395 research outputs found
An Efficient and Accurate Grid Method for Solving the Time-Dependent Schroedinger Equation: Application of Coulomb Wave Function DVR to Atomic Systems in Strong Laser Fields
We present an efficient and accurate grid method for solving the
time-dependent Schr\"{o}dinger equation of atomic systems interacting with
intense laser pulses. As usual, the angular part of the wave function is
expanded in terms of spherical harmonics. Instead of the usual finite
difference (FD) scheme, the radial coordinate is discretized using the discrete
variable representation which is constructed from the Coulomb wave function.
For an accurate description of the ionization dynamics of atomic systems, the
Coulomb wave function discrete variable representation (CWDVR) method needs
3-10 times less grid points than the FD method. The resultant grid points of
CWDVR distribute unevenly so that one has finer grid near the origin and
coarser one at larger distances. The other important advantage of the CWDVR
method is that it treats the Coulomb singularity accurately and gives a good
representation of continuum wave functions. The time propagation of the wave
function is implemented using the well-known Arnoldi method. As examples, the
present method is applied to the multiphoton ionization of both H and H in
intense laser fields. Short-time excitation and ionization dynamics of H by
static electric fields is also investigated. For a wide range of photon
energies and laser intensities, ionization rates calculated using this method
are in excellent agreement with those from other theoretical calculations.Comment: Submitted to Journal of Chemical Physic
Stem-like and highly invasive prostate cancer cells expressing CD44v8-10 marker originate from CD44-negative cells
In human prostate cancer (PCa), the neuroendocrine cells, expressing the prostate cancer stem cell (CSC) marker CD44, may be resistant to androgen ablation and promote tumor recurrence. During the study of heterogeneity of the highly aggressive neuroendocrine PCa cell lines PC3 and DU-145, we isolated and expanded in vitro a minor subpopulation of very small cells lacking CD44 (CD44neg). Unexpectedly, these sorted CD44neg cells rapidly and spontaneously converted to a stable CD44high phenotype specifically expressing the CD44v8-10 isoform which the sorted CD44high subpopulation failed to express. Surprisingly and potentially interesting, in these cells expression of CD44v8-10 was found to be induced in stem cell medium. CD44 variant isoforms are known to be more expressed in CSC and metastatic cells than CD44 standard isoform. In agreement, functional analysis of the two sorted and cultured subpopulations has shown that the CD44v8-10pos PC3 cells, resulting from the conversion of the CD44neg subpopulation, were more invasive in vitro and had a higher clonogenic potential than the sorted CD44high cells, in that they produced mainly holoclones, known to be enriched in stem-like cells. Of interest, the CD44v8-10 is more expressed in human PCa biopsies than in normal gland. The discovery of CD44v8-10pos cells with stem-like and invasive features, derived from a minoritarian CD44neg cell population in PCa, alerts on the high plasticity of stem-like markers and urges for prudency on the approaches to targeting the putative CSC
High-order harmonic generation in Xe, Kr, and Ar driven by a 2.1-\mu m source: high-order harmonic spectroscopy under macroscopic effects
We experimentally and numerically study the atomic response and pulse
propagation effects of high-order harmonics generated in Xe, Kr, and Ar driven
by a 2.1-\mu m infrared femtosecond light source. The light source is an
optical parametric chirped-pulse amplifier, and a modified strong-field
approximation and 3-dimensional pulse propagation code are used for the
numerical simulations. The extended cutoff in the long-wavelength driven
high-harmonic generation has revealed the spectral shaping of high-order
harmonics due to the atomic structure (or photo-recombination cross-section)
and the macroscopic effects, which are the main factors of determining the
conversion efficiency besides the driving wavelength. Using precise numerical
simulations to determine the macroscopic electron wavepacket, we are able to
extract the photo-recombination cross-sections from experimental high-order
harmonic spectra in the presence of macroscopic effects. We have experimentally
observed that the macroscopic effects shift the observed Cooper minimum of Kr
from 80 eV to 60-70 eV and wash out the Cooper minimum of Ar. Measured
high-harmonic conversion efficiencies per harmonic near the cutoff are ~10^{-9}
for all three gases.Comment: 19 pages, 8 figure
Entanglement Evolution in the Presence of Decoherence
The entanglement of two qubits, each defined as an effective two-level, spin
1/2 system, is investigated for the case that the qubits interact via a
Heisenberg XY interaction and are subject to decoherence due to population
relaxation and thermal effects. For zero temperature, the time dependent
concurrence is studied analytically and numerically for some typical initial
states, including a separable (unentangled) initial state. An analytical
formula for non-zero steady state concurrence is found for any initial state,
and optimal parameter values for maximizing steady state concurrence are given.
The steady state concurrence is found analytically to remain non-zero for low,
finite temperatures. We also identify the contributions of global and local
coherence to the steady state entanglement.Comment: 12 pages, 4 figures. The second version of this paper has been
significantly expanded in response to referee comments. The revised
manuscript has been accepted for publication in Journal of Physics
Onychomycosis: Recommendations for Diagnosis, Assessment of Treatment Efficacy, and Specialist Referral. The CONSONANCE Consensus Project
Introduction: Onychomycosis is the most common nail disorder in adults, with high recurrence and relapse rates. Its diagnosis may be difficult by non-experts because the clinical signs may overlap with other dermatoses. The treatment may be challenging, as it should be patient-tailored.
Methods: An online survey was conducted among European Nail Society (ENS) members to provide recommendations on the diagnosis and assessment of distal lateral subungual onychomycosis (DLSO) in non-specialized clinical environments, as well as recommendations for patient referral.
Results: DLSO diagnosis is predominantly based on clinical aspects, and microscopy and fungal culture are commonly employed to establish the diagnosis. Assessment of clinical features is the main method for DLSO follow-up, and the main criterion to define cure is a combination of mycologic cure and clinical cure. The most commonly selected treatments for onychomycosis include oral antifungals, topical antifungals, and nail debridement. According to the nail experts, predisposing factors of DLSO to be evaluated include concurrent tinea pedis diagnosis, immunocompromised status, and diabetes. The minimum clinical aspects to be evaluated for DLSO diagnosis should include subungual hyperkeratosis, white-yellow-orange subungual scales, and absence of salmon-pink coloration. Recommendations for clinical signs that should be evaluated to confirm treatment effectiveness include normal appearance and color of the nail, reduction or absence of scales under the nail, and absence of onycholysis. Recommendations for specialist referral include lack of treatment effectiveness, need of additional therapies, concurrent presence of other diseases or comorbidities, severe DLSO, and presence of a dermatophytoma or involvement of the nail matrix.
Conclusions: According to the surveyed nail experts, after evaluating clinical signs and predisposing factors for DLSO, the diagnosis should include subungual hyperkeratosis, nail color (yellow-orange), and onycholysis and thickening. In cases of severe DLSO, when there is treatment failure, concomitant diseases/comorbidities, presence of a dermatophytoma or involvement of the nail matrix, or involvement of several/all nails, referral should be considered
Relativistic transition wavelenghts and probabilities for spectral lines of Ne II
Transition wavelengths and probabilities for several 2p4 3p - 2p4 3s and 2p4
3d - 2p4 3p lines in fuorine-like neon ion (NeII) have been calculated within
the multiconfiguration Dirac-Fock (MCDF) method with quantum electrodynamics
(QED) corrections. The results are compared with all existing experimental and
theoretical data
Cyclin-Dependent Kinase 4/6 Inhibitors and Dermatologic Adverse Events: Results from the EADV Task Force "Dermatology for Cancer Patients"
Treatment with cyclin-dependent kinase 4/6 inhibitor (CDK4/6i), has demonstrated significantly improved progression-free survival in patients with hormone receptor-positive, HER2-negative, advanced breast cancer, when used in combination with endocrine therapies. However, limited data exists on its cutaneous adverse events (AE). The aim of our retrospective study was to investigate the prevalence, types and management of cutaneous AE during CDK4/6i. 79 adult advanced breast cancer patients affected by 125 skin adverse events during treatment with CDK4/6i were recruited at eleven centers. The most frequent cutaneous reactions were pruritus (49/79 patients), alopecia (25/79), and ec-zematous lesions (24/79). We showed that skin reactions are usually mild in severity, and prompt management may limit the negative impact on patients, facilitating beneficial continuation of oncologic treatment
Atomic photoionization experiment by harmonic-generation spectroscopy
Citation: Frolov, M. V., Sarantseva, T. S., Manakov, N. L., Fulfer, K. D., Wilson, B. P., Tross, J., . . . Trallero-Herrero, C. A. (2016). Atomic photoionization experiment by harmonic-generation spectroscopy. Physical Review A, 93(3), 5. doi:10.1103/PhysRevA.93.031403Measurements of the high-order-harmonic generation yield of the argon (Ar) atom driven by a strong elliptically polarized laser field are shown to completely determine the field-free differential photoionization cross section of Ar, i.e., the energy dependence of both the angle-integrated photoionization cross section and the angular distribution asymmetry parameter
Photoelectron Angular Distributions as a Probe of Anisotropic Electron-Ion Interactions
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