669 research outputs found
A scalable parallel finite element framework for growing geometries. Application to metal additive manufacturing
This work introduces an innovative parallel, fully-distributed finite element
framework for growing geometries and its application to metal additive
manufacturing. It is well-known that virtual part design and qualification in
additive manufacturing requires highly-accurate multiscale and multiphysics
analyses. Only high performance computing tools are able to handle such
complexity in time frames compatible with time-to-market. However, efficiency,
without loss of accuracy, has rarely held the centre stage in the numerical
community. Here, in contrast, the framework is designed to adequately exploit
the resources of high-end distributed-memory machines. It is grounded on three
building blocks: (1) Hierarchical adaptive mesh refinement with octree-based
meshes; (2) a parallel strategy to model the growth of the geometry; (3)
state-of-the-art parallel iterative linear solvers. Computational experiments
consider the heat transfer analysis at the part scale of the printing process
by powder-bed technologies. After verification against a 3D benchmark, a
strong-scaling analysis assesses performance and identifies major sources of
parallel overhead. A third numerical example examines the efficiency and
robustness of (2) in a curved 3D shape. Unprecedented parallelism and
scalability were achieved in this work. Hence, this framework contributes to
take on higher complexity and/or accuracy, not only of part-scale simulations
of metal or polymer additive manufacturing, but also in welding, sedimentation,
atherosclerosis, or any other physical problem where the physical domain of
interest grows in time
Recommended from our members
Interpretation of ambiguous situations: evidence for a dissociation between social and physical threat in Williams syndrome
There is increasing evidence that Williams syndrome (WS) is associated with elevated anxiety that is non-social in nature, including generalised anxiety and fears. To date very little research has examined the cognitive processes associated with this anxiety. In the present research, attentional bias for non-social threatening images in WS was examined using a dot-probe paradigm. Participants were 16 individuals with WS aged between 13 and 34 years and two groups of typically developing controls matched to the WS group on chronological age and attentional control ability respectively. The WS group exhibited a significant attention bias towards threatening images. In contrast, no bias was found for group matched on attentional control and a slight bias away from threat was found in the chronological age matched group. The results are contrasted with recent findings suggesting that individuals with WS do not show an attention bias for threatening faces and discussed in relation to neuroimaging research showing elevated amygdala activation in response to threatening non-social scenes in WS
Outcomes of Operatively Treated Acute Knee Dislocations
Knee dislocation is a complex and rare injury often presenting in the context of high velocity trauma. The aim of this study is to establish the subjective outcomes of surgically treated knee dislocations. A total of 20 knees dislocations treated by open repair were reviewed. Their progress and outcomes were assessed by using a modified Lysholm score questionnaire. Data was obtained on patient demographics, details of injury, investigation, treatment, rehabilitation, 24 months objective outcome and subjective outcomes. Six patients had a vascular deficit and six had neurological deficits. The median range of motion was 0°-100°. Patients with an initially lower pre-injury level of function were able to return an activity level comparable to their pre-injury status. 22% of competitive athletes retuned to competitive sports. 38% of patients undertaking heavy activity returned to comparable pre-injury level of activity and 67% of patients undertaking moderate level of activity before injury returned to a comparable level after repair. 68% regularly had problems running, 70% problem squatting, 40% swelling and 42% problem with stairs. Most patients however did not have locking of the knee or problems with knees giving way. Patients pain scores decreased over time to an acceptable level. Despite the severity of the injury, majority of patients achieved a satisfactory outcome, although none of the patients reached the same level of function as before the injury. 80% of the patients were satisfied with their outcome. All dissatisfied patients suffered postoperative complications
Parity-Violating Electron Scattering from 4He and the Strange Electric Form Factor of the Nucleon
We have measured the parity-violating electroweak asymmetry in the elastic
scattering of polarized electrons from ^4He at an average scattering angle
= 5.7 degrees and a four-momentum transfer Q^2 = 0.091 GeV^2. From
these data, for the first time, the strange electric form factor of the nucleon
G^s_E can be isolated. The measured asymmetry of A_PV = (6.72 +/- 0.84 (stat)
+/- 0.21 (syst) parts per million yields a value of G^s_E = -0.038 +/- 0.042
(stat) +/- 0.010 (syst), consistent with zero
Self-reported competence, attitude and approach of physicians towards patients with dementia in ambulatory care: Results of a postal survey
<p>Abstract</p> <p>Background</p> <p>Caring for patients with dementia is a demanding task. Little is known as to whether physicians feel competent enough to perform this task or whether a lack of self-perceived competence influences attitudes and professional approach. Even less is known with respect to potential differences between general practitioners (GPs) and specialists. The purpose of this study was to investigate the interrelationship between the self-perceived competence, attitude and professional approach of physicians in ambulatory care in Germany. A further aim was to compare GPs and specialists with regard to differences in these areas.</p> <p>Methods</p> <p>A standardised postal survey was sent to 389 GPs and 239 neurologists and psychiatrists in six metropolitan areas in Germany. The 49-item questionnaire consisted of attitudinal statements to be rated on a Likert-type scale. Return rates were 54 percent for GPs and 40 percent for specialists. Statistical methods used to analyze data included correlation analysis, cluster analysis and ordinal regression analysis.</p> <p>Results</p> <p>No differences were found between GPs and specialists with regard to their general attitude towards caring for patients with dementia. Approximately 15 percent of both disciplines showed a clearly negative attitude. Self-reported competence was strongly associated with general attitude. In particular among GPs, and less so among specialists, a strong positive association was found between self-reported competence, general attitude and professional approach (e.g. early detection, active case finding and cooperation with caregivers). Differences between GPs and specialists were smaller than expected and appear to predominantly reflect task differences within the German health care system.</p> <p>Conclusion</p> <p>Training opportunities which enable in particular GPs to enhance not only their competence but also their general attitude towards dementia care would appear to be beneficial and might carry positive consequences for patients and their caregivers.</p
Relationship between atomoxetine plasma concentration, treatment response and tolerability in attention-deficit/hyperactivity disorder and comorbid oppositional defiant disorder
The purpose of this study was to examine whether atomoxetine plasma concentration predicts attention-deficit/hyperactivity disorder (ADHD) or oppositional defiant disorder (ODD) response. This post-hoc analysis assessed the relationship between atomoxetine plasma concentration and ADHD and ODD symptoms in patients (with ADHD and comorbid ODD) aged 6–12 years. Patients were randomly assigned to atomoxetine 1.2 mg/kg/day (n = 156) or placebo (n = 70) for 8 weeks (Study Period II). At the end of 8 weeks, ODD non-remitters (score >9 on the SNAP-IV ODD subscale and CGI-I > 2) with atomoxetine plasma concentration <800 ng/ml at 2 weeks were re-randomized to either atomoxetine 1.2 mg/kg/day or 2.4 mg/kg/day for an additional 4 weeks (Study Period III). ODD remitters and non-remitters with plasma atomoxetine ≥800 ng/ml remained on 1.2 mg/kg/day atomoxetine for 4 weeks. Patients who received atomoxetine, completed Study Period II, and entered Study Period III were included in these analyses. All the groups demonstrated improvement on the SNAP-IV ODD and ADHD-combined subscales (P < .001). At the end of Study Periods II and III, ODD and ADHD improvement was significantly greater in the remitter group compared with the non-remitter groups. Symptom improvement was numerically greater in the non-remitter (2.4 mg/kg/day compared with the non-remitter 1.2 mg/kg/day) group. Atomoxetine plasma concentration was not indicative of ODD and ADHD improvement after 12 weeks of treatment. ADHD and ODD symptoms improved in all the groups with longer duration on atomoxetine. Results suggest atomoxetine plasma concentration does not predict ODD and ADHD symptom improvement. However, a higher atomoxetine dose may benefit some patients
A Defined, Feeder-Free, Serum-Free System to Generate In Vitro Hematopoietic Progenitors and Differentiated Blood Cells from hESCs and hiPSCs
Human ESC and iPSC are an attractive source of cells of high quantity and purity to be used to elucidate early human development processes, for drug discovery, and in clinical cell therapy applications. To efficiently differentiate pluripotent cells into a pure population of hematopoietic progenitors we have developed a new 2-dimentional, defined and highly efficient protocol that avoids the use of feeder cells, serum or embryoid body formation. Here we showed that a single matrix protein in combination with growth factors and a hypoxic environment is sufficient to generate from pluripotent cells hematopoietic progenitors capable of differentiating further in mature cell types of different lineages of the blood system. We tested the differentiation method using hESCs and 9 iPSC lines generated from different tissues. These data indicate the robustness of the protocol providing a valuable tool for the generation of clinical-grade hematopoietic cells from pluripotent cells
Aquatic Birnavirus-Induced ER Stress-Mediated Death Signaling Contribute to Downregulation of Bcl-2 Family Proteins in Salmon Embryo Cells
Aquatic birnavirus induces mitochondria-mediated cell death, but whether connects to endoplasmic reticulum (ER) stress is still unknown. In this present, we characterized that IPNV infection triggers ER stress-mediated cell death via PKR/eIF2α phosphorylation signaling for regulating the Bcl-2 family protein expression in fish cells. The IPNV infection can induce ER stress as follows: (1) ER stress sensor ATF6 cleavaged; (2) ER stress marker GRP78 upregulation, and (3) PERK/eIF2αphosphorylation. Then, the IPNV-induced ER stress signals can induce the CHOP expression at early (6 h p.i.) and middle replication (12 h p.i.) stages. Moreover, IPNV-induced CHOP upregulation dramatically correlates to apparently downregulate the Bcl-2 family proteins, Bcl-2, Mcl-1 and Bcl-xL at middle replication stage (12 h p.i.) and produces mitochondria membrane potential (MMP) loss and cell death. Furthermore, with GRP78 synthesis inhibitor momitoxin (VT) and PKR inhibitor 2-aminopurine (2-AP) treatment for blocking GRP78 expression and eIF2α phosphorylation, PKR/PERK may involve in eIF2α phosphorylation/CHOP upregulation pathway that enhances the downstream regulators Bcl-2 family proteins expression and increased cell survival. Taken together, our results suggest that IPNV infection activates PKR/PERK/eIF2α ER stress signals for regulating downstream molecules CHOP upregulation and Bcl-2 family downregulation that led to induce mitochondria-mediated cell death in fish cells, which may provide new insight into RNA virus pathogenesis and disease
Acute kidney disease and renal recovery : consensus report of the Acute Disease Quality Initiative (ADQI) 16 Workgroup
Consensus definitions have been reached for both acute kidney injury (AKI) and chronic kidney disease (CKD) and these definitions are now routinely used in research and clinical practice. The KDIGO guideline defines AKI as an abrupt decrease in kidney function occurring over 7 days or less, whereas CKD is defined by the persistence of kidney disease for a period of > 90 days. AKI and CKD are increasingly recognized as related entities and in some instances probably represent a continuum of the disease process. For patients in whom pathophysiologic processes are ongoing, the term acute kidney disease (AKD) has been proposed to define the course of disease after AKI; however, definitions of AKD and strategies for the management of patients with AKD are not currently available. In this consensus statement, the Acute Disease Quality Initiative (ADQI) proposes definitions, staging criteria for AKD, and strategies for the management of affected patients. We also make recommendations for areas of future research, which aim to improve understanding of the underlying processes and improve outcomes for patients with AKD
Thyroid peroxidase forms thionamide-sensitive homodimers: relevance for immunomodulation of thyroid autoimmunity
Thyroid peroxidase (TPO) is the key enzyme in thyroid hormone production and a universal autoantigen in Graves’ and other autoimmune thyroid diseases. We wished to explore the expression of TPO and whether it was affected by thionamide antithyroid drugs. We studied recombinant TPO, stably expressed by a Chinese hamster ovary cell line (CHO-TPO) and transiently expressed TPO-enhanced green fluorescent protein (eGFP) and -FLAG fusion proteins. Immunoblotting of CHO-TPO cell extracts showed high-molecular weight (HMW) TPO isoforms that were resistant to reduction, as well as 110 kDa monomeric TPO. Co-immunoprecipitation and enzyme-linked-immunosorbent assay (ELISA) binding studies of FLAG- and eGFP-tagged TPO demonstrated TPO dimerisation. CHO-TPO cells cultured in methimazole (MMI) for 10 days showed a significant reduction in HMW-TPO isoforms at MMI concentrations of 1 µM and above (p < 0.01), whereas monomeric TPO expression was unchanged. We observed a similar reduction in HMW-TPO in CHO-TPO cells cultured in propylthiouracil (10 µM and above). Binding of Graves’ disease patient sera and TPO-Fabs to enzymatically active TPO that was captured onto solid phase was not abrogated by MMI. The cellular localisation of TPO in CHO-TPO cells was unchanged by MMI treatment. Our demonstration of homodimeric TPO and the reduction in HMW-TPO isoforms during thionamide treatment of CHO-TPO cells shows, for the first time, an effect of thionamides on TPO structure. This suggests a structural correlate to the effect of thionamides on TPO enzymatic activity and opens up a novel potential mechanism for thionamide immunomodulation of autoimmune thyroid disease
- …