Ca(2+)](i) throughout the growth cone and elicited subsequent filopodial elongation that was restricted to the stimulated growth cone. Pharmacological blockage of either calmodulin or the Ca(2+)-dependent phosphatase, calcineurin, inhibited the effect of uncaging calcium, suggesting that these enzymes are acting downstream of calcium. Regional uncaging of calcium in the lamellipodium caused a regional increase in [Ca(2+)](i), but induced filopodial elongation on the entire growth cone. Elevation of [Ca(2+)](i) locally within an individual filopodium resulted in the elongation of only the stimulated filopodium. These findings suggest that the effect of an elevation of [Ca(2+)](i) on filopodial behavior depends on the spatial distribution of the calcium signal. In particular, calcium signals within filopodia can cause filopodial length changes that are likely a first step towards directed filopodial steering events seen during pathfinding in vivo.

  16. Calcium Phosphates and Human Beings

    NASA Astrophysics Data System (ADS)

    Dorozhkin, Sergey V.

    2006-05-01

    This article describes the general importance of calcium phosphates for human beings. The basic information on the structure and chemical properties of the biologically relevant calcium phosphates is summarized. Basic facts on the natural occurrence and the industrial use of natural calcium phosphates are discussed. Fundamental details on the presence of calcium phosphates in major calcified tissues (bones and teeth) of humans and mammals, as well as on biomaterials made of calcium phosphates are discussed. The article will be of value for chemistry teachers for expansion of their general background and point the students' attention to the rapidly growing topic of bone-substituting biomaterials.

  17. The effect of preceding biopsy on complete endoscopic resection in rectal carcinoid tumor.

    PubMed

    Lee, Sang Pyo; Sung, In-Kyung; Kim, Jeong Hwan; Lee, Sun-Young; Park, Hyung Seok; Shim, Chan Sup

    2014-04-01

    Biopsy of rectal carcinoid tumor is commonly taken before endoscopic resection. However the preceding biopsy can inhibit complete resection by causing blurred tumor border and fibrosis of the tissue. The objective of the study was to investigate the effect of preceding biopsy on complete endoscopic resection in rectal carcinoid tumor. It was also determined if rectal carcinoid tumors can be macroscopically distinguished by endoscopy. We reviewed retrospectively the records of patients with rectal carcinoid tumor who had undergone an endoscopic treatment at our hospital, during a 7-yr period. The resection margin was clear in 57 of 98 cases. The preceding biopsy was taken in 57 cases and the biopsy was significantly associated with the risk of incomplete tumor resection (OR, 3.696; 95% CI, 1.528-8.938, P = 0.004). In 95.9% of the cases, it was possible to suspect a carcinoid tumor by macroscopic appearance during initial endoscopy. The preceding biopsy may disturb complete resection of rectal carcinoid tumor. In most cases, the carcinoid tumor could be suspected by macroscopic appearance. Therefore the preceding biopsy is not essential, and it may be avoided for the complete resection.

  18. No Evidence of Conpopulation Sperm Precedence between Allopatric Populations of House Mice

    PubMed Central

    Firman, Renée C.; Simmons, Leigh W.

    2014-01-01

    Investigations into the evolution of reproductive barriers have traditionally focused on closely related species, and the prevalence of conspecific sperm precedence. The effectiveness of conspecific sperm precedence at limiting gene exchange between species suggests that gametic isolation is an important component of reproductive isolation. However, there is a paucity of tests for evidence of sperm precedence during the earlier stages of divergence, for example among isolated populations. Here, we sourced individuals from two allopatric populations of house mice (Mus domesticus) and performed competitive in vitro fertilisation assays to test for conpopulation sperm precedence specifically at the gametic level. We found that ova population origin did not influence the outcome of the sperm competitions, and thus provide no evidence of conpopulation or heteropopulation sperm precedence. Instead, we found that males from a population that had evolved under a high level of postcopulatory sexual selection consistently outcompeted males from a population that had evolved under a relatively lower level of postcopulatory sexual selection. We standardised the number of motile sperm of each competitor across the replicate assays. Our data therefore show that competitive fertilizing success was directly attributable to differences in sperm fertilizing competence. PMID:25295521

  19. An improved car-following model with multiple preceding cars' velocity fluctuation feedback

    NASA Astrophysics Data System (ADS)

    Guo, Lantian; Zhao, Xiangmo; Yu, Shaowei; Li, Xiuhai; Shi, Zhongke

    2017-04-01

    In order to explore and evaluate the effects of velocity variation trend of multiple preceding cars used in the Cooperative Adaptive Cruise Control (CACC) strategy on the dynamic characteristic, fuel economy and emission of the corresponding traffic flow, we conduct a study as follows: firstly, with the real-time car-following (CF) data, the close relationship between multiple preceding cars' velocity fluctuation feedback and the host car's behaviors is explored, the evaluation results clearly show that multiple preceding cars' velocity fluctuation with different time window-width are highly correlated to the host car's acceleration/deceleration. Then, a microscopic traffic flow model is proposed to evaluate the effects of multiple preceding cars' velocity fluctuation feedback in the CACC strategy on the traffic flow evolution process. Finally, numerical simulations on fuel economy and exhaust emission of the traffic flow are also implemented by utilizing VT-micro model. Simulation results prove that considering multiple preceding cars' velocity fluctuation feedback in the control strategy of the CACC system can improve roadway traffic mobility, fuel economy and exhaust emission performance.

  20. An Ocean Acidification Pulse in the Pre-onset Carbon Isotope Excursion Preceding the Paleocene-Eocene Thermal Maximum

    NASA Astrophysics Data System (ADS)

    Robinson, M. M.; Self-Trail, J. M.; Willard, D. A.; Stassen, P.; Spivey, W.

    2015-12-01

    The Paleocene-Eocene Thermal Maximum (PETM; ~55.5 Ma) is recognized globally in marine sediments by a carbonate dissolution zone, the extinction or turnover of benthic taxa, and a radiation of planktic excursion taxa, all accompanied by a rapid-onset, negative carbon isotope excursion (CIE). The cause and nature of the massive carbon release leading to this extreme climate event remains under debate. Regardless of cause, the environmental and ecosystem changes centered on the PETM are the subject of much study because they provide an analog to modern deteriorating conditions associated with the ongoing rise in atmospheric carbon dioxide. We present evidence from sediments of the South Dover Bridge core, deposited on the U.S. mid-Atlantic shelf, for an ocean acidification event in the latest Paleocene that coincides with a relatively small (-2‰) negative carbon isotope excursion (CIE) that precedes the larger (-4‰) Paleocene-Eocene CIE onset. Planktic foraminifers during this pre-onset event (POE) show post-deposition dissolution in which the coarsely cancellate and muricate wall textures characteristic of many Late Paleocene species have been dissolved away, leaving smooth, thin-walled specimens often with collapsed chambers. In addition, we document biotic responses in benthic, planktic, and terrestrial communities to the POE, including shifts in foraminifer and pollen assemblages and adaptations in calcareous nannofossil species in response to environmental perturbations. A complete recovery is evident between the POE and CIE in both the carbon isotopic signal and in the biotic response, providing additional evidence not only for a pulsed carbon release, but also for a more rapid rate of carbon release than is suggested by a single pulse over a longer period of time. The timing, nature and magnitude of ecological changes during the less extreme POE shallow water acidification event may help to define the ecological tipping point of shallow marine ecosystems.

  1. Can short-term heart rate variability be used to monitor fentanyl-midazolam induced changes in ANS preceding respiratory depression?

    PubMed

    Smith, Anne-Louise; Owen, Harry; Reynolds, Karen J

    2015-06-01

    Opioids have an occasional but high-risk side effect of respiratory depression. The detection of critical respiratory depression usually occurs after the event. Earlier detection would be beneficial in preventing increased morbidity and mortality of 0.01 % patients receiving analgesic opioids. Airway patency during inspiration requires vagal modulation. Regulation of the cardiovascular and respiratory centres may be coupled with a central mechanism that is indirectly measurable with heart rate variability (HRV). While opioids tend to increase parasympathetic tone, a decrease in airway stability could be due to a decrease in respiratory parasympathetic activity. Sympathetic arousal generated by apneic events may separately be recognised with short-term HRV. This pilot observational study examined the dynamic sympathovagal changes during fentanyl-midazolam induced respiratory depression on 10 subjects scheduled for minor surgery. A selection of HRV indices, able to work over sub-minute periods on non-stationary signals, were applied including a range of less common indices. Three analyses tested the effects: post-fentanyl, preceding the first central depression, and preceding obstruction of the upper airway. Statistical significance was assessed with overlap of bootstrap percentile confidence intervals for the median. A decrease in total variability, Lomb Total using the Lomb-Scargle method, is a positive finding for short-term HRV use in this study. No significant change before critical respiratory events was observed in traditional, spectral power, respiratory or other indices. One index, PolVar20, indicated a burst of sympathetic activity preceding respiratory depression similar to sleep apnoea arousals that restore airway patency. Before its usefulness in early detection of airway tone can be determined, PolVar20 requires further work: a statistical method for highly skewed distributions, auto adjustment for baseline variability, and detecting a range of

  2. Calcium signaling in taste cells.

    PubMed

    Medler, Kathryn F

    2015-09-01

    The sense of taste is a common ability shared by all organisms and is used to detect nutrients as well as potentially harmful compounds. Thus taste is critical to survival. Despite its importance, surprisingly little is known about the mechanisms generating and regulating responses to taste stimuli. All taste responses depend on calcium signals to generate appropriate responses which are relayed to the brain. Some taste cells have conventional synapses and rely on calcium influx through voltage-gated calcium channels. Other taste cells lack these synapses and depend on calcium release to formulate an output signal through a hemichannel. Beyond establishing these characteristics, few studies have focused on understanding how these calcium signals are formed. We identified multiple calcium clearance mechanisms that regulate calcium levels in taste cells as well as a calcium influx that contributes to maintaining appropriate calcium homeostasis in these cells. Multiple factors regulate the evoked taste signals with varying roles in different cell populations. Clearly, calcium signaling is a dynamic process in taste cells and is more complex than has previously been appreciated. This article is part of a Special Issue entitled: 13th European Symposium on Calcium.

  3. Learning from Mount St. Helens: Catastrophic Events as Educational Opportunities.

    ERIC Educational Resources Information Center

    Anderson, Jeremy

    1987-01-01

    Maintains that the study of catastrophic events should be given temporary precedence over the normal curriculum in order to help students understand the causes, consequences, and recovery alternatives, deal with trauma, and allay fear of recurrence and feelings of helplessness. Uses the May 1980 eruption of Mount St. Helens to demonstrate how…

  4. Fruit Calcium: Transport and Physiology

    PubMed Central

    Hocking, Bradleigh; Tyerman, Stephen D.; Burton, Rachel A.; Gilliham, Matthew

    2016-01-01

    Calcium has well-documented roles in plant signaling, water relations and cell wall interactions. Significant research into how calcium impacts these individual processes in various tissues has been carried out; however, the influence of calcium on fruit ripening has not been thoroughly explored. Here, we review the current state of knowledge on how calcium may impact the development, physical traits and disease susceptibility of fruit through facilitating developmental and stress response signaling, stabilizing membranes, influencing water relations and modifying cell wall properties through cross-linking of de-esterified pectins. We explore the involvement of calcium in hormone signaling integral to the physiological mechanisms behind common disorders that have been associated with fruit calcium deficiency (e.g., blossom end rot in tomatoes or bitter pit in apples). This review works toward an improved understanding of how the many roles of calcium interact to influence fruit ripening, and proposes future research directions to fill knowledge gaps. Specifically, we focus mostly on grapes and present a model that integrates existing knowledge around these various functions of calcium in fruit, which provides a basis for understanding the physiological impacts of sub-optimal calcium nutrition in grapes. Calcium accumulation and distribution in fruit is shown to be highly dependent on water delivery and cell wall interactions in the apoplasm. Localized calcium deficiencies observed in particular species or varieties can result from differences in xylem morphology, fruit water relations and pectin composition, and can cause leaky membranes, irregular cell wall softening, impaired hormonal signaling and aberrant fruit development. We propose that the role of apoplasmic calcium-pectin crosslinking, particularly in the xylem, is an understudied area that may have a key influence on fruit water relations. Furthermore, we believe that improved knowledge of the calcium

  5. Predictive Physiological Anticipation Preceding Seemingly Unpredictable Stimuli: A Meta-Analysis

    PubMed Central

    Mossbridge, Julia; Tressoldi, Patrizio; Utts, Jessica

    2012-01-01

    This meta-analysis of 26 reports published between 1978 and 2010 tests an unusual hypothesis: for stimuli of two or more types that are presented in an order designed to be unpredictable and that produce different post-stimulus physiological activity, the direction of pre-stimulus physiological activity reflects the direction of post-stimulus physiological activity, resulting in an unexplained anticipatory effect. The reports we examined used one of two paradigms: (1) randomly ordered presentations of arousing vs. neutral stimuli, or (2) guessing tasks with feedback (correct vs. incorrect). Dependent variables included: electrodermal activity, heart rate, blood volume, pupil dilation, electroencephalographic activity, and blood oxygenation level dependent (BOLD) activity. To avoid including data hand-picked from multiple different analyses, no post hoc experiments were considered. The results reveal a significant overall effect with a small effect size [fixed effect: overall ES = 0.21, 95% CI = 0.15–0.27, z = 6.9, p < 2.7 × 10−12; random effects: overall (weighted) ES = 0.21, 95% CI = 0.13–0.29, z = 5.3, p < 5.7 × 10−8]. Higher quality experiments produced a quantitatively larger effect size and a greater level of significance than lower quality studies. The number of contrary unpublished reports that would be necessary to reduce the level of significance to chance (p > 0.05) was conservatively calculated to be 87 reports. We explore alternative explanations and examine the potential linkage between this unexplained anticipatory activity and other results demonstrating meaningful pre-stimulus activity preceding behaviorally relevant events. We conclude that to further examine this currently unexplained anticipatory activity, multiple replications arising from different laboratories using the same methods are necessary. The cause of this anticipatory activity, which undoubtedly lies within the realm of natural

  6. DISTILLATION OF CALCIUM

    DOEpatents

    Barton, J.

    1954-07-27

    This invention relates to an improvement in the process for the purification of caicium or magnesium containing an alkali metal as impurity, which comprises distiiling a batch of the mixture in two stages, the first stage distillation being carried out in the presence of an inert gas at an absolute pressure substantially greater than the vapor pressure of calcium or maguesium at the temperature of distillation, but less than the vaper pressure at that temperature of the alkali metal impurity so that only the alkali metal is vaporized and condensed on a condensing surface. A second stage distilso that substantially only the calcium or magnesium distills under its own vapor pressure only and condenses in solid form on a lower condensing surface.

  7. Nutrition in calcium nephrolithiasis

    PubMed Central

    2013-01-01

    Idiopathic calcium nephrolithiasis is a multifactorial disease with a complex pathogenesis due to genetic and environmental factors. The importance of social and health effects of nephrolithiasis is further highlighted by the strong tendency to relapse of the disease. Long-term prospective studies show a peak of disease recurrence within 2–3 years since onset, 40-50% of patients have a recurrence after 5 years and more than 50-60% after 10 years. International nutritional studies demonstrated that nutritional habits are relevant in therapy and prevention approaches of nephrolithiasis. Water, right intake of calcium, low intake of sodium, high levels of urinary citrate are certainly important for the primary and secondary prevention of nephrolithiasis. In this review is discussed how the correction of nutritional mistakes can reduce the incidence of recurrent nephrolithiasis. PMID:23634702

  8. Complexometric Determination of Calcium

    NASA Astrophysics Data System (ADS)

    Nielsen, S. Suzanne

    Ethylenediaminetetraacetate (EDTA) complexes with numerous mineral ions, including calcium and magnesium. This reaction can be used to determine the amount of these minerals in a sample by a complexometric titration. Endpoints in the titration are detected using indicators that change color when they complex with mineral ions. Calmagite and eriochrome black T (EBT) are such indicators that change from blue to pink when they complex with calcium and magnesium. In the titration of a mineral-containing solution with EDTA, the solution turns from pink to blue at the endpoint with either indicator. The pH affects a complexometric EDTA titration in several ways, and must be carefully controlled. A major application of EDTA titration is testing the hardness of water, for which the method described is an official one (Standard Methods for the Examination of Water and Wastewater, Method 2340C; AOAC Method 920.196).

  9. Synthesis of calcium superoxide

    NASA Technical Reports Server (NTRS)

    Rewick, R. T.; Blucher, W. G.; Estacio, P. L.

    1972-01-01

    Efforts to prepare Ca(O2) sub 2 from reactions of calcium compounds with 100% O3 and with O(D-1) atoms generated by photolysis of O3 at 2537 A are described. Samples of Ca(OH) sub 2, CaO, CaO2, Ca metal, and mixtures containing suspected impurities to promote reaction have been treated with excess O3 under static and flow conditions in the presence and absence of UV irradiation. Studies with KO2 suggest that the superoxide anion is stable to radiation at 2537 A but reacts with oxygen atoms generated by the photolysis of O3 to form KO3. Calcium superoxide is expected to behave in an analogous.

  10. Availability of calcium from skim milk, calcium sulfate and calcium carbonate for bone mineralization in pigs.

    PubMed

    Pointillart, A; Coxam, V; Sève, B; Colin, C; Lacroix, C H; Guéguen, L

    2000-01-01

    Dairy products provide abundant, accessible calcium for humans, while some calcium sulfate-rich mineral waters could provide appreciable amounts of calcium. But there is little evidence that this calcium is as available as milk calcium for making bone. The availability of calcium was studied by monitoring bone parameters in 2-month-old pigs fed restricted amounts of calcium (70% RDA) for 2.5 months. The 3 main (> or = 50% Ca intake) Ca sources were either CaCO3 or CaSO4 or skim milk powder (29% of the diet). The bones of the pigs fed the "milk" diet had higher (P < 0.01) ash contents, breaking strength and density (DEXA) than those of the two others groups, in which the bone values were similar. Thus, the calcium provided by a diet containing milk appears to ensure better bone mineralization than do calcium salts included in a non-milk diet. The calcium restriction may have enhanced some milk properties to stimulate calcium absorption in these young, rapidly growing pigs.

  11. A novel car following model considering average speed of preceding vehicles group

    NASA Astrophysics Data System (ADS)

    Sun, Dihua; Kang, Yirong; Yang, Shuhong

    2015-10-01

    In this paper, a new car following model is presented by considering the average speed effect of preceding vehicles group in cyber-physical systems (CPS) environment. The effect of this new consideration upon the stability of traffic flow is examined through linear stability analysis. A modified Korteweg-de Vries (mKdV) equation was derived via nonlinear analysis to describe the propagating behavior of traffic density wave near the critical point. Good agreement between the simulation and the analytical results shows that average speed of preceding vehicles group leads to the stabilization of traffic systems, and thus can efficiently suppress the emergence of traffic jamming.

  12. Relationship Type and Sexual Precedence: Their Associations With Characteristics of Sexual Assault Perpetrators and Incidents

    PubMed Central

    Wegner, Rhiana; Pierce, Jennifer; Abbey, Antonia

    2015-01-01

    Although most sexual assaults are committed by men who know their victims, few researchers have considered how characteristics of perpetrators and incidents differ depending on the victim–perpetrator relationship. This study addresses this gap with a community sample of 204 men who reported committing a sexually aggressive act in an audio computer-assisted self-interview. 2 (Relationship Type: Committed vs. Casual) × 2 (Sexual Precedence: Yes vs. No) ANOVAs revealed significant main effects of relationship type and sexual precedence associated with individual difference and incident characteristics. These findings demonstrate the importance of developing theories and prevention programs tailored for different relationship contexts. PMID:25288595

  13. Progress through precedent: Going where no helicopter simulator has gone before

    NASA Technical Reports Server (NTRS)

    Adams, Richard J.

    1992-01-01

    Helicopter simulators have been approved by means of special exemption; there are no FAA standards for simulators used in training or airmen Certification checking. The fixed-wing industry provides a precedent which can be used for expediting implementation of helicopter simulators. The analysis in this paper is founded on the experience with that precedent and is driven by a clear definition of helicopter user needs for (1) improved training at lower cost, (2) more comprehensive emergency training at lower risk, (3) increased fidelity of transition and instrument training compared with low-cost aircraft alternatives, and (4) certification credit for improved simulator training.

  14. A model of propagating calcium-induced calcium release mediated by calcium diffusion

    PubMed Central

    1989-01-01

    The effect of sudden local fluctuations of the free sarcoplasmic [Ca++]i in cardiac cells on calcium release and calcium uptake by the sarcoplasmic reticulum (SR) was calculated with the aid of a simplified model of SR calcium handling. The model was used to evaluate whether propagation of calcium transients and the range of propagation velocities observed experimentally (0.05-15 mm s(-1)) could be predicted. Calcium fluctuations propagate by virtue of focal calcium release from the SR, diffusion through the cytosol (which is modulated by binding to troponin and calmodulin and sequestration by the SR), and subsequently induce calcium release from adjacent release sites of the SR. The minimal and maximal velocities derived from the simulation were 0.09 and 15 mm s(-1) respectively. The method of solution involved writing the diffusion equation as a difference equation in the spatial coordinates. Thus, coupled ordinary differential equations in time with banded coefficients were generated. The coupled equations were solved using Gear's sixth order predictor-corrector algorithm for stiff equations with reflective boundaries. The most important determinants of the velocity of propagation of the calcium waves were the diastolic [Ca++]i, the rate of rise of the release, and the amount of calcium released from the SR. The results are consistent with the assumptions that calcium loading causes an increase in intracellular calcium and calcium in the SR, and an increase in the amount and rate of calcium released. These two effects combine to increase the propagation velocity at higher levels of calcium loading. PMID:2738577

  15. Calcium bioavailability and kinetics of calcium ascorbate and calcium acetate in rats.

    PubMed

    Cai, Jianwei; Zhang, Qinmin; Wastney, Meryl E; Weaver, Connie M

    2004-01-01

    The objective was to investigate the bioavailability and mechanism of calcium absorption of calcium ascorbate (ASC) and calcium acetate (AC). A series of studies was performed in adult Sprague-Dawley male rats. In the first study, each group of rats (n = 10/group) was assigned to one of the five test meals labeled with (45)Ca: (i) 25 mg calcium as heated ASC or (ii) unheated ASC, (iii) 25 mg calcium as unheated AC, (iv) 3.6 mg Ca as unheated ASC, or (v) unheated AC. Femur uptake indicated better calcium bioavailability from ASC than AC at both calcium loads. A 5-min heat treatment partly reduced bioavailability of ASC. Kinetic studies were performed to further investigate the mechanism of superior calcium bioavailability from ASC. Two groups of rats (n = 10/group) received oral doses of 25 mg Ca as ASC or AC. Each dose contained 20 micro Ci (45)Ca. Two additional groups of rats (n = 10/group) received an intravenous injection (iv) of 10 micro Ci (45)Ca after receiving an unlabeled oral dose of 25 mg calcium as ASC or AC. Sequential blood samples were collected over 48 hrs. Urine and fecal samples were collected every 12 hrs for 48 hrs and were analyzed for total calcium and (45)Ca content. Total calcium and (45)Ca from serum, urine, and feces were fitted by a compartment kinetics model with saturable and nonsaturable absorption pathways by WinSAAM (Windows-based Simulation Analysis and Modeling). The difference in calcium bioavailability between the two salts was due to differences in saturable rather than passive intestinal absorption and not to endogenous secretion or calcium deposition rate. The higher bioavailability of calcium ascorbate was due to a longer transit time in the small intestine compared with ASC.

  16. Calcium signalling and calcium channels: evolution and general principles.

    PubMed

    Verkhratsky, Alexei; Parpura, Vladimir

    2014-09-15

    Calcium as a divalent cation was selected early in evolution as a signaling molecule to be used by both prokaryotes and eukaryotes. Its low cytosolic concentration likely reflects the initial concentration of this ion in the primordial soup/ocean as unicellular organisms were formed. As the concentration of calcium in the ocean subsequently increased, so did the diversity of homeostatic molecules handling calcium. This includes the plasma membrane channels that allowed the calcium entry, as well as extrusion mechanisms, i.e., exchangers and pumps. Further diversification occurred with the evolution of intracellular organelles, in particular the endoplasmic reticulum and mitochondria, which also contain channels, exchanger(s) and pumps to handle the homeostasis of calcium ions. Calcium signalling system, based around coordinated interactions of the above molecular entities, can be activated by the opening of voltage-gated channels, neurotransmitters, second messengers and/or mechanical stimulation, and as such is all-pervading pathway in physiology and pathophysiology of organisms.

  17. Elemental calcium intake associated with calcium acetate/calcium carbonate in the treatment of hyperphosphatemia

    PubMed Central

    Wilson, Rosamund J; Copley, J Brian

    2017-01-01

    Background Calcium-based and non-calcium-based phosphate binders have similar efficacy in the treatment of hyperphosphatemia; however, calcium-based binders may be associated with hypercalcemia, vascular calcification, and adynamic bone disease. Scope A post hoc analysis was carried out of data from a 16-week, Phase IV study of patients with end-stage renal disease (ESRD) who switched to lanthanum carbonate monotherapy from baseline calcium acetate/calcium carbonate monotherapy. Of the intent-to-treat population (N=2520), 752 patients with recorded dose data for calcium acetate (n=551)/calcium carbonate (n=201) at baseline and lanthanum carbonate at week 16 were studied. Elemental calcium intake, serum phosphate, corrected serum calcium, and serum intact parathyroid hormone levels were analyzed. Findings Of the 551 patients with calcium acetate dose data, 271 (49.2%) had an elemental calcium intake of at least 1.5 g/day at baseline, and 142 (25.8%) had an intake of at least 2.0 g/day. Mean (95% confidence interval [CI]) serum phosphate levels were 6.1 (5.89, 6.21) mg/dL at baseline and 6.2 (6.04, 6.38) mg/dL at 16 weeks; mean (95% CI) corrected serum calcium levels were 9.3 (9.16, 9.44) mg/dL and 9.2 (9.06, 9.34) mg/dL, respectively. Of the 201 patients with calcium carbonate dose data, 117 (58.2%) had an elemental calcium intake of at least 1.5 g/day, and 76 (37.8%) had an intake of at least 2.0 g/day. Mean (95% CI) serum phosphate levels were 5.8 (5.52, 6.06) mg/dL at baseline and 5.8 (5.53, 6.05) mg/dL at week 16; mean (95% CI) corrected serum calcium levels were 9.7 (9.15, 10.25) mg/dL and 9.2 (9.06, 9.34) mg/dL, respectively. Conclusion Calcium acetate/calcium carbonate phosphate binders, taken to control serum phosphate levels, may result in high levels of elemental calcium intake. This may lead to complications related to calcium balance. PMID:28182142

  18. Effect of diazepam on calcium translocation during physiological muscle fatigue.

    PubMed

    Bianchi, C P; Narayan, S R

    1984-10-01

    Stimulation of frog sartorius muscle at 1 Hz leads to an initial positive staircase during the first 120 twitches and is followed by a negative staircase. There is a net calcium influx into two distinct compartments within the muscle during the positive staircase. The two compartments are separated by measuring the calcium extracted from muscles soaked in strontium-Ringer for 15 min and the calcium remaining in the muscle. A net gain of extractable Ca++ (0.32 mumol/g wet wt.) and residual Ca++ (0.18 mumol/g) is observed during positive staircase. A loss in residual Ca++, a gain in extractable Ca++ and a net loss of Ca++ (0.09 mumol/g) to the bathing medium occur during the period preceding physiological muscle fatigue (60 to 120 twitches). Diazepam (EC50, 5.6 X 10(-6) M) causes a marked reduction in the latent period and increases the rate constant 2.6 times the control value for physiological muscle fatigue. A net loss of 0.31 mumol/g of Ca++ to the bathing medium occurs during the interval between 60 and 120 twitches. Diazepam increases net Ca++ efflux 3.5-fold during this interval when compared to control muscles. Diazepam does not affect the Ca++ gained during the positive staircase but accelerates the loss of calcium from the residual and the extractable compartments during the initial phase of physiological muscle fatigue. Physiological muscle fatigue is attributed to an accumulation of calcium in the transverse tubular network and an uncoupling of the muscle action potential from contraction.

  19. Lipid peroxidation, calcium, iron, and TCDD toxicity in rats

    SciTech Connect

    Al-Bayati, Z.A.F.

    1986-01-01

    2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) has been studied as a prototype of halogenated aromatic hydrocarbons. Previous studies have shown that TCDD enhances hepatic lipid peroxidation. This study on TCDD administration to rats was conducted to: measure induction of lipid peroxidation in hepatic and extrahepatic tissues; compare lipid peroxidation between sexes; determine the contributions of H/sub 2/O/sub 2/ and other reactive oxygen species and associated enzymes on hepatic lipid peroxidation: determine the role of iron in TCDD-induced lipid peroxidation; and investigate the relationship between TCDD-induced alterations in lipid peroxidation, calcium homeostasis, reduced glutathione content (GSH) and selenium-dependent glutathione peroxidase activity (GSH-Px). The results demonstrated that TCDD induces changes in microsomal lipid peroxidation in hepatic and extrahepatic tissues. The rates of microsomal lipid peroxidation in male rats were less than in microsomes from female rats. TCDD treatment produced a significant increase in lipid peroxidation which preceded an increase in whole homogenate and mitochondrial calcium content, but paralleled an increase in microsomal calcium content. TCDD treatment produced dose and time dependent decreases in hepatic GSH content and GSH-Px activity in female rats. H/sub 2/O/sub 2/ and possibly hydroxyl radical and singlet oxygen are involved in TCDD-induced hepatic microsomal lipid peroxidation. The results support the hypothesis that the toxicity of TCDD and its lack of tissue selectivity in male and female rats may be due in part to lipid peroxidation. Lipid peroxidation may alter membrane permeability to calcium and lead to sequestration of calcium.

  20. Geophysical events

    NASA Astrophysics Data System (ADS)

    This is a summary of SEAN Bulletin, 13(2), February 29, 1988, a publication of the Smithsonian Institution's Scientific Event Alert Network. The complete bulletin is available in the microfiche edition of Eos as a microfiche supplement or as a paper reprint. For the microfiche, order document E88-002 at $2.50 (U.S.) by writing to AGU Orders, 2000 Florida Avenue, N.W., Washington, DC 20009 or by calling toll free on 800-424-2488. For the paper reprint, order SEAN Bulletin (giving volume and issue numbers and issue date) through the same address; the price is $3.50 for one copy of each issue number for those who do not have a deposit account, $2 for those who do; additional copies of each issue number are $ 1.

  1. Like Extinction, Latent Inhibition of Conditioned Fear in Mice Is Blocked by Systemic Inhibition of L-Type Voltage-Gated Calcium Channels

    ERIC Educational Resources Information Center

    Blouin, Ashley M.; Cain, Chris K.; Barad, Mike

    2004-01-01

    Having recently shown that extinction of conditioned fear depends on L-type voltage-gated calcium channels (LVGCCs), we have been seeking other protocols that require this unusual induction mechanism. We tested latent inhibition (LI) of fear, because LI resembles extinction except that cue exposures precede, rather than follow, cue-shock pairing.…

  2. Ultrastructural localisation of calcium deposits in pig ovarian follicles.

    PubMed

    Rozinek, J; Rajmon, R; Petr, J; Rohlík, J; Jeseta, M; Sedmíková, M; Rehák, D; Jílek, F

    2006-01-01

    Calcium intracellular signaling regulates many intracellular events including oocyte maturation. This signaling is strongly dependent on the influx of calcium ions from extracellular spaces and on the state of intracellular calcium stores. In this study, intracellular calcium deposits were detected in follicle-enclosed pig oocytes using the combined oxalate-pyroantimonate method. These deposits were observed in the nucleus, the mitochondria, the cytoplasm, and on the surface of lipid droplets. The amount of calcium deposits was expressed as a percentage of the area of the respective cellular compartment, which is covered with calcium deposits on ultrathin sections. The distribution of calcium deposits in oocytes changed during folliculogenesis. The amount of calcium deposits in nuclei (1.11% of the area of oocyte nuclei) and cytoplasm (1.02%) in oocytes from secondary and early antral follicles (0.90% nuclei; 0.99% cytoplasm) is significantly lower (P < 0.05) than the amount of calcium deposits in these compartments in oocytes from primary follicles (2.51% nuclei; 2.34% cytoplasm) or antral follicles with growing oocyte (2.91% nuclei; 2.21% cytoplasm). The amount of calcium deposits in mitochondria of oocytes from primary follicles (1.27%) or antral follicles with growing oocyte (1.14%) is significantly lower (P < 0.05) than in the nucleus (2.51% in oocytes from primary follicles; 2.91% in growing oocytes from antral follicles) or cytoplasm (2.34% in oocytes from primary follicles; 2.21% in growing oocytes from antral follicles). The amount of calcium deposits in the cytoplasm of fully-grown oocytes (1.46%) dropped to levels significantly lower (P < 0.05) than those observed in the oocyte nucleus (2.29%). On the basis of these data, we can conclude that the population of follicles on pig ovaries differs in the distribution and concentration of calcium deposits in oocytes, and these changes may be involved in the regulation of the meiotic competence of oocytes.

  3. Who should receive calcium and vitamin D supplementation?

    PubMed

    Verbrugge, Frederik H; Gielen, Evelien; Milisen, Koen; Boonen, Steven

    2012-09-01

    Combined calcium and vitamin D supplementation is recommended in the prevention and treatment of osteoporosis. Until recently, supplementation was perceived as harmless without adverse effects. However, recent meta-analyses have provided evidence suggesting that calcium supplements, whether or not in combination with vitamin D, may be associated with cardiovascular risks. Although this finding constitutes a safety signal that has to be taken seriously, these data have to be interpreted with some caution. Current data do not allow definite conclusions to be drawn, but require further independent confirmation, since in numerous large studies, combined calcium and vitamin D supplementation did not increase cardiovascular events, even in the most frail and elderly populations. Nevertheless, it seems appropriate to correct calcium deficiency preferably by enhancing dietary intake and to target supplementation on individuals at high risk of fracture or in whom calcium and vitamin D deficiency is highly prevalent. Other trials have shown an increased risk of falls and fractures with annual oral administration of high dose of vitamin D. Therefore, supplementation with more frequent, lower doses is preferred. Yet, the optimal dosing schedule is unknown and needs further study. In order to correct age-associated secondary hyperparathyroidism and to prevent osteoporotic fractures, a daily dose of 1,000-1,200 mg calcium and 800 IU vitamin D is recommended in elderly or institutionalised people, patients with established osteoporosis and individuals on glucocorticoids.

  4. Metabolic and Signaling Alterations in Dystrophin-Deficient Hearts Precede Overt Cardiomyopathy

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The cytoskeletal protein dystrophin has been implicated in hereditary and acquired forms of cardiomyopathy. However, much remains to be learned about the role of dystrophin in the heart. We hypothesized that the dystrophin-deficient heart displays early alterations in energy metabolism that precede ...

  5. Reduced Activation of Left Orbitofrontal Cortex Precedes Blocked Vocalization: A Magnetoencephalographic Study

    ERIC Educational Resources Information Center

    Sowman, Paul F.; Crain, Stephen; Harrison, Elisabeth; Johnson, Blake W.

    2012-01-01

    While stuttering is known to be characterized by anomalous brain activations during speech, very little data is available describing brain activations during stuttering. To our knowledge there are no reports describing brain activations that precede blocking. In this case report we present magnetoencephalographic data from a person who stutters…

  6. Application of the PRECEDE Model to Understanding Mental Health Promoting Behaviors in Hong Kong

    ERIC Educational Resources Information Center

    Mo, Phoenix K. H.; Mak, Winnie W. S.

    2008-01-01

    The burdens related to mental illness have been increasingly recognized in many countries. Nevertheless, research in positive mental health behaviors remains scarce. This study utilizes the Predisposing, Reinforcing, and Enabling Causes in Education Diagnosis and Evaluation (PRECEDE) model to identify factors associated with mental health…

  7. Parafoveal Processing of Word n + 2 during Reading: Do the Preceding Words Matter?

    ERIC Educational Resources Information Center

    Angele, Bernhard; Rayner, Keith

    2011-01-01

    We used the boundary paradigm (Rayner, 1975) to test two hypotheses that might explain why no conclusive evidence has been found for the existence of n + 2 preprocessing effects. In Experiment 1, we tested whether parafoveal processing of the second word to the right of fixation (n + 2) takes place only when the preceding word (n + 1) is very…

  8. Self-Efficacy, Goal Orientations and Learning Strategies as Mediators between Preceding and Subsequent Academic Achievement

    ERIC Educational Resources Information Center

    Diseth, Age

    2011-01-01

    High school grade point average (HSGPA), self-efficacy, goal orientations, learning strategies, and examination grade were measured in a sample of Norwegian undergraduate psychology students in order to investigate motives and strategies as mediators between preceding and subsequent academic achievement. Correlation analysis showed strong…

  9. 20 CFR 410.681 - Change of ruling or legal precedent.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 20 Employees' Benefits 2 2010-04-01 2010-04-01 false Change of ruling or legal precedent. 410.681 Section 410.681 Employees' Benefits SOCIAL SECURITY ADMINISTRATION FEDERAL COAL MINE HEALTH AND SAFETY ACT..., Administrative Review, Finality of Decisions, and Representation of Parties § 410.681 Change of ruling or...

  10. Effects of Age and Hearing Loss on Gap Detection and the Precedence Effect: Broadband Stimuli

    ERIC Educational Resources Information Center

    Roberts, Richard A.; Lister, Jennifer J.

    2004-01-01

    Older listeners with normal-hearing sensitivity and impaired-hearing sensitivity often demonstrate poorer-than-normal performance on tasks of speech understanding in noise and reverberation. Deficits in temporal resolution and in the precedence effect may underlie this difficulty. Temporal resolution is often studied by means of a gap-detection…

  11. Female Genital Cutting: Applying the PRECEDE-PROCEED Model To Understand the Incentives for the Practice.

    ERIC Educational Resources Information Center

    Dabbagh, Leila

    2002-01-01

    Reviews the practice of female circumcision and the significance of considering social, cultural, economic, and educational opportunities available to females in developing countries when creating intervention programs to help end this practice. The PRECEDE-PROCEED model is a tool that can assess various elements present in a girls' life that…

  12. Applying PRECEDE-PROCEED to Develop an Intuitive Eating Nondieting Approach to Weight Management Pilot Program

    ERIC Educational Resources Information Center

    Cole, Renee E.; Horacek, Tanya

    2009-01-01

    Objective: To describe the use of a consolidated version of the PRECEDE-PROCEED participatory program planning model to collaboratively design an intuitive eating program with Fort Drum military spouses tailored to their readiness to reject the dieting mentality and make healthful lifestyle modifications. Design: A consolidated version of…

  13. Age Differences in Understanding Precedent-Setting Decisions and Authorities' Responses to Violations of Deontic Rules

    ERIC Educational Resources Information Center

    Klaczynski, Paul A.

    2011-01-01

    To examine age trends in precedent-setting decisions and the effects of these decisions on perceptions of authorities, preadolescents and adolescents were presented with deontic rule infractions that occurred in the absence or presence of mitigating circumstances. In Study 1, in the absence of mitigating circumstances, adolescents recommended…

  14. 26 CFR 1.672(d)-1 - Power subject to condition precedent.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... the exercise of the power is subject to a precedent giving of notice or takes effect only after the... creates a trust for the benefit of his son and retains a power to revoke which takes effect only after the... not cause him to be treated as an owner with respect to ordinary income during the first 10 years...

  15. [Evaluation of severity of harm to health caused by trauma aggravating a preceding disease].

    PubMed

    Kapustin, A V

    2003-01-01

    A severity of damage made to the health condition by an injury aggravating a preceding pathology is under discussion. It was demonstrated that such criteria as the time period of temporary disablement as well as the permanent disablement ensure, with respect for clinical data, an objective assessment of a severity done to the health in the discussed cases.

  16. Using the PRECEDE Model for Causal Analysis of Bulimic Tendencies among Elite Women Swimmers.

    ERIC Educational Resources Information Center

    Benson, RoseAnn; Taub, Diane E.

    1993-01-01

    Describes a study of weight control techniques and bulimic tendencies among elite female participants in an Olympic Swimming Selection Meet. Results showed concern with thinness, body dissatisfaction, and unhealthy eating, dieting, and weight loss patterns among participants. Discusses the explanatory power of the PRECEDE model. (SM)

  17. 48 CFR 52.214-29 - Order of Precedence-Sealed Bidding.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 48 Federal Acquisition Regulations System 2 2011-10-01 2011-10-01 false Order of Precedence-Sealed Bidding. 52.214-29 Section 52.214-29 Federal Acquisition Regulations System FEDERAL ACQUISITION REGULATION...: Order of Precedence—Sealed Bidding (JAN 1986) Any inconsistency in this solicitation or contract...

  18. 48 CFR 52.214-29 - Order of Precedence-Sealed Bidding.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 48 Federal Acquisition Regulations System 2 2012-10-01 2012-10-01 false Order of Precedence-Sealed Bidding. 52.214-29 Section 52.214-29 Federal Acquisition Regulations System FEDERAL ACQUISITION REGULATION...: Order of Precedence—Sealed Bidding (JAN 1986) Any inconsistency in this solicitation or contract...

  19. 48 CFR 52.214-29 - Order of Precedence-Sealed Bidding.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 2 2010-10-01 2010-10-01 false Order of Precedence-Sealed Bidding. 52.214-29 Section 52.214-29 Federal Acquisition Regulations System FEDERAL ACQUISITION REGULATION...: Order of Precedence—Sealed Bidding (JAN 1986) Any inconsistency in this solicitation or contract...

  20. Ancient Uses of Meteoritic Metals as Precedent for Modern In-Situ Asteroid Mining

    NASA Astrophysics Data System (ADS)

    Mardon, Austin A.; Fawcett, Brett; Krispin, Daniel

    2016-05-01

    Given the strain on earth's supply of metal and the meteoritic content of meteorites, a prudent course would be to pursue in-situ asteroid mining of meteors for metal. There is a precedent for this going back to ancient Egypt; humans have always used the meteoritic content of meteorites to fashion everything from weapons to cosmetics.

  1. Postwar Era Precedents and the Ambivalent Quest for International Students at the University of Florida

    ERIC Educational Resources Information Center

    Terzian, Sevan G.; Osborne, Leigh Ann

    2006-01-01

    The number of international students studying at U.S. institutions of higher education in the 2003-2004 academic year dropped for the first time in more than three decades. New visa restrictions and international tensions in the wake of September 11, 2001, have been cited as central factors. This article identifies historical precedents from the…

  2. Effect of Personnel Change on Supreme Court Use of Precedent in Freedom of Expression Cases.

    ERIC Educational Resources Information Center

    Schwartz, Thomas A.; Warrick, Kathleen

    To test the findings of a 1981 study, which concluded that the Supreme Court of Chief Justice Warren Burger has attempted to reverse the liberal policies of the court presided over by Earl Warren by adopting a policy of ignoring precedent, a second study duplicated the earlier study's general research design, except that it focused on freedom of…

  3. Strategy Precedes Operational Effectiveness: Aligning High Graduation Rankings with Competitive Graduation Grade Point Averages

    ERIC Educational Resources Information Center

    Apprey, Maurice; Bassett, Kimberley C.; Preston-Grimes, Patrice; Lewis, Dion W.; Wood, Beverly

    2014-01-01

    Two pivotal and interconnected claims are addressed in this article. First, strategy precedes program effectiveness. Second, graduation rates and rankings are insufficient in any account of academic progress for African American students. In this article, graduation is regarded as the floor and not the ceiling, as it were. The ideal situation in…

  4. Events diary

    NASA Astrophysics Data System (ADS)

    2000-01-01

    as Imperial College, the Royal Albert Hall, the Royal College of Art, the Natural History and Science Museums and the Royal Geographical Society. Under the heading `Shaping the future together' BA2000 will explore science, engineering and technology in their wider cultural context. Further information about this event on 6 - 12 September may be obtained from Sandra Koura, BA2000 Festival Manager, British Association for the Advancement of Science, 23 Savile Row, London W1X 2NB (tel: 0171 973 3075, e-mail: sandra.koura@britassoc.org.uk ). Details of the creating SPARKS events may be obtained from creating.sparks@britassoc.org.uk or from the website www.britassoc.org.uk . Other events 3 - 7 July, Porto Alegre, Brazil VII Interamerican conference on physics education: The preparation of physicists and physics teachers in contemporary society. Info: IACPE7@if.ufrgs.br or cabbat1.cnea.gov.ar/iacpe/iacpei.htm 27 August - 1 September, Barcelona, Spain GIREP conference: Physics teacher education beyond 2000. Info: www.blues.uab.es/phyteb/index.html

  5. Theoretical aspects of calcium signaling

    NASA Astrophysics Data System (ADS)

    Pencea, Corneliu Stefan

    2001-08-01

    Experiments investigating intracellular calcium dynamics have revealed that calcium signals differentially affect a variety of intracellular processes, from fertilization and cell development and differentiation to subsequent cellular activity, ending with cell death. As an intracellular messenger, calcium transmits information within and between cells, thus regulating their activity. To control such a variety of processes, calcium signals have to be very flexible and also precisely regulated. The cell uses a calcium signaling ``toolkit'', where calcium ions can act in different contexts of space, amplitude and time. For different tasks, the cell selects the particular signal, or combination of signals, that triggers the appropriate physiological response. The physical foundations of such a versatile cellular signaling toolkit involving calcium are not completely understood, despite important experimental and theoretical progress made recently. The declared goal of this work is to investigate physical mechanisms on which the propagation of differential signals can be based. The dynamics of calcium near a cluster of inositol trisphosphate (IP3) activated calcium channels has been investigated analytically and numerically. Our work has demonstrated that clusters of different IP3 receptors can show similar bistable behavior, but differ in both the transient and long term dynamics. We have also investigated the conditions under which a calcium signal propagates between a pair of localized stores. We have shown that the propagation of the signal across a random distribution of such stores shows a percolation transition manifested in the shape of the wave front. More importantly, our work indicates that specific distribution of stores can be interpreted as calcium circuits that can perform important signal analyzing task, from unidirectional propagation and coincidence detection to a complete set of logic gates. We believe that phenomena like the ones described are

  6. Cardiovascular effects of calcium supplements.

    PubMed

    Reid, Ian R

    2013-07-05

    Calcium supplements reduce bone turnover and slow the rate of bone loss. However, few studies have demonstrated reduced fracture incidence with calcium supplements, and meta-analyses show only a 10% decrease in fractures, which is of borderline statistical and clinical significance. Trials in normal older women and in patients with renal impairment suggest that calcium supplements increase the risk of cardiovascular disease. To further assess their safety, we recently conducted a meta-analysis of trials of calcium supplements, and found a 27%-31% increase in risk of myocardial infarction, and a 12%-20% increase in risk of stroke. These findings are robust because they are based on pre-specified analyses of randomized, placebo-controlled trials and are consistent across the trials. Co-administration of vitamin D with calcium does not lessen these adverse effects. The increased cardiovascular risk with calcium supplements is consistent with epidemiological data relating higher circulating calcium concentrations to cardiovascular disease in normal populations. There are several possible pathophysiological mechanisms for these effects, including effects on vascular calcification, vascular cells, blood coagulation and calcium-sensing receptors. Thus, the non-skeletal risks of calcium supplements appear to outweigh any skeletal benefits, and are they appear to be unnecessary for the efficacy of other osteoporosis treatments.

  7. 21 CFR 184.1195 - Calcium citrate.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... acid with calcium hydroxide or calcium carbonate. It occurs as a fine white, odorless powder and... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Calcium citrate. 184.1195 Section 184.1195 Food... Specific Substances Affirmed as GRAS § 184.1195 Calcium citrate. (a) Calcium citrate...

  8. 21 CFR 184.1195 - Calcium citrate.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... acid with calcium hydroxide or calcium carbonate. It occurs as a fine white, odorless powder and... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Calcium citrate. 184.1195 Section 184.1195 Food... Specific Substances Affirmed as GRAS § 184.1195 Calcium citrate. (a) Calcium citrate...

  9. 21 CFR 573.260 - Calcium silicate.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 6 2013-04-01 2013-04-01 false Calcium silicate. 573.260 Section 573.260 Food and... Listing § 573.260 Calcium silicate. Calcium silicate, including synthetic calcium silicate, may be safely used as an anticaking agent in animal feed, provided that the amount of calcium silicate does...

  10. 21 CFR 573.260 - Calcium silicate.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 6 2014-04-01 2014-04-01 false Calcium silicate. 573.260 Section 573.260 Food and... Listing § 573.260 Calcium silicate. Calcium silicate, including synthetic calcium silicate, may be safely used as an anticaking agent in animal feed, provided that the amount of calcium silicate does...

  11. 21 CFR 573.260 - Calcium silicate.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 6 2012-04-01 2012-04-01 false Calcium silicate. 573.260 Section 573.260 Food and... Listing § 573.260 Calcium silicate. Calcium silicate, including synthetic calcium silicate, may be safely used as an anticaking agent in animal feed, provided that the amount of calcium silicate does...

  12. 21 CFR 573.260 - Calcium silicate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Calcium silicate. 573.260 Section 573.260 Food and... Listing § 573.260 Calcium silicate. Calcium silicate, including synthetic calcium silicate, may be safely used as an anticaking agent in animal feed, provided that the amount of calcium silicate does...

  13. 21 CFR 573.260 - Calcium silicate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 6 2011-04-01 2011-04-01 false Calcium silicate. 573.260 Section 573.260 Food and... Listing § 573.260 Calcium silicate. Calcium silicate, including synthetic calcium silicate, may be safely used as an anticaking agent in animal feed, provided that the amount of calcium silicate does...

  14. 21 CFR 184.1195 - Calcium citrate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... Specific Substances Affirmed as GRAS § 184.1195 Calcium citrate. (a) Calcium citrate (Ca3(C6H5O7)2·4H2O, CAS Reg. No. 813-0994-095) is the calcium salt of citric acid. It is prepared by neutralizing citric acid with calcium hydroxide or calcium carbonate. It occurs as a fine white, odorless powder...

  15. Geophysical events

    NASA Astrophysics Data System (ADS)

    This is a summary of SEAN Bulletin, 13 (6), June 30, 1988, a publication of the Smithsonian Institution's Scientific Event Alert Network. The complete bulletin is available in the microfiche edition of Eos as a microfiche supplement or as a paper reprint. For the microfiche, order document E88-005 at $2.50 (U.S.) by writing to AGU Orders, 2000 Florida Avenue, N.W., Washington, DC 20009 or by calling toll free on 800-424-2488. For the paper reprint, order SEAN Bulletin (giving volume and issue numbers and issue date) through the same address; the price is $3.50 for one copy of each issue number for those who do not have a deposit account, $2 for those who do; additional copies of each issue number are $ 1. Subscriptions to SEAN Bulletin are also available from AGU-Orders; the price is $18 for 12 monthly issues mailed to a U.S. address, $28 if mailed elsewhere, and must be prepaid. SEAN Bulletin is available on Kosmos. Type CHECK SEAN on Part A of Kosmos.

  16. Geophysical events

    NASA Astrophysics Data System (ADS)

    This is a summary of SEAN Bulletin, 25(10), October 31, 1988, a publication of the Smithsonian Institution's Scientific Event Alert Network. The complete bulletin is available in the microfiche edition of Eos as a microfiche supplement or as a paper reprint. For the microfiche, order document E88-010 at $2.50 (U.S.) by writing to AGU Orders, 2000 Florida Avenue, N.W., Washington, DC 20009 or by calling toll free on 800-424-2488. For the paper reprint, order SEAN Bulletin (giving volume and issue numbers and issue date) through the same address; the price is $3.50 for one copy of each issue number for those who do not have a deposit account, $2 for those who do; additional copies of each issue number are $ 1 . Subscriptions to SEAN Bulletin are also available from AGU-Orders; the price is $18 for 12 monthly issues mailed to a U.S. address, $28 if mailed elsewhere, and must be prepaid. SEAN Bulletin is available on Kosmos. Type CHECK SEAN on Part A of Kosmos

  17. Geophysical events

    NASA Astrophysics Data System (ADS)

    This is a summary of SEAN Bulletin, 13(3), March 31, 1988, a publication of the Smithsonian Institution's Scientific Event Alert Network. The complete bulletin is available in the microfiche edition of Eos as a microfiche supplement or as a paper reprint. For the microfiche, order document E88-002 at $2.50 (U.S.) by writing to AGU Orders, 2000 Florida Avenue, N.W., Washington, DC 20009 or by calling toll free on 800-424-2488. For the paper reprint, order SEAN Bulletin (giving volume and issue numbers and issue date) through the same address; the price is $3.50 for one copy of each issue number for those who do not have a deposit account, $2 for those who do; additional copies of each issue number are $1. Subscriptions to SEAN Bulletin are also available from AGU-Orders; the price is $18 for 12 monthly issues mailed to a U.S. address, $28 if mailed elsewhere, and must be prepaid.

  18. Geophysical events

    NASA Astrophysics Data System (ADS)

    This is a summary of SEAN Bulletin, 13 (7), July 31, 1988, a publication of the Smithsonian Institution's Scientific Event Alert Network. The complete bulletin is available in the microfiche edition of Eos as a microfiche supplement or as a paper reprint. For the microfiche, order document E88-007 at $2.50 (U.S.) by writing to AGU Orders, 2000 Florida Avenue, N.W., Washington, DC 20009 or by calling toll free on 800-424-2488. For the paper reprint, order SEAN Bulletin (giving volume and issue numbers and issue date) through the same address; the price is $3.50 for one copy of each issue number for those who do not have a deposit account, $2 for those who do; additional copies of each issue number are $1. Subscriptions to SEAN Bulletin are also available from AGU-Orders; the price is $18 for 12 monthly issues mailed to a U.S. address, $28 if mailed elsewhere, and must be prepaid. SEAN Bulletin is available on Kosmos. Type CHECK SEAN on Part A of Kosmos.

  19. Geophysical events

    NASA Astrophysics Data System (ADS)

    This is a summary of SEAN Bulletin, 13 (1), January 31, 1988, a publication of the Smithsonian Institution's Scientific Event Alert Network. The complete bulletin is available in the microfiche edition of Eos as a microfiche supplement or as a paper reprint. For the microfiche, order document E88-001 at $2.50 (U.S.) by writing to AGU Orders, 2000 Florida Avenue, N.W., Washington, DC 20009 or by calling toll free on 800-424-2488. For the paper reprint, order SEAN Bulletin (giving volume and issue numbers and issue date) through the same address; the price is $3.50 for one copy of each issue number for those who do not have a deposit account, $2 for those who do; additional copies of each issue number are $ 1. Subscriptions to SEAN Bulletin are also available from AGU Orders; the price is $18 for 12 monthly issues mailed to a U.S. address, $28 if mailed elsewhere, and must be prepaid.

  20. Geophysical events

    NASA Astrophysics Data System (ADS)

    This is a summary of SEAN Bulletin, 13(9), September 30, 1988, a publication of the Smithsonian Institution's Scientific Event Alert Network. The complete bulletin is available in the microfiche edition of Eos as a microfiche supplement or as a paper reprint. For the microfiche, order document E88-013 at $2.50 (U.S.) by writing to AGU Orders, 2000 Florida Avenue, N.W., Washington, DC 20009 or by calling toll free on 800-424-2488. For the paper reprint, order SEAN Bulletin (giving volume and issue numbers and issue date) through the same address; the price is $3.50 for one copy of each issue number for those who do not have a deposit account, $2 for those who do; additional copies of each issue number are $1. Subscriptions to SEAN Bulletin are also available from AGU-Orders; the price is $18 for 12 monthly issues mailed to a U.S. address, $28 if mailed elsewhere, and must be prepaid. SEAN Bulletin is available on Kosmos. Type CHECK SEAN on Part A of Kosmos.

  1. Geophysical events

    NASA Astrophysics Data System (ADS)

    This is a summary of SEAN Bulletin, 13 (5), May 31, 1988, a publication of the Smithsonian Institution's Scientific Event Alert Network. The complete bulletin is available in the microfiche edition of Eos as a microfiche supplement or as a paper reprint. For the microfiche, order document E88-004 at $2.50 (U.S.) by writing to AGU Orders, 2000 Florida Avenue, N.W., Washington, DC 20009 or by calling toll free on 800-424-2488. For the paper reprint, order SEAN Bulletin (giving volume and issue numbers and issue date) through the same address; the price is $3.50 for one copy of each issue number for those who do not have a deposit account, $2 for those who do; additional copies of each issue number are $ 1. Subscriptions to SEAN Bulletin are also available from AGU-Orders; the price is $18 for 12 monthly issues mailed to a U.S. address, $28 if mailed elsewhere, and must be prepaid. SEAN Bulletin is available on Kosmos. Type CHECK SEAN on Part A of Kosmos.

  2. Perturbation Analysis of Calcium, Alkalinity and Secretion during Growth of Lily Pollen Tubes

    PubMed Central

    Winship, Lawrence J.; Rounds, Caleb; Hepler, Peter K.

    2016-01-01

    Pollen tubes grow by spatially and temporally regulated expansion of new material secreted into the cell wall at the tip of the tube. A complex web of interactions among cellular components, ions and small molecule provides dynamic control of localized expansion and secretion. Cross-correlation studies on oscillating lily (Lilium formosanum Wallace) pollen tubes showed that an increase in intracellular calcium follows an increase in growth, whereas the increase in the alkaline band and in secretion both anticipate the increase in growth rate. Calcium, as a follower, is unlikely to be a stimulator of growth, whereas the alkaline band, as a leader, may be an activator. To gain further insight herein we reversibly inhibited growth with potassium cyanide (KCN) and followed the re-establishment of calcium, pH and secretion patterns as growth resumed. While KCN markedly slows growth and causes the associated gradients of calcium and pH to sharply decline, its removal allows growth and vital processes to fully recover. The calcium gradient reappears before growth restarts; however, it is preceded by both the alkaline band and secretion, in which the alkaline band is slightly advanced over secretion. Thus the pH gradient, rather than the tip-focused calcium gradient, may regulate pollen tube growth. PMID:28042810

  3. Precipitating Events in Adolescent Suicidal Crises: Exploring Stress-Reactive and Nonreactive Risk Profiles

    ERIC Educational Resources Information Center

    Hill, Ryan M.; Pettit, Jeremy W.; Green, Kelly L.; Morgan, Sharon T.; Schatte, Dawnelle J.

    2012-01-01

    Factors distinguishing adolescents who experienced a precipitating event in the week preceding a suicidal crisis from those who did not were examined. Among 130 suicidal inpatients (mean age = 15.01 years), those who experienced a precipitating event reported significantly lower depressive symptom scores, better perceived problem solving, less…

  4. 21 CFR 172.330 - Calcium pantothenate, calcium chloride double salt.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Calcium pantothenate, calcium chloride double salt..., calcium chloride double salt. The food additive calcium chloride double salt of calcium pantothenate may... information required by the Act, the following: (1) The name of the additive “calcium chloride double salt...

  5. 21 CFR 172.330 - Calcium pantothenate, calcium chloride double salt.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Calcium pantothenate, calcium chloride double salt..., calcium chloride double salt. The food additive calcium chloride double salt of calcium pantothenate may... information required by the Act, the following: (1) The name of the additive “calcium chloride double salt...

  6. 21 CFR 172.330 - Calcium pantothenate, calcium chloride double salt.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Calcium pantothenate, calcium chloride double salt..., calcium chloride double salt. The food additive calcium chloride double salt of calcium pantothenate may... information required by the Act, the following: (1) The name of the additive “calcium chloride double salt...

  7. 21 CFR 172.330 - Calcium pantothenate, calcium chloride double salt.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Calcium pantothenate, calcium chloride double salt..., calcium chloride double salt. The food additive calcium chloride double salt of calcium pantothenate may... information required by the Act, the following: (1) The name of the additive “calcium chloride double salt...

  8. 21 CFR 172.330 - Calcium pantothenate, calcium chloride double salt.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Calcium pantothenate, calcium chloride double salt... Dietary and Nutritional Additives § 172.330 Calcium pantothenate, calcium chloride double salt. The food additive calcium chloride double salt of calcium pantothenate may be safely used in foods for...

  9. Calcium transporters: From fields to the table

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Calcium transporters regulate calcium fluxes within cells. Plants, like all organisms, contain channels, pumps, and exchangers to carefully modulate intracellular calcium levels. This review presents a summary of the recent advances in cloning and characterizing of these transporters and highlight...

  10. Vitamin D, Calcium, and Bone Health

    MedlinePlus

    ... in Balance › Vitamin D, Calcium, and Bone Health Vitamin D, Calcium, and Bone Health March 2012 Download ... also helps keep your bones strong. Why are vitamin D and calcium important to bone health? Vitamin ...

  11. Impact of Calcium Signaling during Infection of Neisseria meningitidis to Human Brain Microvascular Endothelial Cells

    PubMed Central

    Asmat, Tauseef M.; Tenenbaum, Tobias; Jonsson, Ann-Beth

    2014-01-01

    The pili and outer membrane proteins of Neisseria meningitidis (meningococci) facilitate bacterial adhesion and invasion into host cells. In this context expression of meningococcal PilC1 protein has been reported to play a crucial role. Intracellular calcium mobilization has been implicated as an important signaling event during internalization of several bacterial pathogens. Here we employed time lapse calcium-imaging and demonstrated that PilC1 of meningococci triggered a significant increase in cytoplasmic calcium in human brain microvascular endothelial cells, whereas PilC1-deficient meningococci could not initiate this signaling process. The increase in cytosolic calcium in response to PilC1-expressing meningococci was due to efflux of calcium from host intracellular stores as demonstrated by using 2-APB, which inhibits the release of calcium from the endoplasmic reticulum. Moreover, pre-treatment of host cells with U73122 (phospholipase C inhibitor) abolished the cytosolic calcium increase caused by PilC1-expressing meningococci demonstrating that active phospholipase C (PLC) is required to induce calcium transients in host cells. Furthermore, the role of cytosolic calcium on meningococcal adherence and internalization was documented by gentamicin protection assay and double immunofluorescence (DIF) staining. Results indicated that chelation of intracellular calcium by using BAPTA-AM significantly impaired PilC1-mediated meningococcal adherence to and invasion into host endothelial cells. However, buffering of extracellular calcium by BAPTA or EGTA demonstrated no significant effect on meningococcal adherence to and invasion into host cells. Taken together, these results indicate that meningococci induce calcium release from intracellular stores of host endothelial cells via PilC1 and cytoplasmic calcium concentrations play a critical role during PilC1 mediated meningococcal adherence to and subsequent invasion into host endothelial cells. PMID:25464500

  12. Global precedence, spatial frequency channels, and the statistics of natural images.

    PubMed

    Hughes, H C; Nozawa, G; Kitterle, F

    1996-01-01

    A great deal of evidence suggests that early in processing, retinal images are filtered by parallel, spatial frequency selective channels. We attempt to incorporate this view of early vision with the principle of global precedence, which holds that Gestalt-like processes sensitive to global image configurations tend to dominate local feature processing in human pattern perception. Global precedence is inferred from the pattern of reaction times observed when visual patterns contain multiple cues at different levels of spatial scale. Specifically, it is frequently observed that global processing times are largely unaffected by conflicting local cues, but local processing times are substantially lengthened by conflicting global cues. The asymmetry of these effects suggests the dominant role of global configurations. Since global spatial information is effectively represented by low spatial frequencies, global precedence potentially implies a low frequency dominance. The thesis is that low spatial frequencies tend to be available before information carried by higher frequency bands, producing a coarse-to-fine temporal order in visual spatial perception. It is suggested that a variety of factors contribute to the "prior entry" of low frequency information, including the high contrast gain of the magnocellular pathway, the amplitude spectra typical of natural images, and inhibitory interactions between the parallel frequency-tuned channels. Evidence suggesting a close relationship between global precedence and spatial frequency channels is provided by observations that the essential features of the global precedence effect are obtained using patterns consisting of low and high frequency sinusoids. The hypothesis that these asymmetric interference effects are due to interactions between parallel spatial channels is supported by an analysis of reaction times (RTs), which shows that RTs to redundant low and high frequency cues produce less facilitation than predictions

  13. Major Minerals - Calcium, Magnesium, Phosphorus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Calcium, magnesium and phosphorus are essential elements critically important for the function of the musculoskeletal system, including the formation and transduction of energy and the maintenance of healthy bone. The major calcium concern for physically active healthy middle-aged adults is to consu...

  14. Electrochemical cell with calcium anode

    DOEpatents

    Cooper, John F.; Hosmer, Pamela K.; Kelly, Benjamin E.

    1979-01-01

    An electrochemical cell comprising a calcium anode and a suitable cathode in an alkaline electrolyte consisting essentially of an aqueous solution of an hydroxide and a chloride. Specifically disclosed is a mechanically rechargeable calcium/air fuel cell with an aqueous NaOH/NaCl electrolyte.

  15. Calcium Intake: A Lifelong Proposition.

    ERIC Educational Resources Information Center

    Amschler, Denise H.

    1985-01-01

    This article reviews the current problem of low calcium intake in the United States among all age groups, the role of calcium in the formation and maintenance of bone mass, and major factors influencing absorption. Osteoporosis is discussed, and current recommendations for Recommended Dietary allowance are provided. (Author/MT)

  16. Osteopenic disease in growing pigs: diagnostic methods using serum and urine calcium and phosphorus values, parathoromone assay, and bone analysis.

    PubMed

    Hagemoser, W A; Goff, J P; Sanderson, T P; Haynes, J S

    2000-11-01

    This research was performed to evaluate the utility of several serum and urine parameters as well as bone ash and plasma parathormone assay to diagnose and monitor diet-related osteopenia in growing pigs. Five diets were tested as follows: calcium-deficient, phosphorus-replete; moderate-deficiency of calcium and phosphorus; marked deficiency of calcium and phosphorus; calcium replete, phosphorus deficient; and vitamin D deficient. Parameters monitored included serum calcium and phosphorus as well as ratios of urine calcium to creatinine, phosphorus to creatinine, calcium to phosphorus, and percent fractional excretions of calcium and phosphorus. Plasma parathormone (PTH) levels were monitored in 2 of 3 experiments. Osteopenic bone differences at necropsy were evaluated by bone density, percent ash, ash per milliliter bone, calcium per milliliter bone, and phosphorus per milliliter bone. Marked change in urine mineral parameters, especially the calcium-to-phosphorus ratio, typically occurred within 1 to 2 days of treatment and preceded significant change in serum mineral or plasma PTH by 2 to 3 weeks. When monitored, plasma PTH levels were elevated following treatment, which confirms the hyperparathyroid state induced by the test diets. Significant differences in bone mineralization between control and treatment diets at necropsy were generally observed. The results of this study indicate that the analysis of urine minerals offers an early, noninvasive technique to investigate diet-associated osteopenic disease in growing pigs, which can be supported further by bone mineral analysis at postmortem using techniques herein described. Several urine mineral reference intervals for application to field investigations are included. Research into application of similar techniques to evaluate calcium and phosphorus homeostasis in pigs of all ages, including gestating and lactating gilts and sows, appears warranted.

  17. Event segmentation ability uniquely predicts event memory.

    PubMed

    Sargent, Jesse Q; Zacks, Jeffrey M; Hambrick, David Z; Zacks, Rose T; Kurby, Christopher A; Bailey, Heather R; Eisenberg, Michelle L; Beck, Taylor M

    2013-11-01

    Memory for everyday events plays a central role in tasks of daily living, autobiographical memory, and planning. Event memory depends in part on segmenting ongoing activity into meaningful units. This study examined the relationship between event segmentation and memory in a lifespan sample to answer the following question: Is the ability to segment activity into meaningful events a unique predictor of subsequent memory, or is the relationship between event perception and memory accounted for by general cognitive abilities? Two hundred and eight adults ranging from 20 to 79years old segmented movies of everyday events and attempted to remember the events afterwards. They also completed psychometric ability tests and tests measuring script knowledge for everyday events. Event segmentation and script knowledge both explained unique variance in event memory above and beyond the psychometric measures, and did so as strongly in older as in younger adults. These results suggest that event segmentation is a basic cognitive mechanism, important for memory across the lifespan.

  18. The bioavailability of calcium in spinach and calcium-oxalate to calcium-deficient rats.

    PubMed

    Kikunaga, S; Arimori, M; Takahashi, M

    1988-04-01

    We estimated the utilization of calcium in spinach and calcium-oxalate to calcium-deficient rats, and the effect of oxalic acid on absorption of dietary calcium by using calcium-deficient rats. The body weight gain of the calcium-deficient rats for 8 days receiving a calcium-deficient diet supplemented with raw-powdered spinach (R-sp), boiled-powdered spinach (B-sp), or calcium-oxalate (Ca-ox), and a control diet supplemented with oxalic acid (OX-C) were 4.8, 2.8, 4.9, and 5.1 g, respectively. The calcium content in the liver and kidney of the rats receiving R-sp, B-sp, Ca-ox, and OX-C diets significantly increased as compared with the calcium-deficient rats. Significant differences in the liver calcium levels were not observed among the rats receiving various additional diets, though the content in the kidneys of the rats receiving R-sp, B-sp, Ca-ox, and OX-C diets were 28.0, 21.5, 0.11, and 0.59 mg, respectively. An especially large amount of calcium was accumulated in the kidneys of the rats receiving R-sp and B-sp diets. The calcium concentration in the serum of the rats receiving Ca-ox and OX-C diets was higher than the calcium concentration in the serum of the R-sp, B-sp, and calcium-deficient rats. The calcium content in the left tibiae of the rats receiving Ca-ox and OX-C diets was higher than that of the rats receiving R-sp and B-sp diets. The breaking force of the right tibiae of the rats was highest in the OX-C group, and higher in the R-sp and Ca-ox groups than the breaking force of the right tibiae of the rats fed on B-sp diet. The alkaline phosphatase activity in the small intestines of the rats rose in the order of the R-sp, B-sp, and Ca-ox groups, although significant differences of the activity were not observed between the Ca-ox and the OX-C groups. The calcium retention of the rats receiving the calcium-deficient, R-sp, B-sp, Ca-ox, and OX-C diets was -18.5, 35.2, 25.6, 41.6, and 45.8%, respectively. About 35% of the calcium in the spinach was

  19. Semiparametric time-to-event modeling in the presence of a latent progression event.

    PubMed

    Rice, John D; Tsodikov, Alex

    2016-08-24

    In cancer research, interest frequently centers on factors influencing a latent event that must precede a terminal event. In practice it is often impossible to observe the latent event precisely, making inference about this process difficult. To address this problem, we propose a joint model for the unobserved time to the latent and terminal events, with the two events linked by the baseline hazard. Covariates enter the model parametrically as linear combinations that multiply, respectively, the hazard for the latent event and the hazard for the terminal event conditional on the latent one. We derive the partial likelihood estimators for this problem assuming the latent event is observed, and propose a profile likelihood-based method for estimation when the latent event is unobserved. The baseline hazard in this case is estimated nonparametrically using the EM algorithm, which allows for closed-form Breslow-type estimators at each iteration, bringing improved computational efficiency and stability compared with maximizing the marginal likelihood directly. We present simulation studies to illustrate the finite-sample properties of the method; its use in practice is demonstrated in the analysis of a prostate cancer data set.

  20. The prediction of postpartum depression: The role of the PRECEDE model and health locus of control

    PubMed Central

    Moshki, Mahdi; Kharazmi, Akram; Cheravi, Khadijeh; Beydokhti, Tahereh Baloochi

    2015-01-01

    Background: The main purpose of this study was to investigate the effect of the PRECEDE model and health locus of control (HLC) on postpartum depression. This study used the path analysis to test the pattern of causal relations through the correlation coefficients. Materials and Method: The participants included 230 pregnant women in the north-east of Iran who were selected by convenience sampling. To analyze data, Pearson correlation and path analysis were applied to examine the relationships between variables using SPSS 20 and LISREL 8.50software. Results: The result of path analysis showed that a positive correlation exists between predisposing (knowledge, internal HLC, powerful others HLC, chance HLC) enabling and reinforcing factors with postpartum depression by GHQ score (GFI = 1, RSMEA = 000). Conclusion: The current study supported the application of the PRECEDE model and HLC in understanding the promoting behaviors in mental health and demonstrated their relationships with postpartum depression. PMID:26288792

  1. Anomalous transport in fluid field with random waiting time depending on the preceding jump length

    NASA Astrophysics Data System (ADS)

    Zhang, Hong; Li, Guo-Hua

    2016-11-01

    Anomalous (or non-Fickian) transport behaviors of particles have been widely observed in complex porous media. To capture the energy-dependent characteristics of non-Fickian transport of a particle in flow fields, in the present paper a generalized continuous time random walk model whose waiting time probability distribution depends on the preceding jump length is introduced, and the corresponding master equation in Fourier-Laplace space for the distribution of particles is derived. As examples, two generalized advection-dispersion equations for Gaussian distribution and lévy flight with the probability density function of waiting time being quadratic dependent on the preceding jump length are obtained by applying the derived master equation. Project supported by the Foundation for Young Key Teachers of Chengdu University of Technology, China (Grant No. KYGG201414) and the Opening Foundation of Geomathematics Key Laboratory of Sichuan Province, China (Grant No. scsxdz2013009).

  2. Calcium in Plants

    PubMed Central

    WHITE, PHILIP J.; BROADLEY, MARTIN R.

    2003-01-01

    Calcium is an essential plant nutrient. It is required for various structural roles in the cell wall and membranes, it is a counter‐cation for inorganic and organic anions in the vacuole, and the cytosolic Ca2+ concentration ([Ca2+]cyt) is an obligate intracellular messenger coordinating responses to numerous developmental cues and environmental challenges. This article provides an overview of the nutritional requirements of different plants for Ca, and how this impacts on natural flora and the Ca content of crops. It also reviews recent work on (a) the mechanisms of Ca2+ transport across cellular membranes, (b) understanding the origins and specificity of [Ca2+]cyt signals and (c) characterizing the cellular [Ca2+]cyt‐sensors (such as calmodulin, calcineurin B‐like proteins and calcium‐dependent protein kinases) that allow plant cells to respond appropriately to [Ca2+]cyt signals. PMID:12933363

  3. Practical algorithms for algebraic and logical correction in precedent-based recognition problems

    NASA Astrophysics Data System (ADS)

    Ablameyko, S. V.; Biryukov, A. S.; Dokukin, A. A.; D'yakonov, A. G.; Zhuravlev, Yu. I.; Krasnoproshin, V. V.; Obraztsov, V. A.; Romanov, M. Yu.; Ryazanov, V. V.

    2014-12-01

    Practical precedent-based recognition algorithms relying on logical or algebraic correction of various heuristic recognition algorithms are described. The recognition problem is solved in two stages. First, an arbitrary object is recognized independently by algorithms from a group. Then a final collective solution is produced by a suitable corrector. The general concepts of the algebraic approach are presented, practical algorithms for logical and algebraic correction are described, and results of their comparison are given.

  4. Legal precedents regarding use and defensibility of risk assessment in Federal transportation of SNF and HLW

    SciTech Connect

    Bentz, E.J. Jr.; Bentz, C.B.; O`Hora, T.D.; Chen, S.Y.

    1997-04-01

    Risk assessment has become an increasingly important and essential tool in support of Federal decision-making regarding the handling, storage, disposal, and transportation of spent nuclear fuel (SNF) and high-level radioactive waste (HLW). This paper analyzes the current statutory and regulatory framework and related legal precedents with regard to SNF and HLW transportation. The authors identify key scientific and technical issues regarding the use and defensibility of risk assessment in Federal decision-making regarding anticipated shipments.

  5. Herpes zoster ophthalmicus progressing to encephalitis: beware pain preceding the rash.

    PubMed

    Nandi, Novoneel; Morris, Paul; Blundell, Adrian

    2013-07-12

    We present a challenging case in which the dermatomal pain associated with herpes zoster ophthalmicus preceded the cutaneous rash by several days. It thus highlights the need to consider this diagnosis among the differentials for severe unilateral headache in the elderly. The patient unfortunately progressed to develop encephalitis, an uncommon but serious complication of zoster reactivation and a reminder that this remains an important cause of morbidity and mortality in the elderly population.

  6. Application of the PRECEDE-PROCEED Planning Model in Designing an Oral Health Strategy

    PubMed Central

    Binkley, Catherine J.; Johnson, Knowlton W.

    2014-01-01

    Background Although the poor oral health of adults with intellectual and developmental disabilities (IDD) constitutes a significant health disparity in the United States, few interventions to date have produced lasting results. Moreover, there is minimal application of planning models to inform and design a theory-based strategy that has the potential to be effective and sustainable in this population. Methods The PRECEDE-PROCEED planning model is being used to design and evaluate an oral health strategy for adults with IDD. The PRECEDE component involves assessing social, epidemiological, behavioral, environmental, educational, and ecological factors that informed the development of an intervention with underlying social cognitive theory assumptions. The PROCEED component consists of pilot-testing and evaluating the implementation of the strategy, its impact on mediators and outcomes of the population under study. Results A The PRECEDE assessment and strategy design results are presented including a conceptual framework and oral health strategy that are linked to social cognitive theory and Health Action Process Approach. We have developed a strategy consisting of a planned actions, capacity building, environmental adaptations, and caregiver reinforcement within group homes. The strategy is designed to increase caregiver self-efficacy, outcome expectancies, and behavioral capability, and also to create environmental influences that will lead to improved self-care behavior of the adult with IDD. It is anticipated that this strategy will improve the oral health and quality of life, including respiratory health, of individuals with IDD. The planned PROCEED component of the planning model includes a description of an in-process pilot study to refine the oral health strategy, along with a future randomized controlled clinical trial to demonstrate its effectiveness. Conclusions The application of the PRECEDE-PROCEED planning model presented here demonstrates the

  7. Organizational precedents for ownership and management of decentralized renewable-energy systems

    SciTech Connect

    Meunier, R.; Silversmith, J.A.

    1981-03-01

    Three existing organizational types that meet the decentralization criteria of local consumer ownership and control - cooperatives, Rural Electric Cooperatives, and municipal utilities - are examined. These three organizational precedents are analyzed in terms of their histories, structures, legal powers, sources of capital, and social and political aspects. Examples of related experiments with renewable energy technologies are given, and inferences are drawn regarding the organizations' suitability as vehicles for future implementation of decentralized renewable energy systems.

  8. Vanishing bile duct syndrome and immunodeficiency preceding the diagnosis of Hodgkin lymphoma.

    PubMed

    Yeh, P; Lokan, J; Anantharajah, A; Grigg, A

    2014-12-01

    Vanishing bile duct syndrome (VBDS) in association with Hodgkin lymphoma (HL) is well described but not well understood. We report an unusual case of a 75-year-old patient presenting with biopsy-proven VBDS and immunodeficiency, without identifiable cause, which showed a waxing and waning course, culminating in the development of HL 18 months later. To our knowledge, this is the first adult case in which VBDS preceded the diagnosis of HL by such a long period.

  9. A Decrease in Temperature and Humidity Precedes Human Rhinovirus Infections in a Cold Climate.

    PubMed

    Ikäheimo, Tiina M; Jaakkola, Kari; Jokelainen, Jari; Saukkoriipi, Annika; Roivainen, Merja; Juvonen, Raija; Vainio, Olli; Jaakkola, Jouni J K

    2016-09-02

    Both temperature and humidity may independently or jointly contribute to the risk of human rhinovirus (HRV) infections, either through altered survival and spread of viruses in the environment or due to changes in host susceptibility. This study examined the relationship between short-term variations in temperature and humidity and the risk of HRV infections in a subarctic climate. We conducted a case-crossover study among conscripts (n = 892) seeking medical attention due to respiratory symptoms during their military training and identified 147 HRV cases by real-time PCR. An average temperature, a decline in daily ambient temperature and absolute humidity (AH) during the three preceding days of the onset (hazard period) and two reference periods (a week prior and after the onset) were obtained. The average daily temperature preceding HRV infections was -9.9 ± 4.9 °C and the average AH was 2.2 ± 0.9 g/m³. An average (odds ratios (OR) 1.07 (95% confidence interval (CI) 1.00-1.15)) and maximal (OR 1.08 (1.01-1.17)) change in temperature increased the risk of HRV infections by 8% per 1 °C decrease. An average (OR 1.20 (CI 1.03-1.40)) and maximal decrease (OR 1.13 (CI 0.96-1.34)) in AH increased the risk of HRV infection by 13% and 20% per 0.5 g/m³ decrease. A higher average temperature during the three preceding days was positively associated with HRV infections (OR 1.07 (CI 1.00-1.15)). A decrease rather than low temperature and humidity per se during the preceding few days increases the risk of HRV infections in a cold climate. The information is applicable to populations residing in cold climates for appropriate personal protection and prevention of adverse health effects.

  10. Effects of Age and Hearing Loss on Gap Detection and the Precedence Effect: Narrow-Band Stimuli

    ERIC Educational Resources Information Center

    Lister, Jennifer J.; Roberts, Richard A.

    2005-01-01

    Deficits in temporal resolution and/or the precedence effect may underlie part of the speech understanding difficulties experienced by older listeners in degraded acoustic environments. In a previous investigation, R. Roberts and J. Lister (2004) identified a positive correlation between measures of temporal resolution and the precedence effect,…

  11. A free calcium wave traverses the activating egg of the medaka, Oryzias latipes

    PubMed Central

    Gilkey, J. C.; Jaffe, L. F.; Ridgway, E. B.; Reynolds, G. T.

    1978-01-01

    Aequorin-injected eggs of the medaka (a fresh water fish) show an explosive rise in free calcium during fertilization, which is followed by a slow return to the resting level. Image intensification techniques now show a spreading wave of high free calcium during fertilization. The wave starts at the animal pole (where the sperm enters) and then traverses the egg as a shallow, roughly 20 degrees-wide band which vanishes at the antipode some minutes later. The peak free calcium concentration within this moving band is estimated to be about 30 microM (perhaps 100-1,000 times the resting level). Eggs activated by ionophore A23187 may show multiple initiation sites. The resulting multiple waves never spread through each other; rather, they fuse upon meeting so as to form spreading waves of compound origin. The fertilization wave is nearly independent of extracellular calcium because it is only slightly slowed (by perhaps 15%) in a medium containing 5 mM ethylene glycol-bis[beta-aminoethyl ether]N,N'-tetraacetic acid (EGTA) and no deliberately added calcium. It is also independent of the large cortical vesicles, which may be centrifugally displaced. Normally, however, it distinctly precedes the well-known wave of cortical vesicle exocytosis. We conclude that the fertilization wave in the medaka egg is propagated by calcium-stimulated calcium release, primarily from some internal sources other than the large cortical vesicles. A comparison of the characteristics of the exocytotic wave in the medaka with that in other eggs, particularly in echinoderm eggs, suggests that such a propagated calcium wave is a general feature of egg activation. PMID:10605450

  12. Limestone reaction in calcium aluminate cement–calcium sulfate systems

    SciTech Connect

    Bizzozero, Julien Scrivener, Karen L.

    2015-10-15

    This paper reports a study of ternary blends composed of calcium aluminate cement, calcium sulfate hemihydrate and limestone. Compressive strength tests and hydration kinetics were studied as a function of limestone and calcium sulfate content. The phase evolution and the total porosity were followed and compared to thermodynamic simulation to understand the reactions involved and the effect of limestone on these binders. The reaction of limestone leads to the formation of hemicarboaluminate and monocarboaluminate. Increasing the ratio between sulfate and aluminate decreases the extent of limestone reaction.

  13. Two sources of meaning in infant communication: preceding action contexts and act-accompanying characteristics

    PubMed Central

    Liszkowski, Ulf

    2014-01-01

    How do infants communicate before they have acquired a language? This paper supports the hypothesis that infants possess social–cognitive skills that run deeper than language alone, enabling them to understand others and make themselves understood. I suggested that infants, like adults, use two sources of extralinguistic information to communicate meaningfully and react to and express communicative intentions appropriately. In support, a review of relevant experiments demonstrates, first, that infants use information from preceding shared activities to tailor their comprehension and production of communication. Second, a series of novel findings from our laboratory shows that in the absence of distinguishing information from preceding routines or activities, infants use accompanying characteristics (such as prosody and posture) that mark communicative intentions to extract and transmit meaning. Findings reveal that before infants begin to speak they communicate in meaningful ways by binding preceding and simultaneous multisensory information to a communicative act. These skills are not only a precursor to language, but also an outcome of social–cognitive development and social experience in the first year of life. PMID:25092662

  14. Calcium dynamics in astrocyte processes during neurovascular coupling

    PubMed Central

    Otsu, Yo; Couchman, Kiri; Lyons, Declan G; Collot, Mayeul; Agarwal, Amit; Mallet, Jean-Maurice; Pfrieger, Frank W; Bergles, Dwight E; Charpak, Serge

    2015-01-01

    Enhanced neuronal activity in the brain triggers a local increase in blood flow, termed functional hyperemia, via several mechanisms, including calcium (Ca2+) signaling in astrocytes. However, recent in vivo studies have questioned the role of astrocytes in functional hyperemia because of the slow and sparse dynamics of their somatic Ca2+ signals and the absence of glutamate metabotropic receptor 5 in adults. Here, we reexamined their role in neurovascular coupling by selectively expressing a genetically encoded Ca2+ sensor in astrocytes of the olfactory bulb. We show that in anesthetized mice, the physiological activation of olfactory sensory neuron (OSN) terminals reliably triggers Ca2+ increases in astrocyte processes but not in somata. These Ca2+ increases systematically precede the onset of functional hyperemia by 1–2 s, reestablishing astrocytes as potential regulators of neurovascular coupling. PMID:25531572

  15. Macromolecular recognition directs calcium ions to coccolith mineralization sites.

    PubMed

    Gal, Assaf; Wirth, Richard; Kopka, Joachim; Fratzl, Peter; Faivre, Damien; Scheffel, André

    2016-08-05

    Many organisms form elaborate mineralized structures, constituted of highly organized arrangements of crystals and organic macromolecules. The localization of crystals within these structures is presumably determined by the interaction of nucleating macromolecules with the mineral phase. Here we show that, preceding nucleation, a specific interaction between soluble organic molecules and an organic backbone structure directs mineral components to specific sites. This strategy underlies the formation of coccoliths, which are highly ordered arrangements of calcite crystals produced by marine microalgae. On combining the insoluble organic coccolith scaffold with coccolith-associated soluble macromolecules in vitro, we found a massive accretion of calcium ions at the sites where the crystals form in vivo. The in vitro process exhibits profound similarities to the initial stages of coccolith biogenesis in vivo.

  16. Calcium ions facilitate body heat emission response to warming.

    PubMed

    Tkachenko, E Ya; Khramova, G M; Kozyreva, T V

    2015-01-01

    Involvement of various areas of the body surface in heat emission response to warming is characterized by a certain succession. The first response preceding the deep body temperature rise is dilation of ear skin vessels. Then, an increase in deep body temperature is counterbalanced by vascular reaction in the tail region, which plays the leading role in up-regulation of heat emission. Calcium ions accelerate the vascular response to warming in both regions, although they produce no effect on the maximum level of heat emission. Our findings confirm the involvement of Ca(2+)-dependent mechanisms in activation of the processes aimed at stabilization of body temperature in warm-blooded animals. The role of heat-sensitive TRPV1 ion channels determining modality of the temperature signal and direction of effector reactions is discussed.

  17. Measuring Algorithm for the Distance to a Preceding Vehicle on Curve Road Using On-Board Monocular Camera

    NASA Astrophysics Data System (ADS)

    Yu, Guizhen; Zhou, Bin; Wang, Yunpeng; Wun, Xinkai; Wang, Pengcheng

    2015-12-01

    Due to more severe challenges of traffic safety problems, the Advanced Driver Assistance Systems (ADAS) has received widespread attention. Measuring the distance to a preceding vehicle is important for ADAS. However, the existing algorithm focuses more on straight road sections than on curve measurements. In this paper, we present a novel measuring algorithm for the distance to a preceding vehicle on a curve road using on-board monocular camera. Firstly, the characteristics of driving on the curve road is analyzed and the recognition of the preceding vehicle road area is proposed. Then, the vehicle detection and distance measuring algorithms are investigated. We have verified these algorithms on real road driving. The experimental results show that this method proposed in the paper can detect the preceding vehicle on curve roads and accurately calculate the longitudinal distance and horizontal distance to the preceding vehicle.

  18. Should we prescribe calcium or vitamin D supplements to treat or prevent osteoporosis?

    PubMed

    Bolland, M J; Grey, A; Reid, I R

    2015-01-01

    Systematic reviews of randomized, controlled trials (RCTs) are considered the highest level of evidence to inform clinical practice. Meta-analyses of large RCTs of calcium and/or vitamin D supplements completed in the last 15 years provide strong evidence for clinical recommendations. These meta-analyses with data for > 50,000 older adults reported that calcium with or without vitamin D has only weak, inconsistent effects on fracture, and that vitamin D without calcium has no effect on fracture. Only one RCT of co-administered calcium and vitamin D in frail, institutionalized, elderly women with low dietary calcium intake and vitamin D levels showed significant reductions in fracture risk. These RCTs have also reported previously unrecognized adverse events of calcium supplements including kidney stones, myocardial infarction, hypercalcemia, and hospitalization with acute gastrointestinal symptoms. The small risk of these important adverse effects, together with the moderate risk of minor side-effects such as constipation, probably outweighs any benefits of calcium supplements on fracture. These data suggest the role for calcium and vitamin D supplements in osteoporosis management is very limited. Neither calcium nor vitamin D supplements should be recommended for fracture prevention in community-dwelling adults, although vitamin D should be considered for prevention of osteomalacia in at-risk individuals.

  19. Defoaming effect of calcium soap.

    PubMed

    Zhang, Hui; Miller, Clarence A; Garrett, Peter R; Raney, Kirk H

    2004-11-15

    The effect of calcium oleate on foam stability was studied for aqueous solutions of two commonly used surfactants (anionic and nonionic) under alkaline conditions in the absence of oil. For the anionic surfactant, defoaming by calcium oleate appears to involve two mechanisms. One is that oleate and calcium ions are presumably incorporated into the surfactant monolayers with a resulting decrease in the maximum of the disjoining pressure curve and therefore produces less stable thin films. The other is bridging of the films by calcium oleate particles. The latter mechanism was especially important in freshly made solutions where precipitation in the aqueous phase was still occurring when the foam was generated. Foams generated after aging (hours) when precipitation was nearly complete were more stable even though solution turbidities were greater. Foams of the nonionic surfactant were less stable than those of the anionic surfactant but were also destabilized by sufficient amounts of calcium oleate and exhibited a similar aging effect. A simplified model was developed for estimating the sodium oleate concentration at which precipitation commences in solutions of the anionic surfactant containing dissolved calcium. It includes enhancement of calcium content in the electrical double layers of the surfactant micelles. Predictions of the model were in agreement with experiment.

  20. Calcium homeostasis in diabetes mellitus.

    PubMed

    Heath, H; Lambert, P W; Service, F J; Arnaud, S B

    1979-09-01

    Experimentally diabetic rats have low serum 1,25-dihydroxyvitamin D, intestinal malabsorption of calcium, secondary hyperparathyroidism, and bone loss. To examine the hypothesis that abnormalities similar to those in the diabetic rat might explain human diabetic osteopenia, we studied calcium metabolism in 40 healthy control and 82 diabetic patients aged 18--75 yr [47 untreated: fasting plasma glucose (mean +/- SE), 267 +/- 8 mg/dl; 19 treated but hyperglycemic: glucose 305 +/- 24 mg/dl; 16 treated and in better control: glucose, 146 +/- 8 mg/dl]. Serum total calcium, ionic calcium, immunoreactive parathyroid hormone (Arnaud method, GP-1M and CH-12M antisera), 25-hydroxyvitamin D (Haddad method), and 1,25-dihydroxyvitamin D (Lambert method) concentrations were normal in all 3 groups of diabetics and were not significantly different from values in the control group. We determined absorption of calcium from the intestine by a double isotope method (100 mg Ca carrier; normal range, 40--80%) in 11 control and 13 untreated, uncontrolled diabetics (mean plasma glucose, 285 +/- 17 mg/dl). Absorption of calcium in controls was 60 +/- 3% and in diabetics was 56 +/- 3% (not significantly different). We have found no derangement of calcium metabolism in adults with insulin-requiring juvenile- and adult-onset diabetes regardless of treatment status. The experimental diabetic rat model does not appear to be useful for determining the pathogenesis of adult human diabetic osteopenia.

  1. Experimental models of renal calcium stones in rodents

    PubMed Central

    Bilbault, Héloïse; Haymann, Jean-Philippe

    2016-01-01

    In human nephrolithiasis, most stones are containing calcium and are located within urinary cavities; they may contain monohydrate calcium oxalate, dihydrate calcium oxalate and/or calcium phosphates in various proportion. Nephrolithiasis may also be associated with nephrocalcinosis, i.e., crystal depositions in tubular lumen and/or interstitium, an entity which suggests specific pathological processes. Several rodents models have been developed in order to study the pathophysiology of intrarenal crystal formation. We review here calcium rodent models classified upon the presence of nephrolithiasis and/or nephrocalcinosis. As rodents are not prone to nephrolithiasis, models require the induction of a long standing hypercalciuria or hyperoxaluria (thus explaining the very few studies reported), conversely to nephrocalcinosis which may occur within hours or days. Whereas a nephrotoxicity leading to tubular injury and regeneration appears as a critical event for crystal retention in nephrocalcinosis models, surprisingly very little is known about the physiopathology of crystal attachment to urothelium in nephrolithiasis. Creating new models of nephrolithiasis especially in different genetic mice strains appears an important challenge in order to unravel the early mechanisms of urinary stone formation in papilla and fornices. PMID:26981444

  2. Creating Special Events

    ERIC Educational Resources Information Center

    deLisle, Lee

    2009-01-01

    "Creating Special Events" is organized as a systematic approach to festivals and events for students who seek a career in event management. This book looks at the evolution and history of festivals and events and proceeds to the nuts and bolts of event management. The book presents event management as the means of planning, organizing, directing,…

  3. Calcium intake and risk of cardiovascular disease: a review of prospective studies and randomized clinical trials.

    PubMed

    Wang, Lu; Manson, JoAnn E; Sesso, Howard D

    2012-04-01

    The potential effects of inadequate or excessive calcium supply on cardiovascular disease (CVD) are receiving growing attention. We review experimental, epidemiologic, and clinical evidence regarding the role of calcium intake in the development of CVD in adults. In vitro and in vivo laboratory studies have shown that calcium may affect the risk of developing CVD through multiple mechanisms including blood cholesterol, insulin secretion and sensitivity, vasodilation, inflammatory profile, thrombosis, obesity, and vascular calcification. A number of prospective epidemiologic studies have examined the relationship between dietary calcium intake and CVD incidence or mortality in middle-aged and older adults. The results were inconsistent, and the pooled data do not strongly support a significant effect of greater dietary calcium intake on the risk of coronary artery disease (CAD) or stroke. Only a few prospective studies have examined calcium supplement use in association with risk of CVD. The pooled data show no significant benefits of calcium supplement use in reducing the risk of CAD or stroke. No randomized clinical trial has specifically tested the effect of calcium supplementation on CVD as its primary endpoint. Secondary analyses in existing trials to date suggest a neutral effect of calcium (with or without vitamin D) supplements on CVD events, but do not allow for a definitive conclusion. A large percentage of Americans, particularly older adults, fail to meet the US recommendations for optimal calcium intake and are encouraged to increase daily calcium consumption. More prospective cohort studies and large-scale randomized trials are needed to further evaluate the risks or benefits of calcium supplementation on CVD endpoints as the primary pre-specified outcome.

  4. Calcium signals in olfactory neurons.

    PubMed

    Tareilus, E; Noé, J; Breer, H

    1995-11-09

    Laser scanning confocal microscopy in combination with the fluorescent calcium indicators Fluo-3 and Fura-Red was employed to estimate the intracellular concentration of free calcium ions in individual olfactory receptor neurons and to monitor temporal and spatial changes in the Ca(2+)-level upon stimulation. The chemosensory cells responded to odorants with a significant increase in the calcium concentration, preferentially in the dendritic knob. Applying various stimulation paradigma, it was found that in a population of isolated cells, subsets of receptor neurons display distinct patterns of responsiveness.

  5. Preinspiratory calcium rise in putative pre-Bötzinger complex astrocytes

    PubMed Central

    Okada, Yasumasa; Sasaki, Takuya; Oku, Yoshitaka; Takahashi, Naoya; Seki, Megumi; Ujita, Sakiko; Tanaka, Kenji F; Matsuki, Norio; Ikegaya, Yuji

    2012-01-01

    The neural inspiratory activity originates from a ventrolateral medullary region called the pre-Bötzinger complex (preBötC), yet the mechanism underlying respiratory rhythmogenesis is not completely understood. Recently, the role of not only neurons but astrocytes in the central respiratory control has attracted considerable attention. Here we report our discovery that an intracellular calcium rise in a subset of putative astrocytes precedes inspiratory neuronal firing in rhythmically active slices. Functional calcium imaging from hundreds of preBötC cells revealed that a subset of putative astrocytes exhibited rhythmic calcium elevations preceding inspiratory neuronal activity with a time lag of approximately 2 s. These preinspiratory putative astrocytes maintained their rhythmic activities even during the blockade of neuronal activity with tetrodotoxin, whereas the rhythm frequency was lowered and the intercellular phases of these rhythms were decoupled. In addition, optogenetic stimulation of preBötC putative astrocytes induced firing of inspiratory neurons. These findings raise the possibility that astrocytes in the preBötC are actively involved in respiratory rhythm generation in rhythmically active slices. PMID:22777672

  6. Climatological assessment of recent severe weather events

    SciTech Connect

    Changnon, D.; Changnon, S.A.

    1997-11-01

    A climatological assessment of a series of exceptionally severe and damaging storms during 1991-1994 was pursued to put these events and their frequency and intensity/severity into a temporal perspective. The severe weather events were assessed according to the damage they caused. Insurance-derived measures of property and crop losses due to weather were used in this study; these measures adjust individual storm losses to changing socioeconomic conditions. Two methods were used to assess the events: (1) a comparative analysis of event frequency, losses and intensity with those in the preceding 40 years, and (2) a comparison of temporal variations of the 1949-1994 events with fluctuations in population, cyclonic activity, and temperatures. The results showed that the 1991-1994 property losses ranked high in number and amount of loss. However, storm intensity was found to be higher in the 1950s. The temporal distributions of the catastrophes and crop losses were well related to North American cyclonic activity, and when cyclonic activity, U.S. mean temperatures, and population were combined, they explained 865 of the variability found in the frequency of catastrophes during 1949-1994. The results suggest that, although the severe weather events in 1991-1994 were exceptionally high in frequency and losses, much of the loss was a result of the ever increasing target at risk. 9 refs., 7 figs., 1 tab.

  7. The Effects of a Calcium-Rich Pre-Exercise Meal on Biomarkers of Calcium Homeostasis in Competitive Female Cyclists: A Randomised Crossover Trial

    PubMed Central

    Haakonssen, Eric C.; Ross, Megan L.; Knight, Emma J.; Cato, Louise E.; Nana, Alisa; Wluka, Anita E.; Cicuttini, Flavia M.; Wang, Bing H.; Jenkins, David G.; Burke, Louise M.

    2015-01-01

    Cycling is recognised as a sport in which there is a high incidence of poor bone health. Sweat calcium losses may contribute to this. Purpose To examine whether a calcium-rich pre-exercise meal attenuates exercise-induced perturbations of bone calcium homeostasis caused by maintenance of sweat calcium losses. Methods Using a randomized, counterbalanced crossover design, 32 well-trained female cyclists completed two 90 min cycling trials separated by 1 day. Exercise trials were preceded 2 hours by either a calcium-rich (1352 ± 53 mg calcium) dairy based meal (CAL) or a control meal (CON; 46 ± 7 mg calcium). Blood was sampled pre-trial; pre-exercise; and immediately, 40 min, 100 min and 190 min post-exercise. Blood was analysed for ionized calcium and biomarkers of bone resorption (Cross Linked C-Telopeptide of Type I Collagen (CTX-I), Cross Linked C-Telopeptide of Type II Collagen (CTX-II), Parathyroid Hormone (PTH), and bone formation (Procollagen I N-Terminal Propeptide (PINP)) using the established enzyme-linked immunosorbent assay technique. Results PTH and CTX-I increased from pre-exercise to post-exercise in both conditions but was attenuated in CAL (p < 0.001). PTH was 1.55 [1.20, 2.01] times lower in CAL immediately post-exercise and 1.45 [1.12, 1.88] times lower at 40 min post-exercise. CTX-I was 1.40 [1.15, 1.70] times lower in CAL at immediately post-exercise, 1.30 [1.07, 1.57] times lower at 40 min post-exercise and 1.22 [1.00, 1.48] times lower at 190 min post-exercise (p < 0.05). There was no significant interaction between pre-exercise meal condition and time point for CTX-II (p = 0.732) or PINP (p = 0.819). Conclusion This study showed that a calcium-rich pre-exercise breakfast meal containing ~1350 mg of calcium consumed ~90 min before a prolonged and high intensity bout of stationary cycling attenuates the exercise induced rise in markers of bone resorption – PTH and CTX-I. Trial Registration Australian New Zealand Clinical Trials Registry

  8. Effects of DDT on the calcium transport and thymidine uptake of bovine lymphocytes

    SciTech Connect

    McCabe, M.; Yin-Foo, D.

    1986-10-01

    It is known that organochlorine compounds in the environment present risks which may be related to an interference with calcium metabolism. The evidence in favor of a role for intracellular calcium levels as signals for the initiation of cell division is summarized by Metcalfe et al., and forms the basis for a calcium hypothesis for the control of cell growth. Lymphocytes undergoing transformation provide evidence for an involvement of calcium in the steps preceding mitogenic activation which occur within 20 hours of exposure to a mitogen. It has been suspected for some time that the incidence of lymphomas and leukemias may be higher in farming populations with significant past exposure to several organochlorine insecticides. It is also known that immune suppression can provoke an increase in the incidence of certain cancers, although whether this is an example of (lack of) immune surveillance for potential cancer cells or of some less direct mechanism such as a reduced resistance to a viral infection, is still unclear. For these reasons it is important to know whether DDT and other chemically related organochlorine compounds modulate calcium levels within lymphocytes, and if so whether this modulation relates to the observed effects of these compounds on lymphocyte mitogenesis. Such studies may also be of some value in providing a clue as to the relationship between chemically induced leukemias and DDT exposure.

  9. The calcium sensor Copine-6 regulates spine structural plasticity and learning and memory

    PubMed Central

    Reinhard, Judith R.; Kriz, Alexander; Galic, Milos; Angliker, Nico; Rajalu, Mathieu; Vogt, Kaspar E.; Ruegg, Markus A.

    2016-01-01

    Hippocampal long-term potentiation (LTP) represents the cellular response of excitatory synapses to specific patterns of high neuronal activity and is required for learning and memory. Here we identify a mechanism that requires the calcium-binding protein Copine-6 to translate the initial calcium signals into changes in spine structure. We show that Copine-6 is recruited from the cytosol of dendrites to postsynaptic spine membranes by calcium transients that precede LTP. Cpne6 knockout mice are deficient in hippocampal LTP, learning and memory. Hippocampal neurons from Cpne6 knockouts lack spine structural plasticity as do wild-type neurons that express a Copine-6 calcium mutant. The function of Copine-6 is based on its binding, activating and recruiting the Rho GTPase Rac1 to cell membranes. Consistent with this function, the LTP deficit of Cpne6 knockout mice is rescued by the actin stabilizer jasplakinolide. These data show that Copine-6 links activity-triggered calcium signals to spine structural plasticity necessary for learning and memory. PMID:27194588

  10. 21 CFR 184.1187 - Calcium alginate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Calcium alginate. 184.1187 Section 184.1187 Food... Specific Substances Affirmed as GRAS § 184.1187 Calcium alginate. (a) Calcium alginate (CAS Reg. No. 9005.... Calcium alginate is prepared by the neutralization of purified alginic acid with appropriate pH...

  11. 21 CFR 172.410 - Calcium silicate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Calcium silicate. 172.410 Section 172.410 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN... Agents § 172.410 Calcium silicate. Calcium silicate, including synthetic calcium silicate, may be...

  12. 21 CFR 172.410 - Calcium silicate.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Calcium silicate. 172.410 Section 172.410 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN... Agents § 172.410 Calcium silicate. Calcium silicate, including synthetic calcium silicate, may be...

  13. 21 CFR 172.410 - Calcium silicate.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Calcium silicate. 172.410 Section 172.410 Food and... PERMITTED FOR DIRECT ADDITION TO FOOD FOR HUMAN CONSUMPTION Anticaking Agents § 172.410 Calcium silicate. Calcium silicate, including synthetic calcium silicate, may be safely used in food in accordance with...

  14. 21 CFR 172.410 - Calcium silicate.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Calcium silicate. 172.410 Section 172.410 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN... Agents § 172.410 Calcium silicate. Calcium silicate, including synthetic calcium silicate, may be...

  15. 21 CFR 172.410 - Calcium silicate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Calcium silicate. 172.410 Section 172.410 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN... Agents § 172.410 Calcium silicate. Calcium silicate, including synthetic calcium silicate, may be...

  16. 21 CFR 184.1201 - Calcium glycerophosphate.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Calcium glycerophosphate. 184.1201 Section 184... as GRAS § 184.1201 Calcium glycerophosphate. (a) Calcium glycerophosphate (C3H7CaO6P, CAS Reg. No... mixture of calcium β-, and D-, and L-α-glycerophosphate. (b) The ingredient meets the specifications...

  17. Children's Bone Health and Calcium

    MedlinePlus

    ... Research Information Clinical Trials Resources and Publications Children's Bone Health and Calcium: Condition Information Skip sharing on ... media links Share this: Page Content What is bone health and how do you build strong bones? ...

  18. Calcium and Arrhythmogenesis

    PubMed Central

    Ter Keurs, Henk E. D. J.; Boyden, Penelope A.

    2010-01-01

    Triggered activity in cardiac muscle and intracellular Ca2+ have been linked in the past. However, today not only are there a number of cellular proteins that show clear Ca2+ dependence but also there are a number of arrhythmias whose mechanism appears to be linked to Ca2+-dependent processes. Thus we present a systematic review of the mechanisms of Ca2+ transport (forward excitation-contraction coupling) in the ventricular cell as well as what is known for other cardiac cell types. Second, we review the molecular nature of the proteins that are involved in this process as well as the functional consequences of both normal and abnormal Ca2+ cycling (e.g., Ca2+ waves). Finally, we review what we understand to be the role of Ca2+ cycling in various forms of arrhythmias, that is, those associated with inherited mutations and those that are acquired and resulting from reentrant excitation and/or abnormal impulse generation (e.g., triggered activity). Further solving the nature of these intricate and dynamic interactions promises to be an important area of research for a better recognition and understanding of the nature of Ca2+ and arrhythmias. Our solutions will provide a more complete understanding of the molecular basis for the targeted control of cellular calcium in the treatment and prevention of such. PMID:17429038

  19. Calcium transport in turtle bladder

    SciTech Connect

    Sabatini, S.; Kurtzman, N.A. )

    1987-12-01

    Unidirectional {sup 45}Ca fluxes were measured in the turtle bladder under open-circuit and short-circuit conditions. In the open-circuited state net calcium flux (J{sup net}{sub Ca}) was secretory (serosa to mucosa). Ouabain reversed J{sup net}{sub Ca} to an absorptive flux. Amiloride reduced both fluxes such that J{sup net}{sub Ca} was not significantly different from zero. Removal of mucosal sodium caused net calcium absorption; removal of serosal sodium caused calcium secretion. When bladders were short circuited, J{sup net}{sub Ca} decreased to approximately one-third of control value but remained secretory. When ouabain was added under short-circuit conditions, J{sup net}{sub Ca} was similar in magnitude and direction to ouabain under open-circuited conditions (i.e., absorptive). Tissue {sup 45}Ca content was {approx equal}30-fold lower when the isotope was placed in the mucosal bath, suggesting that the apical membrane is the resistance barrier to calcium transport. The results obtained in this study are best explained by postulating a Ca{sup 2+}-ATPase on the serosa of the turtle bladder epithelium and a sodium-calcium antiporter on the mucosa. In this model, the energy for calcium movement would be supplied, in large part, by the Na{sup +}-K{sup +}-ATPase. By increasing cell sodium, ouabain would decrease the activity of the mucosal sodium-calcium exchanger (or reverse it), uncovering active calcium transport across the serosa.

  20. Medical therapy, calcium oxalate urolithiasis

    NASA Technical Reports Server (NTRS)

    Ruml, L. A.; Pearle, M. S.; Pak, C. Y.

    1997-01-01

    The development of diagnostic protocols that identify specific risk factors for calcium oxalate nephrolithiasis has led to the formulation of directed medical regimens that are aimed at correcting the underlying metabolic disturbances. Initiation of these treatment programs has reduced markedly the rate of stone formation in the majority of patients who form stones. This article discusses the rationale that underlies the choice of medical therapy for the various pathophysiologic causes of calcium oxalate nephrolithiasis and the appropriate use of available medications.

  1. Gravity, Calcium, and Bone: Update, 1989

    NASA Technical Reports Server (NTRS)

    Arnaud, Sara B.; Morey-Holton, Emily

    1991-01-01

    Some of the results of recent short-term flights and ground-based experiments that have contributed new insights into skeletal adaptation, calcium metabolism, and growth processes in 0 g, are highlighted. After 6 months in space, bone demineralization, invariably involving the os calcis, was found not to extend to the lumbar spine in 4 exercising cosmonauts. A flight experiment in the Space Shuttle crew has documented the early events in the calcium endocrine system during spaceflight. On the ground, brief and long-term bed rest studies of healthy volunteers in the head-down tile (HDT) model of weightlessness were completed. The skeleton of the adult male responds more rapidly to unloading than previously recognized. Regional changes in bone density can be quantified in only 30 days, are highly individual, and follow the direction of gravitational forces in the HDT model during inactivity. Bone biopsy results in healthy volunteers after bed rest differ from results in paraplegics from the same sampling site. Flight experiments in growing rats reveal changes in the composition of bone mineral and matrix in the femur postflight that were found to be highly regional and suggestive of an effect of gravity on mineral distribution. These observations may be relevant to the results from an earlier Cosmos flight where artificial gravity in space was found to maintain bone strength, but not to correct the radial growth deficit.

  2. Streaming energetic electrons in reconnection events

    NASA Astrophysics Data System (ADS)

    Bieber, John W.

    Energetic electrons can be used to probe the large-scale topology of magnetic fields in Earth's magnetotail. In the plasma sheet region near the tail's midplane, these particles normally exhibit the trapped or isotropic angular distributions characteristic of closed magnetic field lines, but brief intervals of intense tailward streaming, indicative of open field lines, are occasionally observed. Such streaming events occur preferentially near the time of substorm onset as the observing spacecraft exits the thinning plasma sheet, and they are usually preceded by a 5-10 minute interval of fast tailward plasma flow and southward magnetic field. These correlated phenomena have been interpreted as evidence for magnetic reconnection at a transient magnetic X-line located ˜15 RE tailward of Earth. Recent studies of energetic electron streaming events report novel reconnection-related phenomena, including heating of plasma electrons, bump-in-tail electron velocity distributions, and possible rotational and tangential magnetic discontinuities.

  3. Streaming energetic electrons in reconnection events

    NASA Astrophysics Data System (ADS)

    Bieber, J. W.

    Energetic electrons can be used to probe the large-scale topology of magnetic fields in earth's magnetotail. In the plasma sheet region near the tail's midplane, these particles normally exhibit the trapped or isotropic angular distributions characteristic of closed magnetic field lines, but brief intervals of intense tailward streaming, indicative of open field lines, are occasionally observed. Such streaming events occur preferentially near the time of substorm onset as the observing spacecraft exits the thinning plasma sheet, and they are usually preceded by a 5-10 minute interval of fast tailward plasma flow and southward magnetic field. These correlated phenomena have been interpreted as evidence for magnetic reconnection at a transient magnetic X-line located at 15 earth radii tailward of earth. Recent studies of energetic electron streaming events report novel reconnection-related phenomena, including heating of plasma electrons, bump-in-tail electron velocity distributions, and possible rotational and tangential magnetic discontinuities.

  4. Impact of calcium-activated potassium channels on NMDA spikes in cortical layer 5 pyramidal neurons

    PubMed Central

    Bock, Tobias

    2016-01-01

    Active electrical events play an important role in shaping signal processing in dendrites. As these events are usually associated with an increase in intracellular calcium, they are likely to be under the control of calcium-activated potassium channels. Here, we investigate the impact of calcium-activated potassium channels on N-methyl-d-aspartate (NMDA) receptor-dependent spikes, or NMDA spikes, evoked by glutamate iontophoresis onto basal dendrites of cortical layer 5 pyramidal neurons. We found that small-conductance calcium-activated potassium channels (SK channels) act to reduce NMDA spike amplitude but at the same time, also decrease the iontophoretic current required for their generation. This SK-mediated decrease in NMDA spike threshold was dependent on R-type voltage-gated calcium channels and indicates a counterintuitive, excitatory effect of SK channels on NMDA spike generation, whereas the capacity of SK channels to suppress NMDA spike amplitude is in line with the expected inhibitory action of potassium channels on dendritic excitability. Large-conductance calcium-activated potassium channels had no significant impact on NMDA spikes, indicating that these channels are either absent from basal dendrites or not activated by NMDA spikes. These experiments reveal complex and opposing interactions among NMDA receptors, SK channels, and voltage-gated calcium channels in basal dendrites of cortical layer 5 pyramidal neurons during NMDA spike generation, which are likely to play an important role in regulating the way these neurons integrate the thousands of synaptic inputs they receive. PMID:26936985

  5. Decline in NAD(P)H autofluorescence precedes apoptotic cell death from chemotherapy

    NASA Astrophysics Data System (ADS)

    Toms, Steven A.; Muhammad, Osman; Jackson, Heather; Lin, Wei-Chiang

    2005-11-01

    OBJECTIVE: Optical spectroscopic tools exist that allow open surgical and minimally invasive assays of intrinsic tissue optics. Optical detection of cellular and tissue viability may offer a minimally invasive way to assess tumor responsiveness to chemotherapies. We report on an optical spectroscopic change that precedes apoptotic cell death and appears related to NAD(P)H autofluorescence. METHODS: The cell lines SW 480 and U87-MG were grown in culture and treated with cisplatin 100 μg/ml and tamoxifen 10 μM, respectively. Fluorescence spectroscopy at 355 nm excitation and 460 nm emission were collected. MTS assays were used to determine cell viability. Cell lysates were analyzed for NAD(P)H concentrations by mass spectroscopy. RESULTS: Autoflourescence at 355 nm excitation and 460 nm emission declines markedly despite normalization for cell number and total protein concentration after treatment with tamoxifen or cisplatin. The autofluorescence drop precedes the loss of cell viability as measured by MTS assay. For example, the relative viability of the U87-MG cell treated with tamoxifen at hours 0, 8, 12 and 24 of treatment was 100 +/- 6, 85 +/- 6, 53 +/- 9 and 0 +/- 3. The relative fluorescence at the same time points were 100 +/- 2, 57 +/- 6, 47 +/- 3, and 0 +/- 1. TUNNEL assays confirm that cell death is via apoptosis. The key cellular fluorophore at these wavelengths is NAD(P)H. Mass spectroscopic analysis of cell lysates at these time points reveals a drop in NAD(P)H concentrations that is parallel to the loss of fluorescence signal. CONCLUSIONS: NAD(P)H autofluoresence decline precedes apoptotic cell death. This may allow the design of minimally invasive spectroscopic tools to monitor chemotherapeutic response.

  6. Gestalt perception and the decline of global precedence in older subjects.

    PubMed

    Staudinger, Markus R; Fink, Gereon R; Mackay, Clare E; Lux, Silke

    2011-01-01

    Our visual world is hierarchically organized. Hierarchical processing is frequently investigated using Navon figures (large letters made up of smaller ones). In young adults, many studies reported faster reaction times (RT) to target letters presented at the global level [i.e., global precedence (GP)]. Furthermore, an age-related decline of this GP has been reported. We tested whether deficits in perceptual grouping via Gestalt laws (Gestalt principles of Proximity and Continuity) might contribute to this decline. In a directed attention task with valid and invalid cues, 20 young (mean age 22) and 20 older (mean age 57) male subjects had to indicate whether a target letter appeared at the global or local level of a Navon figure. The number of local letters forming the global figure was modulated in 5 steps. As expected, during valid trials, young adults showed a GP that linearly increased with increasing numbers of local letters (i.e., GP enhancement). This suggests that GP is related to perceptual grouping via Gestalt laws. By contrast, the group of older subjects demonstrated no precedence effect in RT and a non-significant trend toward GP in error rates (ER). No GP enhancement with an increasing number of local elements was observed. Exploratory analysis revealed that individual insensitivity to the modulation of matrix density, as revealed by a lack of global RT acceleration, was restricted to subjects that showed an overall local precedence (LP). Because older subjects tended to more frequently display an insensitivity to matrix modulation and an LP, we conclude that deficient Gestalt detection as indicated by non-enhanced global RT might contribute to the RT-related decline of GP with age.

  7. Enhanced sensory sampling precedes self-initiated locomotion in an electric fish.

    PubMed

    Jun, James J; Longtin, André; Maler, Leonard

    2014-10-15

    Cortical activity precedes self-initiated movements by several seconds in mammals; this observation has led into inquiries on the nature of volition. Preparatory neural activity is known to be associated with decision making and movement planning. Self-initiated locomotion has been linked to increased active sensory sampling; however, the precise temporal relationship between sensory acquisition and voluntary movement initiation has not been established. Based on long-term monitoring of sensory sampling activity that is readily observable in freely behaving pulse-type electric fish, we show that heightened sensory acquisition precedes spontaneous initiation of swimming. Gymnotus sp. revealed a bimodal distribution of electric organ discharge rate (EODR) demonstrating down- and up-states of sensory sampling and neural activity; movements only occurred during up-states and up-states were initiated before movement onset. EODR during voluntary swimming initiation exhibited greater trial-to-trial variability than the sound-evoked increases in EODR. The sampling variability declined after voluntary movement onset as previously observed for the neural variability associated with decision making in primates. Spontaneous movements occurred randomly without a characteristic timescale, and no significant temporal correlation was found between successive movement intervals. Using statistical analyses of spontaneous exploratory behaviours and associated preparatory sensory sampling increase, we conclude that electric fish exhibit key attributes of volitional movements, and that voluntary behaviours in vertebrates may generally be preceded by increased sensory sampling. Our results suggest that comparative studies of the neural basis of volition may therefore be possible in pulse-type electric fish, given the substantial homologies between the telencephali of teleost fish and mammals.

  8. Third chromosome candidate genes for conspecific sperm precedence between D. simulans and D. mauritiana

    PubMed Central

    2010-01-01

    Background Male - female incompatibilities can be critical in keeping species as separate and discrete units. Premating incompatibilities and postzygotic hybrid sterility/inviability have been widely studied as isolating barriers between species. In recent years, a number of studies have brought attention to postmating prezygotic barriers arising from male - male competition and male - female interactions. Yet little is known about the genetic basis of postmating prezygotic isolation barriers between species. Results Using D. simulans lines with mapped introgressions of D. mauritiana into their third chromosome, we find at least two D. mauritiana introgressions causing male breakdown in competitive paternity success. Eighty one genes within the mapped introgressed regions were identified as broad-sense candidates on the basis of male reproductive tract expression and male-related function. The list of candidates was narrowed down to five genes based on differences in male reproductive tract expression between D. simulans and D. mauritiana. Another ten genes were confirmed as candidates using evidence of adaptive gene coding sequence diversification in the D. simulans and/or D. mauritiana lineage. Our results show a complex genetic basis for conspecific sperm precedence, with evidence of gene interactions between at least two third chromosome loci. Pleiotropy is also evident from correlation between conspecific sperm precedence and female induced fecundity and the identification of candidate genes that might exert an effect through genetic conflict and immunity. Conclusions We identified at least two loci responsible for conspecific sperm precedence. A third of candidate genes within these two loci are located in the 89B cytogenetic position, highlighting a possible major role for this chromosome position during the evolution of species specific adaptations to postmating prezygotic reproductive challenges. PMID:20388218

  9. Behaviour of coconut mites preceding take-off to passive aerial dispersal.

    PubMed

    Melo, J W S; Lima, D B; Sabelis, M W; Pallini, A; Gondim, M G C

    2014-12-01

    For more than three decades the coconut mite Aceria guerreronis Keifer is one of the most important pests of coconut palms and has recently spread to many coconut production areas worldwide. Colonization of coconut palms is thought to arise from mites dispersing aerially after take-off from other plants within the same plantation or other plantations. The underlying dispersal behaviour of the mite at take-off, in the airborne state and after landing is largely unknown and this is essential to understand how they spread from tree to tree. In this article we studied whether take-off to aerial dispersal of coconut mites is preceded by characteristic behaviour, whether there is a correlation between the body position preceding aerial dispersal and the direction of the wind, and whether the substrate (outer surface of coconut bracts or epidermis) and the wind speed matter to the decision to take-off. We found that take-off can sometimes be preceded by a raised body stance, but more frequently take-off occurs while the mite is walking or resting on its substrate. Coconut mites that become airborne assumed a body stance that had no relation to the wind direction. Take-off was suppressed on a substrate providing food to coconut mites, but occurred significantly more frequently on the outer surface of coconut bracts than on the surface of the fruit. For both substrates, take-off frequency increased with wind speed. We conclude that coconut mites have at least some degree of control over take-off for aerial dispersal and that there is as yet no reason to infer that a raised body stance is necessary to become airborne.

  10. "A pattern, precedent, and lively warrant": emulation, rhetoric, and cruel propriety in "Titus Andronicus.".

    PubMed

    Dickson, Vernon Guy

    2009-01-01

    Shakespeare's "Titus Andronicus" critically engages and enacts teachings and patterns of emulation, including those of Quintilian, Roger Ascham, and other contemporary humanists and playwrights, pressing emulation's uses to extremes that suggest that imitative self-fashioning potentially results in monstrous or fragmented characters, decisions, and texts. The professed aim of the grammer-school education, the ability to judge well, is conflicted by "Titus's" exposure of judgment as itself a contested concept, locked within a circularity of intertextual precedents. "Titus's" excessive, even parodic, repetition of emulative strategies acts as a rebuttal of seemingly straightforward humanist models of character, judgment, self, and decorum.

  11. [Listening to women during the interview preceding abortion in unwanted pregnancies (author's transl)].

    PubMed

    Hall, F

    1980-12-01

    According to French law a legally induced abortion must be preceded by a talk between the woman and her doctor, or social worker, or psychologist. The purpose of this talk has been the subject of countless publications; it has never been proven, however, that it is really a useful procedure for the patient, or, on the contrary, a negative procedure a woman must go through to have an abortion. Results of such an encounter are strictly dependent on the personality of the patient, and on the communicative abilities and human sympathy of the other partner in the dialogue.

  12. Onset of bonding plasmon hybridization preceded by gap modes in dielectric splitting of metal disks.

    PubMed

    Frederiksen, Maj; Bochenkov, Vladimir E; Ogaki, Ryosuke; Sutherland, Duncan S

    2013-01-01

    Dielectric splitting of nanoscale disks was studied experimentally and via finite-difference time-domain (FDTD) simulations through systematic introduction of multiple ultrathin dielectric layers. Tunable, hybridized dark bonding modes were seen with first-order gap modes preceding the appearance of bonding dipole-dipole disk modes. The observed bright dipolar mode did not show the energy shift expected from plasmon hybridization but activated dark higher order gap modes. Introducing lateral asymmetry was shown to remodel the field distribution resulting in 3D asymmetry that reoriented the dipole orientation away from the dipole of the elementary disk modes.

  13. A Decrease in Temperature and Humidity Precedes Human Rhinovirus Infections in a Cold Climate

    PubMed Central

    Ikäheimo, Tiina M.; Jaakkola, Kari; Jokelainen, Jari; Saukkoriipi, Annika; Roivainen, Merja; Juvonen, Raija; Vainio, Olli; Jaakkola, Jouni J.K.

    2016-01-01

    Both temperature and humidity may independently or jointly contribute to the risk of human rhinovirus (HRV) infections, either through altered survival and spread of viruses in the environment or due to changes in host susceptibility. This study examined the relationship between short-term variations in temperature and humidity and the risk of HRV infections in a subarctic climate. We conducted a case-crossover study among conscripts (n = 892) seeking medical attention due to respiratory symptoms during their military training and identified 147 HRV cases by real-time PCR. An average temperature, a decline in daily ambient temperature and absolute humidity (AH) during the three preceding days of the onset (hazard period) and two reference periods (a week prior and after the onset) were obtained. The average daily temperature preceding HRV infections was −9.9 ± 4.9 °C and the average AH was 2.2 ± 0.9 g/m3. An average (odds ratios (OR) 1.07 (95% confidence interval (CI) 1.00–1.15)) and maximal (OR 1.08 (1.01–1.17)) change in temperature increased the risk of HRV infections by 8% per 1 °C decrease. An average (OR 1.20 (CI 1.03–1.40)) and maximal decrease (OR 1.13 (CI 0.96–1.34)) in AH increased the risk of HRV infection by 13% and 20% per 0.5 g/m3 decrease. A higher average temperature during the three preceding days was positively associated with HRV infections (OR 1.07 (CI 1.00–1.15)). A decrease rather than low temperature and humidity per se during the preceding few days increases the risk of HRV infections in a cold climate. The information is applicable to populations residing in cold climates for appropriate personal protection and prevention of adverse health effects. PMID:27598190

  14. Calcium metabolism and cardiovascular function after spaceflight

    NASA Technical Reports Server (NTRS)

    Hatton, Daniel C.; Yue, Qi; Dierickx, Jacqueline; Roullet, Chantal; Otsuka, Keiichi; Watanabe, Mitsuaki; Coste, Sarah; Roullet, Jean Baptiste; Phanouvang, Thongchan; Orwoll, Eric; Orwoll, Shiela; McCarron, David A.

    2002-01-01

    To determine the influence of dietary calcium on spaceflight-induced alterations in calcium metabolism and blood pressure (BP), 9-wk-old spontaneously hypertensive rats, fed either high- (2%) or low-calcium (0.02%) diets, were flown on an 18-day shuttle flight. On landing, flight animals had increased ionized calcium (P < 0.001), elevated parathyroid hormone levels (P < 0.001), reduced calcitonin levels (P < 0.05), unchanged 1,25(OH)(2)D(3) levels, and elevated skull (P < 0.01) and reduced femur bone mineral density. Basal and thrombin-stimulated platelet free calcium (intracellular calcium concentration) were also reduced (P < 0.05). There was a tendency for indirect systolic BP to be reduced in conscious flight animals (P = 0.057). However, mean arterial pressure was elevated (P < 0.001) after anesthesia. Dietary calcium altered all aspects of calcium metabolism (P < 0.001), as well as BP (P < 0.001), but the only interaction with flight was a relatively greater increase in ionized calcium in flight animals fed low- compared with high-calcium diets (P < 0.05). The results indicate that 1) flight-induced disruptions of calcium metabolism are relatively impervious to dietary calcium in the short term, 2) increased ionized calcium did not normalize low-calcium-induced elevations of BP, and 3) parathyroid hormone was paradoxically increased in the high-calcium-fed flight animals after landing.

  15. Assessing Special Events.

    ERIC Educational Resources Information Center

    Neff, Bonita Dostal

    Special events defined as being "newsworthy events" are becoming a way of American life. They are also a means for making a lot of money. Examples of special events that are cited most frequently are often the most minor of events; e.g., the open house, the new business opening day gala, or a celebration of some event in an organization.…

  16. Calcium signaling and cytotoxicity.

    PubMed Central

    Kass, G E; Orrenius, S

    1999-01-01

    The divalent calcium cation Ca(2+) is used as a major signaling molecule during cell signal transduction to regulate energy output, cellular metabolism, and phenotype. The basis to the signaling role of Ca(2+) is an intricate network of cellular channels and transporters that allow a low resting concentration of Ca(2+) in the cytosol of the cell ([Ca(2+)]i) but that are also coupled to major dynamic and rapidly exchanging stores. This enables extracellular signals from hormones and growth factors to be transduced as [Ca(2+)]i spikes that are amplitude and frequency encoded. There is considerable evidence that a number of toxic environmental chemicals target these Ca(2+) signaling processes, alter them, and induce cell death by apoptosis. Two major pathways for apoptosis will be considered. The first one involves Ca(2+)-mediated expression of ligands that bind to and activate death receptors such as CD95 (Fas, APO-1). In the second pathway, Ca(2+) has a direct toxic effect and its primary targets include the mitochondria and the endoplasmic reticulum (ER). Mitochondria may respond to an apoptotic Ca(2+) signal by the selective release of cytochrome c or through enhanced production of reactive oxygen species and opening of an inner mitochondrial membrane pore. Toxic agents such as the environmental pollutant tributyltin or the natural plant product thapsigargin, which deplete the ER Ca(2+) stores, will induce as a direct result of this effect the opening of plasma membrane Ca(2+) channels and an ER stress response. In contrast, under some conditions, Ca(2+) signals may be cytoprotective and antagonize the apoptotic machinery. Images Figure 1 Figure 2 Figure 3 PMID:10229704

  17. Event Segmentation Ability Uniquely Predicts Event Memory

    PubMed Central

    Sargent, Jesse Q.; Zacks, Jeffrey M.; Hambrick, David Z.; Zacks, Rose T.; Kurby, Christopher A.; Bailey, Heather R.; Eisenberg, Michelle L.; Beck, Taylor M.

    2013-01-01

    Memory for everyday events plays a central role in tasks of daily living, autobiographical memory, and planning. Event memory depends in part on segmenting ongoing activity into meaningful units. This study examined the relationship between event segmentation and memory in a lifespan sample to answer the following question: Is the ability to segment activity into meaningful events a unique predictor of subsequent memory, or is the relationship between event perception and memory accounted for by general cognitive abilities? Two hundred and eight adults ranging from 20 to 79 years old segmented movies of everyday events and attempted to remember the events afterwards. They also completed psychometric ability tests and tests measuring script knowledge for everyday events. Event segmentation and script knowledge both explained unique variance in event memory above and beyond the psychometric measures, and did so as strongly in older as in younger adults. These results suggest that event segmentation is a basic cognitive mechanism, important for memory across the lifespan. PMID:23942350

  18. Clonal expansion of CD8 T cells in the systemic circulation precedes development of ipilimumab-induced toxicities

    PubMed Central

    Subudhi, Sumit K.; Aparicio, Ana; Gao, Jianjun; Zurita, Amado J.; Araujo, John C.; Logothetis, Christopher J.; Tahir, Salahaldin A.; Korivi, Brinda R.; Slack, Rebecca S.; Vence, Luis; Emerson, Ryan O.; Yusko, Erik; Vignali, Marissa; Robins, Harlan S.; Sun, Jingjing; Allison, James P.; Sharma, Padmanee

    2016-01-01

    Immune checkpoint therapies, such as ipilimumab, induce dramatic antitumor responses in a subset of patients with advanced malignancies, but they may also induce inflammatory responses and toxicities termed immune-related adverse events (irAEs). These irAEs are often low grade and manageable, but severe irAEs may lead to prolonged hospitalizations or fatalities. Early intervention is necessary to minimize morbidities that occur with severe irAEs. However, correlative biomarkers are currently lacking. In a phase II clinical trial that treated 27 patients with metastatic prostate cancer, we aimed to test the safety and efficacy of androgen deprivation therapy plus ipilimumab. In this study, we observed grade 3 toxicities in >40% of treated patients, which led to early closure of the study. Because ipilimumab enhances T-cell responses, we hypothesized that increased clonal T-cell responses in the systemic circulation may contribute to irAEs. Sequencing of the T-cell receptor β-chains in purified T cells revealed clonal expansion of CD8 T cells, which occurred in blood samples collected before the onset of grade 2–3 irAEs. These initial results suggested that expansion of ≥55 CD8 T-cell clones preceded the development of severe irAEs. We further evaluated available blood samples from a second trial and determined that patients who experienced grade 2–3 irAEs also had expansion of ≥55 CD8 T-cell clones in blood samples collected before the onset of irAEs. We propose that CD8 T-cell clonal expansion may be a correlative biomarker to enable close monitoring and early intervention for patients receiving ipilimumab. PMID:27698113

  19. A Type I Interferon Transcriptional Signature Precedes Autoimmunity in Children Genetically at Risk for Type 1 Diabetes

    PubMed Central

    Ferreira, Ricardo C.; Guo, Hui; Coulson, Richard M.R.; Smyth, Deborah J.; Pekalski, Marcin L.; Burren, Oliver S.; Cutler, Antony J.; Doecke, James D.; Flint, Shaun; McKinney, Eoin F.; Lyons, Paul A.; Smith, Kenneth G.C.; Achenbach, Peter; Beyerlein, Andreas; Dunger, David B.; Clayton, David G.; Wicker, Linda S.; Bonifacio, Ezio

    2014-01-01

    Diagnosis of the autoimmune disease type 1 diabetes (T1D) is preceded by the appearance of circulating autoantibodies to pancreatic islets. However, almost nothing is known about events leading to this islet autoimmunity. Previous epidemiological and genetic data have associated viral infections and antiviral type I interferon (IFN) immune response genes with T1D. Here, we first used DNA microarray analysis to identify IFN-β–inducible genes in vitro and then used this set of genes to define an IFN-inducible transcriptional signature in peripheral blood mononuclear cells from a group of active systemic lupus erythematosus patients (n = 25). Using this predefined set of 225 IFN signature genes, we investigated the expression of the signature in cohorts of healthy controls (n = 87), patients with T1D (n = 64), and a large longitudinal birth cohort of children genetically predisposed to T1D (n = 109; 454 microarrayed samples). Expression of the IFN signature was increased in genetically predisposed children before the development of autoantibodies (P = 0.0012) but not in patients with established T1D. Upregulation of IFN-inducible genes was transient, temporally associated with a recent history of upper respiratory tract infections (P = 0.0064), and marked by increased expression of SIGLEC-1 (CD169), a lectin-like receptor expressed on CD14+ monocytes. DNA variation in IFN-inducible genes altered T1D risk (P = 0.007), as exemplified by IFIH1, one of the genes in our IFN signature for which increased expression is a known risk factor for disease. These findings identify transient increased expression of type I IFN genes in preclinical diabetes as a risk factor for autoimmunity in children with a genetic predisposition to T1D. PMID:24561305

  20. The effect of preceding wintertime Arctic polar vortex on springtime NDVI patterns in boreal Eurasia, 1982-2015

    NASA Astrophysics Data System (ADS)

    Li, Jing; Fan, Ke; Xu, Jianjun; Powell, Alfred M.; Kogan, Felix

    2016-08-01

    The polar vortex is implicated in certain cold events in boreal Eurasia and has a further influence on land surface properties (e.g., vegetation and snow) during spring. The Normalized Difference Vegetation Index (NDVI) can be used as a proxy of land surface responses to climate changes to a certain degree. In this study, we demonstrate the significant correlation between preceding wintertime Arctic polar vortex intensity (WAPVI) and springtime NDVI (SNDVI) over a 34-year period (1982-2015) in boreal Eurasia (50°-75°N, 0°-150°E). Results show that a positive phase of WAPVI tends to increase the SNDVI in Europe and Lake Baikal, but causes a significant decrease in Siberia; the physical mechanisms involved in this relationship are then investigated. A positive phase of WAPVI leads to anomalies in surface air temperature and rainfall over Eurasia, which then induces a significant decrease in snow cover and snow depth in Europe and Lake Baikal and an increase of snow depth in Siberia. The colder ground temperature in Siberia during spring is considered responsible for the stronger snow depth and weaker vegetation growth in this region. The weaker and thinner snow cover in Europe and Baikal produces a decrease in albedo and an increase in heat. Thin snow melts fast in the following spring and land releases more heat to the atmosphere; consequently, warm and moist land surface facilitates vegetation growth in Europe and the Baikal regions during positive WAPVI years. In addition, WAPVI can induce sea surface temperature (SST) anomalies in the North Atlantic, which displays a tripole pattern similar to that of the empirical mode pattern in winter. Furthermore, the SST anomalous pattern persisting from winter to spring can trigger a stationary wave-train propagating from west to east in boreal Eurasia, with "negative-positive-negative-positive" geopotential height anomalies, which further exerts an impact on vegetation growth through modulation of the heat balance.

  1. Clonal expansion of CD8 T cells in the systemic circulation precedes development of ipilimumab-induced toxicities.

    PubMed

    Subudhi, Sumit K; Aparicio, Ana; Gao, Jianjun; Zurita, Amado J; Araujo, John C; Logothetis, Christopher J; Tahir, Salahaldin A; Korivi, Brinda R; Slack, Rebecca S; Vence, Luis; Emerson, Ryan O; Yusko, Erik; Vignali, Marissa; Robins, Harlan S; Sun, Jingjing; Allison, James P; Sharma, Padmanee

    2016-10-18

    Immune checkpoint therapies, such as ipilimumab, induce dramatic antitumor responses in a subset of patients with advanced malignancies, but they may also induce inflammatory responses and toxicities termed immune-related adverse events (irAEs). These irAEs are often low grade and manageable, but severe irAEs may lead to prolonged hospitalizations or fatalities. Early intervention is necessary to minimize morbidities that occur with severe irAEs. However, correlative biomarkers are currently lacking. In a phase II clinical trial that treated 27 patients with metastatic prostate cancer, we aimed to test the safety and efficacy of androgen deprivation therapy plus ipilimumab. In this study, we observed grade 3 toxicities in >40% of treated patients, which led to early closure of the study. Because ipilimumab enhances T-cell responses, we hypothesized that increased clonal T-cell responses in the systemic circulation may contribute to irAEs. Sequencing of the T-cell receptor β-chains in purified T cells revealed clonal expansion of CD8 T cells, which occurred in blood samples collected before the onset of grade 2-3 irAEs. These initial results suggested that expansion of ≥55 CD8 T-cell clones preceded the development of severe irAEs. We further evaluated available blood samples from a second trial and determined that patients who experienced grade 2-3 irAEs also had expansion of ≥55 CD8 T-cell clones in blood samples collected before the onset of irAEs. We propose that CD8 T-cell clonal expansion may be a correlative biomarker to enable close monitoring and early intervention for patients receiving ipilimumab.

  2. DNA breakage and induction of DNA damage response proteins precede the appearance of visible mutant huntingtin aggregates.

    PubMed

    Illuzzi, Jennifer; Yerkes, Sarah; Parekh-Olmedo, Hetal; Kmiec, Eric B

    2009-02-15

    Huntington's disease (HD) is a neurodegenerative disorder that follows an autosomal-dominant inheritance pattern. The pathogenesis of the disease depends on the degree of expansion of triplet (CAG) repeats located in the first exon on the gene. An expanded polyglutamine tract within the protein huntingtin (Htt) enables a gain-of-function phenotype that is often exhibited by a dysfunctional oligomerization process and the formation of protein aggregates. How this process leads to neurodegeneration remains undefined. We report that expression of a Htt-fragment containing an expanded glutamine tract induces DNA damage and activates the DNA damage response pathway. Both single-strand and double-strand breaks are observed as the mutant protein accumulates in the cell; these breaks precede the appearance of detectable protein aggregates containing mutant Htt. We also observe activation of H2AX, ATM, and p53 in cells expressing mutant Htt, a predictable response in cells containing chromosomal breakage. Expression of wild-type Htt does not affect the integrity of DNA, nor does it activate the same pathway. Furthermore, DNA damage and activated H2AX are present in HD transgenic mice before the formation of mutant Htt aggregates and HD pathogenesis. Taken together, our data suggest that the expression of mutant Htt causes an accumulation of DNA breaks that activates the DNA damage response pathway, a process that can disable cell function. Because these events can lead to apoptosis, it is possible that the DNA damage response pathway activated by single- and double-strand breaks that we found contributes to neurodegeneration.

  3. Calcium signalling and calcium channels: Evolution and general principles

    PubMed Central

    Verkhratsky, Alexei; Parpura, Vladimir

    2014-01-01

    Calcium as a divalent ion was selected early in evolution as a signaling molecule to be used by both prokaryotes and eukaryotes. Its low cytosolic concentration likely reflects the initial concentration of this ion in the primordial soup/ocean as unicellular organisms were formed. As the concentration of calcium in the ocean subsequently increased, so did the diversity of homeostatic molecules. This includes the plasma membrane channels that allowed the calcium entry, as well as extrusion mechanisms, i.e., exchangers and pumps. Further diversification occurred with the evolution of intracellular organelles, in particular the endoplasmic reticulum and mitochondria, which also contain channels, exchanger(s) and pumps to handle the homeostasis of calcium ions. Calcium signalling system, based around coordinated interactions of the above molecular entities, can be activated by the opening of voltage-gated channels, by neurotransmitters, by second messengers and/or mechanical stimulation, and as such is all-pervading pathway in physiology and pathophysiology of organisms. PMID:24291103

  4. Dopaminergic regulation of dendritic calcium: fast multisite calcium imaging.

    PubMed

    Zhou, Wen-Liang; Oikonomou, Katerina D; Short, Shaina M; Antic, Srdjan D

    2013-01-01

    Optimal dopamine tone is required for the normal cortical function; however it is still unclear how cortical-dopamine-release affects information processing in individual cortical neurons. Thousands of glutamatergic inputs impinge onto elaborate dendritic trees of neocortical pyramidal neurons. In the process of ensuing synaptic integration (information processing), a variety of calcium transients are generated in remote dendritic compartments. In order to understand the cellular mechanisms of dopaminergic modulation it is important to know whether and how dopaminergic signals affect dendritic calcium transients. In this chapter, we describe a relatively inexpensive method for monitoring dendritic calcium fluctuations at multiple loci across the pyramidal dendritic tree, at the same moment of time (simultaneously). The experiments have been designed to measure the amplitude, time course and spatial extent of action potential-associated dendritic calcium transients before and after application of dopaminergic drugs. In the examples provided here the dendritic calcium transients were evoked by triggering the somatic action potentials (backpropagation-evoked), and puffs of exogenous dopamine were applied locally onto selected dendritic branches.

  5. Diffusive spatio-temporal noise in a first-passage time model for intracellular calcium release

    NASA Astrophysics Data System (ADS)

    Flegg, Mark B.; Rüdiger, Sten; Erban, Radek

    2013-04-01

    The intracellular release of calcium from the endoplasmic reticulum is controlled by ion channels. The resulting calcium signals exhibit a rich spatio-temporal signature, which originates at least partly from microscopic fluctuations. While stochasticity in the gating transition of ion channels has been incorporated into many models, the distribution of calcium is usually described by deterministic reaction-diffusion equations. Here we test the validity of the latter modeling approach by using two different models to calculate the frequency of localized calcium signals (calcium puffs) from clustered IP3 receptor channels. The complexity of the full calcium system is here limited to the basic opening mechanism of the ion channels and, in the mathematical reduction simplifies to the calculation of a first passage time. Two models are then studied: (i) a hybrid model, where channel gating is treated stochastically, while calcium concentration is deterministic and (ii) a fully stochastic model with noisy channel gating and Brownian calcium ion motion. The second model utilises the recently developed two-regime method [M. B. Flegg, S. J. Chapman, and R. Erban, "The two-regime method for optimizing stochastic reaction-diffusion simulations," J. R. Soc., Interface 9, 859-868 (2012)], 10.1098/rsif.2011.0574 in order to simulate a large domain with precision required only near the Ca2+ absorbing channels. The expected time for a first channel opening that results in a calcium puff event is calculated. It is found that for a large diffusion constant, predictions of the interpuff time are significantly overestimated using the model (i) with a deterministic non-spatial calcium variable. It is thus demonstrated that the presence of diffusive noise in local concentrations of intracellular Ca2+ ions can substantially influence the occurrence of calcium signals. The presented approach and results may also be relevant for other cell-physiological first-passage time problems with

  6. Plasma membrane calcium channels in cancer: Alterations and consequences for cell proliferation and migration.

    PubMed

    Déliot, Nadine; Constantin, Bruno

    2015-10-01

    The study of calcium channels in molecular mechanisms of cancer transformation is still a novel area of research. Several studies, mostly conducted on cancer cell lines, however support the idea that a diversity of plasma membrane channels participates in the remodeling of Ca2+ homeostasis, which regulates various cancer hallmarks such as uncontrolled multiplication and increase in migration and invasion abilities. However few is still understood concerning the intracellular signaling cascades mobilized by calcium influx participating to cancer cell behavior. This review intends to gather some of these pathways dependent on plasma membrane calcium channels and described in prostate, breast and lung cancer cell lines. In these cancer cell types, the calcium channels involved in calcium signaling pathways promoting cancer behaviors are mostly non-voltage activated calcium channels and belong to the TRP superfamily (TRPC, TPRPV and TRPM families) and the Orai family. TRP and Orai channels are part of many signaling cascades involving the activation of transmembrane receptors by extracellular ligand from the tumor environment. TRPV can sense changes in the physical and chemical environment of cancer cells and TRPM7 are stretch activated and sensitive to cholesterol. Changes in activation and or expression of plasma-membrane calcium channels affect calcium-dependent signaling processes relevant to tumorigenesis. The studies cited in this review suggest that an increase in plasma membrane calcium channel expression and/or activity sustain an elevated calcium entry (constitutive or under the control of extracellular signals) promoting higher cell proliferation and migration in most cases. A variety of non-voltage-operated calcium channels display change expression and/or activity in a same cancer type and cooperate to the same process relevant to cancer cell behavior, or can be involved in a different sequence of events during the tumorigenesis. This article is part of a

  7. Induction of epithelial-mesenchymal transition (EMT) in breast cancer cells is calcium signal dependent.

    PubMed

    Davis, F M; Azimi, I; Faville, R A; Peters, A A; Jalink, K; Putney, J W; Goodhill, G J; Thompson, E W; Roberts-Thomson, S J; Monteith, G R

    2014-05-01

    Signals from the tumor microenvironment trigger cancer cells to adopt an invasive phenotype through epithelial-mesenchymal transition (EMT). Relatively little is known regarding key signal transduction pathways that serve as cytosolic bridges between cell surface receptors and nuclear transcription factors to induce EMT. A better understanding of these early EMT events may identify potential targets for the control of metastasis. One rapid intracellular signaling pathway that has not yet been explored during EMT induction is calcium. Here we show that stimuli used to induce EMT produce a transient increase in cytosolic calcium levels in human breast cancer cells. Attenuation of the calcium signal by intracellular calcium chelation significantly reduced epidermal growth factor (EGF)- and hypoxia-induced EMT. Intracellular calcium chelation also inhibited EGF-induced activation of signal transducer and activator of transcription 3 (STAT3), while preserving other signal transduction pathways such as Akt and extracellular signal-regulated kinase 1/2 (ERK1/2) phosphorylation. To identify calcium-permeable channels that may regulate EMT induction in breast cancer cells, we performed a targeted siRNA-based screen. We found that transient receptor potential-melastatin-like 7 (TRPM7) channel expression regulated EGF-induced STAT3 phosphorylation and expression of the EMT marker vimentin. Although intracellular calcium chelation almost completely blocked the induction of many EMT markers, including vimentin, Twist and N-cadherin, the effect of TRPM7 silencing was specific for vimentin protein expression and STAT3 phosphorylation. These results indicate that TRPM7 is a partial regulator of EMT in breast cancer cells, and that other calcium-permeable ion channels are also involved in calcium-dependent EMT induction. In summary, this work establishes an important role for the intracellular calcium signal in the induction of EMT in human breast cancer cells. Manipulation of

  8. Increased calcium bioavailability in mice fed genetically engineered plants lacking calcium oxalate

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Bioavailable calcium affects bone formation and calcification. Here we investigate how a single gene mutation altering calcium partitioning in the model forage crop Medicago truncatula affects calcium bioavailability. Previously, the cod5 M. truncatula mutant was identified which contains identical ...

  9. Genetic evidence in the mouse solidifies the calcium hypothesis of myofiber death in muscular dystrophy

    PubMed Central

    Burr, A R; Molkentin, J D

    2015-01-01

    Muscular dystrophy (MD) refers to a clinically and genetically heterogeneous group of degenerative muscle disorders characterized by progressive muscle wasting and often premature death. Although the primary defect underlying most forms of MD typically results from a loss of sarcolemmal integrity, the secondary molecular mechanisms leading to muscle degeneration and myofiber necrosis is debated. One hypothesis suggests that elevated or dysregulated cytosolic calcium is the common transducing event, resulting in myofiber necrosis in MD. Previous measurements of resting calcium levels in myofibers from dystrophic animal models or humans produced equivocal results. However, recent studies in genetically altered mouse models have largely solidified the calcium hypothesis of MD, such that models with artificially elevated calcium in skeletal muscle manifest fulminant dystrophic-like disease, whereas models with enhanced calcium clearance or inhibited calcium influx are resistant to myofiber death and MD. Here, we will review the field and the recent cadre of data from genetically altered mouse models, which we propose have collectively mostly proven the hypothesis that calcium is the primary effector of myofiber necrosis in MD. This new consensus on calcium should guide future selection of drugs to be evaluated in clinical trials as well as gene therapy-based approaches. PMID:26088163

  10. Depolarization-stimulated contractility of gastrointestinal smooth muscle in calcium-free solution: a review.

    PubMed

    Evans, Emily D; Mangel, Allen W

    2011-01-01

    The membrane of most gastrointestinal smooth muscles shows slow waves, slow rhythmic changes in membrane potential. Slow waves serve to bring the membrane potential of smooth muscle cells to a threshold level that elicits a second electrical event known as the spike or action potential. The inward current of the spike, in most gastrointestinal smooth muscle preparations, is carried, at least in part, by calcium. Indeed, considering the narrow diameter of smooth muscle cells, some have hypothesized that the influx of calcium during the spike is sufficient for activation of the contractile machinery. Findings consistent with this include marked reduction in contractility during exposure of muscle segments to blockers of L-type calcium channels or following reductions in external calcium levels. However, it has also been observed that following exposure of muscle segments to external bathing solutions containing no added calcium plus 5 mM EGTA to remove any remaining extracellular calcium, contractions can be triggered following membrane depolarization. It is noteworthy that in isolated smooth muscle cells or in small muscle segments, during incubation in calcium-free solution, depolarization does not induce contractions. The present paper discusses the evidence in support of depolarization-mediated contractions occurring in gastrointestinal smooth muscle segments during incubation in solutions devoid of calcium.

  11. Measuring near plasma membrane and global intracellular calcium dynamics in astrocytes.

    PubMed

    Shigetomi, Eiji; Khakh, Baljit S

    2009-04-26

    The brain contains glial cells. Astrocytes, a type of glial cell, have long been known to provide a passive supportive role to neurons. However, increasing evidence suggests that astrocytes may also actively participate in brain function through functional interactions with neurons. However, many fundamental aspects of astrocyte biology remain controversial, unclear and/or experimentally unexplored. One important issue is the dynamics of intracellular calcium transients in astrocytes. This is relevant because calcium is well established as an important second messenger and because it has been proposed that astrocyte calcium elevations can trigger the release of transmitters from astrocytes. However, there has not been any detailed or satisfying description of near plasma membrane calcium signaling in astrocytes. Total internal reflection fluorescence (TIRF) microscopy is a powerful tool to analyze physiologically relevant signaling events within about 100 nm of the plasma membrane of live cells. Here, we use TIRF microscopy and describe how to monitor near plasma membrane and global intracellular calcium dynamics almost simultaneously. The further refinement and systematic application of this approach has the potential to inform about the precise details of astrocyte calcium signaling. A detailed understanding of astrocyte calcium dynamics may provide a basis to understand if, how, when and why astrocytes and neurons undergo calcium-dependent functional interactions.

  12. Electric pulses: a flexible tool to manipulate cytosolic calcium concentrations and generate spontaneous-like calcium oscillations in mesenchymal stem cells

    PubMed Central

    de Menorval, Marie-Amelie; Andre, Franck M.; Silve, Aude; Dalmay, Claire; Français, Olivier; Le Pioufle, Bruno; Mir, Lluis M.

    2016-01-01

    Human adipose mesenchymal stem cells (haMSCs) are multipotent adult stem cells of great interest in regenerative medicine or oncology. They present spontaneous calcium oscillations related to cell cycle progression or differentiation but the correlation between these events is still unclear. Indeed, it is difficult to mimic haMSCs spontaneous calcium oscillations with chemical means. Pulsed electric fields (PEFs) can permeabilise plasma and/or organelles membranes depending on the applied pulses and therefore generate cytosolic calcium peaks by recruiting calcium from the external medium or from internal stores. We show that it is possible to mimic haMSCs spontaneous calcium oscillations (same amplitude, duration and shape) using 100 μs PEFs or 10 ns PEFs. We propose a model that explains the experimental situations reported. PEFs can therefore be a flexible tool to manipulate cytosolic calcium concentrations. This tool, that can be switched on and off instantaneously, contrary to chemicals agents, can be very useful to investigate the role of calcium oscillations in cell physiology and/or to manipulate cell fate. PMID:27561994

  13. Effects of verbal event structure on online thematic role assignment.

    PubMed

    Malaia, Evie; Wilbur, Ronnie B; Weber-Fox, Christine

    2012-10-01

    Event structure describes the relationships between general semantics (Aktionsart) of the verb and its syntactic properties, separating verbs into two classes: telic verbs, which denote change of state events with an inherent end-point or boundary (catch, rescue), and atelic, which refer to homogenous activities (tease, host). As telic verbs describe events, in which the internal argument (Patient) is affected, we hypothesized that processing of telic verb template would activate syntactic position of the Patient during sentence comprehension. Event-related brain potentials (ERPs) were recorded from 20 English speakers, who read sentences with reduced Object relative clauses, in which the verb was either telic or atelic. ERPs in relative clauses diverged on the definite article preceding the Agent: the atelic condition was characterized by larger amplitude negativity at the N100. Such processing differences are explained by activation of the syntactic position for the Patient by the event structure template of telic verbs.

  14. Type 2 radio bursts, interplanetary shocks and energetic particle events

    NASA Technical Reports Server (NTRS)

    Cane, H. V.; Stone, R. G.

    1982-01-01

    Using the ISEE-3 radio astronomy experiment data 37 interplanetary (IP) type II bursts have been identified in the period September 1978 to December 1981. These events and the associated phenomena are listed. The events are preceded by intense, soft X ray events with long decay times (LDEs) and type II and/or type IV bursts at meter wavelengths. The meter wavelength type II bursts are usually intense and exhibit herringbone structure. The extension of the herringbone structure into the kilometer wavelength range results in the occurrence of a shock accelerated (SA) event. The majority of the interplanetary type II bursts are associated with energetic particle events. These results support other studies which indicate that energetic solar particles detected at 1 A.U. are generated by shock acceleration. From a preliminary analysis of the available data there appears to be a high correlation with white light coronal transients.

  15. Calcium wave of tubuloglomerular feedback.

    PubMed

    Peti-Peterdi, János

    2006-08-01

    ATP release from macula densa (MD) cells into the interstitium of the juxtaglomerular (JG) apparatus (JGA) is an integral component of the tubuloglomerular feedback (TGF) mechanism that controls the glomerular filtration rate. Because the cells of the JGA express a number of calcium-coupled purinergic receptors, these studies tested the hypothesis that TGF activation triggers a calcium wave that spreads from the MD toward distant cells of the JGA and glomerulus. Ratiometric calcium imaging of in vitro microperfused isolated JGA-glomerulus complex dissected from rabbits was performed with fluo-4/fura red and confocal fluorescence microscopy. Activation of TGF by increasing tubular flow rate at the MD rapidly produced a significant elevation in intracellular Ca(2+) concentration ([Ca(2+)](i)) in extraglomerular mesangial cells (by 187.6 +/- 45.1 nM) and JG renin granular cells (by 281.4 +/- 66.6 nM). Subsequently, cell-to-cell propagation of the calcium signal at a rate of 12.6 +/- 1.1 microm/s was observed upstream toward proximal segments of the afferent arteriole and adjacent glomeruli, as well as toward intraglomerular elements including the most distant podocytes (5.9 +/- 0.4 microm/s). The same calcium wave was observed in nonperfusing glomeruli, causing vasoconstriction and contractions of the glomerular tuft. Gap junction uncoupling, an ATP scavenger enzyme cocktail, and pharmacological inhibition of P(2) purinergic receptors, but not adenosine A(1) receptor blockade, abolished the changes in [Ca(2+)](i) and propagation of the calcium wave. These studies provided evidence that both gap junctional communication and extracellular ATP are integral components of the TGF calcium wave.

  16. [Calcium metabolism characteristics in microgravity].

    PubMed

    Grigor'ev, A I; Larina, I M; Morukov, B V

    1999-06-01

    The results of research of calcium exchange parameters at cosmonauts taken part in long space flights (SF) onboard of orbital stations "SALUT" and "MIR" within 1978-1998 were generalized. The analysis of data received during observation of 44 cosmonauts (18 of them have taken part in long SF twice) was done. The observation was carried out before and after SF by duration 30-438 days. The content of a total calcium in blood serum was increased basically by the increase of its ionized fraction after flights of moderate (3-6 months) and large duration (6-14 months) along with the significant increase of PTH and decrease of calcitonin levels. The content of osteocalcin after SF was increased. Three cosmonauts participated in research of calcium kinetics using stable isotopes before, in time and after a 115-day SF. Reduction of intestinal absorption, excretion through a gastrointestinal tract, and increase of calcium excretion with urine were marked in time of SF. In early postflight period a level of intestinal absorption, on the average, was much lower than in SF, and the calcium removal through intestine was increased. Both renal and intestinal excretion of calcium were not normalized in 3.5-4.5 months after end of SF. Increase of resorbtive processes in bone tissues which induced negative bone balance during flight was observed in all test subjects, proceeding from estimations of speed of the basic calcium flows made on the basis of mathematical modeling. The conclusion about decrease in speed of bone tissue remodeling and strengthening of its resorption proves to be true by data of research of biochemical and endocrine markers.

  17. Simultaneous Sodium and Calcium Imaging from Dendrites and Axons

    PubMed Central

    Miyazaki, Kenichi

    2015-01-01

    Abstract Dynamic calcium imaging is a major technique of neuroscientists. It can reveal information about the location of various calcium channels and calcium permeable receptors, the time course, magnitude, and location of intracellular calcium concentration ([Ca2+]i) changes, and indirectly, the occurrence of action potentials. Dynamic sodium imaging, a less exploited technique, can reveal analogous information related to sodium signaling. In some cases, like the examination of AMPA and NMDA receptor signaling, measurements of both [Ca2+]i and [Na+]i changes in the same preparation may provide more information than separate measurements. To this end, we developed a technique to simultaneously measure both signals at high speed and sufficient sensitivity to detect localized physiologic events. This approach has advantages over sequential imaging because the preparation may not respond identically in different trials. We designed custom dichroic and emission filters to allow the separate detection of the fluorescence of sodium and calcium indicators loaded together into a single neuron in a brain slice from the hippocampus of Sprague-Dawley rats. We then used high-intensity light emitting diodes (LEDs) to alternately excite the two indicators at the appropriate wavelengths. These pulses were synchronized with the frames of a CCD camera running at 500 Hz. Software then separated the data streams to provide independent sodium and calcium signals. With this system we could detect [Ca2+]i and [Na+]i changes from single action potentials in axons and synaptically evoked signals in dendrites, both with submicron resolution and a good signal-to-noise ratio (S/N). PMID:26730401

  18. Simultaneous Sodium and Calcium Imaging from Dendrites and Axons.

    PubMed

    Miyazaki, Kenichi; Ross, William N

    2015-01-01

    Dynamic calcium imaging is a major technique of neuroscientists. It can reveal information about the location of various calcium channels and calcium permeable receptors, the time course, magnitude, and location of intracellular calcium concentration ([Ca(2+)]i) changes, and indirectly, the occurrence of action potentials. Dynamic sodium imaging, a less exploited technique, can reveal analogous information related to sodium signaling. In some cases, like the examination of AMPA and NMDA receptor signaling, measurements of both [Ca(2+)]i and [Na(+)]i changes in the same preparation may provide more information than separate measurements. To this end, we developed a technique to simultaneously measure both signals at high speed and sufficient sensitivity to detect localized physiologic events. This approach has advantages over sequential imaging because the preparation may not respond identically in different trials. We designed custom dichroic and emission filters to allow the separate detection of the fluorescence of sodium and calcium indicators loaded together into a single neuron in a brain slice from the hippocampus of Sprague-Dawley rats. We then used high-intensity light emitting diodes (LEDs) to alternately excite the two indicators at the appropriate wavelengths. These pulses were synchronized with the frames of a CCD camera running at 500 Hz. Software then separated the data streams to provide independent sodium and calcium signals. With this system we could detect [Ca(2+)]i and [Na(+)]i changes from single action potentials in axons and synaptically evoked signals in dendrites, both with submicron resolution and a good signal-to-noise ratio (S/N).

  19. Elevated prolactin levels immediately precede decisions to babysit by male meerkat helpers.

    PubMed

    Carlson, Anne A; Russell, Andrew F; Young, Andrew J; Jordan, Neil R; McNeilly, Alan S; Parlow, Al F; Clutton-Brock, Tim

    2006-06-01

    Recent studies suggest that decisions to care for the offspring of others in societies of cooperative vertebrates may have a hormonal basis. The crucial question of whether changes in hormone levels immediately precede or merely follow bouts of offspring care, however, remains largely unanswered. Here, we show that in wild groups of cooperatively breeding meerkats, male helpers that decided to babysit for the day had significantly higher levels of prolactin, coupled with lower levels of cortisol, before initiating a babysitting session compared with similarly aged individuals that decided to forage. In addition, these hormonal differences disappeared over the course of the day, suggesting that hormone levels changed in a fundamentally different way in meerkats that babysat versus those that foraged. In contrast, long-term contributions to babysitting were not significantly associated with plasma levels of prolactin, cortisol, or testosterone in individual male helpers. Our results show, for the first time, that elevated levels of prolactin may immediately precede bouts of helping behavior but differ from recent findings on the same study population in which plasma levels of cortisol, but not prolactin, were significantly and positively associated with rates of pup feeding by male helpers. Together, these results lend significant weight to the idea that decisions to help in cooperative vertebrates have a hormonal basis, although different hormones appear to be associated with different types of care.

  20. Hyperplastic-like colon polyps that preceded microsatellite-unstable adenocarcinomas.

    PubMed

    Goldstein, Neal S; Bhanot, Punam; Odish, Eva; Hunter, Susan

    2003-06-01

    We compared hyperplastic-like polyps that preceded microsatellite-unstable adenocarcinomas to incidental hyperplastic polyps to identify distinguishing morphologic criteria. The study group included 106 hyperplastic-like, nonadenomatous, serrated polyps, most from the ascending colon in 91 patients; the control group included 106 rectosigmoid hyperplastic polyps from 106 patients in whom adenocarcinoma did not develop. Study group polyps had an expanded crypt proliferative zone, a serrated architectural outline that became apparent in the basilar crypt regions, basilar crypt dilation, inverted crypts, and a predominance of dysmaturational crypts (crypts with minimal cell maturation). In contrast, control group polyps had a proliferative zone confined to the basal crypt region, serrated architecture that became apparent in the superficial crypt region, rare to no basilar crypt dilation, and rare or no dysmaturational crypts. Hyperplastic-like polyps that preceded microsatellite-unstable adenocarcinomas had a distinctive constellation of morphologic features related to altered and decreased cell function and control that resulted in dysmaturational crypts. Dysmaturation constitutes a range of morphologic alterations, some of which overlap with incidental-type innocuous hyperplastic polyps. The morphologic features described herein provide initial guidelines to identify this potentially important subset of premalignant serrated-like polyps.

  1. [The study of precedent subgingival flora colonization on four kinds of crown and bridge restorative materials].

    PubMed

    Gao, N; Zhao, Y; Xiao, X

    1998-02-01

    The purpose of this in vitro study was to investigate the effects of microbial colonization on different crown or fixed bridge-used restorative materials and discuss the standards for evaluating those materials microscopically. Four kinds of restorative materials such as SDA-II type medium alloy, ceramic-fused-to-metal material, heat cure composite resin for crown restoration, Plat castable ceramics and four species of precedent subgingival flora (A. viscosus, F. nucleterm, C. ochracea, S. sanguis) were used. The material specimen had been continuously anaerobic cultured with the experimental bacterial fluid for 3, 7 and 14 days respectively, then the OD values of the specimenwashing fluid which could stand for the biomass of colonized bacteria on the surfaces of materials were measured. The results indicated that the quantity of precedent subgingival flora colonization on the surfaces of different restorative materials varied among different species of bacteria, which might concern with the surface structure, composition, property of anticorrosion and antisoluability of those materials.

  2. The Chicken or the Egg: Examining Temporal Precedence Among Attitudes, Injunctive Norms, and College Student Drinking

    PubMed Central

    Lewis, Melissa A.; Litt, Dana M.; Neighbors, Clayton

    2015-01-01

    Objective: The present study was designed to test for projection, conformity, or reciprocal associations among attitudes, injunctive norms, and drinking. Assuming that these constructs are not independent, we proposed three possible trajectories. A conformity model would suggest that injunctive norms should temporally precede drinking or attitudes. Alternatively, a projection model would suggest that attitudes or alcohol use would precede injunctive norms. Furthermore, by examining the processes over three time points, the current study would also examine whether both conformity and projection processes were at work, indicating reciprocal relationships. Method: participants included 249 college students (63.1% female), who participated as a control group in a larger intervention trial. Structural equation modeling was used to examine cross-sectional and prospective associations among injunctive norms, attitudes, and drinking across each of the three time points. Results: Findings demonstrated three significant cross-lagged associations. Injunctive norms at Time 1 was significantly associated with drinking at Time 2 (conformity), and both attitudes and drinking at Time 2 were significantly associated with injunctive norms at Time 3 (projection). The pattern of cross-lagged associations suggested one meaningful indirect pathway, from Time 1 injunctive norms to Time 2 drinking to Time 3 injunctive norms (reciprocal association). Conclusions: The present study suggests that both the conformity and the projection processes seem to be important and evident for college student drinking when considering injunctive norms and drinking over time. Interventions that focus on both conformity and projection may be particularly effective at reducing longer-term alcohol use. PMID:26098035

  3. [Submucosal Partial-turbinectomy (SPT) Preceding an Endoscopic Sinus Surgery (ESS) Procedure].

    PubMed

    Hirai, Tomohisa; Fukushima, Noriyuki; Miyahara, Nobuyuki; Miyoshi, Ayako; Ariki, Masahiko

    2015-07-01

    Preceding a endoscopic sinus surgery (ESS), we have proposed performing a submucosal partial-turbinectomy (SPT) which removes a part of the inferior nasal concha bone attached to maxillary sinus with an antrostomy. By this method, we could not only make a large antrostomy but also obtain good maneuverability by opening the middle nasal meatus in ESS. We performed SPT preceding ESS in 140 cases (261 sides) between January 2012 and June 2014. The stenosis rates of the middle nasal meatus were 14.2% (37 sides from 261 sides) in one month, 7.4% (18 sides from 243 sides) in three months and 3.7% (6 sides from 163 sides) in 6 months after surgery. The closing rates of the antrostomy were 1.5% (4 sides from 261 sides) in one month, 2.9% (7 sides from 243 sides) in three months and 6.7% (11 sides from 163 sides) in 6 months after surgery. We considered that the SPT method would contribute to secure sufficient ventilation routes for wound healing of sinusitis following surgery on the mucous membrane. In addition, the SPT method has merit from the point of deceasing risks of atrophic rhinitis and empty nose syndrome by preserving most of the inferior nasal concha.

  4. Effects of Prediction and Contextual Support on Lexical Processing: Prediction takes Precedence

    PubMed Central

    Brothers, Trevor; Swaab, Tamara Y.; Traxler, Matthew J.

    2014-01-01

    Readers may use contextual information to anticipate and pre-activate specific lexical items during reading. However, prior studies have not clearly dissociated the effects of accurate lexical prediction from other forms of contextual facilitation such as plausibility or semantic priming. In this study, we measured electrophysiological responses to predicted and unpredicted target words in passages providing varying levels of contextual support. This method was used to isolate the neural effects of prediction from other potential contextual influences on lexical processing. While both prediction and discourse context influenced ERP amplitudes within the time range of the N400, the effects of prediction occurred much more rapidly, preceding contextual facilitation by approximately 100ms. In addition, a frontal, post-N400 positivity (PNP) was modulated by both prediction accuracy and the overall plausibility of the preceding passage. These results suggest a unique temporal primacy for prediction in facilitating lexical access. They also suggest that the frontal PNP may index the costs of revising discourse representations following an incorrect lexical prediction. PMID:25497522

  5. Investigations of the precedence effect in budgerigars: Effects of stimulus type, intensity, duration, and location

    NASA Astrophysics Data System (ADS)

    Dent, Micheal L.; Dooling, Robert J.

    2003-04-01

    Auditory experiments on the localization of sounds in the presence of reflections, or echoes, that arrive later and from different directions are important to understanding hearing in natural environments. The perceived location of the auditory image can change with the time delay between the presentations of a leading and lagging sound. These changes in perceived location, encompassing the precedence effect, have been examined behaviorally or physiologically in humans and a number of animals. Here, these results are extended to include budgerigars. Behavioral methods were used to measure the discrimination performance between a stimulus presented at + and -90° azimuth with a delay (left-), from the same two stimuli presented with the opposite delay (right-left). At short delays, where humans experience summing localization, budgerigars have difficulty discriminating between the two presentation types. With increasing delays, where humans experience localization dominance, budgerigars show improved discrimination performance. At even longer delays, where echo thresholds are found in humans, discrimination performance worsens again. The shapes of the discrimination functions are affected by the intensity, locations, and durations of the stimuli, and are subject to a buildup effect. These results show that budgerigars exhibit the phases of the precedence effect similar to humans and other animals.

  6. Aseismic Slips Preceding Ruptures Assumed for Anomalous Seismicities and Crustal Deformations

    NASA Astrophysics Data System (ADS)

    Ogata, Y.

    2007-12-01

    If aseismic slips occurs on a fault or its deeper extension, both seismicity and geodetic records around the source should be affected. Such anomalies are revealed to have occurred during the last several years leading up to the October 2004 Chuetsu Earthquake of M6.8, the March 2007 Noto Peninsula Earthquake of M6.9, and the July 2007 Chuetsu-Oki Earthquake of M6.8, which occurred successively in the near-field, central Japan. Seismic zones of negative and positive increments of the Coulomb failure stress, assuming such slips, show seismic quiescence and activation, respectively, relative to the predicted rate by the ETAS model. These are further supported by transient crustal movement around the source preceding the rupture. Namely, time series of the baseline distance records between a numbers of the permanent GPS stations deviated from the predicted trend, with the trend of different slope that is basically consistent with the horizontal displacements of the stations due to the assumed slips. References Ogata, Y. (2007) Seismicity and geodetic anomalies in a wide area preceding the Niigata-Ken-Chuetsu Earthquake of October 23, 2004, central Japan, J. Geophys. Res. 112, in press.

  7. Homologous pairing preceding SPO11-mediated double-strand breaks in mice.

    PubMed

    Boateng, Kingsley A; Bellani, Marina A; Gregoretti, Ivan V; Pratto, Florencia; Camerini-Otero, R Daniel

    2013-01-28

    How homologous chromosomes (homologs) find their partner, pair, and recombine during meiosis constitutes the central phenomenon in eukaryotic genetics. It is widely believed that, in most organisms, SPO11-mediated DNA double-strand breaks (DSBs) introduced during prophase I precede and are required for efficient homolog pairing. We now show that, in the mouse, a significant level of homolog pairing precedes programmed DNA cleavage. Strikingly, this early chromosome pairing still requires SPO11 but is not dependent on its ability to make DSBs or homologous recombination proteins. Intriguingly, SUN1, a protein required for telomere attachment to the nuclear envelope and for post-DSB synapsis, is also required for early pre-DSB homolog pairing. Furthermore, pre-DSB pairing at telomeres persists upon entry into prophase I and is most likely important for initiation of synapsis. Our findings suggest that the DSB-triggered homology search may mainly serve to proofread and stabilize the pre-DSB pairing of homologous chromosomes.

  8. Force-dependent calcium signaling and its pathway of human neutrophils on P-selectin in flow.

    PubMed

    Huang, Bing; Ling, Yingchen; Lin, Jiangguo; Du, Xin; Fang, Ying; Wu, Jianhua

    2017-02-01

    P-selectin engagement of P-selectin glycoprotein ligand-1 (PSGL-1) causes circulating leukocytes to roll on and adhere to the vascular surface, and mediates intracellular calcium flux, a key but unclear event for subsequent arresting firmly at and migrating into the infection or injured tissue. Using a parallel plate flow chamber technique and intracellular calcium ion detector (Fluo-4 AM), the intracellular calcium flux of firmly adhered neutrophils on immobilized P-selectin in the absence of chemokines at various wall shear stresses was investigated here in real time by fluorescence microscopy. The results demonstrated that P-selectin engagement of PSGL-1 induced the intracellular calcium flux of firmly adhered neutrophils in flow, increasing P-selectin concentration enhanced cellular calcium signaling, and, force triggered, enhanced and quickened the cytoplasmic calcium bursting of neutrophils on immobilized P-selectin. This P-selectin-induced calcium signaling should come from intracellular calcium release rather than extracellular calcium influx, and be along the mechano-chemical signal pathway involving the cytoskeleton, moesin and Spleen tyrosine kinase (Syk). These results provide a novel insight into the mechano-chemical regulation mechanism for P-selectin-induced calcium signaling of neutrophils in flow.

  9. Calcium supplement: humanity's double-edged sword.

    PubMed

    Bunyaratavej, Narong; Buranasinsup, Shutipen

    2011-10-01

    The principle aim of the present study is to investigate the dark side of calcium, pollutions in calcium preparation especially lead (Pb), mercury (Hg) and cadmium (Cd). The collected samples were the different calcium salts in the market and 18 preparations which were classified into 3 groups: Calcium carbonate salts, Chelated calcium and natural-raw calcium. All samples were analyzed for lead, cadmium and mercury by inductively Coupled Plasma Mass Spectrometry (ICP-MS) technique, in house method based on AOAC (2005) 999.10 by ICP-MS. The calcium carbonate and the natural-raw calcium in every sample contained lead at 0.023-0.407 mg/kg of calcium powder. Meanwhile, the natural-raw calcium such as oyster, coral and animal bone showed amount of lead at 0.106-0.384 mg/kg with small amounts of mercury and cadmium. The chelated calcium such as calcium gluconate, calcium lactate and calcium citrate are free of lead.

  10. Calcium bioavailability and its relation to osteoporosis.

    PubMed

    Weaver, C M

    1992-06-01

    The balance of data suggests that calcium intake has a positive influence on bone mass in premenopausal women and has a preventive effect on the rate of bone loss in postmenopausal women. Even small advantages in bone mass provide great reductions in fracture rates. However, the majority of studies have tested the relationship of calcium intake and bone mass using calcium supplements. Few intervention studies have manipulated calcium intake through foods. Calcium is only useful to the skeleton once it is absorbed. Therefore, the bioavailability of dietary calcium becomes important in the prevention and treatment of osteoporosis. Isotopic tracer techniques have only recently been employed in the labeling of foods with calcium isotopes for evaluation of calcium absorption. Milk calcium is usually the referent food which is typically absorbed at 20-40% depending on the calcium status of the subject. The absorptive efficiency of most vegetable sources is as good or better than for dairy foods, unless they have high concentrations of oxalic acid (spinach, for example) or phytic acid (wheat bran cereal, for example). Few vegetable sources are concentrated sources of calcium. Therefore, it would be difficult to obtain adequate intakes of calcium to protect against osteoporosis without liberal use of dairy products in the diet. Alternately, calcium supplements provide concentrated amounts of absorbable calcium, but they do not provide other nutrients necessary for skeletal growth and maintenance.

  11. Influence of phosvitin and calcium gluconate concentration on permeation and intestinal absorption of calcium ions.

    PubMed

    Dolińska, Barbara; Łopata, Katarzyna; Mikulska, Agnieszka; Leszczyńska, Lucyna; Ryszka, Florian

    2012-06-01

    The effect of egg yolk phosvitin on the permeation and absorption of calcium was investigated in vitro in relation to calcium gluconate concentration. Obtained results indicate that phosvitin significantly reduces the intestinal calcium absorption from 1 and 10 mM of calcium gluconate solution. It is associated with the formation of the complex of Ca (II) ions with phosvitin. The process of calcium permeation increases under phosvitin influence when calcium gluconate concentrations rise up to 10 mM. At a higher concentration of calcium gluconate (20 mM), no effect of phosvitin was seen on permeation of calcium ions.

  12. Preceding infection as an important risk factor for ischaemic brain infarction in young and middle aged patients

    PubMed Central

    Syrjänen, Jaana; Valtonen, Ville V; Iivanainen, Matti; Kaste, Markku; Huttunen, Jussi K

    1988-01-01

    The role of preceding infection as a risk factor for ischaemic stroke was investigated in a case-control study of 54 consecutive patients under 50 years of age with brain infarction and 54 randomly selected controls from the community matched for sex and age. Information about previous illnesses, smoking, consumption of alcohol, and use of drugs was taken. A blood sample was analysed for standard biochemical variables and serum cholesterol, high density lipoprotein cholesterol, triglyceride, and fasting blood glucose concentrations determined. Titres of antimicrobial antibodies against various bacteria, including Staphylococcus, Streptococcus, Yersinia, and Salmonella and several viruses were determined. Febrile infection was found in patients during the month before the brain infarction significantly more often than in controls one month before their examination (19 patients v three controls; estimated relative risk 9·0 (95% confidence interval 2·2 to 80·0)). The most common preceding febrile infection was respiratory infection (80%). Infections preceding brain infarction were mostly of bacterial origin based on cultural, serological, and clinical data. In conditional logistic regression analysis for matched pairs the effect of preceding febrile infection remained significant (estimated relative risk 14·5 (95% confidence interval 1·9 to 112·3)) when tested with triglyceride concentration, hypertension, smoking, and preceding intoxication with alcohol. Although causality cannot be inferred from these data and plausible underlying mechanisms remain undetermined, preceding febrile infection may play an important part in the development of brain infarction in young and middle aged patients. PMID:3132245

  13. Seed Population in Large Solar Energetic Particle Events and the Twin-CME Scenario

    NASA Astrophysics Data System (ADS)

    Ding, Liu-Guan; Li, Gang; Le, Gui-Ming; Gu, Bin; Cao, Xin-Xin

    2015-10-01

    It has recently been suggested that large solar energetic particle (SEP) events are often caused by twin coronal mass ejections (CMEs). In the twin-CME scenario, the preceding CME provides both an enhanced turbulence level and enhanced seed population at the main CME-driven shock. In this work, we study the effect of the preceding CMEs on the seed population. We examine event-integrated abundance of iron to oxygen ratio (Fe/O) at energies above 25 MeV/nuc for large SEP events in solar cycle 23. We find that the Fe/O ratio (normalized to the reference coronal value of 0.134) ≤2.0 for almost all single-CME events and these events tend to have smaller peak intensities. In comparison, the Fe/O ratio of twin-CME events scatters in a larger range, reaching as high as 8, suggesting the presence of flare material from perhaps preceding flares. For extremely large SEP events with peak intensities above 1000 pfu, the Fe/O ratios drop below 2, indicating that the seed particles are dominated by coronal material rather than flare material in these extreme events. The Fe/O ratios of ground level enhancement (GLE) events, which are all twin-CME events, scatter in a broad range. For a given Fe/O ratio, GLE events tend to have larger peak intensities than non-GLE events. Using velocity dispersion analysis, we find that GLE events have lower solar particle release heights than non-GLE events, agreeing with earlier results by Reames.

  14. Development of Dilated Cardiomyopathy and Impaired Calcium Homeostasis with Cardiac-Specific Deletion of ESRRβ.

    PubMed

    Rowe, Glenn C; Asimaki, Angeliki; Graham, Evan L; Martin, Kimberly D; Margulies, Kenneth B; Das, Saumya; Saffitz, Jeffrey E; Arany, Zoltan

    2017-01-27

    Mechanisms underlying the development of Idiopathic Dilated Cardiomyopathy (DCM) remain poorly understood. Using transcription factor expression profiling, we identified estrogen-related receptor beta (ESRRβ), a member of the nuclear receptor family of transcription factors, as highly expressed in murine hearts and other highly oxidative striated muscle beds. Mice bearing cardiac-specific deletion of ESRRβ (MHC-ERRB KO) develop dilated cardiomyopathy and sudden death at approximately 10 months of age. Isolated adult cardiomyocytes from the MHC-ERRB KO mice showed an increase in calcium sensitivity and impaired cardiomyocyte contractility, which preceded echocardiographic cardiac remodeling and dysfunction by several months. Histological analyses of myocardial biopsies from patients with various cardiomyopathies revealed that ESRRβ protein is absent from the nucleus of cardiomyocytes from patients with DCM, but not other forms of cardiomyopathy (ischemic, hypertrophic and arrhythmogenic right ventricular cardiomyopathy). Taken together these observations suggest that ESRRβ is a critical component in the onset of dilated cardiomyopathy by affecting contractility and calcium balance.

  15. Elastin Degradation and Vascular Smooth Muscle Cell Phenotype Change Precede Cell Loss and Arterial Medial Calcification in a Uremic Mouse Model of Chronic Kidney Disease

    PubMed Central

    Pai, Ashwini; Leaf, Elizabeth M.; El-Abbadi, Mohga; Giachelli, Cecilia M.

    2011-01-01

    Arterial medial calcification (AMC), a hallmark of vascular disease in uremic patients, is highly correlated with serum phosphate levels and cardiovascular mortality. To determine the mechanisms of AMC, mice were made uremic by partial right-side renal ablation (week 0), followed by left-side nephrectomy at week 2. At 3 weeks, mice were switched to a high-phosphate diet, and various parameters of disease progression were examined over time. Serum phosphate, calcium, and fibroblast growth factor 23 (FGF-23) were up-regulated as early as week 4. Whereas serum phosphate and calcium levels declined to normal by 10 weeks, FGF-23 levels remained elevated through 16 weeks, consistent with an increased phosphate load. Elastin turnover and vascular smooth muscle cell (VSMC) phenotype change were early events, detected by week 4 and before AMC. Both AMC and VSMC loss were significantly elevated by week 8. Matrix metalloprotease 2 (MMP-2) and cathepsin S were present at baseline and were significantly elevated at weeks 8 and 12. In contrast, MMP-9 was not up-regulated until week 12. These findings over time suggest that VSMC phenotype change and VSMC loss (early phosphate-dependent events) may be necessary and sufficient to promote AMC in uremic mice fed a high-phosphate diet, whereas elastin degradation might be necessary but is not sufficient to induce AMC (because elastin degradation occurred also in uremic mice on a normal-phosphate diet, but they did not develop AMC). PMID:21281809

  16. Pathogenesis and treatment of calcium stones.

    PubMed

    Parks, J H; Coe, F L

    1996-09-01

    Calcium stones arise from imbalances between urinary excretions of insoluble salts and water. Idiopathic hypercalciuria and hyperparathyroidism are the calcium disorders usually associated with elevated levels of calcium in the urine. Renal tubular acidosis is associated with a disordered acid-base status that results in low urine citrate. Hypocitraturia itself is a cause of calcium stones because it leaves urine calcium free to complex with either oxalate or phosphate. Elevated urine oxalate is commonly associated with dietary excesses, bowel disease, and, rarely, primary hyperoxaluria. Hyperuricosuria, usually of dietary origin, when reversed can cause a fall in new calcium stones.

  17. Calcium supplementation during sepsis exacerbates organ failure and mortality via calcium/calmodulin-dependent protein kinase kinase (CaMKK) signaling

    PubMed Central

    Collage, Richard D.; Howell, Gina M.; Zhang, Xianghong; Stripay, Jennifer L.; Lee, Janet S.; Angus, Derek C.; Rosengart, Matthew R.

    2013-01-01

    Background Calcium plays an essential role in nearly all cellular processes. As such, cellular and systemic calcium concentrations are tightly regulated. During sepsis derangements in such tight regulation frequently occur, and treating hypocalcemia with parenteral calcium administration remains the current practice guideline. Objective We investigated whether calcium administration worsens mortality and organ dysfunction using an experimental murine model of sepsis and explored the mechanistic role of the family of calcium/calmodulin-dependent protein kinases in mediating these physiologic effects. To highlight the biological relevance of these observations, we conducted a translational study of the association between calcium administration, organ dysfunction and mortality among a cohort of critically ill septic ICU patients Design Prospective, randomized controlled experimental murine study. Observational clinical cohort analysis. Setting University research laboratory. Eight ICUs at a tertiary care center. Patients 870 septic ICU patients. Subjects C57BL/6 and CaMKK−/− mice. Interventions Mice underwent cecal ligation and puncture polymicrobial sepsis and were administered calcium chloride (0.25 or 0.25 mg/kg) or normal saline. Measurements and Main Results Administering calcium chloride to septic C57BL/6 mice heightened systemic inflammation and vascular leak, exacerbated hepatic and renal dysfunction, and increased mortality. These events were significantly attenuated in CaMKK−/− mice. In a risk–adjusted analysis of septic patients, calcium administration was associated with an increased risk of death, OR 1.92 (95% CI 1.00–3.68, p=0.049), a significant increase in the risk of renal dysfunction, OR 4.74 (95% CI 2.48–9.08, p<0.001), and a significant reduction in ventilator free days, mean decrease 3.29 days (0.50–6.08 days, p=0.02). Conclusions Derangements in calcium homeostasis occur during sepsis that are sensitive to calcium administration

  18. Calcium Sparks in the Heart: Dynamics and Regulation

    PubMed Central

    Hoang-Trong, Tuan M.; Ullah, Aman; Jafri, M. Saleet

    2016-01-01

    Calcium (Ca2+) plays a central role in the contraction of the heart. It is the bi-directional link between electrical excitation of the heart and contraction. Electrical excitation initiates Ca2+influx across the sarcolemma and T-tubular membrane that triggered calcium release from the sarcoplasmic reticulum. Ca2+sparks are the elementary events of calcium release from the sarcoplasmic reticulum. Therefore, understanding the dynamics of Ca2+sparks is essential for understanding the function of the heart. To this end, numerous experimental and computational studies have focused on this topic, exploring the mechanisms of calcium spark initiation, termination, and regulation and what role these play in normal and patho-physiology. The proper understanding of Ca2+ spark regulation and dynamics serves as the foundation for our insights into a multitude of pathological conditions may develop that can be the result of structural and/or functional changes at the cellular or subcellular level. Computational modeling of Ca2+ spark dynamics has proven to be a useful tool to understand Ca2+ spark dynamics. This review addresses our current understanding of Ca2+ sparks and how synchronized SR Ca2+ release, in which Ca2+ sparks is a major pathway, is linked to the different cardiac diseases, especially arrhythmias. PMID:27212876

  19. Earth's magnetic field anomalies that precede the M6+ global seismic activity

    NASA Astrophysics Data System (ADS)

    Cataldi, Gabriele; Cataldi, Daniele; Straser, Valentino

    2014-05-01

    In this work has been analyzed the Earth's magnetic field variations and the M6+ global seismic activity to verify if M6+ earthquakes are preceded by a change of the Earth's magnetic field. The data of Earth's magnetic field used to conduct the study of correlation are provided by the induction magnetometer of Radio Emissions Project's station (Lat: 41°41'4.27"N, Long: 12°38'33,60"E, Albano Laziale, Rome, Italy), equipped with a ELF receiver prototype (with a vertically aligned coil antenna) capable to detect the variations of the intensity of the Earth's magnetic field on Z magnetic component. The M6+ global seismic activity data are provided in real-time by USGS, INGV and CSEM. The sample of data used to conduct the study refers to the period between 1 January 2012 and 31 December 2012. The Earth's magnetic field variations data set has been marked with the times (time markers) of M6+ earthquakes occurred on a global scale and has been verified the existence of disturbances of the Earth's geomagnetic field in the time interval that preceded the M6+ global seismic activity. The correlation study showed that all M6+ earthquakes recorded on 2012 were preceded by an increase of the Earth's magnetic field, detected in the Z magnetic component. The authors measured the time lag elapsed between the maximum increment of the Earth's magnetic field recorded before an earthquake M6+ and the date and time at which this occurred, and has been verified that the minimum time lag recorded between the Earth's magnetic field increase and the earthquake M6+ has been 1 minute (9 October 2012, Balleny Islands, M6,4); while, the maximum time lag recorded has been 3600 minutes (26 June 2012, China, M6,3). The average time lag has been 629.47 minutes. In addition, the average time lag is deflected in relation to the magnitude increase. Key words: Seismic Geomagnetic Precursor (SGP), Interplanetary Seismic Precursor (ISP), Earth's magnetic field variations, earthquakes, prevision.

  20. Physiological correlates of the precedence effect and summing localization in the inferior colliculus of the cat.

    PubMed

    Yin, T C

    1994-09-01

    The precedence effect (PE) describes an illusion produced when two similar sounds are delivered in quick succession (interclick delays of 2-8 msec) from sound sources at different locations so that only a single sound is perceived. The localization of the perceived sound is dominated by the location of the leading sound. If the delays are very short (< 1-2 msec), summing localization occurs and a phantom source is perceived whose location is toward the leading sound. The purpose of these experiments was to look for physiological correlates of the precedence effect and summing localization by recording from single neurons in the inferior colliculus of the anesthetized cat. Click stimuli were delivered under two different situations: over headphones in dichotic experiments and through two speakers in an anechoic room in free-field studies. In the latter case the cat was placed midway between the speakers and a single click stimulus was delivered to each speaker with variable interclick delays (ICDs). Most cells, under both dichotic and free-field conditions, exhibited a form of the precedence effect in which the response to the lagging click was suppressed when ICDs were short. The suppression of the lagging click, or echo, was measured by recovery curves, which plotted the response of the lagging click as a function of ICD. There was considerable variability in the recovery curves from different cells: the ICDs at which the recovery reached 50%, which is a measure of the echo threshold for the cell, ranged from 1 to 100 msec with a median of 20 msec. Human psychophysical experiments report echo thresholds for clicks ranging from 2 to 8 msec. If we assume that absolute echo threshold is determined by the cells with shortest recovery curves, then the thresholds for single cells are in accord with the psychophysical results. The possible sites of generation of the echo suppression are also considered. Changes in the relative level of the leading and lagging clicks

  1. Wavelet principal component analysis of fetal movement counting data preceding hospital examinations due to decreased fetal movement: a prospective cohort study

    PubMed Central

    2013-01-01

    Background Fetal movement (FM) counting is a simple and widely used method of assessing fetal well-being. However, little is known about what women perceive as decreased fetal movement (DFM) and how maternally perceived DFM is reflected in FM charts. Methods We analyzed FM counting data from 148 DFM events occurring in 137 pregnancies. The women counted FM daily from pregnancy week 24 until birth using a modified count-to-ten procedure. Common temporal patterns for the two weeks preceding hospital examination due to DFM were extracted from the FM charts using wavelet principal component analysis; a statistical methodology particularly developed for modeling temporal data with sudden changes, i.e. spikes that are frequently found in FM data. The association of the extracted temporal patterns with fetal complications was assessed by including the individuals’ scores on the wavelet principal components as explanatory variables in multivariable logistic regression analyses for two outcome measures: (i) complications identified during DFM-related consultations (n = 148) and (ii) fetal compromise at the time of consultation (including relevant information about birth outcome and placental pathology). The latter outcome variable was restricted to the DFM events occurring within 21 days before birth (n = 76). Results Analyzing the 148 and 76 DFM events, the first three main temporal FM counting patterns explained 87.2% and 87.4%, respectively, of all temporal variation in the FM charts. These three temporal patterns represented overall counting times, sudden spikes around the time of DFM events, and an inverted U-shaped pattern, explaining 75.3%, 8.6%, and 3.3% and 72.5%, 9.6%, and 5.3% of variation in the total cohort and subsample, respectively. Neither of the temporal patterns was significantly associated with the two outcome measures. Conclusions Acknowledging that sudden, large changes in fetal activity may be underreported in FM charts, our study showed that the

  2. The effect of variable calcium and very low calcium diets on human calcium metabolism. Ph.D. Thesis. Final Report

    NASA Technical Reports Server (NTRS)

    Chu, J.

    1971-01-01

    The effects of a very low calcium diet, with variable high and low protein intake, on the dynamics of calcium metabolism and the mechanism of calciuretics, are examined. The experiment, using male subjects, was designed to study the role of intestinal calcium absorption on urinary calcium excretion, and the rate of production of endogeneously secreted calcium in the gastrointestinal tract. The study showed an average of 70% fractional absorption rate during very low calcium intake, and that a decrease in renal tubular reabsorption of calcium is responsible for calciuretic effects of high protein intake. The study also indicates that there is a tendency to develop osteoporosis after long periods of low calcium intake, especially with a concurrent high protein intake.

  3. Calcium regulation of muscle contraction.

    PubMed Central

    Szent-Györgyi, A G

    1975-01-01

    Calcium triggers contraction by reaction with regulatory proteins that in the absence of calcium prevent interaction of actin and myosin. Two different regulatory systems are found in different muscles. In actin-linked regulation troponin and tropomyosin regulate actin by blocking sites on actin required for complex formation with myosin; in myosin-linked regulation sites on myosin are blocked in the absence of calcium. The major features of actin control are as follows: there is a requirement for tropomyosin and for a troponin complex having three different subunits with different functions; the actin displays a cooperative behavior; and a movement of tropomyosin occurs controlled by the calcium binding on troponin. Myosin regulation is controlled by a regulatory subunit that can be dissociated in scallop myosin reversibly by removing divalent cations with EDTA. Myosin control can function with pure actin in the absence of tropomyosin. Calcium binding and regulation of molluscan myosins depend on the presence of regulatory light chains. It is proposed that the light chains function by sterically blocking myosin sites in the absence of calcium, and that the "off" state of myosin requires cooperation between the two myosin heads. Both myosin control and actin control are widely distributed in different organisms. Many invertebrates have muscles with both types of regulation. Actin control is absent in the muscles of molluscs and in several minor phyla that lack troponin. Myosin control is not found in striated vertebrate muscles and in the fast muscles of crustacean decapods, although regulatory light chains are present. While in vivo myosin control may not be excluded from vertebrate striated muscles, myosin control may be absent as a result of mutations of the myosin heavy chain. PMID:806311

  4. Some anomalous behaviour of vertebrates and insects preceding M5+ earthquakes in the North Western Apennines (Italy)

    NASA Astrophysics Data System (ADS)

    Straser, Valentino

    2013-04-01

    Earthquakes with a magnitude greater than M5+ are an unusual event in the seismic area of the Frignano District and the areas surrounding Parma in the North Western Apennines (Italy). Only two seismic events have occurred in the last four years: on 23 December 2008 (M5.1) and on 27 January 2012 (M5.4). The earthquake of 23 December 2008 allowed the verification of unusual behaviour in man and animals in the run-up to the main shock, in addition to anomalies of an electromagnetic type. An initial study showed that there are elements of coincidence between the seismic events and the number of admissions to hospitals around the epicentre: in the month of December 2008, the days with the greatest number of admissions coincided with seismic shocks. A half hour before the main event of 23 December, recorded at 16:24:21 local time (see: INGV), a slowworm (Anguis fragilis) left its hibernation site and died shortly afterwards from the cold on a road, as did a viper (Vipera aspis) found near some dwellings in an area around twenty kilometres from the epicentre. The investigation proceeded in 2009, but this time based on the number of daily admissions to the hospital A&E department, between June and December 2009. During the six months of the investigation, the maximum number of emergencies was 9 per day, while the earthquakes were in line with the usual number and magnitude for the Frignano seismic district. The earthquakes from June to December 2009 numbered 10, with a magnitude from M2.5 to M3.6. In 8 cases, in the 48 hours preceding the occurrence of the seism, there was a greater number of hospital emergencies. The subsequent occasion to check on a possible relationship between anomalous behaviour in animals and a seism occurred on 27 January 2012 (see: INGV), when an earthquake with a magnitude of M5.4 shook the North Western Apennines, thankfully without resulting in victims. Like 2008, in an area around fifteen kilometres from the epicentre, a grass snake (Zamenis

  5. Vitamin D and intestinal calcium absorption.

    PubMed

    Christakos, Sylvia; Dhawan, Puneet; Porta, Angela; Mady, Leila J; Seth, Tanya

    2011-12-05

    The principal function of vitamin D in calcium homeostasis is to increase calcium absorption from the intestine. Calcium is absorbed by both an active transcellular pathway, which is energy dependent, and by a passive paracellular pathway through tight junctions. 1,25Dihydroxyvitamin D(3) (1,25(OH)(2)D(3)) the hormonally active form of vitamin D, through its genomic actions, is the major stimulator of active intestinal calcium absorption which involves calcium influx, translocation of calcium through the interior of the enterocyte and basolateral extrusion of calcium by the intestinal plasma membrane pump. This article reviews recent studies that have challenged the traditional model of vitamin D mediated transcellular calcium absorption and the crucial role of specific calcium transport proteins in intestinal calcium absorption. There is also increasing evidence that 1,25(OH)(2)D(3) can enhance paracellular calcium diffusion. The influence of estrogen, prolactin, glucocorticoids and aging on intestinal calcium absorption and the role of the distal intestine in vitamin D mediated intestinal calcium absorption are also discussed.

  6. Learning to Describe Events.

    ERIC Educational Resources Information Center

    Duchan, Judith Felson

    1986-01-01

    The article discusses language structures of three hierarchical levels of event descriptions: (1) single-action events (semantic relations, aspectual meaning and lexical verbs or verb phrases, (2) event relations (tense markers, conjunctions, adverbs, perfect tense); (3) event schemas (lexical terms and phrases marking beginnings and endings). A…

  7. Orbitofrontal Cortex Biases Attention to Emotional Events

    PubMed Central

    Hartikainen, K.M.; Ogawa, K.H.; Knight, R.T.

    2012-01-01

    We examined the role of orbitofrontal (OF) cortex in regulating emotion-attention interaction and the balance between involuntary and voluntary attention allocation. We studied patients with OF lesion applying reaction time (RT) and event-related potential (ERP) measures in a lateralized visual discrimination task with novel task-irrelevant affective pictures (unpleasant, pleasant or neutral) preceding a neutral target. This allowed for comparing the effects of automatic attention allocation to emotional vs neutral stimuli on subsequent voluntary attention allocation to target stimuli. N2-P3a and N2-P3b ERP components served as measures of involuntary and voluntary attention allocation correspondingly. Enhanced N2-P3a amplitudes to emotional distractors and reduced N2-P3b amplitudes to targets preceded by emotional distractors were observed in healthy subjects, suggesting automatic emotional orienting interfered with subsequent voluntary orienting. OF patients showed an opposite pattern with tendency towards reduced N2-P3a responses to emotional distractors, suggesting impaired automatic orienting to emotional stimuli due to orbitofrontal damage. Enhanced N2-P3b responses to targets preceded by any affective distractor was observed in OF patients, suggesting bias towards voluntary target-related attention allocation due to orbitofrontal lesion. Behavioral evidence indicated that LVF attention performance was modulated by emotional stimuli. Specifically, OF patients responded faster to LVF targets subsequent to pleasant emotional distractors. We suggest damage to the orbitofrontal circuitry leads to dysbalance between voluntary and involuntary attention allocation in the context of affective distracters with predisposition to posterior target related processing over frontal novelty and affect related processing. Furthermore, we suggest orbitofrontal influence on emotion- attention interaction is valence and hemisphere dependent. PMID:22413757

  8. The role of calcium in the prevention of cardiovascular disease--a review of observational studies and randomized clinical trials.

    PubMed

    Rautiainen, Susanne; Wang, Lu; Manson, JoAnn E; Sesso, Howard D

    2013-11-01

    Calcium is a mineral that is important for bone health and has also been suggested to play a role in the prevention of cardiovascular disease (CVD). Lately, the potential effects of both inadequate and excessive calcium intake have received growing attention. In this review, we summarize the evidence from experimental, epidemiologic, and clinical studies investigating the role of calcium intake, either from the diet or from supplements, as well as blood concentrations, in relation to the risk of CVD in adults. In vitro and in vivo laboratory studies suggest that calcium may be involved in CVD development through multiple pathways, including blood cholesterol, insulin secretion and sensitivity, vasodilation, inflammatory profile, thrombosis, obesity, and vascular calcification. Several prospective epidemiologic studies have examined how dietary or supplemental calcium intake is associated with CVD incidence or mortality in middle-aged and older adults, and the results are inconsistent. Prospective studies investigating blood concentrations of calcium have also reported mixed results. However, changes in blood calcium concentrations may reflect a disturbed calcium phosphate balance, which is associated with increased risk of CVD. To date there is no randomized clinical trial that has been designed specifically to test the effect of calcium supplementation on the risk of CVD as the primary end point. Existing trials have performed secondary analyses, and most of them have been conducted among postmenopausal women. These trials suggest that calcium supplementation has no effect on CVD development; however, they do not allow a definitive conclusion to be drawn. The average daily intake of calcium is low in many populations; however, the evidence for a potential role of dietary or supplemental calcium in the prevention of CVD remains insufficient and inconclusive. Only large-scale randomized trials designed to investigate the effects of calcium supplementation on CVD

  9. Calcium-acting drugs modulate expression and development of chronic tolerance to nicotine-induced antinociception in mice.

    PubMed

    Damaj, M I

    2005-11-01

    Initial studies in our laboratory suggested that tolerance to nicotine is thought to involve neuronal adaptation not only at the level of the drug-receptor interaction but at postreceptor events such as calcium-dependent second messengers. The present study was undertaken to investigate the hypothesis that L-type calcium channels and calcium-dependent calmodulin protein kinase II are involved in the development and expression of nicotine tolerance. To that end, the effects of modulation of L-type calcium channels (through the use of inhibitors or activators) as well as calcium-dependent calmodulin protein kinase II inactivation were studied in a mouse model of tolerance where mice were infused with nicotine in minipumps (24 mg/kg/day) for 14 days. In addition, the activity of calcium-dependent calmodulin protein kinase II in the lumbar spinal cord region obtained from nicotine-tolerant mice was measured. Our data showed that chronic administration of L-type calcium channel antagonists nimodipine (1 and 5 mg/kg) and verapamil (10 mg/kg) prevented the development of tolerance to nicotine-induced antinociception. In contrast, chronic exposure of BAYK8644 [(+/-)-1,4-dihydro-2,6-dimethyl-5-nitro-4-[2-(trifluoromethyl)-phenyl]-3-pyridine carboxylic acid methyl ester], a calcium channel activator, enhanced nicotine's tolerance. Moreover, a significant increase in both dependent and independent calcium-dependent calmodulin protein kinase II activity was seen in the spinal cord in nicotine-tolerant mice. Finally, spinal administration of 1-[N,O-bis(5-isoquinolinesulfonyl)-N-methyl-tyrosyl]-4-phenylpiperazine (KN-62), a calcium-dependent calmodulin protein kinase II antagonist, reduced the expression of tolerance to nicotine-induced antinociception in mice. In conclusion, our data indicate that calcium-dependent mechanisms such as L-type calcium channels and calcium-dependent calmodulin protein kinase II activation are involved in the expression and development of nicotine

  10. Temporal Precedence Checking for Switched Models and its Application to a Parallel Landing Protocol

    NASA Technical Reports Server (NTRS)

    Duggirala, Parasara Sridhar; Wang, Le; Mitra, Sayan; Viswanathan, Mahesh; Munoz, Cesar A.

    2014-01-01

    This paper presents an algorithm for checking temporal precedence properties of nonlinear switched systems. This class of properties subsume bounded safety and capture requirements about visiting a sequence of predicates within given time intervals. The algorithm handles nonlinear predicates that arise from dynamics-based predictions used in alerting protocols for state-of-the-art transportation systems. It is sound and complete for nonlinear switch systems that robustly satisfy the given property. The algorithm is implemented in the Compare Execute Check Engine (C2E2) using validated simulations. As a case study, a simplified model of an alerting system for closely spaced parallel runways is considered. The proposed approach is applied to this model to check safety properties of the alerting logic for different operating conditions such as initial velocities, bank angles, aircraft longitudinal separation, and runway separation.

  11. Basal forebrain degeneration precedes and predicts the cortical spread of Alzheimer's pathology

    PubMed Central

    Schmitz, Taylor W.; Nathan Spreng, R.; Weiner, Michael W.; Aisen, Paul; Petersen, Ronald; Jack, Clifford R.; Jagust, William; Trojanowki, John Q.; Toga, Arthur W.; Beckett, Laurel; Green, Robert C.; Saykin, Andrew J.; Morris, John; Shaw, Leslie M.; Khachaturian, Zaven; Sorensen, Greg; Kuller, Lew; Raichle, Marc; Paul, Steven; Davies, Peter; Fillit, Howard; Hefti, Franz; Holtzman, Davie; Mesulam, M Marcel; Potter, William; Snyder, Peter; Schwartz, Adam; Montine, Tom; Thomas, Ronald G.; Donohue, Michael; Walter, Sarah; Gessert, Devon; Sather, Tamie; Jiminez, Gus; Harvey, Danielle; Bernstein, Matthew; Fox, Nick; Thompson, Paul; Schuff, Norbert; Borowski, Bret; Gunter, Jeff; Senjem, Matt; Vemuri, Prashanthi; Jones, David; Kantarci, Kejal; Ward, Chad; Koeppe, Robert A.; Foster, Norm; Reiman, Eric M.; Chen, Kewei; Mathis, Chet; Landau, Susan; Cairns, Nigel J.; Householder, Erin; Taylor-Reinwald, Lisa; Lee, Virginia; Korecka, Magdalena; Figurski, Michal; Crawford, Karen; Neu, Scott; Foroud, Tatiana M.; Potkin, Steven; Shen, Li; Faber, Kelley; Kim, Sungeun; Nho, Kwangsik; Thal, Leon; Buckholtz, Neil; Albert, Marylyn; Frank, Richard; Hsiao, John; Kaye, Jeffrey; Quinn, Joseph; Lind, Betty; Carter, Raina; Dolen, Sara; Schneider, Lon S.; Pawluczyk, Sonia; Beccera, Mauricio; Teodoro, Liberty; Spann, Bryan M.; Brewer, James; Vanderswag, Helen; Fleisher, Adam; Heidebrink, Judith L.; Lord, Joanne L.; Mason, Sara S.; Albers, Colleen S.; Knopman, David; Johnson, Kris; Doody, Rachelle S.; Villanueva-Meyer, Javier; Chowdhury, Munir; Rountree, Susan; Dang, Mimi; Stern, Yaakov; Honig, Lawrence S.; Bell, Karen L.; Ances, Beau; Carroll, Maria; Leon, Sue; Mintun, Mark A.; Schneider, Stacy; Oliver, Angela; Marson, Daniel; Griffith, Randall; Clark, David; Geldmacher, David; Brockington, John; Roberson, Erik; Grossman, Hillel; Mitsis, Effie; de Toledo-Morrell, Leyla; Shah, Raj C.; Duara, Ranjan; Varon, Daniel; Greig, Maria T.; Roberts, Peggy; Albert, Marilyn; Onyike, Chiadi; D'Agostino, Daniel; Kielb, Stephanie; Galvin, James E.; Cerbone, Brittany; Michel, Christina A.; Rusinek, Henry; de Leon, Mony J.; Glodzik, Lidia; De Santi, Susan; Doraiswamy, P. Murali; Petrella, Jeffrey R.; Wong, Terence Z.; Arnold, Steven E.; Karlawish, Jason H.; Wolk, David; Smith, Charles D.; Jicha, Greg; Hardy, Peter; Sinha, Partha; Oates, Elizabeth; Conrad, Gary; Lopez, Oscar L.; Oakley, MaryAnn; Simpson, Donna M.; Porsteinsson, Anton P.; Goldstein, Bonnie S.; Martin, Kim; Makino, Kelly M.; Ismail, M. Saleem; Brand, Connie; Mulnard, Ruth A.; Thai, Gaby; Mc-Adams-Ortiz, Catherine; Womack, Kyle; Mathews, Dana; Quiceno, Mary; Diaz-Arrastia, Ramon; King, Richard; Weiner, Myron; Martin-Cook, Kristen; DeVous, Michael; Levey, Allan I.; Lah, James J.; Cellar, Janet S.; Burns, Jeffrey M.; Anderson, Heather S.; Swerdlow, Russell H.; Apostolova, Liana; Tingus, Kathleen; Woo, Ellen; Silverman, Daniel H. S.; Lu, Po H.; Bartzokis, George; Graff-Radford, Neill R.; Parfitt, Francine; Kendall, Tracy; Johnson, Heather; Farlow, Martin R.; Hake, AnnMarie; Matthews, Brandy R.; Herring, Scott; Hunt, Cynthia; van Dyck, Christopher H.; Carson, Richard E.; MacAvoy, Martha G.; Chertkow, Howard; Bergman, Howard; Hosein, Chris; Black, Sandra; Stefanovic, Bojana; Caldwell, Curtis; Robin Hsiung, Ging-Yuek; Feldman, Howard; Mudge, Benita; Assaly, Michele; Kertesz, Andrew; Rogers, John; Bernick, Charles; Munic, Donna; Kerwin, Diana; Mesulam, Marek-Marsel; Lipowski, Kristine; Wu, Chuang-Kuo; Johnson, Nancy; Sadowsky, Carl; Martinez, Walter; Villena, Teresa; Turner, Raymond Scott; Johnson, Kathleen; Reynolds, Brigid; Sperling, Reisa A.; Johnson, Keith A.; Marshall, Gad; Frey, Meghan; Lane, Barton; Rosen, Allyson; Tinklenberg, Jared; Sabbagh, Marwan N.; Belden, Christine M.; Jacobson, Sandra A.; Sirrel, Sherye A.; Kowall, Neil; Killiany, Ronald; Budson, Andrew E.; Norbash, Alexander; Johnson, Patricia Lynn; Allard, Joanne; Lerner, Alan; Ogrocki, Paula; Hudson, Leon; Fletcher, Evan; Carmichael, Owen; Olichney, John; DeCarli, Charles; Kittur, Smita; Borrie, Michael; Lee, T.-Y.; Bartha, Rob; Johnson, Sterling; Asthana, Sanjay; Carlsson, Cynthia M.; Potkin, Steven G.; Preda, Adrian; Nguyen, Dana; Tariot, Pierre; Reeder, Stephanie; Bates, Vernice; Capote, Horacio; Rainka, Michelle; Scharre, Douglas W.; Kataki, Maria; Adeli, Anahita; Zimmerman, Earl A.; Celmins, Dzintra; Brown, Alice D.; Pearlson, Godfrey D.; Blank, Karen; Anderson, Karen; Santulli, Robert B.; Kitzmiller, Tamar J.; Schwartz, Eben S.; Sink, Kaycee M.; Williamson, Jeff D.; Garg, Pradeep; Watkins, Franklin; Ott, Brian R.; Querfurth, Henry; Tremont, Geoffrey; Salloway, Stephen; Malloy, Paul; Correia, Stephen; Rosen, Howard J.; Miller, Bruce L.; Mintzer, Jacobo; Spicer, Kenneth; Bachman, David; Finger, Elizabether; Pasternak, Stephen; Rachinsky, Irina; Drost, Dick; Pomara, Nunzio; Hernando, Raymundo; Sarrael, Antero; Schultz, Susan K.; Boles Ponto, Laura L.; Shim, Hyungsub; Smith, Karen Elizabeth; Relkin, Norman; Chaing, Gloria; Raudin, Lisa; Smith, Amanda; Fargher, Kristin; Raj, Balebail Ashok; Neylan, Thomas; Grafman, Jordan; Davis, Melissa; Morrison, Rosemary; Hayes, Jacqueline; Finley, Shannon; Friedl, Karl; Fleischman, Debra; Arfanakis, Konstantinos; James, Olga; Massoglia, Dino; Fruehling, J. Jay; Harding, Sandra; Peskind, Elaine R.; Petrie, Eric C.; Li, Gail; Yesavage, Jerome A.; Taylor, Joy L.; Furst, Ansgar J.

    2016-01-01

    There is considerable debate whether Alzheimer's disease (AD) originates in basal forebrain or entorhinal cortex. Here we examined whether longitudinal decreases in basal forebrain and entorhinal cortex grey matter volume were interdependent and sequential. In a large cohort of age-matched older adults ranging from cognitively normal to AD, we demonstrate that basal forebrain volume predicts longitudinal entorhinal degeneration. Models of parallel degeneration or entorhinal origin received negligible support. We then integrated volumetric measures with an amyloid biomarker sensitive to pre-symptomatic AD pathology. Comparison between cognitively matched normal adult subgroups, delineated according to the amyloid biomarker, revealed abnormal degeneration in basal forebrain, but not entorhinal cortex. Abnormal degeneration in both basal forebrain and entorhinal cortex was only observed among prodromal (mildly amnestic) individuals. We provide evidence that basal forebrain pathology precedes and predicts both entorhinal pathology and memory impairment, challenging the widely held belief that AD has a cortical origin. PMID:27811848

  12. A Case of Fulminant Myocarditis With Preceding Repeated Episodes of Congestive Heart Failure

    PubMed Central

    Tada, Yuko; Uto, Kenta; Wada, Hiroshi; Sakakura, Ken-ichi; Suzuki, Jun-ichi; Nishikawa, Toshio; Ako, Junya; Momomura, Shin-ichi

    2013-01-01

    We report a rare case of fulminant myocarditis that was considered to have smoldered for a few months before it finally exteriorized. An 80-year-old man had had two episodes of mild congestive heart failure with preserved ejection function (HFPEF) within 3 months before he was finally admitted for the treatment of rapidly progressive heart failure. Cardiac function deteriorated remarkably on the final admission. Extracorporeal cardiopulmonary support was used because of pump failure and conduction disability, however, the patient died on the 16th day. Endomyocardial biopsy revealed numerous inflammatory infiltrates in myocardium compatible with fulminant myocarditis. However, advanced fibrosis and increased number of B lymphocytes and plasma cells found in the present case were not typical for fulminant myocarditis. Considering several distinctive findings in clinical and laboratory findings together, two preceding HFPEF episodes were highly likely to be associated with myocarditis.

  13. MAP kinase-mediated stress relief that precedes and regulates the timing of transcriptional induction.

    PubMed

    Proft, Markus; Struhl, Kevin

    2004-08-06

    In yeast, hyperosmotic stress causes an immediate dissociation of most proteins from chromatin, presumably because cells are unprepared for, and initially unresponsive to, increased ion concentrations in the nucleus. Osmotic stress activates Hog1 MAP kinase, which phosphorylates at least two proteins located at the plasma membrane, the Nha1 Na+/H+ antiporter and the Tok1 potassium channel. Hog1 phosphorylation stimulates Nha1 activity, and this is crucial for the rapid reassociation of proteins with their target sites in chromatin. This initial response to hyperosmolarity precedes and temporally regulates the activation of stress-response genes that depends on Hog1 phosphorylation of transcription factors in the nucleus. Thus, a single MAP kinase coordinates temporally, spatially, and mechanistically distinct responses to stress, thereby providing very rapid stress relief that facilitates subsequent changes in gene expression that permit long-term adaptation to harsh environmental conditions.

  14. Dropped head syndrome preceding the onset of dementia with Lewy bodies.

    PubMed

    Tanaka, Kanta; Wada, Ikko; Okunomiya, Taro; Shima, Atsushi; Kambe, Daisuke; Shinde, Akiyo; Kageyama, Takashi; Suenaga, Toshihiko

    2014-01-01

    A 67-year-old woman developed dropped head. Her neck was severely flexed, with prominent cervical paraspinal muscles, although no parkinsonism was observed. Brain MRI showed no significant findings. We considered dystonia as the cause of the dropped head and administered trihexyphenidyl, an anticholinergic. After 10 years of follow-up, remarkable psychotic symptoms, including hallucinations regarding insects, appeared. Following the discontinuation of trihexyphenidyl, the psychotic symptoms decreased but still remained. (123)I-N-isopropyl-p-iodoamphetamine single-photon emission computed tomography ((123)I-IMP SPECT) revealed hypoperfusion in the bilateral occipital lobes. We diagnosed the patient with dementia with Lewy bodies (DLB). This case suggests that dropped head syndrome may precede the onset of DLB.

  15. An investigation into the precedents of modern drug treatment in psychiatry.

    PubMed

    Moncrieff, J

    1999-12-01

    This paper examines some of the factors associated with the introduction of a range of new drug treatments into psychiatry in the 1950s and 1960s. The nature of psychiatry in the United Kingdom in preceding decades is examined and a continuous emphasis on biological explanations and treatments of mental disorder is revealed. Physical treatment procedures such as insulin coma therapy and shock treatment received most attention. Older drug treatments, although widely used, excited little interest during this time. The new drug treatments by contrast received much attention and began to be regarded as having specific effects on different mental disorders. It is suggested that a combination of long-standing professional concerns and commercial factors helped to account for the rapid acceptance and employment of the new drugs. In turn, these drugs helped to strenghten the hegemony of the medical approach to mental illness.

  16. Horizontal Gene Transfer of Pectinases from Bacteria Preceded the Diversification of Stick and Leaf Insects

    PubMed Central

    Shelomi, Matan; Danchin, Etienne G. J.; Heckel, David; Wipfler, Benjamin; Bradler, Sven; Zhou, Xin; Pauchet, Yannick

    2016-01-01

    Genes acquired by horizontal transfer are increasingly being found in animal genomes. Understanding their origin and evolution requires knowledge about the phylogenetic relationships from both source and recipient organisms. We used RNASeq data and respective assembled transcript libraries to trace the evolutionary history of polygalacturonase (pectinase) genes in stick insects (Phasmatodea). By mapping the distribution of pectinase genes on a Polyneoptera phylogeny, we identified the transfer of pectinase genes from known phasmatodean gut microbes into the genome of an early euphasmatodean ancestor that took place between 60 and 100 million years ago. This transfer preceded the rapid diversification of the suborder, enabling symbiont-free pectinase production that would increase the insects’ digestive efficiency and reduce dependence on microbes. Bacteria-to-insect gene transfer was thought to be uncommon, however the increasing availability of large-scale genomic data may change this prevailing notion. PMID:27210832

  17. Preceding bronchial cutting for exposure of the pulmonary artery buried in scar tissue after chemoradiotherapy.

    PubMed

    Nomori, Hiroaki; Cong, Yue; Sugimura, Hiroshi

    2017-01-01

    It is often difficult to expose the pulmonary artery buried in a scar tissue, especially in lung cancer patients that responded well to neoadjuvant chemoradiotherapy. Difficulty to access pulmonary artery branches may lead to potentially unnecessary pneumonectomy. To complete lobectomy in such cases, a technique with preceding bronchial cutting for exposure of the pulmonary artery is presented. After dissecting the pulmonary vein, the lobar bronchus is cut from the opposite side of the pulmonary artery with scissors. The back wall of the lobar bronchus is cut using a surgical knife from the luminal face, which can expose the pulmonary artery behind the bronchial stump and then complete lobectomy. Fourteen patients have been treated using the present technique, enabling complete resection by lobectomy (including sleeve lobectomy in 3 patients) without major bleeding. The present procedure can expose pulmonary artery buried in scar tissue, resulting in making the lobectomy safer.

  18. A case of multifocal lupus vulgaris that preceded pulmonary tuberculosis in an immune compromised patient.

    PubMed

    Hamada, Manabu; Urabe, Kazunori; Moroi, Yoichi; Koga, Tetsuya; Takeishi, Masaaki; Fujita, Masaki; Nakanishi, Yoichi; Furue, Masutaka

    2004-02-01

    We describe the rare case of a Japanese male with multifocal lupus vulgaris that preceded asymptomatic pulmonary tuberculosis and adult T-cell leukemia/lymphoma (ATL). He visited our hospital with multiple reddish plaques and erythema of 4-12 months duration. A skin biopsy revealed non-caseating epithelioid granulomas. Mycobacterium tuberculosis was detected by polymerase chain reaction (PCR)-hybridization from a skin biopsy specimen and was also isolated from a culture of the skin biopsy sample. The result of chest roentogenography was compatible with pulmonary tuberculosis. In addition, the diagnosis of ATL was based upon the presence of atypical lymphocytes with convoluted nuclei in his peripheral blood and a positive anti-ATL antibody reaction. Cases of cutaneous tuberculosis presenting with unusual clinical features may be on the increase, accompanying the spread of tuberculosis in immunosuppressed patients, including those with ATL and acquired immunodeficiency syndrome (AIDS).

  19. a Revised Stochastic Optimal Velocity Model Considering the Velocity Gap with a Preceding Vehicle

    NASA Astrophysics Data System (ADS)

    Shigaki, Keizo; Tanimoto, Jun; Hagishima, Aya

    The stochastic optimal velocity (SOV) model, which is a cellular automata model, has been widely used because of its good reproducibility of the fundamental diagram, despite its simplicity. However, it has a drawback: in SOV, a vehicle that is temporarily stopped takes a long time to restart. This study proposes a revised SOV model that suppresses this particular defect; the basic concept of this model is derived from the car-following model, which considers the velocity gap between a particular vehicle and the preceding vehicle. A series of simulations identifies the model parameters and clarifies that the proposed model can reproduce the three traffic phases: free, jam, and even synchronized phases, which cannot be achieved by the conventional SOV model.

  20. Electric Current Precedes Emergence of a Lateral Root in Higher Plants

    PubMed Central

    Hamada, Shingo; Ezaki, Shu; Hayashi, Kenshi; Toko, Kiyoshi; Yamafuji, Kaoru

    1992-01-01

    Stable electrochemical patterns appear spontaneously around roots of higher plants and are closely related to growth. An electric potential pattern accompanied by lateral root emergence was measured along the surface of the primary root of adzuki bean (Phaseolus angularis) over 21 h using a microelectrode manipulated by a newly developed apparatus. The electric potential became lower at the point where a lateral root emerged. This change preceded the emergence of the lateral root by about 10 h. A theory is presented for calculating two-dimensional patterns of electric potential and electric current density around the primary root (and a lateral root) using only data on the one-dimensional electric potential measured near the surface of the primary root. The development of the lateral root inside the primary root is associated with the influx of electric current of about 0.7 μA·cm−2 at the surface. Images Figure 7 PMID:16653036