bluuebunny/crossref_metadata_2025_split huggingface dataset:
Neuroimaging and Neurophysiology of Periodic Lateralized Epileptiform Discharges: Observations and Hypotheses
Authors: Kalamangalam Giridhar P. , Diehl Beate , Burgess Richard C. 
Published: March 2007

Summary:  Purpose: We assessed neuroimaging lesion type and distribution in patients with periodic lateralized epileptiform discharges (PLEDs), with a view to identifying electrographic differences between PLEDs associated with differing lesion locations. Our observations led us to consider a conceptual synthesis between PLEDs and periodic complexes (PCs). Methods: Retrospective review of acute neuroimaging results (CT/MRI) on patients identified to have EEG PLEDs, for the period 1999–2003 (n = 106). Blinded classification of original EEG recordings. Results: Neuroimaging abnormalities were classified as acute or chronic cortical, or acute or chronic subcortical. Seven out of 106 scans were classified nonlesional. Overall ∼70% of scans had cortical abnormalities, whether acute or chronic; ∼23% had subcortical abnormalities. “Cortical” PLEDs were significantly longer in duration (p < 0.05) and more variable in morphology (p < 0.01) than “subcortical” PLEDs. Conclusions: Structural brain disease commonly, but not invariably, underlies PLEDs; lesion type is spatiotemporally variable. Cortical and subcortical PLEDs have distinct EEG signatures. There is evidence that these may relate to mechanisms for other pathological large‐scale oscillatory brain synchronies (e.g., PCs).
Bidirectional Alterations of Hippocampal Cannabinoid 1 Receptors and Their Endogenous Ligands in a Rat Model of Alcohol Withdrawal and Dependence
Authors: Mitrirattanakul Somsak , López‐Valdés Héctor E. , Liang Jing , Matsuka Yoshizo , Mackie Ken , Faull Kym F. , Spigelman Igor 
Published: March 2007

Background: The hippocampus is strongly implicated in memory processes and contains high concentrations of both cannabinoid receptors and their endogenous ligands. Chronic alcohol consumption impairs a variety of cognitive and performance tasks, including memory and learning. As the activation of cannabinoid receptors by their endogenous ligands modulates hippocampal neurotransmission, we hypothesized that the impaired memory and learning in alcoholism may be due to alterations in the hippocampal endocannabinoid system.Methods: We used the rat chronic intermittent ethanol (CIE) model for alcohol withdrawal and dependence which involves intermittent episodes of ethanol intoxication (60 doses) and withdrawal (approximating binge drinking episodes in humans). We measured the levels of cannabinoid 1 receptor (CB1R) protein (Western blot using a C‐terminal–directed antibody), CB1R mRNA (real‐time RT‐PCR), CB1R localization (immunocytochemistry), tissue levels of the endocannabinoids N‐arachidonoylethanolamine/anandamide (AEA) and 2‐arachidonoylglycerol (2‐AG), and function (patch‐clamp recordings of depolarization‐induced suppression of inhibition (DSI), as well as effects of CB1R agonist WIN 55,212‐2 on inhibitory currents) in the hippocampus of CIE rats and their saline‐treated controls.Results: Results were obtained in saline and CIE‐treated rats after 2 and 40 days of withdrawal (DW) from their respective treatments. In 2 DW CIE rats, CB1R mRNA and protein levels were decreased by 27% (p<0.05) compared with saline controls. Surprisingly, in 40 DW CIE rats, CB1R mRNA increased by 100% and protein increased by 21%, confirmed by immunohistochemistry. Hippocampal [2‐AG] increased in both 2 and 40 DW CIE rats; [AEA] increased only at 40 DW. Hippocampal DSI of CIE rats was significantly reduced at 2 DW but not at 40 DW. The CB1R agonist WIN 55,212‐2 (0.5 μM) produced a significantly greater decrease in the frequency of spontaneous inhibitory currents from saline‐treated rats compared with CIE rats at 2 DW, but not at 40 DW.Conclusions: These data demonstrate that CIE treatment and withdrawal transiently down‐regulates hippocampal CB1Rs followed by a long‐term up‐regulation, including increased levels of endogenous cannabinoids. These findings are consistent with our hypothesis and suggest that long‐term up‐regulation of hippocampal CB1Rs may contribute to the long‐term cognitive impairments in alcoholism. The data further suggest that the effectiveness of CB1R blockade in decreasing alcohol consumption may be greater after protracted abstinence from alcohol.
Concentration-Dependent Synergy and Antagonism within a Triple Antifungal Drug Combination againstAspergillusSpecies: Analysis by a New Response Surface Model
Authors: Meletiadis Joseph , Stergiopoulou Theodouli , O'Shaughnessy Elizabeth M. , Peter Joanne , Walsh Thomas J. 
Published: March 2007

ABSTRACTTriple antifungal combinations are used against refractory invasive aspergillosis without an adequate understanding of their pharmacodynamic interactions. We initially studied the in vitro triple combination of voriconazole, amphotericin B, and caspofungin againstAspergillus fumigatus,A. flavus, andA. terreusby a spectrophotometric microdilution broth method after 48 h of incubation. We then analyzed these results with a recently described nonlinear mixture response surfaceEmax-based model modified to assess pharmacodynamic interactions at various growth levels. The new model allows flexibility in all four parameters of theEmaxmodel and is able to describe complex pharmacodynamic interactions. Concentration-dependent pharmacodynamic interactions were found within the triple antifungal combination. At the 50% growth level, synergy (median interaction indices of 0.43 to 0.82) was observed at low concentrations of voriconazole (<0.03 mg/liter) and amphotericin B (≤0.20 mg/liter) and at intermediate concentrations of caspofungin (0.95 to 14.88 mg/liter), whereas antagonism (median interaction indices of 1.17 to 1.80) was found at higher concentrations of voriconazole and amphotericin B. Ternary plot and interaction surface analysis further revealed the complexity of these concentration-dependent interactions. With increasing concentrations of amphotericin B, the synergistic interactions of voriconazole-caspofungin double combination decreased while the antagonistic interactions increased. A similar effect was observed when voriconazole was added to the double combination of amphotericin B and caspofungin. In conclusion, the new nonlinear mixture-amount response surface modeling of the triple antifungal combination demonstrated a net antagonism or synergy againstAspergillusspecies depending upon drug concentrations and species.
STABILITY OF THE kTH ORDER LYNESS' EQUATION WITH A PERIOD-k COEFFICIENT
Authors: JANOWSKI E. J. , KULENOVIĆ M. R. S. , NURKANOVIĆ Z. 
Published: March 2007

We first investigate the Lyapunov stability of the period-three solution of Todd's equation with a period-three coefficient: [Formula: see text] where [Formula: see text] α,β, and γ positive. Then for k = 2,3,… we extend our stability result to the k-order equation, [Formula: see text] where pn is a periodic coefficient of period k with positive real values and x-k+1,…,x-1, x0 ∈ (0, ∞).
A Study of the Response of Deep Tropical Clouds to Large-Scale Thermodynamic Forcings. Part II: Sensitivities to Microphysics, Radiation, and Surface Fluxes
Authors: Johnson D. E. , Tao W-K. , Simpson J. 
Published: March 2007

Abstract
The Goddard Cumulus Ensemble (GCE) model is used to examine the sensitivities of multiday 2D simulations of deep tropical convection to surface fluxes, interactive radiation, and ice microphysical processes. The simulations incorporate large-scale temperature, moisture, and momentum forcings, from the Tropical Ocean Global Atmosphere Coupled Ocean–Atmosphere Response Experiment (TOGA COARE) for the period 19–27 December 1992.
This study shows that, when surface fluxes are eliminated, the mean simulated atmosphere is much cooler and drier, convection and CAPE are much weaker, precipitation is less, and low-level to midlevel cloudiness is much greater. Surface fluxes using the TOGA COARE flux algorithm are weaker than with the aerodynamic formulation, but closer to the observed fluxes. In addition, trends similar to those noted above for the case without surface fluxes are produced for the TOGA COARE flux case, albeit to a much lesser extent. The elimination of shortwave and longwave radiation is found to have only minimal effects on the mean thermodynamics, convection, and precipitation. However, exclusion of radiation in the model does have a significant impact on cloud temperatures and structure above 200 mb.
The removal of ice microphysical processes produces major changes in the structure of the clouds. Much of the liquid water is transported to the upper levels of the troposphere and evaporates, resulting in less mean total surface precipitation. The precipitation primarily occurs in regions of narrow, but intense, convective rainfall bands. The elimination of melting processes (diabatic cooling and conversions to rain) leads to greater (ice) hydrometeor mass below the 0°C level and reduced latent cooling. This, along with weaker vertical cloud mass fluxes, produces a much warmer and moister boundary layer, and a greater mean CAPE. Finally, the elimination of the graupel species has only a small impact on mean total precipitation, thermodynamics, and dynamics of the simulation, but does produce much greater snow mass just above the melting layer.
Toward Understanding the Dynamical Origin of Atmospheric Regime Behavior in a Baroclinic Model
Authors: Sempf Mario , Dethloff Klaus , Handorf Dörthe , Kurgansky Michael V. 
Published: March 2007

Abstract
Dynamical mechanisms of atmospheric regime behavior are investigated in the context of a quasigeostrophic three-level T21 model of the wintertime atmospheric circulation over the Northern Hemisphere. The model, driven by realistic orography and using a thermal forcing determined by a newly developed tuning procedure, is shown to possess a reasonable climatology and to simulate the Arctic Oscillation quite realistically. It exhibits pronounced internally generated interannual and decadal variability and, in particular, circulation regimes that agree fairly well with observed ones. Two known hypotheses about the origin of regime behavior, as it occurs in the model herein are addressed: (i) multiple equilibria and (ii) chaotic itinerancy between attractor ruins. The first hypothesis is falsified at very high probability, while the second is likely to be true.
Evolution of Water Vapor Concentrations and Stratospheric Age of Air in Coupled Chemistry-Climate Model Simulations
Authors: Austin John , Wilson John , Li Feng , Vömel Holger 
Published: March 2007

Abstract
Stratospheric water vapor concentrations and age of air are investigated in an ensemble of coupled chemistry-climate model simulations covering the period from 1960 to 2005. Observed greenhouse gas concentrations, halogen concentrations, aerosol amounts, and sea surface temperatures are all specified in the model as time-varying fields. The results are compared with two experiments (time-slice runs) with constant forcings for the years 1960 and 2000, in which the sea surface temperatures are set to the same climatological values, aerosol concentrations are fixed at background levels, while greenhouse gas and halogen concentrations are set to the values for the relevant years.
The time-slice runs indicate an increase in stratospheric water vapor from 1960 to 2000 due primarily to methane oxidation. The age of air is found to be significantly less in the year 2000 run than the 1960 run. The transient runs from 1960 to 2005 indicate broadly similar results: an increase in water vapor and a decrease in age of air. However, the results do not change gradually. The age of air decreases significantly only after about 1975, corresponding to the period of ozone reduction. The age of air is related to tropical upwelling, which determines the transport of methane into the stratosphere. Oxidation of increased methane from enhanced tropical upwelling results in higher water vapor amounts. In the model simulations, the rate of increase of stratospheric water vapor during the period of enhanced upwelling is up to twice the long-term mean. The concentration of stratospheric water vapor also increases following volcanic eruptions during the simulations.
Intrinsic versus Forced Variation in Coupled Climate Model Simulations over the Arctic during the Twentieth Century*
Authors: Wang Muyin , Overland James E. , Kattsov Vladimir , Walsh John E. , Zhang Xiangdong , Pavlova Tatyana 
Published: March 2007

Abstract
There were two major multiyear, Arctic-wide (60°–90°N) warm anomalies (&gt;0.7°C) in land surface air temperature (LSAT) during the twentieth century, between 1920 and 1950 and again at the end of the century after 1979. Reproducing this decadal and longer variability in coupled general circulation models (GCMs) is a critical test for understanding processes in the Arctic climate system and increasing the confidence in the Intergovernmental Panel on Climate Change (IPCC) model projections. This study evaluated 63 realizations generated by 20 coupled GCMs made available for the IPCC Fourth Assessment for their twentieth-century climate in coupled models (20C3M) and corresponding control runs (PIcntrl). Warm anomalies in the Arctic during the last two decades are reproduced by all ensemble members, with considerable variability in amplitude among models. In contrast, only eight models generated warm anomaly amplitude of at least two-thirds of the observed midcentury warm event in at least one realization, but not its timing. The durations of the midcentury warm events in all the models are decadal, while that of the observed was interdecadal. The variance of the control runs in nine models was comparable with the variance in the observations. The random timing of midcentury warm anomalies in 20C3M simulations and the similar variance of the control runs in about half of the models suggest that the observed midcentury warm period is consistent with intrinsic climate variability. Five models were considered to compare somewhat favorably to Arctic observations in both matching the variance of the observed temperature record in their control runs and representing the decadal mean temperature anomaly amplitude in their 20C3M simulations. Seven additional models could be given further consideration. Results support selecting a subset of GCMs when making predictions for future climate by using performance criteria based on comparison with retrospective data.
Potential Impact of the Eurasian Boreal Forest on North Pacific Climate Variability*
Authors: Notaro Michael , Liu Zhengyu 
Published: March 2007

Abstract
The authors demonstrate that variability in vegetation cover can potentially influence oceanic variability through the atmospheric bridge. Experiments aimed at isolating the impact of variability in forest cover along the poleward side of the Asian boreal forest on North Pacific SSTs are performed using the fully coupled model, Fast Ocean Atmosphere Model–Lund Potsdam Jena (FOAM-LPJ), with dynamic atmosphere, ocean, and vegetation. The northern edge of the simulated Asian boreal forest is characterized by substantial variability in annual forest cover, with an east–west dipole pattern marking its first EOF mode. Simulations in which vegetation cover is allowed to vary over north/central Russia exhibit statistically significant greater SST variance over the Kuroshio Extension. Anomalously high forest cover over North Asia supports a lower surface albedo with higher temperatures and lower sea level pressure, leading to a reduction in cold advection into northern China and in turn a decrease in cold air transport into the Kuroshio Extension region. Variability in the large-scale circulation pattern is indirectly impacted by the aforementioned vegetation feedback, including the enhancement in upper-level jet wind variability along the north–south flanks of the East Asian jet stream.
Impact Assessment of Satellite-Derived Leaf Area Index Datasets Using a General Circulation Model
Authors: Kang Hyun-Suk , Xue Yongkang , Collatz G. James 
Published: March 2007

Abstract
This study assesses the impact of two different remote sensing–derived leaf area index (RSLAI) datasets retrieved from the same source (i.e., Advanced Very High Resolution Radiometer measurements) on a general circulation model’s (GCM) seasonal climate simulations as well as the mechanisms that lead to the improvement in simulations over several regions. Based on the analysis of these two RSLAI datasets for 17 yr from 1982 to 1998, their spatial distribution patterns and characteristics are discussed. Despite some disagreements in the RSLAI magnitudes and the temporal variability between these two datasets over some areas, their effects on the simulation of near-surface climate and the regions with significant impact are generally similar to each other. Major disagreements in the simulated climate appear in a few limited regions.
The GCM experiment using the RSLAI and other satellite-derived land surface products showed substantial improvements in the near-surface climate in the East Asian and West African summer monsoon areas and boreal forests of North America compared to the control experiment that used LAI extrapolated from limited ground surveys. For the East Asia and northwest U.S. regions, the major role of RSLAI changes is in partitioning the net radiative energy into latent and sensible heat fluxes, which results in discernable warming and decrease of precipitation due to the smaller RSLAI values compared to the control. Meanwhile, for the West African semiarid regions, where the LAI difference between RSLAI and control experiments is negligible, the decrease in surface albedo caused by the high vegetation cover fraction in the satellite-derived dataset plays an important role in altering local circulation that produces a positive feedback in land/atmosphere interaction.
Ocean Model Diagnosis of Low-Frequency Climate Variability in the South Atlantic Region
Authors: Colberg Frank , Reason C. J. C. 
Published: March 2007

Abstract
South Atlantic Ocean variability is investigated by means of an ocean general circulation model (ORCA2), forced with the NCEP–NCAR reanalyses for the 1948–99 period. A rotated EOF analysis of the mixed layer temperature suggests a breakdown of the South Atlantic into the following four subdomains, with characteristic spatial and temporal scales: (a) the tropical Atlantic, with mainly interannual fluctuations; (b) the northeastern subtropics, with variability on an interannual to decadal scale; (c) the midlatitudes, with interannual and multidecadal variability; and (d) the southwestern subtropics/midlatitudes with a mixture of interannual and decadal variability. These modes are closely connected to anomalous atmospheric circulation patterns, which induce typical forcing mechanisms for each region.
Temperature changes in the western to central Tropics are found to be driven by changes in surface heat fluxes and the horizontal advection of heat, while in the central to eastern Tropics and the northern Benguela region temperature changes are connected to reduced vertical entrainment, altering the depth of the mixed layer and leading to reduced upwelling.
In the western and eastern subtropics, changes in the net surface fluxes drive the upper-ocean temperature anomalies, and wind-induced vertical mixing dissipates them, inducing changes in the depth of the mixed layer. Anomalous heat and volume transports are found to be related to anomalous Ekman and geostrophic currents in the eastern subtropics. A wind-driven mechanism is suggested, whereby changes in Ekman-related heat and volume transport lead to modulations of the subtropical gyre and thus to changes in the geostrophic-related heat and volume transport.
Temporal variability in the midlatitudes is mainly due to horizontal advection and wind-induced vertical mixing, whereby geostrophic advection of heat dominates in the western to central area, and Ekman-induced heat transports are confined to the eastern midlatitudes.
Long-term anterior pituitary function in patients with paediatric Cushing’s disease treated with pituitary radiotherapy
Authors: Chan L F , Storr H L , Plowman P N , Perry L A , Besser G M , Grossman A B , Savage M O 
Published: March 2007

Background/objective: Pituitary radiotherapy (RT) is an effective second-line treatment for paediatric Cushing’s disease (CD). Although the short-term effects of pituitary RT are well documented, there are less data on possible long-term sequelae. We report the long-term anterior pituitary function in a cohort of paediatric CD patients treated with pituitary RT.
Patients and methods: Between 1983 and 2006, 12 paediatric CD patients (10 males and 2 females) of mean age 11.4 years at diagnosis (range 6.4–17.4) underwent second-line pituitary RT (45 Gy in 25 fractions), following unsuccessful transsphenoidal surgery. Out of 12, 11 patients were cured by RT (cure interval 0.13–2.86 years) defined by mean serum cortisol of <150 nmol/l on 5-point day curve and midnight sleeping cortisol of <50 nmol/l. Long-term data are available for six male patients, who received RT at the age of 7.0–17.6 years. The mean follow-up from the completion of RT was 10.5 years (6.6–16.5).
Results: At a mean of 1.0 year (0.11–2.54) following RT, GH deficiency (peak GH <1–17.9 mU/l) was present in five out of six patients. On retesting at a mean of 9.3 years (7.6–11.3) after RT, three out of four patients were GH sufficient (peak GH 19.2–50.4 mU/l). Other anterior pituitary functions including serum prolactin in five out of six patients were normal on follow-up. All the six patients had testicular volumes of 20–25 ml at the age of 14.5–28.5 years.
Conclusion: This series of patients illustrates the absence of serious long-term pituitary deficiency after RT and emphasises the importance of continued surveillance.
Switching to unboosted atazanavir improves glucose tolerance in highly pretreated HIV-1 infected subjects
Authors: Guffanti Monica , Caumo Andrea , Galli Laura , Bigoloni Alba , Galli Andrea , Dagba Geneviéve , Danise Anna , Luzi Livio , Lazzarin Adriano , Castagna Antonella 
Published: March 2007

Objective: To evaluate the 24-week effects on glucose tolerance of switching from a protease inhibitor (PI)-based to an unboosted atazanavir-including regimen in highly pretreated HIV-1 infected subjects with metabolic alterations.
Design: Prospective, open-label, single-center, 24-week pilot study.
Methods: Twenty-one subjects underwent an oral glucose tolerance test (OGTT) at baseline (BL) and after 24 weeks of unboosted atazanavir. Insulin sensitivity and β-cell responsiveness were evaluated on the basis of static and dynamic data; fasting glucose, insulin, C-peptide, triglycerides (TG), total cholesterol (TC), high-density lipoprotein-cholesterol (HDL-c), low-density lipoprotein-cholesterol (LDL-c), TC/HDL-c ratio, CD4+ cell count and HIV-1 RNA were measured.
Results: After 24 weeks of unboosted atazanavir, the 120-min glucose level was significantly lower than the one measured at BL (P=0.021); there were no statistically significant differences in the insulin concentration profile. The SIoral, an OGTT-based index of insulin sensitivity, was significantly higher at week 24 (P=0.017); the indices of first- and second-phase β-cell responsiveness did not significantly change. There was no significant difference between BL and 24-week fasting glucose, insulin or C-peptide levels, and consequently no change in fasting homeostasis model assessment indices of insulin sensitivity and β-cell function. There were significant improvements in TG (P=0.009), TC (P=0.0001), LDL-c (P=0.019) and TC/HDL-c ratio (P=0.001), and a similar trend in HDL-c levels (P=0.069). No significant changes in the immunological and virological parameters were detected.
Conclusions: Our results show that switching from a PI-based to an unboosted atazanavir-including regimen leads to a significant improvement in glucose tolerance in highly pretreated HIV-1 infected subjects with metabolic alterations.