69 research outputs found
Design and optimization of a 3-DOF planar MEMS stage with integrated thermal position sensors
This work presents the design and optimization of a large stroke planar positioning stage in a single-mask MEMS fabrication process. Electrostatic comb-drive actuators were used to control the position and rotation of the 3-DOF stage. Thermal displacement sensors are integrated to provide feedback. Simulations show that we are able to reach a +/-120mm range of motion and +/-30 degrees of rotation.
Preliminary measurements were performed which validated our models
Linear stability analysis of resonant periodic motions in the restricted three-body problem
The equations of the restricted three-body problem describe the motion of a
massless particle under the influence of two primaries of masses and
, , that circle each other with period equal to
. When , the problem admits orbits for the massless particle that
are ellipses of eccentricity with the primary of mass 1 located at one of
the focii. If the period is a rational multiple of , denoted ,
some of these orbits perturb to periodic motions for . For typical
values of and , two resonant periodic motions are obtained for . We show that the characteristic multipliers of both these motions are given
by expressions of the form in the limit . The coefficient is analytic in at and
C(e,p,q)=O(e^{\abs{p-q}}). The coefficients in front of e^{\abs{p-q}},
obtained when is expanded in powers of for the two resonant
periodic motions, sum to zero. Typically, if one of the two resonant periodic
motions is of elliptic type the other is of hyperbolic type. We give similar
results for retrograde periodic motions and discuss periodic motions that
nearly collide with the primary of mass
Associations of within-individual changes in working conditions, health behaviour and BMI with work ability and self-rated health:a fixed effects analysis among Dutch workers
OBJECTIVES: This study assessed the associations of (1) within-individual improvements and (2) within-individual deteriorations in working conditions, health behaviour and body mass index (BMI) with changes in work ability and self-rated health among workers. DESIGN: Prospective cohort study. SETTING: The Netherlands. PARTICIPANTS: Persons in paid employment, aged 45-64 years, who participated in the Dutch Study on Transitions in Employment, Ability and Motivation (STREAM) between 2010 and 2017, and improved or deteriorated at least once with respect to working conditions (psychological and emotional job demands, autonomy, social support, physical workload), health behaviour (moderate and vigorous physical activity, smoking status), or BMI between any of two consecutive measurements during the 7-year follow-up. PRIMARY AND SECONDARY OUTCOME MEASURES: Changes in self-reported work ability on a scale from 0 to 10 (1st item of the work ability index) and self-rated health on a scale from 1 to 5 (SF-12). RESULTS: Of the 21 856 STREAM participants, ultimately 14 159 workers were included in the fixed effects analyses on improvements (N=14 045) and deteriorations (N=14 066). Workers with deteriorated working conditions decreased in work ability (β's: -0.21 (95% CI: -0.25 to -0.18) to -0.28 (95% CI: -0.33 to -0.24)) and health (β's: -0.07 (95% CI: -0.09 to -0.06) to -0.10 (95% CI: -0.12 to -0.08)), whereas improvements were to a lesser extent associated with increased work ability (β's: 0.06 (95% CI: 0.02 to 0.09) to 0.11 (95% CI: 0.06 to 0.16)) and health (β's: 0.02 (95% CI: 0.00 to 0.03) to 0.04 (95% CI: 0.02 to 0.06)). Workers with increased BMI or decreased physical activity reduced in work ability and health. Likewise, decreased BMI or increased vigorous physical activity was associated with improved health. An increase in moderate or vigorous physical activity was modestly associated with a reduced work ability. Quitting smoking was associated with reduced work ability and health. CONCLUSIONS: Compared with improvements, preventing deteriorations in working conditions, health behaviour and BMI, might be more beneficial for work ability and workers' health
Novel genetic loci associated with hippocampal volume
The hippocampal formation is a brain structure integrally involved in episodic memory, spatial navigation, cognition and stress responsiveness. Structural abnormalities in hippocampal volume and shape are found in several common neuropsychiatric disorders. To identify the genetic underpinnings of hippocampal structure here we perform a genome-wide association study (GWAS) of 33,536 individuals and discover six independent loci significantly associated with hippocampal volume, four of them novel. Of the novel loci, three lie within genes (ASTN2, DPP4 and MAST4) and one is found 200 kb upstream of SHH. A hippocampal subfield analysis shows that a locus within the MSRB3 gene shows evidence of a localized effect along the dentate gyrus, subiculum, CA1 and fissure. Further, we show that genetic variants associated with decreased hippocampal volume are also associated with increased risk for Alzheimer's disease (rg =-0.155). Our findings suggest novel biological pathways through which human genetic variation influences hippocampal volume and risk for neuropsychiatric illness
The influence of unhealthy behaviours on early exit from paid employment among workers with a chronic disease: A prospective study using the Lifelines cohort
Objectives: This study examined the risk of unhealthy behaviours and the additive effects of multiple unhealthy behaviours on exit from paid employment among workers with a chronic disease and investigated effect modification by gender and educational level. Methods: Data from the Lifelines cohort, collected between 2006 and 2013, were enriched with registry data from Statistics Netherlands with up to 11 years follow-up. Workers with a chronic disease were selected (n = 11,467). The influence of unhealthy b
Thrombus radiomics in patients with anterior circulation acute ischemic stroke undergoing endovascular treatment
Background Thrombus radiomics (TR) describe complex shape and textural thrombus imaging features. We aimed to study the relationship of TR extracted from non-contrast CT with procedural and functional outcome in endovascular-treated patients with acute ischemic stroke. Methods Thrombi were segmented on thin-slice non-contrast CT (0.75). Random forest models using TR in addition or as a substitute to baseline clinical variables (CV) and manual thrombus measurements (MTM) were trained with 499 patients and evaluated on 200 patients for predicting successful reperfusion (extended Thrombolysis in Cerebral Ischemia (eTICI) >= 2B), first attempt reperfusion, reperfusion within three attempts, and functional independence (modified Rankin Scale (mRS) = 2B, number of attempts to eTICI >= 2B, and 90-day mRS with ordinal logistic regression. Results Random forest models using TR, CV or MTM had comparable predictive performance. Thrombus texture (inverse difference moment normalized) was independently associated with reperfusion (adjusted common OR (acOR) 0.85, 95% CI 0.72 to 0.99). Thrombus volume and texture were also independently associated with the number of attempts to successful reperfusion (acOR 1.36, 95% CI 1.03 to 1.88 and acOR 1.24, 95% CI 1.04 to 1.49). Conclusions TR describing thrombus volume and texture were associated with more attempts to successful reperfusion. Compared with models using CV and MTM, TR had no added value for predicting procedural and functional outcome
The ARID1B spectrum in 143 patients: from nonsyndromic intellectual disability to Coffin–Siris syndrome
Purpose: Pathogenic variants in ARID1B are one of the most frequent causes of intellectual disability (ID) as determined by large-scale exome sequencing studies. Most studies published thus far describe clinically diagnosed Coffin–Siris patients (ARID1B-CSS) and it is unclear whether these data are representative for patients identified through sequencing of unbiased ID cohorts (ARID1B-ID). We therefore sought to determine genotypic and phenotypic differences between ARID1B-ID and ARID1B-CSS. In parallel, we investigated the effect of different methods of phenotype reporting. Methods: Clinicians entered clinical data in an extensive web-based survey. Results: 79 ARID1B-CSS and 64 ARID1B-ID patients were included. CSS-associated dysmorphic features, such as thick eyebrows, long eyelashes, thick alae nasi, long and/or broad philtrum, small nails and small or absent fifth distal phalanx and hypertrichosis, were observed significantly more often (p < 0.001) in ARID1B-CSS patients. No other significant differences were identified. Conclusion: There are only minor differences between ARID1B-ID and ARID1B-CSS patients. ARID1B-related disorders seem to consist of a spectrum, and patients should be managed similarly. We demonstrated that data collection methods without an explicit option to report the absence of a feature (such as most Human Phenotype Ontology-based methods) tended to underestimate gene-related features
Exploration of shared genetic architecture between subcortical brain volumes and anorexia nervosa
In MRI scans of patientswith anorexia nervosa (AN), reductions in brain volume are often apparent. However, it is unknownwhether such brain abnormalities are influenced by genetic determinants that partially overlap with those underlyingAN. Here, we used a battery of methods (LD score regression, genetic risk scores, sign test, SNP effect concordance analysis, and Mendelian randomization) to investigate the genetic covariation between subcortical brain volumes and risk for AN based on summary measures retrieved from genome-wide association studies of regional brain volumes (ENIGMA consortium, n = 13,170) and genetic risk for AN (PGC-ED consortium, n = 14,477). Genetic correlationsrangedfrom-0.10to0.23(allp > 0.05). Thereweresomesigns ofaninverseconcordance between greater thalamus volume and risk for AN (permuted p = 0.009, 95% CI: [ 0.005, 0.017]). A genetic variant in the vicinity of ZW10, a gene involved in cell division, and neurotransmitter and immune systemrelevant genes, in particularDRD2, was significantly associated with AN only after conditioning on its association with caudate volume (pFDR = 0.025). Another genetic variant linked to LRRC4C, important in axonal and synaptic development, reached significance after conditioning on hippocampal volume (pFDR = 0.021). In this comprehensive set of analyses and based on the largest available sample sizes to date, there was weak evidence for associations between risk for AN and risk for abnormal subcortical brain volumes at a global level (that is, common variant genetic architecture), but suggestive evidence for effects of single genetic markers. Highly powered multimodal brain-and disorder-related genome-wide studies are needed to further dissect the shared genetic influences on brain structure and risk for AN.Stress-related psychiatric disorders across the life spa
Improving in vivo predictions from in vitro hepatocyte models: model selection, protein effects, and transporter regulation
Changes in Physical Activity Among Postpartum Overweight and Obese Women: Results from the KAN-DO Study
10.1080/03630242.2013.769482Women and Health533317-334WOHE
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