33 research outputs found
State transfer in dissipative and dephasing environments
By diagonalization of a generalized superoperator for solving the master
equation, we investigated effects of dissipative and dephasing environments on
quantum state transfer, as well as entanglement distribution and creation in
spin networks. Our results revealed that under the condition of the same
decoherence rate , the detrimental effects of the dissipative
environment are more severe than that of the dephasing environment. Beside
this, the critical time at which the transfer fidelity and the
concurrence attain their maxima arrives at the asymptotic value
quickly as the spin chain length increases. The transfer
fidelity of an excitation at time is independent of when the system
subjects to dissipative environment, while it decreases as increases when
the system subjects to dephasing environment. The average fidelity displays
three different patterns corresponding to , and . For
each pattern, the average fidelity at time is independent of when the
system subjects to dissipative environment, and decreases as increases when
the system subjects to dephasing environment. The maximum concurrence also
decreases as increases, and when , it arrives at an
asymptotic value determined by the decoherence rate and the structure
of the spin network.Comment: 12 pages, 6 figure
State transfer in intrinsic decoherence spin channels
By analytically solving the master equation, we investigate quantum state
transfer, creation and distribution of entanglement in the model of Milburn's
intrinsic decoherence. Our results reveal that the ideal spin channels will be
destroyed by the intrinsic decoherence environment, and the detrimental effects
become severe as the decoherence rate and the spin chain length
increase. For infinite evolution time, both the state transfer fidelity and the
concurrence of the created and distributed entanglement approach steady state
values, which are independent of the decoherence rate and decrease as
the spin chain length increases. Finally, we present two modified spin
chains which may serve as near perfect spin channels for long distance state
transfer even in the presence of intrinsic decoherence environments .Comment: 11 pages, 11 figure
Molecular Profiling Reveals Biologically Discrete Subsets and Pathways of Progression in Diffuse Glioma
Therapy development for adult diffuse glioma is hindered by incomplete knowledge of somatic glioma driving alterations and suboptimal disease classification. We defined the complete set of genes associated with 1,122 diffuse grade II-III-IV gliomas from The Cancer Genome Atlas and used molecular profiles to improve disease classification, identify molecular correlations, and provide insights into the progression from low- to high-grade disease. Whole-genome sequencing data analysis determined that ATRX but not TERT promoter mutations are associated with increased telomere length. Recent advances in glioma classification based on IDH mutation and 1p/19q co-deletion status were recapitulated through analysis of DNA methylation profiles, which identified clinically relevant molecular subsets. A subtype of IDH mutant glioma was associated with DNA demethylation and poor outcome; a group of IDH-wild-type diffuse glioma showed molecular similarity to pilocytic astrocytoma and relatively favorable survival. Understanding of cohesive disease groups may aid improved clinical outcomes
DISSEMINATED BACILLUS-CALMETTE-GU蒖IN INFECTIONS AND PRIMARY IMMUNODEFICIENCY DISORDERS IN SINGAPORE: A SINGLE CENTER 15-YEAR RETROSPECTIVE REVIEW
10.1016/j.ijid.2020.05.117International Journal of Infectious Diseases97117-12
A multicenter phase II trial of intrathecal topotecan in patients with meningeal malignancies
To determine the therapeutic efficacy (13-week and 26-week CNS progression-free survival [PFS], response rate, and overall survival) and safety of intraventricular (IVent) topotecan in patients with neoplastic meningitis (NM), we conducted a phase II, open-label, nonrandomized, single-arm trial of IVent topotecan in patients with NM using 400 μg of topotecan IVent twice weekly for 6 weeks, followed by evaluation with imaging, cerebrospinal fluid (CSF), and physical examinations. In the absence of disease progression, patients were then treated with IVent topotecan weekly for 6 weeks, twice monthly for 4 months, and monthly thereafter. Sixty-two patients (23 males and 39 females) were enrolled from April 2001 through March 2006. Median age and KPS at enrollment were 56 (range 5–83) and 80 (range 60–100), respectively. Primary cancers included breast (19), lung (13), CNS (14), and others (16). Forty patients (65%) completed the 6-week induction period, among whom 13 (21%) had CSF clearance of malignant cells. Kaplan-Meier estimates of PFS at 13 and 26 weeks were 30% (95% confidence interval [CI], 20%–45%) and 19% (95% CI, 11%–34%). Overall median survival (50 deaths) was 15 weeks (95% CI, 13–24 weeks). The most common side effect was chemical meningitis in 32% of patients (5% grade 3); 32% experienced no drug side effects. IVent topotecan is well tolerated, but provides no added benefit over other IVent therapies. Because of its modest side effect profile, combining IVent topotecan with other IVent or systemic interventions should be considered