Elucidating the Structure and Composition of Individual Bimetallic Nanoparticles in Supported Catalysts by Atom Probe Tomography.

Understanding and controlling the structure and composition of nanoparticles in supported metal catalysts are crucial to improve chemical processes. For this, atom probe tomography (APT) is a unique tool, as it allows for spatially resolved three-dimensional chemical imaging of materials with sub-nanometer resolution. However, thus far APT has not been applied for mesoporous oxide-supported metal catalyst materials, due to the size and number of pores resulting in sample fracture during experiments.

Feasibility of Bluetooth Low Energy wearable tags to quantify healthcare worker proximity networks and patient close contact: A pilot study.

Background: The hospital environment is characterised by a dense network of interactions between healthcare workers (HCWs) and patients. As highlighted by the coronavirus pandemic, this represents a risk for disease transmission and a challenge for contact tracing. We aimed to develop and pilot an automated system to address this challenge and describe contacts between HCWs and patients.

Geomechanical simulation of energy storage in salt formations.

A promising option for storing large-scale quantities of green gases (e.g., hydrogen) is in subsurface rock salt caverns.

Surface microstructures developed on polished quartz crystals embedded in wet quartz sand compacted under hydrothermal conditions.

Intergranular pressure solution plays a key role as a deformation mechanism during diagenesis and in fault sealing and healing. Here, we present microstructural observations following experiments conducted on quartz aggregates under conditions known to favor pressure solution. We conducted two long term experiments in which a quartz crystal with polished faces of known crystallographic orientation was embedded in a matrix of randomly oriented quartz sand grains.

Seismic Slip-Pulse Experiments Simulate Induced Earthquake Rupture in the Groningen Gas Field.

Rock materials show dramatic dynamic weakening in large-displacement (m), high-velocity (∼1 m/s) friction experiments, providing a mechanism for the generation of large, natural earthquakes. However, whether such weakening occurs during induced M3-4 earthquakes (dm displacements) is unknown. We performed rotary-shear experiments on simulated fault gouges prepared from the source-, reservoir- and caprock formations present in the seismogenic Groningen gas field (Netherlands).

Microphysical Modeling of Carbonate Fault Friction at Slip Rates Spanning the Full Seismic Cycle.

Laboratory studies suggest that seismogenic rupture on faults in carbonate terrains can be explained by a transition from high friction, at low sliding velocities (), to low friction due to rapid dynamic weakening as seismic slip velocities are approached. However, consensus on the controlling physical processes is lacking. We previously proposed a microphysically based model (the "Chen-Niemeijer-Spiers" [CNS] model) that accounts for the (rate-and-state) frictional behavior of carbonate fault gouges seen at low velocities characteristic of rupture nucleation.

Nucleation of Stick-Slip Instability Within a Large-Scale Experimental Fault: Effects of Stress Heterogeneities Due to Loading and Gouge Layer Compaction.

Geodetic observations and large-scale laboratory experiments show that seismic instability is preceded by slow slip within a finite nucleation zone. In laboratory experiments rupture nucleation is studied mostly using bare (rock) interfaces, whereas upper crustal faults are typically filled with gouge. To investigate effects of gouge on rupture nucleation, we performed a biaxial shearing experiment on a 350 mm long saw-cut fault filled with gypsum gouge, at room temperature and a minimum horizontal stress  = 0.

Healing Behavior of Simulated Fault Gouges From the Groningen Gas Field and Implications for Induced Fault Reactivation.

We investigated the frictional strength recovery (healing) and subsequent reactivation and slip-weakening behavior of simulated fault gouges derived from key stratigraphic units in the seismogenic Groningen gas field (N. E. Netherlands).

Investigating Compaction by Intergranular Pressure Solution Using the Discrete Element Method.

Intergranular pressure solution creep is an important deformation mechanism in the Earth's crust. The phenomenon has been frequently studied and several analytical models have been proposed that describe its constitutive behavior. These models require assumptions regarding the geometry of the aggregate and the grain size distribution in order to solve for the contact stresses and often neglect shear tractions.

Microscale cavitation as a mechanism for nucleating earthquakes at the base of the seismogenic zone.

Major earthquakes frequently nucleate near the base of the seismogenic zone, close to the brittle-ductile transition. Fault zone rupture at greater depths is inhibited by ductile flow of rock. However, the microphysical mechanisms responsible for the transition from ductile flow to seismogenic brittle/frictional behaviour at shallower depths remain unclear.

Rock mechanics. Superplastic nanofibrous slip zones control seismogenic fault friction.

Understanding the internal mechanisms controlling fault friction is crucial for understanding seismogenic slip on active faults. Displacement in such fault zones is frequently localized on highly reflective (mirrorlike) slip surfaces, coated with thin films of nanogranular fault rock. We show that mirror-slip surfaces developed in experimentally simulated calcite faults consist of aligned nanogranular chains or fibers that are ductile at room conditions.

The heart and potassium: a banana republic.

The importance of potassium in maintaining stable cardiac function is a clinically understood phenomenon. Physiologically the importance of potassium in cardiac function is described by the large number of different kinds of potassium ions channels found in the heart compared to channels and membrane transport mechanisms for other ions such as sodium and calcium. Potassium is important in physiological homeostatic control of cardiac function, but is also of relevance to the diseased state, as potassium-related effects may stabilize or destabilize cardiac function.

Using the 12-lead ECG to diagnose acute myocardial infarction in the presence of left bundle branch block.

The 12-lead ECG is a powerful clinical tool used to risk stratify patients presenting to the emergency department with chest pain. In particular the ECG is used as the diagnostic tool to instigate reperfusion therapy in patients with acute coronary syndromes. The ECG features of acute myocardial infarction (AMI) may be masked by the presence of left bundle branch block (LBBB) and the ECG may be difficult to interpret.

Detecting failed thrombolysis in the accident and emergency department.

The primary objective in managing a patient with ST segment elevation myocardial infarction (STEMI) is to establish reperfusion in the infarct-related artery and to maintain it. Two approaches to coronary reperfusion are used in the UK - primary angioplasty and intravenous thrombolysis. Primary angioplasty is the gold standard approach to managing STEMI, but in the UK (due to financial, resource and personnel limitations) this is not the first-line treatment.

Managing thrombolysis in the accident and emergency department.

The optimal management of acute myocardial infarction (AMI) today is founded upon the 'open artery' theory and driven by the need for early reperfusion strategies. Numerous randomised controlled trials demonstrate the unequivocal benefit of thrombolytic therapy in reducing mortality and improving long-term prognosis. These benefits are most striking when the thrombolytic therapy is given early.

Misorientation distributions in hot deformed NaCl using electron backscattered diffraction.

EBSD orientation mapping has been used to derive subgrain boundary misorientation distributions in a series of hot deformed and etched NaCl samples. The main objective of this study has been to examine the influence of data processing, noise caused by angular resolution limits and step size on the subgrain misorientation distributions in hot deformed NaCl. Processing of non-indexed EBSD patterns increased the average misorientations in etched NaCl.

Crisis in industry: whose responsibility is it anyway?

Crisis counselling can be effective for many employees--not all in traditionally 'high risk' occupations--and can negate the long-term effects of trauma. Carole Spiers suggests ways of introducing effective procedures for post-trauma counselling.