448 research outputs found
A conceptual exoskeleton shoulder design for the assistance of upper limb movement
© Springer International Publishing AG, part of Springer Nature 2018. There is an increased interest on wearable technologies for rehabilitation and human augmentation. Systems focusing on the upper limbs are attempting to replicate the musculoskeletal structures found in humans, reproducing existing behaviors and capabilities. The current work is expanding on existing systems with a novel design that ensures the maximum range of motion while at the same time allowing for lockable features ensuring higher manipulation payloads at minimum energy and fatigue costs. An analysis of the biomechanics of the shoulder is being done and a detailed system design for structural as well actuation elements of a parallel mechanism is given. The benefits for the use are discussed of reduced weight, maximum range of motion at minimum energy cost
The Features of the Synovium in Early Rheumatoid Arthritis According to the 2010 ACR/EULAR Classification Criteria
OBJECTIVES: It has been shown in early arthritis cohorts that the 2010 ACR/EULAR criteria for rheumatoid arthritis (RA) enable an earlier diagnosis, perhaps at the cost of a somewhat more heterogeneous patient population. We describe the features of synovial inflammation in RA patients classified according to these new criteria. METHODS: At baseline, synovial tissue biopsy samples were obtained from disease-modifying antirheumatic drug (DMARD)-naïve early RA patients (clinical signs and symptoms <1 year). Synovial tissue was analyzed for cell infiltration, vascularity, and expression of adhesion molecules. Stained sections were evaluated by digital image analysis. Patients were classified according to the two different sets of classification criteria, autoantibody status, and outcome. FINDINGS: Synovial tissue of 69 RA patients according to 2010 ACR/EULAR criteria was analyzed: 56 patients who fulfilled the criteria for RA at baseline and 13 who were initially diagnosed as undifferentiated arthritis but fulfilled criteria for RA upon follow up. The synovium at baseline was infiltrated by plasma cells, macrophages, and T cells as well as other cells, and findings were comparable to those when patients were selected based on the 1987 ACR criteria for RA. There was no clear cut difference in the characteristics of the synovium between RA patients initially diagnosed as undifferentiated arthritis and those who already fulfilled classification criteria at baseline. CONCLUSION: The features of synovial inflammation are similar when the 2010 ACR/EULAR classification criteria are used compared to the 1987 ACR criteria
Рідке мило на основі соапстоків після нейтралізації олій та жирів в нейтралізуючому розчині, що містить етанол
Development and application of statistical models for medical scientific researc
Analysis of reflex modulation with a biologically realistic neural network
In this study, a neuromusculoskeletal model was built to give insight into the mechanisms behind the modulation of reflexive feedback strength as experimentally identified in the human shoulder joint. The model is an integration of a biologically realistic neural network consisting of motoneurons and interneurons, modeling 12 populations of spinal neurons, and a one degree-of-freedom musculoskeletal model, including proprioceptors. The model could mimic the findings of human postural experiments, using presynaptic inhibition of the Ia afferents to modulate the feedback gains. In a pathological case, disabling one specific neural connection between the inhibitory interneurons and the motoneurons could mimic the experimental findings in complex regional pain syndrome patients. It is concluded that the model is a valuable tool to gain insight into the spinal contributions to human motor control. Applications lay in the fields of human motor control and neurological disorders, where hypotheses on motor dysfunction can be tested, like spasticity, clonus, and tremor
Therapeutic interception in individuals at risk of rheumatoid arthritis to prevent clinically impactful disease
Multiple clinical trials for rheumatoid arthritis (RA) prevention have been completed. Here, we set out to report on the lessons learnt from these studies. Researchers who conducted RA prevention trials shared the background, rationale, approach and outcomes and evaluated the lessons learnt to inform the next generation of RA prevention trials. Individuals at risk of RA can be identified through population screening, referrals to musculoskeletal programmes and by recognition of arthralgia suspicious for RA. Clinical trials in individuals at risk for future clinical RA have demonstrated that limited courses of corticosteroids, atorvastatin and hydroxychloroquine do not alter incidence rates of clinical RA; however, rituximab delays clinical RA onset, and methotrexate has transient effects in individuals who are anticitrullinated protein antibody-positive with subclinical joint inflammation identified by imaging. Abatacept delays clinical RA onset but does not fully prevent onset of RA after treatment cessation. Additionally, subclinical joint inflammation and symptoms appear responsive to interventions such as methotrexate and abatacept. To advance prevention, next steps include building networks of individuals at risk for RA, to improve risk stratification for future RA and to understand the biological mechanisms of RA development, including potential endotypes of disease, which can be targeted for prevention, thus adopting a more precision-based approach. Future trials should focus on interceptions aimed at preventing clinical RA onset and which treat existing symptoms and imaging-defined subclinical inflammation. These trials may include advanced designs (eg, adaptive) and should be combined with mechanistic studies to further define pathophysiological drivers of disease development
A genome-wide association study of rheumatoid arthritis without antibodies against citrullinated peptides
Introduction. Rheumatoid arthritis (RA) patients can be classified based on presence or absence of anticitrullinated peptide antibodies (ACPA) in their serum. This heterogeneity among patients may reflect important biological differences underlying the disease process. To date, the majority of genetic studies have focused on the ACPA-positive group. Therefore, our goal was to analyse the genetic risk factors that contribute to ACPA-negative RA. Methods. We performed a large-scale genome-wide association study (GWAS) in three Caucasian European cohorts comprising 1148 ACPA-negative RA patients and 6008 controls. All patients were screened using the Illumina Human Cyto-12 chip, and controls were genotyped using different genome-wide platforms. Population-independent analyses were carried out by means of logistic regression. Meta-analysis with previously published data was performed as follow-up for selected signals (reaching a total of 1922 ACPA-negative RA patients and 7087 controls). Imputation of classical HLA alleles, aminoacid residues and single nucleotide polymorphisms was undertaken. Results. The combined analysis of the studied cohorts resulted in identification of a peak of association in the HLA-region and several suggestive non-HLA associations. Meta-analysis with previous reports confirmed the association of the HLA region with this subset and an observed association in the CLYBL locus remained suggestive. The imputation and deep interrogation of the HLA region led to identification of a two aminoacid model (HLA-B at position 9 and HLA-DRB1 at position 11) that accounted for the observed genome-wide associations in this region. Conclusions. Our study shed light on the influence of the HLA region in ACPA-negative RA and identified a suggestive risk locus for this condition
Molecular Assessment of Bacterial Vaginosis by Lactobacillus Abundance and Species Diversity
Background
To date, women are most often diagnosed with bacterial vaginosis (BV) using microscopy based Nugent scoring or Amsel criteria. However, the accuracy is less than optimal. The aim of the present study was to confirm the identity of known BV-associated composition profiles and evaluate indicators for BV using three molecular methods.
Methods
Evaluation of indicators for BV was carried out by 16S rRNA amplicon sequencing of the V5-V7 region, a tailor-made 16S rRNA oligonucleotide-based microarray, and a PCR-based profiling technique termed IS-profiling, which is based on fragment variability of the 16S-23S rRNA intergenic spacer region. An inventory of vaginal bacterial species was obtained from 40 females attending a Dutch sexually transmitted infection outpatient clinic, of which 20 diagnosed with BV (Nugent score 7–10), and 20 BV negative (Nugent score 0–3).
Results
Analysis of the bacterial communities by 16S rRNA amplicon sequencing revealed two clusters in the BV negative women, dominated by either Lactobacillus iners or Lactobacillus crispatus and three distinct clusters in the BV positive women. In the former, there was a virtually complete, negative correlation between L. crispatus and L. iners. BV positive subjects showed cluster profiles that were relatively high in bacterial species diversity and dominated by anaerobic species, including Gardnerella vaginalis, and those belonging to the Families of Lachnospiraceae and Leptotrichiaceae. Accordingly, the Gini-Simpson index of species diversity, and the relative abundance Lactobacillus species appeared consistent indicators for BV. Under the conditions used, only the 16S rRNA amplicon sequencing method was suitable to assess species diversity, while all three molecular composition profiling methods were able to indicate Lactobacillus abundance in the vaginal microbiota.
Conclusion
An affordable and simple molecular test showing a depletion of the genus Lactobacillus in combination with an increased species diversity of vaginal microbiota could serve as an alternative and practical diagnostic method for the assessment of BV
Decoupling of a Current-Biased Intrinsic Josephson Junction from its Environment
We have observed a dissipative phase diffusion branch in arrays of hysteretic
high-Tc intrinsic Josephson junctions. By comparing the data with a thermal
activation model we extract the impedance seen by the junction in which phase
diffusion is occurring. At the plasma frequency this junction is isolated from
its environment and it sees its own large (~ kilo Ohm) impedance. Our results
suggest that stacks of Josephson junctions may be used for isolation purposes
in the development of a solid state quantum computer
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