Implementation of anesthesia quality indicators in Germany : A prospective, national, multicenter quality improvement study.

BACKGROUND: In 2016 the German Society of Anesthesiology and Intensive Care Medicine (DGAI) and the Association of German Anesthetists (BDA) published 10 quality indicators (QI) to compare and improve the quality of anesthesia care in Germany. So far, there is no evidence for the feasibility of implementation of these QI in hospitals. OBJECTIVE: This study tested the hypothesis that the implementation of the 10 QI is feasible in German hospitals. MATERIAL AND METHODS: This prospective three-phase national multicenter quality improvement study was conducted in 15 German hospitals and 1 outpatient anesthesia center from March 2017 to February 2018. The trial consisted of an initial evaluation of pre-existing structures and processes by the heads of the participating anesthesia departments, followed by a 6-month implementation phase of the QI as well as a final re-evaluation phase. The implementation procedure was supported by web-based implementation aids ( www.qi-an.org ) and internal quality management programs. The primary endpoint was the difference in the number of implemented QI per center before and after implementation. Secondary endpoints were the number of newly implemented QI per center, the overall number of successful implementations of each QI, the identification of problems during the implementation as well as the kind of impediments preventing the QI implementation. RESULTS: The average number of implemented QI increased from 5.8 to 6.8 (mean of the differences 1.1 ± 1.3; P < 0.01). Most frequently the QI perioperative morbidity and mortality report (5 centers) and the QI temperature management (4 centers) could be implemented. After the implementation phase, the QI incidence management and patient blood management were implemented in all 16 centers. Implementation of other quality indicators failed mainly due to a lack of time and lack of structural resources. CONCLUSION: In this study the implementation of QI was proven to be mostly feasible in the participating German hospitals. Although several QI could be implemented with minor effort, more time, financial and structural resources would be required for some QI, such as the QI postoperative visit.

[Implementation of anesthesia quality indicators in Germany : A prospective, national, multicenter quality improvement study]. / Implementierung anästhesiologischer Qualitätsindikatoren in Deutschland : Eine prospektive, nationale, multizentrische Qualitätssteigerungsstudie German version.

BACKGROUND: In 2016 the German Society of Anesthesiology and Intensive Care Medicine (DGAI) and the Association of German Anesthetists (BDA) published 10 quality indicators (QI) to compare and improve the quality of anesthesia care in Germany. So far, there is no evidence for the feasibility of implementation of these QI in hospitals. OBJECTIVE: This study tested the hypothesis that the implementation of the 10 QI is feasible in German hospitals. MATERIAL AND METHODS: This prospective three-phase national multicenter quality improvement study was conducted in 15 German hospitals and 1 outpatient anesthesia center from March 2017 to February 2018. The trial consisted of an initial evaluation of pre-existing structures and processes by the heads of the participating anesthesia departments, followed by a 6-month implementation phase of the QI as well as a final re-evaluation phase. The implementation procedure was supported by web-based implementation aids ( www.qi-an.org ) and internal quality management programs. The primary endpoint was the difference in the number of implemented QI per center before and after implementation. Secondary endpoints were the number of newly implemented QI per center, the overall number of successful implementations of each QI, the identification of problems during the implementation as well as the kind of impediments preventing the QI implementation. RESULTS: The average number of implemented QI increased from 5.8 to 6.8 (mean of the differences 1.1 ± 1.3; P < 0.01). Most frequently the QI perioperative morbidity and mortality report (5 centers) and the QI temperature management (4 centers) could be implemented. After the implementation phase, the QI incidence management and patient blood management were implemented in all 16 centers. Implementation of other quality indicators failed mainly due to a lack of time and lack of structural resources. CONCLUSION: In this study the implementation of QI was proven to be mostly feasible in the participating German hospitals. Although several QI could be implemented with minor effort, more time, financial and structural resources would be required for some QI, such as the QI postoperative visit.

The First Samples from Almahata Sitta Showing Contacts Between Ureilitic and Chondritic Lithologies: Implications for the Structure and Composition of Asteroid 2008 TC3.

Almahata Sitta (AhS), an anomalous polymict ureilite, is the first meteorite observed to originate from a spectrally classified asteroid (2008 TC3). However, correlating properties of the meteorite with those of the asteroid is not straightforward because the AhS stones are diverse types. Of those studied prior to this work, 70-80% are ureilites (achondrites) and 20-30% are various types of chondrites. Asteroid 2008 TC3 was a heterogeneous breccia that disintegrated in the atmosphere, with its clasts landing on Earth as individual stones and most of its mass lost. We describe AhS 91A and AhS 671, which are the first AhS stones to show contacts between ureilitic and chondritic materials and provide direct information about the structure and composition of asteroid 2008 TC3. AhS 91A and AhS 671 are friable breccias, consisting of a C1 lithology that encloses rounded to angular clasts (<10 µm to 3 mm) of olivine, pyroxenes, plagioclase, graphite, and metal-sulfide, as well as chondrules (~130-600 µm) and chondrule fragments. The C1 material consists of fine-grained phyllosilicates (serpentine and saponite) and amorphous material, magnetite, breunnerite, dolomite, fayalitic olivine (Fo 28-42), an unidentified Ca-rich silicate phase, Fe,Ni sulfides, and minor Ca-phosphate and ilmenite. It has similarities to CI1 but shows evidence of heterogeneous thermal metamorphism. Its bulk oxygen isotope composition (δ18O = 13.53‰, δ17O = 8.93‰) is unlike that of any known chondrite, but similar to compositions of several CC-like clasts in typical polymict ureilites. Its Cr isotope composition is unlike that of any known meteorite. The enclosed clasts and chondrules do not belong to the C1 lithology. The olivine (Fo 75-88), pyroxenes (pigeonite of Wo ~10 and orthopyroxene of Wo ~4.6), plagioclase, graphite, and some metal-sulfide are ureilitic, based on mineral compositions, textures, and oxygen isotope compositions, and represent at least six distinct ureilitic lithologies. The chondrules are probably derived from type 3 OC and/or CC, based on mineral and oxygen isotope compositions. Some of the metal-sulfide clasts are derived from EC. AhS 91A and AhS 671 are plausible representatives of the bulk of the asteroid that was lost. Reflectance spectra of AhS 91A are dark (reflectance ~0.04-0.05) and relatively featureless in VNIR, and have an ~2.7 µm absorption band due to OH- in phyllosilicates. Spectral modeling, using mixtures of laboratory VNIR reflectance spectra of AhS stones to fit the F-type spectrum of the asteroid, suggests that 2008 TC3 consisted mainly of ureilitic and AhS 91A-like materials, with as much as 40-70% of the latter, and <10% of OC, EC and other meteorite types. The bulk density of AhS 91A (2.35 ± 0.05 g/cm3) is lower than bulk densities of other AhS stones, and closer to estimates for the asteroid (~1.7-2.2 g/cm3). Its porosity (36%) is near the low end of estimates for the asteroid (33-50%), suggesting significant macroporosity. The textures of AhS 91A and AhS 671 (finely comminuted clasts of disparate materials intimately mixed) support formation of 2008 TC3 in a regolith environment. AhS 91A and AhS 671 could represent a volume of regolith formed when a CC-like body impacted into already well-gardened ureilitic + impactor-derived debris. AhS 91A bulk samples do not show a solar wind (SW) component, so they represent sub-surface layers. AhS 91A has a lower cosmic ray exposure (CRE) age (~5-9 Ma) than previously studied AhS stones (11-22 Ma). The spread in CRE ages argues for irradiation in a regolith environment. AhS 91A and AhS 671 show that ureilitic asteroids could have detectable ~2.7 µm absorption bands.

Development and Implementation of a Novel Sulfur Removal Process from H2S Containing Wastewaters.

A novel process for removing sulfur from wastewater containing dissolved sulfide has been developed and implemented in a membrane bioreactor (MBR) process treating anaerobically pretreated industrial (pulp and paper) wastewater at the Gippsland Water Factory. Controlled oxygen addition to the first bioreactor zone (constituting 27.7% of the total bioreactor volume) to create oxygen-limiting conditions, followed by oxygen-sufficient conditions in the remaining zones of the bioreactor, provide the necessary conditions. Dissolved sulfide is oxidized to elemental sulfur in the first zone, and the accumulated sulfur is retained in the bioreactor mixed liquor suspended solids (MLSS) in the remaining zones. Accumulated sulfur is removed from the process in the waste activated sludge (WAS). Oxidation of dissolved sulfide to elemental sulfur reduces the associated process oxygen requirement by 75% compared to oxidation to sulfate. Microscopic examinations confirm that biological accumulation of elemental sulfur occurs. Process performance was analyzed during a nearly 2-year commissioning and optimization period. Addition of air in proportion to the process influent dissolved sulfide loading proved the most effective process control approach, followed by the maintenance of dissolved oxygen concentrations of 1.0 and 1.5 mg/L in the two downstream bioreactor zones. Sufficient oxygen is added for the stoichiometric conversion of dissolved sulfide to elemental sulfur. Enhanced biological phosphorus removal also occurred under these conditions, thereby simplifying supplemental phosphorus addition. These operating conditions also appear to lead to low and stable capillary suction time values for the MBR mixed liquor.

Argon reduces neurohistopathological damage and preserves functional recovery after cardiac arrest in rats.

BACKGROUND: Xenon has profound neuroprotective effects after neurological injury and is currently undergoing phase 2 clinical trials in cardiac arrest patients. However, xenon is very costly, which might preclude its widespread use. We hypothesized argon, which is more available, might also protect central nervous tissues and allow better functional recovery in a rodent model of global cerebral ischaemia. METHODS: Fourteen male Sprague-Dawley rats were subjected to 7 min of cardiac arrest and 3 min of cardiopulmonary resuscitation (CPR). One hour after successful CPR, animals were randomized to either ventilation with 70% argon in oxygen (n = 7) for 1 h or 70% nitrogen (controls, n=7). A neurological deficit score (NDS) was calculated daily for the following 7 days, then the animals were killed and the brains harvested for histopathological analyses. RESULTS: All animals survived. Control rats had severe neurological dysfunction, while argon-treated animals showed significant improvements in the NDS at all time points. This was paralleled by a significant reduction in the neuronal damage index in the neocortex and the hippocampal CA 3/4 region. CONCLUSIONS: Our study demonstrates that a single 1 h application of 70% argon significantly reduced histopathological damage of the neocortex and hippocampus, associated with a marked improvement in functional neurological recovery.

Effect of monthly ibandronate on hip structural geometry in men with low bone density.

UNLABELLED: Hip structural analysis (HSA) performed in a subset of participants from the STudy Researching Osteoporosis iN Guys (STRONG) demonstrated that 1 year of ibandronate treatment was associated with a significant improvement in some but not all parameters of hip geometry relative to placebo in men with low bone density. INTRODUCTION: HSA was performed on dual-energy X-ray absorptiometry (DXA) images in a subset of participants from the STRONG to examine the impact of monthly ibandronate on geometric properties of the hip in men with low bone density. METHODS: This prespecified subgroup analysis evaluated men in the intent-to-treat population of STRONG with baseline and 12-month DXA data. Cross-sectional geometric parameters of the femoral shaft (FS), intertrochanter region (IT), and narrow neck (NN) were calculated from femoral DXA scans. All analyses were exploratory. Treatment differences were evaluated using analysis of covariance, which adjusted for baseline parameter value, testosterone level, and treatment. RESULTS: HSA was performed on DXA scans from 89 men (34 placebo; 55 monthly ibandronate). Significant increases in average cortical thickness and cross-sectional area and decreases (i.e., improvements) in the buckling ratio were observed at the FS and IT at 12 months for ibandronate-treated men compared with placebo-treated men. No significant differences were observed between ibandronate and placebo for any NN HSA parameters. CONCLUSIONS: One year of ibandronate treatment was associated with a significant improvement in some but not all parameters of hip geometry relative to placebo in men with low bone density, suggesting that ibandronate may improve resistance to axial compressive forces and bending forces at the hip.

Organic synthesis associated with serpentinization and carbonation on early Mars.

Water-rock interactions are relevant to planetary habitability, influencing mineralogical diversity and the production of organic molecules. We examine carbonates and silicates in the martian meteorite Allan Hills 84001 (ALH 84001), using colocated nanoscale analyses, to characterize the nature of water-rock reactions on early Mars. We find complex refractory organic material associated with mineral assemblages that formed by mineral carbonation and serpentinization reactions. The organic molecules are colocated with nanophase magnetite; both formed in situ during water-rock interactions on Mars. Two potentially distinct mechanisms of abiotic organic synthesis operated on early Mars during the late Noachian period (3.9 to 4.1 billion years ago).

Performance of cardiac output measurement derived from arterial pressure waveform analysis in patients requiring high-dose vasopressor therapy.

BACKGROUND: Arterial pressure waveform analysis of cardiac output (APCO) without external calibration (FloTrac/Vigileo™) is critically dependent upon computation of vascular tone that has necessitated several refinements of the underlying software algorithms. We hypothesized that changes in vascular tone induced by high-dose vasopressor therapy affect the accuracy of APCO measurements independently of the FloTrac software version. METHODS: In this prospective observational study, we assessed the validity of uncalibrated APCO measurements compared with transpulmonary thermodilution cardiac output (TPCO) measurements in 24 patients undergoing vasopressor therapy for the treatment of cerebral vasospasm after subarachnoid haemorrhage. RESULTS: Patients received vasoactive support with [mean (sd)] 0.53 (0.46) µg kg(-1) min(-1) norepinephrine resulting in mean arterial pressure of 104 (14) mm Hg and mean systemic vascular resistance of 943 (248) dyn s(-1) cm(-5). Cardiac output (CO) data pairs (158) were obtained simultaneously by APCO and TPCO measurements. TPCO ranged from 5.2 to 14.3 litre min(-1), and APCO from 4.1 to 13.7 litre min(-1). Bias and limits of agreement were 0.9 and 2.5 litre min(-1), resulting in an overall percentage error of 29.6% for 68 data pairs analysed with the second-generation FloTrac(®) software and 27.9% for 90 data pairs analysed with the third-generation software. Precision of the reference technique was 2.6%, while APCO measurements yielded a precision of 29.5% and 27.9% for the second- and the third-generation software, respectively. For both software versions, bias (TPCO-APCO) correlated inversely with systemic vascular resistance. CONCLUSIONS: In neurosurgical patients requiring high-dose vasopressor support, precision of uncalibrated CO measurements depended on systemic vascular resistance. Introduction of the third software algorithm did not improve the insufficient precision (>20%) for APCO measurements observed with the second software version.

Comparison of early cognitive function and recovery after desflurane or sevoflurane anaesthesia in the elderly: a double-blinded randomized controlled trial.

BACKGROUND: Postoperative cognitive dysfunction (POCD) is being recognized as a complication contributing to perioperative morbidity and mortality of the elderly. We hypothesized that the use of the shorter-acting volatile anaesthetic desflurane would be associated with less incidence of POCD when compared with sevoflurane. METHODS: Approved by the local ethical committee, 80 patients (aged 65-75 yr) were enrolled in this randomized, double-blinded study. Patients were allocated to either the desflurane (n=40) or the sevoflurane (n=40) group. The primary outcome was the cognitive Test for Attentional Performance with its subtests Alertness, Divided Attention, Visual Scanning, Working Memory, and Reaction Change. In addition, Paper-Pencil Tests [Well-being Test BF-S, Recall of Digit Span (DST), Digit-Symbol-Substitution Test, Trail Making Tests A and B, and Spielberg State-Trait Anxiety Inventory] were measured. After baseline assessment 12-24 h before operation, patients were followed up 6-8 and 66-72 h after operation. Among other outcome parameters, emergence times from anaesthesia and modified Aldrete scores were recorded. RESULTS: There was no difference in the incidence of POCD. However, according to the Paper-Pencil Tests, significant improvements for the desflurane group could be detected (Well-being Test at 6-8 h, DST at 6-8 h, and Trail Making Test at 66-72 h). Emergence was significantly faster in the desflurane group for 'time to open eyes' and 'time to extubation'. CONCLUSIONS: The total incidence of POCD showed no differences between the desflurane and the sevoflurane groups. However, the tests Well-being scale, DST, and Trail Making Test, emergence times, and patients' satisfaction were in favour of desflurane.

[Current developments in xenon research. Importance for anesthesia and intensive care medicine]. / Aktuelle Entwicklungen in der Xenonforschung. Stellenwert für die Anästhesie und Intensivmedizin.

The noble gas xenon exerts favorable anesthetic properties along with remarkable hemodynamic stability in healthy patients undergoing elective surgery. It represents the nearly ideal anesthetic and provides safe and well controllable anesthesia although the exact mechanism by which xenon produces anesthesia remains to be elucidated. In addition xenon offers organ protective properties for vital organs including the brain, heart and kidneys which seem to be synergistic when used in combination with therapeutic hypothermia. As the high cost of xenon will probably preclude its wider use as a routine anesthetic, data from extensive tests in large numbers of high risk patients is needed to confirm its possible superiority in this setting.

[Comments on the 2010 guidelines on cardiopulmonary resuscitation of the European Resuscitation Council]. / Kommentar zu den Leitlinien 2010 zur kardiopulmonalen Reanimation des European Resuscitation Council.

ADULTS: Administer chest compressions (minimum 100/min, minimum 5 cm depth) at a ratio of 30:2 with ventilation (tidal volume 500-600 ml, inspiration time 1 s, F(I)O2 if possible 1.0). Avoid any interruptions in chest compressions. After every single defibrillation attempt (initially biphasic 120-200 J, monophasic 360 J, subsequently with the respective highest energy), chest compressions are initiated again immediately for 2 min independent of the ECG rhythm. Tracheal intubation is the optimal method for securing the airway during resuscitation but should be performed only by experienced airway management providers. Laryngoscopy is performed during ongoing chest compressions; interruption of chest compressions for a maximum of 10 s to pass the tube through the vocal cords. Supraglottic airway devices are alternatives to tracheal intubation. Drug administration routes for adults and children: first choice i.v., second choice intraosseous (i.o.). Vasopressors: 1 mg epinephrine every 3-5 min i.v. After the third unsuccessful defibrillation amiodarone (300 mg i.v.), repetition (150 mg) possible. Sodium bicarbonate (50 ml 8.4%) only for excessive hyperkaliemia, metabolic acidosis, or intoxication with tricyclic antidepressants. Consider aminophylline (5 mg/kgBW). Thrombolysis during spontaneous circulation only for myocardial infarction or massive pulmonary embolism; during on-going cardiopulmonary resuscitation (CPR) only when indications of massive pulmonary embolism. Active compression-decompression (ACD-CPR) and inspiratory threshold valve (ITV-CPR) are not superior to good standard CPR. CHILDREN: Most effective improvement of outcome by prevention of full cardiorespiratory arrest. Basic life support: initially five rescue breaths, followed by chest compressions (100-120/min depth about one third of chest diameter), compression-ventilation ratio 15:2. Foreign body airway obstruction with insufficient cough: alternate back blows and chest compressions (infants), or abdominal compressions (children >1 year). Treatment of potentially reversible causes: ("4 Hs and 4 Ts") hypoxia and hypovolaemia, hypokalaemia and hyperkalaemia, hypothermia, and tension pneumothorax, tamponade, toxic/therapeutic disturbances, thrombosis (coronary/pulmonary). Advanced life support: adrenaline (epinephrine) 10 µg/kgBW i.v. or i.o. every 3-5 min. Defibrillation (4 J/kgBW; monophasic or biphasic) followed by 2 min CPR, then ECG and pulse check. NEWBORNS: Initially inflate the lungs with bag-valve mask ventilation (p(AW) 20-40 cmH2O). If heart rate remains <60/min, start chest compressions (120 chest compressions/min) and ventilation with a ratio 3:1. Maintain normothermia in preterm babies by covering them with foodgrade plastic wrap or similar. POSTRESUSCITATION PHASE: Early protocol-based intensive care stabilization; initiate mild hypothermia early regardless of initial cardiac rhythm [32-34°C for 12-24 h (adults) or 24 h (children); slow rewarming (<0.5°C/h)]. Consider percutaneous coronary intervention (PCI) in patients with presumed cardiac ischemia. Prediction of CPR outcome is not possible at the scene, determine neurological outcome <72 h after cardiac arrest with somatosensory evoked potentials, biochemical tests and neurological examination. ACUTE CORONARY SYNDROME: Even if only a weak suspicion of an acute coronary syndrome is present, record a prehospital 12-lead ECG. In parallel to pain therapy, administer aspirin (160-325 mg p.o. or i.v.) and clopidogrel (75-600 mg depending on strategy); in ST-elevation myocardial infarction (STEMI) and planned PCI also prasugrel (60 mg p.o.). Antithrombins, such as heparin (60 IU/kgBW, max. 4000 IU), enoxaparin, bivalirudin or fondaparinux depending on the diagnosis (STEMI or non-STEMI-ACS) and the planned therapeutic strategy. In STEMI define reperfusion strategy depending on duration of symptoms until PCI, age and location of infarction. TRAUMA: In severe hemorrhagic shock, definitive control of bleeding is the most important goal. For successful CPR of trauma patients a minimal intravascular volume status and management of hypoxia are essential. Aggressive fluid resuscitation, hyperventilation and excessive ventilation pressure may impair outcome in patients with severe hemorrhagic shock. TRAINING: Any CPR training is better than nothing; simplification of contents and processes is the main aim.

Low-temperature synthesis of nanoscale ferromagnetic α'-MnB.

The search for tunable, size-dependent properties and unique processability has triggered the development of new synthetic routes for transition metal borides. MnB is a soft to semi-hard ferromagnetic material. This boride is now available by bottom-up, low-temperature solution chemistry. It is obtained as an unexpected metastable α'-variant that crystallises with a stacking-fault dominated CrB-type structure, as shown by transmission electron microscopy and X-ray powder diffraction (space group Cmcm, a = 300.5(8), b = 768.6(2), and c = 295.3(4) pm). The nanostructured powder consists of agglomerates of small particles (mean diameter of 85(41) nm) and transforms into well-known ß-MnB with FeB-type structure at 1523 K. The room temperature ferromagnetic behavior (TC = 545 K) is attributed to the positive exchange-correlation between the manganese atoms, that have many unpaired d electrons.

Incidence of postoperative nausea and emetic episodes after xenon anaesthesia compared with propofol-based anaesthesia.

BACKGROUND: Xenon has been proved to be safe and efficacious for general anaesthesia in numerous trials. In addition, experimental studies demonstrate that xenon inhibits the 5-hydroxytryptamine type 3 (5-HT(3)) receptor. As 5-HT(3) receptor antagonists are known to decrease postoperative nausea and vomiting (PONV) to an extent comparable with a propofol-based total i.v. technique, we tested the hypothesis that general anaesthesia with xenon would result in a reduced incidence of PONV similar to that observed with propofol-based anaesthesia. METHODS: After obtaining approval from the local ethics committee and written informed consent, 142 patients were randomized to receive xenon anaesthesia or propofol-based total i.v. anaesthesia (TIVA), both supplemented with remifentanil. The incidence of postoperative nausea and emetic episodes was recorded in the post-anaesthesia care unit and on the ward more than 24 h after anaesthesia. RESULTS: A total of 142 patients were equally distributed between the xenon and TIVA groups. Anaesthesia was maintained with mean (sd) concentrations of either xenon 61 (2)% or propofol 100 (20) microg kg(-1) min(-1). Incidences of nausea and emetic episodes over the whole 24-h period were 66.2% and 35.2% in the xenon group and 26.8% and 16.9% in the TIVA group (P<0.001 and P<0.021). CONCLUSION: Despite knowing the 5-HT(3) antagonistic properties of xenon, its use is associated with a higher incidence of nausea and emetic episodes compared with TIVA with propofol.

Positron emission tomography study of regional cerebral blood flow and flow-metabolism coupling during general anaesthesia with xenon in humans.

BACKGROUND: The effects of xenon on regional cerebral blood flow (rCBF) are controversial. Moreover, the precise sites of action at which xenon exerts its effects in the human brain remain to be established. METHODS: rCBF was sequentially assessed by H(2)(15)O positron emission tomography in six volunteers. rCBF was determined at baseline and during general anaesthesia induced with propofol and maintained with one minimum alveolar concentration xenon. rCBF measurements were started after the calculated plasma concentration of propofol had decreased to subanaesthetic levels (<1.0 microg ml(-1)). Changes in rCBF were calculated for 13 cerebral volumes of interest by measurement of a semi-quantitative perfusion index (PI). In addition, voxel-wise changes in rCBF were analysed using statistical parametric mapping. RESULTS: Xenon had only minor effects on PI in grey matter volumes of interest. In contrast, PI was increased in white matter [from 1.01 (0.11) to 1.24 (0.15) kcnt ml(-1) MBq(-1), P=0.05, mean (SD)]. Voxel-based analysis showed an increase of rCBF in white matter and a relative decrease of rCBF during xenon anaesthesia in distinct grey matter regions, particularly the orbito- and mesiofrontal cortex, cingulate gyrus, thalamus, hippocampus and bilateral cerebellum (P<0.05 corrected). When correlating PI with cerebral metabolic rate of glucose (previously obtained in another group of six volunteers using (18)F-fluorodeoxyglucose as tracer), the flow-metabolism coupling was preserved during xenon anaesthesia. CONCLUSIONS: Xenon exerted distinct regional effects on CBF: relative decreases in several cortical, subcortical, and cerebellar areas were accompanied by an increase in white matter. Flow-metabolism coupling was not impaired during xenon anaesthesia.

A comparison of waste gas concentrations during xenon or nitrous oxide anaesthesia.

BACKGROUND AND OBJECTIVE: The aim of this study was to compare waste gas concentrations during xenon or nitrous oxide anaesthesia. METHODS: A total of 64 patients were included in this study. Gas concentrations were measured with a mass spectrometer during anaesthesia. The probes were taken beside the patient's head and thorax and at a height of 180 cm above and at the floor level. RESULTS: In both groups, waste gas concentrations peak after intubation and extubation. Waste gas levels during xenon anaesthesia are low compared with nitrous oxide. CONCLUSIONS: The low waste gas levels of xenon seem to be beneficial compared to nitrous oxide.

Organic synthesis on Mars by electrochemical reduction of CO2.

The sources and nature of organic carbon on Mars have been a subject of intense research. Steele et al. (2012) showed that 10 martian meteorites contain macromolecular carbon phases contained within pyroxene- and olivine-hosted melt inclusions. Here, we show that martian meteorites Tissint, Nakhla, and NWA 1950 have an inventory of organic carbon species associated with fluid-mineral reactions that are remarkably consistent with those detected by the Mars Science Laboratory (MSL) mission. We advance the hypothesis that interactions among spinel-group minerals, sulfides, and a brine enable the electrochemical reduction of aqueous CO2 to organic molecules. Although documented here in martian samples, a similar process likely occurs wherever igneous rocks containing spinel-group minerals and/or sulfides encounter brines.

Evaluation of a wireless activity monitoring system to quantify locomotor activity in horses in experimental settings.

REASONS FOR PERFORMING STUDY: Methods of evaluating locomotor activity can be useful in efforts to quantify behavioural activity in horses objectively. OBJECTIVES: To evaluate whether an accelerometric device would be adequate to quantify locomotor activity and step frequency in horses, and to distinguish between different levels of activity and different gaits. STUDY DESIGN: Observational study in an experimental setting. METHODS: Dual-mode (activity and step count) piezo-electric accelerometric devices were placed at each of 4 locations (head, withers, forelimb and hindlimb) in each of 6 horses performing different controlled activities including grazing, walking at different speeds, trotting and cantering. Both the activity count and step count were recorded and compared by the various activities. Statistical analyses included analysis of variance for repeated measures, receiver operating characteristic curves, Bland-Altman analysis and linear regression. RESULTS: The accelerometric device was able to quantify locomotor activity at each of the 4 locations investigated and to distinguish between gaits and speeds. The activity count recorded by the accelerometer placed on the hindlimb was the most accurate, displaying a clear discrimination between the different levels of activity and a linear correlation to speed. The accelerometer placed on the head was the only one to distinguish specifically grazing behaviour from standing. The accelerometer placed on the withers was unable to differentiate different gaits and activity levels. The step count function measured at the hindlimb was reliable but the count was doubled at the walk. CONCLUSIONS: The dual-mode accelerometric device was sufficiently accurate to quantify and compare locomotor activity in horses moving at different speeds and gaits. Positioning the device on the hindlimb allowed for the most accurate results. The step count function can be useful but must be manually corrected, especially at the walk.

Raman Imaging Spectroscopy of a Putative Microfossil from the ∼3.46 Ga Apex Chert: Insights from Quartz Grain Orientation.

The utility of nondestructive laser Raman for testing the biogenicity of microfossil-like structures in ancient rocks is promising, yet results from deposits like the ∼3.46 Ga Apex chert remain contentious. The essence of the debate is that associated microstructures, which are not purported to be microfossils, also contain reduced carbon that displays Raman D- and G-band peaks similar to those seen in the purported microfossils. This has led to the hypothesis that all features including reported microfossils are due to compression of nonfossil carbon during crystal growth around quartz spherulites or more angular crystals. In this scenario, the precursor to this macromolecular carbon may or may not have been of biogenic origin, while the arcuate and linear features described would be pseudofossils. To test this hypothesis, we have undertaken 2-D micro-Raman imaging of the Eoleptonema apex holotype and associated features using instrumentation with a high spatial and spectral resolution. In addition to this, we utilized the ratio of two Raman active quartz mode intensities (I129/I461) to assess quartz grain orientation and grain-splitting artifacts. These data lead us to conclude that the holotype of Eoleptonema apex is a sheet-shaped pseudofossil that appears to be a carbon infilled intragranular crack; therefore other holotypes should be carefully reexamined for syngenicity.

Mastering hysteresis in magnetocaloric materials.

Hysteresis is more than just an interesting oddity that occurs in materials with a first-order transition. It is a real obstacle on the path from existing laboratory-scale prototypes of magnetic refrigerators towards commercialization of this potentially disruptive cooling technology. Indeed, the reversibility of the magnetocaloric effect, being essential for magnetic heat pumps, strongly depends on the width of the thermal hysteresis and, therefore, it is necessary to understand the mechanisms causing hysteresis and to find solutions to minimize losses associated with thermal hysteresis in order to maximize the efficiency of magnetic cooling devices. In this work, we discuss the fundamental aspects that can contribute to thermal hysteresis and the strategies that we are developing to at least partially overcome the hysteresis problem in some selected classes of magnetocaloric materials with large application potential. In doing so, we refer to the most relevant classes of magnetic refrigerants La-Fe-Si-, Heusler- and Fe2P-type compounds.This article is part of the themed issue 'Taking the temperature of phase transitions in cool materials'.