bluuebunny/crossref_metadata_2025 huggingface dataset:
Biochemical composition and metabolic pathways of filarial worms Setaria cervi: search for new antifilarial agents
Authors: Ahmad Rumana , Srivastava Arvind K.
Published: September 2007

The main problem regarding the chemotherapy of filariasis is that no safe and effective drug is available yet to combat the adult human filarial worms. Setaria cervi, the causal organism of setariasis and lumbar paralysis in cattle, is routinely employed as a model organism for conducting biochemical and enzymatic studies on filarial parasites. In view of the practical difficulties in procuring human strains of Wuchereria bancrofti and Brugia malayi for drug screening, the bovine filarial parasite S. cervi, resembling the human species in having microfilarial periodicity and chemotherapeutic response to known antifilarial agents, is widely used as a model in such studies. For a rational approach to antifilarial chemotherapy, knowledge of the biochemical composition and metabolic pathways of this helminth parasite may be of paramount importance, so that more potent antifilarial agents based on specific drug targets can be identified in drug discovery programmes. The present review provides an update on the biochemistry of the important metabolic pathways functioning within this potentially important bovine parasite, that have so far been studied, and on those that need to be investigated further so as to identify novel drug targets that can be exploited for designing new antifilarial drugs.
Patterns of parasitic infections in faecal samples from stray cat populations in Qatar
Authors: Abu-Madi M.A. , Al-Ahbabi D.A. , Al-Mashhadani M.M. , Al-Ibrahim R. , Pal P. , Lewis J.W.
Published: September 2007

The parasite fauna of stray cat populations, comprising mainly helminth parasites, is described for the first time from the arid environment of the Qatar peninsula. During the winter and summer months of 2005, 824 faecal samples were examined from six sites in Qatar. Up to seven species of parasites were identified, six of which were nematodes –Strongyloides stercoralisas the most prevalent (18.4%), followed byAelurostrongylus abstrusus(7.5%),Toxocara cati(6.1%),Ancylostoma tubaeforme(5.9%) andPhysalopterasp. (4.8%) andToxascaris leonina(0.7%) – and one sporozoan species,Isospora felis(0.5%). Unidentified cestode eggs were also recovered from 10.7% of samples examined. The parasite species were found to be highly overdispersed in faecal samples from all sites, whereas the prevalence and intensity of infections were influenced by site and season. Infection levels tended to be higher during the winter season, especially in the case ofA. abstrususandA. tubaeforme, when conditions of temperature and humidity were more favourable for the development of egg and/or larval stages of parasites compared with the extremely hot and dry summer months. The results are discussed in relation to the distribution of the cat population in the vicinity of Doha and its outskirts and the potential threat of parasite transmission to human communities in Qatar.
Lack of preference for infective faeces inHymenolepis diminuta-infected beetles (Tenebrio molitor)
Authors: Shea John F.
Published: September 2007

The beetle–tapeworm life cycle provides a convenient system to study how host behaviour influences the probability of re-infection because initial and secondary infections can be tracked. The beetle,Tenebrio molitor, is infected with the tapewormHymenolepis diminutawhen it ingests rat faeces containing tapeworm eggs, which upon hatching undergo five morphologically distinct stages while developing inside the beetle. In a series of preference trials, both individual and groups of previously infected beetles were exposed to baits of infective (faeces with eggs) and uninfective faeces. Beetles did not differ in the amount of time spent or in the number of occurrences at each bait type, suggesting that infected beetles show no preference for infective faeces. This may be a host adaptation to avoid further infection, parasite manipulation to avoid competition for host resources, or both. Further, once infected, beetles are no more or no less likely to become re-infected than uninfected beetles. An analysis of the mean and variance of infection suggests that some individuals are highly susceptible to and some are highly resistant to infection, with males being more variable than females. This could explain the higher load of cysticercoids observed in males.
Parasite development and visceral pathology inGalba truncatulaco-infected withFasciola hepaticaandParamphistomum daubneyi
Authors: Rondelaud D. , Vignoles P. , Dreyfuss G.
Published: September 2007

Histological investigations inGalba truncatulanaturally or experimentally co-infected withFasciola hepaticaandParamphistomum daubneyiwere carried out to study parasite development and the responses of the digestive gland and kidney of snails, as larval forms of these digeneans often use these two sites for their growth within the snail's body. The number of live rediae per snail ranged from 2.4 to 4.2 for the dominating parasite (it developed in the digestive gland) and was less than 2.0 for the other species. When the dominating species wasF. hepatica, most snails harboured cercariae-containing rediae; if this parasite wasP. daubneyi, procercariae-containing rediae with or without free procercariae were observed in most snails. In contrast, most rediae of the other species were immature. The pathology caused by the dominating species in the digestive gland was greater than that recorded in the kidney, where the other parasite was generally located. The most frequent tissue lesions in the digestive gland were generalized epithelial necrosis and epithelial reconstitution. In the kidney, multifocal epithelial necrosis was frequently observed, particularly whenP. daubneyiwas the dominating species. The frequencies of lesions in the digestive gland agreed with percentages reported by our team in other snails mono-infected withF. hepaticaorP. daubneyi. In contrast, multifocal necrosis in the kidney was clearly greater in the present study and this finding might be explained by assuming that a sufficient number of free larvae within the snail would be necessary for the development of epithelial necrosis in the whole kidney.
Timing of removal of pacing wires following paediatric cardiac surgery
Authors: Jowett Victoria , Hayes Nicholas , Sridharan Shankar , Rees Philip , Macrae Duncan
Published: September 2007

Background

Temporary percutaneous epicardial pacing wires are routinely placed in children following cardiac surgery. There is uncertainty in clinical practice about the optimum timing for their removal, and practice varies widely both within and between different institutions.

Aim

The aim of our study was to describe the use of temporary pacing in children undergoing cardiac surgery.

Methods

We performed a prospective audit of 140 children following cardiac surgery in two institutions. Information on diagnosis, surgical procedure, occurrence of arrhythmias, use of pacing wires, timing of removal of the wire, and complications related to removal was recorded on a daily basis from clinical records.

Results

We studied 140 patients undergoing a total of 141 operations. Of these, 39 (28%) required pacing postoperatively. In 38, pacing was required within the first 24 hours. One patient, who was in nodal rhythm for the first 24 hours, required pacing on the second postoperative day, while 29 patients required pacing beyond the first 24 hours. No patient in sinus rhythm on the first postoperative day required new pacing after this time. The median time to removal of the pacing wires was 4.5 days, with an inter-quartile range from 2 to 9 days. Complications included malfunction of atrial wires in 2 patients.

Conclusions

Our study shows that no patient who was in sinus rhythm for the first 24 hours post-operatively required pacing before their discharge from hospital. This suggests that, in those patients in a stable state of sinus rhythm, and who have not required pacing within the first 24 hours, it may be safe to remove pacing wires after 24 hours. This could be timed to coincide with the removal of chest drains, thus avoiding the need for multiple distressing procedures.
Assessing models for ionospheric weather specifications over Australia during the 2004 Climate and Weather of the Sun‐Earth‐System (CAWSES) campaign
Authors: Sojka J. J. , Thompson D. C. , Scherliess L. , Schunk R. W. , Harris T. J.
Published: September 2007

The Utah State University (USU) Global Assimilation of Ionospheric Measurements (GAIM) program is developing assimilation models to specify ionospheric weather. In this study the Gauss Markov Kalman Filter (GMKF) GAIM model was used. The period 20 March through 19 April 2004, which spanned the Climate and Weather of the Sun‐Earth‐System (CAWSES) first study period, has been extensively studied to validate the performance of the GAIM model. Although the USU‐GAIM model has both regional and global capabilities and can assimilate data from a wide variety of ionospheric observations, for this study the GMKF model was run in a global mode using data only from 162 ground‐based GPS slant total electron content (TEC) stations and in situ measurements from three satellites. Using measurements from the 11 ionosonde stations of the Australian Department of Defence sounder network as an independent bottomside ground‐truth, the International Reference Ionosphere (IRI), Ionospheric Forecast Model (IFM), and GMKF were compared for (1) monthly mean climatology and (2) the day‐to‐day weather during the 31 day period. A skill score was developed for the day‐to‐day weather by defining the IRI as the reference model. IFM is found to be a 10% improvement, while the GMKF is 39% more capable to capture weather variability. However, the study also identifies that this global version of GMKF has difficulty around sunrise, during which time the GMKF performance can be poorer than IRI. Excluding this interval from the skill score analysis increases the GMKF ability to track weather to 48%. The use of more data and different data types should further increase the GMKF's ability to capture weather variations.
Two‐dimensional stokes flow around a heated cylinder: A possible application for diapirs in the mantle
Authors: Ziethe R. , Spohn T.
Published: September 2007

It is widely assumed that the separation of metal and silicates in a homogeneously accreted protoplanet occurred rather rapidly. The process of core formation through the descent of large, hot, iron‐rich bodies through a cold, silicate protoplanet is discussed. If iron diapirs sink toward the planet center with the Stokes velocity, they would require more than 800 Ma to form a core in the case of a planet similar to the Earth. We therefore implement a temperature‐dependent rheology for the silicate material surrounding the diapir, which leads to a reduction of the drag force exerted on the iron drop. We compare the drag force for different sinking velocities to the body force on the diapir and find that the terminal velocity in the temperature‐dependent viscosity model is a factor of 30 higher than that in an isoviscous medium. On the basis of these results, the core formation time for the Earth could be as little as 30 Ma.
Heterogeneous oxidation of sulfur dioxide by ozone on the surface of sodium chloride and its mixtures with other components
Authors: Li L. , Chen Z. M. , Zhang Y. H. , Zhu T. , Li S. , Li H. J. , Zhu L. H. , Xu B. Y.
Published: September 2007

The heterogeneous oxidation of SO2 by O3 on NaCl particles has been studied using diffuse reflectance infrared Fourier transform spectroscopy. The formation of sulfite and sulfate on the surface was identified, and the roles of O3 and water in the oxidation processes were determined. The results showed that in the presence of O3, SO2 could be oxidized to sulfate on the surface of NaCl particles. The reaction is first order in O3 and zero order in SO2. The initial reactive uptake coefficient for SO2 [(0.6–9.8) × 1014 molecule cm−3] oxidation by O3 [(1.2–12) × 1014 molecule cm−3] was determined to be (4.8–0.7) × 10−8 using the Brunauer‐Emmett‐Teller area as the reactive area and (9.8–1.4) × 10−5 using the geometric area at 40% relative humidity. A three‐stage mechanism that involves the adsorption of O3 results in an alkalescent surface, the adsorption of SO2 followed by O3 oxidation is proposed, and the adsorption of O3 on the NaCl surface is the rate‐determining step. The proposed mechanism can well explain the experiment results. Furthermore, the surface oxidation on mixtures of NaCl with other components such as CaCO3, Al2O3, TiO2, MgCl2 6H2O, MgO, elemental carbon, and soot were studied. The reactivity of mixtures can be predicted from the reactivity of the single component with each component weighted by its abundance in the mixture. The catalytic and basic additives could enhance the production of sulfate on the NaCl surface.
Wavelet‐like efficient analysis of two‐dimensional arbitrarily shaped radomes using a surface formulation
Authors: Quesada‐Pereira F. D. , Vidal A. , Boria V. E. , Alvarez‐Melcón A. , Gimeno B.
Published: September 2007

Radomes are usually made of lossy dielectric materials, and their accurate analysis is often cumbersome because of their typical large electrical size and geometrical complexity. In real reflector antenna structures, there are always complex interactions between the radome, the reflector surfaces and the directional feeds, which are typically neglected for the sake of simplicity. In this paper we will consider all such interactions in a very accurate way, thus requiring a high number of unknowns for the numerical solution of the problem. To overcome such drawback, an integral equation formulation based on the Equivalence Principle in combination with the wavelet transform has been employed, obtaining finally a robust and accurate CAD tool for the rigorous analysis of arbitrarily shaped radomes containing continuous and discrete electromagnetic sources. It will be shown that the use of wavelet‐like bases substantially improves the numerical efficiency and memory requirements of the original integral equation method. For verification purposes, the results obtained with the new technique are successfully compared with examples taken from the literature. Complex antenna structures are then discussed in order to prove the usefulness of the new method.
Aging of marine organic matter during cross‐shelf lateral transport in the Benguela upwelling system revealed by compound‐specific radiocarbon dating
Authors: Mollenhauer Gesine , Inthorn Maik , Vogt Thomas , Zabel Matthias , Sinninghe Damsté Jaap S. , Eglinton Timothy I.
Published: September 2007

Organic matter accumulation and burial on the Namibian shelf and upper slope are spatially heterogeneous and strongly controlled by lateral transport in subsurface nepheloid layers. Much of the material deposited in depo‐centers on the slope ultimately derives from the shelf. Supply of organic matter from the shelf involves selective transport of organic matter. We studied these selective transport processes by analyzing the radiocarbon content of co‐occurring sediment fractions. Here we present radiocarbon data for total organic carbon as well as three tracers of surface ocean productivity (phytoplankton‐derived alkenones, membrane lipids of pelagic crenarchaeota (crenarchaeol), and calcareous microfossils of planktic foraminifera) in core‐top and near‐surface sediment samples. The samples were collected on the Namibian margin along a shelf‐slope transect (85 to 1040 m) at 24°S and from the upper slope depo‐center at 25.5°S. In core‐top sediments, alkenone ages gradually increased from modern to 3490 radiocarbon years with distance from shore and with water depth. Crenarchaeol, while younger than alkenones, also increased in age with distance offshore. It was concluded that the observed ages were a consequence of cross‐shelf transport and associated aging of organic matter. Radiocarbon ages of preserved lipid biomarkers in sediments thus at least partially depend on the relative amount of laterally supplied, pre‐aged material present in a sample, highlighting the importance of nepheloid transport for the sedimentation of organic matter over the Namibian margin.
A general method for validating statistical downscaling methods under future climate change
Authors: Vrac M. , Stein M. L. , Hayhoe K. , Liang X.‐Z.
Published: September 2007

Statistical downscaling methods (SDMs) are often used to increase the resolution of future climate projections from coupled atmosphere‐ocean general circulation models (GCMs). However, SDMs are not able to capture small‐scale dynamical changes unresolved by GCMs. For this reason, we propose a two‐step generalized validation process to evaluate the performance of any statistical downscaling method relative to regional climate model (RCM) simulations driven by the same GCM fields. First, we compare historical station‐based observations with simulations obtained from a statistical model fitted to and driven by reanalysis fields, and then driven by historical GCM fields. Then, the SDM is required to produce future projections consistent with RCM simulations used as pseudo‐observations under future emissions scenarios. Using the climate extension of the fifth generation Penn‐State/NCAR Mesoscale Model (CMM5) driven by NCAR/DOE Parallel Climate Model (PCM) simulations, we apply this method to identify the strengths/weaknesses of a nonhomogeneous stochastic weather typing method.
Relationship between the Q factor and inherent optical properties: Relevance to ocean‐colour inversion algorithms
Authors: Devred E. , Sathyendranath S. , Platt T.
Published: September 2007

Conversion between upwelling irradiance and radiance at the sea surface, essential for some aspects of remote sensing of ocean colour, requires knowledge of the Q factor. The Q factor depends on solar zenith angle, satellite viewing angle and the optical properties of the water. For simulated data for two fixed solar zenith angles, we express the Q factor as a function of total absorption and backscattering coefficients. The new parameterisation is used in an algorithm to retrieve total water backscattering from in situ ocean‐colour data. The algorithm performs better than those in which the Q factor is expressed as a function of chlorophyll‐a concentration alone.
Halos generated by negative cloud‐to‐ground lightning
Authors: Frey H. U. , Mende S. B. , Cummer S. A. , Li J. , Adachi T. , Fukunishi H. , Takahashi Y. , Chen A. B. , Hsu R.‐R. , Su H.‐T. , Chang Y.‐S.
Published: September 2007

The Imager for Sprites and Upper Atmospheric Lightning (ISUAL) on the FORMOSAT‐2 spacecraft observes Transient Luminous Events (TLE) like sprites, elves, and halos from space. We analyzed halos that were observed in Central America close enough to ELF/VLF receivers that allowed for the determination of the polarity of the parent lightning. All halos were created by negative cloud to ground lightning (−CG) strokes that occurred almost exclusively over the open water. Only three out of the 31 events happened over land. We conclude that the Central American region seems to be special with respect to the large proportion of −CG created halos. Such a behavior is very different from the occurrence of sprites that are mostly created by positive cloud to ground lightning.
An early Holocene sea‐level jump and delta initiation
Authors: Hori Kazuaki , Saito Yoshiki
Published: September 2007

Early Holocene sea‐level change controlled the evolution of clastic coastal depositional systems. Radiocarbon‐dated borehole cores obtained from three incised‐valley‐fill systems in Asia (Changjiang, Song Hong, and Kiso River) record very similar depositional histories, especially between about 9000 and 8500 cal BP. Sedimentary facies changes from estuarine sand and mud to shelf or prodelta mud suggest that the marine influence in the incised valleys increased during this period. In addition, large decreases in sediment accumulation rates occurred. A sea‐level jump causes an estuarine system and its depocenter to move rapidly landward. It is possible that the final collapse of the Laurentide Ice Sheet, accompanied by catastrophic drainage of glacial lakes, at approximately 8500 cal BP caused such a jump. The jump was followed immediately by a period of decelerated sea‐level rise that promoted delta initiation.
Nonlinearly generated plasma waves as a model for enhanced ion acoustic lines in the ionosphere
Authors: Daldorff L. K. S. , Pécseli H. L. , Trulsen J.
Published: September 2007

Observations from the EISCAT Svalbard Radar, for instance, demonstrate that the symmetry of the naturally occurring ion line can be broken by an enhanced, non‐thermal, level of fluctuations, i.e., Naturally Enhanced Ion‐Acoustic Lines (NEIALs). In a significant number of cases, the entire ion spectrum can be distorted, with the appearance of a third line, corresponding to a propagation velocity significantly below the ion acoustic sound speed. By numerical simulations, we consider one possible model accounting for the observations, suggesting that a primary process can be electron acoustic waves excited by a cold electron beam. Subsequently, an oscillating two‐stream instability excites electron plasma waves which in turn decay to asymmetric ion lines. Our code solves the full Vlasov equation for electrons and ions, with the dynamics coupled through the electrostatic field derived from Poisson's equation.
Electron dynamics and cross‐shock potential at the quasi‐perpendicular Earth's bow shock
Authors: Lefebvre Bertrand , Schwartz Steven J. , Fazakerley Andrew F. , Décréau Pierrette
Published: September 2007

The evolution of the electron distribution function through quasi‐perpendicular collisionless shocks is believed to be dominated by the electron dynamics in the large‐scale coherent and quasi‐stationary magnetic and electric fields. We investigate the electron distributions measured on board Cluster by the Plasma Electron and Current Experiment (PEACE) instrument during three quasi‐perpendicular bow shock crossings. Observed distributions are compared with those predicted by electron dynamics resulting from conservation of the first adiabatic invariant and energy in the de Hoffmann‐Teller frame, for all pitch angles and all types of trajectories (passing and, for the first time, reflected or trapped). The predicted downstream velocity distributions are mapped from upstream measurements using an improved Liouville mapping technique taking into account the overshoots. Furthermore, for one of these crossings we could take advantage of the configuration of the Cluster quartet to compare mapped upstream velocity distributions with those simultaneously measured at a relatively well magnetically connected downstream location. Consequences of energy and adiabatic invariant conservation are found to be compatible with the observed electron distributions, confirming the validity of electron “heating” theories based on DC fields as zeroth‐order approximations, but some systematic deviations are found between the dynamics of low‐ and high‐adiabatic invariant electrons. Our approach also provides a way to estimate the cross‐shock electric potential profile making full use of the electron measurements, and the results are compared to other estimates relying on the steady state dissipationless electron fluid equations. At the temporal resolution of the instruments, the scales associated to the change of the potential generally appear to be comparable to those of the magnetic field, but some differences between the methods appear within the shock transition. It is argued that potentials evaluated from Liouville mapping rely on less restrictive hypotheses and are therefore more reliable. Finally, we show how, in contrast to methods using electron velocity moments, the technique can be used to produce high‐time‐resolution electric potentials and discuss the electric potential profiles through the shock.
Statistical significance of association between whistler‐mode chorus enhancements and enhanced convection periods during high‐speed streams
Authors: Hwang J. A. , Lee D.‐Y. , Lyons L. R. , Smith A. J. , Zou S. , Min K. W. , Kim K.‐H. , Moon Y.‐J. , Park Y. D.
Published: September 2007

During high‐speed solar wind streams, substorms occur repetitively and relativistic electron fluxes enhance significantly. It has recently been proposed that enhanced dawnside chorus waves lead to the energization of the relativistic electrons and that they are associated with the periods of enhanced convection that precede substorm expansions, rather than with the expansions themselves. In this paper, we have evaluated the statistical significance of this association using a total of 657 substorms during high‐speed solar wind streams observed by the ACE spacecraft and whistler‐mode chorus waves observed from the VLF/ELF Logger Experiment (VELOX) at Halley station, Antarctica. We find that ∼66% of the substorm events identified at 0400–1400 MLT show the association with the chorus enhancement that starts to increase ∼35 min, on average, prior to substorm onsets and remains elevated until declining back to near the preenhancement level in ∼16 min, on average, after substorm onsets. Our statistical results suggest that a large number of the chorus wave enhancements at dawn to postnoon local times occur during the enhanced convection period of the substorm growth phase. This is distinguished from the chorus wave enhancement near midnight that is caused by substorm‐injected electrons after onsets. We find that ∼59% of the events identified at 2200–0200 MLT show chorus enhancements that start on average ∼6 min after substorm onsets and remain elevated for ∼32 min on average.
Physical basis of generalized potential temperature and its application to cyclone tracks in nonuniformly saturated atmosphere
Authors: Gao Shouting , Cao Jie
Published: September 2007

This paper presents the physical basis and the conservation property of the generalized potential temperature θ* from the first law of thermodynamics. Here θ* is defined when the commonly used step function is replaced by a smooth function of relative humidity to some power. This new variable, which includes the weighting function acting as a condensation probability factor in the expression of specific humidity, may be more appropriate to describe the property of nonuniform saturation of the real atmosphere. Generalized moist potential vorticity (GMPV), defined as αζa · ∇θ* as expressed by Gao et al. (2004) (α is the specific volume and ζa is the absolute vorticity), is studied theoretically on its application to trace cyclones. It is shown through a case study that cyclone tracks can be well represented by the low negative GMPV centers. Thus the GMPV anomaly may be used as an alternative tool to the traditional use of surface pressure in cyclone tracks and to make a short‐term prediction. What is more, other potential usages of GMPV are also pointed out in this study.
Biomarker method validation in anticancer drug development
Authors: Cummings J , Ward T H , Greystoke A , Ranson M , Dive C
Published: September 2007

Over recent years the role of biomarkers in anticancer drug development has expanded across a spectrum of applications ranging from research tool during early discovery to surrogate endpoint in the clinic. However, in Europe when biomarker measurements are performed on samples collected from subjects entered into clinical trials of new investigational agents, laboratories conducting these analyses become subject to the Clinical Trials Regulations. While these regulations are not specific in their requirements of research laboratories, quality assurance and in particular assay validation are essential. This review, therefore, focuses on a discussion of current thinking in biomarker assay validation. Five categories define the majority of biomarker assays from ‘absolute quantitation’ to ‘categorical’. Validation must therefore take account of both the position of the biomarker in the spectrum towards clinical end point and the level of quantitation inherent in the methodology. Biomarker assay validation should be performed ideally in stages on ‘a fit for purpose’ basis avoiding unnecessarily dogmatic adherence to rigid guidelines but with careful monitoring of progress at the end of each stage. These principles are illustrated with two specific examples: (a) absolute quantitation of protein biomarkers by mass spectrometry and (b) the M30 and M65 ELISA assays as surrogate end points of cell death.

British Journal of Pharmacology (2008) 153, 646–656; doi:10.1038/sj.bjp.0707441; published online 17 September 2007
Cardioprotection: spotlight on PKG
Authors: Cohen M V , Downey J M
Published: September 2007

Classical ischaemic preconditioning, delayed or second window preconditioning and postconditioning are forms of cardioprotection that are dependent on cell surface receptors, intracellular signalling molecules and kinases that ultimately block formation of the mitochondrial permeability transition. The latter is presumed to cause myocardial necrosis as well as apoptosis, so prevention of its formation upon resumption of perfusion after a prolonged coronary occlusion should be cardioprotective. In all of these forms of cardioprotection, formation of cGMP and activation of protein kinase G (PKG) are recognized to be key steps in the signal transduction pathway. Burley et al. highlight the roles of cGMP and PKG in their comprehensive review. They describe the basic biology of PKG and emphasize its compartmentalization, which may be responsible for the frustration induced by assays for PKG in whole cell lysates and for the spurious conclusions about the role of PKG in cardioprotection. This review will be useful to both the novice and the seasoned investigator.

British Journal of Pharmacology (2007) 152, 833–834; doi:10.1038/sj.bjp.0707453; published online 17 September 2007
Store‐operated calcium entry in vascular smooth muscle
Authors: Leung F P , Yung L M , Yao X , Laher I , Huang Y
Published: September 2007

In non‐excitable cells, activation of G‐protein‐coupled phospholipase C (PLC)‐linked receptors causes the release of Ca2+from intracellular stores, which is followed by transmembrane Ca2+entry. This Ca2+entry underlies a small and sustained phase of the cellular [Ca2+]iincreases and is important for several cellular functions including gene expression, secretion and cell proliferation. This form of transmembrane Ca2+entry is supported by agonist‐activated Ca2+‐permeable ion channels that are activated by store depletion and is referred to as store‐operated Ca2+entry (SOCE) and represents a major pathway for agonist‐induced Ca2+entry. In excitable cells such as smooth muscle cells, Ca2+entry mechanisms responsible for sustained cellular activation are normally considered to be mediated via either voltage‐operated or receptor‐operated Ca2+channels. Although SOCE occurs following agonist activation of smooth muscle, this was thought to be more important in replenishing Ca2+stores rather than acting as a source of activator Ca2+for the contractile process. This review summarizes our current knowledge of SOCE as a regulator of vascular smooth muscle tone and discusses its possible role in the cardiovascular function and disease. We propose a possible hypothesis for its activation and suggest that SOCE may represent a novel target for pharmacological therapeutic intervention.

British Journal of Pharmacology(2008)153, 846–857; doi:10.1038/sj.bjp.0707455; published online 17 September 2007
The complications of promiscuity: endocannabinoid action and metabolism
Authors: Alexander S P H , Kendall D A
Published: September 2007

In this review, we present our understanding of the action and metabolism of endocannabinoids and related endogenous molecules. It is clear that the interactions between the multiple endocannabinoid‐like molecules (ECLs) are highly complex, both at the level of signal transduction and metabolism. Thus, ECLs are a group of ligands active at 7‐transmembrane and nuclear receptors, as well as transmitter‐gated and ion channels. ECLs and their metabolites can converge on common endpoints (either metabolic or signalling) through contradictory or reinforcing pathways. We highlight the complexity of the endocannabinoid system, based on the promiscuous nature of ECLs and their metabolites, as well as the synthetic modulators of the endocannabinoid system.

British Journal of Pharmacology(2007)152, 602–623; doi:10.1038/sj.bjp.0707456; published online 17 September 2007
The orphan receptor GPR55 is a novel cannabinoid receptor
Authors: Ryberg E , Larsson N , Sjögren S , Hjorth S , Hermansson N‐O , Leonova J , Elebring T , Nilsson K , Drmota T , Greasley P J
Published: September 2007

Background:

The endocannabinoid system functions through two well characterized receptor systems, the CB1 and CB2 receptors. Work by a number of groups in recent years has provided evidence that the system is more complicated and additional receptor types should exist to explain ligand activity in a number of physiological processes.

Experimental approach:

Cells transfected with the human cDNA for GPR55 were tested for their ability to bind and to mediate GTPγS binding by cannabinoid ligands. Using an antibody and peptide blocking approach, the nature of the G‐protein coupling was determined and further demonstrated by measuring activity of downstream signalling pathways.

Key results:

We demonstrate that GPR55 binds to and is activated by the cannabinoid ligand CP55940. In addition endocannabinoids including anandamide and virodhamine activate GTPγS binding via GPR55 with nM potencies. Ligands such as cannabidiol and abnormal cannabidiol which exhibit no CB1or CB2 activity and are believed to function at a novel cannabinoid receptor, also showed activity at GPR55. GPR55 couples to Gα13 and can mediate activation of rhoA, cdc42 and rac1.

Conclusions:

These data suggest that GPR55 is a novel cannabinoid receptor, and its ligand profile with respect to CB1 and CB2 described here will permit delineation of its physiological function(s).

British Journal of Pharmacology (2007) 152, 1092–1101; doi:10.1038/sj.bjp.0707460; published online 17 September 2007
A vehicle overtaking model of traffic dynamics
Authors: Jamison S. , McCartney M.
Published: September 2007

Mathematical models that describe the dynamical behavior of a group of vehicles as they move along a stretch of road are known as car following models. They attempt to model the interactions between individual vehicles where the behavior of each vehicle is dependent on the motion of the vehicle directly in front and overtaking is not permitted. In this paper, the traditional car following model is modified by removing this “no overtaking” restriction and its behavior is investigated for a group of vehicles traveling on a closed loop. The resulting model is described in terms of a set of coupled time delay differential equations, and these are solved numerically to analyze their post transient behavior under a periodic perturbation. The effect of varying both the time taken for the driver to respond to the behavior of the vehicle in front and the length of the closed loop is examined. For certain parameter choices, the post transient behavior is found to be chaotic, and in these cases the degree of chaos is estimated using the Grassberger-Procaccia dimension.
Dynamic simulation of the ion sheath in the presence of fast monoenergetic electrons
Authors: Sharifian M. , Shokri B.
Published: September 2007

This paper contains interesting simulation results concerning the nonstationary potential distribution inside the sheath formed between a plasma and a biased electrode in the presence of a fast group of electrons. The influence of these fast monoenergetic electrons on the ion dynamics of a planar sheath is investigated assuming that the ion, electron, and fast electron components act as three coupled fluids. Under collision-free conditions and in the presence of a fast electron beam, the evolution of the potential and ion density distribution as a function of length is found. These profiles show that in the plasma with a group of fast monoenergetic electrons, a nonmonotonic distribution of the potential could be formed in front of the cathode in which its maximum is larger than the biased electrode potential with the passage of time. Results indicate that the formation of this maximum potential depends strongly on the ratio of the density of non-Maxwellian (fast) electrons to the density of the Maxwellian (plasma bulk) electrons.
On the security of a spatiotemporal chaotic cryptosystem
Authors: Rhouma Rhouma , Safya Belghith
Published: September 2007

Recently, Tang et al. [Phys Lett. A 318, 388 (2003)] proposed a spatiotemporal cryptosystem based on one-way coupled map lattices. They claim that it has high security, fast encryption speed, and short synchronization transient. This work proves that this scheme has some security weaknesses. Indeed, we propose an attack which the system cannot withstand.
Adaptive complete synchronization of chaotic dynamical network with unknown and mismatched parameters
Authors: Xiao Yuzhu , Xu Wei , Li Xiuchun , Tang Sufang
Published: September 2007

In this paper, an adaptive controller is designed to synchronize the chaotic dynamical network with unknown and mismatched parameters. Based on the invariance principle of differential equations, some generic sufficient conditions for asymptotic synchronization are obtained. In order to demonstrate the effectiveness of the proposed method, an example is provided and numerical simulations are performed. The numerical results show that our control scheme is very effective and robust against the weak noise.
Role of van der Waals resonances in the vibrational relaxation of HF by collisions with H atoms
Authors: Tao Liang , Alexander Millard H.
Published: September 2007

Vibrational relaxation of HF(v) in collisions with H atoms can occur by three pathways: inelastic scattering with and without H atom exchange, and, for v⩾3, the HF+H→F+H2 reaction. Fully quantum, reactive scattering calculations on the Stark-Werner FH2 potential energy surface reveal narrow peaks in the energy dependence of the integral cross sections for each of these processes. By means of an adiabatic-bender analysis, we show that each of these peaks corresponds to the position of quasibound HF-H vibrational states trapped in the weak van der Waals well. The width of these resonances indicates that the lifetime of the quasibound states is up to 30 periods of the HF-H van der Waals vibration.
Effect of oxidation on the wettability of poly(dimethylsiloxane) surfaces
Authors: Schneemilch M. , Quirke N.
Published: September 2007

The wetting of amorphous poly(dimethylsiloxane) (PDMS) surfaces by water has been studied using molecular dynamics simulations. PDMS surfaces were generated by compressing a long PDMS chain between two elastic boundaries at atmospheric pressure. Oxidation of the PDMS surface, achieved in real systems by exposure to air plasma or corona discharge, was modeled by replacing methyl groups on the PDMS chain with hydroxyl groups. Three surfaces of varying degrees of oxidation were characterized by measuring the water contact angle and the roughness. The dependence of the microscopic contact angle on drop size was measured from time averaged density profiles. The macroscopic contact angle was measured directly using a cylindrical drop of infinite length with zero contact line curvature. The measured macroscopic contact angle ranged from approximately 125° on the untreated surface to 75° on the most oxidized surface studied. The line tension was found to increase with increasing degree of oxidation, from a negligible value on the untreated surface to approximately 5×10−11Jm−1 on the most heavily oxidized surface.
Scanning tunneling spectroscopy of inhomogeneous electronic structure in monolayer and bilayer graphene on SiC
Authors: Brar Victor W. , Zhang Yuanbo , Yayon Yossi , Ohta Taisuke , McChesney Jessica L. , Bostwick Aaron , Rotenberg Eli , Horn Karsten , Crommie Michael F.
Published: September 2007

The authors present a scanning tunneling spectroscopy (STS) study of the local electronic structure of single and bilayer graphene grown epitaxially on a SiC(0001) surface. Low voltage topographic images reveal fine, atomic-scale carbon networks, whereas higher bias images are dominated by emergent spatially inhomogeneous large-scale structure similar to a carbon-rich reconstruction of SiC(0001). STS spectroscopy shows an ∼100meV gaplike feature around zero bias for both monolayer and bilayer graphene/SiC, as well as significant spatial inhomogeneity in electronic structure above the gap edge. Nanoscale structure at the SiC/graphene interface is seen to correlate with observed electronic spatial inhomogeneity. These results are relevant for potential devices involving electronic transport or tunneling in graphene/SiC.
Characteristics of the wavelength of ripples on icicles
Authors: Ueno K.
Published: September 2007

It is known that the wavelength of the ripples on icicles in nature is of the centimeter scale. Such study on morphological instability of ice-water interface during ice growth from flowing supercooled water film with one side being a free surface has recently been made [K. Ueno, Phys. Rev. E 68, 021603 (2003)]. This is the first theoretical study taking into account the influence of the shape of the water-air surface on the growth condition of infinitesimal disturbances of the ice-water interface. A simpler formula to determine the wavelength of the ripples than that in the previous paper is derived. It seems that the wavelength of ripples is insensitive to the water supply rates, diameters of the icicles, and surrounding air temperatures. The details of dependence of the wavelength of ripples on these parameters are investigated.
Intense gigawatt relativistic electron beam generation in the presence of prepulse. Part II
Authors: Roy Amitava , Mondal J. , Menon R. , Mitra S. , Kumar D. D. P. , Sharma Archana , Mittal K. C. , Nagesh K. V. , Chakravarthy D. P.
Published: September 2007

Intense relativistic electron beam diode has been operated without a prepulse switch. Our previously reported results demonstrated that the large pulse power systems in the presence of prepulse can deliver gigawatt power pulses into a matched load if the anode cathode gap is set larger than that estimated by the Child Langmuir relation. This article reports some more experimental results on the current and voltage characteristics, the shot to shot reproducibility of the diode in the presence of prepulse. Intense electron beam diode behavior was studied for various anode cathode gaps and voltages in presence of prepulse. It has been observed that for small gap, prepulse generated plasma completely fills the anode cathode gap and the diode behaves as plasma filled diode. At a large gap the beam parameters obtained are 420 keV, 22 kA, 100 ns. From the experimentally obtained values of perveance an upper limit was set up for the Marx voltage (or anode cathode voltage) and lower limit for the anode cathode gap in order to avoid the gap closure problem and the diode can be operated with a better shot to shot reproducibility.
Conformational degree and molecular orientation in rubrene film by in situ x-ray absorption spectroscopy
Authors: Wang Li , Chen Shi , Liu Lei , Qi Dongchen , Gao Xingyu , Subbiah Jegadesan , Swaminathan Sindhu , TS Wee Andrew
Published: September 2007

The conformation degree and molecular orientation during the growth of rubrene films on Si(111) and Au(111) have been studied by in situ x-ray absorption spectroscopy. The backbones of rubrene molecules on Au(111) are twisted at the first few layers; in contrast, no appreciable twisting is observed on Si(111) even at a thickness of approximately 1.5 nm. The planarization of the backbone in the first few layers is due to strong molecule–substrate interactions between rubrene and Si(111). The rubrene molecules on Au(111) have a backbone tilt angle of 41° and a phenyl side group tilt of 64° with respect to the substrate surface, suggesting the crystalline nature of the films. Ex situ atomic force microscopy measurements confirm that the rubrene film grown on Au(111) is crystalline and the growth direction is along its crystallographic c axis.
Two-detector measurement system of pulse photothermal radiometry for the investigation of the thermal properties of thin films
Authors: Martan J. , Hervé O. , Lang V.
Published: September 2007

Pulsed photothermal radiometry, a method developed in previous work for thin film thermal effusivity measurements, is now further developed for the determination of thin film thermal conductivity and volumetric specific heat. The present setup consists of a nanosecond laser source and two infrared (IR) detectors for temperature response measurement. The two detectors have different sizes and frequency bandwidths enabling accurate measurement of the surface temperature both in very short (ns) and long (μs) times after the laser pulse. This enables measurement of the apparent effusivity of both the thin film and substrate. The position in time of the transition region between the film and substrate effusivity is essential for recalculation of the thermal conductivity and volumetric specific heat from the measured thermal effusivity. The presented experimental system was applied to the investigation of the thermal properties of TiO2 and Si-B-C-N thin films. The different thermal conductivity of the TiO2 films correlates well with their different phase structures. The Si-B-C-N films show a slightly different thermal conductivity and specific heat capacity for different atomic compositions.
Characterization of nitrogen-doped Sb2Te3 films and their application to phase-change memory
Authors: Yin You , Sone Hayato , Hosaka Sumio
Published: September 2007

In this study, sputtered undoped and nitrogen doped Sb2Te3 (ST and STN) films were systematically investigated by x-ray diffraction (XRD) and resistance measurements. Their application to lateral phase-change memory (PCM) is presented as well. The STN film sputtered at a flow rate ratio (N2∕Ar) of 0.07 proved to have both high stability and low power consumption, implying its high performance in PCM applications. In the STN films (N2∕Ar>0.15), the hexagonal Te phase first appeared at 160 °C, and then the orthorhombic SbN phase appeared at 290 °C. The phase separation made it very difficult for these films to switch reversibly between the crystalline and the amorphous phase.
Advanced nanoimprint lithography using a graded functional imprinting material tailored for liquid crystal alignment
Authors: Gwag Jin Seog , Oh-e Masahito , Yoneya Makoto , Yokoyama Hiroshi , Satou H. , Itami S.
Published: September 2007

Nanoimprint lithography technology, which is able to easily create nanometer-resolution two-dimensional surface grooves on substrates over a large area by a step and stamp process, opens up an intriguing opportunity for functional liquid crystal (LC) alignment. We describe here a hybrid polymer consisting of two distinct moieties with largely different thermomechanical properties and surface activity. We present the results of nanoimprint lithography experiment using the hybrid polymer to demonstrate the practical applicability as an LC alignment layer. This material shows excellent capability both as a nanoimprinting material, requiring softness at moderate temperatures, and as a LC alignment layer, requiring sufficient rigidity. LC devices using the alignment layer show fairly stable electro-optic characteristics even after thermal aging, due to its high thermal stability. The soft component of the hybrid polymer helps it provide the multiple imprinting capabilities at higher temperatures virtually without any mold damages.