bluuebunny/crossref_metadata_2025_split huggingface dataset:
Cyclooxygenase-2 Is Involved in S100A2-Mediated Tumor Suppression in Squamous Cell Carcinoma
Authors: Tsai Wan-Chi , Tsai Sen-Tien , Jin Ying-Tai , Wu Li-Wha 
Published: August 2006

Abstract
S100A2 is considered a putative tumor suppressor due to its loss or down-regulation in several cancer types. However, no mechanism has been described for the tumor suppressor role of S100A2. In this study, ectopic expression of S100A2 in the human malignant squamous cell carcinoma cell line KB resulted in a significant inhibition of proliferation, migration, and invasion. Moreover, S100A2 significantly reduced the number of colonies (≥0.5 mm) formed in semisolid agar and decreased tumor growth and burden in nude mice. cDNA microarray analysis was used to compare mRNA expression profiles of vector- and S100A2-expressing isogenic cells. Among the genes deregulated by S100A2, the expression of cyclooxygenase-2 (COX-2) mRNA was significantly suppressed by S100A2 (2.4-fold). Western blot analysis confirmed that S100A2 reduced the expression of COX-2 protein in stably and transiently transfected KB and RPMI-2650 cells. COX-2 is frequently overexpressed in various types of cancer and plays an important role in tumor progression. Partial restoration of COX-2 expression attenuated the antitumor effect of S100A2 both in vitro and in vivo. Although the interplay between S100A2 and COX-2 remains to be clarified, these findings first showed a potent antitumor role of S100A2 in squamous cell carcinoma partly via reduced expression of COX-2. (Mol Cancer Res 2006;4(8):539–47)
Properties of Synergies Arising from a Theory of Optimal Motor Behavior
Authors: Chhabra Manu , Jacobs Robert A. 
Published: August 2006

We consider the properties of motor components, also known as synergies, arising from a computational theory (in the sense of Marr, 1982) of optimal motor behavior. An actor's goals were formalized as cost functions, and the optimal control signals minimizing the cost functions were calculated. Optimal synergies were derived from these optimal control signals using a variant of nonnegative matrix factorization. This was done using two different simulated two-joint arms—an arm controlled directly by torques applied at the joints and an arm in which forces were applied by muscles—and two types of motor tasks—reaching tasks and via-point tasks. Studies of the motor synergies reveal several interesting findings. First, optimal motor actions can be generated by summing a small number of scaled and time-shifted motor synergies, indicating that optimal movements can be planned in a low-dimensional space by using optimal motor synergies as motor primitives or building blocks. Second, some optimal synergies are task independent—they arise regardless of the task context—whereas other synergies are task dependent—they arise in the context of one task but not in the contexts of other tasks. Biological organisms use a combination of task-independent and task-dependent synergies. Our work suggests that this may be an efficient combination for generating optimal motor actions from motor primitives. Third, optimal motor actions can be rapidly acquired by learning new linear combinations of optimal motor synergies. This result provides further evidence that optimal motor synergies are useful motor primitives. Fourth, synergies with similar properties arise regardless if one uses an arm controlled by torques applied at the joints or an arm controlled by muscles, suggesting that synergies, when considered in “movement space,” are more a reflection of task goals and constraints than of fine details of the underlying hardware.
On the Use of Lidar Images of Smoke Plumes to Measure Dispersion Parameters in the Stable Boundary Layer
Authors: Hiscox April L. , Nappo Carmen J. , Miller David R. 
Published: August 2006

Abstract
In this note a methodology is presented for measuring dispersion parameters based on lidar images, which can be used as an efficient way to remotely monitor time variations of plume dispersion parameters. Lidar images of a smoke plume cross section over a forest canopy during nighttime conditions are analyzed to estimate vertical dispersion parameters and vertical meander of the plume centerline in the near field. Dispersion parameters 60 m downwind are found to have a median value of 2.31 m, with values ranging from a minimum of 0.56 m to a maximum of 5.45 m. Measurements of these parameters have not previously been made outside the restraints of a wind tunnel experiment.
Improved Level-3 Oceanic Rainfall Retrieval from Dual-Frequency Spaceborne Radar Altimeter Systems
Authors: Tournadre J. 
Published: August 2006

Abstract
Since the launch of the Ocean Topography Experiment (TOPEX)/Poseidon in 1992, several studies have demonstrated that dual-frequency altimeter measurements cannot only accurately detect rain events but can also be used to infer quantitative values. The main problems with these techniques are the limited time and space sampling of nadir-looking instruments and the uncertainty in the height of the freezing level necessary to infer the surface rain rate from the measured signal attenuation. In addition to radar altimeters, altimetric satellites carry microwave radiometers designed to correct for atmospheric water effects. Using a radiative transfer model and simplified rainy atmospheres, a method of inversion of the microwave brightness temperatures in terms of freezing level is presented. The surface rain rate is then computed from the altimeter attenuation and the radiometer freezing level. The rain climatology is computed for the three altimeters currently in operation using a mixed lognormal distribution. Comparison with the Global Precipitation Climatology Project and Special Sensor Microwave Imager (SSM/I) climatologies shows that the use of freezing level greatly improves the altimeter climatology, which is of the same quality as that of the SSM/I for annual mean. The merging of the three altimeters is investigated. The resulting monthly mean rain rates are comparable to those derived from SSM/I. The high along-track resolution of altimeters also allows the determination of the length of rain events. The mean length is close to the SSM/I footprint size in the Tropics, but at higher latitude 80% of the rain has length scales smaller than 10 km, which might explain the relative underestimation of the mean rain rate by SSM/I.
Sources of Errors in Rainfall Measurements by Polarimetric Radar: Variability of Drop Size Distributions, Observational Noise, and Variation of Relationships between R and Polarimetric Parameters
Authors: Lee Gyu Won 
Published: August 2006

Abstract
Using a set of long-term disdrometric data and of actual radar measurements from the McGill S-band operational polarimetric radar, several sources of errors in rain measurement with polarimetric radar are explored in order to investigate their relative importance and the feasibility of a polarimetric technique for estimating R in the context of the McGill S-band operational radar that performs a full volume scan of 24 plan position indicators (PPIs) every 5 min. The sources of errors considered are the variability of drop size distributions (DSDs), observational noise, and systematic variation of the relationships between R and polarimetric parameters at different climate regimes.
Additional polarimetric parameters dramatically reduce the effect of the DSD variability on rain estimates by radar. The effectiveness of various multiparameter relationships is investigated. The relationships from the literature that are derived from the DSD model and measured DSDs at a different climate regime differ from those derived from the disdrometric dataset herein. An application of these relationships to the Montreal dataset results in a bias (about 10%–20%) and the significant random error resulting from the DSD variability. These errors should be eliminated by using a relationship suitable for the local climate.
Assuming a measurement noise as expected from a slow scanning polarimetric radar [∼1 rotation per minute (rpm)] and a 10-min smoothing, the R − (Zh, ZDR) relationship outperforms the conventional R − Zh because of the combined effect of the DSD variability and measurement errors. In addition, the marginal measurement noise that is required to have the same accuracy of R − Zh and R − (Zh, ZDR) algorithms is obtained as a function of temporal smoothing. The quantified measurement noise of the McGill S-band fast scanning operational radar (∼6 rpm) is significantly larger than that of a slow scanning radar, implying that a temporal averaging of ZDR of 1 h is needed to achieve some gain with R − (Zh, ZDR).
A Chemical Ionization Mass Spectrometer for Ground-Based Measurements of Nitric Acid
Authors: Kita Kazuyuki , Morino Yu , Kondo Yutaka , Komazaki Yuichi , Takegawa Nobuyuki , Miyazaki Yuzo , Hirokawa Jun , Tanaka Shigeru , Thompson Thomas L. , Gao Ru-Shan , Fahey David W. 
Published: August 2006

Abstract
A chemical ionization mass spectrometer (CIMS) instrument has been developed for high-precision measurements of gaseous nitric acid (HNO3) specifically under high- and variable-humidity conditions in the boundary layer. The instrument’s background signals (i.e., signals detected when HNO3-free air is measured), which depend on the humidity and HNO3 concentration of the sample air, are the most important factor affecting the limit of detection (LOD). A new system to provide HNO3-free air without changing both the humidity and the pressure of the sampled air was developed to measure the background level accurately. The detection limit was about 23 parts per trillion by volume (pptv) for 50-s averages. Field tests, including an intercomparison with the diffusion scrubber technique, were carried out at a surface site in Tokyo, Japan, in October 2003 and June 2004. A comparison between the measured concentrations of HNO3 and particulate nitrate indicated that the interference from particulate nitrate was not detectable (i.e., less than about 1%). The intercomparison indicated that the two independent measurements of HNO3 agreed to within the combined uncertainties of these measurements. This result demonstrates that the CIMS instrument developed in this study is capable of measuring HNO3 mixing ratios with the precision, accuracy, and time resolution required for atmospheric science.
In Situ Cloud Sensing with Multiple Scattering Lidar: Design and Validation of an Airborne Sensor
Authors: Evans K. Franklin , O’Connor Darren , Zmarzly Pat , Lawson R. Paul 
Published: August 2006

Abstract
The in situ cloud lidar is designed to measure cloud volumes of millions of cubic meters to overcome the sampling limitations of traditional cloud probes in inhomogeneous clouds. This technique sends laser pulses horizontally from an aircraft inside an optically thick cloud and measures the time series of the multiply scattered light with wide field-of-view detectors viewing upward and downward. The extinction in liquid clouds averaged over tens to hundreds of meters and the distance to cloud boundaries can be retrieved from the signal measured by a single-wavelength in situ lidar. This paper describes the design and operation of an in situ cloud lidar. A laser in the aircraft cabin outputs 532-nm wavelength pulses at 10 Hz, which are sent through beam-expanding optics for eye safety. The upward- and downward-viewing detectors use photomultiplier tubes and operate with either daytime (3° half angle; 0.37-nm solar-blocking filter) or nighttime (30°) optics. Example daytime lidar signals in dense cloud have a dynamic range of 1000 after solar background subtraction. Results from a nighttime flight in marine stratus are analyzed in detail. The variations in the lidar signals with aircraft travel are much smoother for the longer photon travel times, indicating that the later times sample volumes hundreds of meters in size. Extinction retrievals for 25-m-radius volumes have high correlation (R2 = 0.84) with Forward Scattering Spectrometer Probe (FSSP)-derived extinction, while the correlation is relatively low (R2 = 0.40) for 200-m volumes due to cloud inhomogeneity. Lidar retrievals of cloud-base and -top height from inside the cloud are consistent with cloud boundaries obtained from aircraft penetrations on ascents and descents.
Performance Assessment of the World Wide Lightning Location Network (WWLLN), Using the Los Alamos Sferic Array (LASA) as Ground Truth
Authors: Jacobson Abram R. , Holzworth Robert , Harlin Jeremiah , Dowden Richard , Lay Erin 
Published: August 2006

Abstract
The World Wide Lighting Location Network (WWLLN) locates lightning globally, using sparsely distributed very low frequency (VLF) detection stations. Due to WWLLN’s detection at VLF (in this case ∼10 kHz), the lightning signals from strong strokes can propagate up to ∼104 km to WWLLN sensors and still be suitable for triggering a station. A systematic evaluation of the performance of WWLLN is undertaken, using a higher-frequency (0–500 kHz) detection array [the Los Alamos Sferic Array (LASA)] as a ground truth during an entire thunderstorm season in a geographically confined case study in Florida. It is found that (a) WWLLN stroke-detection efficiency rises sharply to several percent as the estimated lightning current amplitude surpasses ∼30 kA; (b) WWLLN spatial accuracy is around 15 km, good enough to resolve convective-storm cells within a larger storm complex; (c) WWLLN is able to detect intracloud and cloud-to-ground discharges with comparable efficiency, as long as the current is comparable; (d) WWLLN detects lightning-producing storms with high efficiency in every 3-h epoch; thus, WWLLN can be useful for locating deep convection for weather forecasting on 3-h update cycles; and (e) WWLLN detects a stroke count in each storm that is weakly proportional to the stroke count detected by LASA. Thus, to the extent that lightning rate can serve as a statistical proxy for rainfall, WWLLN may eventually provide rainfall-proxy data to be assimilated in 3-h forecast update cycles.
Simulated Doppler Velocity Signatures of Evolving Tornado-Like Vortices
Authors: Davies-Jones Robert P. , Wood Vincent T. 
Published: August 2006

Abstract
Exact solutions of the Navier–Stokes or Euler equations of motion and the continuity equation in cylindrical coordinates for 3D, axisymmetric, inviscid, or laminar flows are utilized to represent evolving vortices that roughly model tornado cyclones or misocyclones contracting to tornadoes. These solutions are unsteady versions of the diffusive Burgers–Rott vortex and the inviscid Rankine-combined vortex. They satisfy the free-slip condition at the ground. Different vortices are obtained by choosing different values of the constant eddy viscosity and uniform horizontal convergence while holding the circulation at infinity constant. A simulated Weather Surveillance Radar-1988 Doppler (WSR-88D) is employed to generate time-varying Doppler velocity signatures in uniform reflectivity of these analytical vortices at ranges of 25 and 50 km from the radar. Mean Doppler velocities are determined by computing 3D integrals over effective resolution volumes. Magnitudes of Doppler vortex signatures at different times in the evolution of the stationary vortices are computed for effective beamwidths of 1.02° and 1.39°, which correspond to azimuthal sampling intervals of 0.5° and 1.0°, respectively. Four tornado predictors—rotational velocity, shear, excess rotational kinetic energy, and circulation—are examined.
Results of the simulations show that for smaller effective beamwidths, Doppler vortex signatures are stronger and exceed fixed threshold values of rotational velocity and shear earlier. With finer azimuthal resolution, tornado cyclone, misocyclone, or tornado signatures switch to tornadic vortex signatures later. Circulations of the vortex signatures give good estimates of the circulations of the simulated tornadoes and tornado cyclones with relative insensitivity to range, effective beamwidth, and stage of evolution. High circulation and convergence values of a rotation signature reveal the potential for a tornado earlier than all the other predictors, which increase significantly during tornadogenesis.
Ground Clutter Filtering Dual-Polarized, Staggered PRT Sequences
Authors: Sachidananda M. , Zrnic Dusan S. 
Published: August 2006

Abstract
A procedure to filter the ground clutter from a dual-polarized, staggered pulse repetition time (PRT) sequence and recover the complex spectral coefficients of the weather signal is presented. While magnitude spectra are sufficient for estimation of the spectral moments from staggered PRT sequences, computation of differential phase in dual-polarized radars requires recovery of the complex spectra. Herein a method is given to recover the complex spectral coefficients after the ground clutter is filtered. Under the condition of “narrow” spectra, it is possible to recover the differential phase, ΦDP, and the copolar correlation coefficient, ρhv, accurately, in addition to the differential reflectivity, ZDR. The technique is tested on simulated time series and on actual radar data. The efficacy of the method is demonstrated on plan position indicator (PPI) plots of polarimetric variables.
A Radar Simulator for High-Resolution Nonhydrostatic Models
Authors: Caumont Olivier , Ducrocq Véronique , Delrieu Guy , Gosset Marielle , Pinty Jean-Pierre , Parent du Châtelet Jacques , Andrieu Hervé , Lemaître Yvon , Scialom Georges 
Published: August 2006

Abstract
A full radar simulator for high-resolution (1–5 km) nonhydrostatic models has been developed within the research nonhydrostatic mesoscale atmospheric (Meso-NH) model. This simulator is made up of building blocks, each of which describes a particular physical process (scattering, beam bending, etc.). For each of these blocks, several formulations have been implemented. For instance, the radar simulator offers the possibility to choose among Rayleigh, Rayleigh–Gans, Mie, or T-matrix scattering methods, and beam bending can be derived from an effective earth radius or can depend on the vertical gradient of the refractive index of air. Moreover, the radar simulator is fully consistent with the microphysical parameterizations used by the atmospheric numerical model.
Sensitivity experiments were carried out using different configurations for the simulator. They permitted the specification of an observation operator for assimilation of radar reflectivities by high-resolution nonhydrostatic numerical weather prediction systems, as well as for their validation. A study of the flash flood of 8–9 September 2002 in southeastern France, which was well documented with volumetric data from an S-band radar, serves to illustrate the capabilities of the radar simulator as a validation tool for a mesoscale model.
True Along-Track Scan to Improve Radiation Budget Estimations
Authors: Capderou Michel , Viollier Michel 
Published: August 2006

Abstract
Multiangle approaches for radiance-to-flux conversion require accurate coregistration between the observations from nadir- and oblique-viewing directions. The along-track mode of Earth Radiation Budget (ERB) scanning instruments, such as the Clouds and the Earth’s Radiant Energy System (CERES), provides some multiangular observations with almost the same target observed from nadir, aft, and fore directions. To improve the overlaps of multiangle observations, this study explains how to introduce a yaw steering angle in the along-track scan mode so as to reduce the residual collocations errors. The implementation of this correction to the CERES/Terra along-track mode shows that the distances between the nadir and the oblique (55°) observations are reduced from about 40 to 2 km. Both oblique radiances are shown to be equal with small rms differences: 3.9% (all scenes) and 1.8% (homogeneous scenes), compared, respectively, to 7.0% and 3.5% before the scan adjustment.
Pharmacological utility of melatonin in the treatment of septic shock: experimental and clinical evidence
Authors: Escames Germaine , Acuña-Castroviejo Darío , López Luis Carlos , Tan Dun-xian , Maldonado Maria Dolores , Sánchez-Hidalgo Marina , León Josefa , Reiter Russel J 
Published: August 2006

Abstract
Sepsis is a major cause of mortality in critically ill patients and develops as a result of the host response to infection. In recent years, important advances have been made in understanding the pathophysiology and treatment of sepsis. Mitochondria play a central role in the intracellular events associated with inflammation and septic shock. One of the current hypotheses for the molecular mechanisms of sepsis is that the enhanced nitric oxide (NO) production by mitochondrial nitric oxide synthase (mtNOS) leads to excessive peroxynitrite (ONOO−) production and protein nitration, impairing mitochondrial function. Despite the advances in understanding of its pathophysiology, therapy for septic shock remains largely symptomatic and supportive. Melatonin has well documented protective effects against the symptoms of severe sepsis/shock in both animals and in humans; its use for this condition significantly improves survival. Melatonin administration counteracts mtNOS induction and respiratory chain failure, restores cellular and mitochondrial redox status, and reduces proinflammatory cytokines. Melatonin clearly prevents multiple organ failure, circulatory failure, and mitochondrial damage in experimental sepsis, and reduces lipid peroxidation, indices of inflammation and mortality in septic human newborns. Considering these effects of melatonin and its virtual absence of toxicity, the use of melatonin (along with conventional therapy) to preserve mitochondrial bioenergetics as well as to limit inflammatory responses and oxidative damage should be seriously considered as a treatment option in both septic newborn and adult patients. This review summarizes the data that provides a rationale for using melatonin in septic shock patients.
Permeation of bioactive constituents from Arnica montana preparations through human skin in-vitro
Authors: Tekko I A , Bonner M C , Bowen R D , Williams A C 
Published: August 2006

Abstract
This study investigated and characterised transdermal permeation of bioactive agents from a topically applied Arnica montana tincture. Permeation experiments conducted over 48 h used polydimethylsiloxane (silastic) and human epidermal membranes mounted in Franz-type diffusion cells with a methanol-water (50:50 v/v) receptor fluid. A commercially available tincture of A. montana L. derived from dried Spanish flower heads was a donor solution. Further donor solutions prepared from this stock tincture concentrated the tincture constituents 1, 2 and 10 fold and its sesquiterpene lactones 10 fold. Permeants were assayed using a high-performance liquid chromatography method. Five components permeated through silastic membranes providing peaks with relative retention factors to an internal standard (santonin) of 0.28, 1.18, 1.45, 1.98 and 2.76, respectively. No permeant was detected within 12 h of applying the Arnica tincture onto human epidermal membranes. However, after 12 h, the first two of these components were detected. These were shown by Zimmermann reagent reaction to be sesquiterpene lactones and liquid chromatography/diode array detection/mass spectrometry indicated that these two permeants were 11,13-dihydrohelenalin (DH) analogues (methacrylate and tiglate esters). The same two components were also detected within 3 h of topical application of the 10-fold concentrated tincture and the concentrated sesquiterpene lactone extract.