Siga este enlace para ver otros tipos de publicaciones sobre el tema: Cyclone appareil.
Artículos de revistas sobre el tema "Cyclone appareil"
Crea una cita precisa en los estilos APA, MLA, Chicago, Harvard y otros
Consulte los 50 mejores artículos de revistas para su investigación sobre el tema "Cyclone appareil".
Junto a cada fuente en la lista de referencias hay un botón "Agregar a la bibliografía". Pulsa este botón, y generaremos automáticamente la referencia bibliográfica para la obra elegida en el estilo de cita que necesites: APA, MLA, Harvard, Vancouver, Chicago, etc.
También puede descargar el texto completo de la publicación académica en formato pdf y leer en línea su resumen siempre que esté disponible en los metadatos.
Explore artículos de revistas sobre una amplia variedad de disciplinas y organice su bibliografía correctamente.
1
Condron, Alan, Grant R. Bigg y Ian A. Renfrew. "Polar Mesoscale Cyclones in the Northeast Atlantic: Comparing Climatologies from ERA-40 and Satellite Imagery". Monthly Weather Review 134, n.º 5 (1 de mayo de 2006): 1518–33. http://dx.doi.org/10.1175/mwr3136.1.
Texto completoResumen
Abstract Polar mesoscale cyclones over the subarctic are thought to be an important component of the coupled atmosphere–ocean climate system. However, the relatively small scale of these features presents some concern as to their representation in the meteorological reanalysis datasets that are commonly used to drive ocean models. Here polar mesocyclones are detected in the 40-Year European Centre for Medium-Range Weather Forecasts (ECMWF) Re-Analysis dataset (ERA-40) in mean sea level pressure and 500-hPa geopotential height, using an automated cyclone detection algorithm. The results are compared to polar mesocyclones detected in satellite imagery over the northeast Atlantic, for the period October 1993–September 1995. Similar trends in monthly cyclone numbers and a similar spatial distribution are found. However, there is a bias in the size of cyclones detected in the reanalysis. Up to 80% of cyclones larger than 500 km are detected in MSL pressure, but this hit rate decreases, approximately linearly, to ∼40% for 250-km-scale cyclones and to ∼20% for 100-km-scale cyclones. Consequently a substantial component of the associated air–sea fluxes may be missing from the reanalysis, presenting a serious shortcoming when using such reanalysis data for ocean modeling simulations. Eight maxima in cyclone density are apparent in the mean sea level pressure, clustered around synoptic observing stations in the northeast Atlantic. They are likely spurious, and a result of unidentified shortcomings in the ERA-40 data assimilation procedure.
2
Harper, Bruce A., John D. Holmes, Jeffrey D. Kepert, Luciano B. Mason y Peter J. Vickery. "Comments on “Estimation of Tropical Cyclone Wind Hazard for Darwin: Comparison with Two Other Locations and the Australian Wind-Loading Code”". Journal of Applied Meteorology and Climatology 51, n.º 1 (enero de 2012): 161–71. http://dx.doi.org/10.1175/jamc-d-10-05011.1.
Texto completoResumen
AbstractCook and Nicholls recently argued in this journal that the city of Darwin (Northern Territory), Australia, should be located in wind region D rather than in the current region C in the Australian/New Zealand Standard AS/NZS 1170.2 wind actions standard, in which region D has significantly higher risk. These comments critically examine the methods used by Cook and Nicholls and find serious flaws in them, sufficient to invalidate their conclusions. Specific flaws include 1) invalid assumptions in their analysis method, including that cyclones are assumed to be at the maximum intensity along their entire path across the sampling circle even after they have crossed extensive land areas; 2) a lack of verification that the simulated cyclone tracks are consistent with the known climatological data and in particular that the annual rate of simulated cyclones at each station greatly exceeds the numbers recorded for the entire Australian region; and 3) the apparent omission of key cyclones when comparing the risk at Darwin with two other locations. It is shown here that the number of cyclones that have affected Port Hedland (Western Australia), a site in Australia’s region D, greatly exceeds the number that have influenced Darwin over the same period for any chosen threshold of intensity. Analysis of the recorded gusts from anemometers at Port Hedland and Darwin that is presented here further supports this result. On the basis of this evidence, the authors conclude that Darwin’s tropical cyclone wind risk is adequately described by its current location in region C.
3
Knutson, Thomas R., Joseph J. Sirutis, Ming Zhao, Robert E. Tuleya, Morris Bender, Gabriel A. Vecchi, Gabriele Villarini y Daniel Chavas. "Global Projections of Intense Tropical Cyclone Activity for the Late Twenty-First Century from Dynamical Downscaling of CMIP5/RCP4.5 Scenarios". Journal of Climate 28, n.º 18 (11 de septiembre de 2015): 7203–24. http://dx.doi.org/10.1175/jcli-d-15-0129.1.
Texto completoResumen
Abstract Global projections of intense tropical cyclone activity are derived from the Geophysical Fluid Dynamics Laboratory (GFDL) High Resolution Atmospheric Model (HiRAM; 50-km grid) and the GFDL hurricane model using a two-stage downscaling procedure. First, tropical cyclone genesis is simulated globally using HiRAM. Each storm is then downscaled into the GFDL hurricane model, with horizontal grid spacing near the storm of 6 km, including ocean coupling (e.g., “cold wake” generation). Simulations are performed using observed sea surface temperatures (SSTs) (1980–2008) for a “control run” with 20 repeating seasonal cycles and for a late-twenty-first-century projection using an altered SST seasonal cycle obtained from a phase 5 of CMIP (CMIP5)/representative concentration pathway 4.5 (RCP4.5) multimodel ensemble. In general agreement with most previous studies, projections with this framework indicate fewer tropical cyclones globally in a warmer late-twenty-first-century climate, but also an increase in average cyclone intensity, precipitation rates, and the number and occurrence days of very intense category 4 and 5 storms. While these changes are apparent in the globally averaged tropical cyclone statistics, they are not necessarily present in each individual basin. The interbasin variation of changes in most of the tropical cyclone metrics examined is directly correlated to the variation in magnitude of SST increases between the basins. Finally, the framework is shown to be capable of reproducing both the observed global distribution of outer storm size—albeit with a slight high bias—and its interbasin variability. Projected median size is found to remain nearly constant globally, with increases in most basins offset by decreases in the northwest Pacific.
4
Priestley, Matthew D. K., Duncan Ackerley, Jennifer L. Catto, Kevin I. Hodges, Ruth E. McDonald y Robert W. Lee. "An Overview of the Extratropical Storm Tracks in CMIP6 Historical Simulations". Journal of Climate 33, n.º 15 (1 de agosto de 2020): 6315–43. http://dx.doi.org/10.1175/jcli-d-19-0928.1.
Texto completoResumen
AbstractThe representation of the winter and summer extratropical storm tracks in both hemispheres is evaluated in detail for the available models in phase 6 of the Coupled Model intercomparison Project (CMIP6). The state of the storm tracks from 1979 to 2014 is compared to that in ERA5 using a Lagrangian objective cyclone tracking algorithm. It is found that the main biases present in the previous generation of models (CMIP5) still persist, albeit to a lesser extent. The equatorward bias around the SH is much reduced and there appears to be some improvement in mean biases with the higher-resolution models, such as the zonal tilt of the North Atlantic storm track. Low-resolution models have a tendency to underestimate the frequency of high-intensity cyclones with all models simulating a peak intensity that is too low for cyclones in the SH. Explosively developing cyclones are underestimated across all ocean basins and in both hemispheres. In particular the models struggle to capture the rapid deepening required for these cyclones. For all measures, the CMIP6 models exhibit an overall improvement compared to the previous generation of CMIP5 models. In the NH most improvements can be attributed to increased horizontal resolution, whereas in the SH the impact of resolution is less apparent and any improvements are likely a result of improved model physics.
5
Ritchie, Elizabeth A. y William M. Frank. "Interactions between Simulated Tropical Cyclones and an Environment with a Variable Coriolis Parameter". Monthly Weather Review 135, n.º 5 (1 de mayo de 2007): 1889–905. http://dx.doi.org/10.1175/mwr3359.1.
Texto completoResumen
Abstract Numerical simulations of tropical cyclones are performed to examine the effects of a variable Coriolis parameter on the structure and intensity of hurricanes. The simulations are performed using the nonhydrostatic fifth-generation Pennsylvania State University–National Center for Atmospheric Research Mesoscale Model using a 5-km fine mesh and fully explicit representation of moist processes. When a variable Conolis parameter ( f ) environment is applied to a mature tropical cyclone, a persistent north-northwesterly shear develops over the storm center as a result of an interaction between the primary circulation of the storm and the gradient in absolute vorticity. As a result, the variable-f storm quickly develops a persistent wavenumber-1 asymmetry in its inner-core structure with upward motion and rainfall concentrated on the left side of the shear looking downshear, in agreement with earlier studies. In comparison, the constant-f storm develops weak transient asymmetries in structure that are only partially related to a weak vertical wind shear. As a result, it is found that the tropical cyclone with variable f intensifies slightly more slowly than that with constant f, and reaches a final intensity that is about 5 mb weaker. It is argued that this “beta shear” is not adequately represented in large-scale analyses and so does not figure into calculations of environmental shear. Although the effect of the beta shear on the tropical cyclone intensity seems small by itself, when combined with the environmental shear it can produce a large net shear or it can reduce an environmental shear below the apparent threshold to impact storm intensity. If this result proves to be generally true, then the presence of an additional overlooked beta shear may well explain differences in the response of tropical cyclone intensification to westerly versus easterly shear regimes.
6
Schreck, Carl J. y John Molinari. "Tropical Cyclogenesis Associated with Kelvin Waves and the Madden–Julian Oscillation". Monthly Weather Review 139, n.º 9 (septiembre de 2011): 2723–34. http://dx.doi.org/10.1175/mwr-d-10-05060.1.
Texto completoResumen
The Madden–Julian oscillation (MJO) influences tropical cyclone formation around the globe. Convectively coupled Kelvin waves are often embedded within the MJO, but their role in tropical cyclogenesis remains uncertain. This case study identifies the influences of the MJO and a series of Kelvin waves on the formation of two tropical cyclones. Typhoons Rammasun and Chataan developed in the western North Pacific on 28 June 2002. Two weeks earlier, conditions had been unfavorable for tropical cyclogenesis because of uniform trade easterlies and a lack of organized convection. The easterlies gave way to equatorial westerlies as the convective envelope of the Madden–Julian oscillation moved into the region. A series of three Kelvin waves modulated the development of the westerlies. Cyclonic potential vorticity (PV) developed in a strip between the growing equatorial westerlies and the persistent trade easterlies farther poleward. Rammasun and Chataan emerged from the apparent breakdown of this strip. The cyclonic PV developed in association with diabatic heating from both the MJO and the Kelvin waves. The tropical cyclones also developed during the largest superposition of equatorial westerlies from the MJO and the Kelvin waves. This chain of events suggests that the MJO and the Kelvin waves each played a role in the development of Rammasun and Chataan.
7
Yoshida, Ryuji y Hirohiko Ishikawa. "Environmental Factors Contributing to Tropical Cyclone Genesis over the Western North Pacific". Monthly Weather Review 141, n.º 2 (1 de febrero de 2013): 451–67. http://dx.doi.org/10.1175/mwr-d-11-00309.1.
Texto completoResumen
Abstract The flow environment associated with tropical cyclone genesis (TCG) over the western North Pacific was assessed via categorization into five flow patterns: monsoon shear line (SL), monsoon confluence region (CR), monsoon gyre (GY), easterly wave (EW), and preexisting tropical cyclone (PTC). Using reanalysis data and an objective algorithm, the authors defined “contribution scores” for the five flow patterns. Each score represents the contribution to TCG from each flow pattern, and scores were calculated for 908 TCG cases from 1979 to 2008 (30 yr). Of the major contribution flow patterns, SL accounted for 42% of TCGs, EW for 18%, CR for 16%, PTC for 11%, and GY for 6%. Seasonal variations in the occurrence frequency of these five patterns were clear, but interannual variations were not as apparent. Tropical cyclones often appear to be generated in conditions with multiple flow patterns. Thus, relationships between multiple flow patterns were investigated by comparing contribution scores. The SL and CR patterns were strongly correlated to each other, which can be explained by the monsoon southwesterly that organizes both patterns. The EW pattern tends to be independent of the other flow patterns. The PTC pattern has a relatively high correlation with CR, but does not have a correlation with SL or EW. Thus, the characteristics of flow patterns for the occurrence frequency of TCG are derived for a longer period than in previous studies, and correlations among flow patterns are also investigated.
8
Boyd, Anjali D., Shannon Gowans, David A. Mann y Peter Simard. "Tropical Storm Debby: Soundscape and fish sound production in Tampa Bay and the Gulf of Mexico". PLOS ONE 16, n.º 7 (13 de julio de 2021): e0254614. http://dx.doi.org/10.1371/journal.pone.0254614.
Texto completoResumen
Tropical cyclones have large effects on marine ecosystems through direct (e.g., storm surge) and indirect (e.g., nutrient runoff) effects. Given their intensity, understanding their effects on the marine environment is an important goal for conservation and resource management. In June 2012, Tropical Storm Debby impacted coastal Florida including Tampa Bay. Acoustic recorders were deployed prior to the storm at a shallow water location inside Tampa Bay and a deeper water location in the Gulf of Mexico. Ambient noise levels were significantly higher during the storm, and the highest increases were observed at lower frequencies (≤ 500 Hz). Although the storm did not directly hit the area, mean ambient noise levels were as high as 13.5 dB RMS above levels in non-storm conditions. At both the shallow water and the deep water station, the rate of fish calls showed a variety of patterns over the study period, with some rates decreasing during the storm and others showing no apparent reaction. The rates of fish calls were frequently correlated with storm conditions (storm surge, water temperature), but also with lunar cycle. Reactions to the storm were generally stronger in the inshore station, although fish sounds increased quickly after the storm’s passage. Although this was not a major tropical cyclone nor a direct hit on the area, the storm did appear to elicit a behavioral response from the fish community, and ambient noise levels likely limited the abilities of marine species to use sound for activities such as communication. Given the increases in intensity and rainfall predicted for tropical cyclones due to climate change, further studies of the ecological effects of tropical cyclones are needed.
9
Scoccimarro, Enrico, Pier Giuseppe Fogli, Kevin A. Reed, Silvio Gualdi, Simona Masina y Antonio Navarra. "Tropical Cyclone Interaction with the Ocean: The Role of High-Frequency (Subdaily) Coupled Processes". Journal of Climate 30, n.º 1 (enero de 2017): 145–62. http://dx.doi.org/10.1175/jcli-d-16-0292.1.
Texto completoResumen
Through tropical cyclone (TC) activity the ocean and the atmosphere exchange a large amount of energy. In this work possible improvements introduced by a higher coupling frequency are tested between the two components of a climate model in the representation of TC intensity and TC–ocean feedbacks. The analysis is based on the new Centro Euro-Mediterraneo per I Cambiamenti Climatici Climate Model (CMCC-CM2-VHR), capable of representing realistic TCs up to category-5 storms. A significant role of the negative sea surface temperature (SST) feedback, leading to a weakening of the cyclone intensity, is made apparent by the improved representation of high-frequency coupled processes. The first part of this study demonstrates that a more realistic representation of strong TC count is obtained by coupling atmosphere and ocean components at hourly instead of daily frequency. Coherently, the positive bias of the annually averaged power dissipation index associated with TCs is reduced by one order of magnitude when coupling at the hourly frequency, compared to both forced mode and daily coupling frequency results. The second part of this work shows a case study (a modeled category-5 typhoon) analysis to verify the impact of a more realistic representation of the high-frequency coupling in representing the TC effect on the ocean; the theoretical subsurface warming induced by TCs is well represented when coupling the two components at the higher frequency. This work demonstrates that an increased horizontal resolution of model components is not sufficient to ensure a realistic representation of intense and fast-moving systems, such as tropical and extratropical cyclones, but a concurrent increase in coupling frequency is required.
10
DeLong, Marilyn, Mary Alice Casto, Seoha Min y Gozde Goncu-Berk. "Exploring an Up-cycling Design Process for Apparel Design Education". Fashion Practice 9, n.º 1 (24 de mayo de 2016): 48–68. http://dx.doi.org/10.1080/17569370.2016.1148309.
Texto completo
11
Worobets, Jay T., Emma R. Skolnik y Darren J. Stefanyshyn. "Apparel with Far Infrared Radiation for Decreasing an Athlete's Oxygen Consumption during Submaximal Exercise". Research Journal of Textile and Apparel 19, n.º 3 (1 de agosto de 2015): 52–57. http://dx.doi.org/10.1108/rjta-19-03-2015-b007.
Texto completoResumen
Far infrared radiation (FIR) has been shown to have physiological effects when used as a treatment modality for certain medical conditions. Athletic apparel are currently commercially available that are constructed with fabrics that purportedly emit FIR. If apparel with this technology are capable of inducing positive physiological effects, then there may be important implications when worn by an athlete during exercise. The purpose of this study is to examine whether FIR apparel has an effect on oxygen consumption during exercise at submaximal intensities. Twelve male cyclists have completed submaximal incremental cycling tests. Each subject is tested on 4 separate days, twice while wearing a full body Control garment, and twice while wearing a similar garment made out of FIR fabric. Throughout each cycling test, the volume of oxygen uptake is monitored by using a breathing mask and metabolic analysis cart. At lower cycling intensities, the subjects consume statistically significantly less oxygen when wearing the FIR apparel compared to the Control garment, despite performing the same amount of mechanical work. Additional research is required to determine the implication of this effect for a training or competing athlete; however, the results indicate that this apparel technology does elicit a physiological effect.
12
Gonzalez, Martinez, Tanja Vidakovic-Koch, Rafael Kuwertz, Ulrich Kunz, Thomas Turek y Kai Sundmacher. "The kinetics of the hydrogen chloride oxidation". Journal of the Serbian Chemical Society 78, n.º 12 (2013): 2115–30. http://dx.doi.org/10.2298/jsc131119142g.
Texto completoResumen
Hydrogen chloride (HCl) oxidation has been investigated on technical membrane electrode assemblies in a cyclone flow cell. Influence of Nafion loading, temperature and hydrogen chloride mole fraction in the gas phase has been studied. The apparent kinetic parameters like reaction order with respect to HCl, Tafel slope and activation energy have been determined from polarization data. The apparent kinetic parameters suggest that the recombination of adsorbed Cl intermediate is the rate determining step.
13
Bilham, Roger. "The 1737 Calcutta earthquake and cyclone evaluated". Bulletin of the Seismological Society of America 84, n.º 5 (1 de octubre de 1994): 1650–57. http://dx.doi.org/10.1785/bssa0840051650.
Texto completoResumen
Abstract Catalogs of historically devastating earthquakes (e.g., Dunbar et al., 1992) contain an entry for an earthquake in Calcutta in 1737 that is held responsible for the loss of 300,000 lives, thus rendering it one of the three most disastrous earthquakes in history. Yet, evidence for a severe earthquake is weak, consisting of anonymous reports conveyed to Europe 6 months later by merchant ships returning from Bengal. Official accounts of the disaster submitted to the East India Company headquarters in London list 3000 fatalities and omit mention of an earthquake. If the 11 October 1737 Calcutta earthquake is to remain on lists of catastrophic earthquakes, the following issues need to be resolved: the discrepancy between the 1737 urban population of Calcutta (<20,000) and the number of claimed fatalities, the difficulty in distinguishing between damage from shaking and hurricane force winds and flooding that occurred during the same night, and the contradiction between the number of nocturnal deaths and the apparent earthquake resistance of hatched roof dwellings typical of eighteenth century rural Bengal. It is possible that earthquake damage may have been minimal or nonexistent.
14
Eastin, Matthew D. y M. Christopher Link. "Miniature Supercells in an Offshore Outer Rainband of Hurricane Ivan (2004)". Monthly Weather Review 137, n.º 7 (julio de 2009): 2081–104. http://dx.doi.org/10.1175/2009mwr2753.1.
Texto completoResumen
Airborne Doppler radar observations are used to document the structure of three miniature supercells embedded in an outer rainband of Hurricane Ivan on 15 September 2004. The cells were located more than 100 km offshore, beyond the Doppler range of coastal radars. The combination of large CAPE, large vertical wind shear, and moderate cell-relative helicity with an apparent midlevel dry air intrusion provided an offshore environment supporting rotating storms. Each shallow cell contained a ∼5–7-km-diameter mesocyclonic updraft with midlevel updraft and vorticity maxima that exceeded 6 m s−1 and 0.008 s−1, respectively. Such offshore structures are consistent with miniature supercells observed onshore in association with tropical cyclone tornado outbreaks. The strong updrafts resulted from a combination of kinematic convergence, thermal instability, and shear-induced vertical perturbation pressure gradients. Mesocyclone production largely resulted from the tilting and subsequent stretching of low-level horizontal streamwise vorticity into the vertical by the strong updrafts. Evidence of baroclinic contributions from inflow along cell-generated outflow boundaries was minimal. The miniature supercells persisted for at least 3 h during transit from offshore to onshore. Tornadoes were reported in association with two cells soon after moving onshore. These observations build upon a growing body of evidence suggesting that miniature supercells often develop offshore in the outer rainbands of tropical cyclones.
15
Shen, Bing-Yi, Hai-Bin Liu, Ling Cao y Kai-Rong Qin. "Acute Effects of Different Intensities of Cycling Acute Exercise on Carotid Arterial Apparent Elasticity and Hemodynamic Variables". BioMed Research International 2020 (8 de noviembre de 2020): 1–10. http://dx.doi.org/10.1155/2020/9027560.
Texto completoResumen
Background. Cardiovascular disease (CVD) is closely related to arterial elasticity and hemodynamics. Exercises have been reported to immediately decrease arterial apparent elasticity and regulate hemodynamic variables. However, the relationship between them and exercise intensity remains elusive. The purpose of this study was to determine the acute effects of different intensities of acute cycling exercise on carotid arterial apparent elasticity and hemodynamics. Methods. 32 healthy men (age: 19.4 ± 0.6 years) attended the laboratory on five occasions and completed cycling acute exercise for 20 minutes at five intensities (40%, 50%, 60%, 70%, and 80% heart rate reserve (HRR)). At the right carotid artery, center-line velocity and arterial inner diameter waveforms were examined before and immediately after exercise. Based upon the measured data, the classical hemodynamic theory was used to calculate the apparent elasticity and the local hemodynamic variables. Results. The arterial apparent stiffness and the apparent elastic modulus following acute cycling exercise at 60% to 80% HRR were significantly higher than baseline. The mean center-line velocity accelerated from 50% to 80% HRR, but no intensity of intervention altered mean blood flow. Immediately after intervention, the mean wall shear stress and oscillatory shear index increased. Conclusions. Aerobic cycling intervention, with intensity from 40% to 80% HRR, did not change the brain blood supply. A bout of cycling intervention decreased apparent elasticity, and there was an intensity-dependent effect on apparent elasticity and hemodynamic variables. This study would provide referable data for the further study on the effects of aerobic exercise on arterial hemodynamics and elasticity and underlying physiological mechanisms.
16
Crosbie, Ewan y Yolande Serra. "Intraseasonal Modulation of Synoptic-Scale Disturbances and Tropical Cyclone Genesis in the Eastern North Pacific". Journal of Climate 27, n.º 15 (29 de julio de 2014): 5724–45. http://dx.doi.org/10.1175/jcli-d-13-00399.1.
Texto completoResumen
Abstract The influence of the Madden–Julian oscillation (MJO) on synoptic-scale waves, important precursors to tropical cyclones and tropical cyclogenesis, is investigated using a regional model of the eastern North Pacific basin. Cyclogenesis frequency is evaluated with respect to the MJO using a combination of the regional model and the archive best-track data. The statistics of the regional model compare well to the data and suggest that the MJO predominantly deters cyclogenesis during the suppressed phase rather than enhances it during the active phase when compared to neutral conditions. Synoptic-scale variability of cloudiness and eddy kinetic energy and analysis of vortex track statistics show a consistent enhancement of wave strength during the active phases of the MJO supported by both barotropic energetics and tropospheric moisture availability. Vertical wind shear, of critical importance to cyclone development, also exhibits strong variability associated with the phase of the MJO but, contrary to synoptic activity and moisture, results in unfavorable conditions for cyclogenesis during the active phase of the MJO in the region. The result is for the MJO to enhance cyclogenesis frequency relative to neutral conditions during the early active phase but otherwise to result in suppressed activity. In addition to the basinwide longitudinal structure, the local MJO exhibits a distinct north–south structure not apparent in the global pattern but in agreement with recent studies of tropical eastern North Pacific subseasonal variability.
17
Pearson, A., S. R. Flood Page y S. J. Carter. "The apparent antiquity and broad environmental diversity of triterpenoid cyclase genes". Geochimica et Cosmochimica Acta 70, n.º 18 (agosto de 2006): A477. http://dx.doi.org/10.1016/j.gca.2006.06.1417.
Texto completo
18
Cooney, Golm y Brian A. Lawlor. "Rapid cycling mania post head injury". Irish Journal of Psychological Medicine 12, n.º 4 (diciembre de 1995): 150–51. http://dx.doi.org/10.1017/s0790966700014300.
Texto completoResumen
AbstractA case of post traumatic rapid cycling unipolar mania is described in an individual with no apparent genetic predisposition to an affective disorder. A head injury is proposed as being causative. It is suggested that head injury should be included as a cause of rapid cycling affective disorder.
19
Anand-Srivastava, M. B., P. Vinay, J. Genest y M. Cantin. "Effect of atrial natriuretic factor on adenylate cyclase in various nephron segments". American Journal of Physiology-Renal Physiology 251, n.º 3 (1 de septiembre de 1986): F417—F423. http://dx.doi.org/10.1152/ajprenal.1986.251.3.f417.
Texto completoResumen
The effects of rat synthetic atrial natriuretic factor (ANF) [Arg101, Tyr126] were studied on adenylate cyclase activity in various renal structures such as glomeruli, proximal tubules, loops of Henle, and collecting ducts from dog kidney. ANF inhibited adenylate cyclase activity in glomeruli, loops of Henle, and collecting ducts, but not in proximal tubules, in a concentration-dependent manner. The maximal inhibitions observed were approximately 45% in glomeruli and collecting ducts with an apparent Ki of 10(-10)-10(-9) M and 30% in loops of Henle with an apparent Ki of 10(-11)-5 X 10(-10) M. ANF also inhibited the stimulatory responses of various hormones and forskolin on adenylate cyclase in glomeruli, collecting ducts, and loops of Henle. However, the extent of inhibition varied in the three fractions. In addition, ANF showed an additive effect with the inhibitory response of angiotensin II on adenylate cyclase in glomeruli. These data indicate that ANF receptors coupled to adenylate cyclase are present in glomeruli, loops of Henle, and collecting ducts and not in proximal tubules, and it can be suggested that the inhibition of adenylate cyclase by ANF may be one of the mechanisms through which ANF regulates kidney functions.
20
Plummer, David M., Greg M. McFarquhar, Robert M. Rauber, Brian F. Jewett y David C. Leon. "Structure and Statistical Analysis of the Microphysical Properties of Generating Cells in the Comma Head Region of Continental Winter Cyclones". Journal of the Atmospheric Sciences 71, n.º 11 (29 de octubre de 2014): 4181–203. http://dx.doi.org/10.1175/jas-d-14-0100.1.
Texto completoResumen
Abstract This paper presents analyses of the microphysical structure of cloud-top convective generating cells at temperatures between −10° and −55°C across the comma head of 11 continental cyclones, using data collected by the W-band Wyoming Cloud Radar and in situ instrumentation aboard the National Science Foundation (NSF)/NCAR C-130. A case study of one cyclone is presented, followed by statistical analyses of the entire dataset. Ice particle number concentrations averaged 1.9 times larger inside generating cells compared to outside, and derived ice water contents and median mass diameters averaged 2.2 and 1.1 times larger in cells, respectively. Supercooled water was directly measured at temperatures between −31.4° and −11.1°C, with the median and 95th-percentile liquid water content increasing from ~0.09 to 0.12 g m−3 and 0.14 to 0.28 g m−3 over this temperature range, respectively. Liquid water was present in 26% of observations within cells and 18% of observations between cells over the same temperature range, and it was nearly ubiquitous at temperatures above −16°C. The larger ice particle concentrations in cells are consistent with greater ice production in convective updrafts. The increased mass and diameter of the ice particles demonstrate that generating cells provide environments favorable for enhanced particle growth. The impact of water saturation and supercooled water in the cells was evident, with rapid particle growth by diffusion and sometimes riming apparent, in addition to aggregation. Turbulent mixing lessened the observed differences between cells and surrounding regions, with supercooled water observed within and between cells, similar habits within and between cells, and rimed particles evident even in ice-phase conditions.
21
Yu, Lijun, Shuhui Wu y Zhanhong Ma. "Evaluation of Moist Static Energy in a Simulated Tropical Cyclone". Atmosphere 10, n.º 6 (12 de junio de 2019): 319. http://dx.doi.org/10.3390/atmos10060319.
Texto completoResumen
The characteristics of moist static energy (MSE) and its budget in a simulated tropical cyclone (TC) are examined in this study. Results demonstrate that MSE in a TC system is enhanced as the storm strengthens, primarily because of two mechanisms: upward transfer of surface heat fluxes and subsequent warming of the upper troposphere. An inspection of the interchangeable approximation between MSE and equivalent potential temperature (θe) suggests that although MSE is capable of capturing overall structures of θe, some important features will still be distorted, specifically the low-MSE pool outside the eyewall. In this low-MSE region, from the budget analysis, the discharge of MSE in the boundary layer may even surpass the recharge of MSE from the ocean. Unlike the volume-averaged MSE, the mass-weighted MSE in a fixed volume following the TC shows no apparent increase as the TC intensifies, because the atmosphere becomes continually thinner accompanying the warming of the storm. By calculating a mass-weighted volume MSE budget, the TC system is found to export MSE throughout its lifetime, since the radial outflow overwhelms the radial inflow. Moreover, the more intensified the TC is, the more export of MSE there tends to be. The input of MSE by surface heat fluxes is roughly balanced by the combined effects of radiation and lateral export, wherein a great majority of the imported MSE is reduced by radiation, while the export of MSE from the TC system to the environment accounts for only a small portion.
22
Sun, Lanju, Wei Liu, Ruitao Wu, Yongpeng Cui, Yuan Zhang, Yongxu Du, Shuai Liu, Shuang Liu y Huanlei Wang. "Bio-derived yellow porous TiO2: the lithiation induced activation of an oxygen-vacancy dominated TiO2 lattice evoking a large boost in lithium storage performance". Nanoscale 12, n.º 2 (2020): 746–54. http://dx.doi.org/10.1039/c9nr09042h.
Texto completo
23
Harris, Lucas M., Shian-Jiann Lin y ChiaYing Tu. "High-Resolution Climate Simulations Using GFDL HiRAM with a Stretched Global Grid". Journal of Climate 29, n.º 11 (31 de mayo de 2016): 4293–314. http://dx.doi.org/10.1175/jcli-d-15-0389.1.
Texto completoResumen
Abstract An analytic Schmidt transformation is used to create locally refined global model grids capable of efficient climate simulation with gridcell widths as small as 10 km in the GFDL High-Resolution Atmosphere Model (HiRAM). This method of grid stretching produces a grid that varies very gradually into the region of enhanced resolution without changing the topology of the model grid and does not require radical changes to the solver. AMIP integrations were carried out with two grids stretched to 10-km minimum gridcell width: one centered over East Asia and the western Pacific warm pool, and the other over the continental United States. Robust improvements to orographic precipitation, the diurnal cycle of warm-season continental precipitation, and tropical cyclone maximum intensity were found in the region of enhanced resolution, compared to 25-km uniform-resolution HiRAM. The variations in grid size were not found to create apparent grid artifacts, and in some measures the global-mean climate improved in the stretched-grid simulations. In the enhanced-resolution regions, the number of tropical cyclones was reduced, but the fraction of storms reaching hurricane intensity increased, compared to a uniform-resolution simulation. This behavior was also found in a stretched-grid perpetual-September aquaplanet simulation with 12-km resolution over a part of the tropics. Furthermore, the stretched-grid aquaplanet simulation was also largely free of grid artifacts except for an artificial Walker-type circulation, and simulated an ITCZ in its unrefined region more resembling that of higher-resolution aquaplanet simulations, implying that the unrefined region may also be improved in stretched-grid simulations. The improvements due to stretching are attributable to improved resolution as these stretched-grid simulations were sparingly tuned.
24
Evans, Jenni L. y Mark P. Guishard. "Atlantic Subtropical Storms. Part I: Diagnostic Criteria and Composite Analysis". Monthly Weather Review 137, n.º 7 (julio de 2009): 2065–80. http://dx.doi.org/10.1175/2009mwr2468.1.
Texto completoResumen
Subtropical cyclones (ST) have only recently gained attention as damaging weather systems. A set of criteria for identifying and classifying these systems is introduced here and employed to identify 18 ST cases forming in the 1999–2004 hurricane seasons. To be classified as an ST, these systems must have near-surface gale-force winds and show hybrid structure for more than one diurnal cycle. The 18 ST cases are partitioned into four classes based upon their genesis environments. Genesis over waters with SST in excess of 25°C is observed in almost 80% of warm-season cases, in contrast with only 55% in an ST climatology presented in a companion study. The low-shear magnitude constraint recognized for tropical cyclogenesis is less apparent for ST formation with over 50% forming in the two partitions characterized by shear in excess of 10 m s−1. This relatively high-shear environment corresponds to equatorward intrusion of upper troughs over the relatively warm SST present in the mid–late hurricane season. Anomaly composites confirm that ST genesis is associated with the intrusion of an upper trough in the westerlies into a region of relatively warm SST and weak static stability, with a corresponding reduction in the environmental shear near the time of ST genesis. These conditions correspond well with the conditions for tropical transition identified by Davis and Bosart. Indeed, these systems exhibit a propensity to continue development into a tropical cyclone; 80% eventually became named tropical systems. This result is consistent with a recent ST climatology but had not been widely recognized previously. This raises the possibility that tropical storms evolving from ST may have been overlooked or their tracks truncated in the National Hurricane Center Hurricane Database (HURDAT).
25
Rupp, Thomas, Marc Jubeau, Laurent Lamalle, Jan M. Warnking, Guillaume Y. Millet, Bernard Wuyam, François Esteve, Patrick Levy, Alexandre Krainik y Samuel Verges. "Cerebral Volumetric Changes Induced by Prolonged Hypoxic Exposure and Whole-Body Exercise". Journal of Cerebral Blood Flow & Metabolism 34, n.º 11 (27 de agosto de 2014): 1802–9. http://dx.doi.org/10.1038/jcbfm.2014.148.
Texto completoResumen
The present study assessed the isolated and synergetic effects of hypoxic exposure and prolonged exercise on cerebral volume and subedema and symptoms of acute mountain sickness (AMS). Twelve healthy males performed three semirandomized blinded 11- hour sessions with (1) an inspiratory oxygen fraction (FiO2) of 12% and 4-hour cycling, (2) FiO2 = 21% and 4-hour cycling, and (3) FiO2 = 8.5% to 12% at rest (matching arterial oxygen saturation measured during the first hypoxic session). Volumetric, apparent diffusion coefficient (ADC), and arterial spin labelling 3T magnetic resonance imaging sequences were performed after 30 minutes and 10 hours in each session. Thirty minutes of hypoxia at rest induced a significant increase in white-matter volume (+0.8 ± 1.0% compared with normoxia) that was exacerbated after 10 hours of hypoxia at rest (+1.5 ± 1.1%) or with cycling (+1.6 ± 1.1%). Total brain parenchyma volume increased significantly after 10 hours of hypoxia with cycling only (+1.3 ± 1.1%). Apparent diffusion coefficient was significantly reduced after 10 hours of hypoxia at rest or with cycling. No significant change in cerebral blood flow was observed. These results demonstrate changes in white-matter volume as early as after 30 minutes of hypoxia that worsen after 10 hours, probably due to cytotoxic edema. Exercise accentuates the effect of hypoxia by increasing total brain volume. These changes do not however correlate with AMS symptoms.
26
Kishimoto, Ichiro, F. Kent Hamra y David L. Garbers. "Apparent B-type natriuretic peptide selectivity in the kidney due to differential processing". Canadian Journal of Physiology and Pharmacology 79, n.º 8 (1 de agosto de 2001): 715–22. http://dx.doi.org/10.1139/y01-049.
Texto completoResumen
Two natriuretic peptides, atrial natriuretic peptide (ANP) and B-type natriuretic peptide (BNP), are found principally in the heart. In preliminary experiments with mouse kidney cells or slices, we found mouse BNP1-45 much more potent than ANP1-28 in causing elevations of cGMP (>50-fold). The guanylyl cyclase-A (GC-A) receptor has been suggested to represent the primary means by which both peptides signal. In cultured cells overexpressing GC-A, BNP and ANP were almost equivalent in potency, suggesting that a receptor unique for BNP exists in the kidney. However, in mice lacking the GC-A gene, neither BNP nor ANP significantly elevated cGMP in kidney slices. Phosphoramidon, a neutral endopeptidase inhibitor, shifted the apparent potency of ANP to values equivalent to that of BNP, suggesting these kidney cell/slices rapidly degrade ANP but not BNP. Mass spectroscopic analysis confirmed that ANP is rapidly cleaved at the first cysteine of the disulfide ring, whereas BNP is particularly stable to such cleavage. Other tissues (heart, aorta) failed to significantly degrade ANP or BNP, and therefore the kidney-specific degradation of ANP provides a mechanism for preferential regulation of kidney function by BNP independent of peripheral ANP concentration.Key words: guanylyl cyclase-A, atrial natriuretic peptide, B-type natriuretic peptide, neutral endopeptidase.
27
Carricarte, V. C., G. M. Bianchini, J. P. Muschietti, M. T. Téllez-Iñón, A. Perticari, N. Torres y M. M. Flawiá. "Adenylate cyclase activity in a higher plant, alfalfa (Medicago sativa)". Biochemical Journal 249, n.º 3 (1 de febrero de 1988): 807–11. http://dx.doi.org/10.1042/bj2490807.
Texto completoResumen
An adenylate cyclase activity in Medicago sativa L. (alfalfa) roots was partially characterized. The enzyme activity remains in the supernatant fluid after centrifugation at 105,000 g and shows in crude extracts an apparent Mr of about 84,000. The enzyme is active with Mg2+ and Ca2+ as bivalent cations, and is inhibited by EGTA and by chlorpromazine. Calmodulin from bovine brain or spinach leaves activates this adenylate cyclase.
28
Anand-Srivastava, M. B., J. Gutkowska y M. Cantin. "The presence of atrial-natriuretic-factor receptors of ANF-R2 subtype in rat platelets. Coupling to adenylate cyclase/cyclic AMP signal-transduction system". Biochemical Journal 278, n.º 1 (15 de agosto de 1991): 211–17. http://dx.doi.org/10.1042/bj2780211.
Texto completoResumen
The effect of atrial natriuretic factor (ANF) on adenylate cyclase activity was studied in rat platelet membranes. ANF-(99-126)-, -(101-126)-, -(103-126)- and -(103-123)-peptide inhibited adenylate cyclase activity in a concentration-dependent manner with an order of potency of ANF-(103-123)-peptide greater than ANF-(99-126)-peptide greater than ANF-(101-126)-peptide greater than ANF-(103-126)-peptide. ANF-(103-123)-peptide and ANF-(99-126)-peptide inhibited the enzyme activity by about 50-55%, with an apparent Ki between 0.1 and 0.5 nM, and ANF-(101-126)-peptide inhibited the enzyme activity by about 35%, with an apparent Ki between 1 and 3 nM. On the other hand, ANF-(103-126)-peptide was the least potent and inhibited the adenylate cyclase activity by about 30% (Ki approximately 10 nM). The inhibitory effect of ANF on adenylate cyclase was also dependent on the presence of guanine nucleotides and was attenuated by amiloride and pertussis toxin. The stimulatory effects of various agonists such as N-ethylcarboxamideadenosine, prostaglandin E1, isoprenaline and forskolin on adenylate cyclase were also inhibited by ANF to various extents; however, the stimulations were not completely abolished. In addition, 125I-labelled ANF-(99-126)-peptide bound specifically to rat platelet membranes. The binding of 125I-ANF was competitively inhibited in a concentration-dependent manner by the unlabelled peptides which were used for adenylate cyclase inhibition. ANF-(103-123)-peptide, ANF-(99-126)-peptide and ANF-(101-126)-peptide were almost equipotent [IC50 (median inhibitory concentration) = 0.1-1 nM], and ANF-(103-126)-peptide was the least potent (IC50 approximately 10 nM). Scatchard analysis of the data revealed the presence of a single class of binding sites of high affinity (Kd approximately 120 pM). Affinity cross-linking of 125I-ANF-(99-126)-peptide to its binding sites in rat platelet membranes and analysis by SDS/PAGE followed by autoradiography showed a predominant labelling of a protein band with an apparent Mr of 66,000. These data indicate the presence of only ANF-R2 (low-Mr) receptors in platelets and suggest that these receptors may be coupled to the adenylate cyclase system.
29
Ward, G. E., G. W. Moy y V. D. Vacquier. "Phosphorylation of membrane-bound guanylate cyclase of sea urchin spermatozoa." Journal of Cell Biology 103, n.º 1 (1 de julio de 1986): 95–101. http://dx.doi.org/10.1083/jcb.103.1.95.
Texto completoResumen
When Arbacia punctulata spermatozoa are incubated in seawater containing ammonium hydroxide (pH 8.8), the sperm plasma membrane-bound guanylate cyclase is dephosphorylated, its electrophoretic mobility increases (from an apparent molecular mass of 160 to 150 kD), and its enzymatic activity decreases 3.5-fold. Transfer of these cells into ammonium-free seawater (pH 7.4) results in the rephosphorylation of the cyclase, its reconversion to 160 kD, and recovery of the enzymatic activity lost upon dephosphorylation. This is the first direct demonstration that the activity of membrane-bound guanylate cyclase can be regulated by phosphorylation. A plasma membrane preparation is described that specifically supports the in vitro phosphorylation of the guanylate cyclase. This preparation will be useful in more detailed studies on the relationship between phosphorylation state and enzymatic activity of membrane-bound guanylate cyclase.
30
Garbers, David L. "The guanylyl cyclase receptors". Zygote 8, S1 (diciembre de 1999): S24—S25. http://dx.doi.org/10.1017/s0967199400130114.
Texto completoResumen
In the early 1980s both our group (Hansbrough & Garbers, 1981; Garbers et al., 1982) and that of Norio Suzuki (Suzuki et al., 1981) identified the active material in sea urchin egg conditioned media that could stimulate sperm motility and metabolism. In the sea urchins Hemicentrotus pulcherrimus or Strongylocentrotus purpuratus, the active material was a small peptide that we named speract, and the Suzuki group named this and subsequent peptides SAPs, for sperm activating peptides. Subsequently, both groups identified other peptides (see Suzuki & Yoshino, 1992 for review), one of the most interesting being one named resact, the active material in Arbacia punctulata egg conditioned media. This peptide turned out to be the first animal sperm chemoattractant identified (Ward et al., 1985a). A peptide also turned out to be the active principle that explained previous observations of Ward and Vacquier (Ward et al., 1985b; Suzuki et al., 1984) that egg conditioned media could cause the rapid dephosphorylation of a major membrane protein of spermatozoa. The apparent receptor for resact was later identified as a guanylyl cyclase, establishing a new paradigm for low-molecular-weight second messenger signalling, and the major phosphoprotein regulated by resact was also the receptor itself.
31
Montinaro, A. y H. Strauss. "Sulphur tales from the early Archean world". International Journal of Astrobiology 15, n.º 3 (4 de abril de 2016): 177–85. http://dx.doi.org/10.1017/s1473550415000531.
Texto completoResumen
AbstractSedimentary and magmatic rocks and their distinct sulphur isotopic signatures indicate the sources and processes of sulphur cycling, in particular through the analysis of all four stable sulphur isotopes (32S, 33S, 34S and 36S). Research over the past 15 years has substantially advanced our understanding of sulphur cycling on the early Earth, most notably through the discovery of mass-independently fractionated sulphur isotopic signatures. A strong atmospheric influence on the early Archean global sulphur cycle is apparent, much in contrast to the modern world. Diverse microbially driven sulphur cycling is clearly discernible, but its importance for Earth surface environments remains to be quantified.
32
Watanabe, Y. y K. H. Jakobs. "Forskolin sensitizes human platelet adenylate cyclase to modulation of substrate (MgATP) affinity by hormones". Biochemical Journal 237, n.º 1 (1 de julio de 1986): 273–76. http://dx.doi.org/10.1042/bj2370273.
Texto completoResumen
Stimulation of human platelet adenylate cyclase by the diterpene forskolin is associated with a decrease in the apparent substrate (MgATP) affinity of the enzyme. Addition of the stimulatory hormone prostaglandin E1 not only further increased the Vmax. of the forskolin-stimulated platelet adenylate cyclase but also caused a further increase in the Km value for MgATP, by up to 20-fold compared with basal conditions. On the other hand, the inhibitory hormone adrenaline decreased not only the Vmax. but also the Km value of the platelet adenylate cyclase stimulated by forskolin, with or without prostaglandin E1 present. The data indicate that forskolin sensitizes human platelet adenylate cyclase to modulation of substrate (MgATP) affinity by hormones, but there is no such effect in the absence of the diterpene.
33
Gentry, Megan S. y Gary M. Lackmann. "Sensitivity of Simulated Tropical Cyclone Structure and Intensity to Horizontal Resolution". Monthly Weather Review 138, n.º 3 (1 de marzo de 2010): 688–704. http://dx.doi.org/10.1175/2009mwr2976.1.
Texto completoResumen
Abstract The Weather Research and Forecasting (WRF) model is used to test the sensitivity of simulations of Hurricane Ivan (2004) to changes in horizontal grid spacing for grid lengths from 8 to 1 km. As resolution is increased, minimum central pressure decreases significantly (by 30 hPa from 8- to 1-km grid spacing), although this increase in intensity is not uniform across similar reductions in grid spacing, even when pressure fields are interpolated to a common grid. This implies that the additional strengthening of the simulated tropical cyclone (TC) at higher resolution is not attributable to sampling, but is due to changes in the representation of physical processes important to TC intensity. The most apparent changes in simulated TC structure with resolution occur near a grid length of 4 km. At 4-km grid spacing and below, polygonal eyewall segments appear, suggestive of breaking vortex Rossby waves. With sub-4-km grid lengths, localized, intense updraft cores within the eyewall are numerous and both polygonal and circular eyewall shapes appear regularly. Higher-resolution simulations produce a greater variety of shapes, transitioning more frequently between polygonal and circular eyewalls relative to lower-resolution simulations. It is hypothesized that this is because of the ability to resolve a greater range of wavenumbers in high-resolution simulations. Also, as resolution is increased, a broader range of updraft and downdraft velocities is present in the eyewall. These results suggest that grid spacing of 2 km or less is needed for representation of important physical processes in the TC eyewall. Grid-length and domain size suggestions for operational prediction are provided; for operational prediction, a grid length of 3 km or less is recommended.
34
Prokopchuk, Denis y Oleg Pokrovskiy. "On the Enhanced Accuracy of Kinetic Curve Building in Supercritical Fluid Extraction from Aroma Plants Using a New 3D-Printed Extract Collection Device". Molecules 25, n.º 9 (25 de abril de 2020): 2008. http://dx.doi.org/10.3390/molecules25092008.
Texto completoResumen
Accurate collection of extracted material represents a technical problem in supercritical fluid extraction because trapping should be performed in severe conditions of rapidly moving and freezing expanded fluid. We have developed a simple device for effective sample collection in analytical-scale supercritical fluid extraction. The device consists of a cyclone separator equipped with a spray trap and a heated check valve. The cyclone separator and spray trap are manufactured from a light polymer via 3D printing and are quick-detachable, which encourages its use in applications where mass yield measurements are required. The device was compared to a standard tubing-and-vial approach in the task of building kinetic curves for the extraction from two aroma plants, namely, laurel and rosemary. The new device showed almost two-fold increase in extraction trapping, most probably due to better collection of volatile compounds. A curious effect of the number of mass measurement points per curve on apparent yield was observed. An increase in the number of points led to an increase in yield, probably due to the effect of the static–dynamic extract regime posed by the manner in which the device is used.
35
Schopf, J. William, Anatoliy B. Kudryavtsev, Malcolm R. Walter, Martin J. Van Kranendonk, Kenneth H. Williford, Reinhard Kozdon, John W. Valley, Victor A. Gallardo, Carola Espinoza y David T. Flannery. "Reply to Dvořák et al.: Apparent evolutionary stasis of ancient subseafloor sulfur cycling biocoenoses". Proceedings of the National Academy of Sciences 112, n.º 20 (20 de abril de 2015): E2560. http://dx.doi.org/10.1073/pnas.1503754112.
Texto completo
36
Torruella, M., M. M. Flawiá, C. Eisenschlos, L. Molina y Vedia, C. P. Rubinstein y H. N. Torres. "Trypanosoma cruzi adenylate cyclase activity. Purification and characterization". Biochemical Journal 234, n.º 1 (15 de febrero de 1986): 145–50. http://dx.doi.org/10.1042/bj2340145.
Texto completoResumen
Adenylate cyclase activity associated with Trypanosoma cruzi sedimentable fractions was solubilized by treatment with the non-ionic detergent Lubrol PX and 0.5 M-(NH4)2SO4. The following hydrodynamic and molecular parameters were established for a partially purified enzyme-detergent complex: sedimentation coefficient 6.2 S; Stokes radius 5.65 nm; partial specific volume 0.83 ml/g; Mr 244 000; frictional ratio 1.33. A Mr of about 124 000 was calculated for the detergent-free protein from these parameters. The pI of this enzyme activity was 6.2. A monoclonal antibody to T. cruzi adenylate cyclase was obtained, which inhibited cyclase activities from several lower eukaryotic organisms. The T. cruzi adenylate cyclase was further purified by using this antibody in immunoaffinity chromatographic columns. Fractions obtained after this chromatography showed, on SDS/polyacrylamide-gel electrophoresis, a main polypeptide band with an apparent Mr of about 56 000, which specifically reacted with the monoclonal antibody.
37
Salman, Wagd, Yannick Ney, Muhammad Jawad Nasim, Torsten Bohn y Claus Jacob. "Turning Apparent Waste into New Value: Up-Cycling Strategies Exemplified by Brewer’s Spent Grains (BSG)". Current Nutraceuticals 1, n.º 1 (29 de abril de 2020): 6–13. http://dx.doi.org/10.2174/2665978601666200220100600.
Texto completoResumen
Background: The production, distribution, consumption, and removal of food produces a wide range of organic by-products and, eventually, waste. This kind of waste not only places a considerable burden on the environment and food economy, it also represents an opportunity to harvest additional value, often within an unexpected context and with little connection to the original food item it originates from. Objectives: Brewer’s spent grain (BSG) is such a waste material produced in considerable quantities as a by-product of the beer industry. Although traditionally discarded or fed to animals, it is rich in a wide range of interesting biomolecules and can be converted into a wide spectrum of valuable products. Results: Traditional and more innovative applications of BSG illustrate the concept of up-cycling in the food industry. With the relevant scientific and engineering base in place, BSG can be turned into a range of valuable products such as Brewer’s vinegar, creams, high-fibre bread, grain burgers, bioplastics, and pellets. Conclusion: In the medium term, rather than composting BSG for biogas or feeding it to animals, it may be seen as a valuable raw material to inspire various small- and medium-sized local industries and bedrock of an entire industry.
38
Grossfeld, Gary D., Uzair B. Chaudhary, David M. Reese, Peter R. Carroll y Eric J. Small. "Intermittent androgen deprivation: update of cycling characteristics in patients without clinically apparent metastatic prostate cancer". Urology 58, n.º 2 (agosto de 2001): 240–45. http://dx.doi.org/10.1016/s0090-4295(01)01114-1.
Texto completo
39
Nupenko, Eugenia V., Michail P. Panchenko, Marina G. Starikova, Alexander V. Grishin y Vsevolod A. Tkachuk. "Apparent activation of rabbit lung membrane adenylate cyclase by cytosolic proteins possessing adenylate kinase activity". Biochimica et Biophysica Acta (BBA) - Molecular Cell Research 1091, n.º 2 (enero de 1991): 213–21. http://dx.doi.org/10.1016/0167-4889(91)90064-5.
Texto completo
40
Bielli, Soline, Christelle Barthe, Olivier Bousquet, Pierre Tulet y Joris Pianezze. "The Effect of Atmosphere-Ocean Coupling on the Structure and Intensity of Tropical Cyclone Bejisa in the Southwest Indian Ocean". Atmosphere 12, n.º 6 (27 de mayo de 2021): 688. http://dx.doi.org/10.3390/atmos12060688.
Texto completoResumen
A set of numerical simulations is relied upon to evaluate the impact of air-sea interactions on the behaviour of tropical cyclone (TC) Bejisa (2014), using various configurations of the coupled ocean-atmosphere numerical system Meso-NH-NEMO. Uncoupled (SST constant) as well as 1D (use of a 1D ocean mixed layer) and 3D (full 3D ocean) coupled experiments are conducted to evaluate the impact of the oceanic response and dynamic processes, with emphasis on the simulated structure and intensity of TC Bejisa. Although the three experiments are shown to properly capture the track of the tropical cyclone, the intensity and the spatial distribution of the sea surface cooling show strong differences from one coupled experiment to another. In the 1D experiment, sea surface cooling (∼1 °C) is reduced by a factor 2 with respect to observations and appears restricted to the depth of the ocean mixed layer. Cooling is maximized along the right-hand side of the TC track, in apparent disagreement with satellite-derived sea surface temperature observations. In the 3D experiment, surface cooling of up to 2.5 °C is simulated along the left hand side of the TC track, which shows more consistency with observations both in terms of intensity and spatial structure. In-depth cooling is also shown to extend to a much deeper depth, with a secondary maximum of nearly 1.5 °C simulated near 250 m. With respect to the uncoupled experiment, heat fluxes are reduced from about 20% in both 1D and 3D coupling configurations. The tropical cyclone intensity in terms of occurrence of 10-m TC wind is globally reduced in both cases by about 10%. 3D-coupling tends to asymmetrize winds aloft with little impact on intensity but rather a modification of the secondary circulation, resulting in a slight change in structure.
41
Greiner, C. y K. H. Jakobs. "Guanine nucleotide-independent inhibition of adenylate cyclase by a stimulatory hormone". Biochemical Journal 254, n.º 1 (15 de agosto de 1988): 27–31. http://dx.doi.org/10.1042/bj2540027.
Texto completoResumen
Stimulation of basal adenylate cyclase activity in membranes of neuroblastoma x glioma hybrid cells by prostaglandin E1 (PGE1) is half-maximal and maximal (about 8-fold) at 0.1 and 10 microM respectively. This hormonal effect requires GTP, being maximally effective at 10 microM. However, at the same concentrations that stimulate adenylate cyclase in the presence of GTP, PGE1 inhibited basal adenylate cyclase activity when studied in the absence of GTP, by maximally 60%. A similar dual action of PGE1 was observed with the forskolin-stimulated adenylate cyclase, although the potency of PGE1 in both stimulating and inhibiting adenylate cyclase was increased and the extent of stimulation and inhibition of the enzyme by PGE1 was decreased by the presence of forskolin. The inhibition of forskolin-stimulated adenylate cyclase by PGE1 occurred without apparent lag phase and was reversed by GTP and its analogue guanosine 5′-[gamma-thio]triphosphate at low concentrations. Treatment of neuroblastoma x glioma hybrid cells or membranes with agents known to eliminate the function of the inhibitory GTP-binding protein were without effect on PGE1-induced inhibition of adenylate cyclase. The data suggest that stimulatory hormone agonist, apparently by activating one receptor type, can cause both stimulation and inhibition of adenylate cyclase, and that the final result depends only on the activity state of the stimulatory GTP-binding protein, Gs. Possible mechanisms responsible for the observed adenylate cyclase inhibition by the stimulatory hormone PGE1 are discussed.
42
Bushfield, M., A. Savage, N. J. Morris y M. D. Houslay. "A mnemonical or negative-co-operativity model for the activation of adenylate cyclase by a common G-protein-coupled calcitonin-gene-related neuropeptide (CGRP)/amylin receptor". Biochemical Journal 293, n.º 1 (1 de julio de 1993): 229–36. http://dx.doi.org/10.1042/bj2930229.
Texto completoResumen
Both amylin and calcitonin-gene-related neuropeptide (CGRP) activated adenylate cyclase activity in hepatocyte membranes around 5-fold in a dose-dependent fashion, with EC50 values of 120 +/- 14 and 0.3 +/- 0.14 nM respectively. Whereas amylin exhibited normal activation kinetics (Hill coefficient, h approximately 1), CGRP showed kinetics indicative of either multiple sites/receptor species having different affinities for this ligand or a single receptor species exhibiting apparent negative co-operativity (h approximately 0.21). The CGRP antagonist CGRP-(8-37)-peptide inhibited adenylate cyclase stimulated by EC50 concentrations of either amylin or CGRP. Inhibition by CGRP-(8-37) was selective in that markedly lower concentrations were required to block the action of amylin (IC50 = 3 +/- 1 nM) compared with that of CGRP itself (IC50 = 120 +/- 11 nM). Dose-effect data for inhibition of CGRP action by CGRP-(8-37) showed normal saturation kinetics (h approximately 1), whereas CGRP-(8-37) inhibited amylin-stimulated adenylate cyclase activity in a fashion which was indicative of either multiple sites or apparent negative co-operativity (h approximately 0.24). Observed changes in the kinetics of inhibition by CGRP-(8-37) of CGRP, but not amylin-stimulated adenylate cyclase, at concentrations of agonists below their EC50 values militated against a model of two distinct populations of non-interacting receptors each able to bind both amylin and CGRP. A kinetic model is proposed whereby a single receptor, capable of being activated by both CGRP and amylin, obeys either a mnemonical kinetic mechanism or one of negative co-operativity with respect to CGRP but not to amylin. The relative merits of these two models are discussed together with a proposal suggesting that the activation of adenylate cyclase by various G-protein-linked receptors may be described by a mnemonical model mechanism.
43
Phillips, Briana y Larry O’Neill. "Observational Analysis of Extratropical Cyclone Interactions with Northeast Pacific Sea Surface Temperature Anomalies". Journal of Climate 33, n.º 15 (1 de agosto de 2020): 6745–63. http://dx.doi.org/10.1175/jcli-d-19-0853.1.
Texto completoResumen
AbstractThis study examines the interaction between a northeast Pacific upper-ocean thermal anomaly and individual fall storm events between 2013 and 2016. In 2013, a large upper-ocean thermal anomaly formed in the Gulf of Alaska (GOA) with sea surface temperatures (SST) warmer than 4°C above the climatological norm. Formation of the anomaly was associated with a persistent atmospheric ridge in the GOA that produced a lull in storm activity in the boreal winter of 2013/14. While reduced storm activity was the apparent cause of this SST anomaly, we present cases where extratropical cyclones significantly eroded its mixed layer heat content on synoptic time scales. Case studies during the 4-yr period 2013–16 using satellite and Argo hydrographic observations show that early fall storms produced the largest surface heat fluxes and the greatest cooling of SST. The magnitude of thermal energy transfer from the ocean to the atmosphere during individual storm events was then determined using vertically integrated heat budgets based on Argo temperature profiles and reanalysis surface heat fluxes. Storm-induced surface heat flux anomalies accounted for approximately 50% of the warm anomaly cooling observed by Argo profiles. This rapid heat loss occurred over time scales of approximately 3–5 days. The decay of the warm SST anomaly (SSTa) occurred much more quickly than expected from classic thermal damping by SST-induced turbulent heat fluxes, which may be attributed here at least partly to much shallower mixed layers during early fall. Analysis of the individual surface flux terms indicated that the latent heat flux was the dominant contributor to storm-induced heat exchange across the air–sea interface.
44
Menchaca, Maximo Q. y Dale R. Durran. "Mountain Waves, Downslope Winds, and Low-Level Blocking Forced by a Midlatitude Cyclone Encountering an Isolated Ridge". Journal of the Atmospheric Sciences 74, n.º 2 (1 de febrero de 2017): 617–39. http://dx.doi.org/10.1175/jas-d-16-0092.1.
Texto completoResumen
Abstract The interaction of a midlatitude cyclone with an isolated north–south mountain barrier is examined using numerical simulation. A prototypical cyclone develops from an isolated disturbance in a baroclinically unstable shear flow upstream of the ridge, producing a cold front that interacts strongly with the topography. The structure and evolution of the lee waves launched by the topography are analyzed, including their temporal and their north–south variation along the ridge. Typical mountain wave patterns are generated by a 500-m-high mountain, but these waves often exhibit significant differences from the waves produced in 2D or 3D simulations with steady large-scale-flow structures corresponding to the instantaneous conditions over the mountain in the evolving flow. When the mountain height is 2 km, substantial wave breaking occurs, both at low levels in the lee and in the lower stratosphere. Despite the north–south uniformity of the terrain profile, large north–south variations are apparent in wave structure and downslope winds. In particular, for a 24-h period beginning after the cold front passes the upstream side of the ridge toward the south, strong downslope winds occur only in the northern half of the lee of the ridge. Just prior to this period, the movement of the cold front across the northern lee slopes is complex and accompanied by a burst of strong downslope winds and intense vertical velocities.
45
O'Malley, Yunxia Q., Maher Y. Abdalla, Michael L. McCormick, Krzysztof J. Reszka, Gerene M. Denning y Bradley E. Britigan. "Subcellular localization ofPseudomonaspyocyanin cytotoxicity in human lung epithelial cells". American Journal of Physiology-Lung Cellular and Molecular Physiology 284, n.º 2 (1 de febrero de 2003): L420—L430. http://dx.doi.org/10.1152/ajplung.00316.2002.
Texto completoResumen
The Pseudomonas aeruginosa secretory product pyocyanin damages lung epithelium, likely due to redox cycling of pyocyanin and resultant superoxide and H2O2generation. Subcellular site(s) of pyocyanin redox cycling and toxicity have not been well studied. Therefore, pyocyanin's effects on subcellular parameters in the A549 human type II alveolar epithelial cell line were examined. Confocal and electron microscopy studies suggested mitochondrial redox cycling of pyocyanin and extracellular H2O2release, respectively. Pyocyanin decreased mitochondrial and cytoplasmic aconitase activity, ATP levels, cellular reduction of 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide, and mitochondrial membrane potential. These effects were transient at low pyocyanin concentrations and were linked to apparent cell-mediated metabolism of pyocyanin. Overexpression of MnSOD, but not CuZnSOD or catalase, protected cellular aconitase, but not ATP, from pyocyanin-mediated depletion. This suggests that loss of aconitase activity is not responsible for ATP depletion. How pyocyanin leads to ATP depletion, the mechanism of cellular metabolism of pyocyanin, and the impact of mitochondrial pyocyanin redox cycling on other cellular events are important areas for future study.
46
Kurilenko, Konstantin A., Oleg A. Shlyakhtin, Oleg A. Brylev, Dmitry I. Petukhov y Alexey V. Garshev. "Effect of nanostructured carbon coatings on the electrochemical performance of Li1.4Ni0.5Mn0.5O2+ x -based cathode materials". Beilstein Journal of Nanotechnology 7 (9 de diciembre de 2016): 1960–70. http://dx.doi.org/10.3762/bjnano.7.187.
Texto completoResumen
Nanocomposites of Li1.4Ni0.5Mn0.5O2+ x and amorphous carbon were obtained by the pyrolysis of linear and cross-linked poly(vinyl alcohol) (PVA) in presence of Li1.4Ni0.5Mn0.5O2+ x . In the case of linear PVA, the formation of nanostructured carbon coatings on Li1.4Ni0.5Mn0.5O2+ x particles is observed, while for cross-linked PVA islands of mesoporous carbon are located on the boundaries of Li1.4Ni0.5Mn0.5O2+ x particles. The presence of the carbon framework leads to a decrease of the polarization upon cycling and of the charge transfer resistance and to an increase in the apparent Li+ diffusion coefficient from 10−16 cm2·s−1 (pure Li1.4Ni0.5Mn0.5O2+ x ) to 10−13 cm2·s−1. The nanosized carbon coatings also reduce the deep electrochemical degradation of Li1.4Ni0.5Mn0.5O2+ x during electrochemical cycling. The nanocomposite obtained by the pyrolysis of linear PVA demonstrates higher values of the apparent lithium diffusion coefficient, a higher specific capacity and lower values of charge transfer resistance, which can be related to the more uniform carbon coatings and to the significant content of sp2-hybridized carbon detected by XPS and by Raman spectroscopy.
47
Garcia-Robledo, Emilio, Cory C. Padilla, Montserrat Aldunate, Frank J. Stewart, Osvaldo Ulloa, Aurélien Paulmier, Gerald Gregori y Niels Peter Revsbech. "Cryptic oxygen cycling in anoxic marine zones". Proceedings of the National Academy of Sciences 114, n.º 31 (17 de julio de 2017): 8319–24. http://dx.doi.org/10.1073/pnas.1619844114.
Texto completoResumen
Oxygen availability drives changes in microbial diversity and biogeochemical cycling between the aerobic surface layer and the anaerobic core in nitrite-rich anoxic marine zones (AMZs), which constitute huge oxygen-depleted regions in the tropical oceans. The current paradigm is that primary production and nitrification within the oxic surface layer fuel anaerobic processes in the anoxic core of AMZs, where 30–50% of global marine nitrogen loss takes place. Here we demonstrate that oxygenic photosynthesis in the secondary chlorophyll maximum (SCM) releases significant amounts of O2to the otherwise anoxic environment. The SCM, commonly found within AMZs, was dominated by the picocyanobacteriaProchlorococcusspp. Free O2levels in this layer were, however, undetectable by conventional techniques, reflecting a tight coupling between O2production and consumption by aerobic processes under apparent anoxic conditions. Transcriptomic analysis of the microbial community in the seemingly anoxic SCM revealed the enhanced expression of genes for aerobic processes, such as nitrite oxidation. The rates of gross O2production and carbon fixation in the SCM were found to be similar to those reported for nitrite oxidation, as well as for anaerobic dissimilatory nitrate reduction and sulfate reduction, suggesting a significant effect of local oxygenic photosynthesis on Pacific AMZ biogeochemical cycling.
48
Tremblay, Johanne y Pavel Hamet. "Biochemical mechanisms of atrial natriuretic factor action". Canadian Journal of Physiology and Pharmacology 67, n.º 9 (1 de septiembre de 1989): 1124–29. http://dx.doi.org/10.1139/y89-179.
Texto completoResumen
Since atrial natriuretic factor (ANF) is a natriuretic and vasodilatory hormone, its mechanisms of action expectedly involve so-called negative pathways of cell stimulation, notably cyclic nucleotides. Indeed, the guanylate cyclase–cyclic GMP (cGMP) system appears to be the principal mediator of ANF's action. Specifically, particulate guanylate cyclase, a membrane glycoprotein, transmits ANF's effects, as opposed to the activation of soluble guanylate cyclase by such agents as sodium nitroprusside. The stimulation of particulate guanylate cyclase by ANF manifests several characteristics. One of them is the functional irreversibility of stimulation with its apparent physiological consequences: the extended impact of ANF on diuresis and vasodilation in vivo lasts beyond the duration of increased plasma ANF levels and is accompanied by a prolonged elevation of cGMP. Another characteristic is the parallelism between guanylate cyclase stimulation and increases of cGMP in extracellular fluids. cGMP egression appears to be an active process, yet its physiological implications remain to be uncovered. In heart failure, cGMP continues to reflect augmented ANF levels, suggesting that in this disease, the lack of an ANF effect on sodium excretion is due to a defect distal to cGMP generation. In hypertension, where ANF levels are either normal or slightly elevated, probably secondary to high blood pressure, the ANF responsiveness of the particulate guanylate cyclase–cGMP system, the hypotensive effects, diuresis and natriuresis are exaggerated. The implications of this exaggerated responsiveness of the ANF–cGMP system in the pathophysiology of hypertension and its potential therapeutic connotations remain to be evaluated.Key words: ANF, cGMP, guanylate cyclase, hypertension, heart failure.
49
Haynes, Andrew, Matthew D. Linden, Lauren C. Chasland, Kazunori Nosaka, Andrew Maiorana, Ellen A. Dawson, Lawrence H. Dembo, Louise H. Naylor y Daniel J. Green. "Acute impact of conventional and eccentric cycling on platelet and vascular function in patients with chronic heart failure". Journal of Applied Physiology 122, n.º 6 (1 de junio de 2017): 1418–24. http://dx.doi.org/10.1152/japplphysiol.01057.2016.
Texto completoResumen
Evidence-based guidelines recommend exercise therapy for patients with chronic heart failure (CHF). Such patients have increased atherothrombotic risk. Exercise can transiently increase platelet activation and reactivity and decrease vascular function in healthy participants, although data in CHF are scant. Eccentric (ECC) cycling is a novel exercise modality that may be particularly suited to patients with CHF, but the acute impacts of ECC cycling on platelet and vascular function are currently unknown. Our null hypothesis was that ECC and concentric (CON) cycling, performed at matched external workloads, would not induce changes in platelet or vascular function in patients with CHF. Eleven patients with heart failure with reduced ejection fraction (HFrEF) took part in discrete bouts of ECC and CON cycling. Before and immediately after exercise, vascular function was assessed by measuring diameter and flow-mediated dilation (FMD) of the brachial artery. Platelet function was measured by the flow cytometric determination of glycoprotein IIb/IIIa activation and granule exocytosis in the presence and absence of platelet agonists. ECC cycling increased baseline artery diameter (pre: 4.0 ± 0.8 mm vs. post: 4.2 ± 0.7 mm; P = 0.04) and decreased FMD%. When changes in baseline artery diameter were accounted for, the decrease in FMD post-ECC cycling was no longer significant. No changes were apparent after CON. Neither ECC nor CON cycling resulted in changes to any platelet-function measures (all P > 0.05). These results suggest that both ECC and CON cycling, at a moderate intensity and short duration, can be performed by patients with HFrEF without detrimental impacts on vascular or platelet function. NEW & NOTEWORTHY This is the first evidence to indicate that eccentric (ECC) cycling can be performed relatively safely by patients with chronic heart failure (CHF), as it did not result in impaired vascular or platelet function compared with conventional cycling. This is important, as acute exercise can transiently increase atherothrombotic risk, and ECC cycling is a novel exercise modality that may be particularly suited to patients with CHF.
50
Kuznetsova, L. A., S. A. Plesneva, O. V. Chistiakova, T. S. Sharova y M. N. Pertseva. "Regulation of the adenilate cyclase signal system by peptides of the insulin family, epidermal growth factor, and leptin and its functional disturbances in lymphocytes from patients presenting with type 2 diabetes mellitus". Problems of Endocrinology 57, n.º 4 (15 de agosto de 2011): 32–36. http://dx.doi.org/10.14341/probl201157432-36.
Texto completoResumen
This study showed for the first time the stimulating action of peptides of the insulin family, insulin-like growth factor-1, relaxin, and epidermal growth factor (EGF) on the activity of the adenilate cyclase signal system (ACSS) in lymphocytes from the subjects of the control group. These hormonal effects were enhanced in the presence of guanylimidodiphosphate (GIDP). Moreover, leptin was for the first time shown to increase adenilate cyclase activity in lymphocytes from the control subjects and inhibition of this action by antibodies against leptin receptors. The patients presenting with type 2 diabetes mellitus (DM2) showed the enhanced baseline activity of adenilate cyclase in their lymphocytes whereas its stimulation by the above hormones, both in the presence and absence of GIDP, sharply declined. The influence of leptin on adenilate cyclase activity in patients with DM2 was apparent only at its concentrations above 10–8 M; it was inhibited by antibodies to leptin receptors. The results of this study indicate that disturbances of hormonal stimulation of adenilate cyclase activity in lymphocites of diabetic patients may be due to functional defects located at the receptor level in the case of leptin and at the level of Gs protein and its coupling to adenulate cyclase in case of peptides of the insulin family and GF. These findings confirm the concept being developed by the author according to which molecular defects in the hormone-dependent ACSS system constitute one of the main causes underlying the development of DM2.