bluuebunny/crossref_metadata_2025_split huggingface dataset:
Splenic artery ligation ameliorates hepatic ischemia and reperfusion injury in rats
Authors: Ito Koji , Ozasa Hisashi , Noda Yumi , Horikawa Saburo 
Published: January 2006

Abstract: Background/Aims: Hepatic injury caused by ischemia/reperfusion (I/R) is a key clinical problem associated with liver transplantation and liver surgery. The spleen is involved in hepatic I/R injury. In this study, we examined the effects of splenic artery ligation on hepatic I/R injury.Methods: Splenic artery ligation was performed 7 days, 3 days, or just before the hepatic ischemia. Hepatic ischemia was conducted by occluding the blood vessels to the median and left lateral lobes with an atraumatic vascular clamp. Hepatic I/R injury was induced by 45 min of ischemia followed by 120 min of reperfusion.Results: When splenic artery ligation was performed at 3 days or just before the ischemia, serum aspartate transaminase and alanine transaminase activities, as markers for hepatic injury, decreased as compared with the rats with I/R alone. Splenic artery ligation also reduced the myeloperoxidase activity, an enzyme present in neutrophils, and the expression of interleukin‐6 mRNA, a proinflammatory cytokine, in rat livers with I/R. Efficacy of splenic artery ligation on hepatic I/R injury was also confirmed by histology. On the other hand, when splenic artery ligation was conducted 7 days before the ischemia, efficacy of splenic artery ligation was disappeared.Conclusions: Splenic artery ligation ameliorates hepatic I/R injury in rats. These results strongly suggest the clinical usefulness of this surgical procedure to protect the liver against I/R injury.
Transient‐Outward K+Channel Inhibition Facilitates L‐Type Ca2+Current in Heart
Authors: WANG YANGGAN , CHENG JUN , TANDAN SAMVIT , JIANG MINJIE , McCLOSKEY DIANA T. , HILL JOSEPH A. 
Published: January 2006

Background:Transient outward current (Ito) and L‐type calcium current (ICa) are important repolarization currents in cardiac myocytes. These two currents often undergo disease‐related remodeling while other currents are spared, suggesting a functional coupling between them. Here, we investigated the effects of Itochannel blockers, 4‐aminopyridine (4‐AP) and heteropodatoxin‐2 (HpTx2), on ICain cardiac ventricular myocytes.Methods and Results:ICawas recorded in enzymatically dissociated mouse and guinea pig ventricular myocytes using the whole‐cell voltage clamp method. In mouse ventricular myocytes, 4‐AP (2 mM) significantly facilitated ICaby increasing current amplitude and slowing inactivation. These effects were not voltage‐dependent. Similar facilitating effects were seen when equimolar Ba2+was substituted for external Ca2+, indicating that Ca2+influx is not required. Measurements of Ca2+/calmodulin‐dependent protein kinase (CaMKII) activity revealed significant increases in cells treated with 4‐AP. Pretreatment of cells with 10μM KN93, a specific inhibitor of CaMKII, abolished the effects of 4‐AP on ICa.To test the requirement of Ito, we studied guinea pig ventricular myocytes, which do not express Itochannels. In these cells, 2 mM 4‐AP had no effect on ICaamplitude or kinetics. In both cell types, Ca2+‐induced ICafacilitation, a CaMKII‐dependent process, was observed. However, 4‐AP abolished Ca2+‐induced ICafacilitation exclusively in mouse ventricular myocytes.Conclusion:4‐AP, an Itoblocker, facilitates L‐type Ca2+current through a mechanism involving the Itochannel and CaMKII activation. These data indicate a functional association of ICaand Itoin cardiac myocytes.
Primordial pollution of globular clusters within their host dwarfs embedded in dark matter haloes at high redshifts
Authors: Bekki Kenji 
Published: January 2006

Abstract
Recent observational studies have revealed star-to-star abundance inhomogeneity among light elements (e.g. C, N, O, Na and Al) of stars on the main sequence in the Galactic globular clusters (GCs). One of the promising interpretations for this result is that the observed abundance inhomogeneity is due to the second generation of stars formed from ejecta of the first generation of evolved stars (e.g. asymptotic giant branch stars) within GCs. However, it remains unclear whether and how this primordial pollution can occur within GCs. We here propose a new scenario in which primordial pollution of GCs is highly likely to occur if GCs are located in the central regions of high-redshift dark matter subhaloes that can host low-mass dwarf galaxies. In this scenario, gas ejected from the first generation of stars of GCs can be effectively trapped in the deep gravitational potential of their host haloes, and consequently can be consumed for the formation of the second generation of stars without losing a significant amount of gas by ram pressure stripping of interstellar and intergalactic medium. During merging of these haloes with the proto-Galaxy, the haloes are completely destroyed owing to the strong tidal field of the Galaxy. The self-polluted GCs located initially in the central regions of the haloes can survive tidal destruction owing to their compactness and finally become the Galactic halo GCs. In this scenario, ejecta of field stars surrounding the central GCs can be also converted into stars within their host dwarfs and finally become the second generation of stars of GCs. We also discuss the origin of the difference in the degree of abundance inhomogeneity between different GCs, such as ω Centauri and NGC 6752, in terms of the difference in physical properties between host haloes from which GCs originate.
Condensation temperature trends among stars with planets
Authors: Gonzalez Guillermo 
Published: January 2006

Abstract
Results from detailed spectroscopic analyses of stars hosting massive planets are employed to search for trends between abundances and condensation temperatures. The elements C, S, Na, Mg, Al, Ca, Sc, Ti, V, Cr, Mn, Fe, Ni and Zn are included in the analysis of 64 stars with planets and 33 comparison stars. No significant trends are evident in the data. This null result suggests that accretion of rocky material on to the photospheres of stars with planets is not the primary explanation for their high metallicities. However, the differences between the solar photospheric and meteoritic abundances do display a weak but significant trend with condensation temperature. This suggests that the metallicity of the Sun's envelope has been enriched relative to its interior by about 0.07 dex.
The near-infrared spectrum of Mrk 1239: direct evidence of the dusty torus?
Authors: Rodríguez-Ardila A. , Mazzalay X. 
Published: January 2006

Abstract
We report 0.8–4.5 μm SpeX spectroscopy of the narrow-line Seyfert 1 galaxy Mrk 1239. The spectrum is outstanding because the nuclear continuum emission in the near-infrared (NIR) is dominated by a strong bump of emission peaking at 2.2 μm, with a strength not reported before in an active galactic nucleus. A comparison of the Mrk 1239 spectrum to that of Ark 564 allowed us to conclude that the continuum is strongly reddened by E(B−V) = 0.54. The excess of emission, confirmed by aperture photometry and additional NIR spectroscopy, follows a simple blackbody curve at T∼ 1200 K. This suggests that we may be observing direct evidence of dust heated to near to the sublimation temperature, likely produced by the putative torus of the unification model. Although other alternatives are also plausible, the lack of star formation, the strong polarization and low extinction derived for the emission lines support the scenario where the hot dust is located between the narrow line region and the broad line region.
THE ROLE OF ROOT EXUDATES IN RHIZOSPHERE INTERACTIONS WITH PLANTS AND OTHER ORGANISMS
Authors: Bais Harsh P. , Weir Tiffany L. , Perry Laura G. , Gilroy Simon , Vivanco Jorge M. 
Published: January 2006

The rhizosphere encompasses the millimeters of soil surrounding a plant root where complex biological and ecological processes occur. This review describes recent advances in elucidating the role of root exudates in interactions between plant roots and other plants, microbes, and nematodes present in the rhizosphere. Evidence indicating that root exudates may take part in the signaling events that initiate the execution of these interactions is also presented. Various positive and negative plant-plant and plant-microbe interactions are highlighted and described from the molecular to the ecosystem scale. Furthermore, methodologies to address these interactions under laboratory conditions are presented. [ Addendum ]
Factors Affecting the Evolution of Hurricane Erin (2001) and the Distributions of Hydrometeors: Role of Microphysical Processes
Authors: McFarquhar Greg M. , Zhang Henian , Heymsfield Gerald , Halverson Jeffrey B. , Hood Robbie , Dudhia Jimy , Marks Frank 
Published: January 2006

Abstract
Fine-resolution simulations of Hurricane Erin are conducted using the fifth-generation Pennsylvania State University–NCAR Mesoscale Model (MM5) to investigate roles of thermodynamic, boundary layer, and microphysical processes on Erin’s structure and evolution. Choice of boundary layer scheme has the biggest impact on simulations, with the minimum surface pressure (Pmin) averaged over the last 18 h (when Erin is relatively mature) varying by over 20 hPa. Over the same period, coefficients used to describe graupel fall speeds (Vg) affect Pmin by up to 7 hPa, almost equivalent to the maximum 9-hPa difference between microphysical parameterization schemes; faster Vg and schemes with more hydrometeor categories generally give lower Pmin. Compared to radar reflectivity factor (Z) observed by the NOAA P-3 lower fuselage radar and the NASA ER-2 Doppler radar (EDOP) in Erin, all simulations overpredict the normalized frequency of occurrence of Z larger than 40 dBZ and underpredict that between 20 and 40 dBZ near the surface; simulations overpredict Z larger than 25 to 30 dBZ and underpredict that between 15 and 25 or 30 dBZ near the melting layer, the upper limit depending on altitude. Brightness temperatures (Tb) computed from modeled fields at 37.1- and 85.5-GHz channels that respond to scattering by graupel-size ice show enhanced scattering, mainly due to graupel, compared to observations. Simulated graupel mixing ratios are about 10 times larger than values observed in other hurricanes. For the control run at 6.5 km averaged over the last 18 simulated hours, Doppler velocities computed from modeled fields (Vdop) greater than 5 m s−1 make up 12% of Erin’s simulated area for the base simulation but less than 2% of the observed area. In the eyewall, 5% of model updrafts above 9 km are stronger than 10 m s−1, whereas statistics from other hurricanes show that 5% of updrafts are stronger than only 5 m s−1. Variations in distributions of Z, vertical motion, and graupel mixing ratios between schemes are not sufficient to explain systematic offsets between observations and models. A new iterative condensation scheme, used with the Reisner mixed-phase microphysics scheme, limits unphysical increases of equivalent potential temperature associated with many condensation schemes and reduces the frequency of Z larger than 50 dBZ, but has minimal effect on Z below 50 dBZ, which represent 95% of the modeled hurricane rain area. However, the new scheme changes the Erin simulations in that 95% of the updrafts are weaker than 5 m s−1 and Pmin is up to 12 hPa higher over the last 18 simulated hours.
X-band Polarimetric Radar Rainfall Measurements in Keys Area Microphysics Project
Authors: Anagnostou Emmanouil N. , Grecu Mircea , Anagnostou Marios N. 
Published: January 2006

Abstract
The Keys Area Microphysics Project (KAMP), conducted as part of NASA’s Fourth Convective and Moisture Experiment (CAMEX-4) in the lower Keys area, deployed a number of ground radars and four arrays of rain gauge and disdrometer clusters. Among the various instruments is an X-band dual-polarization Doppler radar on wheels (XPOL), contributed by the University of Connecticut. XPOL was used to retrieve rainfall rate and raindrop size distribution (DSD) parameters to be used in support of KAMP science objectives. This paper presents the XPOL measurements in KAMP and the algorithm developed for attenuation correction and estimation of DSD model parameters. XPOL observations include the horizontal polarization reflectivity ZH, differential reflectivity ZDR, and differential phase shift ΦDP. Here, ZH and ZDR were determined to be positively biased by 3 and 0.3 dB, respectively. A technique was also applied to filter noise and correct for potential phase folding in ΦDP profiles. The XPOL attenuation correction uses parameterizations that relate the path-integrated specific (differential) attenuation along a radar ray to the filtered-ΦDP (specific attenuation) profile. Attenuation-corrected ZH and specific differential phase shift (derived from filtered ΦDP profiles) data are then used to derive two parameters of the normalized gamma DSD model, that is, intercept (Nw) and mean drop diameter (D0). The third parameter (shape parameter μ) is calculated using a constrained μ–Λ relationship derived from the measured raindrop spectra. The XPOL attenuation correction is evaluated using coincidental nonattenuated reflectivity fields from the Key West Weather Surveillance Radar-1988 Doppler (WSR-88D), while the DSD parameter retrievals are statistically assessed using DSD parameters calculated from the measured raindrop spectra. Statistics show that XPOL DSD parameter estimation is consistent with independent observations. XPOL estimates of water content and Nw are also shown to be consistent with corresponding retrievals from matched ER-2 Doppler radar (EDOP) profiling observations from the 19 September airborne campaign. Results shown in this paper strengthen the applicability of X-band dual-polarization high resolution observations in cloud modeling and precipitation remote sensing studies.
Targeting and Data Assimilation Studies during Hurricane Humberto (2001)
Authors: Aberson Sim D. , Etherton Brian J. 
Published: January 2006

Abstract
Two operational synoptic surveillance missions were conducted by the National Oceanic and Atmospheric Administration into Hurricane Humberto (2001). Forecasts from two leading dynamical hurricane track forecast models were improved substantially during the watch and warning period before a projected landfall by the assimilation of the additional dropwindsonde data. Feasibility tests with a barotropic model suggest that further improvements may be obtained by the use of the ensemble transform Kalman filter for assimilating these additional data into the model. This is the first effort to assimilate data into a hurricane model using the ensemble transform Kalman filter.
Rapid Filamentation Zones in Intense Tropical Cyclones
Authors: Rozoff Christopher M. , Schubert Wayne H. , McNoldy Brian D. , Kossin James P. 
Published: January 2006

Abstract
Intense tropical cyclones often possess relatively little convection around their cores. In radar composites, this surrounding region is usually echo-free or contains light stratiform precipitation. While subsidence is typically quite pronounced in this region, it is not the only mechanism suppressing convection. Another possible mechanism leading to weak-echo moats is presented in this paper. The basic idea is that the strain-dominated flow surrounding an intense vortex core creates an unfavorable environment for sustained deep, moist convection. Strain-dominated regions of a tropical cyclone can be distinguished from rotation-dominated regions by the sign of S21 + S22 − ζ2, where S1 = ux − υy and S2 = υx + uy are the rates of strain and ζ = υx − uy is the relative vorticity. Within the radius of maximum tangential wind, the flow tends to be rotation-dominated (ζ2 &gt; S21 + S22), so that coherent structures, such as mesovortices, can survive for long periods of time. Outside the radius of maximum tangential wind, the flow tends to be strain-dominated (S21 + S22 &gt; ζ2), resulting in filaments of anomalous vorticity. In the regions of strain-dominated flow the filamentation time is defined as τfil = 2(S21 + S22 − ζ2)−1/2. In a tropical cyclone, an approximately 30-km-wide annular region can exist just outside the radius of maximum tangential wind, where τfil is less than 30 min and even as small as 5 min. This region is defined as the rapid filamentation zone. Since the time scale for deep moist convective overturning is approximately 30 min, deep convection can be significantly distorted and even suppressed in the rapid filamentation zone. A nondivergent barotropic model illustrates the effects of rapid filamentation zones in category 1–5 hurricanes and demonstrates the evolution of such zones during binary vortex interaction and mesovortex formation from a thin annular ring of enhanced vorticity.
Warm Core Structure of Hurricane Erin Diagnosed from High Altitude Dropsondes during CAMEX-4
Authors: Halverson J. B. , Simpson J. , Heymsfield G. , Pierce H. , Hock T. , Ritchie L. 
Published: January 2006

Abstract
A combination of multiaircraft and several satellite sensors were used to examine the core of Hurricane Erin on 10 September 2001, as part of the Fourth Convection and Moisture Experiment (CAMEX-4) program. During the first set of aircraft passes, around 1700 UTC, Erin was still at its maximum intensity with a central pressure of 969 hPa and wind speed of 105 kt (54 m s−1).
The storm was moving slowly northwestward at 4 m s−1, over an increasingly colder sea surface. Three instrumented aircraft, the National Oceanic and Atmospheric Administration (NOAA) P3 with radar, the National Aeronautics and Space Administration (NASA) ER-2 at 19 km, newly equipped with GPS dropwindsondes, and the NASA DC-8 with dropwindsondes flew in formation across the eye at about 1700 UTC and again 2.5 h later around 1930 UTC. The storm had weakened by 13 m s−1 between the first and second eye penetrations. The warm core had a maximum temperature anomaly of only 11°C, located at 500 hPa, much weaker and lower than active hurricanes. The core appeared to slant rearward above 400 hPa. Even on the first penetration, airborne radar showed that the eyewall cloud towers were dying. The tops fell short of reaching 15 km and a melting band was found throughout. The tropopause had a bulge to 15.8-km elevation (environment ∼14.4 km) above the dying convection.
The paper presents a consistent picture of the vortex in shear interaction from a primarily thermodynamic perspective. A feature of Erin at this time was a pronounced wavenumber-1 convective asymmetry with all convective activity being confined to the forward quadrants on the left side of the shear vector as calculated from analyses. This is similar to that predicted by the mesoscale numerical models, which also predict that such small amounts of shear would not affect the storm intensity. In Erin, it is remarkable that relatively small shear produced such a pronounced asymmetry in the convection. From the three-dimensional analysis of dropsonde data, horizontal asymmetries in lower and middle tropospheric warming were identified. The warm anomalies are consistent with the pattern of mesoscale vertical motions inferred from the shear-induced wavenumber-1 asymmetry, dipole in rain intensity, and surface convergence.
Ice Microphysics Observations in Hurricane Humberto: Comparison with Non-Hurricane-Generated Ice Cloud Layers
Authors: Heymsfield Andrew J. , Bansemer Aaron , Durden Stephen L. , Herman Robert L. , Bui T. Paul 
Published: January 2006

Abstract
Measurements are presented that were acquired from the National Aeronautics and Space Administration (NASA) DC-8 aircraft during an intensive 3-day study of Tropical Storm/Hurricane Humberto on 22, 23, and 24 September 2001. Particle size distributions, particle image information, vertical velocities, and single- and dual-wavelength Doppler radar observations were obtained during repeated sampling of the eyewall and outer eye regions. Eyewall sampling temperatures ranged from −22° to −57°C and peak updraft velocities from 4 to 15 m s−1.
High concentrations of small ice particles, in the order 50 cm−3 and above, were observed within and around the updrafts. Aggregates, some larger than 7 mm, dominated the larger sizes. The slope of the fitted exponential size distributions λ was distinctly different close to the eye than outside of that region. Even at low temperatures, λ was characteristic of warm temperature growth (λ &lt; 30 cm−1) close to the eye and characteristic of low temperature growth outside of it as well (λ &gt; 100 cm−1).
The two modes found for λ are shown to be consistent with observations from nonhurricane ice cloud layers formed through deep convection, but differ markedly from ice cloud layers generated in situ. It is shown that the median, mass-weighted, terminal velocities derived for the Humberto data and from the other datasets are primarily a function of λ.
Microphysical measurements and dual wavelength radar observations are used together to infer and interpret particle growth processes. Rain in the lower portions of the eyewall extended up to the 6- or 7-km level. In the outer eye regions, aggregation progressed downward from between 8.5 and 11.9 km to the melting layer, with some graupel noted in rainbands. Homogeneous ice nucleation is implicated in the high concentrations of small ice particles observed in the vicinity of the updrafts.
Validation of Rain-Rate Estimation in Hurricanes from the Stepped Frequency Microwave Radiometer: Algorithm Correction and Error Analysis
Authors: Jiang Haiyan , Black Peter G. , Zipser Edward J. , Marks Frank D. , Uhlhorn Eric W. 
Published: January 2006

Abstract
Simultaneous observations by the lower fuselage (LF) radar, the tail (TA) radar, and the Stepped Frequency Microwave Radiometer (SFMR) on board the NOAA WP-3D aircraft are used to validate the rainfall rate estimates from microwave emission measurements of SFMR in tropical cyclones. Data collected in Hurricane Bonnie (1998) and Hurricane Humberto (2001) with a total of 820 paired samples are used in the comparisons. The SFMR 10-s path-integrated rain rates are found to have an overestimate in light rain and an underestimate in heavy rain relative to radar rainfall estimates. Examination of the existing SFMR algorithm shows that the coefficient should be changed in the attenuation—rain-rate relationship used in the inversion algorithm. After this correction, a linear regression result with a correlation coefficient of 0.8 and a slope close to 1 is obtained. But an overall high bias of 5 mm h−1 of the SFMR rainfall estimate relative to radar is also found. The error analysis shows that the bias is nearly independent of rain type, a result confirming Jorgensen and Willis’s conclusion that the drop size distributions between convective and stratiform rain in hurricanes are similar. It is also shown that the bias is a weak function of wind speed, as well as a weak inverse function of radial distance to the hurricane center. Temperature dependence has been ruled out as the main explanation. After doing sensitivity tests, the authors conclude that the bias results from a combination of two factors: an underestimate of the freezing-level height, and a downward increase of radar reflectivity in the high wind regions. If the true downward increase is 1–2 dBZ km−1, a 0.5-km underestimate of the freezing-level height could account for up to a 3–5 mm h−1 bias.