bluuebunny/crossref_metadata_2025 huggingface dataset:
Performance monitoring, error processing, and evaluative control following severe TBI
Authors: LARSON MICHAEL J. , KAUFMAN DAVID A.S. , SCHMALFUSS ILONA M. , PERLSTEIN WILLIAM M.
Published: October 2007

Patients with severe traumatic brain injury (TBI) often demonstrate impairments in performance monitoring—an evaluative control process that can be measured using the error-negativity/error-related negativity (Ne/ERN) and post-error positivity (Pe). The Ne/ERN and Pe are event-related potential (ERP) components generated following errors, with current theories suggesting the Ne/ERN reflects automatic performance monitoring and the Pe reflects error processing and awareness. To elucidate the electrophysiological mechanisms of performance monitoring deficits following severe TBI, behavioral and ERP measurements were obtained, whereas participants with severe TBI and neurologically-healthy comparison participants performed a modified color-naming version of the Stroop task. Behaviorally, both groups demonstrated robust response-time (RT) and error-rate interference. Participants with TBI exhibited generalized RT slowing; no significant between-groups interactions were present for RTs or error rates. ERP results indicate Ne/ERN amplitude was attenuated in participants with TBI, whereas the pattern of Pe amplitude did not clearly differentiate groups. Findings suggest the Ne/ERN as a potential electrophysiological marker of evaluative control/performance monitoring impairment following TBI. Implications for future research and potential clinical application as well as potential limitations in conducting electrophysiological research in neurologically-impaired populations are discussed. (JINS, 2007,13, 961–971.)
Dexamphetamine boosts naming treatment effects in chronic aphasia
Authors: WHITING EMMA , CHENERY HELEN J. , CHALK JONATHAN , COPLAND DAVID A.
Published: October 2007

To date, minimal research has investigated the effect of combining dexamphetamine with standard naming therapy after stroke. The present study used a double-blind, placebo-controlled, multiple baseline, crossover design with two individuals in the chronic stage of stroke recovery. Each individual attended two 4-week blocks of naming therapy (two to three treatment sessions per week). Dexamphetamine (10 mg) was administered at the start of each session during one therapy block, while a placebo was administered during the other therapy block. Therapy progress on treated and untreated items was assessed by a confrontation naming task during and after each therapy block. Both individuals showed greater progress in therapy and maintenance of therapy gains when behavioral treatment was combined with dexamphetamine rather than placebo, although this gain was only statistically significant in one individual. There was no significant improvement on a control task (nonword reading) in either individual. The results provide preliminary evidence that dexamphetamine paired with combined semantic and phonological therapy may be beneficial for the treatment of naming disorders in chronic aphasia. (JINS, 2007,13, 972–979.)
Neuropsychological correlates of alexithymia in Parkinson's disease
Authors: COSTA ALBERTO , PEPPE ANTONELLA , CARLESIMO GIOVANNI AUGUSTO , SALAMONE GIOVANNA , CALTAGIRONE CARLO
Published: October 2007

There are recent reports that alexithymia may be associated with brain dysfunction involving frontal lobes or right hemisphere regions. However, little is known about the relationship between alexithymia and cognitive deficits in Parkinson's disease (PD). The authors investigated the neuropsychological correlates of alexithymia in a population of 70 nondemented PD patients and 70 controls. Alexithymia was screened using the 20-item version of the Toronto Alexithymia Scale (TAS-20). Standardized scales that measure verbal episodic memory, executive functions, abstract reasoning, and visual–spatial and language abilities were adopted. PD patients with alexithymia performed worse than both PD patients without alexithymia and controls with or without alexithymia on tasks requiring visual–spatial processing. Moreover, regression analyses showed that, in PD patients, but not in controls, poor performance on a constructional praxis task predicted high scores on the TAS-20 subscale, which assesses difficulty in identifying emotions. These data evidence an association between alexithymia and visual–spatial processing alterations in PD patients, supporting the view that the right hemisphere could be specifically involved in the modulation of some facets of alexithymia. (JINS, 2007, 13, 980–992.)
Effect of memory impairment on training outcomes in ACTIVE
Authors: UNVERZAGT FREDERICK W. , KASTEN LINDA , JOHNSON KATHY E. , REBOK GEORGE W. , MARSISKE MICHAEL , KOEPKE KATHY MANN , ELIAS JEFFREY W. , MORRIS JOHN N. , WILLIS SHERRY L. , BALL KARLENE , REXROTH DANIEL F. , SMITH DAVID M. , WOLINSKY FREDRIC D. , TENNSTEDT SHARON L.
Published: October 2007

Cognitive training improves mental abilities in older adults, but the trainability of persons with memory impairment is unclear. We conducted a subgroup analysis of subjects in the Advanced Cognitive Training for Independent and Vital Elderly (ACTIVE) trial to examine this issue. ACTIVE enrolled 2802 non-demented, community-dwelling adults aged 65 years and older and randomly assigned them to one of four groups: Memory training, reasoning training, speed-of-processing training, or no-contact control. For this study, participants were defined as memory-impaired if baseline Rey Auditory Verbal Learning Test (AVLT) sum recall score was 1.5 SD or more below predicted AVLT sum recall score from a regression-derived formula using age, education, ethnicity, and vocabulary from all subjects at baseline. Assessments were taken at baseline (BL), post-test, first annual (A1), and second annual (A2) follow-up. One hundred and ninety-three subjects were defined as memory-impaired and 2580 were memory-normal. Training gain as a function memory status (impaired vs. normal) was compared in a mixed effects model. Results indicated that memory-impaired participants failed to benefit from Memory training but did show normal training gains after reasoning and speed training. Memory function appears to mediate response to structured cognitive interventions in older adults. (JINS, 2007, 13, 953–960.)
Complex object-related actions: Structure, meaning, and context
Authors: BUXBAUM LAUREL J.
Published: October 2007

All object-related actions are complex. Even the “simplest” of reach to grasp movements requires finely honed coordination of the muscles of the arm, hand, and fingers; is dependent upon exquisitely tuned feedforward and feedback mechanisms for motor control; is honed by learning; and is influenced by such cognitive factors as task goals. In this sense, then, the title of this Symposium, Complex Object-Related Actions, contains a redundancy. It is also true, however, that (as compared with, say, memory, language, executive function, attention, and spatial skills) the study of skilled action has been neglected within the fields of neuropsychology and cognitive neuroscience. One reason for this finding may be that many psychologists and neuroscientists do not view action as “cognitive” (Rosenbaum, 2005). As the work presented here illustrates, there is ample recent evidence suggesting that this view is inaccurate. We retain the word “Complex” in the title of the Symposium to emphasize the cognitive, psychological, and memory-related aspects of action that deserve broader interest. We suspect that the organizational principles and mechanisms that underlie cognition in many other domains will be found to play a role in the action system as well.
Atmospheric brown clouds: Hemispherical and regional variations in long‐range transport, absorption, and radiative forcing
Authors: Ramanathan V. , Li F. , Ramana M. V. , Praveen P. S. , Kim D. , Corrigan C. E. , Nguyen H. , Stone Elizabeth A. , Schauer James J. , Carmichael G. R. , Adhikary Bhupesh , Yoon S. C.
Published: October 2007

The study uses satellite observations, global assimilated aerosol data sets, Atmospheric Brown Clouds (ABC) observatories, a Monte Carlo aerosol‐cloud‐radiation model and a regional chemical transport model (STEM‐2K) to characterize the spatial extent of brown clouds, regional and megacity ABC hot spots, chemical composition and the direct radiative forcing. It presents the first annual cycle of aerosol observations and forcing from the ABC observatories in the Indo‐Asia‐Pacific regions. East Asia, Indo‐Gangetic Plains, Indonesian region, southern Africa and the Amazon basin are the regional hot spots defined by the criteria that anthropogenic aerosol optical depths (AODs) should exceed 0.3 and absorbing AOD > 0.03. Over these hot spots, as well as in other polluted oceanic regions, the EC mass exceeds 0.5 μg m−3, the OC mass exceeds 2 μg m−3 and sulfate mass exceeds 10 μg m−3 from the surface to 3 km. The brown clouds also have strong seasonal dependence. In the tropics the seasonal dependence is driven by pollution accumulating during the dry seasons, December to February in Northern Hemisphere tropics and June to August in Southern Hemisphere tropics. In the extratropics the pollution peaks during the summer. The brown cloud problem is not restricted to the tropical regions. Over the eastern half of US and western Europe the AODs exceeds 0.2 and absorption AODs exceed 0.02. Brown clouds also extend well into the western Pacific Ocean, the Indian Ocean reaching as far south as 60°S and the eastern Atlantic Ocean. The largest total SO2 emission occurs over China and US, while SO2 emission per unit surface area is maximum over Germany and England. The largest total EC and OC emissions occur over China, but the largest OC emission per unit surface area occur over India. As a result, the maximum negative annual mean TOA direct forcing is over India and Germany. The surface annual‐diurnal mean dimming over the regional hot spots is of the order of −10 W m−2 and −20 W m−2 over megacity hotpots.
Particulate Ba‐barite and acantharians in the Southern Ocean during the European Iron Fertilization Experiment (EIFEX)
Authors: Jacquet S. H. M. , Henjes J. , Dehairs F. , Worobiec A. , Savoye N. , Cardinal D.
Published: October 2007

Particulate biogenic Ba, Sr and Ca and barite crystal contents from suspended matter were compared with acantharian water column distributions and individual Ba/Sr acantharian skeletal ratios during the European Iron Fertilization Experiment (EIFEX) in the Southern Ocean. In the upper 150 m, results indicate that the particulate biogenic Baxs signal is almost free of barite (BaSO4) particles and follows the same evolution as biomass parameters, implying that Ba is incorporated into or adsorbed onto biologically derived (biogenic) particles of which acantharians could account nearly the whole surface Baxs signal. In contrast, in the mesopelagic zone (150–1000 m), particulate biogenic Baxs is mainly composed of micro‐crystalline barite. Calculations indicate that the combined acantharian associated Ba contents in the upper 150 m and between 150–500 m, if entirely transformed into barite, an unlikely condition, and dispersed in the 150–1000 m layer, could explain up to 20% of the mesopelagic Baxs contents. Our results thus indicate that acantharians are probably not the major source of particulate Ba‐barite in the water column. They support the hypothesis that mesopelagic Baxs is mostly built‐up as the result of biogeochemical processes within aggregates and its usefulness as a proxy of mesopelagic C remineralization.
Broadband low cross‐polarization patch antenna
Authors: Guo Yong‐Xin , Khoo Kah‐Wee , Ong Ling Chuen , Luk Kwai‐Man
Published: October 2007

A broadband 180° microstrip balun is employed as a feed network for the L‐probe square patch antenna. The broadband balun delivers impedance matching, equal amplitude power division, and consistent 180° (±10°) phase shifting over a wide band (∼45%). We demonstrate that the use of the 180° broadband balun affords significant H‐plane cross‐polarization suppression across the wide impedance bandwidth designed for L‐probe patch antennas. The antenna using the 180° broadband balun exhibits a measured impedance bandwidth (SWR < 2) of 37.15%, from 1.6 to 2.33 GHz. Across our bandwidth of interest (1.7 to 2.3 GHz), the measured boresight gain ranges from 6.16 to 8.5 dBi, and the measured H‐plane cross‐polarization levels are consistently well suppressed (<−20 dB).
Effect of instream wood on vertical water flux in low‐energy sand bed flume experiments
Authors: Mutz Michael , Kalbus Edda , Meinecke Stefan
Published: October 2007

In streams, interaction of current with bed forms and solid objects can produce vertical water flux across the streambed. Instream wood is a major obstacle to flow and alters the bed topography of natural sand bed streams. In the present experimental study in large circulating flumes simulating sand bed streams with low constant slope, we compared systems with and without natural quantities of wood. The introduction of wood resulted in the production of irregular bed forms. As a result, flow resistance tripled, and vertical water flux across the streambed increased by a factor of 1.8 to 2.5. The mixing depth was spatially variable and seemed unrelated to the local bed form. After the addition of wood, surface water mixed deeper into the sediments, and the total sediment pore water volume involved in mixing increased by factors of 1.2 to 1.5. The practice of increasing instream wood should be a valuable tool for hyporheic rehabilitation of degraded sand bed streams.
Near global observations of the warm rain coalescence process
Authors: Stephens Graeme L. , Haynes John M.
Published: October 2007

The rate of coalescence of cloud water to rain is estimated using new global satellite observations. The differing sensitivity of the passive measurements of reflected sunlight from MODIS and the cloud radar measurements of CloudSat to the sizes of cloud water particles in low, warm clouds is exploited for this purpose. The method integrates CloudSat radar reflectivity profiles with the MODIS cloud optical depth and effective radius matched to the radar footprint. The thresholds applied to the mean cloud layer reflectivities () are chosen to restrict the observations to the incipient stages of warm rain development. MODIS optical property data provide cloud droplet liquid water path information. These different types of information, when combined, provide a means for estimating the rate of coalescence and hint at a time scale of the coalescence process that varies between about 26 minutes to 3.0 hours.
Possibility of recovery of slip deficit rate between the North American plate and the Pacific plate off Sanriku, northeast Japan
Authors: Ozawa Shinzaburo , Suito Hisashi , Nishimura Takuya , Tobita Mikio , Munekane Hiroshi
Published: October 2007

The analysis of global positioning system (GPS) data shows an increase in the westward ground velocity in Iwate, northeast Japan, from around 2003, after a period of roughly constant crustal deformation rate. The spatiotemporal study of time series of displacements reveals that the westward slip deficit rate increased slightly from 2001 to 2003 at the deeper part of the source region of the 1994 Sanriku‐oki earthquake. The increase has been considerable since January 2003, and the area of increased slip deficit rate has expanded, and now covers the source region of the 1994 Sanriku‐oki earthquake. This indicates that the restoration of the slip deficit rate, which was affected by the 1994 earthquake, was not completed in the period from 1994 to 2003.
Observations of Pi2 pulsations by the Wallops HF radar in association with substorm expansion
Authors: Gjerloev J. W. , Greenwald R. A. , Waters C. L. , Takahashi K. , Sibeck D. , Oksavik K. , Barnes R. , Baker J. , Ruohoniemi J. M.
Published: October 2007

We report the first sub‐auroral Pi2 pulsations observations by a SuperDARN type HF radar. The Wallops radar LOS measurements obtained at ionospheric altitudes, ∼56° magnetic latitude, 23 hour magnetic local time, are shown to be highly correlated with ground magnetic field perturbations obtained at Ottawa. The period of the Pi2 pulsations is 118 s and the m‐number is ∼2.3. The availability of both ionospheric LOS measurements and ground based magnetic field perturbations enable us to constrain the properties of the wave. A predominantly shear Alfven mode wave is able to explain both the amplitude and phase relations of our observations. Although the solar wind dynamic pressure is fairly stable the IMF Bz is highly variable thereby preventing an unambiguous identification of a solar wind trigger. Rather, magnetotail observations of a clear dipolarization and an intensification of the auroral westward electrojet producing a modest ground magnetic bay indicate that the wave is associated with the onset of a weak substorm.
NMDI: A normalized multi‐band drought index for monitoring soil and vegetation moisture with satellite remote sensing
Authors: Wang Lingli , Qu John J.
Published: October 2007

A new index, the Normalized Multi‐band Drought Index (NMDI), is proposed for monitoring soil and vegetation moisture from space. NMDI is defined as , where R represents the apparent reflectance observed by a satellite sensor. Similar to the Normalized Difference Water Index, NMDI uses the 860 nm channel as the reference; instead of using a single liquid water absorption channel, however, it uses the difference between two liquid water absorption channels centered at 1640 nm and 2130 nm as the soil and vegetation moisture sensitive band. Analysis revealed that by combining information from multiple near infrared, and short wave infrared channels, NMDI has enhanced the sensitivity to drought severity, and is well suited to estimate both soil and vegetation moisture. Typical soil reflectance spectra and satellite‐acquired reflectances, are used to validate the usefulness of NMDI. Its application to areas with moderate vegetation coverage, however, needs further investigation.
Geomagnetically trapped antiprotons
Authors: Selesnick R. S. , Looper M. D. , Mewaldt R. A. , Labrador A. W.
Published: October 2007

The distribution of geomagnetically trapped antiprotons from decay of cosmic ray albedo antineutrons is described theoretically. The calculation includes ionization energy loss, inelastic nuclear scattering and annihilation, radial diffusion, and solar cycle and geomagnetic secular variations. The trapped antiproton intensity at satellite altitudes is predicted to be significantly higher than the interplanetary cosmic ray antiproton intensity.
Representing aquifer architecture in macrodispersivity models with an analytical solution of the transition probability matrix
Authors: Dai Zhenxue , Wolfsberg Andrew , Lu Zhiming , Ritzi Robert
Published: October 2007

The multi‐dimensional transition probability model represents hydrofacies architecture in modeling aquifer heterogeneity. The structure of the aquifer architecture is mathematically characterized by a canonical representation of the transition probability matrix, solved by an eigenvalue decomposition method. Whereas the eigenvalue decomposition has been numerically solved previously, we show here that it can be analytically solved under the assumptions that cross‐transition probabilities are dictated by facies proportions and that the juxtapositional tendencies of the facies are symmetric. Although limited by the assumptions, analytical solutions provide more immediate insights about the relationships between transition probability and facies proportion and mean length. The analytical solution is first tested by comparison with the numerical solutions and then used to represent hydrofacies architecture within expressions for the spatial covariance of conductivity and the macrodispersivity. The relationship between the longitudinal macrodispersivity and integral scale, the indicator correlation length, and the facies proportion is represented in an equation for estimating the field‐scale dispersivity. An example is used to show how sedimentary structures, conductivity contrasts, and facies mean lengths affect the scales of the macrodispersivity.
Dynamic evolution of energetic outer zone electrons due to wave‐particle interactions during storms
Authors: Li W. , Shprits Y. Y. , Thorne R. M.
Published: October 2007

Relativistic electrons in the outer radiation belt are subjected to pitch angle and energy diffusion by chorus, electromagnetic ion cyclotron (EMIC), and hiss waves. Using quasi‐linear diffusion coefficients for cyclotron resonance with field‐aligned waves, we examine whether the resonant interactions with chorus waves produce a net acceleration or loss of relativistic electrons. We also examine the effect of pitch angle scattering by EMIC and hiss waves during the main and recovery phases of a storm. The numerical simulations show that wave‐particle interactions with whistler mode chorus waves with realistic wave spectral properties result in a net acceleration of relativistic electrons, while EMIC waves, which provide very fast scattering near the edge of the loss cone, may be a dominant loss mechanism during the main phase of a storm. In addition, hiss waves are effective in scattering equatorially mirroring electrons and may be an important mechanism of transporting high pitch angle electrons toward the loss cone.
Parametric decays, stabilization effects, and electrostatic instabilities due to finite‐amplitude Alfvén waves in a fast solar wind‐like plasma
Authors: Gomberoff L.
Published: October 2007

The effects of a finite‐amplitude Alfvén wave in a plasma system with a proton and an alpha‐particle beam, are studied. The system is described by a fourteenth‐order polynomial providing, thereby, many decay channels for the finite‐amplitude Alfvén wave. Apart from the parametric decays, the finite‐amplitude wave affects very drastically the stability properties of the linear system. It is shown that the large‐amplitude waves can either stabilize or destabilize further linear magnetosonic and ion‐cyclotron instabilities like in the case of one ion beam. However, as opposed to the case of one ion beam, for large enough amplitude of the finite‐amplitude wave, the effect on the linear system is always stabilizing. The finite‐amplitude waves can also trigger nonlinear purely electrostatic ion‐acoustic‐like instabilities. However, in the present case, even forward propagating Alfvén waves can destabilize electrostatic waves supported by the beams, something that does not happen when there is only one beam. Thus the saturation mechanism and the existence of nonlinear electrostatic waves in the presence of a finite‐amplitude wave is preserved in a two‐ion‐beam system. We believe that the present study reinforces previous results, involving only one ion‐beam, relative to unresolved issues in the fast solar wind.
On induction effects of geomagnetic daily variations from equatorial electrojet and solar quiet sources at low and middle latitudes
Authors: Kuvshinov Alexei , Manoj Chandrasekharan , Olsen Nils , Sabaka Terence
Published: October 2007

We investigate the spatiotemporal behavior of the magnetic vertical component, Z, of the daily ionospheric current systems: the equatorial electrojet (EEJ) and solar quiet (Sq) variations, considering induction in the mantle and oceans. The inducing EEJ and Sq current systems are provided by the comprehensive model of Sabaka et al. (2004). The three‐dimensional (3‐D) conductivity model of the Earth includes oceans of laterally variable conductance and a spherical conductor (1‐D) underneath. Our model studies demonstrate that induction effects in Z due to the EEJ are negligible everywhere inland for all local times. At CHAMP altitude (400 km) the magnetic signal induced by EEJ above the oceans does not exceed 2–5% of the external field during local noon. This, in particular, means that considering the induction effects is not necessary when modeling the EEJ current strength from inland surface magnetic measurements and/or satellite data. As expected, induction in the oceans strongly affects the Sq field. The model studies show that the anomalous induction effect (defined as the difference between results obtained with 1‐D and 3‐D conductivity models) of Sq is substantial at CHAMP altitude, comprising 50% of the total field. It is therefore necessary to consider induction in the oceans when modeling Sq variations for both ground‐based and satellite data. Finally, we demonstrate that the anomalous behavior of the daily variations in Z at south Indian sites, namely, a large positive prenoon peak, can be explained by 3‐D induction of the Sq variations, with no contribution from the EEJ.
Mass accommodation coefficient of water: A combined computational fluid dynamics and experimental data analysis
Authors: Voigtländer J. , Stratmann F. , Niedermeier D. , Wex H. , Kiselev A.
Published: October 2007

The mass accommodation coefficient αmass of water vapor in NaCl solutions has been studied for realistic lower atmospheric conditions. To determine αmass, a combination of experimental data and computational fluid dynamics (CFD) modeling has been applied. Experiments were performed at the Leipzig Aerosol Cloud Interaction Simulator (LACIS), a laminar flow diffusion tube for measurements of both hygroscopic growth and cloud condensation nuclei (CCN) activation. Quasi‐monodisperse sodium chloride particles with 54 nm and 108 nm in diameter have been used as condensation nuclei. To characterize particle growth, mean droplet diameters have been measured at the outlet of LACIS with a white‐light optical particle spectrometer. Measurements were performed for different saturation ratios in the range between 1.0 and 1.02. Experiments have been modeled using the Computational Fluid Dynamics Code (CFD‐Code) FLUENT6 combined with the Fine Particle Model (FPM). For determination of αmass, measured droplet diameters have been compared with calculated ones. The accommodation coefficient in the theoretical calculations was varied to achieve a quantitative comparison with the measurements. Experimental data shown in this study are consistent with αmass > 0.30. Therefore our results support previous studies applying different experimental techniques.
Improving lightning location goodness of fit by compensating propagation effects of stratified ground
Authors: Schueler J. R. , Thomson E. M.
Published: October 2007

Higher frequencies were attenuated from lightning ground waves received at the five stations of a time‐of‐arrival (TOA) lightning location network at Kennedy Space Center (KSC) on 10 September 1992. Lightning location goodness of fit was worsened because propagation effects that varied among propagation paths caused the tagged points in time on the pulses to be nonuniformly delayed. To recover some of the lost information, a stratified ground model and the method of least squares were used to estimate ground conductivity, associated time tag delay, stratum thickness, source height, and station gain. The source pulse estimates for one fortuitous lightning were similar enough among stations to suggest that the lightning originated at a point. The point was just inside of the five‐station array within the line of sight (LOS) of each station, the propagation path to Station 2 was over seawater, and the lightning location goodness of fit was significantly improved.
Erythropoietin protects the human myocardium against hypoxia/reoxygenation injury via phosphatidylinositol‐3 kinase and ERK1/2 activation
Authors: Mudalagiri N R , Mocanu M M , Di Salvo C , Kolvekar S , Hayward M , Yap J , Keogh B , Yellon D M
Published: October 2007

Background and purposes:

Erythropoietin (EPO) has been shown to protect against myocardial infarction in animal studies by activating phosphatidylinositol‐3 kinase (PI3K)/Akt and ERK1/2. However these pro‐survival pathways are impaired in the diabetic heart. We investigated the ability of EPO to protect human atrial trabeculae from non‐diabetic and diabetic patients undergoing coronary artery bypass surgery, against hypoxia‐reoxygenation injury.

Experimental approach:

Human atrial trabeculae were exposed to 90min hypoxia and 120min reoxygenation. EPO was administered throughout reoxygenation. The developed force of contraction, calculated as a percentage of baseline force of contraction, was continuously monitored. The involvement of PI3K and ERK1/2 and the levels of activated caspase 3(AC3) were assessed.

Key results:

EPO improved the force of contraction in tissue from non‐diabetic patients (46.7+/‐1.7% vs. 30.2+/‐2.2% in control, p<0.001). These beneficial effects were prevented by the PI3K inhibitor, LY294002 and the ERK1/2 inhibitor, U0126. EPO also significantly improved the force of contraction in the diabetic tissue, although to a lesser degree. The levels of activated caspase 3 were significantly reduced in EPO treated trabeculae from both non‐diabetic and diabetic patients, relative to their respective untreated controls.

Conclusions and implications:

EPO administered at reoxygenation protected human myocardial muscle by activating PI3K and ERK1/2 and reducing the level of activated caspase 3. This cardioprotection was also observed in the diabetic group. This data supports the potential of EPO being used as a novel cardioprotective strategy either alone or as an adjunct in the clinical setting alongside existing reperfusion therapies.

British Journal of Pharmacology (2008) 153, 50–56; doi:10.1038/sj.bjp.0707461; published online 22 October 2007
Reperfusion and calculated RISKs: pharmacological postconditioning of human myocardium
Authors: Baxter G F , Burley D S
Published: October 2007

The last five years have witnessed a remarkable resurgence of interest in myocardial reperfusion injury. Reperfusion is absolutely essential to salvage ischaemic myocardium but experimental and clinical studies show that reperfusion‐associated injury may mask the full benefits of prompt reperfusion in acute myocardial infarction. In the current issue of the British Journal of Pharmacology, Mudalagiri et al demonstrate a protective effect against simulated reperfusion injury using exogenously applied erythropoietin in human isolated myocardium. Crucially, the benefits of erythropoietin were observed when it was administered specifically during re‐oxygenation. The demonstration that the protective effects of the cytokine were dependent on PI3‐kinase/Akt and ERK1/2 activation provides compelling evidence that reperfusion injury salvage kinases (RISKs) are key survival mechanisms in human myocardium, as they are in experimental animal species. Although erythropoietin may be only one of several potential pharmacological approaches in human patients, this study establishes the important proof‐of‐principle that activation of RISKs is protective in human myocardium and could be a promising therapeutic target in acute myocardial infarction.

British Journal of Pharmacology (2008) 153, 1–3; doi:10.1038/sj.bjp.0707498; published online 22 October 2007
CB2 receptors as new therapeutic targets for liver diseases
Authors: Lotersztajn S , Teixeira‐Clerc F , Julien B , Deveaux V , Ichigotani Y , Manin S , Tran‐Van‐Nhieu J , Karsak M , Zimmer A , Mallat A
Published: October 2007

Cannabinoid type‐1 (CB1) and type‐2 (CB2) receptors belong to the family of G protein‐coupled receptors and mediate biological effects of phyto‐derived and endogenous cannabinoids. Whereas functions of CB1 receptor have been extensively studied, the CB2 receptor has emerged over the last few years as a critical player in regulation of inflammation, pain, atherosclerosis and osteoporosis. Therefore, although still at a preclinical stage, the development of selective CB2 molecules has gained of interest as new targets in drug discovery. Recent data have unravelled a key role of CB2 receptors during chronic and acute liver injury, including fibrogenesis associated to chronic liver diseases, ischaemia‐reperfusion‐induced liver injury, and hepatic encephalopathy associated to acute liver failure. This review summarizes the latest advances on the recently identified role of CB2 receptors in the pathophysiology of liver diseases.

British Journal of Pharmacology(2008)153, 286–289; doi:10.1038/sj.bjp.0707511; published online 22 October 2007
Inflammatory response and cardioprotection during open‐heart surgery: the importance of anaesthetics
Authors: Suleiman M‐S , Zacharowski K , Angelini G D
Published: October 2007

Open‐heart surgery triggers an inflammatory response that is largely the result of surgical trauma, cardiopulmonary bypass, and organ reperfusion injury (e.g. heart). The heart sustains injury triggered by ischaemia and reperfusion and also as a result of the effects of systemic inflammatory mediators. In addition, the heart itself is a source of inflammatory mediators and reactive oxygen species that are likely to contribute to the impairment of cardiac pump function. Formulating strategies to protect the heart during open heart surgery by attenuating reperfusion injury and systemic inflammatory response is essential to reduce morbidity. Although many anaesthetic drugs have cardioprotective actions, the diversity of the proposed mechanisms for protection (e.g. attenuating Ca2+ overload, anti‐inflammatory and antioxidant effects, pre‐ and post‐conditioning‐like protection) may have contributed to the slow adoption of anaesthetics as cardioprotective agents during open heart surgery. Clinical trials have suggested at least some cardioprotective effects of volatile anaesthetics. Whether these benefits are relevant in terms of morbidity and mortality is unclear and needs further investigation. This review describes the main mediators of myocardial injury during open heart surgery, explores available evidence of anaesthetics induced cardioprotection and addresses the efforts made to translate bench work into clinical practice.

British Journal of Pharmacology (2008) 153, 21–33; doi:10.1038/sj.bjp.0707526; published online 22 October 2007
Reaction coordinates and transition pathways of rare events via forward flux sampling
Authors: Borrero Ernesto E. , Escobedo Fernando A.
Published: October 2007

A new approach is developed for identifying suitable reaction coordinates to describe the progression of rare events in complex systems. The method is based on the forward flux sampling (FFS) technique and standard least-square estimation (LSE) and it is denoted as FFS-LSE. The FFS algorithm generates trajectories for the transition between stable states as chains of partially connected paths, which can then be used to obtain “on-the-fly” estimates for the committor probability to the final region, pB. These pB data are then used to screen a set of candidate collective properties for an optimal order parameter (i.e., reaction coordinate) that depends on a few relevant variables. LSE is used to find the coefficients of the proposed reaction coordinate model and an analysis of variance is used to determine the significant terms in the model. The method is demonstrated for several test systems, including the folding of a lattice protein. It is shown that a simple approximation to pB via a model linear on energy and number of native contacts is sufficient to describe the intrinsic dynamics of the protein system and to ensure an efficient sampling of pathways. In addition, since the pB surface found from the FFS-LSE approach leads to the identification of the transition state ensemble, mechanistic details of the dynamics of the system can be readily obtained during a single FFS-type simulation without the need to perform additional committor simulations.
Mesoscopic simulations of accelerated polymer drift in microfluidic capillaries
Authors: Berkenbos A. , Lowe C. P.
Published: October 2007

We use a mesoscopic simulation technique to study the transport of polymers in dilute solution flowing through a cylindrical tube. The simulations use an explicit solvent model to include all the relevant hydrodynamic couplings and a coarse grained ideal chain model for the polymers (appropriate for systems near the theta temperature). For the interactions between the solvent and the tube wall we use a novel method that ensures continuity of the stress at the interface. We show that the results for the polymer drift velocity are independent of the degree of coarse graining. Further, for the case where the size of the chains is small but not negligible compared to the tube radius, our results are in excellent agreement with experiment. However, they also show that in this regime, the “accelerated” drift, relative to the average solvent flow velocity, is described by the steric effect of the tube wall excluding the polymer center of mass from sampling the full cross section of the tube. Hydrodynamic interactions have a negligible influence in this regime. Consequently, the agreement between experiment and theories that approximates the former but includes the latter is fortunate. When the undisturbed polymer radius approaches or exceeds the tube radius, the hydrodynamic interactions do have a significant effect. They reduce the drift velocity, in qualitative agreement with theoretical predictions. The accelerated drift still approaches the maximum value, one would expect based on a Poiseuille flow but more slowly than if one neglects hydrodynamics. Finally, we propose an empirical fit that accurately describes data in the intermediate regime.
Frozen core and effective core potentials in symmetry-adapted perturbation theory
Authors: Patkowski Konrad , Szalewicz Krzysztof
Published: October 2007

The application of the frozen-core approximation (FCA) and effective core potentials (ECPs) within symmetry-adapted perturbation theory (SAPT) has been investigated and implemented. Unlike in the case of conventional electronic-structure theories, the development of a frozen-core version of SAPT is not straightforward. In particular, the FCA realizations neglecting excitations from core orbitals and restricting all summation indices to valence orbitals only are no longer equivalent. It is shown that it is necessary in SAPT to keep some terms containing products of the valence orbitals of one monomer and the core orbitals of the other one in the exchange-energy components. When these terms are included or, equivalently, the “infinite-excitation-energy” approximation omitting only the excitations from the core orbitals is used, the accuracy of the frozen-core approximation in SAPT matches that obtained in supermolecular perturbational and coupled-cluster methods. If these terms are neglected, i.e., within the “index-range-restriction” approximation, several exchange corrections are significantly underestimated. When ECPs are used in SAPT, the accuracy of the interaction energies is as good as in conventional supermolecular methods, provided that the residual supermolecular Hartree-Fock term is included. We have found that only some types of ECPs can be reliably used for calculations of interaction energies both in SAPT and in supermolecular approaches. For systems containing heavy atoms, both FCA and the use of ECPs lead to very significant savings of computer time.
Radical hydrogen bonding: Origin of stability of radical-molecule complexes
Authors: Hernández-Soto Heriberto , Weinhold Frank , Francisco Joseph S.
Published: October 2007

Natural bond orbital analysis is used to investigate the nature of hydrogen bonding in a series of binary open-shell complexes involving hydroperoxy radical HO2⋯X and analogous closed-shell H2O2⋯X complexes (where X=H2O, H2O2, HONO, HONO2, CH3OH, HCOOH, CH3COOH, and H2SO4) in order to elucidate and identify the electronic factors responsible for the strength of radical hydrogen bonds. Results from this study suggest that the radical species strongly alters the strength of the characteristic n→σ* donor-acceptor interaction in the hydrogen bonding. This interaction is found to contribute to the unusually strong binding in radical-molecule complexes. These findings have important new ramifications for our fundamental understanding of radical hydrogen bonds.
Behavior of a polymer chain immersed in a binary mixture of solvents
Authors: Sumi Tomonari , Kobayashi Kazuhiko , Sekino Hideo
Published: October 2007

The behavior of a polymer chain immersed in a binary solvent mixture is investigated via a single-polymer simulation using an effective Hamiltonian, where the solvent effects are taken into account through a density-functional theory for polymer-solvent admixtures. The liquid-liquid phase separation of the binary solvent mixture is modeled as that of a Lennard-Jones binary fluid mixture with weakly attractive interactions between the different components. Two types of energetic preferences of the polymer chain for the better solvent—(A) no preferential solvophilicity and (B) strong preferential solvophilicity—are employed as polymer-solvent interaction models. The radius of gyration and the polymer-solvent radial distribution functions are determined from the simulations of various molar fractions along an isotherm slightly above the critical temperature of the liquid-liquid phase separation. These quantities near the critical point conspicuously depend on the strength of the preferential solvophilicity. In the case where the polymer exhibits a strong preferential solvophilicity, a remarkable expansion of the polymer chain is observed near the critical point. On the other hand, in the case where the polymer has no preferential solvophilicity, no characteristic variation of the polymer conformation is observed even near the critical point. These results indicate that the expansion of a polymer chain enhances the local phase separation around it, acting as a nucleus of demixing in the vicinity of the critical point. This phenomenon in binary solvents near the liquid-liquid critical point is similar to the expansion of the polymer chain in one-component supercritical solvents near the liquid-vapor critical point, which we have reported [T. Sumi and H. Sekino J. Chem. Phys. 122, 194910 (2005)].
Ge film growth in the presence of Sb by metal organic chemical vapor deposition
Authors: Kim Ran-Young , Kim Ho-Gi , Yoon Soon-Gil
Published: October 2007

The germanium films were deposited on TiAlN bottom electrode at various temperatures by metal organic chemical vapor deposition using Ge(allyl)4(Ge(C3H5)4) and Sb(iPr)3(Sb(C3H7)3) precursors. Deposition of germanium films was only possible by a catalytic role of Sb metal by a thermal decomposition of Sb(iPr)3(Sb(C3H7)3) precursors. Deposition rate of the Ge films increases with increasing Sb bubbling temperature at a substrate temperature of 370°C. The deposition characteristics of Ge films were controlled by a surface reaction in the temperature range from 360to380°C and were controlled by a mass transport in the range of 380–400°C. The step coverage of Ge films in 500×200nm2 trench structure was approximately 93% at a substrate temperature of 370°C.
Chaos suppression through asymmetric coupling
Authors: Bragard J. , Vidal G. , Mancini H. , Mendoza C. , Boccaletti S.
Published: October 2007

We study pairs of identical coupled chaotic oscillators. In particular, we have used Roessler (in the funnel and no funnel regimes), Lorenz, and four-dimensional chaotic Lotka-Volterra models. In all four of these cases, a pair of identical oscillators is asymmetrically coupled. The main result of the numerical simulations is that in all cases, specific values of coupling strength and asymmetry exist that render the two oscillators periodic and synchronized. The values of the coupling strength for which this phenomenon occurs is well below the previously known value for complete synchronization. We have found that this behavior exists for all the chaotic oscillators that we have used in the analysis. We postulate that this behavior is presumably generic to all chaotic oscillators. In order to complete the study, we have tested the robustness of this phenomenon of chaos suppression versus the addition of some Gaussian noise. We found that chaos suppression is robust for the addition of finite noise level. Finally, we propose some extension to this research.
Molecular dynamics simulation of polymer electrolytes based on poly(ethylene oxide) and ionic liquids. II. Dynamical properties
Authors: Costa Luciano T. , Ribeiro Mauro C. C.
Published: October 2007

Dynamical properties of polymer electrolytes based on poly(ethylene oxide) (PEO) and ionic liquids of 1-alkyl-3-methylimidazolium cations were calculated by molecular dynamics simulations with previously proposed models [L. T. Costa and M. C. Ribeiro, J. Chem. Phys. 124, 184902 (2006)]. The effect of changing the ionic liquid concentration, temperature, and the 1-alkyl-chain lengths, [1,3-dimethylimidazolium]PF6 and [1-butyl-3-methylimidazolium]PF6 ([dmim]PF6 and [bmim]PF6), was investigated. Cation diffusion coefficient is higher than those of anion and oxygen atoms of PEO chains. Ionic mobility in PEO∕[bmim]PF6 is higher than in PEO∕[dmim]PF6, so that the ionic conductivity κ of the former is approximately ten times larger than the latter. The ratio between κ and its estimate from the Nernst-Einstein equation κ∕κNE, which is inversely proportional to the strength of ion pairs, is higher in ionic liquid polymer electrolytes than in polymer electrolytes based on inorganic salts with Li+ cations. Calculated time correlation functions corroborate previous evidence from the analysis of equilibrium structure that the ion pairs in ionic liquid polymer electrolytes are relatively weak. Structural relaxation at distinct spatial scales is revealed by the calculation of the intermediate scattering function at different wavevectors. These data are reproduced with stretched exponential functions, so that temperature and wavevector dependences of best fit parameters can be compared with corresponding results for polymer electrolytes containing simpler ions.
Excitation, dynamics, and control of rotationally autoionizing Rydberg states of H2
Authors: Kirrander A. , Fielding H. H. , Jungen Ch.
Published: October 2007

The dynamics of rotationally autoionizing Rydberg states of molecular hydrogen is investigated using a time-dependent extension of multichannel quantum defect theory, in which the time-dependent wave packets are constructed using first-order perturbation theory. An analytical expression for the complex excitation function for a sequence of Gaussian excitation pulses is derived and then employed to investigate the influence of pairs of pulses with well-defined phase differences on the decay dynamics and final-state composition.
Magnetoresistance response of cobalt nanocontacts between extended magnetic electrodes
Authors: Sarau G. , Schneider C. M.
Published: October 2007

The magnetoresistance response of cobalt nanocontacts with varying geometries formed between two extended electrodes has been experimentally investigated and linked to micromagnetic simulations. The contribution of the nanoconstriction to the measured magnetoresistance signal has been separated from that of the electrode bulk. The different nanocontact geometries exhibit different shape anisotropies resulting in a characteristic behavior of the magnetization at each nanocontact. The magnetization reversal processes are explained on the basis of the anisotropic magnetoresistance and domain wall scattering effects. The domain wall resistance takes positive values, which is in agreement with models based on the spin mistracking inside the domain wall.
Measurement of human heartbeat and respiration signals using phase detection radar
Authors: Kim Hyoung Jong , Kim Ki Ho , Hong Yun Seok , Choi Jin Joo
Published: October 2007

This article introduces a low-cost phase detection radar aimed at measuring the human heartbeat and respiration signals without any physical connections to the human body. A continuous-wave radar targeting the chest will detect the phase difference, resulted by the time-varying target position of the heartbeat, between the transmitted signal and the reflected signal. We have tested the developed radar to measure the heartbeat and respiration signals at a distance of about 40cm from the chest.