Purcell magneto-elastic swimmer controlled by an external magnetic field

International audienceThis paper focuses on the mechanism of propulsion of a Purcell swimmer whose segments are magnetized and react to an external magnetic field applied into the fluid. By an asymptotic analysis, we prove that it is possible to steer the swimmer along a chosen direction when the control functions are prescribed as an oscillating field. Moreover, we discuss what are the main obstructions to overcome in order to get classical controllability result for this system

Evaluation of the analytical variability of dipstick protein pads in canine urine

BackgroundThe dipstick is a first-line and inexpensive test that can exclude the presence of proteinuria in dogs. However, no information is available about the analytical variability of canine urine dipstick analysis. ObjectivesThe aim of this study was to assess the analytical variability in 2 dipsticks and the inter-operator variability in dipstick interpretation. MethodsCanine urine supernatants (n = 174) were analyzed with 2 commercially available dipsticks. Two observers evaluated each result blinded to the other observer and to the results of the other dipstick. Intra- and inter-assay variability was assessed in 5 samples (corresponding to the 5 different semi-quantitative results) tested 10 consecutive times over 5 consecutive days. The agreement between observers and between dipsticks was evaluated with Cohen's k test. ResultsIntra-assay repeatability was good (3/10 errors), whereas inter-assay variability was higher (from 1/5 to 4/5 discordant results). The concordance between the operators (k = 0.68 and 0.79 for the 2 dipsticks) and that of the dipsticks (k = 0.66 and 0.74 for the 2 operators) was good. However, 1 observer and 1 dipstick overestimated the results compared with the second observer or dipstick. In any case, discordant results accounted for a single unit of the semi-quantitative scale. ConclusionsAs for any other method, analytic variability may affect the semi-quantitation of urinary proteins when using the dipstick method. Subjective interpretation of the pad and, to a lesser extent, intrinsic staining properties of the pads could affect the results. Further studies are warranted to evaluate the effect of this variability on clinical decisions

Sexual distress and quality of life among women with bipolar disorder

Abstract Background Information on the association between bipolar disorder (BD), sexual satisfaction, sexual function, sexual distress and quality of life (QoL) is sparse. This study aims, in women with BD, to (i) investigate sexual dysfunction, sexual distress, general sexual satisfaction and QoL; (ii) explore whether sexual distress was related to affective symptoms and (iii) investigate whether QoL was associated with sexual distress. The study is a questionnaire survey in an outpatient cohort of women with BD using: Changes in Sexual Functioning Questionnaire, Female Sexual Distress Scale, Altman Self-Rating Mania Scale (ASRM), Major Depression Inventory (MDI) and The World Health Organisation Quality of Life-Brief. Results In total, 61 women (age range 19–63, mean 33.7 years) were recruited. Overall, 54% reported sexual distress (n = 33) and 39% were not satisfied with their sexual life (n = 24). Women with BD were significantly more sexually distressed in comparison with Danish women from the background population but they did not have a higher prevalence of impaired sexual function. Better sexual function was positively associated with ASRM scores while MDI scores were associated with more distress. Finally, the group of non-sexually distressed women with BD reported higher QoL scores compared with the sexually distressed group. Conclusions Women with BD exhibited a high prevalence of sexual distress and their sexual function seemed associated with their actual mood symptoms and perception of QoL

Modeling and steering magneto-elastic micro-swimmers inspired by the motility of sperm cells

Controlling artificial devices that mimic the motion of real microorganisms, is attracting increasing interest, both from the mathematical point of view and applications. A model for a magnetically driven slender micro-swimmer, mimicking a sperm cell is presented, supported by two examples showing how to steer it. Using the Resistive Force Theory (RTF) approach [J. Gray and J. Hancock, J. Exp. Biol. 32, 802 (1955)] to describe the hydrodynamic forces, the micro-swimmer can be described by a driftless affine control system where the control is an external magnetic field. Moreover we discuss through at first an asymptotic analysis and then by numerical simulations how to realize different kinds of paths