Background: Precise knowledge of variability in colonic anatomy is of great importance for numerical modeling studies of the abdomen. This knowledge would allow the creation of personalized models for the gastrointestinal tract used for surgical simulations or in studies of virtual trauma.
Materials And Methods: To determine the colonic configuration in the general population and define its variability by gender, age, and corpulence, the layout of the colon was determined via the following reference points: ileocecal junction, left and right colonic flexures, and colosigmoid junction (CSJ). Three-dimensional coordinates for each point were recorded on scanned sections of 100 healthy adults to examine the colonic layout under physiological conditions. Coordinates were repositioned in a new anatomical reference for comparison. The average points' coordinates, standard deviations, and distances between them were compared for each group.
Results: The right colonic flexure was the most variable point. The CSJ was the least variable. Gender affected mainly the height of the colonic flexures and the length of its segments. Age affected the length of the transverse mesocolon root. Corpulence affected both the position of the ileocecal and CSJs and the length of the right colon. Differences in size and perivisceral fat distribution between groups explained these differences. Three-dimensional anatomical models of the colon were defined for each group by statistical equations.
Conclusion: These equations, combined with data concerning the actual lengths of the colonic segments, enable reconstruction of different anatomical models of the colon that are representative according to gender, age, and corpulence.
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http://dx.doi.org/10.1016/j.jss.2012.03.054 | DOI Listing |
Phys Rev Lett
December 2024
Department of Physics and Astronomy, University of Rochester, Rochester, New York 14627, USA.
We investigate the thermoelectric response of an Abrikosov vortex in type-II superconductors in the deep quantum limit. We consider two thermoelectric geometries, a type-II superconductor-insulator-normal-metal (S-I-N) junction and a local scanning tunneling microscope (STM)-tip normal metal probe over the superconductor. We exploit the strong breaking of particle-hole symmetry in vortex-bound states at subgap energies within the superconducting vortex to realize a giant thermoelectric response in the presence of fluxons.
View Article and Find Full Text PDFPhys Rev Lett
December 2024
School of Physics and Astronomy, Institute of Natural Sciences and MOE-LSC, Shanghai Jiao Tong University, Shanghai 200240, China.
Chemically driven micromotors exhibit a pronounced affinity for nearby surfaces, yet the quantification of this motor-wall interaction strength remains unexplored in experiments. Here, we apply an external force to a self-electrophoretic micromotor which slides along a wall and measures the force necessary to disengage the motor from the wall. Our experiments unveil that the required disengaging force increases with the strength of chemical driving, often surpassing both the motor's effective gravity and its propulsive thrust.
View Article and Find Full Text PDFPhys Rev Lett
December 2024
Instituto de Biocomputación y Física de Sistemas Complejos (BIFI), 50018 Zaragoza, Spain.
Rejuvenation and memory, long considered the distinguishing features of spin glasses, have recently been proven to result from the growth of multiple length scales. This insight, enabled by simulations on the Janus II supercomputer, has opened the door to a quantitative analysis. We combine numerical simulations with comparable experiments to introduce two coefficients that quantify memory.
View Article and Find Full Text PDFPhys Rev Lett
December 2024
Initiative for the Theoretical Sciences and CUNY-Princeton Center for the Physics of Biological Function, The Graduate Center, CUNY, New York, New York 10016, USA.
The random-energy model (REM), a solvable spin-glass model, has impacted an incredibly diverse set of problems, from protein folding to combinatorial optimization, to many-body localization. Here, we explore a new connection to secret sharing. We derive an analytic expression for the mutual information between any two disjoint thermodynamic subsystems of the REM.
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