6,585 research outputs found
Long-term in vitro 3D hydrogel co-culture model of inflammatory bowel disease
The in vitro study of the pathogenesis of inflammatory bowel disease (IBD) requires a cell model which closely reflects the characteristics of the in vivo intestinal epithelium. This study aimed to investigate the application of L-pNIPAM hydrogel as a scaffold to develop a long-term 3D co-culture model of Caco-2 and HT29-MTX cells under conditions analogous to inflammation, to determine its potential use in studying IBD. Monocultures and co-cultures were layered on L-pNIPAM hydrogel scaffolds and maintained under dynamic culture conditions for up to 12 weeks. Treatments with IL-1ÎČ, TNFα, and hypoxia for 1 week were used to create an inflammatory environment. Following prolonged culture, the metabolic activity of Caco-2 monoculture and 90% Caco-2/10% HT29-MTX co-cultures on L-pNIPAM hydrogels were increased, and finger-like structures, similar in appearance to villi were observed. Following treatment with IL-1ÎČ, TNFα and hypoxia, ALP and ZO-1 were decreased, MUC2 increased, and MUC5AC remained unchanged. ADAMTS1 was increased in response to hypoxia. Caspase 3 expression was increased in response to TNFα and hypoxic conditions. In conclusion, L-pNIPAM hydrogel supported long-term co-culture within a 3D model. Furthermore, stimulation with factors seen during inflammation recapitulated features seen during IBD
Signs of the rates in the Lindblad master equations can always be arbitrarily determined
Determining the Markovianity and non-Markovianity of a quantum process is a
critical problem in the theory of open quantum systems, as their behaviors
differ significantly in terms of complexity. It is well recognized that a
quantum process is Markovian if and only if the quantum master equation can be
written in the standard Lindblad form with all rates nonnegative for all time.
However, here we present a striking result that \textit{any} finite-dimensional
open quantum system dynamics can be described by a quantum master equation in
the Lindblad form with all rates nonnegative for all time. In fact, it can be
shown that one can arbitrarily decide the sign of the rates in any case at any
time interval. Note that here we take an unconventional approach where the
quantum master equation we construct will in general be state-dependent, which
means that the Hamiltonian, jump operators and rates will all depend on the
current state of the density matrix . Our findings raise serious
questions on the current criterion in determining Markovianity and
non-Markovianity in open quantum system dynamics.Comment: 5 page
Quantum State Driving along Arbitrary Trajectories
Starting with the quantum brachistochrone problem of the infinitesimal form,
we solve the minimal time and corresponding time-dependent Hamiltonian to drive
a pure quantum state with limited resources along arbitrary pre-assigned
trajectories. It is also shown that out of all possible trajectories, with
limited resources, which are physically accessible and which are not. The
solution is then generalized to the mixed quantum state cases, and applied to
trajectories parameterized by single or multiple parameters with discrete or
continuous spectrum. We then compare the solution to that of the
counterdiabatic driving, and show how the Berry phase is directly involved in
both driving processes.Comment: 7 pages, 3 figure
Describing the Wave Function Collapse Process with a State-dependent Hamiltonian
It is well-known that quantum mechanics admits two distinct evolutions: the
unitary evolution, which is deterministic and well described by the
Schr\"{o}dinger equation, and the collapse of the wave function, which is
probablistic, generally non-unitary, and cannot be described by the
Schr\"{o}dinger equation. In this paper, starting with pure states, we show how
the continuous collapse of the wave function can be described by the
Schr\"{o}dinger equation with a stochastic, time-dependent Hamiltonian. We
analytically solve for the Hamiltonian responsible for projective measurements
on an arbitrary -level system and the position measurement on an harmonic
oscillator in the ground state, and propose several experimental schemes to
verify and utilize the conclusions. A critical feature is that the Hamiltonian
must be state-dependent. We then discuss how the above formalism can also be
applied to describe the collapse of the wave function of mixed quantum states.
The formalism we proposed may unify the two distinct evolutions in quantum
mechanics.Comment: 12 pages, 1 figur
Quantifying goodness of story narratives
In the present study an additional measure of story narrative performance, story completeness, is evaluated. The completeness measure involves a tally of the critical story components mentioned by a storyteller. It was hypothesized that by combining organizational (story grammar) and completeness measures, story âgoodnessâ could be quantified. Data from 46 normal adults indicated that this analysis was relatively sensitive in that it classified the story narratives of the group into four distinct categories of story âgoodnessâ. This analysis should prove useful for the study of narrative discourse of brain-injured populations
Quantifying goodness of story narratives
In the present study an additional measure of story narrative performance, story completeness, is evaluated. The completeness measure involves a tally of the critical story components mentioned by a storyteller. It was hypothesized that by combining organizational (story grammar) and completeness measures, story âgoodnessâ could be quantified. Data from 46 normal adults indicated that this analysis was relatively sensitive in that it classified the story narratives of the group into four distinct categories of story âgoodnessâ. This analysis should prove useful for the study of narrative discourse of brain-injured populations
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