113 research outputs found
Laser-induced electron localization in H: Mixed quantum-classical dynamics based on the exact time-dependent potential energy surface
We study the exact nuclear time-dependent potential energy surface (TDPES)
for laser-induced electron localization with a view to eventually developing a
mixed quantum-classical dynamics method for strong-field processes. The TDPES
is defined within the framework of the exact factorization [A. Abedi, N. T.
Maitra, and E. K. U. Gross, Phys. Rev. Lett. 105, 123002 (2010)] and contains
the exact effect of the couplings to the electronic subsystem and to any
external fields within a scalar potential. We compare its features with those
of the quasistatic potential energy surfaces (QSPES) often used to analyse
strong-field processes. We show that the gauge-independent component of the
TDPES has a mean-field-like character very close to the density-weighted
average of the QSPESs. Oscillations in this component are smoothened out by the
gauge-dependent component, and both components are needed to yield the correct
force on the nuclei. Once the localization begins to set in, the gradient of
the exact TDPES tracks one QSPES and then switches to the other, similar to the
description provided by surface-hopping between QSPESs. We show that evolving
an ensemble of classical nuclear trajectories on the exact TDPES accurately
reproduces the exact dynamics. This study suggests that the mixed
quantum-classical dynamics scheme based on evolving multiple classical nuclear
trajectories on the exact TDPES will be a novel and useful method to simulate
strong field processes.Comment: 10 pages, 6 figure
Electron Scattering in Time-Dependent Density Functional Theory
It was recently shown [Y. Suzuki, L. Lacombe, K. Watanabe, and N. T. Maitra,
Phys. Rev. Lett. 119, 263401 (2017)] that peak and valley structures in the
exact exchange-correlation potential of time-dependent density functional
theory are crucial for accurately capturing time-resolved dynamics of electron
scattering in a model one-dimensional system. Approximate functionals used
today miss these structures and con- sequently underestimate the scattering
probability. The dynamics can vary significantly depending on the choice of the
initial Kohn-Sham state, and, with a judicious choice, a recently-proposed
non-adiabatic ap- proximation provides extremely accurate dynamics on approach
to the target but this ultimately also fails to capture reflection accurately.
Here we provide more details, using a model of electron-He + as illustration,
in both the inelastic and elastic regimes. In the elastic case, the
time-resolved picture is contrasted with the time-independent picture of
scattering, where the linear response theory of TDDFT can be used to extract
transmission and reflection coefficients. Although the exact functional yields
identical scattering probabil- ities when used in this way as it does in the
time-resolved picture, we show that the currently-available approximate
functionals do not, even when they have the correct asymptotic behavior.Comment: 9 pages, 6 figure
The exact forces on classical nuclei in non-adiabatic charge transfer
The decomposition of electronic and nuclear motion presented in Abedi et al. [Phys. Rev. Lett. 105, 123002 (2010)] yields a time-dependent potential that drives the nuclear motion and fully accounts for the coupling to the electronic subsystem. Here, we show that propagation of an ensemble of independent classical nuclear trajectories on this exact potential yields dynamics that are essentially indistinguishable from the exact quantum dynamics for a model non-adiabatic charge transfer problem. We point out the importance of step and bump features in the exact potential that are critical in obtaining the correct splitting of the quasiclassical nuclear wave packet in space after it passes through an avoided crossing between two Born-Oppenheimer surfaces and analyze their structure. Finally, an analysis of the exact potentials in the context of trajectory surface hopping is presented, including preliminary investigations of velocity-adjustment and the force-induced decoherence effect. (C) 2015 AIP Publishing LLC.open5
Randomised study of adjuvant chemotherapy for completely resected p-stage I–IIIA non-small cell lung cancer
We evaluated the therapeutic usefulness of adjuvant chemotherapy in patients with completely resected non-small cell lung cancer (NSCLC). We also examined the relation between DNA ploidy pattern and the response to chemotherapy. A total of 267 patients with NSCLC (pathologically documented stage I, II, or IIIA) underwent complete resection, and DNA ploidy pattern was analysed. Patients with stage I disease (n=172) were randomly assigned to receive surgery alone (group A) or surgery followed by adjuvant chemotherapy (UFT (oral anti-cancer drug, a combination of Uracil and Tegaful) 400 mg day−1 for 1 year after surgery; group B). Stage II or IIIA disease patients (n=95) were randomly assigned to surgery alone (group C) or surgery followed by chemotherapy (two 28-day courses of cisplatin 80 mg m−2 on day 1 plus vindesine 3 mg m−2 on days 1 and 8, followed by UFT 400 mg day−1 for at least 1 year; group D). Eight-year overall survival rate in patients with stage I disease was 74.2% (95% confidence interval (CI): 64.4–84.0%) in group B and 57.6% (95% CI: 46.4–68.8%) in group A (P=0.045 by log-rank test). In patients with stage II and IIIA disease, no difference was found between groups C and D. Analysis according to DNA ploidy pattern revealed no difference between the groups. Postoperative chemotherapy with UFT was suggested to be useful in patients with completely resected stage I NSCLC. No difference was seen in relation to DNA pattern in any treatment group
MUC1-C Oncoprotein Regulates Glycolysis and Pyruvate Kinase m2 Activity in Cancer Cells
Aerobic glycolysis in cancer cells is regulated by multiple effectors that include Akt and pyruvate kinase M2 (PKM2). Mucin 1 (MUC1) is a heterodimeric glycoprotein that is aberrantly overexpressed by human breast and other carcinomas. Here we show that transformation of rat fibroblasts by the oncogenic MUC1-C subunit is associated with Akt-mediated increases in glucose uptake and lactate production, consistent with the stimulation of glycolysis. The results also demonstrate that the MUC1-C cytoplasmic domain binds directly to PKM2 at the B- and C-domains. Interaction between the MUC1-C cytoplasmic domain Cys-3 and the PKM2 C-domain Cys-474 was found to stimulate PKM2 activity. Conversely, epidermal growth factor receptor (EGFR)-mediated phosphorylation of the MUC1-C cytoplasmic domain on Tyr-46 conferred binding to PKM2 Lys-433 and inhibited PKM2 activity. In human breast cancer cells, silencing MUC1-C was associated with decreases in glucose uptake and lactate production, confirming involvement of MUC1-C in the regulation of glycolysis. In addition, EGFR-mediated phosphorylation of MUC1-C in breast cancer cells was associated with decreases in PKM2 activity. These findings indicate that the MUC1-C subunit regulates glycolysis and that this response is conferred in part by PKM2. Thus, the overexpression of MUC1-C oncoprotein in diverse human carcinomas could be of importance to the Warburg effect of aerobic glycolysis
Head computed tomographic measurement as a predictor of outcome in patients with subdural hematoma with cerebral edema
Expression of matrix metalloproteinase-9 in the neoplastic and interstitial inflammatory infiltrate cells in gastric cancer.
Prognostication and monitoring of mesothelioma using biomarkers:a systematic review
Background: Radiological markers of treatment response and prognostication in malignant pleural mesothelioma have limitations due to the morphology of the disease. Serum or pleural fluid biomarkers that could act as an adjunct to radiological assessment would be of significant value. The aim of this review was to collate and summarise the literature relating to this topic. Methods: A systematic review was performed on the databases Pubmed and EMBASE to identify relevant studies. Two independent researchers read the abstracts and used the Quality in Prognostic Studies tool to assess the quality of the evidence. Results: Forty-five studies were identified from the current literature. Twenty studies investigated the role of serum soluble mesothelin with majority suggesting that it has variable utility as a baseline test but when measured serially correlates with treatment response and prognosis. Several studies demonstrated that serum osteopontin correlated with survival at baseline. Other biomarkers have shown prognostic utility in individual studies but are yet to be reproduced in large cohort studies. Conclusions: From the available literature no serum or pleural fluid biomarker was identified that could be recommended currently for routine clinical practice. However, a falling serum soluble mesothelin might correlate with treatment response and improved survival
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