Molecular dynamics (MD) simulations confirm that normal grain boundary (GB) motion must often be coupled to tangential translation of grains and will then produce shear deformation of the lattice ...traversed by the GB. Conversely, shear stresses applied to a GB can induce its normal motion. Using 0
0
1 symmetrical tilt GBs in copper as a model, the coupling factor
β between the GB motion and grain translations has been calculated by MD simulations over the entire misorientation range and a wide range of temperatures. The coupling factor is multivalued, can be positive or negative, and shows an abrupt switch from one branch to another at a tilt angle of about 35°. At high temperatures the response of high-angle GBs to shear changes from coupling to sliding until coupling disappears. No sliding is observed for low-angle GBs up to near the melting point. A geometric model of coupling proposed in this work predicts the misorientation dependence of
β in excellent agreement with MD results and relates the multivalued character of
β to the point symmetry of the crystal. Two kinds of low-angle GBs with different dislocations occur when the tilt angle is small and again when it approaches 90°. In these limits, the multiplicity of
β is explained by different Burgers vectors of the dislocations. The results of this work are summarized as a temperature–misorientation diagram of mechanical responses of GBs. Unsolved problems and future work in this area are discussed.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
We postulate that almost any motion of an interface between two crystals can produce a coupled tangential motion of the two crystals relative to each other which is proportional to the normal motion ...of the interface. Such translations can produce grain rotations; the special case of the rotations of shrinking included circular cylindrical grains which increase misorientation, as seen in the molecular dynamics simulations, is reinterpreted with this postulate. When this postulate is added to other principles of interface motion, several phenomena associated with grain boundary mechanics and motion are unified into a single theoretical formulation: normal motion of a grain boundary resulting from a shear stress applied tangential to it which results in tangential motion and its converse, tangential motion resulting from coupling to normal motion; rigid sliding of one grain with respect to the other along a “greased” boundary; grain rotation due to tangential motion along curved grain boundaries, produced by either by sliding or by coupling to the normal motion. When the motion is driven by the reduction in the total surface free energy ∫
γ
d
a, if the grain rotation is due to sliding alone, then
γ itself (the surface free energy per unit area) is reduced; if it is due to coupled motion, then increases in
γ can occur if there is a large enough decrease in area that ∫
γ
d
a is decreased.
We explore the predictions for rotations of circular cylindrical grains moving to reduce total surface free energy. Among the surprising results is that certain combinations of coupling and surface free energy functions can result in increases rather than decreases in radii; these conditions, if achievable, can only occur far from small tilt misorientations. We also show that sliding alone must lead to misorientations with minimum
γ – or no misorientation – before the crystal shrinks to zero radius. For coupling alone, limiting misorientations (which need not, and often do not, coincide with minima in
γ) are never reached for non-zero radii. A more thorough exploration of sliding and coupling, including application to non-circular crystals and a variational model, is being published elsewhere.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Objective Genetic risk and outcome of psychoses (GROUP) is a 6 year longitudinal cohort study that focus on gene–environment vulnerability and resilience in patients with psychotic disorders, their ...unaffected family members and non-related controls. Its main aim is to elucidate etiological and pathogenetic factors that influence the onset and course of psychotic disorders. In this substudy, we will examine medication use over time, its relation with (the change in) metabolic syndrome status and effects on the brain. Methods A consortium of four university psychiatric centers and their affiliated mental health care institutions, conducted the GROUP study. At baseline, 1120 patients, 1057 siblings, 919 parents and 590 healthy controls were included. After inclusion, participants, except parents, were evaluated again after three and six years of follow-up. Extensive assessment of genetic factors, environmental factors, medication use, metabolic parameters and outcome were performed. Moreover, brain imaging was performed in a subset of participants, using a 1.5 Tesla MRI scanner. Results At baseline 65% of patients used atypical antipsychotics, 16% used conventional antipsychotics and 19% used clozapine. Siblings and controls used no antipsychotics. Forty-three percent of patients, 21.3% of siblings and 9.1% of controls used antidepressants; 43.9% of patients, 2.1% of siblings and none of the controls used a mood stabilizer. We are currently analyzing the medication data over time in relation to (change in) metabolic syndrome status and the effects on the brain. Conclusion GROUP is a longitudinal cohort study in patients with psychotic disorders, their healthy siblings and controls without psychosis. This naturalistic substudy examines medication use, its association with (change of) metabolic status and effects on the brain in subjects with (high risk of) psychosis.
Modern metallic materials are used extensively in a wide variety of applications, some of which are quite obvious (vehicles, cables, buildings and packaging) and others perhaps less so as in the ...critical structures of planes, skyscrapers, micro-electronic devises, nuclear and other energy plants. Many of the alloys used for these applications have undergone major transformations over the last 20 years. These transformations have been implemented to improve the material performances at minimum cost to the user. In many cases, if not most, they have resulted from advances in Thermo-Mechanical Processing - the set of operations by which basic materials are transformed into high quality components. Divided into three sections, the first section covers the microstructural science base of the subject, including the microstructure determined mechanical properties of metals. The second section deals with the current mechanical technology of plastic forming of metals. The concluding section illustrates the interaction of the first two disciplines in a series of case studies of successful current TMP processing and also looks ahead to possible new developments in the field. This book aims to fill this gap between two scientific approaches and illustrate also their successful linkage by the use of suitable modern case studies.
* Covers both physical metallurgy and metals processing* Links basic science to real everyday applications* Written by four internationally-known experts in the field
Introduction
Physical activity (PA) interventions can improve mental and physical health in people with mental illness, especially when delivered by qualified exercise professionals. Also, the ...behaviour, engagement and support of referring mental healthcare professionals (HCP) seems essential, but research is scarce.
Objectives
Studying the physical fitness and PA of HCP and the relationship with their attitudes and referral practices related to PA interventions
Methods
HCP at the Dutch Association for Psychiatry conference (2019) were invited to an online questionnaire (demographic/work characteristics, stress, PA levels, knowledge/attitudes regarding PA and referral practices) and cycle ergometer test. Linear and logistic regression were used to study the strongest associations.
Results
115 HCP completed the questionnaire. 40 also completed the ergometer test. 43% (n=50) met the national PA guidelines (≥150min moderate-to-vigorous PA and ≥2x bone/muscle-strengthening exercises a week). Women, HCP in training and HCP with more stress were less active and less likely to meet PA guidelines. HCP with personal experience with an exercise professional were more active and met guidelines more often. Knowledge/attitudes on physical health and PA were positive. Patients were more often referred to PA interventions by HCP who met PA guidelines (OR=2.56, 95%BI=0.85–7.13) or had higher beliefs that exercise professionals can increase adherence to PA interventions (OR=3.72, 95%BI=1.52–9.14).
Conclusions
It’s positive that HCP report importance and relevance of PA in mental healthcare. Although there is strong evidence for PA interventions in the treatment of people with mental illness, referral to such interventions can partly depend on the PA behaviour and attitude of patients’ physician/clinician.
Disclosure
No significant relationships.
Introduction
People with mental illness (MI) have a reduced life expectancy compared to the general population, mostly attributable to somatic diseases caused by poor physical health. Lifestyle ...factors (exercise, sleep, diet, substance use) are associated with poor physical and mental health. Although lifestyle factors, and physical and mental health are believed to be interconnected, research has mainly focused on one-sided relationships. Currently, we are implementing a lifestyle focussed approach in treatment, in which we assess lifestyle factors as well as physical and mental health of people with MI on a large scale (˜850 places of residence).
Objectives
To investigate the association between lifestyle factors, and physical and mental health in people with MI.
Methods
Baseline data from an open cohort cluster randomized stepped wedge study. Lifestyle factors (exercise, sleep, diet, substance use), physical health, medication use and psychological health (symptoms, quality of life) were assessed using data from patient files and questionnaires. Associations will be analysed with network analyses.
Results
First results (N≈1600) show that 54% of patients have high blood pressure, 51% have excessive waist circumference, 46% are experiencing sleep problems, 71% smoke and 88% do not meet exercise guidelines. Patients experience a lower quality of life compared to the general population.
Conclusions
Initial results show that patients have poor physical health, low quality of life and an unhealthy lifestyle. Further analyses are currently being conducted to gain insight in the complex pattern between lifestyle factors, and physical and mental health. This can contribute to the improvement of routine clinical care.
Disclosure
No significant relationships.
There is convincing evidence that schizophrenia is characterised by progressive brain volume changes during the course of the illness. In a large longitudinal study it was shown that different ...age-related trajectories of brain tissue loss are present in patients compared to healthy subjects, suggesting that brain maturation that occurs in the third and fourth decade of life is abnormal in schizophrenia. However, studies show that medication intake and cannabis use are important confounding factors when interpreting brain volume (change) abnormalities. Indeed, continues use of cannabis, but not cigarette smoking, is associated to a more pronounced loss of grey matter in the anterior cingulated and the prefrontal cortex. Atypical antipsychotics have been found to be related to smaller decreases in tissue loss. Moreover, independent of antipsychotic medication intake, the brain volume abnormalities appear associated to the outcome of the illness.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
The Frank-Bilby equation (FBE) can give many solutions for the dislocation content of a grain boundary (GB); most of them are considered to have little physical reality except in limited ranges of ...the angles which characterize low-angle GBs. We explore two such solutions, each of which is an accurate description for a different low-angle tilt GB with the same tilt axis. We develop a model that uses the two solutions to predict the coupling factor between normal motion and the shear strain produced by any (low- or high-angle) GB. Within this model, the two FBE solutions give rise to two possible modes of coupled GB motion which for the same GB under the same stress differ in direction of motion.
Using molecular dynamics simulations we confirm our model. We find positive and/or negative coupled GB motion for all misorientation angles, and the model gives accurate predictions for the shear produced even by high-angle GBs where individual dislocations cannot be resolved. At low temperatures dual behaviour is observed for the same high-angle GB and applied stress: both coupling modes are found with a switch between them after some time. This switch signifies a change in the effective dislocation content. Dual behaviour indicates that both solutions for the dislocation content can be meaningful for the same GB. At higher temperatures only one mode is seen for each GB under the same shear stress, and the switch between the two modes seems to occur discontinuously at some high misorientation angle.
Full text
Available for:
BFBNIB, GIS, IJS, KISLJ, NUK, PNG, UL, UM, UPUK
Introduction
People with mental illness (MI) have a reduced life expectancy compared to the general population, mostly attributable to somatic diseases caused by poor physical health. Modifiable ...lifestyle factors are increasingly associated with the onset of somatic diseases in people with MI. Despite the increasing evidence for the efficacy of lifestyle interventions there is little change in routine clinical care. This discrepancy is referred to as the implementation gap and has caused a need for effectiveness and implementation research in real-world settings.
Objectives
This study investigates the health outcomes and implementation of a multidisciplinary lifestyle focused approach in treatment of inpatients with mental illness (MULTI+).
Methods
This is an open cohort stepped wedge cluster randomized trial in inpatients psychiatric wards of GGz Centraal. Three clusters are randomly allocated to one of the three pre-defined steps to integrate MULTI+. MULTI+ can be tailored to fit individual psychiatric wards and includes 10 core components aimed at improving lifestyle factors. The primary outcome is to investigate whether there is a greater decrease in the QRISK3 cardiovascular risk score after receiving MULTI+ as compared to treatment as usual. Secondary outcomes include somatic and mental health outcomes, lifestyle factors, and implementation factors.
Results
First results expected in 2022.
Conclusions
To our knowledge, this will be the first large-scale study evaluating the long-term effects of a multidisciplinary, multicomponent approach aimed at improving lifestyle factors. We expect that this approach will increase long-term sustainability and can serve as a potential blueprint for future implementation of lifestyle interventions to improve routine clinical care.
Disclosure
No significant relationships.
