bluuebunny/crossref_metadata_2025 huggingface dataset:
QCD
Authors: FLEMING SEAN
Published: August 2005

In this talk I review recent experimental and theoretical results in QCD. Since the topic is too vast to cover within given time constraints I choose to highlight some of the subjects that I find particularly exciting. On the experimental side I focus on measurements made at the Tevatron. Specifically jet production rates, and the cross section for B meson production. In addition I discuss an interesting measurement made by the Belle collaboration of double exclusive charmonium production. On the theory side I quickly review recent advances in computing hadronic cross sections at subleading order in perturbation theory. I then move on to soft-collinear effective theory. After a lightning review of the formalism I discuss recently published results on color-suppressed B → D decays.
SEARCHES FOR NEW PHYSICS
Authors: BROOIJMANS GUSTAAF
Published: August 2005

Current experimental limits for new physics beyond the Standard Model and hints for deviations from Standard Model expectations will be reviewed, highlighting recent results. Possible signals that will be discussed include Higgs bosons, supersymmetric particles, large extra dimensions, new gauge bosons, dynamical symmetry breaking, muon g - 2, rare decays and lepton flavor violation. The discovery potential of the LHC and ILC will be presented, and the impact of discovery on answering fundamental questions of physics will be assessed.
Results from HARP
Authors:   for the HARP Collaboration., Ellis Malcolm
Published: August 2005

The HARP experiment at CERN is performing extensive measurements of hadron production cross sections and secondary particle yields in the energy range 1.5-15 GeV over the full solid angle, using a large set of cryogenic and solid targets. The hadron production in this region is a relevant ingredient in several branches of neutrino physics, including the characterization of neutrino beams, precise prediction of atmospheric neutrino fluxes, and quantification of pion production and capture for neutrino factory design. An overall precision of a few percent is required from the experiment to reach the final aim. The experimental layout comprises two spectrometers to perform momentum measurement of the secondaries produced in the target. The track momentum reconstruction in the spectrometers is complemented by a set of particle identification detectors that allow, with some redundancy, the particle type discrimination. Approximately 30 TB of data corresponding to 420 millions of events have been collected. The measurements of hadron production cross sections in the forward region (up to about 250 mrad) are reported using the K2K replica targets and a proton beam of 12.9 GeV/c. This is an appealing physics case given the immediate interest for those experiments and for the neutrino community.
The Design and Performance of the MINERνA Detector
Authors: Budd Howard
Published: August 2005

The MINERνA experiment is designed to make precision measurements of various neutrino cross sections in the low energy regime. We describe the detector and give the performance of some of the measured quantities.
Neutrino and Dark matter detection with CLEAN: Preliminary studies
Authors: Nikkel James A. , Lippincott Walter H. , McKinsey Daniel N.
Published: August 2005

CLEAN is an approach to the detection of weakly interacting particles of astrophysical significance, combining large mass and low energy threshold. Preliminary measurements have been made of the time response of the scintillation light due to β energy deposition. We have measured two distinct time constants corresponding to the singlet and triplet states of liquid neon.
Leptogenesis and Neutrino Physics
Authors: PASCOLI SILVIA
Published: August 2005

We review the possible connection between the CP-violating phases which appear in the lepton unitary mixing matrix with the ones which play a role in the leptogenesis mechanism.
MASSIVE ELEMENTARY PARTICLES AND BLACK HOLE PHYSICS IN RESUMMED QUANTUM GRAVITY
Authors: WARD B. F. L.
Published: August 2005

We use exact results in a new approach to quantum gravity to discuss some issues in black hole physics.
APPLICATION OF FLUID MECHANICS TO DARK MATTER
Authors: PAN HONGJUN
Published: August 2005

A dark matter field fluid model is proposed. This model assumes that interstellar space is uniformly filled with dark matter, which possesses a fluid property and a field property; the fluid property follows general fluid mechanics, the interaction of the field with an ordinary baryonic object is proportional to the mass of the object, it also has a force opposing gravity. The data of the Moon-Earth gravitational system agrees with this model very well and the average dark matter field fluid constant is 4.39 × 10-22s-1m-(1-n). This is the first proof that the motion of celestial objects can be treated in a fluid medium. The cosmological redshift formula derived from this model describes the observed redshifts very well. A huge redshift from a distant celestial object may not necessarily indicate that it is quickly receding from us. The universe may not expand as rapidly as thought.
Fitting the HiRes Spectra and Monocular Composition
Authors:   presented on behalf of the High Resolution Fly's Eye Collaboration., Bergman Douglas R.
Published: August 2005

In the first section, we discuss our fits to the latest HiRes monocular spectra. We find that the best fit for the extragalactic component has a spectral index of γ = -2.38±0.04 with a distribution of sources varying with a evolution parameter m = 2.8 ± 0.3. In the second section, we discuss preliminary results from a new composition measurement using HiRes monocular data. We find a predominantly light spectrum above 1017.6 eV.
MEASUREMENT OF THE TOP QUARK PAIR PRODUCTION CROSS SECTION IN LEPTON+JETS FINAL STATES AT DØ USING A MULTIVARIATE TECHNIQUE
Authors:   on behalf of the DØ Collaboration., GOLLING TOBIAS
Published: August 2005

A measurement of the [Formula: see text] production cross-section at [Formula: see text] with the DØ detector at the Fermilab Tevatron, based on the application of a multivariate topological method is presented. The integrated luminosity corresponds to 143.9 pb-1 in the μ+jets and 141.2 pb-1 in the e+jets channel. The preliminary cross-section is measured to be [Formula: see text].
Measurements of the $t{\bar t}$ production cross section at the Tevatron Run II CDF experiment using b-tagging
Authors: Bachacou Henri
Published: August 2005

We present measurements of the [Formula: see text] production cross section in b-tagged lepton + jets events from [Formula: see text] collisions at 1.96 TeV using the CDF detector at Fermilab. B-jets are tagged with either a secondary vertex algorithm, or a soft lepton tagger that identifies muons from B hadron semileptonic decays. With Tevatron Run II data, we estimate the [Formula: see text] signal fraction in two different ways: by estimating the various background contributions, and by fitting directly the leading jet transverse energy spectrum for the signal and background contributions. A subset of the sample, with two secondary vertex tagged jets, yields a production cross section consistent with the inclusive measurements. Results are consistent with a Standard Model [Formula: see text] signal and current measurements of the top quark mass.
Search for Production of Single Top Quarks in the Electron+Jets Channel at DØ
Authors:   For the DØ Collaboration., Jain Supriya
Published: August 2005

We present a search for the electroweak production of single top quarks using 156-169 pb-1 of electron+jets data collected by the DØ detector, at [Formula: see text], at the Tevatron proton-antiproton collider at Fermilab. In the absence of any significant evidence for single top production we set upper limits on the cross section at 95% C.L., of 14 pb for s-channel, 20 pb for t-channel, and 18 pb for the combined s + t channel.
MEASUREMENT OF B(t→Wb)/B(t→Wq)
Authors: TECCHIO MONICA
Published: August 2005

We measure the ratio R = B(t→Wb)/B(t→Wq) in top-quark decays at CDF. R is determined from the relative rates of identified b jets in [Formula: see text] decays reconstructed both in the lepton-plus-jets and dilepton final states. We obtain R>0.62 at the 95% CL, consistent with Standard Model expectations.
ON THE LINEAR FILTERS FOR POINT SOURCE EXTRACTION OF THE PLANCK MISSION
Authors: CHIANG LUNG-YIH , NASELSKY PAVEL D. , NOVIKOV IGOR D.
Published: August 2005

The manifestation of point sources in the upcoming Planck maps is a direct reflection of the properties of the pixelized antenna beam shape for each frequency, which is related to the scan strategy, pointing accuracy, noise properties and map-making algorithm. In this paper we firstly compare analytically two filters for the Planck point source extraction, namely, the adaptive top-hat filter (ATHF) and the theoretically-optimal filter (TOF). Our analyses are based on the premise that the required experiment parameters of the TOF are assumed to be already known: the CMB and noise power spectrum and a circular Gaussian beam shape and size. Whereas, the ATHF does not need any a priori knowledge. The analyses show that the TOF is optimal in terms of the gain after the parameter inputs. We simulate the Planck HFI 100 GHz channel with elliptical beam in rotation to test the efficiency of the TOF and the ATHF. We also apply the ATHF on the WMAP Q-band map and the derived map (the foreground-cleaned map by Tegmark, de Oliveira Costa & Hamilton) from the WMAP one-year data. The uncertainties on the angular power spectrum will hamper the efficiency of the TOF. The ATHF is computationally efficient in tackling more realistic data such as the following effects: an elliptical beam with slow precession and the change of the beam ellipticity ratio due to possible mirror degradation. The ATHF is well suited for the construction of the Planck Early Release Compact Source Catalogue.
ON THE ELECTROMAGNETIC WAVES PROPAGATION IN THE ISOTROPIC UNIVERSE
Authors: MONTANI GIOVANNI , CHERUBINI CHRISTIAN
Published: August 2005

We present a critical analysis concerning the electromagnetic waves propagation on a curved space–time and the correct applicability of the equivalence principle to this phenomenon. In particular we discuss this phenomenon with respect to the Universe background, by showing how any physical wavelength (indeed only those much less than the radius of curvature) could, in principle, freely propagate arbitrarily close to the initial Big-Bang. It is followed by a discussion on the real meaning of the horizons paradox solution, based on extending the result of the classical analysis to the wavelengths of photons present in the primordial thermal bath.
FOREGROUND ANALYSIS FROM THE 1-YEAR WILKINSON MICROWAVE ANISOTROPY PROBE (WMAP) DATA
Authors: NASELSKY PAVEL D. , CHIANG LUNG-YIH , NOVIKOV IGOR D. , VERKHODANOV OLEG V.
Published: August 2005

We present a detailed analysis on the phases of the WMAP foregrounds (synchrotron, free–free and dust emission) of the WMAP K–W bands in order to estimate the significance of the variation of the spectral indices at different components. We first extract the spectral-index varying signals by assuming that the invariant part among different frequency bands have 100% cross-correlation of phases. We then use the minimization of variance, which is normally used for extracting the CMB signals, to extract the frequency independent signals. Such a common signal in each foreground component could play a significant role for any kind of component separation methods, because the methods cannot discriminate frequency independent foregrounds and CMB.
Volumetric matrix strain related to intraformational faulting in argillaceous sediments
Authors: Dehandschutter B. , Gaviglio P. , Sizun J. P. , Sintubin M. , Vandycke S. , Vandenberghe N. , Wouters L.
Published: August 2005

Soft-sediment deformation involves complex interactions between discrete fracturing and diffuse bulk strain, described in terms of volume change and shear strain in a critical state mechanics framework. This study reports on a mesoscale normal fault zone, intraformational in Oligocene argillaceous sediments from the Boom Formation (Belgium), containing several metre-scale normal fault strands. They form either discrete fault planes or decimetre-wide shear zones with internal fabric. The faults have been subjected to microtectonic and petrophysical analysis. Small but significant changes occur in the porous network of the argillaceous matrix approaching a fault or shear zone, indicating compactional strain in both footwall and hanging wall. Internal compaction associated with faulting is put forward as a ductile–brittle feedback mechanism in the kinematics of intraformational fracture systems. Small differential stress induced by compaction and minor regional tectonic forces (differential uplift and tilt) and subsequent gravitational forces (downslope shear stress) induce small shear bands in nearly critically stressed weak mud. Shear banding is accompanied by layer-parallel shortening and bulk volume loss. This provides an additional extension of endogenous origin, accommodated by further deformation. This ductile–brittle feedback mechanism eventually leads to commonly observed intraformational collapse structures called polygonal fault systems.
Integrated petrographic and geochemical record of hydrocarbon seepage on the Vøring Plateau
Authors: Mazzini A. , Aloisi G. , Akhmanov G. G. , Parnell J. , Cronin B. T. , Murphy P.
Published: August 2005

Authigenic carbonate crusts, nodules and chemoherms were sampled from pockmarks and mud diapirs on the southern part of the Vøring Plateau during the TTR-8 and TTR-10 marine expeditions. A petrographic and geochemical study was carried out to investigate their possible relationship with the seepage of hydrocarbon fluids. All authigenic carbonates are depleted in
13
C (−31.6‰ <
δ
13
C < −52‰) indicating that methane is the primary source of the carbonate carbon. Furthermore, pyrite framboids are often associated with these samples, indicating that sulphate reduction is spatially coupled with methane oxidation and implying that the carbonates are formed through the anaerobic oxidation of methane. The oxygen stable isotope composition of the near-subsurface carbonates (3.1‰ <
δ
18
O < 4.9‰) suggests a precipitation temperature very close to the one recorded on the sea floor (between −1 and 2 °C), which is consistent with their stratigraphic position, and a recent (Holocene?) age of formation. Carbonates sampled from greater depths (up to 5.5 m below the sea floor) are richer in
18
O (4.6‰ <
δ
18
O < 6.2‰), which is interpreted as a result of precipitation from an
18
O-rich fluid. The occurrence of different carbonate mineral phases (aragonite, calcite, dolomite) is possibly related to varying dissolved sulphate concentrations in the diagenetic environment. Fluid inclusion microthermometry and Raman spectroscopy indicate the presence of an aqueous + hydrocarbon mixture inside the inclusions. This seepage mixture was almost certainly immiscible, resulting in heterogeneous trapping.
New dates (415 Ma) for the Etive Dyke Swarm and the end of the Caledonian Orogeny in the SW Grampian Highlands of Scotland
Authors: MORRIS G. A. , PAGE L. , MARTINEZ V.
Published: August 2005

New laser stepwise heating
40
Ar–
39
Ar dates (415 ± 1.8 and 414 ± 2 Ma) from the Etive Dyke Swarm in the SW Grampian Highlands of Scotland indicate that the dykes are 10–20 Ma older than previously assumed. The dykes constitute the final phase of the Late Caledonian Granites in the region, which themselves define the end of the Caledonian Orogeny, therefore these dates can be taken as the end of the orogeny in this area. The dates show a temporal link between the Etive magmatism and early precious metal mineralization at Tyndrum as well as emphasizing the NW to SE diachronous nature of the end of Caledonian magmatism across Scotland.
Kimberlite trends in NW Canada
Authors: Snyder D. B. , Lockhart G. D.
Published: August 2005

Kimberlite deposits attract much interest as the host rock for diamonds, but their eruption mechanisms and deep root structure remain poorly perceived. Independent geochronological and seismic shear-wave anisotropy studies in NW Canada near the world's newest diamond mines revealed an unexpected correlation in structural trends. Age of eruption grouped 36 kimberlites into linear clusters; forward modelling of shear-wave delays indicated two distinct layers of seismic anisotropy with a boundary about 120 km deep. The similarity of inferred age and trend direction at surface and at depth indicates that these kimberlites erupted along lithospheric-scale fractures oriented by continental stress fields related to North American plate motions.
Mid-Jurassic age for the Botany Bay Group: implications for Weddell Sea Basin creation and southern hemisphere biostratigraphy
Authors: Hunter Morag A. , Cantrill David J. , Flowerdew Michael J. , Millar Ian L.
Published: August 2005

New U–Pb zircon ion-microprobe ages from the alluvial conglomerates and flood plain sediments of the Botany Bay Group demonstrate that sedimentation occurred at

c.

167 Ma, coeval with rift-related silicic volcanism in the northern Antarctic Peninsula. In contrast, rift-related volcanism and sedimentation in the southern Antarctic Peninsula (Latady Basin) occurred at

c.

183 Ma. The new data indicate that syn-rift sedimentation and volcanism was diachronous from south to north, consistent with early opening of the Weddell Sea embayment by anti-clockwise rotation of the Antarctic Peninsula in the Mid-Jurassic. A definitive date for the Botany Bay Group floras has important implications for Southern Hemisphere biostratigraphic correlations.
Enzyme Replacement for Lysosomal Diseases
Authors: Brady Roscoe O.
Published: August 2005

Following the demonstration of the nature of the enzymatic defects in the sphingolipid storage disorders in the mid-1960s, consideration was directed to the development of therapy for patients with these conditions. High on the list of possibilities was enzyme supplementation or replacement. Many years of arduous investigation and the development of novel protein targeting strategies were required to bring this concept to fruition. Enzyme replacement therapy (ERT) was eventually shown to be extraordinarily effective for patients with Gaucher disease, the most prevalent metabolic storage disorder of humans. Demonstration of the benefit of ERT in this disorder led to the extension of this approach to the treatment of other lysosomal storage disorders. This review presents the current status and anticipated developments in this field.
Osteoactivin upregulates expression of MMP-3 and MMP-9 in fibroblasts infiltrated into denervated skeletal muscle in mice
Authors: Ogawa Takayuki , Nikawa Takeshi , Furochi Harumi , Kosyoji Miki , Hirasaka Katsuya , Suzue Naoto , Sairyo Koichi , Nakano Shunji , Yamaoka Takashi , Itakura Mitsuo , Kishi Kyoichi , Yasui Natsuo
Published: August 2005

In this study, we examined pathophysiological roles of osteoactivin, a functionally unknown type I membrane glycoprotein, in mouse skeletal muscle atrophied by denervation (sciatic neurectomy). Denervation increased the amounts of osteoactivin, vimentin, matrix metalloproteinase-3 (MMP-3), and MMP-9 in mouse gastrocnemius muscle. Interestingly, immunohistochemical analysis revealed that vimentin, MMP-3, and MMP-9 were mainly present in fibroblast-like cells infiltrated into denervated mouse gastrocnemius muscle, whereas osteoactivin was expressed in the sarcolemma of myofibers adjacent to the fibroblast-like cells. On the basis of these findings, we reasoned that osteoactivin in myocytes was involved in activation of the infiltrated fibroblasts. To address this issue, we examined effects of osteoactivin on expression of MMPs in fibroblasts in vitro and in vivo. Overexpression of osteoactivin in NIH-3T3 fibroblasts induced expression of MMP-3, but not in mouse C2C12 myoblasts, indicating that osteoactivin might functionally target fibroblasts. Treatment with recombinant mouse osteoactivin increased the amounts of collagen type I, MMP-3, and MMP-9 in mouse NIH-3T3 fibroblasts. The upregulated expression of these fibroblast marker proteins was significantly inhibited by heparin, but not by an integrin inhibitor, indicating that a heparin-binding motif in the extracellular domain might be an active site of osteoactivin. In osteoactivin-transgenic mice, denervation further enhanced expression of MMP-3 and MMP-9 in fibroblasts infiltrated into gastrocnemius muscle, compared with wild-type mice. Our present results suggest that osteoactivin might function as an activator for fibroblasts infiltrated into denervated skeletal muscles and play an important role in regulating degeneration/regeneration of extracellular matrix.
Phosphatidylcholine transfer protein regulates size and hepatic uptake of high-density lipoproteins
Authors: Wu Michele K. , Cohen David E.
Published: August 2005

Phosphatidylcholine transfer protein (PC-TP) is a steroidogenic acute regulatory-related transfer domain protein that is enriched in liver cytosol and binds phosphatidylcholines with high specificity. In tissue culture systems, PC-TP promotes ATP-binding cassette protein A1-mediated efflux of cholesterol and phosphatidylcholine molecules as nascent pre-β-high-density lipoprotein (HDL) particles. Here, we explored a role for PC-TP in HDL metabolism in vivo utilizing 8-wk-old male Pctp−/−and wild-type littermate C57BL/6J mice that were fed for 7 days with either chow or a high-fat/high-cholesterol diet. In chow-fed mice, neither plasma cholesterol concentrations nor the concentrations and compositions of plasma phospholipids were influenced by PC-TP expression. However, in Pctp−/−mice, there was an accumulation of small α-migrating HDL particles. This occurred without changes in hepatic expression of ATP-binding cassette protein A1 or in proteins that regulate the intravascular metabolism and clearance of HDL particles. In Pctp−/−mice fed the high-fat/high-cholesterol diet, HDL particle sizes were normalized, whereas plasma cholesterol and phospholipid concentrations were increased compared with wild-type mice. In the absence of upregulation of hepatic ATP-binding cassette protein A1, reduced HDL uptake from plasma into livers of Pctp−/−mice contributed to higher plasma lipid concentrations. These data indicate that PC-TP is not essential for the enrichment of HDL with phosphatidylcholines but that it does modulate particle size and rates of hepatic clearance.
Reduction in interaction between cGMP and cAMP in dog ventricular myocytes with hypertrophic failure
Authors: Zhang Qihang , Lazar Michael , Molino Bruno , Rodriguez Roberto , Davidov Tomer , Su Jun , Tse James , Weiss Harvey R. , Scholz Peter M.
Published: August 2005

Baseline function and signal transduction are depressed in hearts with hypertrophic failure. We tested the hypothesis that the effects of cGMP and its interaction with cAMP would be reduced in cardiac myocytes from hypertrophic failing hearts. Ventricular myocytes were isolated from control dogs, dogs with aortic valve stenosis hypertrophy, and dogs with pacing hypertrophic failure. Myocyte function was measured using a video edge detector. Cell contraction data were obtained at baseline, with 8-bromo-cGMP (10−7, 10−6, and 10−5 M), with erythro-9-(2-hydroxy-3-nonyl)adenine [EHNA; a cAMP phosphodiesterase (PDE2) inhibitor] plus 8-bromo-cGMP, or milrinone (a PDE3 inhibitor) plus 8-bromo-cGMP. Baseline percent shortening and maximal rates of shortening (Rmax) and relaxation were slightly reduced in hypertrophic myocytes and were significantly lower in failing myocytes (Rmax: control dogs, 95.3 ± 17.3; hypertrophy dogs, 88.2 ± 5.5; failure dogs, 53.2 ± 6.4 μm/s). 8-Bromo-cGMP dose dependently reduced myocyte function in all groups. However, EHNA (10−6 M) and milrinone (10−6 M) significantly reduced the negative effects of cGMP on cell contractility in control and hypertrophy but not in failing myocytes (Rmax for control dogs: cGMP, −46%; +EHNA, −21%; +milrinone, −19%; for hypertrophy dogs: cGMP, −40%; +EHNA, −13%; +milrinone, −20%; for failure dogs: cGMP, −40%; +EHNA, −29%; +milrinone, −32%). Both combinations of EHNA-cGMP and milrinone-cGMP significantly increased intracellular cAMP in control, hypertrophic, and failing myocytes. These data indicated that the cGMP signaling pathway was preserved in hypertrophic failing cardiac myocytes. However, the interaction of cGMP with the cAMP signaling pathway was impaired in these failing myocytes.
Long-term hypoxia represses the expression of key genes regulating cortisol biosynthesis in the near-term ovine fetus
Authors: Myers Dean A. , Hyatt Kimberly , Mlynarczyk Malgorzata , Bird Ian M. , Ducsay Charles A.
Published: August 2005

Basal plasma ACTH1–39 concentrations are elevated in long-term hypoxic (LTH) fetal sheep. This study was designed to determine whether the expression of genes regulating cortisol biosynthesis was altered after LTH. Pregnant ewes were maintained at high altitude (3,820 m) from day 30 of gestation to near term, when the animals were transported to the laboratory. Reduced Po2 was maintained by nitrogen infusion through a maternal tracheal catheter. On days 137–141, fetal adrenal glands were collected from LTH and normoxic control fetuses. Real-time PCR was used to quantify mRNA for steroidogenic acute regulatory protein, 17α-hydroxylase (CYP17), 21-hydroxylase (CYP21), cholesterol side-chain cleavage (CYP11A1), 3β-hydroxysteroid dehydrogenase type II (HSD3B2), and the ACTH receptor. We analyzed mRNA by slot-blot hybridization and also quantified mRNA for transcription factors necessary for adrenocortical development by quantitative real-time PCR: steroidogenic factor 1 and dosage-sensitive sex reversal, adrenal hypoplasia congenital, critical region on the X chromosome (DAX-1). Protein was quantified by Western blot analysis. Adrenal mRNAs for CYP17, CYP11A1, and the ACTH receptor were significantly reduced in LTH fetal sheep compared with levels shown in controls. Similarly, CYP11A1 protein and CYP17 protein were reduced in the LTH group. CYP21, steroidogenic acute regulatory protein, HSD3B2, steroidogenic factor 1, and DAX-1 expressions were not altered in response to LTH. We conclude that expression of two key steroidogenic enzymes (CYP17, CYP11A1) regulating cortisol biosynthesis and the ACTH receptor is lower in response to LTH. This likely represents an adaptive response to LTH, to prevent excessive cortisol production that would restrict fetal growth and potentially induce preterm delivery.
Spinal cord injury-induced changes in breathing are not due to supraspinal plasticity in turtles (Pseudemys scripta)
Authors: Johnson Stephen M. , Creighton Robert J.
Published: August 2005

After occurrence of spinal cord injury, it is not known whether the respiratory rhythm generator undergoes plasticity to compensate for respiratory insufficiency. To test this hypothesis, respiratory variables were measured in adult semiaquatic turtles using a pneumotachograph attached to a breathing chamber on a water-filled tank. Turtles breathed room air (2 h) before being challenged with two consecutive 2-h bouts of hypercapnia (2 and 6% CO2or 4 and 8% CO2). Turtles were spinalized at dorsal segments D8–D10so that only pectoral girdle movement was used for breathing. Measurements were repeated at 4 and 8 wk postinjury. For turtles breathing room air, breathing frequency, tidal volume, and ventilation were not altered by spinalization; single-breath (singlet) frequency increased sevenfold. Spinalized turtles breathing 6–8% CO2had lower ventilation due to decreased frequency and tidal volume, episodic breathing (breaths/episode) was reduced, and singlet breathing was increased sevenfold. Respiratory variables in sham-operated turtles were unaltered by surgery. Isolated brain stems from control, spinalized, and sham turtles produced similar respiratory motor output and responded the same to increased bath pH. Thus spinalized turtles compensated for pelvic girdle loss while breathing room air but were unable to compensate during hypercapnic challenges. Because isolated brain stems from control and spinalized turtles had similar respiratory motor output and chemosensitivity, breathing changes in spinalized turtles in vivo were probably not due to plasticity within the respiratory rhythm generator. Instead, caudal spinal cord damage probably disrupts spinobulbar pathways that are necessary for normal breathing.
Alterations in Internal Elastic Lamina Permeability As a Function of Age and Anatomical Site Precede Lesion Development in Apolipoprotein E–Null Mice
Authors: Lee Kwangdeok , Forudi Farhad , Saidel Gerald M. , Penn Marc S.
Published: August 2005

Early atherosclerosis is characterized by the accumulation of plasma-borne macromolecules (eg, low-density lipoproteins) in the arterial intima, which is bordered by endothelial cells (EC) and the internal elastic lamina (IEL). This accumulation is believed to be secondary to increased EC permeability. We hypothesized that a decrease in IEL permeability may precede lesion development and contribute to macromolecular accumulation. To test this hypothesis, we quantified EC and IEL permeability in lesion-free areas of the thoracic and abdominal aortas of chow-fed C57BL/6 control and atherosclerotic-prone apolipoprotein E (apoE)-null mice at 3 and 5 months of age. Between 3 and 5 months of age, apoE-null mice begin to develop atherosclerotic lesions in the thoracic aorta. No significant differences in EC and IEL permeability were observed at either time in C57BL/6 control mice. In contrast, 78% and 19% decreases in IEL permeability of the thoracic aorta and abdominal aorta, respectively, were observed between 3 to 5 months of age in apoE-null mice (thoracic: 2.05±1.33 and 0.44±0.15 μm/min,
P
<0.001; abdominal: 1.13±0.58 and 0.93±0.44 μm/min,
P
<0.05). To further determine whether decreased IEL permeability is linked with atherosclerotic lesion development, we quantified IEL permeability in the greater and lesser curvature of the aortic arch. In apoE-null mice, the lesser curvature of the aortic arch develops lesions before the greater curvature. We found a significant and sustained decrease (59%) in IEL permeability in the lesser curvature of the aortic arch compared with the greater curvature. These data suggest that atherogenesis involves the pathological remodeling of the IEL, not the endothelium before lesion development. This remodeling may be attributable to local responses of the endothelium and smooth muscle cells to hyperlipidemia.
The Prediction of Malignant Cerebral Infarction by Molecular Brain Barrier Disruption Markers
Authors: Serena Joaquın , Blanco Miguel , Castellanos Mar , Silva Yolanda , Vivancos José , Moro Marıa Angeles , Leira Rogelio , Lizasoain Ignacio , Castillo José , Dávalos Antonio
Published: August 2005

Background and Purpose—

Space-occupying brain edema is a life-threatening complication in patients with large hemispheric stroke. The aim of the study was to determine whether molecular markers of endothelial damage may help to predict secondary brain edema and, secondly, to identify patients who could benefit from aggressive therapies such as decompressive hemicraniectomy or hypothermia.

Methods—

We studied 40 consecutive patients with malignant middle cerebral artery (MCA) infarction and 35 controls with massive MCA infarctions <70 years of age and matched by stroke severity on admission. Cranial computed tomography (CT) was performed at entry and repeated between days 4 and 7, or earlier if there was neurological worsening. Malignant MCA (m-MCA) infarction was diagnosed when follow-up CT detected a more than two-thirds space-occupying MCA infarction with midline shift, compression of the basal cisterns, and neurological deterioration. Plasma concentrations of glutamate, glycine, γ-aminobutyric acid, interleukin-6 (IL-6), IL-10, tumor necrosis factor-α, matrix metalloproteinase-9 (MMP-9), and cellular-fibronectin (c-Fn) were determined in blood samples obtained at admission.

Results—

Mean time from stroke onset to blood sampling was 6.3±4.8 in m-MCA and 7.7±6.0 hours in the control group (
P
=0.63). Baseline characteristics were comparable in both groups. c-Fn and MMP-9 levels were significantly higher in patients with m-MCA than in controls (all
P
<0.001). c-Fn >16.6 μg/mL had the highest sensitivity (90%), specificity (100%), and negative and positive predictive values (89% and 100%, respectively) for the prediction of m-MCA infarction.

Conclusions—

A plasma c-Fn concentration >16.6 μg/mL at admission is associated with the development of m-MCA infarction with high sensitivity and specificity, suggesting that c-Fn might be useful in therapeutic decision making.
Is It Time for a Large, Collaborative Study of Pediatric Stroke?
Authors: Zahuranec Darin B. , Brown Devin L. , Lisabeth Lynda D. , Morgenstern Lewis B.
Published: August 2005

Background and Purpose—

A 2002 report from the National Institute of Neurological Disorders and Stroke cited the critical importance of more childhood stroke studies. We present the incidence rate of pediatric stroke from a biethnic community-based project and calculate the population size required for future prospective studies of pediatric stroke.

Methods—

This work is part of the Brain Attack Surveillance in Corpus Christi (BASIC) project. The community of 325 000 is located in southeast Texas and is composed of approximately equal numbers of Mexican Americans (MAs) and non-Hispanic whites (NHWs). Discharge diagnosis codes from all hospitals in the county were used to identify cases of childhood stroke (age >1 month and <20 years) in 2002 and 2003, and stroke cases were validated by source document review. On the basis of the incidence rates, the population size required to complete a case-control study to examine risk factors for pediatric stroke was calculated.

Results—

Eight cases of pediatric stroke were identified, yielding an annual incidence rate of 4.3 per 100 000 (95% CI, 1.9 to 8.5). There were 5 cases of intracerebral hemorrhage, 1 subarachnoid hemorrhage, 1 ischemic stroke, and 1 transient ischemic attack. All of the events occurred in MAs. Depending on the prevalence of the risk factors of interest, future studies of pediatric stroke would have to draw from a population of up to 59 million children to complete a case-control study within 4 years.

Conclusions—

Given the rarity of pediatric stroke, future studies will require multicenter efforts and possibly a national surveillance system.
Cerebral Vein and Dural Sinus Thrombosis in Elderly Patients
Authors: Ferro José M. , Canhão Patrícia , Bousser Marie-Germaine , Stam Jan , Barinagarrementeria Fernando
Published: August 2005

Backgound and Purpose—

The clinical features and prognosis of cerebral vein and dural sinus thrombosis (CVT) in elderly patients have not been previously described.

Methods—

In a multicenter prospective observational study, we compared clinical and imaging features, risk factors, and outcome of adult patients aged <65 (young and middle-aged patients) and ≥65 years (elderly patients).

Results—

A total of 624 adult patients with CVT were registered and followed-up for a median of 16 months. Fifty-one (8.2%) were aged ≥65 years. Presentation as an isolated intracranial hypertension syndrome was less frequent in elderly patients (4/51 versus 139/573,
P
=0.008), whereas depressed consciousness (17 versus 97,
P
=0.005), and mental status changes (22 versus 115,
P
=0.001) were more frequent in the elderly. The prognosis of elderly patients was considerably worse than that of younger patients, as only 49% of elderly patients made a complete recovery (versus 82% in younger patients), whereas 27% died and 22% were dependent at the end of follow-up (versus 7 and 2% respectively in younger patients). Carcinoma (5 cases) was more frequent as a risk factor for CVT in elderly patients (
P
=0.017). During follow-up, elderly patients were more likely to experience thrombotic events (HR=4.8, 95% CI=1.9 to 11.9) and were less likely to experience severe headaches (HR=0.2, 95% CI=0.02, 0.97).

Conclusions—

Elderly patients with CVT have a distinctive clinical presentation: isolated intracranial hypertension is uncommon, whereas mental status and alertness disturbances are common. The prognosis of CVT is worse in elderly patients.
Promoter Polymorphisms in the Nitric Oxide Synthase 3 Gene Are Associated With Ischemic Stroke Susceptibility in Young Black Women
Authors: Howard Timothy D. , Giles Wayne H. , Xu Jianfeng , Wozniak Marcella A. , Malarcher Ann M. , Lange Leslie A. , Macko Richard F. , Basehore Monica J. , Meyers Deborah A. , Cole John W. , Kittner Steven J.
Published: August 2005

Background and Purpose—

Endothelial nitric oxide exerts a variety of protective effects on endothelial cells and blood vessels, and therefore the nitric oxide synthase 3 gene (
NOS3
) is a logical candidate gene for stroke susceptibility.

Methods—

We used the population-based Stroke Prevention in Young Women case-control study to assess the association of five
NOS3
polymorphisms in 110 cases (46% black) with ischemic stroke and 206 controls (38% black), 15 to 44 years of age. Polymorphisms included 3 single nucleotide polymorphisms (SNPs) in the promoter region (−1468 T>A, −922 G>A, −786 T>C), 1 SNP in exon 7 (G894T), and 1 insertion/deletion polymorphism within intron 4.

Results—

Significant associations with both the −922 G>A and −786 T>C SNPs with ischemic stroke were observed in the black, but not the white, population. This association was attributable to an increased prevalence of the −922 A allele (OR=3.0, 95% CI=1.3 to 6.8;
P
=0.005) and the -786 T allele (OR=2.9, 95% CI=1.3 to 6.4;
P
=0.005) in cases versus controls. These 2 SNPs were in strong linkage disequilibrium (D′=1.0), making it impossible to determine, within the confines of this genetic study, whether 1 or both of these polymorphisms are functionally related to
NOS3
expression. Two sets of haplotypes were also identified, 1 of which may confer an increased susceptibility to stroke in blacks, whereas the other appears to be protective.

Conclusion—

Promoter variants in
NOS3
may be associated with ischemic stroke susceptibility among young black women.
The genomic environment around the Aromatase gene: evolutionary insights
Authors: Castro L Filipe C , Santos Miguel M , Reis-Henriques Maria A
Published: August 2005

Background

The cytochrome P450 aromatase (CYP19), catalyses the aromatisation of androgens to estrogens, a key mechanism in vertebrate reproductive physiology. A current evolutionary hypothesis suggests that CYP19 gene arose at the origin of vertebrates, given that it has not been found outside this clade. The human CYP19 gene is located in one of the proposed MHC-paralogon regions (HSA15q). At present it is unclear whether this genomic location is ancestral (which would suggest an invertebrate origin for CYP19) or derived (genomic location with no evolutionary meaning). The distinction between these possibilities should help to clarify the timing of the CYP19 emergence and which taxa should be investigated.

Results

Here we determine the "genomic environment" around CYP19 in three vertebrate species Homo sapiens, Tetraodon nigroviridis and Xenopus tropicalis. Paralogy studies and phylogenetic analysis of six gene families suggests that the CYP19 gene region was structured through "en bloc" genomic duplication (as part of the MHC-paralogon formation). Four gene families have specifically duplicated in the vertebrate lineage. Moreover, the mapping location of the different paralogues is consistent with a model of "en bloc" duplication. Furthermore, we also determine that this region has retained the same gene content since the divergence of Actinopterygii and Tetrapods. A single inversion in gene order has taken place, probably in the mammalian lineage. Finally, we describe the first invertebrate CYP19 sequence, from Branchiostoma floridae.

Conclusion

Contrary to previous suggestions, our data indicates an invertebrate origin for the aromatase gene, given the striking conservation pattern in both gene order and gene content, and the presence of aromatase in amphioxus. We propose that CYP19 duplicated in the vertebrate lineage to yield four paralogues, followed by the subsequent loss of all but one gene in vertebrate evolution. Finally, we suggest that agnathans and lophotrocozoan protostomes should be investigated for the presence of aromatase.
Transcribed Tc1-like transposons in salmonid fish
Authors: Krasnov Aleksei , Koskinen Heikki , Afanasyev Sergey , Mölsä Hannu
Published: August 2005

Background

Mobile genetic elements comprise a substantial fraction of vertebrate genomes. These genes are considered to be deleterious, and in vertebrates they are usually inactive. High throughput sequencing of salmonid fish cDNA libraries has revealed a large number of transposons, which remain transcribed despite inactivation of translation. This article reports on the structure and potential role of these genes.

Results

A search of EST showed the ratio of transcribed transposons in salmonid fish (i.e., 0.5% of all unique cDNA sequences) to be 2.4–32 times greater than in other vertebrate species, and 68% of these genes belonged to the Tc1-family of DNA transposons. A phylogenetic analysis of reading frames indicate repeated transposition of distantly related genes into the fish genome over protracted intervals of evolutionary time. Several copies of two new DNA transposons were cloned. These copies showed relatively little divergence (11.4% and 1.9%). The latter gene was transcribed at a high level in rainbow trout tissues, and was present in genomes of many phylogenetically remote fish species. A comparison of synonymous and non-synonymous divergence revealed remnants of divergent evolution in the younger gene, while the older gene evolved in a neutral mode. From a 1.2 MB fragment of genomic DNA, the salmonid genome contains approximately 105 Tc1-like sequences, the major fraction of which is not transcribed. Our microarray studies showed that transcription of rainbow trout transposons is activated by external stimuli, such as toxicity, stress and bacterial antigens. The expression profiles of Tc1-like transposons gave a strong correlation (r2 = 0.63–0.88) with a group of genes implicated in defense response, signal transduction and regulation of transcription.

Conclusion

Salmonid genomes contain a large quantity of transcribed mobile genetic elements. Divergent or neutral evolution within genomes and lateral transmission can account for the diversity and sustained persistence of Tc1-like transposons in lower vertebrates. A small part of transposons remain transcribed and their transcription is enhanced by responses to acute conditions.
A nested-PCR with an Internal Amplification Control for the detection and differentiation of Bartonella henselae and B. clarridgeiae: An examination of cats in Trinidad
Authors: Rampersad Joanne N , Watkins John D , Samlal Michael S , Deonanan Raymond , Ramsubeik Shalini , Ammons David R
Published: August 2005

Background

Bartonella species are bacterial blood parasites of animals capable of causing disease in both animals and man. Cat-Scratch Disease (CSD) in humans is caused mainly by Bartonella henselae and is acquired from the cat, which serves as a reservoir for the bacteria. A second species, B. clarridgeiae is also implicated in the disease. Diagnosis of Bartonellosis by culture requires a week or more of incubation on enriched media containing blood, and recovery is often complicated by faster growing contaminating bacteria and fungi. PCR has been explored as an alternative to culture for both the detection and species identification of Bartonella, however sensitivity problems have been reported and false negative reactions due to blood inhibitors have not generally been addressed in test design.

Methods

A novel, nested-PCR was designed for the detection of Bartonella henselae and B. clarridgeiae based on the strategy of targeting species-specific size differences in the 16S-23S rDNA intergenic regions. An Internal Amplification Control was used for detecting PCR inhibition. The nested-PCR was utilized in a study on 103 blood samples from pet and stray cats in Trinidad.

Results

None of the samples were positive by primary PCR, but the Nested-PCR detected Bartonella in 32/103 (31%) cats where 16 were infected with only B. henselae, 13 with only B. clarridgeiae and 3 with both species. Of 22 stray cats housed at an animal shelter, 13 (59%) were positive for either or both species, supporting the reported increased incidence of Bartonella among feral cats.

Conclusion

The usefulness of a single PCR for the detection of Bartonella henselae and B. clarridgeiae in the blood of cats is questionable. A nested-PCR offers increased sensitivity over a primary PCR and should be evaluated with currently used methods for the routine detection and speciation of Bartonella henselae and B. clarridgeiae. In Trinidad, B. henselae and B. clarridgeiae are the predominant species in cats and infection appears highest with stray cats, however B. clarridgeiae may be present at levels similar to that of B. henselae in the pet population.
DNA index determination with Automated Cellular Imaging System (ACIS) in Barrett's esophagus: Comparison with CAS 200
Authors: Huang Qin , Yu Chenggong , Klein Michael , Fang James , Goyal Raj K
Published: August 2005

Background

For solid tumors, image cytometry has been shown to be more sensitive for diagnosing DNA content abnormalities (aneuploidy) than flow cytometry. Image cytometry has often been performed using the semi-automated CAS 200 system. Recently, an Automated Cellular Imaging System (ACIS) was introduced to determine DNA content (DNA index), but it has not been validated.

Methods

Using the CAS 200 system and ACIS, we compared the DNA index (DI) obtained from the same archived formalin-fixed and paraffin embedded tissue samples from Barrett's esophagus related lesions, including samples with specialized intestinal metaplasia without dysplasia, low-grade dysplasia, high-grade dysplasia and adenocarcinoma.

Results

Although there was a very good correlation between the DI values determined by ACIS and CAS 200, the former was 25% more sensitive in detecting aneuploidy. ACIS yielded a mean DI value 18% higher than that obtained by CAS 200 (p < 0.001; paired t test). In addition, the average time required to perform a DNA ploidy analysis was shorter with the ACIS (30–40 min) than with the CAS 200 (40–70 min). Results obtained by ACIS gave excellent inter-and intra-observer variability (coefficient of correlation >0.9 for both, p < 0.0001).

Conclusion

Compared with the CAS 200, the ACIS is a more sensitive and less time consuming technique for determining DNA ploidy. Results obtained by ACIS are also highly reproducible.