bluuebunny/crossref_metadata_2025 huggingface dataset:
Ab initio studies of the electronic structure of Be93, Be105, Be111, and Be123 clusters
Authors: Ross R. B. , Kern C. W. , Pitzer R. M. , Ermler W. C.
Published: December 2004

Ab initio self‐consistent‐field calculations are reported for electronic states of beryllium clusters comprised of 93, 105, 111, and 123 atoms. The respective clusters correspond to coordination shells 12‐15 of a central Be atom with internuclear separations derived from the lattice constants of the bulk metal. Ab initio effective core potentials have been employed to replace the 1 s electrons, thereby reducing the complexity of the calculations. In addition, use of the full D3h point group symmetry of the clusters results in a substantial reduction of the numbers of two‐electron integrals that must be computed and processed. Binding energies, orbital energies, electric field gradient, nuclear‐electrostatic potential, diamagnetic shielding constant, second moments, and Mulliken populations are calculated for selected electronic states. Calculated binding energies when compared among the different clusters as well as to smaller and larger fragments from earlier studies provide evidence for the onset of convergence to the Hartree–Fock limit of the bulk. Lowest‐state ionization potentials are consistently above and agree to within 14% of the experimental workfunction. The net charge on the central beryllium atom decreases toward zero. The variability of observed bulklike behavior for the different properties indicates that the transition between cluster and bulklike behavior is not sharp and depends on the quantity of interest. © 1995 John Wiley & Sons, Inc.
Thermospheric gravity wave modes over low and equatorial latitudes during daytime
Authors: Chakrabarty D. , Sekar R. , Narayanan R. , Pant Tarun Kumar , Niranjan K.
Published: December 2004

The small‐scale intensity fluctuations obtained from 56 days of observations of OI 630.0 nm dayglow emission intensities from Mount Abu (24.6°N, 73.7°E, dip latitude 19.09°N), a station under the crest of equatorial ionization anomaly (EIA), have been subjected to harmonic analysis to unravel different modes of atmospheric gravity waves (AGW). Similar analysis is carried out for 26 days of dayglow intensity data recorded from Waltair (17.7°N, 83.3°E, dip latitude 10.09°N), a low‐latitude station, and for 8 days of available data from Thumba (8.68°N, 77.0°E, dip latitude 0.45°N), an equatorial station with the same objective. The analysis reveals the relative dominance (“preferred mode”) of 0.5–1.0 hour periodic component over Mount Abu, 2.0–2.5 hour periodic component over Waltair, and 1.0–1.5 hour component over Thumba during geomagnetically quiet periods. Qualitative arguments have been propounded to explain the differences in the preferred modes over these places, and it is suggested that the source responsible for the preferred modes may lie in the lower atmosphere. Further, the analysis also indicates the presence of additional preferred modes over low latitudes during geomagnetically disturbed periods.
Numerical simulation of the combined system of nighttime region 0, region 1, and region 2 field‐aligned currents
Authors: Yamamoto T. , Inoue S.
Published: December 2004

A numerical simulation is performed to identify the physical mechanisms for the generation of the nighttime region 0 and region 1 field‐aligned currents (FACs) in conditions of a steady solar wind with a southward or weak interplanetary magnetic field. The generation of region 0/region 1 FACs observed near the poleward edge of the auroral oval is closely associated with the dynamics of ion beams produced by nonadiabatic acceleration in the tail current sheet. After ejection from the current sheet, ion beams advance toward the Earth along the nearly straight field lines. During such a time interval, the ions have insignificant magnetic drift velocities. Subsequently, they are reflected at low‐altitude mirror points, and under the influence of inward convection they pass the equator on magnetic shells that are further in. At that moment they attain large magnetic (curvature) drift velocities. Accordingly, in a steady state, the magnetic drift speed averaged over all the ions in a flux tube increases with decreasing invariant latitude; it starts to increase significantly at a certain magnetic shell. In the present paper this magnetic shell is identified with the interface demarcating the nonadiabatic and adiabatic regions in the tail current sheet. An essential point for the region 1 FAC generation is distortion of this interface, namely inclination of the interface to the direction of the average magnetic drift velocity. The generation of region 0 FACs is due to anomalous cross‐field diffusion of energized ions near the poleward edge of the auroral oval. Latitudinal profiles of magnetic field perturbations arising from region 0/region 1 FACs in the simulation are remarkably similar to observed magnetic field signatures of the region 0/region 1 thin‐current‐sheet systems.
Coupling of a global MHD code and an inner magnetospheric model: Initial results
Authors: De Zeeuw Darren L. , Sazykin Stanislav , Wolf Richard A. , Gombosi Tamas I. , Ridley Aaron J. , Tóth Gabor
Published: December 2004

This paper describes the coupling of BATS‐R‐US (Block Adaptive Tree Solar‐wind Roe‐type Upwind Scheme), a magnetohydrodynamics (MHD) code representing the Earth's global magnetosphere and its coupling to the ionosphere and solar wind, and the Rice Convection Model (RCM), which represents the inner magnetosphere and its coupling to the ionosphere. The MHD code provides a time‐evolving magnetic field model for the RCM as well as continuously updated boundary conditions for the electric potential and plasma. The RCM computes the distribution functions of inner magnetospheric particles, including transport of inner plasmasheet and ring current particles by gradient/curvature drifts; it thus calculates more accurate inner magnetospheric pressures, which are frequently passed to the MHD model and used to nudge the MHD values. Results are presented for an initial run with the coupled code for the case of uniform ionospheric conductance with steady solar wind and southward interplanetary magnetic field (IMF). The results are compared with those for a run of the MHD code alone. The coupled‐code run shows significantly higher inner magnetospheric particle pressures. It also exhibits several well‐established characteristics of inner magnetospheric electrodynamics, including strong region‐2 Birkeland currents and partial shielding of the inner magnetosphere from the main force of the convection electric field. A sudden northward turning of the IMF causes the ring current to become more nearly symmetric. The inner magnetosphere exhibits an overshielding (dusk‐to‐dawn) electric field that begins about 10 min after the northward turning reaches the magnetopause and lasts just over an hour.
Cenozoic evolution of the northwestern Salar de Atacama Basin, northern Chile
Authors: Pananont P. , Mpodozis C. , Blanco N. , Jordan T. E. , Brown L. D.
Published: December 2004

Since 90 Ma, the nonmarine Salar de Atacama Basin has been the largest, deepest, and most persistent sedimentary basin of northern Chile. Integration of 200 km of two‐dimensional seismic reflection data with surface geological data clarifies Oligocene and Neogene evolution of the northern part of the basin. A normal fault with 6 ± 1 km of vertical separation controlled the western boundary of the basin during the accumulation of the Oligocene–lower Miocene Paciencia Group. The combination of this structure, a similar one in the Calama Basin, and regional structural data suggests that localized extension played an important role within a tectonic environment dominated by margin‐perpendicular compression and margin‐parallel strike‐slip deformation. Seismic data substantiate the surface interpretation that much of the Cordillera de la Sal ridge resulted from diapiric flow of the Paciencia Group. Diapiric flow initiated during the late early Miocene or middle Miocene, associated with a deep reverse fault.
Oceanic and atmospheric transport of multiyear El Niño–Southern Oscillation (ENSO) signatures to the polar regions
Authors: Jevrejeva S. , Moore J. C. , Grinsted A.
Published: December 2004

Using Monte‐Carlo Singular Spectrum Analysis (MC‐ SSA) and Wavelet Transform (WT) we separate statistically significant components from time series and demonstrate significant co‐variance and consistent phase differences between ice conditions and the Arctic Oscillation and Southern Oscillation indices (AO and SOI) at 2.2, 3.5, 5.7 and 13.9 year periods. The 2.2, 3.5 and 5.7 year signals detected in the Arctic are generated about three months earlier in the tropical Pacific Ocean. In contrast, we show that the 13.9 year signal propagates eastward from the western Pacific as equatorial coupled waves (ECW, 0.13–0.15 ms−1), and then as fast boundary waves (1–3 ms−1) along the western margins of the Americas, with a phase difference of about 1.8–2.1 years by the time they reach the Arctic. Our results provide evidence of dynamical connections between high latitude surface conditions, tropical ocean sea surface temperatures mediated by tropical wave propagation, the wintertime polar vortex and the AO.
Effects of future climate change on regional air pollution episodes in the United States
Authors: Mickley L. J. , Jacob D. J. , Field B. D. , Rind D.
Published: December 2004

We examine the impact of future climate change on regional air pollution meteorology in the United States by conducting a transient climate change (1950–2052) simulation in a general circulation model (GCM) of the Goddard Institute of Space Studies (GISS). We include in the GCM two tracers of anthropogenic pollution, combustion carbon monoxide (COt) and black carbon (BCt). Sources of both tracers and the loss frequency of COt are held constant in time, while wet deposition of BCt responds to the changing climate. Results show that the severity and duration of summertime regional pollution episodes in the midwestern and northeastern United States increase significantly relative to present. Pollutant concentrations during these episodes increase by 5–10% and the mean episode duration increases from 2 to 3–4 days. These increases appear to be driven by a decline in the frequency of mid‐latitude cyclones tracking across southern Canada. The cold fronts associated with these cyclones are known to provide the main mechanism for ventilation of the midwestern and northeastern United States. Mid‐latitude cyclone frequency is expected to decrease in a warmer climate; such a decrease is already apparent in long‐term observations. Mixing depths over the midwest and northeast increase by 100–240 m in our future‐climate simulation, not enough to compensate for the increased stagnation resulting from reduced cyclone frequency.
Salinity trends on the Siberian shelves
Authors: Steele Michael , Ermold Wendy
Published: December 2004

We present an analysis of observed long‐term (∼100 year) salinity trends on the freshwater‐dominated Siberian continental shelves. A multiple regression was performed in the White Sea (WS), the Kara Sea (KS), the Laptev Sea (LS), and the East Siberian Sea (ESS). Since 1930, the WS has gained freshwater while the ESS has lost it, consistent with river discharge trends over this period. Over the past 20 years, increases in both river discharge and direct precipitation can explain observed salinity decreases in the WS, but not in the KS. Salinity trends in the LS and ESS indicate that ocean circulation plays a dominate role in these areas, where in recent years freshwater has been diverted eastward along the coast, rather than northward toward the deep ocean.
Auroral particle acceleration by strong double layers: The upward current region
Authors: Ergun R. E. , Andersson L. , Main D. , Su Y.‐J. , Newman D. L. , Goldman M. V. , Carlson C. W. , Hull A. J. , McFadden J. P. , Mozer F. S.
Published: December 2004

Satellite observations have established that parallel electric fields of both upward and downward current regions of the aurora are supported, at least in part, by strong double layers. The purpose of this article is to examine the role of double layers in auroral electron acceleration using direct measurements of parallel electric fields and the accompanying particle distributions, electrostatic waves, and nonlinear structures; the concentration is on the upward current region. Direct observations of the ionospheric boundary of the auroral cavity suggest that a stationary, oblique double layer carries a substantial, albeit a minority fraction (∼10% to ∼50%) of the auroral potential. An order of magnitude density gradient results in an asymmetric electric field signature. Oblique double layers with amplitudes greater than 100 mV/m have been verified in ∼3% and may occur in up to 11% of auroral cavity crossings, so it is feasible that strong double layers are a principal acceleration mechanism. In this article we also present a second type of double layer that has a symmetric electric field signature and is seen inside of the auroral cavity. These structures are a possible signature of a midcavity or high‐altitude acceleration mechanism. Numerical solutions of the Vlasov‐Poisson equations support the possibility of midcavity double layers and indicate that trapped electrons can play an important role in the double‐layer structure.
Stress interaction between subduction earthquakes and forearc strike‐slip faults: Modeling and application to the northern Caribbean plate boundary
Authors: ten Brink Uri , Lin Jian
Published: December 2004

Strike‐slip faults in the forearc region of a subduction zone often present significant seismic hazard because of their proximity to population centers. We explore the interaction between thrust events on the subduction interface and strike‐slip faults within the forearc region using three‐dimensional models of static Coulomb stress change. Model results reveal that subduction earthquakes with slip vectors subparallel to the trench axis enhance the Coulomb stress on strike‐slip faults adjacent to the trench but reduce the stress on faults farther back in the forearc region. In contrast, subduction events with slip vectors perpendicular to the trench axis enhance the Coulomb stress on strike‐slip faults farther back in the forearc, while reducing the stress adjacent to the trench. A significant contribution to Coulomb stress increase on strike‐slip faults in the back region of the forearc comes from “unclamping” of the fault, i.e., reduction in normal stress due to thrust motion on the subduction interface. We argue that although Coulomb stress changes from individual subduction earthquakes are ephemeral, their cumulative effects on the pattern of lithosphere deformation in the forearc region are significant. We use the Coulomb stress models to explain the contrasting deformation pattern between two adjacent segments of the Caribbean subduction zone. Subduction earthquakes with slip vectors nearly perpendicular to the Caribbean trench axis is dominant in the Hispaniola segment, where the strike‐slip faults are more than 60 km inland from the trench. In contrast, subduction slip motion is nearly parallel to the Caribbean trench axis along the Puerto Rico segment, where the strike‐slip fault is less than 15 km from the trench. This observed jump from a strike‐slip fault close to the trench axis in the Puerto Rico segment to the inland faults in Hispaniola is explained by different distributions of Coulomb stress in the forearc region of the two segments, as a result of the change from the nearly trench parallel slip on the Puerto Rico subduction interface to the more perpendicular subduction slip beneath Hispaniola. The observations and modeling suggest that subduction‐induced strike‐slip seismic hazard to Puerto Rico may be smaller than previously assumed but the hazard to Hispaniola remains high.
Feedbacks of biotically induced radiative heating on upper‐ocean heat budget, circulation, and biological production in a coupled ecosystem‐circulation model
Authors: Oschlies Andreas
Published: December 2004

A coupled ecosystem‐circulation model of the North Atlantic Ocean is used to investigate the impact of radiative heating by biotically induced absorption of solar radiation on the ocean's heat budget, on water column stability and circulation, and on biological production itself. For fixed atmospheric conditions, the local sensitivity of the nonsolar heat flux to changes in sea surface temperature leads to a net cooling of the ocean by the biota at a rate of about 1 W m−2. As a result, simulated winter mixed‐layer depths are deeper by more than 100 m in parts of the subpolar gyre, whereas upper‐ocean stratification is enhanced in the tropics and subtropics, and coastal upwelling and associated nutrient supply are reduced by about 10% compared to a model run with optical properties of clear seawater. Simulated chlorophyll concentrations increase, indicating a positive feedback, only in subpolar regions that exhibit a pronounced phytoplankton spring bloom. Here biotically induced trapping of heat closer to the sea surface leads to a faster shoaling of the mixed layer and a more intense spring bloom in the model. On the basin average, simulated surface chlorophyll concentrations, however, decrease by 3%, constituting a weak negative feedback of 0.03 W m−2, when heating by biotic absorption of solar radiation is accounted for. These findings are based on the approximation of the atmosphere as a passive heat buffer and will have to be tested against results from fully coupled atmosphere‐ocean models with interactive marine biology.
Influence of periodontal disease on Th1/Th2‐type cytokines in saliva of HIV‐positive individuals
Authors: Vastardis S. , Leigh J. E. , Wozniak K. , Yukna R. , Fidel P. L
Published: December 2004

Cytokines present during immune responses have a tremendous influence on resistance/susceptibility to oral diseases including periodontal disease and oral opportunistic infections in the immunocompromised individual, as seen by altered Th cytokines in saliva with human immunodeficiency virus (HIV) disease progression and oropharyngeal candidiasis. This study was designed to evaluate whether the presence of severe periodontal disease has any influence on Th cytokines in saliva of HIV‐positive persons. For this, saliva from a cohort of HIV‐positive persons with mild or severe periodontitis was evaluated for Th cytokines. A dominant Th2‐type cytokine profile in saliva was validated in HIV‐positive subjects with considerable immune suppression, irrespective of periodontal disease status. However, no significant differences in concentrations of Th1‐ or Th2‐type cytokines in saliva were observed when stratified by periodontal status. Thus, the lack of salivary influences by periodontitis eliminates periodontal disease as a variable in interpretations regarding correlates of local cytokines during oral manifestations of HIV.
Evaluation of root canal microorganisms isolated from teeth with endodontic failure and their antimicrobial susceptibility
Authors: Pinheiro E. T. , Gomes B. P. F. A. , Ferraz C. C. R. , Teixeira F. B. , Zaia A. A. , Souza Filho F. J.
Published: December 2004

Studies of the microbiota from the canals of teeth with failure of endodontic therapy have revealed that it differs markedly from that of untreated necrotic dental pulps. This study aimed to evaluate the microbiota of 30 root‐filled teeth with persisting periapical lesions and to test the antibiotic susceptibility of the most prevalent species. Microbial samples, isolation and speciation were done using advanced microbiologic techniques for anaerobic species. A total of 55 bacterial species were isolated, 80% were gram‐positives and 58% facultative anaerobic microorganisms. The bacterial genera most frequently recovered were Enterococcus, Streptococcus, Peptostreptococcus and Actinomyces. Antibiotic sensitivity of Enterococcusfaecalis and Peptostreptococcus spp. was accomplished with the E‐test system. All species studied were susceptible to benzylpenicillin, amoxicillin, amoxicillin combined with clavulanate. However, 20% of the E.faecalis strains were resistant to erythromycin and 60% to azithromycin. It was concluded that microbial flora in canals after endodontic failure comprised predominantly facultative anaerobes and gram‐positive species. E.faecalis was the species most frequently isolated and showed erythromycin and azithromycin resistance among the isolates.
Influence of Enterococcus faecalis proteases and the collagen‐binding protein, Ace, on adhesion to dentin
Authors: Hubble T. S. , Hatton J. F. , Nallapareddy S. R. , Murray B. E. , Gillespie M. J.
Published: December 2004

Enterococcus faecalis is a pathogen that persists in medicated root canals. Here, we tested the hypothesis that the E. faecalis proteases, serine protease and gelatinase, and the collagen‐binding protein (Ace) contribute to adhesion to the root canal. Scanning electron microscopy was used to examine dentin binding by four E. faecalis strains: OG1RF, the wild type, and three mutant derivatives of OG1RF, TX5128, TX5243 and TX5256 deficient in serine protease and gelatinase, serine protease, and Ace, respectively. For each strain, 20 root halves were exposed to 3 × 109 to 5 × 109 cells/ml for 6 h, and 50 fields per root half were examined for adherent bacteria. Statistical analysis revealed that adherence of OG1RF was significantly greater than the mutant strains (P < 0.001), while significant differences were not detected between the protease mutants. The data indicate that serine protease and Ace aid E. faecalis binding to dentin, while the role of gelatinase is uncertain.
Changes in growth and polyglucose synthesis in response to fructose metabolism byFusobacterium nucleatumgrown in continuous culture
Authors: Zilm P. S. , Gully N. J. , Rogers A. H.
Published: December 2004

Fusobacterium nucleatum, grown in a chemically defined medium at μrel = 0.5, produced greater cell yields and undetectable levels of intracellular polyglucose (IP) when fructose was substituted for glucose. The utilisation and metabolism of fructose by growing cells was studied and the effect of the energy‐yielding amino acids, glutamate, serine, histidine and lysine on cell yield, IP synthesis and acidic end‐products was investigated. WhenF. nucleatumwas grown on elevated amino acid levels, IP was synthesised from fructose and amino acids were metabolised to lactate, acetate, butyrate and formate. Under these conditions, IP synthesis was associated with the cells being replete with amino acid‐derived energy; an observation supported by the absence of IP when the levels of (energy yielding) amino acids were reduced. Compared with fructose, glucose was less efficiently removed from the growth medium and produced less biomass and markedly lower levels of IP during energy‐limited growth.
The sortase of Streptococcus mutans mediates cell wall anchoring of a surface protein antigen
Authors: Igarashi T. , Asaga E. , Goto N.
Published: December 2004

Sortase has been shown to be a protease that catalyzes the cell wall anchoring of surface proteins containing an LPXTG motif in gram‐positive bacteria. In this study, we determined the complete nucleotide sequence of the sortase gene (srtA) of Streptococcus mutans and found a surface protein that was linked to the cell wall by the sortase. The results show that srtA gene of S. mutans consisted of 741 bp and encoded for a sortase protein of 246 amino acids with a molecular weight of 27 489. The deduced amino acid sequence of the S. mutans sortase was highly homologous (65–58%) to those of other Streptococcal species. In a S. mutans mutant lacking sortase, two surface proteins of 200 and 75 kDa were released to the culture supernatant. Western blot analysis with specific antiserum showed that the 200 kDa protein was a surface protein antigen designated PAc. These results suggest that the sortase catalyzes anchoring of the antigen PAc to the cell wall.
Molecular characterization of the presence of Eubacterium spp. and Streptococcus spp. in endodontic infections
Authors: Fouad A. F. , Kum K.‐Y. , Clawson M. L. , Barry J. , Abenoja C. , Zhu Q. , Caimano M. , Radolf J. D.
Published: December 2004

Eubacterium spp. and Streptococcus spp. are virulent, commonly identified microorganisms in endodontic infections. The purpose of this study was to use molecular methods to identify these organisms in 22 infected root canals that include eight cases with preoperative clinical symptoms and five cases with a history of diabetes mellitus. The presence of Streptococcus spp. and Eubacterium spp. was examined using two sets of PCR primers specific with multiple species within the respective genera. Positive specimens had their PCR products sequenced and phylogenetically analyzed to identify the specific species. Sixteen specimens (73%) contained Eubacterium spp. and nine (41%) were positive for Streptococcus spp. Eubacterium infirmum was the most prevalent Eubacterium sp. This organism was significantly associated with a history of diabetes (OR = 9.6; P = 0.04). Streptococcus anginosus was the most common Streptococcus sp., but neither it nor any of the other streptococci were significantly associated with the clinical parameters evaluated.
Markers of inflammation and bronchial reactivity in children with asthma, exposed to animal dander in school dust
Authors: LÃ¶nnkvist K. , Halldén G. , Dahlén S. E. , Enander I. , van Hage‐Hamsten M. , Kumlin M. , Hedlin G.
Published: December 2004

Several studies have confirmed the presence of animal dander allergens in school dust but the effect of this indirect animal exposure on health has not been evaluated. In this study we investigated bronchial reactivity and markers of eosinophil activity and inflammation during two separate weeks of school in 10 children with mild asthma and a positive skin prick test to cat and dog. At the beginning and the end of the first week the children underwent bronchial challenges with methacholine, and at the beginning and the end of the second week they underwent nasal lavages (NAL) and induced sputum samplings. Blood and urine samples for analysis of inflammatory markers were obtained before and after both school weeks. Peak expiratory flow (PEF) and symptoms of asthma and allergy were recorded daily, and spirometry was performed on each visit. The exposure to animal dander allergens was estimated from dust samples obtained in the subjects’ schools and homes. Bronchial sensitivity to methacholine increased in the week when this was measured. The proportion of eosinophils in peripheral blood, and urinary eosinophil protein X (EPX), decreased in both weeks. There was a trend towards an increase of eosinophil peroxidase (EPO) and myeloperoxidase (MPO) in sputum in the week when these proteins were measured. The concentrations of cat (Fel d1) and dog (Can f1) allergens were higher in dust collected in schools than in homes. Our results show that in children with mild asthma and animal dander allergy, there is a significantly increased bronchial sensitivity to methacholine after one school week. There is also a significant decrease in the number of circulating eosinophils and a trend towards an increase of sputum EPO, which could correlate with the early phase of eosinophil recruitment to the lungs. These effects may be related to the continuous exposure to animal allergens in school dust.
Wheezing in school children is not always asthma
Authors: Nystad W. , Stensrud T. , Rijcken B. , Hagen J. , Magnus P. , Carlsen K. ‐H.
Published: December 2004

Our objective was to study whether children with reported asthma differed from children with wheeze but without asthma, and from children with neither asthma nor wheeze, regarding lung function, bronchial hyper‐responsiveness (BHR) using methacholine inhalation, exercise‐induced bronchoconstriction (EIB), and skin prick test (SPT) reactivity. School children (n=2188), enrolled in a survey of asthma, were classified into three mutually exclusive groups by parental report of: asthma, wheeze, and no asthma/no wheeze. A random sample of 80 children in each group was tested (n=240). Among asthmatics, 68% (95% confidence interval (CI), 57–79) had a BHR (measured as PD20 forced expiratory volume in 1 s (FEV1) ≤ 8.16 μmol using methacholine) compared to 31% (CI 20–42%) and 30% (CI 19–40%) in the wheeze and no asthma/no wheeze groups. The dose–response slope (DRS) confirmed the PD20 data and distinguished equally between groups. EIB (≥10% fall in FEV1) was more frequent (40%, CI 29–52%) among asthmatics than among children with wheeze (12%, CI 4–19%) and no asthma/no wheeze (7%, CI 1–13%). The prevalence of at least one positive SPT was twice as high in the asthma group (58%, 47–69%) than in the wheeze (27%, CI 16–37%) and the no asthma/no wheeze (25%, 15–35%) groups. These results indicate that children with asthma differ from children with wheeze and children with no asthma/no wheeze regarding lung function, BHR, EIB, and SPT reactivity. Children with wheeze are more similar to children with no asthma/no wheeze with respect to these parameters.
Macrophage inflammatory protein‐1α and RANTES are present in nasal secretions during ongoing upper respiratory tract infection
Authors: Bonville C. A. , Rosenberg H. F. , Domachowske J. B.
Published: December 2004

Marcophage inflammatory protein‐1α (MIP‐1α) and RANTES (regulated upon activation, normal T‐cell expressed and secreted) were measured by enzyme‐linked immunosorbent assay (ELISA) from virus‐infected respiratory cell culture supernatants and from 100 nasal wash samples obtained from patients aged 8 d to 10 yr. The results of the nasal wash samples were analyzed in relation to the etiology of the viral infection. In vitro, respiratory syncytial virus (RSV) induced the production of MIP‐1α, while both RSV and adenovirus were associated with the production of RANTES. Both MIP‐1α and RANTES were detected in nasopharyngeal secretions from pediatric patients with acute upper respiratory tract RSV, adenovirus, influenza, and parainfluenza virus infection (p<0.001 by Fisher’s exact test). As both of these chemokines have potent effects on the recruitment and degranulation of eosinophils and basophils, further understanding of their role in upper respiratory tract infections may provide valuble insights into the immunopathogenesis of respiratory viral infections.
Exposure to peanuts in utero and in infancy and the development of sensitization to peanut allergens in young children
Authors: Frank L. , Marian A. , Visser M. , Weinberg E. , Potter P. C.
Published: December 2004

This study attempted to determine the underlying factors that may influence the development of peanut sensitization in young children in South Africa. One of our objectives was to ascertain whether the consumption of peanuts or peanut‐containing foods during pregnancy and lactation by mothers from atopic families impacted upon the development of an allergic response to peanuts in the child. Forty‐three children between the ages of 0 and 3 yr participated in this study. There were 25 peanut‐sensitized subjects and 18 control subjects (children sensitized to milk and/or egg, but not to peanuts). A significant association was found between peanut sensitization and sensitivity to soya (p=0.0002), wheat (p=0.03), and cod fish. We found that mothers who consumed peanuts more than once a week during pregnancy were more likely to have a peanut‐allergic child than mothers who consumed peanuts less than once a week (odds ratio=3.97, 98% confidence interval 0.73–24). Peanuts or peanut butter was introduced into the child’s diet from a significantly younger age in the peanut‐allergic subjects (p<0.03). There was a positive correlation in the peanut‐allergic subjects between age of introduction of peanuts and age at the onset of symptoms (r = 0.63). Exclusive breast feeding did not protect against the development of peanut sensitization. Peanut allergy is associated with an increased risk of sensitization to other foods. It is more likely to occur if mothers eat peanuts more frequently during pregnancy and introduce it early to the infant’s diet. These features highlight potentially avoidable factors that might prevent sensitization.
Study on the Prevention of Allergy in Children in Europe (SPACE): Allergic sensitization at 1 year of age in a controlled trial of allergen avoidance from birth
Authors: Halmerbauer Gerhard , Gartner Christian , Schierl Michael , Arshad Hassan , Dean Tara , Koller Dieter Y. , Karmaus Wilfried , Kuehr Joachim , Forster Johannes , Urbanek Radvan , Frischer Thomas ,   the SPACE Collaborative Study Team
Published: December 2004

Several studies have demonstrated that early intervention may modulate the natural course of atopic disease. The objective of this study was to prevent sensitization to house dust mite and food allergens, as well as development of atopic symptoms, during infancy. To achieve this we employed the combination of an educational package with the use of mite allergen‐impermeable mattress encasings. A multi‐center European, population‐based, randomized controlled study of children at increased atopic risk [study on the prevention of Allergy in Children in Europe (SPACE)] was performed in five countries (Austria, Germany, Greece, Great Britain, Lithuania) and included three cohorts of schoolchildren, toddlers and newborns. We report on the newborn cohort. A total of 696 newborns were included in Austria, Great Britain and Germany. Inclusion criteria were a positive history of parental allergy and a positive skin‐prick test or specific immunoglobulin E (IgE) of ≥ 1.43 kU/l against at least one out of a panel of common aeroallergens in one or both parents. At 1 year of age the overall sensitization rate against the tested allergens [dust mite allergens: Dermatophagoides pteronyssinus and D. farinae (Der p and Der f, respectively)] and food allergens (egg, milk) in the prophylactic group was 6.21% vs. 10.67% in the control group. The prevalence of sensitization against Der p was 1.86% in the prophylactic group vs. 5% in the control group. In conclusion, we demonstrated, in a group of newborns at risk for atopic diseases, that the sensitization rate to a panel of aero‐ and food allergens could be effectively decreased through the use of impermeable mattress encasings and the implementation of preventive measures that were easy to perform.
The role of craniofacial growth in leptin deficient (ob/ob) mice
Authors: Yagasaki Y. , Yamaguchi T. , Watahiki J. , Konishi M. , Katoh H. , Maki K.
Published: December 2004

Structured Abstract

Authors – Yagasaki Y, Yamaguchi T, Watahiki J, Konishi M, Katoh H, Maki K.

Objectives – To elucidate the role of leptin on maxillo‐facial morphological growth using hereditary obesity model ob/ob mice, and to examine the presence of the leptin receptor gene expression in the mouse condylar head cartilage.

Design – Leptin was intraperitoneally administered once a day in 10 C57BL/6J (lean) and 10 C57BL/6J‐ob (ob/ob) mice (leptin administration group), and phosphate‐buffered saline (PBS) in 10 lean and 10 ob/ob mice (PBS administration group), between the fifth and 11th week after birth. The amount of fat, the body amount without fat, the rate of body fat, and the width of the condylar cervical area were measured during the11th week, and roentgenographic cephalometric analysis was performed at the fifth, eighth, and 11th week. Furthermore, the condylar head cartilage in C57BL/6J mice was stereoscopically excised to extract total RNA, and RT‐PCR method was performed regarding the leptin receptor gene.

Results – The body fat amount in ob/ob mice with leptin production insufficiency was greater than that in lean mice, and significant differences were noted in every measurement item regarding maxillo‐facial morphology. Recovery of bone length was noted in ob/ob mice by administering leptin. Furthermore, the expression of the leptin receptor gene in the condylar head cartilage was confirmed.

Conclusion – Exogenous leptin administration leads to significant increases in craniofacial dimensions; and leptin receptors are expressed in mandibular condylar cartilage. These results indicate an important role for leptin in craniofacial growth and morphology. We speculate that leptin's direct peripheral effect on bone and cartilage is closely involved in this role.
Using Self‐Reported Data to Predict Expenditures for the Health Care of Older People
Authors: Pacala James T. , Boult Chad , Urdangarin Cristina , McCaffrey David
Published: December 2004

OBJECTIVES: To create and test a method for using self‐reported data to predict future expenditures for the health care of older people.

DESIGN: A two‐stage regression model of the relationship between self‐reported data and Medicare expenditures during the following year was constructed from a randomly selected (derivation) half of a cohort of fee‐for‐service Medicare beneficiaries. For the other (validation) half of the cohort, two sets of predictions of 12‐month Medicare expenditures were generated, one using the new two‐stage model and the other using the principal inpatient diagnostic cost group (PIP‐DCG) method now used to risk‐adjust capitation payments to Medicare + Choice health plans. Both sets of predictions were compared with Medicare's actual 12‐month expenditures for the validation cohort.

SETTING: Ramsey County, Minnesota.

PARTICIPANTS: Community‐dwelling Medicare beneficiaries aged 70 and older (N = 13,682) who responded to a mailed survey.

MEASUREMENTS: Predicted‐to‐observed ratio (PTOR) of Medicare expenditures.

RESULTS: For the validation cohort, Medicare's actual 12‐month expenditures totaled $26.5 million. The two‐stage model predicted Medicare expenditures of $26.4 million (PTOR = 1.00); the PIP‐DCG method predicted $31.2 million (PTOR = 1.18). Within subpopulations of healthy and ill beneficiaries, the two‐stage model's predictions remained considerably more accurate than the PIP‐DCG predictions.

CONCLUSION: Self‐reported data may predict future Medicare expenditures more accurately than administrative data about beneficiaries' demographic characteristics, and previous hospitalizations.
Functional Outcomes of Excessive Daytime Sleepiness in Older Adults
Authors: Gooneratne Nalaka S. , Weaver Terri E. , Cater Jacqueline R. , Pack Frances M. , Arner Heidi M. , Greenberg Andra S. , Pack Allan I.
Published: December 2004

OBJECTIVES: To describe the effect of self‐reported excessive daytime sleepiness (EDS) on functional outcomes.

DESIGN: Case‐control study designed to examine differences in functional status between cases (with daytime sleepiness) and controls (no daytime sleepiness) with regard to demographic factors, general health, sleep history, and medications.

SETTING: Retirement communities in southeastern Pennsylvania, Delaware, and New Jersey.

PARTICIPANTS: Seventy‐six nondepressed, nondemented adults, aged 65 and older, were cases (had daytime sleepiness) and 38 were controls (had no daytime sleepiness).

MEASUREMENTS: Standardized questionnaires to assess disease‐specific functional status (Functional Outcomes of Sleepiness Questionnaire (FOSQ) and Epworth Sleepiness Scale (ESS)), depression (Geriatric Depression Scale‐Short Form and the Center for Epidemiologic Studies‐Depression Scale), dementia (Short Blessed Test), demographic factors, current medical history, and sleep complaints.

RESULTS: There was a significant difference in functional status between sleepy cases and nonsleepy controls. Sleepiness had a moderate to large negative effect (effect size range from 0.59 to 0.83, P < .005) on the following functional domains of the FOSQ: social outcome, general productivity, vigilance, activity level, and global assessment of functional status. Correlation between ESS and FOSQ subscales were −0.31 to −0.67, P < .05. Examination of cases with daytime sleepiness revealed increased functional impairment in individuals with more than three medical conditions or those taking more than four medications (P < .001 and P = .03, respectively).

CONCLUSION: Daytime sleepiness is associated with functional impairments in a broad range of activities. The decrease in daily functioning noted in the sleepy subjects has implications for deconditioning and related comorbidity. These findings suggest that exploration of daytime sleepiness should be part of the ongoing assessment of the elderly, particularly those with multiple medical conditions.
Gastrointestinal Disease Control After Histamine2‐Receptor Antagonist Dose Modification for Renal Impairment in Frail Chronically Ill Elderly Patients
Authors: Lackner Thomas E. , Heard Tom , Glunz Samantha , Gann Nicole , Babington Maude , Malone Daniel C.
Published: December 2004

OBJECTIVES: To determine whether histamine2‐receptor antagonist (H2RA) dose modified for renal impairment affects gastrointestinal (GI) disease control.

DESIGN: Concurrent medical record review.

SETTING: One hundred forty‐six nursing facilities throughout the United States.

PARTICIPANTS: Three hundred thirty‐six patients aged 65 and older receiving H2RAs for GI disorders.

INTERVENTION: H2RA dose modified for renal impairment or no dose change.

MEASUREMENTS: Disease control (no H2RA dose increase for 6 months or longer, additional GI medication, hospitalizations, emergency room visits, and unscheduled physician visits for GI symptoms) was evaluated using chart review at 3, 6, 9, and 12 months in nursing home patients aged 65 and older with H2RA dose modified for decreased creatinine clearance (ClCr) according to manufacturer.

RESULTS: Three hundred thirty‐six patients, mean age ± standard deviation 85.9 ± 7.9, with mean ClCr of 33.6 ± 10.4 mL/min, were recommended to receive lower H2RA doses based upon estimated renal function. Patients were analyzed in two groups: H2RA dose reduced (Group 1) and dose reduction not adopted or implemented (Group 2). There was no difference in baseline characteristics (age, weight, ClCr, or starting H2RA dose and indication) between the two groups. One hundred ninety‐eight patients in Group 1 were taking 195.5 ± 71.0 mg per day of nizatidine or equivalent, compared with 183.7 ± 66.6 mg for 138 patients in Group 2. For patients with 90 days of follow‐up, the mean H2RA dose in Group 1 was 100.2 ± 44.3 mg, compared with 187.8 ± 69.9 for Group 2 (P < .0001) The mean decrease in daily dose for Groups 1 and 2 after 365 days were 98.9 ± 72.9 mg and 22.2 ± 68.2 mg, respectively (P < .0001). Except for more physician visits in Group 2, disease control was similar for all groups. Major and minor GI bleeding events were similar across both groups and over time. The 12‐month mortality rate was 12.1% and 21.7% for Groups 1 and 2, respectively. This difference was statistically significant (P = .02).

CONCLUSION: The findings suggest that the dose of H2RAs may be decreased based upon renal function in frail elderly patients without compromising GI disease control.
Direct measurement of hepatic tissue hypoxia by using a novel tcpO2/pCO2 monitoring system in comparison with near‐infrared spectroscopy
Authors: Yang Wenxuan , Hafez Tariq , Thompson Cecil S. , Mikhailidis Dimitri P. , Davidson Brain R. , Winslet Marc C. , Seifalian Alexander M.
Published: December 2004

Abstract: Background/Aims: Hepatic hypoxia occurs during liver surgery and transplantation and it may also appear within liver tumours, correlating with prognosis and efficacy of the treatment. The present study measured liver tissue hypoxia by directly using near‐infrared spectroscopy (NIRS) and a novel tcpO2/pCO2 monitoring system. Methods: Graded hypoxia was achieved in a rabbit model by a stepwise reduction of the fraction of inspired oxygen (FiO2) from 0.3 to 0.0. Animals were allowed to recover from hypoxia at FiO2 of 3.0 indicated by normalised arterial blood gas values. Hepatic tissue oxyhaemoglobin (HbO2), deoxyhaemoglobin (Hb), cytochrome oxidase (Cyt Ox), oxygen partial pressure (pO2) and carbon dioxide partial pressure (pCO2) were measured continuously with the help of NIRS and a Clark‐type surface tcpO2/pCO2 monitoring system, throughout the period of hypoxaemia.

Results: There was an immediate reduction in hepatic HbO2 with hypoxia and a simultaneous increase in hepatic Hb. Similarly, hepatic tissue pO2 decreased significantly but tissue pCO2 remained unchanged until the FiO2 was below 0.1. Hepatic HbO2 showed a positive correlation with tissue pO2 (r = 0.53, P < 0.001). Hepatic Hb showed a negative correlation with tissue pO2 (r = 0.47, P < 0.001). Hepatic Cyt Ox decreased significantly with an FiO2 of 0.1 or less and showed a positive correlation with hepatic tissue pO2 (r = 0.64, P < 0.001). A significant correlation was found between hepatic tissue pO2 and arterial blood pO2 (r = 0.44, P < 0.001). Arterial blood pCO2 also correlated with hepatic tissue pCO2 (r = 0.53, P < 0.001) measured by the tcpO2/pCO2 monitoring system.

Conclusion: The data from the present study suggest that, like NIRS, the tcpO2/pCO2 monitoring system can be reliably used for the direct monitoring of hepatic tissue oxygenation in vivo.
Aberrant p16INK4A RNA transcripts expressed in hepatocellular carcinoma cell lines regulate pRb phosphorylation by binding with CDK4, resulting in delayed cell cycle progression
Authors: Cho Jae‐We , Jeong Yong‐Wook , Han Seung‐Wook , Park Jae‐Bok , Jang Byeong‐Churl , Baek Won‐Ki , Kwon Taeg Kyu , Park Jong‐Wook , Kim Sang‐Pyo , Suh Min‐Ho , Suh Seong‐Il
Published: December 2004

Abstract: The inactivation of the p16INK4A (p16) gene by promoter hypermethylation has been reported in many human cancers. We previously reported that aberrant p16 RNA transcripts are expressed in hepatocellular carcinoma (HCC) cell lines having hypermethylated p16 promoters. In this study, we investigated the functional roles of aberrant p16 RNA transcripts in HCC cells to elucidate molecular events underlying hepatocarcinogenesis. The aberrant p16 RNA transcripts encoded key peptides (amino acids 84–103) involved in binding with cyclin‐dependent kinase (CDK) 4. GST‐aberrant p16 fusion proteins were found to interact with endogenous CDK4 in vitro. Furthermore, overexpression of these aberrant p16 RNA transcripts resulted in decreased cell proliferation rate, enlargement of cell shape and reduced level of hyperphosphorylated forms of pRb. Overall, our results suggest that the aberrant p16 RNA transcripts have functions similar to those of wild type p16 in controlling cell cycle.