3,131 research outputs found
Congenital Toxoplasmosis: In Vivo Impact of Toxoplasma gondii Infection on Myogenesis and Neurogenesis
Congenital toxoplasmosis (TC) from Toxoplasma gondii positive mother to child transmission results in fetal death, abortion, or infantile neurologic and neurocognitive deficits as well as chorioretinitis. This study aims to analyze the morphological changes in brain and skeletal muscle cells of Swiss mouse embryos during experimental congenital toxoplasmosis. Swiss mice, before mating, were gavage inoculation infected with approximately 25 or 50 cysts of ME‐49 strain T. gondii. Eighteen day postcoitus maternal and embryonic muscle and brain samples were collected and processed for histopathological analysis. The muscle tissue from embryos of infected mothers, in comparison with healthy muscle myofibers, exhibited discontinuous and shorter myofibrils, more interfibrillar space and immature cells with fewer stained and poorly defined striated profiles. These in vivo findings might be related to an adhesion protein decrease, observed in vitro, where myogenesis was completely affected during Toxoplasma infection. The neurogenesis was severely affected with irregularly arranged cells, reduced cell density, and a significant intercellular space increase. The brain tissue presented ischemia, cell death, necrosis, and thrombi, increasing according to the degree of the acute infection, which compromised the neurogenesis, thereby justifying brain size decrease in these embryos
Holographic enhanced remote sensing system
The Holographic Enhanced Remote Sensing System (HERSS) consists of three primary subsystems: (1) an Image Acquisition System (IAS); (2) a Digital Image Processing System (DIPS); and (3) a Holographic Generation System (HGS) which multiply exposes a thermoplastic recording medium with sequential 2-D depth slices that are displayed on a Spatial Light Modulator (SLM). Full-parallax holograms were successfully generated by superimposing SLM images onto the thermoplastic and photopolymer. An improved HGS configuration utilizes the phase conjugate recording configuration, the 3-SLM-stacking technique, and the photopolymer. The holographic volume size is currently limited to the physical size of the SLM. A larger-format SLM is necessary to meet the desired 6 inch holographic volume. A photopolymer with an increased photospeed is required to ultimately meet a display update rate of less than 30 seconds. It is projected that the latter two technology developments will occur in the near future. While the IAS and DIPS subsystems were unable to meet NASA goals, an alternative technology is now available to perform the IAS/DIPS functions. Specifically, a laser range scanner can be utilized to build the HGS numerical database of the objects at the remote work site
Understanding the tsunami with a simple model
In this paper, we use the approximation of shallow water waves (Margaritondo
G 2005 Eur. J. Phys. 26 401) to understand the behaviour of a tsunami in a
variable depth. We deduce the shallow water wave equation and the continuity
equation that must be satisfied when a wave encounters a discontinuity in the
sea depth. A short explanation about how the tsunami hit the west coast of
India is given based on the refraction phenomenon. Our procedure also includes
a simple numerical calculation suitable for undergraduate students in physics
and engineering
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Use and cost of disease-modifying therapies by Sonya Slifka Study participants: has anything really changed since 2000 and 2009?
Background:Disease-modifying therapies benefit individuals with relapsing forms of multiple sclerosis, but their utility remains unclear for those without relapses. Objective:To determine disease-modifying therapy use and costs in 2009, compare use in 2009 and 2000, and examine compliance with evidence-based guidelines. Methods:We determined the extent and characteristics of disease-modifying therapy use by participants in the Sonya Slifka Longitudinal Multiple Sclerosis Study (Slifka) in 2000 (n=2156) and 2009 (n=2361) and estimated out-of-pocket and total (payer) costs for 2009. Two multivariable logistic regressions predicted disease-modifying therapy use. Results:Disease-modifying therapy use increased from 55.3% in 2000 to 61.5% in 2009. In 2009, disease-modifying therapy use was reported by 76.5% of participants with relapsing-remitting multiple sclerosis, 73.2% with progressive-relapsing multiple sclerosis, 62.5% with secondary progressive multiple sclerosis, and 41.8% with primary progressive multiple sclerosis. Use was significantly associated with relapsing-remitting multiple sclerosis, shorter duration of illness, one to two relapses per year, non-ambulatory symptoms, using a cane, younger age, higher family income, and having health insurance. Average annual costs in 2009 were US16,302-18,928 for payers. Conclusion:Use rates were highest for individuals with relapsing-remitting multiple sclerosis, but substantial for those with progressive courses although clinical trials have not demonstrated significant benefits for them
Monitoring and cross-checking automation : Do four eyes see more than two?
Dieser Beitrag ist mit Zustimmung des Rechteinhabers aufgrund einer (DFG geförderten) Allianz- bzw. Nationallizenz frei zugänglich.This publication is with permission of the rights owner freely accessible due to an Alliance licence and a national licence (funded by the DFG, German Research Foundation) respectively.The present study addresses effects of human redundancy on automation monitoring and cross-checking. Thirty-six participants performed a multi-task, consisting of three subtasks that mimic basic work demands of operators in a control room of a chemical plant. One of the tasks was to monitor and cross-check a highly reliable and safety-critical automated process. Participants were randomly assigned to two groups: (1) Non-redundant: participants worked on all tasks alone as the only responsible operator. (2) Redundant: participants were informed that a second crewmate would work in parallel on the automation monitoring task and that they both were responsible for ensuring safe operation of the automation. Results provide evidence for social loafing effects in automation cross-checking. Participants working redundantly with another crewmate were found to cross-check the automation significantly less than participants, who were working alone. Even if the combined team performance of the participants working in the redundant condition was considered, the number of cross-checks did not significantly differ from the performance in the non-redundant condition. This result suggests that human redundancy can induce social loafing effects which fully compensate a possible reliability gain intended to be achieved by this measure. It challenges the often stated assumption that 'four eyes see more than two' and shows that human redundancy does not necessarily lead to enhanced safety in automation monitoring
Active mechanics reveal molecular-scale force kinetics in living oocytes
Active diffusion of intracellular components is emerging as an important
process in cell biology. This process is mediated by complex assemblies of
molecular motors and cytoskeletal filaments that drive force generation in the
cytoplasm and facilitate enhanced motion. The kinetics of molecular motors have
been precisely characterized in-vitro by single molecule approaches, however,
their in-vivo behavior remains elusive. Here, we study the active diffusion of
vesicles in mouse oocytes, where this process plays a key role in nuclear
positioning during development, and combine an experimental and theoretical
framework to extract molecular-scale force kinetics (force, power-stroke, and
velocity) of the in-vivo active process. Assuming a single dominant process, we
find that the nonequilibrium activity induces rapid kicks of duration 300 s resulting in an average force of 0.4 pN on vesicles
in in-vivo oocytes, remarkably similar to the kinetics of in-vitro myosin-V.
Our results reveal that measuring in-vivo active fluctuations allows extraction
of the molecular-scale activity in agreement with single-molecule studies and
demonstrates a mesoscopic framework to access force kinetics.Comment: 20 pages, 4 figures, see ancillary files for Supplementary Materials,
* equally contributing author
Prediction of ‘Nules Clementine’ mandarin susceptibility to rind breakdown disorder using Vis/NIR spectroscopy
The use of diffuse reflectance visible and near infrared (Vis/NIR) spectroscopy was explored as a non-destructive technique to predict ‘Nules Clementine’ mandarin fruit susceptibility to rind breakdown (RBD) disorder by detecting rind physico-chemical properties of 80 intact fruit harvested from different canopy positions. Vis/NIR spectra were obtained using a LabSpec® spectrophotometer. Reference physico-chemical data of the fruit were obtained after 8 weeks of storage at 8 °C using conventional methods and included RBD, hue angle, colour index, mass loss, rind dry matter, as well as carbohydrates (sucrose, glucose, fructose, total carbohydrates), and total phenolic acid concentrations. Principal component analysis (PCA) was applied to analyse spectral data to identify clusters in the PCA score plots and outliers. Partial least squares (PLS) regression was applied to spectral data after PCA to develop prediction models for each quality attribute. The spectra were subjected to a test set validation by dividing the data into calibration (n = 48) and test validation (n = 32) sets. An extra set of 40 fruit harvested from a different part of the orchard was used for external validation. PLS-discriminant analysis (PLS-DA) models were developed to sort fruit based on canopy position and RBD susceptibility. Fruit position within the canopy had a significant influence on rind biochemical properties. Outside fruit had higher rind carbohydrates, phenolic acids and dry matter content and lower RBD index than inside fruit. The data distribution in the PCA and PLS-DA models displayed four clusters that could easily be identified. These clusters allowed distinction between fruit from different preharvest treatments. NIR calibration and validation results demonstrated that colour index, dry matter, total carbohydrates and mass loss were predicted with significant accuracy, with residual predictive deviation (RPD) for prediction of 3.83, 3.58, 3.15 and 2.61, respectively. The good correlation between spectral information and carbohydrate content demonstrated the potential of Vis/NIR as a non-destructive tool to predict fruit susceptibility to RBD
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