bluuebunny/crossref_metadata_2025 huggingface dataset:
Field thermal monitoring during the August 2003 eruption at Piton de la Fournaise (La Réunion)
Authors: Coppola Diego , Staudacher Thomas , Cigolini Corrado
Published: May 2007

A detailed set of thermal images collected during the last day of the August 2003 eruption of Piton de la Fournaise (La Réunion), clearly revealed several dynamic processes associated with a spatter cone containing a lava pond and feeding a channelized lava flow. Periods of steady effusion were interrupted by brief pulses of lava effusion that closely coincide with peaks in seismic tremor amplitude. The thermal measurements show that roofing of a lava channel during steady effusion and cooling of surface flows decrease thermal radiance in two different ways. Here we show that the decrease in thermal radiance because of channel roofing is not related to a decrease in volcanic activity, as might be interpreted from satellite data. In addition, we introduce a new method of representing thermal data (hereby named “Radiative Thermogramme”) that successfully describes thermal patterns produced by distinct eruptive processes within the same span of time. This graphic solution can be directly correlated with volcanic field processes and provides a useful tool for interpreting a high number of thermal data in a wide range of volcanic activities.
Influences of urban fabric on pyroclastic density currents at Pompeii (Italy): 2. Temperature of the deposits and hazard implications
Authors: Zanella E. , Gurioli L. , Pareschi M. T. , Lanza R.
Published: May 2007

During the A.D. 79 eruption of Vesuvius, Italy, the Roman town of Pompeii was covered by 2.5 m of pyroclastic fall pumice and then partially destroyed by pyroclastic density currents (PDCs). Thermal remanent magnetization measurements performed on the lithic and roof tile fragments embedded in the PDC deposits allow us to quantify the variations in the temperature (Tdep) of the deposits within and around Pompeii. These results reveal that the presence of buildings strongly influenced the deposition temperature of the erupted products. The first two currents, which entered Pompeii at a temperature around 300–360°C, show drastic decreases in the Tdep, with minima of 100–140°C, found in the deposits within the town. We interpret these decreases in temperature as being the result of localized interactions between the PDCs and the city structures, which were only able to affect the lower part of the currents. Down flow of Pompeii, the lowermost portion of the PDCs regained its original physical characteristics, emplacing hot deposits once more. The final, dilute PDCs entered a town that was already partially destroyed by the previous currents. These PDCs left thin ash deposits, which mantled the previous ones. The lack of interaction with the urban fabric is indicated by their uniform temperature everywhere. However, the relatively high temperature of the deposits, between 140 and 300°C, indicates that even these distal, thin ash layers, capped by their accretionary lapilli bed, were associated with PDCs that were still hot enough to cause problems for unsheltered people.
Intercomparison of multiaxis and long‐path differential optical absorption spectroscopy measurements in the marine boundary layer
Authors: Pikelnaya Olga , Hurlock Stephen C. , Trick Sebastian , Stutz Jochen
Published: May 2007

Multiaxis differential optical absorption spectroscopy (MAX‐DOAS) has many advantages that make it ideally suited for trace gas monitoring. MAX‐DOAS instruments can be relatively small, are easy to operate, and allow long‐term automated operation. The MAX‐DOAS technique also allows derivation of vertical aerosol and trace gas profiles in the troposphere and thus the monitoring of pollution aloft. However, this relatively new technique still requires validation to determine uncertainties, for example, introduced by the radiative transfer modeling needed to derive trace gas concentrations. Here we present MAX‐DOAS measurements of NO2 and HCHO performed in the Gulf of Maine during the ICARTT campaign in summer 2004. O4 measurements were performed to gain information on the vertical distribution of aerosols, which were used in radiative transfer calculations to convert the measured trace gas slant column densities to concentrations. The successful identification of an aerosol layer between 1 and 2 km altitude illustrates the potential for aerosol remote sensing. The comparison with LP DOAS measurements performed simultaneously shows that MAX‐DOAS accurately measures trace gases that are well mixed within the boundary layer. MAX‐DOAS measurements also provide valuable information on the vertical distribution of pollutants in and above the boundary layer, as demonstrated by the identification of elevated HCHO levels in a layer between 1 km and 2 km altitude. This phenomenon, which is associated with outflow of continental air from the American northeast, was not detected by in situ ground‐based instruments.
Sensitivity of the boreal winter circulation in the middle atmosphere to the quasi‐biennial oscillation in MAECHAM5 simulations
Authors: Calvo N. , Giorgetta M. A. , Peña‐Ortiz C.
Published: May 2007

The polar vortex in the Northern Hemisphere exhibits high intraseasonal and interannual variability which, to some degree, may be controlled by the quasi‐biennial oscillation (QBO) in the tropical stratosphere. Here we analyze the QBO signal in the Northern Hemisphere polar vortex in a model simulation using the general circulation model MAECHAM5 (Middle Atmosphere European Center Hamburg Model), which simulates the QBO as an internal mode of variability. Composites have been computed for the westerly and easterly QBO phases from early winter to late winter (November–December, December–January and January–February) of a 50‐year experiment containing 20 complete QBO cycles. This method identifies tropical and midlatitude patterns in wind and temperature that are related to the secondary meridional circulation of the QBO extending towards the winter pole. In the tropics, significant QBO signature is observed in the mesosphere up to 0.05 hPa only in early winter and mainly in the easterly QBO phase forced by the parameterized gravity waves‐mean flow interaction. At high latitudes, MAECHAM5 shows a significantly warmer (colder) polar stratosphere in the easterly (westerly) QBO phase at 30 hPa accompanied by a weaker (stronger) polar vortex in the late winter months, from December to February (December to January) in the easterly (westerly) phase of the QBO. In early winter there is no significant change in temperature and zonal mean zonal wind in the polar stratosphere. The analysis of EP fluxes shows a different behavior between QBO phases, with changes in the waveguide. Wave propagation occurs upwards and polewards in the easterly QBO phase at 30 hPa, while waves are refracted equatorward in the westerly phase. No relationship has been found between the tropical QBO and the final warming at the end of the boreal winter.
Latitude‐dependent long‐term variations in polar mesospheric clouds from SBUV version 3 PMC data
Authors: DeLand Matthew T. , Shettle Eric P. , Thomas Gary E. , Olivero John J.
Published: May 2007

Previous studies have suggested that there should be secular trends in polar mesospheric cloud (PMC) occurrence frequency and brightness on decadal timescales and that those trends would be strongest at the lowest latitudes of the PMC existence region. We have analyzed the 27‐year PMC data set created from Solar Backscatter Ultraviolet (SBUV, SBUV/2) satellite instruments for long‐term variations in albedo using three latitude bands (50°–64°, 64°–74°, 74°–82°). The improved version 3 data set includes revisions to the PMC detection algorithm to produce more consistent results in all measurement conditions. A detailed error analysis yields an approximate uncertainty of 1–2% for seasonally averaged 252‐nm albedo values. Adjustments for local time variations in PMC brightness between different satellite data sets were derived to ensure accurate trend calculations. Multiple linear regression fits show that albedo variations are anticorrelated with solar activity in all latitude bands, with a stronger response at high latitudes. The albedo increase from solar maximum to solar minimum ranges from +2% at 50°–64°S to +17% at 74°–82°N. Secular trends in albedo are positive, with long‐term changes over 27 years ranging from +12% to +20% depending on hemisphere and latitude. The derived long‐term trend in PMC albedo at 50°–64° is smaller than that of higher latitudes. This result contradicts previous suggestions that PMC brightness changes might be most rapid at low latitudes. The albedo response to solar variations is larger in the Northern Hemisphere, while long‐term trends are approximately the same in both hemispheres.
Evolution of surface ozone in central Italy based on observations and statistical model
Authors: Di Carlo Piero , Pitari Giovanni , Mancini Eva , Gentile Sabrina , Pichelli Emanuela , Visconti Guido
Published: May 2007

Hourly and daily variations of surface ozone have been analyzed in relation to radon and meteorological parameters to explore its controlling mechanisms. Measurements in central Italy cover the years 2004 and 2005, showing a relevant role of transport in the ozone concentration variability. An analysis based on back trajectories shows that the site is affected by air masses originating from the west to northeast sector in about 74% of the days, suggesting that L’Aquila could be considered a background site. The background hypothesis is also supported by the rather low values of the following ozone quantities: maximum of monthly averages (39 ppbv, July), annual median of hourly data (29 ppbv), and annual average of hourly maxima recorded daily (49 ppbv). Only six hourly data recorded ozone above 90 ppbv in 2 years but never above 100 ppbv. The regression model reproduces measured ozone with accuracy in 67% of hourly observations and 74% of daily mean data. Here the model includes information from the following meteorological parameters: temperature, relative humidity, horizontal wind speed/direction, sun radiation, and radon concentration. A tracer like radon that tracks the dynamical changes of the lower atmosphere has a significant role in the model ozone prediction improvement, especially for hourly observations and for the synoptic component. In the first case (hourly observation), inclusion of radon data improves the regression model performance by 5% (from 62 to 67%); in the last case (synoptic component), the model accuracy increases by 3% (from 78 to 81%).
Morphology, chemistry, and spectral properties of Hawaiian rock coatings and implications for Mars
Authors: Minitti Michelle E. , Weitz Catherine M. , Lane Melissa D. , Bishop Janice L.
Published: May 2007

We studied coatings on five glass‐rich basalts from the Big Island of Hawaii. The coatings are characterized by complex morphologies and their thicknesses range from 3 to 80 μm. Coating chemistries are predominantly hydrated silica with minor amounts of Fe‐, Ti‐, and S‐bearing materials. Visible, near infrared, and thermal infrared spectra of the coatings demonstrate that coatings as thin as 3 μm mask the spectral character of the substrate basalt. The Fe‐, Ti‐, and S‐bearing components control the VNIR coating spectra. The hydrated silica component of the coatings dominates the thermal infrared coating spectra. The coating chemistries are consistent with leaching and/or dissolution of basalt glass or tephra in aqueous, acidic, and oxidizing conditions and subsequent precipitation of insoluble phases. Similar alteration conditions are thought to have occurred on Mars, making formation of such coatings on Martian lithologies feasible. Given the capabilities of various Mars missions, if coatings like those of this study were present on Martian lithologies, their chemical and/or spectral signatures would be detectable. Chemical and spectral data from thin (≤10 μm), Fe‐ and Ti‐bearing coatings are consistent with phases capable of explaining the high‐SiO2 component of Type 2 surfaces previously identified in the Thermal Emission Spectrometer data set and are potentially consistent with spectral data from the Mars Exploration Rovers.
Coherent obliquity band and heterogeneous precession band responses in early Pleistocene tropical sea surface temperatures
Authors: Cleaveland Laura C. , Herbert Timothy D.
Published: May 2007

The nature of the connection between high‐ and low‐latitude climates during the early Pleistocene “41 kyr world” has important implications for our understanding of the feedbacks involved in translating insolation changes into global climate states. Here we focus on the tropical marine record, presenting alkenone‐derived sea surface temperature (SST) and productivity records from the eastern equatorial Atlantic, eastern equatorial Pacific, the Arabian Sea, and the South China Sea for a time interval covering the heart of the 41 kyr world (1.2–2.0 Ma). All four SST records are dominated by variance in the obliquity band, suggesting that high‐latitude dynamics and low‐latitude climate were tightly coupled in the 41 kyr world, despite smaller ice volume variability during this interval as compared to the late Pleistocene. At the 41 kyr period, SST varied coherently and nearly synchronously between the four study regions, suggesting a tropic‐wide feedback to high‐latitude processes. Productivity variations at our equatorial Atlantic and Pacific sites were also coherent in the obliquity band, implying tropical trade wind variability at this frequency during the early Pleistocene. In contrast, we observe heterogeneous SST and productivity responses in the precession band between each of the tropical locations. Local atmospheric circulation patterns, rather than a globally coordinated response to precessional insolation forcing, apparently determined SSTs and productivity in the tropics at precessional frequencies during the early Pleistocene.
ULF Doppler oscillations in the low latitude ionosphere
Authors: Menk Frederick W. , Waters Colin L. , Dunlop Ian S.
Published: May 2007

An array of magnetometers and Doppler sounders spanning L = 1.56–2.77 was used to examine perturbations in the daytime ionosphere driven by downgoing ULF waves. For frequencies away from the local field line resonance (FLR), the waves caused mostly vertical motions of the F‐region plasma with amplitude ∼0.03–0.06 Hz/nT, with a phase delay of 30° to 40° at the ground. At the local resonant frequency and harmonics the amplitude and phase delay increased markedly. We modeled this by considering an admixture of ULF wave modes and oblique magnetic field geometry, and using actual ionospheric parameters. The model results agree well with observations when the downgoing wave mode varies smoothly from pure fast mode away from the resonance to mostly transverse mode at resonance. These results provide new information on the interaction between downgoing ULF waves and the ionospheric plasma.
Classification of pre‐eruption and non‐pre‐eruption epochs at Mount Etna volcano by means of artificial neural networks
Authors: Castellaro Silvia , Mulargia Francesco
Published: May 2007

We apply artificial neural networks to the classification of pre‐eruption time epochs of Mount Etna volcano on the basis of variables depending on tectonics and on the volcano ‘recharging system’. We consider time‐epochs from 7 to 30 days and train the supervised nets, with the aim of recognizing the time epochs preceding summit eruptions, lateral eruptions and not preceding any eruption. Tested on a number of independent data sets, these patterns are found to be efficient (75 ± 10% success) in recognizing pre‐summit eruption epochs, while distinguishing pre‐lateral from non‐pre‐eruption epochs is impossible. We then apply non‐supervised algorithms to the whole set of data obtaining a confirmation of the findings of supervised nets. This difficulty in recognizing patterns characteristic of pre‐lateral eruption epochs is at odds with all previous work and seems to depend on the small size of the eruptive series, which makes unstable the results of any multivariate analysis.
Smooth electron density transition from plasmasphere to the subauroral region
Authors: Tu Jiannan , Song Paul , Reinisch Bodo W. , Green James L.
Published: May 2007

Upper hybrid resonance (UHR) noise band and the nonthermal continuum (NTC) radiation were routinely observed by the radio plasma imager (RPI) onboard the IMAGE satellite when it transited the plasmasphere and subauroral regions. The lower cutoff frequencies of the UHR band and the NTC radiation provide an estimate of the electron plasma frequencies along the satellite orbit. A steep electron density gradient, which defines the plasmapause, was commonly observed when IMAGE transited from the plasmasphere to the subauroral region or vice versa. It appears however that, on many occasions, the electron density transition from the plasmasphere to the subauroral region is smooth without a clear signature of the plasmapause. Such smooth transitions can occur at various magnetic local times. The events presented in this study were observed after geomagnetic activities had been quiet for 2 or more days with Kp primarily less than 3. The smooth density transitions from the plasmasphere to the subauroral region may be an observational evidence of the suggested plasmaspheric wind.
Significant depletions of the ionospheric plasma density at middle latitudes: A possible signature of equatorial spread F bubbles near the plasmapause
Authors: Huang Chao‐Song , Foster John C. , Sahai Yogeshwar
Published: May 2007

Plasma density irregularities in the equatorial F region ionosphere are generally called equatorial spread F (ESF). Large‐scale plasma bubbles associated with ESF processes are generated in the bottomside F region and penetrate the F peak to the topside F region. It is still not fully understood how high ESF bubbles can reach. In this paper, we present the measurements of deep depletions of the ionospheric plasma density at 840‐km altitude with the Defense Meteorological Satellite Program (DMSP) satellites in the evening sector on 29 October 2003. The plasma depletions occurred after an interval of strong southward interplanetary magnetic field (IMF). A prominent feature of the observations is that the plasma depletions occurred at very high magnetic latitudes (MLAT), as well as at equatorial latitudes. The equatorial depletions were identified as plasma bubbles. The depletions at middle latitudes (20°–46° MLAT) were separated from the conventional ionospheric midlatitude trough and identified as the extension of ESF flux tubes into these latitudes. It implies that the plasma bubble, which caused the emptied flux tube at 46° MLAT, reached the altitude of 6800 km over the magnetic equator. The observations may represent the highest altitude/latitude of plasma bubbles that has ever been reported in the literature. For the plasma depletions at even higher latitudes (47°–49° MLAT) near the subauroral polarization stream (SAPS)/midlatitude trough, there are two candidate generation mechanisms. One is the extension of ESF flux tubes into these latitudes, implying that the plasma bubbles reached the altitude of 8400 km over the magnetic equator. Because the SAPS/midlatitude trough corresponds to the plasmapause at the plasmaspheric heights, the observations suggest that ESF plasma bubbles may have reached the plasmapause. Another mechanism is a field‐aligned, low‐density structure between the plasmasphere and ionosphere, and the plasma structure is generated through the strong electric field in the subauroral polarization stream region.
Mutations at F637 in the NMDA receptor NR2A subunit M3 domain influence agonist potency, ion channel gating and alcohol action
Authors: Ren H , Salous A K , Paul J M , Lipsky R H , Peoples R W
Published: May 2007

Background and purpose:

NMDA receptors are important molecular targets of ethanol action in the CNS. Previous studies have identified a site in membrane‐associated domain 3 (M3) of the NR1 subunit and two sites in M4 of the NR2A subunit that influence alcohol action; the sites in NR2A M4 also regulate ion channel gating. The purpose of this study was to determine whether mutations at the site in the NR2A subunit corresponding to the NR1 M3 site influence alcohol action and ion channel gating.

Experimental approach:

We investigated the effects of mutations at phenylalanine (F) 637 of the NR2A subunit using whole‐cell and single‐channel patch‐clamp electrophysiological recording in transiently‐transfected HEK 293 cells.

Key results:

Mutations at F637 in the NR2A subunit altered peak and steady‐state glutamate EC50 values, maximal steady‐state to peak current ratios (Iss:Ip), mean open time, and ethanol IC50 values. Differences in glutamate potency among the mutants were not due to changes in desensitization. Ethanol IC50 values were significantly correlated with glutamate EC50 values, but not with maximal Iss:Ip or mean open time. Ethanol IC50 values were linearly and inversely related to molecular volume of the substituent.

Conclusions and implications:

These results demonstrate that NR2A(F637) influences NMDA receptor affinity, ion channel gating, and ethanol sensitivity. The changes in NMDA receptor affinity are likely to be the result of altered ion channel gating. In contrast to the cognate site in the NR1 subunit, the action of ethanol does not appear to involve occupation of a critical volume at NR2A(F637).

British Journal of Pharmacology (2007) 151, 749–757; doi:10.1038/sj.bjp.0707254
Taking the sting out of pain
Authors: Nagy I , Paule C , White J , Urban L
Published: May 2007

While the role of the brain kallikrein‐kinin system in the development of various pathological processes, such as oedema formation following brain injury or induction of central hypertonia has generated major interest, the possible role of this system in nociceptive processing has received little attention. In their present paper, Mortari et al. (2007) show that bradykinin B2 receptor activation in the brain by the bradykinin analogue, Thr6‐bradykinin, isolated from the venom of the social wasp, Polybia occidentalis potently reduces acute, noxious heat‐evoked reflex responses in naive rats. The unknown underlying mechanism of this powerful antinociceptive effect reminds us that the supraspinal antinociceptive system is still a “black box” in many aspects and awaits thorough investigation.

British Journal of Pharmacology (2007) 151, 721–722; doi:10.1038/sj.bjp.0707274
K+ channel modulation of slow wave activity in the guinea‐pig prostate
Authors: Nguyen D‐T T , Lang R J , Exintaris B
Published: May 2007

Background and purpose:

The aim of this study was to investigate the role of different K+ channel populations and the inhibitory effect of various exogenously applied K+ channel openers in the regulation of slow wave activity in the guinea‐pig prostate.

Experimental approach:

Recordings of membrane potential were made using intracellular microelectrodes.

Key results:

Tetraethylammonium (TEA 300 μM and 1 mM), iberiotoxin (150 nM) and 4‐aminopyridine (4‐AP 1 mM) increased the frequency of slow wave discharge. Apamin (1–200 nM) and glibenclamide (1 μM) had no effect on slow wave activity. Lemakalim (1 μM) and PCO‐400 (1 μM) abolished the slow waves, as did sodium nitroprusside (SNP 10 μM) and calcitonin gene‐related peptide (CGRP 100 nM). The inhibitory effect of these agents was independent of a significant change in membrane potential. In the presence of 4‐AP (1 mM), TEA (1 mM) or glibenclamide (1 μM) the inhibitory actions of SNP (10 μM) were attenuated. The inhibitory actions of CGRP (100 nM) were also reversed by glibenclamide (1 μM). In contrast, isoprenaline (1 μM) did not alter the frequency of slow wave discharge.

Conclusions and implications:

These results demonstrate that BKCa and 4‐AP‐sensitive K+ channels regulate the frequency of prostatic slow wave discharge. SNP and CGRP abolish slow waves in a hyperpolarisation‐independent manner, partially via opening of KATP channels. BKCa and 4‐AP‐sensitive K+ channels also play an important role in the SNP‐induced inhibition of slow wave activity. The lack of membrane hyperpolarisation associated with the SNP‐ and CGRP‐induced inhibition implies that the channels involved in this action are not predominantly located on the smooth muscle cells.

British Journal of Pharmacology (2007) 151, 828–836; doi:10.1038/sj.bjp.0707283
Mitochondrial Medicine: Pharmacological targeting of mitochondria in disease
Authors: Armstrong J S
Published: May 2007

Mitochondria play a central role in cell life and death and are known to be important in a wide range of diseases including the cancer, diabetes, cardiovascular disease, and the age‐related neurodegenerative diseases. The unique structural and functional characteristics of mitochondria enable the selective targeting of drugs designed to modulate the function of this organelle for therapeutic gain. This review discusses mitochondrial drug targeting strategies and a variety of novel mitochondrial drug targets including the electron transport chain, mitochondrial permeability transition, Bcl‐2 family proteins and mitochondrial DNA. Mitochondrial drug‐targeting strategies will open up avenues for manipulating mitochondrial functions and allow for selective protection or eradication of cells for therapeutic gain in a variety of diseases.

British Journal of Pharmacology (2007) 151, 1154–1165; doi:10.1038/sj.bjp.0707288
Blockade of MCH1 receptor signalling ameliorates obesity and related hepatic steatosis in ovariectomized mice
Authors: Gomori A , Ishihara A , Ito M , Matsushita H , Ito M , Mashiko S , Iwaasa H , Matsuda M , Bednarek M A , Qian S , MacNeil D J , Kanatani A
Published: May 2007

Background and purpose:

Melanin‐concentrating hormone (MCH) is a cyclic orexigenic neuropeptide predominantly expressed in the lateral hypothalamus. We investigated the roles of MCH1 receptor signalling in ovariectomy (OVX)‐induced obesity in female C57BL/6J mice, an animal model of postmenopausal obesity.

Experimental approach:

The effects of blocking signalling via the MCH1 receptor on OVX‐induced obesity was investigated by using Mch1r deficient (KO) mice and chronic treatment with a selective MCH1 receptor antagonist.

Key results:

OVX induced body weight gain and increases in the weight of visceral fat and of liver; these effects were attenuated following OVX in Mch1r KO mice. OVX‐induced triglyceride (TG) accumulation and elevated expression of lipogenic genes were significantly ameliorated in the liver of Mch1r KO mice. In agreement with these results, chronic i.c.v. infusion of a selective MCH1 receptor antagonist significantly reduced body weight gain, visceral fat and liver weights in OVX mice, and hepatic TG contents and lipogenic gene expression levels were normalized.

Conclusion and implications:

Our results indicate that MCH1 receptor signalling is involved in the development of fatty liver, as well as obesity, in OVX mice, and suggest a therapeutic potential for MCH1 receptor antagonists in the treatment of obesity and fatty liver.

British Journal of Pharmacology (2007) 151, 900–908; doi:10.1038/sj.bjp.0707292
The nematode neuropeptide, AF2 (KHEYLRF‐NH2), increases voltage‐activated calcium currents in Ascaris suum muscle
Authors: Verma S , Robertson A P , Martin R J
Published: May 2007

Background and purpose:

Resistance to all the classes of anti‐nematodal drugs like the benzimidazoles, cholinergic agonists and avermectins, has now been recorded in parasites of animals and/or humans. The development of novel anthelmintics is an urgent and imperative need. Receptors of nematode neuropeptides have been suggested to be suitable target sites for novel anthelmintic drugs.

Experimental approach:

To investigate the effect of AF2 on calcium‐currents in Ascaris suum somatic muscle cells we employed the two‐micropipette current–clamp and voltage–clamp techniques and a brief application of AF2.

Key results:

Here we report the isolation of voltage‐activated, transient, inward calcium currents. These currents are similar in characteristics to Caenorhabditis elegans UNC‐2 type currents, non‐L‐type calcium currents. Following a 2‐minute application of 1 μM AF2, there was a significant long‐lasting increase in the transient inward calcium current; AF2 increased the maximum current (from −84 nA to −158 nA) by shifting the threshold in the hyperpolarising direction (V50 changed from −7.2 to −12.8 mV) and increasing the maximum conductance change from 1.91 to 2.94 μS.

Conclusion and Implications:

These studies demonstrate a mechanism by which AF2 increased the excitability of the neuromuscular system by modulating calcium currents in nematodes. A selective small molecule agonist of the AF2 receptor is predicted to increase the contraction and act synergistically with cholinergic anthelmintics and could counter resistance to these compounds.

British Journal of Pharmacology (2007) 151, 888–899; doi:10.1038/sj.bjp.0707296
Apoptotic mimicry: phosphatidylserine liposomes reduce inflammation through activation of peroxisome proliferator‐activated receptors (PPARs) in vivo
Authors: Ramos G C , Fernandes D , Charão C T , Souza D G , Teixeira M M , Assreuy J
Published: May 2007

Background and purpose:

Recently, there has been much attention paid to understanding the molecular mechanisms underlying apoptosis and the functional consequences of apoptotic body clearance by phagocytes. In an attempt to investigate this latter aspect, the present study evaluated the anti‐inflammatory effects of in vivo administration of phosphatidylserine (PS) liposomes, a well‐characterised membrane component expressed during apoptosis. The participation of peroxisome proliferator‐activated receptors (PPARs) in PS‐mediated effects was also investigated.

Experimental approach:

The anti‐inflammatory effect of PS liposomes on the delayed phase of carrageenan mouse paw oedema was studied. PS liposomes were injected at different doses and times, after carrageenan. Hind paws were collected for evaluation of interleukin‐1β (IL‐1β) levels, myeloperoxidase (MPO) and N‐acetyl‐glucosaminidase (NAG) activities and Evans blue dye leakage. Participation of PPAR pathways was explored by using PPAR antagonists (BADGE and GW9662).

Key results:

Administration of PS, but not phosphatidylcholine (PC), liposomes (20–200 mg kg−1, i.p., 8 h after carrageenan) reduced the paw oedema in a dose‐dependent manner. PS liposomes were effective even when administered 24 and 48 h after carrageenan, a time at which indomethacin (1 mg kg−1, i.p.) had no significant effects. Carrageenan‐induced Evans blue leakage and IL‐1β production was decreased in PS‐treated paws. The PPAR antagonists (BADGE and GW9662) partially prevented the anti‐inflammatory effects of PS administration.

Conclusions and implications:

PS liposomes have anti‐inflammatory effects in vivo that are at least partly dependent on PPAR activation. Therapeutic strategies mimicking apoptosis may be useful for the treatment of inflammatory disorders.

British Journal of Pharmacology (2007) 151, 844–850; doi:10.1038/sj.bjp.0707302
Localization of intracellular compartments that exchange Na,K‐ATPase molecules with the plasma membrane in a hormone‐dependent manner
Authors: Efendiev R , Das‐Panja K , Cinelli A R , Bertorello A M , Pedemonte C H
Published: May 2007

Background and Purpose:

Dopamine is a major regulator of sodium reabsorption in proximal tubule epithelia. By binding to D1‐receptors, dopamine induces endocytosis of plasma membrane Na,K‐ATPase, resulting in a reduced capacity of the cells to transport sodium, thus contributing to natriuresis. We have previously demonstrated several aspects of the molecular mechanism by which dopamine induces Na,K‐ATPase endocytosis; however, the location of intracellular compartments containing Na,K‐ATPase molecules has not been identified.

Experimental approach:

In this study, we used different approaches to determine the localization of Na,K‐ATPase‐containing intracellular compartments. By expression of fluorescent‐tagged Na,K‐ATPase molecules in opossum kidney cells, a cell culture model of proximal tubule epithelia, we used fluorescence microscopy to determine cellular distribution of the fluorescent molecules and the effects of dopamine on this distribution. By labelling cell surface Na,K‐ATPase molecules from the cell exterior with either biotin or an epitope‐tagged antibody, we determined the localization of the tagged Na,K‐ATPase molecules after endocytosis induced by dopamine.

Key results:

In cells expressing fluorescent‐tagged Na,K‐ATPase molecules, there were intracellular compartments containing Na,K‐ATPase molecules. These compartments were in very close proximity to the plasma membrane. Upon treatment of the cells with dopamine, the fluorescence labelling of these compartments was increased. The labelling of these compartments was also observed when the endocytosis of biotin‐ or antibody‐tagged plasma membrane Na,K‐ATPase molecules was induced by dopamine.

Conclusions and Implications:

The intracellular compartments containing Na,K‐ATPase molecules are located just underneath the plasma membrane.

British Journal of Pharmacology (2007) 151, 1006–1013; doi:10.1038/sj.bjp.0707304
Ca2+–Secretion Coupling Is Impaired in Diabetic Goto Kakizaki rats
Authors: Rose Tobias , Efendic Suad , Rupnik Marjan
Published: May 2007

The Goto Kakizaki (GK) rat is a widely used animal model to study defective glucose-stimulated insulin release in type-2 diabetes (T2D). As in T2D patients, the expression of several proteins involved in Ca2+-dependent exocytosis of insulin-containing large dense-core vesicles is dysregulated in this model. So far, a defect in late steps of insulin secretion could not be demonstrated. To resolve this apparent contradiction, we studied Ca2+–secretion coupling of healthy and GK rat β cells in acute pancreatic tissue slices by assessing exocytosis with high time-resolution membrane capacitance measurements. We found that β cells of GK rats respond to glucose stimulation with a normal increase in the cytosolic Ca2+ concentration. During trains of depolarizing pulses, the secretory activity from GK rat β cells was defective in spite of upregulated cell size and doubled voltage-activated Ca2+ currents. In GK rat β cells, evoked Ca2+ entry was significantly less efficient in triggering release than in nondiabetic controls. This impairment was neither due to a decrease of functional vesicle pool sizes nor due to different kinetics of pool refilling. Strong stimulation with two successive trains of depolarizing pulses led to a prominent activity-dependent facilitation of release in GK rat β cells, whereas secretion in controls was unaffected. Broad-spectrum inhibition of PKC sensitized Ca2+-dependent exocytosis, whereas it prevented the activity-dependent facilitation in GK rat β cells. We conclude that a decrease in the sensitivity of the GK rat β-cell to depolarization-evoked Ca2+ influx is involved in defective glucose-stimulated insulin secretion. Furthermore, we discuss a role for constitutively increased activity of one or more PKC isoenzymes in diabetic rat β cells.
Global change tipping points: above- and below-ground biotic interactions in a low diversity ecosystem
Authors: Wall Diana H
Published: May 2007

Low diversity ecosystems are expected to be more vulnerable to global changes although they have received less attention than high diversity ecosystems. Addressing the present state of the Antarctic Dry Valley region by focusing on the potential global changes that may alter the coupling of above- and below-ground species and ecosystem processes is a realistic and critical need that has value beyond the Antarctic community. Presented here are suggested implications of global change on the Dry Valley terrestrial systems and how these effects might be manifested in the future.
Treatment of acquired haemophilia with recombinant activated FVII: a critical appraisal
Authors: SUMNER M. J. , GELDZILER B. D. , PEDERSEN M. , SEREMETIS S.
Published: May 2007

Summary.  Acquired haemophilia is a rare bleeding disorder usually caused by the spontaneous formation of inhibitory antibodies to coagulation FVIII. The disease occurs most commonly in the elderly, and although acquired haemophilia may be associated with a variety of underlying conditions, up to 50% of reported cases are idiopathic. Treatment options have traditionally involved human FVIII or FIX replacement therapy (if the inhibitor titre allows), porcine FVIII or the use of activated pro‐thrombin complex concentrates. Recombinant activated coagulation FVII (rFVIIa) was available on an emergency and compassionate use basis from 1988 to 1999 at sites in Europe and North America. It has been registered in Europe for use in treating acquired haemophilia since 1996 and has recently been licensed for this indication in the United States. By directly activating FX on the surface of activated platelets at the site of injury (thereby bypassing FVIII and FIX), rFVIIa can circumvent the actions of inhibitory antibodies present in acquired haemophilia patients. This paper provides an overview of experiences with rFVIIa for the treatment of acquired haemophilia from the NovoSeven® compassionate and emergency use programmes (1989–1999), the Hemophilia and Thrombosis Research Society Registry, and independent published reports from January 1999 to September 2005. rFVIIa has been reported to provide safe and effective haemostasis as a first line therapy in patients of all ages for a variety of surgical and non‐surgical bleeding situations.
Classification of temporomandibular joint sounds based upon their reduced interference distribution
Authors: WIDMALM S.E. , WILLIAMS W.J. , CHRISTIANSEN R.L. , GUNN S.M. , PARK D. K.
Published: May 2007

summary
Temporomandibular joint (TMJ) sounds were recorded in 98 orthodontic retention patients, mean age 19 ± 8–6 (s.d.) years, by interview, auscultation and electronic recording. Sounds were found by auscultation in 41% and by interview in 32% of the subjects, more often in females than in males (P ≤ 0.05). A new method for time‐frequency analysis, the reduced interference distribution (RID), was used to classify the electronic sound recordings into five subclasses, RID types 1–5, based upon location and number of their energy peaks. RID types 1–3 had a few energy peaks close in time. RID types 4–5, typical of subjects with crepitation, had multiple energy peaks occurring close in time for a period of 20–300 ms. RID type 1, found in 45% of the subjects, typical of patients with clicking, had its dominant energy peak located in a frequency range ≤600 Hz and was significantly more common in the female than in the male subjects (P≤ 0.01). RID type 2, found in 68% of the subjects, with the dominant peak in the range 600–1200 Hz, and RID type 3, found in 38% of the subjects, with the peak in the frequency range >1200 Hz, were found to have a similar gender distribution. RID type 4, found in 49% of the subjects, had the energy peaks distributed in the frequency range ≤600 Hz. RID type 5, found in 43% of the subjects, more often in females than in males (P≤ 0.05), had the peaks distributed over the whole frequency range from about 30 Hz up to about 3000 Hz. In conclusion, a more detailed classification could be made of the TMJ sounds by displaying the RIDs than by auscultation. This suggests that RID classification methods may provide a means for differentiating sounds indicating different types of pathology.
Oral conditions and aptitude to receive implants in patients with removable partial dentures: a cross‐sectional study. Part I. Oral conditions
Authors: BASSI F. , MANTECCHINI G. , CAROSSA S. , PRETI G.
Published: May 2007

summary
The relationship between a removable partial denture (RPD) and damage caused to residual oral structures is the subject of on‐going research. A group of patients wearing RPD, treated in the same way in the same department, were recalled to evaluate their oral hygiene and to compare the clinical condition of abutment teeth with that of non‐abutment teeth. The study shows that most patients were unable to maintain high standards of oral hygiene. In the group of patients with non‐optimal hygiene the clinical condition of abutment teeth was worse than that of non‐abutment teeth. In the group of patients with optimal oral hygiene the condition of abutment teeth and non‐abutment teeth was almost identical. To increase the standards of oral hygiene it is strongly advisable to recall and follow up patients on a regular basis.
Local and systemic chemotherapy in the management of periodontal disease: an opinion and review of the concept
Authors: ADDY M. , RENTON‐HARPER P.
Published: May 2007

summary
Periodontal disease appears to arise from the interaction of pathogenic bacteria with a susceptible host. The main aims of disease management have been to establish a high standard of oral hygiene and to professionally and thoroughly debride the root surface. Chemical agents could be considered for both aspects of management. Chemoprevention using supragingivally delivered agents such as chlorhexidine may be questioned for value in the pre‐treatment hygiene phase but have well‐established efficacy immediately preoperatively and during the postoperative weeks. Long‐term maintenance use of chlorhexidine is problematic due to local side effects. Antiplaque toothpastes show modest benefits to gingivitis but are not proven to prevent recurrence of periodontitis. Chemotherapy may be directed at subgingival plaque, using antimicrobials, or at the host response using anti‐inflammatory agents. Antimicrobials can be locally or systemically delivered. In most cases antimicrobial chemotherapy should be considered adjunctive to mechanical debridement. The advantages of local and systemic chemotherapy must be balanced against the disadvantages and potential side effects of agents. Antimicrobial chemotherapy offers little or no benefit to the treatment of most chronic adult periodontitis patients and should be reserved for the more rapid or refractory types of disease, and after the debridement phase. Despite the large number of studies there are insufficient comparative data to support any one local delivery system or systemic regimen as superior to another. Systemic versus local antimicrobials have not been compared to date. Host response modifying drugs such as non‐steriodal anti‐inflammatory drugs (NSAIDs) offer the potential to reduce breakdown and promote healing, including bone regeneration. However until more data are available, NSAIDs should not be used in the management of chronic periodontal diseases, there being no specific agent(s) or regimen established for use. Chemotherapy has an important place in the management of chronic periodontal diseases but routine use must be considered as an over prescription of these valuable agents.
Reduction of microleakage in class II composite resin restorations using retentive pins
Authors: LIBERMAN R. , GORFIL C. , BEN‐AMAR A.
Published: May 2007

summary
The effect on microleakage of Bondent® parapulpal pins used in class II composite resin restorations was evaluated in vitro. Bulk and incremental packing and polymerization techniques were compared, using pins anchored at the gingival cavity walls. Evaluation of microleakage was carried out following cyclic load application and an extended thermocycling procedure by the assessment of dye penetration. The results showed that the use of pins at the gingival wall of class II composite resin restorations provided significantly improved marginal sealing. This procedure should, therefore, be regarded as an effective clinical practice.
The relationship between jaw elevator muscle surface electromyogram and simulated food resistance during dynamic condition in humans
Authors: OTTENHOFF F.A.M. , VAN DER BILT A. , VAN DER GLAS H.W. , BOSMAN F. , ABBINK J.H.
Published: May 2007

summary
In six human subjects, electromyograms (EMGs) of the masseter and temporal muscles were recorded bilaterally during experiments in which the subjects made rhythmic open‐close movements. The closing phase was counteracted by a variable external force on the mandible. Variables of the force (amplitude, time integral and work) and variables of the corresponding EMG bursts (duration, peak amplitude and time integral) were computed for each open‐close cycle. Linear regression analyses were used to determine the strength of the relationship between each EMG variable and each force variable. By step‐wise multiple regression analysis the EMG variables predicting the force variables were determined. Although there was a highly significant and positive correlation (P< 0.0005), the average coefficients of linear correlation varied from 0.46 to 0.82. The strongest relationship was observed between the time integrals of the force and EMG in the interval between the onset of the burst and the onset of occlusion. It was suggested that to assess muscle force during chewing, the time integral of EMG bursts should be computed.
Biological effects of palladium and risk of using palladium in dental casting alloys
Authors: WATAHA J.C. , HANKS C.T.
Published: May 2007

summary
In dentistry, palladium is a very common component of dental casting alloys of all types, and its use has increased over the past several decades in response to the increased cost of gold. However, there have been recent controversies, particularly in Germany, over possible adverse biological effects of using palladium in dental alloys. Therefore, the purpose of this paper is to review the known biological effects of palladium and the likelihood that these effects can be caused by dental alloys which contain palladium. In an ionic form and at sufficiently high concentrations, palladium has toxic and allergic effects on biological systems. Palladium allergy almost always occurs in individuals who are sensitive to nickel. The carcinogenic potential of the palladium ion is still unclear, although there is some evidence that it is capable of acting as a mutagen. However, there are no well documented cases of adverse biological reactions to palladium in the metallic state. Furthermore, in spite of the potential adverse biological effects of palladium ions, the risk of using palladium in dental casting alloys appears to be extremely low because of the low dissolution rate of palladium ions from these alloys.
Comfortable zone of the mandible evaluated by the constant stimuli method
Authors: ABEKURA H. , TOKUYAMA H. , HAMADA T. , MORIMOTO T.
Published: May 2007

summary
For evaluation of the comfortable zone (CZ) and the most comfortable position (MCP) of the occlusal vertical relation of the mandible, the constant stimuli method with three subjective categories of judgements was applied in 10 edentulous subjects.

The evaluated CZ was stable and about 3 mm in width. The occlusal vertical dimension (OVD) of the existing dentures was found to be located within the CZ in nine of the 10 subjects.
Posterior palatal seal adaptation: influence of a high expansion stone
Authors: SYKORA O. , SUTOW E.J.
Published: May 2007

summary
In this follow‐up investigation, the ability of a new, high expansion stone to reduce acrylic resin denture base processing distortions was studied and compared with a previously reported investigation of bases processed on buff stone. Denture bases were processed by the continuous‐injection and trial‐pack techniques on flat vault palate casts and then trimmed and polished. Measurements were made at the posterior palatal border opening at 1 day and 1 week immersion in water (23°C). Results showed that denture bases processed on high expansion stone had better posterior palatal seal adaptation compared with those processed on buff stone, independent of processing techniques.