7 results on '"Daniel Schmitt"'
Search Results
2. Gaze-behaviors of runners in a natural, urban running environment.
- Author
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Mark M Cullen, Daniel Schmitt, Michael C Granatosky, Christine E Wall, Michael Platt, and Roxanne Larsen
- Subjects
Medicine ,Science - Abstract
Gaze-tracking techniques have advanced our understanding of visual attention and decision making during walking and athletic events, but little is known about how vision influences behavior during running over common, natural obstacles. This study tested hypotheses about whether runners regularly collect visual information and pre-plan obstacle clearance (feedforward control), make improvisational adjustments (online control), or some combination of both. In this study, the gaze profiles of 5 male and 5 female runners, fitted with a telemetric gaze-tracking device, were used to identify the frequency of fixations on an obstacle during a run. Overall, participants fixated on the obstacle 2.4 times during the run, with the last fixation occurring on average between 40% and 80% of the run, suggesting runners potentially shifted from a feedforward planning strategy to an online control strategy during the late portions of the running trial. A negative association was observed between runner velocity and average number of fixations. Consistent with previous studies on visual strategies used during walking, our results indicate that visual attentiveness is part of an important feedforward strategy for runners allowing them to safely approach an obstacle. Thus, visual obstacle attention is a key factor in the navigation of complex, natural landscapes while running.
- Published
- 2020
- Full Text
- View/download PDF
3. Discovery of PF-06928215 as a high affinity inhibitor of cGAS enabled by a novel fluorescence polarization assay.
- Author
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Justin Hall, Amy Brault, Fabien Vincent, Shawn Weng, Hong Wang, Darren Dumlao, Ann Aulabaugh, Dikran Aivazian, Dana Castro, Ming Chen, Jeffrey Culp, Ken Dower, Joseph Gardner, Steven Hawrylik, Douglas Golenbock, David Hepworth, Mark Horn, Lyn Jones, Peter Jones, Eicke Latz, Jing Li, Lih-Ling Lin, Wen Lin, David Lin, Frank Lovering, Nootaree Niljanskul, Ryan Nistler, Betsy Pierce, Olga Plotnikova, Daniel Schmitt, Suman Shanker, James Smith, William Snyder, Timothy Subashi, John Trujillo, Edyta Tyminski, Guoxing Wang, Jimson Wong, Bruce Lefker, Leslie Dakin, and Karen Leach
- Subjects
Medicine ,Science - Abstract
Cyclic GMP-AMP synthase (cGAS) initiates the innate immune system in response to cytosolic dsDNA. After binding and activation from dsDNA, cGAS uses ATP and GTP to synthesize 2', 3' -cGAMP (cGAMP), a cyclic dinucleotide second messenger with mixed 2'-5' and 3'-5' phosphodiester bonds. Inappropriate stimulation of cGAS has been implicated in autoimmune disease such as systemic lupus erythematosus, thus inhibition of cGAS may be of therapeutic benefit in some diseases; however, the size and polarity of the cGAS active site makes it a challenging target for the development of conventional substrate-competitive inhibitors. We report here the development of a high affinity (KD = 200 nM) inhibitor from a low affinity fragment hit with supporting biochemical and structural data showing these molecules bind to the cGAS active site. We also report a new high throughput cGAS fluorescence polarization (FP)-based assay to enable the rapid identification and optimization of cGAS inhibitors. This FP assay uses Cy5-labelled cGAMP in combination with a novel high affinity monoclonal antibody that specifically recognizes cGAMP with no cross reactivity to cAMP, cGMP, ATP, or GTP. Given its role in the innate immune response, cGAS is a promising therapeutic target for autoinflammatory disease. Our results demonstrate its druggability, provide a high affinity tool compound, and establish a high throughput assay for the identification of next generation cGAS inhibitors.
- Published
- 2017
- Full Text
- View/download PDF
4. A new approach to standardize multicenter studies: mobile lab technology for the German Environmental Specimen Bank.
- Author
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Dominik Lermen, Daniel Schmitt, Martina Bartel-Steinbach, Christa Schröter-Kermani, Marike Kolossa-Gehring, Hagen von Briesen, and Heiko Zimmermann
- Subjects
Medicine ,Science - Abstract
Technical progress has simplified tasks in lab diagnosis and improved quality of test results. Errors occurring during the pre-analytical phase have more negative impact on the quality of test results than errors encountered during the total analytical process. Different infrastructures of sampling sites can highly influence the quality of samples and therewith of analytical results. Annually the German Environmental Specimen Bank (ESB) collects, characterizes, and stores blood, plasma, and urine samples of 120-150 volunteers each on four different sampling sites in Germany. Overarching goal is to investigate the exposure to environmental pollutants of non-occupational exposed young adults combining human biomonitoring with questionnaire data. We investigated the requirements of the study and the possibility to realize a highly standardized sampling procedure on a mobile platform in order to increase the required quality of the pre-analytical phase. The results lead to the development of a mobile epidemiologic laboratory (epiLab) in the project "Labor der Zukunft" (future's lab technology). This laboratory includes a 14.7 m(2) reception area to record medical history and exposure-relevant behavior, a 21.1 m(2) examination room to record dental fillings and for blood withdrawal, a 15.5 m(2) biological safety level 2 laboratory to process and analyze samples on site including a 2.8 m(2) personnel lock and a 3.6 m2 cryofacility to immediately freeze samples. Frozen samples can be transferred to their final destination within the vehicle without breaking the cold chain. To our knowledge, we herewith describe for the first time the implementation of a biological safety laboratory (BSL) 2 lab and an epidemiologic unit on a single mobile platform. Since 2013 we have been collecting up to 15.000 individual human samples annually under highly standardized conditions using the mobile laboratory. Characterized and free of alterations they are kept ready for retrospective analyses in their final archive, the German ESB.
- Published
- 2014
- Full Text
- View/download PDF
5. Whole body mechanics of stealthy walking in cats.
- Author
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Kristin L Bishop, Anita K Pai, and Daniel Schmitt
- Subjects
Medicine ,Science - Abstract
The metabolic cost associated with locomotion represents a significant part of an animal's metabolic energy budget. Therefore understanding the ways in which animals manage the energy required for locomotion by controlling muscular effort is critical to understanding limb design and the evolution of locomotor behavior. The assumption that energetic economy is the most important target of natural selection underlies many analyses of steady animal locomotion, leading to the prediction that animals will choose gaits and postures that maximize energetic efficiency. Many quadrupedal animals, particularly those that specialize in long distance steady locomotion, do in fact reduce the muscular contribution required for walking by adopting pendulum-like center of mass movements that facilitate exchange between kinetic energy (KE) and potential energy (PE). However, animals that are not specialized for long distance steady locomotion may face a more complex set of requirements, some of which may conflict with the efficient exchange of mechanical energy. For example, the "stealthy" walking style of cats may demand slow movements performed with the center of mass close to the ground. Force plate and video data show that domestic cats (Felis catus, Linnaeus, 1758) have lower mechanical energy recovery than mammals specialized for distance. A strong negative correlation was found between mechanical energy recovery and diagonality in the footfalls and there was also a negative correlation between limb compression and diagonality of footfalls such that more crouched postures tended to have greater diagonality. These data show a previously unrecognized mechanical relationship in which crouched postures are associated with changes in footfall pattern which are in turn related to reduced mechanical energy recovery. Low energy recovery was not associated with decreased vertical oscillations of the center of mass as theoretically predicted, but rather with posture and footfall pattern on the phase relationship between potential and kinetic energy. An important implication of these results is the possibility of a tradeoff between stealthy walking and economy of locomotion. This potential tradeoff highlights the complex and conflicting pressures that may govern the locomotor choices that animals make.
- Published
- 2008
- Full Text
- View/download PDF
6. Gaze-behaviors of runners in a natural, urban running environment
- Author
-
Christine E. Wall, Michael C. Granatosky, Mark M. Cullen, Roxanne J. Larsen, Daniel Schmitt, and Michael L. Platt
- Subjects
Male ,genetic structures ,Physiology ,Vision ,Visual System ,Sensory Physiology ,Social Sciences ,Negative association ,Walking ,Running ,Ocular physiology ,0302 clinical medicine ,Medicine and Health Sciences ,Psychology ,Attention ,Multidisciplinary ,Applied Mathematics ,Simulation and Modeling ,05 social sciences ,Sensory Systems ,Obstacle ,Physical Sciences ,Medicine ,Visual attentiveness ,Sensory Perception ,Female ,Anatomy ,Algorithms ,Cognitive psychology ,Research Article ,Adult ,Science ,Fixation, Ocular ,Research and Analysis Methods ,050105 experimental psychology ,03 medical and health sciences ,Ocular System ,Visual attention ,Humans ,0501 psychology and cognitive sciences ,Biological Locomotion ,Feed forward ,Cognitive Psychology ,Biology and Life Sciences ,Fixation (psychology) ,Gaze ,Cognitive Science ,Eyes ,human activities ,Head ,030217 neurology & neurosurgery ,Mathematics ,Neuroscience - Abstract
Gaze-tracking techniques have advanced our understanding of visual attention and decision making during walking and athletic events, but little is known about how vision influences behavior during running over common, natural obstacles. This study tested hypotheses about whether runners regularly collect visual information and pre-plan obstacle clearance (feedforward control), make improvisational adjustments (online control), or some combination of both. In this study, the gaze profiles of 5 male and 5 female runners, fitted with a telemetric gaze-tracking device, were used to identify the frequency of fixations on an obstacle during a run. Overall, participants fixated on the obstacle 2.4 times during the run, with the last fixation occurring on average between 40% and 80% of the run, suggesting runners potentially shifted from a feedforward planning strategy to an online control strategy during the late portions of the running trial. A negative association was observed between runner velocity and average number of fixations. Consistent with previous studies on visual strategies used during walking, our results indicate that visual attentiveness is part of an important feedforward strategy for runners allowing them to safely approach an obstacle. Thus, visual obstacle attention is a key factor in the navigation of complex, natural landscapes while running.
- Published
- 2020
7. Whole body mechanics of stealthy walking in cats
- Author
-
Anita K. Pai, Daniel Schmitt, and Kristin L. Bishop
- Subjects
0106 biological sciences ,Physiology ,lcsh:Medicine ,Walking ,Biology ,Mechanics ,010603 evolutionary biology ,01 natural sciences ,03 medical and health sciences ,Quadrupedalism ,Control theory ,Animals ,Set (psychology) ,lcsh:Science ,Gait ,Mechanical energy ,030304 developmental biology ,0303 health sciences ,Evolutionary Biology ,Multidisciplinary ,Evolutionary Biology/Animal Behavior ,Animal locomotion ,lcsh:R ,Potential energy ,Metabolic cost ,Cats ,lcsh:Q ,Whole body ,Energy Metabolism ,Locomotion ,Research Article - Abstract
The metabolic cost associated with locomotion represents a significant part of an animal's metabolic energy budget. Therefore understanding the ways in which animals manage the energy required for locomotion by controlling muscular effort is critical to understanding limb design and the evolution of locomotor behavior. The assumption that energetic economy is the most important target of natural selection underlies many analyses of steady animal locomotion, leading to the prediction that animals will choose gaits and postures that maximize energetic efficiency. Many quadrupedal animals, particularly those that specialize in long distance steady locomotion, do in fact reduce the muscular contribution required for walking by adopting pendulum-like center of mass movements that facilitate exchange between kinetic energy (KE) and potential energy (PE) [1]–[4]. However, animals that are not specialized for long distance steady locomotion may face a more complex set of requirements, some of which may conflict with the efficient exchange of mechanical energy. For example, the “stealthy” walking style of cats may demand slow movements performed with the center of mass close to the ground. Force plate and video data show that domestic cats (Felis catus, Linnaeus, 1758) have lower mechanical energy recovery than mammals specialized for distance. A strong negative correlation was found between mechanical energy recovery and diagonality in the footfalls and there was also a negative correlation between limb compression and diagonality of footfalls such that more crouched postures tended to have greater diagonality. These data show a previously unrecognized mechanical relationship in which crouched postures are associated with changes in footfall pattern which are in turn related to reduced mechanical energy recovery. Low energy recovery was not associated with decreased vertical oscillations of the center of mass as theoretically predicted, but rather with posture and footfall pattern on the phase relationship between potential and kinetic energy. An important implication of these results is the possibility of a tradeoff between stealthy walking and economy of locomotion. This potential tradeoff highlights the complex and conflicting pressures that may govern the locomotor choices that animals make.
- Published
- 2008
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