Mechanical design of NASA Ames Research Center vertical motion simulator

NASA has designed and is constructing a new flight simulator with large vertical travel. Several aspects of the mechanical design of this Vertical Motion Simulator (VMS) are discussed, including the multiple rack and pinion vertical drive, a pneumatic equilibration system, and the friction-damped rigid link catenaries used as cable supports

Active Mass Under Pressure

After a historical introduction to Poisson's equation for Newtonian gravity, its analog for static gravitational fields in Einstein's theory is reviewed. It appears that the pressure contribution to the active mass density in Einstein's theory might also be noticeable at the Newtonian level. A form of its surprising appearance, first noticed by Richard Chase Tolman, was discussed half a century ago in the Hamburg Relativity Seminar and is resolved here.Comment: 28 pages, 4 figure

Surviving critical illness: what is next? An expert consensus statement on physical rehabilitation after hospital discharge

Background: The study objective was to obtain consensus on physical therapy (PT) in the rehabilitation of critical illness survivors after hospital discharge. Research questions were: what are PT goals, what are recommended measurement tools, and what constitutes an optimal PT intervention for survivors of critical illness? Methods: A Delphi consensus study was conducted. Panelists were included based on relevant fields of expertise, years of clinical experience, and publication record. A literature review determined five themes, forming the basis for Delphi round one, which was aimed at generating ideas. Statements were drafted and ranked on a 5-point Likert scale in two additional rounds with the objective to reach consensus. Results were expressed as median and semi-interquartile range, with the consensus threshold set at ≤0.5. Results: Ten internationally established researchers and clinicians participated in this Delphi panel, with a response rate of 80 %, 100 %, and 100 % across three rounds. Consensus was reached on 88.5 % of the statements, resulting in a framework for PT after hospital discharge. Essential handover information should include information on 15 parameters. A core set of outcomes should test exercise capacity, skeletal muscle strength, function in activities of daily living, mobility, quality of life, and pain. PT interventions should include functional exercises, circuit and endurance training, strengthening exercises for limb and respiratory muscles, education on recovery, and a nutritional component. Screening tools to identify impairments in other health domains and referral to specialists are proposed. Conclusions: A consensus-based framework for optimal PT after hospital discharge is proposed. Future research should focus on feasibility testing of this framework, developing risk stratification tools and validating core outcome measures for ICU survivors

Idiopathic toe-walking in children, adolescents and young adults: a matter of local or generalised stiffness?

<p>Abstract</p> <p>Background</p> <p>Idiopathic Toe Walking (ITW) is present in children older than 3 years of age still walking on their toes without signs of neurological, orthopaedic or psychiatric diseases. ITW has been estimated to occur in 7% to 24% of the childhood population. To study associations between Idiopathic Toe Walking (ITW) and decrease in range of joint motion of the ankle joint. To study associations between ITW (with stiff ankles) and stiffness in other joints, muscle strength and bone density.</p> <p>Methods</p> <p>In a cross-sectional study, 362 healthy children, adolescents and young adults (mean age (sd): 14.2 (3.9) years) participated. Range of joint motion (ROM), muscle strength, anthropometrics sport activities and bone density were measured.</p> <p>Results</p> <p>A prevalence of 12% of ITW was found. Nine percent had ITW and severely restricted ROM of the ankle joint. Children with ITW had three times higher chance of severe ROM restriction of the ankle joint. Participants with ITW and stiff ankle joints had a decreased ROM in other joints, whereas bone density and muscle strength were comparable.</p> <p>Conclusion</p> <p>ITW and a decrease in ankle joint ROM might be due to local stiffness. Differential etiological diagnosis should be considered.</p

Growth characteristics in individuals with osteogenesis imperfecta in North America: results from a multicenter study.

PurposeOsteogenesis imperfecta (OI) predisposes people to recurrent fractures, bone deformities, and short stature. There is a lack of large-scale systematic studies that have investigated growth parameters in OI.MethodsUsing data from the Linked Clinical Research Centers, we compared height, growth velocity, weight, and body mass index (BMI) in 552 individuals with OI. Height, weight, and BMI were plotted on Centers for Disease Control and Prevention normative curves.ResultsIn children, the median z-scores for height in OI types I, III, and IV were -0.66, -6.91, and -2.79, respectively. Growth velocity was diminished in OI types III and IV. The median z-score for weight in children with OI type III was -4.55. The median z-scores for BMI in children with OI types I, III, and IV were 0.10, 0.91, and 0.67, respectively. Generalized linear model analyses demonstrated that the height z-score was positively correlated with the severity of the OI subtype (P &lt; 0.001), age, bisphosphonate use, and rodding (P &lt; 0.05).ConclusionFrom the largest cohort of individuals with OI, we provide median values for height, weight, and BMI z-scores that can aid the evaluation of overall growth in the clinic setting. This study is an important first step in the generation of OI-specific growth curves

Humans and Insects Decide in Similar Ways

Behavioral ecologists assume that animals use a motivational mechanism for decisions such as action selection and time allocation, allowing the maximization of their fitness. They consider both the proximate and ultimate causes of behavior in order to understand this type of decision-making in animals. Experimental psychologists and neuroeconomists also study how agents make decisions but they consider the proximate causes of the behavior. In the case of patch-leaving, motivation-based decision-making remains simple speculation. In contrast to other animals, human beings can assess and evaluate their own motivation by an introspection process. It is then possible to study the declared motivation of humans during decision-making and discuss the mechanism used as well as its evolutionary significance. In this study, we combine both the proximate and ultimate causes of behavior for a better understanding of the human decision-making process. We show for the first time ever that human subjects use a motivational mechanism similar to small insects such as parasitoids [1] and bumblebees [2] to decide when to leave a patch. This result is relevant for behavioral ecologists as it supports the biological realism of this mechanism. Humans seem to use a motivational mechanism of decision making known to be adaptive to a heterogeneously distributed resource. As hypothesized by Hutchinson et al. [3] and Wilke and Todd [4], our results are consistent with the evolutionary shaping of decision making because hominoids were hunters and gatherers on food patches for more than two million years. We discuss the plausibility of a neural basis for the motivation mechanism highlighted here, bridging the gap between behavioral ecology and neuroeconomy. Thus, both the motivational mechanism observed here and the neuroeconomy findings are most likely adaptations that were selected for during ancestral times

Herpes Simplex Virus Type 1 Infection Facilitates Invasion of Staphylococcus aureus into the Nasal Mucosa and Nasal Polyp Tissue

Background: Staphylococcus aureus (S. aureus) plays an important role in the pathogenesis of severe chronic airway disease, such as nasal polyps. However the mechanisms underlying the initiation of damage and/or invasion of the nasal mucosa by S. aureus are not clearly understood. The aim of this study was to investigate the interaction between S. aureus and herpes simplex virus type 1 (HSV1) in the invasion of the nasal mucosa and nasal polyp tissue. Methodology/Principal Findings: Inferior turbinate and nasal polyp samples were cultured and infected with either HSV1 alone, S. aureus alone or a combination of both. Both in turbinate mucosa and nasal polyp tissue, HSV1, with or without S. aureus incubation, led to focal infection of outer epithelial cells within 48 h, and loss or damage of the epithelium and invasion of HSV1 into the lamina propria within 72 h. After pre-infection with HSV1 for 24 h or 48 h, S. aureus was able to pass the basement membrane and invade the mucosa. Epithelial damage scores were significantly higher for HSV1 and S. aureus co-infected explants compared with control explants or S. aureus only-infected explants, and significantly correlated with HSV1-invasion scores. The epithelial damage scores of nasal polyp tissues were significantly higher than those of inferior turbinate tissues upon HSV1 infection. Consequently, invasion scores of HSV1 of nasal polyp tissues were significantly higher than those of inferior turbinate mucosa in the HSV1 and co-infection groups, and invasion scores of S. aureus of nasal polyp tissues were significantly higher than those of inferior turbinate tissues in the co-infection group. Conclusions/Significance: HSV1 may lead to a significant damage of the nasal epithelium and consequently may facilitate invasion of S. aureus into the nasal mucosa. Nasal polyp tissue is more susceptible to the invasion of HSV1 and epithelial damage by HSV1 compared with inferior turbinate mucosa

Cells of the human intestinal tract mapped across space and time

Acknowledgements We acknowledge support from the Wellcome Sanger Cytometry Core Facility, Cellular Genetics Informatics team, Cellular Generation and Phenotyping (CGaP) and Core DNA Pipelines. This work was financially supported by the Wellcome Trust (W1T20694, S.A.T.; 203151/Z/16/Z, R. A. Barker.); the European Research Council (646794, ThDefine, S.A.T.); an MRC New Investigator Research Grant (MR/T001917/1, M.Z.); and a project grant from the Great Ormond Street Hospital Children’s Charity, Sparks (V4519, M.Z.). The human embryonic and fetal material was provided by the Joint MRC/Wellcome (MR/R006237/1) Human Developmental Biology Resource (https://www.hdbr.org/). K.R.J. holds a Non-Stipendiary Junior Research Fellowship from Christ’s College, University of Cambridge. M.R.C. is supported by a Medical Research Council Human Cell Atlas Research Grant (MR/S035842/1) and a Wellcome Trust Investigator Award (220268/Z/20/Z). H.W.K. is funded by a Sir Henry Wellcome Fellowship (213555/Z/18/Z). A.F. is funded by a Wellcome PhD Studentship (102163/B/13/Z). K.T.M. is funded by an award from the Chan Zuckerberg Initiative. H.H.U. is supported by the Oxford Biomedical Research Centre (BRC) and the The Leona M. and Harry B. Helmsley Charitable Trust. We thank A. Chakravarti and S. Chatterjee for their contribution to the analysis of the enteric nervous system. We also thank R. Lindeboom and C. Talavera-Lopez for support with epithelium and Visium analysis, respectively; C. Tudor, T. Li and O. Tarkowska for image processing and infrastructure support; A. Wilbrey-Clark and T. Porter for support with Visium library preparation; A. Ross and J. Park for access to and handling of fetal tissue; A. Hunter for assistance in protocol development; D. Fitzpatrick for discussion on developmental intestinal disorders; and J. Eliasova for the graphical images. We thank the tissue donors and their families, and the Cambridge Biorepository for Translational Medicine and Human Developmental Biology Resource, for access to human tissue. This publication is part of the Human Cell Atlas: https://www.humancellatlas.org/publications.Peer reviewedPublisher PD