38,195,485 research outputs found
A Method to Identify and Analyze Biological Programs through Automated Reasoning.
Predictive biology is elusive because rigorous, data-constrained, mechanistic models of complex biological systems are difficult to derive and validate. Current approaches tend to construct and examine static interaction network models, which are descriptively rich but often lack explanatory and predictive power, or dynamic models that can be simulated to reproduce known behavior. However, in such approaches implicit assumptions are introduced as typically only one mechanism is considered, and exhaustively investigating all scenarios is impractical using simulation. To address these limitations, we present a methodology based on automated formal reasoning, which permits the synthesis and analysis of the complete set of logical models consistent with experimental observations. We test hypotheses against all candidate models, and remove the need for simulation by characterizing and simultaneously analyzing all mechanistic explanations of observed behavior. Our methodology transforms knowledge of complex biological processes from sets of possible interactions and experimental observations to precise, predictive biological programs governing cell function
Dynamic spin-lattice coupling and nematic fluctuations in NaFeAs
We use inelastic neutron scattering to study acoustic phonons and spin
excitations in single crystals of NaFeAs, a parent compound of iron pnictide
superconductors. NaFeAs exhibits a tetragonal-to-orthorhombic structural
transition at K and a collinear antiferromagnetic (AF) order at
K. While longitudinal and out-of-plane transverse acoustic
phonons behave as expected, the in-plane transverse acoustic phonons reveal
considerable softening on cooling to , and then harden on approaching
before saturating below . In addition, we find that spin-spin
correlation lengths of low-energy magnetic excitations within the FeAs layer
and along the -axis increase dramatically below , and show weak anomaly
across . These results suggest that the electronic nematic phase present
in the paramagnetic tetragonal phase is closely associated with dynamic
spin-lattice coupling, possibly arising from the one-phonon-two-magnon
mechanism
Hyperglycemia Induction in HepG2 Cell Line
Background: Hyperglycemia is one of the important featurs of diabetes. In cell culture studies different methods are used to mimic the hyperglycemia condition. In this study we investigate response of human liver cancer cell line (HepG2) to high insulin, high glucose, and high insulin/ high glucose medium exposure.Methods: HepG2 cells were settled in DMEM+0.1% FBS or DMEM free-serum medium with high concentrations of d-glucose (30 mm) and/or insulin (1Ī¼M) for 24h after an overnight starving in serum- free medium. The level of hyperglycemia was estimated in the supernatants via GOD-POD method.Results: Serum-free madium with high insulin/ high glucose consentration made the higher level of hypreglycemia in HepG2 cells.Conclusions: Our study interduced high insulin/ high glucose treatment as the best way to induction hyperglycemia.
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