461 research outputs found
Efficient and practical synthesis of N-acetyl enamides from ketoximes by unique iron catalytic system
A new procedure for the iron-catalyzed synthesis of enamides from ketoximes was developed, and its mechanism was proposed. A unique reduction system, with the concerted use of KI and Na2S2O4, was involved. The reaction exhibited a wide substrate scope and gave good yields in a short reaction time. The procedure is operationally simple and also applicable for the large-scale synthesis
Role of Topology in Relaxation of One-Dimensional Stochastic Processes
Stochastic processes are commonly used models to describe dynamics of a wide
variety of nonequilibrium phenomena ranging from electrical transport to
biological motion. The transition matrix describing a stochastic process can be
regarded as a non-Hermitian Hamiltonian. Unlike general non-Hermitian systems,
the conservation of probability imposes additional constraints on the
transition matrix, which can induce unique topological phenomena. Here, we
reveal the role of topology in relaxation phenomena of classical stochastic
processes. Specifically, we define a winding number that is related to topology
of stochastic processes and show that it predicts the existence of a spectral
gap that characterizes the relaxation time. Then, we numerically confirm that
the winding number corresponds to the system-size dependence of the relaxation
time and the characteristic transient behavior. One can experimentally realize
such topological phenomena in magnetotactic bacteria and cell adhesions.Comment: 6+17 pages, 4+15 figure
The epigenetic function of androgen receptor in prostate cancer progression
Androgen and androgen deprivation (castration) therapies, including androgen receptor antagonists, are clinically used to treat patients with prostate cancer. However, most hormone-dependent prostate cancer patients progress into a malignant state with loss of hormone-dependency, known as castration (drug)-resistant prostate cancer (CRPC), after prolong androgen-based treatments. Even in the CRPC state with irreversible malignancy, androgen receptor (AR) expression is detectable. An epigenetic transition to CRPC induced by the action of AR-mediated androgen could be speculated in the patients with prostate cancer. Androgen receptors belongs to the nuclear receptor superfamily with 48 members in humans, and acts as a ligand-dependent transcriptional factor, leading to local chromatin reorganization for ligand-dependent gene regulation. In this review, we discussed the transcriptional/epigenetic regulatory functions of AR, with emphasis on the clinical applications of AR ligands, AR protein co-regulators, and AR RNA coregulator (enhancer RNA), especially in chromatin reorganization, in patients with prostate cancer
Pion PDFs confronted by Fixed-Target Charmonium Production
The pion, as the Goldstone boson of the strong interaction, is the lightest
QCD bound state and responsible for the long-range nucleon-nucleon interaction
inside the nucleus. Our knowledge on the pion partonic structure is limited by
the existing Drell-Yan data which are primarily sensitive to the pion
valence-quark distributions. The recent progress of global analysis of pion's
parton distribution functions (PDFs) utilizing various experimental approaches
are introduced. From comparisons between the pion-induced and
production data with theoretical calculations using the CEM and
NRQCD models, we show how these charmonium production data could provide useful
constraints on the pion PDFs.Comment: 17 pages, 6 figures; invited review. arXiv admin note: text overlap
with arXiv:2006.06947, arXiv:2209.0407
Development of independent dose verification plugin using Eclipse scripting API for brachytherapy
In this study, an independent dose verification plugin (DVP) using the Eclipse Scripting Application Programming Interface (ESAPI) for brachytherapy was developed. The DVP was based on the general 2D formalism reported in AAPM-TG43U1. The coordinate and orientation of each source position were extracted from the translation matrix acquired from the treatment planning system (TPS), and the distance between the source and verification point (r) was calculated. Moreover, the angles subtended by the center-tip and tip-tip of the hypothetical line source with respect to the verification point (θ and β) were calculated. With r, θ, β and the active length of the source acquired from the TPS, the geometry function was calculated. As the TPS calculated the radial dose function, g(r), and 2D anisotropy function, F(r, θ), by interpolating and extrapolating the corresponding table stored in the TPS, the DVP calculated g(r) and F(r, θ) independently from equations fitted with the Monte Carlo data. The relative deviation of the fitted g(r) and F(r, θ) for the GammaMed Plus HDR 192Ir source was 0.5% and 0.9%, respectively. The acceptance range of the relative dose difference was set to ±1.03% based on the relative deviation between the fitted functions and Monte Carlo data, and the linear error propagation law. For 64 verification points from sixteen plans, the mean of absolute values of the relative dose difference was 0.19%. The standard deviation (SD) of the relative dose difference was 0.17%. The DVP maximizes efficiency and minimizes human error for the brachytherapy plan check
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