Abstract: The invention relates to a piston and cylinder assembly (12) of a downhole tool (10), and in particular to a piston and cylinder assembly of a rotary steerable tool. The piston (20) has an outer wall (80) which is in direct sliding contact with a wall of the cylinder (12) whereby to provide a solid sealing interface without elastomer seals. The cylinder has a retainer (22) for the piston, the retainer having at least one retaining part, the piston having at least one retained part (74), the retaining part and the retained part cooperating to retain the piston in the cylinder. The retained part is separate from the outer wall. The invention avoids the requirement for cross pins or the like to retain the piston in the cylinder and thereby avoids any holes or other discontinuities in the sealing surfaces. The invention thereby separates the function of retaining the piston from sealing the piston to cylinder interface.

Abstract: A high frequency torsional oscillation mitigation tool for use in a downhole drilling assembly. The tool has a first end, a second end, and a one-way coupling therebetween. The one-way coupling has a first part connected to rotate with the first end and a second part connected to rotate with the second end. The one-way coupling has an engaged condition in which the first part and the second part can rotate together in a first rotational direction whereby drill string rotation can be communicated to the drill bit. The one-way coupling has a disengaged condition in which the first part can rotate relative to the second part in a second rotational direction. The one-way coupling can have multiple sets of driving elements along its longitudinal axis. The tool can include a locking mechanism to override the one-way coupling for recovering a stuck downhole assembly.

Abstract: The invention relates to a downhole assembly to mitigate high frequency torsional oscillation, in particular the high frequency torsional oscillation which can occur in a drilling operation for geothermal energy or for oil and gas. The downhole assembly (10) has a rotary steerable tool (18) and a high frequency torsional oscillation mitigation tool (20), the high frequency torsional oscillation mitigation tool having a one-way coupling (100), the high frequency torsional oscillation mitigation tool being located above the rotary steerable tool. The invention also relates to an oscillation mitigation tool (20) suitable for use in a downhole assembly. The high frequency torsional oscillation mitigation tool has a first end, a second end, and a one-way coupling (100) between the first end and the second end.

Abstract: Disclosed are compounds of Formula (IVA), or a salt thereof, and pharmaceutical formulations (pharmaceutical compositions) comprising those compounds, or a salt thereof: Formula (IVA), wherein “RIa”, “RIb”, “RIc”, “RId”, “RIe”, are defined herein above, which compounds are believed suitable for use in positive modulation of the alpha 7 nicotinic acetylcholine receptor (?7 nAChR) receptors, for example, those found in the cerebral cortex and the hippocampus. Such compounds and pharmaceutical formulations are believed to be useful in treatment or management of neurodegenerative diseases, for example, Alzheimer's disease (AD), schizophrenia, and Parkinson's disease (PD), or movement disorders arising from use of certain medications used in the treatment or management of Parkinson's disease.