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Study objectives: To assess the relevance of various efficacy end points established for thromboprophylaxis trials, we compared the results of the fondaparinux phase III program in major orthopedic surgery, using [...]

Fondaparinux, a selective inhibitor of factor Xa, is the first of a new class of antithrombotic compounds, the synthetic pentasaccharides. Its benefit-to-risk ratio in preventing venous thromboembolism after major orthopedic [...]

Following total hip joint replacement surgery, the most common fatal complication is venous thromboembolism, a condition in which a clot becomes lodged in a vein and obstructs blood flow. Many methods of prevention have been advocated. Use of low-dose standard heparin is convenient and is often used. New low-molecular-weight heparin has higher bioavailability, and in animal studies has been shown to have less effect on overall blood clotting. A study was undertaken of 136 patients undergoing elective hip replacement to determine the usefulness and safety of low-molecular-weight heparin in comparison to standard heparin. Low-molecular-weight heparin was given to 67 patients and standard heparin to 69 patients. Treatment continued for 10 days for both patient groups. Twelve days after surgery, 122 patients were studied with vein imaging. Of the 63 low-molecular-weight heparin patients to undergo this imaging, 30 percent were found to have deep vein thrombosis (clot formation in a deep vein), compared with 42 percent of patients who had received standard heparin; only four patients (two from each group) had symptoms. The incidence of pulmonary embolism was significantly higher in the standard heparin group than in the low-molecular-weight heparin group (32.3 percent versus 4.4 percent). Thrombosis occurring in the thigh was also significantly less common in the low-molecular-weight heparin group than the standard heparin group. Total blood loss and transfusion requirements were significantly lower in the low-molecular-weight heparin group than in the standard heparin group. These findings indicate that low-molecular-weight heparin is better than standard heparin in the prevention of thigh thrombosis and pulmonary embolism, and that low-molecular-weight heparin improved patient safety by reducing overall blood loss. (Consumer Summary produced by Reliance Medical Information, Inc.)

We present the electron density (ne) altitude profiles of Saturn's ionosphere at near‐equatorial latitudes from all 23 orbits of Cassini's Grand Finale. The data are collected by the Langmuir probe part of the Radio and Plasma Wave Science investigation. A high degree of variability in the electron density profiles is observed. However, organizing them by consecutive altitude ranges revealed clear differences between the southern and northern hemispheres. The neprofiles are shown to be more variable and connected to the D‐ring below 5,000 km in the southern hemisphere compared to the northern hemisphere. This observed variability is explained to be a consequence of an electrodynamic interaction with the D‐ring. Moreover, a density altitude profile is constructed for the northern hemisphere indicating the presence of three different ionospheric layers. Similar properties were observed during Cassini's final plunge, where the main ionospheric peak is crossed at ∼1,550‐km altitude. The Cassini Langmuir probe measured directly the uppermost layer of Saturn's atmosphere, the ionosphere, during its Grand Finale. The observations revealed a layered electron density altitude profile with evidence in the southern hemisphere of an electrodynamic type of interaction with the planet innermost D‐ring. Moreover, the main peak of the ionosphere is observed for the first time in the final plungearound 1,550 km. Cassini RPWS observations during the Grand Finale show an electrodynamic type of interaction between the topside ionosphere and the D‐ring in the southern hemisphereA layered electron density profile is observed, characterized by at least a diffusive and a chemical equilibrium regionThe main ionospheric peak is observed around 1,550 km in the final plunge

Measurements of electrons and ions in Saturn's ionosphere down to 1,500‐km altitudes as well as the ring crossing region above the ionosphere obtained by the Langmuir probe onboard the Cassini spacecraft are presented. Five nearly identical deep ionosphere flybys during the Grand Finale orbits and the Final plunge orbit revealed a rapid increase in the plasma densities and discrepancies between the electrons and ions densities (Neand Ni) near the closest approach. The small Ne/Niratio indicates the presence of a dusty plasma, a plasma which charge carrier is dominated by negatively charged heavy particles. Comparison of the Langmuir probe obtained density with the light ion density obtained by the Ion and Neutral Mass Spectrometer confirmed the presence of heavy ions. An unexpected positive floating potential of the probe was also observed when Ne/Ni≪ 1. This suggests that Saturn's ionosphere near the density peak is in a dusty plasma state consisting of negatively and positively charged heavy cluster ions. The electron temperature (Te) characteristics in the ionosphere are also investigated and unexpectedly high electron temperature value, up to 5000 K, has been observed below 2,500‐km altitude in a region where electron‐neutral collisions should be prominent. A well‐defined relationship between Teand Ne/Niratio was found, implying that the electron heating at low altitudes is related to the dusty plasma state of the ionosphere. Cassini Langmuir probe measurements revealed ion densities in excess of the electron densities, indicative of a dusty plasma, in Saturn's ionosphere below 2,500‐km altitude. Comparison of the Langmuir probe measurements with those of the Ion and Neutral Mass Spectrometer, sensitive to only lighter ions during this period, showed that heavy ions dominate in this region. Positive spacecraft potentials were also found, suggesting that Saturn's ionosphere contains dusty plasma of negatively and positively charged heavy ions. In situ measurements of Saturn's ionospheric plasma densities down to 1,500 km and the ring above the ionosphere is presentedCharge imbalance in the ions and electrons, evidence of the negatively charged heavy particles, has been observed below 2,500 kmObservations suggest that Saturn's ionosphere consists of a significant amount of negatively and positively charged heavy ions

Results from retrospective studies suggest that use of neuromuscular blocking agents during general anaesthesia might be linked to postoperative pulmonary complications. We therefore aimed to assess whether the use of neuromuscular blocking agents is associated with postoperative pulmonary complications.

As part of the American Society of Anesthesiology Brain Health Initiative goal of improving perioperative brain health for older patients, over 30 experts met at the fifth International Perioperative Neurotoxicity Workshop in San Francisco, CA, in May 2016, to discuss best practices for optimizing perioperative brain health in older adults (ie, >65 years of age). The objective of this workshop was to discuss and develop consensus solutions to improve patient management and outcomes and to discuss what older adults should be told (and by whom) about postoperative brain health risks. Thus, the workshop was provider and patient oriented as well as solution focused rather than etiology focused. For those areas in which we determined that there were limited evidence-based recommendations, we identified knowledge gaps and the types of scientific knowledge and investigations needed to direct future best practice. Because concerns about perioperative neurocognitive injury in pediatric patients are already being addressed by the SmartTots initiative, our workshop discussion (and thus this article) focuses specifically on perioperative cognition in older adults. The 2 main perioperative cognitive disorders that have been studied to date are postoperative delirium and cognitive dysfunction. Postoperative delirium is a syndrome of fluctuating changes in attention and level of consciousness that occurs in 20%–40% of patients >60 years of age after major surgery and inpatient hospitalization. Many older surgical patients also develop postoperative cognitive deficits that typically last for weeks to months, thus referred to as postoperative cognitive dysfunction. Because of the heterogeneity of different tools and thresholds used to assess and define these disorders at varying points in time after anesthesia and surgery, a recent article has proposed a new recommended nomenclature for these perioperative neurocognitive disorders. Our discussion about this topic was organized around 4 key issues: preprocedure consent, preoperative cognitive assessment, intraoperative management, and postoperative follow-up. These 4 issues also form the structure of this document. Multiple viewpoints were presented by participants and discussed at this in-person meeting, and the overall group consensus from these discussions was then drafted by a smaller writing group (the 6 primary authors of this article) into this manuscript. Of course, further studies have appeared since the workshop, which the writing group has incorporated where appropriate. All participants from this in-person meeting then had the opportunity to review, edit, and approve this final manuscript; 1 participant did not approve the final manuscript and asked for his/her name to be removed.

The spacecraft potential is often used to infer rapid changes in the thermal plasma density. The variations in spacecraft potential associated with large‐amplitude Langmuir and upper hybrid waves are investigated with the Magnetospheric Multiscale (MMS) mission. When large‐amplitude Langmuir and upper hybrid waves are observed, the spacecraft potential increases. The changes in spacecraft potential are shown to be due to enhanced photoelectron escape from the spacecraft when the wave electric fields reach large amplitude. The fluctuations in spacecraft potential follow the envelope function of the Langmuir and upper hybrid waves. Comparison with the high‐resolution electron moments shows that the changes in spacecraft potential associated with the waves are not due to density perturbations. Indeed, using the spacecraft potential as a density probe leads to unphysically large density fluctuations. In addition, the changes in spacecraft potential are shown to increase as density decreases: larger spacecraft potential changes are observed in the magnetosphere, than in the magnetosheath and solar wind. These results show that external electric fields can lead to unphysical results when the spacecraft potential is used as a density probe. The results suggest that fluctuations in the spacecraft potential alone cannot be used to determine whether nonlinear processes associated with Langmuir and upper hybrid waves, such as the ponderomotive force and three‐wave decay, are occurring. The electric field of Langmuir and upper hybrid waves increases the spacecraft potential due to enhanced photoelectron escapeIncreased spacecraft potentials associated with Langmuir and upper hybrid waves are not due to density depletions or ponderomotive forceThe magnitude of the changes in spacecraft potential due to Langmuir and upper hybrid waves becomes larger as density decreases

A major point of interest in cometary plasma physics has been the diamagnetic cavity, an unmagnetized region in the innermost part of the coma. Here we combine Langmuir and Mutual Impedance Probe measurements to investigate ion velocities and electron temperatures in the diamagnetic cavity of comet 67P, probed by the Rosetta spacecraft. We find ion velocities generally in the range 2–4 km/s, significantly above the expected neutral velocity ≲1 km/s, showing that the ions are (partially) decoupled from the neutrals, indicating that ion‐neutral drag was not responsible for balancing the outside magnetic pressure. Observations of clear wake effects on one of the Langmuir probes showed that the ion flow was close to radial and supersonic, at least with respect to the perpendicular temperature, inside the cavity and possibly in the surrounding region as well. We observed spacecraft potentials ≲−5V throughout the cavity, showing that a population of warm (∼5 eV) electrons was present throughout the parts of the cavity reached by Rosetta. Also, a population of cold ( ≲0.1eV) electrons was consistently observed throughout the cavity, but less consistently in the surrounding region, suggesting that while Rosetta never entered a region of collisionally coupled electrons, such a region was possibly not far away during the cavity crossings. The ion velocity exceeded the neutral velocity, showing that the ions were not strongly collisionally coupled to the neutral gasA population of warm electrons was present throughout the parts of the cavity reached by Rosetta, driving the spacecraft potential negativeA population of cold electrons was consistently observed inside the cavity and intermittently also in the surrounding region

Electric field measurements from cometary environments are very rare but can provide important information on how plasma waves help fashion the plasma environment. The long dwelling time of the Rosetta spacecraft close to comet 67P/Churyumov‐Gerasimenko promises to improve this state. We here present the first electric field measurements from 67P, performed by the Rosetta dual Langmuir probe instrument LAP. Measurements of the electric field from cometocentric distances of 149 and 348 km are presented together with estimates of plasma density changes. Persistent wave activity around the local H2O+lower hybrid frequency is observed, with the largest amplitudes observed at sharp plasma gradients. We demonstrate that the necessary requirements for the lower hybrid drift instability to be operating are fulfilled. We suggest that lower hybrid waves are responsible for the creation of a warm electron population, the origins of which have been unknown so far, by heating ambient electrons in the magnetic field‐parallel direction. We present first electric field measurements from the inner coma of comet 67P Churyumov‐GerasimenkoPersistent wave activity at lower hybrid frequency is collocated with plasma density gradientsThe waves can heat both electrons and ions and may explain hot plasma populations

The European Space Agency's three Swarm satellites were launched on 22 November 2013 into nearly polar, circular orbits, eventually reaching altitudes of 460 km (Swarm A and C) and 510 km (Swarm B). Swarm's multiyear mission is to make precision, multipoint measurements of low‐frequency magnetic and electric fields in Earth's ionosphere for the purpose of characterizing magnetic fields generated both inside and external to the Earth, along with the electric fields and other plasma parameters associated with electric current systems in the ionosphere and magnetosphere. Electric fields perpendicular to the magnetic field B→are determined through ion drift velocity v→iand magnetic field measurements via the relation E→⊥=−v→i×B→. Ion drift is derived from two‐dimensional images of low‐energy ion distribution functions provided by two Thermal Ion Imager (TII) sensors viewing in the horizontal and vertical planes; v→iis corrected for spacecraft potential as determined by two Langmuir probes (LPs) which also measure plasma density neand electron temperature Te. The TII sensors use a microchannel‐plate‐intensified phosphor screen imaged by a charge‐coupled device to generate high‐resolution distribution images (66 × 40 pixels) at a rate of 16 s−1. Images are partially processed on board and further on the ground to generate calibrated data products at a rate of 2 s−1; these include v→i, E→⊥, and ion temperature Tiin addition to electron temperature Teand plasma density nefrom the LPs. Swarm TII sensors provide ion velocity and temperature from core ion distribution function imagesCCD‐based imaging detectors in the TIIs support event rates that are much higher than possible with charge amplifier‐based systemsSwarm LPs use a harmonic‐mode technique to obtain electron density, temperature, and spacecraft potential at high rates

Mars Express and Mars Atmosphere and Volatile Evolution (MAVEN) observations have demonstrated the influence of Mars's spatially variable crustal magnetic fields upon the configuration of the plasma in the ionosphere. This influence furthermore leads to variations in ionospheric escape, conceivably in part through the modification of the plasma density and electron temperature in the upper ionosphere. In this study, we examine MAVEN Langmuir Probe and Waves data, finding a clear correspondence between the structure of the crustal fields and both the measured electron temperatures and densities, by first constructing an “average” profile from which departures can be quantified. Electron temperatures are shown to be lower in regions of strong crustal fields over a wide altitude range. We extend previous analyses to cover the nightside ionosphere, finding the same effects present to a lesser degree, in contrast to previous studies where the opposite relationship was found between densities and crustal fields. We further determine the altitude range over which this coupling between both plasma density (and temperature) and crustal fields is effective and use measurements made by MAVEN in the solar wind to explore the dependence of this crustal field control on the coupling to the solar wind and the interplanetary magnetic field (IMF). Based on this, there is some suggestion that variations in the solar wind dynamic pressure are associated with modulation of the effects of the crustal fields on plasma density, whereas the strength of the IMF modulates the crustal fields effects on both electron densities and temperatures. Mars's atmosphere is exposed to ultra‐violet light from the Sun, forming a layer of plasma at high altitudes around the planet. This plasma layer, termed the ionosphere, is strongly affected in terms of its density and temperature, both by external factors like the solar wind and the interplanetary magnetic field (IMF), and internal factors, like Mars's crustal magnetic field. Here, we study how effective the crustal magnetic fields are at shaping the ionosphere in both density and temperature, by first determining the average structure of the ionosphere, and then examining departures from this average. We find that plasma densities are elevated and temperatures reduced in regions where the crustal field is stronger. We also find the same effect on the nightside. This result is in apparent opposition to previous related studies, now based on a much larger data set, which we suggest may be the result of poor seasonal sampling in earlier studies. We further investigate how this crustal field control varies with the solar wind and IMF, and see evidence for weak modulation according to both the dynamic pressure exerted by the solar wind, and the strength of the IMF. We present a statistical analysis of Mars Atmosphere and Volatile Evolution Langmuir Probe and Wave densities and temperatures at MarsDensities are elevated and temperatures reduced in strong crustal field regions, on both the dayside and nightsideVariations in the driving solar wind conditions are able to affect these correlations to a modest degree We present a statistical analysis of Mars Atmosphere and Volatile Evolution Langmuir Probe and Wave densities and temperatures at Mars Densities are elevated and temperatures reduced in strong crustal field regions, on both the dayside and nightside Variations in the driving solar wind conditions are able to affect these correlations to a modest degree

Interfaces of dye-sensitized TiO2nanoparticles with electrolytes or hole conductors have been widely applied in photoelectrochemical cells. However, the fundamental understanding of their properties and function is still poor. Herein, we demonstrate that the spectral changes that occur in the visible spectrum of dye-sensitized TiO2films upon (a) Li+titration, (b) potentiostatic electron accumulation in mesoporous TiO2, and (c) photoinduced electron injection into TiO2can be explained by the Stark effect, which can then be used to characterize the change in the local electric field at the TiO2/dye/electrolyte interface. A quantitative analysis of the Stark effect indicates that the compact (Helmholtz) layer capacitance at the TiO2/dye/electrolyte interface strongly affects the strength of the local electric field. Systematic studies show that the Helmholtz layer capacitance depends strongly on the Li+concentration and surface dye coverage but is independent of the concentrations of other electrolytic species and the light intensity. These results illustrate the potential of Stark spectroscopy for the in situ study of the TiO2/dye/electrolyte interfaces and provide substantial new insights into these widely applied interfaces related to photoelectrochemistry and other research fields.

The effects of coadsorbing the amphiphilic ruthenium-based dye Z907 (cis-bis(isothiocyanato)(2,20-bipyridyl-4,40-dicarboxylato)(4,40-dinonyl-20-bipyridyl)ruthenium(II)) with the coadsorbent DPA (n-decylphosphonic acid) and with the organic dye D35 ((E)-3-(5-(4-(bis(2′,4′-dibutoxybiphenyl-4-yl)amino)phenyl)thiophen-2-yl)-2-cyanoacrylic acid) on mesoporous TiO2were investigated using photoelectron spectroscopy (PES). Z907 is expected to adsorb to the TiO2surface via the carboxylic acid groups. However, Z907 also shows signs of interacting with the TiO2via the sulfur of the thiocyanate groups, and this interaction is affected by both the addition of DPA and D35. DPA, when added, exchanges with Z907 at the TiO2surface, and each Z907 is replaced by six DPA molecules, but it does not affect the energy level alignment between Z907 and TiO2substantially. Adding D35 to Z907 induces changes in the adsorption configuration of Z907 by the means of suppressing the interaction of the thiocyanate ligands and the TiO2surface. The HOMO level of Z907 is shifted by the addition of D35. Coadsorbing Z907 with D35 thus gives changes at a molecular level, meaning that this is an example of collaborative sensitization.

Observations of the coma near the nucleus of comet 67P/Churyumov-Gerasimenko (67P) made by the IES (Ion and Electron Sensor) instrument onboard the Rosetta Orbiter during late 2014 showed that electron fluxes greatly exceeded solar wind electron fluxes. The IES is part of the Rosetta Plasma Consortium. This paper reports on electron energy spectra measured by IES near the nucleus as well as approximate densities and average energies for the suprathermal electrons when the comet was at a heliocentric distance of about 3?AU. Comparisons are made with electron densities measured by other instruments. The high electron densities observed (e.g., ne?˜?10–100?cm-3) must be associated with the cometary ion density enhancement created mainly by the photoionization of cometary gas by solar radiation; there are other processes that also contribute. Quasineutrality requires that the electron and ion densities be the same, and under certain conditions an ambipolar electric field is required to achieve quasi-neutrality. We present the results of a test particle model of cometary ion pickup by the solar wind and a two-stream electron transport code and use these results to interpret the IES data. We also estimate the effects on the electron spectrum of a compression of the electron fluid parcel. The electrons detected by IES can have energies as high as about 100–200?eV near the comet on some occasions, in which case the hot electrons can significantly enhance ionization rates of neutrals via impact ionization. Plasma environment around comet 67P at 3?AURosetta spacecraft electron density measurements in the coma and solar windRelation between hot and cold electron populations at different distances to the nucleus

Recent results from the MAVEN Langmuir Probe and Waves instrument suggest higher than predicted electron temperatures (Te) in Mars' dayside ionosphere above ~180 km in altitude. Correspondingly, measurements from Neutral Gas and Ion Mass Spectrometer indicate significant abundances of O2+up to ~500 km in altitude, suggesting that O2+may be a principal ion loss mechanism of oxygen. In this article, we investigate the effects of the higher Te(which results from electron heating) and ion heating on ion outflow and loss. Numerical solutions show that plasma processes including ion heating and higher Temay greatly increase O2+loss at Mars. In particular, enhanced Tein Mars' ionosphere just above the exobase creates a substantial ambipolar electric field with a potential (eΦ) of several kBTe, which draws ions out of the region allowing for enhanced escape. With active solar wind, electron, and ion heating, direct O2+loss could match or exceed loss via dissociative recombination of O2+. These results suggest that direct loss of O2+may have played a significant role in the loss of oxygen at Mars over time. O2+outflow at Mars is greatly enhanced by ambipolar electric fieldEnhanced electron temperatures result in a strong ambipolar electric fieldIn the past, direct loss of O2+could have exceeded that of associative recombination

The first in situ nightside electron density and temperature profiles at Mars are presented as functions of altitude and local time (LT) from the Langmuir Probe and Waves (LPW) instrument on board the Mars Atmosphere and Volatile EvolutioN (MAVEN) mission spacecraft. LPW is able to measure densities as low as ∼100  cm−3, a factor of up to 10 or greater improvement over previous measurements. Above 200 km, near‐vertical density profiles of a few hundred cubic centimeters were observed for almost all nightside LT, with the lowest densities and highest temperatures observed postmidnight. Density peaks of a few thousand cubic centimeters were observed below 200 km at all nightside LT. The lowest temperatures were observed below 180 km and approach the neutral atmospheric temperature. One‐dimensional modeling demonstrates that precipitating electrons were able to sustain the observed nightside ionospheric densities below 200 km. First in situ nightside electron density and temperature profiles on the nightside of MarsElectron temperatures approach neutral atmospheric temperatures below  200 kmElectron densities below 200 km require additional ionization source

We present Mars' electron temperature (Te) and density (ne) altitude profiles derived from the MAVEN (Mars Atmosphere and Volatile EvolutioN) mission deep dip orbits in April 2015, as measured by the Langmuir probe instrument. These orbits had periapsides below 130 km in altitude at low solar zenith angles. The periapsides were above the peak in neduring this period. Using a Chapman function fit, we find that scale height and projected altitude of the nepeak are consistent with models and previous measurements. The peak electron density is slightly higher than earlier works. For the first time, we present in situ measurements of Tealtitude profiles in Mars' dayside in the altitude range from ~130 km to 500 km and provide a functional fit. Importantly, Terises rapidly with altitude from ~180 km to ~300 km. These results and functional fit are important for modeling Mars' ionosphere and understanding atmospheric escape. First in situ measurements of the electron temperature at MarsElectron density and temperature profiles at Mars

We report on initial observations made by the Langmuir Probe and Waves relaxation soundingexperiment on board the NASA Mars Atmosphere and Volatile EvolutioN (MAVEN) mission. These measurements yield the ionospheric thermal plasma density, and we use these data here for an initial survey of its variability. Studying orbit‐to‐orbit variations, we show that the relative variability of the ionospheric plasma density is lowest at low altitudes near the photochemical peak, steadily increases toward higher altitudes and sharply increases as the spacecraft crosses the terminator and moves into the nightside. Finally, despite the small volume of data currently available, we show that a clear signature of the influence of crustal magnetic fields on the thermal plasma density fluctuations is visible. Such results are consistent with previously reported remote measurements made at higher altitudes, but crucially, here we sample a new span of altitudes between ∼130 and ∼300 km using in situ techniques. Data from the Langmuir Probe and Waves instrument reveal density structures in the Mars ionosphereMAVEN samples an altitude range which previously has only been sparsely explored in situMAVEN/LPW data also reveal the stabilizing influence of intense crustal fields

We use measurements from the Rosetta plasma consortium Langmuir probe and mutual impedance probe to study the spatial distribution of low‐energy plasma in the near‐nucleus coma of comet 67P/Churyumov‐Gerasimenko. The spatial distribution is highly structured with the highest density in the summer hemisphere and above the region connecting the two main lobes of the comet, i.e., the neck region. There is a clear correlation with the neutral density and the plasma to neutral density ratio is found to be ∼1–2·10−6, at a cometocentric distance of 10 km and at 3.1 AU from the Sun. A clear 6.2 h modulation of the plasma is seen as the neck is exposed twice per rotation. The electron density of the collisionless plasma within 260 km from the nucleus falls off with radial distance as ∼1/r. The spatial structure indicates that local ionization of neutral gas is the dominant source of low‐energy plasma around the comet. The spatial distribution of plasma around comet 67P is highly structuredLocal ionization of neutral gas dominates the plasma environmentPlasma falls off with cometocentric distance as 1/r

We present observations from the Mars Advanced Radar for Subsurface and Ionospheric Sounding (MARSIS) instrument onboard Mars Express of the thermal electron plasma density of the Martian ionosphere and investigate the extent to which it is influenced by the presence of Mars's remnant crustal magnetic fields. We use locally measured electron densities, derived when MARSIS is operating in active ionospheric sounding (AIS) mode, covering an altitude range from ∼300 km to ∼1200 km. We compare these measured densities to an empirical model of the dayside ionospheric plasma density in this diffusive transport‐dominated regime. We show that small spatial‐scale departures from the averaged values are strongly correlated with the pattern of the crustal fields. Persistently elevated densities are seen in regions of relatively stronger crustal fields across the whole altitude range. Comparing these results with measurements of the (scalar) magnetic field also obtained by MARSIS/AIS, we characterize the dayside strength of the draped magnetic fields in the same regions. Finally, we provide a revised empirical model of the plasma density in the Martian ionosphere, including parameterizations for both the crustal field‐dominated and draping‐dominated regimes. Local plasma densities and magnetic fields are measured by MARSIS onboard MEXCrustal magnetic fields influence the configuration of the ionosphereDensities are elevated over regions where the crustal field dominates

Neogene regional mafic dykes extending north of the Álftafjörður central volcano in east Iceland are studied to test models of dyke swarm emplacement at spreading ridges. This is accomplished by using anisotropy of magnetic susceptibility to define fossilized magma flow regimes. The imbrication of the foliation plane, defined by the minor susceptibility axis, is used as an indicator of the flow direction. Contemporaneous shear resolved on the dyke walls may modify a pure flow-induced fabric and such shear regimes are therefore retracted. The magma flow and palaeo-stress resolved on the dykes are determined in 13 of 24 dykes. The magma flow is interpreted as subhorizontal and northwards directed away from the central volcano for nine dykes, and found to be vertical in three cases. The preferentially subhorizontal magma flow in the Álftafjörður swarm suggests that dyke propagation in this type of Icelandic volcanic system originates in shallow crustal magma chambers. The regional tectonic palaeo-stress field is deduced to cause oblique spreading across the Álftafjörður dyke swarm and govern a subhorizontal dextral shear component on the dyke planes during propagation. This interpretation is not in conflict with the left-stepping en echelon trend distribution of individual dykes relative to the trend of the swarm.

On 6–8 June 2015, the Ion and Electron Sensor on board Rosetta observed keV‐range water‐group pickup ions arriving from the solar direction. Based on magnetic field intensification and variations, the appearance of the ions was likely to have been caused by a coronal mass ejection. During the 3‐day period when Rosetta was 200 km from the comet, peak ion energy/charge (E/q) varied over a range from 50 eV to 1 keV in concert with neutral gas density variations caused by the rotation of the comet and its variable solar illumination. Thermal ion densities showed the same variations. The neutral density variations provided a unique opportunity to observe the repeated slowing of the solar wind by mass loading caused by charge exchange between energetic water‐group ions and thermal water‐group molecules. Such solar wind slowing was observed previously only by flyby missions that provided single events. The Rosetta orbiter carried a number of instruments to measure the properties of the neutral and ionized gas surrounding the nucleus. Included in these were plasma instruments to measure the characteristics of the charged particles. The Ion and Electron Sensor was one of them. Also on board were the Rosetta Orbiter Spectrometer for Ion and Neutral Analysis, the Ion Composition Analyzer, and the Langmuir Probe. This paper discusses some of the results of measurements by these instruments and their relation to each other. It was found that the neutral gas emitted by the comet nucleus and the resulting positively charged ions interact in such a way to produce slowing down of the solar wind as a result of what is called “charge exchange”, in which an electron is transferred from a neutral molecule to an ion. Charge exchange of energetic water group pickup ions with coma water molecules is observed within the solar wind cavity of Comet 67P Churyumov‐GerasimenkoRotation of the comet produced variations in the neutral density at the spacecraft causing strong charge‐exchange deceleration of the incoming ions within the density peaksRecovery to the initial water‐group ion beam as minimum neutral densities, again appeared, was shown to result from pickup of thermal ions in the coma Charge exchange of energetic water group pickup ions with coma water molecules is observed within the solar wind cavity of Comet 67P Churyumov‐Gerasimenko Rotation of the comet produced variations in the neutral density at the spacecraft causing strong charge‐exchange deceleration of the incoming ions within the density peaks Recovery to the initial water‐group ion beam as minimum neutral densities, again appeared, was shown to result from pickup of thermal ions in the coma

Post-operative complications after total hip or knee replacement can delay recovery, prolong hospitalisation, increase rates of re-admission and, in the most severe cases, lead to long-term disability or even death. In this analysis of pooled data from four large, randomised, phase III clinical trials that compared the oral, direct Factor Xa inhibitor rivaroxaban with subcutaneous enoxaparin for the prevention of venous thromboembolism after total hip or knee replacement (n = 12 729), the incidence of complications, including bleeding and adverse events related to surgery (such as wound infection, wound dehiscence and haemarthrosis) are reported. Interventions and procedures relating to surgery are also compared between the groups. Bleeding events, including excessive wound haematoma and surgical-site bleeding, occurred at similar rates in the rivaroxaban and enoxaparin groups. Over the total study duration, adverse surgical events occurred at a similar rate in the rivaroxaban group compared with the enoxaparin group after total knee replacement (2.26% vs 2.69%, respectively) and total hip replacement (1.48% vs1.65%, respectively). Blood loss, wound drainage and transfusion requirements were also similar between the two groups.This analysis shows that the incidence of adverse surgical events with rivaroxaban was similar to enoxaparin.

Learning and memory are cognitive functions commonly impaired after surgery, especially in elderly patients. Our aim was to evaluate the effect of sevoflurane anaesthesia on episodic-like memory in young and aged wild-type mice and mice with altered nicotinic cholinergic neurotransmission (2KO). Mice learned objects before randomization to control, anaesthesia or sham groups. Anaesthesia was maintained at 2.6 sevoflurane for 2 h, starting immediately after training. Object memory testing was performed after 24 h, when one familiar object was replaced by a nonfamiliar object. While nonanaesthetized mice showed memory retention of the familiar object, anaesthetized wild-type and 2KO mice showed impaired memory. Sevoflurane anaesthesia thus causes memory impairment in mice regardless of 2 receptor-mediated nicotinic cholinergic neurotransmission.

A once-daily dose of rivaroxaban 10 mg, an oral, direct Factor Xa inhibitor, was compared with enoxaparin 40 mg subcutaneously once daily for prevention of venous thromboembolism in three studies of patients undergoing elective hip and knee replacement (RECORD programme).A pooled analysis of data from these studies (n = 9581) showed that rivaroxaban was more effective than enoxaparin in reducing the incidence of the composite of symptomatic venous thromboembolism and all-cause mortality at two weeks (0.4% vs 0.8%, respectively, odds ratio 0.44; 95% confidence interval 0.23 to 0.79; p = 0.005), and at the end of the planned medication period (0.5% vs 1.3%, respectively; odds ratio 0.38; 95% confidence interval 0.22 to 0.62; p < 0.001). The rate of major bleeding was similar at two weeks (0.2% for both) and at the end of the planned medication period (0.3% vs 0.2%).Rivaroxaban started six to eight hours after surgery was more effective than enoxaparin started the previous evening in preventing symptomatic venous thromboembolism and all-cause mortality, without increasing major bleeding.

The effect of neuromuscular block on the anaesthetic depth of hypnosis is an elusive question. We simultaneously investigated the influence of neuromuscular block on the bispectral index, a measure of hypnosis during general anaesthesia, and on the electroencephalogram. Patients were anaesthetized with sevoflurane. Noxious tetanic electrical stimulation was applied on two occasions before and after profound neuromuscular block achieved with rocuronium. Neuromuscular block significantly attenuated the effect from noxious stimulation on electroencephalogram power and synchrony in the band (P<0.05), and the corresponding effect on bispectral index (P<0.02). These findings are probably due to the reduced arousing afferent input from paralysed muscles, and not to changes in the frontal electromyogram.

Heparin-induced thrombocytopenia (HIT) is caused by platelet-activating IgG antibodies that recognize platelet factor 4 (PF4) bound to heparin. Immunogenicity of heparins differs in that unfractionated heparin (UFH) induces more anti–PF4/heparin antibodies than low-molecular-weight heparin (LMWH) and UFH also causes more HIT. Fondaparinux, a synthetic anticoagulant modeled after the antithrombin-binding pentasaccharide, is believed to be nonimmunogenic. We tested 2726 patients for anti–PF4/heparin antibodies after they were randomized to receive antithrombotic prophylaxis with fondaparinux or LMWH (enoxaparin) following hip or knee surgery. We also evaluated in vitro cross-reactivity of the IgG antibodies generated against PF4 in the presence of UFH, LMWH, danaparoid, or fondaparinux. We found that anti–PF4/heparin antibodies were generated at similar frequencies in patients treated with fondaparinux or enoxaparin. Although antibodies reacted equally well in vitro against PF4/UFH and PF4/LMWH, and sometimes weakly against PF4/danaparoid, none reacted against PF4/fondaparinux, including even those sera obtained from patients who formed antibodies during fondaparinux treatment. At high concentrations, however, fondaparinux inhibited binding of HIT antibodies to PF4/polysaccharide, indicating that PF4/fondaparinux interactions occur. No patient developed HIT. We conclude that despite similar immunogenicity of fondaparinux and LMWH, PF4/fondaparinux, but not PF4/LMWH, is recognized poorly by the antibodies generated, suggesting that the risk of HIT with fondaparinux likely is very low.

Dabigatran etexilate is an oral low‐molecular‐weight direct thrombin inhibitor. Following oral administration, dabigatran etexilate is rapidly converted to its active form, dabigatran. The authors investigated the absorption, distribution, and elimination of a single 150‐mg dose capsule formulation of dabigatran etexilate in healthy volunteers and patients undergoing total hip replacement. In an open‐label, 3‐way crossover study, dabigatran etexilate was administered to 18 male volunteers in the fasted state, after administration of food and with coadministration of the proton pump inhibitor, pantoprazole. In a subsequent multicenter, open‐label study, 59 patients received a single dose of dabigatran etexilate, administered 1 to 3 hours following total hip replacement. In healthy volunteers, food had no effect on the extent of absorption of dabigatran etexilate, although there was reduced interindividual variability for dabigatran maximum plasma concentration and AUC0‐∞. A decrease in the mean dabigatran AUC0‐∞(904 to 705 ng•h/mL) occurred with coadministration of pantoprazole. In patients undergoing total hip replacement, immediate onset of absorption was seen with the maximum plasma concentration of dabigatran occurring after 6 hours. The AUC0–24of dabigatran was 88% of the steady‐state AUC using a preliminary tablet formulation and 106% of that seen in the healthy volunteer study. Compared with healthy volunteers, the postoperative profile was flattened with delayed peak concentrations. In summary, administration of the dabigatran etexilate capsule with food has no effect on the extent of dabigatran absorption, with a moderate decrease when coadministered with pantoprazole. Adequate plasma concentrations of dabigatran were seen with early postoperative administration of the dabigatran etexilate capsule. These pharmacokinetic characteristics confirm the suitability of this oral solid dosage form for use in future clinical trials.

Fondaparinux (Arixtra, Sanofi-Synthelabo, Paris, France) is a pentasaccharide that selectively inhibits factor Xa; it is the first of a new class of synthetic antithrombotic agents. Fondaparinux has a linear pharmacokinetic profile allowing once-daily subcutaneous administration. Absence of metabolism, complete bioavailability, and lack of nonspecific binding in plasma contribute to the predictability of its effect. Fondaparinux has been approved for use in the prophylaxis of venous thromboembolism following orthopedic surgery. In this setting, it was found to reduce VTE risk by more than 50 in comparison with the low molecular weight heparin enoxaparin, with an incidence of clinically important bleeding not significantly different from that of standard low molecular weight heparin regimens. Furthermore, 4 weeks of prophylaxis with fondaparinux after hip fracture surgery was shown to reduce the risk of venous thromboembolism by 96 compared with 1-week prophylaxis. Finally, the efficacy and safety of fondaparinux in the treatment of venous thromboembolism and acute coronary syndromes appears promising.

Venous thromboembolism (VTE) is a life-threatening complication following orthopedic surgery. Selective factor Xa inhibition is a new antithrombotic approach designed to avoid difficulties associated with heparins and other current anticoagulants. Several antifactor Xa compounds are in early investigation, but fondaparinux (Arixtra; NV Organon, Oss, The Netherlands; Sanofi-Synthelabo, Paris, France) is the first and most advanced compound in the development of a new class of synthetic antithrombotic agents—the selective factor Xa inhibitors. Fondaparinux has a highly favorable pharmacokinetic profile; four large phase 3 trials comparing subcutaneous fondaparinux 2.5 mg once daily with the low molecular weight heparin (LMWH) enoxaparin in doses approved by regulatory bodies showed that fondaparinux reduced the overall risk of VTE in major orthopedic surgery by > 50 without increasing clinically relevant bleeding. Fondaparinux also appears to be a very promising candidate for the treatment of patients with existing VTE.