5,806 research outputs found
Incompatible sets of gradients and metastability
We give a mathematical analysis of a concept of metastability induced by
incompatibility. The physical setting is a single parent phase, just about to
undergo transformation to a product phase of lower energy density. Under
certain conditions of incompatibility of the energy wells of this energy
density, we show that the parent phase is metastable in a strong sense, namely
it is a local minimizer of the free energy in an neighbourhood of its
deformation. The reason behind this result is that, due to the incompatibility
of the energy wells, a small nucleus of the product phase is necessarily
accompanied by a stressed transition layer whose energetic cost exceeds the
energy lowering capacity of the nucleus. We define and characterize
incompatible sets of matrices, in terms of which the transition layer estimate
at the heart of the proof of metastability is expressed. Finally we discuss
connections with experiment and place this concept of metastability in the
wider context of recent theoretical and experimental research on metastability
and hysteresis.Comment: Archive for Rational Mechanics and Analysis, to appea
Peripheral neuropathy secondary to a ‘domino’ liver transplant: a case report
Background:
Peripheral neuropathy caused by amyloidosis is one of the well-recognised sequelae of mutations in the transthyretin gene (TTR).//
Case presentation:
We describe a case of peripheral neuropathy in a White British 74 year old man with wild-type TTR, 8 years following receipt of a ‘domino’ liver transplant (from a donor with a TTR mutation). The clinical phenotype and neurophysiology, coupled with presence of ATTR amyloid deposits on fat biopsy, established the diagnosis of ATTR amyloid neuropathy, as a consequence of receipt of a variant-TTR secreting liver. A nerve biopsy was not clinically appropriate for this patient. Such cases are rare since recipients of such livers are typically restricted to people whose natural lifespan is unlikely to stretch into the anticipated symptomatic period of ATTR amyloidosis. However, novel “gene silencing” therapeutics are now available which can dramatically alter the course of this disorder, by reducing the proportion of abnormal proteins.//
Conclusions:
This represents a rare but predictable iatrogenic side effect, and doctors should be aware of this eventuality occurring in a shorter time span than previously anticipated
An Unusual Case of Serotonin Syndrome with Oxycodone and Citalopram
A 77-year-old female with recurrent non-small-cell lung cancer presented to a hospital outpatient clinic with tremor, weakness, inability to coordinate motor movements, and confusion. It was suspected that the symptoms were due to possible central nervous system metastases; however, a CT scan of her head was unremarkable. The lung clinic liaison pharmacist took a medication history from the patient, complimented by extra information from the patient's community pharmacy. The pharmacist suspected the rare side effect of serotonin syndrome was responsible for the patient's presenting symptoms caused by the combination of oxycodone and citalopram. The patient's symptoms resolved soon after oxycodone was changed to morphine
Peripheral neuropathy secondary to a ‘domino’ liver transplant:a case report
Abstract Background Peripheral neuropathy caused by amyloidosis is one of the well-recognised sequelae of mutations in the transthyretin gene (TTR). Case presentation We describe a case of peripheral neuropathy in a White British 74 year old man with wild-type TTR, 8 years following receipt of a ‘domino’ liver transplant (from a donor with a TTR mutation). The clinical phenotype and neurophysiology, coupled with presence of ATTR amyloid deposits on fat biopsy, established the diagnosis of ATTR amyloid neuropathy, as a consequence of receipt of a variant-TTR secreting liver. A nerve biopsy was not clinically appropriate for this patient. Such cases are rare since recipients of such livers are typically restricted to people whose natural lifespan is unlikely to stretch into the anticipated symptomatic period of ATTR amyloidosis. However, novel “gene silencing” therapeutics are now available which can dramatically alter the course of this disorder, by reducing the proportion of abnormal proteins. Conclusions This represents a rare but predictable iatrogenic side effect, and doctors should be aware of this eventuality occurring in a shorter time span than previously anticipated
Determination of the stretch tensor for structural transformations
The transformation stretch tensor plays an essential role in the evaluation
of conditions of compatibility between phases and the use of the Cauchy-Born
rule. This tensor is difficult to measure directly from experiment. We give an
algorithm for the determination of the transformation stretch tensor from x-ray
measurements of structure and lattice parameters. When evaluated on some
traditional and emerging phase transformations the algorithm gives unexpected
results.Comment: 3 figures, 1 tabl
A disciplinary commons for database teaching
This paper discusses the experience of taking part in a disciplinary commons devoted to the teaching of database systems. It will discuss the structure of a disciplinary commons and our experience of the database version
Revealing per-grain and neighbourhood stress interactions of a deforming ferritic steel via three-dimensional X-ray diffraction
The structural performance of polycrystalline alloys is strongly controlled by the characteristics of individual grains and their interactions, motivating this study to understand the dynamic micromechanical response within the microstructure. Here, a high ductility single-phase ferritic steel during uniaxial deformation is explored using three-dimensional X-ray diffraction. Grains well aligned for dislocation slip are shown to possess a wide intergranular stress range, controlled by per-grain dependent hardening activity. Contrariwise, grains orientated poorly for slip have a narrow stress range. A grain neighbourhood effect is observed of statistical significance: the Schmid factor of serial adjoining grains influences the stress state of a grain of interest, whereas parallel neighbours are less influential. This phenomenon is strongest at low plastic strains, with the effect diminishing as grains rotate during plasticity to eliminate any orientation dependent load shedding. The ability of the ferrite to eliminate such neighbourhood interactions is considered key to the high ductility possessed by these materials
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